From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with ESMTP id AB3325F0003 for ; Wed, 3 Jun 2009 12:13:19 -0400 (EDT) Date: Wed, 3 Jun 2009 17:14:09 +0100 From: Alan Cox Subject: Re: Security fix for remapping of page 0 (was [PATCH] Change ZERO_SIZE_PTR to point at unmapped space) Message-ID: <20090603171409.5c60422c@lxorguk.ukuu.org.uk> In-Reply-To: References: <20090530192829.GK6535@oblivion.subreption.com> <20090530230022.GO6535@oblivion.subreption.com> <20090531022158.GA9033@oblivion.subreption.com> <20090602203405.GC6701@oblivion.subreption.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Linus Torvalds Cc: Christoph Lameter , "Larry H." , linux-mm@kvack.org, Rik van Riel , linux-kernel@vger.kernel.org, pageexec@freemail.hu List-ID: > It defaults to 64kB in at least the x86 defconfig files, but to 0 in the > Kconfig defaults. Also, for some reason it has a "depends on SECURITY", > which means that if you just default to the old-style unix security you'll > lose it. > > So there are several ways to disable it by mistake. I don't know what > distros do. Fedora at least uses SELinux to manage it. You need some kind of security policy engine running as a few apps really need to map low space (mostly for vm86) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org