From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261607AbUL3KDL (ORCPT ); Thu, 30 Dec 2004 05:03:11 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261608AbUL3KDL (ORCPT ); Thu, 30 Dec 2004 05:03:11 -0500 Received: from canuck.infradead.org ([205.233.218.70]:27659 "EHLO canuck.infradead.org") by vger.kernel.org with ESMTP id S261607AbUL3KDH (ORCPT ); Thu, 30 Dec 2004 05:03:07 -0500 Subject: Re: Stack guards, PaX and such From: Arjan van de Ven To: David Jacoby Cc: linux-kernel@vger.kernel.org In-Reply-To: <41D3C66F.5070909@outpost24.com> References: <41D3C66F.5070909@outpost24.com> Content-Type: text/plain Date: Thu, 30 Dec 2004 11:02:56 +0100 Message-Id: <1104400976.4170.7.camel@laptopd505.fenrus.org> Mime-Version: 1.0 X-Mailer: Evolution 2.0.2 (2.0.2-3) Content-Transfer-Encoding: 7bit X-Spam-Score: 4.1 (++++) X-Spam-Report: SpamAssassin version 2.63 on canuck.infradead.org summary: Content analysis details: (4.1 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 0.3 RCVD_NUMERIC_HELO Received: contains a numeric HELO 1.1 RCVD_IN_DSBL RBL: Received via a relay in list.dsbl.org [] 2.5 RCVD_IN_DYNABLOCK RBL: Sent directly from dynamic IP address [80.57.133.107 listed in dnsbl.sorbs.net] 0.1 RCVD_IN_SORBS RBL: SORBS: sender is listed in SORBS [80.57.133.107 listed in dnsbl.sorbs.net] X-SRS-Rewrite: SMTP reverse-path rewritten from by canuck.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2004-12-30 at 10:12 +0100, David Jacoby wrote: > Hi everyone! > > I hope you had an nice and relaxing x-mas and are ready for a nice new > years eve. > I just have a little question, i really dont if this has ben discussed > before, but if it > has im really sorry. are you talking about making the userspace stack not executable or the kernel stacks? With NX, userspace stacks already are not executable (and if you have a cpu without NX you can use the execshield patches or PaX) As for kernel stacks, well, with NX those are not executable either, and to be honest, I can't remember the last time there was a user exploitable kernel stack buffer overflow. So if your assertion is that those are a common type of security problem, I disagree with you. (One of the underlying causes is that the kernel stack is only really small so it's relatively uncommon and deprecated to put arrays on the kernel stack)