internal/wayland: check pathname size

This avoids passing a truncated pathname to the kernel.

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

internal/wayland/wayland_test.go

@@ -1,12 +1,13 @@
-package wayland_test
+package wayland
 
 import (
+	"errors"
 	"os"
+	"reflect"
 	"syscall"
 	"testing"
 
 	"hakurei.app/container/stub"
-	"hakurei.app/internal/wayland"
 )
 
 func TestError(t *testing.T) {
@@ -14,88 +15,88 @@ func TestError(t *testing.T) {
 
 	testCases := []struct {
 		name string
-		err  wayland.Error
+		err  Error
 		want string
 	}{
-		{"success", wayland.Error{
-			Cause: wayland.RSuccess,
+		{"success", Error{
+			Cause: RSuccess,
 		}, "success"},
 
-		{"success errno", wayland.Error{
-			Cause: wayland.RSuccess,
+		{"success errno", Error{
+			Cause: RSuccess,
 			Errno: stub.UniqueError(0),
 		}, "unique error 0 injected by the test suite"},
 
-		{"wl_display_connect_to_fd", wayland.Error{
-			Cause: wayland.RConnect,
+		{"wl_display_connect_to_fd", Error{
+			Cause: RConnect,
 			Errno: stub.UniqueError(1),
 		}, "wl_display_connect_to_fd failed: unique error 1 injected by the test suite"},
 
-		{"wl_registry_add_listener", wayland.Error{
-			Cause: wayland.RListener,
+		{"wl_registry_add_listener", Error{
+			Cause: RListener,
 			Errno: stub.UniqueError(2),
 		}, "wl_registry_add_listener failed: unique error 2 injected by the test suite"},
 
-		{"wl_display_roundtrip", wayland.Error{
-			Cause: wayland.RRoundtrip,
+		{"wl_display_roundtrip", Error{
+			Cause: RRoundtrip,
 			Errno: stub.UniqueError(3),
 		}, "wl_display_roundtrip failed: unique error 3 injected by the test suite"},
 
-		{"not available", wayland.Error{
-			Cause: wayland.RNotAvail,
+		{"not available", Error{
+			Cause: RNotAvail,
 		}, "compositor does not implement security_context_v1"},
 
-		{"not available errno", wayland.Error{
-			Cause: wayland.RNotAvail,
+		{"not available errno", Error{
+			Cause: RNotAvail,
 			Errno: syscall.EAGAIN,
 		}, "compositor does not implement security_context_v1"},
 
-		{"socket", wayland.Error{
-			Cause: wayland.RSocket,
+		{"socket", Error{
+			Cause: RSocket,
 			Errno: stub.UniqueError(4),
 		}, "socket: unique error 4 injected by the test suite"},
 
-		{"bind", wayland.Error{
-			Cause: wayland.RBind,
+		{"bind", Error{
+			Cause: RBind,
 			Path:  "/hakurei.0/18783d07791f2460dbbcffb76c24c9e6/wayland",
 			Errno: stub.UniqueError(5),
 		}, "cannot bind /hakurei.0/18783d07791f2460dbbcffb76c24c9e6/wayland: unique error 5 injected by the test suite"},
 
-		{"listen", wayland.Error{
-			Cause: wayland.RListen,
+		{"listen", Error{
+			Cause: RListen,
 			Path:  "/hakurei.0/18783d07791f2460dbbcffb76c24c9e6/wayland",
 			Errno: stub.UniqueError(6),
 		}, "cannot listen on /hakurei.0/18783d07791f2460dbbcffb76c24c9e6/wayland: unique error 6 injected by the test suite"},
 
-		{"socket invalid", wayland.Error{
-			Cause: wayland.RSocket,
+		{"socket invalid", Error{
+			Cause: RSocket,
 		}, "socket operation failed"},
 
-		{"create", wayland.Error{
-			Cause: wayland.RCreate,
+		{"create", Error{
+			Cause: RCreate,
 		}, "cannot ensure wayland pathname socket"},
 
-		{"create path", wayland.Error{
-			Cause: wayland.RCreate,
+		{"create path", Error{
+			Cause: RCreate,
 			Errno: &os.PathError{Op: "create", Path: "/proc/nonexistent", Err: syscall.EEXIST},
 		}, "create /proc/nonexistent: file exists"},
 
-		{"host socket", wayland.Error{
-			Cause: wayland.RHostSocket,
+		{"host socket", Error{
+			Cause: RHostSocket,
 			Errno: stub.UniqueError(7),
 		}, "socket: unique error 7 injected by the test suite"},
 
-		{"host connect", wayland.Error{
-			Cause: wayland.RHostConnect,
+		{"host connect", Error{
+			Cause: RHostConnect,
 			Host:  "/run/user/1971/wayland-1",
 			Errno: stub.UniqueError(8),
 		}, "cannot connect to /run/user/1971/wayland-1: unique error 8 injected by the test suite"},
 
-		{"invalid", wayland.Error{
+		{"invalid", Error{
 			Cause: 0xbad,
 		}, "impossible outcome"},
 
-		{"invalid errno", wayland.Error{
+		{"invalid errno", Error{
 			Cause: 0xbad,
 			Errno: stub.UniqueError(9),
 		}, "impossible outcome: unique error 9 injected by the test suite"},
@@ -110,3 +111,27 @@ func TestError(t *testing.T) {
 		})
 	}
 }
+
+func TestSecurityContextBindValidate(t *testing.T) {
+	t.Parallel()
+
+	t.Run("NUL", func(t *testing.T) {
+		t.Parallel()
+
+		want := &Error{Cause: RBind, Path: "\x00", Errno: errors.New("argument contains NUL character")}
+		if got := securityContextBind("\x00", -1, "\x00", "\x00", -1); !reflect.DeepEqual(got, want) {
+			t.Fatalf("securityContextBind: error = %#v, want %#v", got, want)
+		}
+	})
+
+	t.Run("long", func(t *testing.T) {
+		t.Parallel()
+		// 256 bytes
+		const oversizedPath = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+
+		want := &Error{Cause: RBind, Path: oversizedPath, Errno: errors.New("socket pathname too long")}
+		if got := securityContextBind(oversizedPath, -1, "", "", -1); !reflect.DeepEqual(got, want) {
+			t.Fatalf("securityContextBind: error = %#v, want %#v", got, want)
+		}
+	})
+}