Date: Wed, 13 Jul 2011 13:35:34 -0400
To: Benjamin Coddington <bcodding@uvm.edu>
Cc: linux-nfs@vger.kernel.org
Subject: Re: multiple service identities for svcgssd
Message-ID: <20110713173534.GA11665@fieldses.org>
References: <3EA8A380-460C-4CDC-9591-7034D2E38D93@uvm.edu>
Content-Type: text/plain; charset=us-ascii
In-Reply-To: <3EA8A380-460C-4CDC-9591-7034D2E38D93@uvm.edu>
From: "J. Bruce Fields" <bfields@fieldses.org>
Sender: linux-nfs-owner@vger.kernel.org
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On Wed, Jul 13, 2011 at 12:03:03PM -0400, Benjamin Coddington wrote:
> I am working on a linux NFS cluster that requires a single svcgssd to establish contexts under multiple service names.
> 
> In this scenario, svcgssd can be called with "-n" so that it acquires creds at context creation.  After running this way I found svcgssd opens a file to the kerberos replay cache for every context/cred, eventually reaching ulimit.  For a busy cluster with many different client-user pairs that becomes a problem.  I am lost in the gss_krb5 code, but suspect that the kerberos code leaks credentials in this configuration.
> 
> Ondrej Palkovsky submitted a patch to specify multiple identities and acquire creds up-front using multiples of "-h": http://marc.info/?l=linux-nfsv4&m=123685185324902&w=2
> 
> I've updated that work to be current to nfs-utils-1.2.3 which solves our immediate problem, and it works well -- but running svcgssd with '-n' is still going to leak file handles to the replay cache.  What's the best way to fix this?  Can the created-on-the-fly cred can be re-used for subsequent contexts?

Sounds like a likely kerberos bug as well--may be use asking the
kerberos folks?

--b.