The functional correctness of compiler optimization does not ensure the security properties of the source program. A functionally correct compiler optimization may introduce new security vulnerabilities in the optimized program. In a compiler, ensuring the security of every optimization is a challenging task as it applies hundreds of optimizations. Thus, this work aims to develop a translation validation (TV) of information leakage for the optimization phase of the compiler without considering any intermediate information from the compiler. Our method measures the information leakage in a path, uses a concept of leak propagation over paths and loops, and defines the relative security between the source and optimized programs. This work considers two attack models based on different observation points to access the local memory and proposes different TV approaches. The correctness and complexity of the TV method are also provided. The experimental results in the SPARK compiler on various benchmarks show that the optimized program is not relatively secure in many cases.

Compiler optimizations can be functionally correct but not secure. In this work, we attempt to quantify the information leakage in a program for the security verification of compiler optimizations. Our work has the following contributions. We demonstrate that static taint analysis is applicable for security verification of compile optimizations. We develop a completely automated approach for quantifying the information leak in a program in the context of compiler optimizations. Our method avoids many false-positives scenarios due to implicit flow. It can handle leaks in a loop and propagates leaks over paths using the leak propagation vector. With our quantification parameters, we verify the relative security of source and transformed programs considering the optimizations phase of a compiler as a black box. Our experimental evaluations on benchmarks for various compiler optimizations in SPARK show that the SPARK compiler is actually leaky.