From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265346AbUBFJdj (ORCPT ); Fri, 6 Feb 2004 04:33:39 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265359AbUBFJdi (ORCPT ); Fri, 6 Feb 2004 04:33:38 -0500 Received: from cpe-24-221-190-179.ca.sprintbbd.net ([24.221.190.179]:5274 "EHLO myware.akkadia.org") by vger.kernel.org with ESMTP id S265346AbUBFJdC (ORCPT ); Fri, 6 Feb 2004 04:33:02 -0500 Message-ID: <40235E24.2060500@redhat.com> Date: Fri, 06 Feb 2004 01:28:04 -0800 From: Ulrich Drepper Organization: Red Hat, Inc. User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7a) Gecko/20040205 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Andrea Arcangeli CC: john stultz , lkml , Jamie Lokier , Chris McDermott , Wim Coekaerts , Joel Becker , "Martin J. Bligh" Subject: Re: [RFC][PATCH] linux-2.6.2_vsyscall-gtod_B2.patch References: <1076037045.757.21.camel@cog.beaverton.ibm.com> <20040206040123.GN31926@dualathlon.random> In-Reply-To: <20040206040123.GN31926@dualathlon.random> X-Enigmail-Version: 0.83.2.0 X-Enigmail-Supports: pgp-inline, pgp-mime Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andrea Arcangeli wrote: > with regards to Ulrich's security related comments, this won't make any > difference compared to the fixed address version either, since the > vsyscall page is still at a fixed address in the fixmap area, Gee, you don't want to understand it. Even if the official kernel's handling of the vdso puts it at the same address all the time this does not mean this can be engraved in stone. It must be possible to move the page. And I expect this will be the case in our kernels. It is completely unacceptable to use fixed addresses or require the libc to be recompiled for a new address. At the highest security level the vdso address should vary from program run to program run which means there is no way to change the libc. -- ➧ Ulrich Drepper ➧ Red Hat, Inc. ➧ 444 Castro St ➧ Mountain View, CA ❖