/// <summary>
/// Create KRB_ERROR response
/// </summary>
/// <param name="kileConnection">Maintain a connection with a target client. This argument cannot be null.</param>
/// <param name="errorCode">Error code returned by Kerberos or the server when a request fails</param>
/// <param name="errorText">Additional text to help explain the error code. This argument could be null.</param>
/// <param name="errorData">Additional data about the error. This argument could be null.</param>
/// <returns>The created Krb Error response</returns>
/// <exception cref="System.ArgumentNullException">Thrown when the input parameter is null.</exception>
public KileKrbError CreateKrbErrorResponse(
KileConnection kileConnection,
KRB_ERROR_CODE errorCode,
string errorText,
byte[] errorData)
{
KileServerContext serverContext = GetServerContextByKileConnection(kileConnection);
KileKrbError response = new KileKrbError(serverContext);
// Set KRB_ERROR
response.KerberosError.pvno = new Asn1Integer(ConstValue.KERBEROSV5);
response.KerberosError.msg_type = new Asn1Integer((int)MsgType.KRB_ERROR);
response.KerberosError.stime = KileUtility.CurrentKerberosTime;
response.KerberosError.susec = new Microseconds(0);
response.KerberosError.sname = serverContext.SName;
response.KerberosError.realm = new Realm(domain);
response.KerberosError.error_code = new Int32((int)errorCode);
if (errorText != null)
{
response.KerberosError.e_text = new KerberosString(errorText);
}
if (errorData != null)
{
response.KerberosError.e_data = new Asn1OctetString(errorData);
}
return(response);
}
/// <summary>
/// Decode the KRB_ERROR token got from application.
/// </summary>
/// <param name="errorToken">The token got from an application message. This argument cannot be null.</param>
/// <returns>The decoded AP response.</returns>
/// <exception cref="System.ArgumentNullException">Thrown when the input parameter is null.</exception>
/// <exception cref="System.FormatException">Thrown when the errorToken is not valid.</exception>
public KileKrbError ParseKrbError(byte[] errorToken)
{
if (errorToken == null)
{
throw new ArgumentNullException("errorToken");
}
byte[] errorBody = KileUtility.VerifyGssApiTokenHeader(errorToken);
// Check if it has a two-byte tok_id
if (errorBody == null || errorBody.Length <= sizeof(TOK_ID))
{
throw new FormatException("Not a valid KRB_ERROR token!");
}
TOK_ID id = (TOK_ID)KileUtility.ConvertEndian(BitConverter.ToUInt16(errorBody, 0));
if (id != TOK_ID.KRB_ERROR)
{
throw new FormatException("Not a valid KRB_ERROR token!");
}
errorBody = ArrayUtility.SubArray(errorBody, sizeof(TOK_ID));
KileKrbError error = new KileKrbError();
error.FromBytes(errorBody);
return(error);
}
/// <summary>
/// Create KRB_ERROR response
/// </summary>
/// <param name="kileConnection">Maintain a connection with a target client. This argument cannot be null.</param>
/// <param name="errorCode">Error code returned by Kerberos or the server when a request fails</param>
/// <param name="errorText">Additional text to help explain the error code. This argument could be null.</param>
/// <param name="errorData">Additional data about the error. This argument could be null.</param>
/// <returns>The created Krb Error response</returns>
/// <exception cref="System.ArgumentNullException">Thrown when the input parameter is null.</exception>
public KileKrbError CreateKrbErrorResponse(
KileConnection kileConnection,
KRB_ERROR_CODE errorCode,
string errorText,
byte[] errorData)
{
KileServerContext serverContext = GetServerContextByKileConnection(kileConnection);
KileKrbError response = new KileKrbError(serverContext);
// Set KRB_ERROR
response.KerberosError.pvno = new Asn1Integer(ConstValue.KERBEROSV5);
response.KerberosError.msg_type = new Asn1Integer((int)MsgType.KRB_ERROR);
response.KerberosError.stime = KileUtility.CurrentKerberosTime;
response.KerberosError.susec = new Microseconds(0);
response.KerberosError.sname = serverContext.SName;
response.KerberosError.realm = new Realm(domain);
response.KerberosError.error_code = new Int32((int)errorCode);
if (errorText != null)
{
response.KerberosError.e_text = new KerberosString(errorText);
}
if (errorData != null)
{
response.KerberosError.e_data = new Asn1OctetString(errorData);
}
return response;
}
/// <summary>
/// Initialize the context from a token.
/// </summary>
/// <param name="inToken">The token used to initialize.</param>
/// <exception cref="System.NotSupportedException">Thrown when the ContextAttribute contains a flag that not be
/// supported.</exception>
/// <exception cref="System.InvalidOperationException">Thrown when an error is returned.</exception>
public override void Initialize(byte[] inToken)
{
if (inToken == null || inToken.Length == 0)
{
KilePdu response = null;
string sname = ConstValue.KERBEROS_SNAME;
KileAsRequest asRequest;
EncryptionKey subkey = null;
// Create and send AS request for pre-authentication
KdcOptions options = KdcOptions.FORWARDABLE | KdcOptions.RENEWABLE
| KdcOptions.CANONICALIZE | KdcOptions.RENEWABLEOK;
KDCOptions flags = new KDCOptions(KerberosUtility.ConvertInt2Flags((int)options));
// Create and send AS request for pre-authentication
asRequest = client.CreateAsRequest(sname, flags, null, this.GetClientSupportedEtype());
client.SendPdu(asRequest);
response = client.ExpectPdu(ConstValue.TIMEOUT_DEFAULT);
KileKrbError preAuthError = response as KileKrbError;
if ((preAuthError == null) || (!preAuthError.ErrorCode.Equals(KRB_ERROR_CODE.KDC_ERR_PREAUTH_REQUIRED)))
{
throw new InvalidOperationException("The Error code should be KDC_ERR_PREAUTH_REQUIRED");
}
// Create and send AS request for TGT
var defualtEncryptType = (client.ClientContext.TgsSessionKey == null) ? EncryptionType.RC4_HMAC : (EncryptionType)client.ClientContext.TgsSessionKey.keytype.Value;
PaEncTimeStamp timestamp = client.ConstructPaEncTimeStamp(defualtEncryptType);
PaPacRequest pacRequest = client.ConstructPaPacRequest(true);
Asn1SequenceOf <PA_DATA> paData = client.ConstructPaData(timestamp, pacRequest);
if ((contextAttribute & ClientSecurityContextAttribute.DceStyle) == ClientSecurityContextAttribute.DceStyle)
{
asRequest = client.CreateAsRequest(sname, flags, paData, this.GetClientSupportedEtype());
//subkey = new EncryptionKey((int)EncryptionType.AES256_CTS_HMAC_SHA1_96,
// KileUtility.GenerateRandomBytes(ConstValue.AES_KEY_LENGTH));
var key = KeyGenerator.MakeKey(EncryptionType.AES256_CTS_HMAC_SHA1_96, client.ClientContext.Password, client.ClientContext.Salt);
subkey = new EncryptionKey(new KerbInt32((long)EncryptionType.AES256_CTS_HMAC_SHA1_96), new Asn1OctetString(key));
}
else
{
asRequest = client.CreateAsRequest(sname, flags, paData, this.GetClientSupportedEtype());
}
client.SendPdu(asRequest);
response = client.ExpectPdu(ConstValue.TIMEOUT_DEFAULT);
if (response.GetType() == typeof(KileKrbError))
{
throw new InvalidOperationException("Received Kerberos Error response: " + ((KileKrbError)response).ErrorCode);
}
KileAsResponse asResponse = (KileAsResponse)response;
// Create and send TGS request
// for example: "KERB.COMldapsut02.kerb.com"
client.ClientContext.Salt = domain.ToUpper();
string[] nameList = userLogonName.Split('/');
foreach (string name in nameList)
{
client.ClientContext.Salt += name;
}
KileTgsRequest tgsRequest = client.CreateTgsRequest(this.serverName,
flags,
null,
ChecksumType.hmac_md5_string,
null,
null);
client.SendPdu(tgsRequest);
response = client.ExpectPdu(ConstValue.TIMEOUT_DEFAULT);
if (response.GetType() == typeof(KileKrbError))
{
throw new InvalidOperationException("Received Kerberos Error response: " + ((KileKrbError)response).ErrorCode);
}
KileTgsResponse tgsResponse = (KileTgsResponse)response;
ApOptions apOption;
ChecksumFlags checksumFlag;
GetFlagsByContextAttribute(out apOption, out checksumFlag);
KerbAuthDataTokenRestrictions adRestriction =
client.ConstructKerbAuthDataTokenRestrictions(0,
(uint)LSAP_TOKEN_INFO_INTEGRITY_Flags.FULL_TOKEN,
(uint)LSAP_TOKEN_INFO_INTEGRITY_TokenIL.Medium,
new Guid().ToString());
AdAuthDataApOptions adApOptions = client.ConstructAdAuthDataApOptions(ConstValue.KERB_AP_OPTIONS_CBT);
AuthorizationData authData = client.ConstructAuthorizationData(adRestriction, adApOptions);
KileApRequest apRequest = client.CreateApRequest(apOption,
ChecksumType.ap_authenticator_8003,
ConstValue.SEQUENCE_NUMBER_DEFAULT,
checksumFlag,
subkey,
authData);
token = apRequest.ToBytes();
bool isMutualAuth = (contextAttribute & ClientSecurityContextAttribute.MutualAuth)
== ClientSecurityContextAttribute.MutualAuth;
bool isDceStyle = (contextAttribute & ClientSecurityContextAttribute.DceStyle)
== ClientSecurityContextAttribute.DceStyle;
if (isMutualAuth || isDceStyle)
{
continueProcess = true; // SEC_I_CONTINUE_NEEDED;
}
else
{
continueProcess = false; // SEC_E_OK;
}
}
else // mutual authentication
{
KileApResponse apResponse = client.ParseApResponse(inToken);
token = null;
if ((contextAttribute & ClientSecurityContextAttribute.DceStyle)
== ClientSecurityContextAttribute.DceStyle)
{
KileApResponse apResponseSend = client.CreateApResponse(null);
token = apResponseSend.ToBytes();
}
this.continueProcess = false; // SEC_E_OK;
}
}
/// <summary>
/// Decode KILE PDUs from received message bytes
/// </summary>
/// <param name="endPoint">An endpoint from which the message bytes are received</param>
/// <param name="receivedBytes">The received bytes to be decoded</param>
/// <param name="consumedLength">Length of message bytes consumed by decoder</param>
/// <param name="expectedLength">Length of message bytes the decoder expects to receive</param>
/// <returns>The decoded KILE PDUs</returns>
/// <exception cref="System.FormatException">thrown when a kile message type is unsupported</exception>
internal KilePdu[] DecodePacketCallback(object endPoint,
byte[] receivedBytes,
out int consumedLength,
out int expectedLength)
{
// initialize lengths
consumedLength = 0;
expectedLength = 0;
if (null == receivedBytes || 0 == receivedBytes.Length)
{
return(null);
}
if (!isClientRole)
{
serverContext = null;
if (serverContextList != null)
{
KileConnection kileConnection = new KileConnection((IPEndPoint)endPoint);
if (!serverContextList.ContainsKey(kileConnection))
{
serverContext = new KileServerContext();
serverContext.TransportType = connectionType;
serverContextList.Add(kileConnection, serverContext);
}
else
{
serverContext = serverContextList[kileConnection];
}
}
if (serverContext == null)
{
throw new InvalidOperationException("The kileConnection related context does not exist.");
}
}
// TCP has a 4 bytes length header, while UDP has not
byte[] pduBytes = receivedBytes;
if ((isClientRole && clientContext.TransportType == KileConnectionType.TCP) ||
(!isClientRole && serverContext.TransportType == KileConnectionType.TCP))
{
// insufficient data, needs to receive more
if (receivedBytes.Length < sizeof(int))
{
return(null);
}
// get pdu data length
byte[] lengthBytes = ArrayUtility.SubArray(receivedBytes, 0, sizeof(int));
Array.Reverse(lengthBytes);
int pduLength = BitConverter.ToInt32(lengthBytes, 0);
// insufficient data, needs to receive more
expectedLength = sizeof(int) + pduLength;
if (receivedBytes.Length < expectedLength)
{
return(null);
}
// check if it is a krb zero message
if (pduLength == 0 && receivedBytes.Length == sizeof(int))
{
consumedLength = sizeof(int);
KrbZero krbZeroPdu = new KrbZero(clientContext);
return(new KilePdu[] { krbZeroPdu });
}
// remove length header from pdu bytes
pduBytes = ArrayUtility.SubArray <byte>(receivedBytes, sizeof(int), pduLength);
}
else
{
// UDP has no length header
expectedLength = pduBytes.Length;
}
// get message type
// (the lower 5 bits indicates its kile message type)
MsgType kileMessageType = (MsgType)(pduBytes[0] & 0x1f);
// decode according to message type
consumedLength = expectedLength;
KilePdu pdu = null;
switch (kileMessageType)
{
case MsgType.KRB_AS_REQ:
pdu = new KileAsRequest(serverContext);
break;
case MsgType.KRB_AS_RESP:
pdu = new KileAsResponse(clientContext);
break;
case MsgType.KRB_TGS_REQ:
pdu = new KileTgsRequest(serverContext);
break;
case MsgType.KRB_TGS_RESP:
pdu = new KileTgsResponse(clientContext);
break;
case MsgType.KRB_ERROR:
pdu = new KileKrbError();
break;
default:
throw new FormatException(
"Unsupported Message Type: " + kileMessageType.ToString());
}
pdu.FromBytes(pduBytes);
// update context
if (isClientRole)
{
clientContext.UpdateContext(pdu);
}
else
{
serverContext.UpdateContext(pdu);
}
return(new KilePdu[] { pdu });
}
