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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 77B97C433DF for ; Thu, 9 Jul 2020 19:36:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4981820672 for ; Thu, 9 Jul 2020 19:36:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726664AbgGITg1 (ORCPT ); Thu, 9 Jul 2020 15:36:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38004 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726213AbgGITg1 (ORCPT ); Thu, 9 Jul 2020 15:36:27 -0400 Received: from shards.monkeyblade.net (shards.monkeyblade.net [IPv6:2620:137:e000::1:9]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 800EEC08C5CE; Thu, 9 Jul 2020 12:36:27 -0700 (PDT) Received: from localhost (unknown [IPv6:2601:601:9f00:477::3d5]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 3B92112794C20; Thu, 9 Jul 2020 12:36:27 -0700 (PDT) Date: Thu, 09 Jul 2020 12:36:26 -0700 (PDT) Message-Id: <20200709.123626.261284515556787924.davem@davemloft.net> To: mkubecek@suse.cz Cc: kuba@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net] ethtool: fix genlmsg_put() failure handling in ethnl_default_dumpit() From: David Miller In-Reply-To: <20200709101150.65DBB60567@lion.mk-sys.cz> References: <20200709101150.65DBB60567@lion.mk-sys.cz> X-Mailer: Mew version 6.8 on Emacs 26.3 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Thu, 09 Jul 2020 12:36:27 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Michal Kubecek Date: Thu, 9 Jul 2020 12:11:50 +0200 (CEST) > If the genlmsg_put() call in ethnl_default_dumpit() fails, we bail out > without checking if we already have some messages in current skb like we do > with ethnl_default_dump_one() failure later. Therefore if existing messages > almost fill up the buffer so that there is not enough space even for > netlink and genetlink header, we lose all prepared messages and return and > error. > > Rather than duplicating the skb->len check, move the genlmsg_put(), > genlmsg_cancel() and genlmsg_end() calls into ethnl_default_dump_one(). > This is also more logical as all message composition will be in > ethnl_default_dump_one() and only iteration logic will be left in > ethnl_default_dumpit(). > > Fixes: 728480f12442 ("ethtool: default handlers for GET requests") > Reported-by: Jakub Kicinski > Signed-off-by: Michal Kubecek Applied and queued up for -stable, thanks.