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<?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: Rock Lobster Inc. |
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* Author URI: https://github.com/rocklobster-in/ |
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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: 2.5 |
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* Requires at least: 7.1 |
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* Requires PHP: 8.3 |
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*/ |
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|
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if ( ! defined( 'ABSPATH' ) ) exit; // Exit if accessed directly |
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|
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define( 'REALLYSIMPLECAPTCHA_VERSION', '2.5' ); |
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|
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require_once __DIR__ . '/includes/filesystem.php'; |
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|
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class ReallySimpleCaptcha { |
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|
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use ReallySimpleCaptcha_Filesystem; |
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|
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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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/** |
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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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/** |
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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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/** |
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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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/** |
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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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/** |
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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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/** |
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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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/** |
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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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/** |
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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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/** |
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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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/** |
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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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/** |
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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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/** |
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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 $answer_file_mode = 0640; |
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|
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|
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/** |
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* Constructor. |
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*/ |
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public function __construct() { |
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$this->connect(); |
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} |
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|
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|
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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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|
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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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|
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return $word; |
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} |
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|
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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 ( ! $this->make_tmp_dir() ) { |
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return false; |
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} |
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|
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$this->cleanup(); |
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|
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$dir = trailingslashit( $this->tmp_dir ); |
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$filename = null; |
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|
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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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|
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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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|
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imagefill( $im, 0, 0, $bg ); |
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|
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$x = $this->base[0] + wp_rand( -2, 2 ); |
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|
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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( $font ); |
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|
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imagettftext( |
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$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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|
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$x += $this->font_char_width; |
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} |
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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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|
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imagedestroy( $im ); |
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|
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$this->chmod( $file, $this->file_mode ); |
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} |
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|
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$this->generate_answer_file( $prefix, $word ); |
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|
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return $filename; |
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} |
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|
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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( $answer_file ); |
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|
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$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 . '|' . $hash; |
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|
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$this->put_contents( $answer_file, $code, $this->answer_file_mode ); |
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} |
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|
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|
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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( $prefix ) ) { |
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return false; |
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} |
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|
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$response = str_replace( array( " ", "\t" ), '', $response ); |
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$response = strtoupper( $response ); |
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|
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$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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|
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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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|
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return hash_equals( $hash, hash_hmac( 'sha256', $response, $salt ) ); |
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} |
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|
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return false; |
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} |
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|
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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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|
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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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|
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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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|
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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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|
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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( $dir ) |
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) { |
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return false; |
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} |
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|
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$count = 0; |
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|
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if ( $handle = opendir( $dir ) ) { |
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while ( false !== ( $filename = readdir( $handle ) ) ) { |
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if ( ! preg_match( '/^[0-9]+\.(php|txt|png|gif|jpeg)$/', $filename ) ) { |
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continue; |
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} |
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|
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$file = wp_normalize_path( path_join( $dir, $filename ) ); |
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|
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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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|
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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( $file ); |
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} |
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|
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$count += 1; |
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} |
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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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|
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closedir( $handle ); |
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} |
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|
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return $count; |
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} |
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|
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|
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/** |
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* Make a temporary directory and generate .htaccess file in it. |
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* |
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* @return bool True on successful create, false on failure. |
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*/ |
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public function make_tmp_dir() { |
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$dir = trailingslashit( $this->tmp_dir ); |
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$dir = wp_normalize_path( $dir ); |
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|
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if ( ! wp_mkdir_p( $dir ) ) { |
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return false; |
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} |
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|
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$htaccess_file = wp_normalize_path( path_join( $dir, '.htaccess' ) ); |
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|
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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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|
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if ( '# Apache 2.4+' === $first_line_comment ) { |
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return true; |
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} |
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} |
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|
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$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)$"> |
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Require all granted |
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</FilesMatch> |
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</IfModule> |
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|
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# Apache 2.2 |
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<IfModule !authz_core_module> |
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Order deny,allow |
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Deny from all |
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<FilesMatch "^\w+\.(jpe?g|gif|png)$"> |
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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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|
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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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} |
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|
