Change Password [CakePHP]

  public function change_pass()
    {
      $this->layout = 'base_layout';
      if ($this->request->is('post','put'))
      {
          $old_pass = $this->request->data['User']['old_password'];
          $new_pass = $this->request->data['User']['new_password'];
          $con_pass = $this->request->data['User']['confirm_password'];

          if($con_pass == $new_pass)
          {


          //    pr($this->request->data);
            $params =
              array(
                'conditions' => array(
                      'username' => $_SESSION['username'],
                      'password' => $old_pass//$this->request->data['User']['old_password']
                )
              );
            $result = $this->User->find('all', $params);
              if($result != null)
              {
                  $this->User->id = $result[0]['User']['id'];

                  $this->User->set(array('password'=>$new_pass));

                    if($this->User->save())
                    {
                        $this->Flash->success(__('Success! Password successfully changed! '));
                    }
                    else {
                      # code...
                      $this->Flash->error(
                          __('Oops! Something went wrong!')
                      );
                    }

              }
              else {
                $this->Flash->error(
                    __('Oops! Sorry your current password is invalid!')
                );
              }
          }
          else {
            $this->Flash->error(
                __('Oops! Sorry your Passwords are not matched!')
            );
          }
      }
    }