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| author | Michael Niedermayer <michael@niedermayer.cc> | 2017-05-13 19:28:01 +0200 |
|---|---|---|
| committer | Michael Niedermayer <michael@niedermayer.cc> | 2017-05-13 20:36:33 +0200 |
| commit | 9351a156de724edb69ba6e1f05884fe806a13a21 (patch) | |
| tree | a35b183a331085ed67f733383f63a579426b7235 /libavcodec/ac3dec.c | |
| parent | a3508cc3fe643a8adad6a82a60bece3ea3c5dc63 (diff) | |
| download | ffmpeg-9351a156de724edb69ba6e1f05884fe806a13a21.tar.gz | |
avcodec/ac3dec: Keep track of band structure
It is needed in some corner cases that seem not to be forbidden
Fixes: out of array index
Fixes: 1538/clusterfuzz-testcase-minimized-4696904925446144
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
Diffstat (limited to 'libavcodec/ac3dec.c')
| -rw-r--r-- | libavcodec/ac3dec.c | 27 |
1 files changed, 15 insertions, 12 deletions
diff --git a/libavcodec/ac3dec.c b/libavcodec/ac3dec.c index 7e2cbce90b..ffea9d335c 100644 --- a/libavcodec/ac3dec.c +++ b/libavcodec/ac3dec.c @@ -761,30 +761,31 @@ static void ac3_upmix_delay(AC3DecodeContext *s) * @param[in] default_band_struct default band structure table * @param[out] num_bands number of bands (optionally NULL) * @param[out] band_sizes array containing the number of bins in each band (optionally NULL) + * @param[in,out] band_struct current band structure */ static void decode_band_structure(GetBitContext *gbc, int blk, int eac3, int ecpl, int start_subband, int end_subband, const uint8_t *default_band_struct, - int *num_bands, uint8_t *band_sizes) + int *num_bands, uint8_t *band_sizes, + uint8_t *band_struct, int band_struct_size) { int subbnd, bnd, n_subbands, n_bands=0; uint8_t bnd_sz[22]; - uint8_t coded_band_struct[22]; - const uint8_t *band_struct; n_subbands = end_subband - start_subband; + if (!blk) + memcpy(band_struct, default_band_struct, band_struct_size); + + av_assert0(band_struct_size >= start_subband + n_subbands); + + band_struct += start_subband + 1; + /* decode band structure from bitstream or use default */ if (!eac3 || get_bits1(gbc)) { for (subbnd = 0; subbnd < n_subbands - 1; subbnd++) { - coded_band_struct[subbnd] = get_bits1(gbc); + band_struct[subbnd] = get_bits1(gbc); } - band_struct = coded_band_struct; - } else if (!blk) { - band_struct = &default_band_struct[start_subband+1]; - } else { - /* no change in band structure */ - return; } /* calculate number of bands and band sizes based on band structure. @@ -863,7 +864,8 @@ static inline int spx_strategy(AC3DecodeContext *s, int blk) start_subband, end_subband, ff_eac3_default_spx_band_struct, &s->num_spx_bands, - s->spx_band_sizes); + s->spx_band_sizes, + s->spx_band_struct, sizeof(s->spx_band_struct)); return 0; } @@ -1000,7 +1002,8 @@ static inline int coupling_strategy(AC3DecodeContext *s, int blk, decode_band_structure(bc, blk, s->eac3, 0, cpl_start_subband, cpl_end_subband, ff_eac3_default_cpl_band_struct, - &s->num_cpl_bands, s->cpl_band_sizes); + &s->num_cpl_bands, s->cpl_band_sizes, + s->cpl_band_struct, sizeof(s->cpl_band_struct)); } else { /* coupling not in use */ for (ch = 1; ch <= fbw_channels; ch++) { |