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252 lines
9.4 KiB
252 lines
9.4 KiB
/*
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This file is part of cpp-ethereum.
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cpp-ethereum is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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cpp-ethereum is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with cpp-ethereum. If not, see <http://www.gnu.org/licenses/>.
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*/
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/** @file RLPXFrameCoder.cpp
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* @author Alex Leverington <nessence@gmail.com>
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* @date 2015
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*/
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#include "RLPXFrameCoder.h"
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#include <libdevcore/Assertions.h>
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#include "RLPxHandshake.h"
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#include "RLPXPacket.h"
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using namespace std;
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using namespace dev;
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using namespace dev::p2p;
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using namespace CryptoPP;
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RLPXFrameInfo::RLPXFrameInfo(bytesConstRef _header):
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length((_header[0] * 256 + _header[1]) * 256 + _header[2]),
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padding((16 - (length % 16)) % 16),
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data(_header.cropped(3).toBytes()),
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header(RLP(data, RLP::ThrowOnFail | RLP::FailIfTooSmall)),
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protocolId(header[0].toInt<uint16_t>()),
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multiFrame(header.itemCount() > 1),
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sequenceId(multiFrame ? header[1].toInt<uint16_t>() : 0),
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totalLength(header.itemCount() == 3 ? header[2].toInt<uint32_t>() : 0)
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{}
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RLPXFrameCoder::RLPXFrameCoder(RLPXHandshake const& _init)
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{
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setup(_init.m_originated, _init.m_remoteEphemeral, _init.m_remoteNonce, _init.m_ecdhe, _init.m_nonce, &_init.m_ackCipher, &_init.m_authCipher);
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}
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RLPXFrameCoder::RLPXFrameCoder(bool _originated, h512 const& _remoteEphemeral, h256 const& _remoteNonce, crypto::ECDHE const& _ecdhe, h256 const& _nonce, bytesConstRef _ackCipher, bytesConstRef _authCipher)
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{
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setup(_originated, _remoteEphemeral, _remoteNonce, _ecdhe, _nonce, _ackCipher, _authCipher);
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}
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void RLPXFrameCoder::setup(bool _originated, h512 const& _remoteEphemeral, h256 const& _remoteNonce, crypto::ECDHE const& _ecdhe, h256 const& _nonce, bytesConstRef _ackCipher, bytesConstRef _authCipher)
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{
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bytes keyMaterialBytes(64);
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bytesRef keyMaterial(&keyMaterialBytes);
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// shared-secret = sha3(ecdhe-shared-secret || sha3(nonce || initiator-nonce))
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Secret ephemeralShared;
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_ecdhe.agree(_remoteEphemeral, ephemeralShared);
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ephemeralShared.ref().copyTo(keyMaterial.cropped(0, h256::size));
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h512 nonceMaterial;
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h256 const& leftNonce = _originated ? _remoteNonce : _nonce;
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h256 const& rightNonce = _originated ? _nonce : _remoteNonce;
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leftNonce.ref().copyTo(nonceMaterial.ref().cropped(0, h256::size));
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rightNonce.ref().copyTo(nonceMaterial.ref().cropped(h256::size, h256::size));
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auto outRef(keyMaterial.cropped(h256::size, h256::size));
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sha3(nonceMaterial.ref(), outRef); // output h(nonces)
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sha3(keyMaterial, outRef); // output shared-secret
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// token: sha3(outRef, bytesRef(&token)); -> m_host (to be saved to disk)
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// aes-secret = sha3(ecdhe-shared-secret || shared-secret)
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sha3(keyMaterial, outRef); // output aes-secret
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m_frameEncKey.resize(h256::size);
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memcpy(m_frameEncKey.data(), outRef.data(), h256::size);
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m_frameDecKey.resize(h256::size);
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memcpy(m_frameDecKey.data(), outRef.data(), h256::size);
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h128 iv;
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m_frameEnc.SetKeyWithIV(m_frameEncKey, h256::size, iv.data());
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m_frameDec.SetKeyWithIV(m_frameDecKey, h256::size, iv.data());
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// mac-secret = sha3(ecdhe-shared-secret || aes-secret)
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sha3(keyMaterial, outRef); // output mac-secret
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m_macEncKey.resize(h256::size);
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memcpy(m_macEncKey.data(), outRef.data(), h256::size);
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m_macEnc.SetKey(m_macEncKey, h256::size);
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// Initiator egress-mac: sha3(mac-secret^recipient-nonce || auth-sent-init)
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// ingress-mac: sha3(mac-secret^initiator-nonce || auth-recvd-ack)
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// Recipient egress-mac: sha3(mac-secret^initiator-nonce || auth-sent-ack)
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// ingress-mac: sha3(mac-secret^recipient-nonce || auth-recvd-init)
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(*(h256*)outRef.data() ^ _remoteNonce).ref().copyTo(keyMaterial);
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bytesConstRef egressCipher = _originated ? _authCipher : _ackCipher;
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keyMaterialBytes.resize(h256::size + egressCipher.size());
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keyMaterial.retarget(keyMaterialBytes.data(), keyMaterialBytes.size());
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egressCipher.copyTo(keyMaterial.cropped(h256::size, egressCipher.size()));
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m_egressMac.Update(keyMaterial.data(), keyMaterial.size());
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// recover mac-secret by re-xoring remoteNonce
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(*(h256*)keyMaterial.data() ^ _remoteNonce ^ _nonce).ref().copyTo(keyMaterial);
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bytesConstRef ingressCipher = _originated ? _ackCipher : _authCipher;
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keyMaterialBytes.resize(h256::size + ingressCipher.size());
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keyMaterial.retarget(keyMaterialBytes.data(), keyMaterialBytes.size());
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ingressCipher.copyTo(keyMaterial.cropped(h256::size, ingressCipher.size()));
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m_ingressMac.Update(keyMaterial.data(), keyMaterial.size());
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}
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void RLPXFrameCoder::writeFrame(uint16_t _protocolType, bytesConstRef _payload, bytes& o_bytes)
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{
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RLPStream header;
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uint32_t len = (uint32_t)_payload.size();
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header.appendRaw(bytes({byte((len >> 16) & 0xff), byte((len >> 8) & 0xff), byte(len & 0xff)}));
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header.appendList(1) << _protocolType;
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writeFrame(header, _payload, o_bytes);
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}
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void RLPXFrameCoder::writeFrame(uint16_t _protocolType, uint16_t _seqId, bytesConstRef _payload, bytes& o_bytes)
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{
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RLPStream header;
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uint32_t len = (uint32_t)_payload.size();
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header.appendRaw(bytes({byte((len >> 16) & 0xff), byte((len >> 8) & 0xff), byte(len & 0xff)}));
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header.appendList(2) << _protocolType << _seqId;
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writeFrame(header, _payload, o_bytes);
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}
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void RLPXFrameCoder::writeFrame(uint16_t _protocolType, uint16_t _seqId, uint32_t _totalSize, bytesConstRef _payload, bytes& o_bytes)
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{
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RLPStream header;
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uint32_t len = (uint32_t)_payload.size();
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header.appendRaw(bytes({byte((len >> 16) & 0xff), byte((len >> 8) & 0xff), byte(len & 0xff)}));
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header.appendList(3) << _protocolType << _seqId << _totalSize;
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writeFrame(header, _payload, o_bytes);
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}
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void RLPXFrameCoder::writeFrame(RLPStream const& _header, bytesConstRef _payload, bytes& o_bytes)
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{
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// TODO: SECURITY check header values && header <= 16 bytes
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bytes headerWithMac(h256::size);
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bytesConstRef(&_header.out()).copyTo(bytesRef(&headerWithMac));
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m_frameEnc.ProcessData(headerWithMac.data(), headerWithMac.data(), 16);
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updateEgressMACWithHeader(bytesConstRef(&headerWithMac).cropped(0, 16));
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egressDigest().ref().copyTo(bytesRef(&headerWithMac).cropped(h128::size,h128::size));
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auto padding = (16 - (_payload.size() % 16)) % 16;
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o_bytes.swap(headerWithMac);
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o_bytes.resize(32 + _payload.size() + padding + h128::size);
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bytesRef packetRef(o_bytes.data() + 32, _payload.size());
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m_frameEnc.ProcessData(packetRef.data(), _payload.data(), _payload.size());
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bytesRef paddingRef(o_bytes.data() + 32 + _payload.size(), padding);
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if (padding)
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m_frameEnc.ProcessData(paddingRef.data(), paddingRef.data(), padding);
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bytesRef packetWithPaddingRef(o_bytes.data() + 32, _payload.size() + padding);
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updateEgressMACWithFrame(packetWithPaddingRef);
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bytesRef macRef(o_bytes.data() + 32 + _payload.size() + padding, h128::size);
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egressDigest().ref().copyTo(macRef);
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}
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void RLPXFrameCoder::writeSingleFramePacket(bytesConstRef _packet, bytes& o_bytes)
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{
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RLPStream header;
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uint32_t len = (uint32_t)_packet.size();
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header.appendRaw(bytes({byte((len >> 16) & 0xff), byte((len >> 8) & 0xff), byte(len & 0xff)}));
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header.appendRaw(bytes({0xc2,0x80,0x80}));
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writeFrame(header, _packet, o_bytes);
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}
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bool RLPXFrameCoder::authAndDecryptHeader(bytesRef io)
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{
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asserts(io.size() == h256::size);
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updateIngressMACWithHeader(io);
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bytesConstRef macRef = io.cropped(h128::size, h128::size);
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h128 expected = ingressDigest();
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if (*(h128*)macRef.data() != expected)
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return false;
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m_frameDec.ProcessData(io.data(), io.data(), h128::size);
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return true;
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}
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bool RLPXFrameCoder::authAndDecryptFrame(bytesRef io)
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{
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bytesRef cipherText(io.cropped(0, io.size() - h128::size));
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updateIngressMACWithFrame(cipherText);
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bytesConstRef frameMac(io.data() + io.size() - h128::size, h128::size);
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if (*(h128*)frameMac.data() != ingressDigest())
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return false;
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m_frameDec.ProcessData(io.data(), io.data(), io.size() - h128::size);
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return true;
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}
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h128 RLPXFrameCoder::egressDigest()
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{
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SHA3_256 h(m_egressMac);
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h128 digest;
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h.TruncatedFinal(digest.data(), h128::size);
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return digest;
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}
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h128 RLPXFrameCoder::ingressDigest()
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{
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SHA3_256 h(m_ingressMac);
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h128 digest;
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h.TruncatedFinal(digest.data(), h128::size);
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return digest;
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}
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void RLPXFrameCoder::updateEgressMACWithHeader(bytesConstRef _headerCipher)
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{
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updateMAC(m_egressMac, _headerCipher.cropped(0, 16));
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}
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void RLPXFrameCoder::updateEgressMACWithFrame(bytesConstRef _cipher)
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{
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m_egressMac.Update(_cipher.data(), _cipher.size());
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updateMAC(m_egressMac);
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}
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void RLPXFrameCoder::updateIngressMACWithHeader(bytesConstRef _headerCipher)
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{
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updateMAC(m_ingressMac, _headerCipher.cropped(0, 16));
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}
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void RLPXFrameCoder::updateIngressMACWithFrame(bytesConstRef _cipher)
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{
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m_ingressMac.Update(_cipher.data(), _cipher.size());
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updateMAC(m_ingressMac);
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}
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void RLPXFrameCoder::updateMAC(SHA3_256& _mac, bytesConstRef _seed)
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{
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if (_seed.size() && _seed.size() != h128::size)
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asserts(false);
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SHA3_256 prevDigest(_mac);
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h128 encDigest(h128::size);
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prevDigest.TruncatedFinal(encDigest.data(), h128::size);
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h128 prevDigestOut = encDigest;
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{
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Guard l(x_macEnc);
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m_macEnc.ProcessData(encDigest.data(), encDigest.data(), 16);
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}
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if (_seed.size())
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encDigest ^= *(h128*)_seed.data();
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else
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encDigest ^= *(h128*)prevDigestOut.data();
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// update mac for final digest
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_mac.Update(encDigest.data(), h128::size);
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}
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