class ActionDispatch::HostAuthorization::Permissions

def allows?(host)
  @hosts.any? do |allowed|
    if allowed.is_a?(IPAddr)
      begin
        allowed === extract_hostname(host)
      rescue
        # IPAddr#=== raises an error if you give it a hostname instead of
        # IP. Treat similar errors as blocked access.
        false
      end
    else
      allowed === host
    end
  end
end