From patchwork Thu Nov 4 07:00:16 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Liu X-Patchwork-Id: 12602609 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 10757C433EF for ; Thu, 4 Nov 2021 07:00:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E8F1161056 for ; Thu, 4 Nov 2021 07:00:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230361AbhKDHDL (ORCPT ); Thu, 4 Nov 2021 03:03:11 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:24400 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230306AbhKDHDF (ORCPT ); Thu, 4 Nov 2021 03:03:05 -0400 Received: from pps.filterd (m0148461.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.1.2/8.16.1.2) with SMTP id 1A422xpW005419 for ; Thu, 4 Nov 2021 00:00:28 -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=ncmUorEmzmbEO1AKZEZElGYsRqnoHrpi83tdM/o96ck=; b=JdJCyWddX/4fS9FPYdYUo+0EmsGO5ZoqegshHFy8bUAHTemlz89Af3UAh+kBy6rOjBDI 3P5uiLsstAXBBbpdowMa4LjFyz4S8QjU7UvgngxwRBF1OqWeMNWOJkaCJ9OSiFhey1Va 3+Mqrakv9i+K33RXuwLzk5vR22P4JtNYoK4= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 3c42t0u1c8-7 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Thu, 04 Nov 2021 00:00:28 -0700 Received: from intmgw001.38.frc1.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:82::e) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.14; Thu, 4 Nov 2021 00:00:26 -0700 Received: by devbig006.ftw2.facebook.com (Postfix, from userid 4523) id 94E9F1DC16578; Thu, 4 Nov 2021 00:00:21 -0700 (PDT) From: Song Liu To: , CC: , , , , , Song Liu Subject: [PATCH v2 bpf-next 2/2] selftests/bpf: add tests for bpf_find_vma Date: Thu, 4 Nov 2021 00:00:16 -0700 Message-ID: <20211104070016.2463668-3-songliubraving@fb.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20211104070016.2463668-1-songliubraving@fb.com> References: <20211104070016.2463668-1-songliubraving@fb.com> MIME-Version: 1.0 X-FB-Internal: Safe X-FB-Source: Intern X-Proofpoint-ORIG-GUID: kDUKVRl0qqBSyMb6Il2HLYeWu4HTSTht X-Proofpoint-GUID: kDUKVRl0qqBSyMb6Il2HLYeWu4HTSTht X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.790,Hydra:6.0.425,FMLib:17.0.607.475 definitions=2021-11-04_01,2021-11-03_01,2020-04-07_01 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501 spamscore=0 adultscore=0 lowpriorityscore=0 clxscore=1015 bulkscore=0 impostorscore=0 suspectscore=0 mlxlogscore=999 phishscore=0 mlxscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2110150000 definitions=main-2111040033 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Add tests for bpf_find_vma in perf_event program and kprobe program. The perf_event program is triggered from NMI context, so the second call of bpf_find_vma() will return -EBUSY (irq_work busy). The kprobe program, on the other hand, does not have this constraint. Also add test for illegal writes to task or vma from the callback function. The verifier should reject both cases. Signed-off-by: Song Liu --- .../selftests/bpf/prog_tests/find_vma.c | 115 ++++++++++++++++++ tools/testing/selftests/bpf/progs/find_vma.c | 70 +++++++++++ .../selftests/bpf/progs/find_vma_fail1.c | 30 +++++ .../selftests/bpf/progs/find_vma_fail2.c | 30 +++++ 4 files changed, 245 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/find_vma.c create mode 100644 tools/testing/selftests/bpf/progs/find_vma.c create mode 100644 tools/testing/selftests/bpf/progs/find_vma_fail1.c create mode 100644 tools/testing/selftests/bpf/progs/find_vma_fail2.c diff --git a/tools/testing/selftests/bpf/prog_tests/find_vma.c b/tools/testing/selftests/bpf/prog_tests/find_vma.c new file mode 100644 index 0000000000000..3955a92d4c152 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/find_vma.c @@ -0,0 +1,115 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ +#include +#include +#include +#include "find_vma.skel.h" +#include "find_vma_fail1.skel.h" +#include "find_vma_fail2.skel.h" + +static void test_and_reset_skel(struct find_vma *skel, int expected_find_zero_ret) +{ + ASSERT_EQ(skel->bss->found_vm_exec, 1, "found_vm_exec"); + ASSERT_EQ(skel->data->find_addr_ret, 0, "find_addr_ret"); + ASSERT_EQ(skel->data->find_zero_ret, expected_find_zero_ret, "find_zero_ret"); + ASSERT_OK_PTR(strstr(skel->bss->d_iname, "test_progs"), "find_test_progs"); + + skel->bss->found_vm_exec = 0; + skel->data->find_addr_ret = -1; + skel->data->find_zero_ret = -1; + skel->bss->d_iname[0] = 0; +} + +static int open_pe(void) +{ + struct perf_event_attr attr = {0}; + int pfd; + + /* create perf event */ + attr.size = sizeof(attr); + attr.type = PERF_TYPE_HARDWARE; + attr.config = PERF_COUNT_HW_CPU_CYCLES; + attr.freq = 1; + attr.sample_freq = 4000; + pfd = syscall(__NR_perf_event_open, &attr, 0, -1, -1, PERF_FLAG_FD_CLOEXEC); + + return pfd >= 0 ? pfd : -errno; +} + +static void test_find_vma_pe(struct find_vma *skel) +{ + struct bpf_link *link = NULL; + volatile int j = 0; + int pfd = -1, i; + + pfd = open_pe(); + if (pfd < 0) { + if (pfd == -ENOENT || pfd == -EOPNOTSUPP) { + printf("%s:SKIP:no PERF_COUNT_HW_CPU_CYCLES\n", __func__); + test__skip(); + } + if (!ASSERT_GE(pfd, 0, "perf_event_open")) + goto cleanup; + } + + link = bpf_program__attach_perf_event(skel->progs.handle_pe, pfd); + if (!ASSERT_OK_PTR(link, "attach_perf_event")) + goto cleanup; + + for (i = 0; i < 1000000; ++i) + ++j; + + test_and_reset_skel(skel, -EBUSY /* in nmi, irq_work is busy */); +cleanup: + bpf_link__destroy(link); + close(pfd); + /* caller will clean up skel */ +} + +static void test_find_vma_kprobe(struct find_vma *skel) +{ + int err; + + err = find_vma__attach(skel); + if (!ASSERT_OK(err, "get_branch_snapshot__attach")) + return; /* caller will cleanup skel */ + + getpgid(skel->bss->target_pid); + test_and_reset_skel(skel, -ENOENT /* could not find vma for ptr 0 */); +} + +static void test_illegal_write_vma(void) +{ + struct find_vma_fail1 *skel; + + skel = find_vma_fail1__open_and_load(); + ASSERT_ERR_PTR(skel, "find_vma_fail1__open_and_load"); +} + +static void test_illegal_write_task(void) +{ + struct find_vma_fail2 *skel; + + skel = find_vma_fail2__open_and_load(); + ASSERT_ERR_PTR(skel, "find_vma_fail2__open_and_load"); +} + +void serial_test_find_vma(void) +{ + struct find_vma *skel; + + skel = find_vma__open_and_load(); + if (!ASSERT_OK_PTR(skel, "find_vma__open_and_load")) + return; + + skel->bss->target_pid = getpid(); + skel->bss->addr = (__u64)test_find_vma_pe; + + test_find_vma_pe(skel); + usleep(100000); /* allow the irq_work to finish */ + test_find_vma_kprobe(skel); + + find_vma__destroy(skel); + test_illegal_write_vma(); + test_illegal_write_task(); +} diff --git a/tools/testing/selftests/bpf/progs/find_vma.c b/tools/testing/selftests/bpf/progs/find_vma.c new file mode 100644 index 0000000000000..2776718a54e29 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/find_vma.c @@ -0,0 +1,70 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ +#include "vmlinux.h" +#include +#include + +char _license[] SEC("license") = "GPL"; + +struct callback_ctx { + int dummy; +}; + +#define VM_EXEC 0x00000004 +#define DNAME_INLINE_LEN 32 + +pid_t target_pid = 0; +char d_iname[DNAME_INLINE_LEN] = {0}; +__u32 found_vm_exec = 0; +__u64 addr = 0; +int find_zero_ret = -1; +int find_addr_ret = -1; + +static __u64 +check_vma(struct task_struct *task, struct vm_area_struct *vma, + struct callback_ctx *data) +{ + if (vma->vm_file) + bpf_probe_read_kernel_str(d_iname, DNAME_INLINE_LEN - 1, + vma->vm_file->f_path.dentry->d_iname); + + /* check for VM_EXEC */ + if (vma->vm_flags & VM_EXEC) + found_vm_exec = 1; + + return 0; +} + +SEC("kprobe/__x64_sys_getpgid") +int handle_getpid(void) +{ + struct task_struct *task = bpf_get_current_task_btf(); + struct callback_ctx data = {0}; + + if (task->pid != target_pid) + return 0; + + find_addr_ret = bpf_find_vma(task, addr, check_vma, &data, 0); + + /* this should return -ENOENT */ + find_zero_ret = bpf_find_vma(task, 0, check_vma, &data, 0); + return 0; +} + +SEC("perf_event") +int handle_pe(void) +{ + struct task_struct *task = bpf_get_current_task_btf(); + struct callback_ctx data = {0}; + + if (task->pid != target_pid) + return 0; + + find_addr_ret = bpf_find_vma(task, addr, check_vma, &data, 0); + + /* In NMI, this should return -EBUSY, as the previous call is using + * the irq_work. + */ + find_zero_ret = bpf_find_vma(task, 0, check_vma, &data, 0); + return 0; +} diff --git a/tools/testing/selftests/bpf/progs/find_vma_fail1.c b/tools/testing/selftests/bpf/progs/find_vma_fail1.c new file mode 100644 index 0000000000000..d17bdcdf76f07 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/find_vma_fail1.c @@ -0,0 +1,30 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ +#include "vmlinux.h" +#include + +char _license[] SEC("license") = "GPL"; + +struct callback_ctx { + int dummy; +}; + +static __u64 +write_vma(struct task_struct *task, struct vm_area_struct *vma, + struct callback_ctx *data) +{ + /* writing to vma, which is illegal */ + vma->vm_flags |= 0x55; + + return 0; +} + +SEC("kprobe/__x64_sys_getpgid") +int handle_getpid(void) +{ + struct task_struct *task = bpf_get_current_task_btf(); + struct callback_ctx data = {0}; + + bpf_find_vma(task, 0, write_vma, &data, 0); + return 0; +} diff --git a/tools/testing/selftests/bpf/progs/find_vma_fail2.c b/tools/testing/selftests/bpf/progs/find_vma_fail2.c new file mode 100644 index 0000000000000..079c4594c095d --- /dev/null +++ b/tools/testing/selftests/bpf/progs/find_vma_fail2.c @@ -0,0 +1,30 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ +#include "vmlinux.h" +#include + +char _license[] SEC("license") = "GPL"; + +struct callback_ctx { + int dummy; +}; + +static __u64 +write_task(struct task_struct *task, struct vm_area_struct *vma, + struct callback_ctx *data) +{ + /* writing to task, which is illegal */ + task->mm = NULL; + + return 0; +} + +SEC("kprobe/__x64_sys_getpgid") +int handle_getpid(void) +{ + struct task_struct *task = bpf_get_current_task_btf(); + struct callback_ctx data = {0}; + + bpf_find_vma(task, 0, write_task, &data, 0); + return 0; +}