Re: [PATCH 1/1] media: v4l: subdev: Make link validation safer

[Hans de Goede <hdegoede@redhat.com>]

Hi Sakari, 

On 3/9/23 13:27, Sakari Ailus wrote:
> Link validation currently accesses invalid pointers if the link passed to it
> is not between two sub-devices. This is of course a driver bug.
> 
> Ignore the error but print a debug message, as this is how it used to work
> previously.
> 
> Fixes: a6b995ed03ff ("media: subdev: use streams in v4l2_subdev_link_validate()")
> Reported-by: Hans de Goede <hdegoede@redhat.com>
> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
> Reported-and-tested-by: Hans de Goede <hdegoede@redhat.com>

FWIW you have my Reported-by in there twice now ...

Regards,

Hans




> ---
>  drivers/media/v4l2-core/v4l2-subdev.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> index 1bebcda2bd20c..dd911180ec899 100644
> --- a/drivers/media/v4l2-core/v4l2-subdev.c
> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> @@ -1209,6 +1209,17 @@ int v4l2_subdev_link_validate(struct media_link *link)
>  	struct v4l2_subdev_state *source_state, *sink_state;
>  	int ret;
>  
> +	if (!is_media_entity_v4l2_subdev(link->sink->entity)) {
> +		pr_warn_once("entity \"%s\" not a V4L2 sub-device, driver bug!\n",
> +			     link->sink->entity->name);
> +		return 0;
> +	}
> +	if (!is_media_entity_v4l2_subdev(link->source->entity)) {
> +		pr_warn_once("entity \"%s\" not a V4L2 sub-device, driver bug!\n",
> +			     link->source->entity->name);
> +		return 0;
> +	}
> +
>  	sink_sd = media_entity_to_v4l2_subdev(link->sink->entity);
>  	source_sd = media_entity_to_v4l2_subdev(link->source->entity);
>