math-fallback.php
| 1 | <?php |
| 2 | |
| 3 | if ( ! class_exists( 'Jetpack_Protect_Math_Authenticate' ) ) { |
| 4 | /* |
| 5 | * The math captcha fallback if we can't talk to the Protect API |
| 6 | */ |
| 7 | class Jetpack_Protect_Math_Authenticate { |
| 8 | |
| 9 | static $loaded; |
| 10 | |
| 11 | function __construct() { |
| 12 | |
| 13 | if ( self::$loaded ) { |
| 14 | return; |
| 15 | } |
| 16 | |
| 17 | self::$loaded = 1; |
| 18 | |
| 19 | add_action( 'login_form', array( $this, 'math_form' ) ); |
| 20 | |
| 21 | if( isset( $_POST[ 'jetpack_protect_process_math_form' ] ) ) { |
| 22 | add_action( 'init', array( $this, 'process_generate_math_page' ) ); |
| 23 | } |
| 24 | } |
| 25 | |
| 26 | private static function time_window() { |
| 27 | return ceil( time() / ( MINUTE_IN_SECONDS * 2 ) ); |
| 28 | } |
| 29 | |
| 30 | /** |
| 31 | * Verifies that a user answered the math problem correctly while logging in. |
| 32 | * |
| 33 | * @return bool Returns true if the math is correct |
| 34 | * @throws Error if insuffient $_POST variables are present. |
| 35 | * @throws Error message if the math is wrong |
| 36 | */ |
| 37 | static function math_authenticate() { |
| 38 | if( isset( $_COOKIE[ 'jpp_math_pass' ] ) ) { |
| 39 | $jetpack_protect = Jetpack_Protect_Module::instance(); |
| 40 | $transient = $jetpack_protect->get_transient( 'jpp_math_pass_' . $_COOKIE[ 'jpp_math_pass' ] ); |
| 41 | |
| 42 | if( !$transient || $transient < 1 ) { |
| 43 | Jetpack_Protect_Math_Authenticate::generate_math_page(); |
| 44 | } |
| 45 | return true; |
| 46 | } |
| 47 | |
| 48 | $ans = isset( $_POST['jetpack_protect_num'] ) ? (int) $_POST['jetpack_protect_num'] : '' ; |
| 49 | $correct_ans = isset( $_POST[ 'jetpack_protect_answer' ] ) ? $_POST[ 'jetpack_protect_answer' ] : '' ; |
| 50 | |
| 51 | $time_window = Jetpack_Protect_Math_Authenticate::time_window(); |
| 52 | $salt = get_site_option( 'jetpack_protect_key' ) . '|' . get_site_option( 'admin_email' ) . '|'; |
| 53 | $salted_ans_1 = hash_hmac( 'sha1', $ans, $salt . $time_window ); |
| 54 | $salted_ans_2 = hash_hmac( 'sha1', $ans, $salt . ( $time_window - 1 ) ); |
| 55 | |
| 56 | if ( ! $correct_ans || ! $ans ) { |
| 57 | Jetpack_Protect_Math_Authenticate::generate_math_page(); |
| 58 | } elseif ( ! hash_equals( $salted_ans_1, $correct_ans ) && ! hash_equals( $salted_ans_2, $correct_ans ) ) { |
| 59 | wp_die( |
| 60 | __( '<strong>You failed to correctly answer the math problem.</strong> This is used to combat spam when the Protect API is unavailable. Please use your browser\'s back button to return to the login form, press the "refresh" button to generate a new math problem, and try to log in again.', 'jetpack' ), |
| 61 | '', |
| 62 | array ( 'response' => 401 ) |
| 63 | ); |
| 64 | } else { |
| 65 | return true; |
| 66 | } |
| 67 | } |
| 68 | |
| 69 | /** |
| 70 | * Creates an interim page to collect answers to a math captcha |
| 71 | * |
| 72 | * @return none, execution stopped |
| 73 | */ |
| 74 | static function generate_math_page( $error = false ) { |
| 75 | ob_start(); |
| 76 | ?> |
| 77 | <h2><?php esc_html_e( 'Please solve this math problem to prove that you are not a bot. Once you solve it, you will need to log in again.', 'jetpack' ); ?></h2> |
| 78 | <?php if ($error): ?> |
| 79 | <h3><?php esc_html_e( 'Your answer was incorrect, please try again.', 'jetpack' ); ?></h3> |
| 80 | <?php endif ?> |
| 81 | |
| 82 | <form action="<?php echo wp_login_url(); ?>" method="post" accept-charset="utf-8"> |
| 83 | <?php Jetpack_Protect_Math_Authenticate::math_form(); ?> |
| 84 | <input type="hidden" name="jetpack_protect_process_math_form" value="1" id="jetpack_protect_process_math_form" /> |
| 85 | <p><input type="submit" value="<?php esc_attr_e( 'Continue →', 'jetpack' ); ?>"></p> |
| 86 | </form> |
| 87 | <?php |
| 88 | $mathpage = ob_get_contents(); |
| 89 | ob_end_clean(); |
| 90 | wp_die( |
| 91 | $mathpage, |
| 92 | '', |
| 93 | array ( 'response' => 401 ) |
| 94 | ); |
| 95 | } |
| 96 | |
| 97 | public function process_generate_math_page() { |
| 98 | $ans = isset( $_POST['jetpack_protect_num'] ) ? (int)$_POST['jetpack_protect_num'] : ''; |
| 99 | $correct_ans = isset( $_POST[ 'jetpack_protect_answer' ] ) ? $_POST[ 'jetpack_protect_answer' ] : '' ; |
| 100 | |
| 101 | $time_window = Jetpack_Protect_Math_Authenticate::time_window(); |
| 102 | $salt = get_site_option( 'jetpack_protect_key' ) . '|' . get_site_option( 'admin_email' ) . '|'; |
| 103 | $salted_ans_1 = hash_hmac( 'sha1', $ans, $salt . $time_window ); |
| 104 | $salted_ans_2 = hash_hmac( 'sha1', $ans, $salt . ( $time_window - 1 ) ); |
| 105 | |
| 106 | if ( ! hash_equals( $salted_ans_1, $correct_ans ) && ! hash_equals( $salted_ans_2, $correct_ans ) ) { |
| 107 | Jetpack_Protect_Math_Authenticate::generate_math_page(true); |
| 108 | } else { |
| 109 | $temp_pass = substr( hash_hmac( 'sha1', rand( 1, 100000000 ), get_site_option( 'jetpack_protect_key' ) ), 5, 25 ); |
| 110 | |
| 111 | $jetpack_protect = Jetpack_Protect_Module::instance(); |
| 112 | $jetpack_protect->set_transient( 'jpp_math_pass_' . $temp_pass, 3, DAY_IN_SECONDS ); |
| 113 | setcookie('jpp_math_pass', $temp_pass, time() + DAY_IN_SECONDS, COOKIEPATH, COOKIE_DOMAIN, false); |
| 114 | remove_action( 'login_form', array( $this, 'math_form' ) ); |
| 115 | return true; |
| 116 | } |
| 117 | } |
| 118 | |
| 119 | /** |
| 120 | * Requires a user to solve a simple equation. Added to any WordPress login form. |
| 121 | * |
| 122 | * @return VOID outputs html |
| 123 | */ |
| 124 | static function math_form() { |
| 125 | // Check if jpp_math_pass cookie is set and it matches valid transient |
| 126 | if( isset( $_COOKIE[ 'jpp_math_pass' ] ) ) { |
| 127 | $jetpack_protect = Jetpack_Protect_Module::instance(); |
| 128 | $transient = $jetpack_protect->get_transient( 'jpp_math_pass_' . $_COOKIE[ 'jpp_math_pass' ] ); |
| 129 | |
| 130 | if( $transient && $transient > 0 ) { |
| 131 | return ''; |
| 132 | } |
| 133 | } |
| 134 | |
| 135 | $num1 = rand( 0, 10 ); |
| 136 | $num2 = rand( 1, 10 ); |
| 137 | $ans = $num1 + $num2; |
| 138 | |
| 139 | $time_window = Jetpack_Protect_Math_Authenticate::time_window(); |
| 140 | $salt = get_site_option( 'jetpack_protect_key' ) . '|' . get_site_option( 'admin_email' ) . '|'; |
| 141 | $salted_ans = hash_hmac( 'sha1', $ans, $salt . $time_window ); |
| 142 | ?> |
| 143 | <div style="margin: 5px 0 20px;"> |
| 144 | <label for="jetpack_protect_answer"> |
| 145 | <?php esc_html_e( 'Prove your humanity', 'jetpack' ); ?> |
| 146 | </label> |
| 147 | <br/> |
| 148 | <span style="vertical-align:super;"> |
| 149 | <?php echo esc_html( "$num1 + $num2 = " ); ?> |
| 150 | </span> |
| 151 | <input type="text" id="jetpack_protect_answer" name="jetpack_protect_num" value="" size="2" style="width:30px;height:25px;vertical-align:middle;font-size:13px;" class="input" /> |
| 152 | <input type="hidden" name="jetpack_protect_answer" value="<?php echo esc_attr( $salted_ans ); ?>" /> |
| 153 | </div> |
| 154 | <?php |
| 155 | } |
| 156 | |
| 157 | } |
| 158 | } |
| 159 |