From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760718AbZE3NWe (ORCPT ); Sat, 30 May 2009 09:22:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756594AbZE3NW1 (ORCPT ); Sat, 30 May 2009 09:22:27 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:32951 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757756AbZE3NW0 (ORCPT ); Sat, 30 May 2009 09:22:26 -0400 Subject: Re: [patch 0/5] Support for sanitization flag in low-level page allocator From: Peter Zijlstra To: pageexec@freemail.hu Cc: "Larry H." , Arjan van de Ven , Alan Cox , Ingo Molnar , Rik van Riel , linux-kernel@vger.kernel.org, Linus Torvalds , linux-mm@kvack.org, Ingo Molnar In-Reply-To: <4A211BA8.8585.17B52182@pageexec.freemail.hu> References: <20090522073436.GA3612@elte.hu> , <20090530054856.GG29711@oblivion.subreption.com> , <1243679973.6645.131.camel@laptop> <4A211BA8.8585.17B52182@pageexec.freemail.hu> Content-Type: text/plain Date: Sat, 30 May 2009 15:21:47 +0200 Message-Id: <1243689707.6645.134.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.26.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2009-05-30 at 13:42 +0200, pageexec@freemail.hu wrote: > > Why waste time on this? > > e.g., when userland executes a syscall, it 'can run kernel code'. if that kernel > code (note: already exists, isn't provided by the attacker) gives unintended > kernel memory back to userland, there is a problem. that problem is addressed > in part by early sanitizing of freed data. Right, so the whole point is to minimize the impact of actual bugs, right? So why not focus on fixing those actual bugs? Can we create tools to help us find such bugs faster? We use sparse for a lot of static checking, we create things like lockdep and kmemcheck to dynamically find trouble. Can we instead of working around a problem, fix the actual problem? From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with ESMTP id CF1B86B00C5 for ; Sat, 30 May 2009 09:21:47 -0400 (EDT) Subject: Re: [patch 0/5] Support for sanitization flag in low-level page allocator From: Peter Zijlstra In-Reply-To: <4A211BA8.8585.17B52182@pageexec.freemail.hu> References: <20090522073436.GA3612@elte.hu> , <20090530054856.GG29711@oblivion.subreption.com> , <1243679973.6645.131.camel@laptop> <4A211BA8.8585.17B52182@pageexec.freemail.hu> Content-Type: text/plain Date: Sat, 30 May 2009 15:21:47 +0200 Message-Id: <1243689707.6645.134.camel@laptop> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: pageexec@freemail.hu Cc: "Larry H." , Arjan van de Ven , Alan Cox , Ingo Molnar , Rik van Riel , linux-kernel@vger.kernel.org, Linus Torvalds , linux-mm@kvack.org, Ingo Molnar List-ID: On Sat, 2009-05-30 at 13:42 +0200, pageexec@freemail.hu wrote: > > Why waste time on this? > > e.g., when userland executes a syscall, it 'can run kernel code'. if that kernel > code (note: already exists, isn't provided by the attacker) gives unintended > kernel memory back to userland, there is a problem. that problem is addressed > in part by early sanitizing of freed data. Right, so the whole point is to minimize the impact of actual bugs, right? So why not focus on fixing those actual bugs? Can we create tools to help us find such bugs faster? We use sparse for a lot of static checking, we create things like lockdep and kmemcheck to dynamically find trouble. Can we instead of working around a problem, fix the actual problem? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org