From 3e77adc6196383091254fbc562a4b2ecc39e71ee Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@git.wordpress.org>
Date: Tue, 19 Sep 2017 14:37:33 +0000
Subject: [PATCH] Filesystem API: Ensure filenames are valid before attempting
 to unzip them to ensure malformed file paths don't cause issues.

Merges [41457] to the 4.8 branch.

Built from https://develop.svn.wordpress.org/branches/4.8@41458


git-svn-id: http://core.svn.wordpress.org/branches/4.8@41291 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-admin/includes/file.php | 8 ++++++++
 wp-includes/version.php    | 2 +-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/wp-admin/includes/file.php b/wp-admin/includes/file.php
index b1f447ea62..3d1a07aaaf 100644
--- a/wp-admin/includes/file.php
+++ b/wp-admin/includes/file.php
@@ -647,6 +647,10 @@ function _unzip_file_ziparchive($file, $to, $needed_dirs = array() ) {
 		if ( '__MACOSX/' === substr($info['name'], 0, 9) ) // Skip the OS X-created __MACOSX directory
 			continue;
 
+		if ( 0 !== validate_file( $info['name'] ) ) {
+			return new WP_Error( 'invalid_file_ziparchive', __( 'Could not extract file from archive.' ), $info['name'] );
+		}
+
 		$uncompressed_size += $info['size'];
 
 		if ( '/' === substr( $info['name'], -1 ) ) {
@@ -807,6 +811,10 @@ function _unzip_file_pclzip($file, $to, $needed_dirs = array()) {
 		if ( '__MACOSX/' === substr($file['filename'], 0, 9) ) // Don't extract the OS X-created __MACOSX directory files
 			continue;
 
+		if ( 0 !== validate_file( $file['filename'] ) ) {
+			return new WP_Error( 'invalid_file_pclzip', __( 'Could not extract file from archive.' ), $file['filename'] );
+		}
+
 		if ( ! $wp_filesystem->put_contents( $to . $file['filename'], $file['content'], FS_CHMOD_FILE) )
 			return new WP_Error( 'copy_failed_pclzip', __( 'Could not copy file.' ), $file['filename'] );
 	}
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 4654dd3f84..ec443a601a 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.8.2-alpha-41450';
+$wp_version = '4.8.2-alpha-41458';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.