import java.util.ArrayList;
import java.util.List;
import java.util.Properties;

import javax.naming.Context;
import javax.naming.NameNotFoundException;
import javax.naming.NamingEnumeration;
import javax.naming.NamingException;
import javax.naming.directory.SearchControls;
import javax.naming.directory.SearchResult;
import javax.naming.ldap.InitialLdapContext;
import javax.naming.ldap.LdapContext;

import com.juliasoft.julia.extraction.EntryPoint;

public class LdapPoisoning {

  public @EntryPoint List<Object> search(int controls, String[] attributes, String base, String filter, String[] args)
                                      throws NamingException {
    LdapContext ctx = null;
    List<Object> result = new ArrayList<>();

    try {
      Properties env = createEnvironment();    
      ctx = new InitialLdapContext(env, null); // LDAP Authentication Disabled (Java) warning issued here 


      SearchControls ctls = new SearchControls();
      ctls.setSearchScope(controls);
      ctls.setReturningAttributes(attributes);
      ctls.setReturningObjFlag(true);          // Potential LDAP Poisoning (Java) warning issued here 

      NamingEnumeration<SearchResult> enm = ctx.search(base, filter, args, ctls);
      while (enm.hasMoreElements()) {
        SearchResult sr = enm.nextElement();
        result.add(sr.getObject());                /* Previous setReturningObjFlag(true) means that modifications 
                                                    * to the object returned by sr.getObject() can be reflected into the database.
                                                    */
      }
    }
    catch (NamingException ne) {
      throw ne;
    }
    finally {
      if (ctx != null)
        ctx.close();
    }

    return result;                                 /* 'result' list returned by search() contains   
                                                    * an object whose modifications can be reflected into the database.
                                                    */
  }

  public boolean exists(String dn) throws NamingException {
    Properties env = createEnvironment();
    LdapContext ctx = new InitialLdapContext(env, null);
    SearchControls ctls = new SearchControls();
    ctls.setSearchScope(SearchControls.OBJECT_SCOPE);
    ctls.setReturningAttributes(new String[0]);
    ctls.setReturningObjFlag(false);                            // ok: flag set to false 

    try {
      ctx.search(dn, "(objectClass=*)", ctls);
      return true;
    }
    catch (NameNotFoundException nne) {
      return false;
    }
  }

  protected Properties createEnvironment() {
    Properties env = new Properties();
    env.setProperty(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.ldap.LdapCtxFactory");
    env.setProperty(Context.PROVIDER_URL, "www.juliasoft.com");
    env.setProperty(Context.OBJECT_FACTORIES, "my.factory");
    env.setProperty(Context.SECURITY_PRINCIPAL, "user");
    env.setProperty(Context.SECURITY_CREDENTIALS, "verysecretpassword");
    env.setProperty(Context.SECURITY_AUTHENTICATION, "none"); // Disables authentication, leading to the "LDAP Authentication Disabled (Java)" warning above. 
    return env;
  }
}