Jakob's Personal Webpage

"funsignals" was a 250 point binary exploitation challenge with 58 solves. The challenge itself was a very trivial example of sigreturn-oriented programming.

Last night – Thursday, May 12th, 2022, at 22:17L – my cat was put to rest. I tend to avoid publishing anything non-technical to this website, but she deserves to be remembered, and this is the only place I can be confident my writing will last. She'd been with me through most of my life, always bringing me comfort when I was stressed, and keeping watch over me when I was sick. I owe this to her.

This was the first year our capture-the-flag event, UMass CTF 2021 , was open to the public. The competition started Friday, March 26th at 18:00 EDT, and ended Sunday, March 8th at the same time. By the end of the competition, we had 1991 registered users , belonging to 1160 registered teams . No teams were tied, we had just one unsolved challenge, and each of the "harder" challenges had just one…

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.

At a first glance, it might seem that game cheats like AimTux are something that could only be conjured by the most talented of reverse engineers. That was at least my initial view on it, especially since I always saw these game hackers using outlandish terms that I hadn't heard in over a year of playing in CTF's. Don't be fooled; game hacking isn't nearly as complex as its community makes it see…

In the introduction of the previous post I wrote for this series, First Impressions of the Rust Programming Language , I alluded to the presence of arguments that programming language safety should be achieved by moving to languages such as Java which run on a virtual machine. While "safety" may no longer be the first thing that comes to mind in discussion of these languages, especially with the …

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. ... This is a crosspost. Click here to read the rest of the article.

For the past ten months, I've been using my PinePhone as a "daily driver." By which, I mean it's been in my pocket everywhere I go, and it's the device I use to make phone calls. Depending on your familiarity with the PinePhone (or the state of "Linux Phones" more generally) this statement is either delirious, or vapid (why should I care that you use a "smart" phone just like the rest of us?) Don…

It's that time of year again where I take some time to reflect on UMass CTF . This is going to be shorter than last year's. I put out eight challenges, and I'm only going to be writing about one of them. Code, documentation, and write-ups for the others are available here .

This is a post I've been meaning to write for a while now: one anecdotally comparing programming languages in the Lisp family. I consider myself to be a Lisp hacker. Perhaps that much was obvious from the letter λ adorning my website's header, a reference to the λ-calculus which inspired John McCarthy to design the first LISP [1]. Yet, "Lisp hacker" likely means little unless you, too, consider y…

Packed lunches are a great way to save money, but being limited to foods palatable at room temperature (or colder) can be a little discouraging. In most American workplaces, a microwave oven is readily available in the breakroom, making it easy to reheat a home-cooked meal. However, after leaving a desk-bound white-collar job for one that often takes me into the field, that's only occasionally an…

When I started writing this article, I didn't mean to do anything more than describe a comment system I'd written in Guile. But as often happens when I write, I soon found myself disregarding that original scope and recording the history of every line of code I've written that's ever been run by a web server. I settled on allowing this to be an article about incorporating dynamic content into a …

Spaced repetition is an effective habit for memorizing small fragments of information for, effectively, an indefinite amount of time. The idea is to repeatedly challenge your recall of a piece of information, typically with a sort of flashcard , doing so at a frequency determined by your previous recall performance: new information is challenged frequently until you remember it, and previously le…

To start off, I'd like to say that I know very little about audio programming and digital audio in general. I've never formally studied signal processing, and hell, I haven't even started high school physics yet. This post merely documents what I've learned while trying to get sound working in my game, because there aren't really any other learning resources about this out there.

SDL2 is my favorite graphics library right now. It might not be as powerful as something like raw OpenGL, but it's simple. Simple enough that you can just pick it up and start using it. There's a glaring issue with it, though. The documentation is horrible. Absolutely horrible. A lot of it is unfinished, and it doesn't look like it's getting attention any time soon. The SDL1.2 documentation wasn'…

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.

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 .

I started working on my master's degree last September. The goal was to return to my workplace as a domain expert in formal methods – a topic I knew I was interested in, and yet something I knew practically nothing about. I partially attribute my lack of exposure to the lack of supervised learning opportunities (courses) at my undergraduate institution. Brown has an ample supply of teaching and r…

My capture-the-flag team played in the Insomni'hack teaser this year. During the competition, I worked on a single challenge titled "sapeloshop." It was labeled as "Medium-Hard," and it was in the binary exploitation category. The source code for the server wasn't provided, so reverse engineering was necessary. I don't think that having to reverse the binary was supposed to be the hard part, as m…

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…