signtx: add UI instructions, SigningError type

src/apps/common/signtx.py

@@ -20,6 +20,31 @@ from trezor.messages import OutputScriptType, InputScriptType
 # ===
 
 
+class SigningError(ValueError):
+    pass
+
+
+class UiConfirmOutput:
+
+    def __init__(self, output: TxOutputType):
+        self.output = output
+
+
+class UiConfirmTotal:
+
+    def __init__(self, total_out: int, fee: int):
+        self.total_out = total_out
+        self.fee = fee
+
+
+def confirm_output(output: TxOutputType):
+    yield UiConfirmOutput(output)
+
+
+def confirm_total(total_out: int, fee: int):
+    yield UiConfirmTotal(total_out, fee)
+
+
 def request_tx_meta(tx_req: TxRequest, tx_hash: bytes=None):
     tx_req.request_type = TXMETA
     tx_req.details.tx_hash = tx_hash
@@ -100,17 +125,16 @@ async def sign_tx(tx: SignTx, root):
         txo = await request_tx_output(tx_req, o)
         if output_is_change(txo):
             if change_out != 0:
-                raise ValueError('Only one change output is valid')
+                raise SigningError('Only one change output is valid')
             change_out = txo.amount
         txo_bin.amount = txo.amount
         txo_bin.script_pubkey = output_derive_script(txo, coin, root)
         write_tx_output(h_first, txo_bin)
         total_out += txo_bin.amount
-        # TODO: display output
+        await confirm_output(txo)
-        # TODO: confirm output
 
-    # TODO: check funds and tx fee
+    fee = total_in - total_out
-    # TODO: ask for confirmation
+    await confirm_total(total_out, fee)
 
     # Phase 2
     # - sign inputs
@@ -163,7 +187,7 @@ async def sign_tx(tx: SignTx, root):
 
         # check the control digests
         if tx_hash_digest(h_first, False) != tx_hash_digest(h_second, False):
-            raise ValueError('Transaction has changed during signing')
+            raise SigningError('Transaction has changed during signing')
 
         # compute the signature from the tx digest
         signature = ecdsa_sign(key_sign, tx_hash_digest(h_sign, True))
@@ -239,7 +263,7 @@ async def get_prevtx_output_value(tx_req: TxRequest, prev_hash: bytes, prev_inde
 
     prev_hash_rev = bytes(reversed(prev_hash))  # TODO: improve performance
     if tx_hash_digest(txh, True) != prev_hash_rev:
-        raise ValueError('Encountered invalid prev_hash')
+        raise SigningError('Encountered invalid prev_hash')
 
     return total_out
 
@@ -260,7 +284,7 @@ def output_derive_script(o: TxOutputType, coin: CoinType, root) -> bytes:
         ra = output_paytoaddress_extract_raw_address(o, coin, root)
         return script_paytoaddress_new(ra[1:])
     else:
-        raise ValueError('Invalid output script type')
+        raise SigningError('Invalid output script type')
     return
 
 
@@ -275,9 +299,9 @@ def output_paytoaddress_extract_raw_address(o: TxOutputType, coin: CoinType, roo
     elif o_address:
         raw_address = base58.decode_check(o_address)
     else:
-        raise ValueError('Missing address')
+        raise SigningError('Missing address')
     if raw_address[0] != coin.address_type:
-        raise ValueError('Invalid address type')
+        raise SigningError('Invalid address type')
     return raw_address
 
 
@@ -295,7 +319,7 @@ def input_derive_script_pre_sign(i: TxInputType, pubkey: bytes) -> bytes:
     if i_script_type == InputScriptType.SPENDADDRESS:
         return script_paytoaddress_new(ecdsa_hash_pubkey(pubkey))
     else:
-        raise ValueError('Unknown input script type')
+        raise SigningError('Unknown input script type')
 
 
 def input_derive_script_post_sign(i: TxInputType, pubkey: bytes, signature: bytes) -> bytes:
@@ -303,7 +327,7 @@ def input_derive_script_post_sign(i: TxInputType, pubkey: bytes, signature: byte
     if i_script_type == InputScriptType.SPENDADDRESS:
         return script_spendaddress_new(pubkey, signature)
     else:
-        raise ValueError('Unknown input script type')
+        raise SigningError('Unknown input script type')
 
 
 def node_derive(root, address_n: list):

tests/test_apps_common.signtx.py

@@ -12,7 +12,7 @@ from trezor.messages.TransactionType import TransactionType
 from trezor.messages.RequestType import TXINPUT, TXOUTPUT, TXMETA, TXFINISHED
 from trezor.messages.TxRequestDetailsType import TxRequestDetailsType
 from trezor.messages.TxRequestSerializedType import TxRequestSerializedType
-from trezor.messages import OutputScriptType, InputScriptType
+from trezor.messages import OutputScriptType
 
 from apps.common import signtx
 
@@ -57,6 +57,10 @@ class TestSignTx(unittest.TestCase):
             TxAck(tx=TransactionType(bin_outputs=[pout1])),
             TxRequest(request_type=TXOUTPUT, details=TxRequestDetailsType(request_index=0, tx_hash=None), serialized=None),
             TxAck(tx=TransactionType(outputs=[out1])),
+            signtx.UiConfirmOutput(out1),
+            True,
+            signtx.UiConfirmTotal(380000, 10000),
+            True,
             # ButtonRequest(code=ButtonRequest_ConfirmOutput),
             # ButtonRequest(code=ButtonRequest_SignTx),
             TxRequest(request_type=TXINPUT, details=TxRequestDetailsType(request_index=0, tx_hash=None), serialized=None),
@@ -80,10 +84,18 @@ class TestSignTx(unittest.TestCase):
 
         signer = signtx.sign_tx(tx, root)
         for request, response in chunks(messages, 2):
-            self.assertEqual(signer.send(request), response)
+            self.assertEqualEx(signer.send(request), response)
         with self.assertRaises(StopIteration):
             signer.send(None)
 
+    def assertEqualEx(self, a, b):
+        # hack to avoid adding __eq__ to signtx.Ui* classes
+        if ((isinstance(a, signtx.UiConfirmOutput) and isinstance(b, signtx.UiConfirmOutput)) or
+                (isinstance(a, signtx.UiConfirmTotal) and isinstance(b, signtx.UiConfirmTotal))):
+            return self.assertEqual(a.__dict__, b.__dict__)
+        else:
+            return self.assertEqual(a, b)
+
 
 if __name__ == '__main__':
     unittest.main()