Re: [PATCH] Input: uinput - fix crash when mixing old and new init style

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

On Wed, Feb 01, 2017 at 09:49:25AM +0100, Benjamin Tissoires wrote:
> On Jan 31 2017 or thereabouts, Dmitry Torokhov wrote:
> > If user tries to initialize uinput device mixing old and new style
> > initialization (i.e. using old UI_SET_ABSBIT instead of UI_ABS_SETUP,
> > we forget to allocate input->absinfo and will crash when trying to send
> > absolute events:
> > 
> >         ioctl(ui, UI_DEV_SETUP, &us);
> >         ioctl(ui, UI_SET_EVBIT, EV_ABS);
> >         ioctl(ui, UI_SET_ABSBIT, ABS_X);
> >         ioctl(ui, UI_SET_ABSBIT, ABS_Y);
> >         ioctl(ui, UI_DEV_CREATE, 0);
> 
> Shouldn't we prevent completely the mix of the 2 versions? If the user
> used UI_DEV_SETUP, we should probably prevent the use of UI_SET_ABSBIT
> afterwards, or at least warn it somehow.

Why? If user does not wish to set up parameters of an axis then just
using UI_SET_ABSBIT is fine. In fact, I think it would be weird if we
allowed all UI_SET_*BIT except for ABS.

> 
> But the patch in itself doesn't hurt, so:
> Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

Thanks.

-- 
Dmitry