avcodec/ituh263dec: Make the condition for the studio slice start code match between ff_h263_resync() and ff_mpeg4_decode_studio_slice_header()

If they mismatch an infinite loop can occur
Fixes: Timeout (infinite loop)
Fixes: 17043/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MPEG4_fuzzer-5695051748868096

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2019-09-14 18:31:40 +02:00
parent fbb314b6f2
commit 8335ba8ae9
1 changed files with 1 additions and 1 deletions

View File

@ -222,7 +222,7 @@ int ff_h263_resync(MpegEncContext *s){
get_bits(&s->gb, 8);
}
if (show_bits_long(&s->gb, 32) == SLICE_START_CODE)
if (get_bits_left(&s->gb) >= 32 && show_bits_long(&s->gb, 32) == SLICE_START_CODE)
return get_bits_count(&s->gb);
else
return -1;