Future vehicles will be wirelessly connected to nearby vehicles, to the road infrastructure and to the Internet in order to enable new comfort features, safety functions and a number of new vehicle-specific services. The latter will include a fast, secure, and reliable way to remotely diagnose and reconfigure a vehicle as well as to install new software on the electronic control units integrated in a vehicle. Such wireless software updates are beneficial for both automotive OEMs and customers, as they allow to enable new features of the vehicle remotely and to fix software bugs by installing a new software version over the air. Wireless diagnostics and software updates are required in several stages of a vehicle's lifetime: from the manufacturing stage on the assembly line and the maintenance in a workshop to the remote download of up-to-date software directly by the car owner. To support this process over a whole vehicle's lifetime, a generic framework is needed. In this paper we propose a generic framework enabling secure and efficient wireless automotive SW updates and hence supporting a vehicle's whole lifetime. We describe the IEEE 802.11s network used as wireless medium to interconnect vehicles and diagnostic devices in a reliable, trustworthy and fast way and propose a dedicated cross-layer security concept applying strong authentication as well as encryption mechanisms.