Add permission check on onKeyguardVisibilityChanged

Without this permission check any app can toggle the locked state of
keymaster once it has been unlocked for the first time.

Bug: 144285084
Test: Manually tested with debugger that the requred code paths are
      run.

Merged-In: Idb8a200dc2963e1085e9fddd0c565c5172465e65
Change-Id: Idb8a200dc2963e1085e9fddd0c565c5172465e65
(cherry picked from commit 21f452c3722ad7fa39c7d84c4723bcbb723ab164)

1 files changed, 15 insertions, 4 deletions

diff --git a/keystore/key_store_service.cpp b/keystore/key_store_service.cpp
index 2336e570..b6b72952 100644
--- a/keystore/key_store_service.cpp
+++ b/keystore/key_store_service.cpp
@@ -1359,12 +1359,23 @@ bool KeyStoreService::checkAllowedOperationParams(const hidl_vec<KeyParameter>&
 }
 
 Status KeyStoreService::onKeyguardVisibilityChanged(bool isShowing, int32_t userId,
-                                                    int32_t* aidl_return) {
+                                                    int32_t* _aidl_return) {
     KEYSTORE_SERVICE_LOCK;
+    if (isShowing) {
+        if (!checkBinderPermission(P_LOCK, UID_SELF)) {
+            LOG(WARNING) << "onKeyguardVisibilityChanged called with isShowing == true but "
+                            "without LOCK permission";
+            return AIDL_RETURN(ResponseCode::PERMISSION_DENIED);
+        }
+    } else {
+        if (!checkBinderPermission(P_UNLOCK, UID_SELF)) {
+            LOG(WARNING) << "onKeyguardVisibilityChanged called with isShowing == false but "
+                            "without UNLOCK permission";
+            return AIDL_RETURN(ResponseCode::PERMISSION_DENIED);
+        }
+    }
     mKeyStore->getEnforcementPolicy().set_device_locked(isShowing, userId);
-    *aidl_return = static_cast<int32_t>(ResponseCode::NO_ERROR);
-
-    return Status::ok();
+    return AIDL_RETURN(ResponseCode::NO_ERROR);
 }
 
 }  // namespace keystore