From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0a-00082601.pphosted.com (mx0b-00082601.pphosted.com [67.231.153.30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 877AC128 for ; Wed, 13 Dec 2023 11:09:44 -0800 (PST) Received: from pps.filterd (m0089730.ppops.net [127.0.0.1]) by m0089730.ppops.net (8.17.1.19/8.17.1.19) with ESMTP id 3BDIXTj0026104 for ; Wed, 13 Dec 2023 11:09:43 -0800 Received: from mail.thefacebook.com ([163.114.132.120]) by m0089730.ppops.net (PPS) with ESMTPS id 3uxq0kaw60-10 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Wed, 13 Dec 2023 11:09:43 -0800 Received: from twshared29647.38.frc1.facebook.com (2620:10d:c085:208::f) by mail.thefacebook.com (2620:10d:c085:21d::8) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.34; Wed, 13 Dec 2023 11:09:36 -0800 Received: by devbig019.vll3.facebook.com (Postfix, from userid 137359) id 7AFCC3D185B81; Wed, 13 Dec 2023 11:09:32 -0800 (PST) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH v3 bpf-next 10/10] selftests/bpf: add tests for LIBBPF_BPF_TOKEN_PATH envvar Date: Wed, 13 Dec 2023 11:08:42 -0800 Message-ID: <20231213190842.3844987-11-andrii@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231213190842.3844987-1-andrii@kernel.org> References: <20231213190842.3844987-1-andrii@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-FB-Internal: Safe Content-Type: text/plain X-Proofpoint-GUID: 5l9lM0rCINLoqEB58glkiJpxRmyUq-mq X-Proofpoint-ORIG-GUID: 5l9lM0rCINLoqEB58glkiJpxRmyUq-mq 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=2023-12-13_12,2023-12-13_01,2023-05-22_02 Add new subtest validating LIBBPF_BPF_TOKEN_PATH envvar semantics. Extend existing test to validate that LIBBPF_BPF_TOKEN_PATH allows to disable implicit BPF token creation by setting envvar to empty string. Signed-off-by: Andrii Nakryiko --- .../testing/selftests/bpf/prog_tests/token.c | 112 ++++++++++++++++++ 1 file changed, 112 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/token.c b/tools/testi= ng/selftests/bpf/prog_tests/token.c index 1a3c3aacf537..548aeb91ab0d 100644 --- a/tools/testing/selftests/bpf/prog_tests/token.c +++ b/tools/testing/selftests/bpf/prog_tests/token.c @@ -769,6 +769,9 @@ static int userns_obj_priv_btf_success(int mnt_fd) return validate_struct_ops_load(mnt_fd, true /* should succeed */); } =20 +#define TOKEN_ENVVAR "LIBBPF_BPF_TOKEN_PATH" +#define TOKEN_BPFFS_CUSTOM "/bpf-token-fs" + static int userns_obj_priv_implicit_token(int mnt_fd) { LIBBPF_OPTS(bpf_object_open_opts, opts); @@ -791,6 +794,20 @@ static int userns_obj_priv_implicit_token(int mnt_fd= ) if (!ASSERT_OK(err, "move_mount_bpffs")) return -EINVAL; =20 + /* disable implicit BPF token creation by setting + * LIBBPF_BPF_TOKEN_PATH envvar to empty value, load should fail + */ + err =3D setenv(TOKEN_ENVVAR, "", 1 /*overwrite*/); + if (!ASSERT_OK(err, "setenv_token_path")) + return -EINVAL; + skel =3D dummy_st_ops_success__open_and_load(); + if (!ASSERT_ERR_PTR(skel, "obj_token_envvar_disabled_load")) { + unsetenv(TOKEN_ENVVAR); + dummy_st_ops_success__destroy(skel); + return -EINVAL; + } + unsetenv(TOKEN_ENVVAR); + /* now the same struct_ops skeleton should succeed thanks to libppf * creating BPF token from /sys/fs/bpf mount point */ @@ -826,6 +843,90 @@ static int userns_obj_priv_implicit_token(int mnt_fd= ) return 0; } =20 +static int userns_obj_priv_implicit_token_envvar(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 =3D 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 custom location, so libbpf can't create + * BPF token implicitly, unless pointed to it through + * LIBBPF_BPF_TOKEN_PATH envvar + */ + rmdir(TOKEN_BPFFS_CUSTOM); + if (!ASSERT_OK(mkdir(TOKEN_BPFFS_CUSTOM, 0777), "mkdir_bpffs_custom")) + goto err_out; + err =3D sys_move_mount(mnt_fd, "", AT_FDCWD, TOKEN_BPFFS_CUSTOM, MOVE_M= OUNT_F_EMPTY_PATH); + if (!ASSERT_OK(err, "move_mount_bpffs")) + goto err_out; + + /* even though we have BPF FS with delegation, it's not at default + * /sys/fs/bpf location, so we still fail to load until envvar is set u= p + */ + skel =3D dummy_st_ops_success__open_and_load(); + if (!ASSERT_ERR_PTR(skel, "obj_tokenless_load2")) { + dummy_st_ops_success__destroy(skel); + goto err_out; + } + + err =3D setenv(TOKEN_ENVVAR, TOKEN_BPFFS_CUSTOM, 1 /*overwrite*/); + if (!ASSERT_OK(err, "setenv_token_path")) + goto err_out; + + /* now the same struct_ops skeleton should succeed thanks to libppf + * creating BPF token from custom mount point + */ + skel =3D dummy_st_ops_success__open_and_load(); + if (!ASSERT_OK_PTR(skel, "obj_implicit_token_load")) + goto err_out; + + dummy_st_ops_success__destroy(skel); + + /* now disable implicit token through empty bpf_token_path, envvar + * will be ignored, should fail + */ + opts.bpf_token_path =3D ""; + skel =3D dummy_st_ops_success__open_opts(&opts); + if (!ASSERT_OK_PTR(skel, "obj_empty_token_path_open")) + goto err_out; + + err =3D dummy_st_ops_success__load(skel); + dummy_st_ops_success__destroy(skel); + if (!ASSERT_ERR(err, "obj_empty_token_path_load")) + goto err_out; + + /* now disable implicit token through negative bpf_token_fd, envvar + * will be ignored, should fail + */ + opts.bpf_token_path =3D NULL; + opts.bpf_token_fd =3D -1; + skel =3D dummy_st_ops_success__open_opts(&opts); + if (!ASSERT_OK_PTR(skel, "obj_neg_token_fd_open")) + goto err_out; + + err =3D dummy_st_ops_success__load(skel); + dummy_st_ops_success__destroy(skel); + if (!ASSERT_ERR(err, "obj_neg_token_fd_load")) + goto err_out; + + rmdir(TOKEN_BPFFS_CUSTOM); + unsetenv(TOKEN_ENVVAR); + return 0; +err_out: + rmdir(TOKEN_BPFFS_CUSTOM); + unsetenv(TOKEN_ENVVAR); + return -EINVAL; +} + #define bit(n) (1ULL << (n)) =20 void test_token(void) @@ -904,4 +1005,15 @@ void test_token(void) =20 subtest_userns(&opts, userns_obj_priv_implicit_token); } + if (test__start_subtest("obj_priv_implicit_token_envvar")) { + struct bpffs_opts opts =3D { + /* allow BTF loading */ + .cmds =3D bit(BPF_BTF_LOAD) | bit(BPF_MAP_CREATE) | bit(BPF_PROG_LOAD= ), + .maps =3D bit(BPF_MAP_TYPE_STRUCT_OPS), + .progs =3D bit(BPF_PROG_TYPE_STRUCT_OPS), + .attachs =3D ~0ULL, + }; + + subtest_userns(&opts, userns_obj_priv_implicit_token_envvar); + } } --=20 2.34.1