/// <summary>
/// Checks whether the CMAC is valid and correct or not
/// </summary>
/// <param name="m3Received">Message 3 from client</param>
/// <param name="m3GaStr">Message 3 ECC Ga String</param>
/// <param name="sigmaSequenceCheck">Service Provider Sequence (State) Check</param>
/// <returns>Boolean whether the CMAC was correct</returns>
private bool CheckCmac(M3RequestMessage m3Received, String m3GaStr)
{
log.Debug("CheckCmac(.) started.");
if (m3Received == null || m3GaStr == null)
{
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.InternalServerError);
options.LogThrownException(e);
throw e;
}
// The received CMAC should match a computed CMAC
string m3PsSecPropStr = bMessage.BaToBlobStr(m3Received.reqM3Body.secProperty);
string m3QuoteStr = bMessage.BaToBlobStr(m3Received.reqM3Body.quote);
string m3CmacBlobStr = m3GaStr + m3PsSecPropStr + m3QuoteStr;
byte[] m3CmacBlobBa = bMessage.BlobStrToBa(m3CmacBlobStr);
// Calculate the m3 CMAC value
byte[] m3CmacSmk = cmacAES.Value(sigmaSequenceCheck.currentSmk, m3CmacBlobBa);
string calcM3CmacSmkStr = bMessage.BaToBlobStr(m3CmacSmk);
string m3aesCmacStr = bMessage.BaToBlobStr(m3Received.reqM3Body.aesCmac);
bool cmacCorrect = String.Equals(m3aesCmacStr, calcM3CmacSmkStr, StringComparison.Ordinal);
if (!cmacCorrect)
{
log.Debug("!!! CMAC Check Failure !!!");
}
log.DebugFormat("CheckCmac(.) returning {0}.", cmacCorrect);
return(cmacCorrect);
}
//Build an M3 request
public void buildM3Request(out M3RequestMessage m3Req)
{
string request = Constants.Request;
var m3Msg = new M3RequestMessage(request);
var m3Body = new ReqMsg3Body();
m3Body.aesCmac = Constants.sampleCmacsmk;
m3Body.gaX = Constants.sampleGaXba;
m3Body.gaY = Constants.sampleGaYba;
m3Body.secProperty = Constants.sampleM3secProp;
m3Body.quote = Constants.sampleQuote;
//load a complete message object
m3Msg.reqM3Body = m3Body;
m3Req = m3Msg;
return;
}
/// <summary>
/// Checks whether the received Message is the correct length or not
/// Compare the reported length against the actual length (base16 string length/2)
/// </summary>
/// <param name="m3Received">Message 3 from client</param>
/// <param name="m3ReceivedString">Message 3 as a string</param>
/// <returns>Boolean of whether message length is correct</returns>
private bool CheckMessageLength(M3RequestMessage m3Received, String m3ReceivedString)
{
log.Debug("CheckMessageLength(.) started.");
if (m3Received == null || m3ReceivedString == null)
{
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.InternalServerError);
options.LogThrownException(e);
throw e;
}
bool correctLength = BitConverter.ToUInt32(m3Received.reqHeader.msgLength, 0) == (m3ReceivedString.Length / 2);
if (!correctLength)
{
log.Debug("!!! Length Check Error !!!");
}
log.DebugFormat("CheckMessageLength(.) returning {0}.", correctLength);
return(correctLength);
}
/// <summary>
/// Process Message 3 and Build Message 4
/// </summary>
/// <param name="Request">Message 3 Client Response</param>
/// <param name="sigmaSequenceCheck">Service Provider Sequence (State) Check</param>
/// <returns>Message 4 Repsonse to Client</returns>
public async Task <M4ResponseMessage> ProcessMessage3(HttpRequestMessage Request, SpSequenceCheck sigmaSequenceChk)
{
log.Debug("ProcessMessage3(.) started.");
if (Request == null || sigmaSequenceChk == null)
{
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.PreconditionFailed);
options.LogThrownException(e);
throw e;
}
sigmaSequenceCheck = sigmaSequenceChk;
// Update Client state
if (!sigmaSequenceCheck.UpdateState(Constants.SequenceState.Msg3))
{
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.PreconditionFailed);
options.LogThrownException(e);
throw e;
}
var result = Request.Content.ReadAsStringAsync();
string jsonMsg3Request = result.Result;
M3RequestMessage m3Received = new M3RequestMessage();
try
{
// Attempt to parse request in message 3
m3Received = JsonConvert.DeserializeObject <M3RequestMessage>(jsonMsg3Request);
}
catch (Exception msg3ReqError)
{
log.DebugFormat("******* Message 3 JSON Content Error: {0}", msg3ReqError);
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.InternalServerError);
options.LogThrownException(e);
throw e;
}
if (m3Received == null)
{
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.PreconditionFailed);
options.LogThrownException(e);
throw e;
}
// Check the nonce and the base16 encoded length of the inbound request
string m3ReceivedString = m3Received.GetMsgString();
log.Info("******* Received M3 Request");
log.DebugFormat("{0}{1}", Request.Headers, jsonMsg3Request);
log.DebugFormat("M3 Base16 Encoded String: {0}", m3ReceivedString);
// If failed a check, throw an error
// Getting to this point means there was a problem with the M3 content (including possible quote check failure).
// Reset the state machine and return "Forbidden"
// Check whether to use Nonce or not, and is valid
bool nonceCheck = sigmaSequenceCheck.currentNonce.SequenceEqual(m3Received.reqHeader.nonce);
if (!nonceCheck)
{
log.Debug("Invalid Message 3 Nonce");
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.Forbidden);
options.LogThrownException(e);
throw e;
}
// Check the message has the correct length
bool lengthCheck = CheckMessageLength(m3Received, m3ReceivedString);
if (!lengthCheck)
{
log.Debug("Invalid Message 3 Length");
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.Forbidden);
options.LogThrownException(e);
throw e;
}
// Check the M3 components & Ga
byte[] m3Ga = new byte[m3Received.reqM3Body.gaX.Length + m3Received.reqM3Body.gaY.Length];
System.Buffer.BlockCopy(m3Received.reqM3Body.gaX, 0, m3Ga, 0, m3Received.reqM3Body.gaX.Length);
System.Buffer.BlockCopy(m3Received.reqM3Body.gaY, 0, m3Ga, m3Received.reqM3Body.gaX.Length, m3Received.reqM3Body.gaY.Length);
string m3GaStr = bMessage.BaToBlobStr(m3Ga);
string currentGaStr = bMessage.BaToBlobStr(sigmaSequenceCheck.currentGa);
// Check the ga is correct
bool gaCheck = CheckGa(currentGaStr, m3GaStr);
if (!gaCheck)
{
log.Debug("Invalid Message 3 ga");
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.Forbidden);
options.LogThrownException(e);
throw e;
}
// Check that the CMAC is correct
bool cmacCheck = CheckCmac(m3Received, m3GaStr);
if (!cmacCheck)
{
log.Debug("Invalid Message 3 CMAC");
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.Forbidden);
options.LogThrownException(e);
throw e;
}
string m3QuoteStr = bMessage.BaToBlobStr(m3Received.reqM3Body.quote);
if (String.IsNullOrEmpty(m3QuoteStr))
{
log.Debug("Message 3 Quote is NULL");
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.Forbidden);
options.LogThrownException(e);
throw e;
}
// Get MRSIGNER and ISVPRODID from the Quote to find the correct enclave type from Enclave.json
string MRSIGNERString = m3QuoteStr.Substring((int)Constants.QuoteInfo.MRSIGNEROffset * 2, Constants.QuoteInfo.MRSIGNERSize * 2); // MR Enclave String from Quote
log.InfoFormat("Quote came from enclave with MRSIGNER: {0}", MRSIGNERString);
ushort ISVPRODID = (ushort)BitConverter.ToInt16(bMessage.BlobStrToBa(m3QuoteStr.Substring((int)Constants.QuoteInfo.ISVPRODIDOffset * 2, 4)), 0);
log.DebugFormat("ISVPRODID:\t{0}", ISVPRODID);
sigmaSequenceCheck.SetEnclaveType(MRSIGNERString, ISVPRODID);
bool quoteOk = CheckQuoteOk(m3Received, m3QuoteStr, currentGaStr);
if (!quoteOk)
{
log.Debug("Invalid Message 3 Quote");
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.Forbidden);
options.LogThrownException(e);
throw e;
}
// Check whether using Debug quote or not
bool debugCheck = CheckDebug(m3QuoteStr);
if (!debugCheck)
{
log.Debug("Invalid Message 3 - Using Debug or Production quote when opposite is expected");
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.Forbidden);
options.LogThrownException(e);
throw e;
}
// Check Signature Type
bool sigTypeCheck = CheckSignatureType(m3QuoteStr);
if (!sigTypeCheck)
{
log.Debug("Invalid Message 3 Signature");
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.Forbidden);
options.LogThrownException(e);
throw e;
}
// Check ISV SVN
bool isvSVNCheck = CheckISVSVN(m3QuoteStr);
if (!isvSVNCheck)
{
log.Debug("Invalid Message 3 ISV SVN");
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.Forbidden);
options.LogThrownException(e);
throw e;
}
// Successful
// At this point, we know that a valid message 3 was received and we can send the quote to IAS.
// Complete the state transition.
M4ResponseMessage msg4Respsonse = new M4ResponseMessage();
try
{
sigmaSequenceCheck.m3Received = true;
Msg4Builder msgProcessor = new Msg4Builder();
msg4Respsonse = await msgProcessor.BuildMessage4(sigmaSequenceCheck, m3Received);
}
catch (HttpRequestException re)
{
options.LogCaughtErrorException(re);
log.Debug("Failed to create Message 4. " + re.Message);
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.InternalServerError);
options.LogThrownException(e);
throw e;
}
log.Debug("ProcessMessage3(.) returning.");
return(msg4Respsonse);
}
/// <summary>
/// Check that the Quote is correct
/// </summary>
/// <param name="m3Received">Message 3 from client</param>
/// <param name="m3QuoteStr">Message 3 quote string</param>
/// <param name="sigmaSequenceCheck">Service Provider Sequence (State) Check</param>
/// <param name="currentGaStr">Message 3 ECC Ga String</param>
/// <returns>Boolean whether the provided quote was valid</returns>
private bool CheckQuoteOk(M3RequestMessage m3Received, String m3QuoteStr, String currentGaStr)
{
log.Debug("CheckQuoteOk(.) started.");
if (m3Received == null || m3QuoteStr == null || currentGaStr == null)
{
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.InternalServerError);
options.LogThrownException(e);
throw e;
}
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// The Quote should match a pre-provisioned enclave measurement, and the quote signature should be valid.
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Ensure quote is within defined range
bool qSizeLimits = (m3Received.reqM3Body.quote.Length > MsgFieldLimits.UINT32_MINIMUM_QUOTE_SIZE && m3Received.reqM3Body.quote.Length < MsgFieldLimits.UINT32_PRACTICAL_SIZE_LIMIT);
if (!qSizeLimits)
{
log.Debug("Quote size is invalid: " + m3Received.reqM3Body.quote.Length + ". Expected range: " + MsgFieldLimits.UINT32_MINIMUM_QUOTE_SIZE + " to " + MsgFieldLimits.UINT32_PRACTICAL_SIZE_LIMIT);
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.BadRequest);
options.LogThrownException(e);
throw e;
}
// Look at the enclave measurement stored in Constants.QuoteInfo from the settings file.
// Assume the measurement is stored as a base 16 encoded string, but verify the input.
bool qMeasurementMatch = false;
bool qMeasurementRequired = false;
string mrEncString = m3QuoteStr.Substring((int)Constants.QuoteInfo.mrEncOffset * 2, Constants.QuoteInfo.mrEncSize * 2); // MR Enclave String from Quote
log.DebugFormat("m3 quote measurement: {0}", mrEncString);
log.DebugFormat("recorded quote measurement: {0}", sigmaSequenceCheck.enclaveType.MRENCLAVE);
// Check the stored quote string from user input by attempting to convert to byte array form.
if (!String.IsNullOrEmpty(sigmaSequenceCheck.enclaveType.MRENCLAVE))
{
qMeasurementRequired = true;
byte[] mrEnclaveTestBa = bMessage.BlobStrToBa(sigmaSequenceCheck.enclaveType.MRENCLAVE);
// Convert the MRenclave byte array back to string form to ensure uniform base16 Encoding from user input
sigmaSequenceCheck.enclaveType.MRENCLAVE = bMessage.BaToBlobStr(mrEnclaveTestBa);
qMeasurementMatch = String.Equals(mrEncString, sigmaSequenceCheck.enclaveType.MRENCLAVE, StringComparison.Ordinal);
log.DebugFormat("converted quote measurement: {0}", sigmaSequenceCheck.enclaveType.MRENCLAVE);
log.DebugFormat("quote compare result: {0}", qMeasurementMatch);
}
// Derive the "VK" key using VK = AES-CMAC(KDK, 0x01||’VK’||0x00||0x80 ||0x00)
byte[] VK = bMessage.KeyLabelToKey(Constants.VK, sigmaSequenceCheck.currentKDK);
// Compute a SHA-256 hash of (ga||gb||VK).
string currentGbStr = bMessage.BaToBlobStr(sigmaSequenceCheck.currentGb);
string vKstring = bMessage.BaToBlobStr(VK);
string gabvkStr = currentGaStr + currentGbStr + vKstring;
byte[] gabvkBa = bMessage.BlobStrToBa(gabvkStr);
byte[] gabvkHashBa = null;
// Klocwork issues related to qRptSha...
// Klocwork thinks tha this object is dereferenced before null check. However, if it is
// null, then an exception is thrown below, outside of our try-catch-finally block, and
// all other paths go through the try-catch-finally, where it gets properly disposed.
// It appears that klocwork somehow became confused in this code flow.
using (SHA256Cng qRptSha = new SHA256Cng())
{
if (qRptSha == null)
{
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.InternalServerError);
options.LogThrownException(e);
throw e;
}
try
{
gabvkHashBa = qRptSha.ComputeHash(gabvkBa);
string gabvkHashString = bMessage.BaToBlobStr(gabvkHashBa);
// Retrieve the non-zero (first 32) Bytes of the "REPORTDATA" field from the quote
string rptDataString = m3QuoteStr.Substring((int)Constants.QuoteInfo.reportDataOffset * 2, Constants.QuoteInfo.reportDataSize * 2);
bool qHashMatch = false;
log.DebugFormat("m3 (ga||gb||VK) hash: {0}", rptDataString);
log.DebugFormat("computed (ga||gb||VK) hash: {0}", gabvkHashString);
qHashMatch = String.Equals(rptDataString, gabvkHashString, StringComparison.Ordinal);
log.DebugFormat("hash compare result: {0}", qHashMatch);
// Evaluate the quote check conditions
if (qSizeLimits && qHashMatch && (qMeasurementMatch || !qMeasurementRequired))
{
log.Debug("CheckQuoteOk(.) returning true.");
return(true);
}
log.Debug("!!! Quote Check Failure !!!");
PrintQuote(m3QuoteStr);
}
catch (Exception e)
{
options.LogCaughtErrorException(e);
log.Debug("Error checking Quote. " + e.Message);
HttpResponseException newException = new HttpResponseException(System.Net.HttpStatusCode.InternalServerError);
options.LogThrownException(newException);
throw newException;
}
}
log.Debug("CheckQuoteOk(.) returning false.");
return(false);
}
/// <summary>
/// Retrieves the Client ID from the request
/// </summary>
/// <param name="request">Provisioning request</param>
/// <returns>String ID of the requesting client</returns>
public static string GetClientID(HttpRequestMessage request, string requestType)
{
log.DebugFormat("GetClientID({0}) started.", requestType);
// Note: requestType==null case is handled in code farther down.
if (request == null)
{
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.BadRequest);
options.LogThrownException(e);
throw e;
}
// Need to get Client state (id) information
var result = request.Content.ReadAsStringAsync();
string jsonMsgRequest = result.Result;
string ID = null;
try
{
switch (requestType)
{
case "Provision":
ProvisionRequestMessage pReceived = JsonConvert.DeserializeObject <ProvisionRequestMessage>(jsonMsgRequest);
ID = BitConverter.ToString(pReceived.reqHeader.nonce);
break;
case "Msg0":
M0RequestMessage m0Received = JsonConvert.DeserializeObject <M0RequestMessage>(jsonMsgRequest);
ID = BitConverter.ToString(m0Received.reqHeader.nonce);
break;
case "Msg1":
M1RequestMessage m1Received = JsonConvert.DeserializeObject <M1RequestMessage>(jsonMsgRequest);
ID = BitConverter.ToString(m1Received.reqHeader.nonce);
break;
case "Msg3":
M3RequestMessage m3Received = JsonConvert.DeserializeObject <M3RequestMessage>(jsonMsgRequest);
ID = BitConverter.ToString(m3Received.reqHeader.nonce);
break;
default:
{
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.InternalServerError);
options.LogThrownException(e);
throw e;
}
}
}
catch (Exception msgError)
{
options.LogCaughtErrorException(msgError);
log.DebugFormat("******* Message JSON Content Error: {0}\n", msgError);
HttpResponseException newException = new HttpResponseException(System.Net.HttpStatusCode.InternalServerError);
options.LogThrownException(newException);
throw newException;
}
if (ID != null)
{
ID = ID.Replace("-", "").Trim();
}
else
{
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.InternalServerError);
options.LogThrownException(e);
throw e;
}
log.DebugFormat("GetClientID({0}) returning.", requestType);
return(ID);
}
