Subject: Re: wsmux inject
To: Iain Hibbert <>
From: Steven M. Bellovin <>
List: tech-kern
Date: 03/14/2006 18:48:53
On Tue, 14 Mar 2006 23:17:12 +0000 (GMT), Iain Hibbert
<> wrote:

> On Wed, 15 Mar 2006, Valeriy E. Ushakov wrote:
> > With current code you can inject events into the mux for processes
> > that read from the mux (as your hexdump exepriment demonstrates),
> > e.g. you should be able to inject events for x server to read from the
> > mux, but you cannot inject "terminal input" for /dev/ttyE*
> Hm, I see..  (vaguely :)
> > To feed terminal input from user space, you need a way to inject raw
> > scancodes that need to end up being passed to wskbd_input.
> Well, it seems that I could do that quite simply by creating a
> WSKBDIO_INJECT ioctl in wskbd_displayioctl() though thats a bit of a
> bodge..
> I'm thinking it would likely be better to make a pseudo-device that would
> attach as a wsbkdN when necessary, not sure if that will work as planned.

Have the ability to inject keyboard and mouse events, though useful for
many purposes, poses serious security issues that should be thought
through.  The issue is ancient; see or about TIOCSTI, for example,
or the discussion about allowSendEvents in the xterm man page.

From that perspective, requiring a separate driver is a good thing,
since it's then easy to exclude from the system.

		--Steven M. Bellovin,