Archived
jschoubben
ea6569277d
Given the broker's address and its certificate, mesh-control now issues a token carrying everything ADR 0004 asks for: where to connect, what to expect there, whose signature to believe afterwards, and a one-time right to join. Verified by decoding one and checking the fingerprint against `openssl x509 | sha256sum` -- they match. The fingerprint is derived from the certificate on disk and never configured. A configured pin can drift from the certificate it describes, and a drifted pin is worse than none: every node issued a token during the drift refuses to connect, and the failure looks like an attack rather than a mistake. Computed over DER, which is what a client sees on the wire. Hashing the PEM text instead would mean the same certificate, re-wrapped with different line endings, produced a different pin -- there is a test for exactly that, and one for pointing this at tls.key by mistake, which would otherwise produce a confident pin over the wrong file. Having no broker stays a state rather than a failure: a control plane holds records and a signing key without one. Having half a broker is refused, because a token with an address and nothing to check it against invites a node to trust whatever answers. Fault injection caught the same weak test I wrote earlier in the day -- asking whether something failed rather than why, so deleting the guard changed nothing because it failed one line later anyway. Both are now asserted on the reason.