diff options
| -rw-r--r-- | changelog.d/6343.misc | 1 | ||||
| -rw-r--r-- | synapse/handlers/federation.py | 83 |
2 files changed, 49 insertions, 35 deletions
diff --git a/changelog.d/6343.misc b/changelog.d/6343.misc new file mode 100644 index 0000000000..d9a44389b9 --- /dev/null +++ b/changelog.d/6343.misc @@ -0,0 +1 @@ +Refactor some code in the event authentication path for clarity. diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py index 0e904f2da0..66852153c4 100644 --- a/synapse/handlers/federation.py +++ b/synapse/handlers/federation.py @@ -2040,8 +2040,10 @@ class FederationHandler(BaseHandler): auth_events (dict[(str, str)->synapse.events.EventBase]): Map from (event_type, state_key) to event - What we expect the event's auth_events to be, based on the event's - position in the dag. I think? maybe?? + Normally, our calculated auth_events based on the state of the room + at the event's position in the DAG, though occasionally (eg if the + event is an outlier), may be the auth events claimed by the remote + server. Also NB that this function adds entries to it. Returns: @@ -2091,30 +2093,35 @@ class FederationHandler(BaseHandler): origin (str): event (synapse.events.EventBase): context (synapse.events.snapshot.EventContext): + auth_events (dict[(str, str)->synapse.events.EventBase]): + Map from (event_type, state_key) to event + + Normally, our calculated auth_events based on the state of the room + at the event's position in the DAG, though occasionally (eg if the + event is an outlier), may be the auth events claimed by the remote + server. + + Also NB that this function adds entries to it. Returns: defer.Deferred[EventContext]: updated context """ event_auth_events = set(event.auth_event_ids()) - if event.is_state(): - event_key = (event.type, event.state_key) - else: - event_key = None - - # if the event's auth_events refers to events which are not in our - # calculated auth_events, we need to fetch those events from somewhere. - # - # we start by fetching them from the store, and then try calling /event_auth/. + # 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/. if missing_auth: # TODO: can we use store.have_seen_events here instead? have_events = yield self.store.get_seen_events_with_rejections(missing_auth) - logger.debug("Got events %s from store", have_events) + logger.debug("Found events %s in the store", have_events) missing_auth.difference_update(have_events.keys()) else: have_events = {} @@ -2169,15 +2176,23 @@ class FederationHandler(BaseHandler): event.auth_event_ids() ) except Exception: - # FIXME: logger.exception("Failed to get auth chain") if event.internal_metadata.is_outlier(): + # XXX: given that, for an outlier, we'll be working with the + # event's *claimed* auth events rather than those we calculated: + # (a) is there any point in this test, since different_auth below will + # obviously be empty + # (b) alternatively, why don't we do it earlier? logger.info("Skipping auth_event fetch for outlier") return context # FIXME: Assumes we have and stored all the state for all the # prev_events + # + # FIXME: what does the fixme above mean? where do prev_events come into + # it, why do we care about the state for those events, and what does "have and + # stored" mean? Seems erik wrote it in c1d860870b different_auth = event_auth_events.difference( e.event_id for e in auth_events.values() ) @@ -2191,27 +2206,22 @@ class FederationHandler(BaseHandler): different_auth, ) + # now we state-resolve between our own idea of the auth events, and the remote's + # idea of them. + room_version = yield self.store.get_room_version(event.room_id) + different_event_ids = [ + d for d in different_auth if d in have_events and not have_events[d] + ] - different_events = yield make_deferred_yieldable( - defer.gatherResults( - [ - run_in_background( - self.store.get_event, d, allow_none=True, allow_rejected=False - ) - for d in different_auth - if d in have_events and not have_events[d] - ], - consumeErrors=True, - ) - ).addErrback(unwrapFirstError) + if different_event_ids: + # XXX: currently this checks for redactions but I'm not convinced that is + # necessary? + different_events = yield self.store.get_events_as_list(different_event_ids) - if different_events: local_view = dict(auth_events) remote_view = dict(auth_events) - remote_view.update( - {(d.type, d.state_key): d for d in different_events if d} - ) + remote_view.update({(d.type, d.state_key): d for d in different_events}) new_state = yield self.state_handler.resolve_events( room_version, @@ -2231,13 +2241,13 @@ class FederationHandler(BaseHandler): auth_events.update(new_state) context = yield self._update_context_for_auth_events( - event, context, auth_events, event_key + event, context, auth_events ) return context @defer.inlineCallbacks - def _update_context_for_auth_events(self, event, context, auth_events, event_key): + def _update_context_for_auth_events(self, event, context, auth_events): """Update the state_ids in an event context after auth event resolution, storing the changes as a new state group. @@ -2246,18 +2256,21 @@ class FederationHandler(BaseHandler): context (synapse.events.snapshot.EventContext): initial event context - auth_events (dict[(str, str)->str]): Events to update in the event + auth_events (dict[(str, str)->EventBase]): Events to update in the event context. - event_key ((str, str)): (type, state_key) for the current event. - this will not be included in the current_state in the context. - Returns: Deferred[EventContext]: new event context """ + # exclude the state key of the new event from the current_state in the context. + if event.is_state(): + event_key = (event.type, event.state_key) + else: + event_key = None state_updates = { k: a.event_id for k, a in iteritems(auth_events) if k != event_key } + current_state_ids = yield context.get_current_state_ids(self.store) current_state_ids = dict(current_state_ids) |