[FFmpeg-devel] [PATCH] avfilter/vf_unsharp: Don't dereference NULL

[Paul B Mahol]

LGTM

On 12/1/19, Andreas Rheinhardt <andreas.rheinhardt at gmail.com> wrote:
> The unsharp filter uses an array of arrays of uint32_t, each of which is
> separately allocated. These arrays also need to freed separately; but
> before doing so, one needs to check whether the array of arrays has
> actually been allocated, otherwise one would dereference a NULL pointer.
> This fixes #8408.
>
> Furthermore, the array of arrays needs to be zero-initialized so that
> no uninitialized pointer will be freed in case an allocation of one of
> the individual arrays fails.
>
> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
> ---
>  libavfilter/vf_unsharp.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/libavfilter/vf_unsharp.c b/libavfilter/vf_unsharp.c
> index 95b4968d41..7b430b650d 100644
> --- a/libavfilter/vf_unsharp.c
> +++ b/libavfilter/vf_unsharp.c
> @@ -218,7 +218,7 @@ static int init_filter_param(AVFilterContext *ctx,
> UnsharpFilterParam *fp, const
>             effect, effect_type, fp->msize_x, fp->msize_y, fp->amount /
> 65535.0);
>
>      fp->sr = av_malloc_array((MAX_MATRIX_SIZE - 1) * s->nb_threads,
> sizeof(uint32_t));
> -    fp->sc = av_malloc_array(2 * fp->steps_y * s->nb_threads,
> sizeof(uint32_t **));
> +    fp->sc = av_mallocz_array(2 * fp->steps_y * s->nb_threads,
> sizeof(uint32_t *));
>      if (!fp->sr || !fp->sc)
>          return AVERROR(ENOMEM);
>
> @@ -258,9 +258,11 @@ static void free_filter_param(UnsharpFilterParam *fp,
> int nb_threads)
>  {
>      int z;
>
> -    for (z = 0; z < 2 * fp->steps_y * nb_threads; z++)
> -        av_freep(&fp->sc[z]);
> -    av_freep(&fp->sc);
> +    if (fp->sc) {
> +        for (z = 0; z < 2 * fp->steps_y * nb_threads; z++)
> +            av_freep(&fp->sc[z]);
> +        av_freep(&fp->sc);
> +    }
>      av_freep(&fp->sr);
>  }
>
> --
> 2.20.1
>
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