Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756878AbZFCSwD (ORCPT ); Wed, 3 Jun 2009 14:52:03 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754476AbZFCSvy (ORCPT ); Wed, 3 Jun 2009 14:51:54 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:52563 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754550AbZFCSvx (ORCPT ); Wed, 3 Jun 2009 14:51:53 -0400 Date: Wed, 3 Jun 2009 11:50:16 -0700 (PDT) From: Linus Torvalds X-X-Sender: torvalds@localhost.localdomain To: "Larry H." cc: Alan Cox , Christoph Lameter , linux-mm@kvack.org, Rik van Riel , 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) In-Reply-To: Message-ID: References: <20090530230022.GO6535@oblivion.subreption.com> <20090531022158.GA9033@oblivion.subreption.com> <20090602203405.GC6701@oblivion.subreption.com> <20090603182949.5328d411@lxorguk.ukuu.org.uk> <20090603180037.GB18561@oblivion.subreption.com> <20090603183939.GC18561@oblivion.subreption.com> User-Agent: Alpine 2.01 (LFD 1184 2008-12-16) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1156 Lines: 32 On Wed, 3 Jun 2009, Linus Torvalds wrote: > > That means that you've already by-passed all the main security. It's thus > by definition less common than attack vectors like buffer overflows that > give you that capability in the first place. Btw, you obviously need to then _also_ pair it with some as-yet-unknown case of kernel bug to get to that NULL pointer (or zero-sized-alloc pointer) problem. You _also_ seem to be totally ignoring the fact that we already _do_ protect against NULL pointers by default. So I really don't see why you're making a big deal of this. It's as if you were talking about us not randomizing the address space - sure, you can turn it off, but so what? We do it by default. So it boils down to: - NULL pointers already cannot be in mmap memory (unless a distro has done something wrong - outside of the kernel) - What's your beef? Let it go, man. Linus -- 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/