linux-kernel - Re: [PATCH 1/1] media: v4l: Don't turn on privacy LED if streamon fails

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <50457efb-f145-4eac-a625-28e3bfc8a7af@redhat.com>
Date: Wed, 10 Apr 2024 12:12:33 +0200
From: Hans de Goede <hdegoede@...hat.com>
To: Sakari Ailus <sakari.ailus@...ux.intel.com>, linux-media@...r.kernel.org
Cc: tomi.valkeinen@...asonboard.com,
 Mauro Carvalho Chehab <mchehab@...nel.org>, Hans Verkuil
 <hverkuil@...all.nl>, Laurent Pinchart <laurent.pinchart@...asonboard.com>,
 Umang Jain <umang.jain@...asonboard.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] media: v4l: Don't turn on privacy LED if streamon
 fails

Hi Sakari,

Thank you for fixing this.

On 4/10/24 12:03 PM, Sakari Ailus wrote:
> Turn on the privacy LED only if streamon succeeds. This can be done after
> enabling streaming on the sensor.
> 
> Fixes: b6e10ff6c23d ("media: v4l2-core: Make the v4l2-core code enable/disable the privacy LED if present")
> Signed-off-by: Sakari Ailus <sakari.ailus@...ux.intel.com>
> ---
>  drivers/media/v4l2-core/v4l2-subdev.c | 19 ++++++++++---------
>  1 file changed, 10 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
> index 4c6198c48dd6..acb7c3003ab6 100644
> --- a/drivers/media/v4l2-core/v4l2-subdev.c
> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
> @@ -412,15 +412,6 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
>  	if (WARN_ON(!!sd->enabled_streams == !!enable))
>  		return 0;
>  
> -#if IS_REACHABLE(CONFIG_LEDS_CLASS)
> -	if (!IS_ERR_OR_NULL(sd->privacy_led)) {
> -		if (enable)
> -			led_set_brightness(sd->privacy_led,
> -					   sd->privacy_led->max_brightness);
> -		else
> -			led_set_brightness(sd->privacy_led, 0);
> -	}
> -#endif
>  	ret = sd->ops->video->s_stream(sd, enable);
>  
>  	if (!enable && ret < 0) {
> @@ -431,6 +422,16 @@ static int call_s_stream(struct v4l2_subdev *sd, int enable)
>  	if (!ret)
>  		sd->enabled_streams = enable ? BIT(0) : 0;
>  
> +#if IS_REACHABLE(CONFIG_LEDS_CLASS)
> +	if (!IS_ERR_OR_NULL(sd->privacy_led) && !(enable && ret < 0)) {

There already is a:

	if (!enable && ret < 0)
		ret = 0;

block above to ignore stream-off errors, so you can just test for:

	if (!ret && !IS_ERR_OR_NULL(sd->privacy_led)) {
		...
	}

And then you can move the whole block to inside the existing:

	if (!ret)
		sd->enabled_streams = enable ? BIT(0) : 0;

block, so you get something like this:

	if (!ret) {
		sd->enabled_streams = enable ? BIT(0) : 0;
#if IS_REACHABLE(CONFIG_LEDS_CLASS)
		if (!IS_ERR_OR_NULL(sd->privacy_led)) {
			if (enable)
				led_set_brightness(sd->privacy_led,
						   sd->privacy_led->max_brightness);
			else
				led_set_brightness(sd->privacy_led, 0);
		}
#endif
	}

Which then cleans up nicely by Tomi's patch
introducing the privacy LED helper functions,
to something like this:

	if (!ret {
		if (enable) {
			sd->enabled_streams = BIT(0);
			v4l2_subdev_enable_privacy_led(sd);
		} else {
			sd->enabled_streams = 0;
			v4l2_subdev_disable_privacy_led(sd);
		}
	}

Regards,

Hans