diff --git a/dlls/ntdll/reg.c b/dlls/ntdll/reg.c
index 794f188a8d8..a3a8cc158ec 100644
--- a/dlls/ntdll/reg.c
+++ b/dlls/ntdll/reg.c
@@ -84,12 +84,18 @@ NTSTATUS WINAPI NtCreateKey( PHANDLE retkey, ACCESS_MASK access, const OBJECT_AT
  *
  *  See NtCreateKey.
  */
-NTSTATUS WINAPI RtlpNtCreateKey( PHANDLE retkey, ACCESS_MASK access, OBJECT_ATTRIBUTES *attr,
+NTSTATUS WINAPI RtlpNtCreateKey( PHANDLE retkey, ACCESS_MASK access, const OBJECT_ATTRIBUTES *attr,
                                  ULONG TitleIndex, const UNICODE_STRING *class, ULONG options,
                                  PULONG dispos )
 {
+    OBJECT_ATTRIBUTES oa;
+
     if (attr)
-        attr->Attributes &= ~(OBJ_PERMANENT|OBJ_EXCLUSIVE);
+    {
+        memcpy( &oa, attr, sizeof oa );
+        oa.Attributes &= ~(OBJ_PERMANENT|OBJ_EXCLUSIVE);
+        attr = &oa;
+    }
 
     return NtCreateKey(retkey, access, attr, 0, NULL, 0, dispos);
 }
diff --git a/include/winternl.h b/include/winternl.h
index 1c3d62177de..8285f856fc2 100644
--- a/include/winternl.h
+++ b/include/winternl.h
@@ -2064,6 +2064,7 @@ NTSTATUS  WINAPI RtlVerifyVersionInfo(const RTL_OSVERSIONINFOEXW*,DWORD,DWORDLON
 
 NTSTATUS  WINAPI RtlWalkHeap(HANDLE,PVOID);
 
+NTSTATUS  WINAPI RtlpNtCreateKey(PHANDLE,ACCESS_MASK,const OBJECT_ATTRIBUTES*,ULONG,const UNICODE_STRING*,ULONG,PULONG);
 NTSTATUS  WINAPI RtlpWaitForCriticalSection(RTL_CRITICAL_SECTION *);
 NTSTATUS  WINAPI RtlpUnWaitCriticalSection(RTL_CRITICAL_SECTION *);