When starting your own company, it is easy to find competition everywhere. Every market map has a dozen logos on it. Every investor asks who else is doing this. Every product launch from a company vaguely near your space lands in your inbox…
When starting your own company, it is easy to find competition everywhere. Every market map has a dozen logos on it. Every investor asks who else is doing this. Every product launch from a company vaguely near your space lands in your inbox…
I am a software engineer, and I used to enjoy arguing with people for technical correctness. Code reviews, design meetings, mailing-list threads, dinner tables. If someone was wrong, I wanted them to know it, and I wanted them to know exact…
AI can now tell you whether code works. It reviews patches, spots bugs, suggests fixes, and explains trade-offs. Correctness is becoming cheap. Competence is being commoditized. But there’s something AI cannot do: tell you whether something…
The evolution of eBPF (extended Berkeley Packet Filter) has been one of the most significant developments in Linux system observability and networking over the past decade. As we look at the landscape in early 2025, several key trends have
I’m Cong Wang, a software engineer and entrepreneur based in California. Originally from China, I’ve spent my career working at the intersection of operating systems, networking, and performance optimization. I’m currently the Founder and C…
If you’ve been following the Linux kernel development community over the past few years, you might have noticed an interesting emerging trend in the field of memory persistence when using kexec to boot into a new kernel. Between 2020 and 20…
The Extended Berkeley Packet Filter (eBPF) has revolutionized how we extend and observe the Linux kernel. However, with great power comes great responsibility, and securing eBPF programs has been a persistent challenge in the Linux kernel c…
I have been mentoring our interns for some eBPF projects. The most common question raised during their internship is about the eBPF struct __sk_buff. It seems there is no document on Internet explains why it is introduced and how it works.
Like many other areas, surprisingly it is not even hard to pretend to be an expert in Linux kernel, as long as you can talk so much bullshit that even others don’t want to challenge your authority on this topic. Especially in United States,…
This is a very interesting challenge of reversing. It turns out to be more than just reversing, it requires some knowledge of image processing too, as we will see. First, once you read into the challenge, the boxy.txt contains many hints fo…
The series of x86 assembly challenges in CSAW CTF are interesting, because it wraps with a very tiny i386 OS! How I miss the good old days of hand writing i386 boot assembly! Part 1 is fairly elementary, I don’t want to waste a word on it.