/*
 * 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 "../node/Constants.hpp"
#include "../version.h"

#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifdef __WINDOWS__
#include <iphlpapi.h>
#include <netioapi.h>
#include <shlobj.h>
#include <windows.h>
#include <winsock2.h>
#else
#include <ifaddrs.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#endif

#include "../node/Buffer.hpp"
#include "../node/Node.hpp"
#include "../node/SHA512.hpp"
#include "../node/Utils.hpp"
#include "../osdep/OSUtils.hpp"
#include "SoftwareUpdater.hpp"

namespace ZeroTier {

static int _compareVersion(unsigned int maj1, unsigned int min1, unsigned int rev1, unsigned int b1, unsigned int maj2, unsigned int min2, unsigned int rev2, unsigned int b2)
{
    if (maj1 > maj2) {
        return 1;
    }
    else if (maj1 < maj2) {
        return -1;
    }
    else {
        if (min1 > min2) {
            return 1;
        }
        else if (min1 < min2) {
            return -1;
        }
        else {
            if (rev1 > rev2) {
                return 1;
            }
            else if (rev1 < rev2) {
                return -1;
            }
            else {
                if (b1 > b2) {
                    return 1;
                }
                else if (b1 < b2) {
                    return -1;
                }
                else {
                    return 0;
                }
            }
        }
    }
}

SoftwareUpdater::SoftwareUpdater(Node& node, const std::string& homePath) : _node(node), _lastCheckTime(0), _homePath(homePath), _channel(ZT_SOFTWARE_UPDATE_DEFAULT_CHANNEL), _distLog((FILE*)0), _latestValid(false), _downloadLength(0)
{
    OSUtils::rm((_homePath + ZT_PATH_SEPARATOR_S ZT_SOFTWARE_UPDATE_BIN_FILENAME).c_str());
}

SoftwareUpdater::~SoftwareUpdater()
{
    if (_distLog)
        fclose(_distLog);
}

void SoftwareUpdater::setUpdateDistribution(bool distribute)
{
    _dist.clear();
    if (distribute) {
        _distLog = fopen((_homePath + ZT_PATH_SEPARATOR_S "update-dist.log").c_str(), "a");

        const std::string udd(_homePath + ZT_PATH_SEPARATOR_S "update-dist.d");
        const std::vector<std::string> ud(OSUtils::listDirectory(udd.c_str()));
        for (std::vector<std::string>::const_iterator u(ud.begin()); u != ud.end(); ++u) {
            // Each update has a companion .json file describing it. Other files are ignored.
            if ((u->length() > 5) && (u->substr(u->length() - 5, 5) == ".json")) {
                std::string buf;
                if (OSUtils::readFile((udd + ZT_PATH_SEPARATOR_S + *u).c_str(), buf)) {
                    try {
                        _D d;
                        d.meta = OSUtils::jsonParse(buf);   // throws on invalid JSON

                        // If update meta is called e.g. foo.exe.json, then foo.exe is the update itself
                        const std::string binPath(udd + ZT_PATH_SEPARATOR_S + u->substr(0, u->length() - 5));
                        const std::string metaHash(OSUtils::jsonBinFromHex(d.meta[ZT_SOFTWARE_UPDATE_JSON_UPDATE_HASH]));
                        if ((metaHash.length() == 64) && (OSUtils::readFile(binPath.c_str(), d.bin))) {
                            std::array<uint8_t, 64> sha512;
                            SHA512(sha512.data(), d.bin.data(), (unsigned int)d.bin.length());
                            if (! memcmp(sha512.data(), metaHash.data(), 64)) {                 // double check that hash in JSON is correct
                                d.meta[ZT_SOFTWARE_UPDATE_JSON_UPDATE_SIZE] = d.bin.length();   // override with correct value -- setting this in meta json is optional
                                std::array<uint8_t, 16> shakey;
                                memcpy(shakey.data(), sha512.data(), 16);
                                _dist[shakey] = d;
                                if (_distLog) {
                                    fprintf(_distLog, ".......... INIT: DISTRIBUTING %s (%u bytes)" ZT_EOL_S, binPath.c_str(), (unsigned int)d.bin.length());
                                    fflush(_distLog);
                                }
                            }
                        }
                    }
                    catch (...) {
                    }   // ignore bad meta JSON, etc.
                }
            }
        }
    }
    else {
        if (_distLog) {
            fclose(_distLog);
            _distLog = (FILE*)0;
        }
    }
}

void SoftwareUpdater::handleSoftwareUpdateUserMessage(uint64_t origin, const void* data, unsigned int len)
{
    if (! len)
        return;
    const MessageVerb v = (MessageVerb) reinterpret_cast<const uint8_t*>(data)[0];
    try {
        switch (v) {
            case VERB_GET_LATEST:
            case VERB_LATEST: {
                nlohmann::json req = OSUtils::jsonParse(std::string(reinterpret_cast<const char*>(data) + 1, len - 1));   // throws on invalid JSON
                if (req.is_object()) {
                    const unsigned int rvMaj = (unsigned int)OSUtils::jsonInt(req[ZT_SOFTWARE_UPDATE_JSON_VERSION_MAJOR], 0);
                    const unsigned int rvMin = (unsigned int)OSUtils::jsonInt(req[ZT_SOFTWARE_UPDATE_JSON_VERSION_MINOR], 0);
                    const unsigned int rvRev = (unsigned int)OSUtils::jsonInt(req[ZT_SOFTWARE_UPDATE_JSON_VERSION_REVISION], 0);
                    const unsigned int rvBld = (unsigned int)OSUtils::jsonInt(req[ZT_SOFTWARE_UPDATE_JSON_VERSION_BUILD], 0);
                    const unsigned int rvPlatform = (unsigned int)OSUtils::jsonInt(req[ZT_SOFTWARE_UPDATE_JSON_PLATFORM], 0);
                    const unsigned int rvArch = (unsigned int)OSUtils::jsonInt(req[ZT_SOFTWARE_UPDATE_JSON_ARCHITECTURE], 0);
                    const unsigned int rvVendor = (unsigned int)OSUtils::jsonInt(req[ZT_SOFTWARE_UPDATE_JSON_VENDOR], 0);
                    const std::string rvChannel(OSUtils::jsonString(req[ZT_SOFTWARE_UPDATE_JSON_CHANNEL], ""));

                    if (v == VERB_GET_LATEST) {
                        if (! _dist.empty()) {
                            const nlohmann::json* latest = (const nlohmann::json*)0;
                            const std::string expectedSigner = OSUtils::jsonString(req[ZT_SOFTWARE_UPDATE_JSON_EXPECT_SIGNED_BY], "");
                            unsigned int bestVMaj = rvMaj;
                            unsigned int bestVMin = rvMin;
                            unsigned int bestVRev = rvRev;
                            unsigned int bestVBld = rvBld;
                            for (std::map<std::array<uint8_t, 16>, _D>::const_iterator d(_dist.begin()); d != _dist.end(); ++d) {
                                // The arch field in update description .json files can be an array for e.g. multi-arch update files
                                const nlohmann::json& dvArch2 = d->second.meta[ZT_SOFTWARE_UPDATE_JSON_ARCHITECTURE];
                                std::vector<unsigned int> dvArch;
                                if (dvArch2.is_array()) {
                                    for (unsigned long i = 0; i < dvArch2.size(); ++i)
                                        dvArch.push_back((unsigned int)OSUtils::jsonInt(dvArch2[i], 0));
                                }
                                else {
                                    dvArch.push_back((unsigned int)OSUtils::jsonInt(dvArch2, 0));
                                }

                                if ((OSUtils::jsonInt(d->second.meta[ZT_SOFTWARE_UPDATE_JSON_PLATFORM], 0) == rvPlatform) && (std::find(dvArch.begin(), dvArch.end(), rvArch) != dvArch.end())
                                    && (OSUtils::jsonInt(d->second.meta[ZT_SOFTWARE_UPDATE_JSON_VENDOR], 0) == rvVendor) && (OSUtils::jsonString(d->second.meta[ZT_SOFTWARE_UPDATE_JSON_CHANNEL], "") == rvChannel)
                                    && (OSUtils::jsonString(d->second.meta[ZT_SOFTWARE_UPDATE_JSON_UPDATE_SIGNED_BY], "") == expectedSigner)) {
                                    const unsigned int dvMaj = (unsigned int)OSUtils::jsonInt(d->second.meta[ZT_SOFTWARE_UPDATE_JSON_VERSION_MAJOR], 0);
                                    const unsigned int dvMin = (unsigned int)OSUtils::jsonInt(d->second.meta[ZT_SOFTWARE_UPDATE_JSON_VERSION_MINOR], 0);
                                    const unsigned int dvRev = (unsigned int)OSUtils::jsonInt(d->second.meta[ZT_SOFTWARE_UPDATE_JSON_VERSION_REVISION], 0);
                                    const unsigned int dvBld = (unsigned int)OSUtils::jsonInt(d->second.meta[ZT_SOFTWARE_UPDATE_JSON_VERSION_BUILD], 0);
                                    if (_compareVersion(dvMaj, dvMin, dvRev, dvBld, bestVMaj, bestVMin, bestVRev, bestVBld) > 0) {
                                        latest = &(d->second.meta);
                                        bestVMaj = dvMaj;
                                        bestVMin = dvMin;
                                        bestVRev = dvRev;
                                        bestVBld = dvBld;
                                    }
                                }
                            }
                            if (latest) {
                                std::string lj;
                                lj.push_back((char)VERB_LATEST);
                                lj.append(OSUtils::jsonDump(*latest));
                                _node.sendUserMessage((void*)0, origin, ZT_SOFTWARE_UPDATE_USER_MESSAGE_TYPE, lj.data(), (unsigned int)lj.length());
                                if (_distLog) {
                                    fprintf(
                                        _distLog,
                                        "%.10llx GET_LATEST %u.%u.%u_%u platform %u arch %u vendor %u channel %s -> LATEST %u.%u.%u_%u" ZT_EOL_S,
                                        (unsigned long long)origin,
                                        rvMaj,
                                        rvMin,
                                        rvRev,
                                        rvBld,
                                        rvPlatform,
                                        rvArch,
                                        rvVendor,
                                        rvChannel.c_str(),
                                        bestVMaj,
                                        bestVMin,
                                        bestVRev,
                                        bestVBld);
                                    fflush(_distLog);
                                }
                            }
                        }   // else no reply, since we have nothing to distribute
                    }
                    else {   // VERB_LATEST

                        if ((origin == ZT_SOFTWARE_UPDATE_SERVICE) && (_compareVersion(rvMaj, rvMin, rvRev, rvBld, ZEROTIER_ONE_VERSION_MAJOR, ZEROTIER_ONE_VERSION_MINOR, ZEROTIER_ONE_VERSION_REVISION, ZEROTIER_ONE_VERSION_BUILD) > 0)
                            && (OSUtils::jsonString(req[ZT_SOFTWARE_UPDATE_JSON_UPDATE_SIGNED_BY], "") == ZT_SOFTWARE_UPDATE_SIGNING_AUTHORITY)) {
                            const unsigned long len = (unsigned long)OSUtils::jsonInt(req[ZT_SOFTWARE_UPDATE_JSON_UPDATE_SIZE], 0);
                            const std::string hash = OSUtils::jsonBinFromHex(req[ZT_SOFTWARE_UPDATE_JSON_UPDATE_HASH]);
                            if ((len <= ZT_SOFTWARE_UPDATE_MAX_SIZE) && (hash.length() >= 16)) {
                                if (_latestMeta != req) {
                                    _latestMeta = req;
                                    _latestValid = false;
                                    OSUtils::rm((_homePath + ZT_PATH_SEPARATOR_S ZT_SOFTWARE_UPDATE_BIN_FILENAME).c_str());
                                    _download = std::string();
                                    memcpy(_downloadHashPrefix.data(), hash.data(), 16);
                                    _downloadLength = len;
                                }

                                if ((_downloadLength > 0) && (_download.length() < _downloadLength)) {
                                    Buffer<128> gd;
                                    gd.append((uint8_t)VERB_GET_DATA);
                                    gd.append(_downloadHashPrefix.data(), 16);
                                    gd.append((uint32_t)_download.length());
                                    _node.sendUserMessage((void*)0, ZT_SOFTWARE_UPDATE_SERVICE, ZT_SOFTWARE_UPDATE_USER_MESSAGE_TYPE, gd.data(), gd.size());
                                }
                            }
                        }
                    }
                }
            } break;

            case VERB_GET_DATA:
                if ((len >= 21) && (! _dist.empty())) {
                    unsigned long idx = (unsigned long)*(reinterpret_cast<const uint8_t*>(data) + 17) << 24;
                    idx |= (unsigned long)*(reinterpret_cast<const uint8_t*>(data) + 18) << 16;
                    idx |= (unsigned long)*(reinterpret_cast<const uint8_t*>(data) + 19) << 8;
                    idx |= (unsigned long)*(reinterpret_cast<const uint8_t*>(data) + 20);
                    std::array<uint8_t, 16> shakey;
                    memcpy(shakey.data(), reinterpret_cast<const uint8_t*>(data) + 1, 16);
                    std::map<std::array<uint8_t, 16>, _D>::iterator d(_dist.find(shakey));
                    if ((d != _dist.end()) && (idx < (unsigned long)d->second.bin.length())) {
                        Buffer<ZT_SOFTWARE_UPDATE_CHUNK_SIZE + 128> buf;
                        buf.append((uint8_t)VERB_DATA);
                        buf.append(reinterpret_cast<const uint8_t*>(data) + 1, 16);
                        buf.append((uint32_t)idx);
                        buf.append(d->second.bin.data() + idx, std::min((unsigned long)ZT_SOFTWARE_UPDATE_CHUNK_SIZE, (unsigned long)(d->second.bin.length() - idx)));
                        _node.sendUserMessage((void*)0, origin, ZT_SOFTWARE_UPDATE_USER_MESSAGE_TYPE, buf.data(), buf.size());
                    }
                }
                break;

            case VERB_DATA:
                if ((len >= 21) && (_downloadLength > 0) && (! memcmp(_downloadHashPrefix.data(), reinterpret_cast<const uint8_t*>(data) + 1, 16))) {
                    unsigned long idx = (unsigned long)*(reinterpret_cast<const uint8_t*>(data) + 17) << 24;
                    idx |= (unsigned long)*(reinterpret_cast<const uint8_t*>(data) + 18) << 16;
                    idx |= (unsigned long)*(reinterpret_cast<const uint8_t*>(data) + 19) << 8;
                    idx |= (unsigned long)*(reinterpret_cast<const uint8_t*>(data) + 20);
                    if (idx == (unsigned long)_download.length()) {
                        _download.append(reinterpret_cast<const char*>(data) + 21, len - 21);
                        if (_download.length() < _downloadLength) {
                            Buffer<128> gd;
                            gd.append((uint8_t)VERB_GET_DATA);
                            gd.append(_downloadHashPrefix.data(), 16);
                            gd.append((uint32_t)_download.length());
                            _node.sendUserMessage((void*)0, ZT_SOFTWARE_UPDATE_SERVICE, ZT_SOFTWARE_UPDATE_USER_MESSAGE_TYPE, gd.data(), gd.size());
                        }
                    }
                }
                break;

            default:
                if (_distLog) {
                    fprintf(_distLog, "%.10llx WARNING: bad update message verb==%u length==%u (unrecognized verb)" ZT_EOL_S, (unsigned long long)origin, (unsigned int)v, len);
                    fflush(_distLog);
                }
                break;
        }
    }
    catch (...) {
        if (_distLog) {
            fprintf(_distLog, "%.10llx WARNING: bad update message verb==%u length==%u (unexpected exception, likely invalid JSON)" ZT_EOL_S, (unsigned long long)origin, (unsigned int)v, len);
            fflush(_distLog);
        }
    }
}

bool SoftwareUpdater::check(const int64_t now)
{
    if ((now - _lastCheckTime) >= ZT_SOFTWARE_UPDATE_CHECK_PERIOD) {
        _lastCheckTime = now;
        char tmp[512];
        const unsigned int len = OSUtils::ztsnprintf(
            tmp,
            sizeof(tmp),
            "%c{\"" ZT_SOFTWARE_UPDATE_JSON_VERSION_MAJOR "\":%d,"
            "\"" ZT_SOFTWARE_UPDATE_JSON_VERSION_MINOR "\":%d,"
            "\"" ZT_SOFTWARE_UPDATE_JSON_VERSION_REVISION "\":%d,"
            "\"" ZT_SOFTWARE_UPDATE_JSON_VERSION_BUILD "\":%d,"
            "\"" ZT_SOFTWARE_UPDATE_JSON_EXPECT_SIGNED_BY "\":\"%s\","
            "\"" ZT_SOFTWARE_UPDATE_JSON_PLATFORM "\":%d,"
            "\"" ZT_SOFTWARE_UPDATE_JSON_ARCHITECTURE "\":%d,"
            "\"" ZT_SOFTWARE_UPDATE_JSON_VENDOR "\":%d,"
            "\"" ZT_SOFTWARE_UPDATE_JSON_CHANNEL "\":\"%s\"}",
            (char)VERB_GET_LATEST,
            ZEROTIER_ONE_VERSION_MAJOR,
            ZEROTIER_ONE_VERSION_MINOR,
            ZEROTIER_ONE_VERSION_REVISION,
            ZEROTIER_ONE_VERSION_BUILD,
            ZT_SOFTWARE_UPDATE_SIGNING_AUTHORITY,
            ZT_BUILD_PLATFORM,
            ZT_BUILD_ARCHITECTURE,
            (int)ZT_VENDOR_ZEROTIER,
            _channel.c_str());
        _node.sendUserMessage((void*)0, ZT_SOFTWARE_UPDATE_SERVICE, ZT_SOFTWARE_UPDATE_USER_MESSAGE_TYPE, tmp, len);
    }

    if (_latestValid)
        return true;

    if (_downloadLength > 0) {
        if (_download.length() >= _downloadLength) {
            // This is the very important security validation part that makes sure
            // this software update doesn't have cooties.

            const std::string binPath(_homePath + ZT_PATH_SEPARATOR_S ZT_SOFTWARE_UPDATE_BIN_FILENAME);
            try {
                // (1) Check the hash itself to make sure the image is basically okay
                uint8_t sha512[64];
                SHA512(sha512, _download.data(), (unsigned int)_download.length());
                char hexbuf[(64 * 2) + 2];
                if (OSUtils::jsonString(_latestMeta[ZT_SOFTWARE_UPDATE_JSON_UPDATE_HASH], "") == Utils::hex(sha512, 64, hexbuf)) {
                    // (2) Check signature by signing authority
                    const std::string sig(OSUtils::jsonBinFromHex(_latestMeta[ZT_SOFTWARE_UPDATE_JSON_UPDATE_SIGNATURE]));
                    if (Identity(ZT_SOFTWARE_UPDATE_SIGNING_AUTHORITY).verify(_download.data(), (unsigned int)_download.length(), sig.data(), (unsigned int)sig.length())) {
                        // (3) Try to save file, and if so we are good.
                        OSUtils::rm(binPath.c_str());
                        if (OSUtils::writeFile(binPath.c_str(), _download)) {
                            OSUtils::lockDownFile(binPath.c_str(), false);
                            _latestValid = true;
                            _download = std::string();
                            _downloadLength = 0;
                            return true;
                        }
                    }
                }
            }
            catch (...) {
            }   // any exception equals verification failure

            // If we get here, checks failed.
            OSUtils::rm(binPath.c_str());
            _latestMeta = nlohmann::json();
            _latestValid = false;
            _download = std::string();
            _downloadLength = 0;
        }
        else {
            Buffer<128> gd;
            gd.append((uint8_t)VERB_GET_DATA);
            gd.append(_downloadHashPrefix.data(), 16);
            gd.append((uint32_t)_download.length());
            _node.sendUserMessage((void*)0, ZT_SOFTWARE_UPDATE_SERVICE, ZT_SOFTWARE_UPDATE_USER_MESSAGE_TYPE, gd.data(), gd.size());
        }
    }

    return false;
}

void SoftwareUpdater::apply()
{
    std::string updatePath(_homePath + ZT_PATH_SEPARATOR_S ZT_SOFTWARE_UPDATE_BIN_FILENAME);
    if ((_latestMeta.is_object()) && (_latestValid) && (OSUtils::fileExists(updatePath.c_str(), false))) {
#ifdef __WINDOWS__
        std::string cmdArgs(OSUtils::jsonString(_latestMeta[ZT_SOFTWARE_UPDATE_JSON_UPDATE_EXEC_ARGS], ""));
        if (cmdArgs.length() > 0) {
            updatePath.push_back(' ');
            updatePath.append(cmdArgs);
        }
        STARTUPINFOA si;
        PROCESS_INFORMATION pi;
        memset(&si, 0, sizeof(si));
        memset(&pi, 0, sizeof(pi));
        CreateProcessA(NULL, const_cast<LPSTR>(updatePath.c_str()), NULL, NULL, FALSE, CREATE_NO_WINDOW | CREATE_NEW_PROCESS_GROUP, NULL, NULL, &si, &pi);
        // Windows doesn't exit here -- updater will stop the service during update, etc. -- but we do want to stop multiple runs from happening
        _latestMeta = nlohmann::json();
        _latestValid = false;
#else
        char* argv[256];
        unsigned long ac = 0;
        argv[ac++] = const_cast<char*>(updatePath.c_str());
        const std::vector<std::string> argsSplit(OSUtils::split(OSUtils::jsonString(_latestMeta[ZT_SOFTWARE_UPDATE_JSON_UPDATE_EXEC_ARGS], "").c_str(), " ", "\\", "\""));
        for (std::vector<std::string>::const_iterator a(argsSplit.begin()); a != argsSplit.end(); ++a) {
            argv[ac] = const_cast<char*>(a->c_str());
            if (++ac == 255)
                break;
        }
        argv[ac] = (char*)0;
        chmod(updatePath.c_str(), 0700);

        // Close all open file descriptors except stdout/stderr/etc.
        int minMyFd = STDIN_FILENO;
        if (STDOUT_FILENO > minMyFd)
            minMyFd = STDOUT_FILENO;
        if (STDERR_FILENO > minMyFd)
            minMyFd = STDERR_FILENO;
        ++minMyFd;
#ifdef _SC_OPEN_MAX
        int maxMyFd = (int)sysconf(_SC_OPEN_MAX);
        if (maxMyFd <= minMyFd)
            maxMyFd = 65536;
#else
        int maxMyFd = 65536;
#endif
        while (minMyFd < maxMyFd)
            close(minMyFd++);

        execv(updatePath.c_str(), argv);
        fprintf(stderr, "FATAL: unable to execute software update binary at %s\n", updatePath.c_str());
        exit(1);
#endif
    }
}

}   // namespace ZeroTier