<?php
/**
 * @file security.php
 * @created_on 2018-05-27
 * @updated_on 2020-02-04
 * @author Go Namhyeon <gnh1201@gmail.com>
 * @brief Security module for ReasonableFramework
 * @sponsor https://patreon.com/catswords (with advanced security)
 */

if(!check_function_exists("check_token_abuse")) {
    function check_token_abuse($_p_token, $_n_token) {
        $abuse = false;

        $_c_token = $_p_token . $_n_token;
        if(empty($_c_token) || $_p_token != $_n_token || strlen($_c_token) != (strlen($_p_token) + strlen($_n_token)) || !ctype_alnum($_c_token)) {
            $abuse = true;
        }

        return $abuse;
    }
}

if(!check_function_exists("make_random_id")) {
    function make_random_id($length = 10) {
        $characters = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
        $charactersLength = strlen($characters);
        $randomString = '';
        for ($i = 0; $i < $length; $i++) {
            $randomString .= $characters[rand(0, $charactersLength - 1)];
        }
        return $randomString;
    }
}

if(!check_function_exists("set_session")) {
    function set_session($session_name, $value) {
        if(PHP_VERSION < '5.3.0') {
            session_register($session_name);
        }
        $$session_name = $_SESSION["$session_name"] = $value;
    }
}

if(!check_function_exists("get_session")) {
    function get_session($session_name) {
        $session_value = "";
        if(!array_key_empty($session_name, $_SESSION)) {
            $session_value = $_SESSION[$session_name];
        }
        return $session_value;
    }
}

if(!check_function_exists("set_session_token")) {
    function set_session_token() {
        $_token = make_random_id(10);
        set_session("_token", $_token);

        return $_token;
    }
}

if(!check_function_exists("get_session_token")) {
    function get_session_token() {
        return get_session("_token");
    }
}

if(!check_function_exists("check_token_abuse_by_requests")) {
    function check_token_abuse_by_requests($name, $method="_POST") {
        $requests = get_requests();

        $flag = false;
        if(array_key_empty($name, $requests[$method])) {
            $flag = true;
        } else {
            $flag = check_token_abuse($requests[$method][$name], get_session($name));
        }

        return $flag;
    }
}

if(!check_function_exists("check_login_session")) {
    function check_login_session($ss_key, $config) {
        $flag = false;

        $session_name = get_password($ss_key);
        $session_stored_name = read_storage_file($session_name, array(
            "storage_type" => get_value_in_array("session_dir", $config, "session"),
        ));
        $flag = !check_token_abuse($session_stored_name, $session_name);

        return $flag;
    }
}

if(!check_function_exists("store_login_session")) {
    function store_login_session($ss_key, $config) {
        $flag = false;

        $session_name = get_password($ss_key);
        $fw = write_storage_file($session_name, array(
            "filename" => $session_name,
            "storage_type" => get_value_in_array("session_dir", $config, "session"),
            "chmod" => 0700, // only access by owner
        ));

        if($fw) {
            $flag = check_login_session($ss_key, $config);
        }

        return $flag;
    }
}

if(!check_function_exists("process_safe_login")) {
    function process_safe_login($user_name, $user_password, $user_profile=array(), $escape_safe=false) {
        $config = get_config();

        $flag = false;
        $ss_key = get_session("ss_key");

        $user_id = 0;
        $stored_password = "";
        if(!array_key_empty("user_id", $user_profile)) {
            $user_id = $user_profile['user_id'];
        }
        if(!array_key_empty("user_password", $user_profile)) {
            $stored_password = $user_profile['user_password'];
        }

        if(!empty($ss_key) && check_login_session($ss_key, $config)) {
            $flag = false; // if alreay login, return false
        } else {
            $ss_key = make_random_id(10);

            if(check_match_password($stored_password, $user_password) || $escape_safe == true) {
                set_session("ss_user_id", $user_id);
                set_session("ss_user_name", $user_name);
                set_session("ss_key", $ss_key);

                $flag = store_login_session($ss_key, $config);
            }
        }

        return $flag;
    }
}

if(!check_function_exists("check_empty_requests")) {
    function check_empty_requests($fieldnames, $method="get") {
        $requests = get_requests();
        $errors = array();

        if(is_bool($method)) {
            $method = $method ? "get" : "post";
        }

        if(array_key_exists($method, $requests)) {
            $data = $requests[$method];

            foreach($fieldnames as $fieldname) {
                if(array_key_empty($fieldname, $data)) {
                    $errors[] = array(
                        "fieldname" => $fieldname,
                        "message"   => "{$fieldname}: can not empty."
                    );
                }
            }
        }

        return $errors;
    }
}

if(!check_function_exists("get_hash_algos")) {
    function get_hash_algos() {
        $config = get_config();
        $algos = explode(",", get_value_in_array("hashalgos", $config, "md5,sha1,crypt,crc32,base64,sql_password"));
        return $algos;
    }
}

if(!check_function_exists("check_hash_algo")) {
    function check_hash_algo($algo) {
        $flag = in_array($algo, get_hash_algos());
    }
}

if(!check_function_exists("get_hashed_text")) {
    function get_hashed_text($text, $algo="sha1", $options=array()) {
        $_text = false;

        // with salt
        if(!array_key_empty("salt", $options)) {
            if(!array_key_equals("2p", $options, true)) {
                if($options['salt'] == true) {
                    $text .= get_salt();
                } elseif(strlen($options['salt']) > 0) {
                    $text .= $options['salt'];
                }
            }
        }

        // with 2-pass hashing
        if(array_key_equals("2p", $options, true)) {
            $options['2p'] = false;
            $text = get_hashed_text($text, $algo, $options);
        }

        // choose algorithm
        switch($algo) {
            case "sha1":
                $_text = sha1($text);
                break;
            case "md5":
                $_text = md5($text);
                break;
            case "crypt":
                $_text = crypt($text);
                break;
            case "crc32":
                if(!array_key_equals("decimal", $options, true)) {
                    $_text = str_pad(dechex(crc32($text)), 8, '0', STR_PAD_LEFT);
                } else {
                    $_text = crc32($text);
                }
                break;
            case "base64":
                if(!array_key_equals("decode", $options, true)) {
                    $_text = base64_encode($text);
                } else {
                    $_text = base64_decode($text);
                }
                break;
            case "sql_password":
                $row = exec_db_fetch("select password(:text) as pw", array(
                    "text" => $text,
                ));
                $_text = get_value_in_array("pw", $row, $_text);
                break;
            default:
                if(check_hash_algo($algo)) {
                    $_text = hash($algo, $text, false);
                }
                break;
        }

        return $_text;
    }
}

if(!check_function_exists("get_compressed_text")) {
    function get_compressed_text($text, $algo="deflate", $options=array()) {
        $_text = "";

        switch($algo) {
            case "deflate":
                $_text = get_hashed_text(gzdeflate($text), "base64");
                break;
            case "gzip":
                $_text = get_hashed_text(gzencode($text), "base64");
                break;
            case "zlib":
                $_text = get_hashed_text(gzcompress($text), "base64");
                break;
            case "bzip":
                $_text = get_hashed_text(bzcompress($text), "base64");
                break;
            case "lzf":
                $_text = get_hashed_text(lzf_compress($text), "base64");
                break;
            default:
                $_text = $text;
        }

        return $_text;
    }
}

if(!check_function_exists("get_uncompressed_text")) {
    function get_uncompressed_text($text, $algo="deflate", $options=array()) {
        $_text = "";

        switch($algo) {
            case "deflate":
                $_text = gzinflate(base64_decode($text));
                break;
            case "gzip":
                $_text = gzdecode(base64_decode($text));
                break;
            case "zlib":
                $_text = gzuncompress(base64_decode($text));
                break;
            case "bzip":
                $_text = bzuncompress(base64_decode($text));
                break;
            case "lzf":
                $_text = lzf_decompress(base64_decode($text));
                break;
            default:
                $_text = $text;
        }

        return $_text;
    }
}

if(!check_function_exists("get_salt")) {
    function get_salt() {
        $salt = "";

        $config = get_config();
        if(!array_key_equals("saltdisabled", $config, 1)) {
            $salt = get_value_in_array("salt", $config, make_random_id(16));
        }

        return $salt;
    }
}

if(!check_function_exists("get_password")) {
    function get_password($text, $algo="sha1") {
        return get_hashed_text($text, $algo, array(
            "salt" => true,
        ));
    }
}

if(!check_function_exists("check_match_password")) {
    function check_match_password($p, $n, $algo="sha1") {
        $flag = false;
        $salt = get_salt();

        $n_plain_text = $n . $salt;
        $n_hashed_text = "";

        switch($algo) {
            case "crypt":
                $flag = (crypt($n_plain_text, $p) == $p);
                break;
            default:
                $n_hashed_text = get_hashed_text($n_plain_text, $algo);
                $flag = ($n_hashed_text == $p);
                break;
        }

        return $flag;
    }
}

if(!check_function_exists("protect_dir_path")) {
    function protect_dir_path($path) {
        $path = str_replace('/', '_', $path);
        return $path;
    }
}

if(!check_function_exists("session_logout")) {
    function session_logout() {
        $config = get_config();

        $flag = false;

        $ss_user_name = get_session("ss_user_name");
        $ss_key = get_session("ss_key");

        // delete session file
        $session_name = get_password($ss_key);
        remove_storage_file($session_name, array(
            "storage_type" => get_value_in_array("session_dir", $config, "session"),
        ));

        // reset session
        if(!empty($ss_key)) {
            set_session("ss_user_name", "");
            set_session("ss_key", "");
        }

        // permanently destory
        session_unset();
        session_destroy();

        // check ereased token
        $abuse_ss_user_name = check_token_abuse($ss_user_name, get_session("ss_user_name"));
        $abuse_ss_key = check_token_abuse($ss_key, get_session("ss_key"));

        // return result
        $flag = ($abuse_ss_user_name && $abuse_ss_key);

        return $flag;
    }
}

if(!check_function_exists("get_current_user_id")) {
    function get_current_user_id() {
        return get_current_session_data("ss_user_id");
    }
}

if(!check_function_exists("get_current_user_name")) {
    function get_current_user_name() {
        return get_current_session_data("ss_user_name");
    }
}

if(!check_function_exists("get_current_session_data")) {
    function get_current_session_data($name) {
        $current_data = "";

        $ss_data = get_session($name);
        $ss_key = get_session("ss_key");

        $abuse = check_token_abuse($ss_data, $ss_data); // self check
        $abuse = ($abuse && check_token_abuse($ss_key, $ss_key)); // self check

        if(!$abuse) {
            $current_data = $ss_data;
        }

        return $current_data;
    }
}

if(!check_function_exists("get_user_profile")) {
    function get_user_profile() {
        $user_profile = array(
            "user_id"   => get_current_user_id(),
            "user_name" => get_current_user_name()
        );

        return $user_profile;
    }
}

if(!check_function_exists("get_fixed_id")) {
    function get_fixed_id($str, $len=0, $salt="") {
        $config = get_config();

        $init_salt = empty($salt) ? $config['salt'] : $salt;
        $init_len = ($len < 1) ? $config['autolen'] : $len;
        return substr(get_hashed_text(get_hashed_text($str, "sha1") . $init_salt, "sha1"), 0, $init_len);
    }
}

// https://stackoverflow.com/questions/1996122/how-to-prevent-xss-with-html-php
if(!check_function_exists("get_clean_xss")) {
    function get_clean_xss($data, $notags=0) {
        if(is_string($data)) {
            // if no tags (equals to strip_tags)
            if($notags > 0) {
                return strip_tags($data);
            }

            // Fix &entity\n;
            $data = str_replace(array('&amp;','&lt;','&gt;'), array('&amp;amp;','&amp;lt;','&amp;gt;'), $data);
            $data = preg_replace('/(&#*\w+)[\x00-\x20]+;/u', '$1;', $data);
            $data = preg_replace('/(&#x*[0-9A-F]+);*/iu', '$1;', $data);
            $data = html_entity_decode($data, ENT_COMPAT, 'UTF-8');

            // Remove any attribute starting with "on" or xmlns
            $data = preg_replace('#(<[^>]+?[\x00-\x20"\'])(?:on|xmlns)[^>]*+>#iu', '$1>', $data);

            // Remove javascript: and vbscript: protocols
            $data = preg_replace('#([a-z]*)[\x00-\x20]*=[\x00-\x20]*([`\'"]*)[\x00-\x20]*j[\x00-\x20]*a[\x00-\x20]*v[\x00-\x20]*a[\x00-\x20]*s[\x00-\x20]*c[\x00-\x20]*r[\x00-\x20]*i[\x00-\x20]*p[\x00-\x20]*t[\x00-\x20]*:#iu', '$1=$2nojavascript...', $data);
            $data = preg_replace('#([a-z]*)[\x00-\x20]*=([\'"]*)[\x00-\x20]*v[\x00-\x20]*b[\x00-\x20]*s[\x00-\x20]*c[\x00-\x20]*r[\x00-\x20]*i[\x00-\x20]*p[\x00-\x20]*t[\x00-\x20]*:#iu', '$1=$2novbscript...', $data);
            $data = preg_replace('#([a-z]*)[\x00-\x20]*=([\'"]*)[\x00-\x20]*-moz-binding[\x00-\x20]*:#u', '$1=$2nomozbinding...', $data);

            // Only works in IE: <span style="width: expression(alert('Ping!'));"></span>
            $data = preg_replace('#(<[^>]+?)style[\x00-\x20]*=[\x00-\x20]*[`\'"]*.*?expression[\x00-\x20]*\([^>]*+>#i', '$1>', $data);
            $data = preg_replace('#(<[^>]+?)style[\x00-\x20]*=[\x00-\x20]*[`\'"]*.*?behaviour[\x00-\x20]*\([^>]*+>#i', '$1>', $data);
            $data = preg_replace('#(<[^>]+?)style[\x00-\x20]*=[\x00-\x20]*[`\'"]*.*?s[\x00-\x20]*c[\x00-\x20]*r[\x00-\x20]*i[\x00-\x20]*p[\x00-\x20]*t[\x00-\x20]*:*[^>]*+>#iu', '$1>', $data);

            // Remove namespaced elements (we do not need them)
            $data = preg_replace('#</*\w+:\w[^>]*+>#i', '', $data);

            do
            {
                // Remove really unwanted tags
                $old_data = $data;
                $data = preg_replace('#</*(?:applet|b(?:ase|gsound|link)|embed|frame(?:set)?|i(?:frame|layer)|l(?:ayer|ink)|meta|object|s(?:cript|tyle)|title|xml)[^>]*+>#i', '', $data);
            }
            while ($old_data !== $data);
        }

        // we are done...
        return $data;
    }
}

if(!check_function_exists("get_clean_newlines")) {
    function get_clean_newlines($data) {
        return is_string($data) ? trim(preg_replace('~[\r\n]+~', ' ', $data)) : $data;
    }
}

if(!check_function_exists("get_clean_text")) {
    function get_clean_text($data) {
        return is_string($data) ? get_clean_newlines(get_clean_xss($data, 1)) : $data;
    }
}

// support curl or jsonp(callback)
if(!check_function_exists("get_callable_token")) {
    function get_callable_token($token, $callback="", $charset="utf-8") {
        $callback = get_clean_xss($callback);
        $retdata = "";

        if(empty($callback)) {
            $retdata = $token;
        } else {
            $retdata = "function $callback() { return '$token'; }";
        }

        return $retdata;
    }
}

if(!check_function_exists("encapsulate_text")) {
    function encapsulate_text($text, $algo="aes-128-cbc", $key="", $iv="", $hash="", $hash_algo="sha1") {
        $config = get_config();

        $encapsulated_text = "";
        $encrypted_text = "";

        // when fail hash test
        if(!empty($hash)) {
            if($hash != get_hashed_text($text, $hash_algo)) {
                return $encapsulated_text;
            }
        }

        // initialize text
        $init_text = get_hashed_text($text, "base64");

        if($algo == "base64") {
            $encapsulated_text = $init_text;
        } else {
            $init_key = empty($key) ? $config['masterkey'] : $key;
            $init_iv = empty($iv) ? $config['masteriv'] : $iv;

            if(check_function_exists("openssl_encrypt")) {
                $encrypted_text = @openssl_encrypt($init_text, $algo, $init_key, true, $init_iv);
            } else {
                $encrypted_text = get_hashed_text(get_xor_text($init_key, $init_text), "base64", array(
                    "decode" => true,
                ));
            }

            if(!empty($encrypted_text)) {
                $encapsulated_text = get_hashed_text($encrypted_text, "base64");
            }
        }
 
        return $encapsulated_text;
    }
}

if(!check_function_exists("decapsulate_text")) {
    function decapsulate_text($text, $algo="aes-128-cbc", $key="", $iv="", $hash="", $hash_algo="sha1") {
        $config = get_config();

        $decapsulate_text = "";
        $decrypted_text = "";

        // initialize text
        $init_text = get_hashed_text($text, "base64", array(
            "decode" => true,
        ));

        if($algo = "base64") {
            $decapsulate_text = $init_text;
        } else {
            $init_key = empty($key) ? $config['masterkey'] : $key;
            $init_iv = empty($iv) ? $config['masteriv'] : $iv;

            if(!check_function_exists("openssl_decrypt")) {
                $decrypted_text = @openssl_decrypt($init_text, $algo, $init_key, true, $init_iv);
            } else {
                $encrypted_text = get_hashed_text(get_xor_text($init_key, $init_text), "base64", array(
                    "decode" => true,
                ));
            }

            if(!empty($encrypted_text)) {
                $decapsulate_text = get_hashed_text($decrypted_text, "base64", array(
                    "decode" => true,
                ));
            }
        }

        // when fail hash test
        if(!empty($hash)) {
            if($hash != get_hashed_text($decapsulate_text, $hash_algo)) {
                $decapsulate_text = "";
            }
        }

        return $decapsulate_text;
    }
}

if(!check_function_exists("make_safe_argument")) {
    function make_safe_argument($str) {
        return is_string($str) ? addslashes($str) : $str;
    }
}

// https://stackoverflow.com/questions/14673551/encrypt-decrypt-with-xor-in-php
if(!check_function_exists("get_xor_text")) {
    function get_xor_text($key, $string, $debug=false) {
        $text = $string;
        $outText = "";

        for($i = 0; $i < strlen($text); ) {
            for($j = 0; ($j < strlen($key) && $i < strlen($text)); $j++, $i++) {
                $outText .= $text{$i} ^ $key{$j};

                if($debug) {
                    echo 'i=' . $i . ', ' . 'j=' . $j . ', ' . $outText{$i} . '<br />';
                }
            }
        }

        return get_hashed_text($outText, "base64");
    }
}

if(!check_function_exists("get_random_index")) {
    function get_random_index($data) {
        $index = 0;

        if(is_array($data)) {
            $d = array_keys($data);
            if(count($d) > 0) {
                shuffle($d);
                $index = $d[0];
            }
        }

        return $index;
    }
}

// https://wiki.ubuntu.com/DevelopmentCodeNames
if(!check_function_exists("get_generated_name")) {
    function get_generated_name() {
        $config = get_config();

        $generated_name = "";

        $adjectives = explode(',', $config['adjectives']);
        $animals = explode(',', $config['animals']);

        $c_adjective = ucfirst($adjectives[get_random_index($adjectives)]);
        $c_animal = ucfirst($animals[get_random_index($animals)]);

        $generated_name = $c_adjective . " " . $c_animal;

        return $generated_name;
    }
}

if(!check_function_exists("check_redirect_origin")) {
    function check_redirect_origin($url) {
        $flag = false;

        $to_resource = parse_url($url);
        $to_host = str_replace("www.", "", get_value_in_array("host", $to_resource, ""));

        $base_url = base_url();
        $base_resource = parse_url($base_url);
        $base_host = str_replace("www.", "", get_value_in_array("host", $base_resource, ""));

        $flag = !check_token_abuse($to_host, $base_host);

        return $flag;
    }
}

// since 1.6 or above
if(!check_function_exists("start_isolated_session")) {
    function start_isolated_session() {
        $config = get_config();
        if(!array_key_equals("sandboxdisabled", $config, 1)) {
            $cwd = get_current_working_dir();
            $session_dir = $cwd . "/storage/sandbox/sessions";
            session_save_path($session_dir);
            @ini_set("session.save_path", $session_dir);
            @ini_set("session.gc_probability", 1); // enable gc(gabage collection)
        }
        session_start(); // enable $_SESSION
    }
}

// since 1.6 or above
if(!check_function_exists("expire_isolated_session")) {
    function expire_isolated_session() {
        $_SESSION = array();
        session_destroy();
    }
}
