Fix the handling of EXIF data

Author: dtdesign

ts/WoltLabSuite/Core/Api/Files/Upload.ts

@@ -19,7 +19,10 @@ export async function upload(
 
   let exifData: string | null = null;
   if (exifBytes !== null) {
-    exifData = new TextDecoder().decode(exifBytes);
+    exifData = "";
+    for (let i = 0, length = exifBytes.length; i < length; i++) {
+      exifData += exifBytes[i].toString(16).padStart(2, "0");
+    }
   }
 
   const payload = {

ts/WoltLabSuite/Core/Component/File/Upload.ts

@@ -302,7 +302,12 @@ function reportError(element: WoltlabCoreFileUploadElement, file: File | null, m
 async function getExifBytes(file: File): Promise<Exif | null> {
   if (file.type === "image/jpeg") {
     try {
-      return await getExifBytesFromJpeg(file);
+      const bytes = await getExifBytesFromJpeg(file);
+
+      // ExifUtil returns the entire section but we only need the app data.
+      // Removing the first 10 bytes drops the 0xFF 0xE1 marker followed by two
+      // bytes for the length and then 6 bytes for the "Exif\x00\x00" header.
+      return bytes.slice(10);
     } catch {
       return null;
     }

wcfsetup/install/files/js/WoltLabSuite/Core/Api/Files/Upload.js

@@ -150,6 +150,14 @@ public static function createFromExistingFile(
         if ($exifData === null) {
             $exifData = ExifUtil::getExifData($pathname);
 
+            // Remove the `FILE` and `COMPUTED` section because those contain
+            // garbled data anyway and we do not need them in the first place.
+            unset($exifData['FILE'], $exifData['COMPUTED']);
+
+            // We can also discard the `THUMBNAIL` section because it is a
+            // pointless feature and we’re not extracting it either.
+            unset($exifData['THUMBNAIL']);
+
             if ($exifData === []) {
                 $exifData = null;
             }

wcfsetup/install/files/js/WoltLabSuite/Core/Component/File/Upload.js

@@ -76,7 +76,12 @@ private function createTemporaryFile(PostUploadParameters $parameters, int $numb
         $identifier = \bin2hex(\random_bytes(20));
         $objectType = FileProcessor::getInstance()->getObjectType($parameters->objectType);
 
-        $exifData = $this->parseExifData($parameters->exifData);
+        $exifBytes = null;
+        if ($parameters->exifData !== null) {
+            $exifBytes = \hex2bin($parameters->exifData);
+        }
+
+        $exifData = $this->parseExifData($exifBytes);
         if ($exifData !== null) {
             $exifData = JSON::encode($exifData);
         }
@@ -104,7 +109,24 @@ private function parseExifData(?string $exifData): array|null
             return null;
         }
 
-        return Exif::forBytes(0, $exifData)->getParsedExif();
+        $data = Exif::forBytes(0, $exifData)->getParsedExif();
+        if ($data === null) {
+            return null;
+        }
+
+        // Remove the `FILE` and `COMPUTED` section because those contain
+        // garbled data anyway and we do not need them in the first place.
+        unset($data['FILE'], $data['COMPUTED']);
+
+        // We can also discard the `THUMBNAIL` section because it is a
+        // pointless feature and we’re not extracting it either.
+        unset($data['THUMBNAIL']);
+
+        if ($data === []) {
+            return null;
+        }
+
+        return $data;
     }
 }
 

wcfsetup/install/files/lib/data/file/FileEditor.class.php

@@ -294,7 +294,7 @@
 	min-width: 500px;
 	overflow: hidden;
 	padding: 0;
-	position: relative;
+	position: fixed;
 }
 
 .dialog:not([open]) {