[Pkg-samba-maint] Bug#474108: Back on bug #474108

[Josip Rodin]

On Tue, Jan 06, 2009 at 06:43:20AM +0100, Christian Perrier wrote:
> Well, from what I see, it is absolutely confirmed that you reach the
> share as user joy and the last line of the log confirms that.
> 
> It is then more and more likely that this falls down in the category
> of several bugs related to "valid users" handling between 3.0.23 and
> 3.0.25.
> 
> The right confirmation can only come by testing with a more recent
> version (such as a backported 3.2: I will maybe finally provide one as
> we unofficially provide backported 3.2.x, with x>5 for lenny,
> already).
> 
> Of course, I understand that upgrading a PDC might be somewhat tricky
> for you. Can't you duplicate the PDC configuration to a test machine
> that could run lenny or unstable?

In the meantime I upgraded the entire domain to the new lenny Samba - it was
painful in the process because the old 3.0 servers started somehow applying
new access logic towards the first 3.2 BDC and users complained about not
being able to access. The new Samba, however, had considerably more useful
logs and based on reading them I think I found the original problem:

My users had something like this in LDAP:

dn: cn=Pero Peric,ou=users,dc=imago,dc=hr
uid: pperic
sambaSID: S-1-5-21-145766654-2861277506-3272706772-
sambaPrimaryGroupSID: S-1-5-21-145766654-2861277506-3272706772-513

As it turns out, this was a blatant lack of understanding of what the
sambaSID field is supposed to be - a unique identifier of the *user* object,
*NOT* simply a pointer to the unique identifier of the domain object.
This faulty mapping seemed to cause the Samba servers to think that all
users had all the privileges of the root object, probably related to the
fact that I had a cn=root user in LDAP with sambaSID
S-1-5-21-145766654-2861277506-3272706772-0 - I no longer have the exact
logs to demonstrate, sorry. In particular this new debugging helped me:

[2009/06/12 10:48:43,  3] lib/util_seaccess.c:se_access_check(252)
  se_access_check: user sid is S-1-5-21-145766654-2861277506-3272706772-1001000
  se_access_check: also S-1-22-2-1000
  se_access_check: also S-1-1-0
  se_access_check: also S-1-5-2
  se_access_check: also S-1-5-11
  se_access_check: also S-1-22-2-4
  se_access_check: also S-1-22-2-20
  se_access_check: also S-1-22-2-24
  se_access_check: also S-1-22-2-25
  se_access_check: also S-1-22-2-29
  se_access_check: also S-1-22-2-40
  se_access_check: also S-1-22-2-44
  se_access_check: also S-1-22-2-46
  se_access_check: also S-1-22-2-100
  se_access_check: also S-1-22-2-2000

(This is from a current, fixed session... hopefully! :)

The origin of this mistake was in the blatant inadequacy of the Samba
documentation. After some more Googling, I found this very helpful page:

https://people.chem.umass.edu/wiki/index.php?title=LDAP_Schema_and_Fields