Re: Xwindows security?

[bf () morgan com (Benjamin Fried)]

> > > > > "wam" == William McVey <wam () cs purdue edu> writes:

    wam> Benjamin Fried wrote:

    Ben> Xhost actually has one advantage, of a sort, over xauth: users
    Ben> of xhost can grant access, and later take that access away.

    wam> You want to be very careful in assuming that because you type
    wam> 'xhost -' that your vulnerability goes away.  All clients (like
    wam> xkey) started when the authority was off are still connected
    wam> and are potentially dangerous.  Additionally, clients (like
    wam> xcrowbar) can be started when no authority is in place that
    wam> turns off the authority mechanisms altogether, thus making the
    wam> 'xhost -' a moot point.

That's a good point.  I really wasn't trying to be an advocate for
xhost, though.  I was pointing out that the xhost model allows for
revocation of access, and xauth (at least when using MIT-MAGIC-COOKIE
access control) does not permit revocation of a user's access.  As you
explain, xhost's ability to revoke access is flawed; however, no such
capability exists at all with MIT-MAGIC-COOKIE.

> From what I've read, X11R6's MIT-KERBEROS-5 authorization seems much
better: it lets the user enable and disable access on a per-user basis,
provided you're all running Kerberos 5.  Now if only our vendor(s) supported
R6!

Ben