diff --git a/changelog.d/9258.feature b/changelog.d/9258.feature new file mode 100644 index 0000000000..0028f42d26 --- /dev/null +++ b/changelog.d/9258.feature @@ -0,0 +1 @@ +Add ratelimits to invites in rooms and to specific users. diff --git a/docs/sample_config.yaml b/docs/sample_config.yaml index 332befd948..7fd35516dc 100644 --- a/docs/sample_config.yaml +++ b/docs/sample_config.yaml @@ -825,6 +825,8 @@ log_config: "CONFDIR/SERVERNAME.log.config" # "remote" for when users are trying to join rooms not on the server (which # can be more expensive) # - one for ratelimiting how often a user or IP can attempt to validate a 3PID. +# - two for ratelimiting how often invites can be sent in a room or to a +# specific user. # # The defaults are as shown below. # @@ -862,6 +864,14 @@ log_config: "CONFDIR/SERVERNAME.log.config" #rc_3pid_validation: # per_second: 0.003 # burst_count: 5 +# +#rc_invites: +# per_room: +# per_second: 0.3 +# burst_count: 10 +# per_user: +# per_second: 0.003 +# burst_count: 5 # Ratelimiting settings for incoming federation # diff --git a/synapse/config/ratelimiting.py b/synapse/config/ratelimiting.py index 76f382527d..def33a60ad 100644 --- a/synapse/config/ratelimiting.py +++ b/synapse/config/ratelimiting.py @@ -107,6 +107,15 @@ class RatelimitConfig(Config): defaults={"per_second": 0.003, "burst_count": 5}, ) + self.rc_invites_per_room = RateLimitConfig( + config.get("rc_invites", {}).get("per_room", {}), + defaults={"per_second": 0.3, "burst_count": 10}, + ) + self.rc_invites_per_user = RateLimitConfig( + config.get("rc_invites", {}).get("per_user", {}), + defaults={"per_second": 0.003, "burst_count": 5}, + ) + def generate_config_section(self, **kwargs): return """\ ## Ratelimiting ## @@ -137,6 +146,8 @@ class RatelimitConfig(Config): # "remote" for when users are trying to join rooms not on the server (which # can be more expensive) # - one for ratelimiting how often a user or IP can attempt to validate a 3PID. + # - two for ratelimiting how often invites can be sent in a room or to a + # specific user. # # The defaults are as shown below. # @@ -174,6 +185,14 @@ class RatelimitConfig(Config): #rc_3pid_validation: # per_second: 0.003 # burst_count: 5 + # + #rc_invites: + # per_room: + # per_second: 0.3 + # burst_count: 10 + # per_user: + # per_second: 0.003 + # burst_count: 5 # Ratelimiting settings for incoming federation # diff --git a/synapse/federation/federation_client.py b/synapse/federation/federation_client.py index d330ae5dbc..40e1451201 100644 --- a/synapse/federation/federation_client.py +++ b/synapse/federation/federation_client.py @@ -810,7 +810,7 @@ class FederationClient(FederationBase): "User's homeserver does not support this room version", Codes.UNSUPPORTED_ROOM_VERSION, ) - elif e.code == 403: + elif e.code in (403, 429): raise e.to_synapse_error() else: raise diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py index b6dc7f99b6..dbdfd56ff5 100644 --- a/synapse/handlers/federation.py +++ b/synapse/handlers/federation.py @@ -1617,6 +1617,10 @@ class FederationHandler(BaseHandler): if event.state_key == self._server_notices_mxid: raise SynapseError(HTTPStatus.FORBIDDEN, "Cannot invite this user") + # We retrieve the room member handler here as to not cause a cyclic dependency + member_handler = self.hs.get_room_member_handler() + member_handler.ratelimit_invite(event.room_id, event.state_key) + # keep a record of the room version, if we don't yet know it. # (this may get overwritten if we later get a different room version in a # join dance). diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py index ee27d99135..07b2187eb1 100644 --- a/synapse/handlers/room.py +++ b/synapse/handlers/room.py @@ -126,6 +126,10 @@ class RoomCreationHandler(BaseHandler): self.third_party_event_rules = hs.get_third_party_event_rules() + self._invite_burst_count = ( + hs.config.ratelimiting.rc_invites_per_room.burst_count + ) + async def upgrade_room( self, requester: Requester, old_room_id: str, new_version: RoomVersion ) -> str: @@ -662,6 +666,9 @@ class RoomCreationHandler(BaseHandler): invite_3pid_list = [] invite_list = [] + if len(invite_list) + len(invite_3pid_list) > self._invite_burst_count: + raise SynapseError(400, "Cannot invite so many users at once") + await self.event_creation_handler.assert_accepted_privacy_policy(requester) power_level_content_override = config.get("power_level_content_override") diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py index e001e418f9..d335da6f19 100644 --- a/synapse/handlers/room_member.py +++ b/synapse/handlers/room_member.py @@ -85,6 +85,17 @@ class RoomMemberHandler(metaclass=abc.ABCMeta): burst_count=hs.config.ratelimiting.rc_joins_remote.burst_count, ) + self._invites_per_room_limiter = Ratelimiter( + clock=self.clock, + rate_hz=hs.config.ratelimiting.rc_invites_per_room.per_second, + burst_count=hs.config.ratelimiting.rc_invites_per_room.burst_count, + ) + self._invites_per_user_limiter = Ratelimiter( + clock=self.clock, + rate_hz=hs.config.ratelimiting.rc_invites_per_user.per_second, + burst_count=hs.config.ratelimiting.rc_invites_per_user.burst_count, + ) + # This is only used to get at ratelimit function, and # maybe_kick_guest_users. It's fine there are multiple of these as # it doesn't store state. @@ -144,6 +155,12 @@ class RoomMemberHandler(metaclass=abc.ABCMeta): """ raise NotImplementedError() + def ratelimit_invite(self, room_id: str, invitee_user_id: str): + """Ratelimit invites by room and by target user. + """ + self._invites_per_room_limiter.ratelimit(room_id) + self._invites_per_user_limiter.ratelimit(invitee_user_id) + async def _local_membership_update( self, requester: Requester, @@ -387,8 +404,12 @@ class RoomMemberHandler(metaclass=abc.ABCMeta): raise SynapseError(403, "This room has been blocked on this server") if effective_membership_state == Membership.INVITE: + target_id = target.to_string() + if ratelimit: + self.ratelimit_invite(room_id, target_id) + # block any attempts to invite the server notices mxid - if target.to_string() == self._server_notices_mxid: + if target_id == self._server_notices_mxid: raise SynapseError(HTTPStatus.FORBIDDEN, "Cannot invite this user") block_invite = False @@ -412,7 +433,7 @@ class RoomMemberHandler(metaclass=abc.ABCMeta): block_invite = True if not await self.spam_checker.user_may_invite( - requester.user.to_string(), target.to_string(), room_id + requester.user.to_string(), target_id, room_id ): logger.info("Blocking invite due to spam checker") block_invite = True diff --git a/tests/handlers/test_federation.py b/tests/handlers/test_federation.py index 0b24b89a2e..74503112f5 100644 --- a/tests/handlers/test_federation.py +++ b/tests/handlers/test_federation.py @@ -16,7 +16,7 @@ import logging from unittest import TestCase from synapse.api.constants import EventTypes -from synapse.api.errors import AuthError, Codes, SynapseError +from synapse.api.errors import AuthError, Codes, LimitExceededError, SynapseError from synapse.api.room_versions import RoomVersions from synapse.events import EventBase from synapse.federation.federation_base import event_from_pdu_json @@ -191,6 +191,97 @@ class FederationTestCase(unittest.HomeserverTestCase): self.assertEqual(sg, sg2) + @unittest.override_config( + {"rc_invites": {"per_room": {"per_second": 0.5, "burst_count": 3}}} + ) + def test_invite_by_room_ratelimit(self): + """Tests that invites from federation in a room are actually rate-limited. + """ + other_server = "otherserver" + other_user = "@otheruser:" + other_server + + # create the room + user_id = self.register_user("kermit", "test") + tok = self.login("kermit", "test") + room_id = self.helper.create_room_as(room_creator=user_id, tok=tok) + room_version = self.get_success(self.store.get_room_version(room_id)) + + def create_invite_for(local_user): + return event_from_pdu_json( + { + "type": EventTypes.Member, + "content": {"membership": "invite"}, + "room_id": room_id, + "sender": other_user, + "state_key": local_user, + "depth": 32, + "prev_events": [], + "auth_events": [], + "origin_server_ts": self.clock.time_msec(), + }, + room_version, + ) + + for i in range(3): + self.get_success( + self.handler.on_invite_request( + other_server, + create_invite_for("@user-%d:test" % (i,)), + room_version, + ) + ) + + self.get_failure( + self.handler.on_invite_request( + other_server, create_invite_for("@user-4:test"), room_version, + ), + exc=LimitExceededError, + ) + + @unittest.override_config( + {"rc_invites": {"per_user": {"per_second": 0.5, "burst_count": 3}}} + ) + def test_invite_by_user_ratelimit(self): + """Tests that invites from federation to a particular user are + actually rate-limited. + """ + other_server = "otherserver" + other_user = "@otheruser:" + other_server + + # create the room + user_id = self.register_user("kermit", "test") + tok = self.login("kermit", "test") + + def create_invite(): + room_id = self.helper.create_room_as(room_creator=user_id, tok=tok) + room_version = self.get_success(self.store.get_room_version(room_id)) + return event_from_pdu_json( + { + "type": EventTypes.Member, + "content": {"membership": "invite"}, + "room_id": room_id, + "sender": other_user, + "state_key": "@user:test", + "depth": 32, + "prev_events": [], + "auth_events": [], + "origin_server_ts": self.clock.time_msec(), + }, + room_version, + ) + + for i in range(3): + event = create_invite() + self.get_success( + self.handler.on_invite_request(other_server, event, event.room_version,) + ) + + event = create_invite() + self.get_failure( + self.handler.on_invite_request(other_server, event, event.room_version,), + exc=LimitExceededError, + ) + def _build_and_send_join_event(self, other_server, other_user, room_id): join_event = self.get_success( self.handler.on_make_join_request(other_server, room_id, other_user) diff --git a/tests/rest/client/v1/test_rooms.py b/tests/rest/client/v1/test_rooms.py index d4e3165436..2548b3a80c 100644 --- a/tests/rest/client/v1/test_rooms.py +++ b/tests/rest/client/v1/test_rooms.py @@ -616,6 +616,41 @@ class RoomMemberStateTestCase(RoomBase): self.assertEquals(json.loads(content), channel.json_body) +class RoomInviteRatelimitTestCase(RoomBase): + user_id = "@sid1:red" + + servlets = [ + admin.register_servlets, + profile.register_servlets, + room.register_servlets, + ] + + @unittest.override_config( + {"rc_invites": {"per_room": {"per_second": 0.5, "burst_count": 3}}} + ) + def test_invites_by_rooms_ratelimit(self): + """Tests that invites in a room are actually rate-limited.""" + room_id = self.helper.create_room_as(self.user_id) + + for i in range(3): + self.helper.invite(room_id, self.user_id, "@user-%s:red" % (i,)) + + self.helper.invite(room_id, self.user_id, "@user-4:red", expect_code=429) + + @unittest.override_config( + {"rc_invites": {"per_user": {"per_second": 0.5, "burst_count": 3}}} + ) + def test_invites_by_users_ratelimit(self): + """Tests that invites to a specific user are actually rate-limited.""" + + for i in range(3): + room_id = self.helper.create_room_as(self.user_id) + self.helper.invite(room_id, self.user_id, "@other-users:red") + + room_id = self.helper.create_room_as(self.user_id) + self.helper.invite(room_id, self.user_id, "@other-users:red", expect_code=429) + + class RoomJoinRatelimitTestCase(RoomBase): user_id = "@sid1:red"