Refactor decodeAuthenticatorExtensions

1 files changed, 26 insertions, 5 deletions

diff --git a/packages/server/src/helpers/decodeAuthenticatorExtensions.ts b/packages/server/src/helpers/decodeAuthenticatorExtensions.ts
index b34fdc3..e6d0781 100644
--- a/packages/server/src/helpers/decodeAuthenticatorExtensions.ts
+++ b/packages/server/src/helpers/decodeAuthenticatorExtensions.ts
@@ -1,4 +1,4 @@
-import { decodeCborFirst } from './decodeCbor';
+import * as cbor from './cbor';
 
 /**
  * Convert authenticator extension data buffer to a proper object
@@ -8,14 +8,15 @@ import { decodeCborFirst } from './decodeCbor';
 export function decodeAuthenticatorExtensions(
   extensionData: Uint8Array,
 ): AuthenticationExtensionsAuthenticatorOutputs | undefined {
-  let toCBOR: AuthenticationExtensionsAuthenticatorOutputs | undefined;
+  let toCBOR: Map<string, unknown>;
   try {
-    toCBOR = decodeCborFirst(extensionData);
+    toCBOR = cbor.decodeFirst(extensionData);
   } catch (err) {
     const _err = err as Error;
     throw new Error(`Error decoding authenticator extensions: ${_err.message}`);
   }
-  return toCBOR;
+
+  return convertMapToObjectDeep(toCBOR);
 }
 
 export type AuthenticationExtensionsAuthenticatorOutputs = {
@@ -25,8 +26,9 @@ export type AuthenticationExtensionsAuthenticatorOutputs = {
 
 export type DevicePublicKeyAuthenticatorOutput = {
   dpk?: Uint8Array;
-  scp?: Uint8Array;
   sig?: string;
+  nonce?: Uint8Array;
+  scope?: Uint8Array;
   aaguid?: Uint8Array;
 };
 
@@ -35,3 +37,22 @@ export type DevicePublicKeyAuthenticatorOutput = {
 export type UVMAuthenticatorOutput = {
   uvm?: Uint8Array[];
 };
+
+/**
+ * CBOR-encoded extensions can be deeply-nested Maps, which are too deep for a simple
+ * `Object.entries()`. This method will recursively make sure that all Maps are converted into
+ * basic objects.
+ */
+function convertMapToObjectDeep(input: Map<string, unknown>): { [key: string]: unknown } {
+  const mapped: { [key: string]: unknown } = {};
+
+  for (const [key, value] of input) {
+    if (value instanceof Map) {
+      mapped[key] = convertMapToObjectDeep(value);
+    } else {
+      mapped[key] = value;
+    }
+  }
+
+  return mapped;
+}