[FFmpeg-devel] [PATCH] avcodec/ffwavesynth: Correct undefined overflow of PINK_UNIT

[James Almer]

On 1/17/2020 8:11 PM, Michael Niedermayer wrote:
> Fixes: signed integer overflow: 9223372036854775775 + 128 cannot be represented in type 'long'
> Fixes: 20054/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_FFWAVESYNTH_fuzzer-5686385113825280
> 
> 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/ffwavesynth.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/libavcodec/ffwavesynth.c b/libavcodec/ffwavesynth.c
> index b9c63abb8d..bb593fbe47 100644
> --- a/libavcodec/ffwavesynth.c
> +++ b/libavcodec/ffwavesynth.c
> @@ -217,7 +217,7 @@ static void wavesynth_seek(struct wavesynth_context *ws, int64_t ts)
>      *last = -1;
>      lcg_seek(&ws->dither_state, (uint32_t)ts - (uint32_t)ws->cur_ts);
>      if (ws->pink_need) {
> -        uint64_t pink_ts_cur  = (ws->cur_ts + PINK_UNIT - 1) & ~(PINK_UNIT - 1);
> +        uint64_t pink_ts_cur  = (ws->cur_ts + (uint64_t)PINK_UNIT - 1) & ~(PINK_UNIT - 1);

Can't you make PINK_UNIT 128UL or 128ULL? Or will that affect other
checks negatively?

>          uint64_t pink_ts_next = ts & ~(PINK_UNIT - 1);
>          int pos = ts & (PINK_UNIT - 1);
>          lcg_seek(&ws->pink_state, (uint32_t)(pink_ts_next - pink_ts_cur) * 2);
>