Your keys, not mine

While rewriting the READMEs after taking the Rasputin repos public, I wrote “release images bake no SSH key,” went to verify it, and found the opposite: CI was injecting my public key into root’s authorized_keys on every published image — node OS and firewall both — via a repo variable (RASPUTIN_SSH_AUTHORIZED_KEY) read at build time.

Why it existed: until July 2nd these repos were private and the images only ever ran on my own bench clusters, where a baked support key is just provisioning. Public repos change the threat model, not just the audience. “The vendor has root on your firewall” is a correct description of what I was shipping, and it’s disqualifying regardless of intent.

Timeline:

• Jul 8, evening — found while fact-checking README claims. Same night: updated all READMEs to disclose the baked key and how to remove it.
• Jul 8, later — landed the replacement: seed-supplied keys (below). Deleted the build-time injection path entirely.
• Jul 9 — published the first images without it (os dev.92, firewall dev.57), plus the first stable release.

The fix — seed-supplied keys:

• The FAT seed partition every node reads on first boot takes an optional line: RASPUTIN_SSH_AUTHORIZED_KEY="ssh-ed25519 AAAA... you@laptop".
• Node OS: the rootfs is read-only squashfs, so /root/.ssh/ can’t hold it. First boot writes the key to the persistent data partition (/var/lib/rasputin/dropbear/), where the SSH host keys already live so host identity survives A/B updates. dropbear points there.
• Firewall: the overlay is writable and dropbear reads /etc/dropbear/authorized_keys natively. Two lines.
• Blank seed line = no network SSH at all. Password auth over SSH is disabled unconditionally, so the node is web UI + local console only.
• The build-time path is deleted, not disabled — the pipeline cannot bake a key into a public image anymore, mine included. My bench clusters provision through the same seed field.

Also shipped: first stable release. 2026.07.1, one CalVer tag across control plane, node OS, and firewall image. Stable and dev channels both carry the no-baked-key images.

Build failure of the week: the firewall fix’s first build died on a SHA mismatch — snort.org republishes its community ruleset roughly weekly and we pin the tarball by hash. Seventh re-pin since June. The scheduled canary catches it; the mirror that would end it is still on the backlog.

Takeaway: every default set when the only user was me needed re-auditing the day the repos went public. This was the worst one. If you find another, file it.

Rasputin is an open-source (AGPL) homelab cluster system — a control plane, node OS, and firewall image that make a few Raspberry Pis or N100 boxes behave like one appliance. It’s pre-alpha, on GitHub, and I’m looking for a handful of design partners to run it and tell me what’s broken.