New module kiosk/src/at_rest.rs. Derives an AES-256-GCM key via HKDF
from a Pi-bound value:
1. /proc/device-tree/serial-number (Pi 5 firmware exposes it)
2. /proc/cpuinfo Serial line (older kernels)
3. /etc/machine-id (non-Pi dev fallback)
File format: "BFE1" magic || 12-byte random nonce || ciphertext+tag.
Atomic write via tempfile + rename so a crash mid-write can't leave a
half-encrypted file.
Wired into kiosk/src/server.rs at every file I/O touching sensitive
state:
- kiosk.key (bearer token to BF server)
- local.key (LAN-side API auth key)
- bundle.json (cached bundle with RTSP credentials in URL form)
Migration: read paths tolerate legacy plaintext (kiosks upgraded from a
pre-at_rest build) AND re-store as ciphertext on the first read. One-
shot upgrade — subsequent boots skip the migration write.
Threat model defended: SD card extraction. Attacker who pulls the card
can't decrypt without also having the same physical Pi (CPU serial is
hardware-bound). Doesn't defeat an attacker who has both — at that
point they ARE the kiosk. Bar is raised from "trivially extract every
camera password" to "must steal the device intact."
Not defended: TPM-style attestation, remote attestation, sealed boot.
Pi 5 has no TPM and we don't ship a secure-boot config.
Tests in-module: round-trip short bytes, round-trip JSON, legacy
plaintext passthrough.
Phase 3 of the OS OTA pipeline. New module kiosk/src/os_update.rs polls
/api/kiosk/os/check with the kiosk's compatibility string and current OS
version (read from /etc/betterframe/os-compatibility +
/etc/betterframe/os-version, both written by the image build), downloads
the bundle, sha256-verifies the transport, and hands off to
`rauc install`. RAUC takes it from there: CMS signature verify against
/etc/rauc/keyring.pem, copy into inactive A/B slot, arm tryboot via the
custom bootloader backend, return. We then post /api/kiosk/os/applied
and `systemctl reboot` into the new slot.
Wired into the existing 60s heartbeat loop in ui.rs, gated by
BF_ENABLE_OS_OTA=1 (default OFF so dev kiosks on non-A/B images don't
keep trying + failing). Runs BEFORE the kiosk-binary check on each tick
so an OS bundle that ships an updated kiosk binary doesn't race the
firmware path.
On clean-boot heartbeat success we now also call `rauc status
mark-good` so the boot-attempts counter resets — three bad boots in a
row will auto-roll back without us needing a separate rollback path.
What's NOT in this commit:
- A/B partition layout in the pi-gen image (task #6, blocks actual
deployment — bundles can be served + accepted but `rauc install`
will refuse without two valid slots).
- Admin UI for managing releases + rollouts (task #4).
- WorkerMsg made pub + re-exported at crate root so local_server can send
through the UI channel.
- ed25519_dalek::pkcs8::DecodePublicKey trait import — needed for
VerifyingKey::from_public_key_pem call site.
- Workflow: pushes to master now auto-trigger a dev-channel build (in
addition to tag-pushes for stable/beta). Concurrency group cancels
superseded master builds; tag builds never cancel each other.
Kiosk now exposes :18090 with two surfaces:
- GET /local/layout/:id?key=<kiosk_local_key>
Bookmark-friendly layout switch on this kiosk. Auth = kiosk-generated
local key (32 random bytes, hex, stored at <state_dir>/local.key).
- ANY /proxy/* — forwards to BF server with the request's Authorization
header preserved. Lets LAN clients reach a cloud-hosted BF server via
the kiosk's local socket; kiosk adds no auth of its own.
Heartbeat reports {local_key, local_port}; kiosks table grows
local_key/local_port/local_last_ip columns. Admin kiosk edit page now
shows the local URLs as a copy-paste block.
Override port: BF_KIOSK_LOCAL_PORT. Disable: BF_KIOSK_LOCAL_DISABLE=1.
Multi-display:
- Bundle ships displays[] each with own layouts + idle/sleep
- Rust kiosk creates one ApplicationWindow per gdk monitor
- Per-display state (layout, idle, sleep) via HashMap
- WARM_CAMERAS pool shared across displays
- Backward-compat top-level display/layouts still emitted
System Health (/admin/health):
- Online status, CPU temp (color-coded), fan RPM/PWM
- Bundle version mismatch detection
- 30s auto-refresh
Camera snapshot/test:
- shared/snapshot.ts: ffmpeg/gst-launch fallback, 5s timeout
- /admin/entities/:id/snapshot returns JPEG
- EntityEditPage shows live preview with Refresh
GPIO (Pi buttons/sensors):
- kiosk_gpio_bindings table + CRUD admin UI
- Bundle ships gpio_bindings[]
- kiosk/src/gpio.rs with gpiod crate, worker thread per pin
- Edge events POST to /api/kiosk/event with source_type=gpio
Layout switch fixes:
- GET aliases added so direct URL hits work
- New /admin/displays/:displayId/layout/:layoutId for multi-display
- DisplayEditPage gets "Switch Layout Now" section
Node-RED embed:
- /admin/nodered renders iframe at /nrdp/
- Sandbox attrs allow scripts/forms/popups
- Sidebar link now opens embedded view
Server side:
- service-coordinator-ws: full WS implementation using ws package
- Auth via ?token=<kiosk_key> query param
- Coordinator registry for cross-plugin notification
- Admin mutations call notifyKiosks() → server pushes reload-bundle
- 30s ping/pong heartbeat
Kiosk side:
- Rust ws_client with tokio runtime + tokio-tungstenite
- Auto-reconnect with exponential backoff (1s → 60s cap)
- On reload-bundle: re-fetches bundle, re-renders layout
- Pong replies to server pings
Also fix: auto-suffix kiosk name on UNIQUE collision (re-pair with
same hostname no longer fails).
