From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 23 Aug 2001 12:52:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 23 Aug 2001 12:52:07 -0400 Received: from ffke-campus-gw.mipt.ru ([194.85.82.65]:40322 "EHLO www.2ka.mipt.ru") by vger.kernel.org with ESMTP id ; Thu, 23 Aug 2001 12:52:02 -0400 Message-Id: <200108231653.f7NGrOl32250@www.2ka.mipt.ru> Date: Thu, 23 Aug 2001 20:56:02 +0400 From: Evgeny Polyakov To: Alan Cox Cc: linux-kernel@vger.kernel.org, torvalds@transmeta.com Subject: Re: [PATCH] this patch add a possibility to add a random offset to the stack on exec. In-Reply-To: In-Reply-To: <200108230130.f7N1Uol14698@www.2ka.mipt.ru> Reply-To: johnpol@2ka.mipt.ru X-Mailer: stuphead ver. 0.5.3 (Wiskas) (GTK+ 1.2.7; Linux 2.4.9; i686) Organization: MIPT Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hello. On Thu, 23 Aug 2001 13:47:31 +0100 (BST) Alan Cox wrote: >> "Add a possibility to add a random offset to the stack on exec. This makes >> it slightly harder to write generic buffer overflows. This doesn't really >> give any real security, but it raises the bar for script-kiddies and it's >> really cheap." AC> Its so slight its useless, and the randomness makes it hard to verify AC> you AC> fixed a problem. Remember once an exploit appears a box will get scanned AC> hundreds of times - someone will get the right offset 8) You want to tell, that running 2 process one directky after another( like exploits do), and esp will be the same, even with random addition? It's impossible. But i quite understand your position in this question :(. AC> There is another good reason for offseting stacks within the page - AC> especially the kernel stacks which is to avoid things like each apache AC> task sleeping with wait queues on the same cache colour --- WBR. //s0mbre