julian
9e442586af
New concept page backup-recovery.md resolving the design half of open-question #5. Driving scenario: a stolen/destroyed PC whose LUKS+TPM disk is unrecoverable by design — recovery stands up a NEW PC, restores a backup, and keeps signing the SAME chain. Settled: admin-driven encrypted full-DB backup (SQLite online-backup/VACUUM INTO, snapshots included) to local/USB, SMB/NFS, or SFTP targets; manual button + an in-process daily timer; keep-last-N + dailies retention; restore is admin-only / out-of-band (operator-adversary surface). A restored copy must still verifyChain. Key custody (the load-bearing decision, bears on #6): three independent keys — EVENT_SIGNING_KEY kept an extractable, escrowed software key DECOUPLED from the TPM so the ledger survives total hardware loss (the conscious trade: a TPM-sealed signing key would be unforgeable but permanently unverifiable after the machine dies); a NEW dedicated park_buzi_backup_key in Komodo for backup encryption, separate from the signing key; the LUKS/TPM disk key, appliance-only and deliberately non-recoverable. Keys are never inside the backup they unlock. Updated open-questions #5 (design SETTLED) + #10 note; disk-os-hardening deploy runbook (why the signing key is not sealed + park_buzi_backup_key); index catalog + concept count. Design only — not yet built. Claude-Session: https://claude.ai/code/session_01Xcm6ikLgGoCxxHrxtjkk5V
65 lines
4.0 KiB
Markdown
65 lines
4.0 KiB
Markdown
---
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type: concept
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tags: [parking, security, platform]
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sources: [parking-system-architecture]
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updated: 2026-06-29
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---
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# Disk / OS Hardening
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Worthwhile, but **not the main event** — it defends against the outsider-with-physical-access,
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not the operator (see [[threat-model]]). (See [[parking-system-architecture]] §3.)
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Physical-access attacks on Windows are trivial (boot media + password-reset tools), so a
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**dedicated Linux machine is the correct platform** — not Windows or WSL. This is a
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[[standing-decisions|standing decision]].
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- **LUKS full-disk encryption** — defeats boot-from-USB.
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- **GRUB password + Secure Boot** — prevents boot-parameter tampering / unsigned loaders.
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- **No desktop environment** — single-purpose appliance.
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- **Key-based SSH only.**
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- **[[tpm|TPM 2.0]]** _(recommended, 2026-06-21)_ — seals the LUKS key to the boot chain so the disk
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**auto-unlocks only on an untampered boot**, making encryption-at-rest compatible with **unattended
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reboot** (a booth must come back up after a power cut without a human typing a passphrase). Also a
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candidate home for the non-extractable host event-signing key. Caveats (live-root limit, bus-sniff,
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PCR brittleness, mandatory recovery passphrase + re-seal runbook) on [[tpm]]; implementation is
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[[open-questions]] #12.
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With LUKS in place, **SQLCipher becomes optional** defence-in-depth rather than the critical
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layer. (The custom controller adds its own: ESP32 flash encryption + secure boot — see
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[[esp32-custom-controller]].)
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> **Step-by-step OS install + TPM-seal procedure** (BIOS → encrypted install → manual PCR-7 TPM
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> seal, with the Dell-7070-specific `dbt` workaround) lives in [[appliance-provisioning]] — written
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> from the first real provisioning (2026-06-23) and verified on hardware. **OS hardening on the first
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> unit is COMPLETE: LUKS FDE + TPM auto-unlock (PCR 7, unattended) + Secure Boot (Deployed) + GRUB
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> edit-lock** (the GRUB password is the specific countermeasure to the `init=/bin/bash` root-shell
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> hole that PCR-7 sealing does NOT cover). Resolves the implementation half of [[open-questions]] #12
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> for unit 1.
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## Deploy-time server configuration (runbook)
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Env in `apps/server/.env` on the appliance (see `apps/server/.env.example`). The security-load-bearing ones:
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- **`JWT_SECRET`** — ≥32 random chars; the server refuses to boot without a strong one (no
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insecure default). `openssl rand -hex 32`. See [[local-jwt-auth]].
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- **`EVENT_SIGNING_KEY`** — dedicated HMAC key for the signed ledger; ≥16 chars. Falls back to
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`JWT_SECRET` with a warning if unset — set a dedicated one before production. Deliberately kept an
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**extractable, escrowed software key (NOT TPM-sealed)** so the ledger survives total hardware loss —
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see [[backup-recovery]] for the custody trade vs. [[open-questions]] #6.
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- **`park_buzi_backup_key`** *(planned)* — dedicated key for encrypting [[backup-recovery|DB backups]],
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**separate** from `EVENT_SIGNING_KEY` (independent rotation; backups travel, the signing key
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shouldn't). Both escrowed offsite in [[fleet-deployment-komodo|Komodo]]; recovery needs both, held
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out-of-band.
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- **`COOKIE_SECURE=0`** — **REQUIRED on the plain-HTTP LAN appliance.** Auth/CSRF cookies are
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`Secure` by **default** (fail-safe). The appliance serves the SPA same-origin over **plain
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http** on the booth LAN, where a `Secure` cookie is **never sent** — so without this opt-out
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**operators cannot log in**. Set it deliberately. (A TLS/reverse-proxied deploy leaves it
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UNSET so cookies stay `Secure`.) This replaced the old `NODE_ENV=production` gate, which
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silently dropped `Secure` if the var was forgotten. See [[local-jwt-auth]].
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> The plain-http booth LAN is acceptable because it's an **isolated, single-purpose network**
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> (the only browser is the booth's own; access controllers sit on a separate VLAN — see
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> [[network-isolation]], [[trust-boundary]]). `Secure`-off is a network-scoped decision, not a
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> blanket weakening; the JWT stays HttpOnly + SameSite=Strict and CSRF double-submit still applies.
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