# -*- coding: utf-8 -*- # Copyright 2014 OpenMarket Ltd # # 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. """Contains handlers for federation events.""" from ._base import BaseHandler from synapse.api.events.utils import prune_event from synapse.api.errors import ( AuthError, FederationError, SynapseError, StoreError, ) from synapse.api.events.room import RoomMemberEvent, RoomCreateEvent from synapse.api.constants import Membership from synapse.util.logutils import log_function from synapse.util.async import run_on_reactor from synapse.crypto.event_signing import ( compute_event_signature, check_event_content_hash, add_hashes_and_signatures, ) from syutil.jsonutil import encode_canonical_json from twisted.internet import defer import logging logger = logging.getLogger(__name__) class FederationHandler(BaseHandler): """Handles events that originated from federation. Responsible for: a) handling received Pdus before handing them on as Events to the rest of the home server (including auth and state conflict resoultion) b) converting events that were produced by local clients that may need to be sent to remote home servers. c) doing the necessary dances to invite remote users and join remote rooms. """ def __init__(self, hs): super(FederationHandler, self).__init__(hs) self.distributor.observe( "user_joined_room", self._on_user_joined ) self.waiting_for_join_list = {} self.store = hs.get_datastore() self.replication_layer = hs.get_replication_layer() self.state_handler = hs.get_state_handler() # self.auth_handler = gs.get_auth_handler() self.server_name = hs.hostname self.keyring = hs.get_keyring() self.lock_manager = hs.get_room_lock_manager() self.replication_layer.set_handler(self) # When joining a room we need to queue any events for that room up self.room_queues = {} @log_function @defer.inlineCallbacks def handle_new_event(self, event, snapshot): """ Takes in an event from the client to server side, that has already been authed and handled by the state module, and sends it to any remote home servers that may be interested. Args: event snapshot (.storage.Snapshot): THe snapshot the event happened after Returns: Deferred: Resolved when it has successfully been queued for processing. """ yield run_on_reactor() pdu = event if not hasattr(pdu, "destinations") or not pdu.destinations: pdu.destinations = [] yield self.replication_layer.send_pdu(pdu) @log_function @defer.inlineCallbacks def on_receive_pdu(self, origin, pdu, backfilled, state=None): """ Called by the ReplicationLayer when we have a new pdu. We need to do auth checks and put it through the StateHandler. """ event = pdu logger.debug("Got event: %s", event.event_id) # If we are currently in the process of joining this room, then we # queue up events for later processing. if event.room_id in self.room_queues: self.room_queues[event.room_id].append((pdu, origin)) return logger.debug("Processing event: %s", event.event_id) redacted_event = prune_event(event) redacted_pdu_json = redacted_event.get_pdu_json() try: yield self.keyring.verify_json_for_server( event.origin, redacted_pdu_json ) except SynapseError as e: logger.warn( "Signature check failed for %s redacted to %s", encode_canonical_json(pdu.get_pdu_json()), encode_canonical_json(redacted_pdu_json), ) raise FederationError( "ERROR", e.code, e.msg, affected=event.event_id, ) if not check_event_content_hash(event): logger.warn( "Event content has been tampered, redacting %s, %s", event.event_id, encode_canonical_json(event.get_full_dict()) ) event = redacted_event logger.debug("Event: %s", event) # FIXME (erikj): Awful hack to make the case where we are not currently # in the room work current_state = None is_in_room = yield self.auth.check_host_in_room( event.room_id, self.server_name ) if not is_in_room and not event.outlier: logger.debug("Got event for room we're not in.") replication_layer = self.replication_layer auth_chain = yield replication_layer.get_event_auth( origin, context=event.room_id, event_id=event.event_id, ) for e in auth_chain: e.outlier = True try: yield self._handle_new_event(e, fetch_missing=False) except: logger.exception( "Failed to parse auth event %s", e.event_id, ) if not state: state = yield replication_layer.get_state_for_context( origin, context=event.room_id, event_id=event.event_id, ) current_state = state if state: for e in state: e.outlier = True try: yield self._handle_new_event(e) except: logger.exception( "Failed to parse state event %s", e.event_id, ) try: yield self._handle_new_event( event, state=state, backfilled=backfilled, current_state=current_state, ) except AuthError as e: raise FederationError( "ERROR", e.code, e.msg, affected=event.event_id, ) room = yield self.store.get_room(event.room_id) if not room: try: yield self.store.store_room( room_id=event.room_id, room_creator_user_id="", is_public=False, ) except StoreError: logger.exception("Failed to store room.") if not backfilled: extra_users = [] if event.type == RoomMemberEvent.TYPE: target_user_id = event.state_key target_user = self.hs.parse_userid(target_user_id) extra_users.append(target_user) yield self.notifier.on_new_room_event( event, extra_users=extra_users ) if event.type == RoomMemberEvent.TYPE: if event.membership == Membership.JOIN: user = self.hs.parse_userid(event.state_key) yield self.distributor.fire( "user_joined_room", user=user, room_id=event.room_id ) @log_function @defer.inlineCallbacks def backfill(self, dest, room_id, limit): """ Trigger a backfill request to `dest` for the given `room_id` """ extremities = yield self.store.get_oldest_events_in_room(room_id) pdus = yield self.replication_layer.backfill( dest, room_id, limit, extremities=extremities, ) events = [] for pdu in pdus: event = pdu # FIXME (erikj): Not sure this actually works :/ yield self.state_handler.annotate_event_with_state(event) events.append(event) yield self.store.persist_event(event, backfilled=True) defer.returnValue(events) @defer.inlineCallbacks def send_invite(self, target_host, event): """ Sends the invite to the remote server for signing. Invites must be signed by the invitee's server before distribution. """ pdu = yield self.replication_layer.send_invite( destination=target_host, context=event.room_id, event_id=event.event_id, pdu=event ) defer.returnValue(pdu) @defer.inlineCallbacks def on_event_auth(self, event_id): auth = yield self.store.get_auth_chain(event_id) for event in auth: event.signatures.update( compute_event_signature( event, self.hs.hostname, self.hs.config.signing_key[0] ) ) defer.returnValue([e for e in auth]) @log_function @defer.inlineCallbacks def do_invite_join(self, target_host, room_id, joinee, content, snapshot): """ Attempts to join the `joinee` to the room `room_id` via the server `target_host`. This first triggers a /make_join/ request that returns a partial event that we can fill out and sign. This is then sent to the remote server via /send_join/ which responds with the state at that event and the auth_chains. We suspend processing of any received events from this room until we have finished processing the join. """ logger.debug("Joining %s to %s", joinee, room_id) pdu = yield self.replication_layer.make_join( target_host, room_id, joinee ) logger.debug("Got response to make_join: %s", pdu) event = pdu # We should assert some things. assert(event.type == RoomMemberEvent.TYPE) assert(event.user_id == joinee) assert(event.state_key == joinee) assert(event.room_id == room_id) event.outlier = False self.room_queues[room_id] = [] try: event.event_id = self.event_factory.create_event_id() event.origin = self.hs.hostname event.content = content if not hasattr(event, "signatures"): event.signatures = {} add_hashes_and_signatures( event, self.hs.hostname, self.hs.config.signing_key[0], ) ret = yield self.replication_layer.send_join( target_host, event ) state = ret["state"] auth_chain = ret["auth_chain"] auth_chain.sort(key=lambda e: e.depth) logger.debug("do_invite_join auth_chain: %s", auth_chain) logger.debug("do_invite_join state: %s", state) logger.debug("do_invite_join event: %s", event) try: yield self.store.store_room( room_id=room_id, room_creator_user_id="", is_public=False ) except: # FIXME pass for e in auth_chain: e.outlier = True try: yield self._handle_new_event(e, fetch_missing=False) except: logger.exception( "Failed to parse auth event %s", e.event_id, ) for e in state: # FIXME: Auth these. e.outlier = True try: yield self._handle_new_event( e, fetch_missing=True ) except: logger.exception( "Failed to parse state event %s", e.event_id, ) yield self._handle_new_event( event, state=state, current_state=state, ) yield self.notifier.on_new_room_event( event, extra_users=[joinee] ) logger.debug("Finished joining %s to %s", joinee, room_id) finally: room_queue = self.room_queues[room_id] del self.room_queues[room_id] for p, origin in room_queue: try: self.on_receive_pdu(origin, p, backfilled=False) except: logger.exception("Couldn't handle pdu") defer.returnValue(True) @defer.inlineCallbacks @log_function def on_make_join_request(self, context, user_id): """ We've received a /make_join/ request, so we create a partial join event for the room and return that. We don *not* persist or process it until the other server has signed it and sent it back. """ event = self.event_factory.create_event( etype=RoomMemberEvent.TYPE, content={"membership": Membership.JOIN}, room_id=context, user_id=user_id, state_key=user_id, ) snapshot = yield self.store.snapshot_room(event) snapshot.fill_out_prev_events(event) yield self.state_handler.annotate_event_with_state(event) yield self.auth.add_auth_events(event) self.auth.check(event, auth_events=event.old_state_events) pdu = event defer.returnValue(pdu) @defer.inlineCallbacks @log_function def on_send_join_request(self, origin, pdu): """ We have received a join event for a room. Fully process it and respond with the current state and auth chains. """ event = pdu event.outlier = False yield self._handle_new_event(event) extra_users = [] if event.type == RoomMemberEvent.TYPE: target_user_id = event.state_key target_user = self.hs.parse_userid(target_user_id) extra_users.append(target_user) yield self.notifier.on_new_room_event( event, extra_users=extra_users ) if event.type == RoomMemberEvent.TYPE: if event.content["membership"] == Membership.JOIN: user = self.hs.parse_userid(event.state_key) yield self.distributor.fire( "user_joined_room", user=user, room_id=event.room_id ) new_pdu = event destinations = set() for k, s in event.state_events.items(): try: if k[0] == RoomMemberEvent.TYPE: if s.content["membership"] == Membership.JOIN: destinations.add( self.hs.parse_userid(s.state_key).domain ) except: logger.warn( "Failed to get destination from event %s", s.event_id ) new_pdu.destinations = list(destinations) yield self.replication_layer.send_pdu(new_pdu) auth_chain = yield self.store.get_auth_chain(event.event_id) defer.returnValue({ "state": event.state_events.values(), "auth_chain": auth_chain, }) @defer.inlineCallbacks def on_invite_request(self, origin, pdu): """ We've got an invite event. Process and persist it. Sign it. Respond with the now signed event. """ event = pdu event.outlier = True event.signatures.update( compute_event_signature( event, self.hs.hostname, self.hs.config.signing_key[0] ) ) yield self.state_handler.annotate_event_with_state(event) yield self.store.persist_event( event, backfilled=False, ) target_user = self.hs.parse_userid(event.state_key) yield self.notifier.on_new_room_event( event, extra_users=[target_user], ) defer.returnValue(event) @defer.inlineCallbacks def get_state_for_pdu(self, origin, room_id, event_id): yield run_on_reactor() in_room = yield self.auth.check_host_in_room(room_id, origin) if not in_room: raise AuthError(403, "Host not in room.") state_groups = yield self.store.get_state_groups( [event_id] ) if state_groups: _, state = state_groups.items().pop() results = { (e.type, e.state_key): e for e in state } event = yield self.store.get_event(event_id) if hasattr(event, "state_key"): # Get previous state if hasattr(event, "replaces_state") and event.replaces_state: prev_event = yield self.store.get_event( event.replaces_state ) results[(event.type, event.state_key)] = prev_event else: del results[(event.type, event.state_key)] res = results.values() for event in res: event.signatures.update( compute_event_signature( event, self.hs.hostname, self.hs.config.signing_key[0] ) ) defer.returnValue(res) else: defer.returnValue([]) @defer.inlineCallbacks @log_function def on_backfill_request(self, origin, context, pdu_list, limit): in_room = yield self.auth.check_host_in_room(context, origin) if not in_room: raise AuthError(403, "Host not in room.") events = yield self.store.get_backfill_events( context, pdu_list, limit ) defer.returnValue(events) @defer.inlineCallbacks @log_function def get_persisted_pdu(self, origin, event_id, do_auth=True): """ Get a PDU from the database with given origin and id. Returns: Deferred: Results in a `Pdu`. """ event = yield self.store.get_event( event_id, allow_none=True, ) if event: # FIXME: This is a temporary work around where we occasionally # return events slightly differently than when they were # originally signed event.signatures.update( compute_event_signature( event, self.hs.hostname, self.hs.config.signing_key[0] ) ) if do_auth: in_room = yield self.auth.check_host_in_room( event.room_id, origin ) if not in_room: raise AuthError(403, "Host not in room.") defer.returnValue(event) else: defer.returnValue(None) @log_function def get_min_depth_for_context(self, context): return self.store.get_min_depth(context) @log_function def _on_user_joined(self, user, room_id): waiters = self.waiting_for_join_list.get( (user.to_string(), room_id), [] ) while waiters: waiters.pop().callback(None) @defer.inlineCallbacks def _handle_new_event(self, event, state=None, backfilled=False, current_state=None, fetch_missing=True): is_new_state = yield self.state_handler.annotate_event_with_state( event, old_state=state ) if event.old_state_events: known_ids = set( [s.event_id for s in event.old_state_events.values()] ) for e_id, _ in event.auth_events: if e_id not in known_ids: e = yield self.store.get_event( e_id, allow_none=True, ) if not e: # TODO: Do some conflict res to make sure that we're # not the ones who are wrong. logger.info( "Rejecting %s as %s not in %s", event.event_id, e_id, known_ids, ) raise AuthError(403, "Auth events are stale") auth_events = event.old_state_events else: # We need to get the auth events from somewhere. # TODO: Don't just hit the DBs? auth_events = {} for e_id, _ in event.auth_events: e = yield self.store.get_event( e_id, allow_none=True, ) if not e: e = yield self.replication_layer.get_pdu( event.origin, e_id, outlier=True ) if e and fetch_missing: try: yield self.on_receive_pdu(event.origin, e, False) except: logger.exception( "Failed to parse auth event %s", e_id, ) if not e: logger.warn("Can't find auth event %s.", e_id) auth_events[(e.type, e.state_key)] = e if event.type == RoomMemberEvent.TYPE and not event.auth_events: if len(event.prev_events) == 1: c = yield self.store.get_event(event.prev_events[0][0]) if c.type == RoomCreateEvent.TYPE: auth_events[(c.type, c.state_key)] = c self.auth.check(event, auth_events=auth_events) yield self.store.persist_event( event, backfilled=backfilled, is_new_state=(is_new_state and not backfilled), current_state=current_state, )