<?php
/**
* Statify Filter: StatifyBlacklist class
*
* This file contains the plugin's base class.
*
* @package Statify_Blacklist
* @since 1.0.0
*/
// Quit if accessed directly.
if ( ! defined( 'ABSPATH' ) ) {
exit;
}
/**
* Statify Filter.
*/
class StatifyBlacklist {
/**
* Plugin major version.
*
* @since 1.4.0
* @var int VERSION_MAIN
*/
const VERSION_MAIN = 1.4;
/**
* Operation mode "normal".
*
* @var integer MODE_NORMAL
*/
const MODE_NORMAL = 0;
/**
* Operation mode "regular expression".
*
* @var integer MODE_REGEX
*/
const MODE_REGEX = 1;
/**
* Operation mode "regular expression case insensitive".
*
* @var integer MODE_REGEX_CI
*/
const MODE_REGEX_CI = 2;
/**
* Operation mode "keyword".
*
* @since 1.5.0
* @var integer MODE_KEYWORD
*/
const MODE_KEYWORD = 3;
/**
* Plugin options.
*
* @since 1.0.0
* @var array $options
*/
public static $options;
/**
* Multisite Status.
*
* @since 1.0.0
* @var bool $multisite
*/
public static $multisite;
/**
* Plugin initialization.
*
* @since 1.4.2
*
* @return void
*/
public static function init() {
// Skip on autosave.
if ( ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) ) {
return;
}
// Get multisite status.
self::$multisite = ( is_multisite() && array_key_exists( STATIFYBLACKLIST_BASE, (array) get_site_option( 'active_sitewide_plugins' ) ) );
// Plugin options.
self::update_options();
// Add Filter to statify hook if enabled.
if ( 0 !== self::$options['referer']['active'] ||
0 !== self::$options['target']['active'] ||
0 !== self::$options['ip']['active'] ||
0 !== self::$options['ua']['active'] ) {
add_filter( 'statify__skip_tracking', array( 'StatifyBlacklist', 'apply_blacklist_filter' ) );
}
// Statify uses WP AJAX as of 1.7, so we need to reach this point. But there are no further admin/cron actions.
if ( defined( 'DOING_AJAX' ) && DOING_AJAX ) {
return;
}
// Admin only filters.
if ( is_admin() ) {
StatifyBlacklist_Admin::init();
}
// CronJob to clean up database.
if ( defined( 'DOING_CRON' ) && DOING_CRON &&
( 1 === self::$options['referer']['cron'] || 1 === self::$options['target']['cron'] ) ) {
add_action( 'statify_cleanup', array( 'StatifyBlacklist_Admin', 'cleanup_database' ) );
}
}
/**
* Update options.
*
* @since 1.0.0
* @since 1.2.1 update_options($options = null) Parameter with default value introduced.
*
* @param array $options Optional. New options to save.
*
* @return void
*/
public static function update_options( $options = null ) {
if ( self::$multisite ) {
$o = get_site_option( 'statify-blacklist' );
} else {
$o = get_option( 'statify-blacklist' );
}
self::$options = wp_parse_args( $o, self::default_options() );
}
/**
* Create default plugin configuration.
*
* @since 1.4.0
*
* @return array The options array.
*/
protected static function default_options() {
return array(
'referer' => array(
'active' => 0,
'cron' => 0,
'regexp' => 0,
'blacklist' => array(),
),
'target' => array(
'active' => 0,
'cron' => 0,
'regexp' => 0,
'blacklist' => array(),
),
'ip' => array(
'active' => 0,
'blacklist' => array(),
),
'ua' => array(
'active' => 0,
'regexp' => 0,
'blacklist' => array(),
),
'version' => self::VERSION_MAIN,
);
}
/**
* Apply the filter if active
*
* @since 1.0.0
*
* @return bool TRUE if referer matches filter.
*/
public static function apply_blacklist_filter() {
// Referer filter.
if (
self::apply_single_filter(
self::$options['referer'],
array(
__CLASS__,
( ! isset( self::$options['referer']['regexp'] ) || self::MODE_NORMAL === self::$options['referer']['regexp'] ) ? 'get_referer_domain' : 'get_referer',
)
)
) {
return true;
}
// Target filter (since 1.4.0).
if ( self::apply_single_filter( self::$options['target'], array( __CLASS__, 'get_target' ) ) ) {
return true;
}
// IP filter (since 1.4.0).
if ( isset( self::$options['ip']['active'] ) && 0 !== self::$options['ip']['active'] ) {
$ip = self::get_ip();
if ( false !== ( $ip ) ) {
foreach ( self::$options['ip']['blacklist'] as $net ) {
if ( self::cidr_match( $ip, $net ) ) {
return true;
}
}
}
}
// User agent filter (since 1.6).
if ( self::apply_single_filter( self::$options['ua'], array( __CLASS__, 'get_user_agent' ) ) ) {
return true;
}
// Skip and continue (return NULL), if all filters are inactive.
return null;
}
/**
* Apply a single filter, if active.
*
* @param array $config Configuration array from plugin options.
* @param callable $value_fn Extractor function for filterable value.
*
* @return bool TRUE if referer matches filter.
*
* @since 1.6 Extracted from "apply_blacklist_filter" to reduce redundancies.
*/
private static function apply_single_filter( $config, $value_fn ) {
// Is the filter active?
if ( ! isset( $config['active'] ) || 0 === $config['active'] ) {
return false;
}
// Extract the filterable value.
$value = call_user_func( $value_fn );
$mode = isset( $config['regexp'] ) ? intval( $config['regexp'] ) : self::MODE_NORMAL;
switch ( $mode ) {
case self::MODE_REGEX:
case self::MODE_REGEX_CI:
// Regular Expression filtering since 1.3.0.
// Merge given regular expressions into one.
$regexp = self::regex(
array_keys( $config['blacklist'] ),
self::MODE_REGEX_CI === $config['regexp']
);
// Check filter (no return to continue filtering #12).
if ( 1 === preg_match( $regexp, $value ) ) {
return true;
}
break;
case self::MODE_KEYWORD:
// Keyword filter since 1.5.0 (#15).
foreach ( array_keys( $config['blacklist'] ) as $keyword ) {
if ( false !== strpos( strtolower( $value ), strtolower( $keyword ) ) ) {
return true;
}
}
break;
default:
// Standard exact filter.
if ( isset( $config['blacklist'][ $value ] ) ) {
return true;
}
}
return false;
}
/**
* Preprocess regular expression provided by the user, i.e. add delimiters and optional ci flag.
*
* @param string|array $expression Original expression string or array of expressions.
* @param string|array $case_insensitive Make expression match case-insensitive.
*
* @return string Preprocessed expression ready for preg_match().
*/
protected static function regex( $expression, $case_insensitive ) {
$res = '/';
if ( is_string( $expression ) ) {
$res .= str_replace( '/', '\/', $expression );
} elseif ( is_array( $expression ) ) {
$res .= implode(
'|',
array_map(
function ( $e ) {
return str_replace( '/', '\/', $e );
},
$expression
)
);
}
$res .= '/';
if ( $case_insensitive ) {
$res .= 'i';
}
return $res;
}
/**
* Helper method to determine the client's referer.
*
* @return string The referer.
*/
private static function get_referer() {
$referer = wp_get_raw_referer();
if ( ! $referer ) {
$referer = '';
}
return $referer;
}
/**
* Helper method to determine the host part of the client's referer.
*
* @return string Referer domain.
*/
private static function get_referer_domain() {
$referer = wp_parse_url( self::get_referer() );
return strtolower( ( isset( $referer['host'] ) ? $referer['host'] : '' ) );
}
/**
* Helper method to determine the client's referer.
*
* @return string The referer.
*/
private static function get_target() {
if ( isset( $_SERVER['REQUEST_URI'] ) ) {
$target = filter_var( wp_unslash( $_SERVER['REQUEST_URI'] ), FILTER_SANITIZE_URL );
if ( $target ) {
return $target;
}
}
return '';
}
/**
* Helper method to determine the client's IP address.
*
* If a proxy is used, the X-Real-IP or X-Forwarded-For header is checked, otherwise the default remote address.
* For performance reasons only the most common flags are checked. This might be even reduce by user configuration.
* Maybe some community feedback will ease the decision on that.
*
* @return string|bool the client's IP address or FALSE, if none could be determined.
*/
private static function get_ip() {
foreach (
/*
* There are more fields, that could possibly be checked, but we only consider the most common for now:
* HTTP_CLIENT_IP, HTTP_X_REAL_IP, HTTP_X_FORWARDED_FOR, HTTP_X_FORWARDED,
* HTTP_X_CLUSTER_CLIENT_IP, HTTP_FORWARDED_FOR, HTTP_FORWARDED, REMOTE_ADDR
*/
array(
'HTTP_X_REAL_IP',
'HTTP_X_FORWARDED_FOR',
'REMOTE_ADDR',
) as $k
) {
if ( isset( $_SERVER[ $k ] ) ) {
// phpcs:ignore
foreach ( explode( ',', $_SERVER[ $k ] ) as $ip ) {
if ( false !== filter_var( $ip, FILTER_VALIDATE_IP ) ) {
return $ip;
}
}
}
}
return false;
}
/**
* Helper method to determine the user agent.
*
* @return string The user agent string.
*/
private static function get_user_agent() {
if ( ! empty( $_SERVER['HTTP_USER_AGENT'] ) ) {
$user_agent = filter_var( wp_unslash( $_SERVER['HTTP_USER_AGENT'] ), FILTER_SANITIZE_STRING );
if ( $user_agent ) {
return $user_agent;
}
}
return '';
}
/**
* Helper function to check if an IP address matches a given subnet.
*
* @param string $ip IP address to check.
* @param string $net IP address or subnet in CIDR notation.
*
* @return bool TRUE, if the given IP addresses matches the given subnet.
*/
private static function cidr_match( $ip, $net ) {
if ( substr_count( $net, ':' ) > 1 ) { // Check for IPv6.
if ( ! ( ( extension_loaded( 'sockets' ) && defined( 'AF_INET6' ) ) || inet_pton( '::1' ) ) ) {
return false;
}
if ( false !== strpos( $net, '/' ) ) { // Parse CIDR subnet.
list( $base, $mask ) = explode( '/', trim( $net ), 2 );
if ( ! is_numeric( $mask ) ) {
return false;
} else {
$mask = (int) $mask;
}
if ( $mask < 1 || $mask > 128 ) {
return false;
}
} else {
$base = $net;
$mask = 128;
}
$bytes_addr = unpack( 'n*', inet_pton( $base ) );
$bytes_est = unpack( 'n*', inet_pton( $ip ) );
if ( ! $bytes_addr || ! $bytes_est ) {
return false;
}
$ceil = ceil( $mask / 16 );
for ( $i = 1; $i <= $ceil; ++ $i ) {
$left = $mask - 16 * ( $i - 1 );
$left = ( $left <= 16 ) ? $left : 16;
$mask_b = ~( 0xffff >> $left ) & 0xffff;
if ( ( $bytes_addr[ $i ] & $mask_b ) !== ( $bytes_est[ $i ] & $mask_b ) ) {
return false;
}
}
return true;
} else { // Check for IPv4.
if ( ! filter_var( $ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4 ) ) {
return false;
}
if ( false !== strpos( $net, '/' ) ) { // Parse CIDR subnet.
list( $base, $mask ) = explode( '/', $net, 2 );
if ( '0' === $mask ) {
return filter_var( $base, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4 );
}
if ( $mask < 0 || $mask > 32 ) {
return false;
}
} else { // Use single address.
$base = $net;
$mask = 32;
}
return ( 0 === substr_compare( sprintf( '%032b', ip2long( $ip ) ), sprintf( '%032b', ip2long( $base ) ), 0, $mask ) );
}
}
}