rclone/crypt/crypt.go
2017-02-16 17:42:37 +00:00

603 lines
16 KiB
Go

// Package crypt provides wrappers for Fs and Object which implement encryption
package crypt
import (
"fmt"
"io"
"path"
"strings"
"sync"
"github.com/ncw/rclone/fs"
"github.com/pkg/errors"
)
// Globals
var (
// Flags
cryptShowMapping = fs.BoolP("crypt-show-mapping", "", false, "For all files listed show how the names encrypt.")
)
// Register with Fs
func init() {
fs.Register(&fs.RegInfo{
Name: "crypt",
Description: "Encrypt/Decrypt a remote",
NewFs: NewFs,
Options: []fs.Option{{
Name: "remote",
Help: "Remote to encrypt/decrypt.\nNormally should contain a ':' and a path, eg \"myremote:path/to/dir\",\n\"myremote:bucket\" or maybe \"myremote:\" (not recommended).",
}, {
Name: "filename_encryption",
Help: "How to encrypt the filenames.",
Examples: []fs.OptionExample{
{
Value: "off",
Help: "Don't encrypt the file names. Adds a \".bin\" extension only.",
}, {
Value: "standard",
Help: "Encrypt the filenames see the docs for the details.",
},
},
}, {
Name: "password",
Help: "Password or pass phrase for encryption.",
IsPassword: true,
}, {
Name: "password2",
Help: "Password or pass phrase for salt. Optional but recommended.\nShould be different to the previous password.",
IsPassword: true,
Optional: true,
}},
})
}
// NewFs contstructs an Fs from the path, container:path
func NewFs(name, rpath string) (fs.Fs, error) {
mode, err := NewNameEncryptionMode(fs.ConfigFileGet(name, "filename_encryption", "standard"))
if err != nil {
return nil, err
}
password := fs.ConfigFileGet(name, "password", "")
if password == "" {
return nil, errors.New("password not set in config file")
}
password, err = fs.Reveal(password)
if err != nil {
return nil, errors.Wrap(err, "failed to decrypt password")
}
salt := fs.ConfigFileGet(name, "password2", "")
if salt != "" {
salt, err = fs.Reveal(salt)
if err != nil {
return nil, errors.Wrap(err, "failed to decrypt password2")
}
}
cipher, err := newCipher(mode, password, salt)
if err != nil {
return nil, errors.Wrap(err, "failed to make cipher")
}
remote := fs.ConfigFileGet(name, "remote")
if strings.HasPrefix(remote, name+":") {
return nil, errors.New("can't point crypt remote at itself - check the value of the remote setting")
}
// Look for a file first
remotePath := path.Join(remote, cipher.EncryptFileName(rpath))
wrappedFs, err := fs.NewFs(remotePath)
// if that didn't produce a file, look for a directory
if err != fs.ErrorIsFile {
remotePath = path.Join(remote, cipher.EncryptDirName(rpath))
wrappedFs, err = fs.NewFs(remotePath)
}
if err != fs.ErrorIsFile && err != nil {
return nil, errors.Wrapf(err, "failed to make remote %q to wrap", remotePath)
}
f := &Fs{
Fs: wrappedFs,
name: name,
root: rpath,
cipher: cipher,
mode: mode,
}
// the features here are ones we could support, and they are
// ANDed with the ones from wrappedFs
f.features = (&fs.Features{
CaseInsensitive: mode == NameEncryptionOff,
DuplicateFiles: true,
ReadMimeType: false, // MimeTypes not supported with crypt
WriteMimeType: false,
}).Fill(f).Mask(wrappedFs)
return f, err
}
// Fs represents a wrapped fs.Fs
type Fs struct {
fs.Fs
name string
root string
features *fs.Features // optional features
cipher Cipher
mode NameEncryptionMode
}
// Name of the remote (as passed into NewFs)
func (f *Fs) Name() string {
return f.name
}
// Root of the remote (as passed into NewFs)
func (f *Fs) Root() string {
return f.root
}
// Features returns the optional features of this Fs
func (f *Fs) Features() *fs.Features {
return f.features
}
// String returns a description of the FS
func (f *Fs) String() string {
return fmt.Sprintf("Encrypted %s", f.Fs.String())
}
// List the Fs into a channel
func (f *Fs) List(opts fs.ListOpts, dir string) {
f.Fs.List(f.newListOpts(opts, dir), f.cipher.EncryptDirName(dir))
}
// NewObject finds the Object at remote.
func (f *Fs) NewObject(remote string) (fs.Object, error) {
o, err := f.Fs.NewObject(f.cipher.EncryptFileName(remote))
if err != nil {
return nil, err
}
return f.newObject(o), nil
}
// Put in to the remote path with the modTime given of the given size
//
// May create the object even if it returns an error - if so
// will return the object and the error, otherwise will return
// nil and the error
func (f *Fs) Put(in io.Reader, src fs.ObjectInfo) (fs.Object, error) {
wrappedIn, err := f.cipher.EncryptData(in)
if err != nil {
return nil, err
}
o, err := f.Fs.Put(wrappedIn, f.newObjectInfo(src))
if err != nil {
return nil, err
}
return f.newObject(o), nil
}
// Hashes returns the supported hash sets.
func (f *Fs) Hashes() fs.HashSet {
return fs.HashSet(fs.HashNone)
}
// Mkdir makes the directory (container, bucket)
//
// Shouldn't return an error if it already exists
func (f *Fs) Mkdir(dir string) error {
return f.Fs.Mkdir(f.cipher.EncryptDirName(dir))
}
// Rmdir removes the directory (container, bucket) if empty
//
// Return an error if it doesn't exist or isn't empty
func (f *Fs) Rmdir(dir string) error {
return f.Fs.Rmdir(f.cipher.EncryptDirName(dir))
}
// Purge all files in the root and the root directory
//
// Implement this if you have a way of deleting all the files
// quicker than just running Remove() on the result of List()
//
// Return an error if it doesn't exist
func (f *Fs) Purge() error {
do := f.Fs.Features().Purge
if do == nil {
return fs.ErrorCantPurge
}
return do()
}
// Copy src to this remote using server side copy operations.
//
// This is stored with the remote path given
//
// It returns the destination Object and a possible error
//
// Will only be called if src.Fs().Name() == f.Name()
//
// If it isn't possible then return fs.ErrorCantCopy
func (f *Fs) Copy(src fs.Object, remote string) (fs.Object, error) {
do := f.Fs.Features().Copy
if do == nil {
return nil, fs.ErrorCantCopy
}
o, ok := src.(*Object)
if !ok {
return nil, fs.ErrorCantCopy
}
oResult, err := do(o.Object, f.cipher.EncryptFileName(remote))
if err != nil {
return nil, err
}
return f.newObject(oResult), nil
}
// Move src to this remote using server side move operations.
//
// This is stored with the remote path given
//
// It returns the destination Object and a possible error
//
// Will only be called if src.Fs().Name() == f.Name()
//
// If it isn't possible then return fs.ErrorCantMove
func (f *Fs) Move(src fs.Object, remote string) (fs.Object, error) {
do := f.Fs.Features().Move
if do == nil {
return nil, fs.ErrorCantMove
}
o, ok := src.(*Object)
if !ok {
return nil, fs.ErrorCantMove
}
oResult, err := do(o.Object, f.cipher.EncryptFileName(remote))
if err != nil {
return nil, err
}
return f.newObject(oResult), nil
}
// DirMove moves src, srcRemote to this remote at dstRemote
// using server side move operations.
//
// Will only be called if src.Fs().Name() == f.Name()
//
// If it isn't possible then return fs.ErrorCantDirMove
//
// If destination exists then return fs.ErrorDirExists
func (f *Fs) DirMove(src fs.Fs, srcRemote, dstRemote string) error {
do := f.Fs.Features().DirMove
if do == nil {
return fs.ErrorCantDirMove
}
srcFs, ok := src.(*Fs)
if !ok {
fs.Debugf(srcFs, "Can't move directory - not same remote type")
return fs.ErrorCantDirMove
}
return do(srcFs.Fs, f.cipher.EncryptDirName(srcRemote), f.cipher.EncryptDirName(dstRemote))
}
// PutUnchecked uploads the object
//
// This will create a duplicate if we upload a new file without
// checking to see if there is one already - use Put() for that.
func (f *Fs) PutUnchecked(in io.Reader, src fs.ObjectInfo) (fs.Object, error) {
do := f.Fs.Features().PutUnchecked
if do == nil {
return nil, errors.New("can't PutUnchecked")
}
wrappedIn, err := f.cipher.EncryptData(in)
if err != nil {
return nil, err
}
o, err := do(wrappedIn, f.newObjectInfo(src))
if err != nil {
return nil, err
}
return f.newObject(o), nil
}
// CleanUp the trash in the Fs
//
// Implement this if you have a way of emptying the trash or
// otherwise cleaning up old versions of files.
func (f *Fs) CleanUp() error {
do := f.Fs.Features().CleanUp
if do == nil {
return errors.New("can't CleanUp")
}
return do()
}
// UnWrap returns the Fs that this Fs is wrapping
func (f *Fs) UnWrap() fs.Fs {
return f.Fs
}
// ComputeHash takes the nonce from o, and encrypts the contents of
// src with it, and calcuates the hash given by HashType on the fly
//
// Note that we break lots of encapsulation in this function.
func (f *Fs) ComputeHash(o *Object, src fs.Object, hashType fs.HashType) (hash string, err error) {
// Read the nonce - opening the file is sufficient to read the nonce in
in, err := o.Open()
if err != nil {
return "", errors.Wrap(err, "failed to read nonce")
}
nonce := in.(*decrypter).nonce
// fs.Debugf(o, "Read nonce % 2x", nonce)
// Check nonce isn't all zeros
isZero := true
for i := range nonce {
if nonce[i] != 0 {
isZero = false
}
}
if isZero {
fs.Errorf(o, "empty nonce read")
}
// Close in once we have read the nonce
err = in.Close()
if err != nil {
return "", errors.Wrap(err, "failed to close nonce read")
}
// Open the src for input
in, err = src.Open()
if err != nil {
return "", errors.Wrap(err, "failed to open src")
}
defer fs.CheckClose(in, &err)
// Now encrypt the src with the nonce
out, err := f.cipher.(*cipher).newEncrypter(in, &nonce)
if err != nil {
return "", errors.Wrap(err, "failed to make encrypter")
}
// pipe into hash
m := fs.NewMultiHasher()
_, err = io.Copy(m, out)
if err != nil {
return "", errors.Wrap(err, "failed to hash data")
}
return m.Sums()[hashType], nil
}
// Object describes a wrapped for being read from the Fs
//
// This decrypts the remote name and decrypts the data
type Object struct {
fs.Object
f *Fs
}
func (f *Fs) newObject(o fs.Object) *Object {
return &Object{
Object: o,
f: f,
}
}
// Fs returns read only access to the Fs that this object is part of
func (o *Object) Fs() fs.Info {
return o.f
}
// Return a string version
func (o *Object) String() string {
if o == nil {
return "<nil>"
}
return o.Remote()
}
// Remote returns the remote path
func (o *Object) Remote() string {
remote := o.Object.Remote()
decryptedName, err := o.f.cipher.DecryptFileName(remote)
if err != nil {
fs.Debugf(remote, "Undecryptable file name: %v", err)
return remote
}
return decryptedName
}
// Size returns the size of the file
func (o *Object) Size() int64 {
size, err := o.f.cipher.DecryptedSize(o.Object.Size())
if err != nil {
fs.Debugf(o, "Bad size for decrypt: %v", err)
}
return size
}
// Hash returns the selected checksum of the file
// If no checksum is available it returns ""
func (o *Object) Hash(hash fs.HashType) (string, error) {
return "", nil
}
// UnWrap returns the wrapped Object
func (o *Object) UnWrap() fs.Object {
return o.Object
}
// Open opens the file for read. Call Close() on the returned io.ReadCloser
func (o *Object) Open(options ...fs.OpenOption) (rc io.ReadCloser, err error) {
var offset int64
for _, option := range options {
switch x := option.(type) {
case *fs.SeekOption:
offset = x.Offset
default:
if option.Mandatory() {
fs.Logf(o, "Unsupported mandatory option: %v", option)
}
}
}
rc, err = o.f.cipher.DecryptDataSeek(func(underlyingOffset int64) (io.ReadCloser, error) {
if underlyingOffset == 0 {
// Open with no seek
return o.Object.Open()
}
// Open stream with a seek of underlyingOffset
return o.Object.Open(&fs.SeekOption{Offset: underlyingOffset})
}, offset)
if err != nil {
return nil, err
}
return rc, err
}
// Update in to the object with the modTime given of the given size
func (o *Object) Update(in io.Reader, src fs.ObjectInfo) error {
wrappedIn, err := o.f.cipher.EncryptData(in)
if err != nil {
return err
}
return o.Object.Update(wrappedIn, o.f.newObjectInfo(src))
}
// newDir returns a dir with the Name decrypted
func (f *Fs) newDir(dir *fs.Dir) *fs.Dir {
new := *dir
remote := dir.Name
decryptedRemote, err := f.cipher.DecryptDirName(remote)
if err != nil {
fs.Debugf(remote, "Undecryptable dir name: %v", err)
} else {
new.Name = decryptedRemote
}
return &new
}
// ObjectInfo describes a wrapped fs.ObjectInfo for being the source
//
// This encrypts the remote name and adjusts the size
type ObjectInfo struct {
fs.ObjectInfo
f *Fs
}
func (f *Fs) newObjectInfo(src fs.ObjectInfo) *ObjectInfo {
return &ObjectInfo{
ObjectInfo: src,
f: f,
}
}
// Fs returns read only access to the Fs that this object is part of
func (o *ObjectInfo) Fs() fs.Info {
return o.f
}
// Remote returns the remote path
func (o *ObjectInfo) Remote() string {
return o.f.cipher.EncryptFileName(o.ObjectInfo.Remote())
}
// Size returns the size of the file
func (o *ObjectInfo) Size() int64 {
return o.f.cipher.EncryptedSize(o.ObjectInfo.Size())
}
// Hash returns the selected checksum of the file
// If no checksum is available it returns ""
func (o *ObjectInfo) Hash(hash fs.HashType) (string, error) {
return "", nil
}
// ListOpts wraps a listopts decrypting the directory listing and
// replacing the Objects
type ListOpts struct {
fs.ListOpts
f *Fs
dir string // dir we are listing
mu sync.Mutex // to protect dirs
dirs map[string]struct{} // keep track of synthetic directory objects added
}
// Make a ListOpts wrapper
func (f *Fs) newListOpts(lo fs.ListOpts, dir string) *ListOpts {
if dir != "" {
dir += "/"
}
return &ListOpts{
ListOpts: lo,
f: f,
dir: dir,
dirs: make(map[string]struct{}),
}
}
// Level gets the recursion level for this listing.
//
// Fses may ignore this, but should implement it for improved efficiency if possible.
//
// Level 1 means list just the contents of the directory
//
// Each returned item must have less than level `/`s in.
func (lo *ListOpts) Level() int {
return lo.ListOpts.Level()
}
// Add an object to the output.
// If the function returns true, the operation has been aborted.
// Multiple goroutines can safely add objects concurrently.
func (lo *ListOpts) Add(obj fs.Object) (abort bool) {
remote := obj.Remote()
decryptedRemote, err := lo.f.cipher.DecryptFileName(remote)
if err != nil {
fs.Debugf(remote, "Skipping undecryptable file name: %v", err)
return lo.ListOpts.IsFinished()
}
if *cryptShowMapping {
fs.Logf(decryptedRemote, "Encrypts to %q", remote)
}
return lo.ListOpts.Add(lo.f.newObject(obj))
}
// AddDir adds a directory to the output.
// If the function returns true, the operation has been aborted.
// Multiple goroutines can safely add objects concurrently.
func (lo *ListOpts) AddDir(dir *fs.Dir) (abort bool) {
remote := dir.Name
decryptedRemote, err := lo.f.cipher.DecryptDirName(remote)
if err != nil {
fs.Debugf(remote, "Skipping undecryptable dir name: %v", err)
return lo.ListOpts.IsFinished()
}
if *cryptShowMapping {
fs.Logf(decryptedRemote, "Encrypts to %q", remote)
}
return lo.ListOpts.AddDir(lo.f.newDir(dir))
}
// IncludeDirectory returns whether this directory should be
// included in the listing (and recursed into or not).
func (lo *ListOpts) IncludeDirectory(remote string) bool {
decryptedRemote, err := lo.f.cipher.DecryptDirName(remote)
if err != nil {
fs.Debugf(remote, "Not including undecryptable directory name: %v", err)
return false
}
return lo.ListOpts.IncludeDirectory(decryptedRemote)
}
// Check the interfaces are satisfied
var (
_ fs.Fs = (*Fs)(nil)
_ fs.Purger = (*Fs)(nil)
_ fs.Copier = (*Fs)(nil)
_ fs.Mover = (*Fs)(nil)
_ fs.DirMover = (*Fs)(nil)
_ fs.PutUncheckeder = (*Fs)(nil)
_ fs.CleanUpper = (*Fs)(nil)
_ fs.UnWrapper = (*Fs)(nil)
_ fs.ObjectInfo = (*ObjectInfo)(nil)
_ fs.Object = (*Object)(nil)
_ fs.ListOpts = (*ListOpts)(nil)
)