diff --git a/changelog.d/5128.bugfix b/changelog.d/5128.bugfix
new file mode 100644
index 0000000000..46df1e9fd5
--- /dev/null
+++ b/changelog.d/5128.bugfix
@@ -0,0 +1 @@
+Add some missing limitations to room alias creation.
diff --git a/synapse/api/constants.py b/synapse/api/constants.py
index 0860b75905..8547a63535 100644
--- a/synapse/api/constants.py
+++ b/synapse/api/constants.py
@@ -20,6 +20,9 @@
# the "depth" field on events is limited to 2**63 - 1
MAX_DEPTH = 2**63 - 1
+# the maximum length for a room alias is 255 characters
+MAX_ALIAS_LENGTH = 255
+
class Membership(object):
diff --git a/synapse/events/snapshot.py b/synapse/events/snapshot.py
index 368b5f6ae4..fa09c132a0 100644
--- a/synapse/events/snapshot.py
+++ b/synapse/events/snapshot.py
@@ -187,7 +187,9 @@ class EventContext(object):
Returns:
Deferred[dict[(str, str), str]|None]: Returns None if state_group
- is None, which happens when the associated event is an outlier.
+ is None, which happens when the associated event is an outlier.
+ Maps a (type, state_key) to the event ID of the state event matching
+ this tuple.
"""
if not self._fetching_state_deferred:
@@ -205,7 +207,9 @@ class EventContext(object):
Returns:
Deferred[dict[(str, str), str]|None]: Returns None if state_group
- is None, which happens when the associated event is an outlier.
+ is None, which happens when the associated event is an outlier.
+ Maps a (type, state_key) to the event ID of the state event matching
+ this tuple.
"""
if not self._fetching_state_deferred:
diff --git a/synapse/events/validator.py b/synapse/events/validator.py
index 514273c792..711af512b2 100644
--- a/synapse/events/validator.py
+++ b/synapse/events/validator.py
@@ -15,8 +15,8 @@
from six import string_types
-from synapse.api.constants import EventTypes, Membership
-from synapse.api.errors import SynapseError
+from synapse.api.constants import MAX_ALIAS_LENGTH, EventTypes, Membership
+from synapse.api.errors import Codes, SynapseError
from synapse.api.room_versions import EventFormatVersions
from synapse.types import EventID, RoomID, UserID
@@ -56,6 +56,17 @@ class EventValidator(object):
if not isinstance(getattr(event, s), string_types):
raise SynapseError(400, "'%s' not a string type" % (s,))
+ if event.type == EventTypes.Aliases:
+ if "aliases" in event.content:
+ for alias in event.content["aliases"]:
+ if len(alias) > MAX_ALIAS_LENGTH:
+ raise SynapseError(
+ 400,
+ ("Can't create aliases longer than"
+ " %d characters" % (MAX_ALIAS_LENGTH,)),
+ Codes.INVALID_PARAM,
+ )
+
def validate_builder(self, event):
"""Validates that the builder/event has roughly the right format. Only
checks values that we expect a proto event to have, rather than all the
diff --git a/synapse/handlers/directory.py b/synapse/handlers/directory.py
index 50c587aa61..a12f9508d8 100644
--- a/synapse/handlers/directory.py
+++ b/synapse/handlers/directory.py
@@ -19,7 +19,7 @@ import string
from twisted.internet import defer
-from synapse.api.constants import EventTypes
+from synapse.api.constants import MAX_ALIAS_LENGTH, EventTypes
from synapse.api.errors import (
AuthError,
CodeMessageException,
@@ -36,7 +36,6 @@ logger = logging.getLogger(__name__)
class DirectoryHandler(BaseHandler):
- MAX_ALIAS_LENGTH = 255
def __init__(self, hs):
super(DirectoryHandler, self).__init__(hs)
@@ -105,10 +104,10 @@ class DirectoryHandler(BaseHandler):
user_id = requester.user.to_string()
- if len(room_alias.to_string()) > self.MAX_ALIAS_LENGTH:
+ if len(room_alias.to_string()) > MAX_ALIAS_LENGTH:
raise SynapseError(
400,
- "Can't create aliases longer than %s characters" % self.MAX_ALIAS_LENGTH,
+ "Can't create aliases longer than %s characters" % MAX_ALIAS_LENGTH,
Codes.INVALID_PARAM,
)
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 224d34ef3a..e5afeadf68 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -228,6 +228,7 @@ class EventCreationHandler(object):
self.ratelimiter = hs.get_ratelimiter()
self.notifier = hs.get_notifier()
self.config = hs.config
+ self.require_membership_for_aliases = hs.config.require_membership_for_aliases
self.send_event_to_master = ReplicationSendEventRestServlet.make_client(hs)
@@ -336,6 +337,35 @@ class EventCreationHandler(object):
prev_events_and_hashes=prev_events_and_hashes,
)
+ # In an ideal world we wouldn't need the second part of this condition. However,
+ # this behaviour isn't spec'd yet, meaning we should be able to deactivate this
+ # behaviour. Another reason is that this code is also evaluated each time a new
+ # m.room.aliases event is created, which includes hitting a /directory route.
+ # Therefore not including this condition here would render the similar one in
+ # synapse.handlers.directory pointless.
+ if builder.type == EventTypes.Aliases and self.require_membership_for_aliases:
+ # Ideally we'd do the membership check in event_auth.check(), which
+ # describes a spec'd algorithm for authenticating events received over
+ # federation as well as those created locally. As of room v3, aliases events
+ # can be created by users that are not in the room, therefore we have to
+ # tolerate them in event_auth.check().
+ prev_state_ids = yield context.get_prev_state_ids(self.store)
+ prev_event_id = prev_state_ids.get((EventTypes.Member, event.sender))
+ prev_event = yield self.store.get_event(prev_event_id, allow_none=True)
+ if not prev_event or prev_event.membership != Membership.JOIN:
+ logger.warning(
+ ("Attempt to send `m.room.aliases` in room %s by user %s but"
+ " membership is %s"),
+ event.room_id,
+ event.sender,
+ prev_event.membership if prev_event else None,
+ )
+
+ raise AuthError(
+ 403,
+ "You must be in the room to create an alias for it",
+ )
+
self.validator.validate_new(event)
defer.returnValue((event, context))
diff --git a/tests/rest/client/v1/test_directory.py b/tests/rest/client/v1/test_directory.py
new file mode 100644
index 0000000000..4804000ec7
--- /dev/null
+++ b/tests/rest/client/v1/test_directory.py
@@ -0,0 +1,169 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 New Vector Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# 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 json
+
+from synapse.rest.admin import register_servlets
+from synapse.rest.client.v1 import directory, login, room
+from synapse.types import RoomAlias
+from synapse.util.stringutils import random_string
+
+from tests import unittest
+
+
+class DirectoryTestCase(unittest.HomeserverTestCase):
+
+ servlets = [
+ register_servlets,
+ directory.register_servlets,
+ login.register_servlets,
+ room.register_servlets,
+ ]
+
+ def make_homeserver(self, reactor, clock):
+ config = self.default_config()
+ config.require_membership_for_aliases = True
+
+ self.hs = self.setup_test_homeserver(config=config)
+
+ return self.hs
+
+ def prepare(self, reactor, clock, homeserver):
+ self.room_owner = self.register_user("room_owner", "test")
+ self.room_owner_tok = self.login("room_owner", "test")
+
+ self.room_id = self.helper.create_room_as(
+ self.room_owner, tok=self.room_owner_tok,
+ )
+
+ self.user = self.register_user("user", "test")
+ self.user_tok = self.login("user", "test")
+
+ def test_state_event_not_in_room(self):
+ self.ensure_user_left_room()
+ self.set_alias_via_state_event(403)
+
+ def test_directory_endpoint_not_in_room(self):
+ self.ensure_user_left_room()
+ self.set_alias_via_directory(403)
+
+ def test_state_event_in_room_too_long(self):
+ self.ensure_user_joined_room()
+ self.set_alias_via_state_event(400, alias_length=256)
+
+ def test_directory_in_room_too_long(self):
+ self.ensure_user_joined_room()
+ self.set_alias_via_directory(400, alias_length=256)
+
+ def test_state_event_in_room(self):
+ self.ensure_user_joined_room()
+ self.set_alias_via_state_event(200)
+
+ def test_directory_in_room(self):
+ self.ensure_user_joined_room()
+ self.set_alias_via_directory(200)
+
+ def test_room_creation_too_long(self):
+ url = "/_matrix/client/r0/createRoom"
+
+ # We use deliberately a localpart under the length threshold so
+ # that we can make sure that the check is done on the whole alias.
+ data = {
+ "room_alias_name": random_string(256 - len(self.hs.hostname)),
+ }
+ request_data = json.dumps(data)
+ request, channel = self.make_request(
+ "POST", url, request_data, access_token=self.user_tok,
+ )
+ self.render(request)
+ self.assertEqual(channel.code, 400, channel.result)
+
+ def test_room_creation(self):
+ url = "/_matrix/client/r0/createRoom"
+
+ # Check with an alias of allowed length. There should already be
+ # a test that ensures it works in test_register.py, but let's be
+ # as cautious as possible here.
+ data = {
+ "room_alias_name": random_string(5),
+ }
+ request_data = json.dumps(data)
+ request, channel = self.make_request(
+ "POST", url, request_data, access_token=self.user_tok,
+ )
+ self.render(request)
+ self.assertEqual(channel.code, 200, channel.result)
+
+ def set_alias_via_state_event(self, expected_code, alias_length=5):
+ url = ("/_matrix/client/r0/rooms/%s/state/m.room.aliases/%s"
+ % (self.room_id, self.hs.hostname))
+
+ data = {
+ "aliases": [
+ self.random_alias(alias_length),
+ ],
+ }
+ request_data = json.dumps(data)
+
+ request, channel = self.make_request(
+ "PUT", url, request_data, access_token=self.user_tok,
+ )
+ self.render(request)
+ self.assertEqual(channel.code, expected_code, channel.result)
+
+ def set_alias_via_directory(self, expected_code, alias_length=5):
+ url = "/_matrix/client/r0/directory/room/%s" % self.random_alias(alias_length)
+ data = {
+ "room_id": self.room_id,
+ }
+ request_data = json.dumps(data)
+
+ request, channel = self.make_request(
+ "PUT", url, request_data, access_token=self.user_tok,
+ )
+ self.render(request)
+ self.assertEqual(channel.code, expected_code, channel.result)
+
+ def random_alias(self, length):
+ return RoomAlias(
+ random_string(length),
+ self.hs.hostname,
+ ).to_string()
+
+ def ensure_user_left_room(self):
+ self.ensure_membership("leave")
+
+ def ensure_user_joined_room(self):
+ self.ensure_membership("join")
+
+ def ensure_membership(self, membership):
+ try:
+ if membership == "leave":
+ self.helper.leave(
+ room=self.room_id,
+ user=self.user,
+ tok=self.user_tok,
+ )
+ if membership == "join":
+ self.helper.join(
+ room=self.room_id,
+ user=self.user,
+ tok=self.user_tok,
+ )
+ except AssertionError:
+ # We don't care whether the leave request didn't return a 200 (e.g.
+ # if the user isn't already in the room), because we only want to
+ # make sure the user isn't in the room.
+ pass
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