Sanitize username to prevent single-instance detection failure (#12559)

---------

Co-authored-by: Jonathan White <support@dmapps.us>

src/core/Tools.cpp

@@ -426,6 +426,29 @@ namespace Tools
         return filename.trimmed();
     }
 
+    QString cleanUsername()
+    {
+#if defined(Q_OS_WIN)
+        QString userName = qgetenv("USERNAME");
+        if (userName.isEmpty()) {
+            userName = qgetenv("USER");
+        }
+#else
+        QString userName = qgetenv("USER");
+        if (userName.isEmpty()) {
+            userName = qgetenv("USERNAME");
+        }
+#endif
+        // Sanitize username for file safety
+        userName = userName.trimmed();
+        // Replace <>:"/\|?* with _
+        userName.replace(QRegularExpression(R"([<>:\"\/\\|?*])"), "_");
+        // Remove trailing dots and spaces
+        userName.replace(QRegularExpression(R"([.\s]+$)"), "");
+
+        return userName;
+    }
+
     QVariantMap qo2qvm(const QObject* object, const QStringList& ignoredProperties)
     {
         QVariantMap result;

src/core/Tools.h

@@ -48,6 +48,7 @@ namespace Tools
     QString envSubstitute(const QString& filepath,
                           QProcessEnvironment environment = QProcessEnvironment::systemEnvironment());
     QString cleanFilename(QString filename);
+    QString cleanUsername();
 
     template <class T> QSet<T> asSet(const QList<T>& a)
     {

src/gui/Application.cpp

@@ -20,6 +20,7 @@
 #include "Application.h"
 
 #include "core/Bootstrap.h"
+#include "core/Tools.h"
 #include "gui/MainWindow.h"
 #include "gui/MessageBox.h"
 #include "gui/osutils/OSUtils.h"
@@ -31,6 +32,7 @@
 #include <QLocalSocket>
 #include <QLockFile>
 #include <QPixmapCache>
+#include <QRegularExpression>
 #include <QSocketNotifier>
 #include <QStandardPaths>
 
@@ -63,20 +65,19 @@ Application::Application(int& argc, char** argv)
     registerUnixSignals();
 #endif
 
-    QString userName = qgetenv("USER");
-    if (userName.isEmpty()) {
-        userName = qgetenv("USERNAME");
-    }
-    QString identifier = "keepassxc";
-    if (!userName.isEmpty()) {
-        identifier += "-" + userName;
+    // Build identifier
+    auto identifier = QStringLiteral("keepassxc");
+    auto username = Tools::cleanUsername();
+    if (!username.isEmpty()) {
+        identifier += QChar('-') + username;
     }
 #ifdef QT_DEBUG
-    // In DEBUG mode don't interfere with Release instances
-    identifier += "-DEBUG";
+    // In DEBUG mode don’t interfere with Release instances
+    identifier += QStringLiteral("-DEBUG");
 #endif
-    QString lockName = identifier + ".lock";
-    m_socketName = identifier + ".socket";
+
+    QString lockName = identifier + QStringLiteral(".lock");
+    m_socketName = identifier + QStringLiteral(".socket");
 
     // According to documentation we should use RuntimeLocation on *nixes, but even Qt doesn't respect
     // this and creates sockets in TempLocation, so let's be consistent.

tests/TestTools.cpp

@@ -428,3 +428,26 @@ void TestTools::testIsTextMimeType()
         QVERIFY(!Tools::isTextMimeType(noText));
     }
 }
+
+// Test sanitization logic for Tools::cleanUsername
+void TestTools::testCleanUsername()
+{
+    // Test vars
+    QFETCH(QString, input);
+    QFETCH(QString, expected);
+
+    qputenv("USER", input.toUtf8());
+    qputenv("USERNAME", input.toUtf8());
+    QCOMPARE(Tools::cleanUsername(), expected);
+}
+
+void TestTools::testCleanUsername_data()
+{
+    QTest::addColumn<QString>("input");
+    QTest::addColumn<QString>("expected");
+
+    QTest::newRow("Leading and trailing spaces") << "  user  " << "user";
+    QTest::newRow("Special characters") << R"(user<>:"/\|?*name)" << "user_________name";
+    QTest::newRow("Trailing dots and spaces") << "username...   " << "username";
+    QTest::newRow("Combination of issues") << R"(  user<>:"/\|?*name...   )" << "user_________name";
+}

tests/TestTools.h

@@ -41,6 +41,8 @@ private slots:
     void testGetMimeType();
     void testGetMimeTypeByFileInfo();
     void testIsTextMimeType();
+    void testCleanUsername();
+    void testCleanUsername_data();
 };
 
 #endif // KEEPASSX_TESTTOOLS_H