From patchwork Wed Sep 7 14:59:39 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roberto Sassu X-Patchwork-Id: 12969092 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 7B2D5C6FA86 for ; Wed, 7 Sep 2022 15:01:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230311AbiIGPA7 (ORCPT ); Wed, 7 Sep 2022 11:00:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51634 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230242AbiIGPAm (ORCPT ); Wed, 7 Sep 2022 11:00:42 -0400 Received: from frasgout12.his.huawei.com (frasgout12.his.huawei.com [14.137.139.154]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2C1989A98C; Wed, 7 Sep 2022 08:00:40 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.18.147.227]) by frasgout12.his.huawei.com (SkyGuard) with ESMTP id 4MN51T3C6sz9y0jm; Wed, 7 Sep 2022 22:56:29 +0800 (CST) Received: from huaweicloud.com (unknown [10.204.63.22]) by APP1 (Coremail) with SMTP id LxC2BwDXzpLssRhjiXMsAA--.45146S2; Wed, 07 Sep 2022 16:00:10 +0100 (CET) From: Roberto Sassu To: memxor@gmail.com Cc: andrii@kernel.org, ast@kernel.org, bpf@vger.kernel.org, daniel@iogearbox.net, deso@posteo.net, dhowells@redhat.com, haoluo@google.com, jarkko@kernel.org, jmorris@namei.org, john.fastabend@gmail.com, jolsa@kernel.org, keyrings@vger.kernel.org, kpsingh@kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-security-module@vger.kernel.org, martin.lau@linux.dev, mingo@redhat.com, mykolal@fb.com, paul@paul-moore.com, roberto.sassu@huawei.com, roberto.sassu@huaweicloud.com, rostedt@goodmis.org, sdf@google.com, serge@hallyn.com, shuah@kernel.org, song@kernel.org, yhs@fb.com Subject: [PATCH v17 12/12] selftests/bpf: Add tests for dynamic pointers parameters in kfuncs Date: Wed, 7 Sep 2022 16:59:39 +0200 Message-Id: <20220907145939.489784-1-roberto.sassu@huaweicloud.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 X-CM-TRANSID: LxC2BwDXzpLssRhjiXMsAA--.45146S2 X-Coremail-Antispam: 1UD129KBjvJXoW3JryUJryxurWUCFy5ur48JFb_yoWftr1kpa yrWryj9r40q3W3Xrn8JFs7ur4fKr48Zw17CrZI9FyxZr1DXFZ3XF18KFy3t3Z8K395Xw45 Z3ySqFWruw4UJa7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUva14x267AKxVWrJVCq3wAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWUuVWrJwAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26r1j6r1xM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26F4j 6r4UJwA2z4x0Y4vEx4A2jsIE14v26r4j6F4UM28EF7xvwVC2z280aVCY1x0267AKxVW8Jr 0_Cr1UM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj 6xIIjxv20xvE14v26r106r15McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_Jr 0_Gr1lF7xvr2IYc2Ij64vIr41lF7I21c0EjII2zVCS5cI20VAGYxC7M4IIrI8v6xkF7I0E 8cxan2IY04v7MxAIw28IcxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I 8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVW8ZVWr XwCIc40Y0x0EwIxGrwCI42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x 0267AKxVWxJVW8Jr1lIxAIcVCF04k26cxKx2IYs7xG6rWUJVWrZr1UMIIF0xvEx4A2jsIE 14v26r1j6r4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_Gr1j6F4UJbIYCTnIWIevJa73UjIFyT uYvjfUFfHUDUUUU X-CM-SenderInfo: purev21wro2thvvxqx5xdzvxpfor3voofrz/1tbiAgAIBF1jj365JQAAsd X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org From: Roberto Sassu Add tests to ensure that only supported dynamic pointer types are accepted, that the passed argument is actually a dynamic pointer, that the passed argument is a pointer to the stack, and that bpf_verify_pkcs7_signature() correctly handles dynamic pointers with data set to NULL. The tests are currently in the deny list for s390x (JIT does not support calling kernel function). Signed-off-by: Roberto Sassu Acked-by: Kumar Kartikeya Dwivedi --- tools/testing/selftests/bpf/DENYLIST.s390x | 1 + .../bpf/prog_tests/kfunc_dynptr_param.c | 164 ++++++++++++++++++ .../bpf/progs/test_kfunc_dynptr_param.c | 99 +++++++++++ 3 files changed, 264 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c create mode 100644 tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c diff --git a/tools/testing/selftests/bpf/DENYLIST.s390x b/tools/testing/selftests/bpf/DENYLIST.s390x index 4e305baa5277..9a6dc3671c65 100644 --- a/tools/testing/selftests/bpf/DENYLIST.s390x +++ b/tools/testing/selftests/bpf/DENYLIST.s390x @@ -71,3 +71,4 @@ cgroup_hierarchical_stats # JIT does not support calling kernel f htab_update # failed to attach: ERROR: strerror_r(-524)=22 (trampoline) lookup_key # JIT does not support calling kernel function (kfunc) verify_pkcs7_sig # JIT does not support calling kernel function (kfunc) +kfunc_dynptr_param # JIT does not support calling kernel function (kfunc) diff --git a/tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c b/tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c new file mode 100644 index 000000000000..c210657d4d0a --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/kfunc_dynptr_param.c @@ -0,0 +1,164 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Copyright (c) 2022 Facebook + * Copyright (C) 2022 Huawei Technologies Duesseldorf GmbH + * + * Author: Roberto Sassu + */ + +#include +#include "test_kfunc_dynptr_param.skel.h" + +static size_t log_buf_sz = 1048576; /* 1 MB */ +static char obj_log_buf[1048576]; + +static struct { + const char *prog_name; + const char *expected_verifier_err_msg; + int expected_runtime_err; +} kfunc_dynptr_tests[] = { + {"dynptr_type_not_supp", + "arg#0 pointer type STRUCT bpf_dynptr_kern points to unsupported dynamic pointer type", 0}, + {"not_valid_dynptr", + "arg#0 pointer type STRUCT bpf_dynptr_kern must be valid and initialized", 0}, + {"not_ptr_to_stack", "arg#0 pointer type STRUCT bpf_dynptr_kern not to stack", 0}, + {"dynptr_data_null", NULL, -EBADMSG}, +}; + +static bool kfunc_not_supported; + +static int libbpf_print_cb(enum libbpf_print_level level, const char *fmt, + va_list args) +{ + if (strcmp(fmt, "libbpf: extern (func ksym) '%s': not found in kernel or module BTFs\n")) + return 0; + + if (strcmp(va_arg(args, char *), "bpf_verify_pkcs7_signature")) + return 0; + + kfunc_not_supported = true; + return 0; +} + +static void verify_fail(const char *prog_name, const char *expected_err_msg) +{ + struct test_kfunc_dynptr_param *skel; + LIBBPF_OPTS(bpf_object_open_opts, opts); + libbpf_print_fn_t old_print_cb; + struct bpf_program *prog; + int err; + + opts.kernel_log_buf = obj_log_buf; + opts.kernel_log_size = log_buf_sz; + opts.kernel_log_level = 1; + + skel = test_kfunc_dynptr_param__open_opts(&opts); + if (!ASSERT_OK_PTR(skel, "test_kfunc_dynptr_param__open_opts")) + goto cleanup; + + prog = bpf_object__find_program_by_name(skel->obj, prog_name); + if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name")) + goto cleanup; + + bpf_program__set_autoload(prog, true); + + bpf_map__set_max_entries(skel->maps.ringbuf, getpagesize()); + + kfunc_not_supported = false; + + old_print_cb = libbpf_set_print(libbpf_print_cb); + err = test_kfunc_dynptr_param__load(skel); + libbpf_set_print(old_print_cb); + + if (err < 0 && kfunc_not_supported) { + fprintf(stderr, + "%s:SKIP:bpf_verify_pkcs7_signature() kfunc not supported\n", + __func__); + test__skip(); + goto cleanup; + } + + if (!ASSERT_ERR(err, "unexpected load success")) + goto cleanup; + + if (!ASSERT_OK_PTR(strstr(obj_log_buf, expected_err_msg), "expected_err_msg")) { + fprintf(stderr, "Expected err_msg: %s\n", expected_err_msg); + fprintf(stderr, "Verifier output: %s\n", obj_log_buf); + } + +cleanup: + test_kfunc_dynptr_param__destroy(skel); +} + +static void verify_success(const char *prog_name, int expected_runtime_err) +{ + struct test_kfunc_dynptr_param *skel; + libbpf_print_fn_t old_print_cb; + struct bpf_program *prog; + struct bpf_link *link; + __u32 next_id; + int err; + + skel = test_kfunc_dynptr_param__open(); + if (!ASSERT_OK_PTR(skel, "test_kfunc_dynptr_param__open")) + return; + + skel->bss->pid = getpid(); + + bpf_map__set_max_entries(skel->maps.ringbuf, getpagesize()); + + kfunc_not_supported = false; + + old_print_cb = libbpf_set_print(libbpf_print_cb); + err = test_kfunc_dynptr_param__load(skel); + libbpf_set_print(old_print_cb); + + if (err < 0 && kfunc_not_supported) { + fprintf(stderr, + "%s:SKIP:bpf_verify_pkcs7_signature() kfunc not supported\n", + __func__); + test__skip(); + goto cleanup; + } + + if (!ASSERT_OK(err, "test_kfunc_dynptr_param__load")) + goto cleanup; + + prog = bpf_object__find_program_by_name(skel->obj, prog_name); + if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name")) + goto cleanup; + + link = bpf_program__attach(prog); + if (!ASSERT_OK_PTR(link, "bpf_program__attach")) + goto cleanup; + + err = bpf_prog_get_next_id(0, &next_id); + + bpf_link__destroy(link); + + if (!ASSERT_OK(err, "bpf_prog_get_next_id")) + goto cleanup; + + ASSERT_EQ(skel->bss->err, expected_runtime_err, "err"); + +cleanup: + test_kfunc_dynptr_param__destroy(skel); +} + +void test_kfunc_dynptr_param(void) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(kfunc_dynptr_tests); i++) { + if (!test__start_subtest(kfunc_dynptr_tests[i].prog_name)) + continue; + + if (kfunc_dynptr_tests[i].expected_verifier_err_msg) + verify_fail(kfunc_dynptr_tests[i].prog_name, + kfunc_dynptr_tests[i].expected_verifier_err_msg); + else + verify_success(kfunc_dynptr_tests[i].prog_name, + kfunc_dynptr_tests[i].expected_runtime_err); + } +} diff --git a/tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c b/tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c new file mode 100644 index 000000000000..d7d39ea009a7 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_kfunc_dynptr_param.c @@ -0,0 +1,99 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Copyright (C) 2022 Huawei Technologies Duesseldorf GmbH + * + * Author: Roberto Sassu + */ + +#include "vmlinux.h" +#include +#include +#include + +struct bpf_dynptr { + __u64 :64; + __u64 :64; +} __attribute__((aligned(8))); + +extern struct bpf_key *bpf_lookup_system_key(__u64 id) __ksym; +extern void bpf_key_put(struct bpf_key *key) __ksym; +extern int bpf_verify_pkcs7_signature(struct bpf_dynptr *data_ptr, + struct bpf_dynptr *sig_ptr, + struct bpf_key *trusted_keyring) __ksym; + +struct { + __uint(type, BPF_MAP_TYPE_RINGBUF); +} ringbuf SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, 1); + __type(key, __u32); + __type(value, __u32); +} array_map SEC(".maps"); + +int err, pid; + +char _license[] SEC("license") = "GPL"; + +SEC("?lsm.s/bpf") +int BPF_PROG(dynptr_type_not_supp, int cmd, union bpf_attr *attr, + unsigned int size) +{ + char write_data[64] = "hello there, world!!"; + struct bpf_dynptr ptr; + + bpf_ringbuf_reserve_dynptr(&ringbuf, sizeof(write_data), 0, &ptr); + + return bpf_verify_pkcs7_signature(&ptr, &ptr, NULL); +} + +SEC("?lsm.s/bpf") +int BPF_PROG(not_valid_dynptr, int cmd, union bpf_attr *attr, unsigned int size) +{ + unsigned long val; + + return bpf_verify_pkcs7_signature((struct bpf_dynptr *)&val, + (struct bpf_dynptr *)&val, NULL); +} + +SEC("?lsm.s/bpf") +int BPF_PROG(not_ptr_to_stack, int cmd, union bpf_attr *attr, unsigned int size) +{ + unsigned long val; + + return bpf_verify_pkcs7_signature((struct bpf_dynptr *)val, + (struct bpf_dynptr *)val, NULL); +} + +SEC("lsm.s/bpf") +int BPF_PROG(dynptr_data_null, int cmd, union bpf_attr *attr, unsigned int size) +{ + struct bpf_key *trusted_keyring; + struct bpf_dynptr ptr; + __u32 *value; + int ret, zero = 0; + + if (bpf_get_current_pid_tgid() >> 32 != pid) + return 0; + + value = bpf_map_lookup_elem(&array_map, &zero); + if (!value) + return 0; + + /* Pass invalid flags. */ + ret = bpf_dynptr_from_mem(value, sizeof(*value), 1, &ptr); + if (ret != -EINVAL) + return 0; + + trusted_keyring = bpf_lookup_system_key(0); + if (!trusted_keyring) + return 0; + + err = bpf_verify_pkcs7_signature(&ptr, &ptr, trusted_keyring); + + bpf_key_put(trusted_keyring); + + return 0; +}