friendica/src/BaseModule.php

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<?php
namespace Friendica;
use Friendica\Core\L10n;
use Friendica\Core\System;
/**
* All modules in Friendica should extend BaseModule, although not all modules
* need to extend all the methods described here
*
* The filename of the module in src/Module needs to match the class name
* exactly to make the module available.
*
* @author Hypolite Petovan <hypolite@mrpetovan.com>
*/
abstract class BaseModule extends BaseObject
{
/**
* @brief Initialization method common to both content() and post()
*
* Extend this method if you need to do any shared processing before both
* content() or post()
*/
public static function init()
{
}
/**
* @brief Module GET method to display raw content from technical endpoints
*
* Extend this method if the module is supposed to return communication data,
* e.g. from protocol implementations.
*/
public static function rawContent()
{
}
/**
* @brief Module GET method to display any content
*
* Extend this method if the module is supposed to return any display
* through a GET request. It can be an HTML page through templating or a
* XML feed or a JSON output.
*
* @return string
*/
public static function content()
{
$o = '';
return $o;
}
/**
* @brief Module POST method to process submitted data
*
* Extend this method if the module is supposed to process POST requests.
* Doesn't display any content
*/
public static function post()
{
// goaway('module');
}
/**
* @brief Called after post()
*
* Unknown purpose
*/
public static function afterpost()
{
}
/*
* Functions used to protect against Cross-Site Request Forgery
* The security token has to base on at least one value that an attacker can't know - here it's the session ID and the private key.
* In this implementation, a security token is reusable (if the user submits a form, goes back and resubmits the form, maybe with small changes;
* or if the security token is used for ajax-calls that happen several times), but only valid for a certain amout of time (3hours).
* The "typename" seperates the security tokens of different types of forms. This could be relevant in the following case:
* A security token is used to protekt a link from CSRF (e.g. the "delete this profile"-link).
* If the new page contains by any chance external elements, then the used security token is exposed by the referrer.
* Actually, important actions should not be triggered by Links / GET-Requests at all, but somethimes they still are,
* so this mechanism brings in some damage control (the attacker would be able to forge a request to a form of this type, but not to forms of other types).
*/
public static function getFormSecurityToken($typename = '')
{
$a = get_app();
$timestamp = time();
$sec_hash = hash('whirlpool', $a->user['guid'] . $a->user['prvkey'] . session_id() . $timestamp . $typename);
return $timestamp . '.' . $sec_hash;
}
public static function checkFormSecurityToken($typename = '', $formname = 'form_security_token')
{
$hash = null;
if (!empty($_REQUEST[$formname])) {
/// @TODO Careful, not secured!
$hash = $_REQUEST[$formname];
}
if (!empty($_SERVER['HTTP_X_CSRF_TOKEN'])) {
/// @TODO Careful, not secured!
$hash = $_SERVER['HTTP_X_CSRF_TOKEN'];
}
if (empty($hash)) {
return false;
}
$max_livetime = 10800; // 3 hours
$a = get_app();
$x = explode('.', $hash);
if (time() > (IntVal($x[0]) + $max_livetime)) {
return false;
}
$sec_hash = hash('whirlpool', $a->user['guid'] . $a->user['prvkey'] . session_id() . $x[0] . $typename);
return ($sec_hash == $x[1]);
}
public static function getFormSecurityStandardErrorMessage()
{
return L10n::t("The form security token was not correct. This probably happened because the form has been opened for too long \x28>3 hours\x29 before submitting it.") . EOL;
}
public static function checkFormSecurityTokenRedirectOnError($err_redirect, $typename = '', $formname = 'form_security_token')
{
if (!self::checkFormSecurityToken($typename, $formname)) {
$a = get_app();
logger('check_form_security_token failed: user ' . $a->user['guid'] . ' - form element ' . $typename);
logger('check_form_security_token failed: _REQUEST data: ' . print_r($_REQUEST, true), LOGGER_DATA);
notice(check_form_security_std_err_msg());
goaway(System::baseUrl() . $err_redirect);
}
}
public static function checkFormSecurityTokenForbiddenOnError($typename = '', $formname = 'form_security_token')
{
if (!self::checkFormSecurityToken($typename, $formname)) {
$a = get_app();
logger('check_form_security_token failed: user ' . $a->user['guid'] . ' - form element ' . $typename);
logger('check_form_security_token failed: _REQUEST data: ' . print_r($_REQUEST, true), LOGGER_DATA);
header('HTTP/1.1 403 Forbidden');
killme();
}
}
}