From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261656AbVFQMrp (ORCPT ); Fri, 17 Jun 2005 08:47:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261952AbVFQMro (ORCPT ); Fri, 17 Jun 2005 08:47:44 -0400 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:23004 "EHLO amd.ucw.cz") by vger.kernel.org with ESMTP id S261656AbVFQMrT (ORCPT ); Fri, 17 Jun 2005 08:47:19 -0400 Date: Fri, 17 Jun 2005 14:47:01 +0200 From: Pavel Machek To: Reiner Sailer Cc: LKLM , LSM , Kylene Hall , Emily Rattlif , Tom Lendacky , Greg KH , Chris Wright , Reiner Sailer Subject: Re: [PATCH] 2 of 5 IMA: documentation patch Message-ID: <20050617124701.GA12863@elf.ucw.cz> References: <1118845859.2269.17.camel@secureip.watson.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1118845859.2269.17.camel@secureip.watson.ibm.com> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi! > --- linux-2.6.12-rc6-mm1_orig/Documentation/ima/integrity_measurements.txt 1969-12-31 19:00:00.000000000 -0500 > +++ linux-2.6.12-rc6-mm1-ima/Documentation/ima/integrity_measurements.txt 2005-06-14 16:25:05.000000000 -0400 > @@ -0,0 +1,87 @@ > +The IBM Integrity Measurement Architecture (IMA) offers means to > +securely identify the software that was loaded into a system run-time > +since the last reboot. The IMA builds the information necessary to > +identify the loaded software and provides the basis for services to > +build on top of such information. However, it does not include any > +means that would enable remote parties to extract the information > +itself. > + > +Guarantees: IMA offers "software load-guarantees" in that > +identification of all loaded software is guaranteed to be reflected in > +measurement data and protected in a hardware TPM security chip (if > +available). IMA is non-intrusive and neither disturbs the system, nor > +prevents the system from any actions. However, if running in real > +mode, when the TPM chip is not accessible IMA might require the system > +not to start (for security guarantee reasons). > + > +Limitations: IMA does not detect corruption of software once it is > +loaded into main memory. Instead, it indicates known vulnerabilities > +in such software (e.g., buffer overflow) by securely identifying the > +software at load-time. Only executable files (binaries, libraries, > +kernel modules) are measured by default. However, IMA offers a > +ima file system that enables applications to instruct the kernel to > +measure files that they have opened (/ima/measurereq). > + > +Assumed usage: Verify system installed software configurations and > +system run-time integrity from a secure management location. You say that you must panic system if TPM is not acessible during bootup. That smells just plain wrong. If I want to trick secure managment point, what prevents me from booting kernel in "test" mode, and then lie about it? > +Some of our work shows that IMA is very useful to detect Rootkit > +exploits that totally take over the software of a Linux system but > +cannot hide themselves from contributing to the TPM aggregate and this > +will be detectable from a non-corrupted platform. While the corrupted > +system might not show the Rootkit, a remote party can securely > +identify known bad or unknown software having been loaded into the > +system. No; with your current system, it only means I may not place my rootkit into executable file. I can still place my evil rootkit into shell script and/or config file. Pavel -- teflon -- maybe it is a trademark, but it should not be.