From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pablo Neira Ayuso Subject: Re: [PATCH nf-next 3/3] netfilter: nft_log: fix snaplen does not truncate packets Date: Wed, 20 Jul 2016 10:25:21 +0200 Message-ID: <20160720082521.GA1336@salvia> References: <1468845857-30291-1-git-send-email-zlpnobody@163.com> <1468845857-30291-4-git-send-email-zlpnobody@163.com> <20160719181600.GD6116@salvia> <60a932e7.d60.15605635cca.Coremail.zlpnobody@163.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netfilter-devel@vger.kernel.org, Liping Zhang To: Liping Zhang Return-path: Received: from mail.us.es ([193.147.175.20]:50936 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752730AbcGTIZg (ORCPT ); Wed, 20 Jul 2016 04:25:36 -0400 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id 570BD114804 for ; Wed, 20 Jul 2016 10:25:34 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 46EFAFAB5A for ; Wed, 20 Jul 2016 10:25:34 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id A174AFAB5F for ; Wed, 20 Jul 2016 10:25:30 +0200 (CEST) Content-Disposition: inline In-Reply-To: <60a932e7.d60.15605635cca.Coremail.zlpnobody@163.com> Sender: netfilter-devel-owner@vger.kernel.org List-ID: On Wed, Jul 20, 2016 at 07:00:13AM +0800, Liping Zhang wrote: > At 2016-07-20 02:16:00, "Pablo Neira Ayuso" wrote: > >On Mon, Jul 18, 2016 at 08:44:17PM +0800, Liping Zhang wrote: > >> From: Liping Zhang > >> > >> There's a similar problem in xt_NFLOG, and was fixed by commit 7643507fe8b5 > >> ("netfilter: xt_NFLOG: nflog-range does not truncate packets"). Only set > >> copy_len here does not work, so we should enable NF_LOG_F_COPY_LEN also. > > > >Applied, thanks. > > > >Will you send me a patch for nftables userspace to enable this flag? > > > >It would be good to update the translation to make sure --nflog-size > >map to snaplen and ignore --nflog-range. > > I find that nftables already support this feature, the following command mean to truncate packets > to 100 bytes before logging to the userspace: > #nft add rule filter input log group 0 snaplen 100 > > Before my patch, it does not work. > And after apply my patch, it works as expected. If I git grep NF_LOG_F_COPY_LEN from the nftables.git tree, I don't see any reference to this flag being set. Then, nft_log kernel has been actually working fine since the beginning. It would be good anyway if we set this flag on from userspace to leave things in consistent state.