[FFmpeg-devel] [PATCH 1/6] avcodec/alac: Check for bps of 0

[James Almer]

On 8/25/2019 3:41 PM, Michael Niedermayer wrote:
> Fixes: shift exponent 32 is too large for 32-bit type 'unsigned int'
> Fixes: 15764/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_ALAC_fuzzer-5102101203517440
> 
> 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/alac.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/libavcodec/alac.c b/libavcodec/alac.c
> index 6086e2caa8..782d461b22 100644
> --- a/libavcodec/alac.c
> +++ b/libavcodec/alac.c
> @@ -250,10 +250,12 @@ static int decode_element(AVCodecContext *avctx, AVFrame *frame, int ch_index,
>  
>      alac->extra_bits = get_bits(&alac->gb, 2) << 3;
>      bps = alac->sample_size - alac->extra_bits + channels - 1;
> -    if (bps > 32U) {
> +    if (bps > 32) {
>          avpriv_report_missing_feature(avctx, "bps %d", bps);
>          return AVERROR_PATCHWELCOME;
>      }
> +    if (bps < 1)
> +        return AVERROR_INVALIDDATA;
>  
>      /* whether the frame is compressed */
>      is_compressed = !get_bits1(&alac->gb);

LGTM.