From 83b2e4c8f15a00f037040131e26e20de83f0d842 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Thu, 16 Sep 2021 23:12:42 +0200 Subject: [PATCH] avformat/mpegts: use actually read packet size in mpegts_resync special case Fixes: infinite loop Fixes: 37986/clusterfuzz-testcase-minimized-ffmpeg_dem_MPEGTSRAW_fuzzer-5292311517462528 - Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Reviewed-by: Marton Balint Signed-off-by: Michael Niedermayer --- libavformat/mpegts.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/libavformat/mpegts.c b/libavformat/mpegts.c index da8eee2414..9b2930e4d1 100644 --- a/libavformat/mpegts.c +++ b/libavformat/mpegts.c @@ -2875,8 +2875,8 @@ static int mpegts_resync(AVFormatContext *s, int seekback, const uint8_t *curren int64_t back = FFMIN(seekback, pos); //Special case for files like 01c56b0dc1.ts - if (current_packet[0] == 0x80 && current_packet[12] == 0x47) { - avio_seek(pb, 12 - back, SEEK_CUR); + if (current_packet[0] == 0x80 && current_packet[12] == 0x47 && pos >= TS_PACKET_SIZE) { + avio_seek(pb, 12 - TS_PACKET_SIZE, SEEK_CUR); return 0; }