Function buildStealthScript

browse/src/stealth.ts:82–249

(hw: HostProfile)

 * defineProperty getters are covered by its native-code lie.
 */
export function buildStealthScript(hw: HostProfile): string {
  return `(() => {
  // ──── Function.prototype.toString Proxy (must run first) ────
  // Make every patched getter / function below report
  // 'function NAME() { [native code] }' at every recursion depth.
  // Defeats fn.toString.toString.toString() integrity checks.
  const patchedFns = new WeakSet();
  const nativeToString = Function.prototype.toString;
  const toStringProxy = new Proxy(nativeToString, {
    apply(target, thisArg, args) {
      if (patchedFns.has(thisArg)) {
        const name = (thisArg && thisArg.name) || '';
        return 'function ' + name + '() { [native code] }';
      }
      return Reflect.apply(target, thisArg, args);
    },
  });
  Object.defineProperty(Function.prototype, 'toString', {
    value: toStringProxy, writable: true, configurable: true,
  });
  const markNative = (fn, name) => {
    if (name) {
      try { Object.defineProperty(fn, 'name', { value: name }); } catch {}
    }
    patchedFns.add(fn);
    return fn;
  };

  // ──── navigator.webdriver (canonical mask, kept from D7) ────
  try {
    const webdriverGetter = markNative(function() { return false; }, 'get webdriver');
    Object.defineProperty(navigator, 'webdriver', { get: webdriverGetter, configurable: true });
  } catch {}

  // ──── window.chrome.* restoration ────
  // Real Chrome ships these objects with rich enum / method shape.
  // Headless Chromium / Playwright's launch strips them. Their absence
  // is a universally-checked tell (verified in Cloudflare + DataDome
  // RE catalogs). We don't try to perfectly mimic — we ship plausible
  // shape with native-code-looking methods.
  try {
    if (!('chrome' in window)) {
      window.chrome = {};
    }
    const chrome = window.chrome;
    if (!chrome.runtime) {
      chrome.runtime = {
        OnInstalledReason: { CHROME_UPDATE: 'chrome_update', INSTALL: 'install',
                            SHARED_MODULE_UPDATE: 'shared_module_update', UPDATE: 'update' },
        OnRestartRequiredReason: { APP_UPDATE: 'app_update', OS_UPDATE: 'os_update', PERIODIC: 'periodic' },
        PlatformArch: { ARM: 'arm', ARM64: 'arm64', MIPS: 'mips', MIPS64: 'mips64',
                       X86_32: 'x86-32', X86_64: 'x86-64' },
        PlatformNaclArch: { ARM: 'arm', MIPS: 'mips', MIPS64: 'mips64',
                           X86_32: 'x86-32', X86_64: 'x86-64' },
        PlatformOs: { ANDROID: 'android', CROS: 'cros', LINUX: 'linux',
                     MAC: 'mac', OPENBSD: 'openbsd', WIN: 'win' },
        RequestUpdateCheckStatus: { NO_UPDATE: 'no_update', THROTTLED: 'throttled',
                                   UPDATE_AVAILABLE: 'update_available' },