ZeroTierOne/node/CertificateOfMembership.cpp

/*
 * Copyright (c)2019 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: 2026-01-01
 *
 * 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 "CertificateOfMembership.hpp"

#include "ECC.hpp"
#include "Network.hpp"
#include "Node.hpp"
#include "RuntimeEnvironment.hpp"
#include "Switch.hpp"
#include "Topology.hpp"

namespace ZeroTier {

CertificateOfMembership::CertificateOfMembership(uint64_t timestamp, uint64_t timestampMaxDelta, uint64_t nwid, const Identity& issuedTo)
{
    _qualifiers[0].id = COM_RESERVED_ID_TIMESTAMP;
    _qualifiers[0].value = timestamp;
    _qualifiers[0].maxDelta = timestampMaxDelta;
    _qualifiers[1].id = COM_RESERVED_ID_NETWORK_ID;
    _qualifiers[1].value = nwid;
    _qualifiers[1].maxDelta = 0;
    _qualifiers[2].id = COM_RESERVED_ID_ISSUED_TO;
    _qualifiers[2].value = issuedTo.address().toInt();
    _qualifiers[2].maxDelta = 0xffffffffffffffffULL;

    // Include hash of full identity public key in COM for hardening purposes. Pack it in
    // using the original COM format. Format may be revised in the future to make this cleaner.
    uint64_t idHash[6];
    issuedTo.publicKeyHash(idHash);
    for (unsigned long i = 0; i < 4; ++i) {
        _qualifiers[i + 3].id = (uint64_t)(i + 3);
        _qualifiers[i + 3].value = Utils::ntoh(idHash[i]);
        _qualifiers[i + 3].maxDelta = 0xffffffffffffffffULL;
    }

    _qualifierCount = 7;
    memset(_signature.data, 0, ZT_ECC_SIGNATURE_LEN);
}

bool CertificateOfMembership::agreesWith(const CertificateOfMembership& other, const Identity& otherIdentity) const
{
    if ((_qualifierCount == 0) || (other._qualifierCount == 0)) {
        return false;
    }

    std::map<uint64_t, uint64_t> otherFields;
    for (unsigned int i = 0; i < other._qualifierCount; ++i) {
        otherFields[other._qualifiers[i].id] = other._qualifiers[i].value;
    }

    bool fullIdentityVerification = false;
    for (unsigned int i = 0; i < _qualifierCount; ++i) {
        const uint64_t qid = _qualifiers[i].id;
        if ((qid >= 3) && (qid <= 6)) {
            fullIdentityVerification = true;
        }
        std::map<uint64_t, uint64_t>::iterator otherQ(otherFields.find(qid));
        if (otherQ == otherFields.end()) {
            return false;
        }
        const uint64_t a = _qualifiers[i].value;
        const uint64_t b = otherQ->second;
        if (((a >= b) ? (a - b) : (b - a)) > _qualifiers[i].maxDelta) {
            return false;
        }
    }

    // If this COM has a full hash of its identity, assume the other must have this as well.
    // Otherwise we are on a controller that does not incorporate these.
    if (fullIdentityVerification) {
        uint64_t idHash[6];
        otherIdentity.publicKeyHash(idHash);
        for (unsigned long i = 0; i < 4; ++i) {
            std::map<uint64_t, uint64_t>::iterator otherQ(otherFields.find((uint64_t)(i + 3)));
            if (otherQ == otherFields.end()) {
                return false;
            }
            if (otherQ->second != Utils::ntoh(idHash[i])) {
                return false;
            }
        }
    }

    return true;
}

bool CertificateOfMembership::sign(const Identity& with)
{
    uint64_t buf[ZT_NETWORK_COM_MAX_QUALIFIERS * 3];
    unsigned int ptr = 0;
    for (unsigned int i = 0; i < _qualifierCount; ++i) {
        buf[ptr++] = Utils::hton(_qualifiers[i].id);
        buf[ptr++] = Utils::hton(_qualifiers[i].value);
        buf[ptr++] = Utils::hton(_qualifiers[i].maxDelta);
    }

    try {
        _signature = with.sign(buf, ptr * sizeof(uint64_t));
        _signedBy = with.address();
        return true;
    }
    catch (...) {
        _signedBy.zero();
        return false;
    }
}

int CertificateOfMembership::verify(const RuntimeEnvironment* RR, void* tPtr) const
{
    if ((! _signedBy) || (_signedBy != Network::controllerFor(networkId())) || (_qualifierCount > ZT_NETWORK_COM_MAX_QUALIFIERS)) {
        return -1;
    }

    const Identity id(RR->topology->getIdentity(tPtr, _signedBy));
    if (! id) {
        RR->sw->requestWhois(tPtr, RR->node->now(), _signedBy);
        return 1;
    }

    uint64_t buf[ZT_NETWORK_COM_MAX_QUALIFIERS * 3];
    unsigned int ptr = 0;
    for (unsigned int i = 0; i < _qualifierCount; ++i) {
        buf[ptr++] = Utils::hton(_qualifiers[i].id);
        buf[ptr++] = Utils::hton(_qualifiers[i].value);
        buf[ptr++] = Utils::hton(_qualifiers[i].maxDelta);
    }
    return (id.verify(buf, ptr * sizeof(uint64_t), _signature) ? 0 : -1);
}

}   // namespace ZeroTier