[Samba] NSS interface lists all domain users but gives error on single user

[Giuseppe Sacco]

Hello Rowland

Il giorno mer, 17/10/2018 alle 21.28 +0100, Rowland Penny via samba ha
scritto:
[...]
> What does 'wbinfo -U 10182' return ?
> The last number should be 2182

root at kubuntu-test:~# wbinfo -U 10182
S-1-5-21-1076504413-1754488879-1808648030-2182
root at kubuntu-test:~# wbinfo -n 'AGENZIA\lorenam'
S-1-5-21-1076504413-1754488879-1808648030-2182 SID_USER (1)
root at kubuntu-test:~# getent passwd 'AGENZIA\lorenam'
root at kubuntu-test:~# 

> > I do not know how to better debug the problem: I have reised "log
> > level" in smb.conf but no logging is done during the getent
> > execution.
> > 
> 
> Bit lost myself here, why doesn't 'getent passwd username' return
> anything ?
> Is there anything like sssd running ?
> 
> Have you changed anything else ?

This is a new installation for testing purposes: there were no previous
installation, so nothing changed. sssd is not installed.

root at kubuntu-test:~# COLUMNS=80 dpkg -l | egrep samba\|winb\|sss
ii  libnss-winbind 2:4.7.6+dfsg amd64        Samba nameservice integration plu
ii  libpam-winbind 2:4.7.6+dfsg amd64        Windows domain authentication int
ii  libwbclient0:a 2:4.7.6+dfsg amd64        Samba winbind client library
ii  python-samba   2:4.7.6+dfsg amd64        Python bindings for Samba
ii  samba          2:4.7.6+dfsg amd64        SMB/CIFS file, print, and login s
ii  samba-common   2:4.7.6+dfsg all          common files used by both the Sam
ii  samba-common-b 2:4.7.6+dfsg amd64        Samba common files used by both t
ii  samba-dsdb-mod 2:4.7.6+dfsg amd64        Samba Directory Services Database
ii  samba-libs:amd 2:4.7.6+dfsg amd64        Samba core libraries
ii  samba-vfs-modu 2:4.7.6+dfsg amd64        Samba Virtual FileSystem plugins
ii  winbind        2:4.7.6+dfsg amd64        service to resolve user and group


even commenting out the lines about the rid idmap backend, and hence
defaulting to the "*" domain config that uses tdb, the mapping works.
wbinfo and tdb file display/contain the same mapping:

   #idmap config AGENZIA : backend = rid
   #idmap config AGENZIA : range = 8000-20000

# systemctl stop winbind smbd nmbd
# rm /var/cache/samba/gencache.tdb /var/cache/samba/netsamlogon_cache.tdb \
  /var/lib/samba/account_policy.tdb /var/lib/samba/group_mapping.tdb \
  /var/lib/samba/winbindd_cache.tdb /var/lib/samba/winbindd_cache.tdb.bak \
  /var/lib/samba/winbindd_idmap.tdb  /var/lib/samba/private/idmap2.tdb
# systemctl start winbind smbd nmbd

# getent passwd 'AGENZIA\lorenam'
# getent passwd | fgrep 'AGENZIA\lorenam'
AGENZIA\lorenam:*:3034:3004::/home/lorenam:/bin/bash

# wbinfo --uid-to-sid 3034
S-1-5-21-1076504413-1754488879-1808648030-2182
# tdbtool /var/lib/samba/winbindd_idmap.tdb show 'UID 3034\0'
key 9 bytes
UID 3034
data 47 bytes
[000] 53 2D 31 2D 35 2D 32 31  2D 31 30 37 36 35 30 34  S-1-5-21 -1076504
[010] 34 31 33 2D 31 37 35 34  34 38 38 38 37 39 2D 31  413-1754 488879-1
[020] 38 30 38 36 34 38 30 33  30 2D 32 31 38 32 00     80864803 0-2182

# wbinfo --sid-to-uid S-1-5-21-1076504413-1754488879-1808648030-2182
3034
# tdbtool /var/lib/samba/winbindd_idmap.tdb show 'S-1-5-21-1076504413-1754488879-1808648030-2182\0'
key 47 bytes
S-1-5-21-1076504413-1754488879-1808648030-2182
data 9 bytes
[000] 55 49 44 20 33 30 33 34  00                       UID 3034

So, I think this is not related to the mapping, but probably to libnss-
winbind.

Bye,
Giuseppe