Recovery of jump table case statements from binary code

Abstract

One of the fundamental problems with the static analysis of binary (executable) code is that of recognizing, in a machine-independent way, the target addresses of n-conditional branches implemented via a jump table. Without these addresses, the decoding of the machine instructions for a given procedure is incomplete, leading to imprecise analysis of the code. In this paper we present a technique for recovering jump tables and their target addresses in a machine and compiler independent way. The technique is based on slicing and copy propagation. The assembly code of a procedure that contains an indexed jump is transformed into a normal form which allows us to determine where the jump table is located and what information it contains (e.g. offsets from the table or absolute addresses). The presented technique has been implemented and tested on SPARC and Pentium code generated by C, C++ , Fortran and Pascal compilers. Our tests show that up to 89% more of the code in a text segment can be found by using this technique, when compared against the standard method of decoding. The technique was developed as part of our retargetable binary translation framework UQBT; however, it is also suitable for other binary-manipulation and analysis tools such as binary profilers, instrumentors and decompilers.