code-pairing.test.ts

1// Code pairing — the PAIR_IDENTITY half over an address-bearing pairing code.2//3// Driven entirely through the dependency-injection seam (CodePairingDeps and a4// fake PairingSocket), so no real WebSocket or Noise crypto runs — except the5// SAS KAT, which calls the REAL `derivePairingSAS` to pin cross-implementation6// agreement with the peer.78import { beforeEach, describe, expect, it, vi } from "vitest";910import {11  pairWithCode,12  type CodePairingDeps,13  type CodePairingCallbacks,14} from "./code-pairing";15import type { PairingSocket } from "../shared/pairing-dial";1617// REAL SAS implementation — reused, not re-derived (ground truth §5).18import { derivePairingSAS } from "../shared/pairing-handshake";19import { encodePairingCode } from "../shared/pairing-code";20import type { LocalIdentity } from "../shared/pairing-handshake";21import type { PairedDevice } from "../shared/sync-types";2223// ── helpers ────────────────────────────────────────────────────────────────2425const enc = (o: unknown) => new TextEncoder().encode(JSON.stringify(o));26const dec = (b: Uint8Array) => JSON.parse(new TextDecoder().decode(b));2728const PEER_EPHEMERAL_HEX = "a".repeat(64);29// The ACK key is the Noise NK responder static, so the encrypted identity must30// repeat exactly this key after the handshake.31const PHONE_LONGTERM_HEX = PEER_EPHEMERAL_HEX;32const PHONE_TOKEN = Uint8Array.of(0xde, 0xad, 0xbe, 0xef);33const PHONE_CODE = encodePairingCode("192.168.4.77", 51555, PHONE_TOKEN);3435const OUR_IDENTITY: LocalIdentity = {36  deviceId: "ext-local-001",37  deviceName: "Firefox on MacBook",38  deviceType: "extension",39  longTermPublicKeyHex: "c".repeat(64),40  signingPublicKeyHex: "d".repeat(64),41  vaultId: "e".repeat(64),42};43const OUR_PRIVATE_KEY = new Uint8Array(32).fill(0x0c);44const OUR_PUBLIC_KEY = new Uint8Array(32).fill(0xcc);4546/**47 * Scripted fake socket. Captures everything sent, and replays a queued list48 * of inbound frames. A frame of `null` means "the socket closes here with no49 * data" — the wrong-code behaviour (no error frame).50 */51function makeFakeSocket(inbound: Array<Uint8Array | null>) {52  const sent: Uint8Array[] = [];53  let closed = false;54  let lastWasClose = false;55  const queue = [...inbound];56  const sock: PairingSocket = {57    send(bytes) { sent.push(bytes); },58    async receive() {59      const next = queue.shift();60      if (next === undefined || next === null) {61        closed = true;62        lastWasClose = true;63        throw new Error("socket closed");64      }65      lastWasClose = false;66      return next;67    },68    close() { closed = true; },69    closedBeforeFrame() { return lastWasClose; },70  };71  return { sock, sent, isClosed: () => closed };72}7374/**75 * A fake Noise session that no-ops encrypt/decrypt (identity transform) so we76 * can drive the PAIR_IDENTITY exchange without real crypto. We stub77 * `noiseNKInitiator` via vi.mock below; this is the shape it returns.78 */79const FAKE_HANDSHAKE_HASH = Uint8Array.from([80  0x0f, 0xba, 0xb8, 0xcd, ...new Array(28).fill(0),81]);8283// Mock the NK initiator: skip the two handshake messages, hand back a session84// whose encrypt/decrypt are identity transforms and whose handshakeHash is the85// cross-platform KAT prefix (so the SAS test below is end-to-end through the flow).86vi.mock("../shared/noise-js", async (orig) => {87  const actual = await orig<typeof import("../shared/noise-js")>();88  return {89    ...actual,90    noiseNKInitiator: vi.fn(async (_responderStatic, _send, _receive) => ({91      encrypt: (pt: Uint8Array) => pt,92      decrypt: (ct: Uint8Array) => ct,93      handshakeHash: FAKE_HANDSHAKE_HASH,94    })),95    performInitiatorAuth: vi.fn(async () => undefined),96  };97});9899function makeDeps(overrides: Partial<CodePairingDeps> = {}): {100  deps: CodePairingDeps;101  persisted: PairedDevice[];102  sockets: ReturnType<typeof makeFakeSocket>[];103} {104  const persisted: PairedDevice[] = [];105  const sockets: ReturnType<typeof makeFakeSocket>[] = [];106  const deps: CodePairingDeps = {107    openSocket: vi.fn(async () => {108      // default: ACK then a PAIR_IDENTITY response109      const s = makeFakeSocket([110        enc({ type: "PEACH_HELLO_ACK", ephemeralPublicKeyHex: PEER_EPHEMERAL_HEX }),111        enc({112          type: "PAIR_IDENTITY",113          device_id: "android-001",114          device_name: "Pixel 8",115          device_type: "android",116          long_term_public_key_hex: PHONE_LONGTERM_HEX,117          ws_port: 49142,118          relay_url: "wss://relay.peachpasswords.com",119        }),120      ]);121      sockets.push(s);122      return s.sock;123    }),124    getLocalIdentity: vi.fn(async () => ({125      identity: OUR_IDENTITY,126      privateKey: OUR_PRIVATE_KEY,127      publicKey: OUR_PUBLIC_KEY,128    })),129    getRelayUrl: vi.fn(async () => "wss://relay.peachpasswords.com"),130    persistDevice: vi.fn(async (d: PairedDevice) => { persisted.push(d); }),131    ...overrides,132  };133  return { deps, persisted, sockets };134}135136function makeCallbacks(): {137  cb: CodePairingCallbacks;138  sas: { value?: string };139  errors: string[];140  completed: PairedDevice[];141} {142  const sas: { value?: string } = {};143  const errors: string[] = [];144  const completed: PairedDevice[] = [];145  const cb: CodePairingCallbacks = {146    onSasReady: (s) => { sas.value = s; },147    onError: (e) => { errors.push(e); },148    onComplete: (d) => { completed.push(d); },149  };150  return { cb, sas, errors, completed };151}152153beforeEach(() => {154  vi.clearAllMocks();155});156157// ── specs ────────────────────────────────────────────────────────────────158159describe("pairWithCode", () => {160  it("dials the coded endpoint and sends its token in PEACH_HELLO", async () => {161    const { deps, sockets } = makeDeps();162    const { cb } = makeCallbacks();163164    await pairWithCode(PHONE_CODE, cb, deps, async () => true);165166    expect(deps.openSocket).toHaveBeenCalledWith("192.168.4.77", 51555);167    const firstFrame = dec(sockets[0].sent[0]);168    expect(firstFrame).toEqual({ type: "PEACH_HELLO", token: "deadbeef" });169  });170171  it("treats a socket close without PEACH_HELLO_ACK as invalid_code", async () => {172    // The listener sends NO error frame on a wrong/expired code — it SILENTLY173    // CLOSES the socket and rotates the code. So the174    // absence of a PEACH_HELLO_ACK *is* the wrong-code signal. (This replaces175    // the original brief's bogus PEACH_HELLO_ERROR test — no such frame exists.)176    const closeImmediately = makeFakeSocket([null]); // close, no data177    const { deps } = makeDeps({178      openSocket: vi.fn(async () => closeImmediately.sock),179    });180    const { cb, errors, completed } = makeCallbacks();181182    await pairWithCode(PHONE_CODE, cb, deps, async () => true);183184    expect(errors).toEqual(["invalid_code"]);185    expect(completed).toHaveLength(0);186    expect(deps.persistDevice).not.toHaveBeenCalled();187  });188189  it("derives the SAS via the real derivePairingSAS — KAT 0fbab8cd… → 895245", () => {190    // Cross-impl KAT pinned in peach-sync (pairing.zig:275-279): the handshake191    // hash beginning 0f ba b8 cd yields SAS "895245". 0x0fbab8cd = 263895245;192    // 263895245 mod 1_000_000 = 895245.193    const hash = Uint8Array.from([194      0x0f, 0xba, 0xb8, 0xcd, ...new Array(28).fill(0),195    ]);196    expect(derivePairingSAS(hash)).toBe("895245");197  });198199  it("surfaces that same SAS through the pairing flow", async () => {200    // FAKE_HANDSHAKE_HASH starts 0fbab8cd, so onSasReady must report 895245.201    const { deps } = makeDeps();202    const { cb, sas } = makeCallbacks();203204    await pairWithCode(PHONE_CODE, cb, deps, async () => true);205206    expect(sas.value).toBe("895245");207  });208209  it("persists the phone identity on SAS confirm", async () => {210    const { deps, persisted } = makeDeps();211    const { cb, completed, errors } = makeCallbacks();212213    await pairWithCode(PHONE_CODE, cb, deps, async () => true);214215    expect(errors).toHaveLength(0);216    expect(persisted).toHaveLength(1);217    expect(persisted[0].deviceType).toBe("android");218    expect(persisted[0].deviceId).toBe("android-001");219    expect(persisted[0].longTermPublicKeyHex).toBe(PHONE_LONGTERM_HEX);220    expect(persisted[0].trustSource).toBe("direct");221    expect(persisted[0].wsPort).toBe(49142);222    expect(persisted[0].relayUrl).toBe("wss://relay.peachpasswords.com");223    expect(persisted[0].rendezvousSecretHex).toMatch(/^[0-9a-f]{64}$/);224    expect(completed).toHaveLength(1);225  });226227  it("proves possession before accepting the peer identity", async () => {228    const { performInitiatorAuth } = await import("../shared/noise-js");229    const { deps } = makeDeps();230    const { cb, errors } = makeCallbacks();231232    await pairWithCode(PHONE_CODE, cb, deps, async () => true);233234    expect(errors).toHaveLength(0);235    expect(performInitiatorAuth).toHaveBeenCalledTimes(1);236    expect(performInitiatorAuth).toHaveBeenCalledWith(237      expect.anything(),238      OUR_PRIVATE_KEY,239      OUR_PUBLIC_KEY,240      expect.any(Uint8Array),241      expect.any(Function),242      expect.any(Function),243    );244  });245246  it("rejects a PAIR_IDENTITY that is not bound to the Noise responder key", async () => {247    const { deps, persisted } = makeDeps({248      openSocket: vi.fn(async () => makeFakeSocket([249        enc({ type: "PEACH_HELLO_ACK", ephemeralPublicKeyHex: PEER_EPHEMERAL_HEX }),250        enc({251          type: "PAIR_IDENTITY",252          device_id: "attacker",253          device_name: "Wrong key",254          device_type: "android",255          long_term_public_key_hex: "f".repeat(64),256          ws_port: 49142,257        }),258      ]).sock),259    });260    const { cb, errors } = makeCallbacks();261262    await pairWithCode(PHONE_CODE, cb, deps, async () => true);263264    expect(errors).toEqual(["handshake_failed"]);265    expect(persisted).toHaveLength(0);266  });267268  it("aborts with sas_mismatch and persists nothing when the user rejects", async () => {269    const { deps, persisted } = makeDeps();270    const { cb, errors } = makeCallbacks();271272    await pairWithCode(PHONE_CODE, cb, deps, async () => false);273274    expect(errors).toEqual(["sas_mismatch"]);275    expect(persisted).toHaveLength(0);276    expect(deps.persistDevice).not.toHaveBeenCalled();277  });278279  it("includes vault_id in the outbound PAIR_IDENTITY (Change 1)", async () => {280    const { deps, sockets } = makeDeps();281    const { cb } = makeCallbacks();282283    await pairWithCode(PHONE_CODE, cb, deps, async () => true);284285    // sent[0] = PEACH_HELLO (plaintext); sent[1] = our PAIR_IDENTITY286    // (encrypt is identity in the mock, so it decodes directly).287    const ourPairIdentity = dec(sockets[0].sent[1]);288    expect(ourPairIdentity.type).toBe("PAIR_IDENTITY");289    expect(ourPairIdentity.vault_id).toBe(OUR_IDENTITY.vaultId);290  });291292  it("reports vault_locked when local identity is unavailable", async () => {293    const { deps } = makeDeps({294      getLocalIdentity: vi.fn(async () => { throw new Error("vault_locked"); }),295    });296    const { cb, errors } = makeCallbacks();297298    await pairWithCode(PHONE_CODE, cb, deps, async () => true);299300    expect(errors).toEqual(["vault_locked"]);301    expect(deps.openSocket).not.toHaveBeenCalled();302  });303});304305// ── pairing-code path (the phone is the listener) ──────────────────────────306307/** Deps whose socket replays an Android peer's ACK + PAIR_IDENTITY. */308function makePhoneDeps(deviceType: string | undefined = "android") {309  const identity: Record<string, unknown> = {310    type: "PAIR_IDENTITY",311    device_id: "android-001",312    device_name: "Pixel 8",313    long_term_public_key_hex: PHONE_LONGTERM_HEX,314    ws_port: 49142,315    relay_url: "wss://relay.peachpasswords.com",316  };317  identity.device_type = deviceType;318  return makeDeps({319    openSocket: vi.fn(async () => makeFakeSocket([320      enc({ type: "PEACH_HELLO_ACK", ephemeralPublicKeyHex: PEER_EPHEMERAL_HEX }),321      enc(identity),322    ]).sock),323  });324}325326describe("pairWithCode — pairing code", () => {327  it("dials the address in the code", async () => {328    const { deps } = makePhoneDeps();329    const { cb, errors } = makeCallbacks();330331    await pairWithCode(PHONE_CODE, cb, deps, async () => true);332333    expect(errors).toHaveLength(0);334    expect(deps.openSocket).toHaveBeenCalledWith("192.168.4.77", 51555);335  });336337  it("presents the token as hex in the plaintext hello, not a 6-digit code", async () => {338    const sockets: ReturnType<typeof makeFakeSocket>[] = [];339    const { deps } = makeDeps({340      openSocket: vi.fn(async () => {341        const s = makeFakeSocket([342          enc({ type: "PEACH_HELLO_ACK", ephemeralPublicKeyHex: PEER_EPHEMERAL_HEX }),343          enc({344            type: "PAIR_IDENTITY",345            device_id: "android-001",346            device_name: "Pixel 8",347            device_type: "android",348            long_term_public_key_hex: PHONE_LONGTERM_HEX,349            ws_port: 49142,350            relay_url: "wss://relay.peachpasswords.com",351          }),352        ]);353        sockets.push(s);354        return s.sock;355      }),356    });357    const { cb } = makeCallbacks();358359    await pairWithCode(PHONE_CODE, cb, deps, async () => true);360361    const hello = dec(sockets[0].sent[0]);362    expect(hello.type).toBe("PEACH_HELLO");363    expect(hello.token).toBe("deadbeef");364    expect(hello.code).toBeUndefined();365  });366367  it("persists the phone with the device type it announced", async () => {368    const { deps, persisted } = makePhoneDeps();369    const { cb, completed } = makeCallbacks();370371    await pairWithCode(PHONE_CODE, cb, deps, async () => true);372373    expect(persisted).toHaveLength(1);374    expect(persisted[0].deviceType).toBe("android");375    expect(persisted[0].deviceId).toBe("android-001");376    expect(persisted[0].longTermPublicKeyHex).toBe(PHONE_LONGTERM_HEX);377    expect(persisted[0].trustSource).toBe("direct");378    expect(persisted[0].wsPort).toBe(49142);379    expect(completed).toHaveLength(1);380  });381382  it("rejects a peer that omits its device type", async () => {383    const { deps, persisted } = makePhoneDeps("");384    const { cb, errors } = makeCallbacks();385386    await pairWithCode(PHONE_CODE, cb, deps, async () => true);387388    expect(errors).toEqual(["handshake_failed"]);389    expect(persisted).toHaveLength(0);390  });391392  it("caches the coded IP for the next sync round", async () => {393    const cacheLastKnownIp = vi.fn(async () => undefined);394    const { deps } = makePhoneDeps();395    deps.cacheLastKnownIp = cacheLastKnownIp;396    const { cb } = makeCallbacks();397398    await pairWithCode(PHONE_CODE, cb, deps, async () => true);399400    expect(cacheLastKnownIp).toHaveBeenCalledWith(PHONE_LONGTERM_HEX, "192.168.4.77");401  });402403  it("reports no_host_found when the coded endpoint refuses the connection", async () => {404    const { deps } = makeDeps({405      openSocket: vi.fn(async () => { throw new Error("ECONNREFUSED"); }),406    });407    const { cb, errors } = makeCallbacks();408409    await pairWithCode(PHONE_CODE, cb, deps, async () => true);410411    expect(errors).toEqual(["no_host_found"]);412    expect(deps.persistDevice).not.toHaveBeenCalled();413  });414415  it("still aborts on SAS rejection — the token is not the security boundary", async () => {416    const { deps, persisted } = makePhoneDeps();417    const { cb, errors } = makeCallbacks();418419    await pairWithCode(PHONE_CODE, cb, deps, async () => false);420421    expect(errors).toEqual(["sas_mismatch"]);422    expect(persisted).toHaveLength(0);423  });424});