From a271c43cdb544c6d81fe2afbcbf59dd3c6896245 Mon Sep 17 00:00:00 2001
From: Sergey Biryukov <sergeybiryukov.ru@gmail.com>
Date: Tue, 30 Jan 2018 14:44:42 +0000
Subject: [PATCH] Customize: Ensure `customize_autosaved` requests only use
 revision of logged-in user.

Props dlh, westonruter.
See #42433, #39896.
Merges [42615] to the 4.9 branch.
Fixes #42450.
Built from https://develop.svn.wordpress.org/branches/4.9@42620


git-svn-id: http://core.svn.wordpress.org/branches/4.9@42449 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/class-wp-customize-manager.php | 21 +++++++++++++++------
 wp-includes/version.php                    |  2 +-
 2 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/wp-includes/class-wp-customize-manager.php b/wp-includes/class-wp-customize-manager.php
index 6ee4271af2..99cadbd60b 100644
--- a/wp-includes/class-wp-customize-manager.php
+++ b/wp-includes/class-wp-customize-manager.php
@@ -1135,7 +1135,7 @@ final class WP_Customize_Manager {
 		if ( ! $changeset_post_id ) {
 			$this->_changeset_data = array();
 		} else {
-			if ( $this->autosaved() ) {
+			if ( $this->autosaved() && is_user_logged_in() ) {
 				$autosave_post = wp_get_post_autosave( $changeset_post_id, get_current_user_id() );
 				if ( $autosave_post ) {
 					$data = $this->get_changeset_post_data( $autosave_post->ID );
@@ -2878,10 +2878,12 @@ final class WP_Customize_Manager {
 				$post_array['edit_date'] = true; // Prevent date clearing.
 				$r = wp_update_post( wp_slash( $post_array ), true );
 
-				// Delete autosave revision when the changeset is updated.
-				$autosave_draft = wp_get_post_autosave( $changeset_post_id, get_current_user_id() );
-				if ( $autosave_draft ) {
-					wp_delete_post( $autosave_draft->ID, true );
+				// Delete autosave revision for user when the changeset is updated.
+				if ( ! empty( $args['user_id'] ) ) {
+					$autosave_draft = wp_get_post_autosave( $changeset_post_id, $args['user_id'] );
+					if ( $autosave_draft ) {
+						wp_delete_post( $autosave_draft->ID, true );
+					}
 				}
 			}
 		} else {
@@ -3493,6 +3495,11 @@ final class WP_Customize_Manager {
 	 * @since 4.9.0
 	 */
 	public function handle_dismiss_autosave_or_lock_request() {
+		// Calls to dismiss_user_auto_draft_changesets() and wp_get_post_autosave() require non-zero get_current_user_id().
+		if ( ! is_user_logged_in() ) {
+			wp_send_json_error( 'unauthenticated', 401 );
+		}
+
 		if ( ! $this->is_preview() ) {
 			wp_send_json_error( 'not_preview', 400 );
 		}
@@ -4574,7 +4581,9 @@ final class WP_Customize_Manager {
 		$changeset_post_id = $this->changeset_post_id();
 		if ( ! $this->saved_starter_content_changeset && ! $this->autosaved() ) {
 			if ( $changeset_post_id ) {
-				$autosave_revision_post = wp_get_post_autosave( $changeset_post_id, get_current_user_id() );
+				if ( is_user_logged_in() ) {
+					$autosave_revision_post = wp_get_post_autosave( $changeset_post_id, get_current_user_id() );
+				}
 			} else {
 				$autosave_autodraft_posts = $this->get_changeset_posts( array(
 					'posts_per_page' => 1,
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 1743bd97f8..2e16a4f0e5 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.9.3-beta1-42609';
+$wp_version = '4.9.3-beta1-42620';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.