[vlc-commits] libvlc: fix race on input_item_t.p_stats

[Rémi Denis-Courmont]

vlc/vlc-3.0 | branch: master | Rémi Denis-Courmont <remi at remlab.net> | Mon Dec 11 21:09:25 2017 +0200| [5e5379efc90044c3199b668482f95a91975dd201] | committer: Rémi Denis-Courmont

libvlc: fix race on input_item_t.p_stats

p_stats is written with the input item lock (by the input thread).
Thus the input item lock is necessary to read and dereference p_stats.

(cherry picked from commit 1fffacd6ea5df99f8d22111b13dfcfd3bcd49bca)

> http://git.videolan.org/gitweb.cgi/vlc/vlc-3.0.git/?a=commit;h=5e5379efc90044c3199b668482f95a91975dd201
---

 lib/media.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/lib/media.c b/lib/media.c
index af246c6c7e..54875d6a0e 100644
--- a/lib/media.c
+++ b/lib/media.c
@@ -698,10 +698,20 @@ libvlc_media_subitems( libvlc_media_t * p_md )
 int libvlc_media_get_stats( libvlc_media_t *p_md,
                             libvlc_media_stats_t *p_stats )
 {
+    input_item_t *item = p_md->p_input_item;
+
     if( !p_md->p_input_item )
         return false;
 
+    vlc_mutex_lock( &item->lock );
+
     input_stats_t *p_itm_stats = p_md->p_input_item->p_stats;
+    if( p_itm_stats == NULL )
+    {
+        vlc_mutex_unlock( &item->lock );
+        return false;
+    }
+
     vlc_mutex_lock( &p_itm_stats->lock );
     p_stats->i_read_bytes = p_itm_stats->i_read_bytes;
     p_stats->f_input_bitrate = p_itm_stats->f_input_bitrate;
@@ -724,6 +734,7 @@ int libvlc_media_get_stats( libvlc_media_t *p_md,
     p_stats->i_sent_bytes = p_itm_stats->i_sent_bytes;
     p_stats->f_send_bitrate = p_itm_stats->f_send_bitrate;
     vlc_mutex_unlock( &p_itm_stats->lock );
+    vlc_mutex_unlock( &item->lock );
     return true;
 }