/// <summary>
/// Creates the NTLM negotiate (Type 1) message.
/// </summary>
protected override void BuildMessage()
{
int initialLength = SignatureLength + MessageTypeLength + FlagsLength + SecurityBufferLength * 2 + VersionLength;
int domainBytesLength = 0;
if (domainBytes != null)
{
domainBytesLength = domainBytes.Length;
}
int hostBytesLength = 0;
if (hostBytes != null)
{
hostBytesLength = hostBytes.Length;
}
// Now, build the message. Calculate its length first, including
// signature or type.
int finalLength = initialLength + hostBytesLength + domainBytesLength;
// Set up the response. This will initialize the signature, message
// type, and flags.
InitializeMessage(finalLength, NtlmMessageType.Negotiate);
// Flags. These are the complete set of flags we support.
AddUInt((uint)flags);
// Domain length (two times).
AddUShort(domainBytesLength);
AddUShort(domainBytesLength);
// Domain offset.
AddUInt(Convert.ToUInt32(hostBytesLength + initialLength));
// Host length (two times).
AddUShort(hostBytesLength);
AddUShort(hostBytesLength);
// Host offset (always 32 + 8).
AddUInt(Convert.ToUInt32(initialLength));
// Add version (for debugging purposes)
NtlmVersion version = new NtlmVersion(5, 1, 2600);
AddBytes(version.AsBytes());
// Host (workstation) String.
if (hostBytes != null)
{
AddBytes(hostBytes);
}
// Domain String.
if (domainBytes != null)
{
AddBytes(domainBytes);
}
}
/// <summary>
/// Creates the NTLM authenticate (Type 3) message.
/// </summary>
protected override void BuildMessage()
{
int ntlmResponseLength = ntlmResponse.Length;
int lmResponseLength = lmResponse.Length;
int domainLength = domainBytes != null ? domainBytes.Length : 0;
int hostLength = hostBytes != null ? hostBytes.Length : 0;
int userLength = userBytes.Length;
int sessionKeyLength;
if (sessionKey != null)
{
sessionKeyLength = sessionKey.Length;
}
else
{
sessionKeyLength = 0;
}
// Calculate the layout within the packet
int lmResponseOffset = 72;
if (isMessageIntegrityCodeRequired)
{
lmResponseOffset += 16;
}
int ntlmResponseOffset = lmResponseOffset + lmResponseLength;
int domainOffset = ntlmResponseOffset + ntlmResponseLength;
int userOffset = domainOffset + domainLength;
int hostOffset = userOffset + userLength;
int sessionKeyOffset = hostOffset + hostLength;
int finalLength = sessionKeyOffset + sessionKeyLength;
// Start the response. Length includes signature and type
InitializeMessage(finalLength, NtlmMessageType.Authenticate);
// LM Resp Length (twice)
AddUShort(lmResponseLength);
AddUShort(lmResponseLength);
// LM Resp Offset
AddUInt(Convert.ToUInt32(lmResponseOffset));
// NT Resp Length (twice)
AddUShort(ntlmResponseLength);
AddUShort(ntlmResponseLength);
// NT Resp Offset
AddUInt(Convert.ToUInt32(ntlmResponseOffset));
// Domain length (twice)
AddUShort(domainLength);
AddUShort(domainLength);
// Domain offset.
AddUInt(Convert.ToUInt32(domainOffset));
// User Length (twice)
AddUShort(userLength);
AddUShort(userLength);
// User offset
AddUInt(Convert.ToUInt32(userOffset));
// Host length (twice)
AddUShort(hostLength);
AddUShort(hostLength);
// Host offset
AddUInt(Convert.ToUInt32(hostOffset));
// Session key length (twice)
AddUShort(sessionKeyLength);
AddUShort(sessionKeyLength);
// Session key offset
AddUInt(Convert.ToUInt32(sessionKeyOffset));
// Flags.
AddUInt((uint)negotiatedOptionFlags);
// OS version values (only used for debugging purposes,
// so we are hard-coding 5.1.2600, or Windows XP). A
// future version should likely query the actual OS.
NtlmVersion version = new NtlmVersion(5, 1, 2600);
AddBytes(version.AsBytes());
int micPosition = -1;
if (isMessageIntegrityCodeRequired)
{
micPosition = CurrentOutputPosition;
CurrentOutputPosition += 16;
}
// Add the actual data
AddBytes(lmResponse);
AddBytes(ntlmResponse);
AddBytes(domainBytes);
AddBytes(userBytes);
AddBytes(hostBytes);
if (sessionKey != null)
{
AddBytes(sessionKey);
}
// Write the mic back into its slot in the message
if (isMessageIntegrityCodeRequired)
{
// Computation of message integrity code (MIC) as specified
// in [MS-NLMP] section 3.2.5.1.2.
List <byte> data = new List <byte>();
data.AddRange(type1Message);
data.AddRange(type2Message);
data.AddRange(MessageContents);
byte[] mic;
using (HMACMD5 hmac = new HMACMD5(exportedSessionKey))
{
mic = hmac.ComputeHash(data.ToArray());
}
Array.Copy(mic, 0, MessageContents, micPosition, mic.Length);
}
}
