Headline
GHSA-r24f-hg58-vfrw: unsafe-libyaml unaligned write of u64 on 32-bit and 16-bit platforms
Affected versions allocate memory using the alignment of usize and write data to it of type u64, without using core::ptr::write_unaligned. In platforms with sub-64bit alignment for usize (including wasm32 and x86) these writes are insufficiently aligned some of the time.
If using an ordinary optimized standard library, the bug exhibits Undefined Behavior so may or may not behave in any sensible way, depending on optimization settings and hardware and other things. If using a Rust standard library built with debug assertions enabled, the bug manifests deterministically in a crash (non-unwinding panic) saying “ptr::write requires that the pointer argument is aligned and non-null”.
No 64-bit platform is impacted by the bug.
The flaw was corrected by allocating with adequately high alignment on all platforms.
- GitHub Advisory Database
- GitHub Reviewed
- GHSA-r24f-hg58-vfrw
unsafe-libyaml unaligned write of u64 on 32-bit and 16-bit platforms
Moderate severity GitHub Reviewed Published Dec 21, 2023 to the GitHub Advisory Database • Updated Dec 21, 2023
Package
cargo unsafe-libyaml (Rust)
Affected versions
< 0.2.10
Affected versions allocate memory using the alignment of usize and write data to it of type u64, without using core::ptr::write_unaligned. In platforms with sub-64bit alignment for usize (including wasm32 and x86) these writes are insufficiently aligned some of the time.
If using an ordinary optimized standard library, the bug exhibits Undefined Behavior so may or may not behave in any sensible way, depending on optimization settings and hardware and other things. If using a Rust standard library built with debug assertions enabled, the bug manifests deterministically in a crash (non-unwinding panic) saying “ptr::write requires that the pointer argument is aligned and non-null”.
No 64-bit platform is impacted by the bug.
The flaw was corrected by allocating with adequately high alignment on all
platforms.
References
- dtolnay/unsafe-libyaml#21
- dtolnay/unsafe-libyaml@7755559
- https://rustsec.org/advisories/RUSTSEC-2023-0075.html
Published to the GitHub Advisory Database
Dec 21, 2023
Last updated
Dec 21, 2023