Code-reuse attacks are software exploits in which an attacker directs control flow through existing code with a malicious result. One such technique, return-oriented programming, is based on "gadgets" (short pre-existing sequences of code ending in a ret instruction) being executed in arbitrary order as a result of a stack corruption exploit. Many existing codereuse defenses have relied upon a particular attribute of the attack in question (e.g., the frequency of ret instructions in a return-oriented attack), which leads to an incomplete protection, while a smaller number of efforts in protecting all exploitable control flow transfers suffer from limited deployability due to high performance overhead. In this paper, we present a novel cost-effective defense technique called control flow locking, which allows for effective enforcement of control flow integrity with a small performance overhead. Specifically, instead of immediately determining whether a control flow violation happens before the control flow transfer takes place, control flow locking lazily detects the violation after the transfer. To still restrict attackers' capability, our scheme guarantees that the deviation of the normal control flow graph will only occur at most once. Further, our scheme ensures that this deviation cannot be used to craft a malicious system call, which denies any potential gains an attacker might obtain from what is permitted in the threat model. We have developed a proof-of-concept prototype in Linux and our evaluation demonstrates desirable effectiveness and competitive performance overhead with existing techniques. In several benchmarks, our scheme is able to achieve significant gains.

Return-oriented programming is an effective code-reuse attack in which short code sequences ending in a ret instruction are found within existing binaries and executed in arbitrary order by taking control of the stack. This allows for Turing-complete behavior in the target program without the need for injecting attack code, thus significantly negating current code injection defense efforts (e.g., W⊕X). On the other hand, its inherent characteristics, such as the reliance on the stack and the consecutive execution of returnoriented gadgets, have prompted a variety of defenses to detect or prevent it from happening.In this paper, we introduce a new class of code-reuse attack, called jump-oriented programming. This new attack eliminates the reliance on the stack and ret instructions (including ret-like instructions such as pop+jmp) seen in return-oriented programming without sacrificing expressive power. This attack still builds and chains functional gadgets, each performing certain primitive operations, except these gadgets end in an indirect branch rather than ret. Without the convenience of using ret to unify them, the attack relies on a dispatcher gadget to dispatch and execute the functional gadgets. We have successfully identified the availability of these jump-oriented gadgets in the GNU libc library. Our experience with an example shellcode attack demonstrates the practicality and effectiveness of this technique.