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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_NEOMUTT autolearn=ham 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 154E3ECDE5F for ; Mon, 23 Jul 2018 10:52:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C1D3420875 for ; Mon, 23 Jul 2018 10:52:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C1D3420875 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=strlen.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387941AbeGWLwp (ORCPT ); Mon, 23 Jul 2018 07:52:45 -0400 Received: from Chamillionaire.breakpoint.cc ([146.0.238.67]:35468 "EHLO Chamillionaire.breakpoint.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387815AbeGWLwp (ORCPT ); Mon, 23 Jul 2018 07:52:45 -0400 Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.89) (envelope-from ) id 1fhYRb-0008Ja-Tm; Mon, 23 Jul 2018 12:52:00 +0200 Date: Mon, 23 Jul 2018 12:51:59 +0200 From: Florian Westphal To: Pablo Neira Ayuso Cc: Florian Westphal , David Miller , cscnull@gmail.com, kadlec@blackhole.kfki.hu, johannes.berg@intel.com, Jason@zx2c4.com, ktkhai@virtuozzo.com, lucien.xin@gmail.com, xiyou.wangcong@gmail.com, dsahern@gmail.com, netfilter-devel@vger.kernel.org, tom@quantonium.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] netlink: fix memory leak of dump Message-ID: <20180723105159.vpknxgam3fqeicvv@breakpoint.cc> References: <20180722143354.23722-1-cscnull@gmail.com> <20180722163925.gdfkndldatsoae6x@breakpoint.cc> <20180722.100755.19840167505550163.davem@davemloft.net> <20180722180910.wcwhantwpm2nfxet@breakpoint.cc> <20180723091551.mwhltw4ujm4bylvj@salvia> <20180723092818.ztsfsnqzxgzrauim@breakpoint.cc> <20180723093855.c4ncixsnkee6r34v@salvia> <20180723094228.mejwuvoyitolqktv@breakpoint.cc> <20180723094742.gg6e73l6aknghal7@salvia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180723094742.gg6e73l6aknghal7@salvia> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Pablo Neira Ayuso wrote: > On Mon, Jul 23, 2018 at 11:42:28AM +0200, Florian Westphal wrote: > We can also add another scratchpad area, similar to the ->cb[x] area > that can be initialized before netlink_dump_start()? So we don't need > the data pointer. > > By passing the array of attributes, we'll need to do attribute parsing > over and over again from each netlink_dump() call. Its still done once, parsing is only delayed/moved to ->start(). Now: nla_parse control->data = kmalloc() + init netlink_dump_start() ->start() /* if it returns 0, done() will be called eventually netlink_dump() ->done() free(cb->data); Proposed fix: control->data = &on_stack; netlink_dump_start() ->start() nla_parse cb->data = kmalloc() + init netlink_dump() ->done() free(cb->data); I've submitted a patch for nf_tables, let me know if you have a better idea or see a problem with it.