// WriteLongName encrypts plainName and writes it into "hashName.name".
// For the convenience of the caller, plainName may also be a path and will be
// converted internally.
func (n *NameTransform) WriteLongName(dirfd *os.File, hashName string, plainName string) (err error) {
plainName = filepath.Base(plainName)
// Encrypt the basename
dirIV, err := ReadDirIVAt(dirfd)
if err != nil {
return err
}
cName := n.EncryptName(plainName, dirIV)
// Write the encrypted name into hashName.name
fdRaw, err := syscallcompat.Openat(int(dirfd.Fd()), hashName+LongNameSuffix,
syscall.O_WRONLY|syscall.O_CREAT|syscall.O_EXCL, 0600)
if err != nil {
tlog.Warn.Printf("WriteLongName: Openat: %v", err)
return err
}
fd := os.NewFile(uintptr(fdRaw), hashName+LongNameSuffix)
defer fd.Close()
_, err = fd.Write([]byte(cName))
if err != nil {
tlog.Warn.Printf("WriteLongName: Write: %v", err)
}
return err
}
// ReadDirIVAt reads "gocryptfs.diriv" from the directory that is opened as "dirfd".
// Using the dirfd makes it immune to concurrent renames of the directory.
func ReadDirIVAt(dirfd *os.File) (iv []byte, err error) {
fdRaw, err := syscallcompat.Openat(int(dirfd.Fd()), DirIVFilename, syscall.O_RDONLY, 0)
if err != nil {
tlog.Warn.Printf("ReadDirIVAt: opening %q in dir %q failed: %v",
DirIVFilename, dirfd.Name(), err)
return nil, err
}
fd := os.NewFile(uintptr(fdRaw), DirIVFilename)
defer fd.Close()
return fdReadDirIV(fd)
}
// Create implements pathfs.Filesystem.
func (fs *FS) Create(path string, flags uint32, mode uint32, context *fuse.Context) (fuseFile nodefs.File, code fuse.Status) {
if fs.isFiltered(path) {
return nil, fuse.EPERM
}
iflags, writeOnly := fs.mangleOpenFlags(flags)
cPath, err := fs.getBackingPath(path)
if err != nil {
return nil, fuse.ToStatus(err)
}
var fd *os.File
cName := filepath.Base(cPath)
// Handle long file name
if nametransform.IsLongContent(cName) {
var dirfd *os.File
dirfd, err = os.Open(filepath.Dir(cPath))
if err != nil {
return nil, fuse.ToStatus(err)
}
defer dirfd.Close()
// Create ".name"
err = fs.nameTransform.WriteLongName(dirfd, cName, path)
if err != nil {
return nil, fuse.ToStatus(err)
}
// Create content
var fdRaw int
fdRaw, err = syscallcompat.Openat(int(dirfd.Fd()), cName, iflags|os.O_CREATE, mode)
if err != nil {
nametransform.DeleteLongName(dirfd, cName)
return nil, fuse.ToStatus(err)
}
fd = os.NewFile(uintptr(fdRaw), cName)
} else {
// Normal (short) file name
fd, err = os.OpenFile(cPath, iflags|os.O_CREATE, os.FileMode(mode))
if err != nil {
return nil, fuse.ToStatus(err)
}
}
// Set owner
if fs.args.PreserveOwner {
err = fd.Chown(int(context.Owner.Uid), int(context.Owner.Gid))
if err != nil {
tlog.Warn.Printf("Create: fd.Chown failed: %v", err)
}
}
return NewFile(fd, writeOnly, fs)
}
// Rmdir implements pathfs.FileSystem
func (fs *FS) Rmdir(path string, context *fuse.Context) (code fuse.Status) {
cPath, err := fs.getBackingPath(path)
if err != nil {
return fuse.ToStatus(err)
}
if fs.args.PlaintextNames {
err = syscall.Rmdir(cPath)
return fuse.ToStatus(err)
}
parentDir := filepath.Dir(cPath)
parentDirFd, err := os.Open(parentDir)
if err != nil {
return fuse.ToStatus(err)
}
defer parentDirFd.Close()
cName := filepath.Base(cPath)
dirfdRaw, err := syscallcompat.Openat(int(parentDirFd.Fd()), cName,
syscall.O_RDONLY, 0)
if err == syscall.EACCES {
// We need permission to read and modify the directory
tlog.Debug.Printf("Rmdir: handling EACCESS")
// TODO use syscall.Fstatat once it is available in Go
var fi os.FileInfo
fi, err = os.Lstat(cPath)
if err != nil {
tlog.Debug.Printf("Rmdir: Stat: %v", err)
return fuse.ToStatus(err)
}
origMode := fi.Mode()
// TODO use syscall.Chmodat once it is available in Go
err = os.Chmod(cPath, origMode|0700)
if err != nil {
tlog.Debug.Printf("Rmdir: Chmod failed: %v", err)
return fuse.ToStatus(err)
}
// Retry open
var st syscall.Stat_t
syscall.Lstat(cPath, &st)
dirfdRaw, err = syscallcompat.Openat(int(parentDirFd.Fd()), cName,
syscall.O_RDONLY, 0)
// Undo the chmod if removing the directory failed
defer func() {
if code != fuse.OK {
err = os.Chmod(cPath, origMode)
if err != nil {
tlog.Warn.Printf("Rmdir: Chmod rollback failed: %v", err)
}
}
}()
}
if err != nil {
tlog.Debug.Printf("Rmdir: Open: %v", err)
return fuse.ToStatus(err)
}
dirfd := os.NewFile(uintptr(dirfdRaw), cName)
defer dirfd.Close()
children, err := dirfd.Readdirnames(10)
if err == nil {
// If the directory is not empty besides gocryptfs.diriv, do not even
// attempt the dance around gocryptfs.diriv.
if len(children) > 1 {
return fuse.ToStatus(syscall.ENOTEMPTY)
}
// Move "gocryptfs.diriv" to the parent dir as "gocryptfs.diriv.rmdir.XYZ"
tmpName := fmt.Sprintf("gocryptfs.diriv.rmdir.%d", cryptocore.RandUint64())
tlog.Debug.Printf("Rmdir: Renaming %s to %s", nametransform.DirIVFilename, tmpName)
// The directory is in an inconsistent state between rename and rmdir.
// Protect against concurrent readers.
fs.dirIVLock.Lock()
defer fs.dirIVLock.Unlock()
err = syscallcompat.Renameat(int(dirfd.Fd()), nametransform.DirIVFilename,
int(parentDirFd.Fd()), tmpName)
if err != nil {
tlog.Warn.Printf("Rmdir: Renaming %s to %s failed: %v",
nametransform.DirIVFilename, tmpName, err)
return fuse.ToStatus(err)
}
// Actual Rmdir
// TODO Use syscall.Unlinkat with the AT_REMOVEDIR flag once it is available
// in Go
err = syscall.Rmdir(cPath)
if err != nil {
// This can happen if another file in the directory was created in the
// meantime, undo the rename
err2 := syscallcompat.Renameat(int(parentDirFd.Fd()), tmpName,
int(dirfd.Fd()), nametransform.DirIVFilename)
if err != nil {
tlog.Warn.Printf("Rmdir: Rename rollback failed: %v", err2)
}
return fuse.ToStatus(err)
}
// Delete "gocryptfs.diriv.rmdir.XYZ"
err = syscallcompat.Unlinkat(int(parentDirFd.Fd()), tmpName)
if err != nil {
tlog.Warn.Printf("Rmdir: Could not clean up %s: %v", tmpName, err)
}
} else if err == io.EOF {
// The directory is empty
tlog.Warn.Printf("Rmdir: %q: gocryptfs.diriv is missing", cPath)
err = syscall.Rmdir(cPath)
if err != nil {
return fuse.ToStatus(err)
}
} else {
tlog.Warn.Printf("Rmdir: Readdirnames: %v", err)
return fuse.ToStatus(err)
}
// Delete .name file
if nametransform.IsLongContent(cName) {
nametransform.DeleteLongName(parentDirFd, cName)
}
// The now-deleted directory may have been in the DirIV cache. Clear it.
fs.nameTransform.DirIVCache.Clear()
return fuse.OK
}
