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

From: Pavel Machek
Date: Tue Jun 19 2007 - 11:26:18 EST


Hi!

> > In a smaller scale example, I want to share some files with a friend. I
> > can't be bothered to set up a proper access control system, so I just mv
> > the files to ~crispin/public_html/lookitme and in IRC say "get it now,
> > going away in 10 minutes" and then move it out again. Yes, you can
> > manually address this by running "restorecon ~crispin/public_html". But
> > AA does this automatically without having to run any commands.
> If you share ~crispin/public_html/lookitme by making a hard link,
> does relabeling approach work?
> I thought SELinux allows only one label for one file.
> If AA (on the top of SELinux) tries to allow different permissions to
> ~crispin/public_html/lookitme and its original location,
> either one of two pathnames won't be accessible as intended, will it?

Yes, that's a bug/feature in AA. No, selinux will not be able to emulate that
bug/feature. Yes, it is dangerous, as it makes AA mostly useless on
multiuser machines.

(ln /etc/shadow /tmp is something any user can do, and all you need is
to exploit any daemon with access to /tmp).
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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