December 29, 2019 ❖ Tags: writeup, reverse-engineering, x86
This is the fourth and final set of for my self-imposed challenge of completing at least fifty of the exercises on Dennis Yurichev's challenges.re by the end of the year. The previous set is available here.
August 18, 2019 ❖ Tags: writeup, reverse-engineering, x86
This is the third set of solutions for my self-imposed challenge of completing at least fifty of the exercises on Dennis Yurichev's challenges.re by the end of the year. The previous set is available here.
July 13, 2019 ↻ Crosspost ❖ Tags: writeup, programming, functional-programming, linux, guix, lisp, scheme, guile
Hey, there! I'm Jakob, a Google Summer of Code intern and new contributor to Guix. Since May, I've been working on a DevOps automation tool for the Guix System, which we've been calling guix deploy.
May 28, 2019 ❖ Tags: writeup, reverse-engineering, x86
This is the second set of solutions for my self-imposed challenge of completing at least fifty of the exercises on Dennis Yurichev's challenges.re by the end of the year. The first set is available here.
May 04, 2019 ❖ Tags: writeup, programming, lisp, scheme, emacs, emacs-lisp
Rather than study for finals this week, I spent my time moving this blog over to Haunt. Previously, I was using Hugo, and while ox-hugo made the authoring workflow tolerable, doing anything on the rendering side of things was unsavory at best. I eventually had enough and decided to look for another solution, of which Haunt was the most enticing.
April 14, 2019 ❖ Tags: writeup, security, reverse-engineering, capture-the-flag, x86, c, python
My long-lived hiatus from capture-the-flag has come to an end, as I got off my ass this weekend to play in PlaidCTF 2019. Being a one-man team is pretty lonely, but my old team wasn't playing, and even if they were, I don't know if I would've wanted to make the commute just to play with them.
March 10, 2019 ❖ Tags: writeup, reverse-engineering, arm, x86
As mentioned in the (now deleted) post I wrote describing my plans for 2019, one of my goals this year is to get through at least 50 of the exercises on Dennis Yurichev's challenges.re. I've decided to document my progress in the form of writeups for the challenges I complete, batched in sets of ten exercises. For each challenge, I'll try to explain the intuitions that brought me closer to answering the recurring question from Yurichev, "[w]hat does this code do?"
November 02, 2018 ❖ Tags: writeup, video-games, programming, game-development, lua, lisp, fennel
Slime the World was my entry to this year's Autumn Lisp Game Jam, and it managed to win second place. The theme was slime, so it’s a game about covering everything in sight with slime, and the dialect of Lisp I chose to use was Fennel, a simple and elegant Lisp that I feel perfectly matches the simplicity and elegance of Lua. It takes on a more "modern" style that I associate with Lisps such as Clojure. I had initially pushed Clojure to the side, feeling it was too different from Common Lisp, but now that I've had a positive firsthand experience with a Lisp where lists aren't the data structure you always reach for, I'm hoping to return to it with an open mind.
January 13, 2018 ❖ Tags: writeup, programming, video-games, audio, c++
My first experiences with Duke Nukem 3D were with EDuke32 ages ago. This was back when I was running Windows Vista, and while my memory is a bit lacking, I swear that I had working music then. Ever since I made the switch to Linux, I haven't had working music playback in EDuke. Frustrated at the fact that my past few years of Duke 3D have been devoid of all sound besides the screams of death and Duke's trash talking, I've finally decided to troubleshoot it.
January 04, 2018 ❖ Tags: writeup, security, binary-exploitation, video-games, x86, doom
TL;DR, I discovered a stack-smashing vulnerability in GZDoom's interpreter for ACS. As a preface, there's a tendency for whitepapers like this in the security community to be written with a somewhat condescending tone towards the product's vendor. I do not mean for any portion of this writeup to come off as degrading to the developers involved. Yes, the bug was obvious to me, but it was still subtle enough that it went under the radar for nearly 23 years. Most developers aren't actively thinking about this kind of attack while writing a bytecode interpreter. I have an enormous amount of respect for the development teams of both GZDoom and Zandronum, who were quick to issue a patch addressing the issue and were respectful of my wishes to release this whitepaper to the public. I'd also like to thank everyone I had the pleasure of working with during this process; it warms my heart to know that the communities behind these open-source software projects are this friendly.