From 5a4a2e1023aee0e1ae02e9d4d6c70d24fcbc8e63 Mon Sep 17 00:00:00 2001
From: James Jackson-South <james_south@hotmail.com>
Date: Wed, 29 Jul 2020 13:52:09 +0100
Subject: [PATCH] Sanitize metadata on jpeg save. Fixes #811

---
 .../Imaging/Formats/JpegFormat.cs             | 19 +++++++++++++++++++
 .../MetaData/ExifPropertyTagConstants.cs      |  5 +++++
 2 files changed, 24 insertions(+)

diff --git a/src/ImageProcessor/Imaging/Formats/JpegFormat.cs b/src/ImageProcessor/Imaging/Formats/JpegFormat.cs
index 882e80fac..ababe8679 100644
--- a/src/ImageProcessor/Imaging/Formats/JpegFormat.cs
+++ b/src/ImageProcessor/Imaging/Formats/JpegFormat.cs
@@ -11,10 +11,12 @@
 namespace ImageProcessor.Imaging.Formats
 {
     using System;
+    using System.Collections.Generic;
     using System.Drawing;
     using System.Drawing.Imaging;
     using System.IO;
     using System.Text;
+    using ImageProcessor.Imaging.MetaData;
 
     /// <summary>
     /// Provides the necessary information to support jpeg images.
@@ -66,6 +68,8 @@ public sealed class JpegFormat : FormatBase
         /// </returns>
         public override Image Save(Stream stream, Image image, long bitDepth)
         {
+            SantizeMetadata(image);
+
             // Jpegs can be saved with different settings to include a quality setting for the JPEG compression.
             // This improves output compression and quality.
             using (EncoderParameters encoderParameters = FormatUtilities.GetEncodingParameters(this.Quality))
@@ -97,6 +101,8 @@ public override Image Save(Stream stream, Image image, long bitDepth)
         /// </returns>
         public override Image Save(string path, Image image, long bitDepth)
         {
+            SantizeMetadata(image);
+
             // Jpegs can be saved with different settings to include a quality setting for the JPEG compression.
             // This improves output compression and quality.
             using (EncoderParameters encoderParameters = FormatUtilities.GetEncodingParameters(this.Quality))
@@ -112,5 +118,18 @@ public override Image Save(string path, Image image, long bitDepth)
 
             return image;
         }
+
+        // System.Drawing's jpeg encoder throws when proprietory tags are included in the metadata
+        // https://github.com/JimBobSquarePants/ImageProcessor/issues/811
+        private static void SantizeMetadata(Image image)
+        {
+            foreach (int id in image.PropertyIdList)
+            {
+                if (Array.IndexOf(ExifPropertyTagConstants.Ids, id) == -1)
+                {
+                    image.RemovePropertyItem(id);
+                }
+            }
+        }
     }
 }
\ No newline at end of file
diff --git a/src/ImageProcessor/Imaging/MetaData/ExifPropertyTagConstants.cs b/src/ImageProcessor/Imaging/MetaData/ExifPropertyTagConstants.cs
index 4b8522e98..e9e67c4f3 100644
--- a/src/ImageProcessor/Imaging/MetaData/ExifPropertyTagConstants.cs
+++ b/src/ImageProcessor/Imaging/MetaData/ExifPropertyTagConstants.cs
@@ -83,5 +83,10 @@ public static class ExifPropertyTagConstants
         /// Gets all known property items
         /// </summary>
         public static readonly ExifPropertyTag[] All = (ExifPropertyTag[])Enum.GetValues(typeof(ExifPropertyTag));
+
+        /// <summary>
+        /// Gets the ids of all valid EXIF property items.
+        /// </summary>
+        public static readonly int[] Ids = Enum.GetValues(typeof(ExifPropertyTag)).Cast<int>().ToArray();
     }
 }