[RFC PATCH v4 10/15] seltest/landlock: add tests for bind() hooks

[Konstantin Meskhidze]

Adds two selftests for bind socket action.
The one is with no landlock restrictions:
    - bind_no_restrictions;
The second one is with mixed landlock rules:
    - bind_with_restrictions;

Signed-off-by: Konstantin Meskhidze <konstantin.meskhidze at huawei.com>
---

Changes since v3:
* Split commit.
* Add helper create_socket.
* Add FIXTURE_SETUP.

---
 .../testing/selftests/landlock/network_test.c | 153 ++++++++++++++++++
 1 file changed, 153 insertions(+)
 create mode 100644 tools/testing/selftests/landlock/network_test.c

diff --git a/tools/testing/selftests/landlock/network_test.c b/tools/testing/selftests/landlock/network_test.c
new file mode 100644
index 000000000000..4c60f6d973a8
--- /dev/null
+++ b/tools/testing/selftests/landlock/network_test.c
@@ -0,0 +1,153 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Landlock tests - Network
+ *
+ * Copyright (C) 2022 Huawei Tech. Co., Ltd.
+ * Author: Konstantin Meskhidze <konstantin.meskhidze at huawei.com>
+ *
+ */
+
+#define _GNU_SOURCE
+#include <arpa/inet.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/landlock.h>
+#include <netinet/in.h>
+#include <string.h>
+#include <sys/prctl.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+
+#include "common.h"
+
+#define MAX_SOCKET_NUM 10
+
+#define SOCK_PORT_START 3470
+#define SOCK_PORT_ADD 10
+
+#define IP_ADDRESS "127.0.0.1"
+
+uint port[MAX_SOCKET_NUM];
+struct sockaddr_in addr[MAX_SOCKET_NUM];
+
+const int one = 1;
+
+/* Number pending connections queue to be hold */
+#define BACKLOG 10
+
+static int create_socket(struct __test_metadata *const _metadata)
+{
+
+		int sockfd;
+
+		sockfd = socket(AF_INET, SOCK_STREAM | SOCK_CLOEXEC, 0);
+		ASSERT_LE(0, sockfd);
+		/* Allows to reuse of local address */
+		ASSERT_EQ(0, setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)));
+
+		return sockfd;
+}
+
+static void enforce_ruleset(struct __test_metadata *const _metadata,
+		const int ruleset_fd)
+{
+	ASSERT_EQ(0, prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0));
+	ASSERT_EQ(0, landlock_restrict_self(ruleset_fd, 0)) {
+		TH_LOG("Failed to enforce ruleset: %s", strerror(errno));
+	}
+}
+
+FIXTURE(socket) { };
+
+FIXTURE_SETUP(socket)
+{
+	int i;
+	/* Creates socket addresses */
+	for (i = 0; i < MAX_SOCKET_NUM; i++) {
+		port[i] = SOCK_PORT_START + SOCK_PORT_ADD*i;
+		addr[i].sin_family = AF_INET;
+		addr[i].sin_port = htons(port[i]);
+		addr[i].sin_addr.s_addr = inet_addr(IP_ADDRESS);
+		memset(&(addr[i].sin_zero), '\0', 8);
+	}
+}
+
+FIXTURE_TEARDOWN(socket)
+{ }
+
+TEST_F_FORK(socket, bind_no_restrictions) {
+
+	int sockfd;
+
+	sockfd = create_socket(_metadata);
+	ASSERT_LE(0, sockfd);
+
+	/* Binds a socket to port[0] */
+	ASSERT_EQ(0, bind(sockfd, (struct sockaddr *)&addr[0], sizeof(addr[0])));
+
+	ASSERT_EQ(0, close(sockfd));
+}
+
+TEST_F_FORK(socket, bind_with_restrictions) {
+
+	int sockfd_1, sockfd_2, sockfd_3;
+
+	struct landlock_ruleset_attr ruleset_attr = {
+		.handled_access_net = LANDLOCK_ACCESS_NET_BIND_TCP |
+				      LANDLOCK_ACCESS_NET_CONNECT_TCP,
+	};
+	struct landlock_net_service_attr net_service_1 = {
+		.allowed_access = LANDLOCK_ACCESS_NET_BIND_TCP |
+				  LANDLOCK_ACCESS_NET_CONNECT_TCP,
+		.port = port[0],
+	};
+	struct landlock_net_service_attr net_service_2 = {
+		.allowed_access = LANDLOCK_ACCESS_NET_CONNECT_TCP,
+		.port = port[1],
+	};
+	struct landlock_net_service_attr net_service_3 = {
+		.allowed_access = 0,
+		.port = port[2],
+	};
+
+	const int ruleset_fd = landlock_create_ruleset(&ruleset_attr,
+			sizeof(ruleset_attr), 0);
+	ASSERT_LE(0, ruleset_fd);
+
+	/* Allows connect and bind operations to the port[0] socket. */
+	ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_NET_SERVICE,
+				&net_service_1, 0));
+	/* Allows connect and deny bind operations to the port[1] socket. */
+	ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_NET_SERVICE,
+				&net_service_2, 0));
+	/* Empty allowed_access (i.e. deny rules) are ignored in network actions
+	 * for port[2] socket.
+	 */
+	ASSERT_EQ(-1, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_NET_SERVICE,
+				&net_service_3, 0));
+	ASSERT_EQ(ENOMSG, errno);
+
+	/* Enforces the ruleset. */
+	enforce_ruleset(_metadata, ruleset_fd);
+
+	sockfd_1 = create_socket(_metadata);
+	ASSERT_LE(0, sockfd_1);
+	/* Binds a socket to port[0] */
+	ASSERT_EQ(0, bind(sockfd_1, (struct sockaddr  *)&addr[0], sizeof(addr[0])));
+
+	/* Close bounded socket*/
+	ASSERT_EQ(0, close(sockfd_1));
+
+	sockfd_2 = create_socket(_metadata);
+	ASSERT_LE(0, sockfd_2);
+	/* Binds a socket to port[1] */
+	ASSERT_EQ(-1, bind(sockfd_2, (struct sockaddr *)&addr[1], sizeof(addr[1])));
+	ASSERT_EQ(EACCES, errno);
+
+	sockfd_3 = create_socket(_metadata);
+	ASSERT_LE(0, sockfd_3);
+	/* Binds a socket to port[2] */
+	ASSERT_EQ(-1, bind(sockfd_3, (struct sockaddr *)&addr[2], sizeof(addr[2])));
+	ASSERT_EQ(EACCES, errno);
+}
+TEST_HARNESS_MAIN
--
2.25.1