tls: set client CA list based on the ca-dir() and ca-file() options

[alltilla]

Filling the certificate_authorities field of the certificate request, to help clients choose certs to use.

From https://www.ietf.org/rfc/rfc5246.txt 7.4.4:

certificate_authorities
A list of the distinguished names [X501] of acceptable
certificate_authorities, represented in DER-encoded format. These
distinguished names may specify a desired distinguished name for a
root CA or for a subordinate CA; thus, this message can be used to
describe known roots as well as a desired authorization space. If
the certificate_authorities list is empty, then the client MAY
send any certificate of the appropriate ClientCertificateType,
unless there is some external arrangement to the contrary.

Example:

source s_network {
  network(
    port(12345)
    transport(tls)
    tls(
      ca-dir("/etc/ssl/certs/")
      ca-file("/home/alltilla/repos/syslog-ng/build/install/ssl/ca.crt")
      key-file("/home/alltilla/repos/syslog-ng/build/install/ssl/server.key")
      cert-file("/home/alltilla/repos/syslog-ng/build/install/ssl/server.crt")
      peer-verify(required-trusted)
      ssl-options(no_tlsv13)
    )
  );
};

Signed-off-by: Attila Szakacs attila.szakacs@axoflow.com

[alltilla]

I know that this is yet another case, where sometimes the function is a NOOP, but it would be strange to see the preprocessor macros about the SSL functions being further away from the place they are actually called.

[alltilla]

I have observed, that in case of failure the X509_NAMEs were leaking. Added a fix for it.