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=-20.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable 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 5F7B5C4167B for ; Fri, 4 Dec 2020 18:57:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1F7B822CA0 for ; Fri, 4 Dec 2020 18:57:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730576AbgLDS5M (ORCPT ); Fri, 4 Dec 2020 13:57:12 -0500 Received: from www62.your-server.de ([213.133.104.62]:55538 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726021AbgLDS5L (ORCPT ); Fri, 4 Dec 2020 13:57:11 -0500 Received: from sslproxy01.your-server.de ([78.46.139.224]) by www62.your-server.de with esmtpsa (TLSv1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.92.3) (envelope-from ) id 1klGFo-00006u-Vn; Fri, 04 Dec 2020 19:56:29 +0100 Received: from [85.7.101.30] (helo=pc-9.home) by sslproxy01.your-server.de with esmtpsa (TLSv1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1klGFo-00074p-Pt; Fri, 04 Dec 2020 19:56:28 +0100 Subject: Re: [PATCH bpf-next v2 1/3] bpf: Expose bpf_get_socket_cookie to tracing programs To: Florent Revest , bpf@vger.kernel.org Cc: ast@kernel.org, andrii@kernel.org, kpsingh@chromium.org, revest@google.com, linux-kernel@vger.kernel.org References: <20201203213330.1657666-1-revest@google.com> From: Daniel Borkmann Message-ID: Date: Fri, 4 Dec 2020 19:56:28 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <20201203213330.1657666-1-revest@google.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Authenticated-Sender: daniel@iogearbox.net X-Virus-Scanned: Clear (ClamAV 0.102.4/26007/Thu Dec 3 14:13:31 2020) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/3/20 10:33 PM, Florent Revest wrote: > This creates a new helper proto because the existing > bpf_get_socket_cookie_sock_proto has a ARG_PTR_TO_CTX argument and only > works for BPF programs where the context is a sock. > > This helper could also be useful to other BPF program types such as LSM. > > Signed-off-by: Florent Revest > --- > include/uapi/linux/bpf.h | 7 +++++++ > kernel/trace/bpf_trace.c | 4 ++++ > net/core/filter.c | 7 +++++++ > tools/include/uapi/linux/bpf.h | 7 +++++++ > 4 files changed, 25 insertions(+) > > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h > index c3458ec1f30a..3e0e33c43998 100644 > --- a/include/uapi/linux/bpf.h > +++ b/include/uapi/linux/bpf.h > @@ -1662,6 +1662,13 @@ union bpf_attr { > * Return > * A 8-byte long non-decreasing number. > * > + * u64 bpf_get_socket_cookie(void *sk) > + * Description > + * Equivalent to **bpf_get_socket_cookie**\ () helper that accepts > + * *sk*, but gets socket from a BTF **struct sock**. > + * Return > + * A 8-byte long non-decreasing number. I would not mention this here since it's not fully correct and we should avoid users taking non-decreasing granted in their progs. The only assumption you can make is that it can be considered a unique number. See also [0] with reverse counter.. [0] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=92acdc58ab11af66fcaef485433fde61b5e32fac > + * > * u32 bpf_get_socket_uid(struct sk_buff *skb) > * Return > * The owner UID of the socket associated to *skb*. If the socket > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c > index d255bc9b2bfa..14ad96579813 100644 > --- a/kernel/trace/bpf_trace.c > +++ b/kernel/trace/bpf_trace.c > @@ -1725,6 +1725,8 @@ raw_tp_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) > } > } > > +extern const struct bpf_func_proto bpf_get_socket_cookie_sock_tracing_proto; > + > const struct bpf_func_proto * > tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) > { > @@ -1748,6 +1750,8 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) > return &bpf_sk_storage_get_tracing_proto; > case BPF_FUNC_sk_storage_delete: > return &bpf_sk_storage_delete_tracing_proto; > + case BPF_FUNC_get_socket_cookie: > + return &bpf_get_socket_cookie_sock_tracing_proto; > #endif > case BPF_FUNC_seq_printf: > return prog->expected_attach_type == BPF_TRACE_ITER ? > diff --git a/net/core/filter.c b/net/core/filter.c > index 2ca5eecebacf..177c4e5e529d 100644 > --- a/net/core/filter.c > +++ b/net/core/filter.c > @@ -4631,6 +4631,13 @@ static const struct bpf_func_proto bpf_get_socket_cookie_sock_proto = { > .arg1_type = ARG_PTR_TO_CTX, > }; > > +const struct bpf_func_proto bpf_get_socket_cookie_sock_tracing_proto = { > + .func = bpf_get_socket_cookie_sock, > + .gpl_only = false, > + .ret_type = RET_INTEGER, > + .arg1_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON, > +}; > +