From patchwork Sat May 9 17:59:00 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yonghong Song X-Patchwork-Id: 219550 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=-9.9 required=3.0 tests=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, USER_AGENT_GIT 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 3925BC47247 for ; Sat, 9 May 2020 17:59:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1D49B208CA for ; Sat, 9 May 2020 17:59:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="Jl7L+QY4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728487AbgEIR7L (ORCPT ); Sat, 9 May 2020 13:59:11 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:31482 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728285AbgEIR7J (ORCPT ); Sat, 9 May 2020 13:59:09 -0400 Received: from pps.filterd (m0109333.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 049HuRQm026183 for ; Sat, 9 May 2020 10:59:08 -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=VjcbeQyupxxr7TBBM42dTgTHtKEbd0k1bvjvsKdwakE=; b=Jl7L+QY4J2KERPoTnruEKfk6S9SZ0fYnMQIGR6uzuOLBz74eaP+XNRhFxgDj4MVm22kA K7L0RlXPA4zvdCmxcbCF/uKJ3CSC+ETFWqshPgipm8wk07MYdno+FCITYv1IKxJ3njPI D0kmN8wBpNNVJFuawJRgi8J5EUmxjivn1mE= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 30wsbq1haw-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Sat, 09 May 2020 10:59:08 -0700 Received: from intmgw002.08.frc2.facebook.com (2620:10d:c085:108::4) by mail.thefacebook.com (2620:10d:c085:11d::4) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1847.3; Sat, 9 May 2020 10:59:07 -0700 Received: by devbig003.ftw2.facebook.com (Postfix, from userid 128203) id 86B5237008E2; Sat, 9 May 2020 10:59:00 -0700 (PDT) Smtp-Origin-Hostprefix: devbig From: Yonghong Song Smtp-Origin-Hostname: devbig003.ftw2.facebook.com To: Andrii Nakryiko , , Martin KaFai Lau , CC: Alexei Starovoitov , Daniel Borkmann , Smtp-Origin-Cluster: ftw2c04 Subject: [PATCH bpf-next v4 02/21] bpf: allow loading of a bpf_iter program Date: Sat, 9 May 2020 10:59:00 -0700 Message-ID: <20200509175900.2474947-1-yhs@fb.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200509175859.2474608-1-yhs@fb.com> References: <20200509175859.2474608-1-yhs@fb.com> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.216, 18.0.676 definitions=2020-05-09_06:2020-05-08,2020-05-09 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 malwarescore=0 lowpriorityscore=0 suspectscore=0 adultscore=0 spamscore=0 bulkscore=0 phishscore=0 clxscore=1015 mlxscore=0 priorityscore=1501 impostorscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2005090155 X-FB-Internal: deliver Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org A bpf_iter program is a tracing program with attach type BPF_TRACE_ITER. The load attribute attach_btf_id is used by the verifier against a particular kernel function, which represents a target, e.g., __bpf_iter__bpf_map for target bpf_map which is implemented later. The program return value must be 0 or 1 for now. 0 : successful, except potential seq_file buffer overflow which is handled by seq_file reader. 1 : request to restart the same object In the future, other return values may be used for filtering or teminating the iterator. Acked-by: Andrii Nakryiko Signed-off-by: Yonghong Song --- include/linux/bpf.h | 3 +++ include/uapi/linux/bpf.h | 1 + kernel/bpf/bpf_iter.c | 36 ++++++++++++++++++++++++++++++++++ kernel/bpf/verifier.c | 21 ++++++++++++++++++++ tools/include/uapi/linux/bpf.h | 1 + 5 files changed, 62 insertions(+) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 40c78b86fe38..f28bdd714754 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1127,6 +1127,8 @@ struct bpf_link *bpf_link_get_from_fd(u32 ufd); int bpf_obj_pin_user(u32 ufd, const char __user *pathname); int bpf_obj_get_user(const char __user *pathname, int flags); +#define BPF_ITER_FUNC_PREFIX "__bpf_iter__" + typedef int (*bpf_iter_init_seq_priv_t)(void *private_data); typedef void (*bpf_iter_fini_seq_priv_t)(void *private_data); @@ -1140,6 +1142,7 @@ struct bpf_iter_reg { int bpf_iter_reg_target(struct bpf_iter_reg *reg_info); void bpf_iter_unreg_target(const char *target); +bool bpf_iter_prog_supported(struct bpf_prog *prog); int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value); int bpf_percpu_array_copy(struct bpf_map *map, void *key, void *value); diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 6e5e7caa3739..c8a5325cc8d0 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -218,6 +218,7 @@ enum bpf_attach_type { BPF_TRACE_FEXIT, BPF_MODIFY_RETURN, BPF_LSM_MAC, + BPF_TRACE_ITER, __MAX_BPF_ATTACH_TYPE }; diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c index 5a8119d17d14..dec182d8395a 100644 --- a/kernel/bpf/bpf_iter.c +++ b/kernel/bpf/bpf_iter.c @@ -12,6 +12,7 @@ struct bpf_iter_target_info { bpf_iter_init_seq_priv_t init_seq_private; bpf_iter_fini_seq_priv_t fini_seq_private; u32 seq_priv_size; + u32 btf_id; /* cached value */ }; static struct list_head targets = LIST_HEAD_INIT(targets); @@ -57,3 +58,38 @@ void bpf_iter_unreg_target(const char *target) WARN_ON(found == false); } + +static void cache_btf_id(struct bpf_iter_target_info *tinfo, + struct bpf_prog *prog) +{ + tinfo->btf_id = prog->aux->attach_btf_id; +} + +bool bpf_iter_prog_supported(struct bpf_prog *prog) +{ + const char *attach_fname = prog->aux->attach_func_name; + u32 prog_btf_id = prog->aux->attach_btf_id; + const char *prefix = BPF_ITER_FUNC_PREFIX; + struct bpf_iter_target_info *tinfo; + int prefix_len = strlen(prefix); + bool supported = false; + + if (strncmp(attach_fname, prefix, prefix_len)) + return false; + + mutex_lock(&targets_mutex); + list_for_each_entry(tinfo, &targets, list) { + if (tinfo->btf_id && tinfo->btf_id == prog_btf_id) { + supported = true; + break; + } + if (!strcmp(attach_fname + prefix_len, tinfo->target)) { + cache_btf_id(tinfo, prog); + supported = true; + break; + } + } + mutex_unlock(&targets_mutex); + + return supported; +} diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 70ad009577f8..d725ff7d11db 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -7101,6 +7101,10 @@ static int check_return_code(struct bpf_verifier_env *env) return 0; range = tnum_const(0); break; + case BPF_PROG_TYPE_TRACING: + if (env->prog->expected_attach_type != BPF_TRACE_ITER) + return 0; + break; default: return 0; } @@ -10481,6 +10485,7 @@ static int check_attach_btf_id(struct bpf_verifier_env *env) struct bpf_prog *tgt_prog = prog->aux->linked_prog; u32 btf_id = prog->aux->attach_btf_id; const char prefix[] = "btf_trace_"; + struct btf_func_model fmodel; int ret = 0, subprog = -1, i; struct bpf_trampoline *tr; const struct btf_type *t; @@ -10622,6 +10627,22 @@ static int check_attach_btf_id(struct bpf_verifier_env *env) prog->aux->attach_func_proto = t; prog->aux->attach_btf_trace = true; return 0; + case BPF_TRACE_ITER: + if (!btf_type_is_func(t)) { + verbose(env, "attach_btf_id %u is not a function\n", + btf_id); + return -EINVAL; + } + t = btf_type_by_id(btf, t->type); + if (!btf_type_is_func_proto(t)) + return -EINVAL; + prog->aux->attach_func_name = tname; + prog->aux->attach_func_proto = t; + if (!bpf_iter_prog_supported(prog)) + return -EINVAL; + ret = btf_distill_func_proto(&env->log, btf, t, + tname, &fmodel); + return ret; default: if (!prog_extension) return -EINVAL; diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 6e5e7caa3739..c8a5325cc8d0 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -218,6 +218,7 @@ enum bpf_attach_type { BPF_TRACE_FEXIT, BPF_MODIFY_RETURN, BPF_LSM_MAC, + BPF_TRACE_ITER, __MAX_BPF_ATTACH_TYPE };