Comment by j4k0bfr

11 days ago

Took me a good couple minutes to wrap my head around. Man, what a nasty bug. I guess this specific use-case is rare. Time to see if any of the big libs are affected...

10 comments

j4k0bfr

coliveira 11 days ago

A nasty and rare bug can and will be exploited once it is found. The only thing necessary is for malicious actors to start adding this case in innocent looking code and there you have.

afdbcreid 11 days ago
That's a misunderstanding. This is not a security vulnerability and Rust explicitly does not defend from malicious programs, only from mistakes. This bug however is quite dangerous, because unlike many soundness bugs it seems plausible to hit by mistake.
- Liquid_Fire 11 days ago
  
  > it seems plausible to hit by mistake
  The report seems to claim the opposite:
  > Looking at the bug itself, it is also very likely that this unsoundness has not caused memory unsafety by accident. While it looks easy to trigger, to exploit this you need an intentionally malicious Drop implementation.
  
  4 replies →
- rstuart4133 10 days ago
  
  > This bug however is quite dangerous, because unlike many soundness bugs it seems plausible to hit by mistake.
  Possibly. I'm no rust expert, so I had the read the code slowly, building up a mental model of the types being used. For me, the effort that required is one of the more painful aspects of Rust.
  Nonetheless when I got to this line, I stopped reading:
  q.0 = Some(&l);
  Given the type declarations it's "obvious" it should not compile as it directly contradicts the types 'static lifetime. You don't deliberately write code that doesn't compile.
  I write lots of code that doesn't compile of course. It's perfectly safe because the compiler catches it. Right now, I feel like a climber at the top of a mountain who just discovered he forgot to attach his safety harness.
  Who knows. Maybe all of crates.io will compile with the fixed compiler, because this is a mistake humans or LLM's never make. We will see.
  
  2 replies →