commit eb910ba14f2a5493b85ef65efcc46cdeacfa787a
parent cb4c8abe1c121ee8f7c39de6b4b1824821542b7e
Author: ThomasV <thomasv@electrum.org>
Date: Thu, 18 Jun 2020 15:17:13 +0200
Merge pull request #6236 from spesmilo/channel_backup_version
Channel backup version
Diffstat:
7 files changed, 61 insertions(+), 17 deletions(-)
diff --git a/electrum/crypto.py b/electrum/crypto.py
@@ -189,23 +189,19 @@ def _hash_password(password: Union[bytes, str], *, version: int) -> bytes:
raise UnexpectedPasswordHashVersion(version)
-def pw_encode_bytes(data: bytes, password: Union[bytes, str], *, version: int) -> str:
- """plaintext bytes -> base64 ciphertext"""
+def _pw_encode_raw(data: bytes, password: Union[bytes, str], *, version: int) -> bytes:
if version not in KNOWN_PW_HASH_VERSIONS:
raise UnexpectedPasswordHashVersion(version)
# derive key from password
secret = _hash_password(password, version=version)
# encrypt given data
ciphertext = EncodeAES_bytes(secret, data)
- ciphertext_b64 = base64.b64encode(ciphertext)
- return ciphertext_b64.decode('utf8')
+ return ciphertext
-def pw_decode_bytes(data: str, password: Union[bytes, str], *, version: int) -> bytes:
- """base64 ciphertext -> plaintext bytes"""
+def _pw_decode_raw(data_bytes: bytes, password: Union[bytes, str], *, version: int) -> bytes:
if version not in KNOWN_PW_HASH_VERSIONS:
raise UnexpectedPasswordHashVersion(version)
- data_bytes = bytes(base64.b64decode(data))
# derive key from password
secret = _hash_password(password, version=version)
# decrypt given data
@@ -216,6 +212,46 @@ def pw_decode_bytes(data: str, password: Union[bytes, str], *, version: int) ->
return d
+def pw_encode_bytes(data: bytes, password: Union[bytes, str], *, version: int) -> str:
+ """plaintext bytes -> base64 ciphertext"""
+ ciphertext = _pw_encode_raw(data, password, version=version)
+ ciphertext_b64 = base64.b64encode(ciphertext)
+ return ciphertext_b64.decode('utf8')
+
+
+def pw_decode_bytes(data: str, password: Union[bytes, str], *, version:int) -> bytes:
+ """base64 ciphertext -> plaintext bytes"""
+ if version not in KNOWN_PW_HASH_VERSIONS:
+ raise UnexpectedPasswordHashVersion(version)
+ data_bytes = bytes(base64.b64decode(data))
+ return _pw_decode_raw(data_bytes, password, version=version)
+
+
+def pw_encode_with_version_and_mac(data: bytes, password: Union[bytes, str]) -> str:
+ """plaintext bytes -> base64 ciphertext"""
+ # https://crypto.stackexchange.com/questions/202/should-we-mac-then-encrypt-or-encrypt-then-mac
+ # Encrypt-and-MAC. The MAC will be used to detect invalid passwords
+ version = PW_HASH_VERSION_LATEST
+ mac = sha256(data)[0:4]
+ ciphertext = _pw_encode_raw(data, password, version=version)
+ ciphertext_b64 = base64.b64encode(bytes([version]) + ciphertext + mac)
+ return ciphertext_b64.decode('utf8')
+
+
+def pw_decode_with_version_and_mac(data: str, password: Union[bytes, str]) -> bytes:
+ """base64 ciphertext -> plaintext bytes"""
+ data_bytes = bytes(base64.b64decode(data))
+ version = int(data_bytes[0])
+ encrypted = data_bytes[1:-4]
+ mac = data_bytes[-4:]
+ if version not in KNOWN_PW_HASH_VERSIONS:
+ raise UnexpectedPasswordHashVersion(version)
+ decrypted = _pw_decode_raw(encrypted, password, version=version)
+ if sha256(decrypted)[0:4] != mac:
+ raise InvalidPassword()
+ return decrypted
+
+
def pw_encode(data: str, password: Union[bytes, str, None], *, version: int) -> str:
"""plaintext str -> base64 ciphertext"""
if not password:
diff --git a/electrum/gui/kivy/main_window.py b/electrum/gui/kivy/main_window.py
@@ -415,7 +415,7 @@ class ElectrumWindow(App):
self.set_URI(data)
return
if data.startswith('channel_backup:'):
- self.import_channel_backup(data[15:])
+ self.import_channel_backup(data)
return
bolt11_invoice = maybe_extract_bolt11_invoice(data)
if bolt11_invoice is not None:
diff --git a/electrum/gui/kivy/uix/dialogs/lightning_channels.py b/electrum/gui/kivy/uix/dialogs/lightning_channels.py
@@ -379,7 +379,7 @@ class ChannelDetailsPopup(Popup):
_("Please note that channel backups cannot be used to restore your channels."),
_("If you lose your wallet file, the only thing you can do with a backup is to request your channel to be closed, so that your funds will be sent on-chain."),
])
- self.app.qr_dialog(_("Channel Backup " + self.chan.short_id_for_GUI()), 'channel_backup:'+text, help_text=help_text)
+ self.app.qr_dialog(_("Channel Backup " + self.chan.short_id_for_GUI()), text, help_text=help_text)
def force_close(self):
Question(_('Force-close channel?'), self._force_close).open()
diff --git a/electrum/gui/qt/channels_list.py b/electrum/gui/qt/channels_list.py
@@ -132,7 +132,7 @@ class ChannelsList(MyTreeView):
_("If you lose your wallet file, the only thing you can do with a backup is to request your channel to be closed, so that your funds will be sent on-chain."),
])
data = self.lnworker.export_channel_backup(channel_id)
- self.main_window.show_qrcode('channel_backup:' + data, 'channel backup', help_text=msg)
+ self.main_window.show_qrcode(data, 'channel backup', help_text=msg)
def request_force_close(self, channel_id):
def task():
diff --git a/electrum/gui/qt/main_window.py b/electrum/gui/qt/main_window.py
@@ -2617,7 +2617,7 @@ class ElectrumWindow(QMainWindow, MessageBoxMixin, Logger):
self.pay_to_URI(data)
return
if data.startswith('channel_backup:'):
- self.import_channel_backup(data[15:])
+ self.import_channel_backup(data)
return
# else if the user scanned an offline signed tx
tx = self.tx_from_text(data)
diff --git a/electrum/lnutil.py b/electrum/lnutil.py
@@ -154,6 +154,8 @@ class ChannelConstraints(StoredObject):
is_initiator = attr.ib(type=bool) # note: sometimes also called "funder"
funding_txn_minimum_depth = attr.ib(type=int)
+
+CHANNEL_BACKUP_VERSION = 0
@attr.s
class ChannelBackupStorage(StoredObject):
node_id = attr.ib(type=bytes, converter=hex_to_bytes)
@@ -179,6 +181,7 @@ class ChannelBackupStorage(StoredObject):
def to_bytes(self):
vds = BCDataStream()
+ vds.write_int16(CHANNEL_BACKUP_VERSION)
vds.write_boolean(self.is_initiator)
vds.write_bytes(self.privkey, 32)
vds.write_bytes(self.channel_seed, 32)
@@ -198,6 +201,9 @@ class ChannelBackupStorage(StoredObject):
def from_bytes(s):
vds = BCDataStream()
vds.write(s)
+ version = vds.read_int16()
+ if version != CHANNEL_BACKUP_VERSION:
+ raise Exception(f"unknown version for channel backup: {version}")
return ChannelBackupStorage(
is_initiator = bool(vds.read_bytes(1)),
privkey = vds.read_bytes(32).hex(),
diff --git a/electrum/lnworker.py b/electrum/lnworker.py
@@ -66,7 +66,7 @@ from .lnrouter import (RouteEdge, LNPaymentRoute, LNPaymentPath, is_route_sane_t
from .address_synchronizer import TX_HEIGHT_LOCAL
from . import lnsweep
from .lnwatcher import LNWalletWatcher
-from .crypto import pw_encode_bytes, pw_decode_bytes, PW_HASH_VERSION_LATEST
+from .crypto import pw_encode_with_version_and_mac, pw_decode_with_version_and_mac
from .lnutil import ChannelBackupStorage
from .lnchannel import ChannelBackup
from .channel_db import UpdateStatus
@@ -1396,9 +1396,9 @@ class LNWallet(LNWorker):
xpub = self.wallet.get_fingerprint()
backup_bytes = self.create_channel_backup(channel_id).to_bytes()
assert backup_bytes == ChannelBackupStorage.from_bytes(backup_bytes).to_bytes(), "roundtrip failed"
- encrypted = pw_encode_bytes(backup_bytes, xpub, version=PW_HASH_VERSION_LATEST)
- assert backup_bytes == pw_decode_bytes(encrypted, xpub, version=PW_HASH_VERSION_LATEST), "encrypt failed"
- return encrypted
+ encrypted = pw_encode_with_version_and_mac(backup_bytes, xpub)
+ assert backup_bytes == pw_decode_with_version_and_mac(encrypted, xpub), "encrypt failed"
+ return 'channel_backup:' + encrypted
class LNBackups(Logger):
@@ -1449,9 +1449,11 @@ class LNBackups(Logger):
self.lnwatcher.stop()
self.lnwatcher = None
- def import_channel_backup(self, encrypted):
+ def import_channel_backup(self, data):
+ assert data.startswith('channel_backup:')
+ encrypted = data[15:]
xpub = self.wallet.get_fingerprint()
- decrypted = pw_decode_bytes(encrypted, xpub, version=PW_HASH_VERSION_LATEST)
+ decrypted = pw_decode_with_version_and_mac(encrypted, xpub)
cb_storage = ChannelBackupStorage.from_bytes(decrypted)
channel_id = cb_storage.channel_id().hex()
d = self.db.get_dict("channel_backups")
