mirror of
https://github.com/PurpleI2P/i2pd.git
synced 2024-11-17 21:26:04 +00:00
297 lines
10 KiB
C++
297 lines
10 KiB
C++
/*
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* Copyright (c) 2022, The PurpleI2P Project
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*
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* This file is part of Purple i2pd project and licensed under BSD3
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*
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* See full license text in LICENSE file at top of project tree
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*/
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#include <string.h>
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#include <openssl/rand.h>
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#include "Log.h"
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#include "RouterContext.h"
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#include "Transports.h"
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#include "SSU2.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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static uint64_t CreateHeaderMask (const uint8_t * kh, const uint8_t * nonce)
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{
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uint64_t data = 0;
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i2p::crypto::ChaCha20 ((uint8_t *)&data, 8, kh, nonce, (uint8_t *)&data);
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return data;
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}
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SSU2Session::SSU2Session (SSU2Server& server, std::shared_ptr<const i2p::data::RouterInfo> in_RemoteRouter,
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std::shared_ptr<const i2p::data::RouterInfo::Address> addr, bool peerTest):
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TransportSession (in_RemoteRouter, SSU2_TERMINATION_TIMEOUT),
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m_Server (server), m_Address (addr), m_DestConnID (0), m_SourceConnID (0)
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{
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m_NoiseState.reset (new i2p::crypto::NoiseSymmetricState);
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if (in_RemoteRouter && m_Address)
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{
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// outgoing
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InitNoiseXKState1 (*m_NoiseState, m_Address->s);
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m_RemoteEndpoint = boost::asio::ip::udp::endpoint (m_Address->host, m_Address->port);
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}
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else
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{
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// incoming
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InitNoiseXKState1 (*m_NoiseState, i2p::context.GetSSU2StaticPublicKey ());
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}
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}
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SSU2Session::~SSU2Session ()
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{
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}
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void SSU2Session::SendSessionRequest ()
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{
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// we are Alice
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m_EphemeralKeys = i2p::transport::transports.GetNextX25519KeysPair ();
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Header header;
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uint8_t headerX[48], payload[1200]; // TODO: correct payload size
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size_t payloadSize = 8;
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// fill packet
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RAND_bytes ((uint8_t *)&m_DestConnID, 8);
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header.h.connID = m_DestConnID; // dest id
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memset (header.h.packetNum, 0, 4);
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header.h.type = eSSU2SessionRequest;
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header.h.flags[0] = 2; // ver
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header.h.flags[1] = (uint8_t)i2p::context.GetNetID (); // netID
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header.h.flags[2] = 0; // flag
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RAND_bytes ((uint8_t *)&m_SourceConnID, 8);
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memcpy (headerX, &m_SourceConnID, 8); // source id
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RAND_bytes (headerX + 8, 8); // token
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memcpy (headerX + 16, m_EphemeralKeys->GetPublicKey (), 32); // X
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m_Server.AddPendingOutgoingSession (boost::asio::ip::udp::endpoint (m_Address->host, m_Address->port), shared_from_this ());
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// KDF for session request
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m_NoiseState->MixHash ({ {header.buf, 16}, {headerX, 16} }); // h = SHA256(h || header)
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m_NoiseState->MixHash (m_EphemeralKeys->GetPublicKey (), 32); // h = SHA256(h || aepk);
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uint8_t sharedSecret[32];
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m_EphemeralKeys->Agree (m_Address->s, sharedSecret);
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m_NoiseState->MixKey (sharedSecret);
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// encrypt
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const uint8_t nonce[12] = {0};
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i2p::crypto::AEADChaCha20Poly1305 (payload, payloadSize, m_NoiseState->m_H, 32, m_NoiseState->m_CK + 32, nonce, payload, payloadSize + 16, true);
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payloadSize += 16;
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header.ll[0] ^= CreateHeaderMask (m_Address->i, payload + (payloadSize - 24));
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header.ll[1] ^= CreateHeaderMask (m_Address->i, payload + (payloadSize - 12));
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i2p::crypto::ChaCha20 (headerX, 48, m_Address->i, nonce, headerX);
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m_NoiseState->MixHash (payload, 32); // h = SHA256(h || 32 byte encrypted payload from Session Request) for SessionCreated
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// send
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m_Server.Send (header.buf, 16, headerX, 48, payload, payloadSize, m_RemoteEndpoint);
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}
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void SSU2Session::ProcessSessionRequest (uint64_t connID, uint8_t * buf, size_t len)
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{
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// we are Bob
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m_SourceConnID = connID;
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Header header;
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header.h.connID = connID;
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memcpy (header.buf + 8, buf + 8, 8);
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header.ll[1] ^= CreateHeaderMask (i2p::context.GetSSU2IntroKey (), buf + (len - 12));
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if (header.h.type != eSSU2SessionRequest)
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{
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LogPrint (eLogWarning, "SSU2: Unexpected message type ", (int)header.h.type);
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return;
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}
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const uint8_t nonce[12] = {0};
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uint8_t headerX[48];
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i2p::crypto::ChaCha20 (buf + 16, 48, i2p::context.GetSSU2IntroKey (), nonce, headerX);
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memcpy (&m_DestConnID, headerX, 8);
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// KDF for session request
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m_NoiseState->MixHash ( { {header.buf, 16}, {headerX, 16} } ); // h = SHA256(h || header)
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m_NoiseState->MixHash (headerX + 16, 32); // h = SHA256(h || aepk);
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uint8_t sharedSecret[32];
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i2p::context.GetSSU2StaticKeys ().Agree (headerX + 16, sharedSecret);
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m_NoiseState->MixKey (sharedSecret);
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// decrypt
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uint8_t * payload = buf + 64;
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if (!i2p::crypto::AEADChaCha20Poly1305 (payload, len - 80, m_NoiseState->m_H, 32, m_NoiseState->m_CK + 32, nonce, payload, len - 80, false))
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{
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LogPrint (eLogWarning, "SSU2: SessionRequest AEAD verification failed ");
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return;
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}
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// process payload
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m_Server.AddSession (m_SourceConnID, shared_from_this ());
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SendSessionCreated (headerX + 16);
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}
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void SSU2Session::SendSessionCreated (const uint8_t * X)
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{
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// we are Bob
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m_EphemeralKeys = i2p::transport::transports.GetNextX25519KeysPair ();
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// fill packet
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Header header;
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uint8_t headerX[48], payload[1200]; // TODO: correct payload size
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size_t payloadSize = 8;
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header.h.connID = m_DestConnID; // dest id
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memset (header.h.packetNum, 0, 4);
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header.h.type = eSSU2SessionCreated;
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header.h.flags[0] = 2; // ver
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header.h.flags[1] = (uint8_t)i2p::context.GetNetID (); // netID
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header.h.flags[2] = 0; // flag
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memcpy (headerX, &m_SourceConnID, 8); // source id
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RAND_bytes (headerX + 8, 8); // token
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memcpy (headerX + 16, m_EphemeralKeys->GetPublicKey (), 32); // Y
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// KDF for SessionCreated
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m_NoiseState->MixHash ( { {header.buf, 16}, {headerX, 16} } ); // h = SHA256(h || header)
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m_NoiseState->MixHash (headerX + 16, 32); // h = SHA256(h || bepk);
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uint8_t sharedSecret[32];
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m_EphemeralKeys->Agree (X, sharedSecret);
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m_NoiseState->MixKey (sharedSecret);
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// encrypt
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const uint8_t nonce[12] = {0};
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i2p::crypto::AEADChaCha20Poly1305 (payload, payloadSize, m_NoiseState->m_H, 32, m_NoiseState->m_CK + 32, nonce, payload, payloadSize + 16, true);
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payloadSize += 16;
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header.ll[0] ^= CreateHeaderMask (i2p::context.GetSSU2IntroKey (), payload + (payloadSize - 24));
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uint8_t kh2[32];
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i2p::crypto::HKDF (m_NoiseState->m_CK, nullptr, 0, "SessCreateHeader", kh2, 32); // k_header_2 = HKDF(chainKey, ZEROLEN, "SessCreateHeader", 32)
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header.ll[1] ^= CreateHeaderMask (kh2, payload + (payloadSize - 12));
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i2p::crypto::ChaCha20 (headerX, 48, kh2, nonce, headerX);
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// send
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m_Server.Send (header.buf, 16, headerX, 48, payload, payloadSize, m_RemoteEndpoint);
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}
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bool SSU2Session::ProcessSessionCreated (uint8_t * buf, size_t len)
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{
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// we are Alice
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Header header;
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header.h.connID = m_SourceConnID;
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memcpy (header.buf + 8, buf + 8, 8);
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uint8_t kh2[32];
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i2p::crypto::HKDF (m_NoiseState->m_CK, nullptr, 0, "SessCreateHeader", kh2, 32); // k_header_2 = HKDF(chainKey, ZEROLEN, "SessCreateHeader", 32)
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header.ll[1] ^= CreateHeaderMask (kh2, buf + (len - 12));
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if (header.h.type != eSSU2SessionCreated)
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{
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LogPrint (eLogWarning, "SSU2: Unexpected message type ", (int)header.h.type);
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return false;
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}
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const uint8_t nonce[12] = {0};
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uint8_t headerX[48];
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i2p::crypto::ChaCha20 (buf + 16, 48, kh2, nonce, headerX);
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// KDF for SessionCreated
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m_NoiseState->MixHash ( { {header.buf, 16}, {headerX, 16} } ); // h = SHA256(h || header)
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m_NoiseState->MixHash (headerX + 16, 32); // h = SHA256(h || bepk);
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uint8_t sharedSecret[32];
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m_EphemeralKeys->Agree (headerX + 16, sharedSecret);
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m_NoiseState->MixKey (sharedSecret);
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// decrypt
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uint8_t * payload = buf + 64;
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if (!i2p::crypto::AEADChaCha20Poly1305 (payload, len - 80, m_NoiseState->m_H, 32, m_NoiseState->m_CK + 32, nonce, payload, len - 80, false))
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{
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LogPrint (eLogWarning, "SSU2: SessionCreated AEAD verification failed ");
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return false;
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}
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// process payload
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m_Server.AddSession (m_SourceConnID, shared_from_this ());
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return true;
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}
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SSU2Server::SSU2Server ():
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RunnableServiceWithWork ("SSU2"), m_Socket (GetService ())
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{
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}
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void SSU2Server::Start ()
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{
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if (!IsRunning ())
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{
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StartIOService ();
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auto& addresses = i2p::context.GetRouterInfo ().GetAddresses ();
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for (const auto& address: addresses)
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{
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if (!address) continue;
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if (address->transportStyle == i2p::data::RouterInfo::eTransportSSU2 && address->port)
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{
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OpenSocket (address->port);
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break;
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}
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}
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}
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}
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void SSU2Server::Stop ()
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{
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StopIOService ();
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}
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void SSU2Server::OpenSocket (int port)
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{
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try
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{
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m_Socket.open (boost::asio::ip::udp::v6());
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m_Socket.set_option (boost::asio::socket_base::receive_buffer_size (SSU2_SOCKET_RECEIVE_BUFFER_SIZE));
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m_Socket.set_option (boost::asio::socket_base::send_buffer_size (SSU2_SOCKET_SEND_BUFFER_SIZE));
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m_Socket.bind (boost::asio::ip::udp::endpoint (boost::asio::ip::udp::v6(), port));
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LogPrint (eLogInfo, "SSU2: Start listening port ", port);
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}
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catch (std::exception& ex )
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{
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LogPrint (eLogError, "SSU2: Failed to bind to port ", port, ": ", ex.what());
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ThrowFatal ("Unable to start SSU2 transport at port ", port, ": ", ex.what ());
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}
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}
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void SSU2Server::AddSession (uint64_t connID, std::shared_ptr<SSU2Session> session)
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{
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m_Sessions.emplace (connID, session);
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}
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void SSU2Server::AddPendingOutgoingSession (const boost::asio::ip::udp::endpoint& ep, std::shared_ptr<SSU2Session> session)
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{
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m_PendingOutgoingSessions.emplace (ep, session);
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}
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void SSU2Server::ProcessNextPacket (uint8_t * buf, size_t len, const boost::asio::ip::udp::endpoint& senderEndpoint)
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{
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uint64_t connID;
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memcpy (&connID, buf, 8);
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connID ^= CreateHeaderMask (i2p::context.GetSSU2IntroKey (), buf + (len - 24));
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auto it = m_Sessions.find (connID);
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if (it != m_Sessions.end ())
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{
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}
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else
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{
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// check pending sessions if it's SessionCreated
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auto it1 = m_PendingOutgoingSessions.find (senderEndpoint);
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if (it1 != m_PendingOutgoingSessions.end ())
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{
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if (it1->second->ProcessSessionCreated (buf, len))
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m_PendingOutgoingSessions.erase (it1);
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}
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else
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{
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// assume new incoming session
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auto session = std::make_shared<SSU2Session> (*this);
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session->SetRemoteEndpoint (senderEndpoint);
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session->ProcessSessionRequest (connID, buf, len);
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}
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}
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}
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void SSU2Server::Send (const uint8_t * header, size_t headerLen, const uint8_t * headerX, size_t headerXLen,
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const uint8_t * payload, size_t payloadLen, const boost::asio::ip::udp::endpoint& to)
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{
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std::vector<boost::asio::const_buffer> bufs
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{
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boost::asio::buffer (header, headerLen),
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boost::asio::buffer (headerX, headerXLen),
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boost::asio::buffer (payload, payloadLen)
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};
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boost::system::error_code ec;
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m_Socket.send_to (bufs, to, 0, ec);
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}
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}
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}
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