linux-kernel - Re: RFC: Network privilege separation.

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Message-ID: <12821.1231785850@turing-police.cc.vt.edu>
Date:	Mon, 12 Jan 2009 13:44:10 -0500
From:	Valdis.Kletnieks@...edu
To:	Alan Cox <alan@...rguk.ukuu.org.uk>
Cc:	Michael Stone <michael@...top.org>,
	Andi Kleen <andi@...stfloor.org>, linux-kernel@...r.kernel.org,
	netdev@...r.kernel.org
Subject: Re: RFC: Network privilege separation.

On Thu, 08 Jan 2009 10:43:05 GMT, Alan Cox said:

> If you have the same uid then you can just use ptrace to drive another
> task with that uid to do the creations for you. Chances are you can also
> attack shared executable files (eg that uids .bashrc)
> 
> That to me says controlling network access is only useful as part of a
> more fine grained and general purpose interface. We already have that
> interface in the form of things like SELinux. We already have systems
> actively using it to control stuff like which ports are accessed by some
> services.

Yes, the network access part *is* something that should be part of a more
general interface.  Having said that, we currently are lacking a way for a
*general user* program to say "I'm all set up, and would like to disavow any
other further resource access (except maybe r/o access as "other" to file
systems)".

It's pretty easy for stuff running as root to play setuid()/capability() games
to throw away access rights.  It's damned hard for mortal users to do it.

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