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From: Simo Sorce <simo@redhat.com>
To: Cedric Blancher <cedric.blancher@gmail.com>
Cc: Steve Dickson <steved@redhat.com>, Jurjen Bokma <j.bokma@rug.nl>,
	Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
	kerberos <kerberos@mit.edu>
Subject: Re: How to use NFS with multiple principals in different realms?
Date: Wed, 17 Sep 2014 17:31:04 -0400	[thread overview]
Message-ID: <20140917173104.4ea31d95@willson.usersys.redhat.com> (raw)
In-Reply-To: <CALXu0UcQ9YGTLnrjs5+AmVstAWmZ1QcNqOVeYyE-b_ktbfqvjw@mail.gmail.com>

On Wed, 17 Sep 2014 22:30:29 +0200
Cedric Blancher <cedric.blancher@gmail.com> wrote:

> On 17 September 2014 17:05, Simo Sorce <simo@redhat.com> wrote:
> > On Wed, 17 Sep 2014 13:20:19 +0200
> > Cedric Blancher <cedric.blancher@gmail.com> wrote:
> >
> >> What happens if there is no relation between KRB Realm names and
> >> FQDN/DNS? Can the NFS client find out which KRB Realm is used by
> >> the server?
> >
> > Depending on the environment you may have 1 or 2 ways.
> >
> > 1. add domain to realm mapping in the appropriate section in
> > krb5.conf on the client.
> > 2. allow the KDC to send back a referral (but not all clients will
> > ask their own KDC, some can do only 1).
> 
> But how can 1. help? Sure I can have my own krb5.conf but AFAIK
> rpc.gssd only looks at he system /etc/krb5.conf and not at any custom
> user defined location. Basically mount(8) would have to pass the
> location of the custom krb5.conf file to rpc.gssd to facilitate the
> mount, right?

A mount operation is a system-wide operation and requires privileges,
the system krb5.conf is what is used. Trusting a user provided
krb5.conf file for system level operations is not possible.

> I *think* we have a bigger problem here: Kerberos5 support in NFS
> appears to be designed around the philosophy of one realm per machine
> (one-to-rule-them'-all) and not that a single user or machine has
> mounts from many different realms, right?

wrong, the machine just need to 'know' about multiple realms and that
is done via domain_realm mappings, of course you can only have one
realm per dns domain.

Simo.

-- 
Simo Sorce * Red Hat, Inc * New York

      reply	other threads:[~2014-09-17 21:31 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-04  9:04 How to use NFS with multiple principals in different realms? Cedric Blancher
2014-09-04  9:33 ` Jurjen Bokma
2014-09-04 11:25   ` Cedric Blancher
2014-09-04 12:32     ` Jurjen Bokma
2014-09-04 18:35       ` Simo Sorce
2014-09-10  0:31         ` Cedric Blancher
2014-09-10  2:18           ` Nordgren, Bryce L -FS
2014-09-10  6:47             ` Trond Myklebust
2014-09-10 13:06           ` Simo Sorce
2014-09-17 11:20             ` Cedric Blancher
2014-09-17 15:05               ` Simo Sorce
2014-09-17 20:30                 ` Cedric Blancher
2014-09-17 21:31                   ` Simo Sorce [this message]

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