From ca718e343ea3e461e92486a9fb6c27ea816f21e9 Mon Sep 17 00:00:00 2001
From: Tal Aloni <tal.aloni.il@gmail.com>
Date: Sat, 6 Jan 2024 15:09:13 +0200
Subject: [PATCH] GSSAPI: SimpleProtectedNegotiationTokenInit: Add
 GetMechanismTypeListBytes method

---
 .../SimpleProtectedNegotiationTokenInit.cs       | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/SMBLibrary/Authentication/GSSAPI/SPNEGO/SimpleProtectedNegotiationTokenInit.cs b/SMBLibrary/Authentication/GSSAPI/SPNEGO/SimpleProtectedNegotiationTokenInit.cs
index b05b8ef..a553ad6 100644
--- a/SMBLibrary/Authentication/GSSAPI/SPNEGO/SimpleProtectedNegotiationTokenInit.cs
+++ b/SMBLibrary/Authentication/GSSAPI/SPNEGO/SimpleProtectedNegotiationTokenInit.cs
@@ -191,6 +191,11 @@ namespace SMBLibrary.Authentication.GSSAPI
             int constructionLength = 1 + sequenceLengthFieldSize + sequenceLength;
             ByteWriter.WriteByte(buffer, ref offset, MechanismTypeListTag);
             DerEncodingHelper.WriteLength(buffer, ref offset, constructionLength);
+            WriteMechanismTypeListSequence(buffer, ref offset, mechanismTypeList, sequenceLength);
+        }
+
+        protected static void WriteMechanismTypeListSequence(byte[] buffer, ref int offset, List<byte[]> mechanismTypeList, int sequenceLength)
+        {
             ByteWriter.WriteByte(buffer, ref offset, (byte)DerEncodingTag.Sequence);
             DerEncodingHelper.WriteLength(buffer, ref offset, sequenceLength);
             foreach (byte[] mechanismType in mechanismTypeList)
@@ -221,6 +226,17 @@ namespace SMBLibrary.Authentication.GSSAPI
             ByteWriter.WriteBytes(buffer, ref offset, mechanismListMIC);
         }
 
+        public static byte[] GetMechanismTypeListBytes(List<byte[]> mechanismTypeList)
+        {
+            int sequenceLength = GetMechanismTypeListSequenceLength(mechanismTypeList);
+            int sequenceLengthFieldSize = DerEncodingHelper.GetLengthFieldSize(sequenceLength);
+            int constructionLength = 1 + sequenceLengthFieldSize + sequenceLength;
+            byte[] buffer = new byte[constructionLength];
+            int offset = 0;
+            WriteMechanismTypeListSequence(buffer, ref offset, mechanismTypeList, sequenceLength);
+            return buffer;
+        }
+
         private static int GetEncodedMechanismTypeListLength(List<byte[]> mechanismTypeList)
         {
             if (mechanismTypeList == null)