helper: rearrange initialisation args

This improves consistency across two different helper implementations.

Signed-off-by: Ophestra <cat@gensokyo.uk>

dbus/run.go

@@ -28,25 +28,25 @@ func (p *Proxy) Start(ctx context.Context, output io.Writer, sandbox bool) error
 	var (
 		h helper.Helper
 
-		argF = func(argsFD, statFD int) []string {
+		argF = func(argsFd, statFd int) []string {
-			if statFD == -1 {
+			if statFd == -1 {
-				return []string{"--args=" + strconv.Itoa(argsFD)}
+				return []string{"--args=" + strconv.Itoa(argsFd)}
 			} else {
-				return []string{"--args=" + strconv.Itoa(argsFD), "--fd=" + strconv.Itoa(statFD)}
+				return []string{"--args=" + strconv.Itoa(argsFd), "--fd=" + strconv.Itoa(statFd)}
 			}
 		}
 	)
 
 	c, cancel := context.WithCancelCause(ctx)
 	if !sandbox {
-		h = helper.NewDirect(c, p.seal, p.name, argF, func(cmd *exec.Cmd) {
+		h = helper.NewDirect(c, p.name, p.seal, true, argF, func(cmd *exec.Cmd) {
 			if output != nil {
 				cmd.Stdout, cmd.Stderr = output, output
 			}
 
 			// xdg-dbus-proxy does not need to inherit the environment
 			cmd.Env = make([]string, 0)
-		}, true)
+		})
 	} else {
 		// look up absolute path if name is just a file name
 		toolPath := p.name
@@ -116,11 +116,11 @@ func (p *Proxy) Start(ctx context.Context, output io.Writer, sandbox bool) error
 			bc.Bind(k, k)
 		}
 
-		h = helper.MustNewBwrap(c, bc, toolPath, true, p.seal, argF, func(cmd *exec.Cmd) {
+		h = helper.MustNewBwrap(c, toolPath, p.seal, true, argF, func(cmd *exec.Cmd) {
 			if output != nil {
 				cmd.Stdout, cmd.Stderr = output, output
 			}
-		}, nil, nil, true)
+		}, bc, true, nil, nil)
 		p.bwrap = bc
 	}
 

helper/args_test.go

@@ -9,7 +9,7 @@ import (
 	"git.gensokyo.uk/security/fortify/helper"
 )
 
-func Test_argsFD_String(t *testing.T) {
+func Test_argsFd_String(t *testing.T) {
 	wantString := strings.Join(wantArgs, " ")
 	if got := argsWt.(fmt.Stringer).String(); got != wantString {
 		t.Errorf("String(): got %v; want %v",

helper/bwrap.go

@@ -51,17 +51,17 @@ func (b *bubblewrap) Start() error {
 // Function argF returns an array of arguments passed directly to the child process.
 func MustNewBwrap(
 	ctx context.Context,
-	conf *bwrap.Config,
 	name string,
-	setpgid bool,
 	wt io.WriterTo,
-	argF func(argsFD, statFD int) []string,
+	stat bool,
+	argF func(argsFd, statFd int) []string,
 	cmdF func(cmd *exec.Cmd),
+	conf *bwrap.Config,
+	setpgid bool,
 	extraFiles []*os.File,
 	syncFd *os.File,
-	stat bool,
 ) Helper {
-	b, err := NewBwrap(ctx, conf, name, setpgid, wt, argF, cmdF, extraFiles, syncFd, stat)
+	b, err := NewBwrap(ctx, name, wt, stat, argF, cmdF, conf, setpgid, extraFiles, syncFd)
 	if err != nil {
 		panic(err.Error())
 	} else {
@@ -74,20 +74,20 @@ func MustNewBwrap(
 // Function argF returns an array of arguments passed directly to the child process.
 func NewBwrap(
 	ctx context.Context,
-	conf *bwrap.Config,
 	name string,
-	setpgid bool,
 	wt io.WriterTo,
+	stat bool,
 	argF func(argsFd, statFd int) []string,
 	cmdF func(cmd *exec.Cmd),
+	conf *bwrap.Config,
+	setpgid bool,
 	extraFiles []*os.File,
 	syncFd *os.File,
-	stat bool,
 ) (Helper, error) {
 	b := new(bubblewrap)
 
 	b.name = name
-	b.helperCmd = newHelperCmd(ctx, BubblewrapName, wt, argF, extraFiles, stat)
+	b.helperCmd = newHelperCmd(ctx, BubblewrapName, wt, argF, stat, extraFiles)
 	if setpgid {
 		b.Cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
 	}

helper/bwrap_test.go

@@ -33,9 +33,10 @@ func TestBwrap(t *testing.T) {
 
 		h := helper.MustNewBwrap(
 			context.Background(),
-			sc, "fortify", false,
+			"fortify",
-			argsWt, argF, nil,
+			argsWt, false,
-			nil, nil, false,
+			argF, nil,
+			sc, false, nil, nil,
 		)
 
 		if err := h.Start(); !errors.Is(err, os.ErrNotExist) {
@@ -47,9 +48,10 @@ func TestBwrap(t *testing.T) {
 	t.Run("valid new helper nil check", func(t *testing.T) {
 		if got := helper.MustNewBwrap(
 			context.TODO(),
-			sc, "fortify", false,
+			"fortify",
-			argsWt, argF, nil,
+			argsWt, false,
-			nil, nil, false,
+			argF, nil,
+			sc, false, nil, nil,
 		); got == nil {
 			t.Errorf("MustNewBwrap(%#v, %#v, %#v) got nil",
 				sc, argsWt, "fortify")
@@ -68,22 +70,24 @@ func TestBwrap(t *testing.T) {
 
 		helper.MustNewBwrap(
 			context.TODO(),
-			&bwrap.Config{Hostname: "\x00"}, "fortify", false,
+			"fortify",
-			nil, argF, nil,
+			nil, false,
-			nil, nil, false,
+			argF, nil,
+			&bwrap.Config{Hostname: "\x00"}, false, nil, nil,
 		)
 	})
 
 	t.Run("start without pipes", func(t *testing.T) {
 		helper.InternalReplaceExecCommand(t)
 
-		c, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+		ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 		defer cancel()
 		stdout, stderr := new(strings.Builder), new(strings.Builder)
 		h := helper.MustNewBwrap(
-			c, sc, "crash-test-dummy", false,
+			ctx, "crash-test-dummy",
-			nil, argFChecked, func(cmd *exec.Cmd) { cmd.Stdout, cmd.Stderr = stdout, stderr },
+			nil, false,
-			nil, nil, false,
+			argFChecked, func(cmd *exec.Cmd) { cmd.Stdout, cmd.Stderr = stdout, stderr },
+			sc, false, nil, nil,
 		)
 
 		if err := h.Start(); err != nil {
@@ -101,8 +105,10 @@ func TestBwrap(t *testing.T) {
 	t.Run("implementation compliance", func(t *testing.T) {
 		testHelper(t, func(ctx context.Context, cmdF func(cmd *exec.Cmd), stat bool) helper.Helper {
 			return helper.MustNewBwrap(
-				ctx, sc, "crash-test-dummy", false,
+				ctx, "crash-test-dummy",
-				argsWt, argF, cmdF, nil, nil, stat,
+				argsWt, stat,
+				argF, cmdF,
+				sc, false, nil, nil,
 			)
 		})
 	})

helper/direct.go

@@ -17,14 +17,14 @@ import (
 // Function argF returns an array of arguments passed directly to the child process.
 func NewDirect(
 	ctx context.Context,
-	wt io.WriterTo,
 	name string,
+	wt io.WriterTo,
+	stat bool,
 	argF func(argsFd, statFd int) []string,
 	cmdF func(cmd *exec.Cmd),
-	stat bool,
 ) Helper {
 	d := new(direct)
-	d.helperCmd = newHelperCmd(ctx, name, wt, argF, nil, stat)
+	d.helperCmd = newHelperCmd(ctx, name, wt, argF, stat, nil)
 	if cmdF != nil {
 		cmdF(d.helperCmd.Cmd)
 	}
@@ -53,9 +53,12 @@ func (h *direct) Start() error {
 }
 
 func newHelperCmd(
-	ctx context.Context, name string,
+	ctx context.Context,
-	wt io.WriterTo, argF func(argsFd, statFd int) []string,
+	name string,
-	extraFiles []*os.File, stat bool,
+	wt io.WriterTo,
+	argF func(argsFd, statFd int) []string,
+	stat bool,
+	extraFiles []*os.File,
 ) (cmd *helperCmd) {
 	cmd = new(helperCmd)
 	cmd.ctx = ctx

helper/direct_test.go

@@ -12,7 +12,7 @@ import (
 
 func TestDirect(t *testing.T) {
 	t.Run("start non-existent helper path", func(t *testing.T) {
-		h := helper.NewDirect(context.Background(), argsWt, "/nonexistent", argF, nil, false)
+		h := helper.NewDirect(context.Background(), "/nonexistent", argsWt, false, argF, nil)
 
 		if err := h.Start(); !errors.Is(err, os.ErrNotExist) {
 			t.Errorf("Start: error = %v, wantErr %v",
@@ -21,7 +21,7 @@ func TestDirect(t *testing.T) {
 	})
 
 	t.Run("valid new helper nil check", func(t *testing.T) {
-		if got := helper.NewDirect(context.TODO(), argsWt, "fortify", argF, nil, false); got == nil {
+		if got := helper.NewDirect(context.TODO(), "fortify", argsWt, false, argF, nil); got == nil {
 			t.Errorf("New(%q, %q) got nil",
 				argsWt, "fortify")
 			return
@@ -30,7 +30,7 @@ func TestDirect(t *testing.T) {
 
 	t.Run("implementation compliance", func(t *testing.T) {
 		testHelper(t, func(ctx context.Context, cmdF func(cmd *exec.Cmd), stat bool) helper.Helper {
-			return helper.NewDirect(ctx, argsWt, "crash-test-dummy", argF, cmdF, stat)
+			return helper.NewDirect(ctx, "crash-test-dummy", argsWt, stat, argF, cmdF)
 		})
 	})
 }

internal/app/shim/main.go

@@ -128,13 +128,11 @@ func Main() {
 	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
 	defer stop() // unreachable
 	if b, err := helper.NewBwrap(
-		ctx,
+		ctx, path.Join(fst.Tmp, "sbin/init0"),
-		conf, path.Join(fst.Tmp, "sbin/init0"), false,
+		nil, false,
-		nil, func(int, int) []string { return make([]string, 0) },
+		func(int, int) []string { return make([]string, 0) },
 		func(cmd *exec.Cmd) { cmd.Stdin, cmd.Stdout, cmd.Stderr = os.Stdin, os.Stdout, os.Stderr },
-		extraFiles,
+		conf, false, extraFiles, syncFd,
-		syncFd,
-		false,
 	); err != nil {
 		log.Fatalf("malformed sandbox config: %v", err)
 	} else {