From 20d6a6fa5aceb2895743d780be7a13eea52d343b Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michael@niedermayer.cc>
Date: Wed, 15 Nov 2017 21:17:16 +0100
Subject: [PATCH] avcodec/snowdec: Check for remaining bitstream in
 decode_blocks()

Fixes: Timeout
Fixes: 3142/clusterfuzz-testcase-5007853163118592

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 4527ec2216109867498edc3ac8a17fd879b5d017)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavcodec/snowdec.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libavcodec/snowdec.c b/libavcodec/snowdec.c
index f95f538f6c..4506c9b815 100644
--- a/libavcodec/snowdec.c
+++ b/libavcodec/snowdec.c
@@ -434,6 +434,8 @@ static int decode_blocks(SnowContext *s){
 
     for(y=0; y<h; y++){
         for(x=0; x<w; x++){
+            if (s->c.bytestream >= s->c.bytestream_end)
+                return AVERROR_INVALIDDATA;
             if ((res = decode_q_branch(s, 0, x, y)) < 0)
                 return res;
         }