diff --git a/changelog.d/5128.bugfix b/changelog.d/5128.bugfix new file mode 100644 index 000000000..46df1e9fd --- /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 0860b7590..8547a6353 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 368b5f6ae..fa09c132a 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 514273c79..711af512b 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 50c587aa6..a12f9508d 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 224d34ef3..e5afeadf6 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 000000000..4804000ec --- /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