From patchwork Fri Nov 6 22:08:03 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: 1395952 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=reject dis=none) header.from=fb.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=fb.com header.i=@fb.com header.a=rsa-sha256 header.s=facebook header.b=mXj64wap; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4CSZJs39BPz9sSf for ; Sat, 7 Nov 2020 09:08:13 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728777AbgKFWIM (ORCPT ); Fri, 6 Nov 2020 17:08:12 -0500 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:58080 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728031AbgKFWIM (ORCPT ); Fri, 6 Nov 2020 17:08:12 -0500 Received: from pps.filterd (m0109331.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 0A6LwDdE011855 for ; Fri, 6 Nov 2020 14:08:11 -0800 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=EpBdGumEfbg83utl0bIM+E+0W8/mkio6JHT2ahRoIm0=; b=mXj64wapWFK6SjPwxMMzhDfpeV7stgn2+wqQxULaGsvETkDEFuyL7UJ8eG6muI/hXNMr zMXmNKLfPNV/5be9ec6aQ9E9rqmgBFBIEUdXvlln4+SnhiOAko63HRJlbkJ7E5In/xLA QRc6JqFspqwmWRZdp0qHv3FsiFU8lZeHrz8= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 34mw5bn325-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 06 Nov 2020 14:08:11 -0800 Received: from intmgw003.03.ash8.facebook.com (2620:10d:c085:108::8) by mail.thefacebook.com (2620:10d:c085:11d::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Fri, 6 Nov 2020 14:08:10 -0800 Received: by devbig005.ftw2.facebook.com (Postfix, from userid 6611) id 8284D29463F7; Fri, 6 Nov 2020 14:08:03 -0800 (PST) From: Martin KaFai Lau To: CC: Alexei Starovoitov , Daniel Borkmann , , Subject: [PATCH bpf-next 2/3] bpf: Allow using bpf_sk_storage in FENTRY/FEXIT/RAW_TP Date: Fri, 6 Nov 2020 14:08:03 -0800 Message-ID: <20201106220803.3950648-1-kafai@fb.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20201106220750.3949423-1-kafai@fb.com> References: <20201106220750.3949423-1-kafai@fb.com> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.312,18.0.737 definitions=2020-11-06_06:2020-11-05,2020-11-06 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 malwarescore=0 bulkscore=0 spamscore=0 impostorscore=0 lowpriorityscore=0 phishscore=0 suspectscore=38 adultscore=0 mlxlogscore=999 clxscore=1015 mlxscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011060151 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This patch enables the FENTRY/FEXIT/RAW_TP tracing program to use the bpf_sk_storage_(get|delete) helper, so those tracing programs can access the sk's bpf_local_storage and the later selftest will show some examples. The bpf_sk_storage is currently used in bpf-tcp-cc, tc, cg sockops...etc which is running either in softirq or task context. This patch adds bpf_sk_storage_get_tracing_proto and bpf_sk_storage_delete_tracing_proto. They will check in runtime that the helpers can only be called when serving softirq or running in a task context. That should enable most common tracing use cases on sk. During the load time, the new tracing_allowed() function will ensure the tracing prog using the bpf_sk_storage_(get|delete) helper is not tracing any *sk_storage*() function itself. The sk is passed as "void *" when calling into bpf_local_storage. Signed-off-by: Martin KaFai Lau Acked-by: Song Liu --- include/net/bpf_sk_storage.h | 2 + kernel/trace/bpf_trace.c | 5 +++ net/core/bpf_sk_storage.c | 73 ++++++++++++++++++++++++++++++++++++ 3 files changed, 80 insertions(+) diff --git a/include/net/bpf_sk_storage.h b/include/net/bpf_sk_storage.h index 3c516dd07caf..0e85713f56df 100644 --- a/include/net/bpf_sk_storage.h +++ b/include/net/bpf_sk_storage.h @@ -20,6 +20,8 @@ void bpf_sk_storage_free(struct sock *sk); extern const struct bpf_func_proto bpf_sk_storage_get_proto; extern const struct bpf_func_proto bpf_sk_storage_delete_proto; +extern const struct bpf_func_proto bpf_sk_storage_get_tracing_proto; +extern const struct bpf_func_proto bpf_sk_storage_delete_tracing_proto; struct bpf_local_storage_elem; struct bpf_sk_storage_diag; diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index e4515b0f62a8..cfce60ad1cb5 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -16,6 +16,7 @@ #include #include #include +#include #include #include @@ -1735,6 +1736,10 @@ tracing_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_skc_to_tcp_request_sock_proto; case BPF_FUNC_skc_to_udp6_sock: return &bpf_skc_to_udp6_sock_proto; + case BPF_FUNC_sk_storage_get: + return &bpf_sk_storage_get_tracing_proto; + case BPF_FUNC_sk_storage_delete: + return &bpf_sk_storage_delete_tracing_proto; #endif case BPF_FUNC_seq_printf: return prog->expected_attach_type == BPF_TRACE_ITER ? diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c index 001eac65e40f..1a41c917e08d 100644 --- a/net/core/bpf_sk_storage.c +++ b/net/core/bpf_sk_storage.c @@ -6,6 +6,7 @@ #include #include #include +#include #include #include #include @@ -378,6 +379,78 @@ const struct bpf_func_proto bpf_sk_storage_delete_proto = { .arg2_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON, }; +static bool bpf_sk_storage_tracing_allowed(const struct bpf_prog *prog) +{ + const struct btf *btf_vmlinux; + const struct btf_type *t; + const char *tname; + u32 btf_id; + + if (prog->aux->dst_prog) + return false; + + /* Ensure the tracing program is not tracing + * any *sk_storage*() function and also + * use the bpf_sk_storage_(get|delete) helper. + */ + switch (prog->expected_attach_type) { + case BPF_TRACE_RAW_TP: + /* bpf_sk_storage has no trace point */ + return true; + case BPF_TRACE_FENTRY: + case BPF_TRACE_FEXIT: + btf_vmlinux = bpf_get_btf_vmlinux(); + btf_id = prog->aux->attach_btf_id; + t = btf_type_by_id(btf_vmlinux, btf_id); + tname = btf_name_by_offset(btf_vmlinux, t->name_off); + return !strstr(tname, "sk_storage"); + default: + return false; + } + + return false; +} + +BPF_CALL_4(bpf_sk_storage_get_tracing, struct bpf_map *, map, struct sock *, sk, + void *, value, u64, flags) +{ + if (!in_serving_softirq() && !in_task()) + return (unsigned long)NULL; + + return (unsigned long)____bpf_sk_storage_get(map, sk, value, flags); +} + +BPF_CALL_2(bpf_sk_storage_delete_tracing, struct bpf_map *, map, + struct sock *, sk) +{ + if (!in_serving_softirq() && !in_task()) + return -EPERM; + + return ____bpf_sk_storage_delete(map, sk); +} + +const struct bpf_func_proto bpf_sk_storage_get_tracing_proto = { + .func = bpf_sk_storage_get_tracing, + .gpl_only = false, + .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL, + .arg1_type = ARG_CONST_MAP_PTR, + .arg2_type = ARG_PTR_TO_BTF_ID, + .arg2_btf_id = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON], + .arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL, + .arg4_type = ARG_ANYTHING, + .allowed = bpf_sk_storage_tracing_allowed, +}; + +const struct bpf_func_proto bpf_sk_storage_delete_tracing_proto = { + .func = bpf_sk_storage_delete_tracing, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_CONST_MAP_PTR, + .arg2_type = ARG_PTR_TO_BTF_ID, + .arg2_btf_id = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON], + .allowed = bpf_sk_storage_tracing_allowed, +}; + struct bpf_sk_storage_diag { u32 nr_maps; struct bpf_map *maps[];