Add a shadow-banned flag to users

changelog.d/8092.feature

@@ -0,0 +1 @@
+Add support for shadow-banning users (ignoring any message send requests).

synapse/api/auth.py

@@ -213,6 +213,7 @@ async def get_user_by_req(
             user = user_info["user"]
             token_id = user_info["token_id"]
             is_guest = user_info["is_guest"]
+            shadow_banned = user_info["shadow_banned"]
 
             # Deny the request if the user account has expired.
             if self._account_validity.enabled and not allow_expired:
@@ -252,7 +253,12 @@ async def get_user_by_req(
                 opentracing.set_tag("device_id", device_id)
 
             return synapse.types.create_requester(
-                user, token_id, is_guest, device_id, app_service=app_service
+                user,
+                token_id,
+                is_guest,
+                shadow_banned,
+                device_id,
+                app_service=app_service,
             )
         except KeyError:
             raise MissingClientTokenError()
@@ -297,6 +303,7 @@ async def get_user_by_access_token(
             dict that includes:
                `user` (UserID)
                `is_guest` (bool)
+               `shadow_banned` (bool)
                `token_id` (int|None): access token id. May be None if guest
                `device_id` (str|None): device corresponding to access token
         Raises:
@@ -356,6 +363,7 @@ async def get_user_by_access_token(
                 ret = {
                     "user": user,
                     "is_guest": True,
+                    "shadow_banned": False,
                     "token_id": None,
                     # all guests get the same device id
                     "device_id": GUEST_DEVICE_ID,
@@ -365,6 +373,7 @@ async def get_user_by_access_token(
                 ret = {
                     "user": user,
                     "is_guest": False,
+                    "shadow_banned": False,
                     "token_id": None,
                     "device_id": None,
                 }
@@ -488,6 +497,7 @@ async def _look_up_user_by_access_token(self, token):
             "user": UserID.from_string(ret.get("name")),
             "token_id": ret.get("token_id", None),
             "is_guest": False,
+            "shadow_banned": ret.get("shadow_banned"),
             "device_id": ret.get("device_id"),
             "valid_until_ms": ret.get("valid_until_ms"),
         }

synapse/handlers/register.py

@@ -142,6 +142,7 @@ async def register_user(
         address=None,
         bind_emails=[],
         by_admin=False,
+        shadow_banned=False,
     ):
         """Registers a new client on the server.
 
@@ -159,6 +160,7 @@ async def register_user(
             bind_emails (List[str]): list of emails to bind to this account.
             by_admin (bool): True if this registration is being made via the
               admin api, otherwise False.
+            shadow_banned (bool): Shadow-ban the created user.
         Returns:
             str: user_id
         Raises:
@@ -194,6 +196,7 @@ async def register_user(
                 admin=admin,
                 user_type=user_type,
                 address=address,
+                shadow_banned=shadow_banned,
             )
 
             if self.hs.config.user_directory_search_all_users:
@@ -224,6 +227,7 @@ async def register_user(
                         make_guest=make_guest,
                         create_profile_with_displayname=default_display_name,
                         address=address,
+                        shadow_banned=shadow_banned,
                     )
 
                     # Successfully registered
@@ -529,6 +533,7 @@ def register_with_store(
         admin=False,
         user_type=None,
         address=None,
+        shadow_banned=False,
     ):
         """Register user in the datastore.
 
@@ -546,6 +551,7 @@ def register_with_store(
             user_type (str|None): type of user. One of the values from
                 api.constants.UserTypes, or None for a normal user.
             address (str|None): the IP address used to perform the registration.
+            shadow_banned (bool): Whether to shadow-ban the user
 
         Returns:
             Awaitable
@@ -561,6 +567,7 @@ def register_with_store(
                 admin=admin,
                 user_type=user_type,
                 address=address,
+                shadow_banned=shadow_banned,
             )
         else:
             return self.store.register_user(
@@ -572,6 +579,7 @@ def register_with_store(
                 create_profile_with_displayname=create_profile_with_displayname,
                 admin=admin,
                 user_type=user_type,
+                shadow_banned=shadow_banned,
             )
 
     async def register_device(

synapse/replication/http/register.py

@@ -44,6 +44,7 @@ async def _serialize_payload(
         admin,
         user_type,
         address,
+        shadow_banned,
     ):
         """
         Args:
@@ -60,6 +61,7 @@ async def _serialize_payload(
             user_type (str|None): type of user. One of the values from
                 api.constants.UserTypes, or None for a normal user.
             address (str|None): the IP address used to perform the regitration.
+            shadow_banned (bool): Whether to shadow-ban the user
         """
         return {
             "password_hash": password_hash,
@@ -70,6 +72,7 @@ async def _serialize_payload(
             "admin": admin,
             "user_type": user_type,
             "address": address,
+            "shadow_banned": shadow_banned,
         }
 
     async def _handle_request(self, request, user_id):
@@ -87,6 +90,7 @@ async def _handle_request(self, request, user_id):
             admin=content["admin"],
             user_type=content["user_type"],
             address=content["address"],
+            shadow_banned=content["shadow_banned"],
         )
 
         return 200, {}

synapse/storage/databases/main/registration.py

@@ -304,7 +304,7 @@ def set_server_admin_txn(txn):
 
     def _query_for_auth(self, txn, token):
         sql = (
-            "SELECT users.name, users.is_guest, access_tokens.id as token_id,"
+            "SELECT users.name, users.is_guest, users.shadow_banned, access_tokens.id as token_id,"
             " access_tokens.device_id, access_tokens.valid_until_ms"
             " FROM users"
             " INNER JOIN access_tokens on users.name = access_tokens.user_id"
@@ -952,6 +952,7 @@ def register_user(
         create_profile_with_displayname=None,
         admin=False,
         user_type=None,
+        shadow_banned=False,
     ):
         """Attempts to register an account.
 
@@ -968,6 +969,8 @@ def register_user(
             admin (boolean): is an admin user?
             user_type (str|None): type of user. One of the values from
                 api.constants.UserTypes, or None for a normal user.
+            shadow_banned (bool): Whether the user is shadow-banned,
+                i.e. they may be told their requests succeeded but we ignore them.
 
         Raises:
             StoreError if the user_id could not be registered.
@@ -986,6 +989,7 @@ def register_user(
             create_profile_with_displayname,
             admin,
             user_type,
+            shadow_banned,
         )
 
     def _register_user(
@@ -999,6 +1003,7 @@ def _register_user(
         create_profile_with_displayname,
         admin,
         user_type,
+        shadow_banned,
     ):
         user_id_obj = UserID.from_string(user_id)
 
@@ -1028,6 +1033,7 @@ def _register_user(
                         "appservice_id": appservice_id,
                         "admin": 1 if admin else 0,
                         "user_type": user_type,
+                        "shadow_banned": shadow_banned,
                     },
                 )
             else:
@@ -1042,6 +1048,7 @@ def _register_user(
                         "appservice_id": appservice_id,
                         "admin": 1 if admin else 0,
                         "user_type": user_type,
+                        "shadow_banned": shadow_banned,
                     },
                 )
 

synapse/storage/databases/main/schema/delta/58/09shadow_ban.sql

@@ -0,0 +1,18 @@
+/* Copyright 2020 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.
+ */
+
+-- A shadow-banned user may be told that their requests succeeded when they were
+-- actually ignored.
+ALTER TABLE users ADD COLUMN shadow_banned BOOLEAN;

synapse/types.py

@@ -51,7 +51,15 @@ class Collection(Iterable[T_co], Container[T_co], Sized):  # type: ignore
 
 class Requester(
     namedtuple(
-        "Requester", ["user", "access_token_id", "is_guest", "device_id", "app_service"]
+        "Requester",
+        [
+            "user",
+            "access_token_id",
+            "is_guest",
+            "shadow_banned",
+            "device_id",
+            "app_service",
+        ],
     )
 ):
     """
@@ -62,6 +70,7 @@ class Requester(
         access_token_id (int|None):  *ID* of the access token used for this
             request, or None if it came via the appservice API or similar
         is_guest (bool):  True if the user making this request is a guest user
+        shadow_banned (bool):  True if the user making this request has been shadow-banned.
         device_id (str|None):  device_id which was set at authentication time
         app_service (ApplicationService|None):  the AS requesting on behalf of the user
     """
@@ -77,6 +86,7 @@ def serialize(self):
             "user_id": self.user.to_string(),
             "access_token_id": self.access_token_id,
             "is_guest": self.is_guest,
+            "shadow_banned": self.shadow_banned,
             "device_id": self.device_id,
             "app_server_id": self.app_service.id if self.app_service else None,
         }
@@ -101,13 +111,19 @@ def deserialize(store, input):
             user=UserID.from_string(input["user_id"]),
             access_token_id=input["access_token_id"],
             is_guest=input["is_guest"],
+            shadow_banned=input["shadow_banned"],
             device_id=input["device_id"],
             app_service=appservice,
         )
 
 
 def create_requester(
-    user_id, access_token_id=None, is_guest=False, device_id=None, app_service=None
+    user_id,
+    access_token_id=None,
+    is_guest=False,
+    shadow_banned=False,
+    device_id=None,
+    app_service=None,
 ):
     """
     Create a new ``Requester`` object
@@ -117,6 +133,7 @@ def create_requester(
         access_token_id (int|None):  *ID* of the access token used for this
             request, or None if it came via the appservice API or similar
         is_guest (bool):  True if the user making this request is a guest user
+        shadow_banned (bool):  True if the user making this request is shadow-banned.
         device_id (str|None):  device_id which was set at authentication time
         app_service (ApplicationService|None):  the AS requesting on behalf of the user
 
@@ -125,7 +142,9 @@ def create_requester(
     """
     if not isinstance(user_id, UserID):
         user_id = UserID.from_string(user_id)
-    return Requester(user_id, access_token_id, is_guest, device_id, app_service)
+    return Requester(
+        user_id, access_token_id, is_guest, shadow_banned, device_id, app_service
+    )
 
 
 def get_domain_from_id(string):

tests/storage/test_cleanup_extrems.py

@@ -38,7 +38,7 @@ def prepare(self, reactor, clock, homeserver):
 
         # Create a test user and room
         self.user = UserID("alice", "test")
-        self.requester = Requester(self.user, None, False, None, None)
+        self.requester = Requester(self.user, None, False, False, None, None)
         info, _ = self.get_success(self.room_creator.create_room(self.requester, {}))
         self.room_id = info["room_id"]
 
@@ -260,7 +260,7 @@ def prepare(self, reactor, clock, homeserver):
         # Create a test user and room
         self.user = UserID.from_string(self.register_user("user1", "password"))
         self.token1 = self.login("user1", "password")
-        self.requester = Requester(self.user, None, False, None, None)
+        self.requester = Requester(self.user, None, False, False, None, None)
         info, _ = self.get_success(self.room_creator.create_room(self.requester, {}))
         self.room_id = info["room_id"]
         self.event_creator = homeserver.get_event_creation_handler()

tests/storage/test_event_metrics.py

@@ -27,7 +27,7 @@ def test_exposed_to_prometheus(self):
         room_creator = self.hs.get_room_creation_handler()
 
         user = UserID("alice", "test")
-        requester = Requester(user, None, False, None, None)
+        requester = Requester(user, None, False, False, None, None)
 
         # Real events, forward extremities
         events = [(3, 2), (6, 2), (4, 6)]

tests/storage/test_roommember.py

@@ -187,7 +187,7 @@ def test_can_rerun_update(self):
 
         # Now let's create a room, which will insert a membership
         user = UserID("alice", "test")
-        requester = Requester(user, None, False, None, None)
+        requester = Requester(user, None, False, False, None, None)
         self.get_success(self.room_creator.create_room(requester, {}))
 
         # Register the background update to run again.

tests/test_federation.py

@@ -42,7 +42,7 @@ def setUp(self):
         )
 
         user_id = UserID("us", "test")
-        our_user = Requester(user_id, None, False, None, None)
+        our_user = Requester(user_id, None, False, False, None, None)
         room_creator = self.homeserver.get_room_creation_handler()
         room_deferred = ensureDeferred(
             room_creator.create_room(

tests/unittest.py

@@ -250,7 +250,11 @@ async def get_user_by_access_token(token=None, allow_guest=False):
 
                 async def get_user_by_req(request, allow_guest=False, rights="access"):
                     return create_requester(
-                        UserID.from_string(self.helper.auth_user_id), 1, False, None
+                        UserID.from_string(self.helper.auth_user_id),
+                        1,
+                        False,
+                        False,
+                        None,
                     )
 
                 self.hs.get_auth().get_user_by_req = get_user_by_req
@@ -540,7 +544,7 @@ def create_and_send_event(
         """
         event_creator = self.hs.get_event_creation_handler()
         secrets = self.hs.get_secrets()
-        requester = Requester(user, None, False, None, None)
+        requester = Requester(user, None, False, False, None, None)
 
         event, context = self.get_success(
             event_creator.create_event(