From f3ef60662fd32672f980e3c6e31aa1b25e8ed808 Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <richard@matrix.org>
Date: Mon, 9 Apr 2018 12:56:22 +0100
Subject: Return a 404 rather than a 500 on rejoining empty rooms

Filter ourselves out of the server list before checking for an empty remote
host list, to fix 500 error

Fixes #2141
---
 synapse/handlers/room_member.py | 8 ++++++++
 1 file changed, 8 insertions(+)

(limited to 'synapse/handlers/room_member.py')

diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index 9977be8831..c45142d38d 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -852,6 +852,14 @@ class RoomMemberMasterHandler(RoomMemberHandler):
     def _remote_join(self, requester, remote_room_hosts, room_id, user, content):
         """Implements RoomMemberHandler._remote_join
         """
+        # filter ourselves out of remote_room_hosts: do_invite_join ignores it
+        # and if it is the only entry we'd like to return a 404 rather than a
+        # 500.
+
+        remote_room_hosts = [
+            host for host in remote_room_hosts if host != self.hs.hostname
+        ]
+
         if len(remote_room_hosts) == 0:
             raise SynapseError(404, "No known servers")
 
-- 
cgit 1.4.1


From 639480e14a06723adf6817ddd2b2ff9e4f4cdf2a Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <richard@matrix.org>
Date: Mon, 16 Apr 2018 18:41:37 +0100
Subject: Avoid creating events with huge numbers of prev_events

In most cases, we limit the number of prev_events for a given event to 10
events. This fixes a particular code path which created events with huge
numbers of prev_events.
---
 synapse/handlers/message.py            | 78 +++++++++++++++++++---------------
 synapse/handlers/room_member.py        | 13 ++++--
 synapse/storage/event_federation.py    | 57 ++++++++++++++++++-------
 tests/storage/test_event_federation.py | 68 +++++++++++++++++++++++++++++
 4 files changed, 162 insertions(+), 54 deletions(-)
 create mode 100644 tests/storage/test_event_federation.py

(limited to 'synapse/handlers/room_member.py')

diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 54cd691f91..21628a8540 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -37,7 +37,6 @@ from ._base import BaseHandler
 from canonicaljson import encode_canonical_json
 
 import logging
-import random
 import simplejson
 
 logger = logging.getLogger(__name__)
@@ -433,7 +432,7 @@ class EventCreationHandler(object):
 
     @defer.inlineCallbacks
     def create_event(self, requester, event_dict, token_id=None, txn_id=None,
-                     prev_event_ids=None):
+                     prev_events_and_hashes=None):
         """
         Given a dict from a client, create a new event.
 
@@ -447,7 +446,13 @@ class EventCreationHandler(object):
             event_dict (dict): An entire event
             token_id (str)
             txn_id (str)
-            prev_event_ids (list): The prev event ids to use when creating the event
+
+            prev_events_and_hashes (list[(str, dict[str, str], int)]|None):
+                the forward extremities to use as the prev_events for the
+                new event. For each event, a tuple of (event_id, hashes, depth)
+                where *hashes* is a map from algorithm to hash.
+
+                If None, they will be requested from the database.
 
         Returns:
             Tuple of created event (FrozenEvent), Context
@@ -485,7 +490,7 @@ class EventCreationHandler(object):
         event, context = yield self.create_new_client_event(
             builder=builder,
             requester=requester,
-            prev_event_ids=prev_event_ids,
+            prev_events_and_hashes=prev_events_and_hashes,
         )
 
         defer.returnValue((event, context))
@@ -588,39 +593,44 @@ class EventCreationHandler(object):
 
     @measure_func("create_new_client_event")
     @defer.inlineCallbacks
-    def create_new_client_event(self, builder, requester=None, prev_event_ids=None):
-        if prev_event_ids:
-            prev_events = yield self.store.add_event_hashes(prev_event_ids)
-            prev_max_depth = yield self.store.get_max_depth_of_events(prev_event_ids)
-            depth = prev_max_depth + 1
-        else:
-            latest_ret = yield self.store.get_latest_event_ids_and_hashes_in_room(
-                builder.room_id,
+    def create_new_client_event(self, builder, requester=None,
+                                prev_events_and_hashes=None):
+        """Create a new event for a local client
+
+        Args:
+            builder (EventBuilder):
+
+            requester (synapse.types.Requester|None):
+
+            prev_events_and_hashes (list[(str, dict[str, str], int)]|None):
+                the forward extremities to use as the prev_events for the
+                new event. For each event, a tuple of (event_id, hashes, depth)
+                where *hashes* is a map from algorithm to hash.
+
+                If None, they will be requested from the database.
+
+        Returns:
+            Deferred[(synapse.events.EventBase, synapse.events.snapshot.EventContext)]
+        """
+
+        if prev_events_and_hashes is not None:
+            assert len(prev_events_and_hashes) <= 10, \
+                "Attempting to create an event with %i prev_events" % (
+                    len(prev_events_and_hashes),
             )
+        else:
+            prev_events_and_hashes = \
+                yield self.store.get_prev_events_for_room(builder.room_id)
 
-            # We want to limit the max number of prev events we point to in our
-            # new event
-            if len(latest_ret) > 10:
-                # Sort by reverse depth, so we point to the most recent.
-                latest_ret.sort(key=lambda a: -a[2])
-                new_latest_ret = latest_ret[:5]
-
-                # We also randomly point to some of the older events, to make
-                # sure that we don't completely ignore the older events.
-                if latest_ret[5:]:
-                    sample_size = min(5, len(latest_ret[5:]))
-                    new_latest_ret.extend(random.sample(latest_ret[5:], sample_size))
-                latest_ret = new_latest_ret
-
-            if latest_ret:
-                depth = max([d for _, _, d in latest_ret]) + 1
-            else:
-                depth = 1
+        if prev_events_and_hashes:
+            depth = max([d for _, _, d in prev_events_and_hashes]) + 1
+        else:
+            depth = 1
 
-            prev_events = [
-                (event_id, prev_hashes)
-                for event_id, prev_hashes, _ in latest_ret
-            ]
+        prev_events = [
+            (event_id, prev_hashes)
+            for event_id, prev_hashes, _ in prev_events_and_hashes
+        ]
 
         builder.prev_events = prev_events
         builder.depth = depth
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index c45142d38d..714583f1d5 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -149,7 +149,7 @@ class RoomMemberHandler(object):
     @defer.inlineCallbacks
     def _local_membership_update(
         self, requester, target, room_id, membership,
-        prev_event_ids,
+        prev_events_and_hashes,
         txn_id=None,
         ratelimit=True,
         content=None,
@@ -175,7 +175,7 @@ class RoomMemberHandler(object):
             },
             token_id=requester.access_token_id,
             txn_id=txn_id,
-            prev_event_ids=prev_event_ids,
+            prev_events_and_hashes=prev_events_and_hashes,
         )
 
         # Check if this event matches the previous membership event for the user.
@@ -314,7 +314,12 @@ class RoomMemberHandler(object):
                     403, "Invites have been disabled on this server",
                 )
 
-        latest_event_ids = yield self.store.get_latest_event_ids_in_room(room_id)
+        prev_events_and_hashes = yield self.store.get_prev_events_for_room(
+            room_id,
+        )
+        latest_event_ids = (
+            event_id for (event_id, _, _) in prev_events_and_hashes
+        )
         current_state_ids = yield self.state_handler.get_current_state_ids(
             room_id, latest_event_ids=latest_event_ids,
         )
@@ -403,7 +408,7 @@ class RoomMemberHandler(object):
             membership=effective_membership_state,
             txn_id=txn_id,
             ratelimit=ratelimit,
-            prev_event_ids=latest_event_ids,
+            prev_events_and_hashes=prev_events_and_hashes,
             content=content,
         )
         defer.returnValue(res)
diff --git a/synapse/storage/event_federation.py b/synapse/storage/event_federation.py
index 00ee82d300..a183fc6b50 100644
--- a/synapse/storage/event_federation.py
+++ b/synapse/storage/event_federation.py
@@ -12,6 +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.
+import random
 
 from twisted.internet import defer
 
@@ -133,7 +134,47 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore,
             retcol="event_id",
         )
 
+    @defer.inlineCallbacks
+    def get_prev_events_for_room(self, room_id):
+        """
+        Gets a subset of the current forward extremities in the given room.
+
+        Limits the result to 10 extremities, so that we can avoid creating
+        events which refer to hundreds of prev_events.
+
+        Args:
+            room_id (str): room_id
+
+        Returns:
+            Deferred[list[(str, dict[str, str], int)]]
+                for each event, a tuple of (event_id, hashes, depth)
+                where *hashes* is a map from algorithm to hash.
+        """
+        res = yield self.get_latest_event_ids_and_hashes_in_room(room_id)
+        if len(res) > 10:
+            # Sort by reverse depth, so we point to the most recent.
+            res.sort(key=lambda a: -a[2])
+
+            # we use half of the limit for the actual most recent events, and
+            # the other half to randomly point to some of the older events, to
+            # make sure that we don't completely ignore the older events.
+            res = res[0:5] + random.sample(res[5:], 5)
+
+        defer.returnValue(res)
+
     def get_latest_event_ids_and_hashes_in_room(self, room_id):
+        """
+        Gets the current forward extremities in the given room
+
+        Args:
+            room_id (str): room_id
+
+        Returns:
+            Deferred[list[(str, dict[str, str], int)]]
+                for each event, a tuple of (event_id, hashes, depth)
+                where *hashes* is a map from algorithm to hash.
+        """
+
         return self.runInteraction(
             "get_latest_event_ids_and_hashes_in_room",
             self._get_latest_event_ids_and_hashes_in_room,
@@ -182,22 +223,6 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore,
             room_id,
         )
 
-    @defer.inlineCallbacks
-    def get_max_depth_of_events(self, event_ids):
-        sql = (
-            "SELECT MAX(depth) FROM events WHERE event_id IN (%s)"
-        ) % (",".join(["?"] * len(event_ids)),)
-
-        rows = yield self._execute(
-            "get_max_depth_of_events", None,
-            sql, *event_ids
-        )
-
-        if rows:
-            defer.returnValue(rows[0][0])
-        else:
-            defer.returnValue(1)
-
     def _get_min_depth_interaction(self, txn, room_id):
         min_depth = self._simple_select_one_onecol_txn(
             txn,
diff --git a/tests/storage/test_event_federation.py b/tests/storage/test_event_federation.py
new file mode 100644
index 0000000000..30683e7888
--- /dev/null
+++ b/tests/storage/test_event_federation.py
@@ -0,0 +1,68 @@
+# -*- 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 twisted.internet import defer
+
+import tests.unittest
+import tests.utils
+
+
+class EventFederationWorkerStoreTestCase(tests.unittest.TestCase):
+    @defer.inlineCallbacks
+    def setUp(self):
+        hs = yield tests.utils.setup_test_homeserver()
+        self.store = hs.get_datastore()
+
+    @defer.inlineCallbacks
+    def test_get_prev_events_for_room(self):
+        room_id = '@ROOM:local'
+
+        # add a bunch of events and hashes to act as forward extremities
+        def insert_event(txn, i):
+            event_id = '$event_%i:local' % i
+
+            txn.execute((
+                "INSERT INTO events ("
+                "   room_id, event_id, type, depth, topological_ordering,"
+                "   content, processed, outlier) "
+                "VALUES (?, ?, 'm.test', ?, ?, 'test', ?, ?)"
+            ), (room_id, event_id, i, i, True, False))
+
+            txn.execute((
+                'INSERT INTO event_forward_extremities (room_id, event_id) '
+                'VALUES (?, ?)'
+            ), (room_id, event_id))
+
+            txn.execute((
+                'INSERT INTO event_reference_hashes '
+                '(event_id, algorithm, hash) '
+                "VALUES (?, 'sha256', ?)"
+            ), (event_id, 'ffff'))
+
+        for i in range(0, 11):
+            yield self.store.runInteraction("insert", insert_event, i)
+
+        # this should get the last five and five others
+        r = yield self.store.get_prev_events_for_room(room_id)
+        self.assertEqual(10, len(r))
+        for i in range(0, 5):
+            el = r[i]
+            depth = el[2]
+            self.assertEqual(10 - i, depth)
+
+        for i in range(5, 5):
+            el = r[i]
+            depth = el[2]
+            self.assertLessEqual(5, depth)
-- 
cgit 1.4.1


From fed62e21ad2c0f622ed47283b41064e9fecaa00b Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <richard@matrix.org>
Date: Thu, 17 May 2018 11:34:28 +0100
Subject: Infrastructure for a server notices room

Server Notices use a special room which the user can't dismiss. They are
created on demand when some other bit of the code calls send_notice.

(This doesn't actually do much yet becuse we don't call send_notice anywhere)
---
 synapse/config/homeserver.py                     |   5 +-
 synapse/config/server_notices_config.py          |  85 ++++++++++++++++++
 synapse/handlers/register.py                     |  14 +++
 synapse/handlers/room.py                         |  16 +++-
 synapse/handlers/room_member.py                  |  40 ++++++++-
 synapse/server.py                                |   5 ++
 synapse/server.pyi                               |  12 +++
 synapse/server_notices/__init__.py               |   0
 synapse/server_notices/server_notices_manager.py | 110 +++++++++++++++++++++++
 9 files changed, 280 insertions(+), 7 deletions(-)
 create mode 100644 synapse/config/server_notices_config.py
 create mode 100644 synapse/server_notices/__init__.py
 create mode 100644 synapse/server_notices/server_notices_manager.py

(limited to 'synapse/handlers/room_member.py')

diff --git a/synapse/config/homeserver.py b/synapse/config/homeserver.py
index fb6bd3b421..1dea2ad024 100644
--- a/synapse/config/homeserver.py
+++ b/synapse/config/homeserver.py
@@ -38,6 +38,7 @@ from .spam_checker import SpamCheckerConfig
 from .groups import GroupsConfig
 from .user_directory import UserDirectoryConfig
 from .consent_config import ConsentConfig
+from .server_notices_config import ServerNoticesConfig
 
 
 class HomeServerConfig(TlsConfig, ServerConfig, DatabaseConfig, LoggingConfig,
@@ -47,7 +48,9 @@ class HomeServerConfig(TlsConfig, ServerConfig, DatabaseConfig, LoggingConfig,
                        JWTConfig, PasswordConfig, EmailConfig,
                        WorkerConfig, PasswordAuthProviderConfig, PushConfig,
                        SpamCheckerConfig, GroupsConfig, UserDirectoryConfig,
-                       ConsentConfig):
+                       ConsentConfig,
+                       ServerNoticesConfig,
+                       ):
     pass
 
 
diff --git a/synapse/config/server_notices_config.py b/synapse/config/server_notices_config.py
new file mode 100644
index 0000000000..51ddcac112
--- /dev/null
+++ b/synapse/config/server_notices_config.py
@@ -0,0 +1,85 @@
+# -*- 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 ._base import Config
+from synapse.types import UserID
+
+DEFAULT_CONFIG = """\
+# Server Notices room configuration
+#
+# Uncomment this section to enable a room which can be used to send notices
+# from the server to users. It is a special room which cannot be left; notices
+# come from a special "notices" user id.
+#
+# If you uncomment this section, you *must* define the system_mxid_localpart
+# setting, which defines the id of the user which will be used to send the
+# notices.
+#
+# It's also possible to override the room name, or the display name of the
+# "notices" user.
+#
+# server_notices:
+#   system_mxid_localpart: notices
+#   system_mxid_display_name: "Server Notices"
+#   room_name: "Server Notices"
+"""
+
+
+class ServerNoticesConfig(Config):
+    def __init__(self):
+        super(ServerNoticesConfig, self).__init__()
+
+        """The MXID to use for server notices.
+
+        None if server notices are not enabled.
+
+        type: str|None
+        """
+        self.server_notices_mxid = None
+
+        """The display name to use for the server notices user.
+
+        None if server notices are not enabled.
+
+        type: str|None
+        """
+        self.server_notices_mxid_display_name = None
+
+        """The name to use for the server notices room.
+
+        None if server notices are not enabled.
+
+        (TODO: i18n)
+
+        type: str|None
+        """
+        self.server_notices_room_name = None
+
+    def read_config(self, config):
+        c = config.get("server_notices")
+        if c is None:
+            return
+
+        mxid_localpart = c['system_mxid_localpart']
+        self.server_notices_mxid = UserID(
+            mxid_localpart, self.server_name,
+        ).to_string()
+        self.server_notices_mxid_display_name = c.get(
+            'system_mxid_display_name', 'Server Notices',
+        )
+
+        self.server_notices_room_name = c.get('room_name', "Server Notices")
+
+    def default_config(self, **kwargs):
+        return DEFAULT_CONFIG
diff --git a/synapse/handlers/register.py b/synapse/handlers/register.py
index f83c6b3cf8..7e52adda3c 100644
--- a/synapse/handlers/register.py
+++ b/synapse/handlers/register.py
@@ -34,6 +34,11 @@ logger = logging.getLogger(__name__)
 class RegistrationHandler(BaseHandler):
 
     def __init__(self, hs):
+        """
+
+        Args:
+            hs (synapse.server.HomeServer):
+        """
         super(RegistrationHandler, self).__init__(hs)
 
         self.auth = hs.get_auth()
@@ -49,6 +54,7 @@ class RegistrationHandler(BaseHandler):
         self._generate_user_id_linearizer = Linearizer(
             name="_generate_user_id_linearizer",
         )
+        self._server_notices_mxid = hs.config.server_notices_mxid
 
     @defer.inlineCallbacks
     def check_username(self, localpart, guest_access_token=None,
@@ -338,6 +344,14 @@ class RegistrationHandler(BaseHandler):
             yield identity_handler.bind_threepid(c, user_id)
 
     def check_user_id_not_appservice_exclusive(self, user_id, allowed_appservice=None):
+        # don't allow people to register the server notices mxid
+        if self._server_notices_mxid is not None:
+            if user_id == self._server_notices_mxid:
+                raise SynapseError(
+                    400, "This user ID is reserved.",
+                    errcode=Codes.EXCLUSIVE
+                )
+
         # valid user IDs must not clash with any user ID namespaces claimed by
         # application services.
         services = self.store.get_app_services()
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index e36426de5a..5e9fa95a2d 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -68,7 +68,8 @@ class RoomCreationHandler(BaseHandler):
         self.event_creation_handler = hs.get_event_creation_handler()
 
     @defer.inlineCallbacks
-    def create_room(self, requester, config, ratelimit=True):
+    def create_room(self, requester, config, ratelimit=True,
+                    creator_join_profile=None):
         """ Creates a new room.
 
         Args:
@@ -76,6 +77,14 @@ class RoomCreationHandler(BaseHandler):
                 The user who requested the room creation.
             config (dict) : A dict of configuration options.
             ratelimit (bool): set to False to disable the rate limiter
+
+            creator_join_profile (dict|None):
+                Set to override the displayname and avatar for the creating
+                user in this room. If unset, displayname and avatar will be
+                derived from the user's profile. If set, should contain the
+                values to go in the body of the 'join' event (typically
+                `avatar_url` and/or `displayname`.
+
         Returns:
             Deferred[dict]:
                 a dict containing the keys `room_id` and, if an alias was
@@ -180,7 +189,8 @@ class RoomCreationHandler(BaseHandler):
             initial_state=initial_state,
             creation_content=creation_content,
             room_alias=room_alias,
-            power_level_content_override=config.get("power_level_content_override", {})
+            power_level_content_override=config.get("power_level_content_override", {}),
+            creator_join_profile=creator_join_profile,
         )
 
         if "name" in config:
@@ -260,6 +270,7 @@ class RoomCreationHandler(BaseHandler):
             creation_content,
             room_alias,
             power_level_content_override,
+            creator_join_profile,
     ):
         def create(etype, content, **kwargs):
             e = {
@@ -303,6 +314,7 @@ class RoomCreationHandler(BaseHandler):
             room_id,
             "join",
             ratelimit=False,
+            content=creator_join_profile,
         )
 
         # We treat the power levels override specially as this needs to be one
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index 714583f1d5..9f8975e1f2 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -17,11 +17,14 @@
 import abc
 import logging
 
+from six.moves import http_client
+
 from signedjson.key import decode_verify_key_bytes
 from signedjson.sign import verify_signed_json
 from twisted.internet import defer
 from unpaddedbase64 import decode_base64
 
+import synapse.server
 import synapse.types
 from synapse.api.constants import (
     EventTypes, Membership,
@@ -46,6 +49,11 @@ class RoomMemberHandler(object):
     __metaclass__ = abc.ABCMeta
 
     def __init__(self, hs):
+        """
+
+        Args:
+            hs (synapse.server.HomeServer):
+        """
         self.hs = hs
         self.store = hs.get_datastore()
         self.auth = hs.get_auth()
@@ -63,6 +71,7 @@ class RoomMemberHandler(object):
 
         self.clock = hs.get_clock()
         self.spam_checker = hs.get_spam_checker()
+        self._server_notices_mxid = self.config.server_notices_mxid
 
     @abc.abstractmethod
     def _remote_join(self, requester, remote_room_hosts, room_id, user, content):
@@ -289,12 +298,28 @@ class RoomMemberHandler(object):
             is_blocked = yield self.store.is_room_blocked(room_id)
             if is_blocked:
                 raise SynapseError(403, "This room has been blocked on this server")
+        else:
+            if self._is_server_notice_room(room_id):
+                # we don't allow people to reject invites to, or leave, the
+                # server notice room.
+                raise SynapseError(
+                    http_client.FORBIDDEN,
+                    "You cannot leave this room",
+                )
 
-        if effective_membership_state == "invite":
+        if effective_membership_state == Membership.INVITE:
             block_invite = False
-            is_requester_admin = yield self.auth.is_server_admin(
-                requester.user,
-            )
+
+            if (self._server_notices_mxid is not None and
+                    requester.user.to_string() == self._server_notices_mxid):
+                # allow the server notices mxid to send invites
+                is_requester_admin = True
+
+            else:
+                is_requester_admin = yield self.auth.is_server_admin(
+                    requester.user,
+                )
+
             if not is_requester_admin:
                 if self.config.block_non_admin_invites:
                     logger.info(
@@ -844,6 +869,13 @@ class RoomMemberHandler(object):
 
         defer.returnValue(False)
 
+    @defer.inlineCallbacks
+    def _is_server_notice_room(self, room_id):
+        if self._server_notices_mxid is None:
+            defer.returnValue(False)
+        user_ids = yield self.store.get_users_in_room(room_id)
+        defer.returnValue(self._server_notices_mxid in user_ids)
+
 
 class RoomMemberMasterHandler(RoomMemberHandler):
     def __init__(self, hs):
diff --git a/synapse/server.py b/synapse/server.py
index 9e6f3584b2..85f54cd047 100644
--- a/synapse/server.py
+++ b/synapse/server.py
@@ -72,6 +72,7 @@ from synapse.rest.media.v1.media_repository import (
     MediaRepository,
     MediaRepositoryResource,
 )
+from synapse.server_notices.server_notices_manager import ServerNoticesManager
 from synapse.state import StateHandler, StateResolutionHandler
 from synapse.storage import DataStore
 from synapse.streams.events import EventSources
@@ -156,6 +157,7 @@ class HomeServer(object):
         'spam_checker',
         'room_member_handler',
         'federation_registry',
+        'server_notices_manager',
     ]
 
     def __init__(self, hostname, **kwargs):
@@ -398,6 +400,9 @@ class HomeServer(object):
     def build_federation_registry(self):
         return FederationHandlerRegistry()
 
+    def build_server_notices_manager(self):
+        return ServerNoticesManager(self)
+
     def remove_pusher(self, app_id, push_key, user_id):
         return self.get_pusherpool().remove_pusher(app_id, push_key, user_id)
 
diff --git a/synapse/server.pyi b/synapse/server.pyi
index aeda093f27..6fbe15168d 100644
--- a/synapse/server.pyi
+++ b/synapse/server.pyi
@@ -1,4 +1,5 @@
 import synapse.api.auth
+import synapse.config.homeserver
 import synapse.federation.transaction_queue
 import synapse.federation.transport.client
 import synapse.handlers
@@ -8,11 +9,16 @@ import synapse.handlers.device
 import synapse.handlers.e2e_keys
 import synapse.handlers.set_password
 import synapse.rest.media.v1.media_repository
+import synapse.server_notices.server_notices_manager
 import synapse.state
 import synapse.storage
 
 
 class HomeServer(object):
+    @property
+    def config(self) -> synapse.config.homeserver.HomeServerConfig:
+        pass
+
     def get_auth(self) -> synapse.api.auth.Auth:
         pass
 
@@ -43,6 +49,9 @@ class HomeServer(object):
     def get_room_creation_handler(self) -> synapse.handlers.room.RoomCreationHandler:
         pass
 
+    def get_event_creation_handler(self) -> synapse.handlers.message.EventCreationHandler:
+        pass
+
     def get_set_password_handler(self) -> synapse.handlers.set_password.SetPasswordHandler:
         pass
 
@@ -57,3 +66,6 @@ class HomeServer(object):
 
     def get_media_repository(self) -> synapse.rest.media.v1.media_repository.MediaRepository:
         pass
+
+    def get_server_notices_manager(self) -> synapse.server_notices.server_notices_manager.ServerNoticesManager:
+        pass
diff --git a/synapse/server_notices/__init__.py b/synapse/server_notices/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/synapse/server_notices/server_notices_manager.py b/synapse/server_notices/server_notices_manager.py
new file mode 100644
index 0000000000..0d48aeb95e
--- /dev/null
+++ b/synapse/server_notices/server_notices_manager.py
@@ -0,0 +1,110 @@
+# -*- 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 twisted.internet import defer
+
+from synapse.api.constants import EventTypes, Membership, RoomCreationPreset
+from synapse.types import create_requester
+from synapse.util.caches.descriptors import cachedInlineCallbacks
+
+logger = logging.getLogger(__name__)
+
+
+class ServerNoticesManager(object):
+    def __init__(self, hs):
+        """
+
+        Args:
+            hs (synapse.server.HomeServer):
+        """
+
+        self._store = hs.get_datastore()
+        self._config = hs.config
+        self._room_creation_handler = hs.get_room_creation_handler()
+        self._event_creation_handler = hs.get_event_creation_handler()
+
+    def is_enabled(self):
+        return self._config.server_notices_mxid is not None
+
+    @defer.inlineCallbacks
+    def send_notice(self, user_id, event_content):
+        room_id = yield self.get_notice_room_for_user(user_id)
+
+        system_mxid = self._config.server_notices_mxid
+        requester = create_requester(system_mxid)
+
+        logger.info("Sending server notice to %s", user_id)
+
+        yield self._event_creation_handler.create_and_send_nonmember_event(
+            requester, {
+                "type": EventTypes.Message,
+                "room_id": room_id,
+                "sender": system_mxid,
+                "content": event_content,
+            },
+            ratelimit=False,
+        )
+
+    @cachedInlineCallbacks()
+    def get_notice_room_for_user(self, user_id):
+        """Get the room for notices for a given user
+
+        If we have not yet created a notice room for this user, create it
+
+        Args:
+            user_id (str): complete user id for the user we want a room for
+
+        Returns:
+            str: room id of notice room.
+        """
+        if not self.is_enabled():
+            raise Exception("Server notices not enabled")
+
+        rooms = yield self._store.get_rooms_for_user_where_membership_is(
+            user_id, [Membership.INVITE, Membership.JOIN],
+        )
+        system_mxid = self._config.server_notices_mxid
+        for room in rooms:
+            user_ids = yield self._store.get_users_in_room(room.room_id)
+            if system_mxid in user_ids:
+                # we found a room which our user shares with the system notice
+                # user
+                logger.info("Using room %s", room.room_id)
+                defer.returnValue(room.room_id)
+
+        # apparently no existing notice room: create a new one
+        logger.info("Creating server notices room for %s", user_id)
+
+        requester = create_requester(system_mxid)
+        info = yield self._room_creation_handler.create_room(
+            requester,
+            config={
+                "preset": RoomCreationPreset.PRIVATE_CHAT,
+                "name": self._config.server_notices_room_name,
+                "power_level_content_override": {
+                    "users_default": -10,
+                },
+                "invite": (user_id,)
+            },
+            ratelimit=False,
+            creator_join_profile={
+                "displayname": self._config.server_notices_mxid_display_name,
+            },
+        )
+        room_id = info['room_id']
+
+        logger.info("Created server notices room %s for %s", room_id, user_id)
+        defer.returnValue(room_id)
-- 
cgit 1.4.1


From 88d34053326328f3ce62d424c72ed0244f1955d4 Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <richard@matrix.org>
Date: Thu, 17 May 2018 18:33:45 +0100
Subject: fix missing yield for server_notices_room

---
 synapse/handlers/room_member.py | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

(limited to 'synapse/handlers/room_member.py')

diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index 9f8975e1f2..9b99f0f9d7 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -299,9 +299,10 @@ class RoomMemberHandler(object):
             if is_blocked:
                 raise SynapseError(403, "This room has been blocked on this server")
         else:
-            if self._is_server_notice_room(room_id):
-                # we don't allow people to reject invites to, or leave, the
-                # server notice room.
+            # we don't allow people to reject invites to, or leave, the
+            # server notice room.
+            is_blocked = yield self._is_server_notice_room(room_id)
+            if is_blocked:
                 raise SynapseError(
                     http_client.FORBIDDEN,
                     "You cannot leave this room",
-- 
cgit 1.4.1


From 26305788fe23448d65d0cd0358df547e816574f2 Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <richard@matrix.org>
Date: Fri, 18 May 2018 11:18:39 +0100
Subject: Make sure we reject attempts to invite the notices user

---
 synapse/handlers/federation.py                   | 8 ++++++++
 synapse/handlers/room_member.py                  | 7 +++++++
 synapse/server_notices/server_notices_manager.py | 5 +++++
 3 files changed, 20 insertions(+)

(limited to 'synapse/handlers/room_member.py')

diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index f39233d846..ba3ede8024 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -81,6 +81,7 @@ class FederationHandler(BaseHandler):
         self.pusher_pool = hs.get_pusherpool()
         self.spam_checker = hs.get_spam_checker()
         self.event_creation_handler = hs.get_event_creation_handler()
+        self._server_notices_mxid = hs.config.server_notices_mxid
 
         # When joining a room we need to queue any events for that room up
         self.room_queues = {}
@@ -1180,6 +1181,13 @@ class FederationHandler(BaseHandler):
         if not self.is_mine_id(event.state_key):
             raise SynapseError(400, "The invite event must be for this server")
 
+        # block any attempts to invite the server notices mxid
+        if event.state_key == self._server_notices_mxid:
+            raise SynapseError(
+                http_client.FORBIDDEN,
+                "Cannot invite this user",
+            )
+
         event.internal_metadata.outlier = True
         event.internal_metadata.invite_from_remote = True
 
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index 9b99f0f9d7..5263f09aaa 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -309,6 +309,13 @@ class RoomMemberHandler(object):
                 )
 
         if effective_membership_state == Membership.INVITE:
+            # block any attempts to invite the server notices mxid
+            if target.to_string() == self._server_notices_mxid:
+                raise SynapseError(
+                    http_client.FORBIDDEN,
+                    "Cannot invite this user",
+                )
+
             block_invite = False
 
             if (self._server_notices_mxid is not None and
diff --git a/synapse/server_notices/server_notices_manager.py b/synapse/server_notices/server_notices_manager.py
index 0d48aeb95e..15086600ed 100644
--- a/synapse/server_notices/server_notices_manager.py
+++ b/synapse/server_notices/server_notices_manager.py
@@ -78,6 +78,11 @@ class ServerNoticesManager(object):
         )
         system_mxid = self._config.server_notices_mxid
         for room in rooms:
+            # it's worth noting that there is an asymmetry here in that we
+            # expect the user to be invited or joined, but the system user must
+            # be joined. This is kinda deliberate, in that if somebody somehow
+            # manages to invite the system user to a room, that doesn't make it
+            # the server notices room.
             user_ids = yield self._store.get_users_in_room(room.room_id)
             if system_mxid in user_ids:
                 # we found a room which our user shares with the system notice
-- 
cgit 1.4.1


From 08bfc48abf8c138b540ede6c816338c044130dec Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <richard@matrix.org>
Date: Tue, 22 May 2018 17:27:03 +0100
Subject: custom error code for not leaving server notices room

---
 synapse/api/errors.py           | 1 +
 synapse/handlers/room_member.py | 1 +
 2 files changed, 2 insertions(+)

(limited to 'synapse/handlers/room_member.py')

diff --git a/synapse/api/errors.py b/synapse/api/errors.py
index aca804280c..e6ad3768f0 100644
--- a/synapse/api/errors.py
+++ b/synapse/api/errors.py
@@ -53,6 +53,7 @@ class Codes(object):
     INVALID_USERNAME = "M_INVALID_USERNAME"
     SERVER_NOT_TRUSTED = "M_SERVER_NOT_TRUSTED"
     CONSENT_NOT_GIVEN = "M_CONSENT_NOT_GIVEN"
+    CANNOT_LEAVE_SERVER_NOTICE_ROOM = "M_CANNOT_LEAVE_SERVER_NOTICE_ROOM"
 
 
 class CodeMessageException(RuntimeError):
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index 5263f09aaa..82adfc8fdf 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -306,6 +306,7 @@ class RoomMemberHandler(object):
                 raise SynapseError(
                     http_client.FORBIDDEN,
                     "You cannot leave this room",
+                    errcode=Codes.CANNOT_LEAVE_SERVER_NOTICE_ROOM,
                 )
 
         if effective_membership_state == Membership.INVITE:
-- 
cgit 1.4.1


From 757ed2725803ff6d190eb1bb8dea872345862aa3 Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <richard@matrix.org>
Date: Fri, 25 May 2018 11:07:21 +0100
Subject: Let users leave the server notice room after joining

They still can't reject invites, but we let them leave it.
---
 docs/server_notices.md          |  7 +++++--
 synapse/handlers/room_member.py | 24 ++++++++++++++----------
 2 files changed, 19 insertions(+), 12 deletions(-)

(limited to 'synapse/handlers/room_member.py')

diff --git a/docs/server_notices.md b/docs/server_notices.md
index 221553b24d..58f8776319 100644
--- a/docs/server_notices.md
+++ b/docs/server_notices.md
@@ -5,7 +5,7 @@ Server Notices
 channel whereby server administrators can send messages to users on the server.
 
 They are used as part of communication of the server polices(see
-[consent_tracking.md](consent_tracking.md)), however the intention is that 
+[consent_tracking.md](consent_tracking.md)), however the intention is that
 they may also find a use for features such as "Message of the day".
 
 This is a feature specific to Synapse, but it uses standard Matrix
@@ -24,7 +24,10 @@ history; it will appear to have come from the 'server notices user' (see
 below).
 
 The user is prevented from sending any messages in this room by the power
-levels. They also cannot leave it.
+levels.
+
+Having joined the room, the user can leave the room if they want. Subsequent
+server notices will then cause a new room to be created.
 
 Synapse configuration
 ---------------------
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index 82adfc8fdf..f930e939e8 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -298,16 +298,6 @@ class RoomMemberHandler(object):
             is_blocked = yield self.store.is_room_blocked(room_id)
             if is_blocked:
                 raise SynapseError(403, "This room has been blocked on this server")
-        else:
-            # we don't allow people to reject invites to, or leave, the
-            # server notice room.
-            is_blocked = yield self._is_server_notice_room(room_id)
-            if is_blocked:
-                raise SynapseError(
-                    http_client.FORBIDDEN,
-                    "You cannot leave this room",
-                    errcode=Codes.CANNOT_LEAVE_SERVER_NOTICE_ROOM,
-                )
 
         if effective_membership_state == Membership.INVITE:
             # block any attempts to invite the server notices mxid
@@ -383,6 +373,20 @@ class RoomMemberHandler(object):
                 if same_sender and same_membership and same_content:
                     defer.returnValue(old_state)
 
+            # we don't allow people to reject invites to the server notice
+            # room, but they can leave it once they are joined.
+            if (
+                old_membership == Membership.INVITE and
+                effective_membership_state == Membership.LEAVE
+            ):
+                is_blocked = yield self._is_server_notice_room(room_id)
+                if is_blocked:
+                    raise SynapseError(
+                        http_client.FORBIDDEN,
+                        "You cannot reject this invite",
+                        errcode=Codes.CANNOT_LEAVE_SERVER_NOTICE_ROOM,
+                    )
+
         is_host_in_room = yield self._is_host_in_room(current_state_ids)
 
         if effective_membership_state == Membership.JOIN:
-- 
cgit 1.4.1