Add check for Content-Type when downloading tracker list

src/base/net/downloadhandlerimpl.cpp

@@ -143,6 +143,7 @@ void Net::DownloadHandlerImpl::processFinishedDownload()
 #else
     m_result.data = m_reply->readAll();
 #endif
+    m_result.contentType = m_reply->header(QNetworkRequest::ContentTypeHeader).toString();
 
     if (m_downloadRequest.saveToFile())
     {

src/base/net/downloadmanager.h

@@ -107,6 +107,7 @@ namespace Net
         QByteArray data;
         Path filePath;
         QString magnetURI;
+        QString contentType;
     };
 
     class DownloadHandler : public QObject

src/gui/optionsdialog.cpp

@@ -83,6 +83,7 @@
 #include "watchedfolderoptionsdialog.h"
 #include "watchedfoldersmodel.h"
 #include "webui/webui.h"
+#include "base/net/downloadmanager.h"
 
 #ifndef DISABLE_WEBUI
 #include "base/net/dnsupdater.h"
@@ -1229,8 +1230,42 @@ void OptionsDialog::saveBittorrentTabOptions() const
     session->setAddTrackersEnabled(m_ui->checkEnableAddTrackers->isChecked());
     session->setAdditionalTrackers(m_ui->textTrackers->toPlainText());
 
+    auto enabledAddTrackers = m_ui->checkAddTrackersFromURL->isChecked();
+    auto url = m_ui->textTrackersURL->text();
+    if (!url.isEmpty() && enabledAddTrackers)
+    {
+        Net::DownloadManager::instance()->download(url, Preferences::instance()->useProxyForGeneralPurposes()
+            , this, &OptionsDialog::onAddTrackersDownload);
+    }
+    else
+    {
+        session->setAddTrackersFromURLEnabled(enabledAddTrackers);
+        session->setAdditionalTrackersURL(url);
+    }
+}
+
+void OptionsDialog::onAddTrackersDownload(const Net::DownloadResult &result)
+{
+    if (result.status != Net::DownloadStatus::Success)
+    {
+        QMessageBox::warning(this, tr("Download trackers list error")
+            , tr("Error occurred when downloading the trackers list. Reason: \"%1\"").arg(result.errorString));
+        return;
+    }
+
+    if (!result.contentType.contains(u"text/plain"_s, Qt::CaseInsensitive))
+    {
+        QMessageBox::warning(this, tr("Download trackers list error")
+            , tr("The content type of the downloaded file is not plain text. Content-Type: \"%1\"").arg(result.contentType));
+        return;
+    }
+
+    auto *session = BitTorrent::Session::instance();
+
     session->setAddTrackersFromURLEnabled(m_ui->checkAddTrackersFromURL->isChecked());
     session->setAdditionalTrackersURL(m_ui->textTrackersURL->text());
+
+    return;
 }
 
 void OptionsDialog::loadRSSTabOptions()

src/gui/optionsdialog.h

@@ -34,6 +34,7 @@
 #include "base/pathfwd.h"
 #include "base/settingvalue.h"
 #include "guiapplicationcomponent.h"
+#include "base/net/downloadmanager.h"
 
 class QListWidgetItem;
 
@@ -137,9 +138,12 @@ private slots:
     void loadRSSTabOptions();
     void saveRSSTabOptions() const;
 
+    void onAddTrackersDownload(const Net::DownloadResult &result);
+
     void loadSearchTabOptions();
     void saveSearchTabOptions() const;
 
+
 #ifndef DISABLE_WEBUI
     void loadWebUITabOptions();
     void saveWebUITabOptions() const;

src/gui/trackersadditiondialog.cpp

@@ -74,14 +74,35 @@ TrackersAdditionDialog::~TrackersAdditionDialog()
     delete m_ui;
 }
 
+int TrackersAdditionDialog::isValidEndpoint(const QStringView &endpoint) const
+{
+    if (endpoint.isEmpty())
+        return 0;
+    QUrl url(endpoint.toString());
+    if (!url.isValid())
+        return 0;
+    if (url.scheme().isEmpty())
+        return 0;
+    if (url.host().isEmpty())
+        return 0;
+    return 1;
+}
+
 void TrackersAdditionDialog::onAccepted() const
 {
     const QList<BitTorrent::TrackerEntryStatus> currentTrackers = m_torrent->trackers();
     const int baseTier = !currentTrackers.isEmpty() ? (currentTrackers.last().tier + 1) : 0;
 
     QList<BitTorrent::TrackerEntry> entries = BitTorrent::parseTrackerEntries(m_ui->textEditTrackersList->toPlainText());
-    for (BitTorrent::TrackerEntry &entry : entries)
+    for (BitTorrent::TrackerEntry &entry : entries) {
+        auto isValid = isValidEndpoint(entry.url);
+        if (!isValid)
+        {
+            QMessageBox::warning(const_cast<TrackersAdditionDialog *>(this), tr("Invalid tracker URL"), tr("The tracker URL \"%1\" is invalid").arg(entry.url));
+            return;
+        }
         entry.tier = Utils::Number::clampingAdd(entry.tier, baseTier);
+    }
 
     m_torrent->addTrackers(entries);
 }
@@ -116,6 +137,13 @@ void TrackersAdditionDialog::onTorrentListDownloadFinished(const Net::DownloadRe
         return;
     }
 
+    if (!result.contentType.contains(u"text/plain"_s, Qt::CaseInsensitive))
+    {
+        QMessageBox::warning(this, tr("Download trackers list error")
+            , tr("The content type of the downloaded file is not plain text. Content-Type: \"%1\"").arg(result.contentType));
+        return;
+    }
+
     // Add fetched trackers to the list
     const QString existingText = m_ui->textEditTrackersList->toPlainText();
     if (!existingText.isEmpty() && !existingText.endsWith(u'\n'))

src/gui/trackersadditiondialog.h

@@ -65,6 +65,7 @@ private slots:
 private:
     void saveSettings();
     void loadSettings();
+    int isValidEndpoint(const QStringView &endpoint) const;
 
     Ui::TrackersAdditionDialog *m_ui = nullptr;
     BitTorrent::Torrent *const m_torrent = nullptr;