Filter unsupported tracker URLs from magnets

Author: TurboTheTurtle

src/base/bittorrent/torrentdescriptor.cpp

@@ -28,6 +28,9 @@
 
 #include "torrentdescriptor.h"
 
+#include <utility>
+#include <vector>
+
 #include <libtorrent/load_torrent.hpp>
 #include <libtorrent/magnet_uri.hpp>
 #include <libtorrent/torrent_info.hpp>
@@ -84,6 +87,40 @@ namespace
 
         return limits;
     }
+
+    bool isSupportedTrackerURL(const QString &url)
+    {
+        const QUrl trackerURL {url};
+        if (!trackerURL.isValid() || trackerURL.host().isEmpty())
+            return false;
+
+        const QString scheme = trackerURL.scheme();
+        return ((scheme == u"http") || (scheme == u"https") || (scheme == u"udp"));
+    }
+
+    void removeUnsupportedTrackers(lt::add_torrent_params &params)
+    {
+        if (params.trackers.empty())
+            return;
+
+        std::vector<std::string> trackers;
+        std::vector<int> trackerTiers;
+        trackers.reserve(params.trackers.size());
+        trackerTiers.reserve(params.trackers.size());
+
+        for (std::size_t i = 0; i < params.trackers.size(); ++i)
+        {
+            const QString tracker = QString::fromStdString(params.trackers[i]);
+            if (!isSupportedTrackerURL(tracker))
+                continue;
+
+            trackers.push_back(params.trackers[i]);
+            trackerTiers.push_back((i < params.tracker_tiers.size()) ? params.tracker_tiers[i] : 0);
+        }
+
+        params.trackers = std::move(trackers);
+        params.tracker_tiers = std::move(trackerTiers);
+    }
 }
 
 const int TORRENTDESCRIPTOR_TYPEID = qRegisterMetaType<BitTorrent::TorrentDescriptor>();
@@ -161,6 +198,8 @@ catch (const lt::system_error &err)
 BitTorrent::TorrentDescriptor::TorrentDescriptor(lt::add_torrent_params ltAddTorrentParams)
     : m_ltAddTorrentParams {std::move(ltAddTorrentParams)}
 {
+    removeUnsupportedTrackers(m_ltAddTorrentParams);
+
     if (m_ltAddTorrentParams.ti && m_ltAddTorrentParams.ti->is_valid())
     {
         m_info.emplace(*m_ltAddTorrentParams.ti);

test/CMakeLists.txt

@@ -8,6 +8,7 @@ include_directories("../src")
 set(testFiles
     testalgorithm.cpp
     testbittorrentpeeraddress.cpp
+    testbittorrenttorrentdescriptor.cpp
     testbittorrenttrackerentry.cpp
     testconceptsexplicitlyconvertibleto.cpp
     testconceptsstringable.cpp

test/testbittorrenttorrentdescriptor.cpp

@@ -0,0 +1,70 @@
+/*
+ * Bittorrent Client using Qt and libtorrent.
+ * Copyright (C) 2026  Andy Ye
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * In addition, as a special exception, the copyright holders give permission to
+ * link this program with the OpenSSL project's "OpenSSL" library (or with
+ * modified versions of it that use the same license as the "OpenSSL" library),
+ * and distribute the linked executables. You must obey the GNU General Public
+ * License in all respects for all of the code used other than "OpenSSL".  If you
+ * modify file(s), you may extend this exception to your version of the file(s),
+ * but you are not obligated to do so. If you do not wish to do so, delete this
+ * exception statement from your version.
+ */
+
+#include <QObject>
+#include <QTest>
+
+#include "base/bittorrent/torrentdescriptor.h"
+#include "base/bittorrent/trackerentry.h"
+#include "base/global.h"
+
+class TestBittorrentTorrentDescriptor final : public QObject
+{
+    Q_OBJECT
+    Q_DISABLE_COPY_MOVE(TestBittorrentTorrentDescriptor)
+
+public:
+    TestBittorrentTorrentDescriptor() = default;
+
+private slots:
+    void testParseMagnetFiltersUnsupportedTrackers() const
+    {
+        const QString magnet =
+                u"magnet:?xt=urn:btih:c58645e2e922428dceb1f98f51ffa424810570f0"
+                "&tr=http%3A%2F%2Ftracker.example.com%2Fannounce"
+                "&tr=udp%3A%2F%2Ftracker.example.com%3A1337%2Fannounce"
+                "&tr=%3C!DOCTYPE%20html%3E%3Chtml%3E"
+                "&tr=ftp%3A%2F%2Ftracker.example.com%2Fannounce"
+                "&tr=313131"_s;
+
+        const auto parseResult = BitTorrent::TorrentDescriptor::parse(magnet);
+        QVERIFY(parseResult);
+
+        const QList<BitTorrent::TrackerEntry> trackers = parseResult.value().trackers();
+        QCOMPARE(trackers.size(), 2);
+        QCOMPARE(trackers.at(0).url, u"http://tracker.example.com/announce"_s);
+        QCOMPARE(trackers.at(1).url, u"udp://tracker.example.com:1337/announce"_s);
+
+        const lt::add_torrent_params &nativeParams = parseResult.value().ltAddTorrentParams();
+        QCOMPARE(nativeParams.trackers.size(), 2);
+        QCOMPARE(nativeParams.tracker_tiers.size(), 2);
+    }
+};
+
+QTEST_APPLESS_MAIN(TestBittorrentTorrentDescriptor)
+#include "testbittorrenttorrentdescriptor.moc"