Merge branch 'develop' into babolivier/message_retention

6 files changed, 736 insertions, 574 deletions

diff --git a/synapse/rest/admin/__init__.py b/synapse/rest/admin/__init__.py
index 5c2a2eb593..68a59a3424 100644
--- a/synapse/rest/admin/__init__.py
+++ b/synapse/rest/admin/__init__.py
@@ -14,62 +14,39 @@
 # 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
-
 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.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 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.util.async_helpers import maybe_awaitable
+from synapse.rest.admin.users import (
+    AccountValidityRenewServlet,
+    DeactivateAccountRestServlet,
+    GetUsersPaginatedRestServlet,
+    ResetPasswordRestServlet,
+    SearchUsersRestServlet,
+    UserAdminServlet,
+    UserRegisterServlet,
+    UsersRestServlet,
+    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>[^/]*)$")
-
-    def __init__(self, hs):
-        self.hs = hs
-        self.auth = hs.get_auth()
-        self.handlers = hs.get_handlers()
-
-    async def on_GET(self, request, user_id):
-        target_user = UserID.from_string(user_id)
-        await assert_requester_is_admin(self.auth, request)
-
-        if not self.hs.is_mine(target_user):
-            raise SynapseError(400, "Can only users a local user")
-
-        ret = await self.handlers.admin_handler.get_users()
-
-        return 200, ret
-
-
 class VersionServlet(RestServlet):
     PATTERNS = (re.compile("^/_synapse/admin/v1/server_version$"),)
 
@@ -83,159 +60,6 @@ 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}
-
-    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:
-            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 = await register.registration_handler.register_user(
-            localpart=body["username"].lower(),
-            password=body["password"],
-            admin=bool(admin),
-            user_type=user_type,
-        )
-
-        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 PurgeHistoryRestServlet(RestServlet):
     PATTERNS = historical_admin_path_patterns(
         "/purge_history/(?P<room_id>[^/]*)(/(?P<event_id>[^/]+))?"
@@ -342,369 +166,6 @@ 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()
-
-    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 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()
-
-    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 = 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)
-
-        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)
-                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,
-                )
-
-                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 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()
-
-    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"]
-
-        await 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()
-
-    async 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.
-        """
-        await 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 = await self.handlers.admin_handler.get_users_paginate(order, start, limit)
-        return 200, ret
-
-    async 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.
-        """
-        await 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 = await 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()
-
-    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.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()
-
-    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, {}
-
-
-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
-
-
 ########################################################################################
 #
 # please don't add more servlets here: this file is already long and unwieldy. Put
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/rooms.py b/synapse/rest/admin/rooms.py
new file mode 100644
index 0000000000..f7cc5e9be9
--- /dev/null
+++ b/synapse/rest/admin/rooms.py
@@ -0,0 +1,157 @@
+# -*- 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.constants import Membership
+from synapse.http.servlet import (
+    RestServlet,
+    assert_params_in_dict,
+    parse_json_object_from_request,
+)
+from synapse.rest.admin._base import (
+    assert_user_is_admin,
+    historical_admin_path_patterns,
+)
+from synapse.types import 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()
+
+    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 = 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)
+
+        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)
+                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,
+                )
+
+                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,
+            },
+        )
diff --git a/synapse/rest/admin/users.py b/synapse/rest/admin/users.py
index d5d124a0dc..58a83f93af 100644
--- a/synapse/rest/admin/users.py
+++ b/synapse/rest/admin/users.py
@@ -12,17 +12,419 @@
 # 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 synapse.api.errors import SynapseError
+from six import text_type
+from six.moves import http_client
+
+from synapse.api.constants import UserTypes
+from synapse.api.errors import Codes, 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 (
+    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.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.admin_handler.get_users()
+
+        return 200, ret
+
+
+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()
+
+    async 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.
+        """
+        await 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 = await self.handlers.admin_handler.get_users_paginate(order, start, limit)
+        return 200, ret
+
+    async 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.
+        """
+        await 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 = await self.handlers.admin_handler.get_users_paginate(order, start, limit)
+        return 200, 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.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}
+
+    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:
+            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 = await register.registration_handler.register_user(
+            localpart=body["username"].lower(),
+            password=body["password"],
+            admin=bool(admin),
+            user_type=user_type,
+        )
+
+        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._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"]
+
+        await self._set_password_handler.set_password(
+            target_user_id, new_password, 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.store = hs.get_datastore()
+        self.hs = hs
+        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.admin_handler.search_users(term)
+        return 200, ret
+
 
 class UserAdminServlet(RestServlet):
     """
diff --git a/synapse/rest/client/v1/login.py b/synapse/rest/client/v1/login.py
index 24a0ce74f2..19eb15003d 100644
--- a/synapse/rest/client/v1/login.py
+++ b/synapse/rest/client/v1/login.py
@@ -92,8 +92,11 @@ class LoginRestServlet(RestServlet):
         self.auth_handler = self.hs.get_auth_handler()
         self.registration_handler = hs.get_registration_handler()
         self.handlers = hs.get_handlers()
+        self._clock = hs.get_clock()
         self._well_known_builder = WellKnownBuilder(hs)
         self._address_ratelimiter = Ratelimiter()
+        self._account_ratelimiter = Ratelimiter()
+        self._failed_attempts_ratelimiter = Ratelimiter()
 
     def on_GET(self, request):
         flows = []
@@ -202,6 +205,16 @@ 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),
+                time_now_s=self._clock.time(),
+                rate_hz=self.hs.config.rc_login_failed_attempts.per_second,
+                burst_count=self.hs.config.rc_login_failed_attempts.burst_count,
+                update=False,
+            )
+
             # Check for login providers that support 3pid login types
             (
                 canonical_user_id,
@@ -211,7 +224,8 @@ class LoginRestServlet(RestServlet):
             )
             if canonical_user_id:
                 # Authentication through password provider and 3pid succeeded
-                result = yield self._register_device_with_callback(
+
+                result = yield self._complete_login(
                     canonical_user_id, login_submission, callback_3pid
                 )
                 return result
@@ -225,6 +239,21 @@ class LoginRestServlet(RestServlet):
                 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),
+                    time_now_s=self._clock.time(),
+                    rate_hz=self.hs.config.rc_login_failed_attempts.per_second,
+                    burst_count=self.hs.config.rc_login_failed_attempts.burst_count,
+                    update=True,
+                )
                 raise LoginError(403, "", errcode=Codes.FORBIDDEN)
 
             identifier = {"type": "m.id.user", "user": user_id}
@@ -236,29 +265,84 @@ 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(),
+            time_now_s=self._clock.time(),
+            rate_hz=self.hs.config.rc_login_failed_attempts.per_second,
+            burst_count=self.hs.config.rc_login_failed_attempts.burst_count,
+            update=False,
         )
 
-        result = yield self._register_device_with_callback(
+        try:
+            canonical_user_id, callback = yield 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(),
+                time_now_s=self._clock.time(),
+                rate_hz=self.hs.config.rc_login_failed_attempts.per_second,
+                burst_count=self.hs.config.rc_login_failed_attempts.burst_count,
+                update=True,
+            )
+            raise
+
+        result = yield 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.
+    def _complete_login(
+        self, user_id, login_submission, callback=None, create_non_existant_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_existant_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(),
+            time_now_s=self._clock.time(),
+            rate_hz=self.hs.config.rc_login_account.per_second,
+            burst_count=self.hs.config.rc_login_account.burst_count,
+            update=True,
+        )
+
+        if create_non_existant_users:
+            user_id = yield self.auth_handler.check_user_exists(user_id)
+            if not user_id:
+                user_id = yield self.registration_handler.register_user(
+                    localpart=UserID.from_string(user_id).localpart
+                )
+
         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(
@@ -285,7 +369,7 @@ class LoginRestServlet(RestServlet):
             token
         )
 
-        result = yield self._register_device_with_callback(user_id, login_submission)
+        result = yield self._complete_login(user_id, login_submission)
         return result
 
     @defer.inlineCallbacks
@@ -313,15 +397,8 @@ 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 = yield self._complete_login(
+            user_id, login_submission, create_non_existant_users=True
         )
         return result
 
diff --git a/synapse/rest/media/v1/preview_url_resource.py b/synapse/rest/media/v1/preview_url_resource.py
index 531d923f76..a23d6f5c75 100644
--- a/synapse/rest/media/v1/preview_url_resource.py
+++ b/synapse/rest/media/v1/preview_url_resource.py
@@ -56,6 +56,9 @@ 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
@@ -119,7 +122,7 @@ class PreviewUrlResource(DirectServeResource):
                 pattern = entry[attrib]
                 value = getattr(url_tuple, attrib)
                 logger.debug(
-                    "Matching attrib '%s' with value '%s' against" " pattern '%s'",
+                    "Matching attrib '%s' with value '%s' against pattern '%s'",
                     attrib,
                     value,
                     pattern,
@@ -171,7 +174,7 @@ 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)
@@ -272,6 +275,18 @@ class PreviewUrlResource(DirectServeResource):
             logger.warning("Failed to find any OG data in %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)
@@ -506,6 +521,10 @@ def _calc_og(tree, media_uri):
     og = {}
     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.: