# -*- 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. import logging from typing import TYPE_CHECKING, Optional import synapse.state import synapse.storage import synapse.types from synapse.api.constants import EventTypes, Membership from synapse.api.ratelimiting import Ratelimiter from synapse.types import UserID if TYPE_CHECKING: from synapse.server import HomeServer logger = logging.getLogger(__name__) class BaseHandler: """ Common base class for the event handlers. Deprecated: new code should not use this. Instead, Handler classes should define the fields they actually need. The utility methods should either be factored out to standalone helper functions, or to different Handler classes. """ def __init__(self, hs: "HomeServer"): self.store = hs.get_datastore() # type: synapse.storage.DataStore self.auth = hs.get_auth() self.notifier = hs.get_notifier() self.state_handler = hs.get_state_handler() # type: synapse.state.StateHandler self.distributor = hs.get_distributor() self.clock = hs.get_clock() self.hs = hs # The rate_hz and burst_count are overridden on a per-user basis self.request_ratelimiter = Ratelimiter( store=self.store, clock=self.clock, rate_hz=0, burst_count=0 ) self._rc_message = self.hs.config.rc_message # Check whether ratelimiting room admin message redaction is enabled # by the presence of rate limits in the config if self.hs.config.rc_admin_redaction: self.admin_redaction_ratelimiter = Ratelimiter( store=self.store, clock=self.clock, rate_hz=self.hs.config.rc_admin_redaction.per_second, burst_count=self.hs.config.rc_admin_redaction.burst_count, ) # type: Optional[Ratelimiter] else: self.admin_redaction_ratelimiter = None self.server_name = hs.hostname self.event_builder_factory = hs.get_event_builder_factory() async def ratelimit(self, requester, update=True, is_admin_redaction=False): """Ratelimits requests. Args: requester (Requester) update (bool): Whether to record that a request is being processed. Set to False when doing multiple checks for one request (e.g. to check up front if we would reject the request), and set to True for the last call for a given request. is_admin_redaction (bool): Whether this is a room admin/moderator redacting an event. If so then we may apply different ratelimits depending on config. Raises: LimitExceededError if the request should be ratelimited """ user_id = requester.user.to_string() # The AS user itself is never rate limited. app_service = self.store.get_app_service_by_user_id(user_id) if app_service is not None: return # do not ratelimit app service senders messages_per_second = self._rc_message.per_second burst_count = self._rc_message.burst_count # Check if there is a per user override in the DB. override = await self.store.get_ratelimit_for_user(user_id) if override: # If overridden with a null Hz then ratelimiting has been entirely # disabled for the user if not override.messages_per_second: return messages_per_second = override.messages_per_second burst_count = override.burst_count if is_admin_redaction and self.admin_redaction_ratelimiter: # If we have separate config for admin redactions, use a separate # ratelimiter as to not have user_ids clash await self.admin_redaction_ratelimiter.ratelimit(requester, update=update) else: # Override rate and burst count per-user await self.request_ratelimiter.ratelimit( requester, rate_hz=messages_per_second, burst_count=burst_count, update=update, ) async def maybe_kick_guest_users(self, event, context=None): # 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": if context: current_state_ids = await context.get_current_state_ids() current_state_dict = await self.store.get_events( list(current_state_ids.values()) ) current_state = list(current_state_dict.values()) else: current_state_map = await self.state_handler.get_current_state( event.room_id ) current_state = list(current_state_map.values()) logger.info("maybe_kick_guest_users %r", current_state) await self.kick_guest_users(current_state) async 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 = synapse.types.create_requester( target_user, is_guest=True, authenticated_entity=self.server_name ) handler = self.hs.get_room_member_handler() await handler.update_membership( requester, target_user, member_event.room_id, "leave", ratelimit=False, require_consent=False, ) except Exception as e: logger.exception("Error kicking guest user: %s" % (e,))