From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760304AbZEFQ7i (ORCPT ); Wed, 6 May 2009 12:59:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753559AbZEFQ71 (ORCPT ); Wed, 6 May 2009 12:59:27 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:58701 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753112AbZEFQ70 (ORCPT ); Wed, 6 May 2009 12:59:26 -0400 Date: Wed, 6 May 2009 09:48:20 -0700 (PDT) From: Linus Torvalds X-X-Sender: torvalds@localhost.localdomain To: Matt Mackall cc: Ingo Molnar , "Eric W. Biederman" , Arjan van de Ven , Jake Edge , security@kernel.org, Linux Kernel Mailing List , James Morris , linux-security-module@vger.kernel.org, Eric Paris , Alan Cox , Roland McGrath , mingo@redhat.com, Andrew Morton , Greg KH , Dave Jones Subject: Re: [Security] [PATCH] proc: avoid information leaks to non-privileged processes In-Reply-To: <20090506162543.GT31071@waste.org> Message-ID: References: <20090504125124.0f469970@infradead.org> <20090505055011.GE31071@waste.org> <20090505063156.GA24504@elte.hu> <20090505195246.GC21973@elte.hu> <20090505202219.GL31071@waste.org> <20090506103034.GA25203@elte.hu> <20090506162543.GT31071@waste.org> User-Agent: Alpine 2.01 (LFD 1184 2008-12-16) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 6 May 2009, Matt Mackall wrote: > On Wed, May 06, 2009 at 12:30:34PM +0200, Ingo Molnar wrote: > > (Also, obviously "only" covering 95% of the Linux systems has its > > use as well. Most other architectures have their own cycle counters > > as well.) > > X86 might be 95% of desktop. But it's a small fraction of Linux > systems once you count cell phones, video players, TVs, cameras, GPS > devices, cars, routers, etc. almost none of which are x86-based. In > fact, just Linux cell phones (with about an 8% share of a 1.2billion > devices per year market) dwarf Linux desktops (maybe 5% of a > 200m/y market). Matt, are you willing to ack my suggested patch which adds history to the mix? Did somebody test that? I have this memory of there being an "exploit" program to show the non-randomness of the values, but I can't recall details, and would really want to get a second opinion from somebody who cares about PRNG's. Linus