[Samba] Guest access broken for Win7 between 3.3.8 and 3.5.4?

[R. B. Letsinger]

I've been running samba on RHEL5 for the past couple of years with XP
clients. Late last year, in order to support new Win7 clients, I upgraded
from samba-3.0.33 packages to samba3x-3.3.8 (from the Red Hat-managed
configuration tree) and after some struggles got everything working. But now
after upgrading to samba3x-3.5.4 I am only able to connect as a known user
and not as a guest.

Relevant configuration details from smb.conf:

[global]
security=user
encrypt passwords = yes
passdb backend = smbpasswd
smb passwd file = /etc/samba/smbpasswd
guest account = gstuser
server signing = auto
map to guest = Bad User
log level = 2
wide links = no
follow symlinks = no
client ntlmv2 auth = yes
client signing = mandatory
...

[guest_share]
guest only = yes
path = <path with sufficient permissions>
read only = no

When I attempt to map this share on the Win7 side I get an error dialog
stating "The specified network drive is no longer available".
If I try to connect a similar already-mapped share on the Win7 side I get an
error dialog stating "The local device name is already in use."
I haven't been able to figure out how to get any further detail on the
Windows side.

On the Linux side, things appear to progress as expected: the original user
is unrecognized, is then mapped to guest, but then I get a getpeername
failed error:

...
2011/05/04 20:21:22.054326,  2] smbd/sesssetup.c:1390(setup_new_vc_session)
  setup_new_vc_session: New VC == 0, if NT4.x compatible we would close all
old resources.
[2011/05/04 20:21:22.054791,  2] auth/auth.c:314(check_ntlm_password)
  check_ntlm_password:  Authentication for user [CLIENTUSER] -> [CLIENTUSER]
FAILED with error NT_STATUS_NO_SUCH_USER
[2011/05/04 20:21:22.057474,  1] smbd/service.c:1070(make_connection_snum)
  CLIENTMACHINENAME (nnn.nnn.nnn.nnn) connect to service guest_share
initially as user gstuser (uid=nnn, gid=nnnn) (pid 31025)
[2011/05/04 20:21:22.057875,  0] lib/util_sock.c:474(read_fd_with_timeout)
[2011/05/04 20:21:22.058225,  0]
lib/util_sock.c:1432(get_peer_addr_internal)
  getpeername failed. Error was Transport endpoint is not connected
  read_fd_with_timeout: client 0.0.0.0 read error = Connection reset by
peer.
[2011/05/04 20:21:22.058376,  1] smbd/service.c:1251(close_cnum)
  CLIENTMACHINENAME (nnn.nnn.nnn.nnn) closed connection to service
guest_share
[2011/05/04 20:21:42.040820,  1] smbd/server.c:240(cleanup_timeout_fn)
  Cleaning up brl and lock database after unclean shutdown
...


As I say, all works fine with the same Win7 client machine when the server
is running samba3x-3.3.8, but gives the above behavior when I upgrade to
samba3x-3.5.4. (Staying at 3.3.8 is not optimal because I am in an
environment where I need to keep up-to-date with CVEs.) If I
authenticate via the guest uname/pwd, I am also able to connect -- just not
as an unknown user.

Of possible relevance is that I'm not running nbmd, which I haven't need
to-date.

The change log for the latest samba3x package mentions that SPNEGO parsing
was fixed between the two releases and I'm wondering if that could be
implicated.

Any thoughts?