[PATCH v2 bpf-next 09/18] selftests/bpf: add BPF token-enabled test for BPF_MAP_CREATE command

Andrii Nakryiko
2023-06-07T23:54:17Z

Add test for creating BPF token with support for BPF_MAP_CREATE
delegation. And validate that its allowed_map_types filter works as
expected and allows to create privileged BPF maps through delegated
token, as long as they are allowed by privileged creator of a token.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
.../testing/selftests/bpf/prog_tests/token.c | 50 +++++++++++++++++++
1 file changed, 50 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/token.c b/tools/testing/selftests/bpf/prog_tests/token.c
index cba84c480ac5..61707b3e81a7 100644
--- a/tools/testing/selftests/bpf/prog_tests/token.c
+++ b/tools/testing/selftests/bpf/prog_tests/token.c
@@ -86,8 +86,58 @@ static void subtest_token_create(void)
ASSERT_OK(restore_priv_caps(old_caps), "restore_caps");
}

+static void subtest_map_token(void)
+{
+ LIBBPF_OPTS(bpf_token_create_opts, token_opts);
+ LIBBPF_OPTS(bpf_map_create_opts, map_opts);
+ int token_fd = 0, map_fd = 0;
+ __u64 old_caps = 0;
+
+ /* check that it's ok to allow any map type */
+ token_opts.allowed_map_types = ~0ULL; /* any current and future map types is allowed */
+ token_fd = bpf_token_create(&token_opts);
+ if (!ASSERT_GT(token_fd, 0, "token_create_future_proof"))
+ return;
+ close(token_fd);
+
+ /* create BPF token allowing STACK, but not QUEUE map */
+ token_opts.allowed_cmds = 1ULL << BPF_MAP_CREATE;
+ token_opts.allowed_map_types = 1ULL << BPF_MAP_TYPE_STACK; /* but not QUEUE */
+ 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;
+
+ /* BPF_MAP_TYPE_STACK is privileged, but with given token_fd should succeed */
+ map_opts.token_fd = token_fd;
+ map_fd = bpf_map_create(BPF_MAP_TYPE_STACK, "token_stack", 0, 8, 1, &map_opts);
+ if (!ASSERT_GT(map_fd, 0, "stack_map_fd"))
+ goto cleanup;
+ close(map_fd);
+ map_fd = 0;
+
+ /* BPF_MAP_TYPE_QUEUE is privileged, and token doesn't allow it, so should fail */
+ map_opts.token_fd = token_fd;
+ map_fd = bpf_map_create(BPF_MAP_TYPE_QUEUE, "token_queue", 0, 8, 1, &map_opts);
+ if (!ASSERT_EQ(map_fd, -EPERM, "queue_map_fd"))
+ goto cleanup;
+
+cleanup:
+ if (map_fd > 0)
+ close(map_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();
}
--
2.34.1