From b5f4836f8cb374f1a5ae45db48b61a1dfba0daad Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michaelni@gmx.at>
Date: Mon, 12 Nov 2012 01:22:31 +0100
Subject: [PATCH] vc1: check image height, fix division by 0

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
---
 libavcodec/vc1dec.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/libavcodec/vc1dec.c b/libavcodec/vc1dec.c
index 1e78f385f8..7c07138007 100644
--- a/libavcodec/vc1dec.c
+++ b/libavcodec/vc1dec.c
@@ -5521,6 +5521,11 @@ static int vc1_decode_frame(AVCodecContext *avctx, void *data,
         goto err;
     }
 
+    if ((s->mb_height >> v->field_mode) == 0) {
+        av_log(v->s.avctx, AV_LOG_ERROR, "image too short\n");
+        goto err;
+    }
+
     // process pulldown flags
     s->current_picture_ptr->f.repeat_pict = 0;
     // Pulldown flags are only valid when 'broadcast' has been set.