Treat "\u0000" as "\u0020" for the purposes of message search (message indexing)

changelog.d/10820.misc

@@ -0,0 +1 @@
+Made a change so that posting an event with "\u0000" no longer causes an internal server error.

synapse/storage/databases/main/search.py

@@ -15,7 +15,7 @@
 import logging
 import re
 from collections import namedtuple
-from typing import Collection, List, Optional, Set
+from typing import Collection, Iterable, List, Optional, Set
 
 from synapse.api.errors import SynapseError
 from synapse.events import EventBase
@@ -33,7 +33,7 @@
 
 
 class SearchWorkerStore(SQLBaseStore):
-    def store_search_entries_txn(self, txn, entries):
+    def store_search_entries_txn(self, txn, entries: Iterable[SearchEntry]):
         """Add entries to the search table
 
         Args:
@@ -55,7 +55,7 @@ def store_search_entries_txn(self, txn, entries):
                     entry.event_id,
                     entry.room_id,
                     entry.key,
-                    entry.value,
+                    entry.value.replace("\u0000", "\u0020"),
                     entry.stream_ordering,
                     entry.origin_server_ts,
                 )

tests/test_null_byte_insertion.py

@@ -0,0 +1,43 @@
+# Copyright 2021 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# 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.
+
+
+import synapse.rest.admin
+from synapse.rest.client import account, login, register, room
+
+from tests.unittest import HomeserverTestCase
+
+
+class NullByteInsertionTest(HomeserverTestCase):
+    servlets = [
+        synapse.rest.admin.register_servlets_for_client_rest_resource,
+        login.register_servlets,
+        account.register_servlets,
+        register.register_servlets,
+        room.register_servlets,
+    ]
+
+    def setUp(self):
+        super().setUp()
+
+    # Note that this test must be run with postgres or else is meaningless,
+    # as sqlite will accept insertion of null code points
+    def test_null_byte(self):
+        self.register_user("alice", "password")
+        access_token = self.login("alice", "password")
+        room_id = self.helper.create_room_as("alice", True, "1", access_token)
+        body = '{"body":"\u0000", "msgtype":"m.text"}'
+
+        resp = self.helper.send(room_id, body, "1", access_token)
+        self.assertTrue("event_id" in resp)