diff --git a/synapse/handlers/event_auth.py b/synapse/handlers/event_auth.py
index eff639f407..5b2fe103e7 100644
--- a/synapse/handlers/event_auth.py
+++ b/synapse/handlers/event_auth.py
@@ -11,10 +11,12 @@
# 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 typing import TYPE_CHECKING, Optional
-from synapse.api.constants import EventTypes, JoinRules
+from synapse.api.constants import EventTypes, JoinRules, Membership
+from synapse.api.errors import AuthError
from synapse.api.room_versions import RoomVersion
+from synapse.events import EventBase
from synapse.types import StateMap
if TYPE_CHECKING:
@@ -29,44 +31,58 @@ class EventAuthHandler:
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:
+ async def check_restricted_join_rules(
+ self,
+ state_ids: StateMap[str],
+ room_version: RoomVersion,
+ user_id: str,
+ prev_member_event: Optional[EventBase],
+ ) -> None:
"""
- Check whether a user can join a room without an invite.
+ Check whether a user can join a room without an invite due to restricted join rules.
When joining a room with restricted joined rules (as defined in MSC3083),
- the membership of spaces must be checked during join.
+ the membership of spaces must be checked during a room 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.
+ prev_member_event: The current membership event for this user.
- Returns:
- True if the user can join the room, false otherwise.
+ Raises:
+ AuthError if the user cannot join the room.
"""
+ # If the member is invited or currently joined, then nothing to do.
+ if prev_member_event and (
+ prev_member_event.membership in (Membership.JOIN, Membership.INVITE)
+ ):
+ return
+
# This only applies to room versions which support the new join rule.
if not room_version.msc3083_join_rules:
- return True
+ return
# 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
+ return
# 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
+ return
# 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
+ allowed_spaces = ()
# Get the list of joined rooms and see if there's an overlap.
- joined_rooms = await self._store.get_rooms_for_user(user_id)
+ if allowed_spaces:
+ joined_rooms = await self._store.get_rooms_for_user(user_id)
+ else:
+ joined_rooms = ()
# Pull out the other room IDs, invalid data gets filtered.
for space in allowed_spaces:
@@ -80,7 +96,10 @@ class EventAuthHandler:
# The user was joined to one of the spaces specified, they can join
# this room!
if space_id in joined_rooms:
- return True
+ return
# The user was not in any of the required spaces.
- return False
+ raise AuthError(
+ 403,
+ "You do not belong to any of the required spaces to join this room.",
+ )
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