public NTStatus AcceptSecurityContext(ref object context, byte[] inputToken, out byte[] outputToken)
{
outputToken = null;
if (!AuthenticationMessageUtils.IsSignatureValid(inputToken))
{
return(NTStatus.SEC_E_INVALID_TOKEN);
}
MessageTypeName messageType = AuthenticationMessageUtils.GetMessageType(inputToken);
if (messageType == MessageTypeName.Negotiate)
{
NegotiateMessage input = new NegotiateMessage(inputToken);
ChallengeMessage output;
NTStatus status = GetChallengeMessage(out context, input, out output);
outputToken = output.GetBytes();
return(status);
}
else if (messageType == MessageTypeName.Authenticate)
{
AuthenticateMessage message = new AuthenticateMessage(inputToken);
return(Authenticate(context, message));
}
else
{
return(NTStatus.SEC_E_INVALID_TOKEN);
}
}
public override NTStatus Authenticate(object context, byte[] authenticateMessageBytes)
{
AuthenticateMessage message;
try
{
message = new AuthenticateMessage(authenticateMessageBytes);
}
catch
{
return(NTStatus.SEC_E_INVALID_TOKEN);
}
if (!(context is AuthContext authContext))
{
// There are two possible reasons for authContext to be null:
// 1. We have a bug in our implementation, let's assume that's not the case,
// according to [MS-SMB2] 3.3.5.5.1 we aren't allowed to return SEC_E_INVALID_HANDLE anyway.
// 2. The client sent AuthenticateMessage without sending NegotiateMessage first,
// in this case the correct response is SEC_E_INVALID_TOKEN.
return(NTStatus.SEC_E_INVALID_TOKEN);
}
authContext.DomainName = message.DomainName;
authContext.UserName = message.UserName;
authContext.WorkStation = message.WorkStation;
if (message.Version != null)
{
authContext.OSVersion = message.Version.ToString();
}
if ((message.NegotiateFlags & NegotiateFlags.Anonymous) > 0)
{
if (!EnableGuestLogin)
{
return(NTStatus.STATUS_LOGON_FAILURE);
}
authContext.IsGuest = true;
return(NTStatus.STATUS_SUCCESS);
}
if (!m_loginCounter.HasRemainingLoginAttempts(message.UserName.ToLower()))
{
return(NTStatus.STATUS_ACCOUNT_LOCKED_OUT);
}
string password = m_GetUserPassword(message.UserName);
if (password == null)
{
if (EnableGuestLogin)
{
authContext.IsGuest = true;
return(NTStatus.STATUS_SUCCESS);
}
if (m_loginCounter.HasRemainingLoginAttempts(message.UserName.ToLower(), true))
{
return(NTStatus.STATUS_LOGON_FAILURE);
}
return(NTStatus.STATUS_ACCOUNT_LOCKED_OUT);
}
bool success;
byte[] serverChallenge = authContext.ServerChallenge;
byte[] sessionBaseKey;
byte[] keyExchangeKey = null;
if ((message.NegotiateFlags & NegotiateFlags.ExtendedSessionSecurity) > 0)
{
if (AuthenticationMessageUtils.IsNTLMv1ExtendedSessionSecurity(message.LmChallengeResponse))
{
// NTLM v1 Extended Session Security:
success = AuthenticateV1Extended(password, serverChallenge, message.LmChallengeResponse, message.NtChallengeResponse);
if (success)
{
// https://msdn.microsoft.com/en-us/library/cc236699.aspx
sessionBaseKey = new MD4().GetByteHashFromBytes(NtlmCryptography.NTOWFv1(password));
byte[] lmowf = NtlmCryptography.LMOWFv1(password);
keyExchangeKey = NtlmCryptography.KXKey(sessionBaseKey, message.NegotiateFlags, message.LmChallengeResponse, serverChallenge, lmowf);
}
}
else
{
// NTLM v2:
success = AuthenticateV2(message.DomainName, message.UserName, password, serverChallenge, message.LmChallengeResponse, message.NtChallengeResponse);
if (success)
{
// https://msdn.microsoft.com/en-us/library/cc236700.aspx
byte[] responseKeyNT = NtlmCryptography.NTOWFv2(password, message.UserName, message.DomainName);
byte[] ntProofStr = ByteReader.ReadBytes(message.NtChallengeResponse, 0, 16);
using HMACMD5 hmacmd5 = new HMACMD5(responseKeyNT);
sessionBaseKey = hmacmd5.ComputeHash(ntProofStr);
keyExchangeKey = sessionBaseKey;
}
}
}
else
{
success = AuthenticateV1(password, serverChallenge, message.LmChallengeResponse, message.NtChallengeResponse);
if (success)
{
// https://msdn.microsoft.com/en-us/library/cc236699.aspx
sessionBaseKey = new MD4().GetByteHashFromBytes(NtlmCryptography.NTOWFv1(password));
byte[] lmowf = NtlmCryptography.LMOWFv1(password);
keyExchangeKey = NtlmCryptography.KXKey(sessionBaseKey, message.NegotiateFlags, message.LmChallengeResponse, serverChallenge, lmowf);
}
}
if (success)
{
// https://msdn.microsoft.com/en-us/library/cc236676.aspx
// https://blogs.msdn.microsoft.com/openspecification/2010/04/19/ntlm-keys-and-sundry-stuff/
if ((message.NegotiateFlags & NegotiateFlags.KeyExchange) > 0)
{
authContext.SessionKey = RC4.Decrypt(keyExchangeKey, message.EncryptedRandomSessionKey);
}
else
{
authContext.SessionKey = keyExchangeKey;
}
return(NTStatus.STATUS_SUCCESS);
}
if (m_loginCounter.HasRemainingLoginAttempts(message.UserName.ToLower(), true))
{
return(NTStatus.STATUS_LOGON_FAILURE);
}
return(NTStatus.STATUS_ACCOUNT_LOCKED_OUT);
}
public abstract NTStatus Authenticate(object context, AuthenticateMessage authenticateMessage);
