Re: [PATCH v3] Input: uinput - add new UINPUT_DEV_SETUP and UI_ABS_SETUP ioctl

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

Hi Benjamin,

On Tue, Aug 25, 2015 at 11:12:59AM -0400, Benjamin Tissoires wrote:
> +static int uinput_abs_setup(struct uinput_device *udev,
> +			    struct uinput_setup __user *arg, size_t size)
> +{
> +	struct uinput_abs_setup setup = {};
> +	struct input_dev *dev;
> +
> +	if (size > sizeof(setup))
> +		return -E2BIG;
> +	if (udev->state == UIST_CREATED)
> +		return -EINVAL;
> +	if (copy_from_user(&setup, arg, size))
> +		return -EFAULT;
> +	if (setup.code > ABS_MAX)
> +		return -ERANGE;
> +
> +	dev = udev->dev;
> +
> +	input_alloc_absinfo(dev);
> +	if (!dev->absinfo)
> +		return -ENOMEM;
> +
> +	set_bit(setup.code, dev->absbit);
> +	dev->absinfo[setup.code] = setup.absinfo;
> +
> +	/*
> +	 * We restore the state to UIST_NEW_DEVICE because the user has to call
> +	 * UI_DEV_SETUP in the last place before UI_DEV_CREATE to check the
> +	 * validity of the absbits.
> +	 */

Do we have to be this strict? It seems to me that with the new IOCTLs
you naturally want to use the new ioctl to setup the device, then adjust
various axes and bits and then validate everything.

Thanks.

-- 
Dmitry