From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Borkmann Subject: Re: [PATCH net-next v2 1/2] bpf: Allow CGROUP_SKB eBPF program to access sk_buff Date: Tue, 06 Jun 2017 22:27:15 +0200 Message-ID: <59371023.605@iogearbox.net> References: <59369A30.1060301@iogearbox.net> <5936DB06.5070601@iogearbox.net> <20170606.162602.345656836042086290.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: chenbofeng.kernel@gmail.com, netdev@vger.kernel.org, lorenzo@google.com, ast@fb.com To: David Miller , fengc@google.com Return-path: Received: from www62.your-server.de ([213.133.104.62]:36112 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751239AbdFFU1U (ORCPT ); Tue, 6 Jun 2017 16:27:20 -0400 In-Reply-To: <20170606.162602.345656836042086290.davem@davemloft.net> Sender: netdev-owner@vger.kernel.org List-ID: On 06/06/2017 10:26 PM, David Miller wrote: > From: Chenbo Feng > Date: Tue, 6 Jun 2017 13:24:11 -0700 > >> On Tue, Jun 6, 2017 at 9:40 AM, Daniel Borkmann >> wrote: >> >>> On 06/06/2017 02:04 PM, Daniel Borkmann wrote: >>> >>>> On 06/01/2017 03:15 AM, Chenbo Feng wrote: >>>> >>>>> From: Chenbo Feng >>>>> >>>>> This allows cgroup eBPF program to classify packet based on their >>>>> protocol or other detail information. Currently program need >>>>> CAP_NET_ADMIN privilege to attach a cgroup eBPF program, and A >>>>> process with CAP_NET_ADMIN can already see all packets on the system, >>>>> for example, by creating an iptables rules that causes the packet to >>>>> be passed to userspace via NFLOG. >>>>> >>>>> Signed-off-by: Chenbo Feng >>>>> >>>> >>>> Sorry, but I am puzzled what above change log has to do with the >>>> below diff?! Back then we decided not to add BPF_PROG_TYPE_CGROUP_SKB >>>> to may_access_skb(), since one can already use bpf_skb_load_bytes() >>>> helper to access pkt data, which is a much more flexible interface. >>>> Mind to elaborate why you cannot use bpf_skb_load_bytes() instead? >>>> >>> >>> See my other email [1], this one is also problematic wrt SKF_LL_OFF. >>> >>> [1] http://patchwork.ozlabs.org/patch/771946/ >> >> >> Oh sorry I just find out the bpf_skb_load_bytes helper already can achieve >> the goal. There is no point to add my patch then. Thanks you for pointing >> it out and fixing it. > > If something now needs to be reverted, you need to send that revert to me. It's sitting here: http://patchwork.ozlabs.org/patch/771946/