162 lines
5.2 KiB
Python
162 lines
5.2 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright 2019 The Matrix.org Foundation C.I.C.
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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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from typing import Callable
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from synapse.events import EventBase
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from synapse.events.snapshot import EventContext
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from synapse.types import Requester, StateMap
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class ThirdPartyEventRules:
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"""Allows server admins to provide a Python module implementing an extra
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set of rules to apply when processing events.
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This is designed to help admins of closed federations with enforcing custom
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behaviours.
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"""
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def __init__(self, hs):
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self.third_party_rules = None
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self.store = hs.get_datastore()
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module = None
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config = None
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if hs.config.third_party_event_rules:
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module, config = hs.config.third_party_event_rules
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if module is not None:
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self.third_party_rules = module(
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config=config, module_api=hs.get_module_api(),
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)
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async def check_event_allowed(
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self, event: EventBase, context: EventContext
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) -> bool:
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"""Check if a provided event should be allowed in the given context.
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Args:
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event: The event to be checked.
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context: The context of the event.
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Returns:
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True if the event should be allowed, False if not.
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"""
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if self.third_party_rules is None:
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return True
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prev_state_ids = await context.get_prev_state_ids()
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# Retrieve the state events from the database.
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events = await self.store.get_events(prev_state_ids.values())
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state_events = {(ev.type, ev.state_key): ev for ev in events.values()}
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# The module can modify the event slightly if it wants, but caution should be
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# exercised, and it's likely to go very wrong if applied to events received over
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# federation.
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return await self.third_party_rules.check_event_allowed(event, state_events)
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async def on_create_room(
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self, requester: Requester, config: dict, is_requester_admin: bool
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) -> bool:
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"""Intercept requests to create room to allow, deny or update the
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request config.
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Args:
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requester
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config: The creation config from the client.
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is_requester_admin: If the requester is an admin
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Returns:
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Whether room creation is allowed or denied.
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"""
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if self.third_party_rules is None:
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return True
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ret = await self.third_party_rules.on_create_room(
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requester, config, is_requester_admin
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)
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return ret
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async def check_threepid_can_be_invited(
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self, medium: str, address: str, room_id: str
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) -> bool:
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"""Check if a provided 3PID can be invited in the given room.
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Args:
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medium: The 3PID's medium.
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address: The 3PID's address.
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room_id: The room we want to invite the threepid to.
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Returns:
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True if the 3PID can be invited, False if not.
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"""
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if self.third_party_rules is None:
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return True
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state_events = await self._get_state_map_for_room(room_id)
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ret = await self.third_party_rules.check_threepid_can_be_invited(
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medium, address, state_events
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)
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return ret
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async def check_visibility_can_be_modified(
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self, room_id: str, new_visibility: str
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) -> bool:
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"""Check if a room is allowed to be published to, or removed from, the public room
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list.
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Args:
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room_id: The ID of the room.
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new_visibility: The new visibility state. Either "public" or "private".
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Returns:
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True if the room's visibility can be modified, False if not.
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"""
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if self.third_party_rules is None:
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return True
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check_func = getattr(
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self.third_party_rules, "check_visibility_can_be_modified", None
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)
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if not check_func or not isinstance(check_func, Callable):
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return True
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state_events = await self._get_state_map_for_room(room_id)
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return await check_func(room_id, state_events, new_visibility)
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async def _get_state_map_for_room(self, room_id: str) -> StateMap[EventBase]:
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"""Given a room ID, return the state events of that room.
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Args:
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room_id: The ID of the room.
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Returns:
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A dict mapping (event type, state key) to state event.
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"""
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state_ids = await self.store.get_filtered_current_state_ids(room_id)
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room_state_events = await self.store.get_events(state_ids.values())
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state_events = {}
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for key, event_id in state_ids.items():
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state_events[key] = room_state_events[event_id]
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return state_events
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