<?php

/*
 * Copyright (C) 2018 Deciso B.V.
 * Copyright (C) 2018-2021 Franco Fichtner <franco@opnsense.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

namespace OPNsense\Backup;

use OPNsense\Core\AppConfig;
use OPNsense\Core\Shell;

/**
 * Backup stub file, contains shared logic for all backup strategies
 * @package OPNsense\Backup
 */
abstract class Base
{
    /**
     * get a temporary unique file on the disk
     * @return string file name
     */
    private function tempFile()
    {
        return tempnam((new AppConfig())->application->tempDir, 'php-encrypt-');
    }

    /**
     * encrypt+encode base64
     * @param string $data to encrypt
     * @param string $pass passphrase to use
     * @param string $tag
     * @return string base64 encoded crypted data
     */
    public function encrypt($data, $pass, $tag = 'config.xml')
    {
        $file = $this->tempFile();
        @unlink("{$file}.enc");

        /* current encryption defaults, change as needed */
        $cipher = 'aes-256-cbc';
        $hash = 'sha512';
        $pbkdf2 = '100000';

        file_put_contents($file, $pass);
        file_put_contents("{$file}.dec", $data);

        $retval = Shell::run_safe(
            '/usr/local/bin/openssl enc -e -%s -md %s -pbkdf2 -iter %s -in %s -out %s -pass file:%s 2> /dev/null',
            [$cipher, $hash, $pbkdf2, "{$file}.dec", "{$file}.enc", $file]
        );

        @unlink("{$file}.dec");
        @unlink($file);

        if (file_exists("{$file}.enc") && !$retval) {
            $version = Shell::shell_safe('opnsense-version -Nv');
            $result = "---- BEGIN {$tag} ----\n";
            $result .= "Version: {$version}\n";
            $result .= "Cipher: " . strtoupper($cipher) . "\n";
            $result .= "PBKDF2: " . $pbkdf2 . "\n";
            $result .= "Hash: " . strtoupper($hash) . "\n\n";
            $result .= chunk_split(base64_encode(file_get_contents("{$file}.enc")), 76, "\n");
            $result .= "---- END {$tag} ----\n";
            @unlink("{$file}.enc");
            return $result;
        } else {
            syslog(LOG_ERR, 'Failed to encrypt data!');
            @unlink("{$file}.enc");
            return null;
        }
    }

    /**
     * decrypt base64 encoded data
     * @param string $data to decrypt
     * @param string $pass passphrase to use
     * @param string $tag
     * @return string data
     */
    public function decrypt($data, $pass, $tag = 'config.xml')
    {
        $file = $this->tempFile();
        @unlink("{$file}.dec");

        $data = explode("\n", $data);

        /* pre-21.7 compat defaults, do not change */
        $cipher = 'aes-256-cbc';
        $hash = 'md5';
        $pbkdf2 = null;

        foreach ($data as $key => $val) {
            if (strpos($val, ':') !== false) {
                list ($header, $value) = explode(':', $val);
                $value = trim($value);
                switch (strtolower(trim($header))) {
                    case 'cipher':
                        $cipher = strtolower($value);
                        break;
                    case 'hash':
                        $hash = strtolower($value);
                        break;
                    case 'pbkdf2':
                        $pbkdf2 = $value;
                        break;
                    default:
                        /* skip unknown */
                        break;
                }
                unset($data[$key]);
            } elseif (strpos($val, "---- BEGIN {$tag} ----") !== false) {
                unset($data[$key]);
            } elseif (strpos($val, "---- END {$tag} ----") !== false) {
                unset($data[$key]);
            }
        }

        $data = implode("\n", $data);

        file_put_contents($file, $pass);
        file_put_contents("{$file}.enc", base64_decode($data));

        $frmt = ['/usr/local/bin/openssl enc -d -%s -md %s'];
        $args = [$cipher, $hash];

        if ($pbkdf2 !== null) {
            $frmt[] = '-pbkdf2 -iter=%s';
            $args[] = $pbkdf2;
        }

        $frmt[] = '-in %s -out %s -pass file:%s 2> /dev/null';
        $args[] = "{$file}.enc";
        $args[] = "{$file}.dec";
        $args[] = $file;

        $retval = Shell::run_safe($frmt, $args);

        @unlink("{$file}.enc");
        @unlink($file);

        if (file_exists("{$file}.dec") && !$retval) {
            $result = file_get_contents("{$file}.dec");
            @unlink("{$file}.dec");
            return $result;
        } else {
            syslog(LOG_ERR, 'Failed to decrypt data!');
            @unlink("{$file}.dec");
            return null;
        }
    }

    /**
     * set model properties
     * @param OPNsense\Base\BaseModel $mdl model to set properties to
     * @param array $properties named
     */
    protected function setModelProperties($mdl, $properties)
    {
        foreach ($properties as $key => $value) {
            $node = $mdl->getNodeByReference($key);
            $node_class = get_class($node);
            if ($node_class == "OPNsense\Base\FieldTypes\BooleanField") {
                $node->setValue(empty($value) ? "0" : "1");
            } else {
                $node->setValue($value);
            }
        }
    }

    /**
     * validate model and return simple array with validation messages
     * @param OPNsense\Base\BaseModel $mdl model to set properties to
     * @return array
     */
    protected function validateModel($mdl)
    {
        $result = array();
        foreach ($mdl->performValidation() as $validation_message) {
            $result[] = (string)$validation_message;
        }
        return $result;
    }
}
