From 286930d302fd34cfc2541bfdd760a8bbf9f2d2e5 Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michaelni@gmx.at>
Date: Fri, 25 Jan 2013 00:03:59 +0100
Subject: [PATCH] gifdec: check that w,h is not zero

Fixes out of array access

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
---
 libavcodec/gifdec.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libavcodec/gifdec.c b/libavcodec/gifdec.c
index 2d9f8b4f3d..d52f2d5348 100644
--- a/libavcodec/gifdec.c
+++ b/libavcodec/gifdec.c
@@ -187,6 +187,8 @@ static int gif_read_image(GifState *s)
     if (left + width > s->screen_width ||
         top + height > s->screen_height)
         return AVERROR_INVALIDDATA;
+    if (width <= 0 || height <= 0)
+        return AVERROR_INVALIDDATA;
 
     /* process disposal method */
     if (s->gce_prev_disposal == GCE_DISPOSAL_BACKGROUND) {