Add isConfirmationPromptSupported() method.

This will be used by the android.security.ConfirmationDialog.isSupported() and
is intended so that apps can know ahead of time whether the device implements
the ConfirmationUI HAL.

Bug: 63928580
Test: Manually tested.
Change-Id: I6347824b4e2330a93b7a7ffd7cf5b206009a564e

5 files changed, 22 insertions, 0 deletions

diff --git a/keystore/binder/android/security/IKeystoreService.aidl b/keystore/binder/android/security/IKeystoreService.aidl
index 738eb686..1c8f9266 100644
--- a/keystore/binder/android/security/IKeystoreService.aidl
+++ b/keystore/binder/android/security/IKeystoreService.aidl
@@ -84,4 +84,5 @@ interface IKeystoreService {
     int presentConfirmationPrompt(IBinder listener, String promptText, in byte[] extraData,
         in String locale, in int uiOptionsAsFlags);
     int cancelConfirmationPrompt(IBinder listener);
+    boolean isConfirmationPromptSupported();
 }
diff --git a/keystore/confirmation_manager.cpp b/keystore/confirmation_manager.cpp
index d8c53784..acca3045 100644
--- a/keystore/confirmation_manager.cpp
+++ b/keystore/confirmation_manager.cpp
@@ -115,6 +115,19 @@ Status ConfirmationManager::cancelConfirmationPrompt(const sp<IBinder>& listener
     return Status::ok();
 }
 
+// Called by keystore main thread.
+Status ConfirmationManager::isConfirmationPromptSupported(bool* aidl_return) {
+    sp<IConfirmationUI> confirmationUI = IConfirmationUI::tryGetService();
+    if (confirmationUI == nullptr) {
+        ALOGW("Error getting confirmationUI service\n");
+        *aidl_return = false;
+        return Status::ok();
+    }
+
+    *aidl_return = true;
+    return Status::ok();
+}
+
 void ConfirmationManager::finalizeTransaction(ConfirmationResponseCode responseCode,
                                               hidl_vec<uint8_t> dataThatWasConfirmed,
                                               bool callAbortOnHal) {
diff --git a/keystore/confirmation_manager.h b/keystore/confirmation_manager.h
index 4bf4b8d6..b92dedaf 100644
--- a/keystore/confirmation_manager.h
+++ b/keystore/confirmation_manager.h
@@ -61,6 +61,9 @@ class ConfirmationManager : public android::hardware::hidl_death_recipient,
     Status cancelConfirmationPrompt(const android::sp<android::IBinder>& listener,
                                     int32_t* aidl_return);
 
+    // Checks if the confirmationUI HAL is available.
+    Status isConfirmationPromptSupported(bool* aidl_return);
+
     // Gets the latest confirmation token received from the ConfirmationUI HAL.
     hidl_vec<uint8_t> getLatestConfirmationToken();
 
diff --git a/keystore/key_store_service.cpp b/keystore/key_store_service.cpp
index d59966f4..d808c57f 100644
--- a/keystore/key_store_service.cpp
+++ b/keystore/key_store_service.cpp
@@ -1787,6 +1787,10 @@ Status KeyStoreService::cancelConfirmationPrompt(const sp<IBinder>& listener,
     return mConfirmationManager->cancelConfirmationPrompt(listener, aidl_return);
 }
 
+Status KeyStoreService::isConfirmationPromptSupported(bool* aidl_return) {
+    return mConfirmationManager->isConfirmationPromptSupported(aidl_return);
+}
+
 /**
  * Prune the oldest pruneable operation.
  */
diff --git a/keystore/key_store_service.h b/keystore/key_store_service.h
index ce809f87..70a56ca3 100644
--- a/keystore/key_store_service.h
+++ b/keystore/key_store_service.h
@@ -175,6 +175,7 @@ class KeyStoreService : public android::security::BnKeystoreService,
     ::android::binder::Status
     cancelConfirmationPrompt(const ::android::sp<::android::IBinder>& listener,
                              int32_t* _aidl_return) override;
+    ::android::binder::Status isConfirmationPromptSupported(bool* _aidl_return) override;
 
   private:
     static const int32_t UID_SELF = -1;