fix(ctap2): feature-detect credProtect via getInfo extensions when enforcing policy

The enforcement gate keyed off is_uv_protected, which reports whether a PIN or built-in UV is configured rather than whether the authenticator implements credProtect. Detect the extension from the getInfo extensions array instead. This refuses authenticators that would silently drop an enforced policy and stops rejecting credProtect-capable authenticators that have no PIN or UV set yet.

Author: AlfioEmanueleFresta

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

@@ -237,7 +237,7 @@ impl Ctap2MakeCredentialsRequestExtensions {
         if let Some(cred_protection) = requested_extensions.cred_protect.as_ref() {
             if cred_protection.enforce_policy
                 && cred_protection.policy != CredentialProtectionPolicy::UserVerificationOptional
-                && !info.is_uv_protected()
+                && !info.supports_extension("credProtect")
             {
                 return Err(Error::Ctap(CtapError::UnsupportedExtension));
             }
@@ -498,7 +498,9 @@ pub struct Ctap2MakeCredentialsResponseExtensions {
 mod tests {
     use super::*;
     use crate::ops::webauthn::MakeCredentialLargeBlobExtensionInput;
-    use crate::ops::webauthn::{MakeCredentialPrfInput, MakeCredentialRequest};
+    use crate::ops::webauthn::{
+        CredentialProtectionExtension, MakeCredentialPrfInput, MakeCredentialRequest,
+    };
     use std::collections::HashMap;
     use std::time::Duration;
 
@@ -581,6 +583,78 @@ mod tests {
         assert_eq!(extensions.large_blob_key, None);
     }
 
+    fn requested_with_cred_protect(
+        policy: CredentialProtectionPolicy,
+        enforce_policy: bool,
+    ) -> MakeCredentialsRequestExtensions {
+        MakeCredentialsRequestExtensions {
+            cred_protect: Some(CredentialProtectionExtension {
+                policy,
+                enforce_policy,
+            }),
+            ..MakeCredentialsRequestExtensions::default()
+        }
+    }
+
+    #[test]
+    fn cred_protect_enforced_above_optional_without_support_returns_unsupported_extension() {
+        // UV-protected but credProtect not advertised: must fail, not silently drop the policy.
+        let info = info_with_options(&[("clientPin", true)]);
+        let requested =
+            requested_with_cred_protect(CredentialProtectionPolicy::UserVerificationRequired, true);
+        let result =
+            Ctap2MakeCredentialsRequestExtensions::from_webauthn_request(&requested, &info);
+        assert!(matches!(
+            result,
+            Err(Error::Ctap(CtapError::UnsupportedExtension))
+        ));
+    }
+
+    #[test]
+    fn cred_protect_enforced_above_optional_with_support_carries_policy() {
+        // credProtect advertised but no PIN/UV set yet: still honour the policy.
+        let info = info_with_extensions(&["credProtect"]);
+        let requested =
+            requested_with_cred_protect(CredentialProtectionPolicy::UserVerificationRequired, true);
+        let extensions =
+            Ctap2MakeCredentialsRequestExtensions::from_webauthn_request(&requested, &info)
+                .unwrap();
+        assert_eq!(
+            extensions.cred_protect,
+            Some(Ctap2CredentialProtectionPolicy::Required)
+        );
+    }
+
+    #[test]
+    fn cred_protect_enforced_optional_is_never_rejected() {
+        let info = Ctap2GetInfoResponse::default();
+        let requested =
+            requested_with_cred_protect(CredentialProtectionPolicy::UserVerificationOptional, true);
+        let extensions =
+            Ctap2MakeCredentialsRequestExtensions::from_webauthn_request(&requested, &info)
+                .unwrap();
+        assert_eq!(
+            extensions.cred_protect,
+            Some(Ctap2CredentialProtectionPolicy::Optional)
+        );
+    }
+
+    #[test]
+    fn cred_protect_not_enforced_above_optional_is_never_rejected() {
+        let info = Ctap2GetInfoResponse::default();
+        let requested = requested_with_cred_protect(
+            CredentialProtectionPolicy::UserVerificationRequired,
+            false,
+        );
+        let extensions =
+            Ctap2MakeCredentialsRequestExtensions::from_webauthn_request(&requested, &info)
+                .unwrap();
+        assert_eq!(
+            extensions.cred_protect,
+            Some(Ctap2CredentialProtectionPolicy::Required)
+        );
+    }
+
     fn info_with_extensions(exts: &[&str]) -> Ctap2GetInfoResponse {
         Ctap2GetInfoResponse {
             extensions: Some(exts.iter().map(|s| s.to_string()).collect()),