Every diagnostic command nebula has was reachable through exactly one door:
the built-in ssh debug server. That server is off by default, and turning it
on means generating a host key, writing an sshd block with authorized public
keys, and SIGHUPing the daemon. That is a lot of ceremony to answer "what
version is this node running".
Nebula now serves the same commands over a local unix socket, enabled by
default, and `nebula ctl <command>` runs them. The socket lives in a 0700
directory so filesystem permissions are the access control; no keys, nothing
on the network. Failing to create it is logged and never blocks startup.
The command registry was already transport neutral, so this is mostly new
transport rather than new commands:
- diag/ holds the registry, dispatch, writer and wire protocol, moved out
of sshd because none of it was ever about ssh. sshd and ctl.go dispatch
against one shared registry.
- commands.go holds every command implementation, moved out of ssh.go
(which was 85% not ssh) and renamed off the ssh prefix. Adding a command
there makes it available over both transports.
- ssh.go keeps only host keys, authorized users, and the listen address.
- ctl.go supervises the socket, following the statsServer lifecycle shape.
The wire protocol frames the response rather than terminating it, because
print-cert -raw and list-hostmap -json both emit arbitrary bytes that no
sentinel could safely delimit. argv travels as a list so quoting survives.
Exit statuses are real: 0, 2 for usage, 127 for an unknown command.
Two things fall out. The ssh console now reports a real exit status instead
of a hardcoded zero, so `ssh host list-hostmap` is scriptable too. And eight
command callbacks that silently returned nil on a flags type mismatch now
report it, which the exit status makes visible.
Windows is a stub returning a clear "not supported" until it gets a named
pipe with a security descriptor; iOS and Android are never enabled, having no
daemon for a CLI to attach to.
Breaking for embedders of the sshd package: NewSSHServer takes a
*diag.Registry, SSHServer.RegisterCommand is gone in favor of registering on
that registry, and the command types live in diag rather than sshd.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014fya5fTXGiwX72FUmoL9y3
* firewall can distinguish if the host connecting has an overlapping network, is a VPN peer without an overlapping network, or is a unsafe network
* Cross stack subnet stuff (#1512)
* experiment with not filtering out non-common addresses in hostinfo.networks
* allow handshakes without overlaps
* unsafe network test
* change HostInfo.buildNetworks argument to reference the cert
* try to make certificate addition/removal reloadable in some cases
* very spicy change to respond to handshakes with cert versions we cannot match with a cert that we can indeed match
* even spicier change to rehandshake if we detect our cert is lower-version than our peer, and we have a newer-version cert available
* make tryRehandshake easier to understand
* upgrade to yaml.v3
The main nice fix here is that maps unmarshal into `map[string]any`
instead of `map[any]any`, so it cleans things up a bit.
* add config.AsBool
Since yaml.v3 doesn't automatically convert yes to bool now, for
backwards compat
* use type aliases for m
* more cleanup
* more cleanup
* more cleanup
* go mod cleanup
* Support NIST curve P256
This change adds support for NIST curve P256. When you use `nebula-cert ca`
or `nebula-cert keygen`, you can specify `-curve P256` to enable it. The
curve to use is based on the curve defined in your CA certificate.
Internally, we use ECDSA P256 to sign certificates, and ECDH P256 to do
Noise handshakes. P256 is not supported natively in Noise Protocol, so
we define `DHP256` in the `noiseutil` package to implement support for
it.
You cannot have a mixed network of Curve25519 and P256 certificates,
since the Noise protocol will only attempt to parse using the Curve
defined in the host's certificate.
* verify the curves match in VerifyPrivateKey
This would have failed anyways once we tried to actually use the bytes
in the private key, but its better to detect the issue up front with
a better error message.
* add cert.Curve argument to Sign method
* fix mismerge
* use crypto/ecdh
This is the preferred method for doing ECDH functions now, and also has
a boringcrypto specific codepath.
* remove other ecdh uses of crypto/elliptic
use crypto/ecdh instead
