Unique<T> is unsafe

Someone created this PR on github: https://github.com/redox-os/kernel/pull/94

The description is repeated here in case the PR is lost.

Hi, I found a memory-safety/soundness issue in this crate while scanning Rust code for potential vulnerabilities. This PR contains a fix for the issue. Issue Description

Unique unconditionally implements Sync. This allows users to create data races on T: !Sync. Such data races can lead to undefined behavior.

kernel/src/common/unique.rs, Lines 15 to 16 in 7269f9c6

unsafe impl<T> Send for Unique<T> {} 
unsafe impl<T> Sync for Unique<T> {}

added correctness easy security labels

changed the description

4lDO2 recommends removing Unique

Having looked at the actual API, this issue is a false positive. It's true that Unique is unsafe, but it's not unsound. In particular, the only way to access the inner pointee from a shared reference, is to access it as a regular pointer, which can't be done from safe Rust.

Unique should be removed though, as it's only currently used for AlignedBox.

closed