parking_solution/wiki/decisions/appliance-provisioning.md

---
type: reference
tags: [parking, deployment, appliance, hardening, runbook, offline-first]
sources: []
updated: 2026-06-23
status: settled
---

# Appliance provisioning runbook (booth PC)

Step-by-step to take a booth PC from factory Windows to a hardened, encrypted, container-running
parking appliance. Written from the **first real provisioning, 2026-06-23**, on the actual hardware
below — every command here was run and verified on that machine, including the firmware-specific
workaround. Companion to [[disk-os-hardening]] (the *why*), [[tpm]] (TPM analysis), and
[[container-deployment]] (the images this runs).

> ⚠ This box is the [[threat-model|outsider-with-the-box]] defence. The load-bearing anti-fraud
> control is still [[reconciliation]] over the [[append-only-event-chain|signed chain]] — disk
> encryption + Secure Boot raise the cost of offline tamper, they don't replace reconciliation.

## Reference hardware (first unit, 2026-06-23)

- **Dell OptiPlex 7070**, **Intel Core i5-8500** (Coffee Lake), 238 GB SATA SSD (`/dev/sda`).
- **TPM 2.0 — discrete Nuvoton** (`Get-Tpm` → `ManufacturerIdTxt NTC`, fw 7.2.1.0). NOT Intel
  PTT/fTPM. Discrete ⇒ an external LPC/SPI bus exists (bus-sniff is a theoretical physical attack on
  PCR-only sealing — accepted; see [[tpm]]). Used PC — previous owner irrelevant.
- Shipped Windows 11; formatted to **Ubuntu 26.04 LTS** (the decided platform — [[desktop-shell-tauri]]).

## 1. BIOS (F2 at the Dell logo)

- **TPM**: leave **On**. Used PC → **Clear the TPM once** (Security → TPM → Clear) so the prior
  owner's keys are wiped before LUKS enrollment. (PPI "Bypass for Clear" was unchecked → it asks for
  physical confirmation at next boot; that's normal.)
- **Secure Boot**: **Enabled**, **Deployed Mode** (not Audit). **"Enable Custom Mode" UNCHECKED** =
  Standard Mode with stock Microsoft keys — this is what Ubuntu's signed shim needs. Do NOT touch
  PK/KEK/db/dbx. NB: the 7070's Expert Key Management is **edit-only** (Save/Replace/Append/Delete —
  no read-only "View Key"), so you **cannot inspect db from BIOS**; verify via the live USB instead
  (step 2).
- **Boot**: UEFI only (no CSM/Legacy — a Legacy install has no Secure Boot / TPM-seal path).
- Set a **BIOS admin password**.

## 2. Boot the Ubuntu 26.04 USB (Secure Boot ON)

- **Flash the ISO DIRECTLY** (Rufus GPT/UEFI, Etcher, or `dd`). **NOT Ventoy** — Ventoy's own
  bootloader isn't in `db`, so Secure Boot rejects it with **`Verification failed: (0x1A) Security
  Violation`** (this is Secure Boot working correctly, not a fault). A directly-flashed Ubuntu USB
  boots the Microsoft-signed shim, which stock `db` trusts.
- **F12** at the Dell logo → pick the USB under **UEFI BOOT**.
- Reaching the installer with Secure Boot ON = positive proof the MS third-party UEFI CA is in `db`
  (the verification the BIOS couldn't show us).

## 3. Encrypted install — the firmware workaround (IMPORTANT)

The 26.04 installer disk page offers: No Encryption / **Encrypt with a passphrase** / **Use
hardware-backed encryption** (+ advanced LVM/ZFS, both ZFS experimental).

- **"Use hardware-backed encryption" FAILS on this 7070** with:
  `PCR_UNUSABLE … error with secure boot policy (PCR7) measurements: generating secure boot profiles
  for systems with timestamp revocation (dbt) support is currently not supported.`
  → Ubuntu's *automated* FDE profiler can't model PCR7 on Dell firmware carrying a `dbt` (UEFI
  timestamp revocation list). It is NOT a TPM or Secure-Boot fault — both are fine.
- **So: choose "Encrypt with a passphrase".** Set a strong passphrase and **SAVE IT OFF-MACHINE**
  (phone / password manager). It is both the boot unlock (until TPM sealing) AND the permanent
  recovery slot. Finish the install.
- Result (verify with `lsblk`): `sda1` vfat `/boot/efi`, `sda2` ext4 `/boot`, `sda3` `crypto_LUKS`
  → `dm_crypt-0` (LVM2) → `ubuntu--vg-ubuntu--lv` ext4 `/`.

## 4. Seal LUKS to the TPM (manual — PCR 7 only)

Do this AFTER first boot. Manual enrollment sidesteps the installer's dbt profiler and lets us pick
PCRs. **Bind to PCR 7 only** (Secure Boot state): it catches the attack that matters (disabling
Secure Boot to boot a tampered kernel) WITHOUT breaking on routine kernel/GRUB updates (which churn
PCRs 4/8/9 → would otherwise drop every boot to the passphrase). Firmware-only PCR 0 is the fallback
if PCR 7 ever errors.

```bash
sudo apt update && sudo apt install -y tpm2-tools
sudo tpm2_pcrread sha256                 # sanity: PCRs 0-10 populated, PCR 7 has a real value

# Enroll the TPM (prompts for the EXISTING install passphrase to authorize the new slot):
sudo systemd-cryptenroll --tpm2-device=auto --tpm2-pcrs=7 /dev/sda3

# Verify TWO slots — keep BOTH (slot 0 password = recovery, slot 1 tpm2 = auto-unlock):
sudo systemd-cryptenroll /dev/sda3
#   SLOT TYPE
#      0 password
#      1 tpm2
```

Wire it into boot (back up first; the mapping is `dm_crypt-0`, the LUKS UUID is in `/etc/crypttab`):

```bash
sudo cp /etc/crypttab /etc/crypttab.bak
sudo sed -i 's/none luks$/none luks,tpm2-device=auto/' /etc/crypttab
cat /etc/crypttab     # → dm_crypt-0 UUID=… none luks,tpm2-device=auto
sudo update-initramfs -u
sudo reboot
```

- **Boots straight to login, no passphrase prompt** = ✅ TPM auto-unlock works (unattended reboot
  achieved — VERIFIED on this unit 2026-06-23).
- Still prompts = PCR mismatch; type the passphrase (NOT locked out), then retry with
  `--tpm2-pcrs=0`. The `password` slot + `crypttab.bak` make this fully reversible.

> **Re-seal runbook:** a BIOS update / Secure Boot change alters PCR 7 → the TPM refuses → boot
> falls back to the passphrase prompt (not a brick). After such a change, re-run step 4's
> `systemd-cryptenroll --wipe-slot=tpm2 --tpm2-device=auto --tpm2-pcrs=7 /dev/sda3` to re-bind.

## 5. GRUB password — EDIT-ONLY (VERIFIED 2026-06-23)

Closes the `init=/bin/bash` / `systemd.unit=rescue.target` local-root hole: without it, anyone at
the keyboard presses `e` at the GRUB menu, edits the kernel cmdline, and boots to a **root shell with
no login**. **The PCR-7 TPM seal does NOT cover this** — editing the GRUB cmdline doesn't change
PCR 7 (Secure Boot policy), so the TPM still releases the key and the attacker lands on the decrypted
disk. This is the specific countermeasure for the [[threat-model|operator-at-the-booth]]. Use
**edit-only** mode (`--unrestricted`) so the box still boots UNATTENDED — the password is required
only to EDIT entries, never to boot.

```bash
grub-mkpasswd-pbkdf2          # enter a password (twice) → copy the grub.pbkdf2.sha512.* hash
```

Add the superuser (paste YOUR hash) to the end of `/etc/grub.d/40_custom`:
```
set superusers="admin"
password_pbkdf2 admin grub.pbkdf2.sha512.10000.<YOUR_HASH>
```

Make menu entries bootable WITHOUT the password (edit-only) — in `/etc/grub.d/10_linux`, set the
active `CLASS=` line to include `--unrestricted`:
```
CLASS="--class gnu-linux --class gnu --class os --unrestricted"
```

Regenerate + VERIFY BOTH HALVES landed in the real config BEFORE rebooting (a GRUB misconfig means a
rescue-USB recovery):
```bash
sudo update-grub
sudo grep -c "password_pbkdf2" /boot/grub/grub.cfg   # want ≥1 (password present)
sudo grep -c "unrestricted"    /boot/grub/grub.cfg   # want ≥1 (entries bootable w/o password)
sudo reboot
```

✅ VERIFIED on this unit: boots straight to login (no GRUB prompt, TPM still auto-unlocks) AND
pressing `e` at the menu prompts for `admin` + password. Store the GRUB password off-machine
(alongside the LUKS passphrase).

> OS hardening on the first unit is now COMPLETE: LUKS FDE + TPM auto-unlock (PCR 7) + Secure Boot
> (Deployed) + GRUB edit-lock.

## 5b. Further hardening (TODO — not yet done)

- **Key-based SSH only** (disable password auth) if SSH is enabled at all.
- **No/locked-down desktop** — single-purpose; autostart the kiosk ([[desktop-shell-tauri]]).
- Consider moving the host **event-signing key into the TPM** (non-extractable) — [[tpm]], [[open-questions]] #12.
- `sudo apt autoremove` the leftover old kernel (`linux-*-7.0.0-14`) once the new one is proven.

## 6. Runtime — Docker stack

Per [[container-deployment]]: install Docker Engine + compose, then run the `parking-server` +
`parking-vision` images via `docker-compose.yml -f docker-compose.prod.yml`. Provide a real
`JWT_SECRET` (`openssl rand -hex 32`) and `COOKIE_SECURE=0` (plain-http booth LAN — see
[[disk-os-hardening]] deploy-time runbook). Images are published to the Gitea registry by
`build-images.yml` on push to dev/main.

## Quick-reference: the gotchas, in order they bit us

1. Ventoy USB → `0x1A` Security Violation under Secure Boot → flash the ISO directly instead.
2. 7070 BIOS has no "View Key" → can't inspect db; the live-USB boot IS the verification.
3. Installer "hardware-backed encryption" → `PCR_UNUSABLE`/dbt → use passphrase LUKS + manual seal.
4. Bind TPM to **PCR 7 only**, not a multi-PCR set (kernel updates churn 4/8/9 → passphrase every boot).
5. Always keep the **password slot** + an off-machine copy of the passphrase (TPM is never the only key).
6. GRUB password MUST be **edit-only** (`--unrestricted` on entries) or it prompts on EVERY boot →
   breaks unattended reboot. Verify `grep -c unrestricted /boot/grub/grub.cfg` ≥1 before rebooting.