core/sign_tx: validate prevout amount in all cases

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

@@ -84,7 +84,6 @@ class Bitcoin:
 
         # amounts
         self.total_in = 0  # sum of input amounts
-        self.bip143_in = 0  # sum of segwit input amounts
         self.total_out = 0  # sum of output amounts
         self.change_out = 0  # change output amount
         self.weight = tx_weight.TxWeightCalculator(tx.inputs_count, tx.outputs_count)
@@ -178,26 +177,15 @@ class Bitcoin:
         if not addresses.validate_full_path(txi.address_n, self.coin, txi.script_type):
             await helpers.confirm_foreign_address(txi.address_n)
 
-        if input_is_segwit(txi):
-            await self.process_segwit_input(txi)
-        elif input_is_nonsegwit(txi):
-            await self.process_nonsegwit_input(txi)
-        else:
+        if txi.script_type not in helpers.INTERNAL_INPUT_SCRIPT_TYPES:
             raise wire.DataError("Wrong input script type")
 
-    async def process_segwit_input(self, txi: TxInputType) -> None:
-        await self.process_bip143_input(txi)
+        prev_amount = await self.get_prevtx_output_value(txi.prev_hash, txi.prev_index)
 
-    async def process_nonsegwit_input(self, txi: TxInputType) -> None:
-        self.total_in += await self.get_prevtx_output_value(
-            txi.prev_hash, txi.prev_index
-        )
+        if txi.amount is not None and prev_amount != txi.amount:
+            raise wire.DataError("Invalid amount specified")
 
-    async def process_bip143_input(self, txi: TxInputType) -> None:
-        if not txi.amount:
-            raise wire.DataError("Expected input with amount")
-        self.bip143_in += txi.amount
-        self.total_in += txi.amount
+        self.total_in += prev_amount
 
     async def confirm_output(self, txo: TxOutputType, script_pubkey: bytes) -> None:
         if self.change_out == 0 and self.output_is_change(txo):
@@ -229,13 +217,12 @@ class Bitcoin:
         self.write_tx_input(self.serialized_tx, txi, script_sig)
 
     def sign_bip143_input(self, txi: TxInputType) -> Tuple[bytes, bytes]:
+        if txi.amount is None:
+            raise wire.DataError("Expected input with amount")
+
         self.wallet_path.check_input(txi)
         self.multisig_fingerprint.check_input(txi)
 
-        if txi.amount > self.bip143_in:
-            raise wire.ProcessError("Transaction has changed during signing")
-        self.bip143_in -= txi.amount
-
         node = self.keychain.derive(txi.address_n)
         public_key = node.public_key()
         hash143_hash = self.hash143_preimage_hash(

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

@@ -4,7 +4,6 @@ from micropython import const
 from trezor import wire
 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
 
@@ -19,17 +18,6 @@ _SIGHASH_FORKID = const(0x40)
 
 
 class Bitcoinlike(Bitcoin):
-    async def process_segwit_input(self, txi: TxInputType) -> None:
-        if not self.coin.segwit:
-            raise wire.DataError("Segwit not enabled on this coin")
-        await super().process_segwit_input(txi)
-
-    async def process_nonsegwit_input(self, txi: TxInputType) -> None:
-        if self.coin.force_bip143:
-            await self.process_bip143_input(txi)
-        else:
-            await super().process_nonsegwit_input(txi)
-
     async def sign_nonsegwit_bip143_input(self, i_sign: int) -> None:
         txi = await helpers.request_tx_input(self.tx_req, i_sign, self.coin)
 
@@ -83,11 +71,11 @@ class Bitcoinlike(Bitcoin):
         await super().write_prev_tx_footer(w, tx, prev_hash)
 
         if self.coin.extra_data:
-            ofs = 0
-            while ofs < tx.extra_data_len:
-                size = min(1024, tx.extra_data_len - ofs)
+            offset = 0
+            while offset < tx.extra_data_len:
+                size = min(1024, tx.extra_data_len - offset)
                 data = await helpers.request_tx_extra_data(
-                    self.tx_req, ofs, size, prev_hash
+                    self.tx_req, offset, size, prev_hash
                 )
                 writers.write_bytes_unchecked(w, data)
-                ofs += len(data)
+                offset += len(data)

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

@@ -52,10 +52,8 @@ class Overwintered(Bitcoinlike):
         self.write_tx_footer(self.serialized_tx, self.tx)
 
         if self.tx.version == 3:
-            write_uint32(self.serialized_tx, self.tx.expiry)  # expiryHeight
             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_bitcoin_varint(self.serialized_tx, 0)  # nShieldedSpend
             write_bitcoin_varint(self.serialized_tx, 0)  # nShieldedOutput
@@ -65,9 +63,6 @@ class Overwintered(Bitcoinlike):
 
         await helpers.request_tx_finish(self.tx_req)
 
-    async def process_nonsegwit_input(self, txi: TxInputType) -> None:
-        await self.process_bip143_input(txi)
-
     async def sign_nonsegwit_input(self, i_sign: int) -> None:
         await self.sign_nonsegwit_bip143_input(i_sign)
 
@@ -78,6 +73,10 @@ class Overwintered(Bitcoinlike):
         write_uint32(w, tx.version | OVERWINTERED)
         write_uint32(w, tx.version_group_id)  # nVersionGroupId
 
+    def write_tx_footer(self, w: Writer, tx: Union[SignTx, TransactionType]) -> None:
+        write_uint32(w, tx.lock_time)
+        write_uint32(w, tx.expiry)  # expiryHeight
+
     # ZIP-0143 / ZIP-0243
     # ===
 

core/tests/test_apps.bitcoin.segwit.signtx.p2wpkh_in_p2sh.py

@@ -343,7 +343,7 @@ class TestSignSegwitTxP2WPKHInP2SH(unittest.TestCase):
         messages_count = int(len(messages) / 2)
         for request, response in chunks(messages, 2):
             if i == messages_count - 1:  # last message should throw wire.Error
-                self.assertRaises(wire.ProcessError, signer.send, request)
+                self.assertRaises(wire.DataError, signer.send, request)
             else:
                 self.assertEqual(signer.send(request), response)
             i += 1