From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 175B5C433FE for ; Tue, 2 Nov 2021 01:57:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EB87C60F56 for ; Tue, 2 Nov 2021 01:57:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230322AbhKBCAM (ORCPT ); Mon, 1 Nov 2021 22:00:12 -0400 Received: from pi.codeconstruct.com.au ([203.29.241.158]:44532 "EHLO codeconstruct.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229486AbhKBCAL (ORCPT ); Mon, 1 Nov 2021 22:00:11 -0400 Received: from pecola.lan (unknown [159.196.93.152]) by mail.codeconstruct.com.au (Postfix) with ESMTPSA id C2B7320164; Tue, 2 Nov 2021 09:57:34 +0800 (AWST) Message-ID: Subject: Re: [PATCH net-next 0/2] MCTP sockaddr padding check/initialisation fixup From: Jeremy Kerr To: Eugene Syromiatnikov , Matt Johnston Cc: "David S. Miller" , Jakub Kicinski , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Date: Tue, 02 Nov 2021 09:57:34 +0800 In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.38.3-1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Eugene, > Padding/reserved fields necessitate appropriate checks in order to be > usable in the future. We don't have a foreseeable need for extra fields here; so this is a bit hypothetical at the moment. However, I guess there may be something that comes up in future - was there something you have in mind? The requirements for the padding bytes to be zero on sendmsg() will break the ABI for applications that are using the interface on 5.15; there's a small, contained set of those at the moment though, so I'm OK to handle the updates if this patch is accepted, but we'd need to make a call on that soon. Setting the pad bytes to zero on recvmsg() is a good plan though, I'm happy for that change to go in regardless. Cheers, Jeremy