LDAP User Registry

3.0

To configure an LDAP user registry, you must specify the base distinguished name, host, LDAP type, port number, and realm attributes. Most LDAP servers require bind credentials to authenticate a client to the server.

To bind with simple authentication, the bind distinguished name and password are specified in the ldapRegistry element. The following example shows a simple configuration that uses the IBM Tivoli Directory Server as an LDAP user registry.

You can use the securityUtility encode command to encode the bindPassword password for you. When you run the securityUtility encode command, you either supply the password to encode as an input from the command line or, if no arguments are specified, the command prompts you for the password. The command then outputs the encoded value. Copy this encoded value output by the command, and use this value for the bindPassword password.

For more information on troubleshooting LDAP, see Troubleshooting LDAP.

You can customize the group and user filters to include custom classes or attributes in searches of an LDAP user registry. The configuration for specifying filters varies depending on the LDAP type you specify. Each LDAP type has a different set of filter properties. For more information about the LDAP type, see Feature configuration elements. Use the %v variable for attribute value assertions that you want to replace at run time with a particular login name or group name. The following example shows custom and group filters that are specified for the IBM Tivoli Directory Server LDAP type.

To enable a secure connection to an LDAP server for encrypted communication with TLS or SSL protocols, configure the ldapRegistry element to enable Lightweight Directory Access Protocol Over Secure Socket Links (LDAPS). Set the sslEnabled attribute to true and the sslRef attribute to your ssl id value. To enable a secure TLS or SSL connection, you must configure these connections in the ssl element. For more information about TLS and SSL configurations, see SSL Repertoire.

The following example shows both the ldapRegistry element and the ssl element that the LDAP connection references. In the ssl element, the id parameter identifies the configuration so that it can be referenced by the sslRef parameter of the ldapRegistry element. The keyStoreRef and trustStoreRef parameters establish the data sources that are used in the TLS or SSL handshake, which enables a secure connection.

Alternatively, you can enable the SSL configuration that is used to connect to the LDAP server without specifying the sslRef attribute. When the sslEnabled attribute is set to true and the sslRef attribute is not specified, the SSL code looks for an outbound filter that matches the LDAP host and port. If no matching filter exists, the SSL outbound default is used.

In the following example, SSL is enabled but the sslRef attribute is not specified, so LDAP uses the LdapSSLSettings SSL configuration, which specifies the same host and port as the ldapRegistry configuration.

You can specify an LDAP entity type to configure support for custom or non-default object classes. An entity type groups different object classes as a single entity so that the server recognizes them under the same entity name. You can also customize the search base for any entity type to improve search times for the classes it contains. If you create custom object classes for users or groups, update your group and user filters to include the new classes. Use LDAP entities to specify multiple search bases instead of creating multiple LDAP registries with different baseDNs for the same LDAP server.

The following example shows entity types for users and groups, with custom search bases.

The user and group filters include the custom object classes. Although this example shows the configuration for the IBM Tivoli Directory Server LDAP type, all LDAP types support the userFilter and groupFilter attributes.

In the previous example, the values for ObjectClass include inetorgperson or groupofnames. If the correct ObjectClass or ObjectCategory value is not defined, a ClassCastException can occur, as shown in the following example.

In other cases where the ObjectClass is not properly defined, the user might not be found or a request to getSecurityName might return an empty string.

A searchBase specifies the sub tree of the LDAP server for the search call of the given entity type, which overrides the baseDN in search operations. For example, if the baseDN is o=acme.com,c=us and the search base for the PersonAccount entity type is defined as ou=users,o=acme.com,c=us, then all search calls for PersonAccount are made under ou=users,o=ibm,c=us sub tree. Calls to other sub trees, such as ou=iThings,o=ibm,c=us, are ignored.

LDAP user registries are federated by default. If you configure more than one LDAP user registry in your server.xml file, then the user registries are automatically federated into a common user registry. Ensure that the users are unique across all federated repositories, otherwise the user registry operations are not successful. When you use multiple federated LDAP repositories, each repository must define a unique baseDN attribute.

You can adjust the configuration of federated registries when the Federated User Registry feature is enabled by specifying the federatedRepository element. If you enable the LDAP User Registry feature version 3.0 or later, the Federated User Registry feature is enabled by default. Otherwise, you must manually enable the Federated User Registry feature to use the federatedRepository element.

If the federatedRepository element is specified to configure the participatingBaseEntry and primaryRealm elements, then the user registry operations are performed only on the repositories that are defined in the primaryRealm element. You can define the input and output property mappings for different user registry APIs under the primaryRealm element.

The following example shows two LDAP registries that are automatically federated, with configuration that is specified in the federatedRepository element.

The name attribute for the ldapRegistry element is optional. If this attribute is specified, the value of the name attribute in the participatingBaseEntry element must match the value of the name attribute in the ldapRegistry element. If the name attribute in the ldapRegistry element is not specified, the value of the name attribute in the participatingBaseEntry element must match the value of the baseDN attribute in the ldapRegistry element.

Each of these options is demonstrated on one of the participatingBaseEntry element configurations in the previous example.

You can also federate LDAP user registries with basic or custom user registries. The participating base entry for a user registry is defined by the participatingBaseEntry element. The participating base entry value for a custom or basic user registry is the o organization attribute set to equal the realm name of that user registry. For an LDAP user registry, the realm name is the base distinguished name from the LDAP user registry configuration. To verify that a user is unique in the common user registry, every search request searches all federated user registries. By default, all federated user registries must return successfully or the request fails.

The following example shows a basic user registry that is federated with an LDAP user registry, with the configuration specified in the federatedRepository element. Set the allowOpIfRepoDown attribute on the primaryRealm subelement to true to avoid failures if any user registry is unavailable.

For more information, see User Registry Federation.

To configure Kerberos bind authentication for LDAP servers, you must configure the bind authentication mechanism and the Kerberos principal on the ldapRegistry element, as shown in the following example:

The Kerberos principal is specified by the required krb5Principal attribute. You must set the bindAuthMechanism attribute to the GSSAPI value. This bind authentication mechanism is an alternative to the simple bind authentication mechanism, which uses a bind distinguished name and a bind password.

The krb5TicketCache attribute is optional and specifies the location of a ccache file, which is a credential cache file. The credentials in a ccache file can expire. When the krb5TicketCache attribute is specified and the principal is authenticated, the Kerberos service automatically attempts to renew the credentials before they expire.

Alternatively, you can specify the kerberos element in your server.xml file to configure Kerberos authentication for all features that use Kerberos credentials. This element configures a keytab file and a configuration file that can provide values to any Open Liberty features that use Kerberos credentials. The kerberos element is optional. For more information, see Kerberos authentication for Open Liberty.

If the krb5TicketCache attribute is not specified, Open Liberty resolves credential values from the Kerberos keytab file that is configured in the kerberos element. If no keytab file or krb5TicketCache attribute is configured, Open Liberty resolves credential values from the credential cache location that is specified by the Java SDK default settings. If both the krb5TicketCache attribute and the keytab attribute from the kerberos element are configured, both files are searched for credentials. Open Liberty searches first in the ccache file that is defined by the krb5TicketCache attribute and then in the keytab file that is defined by the kerberos element.

The krb5TicketCache attribute can be optionally specified for any feature that uses Kerberos credentials. If specified, this attribute takes precedence over any keytab and configFile values, Java SDK defaults, or operating system defaults. You might specify this attribute to configure credentials for a specific feature that are different from the configured values in the kerberos element.

To determine the causes of common problems and error messages that are associated with Kerberos authentication to LDAP servers, see Troubleshooting Kerberos authentication to LDAP servers.

To map attributes from a client X.509 certificate to attributes in your LDAP configuration, you can specify the CERTIFICATE_FILTER mapping mode.

If more than one LDAP entry matches the filter specification at run time, authentication fails because the result is an ambiguous match. The syntax for this filter is: LDAP attribute=${Client certificate attribute}

An example of a simple certificate filter is uid=${SubjectCN}.

You can also specify multiple properties and values as part of a certificate filter. The LDAP attribute of the filter specification depends on the schema that your LDAP server is configured to use. The client certificate attribute is one of the public attributes in your client certificate. The client certificate attribute must begin with a dollar sign and must be enclosed in braces, for example, ${SubjectCN}. The attributes are case-sensitive.

The LDAP attributes that are supported are uid, initials, sAMAccountName, displayName, distinguishedName, displayName, and description.

The client certificate attributes that are supported are ${SubjectCN}, ${SubjectDN}, ${IssuerCN}, ${IssuerDN}, and ${SerialNumber}.

The following example shows an LDAP configuration with the certificate filter mode that is enabled by the certificateMapMode attribute and a certificate filter that is specified by the certificateFilter attribute. In this certificate filter configuration, the value for the uid LDAP attribute to the ${SubjectCN} client certificate attribute.

For more information, see certificateFilter and certificateMapMode in LDAP User Registry

You can define mapping between LDAP attributes and the user registry attribute. After the mapping is configured, when you use the user registry attribute for any operation, the value is equivalent to the value of the LDAP attribute that is mapped.

In the following example, the mapping is defined for the userPassword LDAP attribute with the password user registry property in the server.xml file. The defaultValue attribute is optional. Mapping is defined for the externalId user registry attribute with the distinguishedName LDAP attribute for the PersonAccount entity type.

You can specify the configuration properties for LDAP failover servers. These are specified as backup servers that are prepared to switch automatically and seamlessly take over if the primary LDAP servers go offline. The following example shows you both the primary LDAP server and two sets of LDAP failoverServers elements specified in the ldapRegistry element. These failoverServers elements have multiple server elements that are defined within them. These server elements act as the backup servers in case the primary LDAP servers go offline.

For more information, see failoverServers in LDAP User Registry