1978 lines
76 KiB
Python
1978 lines
76 KiB
Python
# Copyright 2021 The Matrix.org Foundation C.I.C.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import itertools
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import logging
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from http import HTTPStatus
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from typing import (
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TYPE_CHECKING,
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Collection,
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Container,
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Dict,
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Iterable,
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List,
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Optional,
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Sequence,
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Set,
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Tuple,
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)
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from prometheus_client import Counter
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from synapse.api.constants import (
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EventContentFields,
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EventTypes,
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GuestAccess,
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Membership,
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RejectedReason,
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RoomEncryptionAlgorithms,
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)
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from synapse.api.errors import (
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AuthError,
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Codes,
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FederationError,
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HttpResponseException,
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RequestSendFailed,
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SynapseError,
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)
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from synapse.api.room_versions import KNOWN_ROOM_VERSIONS, RoomVersion, RoomVersions
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from synapse.event_auth import (
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auth_types_for_event,
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check_auth_rules_for_event,
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validate_event_for_room_version,
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)
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from synapse.events import EventBase
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from synapse.events.snapshot import EventContext
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from synapse.federation.federation_client import InvalidResponseError
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from synapse.logging.context import nested_logging_context, run_in_background
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from synapse.logging.utils import log_function
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from synapse.metrics.background_process_metrics import run_as_background_process
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from synapse.replication.http.devices import ReplicationUserDevicesResyncRestServlet
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from synapse.replication.http.federation import (
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ReplicationFederationSendEventsRestServlet,
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)
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from synapse.state import StateResolutionStore
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from synapse.storage.databases.main.events_worker import EventRedactBehaviour
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from synapse.types import (
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PersistedEventPosition,
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RoomStreamToken,
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StateMap,
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UserID,
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get_domain_from_id,
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)
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from synapse.util.async_helpers import Linearizer, concurrently_execute
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from synapse.util.iterutils import batch_iter
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from synapse.util.retryutils import NotRetryingDestination
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from synapse.util.stringutils import shortstr
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if TYPE_CHECKING:
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from synapse.server import HomeServer
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logger = logging.getLogger(__name__)
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soft_failed_event_counter = Counter(
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"synapse_federation_soft_failed_events_total",
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"Events received over federation that we marked as soft_failed",
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)
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class FederationEventHandler:
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"""Handles events that originated from federation.
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Responsible for handing incoming events and passing them on to the rest
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of the homeserver (including auth and state conflict resolutions)
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"""
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def __init__(self, hs: "HomeServer"):
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self._store = hs.get_datastore()
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self._storage = hs.get_storage()
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self._state_store = self._storage.state
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self._state_handler = hs.get_state_handler()
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self._event_creation_handler = hs.get_event_creation_handler()
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self._event_auth_handler = hs.get_event_auth_handler()
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self._message_handler = hs.get_message_handler()
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self._action_generator = hs.get_action_generator()
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self._state_resolution_handler = hs.get_state_resolution_handler()
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# avoid a circular dependency by deferring execution here
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self._get_room_member_handler = hs.get_room_member_handler
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self._federation_client = hs.get_federation_client()
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self._third_party_event_rules = hs.get_third_party_event_rules()
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self._notifier = hs.get_notifier()
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self._is_mine_id = hs.is_mine_id
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self._server_name = hs.hostname
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self._instance_name = hs.get_instance_name()
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self._config = hs.config
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self._ephemeral_messages_enabled = hs.config.server.enable_ephemeral_messages
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self._send_events = ReplicationFederationSendEventsRestServlet.make_client(hs)
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if hs.config.worker.worker_app:
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self._user_device_resync = (
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ReplicationUserDevicesResyncRestServlet.make_client(hs)
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)
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else:
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self._device_list_updater = hs.get_device_handler().device_list_updater
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# When joining a room we need to queue any events for that room up.
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# For each room, a list of (pdu, origin) tuples.
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# TODO: replace this with something more elegant, probably based around the
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# federation event staging area.
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self.room_queues: Dict[str, List[Tuple[EventBase, str]]] = {}
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self._room_pdu_linearizer = Linearizer("fed_room_pdu")
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async def on_receive_pdu(self, origin: str, pdu: EventBase) -> None:
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"""Process a PDU received via a federation /send/ transaction
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Args:
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origin: server which initiated the /send/ transaction. Will
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be used to fetch missing events or state.
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pdu: received PDU
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"""
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# We should never see any outliers here.
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assert not pdu.internal_metadata.outlier
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room_id = pdu.room_id
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event_id = pdu.event_id
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# We reprocess pdus when we have seen them only as outliers
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existing = await self._store.get_event(
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event_id, allow_none=True, allow_rejected=True
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)
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# FIXME: Currently we fetch an event again when we already have it
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# if it has been marked as an outlier.
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if existing:
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if not existing.internal_metadata.is_outlier():
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logger.info(
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"Ignoring received event %s which we have already seen", event_id
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)
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return
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if pdu.internal_metadata.is_outlier():
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logger.info(
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"Ignoring received outlier %s which we already have as an outlier",
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event_id,
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)
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return
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logger.info("De-outliering event %s", event_id)
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# do some initial sanity-checking of the event. In particular, make
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# sure it doesn't have hundreds of prev_events or auth_events, which
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# could cause a huge state resolution or cascade of event fetches.
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try:
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self._sanity_check_event(pdu)
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except SynapseError as err:
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logger.warning("Received event failed sanity checks")
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raise FederationError("ERROR", err.code, err.msg, affected=pdu.event_id)
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# If we are currently in the process of joining this room, then we
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# queue up events for later processing.
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if room_id in self.room_queues:
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logger.info(
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"Queuing PDU from %s for now: join in progress",
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origin,
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)
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self.room_queues[room_id].append((pdu, origin))
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return
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# If we're not in the room just ditch the event entirely. This is
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# probably an old server that has come back and thinks we're still in
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# the room (or we've been rejoined to the room by a state reset).
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#
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# Note that if we were never in the room then we would have already
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# dropped the event, since we wouldn't know the room version.
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is_in_room = await self._event_auth_handler.check_host_in_room(
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room_id, self._server_name
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)
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if not is_in_room:
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logger.info(
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"Ignoring PDU from %s as we're not in the room",
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origin,
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)
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return None
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# Try to fetch any missing prev events to fill in gaps in the graph
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prevs = set(pdu.prev_event_ids())
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seen = await self._store.have_events_in_timeline(prevs)
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missing_prevs = prevs - seen
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if missing_prevs:
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# We only backfill backwards to the min depth.
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min_depth = await self._store.get_min_depth(pdu.room_id)
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logger.debug("min_depth: %d", min_depth)
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if min_depth is not None and pdu.depth > min_depth:
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# If we're missing stuff, ensure we only fetch stuff one
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# at a time.
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logger.info(
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"Acquiring room lock to fetch %d missing prev_events: %s",
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len(missing_prevs),
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shortstr(missing_prevs),
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)
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with (await self._room_pdu_linearizer.queue(pdu.room_id)):
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logger.info(
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"Acquired room lock to fetch %d missing prev_events",
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len(missing_prevs),
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)
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try:
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await self._get_missing_events_for_pdu(
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origin, pdu, prevs, min_depth
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)
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except Exception as e:
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raise Exception(
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"Error fetching missing prev_events for %s: %s"
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% (event_id, e)
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) from e
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# Update the set of things we've seen after trying to
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# fetch the missing stuff
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seen = await self._store.have_events_in_timeline(prevs)
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missing_prevs = prevs - seen
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if not missing_prevs:
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logger.info("Found all missing prev_events")
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if missing_prevs:
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# since this event was pushed to us, it is possible for it to
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# become the only forward-extremity in the room, and we would then
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# trust its state to be the state for the whole room. This is very
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# bad. Further, if the event was pushed to us, there is no excuse
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# for us not to have all the prev_events. (XXX: apart from
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# min_depth?)
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#
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# We therefore reject any such events.
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logger.warning(
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"Rejecting: failed to fetch %d prev events: %s",
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len(missing_prevs),
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shortstr(missing_prevs),
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)
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raise FederationError(
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"ERROR",
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403,
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(
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"Your server isn't divulging details about prev_events "
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"referenced in this event."
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),
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affected=pdu.event_id,
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)
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await self._process_received_pdu(origin, pdu, state=None)
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@log_function
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async def on_send_membership_event(
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self, origin: str, event: EventBase
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) -> Tuple[EventBase, EventContext]:
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"""
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We have received a join/leave/knock event for a room via send_join/leave/knock.
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Verify that event and send it into the room on the remote homeserver's behalf.
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This is quite similar to on_receive_pdu, with the following principal
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differences:
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* only membership events are permitted (and only events with
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sender==state_key -- ie, no kicks or bans)
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* *We* send out the event on behalf of the remote server.
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* We enforce the membership restrictions of restricted rooms.
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* Rejected events result in an exception rather than being stored.
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There are also other differences, however it is not clear if these are by
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design or omission. In particular, we do not attempt to backfill any missing
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prev_events.
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Args:
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origin: The homeserver of the remote (joining/invited/knocking) user.
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event: The member event that has been signed by the remote homeserver.
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Returns:
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The event and context of the event after inserting it into the room graph.
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Raises:
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SynapseError if the event is not accepted into the room
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"""
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logger.debug(
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"on_send_membership_event: Got event: %s, signatures: %s",
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event.event_id,
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event.signatures,
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)
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if get_domain_from_id(event.sender) != origin:
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logger.info(
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"Got send_membership request for user %r from different origin %s",
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event.sender,
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origin,
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)
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raise SynapseError(403, "User not from origin", Codes.FORBIDDEN)
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if event.sender != event.state_key:
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raise SynapseError(400, "state_key and sender must match", Codes.BAD_JSON)
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assert not event.internal_metadata.outlier
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# Send this event on behalf of the other server.
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#
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# The remote server isn't a full participant in the room at this point, so
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# may not have an up-to-date list of the other homeservers participating in
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# the room, so we send it on their behalf.
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event.internal_metadata.send_on_behalf_of = origin
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context = await self._state_handler.compute_event_context(event)
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context = await self._check_event_auth(origin, event, context)
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if context.rejected:
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raise SynapseError(
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403, f"{event.membership} event was rejected", Codes.FORBIDDEN
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)
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# for joins, we need to check the restrictions of restricted rooms
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if event.membership == Membership.JOIN:
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await self.check_join_restrictions(context, event)
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# for knock events, we run the third-party event rules. It's not entirely clear
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# why we don't do this for other sorts of membership events.
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if event.membership == Membership.KNOCK:
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event_allowed, _ = await self._third_party_event_rules.check_event_allowed(
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event, context
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)
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if not event_allowed:
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logger.info("Sending of knock %s forbidden by third-party rules", event)
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raise SynapseError(
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403, "This event is not allowed in this context", Codes.FORBIDDEN
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)
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# all looks good, we can persist the event.
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# First, precalculate the joined hosts so that the federation sender doesn't
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# need to.
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await self._event_creation_handler.cache_joined_hosts_for_event(event, context)
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await self._run_push_actions_and_persist_event(event, context)
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return event, context
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async def check_join_restrictions(
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self, context: EventContext, event: EventBase
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) -> None:
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"""Check that restrictions in restricted join rules are matched
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Called when we receive a join event via send_join.
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Raises an auth error if the restrictions are not matched.
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"""
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prev_state_ids = await context.get_prev_state_ids()
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# Check if the user is already in the room or invited to the room.
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user_id = event.state_key
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prev_member_event_id = prev_state_ids.get((EventTypes.Member, user_id), None)
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prev_member_event = None
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if prev_member_event_id:
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prev_member_event = await self._store.get_event(prev_member_event_id)
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# Check if the member should be allowed access via membership in a space.
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await self._event_auth_handler.check_restricted_join_rules(
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prev_state_ids,
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event.room_version,
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user_id,
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prev_member_event,
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)
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async def process_remote_join(
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self,
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origin: str,
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room_id: str,
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auth_events: List[EventBase],
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state: List[EventBase],
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event: EventBase,
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room_version: RoomVersion,
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) -> int:
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"""Persists the events returned by a send_join
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Checks the auth chain is valid (and passes auth checks) for the
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state and event. Then persists the auth chain and state atomically.
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Persists the event separately. Notifies about the persisted events
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where appropriate.
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Will attempt to fetch missing auth events.
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Args:
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origin: Where the events came from
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room_id,
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auth_events
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state
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event
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room_version: The room version we expect this room to have, and
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will raise if it doesn't match the version in the create event.
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"""
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events_to_context = {}
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for e in itertools.chain(auth_events, state):
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e.internal_metadata.outlier = True
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events_to_context[e.event_id] = EventContext.for_outlier()
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event_map = {
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e.event_id: e for e in itertools.chain(auth_events, state, [event])
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}
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create_event = None
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for e in auth_events:
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if (e.type, e.state_key) == (EventTypes.Create, ""):
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create_event = e
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break
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if create_event is None:
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# If the state doesn't have a create event then the room is
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# invalid, and it would fail auth checks anyway.
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raise SynapseError(400, "No create event in state")
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room_version_id = create_event.content.get(
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"room_version", RoomVersions.V1.identifier
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)
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if room_version.identifier != room_version_id:
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raise SynapseError(400, "Room version mismatch")
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missing_auth_events = set()
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for e in itertools.chain(auth_events, state, [event]):
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for e_id in e.auth_event_ids():
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if e_id not in event_map:
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missing_auth_events.add(e_id)
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for e_id in missing_auth_events:
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m_ev = await self._federation_client.get_pdu(
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[origin],
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e_id,
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room_version=room_version,
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outlier=True,
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timeout=10000,
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)
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if m_ev and m_ev.event_id == e_id:
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event_map[e_id] = m_ev
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else:
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logger.info("Failed to find auth event %r", e_id)
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for e in itertools.chain(auth_events, state, [event]):
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auth_for_e = [
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event_map[e_id] for e_id in e.auth_event_ids() if e_id in event_map
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]
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if create_event:
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auth_for_e.append(create_event)
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try:
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validate_event_for_room_version(room_version, e)
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check_auth_rules_for_event(room_version, e, auth_for_e)
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except SynapseError as err:
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# we may get SynapseErrors here as well as AuthErrors. For
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# instance, there are a couple of (ancient) events in some
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# rooms whose senders do not have the correct sigil; these
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# cause SynapseErrors in auth.check. We don't want to give up
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# the attempt to federate altogether in such cases.
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logger.warning("Rejecting %s because %s", e.event_id, err.msg)
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if e == event:
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raise
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events_to_context[e.event_id].rejected = RejectedReason.AUTH_ERROR
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if auth_events or state:
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await self.persist_events_and_notify(
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room_id,
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[
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(e, events_to_context[e.event_id])
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for e in itertools.chain(auth_events, state)
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],
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)
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new_event_context = await self._state_handler.compute_event_context(
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event, old_state=state
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)
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return await self.persist_events_and_notify(
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room_id, [(event, new_event_context)]
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)
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@log_function
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async def backfill(
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self, dest: str, room_id: str, limit: int, extremities: Iterable[str]
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) -> 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, event_ids=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 non-outlier event.
|
|
|
|
This is called when we have a new event to add to the room DAG - either directly
|
|
via a /send request, retrieved via get_missing_events after a /send request, or
|
|
backfilled after a client request.
|
|
|
|
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)
|
|
assert not event.internal_metadata.outlier
|
|
|
|
try:
|
|
context = await self._state_handler.compute_event_context(
|
|
event, old_state=state
|
|
)
|
|
context = await self._check_event_auth(
|
|
origin,
|
|
event,
|
|
context,
|
|
state=state,
|
|
backfilled=backfilled,
|
|
)
|
|
except AuthError as e:
|
|
# FIXME richvdh 2021/10/07 I don't think this is reachable. Let's log it
|
|
# for now
|
|
logger.exception("Unexpected AuthError from _check_event_auth")
|
|
raise FederationError("ERROR", e.code, e.msg, affected=event.event_id)
|
|
|
|
await self._run_push_actions_and_persist_event(event, context, backfilled)
|
|
|
|
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.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) -> None:
|
|
"""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 or the event is not from the room creator.
|
|
room_version = await self._store.get_room_version(marker_event.room_id)
|
|
create_event = await self._store.get_create_event_for_room(marker_event.room_id)
|
|
room_creator = create_event.content.get(EventContentFields.ROOM_CREATOR)
|
|
if not room_version.msc2716_historical and (
|
|
not self._config.experimental.msc2716_enabled
|
|
or marker_event.sender != room_creator
|
|
):
|
|
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, event_ids: Collection[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 `event_ids` 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)
|
|
|
|
events: List[EventBase] = []
|
|
|
|
async def get_event(event_id: str) -> None:
|
|
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
|
|
events.append(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, event_ids, 5)
|
|
logger.info("Fetched %i events of %i requested", len(events), len(event_ids))
|
|
await self._auth_and_persist_outliers(room_id, events)
|
|
|
|
async def _auth_and_persist_outliers(
|
|
self, room_id: str, events: Iterable[EventBase]
|
|
) -> None:
|
|
"""Persist a batch of outlier events fetched from remote servers.
|
|
|
|
We first sort the events to make sure that we process each event's auth_events
|
|
before the event itself, and then auth and persist them.
|
|
|
|
Notifies about the events where appropriate.
|
|
|
|
Params:
|
|
room_id: the room that the events are meant to be in (though this has
|
|
not yet been checked)
|
|
events: the events that have been fetched
|
|
"""
|
|
event_map = {event.event_id: event for event in events}
|
|
|
|
# XXX: it might be possible to kick this process off in parallel with fetching
|
|
# the events.
|
|
while event_map:
|
|
# build a list of events whose auth events are not in the queue.
|
|
roots = tuple(
|
|
ev
|
|
for ev in event_map.values()
|
|
if not any(aid in event_map for aid in ev.auth_event_ids())
|
|
)
|
|
|
|
if not roots:
|
|
# if *none* of the remaining events are ready, that means
|
|
# we have a loop. This either means a bug in our logic, or that
|
|
# somebody has managed to create a loop (which requires finding a
|
|
# hash collision in room v2 and later).
|
|
logger.warning(
|
|
"Loop found in auth events while fetching missing state/auth "
|
|
"events: %s",
|
|
shortstr(event_map.keys()),
|
|
)
|
|
return
|
|
|
|
logger.info(
|
|
"Persisting %i of %i remaining outliers: %s",
|
|
len(roots),
|
|
len(event_map),
|
|
shortstr(e.event_id for e in roots),
|
|
)
|
|
|
|
await self._auth_and_persist_outliers_inner(room_id, roots)
|
|
|
|
for ev in roots:
|
|
del event_map[ev.event_id]
|
|
|
|
async def _auth_and_persist_outliers_inner(
|
|
self, room_id: str, fetched_events: Collection[EventBase]
|
|
) -> None:
|
|
"""Helper for _auth_and_persist_outliers
|
|
|
|
Persists a batch of events where we have (theoretically) already persisted all
|
|
of their auth events.
|
|
|
|
Notifies about the events where appropriate.
|
|
|
|
Params:
|
|
origin: where the events came from
|
|
room_id: the room that the events are meant to be in (though this has
|
|
not yet been checked)
|
|
fetched_events: the events to persist
|
|
"""
|
|
# get all the auth events for all the events in this batch. By now, they should
|
|
# have been persisted.
|
|
auth_events = {
|
|
aid for event in fetched_events for aid in event.auth_event_ids()
|
|
}
|
|
persisted_events = await self._store.get_events(
|
|
auth_events,
|
|
allow_rejected=True,
|
|
)
|
|
|
|
room_version = await self._store.get_room_version_id(room_id)
|
|
room_version_obj = KNOWN_ROOM_VERSIONS[room_version]
|
|
|
|
def prep(event: EventBase) -> Optional[Tuple[EventBase, EventContext]]:
|
|
with nested_logging_context(suffix=event.event_id):
|
|
auth = []
|
|
for auth_event_id in event.auth_event_ids():
|
|
ae = persisted_events.get(auth_event_id)
|
|
if not ae:
|
|
logger.warning(
|
|
"Event %s relies on auth_event %s, which could not be found.",
|
|
event,
|
|
auth_event_id,
|
|
)
|
|
# the fact we can't find the auth event doesn't mean it doesn't
|
|
# exist, which means it is premature to reject `event`. Instead we
|
|
# just ignore it for now.
|
|
return None
|
|
auth.append(ae)
|
|
|
|
context = EventContext.for_outlier()
|
|
try:
|
|
validate_event_for_room_version(room_version_obj, event)
|
|
check_auth_rules_for_event(room_version_obj, event, auth)
|
|
except AuthError as e:
|
|
logger.warning("Rejecting %r because %s", event, e)
|
|
context.rejected = RejectedReason.AUTH_ERROR
|
|
|
|
return event, context
|
|
|
|
events_to_persist = (x for x in (prep(event) for event in fetched_events) if x)
|
|
await self.persist_events_and_notify(room_id, tuple(events_to_persist))
|
|
|
|
async def _check_event_auth(
|
|
self,
|
|
origin: str,
|
|
event: EventBase,
|
|
context: EventContext,
|
|
state: Optional[Iterable[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.
|
|
|
|
backfilled: True if the event was backfilled.
|
|
|
|
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`.)
|
|
"""
|
|
# This method should only be used for non-outliers
|
|
assert not event.internal_metadata.outlier
|
|
|
|
# first of all, check that the event itself is valid.
|
|
room_version = await self._store.get_room_version_id(event.room_id)
|
|
room_version_obj = KNOWN_ROOM_VERSIONS[room_version]
|
|
|
|
try:
|
|
validate_event_for_room_version(room_version_obj, event)
|
|
except AuthError as e:
|
|
logger.warning("While validating received event %r: %s", event, e)
|
|
# TODO: use a different rejected reason here?
|
|
context.rejected = RejectedReason.AUTH_ERROR
|
|
return context
|
|
|
|
# next, check that we have all of the event's auth events.
|
|
#
|
|
# Note that this can raise AuthError, which we want to propagate to the
|
|
# caller rather than swallow with `context.rejected` (since we cannot be
|
|
# certain that there is a permanent problem with the event).
|
|
claimed_auth_events = await self._load_or_fetch_auth_events_for_event(
|
|
origin, event
|
|
)
|
|
|
|
# ... and check that the event passes auth at those auth events.
|
|
try:
|
|
check_auth_rules_for_event(room_version_obj, event, claimed_auth_events)
|
|
except AuthError as e:
|
|
logger.warning(
|
|
"While checking auth of %r against auth_events: %s", event, e
|
|
)
|
|
context.rejected = RejectedReason.AUTH_ERROR
|
|
return context
|
|
|
|
# now check auth against what we think the auth events *should* be.
|
|
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)
|
|
calculated_auth_event_map = {
|
|
(e.type, e.state_key): e for e in auth_events_x.values()
|
|
}
|
|
|
|
try:
|
|
updated_auth_events = await self._update_auth_events_for_auth(
|
|
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
|
|
)
|
|
auth_events_for_auth = updated_auth_events
|
|
else:
|
|
auth_events_for_auth = calculated_auth_event_map
|
|
|
|
try:
|
|
check_auth_rules_for_event(
|
|
room_version_obj, 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
|
|
|
|
await self._check_for_soft_fail(event, state, backfilled, origin=origin)
|
|
await self._maybe_kick_guest_users(event)
|
|
|
|
return context
|
|
|
|
async def _maybe_kick_guest_users(self, event: EventBase) -> None:
|
|
if event.type != EventTypes.GuestAccess:
|
|
return
|
|
|
|
guest_access = event.content.get(EventContentFields.GUEST_ACCESS)
|
|
if guest_access == GuestAccess.CAN_JOIN:
|
|
return
|
|
|
|
current_state_map = await self._state_handler.get_current_state(event.room_id)
|
|
current_state = list(current_state_map.values())
|
|
await self._get_room_member_handler().kick_guest_users(current_state)
|
|
|
|
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
|
|
]
|
|
current_auth_events = await self._store.get_events_as_list(
|
|
current_state_ids_list
|
|
)
|
|
|
|
try:
|
|
check_auth_rules_for_event(room_version_obj, event, 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_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]:
|
|
"""Fetch this event's auth_events, from database or remote
|
|
|
|
Loads any of the auth_events that we already have from the database/cache. If
|
|
there are any that are missing, calls /event_auth to get the complete auth
|
|
chain for the event (and then attempts to load the auth_events again).
|
|
|
|
If any of the auth_events cannot be found, raises an AuthError. This can happen
|
|
for a number of reasons; eg: the events don't exist, or we were unable to talk
|
|
to `destination`, or we couldn't validate the signature on the event (which
|
|
in turn has multiple potential causes).
|
|
|
|
Args:
|
|
destination: where to send the /event_auth request. Typically the server
|
|
that sent us `event` in the first place.
|
|
event: the event whose auth_events we want
|
|
|
|
Returns:
|
|
all of the events in `event.auth_events`, after deduplication
|
|
|
|
Raises:
|
|
AuthError if we were unable to fetch the auth_events for any reason.
|
|
"""
|
|
event_auth_event_ids = set(event.auth_event_ids())
|
|
event_auth_events = await self._store.get_events(
|
|
event_auth_event_ids, allow_rejected=True
|
|
)
|
|
missing_auth_event_ids = event_auth_event_ids.difference(
|
|
event_auth_events.keys()
|
|
)
|
|
if not missing_auth_event_ids:
|
|
return event_auth_events.values()
|
|
|
|
logger.info(
|
|
"Event %s refers to unknown auth events %s: fetching auth chain",
|
|
event,
|
|
missing_auth_event_ids,
|
|
)
|
|
try:
|
|
await self._get_remote_auth_chain_for_event(
|
|
destination, event.room_id, event.event_id
|
|
)
|
|
except Exception as e:
|
|
logger.warning("Failed to get auth chain for %s: %s", event, e)
|
|
# in this case, it's very likely we still won't have all the auth
|
|
# events - but we pick that up below.
|
|
|
|
# try to fetch the auth events we missed list time.
|
|
extra_auth_events = await self._store.get_events(
|
|
missing_auth_event_ids, allow_rejected=True
|
|
)
|
|
missing_auth_event_ids.difference_update(extra_auth_events.keys())
|
|
event_auth_events.update(extra_auth_events)
|
|
if not missing_auth_event_ids:
|
|
return event_auth_events.values()
|
|
|
|
# we still don't have all the auth events.
|
|
logger.warning(
|
|
"Missing auth events for %s: %s",
|
|
event,
|
|
shortstr(missing_auth_event_ids),
|
|
)
|
|
# the fact we can't find the auth event doesn't mean it doesn't
|
|
# exist, which means it is premature to store `event` as rejected.
|
|
# instead we raise an AuthError, which will make the caller ignore it.
|
|
raise AuthError(code=HTTPStatus.FORBIDDEN, msg="Auth events could not be found")
|
|
|
|
async def _get_remote_auth_chain_for_event(
|
|
self, destination: str, room_id: str, event_id: str
|
|
) -> None:
|
|
"""If we are missing some of an event's auth events, attempt to request them
|
|
|
|
Args:
|
|
destination: where to fetch the auth tree from
|
|
room_id: the room in which we are lacking auth events
|
|
event_id: the event for which we are lacking auth events
|
|
"""
|
|
try:
|
|
remote_event_map = {
|
|
e.event_id: e
|
|
for e in await self._federation_client.get_event_auth(
|
|
destination, room_id, 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
|
|
|
|
logger.info("/event_auth returned %i events", len(remote_event_map))
|
|
|
|
# `event` may be returned, but we should not yet process it.
|
|
remote_event_map.pop(event_id, None)
|
|
|
|
# nor should we reprocess any events we have already seen.
|
|
seen_remotes = await self._store.have_seen_events(
|
|
room_id, remote_event_map.keys()
|
|
)
|
|
for s in seen_remotes:
|
|
remote_event_map.pop(s, None)
|
|
|
|
await self._auth_and_persist_outliers(room_id, remote_event_map.values())
|
|
|
|
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
|
|
) -> None:
|
|
"""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.
|
|
"""
|
|
# this method should not be called on outliers (those code paths call
|
|
# persist_events_and_notify directly.)
|
|
assert not event.internal_metadata.outlier
|
|
|
|
if not backfilled and not context.rejected:
|
|
min_depth = await self._store.get_min_depth(event.room_id)
|
|
if min_depth is None or min_depth > event.depth:
|
|
# XXX richvdh 2021/10/07: I don't really understand what this
|
|
# condition is doing. I think it's trying not to send pushes
|
|
# for events that predate our join - but that's not really what
|
|
# min_depth means, and anyway ancient events are a more general
|
|
# problem.
|
|
#
|
|
# for now I'm just going to log about it.
|
|
logger.info(
|
|
"Skipping push actions for old event with depth %s < %s",
|
|
event.depth,
|
|
min_depth,
|
|
)
|
|
else:
|
|
await self._action_generator.handle_push_actions_for_event(
|
|
event, context
|
|
)
|
|
|
|
try:
|
|
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")
|