forked from keybase/client
/
encrypteddb.go
136 lines (117 loc) · 2.79 KB
/
encrypteddb.go
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package encrypteddb
import (
"fmt"
"github.com/keybase/client/go/libkb"
"github.com/keybase/go-codec/codec"
"golang.org/x/crypto/nacl/secretbox"
"golang.org/x/net/context"
)
type DbFn func(g *libkb.GlobalContext) *libkb.JSONLocalDb
type KeyFn func(context.Context) ([32]byte, error)
type boxedData struct {
V int
N [24]byte
E []byte
}
// ***
// If we change this, make sure to update the key derivation reason for all callers of EncryptedDB!
// ***
const cryptoVersion = 1
// Handle to a db that encrypts values using nacl secretbox.
// Does not encrypt keys.
// Not threadsafe.
type EncryptedDB struct {
libkb.Contextified
getSecretBoxKey KeyFn
getDB DbFn
}
func New(g *libkb.GlobalContext, getDB DbFn, getSecretBoxKey KeyFn) *EncryptedDB {
return &EncryptedDB{
Contextified: libkb.NewContextified(g),
getDB: getDB,
getSecretBoxKey: getSecretBoxKey,
}
}
// Get a value
// Decodes into res
// Returns (found, err). Res is valid only if (found && err == nil)
func (i *EncryptedDB) Get(ctx context.Context, key libkb.DbKey, res interface{}) (bool, error) {
var err error
db := i.getDB(i.G())
b, found, err := db.GetRaw(key)
if err != nil {
return false, err
}
if !found {
return false, nil
}
// Decode encrypted box
var boxed boxedData
if err := decode(b, &boxed); err != nil {
return true, err
}
if boxed.V > cryptoVersion {
return true, fmt.Errorf("bad crypto version: %d current: %d", boxed.V,
cryptoVersion)
}
enckey, err := i.getSecretBoxKey(ctx)
if err != nil {
return true, err
}
pt, ok := secretbox.Open(nil, boxed.E, &boxed.N, &enckey)
if !ok {
return true, fmt.Errorf("failed to decrypt item")
}
if err = decode(pt, res); err != nil {
return true, err
}
return true, nil
}
func (i *EncryptedDB) Put(ctx context.Context, key libkb.DbKey, data interface{}) error {
db := i.getDB(i.G())
dat, err := encode(data)
if err != nil {
return err
}
enckey, err := i.getSecretBoxKey(ctx)
if err != nil {
return err
}
var nonce []byte
nonce, err = libkb.RandBytes(24)
if err != nil {
return err
}
var fnonce [24]byte
copy(fnonce[:], nonce)
sealed := secretbox.Seal(nil, dat, &fnonce, &enckey)
boxed := boxedData{
V: cryptoVersion,
E: sealed,
N: fnonce,
}
// Encode encrypted box
if dat, err = encode(boxed); err != nil {
return err
}
// Write out
if err = db.PutRaw(key, dat); err != nil {
return err
}
return nil
}
func encode(input interface{}) ([]byte, error) {
mh := codec.MsgpackHandle{WriteExt: true}
var data []byte
enc := codec.NewEncoderBytes(&data, &mh)
if err := enc.Encode(input); err != nil {
return nil, err
}
return data, nil
}
func decode(data []byte, res interface{}) error {
mh := codec.MsgpackHandle{WriteExt: true}
dec := codec.NewDecoderBytes(data, &mh)
err := dec.Decode(res)
return err
}