rust-openssl has incorrect bounds assertion in aes key wrap

Summary

aes::unwrap_key() has an incorrect bounds assertion on the out buffer size, which can lead to out-of-bounds write.

Details

aes::unwrap_key() contains an incorrect assertion: it checks that out.len() + 8 <= in_.len(), but this condition is reversed. The intended invariant is out.len() >= in_.len() - 8, ensuring the output buffer is large enough.

Because of the inverted check, the function only accepts buffers at or below the minimum required size and rejects larger ones. If a smaller buffer is provided the function will write past the end of out by in_.len() - 8 - out.len() bytes, causing an out-of-bounds write from a safe public function.

Impact

Vulnerable applications using AES keywrap and allowing attacker controlled buffer sizes could have an attacker trigger an out-of-bounds write.