// NOTE: This method represents a theoretical way to use a U2F-compliant token
// to produce the result of the WebAuthn GetAssertion method. The exact mapping
// of U2F data fields to WebAuthn data fields is still a matter of ongoing
// discussion, and this should not be taken as anything but a point-in- time
// possibility.
void
WebAuthentication::U2FAuthGetAssertion(const RefPtr<AssertionRequest>& aRequest,
const Authenticator& aToken, CryptoBuffer& aRpIdHash,
const nsACString& aClientData, CryptoBuffer& aClientDataHash,
nsTArray<CryptoBuffer>& aAllowList,
const WebAuthnExtensions& aExtensions)
{
MOZ_LOG(gWebauthLog, LogLevel::Debug, ("U2FAuthGetAssertion"));
// 4.1.2.7.e Add an entry to issuedRequests, corresponding to this request.
aRequest->AddActiveToken(__func__);
// 4.1.2.8 While issuedRequests is not empty, perform the following actions
// depending upon the adjustedTimeout timer and responses from the
// authenticators:
// 4.1.2.8.a If the timer for adjustedTimeout expires, then for each entry
// in issuedRequests invoke the authenticatorCancel operation on that
// authenticator and remove its entry from the list.
for (CryptoBuffer& allowedCredential : aAllowList) {
bool isRegistered = false;
nsresult rv = aToken->IsRegistered(allowedCredential.Elements(),
allowedCredential.Length(),
&isRegistered);
// 4.1.2.8.b If any authenticator returns a status indicating that the user
// cancelled the operation, delete that authenticator’s entry from
// issuedRequests. For each remaining entry in issuedRequests invoke the
// authenticatorCancel operation on that authenticator, and remove its entry
// from the list.
// 4.1.2.8.c If any authenticator returns an error status, delete the
// corresponding entry from issuedRequests.
if (NS_WARN_IF(NS_FAILED(rv))) {
aRequest->SetFailure(rv);
return;
}
if (!isRegistered) {
continue;
}
// Sign
uint8_t* buffer;
uint32_t bufferlen;
rv = aToken->Sign(aRpIdHash.Elements(), aRpIdHash.Length(),
aClientDataHash.Elements(), aClientDataHash.Length(),
allowedCredential.Elements(), allowedCredential.Length(),
&buffer, &bufferlen);
if (NS_WARN_IF(NS_FAILED(rv))) {
aRequest->SetFailure(rv);
return;
}
MOZ_ASSERT(buffer);
CryptoBuffer signatureData;
if (NS_WARN_IF(!signatureData.Assign(buffer, bufferlen))) {
free(buffer);
aRequest->SetFailure(NS_ERROR_OUT_OF_MEMORY);
return;
}
free(buffer);
// 4.1.2.8.d If any authenticator returns success:
// 4.1.2.8.d.1 Remove this authenticator’s entry from issuedRequests.
// 4.1.2.8.d.2 Create a new WebAuthnAssertion object named value and
// populate its fields with the values returned from the authenticator as
// well as the clientDataJSON computed earlier.
CryptoBuffer clientDataBuf;
if (!clientDataBuf.Assign(aClientData)) {
aRequest->SetFailure(NS_ERROR_OUT_OF_MEMORY);
return;
}
CryptoBuffer authenticatorDataBuf;
rv = U2FAssembleAuthenticatorData(authenticatorDataBuf, aRpIdHash,
signatureData);
if (NS_WARN_IF(NS_FAILED(rv))) {
aRequest->SetFailure(rv);
return;
}
RefPtr<ScopedCredential> credential = new ScopedCredential(this);
credential->SetType(ScopedCredentialType::ScopedCred);
credential->SetId(allowedCredential);
AssertionPtr assertion = new WebAuthnAssertion(this);
assertion->SetCredential(credential);
assertion->SetClientData(clientDataBuf);
assertion->SetAuthenticatorData(authenticatorDataBuf);
assertion->SetSignature(signatureData);
// 4.1.2.8.d.3 For each remaining entry in issuedRequests invoke the
// authenticatorCancel operation on that authenticator and remove its entry
// from the list.
// 4.1.2.8.d.4 Resolve promise with value and terminate this algorithm.
aRequest->SetSuccess(assertion);
return;
}
// 4.1.2.9 Reject promise with a DOMException whose name is "NotAllowedError",
// and terminate this algorithm.
aRequest->SetFailure(NS_ERROR_DOM_NOT_ALLOWED_ERR);
}
// NOTE: This method represents a theoretical way to use a U2F-compliant token
// to produce the result of the WebAuthn MakeCredential method. The exact
// mapping of U2F data fields to WebAuthn data fields is still a matter of
// ongoing discussion, and this should not be taken as anything but a point-in-
// time possibility.
void
WebAuthentication::U2FAuthMakeCredential(
const RefPtr<CredentialRequest>& aRequest,
const Authenticator& aToken, CryptoBuffer& aRpIdHash,
const nsACString& aClientData, CryptoBuffer& aClientDataHash,
const Account& aAccount,
const nsTArray<ScopedCredentialParameters>& aNormalizedParams,
const Optional<Sequence<ScopedCredentialDescriptor>>& aExcludeList,
const WebAuthnExtensions& aExtensions)
{
MOZ_LOG(gWebauthLog, LogLevel::Debug, ("U2FAuthMakeCredential"));
aRequest->AddActiveToken(__func__);
// 5.1.1 When this operation is invoked, the authenticator must perform the
// following procedure:
// 5.1.1.a Check if all the supplied parameters are syntactically well-
// formed and of the correct length. If not, return an error code equivalent
// to UnknownError and terminate the operation.
if ((aRpIdHash.Length() != SHA256_LENGTH) ||
(aClientDataHash.Length() != SHA256_LENGTH)) {
aRequest->SetFailure(NS_ERROR_DOM_UNKNOWN_ERR);
return;
}
// 5.1.1.b Check if at least one of the specified combinations of
// ScopedCredentialType and cryptographic parameters is supported. If not,
// return an error code equivalent to NotSupportedError and terminate the
// operation.
bool isValidCombination = false;
for (size_t a = 0; a < aNormalizedParams.Length(); ++a) {
if (aNormalizedParams[a].mType == ScopedCredentialType::ScopedCred &&
aNormalizedParams[a].mAlgorithm.IsString() &&
aNormalizedParams[a].mAlgorithm.GetAsString().EqualsLiteral(
WEBCRYPTO_NAMED_CURVE_P256)) {
isValidCombination = true;
break;
}
}
if (!isValidCombination) {
aRequest->SetFailure(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
return;
}
// 5.1.1.c Check if a credential matching any of the supplied
// ScopedCredential identifiers is present on this authenticator. If so,
// return an error code equivalent to NotAllowedError and terminate the
// operation.
if (aExcludeList.WasPassed()) {
const Sequence<ScopedCredentialDescriptor>& list = aExcludeList.Value();
for (const ScopedCredentialDescriptor& scd : list) {
bool isRegistered = false;
uint8_t *data;
uint32_t len;
// data is owned by the Descriptor, do don't free it here.
if (NS_FAILED(ScopedCredentialGetData(scd, &data, &len))) {
aRequest->SetFailure(NS_ERROR_DOM_UNKNOWN_ERR);
return;
}
nsresult rv = aToken->IsRegistered(data, len, &isRegistered);
if (NS_WARN_IF(NS_FAILED(rv))) {
aRequest->SetFailure(rv);
return;
}
if (isRegistered) {
aRequest->SetFailure(NS_ERROR_DOM_NOT_ALLOWED_ERR);
return;
}
}
}
// 5.1.1.d Prompt the user for consent to create a new credential. The
// prompt for obtaining this consent is shown by the authenticator if it has
// its own output capability, or by the user agent otherwise. If the user
// denies consent, return an error code equivalent to NotAllowedError and
// terminate the operation.
// 5.1.1.d Once user consent has been obtained, generate a new credential
// object
// 5.1.1.e If any error occurred while creating the new credential object,
// return an error code equivalent to UnknownError and terminate the
// operation.
// 5.1.1.f Process all the supported extensions requested by the client, and
// generate an attestation statement. If no authority key is available to
// sign such an attestation statement, then the authenticator performs self
// attestation of the credential with its own private key. For more details
// on attestation, see §5.3 Credential Attestation Statements.
// No extensions are supported
// 4.1.1.11 While issuedRequests is not empty, perform the following actions
// depending upon the adjustedTimeout timer and responses from the
// authenticators:
// 4.1.1.11.a If the adjustedTimeout timer expires, then for each entry in
// issuedRequests invoke the authenticatorCancel operation on that
// authenticator and remove its entry from the list.
uint8_t* buffer;
uint32_t bufferlen;
nsresult rv = aToken->Register(aRpIdHash.Elements(), aRpIdHash.Length(),
aClientDataHash.Elements(),
aClientDataHash.Length(), &buffer, &bufferlen);
// 4.1.1.11.b If any authenticator returns a status indicating that the user
// cancelled the operation, delete that authenticator’s entry from
// issuedRequests. For each remaining entry in issuedRequests invoke the
// authenticatorCancel operation on that authenticator and remove its entry
// from the list.
// 4.1.1.11.c If any authenticator returns an error status, delete the
// corresponding entry from issuedRequests.
if (NS_WARN_IF(NS_FAILED(rv))) {
aRequest->SetFailure(NS_ERROR_DOM_UNKNOWN_ERR);
return;
}
MOZ_ASSERT(buffer);
CryptoBuffer regData;
if (NS_WARN_IF(!regData.Assign(buffer, bufferlen))) {
free(buffer);
aRequest->SetFailure(NS_ERROR_OUT_OF_MEMORY);
return;
}
free(buffer);
// Decompose the U2F registration packet
CryptoBuffer pubKeyBuf;
CryptoBuffer keyHandleBuf;
CryptoBuffer attestationCertBuf;
CryptoBuffer signatureBuf;
rv = U2FDecomposeRegistrationResponse(regData, pubKeyBuf, keyHandleBuf,
attestationCertBuf, signatureBuf);
if (NS_WARN_IF(NS_FAILED(rv))) {
aRequest->SetFailure(rv);
return;
}
// Sign the aClientDataHash explicitly to get the format needed for
// the AuthenticatorData parameter of WebAuthnAttestation. This might
// be temporary while the spec settles down how to incorporate U2F.
rv = aToken->Sign(aRpIdHash.Elements(), aRpIdHash.Length(),
aClientDataHash.Elements(), aClientDataHash.Length(),
keyHandleBuf.Elements(), keyHandleBuf.Length(), &buffer,
&bufferlen);
if (NS_WARN_IF(NS_FAILED(rv))) {
aRequest->SetFailure(rv);
return;
}
MOZ_ASSERT(buffer);
CryptoBuffer signatureData;
if (NS_WARN_IF(!signatureData.Assign(buffer, bufferlen))) {
free(buffer);
aRequest->SetFailure(NS_ERROR_OUT_OF_MEMORY);
return;
}
free(buffer);
CryptoBuffer clientDataBuf;
if (!clientDataBuf.Assign(aClientData)) {
aRequest->SetFailure(NS_ERROR_OUT_OF_MEMORY);
return;
}
CryptoBuffer authenticatorDataBuf;
rv = U2FAssembleAuthenticatorData(authenticatorDataBuf, aRpIdHash,
signatureData);
if (NS_WARN_IF(NS_FAILED(rv))) {
aRequest->SetFailure(rv);
return;
}
// 4.1.1.11.d If any authenticator indicates success:
// 4.1.1.11.d.1 Remove this authenticator’s entry from issuedRequests.
// 4.1.1.11.d.2 Create a new ScopedCredentialInfo object named value and
// populate its fields with the values returned from the authenticator as well
// as the clientDataJSON computed earlier.
RefPtr<ScopedCredential> credential = new ScopedCredential(this);
credential->SetType(ScopedCredentialType::ScopedCred);
credential->SetId(keyHandleBuf);
RefPtr<WebAuthnAttestation> attestation = new WebAuthnAttestation(this);
attestation->SetFormat(NS_LITERAL_STRING("u2f"));
attestation->SetClientData(clientDataBuf);
attestation->SetAuthenticatorData(authenticatorDataBuf);
attestation->SetAttestation(regData);
CredentialPtr info = new ScopedCredentialInfo(this);
info->SetCredential(credential);
info->SetAttestation(attestation);
// 4.1.1.11.d.3 For each remaining entry in issuedRequests invoke the
// authenticatorCancel operation on that authenticator and remove its entry
// from the list.
// 4.1.1.11.d.4 Resolve promise with value and terminate this algorithm.
aRequest->SetSuccess(info);
}