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// SPDX-FileCopyrightText: 2021 Alexey Andreyev <aa13q@ya.ru>
//
// SPDX-License-Identifier: LGPL-2.1-or-later
#ifdef Quotient_E2EE_ENABLED
#include "olm/session.h"
#include "olm/utils.h"
#include "logging.h"
#include <cstring>
using namespace Quotient;
OlmError lastError(OlmSession* session) {
const std::string error_raw = olm_session_last_error(session);
return fromString(error_raw);
}
Quotient::QOlmSession::~QOlmSession()
{
olm_clear_session(m_session);
delete[](reinterpret_cast<uint8_t *>(m_session));
}
OlmSession* QOlmSession::create()
{
return olm_session(new uint8_t[olm_session_size()]);
}
std::variant<std::unique_ptr<QOlmSession>, OlmError> QOlmSession::createInbound(QOlmAccount *account, const Message &preKeyMessage, bool from, const QString &theirIdentityKey)
{
if (preKeyMessage.type() != Message::PreKey) {
qCDebug(E2EE) << "The message is not a pre-key";
throw BadMessageFormat;
}
const auto olmSession = create();
QByteArray oneTimeKeyMessageBuf = preKeyMessage.toCiphertext();
QByteArray theirIdentityKeyBuf = theirIdentityKey.toUtf8();
size_t error = 0;
if (from) {
error = olm_create_inbound_session_from(olmSession, account->data(), theirIdentityKeyBuf.data(), theirIdentityKeyBuf.length(), oneTimeKeyMessageBuf.data(), oneTimeKeyMessageBuf.length());
} else {
error = olm_create_inbound_session(olmSession, account->data(), oneTimeKeyMessageBuf.data(), oneTimeKeyMessageBuf.length());
}
if (error == olm_error()) {
const auto lastErr = lastError(olmSession);
if (lastErr == OlmError::NotEnoughRandom) {
throw lastErr;
}
return lastErr;
}
return std::make_unique<QOlmSession>(olmSession);
}
std::variant<std::unique_ptr<QOlmSession>, OlmError> QOlmSession::createInboundSession(QOlmAccount *account, const Message &preKeyMessage)
{
return createInbound(account, preKeyMessage);
}
std::variant<std::unique_ptr<QOlmSession>, OlmError> QOlmSession::createInboundSessionFrom(QOlmAccount *account, const QString &theirIdentityKey, const Message &preKeyMessage)
{
return createInbound(account, preKeyMessage, true, theirIdentityKey);
}
std::variant<std::unique_ptr<QOlmSession>, OlmError> QOlmSession::createOutboundSession(QOlmAccount *account, const QString &theirIdentityKey, const QString &theirOneTimeKey)
{
auto *olmOutboundSession = create();
const auto randomLen = olm_create_outbound_session_random_length(olmOutboundSession);
QByteArray randomBuf = getRandom(randomLen);
QByteArray theirIdentityKeyBuf = theirIdentityKey.toUtf8();
QByteArray theirOneTimeKeyBuf = theirOneTimeKey.toUtf8();
const auto error = olm_create_outbound_session(olmOutboundSession,
account->data(),
reinterpret_cast<uint8_t *>(theirIdentityKeyBuf.data()), theirIdentityKeyBuf.length(),
reinterpret_cast<uint8_t *>(theirOneTimeKeyBuf.data()), theirOneTimeKeyBuf.length(),
reinterpret_cast<uint8_t *>(randomBuf.data()), randomBuf.length());
if (error == olm_error()) {
const auto lastErr = lastError(olmOutboundSession);
if (lastErr == OlmError::NotEnoughRandom) {
throw lastErr;
}
return lastErr;
}
randomBuf.clear();
return std::make_unique<QOlmSession>(olmOutboundSession);
}
std::variant<QByteArray, OlmError> QOlmSession::pickle(const PicklingMode &mode)
{
QByteArray pickledBuf(olm_pickle_session_length(m_session), '0');
QByteArray key = toKey(mode);
const auto error = olm_pickle_session(m_session, key.data(), key.length(),
pickledBuf.data(), pickledBuf.length());
if (error == olm_error()) {
return lastError(m_session);
}
key.clear();
return pickledBuf;
}
std::variant<std::unique_ptr<QOlmSession>, OlmError> QOlmSession::unpickle(const QByteArray &pickled, const PicklingMode &mode)
{
QByteArray pickledBuf = pickled;
auto *olmSession = create();
QByteArray key = toKey(mode);
const auto error = olm_unpickle_session(olmSession, key.data(), key.length(),
pickledBuf.data(), pickledBuf.length());
if (error == olm_error()) {
return lastError(olmSession);
}
key.clear();
return std::make_unique<QOlmSession>(olmSession);
}
Message QOlmSession::encrypt(const QString &plaintext)
{
QByteArray plaintextBuf = plaintext.toUtf8();
const auto messageMaxLen = olm_encrypt_message_length(m_session, plaintextBuf.length());
QByteArray messageBuf(messageMaxLen, '0');
const auto messageType = encryptMessageType();
const auto randomLen = olm_encrypt_random_length(m_session);
QByteArray randomBuf = getRandom(randomLen);
const auto error = olm_encrypt(m_session,
reinterpret_cast<uint8_t *>(plaintextBuf.data()), plaintextBuf.length(),
reinterpret_cast<uint8_t *>(randomBuf.data()), randomBuf.length(),
reinterpret_cast<uint8_t *>(messageBuf.data()), messageBuf.length());
if (error == olm_error()) {
throw lastError(m_session);
}
return Message(messageBuf, messageType);
}
std::variant<QString, OlmError> QOlmSession::decrypt(const Message &message) const
{
const auto messageType = message.type();
const auto ciphertext = message.toCiphertext();
const auto messageTypeValue = messageType == Message::Type::General
? OLM_MESSAGE_TYPE_MESSAGE : OLM_MESSAGE_TYPE_PRE_KEY;
// We need to clone the message because
// olm_decrypt_max_plaintext_length destroys the input buffer
QByteArray messageBuf(ciphertext.length(), '0');
std::copy(message.begin(), message.end(), messageBuf.begin());
const auto plaintextMaxLen = olm_decrypt_max_plaintext_length(m_session, messageTypeValue,
reinterpret_cast<uint8_t *>(messageBuf.data()), messageBuf.length());
if (plaintextMaxLen == olm_error()) {
return lastError(m_session);
}
QByteArray plaintextBuf(plaintextMaxLen, '0');
QByteArray messageBuf2(ciphertext.length(), '0');
std::copy(message.begin(), message.end(), messageBuf2.begin());
const auto plaintextResultLen = olm_decrypt(m_session, messageTypeValue,
reinterpret_cast<uint8_t *>(messageBuf2.data()), messageBuf2.length(),
reinterpret_cast<uint8_t *>(plaintextBuf.data()), plaintextMaxLen);
if (plaintextResultLen == olm_error()) {
const auto lastErr = lastError(m_session);
if (lastErr == OlmError::OutputBufferTooSmall) {
throw lastErr;
}
return lastErr;
}
QByteArray output(plaintextResultLen, '0');
std::memcpy(output.data(), plaintextBuf.data(), plaintextResultLen);
plaintextBuf.clear();
return output;
}
Message::Type QOlmSession::encryptMessageType()
{
const auto messageTypeResult = olm_encrypt_message_type(m_session);
if (messageTypeResult == olm_error()) {
throw lastError(m_session);
}
if (messageTypeResult == OLM_MESSAGE_TYPE_PRE_KEY) {
return Message::PreKey;
}
return Message::General;
}
QByteArray QOlmSession::sessionId() const
{
const auto idMaxLength = olm_session_id_length(m_session);
QByteArray idBuffer(idMaxLength, '0');
const auto error = olm_session_id(m_session, reinterpret_cast<uint8_t *>(idBuffer.data()),
idBuffer.length());
if (error == olm_error()) {
throw lastError(m_session);
}
return idBuffer;
}
bool QOlmSession::hasReceivedMessage() const
{
return olm_session_has_received_message(m_session);
}
std::variant<bool, OlmError> QOlmSession::matchesInboundSession(Message &preKeyMessage)
{
Q_ASSERT(preKeyMessage.type() == Message::Type::PreKey);
QByteArray oneTimeKeyBuf(preKeyMessage.data());
const auto matchesResult = olm_matches_inbound_session(m_session, oneTimeKeyBuf.data(), oneTimeKeyBuf.length());
if (matchesResult == olm_error()) {
return lastError(m_session);
}
switch (matchesResult) {
case 0:
return false;
case 1:
return true;
default:
return OlmError::Unknown;
}
}
QOlmSession::QOlmSession(OlmSession *session)
: m_session(session)
{
}
#endif // Quotient_E2EE_ENABLED
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