Implicit signature checking

Abstract

Proposes a control flow checking method that assigns unique initial signatures to each basic block in a program by using the block's start address. Using this strategy, implicit signature checking points are obtained at the beginning of each basic block, which results in a short error detection latency (2-5 instructions). Justifying signatures are embedded at each branch instruction, and a watchdog timer is used to detect the absence of a signature checking point. The method does not require the building of a program flow graph and it handles jumps to destinations that are not fixed at compile/link-time, e.g. subroutine calls using function pointers in the C language. This paper includes a generalized description of the control flow checking method, as well as a description and evaluation of an implementation of the method.<>