Retrotechtacular: TVO

June 6, 2024 by 18 Comments

Hardware hackers come from a variety of backgrounds, but among us there remains a significant number whose taste for making things was forged through growing up in a farm environment. If that’s you then like me it’s probable that you’ll melt a little at the sight of an older tractor, and remember pretending to drive one like it at pre-school age, and then proudly driving it for real a few years later before you were smart enough to realise you’d been given the tedious job of repeatedly traversing a field at a slow speed in the blazing sun. For me those machines were Ford Majors and 5000s, Nuffields, the ubiquitous red Fergusons, and usually relegated to yard duty by the 1970s, the small grey Ferguson TE20s that are in many ways the ancestor of all modern tractors.

The Black Art Of Mixing Your Own Fuel

There was something odd about some of those grey Fergies in the 1970s, they didn’t run on diesel like their newer bretheren, nor did they run on petrol or gasoline like the family Austin. Instead they ran on an unexpected mixture of petrol and heating oil, which as far as a youthful me could figure out, was something of a black art to get right. I’d had my first encounter with Tractor Vapour Oil, or TVO, a curious interlude in the history of agricultural engineering. It brings together an obscure product of the petrochemical industry, a moment when diesel engine technology hadn’t quite caught up with the on-farm requirement, and a governmental lust for a lower-tax tractor fuel that couldn’t be illicitly used in a car.

TVO is a fuel with a low octane rating, where the octane rating is the resistance to ignition through compression alone. In chemical terms octane rating a product of how many volatile aromatic hydrocarbons are in the fuel, and to illustrate it your petrol/gasoline has an octane rating in the high 90s, diesel fuel has one close to zero, and TVO has a figure in the 50s. In practice this was achieved at the refinery by taking paraffin, or kerosene for Americans, a heavier fraction than petrol/gasoline, and adding some of those aromatic hydrocarbons to it. The result was a fuel on which a standard car engine wouldn’t run, but which would run on a specially low-compression engine with a normal spark ignition. This made it the perfect tax exempt fuel for farmers because it could only be used in tractors equipped with these engines, and thus in the years after WW2 a significant proportion of those Fergies and other tractors were equipped to run on it. Continue reading “Retrotechtacular: TVO” →

You Can Now Jailbreak A PS4 With An LG TV

May 16, 2024 by 12 Comments

You might think that jailbreaking a PS4 to run unsigned code is a complicated process that takes fancy tools and lots of work. While developing said jailbreaks was naturally no mean feat, thankfully they’re far easier for the end user to perform. These days, all you need is an LG TV.

Of course, you can’t just use any LG TV. You’ll need a modern LG webOS smart TV, and you’ll need to jailbreak it before it can in turn be used to modify your PS4. Once that’s done, though, you can install the PPLGPwn tool for jailbreaking PS4s. It’s based on the PPPwn exploit released by [TheFlow], which was then optimized by [xfangxfang] and implemented for LG Smart TVs by [zauceee]. Once installed, you just need to hook up your PS4 to the TV via the Ethernet port. Then, with the exploit running on the TV, telling the PS4 to set up the LAN via PPPoE will be enough to complete the jailbreak.

There are other ways to jailbreak a PS4 that don’t involve the use of a specific television. Nonetheless, it’s neat to see the hack done in such an amusing way.

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Your Smart TV Does 4K, Surround Sound, Denial-of-service…

April 23, 2024 by 53 Comments

Any reader who has bought a TV in recent years will know that it’s now almost impossible to buy one that’s just a TV. Instead they are all “smart” TVs, with an on-board computer running a custom OS with a pile of streaming apps installed. It fits an age in which linear broadcast TV is looking increasingly archaic, but it brings with it a host of new challenges.

Normally you’d expect us to launch into a story of privacy invasion from a TV manufacturer at this point, but instead we’ve got [Priscilla]’s experience, in which her HiSense Android TV executed a denial of service on the computers on her network.

The root of the problem appears to be the TV running continuous network discovery attempts using random UUIDs, which when happening every few minutes for a year or more, overloads the key caches on other networked machines. The PC which brought the problem to light was a Windows machine, which leaves us sincerely hoping that our Linux boxen might be immune.

It’s fair to place this story more under the heading of bugs than of malicious intent, but even so it’s something that should never have made it to production. The linked story advises nobody to buy a HiSense TV, but to that we’d have to doubt that other manufactures wouldn’t be similarly affected.

Header: William Hook, CC-BY-SA 2.0.

Thanks [Concretedog] for the tip.

This Week In Security: BatBadBut, DLink, And Your TV Too

April 12, 2024 by 23 Comments

So first up, we have BatBadBut, a pun based on the vulnerability being “about batch files and bad, but not the worst.” It’s a weird interaction between how Windows uses cmd.exe to execute batch files and how argument splitting and character escaping normally works. And what is apparently a documentation flaw in the Windows API.

When starting a process, even on Windows, the new executable is handed a set of arguments to parse. In Linux and friends, that is a pre-split list of arguments, the argv array. On Windows, it’s a single string, left up to the program to handle. The convention is to follow the same behavior as Linux, but the cmd.exe binary is a bit different. It uses the carrot ^ symbol instead of the backslash \ to escape special symbols, among other differences. The Rust devs took a look and decided that there are some cases where a given string just can’t be made safe for cmd.exe, and opted to just throw an error when a string met this criteria.

And that brings us to the big questions. Who’s fault is it, and how bad is it? I think there’s some shared blame here. The Microsoft documentation on CreateProcess() strongly suggests that it won’t execute a batch file without cmd.exe being explicitly called. On the other hand, This is established behavior, and scripting languages on Windows have to play the game by Microsoft’s rules. And the possible problem space is fairly narrow: Calling a batch file with untrusted arguments.

Almost all of the languages with this quirk have either released patches or documentation updates about the issue. There is a notable outlier, as the Java language will not receive a fix, not deeming it a vulnerability. It’s rather ironic, given that Java is probably the most likely language to actually find this problem in the wild. Continue reading “This Week In Security: BatBadBut, DLink, And Your TV Too” →

Inside A Hisense TV Repair Attempt

April 6, 2024 by 18 Comments

Many of us misspent our youth fixing televisions. But fixing a 1970s TV is a lot different than today — the parts were big and tubes were made to be replaced. Have you torn into a big flat screen lately? It is a different world, as [The Fixologist] shows us in the video below.

The TV in question was rescued from a neighbor who was about to throw it away. If you are like us, you’ll watch the first few minutes and see it powers up, but the screen is very dark. Back light problem, right? No problem. But it turned out to be more than we thought.

Honestly, we assumed it might be the power supply, and we would have put a power supply on the LED leads to test that first. That would have been smart because taking the panel off to reveal the LEDs was very difficult! There were two bad LEDs, though, so in the end you’d have had to do it anyway.

We were disappointed that after fixing the LED, he cracked the LCD panel during the reinstallation. So, in the end, this was more of a teardown video and not a repair video. He seemed to think a lot of the tape in the unit was to thwart repairs. That could be, but we wondered if it made manufacturing the TV easier which, after all, is mostly what they care about.

This isn’t the first time we’ve heard people tearing into a TV and wondering if the factory was against them. We’ve considered it, but we are pretty sure it isn’t the case.

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The Long Strange Trip To US Color TV

March 21, 2024 by 47 Comments

We are always fascinated when someone can take something and extend it in a clever way without changing the original thing. In the computer world, that’s old hat. New computers improve, but can usually run old software. In the real world, the addition of stereo to phonograph records and color to photography come to mind.

But there are few stories as strange or wide-ranging as the path to provide color TV. And it had to be done in a way that a color set could still get a black and white picture and black and white sets could still watch a color signal without color. You’d think there would be a “big bang” moment where color TV burst on the scene — no pun involving color burst intended. But there wasn’t. Instead, there was a long, twisted path with many competing interests and ideas to go from a world in black and white to one tinted with color phosphor.

Background

In 1928, Science and Invention magazine had plans for building a mechanical TV (although not color)

It is hard to imagine, but John Logie Baird transmitted color images as early as 1928 using a mechanical scanner. Bell Labs had a demonstration system, also mechanical, in 1929. Baird broadcast using his system in 1938. Even earlier, around 1900, there were attempts to create mechanical color image systems. Those systems were fickle or impractical, though.

Electronic scanning was the answer, but World War II froze most consumer electronics development. Baird showed an electronic color system in late 1944. However, it would be 1953 before NTSC (the National Television System Committee) adopted the standard color TV signal for the United States. It would be almost 20 years later before SECAM and PAL were standardized in other parts of the world.

Of course, these are all analog standards. The world’s gone digital now, but for nearly 50 years, analog color TV was the way people consumed TV in their homes. By 1941, NTSC produced a standard in the United States, but not for color TV. TV adoption didn’t really take off until after the war. But by 1950, the US had some 6 million TV sets.

This was both a plus — a large market — and a negative. No one wanted to obsolete those 6 million sets. Well, at least, the government regulators and consumers didn’t. But most color systems would be incompatible with those existing black and white sets. Continue reading “The Long Strange Trip To US Color TV” →

Your Cat Needs Its Own TV

March 10, 2024 by 21 Comments

Cats are wonderful creatures to have around, and they provide us with hours of entertainment. So why not do a little something to entertain them in return? That’s exactly what [Becky Stern] did by making a cat TV that shows YouTube videos of birds and other cat-approved content. Not all cats seem to care about TV, but [Becky]’s cat Benchley really gets into it.

As you may have guessed, this is a fairly simple build, consisting largely of a Raspberry Pi, a speaker, and a screen — a 5″ HDMI LCD display to be exact. Seems like a nice size for cats. After getting the cat-puter up and running, [Becky] set about designing a 3D-printed enclosure to turn it into a TV. The first draft looked great in marble-effect filament, but lacked breathing holes for the Pi, so the final version has a nice honeycomb pattern that is too small for curious cat paws to fit through.

What their paws can do is accidentally pause the video via the touch screen, so [Becky] swapped the USB cable for a charge-only to prevent this. Be sure to check out the build video after the break, because there is plenty of cat cuteness to be had. [Benchley] was so into it that he went looking around back for cats and squirrels inside the box.

Would you rather not encourage your cats to lie about the house watching TV all day? Make them play piano for their dinner.

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