Re: Proposal: Generalized Security Framework for X server

On Thu, 2004-03-04 at 05:52, Ely Levy wrote:
> Hey,
> I started to look at X security few weeks ago and I wondered
> how you solved few problems.
> did you handle things like someone stealing the X image by reading the fb
> directly?

Protecting the fb would be the job of the operating system.  The work
I'm doing only concerns things like background-None windows and image
grabbing (things you can do through X protocol requests).

> does it handle the fact that the magic cookies goes over the net as plain
> text?

This is also outside the scope of my work; I'm not changing the
authentication mechanism.

> I was thinking about private/public key sort of thing.
> (altough it seems ssh -X does some of the work of encrypting).
> There is also the very common use of nfs home directory which makes the
> cookies very easily obtained does the extention solves that by using
> access levels?

I'm just taking the hooks that the Security extension already has and
providing a new interface to them so that other projects can use them.  

The original authors of the Security extension envisioned an extensible
model, but things never progressed past their simple trusted/untrusted 
model, and the Security extension has fallen into disuse.

The problems you describe, protecting the network traffic  the
.Xauthority file, and the framebuffer, are indeed issues but they are
better addressed outside the X server.

> hope my questions are not too silly:)
> 

Not at all!


> Ely
> 
> 
> On Thu, 3 Mar 2004, Eamon Walsh wrote:
> 
> > xserver developers:
> >
> > I have been working on a server extension which replaces the old
> > "Security" extension with a framework of callbacks and security state,
> > similar to the Linux Security Module in the Linux kernel.  The attached
> > proposal describes it in more detail, including code examples.
> >
> > I work for the NSA Security-Enhanced Linux team, and this extension is
> > the foundation upon which we hope to implement SELinux support for X.
> > However, it can be generally used to implement a wide variety of models
> > for access control and auditing.
> >
> > I have been working from the xserver CVS head and am reaching the point
> > where I have usable-but-experimental code.  With list support, I would
> > like to post patches for review.
> >
> > Comments on the proposal?
> >
> > Eamon Walsh
> > National Security Agency
> >
> >
-- 
Eamon Walsh <[email protected]>
National Security Agency