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i2pd
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move handshake messages creation to NTCP2Establisher

pull/1221/head
orignal 6 years ago
parent
d320a89590
commit
5b83d4bef8
2 changed files with 104 additions and 86 deletions
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  1. 183
      libi2pd/NTCP2.cpp
  2. 7
      libi2pd/NTCP2.h

183
libi2pd/NTCP2.cpp
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@ -142,20 +142,108 @@ namespace transport @@ -142,20 +142,108 @@ namespace transport
i2p::crypto::GetEd25519 ()->ScalarMulB (m_EphemeralPrivateKey, m_EphemeralPublicKey, m_Ctx);
}
void NTCP2Establisher::CreateSessionRequestBuffer (size_t paddingLen)
void NTCP2Establisher::CreateSessionRequestMessage ()
{
m_SessionRequestBufferLen = paddingLen + 64;
// 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, paddingLen);
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[1] = 2; // ver
htobe16buf (options + 2, paddingLength); // padLen
m3p2Len = i2p::context.GetRouterInfo ().GetBufferLen () + 20; // (RI header + RI + MAC for now) TODO: implement options
htobe16buf (options + 4, 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_H, 32, m_K, nonce, m_SessionRequestBuffer + 32, 32, true); // encrypt
}
void NTCP2Establisher::CreateSessionCreatedBuffer (size_t paddingLen)
void NTCP2Establisher::CreateSessionCreatedMessage ()
{
auto paddingLen = rand () % (287 - 64);
m_SessionCreatedBufferLen = paddingLen + 64;
m_SessionCreatedBuffer = new uint8_t[m_SessionCreatedBufferLen];
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, m_H, 32, m_K, nonce, m_SessionCreatedBuffer + 32, 32, true); // encrypt
}
void NTCP2Establisher::CreateSessionConfirmedMessagePart1 (const uint8_t * nonce)
{
// update AD
SHA256_CTX ctx;
SHA256_Init (&ctx);
SHA256_Update (&ctx, m_H, 32);
SHA256_Update (&ctx, m_SessionCreatedBuffer + 32, 32); // encrypted payload
SHA256_Final (m_H, &ctx);
int paddingLength = m_SessionCreatedBufferLen - 64;
if (paddingLength > 0)
{
SHA256_CTX ctx1;
SHA256_Init (&ctx1);
SHA256_Update (&ctx1, m_H, 32);
SHA256_Update (&ctx1, m_SessionCreatedBuffer + 64, paddingLength);
SHA256_Final (m_H, &ctx1);
}
// part1 48 bytes
m_SessionConfirmedBuffer = new uint8_t[m3p2Len + 48];
i2p::crypto::AEADChaCha20Poly1305 (i2p::context.GetNTCP2StaticPublicKey (), 32, m_H, 32, m_K, nonce, m_SessionConfirmedBuffer, 48, true); // encrypt
}
void NTCP2Establisher::CreateSessionConfirmedMessagePart2 (const uint8_t * nonce)
{
// part 2
// update AD again
SHA256_CTX ctx;
SHA256_Init (&ctx);
SHA256_Update (&ctx, m_H, 32);
SHA256_Update (&ctx, m_SessionConfirmedBuffer, 48);
SHA256_Final (m_H, &ctx);
// fill and encrypt
uint8_t * buf = m_SessionConfirmedBuffer + 48;
buf[0] = eNTCP2BlkRouterInfo; // block
htobe16buf (buf + 1, i2p::context.GetRouterInfo ().GetBufferLen () + 1); // flag + RI
buf[3] = 0; // flag
memcpy (buf + 4, i2p::context.GetRouterInfo ().GetBuffer (), i2p::context.GetRouterInfo ().GetBufferLen ());
KDF3Alice ();
i2p::crypto::AEADChaCha20Poly1305 (buf, m3p2Len - 16, m_H, 32, m_K, nonce, buf, m3p2Len, true); // encrypt
// update h again
SHA256_Init (&ctx);
SHA256_Update (&ctx, m_H, 32);
SHA256_Update (&ctx, buf, m3p2Len);
SHA256_Final (m_H, &ctx); //h = SHA256(h || ciphertext)
}
NTCP2Session::NTCP2Session (NTCP2Server& server, std::shared_ptr<const i2p::data::RouterInfo> in_RemoteRouter):
TransportSession (in_RemoteRouter, NTCP2_ESTABLISH_TIMEOUT),
m_Server (server), m_Socket (m_Server.GetService ()),
@ -166,6 +254,7 @@ namespace transport @@ -166,6 +254,7 @@ namespace transport
m_Establisher.reset (new NTCP2Establisher);
if (in_RemoteRouter) // Alice
{
m_Establisher->m_RemoteIdentHash = GetRemoteIdentity ()->GetIdentHash ();
auto addr = in_RemoteRouter->GetNTCP2Address (true); // we need a published address
if (addr)
{
@ -246,31 +335,7 @@ namespace transport @@ -246,31 +335,7 @@ namespace transport
void NTCP2Session::SendSessionRequest ()
{
// create buffer and fill padding
auto paddingLength = rand () % (287 - 64); // message length doesn't exceed 287 bytes
m_Establisher->CreateSessionRequestBuffer (paddingLength);
// encrypt X
i2p::crypto::CBCEncryption encryption;
encryption.SetKey (GetRemoteIdentity ()->GetIdentHash ());
encryption.SetIV (m_Establisher->m_IV);
encryption.Encrypt (m_Establisher->GetPub (), 32, m_Establisher->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_Establisher->m_SessionRequestBuffer + 32, 32, true); // encrypt
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));
@ -365,23 +430,7 @@ namespace transport @@ -365,23 +430,7 @@ namespace transport
void NTCP2Session::SendSessionCreated ()
{
auto paddingLen = rand () % (287 - 64);
m_Establisher->CreateSessionCreatedBuffer (paddingLen);
// encrypt Y
i2p::crypto::CBCEncryption encryption;
encryption.SetKey (i2p::context.GetIdentHash ());
encryption.SetIV (m_Establisher->m_IV);
encryption.Encrypt (m_Establisher->GetPub (), 32, m_Establisher->m_SessionCreatedBuffer); // Y
// encryption key for next block (m_K)
m_Establisher->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, m_Establisher->GetH (), 32, m_Establisher->GetK (), nonce, m_Establisher->m_SessionCreatedBuffer + 32, 32, true); // encrypt
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));
@ -444,47 +493,13 @@ namespace transport @@ -444,47 +493,13 @@ namespace transport
}
}
void NTCP2Session::SendSessionConfirmed ()
{
// update AD
uint8_t h[80];
memcpy (h, m_Establisher->GetH (), 32);
memcpy (h + 32, m_Establisher->m_SessionCreatedBuffer + 32, 32); // encrypted payload
SHA256 (h, 64, h);
int paddingLength = m_Establisher->m_SessionCreatedBufferLen - 64;
if (paddingLength > 0)
{
SHA256_CTX ctx;
SHA256_Init (&ctx);
SHA256_Update (&ctx, h, 32);
SHA256_Update (&ctx, m_Establisher->m_SessionCreatedBuffer + 64, paddingLength);
SHA256_Final (h, &ctx);
}
// part1 48 bytes
m_Establisher->m_SessionConfirmedBuffer = new uint8_t[m_Establisher->m3p2Len + 48];
uint8_t nonce[12];
CreateNonce (1, nonce);
i2p::crypto::AEADChaCha20Poly1305 (i2p::context.GetNTCP2StaticPublicKey (), 32, h, 32, m_Establisher->GetK (), nonce, m_Establisher->m_SessionConfirmedBuffer, 48, true); // encrypt
// part 2
// update AD again
memcpy (h + 32, m_Establisher->m_SessionConfirmedBuffer, 48);
SHA256 (h, 80, m_Establisher->m_H);
std::vector<uint8_t> buf(m_Establisher->m3p2Len - 16); // -MAC
buf[0] = eNTCP2BlkRouterInfo; // 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_Establisher->m_SessionConfirmedBuffer + 48, m_Establisher->m3p2Len, true); // encrypt
uint8_t tmp[48];
memcpy (tmp, m_Establisher->m_SessionConfirmedBuffer, 48);
memcpy (m_Establisher->m_SessionConfirmedBuffer + 16, m_Establisher->GetH (), 32); // h || ciphertext
SHA256 (m_Establisher->m_SessionConfirmedBuffer + 16, m_Establisher->m3p2Len + 32, m_Establisher->m_H); //h = SHA256(h || ciphertext);
memcpy (m_Establisher->m_SessionConfirmedBuffer, tmp, 48);
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));

7
libi2pd/NTCP2.h
Unescape View File

@ -86,12 +86,15 @@ namespace transport @@ -86,12 +86,15 @@ namespace transport
void KeyDerivationFunction2 (const uint8_t * sessionRequest, size_t sessionRequestLen, const uint8_t * epub); // for SessionCreate
void CreateEphemeralKey ();
void CreateSessionRequestBuffer (size_t paddingLength);
void CreateSessionCreatedBuffer (size_t paddingLength);
void CreateSessionRequestMessage ();
void CreateSessionCreatedMessage ();
void CreateSessionConfirmedMessagePart1 (const uint8_t * nonce);
void CreateSessionConfirmedMessagePart2 (const uint8_t * nonce);
BN_CTX * m_Ctx;
uint8_t m_EphemeralPrivateKey[32], m_EphemeralPublicKey[32], m_RemoteEphemeralPublicKey[32]; // x25519
uint8_t m_RemoteStaticKey[32], m_IV[16], m_H[32] /*h*/, m_CK[33] /*ck*/, m_K[32] /*k*/;
i2p::data::IdentHash m_RemoteIdentHash;
uint16_t m3p2Len;
uint8_t * m_SessionRequestBuffer, * m_SessionCreatedBuffer, * m_SessionConfirmedBuffer;

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