diff --git a/src/polkit/polkitsystembusname.c b/src/polkit/polkitsystembusname.c

index 8ed1363..2fbf5f1 100644

--- a/src/polkit/polkitsystembusname.c

+++ b/src/polkit/polkitsystembusname.c

@@ -62,6 +62,10 @@ enum

   PROP_NAME,

 };

+

+guint8 dbus_call_respond_fails;      // has to be global because of callback

+

+

 static void subject_iface_init (PolkitSubjectIface *subject_iface);

 G_DEFINE_TYPE_WITH_CODE (PolkitSystemBusName, polkit_system_bus_name, G_TYPE_OBJECT,

@@ -364,6 +368,7 @@ on_retrieved_unix_uid_pid (GObject              *src,

   if (!v)

     {

       data->caught_error = TRUE;

+      dbus_call_respond_fails += 1;

     }

   else

     {

@@ -405,6 +410,8 @@ polkit_system_bus_name_get_creds_sync (PolkitSystemBusName           *system_bus

   tmp_context = g_main_context_new ();

   g_main_context_push_thread_default (tmp_context);

+  dbus_call_respond_fails = 0;

+

   /* Do two async calls as it's basically as fast as one sync call.

    */

   g_dbus_connection_call (connection,

@@ -432,11 +439,34 @@ polkit_system_bus_name_get_creds_sync (PolkitSystemBusName           *system_bus

 			  on_retrieved_unix_uid_pid,

 			  &data);

-  while (!((data.retrieved_uid && data.retrieved_pid) || data.caught_error))

-    g_main_context_iteration (tmp_context, TRUE);

+  while (TRUE)

+  {

+    /* If one dbus call returns error, we must wait until the other call

+     * calls _call_finish(), otherwise fd leak is possible.

+     * Resolves: GHSL-2021-077

+    */

-  if (data.caught_error)

-    goto out;

+    if ( (dbus_call_respond_fails > 1) )

+    {

+      // we got two faults, we can leave

+      goto out;

+    }

+

+    if ((data.caught_error && (data.retrieved_pid || data.retrieved_uid)))

+    {

+      // we got one fault and the other call finally finished, we can leave

+      goto out;

+    }

+

+    if ( !(data.retrieved_uid && data.retrieved_pid) )

+    {

+      g_main_context_iteration (tmp_context, TRUE);

+    }

+    else

+    {

+      break;

+    }

+  }

   if (out_uid)

     *out_uid = data.uid;