From f9de136b17bc72ff02f39c6a53756d72bbc4bd15 Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michaelni@gmx.at>
Date: Tue, 24 Jan 2012 18:48:23 +0100
Subject: [PATCH] dv: check stype

Fixes part1 of CVE-2011-3929
Possibly fixes part of CVE-2011-3936

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Reviewed-by: Roman Shaposhnik <roman@shaposhnik.org>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
---
 libavformat/dv.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/libavformat/dv.c b/libavformat/dv.c
index d99dee3782..062c56787f 100644
--- a/libavformat/dv.c
+++ b/libavformat/dv.c
@@ -207,6 +207,12 @@ static int dv_extract_audio_info(DVDemuxContext* c, uint8_t* frame)
     stype = (as_pack[3] & 0x1f);      /* 0 - 2CH, 2 - 4CH, 3 - 8CH */
     quant =  as_pack[4] & 0x07;       /* 0 - 16bit linear, 1 - 12bit nonlinear */
 
+    if (stype > 3) {
+        av_log(c->fctx, AV_LOG_ERROR, "stype %d is invalid\n", stype);
+        c->ach = 0;
+        return 0;
+    }
+
     /* note: ach counts PAIRS of channels (i.e. stereo channels) */
     ach = ((int[4]){  1,  0,  2,  4})[stype];
     if (ach == 1 && quant && freq == 2)