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/*
* Copyright (C) 2017 KeePassXC Team <team@keepassxc.org>
* Copyright (C) 2010 Felix Geyer <debfx@fobos.de>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 or (at your option)
* version 3 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "Kdbx3Writer.h"
#include <QBuffer>
#include "core/Database.h"
#include "crypto/CryptoHash.h"
#include "crypto/Random.h"
#include "format/KdbxXmlWriter.h"
#include "format/KeePass2.h"
#include "format/KeePass2RandomStream.h"
#include "streams/HashedBlockStream.h"
#include "streams/QtIOCompressor"
#include "streams/SymmetricCipherStream.h"
bool Kdbx3Writer::writeDatabase(QIODevice* device, Database* db)
{
m_error = false;
m_errorStr.clear();
QByteArray masterSeed = randomGen()->randomArray(32);
QByteArray encryptionIV = randomGen()->randomArray(16);
QByteArray protectedStreamKey = randomGen()->randomArray(32);
QByteArray startBytes = randomGen()->randomArray(32);
QByteArray endOfHeader = "\r\n\r\n";
if (!db->challengeMasterSeed(masterSeed)) {
raiseError(tr("Unable to issue challenge-response."));
return false;
}
if (!db->setKey(db->key(), false, true)) {
raiseError(tr("Unable to calculate master key"));
return false;
}
// generate transformed master key
CryptoHash hash(CryptoHash::Sha256);
hash.addData(masterSeed);
hash.addData(db->challengeResponseKey());
Q_ASSERT(!db->transformedMasterKey().isEmpty());
hash.addData(db->transformedMasterKey());
QByteArray finalKey = hash.result();
// write header
QBuffer header;
header.open(QIODevice::WriteOnly);
writeMagicNumbers(&header, KeePass2::SIGNATURE_1, KeePass2::SIGNATURE_2, formatVersion());
CHECK_RETURN_FALSE(writeHeaderField<quint16>(&header, KeePass2::HeaderFieldID::CipherID, db->cipher().toRfc4122()));
CHECK_RETURN_FALSE(
writeHeaderField<quint16>(&header,
KeePass2::HeaderFieldID::CompressionFlags,
Endian::sizedIntToBytes<qint32>(db->compressionAlgorithm(), KeePass2::BYTEORDER)));
auto kdf = db->kdf();
CHECK_RETURN_FALSE(writeHeaderField<quint16>(&header, KeePass2::HeaderFieldID::MasterSeed, masterSeed));
CHECK_RETURN_FALSE(writeHeaderField<quint16>(&header, KeePass2::HeaderFieldID::TransformSeed, kdf->seed()));
CHECK_RETURN_FALSE(writeHeaderField<quint16>(&header,
KeePass2::HeaderFieldID::TransformRounds,
Endian::sizedIntToBytes<qint64>(kdf->rounds(), KeePass2::BYTEORDER)));
CHECK_RETURN_FALSE(writeHeaderField<quint16>(&header, KeePass2::HeaderFieldID::EncryptionIV, encryptionIV));
CHECK_RETURN_FALSE(
writeHeaderField<quint16>(&header, KeePass2::HeaderFieldID::ProtectedStreamKey, protectedStreamKey));
CHECK_RETURN_FALSE(writeHeaderField<quint16>(&header, KeePass2::HeaderFieldID::StreamStartBytes, startBytes));
CHECK_RETURN_FALSE(writeHeaderField<quint16>(
&header,
KeePass2::HeaderFieldID::InnerRandomStreamID,
Endian::sizedIntToBytes<qint32>(static_cast<qint32>(KeePass2::ProtectedStreamAlgo::Salsa20),
KeePass2::BYTEORDER)));
CHECK_RETURN_FALSE(writeHeaderField<quint16>(&header, KeePass2::HeaderFieldID::EndOfHeader, endOfHeader));
header.close();
// write header data
CHECK_RETURN_FALSE(writeData(device, header.data()));
// hash header
const QByteArray headerHash = CryptoHash::hash(header.data(), CryptoHash::Sha256);
// write cipher stream
SymmetricCipher::Algorithm algo = SymmetricCipher::cipherToAlgorithm(db->cipher());
SymmetricCipherStream cipherStream(device, algo, SymmetricCipher::algorithmMode(algo), SymmetricCipher::Encrypt);
cipherStream.init(finalKey, encryptionIV);
if (!cipherStream.open(QIODevice::WriteOnly)) {
raiseError(cipherStream.errorString());
return false;
}
CHECK_RETURN_FALSE(writeData(&cipherStream, startBytes));
HashedBlockStream hashedStream(&cipherStream);
if (!hashedStream.open(QIODevice::WriteOnly)) {
raiseError(hashedStream.errorString());
return false;
}
QIODevice* outputDevice = nullptr;
QScopedPointer<QtIOCompressor> ioCompressor;
if (db->compressionAlgorithm() == Database::CompressionNone) {
outputDevice = &hashedStream;
} else {
ioCompressor.reset(new QtIOCompressor(&hashedStream));
ioCompressor->setStreamFormat(QtIOCompressor::GzipFormat);
if (!ioCompressor->open(QIODevice::WriteOnly)) {
raiseError(ioCompressor->errorString());
return false;
}
outputDevice = ioCompressor.data();
}
Q_ASSERT(outputDevice);
KeePass2RandomStream randomStream(KeePass2::ProtectedStreamAlgo::Salsa20);
if (!randomStream.init(protectedStreamKey)) {
raiseError(randomStream.errorString());
return false;
}
KdbxXmlWriter xmlWriter(formatVersion());
xmlWriter.writeDatabase(outputDevice, db, &randomStream, headerHash);
// Explicitly close/reset streams so they are flushed and we can detect
// errors. QIODevice::close() resets errorString() etc.
if (ioCompressor) {
ioCompressor->close();
}
if (!hashedStream.reset()) {
raiseError(hashedStream.errorString());
return false;
}
if (!cipherStream.reset()) {
raiseError(cipherStream.errorString());
return false;
}
if (xmlWriter.hasError()) {
raiseError(xmlWriter.errorString());
return false;
}
return true;
}
quint32 Kdbx3Writer::formatVersion()
{
return KeePass2::FILE_VERSION_3_1;
}
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