Re: input/eventX permissions, force feedback

From: Dmitry Torokhov
Date: Tue Jul 18 2006 - 08:18:24 EST

Hi Anssi,

On 7/18/06, Anssi Hannula <anssi.hannula@xxxxxxxxx> wrote:
Currently most distributions have /dev/input/event* strictly as 0600
root:root or 0640 root:root. The user logged in will not have rights to
the device, unlike /dev/input/js*, as he could read all passwords from
the keyboard device.

This is a problem, because /dev/input/event* is used for force feedback
and should therefore be user-accessible.

I can think of the following solutions to this problem:

1. Some creative udev rule to chmod /dev/input/event* less strictly when
it has a /dev/input/js* and is thus a gaming device.

2. Some creative udev rule to chmod /dev/input/event* more strictly when
it is a keyboard.

3. Have another force feedback interface also in /dev/input/js*.

You can do it in udev looking either at MODALIAS or at EV and ABS
environment variables. I think it is pretty safe to say that a device
with EV_ABS, EV_FF, ABS_X and ABS_Y is a force-feedback joystick-type
device and not a keyboard.

Another solution would be to relax permissions if user is also console
owner (home box installation).

One thing is for sure - I do not like #3 at all ;)

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