[FFmpeg-devel] [PATCH 5/5] avcodec/wavpack: Avoid undefined shift in get_tail()

[James Almer]

On 12/18/2022 2:08 PM, Michael Niedermayer wrote:
> Fixes: left shift of 1208485947 by 1 places cannot be represented in type 'int'
> Fixes: 54058/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WAVPACK_fuzzer-5827521084260352
> 
> 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/wavpack.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/libavcodec/wavpack.c b/libavcodec/wavpack.c
> index 3cb4077550..42859ab0a1 100644
> --- a/libavcodec/wavpack.c
> +++ b/libavcodec/wavpack.c
> @@ -129,7 +129,7 @@ static av_always_inline unsigned get_tail(GetBitContext *gb, unsigned k)
>       e   = (1LL << (p + 1)) - k - 1;
>       res = get_bits_long(gb, p);
>       if (res >= e)
> -        res = (res << 1) - e + get_bits1(gb);
> +        res = ((unsigned)res << 1) - e + get_bits1(gb);

Don't we usually do << 1U for this?

>       return res;
>   }
>