Block invalid file names when renaming torrent content

Relevant issues: #22426, #21899,#16906,#16834, #16271, #11276, #9085, #11340, #14728, #20412, #20337, #17049, #17752, #17469, #15378, #15227, #14908.
PR #23060.

---------

Co-authored-by: Chocobo1 <Chocobo1@users.noreply.github.com>

src/base/utils/fs.cpp

@@ -219,6 +219,60 @@ Path Utils::Fs::tempPath()
     return path;
 }
 
+// Validates a file name, where "file" refers to both files and directories in Windows and Unix-like systems.
+// Returns true if the name is valid, false if it contains empty/special names, exceeds platform-specific lengths,
+// uses reserved names, or includes forbidden characters.
+bool Utils::Fs::isValidName(const QString &name)
+{
+    // Reject empty names or special directory names (".", "..")
+    if (name.isEmpty() || (name == u"."_s) || (name == u".."_s))
+        return false;
+
+#ifdef Q_OS_WIN
+    // Windows restricts file names to 255 characters and prohibits trailing dots
+    if ((name.length() > 255) || name.endsWith(u'.'))
+        return false;
+#else
+    // Non-Windows systems limit file name lengths to 255 bytes in UTF-8 encoding
+    if (name.toUtf8().length() > 255)
+        return false;
+#endif
+
+#ifdef Q_OS_WIN
+    // Windows reserves certain names for devices, which cannot be used as file names
+    const QSet reservedNames
+    {
+        u"CON"_s, u"PRN"_s, u"AUX"_s, u"NUL"_s,
+        u"COM1"_s, u"COM2"_s, u"COM3"_s, u"COM4"_s,
+        u"COM5"_s, u"COM6"_s, u"COM7"_s, u"COM8"_s,
+        u"COM9"_s, u"COM¹"_s, u"COM²"_s, u"COM³"_s,
+        u"LPT1"_s, u"LPT2"_s, u"LPT3"_s, u"LPT4"_s,
+        u"LPT5"_s, u"LPT6"_s, u"LPT7"_s, u"LPT8"_s,
+        u"LPT9"_s, u"LPT¹"_s, u"LPT²"_s, u"LPT³"_s
+    };
+    const QString baseName = name.section(u'.', 0, 0).toUpper();
+    if (reservedNames.contains(baseName))
+        return false;
+#endif
+
+    // Check for control characters, delete character, and forward slash
+    for (const QChar &c : name)
+    {
+        const ushort unicode = c.unicode();
+        if ((unicode < 32) || (unicode == 127) || (c == u'/'))
+            return false;
+#ifdef Q_OS_WIN
+        // Windows forbids reserved characters in file names
+        if ((c == u'\\') || (c == u'<') || (c == u'>') || (c == u':') || (c == u'"') ||
+            (c == u'|') || (c == u'?') || (c == u'*'))
+            return false;
+#endif
+    }
+
+    // If none of the invalid conditions are met, the name is valid
+    return true;
+}
+
 bool Utils::Fs::isRegularFile(const Path &path)
 {
     std::error_code ec;

src/base/utils/fs.h

@@ -46,6 +46,7 @@ namespace Utils::Fs
     qint64 computePathSize(const Path &path);
     qint64 freeDiskSpaceOnPath(const Path &path);
 
+    bool isValidName(const QString &name);
     bool isRegularFile(const Path &path);
     bool isDir(const Path &path);
     bool isReadable(const Path &path);

src/gui/torrentcontentmodel.cpp

@@ -299,9 +299,16 @@ bool TorrentContentModel::setData(const QModelIndex &index, const QVariant &valu
         case TorrentContentModelItem::COL_NAME:
             {
                 const QString currentName = item->name();
-                const QString newName = value.toString();
+                const QString newName = value.toString().trimmed();
+
                 if (currentName != newName)
                 {
+                    if (!Utils::Fs::isValidName(newName))
+                    {
+                        emit renameFailed(tr("The name is invalid: \"%1\"").arg(newName));
+                        return false;
+                    }
+
                     try
                     {
                         const Path parentPath = getItemPath(index.parent());

src/webui/api/torrentscontroller.cpp

@@ -34,6 +34,7 @@
 #include <functional>
 
 #include <QBitArray>
+#include <QFileInfo>
 #include <QFuture>
 #include <QJsonArray>
 #include <QJsonObject>
@@ -1990,6 +1991,10 @@ void TorrentsController::renameFileAction()
 {
     requireParams({u"hash"_s, u"oldPath"_s, u"newPath"_s});
 
+    const QString newFileName = QFileInfo(params()[u"newPath"_s]).fileName();
+    if (!Utils::Fs::isValidName(newFileName))
+        throw APIError(APIErrorType::Conflict, tr("File name has invalid characters"));
+
     const auto id = BitTorrent::TorrentID::fromString(params()[u"hash"_s]);
     BitTorrent::Torrent *const torrent = BitTorrent::Session::instance()->getTorrent(id);
     if (!torrent)
@@ -2014,6 +2019,10 @@ void TorrentsController::renameFolderAction()
 {
     requireParams({u"hash"_s, u"oldPath"_s, u"newPath"_s});
 
+    const QString newFolderName = QFileInfo(params()[u"newPath"_s]).fileName();
+    if (!Utils::Fs::isValidName(newFolderName))
+        throw APIError(APIErrorType::Conflict, tr("Folder name has invalid characters"));
+
     const auto id = BitTorrent::TorrentID::fromString(params()[u"hash"_s]);
     BitTorrent::Torrent *const torrent = BitTorrent::Session::instance()->getTorrent(id);
     if (!torrent)