container/init: close setup pipe early

This prevents leaking the setup pipe.

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

container/init.go

@@ -330,6 +330,10 @@ func initEntrypoint(k syscallDispatcher, msg message.Msg) {
 	}
 	k.umask(oldmask)
 
+	if err := closeSetup(); err != nil {
+		k.fatalf(msg, "cannot close setup pipe: %v", err)
+	}
+
 	cmd := exec.Command(params.Path.String())
 	cmd.Stdin, cmd.Stdout, cmd.Stderr = os.Stdin, os.Stdout, os.Stderr
 	cmd.Args = params.Args
@@ -342,11 +346,6 @@ func initEntrypoint(k syscallDispatcher, msg message.Msg) {
 		k.fatalf(msg, "%v", err)
 	}
 
-	if err := closeSetup(); err != nil {
-		k.printf(msg, "cannot close setup pipe: %v", err)
-		// not fatal
-	}
-
 	type winfo struct {
 		wpid    int
 		wstatus WaitStatus

container/init_test.go

@@ -1983,6 +1983,7 @@ func TestInitEntrypoint(t *testing.T) {
 				call("newFile", stub.ExpectArgs{uintptr(0x3a), "extra file 0"}, (*os.File)(nil), nil),
 				call("newFile", stub.ExpectArgs{uintptr(0x3b), "extra file 1"}, (*os.File)(nil), nil),
 				call("umask", stub.ExpectArgs{022}, 0, nil),
+				call("fatalf", stub.ExpectArgs{"cannot close setup pipe: %v", []any{stub.UniqueError(13)}}, nil, nil),
 				call("verbosef", stub.ExpectArgs{"starting initial program %s", []any{check.MustAbs("/run/current-system/sw/bin/bash")}}, nil, nil),
 				call("start", stub.ExpectArgs{"/run/current-system/sw/bin/bash", []string{"bash", "-c", "false"}, ([]string)(nil), "/.hakurei/nonexistent"}, nil, stub.UniqueError(12)),
 				call("fatalf", stub.ExpectArgs{"%v", []any{stub.UniqueError(12)}}, nil, nil),
@@ -2061,9 +2062,9 @@ func TestInitEntrypoint(t *testing.T) {
 				call("newFile", stub.ExpectArgs{uintptr(0x3a), "extra file 0"}, (*os.File)(nil), nil),
 				call("newFile", stub.ExpectArgs{uintptr(0x3b), "extra file 1"}, (*os.File)(nil), nil),
 				call("umask", stub.ExpectArgs{022}, 0, nil),
+				call("fatalf", stub.ExpectArgs{"cannot close setup pipe: %v", []any{stub.UniqueError(10)}}, nil, nil),
 				call("verbosef", stub.ExpectArgs{"starting initial program %s", []any{check.MustAbs("/run/current-system/sw/bin/bash")}}, nil, nil),
 				call("start", stub.ExpectArgs{"/run/current-system/sw/bin/bash", []string{"bash", "-c", "false"}, ([]string)(nil), "/.hakurei/nonexistent"}, &os.Process{Pid: 0xbad}, nil),
-				call("printf", stub.ExpectArgs{"cannot close setup pipe: %v", []any{stub.UniqueError(10)}}, nil, nil),
 				call("New", stub.ExpectArgs{}, nil, nil),
 				call("notify", stub.ExpectArgs{func(c chan<- os.Signal) { c <- CancelSignal }, []os.Signal{CancelSignal, os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT}}, nil, nil),
 				call("verbose", stub.ExpectArgs{[]any{"forwarding context cancellation"}}, nil, nil),
@@ -2161,9 +2162,9 @@ func TestInitEntrypoint(t *testing.T) {
 				call("newFile", stub.ExpectArgs{uintptr(0x3a), "extra file 0"}, (*os.File)(nil), nil),
 				call("newFile", stub.ExpectArgs{uintptr(0x3b), "extra file 1"}, (*os.File)(nil), nil),
 				call("umask", stub.ExpectArgs{022}, 0, nil),
+				call("fatalf", stub.ExpectArgs{"cannot close setup pipe: %v", []any{stub.UniqueError(7)}}, nil, nil),
 				call("verbosef", stub.ExpectArgs{"starting initial program %s", []any{check.MustAbs("/run/current-system/sw/bin/bash")}}, nil, nil),
 				call("start", stub.ExpectArgs{"/run/current-system/sw/bin/bash", []string{"bash", "-c", "false"}, ([]string)(nil), "/.hakurei/nonexistent"}, &os.Process{Pid: 0xbad}, nil),
-				call("printf", stub.ExpectArgs{"cannot close setup pipe: %v", []any{stub.UniqueError(7)}}, nil, nil),
 				call("New", stub.ExpectArgs{}, nil, nil),
 				call("notify", stub.ExpectArgs{func(c chan<- os.Signal) { c <- syscall.SIGQUIT }, []os.Signal{CancelSignal, os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT}}, nil, nil),
 				call("verbosef", stub.ExpectArgs{"got %s, forwarding to initial process", []any{"quit"}}, nil, nil),
@@ -2261,9 +2262,9 @@ func TestInitEntrypoint(t *testing.T) {
 				call("newFile", stub.ExpectArgs{uintptr(0x3a), "extra file 0"}, (*os.File)(nil), nil),
 				call("newFile", stub.ExpectArgs{uintptr(0x3b), "extra file 1"}, (*os.File)(nil), nil),
 				call("umask", stub.ExpectArgs{022}, 0, nil),
+				call("fatalf", stub.ExpectArgs{"cannot close setup pipe: %v", []any{stub.UniqueError(7)}}, nil, nil),
 				call("verbosef", stub.ExpectArgs{"starting initial program %s", []any{check.MustAbs("/run/current-system/sw/bin/bash")}}, nil, nil),
 				call("start", stub.ExpectArgs{"/run/current-system/sw/bin/bash", []string{"bash", "-c", "false"}, ([]string)(nil), "/.hakurei/nonexistent"}, &os.Process{Pid: 0xbad}, nil),
-				call("printf", stub.ExpectArgs{"cannot close setup pipe: %v", []any{stub.UniqueError(7)}}, nil, nil),
 				call("New", stub.ExpectArgs{}, nil, nil),
 				call("notify", stub.ExpectArgs{func(c chan<- os.Signal) { c <- os.Interrupt }, []os.Signal{CancelSignal, os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT}}, nil, nil),
 				call("verbosef", stub.ExpectArgs{"got %s", []any{"interrupt"}}, nil, nil),
@@ -2352,9 +2353,9 @@ func TestInitEntrypoint(t *testing.T) {
 				call("newFile", stub.ExpectArgs{uintptr(0x3a), "extra file 0"}, (*os.File)(nil), nil),
 				call("newFile", stub.ExpectArgs{uintptr(0x3b), "extra file 1"}, (*os.File)(nil), nil),
 				call("umask", stub.ExpectArgs{022}, 0, nil),
+				call("fatalf", stub.ExpectArgs{"cannot close setup pipe: %v", []any{stub.UniqueError(5)}}, nil, nil),
 				call("verbosef", stub.ExpectArgs{"starting initial program %s", []any{check.MustAbs("/run/current-system/sw/bin/bash")}}, nil, nil),
 				call("start", stub.ExpectArgs{"/run/current-system/sw/bin/bash", []string{"bash", "-c", "false"}, ([]string)(nil), "/.hakurei/nonexistent"}, &os.Process{Pid: 0xbad}, nil),
-				call("printf", stub.ExpectArgs{"cannot close setup pipe: %v", []any{stub.UniqueError(5)}}, nil, nil),
 				call("New", stub.ExpectArgs{}, nil, nil),
 				call("notify", stub.ExpectArgs{nil, []os.Signal{CancelSignal, os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT}}, nil, nil),
 				call("verbose", stub.ExpectArgs{[]any{os.ErrInvalid.Error()}}, nil, nil),
@@ -2447,9 +2448,9 @@ func TestInitEntrypoint(t *testing.T) {
 				call("newFile", stub.ExpectArgs{uintptr(0x3a), "extra file 0"}, (*os.File)(nil), nil),
 				call("newFile", stub.ExpectArgs{uintptr(0x3b), "extra file 1"}, (*os.File)(nil), nil),
 				call("umask", stub.ExpectArgs{022}, 0, nil),
+				call("fatalf", stub.ExpectArgs{"cannot close setup pipe: %v", []any{stub.UniqueError(3)}}, nil, nil),
 				call("verbosef", stub.ExpectArgs{"starting initial program %s", []any{check.MustAbs("/run/current-system/sw/bin/bash")}}, nil, nil),
 				call("start", stub.ExpectArgs{"/run/current-system/sw/bin/bash", []string{"bash", "-c", "false"}, ([]string)(nil), "/.hakurei/nonexistent"}, &os.Process{Pid: 0xbad}, nil),
-				call("printf", stub.ExpectArgs{"cannot close setup pipe: %v", []any{stub.UniqueError(3)}}, nil, nil),
 				call("New", stub.ExpectArgs{}, nil, nil),
 				call("notify", stub.ExpectArgs{nil, []os.Signal{CancelSignal, os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT}}, nil, nil),
 				call("verbose", stub.ExpectArgs{[]any{os.ErrInvalid.Error()}}, nil, nil),
@@ -2585,9 +2586,9 @@ func TestInitEntrypoint(t *testing.T) {
 				call("newFile", stub.ExpectArgs{uintptr(0x3a), "extra file 0"}, (*os.File)(nil), nil),
 				call("newFile", stub.ExpectArgs{uintptr(0x3b), "extra file 1"}, (*os.File)(nil), nil),
 				call("umask", stub.ExpectArgs{022}, 0, nil),
+				call("fatalf", stub.ExpectArgs{"cannot close setup pipe: %v", []any{stub.UniqueError(1)}}, nil, nil),
 				call("verbosef", stub.ExpectArgs{"starting initial program %s", []any{check.MustAbs("/run/current-system/sw/bin/bash")}}, nil, nil),
 				call("start", stub.ExpectArgs{"/run/current-system/sw/bin/bash", []string{"bash", "-c", "false"}, ([]string)(nil), "/.hakurei/nonexistent"}, &os.Process{Pid: 0xbad}, nil),
-				call("printf", stub.ExpectArgs{"cannot close setup pipe: %v", []any{stub.UniqueError(1)}}, nil, nil),
 				call("New", stub.ExpectArgs{}, nil, nil),
 				call("notify", stub.ExpectArgs{nil, []os.Signal{CancelSignal, os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT}}, nil, nil),
 				call("verbose", stub.ExpectArgs{[]any{os.ErrInvalid.Error()}}, nil, nil),
@@ -2727,9 +2728,9 @@ func TestInitEntrypoint(t *testing.T) {
 				call("newFile", stub.ExpectArgs{uintptr(11), "extra file 1"}, (*os.File)(nil), nil),
 				call("newFile", stub.ExpectArgs{uintptr(12), "extra file 2"}, (*os.File)(nil), nil),
 				call("umask", stub.ExpectArgs{022}, 0, nil),
+				call("fatalf", stub.ExpectArgs{"cannot close setup pipe: %v", []any{stub.UniqueError(0)}}, nil, nil),
 				call("verbosef", stub.ExpectArgs{"starting initial program %s", []any{check.MustAbs("/bin/zsh")}}, nil, nil),
 				call("start", stub.ExpectArgs{"/bin/zsh", []string{"zsh", "-c", "exec vim"}, []string{"DISPLAY=:0"}, "/.hakurei"}, &os.Process{Pid: 0xcafe}, nil),
-				call("printf", stub.ExpectArgs{"cannot close setup pipe: %v", []any{stub.UniqueError(0)}}, nil, nil),
 				call("New", stub.ExpectArgs{}, nil, nil),
 				call("notify", stub.ExpectArgs{nil, []os.Signal{CancelSignal, os.Interrupt, syscall.SIGTERM, syscall.SIGQUIT}}, nil, nil),
 				call("verbose", stub.ExpectArgs{[]any{os.ErrInvalid.Error()}}, nil, nil),

test/sandbox/test.py

@@ -45,6 +45,12 @@ machine.wait_for_file("/tmp/sway-ipc.sock")
 swaymsg("exec hakurei run cat")
 check_filter(0, "pdlike", "cat")
 
+# Check fd leak:
+swaymsg("exec hakurei -v run sleep infinity")
+pd_identity0_sleep_pid = int(machine.wait_until_succeeds("pgrep -U 10000 -x sleep", timeout=60))
+print(machine.succeed(f"hakurei-test fd {pd_identity0_sleep_pid}"))
+machine.succeed(f"kill -INT {pd_identity0_sleep_pid}")
+
 # Verify capabilities/securebits in user namespace:
 print(machine.succeed("sudo -u alice -i hakurei run capsh --print"))
 print(machine.succeed("sudo -u alice -i hakurei run capsh --has-no-new-privs"))

test/sandbox/tool/main.go

@@ -67,6 +67,39 @@ func main() {
 	case "hash": // this eases the pain of passing the hash to python
 		fmt.Print(flagBpfHash)
 
+	case "fd":
+		if len(args) != 2 {
+			log.Fatal("invalid argument")
+		}
+		prefix := fmt.Sprintf("/proc/%s/fd/", args[1])
+
+		var fail bool
+		if entries, err := os.ReadDir(prefix); err != nil {
+			log.Fatal(err.Error())
+		} else {
+			for _, ent := range entries {
+				var fd int
+				if fd, err = strconv.Atoi(ent.Name()); err != nil {
+					log.Fatal(err.Error())
+				}
+
+				// skip standard streams
+				if fd <= 2 {
+					continue
+				}
+				fail = true
+
+				var d string
+				if d, err = os.Readlink(prefix + ent.Name()); err != nil {
+					log.Fatal(err.Error())
+				}
+				log.Printf("[FAIL] extra fd %d -> %s", fd, d)
+			}
+		}
+		if fail {
+			log.Fatal("[FAIL] file descriptors leaked")
+		}
+
 	default:
 		log.Fatal("invalid argument")
 	}