From 7473d8c9aaf3f24f140bbd6949f68783137fb60e Mon Sep 17 00:00:00 2001 From: orignal Date: Wed, 16 Mar 2022 13:13:31 -0400 Subject: [PATCH] create and handle Address block --- libi2pd/SSU2.cpp | 80 ++++++++++++++++++++++++++++++++++++++++++++---- libi2pd/SSU2.h | 2 ++ 2 files changed, 76 insertions(+), 6 deletions(-) diff --git a/libi2pd/SSU2.cpp b/libi2pd/SSU2.cpp index 57564d92..902f1371 100644 --- a/libi2pd/SSU2.cpp +++ b/libi2pd/SSU2.cpp @@ -54,7 +54,7 @@ namespace transport m_EphemeralKeys = i2p::transport::transports.GetNextX25519KeysPair (); Header header; - uint8_t headerX[48], payload[48]; + uint8_t headerX[48], payload[40]; // fill packet RAND_bytes ((uint8_t *)&m_DestConnID, 8); header.h.connID = m_DestConnID; // dest id @@ -72,7 +72,7 @@ namespace transport htobe16buf (payload + 1, 4); htobe32buf (payload + 3, i2p::util::GetSecondsSinceEpoch ()); size_t payloadSize = 7; - uint8_t paddingSize = (rand () & 0x0F) + 9; // 9 - 24 + uint8_t paddingSize = (rand () & 0x0F) + 1; // 1 - 16 payload[payloadSize] = eSSU2BlkPadding; htobe16buf (payload + payloadSize + 1, paddingSize); payloadSize += paddingSize + 3; @@ -89,7 +89,7 @@ namespace transport 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); - m_NoiseState->MixHash (payload, 32); // h = SHA256(h || 32 byte encrypted payload from Session Request) for SessionCreated + m_NoiseState->MixHash (payload, 24); // h = SHA256(h || 24 byte encrypted payload from Session Request) for SessionCreated // send m_Server.AddPendingOutgoingSession (boost::asio::ip::udp::endpoint (m_Address->host, m_Address->port), shared_from_this ()); m_Server.Send (header.buf, 16, headerX, 48, payload, payloadSize, m_RemoteEndpoint); @@ -120,6 +120,7 @@ namespace transport m_NoiseState->MixKey (sharedSecret); // decrypt uint8_t * payload = buf + 64; + m_NoiseState->MixHash (payload, 24); // h = SHA256(h || 24 byte encrypted payload from Session Request) for SessionCreated if (!i2p::crypto::AEADChaCha20Poly1305 (payload, len - 80, m_NoiseState->m_H, 32, m_NoiseState->m_CK + 32, nonce, payload, len - 80, false)) { LogPrint (eLogWarning, "SSU2: SessionRequest AEAD verification failed "); @@ -139,8 +140,7 @@ namespace transport // fill packet Header header; - uint8_t headerX[48], payload[1200]; // TODO: correct payload size - size_t payloadSize = 8; + uint8_t headerX[48], payload[64]; header.h.connID = m_DestConnID; // dest id memset (header.h.packetNum, 0, 4); header.h.type = eSSU2SessionCreated; @@ -150,6 +150,19 @@ namespace transport memcpy (headerX, &m_SourceConnID, 8); // source id RAND_bytes (headerX + 8, 8); // token memcpy (headerX + 16, m_EphemeralKeys->GetPublicKey (), 32); // Y + // payload + payload[0] = eSSU2BlkDateTime; + htobe16buf (payload + 1, 4); + htobe32buf (payload + 3, i2p::util::GetSecondsSinceEpoch ()); + size_t payloadSize = 7; + payloadSize += CreateAddressBlock (m_RemoteEndpoint, payload, 57); + uint8_t paddingSize = rand () & 0x0F; // 0 - 15 + if (paddingSize) + { + payload[payloadSize] = eSSU2BlkPadding; + htobe16buf (payload + payloadSize + 1, paddingSize); + payloadSize += paddingSize + 3; + } // 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); @@ -253,7 +266,12 @@ namespace transport case eSSU2BlkAck: break; case eSSU2BlkAddress: - break; + { + boost::asio::ip::udp::endpoint ep; + if (ExtractEndpoint (buf + offset, size, ep)) + LogPrint (eLogInfo, "SSU2: Our external address is ", ep); + break; + } case eSSU2BlkIntroKey: break; case eSSU2BlkRelayTagRequest: @@ -277,6 +295,56 @@ namespace transport offset += size; } } + + bool SSU2Session::ExtractEndpoint (const uint8_t * buf, size_t size, boost::asio::ip::udp::endpoint& ep) + { + if (size < 2) return false; + int port = bufbe16toh (buf); + if (size == 6) + { + boost::asio::ip::address_v4::bytes_type bytes; + memcpy (bytes.data (), buf + 2, 4); + ep = boost::asio::ip::udp::endpoint (boost::asio::ip::address_v4 (bytes), port); + } + else if (size == 18) + { + boost::asio::ip::address_v6::bytes_type bytes; + memcpy (bytes.data (), buf + 2, 16); + ep = boost::asio::ip::udp::endpoint (boost::asio::ip::address_v6 (bytes), port); + } + else + { + LogPrint (eLogWarning, "SSU2: Address size ", int(size), " is not supported"); + return false; + } + return true; + } + + size_t SSU2Session::CreateAddressBlock (const boost::asio::ip::udp::endpoint& ep, uint8_t * buf, size_t len) + { + if (len < 9) return 0; + buf[0] = eSSU2BlkAddress; + htobe16buf (buf + 3, ep.port ()); + size_t size = 0; + if (ep.address ().is_v4 ()) + { + memcpy (buf + 5, ep.address ().to_v4 ().to_bytes ().data (), 4); + size = 6; + } + else if (ep.address ().is_v6 ()) + { + if (len < 21) return 0; + memcpy (buf + 5, ep.address ().to_v6 ().to_bytes ().data (), 16); + size = 18; + } + else + { + LogPrint (eLogWarning, "SSU2: Wrong address type ", ep.address ().to_string ()); + return 0; + } + htobe16buf (buf + 1, size); + return size + 3; + } SSU2Server::SSU2Server (): RunnableServiceWithWork ("SSU2"), m_Socket (GetService ()) diff --git a/libi2pd/SSU2.h b/libi2pd/SSU2.h index ddd20fa2..d1e67590 100644 --- a/libi2pd/SSU2.h +++ b/libi2pd/SSU2.h @@ -94,6 +94,8 @@ namespace transport void SendSessionCreated (const uint8_t * X); void HandlePayload (const uint8_t * buf, size_t len); + bool ExtractEndpoint (const uint8_t * buf, size_t size, boost::asio::ip::udp::endpoint& ep); + size_t CreateAddressBlock (const boost::asio::ip::udp::endpoint& ep, uint8_t * buf, size_t len); private: