[FFmpeg-devel] [PATCH 2/4] avcodec/vorbisdec: amplitude bits can be more than 25 bits
Michael Niedermayer
michael at niedermayer.cc
Mon Jul 8 02:18:03 EEST 2019
Fixes: assertion failure, invalid shift
Fixes: 15583/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VORBIS_fuzzer-5640157484548096
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
libavcodec/vorbisdec.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/libavcodec/vorbisdec.c b/libavcodec/vorbisdec.c
index 00e9cd8a13..7f2d27d1a2 100644
--- a/libavcodec/vorbisdec.c
+++ b/libavcodec/vorbisdec.c
@@ -1097,13 +1097,14 @@ static int vorbis_floor0_decode(vorbis_context *vc,
{
vorbis_floor0 *vf = &vfu->t0;
float *lsp = vf->lsp;
- unsigned amplitude, book_idx;
+ unsigned book_idx;
+ uint64_t amplitude;
unsigned blockflag = vc->modes[vc->mode_number].blockflag;
if (!vf->amplitude_bits)
return 1;
- amplitude = get_bits(&vc->gb, vf->amplitude_bits);
+ amplitude = get_bits64(&vc->gb, vf->amplitude_bits);
if (amplitude > 0) {
float last = 0;
unsigned idx, lsp_len = 0;
@@ -1181,7 +1182,7 @@ static int vorbis_floor0_decode(vorbis_context *vc,
/* calculate linear floor value */
q = exp((((amplitude*vf->amplitude_offset) /
- (((1 << vf->amplitude_bits) - 1) * sqrt(p + q)))
+ (((1ULL << vf->amplitude_bits) - 1) * sqrt(p + q)))
- vf->amplitude_offset) * .11512925f);
/* fill vector */
--
2.22.0
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