Junho Ahn, Jaehyeon Lee, Kanghyuk Lee, Wooseok Gwak, Minseong Hwang, and Youngjin Kwon, KAIST
Use-after-free bugs are an important class of vulnerabilities that often pose serious security threats. To prevent or detect use-after-free bugs, one-time allocators have recently gained attention for their better performance scalability and immediate detection of use-after-free bugs compared to garbage collection approaches. This paper introduces BUDAlloc, a one-time-allocator for detecting and protecting use-after-free bugs in unmodified binaries. The core idea is co-designing a user-level allocator and kernel by separating virtual and physical address management. The user-level allocator manages virtual address layout, eliminating the need for system calls when creating virtual alias, which is essential for reducing internal fragmentation caused by the one-time-allocator. BUDAlloc customizes the kernel page fault handler with eBPF for batching unmap requests when freeing objects. In SPEC CPU 2017, BUDAlloc achieves a 15% performance improvement over DangZero and reduces memory overhead by 61% compared to FFmalloc.
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author = {Junho Ahn and Jaehyeon Lee and Kanghyuk Lee and Wooseok Gwak and Minseong Hwang and Youngjin Kwon},
title = {{BUDAlloc}: Defeating {Use-After-Free} Bugs by Decoupling Virtual Address Management from Kernel},
booktitle = {33rd USENIX Security Symposium (USENIX Security 24)},
year = {2024},
isbn = {978-1-939133-44-1},
address = {Philadelphia, PA},
pages = {181--197},
url = {https://www.usenix.org/conference/usenixsecurity24/presentation/ahn},
publisher = {USENIX Association},
month = aug
}