[vlc-commits] demux: mpgv: improve probing

[Francois Cartegnie]

vlc | branch: master | Francois Cartegnie <fcvlcdev at free.fr> | Wed Aug  8 11:35:23 2018 +0200| [244951076e10dca80faeda6aa9fd50a4051888b6] | committer: Francois Cartegnie

demux: mpgv: improve probing

need to reject mpeg4 sequences

> http://git.videolan.org/gitweb.cgi/vlc.git/?a=commit;h=244951076e10dca80faeda6aa9fd50a4051888b6
---

 modules/demux/mpeg/mpgv.c | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/modules/demux/mpeg/mpgv.c b/modules/demux/mpeg/mpgv.c
index 1ab835048d..8e0aea3547 100644
--- a/modules/demux/mpeg/mpgv.c
+++ b/modules/demux/mpeg/mpgv.c
@@ -78,6 +78,26 @@ static void Close( vlc_object_t * p_this )
     free( p_sys );
 }
 
+static int CheckMPEGStartCode( const uint8_t *p_peek )
+{
+    switch( p_peek[3] )
+    {
+        case 0x00:
+            if( (p_peek[5] & 0x38) == 0x00 )
+                return VLC_EGENERIC;
+            break;
+        case 0xB0:
+        case 0xB1:
+        case 0xB6:
+            return VLC_EGENERIC;
+        default:
+            if( p_peek[3] > 0xB9 )
+                return VLC_EGENERIC;
+            break;
+    }
+    return VLC_SUCCESS;
+}
+
 /*****************************************************************************
  * Open: initializes demux structures
  *****************************************************************************/
@@ -91,7 +111,7 @@ static int Open( vlc_object_t * p_this )
 
     es_format_t  fmt;
 
-    if( vlc_stream_Peek( p_demux->s, &p_peek, 4 ) < 4 )
+    if( vlc_stream_Peek( p_demux->s, &p_peek, 8 ) < 8 )
     {
         msg_Dbg( p_demux, "cannot peek" );
         return VLC_EGENERIC;
@@ -107,12 +127,11 @@ static int Open( vlc_object_t * p_this )
         msg_Err( p_demux, "this doesn't look like an MPEG ES stream, continuing" );
     }
 
-    if( p_peek[3] > 0xb9 )
+    if( CheckMPEGStartCode( p_peek ) != VLC_SUCCESS )
     {
         if( !b_forced ) return VLC_EGENERIC;
         msg_Err( p_demux, "this seems to be a system stream (PS plug-in ?), but continuing" );
     }
-
     p_demux->pf_demux  = Demux;
     p_demux->pf_control= Control;
     p_demux->p_sys     = p_sys = malloc( sizeof( demux_sys_t ) );