From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nikolay Aleksandrov Subject: Re: [PATCH net-next 0/3] ipmr/ip6mr: add Netlink notifications on cache reports Date: Thu, 15 Jun 2017 14:44:40 +0300 Message-ID: <01588135-b3d6-bc92-be31-0ae86310d904@cumulusnetworks.com> References: <20170613170822.16310-1-julien@arista.com> <891d876f-18fb-706b-c269-ec8892d2f6ff@cumulusnetworks.com> <7b133850-bbdc-594c-f7f3-62e9d4adf1f3@arista.com> <2d412677-d31a-7740-952c-b1b007bbf075@cumulusnetworks.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: Netdev , Donald Sharp To: Julien Gomes , davem@davemloft.net Return-path: Received: from mail-lf0-f51.google.com ([209.85.215.51]:34033 "EHLO mail-lf0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751972AbdFOLon (ORCPT ); Thu, 15 Jun 2017 07:44:43 -0400 Received: by mail-lf0-f51.google.com with SMTP id v20so7489766lfa.1 for ; Thu, 15 Jun 2017 04:44:42 -0700 (PDT) In-Reply-To: <2d412677-d31a-7740-952c-b1b007bbf075@cumulusnetworks.com> Sender: netdev-owner@vger.kernel.org List-ID: On 15/06/17 14:33, Nikolay Aleksandrov wrote: > On 15/06/17 00:51, Julien Gomes wrote: >> Hi Nikolay, >> >> On 06/14/2017 05:04 AM, Nikolay Aleksandrov wrote: >> >>> This has been on our todo list and I'm definitely interested in the implementation. >>> A few things that need careful consideration from my POV. First are the security >>> implications - this sends rtnl multicast messages but the rtnl socket has >>> the NL_CFG_F_NONROOT_RECV flag thus allowing any user on the system to listen in. >>> This would allow them to see the full packets and all reports (granted they can see >>> the notifications even now), but the full packet is like giving them the opportunity >>> to tcpdump the PIM traffic. >> >> I definitely see how this can be an issue. >> From what I see, this means that either the packet should be >> transmitted another way, or another Netlink family should be used. >> >> NETLINK_ROUTE looks to be the logical family to choose though, >> but then I do not see a proper other way to handle this. > > Right, currently me neither, unless it provides a bind callback when registering > the kernel socket. > >> >> However I may just not be looking into the right direction, >> maybe you currently have another approach in mind? > > I haven't gotten around to make (or even try) them but I was thinking about 2 options > ending up with a similar result: > > 1) genetlink > It also has the NONROOT_RECV flag, but it also allows for a callback - mcast_bind() > which can be used to filter. > > or > > 2) Providing a bind callback to the NETLINK_ROUTE socket. > Ah nevermind, these cannot be used for filtering currently, so it seems the netlink interface would need to be extended too if going down this road. > I haven't checked in detail how feasible each option is. To me 2) seems like the > cleaner/proper way to do it but it requires extending the rtnetlink api. > > It would be nice to get feedback and comments from more people on this. > >> >>> My second (more fixable and minor) concern is about the packet itself, how do you >>> know that the packet is all linear so you can directly copy it ? >> >> Indeed, I overlooked this possibility in this version. >> I will improve that. >> > > Thanks! >