[PATCH v2 bpf-next 12/18] selftests/bpf: add BPF token-enabled BPF_BTF_LOAD selftest
From: Andrii Nakryiko <andrii@kernel.org>
Date: 2023-06-07 23:54:30
Also in:
bpf
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [selftests] (test runners & infrastructure), kernel selftest framework, the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Shuah Khan, Linus Torvalds
Add a simple test validating that BTF loading can be done from unprivileged process through delegated BPF token. Signed-off-by: Andrii Nakryiko <andrii@kernel.org> --- .../testing/selftests/bpf/prog_tests/token.c | 55 +++++++++++++++++++ 1 file changed, 55 insertions(+)
diff --git a/tools/testing/selftests/bpf/prog_tests/token.c b/tools/testing/selftests/bpf/prog_tests/token.c
index 61707b3e81a7..ff8ada405576 100644
--- a/tools/testing/selftests/bpf/prog_tests/token.c
+++ b/tools/testing/selftests/bpf/prog_tests/token.c@@ -134,10 +134,65 @@ static void subtest_map_token(void) ASSERT_OK(restore_priv_caps(old_caps), "restore_caps"); } +static void subtest_btf_token(void) +{ + LIBBPF_OPTS(bpf_token_create_opts, token_opts); + LIBBPF_OPTS(bpf_btf_load_opts, btf_opts); + int token_fd = 0, btf_fd = 0; + const void *raw_btf_data; + struct btf *btf = NULL; + __u32 raw_btf_size; + __u64 old_caps = 0; + + /* create BPF token allowing BPF_BTF_LOAD command */ + token_opts.allowed_cmds = 1ULL << BPF_BTF_LOAD; + token_fd = bpf_token_create(&token_opts); + if (!ASSERT_GT(token_fd, 0, "token_create")) + return; + + /* drop privileges to test token_fd passing */ + if (!ASSERT_OK(drop_priv_caps(&old_caps), "drop_caps")) + goto cleanup; + + btf = btf__new_empty(); + if (!ASSERT_OK_PTR(btf, "empty_btf")) + goto cleanup; + + ASSERT_GT(btf__add_int(btf, "int", 4, 0), 0, "int_type"); + + raw_btf_data = btf__raw_data(btf, &raw_btf_size); + if (!ASSERT_OK_PTR(raw_btf_data, "raw_btf_data")) + goto cleanup; + + /* validate we can successfully load new BTF with token */ + btf_opts.token_fd = token_fd; + btf_fd = bpf_btf_load(raw_btf_data, raw_btf_size, &btf_opts); + if (!ASSERT_GT(btf_fd, 0, "btf_fd")) + goto cleanup; + close(btf_fd); + + /* now validate that we *cannot* load BTF without token */ + btf_opts.token_fd = 0; + btf_fd = bpf_btf_load(raw_btf_data, raw_btf_size, &btf_opts); + if (!ASSERT_EQ(btf_fd, -EPERM, "btf_fd_eperm")) + goto cleanup; + +cleanup: + btf__free(btf); + if (btf_fd > 0) + close(btf_fd); + if (token_fd) + close(token_fd); + if (old_caps) + ASSERT_OK(restore_priv_caps(old_caps), "restore_caps"); +} + void test_token(void) { if (test__start_subtest("token_create")) subtest_token_create(); if (test__start_subtest("map_token")) subtest_map_token(); + if (test__start_subtest("btf_token")) + subtest_btf_token(); }
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2.34.1