Re: (ITS#6825) unique_uri filter reaching beyond its intended target

[hyc@symas.com]

subbarao@computer.org wrote:
> Full_Name: Kartik Subbarao
> Version: 2.4.23
> OS: Debian Linux 5.0.5
> URL: ftp://ftp.openldap.org/incoming/
> Submission from: (NULL) (76.99.175.5)
>
>
> I have the uniqueness overlay configured as follows in slapd.conf:
>
> overlay unique
> unique_uri ldap:///?gidNumber?sub?(objectClass=posixGroup)
>
> The policy I want to enforce is that all posixGroup entries must have a unique
> gidNumber attribute. At the same time, I want to *allow* non-posixGroup entries
> (such as inetOrgPerson) to have the same gidNumber attribute that a posixGroup
> entry has. This is so that a user can have a login group id set to that of an
> existing group.
>
> With the above configuration in place, if I create a posixGroup entry with
> gidNumber 389, and then try to add a gidNumber attribute of 389 to an
> inetOrgPerson entry, the operation fails with a constraint error "some
> attributes not unique".
>
> As I read the manpage for slapo-unique, the unique_uri filter seems to support
> the functionality that I want:
>
> =====
> The filter component causes the domain to apply uniqueness constraints only to
>     matching objects. e.g. ldap:///?cn?sub?(sn=e*) would require unique cn
> attributes for
> all objects in the subtree of the back-end database whose sn starts with an e.
> =====
>
> I'm inferring from this that uniqueness constraints on the cn attribute would
> *not* be applied to objects that don't match the filter. But that doesn't seem
> to be happening here. Is this a bug in the uniqueness overlay or am I not
> understanding the implementation?

Looks like a bug, the filter check is only implemented for Add operations, not 
for Modify or ModDN.

In the meantime, as a workaround you should simply use a more fully qualified 
URI. Restrict the URI to the ou containing your posixGroup entries. Since user 
names and group names are separate name spaces in POSIX, you cannot store them 
both in the same branches of a DIT anyway.

-- 
   -- Howard Chu
   CTO, Symas Corp.           http://www.symas.com
   Director, Highland Sun     http://highlandsun.com/hyc/
   Chief Architect, OpenLDAP  http://www.openldap.org/project/