The Linux distribution kernel differs significantly from the mainline kernel, incorporating additional features and vendor-specific extensions. Among these additions, many runtime parameter interfaces are unique to distribution kernels, which expands the attack surface and increases the risk of potential vulnerabilities. Fuzzing has been used to assess Linux distributions, but existing tools cannot systematically test these distribution-specific interfaces due to two main challenges: (1) generating test cases for these runtime parameter interfaces, and (2) concentrating test resources on the distribution-specific interface code. To address these challenges, we propose RPG, a distribution-specific runtime parameter-guided kernel fuzzer. RPG operates in three phases: First, RPG extracts distribution-specific runtime parameter interfaces. Then, RPG uses LLM and tuning software databases to model each parameter range to generate meaningful interface test cases. Third, RPG utilizes the distribution kernel’s function control flow graph to guide the fuzzer to generate generic test cases that are more closely related to the distribution-specific interface code. We evaluated RPG on four Linux distribution kernels: Ubuntu 22.04, Fedora 42, OpenAnolis 8.8, and OpenAnolis 23.1. RPG detected 22 previously unknown bugs (13 distribution-specific), of which 15 were confirmed and 10 fixed by kernel maintainers. RPG also achieved 20.4% and 21.2% higher branch coverage than Syzkaller and Healer, respectively.

Kata Containers is a secure container runtime with lightweight virtual machines and a customized Linux kernel optimized for cloud-native workloads, which is important for cloud-native systems. Fuzzing is a widely-used technique for detecting kernel vulnerability. However, current kernel fuzzers can't be simply applied to kernels in cloud-native environments because of the discrepancies between test and actual deployment scenarios. This paper introduces DragonRadar, a kernel fuzzing tool adapted for Kata Containers, which aligns the testing environment with cloud deployment realities. We extend to support kernel fuzzing in cloud-native environments by integrating Syzkaller's capability with a lightweight virtual machine manager called Dragonball. The evaluation shows that DragonRadar effectively identifies 25 kernel vulnerabilities in the mainline Linux kernel used in the Kata Containers environment, while maintaining code coverage similar to vanilla Syzkaller. DragonRadar is available at https://github.com/TOBESTONG//DragonRadar.