Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754852Ab1EaNlP (ORCPT ); Tue, 31 May 2011 09:41:15 -0400 Received: from lennier.cc.vt.edu ([198.82.162.213]:42345 "EHLO lennier.cc.vt.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751038Ab1EaNlN (ORCPT ); Tue, 31 May 2011 09:41:13 -0400 X-Mailer: exmh version 2.7.2 01/07/2005 with nmh-1.3-dev To: Mimi Zohar Cc: Pavel Machek , David Safford , Casey Schaufler , Andrew Morton , linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, James Morris , Greg KH , Dmitry Kasatkin Subject: Re: [PATCH v5 00/21] EVM In-Reply-To: Your message of "Tue, 31 May 2011 08:05:08 EDT." <1306843508.3181.94.camel@localhost.localdomain> From: Valdis.Kletnieks@vt.edu References: <1305557115-15652-1-git-send-email-zohar@linux.vnet.ibm.com> <20110518172552.6d482c7a.akpm@linux-foundation.org> <20110526060842.GA13933@localhost.ucw.cz> <4DDE80FE.7010005@schaufler-ca.com> <1306433514.24986.26.camel@localhost.localdomain> <20110526183849.GA4563@ucw.cz> <1306439347.3092.89.camel@localhost.localdomain> <20110526201725.GC15959@elf.ucw.cz> <1306518351.24986.102.camel@localhost.localdomain> <20110529065818.GA2122@elf.ucw.cz> <1306843508.3181.94.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="==_Exmh_1306849210_2772P"; micalg=pgp-sha1; protocol="application/pgp-signature" Content-Transfer-Encoding: 7bit Date: Tue, 31 May 2011 09:40:10 -0400 Message-ID: <30374.1306849210@turing-police.cc.vt.edu> X-Mirapoint-Received-SPF: 198.82.161.152 auth3.smtp.vt.edu Valdis.Kletnieks@vt.edu 2 pass X-Mirapoint-IP-Reputation: reputation=neutral-1, source=Fixed, refid=n/a, actions=MAILHURDLE SPF TAG X-Junkmail-Status: score=10/50, host=zidane.cc.vt.edu X-Junkmail-Signature-Raw: score=unknown, refid=str=0001.0A020209.4DE4EFBF.0041,ss=1,fgs=0, ip=71.62.120.129, so=2010-07-22 22:03:31, dmn=2009-09-10 00:05:08, mode=single engine X-Junkmail-IWF: false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1414 Lines: 38 --==_Exmh_1306849210_2772P Content-Type: text/plain; charset=us-ascii On Tue, 31 May 2011 08:05:08 EDT, Mimi Zohar said: > For files that you don't expect to change, such as ELF executables, you > probably could use the immutable flag, but using a digital signature > provides authenticity as well, which the immutable flag does not > provide. The problem with 'chattr +i' is that if an attacker gets root, they can 'chattr -i' and start scribbling. I've never personally trusted it for anything more than protecting against overexuberant root processes that forget to obey file permissions (like the DHCP script that keeps insisting on removing all the IPv6 nameservers out of my /etc/resolv.conf even when it's mode 444). As you noted, digitally signing the executables with a key not found on the system raises the bar substantially.. --==_Exmh_1306849210_2772P Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) Comment: Exmh version 2.5 07/13/2001 iD8DBQFN5O+6cC3lWbTT17ARArq7AJ9cBCkQWS5EI4QYkILDJYaRY7anjwCcCspI rEqXlf75gbDQVqXS+Tb4+XA= =nocB -----END PGP SIGNATURE----- --==_Exmh_1306849210_2772P-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/