[PATCH v10 4/6] selftests/Landlock: Add pathname UNIX socket tests

This patch expands abstract UNIX socket restriction tests by
testing pathname sockets connection with scoped domain.

pathname_address_sockets ensures that UNIX sockets bound to
a filesystem path name can still connect to a socket outside
of their scoped domain. This means that even if the domain
is scoped with LANDLOCK_SCOPED_ABSTRACT_UNIX_SOCKET, the
socket can connect to a socket outside the scoped domain.

Signed-off-by: Tahera Fahimi <[email protected]>
---
changes in versions:
v10:
- Code improvements by changing fixture variables to local ones.
- Commit improvement.
v9:
- Moving remove_path() back to fs_test.c, and using unlink(2)
  and rmdir(2) instead.
- Removing hard-coded numbers and using "backlog" instead.
V8:
- Adding pathname_address_sockets to cover all types of address
  formats for unix sockets, and moving remove_path() to
  common.h to reuse in this test.
---
 .../landlock/scoped_abstract_unix_test.c      | 199 ++++++++++++++++++
 1 file changed, 199 insertions(+)

diff --git a/tools/testing/selftests/landlock/scoped_abstract_unix_test.c b/tools/testing/selftests/landlock/scoped_abstract_unix_test.c
index 65c1ac2895a9..401e0d2e7025 100644
--- a/tools/testing/selftests/landlock/scoped_abstract_unix_test.c
+++ b/tools/testing/selftests/landlock/scoped_abstract_unix_test.c
@@ -928,4 +928,203 @@ TEST_F(outside_socket, socket_with_different_domain)
 		_metadata->exit_code = KSFT_FAIL;
 }
 
+static const char path1[] = TMP_DIR "/s1_variant1";
+static const char path2[] = TMP_DIR "/s2_variant1";
+
+/* clang-format off */
+FIXTURE(pathname_address_sockets) {};
+/* clang-format on */
+
+FIXTURE_VARIANT(pathname_address_sockets)
+{
+	const int domain;
+};
+
+/* clang-format off */
+FIXTURE_VARIANT_ADD(pathname_address_sockets, pathname_socket_scoped_domain) {
+	/* clang-format on */
+	.domain = SCOPE_SANDBOX,
+};
+
+/* clang-format off */
+FIXTURE_VARIANT_ADD(pathname_address_sockets, pathname_socket_other_domain) {
+	/* clang-format on */
+	.domain = OTHER_SANDBOX,
+};
+
+/* clang-format off */
+FIXTURE_VARIANT_ADD(pathname_address_sockets, pathname_socket_no_domain) {
+	/* clang-format on */
+	.domain = NO_SANDBOX,
+};
+
+FIXTURE_SETUP(pathname_address_sockets)
+{
+	disable_caps(_metadata);
+	umask(0077);
+	ASSERT_EQ(0, mkdir(TMP_DIR, 0700));
+
+	ASSERT_EQ(0, mknod(path1, S_IFREG | 0700, 0))
+	{
+		TH_LOG("Failed to create file \"%s\": %s", path1,
+		       strerror(errno));
+		ASSERT_EQ(0, unlink(TMP_DIR) & rmdir(TMP_DIR));
+	}
+	ASSERT_EQ(0, mknod(path2, S_IFREG | 0700, 0))
+	{
+		TH_LOG("Failed to create file \"%s\": %s", path2,
+		       strerror(errno));
+		ASSERT_EQ(0, unlink(TMP_DIR) & rmdir(TMP_DIR));
+	}
+}
+
+FIXTURE_TEARDOWN(pathname_address_sockets)
+{
+	ASSERT_EQ(0, unlink(path1) & rmdir(path1));
+	ASSERT_EQ(0, unlink(path2) & rmdir(path2));
+	ASSERT_EQ(0, unlink(TMP_DIR) & rmdir(TMP_DIR));
+}
+
+TEST_F(pathname_address_sockets, scoped_pathname_sockets)
+{
+	struct service_fixture stream_address, dgram_address;
+	const char *const stream_path = path1;
+	const char *const dgram_path = path2;
+	socklen_t size, size_dg;
+	struct sockaddr_un srv_un, srv_un_dg;
+	int pipe_parent[2];
+	pid_t child;
+	int status;
+	char buf_child;
+	int socket_fds_stream[2];
+
+	/* setup abstract addresses */
+	memset(&stream_address, 0, sizeof(stream_address));
+	set_unix_address(&stream_address, 0);
+	memset(&dgram_address, 0, sizeof(dgram_address));
+	set_unix_address(&dgram_address, 0);
+
+	ASSERT_EQ(0, socketpair(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0,
+				socket_fds_stream));
+
+	srv_un.sun_family = AF_UNIX;
+	snprintf(srv_un.sun_path, sizeof(srv_un.sun_path), "%s", stream_path);
+	size = offsetof(struct sockaddr_un, sun_path) + strlen(srv_un.sun_path);
+
+	srv_un_dg.sun_family = AF_UNIX;
+	snprintf(srv_un_dg.sun_path, sizeof(srv_un_dg.sun_path), "%s",
+		 dgram_path);
+	size_dg = offsetof(struct sockaddr_un, sun_path) +
+		  strlen(srv_un_dg.sun_path);
+
+	ASSERT_EQ(0, pipe2(pipe_parent, O_CLOEXEC));
+
+	child = fork();
+	ASSERT_LE(0, child);
+	if (child == 0) {
+		int cli_fd, cli_fd_dg;
+		int err, err_dg;
+		int client, dgram_client;
+		int sample = socket(AF_UNIX, SOCK_STREAM, 0);
+
+		ASSERT_LE(0, sample);
+		ASSERT_EQ(0, close(pipe_parent[1]));
+
+		/* scope the domain */
+		if (variant->domain == SCOPE_SANDBOX)
+			create_unix_domain(_metadata);
+		else if (variant->domain == OTHER_SANDBOX)
+			create_fs_domain(_metadata);
+
+		ASSERT_EQ(0, close(socket_fds_stream[1]));
+		ASSERT_EQ(0, send_fd(socket_fds_stream[0], sample));
+		ASSERT_EQ(0, close(sample));
+		ASSERT_EQ(0, close(socket_fds_stream[0]));
+
+		/* wait for server to listen */
+		ASSERT_EQ(1, read(pipe_parent[0], &buf_child, 1));
+
+		/* connect with pathname sockets */
+		cli_fd = socket(AF_UNIX, SOCK_STREAM, 0);
+		ASSERT_LE(0, cli_fd);
+		ASSERT_EQ(0, connect(cli_fd, &srv_un, size));
+		ASSERT_EQ(0, close(cli_fd));
+
+		cli_fd_dg = socket(AF_UNIX, SOCK_DGRAM, 0);
+		ASSERT_LE(0, cli_fd_dg);
+		ASSERT_EQ(0, connect(cli_fd_dg, &srv_un_dg, size_dg));
+
+		ASSERT_EQ(0, close(cli_fd_dg));
+
+		/* check connection with abstract sockets */
+		client = socket(AF_UNIX, SOCK_STREAM, 0);
+		dgram_client = socket(AF_UNIX, SOCK_DGRAM, 0);
+
+		ASSERT_NE(-1, client);
+		ASSERT_NE(-1, dgram_client);
+
+		err = connect(client, &stream_address.unix_addr,
+			      stream_address.unix_addr_len);
+		err_dg = connect(dgram_client, &dgram_address.unix_addr,
+				 dgram_address.unix_addr_len);
+		if (variant->domain == SCOPE_SANDBOX) {
+			EXPECT_EQ(-1, err);
+			EXPECT_EQ(-1, err_dg);
+			EXPECT_EQ(EPERM, errno);
+		} else {
+			EXPECT_EQ(0, err);
+			EXPECT_EQ(0, err_dg);
+		}
+		ASSERT_EQ(0, close(client));
+		ASSERT_EQ(0, close(dgram_client));
+
+		_exit(_metadata->exit_code);
+		return;
+	}
+	int srv_fd, srv_fd_dg, server, dgram_server;
+	int recv_data;
+
+	ASSERT_EQ(0, close(pipe_parent[0]));
+
+	recv_data = recv_fd(socket_fds_stream[1]);
+	ASSERT_LE(0, recv_data);
+	ASSERT_LE(0, close(socket_fds_stream[1]));
+
+	/* Sets up a server */
+	srv_fd = socket(AF_UNIX, SOCK_STREAM, 0);
+	ASSERT_LE(0, srv_fd);
+	ASSERT_EQ(0, unlink(stream_path));
+	ASSERT_EQ(0, bind(srv_fd, &srv_un, size));
+	ASSERT_EQ(0, listen(srv_fd, backlog));
+
+	/* set up a datagram server */
+	ASSERT_EQ(0, unlink(dgram_path));
+	srv_fd_dg = socket(AF_UNIX, SOCK_DGRAM, 0);
+	ASSERT_LE(0, srv_fd_dg);
+	ASSERT_EQ(0, bind(srv_fd_dg, (struct sockaddr *)&srv_un_dg, size_dg));
+
+	/*set up abstract servers */
+	server = socket(AF_UNIX, SOCK_STREAM, 0);
+	dgram_server = socket(AF_UNIX, SOCK_DGRAM, 0);
+	ASSERT_NE(-1, server);
+	ASSERT_NE(-1, dgram_server);
+	ASSERT_EQ(0, bind(server, &stream_address.unix_addr,
+			  stream_address.unix_addr_len));
+	ASSERT_EQ(0, bind(dgram_server, &dgram_address.unix_addr,
+			  dgram_address.unix_addr_len));
+	ASSERT_EQ(0, listen(server, backlog));
+
+	/* servers are listening, signal to child */
+	ASSERT_EQ(1, write(pipe_parent[1], ".", 1));
+	ASSERT_EQ(child, waitpid(child, &status, 0));
+	ASSERT_EQ(0, close(srv_fd));
+	ASSERT_EQ(0, close(srv_fd_dg));
+	ASSERT_EQ(0, close(server));
+	ASSERT_EQ(0, close(dgram_server));
+
+	if (WIFSIGNALED(status) || !WIFEXITED(status) ||
+	    WEXITSTATUS(status) != EXIT_SUCCESS)
+		_metadata->exit_code = KSFT_FAIL;
+}
+
 TEST_HARNESS_MAIN
-- 
2.34.1