# -*- coding: utf-8 -*- # Copyright 2014 - 2016 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. from twisted.internet import defer from synapse.api.errors import LimitExceededError, SynapseError, AuthError from synapse.crypto.event_signing import add_hashes_and_signatures from synapse.api.constants import Membership, EventTypes from synapse.types import UserID, RoomAlias, Requester, get_domian_from_id from synapse.push.action_generator import ActionGenerator from synapse.util.logcontext import PreserveLoggingContext, preserve_fn import logging logger = logging.getLogger(__name__) VISIBILITY_PRIORITY = ( "world_readable", "shared", "invited", "joined", ) MEMBERSHIP_PRIORITY = ( Membership.JOIN, Membership.INVITE, Membership.KNOCK, Membership.LEAVE, Membership.BAN, ) class BaseHandler(object): """ Common base class for the event handlers. Attributes: store (synapse.storage.events.StateStore): state_handler (synapse.state.StateHandler): """ def __init__(self, hs): self.store = hs.get_datastore() self.auth = hs.get_auth() self.notifier = hs.get_notifier() self.state_handler = hs.get_state_handler() self.distributor = hs.get_distributor() self.ratelimiter = hs.get_ratelimiter() self.clock = hs.get_clock() self.hs = hs self.signing_key = hs.config.signing_key[0] self.server_name = hs.hostname self.event_builder_factory = hs.get_event_builder_factory() @defer.inlineCallbacks def filter_events_for_clients(self, user_tuples, events, event_id_to_state): """ Returns dict of user_id -> list of events that user is allowed to see. Args: user_tuples (str, bool): (user id, is_peeking) for each user to be checked. is_peeking should be true if: * the user is not currently a member of the room, and: * the user has not been a member of the room since the given events events ([synapse.events.EventBase]): list of events to filter """ forgotten = yield defer.gatherResults([ self.store.who_forgot_in_room( room_id, ) for room_id in frozenset(e.room_id for e in events) ], consumeErrors=True) # Set of membership event_ids that have been forgotten event_id_forgotten = frozenset( row["event_id"] for rows in forgotten for row in rows ) def allowed(event, user_id, is_peeking): """ Args: event (synapse.events.EventBase): event to check user_id (str) is_peeking (bool) """ state = event_id_to_state[event.event_id] # get the room_visibility at the time of the event. visibility_event = state.get((EventTypes.RoomHistoryVisibility, ""), None) if visibility_event: visibility = visibility_event.content.get("history_visibility", "shared") else: visibility = "shared" if visibility not in VISIBILITY_PRIORITY: visibility = "shared" # if it was world_readable, it's easy: everyone can read it if visibility == "world_readable": return True # Always allow history visibility events on boundaries. This is done # by setting the effective visibility to the least restrictive # of the old vs new. if event.type == EventTypes.RoomHistoryVisibility: prev_content = event.unsigned.get("prev_content", {}) prev_visibility = prev_content.get("history_visibility", None) if prev_visibility not in VISIBILITY_PRIORITY: prev_visibility = "shared" new_priority = VISIBILITY_PRIORITY.index(visibility) old_priority = VISIBILITY_PRIORITY.index(prev_visibility) if old_priority < new_priority: visibility = prev_visibility # likewise, if the event is the user's own membership event, use # the 'most joined' membership membership = None if event.type == EventTypes.Member and event.state_key == user_id: membership = event.content.get("membership", None) if membership not in MEMBERSHIP_PRIORITY: membership = "leave" prev_content = event.unsigned.get("prev_content", {}) prev_membership = prev_content.get("membership", None) if prev_membership not in MEMBERSHIP_PRIORITY: prev_membership = "leave" new_priority = MEMBERSHIP_PRIORITY.index(membership) old_priority = MEMBERSHIP_PRIORITY.index(prev_membership) if old_priority < new_priority: membership = prev_membership # otherwise, get the user's membership at the time of the event. if membership is None: membership_event = state.get((EventTypes.Member, user_id), None) if membership_event: if membership_event.event_id not in event_id_forgotten: membership = membership_event.membership # if the user was a member of the room at the time of the event, # they can see it. if membership == Membership.JOIN: return True if visibility == "joined": # we weren't a member at the time of the event, so we can't # see this event. return False elif visibility == "invited": # user can also see the event if they were *invited* at the time # of the event. return membership == Membership.INVITE else: # visibility is shared: user can also see the event if they have # become a member since the event # # XXX: if the user has subsequently joined and then left again, # ideally we would share history up to the point they left. But # we don't know when they left. return not is_peeking defer.returnValue({ user_id: [ event for event in events if allowed(event, user_id, is_peeking) ] for user_id, is_peeking in user_tuples }) @defer.inlineCallbacks def filter_events_for_client(self, user_id, events, is_peeking=False): """ Check which events a user is allowed to see Args: user_id(str): user id to be checked events([synapse.events.EventBase]): list of events to be checked is_peeking(bool): should be True if: * the user is not currently a member of the room, and: * the user has not been a member of the room since the given events Returns: [synapse.events.EventBase] """ types = ( (EventTypes.RoomHistoryVisibility, ""), (EventTypes.Member, user_id), ) event_id_to_state = yield self.store.get_state_for_events( frozenset(e.event_id for e in events), types=types ) res = yield self.filter_events_for_clients( [(user_id, is_peeking)], events, event_id_to_state ) defer.returnValue(res.get(user_id, [])) def ratelimit(self, requester): time_now = self.clock.time() allowed, time_allowed = self.ratelimiter.send_message( requester.user.to_string(), time_now, msg_rate_hz=self.hs.config.rc_messages_per_second, burst_count=self.hs.config.rc_message_burst_count, ) if not allowed: raise LimitExceededError( retry_after_ms=int(1000 * (time_allowed - time_now)), ) @defer.inlineCallbacks def _create_new_client_event(self, builder, prev_event_ids=None): if prev_event_ids: prev_events = yield self.store.add_event_hashes(prev_event_ids) prev_max_depth = yield self.store.get_max_depth_of_events(prev_event_ids) depth = prev_max_depth + 1 else: latest_ret = yield self.store.get_latest_event_ids_and_hashes_in_room( builder.room_id, ) if latest_ret: depth = max([d for _, _, d in latest_ret]) + 1 else: depth = 1 prev_events = [ (event_id, prev_hashes) for event_id, prev_hashes, _ in latest_ret ] builder.prev_events = prev_events builder.depth = depth state_handler = self.state_handler context = yield state_handler.compute_event_context(builder) if builder.is_state(): builder.prev_state = yield self.store.add_event_hashes( context.prev_state_events ) yield self.auth.add_auth_events(builder, context) add_hashes_and_signatures( builder, self.server_name, self.signing_key ) event = builder.build() logger.debug( "Created event %s with current state: %s", event.event_id, context.current_state, ) defer.returnValue( (event, context,) ) def is_host_in_room(self, current_state): room_members = [ (state_key, event.membership) for ((event_type, state_key), event) in current_state.items() if event_type == EventTypes.Member ] if len(room_members) == 0: # Have we just created the room, and is this about to be the very # first member event? create_event = current_state.get(("m.room.create", "")) if create_event: return True for (state_key, membership) in room_members: if ( self.hs.is_mine_id(state_key) and membership == Membership.JOIN ): return True return False @defer.inlineCallbacks def handle_new_client_event( self, requester, event, context, ratelimit=True, extra_users=[] ): # We now need to go and hit out to wherever we need to hit out to. if ratelimit: self.ratelimit(requester) try: self.auth.check(event, auth_events=context.current_state) except AuthError as err: logger.warn("Denying new event %r because %s", event, err) raise err yield self.maybe_kick_guest_users(event, context.current_state.values()) if event.type == EventTypes.CanonicalAlias: # Check the alias is acually valid (at this time at least) room_alias_str = event.content.get("alias", None) if room_alias_str: room_alias = RoomAlias.from_string(room_alias_str) directory_handler = self.hs.get_handlers().directory_handler mapping = yield directory_handler.get_association(room_alias) if mapping["room_id"] != event.room_id: raise SynapseError( 400, "Room alias %s does not point to the room" % ( room_alias_str, ) ) federation_handler = self.hs.get_handlers().federation_handler if event.type == EventTypes.Member: if event.content["membership"] == Membership.INVITE: def is_inviter_member_event(e): return ( e.type == EventTypes.Member and e.sender == event.sender ) event.unsigned["invite_room_state"] = [ { "type": e.type, "state_key": e.state_key, "content": e.content, "sender": e.sender, } for k, e in context.current_state.items() if e.type in self.hs.config.room_invite_state_types or is_inviter_member_event(e) ] invitee = UserID.from_string(event.state_key) if not self.hs.is_mine(invitee): # TODO: Can we add signature from remote server in a nicer # way? If we have been invited by a remote server, we need # to get them to sign the event. returned_invite = yield federation_handler.send_invite( invitee.domain, event, ) event.unsigned.pop("room_state", None) # TODO: Make sure the signatures actually are correct. event.signatures.update( returned_invite.signatures ) if event.type == EventTypes.Redaction: if self.auth.check_redaction(event, auth_events=context.current_state): original_event = yield self.store.get_event( event.redacts, check_redacted=False, get_prev_content=False, allow_rejected=False, allow_none=False ) if event.user_id != original_event.user_id: raise AuthError( 403, "You don't have permission to redact events" ) if event.type == EventTypes.Create and context.current_state: raise AuthError( 403, "Changing the room create event is forbidden", ) action_generator = ActionGenerator(self.hs) yield action_generator.handle_push_actions_for_event( event, context, self ) (event_stream_id, max_stream_id) = yield self.store.persist_event( event, context=context ) # this intentionally does not yield: we don't care about the result # and don't need to wait for it. preserve_fn(self.hs.get_pusherpool().on_new_notifications)( event_stream_id, max_stream_id ) destinations = set() for k, s in context.current_state.items(): try: if k[0] == EventTypes.Member: if s.content["membership"] == Membership.JOIN: destinations.add(get_domian_from_id(s.state_key)) except SynapseError: logger.warn( "Failed to get destination from event %s", s.event_id ) with PreserveLoggingContext(): # Don't block waiting on waking up all the listeners. self.notifier.on_new_room_event( event, event_stream_id, max_stream_id, extra_users=extra_users ) # If invite, remove room_state from unsigned before sending. event.unsigned.pop("invite_room_state", None) federation_handler.handle_new_event( event, destinations=destinations, ) @defer.inlineCallbacks def maybe_kick_guest_users(self, event, current_state): # Technically this function invalidates current_state by changing it. # Hopefully this isn't that important to the caller. if event.type == EventTypes.GuestAccess: guest_access = event.content.get("guest_access", "forbidden") if guest_access != "can_join": yield self.kick_guest_users(current_state) @defer.inlineCallbacks def kick_guest_users(self, current_state): for member_event in current_state: try: if member_event.type != EventTypes.Member: continue target_user = UserID.from_string(member_event.state_key) if not self.hs.is_mine(target_user): continue if member_event.content["membership"] not in { Membership.JOIN, Membership.INVITE }: continue if ( "kind" not in member_event.content or member_event.content["kind"] != "guest" ): continue # We make the user choose to leave, rather than have the # event-sender kick them. This is partially because we don't # need to worry about power levels, and partially because guest # users are a concept which doesn't hugely work over federation, # and having homeservers have their own users leave keeps more # of that decision-making and control local to the guest-having # homeserver. requester = Requester(target_user, "", True) handler = self.hs.get_handlers().room_member_handler yield handler.update_membership( requester, target_user, member_event.room_id, "leave", ratelimit=False, ) except Exception as e: logger.warn("Error kicking guest user: %s" % (e,))