Langue: en

Version: 2010/04/24 (fedora - 01/12/10)

Section: 5 (Format de fichier)


slapo-constraint - Attribute Constraint Overlay to slapd




The constraint overlay is used to ensure that attribute values match some constraints beyond basic LDAP syntax. Attributes can have multiple constraints placed upon them, and all must be satisfied when modifying an attribute value under constraint.

This overlay is intended to be used to force syntactic regularity upon certain string represented data which have well known canonical forms, like telephone numbers, post codes, FQDNs, etc.

It constrains only LDAP add, modify and rename commands and only seeks to control the add and replace values of modify and rename requests.

No constraints are applied for operations performed with the relax control set.


This slapd.conf option applies to the constraint overlay. It should appear after the overlay directive.
constraint_attribute <attribute_name>[,...] <type> <value> [<extra> [...]]
Specifies the constraint which should apply to the comma-separated attribute list named as the first parameter. Five types of constraint are currently supported - regex, size, count, uri, and set.

The parameter following the regex type is a Unix style regular expression (See regex(7) ). The parameter following the uri type is an LDAP URI. The URI will be evaluated using an internal search. It must not include a hostname, and it must include a list of attributes to evaluate.

The parameter following the set type is a string that is interpreted according to the syntax in use for ACL sets. This allows to construct constraints based on the contents of the entry.

The size type can be used to enforce a limit on an attribute length, and the count type limits the number of values of an attribute.

Extra parameters can occur in any order after those described above.

<extra> : restrict=<uri>
This extra parameter allows to restrict the application of the corresponding constraint only to entries that match the base, scope and filter portions of the LDAP URI. The base, if present, must be within the naming context of the database. The scope is only used when the base is present; it defaults to base. The other parameters of the URI are not allowed.

Any attempt to add or modify an attribute named as part of the constraint overlay specification which does not fit the constraint listed will fail with a LDAP_CONSTRAINT_VIOLATION error.


 overlay constraint
 constraint_attribute jpegPhoto size 131072
 constraint_attribute userPassword count 3
 constraint_attribute mail regex ^[[:alnum:]]$
 constraint_attribute title uri
 constraint_attribute cn,sn,givenName set
   "(this/givenName + [ ] + this/sn) & this/cn"
A specification like the above would reject any mail attribute which did not look like <alpha-numeric string> It would also reject any title attribute whose values were not listed in the title attribute of any titleCatalog entries in the given scope. (Note that the "dc=catalog,dc=example,dc=com" subtree ought to reside in a separate database, otherwise the initial set of titleCatalog entries could not be populated while the constraint is in effect.) Finally, it requires the values of the attribute cn to be constructed by pairing values of the attributes sn and givenName, separated by a space, but only for entries derived from the objectClass inetOrgPerson.


default slapd configuration file


slapd.conf(5), slapd-config(5),


This module was written in 2005 by Neil Dunbar of Hewlett-Packard and subsequently extended by Howard Chu and Emmanuel Dreyfus. OpenLDAP Software is developed and maintained by The OpenLDAP Project <>. OpenLDAP Software is derived from University of Michigan LDAP 3.3 Release.