This is much more complex than the TLS Extension/OCSP cases. We need to
first alter the certificate and remove the extension from it, before
extracting the tbscert. Furthermore, we need the key hash of the issuing
certificate to be able to validate the proof - which means that we need
a valid certificate chain.
Missing: documentation, nice integration so that we can just add a
script and use this in Bro.
This does not yet work for certificates, because this requires some
changing the ASN.1 structure before validation (we need to extract the
tbscert and remove the SCT extension before).
API will change in the future.
This commit add the table SSL::ct_logs to Bro. This table is populated
with information about the currently active certificate transparency
logs (data from Google). The data can, e.g., be used to identify which
Logs are being used in SCTs.
With this change, we also parse signed certificate timestamps from OCSP
replies. This introduces a common base class between the OCSP and X509
analyzer, which now share a bit of common code. The event for signed
certificate timestamps is raised by both and thus renamed do:
x509_ocsp_ext_signed_certificate_timestamp
This is a tiny bit evil because it uses parts of the SSL protocol
analyzer in the X.509 certificate parser. Which is the fault of the
protocol, which replicates the functionality.
There was a bug in the new parsing code, introduced in
708ede22c6 which parses validity times
incorrectly if they are before the year 2000. What happens in this case
is that the 2-digit year will be interpreted to be in the 21st century
(1999 will be parsed as 2099, e.g.).
