Example #1
0
// TestPassFD tests passing a file descriptor over a Unix socket.
//
// This test involved both a parent and child process. The parent
// process is invoked as a normal test, with "go test", which then
// runs the child process by running the current test binary with args
// "-test.run=^TestPassFD$" and an environment variable used to signal
// that the test should become the child process instead.
func TestPassFD(t *testing.T) {
	switch runtime.GOOS {
	case "dragonfly":
		// TODO(jsing): Figure out why sendmsg is returning EINVAL.
		t.Skip("skipping test on dragonfly")
	case "solaris":
		// TODO(aram): Figure out why ReadMsgUnix is returning empty message.
		t.Skip("skipping test on solaris, see issue 7402")
	}
	if os.Getenv("GO_WANT_HELPER_PROCESS") == "1" {
		passFDChild()
		return
	}

	tempDir, err := ioutil.TempDir("", "TestPassFD")
	if err != nil {
		t.Fatal(err)
	}
	defer os.RemoveAll(tempDir)

	fds, err := unix.Socketpair(unix.AF_LOCAL, unix.SOCK_STREAM, 0)
	if err != nil {
		t.Fatalf("Socketpair: %v", err)
	}
	defer unix.Close(fds[0])
	defer unix.Close(fds[1])
	writeFile := os.NewFile(uintptr(fds[0]), "child-writes")
	readFile := os.NewFile(uintptr(fds[1]), "parent-reads")
	defer writeFile.Close()
	defer readFile.Close()

	cmd := exec.Command(os.Args[0], "-test.run=^TestPassFD$", "--", tempDir)
	cmd.Env = []string{"GO_WANT_HELPER_PROCESS=1"}
	if lp := os.Getenv("LD_LIBRARY_PATH"); lp != "" {
		cmd.Env = append(cmd.Env, "LD_LIBRARY_PATH="+lp)
	}
	cmd.ExtraFiles = []*os.File{writeFile}

	out, err := cmd.CombinedOutput()
	if len(out) > 0 || err != nil {
		t.Fatalf("child process: %q, %v", out, err)
	}

	c, err := net.FileConn(readFile)
	if err != nil {
		t.Fatalf("FileConn: %v", err)
	}
	defer c.Close()

	uc, ok := c.(*net.UnixConn)
	if !ok {
		t.Fatalf("unexpected FileConn type; expected UnixConn, got %T", c)
	}

	buf := make([]byte, 32) // expect 1 byte
	oob := make([]byte, 32) // expect 24 bytes
	closeUnix := time.AfterFunc(5*time.Second, func() {
		t.Logf("timeout reading from unix socket")
		uc.Close()
	})
	_, oobn, _, _, err := uc.ReadMsgUnix(buf, oob)
	closeUnix.Stop()

	scms, err := unix.ParseSocketControlMessage(oob[:oobn])
	if err != nil {
		t.Fatalf("ParseSocketControlMessage: %v", err)
	}
	if len(scms) != 1 {
		t.Fatalf("expected 1 SocketControlMessage; got scms = %#v", scms)
	}
	scm := scms[0]
	gotFds, err := unix.ParseUnixRights(&scm)
	if err != nil {
		t.Fatalf("unix.ParseUnixRights: %v", err)
	}
	if len(gotFds) != 1 {
		t.Fatalf("wanted 1 fd; got %#v", gotFds)
	}

	f := os.NewFile(uintptr(gotFds[0]), "fd-from-child")
	defer f.Close()

	got, err := ioutil.ReadAll(f)
	want := "Hello from child process!\n"
	if string(got) != want {
		t.Errorf("child process ReadAll: %q, %v; want %q", got, err, want)
	}
}
Example #2
0
// TestSCMCredentials tests the sending and receiving of credentials
// (PID, UID, GID) in an ancillary message between two UNIX
// sockets. The SO_PASSCRED socket option is enabled on the sending
// socket for this to work.
func TestSCMCredentials(t *testing.T) {
	fds, err := unix.Socketpair(unix.AF_LOCAL, unix.SOCK_STREAM, 0)
	if err != nil {
		t.Fatalf("Socketpair: %v", err)
	}
	defer unix.Close(fds[0])
	defer unix.Close(fds[1])

	err = unix.SetsockoptInt(fds[0], unix.SOL_SOCKET, unix.SO_PASSCRED, 1)
	if err != nil {
		t.Fatalf("SetsockoptInt: %v", err)
	}

	srvFile := os.NewFile(uintptr(fds[0]), "server")
	defer srvFile.Close()
	srv, err := net.FileConn(srvFile)
	if err != nil {
		t.Errorf("FileConn: %v", err)
		return
	}
	defer srv.Close()

	cliFile := os.NewFile(uintptr(fds[1]), "client")
	defer cliFile.Close()
	cli, err := net.FileConn(cliFile)
	if err != nil {
		t.Errorf("FileConn: %v", err)
		return
	}
	defer cli.Close()

	var ucred unix.Ucred
	if os.Getuid() != 0 {
		ucred.Pid = int32(os.Getpid())
		ucred.Uid = 0
		ucred.Gid = 0
		oob := unix.UnixCredentials(&ucred)
		_, _, err := cli.(*net.UnixConn).WriteMsgUnix(nil, oob, nil)
		if err.(*net.OpError).Err != syscall.EPERM {
			t.Fatalf("WriteMsgUnix failed with %v, want EPERM", err)
		}
	}

	ucred.Pid = int32(os.Getpid())
	ucred.Uid = uint32(os.Getuid())
	ucred.Gid = uint32(os.Getgid())
	oob := unix.UnixCredentials(&ucred)

	// this is going to send a dummy byte
	n, oobn, err := cli.(*net.UnixConn).WriteMsgUnix(nil, oob, nil)
	if err != nil {
		t.Fatalf("WriteMsgUnix: %v", err)
	}
	if n != 0 {
		t.Fatalf("WriteMsgUnix n = %d, want 0", n)
	}
	if oobn != len(oob) {
		t.Fatalf("WriteMsgUnix oobn = %d, want %d", oobn, len(oob))
	}

	oob2 := make([]byte, 10*len(oob))
	n, oobn2, flags, _, err := srv.(*net.UnixConn).ReadMsgUnix(nil, oob2)
	if err != nil {
		t.Fatalf("ReadMsgUnix: %v", err)
	}
	if flags != 0 {
		t.Fatalf("ReadMsgUnix flags = 0x%x, want 0", flags)
	}
	if n != 1 {
		t.Fatalf("ReadMsgUnix n = %d, want 1 (dummy byte)", n)
	}
	if oobn2 != oobn {
		// without SO_PASSCRED set on the socket, ReadMsgUnix will
		// return zero oob bytes
		t.Fatalf("ReadMsgUnix oobn = %d, want %d", oobn2, oobn)
	}
	oob2 = oob2[:oobn2]
	if !bytes.Equal(oob, oob2) {
		t.Fatal("ReadMsgUnix oob bytes don't match")
	}

	scm, err := unix.ParseSocketControlMessage(oob2)
	if err != nil {
		t.Fatalf("ParseSocketControlMessage: %v", err)
	}
	newUcred, err := unix.ParseUnixCredentials(&scm[0])
	if err != nil {
		t.Fatalf("ParseUnixCredentials: %v", err)
	}
	if *newUcred != ucred {
		t.Fatalf("ParseUnixCredentials = %+v, want %+v", newUcred, ucred)
	}
}