- Narrow the set of allowed usernames to prevent people from messing with it.

modules/user.module

@@ -174,9 +174,8 @@ function user_validate_name($name) {
   if (ereg("^ ", $name)) return t("The username cannot begin with a space.");
   if (ereg(" \$", $name)) return t("The username cannot end with a space.");
   if (ereg("  ", $name)) return t("The username cannot contain multiple spaces in a row.");
-  // if (ereg("[^a-zA-Z0-9@-@]", $name)) return t("The username contains an illegal character.");
+  if (ereg("[^ a-zA-Z0-9@-@]", $name)) return t("The username contains an illegal character.");
   if (ereg('@', $name) && !eregi('@([0-9a-z](-?[0-9a-z])*\.)+[a-z]{2}([zmuvtg]|fo|me)?$', $name)) return t("The username is not a valid authentication ID.");
-  if (!eregi('^[[:print:]]+', $name)) return t("The name contains an illegal character.");
   if (strlen($name) > 56) return t("The username '$name' is too long: it must be less than 56 characters.");
 }