// SaveJSONUnpacked serialises item as JSON and encrypts and saves it in the
// backend as type t, without a pack. It returns the storage hash.
func (s *Repository) SaveJSONUnpacked(t backend.Type, item interface{}) (backend.ID, error) {
// create file
blob, err := s.be.Create()
if err != nil {
return nil, err
}
debug.Log("Repo.SaveJSONUnpacked", "create new file %p", blob)
// hash
hw := backend.NewHashingWriter(blob, sha256.New())
// encrypt blob
ewr := crypto.EncryptTo(s.key, hw)
enc := json.NewEncoder(ewr)
err = enc.Encode(item)
if err != nil {
return nil, fmt.Errorf("json.Encode: %v", err)
}
err = ewr.Close()
if err != nil {
return nil, err
}
// finalize blob in the backend
sid := backend.ID(hw.Sum(nil))
err = blob.Finalize(t, sid.String())
if err != nil {
return nil, err
}
return sid, nil
}
func TestHashingWriter(t *testing.T) {
tests := []int{5, 23, 2<<18 + 23, 1 << 20}
for _, size := range tests {
data := make([]byte, size)
_, err := io.ReadFull(rand.Reader, data)
if err != nil {
t.Fatalf("ReadFull: %v", err)
}
expectedHash := sha256.Sum256(data)
wr := backend.NewHashingWriter(ioutil.Discard, sha256.New())
n, err := io.Copy(wr, bytes.NewReader(data))
OK(t, err)
Assert(t, n == int64(size),
"HashAppendWriter: invalid number of bytes written: got %d, expected %d",
n, size)
Assert(t, wr.Size() == size,
"HashAppendWriter: invalid number of bytes returned: got %d, expected %d",
wr.Size, size)
resultingHash := wr.Sum(nil)
Assert(t, bytes.Equal(expectedHash[:], resultingHash),
"HashAppendWriter: hashes do not match: expected %02x, got %02x",
expectedHash, resultingHash)
}
}
// CreateEncryptedBlob returns a BlobWriter that encrypts and saves the data
// written to it in the backend. After Close() was called, ID() returns the
// backend.ID.
func (r *Repository) CreateEncryptedBlob(t backend.Type) (*BlobWriter, error) {
blob, err := r.be.Create()
if err != nil {
return nil, err
}
// hash
hw := backend.NewHashingWriter(blob, sha256.New())
// encrypt blob
ewr := crypto.EncryptTo(r.key, hw)
return &BlobWriter{t: t, blob: blob, hw: hw, ewr: ewr}, nil
}
// SaveJSONUnpacked serialises item as JSON and encrypts and saves it in the
// backend as type t, without a pack. It returns the storage hash.
func (r *Repository) SaveJSONUnpacked(t backend.Type, item interface{}) (backend.ID, error) {
// create file
blob, err := r.be.Create()
if err != nil {
return backend.ID{}, err
}
debug.Log("Repo.SaveJSONUnpacked", "create new blob %v", t)
// hash
hw := backend.NewHashingWriter(blob, sha256.New())
// encrypt blob
ewr := crypto.EncryptTo(r.key, hw)
enc := json.NewEncoder(ewr)
err = enc.Encode(item)
if err != nil {
return backend.ID{}, fmt.Errorf("json.Encode: %v", err)
}
err = ewr.Close()
if err != nil {
return backend.ID{}, err
}
// finalize blob in the backend
hash := hw.Sum(nil)
sid := backend.ID{}
copy(sid[:], hash)
err = blob.Finalize(t, sid.String())
if err != nil {
debug.Log("Repo.SaveJSONUnpacked", "error saving blob %v as %v: %v", t, sid, err)
return backend.ID{}, err
}
debug.Log("Repo.SaveJSONUnpacked", "new blob %v saved as %v", t, sid)
return sid, nil
}
// SaveIndex saves all new packs in the index in the backend, returned is the
// storage ID.
func (r *Repository) SaveIndex() (backend.ID, error) {
debug.Log("Repo.SaveIndex", "Saving index")
// create blob
blob, err := r.be.Create()
if err != nil {
return backend.ID{}, err
}
debug.Log("Repo.SaveIndex", "create new pack %p", blob)
// hash
hw := backend.NewHashingWriter(blob, sha256.New())
// encrypt blob
ewr := crypto.EncryptTo(r.key, hw)
err = r.idx.Encode(ewr)
if err != nil {
return backend.ID{}, err
}
err = ewr.Close()
if err != nil {
return backend.ID{}, err
}
// finalize blob in the backend
sid := backend.ID{}
copy(sid[:], hw.Sum(nil))
err = blob.Finalize(backend.Index, sid.String())
if err != nil {
return backend.ID{}, err
}
debug.Log("Repo.SaveIndex", "Saved index as %v", sid.Str())
return sid, nil
}
// AddKey adds a new key to an already existing repository.
func AddKey(s *Repository, password string, template *crypto.Key) (*Key, error) {
// fill meta data about key
newkey := &Key{
Created: time.Now(),
KDF: "scrypt",
N: scryptN,
R: scryptR,
P: scryptP,
}
hn, err := os.Hostname()
if err == nil {
newkey.Hostname = hn
}
usr, err := user.Current()
if err == nil {
newkey.Username = usr.Username
}
// generate random salt
newkey.Salt = make([]byte, scryptSaltsize)
n, err := rand.Read(newkey.Salt)
if n != scryptSaltsize || err != nil {
panic("unable to read enough random bytes for salt")
}
// call KDF to derive user key
newkey.user, err = crypto.KDF(newkey.N, newkey.R, newkey.P, newkey.Salt, password)
if err != nil {
return nil, err
}
if template == nil {
// generate new random master keys
newkey.master = crypto.NewRandomKey()
} else {
// copy master keys from old key
newkey.master = template
}
// encrypt master keys (as json) with user key
buf, err := json.Marshal(newkey.master)
if err != nil {
return nil, err
}
newkey.Data, err = crypto.Encrypt(newkey.user, nil, buf)
// dump as json
buf, err = json.Marshal(newkey)
if err != nil {
return nil, err
}
// store in repository and return
blob, err := s.be.Create()
if err != nil {
return nil, err
}
plainhw := backend.NewHashingWriter(blob, sha256.New())
_, err = plainhw.Write(buf)
if err != nil {
return nil, err
}
name := hex.EncodeToString(plainhw.Sum(nil))
err = blob.Finalize(backend.Key, name)
if err != nil {
return nil, err
}
newkey.name = name
return newkey, nil
}
// NewPacker returns a new Packer that can be used to pack blobs
// together.
func NewPacker(k *crypto.Key, w io.Writer) *Packer {
return &Packer{k: k, wr: w, hw: backend.NewHashingWriter(w, sha256.New())}
}