185 lines
7.5 KiB
Python
185 lines
7.5 KiB
Python
# Copyright 2014 - 2016 OpenMarket Ltd
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import logging
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from typing import TYPE_CHECKING, Optional
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import synapse.state
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import synapse.storage
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import synapse.types
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from synapse.api.constants import EventTypes, Membership
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from synapse.api.ratelimiting import Ratelimiter
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from synapse.types import UserID
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if TYPE_CHECKING:
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from synapse.server import HomeServer
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logger = logging.getLogger(__name__)
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class BaseHandler:
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"""
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Common base class for the event handlers.
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Deprecated: new code should not use this. Instead, Handler classes should define the
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fields they actually need. The utility methods should either be factored out to
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standalone helper functions, or to different Handler classes.
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"""
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def __init__(self, hs: "HomeServer"):
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self.store = hs.get_datastore() # type: synapse.storage.DataStore
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self.auth = hs.get_auth()
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self.notifier = hs.get_notifier()
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self.state_handler = hs.get_state_handler() # type: synapse.state.StateHandler
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self.distributor = hs.get_distributor()
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self.clock = hs.get_clock()
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self.hs = hs
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# The rate_hz and burst_count are overridden on a per-user basis
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self.request_ratelimiter = Ratelimiter(
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store=self.store, clock=self.clock, rate_hz=0, burst_count=0
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)
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self._rc_message = self.hs.config.rc_message
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# Check whether ratelimiting room admin message redaction is enabled
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# by the presence of rate limits in the config
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if self.hs.config.rc_admin_redaction:
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self.admin_redaction_ratelimiter = Ratelimiter(
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store=self.store,
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clock=self.clock,
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rate_hz=self.hs.config.rc_admin_redaction.per_second,
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burst_count=self.hs.config.rc_admin_redaction.burst_count,
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) # type: Optional[Ratelimiter]
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else:
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self.admin_redaction_ratelimiter = None
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self.server_name = hs.hostname
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self.event_builder_factory = hs.get_event_builder_factory()
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async def ratelimit(self, requester, update=True, is_admin_redaction=False):
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"""Ratelimits requests.
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Args:
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requester (Requester)
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update (bool): Whether to record that a request is being processed.
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Set to False when doing multiple checks for one request (e.g.
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to check up front if we would reject the request), and set to
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True for the last call for a given request.
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is_admin_redaction (bool): Whether this is a room admin/moderator
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redacting an event. If so then we may apply different
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ratelimits depending on config.
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Raises:
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LimitExceededError if the request should be ratelimited
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"""
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user_id = requester.user.to_string()
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# The AS user itself is never rate limited.
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app_service = self.store.get_app_service_by_user_id(user_id)
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if app_service is not None:
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return # do not ratelimit app service senders
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messages_per_second = self._rc_message.per_second
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burst_count = self._rc_message.burst_count
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# Check if there is a per user override in the DB.
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override = await self.store.get_ratelimit_for_user(user_id)
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if override:
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# If overridden with a null Hz then ratelimiting has been entirely
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# disabled for the user
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if not override.messages_per_second:
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return
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messages_per_second = override.messages_per_second
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burst_count = override.burst_count
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if is_admin_redaction and self.admin_redaction_ratelimiter:
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# If we have separate config for admin redactions, use a separate
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# ratelimiter as to not have user_ids clash
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await self.admin_redaction_ratelimiter.ratelimit(requester, update=update)
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else:
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# Override rate and burst count per-user
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await self.request_ratelimiter.ratelimit(
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requester,
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rate_hz=messages_per_second,
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burst_count=burst_count,
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update=update,
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)
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async def maybe_kick_guest_users(self, event, context=None):
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# Technically this function invalidates current_state by changing it.
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# Hopefully this isn't that important to the caller.
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if event.type == EventTypes.GuestAccess:
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guest_access = event.content.get("guest_access", "forbidden")
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if guest_access != "can_join":
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if context:
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current_state_ids = await context.get_current_state_ids()
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current_state_dict = await self.store.get_events(
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list(current_state_ids.values())
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)
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current_state = list(current_state_dict.values())
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else:
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current_state_map = await self.state_handler.get_current_state(
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event.room_id
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)
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current_state = list(current_state_map.values())
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logger.info("maybe_kick_guest_users %r", current_state)
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await self.kick_guest_users(current_state)
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async def kick_guest_users(self, current_state):
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for member_event in current_state:
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try:
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if member_event.type != EventTypes.Member:
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continue
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target_user = UserID.from_string(member_event.state_key)
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if not self.hs.is_mine(target_user):
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continue
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if member_event.content["membership"] not in {
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Membership.JOIN,
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Membership.INVITE,
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}:
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continue
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if (
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"kind" not in member_event.content
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or member_event.content["kind"] != "guest"
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):
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continue
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# We make the user choose to leave, rather than have the
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# event-sender kick them. This is partially because we don't
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# need to worry about power levels, and partially because guest
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# users are a concept which doesn't hugely work over federation,
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# and having homeservers have their own users leave keeps more
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# of that decision-making and control local to the guest-having
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# homeserver.
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requester = synapse.types.create_requester(
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target_user, is_guest=True, authenticated_entity=self.server_name
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)
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handler = self.hs.get_room_member_handler()
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await handler.update_membership(
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requester,
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target_user,
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member_event.room_id,
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"leave",
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ratelimit=False,
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require_consent=False,
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)
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except Exception as e:
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logger.exception("Error kicking guest user: %s" % (e,))
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