Checking Memory Safety with Abstract Interpretation and Deductive Verification

We propose an original approach for checking memory safety of C pointer programs, by combining deductive verification and abstract interpretation techniques. The approach is modular and contextual, thanks to the use of Hoare-style annotations (preand postconditions), allowing us to verify each C function independently. Deductive verification is used to check these annotations in a sound way. Abstract interpretation techniques are used to automatically generate such annotations, in an idiomatic way: standard practice of C programming is identified and incorporated as heuristics. Our first contribution is the design of an abstract domain for implications, which makes it possible to build efficient contextual analyses. Our second contribution is an efficient back-and-forth propagation method to generate contextual annotations in a modular way, in the framework of abstract interpretation. We implemented our method in Caduceus, a tool for the verification of C programs, and successfully generated appropriate annotations for the C standard string library functions.