Boundless memory allocations for memory safety and high availability

Spatial memory errors (like buffer overflows) are still a major threat for applications written in C. Most recent work focuses on memory safety - when a memory error is detected at runtime, the application is aborted. Our goal is not only to increase the memory safety of applications but also to increase the application´s availability. Therefore, we need to tolerate spatial memory errors at runtime. We have implemented a compiler extension, Boundless, that automatically adds the tolerance feature to C applications at compile time. We show that this can increase the availability of applications. Our measurements also indicate that Boundless has a lower performance overhead than SoftBound, a state-of-the-art approach to detect spatial memory errors. Our performance gains result from a novel way to represent pointers. Nevertheless, Boundless is compatible with existing C code. Additionally, Boundless provides a trade-off to reduce the runtime overhead even further: We introduce vulnerability specific patching for spatial memory errors to tolerate only known vulnerabilities. Vulnerability specific patching has an even lower runtime overhead than full tolerance.