LdapAuthenticationProvider

Class Overview

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.

Summary

[Expand] Inherited Fields
From class org.springframework.security.ldap.authentication.AbstractLdapAuthenticationProvider protected final Log logger protected MessageSourceAccessor messages protected UserDetailsContextMapper userDetailsContextMapper

Public Constructors
	LdapAuthenticationProvider(LdapAuthenticator authenticator, LdapAuthoritiesPopulator authoritiesPopulator) Create an instance with the supplied authenticator and authorities populator implementations.
	LdapAuthenticationProvider(LdapAuthenticator authenticator) Creates an instance with the supplied authenticator and a null authorities populator.

Public Methods
void	setHideUserNotFoundExceptions(boolean hideUserNotFoundExceptions)

Protected Methods
DirContextOperations	doAuthentication(UsernamePasswordAuthenticationToken authentication)
LdapAuthoritiesPopulator	getAuthoritiesPopulator()
Collection<? extends GrantedAuthority>	loadUserAuthorities(DirContextOperations userData, String username, String password)

[Expand] Inherited Methods
From class org.springframework.security.ldap.authentication.AbstractLdapAuthenticationProvider Authentication authenticate(Authentication authentication) Performs authentication with the same contract as authenticate(Authentication). Authentication createSuccessfulAuthentication(UsernamePasswordAuthenticationToken authentication, UserDetails user) Creates the final Authentication object which will be returned from the authenticate method. abstract DirContextOperations doAuthentication(UsernamePasswordAuthenticationToken auth) UserDetailsContextMapper getUserDetailsContextMapper() Provides access to the injected UserDetailsContextMapper strategy for use by subclasses. abstract Collection<? extends GrantedAuthority> loadUserAuthorities(DirContextOperations userData, String username, String password) void setAuthoritiesMapper(GrantedAuthoritiesMapper authoritiesMapper) void setMessageSource(MessageSource messageSource) void setUseAuthenticationRequestCredentials(boolean useAuthenticationRequestCredentials) Determines whether the supplied password will be used as the credentials in the successful authentication token. void setUserDetailsContextMapper(UserDetailsContextMapper userDetailsContextMapper) Allows a custom strategy to be used for creating the UserDetails which will be stored as the principal in the Authentication returned by the createSuccessfulAuthentication(org.springframework.security.authentication.UsernamePasswordAuthenticationToken, org.springframework.security.core.userdetails.UserDetails) method. boolean supports(Class<?> authentication) Returns true if this AuthenticationProvider supports the indicated Authentication object.
From class java.lang.Object Object clone() boolean equals(Object arg0) void finalize() final Class<?> getClass() int hashCode() final void notify() final void notifyAll() String toString() final void wait() final void wait(long arg0, int arg1) final void wait(long arg0)
From interface org.springframework.context.MessageSourceAware abstract void setMessageSource(MessageSource arg0)
From interface org.springframework.security.authentication.AuthenticationProvider abstract Authentication authenticate(Authentication authentication) Performs authentication with the same contract as authenticate(Authentication). abstract boolean supports(Class<?> authentication) Returns true if this AuthenticationProvider supports the indicated Authentication object.