diff options
Diffstat (limited to 'synapse/events/third_party_rules.py')
| -rw-r--r-- | synapse/events/third_party_rules.py | 245 |
1 files changed, 203 insertions, 42 deletions
diff --git a/synapse/events/third_party_rules.py b/synapse/events/third_party_rules.py index f7944fd834..7a6eb3e516 100644 --- a/synapse/events/third_party_rules.py +++ b/synapse/events/third_party_rules.py @@ -11,16 +11,124 @@ # 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 typing import TYPE_CHECKING, Union - +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 @@ -35,36 +143,65 @@ class ThirdPartyEventRules: self.store = hs.get_datastore() - module = None - config = None - if hs.config.third_party_event_rules: - module, config = hs.config.third_party_event_rules + 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 module is not None: - self.third_party_rules = module( - config=config, - module_api=hs.get_module_api(), + 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 - ) -> Union[bool, dict]: + ) -> 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. - * a dict: replacement event data. + + 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 + The result from the ThirdPartyRules module, as above. """ - if self.third_party_rules is None: - return True + # 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() @@ -77,29 +214,46 @@ class ThirdPartyEventRules: # the hashes and signatures. event.freeze() - return await self.third_party_rules.check_event_allowed(event, state_events) + 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 - ) -> bool: - """Intercept requests to create room to allow, deny or update the - request config. + ) -> 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 - - Returns: - Whether room creation is allowed or denied. """ - - if self.third_party_rules is None: - return True - - return await self.third_party_rules.on_create_room( - requester, config, is_requester_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 @@ -114,15 +268,20 @@ class ThirdPartyEventRules: Returns: True if the 3PID can be invited, False if not. """ - - if self.third_party_rules is None: + # 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) - return await self.third_party_rules.check_threepid_can_be_invited( - medium, address, state_events - ) + 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 @@ -137,18 +296,20 @@ class ThirdPartyEventRules: Returns: True if the room's visibility can be modified, False if not. """ - if self.third_party_rules is None: - return True - - check_func = getattr( - self.third_party_rules, "check_visibility_can_be_modified", None - ) - if not check_func or not callable(check_func): + # 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) - return await check_func(room_id, state_events, new_visibility) + 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. |