[grilo-plugins] upnp: Prevent crash with some UPnP servers

[Juan A. Suarez Romero <jasuarez src gnome org>]

commit 61fce31b9dc9fc6b246f0cb533f62877ad509ed8
Author: Bastien Nocera <hadess hadess net>
Date:   Thu Feb 20 12:42:02 2014 +0100

    upnp: Prevent crash with some UPnP servers
    
    The "Skifta" iOS UPnP server seems to pass us " " as a list
    of changed items. We need to protect better against bad input and
    avoid accessing data beyond the array.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=724793

 src/upnp/grl-upnp.c |   23 ++++++++++++++++-------
 1 files changed, 16 insertions(+), 7 deletions(-)
---
diff --git a/src/upnp/grl-upnp.c b/src/upnp/grl-upnp.c
index abe7567..a60631a 100644
--- a/src/upnp/grl-upnp.c
+++ b/src/upnp/grl-upnp.c
@@ -320,16 +320,25 @@ container_changed_cb (GUPnPServiceProxy *proxy,
   tokens = g_strsplit (g_value_get_string (value), ",", -1);
   changed_medias = g_ptr_array_sized_new (g_strv_length (tokens) / 2);
   while (tokens[i]) {
-    container = grl_media_box_new ();
-    grl_media_set_id (container, tokens[i]);
-    g_ptr_array_add (changed_medias, container);
+    gchar *token;
+
+    token = g_strstrip (tokens[i]);
+    if (token && *token != '\0') {
+      container = grl_media_box_new ();
+      grl_media_set_id (container, tokens[i]);
+      g_ptr_array_add (changed_medias, container);
+    }
     i += 2;
+    if (i > g_strv_length (tokens))
+      break;
   }
 
-  grl_source_notify_change_list (source,
-                                 changed_medias,
-                                 GRL_CONTENT_CHANGED,
-                                 FALSE);
+  if (changed_medias->len > 0) {
+    grl_source_notify_change_list (source,
+                                   changed_medias,
+                                   GRL_CONTENT_CHANGED,
+                                   FALSE);
+  }
   g_strfreev (tokens);
 }