[FFmpeg-devel] [PATCH 2/5] avcodec/aaccoder: assert that escape case len is not causing issues

[Lynne]

Apr 28, 2024, 23:31 by michael at niedermayer.cc:

> Inspired by CID1465483 Unintentional integer overflow
>
> Sponsored-by: Sovereign Tech Fund
> Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> ---
>  libavcodec/aaccoder.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/libavcodec/aaccoder.c b/libavcodec/aaccoder.c
> index 4ce54ca8867..6e5817e237b 100644
> --- a/libavcodec/aaccoder.c
> +++ b/libavcodec/aaccoder.c
> @@ -178,6 +178,8 @@ static av_always_inline float quantize_and_encode_band_cost_template(
>  int coef = av_clip_uintp2(quant(fabsf(in[i+j]), Q, ROUNDING), 13);
>  int len = av_log2(coef);
>  
> +                        av_assert2(len >= 4);
> +
>  put_bits(pb, len - 4 + 1, (1 << (len - 4 + 1)) - 2);
>  put_sbits(pb, len, coef);
>  }
>

I'm not sure that's correct to do. Any specific cases where this happens?