mirror of
https://github.com/PurpleI2P/i2pd
synced 2024-11-10 08:00:38 +03:00
414 lines
13 KiB
C++
414 lines
13 KiB
C++
#include <string.h>
|
|
#include <boost/bind.hpp>
|
|
#include <cryptopp/dh.h>
|
|
#include <cryptopp/secblock.h>
|
|
#include "CryptoConst.h"
|
|
#include "Log.h"
|
|
#include "Timestamp.h"
|
|
#include "RouterContext.h"
|
|
#include "hmac.h"
|
|
#include "SSU.h"
|
|
|
|
namespace i2p
|
|
{
|
|
namespace ssu
|
|
{
|
|
|
|
SSUSession::SSUSession (SSUServer * server, const boost::asio::ip::udp::endpoint& remoteEndpoint,
|
|
i2p::data::RouterInfo * router): m_Server (server), m_RemoteEndpoint (remoteEndpoint),
|
|
m_RemoteRouter (router), m_State (eSessionStateUnknown)
|
|
{
|
|
}
|
|
|
|
void SSUSession::CreateAESandMacKey (uint8_t * pubKey, uint8_t * aesKey, uint8_t * macKey)
|
|
{
|
|
CryptoPP::DH dh (i2p::crypto::elgp, i2p::crypto::elgg);
|
|
CryptoPP::SecByteBlock secretKey(dh.AgreedValueLength());
|
|
if (!dh.Agree (secretKey, i2p::context.GetPrivateKey (), pubKey))
|
|
{
|
|
LogPrint ("Couldn't create shared key");
|
|
return;
|
|
};
|
|
|
|
if (secretKey[0] & 0x80)
|
|
{
|
|
aesKey[0] = 0;
|
|
memcpy (aesKey + 1, secretKey, 31);
|
|
memcpy (macKey, secretKey + 31, 32);
|
|
}
|
|
else
|
|
{
|
|
memcpy (aesKey, secretKey, 32);
|
|
memcpy (macKey, secretKey + 32, 32);
|
|
}
|
|
}
|
|
|
|
void SSUSession::ProcessNextMessage (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& senderEndpoint)
|
|
{
|
|
switch (m_State)
|
|
{
|
|
case eSessionStateUnknown:
|
|
// session request
|
|
ProcessSessionRequest (buf, len, senderEndpoint);
|
|
break;
|
|
case eSessionStateRequestSent:
|
|
// session created
|
|
ProcessSessionCreated (buf, len);
|
|
break;
|
|
case eSessionStateCreatedSent:
|
|
// session confirmed
|
|
ProcessSessionConfirmed (buf, len);
|
|
break;
|
|
default:
|
|
LogPrint ("SSU state not implemented yet");
|
|
}
|
|
}
|
|
|
|
void SSUSession::ProcessSessionRequest (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& senderEndpoint)
|
|
{
|
|
LogPrint ("Process session request");
|
|
// use our intro key
|
|
if (ProcessIntroKeyEncryptedMessage (PAYLOAD_TYPE_SESSION_REQUEST,
|
|
i2p::context.GetRouterInfo (), buf, len))
|
|
{
|
|
m_State = eSessionStateRequestReceived;
|
|
LogPrint ("Session request received");
|
|
m_RemoteEndpoint = senderEndpoint;
|
|
SendSessionCreated (buf + sizeof (SSUHeader));
|
|
}
|
|
}
|
|
|
|
void SSUSession::ProcessSessionCreated (uint8_t * buf, size_t len)
|
|
{
|
|
LogPrint ("Process session created");
|
|
if (!m_RemoteRouter)
|
|
{
|
|
LogPrint ("Unsolicited session created message");
|
|
return;
|
|
}
|
|
|
|
// use remote intro key
|
|
if (ProcessIntroKeyEncryptedMessage (PAYLOAD_TYPE_SESSION_CREATED, *m_RemoteRouter, buf, len))
|
|
{
|
|
m_State = eSessionStateCreatedReceived;
|
|
LogPrint ("Session created received");
|
|
uint8_t * ourAddress = buf + sizeof (SSUHeader) + 257;
|
|
boost::asio::ip::address_v4 ourIP (be32toh (*(uint32_t* )(ourAddress)));
|
|
uint16_t ourPort = be16toh (*(uint16_t *)(ourAddress + 4));
|
|
LogPrint ("Our external address is ", ourIP.to_string (), ":", ourPort);
|
|
uint32_t relayTag = be32toh (*(uint32_t *)(buf + sizeof (SSUHeader) + 263));
|
|
SendSessionConfirmed (buf + sizeof (SSUHeader), ourAddress, relayTag);
|
|
}
|
|
}
|
|
|
|
void SSUSession::ProcessSessionConfirmed (uint8_t * buf, size_t len)
|
|
{
|
|
LogPrint ("Process session confirmed");
|
|
if (Validate (buf, len, m_MacKey))
|
|
{
|
|
Decrypt (buf, len, m_SessionKey);
|
|
SSUHeader * header = (SSUHeader *)buf;
|
|
if ((header->flag >> 4) == PAYLOAD_TYPE_SESSION_CONFIRMED)
|
|
{
|
|
m_State = eSessionStateConfirmedReceived;
|
|
LogPrint ("Session confirmed received");
|
|
// TODO:
|
|
}
|
|
else
|
|
LogPrint ("Unexpected payload type ", (int)(header->flag >> 4));
|
|
}
|
|
else
|
|
LogPrint ("MAC verifcation failed");
|
|
}
|
|
|
|
void SSUSession::SendSessionRequest ()
|
|
{
|
|
auto address = m_RemoteRouter ? m_RemoteRouter->GetSSUAddress () : nullptr;
|
|
if (!address)
|
|
{
|
|
LogPrint ("Missing remote SSU address");
|
|
return;
|
|
}
|
|
|
|
uint8_t buf[304 + 18]; // 304 bytes for ipv4 (320 for ipv6)
|
|
uint8_t * payload = buf + sizeof (SSUHeader);
|
|
memcpy (payload, i2p::context.GetRouterIdentity ().publicKey, 256);
|
|
payload[256] = 4; // we assume ipv4
|
|
*(uint32_t *)(payload + 257) = htobe32 (address->host.to_v4 ().to_ulong ());
|
|
|
|
uint8_t iv[16];
|
|
CryptoPP::RandomNumberGenerator& rnd = i2p::context.GetRandomNumberGenerator ();
|
|
rnd.GenerateBlock (iv, 16); // random iv
|
|
FillHeaderAndEncrypt (PAYLOAD_TYPE_SESSION_REQUEST, buf, 304, address->key, iv, address->key);
|
|
|
|
m_State = eSessionStateRequestSent;
|
|
m_Server->Send (buf, 304, m_RemoteEndpoint);
|
|
}
|
|
|
|
void SSUSession::SendSessionCreated (const uint8_t * x)
|
|
{
|
|
auto address = m_RemoteRouter ? m_RemoteRouter->GetSSUAddress () : nullptr;
|
|
if (!address)
|
|
{
|
|
LogPrint ("Missing remote SSU address");
|
|
return;
|
|
}
|
|
uint8_t signedData[532]; // x,y, remote IP, remote port, our IP, our port, relayTag, signed on time
|
|
memcpy (signedData, x, 256); // x
|
|
|
|
uint8_t buf[368 + 18];
|
|
uint8_t * payload = buf + sizeof (SSUHeader);
|
|
memcpy (payload, i2p::context.GetRouterIdentity ().publicKey, 256);
|
|
memcpy (signedData + 256, payload, 256); // y
|
|
payload += 256;
|
|
*payload = 4; // we assume ipv4
|
|
payload++;
|
|
*(uint32_t *)(payload) = htobe32 (m_RemoteEndpoint.address ().to_v4 ().to_ulong ());
|
|
payload += 4;
|
|
*(uint16_t *)(payload) = htobe16 (m_RemoteEndpoint.port ());
|
|
payload += 2;
|
|
memcpy (signedData + 512, payload - 6, 6); // remote endpoint IP and port
|
|
*(uint32_t *)(signedData + 518) = htobe32 (m_Server->GetEndpoint ().address ().to_v4 ().to_ulong ()); // our IP
|
|
*(uint16_t *)(signedData + 522) = htobe16 (m_Server->GetEndpoint ().port ()); // our port
|
|
*(uint32_t *)(payload) = 0; // relay tag, always 0 for now
|
|
payload += 4;
|
|
*(uint32_t *)(payload) = htobe32 (i2p::util::GetSecondsSinceEpoch ()); // signed on time
|
|
payload += 4;
|
|
memcpy (signedData + 524, payload - 8, 8); // relayTag and signed on time
|
|
i2p::context.Sign (signedData, 532, payload); // DSA signature
|
|
// TODO: fill padding with random data
|
|
|
|
uint8_t iv[16];
|
|
CryptoPP::RandomNumberGenerator& rnd = i2p::context.GetRandomNumberGenerator ();
|
|
rnd.GenerateBlock (iv, 16); // random iv
|
|
// encrypt signature and 8 bytes padding with newly created session key
|
|
m_Encryption.SetKeyWithIV (m_SessionKey, 32, iv);
|
|
m_Encryption.ProcessData (payload, payload, 48);
|
|
|
|
// encrypt message with intro key
|
|
FillHeaderAndEncrypt (PAYLOAD_TYPE_SESSION_CREATED, buf, 368, address->key, iv, address->key);
|
|
m_State = eSessionStateRequestSent;
|
|
m_Server->Send (buf, 368, m_RemoteEndpoint);
|
|
}
|
|
|
|
void SSUSession::SendSessionConfirmed (const uint8_t * y, const uint8_t * ourAddress, uint32_t relayTag)
|
|
{
|
|
auto address = m_RemoteRouter ? m_RemoteRouter->GetSSUAddress () : nullptr;
|
|
if (!address)
|
|
{
|
|
LogPrint ("Missing remote SSU address");
|
|
return;
|
|
}
|
|
|
|
uint8_t buf[480 + 18];
|
|
uint8_t * payload = buf + sizeof (SSUHeader);
|
|
*payload = 1; // 1 fragment
|
|
payload++; // info
|
|
size_t identLen = sizeof (i2p::context.GetRouterIdentity ()); // 387 bytes
|
|
*(uint16_t *)(payload) = htobe16 (identLen);
|
|
payload += 2; // cursize
|
|
memcpy (payload, (uint8_t *)&i2p::context.GetRouterIdentity (), identLen);
|
|
payload += identLen;
|
|
uint32_t signedOnTime = i2p::util::GetSecondsSinceEpoch ();
|
|
*(uint32_t *)(payload) = htobe32 (signedOnTime); // signed on time
|
|
payload += 4;
|
|
size_t paddingSize = ((payload - buf) + 40)%16;
|
|
if (paddingSize > 0) paddingSize = 16 - paddingSize;
|
|
// TODO: fill padding
|
|
payload += paddingSize; // padding size
|
|
|
|
// signature
|
|
uint8_t signedData[532]; // x,y, our IP, our port, remote IP, remote port, relayTag, our signed on time
|
|
memcpy (signedData, i2p::context.GetRouterIdentity ().publicKey, 256); // x
|
|
memcpy (signedData + 256, y, 256); // y
|
|
memcpy (signedData + 512, ourAddress, 6); // our address/port as seem by party
|
|
*(uint32_t *)(signedData + 518) = htobe32 (m_RemoteEndpoint.address ().to_v4 ().to_ulong ()); // remote IP
|
|
*(uint16_t *)(signedData + 522) = htobe16 (m_RemoteEndpoint.port ()); // remote port
|
|
*(uint32_t *)(signedData + 524) = htobe32 (relayTag); // relay tag
|
|
*(uint32_t *)(signedData + 528) = htobe32 (signedOnTime); // signed on time
|
|
i2p::context.Sign (signedData, 532, payload); // DSA signature
|
|
|
|
uint8_t iv[16];
|
|
CryptoPP::RandomNumberGenerator& rnd = i2p::context.GetRandomNumberGenerator ();
|
|
rnd.GenerateBlock (iv, 16); // random iv
|
|
// encrypt message with session key
|
|
FillHeaderAndEncrypt (PAYLOAD_TYPE_SESSION_CONFIRMED, buf, 480, m_SessionKey, iv, m_MacKey);
|
|
m_State = eSessionStateConfirmedSent;
|
|
m_Server->Send (buf, 480, m_RemoteEndpoint);
|
|
}
|
|
|
|
bool SSUSession::ProcessIntroKeyEncryptedMessage (uint8_t expectedPayloadType, i2p::data::RouterInfo& r, uint8_t * buf, size_t len)
|
|
{
|
|
auto address = r.GetSSUAddress ();
|
|
if (address)
|
|
{
|
|
// use intro key for verification and decryption
|
|
if (Validate (buf, len, address->key))
|
|
{
|
|
Decrypt (buf, len, address->key);
|
|
SSUHeader * header = (SSUHeader *)buf;
|
|
if ((header->flag >> 4) == expectedPayloadType)
|
|
{
|
|
CreateAESandMacKey (buf + sizeof (SSUHeader), m_SessionKey, m_MacKey);
|
|
return true;
|
|
}
|
|
else
|
|
LogPrint ("Unexpected payload type ", (int)(header->flag >> 4));
|
|
}
|
|
else
|
|
LogPrint ("MAC verifcation failed");
|
|
}
|
|
else
|
|
LogPrint ("SSU is not supported by ", r.GetIdentHashAbbreviation ());
|
|
return false;
|
|
}
|
|
|
|
void SSUSession::FillHeaderAndEncrypt (uint8_t payloadType, uint8_t * buf, size_t len, uint8_t * aesKey, uint8_t * iv, uint8_t * macKey)
|
|
{
|
|
if (len < sizeof (SSUHeader))
|
|
{
|
|
LogPrint ("Unexpected SSU packet length ", len);
|
|
return;
|
|
}
|
|
SSUHeader * header = (SSUHeader *)buf;
|
|
memcpy (header->iv, iv, 16);
|
|
header->flag = payloadType << 4; // MSB is 0
|
|
header->time = htobe32 (i2p::util::GetSecondsSinceEpoch ());
|
|
uint8_t * encrypted = &header->flag;
|
|
uint16_t encryptedLen = len - (encrypted - buf);
|
|
m_Encryption.SetKeyWithIV (aesKey, 32, iv);
|
|
m_Encryption.ProcessData (encrypted, encrypted, encryptedLen);
|
|
// assume actual buffer size is 18 (16 + 2) bytes more
|
|
memcpy (buf + len, iv, 16);
|
|
*(uint16_t *)(buf + len + 16) = htobe16 (encryptedLen);
|
|
i2p::crypto::HMACMD5Digest (encrypted, encryptedLen + 18, macKey, header->mac);
|
|
}
|
|
|
|
void SSUSession::Decrypt (uint8_t * buf, size_t len, uint8_t * aesKey)
|
|
{
|
|
if (len < sizeof (SSUHeader))
|
|
{
|
|
LogPrint ("Unexpected SSU packet length ", len);
|
|
return;
|
|
}
|
|
SSUHeader * header = (SSUHeader *)buf;
|
|
uint8_t * encrypted = &header->flag;
|
|
uint16_t encryptedLen = len - (encrypted - buf);
|
|
m_Decryption.SetKeyWithIV (aesKey, 32, header->iv);
|
|
encryptedLen = (encryptedLen/16)*16; // make sure 16 bytes boundary
|
|
m_Decryption.ProcessData (encrypted, encrypted, encryptedLen);
|
|
}
|
|
|
|
bool SSUSession::Validate (uint8_t * buf, size_t len, uint8_t * macKey)
|
|
{
|
|
if (len < sizeof (SSUHeader))
|
|
{
|
|
LogPrint ("Unexpected SSU packet length ", len);
|
|
return false;
|
|
}
|
|
SSUHeader * header = (SSUHeader *)buf;
|
|
uint8_t * encrypted = &header->flag;
|
|
uint16_t encryptedLen = len - (encrypted - buf);
|
|
// assume actual buffer size is 18 (16 + 2) bytes more
|
|
memcpy (buf + len, header->iv, 16);
|
|
*(uint16_t *)(buf + len + 16) = htobe16 (encryptedLen);
|
|
uint8_t digest[16];
|
|
i2p::crypto::HMACMD5Digest (encrypted, encryptedLen + 18, macKey, digest);
|
|
return !memcmp (header->mac, digest, 16);
|
|
}
|
|
|
|
void SSUSession::Connect ()
|
|
{
|
|
SendSessionRequest ();
|
|
}
|
|
|
|
void SSUSession::SendI2NPMessage (I2NPMessage * msg)
|
|
{
|
|
// TODO:
|
|
}
|
|
|
|
SSUServer::SSUServer (boost::asio::io_service& service, int port):
|
|
m_Endpoint (boost::asio::ip::udp::v4 (), port), m_Socket (service, m_Endpoint)
|
|
{
|
|
}
|
|
|
|
SSUServer::~SSUServer ()
|
|
{
|
|
for (auto it: m_Sessions)
|
|
delete it.second;
|
|
}
|
|
|
|
void SSUServer::Start ()
|
|
{
|
|
Receive ();
|
|
}
|
|
|
|
void SSUServer::Stop ()
|
|
{
|
|
m_Socket.close ();
|
|
}
|
|
|
|
void SSUServer::Send (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& to)
|
|
{
|
|
m_Socket.send_to (boost::asio::buffer (buf, len), to);
|
|
}
|
|
|
|
void SSUServer::Receive ()
|
|
{
|
|
m_Socket.async_receive_from (boost::asio::buffer (m_ReceiveBuffer, SSU_MTU), m_SenderEndpoint,
|
|
boost::bind (&SSUServer::HandleReceivedFrom, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred));
|
|
}
|
|
|
|
void SSUServer::HandleReceivedFrom (const boost::system::error_code& ecode, std::size_t bytes_transferred)
|
|
{
|
|
if (!ecode)
|
|
{
|
|
LogPrint ("SSU received ", bytes_transferred, " bytes");
|
|
SSUSession * session = nullptr;
|
|
auto it = m_Sessions.find (m_SenderEndpoint);
|
|
if (it != m_Sessions.end ())
|
|
session = it->second;
|
|
if (!session)
|
|
{
|
|
session = new SSUSession (this, m_SenderEndpoint);
|
|
m_Sessions[m_SenderEndpoint] = session;
|
|
LogPrint ("New SSU session from ", m_SenderEndpoint.address ().to_string (), ":", m_SenderEndpoint.port (), " created");
|
|
}
|
|
session->ProcessNextMessage (m_ReceiveBuffer, bytes_transferred, m_SenderEndpoint);
|
|
Receive ();
|
|
}
|
|
else
|
|
LogPrint ("SSU receive error: ", ecode.message ());
|
|
}
|
|
|
|
SSUSession * SSUServer::GetSession (i2p::data::RouterInfo * router)
|
|
{
|
|
SSUSession * session = nullptr;
|
|
if (router)
|
|
{
|
|
auto address = router->GetSSUAddress ();
|
|
if (address)
|
|
{
|
|
boost::asio::ip::udp::endpoint remoteEndpoint (address->host, address->port);
|
|
auto it = m_Sessions.find (remoteEndpoint);
|
|
if (it != m_Sessions.end ())
|
|
session = it->second;
|
|
else
|
|
{
|
|
// otherwise create new session
|
|
session = new SSUSession (this, remoteEndpoint, router);
|
|
m_Sessions[remoteEndpoint] = session;
|
|
LogPrint ("New SSU session to [", router->GetIdentHashAbbreviation (), "] ",
|
|
remoteEndpoint.address ().to_string (), ":", remoteEndpoint.port (), " created");
|
|
session->Connect ();
|
|
}
|
|
}
|
|
else
|
|
LogPrint ("Router ", router->GetIdentHashAbbreviation (), " doesn't have SSU address");
|
|
}
|
|
return session;
|
|
}
|
|
}
|
|
}
|
|
|