From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932467Ab2DKAEF (ORCPT ); Tue, 10 Apr 2012 20:04:05 -0400 Received: from lennier.cc.vt.edu ([198.82.162.213]:48014 "EHLO lennier.cc.vt.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759834Ab2DKAED (ORCPT ); Tue, 10 Apr 2012 20:04:03 -0400 X-Mailer: exmh version 2.7.2 01/07/2005 with nmh-1.4-dev To: "H. Peter Anvin" Cc: Cyrill Gorcunov , Andrew Morton , Oleg Nesterov , "Eric W. Biederman" , Pavel Emelyanov , Andrey Vagin , KOSAKI Motohiro , Ingo Molnar , Thomas Gleixner , Glauber Costa , Andi Kleen , Tejun Heo , Matt Helsley , Pekka Enberg , Eric Dumazet , Vasiliy Kulikov , Alexey Dobriyan , Michal Marek , Frederic Weisbecker , linux-kernel@vger.kernel.org, Jonathan Corbet Subject: Re: + syscalls-x86-add-__nr_kcmp-syscall-v8.patch added to -mm tree In-Reply-To: Your message of "Mon, 09 Apr 2012 16:22:38 -0700." <4F836F3E.9090207@zytor.com> From: Valdis.Kletnieks@vt.edu References: <20120215143606.GA14037@redhat.com> <20120215160652.GA17680@redhat.com> <20120215162752.GF4533@moon> <20120409151027.7f3e0fa5.akpm@linux-foundation.org> <20120409222443.GW1625@moon> <4F836F3E.9090207@zytor.com> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="==_Exmh_1334102540_1904P"; micalg=pgp-sha1; protocol="application/pgp-signature" Content-Transfer-Encoding: 7bit Date: Tue, 10 Apr 2012 20:02:21 -0400 Message-ID: <8169.1334102541@turing-police.cc.vt.edu> X-Mirapoint-Received-SPF: 198.82.161.152 auth3.smtp.vt.edu Valdis.Kletnieks@vt.edu 2 pass X-Junkmail-Status: score=10/50, host=steiner.cc.vt.edu X-Junkmail-Signature-Raw: score=unknown, refid=str=0001.0A020204.4F84CA0E.001D,ss=1,re=0.000,fgs=0, ip=0.0.0.0, so=2011-07-25 19:15:43, dmn=2011-05-27 18:58:46, mode=single engine X-Junkmail-IWF: false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --==_Exmh_1334102540_1904P Content-Type: text/plain; charset=us-ascii On Mon, 09 Apr 2012 16:22:38 -0700, "H. Peter Anvin" said: > On 04/09/2012 03:24 PM, Cyrill Gorcunov wrote: > >> > >> Having re-read most of the (enormous) email discussion on the kcmp() > >> syscall patch, I'm thinking: > >> > >> - Nobody seems to understand the obfuscation logic. Jon sounded > >> confused, Oleg sounds confused and it's rather unclear what it does, > >> how it does it and why it does it. > > > > The obfuscation logic was done with great help from hpa@. And the main > > idea was to have ordered results after obfuscation. Per-type noise increase > > randomization of results. So Andrew, I actually dont know what to add > > here. We don't want to provide kernel order back to user-space in > > naked manner. > > > > The obfuscation logic is to provide a 1:1 mapping but which doesn't > preserve ordering, thereby avoid leaking information of kernel pointers > to user space. Oh, OK... Ignore my previous note then. But we should lose the comment that implies we have an ordering? --==_Exmh_1334102540_1904P Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) Comment: Exmh version 2.5 07/13/2001 iQIVAwUBT4TKDAdmEQWDXROgAQLrZw//ekaoXqNZljXABAr8WtgWdZzz8HVQWjKP q1Sy+Bc18DNWORLCGjM/a0+VuGEpaG8nMN4ecOEvIlVOjFEnaubNKaBYCEUL1xth 6KqEpcurzWyVnPNUxGqRajIS5XYfflr+b8D0S/WxQhIgjUQTo33UXHUsfV45xp40 AOuDLz/QA0cbEhLM498p2Gmxx08/EubqZlnefRBiGuJghojnS/1tFtgpjtzAsubY RR3eVMzpwoeDsXQi9FJD9VpWrI75hwq+jCES2SiQCIJPWc1aW3dYHZ3g4NU/A2Ma mI/c5ogLmmElZJNRlnY/ARLnx6/3ArGn5IjPXdwczDI8C2KaGlHK/Av9BKbNliIX 1IcCtkLj6AK3jooV1v6MfHonvaW/VFvlHAhKiZWvHsQgwbu4jcg6uhhckBOGy2tp n6E8H9aAhdOrXUPQZwfN6Ug8ZCJEwsUZ17CApvSrrECWfsVYaslUxCmRPEjdhBPE wZ4cWHKsxnFSeXOYry8hucjZz1Agf23uxQg3/z5Aoh4vd7p665f2OftPxF5P8pvH 5ry7P9dGNCe+wE4CnrcrY61bL/mCFnuZE/SiazjuhdvCV2oD+bD+fQCc60cTjuwq iwzn0u2PJJ/n2SlWQzhUZ7Nfi94BPlNVJEY1+3Jl5XULxj1ZawwPt4yTcjk57bgy qqcPneg49WA= =/4d3 -----END PGP SIGNATURE----- --==_Exmh_1334102540_1904P--