[FFmpeg-devel] [PATCH 19/19] avfilter/af_headphone: Fix segfault upon allocation failure

[Paul B Mahol]

On 8/25/20, Andreas Rheinhardt <andreas.rheinhardt at gmail.com> wrote:
> The headphone filter uses a variable number of inpads and allocates them
> in its init function; if all goes well, the number of inpads coincides
> with a number stored in the filter's private context. Yet if allocating a
> subsequent inpad fails, the uninit function nevertheless uses the number
> stored in the private context to determine the number of inpads to free
> and not the AVFilterContext's nb_inputs. This will lead to an access
> beyond the end of the allocated AVFilterContext.input_pads array and
> an invalid free.
>
> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
> ---
> This is not the only thing wrong in this filter. Will send a separate
> patchset for it.
>
>  libavfilter/af_headphone.c | 7 ++-----
>  1 file changed, 2 insertions(+), 5 deletions(-)
>

LGTM

> diff --git a/libavfilter/af_headphone.c b/libavfilter/af_headphone.c
> index 552ad84837..751f4ab53d 100644
> --- a/libavfilter/af_headphone.c
> +++ b/libavfilter/af_headphone.c
> @@ -812,7 +812,6 @@ static int config_output(AVFilterLink *outlink)
>  static av_cold void uninit(AVFilterContext *ctx)
>  {
>      HeadphoneContext *s = ctx->priv;
> -    int i;
>
>      av_fft_end(s->ifft[0]);
>      av_fft_end(s->ifft[1]);
> @@ -834,11 +833,9 @@ static av_cold void uninit(AVFilterContext *ctx)
>      av_freep(&s->data_hrtf[1]);
>      av_freep(&s->fdsp);
>
> -    for (i = 0; i < s->nb_inputs; i++) {
> -        if (ctx->input_pads && i)
> -            av_freep(&ctx->input_pads[i].name);
> -    }
>      av_freep(&s->in);
> +    for (unsigned i = 1; i < ctx->nb_inputs; i++)
> +        av_freep(&ctx->input_pads[i].name);
>  }
>
>  #define OFFSET(x) offsetof(HeadphoneContext, x)
> --
> 2.20.1
>
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".