qt-aad-helper/main.cpp

 
#include <QApplication>
#include <QCloseEvent>
#include <QJsonDocument>
#include <QJsonObject>
#include <QJsonValue>
#include <QMetaObject>
#include <QString>
#include <QUrl>
#include <QWebEngineNavigationRequest>
#include <QWebEnginePage>
#include <QWebEngineProfile>
#include <QWebEngineUrlRequestJob>
#include <QWebEngineUrlScheme>
#include <QWebEngineUrlSchemeHandler>
#include <QWebEngineView>
 
#include <chrono>
#include <condition_variable>
#include <cstdint>
#include <iostream>
#include <mutex>
#include <string>
#include <thread>
 
#include <winpr/file.h>
#include <winpr/handle.h>
 
#include "redirect_watcher.hpp"
 
constexpr uint32_t kDefaultTimeoutMs = 180000;
 
constexpr const char* kBrokerScheme = "ms-appx-web";
 
struct PendingResult
{
  std::mutex mtx;
  std::condition_variable cv;
  bool done = false;
  bool ok = false;
  std::string redirectUrl;
  std::string errorMessage;
};
 
class Session;
 
class AuthWindow : public QWebEngineView
{
  Q_OBJECT
  public:
  explicit AuthWindow(Session& owner);
 
  protected:
  void closeEvent(QCloseEvent* event) override;
 
  private slots:
  void onNavigationRequested(QWebEngineNavigationRequest& request);
  void onLoadFinished(bool ok);
 
  private:
  Session& session;
};
 
class Session
{
  public:
  Session() : nativeUserAgent(QWebEngineProfile::defaultProfile()->httpUserAgent().toStdString())
  {
  }
 
  bool navigate(const std::string& title, const std::string& url, const std::string& redirectUri,
                uint32_t timeoutMs, const std::string& userAgent, std::string& redirectUrl,
                std::string& error)
  {
    PendingResult pending;
    {
      std::lock_guard<std::mutex> lock(stateMtx);
      if (current)
      {
        error = "navigate_already_in_progress";
        return false;
      }
      current = &pending;
      watcher = RedirectWatcher(redirectUri);
    }
 
    const QString qtitle = QString::fromStdString(title);
    const QUrl qurl(QString::fromStdString(url));
    QMetaObject::invokeMethod(
        qApp,
        [this, qtitle, qurl, userAgent]()
        {
          if (!window)
            window = new AuthWindow(*this);
          window->setWindowTitle(qtitle);
          window->resize(800, 600);
          window->show();
          window->raise();
          window->activateWindow();
          /* QtWebEngine keeps one profile for the process' life, so an override would
           * otherwise persist after it is dropped: always set either the override or the
           * native UA captured at construction. */
          const QString ua =
              QString::fromStdString(userAgent.empty() ? nativeUserAgent : userAgent);
          QWebEngineProfile::defaultProfile()->setHttpUserAgent(ua);
          window->setUrl(qurl);
        },
        Qt::QueuedConnection);
 
    const uint32_t timeout = timeoutMs ? timeoutMs : kDefaultTimeoutMs;
    bool signalled = false;
    {
      std::unique_lock<std::mutex> lock(pending.mtx);
      signalled = pending.cv.wait_for(lock, std::chrono::milliseconds(timeout),
                                      [&] { return pending.done; });
    }
 
    {
      std::lock_guard<std::mutex> lock(stateMtx);
      /* still ours: nobody finished it (timeout) - detach the now-invalid pointer to the
       * stack-local `pending` before it goes out of scope */
      if (current == &pending)
        current = nullptr;
    }
 
    /* the popup has served its purpose once this navigate() is done, whatever the outcome -
     * hide it now rather than leaving it sitting on screen until the next navigate() (if any)
     * reuses and re-shows it. */
    QMetaObject::invokeMethod(
        qApp,
        [this]()
        {
          if (window)
            window->hide();
        },
        Qt::QueuedConnection);
 
    if (!signalled)
    {
      error = "timeout";
      return false;
    }
 
    if (!pending.ok)
    {
      error = pending.errorMessage.empty() ? "user_cancelled" : pending.errorMessage;
      return false;
    }
 
    redirectUrl = pending.redirectUrl;
    return true;
  }
 
  void cancel()
  {
    std::lock_guard<std::mutex> lock(stateMtx);
    finishCurrentLocked(false, "", "user_cancelled");
  }
 
  void quit()
  {
    {
      std::lock_guard<std::mutex> lock(stateMtx);
      finishCurrentLocked(false, "", "shutting_down");
    }
    /* the window (and the QWebEnginePage/profile reference it holds) must be gone before
     * QApplication's destructor tears down the default QWebEngineProfile, or QtWebEngine
     * warns "Release of profile requested but WebEnginePage still not deleted." Deleting it
     * here, still inside the running event loop, is what QtWebEngine expects. */
    QMetaObject::invokeMethod(
        qApp,
        [this]()
        {
          delete window;
          window = nullptr;
          qApp->quit();
        },
        Qt::QueuedConnection);
  }
 
  /* called on the UI thread by AuthWindow::onNavigationRequested. Returns true if `uri` matched
   * the pending redirect_uri (in which case the pending navigate() has been resolved and the
   * caller must reject the navigation rather than let QtWebEngine try to load it). */
  bool onNavigate(const std::string& uri)
  {
    std::lock_guard<std::mutex> lock(stateMtx);
    if (!current || !watcher.matches(uri))
      return false;
 
    std::string err;
    if (watcher.hasError(uri, err))
      finishCurrentLocked(false, "", err);
    else
      finishCurrentLocked(true, uri, "");
    return true;
  }
 
  /* called on the UI thread by AuthWindow::closeEvent, e.g. the user closed the popup */
  void onWindowClosed()
  {
    std::lock_guard<std::mutex> lock(stateMtx);
    finishCurrentLocked(false, "", "user_cancelled");
  }
 
  private:
  /* caller must hold stateMtx */
  void finishCurrentLocked(bool ok, const std::string& redirectUrl, const std::string& err)
  {
    if (!current)
      return;
    {
      std::lock_guard<std::mutex> lock(current->mtx);
      current->done = true;
      current->ok = ok;
      current->redirectUrl = redirectUrl;
      current->errorMessage = err;
    }
    current->cv.notify_all();
    current = nullptr;
  }
 
  std::mutex stateMtx;
  PendingResult* current = nullptr;
  RedirectWatcher watcher{ std::string() };
  AuthWindow* window = nullptr; /* UI thread only */
  std::string nativeUserAgent;
};
 
AuthWindow::AuthWindow(Session& owner) : session(owner)
{
  connect(page(), &QWebEnginePage::navigationRequested, this, &AuthWindow::onNavigationRequested);
  connect(this, &QWebEngineView::loadFinished, this, &AuthWindow::onLoadFinished);
}
 
void AuthWindow::onNavigationRequested(QWebEngineNavigationRequest& request)
{
  if (session.onNavigate(request.url().toString().toStdString()))
    request.reject();
}
 
void AuthWindow::onLoadFinished(bool ok)
{
  std::cout << "[qt-aad-helper] loaded " << url().toString().toStdString()
            << (ok ? "" : " (failed)") << std::endl;
}
 
void AuthWindow::closeEvent(QCloseEvent* event)
{
  session.onWindowClosed();
  QWebEngineView::closeEvent(event);
}
 
class BrokerSchemeHandler : public QWebEngineUrlSchemeHandler
{
  public:
  explicit BrokerSchemeHandler(Session& owner) : session(owner)
  {
  }
 
  void requestStarted(QWebEngineUrlRequestJob* job) override
  {
    session.onNavigate(job->requestUrl().toString().toStdString());
    job->fail(QWebEngineUrlRequestJob::RequestAborted);
  }
 
  private:
  Session& session;
};
 
namespace
{
 
  /* the JSON-RPC channel: handles imported from the --cmdInFd=/--cmdOutFd= command line arguments
   * (see main()), not stdin/stdout - so this helper's own stdio stays free for its normal
   * diagnostic output (Qt/Chromium warnings, WLog, etc.) instead of colliding with the protocol.
   */
  HANDLE g_cmdIn = nullptr;
  HANDLE g_cmdOut = nullptr;
 
  bool writeLine(const std::string& line)
  {
    std::string data = line;
    data += "\n";
 
    size_t written = 0;
    while (written < data.size())
    {
      DWORD dwWritten = 0;
      if (!WriteFile(g_cmdOut, data.data() + written,
                     static_cast<DWORD>(data.size() - written), &dwWritten, nullptr) ||
          (dwWritten == 0))
        return false;
      written += dwWritten;
    }
    return true;
  }
 
  /* extracts one '\n'-terminated line already buffered in `buf`, if any */
  bool extractLine(std::string& buf, std::string& line)
  {
    const auto pos = buf.find('\n');
    if (pos == std::string::npos)
      return false;
    line = buf.substr(0, pos);
    buf.erase(0, pos + 1);
    return true;
  }
 
  bool readLine(std::string& buf, std::string& line)
  {
    if (extractLine(buf, line))
      return true;
 
    while (true)
    {
      char chunk[4096];
      DWORD dwRead = 0;
      if (!ReadFile(g_cmdIn, chunk, sizeof(chunk), &dwRead, nullptr) || (dwRead == 0))
        return false;
      buf.append(chunk, dwRead);
      if (extractLine(buf, line))
        return true;
    }
  }
 
  void sendLine(const std::string& line)
  {
    (void)writeLine(line);
  }
 
  void sendJson(const QJsonObject& obj)
  {
    const QJsonDocument doc(obj);
    sendLine(doc.toJson(QJsonDocument::Compact).toStdString());
  }
 
  void sendHelloResult(int64_t id)
  {
    QJsonObject result;
    result["protocol_version"] = 1;
    result["helper"] = QStringLiteral("freerdp-qt-aad-helper/1.0");
 
    QJsonObject obj;
    obj["jsonrpc"] = QStringLiteral("2.0");
    obj["id"] = static_cast<double>(id);
    obj["result"] = result;
    sendJson(obj);
  }
 
  void sendNavigateResult(int64_t id, const std::string& redirectUrl)
  {
    QJsonObject result;
    result["status"] = QStringLiteral("ok");
    result["redirect_url"] = QString::fromStdString(redirectUrl);
 
    QJsonObject obj;
    obj["jsonrpc"] = QStringLiteral("2.0");
    obj["id"] = static_cast<double>(id);
    obj["result"] = result;
    sendJson(obj);
  }
 
  void sendNullResult(int64_t id)
  {
    QJsonObject obj;
    obj["jsonrpc"] = QStringLiteral("2.0");
    obj["id"] = static_cast<double>(id);
    obj["result"] = QJsonValue();
    sendJson(obj);
  }
 
  void sendError(int64_t id, int code, const std::string& message)
  {
    QJsonObject error;
    error["code"] = code;
    error["message"] = QString::fromStdString(message);
 
    QJsonObject obj;
    obj["jsonrpc"] = QStringLiteral("2.0");
    obj["id"] = static_cast<double>(id);
    obj["error"] = error;
    sendJson(obj);
  }
 
  std::string getStringField(const QJsonObject& obj, const char* name)
  {
    const QJsonValue v = obj.value(QLatin1String(name));
    return v.isString() ? v.toString().toStdString() : std::string();
  }
 
  uint32_t getUintField(const QJsonObject& obj, const char* name, uint32_t def)
  {
    const QJsonValue v = obj.value(QLatin1String(name));
    return v.isDouble() ? static_cast<uint32_t>(v.toDouble()) : def;
  }
 
  void readerLoop(Session& session)
  {
    std::string buf;
    std::string line;
    while (readLine(buf, line))
    {
      if (line.empty())
        continue;
 
      const QJsonDocument doc = QJsonDocument::fromJson(QByteArray::fromStdString(line));
      if (!doc.isObject())
        continue;
      const QJsonObject msg = doc.object();
 
      const QJsonValue idValue = msg.value(QLatin1String("id"));
      const bool hasId = idValue.isDouble();
      const int64_t id = hasId ? static_cast<int64_t>(idValue.toDouble()) : 0;
      const std::string method = getStringField(msg, "method");
      const QJsonObject params = msg.value(QLatin1String("params")).toObject();
 
      if (method == "hello")
      {
        sendHelloResult(id);
      }
      else if (method == "navigate")
      {
        const std::string title = getStringField(params, "title");
        const std::string url = getStringField(params, "url");
        const std::string redirectUri = getStringField(params, "redirect_uri");
        const std::string userAgent = getStringField(params, "user_agent");
        const uint32_t timeoutMs = getUintField(params, "timeout_ms", kDefaultTimeoutMs);
 
        std::string redirectUrl;
        std::string error;
        if (session.navigate(title, url, redirectUri, timeoutMs, userAgent, redirectUrl,
                             error))
          sendNavigateResult(id, redirectUrl);
        else
          sendError(id, 1, error);
      }
      else if (method == "cancel")
      {
        session.cancel();
      }
      else if (method == "shutdown")
      {
        sendNullResult(id);
      }
      else if (method == "exit")
      {
        break;
      }
    }
 
    session.quit();
  }
 
} // namespace
 
int main(int argc, char* argv[])
{
  std::string cmdInArg;
  std::string cmdOutArg;
  for (int i = 1; i < argc; i++)
  {
    const std::string arg = argv[i];
    if (arg.rfind("--cmdInFd=", 0) == 0)
      cmdInArg = arg;
    else if (arg.rfind("--cmdOutFd=", 0) == 0)
      cmdOutArg = arg;
  }
 
  if (cmdInArg.empty() || cmdOutArg.empty())
  {
    std::cerr << "usage: " << (argc > 0 ? argv[0] : "freerdp-qt-aad-helper")
              << " --cmdInFd=<handle> --cmdOutFd=<handle>" << std::endl;
    return 1;
  }
 
  g_cmdIn = winpr_importHandleFromString(cmdInArg.c_str(), "--cmdInFd={}");
  g_cmdOut = winpr_importHandleFromString(cmdOutArg.c_str(), "--cmdOutFd={}");
  if (!g_cmdIn || (g_cmdIn == INVALID_HANDLE_VALUE) || !g_cmdOut ||
      (g_cmdOut == INVALID_HANDLE_VALUE))
  {
    std::cerr << "failed to import the cmdIn/cmdOut channel handles" << std::endl;
    return 1;
  }
 
  /* must be registered before QApplication is constructed. CorsEnabled adds the scheme to
   * Chromium's CORS-enabled/"web-safe" scheme list, which its network stack also consults to
   * decide whether an https: page is allowed to redirect into it - without this, Chromium
   * rejects the AAD redirect with net::ERR_UNSAFE_REDIRECT before we ever see it. LocalScheme
   * (file:-like privilege) is deliberately NOT set: that made things worse, since Chromium
   * specifically disallows network content redirecting into a local-privilege scheme. */
  QWebEngineUrlScheme brokerScheme(kBrokerScheme);
  brokerScheme.setSyntax(QWebEngineUrlScheme::Syntax::Host);
  brokerScheme.setFlags(QWebEngineUrlScheme::CorsEnabled);
  QWebEngineUrlScheme::registerScheme(brokerScheme);
 
  QApplication app(argc, argv);
  /* QApplication defaults to quitting as soon as its last top-level window (here, the popup)
   * is closed - which would call qApp->quit() straight from closeEvent(), bypassing
   * Session::quit() (and the `delete window` it does before quitting) entirely: the app would
   * exit with the AuthWindow/QWebEnginePage still alive, triggering QtWebEngine's "Release of
   * profile requested but WebEnginePage still not deleted" warning at teardown. The window is
   * deliberately kept alive (just hidden) across navigate() calls anyway - see Session's class
   * comment - so only our own explicit quit(), driven by the "exit" JSON-RPC notification,
   * should end the process. */
  app.setQuitOnLastWindowClosed(false);
 
  Session session;
  BrokerSchemeHandler brokerHandler(session);
  QWebEngineProfile::defaultProfile()->installUrlSchemeHandler(QByteArray(kBrokerScheme),
                                                               &brokerHandler);
 
  std::thread reader(readerLoop, std::ref(session));
 
  const int rc = QApplication::exec();
  reader.join();
 
  (void)CloseHandle(g_cmdIn);
  (void)CloseHandle(g_cmdOut);
  return rc;
}
 
#include "main.moc"