From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andi Kleen <andi@firstfloor.org>
Subject: Re: [PATCH] Security: Add prctl(PR_{GET,SET}_NETWORK) interface.
Date: Wed, 16 Dec 2009 16:59:38 +0100
Message-ID: <20091216155938.GG15031@basil.fritz.box>
References: <1260977452-2334-1-git-send-email-michael@laptop.org> <1260977565-2379-1-git-send-email-michael@laptop.org>
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Cc: Ulrich Drepper <drepper@gmail.com>, linux-kernel@vger.kernel.org,
	netdev@vger.kernel.org, linux-security-module@vger.kernel.org,
	Andi Kleen <andi@firstfloor.org>, David Lang <david@lang.hm>,
	Oliver Hartkopp <socketcan@hartkopp.net>,
	Alan Cox <alan@lxorguk.ukuu.org.uk>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	Valdis Kletnieks <Valdis.Kletnieks@vt.edu>,
	Bryan Donlan <bdonlan@gmail.com>,
	Evgeniy Polyakov <zbr@ioremap.net>,
	"C. Scott Ananian" <cscott@cscott.net>,
	James Morris <jmorris@namei.org>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Bernie Innocenti <bernie@codewiz.org>,
	Mark Seaborn <mrs@mythic-beasts.com>
To: Michael Stone <michael@laptop.org>
Return-path: <linux-kernel-owner+glk-linux-kernel-3=40m.gmane.org-S933681AbZLPP7o@vger.kernel.org>
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On Wed, Dec 16, 2009 at 10:32:43AM -0500, Michael Stone wrote:
> Daniel Bernstein has observed [1] that security-conscious userland processes
> may benefit from the ability to irrevocably remove their ability to create,
> bind, connect to, or send messages except in the case of previously connected
> sockets or AF_UNIX filesystem sockets. We provide this facility by implementing
> support for a new prctl(PR_SET_NETWORK) flag named PR_NETWORK_OFF.
> 
> This facility is particularly attractive to security platforms like OLPC
> Bitfrost [2] and to isolation programs like Rainbow [3] and Plash [4].

What would stop them from ptracing someone else running under the same
uid who still has the network access? If you ptrace you can do
arbitary system calls.

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only.