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From: Norman Elton <normelton@gmail.com>
To: linux-nfs@vger.kernel.org
Subject: Excessive group membership causes permission denied
Date: Mon, 18 Mar 2013 14:46:48 -0400	[thread overview]
Message-ID: <CAPCnwUeMeQuZo1ygbXAB-KXJbv71wtTsTbaELcT=ombWVSG4mg@mail.gmail.com> (raw)

There is a fairly well documented bug that we've run against. When
using Active Directory as a KDC, users with a large number of group
memberships can overrun a UDP packet, causing Kerberos to fall back to
TCP. When a user logs into the system, they have a kerberos ticket,
but get a "permission denied" when accessing the NFS share. We've
reproduced this by taking a functioning user, adding tons of group
membership. The error message pops right up.

The traditional fix is to set NO_AUTH_DATA_REQUIRED on the NFS
server's machine account, as explained here:
http://theether.net/kb/100205.

While this seems to work, it's a bit of a dirty hack. Any thoughts on
a root-cause? We're happy to serve as a guinea pig if anyone can point
us in the right direction.

Thanks,

Norman

                 reply	other threads:[~2013-03-18 18:46 UTC|newest]

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