avcodec/vorbisdec: fix FASTDIV usage for vr_type == 2

This reverts a hunk from f1ca40ee00

Fixes: out of array read
Fixes: 16924/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VORBIS_fuzzer-5157893162139648

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 722fd46965)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2019-09-06 12:06:30 +02:00
parent 6c583ec9bd
commit 5b44aec196
1 changed files with 1 additions and 1 deletions

View File

@ -1513,7 +1513,7 @@ static av_always_inline int vorbis_residue_decode_internal(vorbis_context *vc,
}
} else if (vr_type == 2) {
unsigned voffs_div = FASTDIV(voffset << 1, ch <<1);
unsigned voffs_div = ch == 1 ? voffset : FASTDIV(voffset, ch);
unsigned voffs_mod = voffset - voffs_div * ch;
for (k = 0; k < step; ++k) {