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-rw-r--r--.travis.yml10
-rw-r--r--CHANGES.rst69
-rw-r--r--CONTRIBUTING.rst34
-rw-r--r--MANIFEST.in3
-rw-r--r--changelog.d/.gitignore1
-rw-r--r--changelog.d/3463.misc0
-rw-r--r--docs/admin_api/user_admin_api.rst17
-rw-r--r--pyproject.toml5
-rw-r--r--setup.cfg12
-rw-r--r--synapse/__init__.py2
-rw-r--r--synapse/api/auth.py10
-rw-r--r--synapse/api/constants.py2
-rw-r--r--synapse/api/errors.py3
-rw-r--r--synapse/api/filtering.py3
-rw-r--r--synapse/appservice/__init__.py4
-rw-r--r--synapse/config/appservice.py12
-rw-r--r--synapse/config/server.py11
-rw-r--r--synapse/crypto/keyclient.py2
-rw-r--r--synapse/event_auth.py7
-rw-r--r--synapse/federation/federation_server.py156
-rw-r--r--synapse/federation/transport/server.py75
-rw-r--r--synapse/handlers/auth.py5
-rw-r--r--synapse/handlers/deactivate_account.py12
-rw-r--r--synapse/handlers/e2e_keys.py7
-rw-r--r--synapse/handlers/federation.py150
-rw-r--r--synapse/handlers/identity.py2
-rw-r--r--synapse/handlers/message.py17
-rw-r--r--synapse/handlers/presence.py4
-rw-r--r--synapse/handlers/sync.py2
-rw-r--r--synapse/http/client.py2
-rw-r--r--synapse/http/endpoint.py89
-rw-r--r--synapse/http/matrixfederationclient.py3
-rw-r--r--synapse/http/server.py5
-rw-r--r--synapse/http/servlet.py6
-rw-r--r--synapse/http/site.py19
-rw-r--r--synapse/metrics/__init__.py3
-rw-r--r--synapse/push/emailpusher.py4
-rw-r--r--synapse/push/httppusher.py6
-rw-r--r--synapse/python_dependencies.py6
-rw-r--r--synapse/replication/slave/storage/events.py2
-rw-r--r--synapse/replication/tcp/client.py6
-rw-r--r--synapse/replication/tcp/commands.py16
-rw-r--r--synapse/replication/tcp/resource.py4
-rw-r--r--synapse/rest/client/v1/admin.py15
-rw-r--r--synapse/rest/client/v1/login.py3
-rw-r--r--synapse/rest/client/v1/room.py2
-rw-r--r--synapse/rest/client/v2_alpha/account.py13
-rw-r--r--synapse/rest/client/v2_alpha/sync.py2
-rw-r--r--synapse/rest/media/v0/content_repository.py3
-rw-r--r--synapse/rest/media/v1/preview_url_resource.py3
-rw-r--r--synapse/storage/__init__.py2
-rw-r--r--synapse/storage/account_data.py3
-rw-r--r--synapse/storage/appservice.py2
-rw-r--r--synapse/storage/background_updates.py3
-rw-r--r--synapse/storage/deviceinbox.py13
-rw-r--r--synapse/storage/devices.py3
-rw-r--r--synapse/storage/end_to_end_keys.py3
-rw-r--r--synapse/storage/event_push_actions.py3
-rw-r--r--synapse/storage/events.py6
-rw-r--r--synapse/storage/events_worker.py3
-rw-r--r--synapse/storage/filtering.py3
-rw-r--r--synapse/storage/group_server.py2
-rw-r--r--synapse/storage/push_rule.py3
-rw-r--r--synapse/storage/pusher.py3
-rw-r--r--synapse/storage/receipts.py3
-rw-r--r--synapse/storage/registration.py4
-rw-r--r--synapse/storage/room.py3
-rw-r--r--synapse/storage/roommember.py2
-rw-r--r--synapse/storage/schema/delta/50/erasure_store.sql21
-rw-r--r--synapse/storage/search.py2
-rw-r--r--synapse/storage/tags.py3
-rw-r--r--synapse/storage/transactions.py3
-rw-r--r--synapse/storage/user_erasure_store.py103
-rw-r--r--synapse/util/__init__.py3
-rw-r--r--synapse/util/caches/stream_change_cache.py6
-rw-r--r--synapse/util/frozenutils.py2
-rw-r--r--synapse/visibility.py77
-rw-r--r--tests/api/test_auth.py51
-rw-r--r--tests/federation/__init__.py0
-rw-r--r--tests/federation/test_federation_server.py57
-rw-r--r--tests/http/__init__.py0
-rw-r--r--tests/http/test_endpoint.py55
-rw-r--r--tests/server.py181
-rw-r--r--tests/test_federation.py243
-rw-r--r--tests/test_server.py128
-rw-r--r--tests/unittest.py5
-rw-r--r--tests/util/caches/test_descriptors.py17
-rw-r--r--tox.ini8
88 files changed, 1673 insertions, 205 deletions
diff --git a/.travis.yml b/.travis.yml
index e6ba6f4752..a98d547978 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -4,7 +4,12 @@ language: python
 # tell travis to cache ~/.cache/pip
 cache: pip
 
+before_script:
+  - git remote set-branches --add origin develop
+  - git fetch origin develop
+
 matrix:
+  fast_finish: true
   include:
   - python: 2.7
     env: TOX_ENV=packaging
@@ -14,10 +19,13 @@ matrix:
 
   - python: 2.7
     env: TOX_ENV=py27
-    
+
   - python: 3.6
     env: TOX_ENV=py36
 
+  - python: 3.6
+    env: TOX_ENV=check-newsfragment
+
 install:
   - pip install tox
 
diff --git a/CHANGES.rst b/CHANGES.rst
index 70fc5af4c1..ba6929c435 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -1,3 +1,72 @@
+Synapse 0.32.2 (2018-07-07)
+===========================
+
+Bugfixes
+--------
+
+- Amend the Python dependencies to depend on attrs from PyPI, not attr (`#3492 <https://github.com/matrix-org/synapse/issues/3492>`_)
+
+
+Synapse 0.32.1 (2018-07-06)
+===========================
+
+Bugfixes
+--------
+
+- Add explicit dependency on netaddr (`#3488 <https://github.com/matrix-org/synapse/issues/3488>`_)
+
+
+Changes in synapse v0.32.0 (2018-07-06)
+===========================================
+No changes since 0.32.0rc1
+
+Synapse 0.32.0rc1 (2018-07-05)
+==============================
+
+Features
+--------
+
+- Add blacklist & whitelist of servers allowed to send events to a room via ``m.room.server_acl`` event.
+- Cache factor override system for specific caches (`#3334 <https://github.com/matrix-org/synapse/issues/3334>`_)
+- Add metrics to track appservice transactions (`#3344 <https://github.com/matrix-org/synapse/issues/3344>`_)
+- Try to log more helpful info when a sig verification fails (`#3372 <https://github.com/matrix-org/synapse/issues/3372>`_)
+- Synapse now uses the best performing JSON encoder/decoder according to your runtime (simplejson on CPython, stdlib json on PyPy). (`#3462 <https://github.com/matrix-org/synapse/issues/3462>`_)
+- Add optional ip_range_whitelist param to AS registration files to lock AS IP access (`#3465 <https://github.com/matrix-org/synapse/issues/3465>`_)
+- Reject invalid server names in federation requests (`#3480 <https://github.com/matrix-org/synapse/issues/3480>`_)
+- Reject invalid server names in homeserver.yaml (`#3483 <https://github.com/matrix-org/synapse/issues/3483>`_)
+
+
+Bugfixes
+--------
+
+- Strip access_token from outgoing requests (`#3327 <https://github.com/matrix-org/synapse/issues/3327>`_)
+- Redact AS tokens in logs (`#3349 <https://github.com/matrix-org/synapse/issues/3349>`_)
+- Fix federation backfill from SQLite servers (`#3355 <https://github.com/matrix-org/synapse/issues/3355>`_)
+- Fix event-purge-by-ts admin API (`#3363 <https://github.com/matrix-org/synapse/issues/3363>`_)
+- Fix event filtering in get_missing_events handler (`#3371 <https://github.com/matrix-org/synapse/issues/3371>`_)
+- Synapse is now stricter regarding accepting events which it cannot retrieve the prev_events for. (`#3456 <https://github.com/matrix-org/synapse/issues/3456>`_)
+- Fix bug where synapse would explode when receiving unicode in HTTP User-Agent header (`#3470 <https://github.com/matrix-org/synapse/issues/3470>`_)
+- Invalidate cache on correct thread to avoid race (`#3473 <https://github.com/matrix-org/synapse/issues/3473>`_)
+
+
+Improved Documentation
+----------------------
+
+- ``doc/postgres.rst``: fix display of the last command block. Thanks to @ArchangeGabriel! (`#3340 <https://github.com/matrix-org/synapse/issues/3340>`_)
+
+
+Deprecations and Removals
+-------------------------
+
+- Remove was_forgotten_at (`#3324 <https://github.com/matrix-org/synapse/issues/3324>`_)
+
+
+Misc
+----
+
+- `#3332 <https://github.com/matrix-org/synapse/issues/3332>`_, `#3341 <https://github.com/matrix-org/synapse/issues/3341>`_, `#3347 <https://github.com/matrix-org/synapse/issues/3347>`_, `#3348 <https://github.com/matrix-org/synapse/issues/3348>`_, `#3356 <https://github.com/matrix-org/synapse/issues/3356>`_, `#3385 <https://github.com/matrix-org/synapse/issues/3385>`_, `#3446 <https://github.com/matrix-org/synapse/issues/3446>`_, `#3447 <https://github.com/matrix-org/synapse/issues/3447>`_, `#3467 <https://github.com/matrix-org/synapse/issues/3467>`_, `#3474 <https://github.com/matrix-org/synapse/issues/3474>`_
+
+
 Changes in synapse v0.31.2 (2018-06-14)
 =======================================
 
diff --git a/CONTRIBUTING.rst b/CONTRIBUTING.rst
index c6ee16efc7..6c295cfbfe 100644
--- a/CONTRIBUTING.rst
+++ b/CONTRIBUTING.rst
@@ -48,6 +48,26 @@ Please ensure your changes match the cosmetic style of the existing project,
 and **never** mix cosmetic and functional changes in the same commit, as it
 makes it horribly hard to review otherwise.
 
+Changelog
+~~~~~~~~~
+
+All changes, even minor ones, need a corresponding changelog
+entry. These are managed by Towncrier
+(https://github.com/hawkowl/towncrier).
+
+To create a changelog entry, make a new file in the ``changelog.d``
+file named in the format of ``issuenumberOrPR.type``. The type can be
+one of ``feature``, ``bugfix``, ``removal`` (also used for
+deprecations), or ``misc`` (for internal-only changes). The content of
+the file is your changelog entry, which can contain RestructuredText
+formatting. A note of contributors is welcomed in changelogs for
+non-misc changes (the content of misc changes is not displayed).
+
+For example, a fix for a bug reported in #1234 would have its
+changelog entry in ``changelog.d/1234.bugfix``, and contain content
+like "The security levels of Florbs are now validated when
+recieved over federation. Contributed by Jane Matrix".
+
 Attribution
 ~~~~~~~~~~~
 
@@ -110,11 +130,15 @@ If you agree to this for your contribution, then all that's needed is to
 include the line in your commit or pull request comment::
 
     Signed-off-by: Your Name <your@email.example.org>
-    
-...using your real name; unfortunately pseudonyms and anonymous contributions
-can't be accepted. Git makes this trivial - just use the -s flag when you do
-``git commit``, having first set ``user.name`` and ``user.email`` git configs
-(which you should have done anyway :)
+
+We accept contributions under a legally identifiable name, such as
+your name on government documentation or common-law names (names
+claimed by legitimate usage or repute). Unfortunately, we cannot
+accept anonymous contributions at this time.
+
+Git allows you to add this signoff automatically when using the ``-s``
+flag to ``git commit``, which uses the name and email set in your
+``user.name`` and ``user.email`` git configs.
 
 Conclusion
 ~~~~~~~~~~
diff --git a/MANIFEST.in b/MANIFEST.in
index e2a6623a63..97f57f443f 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -29,5 +29,8 @@ exclude Dockerfile
 exclude .dockerignore
 recursive-exclude jenkins *.sh
 
+include pyproject.toml
+recursive-include changelog.d *
+
 prune .github
 prune demo/etc
diff --git a/changelog.d/.gitignore b/changelog.d/.gitignore
new file mode 100644
index 0000000000..f935021a8f
--- /dev/null
+++ b/changelog.d/.gitignore
@@ -0,0 +1 @@
+!.gitignore
diff --git a/changelog.d/3463.misc b/changelog.d/3463.misc
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/changelog.d/3463.misc
diff --git a/docs/admin_api/user_admin_api.rst b/docs/admin_api/user_admin_api.rst
index 1c9c5a6bde..d17121a188 100644
--- a/docs/admin_api/user_admin_api.rst
+++ b/docs/admin_api/user_admin_api.rst
@@ -44,13 +44,26 @@ Deactivate Account
 
 This API deactivates an account. It removes active access tokens, resets the
 password, and deletes third-party IDs (to prevent the user requesting a
-password reset).
+password reset). It can also mark the user as GDPR-erased (stopping their data
+from distributed further, and deleting it entirely if there are no other
+references to it).
 
 The api is::
 
     POST /_matrix/client/r0/admin/deactivate/<user_id>
 
-including an ``access_token`` of a server admin, and an empty request body.
+with a body of:
+
+.. code:: json
+
+    {
+        "erase": true
+    }
+
+including an ``access_token`` of a server admin.
+
+The erase parameter is optional and defaults to 'false'.
+An empty body may be passed for backwards compatibility.
 
 
 Reset password
diff --git a/pyproject.toml b/pyproject.toml
new file mode 100644
index 0000000000..d1603b5d8b
--- /dev/null
+++ b/pyproject.toml
@@ -0,0 +1,5 @@
+[tool.towncrier]
+    package = "synapse"
+    filename = "CHANGES.rst"
+    directory = "changelog.d"
+    issue_format = "`#{issue} <https://github.com/matrix-org/synapse/issues/{issue}>`_"
diff --git a/setup.cfg b/setup.cfg
index fa6f2d1ce4..9b5b75cd60 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -19,3 +19,15 @@ max-line-length = 90
 #  W503 requires that binary operators be at the end, not start, of lines. Erik doesn't like it.
 #  E203 is contrary to PEP8.
 ignore = W503,E203
+
+[isort]
+line_length = 89
+not_skip = __init__.py
+sections=FUTURE,STDLIB,COMPAT,THIRDPARTY,TWISTED,FIRSTPARTY,TESTS,LOCALFOLDER
+default_section=THIRDPARTY
+known_first_party = synapse
+known_tests=tests
+known_compat = mock,six
+known_twisted=twisted,OpenSSL
+multi_line_output=3
+include_trailing_comma=true
diff --git a/synapse/__init__.py b/synapse/__init__.py
index faa183a99e..3cde33c0d7 100644
--- a/synapse/__init__.py
+++ b/synapse/__init__.py
@@ -17,4 +17,4 @@
 """ This is a reference implementation of a Matrix home server.
 """
 
-__version__ = "0.31.2"
+__version__ = "0.32.2"
diff --git a/synapse/api/auth.py b/synapse/api/auth.py
index 66639b0089..088b4e8b6d 100644
--- a/synapse/api/auth.py
+++ b/synapse/api/auth.py
@@ -19,6 +19,7 @@ from six import itervalues
 
 import pymacaroons
 from twisted.internet import defer
+from netaddr import IPAddress
 
 import synapse.types
 from synapse import event_auth
@@ -244,6 +245,11 @@ class Auth(object):
         if app_service is None:
             defer.returnValue((None, None))
 
+        if app_service.ip_range_whitelist:
+            ip_address = IPAddress(self.hs.get_ip_from_request(request))
+            if ip_address not in app_service.ip_range_whitelist:
+                defer.returnValue((None, None))
+
         if "user_id" not in request.args:
             defer.returnValue((app_service.sender, app_service))
 
@@ -488,7 +494,7 @@ class Auth(object):
     def _look_up_user_by_access_token(self, token):
         ret = yield self.store.get_user_by_access_token(token)
         if not ret:
-            logger.warn("Unrecognised access token - not in store: %s" % (token,))
+            logger.warn("Unrecognised access token - not in store.")
             raise AuthError(
                 self.TOKEN_NOT_FOUND_HTTP_STATUS, "Unrecognised access token.",
                 errcode=Codes.UNKNOWN_TOKEN
@@ -511,7 +517,7 @@ class Auth(object):
             )
             service = self.store.get_app_service_by_token(token)
             if not service:
-                logger.warn("Unrecognised appservice access token: %s" % (token,))
+                logger.warn("Unrecognised appservice access token.")
                 raise AuthError(
                     self.TOKEN_NOT_FOUND_HTTP_STATUS,
                     "Unrecognised access token.",
diff --git a/synapse/api/constants.py b/synapse/api/constants.py
index 5baba43966..4df930c8d1 100644
--- a/synapse/api/constants.py
+++ b/synapse/api/constants.py
@@ -76,6 +76,8 @@ class EventTypes(object):
     Topic = "m.room.topic"
     Name = "m.room.name"
 
+    ServerACL = "m.room.server_acl"
+
 
 class RejectedReason(object):
     AUTH_ERROR = "auth_error"
diff --git a/synapse/api/errors.py b/synapse/api/errors.py
index e6ad3768f0..227a0713b2 100644
--- a/synapse/api/errors.py
+++ b/synapse/api/errors.py
@@ -17,7 +17,8 @@
 
 import logging
 
-import simplejson as json
+from canonicaljson import json
+
 from six import iteritems
 from six.moves import http_client
 
diff --git a/synapse/api/filtering.py b/synapse/api/filtering.py
index dbc0e7e445..aae25e7a47 100644
--- a/synapse/api/filtering.py
+++ b/synapse/api/filtering.py
@@ -17,7 +17,8 @@ from synapse.storage.presence import UserPresenceState
 from synapse.types import UserID, RoomID
 from twisted.internet import defer
 
-import simplejson as json
+from canonicaljson import json
+
 import jsonschema
 from jsonschema import FormatChecker
 
diff --git a/synapse/appservice/__init__.py b/synapse/appservice/__init__.py
index d1c598622a..328cbfa284 100644
--- a/synapse/appservice/__init__.py
+++ b/synapse/appservice/__init__.py
@@ -85,7 +85,8 @@ class ApplicationService(object):
     NS_LIST = [NS_USERS, NS_ALIASES, NS_ROOMS]
 
     def __init__(self, token, hostname, url=None, namespaces=None, hs_token=None,
-                 sender=None, id=None, protocols=None, rate_limited=True):
+                 sender=None, id=None, protocols=None, rate_limited=True,
+                 ip_range_whitelist=None):
         self.token = token
         self.url = url
         self.hs_token = hs_token
@@ -93,6 +94,7 @@ class ApplicationService(object):
         self.server_name = hostname
         self.namespaces = self._check_namespaces(namespaces)
         self.id = id
+        self.ip_range_whitelist = ip_range_whitelist
 
         if "|" in self.id:
             raise Exception("application service ID cannot contain '|' character")
diff --git a/synapse/config/appservice.py b/synapse/config/appservice.py
index 277305e184..0c27bb2fa7 100644
--- a/synapse/config/appservice.py
+++ b/synapse/config/appservice.py
@@ -17,6 +17,8 @@ from ._base import Config, ConfigError
 from synapse.appservice import ApplicationService
 from synapse.types import UserID
 
+from netaddr import IPSet
+
 import yaml
 import logging
 
@@ -154,6 +156,13 @@ def _load_appservice(hostname, as_info, config_filename):
             " will not receive events or queries.",
             config_filename,
         )
+
+    ip_range_whitelist = None
+    if as_info.get('ip_range_whitelist'):
+        ip_range_whitelist = IPSet(
+            as_info.get('ip_range_whitelist')
+        )
+
     return ApplicationService(
         token=as_info["as_token"],
         hostname=hostname,
@@ -163,5 +172,6 @@ def _load_appservice(hostname, as_info, config_filename):
         sender=user_id,
         id=as_info["id"],
         protocols=protocols,
-        rate_limited=rate_limited
+        rate_limited=rate_limited,
+        ip_range_whitelist=ip_range_whitelist,
     )
diff --git a/synapse/config/server.py b/synapse/config/server.py
index 968ecd9ea0..71fd51e4bc 100644
--- a/synapse/config/server.py
+++ b/synapse/config/server.py
@@ -16,6 +16,7 @@
 
 import logging
 
+from synapse.http.endpoint import parse_and_validate_server_name
 from ._base import Config, ConfigError
 
 logger = logging.Logger(__name__)
@@ -25,6 +26,12 @@ class ServerConfig(Config):
 
     def read_config(self, config):
         self.server_name = config["server_name"]
+
+        try:
+            parse_and_validate_server_name(self.server_name)
+        except ValueError as e:
+            raise ConfigError(str(e))
+
         self.pid_file = self.abspath(config.get("pid_file"))
         self.web_client = config["web_client"]
         self.web_client_location = config.get("web_client_location", None)
@@ -162,8 +169,8 @@ class ServerConfig(Config):
             })
 
     def default_config(self, server_name, **kwargs):
-        if ":" in server_name:
-            bind_port = int(server_name.split(":")[1])
+        _, bind_port = parse_and_validate_server_name(server_name)
+        if bind_port is not None:
             unsecure_port = bind_port - 400
         else:
             bind_port = 8448
diff --git a/synapse/crypto/keyclient.py b/synapse/crypto/keyclient.py
index 8e48f8a9cf..e13cab9dbf 100644
--- a/synapse/crypto/keyclient.py
+++ b/synapse/crypto/keyclient.py
@@ -18,7 +18,7 @@ from twisted.web.http import HTTPClient
 from twisted.internet.protocol import Factory
 from twisted.internet import defer, reactor
 from synapse.http.endpoint import matrix_federation_endpoint
-import simplejson as json
+from canonicaljson import json
 import logging
 
 
diff --git a/synapse/event_auth.py b/synapse/event_auth.py
index f512d88145..cdf99fd140 100644
--- a/synapse/event_auth.py
+++ b/synapse/event_auth.py
@@ -76,6 +76,7 @@ def check(event, auth_events, do_sig_check=True, do_size_check=True):
         return
 
     if event.type == EventTypes.Create:
+        sender_domain = get_domain_from_id(event.sender)
         room_id_domain = get_domain_from_id(event.room_id)
         if room_id_domain != sender_domain:
             raise AuthError(
@@ -524,7 +525,11 @@ def _check_power_levels(event, auth_events):
                     "to your own"
                 )
 
-        if old_level > user_level or new_level > user_level:
+        # Check if the old and new levels are greater than the user level
+        # (if defined)
+        old_level_too_big = old_level is not None and old_level > user_level
+        new_level_too_big = new_level is not None and new_level > user_level
+        if old_level_too_big or new_level_too_big:
             raise AuthError(
                 403,
                 "You don't have permission to add ops level greater "
diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py
index d4dd967c60..591d0026bf 100644
--- a/synapse/federation/federation_server.py
+++ b/synapse/federation/federation_server.py
@@ -14,10 +14,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import logging
+import re
 
-import simplejson as json
+from canonicaljson import json
+import six
 from twisted.internet import defer
+from twisted.internet.abstract import isIPAddress
 
+from synapse.api.constants import EventTypes
 from synapse.api.errors import AuthError, FederationError, SynapseError, NotFoundError
 from synapse.crypto.event_signing import compute_event_signature
 from synapse.federation.federation_base import (
@@ -27,6 +31,7 @@ from synapse.federation.federation_base import (
 
 from synapse.federation.persistence import TransactionActions
 from synapse.federation.units import Edu, Transaction
+from synapse.http.endpoint import parse_server_name
 from synapse.types import get_domain_from_id
 from synapse.util import async
 from synapse.util.caches.response_cache import ResponseCache
@@ -74,6 +79,9 @@ class FederationServer(FederationBase):
     @log_function
     def on_backfill_request(self, origin, room_id, versions, limit):
         with (yield self._server_linearizer.queue((origin, room_id))):
+            origin_host, _ = parse_server_name(origin)
+            yield self.check_server_matches_acl(origin_host, room_id)
+
             pdus = yield self.handler.on_backfill_request(
                 origin, room_id, versions, limit
             )
@@ -134,6 +142,8 @@ class FederationServer(FederationBase):
 
         received_pdus_counter.inc(len(transaction.pdus))
 
+        origin_host, _ = parse_server_name(transaction.origin)
+
         pdus_by_room = {}
 
         for p in transaction.pdus:
@@ -154,9 +164,21 @@ class FederationServer(FederationBase):
         # we can process different rooms in parallel (which is useful if they
         # require callouts to other servers to fetch missing events), but
         # impose a limit to avoid going too crazy with ram/cpu.
+
         @defer.inlineCallbacks
         def process_pdus_for_room(room_id):
             logger.debug("Processing PDUs for %s", room_id)
+            try:
+                yield self.check_server_matches_acl(origin_host, room_id)
+            except AuthError as e:
+                logger.warn(
+                    "Ignoring PDUs for room %s from banned server", room_id,
+                )
+                for pdu in pdus_by_room[room_id]:
+                    event_id = pdu.event_id
+                    pdu_results[event_id] = e.error_dict()
+                return
+
             for pdu in pdus_by_room[room_id]:
                 event_id = pdu.event_id
                 try:
@@ -211,6 +233,9 @@ class FederationServer(FederationBase):
         if not event_id:
             raise NotImplementedError("Specify an event")
 
+        origin_host, _ = parse_server_name(origin)
+        yield self.check_server_matches_acl(origin_host, room_id)
+
         in_room = yield self.auth.check_host_in_room(room_id, origin)
         if not in_room:
             raise AuthError(403, "Host not in room.")
@@ -234,6 +259,9 @@ class FederationServer(FederationBase):
         if not event_id:
             raise NotImplementedError("Specify an event")
 
+        origin_host, _ = parse_server_name(origin)
+        yield self.check_server_matches_acl(origin_host, room_id)
+
         in_room = yield self.auth.check_host_in_room(room_id, origin)
         if not in_room:
             raise AuthError(403, "Host not in room.")
@@ -298,7 +326,9 @@ class FederationServer(FederationBase):
         defer.returnValue((200, resp))
 
     @defer.inlineCallbacks
-    def on_make_join_request(self, room_id, user_id):
+    def on_make_join_request(self, origin, room_id, user_id):
+        origin_host, _ = parse_server_name(origin)
+        yield self.check_server_matches_acl(origin_host, room_id)
         pdu = yield self.handler.on_make_join_request(room_id, user_id)
         time_now = self._clock.time_msec()
         defer.returnValue({"event": pdu.get_pdu_json(time_now)})
@@ -306,6 +336,8 @@ class FederationServer(FederationBase):
     @defer.inlineCallbacks
     def on_invite_request(self, origin, content):
         pdu = event_from_pdu_json(content)
+        origin_host, _ = parse_server_name(origin)
+        yield self.check_server_matches_acl(origin_host, pdu.room_id)
         ret_pdu = yield self.handler.on_invite_request(origin, pdu)
         time_now = self._clock.time_msec()
         defer.returnValue((200, {"event": ret_pdu.get_pdu_json(time_now)}))
@@ -314,6 +346,10 @@ class FederationServer(FederationBase):
     def on_send_join_request(self, origin, content):
         logger.debug("on_send_join_request: content: %s", content)
         pdu = event_from_pdu_json(content)
+
+        origin_host, _ = parse_server_name(origin)
+        yield self.check_server_matches_acl(origin_host, pdu.room_id)
+
         logger.debug("on_send_join_request: pdu sigs: %s", pdu.signatures)
         res_pdus = yield self.handler.on_send_join_request(origin, pdu)
         time_now = self._clock.time_msec()
@@ -325,7 +361,9 @@ class FederationServer(FederationBase):
         }))
 
     @defer.inlineCallbacks
-    def on_make_leave_request(self, room_id, user_id):
+    def on_make_leave_request(self, origin, room_id, user_id):
+        origin_host, _ = parse_server_name(origin)
+        yield self.check_server_matches_acl(origin_host, room_id)
         pdu = yield self.handler.on_make_leave_request(room_id, user_id)
         time_now = self._clock.time_msec()
         defer.returnValue({"event": pdu.get_pdu_json(time_now)})
@@ -334,6 +372,10 @@ class FederationServer(FederationBase):
     def on_send_leave_request(self, origin, content):
         logger.debug("on_send_leave_request: content: %s", content)
         pdu = event_from_pdu_json(content)
+
+        origin_host, _ = parse_server_name(origin)
+        yield self.check_server_matches_acl(origin_host, pdu.room_id)
+
         logger.debug("on_send_leave_request: pdu sigs: %s", pdu.signatures)
         yield self.handler.on_send_leave_request(origin, pdu)
         defer.returnValue((200, {}))
@@ -341,6 +383,9 @@ class FederationServer(FederationBase):
     @defer.inlineCallbacks
     def on_event_auth(self, origin, room_id, event_id):
         with (yield self._server_linearizer.queue((origin, room_id))):
+            origin_host, _ = parse_server_name(origin)
+            yield self.check_server_matches_acl(origin_host, room_id)
+
             time_now = self._clock.time_msec()
             auth_pdus = yield self.handler.on_event_auth(event_id)
             res = {
@@ -369,6 +414,9 @@ class FederationServer(FederationBase):
             Deferred: Results in `dict` with the same format as `content`
         """
         with (yield self._server_linearizer.queue((origin, room_id))):
+            origin_host, _ = parse_server_name(origin)
+            yield self.check_server_matches_acl(origin_host, room_id)
+
             auth_chain = [
                 event_from_pdu_json(e)
                 for e in content["auth_chain"]
@@ -442,6 +490,9 @@ class FederationServer(FederationBase):
     def on_get_missing_events(self, origin, room_id, earliest_events,
                               latest_events, limit, min_depth):
         with (yield self._server_linearizer.queue((origin, room_id))):
+            origin_host, _ = parse_server_name(origin)
+            yield self.check_server_matches_acl(origin_host, room_id)
+
             logger.info(
                 "on_get_missing_events: earliest_events: %r, latest_events: %r,"
                 " limit: %d, min_depth: %d",
@@ -549,7 +600,9 @@ class FederationServer(FederationBase):
                 affected=pdu.event_id,
             )
 
-        yield self.handler.on_receive_pdu(origin, pdu, get_missing=True)
+        yield self.handler.on_receive_pdu(
+            origin, pdu, get_missing=True, sent_to_us_directly=True,
+        )
 
     def __str__(self):
         return "<ReplicationLayer(%s)>" % self.server_name
@@ -577,6 +630,101 @@ class FederationServer(FederationBase):
         )
         defer.returnValue(ret)
 
+    @defer.inlineCallbacks
+    def check_server_matches_acl(self, server_name, room_id):
+        """Check if the given server is allowed by the server ACLs in the room
+
+        Args:
+            server_name (str): name of server, *without any port part*
+            room_id (str): ID of the room to check
+
+        Raises:
+            AuthError if the server does not match the ACL
+        """
+        state_ids = yield self.store.get_current_state_ids(room_id)
+        acl_event_id = state_ids.get((EventTypes.ServerACL, ""))
+
+        if not acl_event_id:
+            return
+
+        acl_event = yield self.store.get_event(acl_event_id)
+        if server_matches_acl_event(server_name, acl_event):
+            return
+
+        raise AuthError(code=403, msg="Server is banned from room")
+
+
+def server_matches_acl_event(server_name, acl_event):
+    """Check if the given server is allowed by the ACL event
+
+    Args:
+        server_name (str): name of server, without any port part
+        acl_event (EventBase): m.room.server_acl event
+
+    Returns:
+        bool: True if this server is allowed by the ACLs
+    """
+    logger.debug("Checking %s against acl %s", server_name, acl_event.content)
+
+    # first of all, check if literal IPs are blocked, and if so, whether the
+    # server name is a literal IP
+    allow_ip_literals = acl_event.content.get("allow_ip_literals", True)
+    if not isinstance(allow_ip_literals, bool):
+        logger.warn("Ignorning non-bool allow_ip_literals flag")
+        allow_ip_literals = True
+    if not allow_ip_literals:
+        # check for ipv6 literals. These start with '['.
+        if server_name[0] == '[':
+            return False
+
+        # check for ipv4 literals. We can just lift the routine from twisted.
+        if isIPAddress(server_name):
+            return False
+
+    # next,  check the deny list
+    deny = acl_event.content.get("deny", [])
+    if not isinstance(deny, (list, tuple)):
+        logger.warn("Ignorning non-list deny ACL %s", deny)
+        deny = []
+    for e in deny:
+        if _acl_entry_matches(server_name, e):
+            # logger.info("%s matched deny rule %s", server_name, e)
+            return False
+
+    # then the allow list.
+    allow = acl_event.content.get("allow", [])
+    if not isinstance(allow, (list, tuple)):
+        logger.warn("Ignorning non-list allow ACL %s", allow)
+        allow = []
+    for e in allow:
+        if _acl_entry_matches(server_name, e):
+            # logger.info("%s matched allow rule %s", server_name, e)
+            return True
+
+    # everything else should be rejected.
+    # logger.info("%s fell through", server_name)
+    return False
+
+
+def _acl_entry_matches(server_name, acl_entry):
+    if not isinstance(acl_entry, six.string_types):
+        logger.warn("Ignoring non-str ACL entry '%s' (is %s)", acl_entry, type(acl_entry))
+        return False
+    regex = _glob_to_regex(acl_entry)
+    return regex.match(server_name)
+
+
+def _glob_to_regex(glob):
+    res = ''
+    for c in glob:
+        if c == '*':
+            res = res + '.*'
+        elif c == '?':
+            res = res + '.'
+        else:
+            res = res + re.escape(c)
+    return re.compile(res + "\\Z", re.IGNORECASE)
+
 
 class FederationHandlerRegistry(object):
     """Allows classes to register themselves as handlers for a given EDU or
diff --git a/synapse/federation/transport/server.py b/synapse/federation/transport/server.py
index 19d09f5422..c6d98d35cb 100644
--- a/synapse/federation/transport/server.py
+++ b/synapse/federation/transport/server.py
@@ -18,6 +18,7 @@ from twisted.internet import defer
 
 from synapse.api.urls import FEDERATION_PREFIX as PREFIX
 from synapse.api.errors import Codes, SynapseError, FederationDeniedError
+from synapse.http.endpoint import parse_and_validate_server_name
 from synapse.http.server import JsonResource
 from synapse.http.servlet import (
     parse_json_object_from_request, parse_integer_from_args, parse_string_from_args,
@@ -99,26 +100,6 @@ class Authenticator(object):
 
         origin = None
 
-        def parse_auth_header(header_str):
-            try:
-                params = auth.split(" ")[1].split(",")
-                param_dict = dict(kv.split("=") for kv in params)
-
-                def strip_quotes(value):
-                    if value.startswith("\""):
-                        return value[1:-1]
-                    else:
-                        return value
-
-                origin = strip_quotes(param_dict["origin"])
-                key = strip_quotes(param_dict["key"])
-                sig = strip_quotes(param_dict["sig"])
-                return (origin, key, sig)
-            except Exception:
-                raise AuthenticationError(
-                    400, "Malformed Authorization header", Codes.UNAUTHORIZED
-                )
-
         auth_headers = request.requestHeaders.getRawHeaders(b"Authorization")
 
         if not auth_headers:
@@ -127,8 +108,8 @@ class Authenticator(object):
             )
 
         for auth in auth_headers:
-            if auth.startswith("X-Matrix"):
-                (origin, key, sig) = parse_auth_header(auth)
+            if auth.startswith(b"X-Matrix"):
+                (origin, key, sig) = _parse_auth_header(auth)
                 json_request["origin"] = origin
                 json_request["signatures"].setdefault(origin, {})[key] = sig
 
@@ -165,6 +146,48 @@ class Authenticator(object):
             logger.exception("Error resetting retry timings on %s", origin)
 
 
+def _parse_auth_header(header_bytes):
+    """Parse an X-Matrix auth header
+
+    Args:
+        header_bytes (bytes): header value
+
+    Returns:
+        Tuple[str, str, str]: origin, key id, signature.
+
+    Raises:
+        AuthenticationError if the header could not be parsed
+    """
+    try:
+        header_str = header_bytes.decode('utf-8')
+        params = header_str.split(" ")[1].split(",")
+        param_dict = dict(kv.split("=") for kv in params)
+
+        def strip_quotes(value):
+            if value.startswith(b"\""):
+                return value[1:-1]
+            else:
+                return value
+
+        origin = strip_quotes(param_dict["origin"])
+
+        # ensure that the origin is a valid server name
+        parse_and_validate_server_name(origin)
+
+        key = strip_quotes(param_dict["key"])
+        sig = strip_quotes(param_dict["sig"])
+        return origin, key, sig
+    except Exception as e:
+        logger.warn(
+            "Error parsing auth header '%s': %s",
+            header_bytes.decode('ascii', 'replace'),
+            e,
+        )
+        raise AuthenticationError(
+            400, "Malformed Authorization header", Codes.UNAUTHORIZED,
+        )
+
+
 class BaseFederationServlet(object):
     REQUIRE_AUTH = True
 
@@ -362,7 +385,9 @@ class FederationMakeJoinServlet(BaseFederationServlet):
 
     @defer.inlineCallbacks
     def on_GET(self, origin, content, query, context, user_id):
-        content = yield self.handler.on_make_join_request(context, user_id)
+        content = yield self.handler.on_make_join_request(
+            origin, context, user_id,
+        )
         defer.returnValue((200, content))
 
 
@@ -371,7 +396,9 @@ class FederationMakeLeaveServlet(BaseFederationServlet):
 
     @defer.inlineCallbacks
     def on_GET(self, origin, content, query, context, user_id):
-        content = yield self.handler.on_make_leave_request(context, user_id)
+        content = yield self.handler.on_make_leave_request(
+            origin, context, user_id,
+        )
         defer.returnValue((200, content))
 
 
diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py
index a131b7f73f..cbef1f2770 100644
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -16,6 +16,8 @@
 
 from twisted.internet import defer, threads
 
+from canonicaljson import json
+
 from ._base import BaseHandler
 from synapse.api.constants import LoginType
 from synapse.api.errors import (
@@ -32,7 +34,6 @@ from twisted.web.client import PartialDownloadError
 import logging
 import bcrypt
 import pymacaroons
-import simplejson
 import attr
 
 import synapse.util.stringutils as stringutils
@@ -403,7 +404,7 @@ class AuthHandler(BaseHandler):
         except PartialDownloadError as pde:
             # Twisted is silly
             data = pde.response
-            resp_body = simplejson.loads(data)
+            resp_body = json.loads(data)
 
         if 'success' in resp_body:
             # Note that we do NOT check the hostname here: we explicitly
diff --git a/synapse/handlers/deactivate_account.py b/synapse/handlers/deactivate_account.py
index 8ec5ba2012..a84b7b8b80 100644
--- a/synapse/handlers/deactivate_account.py
+++ b/synapse/handlers/deactivate_account.py
@@ -12,7 +12,7 @@
 # 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.internet import defer, reactor
+from twisted.internet import defer
 
 from ._base import BaseHandler
 from synapse.types import UserID, create_requester
@@ -39,14 +39,15 @@ class DeactivateAccountHandler(BaseHandler):
 
         # Start the user parter loop so it can resume parting users from rooms where
         # it left off (if it has work left to do).
-        reactor.callWhenRunning(self._start_user_parting)
+        hs.get_reactor().callWhenRunning(self._start_user_parting)
 
     @defer.inlineCallbacks
-    def deactivate_account(self, user_id):
+    def deactivate_account(self, user_id, erase_data):
         """Deactivate a user's account
 
         Args:
             user_id (str): ID of user to be deactivated
+            erase_data (bool): whether to GDPR-erase the user's data
 
         Returns:
             Deferred
@@ -92,6 +93,11 @@ class DeactivateAccountHandler(BaseHandler):
         # delete from user directory
         yield self.user_directory_handler.handle_user_deactivated(user_id)
 
+        # Mark the user as erased, if they asked for that
+        if erase_data:
+            logger.info("Marking %s as erased", user_id)
+            yield self.store.mark_user_erased(user_id)
+
         # Now start the process that goes through that list and
         # parts users from rooms (if it isn't already running)
         self._start_user_parting()
diff --git a/synapse/handlers/e2e_keys.py b/synapse/handlers/e2e_keys.py
index 8a2d177539..62b4892a4e 100644
--- a/synapse/handlers/e2e_keys.py
+++ b/synapse/handlers/e2e_keys.py
@@ -14,10 +14,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import simplejson as json
 import logging
 
-from canonicaljson import encode_canonical_json
+from canonicaljson import encode_canonical_json, json
 from twisted.internet import defer
 from six import iteritems
 
@@ -80,7 +79,7 @@ class E2eKeysHandler(object):
             else:
                 remote_queries[user_id] = device_ids
 
-        # Firt get local devices.
+        # First get local devices.
         failures = {}
         results = {}
         if local_query:
@@ -357,7 +356,7 @@ def _exception_to_failure(e):
     # include ConnectionRefused and other errors
     #
     # Note that some Exceptions (notably twisted's ResponseFailed etc) don't
-    # give a string for e.message, which simplejson then fails to serialize.
+    # give a string for e.message, which json then fails to serialize.
     return {
         "status": 503, "message": str(e.message),
     }
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 2571758284..13117d70fe 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -44,6 +44,7 @@ from synapse.util.frozenutils import unfreeze
 from synapse.crypto.event_signing import (
     compute_event_signature, add_hashes_and_signatures,
 )
+from synapse.state import resolve_events_with_factory
 from synapse.types import UserID, get_domain_from_id
 
 from synapse.events.utils import prune_event
@@ -89,7 +90,9 @@ class FederationHandler(BaseHandler):
 
     @defer.inlineCallbacks
     @log_function
-    def on_receive_pdu(self, origin, pdu, get_missing=True):
+    def on_receive_pdu(
+            self, origin, pdu, get_missing=True, sent_to_us_directly=False,
+    ):
         """ Process a PDU received via a federation /send/ transaction, or
         via backfill of missing prev_events
 
@@ -163,14 +166,11 @@ class FederationHandler(BaseHandler):
                     "Ignoring PDU %s for room %s from %s as we've left the room!",
                     pdu.event_id, pdu.room_id, origin,
                 )
-                return
+                defer.returnValue(None)
 
         state = None
-
         auth_chain = []
 
-        fetch_state = False
-
         # Get missing pdus if necessary.
         if not pdu.internal_metadata.is_outlier():
             # We only backfill backwards to the min depth.
@@ -225,26 +225,60 @@ class FederationHandler(BaseHandler):
                         list(prevs - seen)[:5],
                     )
 
-            if prevs - seen:
-                logger.info(
-                    "Still missing %d events for room %r: %r...",
-                    len(prevs - seen), pdu.room_id, list(prevs - seen)[:5]
+            if sent_to_us_directly and prevs - seen:
+                # If they have sent it to us directly, and the server
+                # isn't telling us about the auth events that it's
+                # made a message referencing, we explode
+                raise FederationError(
+                    "ERROR",
+                    403,
+                    (
+                        "Your server isn't divulging details about prev_events "
+                        "referenced in this event."
+                    ),
+                    affected=pdu.event_id,
                 )
-                fetch_state = True
+            elif prevs - seen:
+                # Calculate the state of the previous events, and
+                # de-conflict them to find the current state.
+                state_groups = []
+                auth_chains = set()
+                try:
+                    # Get the state of the events we know about
+                    ours = yield self.store.get_state_groups(pdu.room_id, list(seen))
+                    state_groups.append(ours)
+
+                    # Ask the remote server for the states we don't
+                    # know about
+                    for p in prevs - seen:
+                        state, got_auth_chain = (
+                            yield self.replication_layer.get_state_for_room(
+                                origin, pdu.room_id, p
+                            )
+                        )
+                        auth_chains.update(got_auth_chain)
+                        state_group = {(x.type, x.state_key): x.event_id for x in state}
+                        state_groups.append(state_group)
+
+                    # Resolve any conflicting state
+                    def fetch(ev_ids):
+                        return self.store.get_events(
+                            ev_ids, get_prev_content=False, check_redacted=False
+                        )
 
-        if fetch_state:
-            # We need to get the state at this event, since we haven't
-            # processed all the prev events.
-            logger.debug(
-                "_handle_new_pdu getting state for %s",
-                pdu.room_id
-            )
-            try:
-                state, auth_chain = yield self.replication_layer.get_state_for_room(
-                    origin, pdu.room_id, pdu.event_id,
-                )
-            except Exception:
-                logger.exception("Failed to get state for event: %s", pdu.event_id)
+                    state_map = yield resolve_events_with_factory(
+                        state_groups, {pdu.event_id: pdu}, fetch
+                    )
+
+                    state = (yield self.store.get_events(state_map.values())).values()
+                    auth_chain = list(auth_chains)
+                except Exception:
+                    raise FederationError(
+                        "ERROR",
+                        403,
+                        "We can't get valid state history.",
+                        affected=pdu.event_id,
+                    )
 
         yield self._process_received_pdu(
             origin,
@@ -322,11 +356,17 @@ class FederationHandler(BaseHandler):
 
         for e in missing_events:
             logger.info("Handling found event %s", e.event_id)
-            yield self.on_receive_pdu(
-                origin,
-                e,
-                get_missing=False
-            )
+            try:
+                yield self.on_receive_pdu(
+                    origin,
+                    e,
+                    get_missing=False
+                )
+            except FederationError as e:
+                if e.code == 403:
+                    logger.warn("Event %s failed history check.")
+                else:
+                    raise
 
     @log_function
     @defer.inlineCallbacks
@@ -460,6 +500,47 @@ class FederationHandler(BaseHandler):
     @measure_func("_filter_events_for_server")
     @defer.inlineCallbacks
     def _filter_events_for_server(self, server_name, room_id, events):
+        """Filter the given events for the given server, redacting those the
+        server can't see.
+
+        Assumes the server is currently in the room.
+
+        Returns
+            list[FrozenEvent]
+        """
+        # First lets check to see if all the events have a history visibility
+        # of "shared" or "world_readable". If thats the case then we don't
+        # need to check membership (as we know the server is in the room).
+        event_to_state_ids = yield self.store.get_state_ids_for_events(
+            frozenset(e.event_id for e in events),
+            types=(
+                (EventTypes.RoomHistoryVisibility, ""),
+            )
+        )
+
+        visibility_ids = set()
+        for sids in event_to_state_ids.itervalues():
+            hist = sids.get((EventTypes.RoomHistoryVisibility, ""))
+            if hist:
+                visibility_ids.add(hist)
+
+        # If we failed to find any history visibility events then the default
+        # is "shared" visiblity.
+        if not visibility_ids:
+            defer.returnValue(events)
+
+        event_map = yield self.store.get_events(visibility_ids)
+        all_open = all(
+            e.content.get("history_visibility") in (None, "shared", "world_readable")
+            for e in event_map.itervalues()
+        )
+
+        if all_open:
+            defer.returnValue(events)
+
+        # Ok, so we're dealing with events that have non-trivial visibility
+        # rules, so we need to also get the memberships of the room.
+
         event_to_state_ids = yield self.store.get_state_ids_for_events(
             frozenset(e.event_id for e in events),
             types=(
@@ -495,7 +576,20 @@ class FederationHandler(BaseHandler):
             for e_id, key_to_eid in event_to_state_ids.iteritems()
         }
 
+        erased_senders = yield self.store.are_users_erased(
+            e.sender for e in events,
+        )
+
         def redact_disallowed(event, state):
+            # if the sender has been gdpr17ed, always return a redacted
+            # copy of the event.
+            if erased_senders[event.sender]:
+                logger.info(
+                    "Sender of %s has been erased, redacting",
+                    event.event_id,
+                )
+                return prune_event(event)
+
             if not state:
                 return event
 
diff --git a/synapse/handlers/identity.py b/synapse/handlers/identity.py
index f00dfe1d3e..277c2b7760 100644
--- a/synapse/handlers/identity.py
+++ b/synapse/handlers/identity.py
@@ -19,7 +19,7 @@
 
 import logging
 
-import simplejson as json
+from canonicaljson import json
 
 from twisted.internet import defer
 
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 7b9946ab91..cbadf3c88e 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -14,13 +14,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import logging
-import simplejson
 import sys
 
-from canonicaljson import encode_canonical_json
+from canonicaljson import encode_canonical_json, json
 import six
 from six import string_types, itervalues, iteritems
-from twisted.internet import defer, reactor
+from twisted.internet import defer
 from twisted.internet.defer import succeed
 from twisted.python.failure import Failure
 
@@ -157,7 +156,7 @@ class MessageHandler(BaseHandler):
             # remove the purge from the list 24 hours after it completes
             def clear_purge():
                 del self._purges_by_id[purge_id]
-            reactor.callLater(24 * 3600, clear_purge)
+            self.hs.get_reactor().callLater(24 * 3600, clear_purge)
 
     def get_purge_status(self, purge_id):
         """Get the current status of an active purge
@@ -491,7 +490,7 @@ class EventCreationHandler(object):
                         target, e
                     )
 
-        is_exempt = yield self._is_exempt_from_privacy_policy(builder)
+        is_exempt = yield self._is_exempt_from_privacy_policy(builder, requester)
         if not is_exempt:
             yield self.assert_accepted_privacy_policy(requester)
 
@@ -509,12 +508,13 @@ class EventCreationHandler(object):
 
         defer.returnValue((event, context))
 
-    def _is_exempt_from_privacy_policy(self, builder):
+    def _is_exempt_from_privacy_policy(self, builder, requester):
         """"Determine if an event to be sent is exempt from having to consent
         to the privacy policy
 
         Args:
             builder (synapse.events.builder.EventBuilder): event being created
+            requester (Requster): user requesting this event
 
         Returns:
             Deferred[bool]: true if the event can be sent without the user
@@ -525,6 +525,9 @@ class EventCreationHandler(object):
             membership = builder.content.get("membership", None)
             if membership == Membership.JOIN:
                 return self._is_server_notices_room(builder.room_id)
+            elif membership == Membership.LEAVE:
+                # the user is always allowed to leave (but not kick people)
+                return builder.state_key == requester.user.to_string()
         return succeed(False)
 
     @defer.inlineCallbacks
@@ -793,7 +796,7 @@ class EventCreationHandler(object):
         # Ensure that we can round trip before trying to persist in db
         try:
             dump = frozendict_json_encoder.encode(event.content)
-            simplejson.loads(dump)
+            json.loads(dump)
         except Exception:
             logger.exception("Failed to encode content: %r", event.content)
             raise
diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py
index 7fe568132f..7db59fba00 100644
--- a/synapse/handlers/presence.py
+++ b/synapse/handlers/presence.py
@@ -22,7 +22,7 @@ The methods that define policy are:
     - should_notify
 """
 
-from twisted.internet import defer, reactor
+from twisted.internet import defer
 from contextlib import contextmanager
 
 from six import itervalues, iteritems
@@ -179,7 +179,7 @@ class PresenceHandler(object):
         # have not yet been persisted
         self.unpersisted_users_changes = set()
 
-        reactor.addSystemEventTrigger("before", "shutdown", self._on_shutdown)
+        hs.get_reactor().addSystemEventTrigger("before", "shutdown", self._on_shutdown)
 
         self.serial_to_user = {}
         self._next_serial = 1
diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index 51ec727df0..7f486e48e5 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -145,7 +145,7 @@ class SyncResult(collections.namedtuple("SyncResult", [
     "invited",  # InvitedSyncResult for each invited room.
     "archived",  # ArchivedSyncResult for each archived room.
     "to_device",  # List of direct messages for the device.
-    "device_lists",  # List of user_ids whose devices have chanegd
+    "device_lists",  # List of user_ids whose devices have changed
     "device_one_time_keys_count",  # Dict of algorithm to count for one time keys
                                    # for this device
     "groups",
diff --git a/synapse/http/client.py b/synapse/http/client.py
index 46ffb41de1..5bdc484c15 100644
--- a/synapse/http/client.py
+++ b/synapse/http/client.py
@@ -42,7 +42,7 @@ from twisted.web._newclient import ResponseDone
 from six import StringIO
 
 from prometheus_client import Counter
-import simplejson as json
+from canonicaljson import json
 import logging
 import urllib
 
diff --git a/synapse/http/endpoint.py b/synapse/http/endpoint.py
index 39432da452..6056df6226 100644
--- a/synapse/http/endpoint.py
+++ b/synapse/http/endpoint.py
@@ -12,8 +12,10 @@
 # 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.
+import re
+
 from twisted.internet.endpoints import HostnameEndpoint, wrapClientTLS
-from twisted.internet import defer, reactor
+from twisted.internet import defer
 from twisted.internet.error import ConnectError
 from twisted.names import client, dns
 from twisted.names.error import DNSNameError, DomainError
@@ -37,6 +39,71 @@ _Server = collections.namedtuple(
 )
 
 
+def parse_server_name(server_name):
+    """Split a server name into host/port parts.
+
+    Args:
+        server_name (str): server name to parse
+
+    Returns:
+        Tuple[str, int|None]: host/port parts.
+
+    Raises:
+        ValueError if the server name could not be parsed.
+    """
+    try:
+        if server_name[-1] == ']':
+            # ipv6 literal, hopefully
+            return server_name, None
+
+        domain_port = server_name.rsplit(":", 1)
+        domain = domain_port[0]
+        port = int(domain_port[1]) if domain_port[1:] else None
+        return domain, port
+    except Exception:
+        raise ValueError("Invalid server name '%s'" % server_name)
+
+
+VALID_HOST_REGEX = re.compile(
+    "\\A[0-9a-zA-Z.-]+\\Z",
+)
+
+
+def parse_and_validate_server_name(server_name):
+    """Split a server name into host/port parts and do some basic validation.
+
+    Args:
+        server_name (str): server name to parse
+
+    Returns:
+        Tuple[str, int|None]: host/port parts.
+
+    Raises:
+        ValueError if the server name could not be parsed.
+    """
+    host, port = parse_server_name(server_name)
+
+    # these tests don't need to be bulletproof as we'll find out soon enough
+    # if somebody is giving us invalid data. What we *do* need is to be sure
+    # that nobody is sneaking IP literals in that look like hostnames, etc.
+
+    # look for ipv6 literals
+    if host[0] == '[':
+        if host[-1] != ']':
+            raise ValueError("Mismatched [...] in server name '%s'" % (
+                server_name,
+            ))
+        return host, port
+
+    # otherwise it should only be alphanumerics.
+    if not VALID_HOST_REGEX.match(host):
+        raise ValueError("Server name '%s' contains invalid characters" % (
+            server_name,
+        ))
+
+    return host, port
+
+
 def matrix_federation_endpoint(reactor, destination, tls_client_options_factory=None,
                                timeout=None):
     """Construct an endpoint for the given matrix destination.
@@ -50,9 +117,7 @@ def matrix_federation_endpoint(reactor, destination, tls_client_options_factory=
         timeout (int): connection timeout in seconds
     """
 
-    domain_port = destination.split(":")
-    domain = domain_port[0]
-    port = int(domain_port[1]) if domain_port[1:] else None
+    domain, port = parse_server_name(destination)
 
     endpoint_kw_args = {}
 
@@ -74,21 +139,22 @@ def matrix_federation_endpoint(reactor, destination, tls_client_options_factory=
             reactor, "matrix", domain, protocol="tcp",
             default_port=default_port, endpoint=transport_endpoint,
             endpoint_kw_args=endpoint_kw_args
-        ))
+        ), reactor)
     else:
         return _WrappingEndpointFac(transport_endpoint(
             reactor, domain, port, **endpoint_kw_args
-        ))
+        ), reactor)
 
 
 class _WrappingEndpointFac(object):
-    def __init__(self, endpoint_fac):
+    def __init__(self, endpoint_fac, reactor):
         self.endpoint_fac = endpoint_fac
+        self.reactor = reactor
 
     @defer.inlineCallbacks
     def connect(self, protocolFactory):
         conn = yield self.endpoint_fac.connect(protocolFactory)
-        conn = _WrappedConnection(conn)
+        conn = _WrappedConnection(conn, self.reactor)
         defer.returnValue(conn)
 
 
@@ -98,9 +164,10 @@ class _WrappedConnection(object):
     """
     __slots__ = ["conn", "last_request"]
 
-    def __init__(self, conn):
+    def __init__(self, conn, reactor):
         object.__setattr__(self, "conn", conn)
         object.__setattr__(self, "last_request", time.time())
+        self._reactor = reactor
 
     def __getattr__(self, name):
         return getattr(self.conn, name)
@@ -131,14 +198,14 @@ class _WrappedConnection(object):
         # Time this connection out if we haven't send a request in the last
         # N minutes
         # TODO: Cancel the previous callLater?
-        reactor.callLater(3 * 60, self._time_things_out_maybe)
+        self._reactor.callLater(3 * 60, self._time_things_out_maybe)
 
         d = self.conn.request(request)
 
         def update_request_time(res):
             self.last_request = time.time()
             # TODO: Cancel the previous callLater?
-            reactor.callLater(3 * 60, self._time_things_out_maybe)
+            self._reactor.callLater(3 * 60, self._time_things_out_maybe)
             return res
 
         d.addCallback(update_request_time)
diff --git a/synapse/http/matrixfederationclient.py b/synapse/http/matrixfederationclient.py
index b48d05fcd2..6a398c9645 100644
--- a/synapse/http/matrixfederationclient.py
+++ b/synapse/http/matrixfederationclient.py
@@ -27,7 +27,7 @@ from synapse.util import logcontext
 from synapse.util.logcontext import make_deferred_yieldable
 import synapse.util.retryutils
 
-from canonicaljson import encode_canonical_json
+from canonicaljson import encode_canonical_json, json
 
 from synapse.api.errors import (
     SynapseError, Codes, HttpResponseException, FederationDeniedError,
@@ -36,7 +36,6 @@ from synapse.api.errors import (
 from signedjson.sign import sign_json
 
 import cgi
-import simplejson as json
 import logging
 import random
 import sys
diff --git a/synapse/http/server.py b/synapse/http/server.py
index bc09b8b2be..517aaf7b5a 100644
--- a/synapse/http/server.py
+++ b/synapse/http/server.py
@@ -29,7 +29,7 @@ import synapse.metrics
 import synapse.events
 
 from canonicaljson import (
-    encode_canonical_json, encode_pretty_printed_json
+    encode_canonical_json, encode_pretty_printed_json, json
 )
 
 from twisted.internet import defer
@@ -41,7 +41,6 @@ from twisted.web.util import redirectTo
 import collections
 import logging
 import urllib
-import simplejson
 
 logger = logging.getLogger(__name__)
 
@@ -410,7 +409,7 @@ def respond_with_json(request, code, json_object, send_cors=False,
         if canonical_json or synapse.events.USE_FROZEN_DICTS:
             json_bytes = encode_canonical_json(json_object)
         else:
-            json_bytes = simplejson.dumps(json_object)
+            json_bytes = json.dumps(json_object)
 
     return respond_with_json_bytes(
         request, code, json_bytes,
diff --git a/synapse/http/servlet.py b/synapse/http/servlet.py
index ef8e62901b..ef3a01ddc7 100644
--- a/synapse/http/servlet.py
+++ b/synapse/http/servlet.py
@@ -18,7 +18,9 @@
 from synapse.api.errors import SynapseError, Codes
 
 import logging
-import simplejson
+
+from canonicaljson import json
+
 
 logger = logging.getLogger(__name__)
 
@@ -171,7 +173,7 @@ def parse_json_value_from_request(request, allow_empty_body=False):
         return None
 
     try:
-        content = simplejson.loads(content_bytes)
+        content = json.loads(content_bytes)
     except Exception as e:
         logger.warn("Unable to parse JSON: %s", e)
         raise SynapseError(400, "Content not JSON.", errcode=Codes.NOT_JSON)
diff --git a/synapse/http/site.py b/synapse/http/site.py
index 74a752d6cf..fe93643b1e 100644
--- a/synapse/http/site.py
+++ b/synapse/http/site.py
@@ -107,13 +107,28 @@ class SynapseRequest(Request):
 
         end_time = time.time()
 
+        # need to decode as it could be raw utf-8 bytes
+        # from a IDN servname in an auth header
+        authenticated_entity = self.authenticated_entity
+        if authenticated_entity is not None:
+            authenticated_entity = authenticated_entity.decode("utf-8", "replace")
+
+        # ...or could be raw utf-8 bytes in the User-Agent header.
+        # N.B. if you don't do this, the logger explodes cryptically
+        # with maximum recursion trying to log errors about
+        # the charset problem.
+        # c.f. https://github.com/matrix-org/synapse/issues/3471
+        user_agent = self.get_user_agent()
+        if user_agent is not None:
+            user_agent = user_agent.decode("utf-8", "replace")
+
         self.site.access_logger.info(
             "%s - %s - {%s}"
             " Processed request: %.3fsec (%.3fsec, %.3fsec) (%.3fsec/%.3fsec/%d)"
             " %sB %s \"%s %s %s\" \"%s\" [%d dbevts]",
             self.getClientIP(),
             self.site.site_tag,
-            self.authenticated_entity,
+            authenticated_entity,
             end_time - self.start_time,
             ru_utime,
             ru_stime,
@@ -125,7 +140,7 @@ class SynapseRequest(Request):
             self.method,
             self.get_redacted_uri(),
             self.clientproto,
-            self.get_user_agent(),
+            user_agent,
             evt_db_fetch_count,
         )
 
diff --git a/synapse/metrics/__init__.py b/synapse/metrics/__init__.py
index 7d6e0232ed..2d2397caae 100644
--- a/synapse/metrics/__init__.py
+++ b/synapse/metrics/__init__.py
@@ -147,7 +147,8 @@ class GCCounts(object):
         yield cm
 
 
-REGISTRY.register(GCCounts())
+if not running_on_pypy:
+    REGISTRY.register(GCCounts())
 
 #
 # Twisted reactor metrics
diff --git a/synapse/push/emailpusher.py b/synapse/push/emailpusher.py
index ba7286cb72..52d4f087ee 100644
--- a/synapse/push/emailpusher.py
+++ b/synapse/push/emailpusher.py
@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.internet import defer, reactor
+from twisted.internet import defer
 from twisted.internet.error import AlreadyCalled, AlreadyCancelled
 
 import logging
@@ -199,7 +199,7 @@ class EmailPusher(object):
                     self.timed_call = None
 
         if soonest_due_at is not None:
-            self.timed_call = reactor.callLater(
+            self.timed_call = self.hs.get_reactor().callLater(
                 self.seconds_until(soonest_due_at), self.on_timer
             )
 
diff --git a/synapse/push/httppusher.py b/synapse/push/httppusher.py
index bf7ff74a1a..7a481b5a1e 100644
--- a/synapse/push/httppusher.py
+++ b/synapse/push/httppusher.py
@@ -15,7 +15,7 @@
 # limitations under the License.
 import logging
 
-from twisted.internet import defer, reactor
+from twisted.internet import defer
 from twisted.internet.error import AlreadyCalled, AlreadyCancelled
 
 from . import push_rule_evaluator
@@ -220,7 +220,9 @@ class HttpPusher(object):
                     )
                 else:
                     logger.info("Push failed: delaying for %ds", self.backoff_delay)
-                    self.timed_call = reactor.callLater(self.backoff_delay, self.on_timer)
+                    self.timed_call = self.hs.get_reactor().callLater(
+                        self.backoff_delay, self.on_timer
+                    )
                     self.backoff_delay = min(self.backoff_delay * 2, self.MAX_BACKOFF_SEC)
                     break
 
diff --git a/synapse/python_dependencies.py b/synapse/python_dependencies.py
index faf6dfdb8d..987eec3ef2 100644
--- a/synapse/python_dependencies.py
+++ b/synapse/python_dependencies.py
@@ -57,16 +57,14 @@ REQUIREMENTS = {
     "phonenumbers>=8.2.0": ["phonenumbers"],
     "six": ["six"],
     "prometheus_client": ["prometheus_client"],
-    "attr": ["attr"],
+    "attrs": ["attr"],
+    "netaddr>=0.7.18": ["netaddr"],
 }
 
 CONDITIONAL_REQUIREMENTS = {
     "web_client": {
         "matrix_angular_sdk>=0.6.8": ["syweb>=0.6.8"],
     },
-    "preview_url": {
-        "netaddr>=0.7.18": ["netaddr"],
-    },
     "email.enable_notifs": {
         "Jinja2>=2.8": ["Jinja2>=2.8"],
         "bleach>=1.4.2": ["bleach>=1.4.2"],
diff --git a/synapse/replication/slave/storage/events.py b/synapse/replication/slave/storage/events.py
index b1f64ef0d8..97d3196633 100644
--- a/synapse/replication/slave/storage/events.py
+++ b/synapse/replication/slave/storage/events.py
@@ -23,6 +23,7 @@ from synapse.storage.roommember import RoomMemberWorkerStore
 from synapse.storage.state import StateGroupWorkerStore
 from synapse.storage.stream import StreamWorkerStore
 from synapse.storage.signatures import SignatureWorkerStore
+from synapse.storage.user_erasure_store import UserErasureWorkerStore
 from ._base import BaseSlavedStore
 from ._slaved_id_tracker import SlavedIdTracker
 
@@ -45,6 +46,7 @@ class SlavedEventStore(EventFederationWorkerStore,
                        EventsWorkerStore,
                        StateGroupWorkerStore,
                        SignatureWorkerStore,
+                       UserErasureWorkerStore,
                        BaseSlavedStore):
 
     def __init__(self, db_conn, hs):
diff --git a/synapse/replication/tcp/client.py b/synapse/replication/tcp/client.py
index 6d2513c4e2..bb852b00af 100644
--- a/synapse/replication/tcp/client.py
+++ b/synapse/replication/tcp/client.py
@@ -15,7 +15,7 @@
 """A replication client for use by synapse workers.
 """
 
-from twisted.internet import reactor, defer
+from twisted.internet import defer
 from twisted.internet.protocol import ReconnectingClientFactory
 
 from .commands import (
@@ -44,7 +44,7 @@ class ReplicationClientFactory(ReconnectingClientFactory):
         self.server_name = hs.config.server_name
         self._clock = hs.get_clock()  # As self.clock is defined in super class
 
-        reactor.addSystemEventTrigger("before", "shutdown", self.stopTrying)
+        hs.get_reactor().addSystemEventTrigger("before", "shutdown", self.stopTrying)
 
     def startedConnecting(self, connector):
         logger.info("Connecting to replication: %r", connector.getDestination())
@@ -95,7 +95,7 @@ class ReplicationClientHandler(object):
         factory = ReplicationClientFactory(hs, client_name, self)
         host = hs.config.worker_replication_host
         port = hs.config.worker_replication_port
-        reactor.connectTCP(host, port, factory)
+        hs.get_reactor().connectTCP(host, port, factory)
 
     def on_rdata(self, stream_name, token, rows):
         """Called when we get new replication data. By default this just pokes
diff --git a/synapse/replication/tcp/commands.py b/synapse/replication/tcp/commands.py
index 12aac3cc6b..f3908df642 100644
--- a/synapse/replication/tcp/commands.py
+++ b/synapse/replication/tcp/commands.py
@@ -19,13 +19,17 @@ allowed to be sent by which side.
 """
 
 import logging
-import simplejson
+import platform
 
+if platform.python_implementation() == "PyPy":
+    import json
+    _json_encoder = json.JSONEncoder()
+else:
+    import simplejson as json
+    _json_encoder = json.JSONEncoder(namedtuple_as_object=False)
 
 logger = logging.getLogger(__name__)
 
-_json_encoder = simplejson.JSONEncoder(namedtuple_as_object=False)
-
 
 class Command(object):
     """The base command class.
@@ -102,7 +106,7 @@ class RdataCommand(Command):
         return cls(
             stream_name,
             None if token == "batch" else int(token),
-            simplejson.loads(row_json)
+            json.loads(row_json)
         )
 
     def to_line(self):
@@ -300,7 +304,7 @@ class InvalidateCacheCommand(Command):
     def from_line(cls, line):
         cache_func, keys_json = line.split(" ", 1)
 
-        return cls(cache_func, simplejson.loads(keys_json))
+        return cls(cache_func, json.loads(keys_json))
 
     def to_line(self):
         return " ".join((
@@ -329,7 +333,7 @@ class UserIpCommand(Command):
     def from_line(cls, line):
         user_id, jsn = line.split(" ", 1)
 
-        access_token, ip, user_agent, device_id, last_seen = simplejson.loads(jsn)
+        access_token, ip, user_agent, device_id, last_seen = json.loads(jsn)
 
         return cls(
             user_id, access_token, ip, user_agent, device_id, last_seen
diff --git a/synapse/replication/tcp/resource.py b/synapse/replication/tcp/resource.py
index 63bd6d2652..95ad8c1b4c 100644
--- a/synapse/replication/tcp/resource.py
+++ b/synapse/replication/tcp/resource.py
@@ -15,7 +15,7 @@
 """The server side of the replication stream.
 """
 
-from twisted.internet import defer, reactor
+from twisted.internet import defer
 from twisted.internet.protocol import Factory
 
 from .streams import STREAMS_MAP, FederationStream
@@ -109,7 +109,7 @@ class ReplicationStreamer(object):
         self.is_looping = False
         self.pending_updates = False
 
-        reactor.addSystemEventTrigger("before", "shutdown", self.on_shutdown)
+        hs.get_reactor().addSystemEventTrigger("before", "shutdown", self.on_shutdown)
 
     def on_shutdown(self):
         # close all connections on shutdown
diff --git a/synapse/rest/client/v1/admin.py b/synapse/rest/client/v1/admin.py
index b8665a45eb..8fb08dc526 100644
--- a/synapse/rest/client/v1/admin.py
+++ b/synapse/rest/client/v1/admin.py
@@ -16,6 +16,8 @@
 
 from twisted.internet import defer
 
+from six.moves import http_client
+
 from synapse.api.constants import Membership
 from synapse.api.errors import AuthError, SynapseError, Codes, NotFoundError
 from synapse.types import UserID, create_requester
@@ -247,6 +249,15 @@ class DeactivateAccountRestServlet(ClientV1RestServlet):
 
     @defer.inlineCallbacks
     def on_POST(self, request, target_user_id):
+        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)
         requester = yield self.auth.get_user_by_req(request)
         is_admin = yield self.auth.is_server_admin(requester.user)
@@ -254,7 +265,9 @@ class DeactivateAccountRestServlet(ClientV1RestServlet):
         if not is_admin:
             raise AuthError(403, "You are not a server admin")
 
-        yield self._deactivate_account_handler.deactivate_account(target_user_id)
+        yield self._deactivate_account_handler.deactivate_account(
+            target_user_id, erase,
+        )
         defer.returnValue((200, {}))
 
 
diff --git a/synapse/rest/client/v1/login.py b/synapse/rest/client/v1/login.py
index 34df5be4e9..88ca5184cd 100644
--- a/synapse/rest/client/v1/login.py
+++ b/synapse/rest/client/v1/login.py
@@ -23,7 +23,8 @@ from synapse.util.msisdn import phone_number_to_msisdn
 
 from .base import ClientV1RestServlet, client_path_patterns
 
-import simplejson as json
+from canonicaljson import json
+
 import urllib
 from six.moves.urllib import parse as urlparse
 
diff --git a/synapse/rest/client/v1/room.py b/synapse/rest/client/v1/room.py
index 0b984987ed..e6ae5db79b 100644
--- a/synapse/rest/client/v1/room.py
+++ b/synapse/rest/client/v1/room.py
@@ -31,7 +31,7 @@ from synapse.http.servlet import (
 from six.moves.urllib import parse as urlparse
 
 import logging
-import simplejson as json
+from canonicaljson import json
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/rest/client/v2_alpha/account.py b/synapse/rest/client/v2_alpha/account.py
index e1281cfbb6..80dbc3c92e 100644
--- a/synapse/rest/client/v2_alpha/account.py
+++ b/synapse/rest/client/v2_alpha/account.py
@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 # Copyright 2015, 2016 OpenMarket Ltd
 # Copyright 2017 Vector Creations Ltd
+# Copyright 2018 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.
@@ -15,6 +16,7 @@
 # limitations under the License.
 import logging
 
+from six.moves import http_client
 from twisted.internet import defer
 
 from synapse.api.auth import has_access_token
@@ -186,13 +188,20 @@ class DeactivateAccountRestServlet(RestServlet):
     @defer.inlineCallbacks
     def on_POST(self, request):
         body = parse_json_object_from_request(request)
+        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,
+            )
 
         requester = yield 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(
-                requester.user.to_string()
+                requester.user.to_string(), erase,
             )
             defer.returnValue((200, {}))
 
@@ -200,7 +209,7 @@ class DeactivateAccountRestServlet(RestServlet):
             requester, body, self.hs.get_ip_from_request(request),
         )
         yield self._deactivate_account_handler.deactivate_account(
-            requester.user.to_string(),
+            requester.user.to_string(), erase,
         )
         defer.returnValue((200, {}))
 
diff --git a/synapse/rest/client/v2_alpha/sync.py b/synapse/rest/client/v2_alpha/sync.py
index a291cffbf1..d2aa47b326 100644
--- a/synapse/rest/client/v2_alpha/sync.py
+++ b/synapse/rest/client/v2_alpha/sync.py
@@ -33,7 +33,7 @@ from ._base import set_timeline_upper_limit
 import itertools
 import logging
 
-import simplejson as json
+from canonicaljson import json
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/rest/media/v0/content_repository.py b/synapse/rest/media/v0/content_repository.py
index 956bd5da75..e44d4276d2 100644
--- a/synapse/rest/media/v0/content_repository.py
+++ b/synapse/rest/media/v0/content_repository.py
@@ -22,8 +22,9 @@ from synapse.api.errors import (
 from twisted.protocols.basic import FileSender
 from twisted.web import server, resource
 
+from canonicaljson import json
+
 import base64
-import simplejson as json
 import logging
 import os
 import re
diff --git a/synapse/rest/media/v1/preview_url_resource.py b/synapse/rest/media/v1/preview_url_resource.py
index 565cef2b8d..adca490640 100644
--- a/synapse/rest/media/v1/preview_url_resource.py
+++ b/synapse/rest/media/v1/preview_url_resource.py
@@ -23,7 +23,8 @@ import re
 import shutil
 import sys
 import traceback
-import simplejson as json
+
+from canonicaljson import json
 
 from six.moves import urllib_parse as urlparse
 from six import string_types
diff --git a/synapse/storage/__init__.py b/synapse/storage/__init__.py
index 979fa22438..e843b702b9 100644
--- a/synapse/storage/__init__.py
+++ b/synapse/storage/__init__.py
@@ -20,6 +20,7 @@ import time
 import logging
 
 from synapse.storage.devices import DeviceStore
+from synapse.storage.user_erasure_store import UserErasureStore
 from .appservice import (
     ApplicationServiceStore, ApplicationServiceTransactionStore
 )
@@ -88,6 +89,7 @@ class DataStore(RoomMemberStore, RoomStore,
                 DeviceInboxStore,
                 UserDirectoryStore,
                 GroupServerStore,
+                UserErasureStore,
                 ):
 
     def __init__(self, db_conn, hs):
diff --git a/synapse/storage/account_data.py b/synapse/storage/account_data.py
index 284ec3c970..7034a61399 100644
--- a/synapse/storage/account_data.py
+++ b/synapse/storage/account_data.py
@@ -22,8 +22,9 @@ from synapse.storage.util.id_generators import StreamIdGenerator
 from synapse.util.caches.stream_change_cache import StreamChangeCache
 from synapse.util.caches.descriptors import cached, cachedInlineCallbacks
 
+from canonicaljson import json
+
 import abc
-import simplejson as json
 import logging
 
 logger = logging.getLogger(__name__)
diff --git a/synapse/storage/appservice.py b/synapse/storage/appservice.py
index 12ea8a158c..4d32d0bdf6 100644
--- a/synapse/storage/appservice.py
+++ b/synapse/storage/appservice.py
@@ -15,8 +15,8 @@
 # limitations under the License.
 import logging
 import re
-import simplejson as json
 from twisted.internet import defer
+from canonicaljson import json
 
 from synapse.appservice import AppServiceTransaction
 from synapse.config.appservice import load_appservices
diff --git a/synapse/storage/background_updates.py b/synapse/storage/background_updates.py
index b7e9c716c8..af18964510 100644
--- a/synapse/storage/background_updates.py
+++ b/synapse/storage/background_updates.py
@@ -18,7 +18,8 @@ from . import engines
 
 from twisted.internet import defer
 
-import simplejson as json
+from canonicaljson import json
+
 import logging
 
 logger = logging.getLogger(__name__)
diff --git a/synapse/storage/deviceinbox.py b/synapse/storage/deviceinbox.py
index a879e5bfc1..38addbf9c0 100644
--- a/synapse/storage/deviceinbox.py
+++ b/synapse/storage/deviceinbox.py
@@ -14,7 +14,8 @@
 # limitations under the License.
 
 import logging
-import simplejson
+
+from canonicaljson import json
 
 from twisted.internet import defer
 
@@ -85,7 +86,7 @@ class DeviceInboxStore(BackgroundUpdateStore):
             )
             rows = []
             for destination, edu in remote_messages_by_destination.items():
-                edu_json = simplejson.dumps(edu)
+                edu_json = json.dumps(edu)
                 rows.append((destination, stream_id, now_ms, edu_json))
             txn.executemany(sql, rows)
 
@@ -177,7 +178,7 @@ class DeviceInboxStore(BackgroundUpdateStore):
                     " WHERE user_id = ?"
                 )
                 txn.execute(sql, (user_id,))
-                message_json = simplejson.dumps(messages_by_device["*"])
+                message_json = json.dumps(messages_by_device["*"])
                 for row in txn:
                     # Add the message for all devices for this user on this
                     # server.
@@ -199,7 +200,7 @@ class DeviceInboxStore(BackgroundUpdateStore):
                     # Only insert into the local inbox if the device exists on
                     # this server
                     device = row[0]
-                    message_json = simplejson.dumps(messages_by_device[device])
+                    message_json = json.dumps(messages_by_device[device])
                     messages_json_for_user[device] = message_json
 
             if messages_json_for_user:
@@ -253,7 +254,7 @@ class DeviceInboxStore(BackgroundUpdateStore):
             messages = []
             for row in txn:
                 stream_pos = row[0]
-                messages.append(simplejson.loads(row[1]))
+                messages.append(json.loads(row[1]))
             if len(messages) < limit:
                 stream_pos = current_stream_id
             return (messages, stream_pos)
@@ -389,7 +390,7 @@ class DeviceInboxStore(BackgroundUpdateStore):
             messages = []
             for row in txn:
                 stream_pos = row[0]
-                messages.append(simplejson.loads(row[1]))
+                messages.append(json.loads(row[1]))
             if len(messages) < limit:
                 stream_pos = current_stream_id
             return (messages, stream_pos)
diff --git a/synapse/storage/devices.py b/synapse/storage/devices.py
index d149d8392e..2ed9ada783 100644
--- a/synapse/storage/devices.py
+++ b/synapse/storage/devices.py
@@ -13,7 +13,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import logging
-import simplejson as json
 
 from twisted.internet import defer
 
@@ -21,6 +20,8 @@ from synapse.api.errors import StoreError
 from ._base import SQLBaseStore, Cache
 from synapse.util.caches.descriptors import cached, cachedList, cachedInlineCallbacks
 
+from canonicaljson import json
+
 from six import itervalues, iteritems
 
 logger = logging.getLogger(__name__)
diff --git a/synapse/storage/end_to_end_keys.py b/synapse/storage/end_to_end_keys.py
index b146487943..181047c8b7 100644
--- a/synapse/storage/end_to_end_keys.py
+++ b/synapse/storage/end_to_end_keys.py
@@ -16,8 +16,7 @@ from twisted.internet import defer
 
 from synapse.util.caches.descriptors import cached
 
-from canonicaljson import encode_canonical_json
-import simplejson as json
+from canonicaljson import encode_canonical_json, json
 
 from ._base import SQLBaseStore
 
diff --git a/synapse/storage/event_push_actions.py b/synapse/storage/event_push_actions.py
index 8cb24b7d59..05cb3f61ce 100644
--- a/synapse/storage/event_push_actions.py
+++ b/synapse/storage/event_push_actions.py
@@ -19,7 +19,8 @@ from twisted.internet import defer
 from synapse.util.caches.descriptors import cachedInlineCallbacks
 
 import logging
-import simplejson as json
+
+from canonicaljson import json
 
 from six import iteritems
 
diff --git a/synapse/storage/events.py b/synapse/storage/events.py
index 7d0e59538a..a54abb9edd 100644
--- a/synapse/storage/events.py
+++ b/synapse/storage/events.py
@@ -19,7 +19,8 @@ from functools import wraps
 import itertools
 import logging
 
-import simplejson as json
+from canonicaljson import json
+
 from twisted.internet import defer
 
 from synapse.storage.events_worker import EventsWorkerStore
@@ -800,7 +801,8 @@ class EventsStore(EventsWorkerStore):
                     ]
                 )
 
-                self._curr_state_delta_stream_cache.entity_has_changed(
+                txn.call_after(
+                    self._curr_state_delta_stream_cache.entity_has_changed,
                     room_id, max_stream_order,
                 )
 
diff --git a/synapse/storage/events_worker.py b/synapse/storage/events_worker.py
index f6a6e46b43..896225aab9 100644
--- a/synapse/storage/events_worker.py
+++ b/synapse/storage/events_worker.py
@@ -29,7 +29,8 @@ from synapse.api.errors import SynapseError
 from collections import namedtuple
 
 import logging
-import simplejson as json
+
+from canonicaljson import json
 
 # these are only included to make the type annotations work
 from synapse.events import EventBase    # noqa: F401
diff --git a/synapse/storage/filtering.py b/synapse/storage/filtering.py
index 2e2763126d..eae6027cee 100644
--- a/synapse/storage/filtering.py
+++ b/synapse/storage/filtering.py
@@ -19,8 +19,7 @@ from ._base import SQLBaseStore
 from synapse.api.errors import SynapseError, Codes
 from synapse.util.caches.descriptors import cachedInlineCallbacks
 
-from canonicaljson import encode_canonical_json
-import simplejson as json
+from canonicaljson import encode_canonical_json, json
 
 
 class FilteringStore(SQLBaseStore):
diff --git a/synapse/storage/group_server.py b/synapse/storage/group_server.py
index da05ccb027..b77402d295 100644
--- a/synapse/storage/group_server.py
+++ b/synapse/storage/group_server.py
@@ -20,7 +20,7 @@ from synapse.api.errors import SynapseError
 
 from ._base import SQLBaseStore
 
-import simplejson as json
+from canonicaljson import json
 
 
 # The category ID for the "default" category. We don't store as null in the
diff --git a/synapse/storage/push_rule.py b/synapse/storage/push_rule.py
index 04a0b59a39..9e52e992b3 100644
--- a/synapse/storage/push_rule.py
+++ b/synapse/storage/push_rule.py
@@ -25,9 +25,10 @@ from synapse.push.baserules import list_with_base_rules
 from synapse.api.constants import EventTypes
 from twisted.internet import defer
 
+from canonicaljson import json
+
 import abc
 import logging
-import simplejson as json
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/storage/pusher.py b/synapse/storage/pusher.py
index 307660b99a..c6def861cf 100644
--- a/synapse/storage/pusher.py
+++ b/synapse/storage/pusher.py
@@ -17,12 +17,11 @@
 from ._base import SQLBaseStore
 from twisted.internet import defer
 
-from canonicaljson import encode_canonical_json
+from canonicaljson import encode_canonical_json, json
 
 from synapse.util.caches.descriptors import cachedInlineCallbacks, cachedList
 
 import logging
-import simplejson as json
 import types
 
 logger = logging.getLogger(__name__)
diff --git a/synapse/storage/receipts.py b/synapse/storage/receipts.py
index c93c228f6e..f230a3bab7 100644
--- a/synapse/storage/receipts.py
+++ b/synapse/storage/receipts.py
@@ -21,9 +21,10 @@ from synapse.util.caches.stream_change_cache import StreamChangeCache
 
 from twisted.internet import defer
 
+from canonicaljson import json
+
 import abc
 import logging
-import simplejson as json
 
 
 logger = logging.getLogger(__name__)
diff --git a/synapse/storage/registration.py b/synapse/storage/registration.py
index 9c9cf46e7f..0d18f6d869 100644
--- a/synapse/storage/registration.py
+++ b/synapse/storage/registration.py
@@ -623,7 +623,9 @@ class RegistrationStore(RegistrationWorkerStore,
         Removes the given user to the table of users who need to be parted from all the
         rooms they're in, effectively marking that user as fully deactivated.
         """
-        return self._simple_delete_one(
+        # XXX: This should be simple_delete_one but we failed to put a unique index on
+        # the table, so somehow duplicate entries have ended up in it.
+        return self._simple_delete(
             "users_pending_deactivation",
             keyvalues={
                 "user_id": user_id,
diff --git a/synapse/storage/room.py b/synapse/storage/room.py
index ea6a189185..ca0eb187e5 100644
--- a/synapse/storage/room.py
+++ b/synapse/storage/room.py
@@ -20,9 +20,10 @@ from synapse.storage._base import SQLBaseStore
 from synapse.storage.search import SearchStore
 from synapse.util.caches.descriptors import cached, cachedInlineCallbacks
 
+from canonicaljson import json
+
 import collections
 import logging
-import simplejson as json
 import re
 
 logger = logging.getLogger(__name__)
diff --git a/synapse/storage/roommember.py b/synapse/storage/roommember.py
index 829cc4a207..8fc9549a75 100644
--- a/synapse/storage/roommember.py
+++ b/synapse/storage/roommember.py
@@ -28,7 +28,7 @@ from synapse.api.constants import Membership, EventTypes
 from synapse.types import get_domain_from_id
 
 import logging
-import simplejson as json
+from canonicaljson import json
 
 from six import itervalues, iteritems
 
diff --git a/synapse/storage/schema/delta/50/erasure_store.sql b/synapse/storage/schema/delta/50/erasure_store.sql
new file mode 100644
index 0000000000..5d8641a9ab
--- /dev/null
+++ b/synapse/storage/schema/delta/50/erasure_store.sql
@@ -0,0 +1,21 @@
+/* Copyright 2018 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.
+ * 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.
+ */
+
+-- a table of users who have requested that their details be erased
+CREATE TABLE erased_users (
+    user_id TEXT NOT NULL
+);
+
+CREATE UNIQUE INDEX erased_users_user ON erased_users(user_id);
diff --git a/synapse/storage/search.py b/synapse/storage/search.py
index f0fa5d7631..9b77c45318 100644
--- a/synapse/storage/search.py
+++ b/synapse/storage/search.py
@@ -16,7 +16,7 @@
 from collections import namedtuple
 import logging
 import re
-import simplejson as json
+from canonicaljson import json
 
 from six import string_types
 
diff --git a/synapse/storage/tags.py b/synapse/storage/tags.py
index 6671d3cfca..04d123ed95 100644
--- a/synapse/storage/tags.py
+++ b/synapse/storage/tags.py
@@ -19,7 +19,8 @@ from synapse.storage.account_data import AccountDataWorkerStore
 from synapse.util.caches.descriptors import cached
 from twisted.internet import defer
 
-import simplejson as json
+from canonicaljson import json
+
 import logging
 
 from six.moves import range
diff --git a/synapse/storage/transactions.py b/synapse/storage/transactions.py
index e485d19b84..acbc03446e 100644
--- a/synapse/storage/transactions.py
+++ b/synapse/storage/transactions.py
@@ -19,12 +19,11 @@ from synapse.util.caches.descriptors import cached
 from twisted.internet import defer
 import six
 
-from canonicaljson import encode_canonical_json
+from canonicaljson import encode_canonical_json, json
 
 from collections import namedtuple
 
 import logging
-import simplejson as json
 
 # py2 sqlite has buffer hardcoded as only binary type, so we must use it,
 # despite being deprecated and removed in favor of memoryview
diff --git a/synapse/storage/user_erasure_store.py b/synapse/storage/user_erasure_store.py
new file mode 100644
index 0000000000..47bfc01e84
--- /dev/null
+++ b/synapse/storage/user_erasure_store.py
@@ -0,0 +1,103 @@
+# -*- coding: utf-8 -*-
+# Copyright 2018 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.
+# 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 operator
+
+from twisted.internet import defer
+
+from synapse.storage._base import SQLBaseStore
+from synapse.util.caches.descriptors import cachedList, cached
+
+
+class UserErasureWorkerStore(SQLBaseStore):
+    @cached()
+    def is_user_erased(self, user_id):
+        """
+        Check if the given user id has requested erasure
+
+        Args:
+            user_id (str): full user id to check
+
+        Returns:
+            Deferred[bool]: True if the user has requested erasure
+        """
+        return self._simple_select_onecol(
+            table="erased_users",
+            keyvalues={"user_id": user_id},
+            retcol="1",
+            desc="is_user_erased",
+        ).addCallback(operator.truth)
+
+    @cachedList(
+        cached_method_name="is_user_erased",
+        list_name="user_ids",
+        inlineCallbacks=True,
+    )
+    def are_users_erased(self, user_ids):
+        """
+        Checks which users in a list have requested erasure
+
+        Args:
+            user_ids (iterable[str]): full user id to check
+
+        Returns:
+            Deferred[dict[str, bool]]:
+                for each user, whether the user has requested erasure.
+        """
+        # this serves the dual purpose of (a) making sure we can do len and
+        # iterate it multiple times, and (b) avoiding duplicates.
+        user_ids = tuple(set(user_ids))
+
+        def _get_erased_users(txn):
+            txn.execute(
+                "SELECT user_id FROM erased_users WHERE user_id IN (%s)" % (
+                    ",".join("?" * len(user_ids))
+                ),
+                user_ids,
+            )
+            return set(r[0] for r in txn)
+
+        erased_users = yield self.runInteraction(
+            "are_users_erased", _get_erased_users,
+        )
+        res = dict((u, u in erased_users) for u in user_ids)
+        defer.returnValue(res)
+
+
+class UserErasureStore(UserErasureWorkerStore):
+    def mark_user_erased(self, user_id):
+        """Indicate that user_id wishes their message history to be erased.
+
+        Args:
+            user_id (str): full user_id to be erased
+        """
+        def f(txn):
+            # first check if they are already in the list
+            txn.execute(
+                "SELECT 1 FROM erased_users WHERE user_id = ?",
+                (user_id, )
+            )
+            if txn.fetchone():
+                return
+
+            # they are not already there: do the insert.
+            txn.execute(
+                "INSERT INTO erased_users (user_id) VALUES (?)",
+                (user_id, )
+            )
+
+            self._invalidate_cache_and_stream(
+                txn, self.is_user_erased, (user_id,)
+            )
+        return self.runInteraction("mark_user_erased", f)
diff --git a/synapse/util/__init__.py b/synapse/util/__init__.py
index 2a3df7c71d..e9886ef299 100644
--- a/synapse/util/__init__.py
+++ b/synapse/util/__init__.py
@@ -34,6 +34,9 @@ def unwrapFirstError(failure):
 class Clock(object):
     """
     A Clock wraps a Twisted reactor and provides utilities on top of it.
+
+    Args:
+        reactor: The Twisted reactor to use.
     """
     _reactor = attr.ib()
 
diff --git a/synapse/util/caches/stream_change_cache.py b/synapse/util/caches/stream_change_cache.py
index 817118e30f..0fb8620001 100644
--- a/synapse/util/caches/stream_change_cache.py
+++ b/synapse/util/caches/stream_change_cache.py
@@ -78,7 +78,8 @@ class StreamChangeCache(object):
             not_known_entities = set(entities) - set(self._entity_to_key)
 
             result = (
-                set(self._cache.values()[self._cache.bisect_right(stream_pos) :])
+                {self._cache[k] for k in self._cache.islice(
+                    start=self._cache.bisect_right(stream_pos))}
                 .intersection(entities)
                 .union(not_known_entities)
             )
@@ -113,7 +114,8 @@ class StreamChangeCache(object):
         assert type(stream_pos) is int
 
         if stream_pos >= self._earliest_known_stream_pos:
-            return self._cache.values()[self._cache.bisect_right(stream_pos) :]
+            return [self._cache[k] for k in self._cache.islice(
+                start=self._cache.bisect_right(stream_pos))]
         else:
             return None
 
diff --git a/synapse/util/frozenutils.py b/synapse/util/frozenutils.py
index 15f0a7ba9e..535e7d0e7a 100644
--- a/synapse/util/frozenutils.py
+++ b/synapse/util/frozenutils.py
@@ -14,7 +14,7 @@
 # limitations under the License.
 
 from frozendict import frozendict
-import simplejson as json
+from canonicaljson import json
 
 from six import string_types
 
diff --git a/synapse/visibility.py b/synapse/visibility.py
index aef4953c1d..65d79cf0d0 100644
--- a/synapse/visibility.py
+++ b/synapse/visibility.py
@@ -12,15 +12,17 @@
 # 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 itertools
 import logging
+import operator
 
 from twisted.internet import defer
 
-from synapse.api.constants import Membership, EventTypes
-
-from synapse.util.logcontext import make_deferred_yieldable, preserve_fn
-
+from synapse.api.constants import EventTypes, Membership
+from synapse.events.utils import prune_event
+from synapse.util.logcontext import (
+    make_deferred_yieldable, preserve_fn,
+)
 
 logger = logging.getLogger(__name__)
 
@@ -95,16 +97,27 @@ def filter_events_for_client(store, user_id, events, is_peeking=False,
         if ignore_dict_content else []
     )
 
+    erased_senders = yield store.are_users_erased((e.sender for e in events))
+
     def allowed(event):
         """
         Args:
             event (synapse.events.EventBase): event to check
+
+        Returns:
+            None|EventBase:
+               None if the user cannot see this event at all
+
+               a redacted copy of the event if they can only see a redacted
+               version
+
+               the original event if they can see it as normal.
         """
         if not event.is_state() and event.sender in ignore_list:
-            return False
+            return None
 
         if event.event_id in always_include_ids:
-            return True
+            return event
 
         state = event_id_to_state[event.event_id]
 
@@ -118,10 +131,6 @@ def filter_events_for_client(store, user_id, events, is_peeking=False,
         if visibility not in VISIBILITY_PRIORITY:
             visibility = "shared"
 
-        # if it was world_readable, it's easy: everyone can read it
-        if visibility == "world_readable":
-            return True
-
         # Always allow history visibility events on boundaries. This is done
         # by setting the effective visibility to the least restrictive
         # of the old vs new.
@@ -155,7 +164,7 @@ def filter_events_for_client(store, user_id, events, is_peeking=False,
             if membership == "leave" and (
                 prev_membership == "join" or prev_membership == "invite"
             ):
-                return True
+                return event
 
             new_priority = MEMBERSHIP_PRIORITY.index(membership)
             old_priority = MEMBERSHIP_PRIORITY.index(prev_membership)
@@ -166,31 +175,55 @@ def filter_events_for_client(store, user_id, events, is_peeking=False,
         if membership is None:
             membership_event = state.get((EventTypes.Member, user_id), None)
             if membership_event:
+                # XXX why do we do this?
+                # https://github.com/matrix-org/synapse/issues/3350
                 if membership_event.event_id not in event_id_forgotten:
                     membership = membership_event.membership
 
         # if the user was a member of the room at the time of the event,
         # they can see it.
         if membership == Membership.JOIN:
-            return True
+            return event
+
+        # otherwise, it depends on the room visibility.
 
         if visibility == "joined":
             # we weren't a member at the time of the event, so we can't
             # see this event.
-            return False
+            return None
 
         elif visibility == "invited":
             # user can also see the event if they were *invited* at the time
             # of the event.
-            return membership == Membership.INVITE
-
-        else:
-            # visibility is shared: user can also see the event if they have
-            # become a member since the event
+            return (
+                event if membership == Membership.INVITE else None
+            )
+
+        elif visibility == "shared" and is_peeking:
+            # if the visibility is shared, users cannot see the event unless
+            # they have *subequently* joined the room (or were members at the
+            # time, of course)
             #
             # XXX: if the user has subsequently joined and then left again,
             # ideally we would share history up to the point they left. But
-            # we don't know when they left.
-            return not is_peeking
+            # we don't know when they left. We just treat it as though they
+            # never joined, and restrict access.
+            return None
+
+        # the visibility is either shared or world_readable, and the user was
+        # not a member at the time. We allow it, provided the original sender
+        # has not requested their data to be erased, in which case, we return
+        # a redacted version.
+        if erased_senders[event.sender]:
+            return prune_event(event)
+
+        return event
+
+    # check each event: gives an iterable[None|EventBase]
+    filtered_events = itertools.imap(allowed, events)
+
+    # remove the None entries
+    filtered_events = filter(operator.truth, filtered_events)
 
-    defer.returnValue(list(filter(allowed, events)))
+    # we turn it into a list before returning it.
+    defer.returnValue(list(filtered_events))
diff --git a/tests/api/test_auth.py b/tests/api/test_auth.py
index 4575dd9834..aec3b62897 100644
--- a/tests/api/test_auth.py
+++ b/tests/api/test_auth.py
@@ -86,16 +86,53 @@ class AuthTestCase(unittest.TestCase):
 
     @defer.inlineCallbacks
     def test_get_user_by_req_appservice_valid_token(self):
-        app_service = Mock(token="foobar", url="a_url", sender=self.test_user)
+        app_service = Mock(
+            token="foobar", url="a_url", sender=self.test_user,
+            ip_range_whitelist=None,
+        )
+        self.store.get_app_service_by_token = Mock(return_value=app_service)
+        self.store.get_user_by_access_token = Mock(return_value=None)
+
+        request = Mock(args={})
+        request.getClientIP.return_value = "127.0.0.1"
+        request.args["access_token"] = [self.test_token]
+        request.requestHeaders.getRawHeaders = mock_getRawHeaders()
+        requester = yield self.auth.get_user_by_req(request)
+        self.assertEquals(requester.user.to_string(), self.test_user)
+
+    @defer.inlineCallbacks
+    def test_get_user_by_req_appservice_valid_token_good_ip(self):
+        from netaddr import IPSet
+        app_service = Mock(
+            token="foobar", url="a_url", sender=self.test_user,
+            ip_range_whitelist=IPSet(["192.168/16"]),
+        )
         self.store.get_app_service_by_token = Mock(return_value=app_service)
         self.store.get_user_by_access_token = Mock(return_value=None)
 
         request = Mock(args={})
+        request.getClientIP.return_value = "192.168.10.10"
         request.args["access_token"] = [self.test_token]
         request.requestHeaders.getRawHeaders = mock_getRawHeaders()
         requester = yield self.auth.get_user_by_req(request)
         self.assertEquals(requester.user.to_string(), self.test_user)
 
+    def test_get_user_by_req_appservice_valid_token_bad_ip(self):
+        from netaddr import IPSet
+        app_service = Mock(
+            token="foobar", url="a_url", sender=self.test_user,
+            ip_range_whitelist=IPSet(["192.168/16"]),
+        )
+        self.store.get_app_service_by_token = Mock(return_value=app_service)
+        self.store.get_user_by_access_token = Mock(return_value=None)
+
+        request = Mock(args={})
+        request.getClientIP.return_value = "131.111.8.42"
+        request.args["access_token"] = [self.test_token]
+        request.requestHeaders.getRawHeaders = mock_getRawHeaders()
+        d = self.auth.get_user_by_req(request)
+        self.failureResultOf(d, AuthError)
+
     def test_get_user_by_req_appservice_bad_token(self):
         self.store.get_app_service_by_token = Mock(return_value=None)
         self.store.get_user_by_access_token = Mock(return_value=None)
@@ -119,12 +156,16 @@ class AuthTestCase(unittest.TestCase):
     @defer.inlineCallbacks
     def test_get_user_by_req_appservice_valid_token_valid_user_id(self):
         masquerading_user_id = "@doppelganger:matrix.org"
-        app_service = Mock(token="foobar", url="a_url", sender=self.test_user)
+        app_service = Mock(
+            token="foobar", url="a_url", sender=self.test_user,
+            ip_range_whitelist=None,
+        )
         app_service.is_interested_in_user = Mock(return_value=True)
         self.store.get_app_service_by_token = Mock(return_value=app_service)
         self.store.get_user_by_access_token = Mock(return_value=None)
 
         request = Mock(args={})
+        request.getClientIP.return_value = "127.0.0.1"
         request.args["access_token"] = [self.test_token]
         request.args["user_id"] = [masquerading_user_id]
         request.requestHeaders.getRawHeaders = mock_getRawHeaders()
@@ -133,12 +174,16 @@ class AuthTestCase(unittest.TestCase):
 
     def test_get_user_by_req_appservice_valid_token_bad_user_id(self):
         masquerading_user_id = "@doppelganger:matrix.org"
-        app_service = Mock(token="foobar", url="a_url", sender=self.test_user)
+        app_service = Mock(
+            token="foobar", url="a_url", sender=self.test_user,
+            ip_range_whitelist=None,
+        )
         app_service.is_interested_in_user = Mock(return_value=False)
         self.store.get_app_service_by_token = Mock(return_value=app_service)
         self.store.get_user_by_access_token = Mock(return_value=None)
 
         request = Mock(args={})
+        request.getClientIP.return_value = "127.0.0.1"
         request.args["access_token"] = [self.test_token]
         request.args["user_id"] = [masquerading_user_id]
         request.requestHeaders.getRawHeaders = mock_getRawHeaders()
diff --git a/tests/federation/__init__.py b/tests/federation/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/tests/federation/__init__.py
diff --git a/tests/federation/test_federation_server.py b/tests/federation/test_federation_server.py
new file mode 100644
index 0000000000..4e8dc8fea0
--- /dev/null
+++ b/tests/federation/test_federation_server.py
@@ -0,0 +1,57 @@
+# -*- coding: utf-8 -*-
+# Copyright 2018 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.
+# 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.events import FrozenEvent
+from synapse.federation.federation_server import server_matches_acl_event
+from tests import unittest
+
+
+@unittest.DEBUG
+class ServerACLsTestCase(unittest.TestCase):
+    def test_blacklisted_server(self):
+        e = _create_acl_event({
+            "allow": ["*"],
+            "deny": ["evil.com"],
+        })
+        logging.info("ACL event: %s", e.content)
+
+        self.assertFalse(server_matches_acl_event("evil.com", e))
+        self.assertFalse(server_matches_acl_event("EVIL.COM", e))
+
+        self.assertTrue(server_matches_acl_event("evil.com.au", e))
+        self.assertTrue(server_matches_acl_event("honestly.not.evil.com", e))
+
+    def test_block_ip_literals(self):
+        e = _create_acl_event({
+            "allow_ip_literals": False,
+            "allow": ["*"],
+        })
+        logging.info("ACL event: %s", e.content)
+
+        self.assertFalse(server_matches_acl_event("1.2.3.4", e))
+        self.assertTrue(server_matches_acl_event("1a.2.3.4", e))
+        self.assertFalse(server_matches_acl_event("[1:2::]", e))
+        self.assertTrue(server_matches_acl_event("1:2:3:4", e))
+
+
+def _create_acl_event(content):
+    return FrozenEvent({
+        "room_id": "!a:b",
+        "event_id": "$a:b",
+        "type": "m.room.server_acls",
+        "sender": "@a:b",
+        "content": content
+    })
diff --git a/tests/http/__init__.py b/tests/http/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/tests/http/__init__.py
diff --git a/tests/http/test_endpoint.py b/tests/http/test_endpoint.py
new file mode 100644
index 0000000000..b8a48d20a4
--- /dev/null
+++ b/tests/http/test_endpoint.py
@@ -0,0 +1,55 @@
+# -*- coding: utf-8 -*-
+# Copyright 2018 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.
+# 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.
+from synapse.http.endpoint import (
+    parse_server_name,
+    parse_and_validate_server_name,
+)
+from tests import unittest
+
+
+class ServerNameTestCase(unittest.TestCase):
+    def test_parse_server_name(self):
+        test_data = {
+            'localhost': ('localhost', None),
+            'my-example.com:1234': ('my-example.com', 1234),
+            '1.2.3.4': ('1.2.3.4', None),
+            '[0abc:1def::1234]': ('[0abc:1def::1234]', None),
+            '1.2.3.4:1': ('1.2.3.4', 1),
+            '[0abc:1def::1234]:8080': ('[0abc:1def::1234]', 8080),
+        }
+
+        for i, o in test_data.items():
+            self.assertEqual(parse_server_name(i), o)
+
+    def test_validate_bad_server_names(self):
+        test_data = [
+            "",  # empty
+            "localhost:http",  # non-numeric port
+            "1234]",  # smells like ipv6 literal but isn't
+            "[1234",
+            "underscore_.com",
+            "percent%65.com",
+            "1234:5678:80",   # too many colons
+        ]
+        for i in test_data:
+            try:
+                parse_and_validate_server_name(i)
+                self.fail(
+                    "Expected parse_and_validate_server_name('%s') to throw" % (
+                        i,
+                    ),
+                )
+            except ValueError:
+                pass
diff --git a/tests/server.py b/tests/server.py
new file mode 100644
index 0000000000..73069dff52
--- /dev/null
+++ b/tests/server.py
@@ -0,0 +1,181 @@
+from io import BytesIO
+
+import attr
+import json
+from six import text_type
+
+from twisted.python.failure import Failure
+from twisted.internet.defer import Deferred
+from twisted.test.proto_helpers import MemoryReactorClock
+
+from synapse.http.site import SynapseRequest
+from twisted.internet import threads
+from tests.utils import setup_test_homeserver as _sth
+
+
+@attr.s
+class FakeChannel(object):
+    """
+    A fake Twisted Web Channel (the part that interfaces with the
+    wire).
+    """
+
+    result = attr.ib(factory=dict)
+
+    @property
+    def json_body(self):
+        if not self.result:
+            raise Exception("No result yet.")
+        return json.loads(self.result["body"])
+
+    def writeHeaders(self, version, code, reason, headers):
+        self.result["version"] = version
+        self.result["code"] = code
+        self.result["reason"] = reason
+        self.result["headers"] = headers
+
+    def write(self, content):
+        if "body" not in self.result:
+            self.result["body"] = b""
+
+        self.result["body"] += content
+
+    def requestDone(self, _self):
+        self.result["done"] = True
+
+    def getPeer(self):
+        return None
+
+    def getHost(self):
+        return None
+
+    @property
+    def transport(self):
+        return self
+
+
+class FakeSite:
+    """
+    A fake Twisted Web Site, with mocks of the extra things that
+    Synapse adds.
+    """
+
+    server_version_string = b"1"
+    site_tag = "test"
+
+    @property
+    def access_logger(self):
+        class FakeLogger:
+            def info(self, *args, **kwargs):
+                pass
+
+        return FakeLogger()
+
+
+def make_request(method, path, content=b""):
+    """
+    Make a web request using the given method and path, feed it the
+    content, and return the Request and the Channel underneath.
+    """
+
+    if isinstance(content, text_type):
+        content = content.encode('utf8')
+
+    site = FakeSite()
+    channel = FakeChannel()
+
+    req = SynapseRequest(site, channel)
+    req.process = lambda: b""
+    req.content = BytesIO(content)
+    req.requestReceived(method, path, b"1.1")
+
+    return req, channel
+
+
+def wait_until_result(clock, channel, timeout=100):
+    """
+    Wait until the channel has a result.
+    """
+    clock.run()
+    x = 0
+
+    while not channel.result:
+        x += 1
+
+        if x > timeout:
+            raise Exception("Timed out waiting for request to finish.")
+
+        clock.advance(0.1)
+
+
+class ThreadedMemoryReactorClock(MemoryReactorClock):
+    """
+    A MemoryReactorClock that supports callFromThread.
+    """
+    def callFromThread(self, callback, *args, **kwargs):
+        """
+        Make the callback fire in the next reactor iteration.
+        """
+        d = Deferred()
+        d.addCallback(lambda x: callback(*args, **kwargs))
+        self.callLater(0, d.callback, True)
+        return d
+
+
+def setup_test_homeserver(*args, **kwargs):
+    """
+    Set up a synchronous test server, driven by the reactor used by
+    the homeserver.
+    """
+    d = _sth(*args, **kwargs).result
+
+    # Make the thread pool synchronous.
+    clock = d.get_clock()
+    pool = d.get_db_pool()
+
+    def runWithConnection(func, *args, **kwargs):
+        return threads.deferToThreadPool(
+            pool._reactor,
+            pool.threadpool,
+            pool._runWithConnection,
+            func,
+            *args,
+            **kwargs
+        )
+
+    def runInteraction(interaction, *args, **kwargs):
+        return threads.deferToThreadPool(
+            pool._reactor,
+            pool.threadpool,
+            pool._runInteraction,
+            interaction,
+            *args,
+            **kwargs
+        )
+
+    pool.runWithConnection = runWithConnection
+    pool.runInteraction = runInteraction
+
+    class ThreadPool:
+        """
+        Threadless thread pool.
+        """
+        def start(self):
+            pass
+
+        def callInThreadWithCallback(self, onResult, function, *args, **kwargs):
+            def _(res):
+                if isinstance(res, Failure):
+                    onResult(False, res)
+                else:
+                    onResult(True, res)
+
+            d = Deferred()
+            d.addCallback(lambda x: function(*args, **kwargs))
+            d.addBoth(_)
+            clock._reactor.callLater(0, d.callback, True)
+            return d
+
+    clock.threadpool = ThreadPool()
+    pool.threadpool = ThreadPool()
+    return d
diff --git a/tests/test_federation.py b/tests/test_federation.py
new file mode 100644
index 0000000000..fc80a69369
--- /dev/null
+++ b/tests/test_federation.py
@@ -0,0 +1,243 @@
+
+from twisted.internet.defer import succeed, maybeDeferred
+
+from synapse.util import Clock
+from synapse.events import FrozenEvent
+from synapse.types import Requester, UserID
+
+from tests import unittest
+from tests.server import setup_test_homeserver, ThreadedMemoryReactorClock
+
+from mock import Mock
+
+
+class MessageAcceptTests(unittest.TestCase):
+    def setUp(self):
+
+        self.http_client = Mock()
+        self.reactor = ThreadedMemoryReactorClock()
+        self.hs_clock = Clock(self.reactor)
+        self.homeserver = setup_test_homeserver(
+            http_client=self.http_client, clock=self.hs_clock, reactor=self.reactor
+        )
+
+        user_id = UserID("us", "test")
+        our_user = Requester(user_id, None, False, None, None)
+        room_creator = self.homeserver.get_room_creation_handler()
+        room = room_creator.create_room(
+            our_user, room_creator.PRESETS_DICT["public_chat"], ratelimit=False
+        )
+        self.reactor.advance(0.1)
+        self.room_id = self.successResultOf(room)["room_id"]
+
+        # Figure out what the most recent event is
+        most_recent = self.successResultOf(
+            maybeDeferred(
+                self.homeserver.datastore.get_latest_event_ids_in_room, self.room_id
+            )
+        )[0]
+
+        join_event = FrozenEvent(
+            {
+                "room_id": self.room_id,
+                "sender": "@baduser:test.serv",
+                "state_key": "@baduser:test.serv",
+                "event_id": "$join:test.serv",
+                "depth": 1000,
+                "origin_server_ts": 1,
+                "type": "m.room.member",
+                "origin": "test.servx",
+                "content": {"membership": "join"},
+                "auth_events": [],
+                "prev_state": [(most_recent, {})],
+                "prev_events": [(most_recent, {})],
+            }
+        )
+
+        self.handler = self.homeserver.get_handlers().federation_handler
+        self.handler.do_auth = lambda *a, **b: succeed(True)
+        self.client = self.homeserver.get_federation_client()
+        self.client._check_sigs_and_hash_and_fetch = lambda dest, pdus, **k: succeed(
+            pdus
+        )
+
+        # Send the join, it should return None (which is not an error)
+        d = self.handler.on_receive_pdu(
+            "test.serv", join_event, sent_to_us_directly=True
+        )
+        self.reactor.advance(1)
+        self.assertEqual(self.successResultOf(d), None)
+
+        # Make sure we actually joined the room
+        self.assertEqual(
+            self.successResultOf(
+                maybeDeferred(
+                    self.homeserver.datastore.get_latest_event_ids_in_room, self.room_id
+                )
+            )[0],
+            "$join:test.serv",
+        )
+
+    def test_cant_hide_direct_ancestors(self):
+        """
+        If you send a message, you must be able to provide the direct
+        prev_events that said event references.
+        """
+
+        def post_json(destination, path, data, headers=None, timeout=0):
+            # If it asks us for new missing events, give them NOTHING
+            if path.startswith("/_matrix/federation/v1/get_missing_events/"):
+                return {"events": []}
+
+        self.http_client.post_json = post_json
+
+        # Figure out what the most recent event is
+        most_recent = self.successResultOf(
+            maybeDeferred(
+                self.homeserver.datastore.get_latest_event_ids_in_room, self.room_id
+            )
+        )[0]
+
+        # Now lie about an event
+        lying_event = FrozenEvent(
+            {
+                "room_id": self.room_id,
+                "sender": "@baduser:test.serv",
+                "event_id": "one:test.serv",
+                "depth": 1000,
+                "origin_server_ts": 1,
+                "type": "m.room.message",
+                "origin": "test.serv",
+                "content": "hewwo?",
+                "auth_events": [],
+                "prev_events": [("two:test.serv", {}), (most_recent, {})],
+            }
+        )
+
+        d = self.handler.on_receive_pdu(
+            "test.serv", lying_event, sent_to_us_directly=True
+        )
+
+        # Step the reactor, so the database fetches come back
+        self.reactor.advance(1)
+
+        # on_receive_pdu should throw an error
+        failure = self.failureResultOf(d)
+        self.assertEqual(
+            failure.value.args[0],
+            (
+                "ERROR 403: Your server isn't divulging details about prev_events "
+                "referenced in this event."
+            ),
+        )
+
+        # Make sure the invalid event isn't there
+        extrem = maybeDeferred(
+            self.homeserver.datastore.get_latest_event_ids_in_room, self.room_id
+        )
+        self.assertEqual(self.successResultOf(extrem)[0], "$join:test.serv")
+
+    @unittest.DEBUG
+    def test_cant_hide_past_history(self):
+        """
+        If you send a message, you must be able to provide the direct
+        prev_events that said event references.
+        """
+
+        def post_json(destination, path, data, headers=None, timeout=0):
+            if path.startswith("/_matrix/federation/v1/get_missing_events/"):
+                return {
+                    "events": [
+                        {
+                            "room_id": self.room_id,
+                            "sender": "@baduser:test.serv",
+                            "event_id": "three:test.serv",
+                            "depth": 1000,
+                            "origin_server_ts": 1,
+                            "type": "m.room.message",
+                            "origin": "test.serv",
+                            "content": "hewwo?",
+                            "auth_events": [],
+                            "prev_events": [("four:test.serv", {})],
+                        }
+                    ]
+                }
+
+        self.http_client.post_json = post_json
+
+        def get_json(destination, path, args, headers=None):
+            if path.startswith("/_matrix/federation/v1/state_ids/"):
+                d = self.successResultOf(
+                    self.homeserver.datastore.get_state_ids_for_event("one:test.serv")
+                )
+
+                return succeed(
+                    {
+                        "pdu_ids": [
+                            y
+                            for x, y in d.items()
+                            if x == ("m.room.member", "@us:test")
+                        ],
+                        "auth_chain_ids": d.values(),
+                    }
+                )
+
+        self.http_client.get_json = get_json
+
+        # Figure out what the most recent event is
+        most_recent = self.successResultOf(
+            maybeDeferred(
+                self.homeserver.datastore.get_latest_event_ids_in_room, self.room_id
+            )
+        )[0]
+
+        # Make a good event
+        good_event = FrozenEvent(
+            {
+                "room_id": self.room_id,
+                "sender": "@baduser:test.serv",
+                "event_id": "one:test.serv",
+                "depth": 1000,
+                "origin_server_ts": 1,
+                "type": "m.room.message",
+                "origin": "test.serv",
+                "content": "hewwo?",
+                "auth_events": [],
+                "prev_events": [(most_recent, {})],
+            }
+        )
+
+        d = self.handler.on_receive_pdu(
+            "test.serv", good_event, sent_to_us_directly=True
+        )
+        self.reactor.advance(1)
+        self.assertEqual(self.successResultOf(d), None)
+
+        bad_event = FrozenEvent(
+            {
+                "room_id": self.room_id,
+                "sender": "@baduser:test.serv",
+                "event_id": "two:test.serv",
+                "depth": 1000,
+                "origin_server_ts": 1,
+                "type": "m.room.message",
+                "origin": "test.serv",
+                "content": "hewwo?",
+                "auth_events": [],
+                "prev_events": [("one:test.serv", {}), ("three:test.serv", {})],
+            }
+        )
+
+        d = self.handler.on_receive_pdu(
+            "test.serv", bad_event, sent_to_us_directly=True
+        )
+        self.reactor.advance(1)
+
+        extrem = maybeDeferred(
+            self.homeserver.datastore.get_latest_event_ids_in_room, self.room_id
+        )
+        self.assertEqual(self.successResultOf(extrem)[0], "two:test.serv")
+
+        state = self.homeserver.get_state_handler().get_current_state_ids(self.room_id)
+        self.reactor.advance(1)
+        self.assertIn(("m.room.member", "@us:test"), self.successResultOf(state).keys())
diff --git a/tests/test_server.py b/tests/test_server.py
new file mode 100644
index 0000000000..8ad822c43b
--- /dev/null
+++ b/tests/test_server.py
@@ -0,0 +1,128 @@
+import json
+import re
+
+from twisted.internet.defer import Deferred
+from twisted.test.proto_helpers import MemoryReactorClock
+
+from synapse.util import Clock
+from synapse.api.errors import Codes, SynapseError
+from synapse.http.server import JsonResource
+from tests import unittest
+from tests.server import make_request, setup_test_homeserver
+
+
+class JsonResourceTests(unittest.TestCase):
+    def setUp(self):
+        self.reactor = MemoryReactorClock()
+        self.hs_clock = Clock(self.reactor)
+        self.homeserver = setup_test_homeserver(
+            http_client=None, clock=self.hs_clock, reactor=self.reactor
+        )
+
+    def test_handler_for_request(self):
+        """
+        JsonResource.handler_for_request gives correctly decoded URL args to
+        the callback, while Twisted will give the raw bytes of URL query
+        arguments.
+        """
+        got_kwargs = {}
+
+        def _callback(request, **kwargs):
+            got_kwargs.update(kwargs)
+            return (200, kwargs)
+
+        res = JsonResource(self.homeserver)
+        res.register_paths("GET", [re.compile("^/foo/(?P<room_id>[^/]*)$")], _callback)
+
+        request, channel = make_request(b"GET", b"/foo/%E2%98%83?a=%E2%98%83")
+        request.render(res)
+
+        self.assertEqual(request.args, {b'a': [u"\N{SNOWMAN}".encode('utf8')]})
+        self.assertEqual(got_kwargs, {u"room_id": u"\N{SNOWMAN}"})
+
+    def test_callback_direct_exception(self):
+        """
+        If the web callback raises an uncaught exception, it will be translated
+        into a 500.
+        """
+
+        def _callback(request, **kwargs):
+            raise Exception("boo")
+
+        res = JsonResource(self.homeserver)
+        res.register_paths("GET", [re.compile("^/foo$")], _callback)
+
+        request, channel = make_request(b"GET", b"/foo")
+        request.render(res)
+
+        self.assertEqual(channel.result["code"], b'500')
+
+    def test_callback_indirect_exception(self):
+        """
+        If the web callback raises an uncaught exception in a Deferred, it will
+        be translated into a 500.
+        """
+
+        def _throw(*args):
+            raise Exception("boo")
+
+        def _callback(request, **kwargs):
+            d = Deferred()
+            d.addCallback(_throw)
+            self.reactor.callLater(1, d.callback, True)
+            return d
+
+        res = JsonResource(self.homeserver)
+        res.register_paths("GET", [re.compile("^/foo$")], _callback)
+
+        request, channel = make_request(b"GET", b"/foo")
+        request.render(res)
+
+        # No error has been raised yet
+        self.assertTrue("code" not in channel.result)
+
+        # Advance time, now there's an error
+        self.reactor.advance(1)
+        self.assertEqual(channel.result["code"], b'500')
+
+    def test_callback_synapseerror(self):
+        """
+        If the web callback raises a SynapseError, it returns the appropriate
+        status code and message set in it.
+        """
+
+        def _callback(request, **kwargs):
+            raise SynapseError(403, "Forbidden!!one!", Codes.FORBIDDEN)
+
+        res = JsonResource(self.homeserver)
+        res.register_paths("GET", [re.compile("^/foo$")], _callback)
+
+        request, channel = make_request(b"GET", b"/foo")
+        request.render(res)
+
+        self.assertEqual(channel.result["code"], b'403')
+        reply_body = json.loads(channel.result["body"])
+        self.assertEqual(reply_body["error"], "Forbidden!!one!")
+        self.assertEqual(reply_body["errcode"], "M_FORBIDDEN")
+
+    def test_no_handler(self):
+        """
+        If there is no handler to process the request, Synapse will return 400.
+        """
+
+        def _callback(request, **kwargs):
+            """
+            Not ever actually called!
+            """
+            self.fail("shouldn't ever get here")
+
+        res = JsonResource(self.homeserver)
+        res.register_paths("GET", [re.compile("^/foo$")], _callback)
+
+        request, channel = make_request(b"GET", b"/foobar")
+        request.render(res)
+
+        self.assertEqual(channel.result["code"], b'400')
+        reply_body = json.loads(channel.result["body"])
+        self.assertEqual(reply_body["error"], "Unrecognized request")
+        self.assertEqual(reply_body["errcode"], "M_UNRECOGNIZED")
diff --git a/tests/unittest.py b/tests/unittest.py
index 184fe880f3..b25f2db5d5 100644
--- a/tests/unittest.py
+++ b/tests/unittest.py
@@ -35,7 +35,10 @@ class ToTwistedHandler(logging.Handler):
     def emit(self, record):
         log_entry = self.format(record)
         log_level = record.levelname.lower().replace('warning', 'warn')
-        self.tx_log.emit(twisted.logger.LogLevel.levelWithName(log_level), log_entry)
+        self.tx_log.emit(
+            twisted.logger.LogLevel.levelWithName(log_level),
+            log_entry.replace("{", r"(").replace("}", r")"),
+        )
 
 
 handler = ToTwistedHandler()
diff --git a/tests/util/caches/test_descriptors.py b/tests/util/caches/test_descriptors.py
index 24754591df..a94d566c96 100644
--- a/tests/util/caches/test_descriptors.py
+++ b/tests/util/caches/test_descriptors.py
@@ -19,13 +19,19 @@ import logging
 import mock
 from synapse.api.errors import SynapseError
 from synapse.util import logcontext
-from twisted.internet import defer
+from twisted.internet import defer, reactor
 from synapse.util.caches import descriptors
 from tests import unittest
 
 logger = logging.getLogger(__name__)
 
 
+def run_on_reactor():
+    d = defer.Deferred()
+    reactor.callLater(0, d.callback, 0)
+    return logcontext.make_deferred_yieldable(d)
+
+
 class CacheTestCase(unittest.TestCase):
     def test_invalidate_all(self):
         cache = descriptors.Cache("testcache")
@@ -194,6 +200,8 @@ class DescriptorTestCase(unittest.TestCase):
             def fn(self, arg1):
                 @defer.inlineCallbacks
                 def inner_fn():
+                    # we want this to behave like an asynchronous function
+                    yield run_on_reactor()
                     raise SynapseError(400, "blah")
 
                 return inner_fn()
@@ -203,7 +211,12 @@ class DescriptorTestCase(unittest.TestCase):
             with logcontext.LoggingContext() as c1:
                 c1.name = "c1"
                 try:
-                    yield obj.fn(1)
+                    d = obj.fn(1)
+                    self.assertEqual(
+                        logcontext.LoggingContext.current_context(),
+                        logcontext.LoggingContext.sentinel,
+                    )
+                    yield d
                     self.fail("No exception thrown")
                 except SynapseError:
                     pass
diff --git a/tox.ini b/tox.ini
index 5d79098d2f..61a20a10cb 100644
--- a/tox.ini
+++ b/tox.ini
@@ -102,3 +102,11 @@ basepython = python2.7
 deps =
     flake8
 commands = /bin/sh -c "flake8 synapse tests {env:PEP8SUFFIX:}"
+
+
+[testenv:check-newsfragment]
+skip_install = True
+deps = towncrier>=18.6.0rc1
+commands =
+   python -m towncrier.check --compare-with=origin/develop
+basepython = python3.6
\ No newline at end of file