# -*- coding: utf-8 -*- # Copyright 2014, 2015 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.errors import ( AuthError, FederationError, StoreError, ) from synapse.api.constants import EventTypes, Membership, RejectedReason from synapse.util.logutils import log_function from synapse.util.async import run_on_reactor from synapse.util.frozenutils import unfreeze from synapse.crypto.event_signing import ( compute_event_signature, add_hashes_and_signatures, ) from synapse.types import UserID from twisted.internet import defer import itertools 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, destinations): """ 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: The event to send destinations: A list of destinations to send it to Returns: Deferred: Resolved when it has successfully been queued for processing. """ yield run_on_reactor() self.replication_layer.send_pdu(event, destinations) @log_function @defer.inlineCallbacks def on_receive_pdu(self, origin, pdu, backfilled, state=None, auth_chain=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) 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.internal_metadata.is_outlier(): logger.debug("Got event for room we're not in.") current_state = state event_ids = set() if state: event_ids |= {e.event_id for e in state} if auth_chain: event_ids |= {e.event_id for e in auth_chain} seen_ids = set( (yield self.store.have_events(event_ids)).keys() ) if state and auth_chain is not None: # If we have any state or auth_chain given to us by the replication # layer, then we should handle them (if we haven't before.) for e in itertools.chain(auth_chain, state): if e.event_id in seen_ids: continue e.internal_metadata.outlier = True try: auth_ids = [e_id for e_id, _ in e.auth_events] auth = { (e.type, e.state_key): e for e in auth_chain if e.event_id in auth_ids } yield self._handle_new_event( origin, e, auth_events=auth ) seen_ids.add(e.event_id) except: logger.exception( "Failed to handle state event %s", e.event_id, ) try: yield self._handle_new_event( origin, event, state=state, backfilled=backfilled, current_state=current_state, ) except AuthError as e: raise FederationError( "ERROR", e.code, e.msg, affected=event.event_id, ) # if we're receiving valid events from an origin, # it's probably a good idea to mark it as not in retry-state # for sending (although this is a bit of a leap) retry_timings = yield self.store.get_destination_retry_timings(origin) if (retry_timings and retry_timings.retry_last_ts): self.store.set_destination_retry_timings(origin, 0, 0) 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 == EventTypes.Member: target_user_id = event.state_key target_user = UserID.from_string(target_user_id) extra_users.append(target_user) yield self.notifier.on_new_room_event( event, extra_users=extra_users ) if event.type == EventTypes.Member: if event.membership == Membership.JOIN: user = UserID.from_string(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 :/ context = yield self.state_handler.compute_event_context(event) events.append((event, context)) yield self.store.persist_event( event, context=context, 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, room_id=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_hosts, 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) origin, pdu = yield self.replication_layer.make_join( target_hosts, room_id, joinee ) logger.debug("Got response to make_join: %s", pdu) event = pdu # We should assert some things. # FIXME: Do this in a nicer way assert(event.type == EventTypes.Member) assert(event.user_id == joinee) assert(event.state_key == joinee) assert(event.room_id == room_id) event.internal_metadata.outlier = False self.room_queues[room_id] = [] builder = self.event_builder_factory.new( unfreeze(event.get_pdu_json()) ) handled_events = set() try: builder.event_id = self.event_builder_factory.create_event_id() builder.origin = self.hs.hostname builder.content = content if not hasattr(event, "signatures"): builder.signatures = {} add_hashes_and_signatures( builder, self.hs.hostname, self.hs.config.signing_key[0], ) new_event = builder.build() # Try the host we successfully got a response to /make_join/ # request first. try: target_hosts.remove(origin) target_hosts.insert(0, origin) except ValueError: pass ret = yield self.replication_layer.send_join( target_hosts, new_event ) origin = ret["origin"] state = ret["state"] auth_chain = ret["auth_chain"] auth_chain.sort(key=lambda e: e.depth) handled_events.update([s.event_id for s in state]) handled_events.update([a.event_id for a in auth_chain]) handled_events.add(new_event.event_id) 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", new_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.internal_metadata.outlier = True if e.event_id == event.event_id: continue try: auth_ids = [e_id for e_id, _ in e.auth_events] auth = { (e.type, e.state_key): e for e in auth_chain if e.event_id in auth_ids } yield self._handle_new_event( origin, e, auth_events=auth ) except: logger.exception( "Failed to handle auth event %s", e.event_id, ) for e in state: if e.event_id == event.event_id: continue e.internal_metadata.outlier = True try: auth_ids = [e_id for e_id, _ in e.auth_events] auth = { (e.type, e.state_key): e for e in auth_chain if e.event_id in auth_ids } yield self._handle_new_event( origin, e, auth_events=auth ) except: logger.exception( "Failed to handle state event %s", e.event_id, ) auth_ids = [e_id for e_id, _ in event.auth_events] auth_events = { (e.type, e.state_key): e for e in auth_chain if e.event_id in auth_ids } yield self._handle_new_event( origin, new_event, state=state, current_state=state, auth_events=auth_events, ) yield self.notifier.on_new_room_event( new_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: if p.event_id in handled_events: continue 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, room_id, 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. """ builder = self.event_builder_factory.new({ "type": EventTypes.Member, "content": {"membership": Membership.JOIN}, "room_id": room_id, "sender": user_id, "state_key": user_id, }) event, context = yield self._create_new_client_event( builder=builder, ) self.auth.check(event, auth_events=context.auth_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 logger.debug( "on_send_join_request: Got event: %s, signatures: %s", event.event_id, event.signatures, ) event.internal_metadata.outlier = False context = yield self._handle_new_event(origin, event) logger.debug( "on_send_join_request: After _handle_new_event: %s, sigs: %s", event.event_id, event.signatures, ) extra_users = [] if event.type == EventTypes.Member: target_user_id = event.state_key target_user = UserID.from_string(target_user_id) extra_users.append(target_user) yield self.notifier.on_new_room_event( event, extra_users=extra_users ) if event.type == EventTypes.Member: if event.content["membership"] == Membership.JOIN: user = UserID.from_string(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 context.current_state.items(): try: if k[0] == EventTypes.Member: if s.content["membership"] == Membership.JOIN: destinations.add( UserID.from_string(s.state_key).domain ) except: logger.warn( "Failed to get destination from event %s", s.event_id ) destinations.discard(origin) logger.debug( "on_send_join_request: Sending event: %s, signatures: %s", event.event_id, event.signatures, ) self.replication_layer.send_pdu(new_pdu, destinations) state_ids = [e.event_id for e in context.current_state.values()] auth_chain = yield self.store.get_auth_chain(set( [event.event_id] + state_ids )) defer.returnValue({ "state": context.current_state.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.internal_metadata.outlier = True event.signatures.update( compute_event_signature( event, self.hs.hostname, self.hs.config.signing_key[0] ) ) context = yield self.state_handler.compute_event_context(event) yield self.store.persist_event( event, context=context, backfilled=False, ) target_user = UserID.from_string(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 event and event.is_state(): # Get previous state if "replaces_state" in event.unsigned: prev_id = event.unsigned["replaces_state"] if prev_id != event.event_id: prev_event = yield self.store.get_event(prev_id) 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, room_id, pdu_list, limit): in_room = yield self.auth.check_host_in_room(room_id, origin) if not in_room: raise AuthError(403, "Host not in room.") events = yield self.store.get_backfill_events( room_id, 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, allow_rejected=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 @log_function def _handle_new_event(self, origin, event, state=None, backfilled=False, current_state=None, auth_events=None): logger.debug( "_handle_new_event: %s, sigs: %s", event.event_id, event.signatures, ) context = yield self.state_handler.compute_event_context( event, old_state=state ) if not auth_events: auth_events = context.auth_events logger.debug( "_handle_new_event: %s, auth_events: %s", event.event_id, auth_events, ) is_new_state = not event.internal_metadata.is_outlier() # This is a hack to fix some old rooms where the initial join event # didn't reference the create event in its auth events. if event.type == EventTypes.Member 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 == EventTypes.Create: auth_events[(c.type, c.state_key)] = c try: yield self.do_auth( origin, event, context, auth_events=auth_events ) except AuthError as e: logger.warn( "Rejecting %s because %s", event.event_id, e.msg ) context.rejected = RejectedReason.AUTH_ERROR # FIXME: Don't store as rejected with AUTH_ERROR if we haven't # seen all the auth events. yield self.store.persist_event( event, context=context, backfilled=backfilled, is_new_state=False, current_state=current_state, ) raise yield self.store.persist_event( event, context=context, backfilled=backfilled, is_new_state=(is_new_state and not backfilled), current_state=current_state, ) defer.returnValue(context) @defer.inlineCallbacks def on_query_auth(self, origin, event_id, remote_auth_chain, rejects, missing): # Just go through and process each event in `remote_auth_chain`. We # don't want to fall into the trap of `missing` being wrong. for e in remote_auth_chain: try: yield self._handle_new_event(origin, e) except AuthError: pass # Now get the current auth_chain for the event. local_auth_chain = yield self.store.get_auth_chain([event_id]) # TODO: Check if we would now reject event_id. If so we need to tell # everyone. ret = yield self.construct_auth_difference( local_auth_chain, remote_auth_chain ) for event in ret["auth_chain"]: event.signatures.update( compute_event_signature( event, self.hs.hostname, self.hs.config.signing_key[0] ) ) logger.debug("on_query_auth returning: %s", ret) defer.returnValue(ret) @defer.inlineCallbacks @log_function def do_auth(self, origin, event, context, auth_events): # Check if we have all the auth events. have_events = yield self.store.have_events( [e_id for e_id, _ in event.auth_events] ) event_auth_events = set(e_id for e_id, _ in event.auth_events) seen_events = set(have_events.keys()) missing_auth = event_auth_events - seen_events if missing_auth: logger.info("Missing auth: %s", missing_auth) # If we don't have all the auth events, we need to get them. try: remote_auth_chain = yield self.replication_layer.get_event_auth( origin, event.room_id, event.event_id ) seen_remotes = yield self.store.have_events( [e.event_id for e in remote_auth_chain] ) for e in remote_auth_chain: if e.event_id in seen_remotes.keys(): continue if e.event_id == event.event_id: continue try: auth_ids = [e_id for e_id, _ in e.auth_events] auth = { (e.type, e.state_key): e for e in remote_auth_chain if e.event_id in auth_ids } e.internal_metadata.outlier = True logger.debug( "do_auth %s missing_auth: %s", event.event_id, e.event_id ) yield self._handle_new_event( origin, e, auth_events=auth ) if e.event_id in event_auth_events: auth_events[(e.type, e.state_key)] = e except AuthError: pass have_events = yield self.store.have_events( [e_id for e_id, _ in event.auth_events] ) seen_events = set(have_events.keys()) except: # FIXME: logger.exception("Failed to get auth chain") # FIXME: Assumes we have and stored all the state for all the # prev_events current_state = set(e.event_id for e in auth_events.values()) different_auth = event_auth_events - current_state if different_auth and not event.internal_metadata.is_outlier(): # Do auth conflict res. logger.info("Different auth: %s", different_auth) different_events = yield defer.gatherResults( [ self.store.get_event( d, allow_none=True, allow_rejected=False, ) for d in different_auth if d in have_events and not have_events[d] ], consumeErrors=True ) if different_events: local_view = dict(auth_events) remote_view = dict(auth_events) remote_view.update({ (d.type, d.state_key) for d in different_events }) new_state, prev_state = self.state_handler.resolve_events( [local_view.values(), remote_view.values()], event ) auth_events.update(new_state) current_state = set(e.event_id for e in auth_events.values()) different_auth = event_auth_events - current_state context.current_state.update(auth_events) context.state_group = None if different_auth and not event.internal_metadata.is_outlier(): logger.info("Different auth after resolution: %s", different_auth) # Only do auth resolution if we have something new to say. # We can't rove an auth failure. do_resolution = False provable = [ RejectedReason.NOT_ANCESTOR, RejectedReason.NOT_ANCESTOR, ] for e_id in different_auth: if e_id in have_events: if have_events[e_id] in provable: do_resolution = True break if do_resolution: # 1. Get what we think is the auth chain. auth_ids = self.auth.compute_auth_events( event, context.current_state ) local_auth_chain = yield self.store.get_auth_chain(auth_ids) try: # 2. Get remote difference. result = yield self.replication_layer.query_auth( origin, event.room_id, event.event_id, local_auth_chain, ) seen_remotes = yield self.store.have_events( [e.event_id for e in result["auth_chain"]] ) # 3. Process any remote auth chain events we haven't seen. for ev in result["auth_chain"]: if ev.event_id in seen_remotes.keys(): continue if ev.event_id == event.event_id: continue try: auth_ids = [e_id for e_id, _ in ev.auth_events] auth = { (e.type, e.state_key): e for e in result["auth_chain"] if e.event_id in auth_ids } ev.internal_metadata.outlier = True logger.debug( "do_auth %s different_auth: %s", event.event_id, e.event_id ) yield self._handle_new_event( origin, ev, auth_events=auth ) if ev.event_id in event_auth_events: auth_events[(ev.type, ev.state_key)] = ev except AuthError: pass except: # FIXME: logger.exception("Failed to query auth chain") # 4. Look at rejects and their proofs. # TODO. context.current_state.update(auth_events) context.state_group = None try: self.auth.check(event, auth_events=auth_events) except AuthError: raise @defer.inlineCallbacks def construct_auth_difference(self, local_auth, remote_auth): """ Given a local and remote auth chain, find the differences. This assumes that we have already processed all events in remote_auth Params: local_auth (list) remote_auth (list) Returns: dict """ logger.debug("construct_auth_difference Start!") # TODO: Make sure we are OK with local_auth or remote_auth having more # auth events in them than strictly necessary. def sort_fun(ev): return ev.depth, ev.event_id logger.debug("construct_auth_difference after sort_fun!") # We find the differences by starting at the "bottom" of each list # and iterating up on both lists. The lists are ordered by depth and # then event_id, we iterate up both lists until we find the event ids # don't match. Then we look at depth/event_id to see which side is # missing that event, and iterate only up that list. Repeat. remote_list = list(remote_auth) remote_list.sort(key=sort_fun) local_list = list(local_auth) local_list.sort(key=sort_fun) local_iter = iter(local_list) remote_iter = iter(remote_list) logger.debug("construct_auth_difference before get_next!") def get_next(it, opt=None): try: return it.next() except: return opt current_local = get_next(local_iter) current_remote = get_next(remote_iter) logger.debug("construct_auth_difference before while") missing_remotes = [] missing_locals = [] while current_local or current_remote: if current_remote is None: missing_locals.append(current_local) current_local = get_next(local_iter) continue if current_local is None: missing_remotes.append(current_remote) current_remote = get_next(remote_iter) continue if current_local.event_id == current_remote.event_id: current_local = get_next(local_iter) current_remote = get_next(remote_iter) continue if current_local.depth < current_remote.depth: missing_locals.append(current_local) current_local = get_next(local_iter) continue if current_local.depth > current_remote.depth: missing_remotes.append(current_remote) current_remote = get_next(remote_iter) continue # They have the same depth, so we fall back to the event_id order if current_local.event_id < current_remote.event_id: missing_locals.append(current_local) current_local = get_next(local_iter) if current_local.event_id > current_remote.event_id: missing_remotes.append(current_remote) current_remote = get_next(remote_iter) continue logger.debug("construct_auth_difference after while") # missing locals should be sent to the server # We should find why we are missing remotes, as they will have been # rejected. # Remove events from missing_remotes if they are referencing a missing # remote. We only care about the "root" rejected ones. missing_remote_ids = [e.event_id for e in missing_remotes] base_remote_rejected = list(missing_remotes) for e in missing_remotes: for e_id, _ in e.auth_events: if e_id in missing_remote_ids: try: base_remote_rejected.remove(e) except ValueError: pass reason_map = {} for e in base_remote_rejected: reason = yield self.store.get_rejection_reason(e.event_id) if reason is None: # TODO: e is not in the current state, so we should # construct some proof of that. continue reason_map[e.event_id] = reason if reason == RejectedReason.AUTH_ERROR: pass elif reason == RejectedReason.REPLACED: # TODO: Get proof pass elif reason == RejectedReason.NOT_ANCESTOR: # TODO: Get proof. pass logger.debug("construct_auth_difference returning") defer.returnValue({ "auth_chain": local_auth, "rejects": { e.event_id: { "reason": reason_map[e.event_id], "proof": None, } for e in base_remote_rejected }, "missing": [e.event_id for e in missing_locals], })