[Samba] Samba 4 with sssd - primary Windows group membership not honored

Joseph Dickson jdickson at evolvetsi.com
Wed Mar 23 20:16:56 UTC 2016

> OK, you should use the standard 'rwx' permissions *or* ACLs, not both. If
> you create a directory on Unix that you want to share, set the owner:group
> to root:'Domain Admins' and permissions to 0770. You will then be able to
> set the permissions from windows or with setfacl on the Unix machine, you
> do not need the 'force group' lines in smb.conf, there is a wiki page for
> this, see here:
> https://wiki.samba.org/index.php/Shares_with_Windows_ACLs

I've tried following this page, and have not managed to have any luck.  I
even figured out the new syntax to add SeDiskOperatorPrivilege (net sam as
opposed to net rpc.. at least that's the command that ended up working..
net rpc always returned permission denied)

As soon as I try to set the Windows ACLs, I lose access to the folder
unless I'm defined as an admin user.  The first step that I try to do is to
set the root share permissions, and I remove everything except a full
control entry for Domain Admins (the domain group, not the Unix
Group\Domain Admins that it shows up with by default -- I remove that
one).  As soon as I hit OK, I lose access to the share.

On a Domain member you do not need sssd, winbind will do everything that
> sssd does, but on an AD DC it is a bit different, winbind there ignores all
> the RFC2307 attributes except for uidNumber & gidNumber.

I will try setting up a test server that uses winbind for nss instead of
sssd, but it doesn't seem like that's the problem as wbinfo and sssd (via
getent) are returning the same UID/GID numbers.  I don't have uid/gid
attributes added to my active directory schema, so it's using the
algorithmic method of computing them based on SID..

Samba only recommends using winbind, sssd is not supplied or supported by
> Samba.
> I don't know if you have read the Samba wiki pages, there is a lot of info
> about using Samba, it starts here:
> https://wiki.samba.org/index.php/Main_Page

Yes I've definitely spent quite a bit of time looking through the wiki
pages and other documentation sources.. unfortunately many times they
haven't been updated for new command syntaxes, and there is very little
information that digs into what's going on behind the scenes so it's pretty
tough to connect the dots yourself.

What I'm trying to achieve is as close to a drop in replacement for an MS
fileserver as possible -- all access managed by NT ACLs rather than posix.
I'm unclear how I can get this functionality without being forced to allow
world writeable at the posix level...

I'll work on creating a setup without sssd and see if the results vary, but
it doesn't feel like that's the issue..

*Joseph Dickson*
Director of IT Systems, Evolve Tele-Services, Inc.

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