Package org.springframework.security.ldap.authentication

Class LdapAuthenticationProvider

java.lang.Object
org.springframework.security.ldap.authentication.AbstractLdapAuthenticationProvider
org.springframework.security.ldap.authentication.LdapAuthenticationProvider
All Implemented Interfaces:
org.springframework.beans.factory.Aware, org.springframework.context.MessageSourceAware, AuthenticationProvider
public class LdapAuthenticationProvider extends AbstractLdapAuthenticationProvider
An AuthenticationProvider implementation that authenticates against an LDAP server.

There are many ways in which an LDAP directory can be configured so this class delegates most of its responsibilities to two separate strategy interfaces, LdapAuthenticator and LdapAuthoritiesPopulator.

LdapAuthenticator

This interface is responsible for performing the user authentication and retrieving the user's information from the directory. Example implementations are BindAuthenticator which authenticates the user by "binding" as that user, and PasswordComparisonAuthenticator which compares the supplied password with the value stored in the directory, using an LDAP "compare" operation.

The task of retrieving the user attributes is delegated to the authenticator because the permissions on the attributes may depend on the type of authentication being used; for example, if binding as the user, it may be necessary to read them with the user's own permissions (using the same context used for the bind operation).

LdapAuthoritiesPopulator

Once the user has been authenticated, this interface is called to obtain the set of granted authorities for the user. The DefaultLdapAuthoritiesPopulator can be configured to obtain user role information from the user's attributes and/or to perform a search for "groups" that the user is a member of and map these to roles.

A custom implementation could obtain the roles from a completely different source, for example from a database.

Configuration

A simple configuration might be as follows: 
   <bean id="contextSource"
       class="org.springframework.security.ldap.DefaultSpringSecurityContextSource">
     <constructor-arg value="ldap://monkeymachine:389/dc=springframework,dc=org"/>
     <property name="userDn" value="cn=manager,dc=springframework,dc=org"/>
     <property name="password" value="password"/>
   </bean>

   <bean id="ldapAuthProvider"
       class="org.springframework.security.ldap.authentication.LdapAuthenticationProvider">
     <constructor-arg>
       <bean class="org.springframework.security.ldap.authentication.BindAuthenticator">
           <constructor-arg ref="contextSource"/>
           <property name="userDnPatterns"><list><value>uid={0},ou=people</value></list></property>
       </bean>
     </constructor-arg>
     <constructor-arg>
       <bean class="org.springframework.security.ldap.userdetails.DefaultLdapAuthoritiesPopulator">
           <constructor-arg ref="contextSource"/>
           <constructor-arg value="ou=groups"/>
           <property name="groupRoleAttribute" value="ou"/>
       </bean>
     </constructor-arg>
   </bean>

This would set up the provider to access an LDAP server with URL ldap://monkeymachine:389/dc=springframework,dc=org. Authentication will be performed by attempting to bind with the DN uid=<user-login-name>,ou=people,dc=springframework,dc=org. After successful authentication, roles will be assigned to the user by searching under the DN ou=groups,dc=springframework,dc=org with the default filter (member=<user's-DN>). The role name will be taken from the "ou" attribute of each match.

The authenticate method will reject empty passwords outright. LDAP servers may allow an anonymous bind operation with an empty password, even if a DN is supplied. In practice this means that if the LDAP directory is configured to allow unauthenticated access, it might be possible to authenticate as any user just by supplying an empty password. More information on the misuse of unauthenticated access can be found in draft -ietf-ldapbis-authmeth-19.txt.

See Also:

  • Constructor Details

    • LdapAuthenticationProvider

      public LdapAuthenticationProvider(LdapAuthenticator authenticator, LdapAuthoritiesPopulator authoritiesPopulator)
      Create an instance with the supplied authenticator and authorities populator implementations.
      Parameters:
      authenticator - the authentication strategy (bind, password comparison, etc) to be used by this provider for authenticating users.
      authoritiesPopulator - the strategy for obtaining the authorities for a given user after they've been authenticated.

    • LdapAuthenticationProvider

      public LdapAuthenticationProvider(LdapAuthenticator authenticator)
      Creates an instance with the supplied authenticator and a null authorities populator. In this case, the authorities must be mapped from the user context.
      Parameters:
      authenticator - the authenticator strategy.

  • Method Details