From c02c8fe5a96ad535771074f054fe2c1ffcd99d9b Mon Sep 17 00:00:00 2001
From: Johannes Bildstein <johannes@bildstein.at>
Date: Thu, 23 Mar 2017 17:38:54 +0100
Subject: [PATCH] don't allow reading negative length strings

---
 .../MetaData/Profiles/ICC/IccDataReader.cs          | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/ImageSharp/MetaData/Profiles/ICC/IccDataReader.cs b/src/ImageSharp/MetaData/Profiles/ICC/IccDataReader.cs
index fcc5ff705..8076c11a3 100644
--- a/src/ImageSharp/MetaData/Profiles/ICC/IccDataReader.cs
+++ b/src/ImageSharp/MetaData/Profiles/ICC/IccDataReader.cs
@@ -131,6 +131,12 @@ namespace ImageSharp
         /// <returns>The value as a string</returns>
         public string ReadAsciiString(int length)
         {
+            if (length == 0)
+            {
+                return string.Empty;
+            }
+
+            Guard.MustBeGreaterThan(length, 0, nameof(length));
             string value = AsciiEncoding.GetString(this.data, this.AddIndex(length), length);
 
             // remove data after (potential) null terminator
@@ -150,6 +156,13 @@ namespace ImageSharp
         /// <returns>The value as a string</returns>
         public string ReadUnicodeString(int length)
         {
+            if (length == 0)
+            {
+                return string.Empty;
+            }
+
+            Guard.MustBeGreaterThan(length, 0, nameof(length));
+
             return Encoding.BigEndianUnicode.GetString(this.data, this.AddIndex(length), length);
         }