netdev - Re: [RFC PATCH v2 6/9] selftests/landlock: Test listening without explicit bind restriction

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Message-ID: <4aae6528-cfed-efc5-a7bc-d967a8d43153@huawei-partners.com>
Date: Wed, 21 Aug 2024 14:52:34 +0300
From: Mikhail Ivanov <ivanov.mikhail1@...wei-partners.com>
To: Günther Noack <gnoack@...gle.com>
CC: <mic@...ikod.net>, <willemdebruijn.kernel@...il.com>,
	<gnoack3000@...il.com>, <linux-security-module@...r.kernel.org>,
	<netdev@...r.kernel.org>, <netfilter-devel@...r.kernel.org>,
	<yusongping@...wei.com>, <artem.kuzin@...wei.com>,
	<konstantin.meskhidze@...wei.com>
Subject: Re: [RFC PATCH v2 6/9] selftests/landlock: Test listening without
 explicit bind restriction

8/20/2024 4:46 PM, Mikhail Ivanov wrote:
> 8/20/2024 4:02 PM, Günther Noack wrote:
>> On Wed, Aug 14, 2024 at 11:01:48AM +0800, Mikhail Ivanov wrote:
>>> Test scenarios where listen(2) call without explicit bind(2) is allowed
>>> and forbidden.
>>>
>>> Signed-off-by: Mikhail Ivanov <ivanov.mikhail1@...wei-partners.com>
>>> ---
>>>   tools/testing/selftests/landlock/net_test.c | 83 +++++++++++++++++++++
>>>   1 file changed, 83 insertions(+)
>>>
>>> diff --git a/tools/testing/selftests/landlock/net_test.c 
>>> b/tools/testing/selftests/landlock/net_test.c
>>> index 551891b18b7a..92c042349596 100644
>>> --- a/tools/testing/selftests/landlock/net_test.c
>>> +++ b/tools/testing/selftests/landlock/net_test.c
>>> @@ -1851,6 +1851,89 @@ TEST_F(port_specific, bind_connect_zero)
>>>       EXPECT_EQ(0, close(bind_fd));
>>>   }
>>> +TEST_F(port_specific, listen_without_bind_allowed)
>>> +{
>>> +    if (variant->sandbox == TCP_SANDBOX) {
>>> +        const struct landlock_ruleset_attr ruleset_attr = {
>>> +            .handled_access_net = LANDLOCK_ACCESS_NET_BIND_TCP |
>>> +                          LANDLOCK_ACCESS_NET_LISTEN_TCP
>>> +        };
>>> +        const struct landlock_net_port_attr tcp_listen_zero = {
>>> +            .allowed_access = LANDLOCK_ACCESS_NET_LISTEN_TCP,
>>> +            .port = 0,
>>> +        };
>>> +        int ruleset_fd;
>>> +
>>> +        ruleset_fd = landlock_create_ruleset(&ruleset_attr,
>>> +                             sizeof(ruleset_attr), 0);
>>> +        ASSERT_LE(0, ruleset_fd);
>>> +
>>> +        /*
>>> +         * Allow listening without explicit bind
>>> +         * (cf. landlock_net_port_attr).
>>> +         */
>>> +        EXPECT_EQ(0,
>>> +              landlock_add_rule(ruleset_fd, LANDLOCK_RULE_NET_PORT,
>>> +                        &tcp_listen_zero, 0));
>>> +
>>> +        enforce_ruleset(_metadata, ruleset_fd);
>>> +        EXPECT_EQ(0, close(ruleset_fd));
>>> +    }
>>> +    int listen_fd, connect_fd;
>>> +    __u64 port;
>>> +
>>> +    listen_fd = socket_variant(&self->srv0);
>>> +    ASSERT_LE(0, listen_fd);
>>> +
>>> +    connect_fd = socket_variant(&self->srv0);
>>> +    ASSERT_LE(0, connect_fd);
>>> +    /*
>>> +     * Allow listen(2) to select a random port for the socket,
>>> +     * since bind(2) wasn't called.
>>> +     */
>>> +    EXPECT_EQ(0, listen_variant(listen_fd, backlog));
>>> +
>>> +    /* Connects on the binded port. */
>>> +    port = get_binded_port(listen_fd, &variant->prot);
>>
>> Please rename "binded" to "bound" when you come across it.
> 
> Can I do such refactoring in the 3/9 patch?

I mean, can I replace all "binded" occurrences in net_test in 3/9 patch?

> 
>>
>>
>>> +    EXPECT_NE(0, port);
>>> +    set_port(&self->srv0, port);
>>> +    EXPECT_EQ(0, connect_variant(connect_fd, &self->srv0));
>>> +
>>> +    EXPECT_EQ(0, close(connect_fd));
>>> +    EXPECT_EQ(0, close(listen_fd));
>>> +}
>>> +
>>> +TEST_F(port_specific, listen_without_bind_denied)
>>> +{
>>> +    if (variant->sandbox == TCP_SANDBOX) {
>>> +        const struct landlock_ruleset_attr ruleset_attr = {
>>> +            .handled_access_net = LANDLOCK_ACCESS_NET_LISTEN_TCP
>>> +        };
>>> +        int ruleset_fd;
>>> +
>>> +        ruleset_fd = landlock_create_ruleset(&ruleset_attr,
>>> +                             sizeof(ruleset_attr), 0);
>>> +        ASSERT_LE(0, ruleset_fd);
>>> +
>>> +        /* Deny listening. */
>>> +        enforce_ruleset(_metadata, ruleset_fd);
>>> +        EXPECT_EQ(0, close(ruleset_fd));
>>> +    }
>>> +    int listen_fd, ret;
>>> +
>>> +    listen_fd = socket_variant(&self->srv0);
>>> +    ASSERT_LE(0, listen_fd);
>>> +
>>> +    /* Checks that listening without explicit binding is prohibited. */
>>> +    ret = listen_variant(listen_fd, backlog);
>>> +    if (is_restricted(&variant->prot, variant->sandbox)) {
>>> +        /* Denied by Landlock. */
>>> +        EXPECT_EQ(-EACCES, ret);
>>> +    } else {
>>> +        EXPECT_EQ(0, ret);
>>> +    }
>>> +}
>>> +
>>>   TEST_F(port_specific, port_1023)
>>>   {
>>>       int bind_fd, connect_fd, ret;
>>> -- 
>>> 2.34.1
>>>