From patchwork Thu Dec 7 18:54:43 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 13483843 Received: from mx0b-00082601.pphosted.com (mx0b-00082601.pphosted.com [67.231.153.30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 10B841711 for ; Thu, 7 Dec 2023 10:55:20 -0800 (PST) Received: from pps.filterd (m0148460.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 3B7EKBoN011699 for ; Thu, 7 Dec 2023 10:55:19 -0800 Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3uufq6j6pr-6 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Thu, 07 Dec 2023 10:55:19 -0800 Received: from twshared2123.40.prn1.facebook.com (2620:10d:c0a8:1c::1b) by mail.thefacebook.com (2620:10d:c0a8:82::b) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.34; Thu, 7 Dec 2023 10:55:16 -0800 Received: by devbig019.vll3.facebook.com (Postfix, from userid 137359) id 4F2B53CC1CAFD; Thu, 7 Dec 2023 10:55:00 -0800 (PST) From: Andrii Nakryiko To: , , , CC: , , , , Subject: [PATCH bpf-next 8/8] selftests/bpf: add tests for BPF object load with implicit token Date: Thu, 7 Dec 2023 10:54:43 -0800 Message-ID: <20231207185443.2297160-9-andrii@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231207185443.2297160-1-andrii@kernel.org> References: <20231207185443.2297160-1-andrii@kernel.org> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-ORIG-GUID: ozydMLOqA9uNAzjaKiyTJwKjfEIkvQYL X-Proofpoint-GUID: ozydMLOqA9uNAzjaKiyTJwKjfEIkvQYL X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.997,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-12-07_15,2023-12-07_01,2023-05-22_02 Add a test to validate libbpf's implicit BPF token creation from default BPF FS location (/sys/fs/bpf). Also validate that disabling this implicit BPF token creation works. Signed-off-by: Andrii Nakryiko Acked-by: John Fastabend --- .../testing/selftests/bpf/prog_tests/token.c | 76 +++++++++++++++++++ 1 file changed, 76 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/token.c b/tools/testing/selftests/bpf/prog_tests/token.c index 9812292336c9..1a3c3aacf537 100644 --- a/tools/testing/selftests/bpf/prog_tests/token.c +++ b/tools/testing/selftests/bpf/prog_tests/token.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include "priv_map.skel.h" @@ -45,6 +46,13 @@ static inline int sys_fsmount(int fs_fd, unsigned flags, unsigned ms_flags) return syscall(__NR_fsmount, fs_fd, flags, ms_flags); } +static inline int sys_move_mount(int from_dfd, const char *from_path, + int to_dfd, const char *to_path, + unsigned flags) +{ + return syscall(__NR_move_mount, from_dfd, from_path, to_dfd, to_path, flags); +} + static int drop_priv_caps(__u64 *old_caps) { return cap_disable_effective((1ULL << CAP_BPF) | @@ -761,6 +769,63 @@ static int userns_obj_priv_btf_success(int mnt_fd) return validate_struct_ops_load(mnt_fd, true /* should succeed */); } +static int userns_obj_priv_implicit_token(int mnt_fd) +{ + LIBBPF_OPTS(bpf_object_open_opts, opts); + struct dummy_st_ops_success *skel; + int err; + + /* before we mount BPF FS with token delegation, struct_ops skeleton + * should fail to load + */ + skel = dummy_st_ops_success__open_and_load(); + if (!ASSERT_ERR_PTR(skel, "obj_tokenless_load")) { + dummy_st_ops_success__destroy(skel); + return -EINVAL; + } + + /* mount custom BPF FS over /sys/fs/bpf so that libbpf can create BPF + * token automatically and implicitly + */ + err = sys_move_mount(mnt_fd, "", AT_FDCWD, "/sys/fs/bpf", MOVE_MOUNT_F_EMPTY_PATH); + if (!ASSERT_OK(err, "move_mount_bpffs")) + return -EINVAL; + + /* now the same struct_ops skeleton should succeed thanks to libppf + * creating BPF token from /sys/fs/bpf mount point + */ + skel = dummy_st_ops_success__open_and_load(); + if (!ASSERT_OK_PTR(skel, "obj_implicit_token_load")) + return -EINVAL; + + dummy_st_ops_success__destroy(skel); + + /* now disable implicit token through empty bpf_token_path, should fail */ + opts.bpf_token_path = ""; + skel = dummy_st_ops_success__open_opts(&opts); + if (!ASSERT_OK_PTR(skel, "obj_empty_token_path_open")) + return -EINVAL; + + err = dummy_st_ops_success__load(skel); + dummy_st_ops_success__destroy(skel); + if (!ASSERT_ERR(err, "obj_empty_token_path_load")) + return -EINVAL; + + /* now disable implicit token through negative bpf_token_fd, should fail */ + opts.bpf_token_path = NULL; + opts.bpf_token_fd = -1; + skel = dummy_st_ops_success__open_opts(&opts); + if (!ASSERT_OK_PTR(skel, "obj_neg_token_fd_open")) + return -EINVAL; + + err = dummy_st_ops_success__load(skel); + dummy_st_ops_success__destroy(skel); + if (!ASSERT_ERR(err, "obj_neg_token_fd_load")) + return -EINVAL; + + return 0; +} + #define bit(n) (1ULL << (n)) void test_token(void) @@ -828,4 +893,15 @@ void test_token(void) subtest_userns(&opts, userns_obj_priv_btf_success); } + if (test__start_subtest("obj_priv_implicit_token")) { + struct bpffs_opts opts = { + /* allow BTF loading */ + .cmds = bit(BPF_BTF_LOAD) | bit(BPF_MAP_CREATE) | bit(BPF_PROG_LOAD), + .maps = bit(BPF_MAP_TYPE_STRUCT_OPS), + .progs = bit(BPF_PROG_TYPE_STRUCT_OPS), + .attachs = ~0ULL, + }; + + subtest_userns(&opts, userns_obj_priv_implicit_token); + } }