Implement reading encrypted kdbx files.

src/format/KeePass2Reader.cpp

@@ -0,0 +1,273 @@
+/*
+ *  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 "KeePass2Reader.h"
+
+#include <QtCore/QBuffer>
+#include <QtCore/QFile>
+#include <QtCore/QIODevice>
+
+#include "KeePass2.h"
+#include "KeePass2XmlReader.h"
+#include "crypto/CryptoHash.h"
+#include "streams/HashedBlockStream.h"
+#include "streams/SymmetricCipherStream.h"
+
+const QSysInfo::Endian KeePass2Reader::BYTEORDER = QSysInfo::LittleEndian;
+
+Database* KeePass2Reader::readDatabase(QIODevice* device, const CompositeKey& key)
+{
+    m_device = device;
+    m_error = false;
+    m_errorStr = QString();
+    m_headerEnd = false;
+    m_cipher = Uuid();
+
+    bool ok;
+
+    quint32 signature1 = Endian::readUInt32(m_device, BYTEORDER, &ok);
+    if (!ok || signature1 != KeePass2::SIGNATURE_1) {
+        raiseError("1");
+        return 0;
+    }
+
+    quint32 signature2 = Endian::readUInt32(m_device, BYTEORDER, &ok);
+    if (!ok || signature2 != KeePass2::SIGNATURE_2) {
+        raiseError("2");
+        return 0;
+    }
+
+    quint32 version = Endian::readUInt32(m_device, BYTEORDER, &ok) & KeePass2::FILE_VERSION_CRITICAL_MASK;
+    quint32 expectedVersion = KeePass2::FILE_VERSION & KeePass2::FILE_VERSION_CRITICAL_MASK;
+    // TODO do we support old Kdbx versions?
+    if (!ok || (version != expectedVersion)) {
+        raiseError("3");
+        return 0;
+    }
+
+    while (readHeaderField() && !error()) {
+    }
+
+    CryptoHash hash(CryptoHash::Sha256);
+    hash.addData(m_masterSeed);
+    hash.addData(key.transform(m_transformSeed, m_transformRounds));
+    QByteArray finalKey = hash.result();
+
+    SymmetricCipherStream cipherStream(device, SymmetricCipher::Aes256, SymmetricCipher::Cbc, SymmetricCipher::Decrypt, finalKey, m_encryptionIV);
+    cipherStream.open(QIODevice::ReadOnly);
+
+    QByteArray realStart = cipherStream.read(32);
+
+    if (realStart != m_streamStartBytes) {
+        raiseError("4");
+    }
+
+    HashedBlockStream hashedStream(&cipherStream);
+    hashedStream.open(QIODevice::ReadOnly);
+
+    KeePass2XmlReader xmlReader;
+    Database* db = xmlReader.readDatabase(&hashedStream);
+    return db;
+}
+
+Database* KeePass2Reader::readDatabase(const QString& filename, const CompositeKey& key)
+{
+    QFile file(filename);
+    file.open(QFile::ReadOnly);
+    Database* db = readDatabase(&file, key);
+    // TODO check for QFile errors
+    return db;
+}
+
+bool KeePass2Reader::error()
+{
+    return m_error;
+}
+
+QString KeePass2Reader::errorString()
+{
+    // TODO
+    return QString();
+}
+
+void KeePass2Reader::raiseError(const QString& str)
+{
+    // TODO
+    qWarning("KeePass2Reader error: %s", qPrintable(str));
+    m_error = true;
+}
+
+bool KeePass2Reader::readHeaderField()
+{
+    QByteArray fieldIDArray = m_device->read(1);
+    if (fieldIDArray.size() != 1) {
+        raiseError("");
+        return false;
+    }
+    quint8 fieldID = fieldIDArray.at(0);
+
+    bool ok;
+    quint16 fieldLen = Endian::readUInt16(m_device, BYTEORDER, &ok);
+    if (!ok) {
+        raiseError("");
+        return false;
+    }
+
+    QByteArray fieldData;
+    if (fieldLen != 0) {
+        fieldData = m_device->read(fieldLen);
+        if (fieldData.size() != fieldLen) {
+            raiseError("");
+            return false;
+        }
+    }
+
+    switch (fieldID) {
+    case KeePass2::EndOfHeader:
+        m_headerEnd = true;
+        break;
+
+    case KeePass2::CipherID:
+        setCipher(fieldData);
+        break;
+
+    case KeePass2::CompressionFlags:
+        setCompressionFlags(fieldData);
+        break;
+
+    case KeePass2::MasterSeed:
+        setMasterSeed(fieldData);
+        break;
+
+    case KeePass2::TransformSeed:
+        setTransformSeed(fieldData);
+        break;
+
+    case KeePass2::TransformRounds:
+        setTansformRounds(fieldData);
+        break;
+
+    case KeePass2::EncryptionIV:
+        setEncryptionIV(fieldData);
+        break;
+
+    case KeePass2::ProtectedStreamKey:
+        setProtectedStreamKey(fieldData);
+        break;
+
+    case KeePass2::StreamStartBytes:
+        setStreamStartBytes(fieldData);
+        break;
+
+    case KeePass2::InnerRandomStreamID:
+        setInnerRandomStreamID(fieldData);
+        break;
+
+    default:
+        qWarning("Unknown header field read: id=%d", fieldID);
+        break;
+    }
+
+    return !m_headerEnd;
+}
+
+void KeePass2Reader::setCipher(const QByteArray& data)
+{
+    if (data.size() != Uuid::LENGTH) {
+        raiseError("");
+    }
+    else {
+        m_cipher = Uuid(data);
+    }
+}
+
+void KeePass2Reader::setCompressionFlags(const QByteArray& data)
+{
+    if (data.size() != 4) {
+        raiseError("");
+    }
+    else {
+        quint32 id = Endian::bytesToUInt32(data, BYTEORDER);
+
+        if (id >= KeePass2::CompressionCount) {
+            raiseError("");
+        }
+        else {
+            m_compression = id;
+        }
+    }
+}
+
+void KeePass2Reader::setMasterSeed(const QByteArray& data)
+{
+    if (data.size() != 32) {
+        raiseError("");
+    }
+    else {
+        m_masterSeed = data;
+    }
+}
+
+void KeePass2Reader::setTransformSeed(const QByteArray& data)
+{
+    if (data.size() != 32) {
+        raiseError("");
+    }
+    else {
+        m_transformSeed = data;
+    }
+}
+
+void KeePass2Reader::setTansformRounds(const QByteArray& data)
+{
+    if (data.size() != 8) {
+        raiseError("");
+    }
+    else {
+        m_transformRounds = Endian::bytesToUInt64(data, BYTEORDER);
+    }
+}
+
+void KeePass2Reader::setEncryptionIV(const QByteArray& data)
+{
+    if (data.size() != 16) {
+        raiseError("");
+    }
+    else {
+        m_encryptionIV = data;
+    }
+}
+
+void KeePass2Reader::setProtectedStreamKey(const QByteArray& data)
+{
+    // TODO ignore?
+}
+
+void KeePass2Reader::setStreamStartBytes(const QByteArray& data)
+{
+    if (data.size() != 32) {
+        raiseError("");
+    }
+    else {
+        m_streamStartBytes = data;
+    }
+}
+
+void KeePass2Reader::setInnerRandomStreamID(const QByteArray& data)
+{
+    // TODO ignore?
+}