Configuring LDAP on Spring Boot 3

Question

I was experimenting with spring boot 3 and spring security 6.

I configured my spring security to use LDAP authentication via AD, which works fine, but spring boot still doesn't detect a custom 'AuthenticationManager' and generates its own password.

This is how I set up my LDAP authentication:

@Autowired
public void configure(AuthenticationManagerBuilder auth) throws Exception {
    auth.ldapAuthentication().userSearchBase(userSearchBase).userSearchFilter(userSearchFilter).contextSource()
            .url(url).managerDn(managerDn).managerPassword(ldapPassword);
}

Even after configuring ldap, this is what I get.

Answer 1

First, you must create a context source, which includes your LDAP url (url), your Manager DN or the Base DN from which your users belong (managerDn), your LDAP password to authenticate yourself / your app to the server, and, last but not least, the connection pooling flag for LDAP (setPooled), which is recommended if you have a large number of users.

@Bean
public LdapContextSource contextSource() {
    LdapContextSource contextSource = new LdapContextSource();
    contextSource.setUrl(url);
    contextSource.setUserDn(managerDn);
    contextSource.setPassword(ldapPassword);
    contextSource.setPooled(true);

    return contextSource;
}

Second, you must configure the authentication manager object, which will assist spring boot in recognising that you will be using LDAP for authentication.

@Bean
AuthenticationManager authenticationManager(BaseLdapPathContextSource contextSource) {
    LdapBindAuthenticationManagerFactory factory = new LdapBindAuthenticationManagerFactory(contextSource);
    factory.setUserSearchBase(userSearchBase);
    factory.setUserSearchFilter(userSearchFilter);

    return factory.createAuthenticationManager();
}

Finally, this is entirely optional. If you need to look up an LDAP user in your app, this interface will come in handy.

@Bean
public LdapTemplate ldapTemplate() {
    return new LdapTemplate(contextSource());
}