private static AuthenticateMessage CreateAuthenticateMessage(string accountNameToAuth, byte[] lmChallengeResponse, byte[] ntChallengeResponse)
{
AuthenticateMessage authenticateMessage = new AuthenticateMessage();
authenticateMessage.NegotiateFlags = NegotiateFlags.UnicodeEncoding |
NegotiateFlags.OEMEncoding |
NegotiateFlags.Sign |
NegotiateFlags.NTLMSessionSecurity |
NegotiateFlags.AlwaysSign |
NegotiateFlags.Version |
NegotiateFlags.Use128BitEncryption |
NegotiateFlags.Use56BitEncryption;
if (AuthenticationMessageUtils.IsNTLMv1ExtendedSessionSecurity(lmChallengeResponse) ||
AuthenticationMessageUtils.IsNTLMv2NTResponse(ntChallengeResponse))
{
authenticateMessage.NegotiateFlags |= NegotiateFlags.ExtendedSessionSecurity;
}
else
{
authenticateMessage.NegotiateFlags |= NegotiateFlags.LanManagerSessionKey;
}
authenticateMessage.UserName = accountNameToAuth;
authenticateMessage.LmChallengeResponse = lmChallengeResponse;
authenticateMessage.NtChallengeResponse = ntChallengeResponse;
authenticateMessage.Version = NTLMVersion.Server2003;
return(authenticateMessage);
}
private static ChallengeMessage GetChallengeMessage(byte[] messageBytes)
{
if (AuthenticationMessageUtils.IsSignatureValid(messageBytes))
{
MessageTypeName messageType = AuthenticationMessageUtils.GetMessageType(messageBytes);
if (messageType == MessageTypeName.Challenge)
{
try
{
return(new ChallengeMessage(messageBytes));
}
catch
{
return(null);
}
}
}
return(null);
}
private static byte[] GetExportedSessionKey(byte[] sessionBaseKey, AuthenticateMessage message, byte[] serverChallenge, byte[] lmowf)
{
byte[] keyExchangeKey;
if (AuthenticationMessageUtils.IsNTLMv2NTResponse(message.NtChallengeResponse))
{
keyExchangeKey = sessionBaseKey;
}
else
{
keyExchangeKey = NtlmCryptography.KXKey(sessionBaseKey, message.NegotiateFlags, message.LmChallengeResponse, serverChallenge, lmowf);
}
if ((message.NegotiateFlags & NegotiateFlags.KeyExchange) > 0)
{
return(RC4.Decrypt(keyExchangeKey, message.EncryptedRandomSessionKey));
}
return(keyExchangeKey);
}
public virtual NTStatus AcceptSecurityContext(ref GssContext?context, byte[] inputToken, out byte[]?outputToken)
{
outputToken = null;
SimpleProtectedNegotiationToken?spnegoToken = null;
try
{
spnegoToken = SimpleProtectedNegotiationToken.ReadToken(inputToken, 0, false);
}
catch
{
// ignored
}
if (spnegoToken != null)
{
if (spnegoToken is SimpleProtectedNegotiationTokenInit tokenInit)
{
if (tokenInit.MechanismTypeList.Count == 0)
{
return(NTStatus.SEC_E_INVALID_TOKEN);
}
// RFC 4178: Note that in order to avoid an extra round trip, the first context establishment token
// of the initiator's preferred mechanism SHOULD be embedded in the initial negotiation message.
byte[] preferredMechanism = tokenInit.MechanismTypeList[0];
IGssMechanism?mechanism = FindMechanism(preferredMechanism);
bool isPreferredMechanism = (mechanism != null);
if (!isPreferredMechanism)
{
mechanism = FindMechanism(tokenInit.MechanismTypeList);
}
if (mechanism == null)
{
return(NTStatus.SEC_E_SECPKG_NOT_FOUND);
}
NTStatus status;
context = new GssContext(mechanism, null);
if (isPreferredMechanism)
{
status = mechanism.AcceptSecurityContext(ref context.MechanismContext, tokenInit.MechanismToken, out byte[] mechanismOutput);
outputToken = GetSpnegoTokenResponseBytes(mechanismOutput, status, mechanism.Identifier);
}
else
{
status = NTStatus.SEC_I_CONTINUE_NEEDED;
outputToken = GetSpnegoTokenResponseBytes(null, status, mechanism.Identifier);
}
return(status);
}
else // SimpleProtectedNegotiationTokenResponse
{
if (context == null)
{
return(NTStatus.SEC_E_INVALID_TOKEN);
}
IGssMechanism mechanism = context.Mechanism;
SimpleProtectedNegotiationTokenResponse tokenResponse = (SimpleProtectedNegotiationTokenResponse)spnegoToken;
NTStatus status = mechanism.AcceptSecurityContext(ref context.MechanismContext, tokenResponse.ResponseToken, out byte[] mechanismOutput);
outputToken = GetSpnegoTokenResponseBytes(mechanismOutput, status, null);
return(status);
}
}
// [MS-SMB] The Windows GSS implementation supports raw Kerberos / NTLM messages in the SecurityBlob.
// [MS-SMB2] Windows [..] will also accept raw Kerberos messages and implicit NTLM messages as part of GSS authentication.
if (!AuthenticationMessageUtils.IsSignatureValid(inputToken))
{
return(NTStatus.SEC_E_INVALID_TOKEN);
}
MessageTypeName messageType = AuthenticationMessageUtils.GetMessageType(inputToken);
IGssMechanism? ntlmAuthenticationProvider = FindMechanism(NtlmSspIdentifier);
if (ntlmAuthenticationProvider == null)
{
return(NTStatus.SEC_E_SECPKG_NOT_FOUND);
}
if (messageType == MessageTypeName.Negotiate)
{
context = new GssContext(ntlmAuthenticationProvider, null);
}
if (context == null)
{
return(NTStatus.SEC_E_INVALID_TOKEN);
}
return(ntlmAuthenticationProvider.AcceptSecurityContext(ref context.MechanismContext, inputToken, out outputToken));
}
public NTStatus AcceptSecurityContext(ref object context, byte[] inputToken, out byte[] outputToken)
{
outputToken = null;
SimpleProtectedNegotiationToken spnegoToken = SimpleProtectedNegotiationToken.ReadToken(inputToken, 0);
if (spnegoToken != null)
{
if (spnegoToken is SimpleProtectedNegotiationTokenInit)
{
SimpleProtectedNegotiationTokenInit tokenInit = (SimpleProtectedNegotiationTokenInit)spnegoToken;
IGSSMechanism mechanism = FindMechanism(tokenInit.MechanismTypeList);
if (mechanism != null)
{
byte[] mechanismOutput;
NTStatus status = mechanism.AcceptSecurityContext(ref context, tokenInit.MechanismToken, out mechanismOutput);
outputToken = GetSPNEGOTokenResponseBytes(mechanismOutput, status, mechanism.Identifier);
m_contextToMechanism[context] = mechanism;
return(status);
}
return(NTStatus.SEC_E_SECPKG_NOT_FOUND);
}
else // SimpleProtectedNegotiationTokenResponse
{
IGSSMechanism mechanism;
if (!m_contextToMechanism.TryGetValue(context, out mechanism))
{
// We assume that the problem is not with our implementation and that the client has sent
// SimpleProtectedNegotiationTokenResponse without first sending SimpleProtectedNegotiationTokenInit.
return(NTStatus.SEC_E_INVALID_TOKEN);
}
SimpleProtectedNegotiationTokenResponse tokenResponse = (SimpleProtectedNegotiationTokenResponse)spnegoToken;
byte[] mechanismOutput;
NTStatus status = mechanism.AcceptSecurityContext(ref context, tokenResponse.ResponseToken, out mechanismOutput);
outputToken = GetSPNEGOTokenResponseBytes(mechanismOutput, status, null);
return(status);
}
}
else
{
// [MS-SMB] The Windows GSS implementation supports raw Kerberos / NTLM messages in the SecurityBlob.
// [MS-SMB2] Windows [..] will also accept raw Kerberos messages and implicit NTLM messages as part of GSS authentication.
if (AuthenticationMessageUtils.IsSignatureValid(inputToken))
{
MessageTypeName messageType = AuthenticationMessageUtils.GetMessageType(inputToken);
IGSSMechanism ntlmAuthenticationProvider = FindMechanism(NTLMSSPIdentifier);
if (ntlmAuthenticationProvider != null)
{
NTStatus status = ntlmAuthenticationProvider.AcceptSecurityContext(ref context, inputToken, out outputToken);
if (messageType == MessageTypeName.Negotiate)
{
m_contextToMechanism[context] = ntlmAuthenticationProvider;
}
return(status);
}
else
{
return(NTStatus.SEC_E_SECPKG_NOT_FOUND);
}
}
}
return(NTStatus.SEC_E_INVALID_TOKEN);
}
