From c9dce0606b0d7e6f494d4abe7b193ac046a322cd Mon Sep 17 00:00:00 2001
From: John Blackbourn <johnbillion@git.wordpress.org>
Date: Thu, 5 Jul 2018 14:32:25 +0000
Subject: [PATCH] Media: Limit thumbnail file deletions to the same directory
 as the original file.

Built from https://develop.svn.wordpress.org/trunk@43392


git-svn-id: http://core.svn.wordpress.org/trunk@43220 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/functions.php | 22 ++++++++++++++
 wp-includes/post.php      | 63 +++++++++++++++++++++++++++++++--------
 wp-includes/version.php   |  2 +-
 3 files changed, 73 insertions(+), 14 deletions(-)

diff --git a/wp-includes/functions.php b/wp-includes/functions.php
index 94005d65a0..619e55304e 100644
--- a/wp-includes/functions.php
+++ b/wp-includes/functions.php
@@ -5847,6 +5847,28 @@ function wp_delete_file( $file ) {
 	}
 }
 
+/**
+ * Deletes a file if its path is within the given directory.
+ *
+ * @since 4.9.7
+ *
+ * @param string $file      Absolute path to the file to delete.
+ * @param string $directory Absolute path to a directory.
+ * @return bool True on success, false on failure.
+ */
+function wp_delete_file_from_directory( $file, $directory ) {
+	$real_file = realpath( wp_normalize_path( $file ) );
+	$real_directory = realpath( wp_normalize_path( $directory ) );
+
+	if ( false === $real_file || false === $real_directory || strpos( wp_normalize_path( $real_file ), trailingslashit( wp_normalize_path( $real_directory ) ) ) !== 0 ) {
+		return false;
+	}
+
+	wp_delete_file( $file );
+
+	return true;
+}
+
 /**
  * Outputs a small JS snippet on preview tabs/windows to remove `window.name` on unload.
  *
diff --git a/wp-includes/post.php b/wp-includes/post.php
index 3ae08c1319..ddc4fdc1d1 100644
--- a/wp-includes/post.php
+++ b/wp-includes/post.php
@@ -5311,42 +5311,79 @@ function wp_delete_attachment( $post_id, $force_delete = false ) {
 	/** This action is documented in wp-includes/post.php */
 	do_action( 'deleted_post', $post_id );
 
+	wp_delete_attachment_files( $post_id, $meta, $backup_sizes, $file );
+
+	clean_post_cache( $post );
+
+	return $post;
+}
+
+/**
+ * Deletes all files that belong to the given attachment.
+ *
+ * @since 4.9.7
+ *
+ * @param int    $post_id      Attachment ID.
+ * @param array  $meta         The attachment's meta data.
+ * @param array  $backup_sizes The meta data for the attachment's backup images.
+ * @param string $file         Absolute path to the attachment's file.
+ * @return bool True on success, false on failure.
+ */
+function wp_delete_attachment_files( $post_id, $meta, $backup_sizes, $file ) {
+	global $wpdb;
+
 	$uploadpath = wp_get_upload_dir();
+	$deleted    = true;
 
 	if ( ! empty( $meta['thumb'] ) ) {
 		// Don't delete the thumb if another attachment uses it.
 		if ( ! $wpdb->get_row( $wpdb->prepare( "SELECT meta_id FROM $wpdb->postmeta WHERE meta_key = '_wp_attachment_metadata' AND meta_value LIKE %s AND post_id <> %d", '%' . $wpdb->esc_like( $meta['thumb'] ) . '%', $post_id ) ) ) {
 			$thumbfile = str_replace( basename( $file ), $meta['thumb'], $file );
-			/** This filter is documented in wp-includes/functions.php */
-			$thumbfile = apply_filters( 'wp_delete_file', $thumbfile );
-			@ unlink( path_join( $uploadpath['basedir'], $thumbfile ) );
+			if ( ! empty( $thumbfile ) ) {
+				$thumbfile = path_join( $uploadpath['basedir'], $thumbfile );
+				$thumbdir  = path_join( $uploadpath['basedir'], dirname( $file ) );
+
+				if ( ! wp_delete_file_from_directory( $thumbfile, $thumbdir ) ) {
+					$deleted = false;
+				}
+			}
 		}
 	}
 
 	// Remove intermediate and backup images if there are any.
 	if ( isset( $meta['sizes'] ) && is_array( $meta['sizes'] ) ) {
+		$intermediate_dir = path_join( $uploadpath['basedir'], dirname( $file ) );
 		foreach ( $meta['sizes'] as $size => $sizeinfo ) {
 			$intermediate_file = str_replace( basename( $file ), $sizeinfo['file'], $file );
-			/** This filter is documented in wp-includes/functions.php */
-			$intermediate_file = apply_filters( 'wp_delete_file', $intermediate_file );
-			@ unlink( path_join( $uploadpath['basedir'], $intermediate_file ) );
+			if ( ! empty( $intermediate_file ) ) {
+				$intermediate_file = path_join( $uploadpath['basedir'], $intermediate_file );
+
+				if ( ! wp_delete_file_from_directory( $intermediate_file, $intermediate_dir ) ) {
+					$deleted = false;
+				}
+			}
 		}
 	}
 
 	if ( is_array( $backup_sizes ) ) {
+		$del_dir = path_join( $uploadpath['basedir'], dirname( $meta['file'] ) );
 		foreach ( $backup_sizes as $size ) {
 			$del_file = path_join( dirname( $meta['file'] ), $size['file'] );
-			/** This filter is documented in wp-includes/functions.php */
-			$del_file = apply_filters( 'wp_delete_file', $del_file );
-			@ unlink( path_join( $uploadpath['basedir'], $del_file ) );
+			if ( ! empty( $del_file ) ) {
+				$del_file = path_join( $uploadpath['basedir'], $del_file );
+
+				if ( ! wp_delete_file_from_directory( $del_file, $del_dir ) ) {
+					$deleted = false;
+				}
+			}
 		}
 	}
 
-	wp_delete_file( $file );
+	if ( ! wp_delete_file_from_directory( $file, $uploadpath['basedir'] ) ) {
+		$deleted = false;
+	}
 
-	clean_post_cache( $post );
-
-	return $post;
+	return $deleted;
 }
 
 /**
diff --git a/wp-includes/version.php b/wp-includes/version.php
index eaac2cd7d5..35a98623cf 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.0-alpha-43391';
+$wp_version = '5.0-alpha-43392';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.