From 0897402ac8a2045691395380a9fd2ea88c0d3798 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Fri, 30 Oct 2020 21:50:32 +0100 Subject: [PATCH] avformat/mpc8: correct integer overflow in mpc8_parse_seektable() Fixes: signed integer overflow: -4683718486770919638 * 2 cannot be represented in type 'long' Fixes: 26704/clusterfuzz-testcase-minimized-ffmpeg_dem_MPC8_fuzzer-6327056939614208 Fixes: 27550/clusterfuzz-testcase-minimized-ffmpeg_dem_MPC8_fuzzer-6259212652642304 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavformat/mpc8.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libavformat/mpc8.c b/libavformat/mpc8.c index 2b5eefe8c3..a7ad908ca4 100644 --- a/libavformat/mpc8.c +++ b/libavformat/mpc8.c @@ -182,7 +182,7 @@ static void mpc8_parse_seektable(AVFormatContext *s, int64_t off) t += get_bits(&gb, 12); if(t & 1) t = -(t & ~1); - pos = (t >> 1) + ppos[0]*2 - ppos[1]; + pos = (t >> 1) + (uint64_t)ppos[0]*2 - ppos[1]; av_add_index_entry(s->streams[0], pos, (int64_t)i << seekd, 0, 0, AVINDEX_KEYFRAME); ppos[1] = ppos[0]; ppos[0] = pos;