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trezor-firmware/src/apps/common/storage.py

244 lines
6.7 KiB

from micropython import const
from ubinascii import hexlify
from trezor import config
from trezor.crypto import random
from apps.common import cache
HOMESCREEN_MAXSIZE = 16384
_STORAGE_VERSION = b"\x02"
_FALSE_BYTE = b"\x00"
_TRUE_BYTE = b"\x01"
_COUNTER_HEAD_LEN = 4
_COUNTER_TAIL_LEN = 8
# fmt: off
_APP = const(0x01) # app namespace
_DEVICE_ID = const(0x00) # bytes
_VERSION = const(0x01) # int
_MNEMONIC = const(0x02) # str
_LANGUAGE = const(0x03) # str
_LABEL = const(0x04) # str
_USE_PASSPHRASE = const(0x05) # bool (0x01 or empty)
_HOMESCREEN = const(0x06) # bytes
_NEEDS_BACKUP = const(0x07) # bool (0x01 or empty)
_FLAGS = const(0x08) # int
_U2F_COUNTER = const(0x09) # int
_PASSPHRASE_SOURCE = const(0x0A) # int
_UNFINISHED_BACKUP = const(0x0B) # bool (0x01 or empty)
_AUTOLOCK_DELAY_MS = const(0x0C) # int
_NO_BACKUP = const(0x0D) # bool (0x01 or empty)
# fmt: on
def _set_bool(app: int, key: int, value: bool, public: bool = False) -> None:
if value:
config.set(app, key, _TRUE_BYTE, public)
else:
config.set(app, key, _FALSE_BYTE, public)
def _get_bool(app: int, key: int, public: bool = False) -> bool:
return config.get(app, key, public) == _TRUE_BYTE
def _set_counter(app: int, key: int, count: int, public: bool = False) -> None:
if count is None:
config.delete(app, key, public)
return
value = count.to_bytes(_COUNTER_HEAD_LEN, "big")
if public:
value += _COUNTER_TAIL_LEN * b"\xff"
config.set(app, key, value, public)
def _next_counter(app: int, key: int, public: bool = False) -> int:
# If the counter value is public, then it is stored as a four byte integer in
# big endian byte order, called the "head", followed an eight byte "tail". The
# counter value is equal to the integer value of the head plus the number of
# zero bits in the tail. The counter value 0 is stored as 00000000FFFFFFFFFFFFFFFF.
# With each increment the tail is shifted to the right by one bit. Thus after
# three increments the stored value is 000000001FFFFFFFFFFFFFFF. Once all the
# bits in the tail are set to zero, the next counter value is stored as
# 00000021FFFFFFFFFFFFFFFF.
value = config.get(app, key, public)
if value is None:
_set_counter(app, key, 0, public)
return 0
head = value[:_COUNTER_HEAD_LEN]
tail = value[_COUNTER_HEAD_LEN:]
i = tail.rfind(b"\x00") + 1
count = int.from_bytes(head, "big") + 1 + 8 * i
if i == len(tail):
_set_counter(app, key, count, public)
return count
zero_count = 0
while (tail[i] << zero_count) < 128:
zero_count += 1
count += zero_count
tail = tail[:i] + bytes([tail[i] >> 1]) + tail[i + 1 :]
config.set(app, key, head + tail, public)
return count
def _new_device_id() -> str:
return hexlify(random.bytes(12)).decode().upper()
def get_device_id() -> str:
dev_id = config.get(_APP, _DEVICE_ID, True) # public
if not dev_id:
dev_id = _new_device_id().encode()
config.set(_APP, _DEVICE_ID, dev_id, True) # public
return dev_id.decode()
def is_initialized() -> bool:
return bool(config.get(_APP, _VERSION))
def get_label() -> str:
label = config.get(_APP, _LABEL, True) # public
if label is None:
return None
return label.decode()
def get_mnemonic() -> str:
mnemonic = config.get(_APP, _MNEMONIC)
if mnemonic is None:
return None
return mnemonic.decode()
def has_passphrase() -> bool:
return _get_bool(_APP, _USE_PASSPHRASE)
def get_homescreen() -> bytes:
return config.get(_APP, _HOMESCREEN, True) # public
def load_mnemonic(mnemonic: str, needs_backup: bool, no_backup: bool) -> None:
config.set(_APP, _MNEMONIC, mnemonic.encode())
config.set(_APP, _VERSION, _STORAGE_VERSION)
_set_bool(_APP, _NO_BACKUP, no_backup)
if not no_backup:
_set_bool(_APP, _NEEDS_BACKUP, needs_backup)
def needs_backup() -> bool:
return _get_bool(_APP, _NEEDS_BACKUP)
def set_backed_up() -> None:
config.set(_APP, _NEEDS_BACKUP, b"")
def unfinished_backup() -> bool:
return _get_bool(_APP, _UNFINISHED_BACKUP)
def set_unfinished_backup(state: bool) -> None:
_set_bool(_APP, _UNFINISHED_BACKUP, state)
def no_backup() -> bool:
return _get_bool(_APP, _NO_BACKUP)
def get_passphrase_source() -> int:
b = config.get(_APP, _PASSPHRASE_SOURCE)
if b == b"\x01":
return 1
elif b == b"\x02":
return 2
else:
return 0
def load_settings(
label: str = None,
use_passphrase: bool = None,
homescreen: bytes = None,
passphrase_source: int = None,
) -> None:
if label is not None:
config.set(_APP, _LABEL, label.encode(), True) # public
if use_passphrase is not None:
_set_bool(_APP, _USE_PASSPHRASE, use_passphrase)
if homescreen is not None:
if homescreen[:8] == b"TOIf\x90\x00\x90\x00":
if len(homescreen) <= HOMESCREEN_MAXSIZE:
config.set(_APP, _HOMESCREEN, homescreen, True) # public
else:
config.set(_APP, _HOMESCREEN, b"", True) # public
if passphrase_source is not None:
if passphrase_source in [0, 1, 2]:
config.set(_APP, _PASSPHRASE_SOURCE, bytes([passphrase_source]))
def get_flags() -> int:
b = config.get(_APP, _FLAGS)
if b is None:
return 0
else:
return int.from_bytes(b, "big")
def set_flags(flags: int) -> None:
b = config.get(_APP, _FLAGS)
if b is None:
b = 0
else:
b = int.from_bytes(b, "big")
flags = (flags | b) & 0xFFFFFFFF
if flags != b:
config.set(_APP, _FLAGS, flags.to_bytes(4, "big"))
def get_autolock_delay_ms() -> int:
b = config.get(_APP, _AUTOLOCK_DELAY_MS)
if b is None:
return 10 * 60 * 1000
else:
return int.from_bytes(b, "big")
def set_autolock_delay_ms(delay_ms: int) -> None:
if delay_ms < 60 * 1000:
delay_ms = 60 * 1000
config.set(_APP, _AUTOLOCK_DELAY_MS, delay_ms.to_bytes(4, "big"))
def next_u2f_counter() -> int:
return _next_counter(_APP, _U2F_COUNTER, True) # public
def set_u2f_counter(cntr: int) -> None:
_set_counter(_APP, _U2F_COUNTER, cntr, True) # public
def wipe():
config.wipe()
cache.clear()
def init_unlocked():
# Check for storage version upgrade.
version = config.get(_APP, _VERSION)
if version == b"\x01":
# Make the U2F counter public.
counter = config.get(_APP, _U2F_COUNTER)
if counter is not None:
_set_counter(_APP, _U2F_COUNTER, counter, True) # public
config.delete(_APP, _U2F_COUNTER)
config.set(_APP, _VERSION, _STORAGE_VERSION)