Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758819AbYBGKdq (ORCPT ); Thu, 7 Feb 2008 05:33:46 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755206AbYBGKdi (ORCPT ); Thu, 7 Feb 2008 05:33:38 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:40972 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755038AbYBGKdh (ORCPT ); Thu, 7 Feb 2008 05:33:37 -0500 Date: Thu, 7 Feb 2008 11:32:32 +0100 From: Ingo Molnar To: Geert Uytterhoeven Cc: Jiri Kosina , Andrew Morton , Arjan van de Ven , Randy Dunlap , Hugh Dickins , Pavel Machek , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] ASLR: add possibility for more fine-grained tweaking Message-ID: <20080207103231.GD16735@elte.hu> References: <20080206134959.GA25689@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1648 Lines: 41 * Geert Uytterhoeven wrote: > On Wed, 6 Feb 2008, Ingo Molnar wrote: > > @@ -541,6 +541,18 @@ config ELF_CORE > > help > > Enable support for generating core dumps. Disabling saves about 4k. > > > > +config COMPAT_BRK > > + bool "Disable heap randomization" > > + default y > > + help > > + Randomizing heap placement makes heap exploits harder, but it > > + also breaks ancient binaries (including anything libc5 based). > > + This option changes the bootup default to heap randomization > > + disabled, and can be overriden runtime by setting > > + /proc/sys/kernel/randomize_va_space to 2. > > + > > + On non-ancient distros (post-2000 ones) Y is usually a safe choice. > > Somehow my belly feeling tells me something is wrong with this description... > > Ah, a negative option (Y -> disable). So Y is always safe. > > `non-ancient distros' really means `recent distros', and if you have > one, then _N_ should be a safe choice, too? yeah, you are right :-) I'll fix this. btw., "non-ancient distros" does not just mean "recent distros", it really means "just about any distro you picked up in the past 10 years". You'd have to go out on a limb to find something historic (or keep copying /lib/libc5 binaries to new distros like Pavel did) to still have this particular libc5 assumption/breakage. [ Or at least so i hope =B-)] Ingo -- 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/