relay-adoption-source-bg.ts

1import {2  createPairingInvitation,3  pairingInvitationUrl,4  parsePairingInvitation,5} from "../shared/pairing-invitation";6import {7  openRelayPairingSocket,8  type PairingSocket,9} from "../shared/pairing-dial";10import {11  noiseNKResponder,12  type NoiseNKSession,13} from "../shared/noise-js";14import {15  grantAdoption,16  isAdoptRequest,17  receiveFrame,18  type AdoptRequest,19} from "../shared/vault-adopt";20import {21  derivePairingSAS,22  type PairingTransport,23} from "../shared/pairing-handshake";24import {25  bytesToHex,26  deriveRendezvousSecret,27  generatePairingRendezvousToken,28} from "../shared/rendezvous";29import { getLocalPairingIdentity } from "./device-identity";30import { getSyncSettings, relayInForce } from "./sync-settings";31import { getLicenseKey, isProUser } from "./license";32import { getRootKeyHex, isUnlocked, verifyMainPassword } from "./vault";33import { computeVaultId } from "../shared/sync-identity";34import { upsertPairedDevice } from "./paired-devices";35import { triggerSyncIfReachable } from "./sync-trigger";3637const SOURCE_WINDOW_MS = 5 * 60 * 1000;3839function push(type: string, payload: unknown): void {40  try {41    const maybe = chrome.runtime.sendMessage({ type, payload }) as unknown;42    if (maybe && typeof (maybe as Promise<unknown>).catch === "function") {43      (maybe as Promise<unknown>).catch(() => undefined);44    }45  } catch {46    // The popup may have closed. The pending approval fails closed on cleanup.47  }48}4950let inFlight = false;51let activeSocket: PairingSocket | null = null;52let pendingConsent: ((approved: boolean) => void) | null = null;5354export function isRelayAdoptionSourceInFlight(): boolean {55  return inFlight;56}5758/**59 * Occupy the non-buffering room before returning the invitation to the UI.60 * All long-term key material remains in the background service worker.61 */62export async function startRelayAdoptionSource(): Promise<{63  invitation: string;64}> {65  if (inFlight) throw new Error("adoption_source_in_progress");66  if (!isUnlocked()) throw new Error("vault_locked");67  inFlight = true;6869  let local: Awaited<ReturnType<typeof getLocalPairingIdentity>> | null = null;70  try {71    const settings = await getSyncSettings();72    const relayUrl = relayInForce(settings);73    local = await getLocalPairingIdentity();74    const token = generatePairingRendezvousToken();75    const encoded = createPairingInvitation(relayUrl, token);76    const invitation = parsePairingInvitation(encoded);77    if (!invitation) throw new Error("invitation_generation_failed");7879    const socket = await openRelayPairingSocket(pairingInvitationUrl(invitation));80    activeSocket = socket;81    const readyLocal = local;82    void runSourceSession(83      socket,84      token,85      relayUrl,86      readyLocal,87    ).finally(() => {88      readyLocal.privateKey.fill(0);89      readyLocal.publicKey.fill(0);90      clearState();91    });92    return { invitation: encoded };93  } catch (error) {94    local?.privateKey.fill(0);95    local?.publicKey.fill(0);96    clearState();97    throw error;98  }99}100101/**102 * Wrong passwords do not consume the pending decision; cancel does.103 */104export async function confirmRelayAdoptionSource(105  password: string | null,106): Promise<{ valid: boolean }> {107  const pending = pendingConsent;108  if (!pending) return { valid: false };109  if (password === null) {110    pendingConsent = null;111    pending(false);112    return { valid: true };113  }114  const valid = await verifyMainPassword(password);115  if (valid) {116    pendingConsent = null;117    pending(true);118  }119  return { valid };120}121122export function cancelRelayAdoptionSource(): void {123  pendingConsent?.(false);124  pendingConsent = null;125  activeSocket?.close();126  clearState();127}128129async function runSourceSession(130  socket: PairingSocket,131  expectedToken: string,132  relayUrl: string,133  local: Awaited<ReturnType<typeof getLocalPairingIdentity>>,134): Promise<void> {135  const timeout = setTimeout(() => socket.close(), SOURCE_WINDOW_MS);136  let noise: NoiseNKSession | undefined;137  try {138    const hello = decodeJson<{ type?: unknown; token?: unknown }>(139      await socket.receive(),140    );141    if (hello.type !== "PEACH_HELLO" || typeof hello.token !== "string" ||142        !constantTimeEqual(hello.token, expectedToken)) {143      throw new Error("invalid_invitation");144    }145    socket.send(encodeJson({146      type: "PEACH_HELLO_ACK",147      ephemeralPublicKeyHex: bytesToHex(local.publicKey),148    }));149150    const session = await noiseNKResponder(151      local.privateKey,152      local.publicKey,153      async (bytes) => socket.send(bytes),154      () => socket.receive(),155    );156    noise = session;157    const channel: PairingTransport = {158      async send(plaintext) { socket.send(session.encrypt(plaintext)); },159      async receive() { return session.decrypt(await socket.receive()); },160    };161    const request = await receiveFrame(channel);162    if (!isAdoptRequest(request)) throw new Error("expected_ADOPT_REQUEST");163164    const device = await grantAdoption(channel, request, {165      sourceIdentity: local.identity,166      pairState: {167        rendezvousSecretHex: bytesToHex(168          deriveRendezvousSecret(session.handshakeHash),169        ),170        relayUrl,171      },172      async rootKeyHex() {173        // grantAdoption calls this only after local password approval and the174        // receiver's encrypted ADOPT_CONFIRM(true).175        const value = getRootKeyHex();176        if (!value) throw new Error("vault_locked");177        return value;178      },179      async vaultId() {180        const value = getRootKeyHex();181        if (!value) throw new Error("vault_locked");182        const bytes = hexToBytes(value);183        try {184          return await computeVaultId(bytes);185        } finally {186          bytes.fill(0);187        }188      },189      async license() {190        return (await isProUser()) ? (await getLicenseKey()) ?? undefined : undefined;191      },192      onConsent: (adoptRequest) => requestConsent(193        adoptRequest,194        derivePairingSAS(session.handshakeHash),195      ),196      upsertPairedDevice,197    });198    if (!device) {199      push("ADOPTION_SOURCE_RESULT", {200        status: "error",201        error: "adoption_rejected",202      });203      return;204    }205    push("ADOPTION_SOURCE_RESULT", { status: "complete", device });206    // The Android receiver starts its relay listener as soon as its source207    // record is durable. Try once now and once after service startup settles so208    // the newly adopted empty vault receives its first sync without another209    // user action. Both calls are best-effort and contain no user data.210    void triggerSyncIfReachable({ reason: "manual", force: true });211    setTimeout(() => {212      void triggerSyncIfReachable({ reason: "manual", force: true });213    }, 1_000);214  } catch {215    push("ADOPTION_SOURCE_RESULT", {216      status: "error",217      error: "adoption_failed",218    });219  } finally {220    clearTimeout(timeout);221    noise?.close();222    socket.close();223  }224}225226function requestConsent(request: AdoptRequest, sas: string): Promise<boolean> {227  push("ADOPTION_SOURCE_SAS", {228    sas,229    receiverDeviceName: request.device_name,230  });231  return new Promise<boolean>((resolve) => {232    pendingConsent = resolve;233  });234}235236function clearState(): void {237  pendingConsent?.(false);238  pendingConsent = null;239  activeSocket = null;240  inFlight = false;241}242243function constantTimeEqual(a: string, b: string): boolean {244  if (a.length !== b.length) return false;245  let diff = 0;246  for (let i = 0; i < a.length; i++) diff |= a.charCodeAt(i) ^ b.charCodeAt(i);247  return diff === 0;248}249250function encodeJson(value: unknown): Uint8Array {251  return new TextEncoder().encode(JSON.stringify(value));252}253254function decodeJson<T>(value: Uint8Array): T {255  return JSON.parse(new TextDecoder().decode(value)) as T;256}257258function hexToBytes(hex: string): Uint8Array {259  const out = new Uint8Array(hex.length / 2);260  for (let i = 0; i < out.length; i++) {261    out[i] = Number.parseInt(hex.slice(i * 2, i * 2 + 2), 16);262  }263  return out;264}