From 21c9d92646f375f0c3ff9b2bc7b2f5f07a150e74 Mon Sep 17 00:00:00 2001
From: Laurent Aimar <fenrir@videolan.org>
Date: Sat, 24 Sep 2011 23:16:17 +0200
Subject: [PATCH] Fix potential overread in vmd audio decoder.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit 00cbe9e4053fd562b6f21e76aca6636ff926b637)
---
 libavcodec/vmdav.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/libavcodec/vmdav.c b/libavcodec/vmdav.c
index b9acfe921c..ebc8c7eb1d 100644
--- a/libavcodec/vmdav.c
+++ b/libavcodec/vmdav.c
@@ -523,7 +523,10 @@ static int vmdaudio_decode_frame(AVCodecContext *avctx,
 
     silent_chunks = 0;
     if (block_type == BLOCK_TYPE_INITIAL) {
-        uint32_t flags = AV_RB32(buf);
+        uint32_t flags;
+        if (buf_size < 4)
+            return -1;
+        flags = AV_RB32(buf);
         silent_chunks  = av_popcount(flags);
         buf      += 4;
         buf_size -= 4;