[Samba] User home and shell lookup on a Samba AD DC

[Dennis Leeuw via samba]

Hi list,

I am probably overlooking something, but can not figure out what is
going on nor can I find something through google.

I just converted a Samba 4 PDC to Samba 4 AD DC (using the samba
provided tools). I hooked up a Linux laptop to the network configure
winbind, joined the domain and am able to login with my credentials from
Samba AD. However I can not seem to get it working on the machine
running the Samba AD.

The situation:
Samba AD DC:
Debian 8.7
Samba 4.2.14
smb.conf:
workgroup = DCDOMAIN
realm = dc-zone.my.domain
netbios name = PDC
server role = active directory domain controller
idmap_ldb: use rfc2307 = yes
dns forwarder = 192.168.1.1
winbind use default domain = yes
winbind nss info = rfc2307
allow trusted domain = yes
logon drive = z:
logon home = \\pdc\users\%U
# And then some shares...

Workstation:
Ubuntu 14.04 LTS
samba: 4.3.11
security = ads
realm = dc-zone.my.domain
workgroup = DCDOMAIN
netbios name = my-client
allow trusted domain = yes
winbind use default domain = yes
winbind nss info = rfc2307
idmap config DCDOMAIN: backend = ad
idmap config DCDOMAIN: schema_mode = rfc2307
idmap config DCDOMAIN: range = 500-799999
idmap config *: backend = ad
idmap config *: schema_mode = rfc2307
idmap config *: range = 800000-999999

An (simpified) example user entry from the samba LDAP looks like this:
dn: cn=username,CN=Users,DC=....
cn: username
unixHomeDirectory: /home/group/username
displayName: user A
loginShell: /bin/bash
uidNumber: 666
gidNumber: 999

/etc/nsswitch.conf on both machines has:
passwd: compat winbind
group: compat winbind
shadow: compat winbind

On the workstation winbind is running as a standalone /usr/sbin/winbind
and on the samba AD server /usr/sbin/winbind is running as a subprocess
of /usr/sbin/samba.

Running wbinfo -i on the workstation shows:
username:*:666:999::/home/group/username:/bin/bash

Running wbinfo -i on the Samba AD server shows:
username:*:666:999:user A:/home/DCDOMAIN/username:/bin/false

getent on both machines shows only the local passwd and group stuff,
while id on both shows:
uid=666(username) gid=999(group) groups=555(anothergroup),....

On the workstation I can login through login and through sshd, on the
server I can (of course) not since the shell is /bin/false.

Adding the idmap config settings to the server does not solve the problem.
Adding security = ads to the server config makes sure samba does not start.
Adding "template shell = /bin/bash" to the server configuration makes
wbinfo output show /bin/bash as shell, and I can login.

So somehow the /usr/sbin/winbind samba subprocess retrieves different
information from the LDAP database. But I can´t figure out what I am
doing wrong (my assumption is that it is somewhere in the
configuration). Can someone point me in the right direction?
Questions:
- Why doesn't the server config retrieve the shell and home directory
from LDAP?
- Why doesn't the workstation config retrieve the displayName field from
LDAP (although this is harmless for now)?

With kind regards,

Dennis Leeuw

--
DBG-ICT
UMC Utrecht


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[Rowland Penny via samba]

On Mon, 20 Mar 2017 13:02:38 +0100
Dennis Leeuw via samba <sa...@lists.samba.org> wrote:

> Hi list,
>
> I am probably overlooking something, but can not figure out what is
> going on nor can I find something through google.
>
> I just converted a Samba 4 PDC to Samba 4 AD DC (using the samba
> provided tools). I hooked up a Linux laptop to the network configure
> winbind, joined the domain and am able to login with my credentials
> from Samba AD. However I can not seem to get it working on the
> machine running the Samba AD.
>
> The situation:
> Samba AD DC:
> Debian 8.7
> Samba 4.2.14

If you look here:

https://downloads.van-belle.nl/samba4/samba-4.6.0/

You will find 4.6.0 amd64 debs, Samba does not support 4.2.x anymore,
though this doesn't stop you using it.

> smb.conf:

> winbind use default domain = yes
> winbind nss info = rfc2307
> allow trusted domain = yes
> logon drive = z:
> logon home = \\pdc\users\%U

You might as well remove those lines, they do not work on a DC (Also
please do not call your DC a PDC, it is confusing)

> Running wbinfo -i on the workstation shows:
> username:*:666:999::/home/group/username:/bin/bash
>
> Running wbinfo -i on the Samba AD server shows:
> username:*:666:999:user A:/home/DCDOMAIN/username:/bin/false
>
> getent on both machines shows only the local passwd and group stuff,

Ah, but is this 'getent passwd' or 'getent passwd username' ?

By default, winbind does not enumerate users and groups.

> while id on both shows:
> uid=666(username) gid=999(group) groups=555(anothergroup),....
>
> On the workstation I can login through login and through sshd, on the
> server I can (of course) not since the shell is /bin/false.
>
> Adding the idmap config settings to the server does not solve the
> problem.

They do nothing on A DC unless you upgrade to 4.6.0 and then they will
stop 'samba' starting.

>Adding security = ads to the server config makes sure samba
> does not start. Adding "template shell = /bin/bash" to the server
> configuration makes wbinfo output show /bin/bash as shell, and I can
> login.

Winbind on a DC, does not extract the users unix home dir and login
shell, you have to use template lines in smb.conf.

Rowland