Do not propagate profile changes of shadow-banned users into rooms

synapse/handlers/profile.py

@@ -14,6 +14,7 @@
 # limitations under the License.
 
 import logging
+import random
 
 from synapse.api.errors import (
     AuthError,
@@ -213,8 +214,14 @@ async def get_avatar_url(self, target_user):
     async def set_avatar_url(
         self, target_user, requester, new_avatar_url, by_admin=False
     ):
-        """target_user is the user whose avatar_url is to be changed;
-        auth_user is the user attempting to make this change."""
+        """Set a new avatar URL for a user.
+
+        Args:
+            target_user (UserID): the user whose displayname is to be changed.
+            requester (Requester): The user attempting to make this change.
+            new_displayname (str): The displayname to give this user.
+            by_admin (bool): Whether this change was made by an administrator.
+        """
         if not self.hs.is_mine(target_user):
             raise SynapseError(400, "User is not hosted on this homeserver")
 
@@ -278,6 +285,12 @@ async def _update_join_states(self, requester, target_user):
 
         await self.ratelimit(requester)
 
+        # Do not actually update the room state for shadow-banned users.
+        if requester.shadow_banned:
+            # We randomly sleep a bit just to annoy the requester.
+            await self.clock.sleep(random.randint(1, 10))
+            return
+
         room_ids = await self.store.get_rooms_for_user(target_user.to_string())
 
         for room_id in room_ids:

tests/rest/client/test_shadow_banned.py

@@ -16,23 +16,13 @@
 
 import synapse.rest.admin
 from synapse.api.constants import EventTypes
-from synapse.rest.client.v1 import directory, login, room
+from synapse.rest.client.v1 import directory, login, profile, room
 from synapse.rest.client.v2_alpha import room_upgrade_rest_servlet
 
 from tests import unittest
 
 
-# To avoid the tests timing out don't add a delay to "annoy the requester".
-@patch("random.randint", new=lambda a, b: 0)
-class RoomTestCase(unittest.HomeserverTestCase):
-    servlets = [
-        synapse.rest.admin.register_servlets_for_client_rest_resource,
-        directory.register_servlets,
-        login.register_servlets,
-        room.register_servlets,
-        room_upgrade_rest_servlet.register_servlets,
-    ]
-
+class _ShadowBannedBase(unittest.HomeserverTestCase):
     def prepare(self, reactor, clock, homeserver):
         # Create two users, one of which is shadow-banned.
         self.banned_user_id = self.register_user("banned", "test")
@@ -52,6 +42,18 @@ def prepare(self, reactor, clock, homeserver):
         self.other_user_id = self.register_user("otheruser", "pass")
         self.other_access_token = self.login("otheruser", "pass")
 
+
+# To avoid the tests timing out don't add a delay to "annoy the requester".
+@patch("random.randint", new=lambda a, b: 0)
+class RoomTestCase(_ShadowBannedBase):
+    servlets = [
+        synapse.rest.admin.register_servlets_for_client_rest_resource,
+        directory.register_servlets,
+        login.register_servlets,
+        room.register_servlets,
+        room_upgrade_rest_servlet.register_servlets,
+    ]
+
     def test_invite(self):
         """Invites from shadow-banned users don't actually get sent."""
 
@@ -176,3 +178,34 @@ def test_upgrade(self):
         summary = self.get_success(self.store.get_room_summary(new_room_id))
         # The summary should be empty since the room doesn't exist.
         self.assertEqual(summary, {})
+
+
+# To avoid the tests timing out don't add a delay to "annoy the requester".
+@patch("random.randint", new=lambda a, b: 0)
+class ProfileTestCase(_ShadowBannedBase):
+    servlets = [
+        synapse.rest.admin.register_servlets_for_client_rest_resource,
+        login.register_servlets,
+        profile.register_servlets,
+    ]
+
+    def test_displayname(self):
+        """Profile changes should succeed, but don't end up in a room."""
+        # The update should succeed.
+        request, channel = self.make_request(
+            "PUT",
+            "/_matrix/client/r0/profile/%s/displayname" % (self.banned_user_id,),
+            {"displayname": "new display name"},
+            access_token=self.banned_access_token,
+        )
+        self.render(request)
+        self.assertEquals(200, channel.code, channel.result)
+        self.assertEqual(channel.json_body, {})
+
+        # The user's display name should be updated.
+        request, channel = self.make_request(
+            "GET", "/profile/%s/displayname" % (self.banned_user_id,)
+        )
+        self.render(request)
+        self.assertEqual(channel.code, 200, channel.result)
+        self.assertEqual(channel.json_body["displayname"], "new display name")