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I2P: End-to-End encrypted and anonymous Internet
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368 lines
12 KiB
368 lines
12 KiB
#include <openssl/rand.h> |
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#include <openssl/sha.h> |
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#include <openssl/hmac.h> |
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#include <stdlib.h> |
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#include <vector> |
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#include "Log.h" |
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#include "I2PEndian.h" |
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#include "Crypto.h" |
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#include "Ed25519.h" |
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#include "RouterContext.h" |
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#include "NTCP2.h" |
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namespace i2p |
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{ |
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namespace transport |
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{ |
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NTCP2Session::NTCP2Session (NTCP2Server& server, std::shared_ptr<const i2p::data::RouterInfo> in_RemoteRouter): |
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TransportSession (in_RemoteRouter, 30), |
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m_Server (server), m_Socket (m_Server.GetService ()), |
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m_IsEstablished (false), m_IsTerminated (false), |
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m_SessionRequestBuffer (nullptr), m_SessionCreatedBuffer (nullptr), m_SessionConfirmedBuffer (nullptr) |
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{ |
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auto addr = in_RemoteRouter->GetNTCPAddress (); |
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if (addr->ntcp2) |
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{ |
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memcpy (m_RemoteStaticKey, addr->ntcp2->staticKey, 32); |
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memcpy (m_IV, addr->ntcp2->iv, 16); |
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} |
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else |
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LogPrint (eLogWarning, "NTCP2: Missing NTCP2 parameters"); |
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} |
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NTCP2Session::~NTCP2Session () |
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{ |
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delete[] m_SessionRequestBuffer; |
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delete[] m_SessionCreatedBuffer; |
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delete[] m_SessionConfirmedBuffer; |
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} |
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void NTCP2Session::Terminate () |
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{ |
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if (!m_IsTerminated) |
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{ |
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m_IsTerminated = true; |
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m_IsEstablished = false; |
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m_Socket.close (); |
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LogPrint (eLogDebug, "NTCP2: session terminated"); |
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} |
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} |
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void NTCP2Session::Done () |
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{ |
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m_Server.GetService ().post (std::bind (&NTCP2Session::Terminate, shared_from_this ())); |
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} |
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void NTCP2Session::MixKey (const uint8_t * inputKeyMaterial, uint8_t * derived) |
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{ |
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// temp_key = HMAC-SHA256(ck, input_key_material) |
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uint8_t tempKey[32]; unsigned int len; |
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HMAC(EVP_sha256(), m_CK, 32, inputKeyMaterial, 32, tempKey, &len); |
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// ck = HMAC-SHA256(temp_key, byte(0x01)) |
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static uint8_t one[1] = { 1 }; |
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HMAC(EVP_sha256(), tempKey, 32, one, 1, m_CK, &len); |
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// derived = HMAC-SHA256(temp_key, ck || byte(0x02)) |
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m_CK[32] = 2; |
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HMAC(EVP_sha256(), tempKey, 32, m_CK, 33, derived, &len); |
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} |
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void NTCP2Session::KeyDerivationFunction1 (const uint8_t * rs, const uint8_t * pub, uint8_t * derived) |
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{ |
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static const char protocolName[] = "Noise_XK_25519_ChaChaPoly_SHA256"; // 32 bytes |
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uint8_t h[64]; |
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memcpy (m_CK, protocolName, 32); |
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SHA256 ((const uint8_t *)protocolName, 32, h); |
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// h = SHA256(h || rs) |
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memcpy (h + 32, rs, 32); |
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SHA256 (h, 64, h); |
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// h = SHA256(h || pub) |
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memcpy (h + 32, pub, 32); |
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SHA256 (h, 64, m_H); |
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// x25519 between rs and priv |
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uint8_t inputKeyMaterial[32]; |
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BN_CTX * ctx = BN_CTX_new (); |
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i2p::crypto::GetEd25519 ()->ScalarMul (rs, m_ExpandedPrivateKey, inputKeyMaterial, ctx); // rs*priv |
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BN_CTX_free (ctx); |
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MixKey (inputKeyMaterial, derived); |
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} |
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void NTCP2Session::KeyDerivationFunction2 (const uint8_t * pub, const uint8_t * sessionRequest, size_t sessionRequestLen, uint8_t * derived) |
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{ |
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uint8_t h[64]; |
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memcpy (h, m_H, 32); |
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memcpy (h + 32, sessionRequest + 32, 32); // encrypted payload |
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SHA256 (h, 64, h); |
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int paddingLength = sessionRequestLen - 64; |
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if (paddingLength > 0) |
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{ |
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std::vector<uint8_t> h1(paddingLength + 32); |
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memcpy (h1.data (), h, 32); |
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memcpy (h1.data () + 32, sessionRequest + 64, paddingLength); |
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SHA256 (h1.data (), paddingLength + 32, h); |
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} |
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memcpy (h + 32, pub, 32); |
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SHA256 (h, 64, m_H); |
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// x25519 between remote pub and priv |
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uint8_t inputKeyMaterial[32]; |
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BN_CTX * ctx = BN_CTX_new (); |
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i2p::crypto::GetEd25519 ()->ScalarMul (pub, m_ExpandedPrivateKey, inputKeyMaterial, ctx); |
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BN_CTX_free (ctx); |
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MixKey (inputKeyMaterial, derived); |
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} |
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void NTCP2Session::KeyDerivationFunction3 (const uint8_t * staticPrivKey, uint8_t * derived) |
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{ |
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uint8_t inputKeyMaterial[32]; |
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BN_CTX * ctx = BN_CTX_new (); |
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i2p::crypto::GetEd25519 ()->ScalarMul (m_Y, staticPrivKey, inputKeyMaterial, ctx); |
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BN_CTX_free (ctx); |
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MixKey (inputKeyMaterial, derived); |
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} |
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void NTCP2Session::CreateEphemeralKey (uint8_t * pub) |
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{ |
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uint8_t key[32]; |
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RAND_bytes (key, 32); |
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i2p::crypto::Ed25519::ExpandPrivateKey (key, m_ExpandedPrivateKey); |
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BN_CTX * ctx = BN_CTX_new (); |
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i2p::crypto::GetEd25519 ()->ScalarMulB (m_ExpandedPrivateKey, pub, ctx); |
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BN_CTX_free (ctx); |
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} |
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void NTCP2Session::SendSessionRequest () |
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{ |
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// create buffer and fill padding |
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auto paddingLength = rand () % (287 - 64); // message length doesn't exceed 287 bytes |
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m_SessionRequestBufferLen = paddingLength + 64; |
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m_SessionRequestBuffer = new uint8_t[m_SessionRequestBufferLen]; |
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RAND_bytes (m_SessionRequestBuffer + 64, paddingLength); |
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// generate key pair (X) |
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uint8_t x[32]; |
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CreateEphemeralKey (x); |
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// encrypt X |
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i2p::crypto::CBCEncryption encryption; |
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encryption.SetKey (GetRemoteIdentity ()->GetIdentHash ()); |
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encryption.SetIV (m_IV); |
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encryption.Encrypt (x, 32, m_SessionRequestBuffer); |
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encryption.GetIV (m_IV); // save IV for SessionCreated |
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// encryption key for next block |
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uint8_t key[32]; |
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KeyDerivationFunction1 (m_RemoteStaticKey, x, key); |
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// fill options |
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uint8_t options[32]; // actual options size is 16 bytes |
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memset (options, 0, 16); |
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htobe16buf (options, 2); // ver |
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htobe16buf (options + 2, paddingLength); // padLen |
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htobe16buf (options + 4, i2p::context.GetRouterInfo ().GetBufferLen () + 20); // m3p2Len (RI header + RI + MAC for now) TODO: implement options |
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// 2 bytes reserved |
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htobe32buf (options + 8, i2p::util::GetSecondsSinceEpoch ()); // tsA |
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// 4 bytes reserved |
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// sign and encrypt options, use m_H as AD |
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uint8_t nonce[12]; |
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memset (nonce, 0, 12); // set nonce to zero |
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i2p::crypto::AEADChaCha20Poly1305 (options, 16, m_H, 32, key, nonce, m_SessionRequestBuffer + 32, 32, true); // encrypt |
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// send message |
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boost::asio::async_write (m_Socket, boost::asio::buffer (m_SessionRequestBuffer, m_SessionRequestBufferLen), boost::asio::transfer_all (), |
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std::bind(&NTCP2Session::HandleSessionRequestSent, shared_from_this (), std::placeholders::_1, std::placeholders::_2)); |
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} |
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void NTCP2Session::HandleSessionRequestSent (const boost::system::error_code& ecode, std::size_t bytes_transferred) |
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{ |
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(void) bytes_transferred; |
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if (ecode) |
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{ |
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LogPrint (eLogWarning, "NTCP2: couldn't send SessionRequest message: ", ecode.message ()); |
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Terminate (); |
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} |
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else |
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{ |
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m_SessionCreatedBuffer = new uint8_t[287]; // TODO: determine actual max size |
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// we receive first 56 bytes (32 Y, and 24 ChaCha/Poly frame) first |
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boost::asio::async_read (m_Socket, boost::asio::buffer(m_SessionCreatedBuffer, 56), boost::asio::transfer_all (), |
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std::bind(&NTCP2Session::HandleSessionCreatedReceived, shared_from_this (), std::placeholders::_1, std::placeholders::_2)); |
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} |
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} |
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void NTCP2Session::HandleSessionCreatedReceived (const boost::system::error_code& ecode, std::size_t bytes_transferred) |
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{ |
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if (ecode) |
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{ |
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LogPrint (eLogWarning, "NTCP2: SessionCreated read error: ", ecode.message ()); |
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Terminate (); |
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} |
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else |
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{ |
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LogPrint (eLogDebug, "NTCP2: SessionCreated received ", bytes_transferred); |
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m_SessionCreatedBufferLen = 56; |
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// decrypt Y |
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i2p::crypto::CBCDecryption decryption; |
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decryption.SetKey (GetRemoteIdentity ()->GetIdentHash ()); |
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decryption.SetIV (m_IV); |
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decryption.Decrypt (m_SessionCreatedBuffer, 32, m_Y); |
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// decryption key for next block (m_K) |
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KeyDerivationFunction2 (m_Y, m_SessionRequestBuffer, m_SessionRequestBufferLen, m_K); |
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// decrypt and verify MAC |
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uint8_t payload[8]; |
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uint8_t nonce[12]; |
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memset (nonce, 0, 12); // set nonce to zero |
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if (i2p::crypto::AEADChaCha20Poly1305 (m_SessionCreatedBuffer + 32, 8, m_H, 32, m_K, nonce, payload, 8, false)) // decrypt |
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{ |
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uint16_t paddingLen = bufbe16toh(payload); |
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LogPrint (eLogDebug, "NTCP2: padding length ", paddingLen); |
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if (paddingLen > 0) |
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{ |
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boost::asio::async_read (m_Socket, boost::asio::buffer(m_SessionCreatedBuffer + 56, paddingLen), boost::asio::transfer_all (), |
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std::bind(&NTCP2Session::HandleSessionCreatedPaddingReceived, shared_from_this (), std::placeholders::_1, std::placeholders::_2)); |
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} |
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else |
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SendSessionConfirmed (); |
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} |
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else |
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{ |
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LogPrint (eLogWarning, "NTCP2: SessionCreated MAC verification failed "); |
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Terminate (); |
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} |
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} |
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} |
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void NTCP2Session::HandleSessionCreatedPaddingReceived (const boost::system::error_code& ecode, std::size_t bytes_transferred) |
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{ |
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if (ecode) |
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{ |
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LogPrint (eLogWarning, "NTCP2: SessionCreated padding read error: ", ecode.message ()); |
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Terminate (); |
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} |
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else |
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{ |
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m_SessionCreatedBufferLen += bytes_transferred; |
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SendSessionConfirmed (); |
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} |
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} |
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void NTCP2Session::SendSessionConfirmed () |
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{ |
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// update AD |
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uint8_t h[80]; |
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memcpy (h, m_H, 32); |
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memcpy (h + 32, m_SessionCreatedBuffer + 32, 24); // encrypted payload |
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SHA256 (h, 56, h); |
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int paddingLength = m_SessionCreatedBufferLen - 56; |
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if (paddingLength > 0) |
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{ |
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std::vector<uint8_t> h1(paddingLength + 32); |
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memcpy (h1.data (), h, 32); |
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memcpy (h1.data () + 32, m_SessionCreatedBuffer + 56, paddingLength); |
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SHA256 (h1.data (), paddingLength + 32, h); |
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} |
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// part1 48 bytes |
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m_SessionConfirmedBuffer = new uint8_t[2048]; // TODO: actual size |
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uint8_t nonce[12]; |
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memset (nonce, 0, 4); htole64buf (nonce + 4, 1); // set nonce to 1 |
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i2p::crypto::AEADChaCha20Poly1305 (i2p::context.GetNTCP2StaticPublicKey (), 32, h, 32, m_K, nonce, m_SessionConfirmedBuffer, 48, true); // encrypt |
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// part 2 |
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// update AD again |
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memcpy (h + 32, m_SessionConfirmedBuffer, 48); |
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SHA256 (h, 80, m_H); |
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size_t m3p2Len = i2p::context.GetRouterInfo ().GetBufferLen () + 20; |
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std::vector<uint8_t> buf(m3p2Len - 16); |
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buf[0] = 2; // block |
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htobe16buf (buf.data () + 1, i2p::context.GetRouterInfo ().GetBufferLen () + 1); // flag + RI |
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buf[3] = 0; // flag |
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memcpy (buf.data () + 4, i2p::context.GetRouterInfo ().GetBuffer (), i2p::context.GetRouterInfo ().GetBufferLen ()); |
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uint8_t key[32]; |
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KeyDerivationFunction3 (i2p::context.GetNTCP2StaticPrivateKey (), key); |
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memset (nonce, 0, 12); // set nonce to 0 again |
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i2p::crypto::AEADChaCha20Poly1305 (buf.data (), m3p2Len - 16, m_H, 32, key, nonce, m_SessionConfirmedBuffer + 48, m3p2Len, true); // encrypt |
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// send message |
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boost::asio::async_write (m_Socket, boost::asio::buffer (m_SessionConfirmedBuffer, m3p2Len + 48), boost::asio::transfer_all (), |
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std::bind(&NTCP2Session::HandleSessionConfirmedSent, shared_from_this (), std::placeholders::_1, std::placeholders::_2)); |
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} |
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void NTCP2Session::HandleSessionConfirmedSent (const boost::system::error_code& ecode, std::size_t bytes_transferred) |
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{ |
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LogPrint (eLogDebug, "NTCP2: SessionConfirmed sent"); |
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Terminate (); // TODO |
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} |
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void NTCP2Session::ClientLogin () |
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{ |
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SendSessionRequest (); |
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} |
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NTCP2Server::NTCP2Server (): |
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m_IsRunning (false), m_Thread (nullptr), m_Work (m_Service) |
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{ |
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} |
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NTCP2Server::~NTCP2Server () |
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{ |
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Stop (); |
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} |
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void NTCP2Server::Start () |
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{ |
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if (!m_IsRunning) |
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{ |
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m_IsRunning = true; |
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m_Thread = new std::thread (std::bind (&NTCP2Server::Run, this)); |
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} |
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} |
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void NTCP2Server::Stop () |
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{ |
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if (m_IsRunning) |
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{ |
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m_IsRunning = false; |
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m_Service.stop (); |
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if (m_Thread) |
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{ |
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m_Thread->join (); |
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delete m_Thread; |
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m_Thread = nullptr; |
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} |
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} |
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} |
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void NTCP2Server::Run () |
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{ |
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while (m_IsRunning) |
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{ |
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try |
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{ |
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m_Service.run (); |
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} |
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catch (std::exception& ex) |
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{ |
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LogPrint (eLogError, "NTCP2: runtime exception: ", ex.what ()); |
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} |
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} |
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} |
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void NTCP2Server::Connect(const boost::asio::ip::address & address, uint16_t port, std::shared_ptr<NTCP2Session> conn) |
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{ |
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LogPrint (eLogDebug, "NTCP2: Connecting to ", address ,":", port); |
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m_Service.post([this, address, port, conn]() |
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{ |
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conn->GetSocket ().async_connect (boost::asio::ip::tcp::endpoint (address, port), std::bind (&NTCP2Server::HandleConnect, this, std::placeholders::_1, conn)); |
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}); |
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} |
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void NTCP2Server::HandleConnect (const boost::system::error_code& ecode, std::shared_ptr<NTCP2Session> conn) |
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{ |
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if (ecode) |
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{ |
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LogPrint (eLogInfo, "NTCP2: Connect error ", ecode.message ()); |
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conn->Terminate (); |
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} |
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else |
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{ |
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LogPrint (eLogDebug, "NTCP2: Connected to ", conn->GetSocket ().remote_endpoint ()); |
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conn->ClientLogin (); |
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} |
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} |
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} |
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} |
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