From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755103Ab3KUS6b (ORCPT ); Thu, 21 Nov 2013 13:58:31 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:47971 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754527Ab3KUS6a (ORCPT ); Thu, 21 Nov 2013 13:58:30 -0500 Date: Thu, 21 Nov 2013 10:58:28 -0800 From: Greg KH To: Vivek Goyal Cc: linux-kernel@vger.kernel.org, kexec@lists.infradead.org, ebiederm@xmission.com, hpa@zytor.com, mjg59@srcf.ucam.org Subject: Re: [PATCH 0/6] kexec: A new system call to allow in kernel loading Message-ID: <20131121185828.GA17070@kroah.com> References: <1384969851-7251-1-git-send-email-vgoyal@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1384969851-7251-1-git-send-email-vgoyal@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 20, 2013 at 12:50:45PM -0500, 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. Very good stuff, thanks for working on this. How have you been testing this on the userspace side? Are there patches to kexec, or are you just using a small test program with the new syscall? I'll comment on the patches separately. greg k-h