Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932409AbZLDRya (ORCPT ); Fri, 4 Dec 2009 12:54:30 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932304AbZLDRy3 (ORCPT ); Fri, 4 Dec 2009 12:54:29 -0500 Received: from terminus.zytor.com ([198.137.202.10]:39563 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932295AbZLDRy2 (ORCPT ); Fri, 4 Dec 2009 12:54:28 -0500 Message-ID: <4B194CA1.3070106@zytor.com> Date: Fri, 04 Dec 2009 09:53:37 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.4pre) Gecko/20091014 Fedora/3.0-2.8.b4.fc11 Thunderbird/3.0b4 MIME-Version: 1.0 To: Andi Kleen CC: "Cihula, Joseph" , Pavel Machek , "Wang, Shane" , "Rafael J. Wysocki" , "linux-kernel@vger.kernel.org" , Ingo Molnar , "arjan@linux.intel.com" , "chrisw@sous-sol.org" , "jmorris@namei.org" , "jbeulich@novell.com" , "peterm@redhat.com" Subject: Re: [PATCH] intel_txt: add s3 userspace memory integrity verification References: <4A9CE0B2.5060608@intel.com> <4ABF2B50.6070106@intel.com> <20091004185801.GC1378@ucw.cz> <037F493892196B458CD3E193E8EBAD4F01F03277DF@pdsmsx502.ccr.corp.intel.com> <20091204081933.GE1540@ucw.cz> <4F65016F6CB04E49BFFA15D4F7B798D9AEDDD4C5@orsmsx506.amr.corp.intel.com> <20091204171333.GS18989@one.firstfloor.org> In-Reply-To: <20091204171333.GS18989@one.firstfloor.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1112 Lines: 29 On 12/04/2009 09:13 AM, Andi Kleen wrote: >>> >>> So no, you did not audit do_suspend_lowlevel to make sure it does not >>> follow function pointers. Bad. >> >> We aren't aware of any code or data used by the resume path that is outside of the tboot-MAC'ed regions above--if you can point out any then we will gladly address them. > > Code coverage is not enough, you need data coverage too. If someone > modifies kernel data it's typically easy to subvert code as a next step. > The only function pointers that are invoked on the do_suspend_lowlevel path are some paravirt_crap pointers, but those are located inside kernel static data. This is not to say that this isn't a new constraint, and should be documented, and checked ahead of time... -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf. -- 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/