Linux CIFS NTLMSSP mount failing against win2k8

I've been playing with NTLMSSP today in CIFS, and have run across a
problem. The Session Setup using Raw NTLMSSP succeeds, but then afterward
the tree connect fails with STATUS_ACCESS_DENIED. The odd thing is that
if authenticate as the same user using krb5, then it works fine.
smbclient does SPNEGO encapsulated NTLMSSP and the tree connect it does
works fine as well.

Attached is a capture that shows two "mount attempts". The first one
fails (that the Linux CIFS one). The second succeeds -- that's the
Linux CIFS one.

The code I'm using is slightly modified so that the tree connect is
closer to identical to what smbclient does. That doesn't get around the
problem though. I assume that there must be something wrong with the
session setup, but since it succeeds it seems like it ought to work...

Does anyone have any clue as to what the problem is? Or does anyone
know how to make win2k8 tell me why it's refusing the tree connect? The
event viewer seems to be pretty useless for this, but maybe I'm just
not looking in the right place?

-- 
Jeff Layton <[email protected]>