From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262935AbUCXBdP (ORCPT ); Tue, 23 Mar 2004 20:33:15 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262957AbUCXBdP (ORCPT ); Tue, 23 Mar 2004 20:33:15 -0500 Received: from cpe-24-221-190-179.ca.sprintbbd.net ([24.221.190.179]:38584 "EHLO myware.akkadia.org") by vger.kernel.org with ESMTP id S262935AbUCXBdO (ORCPT ); Tue, 23 Mar 2004 20:33:14 -0500 Message-ID: <4060E24C.9000507@redhat.com> Date: Tue, 23 Mar 2004 17:20:12 -0800 From: Ulrich Drepper Organization: Red Hat, Inc. User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7b) Gecko/20040322 X-Accept-Language: en-us, en MIME-Version: 1.0 To: davidm@hpl.hp.com CC: linux-kernel@vger.kernel.org Subject: Re: Non-Exec stack patches References: <20040323231256.GP4677@tpkurt.garloff.de> <20040323154937.1f0dc500.akpm@osdl.org> <20040324002149.GT4677@tpkurt.garloff.de> <16480.55450.730214.175997@napali.hpl.hp.com> In-Reply-To: <16480.55450.730214.175997@napali.hpl.hp.com> X-Enigmail-Version: 0.83.5.0 X-Enigmail-Supports: pgp-inline, pgp-mime Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org David Mosberger wrote: > I guess I never quiet understood why an entire program header is > needed for this, but that's just me. This just means you haven't looked at the problem. First, the ELF bits are limited and very crowded on some archs. There is no central assignment so conflicts will happen. And one single bit does not cut it. If you'd take a look, the PT_GNU_STACK entry's permissions field specifies what permissions the stack must have, not the presence of the field. So at least two bits are needed which only adds to the problems of finding appropriate bits. -- ➧ Ulrich Drepper ➧ Red Hat, Inc. ➧ 444 Castro St ➧ Mountain View, CA ❖