diff options
Diffstat (limited to '')
| -rw-r--r-- | changelog.d/11122.misc | 1 | ||||
| -rw-r--r-- | synapse/handlers/federation_event.py | 151 |
2 files changed, 38 insertions, 114 deletions
diff --git a/changelog.d/11122.misc b/changelog.d/11122.misc new file mode 100644 index 0000000000..9a765435db --- /dev/null +++ b/changelog.d/11122.misc @@ -0,0 +1 @@ +Clean up some of the federation event authentication code for clarity. diff --git a/synapse/handlers/federation_event.py b/synapse/handlers/federation_event.py index 5a2f2e5ebb..3431a80ab4 100644 --- a/synapse/handlers/federation_event.py +++ b/synapse/handlers/federation_event.py @@ -65,7 +65,6 @@ from synapse.replication.http.federation import ( from synapse.state import StateResolutionStore from synapse.storage.databases.main.events_worker import EventRedactBehaviour from synapse.types import ( - MutableStateMap, PersistedEventPosition, RoomStreamToken, StateMap, @@ -1417,13 +1416,8 @@ class FederationEventHandler: } try: - ( - context, - auth_events_for_auth, - ) = await self._update_auth_events_and_context_for_auth( - origin, + updated_auth_events = await self._update_auth_events_for_auth( event, - context, calculated_auth_event_map=calculated_auth_event_map, ) except Exception: @@ -1436,6 +1430,14 @@ class FederationEventHandler: "Ignoring failure and continuing processing of event.", event.event_id, ) + updated_auth_events = None + + if updated_auth_events: + context = await self._update_context_for_auth_events( + event, context, updated_auth_events + ) + auth_events_for_auth = updated_auth_events + else: auth_events_for_auth = calculated_auth_event_map try: @@ -1560,13 +1562,11 @@ class FederationEventHandler: soft_failed_event_counter.inc() event.internal_metadata.soft_failed = True - async def _update_auth_events_and_context_for_auth( + async def _update_auth_events_for_auth( self, - origin: str, event: EventBase, - context: EventContext, calculated_auth_event_map: StateMap[EventBase], - ) -> Tuple[EventContext, StateMap[EventBase]]: + ) -> Optional[StateMap[EventBase]]: """Helper for _check_event_auth. See there for docs. Checks whether a given event has the expected auth events. If it @@ -1579,96 +1579,27 @@ class FederationEventHandler: processing of the event. Args: - origin: event: - context: calculated_auth_event_map: Our calculated auth_events based on the state of the room at the event's position in the DAG. Returns: - updated context, updated auth event map + updated auth event map, or None if no changes are needed. + """ assert not event.internal_metadata.outlier - # take a copy of calculated_auth_event_map before we modify it. - auth_events: MutableStateMap[EventBase] = dict(calculated_auth_event_map) - + # check for events which are in the event's claimed auth_events, but not + # in our calculated event map. event_auth_events = set(event.auth_event_ids()) - - # missing_auth is the set of the event's auth_events which we don't yet have - # in auth_events. - missing_auth = event_auth_events.difference( - e.event_id for e in auth_events.values() - ) - - # if we have missing events, we need to fetch those events from somewhere. - # - # we start by checking if they are in the store, and then try calling /event_auth/. - # - # TODO: this code is now redundant, since it should be impossible for us to - # get here without already having the auth events. - if missing_auth: - have_events = await self._store.have_seen_events( - event.room_id, missing_auth - ) - logger.debug("Events %s are in the store", have_events) - missing_auth.difference_update(have_events) - - # missing_auth is now the set of event_ids which: - # a. are listed in event.auth_events, *and* - # b. are *not* part of our calculated auth events based on room state, *and* - # c. are *not* yet in our database. - - if missing_auth: - # If we don't have all the auth events, we need to get them. - logger.info("auth_events contains unknown events: %s", missing_auth) - try: - await self._get_remote_auth_chain_for_event( - origin, event.room_id, event.event_id - ) - except Exception: - logger.exception("Failed to get auth chain") - else: - # load any auth events we might have persisted from the database. This - # has the side-effect of correctly setting the rejected_reason on them. - auth_events.update( - { - (ae.type, ae.state_key): ae - for ae in await self._store.get_events_as_list( - missing_auth, allow_rejected=True - ) - } - ) - - # auth_events now contains - # 1. our *calculated* auth events based on the room state, plus: - # 2. any events which: - # a. are listed in `event.auth_events`, *and* - # b. are not part of our calculated auth events, *and* - # c. were not in our database before the call to /event_auth - # d. have since been added to our database (most likely by /event_auth). - different_auth = event_auth_events.difference( - e.event_id for e in auth_events.values() + e.event_id for e in calculated_auth_event_map.values() ) - # different_auth is the set of events which *are* in `event.auth_events`, but - # which are *not* in `auth_events`. Comparing with (2.) above, this means - # exclusively the set of `event.auth_events` which we already had in our - # database before any call to /event_auth. - # - # I'm reasonably sure that the fact that events returned by /event_auth are - # blindly added to auth_events (and hence excluded from different_auth) is a bug - # - though it's a very long-standing one (see - # https://github.com/matrix-org/synapse/commit/78015948a7febb18e000651f72f8f58830a55b93#diff-0bc92da3d703202f5b9be2d3f845e375f5b1a6bc6ba61705a8af9be1121f5e42R786 - # from Jan 2015 which seems to add it, though it actually just moves it from - # elsewhere (before that, it gets lost in a mess of huge "various bug fixes" - # PRs). - if not different_auth: - return context, auth_events + return None logger.info( "auth_events refers to events which are not in our calculated auth " @@ -1680,27 +1611,18 @@ class FederationEventHandler: # necessary? different_events = await self._store.get_events_as_list(different_auth) + # double-check they're all in the same room - we should already have checked + # this but it doesn't hurt to check again. for d in different_events: - if d.room_id != event.room_id: - logger.warning( - "Event %s refers to auth_event %s which is in a different room", - event.event_id, - d.event_id, - ) - - # don't attempt to resolve the claimed auth events against our own - # in this case: just use our own auth events. - # - # XXX: should we reject the event in this case? It feels like we should, - # but then shouldn't we also do so if we've failed to fetch any of the - # auth events? - return context, auth_events + assert ( + d.room_id == event.room_id + ), f"Event {event.event_id} refers to auth_event {d.event_id} which is in a different room" # now we state-resolve between our own idea of the auth events, and the remote's # idea of them. - local_state = auth_events.values() - remote_auth_events = dict(auth_events) + local_state = calculated_auth_event_map.values() + remote_auth_events = dict(calculated_auth_event_map) remote_auth_events.update({(d.type, d.state_key): d for d in different_events}) remote_state = remote_auth_events.values() @@ -1708,23 +1630,24 @@ class FederationEventHandler: new_state = await self._state_handler.resolve_events( room_version, (local_state, remote_state), event ) + different_state = { + (d.type, d.state_key): d + for d in new_state.values() + if calculated_auth_event_map.get((d.type, d.state_key)) != d + } + if not different_state: + logger.info("State res returned no new state") + return None logger.info( "After state res: updating auth_events with new state %s", - { - d - for d in new_state.values() - if auth_events.get((d.type, d.state_key)) != d - }, + different_state.values(), ) - auth_events.update(new_state) - - context = await self._update_context_for_auth_events( - event, context, auth_events - ) - - return context, auth_events + # take a copy of calculated_auth_event_map before we modify it. + auth_events = dict(calculated_auth_event_map) + auth_events.update(different_state) + return auth_events async def _load_or_fetch_auth_events_for_event( self, destination: str, event: EventBase |