This is a follow-up to our initial work[0] to address RFC-5952 §4 conformance for IPv6 addresses in Vault. The initial pass focused on the vault server configuration and start-up routines. This follow-up focuses on Agent and Proxy, with a few minor improvements for server.
The approach generally mirrors the server implementation but also adds support for normalization with CLI configuration overrides.
One aspect we do not normalize currently is Agent/Proxy client creation to the Vault server with credentials taken from environment variables, as it would require larger changes to the `api` module. In practice this ought to be fine for the majority of cases.
[0]: https://github.com/hashicorp/vault/pull/29228
USGv6[0] requires implementing §4.1.1 of the NISTv6-r1 profile[1] for
IPv6-Only capabilities. This section requires that whenever Vault
displays IPv6 addresses (including CLI output, Web UI, logs, etc.) that
_all_ IPv6 addresses must conform to RFC-5952 §4 text representation
recommendations[2].
These recommendations do not prevent us from accepting RFC-4241[3] IPv6
addresses, however, whenever these same addresses are displayed they
must conform to the strict RFC-5952 §4 guidelines.
This PR implements handling of IPv6 address conformance in our
`vault server` routine. We handle conformance normalization for all
server, http_proxy, listener, seal, storage and telemetry
configuration where an input could contain an IPv6 address, whether
configured via an HCL file or via corresponding environment variables.
The approach I've taken is to handle conformance normalization at
parse time to ensure that all log output and subsequent usage
inside of Vaults various subsystems always reference a conformant
address, that way we don't need concern ourselves with conformance
later. This approach ought to be backwards compatible to prior loose
address configuration requirements, with the understanding that
going forward all IPv6 representation will be strict regardless of
what has been configured.
In many cases I've updated our various parser functions to call the
new `configutil.NormalizeAddr()` to apply conformance normalization.
Others required no changes because they rely on standard library URL
string output, which always displays IPv6 URLs in a conformant way.
Not included in this changes is any other vault exec mode other than
server. Client, operator commands, agent mode, proxy mode, etc. will
be included in subsequent changes if necessary.
[0]: https://www.nist.gov/publications/usgv6-profile
[1]: https://www.nist.gov/publications/nist-ipv6-profile
[2]: https://www.rfc-editor.org/rfc/rfc5952.html#section-4
[3]: https://www.rfc-editor.org/rfc/rfc4291
Signed-off-by: Ryan Cragun <me@ryan.ec>
