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Fast memory vulnerabilities, written in 100% safe Rust (github.com)

submitted 8 months ago by [email protected] to c/[email protected]

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[–] [email protected] 23 points 8 months ago (2 children)

Giving off a lot of mixed signals with this one, lol 😅

[–] [email protected] 10 points 8 months ago

My thoughts exactly!

Now, with cve-rs, you can corrupt your program's memory without corrupting your program's memory.

[–] [email protected] 47 points 8 months ago* (last edited 8 months ago) (1 children)

It's utilizing an obscure bug in the Rust compiler that unfortunately lets you circumvent the safety guarantees in order to produce undefined behavior - it's mostly just a joke though, you will not run into the bug in normal code

[–] [email protected] 4 points 8 months ago (1 children)

Thanks for clarifying. Do you know what the bug is? I gathering it's something to do with enums and boxing to enable a "safe" transmute, but couldn't make sense of the code.

Scary compiler edge cases with value-type enums aren't surprising though. Trying to implement that feature with memory safety and high performance sounds like a nightmare.

[–] [email protected] 14 points 8 months ago

It's essentially this issue https://github.com/rust-lang/rust/issues/25860

The code used to exploit the bug in this library is here: https://github.com/Speykious/cve-rs/blob/main/src/lifetime_expansion.rs

As far as I understand, the bug basically makes it so you can trick Rust into thinking any lifetime is actually 'static. From that, you can do all kinds of bad stuff.