bool AbstractSshPacket::isComplete() const
{
if (currentDataSize() < minPacketSize())
return false;
Q_ASSERT(4 + length() + macLength() >= currentDataSize());
return 4 + length() + macLength() == currentDataSize();
}
void SshIncomingPacket::consumeData(QByteArray &newData)
{
#ifdef CREATOR_SSH_DEBUG
qDebug("%s: current data size = %d, new data size = %d",
Q_FUNC_INFO, m_data.size(), newData.size());
#endif
if (isComplete() || newData.isEmpty())
return;
/*
* Until we have reached the minimum packet size, we cannot decrypt the
* length field.
*/
const quint32 minSize = minPacketSize();
if (currentDataSize() < minSize) {
const int bytesToTake
= qMin<quint32>(minSize - currentDataSize(), newData.size());
moveFirstBytes(m_data, newData, bytesToTake);
#ifdef CREATOR_SSH_DEBUG
qDebug("Took %d bytes from new data", bytesToTake);
#endif
if (currentDataSize() < minSize)
return;
}
if (4 + length() + macLength() < currentDataSize())
throw SSH_SERVER_EXCEPTION(SSH_DISCONNECT_PROTOCOL_ERROR, "Server sent invalid packet.");
const int bytesToTake
= qMin<quint32>(length() + 4 + macLength() - currentDataSize(),
newData.size());
moveFirstBytes(m_data, newData, bytesToTake);
#ifdef CREATOR_SSH_DEBUG
qDebug("Took %d bytes from new data", bytesToTake);
#endif
if (isComplete()) {
#ifdef CREATOR_SSH_DEBUG
qDebug("Message complete. Overall size: %u, payload size: %u",
m_data.size(), m_length - paddingLength() - 1);
#endif
decrypt();
++m_serverSeqNr;
}
}
void SshIncomingPacket::decrypt()
{
Q_ASSERT(isComplete());
const quint32 netDataLength = length() + 4;
m_decrypter.decrypt(m_data, cipherBlockSize(),
netDataLength - cipherBlockSize());
const QByteArray &mac = m_data.mid(netDataLength, macLength());
if (mac != generateMac(m_decrypter, m_serverSeqNr)) {
throw SSH_SERVER_EXCEPTION(SSH_DISCONNECT_MAC_ERROR,
"Message authentication failed.");
}
}
quint32 AbstractSshPacket::minPacketSize() const
{
return qMax<quint32>(cipherBlockSize(), 16) + macLength();
}