From patchwork Tue Sep 22 07:04:22 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Martin KaFai Lau X-Patchwork-Id: 260408 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=-14.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT 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 5FEB4C2D0E2 for ; Tue, 22 Sep 2020 07:32:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CA16C238D6 for ; Tue, 22 Sep 2020 07:32:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="k/2AW8Rt" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730142AbgIVHcq (ORCPT ); Tue, 22 Sep 2020 03:32:46 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:61324 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729894AbgIVHcp (ORCPT ); Tue, 22 Sep 2020 03:32:45 -0400 Received: from pps.filterd (m0044012.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 08M71MxS025767 for ; Tue, 22 Sep 2020 00:04:28 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=facebook; bh=Dd/vVaiblO9snO9K19DZI9P7jxx+FmFizupXFsCsIQI=; b=k/2AW8Rt5lV9tu81cnAawWhwc12eRcFTHSzp6Rcz8wjhY91Jzv/q2GfZw116nu5oiBCc zP6lpdznwCvlcmvpHvIJ0ybynCCnc6RxGc0XE2k5oJ7m6QFoO5isRU6fiIdv5EmXZvFz QO4Os4s9ej9reh3uG5Q5xJozMOUlzHYbmeQ= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 33p226hbq2-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 22 Sep 2020 00:04:28 -0700 Received: from intmgw004.03.ash8.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:82::d) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Tue, 22 Sep 2020 00:04:26 -0700 Received: by devbig005.ftw2.facebook.com (Postfix, from userid 6611) id 24222294641C; Tue, 22 Sep 2020 00:04:22 -0700 (PDT) From: Martin KaFai Lau To: CC: Alexei Starovoitov , Daniel Borkmann , , Lorenz Bauer , Subject: [PATCH v3 bpf-next 02/11] bpf: Enable bpf_skc_to_* sock casting helper to networking prog type Date: Tue, 22 Sep 2020 00:04:22 -0700 Message-ID: <20200922070422.1917351-1-kafai@fb.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200922070409.1914988-1-kafai@fb.com> References: <20200922070409.1914988-1-kafai@fb.com> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235, 18.0.687 definitions=2020-09-22_05:2020-09-21,2020-09-22 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 clxscore=1015 mlxscore=0 phishscore=0 priorityscore=1501 adultscore=0 malwarescore=0 suspectscore=13 spamscore=0 impostorscore=0 bulkscore=0 mlxlogscore=993 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2009220056 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org There is a constant need to add more fields into the bpf_tcp_sock for the bpf programs running at tc, sock_ops...etc. A current workaround could be to use bpf_probe_read_kernel(). However, other than making another helper call for reading each field and missing CO-RE, it is also not as intuitive to use as directly reading "tp->lsndtime" for example. While already having perfmon cap to do bpf_probe_read_kernel(), it will be much easier if the bpf prog can directly read from the tcp_sock. This patch tries to do that by using the existing casting-helpers bpf_skc_to_*() whose func_proto returns a btf_id. For example, the func_proto of bpf_skc_to_tcp_sock returns the btf_id of the kernel "struct tcp_sock". These helpers are also added to is_ptr_cast_function(). It ensures the returning reg (BPF_REF_0) will also carries the ref_obj_id. That will keep the ref-tracking works properly. The bpf_skc_to_* helpers are made available to most of the bpf prog types in filter.c. They are limited by perfmon cap. This patch adds a ARG_PTR_TO_BTF_ID_SOCK_COMMON. The helper accepting this arg can accept a btf-id-ptr (PTR_TO_BTF_ID + &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON]) or a legacy-ctx-convert-skc-ptr (PTR_TO_SOCK_COMMON). The bpf_skc_to_*() helpers are changed to take ARG_PTR_TO_BTF_ID_SOCK_COMMON such that they will accept pointer obtained from skb->sk. PTR_TO_*_OR_NULL is not accepted as an ARG_PTR_TO_BTF_ID_SOCK_COMMON at verification time. All PTR_TO_*_OR_NULL reg has to do a NULL check first before passing into the helper or else the bpf prog will be rejected by the verifier. [ ARG_PTR_TO_SOCK_COMMON_OR_NULL was attempted earlier. The _OR_NULL was needed because the PTR_TO_BTF_ID could be NULL but note that a could be NULL PTR_TO_BTF_ID is not a scalar NULL to the verifier. "_OR_NULL" implicitly gives an expectation that the helper can take a scalar NULL which does not make sense in most (except one) helpers. Passing scalar NULL should be rejected at the verification time. Thus, this patch uses ARG_PTR_TO_BTF_ID_SOCK_COMMON to specify that the helper can take both the btf-id ptr or the legacy PTR_TO_SOCK_COMMON but not scalar NULL. It requires the func_proto to explicitly specify the arg_btf_id such that there is a very clear expectation that the helper can handle a NULL PTR_TO_BTF_ID. ] [ ARG_PTR_TO_BTF_ID_SOCK_COMMON will be used to replace ARG_PTR_TO_SOCK* of other existing helpers later such that those existing helpers can take the PTR_TO_BTF_ID returned by the bpf_skc_to_*() helpers. The only special case is bpf_sk_lookup_assign() which can accept a scalar NULL ptr. It has to be handled specially in another follow up patch (e.g. by renaming ARG_PTR_TO_SOCKET_OR_NULL to ARG_PTR_TO_BTF_ID_SOCK_COMMON_OR_NULL). ] [ When converting the older helpers that take ARG_PTR_TO_SOCK* in the later patch, if the kernel does not support BTF, ARG_PTR_TO_BTF_ID_SOCK_COMMON will behave like ARG_PTR_TO_SOCK_COMMON because no reg->type could have PTR_TO_BTF_ID in this case. It is not a concern for the newer-btf-only helper like the bpf_skc_to_*() here though because these helpers must require BTF vmlinux to begin with. ] Signed-off-by: Martin KaFai Lau --- include/linux/bpf.h | 1 + kernel/bpf/verifier.c | 28 ++++++++++++++++--- net/core/filter.c | 64 +++++++++++++++++++++++++++++++++---------- 3 files changed, 74 insertions(+), 19 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index fc5c901c7542..d0937f1d2980 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -292,6 +292,7 @@ enum bpf_arg_type { ARG_PTR_TO_ALLOC_MEM, /* pointer to dynamically allocated memory */ ARG_PTR_TO_ALLOC_MEM_OR_NULL, /* pointer to dynamically allocated memory or NULL */ ARG_CONST_ALLOC_SIZE_OR_ZERO, /* number of allocated bytes requested */ + ARG_PTR_TO_BTF_ID_SOCK_COMMON, /* pointer to in-kernel sock_common or bpf-mirrored bpf_sock */ __BPF_ARG_TYPE_MAX, }; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 3ce61c412ea0..2468533bc4a1 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -486,7 +486,12 @@ static bool is_acquire_function(enum bpf_func_id func_id, static bool is_ptr_cast_function(enum bpf_func_id func_id) { return func_id == BPF_FUNC_tcp_sock || - func_id == BPF_FUNC_sk_fullsock; + func_id == BPF_FUNC_sk_fullsock || + func_id == BPF_FUNC_skc_to_tcp_sock || + func_id == BPF_FUNC_skc_to_tcp6_sock || + func_id == BPF_FUNC_skc_to_udp6_sock || + func_id == BPF_FUNC_skc_to_tcp_timewait_sock || + func_id == BPF_FUNC_skc_to_tcp_request_sock; } /* string representation of 'enum bpf_reg_type' */ @@ -3973,6 +3978,16 @@ static const struct bpf_reg_types sock_types = { }, }; +static const struct bpf_reg_types btf_id_sock_common_types = { + .types = { + PTR_TO_SOCK_COMMON, + PTR_TO_SOCKET, + PTR_TO_TCP_SOCK, + PTR_TO_XDP_SOCK, + PTR_TO_BTF_ID, + }, +}; + static const struct bpf_reg_types mem_types = { .types = { PTR_TO_STACK, @@ -4014,6 +4029,7 @@ static const struct bpf_reg_types *compatible_reg_types[] = { [ARG_PTR_TO_CTX] = &context_types, [ARG_PTR_TO_CTX_OR_NULL] = &context_types, [ARG_PTR_TO_SOCK_COMMON] = &sock_types, + [ARG_PTR_TO_BTF_ID_SOCK_COMMON] = &btf_id_sock_common_types, [ARG_PTR_TO_SOCKET] = &fullsock_types, [ARG_PTR_TO_SOCKET_OR_NULL] = &fullsock_types, [ARG_PTR_TO_BTF_ID] = &btf_ptr_types, @@ -4579,9 +4595,13 @@ static bool check_btf_id_ok(const struct bpf_func_proto *fn) { int i; - for (i = 0; i < ARRAY_SIZE(fn->arg_type); i++) - if (fn->arg_type[i] == ARG_PTR_TO_BTF_ID && !fn->arg_btf_id[i]) - return false; + for (i = 0; i < ARRAY_SIZE(fn->arg_type); i++) { + if (fn->arg_type[i] == ARG_PTR_TO_BTF_ID || + fn->arg_type[i] == ARG_PTR_TO_BTF_ID_SOCK_COMMON) { + if (!fn->arg_btf_id[i]) + return false; + } + } return true; } diff --git a/net/core/filter.c b/net/core/filter.c index 6014e5f40c58..54b338de4bb8 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -77,6 +77,9 @@ #include #include +static const struct bpf_func_proto * +bpf_sk_base_func_proto(enum bpf_func_id func_id); + int copy_bpf_fprog_from_user(struct sock_fprog *dst, sockptr_t src, int len) { if (in_compat_syscall()) { @@ -6619,7 +6622,7 @@ sock_addr_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return NULL; } default: - return bpf_base_func_proto(func_id); + return bpf_sk_base_func_proto(func_id); } } @@ -6638,7 +6641,7 @@ sk_filter_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) case BPF_FUNC_perf_event_output: return &bpf_skb_event_output_proto; default: - return bpf_base_func_proto(func_id); + return bpf_sk_base_func_proto(func_id); } } @@ -6799,7 +6802,7 @@ tc_cls_act_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_sk_assign_proto; #endif default: - return bpf_base_func_proto(func_id); + return bpf_sk_base_func_proto(func_id); } } @@ -6840,7 +6843,7 @@ xdp_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_tcp_gen_syncookie_proto; #endif default: - return bpf_base_func_proto(func_id); + return bpf_sk_base_func_proto(func_id); } } @@ -6882,7 +6885,7 @@ sock_ops_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_tcp_sock_proto; #endif /* CONFIG_INET */ default: - return bpf_base_func_proto(func_id); + return bpf_sk_base_func_proto(func_id); } } @@ -6928,7 +6931,7 @@ sk_msg_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_get_cgroup_classid_curr_proto; #endif default: - return bpf_base_func_proto(func_id); + return bpf_sk_base_func_proto(func_id); } } @@ -6970,7 +6973,7 @@ sk_skb_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_skc_lookup_tcp_proto; #endif default: - return bpf_base_func_proto(func_id); + return bpf_sk_base_func_proto(func_id); } } @@ -6981,7 +6984,7 @@ flow_dissector_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) case BPF_FUNC_skb_load_bytes: return &bpf_flow_dissector_load_bytes_proto; default: - return bpf_base_func_proto(func_id); + return bpf_sk_base_func_proto(func_id); } } @@ -7008,7 +7011,7 @@ lwt_out_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) case BPF_FUNC_skb_under_cgroup: return &bpf_skb_under_cgroup_proto; default: - return bpf_base_func_proto(func_id); + return bpf_sk_base_func_proto(func_id); } } @@ -9745,7 +9748,7 @@ sk_lookup_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) case BPF_FUNC_sk_release: return &bpf_sk_release_proto; default: - return bpf_base_func_proto(func_id); + return bpf_sk_base_func_proto(func_id); } } @@ -9912,7 +9915,7 @@ const struct bpf_func_proto bpf_skc_to_tcp6_sock_proto = { .func = bpf_skc_to_tcp6_sock, .gpl_only = false, .ret_type = RET_PTR_TO_BTF_ID_OR_NULL, - .arg1_type = ARG_PTR_TO_BTF_ID, + .arg1_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON, .arg1_btf_id = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON], .ret_btf_id = &btf_sock_ids[BTF_SOCK_TYPE_TCP6], }; @@ -9929,7 +9932,7 @@ const struct bpf_func_proto bpf_skc_to_tcp_sock_proto = { .func = bpf_skc_to_tcp_sock, .gpl_only = false, .ret_type = RET_PTR_TO_BTF_ID_OR_NULL, - .arg1_type = ARG_PTR_TO_BTF_ID, + .arg1_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON, .arg1_btf_id = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON], .ret_btf_id = &btf_sock_ids[BTF_SOCK_TYPE_TCP], }; @@ -9953,7 +9956,7 @@ const struct bpf_func_proto bpf_skc_to_tcp_timewait_sock_proto = { .func = bpf_skc_to_tcp_timewait_sock, .gpl_only = false, .ret_type = RET_PTR_TO_BTF_ID_OR_NULL, - .arg1_type = ARG_PTR_TO_BTF_ID, + .arg1_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON, .arg1_btf_id = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON], .ret_btf_id = &btf_sock_ids[BTF_SOCK_TYPE_TCP_TW], }; @@ -9977,7 +9980,7 @@ const struct bpf_func_proto bpf_skc_to_tcp_request_sock_proto = { .func = bpf_skc_to_tcp_request_sock, .gpl_only = false, .ret_type = RET_PTR_TO_BTF_ID_OR_NULL, - .arg1_type = ARG_PTR_TO_BTF_ID, + .arg1_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON, .arg1_btf_id = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON], .ret_btf_id = &btf_sock_ids[BTF_SOCK_TYPE_TCP_REQ], }; @@ -9999,7 +10002,38 @@ const struct bpf_func_proto bpf_skc_to_udp6_sock_proto = { .func = bpf_skc_to_udp6_sock, .gpl_only = false, .ret_type = RET_PTR_TO_BTF_ID_OR_NULL, - .arg1_type = ARG_PTR_TO_BTF_ID, + .arg1_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON, .arg1_btf_id = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON], .ret_btf_id = &btf_sock_ids[BTF_SOCK_TYPE_UDP6], }; + +static const struct bpf_func_proto * +bpf_sk_base_func_proto(enum bpf_func_id func_id) +{ + const struct bpf_func_proto *func; + + switch (func_id) { + case BPF_FUNC_skc_to_tcp6_sock: + func = &bpf_skc_to_tcp6_sock_proto; + break; + case BPF_FUNC_skc_to_tcp_sock: + func = &bpf_skc_to_tcp_sock_proto; + break; + case BPF_FUNC_skc_to_tcp_timewait_sock: + func = &bpf_skc_to_tcp_timewait_sock_proto; + break; + case BPF_FUNC_skc_to_tcp_request_sock: + func = &bpf_skc_to_tcp_request_sock_proto; + break; + case BPF_FUNC_skc_to_udp6_sock: + func = &bpf_skc_to_udp6_sock_proto; + break; + default: + return bpf_base_func_proto(func_id); + } + + if (!perfmon_capable()) + return NULL; + + return func; +}