/* * Copyright (c)2013-2020 ZeroTier, Inc. * * Use of this software is governed by the Business Source License included * in the LICENSE.TXT file in the project's root directory. * * Change Date: 2024-01-01 * * On the date above, in accordance with the Business Source License, use * of this software will be governed by version 2.0 of the Apache License. */ /****/ #include "Constants.hpp" #include "RuntimeEnvironment.hpp" #include "Trace.hpp" #include "Peer.hpp" #include "Topology.hpp" #include "SelfAwareness.hpp" #include "InetAddress.hpp" #include "Protocol.hpp" #include "Endpoint.hpp" #include "Expect.hpp" namespace ZeroTier { Peer::Peer(const RuntimeEnvironment *renv) : RR(renv), m_ephemeralPairTimestamp(0), m_lastReceive(0), m_lastSend(0), m_lastSentHello(), m_lastWhoisRequestReceived(0), m_lastEchoRequestReceived(0), m_lastPrioritizedPaths(0), m_lastProbeReceived(0), m_alivePathCount(0), m_tryQueue(), m_tryQueuePtr(m_tryQueue.end()), m_vProto(0), m_vMajor(0), m_vMinor(0), m_vRevision(0) { } Peer::~Peer() { Utils::burn(m_helloMacKey,sizeof(m_helloMacKey)); } bool Peer::init(const Identity &peerIdentity) { RWMutex::Lock l(m_lock); if (m_id) // already initialized sanity check return false; m_id = peerIdentity; uint8_t k[ZT_SYMMETRIC_KEY_SIZE]; if (!RR->identity.agree(peerIdentity,k)) return false; m_identityKey.set(new SymmetricKey(RR->node->now(),k)); Utils::burn(k,sizeof(k)); m_deriveSecondaryIdentityKeys(); return true; } void Peer::received( void *tPtr, const SharedPtr &path, const unsigned int hops, const uint64_t packetId, const unsigned int payloadLength, const Protocol::Verb verb, const Protocol::Verb inReVerb) { const int64_t now = RR->node->now(); m_lastReceive = now; m_inMeter.log(now,payloadLength); if (hops == 0) { RWMutex::RMaybeWLock l(m_lock); // If this matches an existing path, skip path learning stuff. For the small number // of paths a peer will have linear scan is the fastest way to do lookup. for (unsigned int i=0;i < m_alivePathCount;++i) { if (m_paths[i] == path) return; } // If we made it here, we don't already know this path. if (RR->node->shouldUsePathForZeroTierTraffic(tPtr, m_id, path->localSocket(), path->address())) { // SECURITY: note that if we've made it here we expected this OK, see Expect.hpp. // There is replay protection in effect for OK responses. if (verb == Protocol::VERB_OK) { // If we're learning a new path convert the lock to an exclusive write lock. l.writing(); // If the path list is full, replace the least recently active path. Otherwise append new path. unsigned int newPathIdx = 0; if (m_alivePathCount == ZT_MAX_PEER_NETWORK_PATHS) { int64_t lastReceiveTimeMax = 0; for (unsigned int i=0;iaddress().family() == path->address().family()) && (m_paths[i]->localSocket() == path->localSocket()) && // TODO: should be localInterface when multipath is integrated (m_paths[i]->address().ipsEqual2(path->address()))) { // Replace older path if everything is the same except the port number, since NAT/firewall reboots // and other wacky stuff can change port number assignments. m_paths[i] = path; return; } else if (m_paths[i]->lastIn() >= lastReceiveTimeMax) { lastReceiveTimeMax = m_paths[i]->lastIn(); newPathIdx = i; } } } else { newPathIdx = m_alivePathCount++; } InetAddress old; if (m_paths[newPathIdx]) old = m_paths[newPathIdx]->address(); m_paths[newPathIdx] = path; // Re-prioritize paths to include the new one. m_prioritizePaths(now); // Remember most recently learned paths for future bootstrap attempts on restart. Endpoint pathEndpoint(path->address()); m_bootstrap[pathEndpoint.type()] = pathEndpoint; RR->t->learnedNewPath(tPtr, 0x582fabdd, packetId, m_id, path->address(), old); } else { path->sent(now,hello(tPtr,path->localSocket(),path->address(),now)); RR->t->tryingNewPath(tPtr, 0xb7747ddd, m_id, path->address(), path->address(), packetId, (uint8_t)verb, m_id); } } } } unsigned int Peer::hello(void *tPtr,int64_t localSocket,const InetAddress &atAddress,int64_t now) { Buf outp; const int64_t now = RR->node->now(); const uint64_t packetId = m_identityKey->nextMessage(RR->identity.address(),m_id.address()); int ii = Protocol::newPacket(outp,packetId,m_id.address(),RR->identity.address(),Protocol::VERB_HELLO); outp.wI8(ii,ZT_PROTO_VERSION); outp.wI8(ii,ZEROTIER_VERSION_MAJOR); outp.wI8(ii,ZEROTIER_VERSION_MINOR); outp.wI16(ii,ZEROTIER_VERSION_REVISION); outp.wI64(ii,(uint64_t)now); outp.wO(ii,RR->identity); outp.wO(ii,atAddress); const int ivStart = ii; outp.wR(ii,12); // LEGACY: the six reserved bytes after the IV exist for legacy compatibility with v1.x nodes. // Once those are dead they'll become just reserved bytes for future use as flags etc. outp.wI32(ii,0); // reserved bytes void *const legacyMoonCountStart = outp.unsafeData + ii; outp.wI16(ii,0); const uint64_t legacySalsaIv = packetId & ZT_CONST_TO_BE_UINT64(0xfffffffffffffff8ULL); Salsa20(m_identityKey->secret,&legacySalsaIv).crypt12(legacyMoonCountStart,legacyMoonCountStart,2); const int cryptSectionStart = ii; FCV md; Dictionary::append(md,ZT_PROTO_HELLO_NODE_META_INSTANCE_ID,RR->instanceId); outp.wI16(ii,(uint16_t)md.size()); outp.wB(ii,md.data(),(unsigned int)md.size()); if (unlikely((ii + ZT_HMACSHA384_LEN) > ZT_BUF_SIZE)) // sanity check: should be impossible return 0; AES::CTR ctr(m_helloCipher); void *const cryptSection = outp.unsafeData + ii; ctr.init(outp.unsafeData + ivStart,0,cryptSection); ctr.crypt(cryptSection,ii - cryptSectionStart); ctr.finish(); HMACSHA384(m_helloMacKey,outp.unsafeData,ii,outp.unsafeData + ii); ii += ZT_HMACSHA384_LEN; // LEGACY: we also need Poly1305 for v1.x peers. uint8_t polyKey[ZT_POLY1305_KEY_SIZE],perPacketKey[ZT_SALSA20_KEY_SIZE]; Protocol::salsa2012DeriveKey(m_identityKey->secret,perPacketKey,outp,ii); Salsa20(perPacketKey,&packetId).crypt12(Utils::ZERO256,polyKey,sizeof(polyKey)); Poly1305 p1305(polyKey); p1305.update(outp.unsafeData + ZT_PROTO_PACKET_ENCRYPTED_SECTION_START,ii - ZT_PROTO_PACKET_ENCRYPTED_SECTION_START); uint64_t polyMac[2]; p1305.finish(polyMac); Utils::storeAsIsEndian(outp.unsafeData + ZT_PROTO_PACKET_MAC_INDEX,polyMac[0]); if (likely(RR->node->putPacket(tPtr,localSocket,atAddress,outp.unsafeData,ii))) return ii; return 0; } void Peer::pulse(void *const tPtr,const int64_t now,const bool isRoot) { RWMutex::Lock l(m_lock); // Determine if we need to send a full HELLO because we are refreshing ephemeral // keys or it's simply been too long. bool needHello = false; if ( (m_vProto >= 11) && ( ((now - m_ephemeralPairTimestamp) >= (ZT_SYMMETRIC_KEY_TTL / 2)) || ((m_ephemeralKeys[0])&&(m_ephemeralKeys[0]->odometer() >= (ZT_SYMMETRIC_KEY_TTL_MESSAGES / 2))) ) ) { m_ephemeralPair.generate(); needHello = true; } else if ((now - m_lastSentHello) >= ZT_PEER_HELLO_INTERVAL) { needHello = true; } // If we have no active paths and none queued to try, attempt any // old paths we have cached in m_bootstrap or that external code // supplies to the core via the optional API callback. if (m_tryQueue.empty()&&(m_alivePathCount == 0)) { InetAddress addr; if (RR->node->externalPathLookup(tPtr, m_id, -1, addr)) { if ((addr)&&(RR->node->shouldUsePathForZeroTierTraffic(tPtr, m_id, -1, addr))) { RR->t->tryingNewPath(tPtr, 0x84a10000, m_id, addr, InetAddress::NIL, 0, 0, Identity::NIL); sent(now,m_sendProbe(tPtr,-1,addr,nullptr,0,now)); } } if (!m_bootstrap.empty()) { unsigned int tryAtIndex = (unsigned int)Utils::random() % (unsigned int)m_bootstrap.size(); for(SortedMap< Endpoint::Type,Endpoint >::const_iterator i(m_bootstrap.begin());i != m_bootstrap.end();++i) { if (tryAtIndex > 0) { --tryAtIndex; } else { if ((i->second.isInetAddr())&&(!i->second.ip().ipsEqual(addr))) { RR->t->tryingNewPath(tPtr, 0x0a009444, m_id, i->second.ip(), InetAddress::NIL, 0, 0, Identity::NIL); sent(now,m_sendProbe(tPtr,-1,i->second.ip(),nullptr,0,now)); break; } } } } } // Sort paths and forget expired ones. m_prioritizePaths(now); // Attempt queued endpoints if they don't overlap with paths. if (!m_tryQueue.empty()) { for(int k=0;kts) < ZT_PATH_ALIVE_TIMEOUT)) { if (m_tryQueuePtr->target.isInetAddr()) { for(unsigned int i=0;iaddress().ipsEqual(m_tryQueuePtr->target.ip())) goto skip_tryQueue_item; } if ((m_alivePathCount == 0) && (m_tryQueuePtr->breakSymmetricBFG1024) && (RR->node->natMustDie())) { // Attempt aggressive NAT traversal if both requested and enabled. This sends a probe // to all ports under 1024, which assumes that the peer has bound to such a port and // has attempted to initiate a connection through it. This can traverse a decent number // of symmetric NATs at the cost of 32KiB per attempt and the potential to trigger IDS // systems by looking like a port scan (because it is). uint16_t ports[1023]; for (unsigned int i=0;i<1023;++i) ports[i] = (uint64_t)(i + 1); for (unsigned int i=0;i<512;++i) { const uint64_t rn = Utils::random(); const unsigned int a = (unsigned int)rn % 1023; const unsigned int b = (unsigned int)(rn >> 32U) % 1023; if (a != b) { const uint16_t tmp = ports[a]; ports[a] = ports[b]; ports[b] = tmp; } } sent(now,m_sendProbe(tPtr, -1, m_tryQueuePtr->target.ip(), ports, 1023, now)); } else { sent(now,m_sendProbe(tPtr, -1, m_tryQueuePtr->target.ip(), nullptr, 0, now)); } } } skip_tryQueue_item: m_tryQueue.erase(m_tryQueuePtr++); } } // Do keepalive on all currently active paths, sending HELLO to the first // if needHello is true and sending small keepalives to others. uint64_t randomJunk = Utils::random(); for(unsigned int i=0;ilocalSocket(), m_paths[i]->address(), now); m_paths[i]->sent(now, bytes); sent(now,bytes); m_lastSentHello = now; } else if ((now - m_paths[i]->lastOut()) >= ZT_PATH_KEEPALIVE_PERIOD) { m_paths[i]->send(RR, tPtr, reinterpret_cast(&randomJunk) + (i & 7U), 1, now); sent(now,1); } } // Send a HELLO indirectly if we were not able to send one via any direct path. if (needHello) { const SharedPtr root(RR->topology->root()); if (root) { const SharedPtr via(root->path(now)); if (via) { const unsigned int bytes = hello(tPtr,via->localSocket(),via->address(),now); via->sent(now,bytes); root->relayed(now,bytes); sent(now,bytes); m_lastSentHello = now; } } } } void Peer::contact(void *tPtr,const int64_t now,const Endpoint &ep,const bool breakSymmetricBFG1024) { static uint8_t foo = 0; RWMutex::Lock l(m_lock); if (ep.isInetAddr()&&ep.ip().isV4()) { // For IPv4 addresses we send a tiny packet with a low TTL, which helps to // traverse some NAT types. It has no effect otherwise. It's important to // send this right away in case this is a coordinated attempt via RENDEZVOUS. RR->node->putPacket(tPtr,-1,ep.ip(),&foo,1,2); ++foo; } const bool wasEmpty = m_tryQueue.empty(); if (!wasEmpty) { for(List::iterator i(m_tryQueue.begin());i!=m_tryQueue.end();++i) { if (i->target == ep) { i->ts = now; i->breakSymmetricBFG1024 = breakSymmetricBFG1024; return; } } } #ifdef __CPP11__ m_tryQueue.emplace_back(now, ep, breakSymmetricBFG1024); #else _tryQueue.push_back(_TryQueueItem(now,ep,breakSymmetricBFG1024)); #endif if (wasEmpty) m_tryQueuePtr = m_tryQueue.begin(); } void Peer::resetWithinScope(void *tPtr,InetAddress::IpScope scope,int inetAddressFamily,int64_t now) { RWMutex::Lock l(m_lock); unsigned int pc = 0; for(unsigned int i=0;iaddress().family() == inetAddressFamily) && (m_paths[i]->address().ipScope() == scope))) { const unsigned int bytes = m_sendProbe(tPtr, m_paths[i]->localSocket(), m_paths[i]->address(), nullptr, 0, now); m_paths[i]->sent(now, bytes); sent(now,bytes); } else if (pc != i) { m_paths[pc++] = m_paths[i]; } } m_alivePathCount = pc; while (pc < ZT_MAX_PEER_NETWORK_PATHS) m_paths[pc].zero(); } bool Peer::directlyConnected(int64_t now) { if ((now - m_lastPrioritizedPaths) > ZT_PEER_PRIORITIZE_PATHS_INTERVAL) { RWMutex::Lock l(m_lock); m_prioritizePaths(now); return m_alivePathCount > 0; } else { RWMutex::RLock l(m_lock); return m_alivePathCount > 0; } } void Peer::getAllPaths(Vector< SharedPtr > &paths) { RWMutex::RLock l(m_lock); paths.clear(); paths.reserve(m_alivePathCount); paths.assign(m_paths, m_paths + m_alivePathCount); } void Peer::save(void *tPtr) const { uint8_t buf[8 + ZT_PEER_MARSHAL_SIZE_MAX]; // Prefix each saved peer with the current timestamp. Utils::storeBigEndian(buf,(uint64_t)RR->node->now()); const int len = marshal(buf + 8); if (len > 0) { uint64_t id[2]; id[0] = m_id.address().toInt(); id[1] = 0; RR->node->stateObjectPut(tPtr,ZT_STATE_OBJECT_PEER,id,buf,(unsigned int)len + 8); } } int Peer::marshal(uint8_t data[ZT_PEER_MARSHAL_SIZE_MAX]) const noexcept { RWMutex::RLock l(m_lock); if (!m_identityKey) return -1; data[0] = 0; // serialized peer version // Include our identity's address to detect if this changes and require // recomputation of m_identityKey. RR->identity.address().copyTo(data + 1); // SECURITY: encryption in place is only to protect secrets if they are // cached to local storage. It's not used over the wire. Dumb ECB is fine // because secret keys are random and have no structure to reveal. RR->localCacheSymmetric.encrypt(m_identityKey->secret,data + 6); RR->localCacheSymmetric.encrypt(m_identityKey->secret + 22,data + 17); RR->localCacheSymmetric.encrypt(m_identityKey->secret + 38,data + 33); int p = 54; int s = m_id.marshal(data + p, false); if (s < 0) return -1; p += s; s = m_locator.marshal(data + p); if (s <= 0) return s; p += s; data[p++] = (uint8_t)m_bootstrap.size(); for(std::map< Endpoint::Type,Endpoint >::const_iterator i(m_bootstrap.begin());i != m_bootstrap.end();++i) { // NOLINT(modernize-loop-convert,hicpp-use-auto,modernize-use-auto) s = i->second.marshal(data + p); if (s <= 0) return -1; p += s; } Utils::storeBigEndian(data + p,(uint16_t)m_vProto); p += 2; Utils::storeBigEndian(data + p,(uint16_t)m_vMajor); p += 2; Utils::storeBigEndian(data + p,(uint16_t)m_vMinor); p += 2; Utils::storeBigEndian(data + p,(uint16_t)m_vRevision); p += 2; data[p++] = 0; data[p++] = 0; return p; } int Peer::unmarshal(const uint8_t *restrict data,const int len) noexcept { RWMutex::Lock l(m_lock); if ((len <= 54) || (data[0] != 0)) return -1; m_identityKey.zero(); m_ephemeralKeys[0].zero(); m_ephemeralKeys[1].zero(); if (Address(data + 1) == RR->identity.address()) { uint8_t k[ZT_SYMMETRIC_KEY_SIZE]; static_assert(ZT_SYMMETRIC_KEY_SIZE == 48,"marshal() and unmarshal() must be revisited if ZT_SYMMETRIC_KEY_SIZE is changed"); RR->localCacheSymmetric.decrypt(data + 1,k); RR->localCacheSymmetric.decrypt(data + 17,k + 16); RR->localCacheSymmetric.decrypt(data + 33,k + 32); m_identityKey.set(new SymmetricKey(RR->node->now(),k)); Utils::burn(k,sizeof(k)); } int p = 49; int s = m_id.unmarshal(data + 38, len - 38); if (s < 0) return s; p += s; if (!m_identityKey) { uint8_t k[ZT_SYMMETRIC_KEY_SIZE]; if (!RR->identity.agree(m_id,k)) return -1; m_identityKey.set(new SymmetricKey(RR->node->now(),k)); Utils::burn(k,sizeof(k)); } s = m_locator.unmarshal(data + p, len - p); if (s < 0) return s; p += s; if (p >= len) return -1; const unsigned int bootstrapCount = data[p++]; if (bootstrapCount > ZT_MAX_PEER_NETWORK_PATHS) return -1; m_bootstrap.clear(); for(unsigned int i=0;i len) return -1; m_vProto = Utils::loadBigEndian(data + p); p += 2; m_vMajor = Utils::loadBigEndian(data + p); p += 2; m_vMinor = Utils::loadBigEndian(data + p); p += 2; m_vRevision = Utils::loadBigEndian(data + p); p += 2; p += 2 + (int)Utils::loadBigEndian(data + p); m_deriveSecondaryIdentityKeys(); return (p > len) ? -1 : p; } struct _PathPriorityComparisonOperator { ZT_INLINE bool operator()(const SharedPtr &a,const SharedPtr &b) const noexcept { // Sort in descending order of most recent receive time. return (a->lastIn() > b->lastIn()); } }; void Peer::m_prioritizePaths(int64_t now) { // assumes _lock is locked for writing m_lastPrioritizedPaths = now; if (m_alivePathCount > 0) { // Sort paths in descending order of priority. std::sort(m_paths, m_paths + m_alivePathCount, _PathPriorityComparisonOperator()); // Let go of paths that have expired. for (unsigned int i = 0;ialive(now))) { m_alivePathCount = i; for (;i < ZT_MAX_PEER_NETWORK_PATHS;++i) m_paths[i].zero(); break; } } } } unsigned int Peer::m_sendProbe(void *tPtr,int64_t localSocket,const InetAddress &atAddress,const uint16_t *ports,const unsigned int numPorts,int64_t now) { // Assumes m_lock is locked const SharedPtr k(m_key()); const uint64_t packetId = k->nextMessage(RR->identity.address(),m_id.address()); uint8_t p[ZT_PROTO_MIN_PACKET_LENGTH + 1]; Utils::storeAsIsEndian(p + ZT_PROTO_PACKET_ID_INDEX,packetId); m_id.address().copyTo(p + ZT_PROTO_PACKET_DESTINATION_INDEX); RR->identity.address().copyTo(p + ZT_PROTO_PACKET_SOURCE_INDEX); p[ZT_PROTO_PACKET_FLAGS_INDEX] = 0; p[ZT_PROTO_PACKET_VERB_INDEX] = Protocol::VERB_ECHO; p[ZT_PROTO_PACKET_VERB_INDEX + 1] = 0; // arbitrary payload Protocol::armor(p,ZT_PROTO_MIN_PACKET_LENGTH + 1,k,cipher()); RR->expect->sending(packetId,now); if (numPorts > 0) { InetAddress tmp(atAddress); for(unsigned int i=0;inode->putPacket(tPtr,-1,tmp,p,ZT_PROTO_MIN_PACKET_LENGTH + 1); } return ZT_PROTO_MIN_PACKET_LENGTH * numPorts; } else { RR->node->putPacket(tPtr,-1,atAddress,p,ZT_PROTO_MIN_PACKET_LENGTH + 1); return ZT_PROTO_MIN_PACKET_LENGTH; } } void Peer::m_deriveSecondaryIdentityKeys() noexcept { uint8_t hk[ZT_SYMMETRIC_KEY_SIZE]; KBKDFHMACSHA384(m_identityKey->secret,ZT_KBKDF_LABEL_HELLO_DICTIONARY_ENCRYPT,0,0,hk); m_helloCipher.init(hk); Utils::burn(hk,sizeof(hk)); KBKDFHMACSHA384(m_identityKey->secret,ZT_KBKDF_LABEL_PACKET_HMAC,0,0,m_helloMacKey); } } // namespace ZeroTier