filter($new_var,[more options]) * and then using $secure->clean['var'] as a filtered equivalent, although * this is *not* mandatory at all. * * @author Yannick Warnier */ class Security{ var $clean = array(); /** * Checks if the absolute path given is really under the checker path * @param string Absolute path to be checked (with trailing slash) * @param string Checker path under which the path should be (with trailing slash) * @return bool True if the path is under the checker, false otherwise */ function check_abs_path($abs_path,$checker_path) { if(empty($checker_path)){return false;} //checker path must be set $true_path=str_replace("\\", "/", realpath($abs_path)); $found = strpos($true_path.'/',$checker_path); if($found===0) { return true; } return false; } /** * Checks if the relative path given is really under the checker path * @param string Relative path to be checked (relative to the current directory) (with trailing slash) * @param string Checker path under which the path should be (with trailing slash) * @return bool True if the path is under the checker, false otherwise */ function check_rel_path($rel_path,$checker_path) { if(empty($checker_path)){return false;} //checker path must be set $current_path = getcwd(); //no trailing slash if(substr($rel_path,-1,1)!='/'){ $rel_path = '/'.$rel_path; } $abs_path = $current_path.$rel_path; $true_path=str_replace("\\", "/", realpath($abs_path)); $found = strpos($true_path.'/',$checker_path); if($found===0) { return true; } return false; } /** * This function checks that the token generated in get_token() has been kept (prevents * Cross-Site Request Forgeries attacks) * @param string The array in which to get the token ('get' or 'post') * @return bool True if it's the right token, false otherwise */ function check_token($array='post') { switch($array){ case 'get': if(isset($_SESSION['sec_token']) && isset($_GET['sec_token']) && $_SESSION['sec_token'] === $_GET['sec_token']) { return true; } return false; case 'post': if(isset($_SESSION['sec_token']) && isset($_POST['sec_token']) && $_SESSION['sec_token'] === $_POST['sec_token']) { return true; } return false; default: if(isset($_SESSION['sec_token']) && isset($array) && $_SESSION['sec_token'] === $array) { return true; } return false; } return false; //just in case, don't let anything slip } /** * Checks the user agent of the client as recorder by get_ua() to prevent * most session hijacking attacks. * @return bool True if the user agent is the same, false otherwise */ function check_ua() { if(isset($_SESSION['sec_ua']) and $_SESSION['sec_ua'] === $_SERVER['HTTP_USER_AGENT'].$_SESSION['sec_ua_seed']) { return true; } return false; } /** * Clear the security token from the session * @return void */ function clear_token() { $_SESSION['sec_token'] = null; unset($_SESSION['sec_token']); } /** * This function sets a random token to be included in a form as a hidden field * and saves it into the user's session. Returns an HTML form element * This later prevents Cross-Site Request Forgeries by checking that the user is really * the one that sent this form in knowingly (this form hasn't been generated from * another website visited by the user at the same time). * Check the token with check_token() * @return string Hidden-type input ready to insert into a form */ function get_HTML_token() { $token = md5(uniqid(rand(),TRUE)); $string = ''; $_SESSION['sec_token'] = $token; return $string; } /** * This function sets a random token to be included in a form as a hidden field * and saves it into the user's session. * This later prevents Cross-Site Request Forgeries by checking that the user is really * the one that sent this form in knowingly (this form hasn't been generated from * another website visited by the user at the same time). * Check the token with check_token() * @return string Token */ function get_token() { $token = md5(uniqid(rand(),TRUE)); $_SESSION['sec_token'] = $token; return $token; } /** * Gets the user agent in the session to later check it with check_ua() to prevent * most cases of session hijacking. * @return void */ function get_ua() { $_SESSION['sec_ua_seed'] = uniqid(rand(),TRUE); $_SESSION['sec_ua'] = $_SERVER['HTTTP_USER_AGENT'].$_SESSION['sec_ua_seed']; } /** * This function filters a variable to the type given, with the options given * @param mixed The variable to be filtered * @param string The type of variable we expect (bool,int,float,string) * @param array Additional options * @return bool True if variable was filtered and added to the current object, false otherwise */ function filter($var,$type='string',$options=array()) { //This function is not finished! Do not use! $result = false; //get variable name and value $args = func_get_args(); $names =array_keys($args); $name = $names[0]; $value = $args[$name]; switch($type){ case 'bool': $result = (bool) $var; break; case 'int': $result = (int) $var; break; case 'float': $result = (float) $var; break; case 'string': break; case 'array': //an array variable shouldn't be given to the filter return false; default: return false; } if(!empty($option['save'])){ $this->clean[$name]=$result; } return $result; } /** * This function returns a variable from the clean array. If the variable doesn't exist, * it returns null * @param string Variable name * @return mixed Variable or NULL on error */ function get($varname) { if(isset($this->clean[$varname])){ return $this->clean[$varname]; } return NULL; } /** * This function tackles the XSS injections. * * Filtering for XSS is very easily done by using the htmlentities() function. * This kind of filtering prevents JavaScript snippets to be understood as such. * @param string The variable to filter for XSS * @return string Filtered string */ function remove_XSS($var) { global $charset; return htmlentities($var,ENT_QUOTES,$charset); } } ?>