diff --git a/changelog.d/13088.bugfix b/changelog.d/13088.bugfix
new file mode 100644
index 0000000000..7c69801afe
--- /dev/null
+++ b/changelog.d/13088.bugfix
@@ -0,0 +1 @@
+Fix some inconsistencies in the event authentication code.
diff --git a/synapse/event_auth.py b/synapse/event_auth.py
index 440b1ae418..0fc2c4b27e 100644
--- a/synapse/event_auth.py
+++ b/synapse/event_auth.py
@@ -150,7 +150,7 @@ async def check_state_independent_auth_rules(
# 1.5 Otherwise, allow
return
- # Check the auth events.
+ # 2. Reject if event has auth_events that: ...
auth_events = await store.get_events(
event.auth_event_ids(),
redact_behaviour=EventRedactBehaviour.as_is,
@@ -158,6 +158,7 @@ async def check_state_independent_auth_rules(
)
room_id = event.room_id
auth_dict: MutableStateMap[str] = {}
+ expected_auth_types = auth_types_for_event(event.room_version, event)
for auth_event_id in event.auth_event_ids():
auth_event = auth_events.get(auth_event_id)
@@ -179,6 +180,24 @@ async def check_state_independent_auth_rules(
% (event.event_id, room_id, auth_event_id, auth_event.room_id),
)
+ k = (auth_event.type, auth_event.state_key)
+
+ # 2.1 ... have duplicate entries for a given type and state_key pair
+ if k in auth_dict:
+ raise AuthError(
+ 403,
+ f"Event {event.event_id} has duplicate auth_events for {k}: {auth_dict[k]} and {auth_event_id}",
+ )
+
+ # 2.2 ... have entries whose type and state_key don’t match those specified by
+ # the auth events selection algorithm described in the server
+ # specification.
+ if k not in expected_auth_types:
+ raise AuthError(
+ 403,
+ f"Event {event.event_id} has unexpected auth_event for {k}: {auth_event_id}",
+ )
+
# We also need to check that the auth event itself is not rejected.
if auth_event.rejected_reason:
raise AuthError(
@@ -187,7 +206,7 @@ async def check_state_independent_auth_rules(
% (event.event_id, auth_event.event_id),
)
- auth_dict[(auth_event.type, auth_event.state_key)] = auth_event_id
+ auth_dict[k] = auth_event_id
# 3. If event does not have a m.room.create in its auth_events, reject.
creation_event = auth_dict.get((EventTypes.Create, ""), None)
diff --git a/tests/handlers/test_federation.py b/tests/handlers/test_federation.py
index 9afba7b0e8..9b9c11fab7 100644
--- a/tests/handlers/test_federation.py
+++ b/tests/handlers/test_federation.py
@@ -225,9 +225,10 @@ class FederationTestCase(unittest.FederatingHomeserverTestCase):
# we need a user on the remote server to be a member, so that we can send
# extremity-causing events.
+ remote_server_user_id = f"@user:{self.OTHER_SERVER_NAME}"
self.get_success(
event_injection.inject_member_event(
- self.hs, room_id, f"@user:{self.OTHER_SERVER_NAME}", "join"
+ self.hs, room_id, remote_server_user_id, "join"
)
)
@@ -247,6 +248,12 @@ class FederationTestCase(unittest.FederatingHomeserverTestCase):
# create more than is 5 which corresponds to the number of backward
# extremities we slice off in `_maybe_backfill_inner`
federation_event_handler = self.hs.get_federation_event_handler()
+ auth_events = [
+ ev
+ for ev in current_state
+ if (ev.type, ev.state_key)
+ in {("m.room.create", ""), ("m.room.member", remote_server_user_id)}
+ ]
for _ in range(0, 8):
event = make_event_from_dict(
self.add_hashes_and_signatures(
@@ -258,15 +265,14 @@ class FederationTestCase(unittest.FederatingHomeserverTestCase):
"body": "message connected to fake event",
},
"room_id": room_id,
- "sender": f"@user:{self.OTHER_SERVER_NAME}",
+ "sender": remote_server_user_id,
"prev_events": [
ev1.event_id,
# We're creating an backward extremity each time thanks
# to this fake event
generate_fake_event_id(),
],
- # lazy: *everything* is an auth event
- "auth_events": [ev.event_id for ev in current_state],
+ "auth_events": [ev.event_id for ev in auth_events],
"depth": ev1.depth + 1,
},
room_version,
diff --git a/tests/handlers/test_federation_event.py b/tests/handlers/test_federation_event.py
index 1a36c25c41..4b1a8f04db 100644
--- a/tests/handlers/test_federation_event.py
+++ b/tests/handlers/test_federation_event.py
@@ -98,7 +98,6 @@ class FederationEventHandlerTests(unittest.FederatingHomeserverTestCase):
auth_event_ids = [
initial_state_map[("m.room.create", "")],
initial_state_map[("m.room.power_levels", "")],
- initial_state_map[("m.room.join_rules", "")],
member_event.event_id,
]
diff --git a/tests/test_event_auth.py b/tests/test_event_auth.py
index ed7a3cbcee..371cd201af 100644
--- a/tests/test_event_auth.py
+++ b/tests/test_event_auth.py
@@ -150,6 +150,92 @@ class EventAuthTestCase(unittest.TestCase):
event_auth.check_state_independent_auth_rules(event_store, bad_event)
)
+ def test_duplicate_auth_events(self):
+ """Events with duplicate auth_events should be rejected
+
+ https://spec.matrix.org/v1.3/rooms/v9/#authorization-rules
+ 2. Reject if event has auth_events that:
+ 1. have duplicate entries for a given type and state_key pair
+ """
+ creator = "@creator:example.com"
+
+ create_event = _create_event(RoomVersions.V9, creator)
+ join_event1 = _join_event(RoomVersions.V9, creator)
+ pl_event = _power_levels_event(
+ RoomVersions.V9,
+ creator,
+ {"state_default": 30, "users": {"creator": 100}},
+ )
+
+ # create a second join event, so that we can make a duplicate
+ join_event2 = _join_event(RoomVersions.V9, creator)
+
+ event_store = _StubEventSourceStore()
+ event_store.add_events([create_event, join_event1, join_event2, pl_event])
+
+ good_event = _random_state_event(
+ RoomVersions.V9, creator, [create_event, join_event2, pl_event]
+ )
+ bad_event = _random_state_event(
+ RoomVersions.V9, creator, [create_event, join_event1, join_event2, pl_event]
+ )
+ # a variation: two instances of the *same* event
+ bad_event2 = _random_state_event(
+ RoomVersions.V9, creator, [create_event, join_event2, join_event2, pl_event]
+ )
+
+ get_awaitable_result(
+ event_auth.check_state_independent_auth_rules(event_store, good_event)
+ )
+ with self.assertRaises(AuthError):
+ get_awaitable_result(
+ event_auth.check_state_independent_auth_rules(event_store, bad_event)
+ )
+ with self.assertRaises(AuthError):
+ get_awaitable_result(
+ event_auth.check_state_independent_auth_rules(event_store, bad_event2)
+ )
+
+ def test_unexpected_auth_events(self):
+ """Events with excess auth_events should be rejected
+
+ https://spec.matrix.org/v1.3/rooms/v9/#authorization-rules
+ 2. Reject if event has auth_events that:
+ 2. have entries whose type and state_key don’t match those specified by the
+ auth events selection algorithm described in the server specification.
+ """
+ creator = "@creator:example.com"
+
+ create_event = _create_event(RoomVersions.V9, creator)
+ join_event = _join_event(RoomVersions.V9, creator)
+ pl_event = _power_levels_event(
+ RoomVersions.V9,
+ creator,
+ {"state_default": 30, "users": {"creator": 100}},
+ )
+ join_rules_event = _join_rules_event(RoomVersions.V9, creator, "public")
+
+ event_store = _StubEventSourceStore()
+ event_store.add_events([create_event, join_event, pl_event, join_rules_event])
+
+ good_event = _random_state_event(
+ RoomVersions.V9, creator, [create_event, join_event, pl_event]
+ )
+ # join rules should *not* be included in the auth events.
+ bad_event = _random_state_event(
+ RoomVersions.V9,
+ creator,
+ [create_event, join_event, pl_event, join_rules_event],
+ )
+
+ get_awaitable_result(
+ event_auth.check_state_independent_auth_rules(event_store, good_event)
+ )
+ with self.assertRaises(AuthError):
+ get_awaitable_result(
+ event_auth.check_state_independent_auth_rules(event_store, bad_event)
+ )
+
def test_random_users_cannot_send_state_before_first_pl(self):
"""
Check that, before the first PL lands, the creator is the only user
|
