/// <summary>
/// Process Message 1 and create Message 2
/// </summary>
/// <param name="Request">Client Provisioning request</param>
/// <param name="sigmaSequenceCheck">Service Provider Sequence (State) Check</param>
/// <returns>Message 2 content</returns>
public M2ResponseMessage ProcessMessage1(HttpRequestMessage Request, SpSequenceCheck sigmaSequenceCheck)
{
log.Debug("ProcessMessage1(.) started.");
if (Request == null)
{
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.BadRequest);
options.LogThrownException(e);
throw e;
}
if (sigmaSequenceCheck == null)
{
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.InternalServerError);
options.LogThrownException(e);
throw e;
}
// Check and parse Message 1
M1RequestMessage m1Received = VerifyMessage1IsValid(Request, sigmaSequenceCheck);
CalculateDiffieHellmanExchange(sigmaSequenceCheck, m1Received);
// Successful process of Message 1
// Create Message 2
Msg2Builder msgProcessor = new Msg2Builder();
M2ResponseMessage msg2Response = msgProcessor.BuildMessage2(sigmaSequenceCheck, m1Received, gidBaString, gbXLittleEndian, gbYLittleEndian, sigSPXLittleEndian, sigSPYLittleEndian, cMACsmk);
log.Debug("ProcessMessage1(.) returning.");
return(msg2Response);
}
//Build an M1 request
public void buildM1Request(out M1RequestMessage m1Req)
{
string request = Constants.Request;
var m1Msg = new M1RequestMessage(request);
var m1Body = new ReqMsg1Body();
m1Msg.reqHeader.nonce = Constants.sn1;
m1Body.pltfrmGid = Constants.sampleGid;
m1Body.gaX = Constants.sampleGaXba;
m1Body.gaY = Constants.sampleGaYba;
m1Msg.reqM1Body = m1Body;
m1Req = m1Msg;
return;
}
/// <summary>
/// Build Message 2
/// </summary>
/// <param name="sigmaSequenceCheck">Service Provider Sequence (State) Check</param>
/// <param name="m1Received">Message 1</param>
/// <returns>Message 2 Repsonse to Client</returns>
public M2ResponseMessage BuildMessage2(SpSequenceCheck sigmaSequenceCheck, M1RequestMessage m1Received,
String gidBaString, byte[] gbXLittleEndian, byte[] gbYLittleEndian, byte[] sigSPXLittleEndian, byte[] sigSPYLittleEndian, byte[] cMACsmk)
{
log.Debug("BuildMessage2(.) started.");
if (sigmaSequenceCheck == null || m1Received == null)
{
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.InternalServerError);
options.LogThrownException(e);
throw e;
}
// Update Client state
if (!sigmaSequenceCheck.UpdateState(Constants.SequenceState.Msg2))
{
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.PreconditionFailed);
options.LogThrownException(e);
throw e;
}
SetDiffieHellmanExchange(gidBaString, gbXLittleEndian, gbYLittleEndian, sigSPXLittleEndian, sigSPYLittleEndian, cMACsmk);
// Check that Diffie Hellman values are initialized
if (!initialized)
{
return(null);
}
log.Debug("Building message 2");
if (SpStartup.iasConnectionMgr.UseIAS)
{
// Connect to IAS for Signature Revocation List
BuildIASMessage2(sigmaSequenceCheck);
}
else
{
// Simulate IAS
// For testing the SGX client connection only, override the IAS connection settings by setting "UseIAS" to false.
// This setting should be temporary, and once the SGX messaging is working, set "UseIAS" to true.
BuildNonIasMessage2(sigmaSequenceCheck);
}
log.Debug("BuildMessage2(.) returning.");
return(msg2);
}
/// <summary>
/// Calculate values for Diffie Hellman values
/// </summary>
/// <param name="sigmaSequenceCheck">Service Provider Sequence (State) Check</param>
/// <param name="m1Received">Message 1</param>
private void CalculateDiffieHellmanExchange(SpSequenceCheck sigmaSequenceCheck, M1RequestMessage m1Received)
{
log.Debug("CalculateDiffieHellmanExchange(..) started.");
if (sigmaSequenceCheck == null || m1Received == null)
{
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.InternalServerError);
options.LogThrownException(e);
throw e;
}
// (Intel Performance Primitives) IPP Wrapper
ippApiWrapper ippWrapper = new ippApiWrapper();
// Process message 1 and build the message 2 response.
// Capture the GID and Base16 encode the gid field per the IAS API specificaiton:
// "{gid} = Base 16-encoded representation of QE EPID group ID encoded as a Little Endian integer".
// NOTE: This conversion assumes that the GID was sent without modification in the "pltfrmGid" message field.
byte[] gidBa = m1Received.reqM1Body.pltfrmGid;
// Required that the GID is supplied with no conversions from the SGX client and reverse the byte order
// to convert to Big Endian integer for use later in the routine when encoding as a Base 16 string.
Array.Reverse(gidBa);
gidBaString = bMessage.BaToBlobStr(gidBa);
// In crypto terms, a = Alice (Client) and b = Bob (Service provider)
// so ga = secret shared by client and gb = secret shared by service provide
gaLittleEndianstr = m1Received.GetGaString(); // Received in Little Endian format
gaXLittleEndianstr = "";
// ga = gaX|gaY -- take the first half of ga to get gaX
if (gaLittleEndianstr != null)
{
gaXLittleEndianstr = gaLittleEndianstr.Substring(0, gaLittleEndianstr.Length / 2);
}
gaXLittleEndian = bMessage.BlobStrToBa(gaXLittleEndianstr);
gaXBigEndian = bMessage.BlobStrToBa(gaXLittleEndianstr);
Array.Reverse(gaXBigEndian, 0, gaXBigEndian.Length);
gaXBigEndianstr = bMessage.BaToBlobStr(gaXBigEndian);
gaYLittleEndianstr = "";
if (gaLittleEndianstr != null)
{
gaYLittleEndianstr = gaLittleEndianstr.Substring(gaLittleEndianstr.Length / 2);
}
gaYLittleEndian = bMessage.BlobStrToBa(gaYLittleEndianstr);
gaYBigEndian = bMessage.BlobStrToBa(gaYLittleEndianstr);
Array.Reverse(gaYBigEndian, 0, gaYBigEndian.Length);
gaYBigEndianstr = bMessage.BaToBlobStr(gaYBigEndian);
// Capture the Little Endian representation of ga for later message checking
sigmaSequenceCheck.currentGa = bMessage.BlobStrToBa(gaXLittleEndianstr + gaYLittleEndianstr);
{
// Use IPP or some other alternative if the user configuration does not select MS bcrypt for Diffie-Hellman key exchange.
// NOTE: The use of IPP allows for the use of the standard wrapper functions in the SGX SDK.
log.Debug("Calling IPP Wrapper for Diffie-Hellman key exchange...");
ippWrapper.InitDiffieHellman();
ippWrapper.GetDHPublicKey(ref gbXLittleEndian, ref gbYLittleEndian);
gbXLittleEndianstr = bMessage.BaToBlobStr(gbXLittleEndian);
gbYLittleEndianstr = bMessage.BaToBlobStr(gbYLittleEndian);
gbLittleEndianStr = string.Concat(gbXLittleEndianstr, gbYLittleEndianstr);
sigmaSequenceCheck.currentGb = bMessage.BlobStrToBa(gbXLittleEndianstr + gbYLittleEndianstr);
log.DebugFormat("Server Public key: {0}", gbLittleEndianStr);
// Derive the shared key
byte[] sharedKey256 = new byte[Constants.SharedKeylen];
ippWrapper.GetDHSharedSecret(gaXLittleEndian, gaYLittleEndian, ref sharedKey256);
derivedKeyStr = bMessage.BaToBlobStr(sharedKey256);
log.DebugFormat("Shared secret: {0}", derivedKeyStr);
}
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Use the full 256 bits of the derived DH key to further derive our smk
//SMK is derived from the Diffie-Hellman shared secret elliptic curve field element
// between the service provider and the
// application enclave:
// First compute Key Definition Key: KDK = AES-CMAC(0x00, gab x-coordinate)
// Then SMK = AES-CMAC ( KDK, 0x01||’SMK’||0x00||0x80||0x00)
byte[] derivedKeyBa = bMessage.BlobStrToBa(derivedKeyStr);
// Store the KDK for further key derivation.
sigmaSequenceCheck.currentKDK = cmacAES.Value(MsgInitValues.DS_ZERO_BA16, derivedKeyBa);
// Store the SMK for the current session for use in processing message 3
sigmaSequenceCheck.currentSmk = bMessage.KeyLabelToKey(Constants.SMK, sigmaSequenceCheck.currentKDK);
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Build each term by retrieving elements,
// concatenating, converting and performing crypto operations.
string gbgaStr = gbXLittleEndianstr + gbYLittleEndianstr + gaXLittleEndianstr + gaYLittleEndianstr;
byte[] gbgaBa = bMessage.BlobStrToBa(gbgaStr); // gb||ga
// Sign the gb||ga element Service Provider -- we use sigSP to notate this Service Provider signature
// Get the Private Key from the settings file
byte[] privateKey;
try
{
privateKey = Constants.spPrivKeyBlob;// spPrivKeyBlob;
}
catch (Exception e)
{
options.LogCaughtErrorException(e);
log.Debug("Failed to get private key: " + e.Message);
HttpResponseException newException = new HttpResponseException(System.Net.HttpStatusCode.InternalServerError);
options.LogThrownException(newException);
throw newException;
}
CngKey signSgxKey = CngKey.Import(privateKey, CngKeyBlobFormat.EccPrivateBlob);
ECDsaCng ecDsaSig = new ECDsaCng(signSgxKey); // Elliptic Curve Digital Signature Algorithm, Signature
ecDsaSig.HashAlgorithm = CngAlgorithm.Sha256;
byte[] sigSPpubKey = ecDsaSig.Key.Export(CngKeyBlobFormat.EccPublicBlob);
string sigSPpubKeyBlob = "{ 0x" + BitConverter.ToString(sigSPpubKey).Replace("-", ", 0x") + " }";
byte[] sigSP = ecDsaSig.SignData(gbgaBa); // Input is LittleEndian, but output is BigEndian
string sigSPstring = bMessage.BaToBlobStr(sigSP);
// Separate the X and Y components of the signature -- Big Endian at this point
string sigSPXBigEndianstr = sigSPstring.Substring(0, (sigSPstring.Length / 2));
byte[] sigSPXBigEndian = bMessage.BlobStrToBa(sigSPXBigEndianstr);
string sigSPYBigEndianstr = sigSPstring.Substring(sigSPstring.Length / 2);
byte[] sigSPYBigEndian = bMessage.BlobStrToBa(sigSPYBigEndianstr);
// Swap the byte order of the signed data back to Little Endian and convert to combined string (X|Y)
sigSPXLittleEndian = sigSPXBigEndian.Reverse().ToArray();
string sigSPXLittleEndianstr = bMessage.BaToBlobStr(sigSPXLittleEndian);
sigSPYLittleEndian = sigSPYBigEndian.Reverse().ToArray();
string sigSPYLittleEndianstr = bMessage.BaToBlobStr(sigSPYLittleEndian);
string sigSPLittleEndianstring = sigSPXLittleEndianstr + sigSPYLittleEndianstr;
// sigSPLittleEndianstring is in Little Endian format as required, ready to send to client
// Get the signature link type
try
{
if (SpStartup.iasConnectionMgr.LinkableQuotes)
{
log.Debug("Using Linkable Quotes");
// If the SP policy setting dictates the use of linkable quotes, explicitly
// overwrite the default value in the sltype container.
// Otherwise, the default value will be an un-linkable quote type.
System.Buffer.BlockCopy(Constants.linkableBa, 0, Constants.sltype, 0, Constants.linkableBa.Length);
}
}
catch (Exception e)
{
options.LogCaughtErrorException(e);
log.Debug("Failed to get Linked Quote: " + e.Message);
HttpResponseException newException = new HttpResponseException(System.Net.HttpStatusCode.InternalServerError);
options.LogThrownException(newException);
throw newException;
}
string sigTypeStr = bMessage.BaToBlobStr(Constants.sltype);
string kdfIdStr = bMessage.BaToBlobStr(Constants.kdfId);
string gbSpidSigSPstring = gbLittleEndianStr + bMessage.BaToBlobStr(SpStartup.iasConnectionMgr.SPID) + sigTypeStr + kdfIdStr + sigSPLittleEndianstring;
byte[] macBlob = bMessage.BlobStrToBa(gbSpidSigSPstring);
// Compute the CMAKsmk of (gb||SPID||Type||KDF-ID||SigSP(gb||ga))
cMACsmk = cmacAES.Value(sigmaSequenceCheck.currentSmk, macBlob);
string cMACsmkStr = bMessage.BaToBlobStr(cMACsmk);
ecDsaSig.Dispose();
log.Debug("CalculateDiffieHellmanExchange(..) returning.");
}
/// <summary>
/// Verify that Message 1 is valid
/// </summary>
/// <param name="Request">Client Message 1 Response</param>
/// <param name="sigmaSequenceCheck">Service Provider Sequence (State) Check</param>
/// <returns>Parsed and validated Message 1</returns>
private M1RequestMessage VerifyMessage1IsValid(HttpRequestMessage request, SpSequenceCheck sigmaSequenceCheck)
{
log.Debug("VerifyMessage1IsValid(.) started.");
if (request == null || sigmaSequenceCheck == null)
{
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.InternalServerError);
options.LogThrownException(e);
throw e;
}
// Update Client state
if (!sigmaSequenceCheck.UpdateState(Constants.SequenceState.Msg1))
{
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.PreconditionFailed);
options.LogThrownException(e);
throw e;
}
// Check m1 and if valid, process, create a nonce, get the sigRL and return m2.
// M1 = msg1 = m1 = s1 = ga||GID
var result = request.Content.ReadAsStringAsync();
string jsonMsg1Request = result.Result;
M1RequestMessage m1Received = new M1RequestMessage();
try
{
m1Received = JsonConvert.DeserializeObject <M1RequestMessage>(jsonMsg1Request);
}
catch (Exception msg1reqError)
{
options.LogCaughtErrorException(msg1reqError);
log.DebugFormat("******* Message 1 JSON Content Error: {0}", msg1reqError);
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.InternalServerError);
options.LogThrownException(e);
throw e;
}
string m1ReceivedString = m1Received.GetMsgString();
log.Info("******* Received M1 Request");
log.DebugFormat("{0}{1}", request.Headers, jsonMsg1Request);
log.DebugFormat("M1 Base 16 Encoded String: {0}", m1ReceivedString);
// Check the nonce and the base16 encoded length of the inbound request
bool nonceCheckSuccess = false;
try
{
log.Debug("Checking nonce");
nonceCheckSuccess = sigmaSequenceCheck.currentNonce.SequenceEqual(m1Received.reqHeader.nonce);
}
catch (Exception e)
{
options.LogCaughtErrorException(e);
log.DebugFormat("****Message 1 Nonce Error: {0}", e);
HttpResponseException newException = new HttpResponseException(System.Net.HttpStatusCode.InternalServerError);
options.LogThrownException(newException);
throw newException;
}
if (!nonceCheckSuccess)
{
log.Debug("Msg1 Nonce check failed");
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.Forbidden);
options.LogThrownException(e);
throw e;
}
// Compare the reported length against the actual length (base16 string length/2)
// Could BigEndian a replay attempt if the nonce field does not match.
// Could also be other tampering if other fields do not pass checks.
// Restart the session, and reject the request.
if (!(BitConverter.ToUInt32(m1Received.reqHeader.msgLength, 0) == (m1ReceivedString.Length / 2)))
{
log.Debug("Msg1 Message length check failed");
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.Forbidden);
options.LogThrownException(e);
throw e;
}
if (m1Received.reqM1Body.gaX.SequenceEqual(MsgInitValues.DS_EMPTY_BA32))
{
log.Debug("Msg1 GaX check failed");
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.Forbidden);
options.LogThrownException(e);
throw e;
}
if (m1Received.reqM1Body.gaY.SequenceEqual(MsgInitValues.DS_EMPTY_BA32))
{
log.Debug("Msg1 GaY check failed");
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.Forbidden);
options.LogThrownException(e);
throw e;
}
if (m1Received.reqM1Body.pltfrmGid.SequenceEqual(MsgInitValues.DS_EMPTY_BA32))
{
log.Debug("Msg1 Platform Group ID check failed");
HttpResponseException e = new HttpResponseException(System.Net.HttpStatusCode.Forbidden);
options.LogThrownException(e);
throw e;
}
log.Debug("VerifyMessage1IsValid(.) returning.");
return(m1Received);
}
/// <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);
}
