summaryrefslogtreecommitdiffhomepage
path: root/pkg
diff options
context:
space:
mode:
authorNicolas Lacasse <nlacasse@google.com>2021-02-24 15:37:46 -0800
committergVisor bot <gvisor-bot@google.com>2021-02-24 15:39:32 -0800
commitf5692f7dcc48a76a5d7b45cdf71b59be876adb42 (patch)
treeb16a82bfc49ccc24b58397e3fabfee824eda92a8 /pkg
parent303c913c5e0e6f0bac766970d9ed19c08aabb980 (diff)
Kernfs should not try to rename a file to itself.
One precondition of VFS.PrepareRenameAt is that the `from` and `to` dentries are not the same. Kernfs was not checking this, which could lead to a deadlock. PiperOrigin-RevId: 359385974
Diffstat (limited to 'pkg')
-rw-r--r--pkg/sentry/fsimpl/kernfs/filesystem.go23
1 files changed, 14 insertions, 9 deletions
diff --git a/pkg/sentry/fsimpl/kernfs/filesystem.go b/pkg/sentry/fsimpl/kernfs/filesystem.go
index beb9302f6..badca4d9f 100644
--- a/pkg/sentry/fsimpl/kernfs/filesystem.go
+++ b/pkg/sentry/fsimpl/kernfs/filesystem.go
@@ -668,14 +668,14 @@ func (fs *Filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa
// Can we create the dst dentry?
var dst *Dentry
- pc := rp.Component()
- if pc == "." || pc == ".." {
+ newName := rp.Component()
+ if newName == "." || newName == ".." {
if noReplace {
return syserror.EEXIST
}
return syserror.EBUSY
}
- switch err := checkCreateLocked(ctx, rp.Credentials(), pc, dstDir); err {
+ switch err := checkCreateLocked(ctx, rp.Credentials(), newName, dstDir); err {
case nil:
// Ok, continue with rename as replacement.
case syserror.EEXIST:
@@ -683,13 +683,18 @@ func (fs *Filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa
// Won't overwrite existing node since RENAME_NOREPLACE was requested.
return syserror.EEXIST
}
- dst = dstDir.children[pc]
+ dst = dstDir.children[newName]
if dst == nil {
- panic(fmt.Sprintf("Child %q for parent Dentry %+v disappeared inside atomic section?", pc, dstDir))
+ panic(fmt.Sprintf("Child %q for parent Dentry %+v disappeared inside atomic section?", newName, dstDir))
}
default:
return err
}
+
+ if srcDir == dstDir && oldName == newName {
+ return nil
+ }
+
var dstVFSD *vfs.Dentry
if dst != nil {
dstVFSD = dst.VFSDentry()
@@ -712,7 +717,7 @@ func (fs *Filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa
if err := virtfs.PrepareRenameDentry(mntns, srcVFSD, dstVFSD); err != nil {
return err
}
- err = srcDir.inode.Rename(ctx, src.name, pc, src.inode, dstDir.inode)
+ err = srcDir.inode.Rename(ctx, src.name, newName, src.inode, dstDir.inode)
if err != nil {
virtfs.AbortRenameDentry(srcVFSD, dstVFSD)
return err
@@ -723,12 +728,12 @@ func (fs *Filesystem) RenameAt(ctx context.Context, rp *vfs.ResolvingPath, oldPa
dstDir.IncRef() // child (src) takes a ref on the new parent.
}
src.parent = dstDir
- src.name = pc
+ src.name = newName
if dstDir.children == nil {
dstDir.children = make(map[string]*Dentry)
}
- replaced := dstDir.children[pc]
- dstDir.children[pc] = src
+ replaced := dstDir.children[newName]
+ dstDir.children[newName] = src
var replaceVFSD *vfs.Dentry
if replaced != nil {
// deferDecRef so that fs.mu and dstDir.mu are unlocked by then.