From 0751ccd31505cd2774053553263466c6933b3c42 Mon Sep 17 00:00:00 2001
From: Lars Uebernickel <lars.uebernickel@canonical.com>
Date: Thu, 28 Jan 2016 15:39:18 +0100
Subject: [PATCH] gdbus: fix use-after-free

g_dbus_connection_call_internal() accesses the user data it passes to
g_dbus_connection_send_message_with_reply() after the call. That data
might be freed already in the case that the callback is called
immediately.

Fix this by removing the 'serial' field from the user data altogether
and fetch the serial from the message in the callback.

https://bugzilla.gnome.org/show_bug.cgi?id=748263
---
 gio/gdbusconnection.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/gio/gdbusconnection.c b/gio/gdbusconnection.c
index 4a4f403..8263419 100644
--- a/gio/gdbusconnection.c
+++ b/gio/gdbusconnection.c
@@ -5660,7 +5660,6 @@ typedef struct
 {
   GVariantType *reply_type;
   gchar *method_name; /* for error message */
-  guint32 serial;
 
   GUnixFDList *fd_list;
 } CallState;
@@ -5701,7 +5700,7 @@ g_dbus_connection_call_done (GObject      *source,
                " <<<< ASYNC COMPLETE %s() (serial %d)\n"
                "      ",
                state->method_name,
-               state->serial);
+               g_dbus_message_get_reply_serial (reply));
       if (reply != NULL)
         {
           g_print ("SUCCESS\n");
@@ -5798,11 +5797,10 @@ g_dbus_connection_call_internal (GDBusConnection        *connection,
                                                  message,
                                                  G_DBUS_SEND_MESSAGE_FLAGS_NONE,
                                                  timeout_msec,
-                                                 &state->serial,
+                                                 &serial,
                                                  cancellable,
                                                  g_dbus_connection_call_done,
                                                  task);
-      serial = state->serial;
     }
   else
     {
-- 
2.9.4