core/sign_tx: Move Bitcoin class to bitcoin.py.

core/src/apps/wallet/sign_tx/__init__.py

@@ -7,13 +7,14 @@ from trezor.messages.TxRequest import TxRequest
 from apps.common import coins, paths, seed
 from apps.wallet.sign_tx import (
     addresses,
+    bitcoin,
+    common,
     helpers,
     layout,
     multisig,
     progress,
     scripts,
     segwit_bip143,
-    signing,
 )
 
 if not utils.BITCOIN_ONLY:
@@ -27,13 +28,13 @@ async def sign_tx(ctx: wire.Context, msg: SignTx, keychain: seed.Keychain) -> Tx
     coin_name = msg.coin_name if msg.coin_name is not None else "Bitcoin"
     coin = coins.by_name(coin_name)
     if not utils.BITCOIN_ONLY and coin.decred:
-        coinsig = decred.Decred()  # type: signing.Bitcoin
+        coinsig = decred.Decred()  # type: bitcoin.Bitcoin
     elif not utils.BITCOIN_ONLY and coin.overwintered:
         coinsig = zcash.Overwintered()
     elif not utils.BITCOIN_ONLY and coin_name not in ("Bitcoin", "Regtest", "Testnet"):
         coinsig = bitcoinlike.Bitcoinlike()
     else:
-        coinsig = signing.Bitcoin()
+        coinsig = bitcoin.Bitcoin()
 
     signer = coinsig.signer(msg, keychain, coin)
 
@@ -42,7 +43,7 @@ async def sign_tx(ctx: wire.Context, msg: SignTx, keychain: seed.Keychain) -> Tx
         try:
             req = signer.send(res)
         except (
-            signing.SigningError,
+            common.SigningError,
             multisig.MultisigError,
             addresses.AddressError,
             scripts.ScriptsError,

core/src/apps/wallet/sign_tx/bitcoin.py

@@ -2,8 +2,7 @@ import gc
 from micropython import const
 
 from trezor import utils
-from trezor.crypto import base58, bip32, der
+from trezor.crypto import base58
-from trezor.crypto.curve import secp256k1
 from trezor.crypto.hashlib import sha256
 from trezor.messages import FailureType, InputScriptType, OutputScriptType
 from trezor.messages.SignTx import SignTx
@@ -26,13 +25,12 @@ from apps.wallet.sign_tx import (
     tx_weight,
     writers,
 )
+from apps.wallet.sign_tx.common import SigningError, ecdsa_sign
+from apps.wallet.sign_tx.matchcheck import MultisigFingerprintChecker, WalletPathChecker
 
 if False:
     from typing import Dict, Union
 
-# the number of bip32 levels used in a wallet (chain and address)
-_BIP32_WALLET_DEPTH = const(2)
-
 # the chain id used for change
 _BIP32_CHANGE_CHAIN = const(1)
 
@@ -44,79 +42,6 @@ _BIP32_MAX_LAST_ELEMENT = const(1000000)
 _MAX_SERIALIZED_CHUNK_SIZE = const(2048)
 
 
-class SigningError(ValueError):
-    pass
-
-
-class MatchChecker:
-    """
-    MatchCheckers are used to identify the change-output in a transaction. An output is a change-output
-    if it has certain matching attributes with all inputs.
-    1. When inputs are first processed, add_input() is called on each one to determine if they all match.
-    2. Outputs are tested using output_matches() to tell whether they are admissible as a change-output.
-    3. Before signing each input, check_input() is used to ensure that the attribute has not changed.
-    """
-    MISMATCH = object()
-    UNDEFINED = object()
-
-    def __init__(self) -> None:
-        self.attribute = self.UNDEFINED  # type: object
-        self.read_only = False  # Failsafe to ensure that add_input() is not accidentally called after output_matches().
-
-    def attribute_from_tx(self, txio: Union[TxInputType, TxOutputType]) -> object:
-        # Return the attribute from the txio, which is to be used for matching.
-        # If the txio is invalid for matching, then return an object which
-        # evaluates as a boolean False.
-        raise NotImplementedError
-
-    def add_input(self, txi: TxInputType) -> None:
-        ensure(not self.read_only)
-
-        if self.attribute is self.MISMATCH:
-            return  # There was a mismatch in previous inputs.
-
-        added_attribute = self.attribute_from_tx(txi)
-        if not added_attribute:
-            self.attribute = self.MISMATCH  # The added input is invalid for matching.
-        elif self.attribute is self.UNDEFINED:
-            self.attribute = added_attribute  # This is the first input.
-        elif self.attribute != added_attribute:
-            self.attribute = self.MISMATCH
-
-    def check_input(self, txi: TxInputType) -> None:
-        if self.attribute is self.MISMATCH:
-            return  # There was already a mismatch when adding inputs, ignore it now.
-
-        # All added inputs had a matching attribute, allowing a change-output.
-        # Ensure that this input still has the same attribute.
-        if self.attribute != self.attribute_from_tx(txi):
-            raise SigningError(
-                FailureType.ProcessError, "Transaction has changed during signing"
-            )
-
-    def output_matches(self, txo: TxOutputType) -> bool:
-        self.read_only = True
-
-        if self.attribute is self.MISMATCH:
-            return False
-
-        return self.attribute_from_tx(txo) == self.attribute
-
-
-class WalletPathChecker(MatchChecker):
-    def attribute_from_tx(self, txio: Union[TxInputType, TxOutputType]) -> object:
-        if not txio.address_n:
-            return None
-        return txio.address_n[:-_BIP32_WALLET_DEPTH]
-
-
-class MultisigFingerprintChecker(MatchChecker):
-    def attribute_from_tx(self, txio: Union[TxInputType, TxOutputType]) -> object:
-        if not txio.multisig:
-            return None
-        return multisig.multisig_fingerprint(txio.multisig)
-
-
 # Transaction signing
 # ===
 # see https://github.com/trezor/trezor-mcu/blob/master/firmware/signing.c#L84
@@ -189,10 +114,11 @@ class Bitcoin:
         # legacy inputs in Step 4.
         self.h_confirmed = self.create_hash_writer()  # not a real tx hash
 
-        self.init_hash143()
+        # BIP-0143 transaction hashing
+        self.hash143 = self.create_hash143()
 
-    def init_hash143(self) -> None:
+    def create_hash143(self) -> segwit_bip143.Bip143:
-        self.hash143 = segwit_bip143.Bip143()  # BIP-0143 transaction hashing
+        return segwit_bip143.Bip143()
 
     def create_hash_writer(self) -> utils.HashWriter:
         return utils.HashWriter(sha256())
@@ -275,8 +201,10 @@ class Bitcoin:
             await helpers.confirm_foreign_address(txi.address_n)
 
         if input_is_segwit(txi):
+            self.segwit[i] = True
             await self.process_segwit_input(i, txi)
         elif input_is_nonsegwit(txi):
+            self.segwit[i] = False
             await self.process_nonsegwit_input(i, txi)
         else:
             raise SigningError(FailureType.DataError, "Wrong input script type")
@@ -284,12 +212,10 @@ class Bitcoin:
     async def process_segwit_input(self, i: int, txi: TxInputType) -> None:
         if not txi.amount:
             raise SigningError(FailureType.DataError, "Segwit input without amount")
-        self.segwit[i] = True
         self.bip143_in += txi.amount
         self.total_in += txi.amount
 
     async def process_nonsegwit_input(self, i: int, txi: TxInputType) -> None:
-        self.segwit[i] = False
         self.total_in += await self.get_prevtx_output_value(
             txi.prev_hash, txi.prev_index
         )
@@ -384,6 +310,7 @@ class Bitcoin:
                 txi_sign = txi
                 self.wallet_path.check_input(txi_sign)
                 self.multisig_fingerprint.check_input(txi_sign)
+                # NOTE: wallet_path is checked in write_tx_input_check()
                 node = self.keychain.derive(txi.address_n, self.coin.curve_name)
                 key_sign_pub = node.public_key()
                 # for the signing process the script_sig is equal
@@ -644,9 +571,3 @@ def input_is_segwit(txi: TxInputType) -> bool:
 
 def input_is_nonsegwit(txi: TxInputType) -> bool:
     return txi.script_type in helpers.NONSEGWIT_INPUT_SCRIPT_TYPES
-
-
-def ecdsa_sign(node: bip32.HDNode, digest: bytes) -> bytes:
-    sig = secp256k1.sign(node.private_key(), digest)
-    sigder = der.encode_seq((sig[1:33], sig[33:65]))
-    return sigder

core/src/apps/wallet/sign_tx/bitcoinlike.py

@@ -8,18 +8,18 @@ from trezor.messages.TransactionType import TransactionType
 from trezor.messages.TxInputType import TxInputType
 from trezor.messages.TxOutputType import TxOutputType
 
-from apps.wallet.sign_tx import addresses, helpers, multisig, signing, writers
+from apps.wallet.sign_tx import addresses, helpers, multisig, writers
+from apps.wallet.sign_tx.bitcoin import Bitcoin
+from apps.wallet.sign_tx.common import SigningError, ecdsa_sign
 
 if False:
     from typing import Union
 
 
-class Bitcoinlike(signing.Bitcoin):
+class Bitcoinlike(Bitcoin):
     async def process_segwit_input(self, i: int, txi: TxInputType) -> None:
         if not self.coin.segwit:
-            raise signing.SigningError(
+            raise SigningError(FailureType.DataError, "Segwit not enabled on this coin")
-                FailureType.DataError, "Segwit not enabled on this coin"
-            )
         await super().process_segwit_input(i, txi)
 
     async def process_nonsegwit_input(self, i: int, txi: TxInputType) -> None:
@@ -30,9 +30,7 @@ class Bitcoinlike(signing.Bitcoin):
 
     async def process_bip143_input(self, i: int, txi: TxInputType) -> None:
         if not txi.amount:
-            raise signing.SigningError(
+            raise SigningError(FailureType.DataError, "Expected input with amount")
-                FailureType.DataError, "Expected input with amount"
-            )
         self.segwit[i] = False
         self.bip143_in += txi.amount
         self.total_in += txi.amount
@@ -54,7 +52,7 @@ class Bitcoinlike(signing.Bitcoin):
             or txi_sign.script_type == InputScriptType.SPENDMULTISIG
         )
         if not is_bip143 or txi_sign.amount > self.bip143_in:
-            raise signing.SigningError(
+            raise SigningError(
                 FailureType.ProcessError, "Transaction has changed during signing"
             )
         self.bip143_in -= txi_sign.amount
@@ -73,7 +71,7 @@ class Bitcoinlike(signing.Bitcoin):
         if txi_sign.multisig:
             multisig.multisig_pubkey_index(txi_sign.multisig, key_sign_pub)
 
-        signature = signing.ecdsa_sign(key_sign, self.hash143_hash)
+        signature = ecdsa_sign(key_sign, self.hash143_hash)
 
         # serialize input with correct signature
         gc.collect()
@@ -100,7 +98,7 @@ class Bitcoinlike(signing.Bitcoin):
             elif version == cashaddr.ADDRESS_TYPE_P2SH:
                 version = self.coin.address_type_p2sh
             else:
-                raise signing.SigningError("Unknown cashaddr address type")
+                raise SigningError("Unknown cashaddr address type")
             return bytes([version]) + data
         else:
             return super().get_raw_address(txo)

core/src/apps/wallet/sign_tx/common.py

@@ -0,0 +1,12 @@
+from trezor.crypto import bip32, der
+from trezor.crypto.curve import secp256k1
+
+
+class SigningError(ValueError):
+    pass
+
+
+def ecdsa_sign(node: bip32.HDNode, digest: bytes) -> bytes:
+    sig = secp256k1.sign(node.private_key(), digest)
+    sigder = der.encode_seq((sig[1:33], sig[33:65]))
+    return sigder

core/src/apps/wallet/sign_tx/decred.py

@@ -12,8 +12,9 @@ from trezor.utils import HashWriter, ensure
 
 from apps.common import coininfo, seed
 from apps.wallet.sign_tx import addresses, helpers, multisig, progress, scripts, writers
+from apps.wallet.sign_tx.bitcoin import Bitcoin
+from apps.wallet.sign_tx.common import SigningError, ecdsa_sign
 from apps.wallet.sign_tx.segwit_bip143 import Bip143
-from apps.wallet.sign_tx.signing import Bitcoin, SigningError, ecdsa_sign
 
 DECRED_SERIALIZE_FULL = const(0 << 16)
 DECRED_SERIALIZE_NO_WITNESS = const(1 << 16)
@@ -64,8 +65,8 @@ class Decred(Bitcoin):
         ensure(coin.decred)
         super().initialize(tx, keychain, coin)
 
-    def init_hash143(self) -> None:
+    def create_hash143(self) -> Bip143:
-        self.hash143 = DecredPrefixHasher(self.tx)  # pseudo BIP-0143 prefix hashing
+        return DecredPrefixHasher(self.tx)  # pseudo BIP-0143 prefix hashing
 
     def create_hash_writer(self) -> HashWriter:
         return HashWriter(blake256())

core/src/apps/wallet/sign_tx/helpers.py

@@ -16,7 +16,7 @@ from trezor.messages.TxOutputBinType import TxOutputBinType
 from trezor.messages.TxOutputType import TxOutputType
 from trezor.messages.TxRequest import TxRequest
 
-from .signing import SigningError
+from .common import SigningError
 from .writers import TX_HASH_SIZE
 
 from apps.common.coininfo import CoinInfo

core/src/apps/wallet/sign_tx/matchcheck.py

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

core/src/apps/wallet/sign_tx/zcash.py

@@ -11,10 +11,10 @@ from trezor.utils import HashWriter, ensure
 from apps.common.coininfo import CoinInfo
 from apps.common.seed import Keychain
 from apps.wallet.sign_tx.bitcoinlike import Bitcoinlike
+from apps.wallet.sign_tx.common import SigningError
 from apps.wallet.sign_tx.multisig import multisig_get_pubkeys
 from apps.wallet.sign_tx.scripts import output_script_multisig, output_script_p2pkh
 from apps.wallet.sign_tx.segwit_bip143 import Bip143
-from apps.wallet.sign_tx.signing import SigningError
 from apps.wallet.sign_tx.writers import (
     TX_HASH_SIZE,
     get_tx_hash,
@@ -33,10 +33,6 @@ if False:
 OVERWINTERED = const(0x80000000)
 
 
-class ZcashError(ValueError):
-    pass
-
-
 def derive_script_code(txi: TxInputType, pubkeyhash: bytes) -> bytearray:
 
     if txi.multisig:
@@ -49,7 +45,7 @@ def derive_script_code(txi: TxInputType, pubkeyhash: bytes) -> bytearray:
         return output_script_p2pkh(pubkeyhash)
 
     else:
-        raise ZcashError(
+        raise SigningError(
             FailureType.DataError, "Unknown input script type for zip143 script code"
         )
 
@@ -188,13 +184,13 @@ class Overwintered(Bitcoinlike):
         ensure(coin.overwintered)
         super().initialize(tx, keychain, coin)
 
-    def init_hash143(self) -> None:
+    def create_hash143(self) -> Bip143:
         if self.tx.version == 3:
             branch_id = self.tx.branch_id or 0x5BA81B19  # Overwinter
-            self.hash143 = Zip143(branch_id)  # ZIP-0143 transaction hashing
+            return Zip143(branch_id)  # ZIP-0143 transaction hashing
         elif self.tx.version == 4:
             branch_id = self.tx.branch_id or 0x76B809BB  # Sapling
-            self.hash143 = Zip243(branch_id)  # ZIP-0243 transaction hashing
+            return Zip243(branch_id)  # ZIP-0243 transaction hashing
         else:
             raise SigningError(
                 FailureType.DataError,