[FFmpeg-devel] [PATCH 1/2] avcodec/adpcm_data: extend ff_adpcm_ima_cunning_index_table

[Zane van Iperen]

On Thu, 28 May 2020 14:12:33 +0200
"Michael Niedermayer" <michael at niedermayer.cc> wrote:

> 
> Fixes: overread by 1
> Fixes:
> 21880/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_ADPCM_IMA_CUNNING_fuzzer-5717917221257216.fuzz
> 
> Found-by: continuous fuzzing process
> https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> 
> -const int8_t ff_adpcm_ima_cunning_index_table[8] = {
> -    -1, -1, -1, -1, 1, 2, 3, 4,
> +const int8_t ff_adpcm_ima_cunning_index_table[9] = {
> +    -1, -1, -1, -1, 1, 2, 3, 4, 5
>  };
> 
The index table should only ever be indexed between [0,7], so this
looks like a bug in adpcm_ima_cunning_expand_nibble() instead. 

Where would one go to see the inputs for this? I'd like to investigate
(and test against the original decoder).

Zane