OS Kernel Isolation for Context-violation Bugs

Context-violation bugs corrupt kernel heap objects unrelated to the current execution context and often preserve the original control flow, thereby evading existing control-flow integrity checks. Memory isolation is essential for mitigating unexpected behaviors of commodity operating systems (OSes) caused by software bugs or malicious attacks. However, existing isolation techniques are typically component-specific and protect only a limited set of kernel objects, leaving OS kernels vulnerable to error propagation caused by context-violation bugs. This paper presents kernel-context domains (KC-domains), a protection domain mechanism for isolating monolithic kernels. KC-domains restrict each kernel context to access only the kernel objects necessary for its execution by dynamically updating access permissions. We implemented a prototype on an xv6-based kernel running on x86-64 and conducted preliminary experiments. The results show that the prototype protects the OS kernel with a runtime overhead ranging from 1.08× to 3.05×.