Return-Path: Received: from nm24-vm0.access.bullet.mail.mud.yahoo.com ([66.94.236.143]:22699 "HELO nm24-vm0.access.bullet.mail.mud.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1755375Ab1ILWib (ORCPT ); Mon, 12 Sep 2011 18:38:31 -0400 Message-ID: <4E6E89E0.4010406@schaufler-ca.com> Date: Mon, 12 Sep 2011 15:38:24 -0700 From: Casey Schaufler To: "J. Bruce Fields" CC: Valdis.Kletnieks@vt.edu, "Aneesh Kumar K.V" , agruen@kernel.org, akpm@linux-foundation.org, dhowells@redhat.com, linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, LSM , Casey Schaufler Subject: Re: [PATCH -V6 00/26] New ACL format for better NFSv4 acl interoperability References: <1315243548-18664-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <4E655049.6060507@schaufler-ca.com> <108028.1315442771@turing-police.cc.vt.edu> <4E6E7ACC.8040003@schaufler-ca.com> <20110912222014.GA17483@fieldses.org> In-Reply-To: <20110912222014.GA17483@fieldses.org> Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 On 9/12/2011 3:20 PM, J. Bruce Fields wrote: > On Mon, Sep 12, 2011 at 02:34:04PM -0700, Casey Schaufler wrote: >> On 9/7/2011 5:46 PM, Valdis.Kletnieks@vt.edu wrote: >>> On Mon, 05 Sep 2011 15:42:17 PDT, Casey Schaufler said: >>>> On 9/5/2011 10:25 AM, Aneesh Kumar K.V wrote: >>>>> The following set of patches implements VFS and ext4 changes needed to implement >>>>> a new acl model for linux. Rich ACLs are an implementation of NFSv4 ACLs, >>>>> extended by file( masks to fit into the standard POSIX file permission model. >>>>> They are designed to work seamlessly locally as well as across the NFSv4 and >>>>> CIFS/SMB2 network file system protocols. >>>> POSIX ACLs predate the LSM and can't be done as an LSM due to >>>> the interactions between mode bits and ACLs as defined by the >>>> POSIX DRAFT specification. > I don't know LSM so don't understand what you mean when you say that > interactions between mode bits and ACLs would make an ACL model hard to > implement as an LSM. POSIX ACLs require that the file permission bits change when the ACL changes. This interaction violates the strict "additional restriction" model of the LSM. > But in any case the rich acl/mode bit interactions are similar to the > posix acl/mode bit interactions, so the same issue probably applies. It would help if you knew for sure and could explain the interaction in sufficient detail to justify the position. > > --b. >