Merge branch 'develop' into babolivier/mark_unread

62 files changed, 3254 insertions, 2236 deletions

diff --git a/synapse/rest/__init__.py b/synapse/rest/__init__.py
index 4a1fc2ec2b..46e458e95b 100644
--- a/synapse/rest/__init__.py
+++ b/synapse/rest/__init__.py
@@ -41,6 +41,7 @@ from synapse.rest.client.v2_alpha import (
     keys,
     notifications,
     openid,
+    password_policy,
     read_marker,
     receipts,
     register,
@@ -118,6 +119,7 @@ class ClientRestResource(JsonResource):
         capabilities.register_servlets(hs, client_resource)
         account_validity.register_servlets(hs, client_resource)
         relations.register_servlets(hs, client_resource)
+        password_policy.register_servlets(hs, client_resource)
 
         # moving to /_synapse/admin
         synapse.rest.admin.register_servlets_for_client_rest_resource(
diff --git a/synapse/rest/admin/__init__.py b/synapse/rest/admin/__init__.py
index 81b6bd8816..9eda592de9 100644
--- a/synapse/rest/admin/__init__.py
+++ b/synapse/rest/admin/__init__.py
@@ -14,64 +14,50 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import hashlib
-import hmac
 import logging
 import platform
 import re
 
-from six import text_type
-from six.moves import http_client
-
-from twisted.internet import defer
-
 import synapse
-from synapse.api.constants import Membership, UserTypes
 from synapse.api.errors import Codes, NotFoundError, SynapseError
 from synapse.http.server import JsonResource
-from synapse.http.servlet import (
-    RestServlet,
-    assert_params_in_dict,
-    parse_integer,
-    parse_json_object_from_request,
-    parse_string,
-)
+from synapse.http.servlet import RestServlet, parse_json_object_from_request
 from synapse.rest.admin._base import (
     assert_requester_is_admin,
-    assert_user_is_admin,
     historical_admin_path_patterns,
 )
+from synapse.rest.admin.devices import (
+    DeleteDevicesRestServlet,
+    DeviceRestServlet,
+    DevicesRestServlet,
+)
+from synapse.rest.admin.groups import DeleteGroupAdminRestServlet
 from synapse.rest.admin.media import ListMediaInRoom, register_servlets_for_media_repo
 from synapse.rest.admin.purge_room_servlet import PurgeRoomServlet
+from synapse.rest.admin.rooms import (
+    JoinRoomAliasServlet,
+    ListRoomRestServlet,
+    RoomRestServlet,
+    ShutdownRoomRestServlet,
+)
 from synapse.rest.admin.server_notice_servlet import SendServerNoticeServlet
-from synapse.rest.admin.users import UserAdminServlet
-from synapse.types import UserID, create_requester
+from synapse.rest.admin.users import (
+    AccountValidityRenewServlet,
+    DeactivateAccountRestServlet,
+    ResetPasswordRestServlet,
+    SearchUsersRestServlet,
+    UserAdminServlet,
+    UserRegisterServlet,
+    UserRestServletV2,
+    UsersRestServlet,
+    UsersRestServletV2,
+    WhoisRestServlet,
+)
 from synapse.util.versionstring import get_version_string
 
 logger = logging.getLogger(__name__)
 
 
-class UsersRestServlet(RestServlet):
-    PATTERNS = historical_admin_path_patterns("/users/(?P<user_id>[^/]*)$")
-
-    def __init__(self, hs):
-        self.hs = hs
-        self.auth = hs.get_auth()
-        self.handlers = hs.get_handlers()
-
-    @defer.inlineCallbacks
-    def on_GET(self, request, user_id):
-        target_user = UserID.from_string(user_id)
-        yield assert_requester_is_admin(self.auth, request)
-
-        if not self.hs.is_mine(target_user):
-            raise SynapseError(400, "Can only users a local user")
-
-        ret = yield self.handlers.admin_handler.get_users()
-
-        return 200, ret
-
-
 class VersionServlet(RestServlet):
     PATTERNS = (re.compile("^/_synapse/admin/v1/server_version$"),)
 
@@ -85,161 +71,6 @@ class VersionServlet(RestServlet):
         return 200, self.res
 
 
-class UserRegisterServlet(RestServlet):
-    """
-    Attributes:
-         NONCE_TIMEOUT (int): Seconds until a generated nonce won't be accepted
-         nonces (dict[str, int]): The nonces that we will accept. A dict of
-             nonce to the time it was generated, in int seconds.
-    """
-
-    PATTERNS = historical_admin_path_patterns("/register")
-    NONCE_TIMEOUT = 60
-
-    def __init__(self, hs):
-        self.handlers = hs.get_handlers()
-        self.reactor = hs.get_reactor()
-        self.nonces = {}
-        self.hs = hs
-
-    def _clear_old_nonces(self):
-        """
-        Clear out old nonces that are older than NONCE_TIMEOUT.
-        """
-        now = int(self.reactor.seconds())
-
-        for k, v in list(self.nonces.items()):
-            if now - v > self.NONCE_TIMEOUT:
-                del self.nonces[k]
-
-    def on_GET(self, request):
-        """
-        Generate a new nonce.
-        """
-        self._clear_old_nonces()
-
-        nonce = self.hs.get_secrets().token_hex(64)
-        self.nonces[nonce] = int(self.reactor.seconds())
-        return 200, {"nonce": nonce}
-
-    @defer.inlineCallbacks
-    def on_POST(self, request):
-        self._clear_old_nonces()
-
-        if not self.hs.config.registration_shared_secret:
-            raise SynapseError(400, "Shared secret registration is not enabled")
-
-        body = parse_json_object_from_request(request)
-
-        if "nonce" not in body:
-            raise SynapseError(400, "nonce must be specified", errcode=Codes.BAD_JSON)
-
-        nonce = body["nonce"]
-
-        if nonce not in self.nonces:
-            raise SynapseError(400, "unrecognised nonce")
-
-        # Delete the nonce, so it can't be reused, even if it's invalid
-        del self.nonces[nonce]
-
-        if "username" not in body:
-            raise SynapseError(
-                400, "username must be specified", errcode=Codes.BAD_JSON
-            )
-        else:
-            if (
-                not isinstance(body["username"], text_type)
-                or len(body["username"]) > 512
-            ):
-                raise SynapseError(400, "Invalid username")
-
-            username = body["username"].encode("utf-8")
-            if b"\x00" in username:
-                raise SynapseError(400, "Invalid username")
-
-        if "password" not in body:
-            raise SynapseError(
-                400, "password must be specified", errcode=Codes.BAD_JSON
-            )
-        else:
-            if (
-                not isinstance(body["password"], text_type)
-                or len(body["password"]) > 512
-            ):
-                raise SynapseError(400, "Invalid password")
-
-            password = body["password"].encode("utf-8")
-            if b"\x00" in password:
-                raise SynapseError(400, "Invalid password")
-
-        admin = body.get("admin", None)
-        user_type = body.get("user_type", None)
-
-        if user_type is not None and user_type not in UserTypes.ALL_USER_TYPES:
-            raise SynapseError(400, "Invalid user type")
-
-        got_mac = body["mac"]
-
-        want_mac = hmac.new(
-            key=self.hs.config.registration_shared_secret.encode(),
-            digestmod=hashlib.sha1,
-        )
-        want_mac.update(nonce.encode("utf8"))
-        want_mac.update(b"\x00")
-        want_mac.update(username)
-        want_mac.update(b"\x00")
-        want_mac.update(password)
-        want_mac.update(b"\x00")
-        want_mac.update(b"admin" if admin else b"notadmin")
-        if user_type:
-            want_mac.update(b"\x00")
-            want_mac.update(user_type.encode("utf8"))
-        want_mac = want_mac.hexdigest()
-
-        if not hmac.compare_digest(want_mac.encode("ascii"), got_mac.encode("ascii")):
-            raise SynapseError(403, "HMAC incorrect")
-
-        # Reuse the parts of RegisterRestServlet to reduce code duplication
-        from synapse.rest.client.v2_alpha.register import RegisterRestServlet
-
-        register = RegisterRestServlet(self.hs)
-
-        user_id = yield register.registration_handler.register_user(
-            localpart=body["username"].lower(),
-            password=body["password"],
-            admin=bool(admin),
-            user_type=user_type,
-        )
-
-        result = yield register._create_registration_details(user_id, body)
-        return 200, result
-
-
-class WhoisRestServlet(RestServlet):
-    PATTERNS = historical_admin_path_patterns("/whois/(?P<user_id>[^/]*)")
-
-    def __init__(self, hs):
-        self.hs = hs
-        self.auth = hs.get_auth()
-        self.handlers = hs.get_handlers()
-
-    @defer.inlineCallbacks
-    def on_GET(self, request, user_id):
-        target_user = UserID.from_string(user_id)
-        requester = yield self.auth.get_user_by_req(request)
-        auth_user = requester.user
-
-        if target_user != auth_user:
-            yield assert_user_is_admin(self.auth, auth_user)
-
-        if not self.hs.is_mine(target_user):
-            raise SynapseError(400, "Can only whois a local user")
-
-        ret = yield self.handlers.admin_handler.get_whois(target_user)
-
-        return 200, ret
-
-
 class PurgeHistoryRestServlet(RestServlet):
     PATTERNS = historical_admin_path_patterns(
         "/purge_history/(?P<room_id>[^/]*)(/(?P<event_id>[^/]+))?"
@@ -255,9 +86,8 @@ class PurgeHistoryRestServlet(RestServlet):
         self.store = hs.get_datastore()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_POST(self, request, room_id, event_id):
-        yield assert_requester_is_admin(self.auth, request)
+    async def on_POST(self, request, room_id, event_id):
+        await assert_requester_is_admin(self.auth, request)
 
         body = parse_json_object_from_request(request, allow_empty_body=True)
 
@@ -270,12 +100,12 @@ class PurgeHistoryRestServlet(RestServlet):
             event_id = body.get("purge_up_to_event_id")
 
         if event_id is not None:
-            event = yield self.store.get_event(event_id)
+            event = await self.store.get_event(event_id)
 
             if event.room_id != room_id:
                 raise SynapseError(400, "Event is for wrong room.")
 
-            token = yield self.store.get_topological_token_for_event(event_id)
+            token = await self.store.get_topological_token_for_event(event_id)
 
             logger.info("[purge] purging up to token %s (event_id %s)", token, event_id)
         elif "purge_up_to_ts" in body:
@@ -285,15 +115,13 @@ class PurgeHistoryRestServlet(RestServlet):
                     400, "purge_up_to_ts must be an int", errcode=Codes.BAD_JSON
                 )
 
-            stream_ordering = (yield self.store.find_first_stream_ordering_after_ts(ts))
+            stream_ordering = await self.store.find_first_stream_ordering_after_ts(ts)
 
-            r = (
-                yield self.store.get_room_event_after_stream_ordering(
-                    room_id, stream_ordering
-                )
+            r = await self.store.get_room_event_before_stream_ordering(
+                room_id, stream_ordering
             )
             if not r:
-                logger.warn(
+                logger.warning(
                     "[purge] purging events not possible: No event found "
                     "(received_ts %i => stream_ordering %i)",
                     ts,
@@ -318,7 +146,7 @@ class PurgeHistoryRestServlet(RestServlet):
                 errcode=Codes.BAD_JSON,
             )
 
-        purge_id = yield self.pagination_handler.start_purge_history(
+        purge_id = self.pagination_handler.start_purge_history(
             room_id, token, delete_local_events=delete_local_events
         )
 
@@ -339,9 +167,8 @@ class PurgeHistoryStatusRestServlet(RestServlet):
         self.pagination_handler = hs.get_pagination_handler()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, purge_id):
-        yield assert_requester_is_admin(self.auth, request)
+    async def on_GET(self, request, purge_id):
+        await assert_requester_is_admin(self.auth, request)
 
         purge_status = self.pagination_handler.get_purge_status(purge_id)
         if purge_status is None:
@@ -350,375 +177,6 @@ class PurgeHistoryStatusRestServlet(RestServlet):
         return 200, purge_status.asdict()
 
 
-class DeactivateAccountRestServlet(RestServlet):
-    PATTERNS = historical_admin_path_patterns("/deactivate/(?P<target_user_id>[^/]*)")
-
-    def __init__(self, hs):
-        self._deactivate_account_handler = hs.get_deactivate_account_handler()
-        self.auth = hs.get_auth()
-
-    @defer.inlineCallbacks
-    def on_POST(self, request, target_user_id):
-        yield assert_requester_is_admin(self.auth, request)
-        body = parse_json_object_from_request(request, allow_empty_body=True)
-        erase = body.get("erase", False)
-        if not isinstance(erase, bool):
-            raise SynapseError(
-                http_client.BAD_REQUEST,
-                "Param 'erase' must be a boolean, if given",
-                Codes.BAD_JSON,
-            )
-
-        UserID.from_string(target_user_id)
-
-        result = yield self._deactivate_account_handler.deactivate_account(
-            target_user_id, erase
-        )
-        if result:
-            id_server_unbind_result = "success"
-        else:
-            id_server_unbind_result = "no-support"
-
-        return 200, {"id_server_unbind_result": id_server_unbind_result}
-
-
-class ShutdownRoomRestServlet(RestServlet):
-    """Shuts down a room by removing all local users from the room and blocking
-    all future invites and joins to the room. Any local aliases will be repointed
-    to a new room created by `new_room_user_id` and kicked users will be auto
-    joined to the new room.
-    """
-
-    PATTERNS = historical_admin_path_patterns("/shutdown_room/(?P<room_id>[^/]+)")
-
-    DEFAULT_MESSAGE = (
-        "Sharing illegal content on this server is not permitted and rooms in"
-        " violation will be blocked."
-    )
-
-    def __init__(self, hs):
-        self.hs = hs
-        self.store = hs.get_datastore()
-        self.state = hs.get_state_handler()
-        self._room_creation_handler = hs.get_room_creation_handler()
-        self.event_creation_handler = hs.get_event_creation_handler()
-        self.room_member_handler = hs.get_room_member_handler()
-        self.auth = hs.get_auth()
-
-    @defer.inlineCallbacks
-    def on_POST(self, request, room_id):
-        requester = yield self.auth.get_user_by_req(request)
-        yield assert_user_is_admin(self.auth, requester.user)
-
-        content = parse_json_object_from_request(request)
-        assert_params_in_dict(content, ["new_room_user_id"])
-        new_room_user_id = content["new_room_user_id"]
-
-        room_creator_requester = create_requester(new_room_user_id)
-
-        message = content.get("message", self.DEFAULT_MESSAGE)
-        room_name = content.get("room_name", "Content Violation Notification")
-
-        info = yield self._room_creation_handler.create_room(
-            room_creator_requester,
-            config={
-                "preset": "public_chat",
-                "name": room_name,
-                "power_level_content_override": {"users_default": -10},
-            },
-            ratelimit=False,
-        )
-        new_room_id = info["room_id"]
-
-        requester_user_id = requester.user.to_string()
-
-        logger.info(
-            "Shutting down room %r, joining to new room: %r", room_id, new_room_id
-        )
-
-        # This will work even if the room is already blocked, but that is
-        # desirable in case the first attempt at blocking the room failed below.
-        yield self.store.block_room(room_id, requester_user_id)
-
-        users = yield self.state.get_current_users_in_room(room_id)
-        kicked_users = []
-        failed_to_kick_users = []
-        for user_id in users:
-            if not self.hs.is_mine_id(user_id):
-                continue
-
-            logger.info("Kicking %r from %r...", user_id, room_id)
-
-            try:
-                target_requester = create_requester(user_id)
-                yield self.room_member_handler.update_membership(
-                    requester=target_requester,
-                    target=target_requester.user,
-                    room_id=room_id,
-                    action=Membership.LEAVE,
-                    content={},
-                    ratelimit=False,
-                    require_consent=False,
-                )
-
-                yield self.room_member_handler.forget(target_requester.user, room_id)
-
-                yield self.room_member_handler.update_membership(
-                    requester=target_requester,
-                    target=target_requester.user,
-                    room_id=new_room_id,
-                    action=Membership.JOIN,
-                    content={},
-                    ratelimit=False,
-                    require_consent=False,
-                )
-
-                kicked_users.append(user_id)
-            except Exception:
-                logger.exception(
-                    "Failed to leave old room and join new room for %r", user_id
-                )
-                failed_to_kick_users.append(user_id)
-
-        yield self.event_creation_handler.create_and_send_nonmember_event(
-            room_creator_requester,
-            {
-                "type": "m.room.message",
-                "content": {"body": message, "msgtype": "m.text"},
-                "room_id": new_room_id,
-                "sender": new_room_user_id,
-            },
-            ratelimit=False,
-        )
-
-        aliases_for_room = yield self.store.get_aliases_for_room(room_id)
-
-        yield self.store.update_aliases_for_room(
-            room_id, new_room_id, requester_user_id
-        )
-
-        return (
-            200,
-            {
-                "kicked_users": kicked_users,
-                "failed_to_kick_users": failed_to_kick_users,
-                "local_aliases": aliases_for_room,
-                "new_room_id": new_room_id,
-            },
-        )
-
-
-class ResetPasswordRestServlet(RestServlet):
-    """Post request to allow an administrator reset password for a user.
-    This needs user to have administrator access in Synapse.
-        Example:
-            http://localhost:8008/_synapse/admin/v1/reset_password/
-            @user:to_reset_password?access_token=admin_access_token
-        JsonBodyToSend:
-            {
-                "new_password": "secret"
-            }
-        Returns:
-            200 OK with empty object if success otherwise an error.
-        """
-
-    PATTERNS = historical_admin_path_patterns(
-        "/reset_password/(?P<target_user_id>[^/]*)"
-    )
-
-    def __init__(self, hs):
-        self.store = hs.get_datastore()
-        self.hs = hs
-        self.auth = hs.get_auth()
-        self._set_password_handler = hs.get_set_password_handler()
-
-    @defer.inlineCallbacks
-    def on_POST(self, request, target_user_id):
-        """Post request to allow an administrator reset password for a user.
-        This needs user to have administrator access in Synapse.
-        """
-        requester = yield self.auth.get_user_by_req(request)
-        yield assert_user_is_admin(self.auth, requester.user)
-
-        UserID.from_string(target_user_id)
-
-        params = parse_json_object_from_request(request)
-        assert_params_in_dict(params, ["new_password"])
-        new_password = params["new_password"]
-
-        yield self._set_password_handler.set_password(
-            target_user_id, new_password, requester
-        )
-        return 200, {}
-
-
-class GetUsersPaginatedRestServlet(RestServlet):
-    """Get request to get specific number of users from Synapse.
-    This needs user to have administrator access in Synapse.
-        Example:
-            http://localhost:8008/_synapse/admin/v1/users_paginate/
-            @admin:user?access_token=admin_access_token&start=0&limit=10
-        Returns:
-            200 OK with json object {list[dict[str, Any]], count} or empty object.
-        """
-
-    PATTERNS = historical_admin_path_patterns(
-        "/users_paginate/(?P<target_user_id>[^/]*)"
-    )
-
-    def __init__(self, hs):
-        self.store = hs.get_datastore()
-        self.hs = hs
-        self.auth = hs.get_auth()
-        self.handlers = hs.get_handlers()
-
-    @defer.inlineCallbacks
-    def on_GET(self, request, target_user_id):
-        """Get request to get specific number of users from Synapse.
-        This needs user to have administrator access in Synapse.
-        """
-        yield assert_requester_is_admin(self.auth, request)
-
-        target_user = UserID.from_string(target_user_id)
-
-        if not self.hs.is_mine(target_user):
-            raise SynapseError(400, "Can only users a local user")
-
-        order = "name"  # order by name in user table
-        start = parse_integer(request, "start", required=True)
-        limit = parse_integer(request, "limit", required=True)
-
-        logger.info("limit: %s, start: %s", limit, start)
-
-        ret = yield self.handlers.admin_handler.get_users_paginate(order, start, limit)
-        return 200, ret
-
-    @defer.inlineCallbacks
-    def on_POST(self, request, target_user_id):
-        """Post request to get specific number of users from Synapse..
-        This needs user to have administrator access in Synapse.
-        Example:
-            http://localhost:8008/_synapse/admin/v1/users_paginate/
-            @admin:user?access_token=admin_access_token
-        JsonBodyToSend:
-            {
-                "start": "0",
-                "limit": "10
-            }
-        Returns:
-            200 OK with json object {list[dict[str, Any]], count} or empty object.
-        """
-        yield assert_requester_is_admin(self.auth, request)
-        UserID.from_string(target_user_id)
-
-        order = "name"  # order by name in user table
-        params = parse_json_object_from_request(request)
-        assert_params_in_dict(params, ["limit", "start"])
-        limit = params["limit"]
-        start = params["start"]
-        logger.info("limit: %s, start: %s", limit, start)
-
-        ret = yield self.handlers.admin_handler.get_users_paginate(order, start, limit)
-        return 200, ret
-
-
-class SearchUsersRestServlet(RestServlet):
-    """Get request to search user table for specific users according to
-    search term.
-    This needs user to have administrator access in Synapse.
-        Example:
-            http://localhost:8008/_synapse/admin/v1/search_users/
-            @admin:user?access_token=admin_access_token&term=alice
-        Returns:
-            200 OK with json object {list[dict[str, Any]], count} or empty object.
-    """
-
-    PATTERNS = historical_admin_path_patterns("/search_users/(?P<target_user_id>[^/]*)")
-
-    def __init__(self, hs):
-        self.store = hs.get_datastore()
-        self.hs = hs
-        self.auth = hs.get_auth()
-        self.handlers = hs.get_handlers()
-
-    @defer.inlineCallbacks
-    def on_GET(self, request, target_user_id):
-        """Get request to search user table for specific users according to
-        search term.
-        This needs user to have a administrator access in Synapse.
-        """
-        yield assert_requester_is_admin(self.auth, request)
-
-        target_user = UserID.from_string(target_user_id)
-
-        # To allow all users to get the users list
-        # if not is_admin and target_user != auth_user:
-        #     raise AuthError(403, "You are not a server admin")
-
-        if not self.hs.is_mine(target_user):
-            raise SynapseError(400, "Can only users a local user")
-
-        term = parse_string(request, "term", required=True)
-        logger.info("term: %s ", term)
-
-        ret = yield self.handlers.admin_handler.search_users(term)
-        return 200, ret
-
-
-class DeleteGroupAdminRestServlet(RestServlet):
-    """Allows deleting of local groups
-    """
-
-    PATTERNS = historical_admin_path_patterns("/delete_group/(?P<group_id>[^/]*)")
-
-    def __init__(self, hs):
-        self.group_server = hs.get_groups_server_handler()
-        self.is_mine_id = hs.is_mine_id
-        self.auth = hs.get_auth()
-
-    @defer.inlineCallbacks
-    def on_POST(self, request, group_id):
-        requester = yield self.auth.get_user_by_req(request)
-        yield assert_user_is_admin(self.auth, requester.user)
-
-        if not self.is_mine_id(group_id):
-            raise SynapseError(400, "Can only delete local groups")
-
-        yield self.group_server.delete_group(group_id, requester.user.to_string())
-        return 200, {}
-
-
-class AccountValidityRenewServlet(RestServlet):
-    PATTERNS = historical_admin_path_patterns("/account_validity/validity$")
-
-    def __init__(self, hs):
-        """
-        Args:
-            hs (synapse.server.HomeServer): server
-        """
-        self.hs = hs
-        self.account_activity_handler = hs.get_account_validity_handler()
-        self.auth = hs.get_auth()
-
-    @defer.inlineCallbacks
-    def on_POST(self, request):
-        yield assert_requester_is_admin(self.auth, request)
-
-        body = parse_json_object_from_request(request)
-
-        if "user_id" not in body:
-            raise SynapseError(400, "Missing property 'user_id' in the request body")
-
-        expiration_ts = yield self.account_activity_handler.renew_account_for_user(
-            body["user_id"],
-            body.get("expiration_ts"),
-            not body.get("enable_renewal_emails", True),
-        )
-
-        res = {"expiration_ts": expiration_ts}
-        return 200, res
-
-
 ########################################################################################
 #
 # please don't add more servlets here: this file is already long and unwieldy. Put
@@ -740,10 +198,18 @@ def register_servlets(hs, http_server):
     Register all the admin servlets.
     """
     register_servlets_for_client_rest_resource(hs, http_server)
+    ListRoomRestServlet(hs).register(http_server)
+    RoomRestServlet(hs).register(http_server)
+    JoinRoomAliasServlet(hs).register(http_server)
     PurgeRoomServlet(hs).register(http_server)
     SendServerNoticeServlet(hs).register(http_server)
     VersionServlet(hs).register(http_server)
     UserAdminServlet(hs).register(http_server)
+    UserRestServletV2(hs).register(http_server)
+    UsersRestServletV2(hs).register(http_server)
+    DeviceRestServlet(hs).register(http_server)
+    DevicesRestServlet(hs).register(http_server)
+    DeleteDevicesRestServlet(hs).register(http_server)
 
 
 def register_servlets_for_client_rest_resource(hs, http_server):
@@ -754,7 +220,6 @@ def register_servlets_for_client_rest_resource(hs, http_server):
     PurgeHistoryRestServlet(hs).register(http_server)
     UsersRestServlet(hs).register(http_server)
     ResetPasswordRestServlet(hs).register(http_server)
-    GetUsersPaginatedRestServlet(hs).register(http_server)
     SearchUsersRestServlet(hs).register(http_server)
     ShutdownRoomRestServlet(hs).register(http_server)
     UserRegisterServlet(hs).register(http_server)
diff --git a/synapse/rest/admin/_base.py b/synapse/rest/admin/_base.py
index 5a9b08d3ef..d82eaf5e38 100644
--- a/synapse/rest/admin/_base.py
+++ b/synapse/rest/admin/_base.py
@@ -15,9 +15,11 @@
 
 import re
 
-from twisted.internet import defer
+import twisted.web.server
 
+import synapse.api.auth
 from synapse.api.errors import AuthError
+from synapse.types import UserID
 
 
 def historical_admin_path_patterns(path_regex):
@@ -31,7 +33,7 @@ def historical_admin_path_patterns(path_regex):
     Note that this should only be used for existing endpoints: new ones should just
     register for the /_synapse/admin path.
     """
-    return list(
+    return [
         re.compile(prefix + path_regex)
         for prefix in (
             "^/_synapse/admin/v1",
@@ -39,46 +41,50 @@ def historical_admin_path_patterns(path_regex):
             "^/_matrix/client/unstable/admin",
             "^/_matrix/client/r0/admin",
         )
-    )
+    ]
 
 
-@defer.inlineCallbacks
-def assert_requester_is_admin(auth, request):
-    """Verify that the requester is an admin user
-
-    WARNING: MAKE SURE YOU YIELD ON THE RESULT!
+def admin_patterns(path_regex: str):
+    """Returns the list of patterns for an admin endpoint
 
     Args:
-        auth (synapse.api.auth.Auth):
-        request (twisted.web.server.Request): incoming request
+        path_regex: The regex string to match. This should NOT have a ^
+            as this will be prefixed.
 
     Returns:
-        Deferred
+        A list of regex patterns.
+    """
+    admin_prefix = "^/_synapse/admin/v1"
+    patterns = [re.compile(admin_prefix + path_regex)]
+    return patterns
+
+
+async def assert_requester_is_admin(
+    auth: synapse.api.auth.Auth, request: twisted.web.server.Request
+) -> None:
+    """Verify that the requester is an admin user
+
+    Args:
+        auth: api.auth.Auth singleton
+        request: incoming request
 
     Raises:
-        AuthError if the requester is not an admin
+        AuthError if the requester is not a server admin
     """
-    requester = yield auth.get_user_by_req(request)
-    yield assert_user_is_admin(auth, requester.user)
+    requester = await auth.get_user_by_req(request)
+    await assert_user_is_admin(auth, requester.user)
 
 
-@defer.inlineCallbacks
-def assert_user_is_admin(auth, user_id):
+async def assert_user_is_admin(auth: synapse.api.auth.Auth, user_id: UserID) -> None:
     """Verify that the given user is an admin user
 
-    WARNING: MAKE SURE YOU YIELD ON THE RESULT!
-
     Args:
-        auth (synapse.api.auth.Auth):
-        user_id (UserID):
-
-    Returns:
-        Deferred
+        auth: api.auth.Auth singleton
+        user_id: user to check
 
     Raises:
-        AuthError if the user is not an admin
+        AuthError if the user is not a server admin
     """
-
-    is_admin = yield auth.is_server_admin(user_id)
+    is_admin = await auth.is_server_admin(user_id)
     if not is_admin:
         raise AuthError(403, "You are not a server admin")
diff --git a/synapse/rest/admin/devices.py b/synapse/rest/admin/devices.py
new file mode 100644
index 0000000000..8d32677339
--- /dev/null
+++ b/synapse/rest/admin/devices.py
@@ -0,0 +1,161 @@
+# -*- coding: utf-8 -*-
+# Copyright 2020 Dirk Klimpel
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import logging
+import re
+
+from synapse.api.errors import NotFoundError, SynapseError
+from synapse.http.servlet import (
+    RestServlet,
+    assert_params_in_dict,
+    parse_json_object_from_request,
+)
+from synapse.rest.admin._base import assert_requester_is_admin
+from synapse.types import UserID
+
+logger = logging.getLogger(__name__)
+
+
+class DeviceRestServlet(RestServlet):
+    """
+    Get, update or delete the given user's device
+    """
+
+    PATTERNS = (
+        re.compile(
+            "^/_synapse/admin/v2/users/(?P<user_id>[^/]*)/devices/(?P<device_id>[^/]*)$"
+        ),
+    )
+
+    def __init__(self, hs):
+        super(DeviceRestServlet, self).__init__()
+        self.hs = hs
+        self.auth = hs.get_auth()
+        self.device_handler = hs.get_device_handler()
+        self.store = hs.get_datastore()
+
+    async def on_GET(self, request, user_id, device_id):
+        await assert_requester_is_admin(self.auth, request)
+
+        target_user = UserID.from_string(user_id)
+        if not self.hs.is_mine(target_user):
+            raise SynapseError(400, "Can only lookup local users")
+
+        u = await self.store.get_user_by_id(target_user.to_string())
+        if u is None:
+            raise NotFoundError("Unknown user")
+
+        device = await self.device_handler.get_device(
+            target_user.to_string(), device_id
+        )
+        return 200, device
+
+    async def on_DELETE(self, request, user_id, device_id):
+        await assert_requester_is_admin(self.auth, request)
+
+        target_user = UserID.from_string(user_id)
+        if not self.hs.is_mine(target_user):
+            raise SynapseError(400, "Can only lookup local users")
+
+        u = await self.store.get_user_by_id(target_user.to_string())
+        if u is None:
+            raise NotFoundError("Unknown user")
+
+        await self.device_handler.delete_device(target_user.to_string(), device_id)
+        return 200, {}
+
+    async def on_PUT(self, request, user_id, device_id):
+        await assert_requester_is_admin(self.auth, request)
+
+        target_user = UserID.from_string(user_id)
+        if not self.hs.is_mine(target_user):
+            raise SynapseError(400, "Can only lookup local users")
+
+        u = await self.store.get_user_by_id(target_user.to_string())
+        if u is None:
+            raise NotFoundError("Unknown user")
+
+        body = parse_json_object_from_request(request, allow_empty_body=True)
+        await self.device_handler.update_device(
+            target_user.to_string(), device_id, body
+        )
+        return 200, {}
+
+
+class DevicesRestServlet(RestServlet):
+    """
+    Retrieve the given user's devices
+    """
+
+    PATTERNS = (re.compile("^/_synapse/admin/v2/users/(?P<user_id>[^/]*)/devices$"),)
+
+    def __init__(self, hs):
+        """
+        Args:
+            hs (synapse.server.HomeServer): server
+        """
+        self.hs = hs
+        self.auth = hs.get_auth()
+        self.device_handler = hs.get_device_handler()
+        self.store = hs.get_datastore()
+
+    async def on_GET(self, request, user_id):
+        await assert_requester_is_admin(self.auth, request)
+
+        target_user = UserID.from_string(user_id)
+        if not self.hs.is_mine(target_user):
+            raise SynapseError(400, "Can only lookup local users")
+
+        u = await self.store.get_user_by_id(target_user.to_string())
+        if u is None:
+            raise NotFoundError("Unknown user")
+
+        devices = await self.device_handler.get_devices_by_user(target_user.to_string())
+        return 200, {"devices": devices}
+
+
+class DeleteDevicesRestServlet(RestServlet):
+    """
+    API for bulk deletion of devices. Accepts a JSON object with a devices
+    key which lists the device_ids to delete.
+    """
+
+    PATTERNS = (
+        re.compile("^/_synapse/admin/v2/users/(?P<user_id>[^/]*)/delete_devices$"),
+    )
+
+    def __init__(self, hs):
+        self.hs = hs
+        self.auth = hs.get_auth()
+        self.device_handler = hs.get_device_handler()
+        self.store = hs.get_datastore()
+
+    async def on_POST(self, request, user_id):
+        await assert_requester_is_admin(self.auth, request)
+
+        target_user = UserID.from_string(user_id)
+        if not self.hs.is_mine(target_user):
+            raise SynapseError(400, "Can only lookup local users")
+
+        u = await self.store.get_user_by_id(target_user.to_string())
+        if u is None:
+            raise NotFoundError("Unknown user")
+
+        body = parse_json_object_from_request(request, allow_empty_body=False)
+        assert_params_in_dict(body, ["devices"])
+
+        await self.device_handler.delete_devices(
+            target_user.to_string(), body["devices"]
+        )
+        return 200, {}
diff --git a/synapse/rest/admin/groups.py b/synapse/rest/admin/groups.py
new file mode 100644
index 0000000000..0b54ca09f4
--- /dev/null
+++ b/synapse/rest/admin/groups.py
@@ -0,0 +1,46 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import logging
+
+from synapse.api.errors import SynapseError
+from synapse.http.servlet import RestServlet
+from synapse.rest.admin._base import (
+    assert_user_is_admin,
+    historical_admin_path_patterns,
+)
+
+logger = logging.getLogger(__name__)
+
+
+class DeleteGroupAdminRestServlet(RestServlet):
+    """Allows deleting of local groups
+    """
+
+    PATTERNS = historical_admin_path_patterns("/delete_group/(?P<group_id>[^/]*)")
+
+    def __init__(self, hs):
+        self.group_server = hs.get_groups_server_handler()
+        self.is_mine_id = hs.is_mine_id
+        self.auth = hs.get_auth()
+
+    async def on_POST(self, request, group_id):
+        requester = await self.auth.get_user_by_req(request)
+        await assert_user_is_admin(self.auth, requester.user)
+
+        if not self.is_mine_id(group_id):
+            raise SynapseError(400, "Can only delete local groups")
+
+        await self.group_server.delete_group(group_id, requester.user.to_string())
+        return 200, {}
diff --git a/synapse/rest/admin/media.py b/synapse/rest/admin/media.py
index ed7086d09c..ee75095c0e 100644
--- a/synapse/rest/admin/media.py
+++ b/synapse/rest/admin/media.py
@@ -16,8 +16,6 @@
 
 import logging
 
-from twisted.internet import defer
-
 from synapse.api.errors import AuthError
 from synapse.http.servlet import RestServlet, parse_integer
 from synapse.rest.admin._base import (
@@ -34,24 +32,85 @@ class QuarantineMediaInRoom(RestServlet):
     this server.
     """
 
-    PATTERNS = historical_admin_path_patterns("/quarantine_media/(?P<room_id>[^/]+)")
+    PATTERNS = (
+        historical_admin_path_patterns("/room/(?P<room_id>[^/]+)/media/quarantine")
+        +
+        # This path kept around for legacy reasons
+        historical_admin_path_patterns("/quarantine_media/(?P<room_id>[^/]+)")
+    )
 
     def __init__(self, hs):
         self.store = hs.get_datastore()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_POST(self, request, room_id):
-        requester = yield self.auth.get_user_by_req(request)
-        yield assert_user_is_admin(self.auth, requester.user)
+    async def on_POST(self, request, room_id: str):
+        requester = await self.auth.get_user_by_req(request)
+        await assert_user_is_admin(self.auth, requester.user)
+
+        logging.info("Quarantining room: %s", room_id)
 
-        num_quarantined = yield self.store.quarantine_media_ids_in_room(
+        # Quarantine all media in this room
+        num_quarantined = await self.store.quarantine_media_ids_in_room(
             room_id, requester.user.to_string()
         )
 
         return 200, {"num_quarantined": num_quarantined}
 
 
+class QuarantineMediaByUser(RestServlet):
+    """Quarantines all local media by a given user so that no one can download it via
+    this server.
+    """
+
+    PATTERNS = historical_admin_path_patterns(
+        "/user/(?P<user_id>[^/]+)/media/quarantine"
+    )
+
+    def __init__(self, hs):
+        self.store = hs.get_datastore()
+        self.auth = hs.get_auth()
+
+    async def on_POST(self, request, user_id: str):
+        requester = await self.auth.get_user_by_req(request)
+        await assert_user_is_admin(self.auth, requester.user)
+
+        logging.info("Quarantining local media by user: %s", user_id)
+
+        # Quarantine all media this user has uploaded
+        num_quarantined = await self.store.quarantine_media_ids_by_user(
+            user_id, requester.user.to_string()
+        )
+
+        return 200, {"num_quarantined": num_quarantined}
+
+
+class QuarantineMediaByID(RestServlet):
+    """Quarantines local or remote media by a given ID so that no one can download
+    it via this server.
+    """
+
+    PATTERNS = historical_admin_path_patterns(
+        "/media/quarantine/(?P<server_name>[^/]+)/(?P<media_id>[^/]+)"
+    )
+
+    def __init__(self, hs):
+        self.store = hs.get_datastore()
+        self.auth = hs.get_auth()
+
+    async def on_POST(self, request, server_name: str, media_id: str):
+        requester = await self.auth.get_user_by_req(request)
+        await assert_user_is_admin(self.auth, requester.user)
+
+        logging.info("Quarantining local media by ID: %s/%s", server_name, media_id)
+
+        # Quarantine this media id
+        await self.store.quarantine_media_by_id(
+            server_name, media_id, requester.user.to_string()
+        )
+
+        return 200, {}
+
+
 class ListMediaInRoom(RestServlet):
     """Lists all of the media in a given room.
     """
@@ -62,14 +121,13 @@ class ListMediaInRoom(RestServlet):
         self.store = hs.get_datastore()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, room_id):
-        requester = yield self.auth.get_user_by_req(request)
-        is_admin = yield self.auth.is_server_admin(requester.user)
+    async def on_GET(self, request, room_id):
+        requester = await self.auth.get_user_by_req(request)
+        is_admin = await self.auth.is_server_admin(requester.user)
         if not is_admin:
             raise AuthError(403, "You are not a server admin")
 
-        local_mxcs, remote_mxcs = yield self.store.get_media_mxcs_in_room(room_id)
+        local_mxcs, remote_mxcs = await self.store.get_media_mxcs_in_room(room_id)
 
         return 200, {"local": local_mxcs, "remote": remote_mxcs}
 
@@ -81,14 +139,13 @@ class PurgeMediaCacheRestServlet(RestServlet):
         self.media_repository = hs.get_media_repository()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_POST(self, request):
-        yield assert_requester_is_admin(self.auth, request)
+    async def on_POST(self, request):
+        await assert_requester_is_admin(self.auth, request)
 
         before_ts = parse_integer(request, "before_ts", required=True)
         logger.info("before_ts: %r", before_ts)
 
-        ret = yield self.media_repository.delete_old_remote_media(before_ts)
+        ret = await self.media_repository.delete_old_remote_media(before_ts)
 
         return 200, ret
 
@@ -99,4 +156,6 @@ def register_servlets_for_media_repo(hs, http_server):
     """
     PurgeMediaCacheRestServlet(hs).register(http_server)
     QuarantineMediaInRoom(hs).register(http_server)
+    QuarantineMediaByID(hs).register(http_server)
+    QuarantineMediaByUser(hs).register(http_server)
     ListMediaInRoom(hs).register(http_server)
diff --git a/synapse/rest/admin/rooms.py b/synapse/rest/admin/rooms.py
new file mode 100644
index 0000000000..8173baef8f
--- /dev/null
+++ b/synapse/rest/admin/rooms.py
@@ -0,0 +1,364 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import logging
+from typing import List, Optional
+
+from synapse.api.constants import EventTypes, JoinRules, Membership
+from synapse.api.errors import Codes, NotFoundError, SynapseError
+from synapse.http.servlet import (
+    RestServlet,
+    assert_params_in_dict,
+    parse_integer,
+    parse_json_object_from_request,
+    parse_string,
+)
+from synapse.rest.admin._base import (
+    admin_patterns,
+    assert_requester_is_admin,
+    assert_user_is_admin,
+    historical_admin_path_patterns,
+)
+from synapse.storage.data_stores.main.room import RoomSortOrder
+from synapse.types import RoomAlias, RoomID, UserID, create_requester
+from synapse.util.async_helpers import maybe_awaitable
+
+logger = logging.getLogger(__name__)
+
+
+class ShutdownRoomRestServlet(RestServlet):
+    """Shuts down a room by removing all local users from the room and blocking
+    all future invites and joins to the room. Any local aliases will be repointed
+    to a new room created by `new_room_user_id` and kicked users will be auto
+    joined to the new room.
+    """
+
+    PATTERNS = historical_admin_path_patterns("/shutdown_room/(?P<room_id>[^/]+)")
+
+    DEFAULT_MESSAGE = (
+        "Sharing illegal content on this server is not permitted and rooms in"
+        " violation will be blocked."
+    )
+
+    def __init__(self, hs):
+        self.hs = hs
+        self.store = hs.get_datastore()
+        self.state = hs.get_state_handler()
+        self._room_creation_handler = hs.get_room_creation_handler()
+        self.event_creation_handler = hs.get_event_creation_handler()
+        self.room_member_handler = hs.get_room_member_handler()
+        self.auth = hs.get_auth()
+        self._replication = hs.get_replication_data_handler()
+
+    async def on_POST(self, request, room_id):
+        requester = await self.auth.get_user_by_req(request)
+        await assert_user_is_admin(self.auth, requester.user)
+
+        content = parse_json_object_from_request(request)
+        assert_params_in_dict(content, ["new_room_user_id"])
+        new_room_user_id = content["new_room_user_id"]
+
+        room_creator_requester = create_requester(new_room_user_id)
+
+        message = content.get("message", self.DEFAULT_MESSAGE)
+        room_name = content.get("room_name", "Content Violation Notification")
+
+        info, stream_id = await self._room_creation_handler.create_room(
+            room_creator_requester,
+            config={
+                "preset": "public_chat",
+                "name": room_name,
+                "power_level_content_override": {"users_default": -10},
+            },
+            ratelimit=False,
+        )
+        new_room_id = info["room_id"]
+
+        requester_user_id = requester.user.to_string()
+
+        logger.info(
+            "Shutting down room %r, joining to new room: %r", room_id, new_room_id
+        )
+
+        # This will work even if the room is already blocked, but that is
+        # desirable in case the first attempt at blocking the room failed below.
+        await self.store.block_room(room_id, requester_user_id)
+
+        # We now wait for the create room to come back in via replication so
+        # that we can assume that all the joins/invites have propogated before
+        # we try and auto join below.
+        #
+        # TODO: Currently the events stream is written to from master
+        await self._replication.wait_for_stream_position(
+            self.hs.config.worker.writers.events, "events", stream_id
+        )
+
+        users = await self.state.get_current_users_in_room(room_id)
+        kicked_users = []
+        failed_to_kick_users = []
+        for user_id in users:
+            if not self.hs.is_mine_id(user_id):
+                continue
+
+            logger.info("Kicking %r from %r...", user_id, room_id)
+
+            try:
+                target_requester = create_requester(user_id)
+                _, stream_id = await self.room_member_handler.update_membership(
+                    requester=target_requester,
+                    target=target_requester.user,
+                    room_id=room_id,
+                    action=Membership.LEAVE,
+                    content={},
+                    ratelimit=False,
+                    require_consent=False,
+                )
+
+                # Wait for leave to come in over replication before trying to forget.
+                await self._replication.wait_for_stream_position(
+                    self.hs.config.worker.writers.events, "events", stream_id
+                )
+
+                await self.room_member_handler.forget(target_requester.user, room_id)
+
+                await self.room_member_handler.update_membership(
+                    requester=target_requester,
+                    target=target_requester.user,
+                    room_id=new_room_id,
+                    action=Membership.JOIN,
+                    content={},
+                    ratelimit=False,
+                    require_consent=False,
+                )
+
+                kicked_users.append(user_id)
+            except Exception:
+                logger.exception(
+                    "Failed to leave old room and join new room for %r", user_id
+                )
+                failed_to_kick_users.append(user_id)
+
+        await self.event_creation_handler.create_and_send_nonmember_event(
+            room_creator_requester,
+            {
+                "type": "m.room.message",
+                "content": {"body": message, "msgtype": "m.text"},
+                "room_id": new_room_id,
+                "sender": new_room_user_id,
+            },
+            ratelimit=False,
+        )
+
+        aliases_for_room = await maybe_awaitable(
+            self.store.get_aliases_for_room(room_id)
+        )
+
+        await self.store.update_aliases_for_room(
+            room_id, new_room_id, requester_user_id
+        )
+
+        return (
+            200,
+            {
+                "kicked_users": kicked_users,
+                "failed_to_kick_users": failed_to_kick_users,
+                "local_aliases": aliases_for_room,
+                "new_room_id": new_room_id,
+            },
+        )
+
+
+class ListRoomRestServlet(RestServlet):
+    """
+    List all rooms that are known to the homeserver. Results are returned
+    in a dictionary containing room information. Supports pagination.
+    """
+
+    PATTERNS = admin_patterns("/rooms$")
+
+    def __init__(self, hs):
+        self.store = hs.get_datastore()
+        self.auth = hs.get_auth()
+        self.admin_handler = hs.get_handlers().admin_handler
+
+    async def on_GET(self, request):
+        requester = await self.auth.get_user_by_req(request)
+        await assert_user_is_admin(self.auth, requester.user)
+
+        # Extract query parameters
+        start = parse_integer(request, "from", default=0)
+        limit = parse_integer(request, "limit", default=100)
+        order_by = parse_string(request, "order_by", default=RoomSortOrder.NAME.value)
+        if order_by not in (
+            RoomSortOrder.ALPHABETICAL.value,
+            RoomSortOrder.SIZE.value,
+            RoomSortOrder.NAME.value,
+            RoomSortOrder.CANONICAL_ALIAS.value,
+            RoomSortOrder.JOINED_MEMBERS.value,
+            RoomSortOrder.JOINED_LOCAL_MEMBERS.value,
+            RoomSortOrder.VERSION.value,
+            RoomSortOrder.CREATOR.value,
+            RoomSortOrder.ENCRYPTION.value,
+            RoomSortOrder.FEDERATABLE.value,
+            RoomSortOrder.PUBLIC.value,
+            RoomSortOrder.JOIN_RULES.value,
+            RoomSortOrder.GUEST_ACCESS.value,
+            RoomSortOrder.HISTORY_VISIBILITY.value,
+            RoomSortOrder.STATE_EVENTS.value,
+        ):
+            raise SynapseError(
+                400,
+                "Unknown value for order_by: %s" % (order_by,),
+                errcode=Codes.INVALID_PARAM,
+            )
+
+        search_term = parse_string(request, "search_term")
+        if search_term == "":
+            raise SynapseError(
+                400,
+                "search_term cannot be an empty string",
+                errcode=Codes.INVALID_PARAM,
+            )
+
+        direction = parse_string(request, "dir", default="f")
+        if direction not in ("f", "b"):
+            raise SynapseError(
+                400, "Unknown direction: %s" % (direction,), errcode=Codes.INVALID_PARAM
+            )
+
+        reverse_order = True if direction == "b" else False
+
+        # Return list of rooms according to parameters
+        rooms, total_rooms = await self.store.get_rooms_paginate(
+            start, limit, order_by, reverse_order, search_term
+        )
+        response = {
+            # next_token should be opaque, so return a value the client can parse
+            "offset": start,
+            "rooms": rooms,
+            "total_rooms": total_rooms,
+        }
+
+        # Are there more rooms to paginate through after this?
+        if (start + limit) < total_rooms:
+            # There are. Calculate where the query should start from next time
+            # to get the next part of the list
+            response["next_batch"] = start + limit
+
+        # Is it possible to paginate backwards? Check if we currently have an
+        # offset
+        if start > 0:
+            if start > limit:
+                # Going back one iteration won't take us to the start.
+                # Calculate new offset
+                response["prev_batch"] = start - limit
+            else:
+                response["prev_batch"] = 0
+
+        return 200, response
+
+
+class RoomRestServlet(RestServlet):
+    """Get room details.
+
+    TODO: Add on_POST to allow room creation without joining the room
+    """
+
+    PATTERNS = admin_patterns("/rooms/(?P<room_id>[^/]+)$")
+
+    def __init__(self, hs):
+        self.hs = hs
+        self.auth = hs.get_auth()
+        self.store = hs.get_datastore()
+
+    async def on_GET(self, request, room_id):
+        await assert_requester_is_admin(self.auth, request)
+
+        ret = await self.store.get_room_with_stats(room_id)
+        if not ret:
+            raise NotFoundError("Room not found")
+
+        return 200, ret
+
+
+class JoinRoomAliasServlet(RestServlet):
+
+    PATTERNS = admin_patterns("/join/(?P<room_identifier>[^/]*)")
+
+    def __init__(self, hs):
+        self.hs = hs
+        self.auth = hs.get_auth()
+        self.room_member_handler = hs.get_room_member_handler()
+        self.admin_handler = hs.get_handlers().admin_handler
+        self.state_handler = hs.get_state_handler()
+
+    async def on_POST(self, request, room_identifier):
+        requester = await self.auth.get_user_by_req(request)
+        await assert_user_is_admin(self.auth, requester.user)
+
+        content = parse_json_object_from_request(request)
+
+        assert_params_in_dict(content, ["user_id"])
+        target_user = UserID.from_string(content["user_id"])
+
+        if not self.hs.is_mine(target_user):
+            raise SynapseError(400, "This endpoint can only be used with local users")
+
+        if not await self.admin_handler.get_user(target_user):
+            raise NotFoundError("User not found")
+
+        if RoomID.is_valid(room_identifier):
+            room_id = room_identifier
+            try:
+                remote_room_hosts = [
+                    x.decode("ascii") for x in request.args[b"server_name"]
+                ]  # type: Optional[List[str]]
+            except Exception:
+                remote_room_hosts = None
+        elif RoomAlias.is_valid(room_identifier):
+            handler = self.room_member_handler
+            room_alias = RoomAlias.from_string(room_identifier)
+            room_id, remote_room_hosts = await handler.lookup_room_alias(room_alias)
+            room_id = room_id.to_string()
+        else:
+            raise SynapseError(
+                400, "%s was not legal room ID or room alias" % (room_identifier,)
+            )
+
+        fake_requester = create_requester(target_user)
+
+        # send invite if room has "JoinRules.INVITE"
+        room_state = await self.state_handler.get_current_state(room_id)
+        join_rules_event = room_state.get((EventTypes.JoinRules, ""))
+        if join_rules_event:
+            if not (join_rules_event.content.get("join_rule") == JoinRules.PUBLIC):
+                await self.room_member_handler.update_membership(
+                    requester=requester,
+                    target=fake_requester.user,
+                    room_id=room_id,
+                    action="invite",
+                    remote_room_hosts=remote_room_hosts,
+                    ratelimit=False,
+                )
+
+        await self.room_member_handler.update_membership(
+            requester=fake_requester,
+            target=fake_requester.user,
+            room_id=room_id,
+            action="join",
+            remote_room_hosts=remote_room_hosts,
+            ratelimit=False,
+        )
+
+        return 200, {"room_id": room_id}
diff --git a/synapse/rest/admin/server_notice_servlet.py b/synapse/rest/admin/server_notice_servlet.py
index ae2cbe2e0a..6e9a874121 100644
--- a/synapse/rest/admin/server_notice_servlet.py
+++ b/synapse/rest/admin/server_notice_servlet.py
@@ -14,8 +14,6 @@
 # limitations under the License.
 import re
 
-from twisted.internet import defer
-
 from synapse.api.constants import EventTypes
 from synapse.api.errors import SynapseError
 from synapse.http.servlet import (
@@ -69,9 +67,8 @@ class SendServerNoticeServlet(RestServlet):
             self.__class__.__name__,
         )
 
-    @defer.inlineCallbacks
-    def on_POST(self, request, txn_id=None):
-        yield assert_requester_is_admin(self.auth, request)
+    async def on_POST(self, request, txn_id=None):
+        await assert_requester_is_admin(self.auth, request)
         body = parse_json_object_from_request(request)
         assert_params_in_dict(body, ("user_id", "content"))
         event_type = body.get("type", EventTypes.Message)
@@ -85,7 +82,7 @@ class SendServerNoticeServlet(RestServlet):
         if not self.hs.is_mine_id(user_id):
             raise SynapseError(400, "Server notices can only be sent to local users")
 
-        event = yield self.snm.send_notice(
+        event = await self.snm.send_notice(
             user_id=body["user_id"],
             type=event_type,
             state_key=state_key,
diff --git a/synapse/rest/admin/users.py b/synapse/rest/admin/users.py
index 9720a3bab0..fefc8f71fa 100644
--- a/synapse/rest/admin/users.py
+++ b/synapse/rest/admin/users.py
@@ -12,19 +12,607 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+import hashlib
+import hmac
+import logging
 import re
 
-from twisted.internet import defer
+from six import text_type
+from six.moves import http_client
 
-from synapse.api.errors import SynapseError
+from synapse.api.constants import UserTypes
+from synapse.api.errors import Codes, NotFoundError, SynapseError
 from synapse.http.servlet import (
     RestServlet,
     assert_params_in_dict,
+    parse_boolean,
+    parse_integer,
     parse_json_object_from_request,
+    parse_string,
+)
+from synapse.rest.admin._base import (
+    assert_requester_is_admin,
+    assert_user_is_admin,
+    historical_admin_path_patterns,
 )
-from synapse.rest.admin import assert_requester_is_admin, assert_user_is_admin
 from synapse.types import UserID
 
+logger = logging.getLogger(__name__)
+
+
+class UsersRestServlet(RestServlet):
+    PATTERNS = historical_admin_path_patterns("/users/(?P<user_id>[^/]*)$")
+
+    def __init__(self, hs):
+        self.hs = hs
+        self.store = hs.get_datastore()
+        self.auth = hs.get_auth()
+        self.admin_handler = hs.get_handlers().admin_handler
+
+    async def on_GET(self, request, user_id):
+        target_user = UserID.from_string(user_id)
+        await assert_requester_is_admin(self.auth, request)
+
+        if not self.hs.is_mine(target_user):
+            raise SynapseError(400, "Can only users a local user")
+
+        ret = await self.store.get_users()
+
+        return 200, ret
+
+
+class UsersRestServletV2(RestServlet):
+    PATTERNS = (re.compile("^/_synapse/admin/v2/users$"),)
+
+    """Get request to list all local users.
+    This needs user to have administrator access in Synapse.
+
+    GET /_synapse/admin/v2/users?from=0&limit=10&guests=false
+
+    returns:
+        200 OK with list of users if success otherwise an error.
+
+    The parameters `from` and `limit` are required only for pagination.
+    By default, a `limit` of 100 is used.
+    The parameter `user_id` can be used to filter by user id.
+    The parameter `guests` can be used to exclude guest users.
+    The parameter `deactivated` can be used to include deactivated users.
+    """
+
+    def __init__(self, hs):
+        self.hs = hs
+        self.store = hs.get_datastore()
+        self.auth = hs.get_auth()
+        self.admin_handler = hs.get_handlers().admin_handler
+
+    async def on_GET(self, request):
+        await assert_requester_is_admin(self.auth, request)
+
+        start = parse_integer(request, "from", default=0)
+        limit = parse_integer(request, "limit", default=100)
+        user_id = parse_string(request, "user_id", default=None)
+        guests = parse_boolean(request, "guests", default=True)
+        deactivated = parse_boolean(request, "deactivated", default=False)
+
+        users, total = await self.store.get_users_paginate(
+            start, limit, user_id, guests, deactivated
+        )
+        ret = {"users": users, "total": total}
+        if len(users) >= limit:
+            ret["next_token"] = str(start + len(users))
+
+        return 200, ret
+
+
+class UserRestServletV2(RestServlet):
+    PATTERNS = (re.compile("^/_synapse/admin/v2/users/(?P<user_id>[^/]+)$"),)
+
+    """Get request to list user details.
+    This needs user to have administrator access in Synapse.
+
+    GET /_synapse/admin/v2/users/<user_id>
+
+    returns:
+        200 OK with user details if success otherwise an error.
+
+    Put request to allow an administrator to add or modify a user.
+    This needs user to have administrator access in Synapse.
+    We use PUT instead of POST since we already know the id of the user
+    object to create. POST could be used to create guests.
+
+    PUT /_synapse/admin/v2/users/<user_id>
+    {
+        "password": "secret",
+        "displayname": "User"
+    }
+
+    returns:
+        201 OK with new user object if user was created or
+        200 OK with modified user object if user was modified
+        otherwise an error.
+    """
+
+    def __init__(self, hs):
+        self.hs = hs
+        self.auth = hs.get_auth()
+        self.admin_handler = hs.get_handlers().admin_handler
+        self.store = hs.get_datastore()
+        self.auth_handler = hs.get_auth_handler()
+        self.profile_handler = hs.get_profile_handler()
+        self.set_password_handler = hs.get_set_password_handler()
+        self.deactivate_account_handler = hs.get_deactivate_account_handler()
+        self.registration_handler = hs.get_registration_handler()
+        self.pusher_pool = hs.get_pusherpool()
+
+    async def on_GET(self, request, user_id):
+        await assert_requester_is_admin(self.auth, request)
+
+        target_user = UserID.from_string(user_id)
+        if not self.hs.is_mine(target_user):
+            raise SynapseError(400, "Can only lookup local users")
+
+        ret = await self.admin_handler.get_user(target_user)
+
+        if not ret:
+            raise NotFoundError("User not found")
+
+        return 200, ret
+
+    async def on_PUT(self, request, user_id):
+        requester = await self.auth.get_user_by_req(request)
+        await assert_user_is_admin(self.auth, requester.user)
+
+        target_user = UserID.from_string(user_id)
+        body = parse_json_object_from_request(request)
+
+        if not self.hs.is_mine(target_user):
+            raise SynapseError(400, "This endpoint can only be used with local users")
+
+        user = await self.admin_handler.get_user(target_user)
+        user_id = target_user.to_string()
+
+        if user:  # modify user
+            if "displayname" in body:
+                await self.profile_handler.set_displayname(
+                    target_user, requester, body["displayname"], True
+                )
+
+            if "threepids" in body:
+                # check for required parameters for each threepid
+                for threepid in body["threepids"]:
+                    assert_params_in_dict(threepid, ["medium", "address"])
+
+                # remove old threepids from user
+                threepids = await self.store.user_get_threepids(user_id)
+                for threepid in threepids:
+                    try:
+                        await self.auth_handler.delete_threepid(
+                            user_id, threepid["medium"], threepid["address"], None
+                        )
+                    except Exception:
+                        logger.exception("Failed to remove threepids")
+                        raise SynapseError(500, "Failed to remove threepids")
+
+                # add new threepids to user
+                current_time = self.hs.get_clock().time_msec()
+                for threepid in body["threepids"]:
+                    await self.auth_handler.add_threepid(
+                        user_id, threepid["medium"], threepid["address"], current_time
+                    )
+
+            if "avatar_url" in body and type(body["avatar_url"]) == str:
+                await self.profile_handler.set_avatar_url(
+                    target_user, requester, body["avatar_url"], True
+                )
+
+            if "admin" in body:
+                set_admin_to = bool(body["admin"])
+                if set_admin_to != user["admin"]:
+                    auth_user = requester.user
+                    if target_user == auth_user and not set_admin_to:
+                        raise SynapseError(400, "You may not demote yourself.")
+
+                    await self.store.set_server_admin(target_user, set_admin_to)
+
+            if "password" in body:
+                if (
+                    not isinstance(body["password"], text_type)
+                    or len(body["password"]) > 512
+                ):
+                    raise SynapseError(400, "Invalid password")
+                else:
+                    new_password = body["password"]
+                    logout_devices = True
+
+                    new_password_hash = await self.auth_handler.hash(new_password)
+
+                    await self.set_password_handler.set_password(
+                        target_user.to_string(),
+                        new_password_hash,
+                        logout_devices,
+                        requester,
+                    )
+
+            if "deactivated" in body:
+                deactivate = body["deactivated"]
+                if not isinstance(deactivate, bool):
+                    raise SynapseError(
+                        400, "'deactivated' parameter is not of type boolean"
+                    )
+
+                if deactivate and not user["deactivated"]:
+                    await self.deactivate_account_handler.deactivate_account(
+                        target_user.to_string(), False
+                    )
+
+            user = await self.admin_handler.get_user(target_user)
+            return 200, user
+
+        else:  # create user
+            password = body.get("password")
+            password_hash = None
+            if password is not None:
+                if not isinstance(password, text_type) or len(password) > 512:
+                    raise SynapseError(400, "Invalid password")
+                password_hash = await self.auth_handler.hash(password)
+
+            admin = body.get("admin", None)
+            user_type = body.get("user_type", None)
+            displayname = body.get("displayname", None)
+            threepids = body.get("threepids", None)
+
+            if user_type is not None and user_type not in UserTypes.ALL_USER_TYPES:
+                raise SynapseError(400, "Invalid user type")
+
+            user_id = await self.registration_handler.register_user(
+                localpart=target_user.localpart,
+                password_hash=password_hash,
+                admin=bool(admin),
+                default_display_name=displayname,
+                user_type=user_type,
+                by_admin=True,
+            )
+
+            if "threepids" in body:
+                # check for required parameters for each threepid
+                for threepid in body["threepids"]:
+                    assert_params_in_dict(threepid, ["medium", "address"])
+
+                current_time = self.hs.get_clock().time_msec()
+                for threepid in body["threepids"]:
+                    await self.auth_handler.add_threepid(
+                        user_id, threepid["medium"], threepid["address"], current_time
+                    )
+                    if (
+                        self.hs.config.email_enable_notifs
+                        and self.hs.config.email_notif_for_new_users
+                    ):
+                        await self.pusher_pool.add_pusher(
+                            user_id=user_id,
+                            access_token=None,
+                            kind="email",
+                            app_id="m.email",
+                            app_display_name="Email Notifications",
+                            device_display_name=threepid["address"],
+                            pushkey=threepid["address"],
+                            lang=None,  # We don't know a user's language here
+                            data={},
+                        )
+
+            if "avatar_url" in body and type(body["avatar_url"]) == str:
+                await self.profile_handler.set_avatar_url(
+                    user_id, requester, body["avatar_url"], True
+                )
+
+            ret = await self.admin_handler.get_user(target_user)
+
+            return 201, ret
+
+
+class UserRegisterServlet(RestServlet):
+    """
+    Attributes:
+         NONCE_TIMEOUT (int): Seconds until a generated nonce won't be accepted
+         nonces (dict[str, int]): The nonces that we will accept. A dict of
+             nonce to the time it was generated, in int seconds.
+    """
+
+    PATTERNS = historical_admin_path_patterns("/register")
+    NONCE_TIMEOUT = 60
+
+    def __init__(self, hs):
+        self.auth_handler = hs.get_auth_handler()
+        self.reactor = hs.get_reactor()
+        self.nonces = {}
+        self.hs = hs
+
+    def _clear_old_nonces(self):
+        """
+        Clear out old nonces that are older than NONCE_TIMEOUT.
+        """
+        now = int(self.reactor.seconds())
+
+        for k, v in list(self.nonces.items()):
+            if now - v > self.NONCE_TIMEOUT:
+                del self.nonces[k]
+
+    def on_GET(self, request):
+        """
+        Generate a new nonce.
+        """
+        self._clear_old_nonces()
+
+        nonce = self.hs.get_secrets().token_hex(64)
+        self.nonces[nonce] = int(self.reactor.seconds())
+        return 200, {"nonce": nonce}
+
+    async def on_POST(self, request):
+        self._clear_old_nonces()
+
+        if not self.hs.config.registration_shared_secret:
+            raise SynapseError(400, "Shared secret registration is not enabled")
+
+        body = parse_json_object_from_request(request)
+
+        if "nonce" not in body:
+            raise SynapseError(400, "nonce must be specified", errcode=Codes.BAD_JSON)
+
+        nonce = body["nonce"]
+
+        if nonce not in self.nonces:
+            raise SynapseError(400, "unrecognised nonce")
+
+        # Delete the nonce, so it can't be reused, even if it's invalid
+        del self.nonces[nonce]
+
+        if "username" not in body:
+            raise SynapseError(
+                400, "username must be specified", errcode=Codes.BAD_JSON
+            )
+        else:
+            if (
+                not isinstance(body["username"], text_type)
+                or len(body["username"]) > 512
+            ):
+                raise SynapseError(400, "Invalid username")
+
+            username = body["username"].encode("utf-8")
+            if b"\x00" in username:
+                raise SynapseError(400, "Invalid username")
+
+        if "password" not in body:
+            raise SynapseError(
+                400, "password must be specified", errcode=Codes.BAD_JSON
+            )
+        else:
+            password = body["password"]
+            if not isinstance(password, text_type) or len(password) > 512:
+                raise SynapseError(400, "Invalid password")
+
+            password_bytes = password.encode("utf-8")
+            if b"\x00" in password_bytes:
+                raise SynapseError(400, "Invalid password")
+
+            password_hash = await self.auth_handler.hash(password)
+
+        admin = body.get("admin", None)
+        user_type = body.get("user_type", None)
+
+        if user_type is not None and user_type not in UserTypes.ALL_USER_TYPES:
+            raise SynapseError(400, "Invalid user type")
+
+        got_mac = body["mac"]
+
+        want_mac_builder = hmac.new(
+            key=self.hs.config.registration_shared_secret.encode(),
+            digestmod=hashlib.sha1,
+        )
+        want_mac_builder.update(nonce.encode("utf8"))
+        want_mac_builder.update(b"\x00")
+        want_mac_builder.update(username)
+        want_mac_builder.update(b"\x00")
+        want_mac_builder.update(password_bytes)
+        want_mac_builder.update(b"\x00")
+        want_mac_builder.update(b"admin" if admin else b"notadmin")
+        if user_type:
+            want_mac_builder.update(b"\x00")
+            want_mac_builder.update(user_type.encode("utf8"))
+
+        want_mac = want_mac_builder.hexdigest()
+
+        if not hmac.compare_digest(want_mac.encode("ascii"), got_mac.encode("ascii")):
+            raise SynapseError(403, "HMAC incorrect")
+
+        # Reuse the parts of RegisterRestServlet to reduce code duplication
+        from synapse.rest.client.v2_alpha.register import RegisterRestServlet
+
+        register = RegisterRestServlet(self.hs)
+
+        user_id = await register.registration_handler.register_user(
+            localpart=body["username"].lower(),
+            password_hash=password_hash,
+            admin=bool(admin),
+            user_type=user_type,
+            by_admin=True,
+        )
+
+        result = await register._create_registration_details(user_id, body)
+        return 200, result
+
+
+class WhoisRestServlet(RestServlet):
+    PATTERNS = historical_admin_path_patterns("/whois/(?P<user_id>[^/]*)")
+
+    def __init__(self, hs):
+        self.hs = hs
+        self.auth = hs.get_auth()
+        self.handlers = hs.get_handlers()
+
+    async def on_GET(self, request, user_id):
+        target_user = UserID.from_string(user_id)
+        requester = await self.auth.get_user_by_req(request)
+        auth_user = requester.user
+
+        if target_user != auth_user:
+            await assert_user_is_admin(self.auth, auth_user)
+
+        if not self.hs.is_mine(target_user):
+            raise SynapseError(400, "Can only whois a local user")
+
+        ret = await self.handlers.admin_handler.get_whois(target_user)
+
+        return 200, ret
+
+
+class DeactivateAccountRestServlet(RestServlet):
+    PATTERNS = historical_admin_path_patterns("/deactivate/(?P<target_user_id>[^/]*)")
+
+    def __init__(self, hs):
+        self._deactivate_account_handler = hs.get_deactivate_account_handler()
+        self.auth = hs.get_auth()
+
+    async def on_POST(self, request, target_user_id):
+        await assert_requester_is_admin(self.auth, request)
+        body = parse_json_object_from_request(request, allow_empty_body=True)
+        erase = body.get("erase", False)
+        if not isinstance(erase, bool):
+            raise SynapseError(
+                http_client.BAD_REQUEST,
+                "Param 'erase' must be a boolean, if given",
+                Codes.BAD_JSON,
+            )
+
+        UserID.from_string(target_user_id)
+
+        result = await self._deactivate_account_handler.deactivate_account(
+            target_user_id, erase
+        )
+        if result:
+            id_server_unbind_result = "success"
+        else:
+            id_server_unbind_result = "no-support"
+
+        return 200, {"id_server_unbind_result": id_server_unbind_result}
+
+
+class AccountValidityRenewServlet(RestServlet):
+    PATTERNS = historical_admin_path_patterns("/account_validity/validity$")
+
+    def __init__(self, hs):
+        """
+        Args:
+            hs (synapse.server.HomeServer): server
+        """
+        self.hs = hs
+        self.account_activity_handler = hs.get_account_validity_handler()
+        self.auth = hs.get_auth()
+
+    async def on_POST(self, request):
+        await assert_requester_is_admin(self.auth, request)
+
+        body = parse_json_object_from_request(request)
+
+        if "user_id" not in body:
+            raise SynapseError(400, "Missing property 'user_id' in the request body")
+
+        expiration_ts = await self.account_activity_handler.renew_account_for_user(
+            body["user_id"],
+            body.get("expiration_ts"),
+            not body.get("enable_renewal_emails", True),
+        )
+
+        res = {"expiration_ts": expiration_ts}
+        return 200, res
+
+
+class ResetPasswordRestServlet(RestServlet):
+    """Post request to allow an administrator reset password for a user.
+    This needs user to have administrator access in Synapse.
+        Example:
+            http://localhost:8008/_synapse/admin/v1/reset_password/
+            @user:to_reset_password?access_token=admin_access_token
+        JsonBodyToSend:
+            {
+                "new_password": "secret"
+            }
+        Returns:
+            200 OK with empty object if success otherwise an error.
+        """
+
+    PATTERNS = historical_admin_path_patterns(
+        "/reset_password/(?P<target_user_id>[^/]*)"
+    )
+
+    def __init__(self, hs):
+        self.store = hs.get_datastore()
+        self.hs = hs
+        self.auth = hs.get_auth()
+        self.auth_handler = hs.get_auth_handler()
+        self._set_password_handler = hs.get_set_password_handler()
+
+    async def on_POST(self, request, target_user_id):
+        """Post request to allow an administrator reset password for a user.
+        This needs user to have administrator access in Synapse.
+        """
+        requester = await self.auth.get_user_by_req(request)
+        await assert_user_is_admin(self.auth, requester.user)
+
+        UserID.from_string(target_user_id)
+
+        params = parse_json_object_from_request(request)
+        assert_params_in_dict(params, ["new_password"])
+        new_password = params["new_password"]
+        logout_devices = params.get("logout_devices", True)
+
+        new_password_hash = await self.auth_handler.hash(new_password)
+
+        await self._set_password_handler.set_password(
+            target_user_id, new_password_hash, logout_devices, requester
+        )
+        return 200, {}
+
+
+class SearchUsersRestServlet(RestServlet):
+    """Get request to search user table for specific users according to
+    search term.
+    This needs user to have administrator access in Synapse.
+        Example:
+            http://localhost:8008/_synapse/admin/v1/search_users/
+            @admin:user?access_token=admin_access_token&term=alice
+        Returns:
+            200 OK with json object {list[dict[str, Any]], count} or empty object.
+    """
+
+    PATTERNS = historical_admin_path_patterns("/search_users/(?P<target_user_id>[^/]*)")
+
+    def __init__(self, hs):
+        self.hs = hs
+        self.store = hs.get_datastore()
+        self.auth = hs.get_auth()
+        self.handlers = hs.get_handlers()
+
+    async def on_GET(self, request, target_user_id):
+        """Get request to search user table for specific users according to
+        search term.
+        This needs user to have a administrator access in Synapse.
+        """
+        await assert_requester_is_admin(self.auth, request)
+
+        target_user = UserID.from_string(target_user_id)
+
+        # To allow all users to get the users list
+        # if not is_admin and target_user != auth_user:
+        #     raise AuthError(403, "You are not a server admin")
+
+        if not self.hs.is_mine(target_user):
+            raise SynapseError(400, "Can only users a local user")
+
+        term = parse_string(request, "term", required=True)
+        logger.info("term: %s ", term)
+
+        ret = await self.handlers.store.search_users(term)
+        return 200, ret
+
 
 class UserAdminServlet(RestServlet):
     """
@@ -52,31 +640,28 @@ class UserAdminServlet(RestServlet):
                 {}
     """
 
-    PATTERNS = (re.compile("^/_synapse/admin/v1/users/(?P<user_id>@[^/]*)/admin$"),)
+    PATTERNS = (re.compile("^/_synapse/admin/v1/users/(?P<user_id>[^/]*)/admin$"),)
 
     def __init__(self, hs):
         self.hs = hs
+        self.store = hs.get_datastore()
         self.auth = hs.get_auth()
-        self.handlers = hs.get_handlers()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, user_id):
-        yield assert_requester_is_admin(self.auth, request)
+    async def on_GET(self, request, user_id):
+        await assert_requester_is_admin(self.auth, request)
 
         target_user = UserID.from_string(user_id)
 
         if not self.hs.is_mine(target_user):
             raise SynapseError(400, "Only local users can be admins of this homeserver")
 
-        is_admin = yield self.handlers.admin_handler.get_user_server_admin(target_user)
-        is_admin = bool(is_admin)
+        is_admin = await self.store.is_server_admin(target_user)
 
         return 200, {"admin": is_admin}
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, user_id):
-        requester = yield self.auth.get_user_by_req(request)
-        yield assert_user_is_admin(self.auth, requester.user)
+    async def on_PUT(self, request, user_id):
+        requester = await self.auth.get_user_by_req(request)
+        await assert_user_is_admin(self.auth, requester.user)
         auth_user = requester.user
 
         target_user = UserID.from_string(user_id)
@@ -93,8 +678,6 @@ class UserAdminServlet(RestServlet):
         if target_user == auth_user and not set_admin_to:
             raise SynapseError(400, "You may not demote yourself.")
 
-        yield self.handlers.admin_handler.set_user_server_admin(
-            target_user, set_admin_to
-        )
+        await self.store.set_server_admin(target_user, set_admin_to)
 
         return 200, {}
diff --git a/synapse/rest/client/v1/directory.py b/synapse/rest/client/v1/directory.py
index 4ea3666874..5934b1fe8b 100644
--- a/synapse/rest/client/v1/directory.py
+++ b/synapse/rest/client/v1/directory.py
@@ -16,8 +16,6 @@
 
 import logging
 
-from twisted.internet import defer
-
 from synapse.api.errors import (
     AuthError,
     Codes,
@@ -47,17 +45,15 @@ class ClientDirectoryServer(RestServlet):
         self.handlers = hs.get_handlers()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, room_alias):
+    async def on_GET(self, request, room_alias):
         room_alias = RoomAlias.from_string(room_alias)
 
         dir_handler = self.handlers.directory_handler
-        res = yield dir_handler.get_association(room_alias)
+        res = await dir_handler.get_association(room_alias)
 
         return 200, res
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, room_alias):
+    async def on_PUT(self, request, room_alias):
         room_alias = RoomAlias.from_string(room_alias)
 
         content = parse_json_object_from_request(request)
@@ -77,26 +73,25 @@ class ClientDirectoryServer(RestServlet):
 
         # TODO(erikj): Check types.
 
-        room = yield self.store.get_room(room_id)
+        room = await self.store.get_room(room_id)
         if room is None:
             raise SynapseError(400, "Room does not exist")
 
-        requester = yield self.auth.get_user_by_req(request)
+        requester = await self.auth.get_user_by_req(request)
 
-        yield self.handlers.directory_handler.create_association(
+        await self.handlers.directory_handler.create_association(
             requester, room_alias, room_id, servers
         )
 
         return 200, {}
 
-    @defer.inlineCallbacks
-    def on_DELETE(self, request, room_alias):
+    async def on_DELETE(self, request, room_alias):
         dir_handler = self.handlers.directory_handler
 
         try:
-            service = yield self.auth.get_appservice_by_req(request)
+            service = await self.auth.get_appservice_by_req(request)
             room_alias = RoomAlias.from_string(room_alias)
-            yield dir_handler.delete_appservice_association(service, room_alias)
+            await dir_handler.delete_appservice_association(service, room_alias)
             logger.info(
                 "Application service at %s deleted alias %s",
                 service.url,
@@ -107,12 +102,12 @@ class ClientDirectoryServer(RestServlet):
             # fallback to default user behaviour if they aren't an AS
             pass
 
-        requester = yield self.auth.get_user_by_req(request)
+        requester = await self.auth.get_user_by_req(request)
         user = requester.user
 
         room_alias = RoomAlias.from_string(room_alias)
 
-        yield dir_handler.delete_association(requester, room_alias)
+        await dir_handler.delete_association(requester, room_alias)
 
         logger.info(
             "User %s deleted alias %s", user.to_string(), room_alias.to_string()
@@ -130,32 +125,29 @@ class ClientDirectoryListServer(RestServlet):
         self.handlers = hs.get_handlers()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, room_id):
-        room = yield self.store.get_room(room_id)
+    async def on_GET(self, request, room_id):
+        room = await self.store.get_room(room_id)
         if room is None:
             raise NotFoundError("Unknown room")
 
         return 200, {"visibility": "public" if room["is_public"] else "private"}
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, room_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_PUT(self, request, room_id):
+        requester = await self.auth.get_user_by_req(request)
 
         content = parse_json_object_from_request(request)
         visibility = content.get("visibility", "public")
 
-        yield self.handlers.directory_handler.edit_published_room_list(
+        await self.handlers.directory_handler.edit_published_room_list(
             requester, room_id, visibility
         )
 
         return 200, {}
 
-    @defer.inlineCallbacks
-    def on_DELETE(self, request, room_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_DELETE(self, request, room_id):
+        requester = await self.auth.get_user_by_req(request)
 
-        yield self.handlers.directory_handler.edit_published_room_list(
+        await self.handlers.directory_handler.edit_published_room_list(
             requester, room_id, "private"
         )
 
@@ -181,15 +173,14 @@ class ClientAppserviceDirectoryListServer(RestServlet):
     def on_DELETE(self, request, network_id, room_id):
         return self._edit(request, network_id, room_id, "private")
 
-    @defer.inlineCallbacks
-    def _edit(self, request, network_id, room_id, visibility):
-        requester = yield self.auth.get_user_by_req(request)
+    async def _edit(self, request, network_id, room_id, visibility):
+        requester = await self.auth.get_user_by_req(request)
         if not requester.app_service:
             raise AuthError(
                 403, "Only appservices can edit the appservice published room list"
             )
 
-        yield self.handlers.directory_handler.edit_published_appservice_room_list(
+        await self.handlers.directory_handler.edit_published_appservice_room_list(
             requester.app_service.id, network_id, room_id, visibility
         )
 
diff --git a/synapse/rest/client/v1/events.py b/synapse/rest/client/v1/events.py
index 6651b4cf07..25effd0261 100644
--- a/synapse/rest/client/v1/events.py
+++ b/synapse/rest/client/v1/events.py
@@ -16,8 +16,6 @@
 """This module contains REST servlets to do with event streaming, /events."""
 import logging
 
-from twisted.internet import defer
-
 from synapse.api.errors import SynapseError
 from synapse.http.servlet import RestServlet
 from synapse.rest.client.v2_alpha._base import client_patterns
@@ -36,9 +34,8 @@ class EventStreamRestServlet(RestServlet):
         self.event_stream_handler = hs.get_event_stream_handler()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
         is_guest = requester.is_guest
         room_id = None
         if is_guest:
@@ -57,7 +54,7 @@ class EventStreamRestServlet(RestServlet):
 
         as_client_event = b"raw" not in request.args
 
-        chunk = yield self.event_stream_handler.get_stream(
+        chunk = await self.event_stream_handler.get_stream(
             requester.user.to_string(),
             pagin_config,
             timeout=timeout,
@@ -73,7 +70,6 @@ class EventStreamRestServlet(RestServlet):
         return 200, {}
 
 
-# TODO: Unit test gets, with and without auth, with different kinds of events.
 class EventRestServlet(RestServlet):
     PATTERNS = client_patterns("/events/(?P<event_id>[^/]*)$", v1=True)
 
@@ -81,16 +77,16 @@ class EventRestServlet(RestServlet):
         super(EventRestServlet, self).__init__()
         self.clock = hs.get_clock()
         self.event_handler = hs.get_event_handler()
+        self.auth = hs.get_auth()
         self._event_serializer = hs.get_event_client_serializer()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, event_id):
-        requester = yield self.auth.get_user_by_req(request)
-        event = yield self.event_handler.get_event(requester.user, None, event_id)
+    async def on_GET(self, request, event_id):
+        requester = await self.auth.get_user_by_req(request)
+        event = await self.event_handler.get_event(requester.user, None, event_id)
 
         time_now = self.clock.time_msec()
         if event:
-            event = yield self._event_serializer.serialize_event(event, time_now)
+            event = await self._event_serializer.serialize_event(event, time_now)
             return 200, event
         else:
             return 404, "Event not found."
diff --git a/synapse/rest/client/v1/initial_sync.py b/synapse/rest/client/v1/initial_sync.py
index 2da3cd7511..910b3b4eeb 100644
--- a/synapse/rest/client/v1/initial_sync.py
+++ b/synapse/rest/client/v1/initial_sync.py
@@ -13,7 +13,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.internet import defer
 
 from synapse.http.servlet import RestServlet, parse_boolean
 from synapse.rest.client.v2_alpha._base import client_patterns
@@ -29,13 +28,12 @@ class InitialSyncRestServlet(RestServlet):
         self.initial_sync_handler = hs.get_initial_sync_handler()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_GET(self, request):
+        requester = await self.auth.get_user_by_req(request)
         as_client_event = b"raw" not in request.args
         pagination_config = PaginationConfig.from_request(request)
         include_archived = parse_boolean(request, "archived", default=False)
-        content = yield self.initial_sync_handler.snapshot_all_rooms(
+        content = await self.initial_sync_handler.snapshot_all_rooms(
             user_id=requester.user.to_string(),
             pagin_config=pagination_config,
             as_client_event=as_client_event,
diff --git a/synapse/rest/client/v1/login.py b/synapse/rest/client/v1/login.py
index 25a1b67092..dceb2792fa 100644
--- a/synapse/rest/client/v1/login.py
+++ b/synapse/rest/client/v1/login.py
@@ -14,12 +14,6 @@
 # limitations under the License.
 
 import logging
-import xml.etree.ElementTree as ET
-
-from six.moves import urllib
-
-from twisted.internet import defer
-from twisted.web.client import PartialDownloadError
 
 from synapse.api.errors import Codes, LoginError, SynapseError
 from synapse.api.ratelimiting import Ratelimiter
@@ -29,9 +23,10 @@ from synapse.http.servlet import (
     parse_json_object_from_request,
     parse_string,
 )
+from synapse.http.site import SynapseRequest
 from synapse.rest.client.v2_alpha._base import client_patterns
 from synapse.rest.well_known import WellKnownBuilder
-from synapse.types import UserID, map_username_to_mxid_localpart
+from synapse.types import UserID
 from synapse.util.msisdn import phone_number_to_msisdn
 
 logger = logging.getLogger(__name__)
@@ -88,29 +83,42 @@ class LoginRestServlet(RestServlet):
         self.jwt_algorithm = hs.config.jwt_algorithm
         self.saml2_enabled = hs.config.saml2_enabled
         self.cas_enabled = hs.config.cas_enabled
+        self.oidc_enabled = hs.config.oidc_enabled
         self.auth_handler = self.hs.get_auth_handler()
         self.registration_handler = hs.get_registration_handler()
         self.handlers = hs.get_handlers()
         self._well_known_builder = WellKnownBuilder(hs)
-        self._address_ratelimiter = Ratelimiter()
+        self._address_ratelimiter = Ratelimiter(
+            clock=hs.get_clock(),
+            rate_hz=self.hs.config.rc_login_address.per_second,
+            burst_count=self.hs.config.rc_login_address.burst_count,
+        )
+        self._account_ratelimiter = Ratelimiter(
+            clock=hs.get_clock(),
+            rate_hz=self.hs.config.rc_login_account.per_second,
+            burst_count=self.hs.config.rc_login_account.burst_count,
+        )
+        self._failed_attempts_ratelimiter = Ratelimiter(
+            clock=hs.get_clock(),
+            rate_hz=self.hs.config.rc_login_failed_attempts.per_second,
+            burst_count=self.hs.config.rc_login_failed_attempts.burst_count,
+        )
 
     def on_GET(self, request):
         flows = []
         if self.jwt_enabled:
             flows.append({"type": LoginRestServlet.JWT_TYPE})
-        if self.saml2_enabled:
-            flows.append({"type": LoginRestServlet.SSO_TYPE})
-            flows.append({"type": LoginRestServlet.TOKEN_TYPE})
-        if self.cas_enabled:
-            flows.append({"type": LoginRestServlet.SSO_TYPE})
 
+        if self.cas_enabled:
             # we advertise CAS for backwards compat, though MSC1721 renamed it
             # to SSO.
             flows.append({"type": LoginRestServlet.CAS_TYPE})
 
+        if self.cas_enabled or self.saml2_enabled or self.oidc_enabled:
+            flows.append({"type": LoginRestServlet.SSO_TYPE})
             # While its valid for us to advertise this login type generally,
             # synapse currently only gives out these tokens as part of the
-            # CAS login flow.
+            # SSO login flow.
             # Generally we don't want to advertise login flows that clients
             # don't know how to implement, since they (currently) will always
             # fall back to the fallback API if they don't understand one of the
@@ -126,26 +134,19 @@ class LoginRestServlet(RestServlet):
     def on_OPTIONS(self, request):
         return 200, {}
 
-    @defer.inlineCallbacks
-    def on_POST(self, request):
-        self._address_ratelimiter.ratelimit(
-            request.getClientIP(),
-            time_now_s=self.hs.clock.time(),
-            rate_hz=self.hs.config.rc_login_address.per_second,
-            burst_count=self.hs.config.rc_login_address.burst_count,
-            update=True,
-        )
+    async def on_POST(self, request):
+        self._address_ratelimiter.ratelimit(request.getClientIP())
 
         login_submission = parse_json_object_from_request(request)
         try:
             if self.jwt_enabled and (
                 login_submission["type"] == LoginRestServlet.JWT_TYPE
             ):
-                result = yield self.do_jwt_login(login_submission)
+                result = await self.do_jwt_login(login_submission)
             elif login_submission["type"] == LoginRestServlet.TOKEN_TYPE:
-                result = yield self.do_token_login(login_submission)
+                result = await self.do_token_login(login_submission)
             else:
-                result = yield self._do_other_login(login_submission)
+                result = await self._do_other_login(login_submission)
         except KeyError:
             raise SynapseError(400, "Missing JSON keys.")
 
@@ -154,8 +155,7 @@ class LoginRestServlet(RestServlet):
             result["well_known"] = well_known_data
         return 200, result
 
-    @defer.inlineCallbacks
-    def _do_other_login(self, login_submission):
+    async def _do_other_login(self, login_submission):
         """Handle non-token/saml/jwt logins
 
         Args:
@@ -201,28 +201,43 @@ class LoginRestServlet(RestServlet):
                 # (See add_threepid in synapse/handlers/auth.py)
                 address = address.lower()
 
+            # We also apply account rate limiting using the 3PID as a key, as
+            # otherwise using 3PID bypasses the ratelimiting based on user ID.
+            self._failed_attempts_ratelimiter.ratelimit((medium, address), update=False)
+
             # Check for login providers that support 3pid login types
-            canonical_user_id, callback_3pid = (
-                yield self.auth_handler.check_password_provider_3pid(
-                    medium, address, login_submission["password"]
-                )
+            (
+                canonical_user_id,
+                callback_3pid,
+            ) = await self.auth_handler.check_password_provider_3pid(
+                medium, address, login_submission["password"]
             )
             if canonical_user_id:
                 # Authentication through password provider and 3pid succeeded
-                result = yield self._register_device_with_callback(
+
+                result = await self._complete_login(
                     canonical_user_id, login_submission, callback_3pid
                 )
                 return result
 
             # No password providers were able to handle this 3pid
             # Check local store
-            user_id = yield self.hs.get_datastore().get_user_id_by_threepid(
+            user_id = await self.hs.get_datastore().get_user_id_by_threepid(
                 medium, address
             )
             if not user_id:
-                logger.warn(
+                logger.warning(
                     "unknown 3pid identifier medium %s, address %r", medium, address
                 )
+                # We mark that we've failed to log in here, as
+                # `check_password_provider_3pid` might have returned `None` due
+                # to an incorrect password, rather than the account not
+                # existing.
+                #
+                # If it returned None but the 3PID was bound then we won't hit
+                # this code path, which is fine as then the per-user ratelimit
+                # will kick in below.
+                self._failed_attempts_ratelimiter.can_do_action((medium, address))
                 raise LoginError(403, "", errcode=Codes.FORBIDDEN)
 
             identifier = {"type": "m.id.user", "user": user_id}
@@ -234,32 +249,71 @@ class LoginRestServlet(RestServlet):
         if "user" not in identifier:
             raise SynapseError(400, "User identifier is missing 'user' key")
 
-        canonical_user_id, callback = yield self.auth_handler.validate_login(
-            identifier["user"], login_submission
+        if identifier["user"].startswith("@"):
+            qualified_user_id = identifier["user"]
+        else:
+            qualified_user_id = UserID(identifier["user"], self.hs.hostname).to_string()
+
+        # Check if we've hit the failed ratelimit (but don't update it)
+        self._failed_attempts_ratelimiter.ratelimit(
+            qualified_user_id.lower(), update=False
         )
 
-        result = yield self._register_device_with_callback(
+        try:
+            canonical_user_id, callback = await self.auth_handler.validate_login(
+                identifier["user"], login_submission
+            )
+        except LoginError:
+            # The user has failed to log in, so we need to update the rate
+            # limiter. Using `can_do_action` avoids us raising a ratelimit
+            # exception and masking the LoginError. The actual ratelimiting
+            # should have happened above.
+            self._failed_attempts_ratelimiter.can_do_action(qualified_user_id.lower())
+            raise
+
+        result = await self._complete_login(
             canonical_user_id, login_submission, callback
         )
         return result
 
-    @defer.inlineCallbacks
-    def _register_device_with_callback(self, user_id, login_submission, callback=None):
-        """ Registers a device with a given user_id. Optionally run a callback
-        function after registration has completed.
+    async def _complete_login(
+        self, user_id, login_submission, callback=None, create_non_existent_users=False
+    ):
+        """Called when we've successfully authed the user and now need to
+        actually login them in (e.g. create devices). This gets called on
+        all succesful logins.
+
+        Applies the ratelimiting for succesful login attempts against an
+        account.
 
         Args:
             user_id (str): ID of the user to register.
             login_submission (dict): Dictionary of login information.
             callback (func|None): Callback function to run after registration.
+            create_non_existent_users (bool): Whether to create the user if
+                they don't exist. Defaults to False.
 
         Returns:
             result (Dict[str,str]): Dictionary of account information after
                 successful registration.
         """
+
+        # Before we actually log them in we check if they've already logged in
+        # too often. This happens here rather than before as we don't
+        # necessarily know the user before now.
+        self._account_ratelimiter.ratelimit(user_id.lower())
+
+        if create_non_existent_users:
+            canonical_uid = await self.auth_handler.check_user_exists(user_id)
+            if not canonical_uid:
+                canonical_uid = await self.registration_handler.register_user(
+                    localpart=UserID.from_string(user_id).localpart
+                )
+            user_id = canonical_uid
+
         device_id = login_submission.get("device_id")
         initial_display_name = login_submission.get("initial_device_display_name")
-        device_id, access_token = yield self.registration_handler.register_device(
+        device_id, access_token = await self.registration_handler.register_device(
             user_id, device_id, initial_display_name
         )
 
@@ -271,23 +325,21 @@ class LoginRestServlet(RestServlet):
         }
 
         if callback is not None:
-            yield callback(result)
+            await callback(result)
 
         return result
 
-    @defer.inlineCallbacks
-    def do_token_login(self, login_submission):
+    async def do_token_login(self, login_submission):
         token = login_submission["token"]
         auth_handler = self.auth_handler
-        user_id = (
-            yield auth_handler.validate_short_term_login_token_and_get_user_id(token)
+        user_id = await auth_handler.validate_short_term_login_token_and_get_user_id(
+            token
         )
 
-        result = yield self._register_device_with_callback(user_id, login_submission)
+        result = await self._complete_login(user_id, login_submission)
         return result
 
-    @defer.inlineCallbacks
-    def do_jwt_login(self, login_submission):
+    async def do_jwt_login(self, login_submission):
         token = login_submission.get("token", None)
         if token is None:
             raise LoginError(
@@ -311,15 +363,8 @@ class LoginRestServlet(RestServlet):
             raise LoginError(401, "Invalid JWT", errcode=Codes.UNAUTHORIZED)
 
         user_id = UserID(user, self.hs.hostname).to_string()
-
-        registered_user_id = yield self.auth_handler.check_user_exists(user_id)
-        if not registered_user_id:
-            registered_user_id = yield self.registration_handler.register_user(
-                localpart=user
-            )
-
-        result = yield self._register_device_with_callback(
-            registered_user_id, login_submission
+        result = await self._complete_login(
+            user_id, login_submission, create_non_existent_users=True
         )
         return result
 
@@ -329,24 +374,27 @@ class BaseSSORedirectServlet(RestServlet):
 
     PATTERNS = client_patterns("/login/(cas|sso)/redirect", v1=True)
 
-    def on_GET(self, request):
+    async def on_GET(self, request: SynapseRequest):
         args = request.args
         if b"redirectUrl" not in args:
             return 400, "Redirect URL not specified for SSO auth"
         client_redirect_url = args[b"redirectUrl"][0]
-        sso_url = self.get_sso_url(client_redirect_url)
+        sso_url = await self.get_sso_url(request, client_redirect_url)
         request.redirect(sso_url)
         finish_request(request)
 
-    def get_sso_url(self, client_redirect_url):
+    async def get_sso_url(
+        self, request: SynapseRequest, client_redirect_url: bytes
+    ) -> bytes:
         """Get the URL to redirect to, to perform SSO auth
 
         Args:
-            client_redirect_url (bytes): the URL that we should redirect the
+            request: The client request to redirect.
+            client_redirect_url: the URL that we should redirect the
                 client to when everything is done
 
         Returns:
-            bytes: URL to redirect to
+            URL to redirect to
         """
         # to be implemented by subclasses
         raise NotImplementedError()
@@ -354,19 +402,14 @@ class BaseSSORedirectServlet(RestServlet):
 
 class CasRedirectServlet(BaseSSORedirectServlet):
     def __init__(self, hs):
-        super(CasRedirectServlet, self).__init__()
-        self.cas_server_url = hs.config.cas_server_url.encode("ascii")
-        self.cas_service_url = hs.config.cas_service_url.encode("ascii")
+        self._cas_handler = hs.get_cas_handler()
 
-    def get_sso_url(self, client_redirect_url):
-        client_redirect_url_param = urllib.parse.urlencode(
-            {b"redirectUrl": client_redirect_url}
+    async def get_sso_url(
+        self, request: SynapseRequest, client_redirect_url: bytes
+    ) -> bytes:
+        return self._cas_handler.get_redirect_url(
+            {"redirectUrl": client_redirect_url}
         ).encode("ascii")
-        hs_redirect_url = self.cas_service_url + b"/_matrix/client/r0/login/cas/ticket"
-        service_param = urllib.parse.urlencode(
-            {b"service": b"%s?%s" % (hs_redirect_url, client_redirect_url_param)}
-        ).encode("ascii")
-        return b"%s/login?%s" % (self.cas_server_url, service_param)
 
 
 class CasTicketServlet(RestServlet):
@@ -374,80 +417,25 @@ class CasTicketServlet(RestServlet):
 
     def __init__(self, hs):
         super(CasTicketServlet, self).__init__()
-        self.cas_server_url = hs.config.cas_server_url
-        self.cas_service_url = hs.config.cas_service_url
-        self.cas_required_attributes = hs.config.cas_required_attributes
-        self._sso_auth_handler = SSOAuthHandler(hs)
-        self._http_client = hs.get_simple_http_client()
-
-    @defer.inlineCallbacks
-    def on_GET(self, request):
-        client_redirect_url = parse_string(request, "redirectUrl", required=True)
-        uri = self.cas_server_url + "/proxyValidate"
-        args = {
-            "ticket": parse_string(request, "ticket", required=True),
-            "service": self.cas_service_url,
-        }
-        try:
-            body = yield self._http_client.get_raw(uri, args)
-        except PartialDownloadError as pde:
-            # Twisted raises this error if the connection is closed,
-            # even if that's being used old-http style to signal end-of-data
-            body = pde.response
-        result = yield self.handle_cas_response(request, body, client_redirect_url)
-        return result
+        self._cas_handler = hs.get_cas_handler()
 
-    def handle_cas_response(self, request, cas_response_body, client_redirect_url):
-        user, attributes = self.parse_cas_response(cas_response_body)
+    async def on_GET(self, request: SynapseRequest) -> None:
+        client_redirect_url = parse_string(request, "redirectUrl")
+        ticket = parse_string(request, "ticket", required=True)
 
-        for required_attribute, required_value in self.cas_required_attributes.items():
-            # If required attribute was not in CAS Response - Forbidden
-            if required_attribute not in attributes:
-                raise LoginError(401, "Unauthorized", errcode=Codes.UNAUTHORIZED)
+        # Maybe get a session ID (if this ticket is from user interactive
+        # authentication).
+        session = parse_string(request, "session")
 
-            # Also need to check value
-            if required_value is not None:
-                actual_value = attributes[required_attribute]
-                # If required attribute value does not match expected - Forbidden
-                if required_value != actual_value:
-                    raise LoginError(401, "Unauthorized", errcode=Codes.UNAUTHORIZED)
+        # Either client_redirect_url or session must be provided.
+        if not client_redirect_url and not session:
+            message = "Missing string query parameter redirectUrl or session"
+            raise SynapseError(400, message, errcode=Codes.MISSING_PARAM)
 
-        return self._sso_auth_handler.on_successful_auth(
-            user, request, client_redirect_url
+        await self._cas_handler.handle_ticket(
+            request, ticket, client_redirect_url, session
         )
 
-    def parse_cas_response(self, cas_response_body):
-        user = None
-        attributes = {}
-        try:
-            root = ET.fromstring(cas_response_body)
-            if not root.tag.endswith("serviceResponse"):
-                raise Exception("root of CAS response is not serviceResponse")
-            success = root[0].tag.endswith("authenticationSuccess")
-            for child in root[0]:
-                if child.tag.endswith("user"):
-                    user = child.text
-                if child.tag.endswith("attributes"):
-                    for attribute in child:
-                        # ElementTree library expands the namespace in
-                        # attribute tags to the full URL of the namespace.
-                        # We don't care about namespace here and it will always
-                        # be encased in curly braces, so we remove them.
-                        tag = attribute.tag
-                        if "}" in tag:
-                            tag = tag.split("}")[1]
-                        attributes[tag] = attribute.text
-            if user is None:
-                raise Exception("CAS response does not contain user")
-        except Exception:
-            logger.error("Error parsing CAS response", exc_info=1)
-            raise LoginError(401, "Invalid CAS response", errcode=Codes.UNAUTHORIZED)
-        if not success:
-            raise LoginError(
-                401, "Unsuccessful CAS response", errcode=Codes.UNAUTHORIZED
-            )
-        return user, attributes
-
 
 class SAMLRedirectServlet(BaseSSORedirectServlet):
     PATTERNS = client_patterns("/login/sso/redirect", v1=True)
@@ -455,74 +443,26 @@ class SAMLRedirectServlet(BaseSSORedirectServlet):
     def __init__(self, hs):
         self._saml_handler = hs.get_saml_handler()
 
-    def get_sso_url(self, client_redirect_url):
+    async def get_sso_url(
+        self, request: SynapseRequest, client_redirect_url: bytes
+    ) -> bytes:
         return self._saml_handler.handle_redirect_request(client_redirect_url)
 
 
-class SSOAuthHandler(object):
-    """
-    Utility class for Resources and Servlets which handle the response from a SSO
-    service
+class OIDCRedirectServlet(BaseSSORedirectServlet):
+    """Implementation for /login/sso/redirect for the OIDC login flow."""
 
-    Args:
-        hs (synapse.server.HomeServer)
-    """
+    PATTERNS = client_patterns("/login/sso/redirect", v1=True)
 
     def __init__(self, hs):
-        self._hostname = hs.hostname
-        self._auth_handler = hs.get_auth_handler()
-        self._registration_handler = hs.get_registration_handler()
-        self._macaroon_gen = hs.get_macaroon_generator()
-
-    @defer.inlineCallbacks
-    def on_successful_auth(
-        self, username, request, client_redirect_url, user_display_name=None
-    ):
-        """Called once the user has successfully authenticated with the SSO.
-
-        Registers the user if necessary, and then returns a redirect (with
-        a login token) to the client.
-
-        Args:
-            username (unicode|bytes): the remote user id. We'll map this onto
-                something sane for a MXID localpath.
-
-            request (SynapseRequest): the incoming request from the browser. We'll
-                respond to it with a redirect.
-
-            client_redirect_url (unicode): the redirect_url the client gave us when
-                it first started the process.
-
-            user_display_name (unicode|None): if set, and we have to register a new user,
-                we will set their displayname to this.
+        self._oidc_handler = hs.get_oidc_handler()
 
-        Returns:
-            Deferred[none]: Completes once we have handled the request.
-        """
-        localpart = map_username_to_mxid_localpart(username)
-        user_id = UserID(localpart, self._hostname).to_string()
-        registered_user_id = yield self._auth_handler.check_user_exists(user_id)
-        if not registered_user_id:
-            registered_user_id = yield self._registration_handler.register_user(
-                localpart=localpart, default_display_name=user_display_name
-            )
-
-        login_token = self._macaroon_gen.generate_short_term_login_token(
-            registered_user_id
+    async def get_sso_url(
+        self, request: SynapseRequest, client_redirect_url: bytes
+    ) -> bytes:
+        return await self._oidc_handler.handle_redirect_request(
+            request, client_redirect_url
         )
-        redirect_url = self._add_login_token_to_redirect_url(
-            client_redirect_url, login_token
-        )
-        request.redirect(redirect_url)
-        finish_request(request)
-
-    @staticmethod
-    def _add_login_token_to_redirect_url(url, token):
-        url_parts = list(urllib.parse.urlparse(url))
-        query = dict(urllib.parse.parse_qsl(url_parts[4]))
-        query.update({"loginToken": token})
-        url_parts[4] = urllib.parse.urlencode(query)
-        return urllib.parse.urlunparse(url_parts)
 
 
 def register_servlets(hs, http_server):
@@ -532,3 +472,5 @@ def register_servlets(hs, http_server):
         CasTicketServlet(hs).register(http_server)
     elif hs.config.saml2_enabled:
         SAMLRedirectServlet(hs).register(http_server)
+    elif hs.config.oidc_enabled:
+        OIDCRedirectServlet(hs).register(http_server)
diff --git a/synapse/rest/client/v1/logout.py b/synapse/rest/client/v1/logout.py
index 4785a34d75..b0c30b65be 100644
--- a/synapse/rest/client/v1/logout.py
+++ b/synapse/rest/client/v1/logout.py
@@ -15,8 +15,6 @@
 
 import logging
 
-from twisted.internet import defer
-
 from synapse.http.servlet import RestServlet
 from synapse.rest.client.v2_alpha._base import client_patterns
 
@@ -35,17 +33,16 @@ class LogoutRestServlet(RestServlet):
     def on_OPTIONS(self, request):
         return 200, {}
 
-    @defer.inlineCallbacks
-    def on_POST(self, request):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_POST(self, request):
+        requester = await self.auth.get_user_by_req(request, allow_expired=True)
 
         if requester.device_id is None:
-            # the acccess token wasn't associated with a device.
+            # The access token wasn't associated with a device.
             # Just delete the access token
             access_token = self.auth.get_access_token_from_request(request)
-            yield self._auth_handler.delete_access_token(access_token)
+            await self._auth_handler.delete_access_token(access_token)
         else:
-            yield self._device_handler.delete_device(
+            await self._device_handler.delete_device(
                 requester.user.to_string(), requester.device_id
             )
 
@@ -64,17 +61,16 @@ class LogoutAllRestServlet(RestServlet):
     def on_OPTIONS(self, request):
         return 200, {}
 
-    @defer.inlineCallbacks
-    def on_POST(self, request):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_POST(self, request):
+        requester = await self.auth.get_user_by_req(request, allow_expired=True)
         user_id = requester.user.to_string()
 
         # first delete all of the user's devices
-        yield self._device_handler.delete_all_devices_for_user(user_id)
+        await self._device_handler.delete_all_devices_for_user(user_id)
 
         # .. and then delete any access tokens which weren't associated with
         # devices.
-        yield self._auth_handler.delete_access_tokens_for_user(user_id)
+        await self._auth_handler.delete_access_tokens_for_user(user_id)
         return 200, {}
 
 
diff --git a/synapse/rest/client/v1/presence.py b/synapse/rest/client/v1/presence.py
index 0153525cef..eec16f8ad8 100644
--- a/synapse/rest/client/v1/presence.py
+++ b/synapse/rest/client/v1/presence.py
@@ -19,8 +19,6 @@ import logging
 
 from six import string_types
 
-from twisted.internet import defer
-
 from synapse.api.errors import AuthError, SynapseError
 from synapse.handlers.presence import format_user_presence_state
 from synapse.http.servlet import RestServlet, parse_json_object_from_request
@@ -40,27 +38,25 @@ class PresenceStatusRestServlet(RestServlet):
         self.clock = hs.get_clock()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, user_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_GET(self, request, user_id):
+        requester = await self.auth.get_user_by_req(request)
         user = UserID.from_string(user_id)
 
         if requester.user != user:
-            allowed = yield self.presence_handler.is_visible(
+            allowed = await self.presence_handler.is_visible(
                 observed_user=user, observer_user=requester.user
             )
 
             if not allowed:
                 raise AuthError(403, "You are not allowed to see their presence.")
 
-        state = yield self.presence_handler.get_state(target_user=user)
+        state = await self.presence_handler.get_state(target_user=user)
         state = format_user_presence_state(state, self.clock.time_msec())
 
         return 200, state
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, user_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_PUT(self, request, user_id):
+        requester = await self.auth.get_user_by_req(request)
         user = UserID.from_string(user_id)
 
         if requester.user != user:
@@ -86,7 +82,7 @@ class PresenceStatusRestServlet(RestServlet):
             raise SynapseError(400, "Unable to parse state")
 
         if self.hs.config.use_presence:
-            yield self.presence_handler.set_state(user, state)
+            await self.presence_handler.set_state(user, state)
 
         return 200, {}
 
diff --git a/synapse/rest/client/v1/profile.py b/synapse/rest/client/v1/profile.py
index bbce2e2b71..e7fe50ed72 100644
--- a/synapse/rest/client/v1/profile.py
+++ b/synapse/rest/client/v1/profile.py
@@ -14,8 +14,8 @@
 # limitations under the License.
 
 """ This module contains REST servlets to do with profile: /profile/<paths> """
-from twisted.internet import defer
 
+from synapse.api.errors import Codes, SynapseError
 from synapse.http.servlet import RestServlet, parse_json_object_from_request
 from synapse.rest.client.v2_alpha._base import client_patterns
 from synapse.types import UserID
@@ -30,19 +30,18 @@ class ProfileDisplaynameRestServlet(RestServlet):
         self.profile_handler = hs.get_profile_handler()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, user_id):
+    async def on_GET(self, request, user_id):
         requester_user = None
 
         if self.hs.config.require_auth_for_profile_requests:
-            requester = yield self.auth.get_user_by_req(request)
+            requester = await self.auth.get_user_by_req(request)
             requester_user = requester.user
 
         user = UserID.from_string(user_id)
 
-        yield self.profile_handler.check_profile_query_allowed(user, requester_user)
+        await self.profile_handler.check_profile_query_allowed(user, requester_user)
 
-        displayname = yield self.profile_handler.get_displayname(user)
+        displayname = await self.profile_handler.get_displayname(user)
 
         ret = {}
         if displayname is not None:
@@ -50,11 +49,10 @@ class ProfileDisplaynameRestServlet(RestServlet):
 
         return 200, ret
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, user_id):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_PUT(self, request, user_id):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
         user = UserID.from_string(user_id)
-        is_admin = yield self.auth.is_server_admin(requester.user)
+        is_admin = await self.auth.is_server_admin(requester.user)
 
         content = parse_json_object_from_request(request)
 
@@ -63,7 +61,7 @@ class ProfileDisplaynameRestServlet(RestServlet):
         except Exception:
             return 400, "Unable to parse name"
 
-        yield self.profile_handler.set_displayname(user, requester, new_name, is_admin)
+        await self.profile_handler.set_displayname(user, requester, new_name, is_admin)
 
         return 200, {}
 
@@ -80,19 +78,18 @@ class ProfileAvatarURLRestServlet(RestServlet):
         self.profile_handler = hs.get_profile_handler()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, user_id):
+    async def on_GET(self, request, user_id):
         requester_user = None
 
         if self.hs.config.require_auth_for_profile_requests:
-            requester = yield self.auth.get_user_by_req(request)
+            requester = await self.auth.get_user_by_req(request)
             requester_user = requester.user
 
         user = UserID.from_string(user_id)
 
-        yield self.profile_handler.check_profile_query_allowed(user, requester_user)
+        await self.profile_handler.check_profile_query_allowed(user, requester_user)
 
-        avatar_url = yield self.profile_handler.get_avatar_url(user)
+        avatar_url = await self.profile_handler.get_avatar_url(user)
 
         ret = {}
         if avatar_url is not None:
@@ -100,19 +97,22 @@ class ProfileAvatarURLRestServlet(RestServlet):
 
         return 200, ret
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, user_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_PUT(self, request, user_id):
+        requester = await self.auth.get_user_by_req(request)
         user = UserID.from_string(user_id)
-        is_admin = yield self.auth.is_server_admin(requester.user)
+        is_admin = await self.auth.is_server_admin(requester.user)
 
         content = parse_json_object_from_request(request)
         try:
-            new_name = content["avatar_url"]
-        except Exception:
-            return 400, "Unable to parse name"
+            new_avatar_url = content["avatar_url"]
+        except KeyError:
+            raise SynapseError(
+                400, "Missing key 'avatar_url'", errcode=Codes.MISSING_PARAM
+            )
 
-        yield self.profile_handler.set_avatar_url(user, requester, new_name, is_admin)
+        await self.profile_handler.set_avatar_url(
+            user, requester, new_avatar_url, is_admin
+        )
 
         return 200, {}
 
@@ -129,20 +129,19 @@ class ProfileRestServlet(RestServlet):
         self.profile_handler = hs.get_profile_handler()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, user_id):
+    async def on_GET(self, request, user_id):
         requester_user = None
 
         if self.hs.config.require_auth_for_profile_requests:
-            requester = yield self.auth.get_user_by_req(request)
+            requester = await self.auth.get_user_by_req(request)
             requester_user = requester.user
 
         user = UserID.from_string(user_id)
 
-        yield self.profile_handler.check_profile_query_allowed(user, requester_user)
+        await self.profile_handler.check_profile_query_allowed(user, requester_user)
 
-        displayname = yield self.profile_handler.get_displayname(user)
-        avatar_url = yield self.profile_handler.get_avatar_url(user)
+        displayname = await self.profile_handler.get_displayname(user)
+        avatar_url = await self.profile_handler.get_avatar_url(user)
 
         ret = {}
         if displayname is not None:
diff --git a/synapse/rest/client/v1/push_rule.py b/synapse/rest/client/v1/push_rule.py
index 9f8c3d09e3..9fd4908136 100644
--- a/synapse/rest/client/v1/push_rule.py
+++ b/synapse/rest/client/v1/push_rule.py
@@ -13,7 +13,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.internet import defer
 
 from synapse.api.errors import (
     NotFoundError,
@@ -46,18 +45,17 @@ class PushRuleRestServlet(RestServlet):
         self.notifier = hs.get_notifier()
         self._is_worker = hs.config.worker_app is not None
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, path):
+    async def on_PUT(self, request, path):
         if self._is_worker:
             raise Exception("Cannot handle PUT /push_rules on worker")
 
-        spec = _rule_spec_from_path([x for x in path.split("/")])
+        spec = _rule_spec_from_path(path.split("/"))
         try:
             priority_class = _priority_class_from_spec(spec)
         except InvalidRuleException as e:
             raise SynapseError(400, str(e))
 
-        requester = yield self.auth.get_user_by_req(request)
+        requester = await self.auth.get_user_by_req(request)
 
         if "/" in spec["rule_id"] or "\\" in spec["rule_id"]:
             raise SynapseError(400, "rule_id may not contain slashes")
@@ -67,7 +65,7 @@ class PushRuleRestServlet(RestServlet):
         user_id = requester.user.to_string()
 
         if "attr" in spec:
-            yield self.set_rule_attr(user_id, spec, content)
+            await self.set_rule_attr(user_id, spec, content)
             self.notify_user(user_id)
             return 200, {}
 
@@ -91,7 +89,7 @@ class PushRuleRestServlet(RestServlet):
             after = _namespaced_rule_id(spec, after)
 
         try:
-            yield self.store.add_push_rule(
+            await self.store.add_push_rule(
                 user_id=user_id,
                 rule_id=_namespaced_rule_id_from_spec(spec),
                 priority_class=priority_class,
@@ -108,20 +106,19 @@ class PushRuleRestServlet(RestServlet):
 
         return 200, {}
 
-    @defer.inlineCallbacks
-    def on_DELETE(self, request, path):
+    async def on_DELETE(self, request, path):
         if self._is_worker:
             raise Exception("Cannot handle DELETE /push_rules on worker")
 
-        spec = _rule_spec_from_path([x for x in path.split("/")])
+        spec = _rule_spec_from_path(path.split("/"))
 
-        requester = yield self.auth.get_user_by_req(request)
+        requester = await self.auth.get_user_by_req(request)
         user_id = requester.user.to_string()
 
         namespaced_rule_id = _namespaced_rule_id_from_spec(spec)
 
         try:
-            yield self.store.delete_push_rule(user_id, namespaced_rule_id)
+            await self.store.delete_push_rule(user_id, namespaced_rule_id)
             self.notify_user(user_id)
             return 200, {}
         except StoreError as e:
@@ -130,19 +127,18 @@ class PushRuleRestServlet(RestServlet):
             else:
                 raise
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, path):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_GET(self, request, path):
+        requester = await self.auth.get_user_by_req(request)
         user_id = requester.user.to_string()
 
         # we build up the full structure and then decide which bits of it
         # to send which means doing unnecessary work sometimes but is
         # is probably not going to make a whole lot of difference
-        rules = yield self.store.get_push_rules_for_user(user_id)
+        rules = await self.store.get_push_rules_for_user(user_id)
 
         rules = format_push_rules_for_user(requester.user, rules)
 
-        path = [x for x in path.split("/")][1:]
+        path = path.split("/")[1:]
 
         if path == []:
             # we're a reference impl: pedantry is our job.
diff --git a/synapse/rest/client/v1/pusher.py b/synapse/rest/client/v1/pusher.py
index 41660682d9..550a2f1b44 100644
--- a/synapse/rest/client/v1/pusher.py
+++ b/synapse/rest/client/v1/pusher.py
@@ -15,8 +15,6 @@
 
 import logging
 
-from twisted.internet import defer
-
 from synapse.api.errors import Codes, StoreError, SynapseError
 from synapse.http.server import finish_request
 from synapse.http.servlet import (
@@ -30,6 +28,17 @@ from synapse.rest.client.v2_alpha._base import client_patterns
 
 logger = logging.getLogger(__name__)
 
+ALLOWED_KEYS = {
+    "app_display_name",
+    "app_id",
+    "data",
+    "device_display_name",
+    "kind",
+    "lang",
+    "profile_tag",
+    "pushkey",
+}
+
 
 class PushersRestServlet(RestServlet):
     PATTERNS = client_patterns("/pushers$", v1=True)
@@ -39,30 +48,17 @@ class PushersRestServlet(RestServlet):
         self.hs = hs
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_GET(self, request):
+        requester = await self.auth.get_user_by_req(request)
         user = requester.user
 
-        pushers = yield self.hs.get_datastore().get_pushers_by_user_id(user.to_string())
-
-        allowed_keys = [
-            "app_display_name",
-            "app_id",
-            "data",
-            "device_display_name",
-            "kind",
-            "lang",
-            "profile_tag",
-            "pushkey",
-        ]
+        pushers = await self.hs.get_datastore().get_pushers_by_user_id(user.to_string())
 
-        for p in pushers:
-            for k, v in list(p.items()):
-                if k not in allowed_keys:
-                    del p[k]
+        filtered_pushers = [
+            {k: v for k, v in p.items() if k in ALLOWED_KEYS} for p in pushers
+        ]
 
-        return 200, {"pushers": pushers}
+        return 200, {"pushers": filtered_pushers}
 
     def on_OPTIONS(self, _):
         return 200, {}
@@ -78,9 +74,8 @@ class PushersSetRestServlet(RestServlet):
         self.notifier = hs.get_notifier()
         self.pusher_pool = self.hs.get_pusherpool()
 
-    @defer.inlineCallbacks
-    def on_POST(self, request):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_POST(self, request):
+        requester = await self.auth.get_user_by_req(request)
         user = requester.user
 
         content = parse_json_object_from_request(request)
@@ -91,7 +86,7 @@ class PushersSetRestServlet(RestServlet):
             and "kind" in content
             and content["kind"] is None
         ):
-            yield self.pusher_pool.remove_pusher(
+            await self.pusher_pool.remove_pusher(
                 content["app_id"], content["pushkey"], user_id=user.to_string()
             )
             return 200, {}
@@ -117,14 +112,14 @@ class PushersSetRestServlet(RestServlet):
             append = content["append"]
 
         if not append:
-            yield self.pusher_pool.remove_pushers_by_app_id_and_pushkey_not_user(
+            await self.pusher_pool.remove_pushers_by_app_id_and_pushkey_not_user(
                 app_id=content["app_id"],
                 pushkey=content["pushkey"],
                 not_user_id=user.to_string(),
             )
 
         try:
-            yield self.pusher_pool.add_pusher(
+            await self.pusher_pool.add_pusher(
                 user_id=user.to_string(),
                 access_token=requester.access_token_id,
                 kind=content["kind"],
@@ -164,16 +159,15 @@ class PushersRemoveRestServlet(RestServlet):
         self.auth = hs.get_auth()
         self.pusher_pool = self.hs.get_pusherpool()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request):
-        requester = yield self.auth.get_user_by_req(request, rights="delete_pusher")
+    async def on_GET(self, request):
+        requester = await self.auth.get_user_by_req(request, rights="delete_pusher")
         user = requester.user
 
         app_id = parse_string(request, "app_id", required=True)
         pushkey = parse_string(request, "pushkey", required=True)
 
         try:
-            yield self.pusher_pool.remove_pusher(
+            await self.pusher_pool.remove_pusher(
                 app_id=app_id, pushkey=pushkey, user_id=user.to_string()
             )
         except StoreError as se:
diff --git a/synapse/rest/client/v1/room.py b/synapse/rest/client/v1/room.py
index a6a7b3b57e..105e0cf4d2 100644
--- a/synapse/rest/client/v1/room.py
+++ b/synapse/rest/client/v1/room.py
@@ -16,17 +16,18 @@
 
 """ This module contains REST servlets to do with rooms: /rooms/<paths> """
 import logging
+import re
+from typing import List, Optional
 
 from six.moves.urllib import parse as urlparse
 
 from canonicaljson import json
 
-from twisted.internet import defer
-
 from synapse.api.constants import EventTypes, Membership
 from synapse.api.errors import (
     AuthError,
     Codes,
+    HttpResponseException,
     InvalidClientCredentialsError,
     SynapseError,
 )
@@ -39,12 +40,17 @@ from synapse.http.servlet import (
     parse_json_object_from_request,
     parse_string,
 )
+from synapse.logging.opentracing import set_tag
 from synapse.rest.client.transactions import HttpTransactionCache
 from synapse.rest.client.v2_alpha._base import client_patterns
 from synapse.storage.state import StateFilter
 from synapse.streams.config import PaginationConfig
 from synapse.types import RoomAlias, RoomID, StreamToken, ThirdPartyInstanceID, UserID
 
+MYPY = False
+if MYPY:
+    import synapse.server
+
 logger = logging.getLogger(__name__)
 
 
@@ -81,13 +87,13 @@ class RoomCreateRestServlet(TransactionRestServlet):
         )
 
     def on_PUT(self, request, txn_id):
+        set_tag("txn_id", txn_id)
         return self.txns.fetch_or_execute_request(request, self.on_POST, request)
 
-    @defer.inlineCallbacks
-    def on_POST(self, request):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_POST(self, request):
+        requester = await self.auth.get_user_by_req(request)
 
-        info = yield self._room_creation_handler.create_room(
+        info, _ = await self._room_creation_handler.create_room(
             requester, self.get_room_config(request)
         )
 
@@ -152,15 +158,14 @@ class RoomStateEventRestServlet(TransactionRestServlet):
     def on_PUT_no_state_key(self, request, room_id, event_type):
         return self.on_PUT(request, room_id, event_type, "")
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, room_id, event_type, state_key):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request, room_id, event_type, state_key):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
         format = parse_string(
             request, "format", default="content", allowed_values=["content", "event"]
         )
 
         msg_handler = self.message_handler
-        data = yield msg_handler.get_room_data(
+        data = await msg_handler.get_room_data(
             user_id=requester.user.to_string(),
             room_id=room_id,
             event_type=event_type,
@@ -177,9 +182,11 @@ class RoomStateEventRestServlet(TransactionRestServlet):
         elif format == "content":
             return 200, data.get_dict()["content"]
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, room_id, event_type, state_key, txn_id=None):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_PUT(self, request, room_id, event_type, state_key, txn_id=None):
+        requester = await self.auth.get_user_by_req(request)
+
+        if txn_id:
+            set_tag("txn_id", txn_id)
 
         content = parse_json_object_from_request(request)
 
@@ -195,7 +202,7 @@ class RoomStateEventRestServlet(TransactionRestServlet):
 
         if event_type == EventTypes.Member:
             membership = content.get("membership", None)
-            event = yield self.room_member_handler.update_membership(
+            event_id, _ = await self.room_member_handler.update_membership(
                 requester,
                 target=UserID.from_string(state_key),
                 room_id=room_id,
@@ -203,13 +210,18 @@ class RoomStateEventRestServlet(TransactionRestServlet):
                 content=content,
             )
         else:
-            event = yield self.event_creation_handler.create_and_send_nonmember_event(
+            (
+                event,
+                _,
+            ) = await self.event_creation_handler.create_and_send_nonmember_event(
                 requester, event_dict, txn_id=txn_id
             )
+            event_id = event.event_id
 
-        ret = {}
-        if event:
-            ret = {"event_id": event.event_id}
+        ret = {}  # type: dict
+        if event_id:
+            set_tag("event_id", event_id)
+            ret = {"event_id": event_id}
         return 200, ret
 
 
@@ -225,9 +237,8 @@ class RoomSendEventRestServlet(TransactionRestServlet):
         PATTERNS = "/rooms/(?P<room_id>[^/]*)/send/(?P<event_type>[^/]*)"
         register_txn_path(self, PATTERNS, http_server, with_get=True)
 
-    @defer.inlineCallbacks
-    def on_POST(self, request, room_id, event_type, txn_id=None):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_POST(self, request, room_id, event_type, txn_id=None):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
         content = parse_json_object_from_request(request)
 
         event_dict = {
@@ -240,16 +251,19 @@ class RoomSendEventRestServlet(TransactionRestServlet):
         if b"ts" in request.args and requester.app_service:
             event_dict["origin_server_ts"] = parse_integer(request, "ts", 0)
 
-        event = yield self.event_creation_handler.create_and_send_nonmember_event(
+        event, _ = await self.event_creation_handler.create_and_send_nonmember_event(
             requester, event_dict, txn_id=txn_id
         )
 
+        set_tag("event_id", event.event_id)
         return 200, {"event_id": event.event_id}
 
     def on_GET(self, request, room_id, event_type, txn_id):
         return 200, "Not implemented"
 
     def on_PUT(self, request, room_id, event_type, txn_id):
+        set_tag("txn_id", txn_id)
+
         return self.txns.fetch_or_execute_request(
             request, self.on_POST, request, room_id, event_type, txn_id
         )
@@ -267,9 +281,8 @@ class JoinRoomAliasServlet(TransactionRestServlet):
         PATTERNS = "/join/(?P<room_identifier>[^/]*)"
         register_txn_path(self, PATTERNS, http_server)
 
-    @defer.inlineCallbacks
-    def on_POST(self, request, room_identifier, txn_id=None):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_POST(self, request, room_identifier, txn_id=None):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
 
         try:
             content = parse_json_object_from_request(request)
@@ -283,20 +296,20 @@ class JoinRoomAliasServlet(TransactionRestServlet):
             try:
                 remote_room_hosts = [
                     x.decode("ascii") for x in request.args[b"server_name"]
-                ]
+                ]  # type: Optional[List[str]]
             except Exception:
                 remote_room_hosts = None
         elif RoomAlias.is_valid(room_identifier):
             handler = self.room_member_handler
             room_alias = RoomAlias.from_string(room_identifier)
-            room_id, remote_room_hosts = yield handler.lookup_room_alias(room_alias)
+            room_id, remote_room_hosts = await handler.lookup_room_alias(room_alias)
             room_id = room_id.to_string()
         else:
             raise SynapseError(
                 400, "%s was not legal room ID or room alias" % (room_identifier,)
             )
 
-        yield self.room_member_handler.update_membership(
+        await self.room_member_handler.update_membership(
             requester=requester,
             target=requester.user,
             room_id=room_id,
@@ -310,6 +323,8 @@ class JoinRoomAliasServlet(TransactionRestServlet):
         return 200, {"room_id": room_id}
 
     def on_PUT(self, request, room_identifier, txn_id):
+        set_tag("txn_id", txn_id)
+
         return self.txns.fetch_or_execute_request(
             request, self.on_POST, request, room_identifier, txn_id
         )
@@ -324,12 +339,11 @@ class PublicRoomListRestServlet(TransactionRestServlet):
         self.hs = hs
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request):
+    async def on_GET(self, request):
         server = parse_string(request, "server", default=None)
 
         try:
-            yield self.auth.get_user_by_req(request, allow_guest=True)
+            await self.auth.get_user_by_req(request, allow_guest=True)
         except InvalidClientCredentialsError as e:
             # Option to allow servers to require auth when accessing
             # /publicRooms via CS API. This is especially helpful in private
@@ -350,26 +364,32 @@ class PublicRoomListRestServlet(TransactionRestServlet):
         limit = parse_integer(request, "limit", 0)
         since_token = parse_string(request, "since", None)
 
+        if limit == 0:
+            # zero is a special value which corresponds to no limit.
+            limit = None
+
         handler = self.hs.get_room_list_handler()
-        if server:
-            data = yield handler.get_remote_public_room_list(
-                server, limit=limit, since_token=since_token
-            )
+        if server and server != self.hs.config.server_name:
+            try:
+                data = await handler.get_remote_public_room_list(
+                    server, limit=limit, since_token=since_token
+                )
+            except HttpResponseException as e:
+                raise e.to_synapse_error()
         else:
-            data = yield handler.get_local_public_room_list(
+            data = await handler.get_local_public_room_list(
                 limit=limit, since_token=since_token
             )
 
         return 200, data
 
-    @defer.inlineCallbacks
-    def on_POST(self, request):
-        yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_POST(self, request):
+        await self.auth.get_user_by_req(request, allow_guest=True)
 
         server = parse_string(request, "server", default=None)
         content = parse_json_object_from_request(request)
 
-        limit = int(content.get("limit", 100))
+        limit = int(content.get("limit", 100))  # type: Optional[int]
         since_token = content.get("since", None)
         search_filter = content.get("filter", None)
 
@@ -387,18 +407,25 @@ class PublicRoomListRestServlet(TransactionRestServlet):
         else:
             network_tuple = ThirdPartyInstanceID.from_string(third_party_instance_id)
 
+        if limit == 0:
+            # zero is a special value which corresponds to no limit.
+            limit = None
+
         handler = self.hs.get_room_list_handler()
-        if server:
-            data = yield handler.get_remote_public_room_list(
-                server,
-                limit=limit,
-                since_token=since_token,
-                search_filter=search_filter,
-                include_all_networks=include_all_networks,
-                third_party_instance_id=third_party_instance_id,
-            )
+        if server and server != self.hs.config.server_name:
+            try:
+                data = await handler.get_remote_public_room_list(
+                    server,
+                    limit=limit,
+                    since_token=since_token,
+                    search_filter=search_filter,
+                    include_all_networks=include_all_networks,
+                    third_party_instance_id=third_party_instance_id,
+                )
+            except HttpResponseException as e:
+                raise e.to_synapse_error()
         else:
-            data = yield handler.get_local_public_room_list(
+            data = await handler.get_local_public_room_list(
                 limit=limit,
                 since_token=since_token,
                 search_filter=search_filter,
@@ -417,10 +444,9 @@ class RoomMemberListRestServlet(RestServlet):
         self.message_handler = hs.get_message_handler()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, room_id):
+    async def on_GET(self, request, room_id):
         # TODO support Pagination stream API (limit/tokens)
-        requester = yield self.auth.get_user_by_req(request)
+        requester = await self.auth.get_user_by_req(request)
         handler = self.message_handler
 
         # request the state as of a given event, as identified by a stream token,
@@ -440,7 +466,7 @@ class RoomMemberListRestServlet(RestServlet):
         membership = parse_string(request, "membership")
         not_membership = parse_string(request, "not_membership")
 
-        events = yield handler.get_state_events(
+        events = await handler.get_state_events(
             room_id=room_id,
             user_id=requester.user.to_string(),
             at_token=at_token,
@@ -469,11 +495,10 @@ class JoinedRoomMemberListRestServlet(RestServlet):
         self.message_handler = hs.get_message_handler()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, room_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_GET(self, request, room_id):
+        requester = await self.auth.get_user_by_req(request)
 
-        users_with_profile = yield self.message_handler.get_joined_members(
+        users_with_profile = await self.message_handler.get_joined_members(
             requester, room_id
         )
 
@@ -489,20 +514,24 @@ class RoomMessageListRestServlet(RestServlet):
         self.pagination_handler = hs.get_pagination_handler()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, room_id):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request, room_id):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
         pagination_config = PaginationConfig.from_request(request, default_limit=10)
         as_client_event = b"raw" not in request.args
         filter_bytes = parse_string(request, b"filter", encoding=None)
         if filter_bytes:
             filter_json = urlparse.unquote(filter_bytes.decode("UTF-8"))
-            event_filter = Filter(json.loads(filter_json))
-            if event_filter.filter_json.get("event_format", "client") == "federation":
+            event_filter = Filter(json.loads(filter_json))  # type: Optional[Filter]
+            if (
+                event_filter
+                and event_filter.filter_json.get("event_format", "client")
+                == "federation"
+            ):
                 as_client_event = False
         else:
             event_filter = None
-        msgs = yield self.pagination_handler.get_messages(
+
+        msgs = await self.pagination_handler.get_messages(
             room_id=room_id,
             requester=requester,
             pagin_config=pagination_config,
@@ -522,11 +551,10 @@ class RoomStateRestServlet(RestServlet):
         self.message_handler = hs.get_message_handler()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, room_id):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request, room_id):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
         # Get all the current state for this room
-        events = yield self.message_handler.get_state_events(
+        events = await self.message_handler.get_state_events(
             room_id=room_id,
             user_id=requester.user.to_string(),
             is_guest=requester.is_guest,
@@ -543,11 +571,10 @@ class RoomInitialSyncRestServlet(RestServlet):
         self.initial_sync_handler = hs.get_initial_sync_handler()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, room_id):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request, room_id):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
         pagination_config = PaginationConfig.from_request(request)
-        content = yield self.initial_sync_handler.room_initial_sync(
+        content = await self.initial_sync_handler.room_initial_sync(
             room_id=room_id, requester=requester, pagin_config=pagination_config
         )
         return 200, content
@@ -565,11 +592,10 @@ class RoomEventServlet(RestServlet):
         self._event_serializer = hs.get_event_client_serializer()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, room_id, event_id):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request, room_id, event_id):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
         try:
-            event = yield self.event_handler.get_event(
+            event = await self.event_handler.get_event(
                 requester.user, room_id, event_id
             )
         except AuthError:
@@ -580,7 +606,7 @@ class RoomEventServlet(RestServlet):
 
         time_now = self.clock.time_msec()
         if event:
-            event = yield self._event_serializer.serialize_event(event, time_now)
+            event = await self._event_serializer.serialize_event(event, time_now)
             return 200, event
 
         return SynapseError(404, "Event not found.", errcode=Codes.NOT_FOUND)
@@ -598,9 +624,8 @@ class RoomEventContextServlet(RestServlet):
         self._event_serializer = hs.get_event_client_serializer()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, room_id, event_id):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request, room_id, event_id):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
 
         limit = parse_integer(request, "limit", default=10)
 
@@ -608,11 +633,11 @@ class RoomEventContextServlet(RestServlet):
         filter_bytes = parse_string(request, "filter")
         if filter_bytes:
             filter_json = urlparse.unquote(filter_bytes)
-            event_filter = Filter(json.loads(filter_json))
+            event_filter = Filter(json.loads(filter_json))  # type: Optional[Filter]
         else:
             event_filter = None
 
-        results = yield self.room_context_handler.get_event_context(
+        results = await self.room_context_handler.get_event_context(
             requester.user, room_id, event_id, limit, event_filter
         )
 
@@ -620,16 +645,16 @@ class RoomEventContextServlet(RestServlet):
             raise SynapseError(404, "Event not found.", errcode=Codes.NOT_FOUND)
 
         time_now = self.clock.time_msec()
-        results["events_before"] = yield self._event_serializer.serialize_events(
+        results["events_before"] = await self._event_serializer.serialize_events(
             results["events_before"], time_now
         )
-        results["event"] = yield self._event_serializer.serialize_event(
+        results["event"] = await self._event_serializer.serialize_event(
             results["event"], time_now
         )
-        results["events_after"] = yield self._event_serializer.serialize_events(
+        results["events_after"] = await self._event_serializer.serialize_events(
             results["events_after"], time_now
         )
-        results["state"] = yield self._event_serializer.serialize_events(
+        results["state"] = await self._event_serializer.serialize_events(
             results["state"], time_now
         )
 
@@ -646,15 +671,16 @@ class RoomForgetRestServlet(TransactionRestServlet):
         PATTERNS = "/rooms/(?P<room_id>[^/]*)/forget"
         register_txn_path(self, PATTERNS, http_server)
 
-    @defer.inlineCallbacks
-    def on_POST(self, request, room_id, txn_id=None):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=False)
+    async def on_POST(self, request, room_id, txn_id=None):
+        requester = await self.auth.get_user_by_req(request, allow_guest=False)
 
-        yield self.room_member_handler.forget(user=requester.user, room_id=room_id)
+        await self.room_member_handler.forget(user=requester.user, room_id=room_id)
 
         return 200, {}
 
     def on_PUT(self, request, room_id, txn_id):
+        set_tag("txn_id", txn_id)
+
         return self.txns.fetch_or_execute_request(
             request, self.on_POST, request, room_id, txn_id
         )
@@ -675,9 +701,8 @@ class RoomMembershipRestServlet(TransactionRestServlet):
         )
         register_txn_path(self, PATTERNS, http_server)
 
-    @defer.inlineCallbacks
-    def on_POST(self, request, room_id, membership_action, txn_id=None):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_POST(self, request, room_id, membership_action, txn_id=None):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
 
         if requester.is_guest and membership_action not in {
             Membership.JOIN,
@@ -693,7 +718,7 @@ class RoomMembershipRestServlet(TransactionRestServlet):
             content = {}
 
         if membership_action == "invite" and self._has_3pid_invite_keys(content):
-            yield self.room_member_handler.do_3pid_invite(
+            await self.room_member_handler.do_3pid_invite(
                 room_id,
                 requester.user,
                 content["medium"],
@@ -711,10 +736,10 @@ class RoomMembershipRestServlet(TransactionRestServlet):
             target = UserID.from_string(content["user_id"])
 
         event_content = None
-        if "reason" in content and membership_action in ["kick", "ban"]:
+        if "reason" in content:
             event_content = {"reason": content["reason"]}
 
-        yield self.room_member_handler.update_membership(
+        await self.room_member_handler.update_membership(
             requester=requester,
             target=target,
             room_id=room_id,
@@ -738,6 +763,8 @@ class RoomMembershipRestServlet(TransactionRestServlet):
         return True
 
     def on_PUT(self, request, room_id, membership_action, txn_id):
+        set_tag("txn_id", txn_id)
+
         return self.txns.fetch_or_execute_request(
             request, self.on_POST, request, room_id, membership_action, txn_id
         )
@@ -754,12 +781,11 @@ class RoomRedactEventRestServlet(TransactionRestServlet):
         PATTERNS = "/rooms/(?P<room_id>[^/]*)/redact/(?P<event_id>[^/]*)"
         register_txn_path(self, PATTERNS, http_server)
 
-    @defer.inlineCallbacks
-    def on_POST(self, request, room_id, event_id, txn_id=None):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_POST(self, request, room_id, event_id, txn_id=None):
+        requester = await self.auth.get_user_by_req(request)
         content = parse_json_object_from_request(request)
 
-        event = yield self.event_creation_handler.create_and_send_nonmember_event(
+        event, _ = await self.event_creation_handler.create_and_send_nonmember_event(
             requester,
             {
                 "type": EventTypes.Redaction,
@@ -771,9 +797,12 @@ class RoomRedactEventRestServlet(TransactionRestServlet):
             txn_id=txn_id,
         )
 
+        set_tag("event_id", event.event_id)
         return 200, {"event_id": event.event_id}
 
     def on_PUT(self, request, room_id, event_id, txn_id):
+        set_tag("txn_id", txn_id)
+
         return self.txns.fetch_or_execute_request(
             request, self.on_POST, request, room_id, event_id, txn_id
         )
@@ -790,35 +819,57 @@ class RoomTypingRestServlet(RestServlet):
         self.typing_handler = hs.get_typing_handler()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, room_id, user_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_PUT(self, request, room_id, user_id):
+        requester = await self.auth.get_user_by_req(request)
 
         room_id = urlparse.unquote(room_id)
         target_user = UserID.from_string(urlparse.unquote(user_id))
 
         content = parse_json_object_from_request(request)
 
-        yield self.presence_handler.bump_presence_active_time(requester.user)
+        await self.presence_handler.bump_presence_active_time(requester.user)
 
         # Limit timeout to stop people from setting silly typing timeouts.
         timeout = min(content.get("timeout", 30000), 120000)
 
         if content["typing"]:
-            yield self.typing_handler.started_typing(
+            await self.typing_handler.started_typing(
                 target_user=target_user,
                 auth_user=requester.user,
                 room_id=room_id,
                 timeout=timeout,
             )
         else:
-            yield self.typing_handler.stopped_typing(
+            await self.typing_handler.stopped_typing(
                 target_user=target_user, auth_user=requester.user, room_id=room_id
             )
 
         return 200, {}
 
 
+class RoomAliasListServlet(RestServlet):
+    PATTERNS = [
+        re.compile(
+            r"^/_matrix/client/unstable/org\.matrix\.msc2432"
+            r"/rooms/(?P<room_id>[^/]*)/aliases"
+        ),
+    ]
+
+    def __init__(self, hs: "synapse.server.HomeServer"):
+        super().__init__()
+        self.auth = hs.get_auth()
+        self.directory_handler = hs.get_handlers().directory_handler
+
+    async def on_GET(self, request, room_id):
+        requester = await self.auth.get_user_by_req(request)
+
+        alias_list = await self.directory_handler.get_aliases_for_room(
+            requester, room_id
+        )
+
+        return 200, {"aliases": alias_list}
+
+
 class SearchRestServlet(RestServlet):
     PATTERNS = client_patterns("/search$", v1=True)
 
@@ -827,14 +878,13 @@ class SearchRestServlet(RestServlet):
         self.handlers = hs.get_handlers()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_POST(self, request):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_POST(self, request):
+        requester = await self.auth.get_user_by_req(request)
 
         content = parse_json_object_from_request(request)
 
         batch = parse_string(request, "next_batch")
-        results = yield self.handlers.search_handler.search(
+        results = await self.handlers.search_handler.search(
             requester.user, content, batch
         )
 
@@ -849,11 +899,10 @@ class JoinedRoomsRestServlet(RestServlet):
         self.store = hs.get_datastore()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
 
-        room_ids = yield self.store.get_rooms_for_user(requester.user.to_string())
+        room_ids = await self.store.get_rooms_for_user(requester.user.to_string())
         return 200, {"joined_rooms": list(room_ids)}
 
 
@@ -909,6 +958,7 @@ def register_servlets(hs, http_server):
     JoinedRoomsRestServlet(hs).register(http_server)
     RoomEventServlet(hs).register(http_server)
     RoomEventContextServlet(hs).register(http_server)
+    RoomAliasListServlet(hs).register(http_server)
 
 
 def register_deprecated_servlets(hs, http_server):
diff --git a/synapse/rest/client/v1/voip.py b/synapse/rest/client/v1/voip.py
index 2afdbb89e5..747d46eac2 100644
--- a/synapse/rest/client/v1/voip.py
+++ b/synapse/rest/client/v1/voip.py
@@ -17,8 +17,6 @@ import base64
 import hashlib
 import hmac
 
-from twisted.internet import defer
-
 from synapse.http.servlet import RestServlet
 from synapse.rest.client.v2_alpha._base import client_patterns
 
@@ -31,9 +29,8 @@ class VoipRestServlet(RestServlet):
         self.hs = hs
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request):
-        requester = yield self.auth.get_user_by_req(
+    async def on_GET(self, request):
+        requester = await self.auth.get_user_by_req(
             request, self.hs.config.turn_allow_guests
         )
 
diff --git a/synapse/rest/client/v2_alpha/_base.py b/synapse/rest/client/v2_alpha/_base.py
index 8250ae0ae1..bc11b4dda4 100644
--- a/synapse/rest/client/v2_alpha/_base.py
+++ b/synapse/rest/client/v2_alpha/_base.py
@@ -32,7 +32,7 @@ def client_patterns(path_regex, releases=(0,), unstable=True, v1=False):
 
     Args:
         path_regex (str): The regex string to match. This should NOT have a ^
-        as this will be prefixed.
+            as this will be prefixed.
     Returns:
         SRE_Pattern
     """
@@ -78,7 +78,7 @@ def interactive_auth_handler(orig):
             """
 
     def wrapped(*args, **kwargs):
-        res = defer.maybeDeferred(orig, *args, **kwargs)
+        res = defer.ensureDeferred(orig(*args, **kwargs))
         res.addErrback(_catch_incomplete_interactive_auth)
         return res
 
diff --git a/synapse/rest/client/v2_alpha/account.py b/synapse/rest/client/v2_alpha/account.py
index 2ea515d2f6..d4f721b6b9 100644
--- a/synapse/rest/client/v2_alpha/account.py
+++ b/synapse/rest/client/v2_alpha/account.py
@@ -18,8 +18,6 @@ import logging
 
 from six.moves import http_client
 
-from twisted.internet import defer
-
 from synapse.api.constants import LoginType
 from synapse.api.errors import Codes, SynapseError, ThreepidValidationError
 from synapse.config.emailconfig import ThreepidBehaviour
@@ -32,6 +30,7 @@ from synapse.http.servlet import (
 )
 from synapse.push.mailer import Mailer, load_jinja2_templates
 from synapse.util.msisdn import phone_number_to_msisdn
+from synapse.util.stringutils import assert_valid_client_secret, random_string
 from synapse.util.threepids import check_3pid_allowed
 
 from ._base import client_patterns, interactive_auth_handler
@@ -67,11 +66,10 @@ class EmailPasswordRequestTokenRestServlet(RestServlet):
                 template_text=template_text,
             )
 
-    @defer.inlineCallbacks
-    def on_POST(self, request):
+    async def on_POST(self, request):
         if self.config.threepid_behaviour_email == ThreepidBehaviour.OFF:
             if self.config.local_threepid_handling_disabled_due_to_email_config:
-                logger.warn(
+                logger.warning(
                     "User password resets have been disabled due to lack of email config"
                 )
             raise SynapseError(
@@ -84,6 +82,8 @@ class EmailPasswordRequestTokenRestServlet(RestServlet):
 
         # Extract params from body
         client_secret = body["client_secret"]
+        assert_valid_client_secret(client_secret)
+
         email = body["email"]
         send_attempt = body["send_attempt"]
         next_link = body.get("next_link")  # Optional param
@@ -95,25 +95,23 @@ class EmailPasswordRequestTokenRestServlet(RestServlet):
                 Codes.THREEPID_DENIED,
             )
 
-        existing_user_id = yield self.hs.get_datastore().get_user_id_by_threepid(
+        existing_user_id = await self.hs.get_datastore().get_user_id_by_threepid(
             "email", email
         )
 
         if existing_user_id is None:
+            if self.config.request_token_inhibit_3pid_errors:
+                # Make the client think the operation succeeded. See the rationale in the
+                # comments for request_token_inhibit_3pid_errors.
+                return 200, {"sid": random_string(16)}
+
             raise SynapseError(400, "Email not found", Codes.THREEPID_NOT_FOUND)
 
         if self.config.threepid_behaviour_email == ThreepidBehaviour.REMOTE:
-            # Have the configured identity server handle the request
-            if not self.hs.config.account_threepid_delegate_email:
-                logger.warn(
-                    "No upstream email account_threepid_delegate configured on the server to "
-                    "handle this request"
-                )
-                raise SynapseError(
-                    400, "Password reset by email is not supported on this homeserver"
-                )
+            assert self.hs.config.account_threepid_delegate_email
 
-            ret = yield self.identity_handler.requestEmailToken(
+            # Have the configured identity server handle the request
+            ret = await self.identity_handler.requestEmailToken(
                 self.hs.config.account_threepid_delegate_email,
                 email,
                 client_secret,
@@ -122,7 +120,7 @@ class EmailPasswordRequestTokenRestServlet(RestServlet):
             )
         else:
             # Send password reset emails from Synapse
-            sid = yield self.identity_handler.send_threepid_validation(
+            sid = await self.identity_handler.send_threepid_validation(
                 email,
                 client_secret,
                 send_attempt,
@@ -136,71 +134,11 @@ class EmailPasswordRequestTokenRestServlet(RestServlet):
         return 200, ret
 
 
-class MsisdnPasswordRequestTokenRestServlet(RestServlet):
-    PATTERNS = client_patterns("/account/password/msisdn/requestToken$")
-
-    def __init__(self, hs):
-        super(MsisdnPasswordRequestTokenRestServlet, self).__init__()
-        self.hs = hs
-        self.datastore = self.hs.get_datastore()
-        self.identity_handler = hs.get_handlers().identity_handler
-
-    @defer.inlineCallbacks
-    def on_POST(self, request):
-        body = parse_json_object_from_request(request)
-
-        assert_params_in_dict(
-            body, ["client_secret", "country", "phone_number", "send_attempt"]
-        )
-        client_secret = body["client_secret"]
-        country = body["country"]
-        phone_number = body["phone_number"]
-        send_attempt = body["send_attempt"]
-        next_link = body.get("next_link")  # Optional param
-
-        msisdn = phone_number_to_msisdn(country, phone_number)
-
-        if not check_3pid_allowed(self.hs, "msisdn", msisdn):
-            raise SynapseError(
-                403,
-                "Account phone numbers are not authorized on this server",
-                Codes.THREEPID_DENIED,
-            )
-
-        existing_user_id = yield self.datastore.get_user_id_by_threepid(
-            "msisdn", msisdn
-        )
-
-        if existing_user_id is None:
-            raise SynapseError(400, "MSISDN not found", Codes.THREEPID_NOT_FOUND)
-
-        if not self.hs.config.account_threepid_delegate_msisdn:
-            logger.warn(
-                "No upstream msisdn account_threepid_delegate configured on the server to "
-                "handle this request"
-            )
-            raise SynapseError(
-                400,
-                "Password reset by phone number is not supported on this homeserver",
-            )
-
-        ret = yield self.identity_handler.requestMsisdnToken(
-            self.hs.config.account_threepid_delegate_msisdn,
-            country,
-            phone_number,
-            client_secret,
-            send_attempt,
-            next_link,
-        )
-
-        return 200, ret
-
-
 class PasswordResetSubmitTokenServlet(RestServlet):
     """Handles 3PID validation token submission"""
 
     PATTERNS = client_patterns(
-        "/password_reset/(?P<medium>[^/]*)/submit_token/*$", releases=(), unstable=True
+        "/password_reset/(?P<medium>[^/]*)/submit_token$", releases=(), unstable=True
     )
 
     def __init__(self, hs):
@@ -214,9 +152,13 @@ class PasswordResetSubmitTokenServlet(RestServlet):
         self.config = hs.config
         self.clock = hs.get_clock()
         self.store = hs.get_datastore()
+        if self.config.threepid_behaviour_email == ThreepidBehaviour.LOCAL:
+            (self.failure_email_template,) = load_jinja2_templates(
+                self.config.email_template_dir,
+                [self.config.email_password_reset_template_failure_html],
+            )
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, medium):
+    async def on_GET(self, request, medium):
         # We currently only handle threepid token submissions for email
         if medium != "email":
             raise SynapseError(
@@ -224,7 +166,7 @@ class PasswordResetSubmitTokenServlet(RestServlet):
             )
         if self.config.threepid_behaviour_email == ThreepidBehaviour.OFF:
             if self.config.local_threepid_handling_disabled_due_to_email_config:
-                logger.warn(
+                logger.warning(
                     "Password reset emails have been disabled due to lack of an email config"
                 )
             raise SynapseError(
@@ -232,20 +174,21 @@ class PasswordResetSubmitTokenServlet(RestServlet):
             )
 
         sid = parse_string(request, "sid", required=True)
-        client_secret = parse_string(request, "client_secret", required=True)
         token = parse_string(request, "token", required=True)
+        client_secret = parse_string(request, "client_secret", required=True)
+        assert_valid_client_secret(client_secret)
 
         # Attempt to validate a 3PID session
         try:
             # Mark the session as valid
-            next_link = yield self.store.validate_threepid_session(
+            next_link = await self.store.validate_threepid_session(
                 sid, client_secret, token, self.clock.time_msec()
             )
 
             # Perform a 302 redirect if next_link is set
             if next_link:
                 if next_link.startswith("file:///"):
-                    logger.warn(
+                    logger.warning(
                         "Not redirecting to next_link as it is a local file: address"
                     )
                 else:
@@ -261,34 +204,12 @@ class PasswordResetSubmitTokenServlet(RestServlet):
             request.setResponseCode(e.code)
 
             # Show a failure page with a reason
-            html_template, = load_jinja2_templates(
-                self.config.email_template_dir,
-                [self.config.email_password_reset_template_failure_html],
-            )
-
             template_vars = {"failure_reason": e.msg}
-            html = html_template.render(**template_vars)
+            html = self.failure_email_template.render(**template_vars)
 
         request.write(html.encode("utf-8"))
         finish_request(request)
 
-    @defer.inlineCallbacks
-    def on_POST(self, request, medium):
-        if medium != "email":
-            raise SynapseError(
-                400, "This medium is currently not supported for password resets"
-            )
-
-        body = parse_json_object_from_request(request)
-        assert_params_in_dict(body, ["sid", "client_secret", "token"])
-
-        valid, _ = yield self.store.validate_threepid_session(
-            body["sid"], body["client_secret"], body["token"], self.clock.time_msec()
-        )
-        response_code = 200 if valid else 400
-
-        return response_code, {"success": valid}
-
 
 class PasswordRestServlet(RestServlet):
     PATTERNS = client_patterns("/account/password$")
@@ -299,13 +220,27 @@ class PasswordRestServlet(RestServlet):
         self.auth = hs.get_auth()
         self.auth_handler = hs.get_auth_handler()
         self.datastore = self.hs.get_datastore()
+        self.password_policy_handler = hs.get_password_policy_handler()
         self._set_password_handler = hs.get_set_password_handler()
 
     @interactive_auth_handler
-    @defer.inlineCallbacks
-    def on_POST(self, request):
+    async def on_POST(self, request):
         body = parse_json_object_from_request(request)
 
+        # we do basic sanity checks here because the auth layer will store these
+        # in sessions. Pull out the new password provided to us.
+        if "new_password" in body:
+            new_password = body.pop("new_password")
+            if not isinstance(new_password, str) or len(new_password) > 512:
+                raise SynapseError(400, "Invalid password")
+            self.password_policy_handler.validate_password(new_password)
+
+            # If the password is valid, hash it and store it back on the body.
+            # This ensures that only the hashed password is handled everywhere.
+            if "new_password_hash" in body:
+                raise SynapseError(400, "Unexpected property: new_password_hash")
+            body["new_password_hash"] = await self.auth_handler.hash(new_password)
+
         # there are two possibilities here. Either the user does not have an
         # access token, and needs to do a password reset; or they have one and
         # need to validate their identity.
@@ -317,17 +252,23 @@ class PasswordRestServlet(RestServlet):
         # In the second case, we require a password to confirm their identity.
 
         if self.auth.has_access_token(request):
-            requester = yield self.auth.get_user_by_req(request)
-            params = yield self.auth_handler.validate_user_via_ui_auth(
-                requester, body, self.hs.get_ip_from_request(request)
+            requester = await self.auth.get_user_by_req(request)
+            params = await self.auth_handler.validate_user_via_ui_auth(
+                requester,
+                request,
+                body,
+                self.hs.get_ip_from_request(request),
+                "modify your account password",
             )
             user_id = requester.user.to_string()
         else:
             requester = None
-            result, params, _ = yield self.auth_handler.check_auth(
-                [[LoginType.EMAIL_IDENTITY], [LoginType.MSISDN]],
+            result, params, _ = await self.auth_handler.check_auth(
+                [[LoginType.EMAIL_IDENTITY]],
+                request,
                 body,
                 self.hs.get_ip_from_request(request),
+                "modify your account password",
             )
 
             if LoginType.EMAIL_IDENTITY in result:
@@ -340,7 +281,7 @@ class PasswordRestServlet(RestServlet):
                     # (See add_threepid in synapse/handlers/auth.py)
                     threepid["address"] = threepid["address"].lower()
                 # if using email, we must know about the email they're authing with!
-                threepid_user_id = yield self.datastore.get_user_id_by_threepid(
+                threepid_user_id = await self.datastore.get_user_id_by_threepid(
                     threepid["medium"], threepid["address"]
                 )
                 if not threepid_user_id:
@@ -350,10 +291,13 @@ class PasswordRestServlet(RestServlet):
                 logger.error("Auth succeeded but no known type! %r", result.keys())
                 raise SynapseError(500, "", Codes.UNKNOWN)
 
-        assert_params_in_dict(params, ["new_password"])
-        new_password = params["new_password"]
+        assert_params_in_dict(params, ["new_password_hash"])
+        new_password_hash = params["new_password_hash"]
+        logout_devices = params.get("logout_devices", True)
 
-        yield self._set_password_handler.set_password(user_id, new_password, requester)
+        await self._set_password_handler.set_password(
+            user_id, new_password_hash, logout_devices, requester
+        )
 
         return 200, {}
 
@@ -372,8 +316,7 @@ class DeactivateAccountRestServlet(RestServlet):
         self._deactivate_account_handler = hs.get_deactivate_account_handler()
 
     @interactive_auth_handler
-    @defer.inlineCallbacks
-    def on_POST(self, request):
+    async def on_POST(self, request):
         body = parse_json_object_from_request(request)
         erase = body.get("erase", False)
         if not isinstance(erase, bool):
@@ -383,19 +326,23 @@ class DeactivateAccountRestServlet(RestServlet):
                 Codes.BAD_JSON,
             )
 
-        requester = yield self.auth.get_user_by_req(request)
+        requester = await self.auth.get_user_by_req(request)
 
         # allow ASes to dectivate their own users
         if requester.app_service:
-            yield self._deactivate_account_handler.deactivate_account(
+            await self._deactivate_account_handler.deactivate_account(
                 requester.user.to_string(), erase
             )
             return 200, {}
 
-        yield self.auth_handler.validate_user_via_ui_auth(
-            requester, body, self.hs.get_ip_from_request(request)
+        await self.auth_handler.validate_user_via_ui_auth(
+            requester,
+            request,
+            body,
+            self.hs.get_ip_from_request(request),
+            "deactivate your account",
         )
-        result = yield self._deactivate_account_handler.deactivate_account(
+        result = await self._deactivate_account_handler.deactivate_account(
             requester.user.to_string(), erase, id_server=body.get("id_server")
         )
         if result:
@@ -416,14 +363,37 @@ class EmailThreepidRequestTokenRestServlet(RestServlet):
         self.identity_handler = hs.get_handlers().identity_handler
         self.store = self.hs.get_datastore()
 
-    @defer.inlineCallbacks
-    def on_POST(self, request):
+        if self.config.threepid_behaviour_email == ThreepidBehaviour.LOCAL:
+            template_html, template_text = load_jinja2_templates(
+                self.config.email_template_dir,
+                [
+                    self.config.email_add_threepid_template_html,
+                    self.config.email_add_threepid_template_text,
+                ],
+                public_baseurl=self.config.public_baseurl,
+            )
+            self.mailer = Mailer(
+                hs=self.hs,
+                app_name=self.config.email_app_name,
+                template_html=template_html,
+                template_text=template_text,
+            )
+
+    async def on_POST(self, request):
+        if self.config.threepid_behaviour_email == ThreepidBehaviour.OFF:
+            if self.config.local_threepid_handling_disabled_due_to_email_config:
+                logger.warning(
+                    "Adding emails have been disabled due to lack of an email config"
+                )
+            raise SynapseError(
+                400, "Adding an email to your account is disabled on this server"
+            )
+
         body = parse_json_object_from_request(request)
-        assert_params_in_dict(
-            body, ["id_server", "client_secret", "email", "send_attempt"]
-        )
-        id_server = "https://" + body["id_server"]  # Assume https
+        assert_params_in_dict(body, ["client_secret", "email", "send_attempt"])
         client_secret = body["client_secret"]
+        assert_valid_client_secret(client_secret)
+
         email = body["email"]
         send_attempt = body["send_attempt"]
         next_link = body.get("next_link")  # Optional param
@@ -435,16 +405,42 @@ class EmailThreepidRequestTokenRestServlet(RestServlet):
                 Codes.THREEPID_DENIED,
             )
 
-        existing_user_id = yield self.store.get_user_id_by_threepid(
+        existing_user_id = await self.store.get_user_id_by_threepid(
             "email", body["email"]
         )
 
         if existing_user_id is not None:
+            if self.config.request_token_inhibit_3pid_errors:
+                # Make the client think the operation succeeded. See the rationale in the
+                # comments for request_token_inhibit_3pid_errors.
+                return 200, {"sid": random_string(16)}
+
             raise SynapseError(400, "Email is already in use", Codes.THREEPID_IN_USE)
 
-        ret = yield self.identity_handler.requestEmailToken(
-            id_server, email, client_secret, send_attempt, next_link
-        )
+        if self.config.threepid_behaviour_email == ThreepidBehaviour.REMOTE:
+            assert self.hs.config.account_threepid_delegate_email
+
+            # Have the configured identity server handle the request
+            ret = await self.identity_handler.requestEmailToken(
+                self.hs.config.account_threepid_delegate_email,
+                email,
+                client_secret,
+                send_attempt,
+                next_link,
+            )
+        else:
+            # Send threepid validation emails from Synapse
+            sid = await self.identity_handler.send_threepid_validation(
+                email,
+                client_secret,
+                send_attempt,
+                self.mailer.send_add_threepid_mail,
+                next_link,
+            )
+
+            # Wrap the session id in a JSON object
+            ret = {"sid": sid}
+
         return 200, ret
 
 
@@ -457,15 +453,14 @@ class MsisdnThreepidRequestTokenRestServlet(RestServlet):
         self.store = self.hs.get_datastore()
         self.identity_handler = hs.get_handlers().identity_handler
 
-    @defer.inlineCallbacks
-    def on_POST(self, request):
+    async def on_POST(self, request):
         body = parse_json_object_from_request(request)
         assert_params_in_dict(
-            body,
-            ["id_server", "client_secret", "country", "phone_number", "send_attempt"],
+            body, ["client_secret", "country", "phone_number", "send_attempt"]
         )
-        id_server = "https://" + body["id_server"]  # Assume https
         client_secret = body["client_secret"]
+        assert_valid_client_secret(client_secret)
+
         country = body["country"]
         phone_number = body["phone_number"]
         send_attempt = body["send_attempt"]
@@ -480,17 +475,156 @@ class MsisdnThreepidRequestTokenRestServlet(RestServlet):
                 Codes.THREEPID_DENIED,
             )
 
-        existing_user_id = yield self.store.get_user_id_by_threepid("msisdn", msisdn)
+        existing_user_id = await self.store.get_user_id_by_threepid("msisdn", msisdn)
 
         if existing_user_id is not None:
+            if self.hs.config.request_token_inhibit_3pid_errors:
+                # Make the client think the operation succeeded. See the rationale in the
+                # comments for request_token_inhibit_3pid_errors.
+                return 200, {"sid": random_string(16)}
+
             raise SynapseError(400, "MSISDN is already in use", Codes.THREEPID_IN_USE)
 
-        ret = yield self.identity_handler.requestMsisdnToken(
-            id_server, country, phone_number, client_secret, send_attempt, next_link
+        if not self.hs.config.account_threepid_delegate_msisdn:
+            logger.warning(
+                "No upstream msisdn account_threepid_delegate configured on the server to "
+                "handle this request"
+            )
+            raise SynapseError(
+                400,
+                "Adding phone numbers to user account is not supported by this homeserver",
+            )
+
+        ret = await self.identity_handler.requestMsisdnToken(
+            self.hs.config.account_threepid_delegate_msisdn,
+            country,
+            phone_number,
+            client_secret,
+            send_attempt,
+            next_link,
         )
+
         return 200, ret
 
 
+class AddThreepidEmailSubmitTokenServlet(RestServlet):
+    """Handles 3PID validation token submission for adding an email to a user's account"""
+
+    PATTERNS = client_patterns(
+        "/add_threepid/email/submit_token$", releases=(), unstable=True
+    )
+
+    def __init__(self, hs):
+        """
+        Args:
+            hs (synapse.server.HomeServer): server
+        """
+        super().__init__()
+        self.config = hs.config
+        self.clock = hs.get_clock()
+        self.store = hs.get_datastore()
+        if self.config.threepid_behaviour_email == ThreepidBehaviour.LOCAL:
+            (self.failure_email_template,) = load_jinja2_templates(
+                self.config.email_template_dir,
+                [self.config.email_add_threepid_template_failure_html],
+            )
+
+    async def on_GET(self, request):
+        if self.config.threepid_behaviour_email == ThreepidBehaviour.OFF:
+            if self.config.local_threepid_handling_disabled_due_to_email_config:
+                logger.warning(
+                    "Adding emails have been disabled due to lack of an email config"
+                )
+            raise SynapseError(
+                400, "Adding an email to your account is disabled on this server"
+            )
+        elif self.config.threepid_behaviour_email == ThreepidBehaviour.REMOTE:
+            raise SynapseError(
+                400,
+                "This homeserver is not validating threepids. Use an identity server "
+                "instead.",
+            )
+
+        sid = parse_string(request, "sid", required=True)
+        token = parse_string(request, "token", required=True)
+        client_secret = parse_string(request, "client_secret", required=True)
+        assert_valid_client_secret(client_secret)
+
+        # Attempt to validate a 3PID session
+        try:
+            # Mark the session as valid
+            next_link = await self.store.validate_threepid_session(
+                sid, client_secret, token, self.clock.time_msec()
+            )
+
+            # Perform a 302 redirect if next_link is set
+            if next_link:
+                if next_link.startswith("file:///"):
+                    logger.warning(
+                        "Not redirecting to next_link as it is a local file: address"
+                    )
+                else:
+                    request.setResponseCode(302)
+                    request.setHeader("Location", next_link)
+                    finish_request(request)
+                    return None
+
+            # Otherwise show the success template
+            html = self.config.email_add_threepid_template_success_html_content
+            request.setResponseCode(200)
+        except ThreepidValidationError as e:
+            request.setResponseCode(e.code)
+
+            # Show a failure page with a reason
+            template_vars = {"failure_reason": e.msg}
+            html = self.failure_email_template.render(**template_vars)
+
+        request.write(html.encode("utf-8"))
+        finish_request(request)
+
+
+class AddThreepidMsisdnSubmitTokenServlet(RestServlet):
+    """Handles 3PID validation token submission for adding a phone number to a user's
+    account
+    """
+
+    PATTERNS = client_patterns(
+        "/add_threepid/msisdn/submit_token$", releases=(), unstable=True
+    )
+
+    def __init__(self, hs):
+        """
+        Args:
+            hs (synapse.server.HomeServer): server
+        """
+        super().__init__()
+        self.config = hs.config
+        self.clock = hs.get_clock()
+        self.store = hs.get_datastore()
+        self.identity_handler = hs.get_handlers().identity_handler
+
+    async def on_POST(self, request):
+        if not self.config.account_threepid_delegate_msisdn:
+            raise SynapseError(
+                400,
+                "This homeserver is not validating phone numbers. Use an identity server "
+                "instead.",
+            )
+
+        body = parse_json_object_from_request(request)
+        assert_params_in_dict(body, ["client_secret", "sid", "token"])
+        assert_valid_client_secret(body["client_secret"])
+
+        # Proxy submit_token request to msisdn threepid delegate
+        response = await self.identity_handler.proxy_msisdn_submit_token(
+            self.config.account_threepid_delegate_msisdn,
+            body["client_secret"],
+            body["sid"],
+            body["token"],
+        )
+        return 200, response
+
+
 class ThreepidRestServlet(RestServlet):
     PATTERNS = client_patterns("/account/3pid$")
 
@@ -502,16 +636,21 @@ class ThreepidRestServlet(RestServlet):
         self.auth_handler = hs.get_auth_handler()
         self.datastore = self.hs.get_datastore()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_GET(self, request):
+        requester = await self.auth.get_user_by_req(request)
 
-        threepids = yield self.datastore.user_get_threepids(requester.user.to_string())
+        threepids = await self.datastore.user_get_threepids(requester.user.to_string())
 
         return 200, {"threepids": threepids}
 
-    @defer.inlineCallbacks
-    def on_POST(self, request):
+    async def on_POST(self, request):
+        if not self.hs.config.enable_3pid_changes:
+            raise SynapseError(
+                400, "3PID changes are disabled on this server", Codes.FORBIDDEN
+            )
+
+        requester = await self.auth.get_user_by_req(request)
+        user_id = requester.user.to_string()
         body = parse_json_object_from_request(request)
 
         threepid_creds = body.get("threePidCreds") or body.get("three_pid_creds")
@@ -519,34 +658,111 @@ class ThreepidRestServlet(RestServlet):
             raise SynapseError(
                 400, "Missing param three_pid_creds", Codes.MISSING_PARAM
             )
+        assert_params_in_dict(threepid_creds, ["client_secret", "sid"])
+
+        sid = threepid_creds["sid"]
+        client_secret = threepid_creds["client_secret"]
+        assert_valid_client_secret(client_secret)
+
+        validation_session = await self.identity_handler.validate_threepid_session(
+            client_secret, sid
+        )
+        if validation_session:
+            await self.auth_handler.add_threepid(
+                user_id,
+                validation_session["medium"],
+                validation_session["address"],
+                validation_session["validated_at"],
+            )
+            return 200, {}
+
+        raise SynapseError(
+            400, "No validated 3pid session found", Codes.THREEPID_AUTH_FAILED
+        )
+
+
+class ThreepidAddRestServlet(RestServlet):
+    PATTERNS = client_patterns("/account/3pid/add$", releases=(), unstable=True)
+
+    def __init__(self, hs):
+        super(ThreepidAddRestServlet, self).__init__()
+        self.hs = hs
+        self.identity_handler = hs.get_handlers().identity_handler
+        self.auth = hs.get_auth()
+        self.auth_handler = hs.get_auth_handler()
+
+    @interactive_auth_handler
+    async def on_POST(self, request):
+        if not self.hs.config.enable_3pid_changes:
+            raise SynapseError(
+                400, "3PID changes are disabled on this server", Codes.FORBIDDEN
+            )
 
-        requester = yield self.auth.get_user_by_req(request)
+        requester = await self.auth.get_user_by_req(request)
         user_id = requester.user.to_string()
+        body = parse_json_object_from_request(request)
 
-        # Specify None as the identity server to retrieve it from the request body instead
-        threepid = yield self.identity_handler.threepid_from_creds(None, threepid_creds)
+        assert_params_in_dict(body, ["client_secret", "sid"])
+        sid = body["sid"]
+        client_secret = body["client_secret"]
+        assert_valid_client_secret(client_secret)
 
-        if not threepid:
-            raise SynapseError(400, "Failed to auth 3pid", Codes.THREEPID_AUTH_FAILED)
+        await self.auth_handler.validate_user_via_ui_auth(
+            requester,
+            request,
+            body,
+            self.hs.get_ip_from_request(request),
+            "add a third-party identifier to your account",
+        )
 
-        for reqd in ["medium", "address", "validated_at"]:
-            if reqd not in threepid:
-                logger.warn("Couldn't add 3pid: invalid response from ID server")
-                raise SynapseError(500, "Invalid response from ID Server")
+        validation_session = await self.identity_handler.validate_threepid_session(
+            client_secret, sid
+        )
+        if validation_session:
+            await self.auth_handler.add_threepid(
+                user_id,
+                validation_session["medium"],
+                validation_session["address"],
+                validation_session["validated_at"],
+            )
+            return 200, {}
 
-        yield self.auth_handler.add_threepid(
-            user_id, threepid["medium"], threepid["address"], threepid["validated_at"]
+        raise SynapseError(
+            400, "No validated 3pid session found", Codes.THREEPID_AUTH_FAILED
         )
 
-        if "bind" in body and body["bind"]:
-            logger.debug("Binding threepid %s to %s", threepid, user_id)
-            yield self.identity_handler.bind_threepid(threepid_creds, user_id)
+
+class ThreepidBindRestServlet(RestServlet):
+    PATTERNS = client_patterns("/account/3pid/bind$", releases=(), unstable=True)
+
+    def __init__(self, hs):
+        super(ThreepidBindRestServlet, self).__init__()
+        self.hs = hs
+        self.identity_handler = hs.get_handlers().identity_handler
+        self.auth = hs.get_auth()
+
+    async def on_POST(self, request):
+        body = parse_json_object_from_request(request)
+
+        assert_params_in_dict(body, ["id_server", "sid", "client_secret"])
+        id_server = body["id_server"]
+        sid = body["sid"]
+        id_access_token = body.get("id_access_token")  # optional
+        client_secret = body["client_secret"]
+        assert_valid_client_secret(client_secret)
+
+        requester = await self.auth.get_user_by_req(request)
+        user_id = requester.user.to_string()
+
+        await self.identity_handler.bind_threepid(
+            client_secret, sid, user_id, id_server, id_access_token
+        )
 
         return 200, {}
 
 
 class ThreepidUnbindRestServlet(RestServlet):
-    PATTERNS = client_patterns("/account/3pid/unbind$")
+    PATTERNS = client_patterns("/account/3pid/unbind$", releases=(), unstable=True)
 
     def __init__(self, hs):
         super(ThreepidUnbindRestServlet, self).__init__()
@@ -555,12 +771,11 @@ class ThreepidUnbindRestServlet(RestServlet):
         self.auth = hs.get_auth()
         self.datastore = self.hs.get_datastore()
 
-    @defer.inlineCallbacks
-    def on_POST(self, request):
+    async def on_POST(self, request):
         """Unbind the given 3pid from a specific identity server, or identity servers that are
         known to have this 3pid bound
         """
-        requester = yield self.auth.get_user_by_req(request)
+        requester = await self.auth.get_user_by_req(request)
         body = parse_json_object_from_request(request)
         assert_params_in_dict(body, ["medium", "address"])
 
@@ -570,7 +785,7 @@ class ThreepidUnbindRestServlet(RestServlet):
 
         # Attempt to unbind the threepid from an identity server. If id_server is None, try to
         # unbind from all identity servers this threepid has been added to in the past
-        result = yield self.identity_handler.try_unbind_threepid(
+        result = await self.identity_handler.try_unbind_threepid(
             requester.user.to_string(),
             {"address": address, "medium": medium, "id_server": id_server},
         )
@@ -582,19 +797,24 @@ class ThreepidDeleteRestServlet(RestServlet):
 
     def __init__(self, hs):
         super(ThreepidDeleteRestServlet, self).__init__()
+        self.hs = hs
         self.auth = hs.get_auth()
         self.auth_handler = hs.get_auth_handler()
 
-    @defer.inlineCallbacks
-    def on_POST(self, request):
+    async def on_POST(self, request):
+        if not self.hs.config.enable_3pid_changes:
+            raise SynapseError(
+                400, "3PID changes are disabled on this server", Codes.FORBIDDEN
+            )
+
         body = parse_json_object_from_request(request)
         assert_params_in_dict(body, ["medium", "address"])
 
-        requester = yield self.auth.get_user_by_req(request)
+        requester = await self.auth.get_user_by_req(request)
         user_id = requester.user.to_string()
 
         try:
-            ret = yield self.auth_handler.delete_threepid(
+            ret = await self.auth_handler.delete_threepid(
                 user_id, body["medium"], body["address"], body.get("id_server")
             )
         except Exception:
@@ -619,22 +839,24 @@ class WhoamiRestServlet(RestServlet):
         super(WhoamiRestServlet, self).__init__()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_GET(self, request):
+        requester = await self.auth.get_user_by_req(request)
 
         return 200, {"user_id": requester.user.to_string()}
 
 
 def register_servlets(hs, http_server):
     EmailPasswordRequestTokenRestServlet(hs).register(http_server)
-    MsisdnPasswordRequestTokenRestServlet(hs).register(http_server)
     PasswordResetSubmitTokenServlet(hs).register(http_server)
     PasswordRestServlet(hs).register(http_server)
     DeactivateAccountRestServlet(hs).register(http_server)
     EmailThreepidRequestTokenRestServlet(hs).register(http_server)
     MsisdnThreepidRequestTokenRestServlet(hs).register(http_server)
+    AddThreepidEmailSubmitTokenServlet(hs).register(http_server)
+    AddThreepidMsisdnSubmitTokenServlet(hs).register(http_server)
     ThreepidRestServlet(hs).register(http_server)
+    ThreepidAddRestServlet(hs).register(http_server)
+    ThreepidBindRestServlet(hs).register(http_server)
     ThreepidUnbindRestServlet(hs).register(http_server)
     ThreepidDeleteRestServlet(hs).register(http_server)
     WhoamiRestServlet(hs).register(http_server)
diff --git a/synapse/rest/client/v2_alpha/account_data.py b/synapse/rest/client/v2_alpha/account_data.py
index f0db204ffa..c1d4cd0caf 100644
--- a/synapse/rest/client/v2_alpha/account_data.py
+++ b/synapse/rest/client/v2_alpha/account_data.py
@@ -15,8 +15,6 @@
 
 import logging
 
-from twisted.internet import defer
-
 from synapse.api.errors import AuthError, NotFoundError, SynapseError
 from synapse.http.servlet import RestServlet, parse_json_object_from_request
 
@@ -40,16 +38,19 @@ class AccountDataServlet(RestServlet):
         self.auth = hs.get_auth()
         self.store = hs.get_datastore()
         self.notifier = hs.get_notifier()
+        self._is_worker = hs.config.worker_app is not None
+
+    async def on_PUT(self, request, user_id, account_data_type):
+        if self._is_worker:
+            raise Exception("Cannot handle PUT /account_data on worker")
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, user_id, account_data_type):
-        requester = yield self.auth.get_user_by_req(request)
+        requester = await self.auth.get_user_by_req(request)
         if user_id != requester.user.to_string():
             raise AuthError(403, "Cannot add account data for other users.")
 
         body = parse_json_object_from_request(request)
 
-        max_id = yield self.store.add_account_data_for_user(
+        max_id = await self.store.add_account_data_for_user(
             user_id, account_data_type, body
         )
 
@@ -57,13 +58,12 @@ class AccountDataServlet(RestServlet):
 
         return 200, {}
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, user_id, account_data_type):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_GET(self, request, user_id, account_data_type):
+        requester = await self.auth.get_user_by_req(request)
         if user_id != requester.user.to_string():
             raise AuthError(403, "Cannot get account data for other users.")
 
-        event = yield self.store.get_global_account_data_by_type_for_user(
+        event = await self.store.get_global_account_data_by_type_for_user(
             account_data_type, user_id
         )
 
@@ -90,10 +90,13 @@ class RoomAccountDataServlet(RestServlet):
         self.auth = hs.get_auth()
         self.store = hs.get_datastore()
         self.notifier = hs.get_notifier()
+        self._is_worker = hs.config.worker_app is not None
+
+    async def on_PUT(self, request, user_id, room_id, account_data_type):
+        if self._is_worker:
+            raise Exception("Cannot handle PUT /account_data on worker")
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, user_id, room_id, account_data_type):
-        requester = yield self.auth.get_user_by_req(request)
+        requester = await self.auth.get_user_by_req(request)
         if user_id != requester.user.to_string():
             raise AuthError(403, "Cannot add account data for other users.")
 
@@ -106,7 +109,7 @@ class RoomAccountDataServlet(RestServlet):
                 " Use /rooms/!roomId:server.name/read_markers",
             )
 
-        max_id = yield self.store.add_account_data_to_room(
+        max_id = await self.store.add_account_data_to_room(
             user_id, room_id, account_data_type, body
         )
 
@@ -114,13 +117,12 @@ class RoomAccountDataServlet(RestServlet):
 
         return 200, {}
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, user_id, room_id, account_data_type):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_GET(self, request, user_id, room_id, account_data_type):
+        requester = await self.auth.get_user_by_req(request)
         if user_id != requester.user.to_string():
             raise AuthError(403, "Cannot get account data for other users.")
 
-        event = yield self.store.get_account_data_for_room_and_type(
+        event = await self.store.get_account_data_for_room_and_type(
             user_id, room_id, account_data_type
         )
 
diff --git a/synapse/rest/client/v2_alpha/account_validity.py b/synapse/rest/client/v2_alpha/account_validity.py
index 33f6a23028..2f10fa64e2 100644
--- a/synapse/rest/client/v2_alpha/account_validity.py
+++ b/synapse/rest/client/v2_alpha/account_validity.py
@@ -15,8 +15,6 @@
 
 import logging
 
-from twisted.internet import defer
-
 from synapse.api.errors import AuthError, SynapseError
 from synapse.http.server import finish_request
 from synapse.http.servlet import RestServlet
@@ -45,13 +43,12 @@ class AccountValidityRenewServlet(RestServlet):
         self.success_html = hs.config.account_validity.account_renewed_html_content
         self.failure_html = hs.config.account_validity.invalid_token_html_content
 
-    @defer.inlineCallbacks
-    def on_GET(self, request):
+    async def on_GET(self, request):
         if b"token" not in request.args:
             raise SynapseError(400, "Missing renewal token")
         renewal_token = request.args[b"token"][0]
 
-        token_valid = yield self.account_activity_handler.renew_account(
+        token_valid = await self.account_activity_handler.renew_account(
             renewal_token.decode("utf8")
         )
 
@@ -67,7 +64,6 @@ class AccountValidityRenewServlet(RestServlet):
         request.setHeader(b"Content-Length", b"%d" % (len(response),))
         request.write(response.encode("utf8"))
         finish_request(request)
-        defer.returnValue(None)
 
 
 class AccountValiditySendMailServlet(RestServlet):
@@ -85,18 +81,17 @@ class AccountValiditySendMailServlet(RestServlet):
         self.auth = hs.get_auth()
         self.account_validity = self.hs.config.account_validity
 
-    @defer.inlineCallbacks
-    def on_POST(self, request):
+    async def on_POST(self, request):
         if not self.account_validity.renew_by_email_enabled:
             raise AuthError(
                 403, "Account renewal via email is disabled on this server."
             )
 
-        requester = yield self.auth.get_user_by_req(request, allow_expired=True)
+        requester = await self.auth.get_user_by_req(request, allow_expired=True)
         user_id = requester.user.to_string()
-        yield self.account_activity_handler.send_renewal_email_to_user(user_id)
+        await self.account_activity_handler.send_renewal_email_to_user(user_id)
 
-        defer.returnValue((200, {}))
+        return 200, {}
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/auth.py b/synapse/rest/client/v2_alpha/auth.py
index f21aff39e5..75590ebaeb 100644
--- a/synapse/rest/client/v2_alpha/auth.py
+++ b/synapse/rest/client/v2_alpha/auth.py
@@ -15,8 +15,6 @@
 
 import logging
 
-from twisted.internet import defer
-
 from synapse.api.constants import LoginType
 from synapse.api.errors import SynapseError
 from synapse.api.urls import CLIENT_API_PREFIX
@@ -132,7 +130,22 @@ class AuthRestServlet(RestServlet):
         self.auth_handler = hs.get_auth_handler()
         self.registration_handler = hs.get_registration_handler()
 
-    def on_GET(self, request, stagetype):
+        # SSO configuration.
+        self._cas_enabled = hs.config.cas_enabled
+        if self._cas_enabled:
+            self._cas_handler = hs.get_cas_handler()
+            self._cas_server_url = hs.config.cas_server_url
+            self._cas_service_url = hs.config.cas_service_url
+        self._saml_enabled = hs.config.saml2_enabled
+        if self._saml_enabled:
+            self._saml_handler = hs.get_saml_handler()
+        self._oidc_enabled = hs.config.oidc_enabled
+        if self._oidc_enabled:
+            self._oidc_handler = hs.get_oidc_handler()
+            self._cas_server_url = hs.config.cas_server_url
+            self._cas_service_url = hs.config.cas_service_url
+
+    async def on_GET(self, request, stagetype):
         session = parse_string(request, "session")
         if not session:
             raise SynapseError(400, "No session supplied")
@@ -144,14 +157,6 @@ class AuthRestServlet(RestServlet):
                 % (CLIENT_API_PREFIX, LoginType.RECAPTCHA),
                 "sitekey": self.hs.config.recaptcha_public_key,
             }
-            html_bytes = html.encode("utf8")
-            request.setResponseCode(200)
-            request.setHeader(b"Content-Type", b"text/html; charset=utf-8")
-            request.setHeader(b"Content-Length", b"%d" % (len(html_bytes),))
-
-            request.write(html_bytes)
-            finish_request(request)
-            return None
         elif stagetype == LoginType.TERMS:
             html = TERMS_TEMPLATE % {
                 "session": session,
@@ -160,19 +165,51 @@ class AuthRestServlet(RestServlet):
                 "myurl": "%s/r0/auth/%s/fallback/web"
                 % (CLIENT_API_PREFIX, LoginType.TERMS),
             }
-            html_bytes = html.encode("utf8")
-            request.setResponseCode(200)
-            request.setHeader(b"Content-Type", b"text/html; charset=utf-8")
-            request.setHeader(b"Content-Length", b"%d" % (len(html_bytes),))
-
-            request.write(html_bytes)
-            finish_request(request)
-            return None
+
+        elif stagetype == LoginType.SSO:
+            # Display a confirmation page which prompts the user to
+            # re-authenticate with their SSO provider.
+            if self._cas_enabled:
+                # Generate a request to CAS that redirects back to an endpoint
+                # to verify the successful authentication.
+                sso_redirect_url = self._cas_handler.get_redirect_url(
+                    {"session": session},
+                )
+
+            elif self._saml_enabled:
+                # Some SAML identity providers (e.g. Google) require a
+                # RelayState parameter on requests. It is not necessary here, so
+                # pass in a dummy redirect URL (which will never get used).
+                client_redirect_url = b"unused"
+                sso_redirect_url = self._saml_handler.handle_redirect_request(
+                    client_redirect_url, session
+                )
+
+            elif self._oidc_enabled:
+                client_redirect_url = b""
+                sso_redirect_url = await self._oidc_handler.handle_redirect_request(
+                    request, client_redirect_url, session
+                )
+
+            else:
+                raise SynapseError(400, "Homeserver not configured for SSO.")
+
+            html = await self.auth_handler.start_sso_ui_auth(sso_redirect_url, session)
+
         else:
             raise SynapseError(404, "Unknown auth stage type")
 
-    @defer.inlineCallbacks
-    def on_POST(self, request, stagetype):
+        # Render the HTML and return.
+        html_bytes = html.encode("utf8")
+        request.setResponseCode(200)
+        request.setHeader(b"Content-Type", b"text/html; charset=utf-8")
+        request.setHeader(b"Content-Length", b"%d" % (len(html_bytes),))
+
+        request.write(html_bytes)
+        finish_request(request)
+        return None
+
+    async def on_POST(self, request, stagetype):
 
         session = parse_string(request, "session")
         if not session:
@@ -186,7 +223,7 @@ class AuthRestServlet(RestServlet):
 
             authdict = {"response": response, "session": session}
 
-            success = yield self.auth_handler.add_oob_auth(
+            success = await self.auth_handler.add_oob_auth(
                 LoginType.RECAPTCHA, authdict, self.hs.get_ip_from_request(request)
             )
 
@@ -199,23 +236,10 @@ class AuthRestServlet(RestServlet):
                     % (CLIENT_API_PREFIX, LoginType.RECAPTCHA),
                     "sitekey": self.hs.config.recaptcha_public_key,
                 }
-            html_bytes = html.encode("utf8")
-            request.setResponseCode(200)
-            request.setHeader(b"Content-Type", b"text/html; charset=utf-8")
-            request.setHeader(b"Content-Length", b"%d" % (len(html_bytes),))
-
-            request.write(html_bytes)
-            finish_request(request)
-
-            return None
         elif stagetype == LoginType.TERMS:
-            if ("session" not in request.args or len(request.args["session"])) == 0:
-                raise SynapseError(400, "No session supplied")
-
-            session = request.args["session"][0]
             authdict = {"session": session}
 
-            success = yield self.auth_handler.add_oob_auth(
+            success = await self.auth_handler.add_oob_auth(
                 LoginType.TERMS, authdict, self.hs.get_ip_from_request(request)
             )
 
@@ -232,17 +256,22 @@ class AuthRestServlet(RestServlet):
                     "myurl": "%s/r0/auth/%s/fallback/web"
                     % (CLIENT_API_PREFIX, LoginType.TERMS),
                 }
-            html_bytes = html.encode("utf8")
-            request.setResponseCode(200)
-            request.setHeader(b"Content-Type", b"text/html; charset=utf-8")
-            request.setHeader(b"Content-Length", b"%d" % (len(html_bytes),))
-
-            request.write(html_bytes)
-            finish_request(request)
-            return None
+        elif stagetype == LoginType.SSO:
+            # The SSO fallback workflow should not post here,
+            raise SynapseError(404, "Fallback SSO auth does not support POST requests.")
         else:
             raise SynapseError(404, "Unknown auth stage type")
 
+        # Render the HTML and return.
+        html_bytes = html.encode("utf8")
+        request.setResponseCode(200)
+        request.setHeader(b"Content-Type", b"text/html; charset=utf-8")
+        request.setHeader(b"Content-Length", b"%d" % (len(html_bytes),))
+
+        request.write(html_bytes)
+        finish_request(request)
+        return None
+
     def on_OPTIONS(self, _):
         return 200, {}
 
diff --git a/synapse/rest/client/v2_alpha/capabilities.py b/synapse/rest/client/v2_alpha/capabilities.py
index acd58af193..fe9d019c44 100644
--- a/synapse/rest/client/v2_alpha/capabilities.py
+++ b/synapse/rest/client/v2_alpha/capabilities.py
@@ -14,8 +14,6 @@
 # limitations under the License.
 import logging
 
-from twisted.internet import defer
-
 from synapse.api.room_versions import KNOWN_ROOM_VERSIONS
 from synapse.http.servlet import RestServlet
 
@@ -40,10 +38,9 @@ class CapabilitiesRestServlet(RestServlet):
         self.auth = hs.get_auth()
         self.store = hs.get_datastore()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
-        user = yield self.store.get_user_by_id(requester.user.to_string())
+    async def on_GET(self, request):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
+        user = await self.store.get_user_by_id(requester.user.to_string())
         change_password = bool(user["password_hash"])
 
         response = {
diff --git a/synapse/rest/client/v2_alpha/devices.py b/synapse/rest/client/v2_alpha/devices.py
index 26d0235208..c0714fcfb1 100644
--- a/synapse/rest/client/v2_alpha/devices.py
+++ b/synapse/rest/client/v2_alpha/devices.py
@@ -15,8 +15,6 @@
 
 import logging
 
-from twisted.internet import defer
-
 from synapse.api import errors
 from synapse.http.servlet import (
     RestServlet,
@@ -42,10 +40,9 @@ class DevicesRestServlet(RestServlet):
         self.auth = hs.get_auth()
         self.device_handler = hs.get_device_handler()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
-        devices = yield self.device_handler.get_devices_by_user(
+    async def on_GET(self, request):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
+        devices = await self.device_handler.get_devices_by_user(
             requester.user.to_string()
         )
         return 200, {"devices": devices}
@@ -67,9 +64,8 @@ class DeleteDevicesRestServlet(RestServlet):
         self.auth_handler = hs.get_auth_handler()
 
     @interactive_auth_handler
-    @defer.inlineCallbacks
-    def on_POST(self, request):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_POST(self, request):
+        requester = await self.auth.get_user_by_req(request)
 
         try:
             body = parse_json_object_from_request(request)
@@ -84,11 +80,15 @@ class DeleteDevicesRestServlet(RestServlet):
 
         assert_params_in_dict(body, ["devices"])
 
-        yield self.auth_handler.validate_user_via_ui_auth(
-            requester, body, self.hs.get_ip_from_request(request)
+        await self.auth_handler.validate_user_via_ui_auth(
+            requester,
+            request,
+            body,
+            self.hs.get_ip_from_request(request),
+            "remove device(s) from your account",
         )
 
-        yield self.device_handler.delete_devices(
+        await self.device_handler.delete_devices(
             requester.user.to_string(), body["devices"]
         )
         return 200, {}
@@ -108,18 +108,16 @@ class DeviceRestServlet(RestServlet):
         self.device_handler = hs.get_device_handler()
         self.auth_handler = hs.get_auth_handler()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, device_id):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
-        device = yield self.device_handler.get_device(
+    async def on_GET(self, request, device_id):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
+        device = await self.device_handler.get_device(
             requester.user.to_string(), device_id
         )
         return 200, device
 
     @interactive_auth_handler
-    @defer.inlineCallbacks
-    def on_DELETE(self, request, device_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_DELETE(self, request, device_id):
+        requester = await self.auth.get_user_by_req(request)
 
         try:
             body = parse_json_object_from_request(request)
@@ -132,19 +130,22 @@ class DeviceRestServlet(RestServlet):
             else:
                 raise
 
-        yield self.auth_handler.validate_user_via_ui_auth(
-            requester, body, self.hs.get_ip_from_request(request)
+        await self.auth_handler.validate_user_via_ui_auth(
+            requester,
+            request,
+            body,
+            self.hs.get_ip_from_request(request),
+            "remove a device from your account",
         )
 
-        yield self.device_handler.delete_device(requester.user.to_string(), device_id)
+        await self.device_handler.delete_device(requester.user.to_string(), device_id)
         return 200, {}
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, device_id):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_PUT(self, request, device_id):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
 
         body = parse_json_object_from_request(request)
-        yield self.device_handler.update_device(
+        await self.device_handler.update_device(
             requester.user.to_string(), device_id, body
         )
         return 200, {}
diff --git a/synapse/rest/client/v2_alpha/filter.py b/synapse/rest/client/v2_alpha/filter.py
index c6ddf24c8d..b28da017cd 100644
--- a/synapse/rest/client/v2_alpha/filter.py
+++ b/synapse/rest/client/v2_alpha/filter.py
@@ -15,9 +15,7 @@
 
 import logging
 
-from twisted.internet import defer
-
-from synapse.api.errors import AuthError, Codes, StoreError, SynapseError
+from synapse.api.errors import AuthError, NotFoundError, StoreError, SynapseError
 from synapse.http.servlet import RestServlet, parse_json_object_from_request
 from synapse.types import UserID
 
@@ -35,10 +33,9 @@ class GetFilterRestServlet(RestServlet):
         self.auth = hs.get_auth()
         self.filtering = hs.get_filtering()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, user_id, filter_id):
+    async def on_GET(self, request, user_id, filter_id):
         target_user = UserID.from_string(user_id)
-        requester = yield self.auth.get_user_by_req(request)
+        requester = await self.auth.get_user_by_req(request)
 
         if target_user != requester.user:
             raise AuthError(403, "Cannot get filters for other users")
@@ -52,13 +49,15 @@ class GetFilterRestServlet(RestServlet):
             raise SynapseError(400, "Invalid filter_id")
 
         try:
-            filter = yield self.filtering.get_user_filter(
+            filter_collection = await self.filtering.get_user_filter(
                 user_localpart=target_user.localpart, filter_id=filter_id
             )
+        except StoreError as e:
+            if e.code != 404:
+                raise
+            raise NotFoundError("No such filter")
 
-            return 200, filter.get_filter_json()
-        except (KeyError, StoreError):
-            raise SynapseError(400, "No such filter", errcode=Codes.NOT_FOUND)
+        return 200, filter_collection.get_filter_json()
 
 
 class CreateFilterRestServlet(RestServlet):
@@ -70,11 +69,10 @@ class CreateFilterRestServlet(RestServlet):
         self.auth = hs.get_auth()
         self.filtering = hs.get_filtering()
 
-    @defer.inlineCallbacks
-    def on_POST(self, request, user_id):
+    async def on_POST(self, request, user_id):
 
         target_user = UserID.from_string(user_id)
-        requester = yield self.auth.get_user_by_req(request)
+        requester = await self.auth.get_user_by_req(request)
 
         if target_user != requester.user:
             raise AuthError(403, "Cannot create filters for other users")
@@ -85,7 +83,7 @@ class CreateFilterRestServlet(RestServlet):
         content = parse_json_object_from_request(request)
         set_timeline_upper_limit(content, self.hs.config.filter_timeline_limit)
 
-        filter_id = yield self.filtering.add_user_filter(
+        filter_id = await self.filtering.add_user_filter(
             user_localpart=target_user.localpart, user_filter=content
         )
 
diff --git a/synapse/rest/client/v2_alpha/groups.py b/synapse/rest/client/v2_alpha/groups.py
index 999a0fa80c..d84a6d7e11 100644
--- a/synapse/rest/client/v2_alpha/groups.py
+++ b/synapse/rest/client/v2_alpha/groups.py
@@ -16,8 +16,6 @@
 
 import logging
 
-from twisted.internet import defer
-
 from synapse.http.servlet import RestServlet, parse_json_object_from_request
 from synapse.types import GroupID
 
@@ -38,24 +36,22 @@ class GroupServlet(RestServlet):
         self.clock = hs.get_clock()
         self.groups_handler = hs.get_groups_local_handler()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, group_id):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request, group_id):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
         requester_user_id = requester.user.to_string()
 
-        group_description = yield self.groups_handler.get_group_profile(
+        group_description = await self.groups_handler.get_group_profile(
             group_id, requester_user_id
         )
 
         return 200, group_description
 
-    @defer.inlineCallbacks
-    def on_POST(self, request, group_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_POST(self, request, group_id):
+        requester = await self.auth.get_user_by_req(request)
         requester_user_id = requester.user.to_string()
 
         content = parse_json_object_from_request(request)
-        yield self.groups_handler.update_group_profile(
+        await self.groups_handler.update_group_profile(
             group_id, requester_user_id, content
         )
 
@@ -74,12 +70,11 @@ class GroupSummaryServlet(RestServlet):
         self.clock = hs.get_clock()
         self.groups_handler = hs.get_groups_local_handler()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, group_id):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request, group_id):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
         requester_user_id = requester.user.to_string()
 
-        get_group_summary = yield self.groups_handler.get_group_summary(
+        get_group_summary = await self.groups_handler.get_group_summary(
             group_id, requester_user_id
         )
 
@@ -106,13 +101,12 @@ class GroupSummaryRoomsCatServlet(RestServlet):
         self.clock = hs.get_clock()
         self.groups_handler = hs.get_groups_local_handler()
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, group_id, category_id, room_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_PUT(self, request, group_id, category_id, room_id):
+        requester = await self.auth.get_user_by_req(request)
         requester_user_id = requester.user.to_string()
 
         content = parse_json_object_from_request(request)
-        resp = yield self.groups_handler.update_group_summary_room(
+        resp = await self.groups_handler.update_group_summary_room(
             group_id,
             requester_user_id,
             room_id=room_id,
@@ -122,12 +116,11 @@ class GroupSummaryRoomsCatServlet(RestServlet):
 
         return 200, resp
 
-    @defer.inlineCallbacks
-    def on_DELETE(self, request, group_id, category_id, room_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_DELETE(self, request, group_id, category_id, room_id):
+        requester = await self.auth.get_user_by_req(request)
         requester_user_id = requester.user.to_string()
 
-        resp = yield self.groups_handler.delete_group_summary_room(
+        resp = await self.groups_handler.delete_group_summary_room(
             group_id, requester_user_id, room_id=room_id, category_id=category_id
         )
 
@@ -148,35 +141,32 @@ class GroupCategoryServlet(RestServlet):
         self.clock = hs.get_clock()
         self.groups_handler = hs.get_groups_local_handler()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, group_id, category_id):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request, group_id, category_id):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
         requester_user_id = requester.user.to_string()
 
-        category = yield self.groups_handler.get_group_category(
+        category = await self.groups_handler.get_group_category(
             group_id, requester_user_id, category_id=category_id
         )
 
         return 200, category
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, group_id, category_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_PUT(self, request, group_id, category_id):
+        requester = await self.auth.get_user_by_req(request)
         requester_user_id = requester.user.to_string()
 
         content = parse_json_object_from_request(request)
-        resp = yield self.groups_handler.update_group_category(
+        resp = await self.groups_handler.update_group_category(
             group_id, requester_user_id, category_id=category_id, content=content
         )
 
         return 200, resp
 
-    @defer.inlineCallbacks
-    def on_DELETE(self, request, group_id, category_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_DELETE(self, request, group_id, category_id):
+        requester = await self.auth.get_user_by_req(request)
         requester_user_id = requester.user.to_string()
 
-        resp = yield self.groups_handler.delete_group_category(
+        resp = await self.groups_handler.delete_group_category(
             group_id, requester_user_id, category_id=category_id
         )
 
@@ -195,12 +185,11 @@ class GroupCategoriesServlet(RestServlet):
         self.clock = hs.get_clock()
         self.groups_handler = hs.get_groups_local_handler()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, group_id):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request, group_id):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
         requester_user_id = requester.user.to_string()
 
-        category = yield self.groups_handler.get_group_categories(
+        category = await self.groups_handler.get_group_categories(
             group_id, requester_user_id
         )
 
@@ -219,35 +208,32 @@ class GroupRoleServlet(RestServlet):
         self.clock = hs.get_clock()
         self.groups_handler = hs.get_groups_local_handler()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, group_id, role_id):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request, group_id, role_id):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
         requester_user_id = requester.user.to_string()
 
-        category = yield self.groups_handler.get_group_role(
+        category = await self.groups_handler.get_group_role(
             group_id, requester_user_id, role_id=role_id
         )
 
         return 200, category
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, group_id, role_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_PUT(self, request, group_id, role_id):
+        requester = await self.auth.get_user_by_req(request)
         requester_user_id = requester.user.to_string()
 
         content = parse_json_object_from_request(request)
-        resp = yield self.groups_handler.update_group_role(
+        resp = await self.groups_handler.update_group_role(
             group_id, requester_user_id, role_id=role_id, content=content
         )
 
         return 200, resp
 
-    @defer.inlineCallbacks
-    def on_DELETE(self, request, group_id, role_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_DELETE(self, request, group_id, role_id):
+        requester = await self.auth.get_user_by_req(request)
         requester_user_id = requester.user.to_string()
 
-        resp = yield self.groups_handler.delete_group_role(
+        resp = await self.groups_handler.delete_group_role(
             group_id, requester_user_id, role_id=role_id
         )
 
@@ -266,12 +252,11 @@ class GroupRolesServlet(RestServlet):
         self.clock = hs.get_clock()
         self.groups_handler = hs.get_groups_local_handler()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, group_id):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request, group_id):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
         requester_user_id = requester.user.to_string()
 
-        category = yield self.groups_handler.get_group_roles(
+        category = await self.groups_handler.get_group_roles(
             group_id, requester_user_id
         )
 
@@ -298,13 +283,12 @@ class GroupSummaryUsersRoleServlet(RestServlet):
         self.clock = hs.get_clock()
         self.groups_handler = hs.get_groups_local_handler()
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, group_id, role_id, user_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_PUT(self, request, group_id, role_id, user_id):
+        requester = await self.auth.get_user_by_req(request)
         requester_user_id = requester.user.to_string()
 
         content = parse_json_object_from_request(request)
-        resp = yield self.groups_handler.update_group_summary_user(
+        resp = await self.groups_handler.update_group_summary_user(
             group_id,
             requester_user_id,
             user_id=user_id,
@@ -314,12 +298,11 @@ class GroupSummaryUsersRoleServlet(RestServlet):
 
         return 200, resp
 
-    @defer.inlineCallbacks
-    def on_DELETE(self, request, group_id, role_id, user_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_DELETE(self, request, group_id, role_id, user_id):
+        requester = await self.auth.get_user_by_req(request)
         requester_user_id = requester.user.to_string()
 
-        resp = yield self.groups_handler.delete_group_summary_user(
+        resp = await self.groups_handler.delete_group_summary_user(
             group_id, requester_user_id, user_id=user_id, role_id=role_id
         )
 
@@ -338,12 +321,11 @@ class GroupRoomServlet(RestServlet):
         self.clock = hs.get_clock()
         self.groups_handler = hs.get_groups_local_handler()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, group_id):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request, group_id):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
         requester_user_id = requester.user.to_string()
 
-        result = yield self.groups_handler.get_rooms_in_group(
+        result = await self.groups_handler.get_rooms_in_group(
             group_id, requester_user_id
         )
 
@@ -362,12 +344,11 @@ class GroupUsersServlet(RestServlet):
         self.clock = hs.get_clock()
         self.groups_handler = hs.get_groups_local_handler()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, group_id):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request, group_id):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
         requester_user_id = requester.user.to_string()
 
-        result = yield self.groups_handler.get_users_in_group(
+        result = await self.groups_handler.get_users_in_group(
             group_id, requester_user_id
         )
 
@@ -386,12 +367,11 @@ class GroupInvitedUsersServlet(RestServlet):
         self.clock = hs.get_clock()
         self.groups_handler = hs.get_groups_local_handler()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, group_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_GET(self, request, group_id):
+        requester = await self.auth.get_user_by_req(request)
         requester_user_id = requester.user.to_string()
 
-        result = yield self.groups_handler.get_invited_users_in_group(
+        result = await self.groups_handler.get_invited_users_in_group(
             group_id, requester_user_id
         )
 
@@ -409,14 +389,13 @@ class GroupSettingJoinPolicyServlet(RestServlet):
         self.auth = hs.get_auth()
         self.groups_handler = hs.get_groups_local_handler()
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, group_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_PUT(self, request, group_id):
+        requester = await self.auth.get_user_by_req(request)
         requester_user_id = requester.user.to_string()
 
         content = parse_json_object_from_request(request)
 
-        result = yield self.groups_handler.set_group_join_policy(
+        result = await self.groups_handler.set_group_join_policy(
             group_id, requester_user_id, content
         )
 
@@ -436,9 +415,8 @@ class GroupCreateServlet(RestServlet):
         self.groups_handler = hs.get_groups_local_handler()
         self.server_name = hs.hostname
 
-    @defer.inlineCallbacks
-    def on_POST(self, request):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_POST(self, request):
+        requester = await self.auth.get_user_by_req(request)
         requester_user_id = requester.user.to_string()
 
         # TODO: Create group on remote server
@@ -446,7 +424,7 @@ class GroupCreateServlet(RestServlet):
         localpart = content.pop("localpart")
         group_id = GroupID(localpart, self.server_name).to_string()
 
-        result = yield self.groups_handler.create_group(
+        result = await self.groups_handler.create_group(
             group_id, requester_user_id, content
         )
 
@@ -467,24 +445,22 @@ class GroupAdminRoomsServlet(RestServlet):
         self.clock = hs.get_clock()
         self.groups_handler = hs.get_groups_local_handler()
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, group_id, room_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_PUT(self, request, group_id, room_id):
+        requester = await self.auth.get_user_by_req(request)
         requester_user_id = requester.user.to_string()
 
         content = parse_json_object_from_request(request)
-        result = yield self.groups_handler.add_room_to_group(
+        result = await self.groups_handler.add_room_to_group(
             group_id, requester_user_id, room_id, content
         )
 
         return 200, result
 
-    @defer.inlineCallbacks
-    def on_DELETE(self, request, group_id, room_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_DELETE(self, request, group_id, room_id):
+        requester = await self.auth.get_user_by_req(request)
         requester_user_id = requester.user.to_string()
 
-        result = yield self.groups_handler.remove_room_from_group(
+        result = await self.groups_handler.remove_room_from_group(
             group_id, requester_user_id, room_id
         )
 
@@ -506,13 +482,12 @@ class GroupAdminRoomsConfigServlet(RestServlet):
         self.clock = hs.get_clock()
         self.groups_handler = hs.get_groups_local_handler()
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, group_id, room_id, config_key):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_PUT(self, request, group_id, room_id, config_key):
+        requester = await self.auth.get_user_by_req(request)
         requester_user_id = requester.user.to_string()
 
         content = parse_json_object_from_request(request)
-        result = yield self.groups_handler.update_room_in_group(
+        result = await self.groups_handler.update_room_in_group(
             group_id, requester_user_id, room_id, config_key, content
         )
 
@@ -535,14 +510,13 @@ class GroupAdminUsersInviteServlet(RestServlet):
         self.store = hs.get_datastore()
         self.is_mine_id = hs.is_mine_id
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, group_id, user_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_PUT(self, request, group_id, user_id):
+        requester = await self.auth.get_user_by_req(request)
         requester_user_id = requester.user.to_string()
 
         content = parse_json_object_from_request(request)
         config = content.get("config", {})
-        result = yield self.groups_handler.invite(
+        result = await self.groups_handler.invite(
             group_id, user_id, requester_user_id, config
         )
 
@@ -563,13 +537,12 @@ class GroupAdminUsersKickServlet(RestServlet):
         self.clock = hs.get_clock()
         self.groups_handler = hs.get_groups_local_handler()
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, group_id, user_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_PUT(self, request, group_id, user_id):
+        requester = await self.auth.get_user_by_req(request)
         requester_user_id = requester.user.to_string()
 
         content = parse_json_object_from_request(request)
-        result = yield self.groups_handler.remove_user_from_group(
+        result = await self.groups_handler.remove_user_from_group(
             group_id, user_id, requester_user_id, content
         )
 
@@ -588,13 +561,12 @@ class GroupSelfLeaveServlet(RestServlet):
         self.clock = hs.get_clock()
         self.groups_handler = hs.get_groups_local_handler()
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, group_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_PUT(self, request, group_id):
+        requester = await self.auth.get_user_by_req(request)
         requester_user_id = requester.user.to_string()
 
         content = parse_json_object_from_request(request)
-        result = yield self.groups_handler.remove_user_from_group(
+        result = await self.groups_handler.remove_user_from_group(
             group_id, requester_user_id, requester_user_id, content
         )
 
@@ -613,13 +585,12 @@ class GroupSelfJoinServlet(RestServlet):
         self.clock = hs.get_clock()
         self.groups_handler = hs.get_groups_local_handler()
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, group_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_PUT(self, request, group_id):
+        requester = await self.auth.get_user_by_req(request)
         requester_user_id = requester.user.to_string()
 
         content = parse_json_object_from_request(request)
-        result = yield self.groups_handler.join_group(
+        result = await self.groups_handler.join_group(
             group_id, requester_user_id, content
         )
 
@@ -638,13 +609,12 @@ class GroupSelfAcceptInviteServlet(RestServlet):
         self.clock = hs.get_clock()
         self.groups_handler = hs.get_groups_local_handler()
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, group_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_PUT(self, request, group_id):
+        requester = await self.auth.get_user_by_req(request)
         requester_user_id = requester.user.to_string()
 
         content = parse_json_object_from_request(request)
-        result = yield self.groups_handler.accept_invite(
+        result = await self.groups_handler.accept_invite(
             group_id, requester_user_id, content
         )
 
@@ -663,14 +633,13 @@ class GroupSelfUpdatePublicityServlet(RestServlet):
         self.clock = hs.get_clock()
         self.store = hs.get_datastore()
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, group_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_PUT(self, request, group_id):
+        requester = await self.auth.get_user_by_req(request)
         requester_user_id = requester.user.to_string()
 
         content = parse_json_object_from_request(request)
         publicise = content["publicise"]
-        yield self.store.update_group_publicity(group_id, requester_user_id, publicise)
+        await self.store.update_group_publicity(group_id, requester_user_id, publicise)
 
         return 200, {}
 
@@ -688,11 +657,10 @@ class PublicisedGroupsForUserServlet(RestServlet):
         self.store = hs.get_datastore()
         self.groups_handler = hs.get_groups_local_handler()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, user_id):
-        yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request, user_id):
+        await self.auth.get_user_by_req(request, allow_guest=True)
 
-        result = yield self.groups_handler.get_publicised_groups_for_user(user_id)
+        result = await self.groups_handler.get_publicised_groups_for_user(user_id)
 
         return 200, result
 
@@ -710,14 +678,13 @@ class PublicisedGroupsForUsersServlet(RestServlet):
         self.store = hs.get_datastore()
         self.groups_handler = hs.get_groups_local_handler()
 
-    @defer.inlineCallbacks
-    def on_POST(self, request):
-        yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_POST(self, request):
+        await self.auth.get_user_by_req(request, allow_guest=True)
 
         content = parse_json_object_from_request(request)
         user_ids = content["user_ids"]
 
-        result = yield self.groups_handler.bulk_get_publicised_groups(user_ids)
+        result = await self.groups_handler.bulk_get_publicised_groups(user_ids)
 
         return 200, result
 
@@ -734,12 +701,11 @@ class GroupsForUserServlet(RestServlet):
         self.clock = hs.get_clock()
         self.groups_handler = hs.get_groups_local_handler()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
         requester_user_id = requester.user.to_string()
 
-        result = yield self.groups_handler.get_joined_groups(requester_user_id)
+        result = await self.groups_handler.get_joined_groups(requester_user_id)
 
         return 200, result
 
diff --git a/synapse/rest/client/v2_alpha/keys.py b/synapse/rest/client/v2_alpha/keys.py
index 2e680134a0..24bb090822 100644
--- a/synapse/rest/client/v2_alpha/keys.py
+++ b/synapse/rest/client/v2_alpha/keys.py
@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
 # Copyright 2015, 2016 OpenMarket Ltd
+# Copyright 2019 New Vector Ltd
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -15,8 +16,6 @@
 
 import logging
 
-from twisted.internet import defer
-
 from synapse.api.errors import SynapseError
 from synapse.http.servlet import (
     RestServlet,
@@ -27,7 +26,7 @@ from synapse.http.servlet import (
 from synapse.logging.opentracing import log_kv, set_tag, trace
 from synapse.types import StreamToken
 
-from ._base import client_patterns
+from ._base import client_patterns, interactive_auth_handler
 
 logger = logging.getLogger(__name__)
 
@@ -43,7 +42,7 @@ class KeyUploadServlet(RestServlet):
         "device_id": "<device_id>",
         "valid_until_ts": <millisecond_timestamp>,
         "algorithms": [
-          "m.olm.curve25519-aes-sha256",
+          "m.olm.curve25519-aes-sha2",
         ]
         "keys": {
           "<algorithm>:<device_id>": "<key_base64>",
@@ -70,9 +69,8 @@ class KeyUploadServlet(RestServlet):
         self.e2e_keys_handler = hs.get_e2e_keys_handler()
 
     @trace(opname="upload_keys")
-    @defer.inlineCallbacks
-    def on_POST(self, request, device_id):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_POST(self, request, device_id):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
         user_id = requester.user.to_string()
         body = parse_json_object_from_request(request)
 
@@ -102,7 +100,7 @@ class KeyUploadServlet(RestServlet):
                 400, "To upload keys, you must pass device_id when authenticating"
             )
 
-        result = yield self.e2e_keys_handler.upload_keys_for_user(
+        result = await self.e2e_keys_handler.upload_keys_for_user(
             user_id, device_id, body
         )
         return 200, result
@@ -126,7 +124,7 @@ class KeyQueryServlet(RestServlet):
             "device_id": "<device_id>", // Duplicated to be signed
             "valid_until_ts": <millisecond_timestamp>,
             "algorithms": [ // List of supported algorithms
-              "m.olm.curve25519-aes-sha256",
+              "m.olm.curve25519-aes-sha2",
             ],
             "keys": { // Must include a ed25519 signing key
               "<algorithm>:<key_id>": "<key_base64>",
@@ -153,12 +151,12 @@ class KeyQueryServlet(RestServlet):
         self.auth = hs.get_auth()
         self.e2e_keys_handler = hs.get_e2e_keys_handler()
 
-    @defer.inlineCallbacks
-    def on_POST(self, request):
-        yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_POST(self, request):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
+        user_id = requester.user.to_string()
         timeout = parse_integer(request, "timeout", 10 * 1000)
         body = parse_json_object_from_request(request)
-        result = yield self.e2e_keys_handler.query_devices(body, timeout)
+        result = await self.e2e_keys_handler.query_devices(body, timeout, user_id)
         return 200, result
 
 
@@ -183,9 +181,8 @@ class KeyChangesServlet(RestServlet):
         self.auth = hs.get_auth()
         self.device_handler = hs.get_device_handler()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
 
         from_token_string = parse_string(request, "from")
         set_tag("from", from_token_string)
@@ -198,7 +195,7 @@ class KeyChangesServlet(RestServlet):
 
         user_id = requester.user.to_string()
 
-        results = yield self.device_handler.get_user_ids_changed(user_id, from_token)
+        results = await self.device_handler.get_user_ids_changed(user_id, from_token)
 
         return 200, results
 
@@ -229,12 +226,100 @@ class OneTimeKeyServlet(RestServlet):
         self.auth = hs.get_auth()
         self.e2e_keys_handler = hs.get_e2e_keys_handler()
 
-    @defer.inlineCallbacks
-    def on_POST(self, request):
-        yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_POST(self, request):
+        await self.auth.get_user_by_req(request, allow_guest=True)
         timeout = parse_integer(request, "timeout", 10 * 1000)
         body = parse_json_object_from_request(request)
-        result = yield self.e2e_keys_handler.claim_one_time_keys(body, timeout)
+        result = await self.e2e_keys_handler.claim_one_time_keys(body, timeout)
+        return 200, result
+
+
+class SigningKeyUploadServlet(RestServlet):
+    """
+    POST /keys/device_signing/upload HTTP/1.1
+    Content-Type: application/json
+
+    {
+    }
+    """
+
+    PATTERNS = client_patterns("/keys/device_signing/upload$", releases=())
+
+    def __init__(self, hs):
+        """
+        Args:
+            hs (synapse.server.HomeServer): server
+        """
+        super(SigningKeyUploadServlet, self).__init__()
+        self.hs = hs
+        self.auth = hs.get_auth()
+        self.e2e_keys_handler = hs.get_e2e_keys_handler()
+        self.auth_handler = hs.get_auth_handler()
+
+    @interactive_auth_handler
+    async def on_POST(self, request):
+        requester = await self.auth.get_user_by_req(request)
+        user_id = requester.user.to_string()
+        body = parse_json_object_from_request(request)
+
+        await self.auth_handler.validate_user_via_ui_auth(
+            requester,
+            request,
+            body,
+            self.hs.get_ip_from_request(request),
+            "add a device signing key to your account",
+        )
+
+        result = await self.e2e_keys_handler.upload_signing_keys_for_user(user_id, body)
+        return 200, result
+
+
+class SignaturesUploadServlet(RestServlet):
+    """
+    POST /keys/signatures/upload HTTP/1.1
+    Content-Type: application/json
+
+    {
+      "@alice:example.com": {
+        "<device_id>": {
+          "user_id": "<user_id>",
+          "device_id": "<device_id>",
+          "algorithms": [
+            "m.olm.curve25519-aes-sha2",
+            "m.megolm.v1.aes-sha2"
+          ],
+          "keys": {
+            "<algorithm>:<device_id>": "<key_base64>",
+          },
+          "signatures": {
+            "<signing_user_id>": {
+              "<algorithm>:<signing_key_base64>": "<signature_base64>>"
+            }
+          }
+        }
+      }
+    }
+    """
+
+    PATTERNS = client_patterns("/keys/signatures/upload$")
+
+    def __init__(self, hs):
+        """
+        Args:
+            hs (synapse.server.HomeServer): server
+        """
+        super(SignaturesUploadServlet, self).__init__()
+        self.auth = hs.get_auth()
+        self.e2e_keys_handler = hs.get_e2e_keys_handler()
+
+    async def on_POST(self, request):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
+        user_id = requester.user.to_string()
+        body = parse_json_object_from_request(request)
+
+        result = await self.e2e_keys_handler.upload_signatures_for_device_keys(
+            user_id, body
+        )
         return 200, result
 
 
@@ -243,3 +328,5 @@ def register_servlets(hs, http_server):
     KeyQueryServlet(hs).register(http_server)
     KeyChangesServlet(hs).register(http_server)
     OneTimeKeyServlet(hs).register(http_server)
+    SigningKeyUploadServlet(hs).register(http_server)
+    SignaturesUploadServlet(hs).register(http_server)
diff --git a/synapse/rest/client/v2_alpha/notifications.py b/synapse/rest/client/v2_alpha/notifications.py
index 10c1ad5b07..aa911d75ee 100644
--- a/synapse/rest/client/v2_alpha/notifications.py
+++ b/synapse/rest/client/v2_alpha/notifications.py
@@ -15,8 +15,6 @@
 
 import logging
 
-from twisted.internet import defer
-
 from synapse.events.utils import format_event_for_client_v2_without_room_id
 from synapse.http.servlet import RestServlet, parse_integer, parse_string
 
@@ -35,9 +33,8 @@ class NotificationsServlet(RestServlet):
         self.clock = hs.get_clock()
         self._event_serializer = hs.get_event_client_serializer()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_GET(self, request):
+        requester = await self.auth.get_user_by_req(request)
         user_id = requester.user.to_string()
 
         from_token = parse_string(request, "from", required=False)
@@ -46,16 +43,16 @@ class NotificationsServlet(RestServlet):
 
         limit = min(limit, 500)
 
-        push_actions = yield self.store.get_push_actions_for_user(
+        push_actions = await self.store.get_push_actions_for_user(
             user_id, from_token, limit, only_highlight=(only == "highlight")
         )
 
-        receipts_by_room = yield self.store.get_receipts_for_user_with_orderings(
+        receipts_by_room = await self.store.get_receipts_for_user_with_orderings(
             user_id, "m.read"
         )
 
         notif_event_ids = [pa["event_id"] for pa in push_actions]
-        notif_events = yield self.store.get_events(notif_event_ids)
+        notif_events = await self.store.get_events(notif_event_ids)
 
         returned_push_actions = []
 
@@ -68,7 +65,7 @@ class NotificationsServlet(RestServlet):
                 "actions": pa["actions"],
                 "ts": pa["received_ts"],
                 "event": (
-                    yield self._event_serializer.serialize_event(
+                    await self._event_serializer.serialize_event(
                         notif_events[pa["event_id"]],
                         self.clock.time_msec(),
                         event_format=format_event_for_client_v2_without_room_id,
diff --git a/synapse/rest/client/v2_alpha/openid.py b/synapse/rest/client/v2_alpha/openid.py
index b4925c0f59..6ae9a5a8e9 100644
--- a/synapse/rest/client/v2_alpha/openid.py
+++ b/synapse/rest/client/v2_alpha/openid.py
@@ -16,8 +16,6 @@
 
 import logging
 
-from twisted.internet import defer
-
 from synapse.api.errors import AuthError
 from synapse.http.servlet import RestServlet, parse_json_object_from_request
 from synapse.util.stringutils import random_string
@@ -68,9 +66,8 @@ class IdTokenServlet(RestServlet):
         self.clock = hs.get_clock()
         self.server_name = hs.config.server_name
 
-    @defer.inlineCallbacks
-    def on_POST(self, request, user_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_POST(self, request, user_id):
+        requester = await self.auth.get_user_by_req(request)
         if user_id != requester.user.to_string():
             raise AuthError(403, "Cannot request tokens for other users.")
 
@@ -81,7 +78,7 @@ class IdTokenServlet(RestServlet):
         token = random_string(24)
         ts_valid_until_ms = self.clock.time_msec() + self.EXPIRES_MS
 
-        yield self.store.insert_open_id_token(token, ts_valid_until_ms, user_id)
+        await self.store.insert_open_id_token(token, ts_valid_until_ms, user_id)
 
         return (
             200,
diff --git a/synapse/rest/client/v2_alpha/password_policy.py b/synapse/rest/client/v2_alpha/password_policy.py
new file mode 100644
index 0000000000..968403cca4
--- /dev/null
+++ b/synapse/rest/client/v2_alpha/password_policy.py
@@ -0,0 +1,58 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import logging
+
+from synapse.http.servlet import RestServlet
+
+from ._base import client_patterns
+
+logger = logging.getLogger(__name__)
+
+
+class PasswordPolicyServlet(RestServlet):
+    PATTERNS = client_patterns("/password_policy$")
+
+    def __init__(self, hs):
+        """
+        Args:
+            hs (synapse.server.HomeServer): server
+        """
+        super(PasswordPolicyServlet, self).__init__()
+
+        self.policy = hs.config.password_policy
+        self.enabled = hs.config.password_policy_enabled
+
+    def on_GET(self, request):
+        if not self.enabled or not self.policy:
+            return (200, {})
+
+        policy = {}
+
+        for param in [
+            "minimum_length",
+            "require_digit",
+            "require_symbol",
+            "require_lowercase",
+            "require_uppercase",
+        ]:
+            if param in self.policy:
+                policy["m.%s" % param] = self.policy[param]
+
+        return (200, policy)
+
+
+def register_servlets(hs, http_server):
+    PasswordPolicyServlet(hs).register(http_server)
diff --git a/synapse/rest/client/v2_alpha/read_marker.py b/synapse/rest/client/v2_alpha/read_marker.py
index b3bf8567e1..67cbc37312 100644
--- a/synapse/rest/client/v2_alpha/read_marker.py
+++ b/synapse/rest/client/v2_alpha/read_marker.py
@@ -15,8 +15,6 @@
 
 import logging
 
-from twisted.internet import defer
-
 from synapse.http.servlet import RestServlet, parse_json_object_from_request
 
 from ._base import client_patterns
@@ -34,17 +32,16 @@ class ReadMarkerRestServlet(RestServlet):
         self.read_marker_handler = hs.get_read_marker_handler()
         self.presence_handler = hs.get_presence_handler()
 
-    @defer.inlineCallbacks
-    def on_POST(self, request, room_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_POST(self, request, room_id):
+        requester = await self.auth.get_user_by_req(request)
 
-        yield self.presence_handler.bump_presence_active_time(requester.user)
+        await self.presence_handler.bump_presence_active_time(requester.user)
 
         body = parse_json_object_from_request(request)
 
         read_event_id = body.get("m.read", None)
         if read_event_id:
-            yield self.receipts_handler.received_client_receipt(
+            await self.receipts_handler.received_client_receipt(
                 room_id,
                 "m.read",
                 user_id=requester.user.to_string(),
@@ -53,7 +50,7 @@ class ReadMarkerRestServlet(RestServlet):
 
         read_marker_event_id = body.get("m.fully_read", None)
         if read_marker_event_id:
-            yield self.read_marker_handler.received_client_read_marker(
+            await self.read_marker_handler.received_client_read_marker(
                 room_id,
                 user_id=requester.user.to_string(),
                 event_id=read_marker_event_id,
diff --git a/synapse/rest/client/v2_alpha/receipts.py b/synapse/rest/client/v2_alpha/receipts.py
index 0dab03d227..92555bd4a9 100644
--- a/synapse/rest/client/v2_alpha/receipts.py
+++ b/synapse/rest/client/v2_alpha/receipts.py
@@ -15,8 +15,6 @@
 
 import logging
 
-from twisted.internet import defer
-
 from synapse.api.errors import SynapseError
 from synapse.http.servlet import RestServlet
 
@@ -39,16 +37,15 @@ class ReceiptRestServlet(RestServlet):
         self.receipts_handler = hs.get_receipts_handler()
         self.presence_handler = hs.get_presence_handler()
 
-    @defer.inlineCallbacks
-    def on_POST(self, request, room_id, receipt_type, event_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_POST(self, request, room_id, receipt_type, event_id):
+        requester = await self.auth.get_user_by_req(request)
 
         if receipt_type != "m.read":
             raise SynapseError(400, "Receipt type must be 'm.read'")
 
-        yield self.presence_handler.bump_presence_active_time(requester.user)
+        await self.presence_handler.bump_presence_active_time(requester.user)
 
-        yield self.receipts_handler.received_client_receipt(
+        await self.receipts_handler.received_client_receipt(
             room_id, receipt_type, user_id=requester.user.to_string(), event_id=event_id
         )
 
diff --git a/synapse/rest/client/v2_alpha/register.py b/synapse/rest/client/v2_alpha/register.py
index 5c7a5f3579..b9ffe86b2a 100644
--- a/synapse/rest/client/v2_alpha/register.py
+++ b/synapse/rest/client/v2_alpha/register.py
@@ -16,24 +16,28 @@
 
 import hmac
 import logging
+from typing import List, Union
 
 from six import string_types
 
-from twisted.internet import defer
-
 import synapse
+import synapse.api.auth
 import synapse.types
 from synapse.api.constants import LoginType
 from synapse.api.errors import (
     Codes,
-    LimitExceededError,
     SynapseError,
     ThreepidValidationError,
     UnrecognizedRequestError,
 )
+from synapse.config import ConfigError
+from synapse.config.captcha import CaptchaConfig
+from synapse.config.consent_config import ConsentConfig
 from synapse.config.emailconfig import ThreepidBehaviour
 from synapse.config.ratelimiting import FederationRateLimitConfig
+from synapse.config.registration import RegistrationConfig
 from synapse.config.server import is_threepid_reserved
+from synapse.handlers.auth import AuthHandler
 from synapse.http.server import finish_request
 from synapse.http.servlet import (
     RestServlet,
@@ -44,6 +48,7 @@ from synapse.http.servlet import (
 from synapse.push.mailer import load_jinja2_templates
 from synapse.util.msisdn import phone_number_to_msisdn
 from synapse.util.ratelimitutils import FederationRateLimiter
+from synapse.util.stringutils import assert_valid_client_secret, random_string
 from synapse.util.threepids import check_3pid_allowed
 
 from ._base import client_patterns, interactive_auth_handler
@@ -96,11 +101,10 @@ class EmailRegisterRequestTokenRestServlet(RestServlet):
                 template_text=template_text,
             )
 
-    @defer.inlineCallbacks
-    def on_POST(self, request):
+    async def on_POST(self, request):
         if self.hs.config.threepid_behaviour_email == ThreepidBehaviour.OFF:
             if self.hs.config.local_threepid_handling_disabled_due_to_email_config:
-                logger.warn(
+                logger.warning(
                     "Email registration has been disabled due to lack of email config"
                 )
             raise SynapseError(
@@ -112,6 +116,8 @@ class EmailRegisterRequestTokenRestServlet(RestServlet):
 
         # Extract params from body
         client_secret = body["client_secret"]
+        assert_valid_client_secret(client_secret)
+
         email = body["email"]
         send_attempt = body["send_attempt"]
         next_link = body.get("next_link")  # Optional param
@@ -123,24 +129,23 @@ class EmailRegisterRequestTokenRestServlet(RestServlet):
                 Codes.THREEPID_DENIED,
             )
 
-        existing_user_id = yield self.hs.get_datastore().get_user_id_by_threepid(
+        existing_user_id = await self.hs.get_datastore().get_user_id_by_threepid(
             "email", body["email"]
         )
 
         if existing_user_id is not None:
+            if self.hs.config.request_token_inhibit_3pid_errors:
+                # Make the client think the operation succeeded. See the rationale in the
+                # comments for request_token_inhibit_3pid_errors.
+                return 200, {"sid": random_string(16)}
+
             raise SynapseError(400, "Email is already in use", Codes.THREEPID_IN_USE)
 
         if self.config.threepid_behaviour_email == ThreepidBehaviour.REMOTE:
-            if not self.hs.config.account_threepid_delegate_email:
-                logger.warn(
-                    "No upstream email account_threepid_delegate configured on the server to "
-                    "handle this request"
-                )
-                raise SynapseError(
-                    400, "Registration by email is not supported on this homeserver"
-                )
+            assert self.hs.config.account_threepid_delegate_email
 
-            ret = yield self.identity_handler.requestEmailToken(
+            # Have the configured identity server handle the request
+            ret = await self.identity_handler.requestEmailToken(
                 self.hs.config.account_threepid_delegate_email,
                 email,
                 client_secret,
@@ -149,7 +154,7 @@ class EmailRegisterRequestTokenRestServlet(RestServlet):
             )
         else:
             # Send registration emails from Synapse
-            sid = yield self.identity_handler.send_threepid_validation(
+            sid = await self.identity_handler.send_threepid_validation(
                 email,
                 client_secret,
                 send_attempt,
@@ -175,8 +180,7 @@ class MsisdnRegisterRequestTokenRestServlet(RestServlet):
         self.hs = hs
         self.identity_handler = hs.get_handlers().identity_handler
 
-    @defer.inlineCallbacks
-    def on_POST(self, request):
+    async def on_POST(self, request):
         body = parse_json_object_from_request(request)
 
         assert_params_in_dict(
@@ -197,17 +201,22 @@ class MsisdnRegisterRequestTokenRestServlet(RestServlet):
                 Codes.THREEPID_DENIED,
             )
 
-        existing_user_id = yield self.hs.get_datastore().get_user_id_by_threepid(
+        existing_user_id = await self.hs.get_datastore().get_user_id_by_threepid(
             "msisdn", msisdn
         )
 
         if existing_user_id is not None:
+            if self.hs.config.request_token_inhibit_3pid_errors:
+                # Make the client think the operation succeeded. See the rationale in the
+                # comments for request_token_inhibit_3pid_errors.
+                return 200, {"sid": random_string(16)}
+
             raise SynapseError(
                 400, "Phone number is already in use", Codes.THREEPID_IN_USE
             )
 
         if not self.hs.config.account_threepid_delegate_msisdn:
-            logger.warn(
+            logger.warning(
                 "No upstream msisdn account_threepid_delegate configured on the server to "
                 "handle this request"
             )
@@ -215,7 +224,7 @@ class MsisdnRegisterRequestTokenRestServlet(RestServlet):
                 400, "Registration by phone number is not supported on this homeserver"
             )
 
-        ret = yield self.identity_handler.requestMsisdnToken(
+        ret = await self.identity_handler.requestMsisdnToken(
             self.hs.config.account_threepid_delegate_msisdn,
             country,
             phone_number,
@@ -246,15 +255,26 @@ class RegistrationSubmitTokenServlet(RestServlet):
         self.clock = hs.get_clock()
         self.store = hs.get_datastore()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, medium):
+        if self.config.threepid_behaviour_email == ThreepidBehaviour.LOCAL:
+            (self.failure_email_template,) = load_jinja2_templates(
+                self.config.email_template_dir,
+                [self.config.email_registration_template_failure_html],
+            )
+
+        if self.config.threepid_behaviour_email == ThreepidBehaviour.LOCAL:
+            (self.failure_email_template,) = load_jinja2_templates(
+                self.config.email_template_dir,
+                [self.config.email_registration_template_failure_html],
+            )
+
+    async def on_GET(self, request, medium):
         if medium != "email":
             raise SynapseError(
                 400, "This medium is currently not supported for registration"
             )
         if self.config.threepid_behaviour_email == ThreepidBehaviour.OFF:
             if self.config.local_threepid_handling_disabled_due_to_email_config:
-                logger.warn(
+                logger.warning(
                     "User registration via email has been disabled due to lack of email config"
                 )
             raise SynapseError(
@@ -268,14 +288,14 @@ class RegistrationSubmitTokenServlet(RestServlet):
         # Attempt to validate a 3PID session
         try:
             # Mark the session as valid
-            next_link = yield self.store.validate_threepid_session(
+            next_link = await self.store.validate_threepid_session(
                 sid, client_secret, token, self.clock.time_msec()
             )
 
             # Perform a 302 redirect if next_link is set
             if next_link:
                 if next_link.startswith("file:///"):
-                    logger.warn(
+                    logger.warning(
                         "Not redirecting to next_link as it is a local file: address"
                     )
                 else:
@@ -289,17 +309,11 @@ class RegistrationSubmitTokenServlet(RestServlet):
 
             request.setResponseCode(200)
         except ThreepidValidationError as e:
-            # Show a failure page with a reason
             request.setResponseCode(e.code)
 
             # Show a failure page with a reason
-            html_template, = load_jinja2_templates(
-                self.config.email_template_dir,
-                [self.config.email_registration_template_failure_html],
-            )
-
             template_vars = {"failure_reason": e.msg}
-            html = html_template.render(**template_vars)
+            html = self.failure_email_template.render(**template_vars)
 
         request.write(html.encode("utf-8"))
         finish_request(request)
@@ -332,15 +346,19 @@ class UsernameAvailabilityRestServlet(RestServlet):
             ),
         )
 
-    @defer.inlineCallbacks
-    def on_GET(self, request):
+    async def on_GET(self, request):
+        if not self.hs.config.enable_registration:
+            raise SynapseError(
+                403, "Registration has been disabled", errcode=Codes.FORBIDDEN
+            )
+
         ip = self.hs.get_ip_from_request(request)
         with self.ratelimiter.ratelimit(ip) as wait_deferred:
-            yield wait_deferred
+            await wait_deferred
 
             username = parse_string(request, "username", required=True)
 
-            yield self.registration_handler.check_username(username)
+            await self.registration_handler.check_username(username)
 
             return 200, {"available": True}
 
@@ -364,50 +382,46 @@ class RegisterRestServlet(RestServlet):
         self.room_member_handler = hs.get_room_member_handler()
         self.macaroon_gen = hs.get_macaroon_generator()
         self.ratelimiter = hs.get_registration_ratelimiter()
+        self.password_policy_handler = hs.get_password_policy_handler()
         self.clock = hs.get_clock()
 
+        self._registration_flows = _calculate_registration_flows(
+            hs.config, self.auth_handler
+        )
+
     @interactive_auth_handler
-    @defer.inlineCallbacks
-    def on_POST(self, request):
+    async def on_POST(self, request):
         body = parse_json_object_from_request(request)
 
         client_addr = request.getClientIP()
 
-        time_now = self.clock.time()
-
-        allowed, time_allowed = self.ratelimiter.can_do_action(
-            client_addr,
-            time_now_s=time_now,
-            rate_hz=self.hs.config.rc_registration.per_second,
-            burst_count=self.hs.config.rc_registration.burst_count,
-            update=False,
-        )
-
-        if not allowed:
-            raise LimitExceededError(
-                retry_after_ms=int(1000 * (time_allowed - time_now))
-            )
+        self.ratelimiter.ratelimit(client_addr, update=False)
 
         kind = b"user"
         if b"kind" in request.args:
             kind = request.args[b"kind"][0]
 
         if kind == b"guest":
-            ret = yield self._do_guest_registration(body, address=client_addr)
+            ret = await self._do_guest_registration(body, address=client_addr)
             return ret
         elif kind != b"user":
             raise UnrecognizedRequestError(
-                "Do not understand membership kind: %s" % (kind,)
+                "Do not understand membership kind: %s" % (kind.decode("utf8"),)
             )
 
         # we do basic sanity checks here because the auth layer will store these
         # in sessions. Pull out the username/password provided to us.
         if "password" in body:
-            if (
-                not isinstance(body["password"], string_types)
-                or len(body["password"]) > 512
-            ):
+            password = body.pop("password")
+            if not isinstance(password, string_types) or len(password) > 512:
                 raise SynapseError(400, "Invalid password")
+            self.password_policy_handler.validate_password(password)
+
+            # If the password is valid, hash it and store it back on the body.
+            # This ensures that only the hashed password is handled everywhere.
+            if "password_hash" in body:
+                raise SynapseError(400, "Unexpected property: password_hash")
+            body["password_hash"] = await self.auth_handler.hash(password)
 
         desired_username = None
         if "username" in body:
@@ -420,7 +434,7 @@ class RegisterRestServlet(RestServlet):
 
         appservice = None
         if self.auth.has_access_token(request):
-            appservice = yield self.auth.get_appservice_by_req(request)
+            appservice = await self.auth.get_appservice_by_req(request)
 
         # fork off as soon as possible for ASes which have completely
         # different registration flows to normal users
@@ -440,7 +454,7 @@ class RegisterRestServlet(RestServlet):
             access_token = self.auth.get_access_token_from_request(request)
 
             if isinstance(desired_username, string_types):
-                result = yield self._do_appservice_registration(
+                result = await self._do_appservice_registration(
                     desired_username, access_token, body
                 )
             return 200, result  # we throw for non 200 responses
@@ -460,12 +474,12 @@ class RegisterRestServlet(RestServlet):
 
         guest_access_token = body.get("guest_access_token", None)
 
-        if "initial_device_display_name" in body and "password" not in body:
+        if "initial_device_display_name" in body and "password_hash" not in body:
             # ignore 'initial_device_display_name' if sent without
             # a password to work around a client bug where it sent
             # the 'initial_device_display_name' param alone, wiping out
             # the original registration params
-            logger.warn("Ignoring initial_device_display_name without password")
+            logger.warning("Ignoring initial_device_display_name without password")
             del body["initial_device_display_name"]
 
         session_id = self.auth_handler.get_session_id(body)
@@ -475,80 +489,23 @@ class RegisterRestServlet(RestServlet):
             # registered a user for this session, so we could just return the
             # user here. We carry on and go through the auth checks though,
             # for paranoia.
-            registered_user_id = self.auth_handler.get_session_data(
+            registered_user_id = await self.auth_handler.get_session_data(
                 session_id, "registered_user_id", None
             )
 
         if desired_username is not None:
-            yield self.registration_handler.check_username(
+            await self.registration_handler.check_username(
                 desired_username,
                 guest_access_token=guest_access_token,
                 assigned_user_id=registered_user_id,
             )
 
-        # FIXME: need a better error than "no auth flow found" for scenarios
-        # where we required 3PID for registration but the user didn't give one
-        require_email = "email" in self.hs.config.registrations_require_3pid
-        require_msisdn = "msisdn" in self.hs.config.registrations_require_3pid
-
-        show_msisdn = True
-        if self.hs.config.disable_msisdn_registration:
-            show_msisdn = False
-            require_msisdn = False
-
-        flows = []
-        if self.hs.config.enable_registration_captcha:
-            # only support 3PIDless registration if no 3PIDs are required
-            if not require_email and not require_msisdn:
-                # Also add a dummy flow here, otherwise if a client completes
-                # recaptcha first we'll assume they were going for this flow
-                # and complete the request, when they could have been trying to
-                # complete one of the flows with email/msisdn auth.
-                flows.extend([[LoginType.RECAPTCHA, LoginType.DUMMY]])
-            # only support the email-only flow if we don't require MSISDN 3PIDs
-            if not require_msisdn:
-                flows.extend([[LoginType.RECAPTCHA, LoginType.EMAIL_IDENTITY]])
-
-            if show_msisdn:
-                # only support the MSISDN-only flow if we don't require email 3PIDs
-                if not require_email:
-                    flows.extend([[LoginType.RECAPTCHA, LoginType.MSISDN]])
-                # always let users provide both MSISDN & email
-                flows.extend(
-                    [[LoginType.RECAPTCHA, LoginType.MSISDN, LoginType.EMAIL_IDENTITY]]
-                )
-        else:
-            # only support 3PIDless registration if no 3PIDs are required
-            if not require_email and not require_msisdn:
-                flows.extend([[LoginType.DUMMY]])
-            # only support the email-only flow if we don't require MSISDN 3PIDs
-            if not require_msisdn:
-                flows.extend([[LoginType.EMAIL_IDENTITY]])
-
-            if show_msisdn:
-                # only support the MSISDN-only flow if we don't require email 3PIDs
-                if not require_email or require_msisdn:
-                    flows.extend([[LoginType.MSISDN]])
-                # always let users provide both MSISDN & email
-                flows.extend([[LoginType.MSISDN, LoginType.EMAIL_IDENTITY]])
-
-        # Append m.login.terms to all flows if we're requiring consent
-        if self.hs.config.user_consent_at_registration:
-            new_flows = []
-            for flow in flows:
-                inserted = False
-                # m.login.terms should go near the end but before msisdn or email auth
-                for i, stage in enumerate(flow):
-                    if stage == LoginType.EMAIL_IDENTITY or stage == LoginType.MSISDN:
-                        flow.insert(i, LoginType.TERMS)
-                        inserted = True
-                        break
-                if not inserted:
-                    flow.append(LoginType.TERMS)
-            flows.extend(new_flows)
-
-        auth_result, params, session_id = yield self.auth_handler.check_auth(
-            flows, body, self.hs.get_ip_from_request(request)
+        auth_result, params, session_id = await self.auth_handler.check_auth(
+            self._registration_flows,
+            request,
+            body,
+            self.hs.get_ip_from_request(request),
+            "register a new account",
         )
 
         # Check that we're not trying to register a denied 3pid.
@@ -579,11 +536,11 @@ class RegisterRestServlet(RestServlet):
             registered = False
         else:
             # NB: This may be from the auth handler and NOT from the POST
-            assert_params_in_dict(params, ["password"])
+            assert_params_in_dict(params, ["password_hash"])
 
             desired_username = params.get("username", None)
             guest_access_token = params.get("guest_access_token", None)
-            new_password = params.get("password", None)
+            new_password_hash = params.get("password_hash", None)
 
             if desired_username is not None:
                 desired_username = desired_username.lower()
@@ -603,7 +560,7 @@ class RegisterRestServlet(RestServlet):
                         medium = auth_result[login_type]["medium"]
                         address = auth_result[login_type]["address"]
 
-                        existing_user_id = yield self.store.get_user_id_by_threepid(
+                        existing_user_id = await self.store.get_user_id_by_threepid(
                             medium, address
                         )
 
@@ -614,9 +571,9 @@ class RegisterRestServlet(RestServlet):
                                 Codes.THREEPID_IN_USE,
                             )
 
-            registered_user_id = yield self.registration_handler.register_user(
+            registered_user_id = await self.registration_handler.register_user(
                 localpart=desired_username,
-                password=new_password,
+                password_hash=new_password_hash,
                 guest_access_token=guest_access_token,
                 threepid=threepid,
                 address=client_addr,
@@ -627,22 +584,22 @@ class RegisterRestServlet(RestServlet):
                 if is_threepid_reserved(
                     self.hs.config.mau_limits_reserved_threepids, threepid
                 ):
-                    yield self.store.upsert_monthly_active_user(registered_user_id)
+                    await self.store.upsert_monthly_active_user(registered_user_id)
 
             # remember that we've now registered that user account, and with
             #  what user ID (since the user may not have specified)
-            self.auth_handler.set_session_data(
+            await self.auth_handler.set_session_data(
                 session_id, "registered_user_id", registered_user_id
             )
 
             registered = True
 
-        return_dict = yield self._create_registration_details(
+        return_dict = await self._create_registration_details(
             registered_user_id, params
         )
 
         if registered:
-            yield self.registration_handler.post_registration_actions(
+            await self.registration_handler.post_registration_actions(
                 user_id=registered_user_id,
                 auth_result=auth_result,
                 access_token=return_dict.get("access_token"),
@@ -653,15 +610,13 @@ class RegisterRestServlet(RestServlet):
     def on_OPTIONS(self, _):
         return 200, {}
 
-    @defer.inlineCallbacks
-    def _do_appservice_registration(self, username, as_token, body):
-        user_id = yield self.registration_handler.appservice_register(
+    async def _do_appservice_registration(self, username, as_token, body):
+        user_id = await self.registration_handler.appservice_register(
             username, as_token
         )
-        return (yield self._create_registration_details(user_id, body))
+        return await self._create_registration_details(user_id, body)
 
-    @defer.inlineCallbacks
-    def _create_registration_details(self, user_id, params):
+    async def _create_registration_details(self, user_id, params):
         """Complete registration of newly-registered user
 
         Allocates device_id if one was not given; also creates access_token.
@@ -677,18 +632,17 @@ class RegisterRestServlet(RestServlet):
         if not params.get("inhibit_login", False):
             device_id = params.get("device_id")
             initial_display_name = params.get("initial_device_display_name")
-            device_id, access_token = yield self.registration_handler.register_device(
+            device_id, access_token = await self.registration_handler.register_device(
                 user_id, device_id, initial_display_name, is_guest=False
             )
 
             result.update({"access_token": access_token, "device_id": device_id})
         return result
 
-    @defer.inlineCallbacks
-    def _do_guest_registration(self, params, address=None):
+    async def _do_guest_registration(self, params, address=None):
         if not self.hs.config.allow_guest_access:
             raise SynapseError(403, "Guest access is disabled")
-        user_id = yield self.registration_handler.register_user(
+        user_id = await self.registration_handler.register_user(
             make_guest=True, address=address
         )
 
@@ -696,7 +650,7 @@ class RegisterRestServlet(RestServlet):
         # we have nowhere to store it.
         device_id = synapse.api.auth.GUEST_DEVICE_ID
         initial_display_name = params.get("initial_device_display_name")
-        device_id, access_token = yield self.registration_handler.register_device(
+        device_id, access_token = await self.registration_handler.register_device(
             user_id, device_id, initial_display_name, is_guest=True
         )
 
@@ -711,6 +665,83 @@ class RegisterRestServlet(RestServlet):
         )
 
 
+def _calculate_registration_flows(
+    # technically `config` has to provide *all* of these interfaces, not just one
+    config: Union[RegistrationConfig, ConsentConfig, CaptchaConfig],
+    auth_handler: AuthHandler,
+) -> List[List[str]]:
+    """Get a suitable flows list for registration
+
+    Args:
+        config: server configuration
+        auth_handler: authorization handler
+
+    Returns: a list of supported flows
+    """
+    # FIXME: need a better error than "no auth flow found" for scenarios
+    # where we required 3PID for registration but the user didn't give one
+    require_email = "email" in config.registrations_require_3pid
+    require_msisdn = "msisdn" in config.registrations_require_3pid
+
+    show_msisdn = True
+    show_email = True
+
+    if config.disable_msisdn_registration:
+        show_msisdn = False
+        require_msisdn = False
+
+    enabled_auth_types = auth_handler.get_enabled_auth_types()
+    if LoginType.EMAIL_IDENTITY not in enabled_auth_types:
+        show_email = False
+        if require_email:
+            raise ConfigError(
+                "Configuration requires email address at registration, but email "
+                "validation is not configured"
+            )
+
+    if LoginType.MSISDN not in enabled_auth_types:
+        show_msisdn = False
+        if require_msisdn:
+            raise ConfigError(
+                "Configuration requires msisdn at registration, but msisdn "
+                "validation is not configured"
+            )
+
+    flows = []
+
+    # only support 3PIDless registration if no 3PIDs are required
+    if not require_email and not require_msisdn:
+        # Add a dummy step here, otherwise if a client completes
+        # recaptcha first we'll assume they were going for this flow
+        # and complete the request, when they could have been trying to
+        # complete one of the flows with email/msisdn auth.
+        flows.append([LoginType.DUMMY])
+
+    # only support the email-only flow if we don't require MSISDN 3PIDs
+    if show_email and not require_msisdn:
+        flows.append([LoginType.EMAIL_IDENTITY])
+
+    # only support the MSISDN-only flow if we don't require email 3PIDs
+    if show_msisdn and not require_email:
+        flows.append([LoginType.MSISDN])
+
+    if show_email and show_msisdn:
+        # always let users provide both MSISDN & email
+        flows.append([LoginType.MSISDN, LoginType.EMAIL_IDENTITY])
+
+    # Prepend m.login.terms to all flows if we're requiring consent
+    if config.user_consent_at_registration:
+        for flow in flows:
+            flow.insert(0, LoginType.TERMS)
+
+    # Prepend recaptcha to all flows if we're requiring captcha
+    if config.enable_registration_captcha:
+        for flow in flows:
+            flow.insert(0, LoginType.RECAPTCHA)
+
+    return flows
+
+
 def register_servlets(hs, http_server):
     EmailRegisterRequestTokenRestServlet(hs).register(http_server)
     MsisdnRegisterRequestTokenRestServlet(hs).register(http_server)
diff --git a/synapse/rest/client/v2_alpha/relations.py b/synapse/rest/client/v2_alpha/relations.py
index 040b37c504..89002ffbff 100644
--- a/synapse/rest/client/v2_alpha/relations.py
+++ b/synapse/rest/client/v2_alpha/relations.py
@@ -21,8 +21,6 @@ any time to reflect changes in the MSC.
 
 import logging
 
-from twisted.internet import defer
-
 from synapse.api.constants import EventTypes, RelationTypes
 from synapse.api.errors import SynapseError
 from synapse.http.servlet import (
@@ -86,11 +84,10 @@ class RelationSendServlet(RestServlet):
             request, self.on_PUT_or_POST, request, *args, **kwargs
         )
 
-    @defer.inlineCallbacks
-    def on_PUT_or_POST(
+    async def on_PUT_or_POST(
         self, request, room_id, parent_id, relation_type, event_type, txn_id=None
     ):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
 
         if event_type == EventTypes.Member:
             # Add relations to a membership is meaningless, so we just deny it
@@ -114,7 +111,7 @@ class RelationSendServlet(RestServlet):
             "sender": requester.user.to_string(),
         }
 
-        event = yield self.event_creation_handler.create_and_send_nonmember_event(
+        event, _ = await self.event_creation_handler.create_and_send_nonmember_event(
             requester, event_dict=event_dict, txn_id=txn_id
         )
 
@@ -140,17 +137,18 @@ class RelationPaginationServlet(RestServlet):
         self._event_serializer = hs.get_event_client_serializer()
         self.event_handler = hs.get_event_handler()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, room_id, parent_id, relation_type=None, event_type=None):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(
+        self, request, room_id, parent_id, relation_type=None, event_type=None
+    ):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
 
-        yield self.auth.check_in_room_or_world_readable(
-            room_id, requester.user.to_string()
+        await self.auth.check_user_in_room_or_world_readable(
+            room_id, requester.user.to_string(), allow_departed_users=True
         )
 
         # This gets the original event and checks that a) the event exists and
         # b) the user is allowed to view it.
-        event = yield self.event_handler.get_event(requester.user, room_id, parent_id)
+        event = await self.event_handler.get_event(requester.user, room_id, parent_id)
 
         limit = parse_integer(request, "limit", default=5)
         from_token = parse_string(request, "from")
@@ -167,7 +165,7 @@ class RelationPaginationServlet(RestServlet):
             if to_token:
                 to_token = RelationPaginationToken.from_string(to_token)
 
-            pagination_chunk = yield self.store.get_relations_for_event(
+            pagination_chunk = await self.store.get_relations_for_event(
                 event_id=parent_id,
                 relation_type=relation_type,
                 event_type=event_type,
@@ -176,7 +174,7 @@ class RelationPaginationServlet(RestServlet):
                 to_token=to_token,
             )
 
-        events = yield self.store.get_events_as_list(
+        events = await self.store.get_events_as_list(
             [c["event_id"] for c in pagination_chunk.chunk]
         )
 
@@ -184,13 +182,13 @@ class RelationPaginationServlet(RestServlet):
         # We set bundle_aggregations to False when retrieving the original
         # event because we want the content before relations were applied to
         # it.
-        original_event = yield self._event_serializer.serialize_event(
+        original_event = await self._event_serializer.serialize_event(
             event, now, bundle_aggregations=False
         )
         # Similarly, we don't allow relations to be applied to relations, so we
         # return the original relations without any aggregations on top of them
         # here.
-        events = yield self._event_serializer.serialize_events(
+        events = await self._event_serializer.serialize_events(
             events, now, bundle_aggregations=False
         )
 
@@ -232,17 +230,18 @@ class RelationAggregationPaginationServlet(RestServlet):
         self.store = hs.get_datastore()
         self.event_handler = hs.get_event_handler()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, room_id, parent_id, relation_type=None, event_type=None):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(
+        self, request, room_id, parent_id, relation_type=None, event_type=None
+    ):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
 
-        yield self.auth.check_in_room_or_world_readable(
-            room_id, requester.user.to_string()
+        await self.auth.check_user_in_room_or_world_readable(
+            room_id, requester.user.to_string(), allow_departed_users=True,
         )
 
         # This checks that a) the event exists and b) the user is allowed to
         # view it.
-        event = yield self.event_handler.get_event(requester.user, room_id, parent_id)
+        event = await self.event_handler.get_event(requester.user, room_id, parent_id)
 
         if relation_type not in (RelationTypes.ANNOTATION, None):
             raise SynapseError(400, "Relation type must be 'annotation'")
@@ -262,7 +261,7 @@ class RelationAggregationPaginationServlet(RestServlet):
             if to_token:
                 to_token = AggregationPaginationToken.from_string(to_token)
 
-            pagination_chunk = yield self.store.get_aggregation_groups_for_event(
+            pagination_chunk = await self.store.get_aggregation_groups_for_event(
                 event_id=parent_id,
                 event_type=event_type,
                 limit=limit,
@@ -311,17 +310,16 @@ class RelationAggregationGroupPaginationServlet(RestServlet):
         self._event_serializer = hs.get_event_client_serializer()
         self.event_handler = hs.get_event_handler()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, room_id, parent_id, relation_type, event_type, key):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request, room_id, parent_id, relation_type, event_type, key):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
 
-        yield self.auth.check_in_room_or_world_readable(
-            room_id, requester.user.to_string()
+        await self.auth.check_user_in_room_or_world_readable(
+            room_id, requester.user.to_string(), allow_departed_users=True,
         )
 
         # This checks that a) the event exists and b) the user is allowed to
         # view it.
-        yield self.event_handler.get_event(requester.user, room_id, parent_id)
+        await self.event_handler.get_event(requester.user, room_id, parent_id)
 
         if relation_type != RelationTypes.ANNOTATION:
             raise SynapseError(400, "Relation type must be 'annotation'")
@@ -336,7 +334,7 @@ class RelationAggregationGroupPaginationServlet(RestServlet):
         if to_token:
             to_token = RelationPaginationToken.from_string(to_token)
 
-        result = yield self.store.get_relations_for_event(
+        result = await self.store.get_relations_for_event(
             event_id=parent_id,
             relation_type=relation_type,
             event_type=event_type,
@@ -346,12 +344,12 @@ class RelationAggregationGroupPaginationServlet(RestServlet):
             to_token=to_token,
         )
 
-        events = yield self.store.get_events_as_list(
+        events = await self.store.get_events_as_list(
             [c["event_id"] for c in result.chunk]
         )
 
         now = self.clock.time_msec()
-        events = yield self._event_serializer.serialize_events(events, now)
+        events = await self._event_serializer.serialize_events(events, now)
 
         return_value = result.to_dict()
         return_value["chunk"] = events
diff --git a/synapse/rest/client/v2_alpha/report_event.py b/synapse/rest/client/v2_alpha/report_event.py
index e7449864cd..f067b5edac 100644
--- a/synapse/rest/client/v2_alpha/report_event.py
+++ b/synapse/rest/client/v2_alpha/report_event.py
@@ -18,8 +18,6 @@ import logging
 from six import string_types
 from six.moves import http_client
 
-from twisted.internet import defer
-
 from synapse.api.errors import Codes, SynapseError
 from synapse.http.servlet import (
     RestServlet,
@@ -42,9 +40,8 @@ class ReportEventRestServlet(RestServlet):
         self.clock = hs.get_clock()
         self.store = hs.get_datastore()
 
-    @defer.inlineCallbacks
-    def on_POST(self, request, room_id, event_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_POST(self, request, room_id, event_id):
+        requester = await self.auth.get_user_by_req(request)
         user_id = requester.user.to_string()
 
         body = parse_json_object_from_request(request)
@@ -63,7 +60,7 @@ class ReportEventRestServlet(RestServlet):
                 Codes.BAD_JSON,
             )
 
-        yield self.store.add_event_report(
+        await self.store.add_event_report(
             room_id=room_id,
             event_id=event_id,
             user_id=user_id,
diff --git a/synapse/rest/client/v2_alpha/room_keys.py b/synapse/rest/client/v2_alpha/room_keys.py
index df4f44cd36..59529707df 100644
--- a/synapse/rest/client/v2_alpha/room_keys.py
+++ b/synapse/rest/client/v2_alpha/room_keys.py
@@ -15,8 +15,6 @@
 
 import logging
 
-from twisted.internet import defer
-
 from synapse.api.errors import Codes, NotFoundError, SynapseError
 from synapse.http.servlet import (
     RestServlet,
@@ -43,8 +41,7 @@ class RoomKeysServlet(RestServlet):
         self.auth = hs.get_auth()
         self.e2e_room_keys_handler = hs.get_e2e_room_keys_handler()
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, room_id, session_id):
+    async def on_PUT(self, request, room_id, session_id):
         """
         Uploads one or more encrypted E2E room keys for backup purposes.
         room_id: the ID of the room the keys are for (optional)
@@ -123,7 +120,7 @@ class RoomKeysServlet(RestServlet):
             }
         }
         """
-        requester = yield self.auth.get_user_by_req(request, allow_guest=False)
+        requester = await self.auth.get_user_by_req(request, allow_guest=False)
         user_id = requester.user.to_string()
         body = parse_json_object_from_request(request)
         version = parse_string(request, "version")
@@ -134,11 +131,10 @@ class RoomKeysServlet(RestServlet):
         if room_id:
             body = {"rooms": {room_id: body}}
 
-        yield self.e2e_room_keys_handler.upload_room_keys(user_id, version, body)
-        return 200, {}
+        ret = await self.e2e_room_keys_handler.upload_room_keys(user_id, version, body)
+        return 200, ret
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, room_id, session_id):
+    async def on_GET(self, request, room_id, session_id):
         """
         Retrieves one or more encrypted E2E room keys for backup purposes.
         Symmetric with the PUT version of the API.
@@ -190,11 +186,11 @@ class RoomKeysServlet(RestServlet):
             }
         }
         """
-        requester = yield self.auth.get_user_by_req(request, allow_guest=False)
+        requester = await self.auth.get_user_by_req(request, allow_guest=False)
         user_id = requester.user.to_string()
-        version = parse_string(request, "version")
+        version = parse_string(request, "version", required=True)
 
-        room_keys = yield self.e2e_room_keys_handler.get_room_keys(
+        room_keys = await self.e2e_room_keys_handler.get_room_keys(
             user_id, version, room_id, session_id
         )
 
@@ -220,8 +216,7 @@ class RoomKeysServlet(RestServlet):
 
         return 200, room_keys
 
-    @defer.inlineCallbacks
-    def on_DELETE(self, request, room_id, session_id):
+    async def on_DELETE(self, request, room_id, session_id):
         """
         Deletes one or more encrypted E2E room keys for a user for backup purposes.
 
@@ -235,14 +230,14 @@ class RoomKeysServlet(RestServlet):
         the version must already have been created via the /change_secret API.
         """
 
-        requester = yield self.auth.get_user_by_req(request, allow_guest=False)
+        requester = await self.auth.get_user_by_req(request, allow_guest=False)
         user_id = requester.user.to_string()
         version = parse_string(request, "version")
 
-        yield self.e2e_room_keys_handler.delete_room_keys(
+        ret = await self.e2e_room_keys_handler.delete_room_keys(
             user_id, version, room_id, session_id
         )
-        return 200, {}
+        return 200, ret
 
 
 class RoomKeysNewVersionServlet(RestServlet):
@@ -257,8 +252,7 @@ class RoomKeysNewVersionServlet(RestServlet):
         self.auth = hs.get_auth()
         self.e2e_room_keys_handler = hs.get_e2e_room_keys_handler()
 
-    @defer.inlineCallbacks
-    def on_POST(self, request):
+    async def on_POST(self, request):
         """
         Create a new backup version for this user's room_keys with the given
         info.  The version is allocated by the server and returned to the user
@@ -288,11 +282,11 @@ class RoomKeysNewVersionServlet(RestServlet):
             "version": 12345
         }
         """
-        requester = yield self.auth.get_user_by_req(request, allow_guest=False)
+        requester = await self.auth.get_user_by_req(request, allow_guest=False)
         user_id = requester.user.to_string()
         info = parse_json_object_from_request(request)
 
-        new_version = yield self.e2e_room_keys_handler.create_version(user_id, info)
+        new_version = await self.e2e_room_keys_handler.create_version(user_id, info)
         return 200, {"version": new_version}
 
     # we deliberately don't have a PUT /version, as these things really should
@@ -311,8 +305,7 @@ class RoomKeysVersionServlet(RestServlet):
         self.auth = hs.get_auth()
         self.e2e_room_keys_handler = hs.get_e2e_room_keys_handler()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, version):
+    async def on_GET(self, request, version):
         """
         Retrieve the version information about a given version of the user's
         room_keys backup.  If the version part is missing, returns info about the
@@ -330,18 +323,17 @@ class RoomKeysVersionServlet(RestServlet):
             "auth_data": "dGhpcyBzaG91bGQgYWN0dWFsbHkgYmUgZW5jcnlwdGVkIGpzb24K"
         }
         """
-        requester = yield self.auth.get_user_by_req(request, allow_guest=False)
+        requester = await self.auth.get_user_by_req(request, allow_guest=False)
         user_id = requester.user.to_string()
 
         try:
-            info = yield self.e2e_room_keys_handler.get_version_info(user_id, version)
+            info = await self.e2e_room_keys_handler.get_version_info(user_id, version)
         except SynapseError as e:
             if e.code == 404:
                 raise SynapseError(404, "No backup found", Codes.NOT_FOUND)
         return 200, info
 
-    @defer.inlineCallbacks
-    def on_DELETE(self, request, version):
+    async def on_DELETE(self, request, version):
         """
         Delete the information about a given version of the user's
         room_keys backup.  If the version part is missing, deletes the most
@@ -354,14 +346,13 @@ class RoomKeysVersionServlet(RestServlet):
         if version is None:
             raise SynapseError(400, "No version specified to delete", Codes.NOT_FOUND)
 
-        requester = yield self.auth.get_user_by_req(request, allow_guest=False)
+        requester = await self.auth.get_user_by_req(request, allow_guest=False)
         user_id = requester.user.to_string()
 
-        yield self.e2e_room_keys_handler.delete_version(user_id, version)
+        await self.e2e_room_keys_handler.delete_version(user_id, version)
         return 200, {}
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, version):
+    async def on_PUT(self, request, version):
         """
         Update the information about a given version of the user's room_keys backup.
 
@@ -375,14 +366,14 @@ class RoomKeysVersionServlet(RestServlet):
                     "ed25519:something": "hijklmnop"
                 }
             },
-            "version": "42"
+            "version": "12345"
         }
 
         HTTP/1.1 200 OK
         Content-Type: application/json
         {}
         """
-        requester = yield self.auth.get_user_by_req(request, allow_guest=False)
+        requester = await self.auth.get_user_by_req(request, allow_guest=False)
         user_id = requester.user.to_string()
         info = parse_json_object_from_request(request)
 
@@ -391,7 +382,7 @@ class RoomKeysVersionServlet(RestServlet):
                 400, "No version specified to update", Codes.MISSING_PARAM
             )
 
-        yield self.e2e_room_keys_handler.update_version(user_id, version, info)
+        await self.e2e_room_keys_handler.update_version(user_id, version, info)
         return 200, {}
 
 
diff --git a/synapse/rest/client/v2_alpha/room_upgrade_rest_servlet.py b/synapse/rest/client/v2_alpha/room_upgrade_rest_servlet.py
index d2c3316eb7..f357015a70 100644
--- a/synapse/rest/client/v2_alpha/room_upgrade_rest_servlet.py
+++ b/synapse/rest/client/v2_alpha/room_upgrade_rest_servlet.py
@@ -15,8 +15,6 @@
 
 import logging
 
-from twisted.internet import defer
-
 from synapse.api.errors import Codes, SynapseError
 from synapse.api.room_versions import KNOWN_ROOM_VERSIONS
 from synapse.http.servlet import (
@@ -59,22 +57,22 @@ class RoomUpgradeRestServlet(RestServlet):
         self._room_creation_handler = hs.get_room_creation_handler()
         self._auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_POST(self, request, room_id):
-        requester = yield self._auth.get_user_by_req(request)
+    async def on_POST(self, request, room_id):
+        requester = await self._auth.get_user_by_req(request)
 
         content = parse_json_object_from_request(request)
         assert_params_in_dict(content, ("new_version",))
         new_version = content["new_version"]
 
-        if new_version not in KNOWN_ROOM_VERSIONS:
+        new_version = KNOWN_ROOM_VERSIONS.get(content["new_version"])
+        if new_version is None:
             raise SynapseError(
                 400,
                 "Your homeserver does not support this room version",
                 Codes.UNSUPPORTED_ROOM_VERSION,
             )
 
-        new_room_id = yield self._room_creation_handler.upgrade_room(
+        new_room_id = await self._room_creation_handler.upgrade_room(
             requester, room_id, new_version
         )
 
diff --git a/synapse/rest/client/v2_alpha/sendtodevice.py b/synapse/rest/client/v2_alpha/sendtodevice.py
index d90e52ed1a..db829f3098 100644
--- a/synapse/rest/client/v2_alpha/sendtodevice.py
+++ b/synapse/rest/client/v2_alpha/sendtodevice.py
@@ -14,8 +14,7 @@
 # limitations under the License.
 
 import logging
-
-from twisted.internet import defer
+from typing import Tuple
 
 from synapse.http import servlet
 from synapse.http.servlet import parse_json_object_from_request
@@ -51,19 +50,18 @@ class SendToDeviceRestServlet(servlet.RestServlet):
             request, self._put, request, message_type, txn_id
         )
 
-    @defer.inlineCallbacks
-    def _put(self, request, message_type, txn_id):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def _put(self, request, message_type, txn_id):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
 
         content = parse_json_object_from_request(request)
 
         sender_user_id = requester.user.to_string()
 
-        yield self.device_message_handler.send_device_message(
+        await self.device_message_handler.send_device_message(
             sender_user_id, message_type, content["messages"]
         )
 
-        response = (200, {})
+        response = (200, {})  # type: Tuple[int, dict]
         return response
 
 
diff --git a/synapse/rest/client/v2_alpha/sync.py b/synapse/rest/client/v2_alpha/sync.py
index c98c5a3802..8fa68dd37f 100644
--- a/synapse/rest/client/v2_alpha/sync.py
+++ b/synapse/rest/client/v2_alpha/sync.py
@@ -18,10 +18,8 @@ import logging
 
 from canonicaljson import json
 
-from twisted.internet import defer
-
 from synapse.api.constants import PresenceState
-from synapse.api.errors import SynapseError
+from synapse.api.errors import Codes, StoreError, SynapseError
 from synapse.api.filtering import DEFAULT_FILTER_COLLECTION, FilterCollection
 from synapse.events.utils import (
     format_event_for_client_v2_without_room_id,
@@ -74,7 +72,7 @@ class SyncRestServlet(RestServlet):
     """
 
     PATTERNS = client_patterns("/sync$")
-    ALLOWED_PRESENCE = set(["online", "offline", "unavailable"])
+    ALLOWED_PRESENCE = {"online", "offline", "unavailable"}
 
     def __init__(self, hs):
         super(SyncRestServlet, self).__init__()
@@ -87,8 +85,7 @@ class SyncRestServlet(RestServlet):
         self._server_notices_sender = hs.get_server_notices_sender()
         self._event_serializer = hs.get_event_client_serializer()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request):
+    async def on_GET(self, request):
         if b"from" in request.args:
             # /events used to use 'from', but /sync uses 'since'.
             # Lets be helpful and whine if we see a 'from'.
@@ -96,7 +93,7 @@ class SyncRestServlet(RestServlet):
                 400, "'from' is not a valid query parameter. Did you mean 'since'?"
             )
 
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
         user = requester.user
         device_id = requester.device_id
 
@@ -112,32 +109,44 @@ class SyncRestServlet(RestServlet):
         full_state = parse_boolean(request, "full_state", default=False)
 
         logger.debug(
-            "/sync: user=%r, timeout=%r, since=%r,"
-            " set_presence=%r, filter_id=%r, device_id=%r"
-            % (user, timeout, since, set_presence, filter_id, device_id)
+            "/sync: user=%r, timeout=%r, since=%r, "
+            "set_presence=%r, filter_id=%r, device_id=%r",
+            user,
+            timeout,
+            since,
+            set_presence,
+            filter_id,
+            device_id,
         )
 
         request_key = (user, timeout, since, filter_id, full_state, device_id)
 
-        if filter_id:
-            if filter_id.startswith("{"):
-                try:
-                    filter_object = json.loads(filter_id)
-                    set_timeline_upper_limit(
-                        filter_object, self.hs.config.filter_timeline_limit
-                    )
-                except Exception:
-                    raise SynapseError(400, "Invalid filter JSON")
-                self.filtering.check_valid_filter(filter_object)
-                filter = FilterCollection(filter_object)
-            else:
-                filter = yield self.filtering.get_user_filter(user.localpart, filter_id)
+        if filter_id is None:
+            filter_collection = DEFAULT_FILTER_COLLECTION
+        elif filter_id.startswith("{"):
+            try:
+                filter_object = json.loads(filter_id)
+                set_timeline_upper_limit(
+                    filter_object, self.hs.config.filter_timeline_limit
+                )
+            except Exception:
+                raise SynapseError(400, "Invalid filter JSON")
+            self.filtering.check_valid_filter(filter_object)
+            filter_collection = FilterCollection(filter_object)
         else:
-            filter = DEFAULT_FILTER_COLLECTION
+            try:
+                filter_collection = await self.filtering.get_user_filter(
+                    user.localpart, filter_id
+                )
+            except StoreError as err:
+                if err.code != 404:
+                    raise
+                # fix up the description and errcode to be more useful
+                raise SynapseError(400, "No such filter", errcode=Codes.INVALID_PARAM)
 
         sync_config = SyncConfig(
             user=user,
-            filter_collection=filter,
+            filter_collection=filter_collection,
             is_guest=requester.is_guest,
             request_key=request_key,
             device_id=device_id,
@@ -149,20 +158,20 @@ class SyncRestServlet(RestServlet):
             since_token = None
 
         # send any outstanding server notices to the user.
-        yield self._server_notices_sender.on_user_syncing(user.to_string())
+        await self._server_notices_sender.on_user_syncing(user.to_string())
 
         affect_presence = set_presence != PresenceState.OFFLINE
 
         if affect_presence:
-            yield self.presence_handler.set_state(
+            await self.presence_handler.set_state(
                 user, {"presence": set_presence}, True
             )
 
-        context = yield self.presence_handler.user_syncing(
+        context = await self.presence_handler.user_syncing(
             user.to_string(), affect_presence=affect_presence
         )
         with context:
-            sync_result = yield self.sync_handler.wait_for_sync_for_user(
+            sync_result = await self.sync_handler.wait_for_sync_for_user(
                 sync_config,
                 since_token=since_token,
                 timeout=timeout,
@@ -170,14 +179,13 @@ class SyncRestServlet(RestServlet):
             )
 
         time_now = self.clock.time_msec()
-        response_content = yield self.encode_response(
-            time_now, sync_result, requester.access_token_id, filter
+        response_content = await self.encode_response(
+            time_now, sync_result, requester.access_token_id, filter_collection
         )
 
         return 200, response_content
 
-    @defer.inlineCallbacks
-    def encode_response(self, time_now, sync_result, access_token_id, filter):
+    async def encode_response(self, time_now, sync_result, access_token_id, filter):
         if filter.event_format == "client":
             event_formatter = format_event_for_client_v2_without_room_id
         elif filter.event_format == "federation":
@@ -185,7 +193,7 @@ class SyncRestServlet(RestServlet):
         else:
             raise Exception("Unknown event format %s" % (filter.event_format,))
 
-        joined = yield self.encode_joined(
+        joined = await self.encode_joined(
             sync_result.joined,
             time_now,
             access_token_id,
@@ -193,11 +201,11 @@ class SyncRestServlet(RestServlet):
             event_formatter,
         )
 
-        invited = yield self.encode_invited(
+        invited = await self.encode_invited(
             sync_result.invited, time_now, access_token_id, event_formatter
         )
 
-        archived = yield self.encode_archived(
+        archived = await self.encode_archived(
             sync_result.archived,
             time_now,
             access_token_id,
@@ -238,8 +246,9 @@ class SyncRestServlet(RestServlet):
             ]
         }
 
-    @defer.inlineCallbacks
-    def encode_joined(self, rooms, time_now, token_id, event_fields, event_formatter):
+    async def encode_joined(
+        self, rooms, time_now, token_id, event_fields, event_formatter
+    ):
         """
         Encode the joined rooms in a sync result
 
@@ -260,7 +269,7 @@ class SyncRestServlet(RestServlet):
         """
         joined = {}
         for room in rooms:
-            joined[room.room_id] = yield self.encode_room(
+            joined[room.room_id] = await self.encode_room(
                 room,
                 time_now,
                 token_id,
@@ -271,8 +280,7 @@ class SyncRestServlet(RestServlet):
 
         return joined
 
-    @defer.inlineCallbacks
-    def encode_invited(self, rooms, time_now, token_id, event_formatter):
+    async def encode_invited(self, rooms, time_now, token_id, event_formatter):
         """
         Encode the invited rooms in a sync result
 
@@ -292,7 +300,7 @@ class SyncRestServlet(RestServlet):
         """
         invited = {}
         for room in rooms:
-            invite = yield self._event_serializer.serialize_event(
+            invite = await self._event_serializer.serialize_event(
                 room.invite,
                 time_now,
                 token_id=token_id,
@@ -307,8 +315,9 @@ class SyncRestServlet(RestServlet):
 
         return invited
 
-    @defer.inlineCallbacks
-    def encode_archived(self, rooms, time_now, token_id, event_fields, event_formatter):
+    async def encode_archived(
+        self, rooms, time_now, token_id, event_fields, event_formatter
+    ):
         """
         Encode the archived rooms in a sync result
 
@@ -329,7 +338,7 @@ class SyncRestServlet(RestServlet):
         """
         joined = {}
         for room in rooms:
-            joined[room.room_id] = yield self.encode_room(
+            joined[room.room_id] = await self.encode_room(
                 room,
                 time_now,
                 token_id,
@@ -340,8 +349,7 @@ class SyncRestServlet(RestServlet):
 
         return joined
 
-    @defer.inlineCallbacks
-    def encode_room(
+    async def encode_room(
         self, room, time_now, token_id, joined, only_fields, event_formatter
     ):
         """
@@ -382,15 +390,15 @@ class SyncRestServlet(RestServlet):
             # We've had bug reports that events were coming down under the
             # wrong room.
             if event.room_id != room.room_id:
-                logger.warn(
+                logger.warning(
                     "Event %r is under room %r instead of %r",
                     event.event_id,
                     room.room_id,
                     event.room_id,
                 )
 
-        serialized_state = yield serialize(state_events)
-        serialized_timeline = yield serialize(timeline_events)
+        serialized_state = await serialize(state_events)
+        serialized_timeline = await serialize(timeline_events)
 
         account_data = room.account_data
 
diff --git a/synapse/rest/client/v2_alpha/tags.py b/synapse/rest/client/v2_alpha/tags.py
index 3b555669a0..a3f12e8a77 100644
--- a/synapse/rest/client/v2_alpha/tags.py
+++ b/synapse/rest/client/v2_alpha/tags.py
@@ -15,8 +15,6 @@
 
 import logging
 
-from twisted.internet import defer
-
 from synapse.api.errors import AuthError
 from synapse.http.servlet import RestServlet, parse_json_object_from_request
 
@@ -37,13 +35,12 @@ class TagListServlet(RestServlet):
         self.auth = hs.get_auth()
         self.store = hs.get_datastore()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, user_id, room_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_GET(self, request, user_id, room_id):
+        requester = await self.auth.get_user_by_req(request)
         if user_id != requester.user.to_string():
             raise AuthError(403, "Cannot get tags for other users.")
 
-        tags = yield self.store.get_tags_for_room(user_id, room_id)
+        tags = await self.store.get_tags_for_room(user_id, room_id)
 
         return 200, {"tags": tags}
 
@@ -64,27 +61,25 @@ class TagServlet(RestServlet):
         self.store = hs.get_datastore()
         self.notifier = hs.get_notifier()
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, user_id, room_id, tag):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_PUT(self, request, user_id, room_id, tag):
+        requester = await self.auth.get_user_by_req(request)
         if user_id != requester.user.to_string():
             raise AuthError(403, "Cannot add tags for other users.")
 
         body = parse_json_object_from_request(request)
 
-        max_id = yield self.store.add_tag_to_room(user_id, room_id, tag, body)
+        max_id = await self.store.add_tag_to_room(user_id, room_id, tag, body)
 
         self.notifier.on_new_event("account_data_key", max_id, users=[user_id])
 
         return 200, {}
 
-    @defer.inlineCallbacks
-    def on_DELETE(self, request, user_id, room_id, tag):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_DELETE(self, request, user_id, room_id, tag):
+        requester = await self.auth.get_user_by_req(request)
         if user_id != requester.user.to_string():
             raise AuthError(403, "Cannot add tags for other users.")
 
-        max_id = yield self.store.remove_tag_from_room(user_id, room_id, tag)
+        max_id = await self.store.remove_tag_from_room(user_id, room_id, tag)
 
         self.notifier.on_new_event("account_data_key", max_id, users=[user_id])
 
diff --git a/synapse/rest/client/v2_alpha/thirdparty.py b/synapse/rest/client/v2_alpha/thirdparty.py
index 2e8d672471..23709960ad 100644
--- a/synapse/rest/client/v2_alpha/thirdparty.py
+++ b/synapse/rest/client/v2_alpha/thirdparty.py
@@ -16,8 +16,6 @@
 
 import logging
 
-from twisted.internet import defer
-
 from synapse.api.constants import ThirdPartyEntityKind
 from synapse.http.servlet import RestServlet
 
@@ -35,11 +33,10 @@ class ThirdPartyProtocolsServlet(RestServlet):
         self.auth = hs.get_auth()
         self.appservice_handler = hs.get_application_service_handler()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request):
-        yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request):
+        await self.auth.get_user_by_req(request, allow_guest=True)
 
-        protocols = yield self.appservice_handler.get_3pe_protocols()
+        protocols = await self.appservice_handler.get_3pe_protocols()
         return 200, protocols
 
 
@@ -52,11 +49,10 @@ class ThirdPartyProtocolServlet(RestServlet):
         self.auth = hs.get_auth()
         self.appservice_handler = hs.get_application_service_handler()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, protocol):
-        yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request, protocol):
+        await self.auth.get_user_by_req(request, allow_guest=True)
 
-        protocols = yield self.appservice_handler.get_3pe_protocols(
+        protocols = await self.appservice_handler.get_3pe_protocols(
             only_protocol=protocol
         )
         if protocol in protocols:
@@ -74,14 +70,13 @@ class ThirdPartyUserServlet(RestServlet):
         self.auth = hs.get_auth()
         self.appservice_handler = hs.get_application_service_handler()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, protocol):
-        yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request, protocol):
+        await self.auth.get_user_by_req(request, allow_guest=True)
 
         fields = request.args
         fields.pop(b"access_token", None)
 
-        results = yield self.appservice_handler.query_3pe(
+        results = await self.appservice_handler.query_3pe(
             ThirdPartyEntityKind.USER, protocol, fields
         )
 
@@ -97,14 +92,13 @@ class ThirdPartyLocationServlet(RestServlet):
         self.auth = hs.get_auth()
         self.appservice_handler = hs.get_application_service_handler()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, protocol):
-        yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request, protocol):
+        await self.auth.get_user_by_req(request, allow_guest=True)
 
         fields = request.args
         fields.pop(b"access_token", None)
 
-        results = yield self.appservice_handler.query_3pe(
+        results = await self.appservice_handler.query_3pe(
             ThirdPartyEntityKind.LOCATION, protocol, fields
         )
 
diff --git a/synapse/rest/client/v2_alpha/tokenrefresh.py b/synapse/rest/client/v2_alpha/tokenrefresh.py
index 2da0f55811..83f3b6b70a 100644
--- a/synapse/rest/client/v2_alpha/tokenrefresh.py
+++ b/synapse/rest/client/v2_alpha/tokenrefresh.py
@@ -13,8 +13,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.internet import defer
-
 from synapse.api.errors import AuthError
 from synapse.http.servlet import RestServlet
 
@@ -32,8 +30,7 @@ class TokenRefreshRestServlet(RestServlet):
     def __init__(self, hs):
         super(TokenRefreshRestServlet, self).__init__()
 
-    @defer.inlineCallbacks
-    def on_POST(self, request):
+    async def on_POST(self, request):
         raise AuthError(403, "tokenrefresh is no longer supported.")
 
 
diff --git a/synapse/rest/client/v2_alpha/user_directory.py b/synapse/rest/client/v2_alpha/user_directory.py
index 2863affbab..bef91a2d3e 100644
--- a/synapse/rest/client/v2_alpha/user_directory.py
+++ b/synapse/rest/client/v2_alpha/user_directory.py
@@ -15,8 +15,6 @@
 
 import logging
 
-from twisted.internet import defer
-
 from synapse.api.errors import SynapseError
 from synapse.http.servlet import RestServlet, parse_json_object_from_request
 
@@ -38,8 +36,7 @@ class UserDirectorySearchRestServlet(RestServlet):
         self.auth = hs.get_auth()
         self.user_directory_handler = hs.get_user_directory_handler()
 
-    @defer.inlineCallbacks
-    def on_POST(self, request):
+    async def on_POST(self, request):
         """Searches for users in directory
 
         Returns:
@@ -56,7 +53,7 @@ class UserDirectorySearchRestServlet(RestServlet):
                     ]
                 }
         """
-        requester = yield self.auth.get_user_by_req(request, allow_guest=False)
+        requester = await self.auth.get_user_by_req(request, allow_guest=False)
         user_id = requester.user.to_string()
 
         if not self.hs.config.user_directory_search_enabled:
@@ -72,7 +69,7 @@ class UserDirectorySearchRestServlet(RestServlet):
         except Exception:
             raise SynapseError(400, "`search_term` is required field")
 
-        results = yield self.user_directory_handler.search_users(
+        results = await self.user_directory_handler.search_users(
             user_id, search_term, limit
         )
 
diff --git a/synapse/rest/client/versions.py b/synapse/rest/client/versions.py
index 0058b6b459..0d668df0b6 100644
--- a/synapse/rest/client/versions.py
+++ b/synapse/rest/client/versions.py
@@ -1,5 +1,8 @@
 # -*- coding: utf-8 -*-
 # Copyright 2016 OpenMarket Ltd
+# Copyright 2017 Vector Creations Ltd
+# Copyright 2018-2019 New Vector Ltd
+# Copyright 2019 The Matrix.org Foundation C.I.C.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -46,9 +49,18 @@ class VersionsRestServlet(RestServlet):
                     "r0.3.0",
                     "r0.4.0",
                     "r0.5.0",
+                    "r0.6.0",
                 ],
                 # as per MSC1497:
-                "unstable_features": {"m.lazy_load_members": True},
+                "unstable_features": {
+                    # Implements support for label-based filtering as described in
+                    # MSC2326.
+                    "org.matrix.label_based_filtering": True,
+                    # Implements support for cross signing as described in MSC1756
+                    "org.matrix.e2e_cross_signing": True,
+                    # Implements additional endpoints as described in MSC2432
+                    "org.matrix.msc2432": True,
+                },
             },
         )
 
diff --git a/synapse/rest/key/v2/remote_key_resource.py b/synapse/rest/key/v2/remote_key_resource.py
index 55580bc59e..ab671f7334 100644
--- a/synapse/rest/key/v2/remote_key_resource.py
+++ b/synapse/rest/key/v2/remote_key_resource.py
@@ -13,12 +13,11 @@
 # limitations under the License.
 
 import logging
+from typing import Dict, Set
 
 from canonicaljson import encode_canonical_json, json
 from signedjson.sign import sign_json
 
-from twisted.internet import defer
-
 from synapse.api.errors import Codes, SynapseError
 from synapse.crypto.keyring import ServerKeyFetcher
 from synapse.http.server import (
@@ -102,8 +101,8 @@ class RemoteKey(DirectServeResource):
     @wrap_json_request_handler
     async def _async_render_GET(self, request):
         if len(request.postpath) == 1:
-            server, = request.postpath
-            query = {server.decode("ascii"): {}}
+            (server,) = request.postpath
+            query = {server.decode("ascii"): {}}  # type: dict
         elif len(request.postpath) == 2:
             server, key_id = request.postpath
             minimum_valid_until_ts = parse_integer(request, "minimum_valid_until_ts")
@@ -124,8 +123,7 @@ class RemoteKey(DirectServeResource):
 
         await self.query_keys(request, query, query_remote_on_cache_miss=True)
 
-    @defer.inlineCallbacks
-    def query_keys(self, request, query, query_remote_on_cache_miss=False):
+    async def query_keys(self, request, query, query_remote_on_cache_miss=False):
         logger.info("Handling query for keys %r", query)
 
         store_queries = []
@@ -142,13 +140,13 @@ class RemoteKey(DirectServeResource):
             for key_id in key_ids:
                 store_queries.append((server_name, key_id, None))
 
-        cached = yield self.store.get_server_keys_json(store_queries)
+        cached = await self.store.get_server_keys_json(store_queries)
 
         json_results = set()
 
         time_now_ms = self.clock.time_msec()
 
-        cache_misses = dict()
+        cache_misses = {}  # type: Dict[str, Set[str]]
         for (server_name, key_id, from_server), results in cached.items():
             results = [(result["ts_added_ms"], result) for result in results]
 
@@ -214,8 +212,8 @@ class RemoteKey(DirectServeResource):
                     json_results.add(bytes(result["key_json"]))
 
         if cache_misses and query_remote_on_cache_miss:
-            yield self.fetcher.get_keys(cache_misses)
-            yield self.query_keys(request, query, query_remote_on_cache_miss=False)
+            await self.fetcher.get_keys(cache_misses)
+            await self.query_keys(request, query, query_remote_on_cache_miss=False)
         else:
             signed_keys = []
             for key_json in json_results:
diff --git a/synapse/rest/media/v0/__init__.py b/synapse/rest/media/v0/__init__.py
deleted file mode 100644
index e69de29bb2..0000000000
--- a/synapse/rest/media/v0/__init__.py
+++ /dev/null
diff --git a/synapse/rest/media/v0/content_repository.py b/synapse/rest/media/v0/content_repository.py
deleted file mode 100644
index 86884c0ef4..0000000000
--- a/synapse/rest/media/v0/content_repository.py
+++ /dev/null
@@ -1,103 +0,0 @@
-# -*- coding: utf-8 -*-
-# Copyright 2014-2016 OpenMarket Ltd
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-import base64
-import logging
-import os
-import re
-
-from canonicaljson import json
-
-from twisted.protocols.basic import FileSender
-from twisted.web import resource, server
-
-from synapse.api.errors import Codes, cs_error
-from synapse.http.server import finish_request, respond_with_json_bytes
-
-logger = logging.getLogger(__name__)
-
-
-class ContentRepoResource(resource.Resource):
-    """Provides file uploading and downloading.
-
-    Uploads are POSTed to wherever this Resource is linked to. This resource
-    returns a "content token" which can be used to GET this content again. The
-    token is typically a path, but it may not be. Tokens can expire, be
-    one-time uses, etc.
-
-    In this case, the token is a path to the file and contains 3 interesting
-    sections:
-        - User ID base64d (for namespacing content to each user)
-        - random 24 char string
-        - Content type base64d (so we can return it when clients GET it)
-
-    """
-
-    isLeaf = True
-
-    def __init__(self, hs, directory):
-        resource.Resource.__init__(self)
-        self.hs = hs
-        self.directory = directory
-
-    def render_GET(self, request):
-        # no auth here on purpose, to allow anyone to view, even across home
-        # servers.
-
-        # TODO: A little crude here, we could do this better.
-        filename = request.path.decode("ascii").split("/")[-1]
-        # be paranoid
-        filename = re.sub("[^0-9A-z.-_]", "", filename)
-
-        file_path = self.directory + "/" + filename
-
-        logger.debug("Searching for %s", file_path)
-
-        if os.path.isfile(file_path):
-            # filename has the content type
-            base64_contentype = filename.split(".")[1]
-            content_type = base64.urlsafe_b64decode(base64_contentype)
-            logger.info("Sending file %s", file_path)
-            f = open(file_path, "rb")
-            request.setHeader("Content-Type", content_type)
-
-            # cache for at least a day.
-            # XXX: we might want to turn this off for data we don't want to
-            # recommend caching as it's sensitive or private - or at least
-            # select private. don't bother setting Expires as all our matrix
-            # clients are smart enough to be happy with Cache-Control (right?)
-            request.setHeader(b"Cache-Control", b"public,max-age=86400,s-maxage=86400")
-
-            d = FileSender().beginFileTransfer(f, request)
-
-            # after the file has been sent, clean up and finish the request
-            def cbFinished(ignored):
-                f.close()
-                finish_request(request)
-
-            d.addCallback(cbFinished)
-        else:
-            respond_with_json_bytes(
-                request,
-                404,
-                json.dumps(cs_error("Not found", code=Codes.NOT_FOUND)),
-                send_cors=True,
-            )
-
-        return server.NOT_DONE_YET
-
-    def render_OPTIONS(self, request):
-        respond_with_json_bytes(request, 200, {}, send_cors=True)
-        return server.NOT_DONE_YET
diff --git a/synapse/rest/media/v1/_base.py b/synapse/rest/media/v1/_base.py
index 5fefee4dde..3689777266 100644
--- a/synapse/rest/media/v1/_base.py
+++ b/synapse/rest/media/v1/_base.py
@@ -17,7 +17,6 @@
 import logging
 import os
 
-from six import PY3
 from six.moves import urllib
 
 from twisted.internet import defer
@@ -30,6 +29,22 @@ from synapse.util.stringutils import is_ascii
 
 logger = logging.getLogger(__name__)
 
+# list all text content types that will have the charset default to UTF-8 when
+# none is given
+TEXT_CONTENT_TYPES = [
+    "text/css",
+    "text/csv",
+    "text/html",
+    "text/calendar",
+    "text/plain",
+    "text/javascript",
+    "application/json",
+    "application/ld+json",
+    "application/rtf",
+    "image/svg+xml",
+    "text/xml",
+]
+
 
 def parse_media_id(request):
     try:
@@ -96,7 +111,14 @@ def add_file_headers(request, media_type, file_size, upload_name):
     def _quote(x):
         return urllib.parse.quote(x.encode("utf-8"))
 
-    request.setHeader(b"Content-Type", media_type.encode("UTF-8"))
+    # Default to a UTF-8 charset for text content types.
+    # ex, uses UTF-8 for 'text/css' but not 'text/css; charset=UTF-16'
+    if media_type.lower() in TEXT_CONTENT_TYPES:
+        content_type = media_type + "; charset=UTF-8"
+    else:
+        content_type = media_type
+
+    request.setHeader(b"Content-Type", content_type.encode("UTF-8"))
     if upload_name:
         # RFC6266 section 4.1 [1] defines both `filename` and `filename*`.
         #
@@ -135,27 +157,25 @@ def add_file_headers(request, media_type, file_size, upload_name):
 
 # separators as defined in RFC2616. SP and HT are handled separately.
 # see _can_encode_filename_as_token.
-_FILENAME_SEPARATOR_CHARS = set(
-    (
-        "(",
-        ")",
-        "<",
-        ">",
-        "@",
-        ",",
-        ";",
-        ":",
-        "\\",
-        '"',
-        "/",
-        "[",
-        "]",
-        "?",
-        "=",
-        "{",
-        "}",
-    )
-)
+_FILENAME_SEPARATOR_CHARS = {
+    "(",
+    ")",
+    "<",
+    ">",
+    "@",
+    ",",
+    ";",
+    ":",
+    "\\",
+    '"',
+    "/",
+    "[",
+    "]",
+    "?",
+    "=",
+    "{",
+    "}",
+}
 
 
 def _can_encode_filename_as_token(x):
@@ -195,7 +215,7 @@ def respond_with_responder(request, responder, media_type, file_size, upload_nam
         respond_404(request)
         return
 
-    logger.debug("Responding to media request with responder %s")
+    logger.debug("Responding to media request with responder %s", responder)
     add_file_headers(request, media_type, file_size, upload_name)
     try:
         with responder:
@@ -303,23 +323,15 @@ def get_filename_from_headers(headers):
             upload_name_utf8 = upload_name_utf8[7:]
             # We have a filename*= section. This MUST be ASCII, and any UTF-8
             # bytes are %-quoted.
-            if PY3:
-                try:
-                    # Once it is decoded, we can then unquote the %-encoded
-                    # parts strictly into a unicode string.
-                    upload_name = urllib.parse.unquote(
-                        upload_name_utf8.decode("ascii"), errors="strict"
-                    )
-                except UnicodeDecodeError:
-                    # Incorrect UTF-8.
-                    pass
-            else:
-                # On Python 2, we first unquote the %-encoded parts and then
-                # decode it strictly using UTF-8.
-                try:
-                    upload_name = urllib.parse.unquote(upload_name_utf8).decode("utf8")
-                except UnicodeDecodeError:
-                    pass
+            try:
+                # Once it is decoded, we can then unquote the %-encoded
+                # parts strictly into a unicode string.
+                upload_name = urllib.parse.unquote(
+                    upload_name_utf8.decode("ascii"), errors="strict"
+                )
+            except UnicodeDecodeError:
+                # Incorrect UTF-8.
+                pass
 
     # If there isn't check for an ascii name.
     if not upload_name:
diff --git a/synapse/rest/media/v1/download_resource.py b/synapse/rest/media/v1/download_resource.py
index 66a01559e1..24d3ae5bbc 100644
--- a/synapse/rest/media/v1/download_resource.py
+++ b/synapse/rest/media/v1/download_resource.py
@@ -50,6 +50,9 @@ class DownloadResource(DirectServeResource):
             b" media-src 'self';"
             b" object-src 'self';",
         )
+        request.setHeader(
+            b"Referrer-Policy", b"no-referrer",
+        )
         server_name, media_id, name = parse_media_id(request)
         if server_name == self.server_name:
             await self.media_repo.get_local_media(request, media_id, name)
diff --git a/synapse/rest/media/v1/media_repository.py b/synapse/rest/media/v1/media_repository.py
index b972e152a9..fd10d42f2f 100644
--- a/synapse/rest/media/v1/media_repository.py
+++ b/synapse/rest/media/v1/media_repository.py
@@ -18,12 +18,12 @@ import errno
 import logging
 import os
 import shutil
+from typing import Dict, Tuple
 
 from six import iteritems
 
 import twisted.internet.error
 import twisted.web.http
-from twisted.internet import defer
 from twisted.web.resource import Resource
 
 from synapse.api.errors import (
@@ -113,15 +113,14 @@ class MediaRepository(object):
             "update_recently_accessed_media", self._update_recently_accessed
         )
 
-    @defer.inlineCallbacks
-    def _update_recently_accessed(self):
+    async def _update_recently_accessed(self):
         remote_media = self.recently_accessed_remotes
         self.recently_accessed_remotes = set()
 
         local_media = self.recently_accessed_locals
         self.recently_accessed_locals = set()
 
-        yield self.store.update_cached_last_access_time(
+        await self.store.update_cached_last_access_time(
             local_media, remote_media, self.clock.time_msec()
         )
 
@@ -137,8 +136,7 @@ class MediaRepository(object):
         else:
             self.recently_accessed_locals.add(media_id)
 
-    @defer.inlineCallbacks
-    def create_content(
+    async def create_content(
         self, media_type, upload_name, content, content_length, auth_user
     ):
         """Store uploaded content for a local user and return the mxc URL
@@ -157,11 +155,11 @@ class MediaRepository(object):
 
         file_info = FileInfo(server_name=None, file_id=media_id)
 
-        fname = yield self.media_storage.store_file(content, file_info)
+        fname = await self.media_storage.store_file(content, file_info)
 
         logger.info("Stored local media in file %r", fname)
 
-        yield self.store.store_local_media(
+        await self.store.store_local_media(
             media_id=media_id,
             media_type=media_type,
             time_now_ms=self.clock.time_msec(),
@@ -170,12 +168,11 @@ class MediaRepository(object):
             user_id=auth_user,
         )
 
-        yield self._generate_thumbnails(None, media_id, media_id, media_type)
+        await self._generate_thumbnails(None, media_id, media_id, media_type)
 
         return "mxc://%s/%s" % (self.server_name, media_id)
 
-    @defer.inlineCallbacks
-    def get_local_media(self, request, media_id, name):
+    async def get_local_media(self, request, media_id, name):
         """Responds to reqests for local media, if exists, or returns 404.
 
         Args:
@@ -189,7 +186,7 @@ class MediaRepository(object):
             Deferred: Resolves once a response has successfully been written
                 to request
         """
-        media_info = yield self.store.get_local_media(media_id)
+        media_info = await self.store.get_local_media(media_id)
         if not media_info or media_info["quarantined_by"]:
             respond_404(request)
             return
@@ -203,13 +200,12 @@ class MediaRepository(object):
 
         file_info = FileInfo(None, media_id, url_cache=url_cache)
 
-        responder = yield self.media_storage.fetch_media(file_info)
-        yield respond_with_responder(
+        responder = await self.media_storage.fetch_media(file_info)
+        await respond_with_responder(
             request, responder, media_type, media_length, upload_name
         )
 
-    @defer.inlineCallbacks
-    def get_remote_media(self, request, server_name, media_id, name):
+    async def get_remote_media(self, request, server_name, media_id, name):
         """Respond to requests for remote media.
 
         Args:
@@ -235,8 +231,8 @@ class MediaRepository(object):
         # We linearize here to ensure that we don't try and download remote
         # media multiple times concurrently
         key = (server_name, media_id)
-        with (yield self.remote_media_linearizer.queue(key)):
-            responder, media_info = yield self._get_remote_media_impl(
+        with (await self.remote_media_linearizer.queue(key)):
+            responder, media_info = await self._get_remote_media_impl(
                 server_name, media_id
             )
 
@@ -245,14 +241,13 @@ class MediaRepository(object):
             media_type = media_info["media_type"]
             media_length = media_info["media_length"]
             upload_name = name if name else media_info["upload_name"]
-            yield respond_with_responder(
+            await respond_with_responder(
                 request, responder, media_type, media_length, upload_name
             )
         else:
             respond_404(request)
 
-    @defer.inlineCallbacks
-    def get_remote_media_info(self, server_name, media_id):
+    async def get_remote_media_info(self, server_name, media_id):
         """Gets the media info associated with the remote file, downloading
         if necessary.
 
@@ -273,8 +268,8 @@ class MediaRepository(object):
         # We linearize here to ensure that we don't try and download remote
         # media multiple times concurrently
         key = (server_name, media_id)
-        with (yield self.remote_media_linearizer.queue(key)):
-            responder, media_info = yield self._get_remote_media_impl(
+        with (await self.remote_media_linearizer.queue(key)):
+            responder, media_info = await self._get_remote_media_impl(
                 server_name, media_id
             )
 
@@ -285,8 +280,7 @@ class MediaRepository(object):
 
         return media_info
 
-    @defer.inlineCallbacks
-    def _get_remote_media_impl(self, server_name, media_id):
+    async def _get_remote_media_impl(self, server_name, media_id):
         """Looks for media in local cache, if not there then attempt to
         download from remote server.
 
@@ -298,7 +292,7 @@ class MediaRepository(object):
         Returns:
             Deferred[(Responder, media_info)]
         """
-        media_info = yield self.store.get_cached_remote_media(server_name, media_id)
+        media_info = await self.store.get_cached_remote_media(server_name, media_id)
 
         # file_id is the ID we use to track the file locally. If we've already
         # seen the file then reuse the existing ID, otherwise genereate a new
@@ -316,19 +310,18 @@ class MediaRepository(object):
                 logger.info("Media is quarantined")
                 raise NotFoundError()
 
-            responder = yield self.media_storage.fetch_media(file_info)
+            responder = await self.media_storage.fetch_media(file_info)
             if responder:
                 return responder, media_info
 
         # Failed to find the file anywhere, lets download it.
 
-        media_info = yield self._download_remote_file(server_name, media_id, file_id)
+        media_info = await self._download_remote_file(server_name, media_id, file_id)
 
-        responder = yield self.media_storage.fetch_media(file_info)
+        responder = await self.media_storage.fetch_media(file_info)
         return responder, media_info
 
-    @defer.inlineCallbacks
-    def _download_remote_file(self, server_name, media_id, file_id):
+    async def _download_remote_file(self, server_name, media_id, file_id):
         """Attempt to download the remote file from the given server name,
         using the given file_id as the local id.
 
@@ -350,7 +343,7 @@ class MediaRepository(object):
                 ("/_matrix/media/v1/download", server_name, media_id)
             )
             try:
-                length, headers = yield self.client.get_file(
+                length, headers = await self.client.get_file(
                     server_name,
                     request_path,
                     output_stream=f,
@@ -363,7 +356,7 @@ class MediaRepository(object):
                     },
                 )
             except RequestSendFailed as e:
-                logger.warn(
+                logger.warning(
                     "Request failed fetching remote media %s/%s: %r",
                     server_name,
                     media_id,
@@ -372,7 +365,7 @@ class MediaRepository(object):
                 raise SynapseError(502, "Failed to fetch remote media")
 
             except HttpResponseException as e:
-                logger.warn(
+                logger.warning(
                     "HTTP error fetching remote media %s/%s: %s",
                     server_name,
                     media_id,
@@ -383,10 +376,12 @@ class MediaRepository(object):
                 raise SynapseError(502, "Failed to fetch remote media")
 
             except SynapseError:
-                logger.warn("Failed to fetch remote media %s/%s", server_name, media_id)
+                logger.warning(
+                    "Failed to fetch remote media %s/%s", server_name, media_id
+                )
                 raise
             except NotRetryingDestination:
-                logger.warn("Not retrying destination %r", server_name)
+                logger.warning("Not retrying destination %r", server_name)
                 raise SynapseError(502, "Failed to fetch remote media")
             except Exception:
                 logger.exception(
@@ -394,7 +389,7 @@ class MediaRepository(object):
                 )
                 raise SynapseError(502, "Failed to fetch remote media")
 
-            yield finish()
+            await finish()
 
         media_type = headers[b"Content-Type"][0].decode("ascii")
         upload_name = get_filename_from_headers(headers)
@@ -402,7 +397,7 @@ class MediaRepository(object):
 
         logger.info("Stored remote media in file %r", fname)
 
-        yield self.store.store_cached_remote_media(
+        await self.store.store_cached_remote_media(
             origin=server_name,
             media_id=media_id,
             media_type=media_type,
@@ -420,7 +415,7 @@ class MediaRepository(object):
             "filesystem_id": file_id,
         }
 
-        yield self._generate_thumbnails(server_name, media_id, file_id, media_type)
+        await self._generate_thumbnails(server_name, media_id, file_id, media_type)
 
         return media_info
 
@@ -455,16 +450,15 @@ class MediaRepository(object):
 
         return t_byte_source
 
-    @defer.inlineCallbacks
-    def generate_local_exact_thumbnail(
+    async def generate_local_exact_thumbnail(
         self, media_id, t_width, t_height, t_method, t_type, url_cache
     ):
-        input_path = yield self.media_storage.ensure_media_is_in_local_cache(
+        input_path = await self.media_storage.ensure_media_is_in_local_cache(
             FileInfo(None, media_id, url_cache=url_cache)
         )
 
         thumbnailer = Thumbnailer(input_path)
-        t_byte_source = yield defer_to_thread(
+        t_byte_source = await defer_to_thread(
             self.hs.get_reactor(),
             self._generate_thumbnail,
             thumbnailer,
@@ -487,7 +481,7 @@ class MediaRepository(object):
                     thumbnail_type=t_type,
                 )
 
-                output_path = yield self.media_storage.store_file(
+                output_path = await self.media_storage.store_file(
                     t_byte_source, file_info
                 )
             finally:
@@ -497,22 +491,21 @@ class MediaRepository(object):
 
             t_len = os.path.getsize(output_path)
 
-            yield self.store.store_local_thumbnail(
+            await self.store.store_local_thumbnail(
                 media_id, t_width, t_height, t_type, t_method, t_len
             )
 
             return output_path
 
-    @defer.inlineCallbacks
-    def generate_remote_exact_thumbnail(
+    async def generate_remote_exact_thumbnail(
         self, server_name, file_id, media_id, t_width, t_height, t_method, t_type
     ):
-        input_path = yield self.media_storage.ensure_media_is_in_local_cache(
+        input_path = await self.media_storage.ensure_media_is_in_local_cache(
             FileInfo(server_name, file_id, url_cache=False)
         )
 
         thumbnailer = Thumbnailer(input_path)
-        t_byte_source = yield defer_to_thread(
+        t_byte_source = await defer_to_thread(
             self.hs.get_reactor(),
             self._generate_thumbnail,
             thumbnailer,
@@ -534,7 +527,7 @@ class MediaRepository(object):
                     thumbnail_type=t_type,
                 )
 
-                output_path = yield self.media_storage.store_file(
+                output_path = await self.media_storage.store_file(
                     t_byte_source, file_info
                 )
             finally:
@@ -544,7 +537,7 @@ class MediaRepository(object):
 
             t_len = os.path.getsize(output_path)
 
-            yield self.store.store_remote_media_thumbnail(
+            await self.store.store_remote_media_thumbnail(
                 server_name,
                 media_id,
                 file_id,
@@ -557,8 +550,7 @@ class MediaRepository(object):
 
             return output_path
 
-    @defer.inlineCallbacks
-    def _generate_thumbnails(
+    async def _generate_thumbnails(
         self, server_name, media_id, file_id, media_type, url_cache=False
     ):
         """Generate and store thumbnails for an image.
@@ -579,7 +571,7 @@ class MediaRepository(object):
         if not requirements:
             return
 
-        input_path = yield self.media_storage.ensure_media_is_in_local_cache(
+        input_path = await self.media_storage.ensure_media_is_in_local_cache(
             FileInfo(server_name, file_id, url_cache=url_cache)
         )
 
@@ -597,13 +589,13 @@ class MediaRepository(object):
             return
 
         if thumbnailer.transpose_method is not None:
-            m_width, m_height = yield defer_to_thread(
+            m_width, m_height = await defer_to_thread(
                 self.hs.get_reactor(), thumbnailer.transpose
             )
 
         # We deduplicate the thumbnail sizes by ignoring the cropped versions if
         # they have the same dimensions of a scaled one.
-        thumbnails = {}
+        thumbnails = {}  # type: Dict[Tuple[int, int, str], str]
         for r_width, r_height, r_method, r_type in requirements:
             if r_method == "crop":
                 thumbnails.setdefault((r_width, r_height, r_type), r_method)
@@ -617,11 +609,11 @@ class MediaRepository(object):
         for (t_width, t_height, t_type), t_method in iteritems(thumbnails):
             # Generate the thumbnail
             if t_method == "crop":
-                t_byte_source = yield defer_to_thread(
+                t_byte_source = await defer_to_thread(
                     self.hs.get_reactor(), thumbnailer.crop, t_width, t_height, t_type
                 )
             elif t_method == "scale":
-                t_byte_source = yield defer_to_thread(
+                t_byte_source = await defer_to_thread(
                     self.hs.get_reactor(), thumbnailer.scale, t_width, t_height, t_type
                 )
             else:
@@ -643,7 +635,7 @@ class MediaRepository(object):
                     url_cache=url_cache,
                 )
 
-                output_path = yield self.media_storage.store_file(
+                output_path = await self.media_storage.store_file(
                     t_byte_source, file_info
                 )
             finally:
@@ -653,7 +645,7 @@ class MediaRepository(object):
 
             # Write to database
             if server_name:
-                yield self.store.store_remote_media_thumbnail(
+                await self.store.store_remote_media_thumbnail(
                     server_name,
                     media_id,
                     file_id,
@@ -664,15 +656,14 @@ class MediaRepository(object):
                     t_len,
                 )
             else:
-                yield self.store.store_local_thumbnail(
+                await self.store.store_local_thumbnail(
                     media_id, t_width, t_height, t_type, t_method, t_len
                 )
 
         return {"width": m_width, "height": m_height}
 
-    @defer.inlineCallbacks
-    def delete_old_remote_media(self, before_ts):
-        old_media = yield self.store.get_remote_media_before(before_ts)
+    async def delete_old_remote_media(self, before_ts):
+        old_media = await self.store.get_remote_media_before(before_ts)
 
         deleted = 0
 
@@ -686,12 +677,12 @@ class MediaRepository(object):
 
             # TODO: Should we delete from the backup store
 
-            with (yield self.remote_media_linearizer.queue(key)):
+            with (await self.remote_media_linearizer.queue(key)):
                 full_path = self.filepaths.remote_media_filepath(origin, file_id)
                 try:
                     os.remove(full_path)
                 except OSError as e:
-                    logger.warn("Failed to remove file: %r", full_path)
+                    logger.warning("Failed to remove file: %r", full_path)
                     if e.errno == errno.ENOENT:
                         pass
                     else:
@@ -702,7 +693,7 @@ class MediaRepository(object):
                 )
                 shutil.rmtree(thumbnail_dir, ignore_errors=True)
 
-                yield self.store.delete_remote_media(origin, media_id)
+                await self.store.delete_remote_media(origin, media_id)
                 deleted += 1
 
         return {"deleted": deleted}
diff --git a/synapse/rest/media/v1/media_storage.py b/synapse/rest/media/v1/media_storage.py
index 3b87717a5a..683a79c966 100644
--- a/synapse/rest/media/v1/media_storage.py
+++ b/synapse/rest/media/v1/media_storage.py
@@ -148,6 +148,7 @@ class MediaStorage(object):
         for provider in self.storage_providers:
             res = yield provider.fetch(path, file_info)
             if res:
+                logger.debug("Streaming %s from %s", path, provider)
                 return res
 
         return None
diff --git a/synapse/rest/media/v1/preview_url_resource.py b/synapse/rest/media/v1/preview_url_resource.py
index 7a56cd4b6c..f206605727 100644
--- a/synapse/rest/media/v1/preview_url_resource.py
+++ b/synapse/rest/media/v1/preview_url_resource.py
@@ -23,6 +23,7 @@ import re
 import shutil
 import sys
 import traceback
+from typing import Dict, Optional
 
 import six
 from six import string_types
@@ -56,6 +57,9 @@ logger = logging.getLogger(__name__)
 _charset_match = re.compile(br"<\s*meta[^>]*charset\s*=\s*([a-z0-9-]+)", flags=re.I)
 _content_type_match = re.compile(r'.*; *charset="?(.*?)"?(;|$)', flags=re.I)
 
+OG_TAG_NAME_MAXLEN = 50
+OG_TAG_VALUE_MAXLEN = 1000
+
 
 class PreviewUrlResource(DirectServeResource):
     isLeaf = True
@@ -74,12 +78,15 @@ class PreviewUrlResource(DirectServeResource):
             treq_args={"browser_like_redirects": True},
             ip_whitelist=hs.config.url_preview_ip_range_whitelist,
             ip_blacklist=hs.config.url_preview_ip_range_blacklist,
+            http_proxy=os.getenvb(b"http_proxy"),
+            https_proxy=os.getenvb(b"HTTPS_PROXY"),
         )
         self.media_repo = media_repo
         self.primary_base_path = media_repo.primary_base_path
         self.media_storage = media_storage
 
         self.url_preview_url_blacklist = hs.config.url_preview_url_blacklist
+        self.url_preview_accept_language = hs.config.url_preview_accept_language
 
         # memory cache mapping urls to an ObservableDeferred returning
         # JSON-encoded OG metadata
@@ -117,8 +124,10 @@ class PreviewUrlResource(DirectServeResource):
                 pattern = entry[attrib]
                 value = getattr(url_tuple, attrib)
                 logger.debug(
-                    ("Matching attrib '%s' with value '%s' against" " pattern '%s'")
-                    % (attrib, value, pattern)
+                    "Matching attrib '%s' with value '%s' against pattern '%s'",
+                    attrib,
+                    value,
+                    pattern,
                 )
 
                 if value is None:
@@ -134,7 +143,7 @@ class PreviewUrlResource(DirectServeResource):
                         match = False
                         continue
             if match:
-                logger.warn("URL %s blocked by url_blacklist entry %s", url, entry)
+                logger.warning("URL %s blocked by url_blacklist entry %s", url, entry)
                 raise SynapseError(
                     403, "URL blocked by url pattern blacklist entry", Codes.UNKNOWN
                 )
@@ -157,8 +166,7 @@ class PreviewUrlResource(DirectServeResource):
         og = await make_deferred_yieldable(defer.maybeDeferred(observable.observe))
         respond_with_json_bytes(request, 200, og, send_cors=True)
 
-    @defer.inlineCallbacks
-    def _do_preview(self, url, user, ts):
+    async def _do_preview(self, url, user, ts):
         """Check the db, and download the URL and build a preview
 
         Args:
@@ -167,11 +175,11 @@ class PreviewUrlResource(DirectServeResource):
             ts (int):
 
         Returns:
-            Deferred[str]: json-encoded og data
+            Deferred[bytes]: json-encoded og data
         """
         # check the URL cache in the DB (which will also provide us with
         # historical previews, if we have any)
-        cache_result = yield self.store.get_url_cache(url, ts)
+        cache_result = await self.store.get_url_cache(url, ts)
         if (
             cache_result
             and cache_result["expires_ts"] > ts
@@ -184,13 +192,13 @@ class PreviewUrlResource(DirectServeResource):
                 og = og.encode("utf8")
             return og
 
-        media_info = yield self._download_url(url, user)
+        media_info = await self._download_url(url, user)
 
-        logger.debug("got media_info of '%s'" % media_info)
+        logger.debug("got media_info of '%s'", media_info)
 
         if _is_media(media_info["media_type"]):
             file_id = media_info["filesystem_id"]
-            dims = yield self.media_repo._generate_thumbnails(
+            dims = await self.media_repo._generate_thumbnails(
                 None, file_id, file_id, media_info["media_type"], url_cache=True
             )
 
@@ -206,7 +214,7 @@ class PreviewUrlResource(DirectServeResource):
                 og["og:image:width"] = dims["width"]
                 og["og:image:height"] = dims["height"]
             else:
-                logger.warn("Couldn't get dims for %s" % url)
+                logger.warning("Couldn't get dims for %s" % url)
 
             # define our OG response for this media
         elif _is_html(media_info["media_type"]):
@@ -230,8 +238,8 @@ class PreviewUrlResource(DirectServeResource):
             # If we don't find a match, we'll look at the HTTP Content-Type, and
             # if that doesn't exist, we'll fall back to UTF-8.
             if not encoding:
-                match = _content_type_match.match(media_info["media_type"])
-                encoding = match.group(1) if match else "utf-8"
+                content_match = _content_type_match.match(media_info["media_type"])
+                encoding = content_match.group(1) if content_match else "utf-8"
 
             og = decode_and_calc_og(body, media_info["uri"], encoding)
 
@@ -240,21 +248,21 @@ class PreviewUrlResource(DirectServeResource):
             # request itself and benefit from the same caching etc.  But for now we
             # just rely on the caching on the master request to speed things up.
             if "og:image" in og and og["og:image"]:
-                image_info = yield self._download_url(
+                image_info = await self._download_url(
                     _rebase_url(og["og:image"], media_info["uri"]), user
                 )
 
                 if _is_media(image_info["media_type"]):
                     # TODO: make sure we don't choke on white-on-transparent images
                     file_id = image_info["filesystem_id"]
-                    dims = yield self.media_repo._generate_thumbnails(
+                    dims = await self.media_repo._generate_thumbnails(
                         None, file_id, file_id, image_info["media_type"], url_cache=True
                     )
                     if dims:
                         og["og:image:width"] = dims["width"]
                         og["og:image:height"] = dims["height"]
                     else:
-                        logger.warn("Couldn't get dims for %s" % og["og:image"])
+                        logger.warning("Couldn't get dims for %s", og["og:image"])
 
                     og["og:image"] = "mxc://%s/%s" % (
                         self.server_name,
@@ -265,15 +273,27 @@ class PreviewUrlResource(DirectServeResource):
                 else:
                     del og["og:image"]
         else:
-            logger.warn("Failed to find any OG data in %s", url)
+            logger.warning("Failed to find any OG data in %s", url)
             og = {}
 
-        logger.debug("Calculated OG for %s as %s" % (url, og))
+        # filter out any stupidly long values
+        keys_to_remove = []
+        for k, v in og.items():
+            # values can be numeric as well as strings, hence the cast to str
+            if len(k) > OG_TAG_NAME_MAXLEN or len(str(v)) > OG_TAG_VALUE_MAXLEN:
+                logger.warning(
+                    "Pruning overlong tag %s from OG data", k[:OG_TAG_NAME_MAXLEN]
+                )
+                keys_to_remove.append(k)
+        for k in keys_to_remove:
+            del og[k]
+
+        logger.debug("Calculated OG for %s as %s", url, og)
 
-        jsonog = json.dumps(og).encode("utf8")
+        jsonog = json.dumps(og)
 
         # store OG in history-aware DB cache
-        yield self.store.store_url_cache(
+        await self.store.store_url_cache(
             url,
             media_info["response_code"],
             media_info["etag"],
@@ -283,10 +303,9 @@ class PreviewUrlResource(DirectServeResource):
             media_info["created_ts"],
         )
 
-        return jsonog
+        return jsonog.encode("utf8")
 
-    @defer.inlineCallbacks
-    def _download_url(self, url, user):
+    async def _download_url(self, url, user):
         # TODO: we should probably honour robots.txt... except in practice
         # we're most likely being explicitly triggered by a human rather than a
         # bot, so are we really a robot?
@@ -297,9 +316,12 @@ class PreviewUrlResource(DirectServeResource):
 
         with self.media_storage.store_into_file(file_info) as (f, fname, finish):
             try:
-                logger.debug("Trying to get url '%s'" % url)
-                length, headers, uri, code = yield self.client.get_file(
-                    url, output_stream=f, max_size=self.max_spider_size
+                logger.debug("Trying to get preview for url '%s'", url)
+                length, headers, uri, code = await self.client.get_file(
+                    url,
+                    output_stream=f,
+                    max_size=self.max_spider_size,
+                    headers={"Accept-Language": self.url_preview_accept_language},
                 )
             except SynapseError:
                 # Pass SynapseErrors through directly, so that the servlet
@@ -317,7 +339,7 @@ class PreviewUrlResource(DirectServeResource):
                 )
             except Exception as e:
                 # FIXME: pass through 404s and other error messages nicely
-                logger.warn("Error downloading %s: %r", url, e)
+                logger.warning("Error downloading %s: %r", url, e)
 
                 raise SynapseError(
                     500,
@@ -325,7 +347,7 @@ class PreviewUrlResource(DirectServeResource):
                     % (traceback.format_exception_only(sys.exc_info()[0], e),),
                     Codes.UNKNOWN,
                 )
-            yield finish()
+            await finish()
 
         try:
             if b"Content-Type" in headers:
@@ -336,7 +358,7 @@ class PreviewUrlResource(DirectServeResource):
 
             download_name = get_filename_from_headers(headers)
 
-            yield self.store.store_local_media(
+            await self.store.store_local_media(
                 media_id=file_id,
                 media_type=media_type,
                 time_now_ms=self.clock.time_msec(),
@@ -373,22 +395,21 @@ class PreviewUrlResource(DirectServeResource):
             "expire_url_cache_data", self._expire_url_cache_data
         )
 
-    @defer.inlineCallbacks
-    def _expire_url_cache_data(self):
+    async def _expire_url_cache_data(self):
         """Clean up expired url cache content, media and thumbnails.
         """
         # TODO: Delete from backup media store
 
         now = self.clock.time_msec()
 
-        logger.info("Running url preview cache expiry")
+        logger.debug("Running url preview cache expiry")
 
-        if not (yield self.store.has_completed_background_updates()):
+        if not (await self.store.db.updates.has_completed_background_updates()):
             logger.info("Still running DB updates; skipping expiry")
             return
 
         # First we delete expired url cache entries
-        media_ids = yield self.store.get_expired_url_cache(now)
+        media_ids = await self.store.get_expired_url_cache(now)
 
         removed_media = []
         for media_id in media_ids:
@@ -398,7 +419,7 @@ class PreviewUrlResource(DirectServeResource):
             except OSError as e:
                 # If the path doesn't exist, meh
                 if e.errno != errno.ENOENT:
-                    logger.warn("Failed to remove media: %r: %s", media_id, e)
+                    logger.warning("Failed to remove media: %r: %s", media_id, e)
                     continue
 
             removed_media.append(media_id)
@@ -410,17 +431,19 @@ class PreviewUrlResource(DirectServeResource):
             except Exception:
                 pass
 
-        yield self.store.delete_url_cache(removed_media)
+        await self.store.delete_url_cache(removed_media)
 
         if removed_media:
             logger.info("Deleted %d entries from url cache", len(removed_media))
+        else:
+            logger.debug("No entries removed from url cache")
 
         # Now we delete old images associated with the url cache.
         # These may be cached for a bit on the client (i.e., they
         # may have a room open with a preview url thing open).
         # So we wait a couple of days before deleting, just in case.
         expire_before = now - 2 * 24 * 60 * 60 * 1000
-        media_ids = yield self.store.get_url_cache_media_before(expire_before)
+        media_ids = await self.store.get_url_cache_media_before(expire_before)
 
         removed_media = []
         for media_id in media_ids:
@@ -430,7 +453,7 @@ class PreviewUrlResource(DirectServeResource):
             except OSError as e:
                 # If the path doesn't exist, meh
                 if e.errno != errno.ENOENT:
-                    logger.warn("Failed to remove media: %r: %s", media_id, e)
+                    logger.warning("Failed to remove media: %r: %s", media_id, e)
                     continue
 
             try:
@@ -446,7 +469,7 @@ class PreviewUrlResource(DirectServeResource):
             except OSError as e:
                 # If the path doesn't exist, meh
                 if e.errno != errno.ENOENT:
-                    logger.warn("Failed to remove media: %r: %s", media_id, e)
+                    logger.warning("Failed to remove media: %r: %s", media_id, e)
                     continue
 
             removed_media.append(media_id)
@@ -458,9 +481,12 @@ class PreviewUrlResource(DirectServeResource):
             except Exception:
                 pass
 
-        yield self.store.delete_url_cache_media(removed_media)
+        await self.store.delete_url_cache_media(removed_media)
 
-        logger.info("Deleted %d media from url cache", len(removed_media))
+        if removed_media:
+            logger.info("Deleted %d media from url cache", len(removed_media))
+        else:
+            logger.debug("No media removed from url cache")
 
 
 def decode_and_calc_og(body, media_uri, request_encoding=None):
@@ -499,9 +525,13 @@ def _calc_og(tree, media_uri):
     # "og:video:height" : "720",
     # "og:video:secure_url": "https://www.youtube.com/v/LXDBoHyjmtw?version=3",
 
-    og = {}
+    og = {}  # type: Dict[str, Optional[str]]
     for tag in tree.xpath("//*/meta[starts-with(@property, 'og:')]"):
         if "content" in tag.attrib:
+            # if we've got more than 50 tags, someone is taking the piss
+            if len(og) >= 50:
+                logger.warning("Skipping OG for page with too many 'og:' tags")
+                return {}
             og[tag.attrib["property"]] = tag.attrib["content"]
 
     # TODO: grab article: meta tags too, e.g.:
diff --git a/synapse/rest/media/v1/storage_provider.py b/synapse/rest/media/v1/storage_provider.py
index 37687ea7f4..858680be26 100644
--- a/synapse/rest/media/v1/storage_provider.py
+++ b/synapse/rest/media/v1/storage_provider.py
@@ -77,6 +77,9 @@ class StorageProviderWrapper(StorageProvider):
         self.store_synchronous = store_synchronous
         self.store_remote = store_remote
 
+    def __str__(self):
+        return "StorageProviderWrapper[%s]" % (self.backend,)
+
     def store_file(self, path, file_info):
         if not file_info.server_name and not self.store_local:
             return defer.succeed(None)
@@ -114,6 +117,9 @@ class FileStorageProviderBackend(StorageProvider):
         self.cache_directory = hs.config.media_store_path
         self.base_directory = config
 
+    def __str__(self):
+        return "FileStorageProviderBackend[%s]" % (self.base_directory,)
+
     def store_file(self, path, file_info):
         """See StorageProvider.store_file"""
 
diff --git a/synapse/rest/media/v1/thumbnail_resource.py b/synapse/rest/media/v1/thumbnail_resource.py
index 08329884ac..0b87220234 100644
--- a/synapse/rest/media/v1/thumbnail_resource.py
+++ b/synapse/rest/media/v1/thumbnail_resource.py
@@ -16,8 +16,6 @@
 
 import logging
 
-from twisted.internet import defer
-
 from synapse.http.server import (
     DirectServeResource,
     set_cors_headers,
@@ -79,11 +77,10 @@ class ThumbnailResource(DirectServeResource):
                 )
             self.media_repo.mark_recently_accessed(server_name, media_id)
 
-    @defer.inlineCallbacks
-    def _respond_local_thumbnail(
+    async def _respond_local_thumbnail(
         self, request, media_id, width, height, method, m_type
     ):
-        media_info = yield self.store.get_local_media(media_id)
+        media_info = await self.store.get_local_media(media_id)
 
         if not media_info:
             respond_404(request)
@@ -93,7 +90,7 @@ class ThumbnailResource(DirectServeResource):
             respond_404(request)
             return
 
-        thumbnail_infos = yield self.store.get_local_media_thumbnails(media_id)
+        thumbnail_infos = await self.store.get_local_media_thumbnails(media_id)
 
         if thumbnail_infos:
             thumbnail_info = self._select_thumbnail(
@@ -114,14 +111,13 @@ class ThumbnailResource(DirectServeResource):
             t_type = file_info.thumbnail_type
             t_length = thumbnail_info["thumbnail_length"]
 
-            responder = yield self.media_storage.fetch_media(file_info)
-            yield respond_with_responder(request, responder, t_type, t_length)
+            responder = await self.media_storage.fetch_media(file_info)
+            await respond_with_responder(request, responder, t_type, t_length)
         else:
             logger.info("Couldn't find any generated thumbnails")
             respond_404(request)
 
-    @defer.inlineCallbacks
-    def _select_or_generate_local_thumbnail(
+    async def _select_or_generate_local_thumbnail(
         self,
         request,
         media_id,
@@ -130,7 +126,7 @@ class ThumbnailResource(DirectServeResource):
         desired_method,
         desired_type,
     ):
-        media_info = yield self.store.get_local_media(media_id)
+        media_info = await self.store.get_local_media(media_id)
 
         if not media_info:
             respond_404(request)
@@ -140,7 +136,7 @@ class ThumbnailResource(DirectServeResource):
             respond_404(request)
             return
 
-        thumbnail_infos = yield self.store.get_local_media_thumbnails(media_id)
+        thumbnail_infos = await self.store.get_local_media_thumbnails(media_id)
         for info in thumbnail_infos:
             t_w = info["thumbnail_width"] == desired_width
             t_h = info["thumbnail_height"] == desired_height
@@ -162,15 +158,15 @@ class ThumbnailResource(DirectServeResource):
                 t_type = file_info.thumbnail_type
                 t_length = info["thumbnail_length"]
 
-                responder = yield self.media_storage.fetch_media(file_info)
+                responder = await self.media_storage.fetch_media(file_info)
                 if responder:
-                    yield respond_with_responder(request, responder, t_type, t_length)
+                    await respond_with_responder(request, responder, t_type, t_length)
                     return
 
         logger.debug("We don't have a thumbnail of that size. Generating")
 
         # Okay, so we generate one.
-        file_path = yield self.media_repo.generate_local_exact_thumbnail(
+        file_path = await self.media_repo.generate_local_exact_thumbnail(
             media_id,
             desired_width,
             desired_height,
@@ -180,13 +176,12 @@ class ThumbnailResource(DirectServeResource):
         )
 
         if file_path:
-            yield respond_with_file(request, desired_type, file_path)
+            await respond_with_file(request, desired_type, file_path)
         else:
-            logger.warn("Failed to generate thumbnail")
+            logger.warning("Failed to generate thumbnail")
             respond_404(request)
 
-    @defer.inlineCallbacks
-    def _select_or_generate_remote_thumbnail(
+    async def _select_or_generate_remote_thumbnail(
         self,
         request,
         server_name,
@@ -196,9 +191,9 @@ class ThumbnailResource(DirectServeResource):
         desired_method,
         desired_type,
     ):
-        media_info = yield self.media_repo.get_remote_media_info(server_name, media_id)
+        media_info = await self.media_repo.get_remote_media_info(server_name, media_id)
 
-        thumbnail_infos = yield self.store.get_remote_media_thumbnails(
+        thumbnail_infos = await self.store.get_remote_media_thumbnails(
             server_name, media_id
         )
 
@@ -224,15 +219,15 @@ class ThumbnailResource(DirectServeResource):
                 t_type = file_info.thumbnail_type
                 t_length = info["thumbnail_length"]
 
-                responder = yield self.media_storage.fetch_media(file_info)
+                responder = await self.media_storage.fetch_media(file_info)
                 if responder:
-                    yield respond_with_responder(request, responder, t_type, t_length)
+                    await respond_with_responder(request, responder, t_type, t_length)
                     return
 
         logger.debug("We don't have a thumbnail of that size. Generating")
 
         # Okay, so we generate one.
-        file_path = yield self.media_repo.generate_remote_exact_thumbnail(
+        file_path = await self.media_repo.generate_remote_exact_thumbnail(
             server_name,
             file_id,
             media_id,
@@ -243,21 +238,20 @@ class ThumbnailResource(DirectServeResource):
         )
 
         if file_path:
-            yield respond_with_file(request, desired_type, file_path)
+            await respond_with_file(request, desired_type, file_path)
         else:
-            logger.warn("Failed to generate thumbnail")
+            logger.warning("Failed to generate thumbnail")
             respond_404(request)
 
-    @defer.inlineCallbacks
-    def _respond_remote_thumbnail(
+    async def _respond_remote_thumbnail(
         self, request, server_name, media_id, width, height, method, m_type
     ):
         # TODO: Don't download the whole remote file
         # We should proxy the thumbnail from the remote server instead of
         # downloading the remote file and generating our own thumbnails.
-        media_info = yield self.media_repo.get_remote_media_info(server_name, media_id)
+        media_info = await self.media_repo.get_remote_media_info(server_name, media_id)
 
-        thumbnail_infos = yield self.store.get_remote_media_thumbnails(
+        thumbnail_infos = await self.store.get_remote_media_thumbnails(
             server_name, media_id
         )
 
@@ -278,8 +272,8 @@ class ThumbnailResource(DirectServeResource):
             t_type = file_info.thumbnail_type
             t_length = thumbnail_info["thumbnail_length"]
 
-            responder = yield self.media_storage.fetch_media(file_info)
-            yield respond_with_responder(request, responder, t_type, t_length)
+            responder = await self.media_storage.fetch_media(file_info)
+            await respond_with_responder(request, responder, t_type, t_length)
         else:
             logger.info("Failed to find any generated thumbnails")
             respond_404(request)
@@ -296,8 +290,8 @@ class ThumbnailResource(DirectServeResource):
         d_h = desired_height
 
         if desired_method.lower() == "crop":
-            info_list = []
-            info_list2 = []
+            crop_info_list = []
+            crop_info_list2 = []
             for info in thumbnail_infos:
                 t_w = info["thumbnail_width"]
                 t_h = info["thumbnail_height"]
@@ -309,7 +303,7 @@ class ThumbnailResource(DirectServeResource):
                     type_quality = desired_type != info["thumbnail_type"]
                     length_quality = info["thumbnail_length"]
                     if t_w >= d_w or t_h >= d_h:
-                        info_list.append(
+                        crop_info_list.append(
                             (
                                 aspect_quality,
                                 min_quality,
@@ -320,7 +314,7 @@ class ThumbnailResource(DirectServeResource):
                             )
                         )
                     else:
-                        info_list2.append(
+                        crop_info_list2.append(
                             (
                                 aspect_quality,
                                 min_quality,
@@ -330,10 +324,10 @@ class ThumbnailResource(DirectServeResource):
                                 info,
                             )
                         )
-            if info_list:
-                return min(info_list)[-1]
+            if crop_info_list:
+                return min(crop_info_list)[-1]
             else:
-                return min(info_list2)[-1]
+                return min(crop_info_list2)[-1]
         else:
             info_list = []
             info_list2 = []
diff --git a/synapse/rest/media/v1/thumbnailer.py b/synapse/rest/media/v1/thumbnailer.py
index c995d7e043..c234ea7421 100644
--- a/synapse/rest/media/v1/thumbnailer.py
+++ b/synapse/rest/media/v1/thumbnailer.py
@@ -82,13 +82,21 @@ class Thumbnailer(object):
         else:
             return (max_height * self.width) // self.height, max_height
 
+    def _resize(self, width, height):
+        # 1-bit or 8-bit color palette images need converting to RGB
+        # otherwise they will be scaled using nearest neighbour which
+        # looks awful
+        if self.image.mode in ["1", "P"]:
+            self.image = self.image.convert("RGB")
+        return self.image.resize((width, height), Image.ANTIALIAS)
+
     def scale(self, width, height, output_type):
         """Rescales the image to the given dimensions.
 
         Returns:
             BytesIO: the bytes of the encoded image ready to be written to disk
         """
-        scaled = self.image.resize((width, height), Image.ANTIALIAS)
+        scaled = self._resize(width, height)
         return self._encode_image(scaled, output_type)
 
     def crop(self, width, height, output_type):
@@ -107,13 +115,13 @@ class Thumbnailer(object):
         """
         if width * self.height > height * self.width:
             scaled_height = (width * self.height) // self.width
-            scaled_image = self.image.resize((width, scaled_height), Image.ANTIALIAS)
+            scaled_image = self._resize(width, scaled_height)
             crop_top = (scaled_height - height) // 2
             crop_bottom = height + crop_top
             cropped = scaled_image.crop((0, crop_top, width, crop_bottom))
         else:
             scaled_width = (height * self.width) // self.height
-            scaled_image = self.image.resize((scaled_width, height), Image.ANTIALIAS)
+            scaled_image = self._resize(scaled_width, height)
             crop_left = (scaled_width - width) // 2
             crop_right = width + crop_left
             cropped = scaled_image.crop((crop_left, 0, crop_right, height))
@@ -121,5 +129,8 @@ class Thumbnailer(object):
 
     def _encode_image(self, output_image, output_type):
         output_bytes_io = BytesIO()
-        output_image.save(output_bytes_io, self.FORMATS[output_type], quality=80)
+        fmt = self.FORMATS[output_type]
+        if fmt == "JPEG":
+            output_image = output_image.convert("RGB")
+        output_image.save(output_bytes_io, fmt, quality=80)
         return output_bytes_io
diff --git a/synapse/rest/media/v1/upload_resource.py b/synapse/rest/media/v1/upload_resource.py
index 5d76bbdf68..83d005812d 100644
--- a/synapse/rest/media/v1/upload_resource.py
+++ b/synapse/rest/media/v1/upload_resource.py
@@ -17,7 +17,7 @@ import logging
 
 from twisted.web.server import NOT_DONE_YET
 
-from synapse.api.errors import SynapseError
+from synapse.api.errors import Codes, SynapseError
 from synapse.http.server import (
     DirectServeResource,
     respond_with_json,
@@ -56,7 +56,11 @@ class UploadResource(DirectServeResource):
         if content_length is None:
             raise SynapseError(msg="Request must specify a Content-Length", code=400)
         if int(content_length) > self.max_upload_size:
-            raise SynapseError(msg="Upload request body is too large", code=413)
+            raise SynapseError(
+                msg="Upload request body is too large",
+                code=413,
+                errcode=Codes.TOO_LARGE,
+            )
 
         upload_name = parse_string(request, b"filename", encoding=None)
         if upload_name:
diff --git a/synapse/rest/oidc/__init__.py b/synapse/rest/oidc/__init__.py
new file mode 100644
index 0000000000..d958dd65bb
--- /dev/null
+++ b/synapse/rest/oidc/__init__.py
@@ -0,0 +1,27 @@
+# -*- coding: utf-8 -*-
+# Copyright 2020 Quentin Gliech
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import logging
+
+from twisted.web.resource import Resource
+
+from synapse.rest.oidc.callback_resource import OIDCCallbackResource
+
+logger = logging.getLogger(__name__)
+
+
+class OIDCResource(Resource):
+    def __init__(self, hs):
+        Resource.__init__(self)
+        self.putChild(b"callback", OIDCCallbackResource(hs))
diff --git a/synapse/rest/oidc/callback_resource.py b/synapse/rest/oidc/callback_resource.py
new file mode 100644
index 0000000000..c03194f001
--- /dev/null
+++ b/synapse/rest/oidc/callback_resource.py
@@ -0,0 +1,31 @@
+# -*- coding: utf-8 -*-
+# Copyright 2020 Quentin Gliech
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import logging
+
+from synapse.http.server import DirectServeResource, wrap_html_request_handler
+
+logger = logging.getLogger(__name__)
+
+
+class OIDCCallbackResource(DirectServeResource):
+    isLeaf = 1
+
+    def __init__(self, hs):
+        super().__init__()
+        self._oidc_handler = hs.get_oidc_handler()
+
+    @wrap_html_request_handler
+    async def _async_render_GET(self, request):
+        return await self._oidc_handler.handle_oidc_callback(request)
diff --git a/synapse/rest/saml2/response_resource.py b/synapse/rest/saml2/response_resource.py
index 69ecc5e4b4..75e58043b4 100644
--- a/synapse/rest/saml2/response_resource.py
+++ b/synapse/rest/saml2/response_resource.py
@@ -13,8 +13,10 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+from twisted.python import failure
 
-from synapse.http.server import DirectServeResource, wrap_html_request_handler
+from synapse.api.errors import SynapseError
+from synapse.http.server import DirectServeResource, return_html_error
 
 
 class SAML2ResponseResource(DirectServeResource):
@@ -25,7 +27,21 @@ class SAML2ResponseResource(DirectServeResource):
     def __init__(self, hs):
         super().__init__()
         self._saml_handler = hs.get_saml_handler()
+        self._error_html_template = hs.config.saml2.saml2_error_html_template
+
+    async def _async_render_GET(self, request):
+        # We're not expecting any GET request on that resource if everything goes right,
+        # but some IdPs sometimes end up responding with a 302 redirect on this endpoint.
+        # In this case, just tell the user that something went wrong and they should
+        # try to authenticate again.
+        f = failure.Failure(
+            SynapseError(400, "Unexpected GET request on /saml2/authn_response")
+        )
+        return_html_error(f, request, self._error_html_template)
 
-    @wrap_html_request_handler
     async def _async_render_POST(self, request):
-        return await self._saml_handler.handle_saml_response(request)
+        try:
+            await self._saml_handler.handle_saml_response(request)
+        except Exception:
+            f = failure.Failure()
+            return_html_error(f, request, self._error_html_template)