Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758451AbZFCQhm (ORCPT ); Wed, 3 Jun 2009 12:37:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755275AbZFCQhd (ORCPT ); Wed, 3 Jun 2009 12:37:33 -0400 Received: from mx2.redhat.com ([66.187.237.31]:37297 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754923AbZFCQhc (ORCPT ); Wed, 3 Jun 2009 12:37:32 -0400 Message-ID: <4A26A689.1090300@redhat.com> Date: Wed, 03 Jun 2009 12:36:25 -0400 From: Rik van Riel Organization: Red Hat, Inc User-Agent: Thunderbird 2.0.0.17 (X11/20080915) MIME-Version: 1.0 To: "Larry H." CC: Christoph Lameter , Stephen Smalley , Linus Torvalds , linux-mm@kvack.org, Alan Cox , linux-kernel@vger.kernel.org, pageexec@freemail.hu Subject: Re: Security fix for remapping of page 0 (was [PATCH] Change ZERO_SIZE_PTR to point at unmapped space) References: <20090530192829.GK6535@oblivion.subreption.com> <20090530230022.GO6535@oblivion.subreption.com> <20090531022158.GA9033@oblivion.subreption.com> <20090602203405.GC6701@oblivion.subreption.com> <1244041914.12272.64.camel@localhost.localdomain> <20090603162831.GF6701@oblivion.subreption.com> In-Reply-To: <20090603162831.GF6701@oblivion.subreption.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1046 Lines: 28 Larry H. wrote: > Christopher, crippling the system is truly not the way to fix this. > There are many legitimate users of private|fixed mappings at 0. In > addition, if you want to go ahead and break POSIX, at least make sure > your patch closes the loophole. I suspect there aren't many at all, and restricting them through SELinux may be enough to mitigate the risk. > If SELinux isn't present, that's not useful. If mmap_min_addr is > enabled, that still won't solve what my original, utterly simple patch > fixes. Would anybody paranoid run their system without SELinux? > The patch provides a no-impact, clean solution to prevent kmalloc(0) > situations from becoming a security hazard. Nothing else. True, the changes in your patch only affect a few code paths. -- All rights reversed. -- 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/