You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 
 

374 lines
12 KiB

# SPDX-FileCopyrightText: 2020 Foundation Devices, Inc. <hello@foundationdevices.com>
# SPDX-License-Identifier: GPL-3.0-or-later
#
# SPDX-FileCopyrightText: 2018 Coinkite, Inc. <coldcardwallet.com>
# SPDX-License-Identifier: GPL-3.0-only
#
# (c) Copyright 2018 by Coinkite Inc. This file is part of Coldcard <coldcardwallet.com>
# and is covered by GPLv3 license found in COPYING.
#
# pincodes.py - manage PIN code (which map to wallet seeds)
#
import trezorcrypto
import ustruct
import version
from callgate import get_anti_phishing_words,get_supply_chain_validation_words
from ubinascii import hexlify as b2a_hex
from se_commands import *
from common import system
# See ../stm32/bootloader/pins.h for source of these constants.
#
MAX_PIN_LEN = const(32)
# how many bytes per secret (you don't have to use them all)
SE_SECRET_LEN = const(72)
# magic number for struct
PA_MAGIC_V1 = const(0xc50b61a7)
# For state_flags field: report only covers current wallet (primary vs. secondary)
PA_SUCCESSFUL = const(0x01)
PA_IS_BLANK = const(0x02)
PA_HAS_DURESS = const(0x04)
PA_HAS_BRICKME = const(0x08)
PA_ZERO_SECRET = const(0x10)
# For change_flags field:
CHANGE_WALLET_PIN = const(0x001)
CHANGE_DURESS_PIN = const(0x002)
CHANGE_BRICKME_PIN = const(0x004)
CHANGE_SECRET = const(0x008)
CHANGE_DURESS_SECRET = const(0x010)
# CHANGE_SECONDARY_WALLET_PIN = const(0x020)
CHANGE_LS_OFFSET = const(0xf00)
# See below for other direction as well.
PA_ERROR_CODES = {
-100: "HMAC_FAIL",
-101: "HMAC_REQUIRED",
-102: "BAD_MAGIC",
-103: "RANGE_ERR",
-104: "BAD_REQUEST",
-105: "I_AM_BRICK",
-106: "SE_FAIL",
-107: "MUST_WAIT",
-108: "PIN_REQUIRED",
-109: "WRONG_SUCCESS",
-110: "OLD_ATTEMPT",
-111: "AUTH_MISMATCH",
-112: "AUTH_FAIL",
-113: "OLD_AUTH_FAIL",
-114: "PRIMARY_ONLY",
}
# just a few of the likely ones; non-programing errors
EPIN_I_AM_BRICK = const(-105)
EPIN_MUST_WAIT = const(-107)
EPIN_PIN_REQUIRED = const(-108)
EPIN_WRONG_SUCCESS = const(-109)
EPIN_OLD_ATTEMPT = const(-110)
EPIN_AUTH_FAIL = const(-112)
EPIN_OLD_AUTH_FAIL = const(-113)
# We are round-tripping this big structure, partially signed by bootloader.
'''
uint32_t magic_value; // = PA_MAGIC_V1
char pin[MAX_PIN_LEN]; // value being attempted
int pin_len; // valid length of pin
uint32_t delay_achieved; // so far, how much time wasted? [508a only]
uint32_t delay_required; // how much will be needed? [508a only]
uint32_t num_fails; // for UI: number of fails PINs
uint32_t attempts_left; // trys left until bricking [608a only]
uint32_t state_flags; // what things have been setup/enabled already
uint32_t private_state; // some internal (encrypted) state
uint8_t hmac[32]; // bootloader's hmac over above, or zeros
// remaining fields are return values, or optional args;
int change_flags; // bitmask of what to do
char old_pin[MAX_PIN_LEN]; // (optional) old PIN value
int old_pin_len; // (optional) valid length of old_pin, can be zero
char new_pin[MAX_PIN_LEN]; // (optional) new PIN value
int new_pin_len; // (optional) valid length of new_pin, can be zero
uint8_t secret[72]; // secret to be changed OR return value
uint8_t cached_main_pin[32]; // iff they provided right pin already (V2)
'''
PIN_ATTEMPT_FMT_V1 = 'I32si6I32si32si32si72s32s'
PIN_ATTEMPT_SIZE_V1 = const(276)
# small cache of pin-prefix to words, for 608a based systems
_word_cache = []
class BootloaderError(RuntimeError):
pass
class PinAttempt:
seconds_per_tick = 0.5
def __init__(self):
self.pin = None
self.secret = None
self.is_empty = None
self.magic_value = PA_MAGIC_V1
self.delay_achieved = 0 # so far, how much time wasted?
self.delay_required = 0 # how much will be needed?
self.num_fails = 0 # for UI: number of fails PINs
self.attempts_left = 0 # ignore in mk1/2 case, only valid for mk3
self.max_attempts = 21 # Numbger of attempts allowed
self.state_flags = 0 # useful readback
self.private_state = 0 # opaque data, but preserve
self.cached_main_pin = bytearray(32)
assert MAX_PIN_LEN == 32 # update FMT otherwise
assert ustruct.calcsize(PIN_ATTEMPT_FMT_V1) == PIN_ATTEMPT_SIZE_V1, \
ustruct.calcsize(PIN_ATTEMPT_FMT_V1)
self.buf = bytearray(PIN_ATTEMPT_SIZE_V1)
# check for bricked system early
import callgate
if callgate.get_is_bricked():
# die right away if it's not going to work
# print('I AM I BRICKED!!!')
pass
def __repr__(self):
return '<PinAttempt: num_fails={} delay={}/{} attempts_left={} state=0x{} hmac={}>'.format(
self.num_fails,
self.delay_achieved, self.delay_required, self.attempts_left, hex(self.state_flags),
b2a_hex(self.hmac))
def marshal(self, msg, new_secret=None, new_pin=None, old_pin=None, ls_offset=None):
# serialize our state, and maybe some arguments
change_flags = 0
if new_secret is not None:
change_flags |= CHANGE_SECRET
assert len(new_secret) in (32, SE_SECRET_LEN)
else:
new_secret = bytes(SE_SECRET_LEN)
# NOTE: pins should be bytes here.
if new_pin is not None:
change_flags |= CHANGE_WALLET_PIN
assert not old_pin or old_pin == self.pin
old_pin = self.pin
assert len(new_pin) <= MAX_PIN_LEN
assert old_pin != None
assert len(old_pin) <= MAX_PIN_LEN
else:
new_pin = b''
old_pin = old_pin if old_pin is not None else self.pin
if ls_offset is not None:
change_flags |= (ls_offset << 8) # see CHANGE_LS_OFFSET
# can't send the V2 extra stuff if the bootrom isn't expecting it
fields = [self.magic_value,
self.pin,
len(self.pin),
self.delay_achieved,
self.delay_required,
self.num_fails,
self.attempts_left,
self.state_flags,
self.private_state,
self.hmac,
change_flags,
old_pin,
len(old_pin),
new_pin,
len(new_pin),
new_secret,
self.cached_main_pin]
fmt = PIN_ATTEMPT_FMT_V1
ustruct.pack_into(fmt, msg, 0, *fields)
def unmarshal(self, msg):
# unpack it and update our state, return other state
x = ustruct.unpack_from(PIN_ATTEMPT_FMT_V1, msg)
(self.magic_value,
self.pin,
pin_len,
self.delay_achieved,
self.delay_required,
self.num_fails,
self.attempts_left,
self.state_flags,
self.private_state,
self.hmac,
change_flags,
old_pin,
old_pin_len,
new_pin,
new_pin_len,
secret,
self.cached_main_pin) = x
# NOTE: not useful to readback values we sent and it never updates
#new_pin = new_pin[0:new_pin_len]
#old_pin = old_pin[0:old_pin_len]
self.pin = self.pin[0:pin_len]
return secret
def pin_control(self, method_num, **kws):
self.marshal(self.buf, **kws)
# print("> tx: %s" % b2a_hex(self.buf))
err = system.dispatch(CMD_PIN_CONTROL, self.buf, method_num)
# print("[%d] rx: %s" % (err, b2a_hex(self.buf)))
if err <= -100:
#print("[%d] req: %s" % (err, b2a_hex(self.buf)))
if err == EPIN_I_AM_BRICK:
raise RuntimeError(err)
# Unpack the updated attempts_left and num_fails if the pin was wrong so the UI updates correctly
if err == EPIN_AUTH_FAIL:
self.unmarshal(self.buf)
# print('Unmarshalled: {}'.format(self.attempts_left))
# print('ERROR: {} ({})'.format(PA_ERROR_CODES[err], err))
raise BootloaderError(PA_ERROR_CODES[err], err)
elif err:
raise RuntimeError(err)
return self.unmarshal(self.buf)
@staticmethod
def anti_phishing_words(pin_prefix):
# Take a prefix of the PIN and turn it into two
# bip39 words for anti-phishing protection.
assert 1 <= len(pin_prefix) <= MAX_PIN_LEN, len(pin_prefix)
# global _word_cache
# for k, v in _word_cache:
# if pin_prefix == k:
# return v
padding = MAX_PIN_LEN - len(pin_prefix)
buf = bytearray(pin_prefix + b'\0'*padding)
err = get_anti_phishing_words(buf)
if err:
raise RuntimeError(err)
# Get a mnemonic from the 32 bytes in the buffer
s = trezorcrypto.bip39.from_data(buf)
rv = s.split()
return rv[0:2] # Only keep 2 words for anti-phishing prefix
@staticmethod
def supply_chain_validation_words(challenge_str):
# Take the validation string and turn it into 4
# bip39 words for supply chain tampering detection.
# print('challenge_str={}'.format(challenge_str))
buf = bytearray(challenge_str)
# This actually gets the HMAC bytes, not the words
err = get_supply_chain_validation_words(buf)
if err:
raise RuntimeError(err)
# print('hmac buf = {}'.format(buf))
# Get a mnemonic from the 32 bytes in the buffer
buf = buf[:32]
if len(buf) < 32:
padding = 32 - len(buf)
buf = buf + b'\0'*padding
s = trezorcrypto.bip39.from_data(buf)
rv = s.split()
# print('supply chain validation words = {}'.format(rv[0:4]))
return rv[0:4] # Only keep 4 words for supply chain validation
def is_delay_needed(self):
return self.delay_achieved < self.delay_required
def is_blank(self):
# device has no PIN at this point
return bool(self.state_flags & PA_IS_BLANK)
def is_successful(self):
# we've got a valid pin
# print('self.state_flags = {:04x}'.format(self.state_flags))
return bool(self.state_flags & PA_SUCCESSFUL)
def is_secret_blank(self):
# assert self.state_flags & PA_SUCCESSFUL
return bool(self.state_flags & PA_ZERO_SECRET)
def reset(self):
# start over, like when you commit a new seed
return self.setup(self.pin)
# Prepare the class for a PIN operation (first pin, login, change)
def setup(self, pin, secondary=False):
# print('Setting up SE hmac')
self.pin = pin
self.hmac = bytes(32)
_ = self.pin_control(PIN_SETUP)
return self.state_flags
def login(self):
# test we have the PIN code right, and unlock access if so.
chk = self.pin_control(PIN_ATTEMPT)
self.is_empty = (chk[0] == 0)
# IMPORTANT: You will need to re-read settings since the key for that has changed
ok = self.is_successful()
if ok:
# it's a bit sensitive, and no longer useful: wipe.
global _word_cache
_word_cache.clear()
return ok
def change(self, **kws):
# change various values, stored in secure element
self.pin_control(PIN_CHANGE, **kws)
# IMPORTANT:
# - call new_main_secret() when main secret changes!
# - is_secret_blank and is_successful may be wrong now, re-login to get again
def fetch(self):
secret = self.pin_control(PIN_GET_SECRET)
return secret
async def new_main_secret(self, raw_secret, chain=None):
from common import settings, flash_cache
import stash
# Recalculate xfp/xpub values (depends both on secret and chain)
with stash.SensitiveValues(raw_secret) as sv:
if chain is not None:
sv.chain = chain
sv.capture_xpub()
# We shouldn't need to save this anymore since we are dynamically managing xfp and xpub
# await settings.save()
# Set the key for the flash cache (cache was inaccessible prior to user logging in)
flash_cache.set_key(new_secret=raw_secret)
# Need to save out flash cache with the new secret or else we won't be able to read it back later
flash_cache.save()
# EOF