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=-6.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 9B4DEC4360C for ; Wed, 2 Oct 2019 20:57:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6F0B52070B for ; Wed, 2 Oct 2019 20:57:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="kTWePzep" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727793AbfJBU5U (ORCPT ); Wed, 2 Oct 2019 16:57:20 -0400 Received: from mail-qt1-f196.google.com ([209.85.160.196]:44414 "EHLO mail-qt1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725975AbfJBU5T (ORCPT ); Wed, 2 Oct 2019 16:57:19 -0400 Received: by mail-qt1-f196.google.com with SMTP id u40so509619qth.11; Wed, 02 Oct 2019 13:57:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=lBRtIu7khuvHqmEcKRJqmLxKD+g3RDOIkNxY/EmNt24=; b=kTWePzepNBi9G2bJZ8mA1g/rDGjH6Nk2yHtXNovG/ac0AAsLnQ8oVtVBXYJhzsFeXO gwrbvCKbzrU+A9z1ihqApJm8O0VVK+4j34UdCMm/rGhizVDe2LYuRyPulWKcX4eWY6kD qvWqZHOkKFeJmwhPN/DF44HPJR+sgQE6sax40WQAYxQDjYgVuiOODa56Xd/MO6ct8M2O g3u+M/J3wL2Ovt5DaGbbEhG5NfpD9bN0hL6MHIXsXodEzDovm7fOKP8CCgVLqZ9UTYBb KsVEg9eEXB44fQcqOi+PE4znXZrcCA44KS004PCeUX2miTbf7dJry5ee/8U+8NFgjYKN liVw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=lBRtIu7khuvHqmEcKRJqmLxKD+g3RDOIkNxY/EmNt24=; b=TF8ArF8XH8OClwGxxE+s8IXPzBL3Dad57ZHhBLzfYBAKQtTHU9DgyMA26H+8uqSIiP NBHwT+8WdtXx9Wt9tfiw+IXtLxa6ePIHAwgcgSX0KRAg7vOtDX21wEE5sW+KRLATqRa/ sp50ltwsLugwUYdyc5LRsXjO0QmDIdfPnhyWg/YmZfGTCewJapjKtYFMdiQSxXmX33i+ kiKB/NrLHGVxADILT5UXF00UKsUBE+cnGU88//jGETKyO0zWv4vDnx3ziftBa81ksdsI /H1nvoX+2MonNmVGs6bH6qr1OdgKgoiixGj0WWLvY//I0TK9GVEYyo8Zkl6o2ECMT5Zf I07Q== X-Gm-Message-State: APjAAAXA5VvxCOA23X9PnVeL8tnQ/CENzTQl+w9k+xjFh1qp/EngJWaH G519iuttOhpO9skVDjpBuNcMHCwgZWWgpymaHbo= X-Google-Smtp-Source: APXvYqxLTy1mtbVueW4MPazVD8PiMqUsG8g8EPrwshM1czo2mde/7BhrkkCX1p8q9TuGyK0Act2L4NSKiaTSp9yPjbY= X-Received: by 2002:ac8:37cb:: with SMTP id e11mr6530720qtc.22.1570049838775; Wed, 02 Oct 2019 13:57:18 -0700 (PDT) MIME-Version: 1.0 References: <20191002173357.253643-1-sdf@google.com> <20191002173357.253643-2-sdf@google.com> In-Reply-To: <20191002173357.253643-2-sdf@google.com> From: Song Liu Date: Wed, 2 Oct 2019 13:57:07 -0700 Message-ID: Subject: Re: [PATCH bpf-next 1/2] bpf/flow_dissector: add mode to enforce global BPF flow dissector To: Stanislav Fomichev Cc: Networking , bpf , "David S . Miller" , Alexei Starovoitov , Daniel Borkmann , Petar Penkov Content-Type: text/plain; charset="UTF-8" Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Wed, Oct 2, 2019 at 10:36 AM Stanislav Fomichev wrote: > > Always use init_net flow dissector BPF program if it's attached and fall > back to the per-net namespace one. Also, deny installing new programs if > there is already one attached to the root namespace. > Users can still detach their BPF programs, but can't attach any > new ones (-EPERM). > > Cc: Petar Penkov > Signed-off-by: Stanislav Fomichev > --- > Documentation/bpf/prog_flow_dissector.rst | 3 +++ > net/core/flow_dissector.c | 11 ++++++++++- > 2 files changed, 13 insertions(+), 1 deletion(-) > > diff --git a/Documentation/bpf/prog_flow_dissector.rst b/Documentation/bpf/prog_flow_dissector.rst > index a78bf036cadd..4d86780ab0f1 100644 > --- a/Documentation/bpf/prog_flow_dissector.rst > +++ b/Documentation/bpf/prog_flow_dissector.rst > @@ -142,3 +142,6 @@ BPF flow dissector doesn't support exporting all the metadata that in-kernel > C-based implementation can export. Notable example is single VLAN (802.1Q) > and double VLAN (802.1AD) tags. Please refer to the ``struct bpf_flow_keys`` > for a set of information that's currently can be exported from the BPF context. > + > +When BPF flow dissector is attached to the root network namespace (machine-wide > +policy), users can't override it in their child network namespaces. > diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c > index 7c09d87d3269..494e2016fe84 100644 > --- a/net/core/flow_dissector.c > +++ b/net/core/flow_dissector.c > @@ -115,6 +115,11 @@ int skb_flow_dissector_bpf_prog_attach(const union bpf_attr *attr, > struct bpf_prog *attached; > struct net *net; > > + if (rcu_access_pointer(init_net.flow_dissector_prog)) { > + /* Can't override root flow dissector program */ > + return -EPERM; Maybe -EBUSY is more accurate? Thanks, Song