{"id":"RUSTSEC-2024-0429","summary":"Unsoundness in `Iterator` and `DoubleEndedIterator` impls for `glib::VariantStrIter`","details":"The `VariantStrIter::impl_get` function (called internally by implementations of the `Iterator` and `DoubleEndedIterator` traits for this type) was unsound, resulting in undefined behaviour.\n\nAn immutable reference `&p` to a `*mut libc::c_char` pointer initialized to `NULL` was passed as an argument to a C function that that mutates the pointer behind `&p` in-place (i.e. as an out-argument), which was unsound. After changes in recent versions of the Rust compiler, these unsound writes through `&p` now seem to be completely disregarded when building the `glib` crate with optimizations.\n\nThis subsequently caused all calls of `VariantStrIter::impl_get` to violate the safety requirements of the `std::ffi::CStr::from_ptr` function - which requires its argument to be a valid pointer to a C-style string - resulting in crashes due to `NULL` pointer dereferences.\n\nThis was fixed by passing the out-argument pointer explitly as `&mut p` instead of `&p`.\n\nThis issue has been present since this code was initially added in `glib` v0.15.0. The mismatch in mutability was likely missed (and not raised as an error by the compiler) because the C function wrapped by `VariantStrIter::impl_get` is variadic (`glib_sys::g_variant_get_child`), and the pointer in question is one of the variadic arguments.","aliases":["GHSA-wrw7-89jp-8q8g"],"modified":"2025-10-28T06:29:26.473225Z","published":"2024-03-30T12:00:00Z","database_specific":{"license":"CC0-1.0"},"references":[{"type":"PACKAGE","url":"https://crates.io/crates/glib"},{"type":"ADVISORY","url":"https://rustsec.org/advisories/RUSTSEC-2024-0429.html"},{"type":"WEB","url":"https://github.com/gtk-rs/gtk-rs-core/pull/1343"}],"affected":[{"package":{"name":"glib","ecosystem":"crates.io","purl":"pkg:cargo/glib"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0.15.0"},{"fixed":"0.20.0"}]}],"ecosystem_specific":{"affected_functions":null,"affects":{"arch":[],"functions":["glib::VariantStrIter::last","glib::VariantStrIter::next","glib::VariantStrIter::next_back","glib::VariantStrIter::nth","glib::VariantStrIter::nth_back"],"os":[]}},"database_specific":{"categories":[],"cvss":null,"informational":"unsound","source":"https://github.com/rustsec/advisory-db/blob/osv/crates/RUSTSEC-2024-0429.json"}}],"schema_version":"1.7.3"}