diff options
Diffstat (limited to 'synapse/handlers/federation_event.py')
| -rw-r--r-- | synapse/handlers/federation_event.py | 277 |
1 files changed, 82 insertions, 195 deletions
diff --git a/synapse/handlers/federation_event.py b/synapse/handlers/federation_event.py index c74117c19a..b1dab57447 100644 --- a/synapse/handlers/federation_event.py +++ b/synapse/handlers/federation_event.py @@ -12,6 +12,7 @@ # See the License for the specific language governing permissions and # limitations under the License. +import collections import itertools import logging from http import HTTPStatus @@ -347,7 +348,7 @@ class FederationEventHandler: event.internal_metadata.send_on_behalf_of = origin context = await self._state_handler.compute_event_context(event) - context = await self._check_event_auth(origin, event, context) + await self._check_event_auth(origin, event, context) if context.rejected: raise SynapseError( 403, f"{event.membership} event was rejected", Codes.FORBIDDEN @@ -485,7 +486,7 @@ class FederationEventHandler: partial_state=partial_state, ) - context = await self._check_event_auth(origin, event, context) + await self._check_event_auth(origin, event, context) if context.rejected: raise SynapseError(400, "Join event was rejected") @@ -1116,11 +1117,7 @@ class FederationEventHandler: state_ids_before_event=state_ids, ) try: - context = await self._check_event_auth( - origin, - event, - context, - ) + await self._check_event_auth(origin, event, context) except AuthError as e: # This happens only if we couldn't find the auth events. We'll already have # logged a warning, so now we just convert to a FederationError. @@ -1495,11 +1492,8 @@ class FederationEventHandler: ) async def _check_event_auth( - self, - origin: str, - event: EventBase, - context: EventContext, - ) -> EventContext: + self, origin: str, event: EventBase, context: EventContext + ) -> None: """ Checks whether an event should be rejected (for failing auth checks). @@ -1509,9 +1503,6 @@ class FederationEventHandler: context: The event context. - Returns: - The updated context object. - Raises: AuthError if we were unable to find copies of the event's auth events. (Most other failures just cause us to set `context.rejected`.) @@ -1526,7 +1517,7 @@ class FederationEventHandler: logger.warning("While validating received event %r: %s", event, e) # TODO: use a different rejected reason here? context.rejected = RejectedReason.AUTH_ERROR - return context + return # next, check that we have all of the event's auth events. # @@ -1538,6 +1529,9 @@ class FederationEventHandler: ) # ... and check that the event passes auth at those auth events. + # https://spec.matrix.org/v1.3/server-server-api/#checks-performed-on-receipt-of-a-pdu: + # 4. Passes authorization rules based on the event’s auth events, + # otherwise it is rejected. try: await check_state_independent_auth_rules(self._store, event) check_state_dependent_auth_rules(event, claimed_auth_events) @@ -1546,55 +1540,90 @@ class FederationEventHandler: "While checking auth of %r against auth_events: %s", event, e ) context.rejected = RejectedReason.AUTH_ERROR - return context + return + + # now check the auth rules pass against the room state before the event + # https://spec.matrix.org/v1.3/server-server-api/#checks-performed-on-receipt-of-a-pdu: + # 5. Passes authorization rules based on the state before the event, + # otherwise it is rejected. + # + # ... however, if we only have partial state for the room, then there is a good + # chance that we'll be missing some of the state needed to auth the new event. + # So, we state-resolve the auth events that we are given against the state that + # we know about, which ensures things like bans are applied. (Note that we'll + # already have checked we have all the auth events, in + # _load_or_fetch_auth_events_for_event above) + if context.partial_state: + room_version = await self._store.get_room_version_id(event.room_id) + + local_state_id_map = await context.get_prev_state_ids() + claimed_auth_events_id_map = { + (ev.type, ev.state_key): ev.event_id for ev in claimed_auth_events + } + + state_for_auth_id_map = ( + await self._state_resolution_handler.resolve_events_with_store( + event.room_id, + room_version, + [local_state_id_map, claimed_auth_events_id_map], + event_map=None, + state_res_store=StateResolutionStore(self._store), + ) + ) + else: + event_types = event_auth.auth_types_for_event(event.room_version, event) + state_for_auth_id_map = await context.get_prev_state_ids( + StateFilter.from_types(event_types) + ) - # now check auth against what we think the auth events *should* be. - event_types = event_auth.auth_types_for_event(event.room_version, event) - prev_state_ids = await context.get_prev_state_ids( - StateFilter.from_types(event_types) + calculated_auth_event_ids = self._event_auth_handler.compute_auth_events( + event, state_for_auth_id_map, for_verification=True ) - auth_events_ids = self._event_auth_handler.compute_auth_events( - event, prev_state_ids, for_verification=True + # if those are the same, we're done here. + if collections.Counter(event.auth_event_ids()) == collections.Counter( + calculated_auth_event_ids + ): + return + + # otherwise, re-run the auth checks based on what we calculated. + calculated_auth_events = await self._store.get_events_as_list( + calculated_auth_event_ids ) - auth_events_x = await self._store.get_events(auth_events_ids) + + # log the differences + + claimed_auth_event_map = {(e.type, e.state_key): e for e in claimed_auth_events} calculated_auth_event_map = { - (e.type, e.state_key): e for e in auth_events_x.values() + (e.type, e.state_key): e for e in calculated_auth_events } + logger.info( + "event's auth_events are different to our calculated auth_events. " + "Claimed but not calculated: %s. Calculated but not claimed: %s", + [ + ev + for k, ev in claimed_auth_event_map.items() + if k not in calculated_auth_event_map + or calculated_auth_event_map[k].event_id != ev.event_id + ], + [ + ev + for k, ev in calculated_auth_event_map.items() + if k not in claimed_auth_event_map + or claimed_auth_event_map[k].event_id != ev.event_id + ], + ) try: - updated_auth_events = await self._update_auth_events_for_auth( + check_state_dependent_auth_rules(event, calculated_auth_events) + except AuthError as e: + logger.warning( + "While checking auth of %r against room state before the event: %s", event, - calculated_auth_event_map=calculated_auth_event_map, - ) - except Exception: - # We don't really mind if the above fails, so lets not fail - # processing if it does. However, it really shouldn't fail so - # let's still log as an exception since we'll still want to fix - # any bugs. - logger.exception( - "Failed to double check auth events for %s with remote. " - "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 + e, ) - auth_events_for_auth = updated_auth_events - else: - auth_events_for_auth = calculated_auth_event_map - - try: - check_state_dependent_auth_rules(event, auth_events_for_auth.values()) - except AuthError as e: - logger.warning("Failed auth resolution for %r because %s", event, e) context.rejected = RejectedReason.AUTH_ERROR - return context - async def _maybe_kick_guest_users(self, event: EventBase) -> None: if event.type != EventTypes.GuestAccess: return @@ -1704,93 +1733,6 @@ class FederationEventHandler: soft_failed_event_counter.inc() event.internal_metadata.soft_failed = True - async def _update_auth_events_for_auth( - self, - event: EventBase, - calculated_auth_event_map: 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 - doesn't then we talk to the remote server to compare state to see if - we can come to a consensus (e.g. if one server missed some valid - state). - - This attempts to resolve any potential divergence of state between - servers, but is not essential and so failures should not block further - processing of the event. - - Args: - event: - - 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 auth event map, or None if no changes are needed. - - """ - assert not event.internal_metadata.outlier - - # 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()) - different_auth = event_auth_events.difference( - e.event_id for e in calculated_auth_event_map.values() - ) - - if not different_auth: - return None - - logger.info( - "auth_events refers to events which are not in our calculated auth " - "chain: %s", - different_auth, - ) - - # XXX: currently this checks for redactions but I'm not convinced that is - # 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: - 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 = 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() - - room_version = await self._store.get_room_version_id(event.room_id) - 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", - different_state.values(), - ) - - # 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 ) -> Collection[EventBase]: @@ -1888,61 +1830,6 @@ class FederationEventHandler: await self._auth_and_persist_outliers(room_id, remote_auth_events) - async def _update_context_for_auth_events( - self, event: EventBase, context: EventContext, auth_events: StateMap[EventBase] - ) -> EventContext: - """Update the state_ids in an event context after auth event resolution, - storing the changes as a new state group. - - Args: - event: The event we're handling the context for - - context: initial event context - - auth_events: Events to update in the event context. - - Returns: - new event context - """ - # exclude the state key of the new event from the current_state in the context. - if event.is_state(): - event_key: Optional[Tuple[str, str]] = (event.type, event.state_key) - else: - event_key = None - state_updates = { - k: a.event_id for k, a in auth_events.items() if k != event_key - } - - current_state_ids = await context.get_current_state_ids() - current_state_ids = dict(current_state_ids) # type: ignore - - current_state_ids.update(state_updates) - - prev_state_ids = await context.get_prev_state_ids() - prev_state_ids = dict(prev_state_ids) - - prev_state_ids.update({k: a.event_id for k, a in auth_events.items()}) - - # create a new state group as a delta from the existing one. - prev_group = context.state_group - state_group = await self._state_storage_controller.store_state_group( - event.event_id, - event.room_id, - prev_group=prev_group, - delta_ids=state_updates, - current_state_ids=current_state_ids, - ) - - return EventContext.with_state( - storage=self._storage_controllers, - state_group=state_group, - state_group_before_event=context.state_group_before_event, - state_delta_due_to_event=state_updates, - prev_group=prev_group, - delta_ids=state_updates, - partial_state=context.partial_state, - ) - async def _run_push_actions_and_persist_event( self, event: EventBase, context: EventContext, backfilled: bool = False ) -> None: |