public static final boolean isValidLabel(byte[] label) {
    for (int i = 0; i < label.length; i++) {
      if (!isValidAuthChar(label[i])) {
        return false;
      }
    }
    return true;
  }
A simple validator that validates the labels passed
hbase-client/src/main/java/org/apache/hadoop/hbase/security/visibility/VisibilityLabelsValidator.java