package archive // import "github.com/docker/docker/pkg/archive" import ( "os" "path/filepath" "syscall" "testing" "github.com/containerd/containerd/pkg/userns" "github.com/docker/docker/pkg/system" "golang.org/x/sys/unix" "gotest.tools/v3/assert" "gotest.tools/v3/skip" ) // setupOverlayTestDir creates files in a directory with overlay whiteouts // Tree layout // // . // ├── d1 # opaque, 0700 // │ └── f1 # empty file, 0600 // ├── d2 # opaque, 0750 // │ └── f1 # empty file, 0660 // └── d3 # 0700 // └── f1 # whiteout, 0644 func setupOverlayTestDir(t *testing.T, src string) { skip.If(t, os.Getuid() != 0, "skipping test that requires root") skip.If(t, userns.RunningInUserNS(), "skipping test that requires initial userns (trusted.overlay.opaque xattr cannot be set in userns, even with Ubuntu kernel)") // Create opaque directory containing single file and permission 0700 err := os.Mkdir(filepath.Join(src, "d1"), 0700) assert.NilError(t, err) err = system.Lsetxattr(filepath.Join(src, "d1"), "trusted.overlay.opaque", []byte("y"), 0) assert.NilError(t, err) err = os.WriteFile(filepath.Join(src, "d1", "f1"), []byte{}, 0600) assert.NilError(t, err) // Create another opaque directory containing single file but with permission 0750 err = os.Mkdir(filepath.Join(src, "d2"), 0750) assert.NilError(t, err) err = system.Lsetxattr(filepath.Join(src, "d2"), "trusted.overlay.opaque", []byte("y"), 0) assert.NilError(t, err) err = os.WriteFile(filepath.Join(src, "d2", "f1"), []byte{}, 0660) assert.NilError(t, err) // Create regular directory with deleted file err = os.Mkdir(filepath.Join(src, "d3"), 0700) assert.NilError(t, err) err = system.Mknod(filepath.Join(src, "d3", "f1"), unix.S_IFCHR, 0) assert.NilError(t, err) } func checkOpaqueness(t *testing.T, path string, opaque string) { xattrOpaque, err := system.Lgetxattr(path, "trusted.overlay.opaque") assert.NilError(t, err) if string(xattrOpaque) != opaque { t.Fatalf("Unexpected opaque value: %q, expected %q", string(xattrOpaque), opaque) } } func checkOverlayWhiteout(t *testing.T, path string) { stat, err := os.Stat(path) assert.NilError(t, err) statT, ok := stat.Sys().(*syscall.Stat_t) if !ok { t.Fatalf("Unexpected type: %t, expected *syscall.Stat_t", stat.Sys()) } if statT.Rdev != 0 { t.Fatalf("Non-zero device number for whiteout") } } func checkFileMode(t *testing.T, path string, perm os.FileMode) { stat, err := os.Stat(path) assert.NilError(t, err) if stat.Mode() != perm { t.Fatalf("Unexpected file mode for %s: %o, expected %o", path, stat.Mode(), perm) } } func TestOverlayTarUntar(t *testing.T) { oldmask, err := system.Umask(0) assert.NilError(t, err) defer system.Umask(oldmask) src, err := os.MkdirTemp("", "docker-test-overlay-tar-src") assert.NilError(t, err) defer os.RemoveAll(src) setupOverlayTestDir(t, src) dst, err := os.MkdirTemp("", "docker-test-overlay-tar-dst") assert.NilError(t, err) defer os.RemoveAll(dst) options := &TarOptions{ Compression: Uncompressed, WhiteoutFormat: OverlayWhiteoutFormat, } archive, err := TarWithOptions(src, options) assert.NilError(t, err) defer archive.Close() err = Untar(archive, dst, options) assert.NilError(t, err) checkFileMode(t, filepath.Join(dst, "d1"), 0700|os.ModeDir) checkFileMode(t, filepath.Join(dst, "d2"), 0750|os.ModeDir) checkFileMode(t, filepath.Join(dst, "d3"), 0700|os.ModeDir) checkFileMode(t, filepath.Join(dst, "d1", "f1"), 0600) checkFileMode(t, filepath.Join(dst, "d2", "f1"), 0660) checkFileMode(t, filepath.Join(dst, "d3", "f1"), os.ModeCharDevice|os.ModeDevice) checkOpaqueness(t, filepath.Join(dst, "d1"), "y") checkOpaqueness(t, filepath.Join(dst, "d2"), "y") checkOpaqueness(t, filepath.Join(dst, "d3"), "") checkOverlayWhiteout(t, filepath.Join(dst, "d3", "f1")) } func TestOverlayTarAUFSUntar(t *testing.T) { oldmask, err := system.Umask(0) assert.NilError(t, err) defer system.Umask(oldmask) src, err := os.MkdirTemp("", "docker-test-overlay-tar-src") assert.NilError(t, err) defer os.RemoveAll(src) setupOverlayTestDir(t, src) dst, err := os.MkdirTemp("", "docker-test-overlay-tar-dst") assert.NilError(t, err) defer os.RemoveAll(dst) archive, err := TarWithOptions(src, &TarOptions{ Compression: Uncompressed, WhiteoutFormat: OverlayWhiteoutFormat, }) assert.NilError(t, err) defer archive.Close() err = Untar(archive, dst, &TarOptions{ Compression: Uncompressed, WhiteoutFormat: AUFSWhiteoutFormat, }) assert.NilError(t, err) checkFileMode(t, filepath.Join(dst, "d1"), 0700|os.ModeDir) checkFileMode(t, filepath.Join(dst, "d1", WhiteoutOpaqueDir), 0700) checkFileMode(t, filepath.Join(dst, "d2"), 0750|os.ModeDir) checkFileMode(t, filepath.Join(dst, "d2", WhiteoutOpaqueDir), 0750) checkFileMode(t, filepath.Join(dst, "d3"), 0700|os.ModeDir) checkFileMode(t, filepath.Join(dst, "d1", "f1"), 0600) checkFileMode(t, filepath.Join(dst, "d2", "f1"), 0660) checkFileMode(t, filepath.Join(dst, "d3", WhiteoutPrefix+"f1"), 0600) }