# -*- 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 from synapse.api.constants import Membership, EventTypes from synapse.types import UserID, Requester from synapse.util.logcontext import 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.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([ preserve_fn(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 ) ignore_dict_content = yield self.store.get_global_account_data_by_type_for_users( "m.ignored_user_list", user_ids=[user_id for user_id, _ in user_tuples] ) # FIXME: This will explode if people upload something incorrect. ignore_dict = { user_id: frozenset( content.get("ignored_users", {}).keys() if content else [] ) for user_id, content in ignore_dict_content.items() } def allowed(event, user_id, is_peeking, ignore_list): """ Args: event (synapse.events.EventBase): event to check user_id (str) is_peeking (bool) ignore_list (list): list of users to ignore """ if not event.is_state() and event.sender in ignore_list: return False 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, ignore_dict.get(user_id, [])) ] 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)), ) 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 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,))