diff options
| -rw-r--r-- | changelog.d/9814.feature | 1 | ||||
| -rw-r--r-- | synapse/api/auth.py | 1 | ||||
| -rw-r--r-- | synapse/handlers/event_auth.py | 86 | ||||
| -rw-r--r-- | synapse/handlers/federation.py | 44 | ||||
| -rw-r--r-- | synapse/handlers/room_member.py | 62 | ||||
| -rw-r--r-- | synapse/server.py | 5 |
6 files changed, 131 insertions, 68 deletions
diff --git a/changelog.d/9814.feature b/changelog.d/9814.feature new file mode 100644 index 0000000000..9404ad2fc0 --- /dev/null +++ b/changelog.d/9814.feature @@ -0,0 +1 @@ +Update experimental support for [MSC3083](https://github.com/matrix-org/matrix-doc/pull/3083): restricting room access via group membership. diff --git a/synapse/api/auth.py b/synapse/api/auth.py index 872fd100cd..2d845d0d5c 100644 --- a/synapse/api/auth.py +++ b/synapse/api/auth.py @@ -65,6 +65,7 @@ class Auth: """ FIXME: This class contains a mix of functions for authenticating users of our client-server API and authenticating events added to room graphs. + The latter should be moved to synapse.handlers.event_auth.EventAuthHandler. """ def __init__(self, hs): diff --git a/synapse/handlers/event_auth.py b/synapse/handlers/event_auth.py new file mode 100644 index 0000000000..eff639f407 --- /dev/null +++ b/synapse/handlers/event_auth.py @@ -0,0 +1,86 @@ +# Copyright 2021 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. +from typing import TYPE_CHECKING + +from synapse.api.constants import EventTypes, JoinRules +from synapse.api.room_versions import RoomVersion +from synapse.types import StateMap + +if TYPE_CHECKING: + from synapse.server import HomeServer + + +class EventAuthHandler: + """ + This class contains methods for authenticating events added to room graphs. + """ + + def __init__(self, hs: "HomeServer"): + self._store = hs.get_datastore() + + async def can_join_without_invite( + self, state_ids: StateMap[str], room_version: RoomVersion, user_id: str + ) -> bool: + """ + Check whether a user can join a room without an invite. + + When joining a room with restricted joined rules (as defined in MSC3083), + the membership of spaces must be checked during join. + + Args: + state_ids: The state of the room as it currently is. + room_version: The room version of the room being joined. + user_id: The user joining the room. + + Returns: + True if the user can join the room, false otherwise. + """ + # This only applies to room versions which support the new join rule. + if not room_version.msc3083_join_rules: + return True + + # If there's no join rule, then it defaults to invite (so this doesn't apply). + join_rules_event_id = state_ids.get((EventTypes.JoinRules, ""), None) + if not join_rules_event_id: + return True + + # If the join rule is not restricted, this doesn't apply. + join_rules_event = await self._store.get_event(join_rules_event_id) + if join_rules_event.content.get("join_rule") != JoinRules.MSC3083_RESTRICTED: + return True + + # If allowed is of the wrong form, then only allow invited users. + allowed_spaces = join_rules_event.content.get("allow", []) + if not isinstance(allowed_spaces, list): + return False + + # Get the list of joined rooms and see if there's an overlap. + joined_rooms = await self._store.get_rooms_for_user(user_id) + + # Pull out the other room IDs, invalid data gets filtered. + for space in allowed_spaces: + if not isinstance(space, dict): + continue + + space_id = space.get("space") + if not isinstance(space_id, str): + continue + + # The user was joined to one of the spaces specified, they can join + # this room! + if space_id in joined_rooms: + return True + + # The user was not in any of the required spaces. + return False diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py index dbdd7d2db3..9d867aaf4d 100644 --- a/synapse/handlers/federation.py +++ b/synapse/handlers/federation.py @@ -146,6 +146,7 @@ class FederationHandler(BaseHandler): self.is_mine_id = hs.is_mine_id self.spam_checker = hs.get_spam_checker() self.event_creation_handler = hs.get_event_creation_handler() + self._event_auth_handler = hs.get_event_auth_handler() self._message_handler = hs.get_message_handler() self._server_notices_mxid = hs.config.server_notices_mxid self.config = hs.config @@ -1673,8 +1674,40 @@ class FederationHandler(BaseHandler): # would introduce the danger of backwards-compatibility problems. event.internal_metadata.send_on_behalf_of = origin + # Calculate the event context. context = await self.state_handler.compute_event_context(event) - context = await self._auth_and_persist_event(origin, event, context) + + # Get the state before the new event. + prev_state_ids = await context.get_prev_state_ids() + + # Check if the user is already in the room or invited to the room. + user_id = event.state_key + prev_member_event_id = prev_state_ids.get((EventTypes.Member, user_id), None) + newly_joined = True + user_is_invited = False + if prev_member_event_id: + prev_member_event = await self.store.get_event(prev_member_event_id) + newly_joined = prev_member_event.membership != Membership.JOIN + user_is_invited = prev_member_event.membership == Membership.INVITE + + # If the member is not already in the room, and not invited, check if + # they should be allowed access via membership in a space. + if ( + newly_joined + and not user_is_invited + and not await self._event_auth_handler.can_join_without_invite( + prev_state_ids, + event.room_version, + user_id, + ) + ): + raise AuthError( + 403, + "You do not belong to any of the required spaces to join this room.", + ) + + # Persist the event. + await self._auth_and_persist_event(origin, event, context) logger.debug( "on_send_join_request: After _auth_and_persist_event: %s, sigs: %s", @@ -1682,8 +1715,6 @@ class FederationHandler(BaseHandler): event.signatures, ) - prev_state_ids = await context.get_prev_state_ids() - state_ids = list(prev_state_ids.values()) auth_chain = await self.store.get_auth_chain(event.room_id, state_ids) @@ -2006,7 +2037,7 @@ class FederationHandler(BaseHandler): state: Optional[Iterable[EventBase]] = None, auth_events: Optional[MutableStateMap[EventBase]] = None, backfilled: bool = False, - ) -> EventContext: + ) -> None: """ Process an event by performing auth checks and then persisting to the database. @@ -2028,9 +2059,6 @@ class FederationHandler(BaseHandler): event is an outlier), may be the auth events claimed by the remote server. backfilled: True if the event was backfilled. - - Returns: - The event context. """ context = await self._check_event_auth( origin, @@ -2060,8 +2088,6 @@ class FederationHandler(BaseHandler): ) raise - return context - async def _auth_and_persist_events( self, origin: str, diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py index 2bbfac6471..2c5bada1d8 100644 --- a/synapse/handlers/room_member.py +++ b/synapse/handlers/room_member.py @@ -19,7 +19,7 @@ from http import HTTPStatus from typing import TYPE_CHECKING, Iterable, List, Optional, Tuple from synapse import types -from synapse.api.constants import AccountDataTypes, EventTypes, JoinRules, Membership +from synapse.api.constants import AccountDataTypes, EventTypes, Membership from synapse.api.errors import ( AuthError, Codes, @@ -28,7 +28,6 @@ from synapse.api.errors import ( SynapseError, ) from synapse.api.ratelimiting import Ratelimiter -from synapse.api.room_versions import RoomVersion from synapse.events import EventBase from synapse.events.snapshot import EventContext from synapse.types import JsonDict, Requester, RoomAlias, RoomID, StateMap, UserID @@ -64,6 +63,7 @@ class RoomMemberHandler(metaclass=abc.ABCMeta): self.profile_handler = hs.get_profile_handler() self.event_creation_handler = hs.get_event_creation_handler() self.account_data_handler = hs.get_account_data_handler() + self.event_auth_handler = hs.get_event_auth_handler() self.member_linearizer = Linearizer(name="member") @@ -178,62 +178,6 @@ class RoomMemberHandler(metaclass=abc.ABCMeta): await self._invites_per_user_limiter.ratelimit(requester, invitee_user_id) - async def _can_join_without_invite( - self, state_ids: StateMap[str], room_version: RoomVersion, user_id: str - ) -> bool: - """ - Check whether a user can join a room without an invite. - - When joining a room with restricted joined rules (as defined in MSC3083), - the membership of spaces must be checked during join. - - Args: - state_ids: The state of the room as it currently is. - room_version: The room version of the room being joined. - user_id: The user joining the room. - - Returns: - True if the user can join the room, false otherwise. - """ - # This only applies to room versions which support the new join rule. - if not room_version.msc3083_join_rules: - return True - - # If there's no join rule, then it defaults to public (so this doesn't apply). - join_rules_event_id = state_ids.get((EventTypes.JoinRules, ""), None) - if not join_rules_event_id: - return True - - # If the join rule is not restricted, this doesn't apply. - join_rules_event = await self.store.get_event(join_rules_event_id) - if join_rules_event.content.get("join_rule") != JoinRules.MSC3083_RESTRICTED: - return True - - # If allowed is of the wrong form, then only allow invited users. - allowed_spaces = join_rules_event.content.get("allow", []) - if not isinstance(allowed_spaces, list): - return False - - # Get the list of joined rooms and see if there's an overlap. - joined_rooms = await self.store.get_rooms_for_user(user_id) - - # Pull out the other room IDs, invalid data gets filtered. - for space in allowed_spaces: - if not isinstance(space, dict): - continue - - space_id = space.get("space") - if not isinstance(space_id, str): - continue - - # The user was joined to one of the spaces specified, they can join - # this room! - if space_id in joined_rooms: - return True - - # The user was not in any of the required spaces. - return False - async def _local_membership_update( self, requester: Requester, @@ -302,7 +246,7 @@ class RoomMemberHandler(metaclass=abc.ABCMeta): if ( newly_joined and not user_is_invited - and not await self._can_join_without_invite( + and not await self.event_auth_handler.can_join_without_invite( prev_state_ids, event.room_version, user_id ) ): diff --git a/synapse/server.py b/synapse/server.py index 59ae91b503..67598fffe3 100644 --- a/synapse/server.py +++ b/synapse/server.py @@ -77,6 +77,7 @@ from synapse.handlers.devicemessage import DeviceMessageHandler from synapse.handlers.directory import DirectoryHandler from synapse.handlers.e2e_keys import E2eKeysHandler from synapse.handlers.e2e_room_keys import E2eRoomKeysHandler +from synapse.handlers.event_auth import EventAuthHandler from synapse.handlers.events import EventHandler, EventStreamHandler from synapse.handlers.federation import FederationHandler from synapse.handlers.groups_local import GroupsLocalHandler, GroupsLocalWorkerHandler @@ -747,6 +748,10 @@ class HomeServer(metaclass=abc.ABCMeta): return SpaceSummaryHandler(self) @cache_in_self + def get_event_auth_handler(self) -> EventAuthHandler: + return EventAuthHandler(self) + + @cache_in_self def get_external_cache(self) -> ExternalCache: return ExternalCache(self) |