Commit Graph
3 Commits
Author SHA1 Message Date
hermes 3e20b558a5 fix(ci): harden the CA refresh script and add shellcheck to CI
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Round-2 review findings, all low severity.

- `curl` now has `--connect-timeout` and `--max-time`, so an unreachable API
  server fails the job instead of hanging the runner indefinitely.

- A guard for a kubeconfig with no cluster entries, or an empty one, with a
  clear message rather than an opaque kubectl error.

- The fingerprint mismatch message now prints both the expected and the
  actual value, which cuts the time to diagnose the next CA rotation.

- `set -euo pipefail` was already there; the script now passes shellcheck
  clean, and a shellcheck step was added to the CI test job so the
  operational scripts get the same treatment as the Python code.
2026-11-09 12:15:50 +10:00
hermes a4b3d40e2d fix(ci): pin the cluster CA in the repo rather than in a secret
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The CA fingerprint is not a secret.  It is a public value that anyone can
read straight off the certificate, so pinning it in a Gitea secret was the
wrong shape:

- A change to it would be invisible - no commit, no review.
- Nobody with secret-write access could silently repoint the CI runner at a
  different CA.

It now lives in `scripts/cluster-ca.sha256`, so changing it is a reviewable
commit.  The script reads it from there, and still accepts an override as
its first argument.

This also removes the need for a `KUBE_SERVER_CA_FINGERPRINT` secret, which
the bot token cannot create anyway - the Actions secrets API is owner-only.

The behaviour is unchanged: the CA is fetched over an unverified connection
but only USED if it matches the pinned fingerprint, so an intercepted CA is
refused.  Re-tested against the live API server - the matching fingerprint
refreshes the CA and kubectl then works; a wrong one is refused and the
stale CA is left in place.
2026-11-09 12:13:27 +10:00
hermes ce6f5b7962 fix(ci): pin the cluster CA fingerprint instead of trusting a fetched CA
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The review was right on both counts, and both are fixed.

1. MITM. Fetching the CA over an unverified connection (`curl -sk`) and then
   trusting it is a privilege-escalation hole: the runner holds cluster-admin
   credentials, so an attacker able to intercept the fetch could hand us a CA
   of their choosing and then read everything sent over the connection.

   The CA is now PINNED. It is still fetched over an insecure connection, but
   it is only USED if its SHA-256 fingerprint matches
   `KUBE_SERVER_CA_FINGERPRINT`. An intercepted CA will not hash to the
   pinned value, so it is refused. If the secret is not set, the job fails
   rather than trusting an unverified CA.

2. The hardcoded cluster name. `kubectl config set-cluster default` creates a
   NEW cluster entry when the kubeconfig's entry is called something else,
   leaving the original (and its stale CA) in use. The name is now read from
   the kubeconfig: `{.clusters[0].name}`.

The bash is also moved out of the YAML into `scripts/kube-ca-refresh.sh`, so
it can be read, reviewed and tested on its own rather than as a wall of
shell inside a workflow file.

All three paths are tested against the live API server:

- no fingerprint supplied   -> refuses, exit 1
- wrong fingerprint        -> refuses, exit 1
- correct fingerprint      -> refreshes the CA, exit 0, kubectl then works
2026-11-09 12:11:56 +10:00