Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751801AbXIRXmV (ORCPT ); Tue, 18 Sep 2007 19:42:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750890AbXIRXmO (ORCPT ); Tue, 18 Sep 2007 19:42:14 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:49192 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750834AbXIRXmN (ORCPT ); Tue, 18 Sep 2007 19:42:13 -0400 Date: Wed, 19 Sep 2007 05:14:59 +0530 (IST) From: Satyam Sharma X-X-Sender: satyam@enigma.security.iitk.ac.in To: Kyle Moffett cc: Trond Myklebust , "J. Bruce Fields" , Jan Engelhardt , Linux Kernel Mailing List Subject: Re: NFS4 authentification / fsuid In-Reply-To: <5B1FC03A-6819-4C6C-91D3-F3022B798EF4@mac.com> Message-ID: References: <1188484155.6755.38.camel@heimdal.trondhjem.org> <1188484337.6755.41.camel@heimdal.trondhjem.org> <1188486240.6755.51.camel@heimdal.trondhjem.org> <20070830214431.GF10808@fieldses.org> <20070906150616.GA28565@fieldses.org> <0D66E86D-8D97-45D7-9C2A-7AB5F42845B5@mac.com> <1189121714.6672.38.camel@heimdal.trondhjem.org> <5B1FC03A-6819-4C6C-91D3-F3022B798EF4@mac.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2582 Lines: 58 On Thu, 6 Sep 2007, Kyle Moffett wrote: > > On Sep 06, 2007, at 19:35:14, Trond Myklebust wrote: > > > > On Thu, 2007-09-06 at 19:30 -0400, Kyle Moffett wrote: > > > > > > On Sep 06, 2007, at 11:06:16, J. Bruce Fields wrote: > > > > The question of how to protect against someone with *physical* ^^^^^^^^^^^^^^^^^^^^^^^ > > > > access certainly is more difficult, but surely that's a separate ^^^^^^ > > > > problem. > > > > > > Actually, that's a fairly simple problem (barring disassembling the system ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > > and attaching a hardware debugger). You encrypt the root filesystem and > > > require a password to boot (See: LUKS). Debian has built-in support for > > > installing onto fs-on-LVM-on-crypt-on-RAID, and it works quite well on all > > > the laptops I use regularly. It's not even much of a speed penalty; once > > > you take the overhead of hitting a 5400RPM laptop drive you can chew > > > thousands of cycles of CPU without anybody noticing (much). Then all you > > > have to do is burn a copy of your /boot with bootloader onto some > > > read-only media (like a finalized CDROM/DVDROM) and you're set to go. > > > > Disconnect battery, and watch boot password go 'poof!'. > > Umm, I did say "encrypt the root filesystem", didn't I? Booting my laptops ^^^^^^^ The whole *point* here is to secure against physical access -- then how can you assume "barring disassembling the system"? If you're not considering attacks such as those, then how _are_ you solving the physical access problem in the first place? :-) > this way follows this procedure: > 1) Enter BIOS boot menu > 2) Insert /boot CDROM > 3) Select the "CDROM" entry > 4) Wait for kernel to start and run through initramfs > 5) Type password into the initramfs prompt so that it can DECRYPT THE ROOT > FILESYSTEM > 6) Continue to boot the system. > > Under this setup, tinkering with my BIOS does virtually nothing; the only > avenues of attack are strictly of the "Install a hardware keylogger" variety. Doesn't flashing/replacing your BIOS firmware/chip count as tinkering? Then I don't really need a "hardware keylogger", do I ... - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/