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Diffstat (limited to 'synapse/handlers/federation_event.py')
| -rw-r--r-- | synapse/handlers/federation_event.py | 1825 |
1 files changed, 1825 insertions, 0 deletions
diff --git a/synapse/handlers/federation_event.py b/synapse/handlers/federation_event.py new file mode 100644 index 0000000000..9f055f00cf --- /dev/null +++ b/synapse/handlers/federation_event.py @@ -0,0 +1,1825 @@ +# Copyright 2021 The Matrix.org Foundation C.I.C. +# +# 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 logging +from http import HTTPStatus +from typing import ( + TYPE_CHECKING, + Collection, + Container, + Dict, + Iterable, + List, + Optional, + Sequence, + Set, + Tuple, +) + +import attr +from prometheus_client import Counter + +from twisted.internet import defer + +from synapse import event_auth +from synapse.api.constants import ( + EventContentFields, + EventTypes, + Membership, + RejectedReason, + RoomEncryptionAlgorithms, +) +from synapse.api.errors import ( + AuthError, + Codes, + FederationError, + HttpResponseException, + RequestSendFailed, + SynapseError, +) +from synapse.api.room_versions import KNOWN_ROOM_VERSIONS +from synapse.event_auth import auth_types_for_event +from synapse.events import EventBase +from synapse.events.snapshot import EventContext +from synapse.federation.federation_client import InvalidResponseError +from synapse.handlers._base import BaseHandler +from synapse.logging.context import ( + make_deferred_yieldable, + nested_logging_context, + run_in_background, +) +from synapse.logging.utils import log_function +from synapse.metrics.background_process_metrics import run_as_background_process +from synapse.replication.http.devices import ReplicationUserDevicesResyncRestServlet +from synapse.replication.http.federation import ( + ReplicationFederationSendEventsRestServlet, +) +from synapse.state import StateResolutionStore +from synapse.storage.databases.main.events_worker import EventRedactBehaviour +from synapse.types import ( + MutableStateMap, + PersistedEventPosition, + RoomStreamToken, + StateMap, + UserID, + get_domain_from_id, +) +from synapse.util.async_helpers import Linearizer, concurrently_execute +from synapse.util.iterutils import batch_iter +from synapse.util.retryutils import NotRetryingDestination +from synapse.util.stringutils import shortstr + +if TYPE_CHECKING: + from synapse.server import HomeServer + + +logger = logging.getLogger(__name__) + +soft_failed_event_counter = Counter( + "synapse_federation_soft_failed_events_total", + "Events received over federation that we marked as soft_failed", +) + + +@attr.s(slots=True, frozen=True, auto_attribs=True) +class _NewEventInfo: + """Holds information about a received event, ready for passing to _auth_and_persist_events + + Attributes: + event: the received event + + claimed_auth_event_map: a map of (type, state_key) => event for the event's + claimed auth_events. + + This can include events which have not yet been persisted, in the case that + we are backfilling a batch of events. + + Note: May be incomplete: if we were unable to find all of the claimed auth + events. Also, treat the contents with caution: the events might also have + been rejected, might not yet have been authorized themselves, or they might + be in the wrong room. + + """ + + event: EventBase + claimed_auth_event_map: StateMap[EventBase] + + +class FederationEventHandler(BaseHandler): + """Handles events that originated from federation. + + Responsible for handing incoming events and passing them on to the rest + of the homeserver (including auth and state conflict resolutions) + """ + + def __init__(self, hs: "HomeServer"): + super().__init__(hs) + + self.store = hs.get_datastore() + self.storage = hs.get_storage() + self.state_store = self.storage.state + + self.state_handler = hs.get_state_handler() + self.event_creation_handler = hs.get_event_creation_handler() + self._event_auth_handler = hs.get_event_auth_handler() + self._message_handler = hs.get_message_handler() + self.action_generator = hs.get_action_generator() + self._state_resolution_handler = hs.get_state_resolution_handler() + + self.federation_client = hs.get_federation_client() + self.third_party_event_rules = hs.get_third_party_event_rules() + + self.is_mine_id = hs.is_mine_id + self._instance_name = hs.get_instance_name() + + self.config = hs.config + self._ephemeral_messages_enabled = hs.config.server.enable_ephemeral_messages + + self._send_events = ReplicationFederationSendEventsRestServlet.make_client(hs) + if hs.config.worker_app: + self._user_device_resync = ( + ReplicationUserDevicesResyncRestServlet.make_client(hs) + ) + else: + self._device_list_updater = hs.get_device_handler().device_list_updater + + # When joining a room we need to queue any events for that room up. + # For each room, a list of (pdu, origin) tuples. + # TODO: replace this with something more elegant, probably based around the + # federation event staging area. + self.room_queues: Dict[str, List[Tuple[EventBase, str]]] = {} + + self._room_pdu_linearizer = Linearizer("fed_room_pdu") + + async def on_receive_pdu(self, origin: str, pdu: EventBase) -> None: + """Process a PDU received via a federation /send/ transaction + + Args: + origin: server which initiated the /send/ transaction. Will + be used to fetch missing events or state. + pdu: received PDU + """ + + room_id = pdu.room_id + event_id = pdu.event_id + + # We reprocess pdus when we have seen them only as outliers + existing = await self.store.get_event( + event_id, allow_none=True, allow_rejected=True + ) + + # FIXME: Currently we fetch an event again when we already have it + # if it has been marked as an outlier. + if existing: + if not existing.internal_metadata.is_outlier(): + logger.info( + "Ignoring received event %s which we have already seen", event_id + ) + return + if pdu.internal_metadata.is_outlier(): + logger.info( + "Ignoring received outlier %s which we already have as an outlier", + event_id, + ) + return + logger.info("De-outliering event %s", event_id) + + # do some initial sanity-checking of the event. In particular, make + # sure it doesn't have hundreds of prev_events or auth_events, which + # could cause a huge state resolution or cascade of event fetches. + try: + self._sanity_check_event(pdu) + except SynapseError as err: + logger.warning("Received event failed sanity checks") + raise FederationError("ERROR", err.code, err.msg, affected=pdu.event_id) + + # If we are currently in the process of joining this room, then we + # queue up events for later processing. + if room_id in self.room_queues: + logger.info( + "Queuing PDU from %s for now: join in progress", + origin, + ) + self.room_queues[room_id].append((pdu, origin)) + return + + # If we're not in the room just ditch the event entirely. This is + # probably an old server that has come back and thinks we're still in + # the room (or we've been rejoined to the room by a state reset). + # + # Note that if we were never in the room then we would have already + # dropped the event, since we wouldn't know the room version. + is_in_room = await self._event_auth_handler.check_host_in_room( + room_id, self.server_name + ) + if not is_in_room: + logger.info( + "Ignoring PDU from %s as we're not in the room", + origin, + ) + return None + + # Check that the event passes auth based on the state at the event. This is + # done for events that are to be added to the timeline (non-outliers). + # + # Get missing pdus if necessary: + # - Fetching any missing prev events to fill in gaps in the graph + # - Fetching state if we have a hole in the graph + if not pdu.internal_metadata.is_outlier(): + prevs = set(pdu.prev_event_ids()) + seen = await self.store.have_events_in_timeline(prevs) + missing_prevs = prevs - seen + + if missing_prevs: + # We only backfill backwards to the min depth. + min_depth = await self.get_min_depth_for_context(pdu.room_id) + logger.debug("min_depth: %d", min_depth) + + if min_depth is not None and pdu.depth > min_depth: + # If we're missing stuff, ensure we only fetch stuff one + # at a time. + logger.info( + "Acquiring room lock to fetch %d missing prev_events: %s", + len(missing_prevs), + shortstr(missing_prevs), + ) + with (await self._room_pdu_linearizer.queue(pdu.room_id)): + logger.info( + "Acquired room lock to fetch %d missing prev_events", + len(missing_prevs), + ) + + try: + await self._get_missing_events_for_pdu( + origin, pdu, prevs, min_depth + ) + except Exception as e: + raise Exception( + "Error fetching missing prev_events for %s: %s" + % (event_id, e) + ) from e + + # Update the set of things we've seen after trying to + # fetch the missing stuff + seen = await self.store.have_events_in_timeline(prevs) + missing_prevs = prevs - seen + + if not missing_prevs: + logger.info("Found all missing prev_events") + + if missing_prevs: + # since this event was pushed to us, it is possible for it to + # become the only forward-extremity in the room, and we would then + # trust its state to be the state for the whole room. This is very + # bad. Further, if the event was pushed to us, there is no excuse + # for us not to have all the prev_events. (XXX: apart from + # min_depth?) + # + # We therefore reject any such events. + logger.warning( + "Rejecting: failed to fetch %d prev events: %s", + len(missing_prevs), + shortstr(missing_prevs), + ) + raise FederationError( + "ERROR", + 403, + ( + "Your server isn't divulging details about prev_events " + "referenced in this event." + ), + affected=pdu.event_id, + ) + + await self._process_received_pdu(origin, pdu, state=None) + + @log_function + async def on_send_membership_event( + self, origin: str, event: EventBase + ) -> Tuple[EventBase, EventContext]: + """ + We have received a join/leave/knock event for a room via send_join/leave/knock. + + Verify that event and send it into the room on the remote homeserver's behalf. + + This is quite similar to on_receive_pdu, with the following principal + differences: + * only membership events are permitted (and only events with + sender==state_key -- ie, no kicks or bans) + * *We* send out the event on behalf of the remote server. + * We enforce the membership restrictions of restricted rooms. + * Rejected events result in an exception rather than being stored. + + There are also other differences, however it is not clear if these are by + design or omission. In particular, we do not attempt to backfill any missing + prev_events. + + Args: + origin: The homeserver of the remote (joining/invited/knocking) user. + event: The member event that has been signed by the remote homeserver. + + Returns: + The event and context of the event after inserting it into the room graph. + + Raises: + SynapseError if the event is not accepted into the room + """ + logger.debug( + "on_send_membership_event: Got event: %s, signatures: %s", + event.event_id, + event.signatures, + ) + + if get_domain_from_id(event.sender) != origin: + logger.info( + "Got send_membership request for user %r from different origin %s", + event.sender, + origin, + ) + raise SynapseError(403, "User not from origin", Codes.FORBIDDEN) + + if event.sender != event.state_key: + raise SynapseError(400, "state_key and sender must match", Codes.BAD_JSON) + + assert not event.internal_metadata.outlier + + # Send this event on behalf of the other server. + # + # The remote server isn't a full participant in the room at this point, so + # may not have an up-to-date list of the other homeservers participating in + # the room, so we send it on their behalf. + 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) + if context.rejected: + raise SynapseError( + 403, f"{event.membership} event was rejected", Codes.FORBIDDEN + ) + + # for joins, we need to check the restrictions of restricted rooms + if event.membership == Membership.JOIN: + await self.check_join_restrictions(context, event) + + # for knock events, we run the third-party event rules. It's not entirely clear + # why we don't do this for other sorts of membership events. + if event.membership == Membership.KNOCK: + event_allowed, _ = await self.third_party_event_rules.check_event_allowed( + event, context + ) + if not event_allowed: + logger.info("Sending of knock %s forbidden by third-party rules", event) + raise SynapseError( + 403, "This event is not allowed in this context", Codes.FORBIDDEN + ) + + # all looks good, we can persist the event. + await self._run_push_actions_and_persist_event(event, context) + return event, context + + async def check_join_restrictions( + self, context: EventContext, event: EventBase + ) -> None: + """Check that restrictions in restricted join rules are matched + + Called when we receive a join event via send_join. + + Raises an auth error if the restrictions are not matched. + """ + prev_state_ids = await context.get_prev_state_ids() + + # Check if the user is already in the room or invited to the room. + user_id = event.state_key + prev_member_event_id = prev_state_ids.get((EventTypes.Member, user_id), None) + prev_member_event = None + if prev_member_event_id: + prev_member_event = await self.store.get_event(prev_member_event_id) + + # Check if the member should be allowed access via membership in a space. + await self._event_auth_handler.check_restricted_join_rules( + prev_state_ids, + event.room_version, + user_id, + prev_member_event, + ) + + @log_function + async def backfill( + self, dest: str, room_id: str, limit: int, extremities: List[str] + ) -> None: + """Trigger a backfill request to `dest` for the given `room_id` + + This will attempt to get more events from the remote. If the other side + has no new events to offer, this will return an empty list. + + As the events are received, we check their signatures, and also do some + sanity-checking on them. If any of the backfilled events are invalid, + this method throws a SynapseError. + + We might also raise an InvalidResponseError if the response from the remote + server is just bogus. + + TODO: make this more useful to distinguish failures of the remote + server from invalid events (there is probably no point in trying to + re-fetch invalid events from every other HS in the room.) + """ + if dest == self.server_name: + raise SynapseError(400, "Can't backfill from self.") + + events = await self.federation_client.backfill( + dest, room_id, limit=limit, extremities=extremities + ) + + if not events: + return + + # if there are any events in the wrong room, the remote server is buggy and + # should not be trusted. + for ev in events: + if ev.room_id != room_id: + raise InvalidResponseError( + f"Remote server {dest} returned event {ev.event_id} which is in " + f"room {ev.room_id}, when we were backfilling in {room_id}" + ) + + await self._process_pulled_events(dest, events, backfilled=True) + + async def _get_missing_events_for_pdu( + self, origin: str, pdu: EventBase, prevs: Set[str], min_depth: int + ) -> None: + """ + Args: + origin: Origin of the pdu. Will be called to get the missing events + pdu: received pdu + prevs: List of event ids which we are missing + min_depth: Minimum depth of events to return. + """ + + room_id = pdu.room_id + event_id = pdu.event_id + + seen = await self.store.have_events_in_timeline(prevs) + + if not prevs - seen: + return + + latest_list = await self.store.get_latest_event_ids_in_room(room_id) + + # We add the prev events that we have seen to the latest + # list to ensure the remote server doesn't give them to us + latest = set(latest_list) + latest |= seen + + logger.info( + "Requesting missing events between %s and %s", + shortstr(latest), + event_id, + ) + + # XXX: we set timeout to 10s to help workaround + # https://github.com/matrix-org/synapse/issues/1733. + # The reason is to avoid holding the linearizer lock + # whilst processing inbound /send transactions, causing + # FDs to stack up and block other inbound transactions + # which empirically can currently take up to 30 minutes. + # + # N.B. this explicitly disables retry attempts. + # + # N.B. this also increases our chances of falling back to + # fetching fresh state for the room if the missing event + # can't be found, which slightly reduces our security. + # it may also increase our DAG extremity count for the room, + # causing additional state resolution? See #1760. + # However, fetching state doesn't hold the linearizer lock + # apparently. + # + # see https://github.com/matrix-org/synapse/pull/1744 + # + # ---- + # + # Update richvdh 2018/09/18: There are a number of problems with timing this + # request out aggressively on the client side: + # + # - it plays badly with the server-side rate-limiter, which starts tarpitting you + # if you send too many requests at once, so you end up with the server carefully + # working through the backlog of your requests, which you have already timed + # out. + # + # - for this request in particular, we now (as of + # https://github.com/matrix-org/synapse/pull/3456) reject any PDUs where the + # server can't produce a plausible-looking set of prev_events - so we becone + # much more likely to reject the event. + # + # - contrary to what it says above, we do *not* fall back to fetching fresh state + # for the room if get_missing_events times out. Rather, we give up processing + # the PDU whose prevs we are missing, which then makes it much more likely that + # we'll end up back here for the *next* PDU in the list, which exacerbates the + # problem. + # + # - the aggressive 10s timeout was introduced to deal with incoming federation + # requests taking 8 hours to process. It's not entirely clear why that was going + # on; certainly there were other issues causing traffic storms which are now + # resolved, and I think in any case we may be more sensible about our locking + # now. We're *certainly* more sensible about our logging. + # + # All that said: Let's try increasing the timeout to 60s and see what happens. + + try: + missing_events = await self.federation_client.get_missing_events( + origin, + room_id, + earliest_events_ids=list(latest), + latest_events=[pdu], + limit=10, + min_depth=min_depth, + timeout=60000, + ) + except (RequestSendFailed, HttpResponseException, NotRetryingDestination) as e: + # We failed to get the missing events, but since we need to handle + # the case of `get_missing_events` not returning the necessary + # events anyway, it is safe to simply log the error and continue. + logger.warning("Failed to get prev_events: %s", e) + return + + logger.info("Got %d prev_events", len(missing_events)) + await self._process_pulled_events(origin, missing_events, backfilled=False) + + async def _process_pulled_events( + self, origin: str, events: Iterable[EventBase], backfilled: bool + ) -> None: + """Process a batch of events we have pulled from a remote server + + Pulls in any events required to auth the events, persists the received events, + and notifies clients, if appropriate. + + Assumes the events have already had their signatures and hashes checked. + + Params: + origin: The server we received these events from + events: The received events. + backfilled: True if this is part of a historical batch of events (inhibits + notification to clients, and validation of device keys.) + """ + + # We want to sort these by depth so we process them and + # tell clients about them in order. + sorted_events = sorted(events, key=lambda x: x.depth) + + for ev in sorted_events: + with nested_logging_context(ev.event_id): + await self._process_pulled_event(origin, ev, backfilled=backfilled) + + async def _process_pulled_event( + self, origin: str, event: EventBase, backfilled: bool + ) -> None: + """Process a single event that we have pulled from a remote server + + Pulls in any events required to auth the event, persists the received event, + and notifies clients, if appropriate. + + Assumes the event has already had its signatures and hashes checked. + + This is somewhat equivalent to on_receive_pdu, but applies somewhat different + logic in the case that we are missing prev_events (in particular, it just + requests the state at that point, rather than triggering a get_missing_events) - + so is appropriate when we have pulled the event from a remote server, rather + than having it pushed to us. + + Params: + origin: The server we received this event from + events: The received event + backfilled: True if this is part of a historical batch of events (inhibits + notification to clients, and validation of device keys.) + """ + logger.info("Processing pulled event %s", event) + + # these should not be outliers. + assert not event.internal_metadata.is_outlier() + + event_id = event.event_id + + existing = await self.store.get_event( + event_id, allow_none=True, allow_rejected=True + ) + if existing: + if not existing.internal_metadata.is_outlier(): + logger.info( + "Ignoring received event %s which we have already seen", + event_id, + ) + return + logger.info("De-outliering event %s", event_id) + + try: + self._sanity_check_event(event) + except SynapseError as err: + logger.warning("Event %s failed sanity check: %s", event_id, err) + return + + try: + state = await self._resolve_state_at_missing_prevs(origin, event) + await self._process_received_pdu( + origin, event, state=state, backfilled=backfilled + ) + except FederationError as e: + if e.code == 403: + logger.warning("Pulled event %s failed history check.", event_id) + else: + raise + + async def _resolve_state_at_missing_prevs( + self, dest: str, event: EventBase + ) -> Optional[Iterable[EventBase]]: + """Calculate the state at an event with missing prev_events. + + This is used when we have pulled a batch of events from a remote server, and + still don't have all the prev_events. + + If we already have all the prev_events for `event`, this method does nothing. + + Otherwise, the missing prevs become new backwards extremities, and we fall back + to asking the remote server for the state after each missing `prev_event`, + and resolving across them. + + That's ok provided we then resolve the state against other bits of the DAG + before using it - in other words, that the received event `event` is not going + to become the only forwards_extremity in the room (which will ensure that you + can't just take over a room by sending an event, withholding its prev_events, + and declaring yourself to be an admin in the subsequent state request). + + In other words: we should only call this method if `event` has been *pulled* + as part of a batch of missing prev events, or similar. + + Params: + dest: the remote server to ask for state at the missing prevs. Typically, + this will be the server we got `event` from. + event: an event to check for missing prevs. + + Returns: + if we already had all the prev events, `None`. Otherwise, returns a list of + the events in the state at `event`. + """ + room_id = event.room_id + event_id = event.event_id + + prevs = set(event.prev_event_ids()) + seen = await self.store.have_events_in_timeline(prevs) + missing_prevs = prevs - seen + + if not missing_prevs: + return None + + logger.info( + "Event %s is missing prev_events %s: calculating state for a " + "backwards extremity", + event_id, + shortstr(missing_prevs), + ) + # Calculate the state after each of the previous events, and + # resolve them to find the correct state at the current event. + event_map = {event_id: event} + try: + # Get the state of the events we know about + ours = await self.state_store.get_state_groups_ids(room_id, seen) + + # state_maps is a list of mappings from (type, state_key) to event_id + state_maps: List[StateMap[str]] = list(ours.values()) + + # we don't need this any more, let's delete it. + del ours + + # Ask the remote server for the states we don't + # know about + for p in missing_prevs: + logger.info("Requesting state after missing prev_event %s", p) + + with nested_logging_context(p): + # note that if any of the missing prevs share missing state or + # auth events, the requests to fetch those events are deduped + # by the get_pdu_cache in federation_client. + remote_state = await self._get_state_after_missing_prev_event( + dest, room_id, p + ) + + remote_state_map = { + (x.type, x.state_key): x.event_id for x in remote_state + } + state_maps.append(remote_state_map) + + for x in remote_state: + event_map[x.event_id] = x + + room_version = await self.store.get_room_version_id(room_id) + state_map = await self._state_resolution_handler.resolve_events_with_store( + room_id, + room_version, + state_maps, + event_map, + state_res_store=StateResolutionStore(self.store), + ) + + # We need to give _process_received_pdu the actual state events + # rather than event ids, so generate that now. + + # First though we need to fetch all the events that are in + # state_map, so we can build up the state below. + evs = await self.store.get_events( + list(state_map.values()), + get_prev_content=False, + redact_behaviour=EventRedactBehaviour.AS_IS, + ) + event_map.update(evs) + + state = [event_map[e] for e in state_map.values()] + except Exception: + logger.warning( + "Error attempting to resolve state at missing prev_events", + exc_info=True, + ) + raise FederationError( + "ERROR", + 403, + "We can't get valid state history.", + affected=event_id, + ) + return state + + async def _get_state_after_missing_prev_event( + self, + destination: str, + room_id: str, + event_id: str, + ) -> List[EventBase]: + """Requests all of the room state at a given event from a remote homeserver. + + Args: + destination: The remote homeserver to query for the state. + room_id: The id of the room we're interested in. + event_id: The id of the event we want the state at. + + Returns: + A list of events in the state, including the event itself + """ + ( + state_event_ids, + auth_event_ids, + ) = await self.federation_client.get_room_state_ids( + destination, room_id, event_id=event_id + ) + + logger.debug( + "state_ids returned %i state events, %i auth events", + len(state_event_ids), + len(auth_event_ids), + ) + + # start by just trying to fetch the events from the store + desired_events = set(state_event_ids) + desired_events.add(event_id) + logger.debug("Fetching %i events from cache/store", len(desired_events)) + fetched_events = await self.store.get_events( + desired_events, allow_rejected=True + ) + + missing_desired_events = desired_events - fetched_events.keys() + logger.debug( + "We are missing %i events (got %i)", + len(missing_desired_events), + len(fetched_events), + ) + + # We probably won't need most of the auth events, so let's just check which + # we have for now, rather than thrashing the event cache with them all + # unnecessarily. + + # TODO: we probably won't actually need all of the auth events, since we + # already have a bunch of the state events. It would be nice if the + # federation api gave us a way of finding out which we actually need. + + missing_auth_events = set(auth_event_ids) - fetched_events.keys() + missing_auth_events.difference_update( + await self.store.have_seen_events(room_id, missing_auth_events) + ) + logger.debug("We are also missing %i auth events", len(missing_auth_events)) + + missing_events = missing_desired_events | missing_auth_events + logger.debug("Fetching %i events from remote", len(missing_events)) + await self._get_events_and_persist( + destination=destination, room_id=room_id, events=missing_events + ) + + # we need to make sure we re-load from the database to get the rejected + # state correct. + fetched_events.update( + await self.store.get_events(missing_desired_events, allow_rejected=True) + ) + + # check for events which were in the wrong room. + # + # this can happen if a remote server claims that the state or + # auth_events at an event in room A are actually events in room B + + bad_events = [ + (event_id, event.room_id) + for event_id, event in fetched_events.items() + if event.room_id != room_id + ] + + for bad_event_id, bad_room_id in bad_events: + # This is a bogus situation, but since we may only discover it a long time + # after it happened, we try our best to carry on, by just omitting the + # bad events from the returned state set. + logger.warning( + "Remote server %s claims event %s in room %s is an auth/state " + "event in room %s", + destination, + bad_event_id, + bad_room_id, + room_id, + ) + + del fetched_events[bad_event_id] + + # if we couldn't get the prev event in question, that's a problem. + remote_event = fetched_events.get(event_id) + if not remote_event: + raise Exception("Unable to get missing prev_event %s" % (event_id,)) + + # missing state at that event is a warning, not a blocker + # XXX: this doesn't sound right? it means that we'll end up with incomplete + # state. + failed_to_fetch = desired_events - fetched_events.keys() + if failed_to_fetch: + logger.warning( + "Failed to fetch missing state events for %s %s", + event_id, + failed_to_fetch, + ) + + remote_state = [ + fetched_events[e_id] for e_id in state_event_ids if e_id in fetched_events + ] + + if remote_event.is_state() and remote_event.rejected_reason is None: + remote_state.append(remote_event) + + return remote_state + + async def _process_received_pdu( + self, + origin: str, + event: EventBase, + state: Optional[Iterable[EventBase]], + backfilled: bool = False, + ) -> None: + """Called when we have a new pdu. We need to do auth checks and put it + through the StateHandler. + + Args: + origin: server sending the event + + event: event to be persisted + + state: Normally None, but if we are handling a gap in the graph + (ie, we are missing one or more prev_events), the resolved state at the + event + + backfilled: True if this is part of a historical batch of events (inhibits + notification to clients, and validation of device keys.) + """ + logger.debug("Processing event: %s", event) + + try: + context = await self.state_handler.compute_event_context( + event, old_state=state + ) + await self._auth_and_persist_event( + origin, event, context, state=state, backfilled=backfilled + ) + except AuthError as e: + raise FederationError("ERROR", e.code, e.msg, affected=event.event_id) + + if backfilled: + return + + # For encrypted messages we check that we know about the sending device, + # if we don't then we mark the device cache for that user as stale. + if event.type == EventTypes.Encrypted: + device_id = event.content.get("device_id") + sender_key = event.content.get("sender_key") + + cached_devices = await self.store.get_cached_devices_for_user(event.sender) + + resync = False # Whether we should resync device lists. + + device = None + if device_id is not None: + device = cached_devices.get(device_id) + if device is None: + logger.info( + "Received event from remote device not in our cache: %s %s", + event.sender, + device_id, + ) + resync = True + + # We also check if the `sender_key` matches what we expect. + if sender_key is not None: + # Figure out what sender key we're expecting. If we know the + # device and recognize the algorithm then we can work out the + # exact key to expect. Otherwise check it matches any key we + # have for that device. + + current_keys: Container[str] = [] + + if device: + keys = device.get("keys", {}).get("keys", {}) + + if ( + event.content.get("algorithm") + == RoomEncryptionAlgorithms.MEGOLM_V1_AES_SHA2 + ): + # For this algorithm we expect a curve25519 key. + key_name = "curve25519:%s" % (device_id,) + current_keys = [keys.get(key_name)] + else: + # We don't know understand the algorithm, so we just + # check it matches a key for the device. + current_keys = keys.values() + elif device_id: + # We don't have any keys for the device ID. + pass + else: + # The event didn't include a device ID, so we just look for + # keys across all devices. + current_keys = [ + key + for device in cached_devices.values() + for key in device.get("keys", {}).get("keys", {}).values() + ] + + # We now check that the sender key matches (one of) the expected + # keys. + if sender_key not in current_keys: + logger.info( + "Received event from remote device with unexpected sender key: %s %s: %s", + event.sender, + device_id or "<no device_id>", + sender_key, + ) + resync = True + + if resync: + run_as_background_process( + "resync_device_due_to_pdu", + self._resync_device, + event.sender, + ) + + await self._handle_marker_event(origin, event) + + async def _resync_device(self, sender: str) -> None: + """We have detected that the device list for the given user may be out + of sync, so we try and resync them. + """ + + try: + await self.store.mark_remote_user_device_cache_as_stale(sender) + + # Immediately attempt a resync in the background + if self.config.worker_app: + await self._user_device_resync(user_id=sender) + else: + await self._device_list_updater.user_device_resync(sender) + except Exception: + logger.exception("Failed to resync device for %s", sender) + + async def _handle_marker_event(self, origin: str, marker_event: EventBase): + """Handles backfilling the insertion event when we receive a marker + event that points to one. + + Args: + origin: Origin of the event. Will be called to get the insertion event + marker_event: The event to process + """ + + if marker_event.type != EventTypes.MSC2716_MARKER: + # Not a marker event + return + + if marker_event.rejected_reason is not None: + # Rejected event + return + + # Skip processing a marker event if the room version doesn't + # support it. + room_version = await self.store.get_room_version(marker_event.room_id) + if not room_version.msc2716_historical: + return + + logger.debug("_handle_marker_event: received %s", marker_event) + + insertion_event_id = marker_event.content.get( + EventContentFields.MSC2716_MARKER_INSERTION + ) + + if insertion_event_id is None: + # Nothing to retrieve then (invalid marker) + return + + logger.debug( + "_handle_marker_event: backfilling insertion event %s", insertion_event_id + ) + + await self._get_events_and_persist( + origin, + marker_event.room_id, + [insertion_event_id], + ) + + insertion_event = await self.store.get_event( + insertion_event_id, allow_none=True + ) + if insertion_event is None: + logger.warning( + "_handle_marker_event: server %s didn't return insertion event %s for marker %s", + origin, + insertion_event_id, + marker_event.event_id, + ) + return + + logger.debug( + "_handle_marker_event: succesfully backfilled insertion event %s from marker event %s", + insertion_event, + marker_event, + ) + + await self.store.insert_insertion_extremity( + insertion_event_id, marker_event.room_id + ) + + logger.debug( + "_handle_marker_event: insertion extremity added for %s from marker event %s", + insertion_event, + marker_event, + ) + + async def _get_events_and_persist( + self, destination: str, room_id: str, events: Iterable[str] + ) -> None: + """Fetch the given events from a server, and persist them as outliers. + + This function *does not* recursively get missing auth events of the + newly fetched events. Callers must include in the `events` argument + any missing events from the auth chain. + + Logs a warning if we can't find the given event. + """ + + room_version = await self.store.get_room_version(room_id) + + event_map: Dict[str, EventBase] = {} + + async def get_event(event_id: str): + with nested_logging_context(event_id): + try: + event = await self.federation_client.get_pdu( + [destination], + event_id, + room_version, + outlier=True, + ) + if event is None: + logger.warning( + "Server %s didn't return event %s", + destination, + event_id, + ) + return + + event_map[event.event_id] = event + + except Exception as e: + logger.warning( + "Error fetching missing state/auth event %s: %s %s", + event_id, + type(e), + e, + ) + + await concurrently_execute(get_event, events, 5) + + # Make a map of auth events for each event. We do this after fetching + # all the events as some of the events' auth events will be in the list + # of requested events. + + auth_events = [ + aid + for event in event_map.values() + for aid in event.auth_event_ids() + if aid not in event_map + ] + persisted_events = await self.store.get_events( + auth_events, + allow_rejected=True, + ) + + event_infos = [] + for event in event_map.values(): + auth = {} + for auth_event_id in event.auth_event_ids(): + ae = persisted_events.get(auth_event_id) or event_map.get(auth_event_id) + if ae: + auth[(ae.type, ae.state_key)] = ae + else: + logger.info("Missing auth event %s", auth_event_id) + + event_infos.append(_NewEventInfo(event, auth)) + + if event_infos: + await self._auth_and_persist_events( + destination, + room_id, + event_infos, + ) + + async def _auth_and_persist_events( + self, + origin: str, + room_id: str, + event_infos: Collection[_NewEventInfo], + ) -> None: + """Creates the appropriate contexts and persists events. The events + should not depend on one another, e.g. this should be used to persist + a bunch of outliers, but not a chunk of individual events that depend + on each other for state calculations. + + Notifies about the events where appropriate. + """ + + if not event_infos: + return + + async def prep(ev_info: _NewEventInfo): + event = ev_info.event + with nested_logging_context(suffix=event.event_id): + res = await self.state_handler.compute_event_context(event) + res = await self._check_event_auth( + origin, + event, + res, + claimed_auth_event_map=ev_info.claimed_auth_event_map, + ) + return res + + contexts = await make_deferred_yieldable( + defer.gatherResults( + [run_in_background(prep, ev_info) for ev_info in event_infos], + consumeErrors=True, + ) + ) + + await self.persist_events_and_notify( + room_id, + [ + (ev_info.event, context) + for ev_info, context in zip(event_infos, contexts) + ], + ) + + async def _auth_and_persist_event( + self, + origin: str, + event: EventBase, + context: EventContext, + state: Optional[Iterable[EventBase]] = None, + claimed_auth_event_map: Optional[StateMap[EventBase]] = None, + backfilled: bool = False, + ) -> None: + """ + Process an event by performing auth checks and then persisting to the database. + + Args: + origin: The host the event originates from. + event: The event itself. + context: + The event context. + + state: + The state events used to check the event for soft-fail. If this is + not provided the current state events will be used. + + claimed_auth_event_map: + A map of (type, state_key) => event for the event's claimed auth_events. + Possibly incomplete, and possibly including events that are not yet + persisted, or authed, or in the right room. + + Only populated where we may not already have persisted these events - + for example, when populating outliers. + + backfilled: True if the event was backfilled. + """ + context = await self._check_event_auth( + origin, + event, + context, + state=state, + claimed_auth_event_map=claimed_auth_event_map, + backfilled=backfilled, + ) + + await self._run_push_actions_and_persist_event(event, context, backfilled) + + async def _check_event_auth( + self, + origin: str, + event: EventBase, + context: EventContext, + state: Optional[Iterable[EventBase]] = None, + claimed_auth_event_map: Optional[StateMap[EventBase]] = None, + backfilled: bool = False, + ) -> EventContext: + """ + Checks whether an event should be rejected (for failing auth checks). + + Args: + origin: The host the event originates from. + event: The event itself. + context: + The event context. + + state: + The state events used to check the event for soft-fail. If this is + not provided the current state events will be used. + + claimed_auth_event_map: + A map of (type, state_key) => event for the event's claimed auth_events. + Possibly incomplete, and possibly including events that are not yet + persisted, or authed, or in the right room. + + Only populated where we may not already have persisted these events - + for example, when populating outliers, or the state for a backwards + extremity. + + backfilled: True if the event was backfilled. + + Returns: + The updated context object. + """ + room_version = await self.store.get_room_version_id(event.room_id) + room_version_obj = KNOWN_ROOM_VERSIONS[room_version] + + if claimed_auth_event_map: + # if we have a copy of the auth events from the event, use that as the + # basis for auth. + auth_events = claimed_auth_event_map + else: + # otherwise, we calculate what the auth events *should* be, and use that + prev_state_ids = await context.get_prev_state_ids() + auth_events_ids = self._event_auth_handler.compute_auth_events( + event, prev_state_ids, for_verification=True + ) + auth_events_x = await self.store.get_events(auth_events_ids) + auth_events = {(e.type, e.state_key): e for e in auth_events_x.values()} + + try: + ( + context, + auth_events_for_auth, + ) = await self._update_auth_events_and_context_for_auth( + origin, event, context, auth_events + ) + 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, + ) + auth_events_for_auth = auth_events + + try: + event_auth.check(room_version_obj, event, auth_events=auth_events_for_auth) + except AuthError as e: + logger.warning("Failed auth resolution for %r because %s", event, e) + context.rejected = RejectedReason.AUTH_ERROR + + if not context.rejected: + await self._check_for_soft_fail(event, state, backfilled, origin=origin) + + if event.type == EventTypes.GuestAccess and not context.rejected: + await self.maybe_kick_guest_users(event) + + # If we are going to send this event over federation we precaclculate + # the joined hosts. + if event.internal_metadata.get_send_on_behalf_of(): + await self.event_creation_handler.cache_joined_hosts_for_event( + event, context + ) + + return context + + async def _check_for_soft_fail( + self, + event: EventBase, + state: Optional[Iterable[EventBase]], + backfilled: bool, + origin: str, + ) -> None: + """Checks if we should soft fail the event; if so, marks the event as + such. + + Args: + event + state: The state at the event if we don't have all the event's prev events + backfilled: Whether the event is from backfill + origin: The host the event originates from. + """ + # For new (non-backfilled and non-outlier) events we check if the event + # passes auth based on the current state. If it doesn't then we + # "soft-fail" the event. + if backfilled or event.internal_metadata.is_outlier(): + return + + extrem_ids_list = await self.store.get_latest_event_ids_in_room(event.room_id) + extrem_ids = set(extrem_ids_list) + prev_event_ids = set(event.prev_event_ids()) + + if extrem_ids == prev_event_ids: + # If they're the same then the current state is the same as the + # state at the event, so no point rechecking auth for soft fail. + return + + room_version = await self.store.get_room_version_id(event.room_id) + room_version_obj = KNOWN_ROOM_VERSIONS[room_version] + + # Calculate the "current state". + if state is not None: + # If we're explicitly given the state then we won't have all the + # prev events, and so we have a gap in the graph. In this case + # we want to be a little careful as we might have been down for + # a while and have an incorrect view of the current state, + # however we still want to do checks as gaps are easy to + # maliciously manufacture. + # + # So we use a "current state" that is actually a state + # resolution across the current forward extremities and the + # given state at the event. This should correctly handle cases + # like bans, especially with state res v2. + + state_sets_d = await self.state_store.get_state_groups( + event.room_id, extrem_ids + ) + state_sets: List[Iterable[EventBase]] = list(state_sets_d.values()) + state_sets.append(state) + current_states = await self.state_handler.resolve_events( + room_version, state_sets, event + ) + current_state_ids: StateMap[str] = { + k: e.event_id for k, e in current_states.items() + } + else: + current_state_ids = await self.state_handler.get_current_state_ids( + event.room_id, latest_event_ids=extrem_ids + ) + + logger.debug( + "Doing soft-fail check for %s: state %s", + event.event_id, + current_state_ids, + ) + + # Now check if event pass auth against said current state + auth_types = auth_types_for_event(room_version_obj, event) + current_state_ids_list = [ + e for k, e in current_state_ids.items() if k in auth_types + ] + + auth_events_map = await self.store.get_events(current_state_ids_list) + current_auth_events = { + (e.type, e.state_key): e for e in auth_events_map.values() + } + + try: + event_auth.check(room_version_obj, event, auth_events=current_auth_events) + except AuthError as e: + logger.warning( + "Soft-failing %r (from %s) because %s", + event, + e, + origin, + extra={ + "room_id": event.room_id, + "mxid": event.sender, + "hs": origin, + }, + ) + soft_failed_event_counter.inc() + event.internal_metadata.soft_failed = True + + async def _update_auth_events_and_context_for_auth( + self, + origin: str, + event: EventBase, + context: EventContext, + input_auth_events: StateMap[EventBase], + ) -> Tuple[EventContext, 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: + origin: + event: + context: + + input_auth_events: + 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. + + Returns: + updated context, updated auth event map + """ + # take a copy of input_auth_events before we modify it. + auth_events: MutableStateMap[EventBase] = dict(input_auth_events) + + 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/. + 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) + + 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: + try: + remote_auth_chain = await self.federation_client.get_event_auth( + origin, event.room_id, event.event_id + ) + except RequestSendFailed as e1: + # The other side isn't around or doesn't implement the + # endpoint, so lets just bail out. + logger.info("Failed to get event auth from remote: %s", e1) + return context, auth_events + + seen_remotes = await self.store.have_seen_events( + event.room_id, [e.event_id for e in remote_auth_chain] + ) + + for e in remote_auth_chain: + if e.event_id in seen_remotes: + continue + + if e.event_id == event.event_id: + continue + + try: + auth_ids = e.auth_event_ids() + auth = { + (e.type, e.state_key): e + for e in remote_auth_chain + if e.event_id in auth_ids or e.type == EventTypes.Create + } + e.internal_metadata.outlier = True + + logger.debug( + "_check_event_auth %s missing_auth: %s", + event.event_id, + e.event_id, + ) + missing_auth_event_context = ( + await self.state_handler.compute_event_context(e) + ) + await self._auth_and_persist_event( + origin, + e, + missing_auth_event_context, + claimed_auth_event_map=auth, + ) + + if e.event_id in event_auth_events: + auth_events[(e.type, e.state_key)] = e + except AuthError: + pass + + except Exception: + 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, auth_events + + different_auth = event_auth_events.difference( + e.event_id for e in auth_events.values() + ) + + if not different_auth: + return context, auth_events + + 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) + + 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 + + # 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) + 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 + ) + + logger.info( + "After state res: updating auth_events with new state %s", + { + (d.type, d.state_key): d.event_id + for d in new_state.values() + if auth_events.get((d.type, d.state_key)) != d + }, + ) + + auth_events.update(new_state) + + context = await self._update_context_for_auth_events( + event, context, auth_events + ) + + return context, 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_store.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( + state_group=state_group, + state_group_before_event=context.state_group_before_event, + current_state_ids=current_state_ids, + prev_state_ids=prev_state_ids, + prev_group=prev_group, + delta_ids=state_updates, + ) + + async def _run_push_actions_and_persist_event( + self, event: EventBase, context: EventContext, backfilled: bool = False + ): + """Run the push actions for a received event, and persist it. + + Args: + event: The event itself. + context: The event context. + backfilled: True if the event was backfilled. + """ + try: + if ( + not event.internal_metadata.is_outlier() + and not backfilled + and not context.rejected + and (await self.store.get_min_depth(event.room_id)) <= event.depth + ): + await self.action_generator.handle_push_actions_for_event( + event, context + ) + + await self.persist_events_and_notify( + event.room_id, [(event, context)], backfilled=backfilled + ) + except Exception: + run_in_background( + self.store.remove_push_actions_from_staging, event.event_id + ) + raise + + async def persist_events_and_notify( + self, + room_id: str, + event_and_contexts: Sequence[Tuple[EventBase, EventContext]], + backfilled: bool = False, + ) -> int: + """Persists events and tells the notifier/pushers about them, if + necessary. + + Args: + room_id: The room ID of events being persisted. + event_and_contexts: Sequence of events with their associated + context that should be persisted. All events must belong to + the same room. + backfilled: Whether these events are a result of + backfilling or not + + Returns: + The stream ID after which all events have been persisted. + """ + if not event_and_contexts: + return self.store.get_current_events_token() + + instance = self.config.worker.events_shard_config.get_instance(room_id) + if instance != self._instance_name: + # Limit the number of events sent over replication. We choose 200 + # here as that is what we default to in `max_request_body_size(..)` + for batch in batch_iter(event_and_contexts, 200): + result = await self._send_events( + instance_name=instance, + store=self.store, + room_id=room_id, + event_and_contexts=batch, + backfilled=backfilled, + ) + return result["max_stream_id"] + else: + assert self.storage.persistence + + # Note that this returns the events that were persisted, which may not be + # the same as were passed in if some were deduplicated due to transaction IDs. + events, max_stream_token = await self.storage.persistence.persist_events( + event_and_contexts, backfilled=backfilled + ) + + if self._ephemeral_messages_enabled: + for event in events: + # If there's an expiry timestamp on the event, schedule its expiry. + self._message_handler.maybe_schedule_expiry(event) + + if not backfilled: # Never notify for backfilled events + for event in events: + await self._notify_persisted_event(event, max_stream_token) + + return max_stream_token.stream + + async def _notify_persisted_event( + self, event: EventBase, max_stream_token: RoomStreamToken + ) -> None: + """Checks to see if notifier/pushers should be notified about the + event or not. + + Args: + event: + max_stream_token: The max_stream_id returned by persist_events + """ + + extra_users = [] + if event.type == EventTypes.Member: + target_user_id = event.state_key + + # We notify for memberships if its an invite for one of our + # users + if event.internal_metadata.is_outlier(): + if event.membership != Membership.INVITE: + if not self.is_mine_id(target_user_id): + return + + target_user = UserID.from_string(target_user_id) + extra_users.append(target_user) + elif event.internal_metadata.is_outlier(): + return + + # the event has been persisted so it should have a stream ordering. + assert event.internal_metadata.stream_ordering + + event_pos = PersistedEventPosition( + self._instance_name, event.internal_metadata.stream_ordering + ) + self.notifier.on_new_room_event( + event, event_pos, max_stream_token, extra_users=extra_users + ) + + def _sanity_check_event(self, ev: EventBase) -> None: + """ + Do some early sanity checks of a received event + + In particular, checks it doesn't have an excessive number of + prev_events or auth_events, which could cause a huge state resolution + or cascade of event fetches. + + Args: + ev: event to be checked + + Raises: + SynapseError if the event does not pass muster + """ + if len(ev.prev_event_ids()) > 20: + logger.warning( + "Rejecting event %s which has %i prev_events", + ev.event_id, + len(ev.prev_event_ids()), + ) + raise SynapseError(HTTPStatus.BAD_REQUEST, "Too many prev_events") + + if len(ev.auth_event_ids()) > 10: + logger.warning( + "Rejecting event %s which has %i auth_events", + ev.event_id, + len(ev.auth_event_ids()), + ) + raise SynapseError(HTTPStatus.BAD_REQUEST, "Too many auth_events") + + async def get_min_depth_for_context(self, context: str) -> int: + return await self.store.get_min_depth(context) |