EHCtor: Detecting Resource-Release Omission Faults in Error-Handling Code for Systems Software

Adequate error-handling code is essential to the reliability of any system. On an error, such code is responsible for releasing acquired resources to restore the system to a viable state. Missing resource-release operations can lead to system crashes, memory leaks and deadlocks. A number of approaches have been proposed to detect such problems, but they mainly target frequently occurring resource-release operations. In this paper, we propose a novel approach to finding resource-release omission faults, focusing on error-handling code. Our approach achieves precision and scalability by exploiting information available within each function definition itself. Using a tool, EHCtor, that we have developed based on this approach, we have found over 370 faults in six different C infrastructure software projects, with a false positive rate well below the 30% that has been reported to be acceptable to developers. Some of these faults are exploitable by an unprivileged malicious user, making it possible to crash the entire system.