diff --git a/changelog.d/9735.feature b/changelog.d/9735.feature
new file mode 100644
index 0000000000..c2c74f13d5
--- /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 31cc20a826..b77187472f 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 1cf12f3255..894ef859f4 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.
|
