Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261230AbVA0Vi4 (ORCPT ); Thu, 27 Jan 2005 16:38:56 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261228AbVA0Vi4 (ORCPT ); Thu, 27 Jan 2005 16:38:56 -0500 Received: from rwcrmhc13.comcast.net ([204.127.198.39]:52726 "EHLO rwcrmhc13.comcast.net") by vger.kernel.org with ESMTP id S261231AbVA0Vil (ORCPT ); Thu, 27 Jan 2005 16:38:41 -0500 Message-ID: <41F95F79.6080904@comcast.net> Date: Thu, 27 Jan 2005 16:39:05 -0500 From: John Richard Moser User-Agent: Mozilla Thunderbird 1.0 (X11/20041211) X-Accept-Language: en-us, en MIME-Version: 1.0 CC: Arjan van de Ven , linux-kernel@vger.kernel.org, akpm@osdl.org Subject: Re: Patch 4/6 randomize the stack pointer References: <20050127101117.GA9760@infradead.org> <20050127101322.GE9760@infradead.org> <41F92721.1030903@comcast.net> <1106848051.5624.110.camel@laptopd505.fenrus.org> <41F92D2B.4090302@comcast.net> In-Reply-To: X-Enigmail-Version: 0.89.5.0 X-Enigmail-Supports: pgp-inline, pgp-mime Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit To: unlisted-recipients:; (no To-header on input) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1497 Lines: 55 -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Linus Torvalds wrote: > [...] > > Your suggestion of 256MB of randomization for the stack SIMPLY IS NOT > ACCEPTABLE for a lot of uses. People on 32-bit archtiectures have issues > with usable virtual memory areas etc. > I feel the need to point something out here. [TEXT][BRK][MMAP---------------][STACK] Here's a normal layout. [TEXT][BRK][MMAP-------][STACK][MMAP--] Is this one any worse? Just bias non-executable mappings above the stack when, say, half of VMA is used up. Prevent executable mappings from being created up there because PaX' PAGEEXEC and Exec Shield's emulation will be affected by a high-mapping (PaX falls back to kernel-assisted MMU walking, which can be very high overhead; ES just makes everything below the area executable). So, you can do it without losing VMA, in theory. [...] > - -- All content of all messages exchanged herein are left in the Public Domain, unless otherwise explicitly stated. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.0 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org iD8DBQFB+V94hDd4aOud5P8RAqv1AJ9iazEKh//yeaTdraUou9KLQCUG0wCfVbo2 kXYvkauZ8+wC7J3nN5IzoTY= =tvyp -----END PGP SIGNATURE----- - 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/