Fix out-of-bounds safety in BlobToFileNameResolver

Co-authored-by: Renish Patel <renishpatel2482001@gmail.com>

Author: Ronitsabhaya75

src/Storage/Storage/Common/BlobToFileNameResolver.cs

@@ -1,4 +1,4 @@
-// ----------------------------------------------------------------------------------
+// ----------------------------------------------------------------------------------
 //
 // Copyright Microsoft Corporation
 // Licensed under the Apache License, Version 2.0 (the "License");
@@ -281,8 +281,11 @@ private static bool IsReservedFileName(string fileName)
 
         private string ResolveFileNameConflict(string baseFileName)
         {
-            // TODO - MaxFileNameLength could be <= 0.
             int maxFileNameLength = this.getMaxFileNameLength();
+            if (maxFileNameLength <= 0)
+            {
+                throw new ArgumentOutOfRangeException(nameof(maxFileNameLength), "Max file name length must be greater than zero.");
+            }
 
             Func<string, bool> conflict = delegate (string fileName)
             {
@@ -295,12 +298,16 @@ private string ResolveFileNameConflict(string baseFileName)
             {
                 string postfixString = string.Format(" ({0})", count);
 
-                // TODO - trimLength could be be larger than pathAndFilename.Length, what do we do in this case?
                 int trimLength = (fileName.Length + postfixString.Length + extension.Length) - maxFileNameLength;
 
                 if (trimLength > 0)
                 {
-                    fileName = fileName.Remove(fileName.Length - trimLength);
+                    int startIndex = fileName.Length - trimLength;
+                    if (startIndex < 0)
+                    {
+                        startIndex = 0;
+                    }
+                    fileName = fileName.Remove(startIndex);
                 }
 
                 return string.Format("{0}{1}{2}", fileName, postfixString, extension);