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From: Rui Miguel Silva <rmfrfs@gmail.com>
To: Mikhail Lobanov <m.lobanov@rosalinux.ru>
Cc: Mikhail Lobanov <m.lobanov@rosalinux.ru>, Greg Kroah-Hartman
 <gregkh@linuxfoundation.org>, greybus-dev@lists.linaro.org,
 linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] greybus: Fix deref of NULL in
 __gb_lights_flash_brightness_set
In-Reply-To: <20240301190425.120605-1-m.lobanov@rosalinux.ru>
References: <20240301190425.120605-1-m.lobanov@rosalinux.ru>
Date: Wed, 06 Mar 2024 09:21:39 +0000
Message-ID: <m38r2v67h8.fsf@gmail.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain

Hi Mikhail,
Mikhail Lobanov <m.lobanov@rosalinux.ru> writes:

> Dereference of null pointer in the __gb_lights_flash_brightness_set function.
> Assigning the channel the result of executing the get_channel_from_mode function
> without checking for NULL may result in an error.
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Fixes: 2870b52bae4c ("greybus: lights: add lights implementation")
> Signed-off-by: Mikhail Lobanov <m.lobanov@rosalinux.ru>

Are you sending a new version with the changes suggested in this thread?
or do you want me to prepare something with your reported-by tag?

Cheers,
    Rui

> ---
>  drivers/staging/greybus/light.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/staging/greybus/light.c b/drivers/staging/greybus/light.c
> index 87d36948c610..929514350947 100644
> --- a/drivers/staging/greybus/light.c
> +++ b/drivers/staging/greybus/light.c
> @@ -148,10 +148,15 @@ static int __gb_lights_flash_brightness_set(struct gb_channel *channel)
>  						GB_CHANNEL_MODE_TORCH);
>  
>  	/* For not flash we need to convert brightness to intensity */
> -	intensity = channel->intensity_uA.min +
> +
> +	if (channel) {
> +		intensity = channel->intensity_uA.min +
>  			(channel->intensity_uA.step * channel->led->brightness);
>  
> -	return __gb_lights_flash_intensity_set(channel, intensity);
> +		return __gb_lights_flash_intensity_set(channel, intensity);
> +	}
> +
> +	return 0;
>  }
>  #else
>  static struct gb_channel *get_channel_from_cdev(struct led_classdev *cdev)
> -- 
> 2.43.0