Changeset 56493

Timestamp:

08/30/2023 03:37:33 PM (13 months ago)

Author:

Bernhard Reiter

Message:

HTML API: Stop processing HTML when encountering unsupported markup.

It was a design goal of the HTML Processor to abort processing its input document when encountering unsupported markup. Unfortunately there was no test for this and so-far, the HTML Processor has paused, but continued processing in these situations.

In this patch a new test ensures that the HTML Processor stops and refuses to move forward after encountering any unsupported markup. It also ensures that it doesn't report any current tag names since unsupported markup could imply that the read tag name is different than the parsed tag name.

Props dmsnell.
Fixes #59167.

Location:

trunk

Files:

• src/wp-includes/html-api/class-wp-html-processor.php (modified) (2 diffs)
• tests/phpunit/tests/html-api/wpHtmlProcessor.php (modified) (1 diff)

trunk/src/wp-includes/html-api/class-wp-html-processor.php

@@ -433 +433 @@
      */
     public function step( $node_to_process = self::PROCESS_NEXT_NODE ) {
+        // Refuse to proceed if there was a previous error.
+        if ( null !== $this->last_error ) {
+            return false;
+        }
+
         if ( self::PROCESS_NEXT_NODE === $node_to_process ) {
             $top_node = $this->state->stack_of_open_elements->current_node();
@@ -745 +750 @@
      */
     public function get_tag() {
+        if ( null !== $this->last_error ) {
+            return null;
+        }
+
         $tag_name = parent::get_tag();
 

trunk/tests/phpunit/tests/html-api/wpHtmlProcessor.php

@@ -41 +41 @@
             "Calling the public constructor should warn to call the static creator methods instead, but didn't."
         );
+    }
+
+    /**
+     * Once stepping to the end of the document, WP_HTML_Processor::get_tag
+     * should no longer report a tag. It should report `null` because there
+     * is no tag matched or open.
+     *
+     * @ticket 59167
+     *
+     * @covers WP_HTML_Processor::get_tag
+     */
+    public function test_get_tag_is_null_once_document_is_finished() {
+        $p = WP_HTML_Processor::createFragment( '<div class="test">Test</div>' );
+        $p->next_tag();
+        $this->assertSame( 'DIV', $p->get_tag() );
+
+        $this->assertFalse( $p->next_tag() );
+        $this->assertNull( $p->get_tag() );
+    }
+
+    /**
+     * Ensures that if the HTML Processor encounters inputs that it can't properly handle,
+     * that it stops processing the rest of the document. This prevents data corruption.
+     *
+     * @ticket 59167
+     *
+     * @covers WP_HTML_Processor::next_tag
+     */
+    public function test_stops_processing_after_unsupported_elements() {
+        $p = WP_HTML_Processor::createFragment( '<p><x-not-supported></p><p></p>' );
+        $p->next_tag( 'P' );
+        $this->assertFalse( $p->next_tag(), 'Stepped into a tag after encountering X-NOT-SUPPORTED element when it should have aborted.' );
+        $this->assertNull( $p->get_tag(), "Should have aborted processing, but still reported tag {$p->get_tag()} after properly failing to step into tag." );
+        $this->assertFalse( $p->next_tag( 'P' ), 'Stepped into normal P element after X-NOT-SUPPORTED element when it should have aborted.' );
     }