Recent submissions

Comment · 8 days ago
How long would it have taken you to root, debloat, and code a new UI for your TV?
Comment · 1 month ago
Comment · 2 months ago
侍
Comment · 2 months ago
Why didn’t they?
Comment · 5 months ago
Do you have any evidence this is actually happening to good faith security researchers?

There are many examples of Microsoft and other large corporations treating security researchers well. Microsoft hosts BlueHat, where they invite external parties to talk about their findings. They thank researchers monthly who do contribute reports to MSRC. As I recall, they treated bunnie well, and I think they also treated “hoodie” (the original Xbox 360 hacker) well as well.

Comment · 7 months ago
Can’t find the pdf, but it’s all related to the zentool stuff:

https://github.com/google/security-research/blob/master/pocs...

Tavis spells it out there pretty quickly:

“ The simplest instructions (add, sub, mov, etc) are all implemented in hardware. The more complicated instructions like rdrand, fpatan and cmpxchg are microcoded. You can think of them as a bit like calling into a library of functions written in that RISC-like code.”

Comment · 7 months ago
I saw the paper from Google last year and thought something in it aligned with not everything running through the microcode engine, though I could be wrong.
Comment · 7 months ago
I believe only some parts of Jazelle are handled in hardware, though I don’t know if anybody has got their hands on any of the bits of the software side. I do know there’s documentation on handling unimplemented instructions.

I don’t know how I feel about micro-ops being executed in hardware - I mostly agree, but also, microcode updates exist…

Comment · 7 months ago
Most of the time. But sometimes, no. See ATL thunk emulation (last I checked, still alive in the windows kernel) and ntvdm handling of the BOP pseudoinstruction.

See also: Jazelle DBX.

Hell, on modern x86 processors, many “native” instructions are actually a series of micro-ops for a mostly undocumented and mostly poorly understood microcode architecture that differs from the natively documented instruction set.

It’s turtles all the way down.

Comment · 8 months ago
I agree there’s a big divide. I think I’m also team “let people do things they enjoy.”

I like using computers to solve problems. I’m more interested in the problem being solved than the journey most of the time, though I’ve also been on some lovely journeys. Sometimes that means I write a tool all by myself. Sometimes it means I download an existing open source tool. And sometimes it means I delegate the creation to an AI model.

Comment · 8 months ago
Can you look at code today and predict what assembly a compiler will output to some high degree of accuracy? Do you avoid certain classes of compiler optimization so you can more accurately predict compiler output? I recall a time where many compilers would remove a bzero() operation in situations where you’re trying to zero out a buffer that had sensitive data in it - it’s why we have APIs like https://github.com/MicrosoftDocs/win32/blob/docs/desktop-src.... I ran into a huge performance regression because I didn’t have all the edges of named return value optimization in mind when I refactored some code.

There’s ambiguity in the x86 specification, such that you can execute a single instruction and get different results in intel vs amd. See the rcpss instruction, for example.

I get that LLMs are categorically different, and they’re absolutely not as reliable as compilers are, but compilers are also not as reliable as compilers seem. And even less predictable IMO.

Comment · 8 months ago
I agree with this, but I’m also curious: what would have to change before that advice is as sound as “write a little bit of assembly by hand” or the even more ridiculous “just write the raw bytes for the program in a hex editor?”
Comment · 10 months ago
Yea, but Galen’s a beast so it might actually happen.
Comment · 1 year ago
If I asked a human assistant to do this and it came back with that level of research, I’d be pretty disappointed.
Comment · 1 year ago
This doesn’t seem true. Doesn’t LSASS cache credentials for 30 days?

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