TLS curve/group name logging for Ticket Resumption

[bneradt]

This applies to the cqssu (curve) and cqssg (group name) TLS log fields.

This does two things:

• Updates server session caching logic to provide the TLS group name on
  resumption.
• Updates the logging of the curve and group name for ticket resumption
  logic so that the TLS curve and group names are properly retrieved
  from the SSL object. For ticket resumption, there is no curve/group
  name stored to retrieve. It is properly retrieved from the SSL object.

Before this change: (1) the SSL group was always retrieved from the SSL
object when it should have been retrieved from the server session cache
ex_data for session cache resumption and (2) the curve value for cqssu
was alway "-" for TLS ticket resumption because there was no cached
value to retrieve like there is with server session caching.

Fixes: #12398

[maskit]

It doesn't seem like we need to add a new variable to record a group name. Although both OpenSSL and BoringSSL have different APIs for curve and group, the getters are actually just aliases unlike the setters for context objects. We should be able to use the same variable for both curve and group.

TLSBasicSupport::get_tls_group which was added by #12261 is probably unnecessary. I don't know why the previous code doesn't work for group, but the function to get curve/group id is identical.

$ git grep SSL_get_shared_curve include/
include/openssl/ssl.h.in:# define SSL_get_shared_curve          SSL_get_shared_group

Also, SSL_get0_group_name is only available on OpenSSL 3.2 or later. I see the ifdef and get_tls_group probably returns nullptr on OpenSSL 3.0, but I'd be surprised if there's no way to achieve it on 3.0.

[bneradt]

Also, SSL_get0_group_name is only available on OpenSSL 3.2 or later. I see the ifdef and get_tls_group probably returns nullptr on OpenSSL 3.0, but I'd be surprised if there's no way to achieve it on 3.0.

This is a great point. I updated the patch for openssl 3.0 and 3.1 via SSL_get_negotiated_group. Since 3.2, the docs say to prefer the new SSL_get0_group_name, but for 3.0 and 3.1 we can use the former. See:

#elif HAVE_SSL_GET_NEGOTIATED_GROUP                    // OpenSSL 3.0/3.1
  int group_nid = SSL_get_negotiated_group(ssl);
  if (group_nid != NID_undef) {
    char const *group_name = OBJ_nid2sn(group_nid);
    return group_name != nullptr ? std::string_view(group_name) : "";
  }
  return "";