init

wp-content/plugins/mailpoet/lib/Util/Security.php

@@ -0,0 +1,97 @@
+<?php // phpcs:ignore SlevomatCodingStandard.TypeHints.DeclareStrictTypes.DeclareStrictTypesMissing
+
+namespace MailPoet\Util;
+
+if (!defined('ABSPATH')) exit;
+
+
+use Exception;
+use MailPoet\Entities\NewsletterEntity;
+use MailPoet\Entities\SubscriberEntity;
+use MailPoet\Newsletter\NewslettersRepository;
+use MailPoet\Subscribers\SubscribersRepository;
+
+class Security {
+  const HASH_LENGTH = 12;
+  const UNSUBSCRIBE_TOKEN_LENGTH = 15;
+
+  /** @var NewslettersRepository */
+  private $newslettersRepository;
+
+  /** @var SubscribersRepository */
+  private $subscribersRepository;
+
+  public function __construct(
+    NewslettersRepository $newslettersRepository,
+    SubscribersRepository $subscribersRepository
+  ) {
+    $this->newslettersRepository = $newslettersRepository;
+    $this->subscribersRepository = $subscribersRepository;
+  }
+
+  /**
+   * Generate random lowercase alphanumeric string.
+   * 1 lowercase alphanumeric character = 6 bits (because log2(36) = 5.17)
+   * So 3 bytes = 4 characters
+   * @param int $length Minimal lenght is 5
+   * @return string
+   */
+  public static function generateRandomString($length = 5): string {
+    $length = max(5, (int)$length);
+    $string = base_convert(
+      bin2hex(
+        random_bytes( // phpcs:ignore
+          (int)ceil(3 * $length / 4)
+        )
+      ),
+      16,
+      36
+    );
+    $result = substr($string, 0, $length);
+    if (strlen($result) === $length) return $result;
+    // in very rare occasions we generate a shorter string when random_bytes generates something starting with 0 let's try again
+    return self::generateRandomString($length);
+  }
+
+  /**
+   * @param int $length Maximal length is 32
+   * @return string
+   */
+  public static function generateHash($length = null) {
+    $length = ($length) ? $length : self::HASH_LENGTH;
+    $authKey = self::generateRandomString(64);
+    if (defined('AUTH_KEY')) {
+      $authKey = AUTH_KEY;
+    }
+    return substr(
+      hash_hmac('sha512', self::generateRandomString(64), $authKey),
+      0,
+      $length
+    );
+  }
+
+  static public function generateUnsubscribeToken($model) {
+    do {
+      $token = self::generateRandomString(self::UNSUBSCRIBE_TOKEN_LENGTH);
+      $found = $model::whereEqual('unsubscribe_token', $token)->count();
+    } while ($found > 0);
+    return $token;
+  }
+
+  public function generateUnsubscribeTokenByEntity($entity): string {
+    $repository = null;
+    if ($entity instanceof NewsletterEntity) {
+      $repository = $this->newslettersRepository;
+    } elseif ($entity instanceof SubscriberEntity) {
+      $repository = $this->subscribersRepository;
+    } else {
+      throw new Exception('Unsupported Entity type');
+    }
+
+    do {
+      $token = self::generateRandomString(self::UNSUBSCRIBE_TOKEN_LENGTH);
+      $found = count($repository->findBy(['unsubscribeToken' => $token]));
+    } while ($found > 0);
+    return $token;
+  }
+}