333 lines
11 KiB
Python
333 lines
11 KiB
Python
# (c) Copyright 2018 by Coinkite Inc. This file is part of Coldcard <coldcardwallet.com>
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# and is covered by GPLv3 license found in COPYING.
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#
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# pincodes.py - manage PIN code (which map to wallet seeds)
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#
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import ustruct, ckcc, tcc
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from ubinascii import hexlify as b2a_hex
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from callgate import enter_dfu
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# See ../stm32/bootloader/pins.h for source of these constants.
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#
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MAX_PIN_LEN = const(32)
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# how many bytes per secret (you don't have to use them all)
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AE_SECRET_LEN = const(72)
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# magic number for struct
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PA_MAGIC = const(0x2eaf6311)
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# For state_flags field: report only covers current wallet (primary vs. secondary)
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PA_SUCCESSFUL = const(0x01)
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PA_IS_BLANK = const(0x02)
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PA_HAS_DURESS = const(0x04)
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PA_HAS_BRICKME = const(0x08)
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PA_ZERO_SECRET = const(0x10)
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# For change_flags field:
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CHANGE_WALLET_PIN = const(0x01)
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CHANGE_DURESS_PIN = const(0x02)
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CHANGE_BRICKME_PIN = const(0x04)
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CHANGE_SECRET = const(0x08)
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CHANGE_DURESS_SECRET = const(0x10)
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CHANGE_SECONDARY_WALLET_PIN = const(0x20)
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# See below for other direction as well.
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PA_ERROR_CODES = {
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-100: "HMAC_FAIL",
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-101: "HMAC_REQUIRED",
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-102: "BAD_MAGIC",
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-103: "RANGE_ERR",
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-104: "BAD_REQUEST",
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-105: "I_AM_BRICK",
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-106: "AE_FAIL",
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-107: "MUST_WAIT",
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-108: "PIN_REQUIRED",
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-109: "WRONG_SUCCESS",
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-110: "OLD_ATTEMPT",
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-111: "AUTH_MISMATCH",
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-112: "AUTH_FAIL",
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-113: "OLD_AUTH_FAIL",
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-114: "PRIMARY_ONLY",
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}
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# just a few of the likely ones; non-programing errors
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EPIN_I_AM_BRICK = const(-105)
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EPIN_MUST_WAIT = const(-107)
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EPIN_PIN_REQUIRED = const(-108)
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EPIN_WRONG_SUCCESS = const(-109)
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EPIN_OLD_ATTEMPT = const(-110)
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EPIN_AUTH_MISMATCH = const(-111)
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EPIN_AUTH_FAIL = const(-112)
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EPIN_OLD_AUTH_FAIL = const(-113)
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# We are round-tripping this big structure, partially signed by bootloader.
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'''
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uint32_t magic_value; // = PA_MAGIC
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int is_secondary; // (bool) primary or secondary
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char pin[MAX_PIN_LEN]; // value being attempted
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int pin_len; // valid length of pin
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uint32_t delay_achieved; // so far, how much time wasted?
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uint32_t delay_required; // how much will be needed?
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uint32_t num_fails; // for UI: number of fails PINs
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uint32_t attempt_target; // counter number from chip
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uint32_t state_flags; // what things have been setup/enabled already
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uint32_t private_state; // some internal (encrypted) state
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uint8_t hmac[32]; // bootloader's hmac over above, or zeros
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// remaining fields are return values, or optional args;
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int change_flags; // bitmask of what to do
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char old_pin[MAX_PIN_LEN]; // (optional) old PIN value
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int old_pin_len; // (optional) valid length of old_pin, can be zero
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char new_pin[MAX_PIN_LEN]; // (optional) new PIN value
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int new_pin_len; // (optional) valid length of new_pin, can be zero
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uint8_t secret[72]; // secret to be changed OR return value
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// may grow from here in future versions.
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'''
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PIN_ATTEMPT_FMT = 'Ii32si6I32si32si32si72s'
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PIN_ATTEMPT_SIZE = const(248)
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class BootloaderError(RuntimeError):
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pass
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class PinAttempt:
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seconds_per_tick = 0.5
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def __init__(self):
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self.is_secondary = False
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self.pin = None
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self.secret = None
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self.is_empty = None
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self.delay_achieved = 0 # so far, how much time wasted?
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self.delay_required = 0 # how much will be needed?
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self.num_fails = 0 # for UI: number of fails PINs
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self.attempt_target = 0 # counter number from chip
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self.state_flags = 0 # useful readback
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self.private_state = 0 # opaque data, but preserve
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assert MAX_PIN_LEN == 32 # update FMT otherwise
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assert ustruct.calcsize(PIN_ATTEMPT_FMT) == PIN_ATTEMPT_SIZE, ustruct.calcsize(PIN_ATTEMPT_FMT)
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self.buf = bytearray(PIN_ATTEMPT_SIZE)
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# check for bricked system early
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import callgate
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if callgate.get_is_bricked():
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# die right away if it's not going to work
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callgate.enter_dfu(3)
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def __repr__(self):
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return '<PinAttempt: secondary=%d num_fails=%d delay=%d/%d state=0x%x>' % (
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self.is_secondary, self.num_fails,
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self.delay_achieved, self.delay_required, self.state_flags)
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def marshal(self, msg, is_duress=False, is_brickme=False, new_secret=None,
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new_pin=None, old_pin=None, get_duress_secret=False, is_secondary=False):
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# serialize our state, and maybe some arguments
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change_flags = 0
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if new_secret is not None:
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change_flags |= CHANGE_SECRET if not is_duress else CHANGE_DURESS_SECRET
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assert len(new_secret) == AE_SECRET_LEN
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else:
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new_secret = bytes(AE_SECRET_LEN)
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# NOTE: pins should be bytes here.
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if get_duress_secret:
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# special case for reading duress secret from main wallet
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change_flags |= CHANGE_DURESS_SECRET
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if new_pin is not None:
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if is_duress:
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change_flags |= CHANGE_DURESS_PIN
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elif is_brickme:
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change_flags |= CHANGE_BRICKME_PIN
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elif is_secondary:
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change_flags |= CHANGE_SECONDARY_WALLET_PIN
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else:
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change_flags |= CHANGE_WALLET_PIN
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assert not old_pin or old_pin == self.pin
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old_pin = self.pin
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assert len(new_pin) <= MAX_PIN_LEN
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assert old_pin != None
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assert len(old_pin) <= MAX_PIN_LEN
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else:
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new_pin = b''
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old_pin = old_pin or self.pin
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ustruct.pack_into(PIN_ATTEMPT_FMT, msg, 0,
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PA_MAGIC,
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(1 if self.is_secondary else 0),
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self.pin, len(self.pin),
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self.delay_achieved,
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self.delay_required,
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self.num_fails,
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self.attempt_target,
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self.state_flags,
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self.private_state,
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self.hmac,
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change_flags,
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old_pin, len(old_pin),
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new_pin, len(new_pin),
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new_secret)
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def unmarshal(self, msg):
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# unpack it and update our state, return other state
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x = ustruct.unpack_from(PIN_ATTEMPT_FMT, msg)
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(magic, was_secondary,
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self.pin, pin_len,
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self.delay_achieved,
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self.delay_required,
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self.num_fails,
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self.attempt_target,
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self.state_flags,
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self.private_state,
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self.hmac,
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change_flags,
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old_pin, old_pin_len,
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new_pin, new_pin_len,
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secret) = x
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assert magic == PA_MAGIC, magic
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self.pin = self.pin[0:pin_len]
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# not useful to readback values we sent and it never updates
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#new_pin = new_pin[0:new_pin_len]
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#old_pin = old_pin[0:old_pin_len]
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return secret
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def roundtrip(self, method_num, **kws):
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self.marshal(self.buf, **kws)
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#print("> tx: %s" % b2a_hex(buf))
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err = ckcc.gate(18, self.buf, method_num)
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#print("[%d] rx: %s" % (err, b2a_hex(self.buf)))
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if err <= -100:
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#print("[%d] req: %s" % (err, b2a_hex(self.buf)))
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if err == EPIN_I_AM_BRICK:
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# don't try to continue!
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enter_dfu(3)
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raise BootloaderError(PA_ERROR_CODES[err], err)
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elif err:
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raise RuntimeError(err)
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return self.unmarshal(self.buf)
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@staticmethod
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def prefix_words(pin_prefix):
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# take a prefix of the PIN and turn it into a few
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# bip39 words for anti-phishing protection
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assert 1 <= len(pin_prefix) <= MAX_PIN_LEN, len(pin_prefix)
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buf = bytearray(pin_prefix + b'\0'*MAX_PIN_LEN)
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err = ckcc.gate(16, buf, len(pin_prefix))
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if err:
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raise RuntimeError(err)
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# use just 22 bits of that
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bits = ustruct.unpack('I', buf[0:4])[0]
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w1 = (bits >> 11) & 0x7ff
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w2 = bits & 0x7ff
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return tcc.bip39.lookup_nth(w1), tcc.bip39.lookup_nth(w2)
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def is_delay_needed(self):
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return self.delay_achieved < self.delay_required
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def is_blank(self):
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# device has no PIN at this point
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return bool(self.state_flags & PA_IS_BLANK)
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def is_successful(self):
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# we've got a valid pin
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return bool(self.state_flags & PA_SUCCESSFUL)
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def is_secret_blank(self):
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assert self.state_flags & PA_SUCCESSFUL
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return bool(self.state_flags & PA_ZERO_SECRET)
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def has_duress_pin(self):
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return bool(self.state_flags & PA_HAS_DURESS)
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def has_brickme_pin(self):
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return bool(self.state_flags & PA_HAS_BRICKME)
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def reset(self):
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# start over, like when you commit a new seed
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return self.setup(self.pin, self.is_secondary)
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def setup(self, pin, secondary=False):
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self.is_secondary = secondary
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self.pin = pin
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self.hmac = bytes(32)
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_ = self.roundtrip(0)
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return self.state_flags
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def delay(self):
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self.roundtrip(1)
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def login(self):
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# test we have the PIN code right, and unlock access if so.
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chk = self.roundtrip(2)
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self.is_empty = (chk[0] == 0)
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# IMPORTANT: You will need to re-read settings since the key for that has changed
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return self.is_successful()
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def change(self, **kws):
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# change various values, stored in secure element
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self.roundtrip(3, **kws)
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# IMPORTANT:
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# - call new_main_secret() when main secret changes!
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# - is_secret_blank and is_successful may be wrong now, re-login to get again
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def fetch(self, duress_pin=None):
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if duress_pin is None:
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secret = self.roundtrip(4)
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else:
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secret = self.roundtrip(4, get_duress_secret=True, old_pin=duress_pin)
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return secret
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def greenlight_firmware(self):
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# hash all of flash and commit value to 508a
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self.roundtrip(5)
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ckcc.presume_green()
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def new_main_secret(self, raw_secret, chain=None):
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# Main secret has changed: reset the settings+their key,
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# and capture xfp/xpub
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from main import settings
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import stash
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# capture values we have already
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old_values = dict(settings.current)
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settings.set_key(raw_secret)
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settings.load()
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# merge in settings, including what chain to use, timeout, etc.
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settings.merge(old_values)
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# Recalculate xfp/xpub values (depends both on secret and chain)
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with stash.SensitiveValues(raw_secret) as sv:
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if chain is not None:
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sv.chain = chain
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sv.capture_xpub()
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# does not call settings.save() but caller should!
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# EOF
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