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// SPDX-FileCopyrightText: 2021 Alexey Andreyev <aa13q@ya.ru>
//
// SPDX-License-Identifier: LGPL-2.1-or-later
#include "qolmsession.h"
#include "e2ee/qolmutils.h"
#include "logging.h"
#include <cstring>
#include <olm/olm.h>
using namespace Quotient;
OlmErrorCode QOlmSession::lastErrorCode() const {
return olm_session_last_error_code(m_session);
}
const char* QOlmSession::lastError() const
{
return olm_session_last_error(m_session);
}
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()]);
}
QOlmExpected<QOlmSessionPtr> QOlmSession::createInbound(
QOlmAccount* account, const QOlmMessage& preKeyMessage, bool from,
const QString& theirIdentityKey)
{
if (preKeyMessage.type() != QOlmMessage::PreKey) {
qCCritical(E2EE) << "The message is not a pre-key; will try to create "
"the inbound session anyway";
}
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()) {
// FIXME: the QOlmSession object should be created earlier
const auto lastErr = olm_session_last_error_code(olmSession);
qCWarning(E2EE) << "Error when creating inbound session" << lastErr;
return lastErr;
}
return std::make_unique<QOlmSession>(olmSession);
}
QOlmExpected<QOlmSessionPtr> QOlmSession::createInboundSession(
QOlmAccount* account, const QOlmMessage& preKeyMessage)
{
return createInbound(account, preKeyMessage);
}
QOlmExpected<QOlmSessionPtr> QOlmSession::createInboundSessionFrom(
QOlmAccount* account, const QString& theirIdentityKey,
const QOlmMessage& preKeyMessage)
{
return createInbound(account, preKeyMessage, true, theirIdentityKey);
}
QOlmExpected<QOlmSessionPtr> QOlmSession::createOutboundSession(
QOlmAccount* account, const QByteArray& theirIdentityKey,
const QByteArray& theirOneTimeKey)
{
auto* olmOutboundSession = create();
if (const auto randomLength =
olm_create_outbound_session_random_length(olmOutboundSession);
olm_create_outbound_session(
olmOutboundSession, account->data(), theirIdentityKey.data(),
theirIdentityKey.length(), theirOneTimeKey.data(),
theirOneTimeKey.length(), RandomBuffer(randomLength), randomLength)
== olm_error()) {
// FIXME: the QOlmSession object should be created earlier
const auto lastErr = olm_session_last_error_code(olmOutboundSession);
QOLM_FAIL_OR_LOG_X(lastErr == OLM_NOT_ENOUGH_RANDOM,
"Failed to create an outbound Olm session",
olm_session_last_error(olmOutboundSession));
return lastErr;
}
return std::make_unique<QOlmSession>(olmOutboundSession);
}
QByteArray QOlmSession::pickle(const PicklingMode &mode) const
{
QByteArray pickledBuf(olm_pickle_session_length(m_session), '\0');
QByteArray key = toKey(mode);
if (olm_pickle_session(m_session, key.data(), key.length(),
pickledBuf.data(), pickledBuf.length())
== olm_error())
QOLM_INTERNAL_ERROR("Failed to pickle an Olm session");
key.clear();
return pickledBuf;
}
QOlmExpected<QOlmSessionPtr> QOlmSession::unpickle(QByteArray&& pickled,
const PicklingMode& mode)
{
auto *olmSession = create();
auto key = toKey(mode);
if (olm_unpickle_session(olmSession, key.data(), key.length(),
pickled.data(), pickled.length())
== olm_error()) {
// FIXME: the QOlmSession object should be created earlier
const auto errorCode = olm_session_last_error_code(olmSession);
QOLM_FAIL_OR_LOG_X(errorCode == OLM_OUTPUT_BUFFER_TOO_SMALL,
"Failed to unpickle an Olm session",
olm_session_last_error(olmSession));
return errorCode;
}
key.clear();
return std::make_unique<QOlmSession>(olmSession);
}
QOlmMessage QOlmSession::encrypt(const QByteArray& plaintext)
{
const auto messageMaxLength =
olm_encrypt_message_length(m_session, plaintext.length());
QByteArray messageBuf(messageMaxLength, '\0');
// NB: The type has to be calculated before calling olm_encrypt()
const auto messageType = olm_encrypt_message_type(m_session);
if (const auto randomLength = olm_encrypt_random_length(m_session);
olm_encrypt(m_session, plaintext.data(), plaintext.length(),
RandomBuffer(randomLength), randomLength, messageBuf.data(),
messageBuf.length())
== olm_error()) {
QOLM_INTERNAL_ERROR("Failed to encrypt the message");
}
return QOlmMessage(messageBuf, QOlmMessage::Type(messageType));
}
QOlmExpected<QByteArray> QOlmSession::decrypt(const QOlmMessage &message) const
{
const auto ciphertext = message.toCiphertext();
const auto messageTypeValue = message.type();
// 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, messageBuf.data(), messageBuf.length());
if (plaintextMaxLen == olm_error()) {
qWarning(E2EE) << "Couldn't calculate decrypted message length:"
<< lastError();
return lastErrorCode();
}
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, messageBuf2.data(),
messageBuf2.length(), plaintextBuf.data(), plaintextMaxLen);
if (plaintextResultLen == olm_error()) {
QOLM_FAIL_OR_LOG(OLM_OUTPUT_BUFFER_TOO_SMALL,
"Failed to decrypt the message");
return lastErrorCode();
}
plaintextBuf.truncate(plaintextResultLen);
return plaintextBuf;
}
QByteArray QOlmSession::sessionId() const
{
const auto idMaxLength = olm_session_id_length(m_session);
QByteArray idBuffer(idMaxLength, '\0');
if (olm_session_id(m_session, idBuffer.data(), idMaxLength) == olm_error())
QOLM_INTERNAL_ERROR("Failed to obtain Olm session id");
return idBuffer;
}
bool QOlmSession::hasReceivedMessage() const
{
return olm_session_has_received_message(m_session);
}
bool QOlmSession::matchesInboundSession(const QOlmMessage& preKeyMessage) const
{
Q_ASSERT(preKeyMessage.type() == QOlmMessage::Type::PreKey);
QByteArray oneTimeKeyBuf(preKeyMessage.data());
const auto maybeMatches =
olm_matches_inbound_session(m_session, oneTimeKeyBuf.data(),
oneTimeKeyBuf.length());
if (maybeMatches == olm_error())
qWarning(E2EE) << "Error matching an inbound session:" << lastError();
return maybeMatches == 1; // Any errors are treated as non-match
}
bool QOlmSession::matchesInboundSessionFrom(
const QString& theirIdentityKey, const QOlmMessage& preKeyMessage) const
{
const auto theirIdentityKeyBuf = theirIdentityKey.toUtf8();
auto oneTimeKeyMessageBuf = preKeyMessage.toCiphertext();
const auto maybeMatches = olm_matches_inbound_session_from(
m_session, theirIdentityKeyBuf.data(), theirIdentityKeyBuf.length(),
oneTimeKeyMessageBuf.data(), oneTimeKeyMessageBuf.length());
if (maybeMatches == olm_error())
qCWarning(E2EE) << "Error matching an inbound session:" << lastError();
return maybeMatches == 1;
}
QOlmSession::QOlmSession(OlmSession *session)
: m_session(session)
{}
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