Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758512Ab3IHRdA (ORCPT ); Sun, 8 Sep 2013 13:33:00 -0400 Received: from bedivere.hansenpartnership.com ([66.63.167.143]:59759 "EHLO bedivere.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757566Ab3IHRc7 (ORCPT ); Sun, 8 Sep 2013 13:32:59 -0400 Message-ID: <1378661576.2429.16.camel@dabdike.int.hansenpartnership.com> Subject: Re: [PATCH V3 08/11] kexec: Disable at runtime if the kernel enforces module loading restrictions From: James Bottomley To: Matthew Garrett Cc: Kees Cook , Greg KH , "linux-kernel@vger.kernel.org" , "linux-efi@vger.kernel.org" , "hpa@zytor.com" Date: Sun, 08 Sep 2013 10:32:56 -0700 In-Reply-To: <1378661252.2300.26.camel@x230> References: <1378252218-18798-1-git-send-email-matthew.garrett@nebula.com> <1378252218-18798-9-git-send-email-matthew.garrett@nebula.com> <20130908064027.GA3587@kroah.com> <1378622648.2300.4.camel@x230> <20130908072408.GA5092@kroah.com> <1378660284.2429.11.camel@dabdike.int.hansenpartnership.com> <1378660541.2300.19.camel@x230> <1378660975.2429.14.camel@dabdike.int.hansenpartnership.com> <1378661252.2300.26.camel@x230> Content-Type: text/plain; charset="ISO-8859-15" X-Mailer: Evolution 3.8.5 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1147 Lines: 25 On Sun, 2013-09-08 at 17:27 +0000, Matthew Garrett wrote: > > It's an argument that CAP_SYS_BOOT is too powerful yes, but if you > > recall, I said I keep that one. In the rather lame analogy, what I do > > by giving away CAP_SYS_MODULE and enforcing module signing while keeping > > CAP_SYS_BOOT is allow people into my conservatory to play with the > > plants but not into my house to steal the silver ... saying CAP_SYS_BOOT > > is too powerful doesn't affect that use case because I haven't given > > away CAP_SYS_BOOT. > > Ok, sorry, I had your meaning inverted. Yes, permitting the loading of > signed modules while preventing the use of kexec is a completely > reasonable configuration - so reasonable that it's what this patch > causes the kernel to do automatically. Well, no, it doesn't because with this patch, *I* can't use kexec ... you've just locked me out of my own house. James -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/