Subject: Re: NFSv4 behaviour on unknown users
From: Trond Myklebust <Trond.Myklebust@netapp.com>
To: Thomas Haynes <thomas@netapp.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>, Spelic <spelic@shiftmail.org>,
        linux-nfs@vger.kernel.org
In-Reply-To: <99BBEF51-7EB1-4BAA-9B12-F0F98A629C74@netapp.com>
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	 <20101130222651.GB5054@fieldses.org>
	 <1291156414.4393.2.camel@heimdal.trondhjem.org>
	 <20101130223627.GC5054@fieldses.org>
	 <20101201135740.0d3b5948@notabene.brown>
	 <1291173002.7694.7.camel@heimdal.trondhjem.org>
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Date: Thu, 02 Dec 2010 18:18:05 -0500
Message-ID: <1291331885.2915.1.camel@heimdal.trondhjem.org>
Sender: linux-nfs-owner@vger.kernel.org
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On Thu, 2010-12-02 at 17:10 -0600, Thomas Haynes wrote:
> On Dec 1, 2010, at 10:29 AM, J. Bruce Fields wrote:
> 
> > On Tue, Nov 30, 2010 at 10:10:02PM -0500, Trond Myklebust wrote:
> >> 
> >> I think you need to take beepy's words in context here: as I believe I
> >> mentioned previously, RFC3530 (and its predecessor RFC3010) assumed
> >> everyone would be using principals for authenticating, either through
> >> RPCSEC_GSS w/ krb5, or through the SPKM/Lipkey mechanism. So sure was
> >> everyone of this, that AUTH_SYS isn't even mentioned as a valid
> >> authentication mechanism, and so nobody had to worry about the
> >> consequences of using it.
> > 
> > I also wonder whether the value of a transparent upgrade from NFSv3 got
> > a little lost.
> > 
> > To me that seems like the first requirement for version n+1 of
> > anything--that we should be able to upgrade people to version n without
> > their noticing.
> > 
> > Maybe there are features that are necessarily incompatible, and that
> > merit the downside, but the downside--losing the chance to get new
> > features to every user automatically--seems significant to me.
> > 
> > 
> > And, perhaps it's a disease, but I have gotten into the habit of
> > thinking of the (krb5 principal)->(id, gid's) mapping as independent of
> > the (NFSv4 user name)<->(uid) and (NFSv4 group name)<->(gid) mappings.
> > 
> > Granted they have to be coordinated on any reasonably complicated setup.
> > But there are simple cases where they don't necessarily need to be.
> > 
> > E.g. on a dumb "cp -ax / /nfs" backup it doesn't really matter "who"
> > does the backup as long as they have sufficient permissions, since the
> > files will all be explicitly chown'd as they're created.  And with krb5
> > it's simple enough to make that work with a single static mapping from a
> > client-side principal to root on the server.
> > 
> > And, again, that's something that works now with NFSv3.
> > 
> > --b.
> > --
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> 
> 
> Another question is whether or not such an approach would be appreciated
> as part of 3530bis?

You want to add a discussion about AUTH_SYS support for 3530bis? I'd be
OK with that...

-- 
Trond Myklebust
Linux NFS client maintainer

NetApp
Trond.Myklebust@netapp.com
www.netapp.com