ffmpeg-CVE-2018-6621.patch

From 118e1b0b3370dd1c0da442901b486689efd1654b Mon Sep 17 00:00:00 2001
From: Michael Niedermayer <michael@niedermayer.cc>
Date: Fri, 2 Feb 2018 21:44:57 +0100
Subject: [PATCH] avcodec/utvideodec: Fix bytes left check in decode_frame()

Fixes: out of array read
Fixes: poc-2017.avi

Found-by: GwanYeong Kim <gy741.kim@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavcodec/utvideodec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/utvideodec.c b/libavcodec/utvideodec.c
index 608c8c4..1bcd14e 100644
--- a/libavcodec/utvideodec.c
+++ b/libavcodec/utvideodec.c
@@ -676,7 +676,7 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
             for (j = 0; j < c->slices; j++) {
                 slice_end   = bytestream2_get_le32u(&gb);
                 if (slice_end < 0 || slice_end < slice_start ||
-                    bytestream2_get_bytes_left(&gb) < slice_end) {
+                    bytestream2_get_bytes_left(&gb) < slice_end + 1024LL) {
                     av_log(avctx, AV_LOG_ERROR, "Incorrect slice size\n");
                     return AVERROR_INVALIDDATA;
                 }
-- 
1.9.1