331 lines
12 KiB
Python
331 lines
12 KiB
Python
# Copyright 2019 The Matrix.org Foundation C.I.C.
|
|
#
|
|
# 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, Awaitable, Callable, List, Optional, Tuple
|
|
|
|
from synapse.api.errors import SynapseError
|
|
from synapse.events import EventBase
|
|
from synapse.events.snapshot import EventContext
|
|
from synapse.types import Requester, StateMap
|
|
from synapse.util.async_helpers import maybe_awaitable
|
|
|
|
if TYPE_CHECKING:
|
|
from synapse.server import HomeServer
|
|
|
|
logger = logging.getLogger(__name__)
|
|
|
|
|
|
CHECK_EVENT_ALLOWED_CALLBACK = Callable[
|
|
[EventBase, StateMap[EventBase]], Awaitable[Tuple[bool, Optional[dict]]]
|
|
]
|
|
ON_CREATE_ROOM_CALLBACK = Callable[[Requester, dict, bool], Awaitable]
|
|
CHECK_THREEPID_CAN_BE_INVITED_CALLBACK = Callable[
|
|
[str, str, StateMap[EventBase]], Awaitable[bool]
|
|
]
|
|
CHECK_VISIBILITY_CAN_BE_MODIFIED_CALLBACK = Callable[
|
|
[str, StateMap[EventBase], str], Awaitable[bool]
|
|
]
|
|
|
|
|
|
def load_legacy_third_party_event_rules(hs: "HomeServer"):
|
|
"""Wrapper that loads a third party event rules module configured using the old
|
|
configuration, and registers the hooks they implement.
|
|
"""
|
|
if hs.config.third_party_event_rules is None:
|
|
return
|
|
|
|
module, config = hs.config.third_party_event_rules
|
|
|
|
api = hs.get_module_api()
|
|
third_party_rules = module(config=config, module_api=api)
|
|
|
|
# The known hooks. If a module implements a method which name appears in this set,
|
|
# we'll want to register it.
|
|
third_party_event_rules_methods = {
|
|
"check_event_allowed",
|
|
"on_create_room",
|
|
"check_threepid_can_be_invited",
|
|
"check_visibility_can_be_modified",
|
|
}
|
|
|
|
def async_wrapper(f: Optional[Callable]) -> Optional[Callable[..., Awaitable]]:
|
|
# f might be None if the callback isn't implemented by the module. In this
|
|
# case we don't want to register a callback at all so we return None.
|
|
if f is None:
|
|
return None
|
|
|
|
# We return a separate wrapper for these methods because, in order to wrap them
|
|
# correctly, we need to await its result. Therefore it doesn't make a lot of
|
|
# sense to make it go through the run() wrapper.
|
|
if f.__name__ == "check_event_allowed":
|
|
|
|
# We need to wrap check_event_allowed because its old form would return either
|
|
# a boolean or a dict, but now we want to return the dict separately from the
|
|
# boolean.
|
|
async def wrap_check_event_allowed(
|
|
event: EventBase,
|
|
state_events: StateMap[EventBase],
|
|
) -> Tuple[bool, Optional[dict]]:
|
|
# We've already made sure f is not None above, but mypy doesn't do well
|
|
# across function boundaries so we need to tell it f is definitely not
|
|
# None.
|
|
assert f is not None
|
|
|
|
res = await f(event, state_events)
|
|
if isinstance(res, dict):
|
|
return True, res
|
|
else:
|
|
return res, None
|
|
|
|
return wrap_check_event_allowed
|
|
|
|
if f.__name__ == "on_create_room":
|
|
|
|
# We need to wrap on_create_room because its old form would return a boolean
|
|
# if the room creation is denied, but now we just want it to raise an
|
|
# exception.
|
|
async def wrap_on_create_room(
|
|
requester: Requester, config: dict, is_requester_admin: bool
|
|
) -> None:
|
|
# We've already made sure f is not None above, but mypy doesn't do well
|
|
# across function boundaries so we need to tell it f is definitely not
|
|
# None.
|
|
assert f is not None
|
|
|
|
res = await f(requester, config, is_requester_admin)
|
|
if res is False:
|
|
raise SynapseError(
|
|
403,
|
|
"Room creation forbidden with these parameters",
|
|
)
|
|
|
|
return wrap_on_create_room
|
|
|
|
def run(*args, **kwargs):
|
|
# mypy doesn't do well across function boundaries so we need to tell it
|
|
# f is definitely not None.
|
|
assert f is not None
|
|
|
|
return maybe_awaitable(f(*args, **kwargs))
|
|
|
|
return run
|
|
|
|
# Register the hooks through the module API.
|
|
hooks = {
|
|
hook: async_wrapper(getattr(third_party_rules, hook, None))
|
|
for hook in third_party_event_rules_methods
|
|
}
|
|
|
|
api.register_third_party_rules_callbacks(**hooks)
|
|
|
|
|
|
class ThirdPartyEventRules:
|
|
"""Allows server admins to provide a Python module implementing an extra
|
|
set of rules to apply when processing events.
|
|
|
|
This is designed to help admins of closed federations with enforcing custom
|
|
behaviours.
|
|
"""
|
|
|
|
def __init__(self, hs: "HomeServer"):
|
|
self.third_party_rules = None
|
|
|
|
self.store = hs.get_datastore()
|
|
|
|
self._check_event_allowed_callbacks: List[CHECK_EVENT_ALLOWED_CALLBACK] = []
|
|
self._on_create_room_callbacks: List[ON_CREATE_ROOM_CALLBACK] = []
|
|
self._check_threepid_can_be_invited_callbacks: List[
|
|
CHECK_THREEPID_CAN_BE_INVITED_CALLBACK
|
|
] = []
|
|
self._check_visibility_can_be_modified_callbacks: List[
|
|
CHECK_VISIBILITY_CAN_BE_MODIFIED_CALLBACK
|
|
] = []
|
|
|
|
def register_third_party_rules_callbacks(
|
|
self,
|
|
check_event_allowed: Optional[CHECK_EVENT_ALLOWED_CALLBACK] = None,
|
|
on_create_room: Optional[ON_CREATE_ROOM_CALLBACK] = None,
|
|
check_threepid_can_be_invited: Optional[
|
|
CHECK_THREEPID_CAN_BE_INVITED_CALLBACK
|
|
] = None,
|
|
check_visibility_can_be_modified: Optional[
|
|
CHECK_VISIBILITY_CAN_BE_MODIFIED_CALLBACK
|
|
] = None,
|
|
):
|
|
"""Register callbacks from modules for each hook."""
|
|
if check_event_allowed is not None:
|
|
self._check_event_allowed_callbacks.append(check_event_allowed)
|
|
|
|
if on_create_room is not None:
|
|
self._on_create_room_callbacks.append(on_create_room)
|
|
|
|
if check_threepid_can_be_invited is not None:
|
|
self._check_threepid_can_be_invited_callbacks.append(
|
|
check_threepid_can_be_invited,
|
|
)
|
|
|
|
if check_visibility_can_be_modified is not None:
|
|
self._check_visibility_can_be_modified_callbacks.append(
|
|
check_visibility_can_be_modified,
|
|
)
|
|
|
|
async def check_event_allowed(
|
|
self, event: EventBase, context: EventContext
|
|
) -> Tuple[bool, Optional[dict]]:
|
|
"""Check if a provided event should be allowed in the given context.
|
|
|
|
The module can return:
|
|
* True: the event is allowed.
|
|
* False: the event is not allowed, and should be rejected with M_FORBIDDEN.
|
|
|
|
If the event is allowed, the module can also return a dictionary to use as a
|
|
replacement for the event.
|
|
|
|
Args:
|
|
event: The event to be checked.
|
|
context: The context of the event.
|
|
|
|
Returns:
|
|
The result from the ThirdPartyRules module, as above.
|
|
"""
|
|
# Bail out early without hitting the store if we don't have any callbacks to run.
|
|
if len(self._check_event_allowed_callbacks) == 0:
|
|
return True, None
|
|
|
|
prev_state_ids = await context.get_prev_state_ids()
|
|
|
|
# Retrieve the state events from the database.
|
|
events = await self.store.get_events(prev_state_ids.values())
|
|
state_events = {(ev.type, ev.state_key): ev for ev in events.values()}
|
|
|
|
# Ensure that the event is frozen, to make sure that the module is not tempted
|
|
# to try to modify it. Any attempt to modify it at this point will invalidate
|
|
# the hashes and signatures.
|
|
event.freeze()
|
|
|
|
for callback in self._check_event_allowed_callbacks:
|
|
try:
|
|
res, replacement_data = await callback(event, state_events)
|
|
except Exception as e:
|
|
logger.warning("Failed to run module API callback %s: %s", callback, e)
|
|
continue
|
|
|
|
# Return if the event shouldn't be allowed or if the module came up with a
|
|
# replacement dict for the event.
|
|
if res is False:
|
|
return res, None
|
|
elif isinstance(replacement_data, dict):
|
|
return True, replacement_data
|
|
|
|
return True, None
|
|
|
|
async def on_create_room(
|
|
self, requester: Requester, config: dict, is_requester_admin: bool
|
|
) -> None:
|
|
"""Intercept requests to create room to maybe deny it (via an exception) or
|
|
update the request config.
|
|
|
|
Args:
|
|
requester
|
|
config: The creation config from the client.
|
|
is_requester_admin: If the requester is an admin
|
|
"""
|
|
for callback in self._on_create_room_callbacks:
|
|
try:
|
|
await callback(requester, config, is_requester_admin)
|
|
except Exception as e:
|
|
# Don't silence the errors raised by this callback since we expect it to
|
|
# raise an exception to deny the creation of the room; instead make sure
|
|
# it's a SynapseError we can send to clients.
|
|
if not isinstance(e, SynapseError):
|
|
e = SynapseError(
|
|
403, "Room creation forbidden with these parameters"
|
|
)
|
|
|
|
raise e
|
|
|
|
async def check_threepid_can_be_invited(
|
|
self, medium: str, address: str, room_id: str
|
|
) -> bool:
|
|
"""Check if a provided 3PID can be invited in the given room.
|
|
|
|
Args:
|
|
medium: The 3PID's medium.
|
|
address: The 3PID's address.
|
|
room_id: The room we want to invite the threepid to.
|
|
|
|
Returns:
|
|
True if the 3PID can be invited, False if not.
|
|
"""
|
|
# Bail out early without hitting the store if we don't have any callbacks to run.
|
|
if len(self._check_threepid_can_be_invited_callbacks) == 0:
|
|
return True
|
|
|
|
state_events = await self._get_state_map_for_room(room_id)
|
|
|
|
for callback in self._check_threepid_can_be_invited_callbacks:
|
|
try:
|
|
if await callback(medium, address, state_events) is False:
|
|
return False
|
|
except Exception as e:
|
|
logger.warning("Failed to run module API callback %s: %s", callback, e)
|
|
|
|
return True
|
|
|
|
async def check_visibility_can_be_modified(
|
|
self, room_id: str, new_visibility: str
|
|
) -> bool:
|
|
"""Check if a room is allowed to be published to, or removed from, the public room
|
|
list.
|
|
|
|
Args:
|
|
room_id: The ID of the room.
|
|
new_visibility: The new visibility state. Either "public" or "private".
|
|
|
|
Returns:
|
|
True if the room's visibility can be modified, False if not.
|
|
"""
|
|
# Bail out early without hitting the store if we don't have any callback
|
|
if len(self._check_visibility_can_be_modified_callbacks) == 0:
|
|
return True
|
|
|
|
state_events = await self._get_state_map_for_room(room_id)
|
|
|
|
for callback in self._check_visibility_can_be_modified_callbacks:
|
|
try:
|
|
if await callback(room_id, state_events, new_visibility) is False:
|
|
return False
|
|
except Exception as e:
|
|
logger.warning("Failed to run module API callback %s: %s", callback, e)
|
|
|
|
return True
|
|
|
|
async def _get_state_map_for_room(self, room_id: str) -> StateMap[EventBase]:
|
|
"""Given a room ID, return the state events of that room.
|
|
|
|
Args:
|
|
room_id: The ID of the room.
|
|
|
|
Returns:
|
|
A dict mapping (event type, state key) to state event.
|
|
"""
|
|
state_ids = await self.store.get_filtered_current_state_ids(room_id)
|
|
room_state_events = await self.store.get_events(state_ids.values())
|
|
|
|
state_events = {}
|
|
for key, event_id in state_ids.items():
|
|
state_events[key] = room_state_events[event_id]
|
|
|
|
return state_events
|