On Tue, Jan 26, 2021 at 08:51:04AM -0800, Stanislav Fomichev wrote:
> Return 3 to indicate that permission check for port 111
> should be skipped.
>
[ ... ]
> +void cap_net_bind_service(cap_flag_value_t flag)
> +{
> + const cap_value_t cap_net_bind_service = CAP_NET_BIND_SERVICE;
> + cap_t caps;
> +
> + caps = cap_get_proc();
> + if (CHECK(!caps, "cap_get_proc", "errno %d", errno))
> + goto free_caps;
> +
> + if (CHECK(cap_set_flag(caps, CAP_EFFECTIVE, 1, &cap_net_bind_service,
> + flag),
> + "cap_set_flag", "errno %d", errno))
> + goto free_caps;
> +
> + if (CHECK(cap_set_proc(caps), "cap_set_proc", "errno %d", errno))
> + goto free_caps;
> +
> +free_caps:
> + if (CHECK(cap_free(caps), "cap_free", "errno %d", errno))
> + goto free_caps;
Also mentioned in v2, there is a loop.
> +}
> +
> +void test_bind_perm(void)
> +{
> + struct bind_perm *skel;
> + int cgroup_fd;
> +
> + cgroup_fd = test__join_cgroup("/bind_perm");
> + if (CHECK(cgroup_fd < 0, "cg-join", "errno %d", errno))
> + return;
> +
> + skel = bind_perm__open_and_load();
> + if (!ASSERT_OK_PTR(skel, "skel"))
> + goto close_cgroup_fd;
> +
> + skel->links.bind_v4_prog = bpf_program__attach_cgroup(skel->progs.bind_v4_prog, cgroup_fd);
> + if (!ASSERT_OK_PTR(skel, "bind_v4_prog"))
> + goto close_skeleton;
> +
> + cap_net_bind_service(CAP_CLEAR);
> + try_bind(110, EACCES);
> + try_bind(111, 0);
> + cap_net_bind_service(CAP_SET);
Instead of always CAP_SET at the end of the test,
it is better to do a cap_get_flag() to save the original value
at the beginning of the test and restore it at the end
of the test.
