159 lines
		
	
	
		
			5.1 KiB
		
	
	
	
		
			Python
		
	
	
			
		
		
	
	
			159 lines
		
	
	
		
			5.1 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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| 
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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.module_api import ModuleApi
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| from synapse.types import Requester, StateMap
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| 
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| 
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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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| 
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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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| 
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|     def __init__(self, hs):
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|         self.third_party_rules = None
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| 
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|         self.store = hs.get_datastore()
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| 
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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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| 
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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=ModuleApi(hs, hs.get_auth_handler()),
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|             )
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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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| 
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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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| 
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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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| 
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|         prev_state_ids = await context.get_prev_state_ids()
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| 
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|         # Retrieve the state events from the database.
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|         state_events = {}
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|         for key, event_id in prev_state_ids.items():
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|             state_events[key] = await self.store.get_event(event_id, allow_none=True)
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| 
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|         ret = await self.third_party_rules.check_event_allowed(event, state_events)
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|         return ret
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| 
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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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| 
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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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| 
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|         Returns:
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|             Whether room creation is allowed or denied.
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|         """
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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|         if self.third_party_rules is None:
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|             return True
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| 
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|         state_events = await self._get_state_map_for_room(room_id)
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| 
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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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| 
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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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| 
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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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| 
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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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| 
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|         check_func = getattr(self.third_party_rules, "check_visibility_can_be_modified")
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|         if not check_func or not isinstance(check_func, Callable):
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|             return True
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| 
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|         state_events = await self._get_state_map_for_room(room_id)
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| 
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|         return await check_func(room_id, state_events, new_visibility)
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| 
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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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| 
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|         Args:
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|             room_id: The ID of the room.
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| 
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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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| 
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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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| 
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|         return state_events
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