From 722fd4696583cc984700eaec4745922ae177b2da Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Fri, 6 Sep 2019 12:06:30 +0200 Subject: [PATCH] avcodec/vorbisdec: fix FASTDIV usage for vr_type == 2 This reverts a hunk from f1ca40ee00402102046fc7e59606651930436b0e 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 --- libavcodec/vorbisdec.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libavcodec/vorbisdec.c b/libavcodec/vorbisdec.c index 104dc86a13..be6d1b2d21 100644 --- a/libavcodec/vorbisdec.c +++ b/libavcodec/vorbisdec.c @@ -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) {