From 1dcdbc9d60a2f00f3dd1ab9e7a7573701fb847b4 Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@git.wordpress.org>
Date: Tue, 19 Sep 2017 14:38:01 +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 4.7 branch.


git-svn-id: https://develop.svn.wordpress.org/branches/4.7@41459 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-admin/includes/file.php | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/wp-admin/includes/file.php b/src/wp-admin/includes/file.php
index 872cf9bce2..0de5ba5249 100644
--- a/src/wp-admin/includes/file.php
+++ b/src/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'] );
 	}