From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751425AbcFVX55 (ORCPT ); Wed, 22 Jun 2016 19:57:57 -0400 Received: from mail-pf0-f193.google.com ([209.85.192.193]:36769 "EHLO mail-pf0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750943AbcFVX54 (ORCPT ); Wed, 22 Jun 2016 19:57:56 -0400 Subject: Re: [PATCH v3 0/9] kexec_file_load implementation for PowerPC To: Thiago Jung Bauermann References: <1466538521-31216-1-git-send-email-bauerman@linux.vnet.ibm.com> <20160622232946.793d6c04@350D> <2895031.4C8tZ3BP2G@hactar> Cc: linuxppc-dev@lists.ozlabs.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org From: Balbir Singh Message-ID: <576B25FF.1010307@gmail.com> Date: Thu, 23 Jun 2016 09:57:51 +1000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.8.0 MIME-Version: 1.0 In-Reply-To: <2895031.4C8tZ3BP2G@hactar> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 23/06/16 03:02, Thiago Jung Bauermann wrote: > Hello Balbir, > Hi Thiago >>> 3. have IMA pass-on its event log (where integrity measurements are >>> >>> registered) accross kexec to the second kernel, so that the event >>> history is preserved. >> >> OK.. and this is safe? Do both the kernels need to be signed by the >> same certificate? > > They don't. The integrity of the event log (assuming that is what you mean > by "this" in "this is safe") is guaranteed by the TPM device. Each event in > the measurement list extends a PCR and records its PCR value. It is > cryptographically guaranteed that if you replay the PCR extends recorded in > the event log and in the end of the process they match the current PCR > values in the TPM device, then that event log is correct. What I meant was how does the new kernel know that the old kernel did not cheat while passing on the values? I presume because we trust that kernel via a signature. and How do we know the new kernel is safe to load - I guess via a signature that the new kernel is signed with (assuming it is present in the key ring). Balbir Singh