From: Martin KaFai Lau <kafai@fb.com>
To: Stanislav Fomichev <sdf@google.com>
Cc: <netdev@vger.kernel.org>, <bpf@vger.kernel.org>, <ast@kernel.org>,
<daniel@iogearbox.net>, Andrey Ignatov <rdna@fb.com>
Subject: Re: [PATCH bpf-next v3 2/2] selftests/bpf: verify that rebinding to port < 1024 from BPF works
Date: Tue, 26 Jan 2021 10:18:38 -0800 [thread overview]
Message-ID: <20210126181838.boof6nddaazjrfng@kafai-mbp> (raw)
In-Reply-To: <20210126165104.891536-2-sdf@google.com>
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.
next prev parent reply other threads:[~2021-01-27 10:11 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-26 16:51 [PATCH bpf-next v3 1/2] bpf: allow rewriting to ports under ip_unprivileged_port_start Stanislav Fomichev
2021-01-26 16:51 ` [PATCH bpf-next v3 2/2] selftests/bpf: verify that rebinding to port < 1024 from BPF works Stanislav Fomichev
2021-01-26 18:18 ` Martin KaFai Lau [this message]
2021-01-26 19:04 ` Stanislav Fomichev
2021-01-26 18:01 ` [PATCH bpf-next v3 1/2] bpf: allow rewriting to ports under ip_unprivileged_port_start Martin KaFai Lau
2021-01-26 18:05 ` Stanislav Fomichev
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