1
0
Files
electrum/electrum/storage.py
SomberNight c463f5e23d password unification refactor: move methods from wallet to daemon
Note in particular that check_password_for_directory was not safe to use while the daemon had wallets loaded,
as the same file would have two corresponding Wallet() instances in memory. This was specifically handled in
the kivy GUI, on the caller side, by stopping-before and reloading-after the wallets; but it was dirty to
have the caller handle this.
2022-07-06 19:57:27 +02:00

216 lines
7.8 KiB
Python

#!/usr/bin/env python
#
# Electrum - lightweight Bitcoin client
# Copyright (C) 2015 Thomas Voegtlin
#
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation files
# (the "Software"), to deal in the Software without restriction,
# including without limitation the rights to use, copy, modify, merge,
# publish, distribute, sublicense, and/or sell copies of the Software,
# and to permit persons to whom the Software is furnished to do so,
# subject to the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
import os
import threading
import stat
import hashlib
import base64
import zlib
from enum import IntEnum
from . import ecc
from .util import (profiler, InvalidPassword, WalletFileException, bfh, standardize_path,
test_read_write_permissions)
from .wallet_db import WalletDB
from .logging import Logger
def get_derivation_used_for_hw_device_encryption():
return ("m"
"/4541509'" # ascii 'ELE' as decimal ("BIP43 purpose")
"/1112098098'") # ascii 'BIE2' as decimal
class StorageEncryptionVersion(IntEnum):
PLAINTEXT = 0
USER_PASSWORD = 1
XPUB_PASSWORD = 2
class StorageReadWriteError(Exception): pass
# TODO: Rename to Storage
class WalletStorage(Logger):
def __init__(self, path):
Logger.__init__(self)
self.path = standardize_path(path)
self._file_exists = bool(self.path and os.path.exists(self.path))
self.logger.info(f"wallet path {self.path}")
self.pubkey = None
self.decrypted = ''
try:
test_read_write_permissions(self.path)
except IOError as e:
raise StorageReadWriteError(e) from e
if self.file_exists():
with open(self.path, "r", encoding='utf-8') as f:
self.raw = f.read()
self._encryption_version = self._init_encryption_version()
else:
self.raw = ''
self._encryption_version = StorageEncryptionVersion.PLAINTEXT
def read(self):
return self.decrypted if self.is_encrypted() else self.raw
def write(self, data: str) -> None:
s = self.encrypt_before_writing(data)
temp_path = "%s.tmp.%s" % (self.path, os.getpid())
with open(temp_path, "w", encoding='utf-8') as f:
f.write(s)
f.flush()
os.fsync(f.fileno())
try:
mode = os.stat(self.path).st_mode
except FileNotFoundError:
mode = stat.S_IREAD | stat.S_IWRITE
# assert that wallet file does not exist, to prevent wallet corruption (see issue #5082)
if not self.file_exists():
assert not os.path.exists(self.path)
os.replace(temp_path, self.path)
os.chmod(self.path, mode)
self._file_exists = True
self.logger.info(f"saved {self.path}")
def file_exists(self) -> bool:
return self._file_exists
def is_past_initial_decryption(self):
"""Return if storage is in a usable state for normal operations.
The value is True exactly
if encryption is disabled completely (self.is_encrypted() == False),
or if encryption is enabled but the contents have already been decrypted.
"""
return not self.is_encrypted() or bool(self.pubkey)
def is_encrypted(self):
"""Return if storage encryption is currently enabled."""
return self.get_encryption_version() != StorageEncryptionVersion.PLAINTEXT
def is_encrypted_with_user_pw(self):
return self.get_encryption_version() == StorageEncryptionVersion.USER_PASSWORD
def is_encrypted_with_hw_device(self):
return self.get_encryption_version() == StorageEncryptionVersion.XPUB_PASSWORD
def get_encryption_version(self):
"""Return the version of encryption used for this storage.
0: plaintext / no encryption
ECIES, private key derived from a password,
1: password is provided by user
2: password is derived from an xpub; used with hw wallets
"""
return self._encryption_version
def _init_encryption_version(self):
try:
magic = base64.b64decode(self.raw)[0:4]
if magic == b'BIE1':
return StorageEncryptionVersion.USER_PASSWORD
elif magic == b'BIE2':
return StorageEncryptionVersion.XPUB_PASSWORD
else:
return StorageEncryptionVersion.PLAINTEXT
except:
return StorageEncryptionVersion.PLAINTEXT
@staticmethod
def get_eckey_from_password(password):
if password is None:
password = ""
secret = hashlib.pbkdf2_hmac('sha512', password.encode('utf-8'), b'', iterations=1024)
ec_key = ecc.ECPrivkey.from_arbitrary_size_secret(secret)
return ec_key
def _get_encryption_magic(self):
v = self._encryption_version
if v == StorageEncryptionVersion.USER_PASSWORD:
return b'BIE1'
elif v == StorageEncryptionVersion.XPUB_PASSWORD:
return b'BIE2'
else:
raise WalletFileException('no encryption magic for version: %s' % v)
def decrypt(self, password) -> None:
"""Raises an InvalidPassword exception on invalid password"""
if self.is_past_initial_decryption():
return
ec_key = self.get_eckey_from_password(password)
if self.raw:
enc_magic = self._get_encryption_magic()
s = zlib.decompress(ec_key.decrypt_message(self.raw, enc_magic))
s = s.decode('utf8')
else:
s = ''
self.pubkey = ec_key.get_public_key_hex()
self.decrypted = s
def encrypt_before_writing(self, plaintext: str) -> str:
s = plaintext
if self.pubkey:
s = bytes(s, 'utf8')
c = zlib.compress(s, level=zlib.Z_BEST_SPEED)
enc_magic = self._get_encryption_magic()
public_key = ecc.ECPubkey(bfh(self.pubkey))
s = public_key.encrypt_message(c, enc_magic)
s = s.decode('utf8')
return s
def check_password(self, password) -> None:
"""Raises an InvalidPassword exception on invalid password"""
if not self.is_encrypted():
return
if not self.is_past_initial_decryption():
self.decrypt(password) # this sets self.pubkey
assert self.pubkey is not None
if self.pubkey != self.get_eckey_from_password(password).get_public_key_hex():
raise InvalidPassword()
def set_password(self, password, enc_version=None):
"""Set a password to be used for encrypting this storage."""
if not self.is_past_initial_decryption():
raise Exception("storage needs to be decrypted before changing password")
if enc_version is None:
enc_version = self._encryption_version
if password and enc_version != StorageEncryptionVersion.PLAINTEXT:
ec_key = self.get_eckey_from_password(password)
self.pubkey = ec_key.get_public_key_hex()
self._encryption_version = enc_version
else:
self.pubkey = None
self._encryption_version = StorageEncryptionVersion.PLAINTEXT
def basename(self) -> str:
return os.path.basename(self.path)