Abstract

Certified software consists of a machine executable program plus a machine checkable proof showing that the software is free of bugs with respect to a particular specification. Constructing certified system software is an important step toward building a reliable and secure computing platform for future critical applications. In addition to the benefits from provably safe components, architectures of certified systems may also be simplified to achieve better efficiency. However, because system software consists of program modules that use many different computation features and span different abstraction levels, it is difficult to design a single type system or program logic to certify the whole system. As a result, significant amount of kernel code of today’s operating systems has to be implemented in unsafe languages, despite recent progress on type-safe languages. In this thesis, I develop a new methodology to solve this problem, which applies different verification systems to certify different program modules, and then links the certified modules in an open framework to compose the whole certified software package. Specifically, this thesis makes contributions in the following two aspects. First, I develop new Hoare-style program logics to certify low-level programs with

Citations