archive: do not use overlayWhiteoutConverter for UserNS
overlay2 no longer sets `archive.OverlayWhiteoutFormat` when running in UserNS, so we can remove the complicated logic in the archive package. Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
This commit is contained in:
Akihiro Suda
parent
67aa418df2
commit
6322dfc217
|
|
@ -15,7 +15,6 @@ import (
|
|||
"strings"
|
||||
"sync"
|
||||
|
||||
"github.com/containerd/containerd/sys"
|
||||
"github.com/docker/docker/daemon/graphdriver"
|
||||
"github.com/docker/docker/daemon/graphdriver/overlayutils"
|
||||
"github.com/docker/docker/pkg/archive"
|
||||
|
|
@ -682,6 +681,7 @@ func (d *Driver) ApplyDiff(id string, parent string, diff io.Reader) (size int64
|
|||
return d.naiveDiff.ApplyDiff(id, parent, diff)
|
||||
}
|
||||
|
||||
// never reach here if we are running in UserNS
|
||||
applyDir := d.getDiffPath(id)
|
||||
|
||||
logger.Debugf("Applying tar in %s", applyDir)
|
||||
|
|
@ -690,7 +690,6 @@ func (d *Driver) ApplyDiff(id string, parent string, diff io.Reader) (size int64
|
|||
UIDMaps: d.uidMaps,
|
||||
GIDMaps: d.gidMaps,
|
||||
WhiteoutFormat: archive.OverlayWhiteoutFormat,
|
||||
InUserNS: sys.RunningInUserNS(),
|
||||
}); err != nil {
|
||||
return 0, err
|
||||
}
|
||||
|
|
@ -721,6 +720,7 @@ func (d *Driver) Diff(id, parent string) (io.ReadCloser, error) {
|
|||
return d.naiveDiff.Diff(id, parent)
|
||||
}
|
||||
|
||||
// never reach here if we are running in UserNS
|
||||
diffPath := d.getDiffPath(id)
|
||||
logger.Debugf("Tar with options on %s", diffPath)
|
||||
return archive.TarWithOptions(diffPath, &archive.TarOptions{
|
||||
|
|
|
|||
|
|
@ -753,13 +753,18 @@ func TarWithOptions(srcPath string, options *TarOptions) (io.ReadCloser, error)
|
|||
return nil, err
|
||||
}
|
||||
|
||||
whiteoutConverter, err := getWhiteoutConverter(options.WhiteoutFormat, options.InUserNS)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
|
||||
go func() {
|
||||
ta := newTarAppender(
|
||||
idtools.NewIDMappingsFromMaps(options.UIDMaps, options.GIDMaps),
|
||||
compressWriter,
|
||||
options.ChownOpts,
|
||||
)
|
||||
ta.WhiteoutConverter = getWhiteoutConverter(options.WhiteoutFormat, options.InUserNS)
|
||||
ta.WhiteoutConverter = whiteoutConverter
|
||||
|
||||
defer func() {
|
||||
// Make sure to check the error on Close.
|
||||
|
|
@ -917,7 +922,10 @@ func Unpack(decompressedArchive io.Reader, dest string, options *TarOptions) err
|
|||
var dirs []*tar.Header
|
||||
idMapping := idtools.NewIDMappingsFromMaps(options.UIDMaps, options.GIDMaps)
|
||||
rootIDs := idMapping.RootPair()
|
||||
whiteoutConverter := getWhiteoutConverter(options.WhiteoutFormat, options.InUserNS)
|
||||
whiteoutConverter, err := getWhiteoutConverter(options.WhiteoutFormat, options.InUserNS)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
// Iterate through the files in the archive.
|
||||
loop:
|
||||
|
|
|
|||
|
|
@ -2,29 +2,26 @@ package archive // import "github.com/docker/docker/pkg/archive"
|
|||
|
||||
import (
|
||||
"archive/tar"
|
||||
"fmt"
|
||||
"io/ioutil"
|
||||
"os"
|
||||
"path/filepath"
|
||||
"strings"
|
||||
"syscall"
|
||||
|
||||
"github.com/containerd/continuity/fs"
|
||||
"github.com/docker/docker/pkg/system"
|
||||
"github.com/moby/sys/mount"
|
||||
"github.com/pkg/errors"
|
||||
"golang.org/x/sys/unix"
|
||||
)
|
||||
|
||||
func getWhiteoutConverter(format WhiteoutFormat, inUserNS bool) tarWhiteoutConverter {
|
||||
func getWhiteoutConverter(format WhiteoutFormat, inUserNS bool) (tarWhiteoutConverter, error) {
|
||||
if format == OverlayWhiteoutFormat {
|
||||
return overlayWhiteoutConverter{inUserNS: inUserNS}
|
||||
if inUserNS {
|
||||
return nil, errors.New("specifying OverlayWhiteoutFormat is not allowed in userns")
|
||||
}
|
||||
return overlayWhiteoutConverter{}, nil
|
||||
}
|
||||
return nil
|
||||
return nil, nil
|
||||
}
|
||||
|
||||
type overlayWhiteoutConverter struct {
|
||||
inUserNS bool
|
||||
}
|
||||
|
||||
func (overlayWhiteoutConverter) ConvertWrite(hdr *tar.Header, path string, fi os.FileInfo) (wo *tar.Header, err error) {
|
||||
|
|
@ -77,13 +74,7 @@ func (c overlayWhiteoutConverter) ConvertRead(hdr *tar.Header, path string) (boo
|
|||
if base == WhiteoutOpaqueDir {
|
||||
err := unix.Setxattr(dir, "trusted.overlay.opaque", []byte{'y'}, 0)
|
||||
if err != nil {
|
||||
if c.inUserNS {
|
||||
if err = replaceDirWithOverlayOpaque(dir); err != nil {
|
||||
return false, errors.Wrapf(err, "replaceDirWithOverlayOpaque(%q) failed", dir)
|
||||
}
|
||||
} else {
|
||||
return false, errors.Wrapf(err, "setxattr(%q, trusted.overlay.opaque=y)", dir)
|
||||
}
|
||||
return false, errors.Wrapf(err, "setxattr(%q, trusted.overlay.opaque=y)", dir)
|
||||
}
|
||||
// don't write the file itself
|
||||
return false, err
|
||||
|
|
@ -95,19 +86,7 @@ func (c overlayWhiteoutConverter) ConvertRead(hdr *tar.Header, path string) (boo
|
|||
originalPath := filepath.Join(dir, originalBase)
|
||||
|
||||
if err := unix.Mknod(originalPath, unix.S_IFCHR, 0); err != nil {
|
||||
if c.inUserNS {
|
||||
// Ubuntu and a few distros support overlayfs in userns.
|
||||
//
|
||||
// Although we can't call mknod directly in userns (at least on bionic kernel 4.15),
|
||||
// we can still create 0,0 char device using mknodChar0Overlay().
|
||||
//
|
||||
// NOTE: we don't need this hack for the containerd snapshotter+unpack model.
|
||||
if err := mknodChar0Overlay(originalPath); err != nil {
|
||||
return false, errors.Wrapf(err, "failed to mknodChar0UserNS(%q)", originalPath)
|
||||
}
|
||||
} else {
|
||||
return false, errors.Wrapf(err, "failed to mknod(%q, S_IFCHR, 0)", originalPath)
|
||||
}
|
||||
return false, errors.Wrapf(err, "failed to mknod(%q, S_IFCHR, 0)", originalPath)
|
||||
}
|
||||
if err := os.Chown(originalPath, hdr.Uid, hdr.Gid); err != nil {
|
||||
return false, err
|
||||
|
|
@ -119,146 +98,3 @@ func (c overlayWhiteoutConverter) ConvertRead(hdr *tar.Header, path string) (boo
|
|||
|
||||
return true, nil
|
||||
}
|
||||
|
||||
// mknodChar0Overlay creates 0,0 char device by mounting overlayfs and unlinking.
|
||||
// This function can be used for creating 0,0 char device in userns on Ubuntu.
|
||||
//
|
||||
// Steps:
|
||||
// * Mkdir lower,upper,merged,work
|
||||
// * Create lower/dummy
|
||||
// * Mount overlayfs
|
||||
// * Unlink merged/dummy
|
||||
// * Unmount overlayfs
|
||||
// * Make sure a 0,0 char device is created as upper/dummy
|
||||
// * Rename upper/dummy to cleansedOriginalPath
|
||||
func mknodChar0Overlay(cleansedOriginalPath string) error {
|
||||
dir := filepath.Dir(cleansedOriginalPath)
|
||||
tmp, err := ioutil.TempDir(dir, "mc0o")
|
||||
if err != nil {
|
||||
return errors.Wrapf(err, "failed to create a tmp directory under %s", dir)
|
||||
}
|
||||
defer os.RemoveAll(tmp)
|
||||
lower := filepath.Join(tmp, "l")
|
||||
upper := filepath.Join(tmp, "u")
|
||||
work := filepath.Join(tmp, "w")
|
||||
merged := filepath.Join(tmp, "m")
|
||||
for _, s := range []string{lower, upper, work, merged} {
|
||||
if err := os.MkdirAll(s, 0700); err != nil {
|
||||
return errors.Wrapf(err, "failed to mkdir %s", s)
|
||||
}
|
||||
}
|
||||
dummyBase := "d"
|
||||
lowerDummy := filepath.Join(lower, dummyBase)
|
||||
if err := ioutil.WriteFile(lowerDummy, []byte{}, 0600); err != nil {
|
||||
return errors.Wrapf(err, "failed to create a dummy lower file %s", lowerDummy)
|
||||
}
|
||||
// lowerdir needs ":" to be escaped: https://github.com/moby/moby/issues/40939#issuecomment-627098286
|
||||
lowerEscaped := strings.ReplaceAll(lower, ":", "\\:")
|
||||
mOpts := fmt.Sprintf("lowerdir=%s,upperdir=%s,workdir=%s", lowerEscaped, upper, work)
|
||||
if err := mount.Mount("overlay", merged, "overlay", mOpts); err != nil {
|
||||
return err
|
||||
}
|
||||
mergedDummy := filepath.Join(merged, dummyBase)
|
||||
if err := os.Remove(mergedDummy); err != nil {
|
||||
syscall.Unmount(merged, 0)
|
||||
return errors.Wrapf(err, "failed to unlink %s", mergedDummy)
|
||||
}
|
||||
if err := syscall.Unmount(merged, 0); err != nil {
|
||||
return errors.Wrapf(err, "failed to unmount %s", merged)
|
||||
}
|
||||
upperDummy := filepath.Join(upper, dummyBase)
|
||||
if err := isChar0(upperDummy); err != nil {
|
||||
return err
|
||||
}
|
||||
if err := os.Rename(upperDummy, cleansedOriginalPath); err != nil {
|
||||
return errors.Wrapf(err, "failed to rename %s to %s", upperDummy, cleansedOriginalPath)
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
func isChar0(path string) error {
|
||||
osStat, err := os.Stat(path)
|
||||
if err != nil {
|
||||
return errors.Wrapf(err, "failed to stat %s", path)
|
||||
}
|
||||
st, ok := osStat.Sys().(*syscall.Stat_t)
|
||||
if !ok {
|
||||
return errors.Errorf("got unsupported stat for %s", path)
|
||||
}
|
||||
if os.FileMode(st.Mode)&syscall.S_IFMT != syscall.S_IFCHR {
|
||||
return errors.Errorf("%s is not a character device, got mode=%d", path, st.Mode)
|
||||
}
|
||||
if st.Rdev != 0 {
|
||||
return errors.Errorf("%s is not a 0,0 character device, got Rdev=%d", path, st.Rdev)
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
// replaceDirWithOverlayOpaque replaces path with a new directory with trusted.overlay.opaque
|
||||
// xattr. The contents of the directory are preserved.
|
||||
func replaceDirWithOverlayOpaque(path string) error {
|
||||
if path == "/" {
|
||||
return errors.New("replaceDirWithOverlayOpaque: path must not be \"/\"")
|
||||
}
|
||||
dir := filepath.Dir(path)
|
||||
tmp, err := ioutil.TempDir(dir, "rdwoo")
|
||||
if err != nil {
|
||||
return errors.Wrapf(err, "failed to create a tmp directory under %s", dir)
|
||||
}
|
||||
defer os.RemoveAll(tmp)
|
||||
// newPath is a new empty directory crafted with trusted.overlay.opaque xattr.
|
||||
// we copy the content of path into newPath, remove path, and rename newPath to path.
|
||||
newPath, err := createDirWithOverlayOpaque(tmp)
|
||||
if err != nil {
|
||||
return errors.Wrapf(err, "createDirWithOverlayOpaque(%q) failed", tmp)
|
||||
}
|
||||
if err := fs.CopyDir(newPath, path); err != nil {
|
||||
return errors.Wrapf(err, "CopyDir(%q, %q) failed", newPath, path)
|
||||
}
|
||||
if err := os.RemoveAll(path); err != nil {
|
||||
return err
|
||||
}
|
||||
return os.Rename(newPath, path)
|
||||
}
|
||||
|
||||
// createDirWithOverlayOpaque creates a directory with trusted.overlay.opaque xattr,
|
||||
// without calling setxattr, so as to allow creating opaque dir in userns on Ubuntu.
|
||||
func createDirWithOverlayOpaque(tmp string) (string, error) {
|
||||
lower := filepath.Join(tmp, "l")
|
||||
upper := filepath.Join(tmp, "u")
|
||||
work := filepath.Join(tmp, "w")
|
||||
merged := filepath.Join(tmp, "m")
|
||||
for _, s := range []string{lower, upper, work, merged} {
|
||||
if err := os.MkdirAll(s, 0700); err != nil {
|
||||
return "", errors.Wrapf(err, "failed to mkdir %s", s)
|
||||
}
|
||||
}
|
||||
dummyBase := "d"
|
||||
lowerDummy := filepath.Join(lower, dummyBase)
|
||||
if err := os.MkdirAll(lowerDummy, 0700); err != nil {
|
||||
return "", errors.Wrapf(err, "failed to create a dummy lower directory %s", lowerDummy)
|
||||
}
|
||||
// lowerdir needs ":" to be escaped: https://github.com/moby/moby/issues/40939#issuecomment-627098286
|
||||
lowerEscaped := strings.ReplaceAll(lower, ":", "\\:")
|
||||
mOpts := fmt.Sprintf("lowerdir=%s,upperdir=%s,workdir=%s", lowerEscaped, upper, work)
|
||||
if err := mount.Mount("overlay", merged, "overlay", mOpts); err != nil {
|
||||
return "", err
|
||||
}
|
||||
mergedDummy := filepath.Join(merged, dummyBase)
|
||||
if err := os.Remove(mergedDummy); err != nil {
|
||||
syscall.Unmount(merged, 0)
|
||||
return "", errors.Wrapf(err, "failed to rmdir %s", mergedDummy)
|
||||
}
|
||||
// upperDummy becomes a 0,0-char device file here
|
||||
if err := os.Mkdir(mergedDummy, 0700); err != nil {
|
||||
syscall.Unmount(merged, 0)
|
||||
return "", errors.Wrapf(err, "failed to mkdir %s", mergedDummy)
|
||||
}
|
||||
// upperDummy becomes a directory with trusted.overlay.opaque xattr
|
||||
// (but can't be verified in userns)
|
||||
if err := syscall.Unmount(merged, 0); err != nil {
|
||||
return "", errors.Wrapf(err, "failed to unmount %s", merged)
|
||||
}
|
||||
upperDummy := filepath.Join(upper, dummyBase)
|
||||
return upperDummy, nil
|
||||
}
|
||||
|
|
|
|||
|
|
@ -1,19 +1,14 @@
|
|||
package archive // import "github.com/docker/docker/pkg/archive"
|
||||
|
||||
import (
|
||||
"fmt"
|
||||
"io/ioutil"
|
||||
"os"
|
||||
"os/exec"
|
||||
"path/filepath"
|
||||
"syscall"
|
||||
"testing"
|
||||
|
||||
"github.com/containerd/containerd/sys"
|
||||
"github.com/docker/docker/pkg/reexec"
|
||||
"github.com/docker/docker/pkg/system"
|
||||
"github.com/moby/sys/mount"
|
||||
"github.com/pkg/errors"
|
||||
"golang.org/x/sys/unix"
|
||||
"gotest.tools/v3/assert"
|
||||
"gotest.tools/v3/skip"
|
||||
|
|
@ -167,129 +162,3 @@ func TestOverlayTarAUFSUntar(t *testing.T) {
|
|||
checkFileMode(t, filepath.Join(dst, "d2", "f1"), 0660)
|
||||
checkFileMode(t, filepath.Join(dst, "d3", WhiteoutPrefix+"f1"), 0600)
|
||||
}
|
||||
|
||||
func unshareCmd(cmd *exec.Cmd) {
|
||||
cmd.SysProcAttr = &syscall.SysProcAttr{
|
||||
Cloneflags: syscall.CLONE_NEWUSER | syscall.CLONE_NEWNS,
|
||||
UidMappings: []syscall.SysProcIDMap{
|
||||
{
|
||||
ContainerID: 0,
|
||||
HostID: os.Geteuid(),
|
||||
Size: 1,
|
||||
},
|
||||
},
|
||||
GidMappings: []syscall.SysProcIDMap{
|
||||
{
|
||||
ContainerID: 0,
|
||||
HostID: os.Getegid(),
|
||||
Size: 1,
|
||||
},
|
||||
},
|
||||
}
|
||||
}
|
||||
|
||||
const (
|
||||
reexecSupportsUserNSOverlay = "docker-test-supports-userns-overlay"
|
||||
reexecMknodChar0 = "docker-test-userns-mknod-char0"
|
||||
reexecSetOpaque = "docker-test-userns-set-opaque"
|
||||
)
|
||||
|
||||
func supportsOverlay(dir string) error {
|
||||
lower := filepath.Join(dir, "l")
|
||||
upper := filepath.Join(dir, "u")
|
||||
work := filepath.Join(dir, "w")
|
||||
merged := filepath.Join(dir, "m")
|
||||
for _, s := range []string{lower, upper, work, merged} {
|
||||
if err := os.MkdirAll(s, 0700); err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
mOpts := fmt.Sprintf("lowerdir=%s,upperdir=%s,workdir=%s", lower, upper, work)
|
||||
if err := mount.Mount("overlay", merged, "overlay", mOpts); err != nil {
|
||||
return err
|
||||
}
|
||||
if err := mount.Unmount(merged); err != nil {
|
||||
return err
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
// supportsUserNSOverlay returns nil error if overlay is supported in userns.
|
||||
// Only Ubuntu and a few distros support overlay in userns (by patching the kernel).
|
||||
// https://lists.ubuntu.com/archives/kernel-team/2014-February/038091.html
|
||||
// As of kernel 4.19, the patch is not merged to the upstream.
|
||||
func supportsUserNSOverlay() error {
|
||||
tmp, err := ioutil.TempDir("", "docker-test-supports-userns-overlay")
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
defer os.RemoveAll(tmp)
|
||||
cmd := reexec.Command(reexecSupportsUserNSOverlay, tmp)
|
||||
unshareCmd(cmd)
|
||||
out, err := cmd.CombinedOutput()
|
||||
if err != nil {
|
||||
return errors.Wrapf(err, "output: %q", string(out))
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
// isOpaque returns nil error if the dir has trusted.overlay.opaque=y.
|
||||
// isOpaque needs to be called in the initial userns.
|
||||
func isOpaque(dir string) error {
|
||||
xattrOpaque, err := system.Lgetxattr(dir, "trusted.overlay.opaque")
|
||||
if err != nil {
|
||||
return errors.Wrapf(err, "failed to read opaque flag of %s", dir)
|
||||
}
|
||||
if string(xattrOpaque) != "y" {
|
||||
return errors.Errorf("expected \"y\", got %q", string(xattrOpaque))
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
func TestReexecUserNSOverlayWhiteoutConverter(t *testing.T) {
|
||||
skip.If(t, os.Getuid() != 0, "skipping test that requires root")
|
||||
skip.If(t, sys.RunningInUserNS(), "skipping test that requires initial userns")
|
||||
if err := supportsUserNSOverlay(); err != nil {
|
||||
t.Skipf("skipping test that requires kernel support for overlay-in-userns: %v", err)
|
||||
}
|
||||
tmp, err := ioutil.TempDir("", "docker-test-userns-overlay")
|
||||
assert.NilError(t, err)
|
||||
defer os.RemoveAll(tmp)
|
||||
|
||||
char0 := filepath.Join(tmp, "char0")
|
||||
cmd := reexec.Command(reexecMknodChar0, char0)
|
||||
unshareCmd(cmd)
|
||||
out, err := cmd.CombinedOutput()
|
||||
assert.NilError(t, err, string(out))
|
||||
assert.NilError(t, isChar0(char0))
|
||||
|
||||
opaqueDir := filepath.Join(tmp, "opaquedir")
|
||||
err = os.MkdirAll(opaqueDir, 0755)
|
||||
assert.NilError(t, err, string(out))
|
||||
cmd = reexec.Command(reexecSetOpaque, opaqueDir)
|
||||
unshareCmd(cmd)
|
||||
out, err = cmd.CombinedOutput()
|
||||
assert.NilError(t, err, string(out))
|
||||
assert.NilError(t, isOpaque(opaqueDir))
|
||||
}
|
||||
|
||||
func init() {
|
||||
reexec.Register(reexecSupportsUserNSOverlay, func() {
|
||||
if err := supportsOverlay(os.Args[1]); err != nil {
|
||||
panic(err)
|
||||
}
|
||||
})
|
||||
reexec.Register(reexecMknodChar0, func() {
|
||||
if err := mknodChar0Overlay(os.Args[1]); err != nil {
|
||||
panic(err)
|
||||
}
|
||||
})
|
||||
reexec.Register(reexecSetOpaque, func() {
|
||||
if err := replaceDirWithOverlayOpaque(os.Args[1]); err != nil {
|
||||
panic(err)
|
||||
}
|
||||
})
|
||||
if reexec.Init() {
|
||||
os.Exit(0)
|
||||
}
|
||||
}
|
||||
|
|
|
|||
|
|
@ -2,6 +2,6 @@
|
|||
|
||||
package archive // import "github.com/docker/docker/pkg/archive"
|
||||
|
||||
func getWhiteoutConverter(format WhiteoutFormat, inUserNS bool) tarWhiteoutConverter {
|
||||
return nil
|
||||
func getWhiteoutConverter(format WhiteoutFormat, inUserNS bool) (tarWhiteoutConverter, error) {
|
||||
return nil, nil
|
||||
}
|
||||
|
|
|
|||
Loading…
Reference in New Issue