From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755746Ab3AKVEN (ORCPT ); Fri, 11 Jan 2013 16:04:13 -0500 Received: from terminus.zytor.com ([198.137.202.10]:52090 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755636Ab3AKVEM (ORCPT ); Fri, 11 Jan 2013 16:04:12 -0500 Message-ID: <50F07E2D.6010602@zytor.com> Date: Fri, 11 Jan 2013 13:03:41 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: Vivek Goyal CC: "Eric W. Biederman" , Konrad Rzeszutek Wilk , Daniel Kiper , "xen-devel@lists.xensource.com" , Andrew Cooper , "x86@kernel.org" , "kexec@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "virtualization@lists.linux-foundation.org" , "mingo@redhat.com" , Jan Beulich , "maxim.uvarov@oracle.com" , "tglx@linutronix.de" , David Howells Subject: Re: [Xen-devel] [PATCH v3 00/11] xen: Initial kexec/kdump implementation References: <50E41973.9050705@citrix.com> <20130104142257.GC3346@host-192-168-1-59.local.net-space.pl> <50E6F81D02000078000B3245@nat28.tlf.novell.com> <20130104170751.GB3472@host-192-168-1-59.local.net-space.pl> <20130104191146.GC6721@phenom.dumpdata.com> <20130107123404.GA2927@host-192-168-1-59.local.net-space.pl> <20130107162018.GJ3219@phenom.dumpdata.com> <87ehhsqrpr.fsf@xmission.com> <20130111165506.GD25620@phenom.dumpdata.com> <87k3rjtqi7.fsf@xmission.com> <20130111205232.GC17126@redhat.com> In-Reply-To: <20130111205232.GC17126@redhat.com> X-Enigmail-Version: 1.5 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/11/2013 12:52 PM, Vivek Goyal wrote: > > Eric, > > In a private conversation, David Howells suggested why not pass kernel > signature in a segment to kernel and kernel can do the verification. > > /sbin/kexec signature is verified by kernel at exec() time. Then > /sbin/kexec just passes one signature segment (after regular segment) for > each segment being loaded. The segments which don't have signature, > are passed with section size 0. And signature passing behavior can be > controlled by one new kexec flag. > > That way /sbin/kexec does not have to worry about doing any verification > by itself. In fact, I am not sure how it can do the verification when > crypto libraries it will need are not signed (assuming they are not > statically linked in). > > What do you think about this idea? > A signed /sbin/kexec would realistically have to be statically linked, at least in the short term; otherwise the libraries and ld.so would need verification as well. Now, that *might* very well have some real value -- there are certainly users out there who would very much want only binaries signed with specific keys to get run on their system. -hpa