From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751468Ab3LJA0C (ORCPT ); Mon, 9 Dec 2013 19:26:02 -0500 Received: from qmta07.emeryville.ca.mail.comcast.net ([76.96.30.64]:41900 "EHLO qmta07.emeryville.ca.mail.comcast.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751123Ab3LJAZ6 (ORCPT ); Mon, 9 Dec 2013 19:25:58 -0500 X-Greylist: delayed 365 seconds by postgrey-1.27 at vger.kernel.org; Mon, 09 Dec 2013 19:25:58 EST Message-ID: <1386634788.24817.46.camel@rhapsody> Subject: Re: [PATCH] kexec: add sysctl to disable kexec From: Khalid Aziz To: Kees Cook Cc: linux-kernel@vger.kernel.org, Matthew Garrett , Rik van Riel , Peter Zijlstra , kexec@lists.infradead.org, Eric Biederman , Andrew Morton , Ingo Molnar , Vivek Goyal , Mel Gorman Date: Mon, 09 Dec 2013 17:19:48 -0700 In-Reply-To: <20131209233829.GA3501@www.outflux.net> References: <20131209233829.GA3501@www.outflux.net> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.6.2-0ubuntu0.1 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 On Mon, 2013-12-09 at 15:38 -0800, Kees Cook wrote: > For general-purpose (i.e. distro) kernel builds it makes sense to build with > CONFIG_KEXEC to allow end users to choose what kind of things they want to do > with kexec. However, in the face of trying to lock down a system with such > a kernel, there needs to be a way to disable kexec (much like module loading > can be disabled). Without this, it is too easy for the root user to modify > kernel memory even when CONFIG_STRICT_DEVMEM and modules_disabled are set. > > Signed-off-by: Kees Cook Giving Sys admins more control to secure their system is a good idea. This addition looks good to me. -- Khalid