CBOR support: prevent overflowing QByteArray's max allocation

QByteArray doesn't like it.

Apply the same protection to QString, which we know uses the same
backend but uses elements twice as big. That means it can contain
slightly more than half as many elements, but exact half will suffice
for our needs.

Change-Id: Iaa63461109844e978376fffd15f9d4c7a9137856
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

5 files changed, 223 insertions, 16 deletions

diff --git a/tests/auto/corelib/serialization/cborlargedatavalidation.cpp b/tests/auto/corelib/serialization/cborlargedatavalidation.cpp
new file mode 100644
index 0000000000..9abfe0f575
--- /dev/null
+++ b/tests/auto/corelib/serialization/cborlargedatavalidation.cpp
@@ -0,0 +1,134 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 Intel Corporation.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtCore module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <QtTest/QtTest>
+#include <cbor.h>
+
+namespace {
+// A QIODevice that supplies a fixed header followed by a large sequence of
+// null bytes up until a pre-determined size.
+class LargeIODevice final : public QIODevice
+{
+public:
+    qint64 realSize;
+    QByteArray start;
+
+    LargeIODevice(const QByteArray &start, qint64 size, QObject *parent = nullptr)
+        : QIODevice(parent), realSize(size), start(start)
+    {}
+
+    qint64 size() const override { return realSize; }
+    bool isSequential() const override { return false; }
+
+protected:
+    qint64 readData(char *data, qint64 maxlen) override;
+    qint64 writeData(const char *, qint64) override { return -1; }
+};
+};
+
+qint64 LargeIODevice::readData(char *data, qint64 maxlen)
+{
+    qint64 p = pos();
+    if (maxlen > realSize - p)
+        maxlen = realSize - p;
+    memset(data, '\0', maxlen);
+
+    qint64 fromstart = start.size() - p;
+    if (fromstart > maxlen)
+        fromstart = maxlen;
+    else if (fromstart < 0)
+        fromstart = 0;
+    if (fromstart)
+        memcpy(data, start.constData() + p, fromstart);
+    return maxlen;
+}
+
+void addValidationLargeData(qsizetype minInvalid, qsizetype maxInvalid)
+{
+    char toolong[2 + sizeof(qsizetype)] = { char(0x81) };
+    for (qsizetype v = maxInvalid; v >= minInvalid; --v) {
+        // 0x5a for 32-bit, 0x5b for 64-bit
+        toolong[1] = sizeof(v) > 4 ? 0x5b : 0x5a;
+        qToBigEndian(v, toolong + 2);
+
+        QTest::addRow("bytearray-too-big-for-qbytearray-%llx", v)
+                << QByteArray(toolong, sizeof(toolong)) << 0 << CborErrorDataTooLarge;
+        toolong[1] |= 0x20;
+
+        // QCborStreamReader::readString copies to a QByteArray first
+        QTest::addRow("string-too-big-for-qbytearray-%llx", v)
+                << QByteArray(toolong, sizeof(toolong)) << 0 << CborErrorDataTooLarge;
+    }
+}
+
+void addValidationHugeDevice(qsizetype byteArrayInvalid, qsizetype stringInvalid)
+{
+    qRegisterMetaType<QSharedPointer<QIODevice>>();
+    QTest::addColumn<QSharedPointer<QIODevice>>("device");
+    QTest::addColumn<CborError>("expectedError");
+
+    char buf[1 + sizeof(quint64)];
+    auto device = [&buf](QCborStreamReader::Type t, quint64 size) {
+        buf[0] = quint8(t) | 0x1b;
+        qToBigEndian(size, buf + 1);
+        size += sizeof(buf);
+        QSharedPointer<QIODevice> p =
+                QSharedPointer<LargeIODevice>::create(QByteArray(buf, sizeof(buf)), size);
+        return p;
+    };
+
+    // do the exact limits
+    QTest::newRow("bytearray-just-too-big")
+            << device(QCborStreamReader::ByteArray, byteArrayInvalid) << CborErrorDataTooLarge;
+    QTest::newRow("string-just-too-big")
+            << device(QCborStreamReader::String, stringInvalid) << CborErrorDataTooLarge;
+
+    auto addSize = [=](const char *sizename, qint64 size) {
+        if (byteArrayInvalid < size)
+            QTest::addRow("bytearray-%s", sizename)
+                << device(QCborStreamReader::ByteArray, size) << CborErrorDataTooLarge;
+        if (stringInvalid < size)
+            QTest::addRow("string-%s", sizename)
+                << device(QCborStreamReader::String, size) << CborErrorDataTooLarge;
+    };
+    addSize("1GB", quint64(1) << 30);
+    addSize("2GB", quint64(1) << 31);
+    addSize("4GB", quint64(1) << 32);
+    addSize("max", std::numeric_limits<qint64>::max() - sizeof(buf));
+}
diff --git a/tests/auto/corelib/serialization/qcborstreamreader/qcborstreamreader.pro b/tests/auto/corelib/serialization/qcborstreamreader/qcborstreamreader.pro
index 5df331314a..b758de1a9e 100644
--- a/tests/auto/corelib/serialization/qcborstreamreader/qcborstreamreader.pro
+++ b/tests/auto/corelib/serialization/qcborstreamreader/qcborstreamreader.pro
@@ -1,4 +1,4 @@
-QT = core testlib
+QT = core-private testlib
 TARGET = tst_qcborstreamreader
 CONFIG += testcase
 SOURCES += \
diff --git a/tests/auto/corelib/serialization/qcborstreamreader/tst_qcborstreamreader.cpp b/tests/auto/corelib/serialization/qcborstreamreader/tst_qcborstreamreader.cpp
index 28d29168fb..f969bb9074 100644
--- a/tests/auto/corelib/serialization/qcborstreamreader/tst_qcborstreamreader.cpp
+++ b/tests/auto/corelib/serialization/qcborstreamreader/tst_qcborstreamreader.cpp
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2018 Intel Corporation.
+** Copyright (C) 2020 Intel Corporation.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtCore module of the Qt Toolkit.
@@ -40,6 +40,8 @@
 #include <QtCore/qcborstream.h>
 #include <QtTest>
 
+#include <QtCore/private/qbytearray_p.h>
+
 class tst_QCborStreamReader : public QObject
 {
     Q_OBJECT
@@ -73,6 +75,8 @@ private Q_SLOTS:
     void next();
     void validation_data();
     void validation();
+    void hugeDeviceValidation_data();
+    void hugeDeviceValidation();
     void recursionLimit_data();
     void recursionLimit();
 
@@ -902,16 +906,26 @@ void tst_QCborStreamReader::next()
     QVERIFY(doit("\xbf\x9f\1\xff\x9f" + data + "\xff\xff"));
 }
 
+#include "../cborlargedatavalidation.cpp"
+
 void tst_QCborStreamReader::validation_data()
 {
+    // Add QCborStreamReader-specific limitations due to use of QByteArray and
+    // QString, which are allocated by QArrayData::allocate().
+    const qsizetype MaxInvalid = std::numeric_limits<QByteArray::size_type>::max();
+    const qsizetype MinInvalid = MaxByteArraySize + 1;
+
     addValidationColumns();
-    addValidationData();
+    addValidationData(MinInvalid);
+    addValidationLargeData(MinInvalid, MaxInvalid);
 }
 
 void tst_QCborStreamReader::validation()
 {
     QFETCH_GLOBAL(bool, useDevice);
     QFETCH(QByteArray, data);
+    QFETCH(CborError, expectedError);
+    QCborError error = { QCborError::Code(expectedError) };
 
     QBuffer buffer(&data);
     QCborStreamReader reader(data);
@@ -920,12 +934,39 @@ void tst_QCborStreamReader::validation()
         reader.setDevice(&buffer);
     }
     parse(reader, data);
-    QVERIFY(reader.lastError() != QCborError::NoError);
+    QCOMPARE(reader.lastError(), error);
+
+    // next() should fail
+    reader.reset();
+    QVERIFY(!reader.next());
+    QCOMPARE(reader.lastError(), error);
+}
+
+void tst_QCborStreamReader::hugeDeviceValidation_data()
+{
+    addValidationHugeDevice(MaxByteArraySize + 1, MaxStringSize + 1);
+}
+
+void tst_QCborStreamReader::hugeDeviceValidation()
+{
+    QFETCH_GLOBAL(bool, useDevice);
+    if (!useDevice)
+        return;
+
+    QFETCH(QSharedPointer<QIODevice>, device);
+    QFETCH(CborError, expectedError);
+    QCborError error = { QCborError::Code(expectedError) };
+
+    device->open(QIODevice::ReadOnly | QIODevice::Unbuffered);
+    QCborStreamReader reader(device.data());
+
+    QVERIFY(parseOne(reader).isEmpty());
+    QCOMPARE(reader.lastError(), error);
 
     // next() should fail
     reader.reset();
     QVERIFY(!reader.next());
-    QVERIFY(reader.lastError() != QCborError::NoError);
+    QCOMPARE(reader.lastError(), error);
 }
 
 static const int Recursions = 3;
diff --git a/tests/auto/corelib/serialization/qcborvalue/qcborvalue.pro b/tests/auto/corelib/serialization/qcborvalue/qcborvalue.pro
index 9dd67da1f0..4d01b290f5 100644
--- a/tests/auto/corelib/serialization/qcborvalue/qcborvalue.pro
+++ b/tests/auto/corelib/serialization/qcborvalue/qcborvalue.pro
@@ -1,4 +1,4 @@
-QT = core testlib
+QT = core-private testlib
 TARGET = tst_qcborvalue
 CONFIG += testcase
 SOURCES += \
diff --git a/tests/auto/corelib/serialization/qcborvalue/tst_qcborvalue.cpp b/tests/auto/corelib/serialization/qcborvalue/tst_qcborvalue.cpp
index 49bb9cc144..488771d059 100644
--- a/tests/auto/corelib/serialization/qcborvalue/tst_qcborvalue.cpp
+++ b/tests/auto/corelib/serialization/qcborvalue/tst_qcborvalue.cpp
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2018 Intel Corporation.
+** Copyright (C) 2020 Intel Corporation.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtCore module of the Qt Toolkit.
@@ -40,6 +40,8 @@
 #include <QtCore/qcborvalue.h>
 #include <QtTest>
 
+#include <QtCore/private/qbytearray_p.h>
+
 Q_DECLARE_METATYPE(QCborKnownTags)
 Q_DECLARE_METATYPE(QCborValue)
 Q_DECLARE_METATYPE(QCborValue::EncodingOptions)
@@ -102,6 +104,8 @@ private slots:
     void fromCborStreamReaderIODevice();
     void validation_data();
     void validation();
+    void hugeDeviceValidation_data();
+    void hugeDeviceValidation();
     void recursionLimit_data();
     void recursionLimit();
     void toDiagnosticNotation_data();
@@ -1689,10 +1693,17 @@ void tst_QCborValue::fromCborStreamReaderIODevice()
     fromCbor_common(doCheck);
 }
 
+#include "../cborlargedatavalidation.cpp"
+
 void tst_QCborValue::validation_data()
 {
+    // Add QCborStreamReader-specific limitations due to use of QByteArray and
+    // QString, which are allocated by QArrayData::allocate().
+    const qsizetype MaxInvalid = std::numeric_limits<QByteArray::size_type>::max();
+    const qsizetype MinInvalid = MaxByteArraySize + 1;
     addValidationColumns();
-    addValidationData();
+    addValidationData(MinInvalid);
+    addValidationLargeData(MinInvalid, MaxInvalid);
 
     // These tests say we have arrays and maps with very large item counts.
     // They are meant to ensure we don't pre-allocate a lot of memory
@@ -1700,28 +1711,49 @@ void tst_QCborValue::validation_data()
     // elements in the stream is only 2, so we should get an unexpected EOF
     // error. QCborValue internally uses 16 bytes per element, so we get to
     // 2 GB at 2^27 elements.
-    QTest::addRow("very-large-array-no-overflow") << raw("\x9a\x07\xff\xff\xff" "\0\0");
-    QTest::addRow("very-large-array-overflow1") << raw("\x9a\x40\0\0\0" "\0\0");
+    QTest::addRow("very-large-array-no-overflow") << raw("\x9a\x07\xff\xff\xff" "\0\0") << 0 << CborErrorUnexpectedEOF;
+    QTest::addRow("very-large-array-overflow1") << raw("\x9a\x40\0\0\0" "\0\0") << 0 << CborErrorUnexpectedEOF;
 
     // this makes sure we don't accidentally clip to 32-bit: sending 2^32+2 elements
-    QTest::addRow("very-large-array-overflow2") << raw("\x9b\0\0\0\1""\0\0\0\2" "\0\0");
+    QTest::addRow("very-large-array-overflow2") << raw("\x9b\0\0\0\1""\0\0\0\2" "\0\0") << 0 << CborErrorDataTooLarge;
 }
 
 void tst_QCborValue::validation()
 {
     QFETCH(QByteArray, data);
+    QFETCH(CborError, expectedError);
+    QCborError error = { QCborError::Code(expectedError) };
 
-    QCborParserError error;
-    QCborValue decoded = QCborValue::fromCbor(data, &error);
-    QVERIFY(error.error != QCborError{});
+    QCborParserError parserError;
+    QCborValue decoded = QCborValue::fromCbor(data, &parserError);
+    QCOMPARE(parserError.error, error);
 
     if (data.startsWith('\x81')) {
         // decode without the array prefix
-        decoded = QCborValue::fromCbor(data.mid(1), &error);
-        QVERIFY(error.error != QCborError{});
+        char *ptr = const_cast<char *>(data.constData());
+        QByteArray mid = QByteArray::fromRawData(ptr + 1, data.size() - 1);
+        decoded = QCborValue::fromCbor(mid, &parserError);
+        QCOMPARE(parserError.error, error);
     }
 }
 
+void tst_QCborValue::hugeDeviceValidation_data()
+{
+    addValidationHugeDevice(MaxByteArraySize + 1, MaxStringSize + 1);
+}
+
+void tst_QCborValue::hugeDeviceValidation()
+{
+    QFETCH(QSharedPointer<QIODevice>, device);
+    QFETCH(CborError, expectedError);
+    QCborError error = { QCborError::Code(expectedError) };
+
+    device->open(QIODevice::ReadOnly | QIODevice::Unbuffered);
+    QCborStreamReader reader(device.data());
+    QCborValue decoded = QCborValue::fromCbor(reader);
+    QCOMPARE(reader.lastError(), error);
+}
+
 void tst_QCborValue::recursionLimit_data()
 {
     constexpr int RecursionAttempts = 4096;