From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755408Ab3KVAzi (ORCPT ); Thu, 21 Nov 2013 19:55:38 -0500 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:37919 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753041Ab3KVAzd (ORCPT ); Thu, 21 Nov 2013 19:55:33 -0500 X-SecurityPolicyCheck: OK by SHieldMailChecker v1.8.9 X-SHieldMailCheckerPolicyVersion: FJ-ISEC-20120718-2 Message-ID: <528EAB73.9010700@jp.fujitsu.com> Date: Fri, 22 Nov 2013 09:55:15 +0900 From: HATAYAMA Daisuke User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:24.0) Gecko/20100101 Thunderbird/24.1.1 MIME-Version: 1.0 To: Vivek Goyal CC: linux-kernel@vger.kernel.org, kexec@lists.infradead.org, mjg59@srcf.ucam.org, greg@kroah.com, ebiederm@xmission.com, hpa@zytor.com Subject: Re: [PATCH 0/6] kexec: A new system call to allow in kernel loading References: <1384969851-7251-1-git-send-email-vgoyal@redhat.com> In-Reply-To: <1384969851-7251-1-git-send-email-vgoyal@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org (2013/11/21 2:50), Vivek Goyal wrote: > Current proposed secureboot implementation disables kexec/kdump because > it can allow unsigned kernel to run on a secureboot platform. Intial > idea was to sign /sbin/kexec binary and let that binary do the kernel > signature verification. I had posted RFC patches for this apparoach > here. > > https://lkml.org/lkml/2013/9/10/560 > > Later we had discussion at Plumbers and most of the people thought > that signing and trusting /sbin/kexec is becoming complex. So a > better idea might be let kernel do the signature verification of > new kernel being loaded. This calls for implementing a new system call > and moving lot of user space code in kernel. > > kexec_load() system call allows loading a kexec/kdump kernel and jump > to that kernel at right time. Though a lot of processing is done in > user space which prepares a list of segments/buffers to be loaded and > kexec_load() works on that list of segments. It does not know what's > contained in those segments. > > Now a new system call kexec_file_load() is implemented which takes > kernel fd and initrd fd as parameters. Now kernel should be able > to verify signature of newly loaded kernel. > > This is an early RFC patchset. I have not done signature handling > part yet. This is more of a minimal patch to show how new system > call and functionality will look like. Right now it can only handle > bzImage with 64bit entry point on x86_64. No EFI, no x86_32 or any > other architecture. Rest of the things can be added slowly as need > arises. In first iteration, I have tried to address most common use case > for us. > > Any feedback is welcome. > So, ultimately on this design direction, user-land kexec command someday will no longer be used at all? Or is there any feature you will keep in user-land side? I think it big change if one component in kdump will disappear. -- Thanks. HATAYAMA, Daisuke