chore(api): mark growable public response and spec types non_exhaustive

Add #[non_exhaustive] to CTAP2 command, transport, attestation and
biometric enums plus the get-info, make-credential, get-assertion,
bio-enrollment, credential-management, client-pin and large-blobs
response structs so adding fields or variants stays backward
compatible. Seal the test-only dummy() constructors out of the public
API.

Author: AlfioEmanueleFresta

libwebauthn/src/ops/webauthn/make_credential.rs

@@ -652,7 +652,8 @@ pub struct MakeCredentialsRequestExtensions {
 pub type MakeCredentialsResponseExtensions = Ctap2MakeCredentialsResponseExtensions;
 
 impl MakeCredentialRequest {
-    pub fn dummy() -> Self {
+    #[cfg(test)]
+    pub(crate) fn dummy() -> Self {
         Self {
             challenge: Vec::new(),
             origin: "example.org".to_owned(),

libwebauthn/src/proto/ctap1/model.rs

@@ -86,7 +86,7 @@ impl Ctap1RegisterRequest {
         }
     }
 
-    pub fn dummy(timeout: Duration) -> Self {
+    pub(crate) fn dummy(timeout: Duration) -> Self {
         Ctap1RegisterRequest {
             version: Ctap1Version::U2fV2,
             app_id_hash: vec![0; 32],

libwebauthn/src/proto/ctap2/model.rs

@@ -50,8 +50,29 @@ pub use credential_management::{
 mod large_blobs;
 pub use large_blobs::{Ctap2LargeBlobsRequest, Ctap2LargeBlobsResponse};
 
+/// CTAP2 command codes; `#[non_exhaustive]` so consumers handle unknown variants.
+///
+/// ```compile_fail
+/// use libwebauthn::proto::ctap2::Ctap2CommandCode;
+/// let code = Ctap2CommandCode::AuthenticatorGetInfo;
+/// let _value: u8 = match code {
+///     Ctap2CommandCode::AuthenticatorMakeCredential => 0x01,
+///     Ctap2CommandCode::AuthenticatorGetAssertion => 0x02,
+///     Ctap2CommandCode::AuthenticatorGetInfo => 0x04,
+///     Ctap2CommandCode::AuthenticatorClientPin => 0x06,
+///     Ctap2CommandCode::AuthenticatorGetNextAssertion => 0x08,
+///     Ctap2CommandCode::AuthenticatorBioEnrollment => 0x09,
+///     Ctap2CommandCode::AuthenticatorBioEnrollmentPreview => 0x40,
+///     Ctap2CommandCode::AuthenticatorCredentialManagement => 0x0A,
+///     Ctap2CommandCode::AuthenticatorCredentialManagementPreview => 0x41,
+///     Ctap2CommandCode::AuthenticatorSelection => 0x0B,
+///     Ctap2CommandCode::AuthenticatorLargeBlobs => 0x0C,
+///     Ctap2CommandCode::AuthenticatorConfig => 0x0D,
+/// };
+/// ```
 #[derive(Debug, IntoPrimitive, TryFromPrimitive, Copy, Clone, PartialEq, Serialize_repr)]
 #[repr(u8)]
+#[non_exhaustive]
 pub enum Ctap2CommandCode {
     AuthenticatorMakeCredential = 0x01,
     AuthenticatorGetAssertion = 0x02,
@@ -78,7 +99,7 @@ pub struct Ctap2PublicKeyCredentialRpEntity {
 }
 
 impl Ctap2PublicKeyCredentialRpEntity {
-    pub fn dummy() -> Self {
+    pub(crate) fn dummy() -> Self {
         Self {
             id: String::from(".dummy"),
             name: Some(String::from(".dummy")),
@@ -109,7 +130,7 @@ pub struct Ctap2PublicKeyCredentialUserEntity {
 }
 
 impl Ctap2PublicKeyCredentialUserEntity {
-    pub fn dummy() -> Self {
+    pub(crate) fn dummy() -> Self {
         Self {
             id: ByteBuf::from([1]),
             name: Some(String::from("dummy")),
@@ -150,6 +171,7 @@ pub enum Ctap2PublicKeyCredentialType {
 /// AuthenticatorTransport from a credential descriptor. Unknown values are kept in `Other` so they pass through unchanged.
 #[derive(Debug, Clone, PartialEq, Eq, Hash, Serialize, Deserialize)]
 #[serde(from = "String", into = "String")]
+#[non_exhaustive]
 pub enum Ctap2Transport {
     Ble,
     Nfc,

libwebauthn/src/proto/ctap2/model/bio_enrollment.rs

@@ -68,6 +68,7 @@ pub struct Ctap2BioEnrollmentParams {
 }
 
 #[derive(Debug, Default, Clone, DeserializeIndexed)]
+#[non_exhaustive]
 pub struct Ctap2BioEnrollmentResponse {
     // modality (0x01) 	Unsigned Integer 	Optional 	The user verification modality.
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -145,12 +146,14 @@ pub enum Ctap2LastEnrollmentSampleStatus {
 
 #[repr(u64)]
 #[derive(Debug, Clone, FromPrimitive, PartialEq, Serialize_repr, Deserialize_repr)]
+#[non_exhaustive]
 pub enum Ctap2BioEnrollmentModality {
     Fingerprint = 0x01, // Fingerprint was too high.
 }
 
 #[repr(u64)]
 #[derive(Debug, Clone, FromPrimitive, PartialEq, Serialize_repr, Deserialize_repr)]
+#[non_exhaustive]
 pub enum Ctap2BioEnrollmentFingerprintKind {
     Touch = 0x01,
     Swipe = 0x02,

libwebauthn/src/proto/ctap2/model/client_pin.rs

@@ -224,6 +224,7 @@ pub enum Ctap2PinUvAuthProtocolCommand {
 
 #[cfg_attr(test, derive(SerializeIndexed))]
 #[derive(Debug, Clone, Default, DeserializeIndexed)]
+#[non_exhaustive]
 pub struct Ctap2ClientPinResponse {
     /// keyAgreement (0x01)
     #[serde(skip_serializing_if = "Option::is_none")]

libwebauthn/src/proto/ctap2/model/credential_management.rs

@@ -89,6 +89,7 @@ pub struct Ctap2CredentialManagementParams {
 }
 
 #[derive(Debug, Default, Clone, DeserializeIndexed)]
+#[non_exhaustive]
 pub struct Ctap2CredentialManagementResponse {
     // existingResidentCredentialsCount (0x01) 	Unsigned Integer 	Number of existing discoverable credentials present on the authenticator.
     #[serde(skip_serializing_if = "Option::is_none")]

libwebauthn/src/proto/ctap2/model/get_assertion.rs

@@ -92,6 +92,7 @@ pub struct AppleAnonymousAttestationStmt {
 
 #[derive(Debug, Clone, Deserialize, Serialize)]
 #[serde(untagged)]
+#[non_exhaustive]
 pub enum Ctap2AttestationStatement {
     PackedOrAndroid(PackedAttestationStmt),
     Tpm(TpmAttestationStmt),
@@ -512,6 +513,7 @@ pub struct CalculatedHMACGetSecretInput {
 }
 
 #[derive(Debug, Clone, DeserializeIndexed)]
+#[non_exhaustive]
 pub struct Ctap2GetAssertionResponse {
     #[serde(skip_serializing_if = "Option::is_none")]
     #[serde(index = 0x01)]
@@ -687,6 +689,7 @@ impl Ctap2GetAssertionResponse {
 
 #[derive(Debug, Default, Clone, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
+#[non_exhaustive]
 pub struct Ctap2GetAssertionResponseExtensions {
     // Stored credBlob
     #[serde(default, skip_serializing_if = "Option::is_none", with = "serde_bytes")]

libwebauthn/src/proto/ctap2/model/get_info.rs

@@ -10,6 +10,7 @@ use super::{Ctap2CredentialType, Ctap2UserVerificationOperation};
 
 #[cfg_attr(test, derive(SerializeIndexed))]
 #[derive(Debug, Clone, DeserializeIndexed, Default)]
+#[non_exhaustive]
 pub struct Ctap2GetInfoResponse {
     /// versions (0x01)
     #[serde(index = 0x01)]

libwebauthn/src/proto/ctap2/model/large_blobs.rs

@@ -88,6 +88,7 @@ impl Ctap2LargeBlobsRequest {
 
 #[cfg_attr(test, derive(SerializeIndexed))]
 #[derive(Debug, Default, Clone, DeserializeIndexed)]
+#[non_exhaustive]
 pub struct Ctap2LargeBlobsResponse {
     #[serde(skip_serializing_if = "Option::is_none")]
     #[serde(index = 0x01)]

libwebauthn/src/proto/ctap2/model/make_credential.rs

@@ -357,6 +357,7 @@ impl Ctap2MakeCredentialsRequestExtensions {
 }
 
 #[derive(Debug, Clone, DeserializeIndexed)]
+#[non_exhaustive]
 pub struct Ctap2MakeCredentialResponse {
     #[serde(index = 0x01)]
     pub format: String,
@@ -469,6 +470,7 @@ impl Ctap2UserVerifiableRequest for Ctap2MakeCredentialRequest {
 
 #[derive(Debug, Default, Clone, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
+#[non_exhaustive]
 pub struct Ctap2MakeCredentialsResponseExtensions {
     // If storing credBlob was successful
     #[serde(default, skip_serializing_if = "Option::is_none")]