Make userHandle response field optional

changelog.txt

@@ -7,6 +7,7 @@ vNext
 - [MINOR] Add Child Spans for Interactive Span (#2516)
 - [MINOR] For MSAL CPP flows, match exact claims when deleting AT with intersecting scopes (#2548)
 - [MINOR] Replace Deprecated Keystore API for Android 28+ (#2558)
+- [PATCH] Make userHandle response field optional (#2560)
 
 Version 18.2.2
 ----------

common/src/main/java/com/microsoft/identity/common/internal/fido/WebAuthnJsonUtil.kt

@@ -30,13 +30,18 @@ import com.microsoft.identity.common.java.constants.FidoConstants.Companion.WEBA
 import com.microsoft.identity.common.java.constants.FidoConstants.Companion.WEBAUTHN_RESPONSE_ID_JSON_KEY
 import com.microsoft.identity.common.java.constants.FidoConstants.Companion.WEBAUTHN_RESPONSE_SIGNATURE_JSON_KEY
 import com.microsoft.identity.common.java.constants.FidoConstants.Companion.WEBAUTHN_RESPONSE_USER_HANDLE_JSON_KEY
+import com.microsoft.identity.common.logging.Logger
+import org.json.JSONException
 import org.json.JSONObject
 
 /**
  * A utility class to help convert to and from strings in WebAuthn json format.
  */
 class WebAuthnJsonUtil {
-    companion object {
+        companion object {
+
+            private val TAG = WebAuthnJsonUtil::class.simpleName.toString()
+
         /**
          * Takes applicable parameters and creates a string representation of
          *  PublicKeyCredentialRequestOptionsJSON (https://w3c.github.io/webauthn/#dictdef-publickeycredentialrequestoptionsjson)
@@ -74,6 +79,7 @@ class WebAuthnJsonUtil {
          * @throws JSONException if a value is not present that should be.
          */
         fun extractAuthenticatorAssertionResponseJson(fullResponseJson : String): String {
+            val methodTag = "$TAG:extractAuthenticatorAssertionResponseJson"
             val fullResponseJsonObject = JSONObject(fullResponseJson);
             val authResponseJsonObject = fullResponseJsonObject
                 .getJSONObject(FidoConstants.WEBAUTHN_AUTHENTICATION_ASSERTION_RESPONSE_JSON_KEY)
@@ -87,8 +93,16 @@ class WebAuthnJsonUtil {
                 WEBAUTHN_RESPONSE_CLIENT_DATA_JSON_KEY))
             assertionResult.put(WEBAUTHN_RESPONSE_SIGNATURE_JSON_KEY, authResponseJsonObject.get(
                 WEBAUTHN_RESPONSE_SIGNATURE_JSON_KEY))
-            assertionResult.put(WEBAUTHN_RESPONSE_USER_HANDLE_JSON_KEY, authResponseJsonObject.get(
-                WEBAUTHN_RESPONSE_USER_HANDLE_JSON_KEY))
+            // UserHandle is optional if allowCredentials was provided in the request (username flow).
+            if (authResponseJsonObject.isNull(WEBAUTHN_RESPONSE_USER_HANDLE_JSON_KEY)) {
+                Logger.info(methodTag, "UserHandle not found in assertion response.")
+            } else {
+                assertionResult.put(
+                    WEBAUTHN_RESPONSE_USER_HANDLE_JSON_KEY, authResponseJsonObject.get(
+                        WEBAUTHN_RESPONSE_USER_HANDLE_JSON_KEY
+                    )
+                )
+            }
             return assertionResult.toString()
         }
 

common/src/test/java/com/microsoft/identity/common/internal/fido/WebAuthnJsonUtilTest.kt

@@ -67,10 +67,10 @@ class WebAuthnJsonUtilTest {
     val attestationObject = "o2NmbXRkbm9uZWdhdHRTdG10oGhhdXRoRGF0YViUj5r_fLFhV-qdmGEwiukwD5E_5ama9g0hzXgN8thcFGRdAAAAAAAAAAAAAAAAAAAAAAAAAAAAEChA3rcWXFH4p4VYumWuZ2WlAQIDJiABIVgg4RqZaJyaC24Pf4tT-8ONIZ5_Elddf3dNotGOx81jj3siWCAWXS6Lz70hvC2g8hwoLllOwlsbYatNkO2uYFO-eJID6A"
 
     val expectedAuthenticationAssertionResponseJsonAllFieldsFilled = """{"authenticatorData":"$authenticatorData","clientDataJSON":"$clientDataJSON","id":"$idAssertionResponse","signature":"$signature","userHandle":"$userHandle"}"""
-    val expectedAuthenticationAssertionResponseOnlyRequiredFields = """{"authenticatorData":"$authenticatorData","clientDataJSON":"$clientDataJSON","id":"$idAssertionResponse","signature":"$signature","userHandle":"$userHandle"}"""
+    val expectedAuthenticationAssertionResponseOnlyRequiredFields = """{"authenticatorData":"$authenticatorData","clientDataJSON":"$clientDataJSON","id":"$idAssertionResponse","signature":"$signature"}"""
 
     val demoAuthenticationResponseJsonAllFieldsFilled = """{"authenticatorAttachment":"$authenticatorAttachment","clientExtensionResults":{},"id":"KEDetxZcUfinhVi6Za5nZQ","rawId":"KEDetxZcUfinhVi6Za5nZQ","response":{"attestationObject":"$attestationObject","authenticatorData":"$authenticatorData","clientDataJSON":"$clientDataJSON","id":"$idAssertionResponse","signature":"$signature","userHandle":"$userHandle"},"type":"public-key"}"""
-    val demoAuthenticationResponseJsonOnlyRequiredFields = """{"clientExtensionResults":{},"id":"KEDetxZcUfinhVi6Za5nZQ","rawId":"KEDetxZcUfinhVi6Za5nZQ","response":{"attestationObject":null,"authenticatorData":"$authenticatorData","clientDataJSON":"$clientDataJSON","id":"$idAssertionResponse","signature":"$signature","userHandle":"$userHandle"},"type":"public-key"}"""
+    val demoAuthenticationResponseJsonOnlyRequiredFields = """{"clientExtensionResults":{},"id":"KEDetxZcUfinhVi6Za5nZQ","rawId":"KEDetxZcUfinhVi6Za5nZQ","response":{"attestationObject":null,"authenticatorData":"$authenticatorData","clientDataJSON":"$clientDataJSON","id":"$idAssertionResponse","signature":"$signature"},"type":"public-key"}"""
     val demoAuthenticationResponseJsonMissingSignature = """{"clientExtensionResults":{},"id":"KEDetxZcUfinhVi6Za5nZQ","rawId":"KEDetxZcUfinhVi6Za5nZQ","response":{"attestationObject":null,"authenticatorData":"$authenticatorData","clientDataJSON":"$clientDataJSON","id":"$idAssertionResponse","userHandle":"$userHandle"},"type":"public-key"}"""
 
     // Demo JWT from https://jwt.io/