Got runtime error when getting keying_material

[zhoucengchao]

Hi,

I am testing the fantastic sslkeylog module. I am able to get things like clientRandom, serverRandom, but not the keying_material with an runtime error. I think the provided parameters may have problem, but I am not sure what need to provide.

sslkeylog.export_keying_material(ssl_sock,256,'key expansion')
Traceback (most recent call last):
File "", line 1, in
File "/home/labadmin/.local/lib/python3.8/site-packages/sslkeylog.py", line 121, in export_keying_material
return _sslkeylog.export_keying_material(sock, length, label, context)
RuntimeError: SSL_export_keying_material() failed

Any ideas?

[segevfiner]

OpenSSL doesn't allow using certain reserved labels with SSL_export_keying_material: https://github.com/openssl/openssl/blob/cac250755efd0c40cc6127a0e4baceb8d226c7e3/ssl/t1_enc.c#L697-L699