From ef7326129fae25dd79f56ac9cf08a19165d98342 Mon Sep 17 00:00:00 2001
From: Andrew Ozz <admin@laptoptips.ca>
Date: Mon, 16 Dec 2019 23:44:04 +0000
Subject: [PATCH] Upload: Fix the final file name collision test in
 `wp_unique_filename()` when uploading a file with upper case extension. Add a
 unit test to catch that in the future.

Fixes #48975 for trunk.

Built from https://develop.svn.wordpress.org/trunk@46966


git-svn-id: http://core.svn.wordpress.org/trunk@46766 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/functions.php | 16 +++++++++++++---
 wp-includes/version.php   |  2 +-
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/wp-includes/functions.php b/wp-includes/functions.php
index 4cc62be66d..6a7b16563d 100644
--- a/wp-includes/functions.php
+++ b/wp-includes/functions.php
@@ -2410,6 +2410,7 @@ function _wp_upload_dir( $time = null ) {
 function wp_unique_filename( $dir, $filename, $unique_filename_callback = null ) {
 	// Sanitize the file name before we begin processing.
 	$filename = sanitize_file_name( $filename );
+	$ext2     = null;
 
 	// Separate the filename into a name and extension.
 	$ext  = pathinfo( $filename, PATHINFO_EXTENSION );
@@ -2485,10 +2486,19 @@ function wp_unique_filename( $dir, $filename, $unique_filename_callback = null )
 			}
 
 			if ( ! empty( $files ) ) {
-				while ( _wp_check_existing_file_names( $filename, $files ) ) {
+				// The extension case may have changed above.
+				$new_ext = ! empty( $ext2 ) ? $ext2 : $ext;
+
+				// Ensure this never goes into infinite loop
+				// as it uses pathinfo() and regex in the check but string replacement for the changes.
+				$count = count( $files );
+				$i     = 1;
+
+				while ( $i <= $count && _wp_check_existing_file_names( $filename, $files ) ) {
 					$new_number = (int) $number + 1;
-					$filename   = str_replace( array( "-{$number}{$ext}", "{$number}{$ext}" ), "-{$new_number}{$ext}", $filename );
+					$filename   = str_replace( array( "-{$number}{$new_ext}", "{$number}{$new_ext}" ), "-{$new_number}{$new_ext}", $filename );
 					$number     = $new_number;
+					$i++;
 				}
 			}
 		}
@@ -2530,7 +2540,7 @@ function _wp_check_existing_file_names( $filename, $files ) {
 		$ext = ".$ext";
 	}
 
-	$regex = '/^' . preg_quote( $fname ) . '-(?:\d+x\d+|scaled|rotated)' . preg_quote( $ext ) . '$/';
+	$regex = '/^' . preg_quote( $fname ) . '-(?:\d+x\d+|scaled|rotated)' . preg_quote( $ext ) . '$/i';
 
 	foreach ( $files as $file ) {
 		if ( preg_match( $regex, $file ) ) {
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 86b812d71d..4f6fa7089c 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.4-alpha-46965';
+$wp_version = '5.4-alpha-46966';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.