[Samba] Rights issue on GPO
Achim Gottinger
achim at ag-web.biz
Sat Jun 25 10:35:09 UTC 2016
Am 25.06.2016 um 02:21 schrieb Achim Gottinger:
>
>
> Am 24.06.2016 um 23:16 schrieb Achim Gottinger:
>>
>>
>> Am 24.06.2016 um 22:57 schrieb Rowland penny:
>>> On 24/06/16 21:35, Achim Gottinger wrote:
>>>>
>>>>
>>>> Am 24.06.2016 um 21:24 schrieb Rowland penny:
>>>>> On 24/06/16 19:47, lingpanda101 at gmail.com wrote:
>>>>>> On 6/24/2016 11:40 AM, mathias dufresne wrote:
>>>>>>>
>>>>>>>
>>>>>>> 2016-06-24 15:24 GMT+02:00 lingpanda101 at gmail.com
>>>>>>> <mailto:lingpanda101 at gmail.com> <lingpanda101 at gmail.com
>>>>>>> <mailto:lingpanda101 at gmail.com>>:
>>>>>>>
>>>>>>> On 6/22/2016 12:21 PM, mathias dufresne wrote:
>>>>>>>
>>>>>>> 2016-06-22 16:37 GMT+02:00 L.P.H. van Belle
>>>>>>> <belle at bazuin.nl
>>>>>>> <mailto:belle at bazuin.nl>>:
>>>>>>>
>>>>>>> @Mathias,
>>>>>>>
>>>>>>> Pretty strange then, running some years like this
>>>>>>> without
>>>>>>> any problem.
>>>>>>> Yes we had few problems with "rights" in sysvol, but i
>>>>>>> fixed this all
>>>>>>> outside linux, and with that i mean. Changed rights
>>>>>>> from
>>>>>>> within windows or
>>>>>>> added registry changes or patches, or a local clean
>>>>>>> up of
>>>>>>> the policies.
>>>>>>>
>>>>>>> At the install of my DC2 i also synced the
>>>>>>> idmap.ldb, and
>>>>>>> then a
>>>>>>> net idmap flush on both servers to make my both dc's
>>>>>>> in sync.
>>>>>>> And i keep it in sync with my rsync/unison setup.
>>>>>>>
>>>>>>> All new added, but i'll keep an eye also in this and
>>>>>>> i'll
>>>>>>> recheck my logs.
>>>>>>> But i dont think i'll find anything here.
>>>>>>> I'll keep notice on your "workaround".
>>>>>>>
>>>>>>> Which backend are you using matias?
>>>>>>> Mine : (idmap config NTDOMAIN : backend = ad)
>>>>>>>
>>>>>>>
>>>>>>> Gr.
>>>>>>>
>>>>>>> Louis
>>>>>>>
>>>>>>>
>>>>>>> OK you keep idmap.ldb synched, that's what I missed
>>>>>>> until few
>>>>>>> days and was
>>>>>>> the reason that is was not working.
>>>>>>> Our choice to give each and users and groups into AD
>>>>>>> some xID
>>>>>>> is only to
>>>>>>> avoid usage of mapping. I expect the synchronization of
>>>>>>> idmap.ldb (if done
>>>>>>> often enough) would be sufficient. But I don't always like
>>>>>>> magic : )
>>>>>>>
>>>>>>> Thank you for precisions !
>>>>>>>
>>>>>>>
>>>>>>> Cheers all
>>>>>>>
>>>>>>>
>>>>>>> -----Oorspronkelijk bericht-----
>>>>>>> Van: samba [mailto:samba-bounces at lists.samba.org
>>>>>>> <mailto:samba-bounces at lists.samba.org>] Namens mathias
>>>>>>>
>>>>>>> dufresne
>>>>>>>
>>>>>>> Verzonden: woensdag 22 juni 2016 15:31
>>>>>>> Aan: lingpanda101 at gmail.com
>>>>>>> <mailto:lingpanda101 at gmail.com>
>>>>>>> CC: samba
>>>>>>> Onderwerp: Re: [Samba] Rights issue on GPO
>>>>>>>
>>>>>>> @LPH van Belle
>>>>>>> I did tried (and still use) "acl_xattr:ignore
>>>>>>> system
>>>>>>> acls = yes" as shown
>>>>>>> on the first mail of that thread. And even using
>>>>>>> that
>>>>>>> rights errors on
>>>>>>>
>>>>>>> GPO
>>>>>>>
>>>>>>> files _are_ an issue. Otherwise that thread
>>>>>>> won't have
>>>>>>> been opened of
>>>>>>> course : )
>>>>>>>
>>>>>>> Regarding how we decided to workaround almost
>>>>>>> definitively with that was
>>>>>>> to
>>>>>>> give every users and groups in AD some xID, also
>>>>>>> those
>>>>>>> in CN=Builtin and
>>>>>>> CN=Users. We also cleaned our idmap.ldb to keep
>>>>>>> inside
>>>>>>> only special users
>>>>>>> /
>>>>>>> groups (as "local system" / S-1-5-18, "guests" /
>>>>>>> S-1-5-32-546...).
>>>>>>> We also add some rsync to keep idmap.ldb
>>>>>>> synchronized
>>>>>>> on all our DC, for
>>>>>>> these special items have same mapped xID in case
>>>>>>> they
>>>>>>> are used (and so
>>>>>>> mapped).
>>>>>>>
>>>>>>> Doing that id mapper has no reason to define by
>>>>>>> itself
>>>>>>> some xID to users
>>>>>>> and groups contained into AD as they already
>>>>>>> have some
>>>>>>> xID.
>>>>>>>
>>>>>>> Until now it seems to work fine...
>>>>>>>
>>>>>>>
>>>>>>> 2016-06-22 15:09 GMT+02:00 lingpanda101 at gmail.com
>>>>>>> <mailto:lingpanda101 at gmail.com>
>>>>>>> <lingpanda101 at gmail.com
>>>>>>> <mailto:lingpanda101 at gmail.com>>:
>>>>>>>
>>>>>>> On 6/22/2016 8:53 AM, mj wrote:
>>>>>>>
>>>>>>>
>>>>>>> On 06/22/2016 02:44 PM,
>>>>>>> lingpanda101 at gmail.com
>>>>>>> <mailto:lingpanda101 at gmail.com> wrote:
>>>>>>>
>>>>>>> Why is is when I do a getfacl I do
>>>>>>> not see
>>>>>>> the mapping of BUILTIN
>>>>>>>
>>>>>>> like
>>>>>>>
>>>>>>> others?
>>>>>>>
>>>>>>> do you have winbind in /etc/nsswitch.conf?
>>>>>>>
>>>>>>> mj
>>>>>>>
>>>>>>>
>>>>>>> I also thought winbind was only necessary on
>>>>>>> member servers.
>>>>>>>
>>>>>>> --
>>>>>>> -James
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> --
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>>>>>>> URL and read the
>>>>>>> instructions:
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>>>>>>>
>>>>>>> --
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>>>>>>>
>>>>>>>
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>>>>>>>
>>>>>>>
>>>>>>> If I assign every user a UID and select groups a GID by
>>>>>>> utilizing
>>>>>>> rfc2307 on my DC's. Would I still benefit from keeping
>>>>>>> idmap.ldb
>>>>>>> synchronized? I'm thinking XID's are obsolete at that point?
>>>>>>>
>>>>>>>
>>>>>>> Only users and groups in AD will avoid id mapper by that
>>>>>>> workaround. But there are others accounts ("local system",
>>>>>>> "guest", "local administrator"...) all these accounts exist on
>>>>>>> MS Windows clients, and so they can all do stuff on Sysvol and
>>>>>>> so they can all go through id mapper.
>>>>>>>
>>>>>>> So no. There no way (for me at least :) to totally avoid id
>>>>>>> mapper and so you should keep idmap.ldb synched.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> -- -James
>>>>>>>
>>>>>>>
>>>>>>> -- To unsubscribe from this list go to the following URL
>>>>>>> and read the
>>>>>>> instructions: https://lists.samba.org/mailman/options/samba
>>>>>>>
>>>>>>>
>>>>>>
>>>>>> I'm in the process now of creating a script to sync idmap.ldb.
>>>>>> Does anyone have one at the moment? Is it best practice to stop
>>>>>> samba before replacing idmap.ldb on the additional DC's? My
>>>>>> script will currently watch for any idmap.ldb changes and create
>>>>>> a hot backup if a change is detected. It will then send to the
>>>>>> other DC's via rsync. I'm thinking starting and stopping samba
>>>>>> isn't ideal during production hours.
>>>>>>
>>>>>
>>>>> If you are running Samba >= 4.2.0 with the separate 'winbindd'
>>>>> binary, there is no reason to sync idmap.ldb. Syncing idmap was/is
>>>>> only required if you use 'winbind' that is built into the 'samba'
>>>>> binary.
>>>>>
>>>>> Rowland
>>>>>
>>>>>
>>>> Hello Rowland,
>>>>
>>>> If you take an look on your sysvol rights there are two still
>>>> unresoved groups SECURITY\Local System and SECURITY\Autheticated
>>>> Users. These show up with gid's from idmap.ldb in the acl list and
>>>> therefore can not be mapped during rsync. So at least these two
>>>> groups need idntical mapping on all dc's. It is however not
>>>> neccessary to keep idmap in sync as long as no ther security groups
>>>> are used.
>>>>
>>>> achim~
>>>>
>>>
>>> Yes I know, but each DC knows who they are and as they are members
>>> of the 'SECURITY' domain, they aren't mapped to the DOMAIN or BUILTIN.
>>>
>>> Rowland
>>>
>>>
>> If the gid used for "Authenticated Users" on the source server (dc1)
>> ist used for some "random group" on the target server (dc2), the read
>> right on sysvol for authenticated users will instead be given to
>> "random group". This can result in users not a member of "random
>> group" will not be able to access content on sysvol. Therefore it is
>> mandatory that these security groups are mapped to the same gid on
>> all dc's the sysvol conted is replicated.
>>
> This was an issue i ran into back on samba 4.0/4.1. Mapping BUILTIN in
> 4.2 has no impact but I assume the ACL's are read from the
> security.NTACL xattr so "Authenticated Users" should always have
> access because the xattr stores SID's and not the xid's. xattrs should
> be replicated with rsync without any mapping required.
Did an short test if proper posix uid/gid mapping is required for sysvol
to work.
Since vfs_acl_xattr is in use samba is said to keep the posix acl's in
sync with the acl's stored in the security.NTACL xattr object.
(https://www.samba.org/samba/docs/man/manpages/vfs_acl_xattr.8.html)
If i sync from an dc with different mappings in idmap.ldb the posix
acl's seem to have precedence over the xattr values, so they can mess up
things in an way that some security groups can gain read or ever write
rights because of the different mappings.
An easy fix is adding
acl_xattr:ignore system acls = Yes
to the sysvol section in smb.conf. Posix ACL's are now ignored and only
the ACL's from the xattr are used.
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