Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751289AbZGSTzZ (ORCPT ); Sun, 19 Jul 2009 15:55:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751079AbZGSTzY (ORCPT ); Sun, 19 Jul 2009 15:55:24 -0400 Received: from one.firstfloor.org ([213.235.205.2]:51277 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750893AbZGSTzX (ORCPT ); Sun, 19 Jul 2009 15:55:23 -0400 To: Linus Torvalds Cc: Athanasius , Julien TINNES , linux-kernel , Greg KH , Tavis Ormandy , Christoph Hellwig , Kees Cook , Eugene Teo Subject: Re: [link@miggy.org: Re: [patch 2/8] personality: fix PER_CLEAR_ON_SETID (CVE-2009-1895)] From: Andi Kleen References: <20090718202512.GA19587@suse.de> <20090718212812.GI6722@miggy.org> <4A6278FD.20807@cr0.org> <20090719122701.GJ6722@miggy.org> Date: Sun, 19 Jul 2009 21:55:19 +0200 In-Reply-To: (Linus Torvalds's message of "Sun, 19 Jul 2009 12:27:05 -0700 (PDT)") Message-ID: <87r5wc4fdk.fsf@basil.nowhere.org> User-Agent: Gnus/5.1008 (Gnus v5.10.8) Emacs/22.3 (gnu/linux) 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: 1455 Lines: 31 Linus Torvalds writes: > > Other binaries are unhappy with address space randomization because they > need to get the absolute maximum contiguous VM space for some big array. > Ok, so that's less of an issue in 64-bit mode, but there really are > programs out there that link everything statically and want to run at a > low virtual address so that they can get 2.5GB of virtual memory for one > single big allocation. I've written crap like that myself. I'm not _proud_ > of it, but I could easily see that programs like that could be unhappy if > the system wiggles mmap's around for security issues. Another common reason for not supporting randomized mappings is when the program loads a "core file" that has pointers to data on each boot, as a faster way to initialize data structures. That's common with LISP like languages for example, but even e.g. gcc's pre compiled headers implementation works like this. > Because compatibility is always of paramount importance. If you want to give it a security angle: not supporting an old application anymore is a very severe DoS attack for people using it. -Andi -- ak@linux.intel.com -- Speaking for myself only. -- 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/