Re: [PATCH v3] leds: Introduce userspace leds driver

[David Lechner]

On 09/16/2016 12:51 AM, Pavel Machek wrote:
> On Thu 2016-09-15 10:31:50, David Lechner wrote:
> > 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.
>
> Umm.
>
> Noone has applications with hardcoded names that are not possible
> today, right?
>
> And better not encourage crazy names.
>
> Best regards,
> 									Pavel

Here is the actual `ls /sys/class/leds` from my Raspberry Pi:

led0                      pistorms:BA:red:ev3dev    pistorms:BB:red:ev3dev
pistorms:BA:blue:ev3dev   pistorms:BB:blue:ev3dev
pistorms:BA:green:ev3dev  pistorms:BB:green:ev3dev



Suppose I want to use uleds on my desktop to simulate my Raspberry Pi. 
If we restrict the name to the LEDs class convention of 
device:color:function, then I can't do this. led0 does not follow the 
convention at all. The other do follow the convention, but only if we 
allow that the device portion of the name can also include ':'.

It's too late, the crazy names already exist.