NetReach: Guaranteed Network Availability and Reachability to enable Resilient Networks for Embedded Systems

Networked embedded devices are increasingly deployed in safety critical environments such as robotics, smart manufacturing and autonomous vehicles. Availability is an essential prerequisite of safety critical systems, which depend upon timely access to sensed data to inform the real-time control of actuators. Recent work has demonstrated that trusted computing features can be used to guarantee the availability of local resources to the safety-critical applications. However, prior work fails to guarantee the availability of a network connection, which is essential for correct system operation. To address this issue, we contribute NetReach, which uses Arm TrustZone to guarantee network availability to, and the reachability of, critical applications via a secure backup channel. Evaluation of NetReach shows that it can preserve the network connectivity of critical applications while under attack, with a worst case overhead of 18.66 % for networked software running in the Normal World. Furthermore, NetReach introduces minimal additional code in the Secure World (only 418 lines of code). The presented features of NetReach enable future work toward resilient networks.