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// Copyright (C) 2021 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
// Qt-Security score:critical reason:cryptography
#include <QtNetwork/private/qssl_p.h>
#include "qtlsbackend_schannel_p.h"
#include "qtlskey_schannel_p.h"
#include "../shared/qwincrypt_p.h"
#include <QtNetwork/private/qtlsbackend_p.h>
#include <QtNetwork/private/qsslkey_p.h>
#include <QtNetwork/qsslkey.h>
#include <QtCore/qscopeguard.h>
#include <QtCore/qbytearray.h>
#include <QtCore/qvarlengtharray.h>
QT_BEGIN_NAMESPACE
namespace {
const wchar_t *getName(QSslKeyPrivate::Cipher cipher)
{
switch (cipher) {
case QTlsPrivate::Cipher::DesCbc:
return BCRYPT_DES_ALGORITHM;
case QTlsPrivate::Cipher::DesEde3Cbc:
return BCRYPT_3DES_ALGORITHM;
case QTlsPrivate::Cipher::Rc2Cbc:
return BCRYPT_RC2_ALGORITHM;
case QTlsPrivate::Cipher::Aes128Cbc:
case QTlsPrivate::Cipher::Aes192Cbc:
case QTlsPrivate::Cipher::Aes256Cbc:
return BCRYPT_AES_ALGORITHM;
}
Q_UNREACHABLE();
}
BCRYPT_ALG_HANDLE getHandle(QSslKeyPrivate::Cipher cipher)
{
BCRYPT_ALG_HANDLE handle;
NTSTATUS status = BCryptOpenAlgorithmProvider(
&handle, // phAlgorithm
getName(cipher), // pszAlgId
nullptr, // pszImplementation
0 // dwFlags
);
if (status < 0) {
qCWarning(lcTlsBackendSchannel, "Failed to open algorithm handle (%ld)!", status);
return nullptr;
}
return handle;
}
BCRYPT_KEY_HANDLE generateSymmetricKey(BCRYPT_ALG_HANDLE handle,
const QByteArray &key)
{
BCRYPT_KEY_HANDLE keyHandle;
NTSTATUS status = BCryptGenerateSymmetricKey(
handle, // hAlgorithm
&keyHandle, // phKey
nullptr, // pbKeyObject (can ignore)
0, // cbKeyObject (also ignoring)
reinterpret_cast<unsigned char *>(const_cast<char *>(key.data())), // pbSecret
ULONG(key.length()), // cbSecret
0 // dwFlags
);
if (status < 0) {
qCWarning(lcTlsBackendSchannel, "Failed to generate symmetric key (%ld)!", status);
return nullptr;
}
status = BCryptSetProperty(
keyHandle, // hObject
BCRYPT_CHAINING_MODE, // pszProperty
reinterpret_cast<UCHAR *>(const_cast<wchar_t *>(BCRYPT_CHAIN_MODE_CBC)), // pbInput
ARRAYSIZE(BCRYPT_CHAIN_MODE_CBC), // cbInput
0 // dwFlags
);
if (status < 0) {
BCryptDestroyKey(keyHandle);
qCWarning(lcTlsBackendSchannel, "Failed to change the symmetric key's chaining mode (%ld)!",
status);
return nullptr;
}
return keyHandle;
}
QByteArray doCrypt(QSslKeyPrivate::Cipher cipher, const QByteArray &data, const QByteArray &key,
const QByteArray &iv, bool encrypt)
{
BCRYPT_ALG_HANDLE handle = getHandle(cipher);
if (!handle)
return {};
auto handleDealloc = qScopeGuard([&handle]() {
BCryptCloseAlgorithmProvider(handle, 0);
});
BCRYPT_KEY_HANDLE keyHandle = generateSymmetricKey(handle, key);
if (!keyHandle)
return {};
auto keyHandleDealloc = qScopeGuard([&keyHandle]() {
BCryptDestroyKey(keyHandle);
});
QByteArray ivCopy = iv; // This gets modified, so we take a copy
ULONG sizeNeeded = 0;
QVarLengthArray<unsigned char> output;
auto cryptFunction = encrypt ? BCryptEncrypt : BCryptDecrypt;
for (int i = 0; i < 2; i++) {
output.resize(int(sizeNeeded));
auto input = reinterpret_cast<unsigned char *>(const_cast<char *>(data.data()));
// Need to call it twice because the first iteration lets us know the size needed.
NTSTATUS status = cryptFunction(
keyHandle, // hKey
input, // pbInput
ULONG(data.length()), // cbInput
nullptr, // pPaddingInfo
reinterpret_cast<unsigned char *>(ivCopy.data()), // pbIV
ULONG(ivCopy.length()), // cbIV
sizeNeeded ? output.data() : nullptr, // pbOutput
ULONG(output.length()), // cbOutput
&sizeNeeded, // pcbResult
BCRYPT_BLOCK_PADDING // dwFlags
);
if (status < 0) {
qCWarning(lcTlsBackendSchannel, "%s failed (%ld)!", encrypt ? "Encrypt" : "Decrypt",
status);
return {};
}
}
return QByteArray(reinterpret_cast<const char *>(output.constData()), int(sizeNeeded));
}
} // anonymous namespace
namespace QTlsPrivate {
QByteArray TlsKeySchannel::decrypt(Cipher cipher, const QByteArray &data, const QByteArray &key,
const QByteArray &iv) const
{
return doCrypt(cipher, data, key, iv, false);
}
QByteArray TlsKeySchannel::encrypt(Cipher cipher, const QByteArray &data, const QByteArray &key,
const QByteArray &iv) const
{
return doCrypt(cipher, data, key, iv, true);
}
} // namespace QTlsPrivate
QT_END_NAMESPACE