Ethereum: Fix fee computation.

- Gas is always in ether, even when sending tokens.
- Fee is computed by multiplying gas limit with gas price.
- Parse numbers already in sign_tx.
- Made rlp.encode non-recursive (also fixes not passing include_length).

src/apps/ethereum/layout.py

@@ -24,10 +24,10 @@ async def require_confirm_tx(ctx, to, value, chain_id, token=None):
 async def require_confirm_fee(ctx, spending, gas_price, gas_limit, chain_id, token=None):
     content = Text('Confirm transaction', ui.ICON_SEND,
                    ui.BOLD, format_ethereum_amount(spending, token, chain_id),
-                   ui.NORMAL, 'Gas:',
+                   ui.NORMAL, 'Gas price:',
-                   ui.BOLD, format_ethereum_amount(gas_price, token, chain_id),
+                   ui.BOLD, format_ethereum_amount(gas_price, None, chain_id),
-                   ui.NORMAL, 'Limit:',
+                   ui.NORMAL, 'Maximum fee:',
-                   ui.BOLD, format_ethereum_amount(gas_limit, token, chain_id),
+                   ui.BOLD, format_ethereum_amount(gas_price * gas_limit, None, chain_id),
                    icon_color=ui.GREEN)
     await require_hold_to_confirm(ctx, content, ButtonRequestType.SignTx)
 
@@ -52,7 +52,6 @@ def split_address(address):
 
 
 def format_ethereum_amount(value, token, chain_id):
-    value = int.from_bytes(value, 'big')
     if token:
         suffix = token[2]
         decimals = token[3]

src/apps/ethereum/sign_tx.py

@@ -20,22 +20,22 @@ async def ethereum_sign_tx(ctx, msg):
 
     # detect ERC - 20 token
     token = None
+    recipient = msg.to
+    value = int.from_bytes(msg.value, 'big')
     if len(msg.to) == 20 and \
        len(msg.value) == 0 and \
        data_total == 68 and \
        len(msg.data_initial_chunk) == 68 and \
        msg.data_initial_chunk[:16] == b'\xa9\x05\x9c\xbb\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00':
         token = tokens.token_by_chain_address(msg.chain_id, msg.to)
+        recipient = msg.data_initial_chunk[16:36]
+        value = int.from_bytes(msg.data_initial_chunk[36:68], 'big')
 
-    if token is None:
+    await require_confirm_tx(ctx, recipient, value, msg.chain_id, token)
-        await require_confirm_tx(ctx, msg.to, msg.value, msg.chain_id)
-    else:
-        await require_confirm_tx(ctx, msg.data_initial_chunk[16:36],  msg.data_initial_chunk[36:68], msg.chain_id, token)
-
     if token is None and msg.data_length > 0:
         await require_confirm_data(ctx, msg.data_initial_chunk, data_total)
 
-    await require_confirm_fee(ctx, msg.value, msg.gas_price, msg.gas_limit, msg.chain_id, token)
+    await require_confirm_fee(ctx, value, int.from_bytes(msg.gas_price, 'big'), int.from_bytes(msg.gas_limit, 'big'), msg.chain_id, token)
 
     data = bytearray()
     data += msg.data_initial_chunk

src/trezor/crypto/rlp.py

@@ -22,7 +22,7 @@ def encode_length(l: int, is_list: bool) -> bytes:
 
 def encode(data, include_length=True) -> bytes:
     if isinstance(data, int):
-        return encode(int_to_bytes(data))
+        data = int_to_bytes(data)
     if isinstance(data, bytearray):
         data = bytes(data)
     if isinstance(data, bytes):