This paper presents a simple but elegant solution to the now infamous buffer overflow and some primitive format string attacks. Most security exploits have traditionally overwritten a function's saved return address. The attacker can then direct the flow of execution into an arbitrary instruction stream that is invoked when the vulnerable function tries to return control to its caller.
By taking advantages of one of the nuances of Sun Microsystem's Sparc processor architecture, we were able to engineer a kernel modification to OpenBSD 2.8 to help safeguard the return address. The kernel modification performs transparent, automatic and atomic operations on the return address before it is written to the stack and before the function transfers execution back to the saved return address.
Knowledge of what buffer overflows are , their relevance to security exploits [1,13] and why they occur is a prerequisite to understanding this paper.
Section 2 describes the architectural issues involved in StackGhost. Section 3 details the implementation. Section 4 describes the performance effects. Section 5 acknowledges the limitations. Section 6 hypothesizes on extesion to other architectures. Section 7 describes the related research. Finally, Section 8 presents our conclusions.