Re: [AppArmor 39/45] AppArmor: Profile loading and manipulation, pathname matching

[John Johansen <jjohansen@suse.de>]

On Thu, Jun 21, 2007 at 04:59:54PM -0400, Stephen Smalley wrote:
> On Thu, 2007-06-21 at 21:54 +0200, Lars Marowsky-Bree wrote:
> > On 2007-06-21T15:42:28, James Morris <jmorris@namei.org> wrote:
> > 
> 
> > And now, yes, I know AA doesn't mediate IPC or networking (yet), but
> > that's a missing feature, not broken by design.
> 
> The incomplete mediation flows from the design, since the pathname-based
> mediation doesn't generalize to cover all objects unlike label- or
> attribute-based mediation.  And the "use the natural abstraction for
> each object type" approach likewise doesn't yield any general model or
> anything that you can analyze systematically for data flow.
> 
No the "incomplete" mediation does not flow from the design.  We have
deliberately focused on doing the necessary modifications for pathname
based mediation.  The IPC and network mediation are a wip.

We have never claimed to be using pathname-based mediation IPC or networking.
The "natural abstraction" approach does generize well enough and will
be analyzable.

> The emphasis on never modifying applications for security in AA likewise
> has an adverse impact here, as you will ultimately have to deal with
> application mediation of access to their own objects and operations not
> directly visible to the kernel (as we have already done in SELinux for
> D-BUS and others and are doing for X).  Otherwise, your "protection" of
> desktop applications is easily subverted.
> 
yes of course, we realize that dbus and X must be trusted applications,
this to will happen.  But it will happen piece meal, something about
releasing early and often comes to mind.

> > > You might define this as a non-technical issue, but the fact that AppArmor 
> > > simply does not and can not work is a fairly significant consideration, I 
> > > would imagine.
> > 
> > If I restrict my Mozilla to not access my on-disk mail folder, it can't
> > get there. (Barring bugs in programs which Mozilla is allowed to run
> > unconfined, sure.)
> 
> Um, no.  It might not be able to directly open files via that path, but
> showing that it can never read or write your mail is a rather different
> matter.
> 
Actually it can be analyzed and shown.  It is ugly to do and we
currently don't have a tool capable of doing it, but it is possible.

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