GHSA-HPPC-G8H3-XHP3 rust-openssl: Unchecked callback length in PSK/cookie trampolines leaks adjacent memory to peer

The FFI trampolines behind SslContextBuilder::setpskclientcallback, setpskservercallback, setcookiegeneratecb, and setstatelesscookiegeneratecb forwarded the user closure's returned usize directly to OpenSSL without checking it against the &mut u8 that was handed to the closure. This can lead to...