From 7faa732f38e2cae622b91364e19751f26d64c0c3 Mon Sep 17 00:00:00 2001 From: orignal Date: Tue, 8 Mar 2022 21:33:21 -0500 Subject: [PATCH] send SessionCreated --- libi2pd/SSU2.cpp | 75 +++++++++++++++++++++++++++++++++++++----------- libi2pd/SSU2.h | 19 +++++------- 2 files changed, 65 insertions(+), 29 deletions(-) diff --git a/libi2pd/SSU2.cpp b/libi2pd/SSU2.cpp index 251b4296..802f398c 100644 --- a/libi2pd/SSU2.cpp +++ b/libi2pd/SSU2.cpp @@ -30,10 +30,11 @@ namespace transport m_Server (server), m_Address (addr), m_DestConnID (0), m_SourceConnID (0) { m_NoiseState.reset (new i2p::crypto::NoiseSymmetricState); - if (in_RemoteRouter && addr) + if (in_RemoteRouter && m_Address) { // outgoing - InitNoiseXKState1 (*m_NoiseState, addr->s); + InitNoiseXKState1 (*m_NoiseState, m_Address->s); + m_RemoteEndpoint = boost::asio::ip::udp::endpoint (m_Address->host, m_Address->port); } else { @@ -48,6 +49,7 @@ namespace transport void SSU2Session::SendSessionRequest () { + // we are Alice m_EphemeralKeys = i2p::transport::transports.GetNextX25519KeysPair (); Header header; @@ -56,11 +58,11 @@ namespace transport // fill packet RAND_bytes ((uint8_t *)&m_DestConnID, 8); header.h.connID = m_DestConnID; // dest id - memset (header.h.h2.h.packetNum, 0, 4); - header.h.h2.h.type = eSSU2SessionRequest; - header.h.h2.h.flags[0] = 2; // ver - header.h.h2.h.flags[1] = (uint8_t)i2p::context.GetNetID (); // netID - header.h.h2.h.flags[2] = 0; // flag + memset (header.h.packetNum, 0, 4); + header.h.type = eSSU2SessionRequest; + header.h.flags[0] = 2; // ver + header.h.flags[1] = (uint8_t)i2p::context.GetNetID (); // netID + header.h.flags[2] = 0; // flag RAND_bytes ((uint8_t *)&m_SourceConnID, 8); memcpy (headerX, &m_SourceConnID, 8); // source id RAND_bytes (headerX + 8, 8); // token @@ -75,13 +77,13 @@ namespace transport // encrypt const uint8_t nonce[12] = {0}; i2p::crypto::AEADChaCha20Poly1305 (payload, payloadSize, m_NoiseState->m_H, 32, m_NoiseState->m_CK + 32, nonce, payload, payloadSize + 16, true); + payloadSize += 16; header.ll[0] ^= CreateHeaderMask (m_Address->i, payload + (payloadSize - 24)); header.ll[1] ^= CreateHeaderMask (m_Address->i, payload + (payloadSize - 12)); i2p::crypto::ChaCha20 (headerX, 48, m_Address->i, nonce, headerX); - payloadSize += 16; m_NoiseState->MixHash (payload, 32); // h = SHA256(h || 32 byte encrypted payload from Session Request) for SessionCreated // send - m_Server.Send (header.buf, 16, headerX, 48, payload, payloadSize, boost::asio::ip::udp::endpoint (m_Address->host, m_Address->port)); + m_Server.Send (header.buf, 16, headerX, 48, payload, payloadSize, m_RemoteEndpoint); } void SSU2Session::ProcessSessionRequest (uint64_t connID, uint8_t * buf, size_t len) @@ -90,11 +92,11 @@ namespace transport m_SourceConnID = connID; Header header; header.h.connID = connID; - memcpy (header.h.h2.buf, buf, 8); - header.h.h2.ll ^= CreateHeaderMask (i2p::context.GetSSU2IntroKey (), buf + (len - 12)); - if (header.h.h2.h.type != eSSU2SessionRequest) + memcpy (header.buf + 8, buf + 8, 8); + header.ll[1] ^= CreateHeaderMask (i2p::context.GetSSU2IntroKey (), buf + (len - 12)); + if (header.h.type != eSSU2SessionRequest) { - LogPrint (eLogWarning, "SSU2: Unexpected message type ", (int)header.h.h2.h.type); + LogPrint (eLogWarning, "SSU2: Unexpected message type ", (int)header.h.type); return; } const uint8_t nonce[12] = {0}; @@ -117,6 +119,44 @@ namespace transport // process payload m_Server.AddSession (m_SourceConnID, shared_from_this ()); + SendSessionCreated (headerX + 16); + } + + void SSU2Session::SendSessionCreated (const uint8_t * X) + { + // we are Bob + m_EphemeralKeys = i2p::transport::transports.GetNextX25519KeysPair (); + + // fill packet + Header header; + uint8_t headerX[48], payload[1200]; // TODO: correct payload size + size_t payloadSize = 8; + header.h.connID = m_DestConnID; // dest id + memset (header.h.packetNum, 0, 4); + header.h.type = eSSU2SessionCreated; + header.h.flags[0] = 2; // ver + header.h.flags[1] = (uint8_t)i2p::context.GetNetID (); // netID + header.h.flags[2] = 0; // flag + memcpy (headerX, &m_SourceConnID, 8); // source id + RAND_bytes (headerX + 8, 8); // token + memcpy (headerX + 16, m_EphemeralKeys->GetPublicKey (), 32); // Y + // KDF for SessionCreated + m_NoiseState->MixHash ( { {header.buf, 16}, {headerX, 16} } ); // h = SHA256(h || header) + m_NoiseState->MixHash (headerX + 16, 32); // h = SHA256(h || bepk); + uint8_t sharedSecret[32]; + m_EphemeralKeys->Agree (X, sharedSecret); + m_NoiseState->MixKey (sharedSecret); + // encrypt + const uint8_t nonce[12] = {0}; + i2p::crypto::AEADChaCha20Poly1305 (payload, payloadSize, m_NoiseState->m_H, 32, m_NoiseState->m_CK + 32, nonce, payload, payloadSize + 16, true); + payloadSize += 16; + header.ll[0] ^= CreateHeaderMask (i2p::context.GetSSU2IntroKey (), payload + (payloadSize - 24)); + uint8_t kh2[32]; + i2p::crypto::HKDF (m_NoiseState->m_CK, nullptr, 0, "SessCreateHeader", kh2, 32); // k_header_2 = HKDF(chainKey, ZEROLEN, "SessCreateHeader", 32) + header.ll[1] ^= CreateHeaderMask (kh2, payload + (payloadSize - 12)); + i2p::crypto::ChaCha20 (headerX, 48, kh2, nonce, headerX); + // send + m_Server.Send (header.buf, 16, headerX, 48, payload, payloadSize, m_RemoteEndpoint); } bool SSU2Session::ProcessSessionCreated (uint8_t * buf, size_t len) @@ -124,13 +164,13 @@ namespace transport // we are Alice Header header; header.h.connID = m_SourceConnID; - memcpy (header.h.h2.buf, buf, 8); + memcpy (header.buf + 8, buf + 8, 8); uint8_t kh2[32]; i2p::crypto::HKDF (m_NoiseState->m_CK, nullptr, 0, "SessCreateHeader", kh2, 32); // k_header_2 = HKDF(chainKey, ZEROLEN, "SessCreateHeader", 32) - header.h.h2.ll ^= CreateHeaderMask (kh2, buf + (len - 12)); - if (header.h.h2.h.type != eSSU2SessionCreated) + header.ll[1] ^= CreateHeaderMask (kh2, buf + (len - 12)); + if (header.h.type != eSSU2SessionCreated) { - LogPrint (eLogWarning, "SSU2: Unexpected message type ", (int)header.h.h2.h.type); + LogPrint (eLogWarning, "SSU2: Unexpected message type ", (int)header.h.type); return false; } const uint8_t nonce[12] = {0}; @@ -210,6 +250,7 @@ namespace transport { // assume new incoming session auto session = std::make_shared (*this); + session->SetRemoteEndpoint (senderEndpoint); session->ProcessSessionRequest (connID, buf, len); } } diff --git a/libi2pd/SSU2.h b/libi2pd/SSU2.h index 613617bc..99abb06b 100644 --- a/libi2pd/SSU2.h +++ b/libi2pd/SSU2.h @@ -34,17 +34,6 @@ namespace transport class SSU2Server; class SSU2Session: public TransportSession, public std::enable_shared_from_this { - union Header2 - { - uint64_t ll; - uint8_t buf[8]; - struct - { - uint8_t packetNum[4]; - uint8_t type; - uint8_t flags[3]; - } h; - }; union Header { uint64_t ll[2]; @@ -52,7 +41,9 @@ namespace transport struct { uint64_t connID; - Header2 h2; + uint8_t packetNum[4]; + uint8_t type; + uint8_t flags[3]; } h; }; @@ -62,6 +53,8 @@ namespace transport std::shared_ptr addr = nullptr, bool peerTest = false); ~SSU2Session (); + void SetRemoteEndpoint (const boost::asio::ip::udp::endpoint& ep) { m_RemoteEndpoint = ep; }; + void Done () override {}; void SendI2NPMessages (const std::vector >& msgs) override {}; @@ -71,6 +64,7 @@ namespace transport private: void SendSessionRequest (); + void SendSessionCreated (const uint8_t * X); private: @@ -78,6 +72,7 @@ namespace transport std::shared_ptr m_EphemeralKeys; std::unique_ptr m_NoiseState; std::shared_ptr m_Address; + boost::asio::ip::udp::endpoint m_RemoteEndpoint; uint64_t m_DestConnID, m_SourceConnID; };