[FFmpeg-cvslog] libavformat/mtv: Check for min header size first

[Reynaldo H. Verdejo Pinochet]

ffmpeg | branch: master | Reynaldo H. Verdejo Pinochet <r.verdejo at sisa.samsung.com> | Thu Jan 23 15:43:07 2014 -0300| [30f4c58f6f92765b3d06b0950392e5264630bce0] | committer: Reynaldo H. Verdejo Pinochet

libavformat/mtv: Check for min header size first

Abort immediately if we are not getting enough
data to extract the required fields.

Signed-off-by: Reynaldo H. Verdejo Pinochet <r.verdejo at sisa.samsung.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=30f4c58f6f92765b3d06b0950392e5264630bce0
---

 libavformat/mtv.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/libavformat/mtv.c b/libavformat/mtv.c
index 0517dd2..5e638ca 100644
--- a/libavformat/mtv.c
+++ b/libavformat/mtv.c
@@ -52,12 +52,18 @@ typedef struct MTVDemuxContext {
 
 static int mtv_probe(AVProbeData *p)
 {
+    /* we need at least 57 bytes from the header
+     * to try parsing all required fields
+     */
+    if (p->buf_size < 57)
+        return 0;
+
     /* Magic is 'AMV' */
     if (*p->buf != 'A' || *(p->buf + 1) != 'M' || *(p->buf + 2) != 'V')
         return 0;
 
     /* Check for nonzero in bpp and (width|height) header fields */
-    if(p->buf_size < 57 || !(p->buf[51] && AV_RL16(&p->buf[52]) | AV_RL16(&p->buf[54])))
+    if(!(p->buf[51] && AV_RL16(&p->buf[52]) | AV_RL16(&p->buf[54])))
         return 0;
 
     /* If width or height are 0 then imagesize header field should not */