jetpack / modules / protect / math-fallback.php

math-fallback.php in Jetpack – WP Security, Backup, Speed, & Growth 10.4, at modules/protect/math-fallback.php

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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	wp_kses(
61	__(
62	'<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.',
63	'jetpack'
64	),
65	array( 'strong' => array() )
66	),
67	'',
68	array( 'response' => 401 )
69	);
70	} else {
71	return true;
72	}
73	}
74
75	/**
76	* Creates an interim page to collect answers to a math captcha
77	*
78	* @return none, execution stopped
79	*/
80	static function generate_math_page( $error = false ) {
81	ob_start();
82	?>
83	<h2><?php esc_html_e( 'Please solve this math problem to prove that you are not a bot. Once you solve it, you will need to log in again.', 'jetpack' ); ?></h2>
84	<?php if ($error): ?>
85	<h3><?php esc_html_e( 'Your answer was incorrect, please try again.', 'jetpack' ); ?></h3>
86	<?php endif ?>
87
88	<form action="<?php echo wp_login_url(); ?>" method="post" accept-charset="utf-8">
89	<?php Jetpack_Protect_Math_Authenticate::math_form(); ?>
90	<input type="hidden" name="jetpack_protect_process_math_form" value="1" id="jetpack_protect_process_math_form" />
91	<p><input type="submit" value="<?php esc_attr_e( 'Continue →', 'jetpack' ); ?>"></p>
92	</form>
93	<?php
94	$mathpage = ob_get_contents();
95	ob_end_clean();
96	wp_die(
97	$mathpage,
98	'',
99	array ( 'response' => 401 )
100	);
101	}
102
103	public function process_generate_math_page() {
104	$ans = isset( $_POST['jetpack_protect_num'] ) ? (int)$_POST['jetpack_protect_num'] : '';
105	$correct_ans = isset( $_POST[ 'jetpack_protect_answer' ] ) ? $_POST[ 'jetpack_protect_answer' ] : '' ;
106
107	$time_window = Jetpack_Protect_Math_Authenticate::time_window();
108	$salt = get_site_option( 'jetpack_protect_key' ) . '\|' . get_site_option( 'admin_email' ) . '\|';
109	$salted_ans_1 = hash_hmac( 'sha1', $ans, $salt . $time_window );
110	$salted_ans_2 = hash_hmac( 'sha1', $ans, $salt . ( $time_window - 1 ) );
111
112	if ( ! hash_equals( $salted_ans_1, $correct_ans ) && ! hash_equals( $salted_ans_2, $correct_ans ) ) {
113	Jetpack_Protect_Math_Authenticate::generate_math_page(true);
114	} else {
115	$temp_pass = substr( hash_hmac( 'sha1', rand( 1, 100000000 ), get_site_option( 'jetpack_protect_key' ) ), 5, 25 );
116
117	$jetpack_protect = Jetpack_Protect_Module::instance();
118	$jetpack_protect->set_transient( 'jpp_math_pass_' . $temp_pass, 3, DAY_IN_SECONDS );
119	setcookie('jpp_math_pass', $temp_pass, time() + DAY_IN_SECONDS, COOKIEPATH, COOKIE_DOMAIN, false);
120	remove_action( 'login_form', array( $this, 'math_form' ) );
121	return true;
122	}
123	}
124
125	/**
126	* Requires a user to solve a simple equation. Added to any WordPress login form.
127	*
128	* @return VOID outputs html
129	*/
130	static function math_form() {
131	// Check if jpp_math_pass cookie is set and it matches valid transient
132	if( isset( $_COOKIE[ 'jpp_math_pass' ] ) ) {
133	$jetpack_protect = Jetpack_Protect_Module::instance();
134	$transient = $jetpack_protect->get_transient( 'jpp_math_pass_' . $_COOKIE[ 'jpp_math_pass' ] );
135
136	if( $transient && $transient > 0 ) {
137	return '';
138	}
139	}
140
141	$num1 = rand( 0, 10 );
142	$num2 = rand( 1, 10 );
143	$ans = $num1 + $num2;
144
145	$time_window = Jetpack_Protect_Math_Authenticate::time_window();
146	$salt = get_site_option( 'jetpack_protect_key' ) . '\|' . get_site_option( 'admin_email' ) . '\|';
147	$salted_ans = hash_hmac( 'sha1', $ans, $salt . $time_window );
148	?>
149	<div style="margin: 5px 0 20px;">
150	<label for="jetpack_protect_answer">
151	<?php esc_html_e( 'Prove your humanity', 'jetpack' ); ?>
152	</label>
153	<br/>
154	<span style="vertical-align:super;">
155	<?php echo esc_html( "$num1   +   $num2   =  " ); ?>
156	</span>
157	<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" />
158	<input type="hidden" name="jetpack_protect_answer" value="<?php echo esc_attr( $salted_ans ); ?>" />
159	</div>
160	<?php
161	}
162
163	}
164	}
165