overlay: Test user.fuseoverlayfs.override_stat handling

Signed-off-by: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>

drivers/graphtest/graphtest_unix.go

@@ -44,13 +44,7 @@ type Driver struct {
 	refCount int
 }
 
-func newDriver(t testing.TB, name string, options []string) *Driver {
-	root, err := os.MkdirTemp("", "storage-graphtest-")
-	require.NoError(t, err)
-	runroot, err := os.MkdirTemp("", "storage-graphtest-")
-	require.NoError(t, err)
-
-	require.NoError(t, os.MkdirAll(root, 0o755))
+func newGraphDriver(t testing.TB, name string, options []string, root string, runroot string) graphdriver.Driver {
 	d, err := graphdriver.GetDriver(name, graphdriver.Options{DriverOptions: options, Root: root, RunRoot: runroot})
 	if err != nil {
 		t.Logf("graphdriver: %v\n", err)
@@ -63,7 +57,17 @@ func newDriver(t testing.TB, name string, options []string) *Driver {
 		}
 		t.Fatal(err)
 	}
-	return &Driver{d, root, runroot, 1}
+	return d
+}
+
+func newDriver(t testing.TB, name string, options []string) *Driver {
+	root, err := os.MkdirTemp("", "storage-graphtest-")
+	require.NoError(t, err)
+	runroot, err := os.MkdirTemp("", "storage-graphtest-")
+	require.NoError(t, err)
+
+	require.NoError(t, os.MkdirAll(root, 0o755))
+	return &Driver{newGraphDriver(t, name, options, root, runroot), root, runroot, 1}
 }
 
 func cleanup(t testing.TB, d *Driver) {
@@ -84,6 +88,13 @@ func GetDriver(t testing.TB, name string, options ...string) graphdriver.Driver
 	return drv
 }
 
+func ReconfigureDriver(t testing.TB, name string, options ...string) {
+	if err := drv.Cleanup(); err != nil {
+		t.Fatal(err)
+	}
+	drv.Driver = newGraphDriver(t, name, options, drv.root, drv.runroot)
+}
+
 // PutDriver removes the driver if it is no longer used and updates the reference count.
 func PutDriver(t testing.TB) {
 	if drv == nil {

drivers/overlay/overlay_test.go

@@ -4,12 +4,16 @@
 package overlay
 
 import (
+	"os"
+	"os/exec"
 	"testing"
 
 	graphdriver "github.com/containers/storage/drivers"
 	"github.com/containers/storage/drivers/graphtest"
 	"github.com/containers/storage/pkg/archive"
 	"github.com/containers/storage/pkg/reexec"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 const driverName = "overlay"
@@ -31,6 +35,31 @@ func skipIfNaive(t *testing.T) {
 	}
 }
 
+// Ensure that a layer created with force_mask will keep the root directory mode
+// with user.containers.override_stat. This preserved mode should also be
+// inherited by the upper layer, whether force_mask is set or not.
+//
+// This test is placed before TestOverlaySetup() because it uses driver options
+// different from the other tests.
+func TestContainersOverlayXattr(t *testing.T) {
+	path, err := exec.LookPath("fuse-overlayfs")
+	if err != nil {
+		t.Skipf("fuse-overlayfs unavailable")
+	}
+
+	driver := graphtest.GetDriver(t, driverName, "force_mask=700", "mount_program="+path)
+	defer graphtest.PutDriver(t)
+	require.NoError(t, driver.Create("lower", "", nil))
+	graphtest.ReconfigureDriver(t, driverName, "mount_program="+path)
+	require.NoError(t, driver.Create("upper", "lower", nil))
+
+	root, err := driver.Get("upper", graphdriver.MountOpts{})
+	require.NoError(t, err)
+	fi, err := os.Stat(root)
+	require.NoError(t, err)
+	assert.Equal(t, 0o555&os.ModePerm, fi.Mode()&os.ModePerm, root)
+}
+
 // This avoids creating a new driver for each test if all tests are run
 // Make sure to put new tests between TestOverlaySetup and TestOverlayTeardown
 func TestOverlaySetup(t *testing.T) {