Stop synchronisation when behind a captive portal

Fixes: #11533

src/gui/accountsettings.cpp

@@ -491,7 +491,11 @@ void AccountSettings::slotAccountStateChanged()
         break;
     }
     case AccountState::Connecting:
-        showConnectionLabel(tr("Connecting to: %1.").arg(server));
+        if (NetworkInformation::instance()->isBehindCaptivePortal()) {
+            showConnectionLabel(tr("Captive portal prevents connections to %1.").arg(server));
+        } else {
+            showConnectionLabel(tr("Connecting to: %1.").arg(server));
+        }
         break;
     case AccountState::ConfigurationError:
         showConnectionLabel(tr("Server configuration error: %1.")

src/gui/accountstate.cpp

@@ -146,6 +146,12 @@ AccountState::AccountState(AccountPtr account)
         }
     });
 
+    connect(NetworkInformation::instance(), &NetworkInformation::isBehindCaptivePortalChanged, this, [this](bool) {
+        // A direct connect is not possible, because then the state parameter of `isBehindCaptivePortalChanged`
+        // would become the `verifyServerState` argument to `checkConnectivity`.
+        QTimer::singleShot(0, this, [this] { checkConnectivity(false); });
+    });
+
     // as a fallback and to recover after server issues we also poll
     auto timer = new QTimer(this);
     timer->setInterval(ConnectionValidator::DefaultCallingInterval);
@@ -166,6 +172,22 @@ AccountState::AccountState(AccountPtr account)
         ownCloudGui::raise();
         msgBox->open();
     });
+
+
+    connect(NetworkInformation::instance(), &NetworkInformation::isBehindCaptivePortalChanged, this, [this](bool onoff) {
+        if (onoff) {
+            _queueGuard.block();
+        } else {
+            // TODO: empty queue?
+            _queueGuard.unblock();
+        }
+    });
+    if (NetworkInformation::instance()->isBehindCaptivePortal()) {
+        _queueGuard.block();
+    } else {
+        // TODO: empty queue?
+        _queueGuard.unblock();
+    }
 }
 
 AccountState::~AccountState() { }
@@ -362,6 +384,9 @@ void AccountState::checkConnectivity(bool blockJobs)
         this, &AccountState::slotConnectionValidatorResult);
 
     connect(_connectionValidator, &ConnectionValidator::sslErrors, this, [blockJobs, this](const QList<QSslError> &errors) {
+        if (NetworkInformation::instance()->isBehindCaptivePortal()) {
+            return;
+        }
         if (!_tlsDialog) {
             // ignore errors for already accepted certificates
             auto filteredErrors = _account->accessManager()->filterSslErrors(errors);
@@ -477,6 +502,7 @@ void AccountState::slotConnectionValidatorResult(ConnectionValidator::Status sta
         setState(Connected);
         break;
     case ConnectionValidator::Undefined:
+        [[fallthrough]];
     case ConnectionValidator::NotConfigured:
         setState(Disconnected);
         break;
@@ -492,6 +518,7 @@ void AccountState::slotConnectionValidatorResult(ConnectionValidator::Status sta
         setState(NetworkError);
         break;
     case ConnectionValidator::CredentialsWrong:
+        [[fallthrough]];
     case ConnectionValidator::CredentialsNotReady:
         slotInvalidCredentials();
         break;
@@ -509,6 +536,9 @@ void AccountState::slotConnectionValidatorResult(ConnectionValidator::Status sta
     case ConnectionValidator::Timeout:
         setState(NetworkError);
         break;
+    case ConnectionValidator::CaptivePortal:
+        setState(Connecting);
+        break;
     }
 }
 

src/gui/connectionvalidator.cpp

@@ -14,6 +14,7 @@
 #include "gui/connectionvalidator.h"
 #include "gui/clientproxy.h"
 #include "gui/fetchserversettings.h"
+#include "gui/networkinformation.h"
 #include "gui/tlserrordialog.h"
 #include "libsync/account.h"
 #include "libsync/cookiejar.h"
@@ -132,7 +133,7 @@ void ConnectionValidator::slotCheckServerAndAuth()
                 reportResult(Timeout);
                 return;
             case QNetworkReply::SslHandshakeFailedError:
-                reportResult(SslError);
+                reportResult(NetworkInformation::instance()->isBehindCaptivePortal() ? CaptivePortal : SslError);
                 return;
             case QNetworkReply::TooManyRedirectsError:
                 reportResult(MaintenanceMode);
@@ -214,7 +215,7 @@ void ConnectionValidator::slotAuthFailed(QNetworkReply *reply)
 
     if (reply->error() == QNetworkReply::SslHandshakeFailedError) {
         _errors << job->errorStringParsingBody();
-        stat = SslError;
+        stat = NetworkInformation::instance()->isBehindCaptivePortal() ? CaptivePortal : SslError;
 
     } else if (reply->error() == QNetworkReply::AuthenticationRequiredError
         || !_account->credentials()->stillValid(reply)) {

src/gui/connectionvalidator.h

@@ -101,9 +101,10 @@ class OWNCLOUDGUI_EXPORT ConnectionValidator : public QObject
         ServiceUnavailable, // 503 on authed request
         MaintenanceMode, // maintenance enabled in status.php
         Timeout, // actually also used for other errors on the authed request
-        ClientUnsupported // The server blocks us as an unsupported client
+        ClientUnsupported, // The server blocks us as an unsupported client
+        CaptivePortal, // We're stuck behind a captive portal and (will) get SSL certificate problems
     };
-    Q_ENUM(Status);
+    Q_ENUM(Status)
 
     // How often should the Application ask this object to check for the connection?
     static constexpr auto DefaultCallingInterval = std::chrono::seconds(62);

src/gui/networkinformation.cpp

@@ -55,6 +55,7 @@ void NetworkInformation::initialize()
     if (auto qni = QNetworkInformation::instance()) {
         connect(qni, &QNetworkInformation::isMeteredChanged, _instance, &NetworkInformation::isMeteredChanged);
         connect(qni, &QNetworkInformation::reachabilityChanged, _instance, &NetworkInformation::reachabilityChanged);
+        connect(qni, &QNetworkInformation::isBehindCaptivePortalChanged, _instance, &NetworkInformation::slotIsBehindCaptivePortalChanged);
     }
 }
 
@@ -80,3 +81,46 @@ bool NetworkInformation::supports(Features features) const
 
     return false;
 }
+
+bool NetworkInformation::isForcedCaptivePortal() const
+{
+    return _forcedCaptivePortal;
+}
+
+void NetworkInformation::setForcedCaptivePortal(bool onoff)
+{
+    if (_forcedCaptivePortal != onoff) {
+        _forcedCaptivePortal = onoff;
+        qCDebug(lcNetInfo) << "Switching forced captive portal to" << onoff;
+
+        bool behindCaptivePortal = false;
+
+        if (auto *qNetInfo = QNetworkInformation::instance()) {
+            behindCaptivePortal = qNetInfo->isBehindCaptivePortal();
+        }
+
+        if (behindCaptivePortal != _forcedCaptivePortal) {
+            Q_EMIT isBehindCaptivePortalChanged(_forcedCaptivePortal);
+        }
+    }
+}
+
+bool NetworkInformation::isBehindCaptivePortal() const
+{
+    if (_forcedCaptivePortal) {
+        return true;
+    }
+
+    if (auto *qNetInfo = QNetworkInformation::instance()) {
+        return qNetInfo->isBehindCaptivePortal();
+    }
+
+    return false;
+}
+
+void NetworkInformation::slotIsBehindCaptivePortalChanged(bool state)
+{
+    if (!_forcedCaptivePortal) {
+        Q_EMIT isBehindCaptivePortalChanged(state);
+    }
+}

src/gui/networkinformation.h

@@ -20,6 +20,12 @@
 
 namespace OCC {
 
+/**
+ * @brief Wrapper class for QNetworkInformation
+ *
+ * This class is used instead of QNetworkInformation so we do not need to check for an instance,
+ * and to facilitate debugging by being able to force certain network states (i.e. captive portal).
+ */
 class OWNCLOUDGUI_EXPORT NetworkInformation : public QObject
 {
     Q_OBJECT
@@ -36,12 +42,22 @@ class OWNCLOUDGUI_EXPORT NetworkInformation : public QObject
 
     bool supports(Features features) const;
 
+    bool isForcedCaptivePortal() const;
+    void setForcedCaptivePortal(bool onoff);
+    bool isBehindCaptivePortal() const;
+
 Q_SIGNALS:
     void isMeteredChanged(bool isMetered);
     void reachabilityChanged(NetworkInformation::Reachability reachability);
+    void isBehindCaptivePortalChanged(bool state);
+
+private Q_SLOTS:
+    void slotIsBehindCaptivePortalChanged(bool state);
 
 private:
     static NetworkInformation *_instance;
+
+    bool _forcedCaptivePortal = false;
 };
 
 }

src/gui/owncloudgui.cpp

@@ -26,6 +26,7 @@
 #include "folderwizard/folderwizard.h"
 #include "gui/accountsettings.h"
 #include "gui/commonstrings.h"
+#include "gui/networkinformation.h"
 #include "guiutility.h"
 #include "libsync/theme.h"
 #include "logbrowser.h"
@@ -652,6 +653,11 @@ void ownCloudGui::updateContextMenu()
         debugMenu->addAction(QStringLiteral("Crash now - OC_ENFORCE()"), _app, [] { OC_ENFORCE(false); });
         debugMenu->addAction(QStringLiteral("Crash now - qFatal"), _app, [] { qFatal("la Qt fatale"); });
         debugMenu->addAction(QStringLiteral("Restart now"), _app, [] { RestartManager::requestRestart(); });
+        debugMenu->addSeparator();
+        auto captivePortalCheckbox = debugMenu->addAction(QStringLiteral("Behind Captive Portal"));
+        captivePortalCheckbox->setCheckable(true);
+        captivePortalCheckbox->setChecked(NetworkInformation::instance()->isForcedCaptivePortal());
+        connect(captivePortalCheckbox, &QAction::triggered, [](bool checked) { NetworkInformation::instance()->setForcedCaptivePortal(checked); });
     }
 
     _contextMenu->addSeparator();