This commits dds 3 separate, but very related features:
1. Automated server identity management
How do you know you're connecting to the server you think you are? How do you know the server connecting to you is the server instance you think it is? Mutually-authenticated TLS (mTLS) answers both of these questions. Using TLS to authenticate requires a public/private key pair (and the peer must trust the certificate you present to it).
Fortunately, Caddy is really good at managing certificates by now. We tap into that power to make it possible for Caddy to obtain and renew its own identity credentials, or in other words, a certificate that can be used for both server verification when clients connect to it, and client verification when it connects to other servers. Its associated private key is essentially its identity, and TLS takes care of possession proofs.
This configuration is simply a list of identifiers and an optional list of custom certificate issuers. Identifiers are things like IP addresses or DNS names that can be used to access the Caddy instance. The default issuers are ZeroSSL and Let's Encrypt, but these are public CAs, so they won't issue certs for private identifiers. Caddy will simply manage credentials for these, which other parts of Caddy can use, for example: remote administration or dynamic config loading (described below).
2. Remote administration over secure connection
This feature adds generic remote admin functionality that is safe to expose on a public interface.
- The "remote" (or "secure") endpoint is optional. It does not affect the standard/local/plaintext endpoint.
- It's the same as the [API endpoint on localhost:2019](https://caddyserver.com/docs/api), but over TLS.
- TLS cannot be disabled on this endpoint.
- TLS mutual auth is required, and cannot be disabled.
- The server's certificate _must_ be obtained and renewed via automated means, such as ACME. It cannot be manually loaded.
- The TLS server takes care of verifying the client.
- The admin handler takes care of application-layer permissions (methods and paths that each client is allowed to use).\
- Sensible defaults are still WIP.
- Config fields subject to change/renaming.
3. Dyanmic config loading at startup
Since this feature was planned in tandem with remote admin, and depends on its changes, I am combining them into one PR.
Dynamic config loading is where you tell Caddy how to load its config, and then it loads and runs that. First, it will load the config you give it (and persist that so it can be optionally resumed later). Then, it will try pulling its _actual_ config using the module you've specified (dynamically loaded configs are _not_ persisted to storage, since resuming them doesn't make sense).
This PR comes with a standard config loader module called `caddy.config_loaders.http`.
Caddyfile config for all of this can probably be added later.
COMMITS:
* admin: Secure socket for remote management
Functional, but still WIP.
Optional secure socket for the admin endpoint is designed
for remote management, i.e. to be exposed on a public
port. It enforces TLS mutual authentication which cannot
be disabled. The default port for this is :2021. The server
certificate cannot be specified manually, it MUST be
obtained from a certificate issuer (i.e. ACME).
More polish and sensible defaults are still in development.
Also cleaned up and consolidated the code related to
quitting the process.
* Happy lint
* Implement dynamic config loading; HTTP config loader module
This allows Caddy to load a dynamic config when it starts.
Dynamically-loaded configs are intentionally not persisted to storage.
Includes an implementation of the standard config loader, HTTPLoader.
Can be used to download configs over HTTP(S).
* Refactor and cleanup; prevent recursive config pulls
Identity management is now separated from remote administration.
There is no need to enable remote administration if all you want is identity
management, but you will need to configure identity management
if you want remote administration.
* Fix lint warnings
* Rename identities->identifiers for consistency
* caddyfile: Introduce basic linting and fmt check
This will help encourage people to keep their Caddyfiles tidy.
* Remove unrelated tests
I am not sure that testing the output of warnings here is quite the
right idea; these tests are just for syntax and parsing success.
These functions are called at init-time, and their inputs are hard-coded
so there are no environmental or user factors that could make it fail
or succeed; the error return values are often ignored, and when they're
not, they are usually a fatal error anyway. To ensure that a programmer
mistake is not missed, we now panic instead.
Last breaking change 🤞
* admin: Refactor /load endpoint out of caddy package
This eliminates the caddy package's dependency on the caddyconfig
package, which helps prevent import cycles.
* v2: adapter: register config adapters as Caddy modules
* v2: adapter: simplify adapter registration as adapters and modules
* v2: adapter: let RegisterAdapter be in charge of registering adapters as modules
* v2: adapter: remove underscrores placeholders
* v2: adapter: explicitly ignore the error of writing response of writing warnings back to client
* Implicitly wrap config adapters as modules
Co-authored-by: Matthew Holt <mholt@users.noreply.github.com>
This integrates a feature that was previously reserved for enterprise
users, according to https://github.com/caddyserver/caddy/issues/2786.
The /config and /id endpoints make granular config changes possible as
well as the exporting of the current configuration.
The /load endpoint has been modified to wrap the /config handler so that
the currently-running config can always be available for export. The
difference is that /load allows configs of varying formats and converts
them using config adapters. The adapted config is then processed with
/config as JSON. The /config and /id endpoints accept only JSON.
Along with several other changes, such as renaming caddyhttp.ServerRoute
to caddyhttp.Route, exporting some types that were not exported before,
and tweaking the caddytls TLS values to be more consistent.
Notably, we also now disable automatic cert management for names which
already have a cert (manually) loaded into the cache. These names no
longer need to be specified in the "skip_certificates" field of the
automatic HTTPS config, because they will be skipped automatically.
Matt Holt