expose SSL_export_keying_material via Node API (e.g. like SSL_get_shared_sigalgs)

[simllll]

Is your feature request related to a problem? Please describe.
I'm trying to generate a check sum that is based on the keying material (https://stackoverflow.com/questions/60232165/ssl-export-keying-material-in-node-js). Right now node has no method to call this function, or any other way of retrieving this information.

Describe the solution you'd like
Expose an api like the GetSharedSigalgs that offers a way to access the native SSL export keying material method.
see https://nodejs.org/api/tls.html#tls_tlssocket_getsharedsigalgs
for the keying material method see https://www.openssl.org/docs/man1.0.2/man3/SSL_export_keying_material.html

Describe alternatives you've considered
I tried to get this kind of information via 'keylog' event, but this is never emitted in my scenario. I also believe (couldn't verify though), that this is something else than the exporting keying material function offers, due to the fact that I cannot provide any label to "keylog" which is mandatory for the keying material method.

Subsystem: tls (tls.TLSSocket)

[jasnell]

/cc @nodejs/crypto

[sam-github]

keylog is delivered from https://www.openssl.org/docs/man1.1.1/man3/SSL_CTX_set_keylog_callback.html, but if that isn't what you need exposing this new API seems reasonable.

Care to take a shot at it? It seems you've already found the code it would be similar to.

[bnoordhuis]

There's a mildly slippery slope here in that SSL_export_keying_material_early() is probably also necessary for TLSv1.3 - although that's only relevant with 0-RTT and Node doesn't really support that right now.

(I say "not really" because I think a tls.Server instance still accepts it but then proceeds to terminate the connection. We should probably have a test for that so we'll be aware of behavior changes.)

[simllll]

@sam-github I tried my best, do you mind taking a look at it? :-) #31814