[Samba] Winbind and GPO access restrictions?

Patrick Goetz pgoetz at math.utexas.edu
Fri Oct 1 18:21:17 UTC 2021

On 10/1/21 12:52, Robert Marcano via samba wrote:
> On 10/1/21 12:02 PM, Patrick Goetz via samba wrote:
>> While most of my campus Samba projects are still going to need to play 
>> nice with at least sssd id mapping, I do have one project which, based 
>> on discussions on this list, I was planning to configure strictly with 
>> winbind, since the AD DC is going to be Samba and it's the rare luxury 
>> where I get to control everything.
>> However, a couple of days ago I had an anxiety-inducing thought.  This 
>> is a mixed windows/linux environment, and one of the features the end 
>> users would like and which I've already promised them is that the 
>> linux machines would have different access restrictions from the 
>> Windows desktops. The way I've been doing this with sssd is creating a 
>> GPO applied to the host (or set of hosts) which restricts access to a 
>> particular security group.
>> Reading through this page: https://wiki.samba.org/index.php/Group_Policy
>> it's not clear this would also be possible with winbind.  Would such a 
>> thing fall under the category of "smb.conf Policies"?  It doesn't seem 
>> like it, since smb.conf access restrictions are most aimed at share 
>> control.
> With winbind alone you will not be able to do that, you will need to use 
> classic Linux mechanism to control login (pam files editing for example) 
> and maybe automate the deployment on all machines by other means 
> (Ansible, Puppet, etc)
> Samba doesn't apply any GPO rules to Linux hosts. It is a sssd feature 
> to apply login restriction policies if enabled (and only a few of them 
> that make sense to Linux hosts)

Oh wow. So I guess winbind can not do everything sssd does, and I'm 
guessing that using idmap_sss doesn't help with this issue, either.

Looks like I'm back to using RFC 2307 mapping and doing what Rowland 
said not to do: just matching the UIDs/GIDs on the linux systems. But 
that's headache equivalent to using Ansible to copy around modified PAM 
configuration files and solves the other problem I have of at least one 
linux machine that needs file access being behind someone else's AD domain.

Now I'm mystified at how people are using newer versions of Samba in a 
mixed Windows/Linux environment. If your linux workstations (i.e. not 
fileservers) are bound to the domain, you most certainly want them to be 
using domain authentication restrictions and not some ad hoc thing you 
have to cobble together and deploy with CMS every time the directory 
changes. I guess this is the problem that RHEL idM solves by foresting 
with a Samba DC; no idea; I have no experience with this whatsoever.

Out of curiosity, is anyone out there using full blown sssd with a Samba 
version > 4.8?  Is that even a thing?

>> Thanks.

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