Lutz Finsterle
64b20a54dc
Local snapshots lived only on the Pi running OpenBAO, so a dead SD card took
both the service and its backups. This was the top remaining hardening item.
Scope note: fids2 is 192.168.0.234, same LAN as the Pi. This is genuinely
OFF-HOST but not off-site -- it covers SD-card death, hardware failure and bad
upgrades, not fire, theft, or LAN-wide ransomware.
Encrypted with GPG to HOME_SECURE (07E23DC55C0FCF76) before anything touches
the share. Two reasons:
- The CIFS mount is uid=1000,file_mode=0664, so the root-only 0600 on
/var/backups/openbao is LOST on arrival. Ciphertext makes the share's
permissions irrelevant, which is what makes it safe to include the unseal
material and ship a genuinely restorable DR set.
- NOT the transit engine, deliberately: you would need a working OpenBAO to
decrypt the backup you are restoring because OpenBAO is broken. Only the
public key is on the Pi (committed here; verified no private-key blocks).
The script never talks to OpenBAO, so it still runs while OpenBAO is down.
Bundle = both raft snapshots + init-output.json + unsealer-init.json + a
generated RESTORE.md carrying the restore ORDER (unsealer first, then main)
and the no-downgrade warning, so the recovery instructions travel inside the
backup rather than living only in a repo the Pi might take with it.
Verified by full round-trip from the NAS copy: decrypt, extract, gzip -t and
sha256sum -c both snapshots, and confirmed the recovered unseal keys are
byte-identical to the live ones. Plaintext was shredded afterwards.
Two guards, both tested to actually fire:
- Refuses to ship if the newest local snapshot is older than 48h, rather
than quietly uploading a stale DR copy. This is the exact failure that
went unnoticed for 24 days (tested: 120h-old snapshot -> exit 1).
- Verifies the destination is really on a cifs/smb filesystem. Found during
testing: as root a bare `mkdir -p` SUCCEEDS when the automount is down,
creating a local directory under the mount point, so every "offsite"
backup would silently land on the same Pi. Checking that some path is a
mountpoint was not enough -- it now stats the filesystem type of the
destination's deepest existing ancestor (tested: ext2/ext3 -> exit 1).
OnFailure mails an alert like the other units. Retains 30 bundles (~143KB
each). Daily at 03:40, a clear gap after the 02:30 local snapshot.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NFtVLA7VVqXL5G2S18c4Jk
14 lines
386 B
SYSTEMD
14 lines
386 B
SYSTEMD
[Unit]
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Description=Daily offsite copy of the OpenBAO DR bundle
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[Timer]
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# Local snapshots run at 02:30 (+ up to 15m jitter), so 03:40 leaves a clear
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# gap and always ships that morning's snapshot. The script independently
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# refuses to run if the newest local snapshot is older than 48h.
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OnCalendar=*-*-* 03:40:00
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Persistent=true
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RandomizedDelaySec=15m
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[Install]
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WantedBy=timers.target
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