Andrew Kozlik
4 years ago
committed by
Andrew Kozlik
parent
a07e125793
commit
be7e98aa47
@ -0,0 +1,12 @@
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from trezor.crypto import bip32, der
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from trezor.crypto.curve import secp256k1
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class SigningError(ValueError):
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pass
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def ecdsa_sign(node: bip32.HDNode, digest: bytes) -> bytes:
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sig = secp256k1.sign(node.private_key(), digest)
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sigder = der.encode_seq((sig[1:33], sig[33:65]))
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return sigder
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@ -0,0 +1,85 @@
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from micropython import const
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from trezor.messages import FailureType
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from trezor.messages.TxInputType import TxInputType
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from trezor.messages.TxOutputType import TxOutputType
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from trezor.utils import ensure
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from apps.wallet.sign_tx import multisig
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from apps.wallet.sign_tx.common import SigningError
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if False:
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from typing import Union
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# the number of bip32 levels used in a wallet (chain and address)
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_BIP32_WALLET_DEPTH = const(2)
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class MatchChecker:
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"""
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MatchCheckers are used to identify the change-output in a transaction. An output is a change-output
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if it has certain matching attributes with all inputs.
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1. When inputs are first processed, add_input() is called on each one to determine if they all match.
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2. Outputs are tested using output_matches() to tell whether they are admissible as a change-output.
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3. Before signing each input, check_input() is used to ensure that the attribute has not changed.
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"""
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MISMATCH = object()
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UNDEFINED = object()
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def __init__(self) -> None:
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self.attribute = self.UNDEFINED # type: object
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self.read_only = False # Failsafe to ensure that add_input() is not accidentally called after output_matches().
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def attribute_from_tx(self, txio: Union[TxInputType, TxOutputType]) -> object:
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# Return the attribute from the txio, which is to be used for matching.
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# If the txio is invalid for matching, then return an object which
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# evaluates as a boolean False.
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raise NotImplementedError
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def add_input(self, txi: TxInputType) -> None:
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ensure(not self.read_only)
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if self.attribute is self.MISMATCH:
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return # There was a mismatch in previous inputs.
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added_attribute = self.attribute_from_tx(txi)
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if not added_attribute:
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self.attribute = self.MISMATCH # The added input is invalid for matching.
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elif self.attribute is self.UNDEFINED:
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self.attribute = added_attribute # This is the first input.
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elif self.attribute != added_attribute:
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self.attribute = self.MISMATCH
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def check_input(self, txi: TxInputType) -> None:
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if self.attribute is self.MISMATCH:
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return # There was already a mismatch when adding inputs, ignore it now.
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# All added inputs had a matching attribute, allowing a change-output.
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# Ensure that this input still has the same attribute.
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if self.attribute != self.attribute_from_tx(txi):
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raise SigningError(
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FailureType.ProcessError, "Transaction has changed during signing"
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)
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def output_matches(self, txo: TxOutputType) -> bool:
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self.read_only = True
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if self.attribute is self.MISMATCH:
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return False
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return self.attribute_from_tx(txo) == self.attribute
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class WalletPathChecker(MatchChecker):
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def attribute_from_tx(self, txio: Union[TxInputType, TxOutputType]) -> object:
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if not txio.address_n:
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return None
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return txio.address_n[:-_BIP32_WALLET_DEPTH]
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class MultisigFingerprintChecker(MatchChecker):
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def attribute_from_tx(self, txio: Union[TxInputType, TxOutputType]) -> object:
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if not txio.multisig:
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return None
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return multisig.multisig_fingerprint(txio.multisig)
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