1. ffmpeg
  2. Commit 5b44aec196e6951ecf3dbc0bc0bef91f09e98df8
Browse code

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 <michael@niedermayer.cc>
(cherry picked from commit 722fd4696583cc984700eaec4745922ae177b2da)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

Michael Niedermayer authored on 2019/09/06 19:06:30
Showing 1 changed files
libavcodec/vorbisdec.c
History View file @ 5b44aec
... ... 
@@ -1513,7 +1513,7 @@ static av_always_inline int vorbis_residue_decode_internal(vorbis_context *vc,
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                                 }
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                             } else if (vr_type == 2) {
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-                                unsigned voffs_div = FASTDIV(voffset << 1, ch <<1);
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+                                unsigned voffs_div = ch == 1 ? voffset : FASTDIV(voffset, ch);
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                                 unsigned voffs_mod = voffset - voffs_div * ch;
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                                 for (k = 0; k < step; ++k) {