1. The current implementation of the SSH command is heavily tied to the
assumptions of OTP/dynamic key types. The SSH CA backend is
fundamentally a different approach to login and authentication. As a
result, there was some restructuring of existing methods to share more
code and state.
2. Each authentication method (ca, otp, dynamic) are now fully-contained
in their own handle* function.
3. -mode and -role are going to be required for SSH CA, and I don't
think the magical UX (and overhead) of guessing them is a good UX. It's
confusing as to which role and how Vault guesses. We can reduce 66% of
the API calls and add more declaration to the CLI by making -mode and
-role required. This commit adds warnings for that deprecation, but
these values are both required for CA type authentication.
4. The principal and extensions are currently fixed, and I personally
believe that's good enough for the first pass at this. Until we
understand what configuration options users will want, I think we should
ship with all the local extensions enabled. Users who don't want that
can generate the key themselves directly (current behavior) or submit
PRs to make the map of extensions customizable.
5. Host key checking for the CA backend is not currently implemented.
It's not strictly required at setup, so I need to think about whether it
belongs here.
This is not ready for merge, but it's ready for early review.
From the sshpass manpage:
> The -p option should be considered the least secure of all of sshpass's options. All system users can see the password in the command line with a simple "ps" command. Sshpass makes a minimal attempt to hide the password, but such attempts are doomed to create race conditions without actually solving the problem. Users of sshpass are encouraged to use one of the other password passing techniques, which are all more secure.
This PR changes the sshpass behavior to execute a subprocess with the
SSHPASS envvar (which is generally regarded as more secure) than using
the -p option.
* Normalize "X arguments expected" messages
* Use "Vault" when referring to the product and "vault" when referring to an instance of the product
* Various minor tweaks to improve readability and/or provide clarity
