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// SPDX-FileCopyrightText: 2019 Alexey Andreyev <aa13q@ya.ru>
// SPDX-FileCopyrightText: 2019 Kitsune Ral <Kitsune-Ral@users.sf.net>
// SPDX-License-Identifier: LGPL-2.1-or-later
#ifdef Quotient_E2EE_ENABLED
#include "encryptionmanager.h"
#include "connection.h"
#include "crypto/e2ee.h"
#include "events/encryptedfile.h"
#include "database.h"
#include "csapi/keys.h"
#include <QtCore/QHash>
#include <QtCore/QStringBuilder>
#include <QtCore/QCryptographicHash>
#include "crypto/qolmaccount.h"
#include "crypto/qolmsession.h"
#include "crypto/qolmmessage.h"
#include "crypto/qolmerrors.h"
#include "crypto/qolmutils.h"
#include <functional>
#include <memory>
#include <openssl/evp.h>
using namespace Quotient;
using std::move;
class EncryptionManager::Private {
public:
explicit Private()
{
}
~Private() = default;
EncryptionManager* q;
// A map from SenderKey to vector of InboundSession
UnorderedMap<QString, std::vector<QOlmSessionPtr>> sessions;
void loadSessions() {
sessions = Database::instance().loadOlmSessions(static_cast<Connection *>(q->parent())->userId(), static_cast<Connection *>(q->parent())->picklingMode());
}
void saveSession(QOlmSessionPtr& session, const QString &senderKey) {
auto pickleResult = session->pickle(static_cast<Connection *>(q->parent())->picklingMode());
if (std::holds_alternative<QOlmError>(pickleResult)) {
qCWarning(E2EE) << "Failed to pickle olm session. Error" << std::get<QOlmError>(pickleResult);
return;
}
Database::instance().saveOlmSession(static_cast<Connection *>(q->parent())->userId(), senderKey, session->sessionId(), std::get<QByteArray>(pickleResult));
}
QString sessionDecryptPrekey(const QOlmMessage& message, const QString &senderKey, std::unique_ptr<QOlmAccount>& olmAccount)
{
Q_ASSERT(message.type() == QOlmMessage::PreKey);
for(auto& session : sessions[senderKey]) {
const auto matches = session->matchesInboundSessionFrom(senderKey, message);
if(std::holds_alternative<bool>(matches) && std::get<bool>(matches)) {
qCDebug(E2EE) << "Found inbound session";
const auto result = session->decrypt(message);
if(std::holds_alternative<QString>(result)) {
return std::get<QString>(result);
} else {
qCDebug(E2EE) << "Failed to decrypt prekey message";
return {};
}
}
}
qCDebug(E2EE) << "Creating new inbound session";
auto newSessionResult = olmAccount->createInboundSessionFrom(senderKey.toUtf8(), message);
if(std::holds_alternative<QOlmError>(newSessionResult)) {
qCWarning(E2EE) << "Failed to create inbound session for" << senderKey << std::get<QOlmError>(newSessionResult);
return {};
}
auto newSession = std::move(std::get<QOlmSessionPtr>(newSessionResult));
auto error = olmAccount->removeOneTimeKeys(newSession);
if (error) {
qWarning(E2EE) << "Failed to remove one time key for session" << newSession->sessionId();
}
const auto result = newSession->decrypt(message);
saveSession(newSession, senderKey);
sessions[senderKey].push_back(std::move(newSession));
if(std::holds_alternative<QString>(result)) {
return std::get<QString>(result);
} else {
qCDebug(E2EE) << "Failed to decrypt prekey message with new session";
return {};
}
}
QString sessionDecryptGeneral(const QOlmMessage& message, const QString &senderKey)
{
Q_ASSERT(message.type() == QOlmMessage::General);
for(auto& session : sessions[senderKey]) {
const auto result = session->decrypt(message);
if(std::holds_alternative<QString>(result)) {
return std::get<QString>(result);
}
}
qCWarning(E2EE) << "Failed to decrypt message";
return {};
}
};
EncryptionManager::EncryptionManager(QObject* parent)
: QObject(parent)
, d(std::make_unique<Private>())
{
d->q = this;
d->loadSessions();
}
EncryptionManager::~EncryptionManager() = default;
QString EncryptionManager::sessionDecryptMessage(
const QJsonObject& personalCipherObject, const QByteArray& senderKey, std::unique_ptr<QOlmAccount>& account)
{
QString decrypted;
int type = personalCipherObject.value(TypeKeyL).toInt(-1);
QByteArray body = personalCipherObject.value(BodyKeyL).toString().toLatin1();
if (type == 0) {
QOlmMessage preKeyMessage(body, QOlmMessage::PreKey);
decrypted = d->sessionDecryptPrekey(preKeyMessage, senderKey, account);
} else if (type == 1) {
QOlmMessage message(body, QOlmMessage::General);
decrypted = d->sessionDecryptGeneral(message, senderKey);
}
return decrypted;
}
QByteArray EncryptionManager::decryptFile(const QByteArray &ciphertext, EncryptedFile* file)
{
const auto key = QByteArray::fromBase64(file->key.k.replace(QLatin1Char('_'), QLatin1Char('/')).replace(QLatin1Char('-'), QLatin1Char('+')).toLatin1());
const auto iv = QByteArray::fromBase64(file->iv.toLatin1());
const auto sha256 = QByteArray::fromBase64(file->hashes["sha256"].toLatin1());
if(sha256 != QCryptographicHash::hash(ciphertext, QCryptographicHash::Sha256)) {
qCWarning(E2EE) << "Hash verification failed for file";
return QByteArray();
}
QByteArray plaintext(ciphertext.size(), 0);
EVP_CIPHER_CTX *ctx;
int length;
ctx = EVP_CIPHER_CTX_new();
EVP_DecryptInit_ex(ctx, EVP_aes_256_ctr(), NULL, (const unsigned char *)key.data(), (const unsigned char *)iv.data());
EVP_DecryptUpdate(ctx, (unsigned char *)plaintext.data(), &length, (const unsigned char *)ciphertext.data(), ciphertext.size());
EVP_DecryptFinal_ex(ctx, (unsigned char *)plaintext.data() + length, &length);
EVP_CIPHER_CTX_free(ctx);
return plaintext;
}
#endif // Quotient_E2EE_ENABLED
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