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I2P: End-to-End encrypted and anonymous Internet
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250 lines
8.8 KiB
250 lines
8.8 KiB
/* |
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* Copyright (c) 2013-2021, 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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*/ |
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#include <memory> |
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#include <openssl/rand.h> |
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#include <openssl/sha.h> |
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#include "Log.h" |
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#include "Transports.h" |
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#include "Timestamp.h" |
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#include "I2PEndian.h" |
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#include "I2NPProtocol.h" |
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#include "TunnelConfig.h" |
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namespace i2p |
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{ |
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namespace tunnel |
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{ |
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TunnelHopConfig::TunnelHopConfig (std::shared_ptr<const i2p::data::IdentityEx> r) |
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{ |
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RAND_bytes ((uint8_t *)&tunnelID, 4); |
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if (!tunnelID) tunnelID = 1; // tunnelID can't be zero |
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isGateway = true; |
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isEndpoint = true; |
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ident = r; |
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//nextRouter = nullptr; |
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nextTunnelID = 0; |
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next = nullptr; |
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prev = nullptr; |
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} |
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void TunnelHopConfig::SetNextIdent (const i2p::data::IdentHash& ident) |
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{ |
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nextIdent = ident; |
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isEndpoint = false; |
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RAND_bytes ((uint8_t *)&nextTunnelID, 4); |
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if (!nextTunnelID) nextTunnelID = 1; // tunnelID can't be zero |
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} |
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void TunnelHopConfig::SetReplyHop (uint32_t replyTunnelID, const i2p::data::IdentHash& replyIdent) |
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{ |
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nextIdent = replyIdent; |
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nextTunnelID = replyTunnelID; |
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isEndpoint = true; |
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} |
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void TunnelHopConfig::SetNext (TunnelHopConfig * n) |
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{ |
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next = n; |
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if (next) |
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{ |
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next->prev = this; |
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next->isGateway = false; |
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isEndpoint = false; |
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nextIdent = next->ident->GetIdentHash (); |
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nextTunnelID = next->tunnelID; |
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} |
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} |
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void TunnelHopConfig::SetPrev (TunnelHopConfig * p) |
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{ |
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prev = p; |
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if (prev) |
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{ |
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prev->next = this; |
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prev->isEndpoint = false; |
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isGateway = false; |
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} |
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} |
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void TunnelHopConfig::DecryptRecord (uint8_t * records, int index) const |
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{ |
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uint8_t * record = records + index*TUNNEL_BUILD_RECORD_SIZE; |
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i2p::crypto::CBCDecryption decryption; |
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decryption.SetKey (replyKey); |
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decryption.SetIV (replyIV); |
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decryption.Decrypt(record, TUNNEL_BUILD_RECORD_SIZE, record); |
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} |
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void ECIESTunnelHopConfig::EncryptECIES (const uint8_t * plainText, size_t len, uint8_t * encrypted) |
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{ |
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if (!ident) return; |
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i2p::crypto::InitNoiseNState (*this, ident->GetEncryptionPublicKey ()); |
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auto ephemeralKeys = i2p::transport::transports.GetNextX25519KeysPair (); |
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memcpy (encrypted, ephemeralKeys->GetPublicKey (), 32); |
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MixHash (encrypted, 32); // h = SHA256(h || sepk) |
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encrypted += 32; |
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uint8_t sharedSecret[32]; |
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ephemeralKeys->Agree (ident->GetEncryptionPublicKey (), sharedSecret); // x25519(sesk, hepk) |
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MixKey (sharedSecret); |
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uint8_t nonce[12]; |
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memset (nonce, 0, 12); |
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if (!i2p::crypto::AEADChaCha20Poly1305 (plainText, len, m_H, 32, m_CK + 32, nonce, encrypted, len + 16, true)) // encrypt |
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{ |
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LogPrint (eLogWarning, "Tunnel: Plaintext AEAD encryption failed"); |
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return; |
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} |
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MixHash (encrypted, len + 16); // h = SHA256(h || ciphertext) |
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} |
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bool ECIESTunnelHopConfig::DecryptECIES (const uint8_t * key, const uint8_t * nonce, const uint8_t * encrypted, size_t len, uint8_t * clearText) const |
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{ |
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return i2p::crypto::AEADChaCha20Poly1305 (encrypted, len - 16, m_H, 32, key, nonce, clearText, len - 16, false); // decrypt |
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} |
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void LongECIESTunnelHopConfig::CreateBuildRequestRecord (uint8_t * records, uint32_t replyMsgID) |
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{ |
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// generate keys |
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RAND_bytes (layerKey, 32); |
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RAND_bytes (ivKey, 32); |
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RAND_bytes (replyKey, 32); |
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RAND_bytes (replyIV, 16); |
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// fill clear text |
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uint8_t flag = 0; |
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if (isGateway) flag |= TUNNEL_BUILD_RECORD_GATEWAY_FLAG; |
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if (isEndpoint) flag |= TUNNEL_BUILD_RECORD_ENDPOINT_FLAG; |
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uint8_t clearText[ECIES_BUILD_REQUEST_RECORD_CLEAR_TEXT_SIZE]; |
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htobe32buf (clearText + ECIES_BUILD_REQUEST_RECORD_RECEIVE_TUNNEL_OFFSET, tunnelID); |
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htobe32buf (clearText + ECIES_BUILD_REQUEST_RECORD_NEXT_TUNNEL_OFFSET, nextTunnelID); |
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memcpy (clearText + ECIES_BUILD_REQUEST_RECORD_NEXT_IDENT_OFFSET, nextIdent, 32); |
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memcpy (clearText + ECIES_BUILD_REQUEST_RECORD_LAYER_KEY_OFFSET, layerKey, 32); |
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memcpy (clearText + ECIES_BUILD_REQUEST_RECORD_IV_KEY_OFFSET, ivKey, 32); |
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memcpy (clearText + ECIES_BUILD_REQUEST_RECORD_REPLY_KEY_OFFSET, replyKey, 32); |
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memcpy (clearText + ECIES_BUILD_REQUEST_RECORD_REPLY_IV_OFFSET, replyIV, 16); |
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clearText[ECIES_BUILD_REQUEST_RECORD_FLAG_OFFSET] = flag; |
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memset (clearText + ECIES_BUILD_REQUEST_RECORD_MORE_FLAGS_OFFSET, 0, 3); // set to 0 for compatibility |
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htobe32buf (clearText + ECIES_BUILD_REQUEST_RECORD_REQUEST_TIME_OFFSET, i2p::util::GetMinutesSinceEpoch ()); |
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htobe32buf (clearText + ECIES_BUILD_REQUEST_RECORD_REQUEST_EXPIRATION_OFFSET, 600); // +10 minutes |
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htobe32buf (clearText + ECIES_BUILD_REQUEST_RECORD_SEND_MSG_ID_OFFSET, replyMsgID); |
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memset (clearText + ECIES_BUILD_REQUEST_RECORD_PADDING_OFFSET, 0, ECIES_BUILD_REQUEST_RECORD_CLEAR_TEXT_SIZE - ECIES_BUILD_REQUEST_RECORD_PADDING_OFFSET); |
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// encrypt |
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uint8_t * record = records + recordIndex*TUNNEL_BUILD_RECORD_SIZE; |
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EncryptECIES (clearText, ECIES_BUILD_REQUEST_RECORD_CLEAR_TEXT_SIZE, record + BUILD_REQUEST_RECORD_ENCRYPTED_OFFSET); |
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memcpy (record + BUILD_REQUEST_RECORD_TO_PEER_OFFSET, (const uint8_t *)ident->GetIdentHash (), 16); |
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} |
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bool LongECIESTunnelHopConfig::DecryptBuildResponseRecord (uint8_t * records) const |
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{ |
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uint8_t * record = records + recordIndex*TUNNEL_BUILD_RECORD_SIZE; |
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uint8_t nonce[12]; |
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memset (nonce, 0, 12); |
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if (!DecryptECIES (m_CK, nonce, record, TUNNEL_BUILD_RECORD_SIZE, record)) |
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{ |
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LogPrint (eLogWarning, "Tunnel: Response AEAD decryption failed"); |
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return false; |
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} |
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return true; |
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} |
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void ShortECIESTunnelHopConfig::CreateBuildRequestRecord (uint8_t * records, uint32_t replyMsgID) |
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{ |
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// fill clear text |
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uint8_t flag = 0; |
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if (isGateway) flag |= TUNNEL_BUILD_RECORD_GATEWAY_FLAG; |
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if (isEndpoint) flag |= TUNNEL_BUILD_RECORD_ENDPOINT_FLAG; |
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uint8_t clearText[SHORT_REQUEST_RECORD_CLEAR_TEXT_SIZE ]; |
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htobe32buf (clearText + SHORT_REQUEST_RECORD_RECEIVE_TUNNEL_OFFSET, tunnelID); |
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htobe32buf (clearText + SHORT_REQUEST_RECORD_NEXT_TUNNEL_OFFSET, nextTunnelID); |
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memcpy (clearText + SHORT_REQUEST_RECORD_NEXT_IDENT_OFFSET, nextIdent, 32); |
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clearText[SHORT_REQUEST_RECORD_FLAG_OFFSET] = flag; |
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memset (clearText + SHORT_REQUEST_RECORD_MORE_FLAGS_OFFSET, 0, 2); |
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clearText[SHORT_REQUEST_RECORD_LAYER_ENCRYPTION_TYPE] = 0; // AES |
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htobe32buf (clearText + SHORT_REQUEST_RECORD_REQUEST_TIME_OFFSET, i2p::util::GetMinutesSinceEpoch ()); |
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htobe32buf (clearText + SHORT_REQUEST_RECORD_REQUEST_EXPIRATION_OFFSET , 600); // +10 minutes |
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htobe32buf (clearText + SHORT_REQUEST_RECORD_SEND_MSG_ID_OFFSET, replyMsgID); |
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memset (clearText + SHORT_REQUEST_RECORD_PADDING_OFFSET, 0, SHORT_REQUEST_RECORD_CLEAR_TEXT_SIZE - SHORT_REQUEST_RECORD_PADDING_OFFSET); |
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// encrypt |
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uint8_t * record = records + recordIndex*SHORT_TUNNEL_BUILD_RECORD_SIZE; |
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EncryptECIES (clearText, SHORT_REQUEST_RECORD_CLEAR_TEXT_SIZE, record + SHORT_REQUEST_RECORD_ENCRYPTED_OFFSET); |
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// derive keys |
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i2p::crypto::HKDF (m_CK, nullptr, 0, "SMTunnelReplyKey", m_CK); |
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memcpy (replyKey, m_CK + 32, 32); |
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i2p::crypto::HKDF (m_CK, nullptr, 0, "SMTunnelLayerKey", m_CK); |
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memcpy (layerKey, m_CK + 32, 32); |
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if (isEndpoint) |
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{ |
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i2p::crypto::HKDF (m_CK, nullptr, 0, "TunnelLayerIVKey", m_CK); |
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memcpy (ivKey, m_CK + 32, 32); |
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i2p::crypto::HKDF (m_CK, nullptr, 0, "RGarlicKeyAndTag", m_CK); // OTBRM garlic key m_CK + 32, tag first 8 bytes of m_CK |
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} |
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else |
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memcpy (ivKey, m_CK, 32); // last HKDF |
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memcpy (record + BUILD_REQUEST_RECORD_TO_PEER_OFFSET, (const uint8_t *)ident->GetIdentHash (), 16); |
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} |
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bool ShortECIESTunnelHopConfig::DecryptBuildResponseRecord (uint8_t * records) const |
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{ |
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uint8_t * record = records + recordIndex*SHORT_TUNNEL_BUILD_RECORD_SIZE; |
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uint8_t nonce[12]; |
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memset (nonce, 0, 12); |
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nonce[4] = recordIndex; // nonce is record index |
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if (!DecryptECIES (replyKey, nonce, record, SHORT_TUNNEL_BUILD_RECORD_SIZE, record)) |
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{ |
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LogPrint (eLogWarning, "Tunnel: Response AEAD decryption failed"); |
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return false; |
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} |
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return true; |
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} |
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void ShortECIESTunnelHopConfig::DecryptRecord (uint8_t * records, int index) const |
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{ |
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uint8_t * record = records + index*SHORT_TUNNEL_BUILD_RECORD_SIZE; |
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uint8_t nonce[12]; |
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memset (nonce, 0, 12); |
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nonce[4] = index; // nonce is index |
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i2p::crypto::ChaCha20 (record, SHORT_TUNNEL_BUILD_RECORD_SIZE, replyKey, nonce, record); |
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} |
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uint64_t ShortECIESTunnelHopConfig::GetGarlicKey (uint8_t * key) const |
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{ |
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uint64_t tag; |
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memcpy (&tag, m_CK, 8); |
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memcpy (key, m_CK + 32, 32); |
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return tag; |
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} |
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void TunnelConfig::CreatePeers (const std::vector<std::shared_ptr<const i2p::data::IdentityEx> >& peers) |
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{ |
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TunnelHopConfig * prev = nullptr; |
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for (const auto& it: peers) |
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{ |
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TunnelHopConfig * hop = nullptr; |
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if (m_IsShort) |
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hop = new ShortECIESTunnelHopConfig (it); |
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else |
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{ |
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if (it->GetCryptoKeyType () == i2p::data::CRYPTO_KEY_TYPE_ECIES_X25519_AEAD) |
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hop = new LongECIESTunnelHopConfig (it); |
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else |
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LogPrint (eLogError, "Tunnel: ElGamal router is not supported"); |
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} |
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if (hop) |
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{ |
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if (prev) |
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prev->SetNext (hop); |
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else |
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m_FirstHop = hop; |
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prev = hop; |
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} |
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} |
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m_LastHop = prev; |
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} |
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} |
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} |