Ubuntu Manpage: slapo-unique - Attribute Uniqueness overlay to slapd

Provided by: slapd_2.4.49+dfsg-2ubuntu1.10_amd64

NAME

       slapo-unique - Attribute Uniqueness overlay to slapd

SYNOPSIS

       /etc/ldap/slapd.conf

DESCRIPTION

       The  Attribute Uniqueness overlay can be used with a backend database such as slapd-mdb(5) to enforce the
       uniqueness of some or all attributes within a scope. This subtree defaults  to  all  objects  within  the
       subtree of the database for which the Uniqueness overlay is configured.

       Uniqueness  is  enforced  by  searching the subtree to ensure that the values of all attributes presented
       with an add, modify or modrdn operation are unique within the scope.  For  example,  if  uniqueness  were
       enforced for the uid attribute, the subtree would be searched for any other records which also have a uid
       attribute containing the same value. If any are found, the request is rejected.

       The  search  is  performed  using  the  rootdn  of the database, to avoid issues with ACLs preventing the
       overlay from seeing all of the relevant data. As such, the database must have a rootdn configured.

CONFIGURATION

These slapd.conf options apply to the Attribute Uniqueness overlay. They should appear after the overlay
directive.

unique_uri <[strict ][ignore ]URI[URI...]...>
Configure the base, attributes, scope, and filter for uniqueness checking. Multiple URIs may be
specified within a domain, allowing complex selections of objects. Multiple unique_uri statements
or olcUniqueURI attributes will create independent domains, each with their own independent lists
of URIs and ignore/strict settings.

Keywords strict and ignore have to be enclosed in quotes (") together with the URI.

The LDAP URI syntax is a subset of RFC-4516, and takes the form:

ldap:///[base dn]?[attributes...]?scope[?filter]

The base dn defaults to that of the back-end database. Specified base dns must be within the
subtree of the back-end database.

If no attributes are specified, the URI applies to all non-operational attributes.

The scope component is effectively mandatory, because LDAP URIs default to base scope, which is
not valid for uniqueness, because groups of one object are always unique. Scopes of sub (for
subtree) and one for one-level are valid.

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.

It is possible to assert uniqueness upon all non-operational attributes except those listed by
prepending the keyword ignore If not configured, all non-operational (e.g., system) attributes
must be unique. Note that the attributes list of an ignore URI should generally contain the
objectClass, dc, ou and o attributes, as these will generally not be unique, nor are they
operational attributes.

It is possible to set strict checking for the uniqueness domain by prepending the keyword strict.
By default, uniqueness is not enforced for null values. Enabling strict mode extends the concept
of uniqueness to include null values, such that only one attribute within a subtree will be
allowed to have a null value. Strictness applies to all URIs within a uniqueness domain, but some
domains may be strict while others are not.

It is not possible to set both URIs and legacy slapo-unique configuration parameters simultaneously. In
general, the legacy configuration options control pieces of a single unfiltered subtree domain.

unique_base <basedn>
This legacy configuration parameter should be converted to the base dn component of the above
unique_uri style of parameter.

unique_ignore <attribute...>
This legacy configuration parameter should be converted to a unique_uri parameter with ignore
keyword as described above.

unique_attributes <attribute...>
This legacy configuration parameter should be converted to a unique_uri parameter, as described
above.

unique_strict <attribute...>
This legacy configuration parameter should be converted to a strict keyword prepended to a
unique_uri parameter, as described above.

CAVEATS

       unique_uri cannot be used with the old-style of configuration, and vice versa.  unique_uri can  implement
       everything the older system can do, however.

       Typical  attributes  for the ignore ldap:///...  URIs are intentionally not hardcoded into the overlay to
       allow for maximum flexibility in meeting site-specific requirements.

       Replication and operations with manageDsaIt control  are  allowed  to  bypass  this  enforcement.  It  is
       therefore  important  that all servers accepting writes have this overlay configured in order to maintain
       uniqueness in a replicated DIT.

FILES