From patchwork Mon Nov 21 17:05:36 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yonghong Song X-Patchwork-Id: 13051384 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DC145C4332F for ; Mon, 21 Nov 2022 17:06:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230368AbiKURF7 (ORCPT ); Mon, 21 Nov 2022 12:05:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55538 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230380AbiKURFp (ORCPT ); Mon, 21 Nov 2022 12:05:45 -0500 Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com [67.231.145.42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8ACD8CB949 for ; Mon, 21 Nov 2022 09:05:41 -0800 (PST) Received: from pps.filterd (m0148461.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 2ALCSEA2015926 for ; Mon, 21 Nov 2022 09:05:41 -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=L1Ha21rW6HuIxnnqQcXIHkz8fES1C09ioL+HsinoyV4=; b=eP1aZB20eKXRBqfd7ojMzueWc3sHCX9BOd9pG+E/D6U/7f0l2hIZe5xR0ukAwq9ujxry WoM7MnSaP42Ys6TLJh3Icaf52SHPt14V0C+l4RN/GG+13UaQHAdycdlqFbvcvPFPI1Rb K5px0XUeqvgD/oNXOweNCeG/lSAll9uv+ao= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3kxw4xx8e7-5 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Mon, 21 Nov 2022 09:05:41 -0800 Received: from twshared13940.35.frc1.facebook.com (2620:10d:c085:108::4) by mail.thefacebook.com (2620:10d:c085:11d::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Mon, 21 Nov 2022 09:05:40 -0800 Received: by devbig309.ftw3.facebook.com (Postfix, from userid 128203) id 3DE981282A606; Mon, 21 Nov 2022 09:05:36 -0800 (PST) From: Yonghong Song To: CC: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , , Martin KaFai Lau Subject: [PATCH bpf-next v7 4/4] selftests/bpf: Add tests for bpf_rcu_read_lock() Date: Mon, 21 Nov 2022 09:05:36 -0800 Message-ID: <20221121170536.1198240-1-yhs@fb.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20221121170515.1193967-1-yhs@fb.com> References: <20221121170515.1193967-1-yhs@fb.com> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-GUID: krT1dc4jbeFQ0rCgEwWYRKpw6x3XCjIZ X-Proofpoint-ORIG-GUID: krT1dc4jbeFQ0rCgEwWYRKpw6x3XCjIZ X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.219,Aquarius:18.0.895,Hydra:6.0.545,FMLib:17.11.122.1 definitions=2022-11-21_14,2022-11-18_01,2022-06-22_01 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Add a few positive/negative tests to test bpf_rcu_read_lock() and its corresponding verifier support. The new test will fail on s390x and aarch64, so an entry is added to each of their respective deny lists. Signed-off-by: Yonghong Song --- tools/testing/selftests/bpf/DENYLIST.aarch64 | 1 + tools/testing/selftests/bpf/DENYLIST.s390x | 1 + .../selftests/bpf/prog_tests/rcu_read_lock.c | 153 +++++++++ .../selftests/bpf/progs/rcu_read_lock.c | 325 ++++++++++++++++++ 4 files changed, 480 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/rcu_read_lock.c create mode 100644 tools/testing/selftests/bpf/progs/rcu_read_lock.c diff --git a/tools/testing/selftests/bpf/DENYLIST.aarch64 b/tools/testing/selftests/bpf/DENYLIST.aarch64 index affc5aebbf0f..8e77515d56f6 100644 --- a/tools/testing/selftests/bpf/DENYLIST.aarch64 +++ b/tools/testing/selftests/bpf/DENYLIST.aarch64 @@ -45,6 +45,7 @@ modify_return # modify_return__attach failed module_attach # skel_attach skeleton attach failed: -524 mptcp/base # run_test mptcp unexpected error: -524 (errno 524) netcnt # packets unexpected packets: actual 10001 != expected 10000 +rcu_read_lock # failed to attach: ERROR: strerror_r(-524)=22 recursion # skel_attach unexpected error: -524 (errno 524) ringbuf # skel_attach skeleton attachment failed: -1 setget_sockopt # attach_cgroup unexpected error: -524 diff --git a/tools/testing/selftests/bpf/DENYLIST.s390x b/tools/testing/selftests/bpf/DENYLIST.s390x index 12cf2159975e..77aabc4dc64c 100644 --- a/tools/testing/selftests/bpf/DENYLIST.s390x +++ b/tools/testing/selftests/bpf/DENYLIST.s390x @@ -42,6 +42,7 @@ module_attach # skel_attach skeleton attach failed: - mptcp netcnt # failed to load BPF skeleton 'netcnt_prog': -7 (?) probe_user # check_kprobe_res wrong kprobe res from probe read (?) +rcu_read_lock # failed to find kernel BTF type ID of '__x64_sys_getpgid': -3 (?) recursion # skel_attach unexpected error: -524 (trampoline) ringbuf # skel_load skeleton load failed (?) select_reuseport # intermittently fails on new s390x setup diff --git a/tools/testing/selftests/bpf/prog_tests/rcu_read_lock.c b/tools/testing/selftests/bpf/prog_tests/rcu_read_lock.c new file mode 100644 index 000000000000..58d5fe3da223 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/rcu_read_lock.c @@ -0,0 +1,153 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates.*/ + +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include "rcu_read_lock.skel.h" +#include "cgroup_helpers.h" + +static unsigned long long cgroup_id; + +static void test_local_storage(void) +{ + struct rcu_read_lock *skel; + int err; + + skel = rcu_read_lock__open(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + skel->bss->target_pid = syscall(SYS_gettid); + + bpf_program__set_autoload(skel->progs.get_cgroup_id, true); + bpf_program__set_autoload(skel->progs.task_succ, true); + bpf_program__set_autoload(skel->progs.two_regions, true); + bpf_program__set_autoload(skel->progs.non_sleepable_1, true); + bpf_program__set_autoload(skel->progs.non_sleepable_2, true); + err = rcu_read_lock__load(skel); + if (!ASSERT_OK(err, "skel_load")) + goto done; + + err = rcu_read_lock__attach(skel); + if (!ASSERT_OK(err, "skel_attach")) + goto done; + + syscall(SYS_getpgid); + + ASSERT_EQ(skel->bss->task_storage_val, 2, "task_storage_val"); + ASSERT_EQ(skel->bss->cgroup_id, cgroup_id, "cgroup_id"); +done: + rcu_read_lock__destroy(skel); +} + +static void test_runtime_diff_rcu_tag(void) +{ + struct rcu_read_lock *skel; + int err; + + skel = rcu_read_lock__open(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + bpf_program__set_autoload(skel->progs.dump_ipv6_route, true); + err = rcu_read_lock__load(skel); + ASSERT_OK(err, "skel_load"); + rcu_read_lock__destroy(skel); +} + +static const char * const inproper_region_tests[] = { + "miss_lock", + "miss_unlock", + "non_sleepable_rcu_mismatch", + "inproper_sleepable_helper", + "inproper_sleepable_kfunc", + "nested_rcu_region", +}; + +static void test_inproper_region(void) +{ + struct rcu_read_lock *skel; + struct bpf_program *prog; + int i, err; + + for (i = 0; i < ARRAY_SIZE(inproper_region_tests); i++) { + skel = rcu_read_lock__open(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + prog = bpf_object__find_program_by_name(skel->obj, inproper_region_tests[i]); + if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name")) + goto out; + bpf_program__set_autoload(prog, true); + err = rcu_read_lock__load(skel); + ASSERT_ERR(err, "skel_load"); +out: + rcu_read_lock__destroy(skel); + } +} + +static const char * const rcuptr_misuse_tests[] = { + "task_untrusted_ptr", + "task_incorrect_rcu_region1", + "task_incorrect_rcu_region2", + "cross_rcu_region", +}; + +static void test_rcuptr_misuse(void) +{ + struct rcu_read_lock *skel; + struct bpf_program *prog; + struct btf *vmlinux_btf; + int i, err, type_id; + + vmlinux_btf = btf__load_vmlinux_btf(); + if (!ASSERT_OK_PTR(vmlinux_btf, "could not load vmlinux BTF")) + return; + + /* skip the test if btf_type_tag("rcu") is not present in vmlinux */ + type_id = btf__find_by_name_kind(vmlinux_btf, "rcu", BTF_KIND_TYPE_TAG); + if (type_id < 0) { + test__skip(); + return; + } + + for (i = 0; i < ARRAY_SIZE(rcuptr_misuse_tests); i++) { + skel = rcu_read_lock__open(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + prog = bpf_object__find_program_by_name(skel->obj, rcuptr_misuse_tests[i]); + if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name")) + goto out; + bpf_program__set_autoload(prog, true); + err = rcu_read_lock__load(skel); + ASSERT_ERR(err, "skel_load"); +out: + rcu_read_lock__destroy(skel); + } +} + +void test_rcu_read_lock(void) +{ + int cgroup_fd; + + cgroup_fd = test__join_cgroup("/rcu_read_lock"); + if (!ASSERT_GE(cgroup_fd, 0, "join_cgroup /rcu_read_lock")) + return; + + cgroup_id = get_cgroup_id("/rcu_read_lock"); + if (test__start_subtest("local_storage")) + test_local_storage(); + if (test__start_subtest("runtime_diff_rcu_tag")) + test_runtime_diff_rcu_tag(); + if (test__start_subtest("negative_tests_inproper_region")) + test_inproper_region(); + if (test__start_subtest("negative_tests_rcuptr_misuse")) + test_rcuptr_misuse(); + + close(cgroup_fd); +} diff --git a/tools/testing/selftests/bpf/progs/rcu_read_lock.c b/tools/testing/selftests/bpf/progs/rcu_read_lock.c new file mode 100644 index 000000000000..add30d1becb1 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/rcu_read_lock.c @@ -0,0 +1,325 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ + +#include "vmlinux.h" +#include +#include +#include "bpf_tracing_net.h" +#include "bpf_misc.h" + +char _license[] SEC("license") = "GPL"; + +struct { + __uint(type, BPF_MAP_TYPE_TASK_STORAGE); + __uint(map_flags, BPF_F_NO_PREALLOC); + __type(key, int); + __type(value, long); +} map_a SEC(".maps"); + +__u32 user_data, key_serial, target_pid = 0; +__u64 flags, task_storage_val, cgroup_id; + +struct bpf_key *bpf_lookup_user_key(__u32 serial, __u64 flags) __ksym; +void bpf_key_put(struct bpf_key *key) __ksym; +void bpf_rcu_read_lock(void) __ksym; +void bpf_rcu_read_unlock(void) __ksym; + +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") +int get_cgroup_id(void *ctx) +{ + struct task_struct *task; + + task = bpf_get_current_task_btf(); + if (task->pid != target_pid) + return 0; + + /* simulate bpf_get_current_cgroup_id() helper */ + bpf_rcu_read_lock(); + cgroup_id = task->cgroups->dfl_cgrp->kn->id; + bpf_rcu_read_unlock(); + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") +int task_succ(void *ctx) +{ + struct task_struct *task, *real_parent; + long init_val = 2; + long *ptr; + + task = bpf_get_current_task_btf(); + if (task->pid != target_pid) + return 0; + + bpf_rcu_read_lock(); + /* region including helper using rcu ptr real_parent */ + real_parent = task->real_parent; + ptr = bpf_task_storage_get(&map_a, real_parent, &init_val, + BPF_LOCAL_STORAGE_GET_F_CREATE); + if (!ptr) + goto out; + ptr = bpf_task_storage_get(&map_a, real_parent, 0, 0); + if (!ptr) + goto out; + task_storage_val = *ptr; +out: + bpf_rcu_read_unlock(); + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_nanosleep") +int two_regions(void *ctx) +{ + struct task_struct *task, *real_parent; + + /* two regions */ + task = bpf_get_current_task_btf(); + bpf_rcu_read_lock(); + bpf_rcu_read_unlock(); + bpf_rcu_read_lock(); + real_parent = task->real_parent; + (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); + bpf_rcu_read_unlock(); + return 0; +} + +SEC("?fentry/" SYS_PREFIX "sys_getpgid") +int non_sleepable_1(void *ctx) +{ + struct task_struct *task, *real_parent; + + task = bpf_get_current_task_btf(); + + bpf_rcu_read_lock(); + real_parent = task->real_parent; + (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); + bpf_rcu_read_unlock(); + return 0; +} + +SEC("?fentry/" SYS_PREFIX "sys_getpgid") +int non_sleepable_2(void *ctx) +{ + struct task_struct *task, *real_parent; + + bpf_rcu_read_lock(); + task = bpf_get_current_task_btf(); + bpf_rcu_read_unlock(); + + bpf_rcu_read_lock(); + real_parent = task->real_parent; + (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); + bpf_rcu_read_unlock(); + return 0; +} + +SEC("?iter.s/ipv6_route") +int dump_ipv6_route(struct bpf_iter__ipv6_route *ctx) +{ + struct seq_file *seq = ctx->meta->seq; + struct fib6_info *rt = ctx->rt; + const struct net_device *dev; + struct fib6_nh *fib6_nh; + unsigned int flags; + struct nexthop *nh; + + if (rt == (void *)0) + return 0; + + /* fib6_nh is not a rcu ptr */ + fib6_nh = &rt->fib6_nh[0]; + flags = rt->fib6_flags; + + nh = rt->nh; + bpf_rcu_read_lock(); + if (rt->nh) + /* fib6_nh is a rcu ptr */ + fib6_nh = &nh->nh_info->fib6_nh; + + /* fib6_nh could be a rcu or non-rcu ptr */ + if (fib6_nh->fib_nh_gw_family) { + flags |= RTF_GATEWAY; + BPF_SEQ_PRINTF(seq, "%pi6 ", &fib6_nh->fib_nh_gw6); + } else { + BPF_SEQ_PRINTF(seq, "00000000000000000000000000000000 "); + } + + dev = fib6_nh->fib_nh_dev; + bpf_rcu_read_unlock(); + if (dev) + BPF_SEQ_PRINTF(seq, "%08x %08x %08x %08x %8s\n", rt->fib6_metric, + rt->fib6_ref.refs.counter, 0, flags, dev->name); + else + BPF_SEQ_PRINTF(seq, "%08x %08x %08x %08x\n", rt->fib6_metric, + rt->fib6_ref.refs.counter, 0, flags); + + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") +int miss_lock(void *ctx) +{ + struct task_struct *task; + struct css_set *cgroups; + struct cgroup *dfl_cgrp; + + /* missing bpf_rcu_read_lock() */ + task = bpf_get_current_task_btf(); + bpf_rcu_read_lock(); + (void)bpf_task_storage_get(&map_a, task, 0, 0); + bpf_rcu_read_unlock(); + bpf_rcu_read_unlock(); + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") +int miss_unlock(void *ctx) +{ + struct task_struct *task; + struct css_set *cgroups; + struct cgroup *dfl_cgrp; + + /* missing bpf_rcu_read_unlock() */ + task = bpf_get_current_task_btf(); + bpf_rcu_read_lock(); + (void)bpf_task_storage_get(&map_a, task, 0, 0); + return 0; +} + +SEC("?fentry/" SYS_PREFIX "sys_getpgid") +int non_sleepable_rcu_mismatch(void *ctx) +{ + struct task_struct *task, *real_parent; + + task = bpf_get_current_task_btf(); + + /* non-sleepable: missing bpf_rcu_read_unlock() in one path */ + bpf_rcu_read_lock(); + real_parent = task->real_parent; + (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); + if (real_parent) + bpf_rcu_read_unlock(); + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") +int inproper_sleepable_helper(void *ctx) +{ + struct task_struct *task, *real_parent; + struct pt_regs *regs; + __u32 value = 0; + void *ptr; + + task = bpf_get_current_task_btf(); + + /* sleepable helper in rcu read lock region */ + bpf_rcu_read_lock(); + real_parent = task->real_parent; + regs = (struct pt_regs *)bpf_task_pt_regs(real_parent); + if (!regs) { + bpf_rcu_read_unlock(); + return 0; + } + + ptr = (void *)PT_REGS_IP(regs); + (void)bpf_copy_from_user_task(&value, sizeof(uint32_t), ptr, task, 0); + user_data = value; + (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); + bpf_rcu_read_unlock(); + return 0; +} + +SEC("?lsm.s/bpf") +int BPF_PROG(inproper_sleepable_kfunc, int cmd, union bpf_attr *attr, unsigned int size) +{ + struct bpf_key *bkey; + + /* sleepable kfunc in rcu read lock region */ + bpf_rcu_read_lock(); + bkey = bpf_lookup_user_key(key_serial, flags); + bpf_rcu_read_unlock(); + if (!bkey) + return -1; + bpf_key_put(bkey); + + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_nanosleep") +int nested_rcu_region(void *ctx) +{ + struct task_struct *task, *real_parent; + + /* nested rcu read lock regions */ + task = bpf_get_current_task_btf(); + bpf_rcu_read_lock(); + bpf_rcu_read_lock(); + real_parent = task->real_parent; + (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); + bpf_rcu_read_unlock(); + bpf_rcu_read_unlock(); + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") +int task_untrusted_ptr(void *ctx) +{ + struct task_struct *task, *last_wakee; + + task = bpf_get_current_task_btf(); + + bpf_rcu_read_lock(); + /* the pointer last_wakee marked as untrusted */ + last_wakee = task->real_parent->last_wakee; + (void)bpf_task_storage_get(&map_a, last_wakee, 0, 0); + bpf_rcu_read_unlock(); + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") +int task_incorrect_rcu_region1(void *ctx) +{ + struct task_struct *task, *real_parent; + + task = bpf_get_current_task_btf(); + + bpf_rcu_read_lock(); + real_parent = task->real_parent; + bpf_rcu_read_unlock(); + /* helper use of rcu ptr outside the rcu read lock region */ + (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_getpgid") +int task_incorrect_rcu_region2(void *ctx) +{ + struct task_struct *task, *real_parent; + + task = bpf_get_current_task_btf(); + + /* missing bpf_rcu_read_unlock() in one path */ + bpf_rcu_read_lock(); + real_parent = task->real_parent; + (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); + if (real_parent) + bpf_rcu_read_unlock(); + return 0; +} + +SEC("?fentry.s/" SYS_PREFIX "sys_nanosleep") +int cross_rcu_region(void *ctx) +{ + struct task_struct *task, *real_parent; + + /* rcu ptr define/use in different regions */ + task = bpf_get_current_task_btf(); + bpf_rcu_read_lock(); + real_parent = task->real_parent; + bpf_rcu_read_unlock(); + bpf_rcu_read_lock(); + (void)bpf_task_storage_get(&map_a, real_parent, 0, 0); + bpf_rcu_read_unlock(); + return 0; +} +