`ptrace::getregs` & `ptrace::getregset` may lead to UB of uninitialized data read about nix HOT 4 OPEN

It isn't UB because the data is half-uninitialized. After all the rust compiler doesn't know how much data is initialized by the OS, so it must assume that all is. But it certainly doesn't sound like the data in this case is a valid S::Regs. Would you be willing to file a PR to fix the bug? Without wanting to add full 32-bit support, it would be sufficient to simply return an error in that case.

from nix.

@asomers Thank you for your reply :)

I have sent a PR (#2448) to fix this.

However, I do think this is a UB. It's true that Rust compiler doesn't know how much data is initialized by the OS, and as a result, it is considered UB to read the uninitialized part, and that is what the read-buf RFC proposed to solve.

from nix.

Thanks for the report!

cc @hack3ric

I am curious if this problem exists on other targets? e.g., arm64.

from nix.

I am curious if this problem exists on other targets? e.g., arm64.

I have no arm64 machine, maybe someone could help testing this.

from nix.