From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933112Ab2C1VYT (ORCPT ); Wed, 28 Mar 2012 17:24:19 -0400 Received: from www.linutronix.de ([62.245.132.108]:46773 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932894Ab2C1VYP (ORCPT ); Wed, 28 Mar 2012 17:24:15 -0400 Date: Wed, 28 Mar 2012 23:24:07 +0200 (CEST) From: Thomas Gleixner To: Kees Cook cc: Ingo Molnar , Serge Hallyn , LKML , Darren Hart , Peter Zijlstra , Andrew Morton , Jiri Kosina , "Eric W. Biederman" , David Howells , kernel-hardening@lists.openwall.com, spender@grsecurity.net Subject: Re: [PATCH] futex: do not leak robust list to unprivileged process In-Reply-To: Message-ID: References: <20120319231253.GA20893@www.outflux.net> <20120320133141.GC2918@peqn> <20120320172300.GA8888@gmail.com> User-Agent: Alpine 2.02 (LFD 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 28 Mar 2012, Kees Cook wrote: > On Thu, Mar 22, 2012 at 4:46 PM, Thomas Gleixner wrote: > > On Tue, 20 Mar 2012, Ingo Molnar wrote: > >> * Kees Cook wrote: > >> > On Tue, Mar 20, 2012 at 10:02 AM, Thomas Gleixner wrote: > >> > > I really wonder why we have this syscall at all. > >> > > >> > The documentation I found yesterday while looking at this was: > >> > http://linux.die.net/man/2/get_robust_list > >> > > >> > Which says "The system call is only available for debugging > >> > purposes and is not needed for normal operations. Both system > >> > calls are not available to application programs as functions; > >> > they can be called using the syscall(3) function." > >> > > >> > Dropping the syscall entirely would certainly make it secure. > >> > ;) > >> > >> The thinking was API completeness. In general it's possible for > >> a sufficiently privileged task to figure out all the state of a > >> task. We can query timers, fds - the robust list is such a > >> resource as well. The information leakage was obviously not > >> intended. > > > > So I think it's safe to take Kees' patch as is. On top of that we > > should add a WARN_ONCE when the syscall is invoked and schedule the > > sucker for removal. > > Can someone claim the first patch? It looks like not everyone agrees > about removal, but I'd like to see at least the first one get in. :) It's on my list for tomorrow.