This Week In Security: Curl Reveal, Rapid Reset DDoS, And Libcue

October 13, 2023 by Jonathan Bennett 17 Comments

Curl gave us all a big warning that a severe security problem had been found in that code-base. Given the staggering number of Curl installs around the world, we held our collective breath and waited for the bombshell to drop this Wednesday. It turns out, it’s not quite as bad as feared — so long as you don’t have a SOCKS proxy.

In hindsight, shipping a heap overflow in code installed in over twenty billion instances is not an experience I would recommend. — Daniel Stenberg

The trouble started when the SOCKS5 proxy support was converted to a non-blocking implementation. It’s a win for libcurl to work on requests asynchronously, but refactoring code and new features always runs a bit of risk. SOCKS5 proxying has some quirks, like allowing DNS resolution to happen locally or at the proxy. The new async code starts out with:

bool socks5_resolve_local = (proxytype == CURLPROXY_SOCKS5) ? TRUE : FALSE;

First off, unnecessary ternary is unnecessary. But note that this local variable gets set by the proxytype. If that’s CURLPROXY_SOCKS5_HOSTNAME, then it uses remote resolution. But inherited from old code is a check for a hostname that is too long for a SOCKS request (255 bytes). This code converts back to local resolution in this case.

The important detail here is that this function is now a state machine, that potentially runs multiple times for a single request, to achieve that asynchronous execution. The check for a too-long hostname only happens during the initialization state. Copying the hostname into the buffer happens in a different state. If setting up the connection takes enough time, the function will return and be executed again when something has changed. The ternary check runs again, but not the hostname-too-long. So if set to do remote resolution with a long enough host name, execution slips through this edge case, and the long hostname is copied into a too-small buffer.

It’s safe to assume that this heap overflow can result in arbitrary code execution. The fix has landed in 8.4.0, after being present for 1,315 days. [Daniel] goes ahead and gets ahead of the inevitable suggestion that Curl should be written in rust or another memory-safe language. Curl was started before those alternatives existed, and there is a very slow effort to move portions of the project to memory-safe languages. And you’re welcome to help out. Continue reading “This Week In Security: Curl Reveal, Rapid Reset DDoS, And Libcue” →

USB-C For Hackers: Build Your Own PSU

October 12, 2023 by Arya Voronova 43 Comments

What if you wanted to build your own USB-C PSU? Good news – it’s easy enough! If you ever wanted to retrofit a decent DC PSU of yours to the USB-C standard, say, you got a Lenovo/HP/Dell 19V-20V charger brick and you’ve ever wished it were USB-C, today is the day when we do exactly that. To be fair, we will cheat a bit – but only a tiny bit, we won’t be deviating too much from the specification! And, to begin with, I’ll show you some exceptionally easy ways that you can turn your DC PSU into a USB-C compatible one, with a simple module or a few.

Turning a 20 V PSU into a USB-C PSU feels natural if you want to charge a laptop – those tend to request 20 V from a USB-C PSU anyway, so what’s the big deal? However, you can’t just put 20 V onto a USB-C connector – you have to add a fair bit of extra logic to make your newly christened USB-C PSU safe to use with 5 V devices, and this logic also requires you go through a few extra steps before 20 V appears on VBUS. Any USB-C PSU has to output 5 V first and foremost whenever a device is connected, up until a higher voltage is negotiated digitally, and the PSU may only switch to a higher voltage output when it’s requested to do so.

Now, for that, a PSU offers a list of profiles, and we looked into those profiles in the Replying PD article – each profile is four bytes that contain information about the profile voltage, maximum current that the device may draw at that voltage, and a few other details. For a PSU to be USB-C compliant, the USB-C specification says that, in addition to 5 V, you may also offer 9 V, 15 V, and 20 V.

Also, the specification says that if a PSU supports certain in-spec voltage like 15 V, it’s also required by the spec to offer all of the spec-defined voltages below the maximum one – for 15 V, that also requires supporting 9 V. Both of these are UX requirements, as opposed to technical requirements – it’s easier for device and PSU manufacturers to work with a small set of pre-defined voltages that majority of the chargers will support, but in reality, you can actually offer any voltage you want in the PSU advertisement; at worst, a device is going to refuse and contend with slowly charging from the 5 V output that you’re required to produce.

I’d like to walk you through how off-the-shelf USB-C PSUs work, all of the options you can use to to create one, and then, let’s build our own USB-C PSU from scratch! Continue reading “USB-C For Hackers: Build Your Own PSU” →

Hackaday Superconference 2023: Workshops Announced, Get Tickets Now!

October 12, 2023 by Elliot Williams 4 Comments

Last week, we announced just half of our fantastic slate of talks for Supercon. This week, we’re opening up the workshops. The workshops are small, hands-on opportunities to build something or learn something, lead by an expert in the field. Workshops sell out fast, so register now if you’re interested.

And stay tuned for the next round of talk reveals next week! And maybe even the badge reveal?

Andy Geppert
Weave Your Own Core Memory – Core16!

This workshop provides you with the opportunity to weave your own core memory! Using 16 authentic ferrite core bits and 16 RGB LEDs, you can play tic-tac-toe, paint with a magnetic stylus, and create your own interactive experiences. Andy Geppert will guide you through the assembly of Core16. The Core16 kit is the little brother of the Core64 kit. The smaller Core16 kit reduces assembly time/cost, enabling more people to experience the challenge and satisfaction of creating their own core memory.

Travis Foss
Presented by DigiKey: Introduction and expansion of the XRP Robotics Platform

In this workshop you will be able to get your hands on the new XRP (Experiential Robotics Platform) and take the basics a step further with a few additional parts. Along with the base kit, participants will have the opportunity to install a RGB twist encoder, a LCD screen, and a buzzer to create a setup that will allow the user to choose a program onboard without being tethered to a computer.

Becky Button
How to Make a Custom Guitar Pedal

Musical effects are for everybody! Join this workshop and get hands-on experience assembling and programming your musical effects pedals. Walk away from this workshop with the capability of integrating multiple musical effects into 1 device and reprogramming the pedal with any effects you want!

Daniel Lindmark
From Zero to Git: 1 Hour Hardware Git Bootcamp

In this workshop, you will learn all about basic git operations, including how to download and install the client, setting up a repo, synching changes, and much more. Learn how to navigate common issues and take advantage of a live FAQ during the workshop.

Jazmin Hernandez
Solder and Learn How to Use Your Own Anti-Skimmer (HunterCat)

Have you ever been vulnerable to data theft? Do you fear using your bank card in ATMs or even in a restaurant? Protect your information from potential skimmers in this workshop while you learn to solder some components of your anti-skimmer/magnetic stripe clone detectors. By the end of the workshop, you’ll have a device to insert before using your bank card to check for potential issues.

Matt Venn
Tiny Tapeout – Demystifying Microchip Design and Manufacture

In this workshop, you can design and manufacture your own chip on an ASIC. You will learn the basics of digital logic, how semiconductors are made, the skills needed to use an online digital design tool for simulation, and how to create the GDS file for manufacturing. Participants will also have the option to submit their designs to be manufactured as part of the Tiny Tapeout project.

You can’t attend the workshops without attending Supercon, so get your tickets! (As we write, there are only ten more…)

You’ve Got Mail: It All Depends On ZIP Code

October 12, 2023 by Kristina Panos 26 Comments

Previously on You’ve Got Mail, we looked at a few services that were designed to speed up the mail at various points along the way. But these improvements were all taking place on the USPS’ side of the the fence. Was there anything the customer could be doing to help out?

As it turns out, yes. And it was almost too late. Whereas you could once address a letter or postcard simply to “Fred Minke, Somerset, Wis.” and it would reach him, the volume of mail was getting completely out of hand with the rise of computers, automated billing, and advertising. Something was needed to improve routing and speed up delivery.

We all know enough about ZIP codes to use them, but where did they come from? How many types are out there? What do they even mean? Let’s find out.

Continue reading “You’ve Got Mail: It All Depends On ZIP Code” →

Meshtastic And Owntracks To Kick Your Google Habit

October 11, 2023 by Jonathan Bennett 20 Comments

I have an admission to make. I have a Google addiction. Not the normal addiction — I have a problem with Google Maps, and the timeline feature. I know, I’m giving my location data to Google, who does who-knows-what-all with it. But it’s convenient to have an easy way to share location with my wife, and very useful to track my business related travel for each month. What we could really use is a self-hosted, open source system to track locations and display location history. And for bonus points, let’s include some extra features, like the ability to track vehicles, kids, and pets that aren’t carrying a dedicated Internet connection.

You can read the title — you know where we’re going with this. We’re setting up an Owntracks service, and then tying it to Meshtastic for off-Internet usability. The backbone that makes this work is MQTT, a network message bus that has really found its niche in the Home Assistant project among others. It’s a simple protocol, where clients send brief messages labeled by topic, and can also subscribe to specific topics. For this little endeavor we’ll use the Mosquito MQTT broker.

One of the nice things about MQTT is that the messages are all text strings, and often take the form of JSON. When trying to get two applications to talking using a shared MQTT server, there may need to be a bit of translation. One application may label a field latitude, and the other shortens it to lat. The glue code to put these together is often known as an MQTT translator, or sometimes an MQTT bridge. This is a program that listens to a given topic, ingests each message, and sends it back to the MQTT server in a different format and topic name.

The last piece is Owntracks, which has a recorder project, which pulls locations from the MQTT server, and stores it locally. Then there’s Owntracks Frontend, which is a much nicer user interface, with some nice features like viewing movement a day at a time. Continue reading “Meshtastic And Owntracks To Kick Your Google Habit” →

Jenny’s Daily Drivers: SerenityOS, And In Particular, Ladybird

October 10, 2023 by Jenny List 35 Comments

As we continue on with the series in which I take a different OS for a spin every month I am afraid, dear reader, that this month I have a confession to make. Our subject here isn’t a Daily Driver at all, and it’s not the fault of the operating system in question. Instead I’m taking a look at a subject that’s not quite ready for the big time but is interesting for another reason. The OS is SerenityOS, which describes itself as “a love letter to ’90s user interfaces with a custom Unix-like core“, and the reason I’m interested in it comes from its web browser. I know that the OS is very much a work in progress and I’ll have to forgo my usual real hardware and run it in QEMU, but I’ve heard good things about it and I want to try it. The browser in question is called Ladybird, and it’s interesting because it has the aim of creating a modern fully capable cross-platform browser from scratch, rather than being yet another WebKit-based appliance.

A Pleasant Trip Into The 1990s

Part of a Linux desktop with the SerenityOS build instructions in the background, a terminal having built the OS, and the OS itself in a QEMU window. — My first look at SerenityOS after building it.

SerenityOS isn’t ready to be installed on real hardware, and there’s no handy ISO to download. Instead I had to clone the repository to my Linux machine and run the build script to compile the whole thing, something I was very pleased to observe only took about 40 minutes. It creates a hard disk image and opens QEMU for you, and you’re straight into a desktop.

When they mention ’90s user interfaces they definitely weren’t hiding anything, because what I found myself in could have easily been a Windows 9x desktop from the middle of that decade. There are a bunch of themes including some Mac-like ones, but should you select the “Redmond” one, you’re on very familiar ground if you had a Microsoft environment back then. It’s only skin-deep though, because as soon as you venture into a command line shell there’s no DOS to be found. This is a UNIX-like operating system, so backslashes are not allowed and it’s familiarly similar to an equivalent on my Linux box. The purpose of this review is not to dive too far into the workings of the OS, but suffice it to say that both the underpinnings and the desktop feel stable and as polished as a Windows 95 lookalike can be. The various bundled utilities and other small programs seem to work well, and without any hint of the instabilities I’ve become used to when I’ve experimented with other esoteric operating systems. Continue reading “Jenny’s Daily Drivers: SerenityOS, And In Particular, Ladybird” →

Illustrated Kristina with an IBM Model M keyboard floating between her hands.

Keebin’ With Kristina: The One With The Arboreal Keyboards

October 9, 2023 by Kristina Panos 6 Comments

Well, unfortunately we don’t know much yet about this nice wooden keyboard from [Kelvin Chow], but maybe this inclusion will encourage [Kelvin] to post more about it.

Sure is nice-looking, don’t you think? That’s because there some great details at play here, like the legend-less two-tone keycaps and the neat-o locking box it sits in.

This keyboard is inspired by the Hacoa Ki-board, which uses a singles plank of wood to craft the keycaps. [Kelvin] wanted to try this technique for themselves. Evidently this won’t be the last wooden keyboard, so stay tuned for more over on Hackaday.io.

This isn’t the first dead-tree keyboard we’ve seen around here, either. A while back we saw one with Scrabble tile keycaps, and earlier this year, a nice wooden macro pad.

Continue reading “Keebin’ With Kristina: The One With The Arboreal Keyboards” →