Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265682AbUA0WUd (ORCPT ); Tue, 27 Jan 2004 17:20:33 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265711AbUA0WUd (ORCPT ); Tue, 27 Jan 2004 17:20:33 -0500 Received: from 104.engsoc.carleton.ca ([134.117.69.104]:46500 "EHLO quickman.certainkey.com") by vger.kernel.org with ESMTP id S265682AbUA0WUX (ORCPT ); Tue, 27 Jan 2004 17:20:23 -0500 Date: Tue, 27 Jan 2004 17:16:58 -0500 From: Jean-Luc Cooke To: linux-kernel@vger.kernel.org Subject: Re: Encrypted Filesystem Message-ID: <20040127221658.GB16413@certainkey.com> References: <20040127220153.GA4992@delft.aura.cs.cmu.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040127220153.GA4992@delft.aura.cs.cmu.edu> User-Agent: Mutt/1.5.5.1+cvs20040105i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2884 Lines: 71 Ah, can someone explain why encrypted loopback doesn't solve this? JLC On Tue, Jan 27, 2004 at 05:01:54PM -0500, Jan Harkes wrote: > On Tue, Jan 27, 2004 at 12:43:21AM +0000, Adam Sampson wrote: > > Michael A Halcrow writes: > > > > > - Userland filesystem-based (EncFS+FUSE, CryptoFS+LUFS) > > > > Going off on a tangent... > > > > There are all sorts of potentially-interesting things that could be > > done if Linux had a userspace filesystem mechanism included in the > > standard kernel -- as well as encryption, there's also network > > filesystems, various sorts of specialised caching (such as Zero > > Install), automounter-like systems, prototyping and so on. > > > > Is there a technical reason that none of the userspace filesystem > > layers have been included in the stock kernel, or is it just that > > nobody's submitted any of them for inclusion yet? > > Ehh, Coda's kernel module does just that. It is used by the userspace > cache manager of the Coda Distributed File System. > > http://www.coda.cs.cmu.edu/ > > But several other projects seem to be using it, > > http://uservfs.sourceforge.net/ > http://dav.sourceforge.net/ > > The interface to userspace a bit clumsy to work with, but there are > kernel modules for FreeBSD/NetBSD/Solaris and an experimental one for > Windows 2000/NT/XP, which makes any significant changes a bit of a pain. > > It does have it's pecularities, reads and writes are not passed up to > userspace, only the open and close VFS calls. This makes the module > reasonably quite simple as it doesn't have to deal with VM issues and it > isn't susceptible to deadlocks, > > app wants to read data from a file -> > userspace application requires memory allocation to provide this data -> > VM tries to write out dirty data associated with the Coda mountpoint == > deadlock > > So whole file caching keeps the kernel module more portable and > simplifies the userspace code. But it makes things like streaming > reads/writes or quotas impossible. If you want to provide encryption > there you would have to store an unencrypted copy of every open file > somewhere on disk or in ramfs/tmpfs and incur the cost of (de)crypting > (and (de)compressing) whenever it is opened or closed. > > Jan > > - > 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/ -- http://www.certainkey.com Suite 4560 CTTC 1125 Colonel By Dr. Ottawa ON, K1S 5B6 - 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/