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

[Mikhail Ivanov]

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>
---
 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)
+{
+	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. */
+	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. */
+	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