Re: [PATCH] audio: fix wavcapture segfault

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 5/21/20 7:29 PM, Bruce Rogers wrote:
> Commit 571a8c522e caused the HMP wavcapture command to segfault when
> processing audio data in audio_pcm_sw_write(), where a NULL
> sw->hw->pcm_ops is dereferenced. This fix checks that the pointer is
> valid before dereferincing it. A similar fix is also made in the
> parallel function audio_pcm_sw_read().
> 
> Fixes: 571a8c522e (audio: split ctl_* functions into enable_* and
> volume_*)
> Signed-off-by: Bruce Rogers <brogers@suse.com>
> ---
>   audio/audio.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/audio/audio.c b/audio/audio.c
> index 7a9e680355..08a067722b 100644
> --- a/audio/audio.c
> +++ b/audio/audio.c
> @@ -649,7 +649,7 @@ static size_t audio_pcm_sw_read(SWVoiceIn *sw, void *buf, size_t size)
>           total += isamp;
>       }
>   
> -    if (!hw->pcm_ops->volume_in) {
> +    if (hw->pcm_ops && !hw->pcm_ops->volume_in) {
>           mixeng_volume (sw->buf, ret, &sw->vol);
>       }
>   
> @@ -736,7 +736,7 @@ static size_t audio_pcm_sw_write(SWVoiceOut *sw, void *buf, size_t size)
>       if (swlim) {
>           sw->conv (sw->buf, buf, swlim);
>   
> -        if (!sw->hw->pcm_ops->volume_out) {
> +        if (sw->hw->pcm_ops && !sw->hw->pcm_ops->volume_out) {
>               mixeng_volume (sw->buf, swlim, &sw->vol);
>           }
>       }
> 

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>