// decrypt authenticates and decrypts ciphertext and stores the result in
// plaintext.
func (r *Repository) decryptTo(plaintext, ciphertext []byte) ([]byte, error) {
if r.key == nil {
return nil, errors.New("key for repository not set")
}
return crypto.Decrypt(r.key, nil, ciphertext)
}
func TestEncryptWriter(t *testing.T) {
k := crypto.NewRandomKey()
tests := []int{5, 23, 2<<18 + 23, 1 << 20}
if testLargeCrypto {
tests = append(tests, 7<<20+123)
}
for _, size := range tests {
data := Random(42, size)
buf := bytes.NewBuffer(nil)
wr := crypto.EncryptTo(k, buf)
_, err := io.Copy(wr, bytes.NewReader(data))
OK(t, err)
OK(t, wr.Close())
ciphertext := buf.Bytes()
l := len(data) + crypto.Extension
Assert(t, len(ciphertext) == l,
"wrong ciphertext length: expected %d, got %d",
l, len(ciphertext))
// decrypt with default function
plaintext, err := crypto.Decrypt(k, []byte{}, ciphertext)
OK(t, err)
Assert(t, bytes.Equal(data, plaintext),
"wrong plaintext after decryption: expected %02x, got %02x",
data, plaintext)
}
}
func TestEncryptDecrypt(t *testing.T) {
k := crypto.NewRandomKey()
tests := []int{5, 23, 2<<18 + 23, 1 << 20}
if testLargeCrypto {
tests = append(tests, 7<<20+123)
}
for _, size := range tests {
data := Random(42, size)
buf := make([]byte, size+crypto.Extension)
ciphertext, err := crypto.Encrypt(k, buf, data)
OK(t, err)
Assert(t, len(ciphertext) == len(data)+crypto.Extension,
"ciphertext length does not match: want %d, got %d",
len(data)+crypto.Extension, len(ciphertext))
plaintext, err := crypto.Decrypt(k, nil, ciphertext)
OK(t, err)
Assert(t, len(plaintext) == len(data),
"plaintext length does not match: want %d, got %d",
len(data), len(plaintext))
Equals(t, plaintext, data)
}
}
// List returns the list of entries found in a pack file.
func List(k *crypto.Key, rd io.ReaderAt, size int64) (entries []restic.Blob, err error) {
buf, err := readHeader(rd, size)
if err != nil {
return nil, err
}
n, err := crypto.Decrypt(k, buf, buf)
if err != nil {
return nil, err
}
buf = buf[:n]
hdrRd := bytes.NewReader(buf)
pos := uint(0)
for {
e := headerEntry{}
err = binary.Read(hdrRd, binary.LittleEndian, &e)
if errors.Cause(err) == io.EOF {
break
}
if err != nil {
return nil, errors.Wrap(err, "binary.Read")
}
entry := restic.Blob{
Length: uint(e.Length),
ID: e.ID,
Offset: pos,
}
switch e.Type {
case 0:
entry.Type = restic.DataBlob
case 1:
entry.Type = restic.TreeBlob
default:
return nil, errors.Errorf("invalid type %d", e.Type)
}
entries = append(entries, entry)
pos += uint(e.Length)
}
return entries, nil
}
// OpenKey tries do decrypt the key specified by name with the given password.
func OpenKey(s *Repository, name string, password string) (*Key, error) {
k, err := LoadKey(s, name)
if err != nil {
debug.Log("LoadKey(%v) returned error %v", name[:12], err)
return nil, err
}
// check KDF
if k.KDF != "scrypt" {
return nil, errors.New("only supported KDF is scrypt()")
}
// derive user key
params := crypto.KDFParams{
N: k.N,
R: k.R,
P: k.P,
}
k.user, err = crypto.KDF(params, k.Salt, password)
if err != nil {
return nil, errors.Wrap(err, "crypto.KDF")
}
// decrypt master keys
buf := make([]byte, len(k.Data))
n, err := crypto.Decrypt(k.user, buf, k.Data)
if err != nil {
return nil, err
}
buf = buf[:n]
// restore json
k.master = &crypto.Key{}
err = json.Unmarshal(buf, k.master)
if err != nil {
debug.Log("Unmarshal() returned error %v", err)
return nil, errors.Wrap(err, "Unmarshal")
}
k.name = name
if !k.Valid() {
return nil, errors.New("Invalid key for repository")
}
return k, nil
}
// checkPack reads a pack and checks the integrity of all blobs.
func checkPack(r restic.Repository, id restic.ID) error {
debug.Log("checking pack %v", id.Str())
h := restic.Handle{Type: restic.DataFile, Name: id.String()}
buf, err := backend.LoadAll(r.Backend(), h, nil)
if err != nil {
return err
}
hash := restic.Hash(buf)
if !hash.Equal(id) {
debug.Log("Pack ID does not match, want %v, got %v", id.Str(), hash.Str())
return errors.Errorf("Pack ID does not match, want %v, got %v", id.Str(), hash.Str())
}
blobs, err := pack.List(r.Key(), bytes.NewReader(buf), int64(len(buf)))
if err != nil {
return err
}
var errs []error
for i, blob := range blobs {
debug.Log(" check blob %d: %v", i, blob.ID.Str())
plainBuf := make([]byte, blob.Length)
n, err := crypto.Decrypt(r.Key(), plainBuf, buf[blob.Offset:blob.Offset+blob.Length])
if err != nil {
debug.Log(" error decrypting blob %v: %v", blob.ID.Str(), err)
errs = append(errs, errors.Errorf("blob %v: %v", i, err))
continue
}
plainBuf = plainBuf[:n]
hash := restic.Hash(plainBuf)
if !hash.Equal(blob.ID) {
debug.Log(" Blob ID does not match, want %v, got %v", blob.ID.Str(), hash.Str())
errs = append(errs, errors.Errorf("Blob ID does not match, want %v, got %v", blob.ID.Str(), hash.Str()))
continue
}
}
if len(errs) > 0 {
return errors.Errorf("pack %v contains %v errors: %v", id.Str(), len(errs), errs)
}
return nil
}
// checkPack reads a pack and checks the integrity of all blobs.
func checkPack(r *repository.Repository, id backend.ID) error {
debug.Log("Checker.checkPack", "checking pack %v", id.Str())
h := backend.Handle{Type: backend.Data, Name: id.String()}
buf, err := backend.LoadAll(r.Backend(), h, nil)
if err != nil {
return err
}
hash := backend.Hash(buf)
if !hash.Equal(id) {
debug.Log("Checker.checkPack", "Pack ID does not match, want %v, got %v", id.Str(), hash.Str())
return fmt.Errorf("Pack ID does not match, want %v, got %v", id.Str(), hash.Str())
}
unpacker, err := pack.NewUnpacker(r.Key(), bytes.NewReader(buf))
if err != nil {
return err
}
var errs []error
for i, blob := range unpacker.Entries {
debug.Log("Checker.checkPack", " check blob %d: %v", i, blob.ID.Str())
plainBuf := make([]byte, blob.Length)
plainBuf, err = crypto.Decrypt(r.Key(), plainBuf, buf[blob.Offset:blob.Offset+blob.Length])
if err != nil {
debug.Log("Checker.checkPack", " error decrypting blob %v: %v", blob.ID.Str(), err)
errs = append(errs, fmt.Errorf("blob %v: %v", i, err))
continue
}
hash := backend.Hash(plainBuf)
if !hash.Equal(blob.ID) {
debug.Log("Checker.checkPack", " Blob ID does not match, want %v, got %v", blob.ID.Str(), hash.Str())
errs = append(errs, fmt.Errorf("Blob ID does not match, want %v, got %v", blob.ID.Str(), hash.Str()))
continue
}
}
if len(errs) > 0 {
return fmt.Errorf("pack %v contains %v errors: %v", id.Str(), len(errs), errs)
}
return nil
}
func TestSameBuffer(t *testing.T) {
k := crypto.NewRandomKey()
size := 600
data := make([]byte, size)
_, err := io.ReadFull(rand.Reader, data)
OK(t, err)
ciphertext := make([]byte, 0, size+crypto.Extension)
ciphertext, err = crypto.Encrypt(k, ciphertext, data)
OK(t, err)
// use the same buffer for decryption
ciphertext, err = crypto.Decrypt(k, ciphertext, ciphertext)
OK(t, err)
Assert(t, bytes.Equal(ciphertext, data),
"wrong plaintext returned")
}
func BenchmarkDecrypt(b *testing.B) {
size := 8 << 20 // 8MiB
data := make([]byte, size)
k := crypto.NewRandomKey()
plaintext := make([]byte, size)
ciphertext := make([]byte, size+crypto.Extension)
ciphertext, err := crypto.Encrypt(k, ciphertext, data)
OK(b, err)
b.ResetTimer()
b.SetBytes(int64(size))
for i := 0; i < b.N; i++ {
plaintext, err = crypto.Decrypt(k, plaintext, ciphertext)
OK(b, err)
}
}
func TestCornerCases(t *testing.T) {
k := crypto.NewRandomKey()
// nil plaintext should encrypt to the empty string
// nil ciphertext should allocate a new slice for the ciphertext
c, err := crypto.Encrypt(k, nil, nil)
OK(t, err)
Assert(t, len(c) == crypto.Extension,
"wrong length returned for ciphertext, expected 0, got %d",
len(c))
// this should decrypt to nil
p, err := crypto.Decrypt(k, nil, c)
OK(t, err)
Equals(t, []byte(nil), p)
// test encryption for same slice, this should return an error
_, err = crypto.Encrypt(k, c, c)
Equals(t, crypto.ErrInvalidCiphertext, err)
}
func TestSmallBuffer(t *testing.T) {
k := crypto.NewRandomKey()
size := 600
data := make([]byte, size)
_, err := io.ReadFull(rand.Reader, data)
OK(t, err)
ciphertext := make([]byte, size/2)
ciphertext, err = crypto.Encrypt(k, ciphertext, data)
// this must extend the slice
Assert(t, cap(ciphertext) > size/2,
"expected extended slice, but capacity is only %d bytes",
cap(ciphertext))
// check for the correct plaintext
plaintext, err := crypto.Decrypt(k, nil, ciphertext)
OK(t, err)
Assert(t, bytes.Equal(plaintext, data),
"wrong plaintext returned")
}
func TestLargeEncrypt(t *testing.T) {
if !testLargeCrypto {
t.SkipNow()
}
k := crypto.NewRandomKey()
for _, size := range []int{chunker.MaxSize, chunker.MaxSize + 1, chunker.MaxSize + 1<<20} {
data := make([]byte, size)
_, err := io.ReadFull(rand.Reader, data)
OK(t, err)
ciphertext, err := crypto.Encrypt(k, make([]byte, size+crypto.Extension), data)
OK(t, err)
plaintext, err := crypto.Decrypt(k, []byte{}, ciphertext)
OK(t, err)
Equals(t, plaintext, data)
}
}
// OpenKey tries do decrypt the key specified by name with the given password.
func OpenKey(s *Repository, name string, password string) (*Key, error) {
k, err := LoadKey(s, name)
if err != nil {
debug.Log("OpenKey", "LoadKey(%v) returned error %v", name[:12], err)
return nil, err
}
// check KDF
if k.KDF != "scrypt" {
return nil, errors.New("only supported KDF is scrypt()")
}
// derive user key
k.user, err = crypto.KDF(k.N, k.R, k.P, k.Salt, password)
if err != nil {
return nil, err
}
// decrypt master keys
buf, err := crypto.Decrypt(k.user, []byte{}, k.Data)
if err != nil {
return nil, err
}
// restore json
k.master = &crypto.Key{}
err = json.Unmarshal(buf, k.master)
if err != nil {
debug.Log("OpenKey", "Unmarshal() returned error %v", err)
return nil, err
}
k.name = name
if !k.Valid() {
return nil, errors.New("Invalid key for repository")
}
return k, nil
}
// Repack takes a list of packs together with a list of blobs contained in
// these packs. Each pack is loaded and the blobs listed in keepBlobs is saved
// into a new pack. Afterwards, the packs are removed. This operation requires
// an exclusive lock on the repo.
func Repack(repo restic.Repository, packs restic.IDSet, keepBlobs restic.BlobSet) (err error) {
debug.Log("repacking %d packs while keeping %d blobs", len(packs), len(keepBlobs))
buf := make([]byte, 0, maxPackSize)
for packID := range packs {
// load the complete pack
h := restic.Handle{Type: restic.DataFile, Name: packID.String()}
l, err := repo.Backend().Load(h, buf[:cap(buf)], 0)
if errors.Cause(err) == io.ErrUnexpectedEOF {
err = nil
buf = buf[:l]
}
if err != nil {
return err
}
debug.Log("pack %v loaded (%d bytes)", packID.Str(), len(buf))
blobs, err := pack.List(repo.Key(), bytes.NewReader(buf), int64(len(buf)))
if err != nil {
return err
}
debug.Log("processing pack %v, blobs: %v", packID.Str(), len(blobs))
var plaintext []byte
for _, entry := range blobs {
h := restic.BlobHandle{ID: entry.ID, Type: entry.Type}
if !keepBlobs.Has(h) {
continue
}
debug.Log(" process blob %v", h)
ciphertext := buf[entry.Offset : entry.Offset+entry.Length]
plaintext = plaintext[:len(plaintext)]
if len(plaintext) < len(ciphertext) {
plaintext = make([]byte, len(ciphertext))
}
debug.Log(" ciphertext %d, plaintext %d", len(plaintext), len(ciphertext))
n, err := crypto.Decrypt(repo.Key(), plaintext, ciphertext)
if err != nil {
return err
}
plaintext = plaintext[:n]
_, err = repo.SaveBlob(entry.Type, plaintext, entry.ID)
if err != nil {
return err
}
debug.Log(" saved blob %v", entry.ID.Str())
keepBlobs.Delete(h)
}
}
if err := repo.Flush(); err != nil {
return err
}
for packID := range packs {
err := repo.Backend().Remove(restic.DataFile, packID.String())
if err != nil {
debug.Log("error removing pack %v: %v", packID.Str(), err)
return err
}
debug.Log("removed pack %v", packID.Str())
}
return nil
}
