diff --git a/synapse/rest/admin/__init__.py b/synapse/rest/admin/__init__.py
index 6f7dc06503..f04740cd38 100644
--- a/synapse/rest/admin/__init__.py
+++ b/synapse/rest/admin/__init__.py
@@ -51,6 +51,7 @@ from synapse.rest.admin.users import (
PushersRestServlet,
ResetPasswordRestServlet,
SearchUsersRestServlet,
+ ShadowBanRestServlet,
UserAdminServlet,
UserMediaRestServlet,
UserMembershipRestServlet,
@@ -230,6 +231,7 @@ def register_servlets(hs, http_server):
EventReportsRestServlet(hs).register(http_server)
PushersRestServlet(hs).register(http_server)
MakeRoomAdminRestServlet(hs).register(http_server)
+ ShadowBanRestServlet(hs).register(http_server)
def register_servlets_for_client_rest_resource(hs, http_server):
diff --git a/synapse/rest/admin/users.py b/synapse/rest/admin/users.py
index 86198bab30..68c3c64a0d 100644
--- a/synapse/rest/admin/users.py
+++ b/synapse/rest/admin/users.py
@@ -890,3 +890,39 @@ class UserTokenRestServlet(RestServlet):
)
return 200, {"access_token": token}
+
+
+class ShadowBanRestServlet(RestServlet):
+ """An admin API for shadow-banning a user.
+
+ A shadow-banned users receives successful responses to their client-server
+ API requests, but the events are not propagated into rooms.
+
+ Shadow-banning a user should be used as a tool of last resort and may lead
+ to confusing or broken behaviour for the client.
+
+ Example:
+
+ POST /_synapse/admin/v1/users/@test:example.com/shadow_ban
+ {}
+
+ 200 OK
+ {}
+ """
+
+ PATTERNS = admin_patterns("/users/(?P<user_id>[^/]*)/shadow_ban")
+
+ def __init__(self, hs: "HomeServer"):
+ self.hs = hs
+ self.store = hs.get_datastore()
+ self.auth = hs.get_auth()
+
+ async def on_POST(self, request, user_id):
+ await assert_requester_is_admin(self.auth, request)
+
+ if not self.hs.is_mine_id(user_id):
+ raise SynapseError(400, "Only local users can be shadow-banned")
+
+ await self.store.set_shadow_banned(UserID.from_string(user_id), True)
+
+ return 200, {}
diff --git a/synapse/storage/databases/main/registration.py b/synapse/storage/databases/main/registration.py
index 585b4049d6..0618b4387a 100644
--- a/synapse/storage/databases/main/registration.py
+++ b/synapse/storage/databases/main/registration.py
@@ -360,6 +360,35 @@ class RegistrationWorkerStore(CacheInvalidationWorkerStore):
await self.db_pool.runInteraction("set_server_admin", set_server_admin_txn)
+ async def set_shadow_banned(self, user: UserID, shadow_banned: bool) -> None:
+ """Sets whether a user shadow-banned.
+
+ Args:
+ user: user ID of the user to test
+ shadow_banned: true iff the user is to be shadow-banned, false otherwise.
+ """
+
+ def set_shadow_banned_txn(txn):
+ self.db_pool.simple_update_one_txn(
+ txn,
+ table="users",
+ keyvalues={"name": user.to_string()},
+ updatevalues={"shadow_banned": shadow_banned},
+ )
+ # In order for this to apply immediately, clear the cache for this user.
+ tokens = self.db_pool.simple_select_onecol_txn(
+ txn,
+ table="access_tokens",
+ keyvalues={"user_id": user.to_string()},
+ retcol="token",
+ )
+ for token in tokens:
+ self._invalidate_cache_and_stream(
+ txn, self.get_user_by_access_token, (token,)
+ )
+
+ await self.db_pool.runInteraction("set_shadow_banned", set_shadow_banned_txn)
+
def _query_for_auth(self, txn, token: str) -> Optional[TokenLookupResult]:
sql = """
SELECT users.name as user_id,
|