From: Joshua Rüsweg <josh@bastelstu.be>
Date: Tue, 5 Feb 2019 10:59:50 +0000 (+0100)
Subject: Add static function to check, whether a given file is an image
X-Git-Tag: 5.2.0_Alpha_1~296^2~5
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=3e7abe561f223b04ddcdabcac4df5d964f1eefb7;p=GitHub%2FWoltLab%2FWCF.git

Add static function to check, whether a given file is an image
See #2825
---

diff --git a/wcfsetup/install/files/lib/action/AJAXFileUploadAction.class.php b/wcfsetup/install/files/lib/action/AJAXFileUploadAction.class.php
index b8dfbfd918..d04d16bf83 100644
--- a/wcfsetup/install/files/lib/action/AJAXFileUploadAction.class.php
+++ b/wcfsetup/install/files/lib/action/AJAXFileUploadAction.class.php
@@ -87,24 +87,8 @@ class AJAXFileUploadAction extends AbstractSecureAction {
 		$field = UploadHandler::getInstance()->getFieldByInternalId($this->internalId);
 		
 		foreach ($_FILES['__files']['tmp_name'] as $id => $tmpName) {
-			if ($field->isImageOnly()) {
+			if ($field->isImageOnly() && !UploadHandler::isValidImage($tmpName, $_FILES['__files']['name'][$id], $field->svgImageAllowed())) {
 				if (@getimagesize($tmpName) === false) {
-					if (!$field->svgImageAllowed() || !in_array(FileUtil::getMimeType($tmpName), [
-							'image/svg',
-							'image/svg+xml'
-						])) {
-						$response['error'][$i++] = [
-							'filename' => $_FILES['__files']['name'][$id],
-							'errorMessage' => WCF::getLanguage()->get('wcf.upload.error.noImage')
-						];
-						continue;
-					}
-				}
-				
-				$allowedExtensions = ['jpeg', 'jpg', 'png', 'gif'];
-				if ($field->svgImageAllowed()) $allowedExtensions[] = 'svg';
-				
-				if (!in_array(pathinfo($_FILES['__files']['name'][$id], PATHINFO_EXTENSION), $allowedExtensions)) {
 					$response['error'][$i++] = [
 						'filename' => $_FILES['__files']['name'][$id],
 						'errorMessage' => WCF::getLanguage()->get('wcf.upload.error.noImage')
diff --git a/wcfsetup/install/files/lib/system/file/upload/UploadHandler.class.php b/wcfsetup/install/files/lib/system/file/upload/UploadHandler.class.php
index e71187b0f7..69a07cb518 100644
--- a/wcfsetup/install/files/lib/system/file/upload/UploadHandler.class.php
+++ b/wcfsetup/install/files/lib/system/file/upload/UploadHandler.class.php
@@ -3,6 +3,7 @@ namespace wcf\system\file\upload;
 use wcf\system\exception\ImplementationException;
 use wcf\system\SingletonFactory;
 use wcf\system\WCF;
+use wcf\util\FileUtil;
 use wcf\util\StringUtil;
 
 /**
@@ -21,6 +22,12 @@ class UploadHandler extends SingletonFactory {
 	 */
 	const UPLOAD_HANDLER_SESSION_VAR = 'file_upload_handler_storage';
 	
+	/**
+	 * Contains the valid image extensions w/o svg.
+	 * var string
+	 */
+	const VALID_IMAGE_EXTENSIONS = ['jpeg', 'jpg', 'png', 'gif'];
+	
 	/**
 	 * Contains the registered upload fields. 
 	 * 
@@ -417,4 +424,28 @@ class UploadHandler extends SingletonFactory {
 		
 		WCF::getSession()->register(self::UPLOAD_HANDLER_SESSION_VAR, $storage);
 	}
+	
+	/**
+	 * Returns true, iff the given location contains an image. 
+	 * 
+	 * @param       string          $location
+	 * @param       string          $imageName
+	 * @param       bool            $svgImageAllowed
+	 * @return      bool
+	 */
+	public static function isValidImage($location, $imageName, $svgImageAllowed) {
+		if (!file_exists($location)) {
+			return false;
+		}
+		
+		if (@getimagesize($location) === false && (!$svgImageAllowed || !in_array(FileUtil::getMimeType($location), ['image/svg', 'image/svg+xml']))) {
+			return false; 
+		}
+		
+		if (!in_array(pathinfo($imageName, PATHINFO_EXTENSION), array_merge(self::VALID_IMAGE_EXTENSIONS, $svgImageAllowed ? ['svg'] : []))) {
+			return false;
+		}
+		
+		return true;
+	}
 }