From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net] net: netlink: filter particular protocols from analyzers Date: Thu, 05 Sep 2013 14:44:42 -0400 (EDT) Message-ID: <20130905.144442.2085221662776542385.davem@davemloft.net> References: <1378396127-8342-1-git-send-email-dborkman@redhat.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, dborkmann@redhat.com To: dborkman@redhat.com Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:38542 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756868Ab3IESoo (ORCPT ); Thu, 5 Sep 2013 14:44:44 -0400 In-Reply-To: <1378396127-8342-1-git-send-email-dborkman@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Daniel Borkmann Date: Thu, 5 Sep 2013 17:48:47 +0200 > From: Daniel Borkmann > > Fix finer-grained control and let only a whitelist of allowed netlink > protocols pass, in our case related to networking. If later on, other > subsystems decide they want to add their protocol as well to the list > of allowed protocols they shall simply add it. While at it, we also > need to tell what protocol is in use otherwise BPF_S_ANC_PROTOCOL can > not pick it up (as it's not filled out). > > Signed-off-by: Daniel Borkmann This takes away functionality that I'd be more interesting in using, namely being able to listen to all netlink protocols using one tap. Seriously, when I first saw this feature, that was the first way I'd imagine myself using it, as a tcpdump for netlink traffic, all of it. If I just want to hear all netlink traffic, don't make me be forced to know every single NETLINK_* protocol value and have to open that many sockets just to do so. It also makes it so that I can't listen to userlevel custom netlink protocols, another minus of filtering. At the very least, allow an sk_protocol of zero or similar to have this meaning of "everything". I'm not applying this patch, sorry.