Adding some password validation rules. refs #1256

@@ -22,6 +22,8 @@ const ACTION_ACTIVATE = 'wpmu_activate_user';
 
 const OPTION_NAME = 'tz_auth'; // Database lookup key (`wp_options`.`option_name`)
 
+const PASS_MAX_LEN = 15; // Maximum length of password
+
     call_user_func(function() {
         global $wpdb;
         if (empty($wpdb->signups)) {
@@ -263,8 +265,12 @@ class Validation extends Common\Validation {
             throw new Exception('<li>Password can not be blank</li>');
         }
 
-        if (false !== strpos($val, ' ')) {
-            throw new Exception('<li>Password can not contain spaces</li>');
+        if (isset($val[PASS_MAX_LEN + 1])) {
+            throw new Exception('<li>Password can not be longer than ' . PASS_MAX_LEN . ' characters.</li>');
+        }
+
+        if (preg_match('/(\\\\|\\\'|"| )+/i', $val)) {
+            throw new Exception('<li>Password can not contain spaces, backslashes (\) or quotes</li>');
         }
     }