Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752466AbWKBVYw (ORCPT ); Thu, 2 Nov 2006 16:24:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752626AbWKBVYv (ORCPT ); Thu, 2 Nov 2006 16:24:51 -0500 Received: from pat.uio.no ([129.240.10.4]:57518 "EHLO pat.uio.no") by vger.kernel.org with ESMTP id S1752455AbWKBVYu (ORCPT ); Thu, 2 Nov 2006 16:24:50 -0500 Subject: Re: Security issues with local filesystem caching From: Trond Myklebust To: David Howells Cc: Stephen Smalley , Karl MacMillan , jmorris@namei.org, chrisw@sous-sol.org, selinux@tycho.nsa.gov, linux-kernel@vger.kernel.org, aviro@redhat.com In-Reply-To: <32754.1162499917@redhat.com> References: <1162496968.6071.38.camel@lade.trondhjem.org> <1162402218.32614.230.camel@moss-spartans.epoch.ncsc.mil> <1162387735.32614.184.camel@moss-spartans.epoch.ncsc.mil> <16969.1161771256@redhat.com> <31035.1162330008@redhat.com> <4417.1162395294@redhat.com> <25037.1162487801@redhat.com> <32754.1162499917@redhat.com> Content-Type: text/plain Date: Thu, 02 Nov 2006 16:24:27 -0500 Message-Id: <1162502667.6071.66.camel@lade.trondhjem.org> Mime-Version: 1.0 X-Mailer: Evolution 2.8.1 Content-Transfer-Encoding: 7bit X-UiO-Spam-info: not spam, SpamAssassin (score=-3.794, required 12, autolearn=disabled, AWL 1.21, UIO_MAIL_IS_INTERNAL -5.00) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1114 Lines: 28 On Thu, 2006-11-02 at 20:38 +0000, David Howells wrote: > Trond Myklebust wrote: > > > Just why are you doing all this? Why do we need a back-end that requires > > all this extra client-side security infrastructure in order to work? > > Well, both Christoph and Al are of the opinion that I should be using > vfs_mkdir() and co rather than bypassing the security and calling inode ops > directly. ...but why are you needing to call vfs_mkdir? I thought the standard cachefs backend just uses a pool of files, rather like the original AFS cache did. Are you trying to mirror the layout and the permissions of the NFS filesystem? That is a lot more work than it is worth... > Also I should be setting security labels on the files I create. To what end? These files shouldn't need to be made visible to userland at all. Cheers, Trond - 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/