Fixed object validation in a boundary case

When a latin1 string stored that has only 2 characters or less, the size of the
data is 2+2 (2 bytes for the string length and 2 bytes for the content), so it
is quite possible that the table is located right after the data.

It should be safe to check offset+sizeof(uit) > tableOffset even for shorter
strings because values and table is always aligned, hence even for an empty
string, it will take 4 bytes.

Change-Id: I859ae0be46ebab38feeaa6aa22fbc31f2f95d443
Sanity-Review: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Lars Knoll <lars.knoll@nokia.com>

3 files changed, 32 insertions, 3 deletions

diff --git a/src/qjson.cpp b/src/qjson.cpp
index 5936949..41d0144 100644
--- a/src/qjson.cpp
+++ b/src/qjson.cpp
@@ -270,7 +270,7 @@ bool Value::isValid(const Base *b) const
 
     if (!offset)
         return true;
-    if (offset + sizeof(uint) >= b->tableOffset)
+    if (offset + sizeof(uint) > b->tableOffset)
         return false;
 
     int s = usedStorage(b);
diff --git a/tests/auto/test2.json b/tests/auto/test2.json
new file mode 100644
index 0000000..303f879
--- /dev/null
+++ b/tests/auto/test2.json
@@ -0,0 +1 @@
+{ "foo": ["ab"] }
diff --git a/tests/auto/tst_qtjson.cpp b/tests/auto/tst_qtjson.cpp
index 70dfa74..4a749ec 100644
--- a/tests/auto/tst_qtjson.cpp
+++ b/tests/auto/tst_qtjson.cpp
@@ -89,6 +89,8 @@ private Q_SLOTS:
     void toJson();
     void fromJson();
     void fromBinary();
+    void toAndFromBinary_data();
+    void toAndFromBinary();
     void parseNumbers();
     void parseStrings();
     void testParser();
@@ -469,7 +471,9 @@ void TestQtJson::testObjectNestedEmpty()
     QJsonDocument(object).toBinaryData();
     QVERIFY(object.value("inner").toObject().isEmpty());
     QVERIFY(object.value("inner2").toObject().isEmpty());
-    QJsonObject reconstituted(QJsonDocument::fromBinaryData(QJsonDocument(object).toBinaryData()).object());
+    QJsonDocument doc = QJsonDocument::fromBinaryData(QJsonDocument(object).toBinaryData());
+    QVERIFY(doc.isValid());
+    QJsonObject reconstituted(doc.object());
     QCOMPARE(reconstituted.value("inner").toObject().size(), 0);
     QCOMPARE(reconstituted.value("inner").type(), QJsonValue::Object);
     QCOMPARE(reconstituted.value("inner2").type(), QJsonValue::Object);
@@ -1013,17 +1017,41 @@ void TestQtJson::fromBinary()
     QByteArray testJson = file.readAll();
 
     QJsonDocument doc = QJsonDocument::fromJson(testJson);
+    QJsonDocument outdoc = QJsonDocument::fromBinaryData(doc.toBinaryData());
+    QVERIFY(outdoc.isValid());
+    QVERIFY(doc == outdoc);
 
     QFile bfile(QLatin1String("test.bjson"));
     bfile.open(QFile::ReadOnly);
     QByteArray binary = bfile.readAll();
 
     QJsonDocument bdoc = QJsonDocument::fromBinaryData(binary);
-
+    QVERIFY(bdoc.isValid());
     QVERIFY(doc.toVariant() == bdoc.toVariant());
     QVERIFY(doc == bdoc);
 }
 
+void TestQtJson::toAndFromBinary_data()
+{
+    QTest::addColumn<QString>("filename");
+    QTest::newRow("test.json") << QString::fromLatin1("test.json");
+    QTest::newRow("test2.json") << QString::fromLatin1("test2.json");
+}
+
+void TestQtJson::toAndFromBinary()
+{
+    QFETCH(QString, filename);
+    QFile file(filename);
+    QVERIFY(file.open(QFile::ReadOnly));
+    QByteArray data = file.readAll();
+
+    QJsonDocument doc = QJsonDocument::fromJson(data);
+    QVERIFY(doc.isValid());
+    QJsonDocument outdoc = QJsonDocument::fromBinaryData(doc.toBinaryData());
+    QVERIFY(outdoc.isValid());
+    QVERIFY(doc == outdoc);
+}
+
 void TestQtJson::parseNumbers()
 {
     {