NIF’s Laser Fusion Experiment’s Energy Gain Passes Peer Review

February 9, 2024 by Maya Posch 53 Comments

Back in December of 2022, a team of researchers at the USA’s National Ignition Facility (NIF) announced that they had exceeded ‘scientific breakeven’ with their laser-based inertial confinement fusion (ICF) system. Their work has now been peer-reviewed and passed scrutiny, confirming that the energy put into fusing a small amount of deuterium-tritium fuel resulted in a net gain (Q) of 1.5.

Laser Bay 2, one of NIF's two laser bays — Laser Bay 2 at the NIF.

The key take-away here of course remains that ICF is not a viable method of producing energy, as we detailed back in 2021 when we covered the 1.3 MJ yield announcement, and again in 2022 following the subject of this now completed peer review. The sheer amount of energy required to produce the laser energy targeting the fuel capsule and loss therein, as well as the energy required to manufacture each of these fuel capsules (Hohlraum) and sustaining a cycle make it a highly impractical proposition for anything except weapons research.

Despite this, it’s good to see that the NIF’s ICF research is bearing fruit, even if for energy production we should look towards magnetic confinement fusion (MCF), which includes the many tokamaks active today like Japan’s JT-60SE, as well as stellarators like Germany’s Wendelstein 7-X and other efforts to make MCF a major clean-energy source for the future.

This Week In Security: Broken Shims, LassPass, And Toothbrushes?

February 9, 2024 by Jonathan Bennett 8 Comments

Linux has a shim problem. Which naturally leads to a reasonable question: What’s a shim, and why do we need it? The answer: Making Linux work wit Secure Boot, and an unintended quirk of the GPLv3.

Secure Boot is the verification scheme in modern machines that guarantees that only a trusted OS can boot. When Secure Boot was first introduced, many Linux fans suggested it was little more than an attempt to keep Linux distros off of consumer’s machines. That fear seems to have been unwarranted, as Microsoft has dutifully kept the Linux Shim signed, so we can all run Linux distros on our Secure Boot machines.

So the shim. It’s essentially a first-stage bootloader, that can boot a signed GRUB2 or other target. You might ask, why can’t we just ask Microsoft to sign GRUB2 directly? And that’s where the GPLv3 comes in. That license has an “anti-tivoization” section, which specifies “Installation Information” as part of what must be provided as part of GPLv3 compliance. And Microsoft’s legal team understands that requirement to apply to even this signing process. And it would totally defeat the point of Secure Boot to release the keys, so no GPLv3 code gets signed. Instead, we get the shim.

Now that we understand the shim, let’s cover how it’s broken. The most serious vulnerability is a buffer overflow in the HTTP file transfer code. The buffer is allocated based on the size in the HTTP header, but a malicious HTTP server can set that value incorrectly, and the shim code would happily write the real HTTP contents past the end of that buffer, leading to arbitrary code execution. You might ask, why in the world does the shim have HTTP code in it at all? The simple answer is to support UEFI HTTP Boot, a replacement for PXE boot.

The good news is that this vulnerability can only be triggered when using HTTP boot, and only by connecting to a malicious server or via a man-in-the-middle attack. With this in mind, it’s odd that this vulnerability is rated a 9.8. Specifically, it seems incorrect that this bug is rated low complexity, or a general network attack vector. In Red Hat’s own write-up of the vulnerability, they argue that the exploitation is high complexity, and is only possible from an adjacent network. There were a handful of lesser vulnerabilities found, and these were all fixed with shim 15.8. Continue reading “This Week In Security: Broken Shims, LassPass, And Toothbrushes?” →

Flipped Bit Could Mark The End Of Voyager 1‘s Interstellar Mission

February 9, 2024 by Dan Maloney 95 Comments

Sometimes it’s hard to read the tea leaves of what’s going on with high-profile space missions. Weighted down as they are with the need to be careful with taxpayer money and having so much national prestige on the line, space agencies are usually pretty cagey about what’s going on up there. But when project managers talk about needing a “miracle” to continue a project, you know things have gotten serious.

And so things now sit with Voyager 1, humanity’s most distant scientific outpost, currently careening away from Mother Earth at 17 kilometers every second and unable to transmit useful scientific or engineering data back to us across nearly a light-day of space. The problem with the 46-year-old spacecraft cropped up back in November, when Voyager started sending gibberish back to Earth. NASA publicly discussed the problem in December, initially blaming it on the telemetry modulation unit (TMU) that packages data from the remaining operable scientific instruments along with engineering data for transmission back to Earth. It appeared at the time that the TMU was not properly communicating with the flight data system (FDS), the main flight computer aboard the spacecraft.

Since then, flight controllers have determined that the problem lies within the one remaining FDS on board (the backup FDS failed back in 1981), most likely thanks to a single bit of corrupted memory. The Deep Space Network is still receiving carrier signals from Voyager, meaning its 3.7-meter high-gain antenna is still pointing back at Earth, so that’s encouraging. But with the corrupt memory, they’ve got no engineering data from the spacecraft to confirm their hypothesis.

The team has tried rebooting the FDS, to no avail. They’re currently evaluating a plan to send commands to put the spacecraft into a flight mode last used during its planetary fly-bys, in the hope that will yield some clues about where the memory is corrupted, if indeed it is. But without a simulator to test the changes, and with most of the engineers who originally built the spacecraft long gone now, the team is treading very carefully.

Voyager 1 is long past warranty, of course, and with an unparalleled record of discovery, it doesn’t owe us anything at this point. But we’re not quite ready to see it slip into its long interstellar sleep, and we wish the team good luck while it works through the issue.

Power Supply Efficiency Measurements

February 9, 2024 by Al Williams 12 Comments

Even if you don’t have a Rohde Schwarz oscilloscope, you can still enjoy their recent video about using an oscilloscope to measure power supply efficiency. Of course, you don’t have to have a scope to do this. You can use a voltmeter and an ammeter, but it is very straightforward if you have a four-channel scope with a pair of current probes.

Of course, if you can measure the voltage and the current at the input, you can calculate the input power. Then again, most scopes these days can do the math for you. Then, you make the same measurement and calculation at the output. If you know the input and output power, you can calculate a percentage or many scopes can do it for you now.

Continue reading “Power Supply Efficiency Measurements” →