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.
* 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));
+}
+
FIXTURE(port_specific)
{
struct service_fixture srv0;
--
2.34.1
