Add landlock08 test

Verify the landlock support for bind() syscall under IPV4 and IPV6
sockets. In particular, check that bind() is not assigning ad address
for a specific TCP port, if landlock didn't enforce the
LANDLOCK_ACCESS_NET_BIND_TCP rule in the current sandbox.

Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.com>

include/lapi/capability.h

@@ -20,6 +20,10 @@
 # endif
 #endif
 
+#ifndef CAP_NET_BIND_SERVICE
+# define CAP_NET_BIND_SERVICE 10
+#endif
+
 #ifndef CAP_NET_RAW
 # define CAP_NET_RAW          13
 #endif

runtest/syscalls

@@ -707,6 +707,7 @@ landlock04 landlock04
 landlock05 landlock05
 landlock06 landlock06
 landlock07 landlock07
+landlock08 landlock08
 
 lchown01 lchown01
 lchown01_16 lchown01_16

testcases/kernel/syscalls/landlock/.gitignore

@@ -6,3 +6,4 @@ landlock04
 landlock05
 landlock06
 landlock07
+landlock08

testcases/kernel/syscalls/landlock/landlock08.c

@@ -0,0 +1,131 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2024 SUSE LLC Andrea Cervesato <andrea.cervesato@suse.com>
+ */
+
+/*\
+ * [Description]
+ *
+ * Verify the landlock support for bind() syscall under IPV4 and IPV6 sockets.
+ * In particular, check that bind() is not assigning an address for a
+ * specific TCP port, if landlock didn't enforce the
+ * LANDLOCK_ACCESS_NET_BIND_TCP rule in the current sandbox.
+ *
+ * [Algorithm]
+ *
+ * Repeat the following procedure for IPV4 and IPV6:
+ *
+ * - create a socket on PORT1, bind() it and check if it passes
+ * - enforce the current sandbox with LANDLOCK_ACCESS_NET_BIND_TCP on PORT1
+ * - create a socket on PORT1, bind() it and check if it passes
+ * - create a socket on PORT2, bind() it and check if it fails
+ */
+
+#include "landlock_common.h"
+
+#define ADDRESS_PORT 0x7c90
+#define IPV4_ADDRESS "127.0.0.1"
+#define IPV6_ADDRESS "::1"
+
+static int variants[] = {
+	AF_INET,
+	AF_INET6,
+};
+
+static struct tst_landlock_ruleset_attr *ruleset_attr;
+static struct landlock_net_port_attr *net_port_attr;
+static struct sockaddr_in ipv4_addr;
+static struct sockaddr_in6 ipv6_addr;
+
+static void test_bind(const int addr_family, const int port, const int exp_err)
+{
+	struct sockaddr *sock_addr;
+	size_t sock_addr_size;
+	char *addr_str;
+	int sock_fd;
+
+	switch (addr_family) {
+	case AF_INET:
+		tst_init_sockaddr_inet(&ipv4_addr, IPV4_ADDRESS, port);
+
+		addr_str = IPV4_ADDRESS;
+		sock_addr = (struct sockaddr *)&ipv4_addr;
+		sock_addr_size = sizeof(struct sockaddr_in);
+		break;
+	case AF_INET6:
+		tst_init_sockaddr_inet6(&ipv6_addr, IPV6_ADDRESS, port);
+
+		addr_str = IPV6_ADDRESS;
+		sock_addr = (struct sockaddr *)&ipv6_addr;
+		sock_addr_size = sizeof(struct sockaddr_in6);
+		break;
+	default:
+		tst_brk(TBROK, "Unsupported variant");
+		return;
+	};
+
+	sock_fd = SAFE_SOCKET(addr_family, SOCK_STREAM | SOCK_CLOEXEC, 0);
+
+	tst_res(TINFO, "Socket listening on %s:%d", addr_str, port);
+
+	if (exp_err) {
+		TST_EXP_FAIL(bind(sock_fd, sock_addr, sock_addr_size),
+			exp_err, "bind() access to %s:%d",
+			addr_str, port);
+	} else {
+		TST_EXP_PASS(bind(sock_fd, sock_addr, sock_addr_size),
+			"bind() access to %s:%d",
+			addr_str, port);
+	}
+
+	SAFE_CLOSE(sock_fd);
+}
+
+static void run(void)
+{
+	int addr_family = variants[tst_variant];
+
+	tst_res(TINFO, "Using %s protocol",
+		addr_family == AF_INET ? "IPV4" : "IPV6");
+
+	test_bind(addr_family, ADDRESS_PORT, 0);
+
+	tst_res(TINFO, "Enable bind() access only for port %d", ADDRESS_PORT);
+
+	apply_landlock_net_layer(ruleset_attr, net_port_attr, ADDRESS_PORT,
+		LANDLOCK_ACCESS_NET_BIND_TCP);
+
+	test_bind(addr_family, ADDRESS_PORT, 0);
+	test_bind(addr_family, ADDRESS_PORT + 0x80, EACCES);
+}
+
+static void setup(void)
+{
+	verify_landlock_is_enabled();
+
+	ruleset_attr->data.handled_access_net = LANDLOCK_ACCESS_NET_BIND_TCP;
+}
+
+static struct tst_test test = {
+	.test_all = run,
+	.setup = setup,
+	.needs_root = 1,
+	.needs_tmpdir = 1,
+	.test_variants = ARRAY_SIZE(variants),
+	.bufs = (struct tst_buffers[]) {
+		{&ruleset_attr, .size = sizeof(struct tst_landlock_ruleset_attr)},
+		{&net_port_attr, .size = sizeof(struct landlock_net_port_attr)},
+		{},
+	},
+	.caps = (struct tst_cap []) {
+		TST_CAP(TST_CAP_REQ, CAP_SYS_ADMIN),
+		TST_CAP(TST_CAP_REQ, CAP_NET_BIND_SERVICE),
+		{}
+	},
+	.needs_kconfigs = (const char *[]) {
+		"CONFIG_NET=y",
+		"CONFIG_INET=y",
+		"CONFIG_IPV6=y",
+		NULL
+	}
+};