Ensure key generation retries after remote key provisioning

Previously, the key pair generation would error out even if we
successfully provisioned attestation keys. Instead, we should retry
key generation after the GenerateRkpKeyService reports an OK status.

Bug: 231495834
Test: RemoteProvisionerUnitTests
Change-Id: I049294cbc7119de55b5de02499bf4609d4c6de5d

1 files changed, 8 insertions, 5 deletions

diff --git a/keystore/java/android/security/keystore2/AndroidKeyStoreKeyPairGeneratorSpi.java b/keystore/java/android/security/keystore2/AndroidKeyStoreKeyPairGeneratorSpi.java
index 40659f5dbfb0..cdc1085a5015 100644
--- a/keystore/java/android/security/keystore2/AndroidKeyStoreKeyPairGeneratorSpi.java
+++ b/keystore/java/android/security/keystore2/AndroidKeyStoreKeyPairGeneratorSpi.java
@@ -712,7 +712,7 @@ public abstract class AndroidKeyStoreKeyPairGeneratorSpi extends KeyPairGenerato
                 case KeymasterDefs.KM_ERROR_HARDWARE_TYPE_UNAVAILABLE:
                     throw new StrongBoxUnavailableException("Failed to generated key pair.", e);
                 case ResponseCode.OUT_OF_KEYS:
-                    throw makeOutOfKeysException(e, securityLevel);
+                    return checkIfRetryableOrThrow(e, securityLevel);
                 default:
                     ProviderException p = new ProviderException("Failed to generate key pair.", e);
                     if ((mSpec.getPurposes() & KeyProperties.PURPOSE_WRAP_KEY) != 0) {
@@ -740,7 +740,7 @@ public abstract class AndroidKeyStoreKeyPairGeneratorSpi extends KeyPairGenerato
 
     // In case keystore reports OUT_OF_KEYS, call this handler in an attempt to remotely provision
     // some keys.
-    private ProviderException makeOutOfKeysException(KeyStoreException e, int securityLevel) {
+    GenerateKeyPairHelperResult checkIfRetryableOrThrow(KeyStoreException e, int securityLevel) {
         GenerateRkpKey keyGen = new GenerateRkpKey(ActivityThread
                 .currentApplication());
         KeyStoreException ksException;
@@ -757,8 +757,11 @@ public abstract class AndroidKeyStoreKeyPairGeneratorSpi extends KeyPairGenerato
                     rkpStatus = KeyStoreException.RKP_SERVER_REFUSED_ISSUANCE;
                     break;
                 case IGenerateRkpKeyService.Status.OK:
-                    // This will actually retry once immediately, so on "OK" go ahead and return
-                    // "temporarily unavailable". @see generateKeyPair
+                    // Explicitly return not-OK here so we retry in generateKeyPair. All other cases
+                    // should throw because a retry doesn't make sense if we didn't actually
+                    // provision fresh keys.
+                    return new GenerateKeyPairHelperResult(
+                            KeyStoreException.RKP_TEMPORARILY_UNAVAILABLE, null);
                 case IGenerateRkpKeyService.Status.NETWORK_COMMUNICATION_ERROR:
                 case IGenerateRkpKeyService.Status.HTTP_CLIENT_ERROR:
                 case IGenerateRkpKeyService.Status.HTTP_SERVER_ERROR:
@@ -781,7 +784,7 @@ public abstract class AndroidKeyStoreKeyPairGeneratorSpi extends KeyPairGenerato
                     KeyStoreException.RKP_TEMPORARILY_UNAVAILABLE);
         }
         ksException.initCause(e);
-        return new ProviderException("Failed to talk to RemoteProvisioner", ksException);
+        throw new ProviderException("Failed to provision new attestation keys.", ksException);
     }
 
     private void addAttestationParameters(@NonNull List<KeyParameter> params)