From 33f10546ec012ad4e1054b57317885cded7e953e Mon Sep 17 00:00:00 2001 From: Anton Khirnov Date: Sun, 14 Aug 2016 10:18:39 +0200 Subject: [PATCH] vc1: check that slices have a positive height Fixes possible invalid reads. CC: libav-stable@libav.org Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind --- libavcodec/vc1dec.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/libavcodec/vc1dec.c b/libavcodec/vc1dec.c index 3d042d0b0d..b26fbf2eff 100644 --- a/libavcodec/vc1dec.c +++ b/libavcodec/vc1dec.c @@ -881,6 +881,12 @@ static int vc1_decode_frame(AVCodecContext *avctx, void *data, s->end_mb_y = (i == n_slices ) ? mb_height : FFMIN(mb_height, slices[i].mby_start % mb_height); else s->end_mb_y = (i <= n_slices1 + 1) ? mb_height : FFMIN(mb_height, slices[i].mby_start % mb_height); + + if (s->end_mb_y <= s->start_mb_y) { + av_log(v->s.avctx, AV_LOG_ERROR, "Invalid slice size\n"); + goto err; + } + ff_vc1_decode_blocks(v); if (i != n_slices) s->gb = slices[i].gb;