Re: Xwindows security?

[mccoy () io com (Jim McCoy)]

> From: Jon Peatfield <J.S.Peatfield () amtp cam ac uk>
[...]
> I'd like to add a new authentication mechanism to X which uses Ident (TAP, 
> RFC-931 etc), to check that a user is permitted.  e.g. a server is given a 
> list of allowed user/machine pairs by a program like xhost:
> [which it checks using ident for incoming connections...]

This pretty much reduces down to the same problem that xhost has.  I have
several program that will fake my ident ID to be whatever I want it to be.
The advantge of xauth over xhost is that it requires possession of a
discrete piece of information which, in theory, cannot be easily faked.  If
I have physical access the host I can change my username, run an ident
faker, or otherwise compromise any security mechanism which relies upon the
remote machine to provide the authentication.  You allow for a bit more
granularity in access control in a trusted (and trusting) environment, but
if you already have this level of trust xhost is good enough anyway because
all you really need to do is prevent someone from accidentally popping up a
window on your display...

jim