package fusefrontend_reverse import ( "log" "os" "path/filepath" "sync" "syscall" "time" "github.com/hanwen/go-fuse/fuse" "github.com/hanwen/go-fuse/fuse/nodefs" "github.com/rfjakob/gocryptfs/internal/nametransform" "github.com/rfjakob/gocryptfs/internal/tlog" ) const ( shortNameMax = 176 ) var longnameParentCache map[string]string var longnameCacheLock sync.Mutex // Very simple cache cleaner: Nuke it every hour func longnameCacheCleaner() { for { time.Sleep(time.Hour) longnameCacheLock.Lock() longnameParentCache = map[string]string{} longnameCacheLock.Unlock() } } func initLongnameCache() { if longnameParentCache != nil { return } longnameParentCache = map[string]string{} go longnameCacheCleaner() } // findLongnameParent converts "gocryptfs.longname.XYZ" to the plaintext name func (rfs *ReverseFS) findLongnameParent(dir string, dirIV []byte, longname string) (plaintextName string, err error) { longnameCacheLock.Lock() hit := longnameParentCache[longname] longnameCacheLock.Unlock() if hit != "" { return hit, nil } absDir := filepath.Join(rfs.args.Cipherdir, dir) dirfd, err := os.Open(absDir) if err != nil { tlog.Warn.Printf("findLongnameParent: opendir failed: %v\n", err) return "", err } dirEntries, err := dirfd.Readdirnames(-1) if err != nil { return "", err } longnameCacheLock.Lock() defer longnameCacheLock.Unlock() for _, plaintextName = range dirEntries { if len(plaintextName) <= shortNameMax { continue } cName := rfs.nameTransform.EncryptName(plaintextName, dirIV) if len(cName) <= syscall.NAME_MAX { log.Panic("logic error or wrong shortNameMax constant?") } hName := rfs.nameTransform.HashLongName(cName) longnameParentCache[hName] = plaintextName if longname == hName { hit = plaintextName } } if hit == "" { return "", syscall.ENOENT } return hit, nil } func (rfs *ReverseFS) newNameFile(relPath string) (nodefs.File, fuse.Status) { dotName := filepath.Base(relPath) // gocryptfs.longname.XYZ.name longname := dotName[:len(dotName)-len(nametransform.LongNameSuffix)] // gocryptfs.longname.XYZ // cipher directory cDir := saneDir(relPath) // plain directory pDir, err := rfs.decryptPath(cDir) if err != nil { return nil, fuse.ToStatus(err) } dirIV := derivePathIV(cDir, ivPurposeDirIV) // plain name pName, err := rfs.findLongnameParent(pDir, dirIV, longname) if err != nil { return nil, fuse.ToStatus(err) } content := []byte(rfs.nameTransform.EncryptName(pName, dirIV)) parentFile := filepath.Join(rfs.args.Cipherdir, pDir, pName) return rfs.newVirtualFile(content, parentFile) }