From b08f7e592f89de8d1a655170387f165ce92c5a69 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sun, 28 May 2017 17:20:42 +0200 Subject: [PATCH] avcodec/ylc: Check count in build_vlc() Fixes: runtime error: signed integer overflow: 211633430 + 2147483647 cannot be represented in type 'int' Fixes: 1874/clusterfuzz-testcase-minimized-5037763613163520 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer (cherry picked from commit 67b30decf7793523f7fdaef6fdf7f1179ef42b18) Signed-off-by: Michael Niedermayer --- libavcodec/ylc.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/libavcodec/ylc.c b/libavcodec/ylc.c index 95a5e05baa..1af880f4d4 100644 --- a/libavcodec/ylc.c +++ b/libavcodec/ylc.c @@ -108,7 +108,7 @@ static int build_vlc(AVCodecContext *avctx, VLC *vlc, const uint32_t *table) int new_node = j; int first_node = cur_node; int second_node = cur_node; - int nd, st; + unsigned nd, st; nodes[cur_node].count = -1; @@ -132,6 +132,10 @@ static int build_vlc(AVCodecContext *avctx, VLC *vlc, const uint32_t *table) st = nodes[first_node].count; nodes[second_node].count = 0; nodes[first_node].count = 0; + if (nd >= UINT32_MAX - st) { + av_log(avctx, AV_LOG_ERROR, "count overflow\n"); + return AVERROR_INVALIDDATA; + } nodes[cur_node].count = nd + st; nodes[cur_node].sym = -1; nodes[cur_node].n0 = cur_node;