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Message-ID: <Y8W7FaNouVxmeWox@valkosipuli.retiisi.eu>
Date: Mon, 16 Jan 2023 23:01:09 +0200
From: Sakari Ailus <sakari.ailus@....fi>
To: Aleksandr Burakov <a.burakov@...alinux.ru>
Cc: Mauro Carvalho Chehab <mchehab@...nel.org>,
linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
lvc-project@...uxtesting.org
Subject: Re: [PATCH] media: v4l2-flash: fix NULL dereference in
v4l2_flash_s_ctrl()
Hi Alexandr,
On Wed, Dec 07, 2022 at 05:18:07PM +0300, Aleksandr Burakov wrote:
> The NULL check added for fled_cdev before dereference.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Signed-off-by: Aleksandr Burakov <a.burakov@...alinux.ru>
> Fixes: 42bd6f59ae90 ("media: Add registration helpers for V4L2 flash sub-devices")
> ---
> drivers/media/v4l2-core/v4l2-flash-led-class.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/media/v4l2-core/v4l2-flash-led-class.c b/drivers/media/v4l2-core/v4l2-flash-led-class.c
> index 355595a0fefa..36cc46e80eea 100644
> --- a/drivers/media/v4l2-core/v4l2-flash-led-class.c
> +++ b/drivers/media/v4l2-core/v4l2-flash-led-class.c
> @@ -291,12 +291,16 @@ static int v4l2_flash_s_ctrl(struct v4l2_ctrl *c)
> * No conversion is needed as LED Flash class also uses
> * microseconds for flash timeout units.
> */
> + if (!fled_cdev)
> + return -EINVAL;
> return led_set_flash_timeout(fled_cdev, c->val);
> case V4L2_CID_FLASH_INTENSITY:
> /*
> * No conversion is needed as LED Flash class also uses
> * microamperes for flash intensity units.
> */
> + if (!fled_cdev)
> + return -EINVAL;
> return led_set_flash_brightness(fled_cdev, c->val);
> }
>
fled_cdev won't be NULL above, this is checked elsewhere in the V4L2 flash
LED class code. I guess the question then is whether doing such a check is
meaningful. It would require a bug elsewhere in the code to happen.
--
Kind regards,
Sakari Ailus
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