Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Tue, 27 Mar 2018 23:06:14 +0100 (BST)
From:   Michael Young <m.a.young@durham.ac.uk>
To:     Eric Biggers <ebiggers@google.com>,
        Herbert Xu <herbert@gondor.apana.org.au>
cc:     "J. Bruce Fields" <bfields@fieldses.org>,
        Jeff Layton <jlayton@kernel.org>,
        Trond Myklebust <trond.myklebust@primarydata.com>,
        Anna Schumaker <anna.schumaker@netapp.com>,
        linux-nfs@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: NFS mounts failing when keytab present on client
Message-ID: <alpine.LFD.2.21.1803272126070.3013@austen3.home>
User-Agent: Alpine 2.21 (LFD 202 2017-01-01)
MIME-Version: 1.0
Content-Type: text/plain; format=flowed; charset=US-ASCII
Received-SPF: None (protection.outlook.com: durham.ac.uk does not designate
 permitted sender hosts)
SpamDiagnosticOutput: 1:99
SpamDiagnosticMetadata: NSPM
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 27 Mar 2018 22:06:20.9897 (UTC)
X-MS-Exchange-CrossTenant-Network-Message-Id: 5b6a3d49-4729-42ef-2961-08d5942ef987
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 7250d88b-4b68-4529-be44-d59a2d8a6f94
X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM5PR0602MB2802
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

NFS mounts stopped working on one of my computers after a kernel update 
from 4.15.3 to 4.15.4. I traced the problem to the commit
[46e8d06e423c4f35eac7a8b677b713b3ec9b0684] crypto: hash - prevent using 
keyed hashes without setting key
and a later kernel with this patch reverted works normally.

The problem seems to be related to kerberos as the mount fails when the 
keytab is present, but works if I rename the keytab file. This is true 
even though the mount is with sec=sys . The mount should also work with 
sec=krb5 but that also fails in the same way. When the mount fails there 
are errors in dmesg like
[ 1232.522816] gss_marshal: gss_get_mic FAILED (851968)
[ 1232.522819] RPC: couldn't encode RPC header, exit EIO
[ 1232.522856] gss_marshal: gss_get_mic FAILED (851968)
[ 1232.522857] RPC: couldn't encode RPC header, exit EIO
[ 1232.522863] NFS: nfs4_discover_server_trunking unhandled error -5. 
Exiting with error EIO
[ 1232.525039] gss_marshal: gss_get_mic FAILED (851968)
[ 1232.525042] RPC: couldn't encode RPC header, exit EIO

 	Michael Young