avformat/mpegts: Shuffle avio_seek

This avoids accessing an old, no longer valid buffer.
Fixes: out of array access
Fixes: crash_audio-2020

Found-by: le wu <shoulewoba@gmail.com>
Reviewed-by: Marton Balint <cus@passwd.hu>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit cd74af1416)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2020-05-07 12:38:26 +02:00
parent 36786f54e7
commit b0b8ce0002
1 changed files with 4 additions and 3 deletions

View File

@ -2765,15 +2765,16 @@ static int mpegts_resync(AVFormatContext *s, int seekback, const uint8_t *curren
AVIOContext *pb = s->pb;
int c, i;
uint64_t pos = avio_tell(pb);
avio_seek(pb, -FFMIN(seekback, pos), SEEK_CUR);
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, SEEK_CUR);
avio_seek(pb, 12 - back, SEEK_CUR);
return 0;
}
avio_seek(pb, -back, SEEK_CUR);
for (i = 0; i < ts->resync_size; i++) {
c = avio_r8(pb);
if (avio_feof(pb))