linux-kernel - Re: [PATCH v3] leds: Introduce userspace leds driver

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Message-ID: <d3f1810c-e97a-4460-1415-f54e8501cf64@lechnology.com>
Date:   Thu, 15 Sep 2016 10:31:50 -0500
From:   David Lechner <david@...hnology.com>
To:     Jacek Anaszewski <j.anaszewski@...sung.com>,
        Pavel Machek <pavel@....cz>
Cc:     Richard Purdie <rpurdie@...ys.net>, linux-kernel@...r.kernel.org,
        linux-leds@...r.kernel.org, Marcel Holtmann <marcel@...tmann.org>
Subject: Re: [PATCH v3] leds: Introduce userspace leds driver

On 09/15/2016 09:54 AM, Jacek Anaszewski wrote:
> Hi Pavel,
>
> On 09/15/2016 03:08 PM, Pavel Machek wrote:
>> Hi!
>>
>>>> +    if (copy_from_user(&udev->user_dev, buffer,
>>>> +               sizeof(struct uleds_user_dev))) {
>>>> +        ret = -EFAULT;
>>>> +        goto out;
>>>> +    }
>>>> +
>>>> +    if (!udev->user_dev.name[0]) {
>>>> +        ret = -EINVAL;
>>>> +        goto out;
>>>> +    }
>>>> +
>>>> +    ret = led_classdev_register(NULL, &udev->led_cdev);
>>>> +    if (ret < 0)
>>>> +        goto out;
>>
>> No sanity checking on the name -> probably a security hole. Do not
>> push this upstream before this is fixed.
>
> Thanks for catching this.
>
> David, please check if the LED name sticks to the LED class
> device naming convention.

I don't think it is a good idea to enforce the LED class naming 
convention. Someone may have a userspace application they want to test 
that has a hard-coded name that does not follow the convention.


>
> And one thing that caught my eye only now - please use
> devm_led_classdev_register().

How do I use devm_* when there is no parent device?


>
> For now I'm dropping the patch.
>