[RFC PATCH v2 03/12] selftests/landlock: Add protocol.create to socket tests

[Mikhail Ivanov]

Initiate socket_test.c selftests. Add protocol fixture for tests
with changeable family-type values. Only most common variants of
protocols (like ipv4-tcp,ipv6-udp, unix) were added.
Add simple socket access right checking test.

Signed-off-by: Mikhail Ivanov <ivanov.mikhail1 at huawei-partners.com>
---

Changes since v1:
* Replaces test_socket_create() and socket_variant() helpers
  with test_socket().
* Renames domain to family in protocol fixture.
* Remove AF_UNSPEC fixture entry and add unspec_srv0 fixture field to
  check AF_UNSPEC socket creation case.
* Formats code with clang-format.
* Refactors commit message.
---
 .../testing/selftests/landlock/socket_test.c  | 181 ++++++++++++++++++
 1 file changed, 181 insertions(+)
 create mode 100644 tools/testing/selftests/landlock/socket_test.c

diff --git a/tools/testing/selftests/landlock/socket_test.c b/tools/testing/selftests/landlock/socket_test.c
new file mode 100644
index 000000000000..4c51f89ed578
--- /dev/null
+++ b/tools/testing/selftests/landlock/socket_test.c
@@ -0,0 +1,181 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Landlock tests - Socket
+ *
+ * Copyright © 2024 Huawei Tech. Co., Ltd.
+ * Copyright © 2024 Microsoft Corporation
+ */
+
+#define _GNU_SOURCE
+
+#include <errno.h>
+#include <linux/landlock.h>
+#include <sched.h>
+#include <string.h>
+#include <sys/prctl.h>
+#include <sys/socket.h>
+
+#include "common.h"
+
+/* clang-format off */
+
+#define ACCESS_LAST LANDLOCK_ACCESS_SOCKET_CREATE
+
+#define ACCESS_ALL ( \
+	LANDLOCK_ACCESS_SOCKET_CREATE)
+
+/* clang-format on */
+
+struct protocol_variant {
+	int family;
+	int type;
+};
+
+struct service_fixture {
+	struct protocol_variant protocol;
+};
+
+static void setup_namespace(struct __test_metadata *const _metadata)
+{
+	set_cap(_metadata, CAP_SYS_ADMIN);
+	ASSERT_EQ(0, unshare(CLONE_NEWNET));
+	clear_cap(_metadata, CAP_SYS_ADMIN);
+}
+
+static int test_socket(const struct service_fixture *const srv)
+{
+	int fd;
+
+	fd = socket(srv->protocol.family, srv->protocol.type | SOCK_CLOEXEC, 0);
+	if (fd < 0)
+		return errno;
+	/*
+	 * Mixing error codes from close(2) and socket(2) should not lead to any
+	 * (access type) confusion for this test.
+	 */
+	if (close(fd) != 0)
+		return errno;
+	return 0;
+}
+
+FIXTURE(protocol)
+{
+	struct service_fixture srv0, unspec_srv0;
+};
+
+FIXTURE_VARIANT(protocol)
+{
+	const struct protocol_variant protocol;
+};
+
+FIXTURE_SETUP(protocol)
+{
+	const struct protocol_variant prot_unspec = {
+		.family = AF_UNSPEC,
+		.type = SOCK_STREAM,
+	};
+
+	disable_caps(_metadata);
+	self->srv0.protocol = variant->protocol;
+	self->unspec_srv0.protocol = prot_unspec;
+	setup_namespace(_metadata);
+};
+
+FIXTURE_TEARDOWN(protocol)
+{
+}
+
+/* clang-format off */
+FIXTURE_VARIANT_ADD(protocol, unix_stream) {
+	/* clang-format on */
+	.protocol = {
+		.family = AF_UNIX,
+		.type = SOCK_STREAM,
+	},
+};
+
+/* clang-format off */
+FIXTURE_VARIANT_ADD(protocol, unix_dgram) {
+	/* clang-format on */
+	.protocol = {
+		.family = AF_UNIX,
+		.type = SOCK_DGRAM,
+	},
+};
+
+/* clang-format off */
+FIXTURE_VARIANT_ADD(protocol, ipv4_tcp) {
+	/* clang-format on */
+	.protocol = {
+		.family = AF_INET,
+		.type = SOCK_STREAM,
+	},
+};
+
+/* clang-format off */
+FIXTURE_VARIANT_ADD(protocol, ipv4_udp) {
+	/* clang-format on */
+	.protocol = {
+		.family = AF_INET,
+		.type = SOCK_DGRAM,
+	},
+};
+
+/* clang-format off */
+FIXTURE_VARIANT_ADD(protocol, ipv6_tcp) {
+	/* clang-format on */
+	.protocol = {
+		.family = AF_INET6,
+		.type = SOCK_STREAM,
+	},
+};
+
+/* clang-format off */
+FIXTURE_VARIANT_ADD(protocol, ipv6_udp) {
+	/* clang-format on */
+	.protocol = {
+		.family = AF_INET6,
+		.type = SOCK_DGRAM,
+	},
+};
+
+TEST_F(protocol, create)
+{
+	const struct landlock_ruleset_attr ruleset_attr = {
+		.handled_access_socket = LANDLOCK_ACCESS_SOCKET_CREATE,
+	};
+	const struct landlock_socket_attr create_socket_attr = {
+		.allowed_access = LANDLOCK_ACCESS_SOCKET_CREATE,
+		.family = self->srv0.protocol.family,
+		.type = self->srv0.protocol.type,
+	};
+
+	int ruleset_fd;
+
+	/* Allowed create */
+	ruleset_fd =
+		landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
+	ASSERT_LE(0, ruleset_fd);
+
+	ASSERT_EQ(0, landlock_add_rule(ruleset_fd, LANDLOCK_RULE_SOCKET,
+				       &create_socket_attr, 0));
+
+	enforce_ruleset(_metadata, ruleset_fd);
+	EXPECT_EQ(0, close(ruleset_fd));
+
+	ASSERT_EQ(0, test_socket(&self->srv0));
+	ASSERT_EQ(EAFNOSUPPORT, test_socket(&self->unspec_srv0));
+
+	/* Denied create */
+	ruleset_fd =
+		landlock_create_ruleset(&ruleset_attr, sizeof(ruleset_attr), 0);
+	ASSERT_LE(0, ruleset_fd);
+
+	enforce_ruleset(_metadata, ruleset_fd);
+	EXPECT_EQ(0, close(ruleset_fd));
+
+	ASSERT_EQ(EACCES, test_socket(&self->srv0));
+	ASSERT_EQ(EAFNOSUPPORT, test_socket(&self->unspec_srv0));
+}
+
+TEST_HARNESS_MAIN
-- 
2.34.1