[Samba] [EXT] Re: Samba 4 without winbind

Shannon Price pricesw at auburn.edu
Sun Sep 18 15:25:14 UTC 2022

I assume this is the Nov 2021 security guidance that you mention? I'll include the link for reference in the thread.


Could you tell that only from the version that I mentioned (4.11.6)?


-----Original Message-----
From: Andrew Bartlett <abartlet at samba.org> 
Sent: Sunday, September 18, 2022 4:16 AM
To: Shannon Price <pricesw at auburn.edu>; samba at lists.samba.org
Subject: [EXT] Re: [Samba] Samba 4 without winbind

CAUTION: Email Originated Outside of Auburn.

On Sat, 2022-09-17 at 15:17 +0000, Shannon Price via samba wrote:
> We support our Windows clients via Samba since the 1990s. Our main 
> infrastructure is NIS/NFS to support our servers and Linux clients.
> We have Samba using ADS for authentication for many years, but our 
> users and groups still come from NIS. Our last Samba server is running 
> on Ubuntu 18 (Samba 4.7.6) and is rock solid using smbd/nmbd.  Our 
> newest Samba server is running on Ubuntu 20.04 (Samba
> 4.11.6 - we found severe problems with the current versions: 
> and have pinned Samba at 4.11.6 for 
> now).  We're running it the same way we always have - the machine is 
> ADS joined (net join ads ....). I experimented with winbind for quite 
> a while, but we don't need AD groups or user attributes, so it seems 
> unnecessary and we couldn't get our NIS groups to work when we did 
> that even trying to monkey with nsswitch.conf using nis for groups.
> The problem now is only that I have full access to everything with 
> unqualfied names (\\SERVER\homes< file://SERVER/homes>  works), but 
> FQDN (\\server.domain.edu\homes<
> file://server.domain.edu/homes>)
>  doesn't work and the debug logs show that Samba wants winbind 
> whenever I talk to the server with FQDN.
> Logs with FQDN:
> [2022/09/17 08:40:16.941558,  0]
> ../../source3/auth/auth_winbind.c:120(check_winbind_security)
>   check_winbind_security: winbindd not running - but required as 
> [2022/09/17 08:40:16.943204,  2]
> ../../source3/auth/auth.c:343(auth_check_ntlm_password)
>   check_ntlm_password:  Authentication for user [USERNAME] -> 
> authoritative=1
> [2022/09/17 08:40:16.943300,  2]
> ../../auth/auth_log.c:635(log_authentication_event_human_readable)
> Logs without FQDN:
> (ipv4: connect to service USERNAME 
> initially as user USERNAME (uid=12345, gid=123) (pid 454545)
> [2022/09/17 10:15:38.595009,  0]
> ../../source3/param/loadparm.c:3358(process_usershare_file)

What you do is still possible, perhaps with some work (see the Nov 2021 security guidance as you have not applied those patches).

Just run winbindd but don't configure it in the smb.conf.  

We recogninise that for some the authentication is via AD but the authorization is via other methods specified in nsswitch.conf, and we now have tests specifically aimed at this.

Andrew Bartlett
Andrew Bartlett (he/him)      
Samba Development and Support, Catalyst IT - Expert Open Source Solutions

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