LDAP Authentication using Java

Question

I need to do LDAP Authentication for an application.

I tried the following program:

import java.util.Hashtable;  

import javax.naming.Context;  
import javax.naming.NamingException;  
import javax.naming.ldap.InitialLdapContext;  
import javax.naming.ldap.LdapContext;  


public class LdapContextCreation {  
    public static void main(String[] args) {  
        LdapContextCreation ldapContxCrtn = new LdapContextCreation();  
        LdapContext ctx = ldapContxCrtn.getLdapContext();  
    }  
    public LdapContext getLdapContext(){  
        LdapContext ctx = null;  
        try{  
            Hashtable env = new Hashtable();  
            env.put(Context.INITIAL_CONTEXT_FACTORY,  "com.sun.jndi.ldap.LdapCtxFactory");  
            env.put(Context.SECURITY_AUTHENTICATION, "Simple");  
            //it can be <domain\\userid> something that you use for windows login  
            //it can also be  
            env.put(Context.SECURITY_PRINCIPAL, "[email protected]");  
            env.put(Context.SECURITY_CREDENTIALS, "password");  
            //in following property we specify ldap protocol and connection url.  
            //generally the port is 389  
            env.put(Context.PROVIDER_URL, "ldap://server.domain.com");  
            ctx = new InitialLdapContext(env, null);  
            System.out.println("Connection Successful.");  
        }catch(NamingException nex){  
            System.out.println("LDAP Connection: FAILED");  
            nex.printStackTrace();  
        }  
        return ctx;  
    }  

}

Getting following exception:

LDAP Connection: FAILED
javax.naming.AuthenticationException: [LDAP: error code 49 - Invalid Credentials]
    at com.sun.jndi.ldap.LdapCtx.mapErrorCode(LdapCtx.java:3053)
    at com.sun.jndi.ldap.LdapCtx.processReturnCode(LdapCtx.java:2999)
    at com.sun.jndi.ldap.LdapCtx.processReturnCode(LdapCtx.java:2801)
    at com.sun.jndi.ldap.LdapCtx.connect(LdapCtx.java:2715)
    at com.sun.jndi.ldap.LdapCtx.(LdapCtx.java:305)
    at com.sun.jndi.ldap.LdapCtxFactory.getUsingURL(LdapCtxFactory.java:187)
    at com.sun.jndi.ldap.LdapCtxFactory.getUsingURLs(LdapCtxFactory.java:205)
    at com.sun.jndi.ldap.LdapCtxFactory.getLdapCtxInstance(LdapCtxFactory.java:148)
    at com.sun.jndi.ldap.LdapCtxFactory.getInitialContext(LdapCtxFactory.java:78)
    at javax.naming.spi.NamingManager.getInitialContext(NamingManager.java:235)
    at javax.naming.InitialContext.initializeDefaultInitCtx(InitialContext.java:318)
    at javax.naming.InitialContext.getDefaultInitCtx(InitialContext.java:348)
    at javax.naming.InitialContext.internalInit(InitialContext.java:286)
    at javax.naming.InitialContext.init(InitialContext.java:308)
    at javax.naming.ldap.InitialLdapContext.(InitialLdapContext.java:99)
    at LdapContextCreation.getLdapContext(LdapContextCreation.java:27)
    at LdapContextCreation.main(LdapContextCreation.java:12)

Few more points to consider:

1. Earlier I was using tomcat 5.3.5 but somebody told me that only tomcat 6 supports it so I downloaded tomcat 6.0.35 and currently using this version only.

2. Configured server.xml and added the following code -

   <Realm className="org.apache.catalina.realm.JNDIRealm" 
                      debug="99" 
                      connectionURL="ldap://server.domain.com:389/"  
                      userPattern="{0}" />
   

3. Commented the following code from server.xml -

   <!-- Commenting for LDAP
     <Realm className="org.apache.catalina.realm.UserDatabaseRealm"
        resourceName="UserDatabase"/> -->
   

4. Steps 2 and 3 from article

5. Someone suggested that there are some jar files that are supposed to be copied to tomcat in order to run ldap authentication, is that something I need to do? And which jar files?

6. Also, I am using the correct credentials for sure, then what is causing this issue?

7. Is there a way I can figure out the correct attributes for LDAP in case I am using incorrect ones?

Answer 1

Following Code authenticates from LDAP using pure Java JNDI. The Principle is:-

1. First Lookup the user using a admin or DN user.
2. The user object needs to be passed to LDAP again with the user credential
3. No Exception means - Authenticated Successfully. Else Authentication Failed.

Code Snippet

public static boolean authenticateJndi(String username, String password) throws Exception{
    Properties props = new Properties();
    props.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.ldap.LdapCtxFactory");
    props.put(Context.PROVIDER_URL, "ldap://LDAPSERVER:PORT");
    props.put(Context.SECURITY_PRINCIPAL, "uid=adminuser,ou=special users,o=xx.com");//adminuser - User with special priviledge, dn user
    props.put(Context.SECURITY_CREDENTIALS, "adminpassword");//dn user password


    InitialDirContext context = new InitialDirContext(props);

    SearchControls ctrls = new SearchControls();
    ctrls.setReturningAttributes(new String[] { "givenName", "sn","memberOf" });
    ctrls.setSearchScope(SearchControls.SUBTREE_SCOPE);

    NamingEnumeration<javax.naming.directory.SearchResult> answers = context.search("o=xx.com", "(uid=" + username + ")", ctrls);
    javax.naming.directory.SearchResult result = answers.nextElement();

    String user = result.getNameInNamespace();

    try {
        props = new Properties();
        props.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.ldap.LdapCtxFactory");
        props.put(Context.PROVIDER_URL, "ldap://LDAPSERVER:PORT");
        props.put(Context.SECURITY_PRINCIPAL, user);
        props.put(Context.SECURITY_CREDENTIALS, password);

   context = new InitialDirContext(props);
    } catch (Exception e) {
        return false;
    }
    return true;
}