This allows us to use SNI for actual host (e.g. routing) information. We
don't have the client cert yet so we can't look at that, so this
provides a way for us to convey the information needed to look up that
session's TLS stack.
Using SNI for hosts means we also run into the fact that we don't have
automatic agreement in terms of SANs. So when generating the certs we
now also pass worker address information to the function to be encoded
in the cert.
Finally, there is a change in how the websocket dialing happens, because
http.RoundTripper tries to be too clever for its own good and overwrites
NextProtos on a whim.
This stores worker connection nonces within the database to ensure
uniqueness of connections. Prior the connection required any attacker to
be able to decrypt the incoming encrypted authentication message in
order to replay (and if the attacker has access to the KMS you have
bigger problems), but with this change even if an attacker does have
access to the KMS key, they cannot reuse the same message. (If they're
able to encrypt against the KMS key, they can still act as a worker with
a new message, so this only really helps if they only have decryption
capabilities.)
* Encrypt tokens on the way out and decrypt on the way in
This isn't a security feature related to tokens specifically; it's so
that we can discard cryptographically bad tokens before we ever hit the
DB. This way we can't pass through a DDoS to the database due to
fetching obviously invalid token values.
I'm using base58 to encode the resulting value as there aren't great
base62 options, and allowing base64 / and + values can hamper usability
by creating copying/highlighting breaks.
Jeff Mitchell
Michael GaffneyandJeff Mitchell
Todd Knight