// hasOpaqueCopyUpBug checks whether the filesystem has a bug
// which copies up the opaque flag when copying up an opaque
// directory. When this bug exists naive diff should be used.
func hasOpaqueCopyUpBug(d string) error {
td, err := ioutil.TempDir(d, "opaque-bug-check")
if err != nil {
return err
}
defer func() {
if err := os.RemoveAll(td); err != nil {
logrus.Warnf("Failed to remove check directory %v: %v", td, err)
}
}()
// Make directories l1/d, l2/d, l3, work, merged
if err := os.MkdirAll(filepath.Join(td, "l1", "d"), 0755); err != nil {
return err
}
if err := os.MkdirAll(filepath.Join(td, "l2", "d"), 0755); err != nil {
return err
}
if err := os.Mkdir(filepath.Join(td, "l3"), 0755); err != nil {
return err
}
if err := os.Mkdir(filepath.Join(td, "work"), 0755); err != nil {
return err
}
if err := os.Mkdir(filepath.Join(td, "merged"), 0755); err != nil {
return err
}
// Mark l2/d as opaque
if err := system.Lsetxattr(filepath.Join(td, "l2", "d"), "trusted.overlay.opaque", []byte("y"), 0); err != nil {
return errors.Wrap(err, "failed to set opaque flag on middle layer")
}
opts := fmt.Sprintf("lowerdir=%s:%s,upperdir=%s,workdir=%s", path.Join(td, "l2"), path.Join(td, "l1"), path.Join(td, "l3"), path.Join(td, "work"))
if err := syscall.Mount("overlay", filepath.Join(td, "merged"), "overlay", 0, opts); err != nil {
return errors.Wrap(err, "failed to mount overlay")
}
defer func() {
if err := syscall.Unmount(filepath.Join(td, "merged"), 0); err != nil {
logrus.Warnf("Failed to unmount check directory %v: %v", filepath.Join(td, "merged"), err)
}
}()
// Touch file in d to force copy up of opaque directory "d" from "l2" to "l3"
if err := ioutil.WriteFile(filepath.Join(td, "merged", "d", "f"), []byte{}, 0644); err != nil {
return errors.Wrap(err, "failed to write to merged directory")
}
// Check l3/d does not have opaque flag
xattrOpaque, err := system.Lgetxattr(filepath.Join(td, "l3", "d"), "trusted.overlay.opaque")
if err != nil {
return errors.Wrap(err, "failed to read opaque flag on upper layer")
}
if string(xattrOpaque) == "y" {
return errors.New("opaque flag erroneously copied up, consider update to kernel 4.8 or later to fix")
}
return nil
}
func copyXattr(srcPath, dstPath, attr string) error {
data, err := system.Lgetxattr(srcPath, attr)
if err != nil {
return err
}
if data != nil {
if err := system.Lsetxattr(dstPath, attr, data, 0); err != nil {
return err
}
}
return nil
}
// 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) {
// Create opaque directory containing single file and permission 0700
if err := os.Mkdir(filepath.Join(src, "d1"), 0700); err != nil {
t.Fatal(err)
}
if err := system.Lsetxattr(filepath.Join(src, "d1"), "trusted.overlay.opaque", []byte("y"), 0); err != nil {
t.Fatal(err)
}
if err := ioutil.WriteFile(filepath.Join(src, "d1", "f1"), []byte{}, 0600); err != nil {
t.Fatal(err)
}
// Create another opaque directory containing single file but with permission 0750
if err := os.Mkdir(filepath.Join(src, "d2"), 0750); err != nil {
t.Fatal(err)
}
if err := system.Lsetxattr(filepath.Join(src, "d2"), "trusted.overlay.opaque", []byte("y"), 0); err != nil {
t.Fatal(err)
}
if err := ioutil.WriteFile(filepath.Join(src, "d2", "f1"), []byte{}, 0660); err != nil {
t.Fatal(err)
}
// Create regular directory with deleted file
if err := os.Mkdir(filepath.Join(src, "d3"), 0700); err != nil {
t.Fatal(err)
}
if err := system.Mknod(filepath.Join(src, "d3", "f1"), syscall.S_IFCHR, 0); err != nil {
t.Fatal(err)
}
}
// TestTarUntarWithXattr is Unix as Lsetxattr is not supported on Windows
func TestTarUntarWithXattr(t *testing.T) {
if runtime.GOOS == "solaris" {
t.Skip()
}
origin, err := ioutil.TempDir("", "docker-test-untar-origin")
if err != nil {
t.Fatal(err)
}
defer os.RemoveAll(origin)
if err := ioutil.WriteFile(filepath.Join(origin, "1"), []byte("hello world"), 0700); err != nil {
t.Fatal(err)
}
if err := ioutil.WriteFile(filepath.Join(origin, "2"), []byte("welcome!"), 0700); err != nil {
t.Fatal(err)
}
if err := ioutil.WriteFile(filepath.Join(origin, "3"), []byte("will be ignored"), 0700); err != nil {
t.Fatal(err)
}
if err := system.Lsetxattr(filepath.Join(origin, "2"), "security.capability", []byte{0x00}, 0); err != nil {
t.Fatal(err)
}
for _, c := range []Compression{
Uncompressed,
Gzip,
} {
changes, err := tarUntar(t, origin, &TarOptions{
Compression: c,
ExcludePatterns: []string{"3"},
})
if err != nil {
t.Fatalf("Error tar/untar for compression %s: %s", c.Extension(), err)
}
if len(changes) != 1 || changes[0].Path != "/3" {
t.Fatalf("Unexpected differences after tarUntar: %v", changes)
}
capability, _ := system.Lgetxattr(filepath.Join(origin, "2"), "security.capability")
if capability == nil && capability[0] != 0x00 {
t.Fatalf("Untar should have kept the 'security.capability' xattr.")
}
}
}
func createTarFile(path, extractDir string, hdr *tar.Header, reader io.Reader, Lchown bool) error {
// hdr.Mode is in linux format, which we can use for sycalls,
// but for os.Foo() calls we need the mode converted to os.FileMode,
// so use hdrInfo.Mode() (they differ for e.g. setuid bits)
hdrInfo := hdr.FileInfo()
switch hdr.Typeflag {
case tar.TypeDir:
// Create directory unless it exists as a directory already.
// In that case we just want to merge the two
if fi, err := os.Lstat(path); !(err == nil && fi.IsDir()) {
if err := os.Mkdir(path, hdrInfo.Mode()); err != nil {
return err
}
}
case tar.TypeReg, tar.TypeRegA:
// Source is regular file
file, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY, hdrInfo.Mode())
if err != nil {
return err
}
if _, err := io.Copy(file, reader); err != nil {
file.Close()
return err
}
file.Close()
case tar.TypeBlock, tar.TypeChar, tar.TypeFifo:
mode := uint32(hdr.Mode & 07777)
switch hdr.Typeflag {
case tar.TypeBlock:
mode |= syscall.S_IFBLK
case tar.TypeChar:
mode |= syscall.S_IFCHR
case tar.TypeFifo:
mode |= syscall.S_IFIFO
}
if err := syscall.Mknod(path, mode, int(mkdev(hdr.Devmajor, hdr.Devminor))); err != nil {
return err
}
case tar.TypeLink:
targetPath := filepath.Join(extractDir, hdr.Linkname)
// check for hardlink breakout
if !strings.HasPrefix(targetPath, extractDir) {
return breakoutError(fmt.Errorf("invalid hardlink %q -> %q", targetPath, hdr.Linkname))
}
if err := os.Link(targetPath, path); err != nil {
return err
}
case tar.TypeSymlink:
// path -> hdr.Linkname = targetPath
// e.g. /extractDir/path/to/symlink -> ../2/file = /extractDir/path/2/file
targetPath := filepath.Join(filepath.Dir(path), hdr.Linkname)
// the reason we don't need to check symlinks in the path (with FollowSymlinkInScope) is because
// that symlink would first have to be created, which would be caught earlier, at this very check:
if !strings.HasPrefix(targetPath, extractDir) {
return breakoutError(fmt.Errorf("invalid symlink %q -> %q", path, hdr.Linkname))
}
if err := os.Symlink(hdr.Linkname, path); err != nil {
return err
}
case tar.TypeXGlobalHeader:
log.Debugf("PAX Global Extended Headers found and ignored")
return nil
default:
return fmt.Errorf("Unhandled tar header type %d\n", hdr.Typeflag)
}
if err := os.Lchown(path, hdr.Uid, hdr.Gid); err != nil && Lchown {
return err
}
for key, value := range hdr.Xattrs {
if err := system.Lsetxattr(path, key, []byte(value), 0); err != nil {
return err
}
}
// There is no LChmod, so ignore mode for symlink. Also, this
// must happen after chown, as that can modify the file mode
if hdr.Typeflag != tar.TypeSymlink {
if err := os.Chmod(path, hdrInfo.Mode()); err != nil {
return err
}
}
ts := []syscall.Timespec{timeToTimespec(hdr.AccessTime), timeToTimespec(hdr.ModTime)}
// syscall.UtimesNano doesn't support a NOFOLLOW flag atm, and
if hdr.Typeflag != tar.TypeSymlink {
if err := system.UtimesNano(path, ts); err != nil && err != system.ErrNotSupportedPlatform {
return err
}
} else {
if err := system.LUtimesNano(path, ts); err != nil && err != system.ErrNotSupportedPlatform {
return err
}
}
return nil
}
func createTarFile(path, extractDir string, hdr *tar.Header, reader io.Reader, Lchown bool, chownOpts *TarChownOptions, inUserns bool) error {
// hdr.Mode is in linux format, which we can use for sycalls,
// but for os.Foo() calls we need the mode converted to os.FileMode,
// so use hdrInfo.Mode() (they differ for e.g. setuid bits)
hdrInfo := hdr.FileInfo()
switch hdr.Typeflag {
case tar.TypeDir:
// Create directory unless it exists as a directory already.
// In that case we just want to merge the two
if fi, err := os.Lstat(path); !(err == nil && fi.IsDir()) {
if err := os.Mkdir(path, hdrInfo.Mode()); err != nil {
return err
}
}
case tar.TypeReg, tar.TypeRegA:
// Source is regular file
file, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY, hdrInfo.Mode())
if err != nil {
return err
}
if _, err := io.Copy(file, reader); err != nil {
file.Close()
return err
}
file.Close()
case tar.TypeBlock, tar.TypeChar:
if inUserns { // cannot create devices in a userns
return nil
}
// Handle this is an OS-specific way
if err := handleTarTypeBlockCharFifo(hdr, path); err != nil {
return err
}
case tar.TypeFifo:
// Handle this is an OS-specific way
if err := handleTarTypeBlockCharFifo(hdr, path); err != nil {
return err
}
case tar.TypeLink:
targetPath := filepath.Join(extractDir, hdr.Linkname)
// check for hardlink breakout
if !strings.HasPrefix(targetPath, extractDir) {
return breakoutError(fmt.Errorf("invalid hardlink %q -> %q", targetPath, hdr.Linkname))
}
if err := os.Link(targetPath, path); err != nil {
return err
}
case tar.TypeSymlink:
// path -> hdr.Linkname = targetPath
// e.g. /extractDir/path/to/symlink -> ../2/file = /extractDir/path/2/file
targetPath := filepath.Join(filepath.Dir(path), hdr.Linkname)
// the reason we don't need to check symlinks in the path (with FollowSymlinkInScope) is because
// that symlink would first have to be created, which would be caught earlier, at this very check:
if !strings.HasPrefix(targetPath, extractDir) {
return breakoutError(fmt.Errorf("invalid symlink %q -> %q", path, hdr.Linkname))
}
if err := os.Symlink(hdr.Linkname, path); err != nil {
return err
}
case tar.TypeXGlobalHeader:
logrus.Debug("PAX Global Extended Headers found and ignored")
return nil
default:
return fmt.Errorf("Unhandled tar header type %d\n", hdr.Typeflag)
}
// Lchown is not supported on Windows.
if Lchown && runtime.GOOS != "windows" {
if chownOpts == nil {
chownOpts = &TarChownOptions{UID: hdr.Uid, GID: hdr.Gid}
}
if err := os.Lchown(path, chownOpts.UID, chownOpts.GID); err != nil {
return err
}
}
var errors []string
for key, value := range hdr.Xattrs {
if err := system.Lsetxattr(path, key, []byte(value), 0); err != nil {
if err == syscall.ENOTSUP {
// We ignore errors here because not all graphdrivers support
// xattrs *cough* old versions of AUFS *cough*. However only
// ENOTSUP should be emitted in that case, otherwise we still
// bail.
errors = append(errors, err.Error())
continue
}
return err
}
}
if len(errors) > 0 {
logrus.WithFields(logrus.Fields{
"errors": errors,
}).Warn("ignored xattrs in archive: underlying filesystem doesn't support them")
}
// There is no LChmod, so ignore mode for symlink. Also, this
// must happen after chown, as that can modify the file mode
if err := handleLChmod(hdr, path, hdrInfo); err != nil {
return err
}
aTime := hdr.AccessTime
if aTime.Before(hdr.ModTime) {
// Last access time should never be before last modified time.
aTime = hdr.ModTime
}
// system.Chtimes doesn't support a NOFOLLOW flag atm
if hdr.Typeflag == tar.TypeLink {
if fi, err := os.Lstat(hdr.Linkname); err == nil && (fi.Mode()&os.ModeSymlink == 0) {
if err := system.Chtimes(path, aTime, hdr.ModTime); err != nil {
return err
}
}
} else if hdr.Typeflag != tar.TypeSymlink {
if err := system.Chtimes(path, aTime, hdr.ModTime); err != nil {
return err
}
} else {
ts := []syscall.Timespec{timeToTimespec(aTime), timeToTimespec(hdr.ModTime)}
if err := system.LUtimesNano(path, ts); err != nil && err != system.ErrNotSupportedPlatform {
return err
}
}
return nil
}