From: Sascha Greuel <sascha@softcreatr.de>
Date: Wed, 9 Sep 2020 08:03:04 +0000 (+0200)
Subject: Fix PHP 8 compatibility in GDImageAdapter (#3558)
X-Git-Tag: 5.3.0_Beta_1~7^2~9
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=26f418a40e9f9d0d45bddff51f5778c4ec72c3a1;p=GitHub%2FWoltLab%2FWCF.git

Fix PHP 8 compatibility in GDImageAdapter (#3558)

Fixed image resource validation

Resolves #3492
---

diff --git a/wcfsetup/install/files/lib/system/image/adapter/GDImageAdapter.class.php b/wcfsetup/install/files/lib/system/image/adapter/GDImageAdapter.class.php
index 6f8a873c19..ec600d89c5 100644
--- a/wcfsetup/install/files/lib/system/image/adapter/GDImageAdapter.class.php
+++ b/wcfsetup/install/files/lib/system/image/adapter/GDImageAdapter.class.php
@@ -56,11 +56,20 @@ class GDImageAdapter implements IImageAdapter {
 		@ini_set('gd.jpeg_ignore_warning', '1');
 	}
 	
+	/**
+	 * Returns whether the given image is a valid GD resource / GD object
+	 * 
+	 * @return	boolean
+	 */
+	public function isImage($image) {
+		return (is_resource($image) && get_resource_type($image) === 'gd') || (is_object($image) && $image instanceof \GdImage);
+	}
+	
 	/**
 	 * @inheritDoc
 	 */
 	public function load($image, $type = '') {
-		if (!is_resource($image)) {
+		if (!$this->isImage($image)) {
 			throw new SystemException("Image resource is invalid.");
 		}
 		
@@ -325,7 +334,7 @@ class GDImageAdapter implements IImageAdapter {
 	 * @inheritDoc
 	 */
 	public function writeImage($image, $filename) {
-		if (!is_resource($image)) {
+		if (!$this->isImage($image)) {
 			throw new SystemException("Given image is not a valid image resource.");
 		}