Struts: Incomplete validate() Method Definition

Description

If the code does not call super.validate(), the Validation Framework cannot check the contents of the form against a validation form. In other words, the validation framework will be disabled for the given form.

Background

The Struts Validator uses a form's validate() method to check the contents of the form properties against the constraints specified in the associated validation form. That means the following classes have a validate() method that is part of the validation framework: ValidatorForm, ValidatorActionForm, DynaValidatorForm, and DynaValidatorActionForm. If the code creates a class that extends one of these classes, and if that class implements custom validation logic by overriding the validate() method, the code must call super.validate() in the validate() implementation.

Demonstrations

The following examples help to illustrate the nature of this weakness and describe methods or techniques which can be used to mitigate the risk.

Note that the examples here are by no means exhaustive and any given weakness may have many subtle varieties, each of which may require different detection methods or runtime controls.

Example One

In the following Java example the class RegistrationForm is a Struts framework ActionForm Bean that will maintain user input data from a registration webpage for an online business site. The user will enter registration data and the RegistrationForm bean in the Struts framework will maintain the user data. Tthe RegistrationForm class implements the validate method to validate the user input entered into the form.

public class RegistrationForm extends org.apache.struts.validator.ValidatorForm {

  // private variables for registration form
  private String name;
  private String email;
  ...

  public RegistrationForm() {
    super();
  }

  public ActionErrors validate(ActionMapping mapping, HttpServletRequest request) {
    ActionErrors errors = new ActionErrors();
    if (getName() == null || getName().length() < 1) {
      errors.add("name", new ActionMessage("error.name.required"));
    }
    return errors;
  }


  // getter and setter methods for private variables
  ...

}

Although the validate method is implemented in this example the method does not call the validate method of the ValidatorForm parent class with a call super.validate(). Without the call to the parent validator class only the custom validation will be performed and the default validation will not be performed. The following example shows that the validate method of the ValidatorForm class is called within the implementation of the validate method.

public class RegistrationForm extends org.apache.struts.validator.ValidatorForm {


  // private variables for registration form
  private String name;
  private String email;
  ...

  public RegistrationForm() {
    super();
  }

  public ActionErrors validate(ActionMapping mapping, HttpServletRequest request) {
    ActionErrors errors = super.validate(mapping, request);
    if (errors == null) {
      errors = new ActionErrors();
    }


  if (getName() == null || getName().length() < 1) {
    errors.add("name", new ActionMessage("error.name.required"));
  }
  return errors;

}

  // getter and setter methods for private variables
  ...
}

See Also