Change display names/avatar URLs to None if they contain null bytes before storing in DB (#11230)

* change display names/avatar URLS to None if they contain null bytes

* add changelog

* add POC test, requested changes

* add a saner test and remove old one

* update test to verify that display name has been changed to None

* make test less fragile
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Shay 2021-11-12 10:38:24 -08:00 committed by GitHub
parent 9b90b9454b
commit 0bcae8ad56
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3 changed files with 56 additions and 4 deletions

2
changelog.d/11230.bugfix Normal file
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@ -0,0 +1,2 @@
Fix a long-standing bug wherein display names or avatar URLs containing null bytes cause an internal server error
when stored in the DB.

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@ -1641,8 +1641,8 @@ class PersistEventsStore:
def _store_room_members_txn(self, txn, events, backfilled): def _store_room_members_txn(self, txn, events, backfilled):
"""Store a room member in the database.""" """Store a room member in the database."""
def str_or_none(val: Any) -> Optional[str]: def non_null_str_or_none(val: Any) -> Optional[str]:
return val if isinstance(val, str) else None return val if isinstance(val, str) and "\u0000" not in val else None
self.db_pool.simple_insert_many_txn( self.db_pool.simple_insert_many_txn(
txn, txn,
@ -1654,8 +1654,10 @@ class PersistEventsStore:
"sender": event.user_id, "sender": event.user_id,
"room_id": event.room_id, "room_id": event.room_id,
"membership": event.membership, "membership": event.membership,
"display_name": str_or_none(event.content.get("displayname")), "display_name": non_null_str_or_none(
"avatar_url": str_or_none(event.content.get("avatar_url")), event.content.get("displayname")
),
"avatar_url": non_null_str_or_none(event.content.get("avatar_url")),
} }
for event in events for event in events
], ],

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@ -161,6 +161,54 @@ class RoomMemberStoreTestCase(unittest.HomeserverTestCase):
) )
self.assertEqual(users.keys(), {self.u_alice, self.u_bob}) self.assertEqual(users.keys(), {self.u_alice, self.u_bob})
def test__null_byte_in_display_name_properly_handled(self):
room = self.helper.create_room_as(self.u_alice, tok=self.t_alice)
res = self.get_success(
self.store.db_pool.simple_select_list(
"room_memberships",
{"user_id": "@alice:test"},
["display_name", "event_id"],
)
)
# Check that we only got one result back
self.assertEqual(len(res), 1)
# Check that alice's display name is "alice"
self.assertEqual(res[0]["display_name"], "alice")
# Grab the event_id to use later
event_id = res[0]["event_id"]
# Create a profile with the offending null byte in the display name
new_profile = {"displayname": "ali\u0000ce"}
# Ensure that the change goes smoothly and does not fail due to the null byte
self.helper.change_membership(
room,
self.u_alice,
self.u_alice,
"join",
extra_data=new_profile,
tok=self.t_alice,
)
res2 = self.get_success(
self.store.db_pool.simple_select_list(
"room_memberships",
{"user_id": "@alice:test"},
["display_name", "event_id"],
)
)
# Check that we only have two results
self.assertEqual(len(res2), 2)
# Filter out the previous event using the event_id we grabbed above
row = [row for row in res2 if row["event_id"] != event_id]
# Check that alice's display name is now None
self.assertEqual(row[0]["display_name"], None)
class CurrentStateMembershipUpdateTestCase(unittest.HomeserverTestCase): class CurrentStateMembershipUpdateTestCase(unittest.HomeserverTestCase):
def prepare(self, reactor, clock, homeserver): def prepare(self, reactor, clock, homeserver):