StarDreamer @ stardreamer @lemmy.blahaj.zone

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2 yr. ago

Leaks also show why the Titanic sank

I'm not familiar with the topic but couldn't they cut straight to the source and directly contact Corning? Or alternatively, one of those Chinese high end OLED knock offs? I've heard they're basically less than 1 generation apart in terms of quality.

edit: alternatively, I assume all cables/connectors are standard. What's preventing Jim next door from starting a group buy to manufacture replacement OLED screens/upgrade kits?

Funny how a game about fearing the unknown is being hated on by a group that fears the (relatively) unknown.

How the heck do you end up peeling off 1g of edible potato?

ELI5, or ELIAFYCSS (Explain like I'm a first year CS student): modern x86 CPUs have lots of optimized instructions for specific functionality. One of these is "vector instructions", where the instruction is optimized for running the same function (e.g. matrix multiply add) on lots of data (e.g. 32 rows or 512 rows). These instructions were slowly added over time, so there are multiple "sets" of vector instructions like MMX, AVX, AVX-2, AVX-512, AMX...

While the names all sound different, the way how all these vector instructions work is similar: they store internal state in hidden registers that the programmer cannot access. So to the user (application programmer or compiler designer) it looks like a simple function that does what you need without having to micromanage registers. Neat, right?

Well, problem is somewhere along the lines someone found a bug: when using instructions from the AVX-2/AVX-512 sets, if you combine it with an incorrect ordering of branch instructions (aka JX, basically the if/else of assembly) you get to see what's inside these hidden registers, including from different programs. Oops. So Charlie's "Up, Up, Down, Down, Left, Right, Left, Right, B, B, A, A" using AVX/JX allows him to see what Alice's "encrypt this zip file with this password" program is doing. Uh oh.

So, that sounds bad. But lets take a step back: how bad would this affect existing consumer devices (e.g. Non-Xeon, non-Epyc CPUs)?

Well good news: AVX-512 is not available on most Intel/AMD consumer CPUs until recently (13th gen/zen 4, and zen 4 isn't affected). So 1) your CPU most likely doesn't support it and 2) even if your CPU supports it most pre-compiled programs won't use it because the program would crash on everyone else's computer that doesn't have AVX-512. AVX-512 is a non-issue unless you're running Finite Element Analysis programs (LS-DYNA) for fun.

AVX-2 has a similar problem: while released in 2013, some low end CPUs (e.g. Intel Atom) didn't have them for a long time (this year I think?). So most compiled programs wouldn't compile with AVX-2 enabled. This means whatever game you are running now, you probably won't see a performance drop after patching since your computer/program was never using the optimized vector instructions in the first place.

So, the affect on consumer devices is minimal. But what do you need to do to ensure that your PC is secure?

Three different ideas off the top of my head:

1. BIOS update. The CPU has a some low level firmware code called microcode which is included in the BIOS. The new patched version adds additional checks to ensure no data is leaked.
2. Update the microcode package in Linux. The microcode can also be loaded from the OS. If you have an up-to-date version of Intel-microcode here this would achieve the same as (1)
3. Re-compile everything without AVX-2/AVX-512. If you're running something like Gentoo, you can simply tell GCC to not use AVX-2/AVX-512 regardless of whether your CPU supports it. As mentioned earlier the performance loss is probably going to be fine unless you're doing some serious math (FEA/AI/etc) on your machine.

I would say you'll be fine. Most games don't compile with avx-2 anyways since it'll crash if you run it on something that doesn't have them (which is a lot of CPUs) and AVX-512 is straight up only available on Xeons, Epyc and zen 4. Nobody is going to use that for consumer software.

The only game I can think of using AVX is a Skyrim mod for realistic physics, where the author provided binaries for AVX-2/AVX-512. So it won't affect most compiled applications much since you need to compile with it first (which almost nobody does).

It's the AVX-2/AVX-512 instructions that have issues. In most cases unless you're running a server CPU (or extremely recent consumer CPU) you'll be fine.

Scary for HPC/AI? Yes. For most people? Not really.

Of course I don't carry 5 external drives with me all the time, that would be ridiculous.

I carry the whole HBA.

1. ChatGPT gives bad command, system fails to boot
2. Drops into emergency shell
3. Ask ChatGPT how to fix fstab from emergency shell
4. Goto 1), rinse and repeat

You can also replace ChatGPT with Devin and achieve the same results

Your mileage may vary depending on the quality of your Devin

So does openbox /s

CrowdSec has completely replaced fail2ban for me. It's a bit harder to setup but it's way more flexible with bans/statistics/etc. Also uses less ram.

It's also fun to watch the ban counter go up for things that I would never think about configuring on fail2ban, such as nginx CVEs.

Edit: fixed url. Oops!

that one NetBSD user bursts into flames