Merge branch 'captcha-workaround' into 'config'

Captcha workaround

See merge request leftypol/leftypol!9

inc/config.php

@@ -301,9 +301,8 @@
         'lock',
         'raw',
         'embed',
-        'g-recaptcha-response',
+        'captcha-response',
-        'h-captcha-response',
+        'captcha-form-id',
-        'cf-turnstile-response',
         'spoiler',
         'page',
         'file_url',
@@ -330,33 +329,40 @@
             'answer' => '4'
         );
     */
-    /**
+    // Enable a captcha system to make spam even harder. Rarely necessary.
-     * The captcha is dynamically injected on the client if the server replies with the `captcha-required` cookie set
+    $config['captcha'] = [
-     * to 1.
+        /**
-     * Use false to disable this configuration, otherwise, set the IP that vichan should check for captcha responses.
+         * Select the captcha backend, false to disable.
-     */
+         * Can be false, "recaptcha", "hcaptcha" or "turnstile".
-    $config['dynamic_captcha'] = false;
+         */
-
+        'mode' => false,
-    // Enable reCaptcha to make spam even harder. Rarely necessary.
+        /**
-    $config['recaptcha'] = false;
+         * The captcha is dynamically injected on the client if the server replies with the `captcha-required` cookie set
-
+         * to 1.
-    // Public and private key pair from https://www.google.com/recaptcha/admin/create
+         * Use false to disable this configuration, otherwise, set the IP that vichan should check for captcha responses.
-    $config['recaptcha_public'] = '6LcXTcUSAAAAAKBxyFWIt2SO8jwx4W7wcSMRoN3f';
+         */
-    $config['recaptcha_private'] = '6LcXTcUSAAAAAOGVbVdhmEM1_SyRF4xTKe8jbzf_';
+        'dynamic' => false,
-
+        // Require to be non-zero if you use js/ajax.js (preferably no more than a few seconds), otherwise weird errors might occur.
-    // Enable hCaptcha.
+        'passthrough_timeout' => 0,
-    $config['hcaptcha'] = false;
+        // Configure Google reCAPTCHA.
-
+        'recaptcha' => [
-    // Public and private key pair for using hCaptcha.
+            // Public and private key pair from https://www.google.com/recaptcha/admin/create
-    $config['hcaptcha_public'] = '7a4b21e0-dc53-46f2-a9f8-91d2e74b63a0';
+            'public' => '6LcXTcUSAAAAAKBxyFWIt2SO8jwx4W7wcSMRoN3f',
-    $config['hcaptcha_private'] = '0x4e9A01bE637b51dC41a7Ea9865C3fDe4aB72Cf17';
+            'private' => '6LcXTcUSAAAAAOGVbVdhmEM1_SyRF4xTKe8jbzf_',
-
+        ],
-    // Enable Cloudflare's Turnstile captcha.
+        // Configure hCaptcha.
-    $config['turnstile'] = false;
+        'hcaptcha' => [
-
+            // Public and private key pair for using hCaptcha.
-    // Public and private key pair for turnstile.
+            'public' => '7a4b21e0-dc53-46f2-a9f8-91d2e74b63a0',
-    $config['turnstile_public'] = '';
+            'private' => '0x4e9A01bE637b51dC41a7Ea9865C3fDe4aB72Cf17',
-    $config['turnstile_private'] = '';
+        ],
+        // Configure Cloudflare Turnstile.
+        'turnstile' => [
+            // Public and private key pair for turnstile.
+            'public' => '',
+            'private' => '',
+        ]
+    ];
 
     // Ability to lock a board for normal users and still allow mods to post.  Could also be useful for making an archive board
     $config['board_locked'] = false;

post.php

@@ -167,6 +167,68 @@ function check_turnstile($secret, $response, $remote_ip, $expected_action)
     return $json_ret['success'] === true && $json_ret['action'] === $expected_action;
 }
 
+/**
+ * A "sophisticated" workaround to js/ajax.js calling post.php multiple times on error/ban.
+ */
+function check_captcha(array $captcha_config, string $form_id, string $board_uri, string $response, string $remote_ip, string $expected_action) {
+    $dynamic = $captcha_config['dynamic'];
+    if ($dynamic !== false && $remote_ip !== $dynamic) {
+        return true;
+    }
+
+    switch ($captcha_config['mode']) {
+        case 'recaptcha':
+        case 'hcaptcha':
+        case 'turnstile':
+            $mode = $captcha_config['mode'];
+            break;
+        case false:
+            return true;
+        default:
+            \error_log("Unknown captcha mode '{$captcha_config['mode']}'");
+            throw new \RuntimeException('Captcha configuration error');
+    }
+
+    $passthrough_timeout = $captcha_config['passthrough_timeout'];
+
+    if ($passthrough_timeout != 0) {
+        $pass = Cache::get("captcha_passthrough_{$remote_ip}_{$form_id}");
+        if ($pass !== false) {
+            $let_through = $pass['expires'] > time() && $pass['board_uri'] === $board_uri && $pass['captcha_response'] === $response;
+            if ($let_through) {
+                return true;
+            }
+        }
+    }
+
+    $remote_ip_send = $dynamic !== false ? null : $remote_ip;
+    $private_key = $captcha_config[$mode]['private'];
+    $public_key = $captcha_config[$mode]['public'];
+    switch ($mode) {
+        case 'recaptcha':
+            $ret = check_recaptcha($private_key, $response, $remote_ip_send);
+            break;
+        case 'hcaptcha':
+            $ret = check_hcaptcha($private_key, $response, $remote_ip_send, $public_key);
+            break;
+        case 'turnstile':
+            $ret = check_turnstile($private_key, $response, $remote_ip_send, $expected_action);
+            break;
+    }
+
+    if ($ret && $passthrough_timeout != 0) {
+        $pass = [
+            'expires' => time() + $passthrough_timeout,
+            'board_uri' => $board_uri,
+            'captcha_response' => $response
+        ];
+
+        Cache::set("captcha_passthrough_{$remote_ip}_{$form_id}", $pass, $passthrough_timeout + 2);
+    }
+
+    return $ret;
+}
+
 /**
  * Deletes the (single) captcha associated with the ip and code.
  *
@@ -765,56 +827,16 @@ function handle_post()
 
 
     if (!$dropped_post) {
-        if ($config['dynamic_captcha'] !== false) {
+        // Check for CAPTCHA right after opening the board so the "return" link is in there.
-            if ($_SERVER['REMOTE_ADDR'] === $config['dynamic_captcha']) {
+        if ($config['captcha']['mode'] !== false) {
-                if ($config['recaptcha']) {
+            if (!isset($_POST['captcha-response'], $_POST['captcha-form-id'])) {
-                    if (!isset($_POST['g-recaptcha-response'])) {
+                error($config['error']['bot']);
-                        error($config['error']['bot']);
-                    }
-                    if (!check_recaptcha($config['recaptcha_private'], $_POST['g-recaptcha-response'], null)) {
-                        error($config['error']['captcha']);
-                    }
-                } elseif ($config['hcaptcha']) {
-                    if (!isset($_POST['h-captcha-response'])) {
-                        error($config['error']['bot']);
-                    }
-                    if (!check_hcaptcha($config['hcaptcha_private'], $_POST['h-captcha-response'], null, $config['hcaptcha_public'])) {
-                        error($config['error']['captcha']);
-                    }
-                } elseif ($config['turnstile']) {
-                    if (!isset($_POST['cf-turnstile-response'])) {
-                        error($config['error']['bot']);
-                    }
-                    $expected_action = $post['op'] ? 'post-thread' : 'post-reply';
-                    if (!check_turnstile($config['turnstile_private'], $_POST['cf-turnstile-response'], null, $expected_action)) {
-                        error($config['error']['captcha']);
-                    }
-                }
             }
-        } else {
+
-            // Check for CAPTCHA right after opening the board so the "return" link is in there.
+            $expected_action = $post['op'] ? 'post-thread' : 'post-reply';
-            if ($config['recaptcha']) {
+            $ret = check_captcha($config['captcha'], $_POST['captcha-form-id'], $post['board'], $_POST['captcha-response'], $_SERVER['REMOTE_ADDR'], $expected_action);
-                if (!isset($_POST['g-recaptcha-response'])) {
+            if (!$ret) {
-                    error($config['error']['bot']);
+                error($config['error']['captcha']);
-                }
-                if (!check_recaptcha($config['recaptcha_private'], $_POST['g-recaptcha-response'], $_SERVER['REMOTE_ADDR'])) {
-                    error($config['error']['captcha']);
-                }
-            } elseif ($config['hcaptcha']) {
-                if (!isset($_POST['h-captcha-response'])) {
-                    error($config['error']['bot']);
-                }
-                if (!check_hcaptcha($config['hcaptcha_private'], $_POST['h-captcha-response'], $_SERVER['REMOTE_ADDR'], $config['hcaptcha_public'])) {
-                    error($config['error']['captcha']);
-                }
-            } elseif ($config['turnstile']) {
-                if (!isset($_POST['cf-turnstile-response'])) {
-                    error($config['error']['bot']);
-                }
-                $expected_action = $post['op'] ? 'post-thread' : 'post-reply';
-                if (!check_turnstile($config['turnstile_private'], $_POST['cf-turnstile-response'], null, $expected_action)) {
-                    error($config['error']['captcha']);
-                }
             }
         }
 

templates/main.js

@@ -273,8 +273,9 @@ var captcha_renderer = null;
 function onCaptchaLoadHcaptcha() {
 	if (captcha_renderer === null && (active_page === 'index' || active_page === 'catalog' || active_page === 'thread')) {
 		let renderer = {
-			renderOn: (container) => hcaptcha.render(container, {
+			applyOn: (container, params) => hcaptcha.render(container, {
 				sitekey: "{{ config.hcaptcha_public }}",
+				callback: params['on-success'],
 			}),
 			remove: (widgetId) => { /* Not supported */ },
 			reset: (widgetId) => hcaptcha.reset(widgetId)
@@ -300,10 +301,11 @@ window.onCaptchaLoadTurnstile_post_thread = function() {
 function onCaptchaLoadTurnstile(action) {
 	if (captcha_renderer === null && (active_page === 'index' || active_page === 'catalog' || active_page === 'thread')) {
 		let renderer = {
-			renderOn: function(container) {
+			applyOn: function(container, params) {
 				let widgetId = turnstile.render('#' + container, {
 					sitekey: "{{ config.turnstile_public }}",
 					action: action,
+					callback: params['on-success'],
 				});
 				if (widgetId === undefined) {
 					return null;
@@ -320,9 +322,16 @@ function onCaptchaLoadTurnstile(action) {
 {% endif %} // End if turnstile
 
 function onCaptchaLoad(renderer) {
+	// Initialize the form identifier with a random password.
+	document.getElementById('captcha-form-id').value = generatePassword();
+
 	captcha_renderer = renderer;
 
-	let widgetId = renderer.renderOn('captcha-container');
+	let widgetId = renderer.applyOn('captcha-container', {
+		'on-success': function(token) {
+			document.getElementById('captcha-response').value = token;
+		}
+	});
 	if (widgetId === null) {
 		console.error('Could not render captcha!');
 	}

templates/post_form.html

@@ -118,6 +118,8 @@
 			</th>
 			<td>
 				<div id="captcha-container"></div>
+				<textarea id="captcha-response" name="captcha-response" style="display:none;"></textarea>
+				<textarea id="captcha-form-id" name="captcha-form-id" style="display:none;"></textarea>
 				{{ antibot.html() }}
 			</td>
 		</tr>