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NTCP2.cpp
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NTCP2.cpp
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/*
* Copyright (c) 2013-2022, The PurpleI2P Project
*
* This file is part of Purple i2pd project and licensed under BSD3
*
* See full license text in LICENSE file at top of project tree
*
*/
#include <openssl/rand.h>
#include <openssl/sha.h>
#include <openssl/hmac.h>
#include <stdlib.h>
#include <vector>
#include "Log.h"
#include "I2PEndian.h"
#include "Crypto.h"
#include "Siphash.h"
#include "RouterContext.h"
#include "Transports.h"
#include "NetDb.hpp"
#include "NTCP2.h"
#include "HTTP.h"
#include "util.h"
#ifdef __linux__
#include <linux/in6.h>
#endif
namespace i2p
{
namespace transport
{
NTCP2Establisher::NTCP2Establisher ():
m_SessionConfirmedBuffer (nullptr)
{
}
NTCP2Establisher::~NTCP2Establisher ()
{
delete[] m_SessionConfirmedBuffer;
}
void NTCP2Establisher::KeyDerivationFunction1 (const uint8_t * pub, i2p::crypto::X25519Keys& priv, const uint8_t * rs, const uint8_t * epub)
{
i2p::crypto::InitNoiseXKState (*this, rs);
// h = SHA256(h || epub)
MixHash (epub, 32);
// x25519 between pub and priv
uint8_t inputKeyMaterial[32];
priv.Agree (pub, inputKeyMaterial);
MixKey (inputKeyMaterial);
}
void NTCP2Establisher::KDF1Alice ()
{
KeyDerivationFunction1 (m_RemoteStaticKey, *m_EphemeralKeys, m_RemoteStaticKey, GetPub ());
}
void NTCP2Establisher::KDF1Bob ()
{
KeyDerivationFunction1 (GetRemotePub (), i2p::context.GetNTCP2StaticKeys (), i2p::context.GetNTCP2StaticPublicKey (), GetRemotePub ());
}
void NTCP2Establisher::KeyDerivationFunction2 (const uint8_t * sessionRequest, size_t sessionRequestLen, const uint8_t * epub)
{
MixHash (sessionRequest + 32, 32); // encrypted payload
int paddingLength = sessionRequestLen - 64;
if (paddingLength > 0)
MixHash (sessionRequest + 64, paddingLength);
MixHash (epub, 32);
// x25519 between remote pub and ephemaral priv
uint8_t inputKeyMaterial[32];
m_EphemeralKeys->Agree (GetRemotePub (), inputKeyMaterial);
MixKey (inputKeyMaterial);
}
void NTCP2Establisher::KDF2Alice ()
{
KeyDerivationFunction2 (m_SessionRequestBuffer, m_SessionRequestBufferLen, GetRemotePub ());
}
void NTCP2Establisher::KDF2Bob ()
{
KeyDerivationFunction2 (m_SessionRequestBuffer, m_SessionRequestBufferLen, GetPub ());
}
void NTCP2Establisher::KDF3Alice ()
{
uint8_t inputKeyMaterial[32];
i2p::context.GetNTCP2StaticKeys ().Agree (GetRemotePub (), inputKeyMaterial);
MixKey (inputKeyMaterial);
}
void NTCP2Establisher::KDF3Bob ()
{
uint8_t inputKeyMaterial[32];
m_EphemeralKeys->Agree (m_RemoteStaticKey, inputKeyMaterial);
MixKey (inputKeyMaterial);
}
void NTCP2Establisher::CreateEphemeralKey ()
{
m_EphemeralKeys = i2p::transport::transports.GetNextX25519KeysPair ();
}
void NTCP2Establisher::CreateSessionRequestMessage ()
{
// create buffer and fill padding
auto paddingLength = rand () % (NTCP2_SESSION_REQUEST_MAX_SIZE - 64); // message length doesn't exceed 287 bytes
m_SessionRequestBufferLen = paddingLength + 64;
RAND_bytes (m_SessionRequestBuffer + 64, paddingLength);
// encrypt X
i2p::crypto::CBCEncryption encryption;
encryption.SetKey (m_RemoteIdentHash);
encryption.SetIV (m_IV);
encryption.Encrypt (GetPub (), 32, m_SessionRequestBuffer); // X
encryption.GetIV (m_IV); // save IV for SessionCreated
// encryption key for next block
KDF1Alice ();
// fill options
uint8_t options[32]; // actual options size is 16 bytes
memset (options, 0, 16);
options[0] = i2p::context.GetNetID (); // network ID
options[1] = 2; // ver
htobe16buf (options + 2, paddingLength); // padLen
// m3p2Len
auto bufLen = i2p::context.GetRouterInfo ().GetBufferLen ();
m3p2Len = bufLen + 4 + 16; // (RI header + RI + MAC for now) TODO: implement options
htobe16buf (options + 4, m3p2Len);
// fill m3p2 payload (RouterInfo block)
m_SessionConfirmedBuffer = new uint8_t[m3p2Len + 48]; // m3p1 is 48 bytes
uint8_t * m3p2 = m_SessionConfirmedBuffer + 48;
m3p2[0] = eNTCP2BlkRouterInfo; // block
htobe16buf (m3p2 + 1, bufLen + 1); // flag + RI
m3p2[3] = 0; // flag
memcpy (m3p2 + 4, i2p::context.GetRouterInfo ().GetBuffer (), bufLen); // TODO: own RI should be protected by mutex
// 2 bytes reserved
htobe32buf (options + 8, i2p::util::GetSecondsSinceEpoch ()); // tsA
// 4 bytes reserved
// sign and encrypt options, use m_H as AD
uint8_t nonce[12];
memset (nonce, 0, 12); // set nonce to zero
i2p::crypto::AEADChaCha20Poly1305 (options, 16, GetH (), 32, GetK (), nonce, m_SessionRequestBuffer + 32, 32, true); // encrypt
}
void NTCP2Establisher::CreateSessionCreatedMessage ()
{
auto paddingLen = rand () % (NTCP2_SESSION_CREATED_MAX_SIZE - 64);
m_SessionCreatedBufferLen = paddingLen + 64;
RAND_bytes (m_SessionCreatedBuffer + 64, paddingLen);
// encrypt Y
i2p::crypto::CBCEncryption encryption;
encryption.SetKey (i2p::context.GetIdentHash ());
encryption.SetIV (m_IV);
encryption.Encrypt (GetPub (), 32, m_SessionCreatedBuffer); // Y
// encryption key for next block (m_K)
KDF2Bob ();
uint8_t options[16];
memset (options, 0, 16);
htobe16buf (options + 2, paddingLen); // padLen
htobe32buf (options + 8, i2p::util::GetSecondsSinceEpoch ()); // tsB
// sign and encrypt options, use m_H as AD
uint8_t nonce[12];
memset (nonce, 0, 12); // set nonce to zero
i2p::crypto::AEADChaCha20Poly1305 (options, 16, GetH (), 32, GetK (), nonce, m_SessionCreatedBuffer + 32, 32, true); // encrypt
}
void NTCP2Establisher::CreateSessionConfirmedMessagePart1 (const uint8_t * nonce)
{
// update AD
MixHash (m_SessionCreatedBuffer + 32, 32); // encrypted payload
int paddingLength = m_SessionCreatedBufferLen - 64;
if (paddingLength > 0)
MixHash (m_SessionCreatedBuffer + 64, paddingLength);
// part1 48 bytes
i2p::crypto::AEADChaCha20Poly1305 (i2p::context.GetNTCP2StaticPublicKey (), 32, GetH (), 32, GetK (), nonce, m_SessionConfirmedBuffer, 48, true); // encrypt
}
void NTCP2Establisher::CreateSessionConfirmedMessagePart2 (const uint8_t * nonce)
{
// part 2
// update AD again
MixHash (m_SessionConfirmedBuffer, 48);
// encrypt m3p2, it must be filled in SessionRequest
KDF3Alice ();
uint8_t * m3p2 = m_SessionConfirmedBuffer + 48;
i2p::crypto::AEADChaCha20Poly1305 (m3p2, m3p2Len - 16, GetH (), 32, GetK (), nonce, m3p2, m3p2Len, true); // encrypt
// update h again
MixHash (m3p2, m3p2Len); //h = SHA256(h || ciphertext)
}
bool NTCP2Establisher::ProcessSessionRequestMessage (uint16_t& paddingLen, bool& clockSkew)
{
clockSkew = false;
// decrypt X
i2p::crypto::CBCDecryption decryption;
decryption.SetKey (i2p::context.GetIdentHash ());
decryption.SetIV (i2p::context.GetNTCP2IV ());
decryption.Decrypt (m_SessionRequestBuffer, 32, GetRemotePub ());
decryption.GetIV (m_IV); // save IV for SessionCreated
// decryption key for next block
KDF1Bob ();
// verify MAC and decrypt options block (32 bytes), use m_H as AD
uint8_t nonce[12], options[16];
memset (nonce, 0, 12); // set nonce to zero
if (i2p::crypto::AEADChaCha20Poly1305 (m_SessionRequestBuffer + 32, 16, GetH (), 32, GetK (), nonce, options, 16, false)) // decrypt
{
// options
if (options[0] && options[0] != i2p::context.GetNetID ())
{
LogPrint (eLogWarning, "NTCP2: SessionRequest networkID ", (int)options[0], " mismatch. Expected ", i2p::context.GetNetID ());
return false;
}
if (options[1] == 2) // ver is always 2
{
paddingLen = bufbe16toh (options + 2);
m_SessionRequestBufferLen = paddingLen + 64;
m3p2Len = bufbe16toh (options + 4);
if (m3p2Len < 16)
{
LogPrint (eLogWarning, "NTCP2: SessionRequest m3p2len=", m3p2Len, " is too short");
return false;
}
// check timestamp
auto ts = i2p::util::GetSecondsSinceEpoch ();
uint32_t tsA = bufbe32toh (options + 8);
if (tsA < ts - NTCP2_CLOCK_SKEW || tsA > ts + NTCP2_CLOCK_SKEW)
{
LogPrint (eLogWarning, "NTCP2: SessionRequest time difference ", (int)(ts - tsA), " exceeds clock skew");
clockSkew = true;
// we send SessionCreate to let Alice know our time and then close session
}
}
else
{
LogPrint (eLogWarning, "NTCP2: SessionRequest version mismatch ", (int)options[1]);
return false;
}
}
else
{
LogPrint (eLogWarning, "NTCP2: SessionRequest AEAD verification failed ");
return false;
}
return true;
}
bool NTCP2Establisher::ProcessSessionCreatedMessage (uint16_t& paddingLen)
{
m_SessionCreatedBufferLen = 64;
// decrypt Y
i2p::crypto::CBCDecryption decryption;
decryption.SetKey (m_RemoteIdentHash);
decryption.SetIV (m_IV);
decryption.Decrypt (m_SessionCreatedBuffer, 32, GetRemotePub ());
// decryption key for next block (m_K)
KDF2Alice ();
// decrypt and verify MAC
uint8_t payload[16];
uint8_t nonce[12];
memset (nonce, 0, 12); // set nonce to zero
if (i2p::crypto::AEADChaCha20Poly1305 (m_SessionCreatedBuffer + 32, 16, GetH (), 32, GetK (), nonce, payload, 16, false)) // decrypt
{
// options
paddingLen = bufbe16toh(payload + 2);
// check timestamp
auto ts = i2p::util::GetSecondsSinceEpoch ();
uint32_t tsB = bufbe32toh (payload + 8);
if (tsB < ts - NTCP2_CLOCK_SKEW || tsB > ts + NTCP2_CLOCK_SKEW)
{
LogPrint (eLogWarning, "NTCP2: SessionCreated time difference ", (int)(ts - tsB), " exceeds clock skew");
return false;
}
}
else
{
LogPrint (eLogWarning, "NTCP2: SessionCreated AEAD verification failed ");
return false;
}
return true;
}
bool NTCP2Establisher::ProcessSessionConfirmedMessagePart1 (const uint8_t * nonce)
{
// update AD
MixHash (m_SessionCreatedBuffer + 32, 32); // encrypted payload
int paddingLength = m_SessionCreatedBufferLen - 64;
if (paddingLength > 0)
MixHash (m_SessionCreatedBuffer + 64, paddingLength);
if (!i2p::crypto::AEADChaCha20Poly1305 (m_SessionConfirmedBuffer, 32, GetH (), 32, GetK (), nonce, m_RemoteStaticKey, 32, false)) // decrypt S
{
LogPrint (eLogWarning, "NTCP2: SessionConfirmed Part1 AEAD verification failed ");
return false;
}
return true;
}
bool NTCP2Establisher::ProcessSessionConfirmedMessagePart2 (const uint8_t * nonce, uint8_t * m3p2Buf)
{
// update AD again
MixHash (m_SessionConfirmedBuffer, 48);
KDF3Bob ();
if (i2p::crypto::AEADChaCha20Poly1305 (m_SessionConfirmedBuffer + 48, m3p2Len - 16, GetH (), 32, GetK (), nonce, m3p2Buf, m3p2Len - 16, false)) // decrypt
// caclulate new h again for KDF data
MixHash (m_SessionConfirmedBuffer + 48, m3p2Len); // h = SHA256(h || ciphertext)
else
{
LogPrint (eLogWarning, "NTCP2: SessionConfirmed Part2 AEAD verification failed ");
return false;
}
return true;
}
NTCP2Session::NTCP2Session (NTCP2Server& server, std::shared_ptr<const i2p::data::RouterInfo> in_RemoteRouter,
std::shared_ptr<const i2p::data::RouterInfo::Address> addr):
TransportSession (in_RemoteRouter, NTCP2_ESTABLISH_TIMEOUT),
m_Server (server), m_Socket (m_Server.GetService ()),
m_IsEstablished (false), m_IsTerminated (false),
m_Establisher (new NTCP2Establisher),
#if OPENSSL_SIPHASH
m_SendMDCtx(nullptr), m_ReceiveMDCtx (nullptr),
#else
m_SendSipKey (nullptr), m_ReceiveSipKey (nullptr),
#endif
m_NextReceivedLen (0), m_NextReceivedBuffer (nullptr), m_NextSendBuffer (nullptr),
m_NextReceivedBufferSize (0), m_ReceiveSequenceNumber (0), m_SendSequenceNumber (0),
m_IsSending (false), m_IsReceiving (false), m_NextPaddingSize (16)
{
if (in_RemoteRouter) // Alice
{
m_Establisher->m_RemoteIdentHash = GetRemoteIdentity ()->GetIdentHash ();
if (addr)
{
memcpy (m_Establisher->m_RemoteStaticKey, addr->s, 32);
memcpy (m_Establisher->m_IV, addr->i, 16);
m_RemoteEndpoint = boost::asio::ip::tcp::endpoint (addr->host, addr->port);
}
else
LogPrint (eLogWarning, "NTCP2: Missing NTCP2 address");
}
m_NextRouterInfoResendTime = i2p::util::GetSecondsSinceEpoch () + NTCP2_ROUTERINFO_RESEND_INTERVAL +
rand ()%NTCP2_ROUTERINFO_RESEND_INTERVAL_THRESHOLD;
}
NTCP2Session::~NTCP2Session ()
{
delete[] m_NextReceivedBuffer;
delete[] m_NextSendBuffer;
#if OPENSSL_SIPHASH
if (m_SendMDCtx) EVP_MD_CTX_destroy (m_SendMDCtx);
if (m_ReceiveMDCtx) EVP_MD_CTX_destroy (m_ReceiveMDCtx);
#endif
}
void NTCP2Session::Terminate ()
{
if (!m_IsTerminated)
{
m_IsTerminated = true;
m_IsEstablished = false;
boost::system::error_code ec;
m_Socket.shutdown(boost::asio::ip::tcp::socket::shutdown_both, ec);
if (ec)
LogPrint (eLogDebug, "NTCP2: Couldn't shutdown socket: ", ec.message ());
m_Socket.close ();
transports.PeerDisconnected (shared_from_this ());
m_Server.RemoveNTCP2Session (shared_from_this ());
m_SendQueue.clear ();
LogPrint (eLogDebug, "NTCP2: Session terminated");
}
}
void NTCP2Session::TerminateByTimeout ()
{
SendTerminationAndTerminate (eNTCP2IdleTimeout);
}
void NTCP2Session::Done ()
{
m_Server.GetService ().post (std::bind (&NTCP2Session::Terminate, shared_from_this ()));
}
void NTCP2Session::Established ()
{
m_IsEstablished = true;
m_Establisher.reset (nullptr);
SetTerminationTimeout (NTCP2_TERMINATION_TIMEOUT);
transports.PeerConnected (shared_from_this ());
}
void NTCP2Session::CreateNonce (uint64_t seqn, uint8_t * nonce)
{
memset (nonce, 0, 4);
htole64buf (nonce + 4, seqn);
}
void NTCP2Session::CreateNextReceivedBuffer (size_t size)
{
if (m_NextReceivedBuffer)
{
if (size <= m_NextReceivedBufferSize)
return; // buffer is good, do nothing
else
delete[] m_NextReceivedBuffer;
}
m_NextReceivedBuffer = new uint8_t[size];
m_NextReceivedBufferSize = size;
}
void NTCP2Session::DeleteNextReceiveBuffer (uint64_t ts)
{
if (m_NextReceivedBuffer && !m_IsReceiving &&
ts > m_LastActivityTimestamp + NTCP2_RECEIVE_BUFFER_DELETION_TIMEOUT)
{
delete[] m_NextReceivedBuffer;
m_NextReceivedBuffer = nullptr;
m_NextReceivedBufferSize = 0;
}
}
void NTCP2Session::KeyDerivationFunctionDataPhase ()
{
uint8_t k[64];
i2p::crypto::HKDF (m_Establisher->GetCK (), nullptr, 0, "", k); // k_ab, k_ba = HKDF(ck, zerolen)
memcpy (m_Kab, k, 32); memcpy (m_Kba, k + 32, 32);
uint8_t master[32];
i2p::crypto::HKDF (m_Establisher->GetCK (), nullptr, 0, "ask", master, 32); // ask_master = HKDF(ck, zerolen, info="ask")
uint8_t h[39];
memcpy (h, m_Establisher->GetH (), 32);
memcpy (h + 32, "siphash", 7);
i2p::crypto::HKDF (master, h, 39, "", master, 32); // sip_master = HKDF(ask_master, h || "siphash")
i2p::crypto::HKDF (master, nullptr, 0, "", k); // sipkeys_ab, sipkeys_ba = HKDF(sip_master, zerolen)
memcpy (m_Sipkeysab, k, 32); memcpy (m_Sipkeysba, k + 32, 32);
}
void NTCP2Session::SendSessionRequest ()
{
m_Establisher->CreateSessionRequestMessage ();
// send message
boost::asio::async_write (m_Socket, boost::asio::buffer (m_Establisher->m_SessionRequestBuffer, m_Establisher->m_SessionRequestBufferLen), boost::asio::transfer_all (),
std::bind(&NTCP2Session::HandleSessionRequestSent, shared_from_this (), std::placeholders::_1, std::placeholders::_2));
}
void NTCP2Session::HandleSessionRequestSent (const boost::system::error_code& ecode, std::size_t bytes_transferred)
{
(void) bytes_transferred;
if (ecode)
{
LogPrint (eLogWarning, "NTCP2: Couldn't send SessionRequest message: ", ecode.message ());
Terminate ();
}
else
{
// we receive first 64 bytes (32 Y, and 32 ChaCha/Poly frame) first
boost::asio::async_read (m_Socket, boost::asio::buffer(m_Establisher->m_SessionCreatedBuffer, 64), boost::asio::transfer_all (),
std::bind(&NTCP2Session::HandleSessionCreatedReceived, shared_from_this (), std::placeholders::_1, std::placeholders::_2));
}
}
void NTCP2Session::HandleSessionRequestReceived (const boost::system::error_code& ecode, std::size_t bytes_transferred)
{
(void) bytes_transferred;
if (ecode)
{
LogPrint (eLogWarning, "NTCP2: SessionRequest read error: ", ecode.message ());
Terminate ();
}
else
{
LogPrint (eLogDebug, "NTCP2: SessionRequest received ", bytes_transferred);
uint16_t paddingLen = 0;
bool clockSkew = false;
if (m_Establisher->ProcessSessionRequestMessage (paddingLen, clockSkew))
{
if (clockSkew)
{
// we don't care about padding, send SessionCreated and close session
SendSessionCreated ();
m_Server.GetService ().post (std::bind (&NTCP2Session::Terminate, shared_from_this ()));
}
else if (paddingLen > 0)
{
if (paddingLen <= NTCP2_SESSION_REQUEST_MAX_SIZE - 64) // session request is 287 bytes max
{
boost::asio::async_read (m_Socket, boost::asio::buffer(m_Establisher->m_SessionRequestBuffer + 64, paddingLen), boost::asio::transfer_all (),
std::bind(&NTCP2Session::HandleSessionRequestPaddingReceived, shared_from_this (), std::placeholders::_1, std::placeholders::_2));
}
else
{
LogPrint (eLogWarning, "NTCP2: SessionRequest padding length ", (int)paddingLen, " is too long");
Terminate ();
}
}
else
SendSessionCreated ();
}
else
Terminate ();
}
}
void NTCP2Session::HandleSessionRequestPaddingReceived (const boost::system::error_code& ecode, std::size_t bytes_transferred)
{
if (ecode)
{
LogPrint (eLogWarning, "NTCP2: SessionRequest padding read error: ", ecode.message ());
Terminate ();
}
else
SendSessionCreated ();
}
void NTCP2Session::SendSessionCreated ()
{
m_Establisher->CreateSessionCreatedMessage ();
// send message
boost::asio::async_write (m_Socket, boost::asio::buffer (m_Establisher->m_SessionCreatedBuffer, m_Establisher->m_SessionCreatedBufferLen), boost::asio::transfer_all (),
std::bind(&NTCP2Session::HandleSessionCreatedSent, shared_from_this (), std::placeholders::_1, std::placeholders::_2));
}
void NTCP2Session::HandleSessionCreatedReceived (const boost::system::error_code& ecode, std::size_t bytes_transferred)
{
if (ecode)
{
LogPrint (eLogWarning, "NTCP2: SessionCreated read error: ", ecode.message ());
Terminate ();
}
else
{
LogPrint (eLogDebug, "NTCP2: SessionCreated received ", bytes_transferred);
uint16_t paddingLen = 0;
if (m_Establisher->ProcessSessionCreatedMessage (paddingLen))
{
if (paddingLen > 0)
{
if (paddingLen <= NTCP2_SESSION_CREATED_MAX_SIZE - 64) // session created is 287 bytes max
{
boost::asio::async_read (m_Socket, boost::asio::buffer(m_Establisher->m_SessionCreatedBuffer + 64, paddingLen), boost::asio::transfer_all (),
std::bind(&NTCP2Session::HandleSessionCreatedPaddingReceived, shared_from_this (), std::placeholders::_1, std::placeholders::_2));
}
else
{
LogPrint (eLogWarning, "NTCP2: SessionCreated padding length ", (int)paddingLen, " is too long");
Terminate ();
}
}
else
SendSessionConfirmed ();
}
else
Terminate ();
}
}
void NTCP2Session::HandleSessionCreatedPaddingReceived (const boost::system::error_code& ecode, std::size_t bytes_transferred)
{
if (ecode)
{
LogPrint (eLogWarning, "NTCP2: SessionCreated padding read error: ", ecode.message ());
Terminate ();
}
else
{
m_Establisher->m_SessionCreatedBufferLen += bytes_transferred;
SendSessionConfirmed ();
}
}
void NTCP2Session::SendSessionConfirmed ()
{
uint8_t nonce[12];
CreateNonce (1, nonce); // set nonce to 1
m_Establisher->CreateSessionConfirmedMessagePart1 (nonce);
memset (nonce, 0, 12); // set nonce back to 0
m_Establisher->CreateSessionConfirmedMessagePart2 (nonce);
// send message
boost::asio::async_write (m_Socket, boost::asio::buffer (m_Establisher->m_SessionConfirmedBuffer, m_Establisher->m3p2Len + 48), boost::asio::transfer_all (),
std::bind(&NTCP2Session::HandleSessionConfirmedSent, shared_from_this (), std::placeholders::_1, std::placeholders::_2));
}
void NTCP2Session::HandleSessionConfirmedSent (const boost::system::error_code& ecode, std::size_t bytes_transferred)
{
(void) bytes_transferred;
if (ecode)
{
LogPrint (eLogWarning, "NTCP2: Couldn't send SessionConfirmed message: ", ecode.message ());
Terminate ();
}
else
{
LogPrint (eLogDebug, "NTCP2: SessionConfirmed sent");
KeyDerivationFunctionDataPhase ();
// Alice data phase keys
m_SendKey = m_Kab;
m_ReceiveKey = m_Kba;
SetSipKeys (m_Sipkeysab, m_Sipkeysba);
memcpy (m_ReceiveIV.buf, m_Sipkeysba + 16, 8);
memcpy (m_SendIV.buf, m_Sipkeysab + 16, 8);
Established ();
ReceiveLength ();
// TODO: remove
// m_SendQueue.push_back (CreateDeliveryStatusMsg (1));
// SendQueue ();
}
}
void NTCP2Session::HandleSessionCreatedSent (const boost::system::error_code& ecode, std::size_t bytes_transferred)
{
(void) bytes_transferred;
if (ecode)
{
LogPrint (eLogWarning, "NTCP2: Couldn't send SessionCreated message: ", ecode.message ());
Terminate ();
}
else
{
LogPrint (eLogDebug, "NTCP2: SessionCreated sent");
m_Establisher->m_SessionConfirmedBuffer = new uint8_t[m_Establisher->m3p2Len + 48];
boost::asio::async_read (m_Socket, boost::asio::buffer(m_Establisher->m_SessionConfirmedBuffer, m_Establisher->m3p2Len + 48), boost::asio::transfer_all (),
std::bind(&NTCP2Session::HandleSessionConfirmedReceived , shared_from_this (), std::placeholders::_1, std::placeholders::_2));
}
}
void NTCP2Session::HandleSessionConfirmedReceived (const boost::system::error_code& ecode, std::size_t bytes_transferred)
{
if (ecode)
{
LogPrint (eLogWarning, "NTCP2: SessionConfirmed read error: ", ecode.message ());
Terminate ();
}
else
{
LogPrint (eLogDebug, "NTCP2: SessionConfirmed received");
// part 1
uint8_t nonce[12];
CreateNonce (1, nonce);
if (m_Establisher->ProcessSessionConfirmedMessagePart1 (nonce))
{
// part 2
std::vector<uint8_t> buf(m_Establisher->m3p2Len - 16); // -MAC
memset (nonce, 0, 12); // set nonce to 0 again
if (m_Establisher->ProcessSessionConfirmedMessagePart2 (nonce, buf.data ()))
{
KeyDerivationFunctionDataPhase ();
// Bob data phase keys
m_SendKey = m_Kba;
m_ReceiveKey = m_Kab;
SetSipKeys (m_Sipkeysba, m_Sipkeysab);
memcpy (m_ReceiveIV.buf, m_Sipkeysab + 16, 8);
memcpy (m_SendIV.buf, m_Sipkeysba + 16, 8);
// payload
// process RI
if (buf[0] != eNTCP2BlkRouterInfo)
{
LogPrint (eLogWarning, "NTCP2: Unexpected block ", (int)buf[0], " in SessionConfirmed");
Terminate ();
return;
}
auto size = bufbe16toh (buf.data () + 1);
if (size > buf.size () - 3)
{
LogPrint (eLogError, "NTCP2: Unexpected RouterInfo size ", size, " in SessionConfirmed");
Terminate ();
return;
}
// TODO: check flag
i2p::data::RouterInfo ri (buf.data () + 4, size - 1); // 1 byte block type + 2 bytes size + 1 byte flag
if (ri.IsUnreachable ())
{
LogPrint (eLogError, "NTCP2: Signature verification failed in SessionConfirmed");
SendTerminationAndTerminate (eNTCP2RouterInfoSignatureVerificationFail);
return;
}
if (i2p::util::GetMillisecondsSinceEpoch () > ri.GetTimestamp () + i2p::data::NETDB_MIN_EXPIRATION_TIMEOUT*1000LL) // 90 minutes
{
LogPrint (eLogError, "NTCP2: RouterInfo is too old in SessionConfirmed");
SendTerminationAndTerminate (eNTCP2Message3Error);
return;
}
auto addr = ri.GetNTCP2AddressWithStaticKey (m_Establisher->m_RemoteStaticKey);
if (!addr)
{
LogPrint (eLogError, "NTCP2: No NTCP2 address with static key found in SessionConfirmed");
Terminate ();
return;
}
i2p::data::netdb.PostI2NPMsg (CreateI2NPMessage (eI2NPDummyMsg, buf.data () + 3, size)); // TODO: should insert ri and not parse it twice
// TODO: process options
// ready to communicate
auto existing = i2p::data::netdb.FindRouter (ri.GetRouterIdentity ()->GetIdentHash ()); // check if exists already
SetRemoteIdentity (existing ? existing->GetRouterIdentity () : ri.GetRouterIdentity ());
if (m_Server.AddNTCP2Session (shared_from_this (), true))
{
Established ();
ReceiveLength ();
}
else
Terminate ();
}
else
Terminate ();
}
else
Terminate ();
}
}
void NTCP2Session::SetSipKeys (const uint8_t * sendSipKey, const uint8_t * receiveSipKey)
{
#if OPENSSL_SIPHASH
EVP_PKEY * sipKey = EVP_PKEY_new_raw_private_key (EVP_PKEY_SIPHASH, nullptr, sendSipKey, 16);
m_SendMDCtx = EVP_MD_CTX_create ();
EVP_PKEY_CTX *ctx = nullptr;
EVP_DigestSignInit (m_SendMDCtx, &ctx, nullptr, nullptr, sipKey);
EVP_PKEY_CTX_ctrl (ctx, -1, EVP_PKEY_OP_SIGNCTX, EVP_PKEY_CTRL_SET_DIGEST_SIZE, 8, nullptr);
EVP_PKEY_free (sipKey);
sipKey = EVP_PKEY_new_raw_private_key (EVP_PKEY_SIPHASH, nullptr, receiveSipKey, 16);
m_ReceiveMDCtx = EVP_MD_CTX_create ();
ctx = nullptr;
EVP_DigestSignInit (m_ReceiveMDCtx, &ctx, NULL, NULL, sipKey);
EVP_PKEY_CTX_ctrl (ctx, -1, EVP_PKEY_OP_SIGNCTX, EVP_PKEY_CTRL_SET_DIGEST_SIZE, 8, nullptr);
EVP_PKEY_free (sipKey);
#else
m_SendSipKey = sendSipKey;
m_ReceiveSipKey = receiveSipKey;
#endif
}
void NTCP2Session::ClientLogin ()
{
m_Establisher->CreateEphemeralKey ();
SendSessionRequest ();
}
void NTCP2Session::ServerLogin ()
{
m_Establisher->CreateEphemeralKey ();
boost::asio::async_read (m_Socket, boost::asio::buffer(m_Establisher->m_SessionRequestBuffer, 64), boost::asio::transfer_all (),
std::bind(&NTCP2Session::HandleSessionRequestReceived, shared_from_this (),
std::placeholders::_1, std::placeholders::_2));
}
void NTCP2Session::ReceiveLength ()
{
if (IsTerminated ()) return;
#ifdef __linux__
const int one = 1;
setsockopt(m_Socket.native_handle(), IPPROTO_TCP, TCP_QUICKACK, &one, sizeof(one));
#endif
boost::asio::async_read (m_Socket, boost::asio::buffer(&m_NextReceivedLen, 2), boost::asio::transfer_all (),
std::bind(&NTCP2Session::HandleReceivedLength, shared_from_this (), std::placeholders::_1, std::placeholders::_2));
}
void NTCP2Session::HandleReceivedLength (const boost::system::error_code& ecode, std::size_t bytes_transferred)
{
if (ecode)
{
if (ecode != boost::asio::error::operation_aborted)
LogPrint (eLogWarning, "NTCP2: Receive length read error: ", ecode.message ());
Terminate ();
}
else
{
#if OPENSSL_SIPHASH
EVP_DigestSignInit (m_ReceiveMDCtx, nullptr, nullptr, nullptr, nullptr);
EVP_DigestSignUpdate (m_ReceiveMDCtx, m_ReceiveIV.buf, 8);
size_t l = 8;
EVP_DigestSignFinal (m_ReceiveMDCtx, m_ReceiveIV.buf, &l);
#else
i2p::crypto::Siphash<8> (m_ReceiveIV.buf, m_ReceiveIV.buf, 8, m_ReceiveSipKey);
#endif
// m_NextReceivedLen comes from the network in BigEndian
m_NextReceivedLen = be16toh (m_NextReceivedLen) ^ le16toh (m_ReceiveIV.key);
LogPrint (eLogDebug, "NTCP2: Received length ", m_NextReceivedLen);
if (m_NextReceivedLen >= 16)
{
CreateNextReceivedBuffer (m_NextReceivedLen);
boost::system::error_code ec;
size_t moreBytes = m_Socket.available(ec);
if (!ec && moreBytes >= m_NextReceivedLen)
{
// read and process message immediately if available
moreBytes = boost::asio::read (m_Socket, boost::asio::buffer(m_NextReceivedBuffer, m_NextReceivedLen), boost::asio::transfer_all (), ec);
HandleReceived (ec, moreBytes);
}
else
Receive ();
}
else
{
LogPrint (eLogError, "NTCP2: Received length ", m_NextReceivedLen, " is too short");
Terminate ();
}
}
}
void NTCP2Session::Receive ()
{
if (IsTerminated ()) return;
#ifdef __linux__
const int one = 1;
setsockopt(m_Socket.native_handle(), IPPROTO_TCP, TCP_QUICKACK, &one, sizeof(one));
#endif
m_IsReceiving = true;
boost::asio::async_read (m_Socket, boost::asio::buffer(m_NextReceivedBuffer, m_NextReceivedLen), boost::asio::transfer_all (),
std::bind(&NTCP2Session::HandleReceived, shared_from_this (), std::placeholders::_1, std::placeholders::_2));
}
void NTCP2Session::HandleReceived (const boost::system::error_code& ecode, std::size_t bytes_transferred)
{
if (ecode)
{
if (ecode != boost::asio::error::operation_aborted)
LogPrint (eLogWarning, "NTCP2: Receive read error: ", ecode.message ());
Terminate ();
}
else
{
m_LastActivityTimestamp = i2p::util::GetSecondsSinceEpoch ();
m_NumReceivedBytes += bytes_transferred + 2; // + length
i2p::transport::transports.UpdateReceivedBytes (bytes_transferred);
uint8_t nonce[12];
CreateNonce (m_ReceiveSequenceNumber, nonce); m_ReceiveSequenceNumber++;
if (i2p::crypto::AEADChaCha20Poly1305 (m_NextReceivedBuffer, m_NextReceivedLen-16, nullptr, 0, m_ReceiveKey, nonce, m_NextReceivedBuffer, m_NextReceivedLen, false))
{
LogPrint (eLogDebug, "NTCP2: Received message decrypted");
ProcessNextFrame (m_NextReceivedBuffer, m_NextReceivedLen-16);
m_IsReceiving = false;
ReceiveLength ();
}
else
{
LogPrint (eLogWarning, "NTCP2: Received AEAD verification failed ");
SendTerminationAndTerminate (eNTCP2DataPhaseAEADFailure);
}
}
}
void NTCP2Session::ProcessNextFrame (const uint8_t * frame, size_t len)
{
size_t offset = 0;
while (offset < len)
{
uint8_t blk = frame[offset];
offset++;
auto size = bufbe16toh (frame + offset);
offset += 2;
LogPrint (eLogDebug, "NTCP2: Block type ", (int)blk, " of size ", size);
if (size > len)
{
LogPrint (eLogError, "NTCP2: Unexpected block length ", size);
break;
}
switch (blk)
{
case eNTCP2BlkDateTime:
LogPrint (eLogDebug, "NTCP2: Datetime");
break;
case eNTCP2BlkOptions:
LogPrint (eLogDebug, "NTCP2: Options");
break;
case eNTCP2BlkRouterInfo:
{
LogPrint (eLogDebug, "NTCP2: RouterInfo flag=", (int)frame[offset]);
i2p::data::netdb.PostI2NPMsg (CreateI2NPMessage (eI2NPDummyMsg, frame + offset, size));
break;
}
case eNTCP2BlkI2NPMessage:
{
LogPrint (eLogDebug, "NTCP2: I2NP");
if (size > I2NP_MAX_MESSAGE_SIZE)
{
LogPrint (eLogError, "NTCP2: I2NP block is too long ", size);
break;
}
auto nextMsg = (frame[offset] == eI2NPTunnelData) ? NewI2NPTunnelMessage (true) : NewI2NPMessage (size);
nextMsg->len = nextMsg->offset + size + 7; // 7 more bytes for full I2NP header
if (nextMsg->len <= nextMsg->maxLen)
{
memcpy (nextMsg->GetNTCP2Header (), frame + offset, size);
nextMsg->FromNTCP2 ();
m_Handler.PutNextMessage (std::move (nextMsg));
}
else
LogPrint (eLogError, "NTCP2: I2NP block is too long for I2NP message");
break;
}
case eNTCP2BlkTermination:
if (size >= 9)
{
LogPrint (eLogDebug, "NTCP2: Termination. reason=", (int)(frame[offset + 8]));
Terminate ();
}
else
LogPrint (eLogWarning, "NTCP2: Unexpected termination block size ", size);
break;
case eNTCP2BlkPadding:
LogPrint (eLogDebug, "NTCP2: Padding");
break;
default:
LogPrint (eLogWarning, "NTCP2: Unknown block type ", (int)blk);
}
offset += size;
}
m_Handler.Flush ();
}
void NTCP2Session::SetNextSentFrameLength (size_t frameLen, uint8_t * lengthBuf)
{
#if OPENSSL_SIPHASH
EVP_DigestSignInit (m_SendMDCtx, nullptr, nullptr, nullptr, nullptr);
EVP_DigestSignUpdate (m_SendMDCtx, m_SendIV.buf, 8);
size_t l = 8;
EVP_DigestSignFinal (m_SendMDCtx, m_SendIV.buf, &l);
#else
i2p::crypto::Siphash<8> (m_SendIV.buf, m_SendIV.buf, 8, m_SendSipKey);
#endif
// length must be in BigEndian
htobe16buf (lengthBuf, frameLen ^ le16toh (m_SendIV.key));
LogPrint (eLogDebug, "NTCP2: Sent length ", frameLen);
}
void NTCP2Session::SendI2NPMsgs (std::vector<std::shared_ptr<I2NPMessage> >& msgs)
{
if (msgs.empty () || IsTerminated ()) return;
size_t totalLen = 0;
std::vector<std::pair<uint8_t *, size_t> > encryptBufs;
std::vector<boost::asio::const_buffer> bufs;
std::shared_ptr<I2NPMessage> first;
uint8_t * macBuf = nullptr;
for (auto& it: msgs)
{
it->ToNTCP2 ();
auto buf = it->GetNTCP2Header ();
auto len = it->GetNTCP2Length ();
// block header
buf -= 3;
buf[0] = eNTCP2BlkI2NPMessage; // blk
htobe16buf (buf + 1, len); // size
len += 3;
totalLen += len;
encryptBufs.push_back ( {buf, len} );
if (&it == &msgs.front ()) // first message
{
// allocate two bytes for length
buf -= 2; len += 2;
first = it;
}
if (&it == &msgs.back () && it->len + 16 < it->maxLen) // last message
{
// if it's long enough we add padding and MAC to it
// create padding block
auto paddingLen = CreatePaddingBlock (totalLen, buf + len, it->maxLen - it->len - 16);
if (paddingLen)
{
encryptBufs.push_back ( {buf + len, paddingLen} );
len += paddingLen;
totalLen += paddingLen;
}
macBuf = buf + len;
// allocate 16 bytes for MAC
len += 16;
}
bufs.push_back (boost::asio::buffer (buf, len));
}
if (!macBuf) // last block was not enough for MAC
{
// allocate send buffer
m_NextSendBuffer = new uint8_t[287]; // can be any size > 16, we just allocate 287 frequently
// create padding block
auto paddingLen = CreatePaddingBlock (totalLen, m_NextSendBuffer, 287 - 16);
// and padding block to encrypt and send
if (paddingLen)
encryptBufs.push_back ( {m_NextSendBuffer, paddingLen} );
bufs.push_back (boost::asio::buffer (m_NextSendBuffer, paddingLen + 16));
macBuf = m_NextSendBuffer + paddingLen;
totalLen += paddingLen;
}
uint8_t nonce[12];
CreateNonce (m_SendSequenceNumber, nonce); m_SendSequenceNumber++;
i2p::crypto::AEADChaCha20Poly1305Encrypt (encryptBufs, m_SendKey, nonce, macBuf); // encrypt buffers
SetNextSentFrameLength (totalLen + 16, first->GetNTCP2Header () - 5); // frame length right before first block
// send buffers
m_IsSending = true;