The ocsp-responder takes a path to a certificate file as one of
its config values. It uses this path as one of the inputs when
constructing its DBSource, the object responsible for querying
the database for pregenerated OCSP responses to fulfill requests.
However, this certificate file is not necessary to query the
database; rather, it only acts as a filter: OCSP requests whose
IssuerKeyHash do not match the hash of the loaded certificate are
rejected outright, without querying the DB. In addition, there is
currently only support for a single certificate file in the config.
This change adds support for multiple issuer certificate files in
the config, and refactors the pre-database filtering of bad OCSP
requests into a helper object dedicated solely to that purpose.
Fixes#5119
Integrates the cfssl/ocsp responder code directly into boulder. I've tried to
pare down the existing code to only the bits we actually use and have removed
some generic interfaces in places in favor of directly using our boulder
specific interfaces.
Fixes#4427.