Jan Schaumann

Working in tech, I'm profoundly torn based on my belief that the internet is one of the fundamentally best things we've accomplished, full of promise and possibility, and at the same time knowing that we've completely fucked it up in how we're using it and the effect technology has on us and our […]

In the previous post above, I looked at the arrangement of thread stacks in virtual memory. That leads to the question: can one thread reach over into the other thread and monkey with its local variables? And how is that different from a forked process, which has the same memory layout as its […]

R: If you don't let us take away people's health insurance, we'll literally starve them.

D: That seems bad.

R: Also, we'll fire people and not have backpay for those we keep.

D: As a compromise, can you pinky promise not to fire more people, and then we'll let you take away people's health […]

I'm grading student papers, and I can report that one effect of generative AI is that I now suspect everything my students submit. And that's not a good place to be in while grading.

#banGenAIfromUniversities

@rwg The depressing thing is that this holds not just for results that look too good, but likewise for just mediocre results. Too many similarities to be coincidence, and still a B- at best. At least the Fs tend to be unique. :-/

Not every time a computer is involved in an algorithmic decision is that necessarily “AI”.

That’s all. Thanks for coming to my TED talk.

In the previous post above, I looked at the arrangement of thread stacks in virtual memory. That leads to the question: can one thread reach over into the other thread and monkey with its local variables? And how is that different from a forked process, which has the same memory layout as its […]

Advanced Programming in the Unix Environment

Week 9: I/O Multiplexing

With this video, we complete our discussion of interprocess communication and move from one-to-one communications towards a more typical client-server model with a server side process capable of handling multiple […]

Why, yes, nuking >470 lines of code and replacing them with a comment can make passing tests easier. AI generated pull requests FTW […]

@adamshostack Any container, really. I agree that many of the protections that underlie containers are useful, but in the end you are still running within the same OS on the same hardware.

You know, if you consider containers a security boundary, then you've pretty much already lost. I mean, they're useful and all, but maybe think of them more like crowd line dividers or barriers, not like concrete walls.

Advanced Programming in the Unix Environment

Week 9: socket(PF_INET6, SOCK_STREAM, 0)

In this video, we demonstrate sockets using TCP to establish a sequenced, reliable, two-way byte stream over an #IPv6 network. Our good friend tcpdump(8) helps us inspect the packets on the wire to observe […]

Advanced Programming in the Unix Environment

Week 9: socket(PF_INET, SOCK_DGRAM, 0)

We're finally moving on to network communications, and show how to communicate between hosts across the internet using datagram sockets in the PF_INET domain, that is, via UDP. We also observe the packets as […]

Advanced Programming in the Unix Environment

Week 9: socket(PF_LOCAL, SOCK_DGRAM, 0)

Following up on socketpairs, we're continuing our discussion of the sockets API by an example of datagram connections in the PF_LOCAL (formerly AF_UNIX) domain.

https://youtu.be/7LoLt49oB9A

#apue #unix […]

If you're using `runc` for your containers: congrats! You get to patch three new vulnerabilities that could allow for a full container break-out:

CVE-2025-31133: symlink attack on bind-mount of /dev/null for masked paths […]

Oh,fuck yeah! A day starting with the grim reaper coming for an old, evil fuck and ending with young democrats being elected! I like it, gimme more of both!

Advanced Programming in the Unix Environment

Week 9: socketpair(2)

Let's continue with the above mentioned IPC tutorial and discuss the socketpair(2) system call and compare its functionality with that of the pipe(2) call. This introduces the concept of sockets, domains, and protocols, which […]

Happy "Even if you sell your soul to the devil, he will eventually come and collect it." Day to all who celebrate! 🎉 There's hope yet!

Bug Bounty Facts:

With enough eyeballs, all bugs reported to you are shallow.

Advanced Programming in the Unix Environment

Did you know that #NetBSD comes with a number of historical Unix research papers and supplementary documentation? Here, we find papers by Marshall Kirk McKusick on the Fast File System, by Robert Morris and Ken Thompson on Password Security, a shell […]

Advanced Programming in the Unix Environment

Week 8: Pipes and FIFOs

With this video lecture, we continue our discussion of Interprocess Communication and dive into two of the oldest and most ubiquitous forms of Unix IPC: pipes and FIFOs. We also discuss popen(3) and the dangers of shelling […]

Me: You have to check the return value of malloc(3) and other functions.

My students: Ok.

p = malloc(num);
if (p == NULL) {
}
do-stuff-with p

Advanced Programming in the Unix Environment

Week 8: System V IPC

In this video lecture, we cover traditional, primarily asynchronous System V Inter Process Communication: semaphores, shared memory, and message queues. We then also take a brief look at the POSIX message queues implementation. […]

Photo of a hoatzin

TIL: the Hoatzin

Contemporary flying dinosaur. Entirely folivorous, effectively a ruminant (complete with methane belches), shitty at flying, loud and stinky, and the chicks have claws like an archaeopteryx.

Birds, man. Bird is the word.

You know, everything I see from BlueSky over here on Mastodon is either "you need to sign in to view this post" or some very angry doomscroll fodder that makes me think I'm really not missing much from that outrage machine over there.

Pretty sure unfollowing 95% of bsky.bridge accounts won't be […]

Advanced Programming in the Unix Environment

Week 8: Interprocess Communications Intro

This week, we begin our discussion of Interprocess Communication. We start by providing a quick overview of the different properties of IPC mechanisms as well as which mechanisms we will cover […]

I fell down a rabbit hole into a virtual memory layout landscape, trying to better understand how thread stacks are placed under Address Space Layout Randomization. Turns out, there's quite a bit of variability across different Unix flavors.

https://www.netmeister.org/blog/thread-stacks.html […]

Quite a month for cloud providers, huh? First #aws, now #azure.

The great thing is y'all can just recycle your previous comments noting eggs, baskets, monocultures, tech giant dominance, etc. here. Just save a few for GCP next week.

Screengrab: Tommy Lee Jones from "No Country for Old Men" looking over his reading glasses, newspaper in hand.

Me when "hackers" ask for a reward for reporting a vulnerability of "weak SSH ciphers" on a hostname that resolves to 127.0.0.1.

Cloudflare just posted about 5 or 6 blog posts in one on #PQC:

"State of the post-quantum Internet in 2025" - https://blog.cloudflare.com/pq-2025/

Nothing really new if you've been following the topic, but very comprehensive if you want to catch up on the current state.

Also interesting: they […]