From a2b6908c07d1857839d4bb4a07956220da90b982 Mon Sep 17 00:00:00 2001
From: Michael VanOverbeek <alkalinethunder@gmail.com>
Date: Sun, 31 Oct 2021 13:44:52 -0400
Subject: [PATCH] Move ComputeDigest to HashHelper

---
 ProjectLighthouse/DigestUtils.cs        | 39 -------------------------
 ProjectLighthouse/Helpers/HashHelper.cs | 30 +++++++++++++++++++
 ProjectLighthouse/Startup.cs            |  5 ++--
 3 files changed, 33 insertions(+), 41 deletions(-)
 delete mode 100644 ProjectLighthouse/DigestUtils.cs

diff --git a/ProjectLighthouse/DigestUtils.cs b/ProjectLighthouse/DigestUtils.cs
deleted file mode 100644
index 392054d2..00000000
--- a/ProjectLighthouse/DigestUtils.cs
+++ /dev/null
@@ -1,39 +0,0 @@
-using System;
-using System.IO;
-using System.Security.Cryptography;
-using System.Text;
-using System.Threading.Tasks;
-
-namespace LBPUnion.ProjectLighthouse
-{
-    public static class DigestUtils
-    {
-        public static async Task<string> ComputeDigest(string path, string authCookie, Stream body,
-            string digestKey)
-        {
-            var memoryStream = new MemoryStream();
-
-            var pathBytes = Encoding.UTF8.GetBytes(path);
-            var cookieBytes = string.IsNullOrEmpty(authCookie)
-                ? Array.Empty<byte>()
-                : Encoding.UTF8.GetBytes(authCookie);
-            var keyBytes = Encoding.UTF8.GetBytes(digestKey);
-                
-            await body.CopyToAsync(memoryStream);
-
-            var bodyBytes = memoryStream.ToArray();
-
-            using var sha1 = IncrementalHash.CreateHash(HashAlgorithmName.SHA1);
-            sha1.AppendData(bodyBytes);
-            if (cookieBytes.Length > 0)
-                sha1.AppendData(cookieBytes);
-            sha1.AppendData(pathBytes);
-            sha1.AppendData(keyBytes);
-
-            var digestBytes = sha1.GetHashAndReset();
-            var digestString = Convert.ToHexString(digestBytes).ToLower();
-
-            return digestString;
-        }
-    }
-}
\ No newline at end of file
diff --git a/ProjectLighthouse/Helpers/HashHelper.cs b/ProjectLighthouse/Helpers/HashHelper.cs
index b2ea531e..72c7724a 100644
--- a/ProjectLighthouse/Helpers/HashHelper.cs
+++ b/ProjectLighthouse/Helpers/HashHelper.cs
@@ -1,8 +1,10 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
+using System.IO;
 using System.Security.Cryptography;
 using System.Text;
+using System.Threading.Tasks;
 
 namespace LBPUnion.ProjectLighthouse.Helpers {
     [SuppressMessage("ReSharper", "UnusedMember.Global")]
@@ -45,5 +47,33 @@ namespace LBPUnion.ProjectLighthouse.Helpers {
 
             return BCryptHash(Sha256Hash(bytes));
         }
+        
+        public static async Task<string> ComputeDigest(string path, string authCookie, Stream body,
+            string digestKey)
+        {
+            var memoryStream = new MemoryStream();
+
+            var pathBytes = Encoding.UTF8.GetBytes(path);
+            var cookieBytes = string.IsNullOrEmpty(authCookie)
+                ? Array.Empty<byte>()
+                : Encoding.UTF8.GetBytes(authCookie);
+            var keyBytes = Encoding.UTF8.GetBytes(digestKey);
+                
+            await body.CopyToAsync(memoryStream);
+
+            var bodyBytes = memoryStream.ToArray();
+
+            using var sha1 = IncrementalHash.CreateHash(HashAlgorithmName.SHA1);
+            sha1.AppendData(bodyBytes);
+            if (cookieBytes.Length > 0)
+                sha1.AppendData(cookieBytes);
+            sha1.AppendData(pathBytes);
+            sha1.AppendData(keyBytes);
+
+            var digestBytes = sha1.GetHashAndReset();
+            var digestString = Convert.ToHexString(digestBytes).ToLower();
+
+            return digestString;
+        }
     }
 }
\ No newline at end of file
diff --git a/ProjectLighthouse/Startup.cs b/ProjectLighthouse/Startup.cs
index d3210b67..9ab07443 100644
--- a/ProjectLighthouse/Startup.cs
+++ b/ProjectLighthouse/Startup.cs
@@ -5,6 +5,7 @@ using System.Reflection.Metadata.Ecma335;
 using System.Runtime.InteropServices.ComTypes;
 using System.Threading.Tasks;
 using Kettu;
+using LBPUnion.ProjectLighthouse.Helpers;
 using LBPUnion.ProjectLighthouse.Logging;
 using LBPUnion.ProjectLighthouse.Serialization;
 using Microsoft.AspNetCore.Builder;
@@ -75,7 +76,7 @@ namespace LBPUnion.ProjectLighthouse
                 var digestPath = context.Request.Path;
                 var body = context.Request.Body;
 
-                var clientRequestDigest = await DigestUtils.ComputeDigest(digestPath, authCookie, body, serverDigestKey);
+                var clientRequestDigest = await HashHelper.ComputeDigest(digestPath, authCookie, body, serverDigestKey);
 
                 // Check the digest we've just calculated against the X-Digest-A header if the game set the header. They should match.
                 if (context.Request.Headers.TryGetValue("X-Digest-A", out var sentDigest))
@@ -104,7 +105,7 @@ namespace LBPUnion.ProjectLighthouse
                     responseBuffer.Position = 0;
                     
                     // Compute the digest for the response.
-                    var serverDigest = await DigestUtils.ComputeDigest(context.Request.Path, authCookie,
+                    var serverDigest = await HashHelper.ComputeDigest(context.Request.Path, authCookie,
                         responseBuffer, serverDigestKey);
                     context.Response.Headers.Add("X-Digest-A", serverDigest);
                 }