Reverse Engineering Dropbox

May 17, 2019 by Al Williams 7 Comments

These days everyone talks about data “in the cloud.” However, before that phrase was fashionable, there were a few pioneers and one of the most famous of these is Dropbox — a service that let you store files on a remote server that dates back to 2007. [Vincent Berg] first noticed some odd network traffic on a hotel network, and figured out that it was a feature of Dropbox that allows computers on the same network to update each other. This led him to start investigating the undocumented Dropbox protocol and reverse engineering the Linux client.

We won’t ask why [Vincent] was poking around the hotel network to start with. However, a cursory glance at the Dropbox client gave away that it was using Python. The byte-compiled classes were — at the time — in a ZIP file added to the executable (which was nothing but a modified copy of Python). The files were encrypted, but [Vincent] used a clever technique. He built a shared object using normal Python and put a backdoor in it that gave him access to the Dropbox Python interpreter.

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Mathics: How To Do Hard Math When You’re Not An MIT Janitor

May 11, 2019 by Al Williams 27 Comments

Algebra is the bane of many a student, but it is surprisingly useful when it comes to electronics. Sure, you can just memorize all the permutations of things like Ohm’s law. But it is better if you can remember one form and deduce the others on the fly.

There are many occasions where you — as our old Algebra teacher used to say — need to use what you know to get what you don’t know. The gold standard, of course, is a computer program called Mathematica. For home and student use, the software is “only” about $160-$600, but commercial versions range from about $1,000 to nearly $8,000. Of course, there are free alternatives, and the one we’re looking at today is Mathics. It will run in your browser or as a desktop application powered by Python, and it’s available for free.

The program does a nice job of displaying mathematical formulae and you can get an idea of its power by visit the online version. which has examples if you click the question-mark in the upper right and look for the fourth item down. There’s also a standalone version of the online help.

We did have a little trouble with some of the gallery examples timing out, as well as the site certificate being expired. We also had a bit of difficulty remembering the linear algebra classes we took a long time ago! If you want something easy to play with try this:

Solve[4x+3==20,x]

Don’t forget to press Shift+Enter in the browser to get the solution.

Under the hood, MathJax and SymPy do a lot of the heavy lifting. In fact, we imagine a lot of the program’s intended audience would wind up using Jupyter notebooks with Python underneath. Of course, there are copies of Wolfram software on stock Raspberry Pi’s, too.

Fortran Goes Interactive

May 3, 2019 by Al Williams 8 Comments

When you think of Fortran you probably think of punched cards and green bar paper. While it is true that Fortran isn’t the go-to language it used to be — pun unintentional — it still has a vibrant community of people who do serious number crunching. However, many members of that community have been seduced away by interactive tools that are also good at number crunching like MATLAB, Julian, and Python with special libraries. The LFortran project aims to create a Fortran environment with interactivity like Python, but retaining the speed that Fortran is known for.

The resulting tool is impressive. You can use it from Jupyter, can parse code targeting existing Fortran compilers, and supports Linux, Mac, and Windows. There is development to make the code fully interoperable with other languages like C or Python as well as take advantage of GPUs and other specialized hardware. They are also zeroing in on full Fortran 2018 support.

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Raspberry Pi Streams Music Using Only The Default Linux Tools

May 2, 2019 by Bryan Cockfield 13 Comments

Getting a home music streaming system off the ground is typically a straightforward task. Using Apple devices with Airplay makes this task trivial, but if you’re a computing purist like [Connor] who runs a Linux machine and wants to keep it light on extra packages, the task gets complicated quickly. His goal is to bring audio streaming to all Linux platforms without the need to install a lot of extra software. This approach is friendly to light-footprint devices like the Raspberry Pi that he used in his proof of concept.

[Connor] created a set of scripts which allow streaming from any UNIX (or UNIX-like) machines, using only dependencies that a typical OS install would already have. His Raspberry Pi is the base station and streams to his laptop, but he notes that this will work between virtually any UNIX or Linux machine. The only limitation is what FFmpeg can or can’t play.

We definitely can appreciate a principled approach to software and its use, although it does seem that most people don’t have this issue at the forefront of their minds. This results in a lot of software that is bulky, making it difficult to maintain, use, or even know what it does, and also makes it harder for those of us that don’t want to use that type of software to find working solutions to other problems. It’s noble that [Connor] was able to create something without sacrificing any principles.

KiCad Gets Banana For Scale

May 2, 2019 by Brian Benchoff 38 Comments

Over the years we’ve seen KiCad grow from a niche, somewhat incomplete, but Open Source PCB design suite to a full-featured extravaganza of schematics and board layouts. We’ve plumbed the depths of keys and kais and queues and quays, and KiCad just had its first conference last weekend. While we wait for the rest of the talks to be published, there’s a special treat for KiCad users everywhere. Here’s a banana for scale.

Have you ever worried your PCB was too big? Confused if you’re working in inches or millimeters? Do you just want to know the scale of your PCB? Just add this footprint to your KiCad project, and you’ll have a banana on your board view. This is immediate visual feedback, giving you all the information you need to continue on with your design. There’s a 2D view and a 3D view. It’s something no electrical engineer should be without. All of this can be yours for the low, low, cost of free because KiCad is Open Source.

If you’re wondering what official features are in the works for the EDA suite, the first two talks from the con delve into that. project leader Wayne Stambaugh’s talk covers features new to version 5.1 and plans for 6.0. There was also a developers panel that provides insight on what goes into a large project like this one.

Easter Egg Turns Nintendo Switch Into A Development Platform

April 29, 2019 by Al Williams 5 Comments

Like a lot of game developers [Amir Rajan] likes to put Easter Eggs into his creations. His latest Nintendo Switch title, A Dark Room, has a very peculiar one, though. Instead of a graphic or a Tetris game, [Amir] put a code editor and a Ruby interpreter in the game.

Ruby is a language that originated in Japan and is popular with Web developers, in particular. It has dynamic typing, garbage collection, and supports several different programming styles. We aren’t sure what you’d do with it on a Nintendo Switch, but any time we can program a gadget, it makes us happy.

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Pano Logic FGPA Hacking Just Got Easier

April 19, 2019 by Tom Nardi 8 Comments

When Pano Logic went out of business in 2012, their line of unique FPGA-based thin clients suddenly became a burden that IT departments didn’t want anything to do with. New and used units flooded the second-hand market, and for a while you could pick these interesting gadgets up for not much more than the cost of shipping. Thanks to considerable interest from the hacking community the prices for these boxes have climbed a bit on eBay, but they’re still a great way to get your feet wet with FPGA hacking.

Especially now, as Pano Logic fanatic [Skip Hansen] has figured out how to flash a new firmware on them without having to crack open the case and break out the JTAG or SPI programmer. For the seasoned hardware hacker that might not seem like a big deal, but if you’re new to the game or just more interested in the software side of the equation, this trick makes things considerably more accessible. Having an external programmer is still a good idea if things go south, but if you’re just looking to flash some demos and see what the hardware is capable of this is a huge quality of life improvement.

Even if you aren’t interested in fiddling with the orphaned products of a defunct Bay Area startup, the write-up is a fascinating look at practical software reverse engineering. As it turns out, [Skip] didn’t create this new firmware update tool from scratch. He actually opened up the official Linux update utility from Pano Logic in Ghidra and was able to figure out where the firmware image actually lived inside the program. He then wrote his own tool in C which will patch the update tool with a user-supplied firmware image.

After patching, all you need to do is follow the official update procedure, which Pano Logic helpfully documented in the YouTube video after the break. [Skip] mentions he didn’t find any clear license information in the official software he was fiddling with, and of course with the company out of business it’s not too likely anyone is going to come knocking down his door anyway. Still, he says the downloads for the Pano Logic updater are still floating around on the tubes out there for you to find, so he’s not distributing anyone’s code but his own in this project.

There are a number of hackers out there working to turn the Pano Logic thin clients into useful general purpose FPGA platforms, such as [Tom Verbeure], who’s incredible graphics demos got [Skip] inspired to grab his own unit off eBay. With support for USB and SDRAM added by [Wenting Zhang] while getting his FPGA GBA emulator running on the hardware, it seems there’s never been a better time to get on the Pano Logic train.

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