test: reject unrenderable Ethereum amounts

Author: BitHighlander

tests/test_msg_ethereum_signtx.py

@@ -30,6 +30,49 @@
 
 
 class TestMsgEthereumSigntx(common.KeepKeyTest):
+    def test_ethereum_unrenderable_amounts_are_rejected(self):
+        """Neither a native nor ERC-20 amount may reach an approval blank."""
+        self.requires_firmware("7.14.2")
+        self.requires_fullFeature()
+        self.setup_mnemonic_nopin_nopassphrase()
+
+        recipient = binascii.unhexlify(
+            "1d1c328764a41bda0492b66baa30c4a339ff85ef"
+        )
+        max_uint256 = (1 << 256) - 1
+
+        with self.client:
+            self.client.set_expected_responses([
+                proto.Failure(
+                    code=proto_types.Failure_SyntaxError,
+                    message="Ethereum amount too large"),
+            ])
+            with self.assertRaises(CallException):
+                self.client.ethereum_sign_tx(
+                    n=[0, 0], nonce=0, gas_price=20, gas_limit=21000,
+                    to=recipient, value=max_uint256, chain_id=1,
+                )
+
+        # Known mainnet ERC-20 transfer with the same unrenderable amount.
+        erc20_data = (
+            binascii.unhexlify("a9059cbb" + "00" * 12) +
+            recipient + int_to_big_endian(max_uint256).rjust(32, b"\x00")
+        )
+        with self.client:
+            self.client.set_expected_responses([
+                proto.Failure(
+                    code=proto_types.Failure_SyntaxError,
+                    message="Ethereum amount too large"),
+            ])
+            with self.assertRaises(CallException):
+                self.client.ethereum_sign_tx(
+                    n=[0, 0], nonce=0, gas_price=20, gas_limit=60000,
+                    to=binascii.unhexlify(
+                        "d0d6d6c5fe4a677d343cc433536bb717bae167dd"
+                    ),
+                    value=0, chain_id=1, data=erc20_data,
+                )
+
     def test_ethereum_signtx_data(self):
         self.requires_fullFeature()
         self.setup_mnemonic_nopin_nopassphrase()