From owner-freebsd-fs Mon Aug 20 7:39:44 2001 Delivered-To: freebsd-fs@freebsd.org Received: from topperwein.dyndns.org (acs-24-154-28-172.zoominternet.net [24.154.28.172]) by hub.freebsd.org (Postfix) with ESMTP id 036DD37B401; Mon, 20 Aug 2001 07:39:37 -0700 (PDT) (envelope-from behanna@zbzoom.net) Received: from topperwein.dyndns.org (topperwein.dyndns.org [192.168.168.10]) by topperwein.dyndns.org (8.11.4/8.11.4) with ESMTP id f7KEdpv09679; Mon, 20 Aug 2001 10:39:51 -0400 (EDT) (envelope-from behanna@zbzoom.net) Date: Mon, 20 Aug 2001 10:39:46 -0400 (EDT) From: Chris BeHanna Reply-To: Chris BeHanna To: Cc: Subject: Re: DENY ACL's In-Reply-To: <000f01c12982$321d68c0$0200a8c0@kjc2.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-fs@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org On Mon, 20 Aug 2001, Ken Cross wrote: > > > The particular case you show would work, but others won't. > > > > I think that the example given below is the result of badly formed > > security policy. > > Not really. There are real cases in large organizations where that > configuration is perfectly legitimate. OTOH, it is often the result of > "quick-fix" solutions. But that's the real world... > > > > > > For example, suppose the user is a member of GroupA which is allowed > access > > > and also a member of GroupB which is denied access, e.g. "setfacl -m > > > g:GroupA:rwx,g:GroupB: file". (There's no user-specific ACL.) > > > All "deny" ACL's must be checked first, so the user should be denied. > Under > > > the current scheme, I think the "best match" would allow access. > > > > Yes, user will have access to file, but why shouldn't he have it? > > For whatever reason, the administrators decided to explicitly deny access to > GroupB. By definition, that *must* be honored first. I don't make the > rules, but I gotta live by them. ;-) Perhaps I misremember, but weren't there access control systems that use "first match" syntax? That would (partly) solve this problem: GroupB: GroupA:rwx Here, GroupB would match first, and the user would be denied; however, another rule can be added: UserA:rwx GroupB: GroupA:rwx and all is well with the world. -- Chris BeHanna Software Engineer (Remove "bogus" before responding.) behanna@bogus.zbzoom.net I was raised by a pack of wild corn dogs. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message