linux-kernel - Re: [PATCH v2] platform/x86: lenovo-wmi-camera: Use SW_CAMERA_LENS_COVER instead of KEY_CAMERA

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] [day] [month] [year] [list]

Message-ID: <3acc5097-a1bb-4352-acd9-9f31b35dce91@gmx.de>
Date: Sun, 29 Dec 2024 01:48:36 +0100
From: Armin Wolf <W_Armin@....de>
To: Ai Chao <aichao@...inos.cn>, hdegoede@...hat.com,
 ilpo.jarvinen@...ux.intel.com, platform-driver-x86@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] platform/x86: lenovo-wmi-camera: Use
 SW_CAMERA_LENS_COVER instead of KEY_CAMERA_ACESS

Am 27.12.24 um 10:10 schrieb Ai Chao:

> Use SW_CAMERA_LENS_COVER instead of KEY_CAMERA_ACESS_ENABLE and
> KEY_CAMERA_ACESS_DISABLE. When the camera toggle switch was hit,
> the lenovo-wmi-camera driver would report an event code.
>
> Signed-off-by: Ai Chao <aichao@...inos.cn>
> ---
> change for v2
> -Only delays the input-device registration and switches to reporting SW_CAMERA_LENS_COVER.
>
>   drivers/platform/x86/lenovo-wmi-camera.c | 55 ++++++++++++++----------
>   1 file changed, 32 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/platform/x86/lenovo-wmi-camera.c b/drivers/platform/x86/lenovo-wmi-camera.c
> index 0c0bedaf7407..ad296acaf562 100644
> --- a/drivers/platform/x86/lenovo-wmi-camera.c
> +++ b/drivers/platform/x86/lenovo-wmi-camera.c
> @@ -26,10 +26,33 @@ enum {
>   	SW_CAMERA_ON	= 1,
>   };
>
> +static int camera_shutter_input_setup(struct wmi_device *wdev)
> +{
> +	struct lenovo_wmi_priv *priv = dev_get_drvdata(&wdev->dev);
> +	int err;
> +
> +	priv->idev = devm_input_allocate_device(&wdev->dev);
> +	if (!priv->idev)
> +		return -ENOMEM;
> +
> +	priv->idev->name = "Lenovo WMI Camera Button";
> +	priv->idev->phys = "wmi/input0";
> +	priv->idev->id.bustype = BUS_HOST;
> +	priv->idev->dev.parent = &wdev->dev;
> +
> +	__set_bit(EV_SW, priv->idev->evbit);
> +	__set_bit(SW_CAMERA_LENS_COVER, priv->idev->swbit);
> +

Please use input_set_capability() here.

> +	err = input_register_device(priv->idev);
> +	if (err)
> +		return err;

Please set priv->idev back to NULL if input_device_register() fails, or else
lenovo_wmi_notify() will assume that a valid input device was registered when
the next WMI event is received.

Also i suggest that you do not use devm_input_allocate_device() since you need
to be able to free the input device should an error occur during registration.
Better use input_device_allocate() and remove the input device manually inside
lenovo_wmi_remove().

> +
> +	return 0;
> +}
> +
>   static void lenovo_wmi_notify(struct wmi_device *wdev, union acpi_object *obj)
>   {
>   	struct lenovo_wmi_priv *priv = dev_get_drvdata(&wdev->dev);
> -	unsigned int keycode;
>   	u8 camera_mode;
>
>   	if (obj->type != ACPI_TYPE_BUFFER) {
> @@ -53,13 +76,16 @@ static void lenovo_wmi_notify(struct wmi_device *wdev, union acpi_object *obj)
>   		return;
>   	}
>
> +	if (!priv->idev)
> +		if (camera_shutter_input_setup(wdev))
> +			return;

Please move this piece of code below "mutex_lock(&priv->notify_lock)" to make
sure that only a single thread tries to register a input device at the same time.

> +
>   	mutex_lock(&priv->notify_lock);
>
> -	keycode = camera_mode == SW_CAMERA_ON ?
> -		   KEY_CAMERA_ACCESS_ENABLE : KEY_CAMERA_ACCESS_DISABLE;
> -	input_report_key(priv->idev, keycode, 1);
> -	input_sync(priv->idev);
> -	input_report_key(priv->idev, keycode, 0);
> +	if (camera_mode == SW_CAMERA_ON)
> +		input_report_switch(priv->idev, SW_CAMERA_LENS_COVER, 1);
> +	else if (camera_mode == SW_CAMERA_OFF)
> +		input_report_switch(priv->idev, SW_CAMERA_LENS_COVER, 0);

The second if statement is necessary, we already validated camera_mode before.

Thanks,
Armin Wolf

>   	input_sync(priv->idev);
>
>   	mutex_unlock(&priv->notify_lock);
> @@ -68,29 +94,12 @@ static void lenovo_wmi_notify(struct wmi_device *wdev, union acpi_object *obj)
>   static int lenovo_wmi_probe(struct wmi_device *wdev, const void *context)
>   {
>   	struct lenovo_wmi_priv *priv;
> -	int ret;
>
>   	priv = devm_kzalloc(&wdev->dev, sizeof(*priv), GFP_KERNEL);
>   	if (!priv)
>   		return -ENOMEM;
>
>   	dev_set_drvdata(&wdev->dev, priv);
> -
> -	priv->idev = devm_input_allocate_device(&wdev->dev);
> -	if (!priv->idev)
> -		return -ENOMEM;
> -
> -	priv->idev->name = "Lenovo WMI Camera Button";
> -	priv->idev->phys = "wmi/input0";
> -	priv->idev->id.bustype = BUS_HOST;
> -	priv->idev->dev.parent = &wdev->dev;
> -	input_set_capability(priv->idev, EV_KEY, KEY_CAMERA_ACCESS_ENABLE);
> -	input_set_capability(priv->idev, EV_KEY, KEY_CAMERA_ACCESS_DISABLE);
> -
> -	ret = input_register_device(priv->idev);
> -	if (ret)
> -		return ret;
> -
>   	mutex_init(&priv->notify_lock);
>
>   	return 0;