advisory-db/crates/self_cell/RUSTSEC-2023-0070.md

[advisory]
id = "RUSTSEC-2023-0070"
package = "self_cell"
date = "2023-11-10"
url = "https://github.com/Voultapher/self_cell/issues/49"
categories = []
keywords = ["unsound", "self_cell", "self-referential"]
aliases = ["GHSA-48m6-wm5p-rr6h"]

[versions]
patched = [">= 0.10.3, < 1.0.0", ">= 1.0.2"]

Insufficient covariance check makes self_cell unsound

All public versions prior to 1.02 used an insufficient check to ensure that users correctly marked the dependent type as either covariant or not_covariant. This allowed users to mark a dependent as covariant even though its type was not covariant but invariant, for certain invariant types involving trait object lifetimes. One example for such a dependent type is type Dependent<'a> = RefCell<Box<dyn fmt::Display + 'a>>. Such a type allowed unsound usage in purely safe user code that leads to undefined behavior. The patched versions now produce a compile time error if such a type is marked as covariant.