Date: Tue, 19 Jun 2007 15:25:55 +0000
From: Pavel Machek <pavel@ucw.cz>
To: Tetsuo Handa <from-lsm@I-love.SAKURA.ne.jp>
Cc: crispin@novell.com, linux-kernel@vger.kernel.org,
       linux-security-module@vger.kernel.org
Subject: Re: [AppArmor 39/45] AppArmor: Profile loading and manipulation,pathname matching
Message-ID: <20070619152555.GB5127@ucw.cz>
References: <466C303E.5010304@novell.com> <20070615165054.GA11345@kroah.com> <20070615200623.GA2616@elf.ucw.cz> <20070615211157.GB7337@kroah.com> <46732124.80509@novell.com> <200706160948.FEH12774.MTtPGSNN@I-love.SAKURA.ne.jp>
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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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