<?php

class LdapLogin {

  static function checkPassword($username, $password)
  {
    $ldap = ldap_connect("ldap.server.com");
    if ($ldap) {
      $username = 'xxx'; //User to bind
      $password = "xxx"; //Pass

      //EL DN depende de tu arbol LDAP
      $bind_results = @ldap_bind($ldap,"CN=$username,OU=Users,DC=server,DC=com"
            , $password);

      if (!$bind_results) {
        throw new Exception('Can\'t bind to LDAP server');
      }

      $dn = "OU=Users,dc=server,dc=com";
      $filter = "(|(sAMAccountName=" . $user_name . "*))";
      $results = ldap_search($ldap, $dn, $filter);
      $info = ldap_get_entries($ldap, $results);

      if (count($info) > 0) {
        $cn = $info[0]['dn']; //El DN del usuario
        //Si bindea el usuario/pass es válido
        if (@ldap_bind($ldap, $cn , $user_password)){
          ldap_close($ldap);
          return true;
        } else {
          ldap_close($ldap);
          return false;
        }
      }
      ldap_close($ldap);
      return false;
    } else {
      throw new Exception('Can\'t connect to LDAP server');
    }
  }