[glib/portal] Avoid a use-after-free

[Matthias Clasen <matthiasc src gnome org>]

commit 01404fbe83b0e3555e7eb76b02d6ecf672e142b4
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Jul 6 19:10:33 2016 -0400

    Avoid a use-after-free
    
    Instead of pulling parent_window out of a copy of the environment
    and having it go bad when we free the copy, move the definition
    of GAppLaunchContextPrivate up and use the envp member without
    copying in.
    
    Pointed out by Cosimo Cecchi.

 gio/gappinfo.c |   17 ++++++-----------
 1 files changed, 6 insertions(+), 11 deletions(-)
---
diff --git a/gio/gappinfo.c b/gio/gappinfo.c
index ad3b999..f19e401 100644
--- a/gio/gappinfo.c
+++ b/gio/gappinfo.c
@@ -90,6 +90,10 @@
  * different ideas of what a given URI means.
  */
 
+struct _GAppLaunchContextPrivate {
+  char **envp;
+};
+
 typedef GAppInfoIface GAppInfoInterface;
 G_DEFINE_INTERFACE (GAppInfo, g_app_info, G_TYPE_OBJECT)
 
@@ -683,13 +687,8 @@ launch_default_with_portal (const char         *uri,
   if (session_bus == NULL)
     return FALSE;
 
-  if (context)
-    {
-      char **env;
-      env = g_app_launch_context_get_environment (context);
-      parent_window = g_environ_getenv (env, "PARENT_WINDOW_ID");
-      g_strfreev (env);
-    }
+  if (context && context->priv->envp)
+    parent_window = g_environ_getenv (context->priv->envp, "PARENT_WINDOW_ID");
 
   g_variant_builder_init (&opt_builder, G_VARIANT_TYPE_VARDICT);
 
@@ -841,10 +840,6 @@ enum {
   LAST_SIGNAL
 };
 
-struct _GAppLaunchContextPrivate {
-  char **envp;
-};
-
 static guint signals[LAST_SIGNAL] = { 0 };
 
 G_DEFINE_TYPE_WITH_PRIVATE (GAppLaunchContext, g_app_launch_context, G_TYPE_OBJECT)