From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755166Ab2KBOgx (ORCPT ); Fri, 2 Nov 2012 10:36:53 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43802 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752788Ab2KBOgt (ORCPT ); Fri, 2 Nov 2012 10:36:49 -0400 Date: Fri, 2 Nov 2012 10:36:03 -0400 From: Vivek Goyal To: Balbir Singh Cc: Matthew Garrett , Mimi Zohar , "Eric W. Biederman" , Khalid Aziz , kexec@lists.infradead.org, horms@verge.net.au, Dave Young , "H. Peter Anvin" , linux kernel mailing list , Dmitry Kasatkin , Roberto Sassu , Kees Cook , Peter Jones Subject: Re: Kdump with signed images Message-ID: <20121102143603.GD3300@redhat.com> References: <20121026023916.GA16762@srcf.ucam.org> <20121026170609.GB24687@redhat.com> <1351276649.18115.217.camel@falcor> <20121101131003.GA14573@redhat.com> <20121101135356.GA15659@redhat.com> <1351780159.15708.17.camel@falcor> <20121101144304.GA15821@redhat.com> <20121101145225.GB10269@srcf.ucam.org> <20121102132318.GA3300@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 Fri, Nov 02, 2012 at 07:59:15PM +0530, Balbir Singh wrote: > On Fri, Nov 2, 2012 at 6:53 PM, Vivek Goyal wrote: > > On Thu, Nov 01, 2012 at 02:52:25PM +0000, Matthew Garrett wrote: > >> On Thu, Nov 01, 2012 at 10:43:04AM -0400, Vivek Goyal wrote: > >> > >> > So I think this does satisfy the requirement matthew specified. Isn't it? > >> > Matthew, what do you think? > >> > >> Sure, if you can ensure that. You'll need to figure out how to get the > >> build system to sign the userspace binaries and you'll need to ensure > >> that they're statically linked and don't dlopen anything (including the > >> nsswitch modules), but otherwise that should work. > >> > > > > [ CC peter jones ] > > > > Ok, so even if we build kexec-tools statically with glibc, we have the > > issue of name service switch modules. glibc will still do dlopen on > > these modules. So what are options now. > > > > - Sign glibc and associated shared libraries. Do not allow unsigned > > shared library to dynamically link with signed executable. > > > > - Peter mentioned that work with uClibc for kexec-tools. > > > > I personally think that however hard it is but first option sounds like > > a long term solution. We might have more user space processes which > > we might have to trust a generic solution will help with that. For example, > > we might have to sign and trust qemu at some point of time. > > > > Are there other ways of handing glibc issue? > > > > Have you seen http://sourceware.org/glibc/wiki/FAQ - "Even statically > linked programs need some shared libraries which is not acceptable for > me. What can I do?" Probably, worth trying. Yes I have seen this. IIUC, it says that build libc with -enable-static-nss and then individual programs need to statically build against the nss modules program will use. I think building libc with -enable-static-nss part will be unacceptable for general server as other programs would like to make use of the existing nss functionality. Thanks Vivek