Changeset 7745

Timestamp:

10/18/2018 09:57:25 PM (6 years ago)

Author:

iandunn

Message:

WordCamp Payments: Obscure payment file names to prevent scraping.

See #3244

File:

• sites/trunk/wordcamp.org/public_html/wp-content/plugins/wordcamp-payments/includes/privacy.php (modified) (2 diffs)

sites/trunk/wordcamp.org/public_html/wp-content/plugins/wordcamp-payments/includes/privacy.php

@@ -11 +11 @@
 
 add_filter( 'the_posts',                          __NAMESPACE__ . '\hide_others_payment_files', 10, 2 );
+add_filter( 'wp_unique_filename',                 __NAMESPACE__ . '\obscure_payment_file_names', 10, 2 );
 add_filter( 'wp_privacy_personal_data_exporters', __NAMESPACE__ . '\register_personal_data_exporters' );
 add_filter( 'wp_privacy_personal_data_erasers',   __NAMESPACE__ . '\register_personal_data_erasers'   );
@@ -95 +96 @@
 
     return wp_list_pluck( $payment_posts_with_attachments, 'ID' );
+}
+
+/**
+ * Add a CSPRN to payment file names to protect privacy.
+ *
+ * Without this, a 3rd party could scrape the site looking for predictable filenames. With this added, that is no
+ * longer practical. See https://core.trac.wordpress.org/ticket/43546#comment:34 for details on how a similar
+ * technique was used in Core. A length of `16` was chosen because that makes the filename less cumbersome, but
+ * still makes brute force practically impossible (2.267522912 * 10^26 years).
+ *
+ * @param string $filename
+ * @param string $extension
+ *
+ * @return string
+ */
+function obscure_payment_file_names( $filename, $extension ) {
+    $attached_post       = get_post( absint( $_REQUEST['post_id'] ?? 0 ) );
+    $relevant_post_types = array(
+        Reimbursement_Requests\POST_TYPE,
+        WCP_Payment_Request::POST_TYPE,
+    );
+
+    if ( $attached_post instanceof WP_Post && in_array( $attached_post->post_type, $relevant_post_types, true ) ) {
+        $filename = sprintf(
+            '%s-%s%s',
+            str_replace( $extension, '', $filename ),
+            wp_generate_password( 16, false, false ),
+            $extension
+        );
+    }
+
+    return $filename;
 }