QSettings: Add parsing errors for '\' and '/'

When sections contains '\' or '/' we should return a parse error as the
documentation states we should not use them in sections.

Fixes: QTBUG-138648
Change-Id: I273f22104f7e7e7d33ad45b1218d7816d38ff0c5
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/io/qsettings.cpp

@@ -1425,6 +1425,13 @@ void QConfFileSettingsPrivate::syncConfFile(QConfFile *confFile)
                 }
             }
 
+            for (const auto &section : confFile->unparsedIniSections.keys()) {
+                if (section.count(u'/') > 1) {
+                    setStatus(QSettings::FormatError);
+                    break;
+                }
+            }
+
             if (!ok)
                 setStatus(QSettings::FormatError);
         }

tests/auto/corelib/io/qsettings/CMakeLists.txt

@@ -22,6 +22,7 @@ set(qsettings_resource_files
     "float.ini"
     "qt5settings.ini"
     "utf8settings.ini"
+    "incorrectsection.ini"
 )
 
 qt_internal_add_test(tst_qsettings

tests/auto/corelib/io/qsettings/incorrectsection.ini

@@ -0,0 +1,12 @@
+[MAIN]
+TestInMain=MyTestString
+Test2InMain=MyTestString2
+
+[Cars]
+Type=Renault
+Kmh=250
+
+[Cars/German]
+Type=VW
+Kmh=180
+

tests/auto/corelib/io/qsettings/tst_qsettings.cpp

@@ -208,6 +208,8 @@ private slots:
     void testReadKeys_data();
     void testReadKeys();
 
+    void testIncorrectSection();
+
 private:
     void cleanupTestFiles();
 
@@ -3735,5 +3737,13 @@ void tst_QSettings::testReadKeys()
     QCOMPARE(readValues, expectedValues);
 }
 
+void tst_QSettings::testIncorrectSection()
+{
+    QVERIFY(QFile::exists(":/incorrectsection.ini"));
+    QSettings s(":/incorrectsection.ini", QSettings::IniFormat);
+
+    QCOMPARE(s.status(), QSettings::FormatError);
+}
+
 QTEST_MAIN(tst_QSettings)
 #include "tst_qsettings.moc"