feat(core): Recognize Taproot inputs.

core/src/apps/bitcoin/common.py

@@ -20,6 +20,10 @@ SIGHASH_ALL = const(0x01)
 # The number of bip32 levels used in a wallet (chain and address)
 BIP32_WALLET_DEPTH = const(2)
 
+# Bitcoin opcodes
+OP_0 = const(0x00)
+OP_1 = const(0x51)
+
 # supported witness versions for bech32 addresses
 _BECH32_WITVERS = (0, 1)
 
@@ -48,6 +52,7 @@ CHANGE_OUTPUT_SCRIPT_TYPES = tuple(CHANGE_OUTPUT_TO_INPUT_SCRIPT_TYPES.keys())
 SEGWIT_INPUT_SCRIPT_TYPES = (
     InputScriptType.SPENDP2SHWITNESS,
     InputScriptType.SPENDWITNESS,
+    InputScriptType.SPENDTAPROOT,
 )
 
 SEGWIT_OUTPUT_SCRIPT_TYPES = (
@@ -101,10 +106,16 @@ def input_is_segwit(txi: TxInput) -> bool:
     )
 
 
-def input_is_nonsegwit(txi: TxInput) -> bool:
-    return txi.script_type in NONSEGWIT_INPUT_SCRIPT_TYPES or (
-        txi.script_type == InputScriptType.EXTERNAL and txi.witness is None
-    )
+def input_is_taproot(txi: TxInput) -> bool:
+    if txi.script_type == InputScriptType.SPENDTAPROOT:
+        return True
+
+    if txi.script_type == InputScriptType.EXTERNAL:
+        assert txi.script_pubkey is not None
+        if txi.script_pubkey[0] == OP_1:
+            return True
+
+    return False
 
 
 def input_is_external(txi: TxInput) -> bool:

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

@@ -223,7 +223,7 @@ class Bitcoin:
             if i in self.segwit:
                 if i in self.external:
                     txi = await helpers.request_tx_input(self.tx_req, i, self.coin)
-                    self.serialized_tx.extend(txi.witness or b"")
+                    self.serialized_tx.extend(txi.witness or b"\0")
                 else:
                     await self.sign_segwit_input(i)
             else:
@@ -455,7 +455,7 @@ class Bitcoin:
         # STAGE_REQUEST_SEGWIT_INPUT in legacy
         txi = await helpers.request_tx_input(self.tx_req, i, self.coin)
 
-        if not input_is_segwit(txi):
+        if txi.script_type not in common.SEGWIT_INPUT_SCRIPT_TYPES:
             raise wire.ProcessError("Transaction has changed during signing")
         self.tx_info.check_input(txi)
 
@@ -491,8 +491,7 @@ class Bitcoin:
     async def sign_segwit_input(self, i: int) -> None:
         # STAGE_REQUEST_SEGWIT_WITNESS in legacy
         txi = await helpers.request_tx_input(self.tx_req, i, self.coin)
-
-        if not input_is_segwit(txi):
+        if txi.script_type not in common.SEGWIT_INPUT_SCRIPT_TYPES:
             raise wire.ProcessError("Transaction has changed during signing")
 
         public_key, signature = self.sign_bip143_input(txi)

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

@@ -6,7 +6,7 @@ from trezor.messages import PrevTx, SignTx, TxInput
 from apps.common.writers import write_bitcoin_varint
 
 from .. import multisig, writers
-from ..common import input_is_nonsegwit
+from ..common import NONSEGWIT_INPUT_SCRIPT_TYPES
 from . import helpers
 from .bitcoin import Bitcoin
 
@@ -21,7 +21,7 @@ class Bitcoinlike(Bitcoin):
     async def sign_nonsegwit_bip143_input(self, i_sign: int) -> None:
         txi = await helpers.request_tx_input(self.tx_req, i_sign, self.coin)
 
-        if not input_is_nonsegwit(txi):
+        if txi.script_type not in NONSEGWIT_INPUT_SCRIPT_TYPES:
             raise wire.ProcessError("Transaction has changed during signing")
         public_key, signature = self.sign_bip143_input(txi)