core/bitcoin: move write_bitcoin_varint to common writers

core/src/apps/bitcoin/scripts.py

@@ -16,11 +16,7 @@ from .multisig import (
     multisig_get_pubkeys,
     multisig_pubkey_index,
 )
-from .writers import (
+from .writers import write_bytes_fixed, write_bytes_unchecked, write_op_push
-    write_bytes_fixed,
-    write_bytes_unchecked,
-    write_op_push,
-)
 
 if False:
     from typing import List, Optional
@@ -248,7 +244,7 @@ def input_script_p2wsh_in_p2sh(script_hash: bytes) -> bytearray:
 
 def witness_p2wpkh(signature: bytes, pubkey: bytes, sighash: int) -> bytearray:
     w = empty_bytearray(1 + 5 + len(signature) + 1 + 5 + len(pubkey))
-    write_varint(w, 0x02)  # num of segwit items, in P2WPKH it's always 2
+    write_bitcoin_varint(w, 0x02)  # num of segwit items, in P2WPKH it's always 2
     append_signature(w, signature, sighash)
     append_pubkey(w, pubkey)
     return w
@@ -287,17 +283,17 @@ def witness_p2wsh(
 
     w = empty_bytearray(total_length)
 
-    write_varint(w, num_of_witness_items)
+    write_bitcoin_varint(w, num_of_witness_items)
     # Starts with OP_FALSE because of an old OP_CHECKMULTISIG bug, which
     # consumes one additional item on the stack:
     # https://bitcoin.org/en/developer-guide#standard-transactions
-    write_varint(w, 0)
+    write_bitcoin_varint(w, 0)
 
     for s in signatures:
         append_signature(w, s, sighash)  # size of the witness included
 
     # redeem script
-    write_varint(w, redeem_script_length)
+    write_bitcoin_varint(w, redeem_script_length)
     write_output_script_multisig(w, pubkeys, multisig.m)
 
     return w

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

@@ -139,7 +139,7 @@ class Bitcoin:
 
     async def step4_serialize_inputs(self) -> None:
         self.write_tx_header(self.serialized_tx, self.tx, bool(self.segwit))
-        writers.write_varint(self.serialized_tx, self.tx.inputs_count)
+        write_bitcoin_varint(self.serialized_tx, self.tx.inputs_count)
 
         for i in range(self.tx.inputs_count):
             progress.advance()
@@ -149,7 +149,7 @@ class Bitcoin:
                 await self.sign_nonsegwit_input(i)
 
     async def step5_serialize_outputs(self) -> None:
-        writers.write_varint(self.serialized_tx, self.tx.outputs_count)
+        write_bitcoin_varint(self.serialized_tx, self.tx.outputs_count)
         for i in range(self.tx.outputs_count):
             progress.advance()
             await self.serialize_output(i)
@@ -275,7 +275,7 @@ class Bitcoin:
         h_check = self.create_hash_writer()
 
         self.write_tx_header(h_sign, self.tx, witness_marker=False)
-        writers.write_varint(h_sign, self.tx.inputs_count)
+        write_bitcoin_varint(h_sign, self.tx.inputs_count)
 
         for i in range(self.tx.inputs_count):
             # STAGE_REQUEST_4_INPUT in legacy
@@ -307,7 +307,7 @@ class Bitcoin:
                 script_pubkey = bytes()
             self.write_tx_input(h_sign, txi, script_pubkey)
 
-        writers.write_varint(h_sign, self.tx.outputs_count)
+        write_bitcoin_varint(h_sign, self.tx.outputs_count)
 
         for i in range(self.tx.outputs_count):
             # STAGE_REQUEST_4_OUTPUT in legacy
@@ -353,14 +353,14 @@ class Bitcoin:
 
         # witnesses are not included in txid hash
         self.write_tx_header(txh, tx, witness_marker=False)
-        writers.write_varint(txh, tx.inputs_cnt)
+        write_bitcoin_varint(txh, tx.inputs_cnt)
 
         for i in range(tx.inputs_cnt):
             # STAGE_REQUEST_2_PREV_INPUT in legacy
             txi = await helpers.request_tx_input(self.tx_req, i, self.coin, prev_hash)
             self.write_tx_input(txh, txi, txi.script_sig)
 
-        writers.write_varint(txh, tx.outputs_cnt)
+        write_bitcoin_varint(txh, tx.outputs_cnt)
 
         for i in range(tx.outputs_cnt):
             # STAGE_REQUEST_2_PREV_OUTPUT in legacy
@@ -413,8 +413,8 @@ class Bitcoin:
     ) -> None:
         writers.write_uint32(w, tx.version)  # nVersion
         if witness_marker:
-            writers.write_varint(w, 0x00)  # segwit witness marker
+            write_bitcoin_varint(w, 0x00)  # segwit witness marker
-            writers.write_varint(w, 0x01)  # segwit witness flag
+            write_bitcoin_varint(w, 0x01)  # segwit witness flag
 
     def write_tx_footer(
         self, w: writers.Writer, tx: Union[SignTx, TransactionType]

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

@@ -6,6 +6,8 @@ from trezor.messages.SignTx import SignTx
 from trezor.messages.TransactionType import TransactionType
 from trezor.messages.TxInputType import TxInputType
 
+from apps.common.writers import write_bitcoin_varint
+
 from .. import multisig, writers
 from . import helpers
 from .bitcoin import Bitcoin, input_is_nonsegwit
@@ -74,8 +76,8 @@ class Bitcoinlike(Bitcoin):
         if self.coin.timestamp:
             writers.write_uint32(w, tx.timestamp)
         if witness_marker:
-            writers.write_varint(w, 0x00)  # segwit witness marker
+            write_bitcoin_varint(w, 0x00)  # segwit witness marker
-            writers.write_varint(w, 0x01)  # segwit witness flag
+            write_bitcoin_varint(w, 0x01)  # segwit witness flag
 
     async def write_prev_tx_footer(
         self, w: writers.Writer, tx: TransactionType, prev_hash: bytes

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

@@ -12,6 +12,7 @@ from trezor.messages.TxOutputType import TxOutputType
 from trezor.utils import HashWriter, ensure
 
 from apps.common import coininfo, seed
+from apps.common.writers import write_bitcoin_varint
 
 from .. import multisig, scripts, writers
 from ..common import ecdsa_hash_pubkey, ecdsa_sign
@@ -36,21 +37,21 @@ class Decred(Bitcoin):
         super().__init__(tx, keychain, coin)
 
         self.write_tx_header(self.serialized_tx, self.tx, witness_marker=True)
-        writers.write_varint(self.serialized_tx, self.tx.inputs_count)
+        write_bitcoin_varint(self.serialized_tx, self.tx.inputs_count)
 
     def init_hash143(self) -> None:
         self.h_prefix = self.create_hash_writer()
         writers.write_uint32(
             self.h_prefix, self.tx.version | DECRED_SERIALIZE_NO_WITNESS
         )
-        writers.write_varint(self.h_prefix, self.tx.inputs_count)
+        write_bitcoin_varint(self.h_prefix, self.tx.inputs_count)
 
     def create_hash_writer(self) -> HashWriter:
         return HashWriter(blake256())
 
     async def step2_confirm_outputs(self) -> None:
-        writers.write_varint(self.serialized_tx, self.tx.outputs_count)
+        write_bitcoin_varint(self.serialized_tx, self.tx.outputs_count)
-        writers.write_varint(self.h_prefix, self.tx.outputs_count)
+        write_bitcoin_varint(self.h_prefix, self.tx.outputs_count)
         await super().step2_confirm_outputs()
         self.write_tx_footer(self.serialized_tx, self.tx)
         self.write_tx_footer(self.h_prefix, self.tx)
@@ -68,7 +69,7 @@ class Decred(Bitcoin):
         self.write_tx_output(self.serialized_tx, txo, script_pubkey)
 
     async def step4_serialize_inputs(self) -> None:
-        writers.write_varint(self.serialized_tx, self.tx.inputs_count)
+        write_bitcoin_varint(self.serialized_tx, self.tx.inputs_count)
 
         prefix_hash = self.h_prefix.get_digest()
 
@@ -99,13 +100,13 @@ class Decred(Bitcoin):
             writers.write_uint32(
                 h_witness, self.tx.version | DECRED_SERIALIZE_WITNESS_SIGNING
             )
-            writers.write_varint(h_witness, self.tx.inputs_count)
+            write_bitcoin_varint(h_witness, self.tx.inputs_count)
 
             for ii in range(self.tx.inputs_count):
                 if ii == i_sign:
                     writers.write_bytes_prefixed(h_witness, prev_pkscript)
                 else:
-                    writers.write_varint(h_witness, 0)
+                    write_bitcoin_varint(h_witness, 0)
 
             witness_hash = writers.get_tx_hash(
                 h_witness, double=self.coin.sign_hash_double, reverse=False

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

@@ -11,6 +11,7 @@ from trezor.utils import HashWriter, ensure
 
 from apps.common.coininfo import CoinInfo
 from apps.common.seed import Keychain
+from apps.common.writers import write_bitcoin_varint
 
 from ..multisig import multisig_get_pubkeys
 from ..scripts import output_script_multisig, output_script_p2pkh
@@ -22,7 +23,6 @@ from ..writers import (
     write_bytes_reversed,
     write_uint32,
     write_uint64,
-    write_varint,
 )
 from . import helpers
 from .bitcoinlike import Bitcoinlike
@@ -53,13 +53,13 @@ class Overwintered(Bitcoinlike):
 
         if self.tx.version == 3:
             write_uint32(self.serialized_tx, self.tx.expiry)  # expiryHeight
-            write_varint(self.serialized_tx, 0)  # nJoinSplit
+            write_bitcoin_varint(self.serialized_tx, 0)  # nJoinSplit
         elif self.tx.version == 4:
             write_uint32(self.serialized_tx, self.tx.expiry)  # expiryHeight
             write_uint64(self.serialized_tx, 0)  # valueBalance
-            write_varint(self.serialized_tx, 0)  # nShieldedSpend
+            write_bitcoin_varint(self.serialized_tx, 0)  # nShieldedSpend
-            write_varint(self.serialized_tx, 0)  # nShieldedOutput
+            write_bitcoin_varint(self.serialized_tx, 0)  # nShieldedOutput
-            write_varint(self.serialized_tx, 0)  # nJoinSplit
+            write_bitcoin_varint(self.serialized_tx, 0)  # nJoinSplit
         else:
             raise wire.DataError("Unsupported version for overwintered transaction")
 

core/src/apps/bitcoin/writers.py

@@ -8,6 +8,7 @@ from trezor.utils import ensure
 
 from apps.common.writers import (  # noqa: F401
     empty_bytearray,
+    write_bitcoin_varint,
     write_bytes_fixed,
     write_bytes_reversed,
     write_bytes_unchecked,
@@ -30,7 +31,7 @@ TX_HASH_SIZE = const(32)
 
 
 def write_bytes_prefixed(w: Writer, b: bytes) -> None:
-    write_varint(w, len(b))
+    write_bitcoin_varint(w, len(b))
     write_bytes_unchecked(w, b)
 
 
@@ -100,22 +101,6 @@ def write_op_push(w: Writer, n: int) -> None:
         w.append((n >> 24) & 0xFF)
 
 
-def write_varint(w: Writer, n: int) -> None:
-    ensure(n >= 0 and n <= 0xFFFFFFFF)
-    if n < 253:
-        w.append(n & 0xFF)
-    elif n < 0x10000:
-        w.append(253)
-        w.append(n & 0xFF)
-        w.append((n >> 8) & 0xFF)
-    else:
-        w.append(254)
-        w.append(n & 0xFF)
-        w.append((n >> 8) & 0xFF)
-        w.append((n >> 16) & 0xFF)
-        w.append((n >> 24) & 0xFF)
-
-
 def get_tx_hash(w: HashWriter, double: bool = False, reverse: bool = False) -> bytes:
     d = w.get_digest()
     if double:

core/src/apps/common/signverify.py

@@ -4,9 +4,9 @@ from trezor import utils, wire
 from trezor.crypto.hashlib import blake256, sha256
 from trezor.ui.text import Text
 
-from apps.bitcoin.writers import write_varint
 from apps.common.confirm import require_confirm
 from apps.common.layout import split_address
+from apps.common.writers import write_bitcoin_varint
 
 if False:
     from typing import List
@@ -18,9 +18,9 @@ def message_digest(coin: CoinType, message: bytes) -> bytes:
         h = utils.HashWriter(blake256())
     else:
         h = utils.HashWriter(sha256())
-    write_varint(h, len(coin.signed_message_header))
+    write_bitcoin_varint(h, len(coin.signed_message_header))
     h.extend(coin.signed_message_header)
-    write_varint(h, len(message))
+    write_bitcoin_varint(h, len(message))
     h.extend(message)
     ret = h.get_digest()
     if coin.sign_hash_double:

core/src/apps/common/writers.py

@@ -93,3 +93,19 @@ def write_bytes_reversed(w: Writer, b: bytes, length: int) -> int:
     ensure(len(b) == length)
     w.extend(bytes(reversed(b)))
     return length
+
+
+def write_bitcoin_varint(w: Writer, n: int) -> None:
+    ensure(n >= 0 and n <= 0xFFFFFFFF)
+    if n < 253:
+        w.append(n & 0xFF)
+    elif n < 0x10000:
+        w.append(253)
+        w.append(n & 0xFF)
+        w.append((n >> 8) & 0xFF)
+    else:
+        w.append(254)
+        w.append(n & 0xFF)
+        w.append((n >> 8) & 0xFF)
+        w.append((n >> 16) & 0xFF)
+        w.append((n >> 24) & 0xFF)

core/src/apps/lisk/sign_message.py

@@ -3,10 +3,10 @@ from trezor.crypto.hashlib import sha256
 from trezor.messages.LiskMessageSignature import LiskMessageSignature
 from trezor.utils import HashWriter
 
-from apps.bitcoin.sign_tx.writers import write_varint
 from apps.common import paths
 from apps.common.seed import with_slip44_keychain
 from apps.common.signverify import require_confirm_sign_message
+from apps.common.writers import write_bitcoin_varint
 from apps.lisk import CURVE, SLIP44_ID
 from apps.lisk.helpers import validate_full_path
 
@@ -14,9 +14,9 @@ from apps.lisk.helpers import validate_full_path
 def message_digest(message):
     h = HashWriter(sha256())
     signed_message_header = "Lisk Signed Message:\n"
-    write_varint(h, len(signed_message_header))
+    write_bitcoin_varint(h, len(signed_message_header))
     h.extend(signed_message_header)
-    write_varint(h, len(message))
+    write_bitcoin_varint(h, len(message))
     h.extend(message)
     return sha256(h.get_digest()).digest()