Merge pull request #772 from nalind/overlay-perms

overlay: set permissions on "diff" correctly

drivers/overlay/overlay.go

@@ -593,20 +593,15 @@ func (d *Driver) create(id, parent string, opts *graphdriver.CreateOpts) (retErr
  if err := idtools.MkdirAllAs(path.Dir(dir), 0700, rootUID, rootGID); err != nil {
  return err
  }
- perms := defaultPerms
- if d.options.forceMask != nil {
- perms = *d.options.forceMask
- }
  if parent != "" {
  st, err := system.Stat(d.dir(parent))
  if err != nil {
  return err
  }
- perms = os.FileMode(st.Mode())
  rootUID = int(st.UID())
  rootGID = int(st.GID())
  }
- if err := idtools.MkdirAs(dir, perms, rootUID, rootGID); err != nil {
+ if err := idtools.MkdirAs(dir, 0700, rootUID, rootGID); err != nil {
  return err
  }
 
@@ -631,6 +626,18 @@ func (d *Driver) create(id, parent string, opts *graphdriver.CreateOpts) (retErr
  }
  }
 
+ perms := defaultPerms
+ if d.options.forceMask != nil {
+ perms = *d.options.forceMask
+ }
+ if parent != "" {
+ st, err := system.Stat(filepath.Join(d.dir(parent), "diff"))
+ if err != nil {
+ return err
+ }
+ perms = os.FileMode(st.Mode())
+ }
+
  if err := idtools.MkdirAs(path.Join(dir, "diff"), perms, rootUID, rootGID); err != nil {
  return err
  }
@@ -878,15 +885,21 @@ func (d *Driver) get(id string, disableShifting bool, options graphdriver.MountO
  if d.options.forceMask != nil {
  perms = *d.options.forceMask
  }
+ permsKnown := false
  st, err := os.Stat(filepath.Join(dir, nameWithSuffix("diff", diffN)))
  if err == nil {
  perms = os.FileMode(st.Mode())
+ permsKnown = true
  }
  for err == nil {
  absLowers = append(absLowers, filepath.Join(dir, nameWithSuffix("diff", diffN)))
  relLowers = append(relLowers, dumbJoin(string(link), "..", nameWithSuffix("diff", diffN)))
  diffN++
- _, err = os.Stat(filepath.Join(dir, nameWithSuffix("diff", diffN)))
+ st, err = os.Stat(filepath.Join(dir, nameWithSuffix("diff", diffN)))
+ if err == nil && !permsKnown {
+ perms = os.FileMode(st.Mode())
+ permsKnown = true
+ }
  }
 
  // For each lower, resolve its path, and append it and any additional diffN
@@ -897,10 +910,14 @@ func (d *Driver) get(id string, disableShifting bool, options graphdriver.MountO
  }
  lower := ""
  newpath := path.Join(d.home, l)
- if _, err := os.Stat(newpath); err != nil {
+ if st, err := os.Stat(newpath); err != nil {
  for _, p := range d.AdditionalImageStores() {
  lower = path.Join(p, d.name, l)
- if _, err2 := os.Stat(lower); err2 == nil {
+ if st2, err2 := os.Stat(lower); err2 == nil {
+ if !permsKnown {
+ perms = os.FileMode(st2.Mode())
+ permsKnown = true
+ }
  break
  }
  lower = ""
@@ -918,6 +935,10 @@ func (d *Driver) get(id string, disableShifting bool, options graphdriver.MountO
  return "", fmt.Errorf("Can't stat lower layer %q: %v", newpath, err)
  }
  } else {
+ if !permsKnown {
+ perms = os.FileMode(st.Mode())
+ permsKnown = true
+ }
  lower = newpath
  }
  absLowers = append(absLowers, lower)
@@ -1280,12 +1301,13 @@ func (d *Driver) UpdateLayerIDMap(id string, toContainer, toHost *idtools.IDMapp
  // Rotate the diff directories.
  i := 0
  perms := defaultPerms
+ st, err := os.Stat(nameWithSuffix(diffDir, i))
  if d.options.forceMask != nil {
  perms = *d.options.forceMask
- }
- st, err := os.Stat(nameWithSuffix(diffDir, i))
- if err == nil {
- perms = os.FileMode(st.Mode())
+ } else {
+  if err == nil {
+  perms = os.FileMode(st.Mode())
+ }
  }
  for err == nil {
  i++