On Wed, Aug 14, 2024 at 11:01:50AM +0800, Mikhail Ivanov wrote:
> listen(2) can be used to change length of the pending connections queue
> of the listening socket. Such scenario shouldn't be restricted by Landlock
> since socket doesn't change its state.
Yes, this behavior makes sense to me as well. 👍 __inet_listen_sk()
only changes sk->sk_max_ack_backlog when listen() gets called a second
time.
> * Implement test that validates this case.
>
> Signed-off-by: Mikhail Ivanov <ivanov.mikhail1@xxxxxxxxxxxxxxxxxxx>
> ---
> tools/testing/selftests/landlock/net_test.c | 26 +++++++++++++++++++++
> 1 file changed, 26 insertions(+)
>
> diff --git a/tools/testing/selftests/landlock/net_test.c b/tools/testing/selftests/landlock/net_test.c
> index 6831d8a2e9aa..dafc433a0068 100644
> --- a/tools/testing/selftests/landlock/net_test.c
> +++ b/tools/testing/selftests/landlock/net_test.c
> @@ -1768,6 +1768,32 @@ TEST_F(ipv4_tcp, with_fs)
> EXPECT_EQ(-EACCES, bind_variant(bind_fd, &self->srv1));
> }
>
> +TEST_F(ipv4_tcp, double_listen)
> +{
> + const struct landlock_ruleset_attr ruleset_attr = {
> + .handled_access_net = LANDLOCK_ACCESS_NET_LISTEN_TCP,
> + };
> + int ruleset_fd;
> + int listen_fd;
> +
> + listen_fd = socket_variant(&self->srv0);
> + ASSERT_LE(0, listen_fd);
> +
> + EXPECT_EQ(0, bind_variant(listen_fd, &self->srv0));
> + EXPECT_EQ(0, listen_variant(listen_fd, backlog));
> +
> + ruleset_fd =
> + landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
> + ASSERT_LE(0, ruleset_fd);
> +
> + /* Denies listen. */
> + enforce_ruleset(_metadata, ruleset_fd);
> + EXPECT_EQ(0, close(ruleset_fd));
> +
> + /* Tries to change backlog value of listening socket. */
> + EXPECT_EQ(0, listen_variant(listen_fd, backlog + 1));
For test clarity: Without reading the commit message, I believe it
might not be obvious to the reader *why* the second listen() is
supposed to work. This might be worth a comment.
> +}
> +
> FIXTURE(port_specific)
> {
> struct service_fixture srv0;
> --
> 2.34.1
>
Reviewed-by: Günther Noack <gnoack3000@xxxxxxxxx>
