[RFC PATCH v1 5/9] selftests/landlock: Test listen on connected socket

[Mickaël Salaün]

On Sun, Jul 28, 2024 at 08:25:58AM +0800, Mikhail Ivanov wrote:
> Test checks that listen(2) doesn't wrongfully return -EACCES instead
> of -EINVAL when trying to listen for an incorrect socket state.
> 
> Signed-off-by: Mikhail Ivanov <ivanov.mikhail1 at huawei-partners.com>

Good to have this test!

> ---
>  tools/testing/selftests/landlock/net_test.c | 65 +++++++++++++++++++++
>  1 file changed, 65 insertions(+)
> 
> diff --git a/tools/testing/selftests/landlock/net_test.c b/tools/testing/selftests/landlock/net_test.c
> index b6fe9bde205f..a8385f1373f6 100644
> --- a/tools/testing/selftests/landlock/net_test.c
> +++ b/tools/testing/selftests/landlock/net_test.c
> @@ -1644,6 +1644,71 @@ TEST_F(ipv4_tcp, with_fs)
>  	EXPECT_EQ(-EACCES, bind_variant(bind_fd, &self->srv1));
>  }
>  
> +TEST_F(ipv4_tcp, listen_on_connected)

We should use the "protocol" fixture and its variants instead to test
with different protocols and also without sandboxing (which is crutial).

I guess espintcp_listen should use "protocol" too.

ipv4_tcp is to run tests that only make sense on an IPv4 socket, but
when we test EINVAL, we should make sure Landlock doesn't introduce
inconsistencies for other/unsupported protocols.

> +{
> +	const struct landlock_ruleset_attr ruleset_attr = {
> +		.handled_access_net = ACCESS_ALL,
> +	};
> +	const struct landlock_net_port_attr tcp_not_restricted_p0 = {
> +		.allowed_access = ACCESS_ALL,
> +		.port = self->srv0.port,
> +	};
> +	const struct landlock_net_port_attr tcp_denied_listen_p1 = {
> +		.allowed_access = ACCESS_ALL & ~LANDLOCK_ACCESS_NET_LISTEN_TCP,
> +		.port = self->srv1.port,
> +	};
> +	int ruleset_fd;
> +	int bind_fd, status;
> +	pid_t child;
> +
> +	ruleset_fd =
> +		landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
> +	ASSERT_LE(0, ruleset_fd);
> +
> +	/* Allows all actions for the first port. */
> +	ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_NET_PORT,
> +				       &tcp_not_restricted_p0, 0));
> +
> +	/* Deny listen for the second port. */

nit: Denies listening

> +	ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_NET_PORT,
> +				       &tcp_denied_listen_p1, 0));
> +
> +	enforce_ruleset(_metadata, ruleset_fd);
> +	EXPECT_EQ(0, close(ruleset_fd));
> +
> +	/* Init listening socket. */

nit: Initializes

> +	bind_fd = socket_variant(&self->srv0);
> +	ASSERT_LE(0, bind_fd);
> +	EXPECT_EQ(0, bind_variant(bind_fd, &self->srv0));
> +	EXPECT_EQ(0, listen_variant(bind_fd, backlog));
> +
> +	child = fork();
> +	ASSERT_LE(0, child);
> +	if (child == 0) {
> +		int connect_fd;
> +
> +		/* Closes listening socket for the child. */
> +		EXPECT_EQ(0, close(bind_fd));
> +
> +		connect_fd = socket_variant(&self->srv1);
> +		ASSERT_LE(0, connect_fd);
> +		EXPECT_EQ(0, connect_variant(connect_fd, &self->srv0));
> +
> +		/* Tries to listen on connected socket. */
> +		EXPECT_EQ(-EINVAL, listen_variant(connect_fd, backlog));
> +
> +		EXPECT_EQ(0, close(connect_fd));
> +		_exit(_metadata->exit_code);
> +		return;
> +	}
> +
> +	EXPECT_EQ(child, waitpid(child, &status, 0));
> +	EXPECT_EQ(1, WIFEXITED(status));
> +	EXPECT_EQ(EXIT_SUCCESS, WEXITSTATUS(status));
> +
> +	EXPECT_EQ(0, close(bind_fd));
> +}
> +
>  FIXTURE(port_specific)
>  {
>  	struct service_fixture srv0;
> -- 
> 2.34.1
> 
>