From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2992721AbXCBXLK (ORCPT ); Fri, 2 Mar 2007 18:11:10 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S2992720AbXCBXLJ (ORCPT ); Fri, 2 Mar 2007 18:11:09 -0500 Received: from mail.screens.ru ([213.234.233.54]:56884 "EHLO mail.screens.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2992724AbXCBXLI (ORCPT ); Fri, 2 Mar 2007 18:11:08 -0500 Date: Sat, 3 Mar 2007 02:11:03 +0300 From: Oleg Nesterov To: Chuck Ebbert Cc: John Reiser , Andi Kleen , Ingo Molnar , Arjan van de Ven , Paul Mundt , Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: + fully-honor-vdso_enabled.patch added to -mm tree Message-ID: <20070302231103.GA249@tv-sign.ru> References: <20070301175207.GA849@tv-sign.ru> <45E891E6.7090807@BitWagon.com> <45E8A300.9020001@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <45E8A300.9020001@redhat.com> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On 03/02, Chuck Ebbert wrote: > > John Reiser wrote: > > The value of ->sysenter_return is interpreted in user space by the > > sysexit instruction; nobody else cares what the value is. The kernel > > is not required to provide a good value when vdso_enabled is zero, > > because the kernel has not told the process that sysenter is valid > > (by setting AT_SYSINFO.) > > Doesn't matter because a malicious user can still execute sysenter. > We do have to deal with that somehow, so we have to put something > safe in there. Yes, but a malicious user can't make any harm to the system, sysexit jumps to ->sysenter_return when user_mode() is true, right? (I am asking because I don't know in details what sysexit does). Oleg.