Changeset 54802

Timestamp:

11/11/2022 12:59:20 AM (2 years ago)

Author:

peterwilsoncc

Message:

Media: Prevent decoding attribute corrupting JSON data.

Workaround wp_img_tag_add_decoding_attr() potentially breaking JavaScript and JSON data by limiting the addition of the decoding attribute to image tags using unescaped double quoted attributes src attributes.

Props rodricus, TimothyBlynJacobs, joelmadigan, mw108, adamsilverstein, flixos90, desrosj, mukesh27.
Fixes #56969.

Location:

trunk

Files:

• src/wp-includes/media.php (modified) (1 diff)
• tests/phpunit/tests/media.php (modified) (1 diff)

trunk/src/wp-includes/media.php

@@ -1963 +1963 @@
  */
 function wp_img_tag_add_decoding_attr( $image, $context ) {
+    // Only apply the decoding attribute to images that have a src attribute that
+    // starts with a double quote, ensuring escaped JSON is also excluded.
+    if ( false === strpos( $image, ' src="' ) ) {
+        return $image;
+    }
+
     /**
      * Filters the `decoding` attribute value to add to an image. Default `async`.

trunk/tests/phpunit/tests/media.php

@@ -3164 +3164 @@
 
     /**
+     * Test that decoding="async" is not applied to img tags with single quotes.
+     *
+     * @ticket 56969
+     */
+    public function test_wp_img_tag_add_decoding_attr_with_single_quotes() {
+        $img = "<img src='example.png' alt='' width='300' height='225' />";
+        $img = wp_img_tag_add_decoding_attr( $img, 'test' );
+        $this->assertStringNotContainsString( ' decoding="async"', $img );
+    }
+
+    /**
+     * Test that decoding="async" is not applied to img tags inside JSON.
+     *
+     * @ticket 56969
+     */
+    public function test_decoding_async_not_applied_to_json() {
+        $content = '{"image": "<img src=\"example.png\" alt=\"\" width=\"300\" height=\"225\" />"}';
+        $content = wp_filter_content_tags( $content );
+        $this->assertStringNotContainsString( ' decoding="async"', $content );
+    }
+
+    /**
      * @ticket 50756
      */