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I2P: End-to-End encrypted and anonymous Internet https://i2pd.website/
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i2pd/libi2pd/NTCP2.cpp

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#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 "Ed25519.h"
#include "Siphash.h"
#include "RouterContext.h"
#include "Transports.h"
#include "NetDb.hpp"
#include "NTCP2.h"
namespace i2p
{
namespace transport
{
NTCP2Establisher::NTCP2Establisher ()
{
m_Ctx = BN_CTX_new ();
CreateEphemeralKey ();
}
NTCP2Establisher::~NTCP2Establisher ()
{
BN_CTX_free (m_Ctx);
}
void NTCP2Establisher::MixKey (const uint8_t * inputKeyMaterial, uint8_t * derived)
{
// temp_key = HMAC-SHA256(ck, input_key_material)
uint8_t tempKey[32]; unsigned int len;
HMAC(EVP_sha256(), m_CK, 32, inputKeyMaterial, 32, tempKey, &len);
// ck = HMAC-SHA256(temp_key, byte(0x01))
static uint8_t one[1] = { 1 };
HMAC(EVP_sha256(), tempKey, 32, one, 1, m_CK, &len);
// derived = HMAC-SHA256(temp_key, ck || byte(0x02))
m_CK[32] = 2;
HMAC(EVP_sha256(), tempKey, 32, m_CK, 33, derived, &len);
}
void NTCP2Establisher::KeyDerivationFunction1 (const uint8_t * pub, const uint8_t * priv, const uint8_t * rs, const uint8_t * epub)
{
static const uint8_t protocolNameHash[] =
{
0x72, 0xe8, 0x42, 0xc5, 0x45, 0xe1, 0x80, 0x80, 0xd3, 0x9c, 0x44, 0x93, 0xbb, 0x91, 0xd7, 0xed,
0xf2, 0x28, 0x98, 0x17, 0x71, 0x21, 0x8c, 0x1f, 0x62, 0x4e, 0x20, 0x6f, 0x28, 0xd3, 0x2f, 0x71
}; // SHA256 ("Noise_XKaesobfse+hs2+hs3_25519_ChaChaPoly_SHA256")
static const uint8_t hh[32] =
{
0x49, 0xff, 0x48, 0x3f, 0xc4, 0x04, 0xb9, 0xb2, 0x6b, 0x11, 0x94, 0x36, 0x72, 0xff, 0x05, 0xb5,
0x61, 0x27, 0x03, 0x31, 0xba, 0x89, 0xb8, 0xfc, 0x33, 0x15, 0x93, 0x87, 0x57, 0xdd, 0x3d, 0x1e
}; // SHA256 (protocolNameHash)
memcpy (m_CK, protocolNameHash, 32);
// h = SHA256(hh || rs)
SHA256_CTX ctx;
SHA256_Init (&ctx);
SHA256_Update (&ctx, hh, 32);
SHA256_Update (&ctx, rs, 32);
SHA256_Final (m_H, &ctx);
// h = SHA256(h || epub)
SHA256_Init (&ctx);
SHA256_Update (&ctx, m_H, 32);
SHA256_Update (&ctx, epub, 32);
SHA256_Final (m_H, &ctx);
// x25519 between rs and priv
uint8_t inputKeyMaterial[32];
i2p::crypto::GetEd25519 ()->ScalarMul (pub, priv, inputKeyMaterial, m_Ctx); // rs*priv
MixKey (inputKeyMaterial, m_K);
}
void NTCP2Establisher::KDF1Alice ()
{
KeyDerivationFunction1 (m_RemoteStaticKey, GetPriv (), m_RemoteStaticKey, GetPub ());
}
void NTCP2Establisher::KDF1Bob ()
{
KeyDerivationFunction1 (GetRemotePub (), i2p::context.GetNTCP2StaticPrivateKey (), i2p::context.GetNTCP2StaticPublicKey (), GetRemotePub ());
}
void NTCP2Establisher::KeyDerivationFunction2 (const uint8_t * sessionRequest, size_t sessionRequestLen, const uint8_t * epub)
{
SHA256_CTX ctx;
SHA256_Init (&ctx);
SHA256_Update (&ctx, m_H, 32);
SHA256_Update (&ctx, sessionRequest + 32, 32); // encrypted payload
SHA256_Final (m_H, &ctx);
int paddingLength = sessionRequestLen - 64;
if (paddingLength > 0)
{
SHA256_Init (&ctx);
SHA256_Update (&ctx, m_H, 32);
SHA256_Update (&ctx, sessionRequest + 64, paddingLength);
SHA256_Final (m_H, &ctx);
}
SHA256_Init (&ctx);
SHA256_Update (&ctx, m_H, 32);
SHA256_Update (&ctx, epub, 32);
SHA256_Final (m_H, &ctx);
// x25519 between remote pub and priv
uint8_t inputKeyMaterial[32];
i2p::crypto::GetEd25519 ()->ScalarMul (GetRemotePub (), GetPriv (), inputKeyMaterial, m_Ctx);
MixKey (inputKeyMaterial, m_K);
}
void NTCP2Establisher::KDF2Alice (const uint8_t * sessionRequest, size_t sessionRequestLen)
{
KeyDerivationFunction2 (sessionRequest, sessionRequestLen, GetRemotePub ());
}
void NTCP2Establisher::KDF2Bob (const uint8_t * sessionRequest, size_t sessionRequestLen)
{
KeyDerivationFunction2 (sessionRequest, sessionRequestLen, GetPub ());
}
void NTCP2Establisher::KDF3Alice ()
{
uint8_t inputKeyMaterial[32];
i2p::crypto::GetEd25519 ()->ScalarMul (GetRemotePub (), i2p::context.GetNTCP2StaticPrivateKey (), inputKeyMaterial, m_Ctx);
MixKey (inputKeyMaterial, m_K);
}
void NTCP2Establisher::KDF3Bob ()
{
uint8_t inputKeyMaterial[32];
i2p::crypto::GetEd25519 ()->ScalarMul (m_RemoteStaticKey, m_EphemeralPrivateKey, inputKeyMaterial, m_Ctx);
MixKey (inputKeyMaterial, m_K);
}
void NTCP2Establisher::CreateEphemeralKey ()
{
RAND_bytes (m_EphemeralPrivateKey, 32);
i2p::crypto::GetEd25519 ()->ScalarMulB (m_EphemeralPrivateKey, m_EphemeralPublicKey, m_Ctx);
}
NTCP2Session::NTCP2Session (NTCP2Server& server, std::shared_ptr<const i2p::data::RouterInfo> in_RemoteRouter):
TransportSession (in_RemoteRouter, 30),
m_Server (server), m_Socket (m_Server.GetService ()),
m_IsEstablished (false), m_IsTerminated (false),
m_SessionRequestBuffer (nullptr), m_SessionCreatedBuffer (nullptr), m_SessionConfirmedBuffer (nullptr),
m_NextReceivedBuffer (nullptr), m_NextSendBuffer (nullptr),
m_ReceiveSequenceNumber (0), m_SendSequenceNumber (0), m_IsSending (false)
{
m_Establisher.reset (new NTCP2Establisher);
if (in_RemoteRouter) // Alice
{
auto addr = in_RemoteRouter->GetNTCP2Address ();
if (addr->ntcp2)
{
memcpy (m_Establisher->m_RemoteStaticKey, addr->ntcp2->staticKey, 32);
memcpy (m_Establisher->m_IV, addr->ntcp2->iv, 16);
}
else
LogPrint (eLogWarning, "NTCP2: Missing NTCP2 parameters");
}
}
NTCP2Session::~NTCP2Session ()
{
delete[] m_SessionRequestBuffer;
delete[] m_SessionCreatedBuffer;
delete[] m_SessionConfirmedBuffer;
delete[] m_NextReceivedBuffer;
delete[] m_NextSendBuffer;
}
void NTCP2Session::Terminate ()
{
if (!m_IsTerminated)
{
m_IsTerminated = true;
m_IsEstablished = false;
m_Socket.close ();
transports.PeerDisconnected (shared_from_this ());
m_Server.RemoveNTCP2Session (shared_from_this ());
m_SendQueue.clear ();
LogPrint (eLogDebug, "NTCP2: session terminated");
}
}
void NTCP2Session::Done ()
{
m_Server.GetService ().post (std::bind (&NTCP2Session::Terminate, shared_from_this ()));
}
void NTCP2Session::Established ()
{
m_IsEstablished = true;
m_Establisher.reset (nullptr);
transports.PeerConnected (shared_from_this ());
}
void NTCP2Session::CreateNonce (uint64_t seqn, uint8_t * nonce)
{
memset (nonce, 0, 4);
htole64buf (nonce + 4, seqn);
}
void NTCP2Session::KeyDerivationFunctionDataPhase ()
{
uint8_t tempKey[32]; unsigned int len;
HMAC(EVP_sha256(), m_Establisher->GetCK (), 32, nullptr, 0, tempKey, &len); // temp_key = HMAC-SHA256(ck, zerolen)
static uint8_t one[1] = { 1 };
HMAC(EVP_sha256(), tempKey, 32, one, 1, m_Kab, &len); // k_ab = HMAC-SHA256(temp_key, byte(0x01)).
m_Kab[32] = 2;
HMAC(EVP_sha256(), tempKey, 32, m_Kab, 33, m_Kba, &len); // k_ba = HMAC-SHA256(temp_key, k_ab || byte(0x02))
static uint8_t ask[4] = { 'a', 's', 'k', 1 }, master[32];
HMAC(EVP_sha256(), tempKey, 32, ask, 4, master, &len); // ask_master = HMAC-SHA256(temp_key, "ask" || byte(0x01))
uint8_t h[39];
memcpy (h, m_Establisher->GetH (), 32);
memcpy (h + 32, "siphash", 7);
HMAC(EVP_sha256(), master, 32, h, 39, tempKey, &len); // temp_key = HMAC-SHA256(ask_master, h || "siphash")
HMAC(EVP_sha256(), tempKey, 32, one, 1, master, &len); // sip_master = HMAC-SHA256(temp_key, byte(0x01))
HMAC(EVP_sha256(), master, 32, nullptr, 0, tempKey, &len); // temp_key = HMAC-SHA256(sip_master, zerolen)
HMAC(EVP_sha256(), tempKey, 32, one, 1, m_Sipkeysab, &len); // sipkeys_ab = HMAC-SHA256(temp_key, byte(0x01)).
m_Sipkeysab[32] = 2;
HMAC(EVP_sha256(), tempKey, 32, m_Sipkeysab, 33, m_Sipkeysba, &len); // sipkeys_ba = HMAC-SHA256(temp_key, sipkeys_ab || byte(0x02))
}
void NTCP2Session::SendSessionRequest ()
{
// create buffer and fill padding
auto paddingLength = rand () % (287 - 64); // message length doesn't exceed 287 bytes
m_SessionRequestBufferLen = paddingLength + 64;
m_SessionRequestBuffer = new uint8_t[m_SessionRequestBufferLen];
RAND_bytes (m_SessionRequestBuffer + 64, paddingLength);
// encrypt X
i2p::crypto::CBCEncryption encryption;
encryption.SetKey (GetRemoteIdentity ()->GetIdentHash ());
encryption.SetIV (m_Establisher->m_IV);
encryption.Encrypt (m_Establisher->GetPub (), 32, m_SessionRequestBuffer); // X
encryption.GetIV (m_Establisher->m_IV); // save IV for SessionCreated
// encryption key for next block
m_Establisher->KDF1Alice ();
// fill options
uint8_t options[32]; // actual options size is 16 bytes
memset (options, 0, 16);
options[1] = 2; // ver
htobe16buf (options + 2, paddingLength); // padLen
m_Establisher->m3p2Len = i2p::context.GetRouterInfo ().GetBufferLen () + 20; // (RI header + RI + MAC for now) TODO: implement options
htobe16buf (options + 4, m_Establisher->m3p2Len);
// 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, m_Establisher->GetH (), 32, m_Establisher->GetK (), nonce, m_SessionRequestBuffer + 32, 32, true); // encrypt
// send message
boost::asio::async_write (m_Socket, boost::asio::buffer (m_SessionRequestBuffer, 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
{
m_SessionCreatedBuffer = new uint8_t[287]; // TODO: determine actual max size
// we receive first 64 bytes (32 Y, and 32 ChaCha/Poly frame) first
boost::asio::async_read (m_Socket, boost::asio::buffer(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
{
// decrypt X
i2p::crypto::CBCDecryption decryption;
decryption.SetKey (i2p::context.GetIdentHash ());
decryption.SetIV (i2p::context.GetNTCP2IV ());
decryption.Decrypt (m_SessionRequestBuffer, 32, m_Establisher->GetRemotePub ());
decryption.GetIV (m_Establisher->m_IV); // save IV for SessionCreated
// decryption key for next block
m_Establisher->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, m_Establisher->GetH (), 32, m_Establisher->GetK (), nonce, options, 16, false)) // decrypt
{
if (options[1] == 2)
{
uint16_t paddingLen = bufbe16toh (options + 2);
m_SessionRequestBufferLen = paddingLen + 64;
m_Establisher->m3p2Len = bufbe16toh (options + 4);
// TODO: check tsA
if (paddingLen > 0)
boost::asio::async_read (m_Socket, boost::asio::buffer(m_SessionRequestBuffer + 64, paddingLen), boost::asio::transfer_all (),
std::bind(&NTCP2Session::HandleSessionRequestPaddingReceived, shared_from_this (), std::placeholders::_1, std::placeholders::_2));
else
SendSessionCreated ();
}
else
{
LogPrint (eLogWarning, "NTCP2: SessionRequest version mismatch ", (int)options[1]);
Terminate ();
}
}
else
{
LogPrint (eLogWarning, "NTCP2: SessionRequest AEAD verification failed ");
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_SessionCreatedBuffer = new uint8_t[287]; // TODO: determine actual max size
// encrypt Y
i2p::crypto::CBCEncryption encryption;
encryption.SetKey (i2p::context.GetIdentHash ());
encryption.SetIV (m_Establisher->m_IV);
encryption.Encrypt (m_Establisher->GetPub (), 32, m_SessionCreatedBuffer); // Y
// encryption key for next block (m_K)
m_Establisher->KDF2Bob (m_SessionRequestBuffer, m_SessionRequestBufferLen);
auto paddingLen = rand () % (287 - 64);
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, m_Establisher->GetH (), 32, m_Establisher->GetK (), nonce, m_SessionCreatedBuffer + 32, 32, true); // encrypt
// fill padding
RAND_bytes (m_SessionCreatedBuffer + 64, paddingLen);
// send message
m_SessionCreatedBufferLen = paddingLen + 64;
boost::asio::async_write (m_Socket, boost::asio::buffer (m_SessionCreatedBuffer, 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);
m_SessionCreatedBufferLen = 64;
// decrypt Y
i2p::crypto::CBCDecryption decryption;
decryption.SetKey (GetRemoteIdentity ()->GetIdentHash ());
decryption.SetIV (m_Establisher->m_IV);
decryption.Decrypt (m_SessionCreatedBuffer, 32, m_Establisher->GetRemotePub ());
// decryption key for next block (m_K)
m_Establisher->KDF2Alice (m_SessionRequestBuffer, m_SessionRequestBufferLen);
// 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, m_Establisher->GetH (), 32, m_Establisher->GetK (), nonce, payload, 16, false)) // decrypt
{
uint16_t paddingLen = bufbe16toh(payload + 2);
LogPrint (eLogDebug, "NTCP2: padding length ", paddingLen);
// TODO: check tsB
if (paddingLen > 0)
{
boost::asio::async_read (m_Socket, boost::asio::buffer(m_SessionCreatedBuffer + 64, paddingLen), boost::asio::transfer_all (),
std::bind(&NTCP2Session::HandleSessionCreatedPaddingReceived, shared_from_this (), std::placeholders::_1, std::placeholders::_2));
}
else
SendSessionConfirmed ();
}
else
{
LogPrint (eLogWarning, "NTCP2: SessionCreated AEAD verification failed ");
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_SessionCreatedBufferLen += bytes_transferred;
SendSessionConfirmed ();
}
}
void NTCP2Session::SendSessionConfirmed ()
{
// update AD
uint8_t h[80];
memcpy (h, m_Establisher->GetH (), 32);
memcpy (h + 32, m_SessionCreatedBuffer + 32, 32); // encrypted payload
SHA256 (h, 64, h);
int paddingLength = m_SessionCreatedBufferLen - 64;
if (paddingLength > 0)
{
SHA256_CTX ctx;
SHA256_Init (&ctx);
SHA256_Update (&ctx, h, 32);
SHA256_Update (&ctx, m_SessionCreatedBuffer + 64, paddingLength);
SHA256_Final (h, &ctx);
}
// part1 48 bytes
m_SessionConfirmedBuffer = new uint8_t[2048]; // TODO: actual size
uint8_t nonce[12];
CreateNonce (1, nonce);
i2p::crypto::AEADChaCha20Poly1305 (i2p::context.GetNTCP2StaticPublicKey (), 32, h, 32, m_Establisher->GetK (), nonce, m_SessionConfirmedBuffer, 48, true); // encrypt
// part 2
// update AD again
memcpy (h + 32, m_SessionConfirmedBuffer, 48);
SHA256 (h, 80, m_Establisher->m_H);
std::vector<uint8_t> buf(m_Establisher->m3p2Len - 16); // -MAC
buf[0] = 2; // block
htobe16buf (buf.data () + 1, i2p::context.GetRouterInfo ().GetBufferLen () + 1); // flag + RI
buf[3] = 0; // flag
memcpy (buf.data () + 4, i2p::context.GetRouterInfo ().GetBuffer (), i2p::context.GetRouterInfo ().GetBufferLen ());
m_Establisher->KDF3Alice ();
memset (nonce, 0, 12); // set nonce to 0 again
i2p::crypto::AEADChaCha20Poly1305 (buf.data (), m_Establisher->m3p2Len - 16, m_Establisher->GetH (), 32, m_Establisher->GetK (), nonce, m_SessionConfirmedBuffer + 48, m_Establisher->m3p2Len, true); // encrypt
uint8_t tmp[48];
memcpy (tmp, m_SessionConfirmedBuffer, 48);
memcpy (m_SessionConfirmedBuffer + 16, m_Establisher->GetH (), 32); // h || ciphertext
SHA256 (m_SessionConfirmedBuffer + 16, m_Establisher->m3p2Len + 32, m_Establisher->m_H); //h = SHA256(h || ciphertext);
memcpy (m_SessionConfirmedBuffer, tmp, 48);
// send message
boost::asio::async_write (m_Socket, boost::asio::buffer (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)
{
LogPrint (eLogDebug, "NTCP2: SessionConfirmed sent");
KeyDerivationFunctionDataPhase ();
// Alice
m_SendKey = m_Kab;
m_ReceiveKey = m_Kba;
m_SendSipKey = m_Sipkeysab;
m_ReceiveSipKey = m_Sipkeysba;
memcpy (m_ReceiveIV, m_Sipkeysba + 16, 8);
memcpy (m_SendIV, 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_SessionConfirmedBuffer = new uint8_t[m_Establisher->m3p2Len + 48];
boost::asio::async_read (m_Socket, boost::asio::buffer(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 Part1 read error: ", ecode.message ());
Terminate ();
}
else
{
LogPrint (eLogDebug, "NTCP2: SessionConfirmed Part1 received");
// update AD
uint8_t h[80];
memcpy (h, m_Establisher->GetH (), 32);
memcpy (h + 32, m_SessionCreatedBuffer + 32, 32); // encrypted payload
SHA256 (h, 64, h);
int paddingLength = m_SessionCreatedBufferLen - 64;
if (paddingLength > 0)
{
SHA256_CTX ctx;
SHA256_Init (&ctx);
SHA256_Update (&ctx, h, 32);
SHA256_Update (&ctx, m_SessionCreatedBuffer + 64, paddingLength);
SHA256_Final (h, &ctx);
}
// part 1
uint8_t nonce[12];
CreateNonce (1, nonce);
if (i2p::crypto::AEADChaCha20Poly1305 (m_SessionConfirmedBuffer, 32, h, 32, m_Establisher->GetK (), nonce, m_Establisher->m_RemoteStaticKey, 32, false)) // decrypt S
{
// part 2
// update AD again
memcpy (h + 32, m_SessionConfirmedBuffer, 48);
SHA256 (h, 80, m_Establisher->m_H);
std::vector<uint8_t> buf(m_Establisher->m3p2Len - 16); // -MAC
m_Establisher->KDF3Bob ();
memset (nonce, 0, 12); // set nonce to 0 again
if (i2p::crypto::AEADChaCha20Poly1305 (m_SessionConfirmedBuffer + 48, m_Establisher->m3p2Len - 16, m_Establisher->GetH (), 32, m_Establisher->GetK (), nonce, buf.data (), m_Establisher->m3p2Len - 16, false)) // decrypt
{
// process RI
if (buf[0] == eNTCP2BlkRouterInfo)
{
auto size = bufbe16toh (buf.data () + 1);
if (size <= buf.size () - 3)
{
// TODO: check flag
i2p::data::netdb.AddRouterInfo (buf.data () + 4, size - 1); // 1 byte block type + 2 bytes size + 1 byte flag
// TODO: process options
}
else
LogPrint (eLogError, "NTCP2: Unexpected RouterInfo size ", size, " in SessionConfirmed");
}
else
LogPrint (eLogWarning, "NTCP2: unexpected block ", (int)buf[0], " in SessionConfirmed");
// caclulate new h again for KDF data
memcpy (m_SessionConfirmedBuffer + 16, m_Establisher->GetH (), 32); // h || ciphertext
SHA256 (m_SessionConfirmedBuffer + 16, m_Establisher->m3p2Len + 32, m_Establisher->m_H); //h = SHA256(h || ciphertext);
KeyDerivationFunctionDataPhase ();
// Bob
m_SendKey = m_Kba;
m_ReceiveKey = m_Kab;
m_SendSipKey = m_Sipkeysba;
m_ReceiveSipKey = m_Sipkeysab;
memcpy (m_ReceiveIV, m_Sipkeysab + 16, 8);
memcpy (m_SendIV, m_Sipkeysba + 16, 8);
Established ();
ReceiveLength ();
}
else
{
LogPrint (eLogWarning, "NTCP2: SessionConfirmed Part2 AEAD verification failed ");
Terminate ();
}
}
else
{
LogPrint (eLogWarning, "NTCP2: SessionConfirmed Part1 AEAD verification failed ");
Terminate ();
}
}
}
void NTCP2Session::ClientLogin ()
{
SendSessionRequest ();
}
void NTCP2Session::ServerLogin ()
{
m_SessionRequestBuffer = new uint8_t[287]; // 287 bytes max for now
boost::asio::async_read (m_Socket, boost::asio::buffer(m_SessionRequestBuffer, 64), boost::asio::transfer_all (),
std::bind(&NTCP2Session::HandleSessionRequestReceived, shared_from_this (),
std::placeholders::_1, std::placeholders::_2));
}
void NTCP2Session::ReceiveLength ()
{
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)
{
LogPrint (eLogWarning, "NTCP2: receive length read error: ", ecode.message ());
Terminate ();
}
else
{
i2p::crypto::Siphash<8> (m_ReceiveIV, m_ReceiveIV, 8, m_ReceiveSipKey);
m_NextReceivedLen = be16toh (m_NextReceivedLen ^ bufbe16toh(m_ReceiveIV));
LogPrint (eLogDebug, "NTCP2: received length ", m_NextReceivedLen);
delete[] m_NextReceivedBuffer;
m_NextReceivedBuffer = new uint8_t[m_NextReceivedLen];
Receive ();
}
}
void NTCP2Session::Receive ()
{
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)
{
LogPrint (eLogWarning, "NTCP2: receive read error: ", ecode.message ());
Terminate ();
}
else
{
m_NumReceivedBytes += bytes_transferred + 2; // + length
i2p::transport::transports.UpdateReceivedBytes (bytes_transferred);
uint8_t nonce[12];
CreateNonce (m_ReceiveSequenceNumber, nonce); m_ReceiveSequenceNumber++;
uint8_t * decrypted = new uint8_t[m_NextReceivedLen];
if (i2p::crypto::AEADChaCha20Poly1305 (m_NextReceivedBuffer, m_NextReceivedLen-16, nullptr, 0, m_ReceiveKey, nonce, decrypted, m_NextReceivedLen, false))
{
LogPrint (eLogDebug, "NTCP2: received message decrypted");
ProcessNextFrame (decrypted, m_NextReceivedLen-16);
ReceiveLength ();
}
else
{
LogPrint (eLogWarning, "NTCP2: Received MAC verification failed ");
Terminate ();
}
delete[] decrypted;
}
}
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.AddRouterInfo (frame + offset + 1, size - 1);
break;
}
case eNTCP2BlkI2NPMessage:
{
LogPrint (eLogDebug, "NTCP2: I2NP");
auto nextMsg = NewI2NPMessage (size);
nextMsg->len = nextMsg->offset + size + 7; // 7 more bytes for full I2NP header
memcpy (nextMsg->GetNTCP2Header (), frame + offset, size);
nextMsg->FromNTCP2 ();
m_Handler.PutNextMessage (nextMsg);
break;
}
case eNTCP2BlkTermination:
LogPrint (eLogDebug, "NTCP2: termination");
break;
case eNTCP2BlkPadding:
LogPrint (eLogDebug, "NTCP2: padding");
break;
default:
LogPrint (eLogWarning, "NTCP2: Unknown block type ", (int)blk);
}
offset += size;
}
m_Handler.Flush ();
}
void NTCP2Session::SendNextFrame (const uint8_t * payload, size_t len)
{
uint8_t nonce[12];
CreateNonce (m_SendSequenceNumber, nonce); m_SendSequenceNumber++;
m_NextSendBuffer = new uint8_t[len + 16 + 2];
i2p::crypto::AEADChaCha20Poly1305 (payload, len, nullptr, 0, m_SendKey, nonce, m_NextSendBuffer + 2, len + 16, true);
i2p::crypto::Siphash<8> (m_SendIV, m_SendIV, 8, m_SendSipKey);
htobuf16 (m_NextSendBuffer, bufbe16toh (m_SendIV) ^ htobe16(len + 16));
LogPrint (eLogDebug, "NTCP2: sent length ", len + 16);
// send message
m_IsSending = true;
boost::asio::async_write (m_Socket, boost::asio::buffer (m_NextSendBuffer, len + 16 + 2), boost::asio::transfer_all (),
std::bind(&NTCP2Session::HandleNextFrameSent, shared_from_this (), std::placeholders::_1, std::placeholders::_2));
}
void NTCP2Session::HandleNextFrameSent (const boost::system::error_code& ecode, std::size_t bytes_transferred)
{
m_NumSentBytes += bytes_transferred;
i2p::transport::transports.UpdateSentBytes (bytes_transferred);
delete[] m_NextSendBuffer; m_NextSendBuffer = nullptr;
LogPrint (eLogDebug, "NTCP2: Next frame sent");
m_IsSending = false;
SendQueue ();
}
void NTCP2Session::SendQueue ()
{
if (!m_SendQueue.empty ())
{
uint8_t * payload = new uint8_t[NTCP2_UNENCRYPTED_FRAME_MAX_SIZE];
size_t s = 0;
// add I2NP blocks
while (!m_SendQueue.empty ())
{
auto msg = m_SendQueue.front ();
size_t len = msg->GetNTCP2Length ();
if (s + len + 3 <= NTCP2_UNENCRYPTED_FRAME_MAX_SIZE) // 3 bytes block header
{
payload[s] = eNTCP2BlkI2NPMessage; // blk
htobe16buf (payload + s + 1, len); // size
s += 3;
msg->ToNTCP2 ();
memcpy (payload + s, msg->GetNTCP2Header (), len);
s += len;
m_SendQueue.pop_front ();
}
else
break;
}
// add padding block
int paddingSize = (s*NTCP2_MAX_PADDING_RATIO)/100;
if (s + paddingSize + 3 > NTCP2_UNENCRYPTED_FRAME_MAX_SIZE) paddingSize = NTCP2_UNENCRYPTED_FRAME_MAX_SIZE - s -3;
if (paddingSize) paddingSize = rand () % paddingSize;
payload[s] = eNTCP2BlkPadding; // blk
htobe16buf (payload + s + 1, paddingSize); // size
s += 3;
RAND_bytes (payload + s, paddingSize);
s += paddingSize;
// send
SendNextFrame (payload, s);
delete[] payload;
}
}
void NTCP2Session::SendI2NPMessages (const std::vector<std::shared_ptr<I2NPMessage> >& msgs)
{
m_Server.GetService ().post (std::bind (&NTCP2Session::PostI2NPMessages, shared_from_this (), msgs));
}
void NTCP2Session::PostI2NPMessages (std::vector<std::shared_ptr<I2NPMessage> > msgs)
{
if (m_IsTerminated) return;
for (auto it: msgs)
m_SendQueue.push_back (it);
if (!m_IsSending)
SendQueue ();
}
NTCP2Server::NTCP2Server ():
m_IsRunning (false), m_Thread (nullptr), m_Work (m_Service)
{
}
NTCP2Server::~NTCP2Server ()
{
Stop ();
}
void NTCP2Server::Start ()
{
if (!m_IsRunning)
{
m_IsRunning = true;
m_Thread = new std::thread (std::bind (&NTCP2Server::Run, this));
auto& addresses = context.GetRouterInfo ().GetAddresses ();
for (const auto& address: addresses)
{
if (!address) continue;
if (address->IsPublishedNTCP2 ())
{
if (address->host.is_v4())
{
try
{
m_NTCP2Acceptor.reset (new boost::asio::ip::tcp::acceptor (m_Service, boost::asio::ip::tcp::endpoint(boost::asio::ip::tcp::v4(), address->port)));
}
catch ( std::exception & ex )
{
LogPrint(eLogError, "NTCP2: Failed to bind to ip4 port ",address->port, ex.what());
continue;
}
LogPrint (eLogInfo, "NTCP2: Start listening TCP port ", address->port);
auto conn = std::make_shared<NTCP2Session>(*this);
m_NTCP2Acceptor->async_accept(conn->GetSocket (), std::bind (&NTCP2Server::HandleAccept, this, conn, std::placeholders::_1));
}
else if (address->host.is_v6() && context.SupportsV6 ())
{
m_NTCP2V6Acceptor.reset (new boost::asio::ip::tcp::acceptor (m_Service));
try
{
m_NTCP2V6Acceptor->open (boost::asio::ip::tcp::v6());
m_NTCP2V6Acceptor->set_option (boost::asio::ip::v6_only (true));
m_NTCP2V6Acceptor->bind (boost::asio::ip::tcp::endpoint(boost::asio::ip::tcp::v6(), address->port));
m_NTCP2V6Acceptor->listen ();
LogPrint (eLogInfo, "NTCP2: Start listening V6 TCP port ", address->port);
auto conn = std::make_shared<NTCP2Session> (*this);
m_NTCP2V6Acceptor->async_accept(conn->GetSocket (), std::bind (&NTCP2Server::HandleAcceptV6, this, conn, std::placeholders::_1));
} catch ( std::exception & ex ) {
LogPrint(eLogError, "NTCP: failed to bind to ip6 port ", address->port);
continue;
}
}
}
}
}
}
void NTCP2Server::Stop ()
{
{
// we have to copy it because Terminate changes m_NTCP2Sessions
auto ntcpSessions = m_NTCP2Sessions;
for (auto& it: ntcpSessions)
it.second->Terminate ();
for (auto& it: m_PendingIncomingSessions)
it->Terminate ();
}
m_NTCP2Sessions.clear ();
if (m_IsRunning)
{
m_IsRunning = false;
m_Service.stop ();
if (m_Thread)
{
m_Thread->join ();
delete m_Thread;
m_Thread = nullptr;
}
}
}
void NTCP2Server::Run ()
{
while (m_IsRunning)
{
try
{
m_Service.run ();
}
catch (std::exception& ex)
{
LogPrint (eLogError, "NTCP2: runtime exception: ", ex.what ());
}
}
}
bool NTCP2Server::AddNTCP2Session (std::shared_ptr<NTCP2Session> session)
{
if (!session || !session->GetRemoteIdentity ()) return false;
auto& ident = session->GetRemoteIdentity ()->GetIdentHash ();
auto it = m_NTCP2Sessions.find (ident);
if (it != m_NTCP2Sessions.end ())
{
LogPrint (eLogWarning, "NTCP2: session to ", ident.ToBase64 (), " already exists");
session->Terminate();
return false;
}
m_NTCP2Sessions.insert (std::make_pair (ident, session));
return true;
}
void NTCP2Server::RemoveNTCP2Session (std::shared_ptr<NTCP2Session> session)
{
if (session && session->GetRemoteIdentity ())
m_NTCP2Sessions.erase (session->GetRemoteIdentity ()->GetIdentHash ());
}
std::shared_ptr<NTCP2Session> NTCP2Server::FindNTCP2Session (const i2p::data::IdentHash& ident)
{
auto it = m_NTCP2Sessions.find (ident);
if (it != m_NTCP2Sessions.end ())
return it->second;
return nullptr;
}
void NTCP2Server::Connect(const boost::asio::ip::address & address, uint16_t port, std::shared_ptr<NTCP2Session> conn)
{
LogPrint (eLogDebug, "NTCP2: Connecting to ", address ,":", port);
m_Service.post([this, address, port, conn]()
{
if (this->AddNTCP2Session (conn))
{
conn->GetSocket ().async_connect (boost::asio::ip::tcp::endpoint (address, port), std::bind (&NTCP2Server::HandleConnect, this, std::placeholders::_1, conn));
}
});
}
void NTCP2Server::HandleConnect (const boost::system::error_code& ecode, std::shared_ptr<NTCP2Session> conn)
{
if (ecode)
{
LogPrint (eLogInfo, "NTCP2: Connect error ", ecode.message ());
conn->Terminate ();
}
else
{
LogPrint (eLogDebug, "NTCP2: Connected to ", conn->GetSocket ().remote_endpoint ());
conn->ClientLogin ();
}
}
void NTCP2Server::HandleAccept (std::shared_ptr<NTCP2Session> conn, const boost::system::error_code& error)
{
if (!error)
{
boost::system::error_code ec;
auto ep = conn->GetSocket ().remote_endpoint(ec);
if (!ec)
{
LogPrint (eLogDebug, "NTCP2: Connected from ", ep);
if (conn)
{
conn->ServerLogin ();
// m_PendingIncomingSessions.push_back (conn);
}
}
else
LogPrint (eLogError, "NTCP2: Connected from error ", ec.message ());
}
if (error != boost::asio::error::operation_aborted)
{
conn = std::make_shared<NTCP2Session> (*this);
m_NTCP2Acceptor->async_accept(conn->GetSocket (), std::bind (&NTCP2Server::HandleAccept, this,
conn, std::placeholders::_1));
}
}
void NTCP2Server::HandleAcceptV6 (std::shared_ptr<NTCP2Session> conn, const boost::system::error_code& error)
{
if (!error)
{
boost::system::error_code ec;
auto ep = conn->GetSocket ().remote_endpoint(ec);
if (!ec)
{
LogPrint (eLogDebug, "NTCP2: Connected from ", ep);
if (conn)
{
conn->ServerLogin ();
// m_PendingIncomingSessions.push_back (conn);
}
}
else
LogPrint (eLogError, "NTCP2: Connected from error ", ec.message ());
}
if (error != boost::asio::error::operation_aborted)
{
conn = std::make_shared<NTCP2Session> (*this);
m_NTCP2V6Acceptor->async_accept(conn->GetSocket (), std::bind (&NTCP2Server::HandleAcceptV6, this,
conn, std::placeholders::_1));
}
}
}
}