public NTLMv2ClientChallenge(byte[] buffer, int offset)
{
CurrentVersion = ByteReader.ReadByte(buffer, offset + 0);
MaximumSupportedVersion = ByteReader.ReadByte(buffer, offset + 1);
Reserved1 = LittleEndianConverter.ToUInt16(buffer, offset + 2);
Reserved2 = LittleEndianConverter.ToUInt32(buffer, offset + 4);
TimeStamp = FileTimeHelper.ReadFileTime(buffer, offset + 8);
ClientChallenge = ByteReader.ReadBytes(buffer, offset + 16, 8);
Reserved3 = LittleEndianConverter.ToUInt32(buffer, offset + 24);
AVPairs = AVPairUtils.ReadAVPairSequence(buffer, offset + 28);
}
public byte[] GetBytes()
{
byte[] sequenceBytes = AVPairUtils.GetAVPairSequenceBytes(AVPairs);
byte[] buffer = new byte[28 + sequenceBytes.Length];
ByteWriter.WriteByte(buffer, 0, CurrentVersion);
ByteWriter.WriteByte(buffer, 1, MaximumSupportedVersion);
LittleEndianWriter.WriteUInt16(buffer, 2, Reserved1);
LittleEndianWriter.WriteUInt32(buffer, 4, Reserved2);
FileTimeHelper.WriteFileTime(buffer, 8, TimeStamp);
ByteWriter.WriteBytes(buffer, 16, ClientChallenge, 8);
LittleEndianWriter.WriteUInt32(buffer, 24, Reserved3);
ByteWriter.WriteBytes(buffer, 28, sequenceBytes);
return(buffer);
}
public ChallengeMessage(byte[] buffer)
{
Signature = ByteReader.ReadAnsiString(buffer, 0, 8);
MessageType = (MessageTypeName)LittleEndianConverter.ToUInt32(buffer, 8);
TargetName = AuthenticationMessageUtils.ReadUnicodeStringBufferPointer(buffer, 12);
NegotiateFlags = (NegotiateFlags)LittleEndianConverter.ToUInt32(buffer, 20);
ServerChallenge = ByteReader.ReadBytes(buffer, 24, 8);
// Reserved
byte[] targetInfoBytes = AuthenticationMessageUtils.ReadBufferPointer(buffer, 40);
if (targetInfoBytes.Length > 0)
{
TargetInfo = AVPairUtils.ReadAVPairSequence(targetInfoBytes, 0);
}
if ((NegotiateFlags & NegotiateFlags.Version) > 0)
{
Version = new NTLMVersion(buffer, 48);
}
}
public byte[] GetBytes()
{
if ((NegotiateFlags & NegotiateFlags.TargetNameSupplied) == 0)
{
TargetName = String.Empty;
}
byte[] targetInfoBytes = AVPairUtils.GetAVPairSequenceBytes(TargetInfo);
if ((NegotiateFlags & NegotiateFlags.TargetInfo) == 0)
{
targetInfoBytes = new byte[0];
}
int fixedLength = 48;
if ((NegotiateFlags & NegotiateFlags.Version) > 0)
{
fixedLength += 8;
}
int payloadLength = TargetName.Length * 2 + targetInfoBytes.Length;
byte[] buffer = new byte[fixedLength + payloadLength];
ByteWriter.WriteAnsiString(buffer, 0, AuthenticateMessage.ValidSignature, 8);
LittleEndianWriter.WriteUInt32(buffer, 8, (uint)MessageType);
LittleEndianWriter.WriteUInt32(buffer, 20, (uint)NegotiateFlags);
ByteWriter.WriteBytes(buffer, 24, ServerChallenge);
if ((NegotiateFlags & NegotiateFlags.Version) > 0)
{
Version.WriteBytes(buffer, 48);
}
int offset = fixedLength;
AuthenticationMessageUtils.WriteBufferPointer(buffer, 12, (ushort)(TargetName.Length * 2), (uint)offset);
ByteWriter.WriteUTF16String(buffer, ref offset, TargetName);
AuthenticationMessageUtils.WriteBufferPointer(buffer, 40, (ushort)targetInfoBytes.Length, (uint)offset);
ByteWriter.WriteBytes(buffer, ref offset, targetInfoBytes);
return(buffer);
}
public override NTStatus GetChallengeMessage(out object context, NegotiateMessage negotiateMessage, out ChallengeMessage challengeMessage)
{
byte[] serverChallenge = GenerateServerChallenge();
context = new AuthContext(serverChallenge);
challengeMessage = new ChallengeMessage();
// https://msdn.microsoft.com/en-us/library/cc236691.aspx
challengeMessage.NegotiateFlags = NegotiateFlags.TargetTypeServer |
NegotiateFlags.TargetInfo |
NegotiateFlags.TargetNameSupplied |
NegotiateFlags.Version;
// [MS-NLMP] NTLMSSP_NEGOTIATE_NTLM MUST be set in the [..] CHALLENGE_MESSAGE to the client.
challengeMessage.NegotiateFlags |= NegotiateFlags.NTLMSessionSecurity;
if ((negotiateMessage.NegotiateFlags & NegotiateFlags.UnicodeEncoding) > 0)
{
challengeMessage.NegotiateFlags |= NegotiateFlags.UnicodeEncoding;
}
else if ((negotiateMessage.NegotiateFlags & NegotiateFlags.OEMEncoding) > 0)
{
challengeMessage.NegotiateFlags |= NegotiateFlags.OEMEncoding;
}
if ((negotiateMessage.NegotiateFlags & NegotiateFlags.ExtendedSessionSecurity) > 0)
{
challengeMessage.NegotiateFlags |= NegotiateFlags.ExtendedSessionSecurity;
}
else if ((negotiateMessage.NegotiateFlags & NegotiateFlags.LanManagerSessionKey) > 0)
{
challengeMessage.NegotiateFlags |= NegotiateFlags.LanManagerSessionKey;
}
if ((negotiateMessage.NegotiateFlags & NegotiateFlags.Sign) > 0)
{
// [MS-NLMP] If the client sends NTLMSSP_NEGOTIATE_SIGN to the server in the NEGOTIATE_MESSAGE,
// the server MUST return NTLMSSP_NEGOTIATE_SIGN to the client in the CHALLENGE_MESSAGE.
challengeMessage.NegotiateFlags |= NegotiateFlags.Sign;
}
if ((negotiateMessage.NegotiateFlags & NegotiateFlags.Seal) > 0)
{
// [MS-NLMP] If the client sends NTLMSSP_NEGOTIATE_SEAL to the server in the NEGOTIATE_MESSAGE,
// the server MUST return NTLMSSP_NEGOTIATE_SEAL to the client in the CHALLENGE_MESSAGE.
challengeMessage.NegotiateFlags |= NegotiateFlags.Seal;
}
if ((negotiateMessage.NegotiateFlags & NegotiateFlags.Sign) > 0 ||
(negotiateMessage.NegotiateFlags & NegotiateFlags.Seal) > 0)
{
if ((negotiateMessage.NegotiateFlags & NegotiateFlags.Use56BitEncryption) > 0)
{
// [MS-NLMP] If the client sends NTLMSSP_NEGOTIATE_SEAL or NTLMSSP_NEGOTIATE_SIGN with
// NTLMSSP_NEGOTIATE_56 to the server in the NEGOTIATE_MESSAGE, the server MUST return
// NTLMSSP_NEGOTIATE_56 to the client in the CHALLENGE_MESSAGE.
challengeMessage.NegotiateFlags |= NegotiateFlags.Use56BitEncryption;
}
if ((negotiateMessage.NegotiateFlags & NegotiateFlags.Use128BitEncryption) > 0)
{
// [MS-NLMP] If the client sends NTLMSSP_NEGOTIATE_128 to the server in the NEGOTIATE_MESSAGE,
// the server MUST return NTLMSSP_NEGOTIATE_128 to the client in the CHALLENGE_MESSAGE only if
// the client sets NTLMSSP_NEGOTIATE_SEAL or NTLMSSP_NEGOTIATE_SIGN.
challengeMessage.NegotiateFlags |= NegotiateFlags.Use128BitEncryption;
}
}
if ((negotiateMessage.NegotiateFlags & NegotiateFlags.KeyExchange) > 0)
{
challengeMessage.NegotiateFlags |= NegotiateFlags.KeyExchange;
}
challengeMessage.TargetName = Environment.MachineName;
challengeMessage.ServerChallenge = serverChallenge;
challengeMessage.TargetInfo = AVPairUtils.GetAVPairSequence(Environment.MachineName, Environment.MachineName);
challengeMessage.Version = NTLMVersion.Server2003;
return(NTStatus.SEC_I_CONTINUE_NEEDED);
}
