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decrypt Y for NTCP2

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pull/1194/head
orignal 6 years ago
parent 966256ac32
commit ee0ae0b74b
3 changed files with 30 additions and 18 deletions
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2
libi2pd/Crypto.h
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@ -181,6 +181,7 @@ namespace crypto
void SetKey (const AESKey& key) { m_ECBEncryption.SetKey (key); }; // 32 bytes
void SetIV (const uint8_t * iv) { memcpy ((uint8_t *)m_LastBlock, iv, 16); }; // 16 bytes
void GetIV (uint8_t * iv) const { memcpy (iv, (const uint8_t *)m_LastBlock, 16); };
void Encrypt (int numBlocks, const ChipherBlock * in, ChipherBlock * out);
void Encrypt (const uint8_t * in, std::size_t len, uint8_t * out);
@ -203,6 +204,7 @@ namespace crypto
void SetKey (const AESKey& key) { m_ECBDecryption.SetKey (key); }; // 32 bytes
void SetIV (const uint8_t * iv) { memcpy ((uint8_t *)m_IV, iv, 16); }; // 16 bytes
void GetIV (uint8_t * iv) const { memcpy (iv, (const uint8_t *)m_IV, 16); };
void Decrypt (int numBlocks, const ChipherBlock * in, ChipherBlock * out);
void Decrypt (const uint8_t * in, std::size_t len, uint8_t * out);

42
libi2pd/NTCP2.cpp
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@ -22,7 +22,7 @@ namespace transport
if (addr->ntcp2)
{
memcpy (m_RemoteStaticKey, addr->ntcp2->staticKey, 32);
memcpy (m_RemoteIV, addr->ntcp2->iv, 16);
memcpy (m_IV, addr->ntcp2->iv, 16);
}
else
LogPrint (eLogWarning, "NTCP2: Missing NTCP2 parameters");
@ -50,7 +50,7 @@ namespace transport
m_Server.GetService ().post (std::bind (&NTCP2Session::Terminate, shared_from_this ()));
}
bool NTCP2Session::KeyDerivationFunction1 (const uint8_t * rs, const uint8_t * pub, uint8_t * derived, uint8_t * ad)
bool NTCP2Session::KeyDerivationFunction1 (const uint8_t * rs, const uint8_t * pub, uint8_t * derived)
{
static const char protocolName[] = "Noise_XK_25519_ChaChaPoly_SHA256"; // 32 bytes
uint8_t h[64], ck[33];
@ -61,7 +61,7 @@ namespace transport
SHA256 (h, 64, h);
// h = SHA256(h || pub)
memcpy (h + 32, pub, 32);
SHA256 (h, 64, ad);
SHA256 (h, 64, m_H);
// x25519 between rs and priv
uint8_t inputKeyMaterial[32];
BN_CTX * ctx = BN_CTX_new ();
@ -101,24 +101,25 @@ namespace transport
// encrypt X
i2p::crypto::CBCEncryption encryption;
encryption.SetKey (GetRemoteIdentity ()->GetIdentHash ());
encryption.SetIV (m_RemoteIV);
encryption.SetIV (m_IV);
encryption.Encrypt (x, 32, m_SessionRequestBuffer);
encryption.GetIV (m_IV); // save IV for SessionCreated
// encryption key for next block
uint8_t key[32], ad[32];
KeyDerivationFunction1 (m_RemoteStaticKey, x, key, ad);
uint8_t key[32];
KeyDerivationFunction1 (m_RemoteStaticKey, x, key);
// fill options
uint8_t options[32]; // actual options size is 16 bytes
memset (options, 0, 16);
htobe16buf (options, 2); // ver
htobe16buf (options + 2, paddingLength); // padLen
htobe16buf (options + 4, 0); // m3p2Len TODO:
htobe16buf (options + 4, 550); // m3p2Len TODO:
// 2 bytes reserved
htobe32buf (options + 8, i2p::util::GetSecondsSinceEpoch ()); // tsA
// 4 bytes reserved
// sign and encrypt options
// sign and encrypt options, use m_H as AD
uint8_t nonce[12];
memset (nonce, 0, 12); // set nonce to zero
i2p::crypto::AEADChaCha20Poly1305Encrypt (options, 16, ad, 32, key, nonce, m_SessionRequestBuffer + 32, 32);
i2p::crypto::AEADChaCha20Poly1305Encrypt (options, 16, m_H, 32, key, nonce, m_SessionRequestBuffer + 32, 32);
// send message
boost::asio::async_write (m_Socket, boost::asio::buffer (m_SessionRequestBuffer, paddingLength + 64), boost::asio::transfer_all (),
std::bind(&NTCP2Session::HandleSessionRequestSent, shared_from_this (), std::placeholders::_1, std::placeholders::_2));
@ -127,28 +128,37 @@ namespace transport
void NTCP2Session::HandleSessionRequestSent (const boost::system::error_code& ecode, std::size_t bytes_transferred)
{
(void) bytes_transferred;
delete[] m_SessionRequestBuffer; m_SessionRequestBuffer = nullptr;
if (ecode)
{
LogPrint (eLogInfo, "NTCP2: couldn't send SessionRequest message: ", ecode.message ());
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 56 bytes (32 Y, and 24 ChaCha/Poly frame) first
boost::asio::async_read (m_Socket, boost::asio::buffer(m_SessionCreatedBuffer, sizeof (56)), boost::asio::transfer_all (),
boost::asio::async_read (m_Socket, boost::asio::buffer(m_SessionCreatedBuffer, 56), boost::asio::transfer_all (),
std::bind(&NTCP2Session::HandleSessionCreatedReceived, shared_from_this (), std::placeholders::_1, std::placeholders::_2));
}
}
void NTCP2Session::HandleSessionCreatedReceived (const boost::system::error_code& ecode, std::size_t bytes_transferred)
{
(void) bytes_transferred;
delete[] m_SessionCreatedBuffer; m_SessionCreatedBuffer = nullptr;
if (ecode)
LogPrint (eLogInfo, "NTCP2: SessionCreated read error: ", ecode.message ());
Terminate (); // TODO: continue
{
LogPrint (eLogWarning, "NTCP2: SessionCreated read error: ", ecode.message ());
Terminate ();
}
else
{
LogPrint (eLogWarning, "NTCP2: SessionCreated received ", bytes_transferred);
uint8_t y[32];
// decrypt Y
i2p::crypto::CBCDecryption decryption;
decryption.SetKey (GetRemoteIdentity ()->GetIdentHash ());
decryption.SetIV (m_IV);
decryption.Decrypt (m_SessionCreatedBuffer, 32, y);
}
}
void NTCP2Session::ClientLogin ()

4
libi2pd/NTCP2.h
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@ -29,7 +29,7 @@ namespace transport
private:
bool KeyDerivationFunction1 (const uint8_t * rs, const uint8_t * pub, uint8_t * derived, uint8_t * ad); // for SessionRequest
bool KeyDerivationFunction1 (const uint8_t * rs, const uint8_t * pub, uint8_t * derived); // for SessionRequest
void CreateEphemeralKey (uint8_t * pub);
void SendSessionRequest ();
@ -43,7 +43,7 @@ namespace transport
bool m_IsEstablished, m_IsTerminated;
uint8_t m_ExpandedPrivateKey[64]; // x25519 ephemeral key
uint8_t m_RemoteStaticKey[32], m_RemoteIV[16];
uint8_t m_RemoteStaticKey[32], m_IV[16], m_H[32];
uint8_t * m_SessionRequestBuffer, * m_SessionCreatedBuffer;
};

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