diff --git a/sys/nfs41_driver.c b/sys/nfs41_driver.c
index eb930cf..e8d2d47 100644
--- a/sys/nfs41_driver.c
+++ b/sys/nfs41_driver.c
@@ -4787,7 +4787,8 @@ NTSTATUS check_nfs41_getacl_args(
         status = STATUS_NOT_SUPPORTED;
         goto out;
     }
-    if (RxContext->CurrentIrp->UserBuffer == NULL)
+    if (RxContext->CurrentIrp->UserBuffer == NULL &&
+            RxContext->CurrentIrpSp->Parameters.QuerySecurity.Length)
         status = STATUS_INVALID_USER_BUFFER;
 out:
     return status;
@@ -4931,7 +4932,8 @@ NTSTATUS check_nfs41_setacl_args(
         status = STATUS_NOT_SUPPORTED;       
         goto out;
     }
-    if (RxContext->CurrentIrp->UserBuffer == NULL)
+    if (RxContext->CurrentIrp->UserBuffer == NULL && 
+            RxContext->CurrentIrpSp->Parameters.QuerySecurity.Length)
         status = STATUS_INVALID_USER_BUFFER;    
 out:
     return status;