From f9bbe30683824b1dcaa3543e34e29f5a31aaaf7b Mon Sep 17 00:00:00 2001
From: Weston Ruter <weston@xwp.co>
Date: Wed, 23 May 2018 14:39:06 -0700
Subject: [PATCH] Ensure that AMP HTML is not removed via Kses when
 unfiltered_html absent

---
 includes/admin/class-amp-editor-blocks.php | 56 ++++++++++++++++++++--
 1 file changed, 52 insertions(+), 4 deletions(-)

diff --git a/includes/admin/class-amp-editor-blocks.php b/includes/admin/class-amp-editor-blocks.php
index 857de04fe66..b847e2362fd 100644
--- a/includes/admin/class-amp-editor-blocks.php
+++ b/includes/admin/class-amp-editor-blocks.php
@@ -17,21 +17,69 @@ class AMP_Editor_Blocks {
 	public function init() {
 		if ( function_exists( 'gutenberg_init' ) ) {
 			add_action( 'enqueue_block_editor_assets', array( $this, 'enqueue_block_editor_assets' ) );
-			add_filter( 'wp_kses_allowed_html', array( $this, 'whitelist_block_atts_in_wp_kses_allowed_html' ), 10 );
+			add_filter( 'wp_kses_allowed_html', array( $this, 'whitelist_block_atts_in_wp_kses_allowed_html' ), 10, 2 );
 		}
 	}
 
 	/**
-	 * Whitelist used data-amp-* attributes.
+	 * Whitelist elements and attributes used for AMP.
 	 *
-	 * @param array $tags Array of allowed post tags.
+	 * This prevents AMP markup from being deleted in
+	 *
+	 * @param array  $tags    Array of allowed post tags.
+	 * @param string $context Context.
 	 * @return mixed Modified array.
 	 */
-	public function whitelist_block_atts_in_wp_kses_allowed_html( $tags ) {
+	public function whitelist_block_atts_in_wp_kses_allowed_html( $tags, $context ) {
+		if ( 'post' !== $context ) {
+			return $tags;
+		}
+
 		foreach ( $tags as &$tag ) {
 			$tag['data-amp-layout']    = true;
 			$tag['data-amp-noloading'] = true;
 		}
+
+		$amp_blocks = array(
+			'amp-mathml',
+			'amp-o2-player',
+			'amp-ooyala-player',
+			'amp-reach-player',
+			'amp-springboard-player',
+			'amp-jwplayer',
+			'amp-brid-player',
+			'amp-ima-video',
+		);
+
+		foreach ( $amp_blocks as $amp_block ) {
+			if ( ! isset( $tags[ $amp_block ] ) ) {
+				$tags[ $amp_block ] = array();
+			}
+
+			$tags[ $amp_block ] = array_merge(
+				array_fill_keys(
+					array(
+						'layout',
+						'width',
+						'height',
+					),
+					true
+				),
+				$tags[ $amp_block ]
+			);
+
+			$amp_tag_specs = AMP_Allowed_Tags_Generated::get_allowed_tag( $amp_block );
+			foreach ( $amp_tag_specs as $amp_tag_spec ) {
+				if ( ! isset( $amp_tag_spec[ AMP_Rule_Spec::ATTR_SPEC_LIST ] ) ) {
+					continue;
+				}
+				$tags[ $amp_block ] = array_merge(
+					$tags[ $amp_block ],
+					array_fill_keys( array_keys( $amp_tag_spec[ AMP_Rule_Spec::ATTR_SPEC_LIST ] ), true )
+				);
+			}
+		}
+
 		return $tags;
 	}