impl From<Buffer> for Vec<u8> is unsound

[nox]

The returned vector is backed by freed memory, because slice is dropped at the end of the function.

[sagebind]

Yep I see the problem; good catch!

[Shnatsel]

This looks like a use-after-free bug, which is typically exploitable. Please file a security advisory at https://github.com/RustSec/advisory-db

I understand this has been fixed over a year ago, but please do it anyway for the sake of people who haven't updated their dependencies in a while.

[sagebind]

@Shnatsel Sure thing, will do.