From 452991527a3e76715f0571f81f036ea20de0be36 Mon Sep 17 00:00:00 2001 From: Patrick Cloke Date: Thu, 8 Apr 2021 08:28:32 -0400 Subject: [PATCH] MSC3083: Check for space membership during a local join of restricted rooms. (#9735) When joining a room with join rules set to 'restricted', check if the user is a member of the spaces defined in the 'allow' key of the join rules. This only applies to an experimental room version, as defined in MSC3083. --- changelog.d/9735.feature | 1 + scripts-dev/complement.sh | 2 +- synapse/handlers/room_member.py | 75 ++++++++++++++++++++++++++++++++- 3 files changed, 76 insertions(+), 2 deletions(-) create mode 100644 changelog.d/9735.feature diff --git a/changelog.d/9735.feature b/changelog.d/9735.feature new file mode 100644 index 000000000..c2c74f13d --- /dev/null +++ b/changelog.d/9735.feature @@ -0,0 +1 @@ +Add experimental support for [MSC3083](https://github.com/matrix-org/matrix-doc/pull/3083): restricting room access via group membership. diff --git a/scripts-dev/complement.sh b/scripts-dev/complement.sh index 31cc20a82..b77187472 100755 --- a/scripts-dev/complement.sh +++ b/scripts-dev/complement.sh @@ -46,4 +46,4 @@ if [[ -n "$1" ]]; then fi # Run the tests! -COMPLEMENT_BASE_IMAGE=complement-synapse go test -v -tags synapse_blacklist -count=1 $EXTRA_COMPLEMENT_ARGS ./tests +COMPLEMENT_BASE_IMAGE=complement-synapse go test -v -tags synapse_blacklist,msc3083 -count=1 $EXTRA_COMPLEMENT_ARGS ./tests diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py index 1cf12f325..894ef859f 100644 --- a/synapse/handlers/room_member.py +++ b/synapse/handlers/room_member.py @@ -20,7 +20,7 @@ from http import HTTPStatus from typing import TYPE_CHECKING, Iterable, List, Optional, Tuple from synapse import types -from synapse.api.constants import AccountDataTypes, EventTypes, Membership +from synapse.api.constants import AccountDataTypes, EventTypes, JoinRules, Membership from synapse.api.errors import ( AuthError, Codes, @@ -29,6 +29,7 @@ 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 @@ -178,6 +179,62 @@ 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, @@ -235,9 +292,25 @@ class RoomMemberHandler(metaclass=abc.ABCMeta): if event.membership == Membership.JOIN: 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 is not accepting an invite, + # check if they should be allowed access via membership in a space. + if ( + newly_joined + and not user_is_invited + and not await self._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.", + ) # Only rate-limit if the user actually joined the room, otherwise we'll end # up blocking profile updates.