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-rw-r--r--pkg/sentry/fs/dirent.go3
-rw-r--r--pkg/sentry/fs/fsutil/inode.go4
-rw-r--r--pkg/sentry/fs/gofer/path.go9
-rw-r--r--pkg/sentry/fs/host/inode.go2
-rw-r--r--pkg/sentry/fs/inode.go9
-rw-r--r--pkg/sentry/fs/inode_operations.go13
-rw-r--r--pkg/sentry/fs/inode_overlay.go101
-rw-r--r--pkg/sentry/fs/mock.go2
-rw-r--r--pkg/sentry/fs/ramfs/dir.go24
-rw-r--r--pkg/sentry/fs/tmpfs/inode_file.go4
-rw-r--r--pkg/sentry/fs/tmpfs/tmpfs.go20
11 files changed, 120 insertions, 71 deletions
diff --git a/pkg/sentry/fs/dirent.go b/pkg/sentry/fs/dirent.go
index d6a19dc81..15a0129ce 100644
--- a/pkg/sentry/fs/dirent.go
+++ b/pkg/sentry/fs/dirent.go
@@ -1563,6 +1563,7 @@ func Rename(ctx context.Context, root *Dirent, oldParent *Dirent, oldName string
}
// newName doesn't exist; simply create it below.
+ replaced = nil
} else {
// Check constraints on the dirent being replaced.
@@ -1620,7 +1621,7 @@ func Rename(ctx context.Context, root *Dirent, oldParent *Dirent, oldName string
replaced.DecRef()
}
- if err := renamed.Inode.Rename(ctx, oldParent, renamed, newParent, newName); err != nil {
+ if err := renamed.Inode.Rename(ctx, oldParent, renamed, newParent, newName, replaced != nil); err != nil {
return err
}
diff --git a/pkg/sentry/fs/fsutil/inode.go b/pkg/sentry/fs/fsutil/inode.go
index bd3bd1bb2..c1ad45e52 100644
--- a/pkg/sentry/fs/fsutil/inode.go
+++ b/pkg/sentry/fs/fsutil/inode.go
@@ -338,7 +338,7 @@ func (InodeNotDirectory) RemoveDirectory(context.Context, *fs.Inode, string) err
}
// Rename implements fs.FileOperations.Rename.
-func (InodeNotDirectory) Rename(context.Context, *fs.Inode, string, *fs.Inode, string) error {
+func (InodeNotDirectory) Rename(context.Context, *fs.Inode, string, *fs.Inode, string, bool) error {
return syserror.EINVAL
}
@@ -378,7 +378,7 @@ func (InodeNoopTruncate) Truncate(context.Context, *fs.Inode, int64) error {
type InodeNotRenameable struct{}
// Rename implements fs.InodeOperations.Rename.
-func (InodeNotRenameable) Rename(context.Context, *fs.Inode, string, *fs.Inode, string) error {
+func (InodeNotRenameable) Rename(context.Context, *fs.Inode, string, *fs.Inode, string, bool) error {
return syserror.EINVAL
}
diff --git a/pkg/sentry/fs/gofer/path.go b/pkg/sentry/fs/gofer/path.go
index 43f990d16..2ba400836 100644
--- a/pkg/sentry/fs/gofer/path.go
+++ b/pkg/sentry/fs/gofer/path.go
@@ -298,7 +298,7 @@ func (i *inodeOperations) RemoveDirectory(ctx context.Context, dir *fs.Inode, na
}
// Rename renames this node.
-func (i *inodeOperations) Rename(ctx context.Context, oldParent *fs.Inode, oldName string, newParent *fs.Inode, newName string) error {
+func (i *inodeOperations) Rename(ctx context.Context, oldParent *fs.Inode, oldName string, newParent *fs.Inode, newName string, replacement bool) error {
// Unwrap the new parent to a *inodeOperations.
newParentInodeOperations, ok := newParent.InodeOperations.(*inodeOperations)
if !ok {
@@ -323,7 +323,12 @@ func (i *inodeOperations) Rename(ctx context.Context, oldParent *fs.Inode, oldNa
oldParentInodeOperations.cachingInodeOps.DecLinks(ctx)
}
if i.session().cachePolicy.cacheUAttrs(newParent) {
- newParentInodeOperations.cachingInodeOps.IncLinks(ctx)
+ // Only IncLinks if there is a new addition to
+ // newParent. If this is replacement, then the total
+ // count remains the same.
+ if !replacement {
+ newParentInodeOperations.cachingInodeOps.IncLinks(ctx)
+ }
}
}
if i.session().cachePolicy.cacheReaddir() {
diff --git a/pkg/sentry/fs/host/inode.go b/pkg/sentry/fs/host/inode.go
index 6ff6c3254..2030edcb4 100644
--- a/pkg/sentry/fs/host/inode.go
+++ b/pkg/sentry/fs/host/inode.go
@@ -296,7 +296,7 @@ func (i *inodeOperations) RemoveDirectory(ctx context.Context, dir *fs.Inode, na
}
// Rename implements fs.InodeOperations.Rename.
-func (i *inodeOperations) Rename(ctx context.Context, oldParent *fs.Inode, oldName string, newParent *fs.Inode, newName string) error {
+func (i *inodeOperations) Rename(ctx context.Context, oldParent *fs.Inode, oldName string, newParent *fs.Inode, newName string, replacement bool) error {
op, ok := oldParent.InodeOperations.(*inodeOperations)
if !ok {
return syscall.EXDEV
diff --git a/pkg/sentry/fs/inode.go b/pkg/sentry/fs/inode.go
index 08b5c5902..b8b5c1528 100644
--- a/pkg/sentry/fs/inode.go
+++ b/pkg/sentry/fs/inode.go
@@ -152,7 +152,8 @@ func (i *Inode) WriteOut(ctx context.Context) error {
// Lookup calls i.InodeOperations.Lookup with i as the directory.
func (i *Inode) Lookup(ctx context.Context, name string) (*Dirent, error) {
if i.overlay != nil {
- return overlayLookup(ctx, i.overlay, i, name)
+ d, _, err := overlayLookup(ctx, i.overlay, i, name)
+ return d, err
}
return i.InodeOperations.Lookup(ctx, i, name)
}
@@ -211,11 +212,11 @@ func (i *Inode) Remove(ctx context.Context, d *Dirent, remove *Dirent) error {
}
// Rename calls i.InodeOperations.Rename with the given arguments.
-func (i *Inode) Rename(ctx context.Context, oldParent *Dirent, renamed *Dirent, newParent *Dirent, newName string) error {
+func (i *Inode) Rename(ctx context.Context, oldParent *Dirent, renamed *Dirent, newParent *Dirent, newName string, replacement bool) error {
if i.overlay != nil {
- return overlayRename(ctx, i.overlay, oldParent, renamed, newParent, newName)
+ return overlayRename(ctx, i.overlay, oldParent, renamed, newParent, newName, replacement)
}
- return i.InodeOperations.Rename(ctx, oldParent.Inode, renamed.name, newParent.Inode, newName)
+ return i.InodeOperations.Rename(ctx, oldParent.Inode, renamed.name, newParent.Inode, newName, replacement)
}
// Bind calls i.InodeOperations.Bind with i as the directory.
diff --git a/pkg/sentry/fs/inode_operations.go b/pkg/sentry/fs/inode_operations.go
index db40b5256..548f1eb8b 100644
--- a/pkg/sentry/fs/inode_operations.go
+++ b/pkg/sentry/fs/inode_operations.go
@@ -133,12 +133,15 @@ type InodeOperations interface {
// removed is empty.
RemoveDirectory(ctx context.Context, dir *Inode, name string) error
- // Rename atomically renames oldName under oldParent to newName
- // under newParent where oldParent and newParent are directories.
+ // Rename atomically renames oldName under oldParent to newName under
+ // newParent where oldParent and newParent are directories.
//
- // Implementations are responsible for rejecting renames that
- // replace non-empty directories.
- Rename(ctx context.Context, oldParent *Inode, oldName string, newParent *Inode, newName string) error
+ // If replacement is true, then newName already exists and this call
+ // will replace it with oldName.
+ //
+ // Implementations are responsible for rejecting renames that replace
+ // non-empty directories.
+ Rename(ctx context.Context, oldParent *Inode, oldName string, newParent *Inode, newName string, replacement bool) error
// Bind binds a new socket under dir at the given name.
// Implementations must ensure that name does not already exist.
diff --git a/pkg/sentry/fs/inode_overlay.go b/pkg/sentry/fs/inode_overlay.go
index 92a77917a..6e1dfecf9 100644
--- a/pkg/sentry/fs/inode_overlay.go
+++ b/pkg/sentry/fs/inode_overlay.go
@@ -44,7 +44,11 @@ func overlayWriteOut(ctx context.Context, o *overlayEntry) error {
return err
}
-func overlayLookup(ctx context.Context, parent *overlayEntry, inode *Inode, name string) (*Dirent, error) {
+// overlayLookup performs a lookup in parent.
+//
+// If name exists, it returns true if the Dirent is in the upper, false if the
+// Dirent is in the lower.
+func overlayLookup(ctx context.Context, parent *overlayEntry, inode *Inode, name string) (*Dirent, bool, error) {
// Hot path. Avoid defers.
parent.copyMu.RLock()
@@ -71,7 +75,7 @@ func overlayLookup(ctx context.Context, parent *overlayEntry, inode *Inode, name
// We encountered an error that an overlay cannot handle,
// we must propagate it to the caller.
parent.copyMu.RUnlock()
- return nil, err
+ return nil, false, err
}
if child != nil {
if child.IsNegative() {
@@ -93,23 +97,23 @@ func overlayLookup(ctx context.Context, parent *overlayEntry, inode *Inode, name
// that negative Dirent being cached in
// the Dirent tree, so we can return
// one from the overlay.
- return NewNegativeDirent(name), nil
+ return NewNegativeDirent(name), false, nil
}
// Upper fs is not OK with a negative Dirent
// being cached in the Dirent tree, so don't
// return one.
- return nil, syserror.ENOENT
+ return nil, false, syserror.ENOENT
}
entry, err := newOverlayEntry(ctx, upperInode, nil, false)
if err != nil {
// Don't leak resources.
upperInode.DecRef()
parent.copyMu.RUnlock()
- return nil, err
+ return nil, false, err
}
d, err := NewDirent(newOverlayInode(ctx, entry, inode.MountSource), name), nil
parent.copyMu.RUnlock()
- return d, err
+ return d, true, err
}
}
@@ -127,7 +131,7 @@ func overlayLookup(ctx context.Context, parent *overlayEntry, inode *Inode, name
upperInode.DecRef()
}
parent.copyMu.RUnlock()
- return nil, err
+ return nil, false, err
}
if child != nil {
if !child.IsNegative() {
@@ -158,9 +162,9 @@ func overlayLookup(ctx context.Context, parent *overlayEntry, inode *Inode, name
// one as well. See comments above regarding negativeUpperChild
// for more info.
if negativeUpperChild {
- return NewNegativeDirent(name), nil
+ return NewNegativeDirent(name), false, nil
}
- return nil, syserror.ENOENT
+ return nil, false, syserror.ENOENT
}
// Did we find a lower Inode? Remember this because we may decide we don't
@@ -195,11 +199,11 @@ func overlayLookup(ctx context.Context, parent *overlayEntry, inode *Inode, name
lowerInode.DecRef()
}
parent.copyMu.RUnlock()
- return nil, err
+ return nil, false, err
}
d, err := NewDirent(newOverlayInode(ctx, entry, inode.MountSource), name), nil
parent.copyMu.RUnlock()
- return d, err
+ return d, upperInode != nil, err
}
func overlayCreate(ctx context.Context, o *overlayEntry, parent *Dirent, name string, flags FileFlags, perm FilePermissions) (*File, error) {
@@ -317,7 +321,7 @@ func overlayRemove(ctx context.Context, o *overlayEntry, parent *Dirent, child *
return nil
}
-func overlayRename(ctx context.Context, o *overlayEntry, oldParent *Dirent, renamed *Dirent, newParent *Dirent, newName string) error {
+func overlayRename(ctx context.Context, o *overlayEntry, oldParent *Dirent, renamed *Dirent, newParent *Dirent, newName string, replacement bool) error {
// To be able to copy these up below, they have to be part of an
// overlay file system.
//
@@ -327,36 +331,57 @@ func overlayRename(ctx context.Context, o *overlayEntry, oldParent *Dirent, rena
return syserror.EXDEV
}
- // Check here if the file to be replaced exists and is a non-empty
- // directory. If we copy up first, we may end up copying the directory
- // but none of its children, so the directory will appear empty in the
- // upper fs, which will then allow the rename to proceed when it should
- // return ENOTEMPTY.
- replaced, err := newParent.Inode.Lookup(ctx, newName)
- if err != nil && err != syserror.ENOENT {
- return err
- }
- if err == nil {
- // NOTE: We must drop the reference on replaced before we make
- // the rename call. For that reason we can't use defer.
- if !replaced.IsNegative() && IsDir(replaced.Inode.StableAttr) {
- children, err := readdirOne(ctx, replaced)
- if err != nil {
- replaced.DecRef()
- return err
+ if replacement {
+ // Check here if the file to be replaced exists and is a
+ // non-empty directory. If we copy up first, we may end up
+ // copying the directory but none of its children, so the
+ // directory will appear empty in the upper fs, which will then
+ // allow the rename to proceed when it should return ENOTEMPTY.
+ //
+ // NOTE: Ideally, we'd just pass in the replaced
+ // Dirent from Rename, but we must drop the reference on
+ // replaced before we make the rename call, so Rename can't
+ // pass the Dirent to the Inode without significantly
+ // complicating the API. Thus we look it up again here.
+ //
+ // For the same reason we can't use defer here.
+ replaced, inUpper, err := overlayLookup(ctx, newParent.Inode.overlay, newParent.Inode, newName)
+ // If err == ENOENT or a negative Dirent is returned, then
+ // newName has been removed out from under us. That's fine;
+ // filesystems where that can happen must handle stale
+ // 'replaced'.
+ if err != nil && err != syserror.ENOENT {
+ return err
+ }
+ if err == nil {
+ if !inUpper {
+ // newName doesn't exist in
+ // newParent.Inode.overlay.upper, thus from
+ // that Inode's perspective this won't be a
+ // replacing rename.
+ replacement = false
}
- // readdirOne ensures that "." and ".." are not
- // included among the returned children, so we don't
- // need to bother checking for them.
- if len(children) > 0 {
- replaced.DecRef()
- return syserror.ENOTEMPTY
+ if !replaced.IsNegative() && IsDir(replaced.Inode.StableAttr) {
+ children, err := readdirOne(ctx, replaced)
+ if err != nil {
+ replaced.DecRef()
+ return err
+ }
+
+ // readdirOne ensures that "." and ".." are not
+ // included among the returned children, so we don't
+ // need to bother checking for them.
+ if len(children) > 0 {
+ replaced.DecRef()
+ return syserror.ENOTEMPTY
+ }
}
- }
- replaced.DecRef()
+ replaced.DecRef()
+ }
}
+
if err := copyUpLockedForRename(ctx, renamed); err != nil {
return err
}
@@ -364,7 +389,7 @@ func overlayRename(ctx context.Context, o *overlayEntry, oldParent *Dirent, rena
return err
}
oldName := renamed.name
- if err := o.upper.InodeOperations.Rename(ctx, oldParent.Inode.overlay.upper, oldName, newParent.Inode.overlay.upper, newName); err != nil {
+ if err := o.upper.InodeOperations.Rename(ctx, oldParent.Inode.overlay.upper, oldName, newParent.Inode.overlay.upper, newName, replacement); err != nil {
return err
}
if renamed.Inode.overlay.lowerExists {
diff --git a/pkg/sentry/fs/mock.go b/pkg/sentry/fs/mock.go
index abfdc6a25..118e30f63 100644
--- a/pkg/sentry/fs/mock.go
+++ b/pkg/sentry/fs/mock.go
@@ -132,7 +132,7 @@ func (n *MockInodeOperations) CreateDirectory(context.Context, *Inode, string, F
}
// Rename implements fs.InodeOperations.Rename.
-func (n *MockInodeOperations) Rename(ctx context.Context, oldParent *Inode, oldName string, newParent *Inode, newName string) error {
+func (n *MockInodeOperations) Rename(ctx context.Context, oldParent *Inode, oldName string, newParent *Inode, newName string, replacement bool) error {
n.renameCalled = true
return nil
}
diff --git a/pkg/sentry/fs/ramfs/dir.go b/pkg/sentry/fs/ramfs/dir.go
index 4da876ebd..b60dab243 100644
--- a/pkg/sentry/fs/ramfs/dir.go
+++ b/pkg/sentry/fs/ramfs/dir.go
@@ -15,6 +15,7 @@
package ramfs
import (
+ "fmt"
"sync"
"syscall"
@@ -383,8 +384,8 @@ func (d *Dir) GetFile(ctx context.Context, dirent *fs.Dirent, flags fs.FileFlags
}
// Rename implements fs.InodeOperations.Rename.
-func (*Dir) Rename(ctx context.Context, oldParent *fs.Inode, oldName string, newParent *fs.Inode, newName string) error {
- return Rename(ctx, oldParent.InodeOperations, oldName, newParent.InodeOperations, newName)
+func (*Dir) Rename(ctx context.Context, oldParent *fs.Inode, oldName string, newParent *fs.Inode, newName string, replacement bool) error {
+ return Rename(ctx, oldParent.InodeOperations, oldName, newParent.InodeOperations, newName, replacement)
}
// dirFileOperations implements fs.FileOperations for a ramfs directory.
@@ -456,7 +457,7 @@ func hasChildren(ctx context.Context, inode *fs.Inode) (bool, error) {
}
// Rename renames from a *ramfs.Dir to another *ramfs.Dir.
-func Rename(ctx context.Context, oldParent fs.InodeOperations, oldName string, newParent fs.InodeOperations, newName string) error {
+func Rename(ctx context.Context, oldParent fs.InodeOperations, oldName string, newParent fs.InodeOperations, newName string, replacement bool) error {
op, ok := oldParent.(*Dir)
if !ok {
return syserror.EXDEV
@@ -469,8 +470,14 @@ func Rename(ctx context.Context, oldParent fs.InodeOperations, oldName string, n
np.mu.Lock()
defer np.mu.Unlock()
- // Check whether the ramfs entry to be replaced is a non-empty directory.
- if replaced, ok := np.children[newName]; ok {
+ // Is this is an overwriting rename?
+ if replacement {
+ replaced, ok := np.children[newName]
+ if !ok {
+ panic(fmt.Sprintf("Dirent claims rename is replacement, but %q is missing from %+v", newName, np))
+ }
+
+ // Non-empty directories cannot be replaced.
if fs.IsDir(replaced.StableAttr) {
if ok, err := hasChildren(ctx, replaced); err != nil {
return err
@@ -478,6 +485,13 @@ func Rename(ctx context.Context, oldParent fs.InodeOperations, oldName string, n
return syserror.ENOTEMPTY
}
}
+
+ // Remove the replaced child and drop our reference on it.
+ inode, err := np.removeChildLocked(ctx, newName)
+ if err != nil {
+ return err
+ }
+ inode.DecRef()
}
// Be careful, we may have already grabbed this mutex above.
diff --git a/pkg/sentry/fs/tmpfs/inode_file.go b/pkg/sentry/fs/tmpfs/inode_file.go
index a98fbf0f1..3c84b2977 100644
--- a/pkg/sentry/fs/tmpfs/inode_file.go
+++ b/pkg/sentry/fs/tmpfs/inode_file.go
@@ -107,8 +107,8 @@ func (f *fileInodeOperations) Mappable(*fs.Inode) memmap.Mappable {
}
// Rename implements fs.InodeOperations.Rename.
-func (*fileInodeOperations) Rename(ctx context.Context, oldParent *fs.Inode, oldName string, newParent *fs.Inode, newName string) error {
- return rename(ctx, oldParent, oldName, newParent, newName)
+func (*fileInodeOperations) Rename(ctx context.Context, oldParent *fs.Inode, oldName string, newParent *fs.Inode, newName string, replacement bool) error {
+ return rename(ctx, oldParent, oldName, newParent, newName, replacement)
}
// GetFile implements fs.InodeOperations.GetFile.
diff --git a/pkg/sentry/fs/tmpfs/tmpfs.go b/pkg/sentry/fs/tmpfs/tmpfs.go
index 1a9d12c0b..a1672a4d0 100644
--- a/pkg/sentry/fs/tmpfs/tmpfs.go
+++ b/pkg/sentry/fs/tmpfs/tmpfs.go
@@ -38,7 +38,7 @@ var fsInfo = fs.Info{
}
// rename implements fs.InodeOperations.Rename for tmpfs nodes.
-func rename(ctx context.Context, oldParent *fs.Inode, oldName string, newParent *fs.Inode, newName string) error {
+func rename(ctx context.Context, oldParent *fs.Inode, oldName string, newParent *fs.Inode, newName string, replacement bool) error {
op, ok := oldParent.InodeOperations.(*Dir)
if !ok {
return syserror.EXDEV
@@ -47,7 +47,7 @@ func rename(ctx context.Context, oldParent *fs.Inode, oldName string, newParent
if !ok {
return syserror.EXDEV
}
- return ramfs.Rename(ctx, op.ramfsDir, oldName, np.ramfsDir, newName)
+ return ramfs.Rename(ctx, op.ramfsDir, oldName, np.ramfsDir, newName, replacement)
}
// Dir is a directory.
@@ -238,8 +238,8 @@ func (d *Dir) newCreateOps() *ramfs.CreateOps {
}
// Rename implements fs.InodeOperations.Rename.
-func (d *Dir) Rename(ctx context.Context, oldParent *fs.Inode, oldName string, newParent *fs.Inode, newName string) error {
- return rename(ctx, oldParent, oldName, newParent, newName)
+func (d *Dir) Rename(ctx context.Context, oldParent *fs.Inode, oldName string, newParent *fs.Inode, newName string, replacement bool) error {
+ return rename(ctx, oldParent, oldName, newParent, newName, replacement)
}
// StatFS implments fs.InodeOperations.StatFS.
@@ -266,8 +266,8 @@ func NewSymlink(ctx context.Context, target string, owner fs.FileOwner, msrc *fs
}
// Rename implements fs.InodeOperations.Rename.
-func (s *Symlink) Rename(ctx context.Context, oldParent *fs.Inode, oldName string, newParent *fs.Inode, newName string) error {
- return rename(ctx, oldParent, oldName, newParent, newName)
+func (s *Symlink) Rename(ctx context.Context, oldParent *fs.Inode, oldName string, newParent *fs.Inode, newName string, replacement bool) error {
+ return rename(ctx, oldParent, oldName, newParent, newName, replacement)
}
// StatFS returns the tmpfs info.
@@ -295,8 +295,8 @@ func NewSocket(ctx context.Context, socket transport.BoundEndpoint, owner fs.Fil
}
// Rename implements fs.InodeOperations.Rename.
-func (s *Socket) Rename(ctx context.Context, oldParent *fs.Inode, oldName string, newParent *fs.Inode, newName string) error {
- return rename(ctx, oldParent, oldName, newParent, newName)
+func (s *Socket) Rename(ctx context.Context, oldParent *fs.Inode, oldName string, newParent *fs.Inode, newName string, replacement bool) error {
+ return rename(ctx, oldParent, oldName, newParent, newName, replacement)
}
// StatFS returns the tmpfs info.
@@ -332,8 +332,8 @@ func NewFifo(ctx context.Context, owner fs.FileOwner, perms fs.FilePermissions,
}
// Rename implements fs.InodeOperations.Rename.
-func (f *Fifo) Rename(ctx context.Context, oldParent *fs.Inode, oldName string, newParent *fs.Inode, newName string) error {
- return rename(ctx, oldParent, oldName, newParent, newName)
+func (f *Fifo) Rename(ctx context.Context, oldParent *fs.Inode, oldName string, newParent *fs.Inode, newName string, replacement bool) error {
+ return rename(ctx, oldParent, oldName, newParent, newName, replacement)
}
// StatFS returns the tmpfs info.
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-29 03:30:37 +0000