Ahn, Junho 

Research Interests
Summary
System Security, Operating Systems, Extended Berkeley Packet Filter (eBPF), Memory Management

I am interested in designing secure and efficient operating systems.
To achieve this goal, my recent studies focus on 1) Defeating Use-After-Free with eBPF and 2) Rethinking operating system design with eBPF.

Overcoming Limitations of Extended Berkeley Packet Filter (eBPF)
Use-after-free (UAF) bugs are a critical class of vulnerabilities that often pose serious security threats. However, existing mechanisms for preventing or detecting UAF bugs have limitations in terms of performance and memory overhead. In a recent publication, I proposed an enhanced one-time allocator and garbage collection mechanism for UAF prevention and detection, leveraging an improved version of eBPF. This approach addresses these limitations by integrating operating system support with a novel user-level design.

Rethinking Operating System with eBPF
Isolation is a fundamental concept for protecting operating systems. However, synchronizing the user and the kernel between the isolation boundary leads to high overhead in the kernel stack, affecting performance. To address these challenges, I design an OS using eBPF to bridge the semantic gap. Recently, I proposed bypassing the kernel virtual address memory stack to implement efficient methods for transparently detecting use-after-free bugs in user-level applications. Additionally, I am involved in a project aiming to reinvent OS design concepts using Rust, leveraging efficient and safe OS concepts which is only possible with a language-based isolation model with Rust. 

From these sub-goals, I target enhancing Linux kernel with eBPF to bridge the semantic gap between the user and the kernel in a secure environment. It is expected to oversee novel application usage with a co-design model involving both applications and the kernel

Education

KAIST, Dajeon, Republic of Korea Mar 2023 -

 Ph.D. Student, School of Computing

 • Advisor: Youngjin Kwon

KAIST, Dajeon, Republic of Korea Mar 2021 - Feb 2023

 Mater of Science, School of Computing

 • Advisor: Youngjin Kwon

 • Thesis: vBPF: safely extending eBPF to enhance programmability and flexibility

GIST, Gwangju, Republic of Korea Mar 2017 - Feb 2021 

 Bachelor of Science, School of Electrical Engineering and Computer Science