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package pathfs_frontend
import (
"syscall"
"io/ioutil"
"os"
"path/filepath"
"time"
"github.com/hanwen/go-fuse/fuse"
"github.com/hanwen/go-fuse/fuse/nodefs"
"github.com/hanwen/go-fuse/fuse/pathfs"
"github.com/rfjakob/gocryptfs/cryptfs"
)
type FS struct {
*cryptfs.CryptFS
pathfs.FileSystem // loopbackFileSystem, see go-fuse/fuse/pathfs/loopback.go
backing string // Backing directory
}
// Encrypted FUSE overlay filesystem
func NewFS(key []byte, backing string, useOpenssl bool, plaintextNames bool) *FS {
return &FS{
CryptFS: cryptfs.NewCryptFS(key, useOpenssl, plaintextNames),
FileSystem: pathfs.NewLoopbackFileSystem(backing),
backing: backing,
}
}
// GetPath - get the absolute encrypted path of the backing file
// from the relative plaintext path "relPath"
func (fs *FS) GetPath(relPath string) string {
return filepath.Join(fs.backing, fs.EncryptPath(relPath))
}
func (fs *FS) GetAttr(name string, context *fuse.Context) (*fuse.Attr, fuse.Status) {
cryptfs.Debug.Printf("FS.GetAttr('%s')\n", name)
if fs.CryptFS.IsFiltered(name) {
return nil, fuse.EPERM
}
cName := fs.EncryptPath(name)
a, status := fs.FileSystem.GetAttr(cName, context)
if a == nil {
cryptfs.Debug.Printf("FS.GetAttr failed: %s\n", status.String())
return a, status
}
if a.IsRegular() {
a.Size = fs.CipherSizeToPlainSize(a.Size)
} else if a.IsSymlink() {
target, _ := fs.Readlink(name, context)
a.Size = uint64(len(target))
}
return a, status
}
func (fs *FS) OpenDir(dirName string, context *fuse.Context) ([]fuse.DirEntry, fuse.Status) {
cryptfs.Debug.Printf("OpenDir(%s)\n", dirName)
cipherEntries, status := fs.FileSystem.OpenDir(fs.EncryptPath(dirName), context)
var plain []fuse.DirEntry
if cipherEntries != nil {
for i := range cipherEntries {
cName := cipherEntries[i].Name
if dirName == "" && cName == cryptfs.ConfDefaultName {
// silently ignore "gocryptfs.conf" in the top level dir
continue
}
if cName == cryptfs.DIRIV_FILENAME {
// silently ignore "gocryptfs.diriv" everywhere
continue
}
name, err := fs.DecryptPath(cName)
if err != nil {
cryptfs.Warn.Printf("Invalid name \"%s\" in dir \"%s\": %s\n", cName, dirName, err)
continue
}
cipherEntries[i].Name = name
plain = append(plain, cipherEntries[i])
}
}
return plain, status
}
// We always need read access to do read-modify-write cycles
func (fs *FS) mangleOpenFlags(flags uint32) (newFlags int, writeOnly bool) {
newFlags = int(flags)
if newFlags&os.O_WRONLY > 0 {
writeOnly = true
newFlags = newFlags ^ os.O_WRONLY | os.O_RDWR
}
// We also cannot open the file in append mode, we need to seek back for RMW
newFlags = newFlags &^ os.O_APPEND
return newFlags, writeOnly
}
func (fs *FS) Open(path string, flags uint32, context *fuse.Context) (fuseFile nodefs.File, status fuse.Status) {
cryptfs.Debug.Printf("Open(%s)\n", path)
if fs.CryptFS.IsFiltered(path) {
return nil, fuse.EPERM
}
iflags, writeOnly := fs.mangleOpenFlags(flags)
f, err := os.OpenFile(fs.GetPath(path), iflags, 0666)
if err != nil {
return nil, fuse.ToStatus(err)
}
return NewFile(f, writeOnly, fs.CryptFS), fuse.OK
}
func (fs *FS) Create(path string, flags uint32, mode uint32, context *fuse.Context) (fuseFile nodefs.File, code fuse.Status) {
if fs.CryptFS.IsFiltered(path) {
return nil, fuse.EPERM
}
iflags, writeOnly := fs.mangleOpenFlags(flags)
f, err := os.OpenFile(fs.GetPath(path), iflags|os.O_CREATE, os.FileMode(mode))
if err != nil {
return nil, fuse.ToStatus(err)
}
return NewFile(f, writeOnly, fs.CryptFS), fuse.OK
}
func (fs *FS) Chmod(path string, mode uint32, context *fuse.Context) (code fuse.Status) {
if fs.CryptFS.IsFiltered(path) {
return fuse.EPERM
}
return fs.FileSystem.Chmod(fs.EncryptPath(path), mode, context)
}
func (fs *FS) Chown(path string, uid uint32, gid uint32, context *fuse.Context) (code fuse.Status) {
if fs.CryptFS.IsFiltered(path) {
return fuse.EPERM
}
return fs.FileSystem.Chown(fs.EncryptPath(path), uid, gid, context)
}
func (fs *FS) Mknod(name string, mode uint32, dev uint32, context *fuse.Context) (code fuse.Status) {
if fs.CryptFS.IsFiltered(name) {
return fuse.EPERM
}
return fs.FileSystem.Mknod(fs.EncryptPath(name), mode, dev, context)
}
func (fs *FS) Truncate(path string, offset uint64, context *fuse.Context) (code fuse.Status) {
cryptfs.Warn.Printf("Truncate of a closed file is not supported, returning ENOSYS\n")
return fuse.ENOSYS
}
func (fs *FS) Utimens(path string, Atime *time.Time, Mtime *time.Time, context *fuse.Context) (code fuse.Status) {
if fs.CryptFS.IsFiltered(path) {
return fuse.EPERM
}
return fs.FileSystem.Utimens(fs.EncryptPath(path), Atime, Mtime, context)
}
func (fs *FS) Readlink(name string, context *fuse.Context) (out string, status fuse.Status) {
dst, status := fs.FileSystem.Readlink(fs.EncryptPath(name), context)
if status != fuse.OK {
return "", status
}
dstPlain, err := fs.DecryptPath(dst)
if err != nil {
cryptfs.Warn.Printf("Failed decrypting symlink: %s\n", err.Error())
return "", fuse.EIO
}
return dstPlain, status
}
func (fs *FS) Mkdir(relPath string, mode uint32, context *fuse.Context) (code fuse.Status) {
if fs.CryptFS.IsFiltered(relPath) {
return fuse.EPERM
}
encPath := fs.GetPath(relPath)
diriv := cryptfs.RandBytes(cryptfs.DIRIV_LEN)
dirivPath := filepath.Join(encPath, cryptfs.DIRIV_FILENAME)
// Create directory
err := os.Mkdir(encPath, os.FileMode(mode))
if err != nil {
return fuse.ToStatus(err)
}
// Create gocryptfs.diriv inside
// 0444 permissions: the file is not secret but should not be written to
err = ioutil.WriteFile(dirivPath, diriv, 0444)
if err != nil {
cryptfs.Warn.Printf("Creating %s in dir %s failed: %v\n", cryptfs.DIRIV_FILENAME, encPath, err)
err2 := syscall.Rmdir(encPath)
if err2 != nil {
cryptfs.Warn.Printf("Removing broken directory failed: %v\n", err2)
}
return fuse.ToStatus(err)
}
return fuse.OK
}
func (fs *FS) Unlink(name string, context *fuse.Context) (code fuse.Status) {
if fs.CryptFS.IsFiltered(name) {
return fuse.EPERM
}
cName := fs.EncryptPath(name)
code = fs.FileSystem.Unlink(cName, context)
if code != fuse.OK {
cryptfs.Warn.Printf("Unlink failed on %s [%s], code=%s\n", name, cName, code.String())
}
return code
}
func (fs *FS) Rmdir(name string, context *fuse.Context) (code fuse.Status) {
return fs.FileSystem.Rmdir(fs.EncryptPath(name), context)
}
func (fs *FS) Symlink(pointedTo string, linkName string, context *fuse.Context) (code fuse.Status) {
if fs.CryptFS.IsFiltered(linkName) {
return fuse.EPERM
}
// TODO symlink encryption
cryptfs.Debug.Printf("Symlink(\"%s\", \"%s\")\n", pointedTo, linkName)
return fs.FileSystem.Symlink(fs.EncryptPath(pointedTo), fs.EncryptPath(linkName), context)
}
func (fs *FS) Rename(oldPath string, newPath string, context *fuse.Context) (code fuse.Status) {
if fs.CryptFS.IsFiltered(newPath) {
return fuse.EPERM
}
return fs.FileSystem.Rename(fs.EncryptPath(oldPath), fs.EncryptPath(newPath), context)
}
func (fs *FS) Link(orig string, newName string, context *fuse.Context) (code fuse.Status) {
if fs.CryptFS.IsFiltered(newName) {
return fuse.EPERM
}
return fs.FileSystem.Link(fs.EncryptPath(orig), fs.EncryptPath(newName), context)
}
func (fs *FS) Access(name string, mode uint32, context *fuse.Context) (code fuse.Status) {
if fs.CryptFS.IsFiltered(name) {
return fuse.EPERM
}
return fs.FileSystem.Access(fs.EncryptPath(name), mode, context)
}
func (fs *FS) GetXAttr(name string, attr string, context *fuse.Context) ([]byte, fuse.Status) {
return nil, fuse.ENOSYS
}
func (fs *FS) SetXAttr(name string, attr string, data []byte, flags int, context *fuse.Context) fuse.Status {
return fuse.ENOSYS
}
func (fs *FS) ListXAttr(name string, context *fuse.Context) ([]string, fuse.Status) {
return nil, fuse.ENOSYS
}
func (fs *FS) RemoveXAttr(name string, attr string, context *fuse.Context) fuse.Status {
return fuse.ENOSYS
}
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