/// <summary>
/// This callback function provides authorization in plain text
/// </summary>
static public void PolicySecretCallback(
PolicyTree policyTree,
TpmPolicySecret ace,
out SessionBase authorizingSession,
out TpmHandle authorizedEntityHandle,
out bool flushAuthEntity)
{
authorizingSession = _publicAuthorizationValue;
authorizedEntityHandle = _publicSealedObjectHandle;
flushAuthEntity = false;
}
/// <summary>
/// This callback function provides authorization in the form of an HMAC session
/// </summary>
static public void PolicySecretCallback2(
PolicyTree policyTree,
TpmPolicySecret ace,
out SessionBase authorizingSession,
out TpmHandle authorizedEntityHandle,
out bool flushAuthEntity)
{
AuthSession s0 = _sharedTpm.StartAuthSessionEx(TpmSe.Hmac, TpmAlgId.Sha1);
authorizingSession = s0;
authorizedEntityHandle = _publicSealedObjectHandle;
flushAuthEntity = true;
}
/// <summary>
/// Activates an identity key within the TPM device.
/// </summary>
/// <param name="encryptedKey">The encrypted identity key.</param>
public override void ActivateIdentityKey(byte[] encryptedKey)
{
if (Logging.IsEnabled)
{
Logging.Enter(this, $"{encryptedKey}", nameof(ActivateIdentityKey));
}
Destroy();
// Take the pieces out of the container
var m = new Marshaller(encryptedKey, DataRepresentation.Tpm);
Tpm2bIdObject cred2b = m.Get <Tpm2bIdObject>();
byte[] encryptedSecret = new byte[m.Get <ushort>()];
encryptedSecret = m.GetArray <byte>(encryptedSecret.Length, "encryptedSecret");
TpmPrivate dupBlob = m.Get <TpmPrivate>();
byte[] encWrapKey = new byte[m.Get <ushort>()];
encWrapKey = m.GetArray <byte>(encWrapKey.Length, "encWrapKey");
UInt16 pubSize = m.Get <UInt16>();
_idKeyPub = m.Get <TpmPublic>();
byte[] cipherText = new byte[m.Get <ushort>()];
cipherText = m.GetArray <byte>(cipherText.Length, "uriInfo");
// Setup the authorization session for the EK
var policyNode = new TpmPolicySecret(TpmHandle.RhEndorsement, false, 0, Array.Empty <byte>(), Array.Empty <byte>());
var policy = new PolicyTree(_ekPub.nameAlg);
policy.SetPolicyRoot(policyNode);
AuthSession ekSession = _tpm2.StartAuthSessionEx(TpmSe.Policy, _ekPub.nameAlg);
ekSession.RunPolicy(_tpm2, policy);
// Perform the activation
ekSession.Attrs &= ~SessionAttr.ContinueSession;
_activationSecret = _tpm2[Array.Empty <byte>(), ekSession].ActivateCredential(
new TpmHandle(TPM_20_SRK_HANDLE),
new TpmHandle(TPM_20_EK_HANDLE),
cred2b.credential,
encryptedSecret);
TpmPrivate importedKeyBlob = _tpm2.Import(
new TpmHandle(TPM_20_SRK_HANDLE),
_activationSecret,
_idKeyPub,
dupBlob,
encWrapKey,
new SymDefObject(TpmAlgId.Aes, 128, TpmAlgId.Cfb));
_idKeyHandle = _tpm2.Load(new TpmHandle(TPM_20_SRK_HANDLE), importedKeyBlob, _idKeyPub);
// Persist the key in NV
TpmHandle hmacKeyHandle = new TpmHandle(AIOTH_PERSISTED_KEY_HANDLE);
_tpm2.EvictControl(new TpmHandle(TpmRh.Owner), _idKeyHandle, hmacKeyHandle);
// Unload the transient copy from the TPM
_tpm2.FlushContext(_idKeyHandle);
_idKeyHandle = hmacKeyHandle;
if (Logging.IsEnabled)
{
Logging.Exit(this, $"{encryptedKey}", nameof(ActivateIdentityKey));
}
}
/// <summary>
/// Activates a symmetric identity within the Hardware Security Module.
/// </summary>
/// <param name="activation">The authentication challenge key supplied by the service.</param>
public override void ActivateSymmetricIdentity(byte[] activation)
{
Destroy();
// Take the pieces out of the container
var m = new Marshaller(activation, DataRepresentation.Tpm);
byte[] credentialBlob = new byte[m.Get <ushort>()];
credentialBlob = m.GetArray <byte>(credentialBlob.Length, "credentialBlob");
byte[] encryptedSecret = new byte[m.Get <ushort>()];
encryptedSecret = m.GetArray <byte>(encryptedSecret.Length, "encryptedSecret");
TpmPrivate dupBlob = m.Get <TpmPrivate>();
byte[] encWrapKey = new byte[m.Get <ushort>()];
encWrapKey = m.GetArray <byte>(encryptedSecret.Length, "encWrapKey");
UInt16 pubSize = m.Get <UInt16>();
_idKeyPub = m.Get <TpmPublic>();
byte[] cipherText = new byte[m.Get <ushort>()];
cipherText = m.GetArray <byte>(cipherText.Length, "uriInfo");
// Setup the authorization session for the EK
var policyNode = new TpmPolicySecret(
TpmHandle.RhEndorsement, _ekAuth ?? Array.Empty <byte>(),
new AuthValue(),
false,
0,
Array.Empty <byte>(),
Array.Empty <byte>());
var policy = new PolicyTree(_ekPub.nameAlg);
policy.SetPolicyRoot(policyNode);
AuthSession ekSession = _tpm2.StartAuthSessionEx(TpmSe.Policy, _ekPub.nameAlg);
ekSession.RunPolicy(_tpm2, policy);
// Perform the activation
ekSession.Attrs &= ~SessionAttr.ContinueSession;
_activationSecret = _tpm2[Array.Empty <byte>(), ekSession].ActivateCredential(
new TpmHandle(TPM_20_SRK_HANDLE),
new TpmHandle(TPM_20_EK_HANDLE),
credentialBlob,
encryptedSecret);
TpmPrivate importedKeyBlob = _tpm2.Import(
new TpmHandle(TPM_20_SRK_HANDLE),
_activationSecret,
_idKeyPub,
dupBlob,
encWrapKey,
new SymDefObject(TpmAlgId.Aes, 128, TpmAlgId.Cfb));
_idKeyHandle = _tpm2.Load(new TpmHandle(TPM_20_SRK_HANDLE), importedKeyBlob, _idKeyPub);
// Persist the key in NV
TpmHandle hmacKeyHandle = new TpmHandle(AIOTH_PERSISTED_KEY_HANDLE);
_tpm2.EvictControl(new TpmHandle(TpmRh.Owner), _idKeyHandle, hmacKeyHandle);
// Unload the transient copy from the TPM
_tpm2.FlushContext(_idKeyHandle);
_idKeyHandle = hmacKeyHandle;
// Unwrap the URI
byte[] clearText = SymmCipher.Decrypt(
new SymDefObject(TpmAlgId.Aes, 128, TpmAlgId.Cfb),
_activationSecret,
new byte[16],
cipherText);
UnicodeEncoding unicode = new UnicodeEncoding();
string uriData = unicode.GetString(clearText);
int idx = uriData.IndexOf('/');
if (idx > 0)
{
string hostName = uriData.Substring(0, idx);
string deviceId = uriData.Substring(idx + 1);
// Persist the URI
ProvisionUri(hostName, deviceId);
}
}
