netdev - Re: [Regression] "SUNRPC: Add "@len" parameter to gss_unwrap()" breaks NFS Kerberos on upstream stable 5.4.y

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Date:   Fri, 17 Jul 2020 19:29:44 +0200
From:   Pierre Sauter <pierre.sauter@...m.de>
To:     Chuck Lever <chuck.lever@...cle.com>
Cc:     Kai-Heng Feng <kai.heng.feng@...onical.com>,
        matthew.ruffell@...onical.com,
        linux-stable <stable@...r.kernel.org>,
        Linux NFS Mailing List <linux-nfs@...r.kernel.org>,
        "open list:NETWORKING DRIVERS" <netdev@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>,
        linux-kernel-owner@...r.kernel.org
Subject: Re: [Regression] "SUNRPC: Add "@len" parameter to gss_unwrap()" breaks NFS Kerberos on upstream stable 5.4.y

Hi Chuck,

Am Donnerstag, 16. Juli 2020, 21:25:40 CEST schrieb Chuck Lever:
> So this makes me think there's a possibility you are not using upstream
> stable kernels. I can't help if I don't know what source code and commit
> stream you are using. It also makes me question the bisect result.

Yes you are right, I was referring to Ubuntu kernels 5.4.0-XX. From the
discussion in the Ubuntu bugtracker I got the impression that Ubuntu kernels
5.4.0-XX and upstream 5.4.XX are closely related, obviously they are not. The
bisection was done by the original bug reporter and also refers to the Ubuntu
kernel.

In the meantime I tested v5.4.51 upstream, which shows no problems. Sorry for
the bother.

> > My krb5 etype is aes256-cts-hmac-sha1-96.
> 
> Thanks! And what is your NFS server and filesystem? It's possible that the
> client is not estimating the size of the reply correctly. Variables include
> the size of file handles, MIC verifiers, and wrap tokens.

The server is Debian with v4.19.130 upstream, filesystem ext4.

> You might try:
> 
> e8d70b321ecc ("SUNRPC: Fix another issue with MIC buffer space")

That one is actually in Ubuntus 5.4.0-40, from looking at the code.

Best Regards
-- 
Pierre Sauter
Studentenwerk München
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