feat: add resident key protocol option (#13)

Adds the residentKey protocol option which is part of Webauthn Level 2.

protocol/authenticator.go

@@ -50,7 +50,7 @@ type AttestedCredentialData struct {
  CredentialPublicKey []byte `json:"public_key"`
 }
 
-// AuthenticatorAttachment https://www.w3.org/TR/webauthn/#platform-attachment
+// AuthenticatorAttachment https://www.w3.org/TR/webauthn/#dom-authenticatorselectioncriteria-authenticatorattachment
 type AuthenticatorAttachment string
 
 const (
@@ -65,6 +65,21 @@ const (
  CrossPlatform AuthenticatorAttachment = "cross-platform"
 )
 
+// ResidentKeyRequirement https://www.w3.org/TR/webauthn/#dom-authenticatorselectioncriteria-residentkey
+type ResidentKeyRequirement string
+
+const (
+ // ResidentKeyRequirementDiscouraged indicates to the client we do not want a discoverable credential. This is the default.
+ ResidentKeyRequirementDiscouraged ResidentKeyRequirement = "discouraged"
+
+ // ResidentKeyRequirementPreferred indicates to the client we would prefer a discoverable credential.
+ ResidentKeyRequirementPreferred ResidentKeyRequirement = "preferred"
+
+ // ResidentKeyRequirementRequired indicates to the client we require a discoverable credential and that it should
+ // fail if the credential does not support this feature.
+ ResidentKeyRequirementRequired ResidentKeyRequirement = "required"
+)
+
 // Authenticators may implement various transports for communicating with clients. This enumeration defines
 // hints as to how clients might communicate with a particular authenticator in order to obtain an assertion
 // for a specific credential. Note that these hints represent the WebAuthn Relying Party's best belief as to
@@ -237,8 +252,8 @@ func ResidentKeyRequired() *bool {
  return &required
 }
 
-// ResidentKeyUnrequired - Do not require that the private key be resident to the client device.
-func ResidentKeyUnrequired() *bool {
+// ResidentKeyNotRequired - Do not require that the private key be resident to the client device.
+func ResidentKeyNotRequired() *bool {
  required := false
  return &required
 }

protocol/options.go

@@ -91,6 +91,11 @@ type AuthenticatorSelection struct {
  // credentials. If the parameter is set to true, the authenticator MUST create a client-side-resident
  // public key credential source when creating a public key credential.
  RequireResidentKey *bool `json:"requireResidentKey,omitempty"`
+
+ // ResidentKey this member describes the Relying Party's requirements regarding resident
+ // credentials per Webauthn Level 2.
+ ResidentKey ResidentKeyRequirement `json:"residentKey,omitempty"`
+
  // UserVerification This member describes the Relying Party's requirements regarding user verification for
  // the create() operation. Eligible authenticators are filtered to only those capable of satisfying this
  // requirement.

webauthn/authenticator_test.go

@@ -127,12 +127,12 @@ func TestSelectAuthenticator(t *testing.T) {
  {"Generate Correct Authenticator Selection",
  args{
  att: "platform",
- rrk: p.ResidentKeyUnrequired(),
+ rrk: p.ResidentKeyNotRequired(),
  uv: "preferred",
  },
  p.AuthenticatorSelection{
  AuthenticatorAttachment: p.Platform,
- RequireResidentKey: p.ResidentKeyUnrequired(),
+ RequireResidentKey: p.ResidentKeyNotRequired(),
  UserVerification: p.VerificationPreferred,
  },
  },

webauthn/registration.go

@@ -113,6 +113,19 @@ func WithAppIdExcludeExtension(appid string) RegistrationOption {
  }
 }
 
+// WithResidentKeyRequirement sets both the resident key and require resident key protocol options. When
+func WithResidentKeyRequirement(requirement protocol.ResidentKeyRequirement) RegistrationOption {
+ return func(cco *protocol.PublicKeyCredentialCreationOptions) {
+ cco.AuthenticatorSelection.ResidentKey = requirement
+ switch requirement {
+ case protocol.ResidentKeyRequirementRequired:
+ cco.AuthenticatorSelection.RequireResidentKey = protocol.ResidentKeyRequired()
+ default:
+ cco.AuthenticatorSelection.RequireResidentKey = protocol.ResidentKeyNotRequired()
+ }
+ }
+}
+
 // Take the response from the authenticator and client and verify the credential against the user's credentials and
 // session data.
 func (webauthn *WebAuthn) FinishRegistration(user User, session SessionData, response *http.Request) (*Credential, error) {