[Samba] Samba AD: gidNumber?

Thu Oct 29 20:22:48 UTC 2015

On 29.10.2015 20:52, Rowland Penny wrote:
> On 29/10/15 19:27, Viktor Trojanovic wrote:
>>
>>
>> On 29.10.2015 18:49, Rowland Penny wrote:
>>> On 29/10/15 17:27, Viktor Trojanovic wrote:
>>>>
>>>>
>>>> On 29.10.2015 17:54, Rowland Penny wrote:
>>>>> On 29/10/15 16:21, Viktor Trojanovic wrote:
>>>>>>
>>>>>>
>>>>>> On 27.10.2015 16:16, Rowland Penny wrote:
>>>>>>> On 27/10/15 14:58, Viktor Trojanovic wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>> On 27.10.2015 13:54, Rowland Penny wrote:
>>>>>>>>> [...]
>>>>>>>>>> Yes, I meant the administrator. I did your suggested change 
>>>>>>>>>> on my member server and restarted it. 'getent passwd 
>>>>>>>>>> administrator' is still not returning anything, though. Or is 
>>>>>>>>>> that the wrong way to check if it worked?
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> If you ran the same command on the DC, it will return 
>>>>>>>>> something, but on a member server it won't, because the range 
>>>>>>>>> you set in smb.conf is (if you followed the wiki, 10000-99999) 
>>>>>>>>> above '0' and anything that is outside the range is ignored. 
>>>>>>>>> This is not a problem, remember that Administrator is mapped 
>>>>>>>>> to root on the member server, so if you want to log into the 
>>>>>>>>> member server, you would so as root. From windows, 
>>>>>>>>> Administrator becomes root and carries out any changes etc as 
>>>>>>>>> root.
>>>>>>>>>
>>>>>>>>> Rowland
>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>> Ok, all understood, thank you. But how can I check if it worked 
>>>>>>>> with the users? I manually changed the Nisdomain and uidNumber 
>>>>>>>> for two users using ADUC (to 10001 and 10002, respectively), I 
>>>>>>>> restarted Samba (was this even necessary?), and getent passwd 
>>>>>>>> <username> will still not return anything.
>>>>>>>>
>>>>>>>> In other words, what is the quickest way to check if my member 
>>>>>>>> server setup worked out alright?
>>>>>>>
>>>>>>> OK, if you compiled samba yourself and you want to test getent 
>>>>>>> on the member server, see this that I posted earlier:
>>>>>>>
>>>>>>> https://lists.samba.org/archive/samba/2015-October/195319.html
>>>>>>>
>>>>>>> If you are using distro packages, the wiki pages should give you 
>>>>>>> a good idea of what you need.
>>>>>>>
>>>>>>> Rowland
>>>>>>>
>>>>>>>
>>>>>> So, I spent quite some time researching it all a bit more in 
>>>>>> depth but I get stuck at the same point, although I at least seem 
>>>>>> to have a better understanding of how things should be now.
>>>>>>
>>>>>> So, my smb.conf on the member server looks exactly like the one 
>>>>>> in the wiki, except that I also added ACL support as suggested on 
>>>>>> the wiki page "Shares with Windows ACLs". My filesystem is XFS 
>>>>>> and has ACL built-in.
>>>>>>
>>>>>> I do get proper results for wbinfo -u and wbinfo -g, but the id 
>>>>>> and getent commands just won't work. I'm trying it on users and 
>>>>>> groups that have a uidNumber or gidNumber defined, respectively.
>>>>>>
>>>>>> This is how my nsswitch.conf looks like:
>>>>>>
>>>>>> passwd: compat winbind
>>>>>> group: compat winbind
>>>>>> hosts:compat dns
>>>>>> networks: compat dns
>>>>>>
>>>>>> My Samba came from a package but I verified that 
>>>>>> libnss_winbind.so.2 is properly linked.
>>>>>>
>>>>>> smbd, nmbd and winbindd are properly started with no errors in 
>>>>>> the logs, I'm joined to the AD, I can browse the member server 
>>>>>> from my windows machine being logged in as Administrator. But I 
>>>>>> still can't seem to change ACLs on any objects in the share from 
>>>>>> within Windows, I'm getting error messages "Error when applying 
>>>>>> security" (I'm translating freely from German).
>>>>>>
>>>>>> Do you have any idea what's going wrong here?
>>>>>>
>>>>>> Viktor
>>>>>
>>>>> OK, If I remember correctly, we are talking about a domain member 
>>>>> here, not a DC. If you are using the default smb.conf from here:
>>>>>
>>>>> https://wiki.samba.org/index.php/Setup_Samba_as_an_AD_Domain_Member
>>>>>
>>>> No. I'm using the smb.conf from 
>>>> https://wiki.samba.org/index.php/Setup_a_Samba_AD_Member_Server
>>>>
>>>>> with the 'ad' setup from here:
>>>>>
>>>>> https://wiki.samba.org/index.php/Idmap_config_ad
>>>>>
>>>> Those lines are already implemented in the smb.conf retrieved from 
>>>> https://wiki.samba.org/index.php/Setup_a_Samba_AD_Member_Server
>>>
>>> OK, what is the difference between a 'domain member' and a 'member 
>>> server', well to be honest, not much. You can think of a 'domain 
>>> member' being the same as a normal windows workstation that a user 
>>> logs into and it doesn't share anything. You can turn a 'domain 
>>> member' into a 'member server' very easily, just make it share 
>>> something :-) if you share printers from it, it becomes a 'Print 
>>> Server' , add data shares and it becomes a 'File Server', I think 
>>> you get the idea here :-)
>>>
>>> Your smb.conf from the 'member server' page is equivalent to the one 
>>> you can create from the three pages I posted.
>>>
>>>>> with the acl support lines from here:
>>>>>
>>>>> https://wiki.samba.org/index.php/Shares_with_Windows_ACLs#ACL_support_on_domain_members 
>>>>>
>>>>>
>>>> Those exact 3 lines, yes.
>>>>> then getent should work, but they are a few caveats, the users 
>>>>> must have a uidNumber inside the range 10000-99999 and Domain 
>>>>> Users (at least) must have a gidNumber inside the same range. Any 
>>>>> users or groups outside this range will be ignored and *all* users 
>>>>> will be ignored if Domain Users either doesn't have a gidNumber or 
>>>>> it is outside the range.
>>>>>
>>>> The user I'm trying to return has a uidNumber of 10002, and Domain 
>>>> Users is set to gidNumber 10000. I have not set those attributes 
>>>> for other groups and did not expect them to show up with getent.
>>>>
>>>>> Time must be synchronised between the machines, within 5 mins if 
>>>>> remember correctly.
>>>> Time is synced and well within 5 mins. Kerberos would fail 
>>>> otherwise and I am able to request k-tickets for any user without 
>>>> issues.
>>>>> The domain member must be joined to the domain (obviously)
>>>> Of course.
>>>>> The domain member must be using the DC has its DNS server
>>>>>
>>>>> /etc/resolv.conf
>>>>> search samdom.example.com
>>>>> nameserver 192.168.0.3 <-- this is the ip of the DC
>>>>>
>>>> My DC has a fixed IP and that's exactly how my resolv.conf looks 
>>>> like, no other lines.
>>>
>>> Yes but does your 'member server' have a fixed ip ?
>>>
>>>>> You only need this in /etc/krb5.conf
>>>>>
>>>>> [libdefaults]
>>>>>         default_realm = SAMDOM.EXAMPLE.COM
>>>>>         dns_lookup_realm = false
>>>>>         dns_lookup_kdc = true
>>>>>
>>>> That's exactly what I have. As mentioned, Kerberos seems to work 
>>>> properly.
>>>>
>>>>> Ideally your domain member should have a fixed ip, but if you are 
>>>>> using dhcp, check that the ipaddress isn't 127.0.0.1 or even worse 
>>>>> 127.0.1.1. If you using Ubuntu with Network Manager, stop it using 
>>>>> dnsmasq.
>>>>>
>>>> See above.
>>>>> Check that pam is setup correctly, on debian you can do this by 
>>>>> running 'pam-auth-update'
>>>>>
>>>> I don't have pam setup since I don't need the users to log in to 
>>>> Linux. It is nowhere mentioned, neither on the wiki nor on the book 
>>>> that this is a prerequisite for getent to work.
>>>
>>> Applying Hand brake screeching to a halt :-D
>>>
>>> If pam is not set up you will not get 'getent' to work. Can you 
>>> please refresh my memory and tell me what OS you are using. Pam is 
>>> not required on a DC unless you require your users to actually log 
>>> into it, but it is definitely needed on a 'domain member' (or as you 
>>> call it, a 'member server')
>>>
>>> There is a mention of setting up PAM on the page you referred to:
>>>
>>> https://wiki.samba.org/index.php/Setup_a_Samba_AD_Member_Server#Setting_up_PAM_authentication 
>>>
>>>
>>> Though it is a bit unclear that it is required to make 'getent' 
>>> work, I will not update this page because there is a very good 
>>> chance it will get a massive overhaul soon, but I will look into 
>>> whether any other Pam info specifies that it is needed on a domain 
>>> member.
>>>
>>> Rowland
>>
>> Well, I'll be... I really didn't figure out that that was any kind of 
>> necessity. Since the getent checks on the wiki (and in my book) are 
>> performed before the comments about PAM, I thought that's just for 
>> special situations (such as needing users to log in on Linux). So 
>> you're saying I can't set my ACL's with domain users because of that?
>
> getent shows what the OS knows about a user, if it shows nothing, that 
> user is unknown to the OS and as such cannot own anything. On the DC, 
> this is not really a problem because the users are automatically given 
> an xidNumber and this is used instead and most people only use the DC 
> for authentication. You only need the libnss_winbind links and pam (or 
> something in its place) if you want your users to connect to the 
> member server.
>
>>
>> I guess my next project then is to figure out how to configure this 
>> on Alpine Linux which is what I'm using for my member server. While I 
>> can find packages for PAM, it seems that there is no pam_winbind 
>> module so I'm not sure where this leaves me. Any tips?
>
> Er, use Debian instead :-D
> I could give you instructions to set up a basic Samba domain member on 
> Debian that would only take you about 15mins and is guaranteed to work 
> (famous last words).
>
> Rowland
>
Haha :) I've already spent so much time on getting to know Arch and 
Alpine Linux in and out, with some Ubuntu on the side, just can't bother 
to add Debian to the list. But if I can't get neither to work, I'll 
reconsider. :)

I'll report back.. thanks again, and good night.

Viktor