From af50099f225ff6d62a6d1aa5dfa7c29ced625835 Mon Sep 17 00:00:00 2001
From: Tal Aloni <tal.aloni.il@gmail.com>
Date: Sat, 20 May 2017 10:50:37 +0300
Subject: [PATCH] IndependentNTLMAuthenticationProvider: Workaround for NTLMv2
 with LmChallengeResponse length of 0 bytes

---
 .../NTLM/IndependentNTLMAuthenticationProvider.cs    | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/SMBLibrary/Authentication/NTLM/IndependentNTLMAuthenticationProvider.cs b/SMBLibrary/Authentication/NTLM/IndependentNTLMAuthenticationProvider.cs
index 62fd319..877b050 100644
--- a/SMBLibrary/Authentication/NTLM/IndependentNTLMAuthenticationProvider.cs
+++ b/SMBLibrary/Authentication/NTLM/IndependentNTLMAuthenticationProvider.cs
@@ -301,11 +301,15 @@ namespace SMBLibrary.Authentication.NTLM
         /// </summary>
         private bool AuthenticateV2(string domainName, string accountName, string password, byte[] serverChallenge, byte[] lmResponse, byte[] ntResponse)
         {
-            byte[] _LMv2ClientChallenge = ByteReader.ReadBytes(lmResponse, 16, 8);
-            byte[] expectedLMv2Response = NTLMCryptography.ComputeLMv2Response(serverChallenge, _LMv2ClientChallenge, password, accountName, domainName);
-            if (ByteUtils.AreByteArraysEqual(expectedLMv2Response, lmResponse))
+            // Note: Linux CIFS VFS 3.10 will send LmChallengeResponse with length of 0 bytes
+            if (lmResponse.Length == 24)
             {
-                return true;
+                byte[] _LMv2ClientChallenge = ByteReader.ReadBytes(lmResponse, 16, 8);
+                byte[] expectedLMv2Response = NTLMCryptography.ComputeLMv2Response(serverChallenge, _LMv2ClientChallenge, password, accountName, domainName);
+                if (ByteUtils.AreByteArraysEqual(expectedLMv2Response, lmResponse))
+                {
+                    return true;
+                }
             }
 
             if (AuthenticationMessageUtils.IsNTLMv2NTResponse(ntResponse))