[FFmpeg-devel] [PATCH] avcodec/dts2pts_bsf: Avoid poc overflows in cmp_find()

[Andreas Rheinhardt]

Michael Niedermayer:
> Fixes: signed integer overflow: -2147483648 - 5 cannot be represented in type 'int'
> Fixes: 54242/clusterfuzz-testcase-minimized-ffmpeg_BSF_DTS2PTS_fuzzer-472928339243827
> 
> 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/dts2pts_bsf.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/libavcodec/dts2pts_bsf.c b/libavcodec/dts2pts_bsf.c
> index 48612e59db..60bec91f99 100644
> --- a/libavcodec/dts2pts_bsf.c
> +++ b/libavcodec/dts2pts_bsf.c
> @@ -90,9 +90,11 @@ static int cmp_insert(const void *key, const void *node)
>  
>  static int cmp_find(const void *key, const void *node)
>  {
> -    int ret = ((const DTS2PTSFrame *)key)->poc - ((const DTS2PTSNode *) node)->poc;
> +    const DTS2PTSFrame * key1 = key;
> +    const DTS2PTSNode  *node1 = node;
> +    int ret = (key1->poc > node1->poc) - (key1->poc < node1->poc) ;

Don't we have FFDIFFSIGN (or so) for this?

>      if (!ret)
> -        ret = ((const DTS2PTSFrame *)key)->gop - ((const DTS2PTSNode *) node)->gop;
> +        ret = key1->gop - node1->gop;
>      return ret;
>  }
>