forked from LiveCarta/LiveCartaWP
390 lines
8.8 KiB
PHP
390 lines
8.8 KiB
PHP
<?php
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/*
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* Plugin Name: Really Simple CAPTCHA
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* Plugin URI: https://contactform7.com/captcha/
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* Description: Really Simple CAPTCHA is a CAPTCHA module intended to be called from other plugins. It is originally created for my Contact Form 7 plugin.
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* Author: Takayuki Miyoshi
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* Author URI: https://ideasilo.wordpress.com/
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* License: GPL v2 or later
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* License URI: https://www.gnu.org/licenses/gpl-2.0.html
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* Version: 2.4
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* Requires at least: 6.6
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* Requires PHP: 7.4
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*/
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define( 'REALLYSIMPLECAPTCHA_VERSION', '2.4' );
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require_once __DIR__ . '/includes/filesystem.php';
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class ReallySimpleCaptcha {
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use ReallySimpleCaptcha_Filesystem;
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/**
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* Characters available in a CAPTCHA image.
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*
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* @var string All characters that can be used in a CAPTCHA image.
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*/
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public $chars = 'ABCDEFGHJKLMNPQRSTUVWXYZ23456789';
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/**
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* Number of characters that are displayed in a CAPTCHA image.
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*
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* @var int
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*/
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public $char_length = 4;
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/**
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* Font paths. Randomly picked up from the list per character.
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*
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* @var array
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*/
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public $fonts = array(
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__DIR__ . '/gentium/GenBkBasR.ttf',
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__DIR__ . '/gentium/GenBkBasI.ttf',
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__DIR__ . '/gentium/GenBkBasBI.ttf',
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__DIR__ . '/gentium/GenBkBasB.ttf',
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);
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/**
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* Temp directory for CAPTCHA images and text files.
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*
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* @var string
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*/
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public $tmp_dir = __DIR__ . '/tmp';
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/**
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* Array of CAPTCHA image size.
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*
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* @var array 0: Width, 1: Height (in pixels)
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*/
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public $img_size = array( 72, 24 );
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/**
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* Background color of a CAPTCHA image in RGB-notation.
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*
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* @var array 0: R, 1: G, 2: B (each within 0-255)
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*/
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public $bg = array( 255, 255, 255 );
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/**
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* Foreground (character) color of a CAPTCHA image in RGB-notation.
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*
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* @var array 0: R, 1: G, 2: B (each within 0-255)
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*/
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public $fg = array( 0, 0, 0 );
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/**
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* Coordinates for a text in an image. I don't know the meaning. Just adjust.
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*
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* @var array
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*/
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public $base = array( 6, 18 );
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/**
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* Font size.
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*
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* @var int
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*/
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public $font_size = 14;
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/**
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* Width of a character.
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*
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* @var int
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*/
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public $font_char_width = 15;
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/**
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* Image type.
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*
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* @var string png, gif, or jpeg.
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*/
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public $img_type = 'png';
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/**
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* File mode set for a CAPTCHA image.
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*
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* @var int
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*/
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public $file_mode = 0644;
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/**
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* File mode set for an answer text file.
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*
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* @var int
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*/
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public $answer_file_mode = 0640;
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/**
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* Constructor.
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*/
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public function __construct() {
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$this->connect();
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}
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/**
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* Generate and return a random word.
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*
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* @return string Random word with $chars characters x $char_length length
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*/
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public function generate_random_word() {
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$word = '';
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for ( $i = 0; $i < $this->char_length; $i++ ) {
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$pos = wp_rand( 0, strlen( $this->chars ) - 1 );
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$char = $this->chars[$pos];
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$word .= $char;
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}
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return $word;
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}
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/**
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* Generate CAPTCHA image and corresponding answer file.
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*
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* @param string $prefix File prefix used for both files
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* @param string $word Random word generated by generate_random_word()
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* @return string|bool The file name of the CAPTCHA image. Return false if temp directory is not available.
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*/
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public function generate_image( $prefix, $word ) {
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if ( ! $this->make_tmp_dir() ) {
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return false;
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}
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$this->cleanup();
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$dir = trailingslashit( $this->tmp_dir );
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$filename = null;
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$im = imagecreatetruecolor(
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$this->img_size[0],
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$this->img_size[1]
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);
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if ( $im ) {
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$bg = imagecolorallocate( $im, $this->bg[0], $this->bg[1], $this->bg[2] );
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$fg = imagecolorallocate( $im, $this->fg[0], $this->fg[1], $this->fg[2] );
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imagefill( $im, 0, 0, $bg );
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$x = $this->base[0] + wp_rand( -2, 2 );
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for ( $i = 0; $i < strlen( $word ); $i++ ) {
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$font = $this->fonts[array_rand( $this->fonts )];
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$font = wp_normalize_path( $font );
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imagettftext(
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$im, $this->font_size, wp_rand( -12, 12 ), $x,
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$this->base[1] + wp_rand( -2, 2 ), $fg, $font, $word[$i]
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);
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$x += $this->font_char_width;
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}
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switch ( $this->img_type ) {
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case 'jpeg':
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$filename = sanitize_file_name( $prefix . '.jpeg' );
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$file = wp_normalize_path( path_join( $dir, $filename ) );
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imagejpeg( $im, $file );
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break;
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case 'gif':
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$filename = sanitize_file_name( $prefix . '.gif' );
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$file = wp_normalize_path( path_join( $dir, $filename ) );
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imagegif( $im, $file );
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break;
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case 'png':
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default:
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$filename = sanitize_file_name( $prefix . '.png' );
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$file = wp_normalize_path( path_join( $dir, $filename ) );
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imagepng( $im, $file );
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}
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imagedestroy( $im );
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$this->chmod( $file, $this->file_mode );
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}
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$this->generate_answer_file( $prefix, $word );
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return $filename;
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}
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/**
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* Generate answer file corresponding to CAPTCHA image.
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*
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* @param string $prefix File prefix used for answer file
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* @param string $word Random word generated by generate_random_word()
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*/
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public function generate_answer_file( $prefix, $word ) {
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$dir = trailingslashit( $this->tmp_dir );
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$answer_file = path_join( $dir, sanitize_file_name( $prefix . '.txt' ) );
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$answer_file = wp_normalize_path( $answer_file );
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$word = strtoupper( $word );
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$salt = wp_generate_password( 64 );
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$hash = hash_hmac( 'sha256', $word, $salt );
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$code = $salt . '|' . $hash;
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$this->put_contents( $answer_file, $code, $this->answer_file_mode );
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}
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/**
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* Check a response against the code kept in the temporary file.
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*
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* @param string $prefix File prefix used for both files
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* @param string $response CAPTCHA response
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* @return bool Return true if the two match, otherwise return false.
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*/
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public function check( $prefix, $response ) {
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if ( 0 === strlen( $prefix ) ) {
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return false;
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}
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$response = str_replace( array( " ", "\t" ), '', $response );
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$response = strtoupper( $response );
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$dir = trailingslashit( $this->tmp_dir );
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$filename = sanitize_file_name( $prefix . '.txt' );
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$file = wp_normalize_path( path_join( $dir, $filename ) );
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if ( is_readable( $file ) and $code = $this->get_contents( $file ) ) {
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$code = explode( '|', $code, 2 );
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$salt = $code[0];
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$hash = $code[1];
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return hash_equals( $hash, hash_hmac( 'sha256', $response, $salt ) );
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}
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return false;
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}
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/**
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* Remove temporary files with given prefix.
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*
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* @param string $prefix File prefix
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*/
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public function remove( $prefix ) {
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$dir = trailingslashit( $this->tmp_dir );
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$suffixes = array( '.jpeg', '.gif', '.png', '.php', '.txt' );
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foreach ( $suffixes as $suffix ) {
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$filename = sanitize_file_name( $prefix . $suffix );
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$file = wp_normalize_path( path_join( $dir, $filename ) );
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if ( is_file( $file ) ) {
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$this->delete( $file );
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}
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}
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}
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/**
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* Clean up dead files older than given length of time.
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*
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* @param int $minutes Consider older files than this time as dead files
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* @return int|bool The number of removed files. Return false if error occurred.
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*/
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public function cleanup( $minutes = 60, $max = 100 ) {
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$dir = trailingslashit( $this->tmp_dir );
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$dir = wp_normalize_path( $dir );
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if (
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! is_dir( $dir ) or
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! is_readable( $dir ) or
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! wp_is_writable( $dir )
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) {
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return false;
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}
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$count = 0;
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if ( $handle = opendir( $dir ) ) {
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while ( false !== ( $filename = readdir( $handle ) ) ) {
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if ( ! preg_match( '/^[0-9]+\.(php|txt|png|gif|jpeg)$/', $filename ) ) {
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continue;
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}
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$file = wp_normalize_path( path_join( $dir, $filename ) );
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if ( ! file_exists( $file ) or ! $stat = stat( $file ) ) {
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continue;
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}
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if ( ( $stat['mtime'] + $minutes * MINUTE_IN_SECONDS ) < time() ) {
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if ( ! $this->delete( $file ) ) {
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$this->chmod( $file, 0644 );
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$this->delete( $file );
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}
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$count += 1;
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}
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if ( $max <= $count ) {
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break;
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}
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}
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closedir( $handle );
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}
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return $count;
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}
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/**
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* Make a temporary directory and generate .htaccess file in it.
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*
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* @return bool True on successful create, false on failure.
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*/
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public function make_tmp_dir() {
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$dir = trailingslashit( $this->tmp_dir );
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$dir = wp_normalize_path( $dir );
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if ( ! wp_mkdir_p( $dir ) ) {
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return false;
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}
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$htaccess_file = wp_normalize_path( path_join( $dir, '.htaccess' ) );
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if ( file_exists( $htaccess_file ) ) {
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list( $first_line_comment ) = (array) file(
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$htaccess_file,
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FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES
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);
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if ( '# Apache 2.4+' === $first_line_comment ) {
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return true;
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}
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}
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$htaccess_body = '
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# Apache 2.4+
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<IfModule authz_core_module>
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Require all denied
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<FilesMatch "^\w+\.(jpe?g|gif|png)$">
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Require all granted
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</FilesMatch>
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</IfModule>
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# Apache 2.2
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<IfModule !authz_core_module>
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Order deny,allow
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Deny from all
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<FilesMatch "^\w+\.(jpe?g|gif|png)$">
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Allow from all
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</FilesMatch>
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</IfModule>
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';
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return $this->put_contents( $htaccess_file, ltrim( $htaccess_body ), 0644 );
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}
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}
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