core: fix BIP39 backup

Refers to #550. Not marking fixed because we need more tests.

core/src/apps/management/reset_device/__init__.py

@@ -58,6 +58,17 @@ async def reset_device(ctx: wire.Context, msg: ResetDevice) -> Success:
     if perform_backup:
         perform_backup = await layout.confirm_backup(ctx)
 
+    # Check backup type, convert seed accordingly
+    if msg.backup_type == BackupType.Bip39:
+        # in BIP-39 we store mnemonic string instead of the secret
+        secret = bip39.from_data(secret).encode()
+    elif msg.backup_type not in (BackupType.Slip39_Basic, BackupType.Slip39_Advanced):
+        # Unknown backup type.
+        # This check might seem superfluous, because we are checking
+        # in `_validate_reset_device` already, however, this is critical part,
+        # so just to make sure.
+        raise RuntimeError
+
     # generate and display backup information for the master secret
     if perform_backup:
         await backup_seed(ctx, msg.backup_type, secret)
@@ -70,16 +81,6 @@ async def reset_device(ctx: wire.Context, msg: ResetDevice) -> Success:
     storage.device.load_settings(
         label=msg.label, use_passphrase=msg.passphrase_protection
     )
-    if msg.backup_type == BackupType.Bip39:
-        # in BIP-39 we store mnemonic string instead of the secret
-        secret = bip39.from_data(secret).encode()
-    elif msg.backup_type not in (BackupType.Slip39_Basic, BackupType.Slip39_Advanced):
-        # Unknown backup type.
-        # This check might seem superfluous, because we are checking
-        # in `_validate_reset_device` already, however, this is critical part,
-        # so just to make sure.
-        raise RuntimeError
-
     storage.device.store_mnemonic_secret(
         secret,  # for SLIP-39, this is the EMS
         msg.backup_type,
@@ -153,11 +154,6 @@ async def backup_slip39_advanced(
     await layout.slip39_advanced_show_and_confirm_shares(ctx, mnemonics)
 
 
-async def backup_bip39(ctx: wire.Context, secret: bytes) -> None:
-    mnemonic = bip39.from_data(secret)
-    await layout.bip39_show_and_confirm_mnemonic(ctx, mnemonic)
-
-
 def _validate_reset_device(msg: ResetDevice) -> None:
     msg.backup_type = msg.backup_type or _DEFAULT_BACKUP_TYPE
     if msg.backup_type not in (
@@ -200,4 +196,4 @@ async def backup_seed(
     elif backup_type == BackupType.Slip39_Advanced:
         await backup_slip39_advanced(ctx, mnemonic_secret)
     else:
-        await backup_bip39(ctx, mnemonic_secret)
+        await layout.bip39_show_and_confirm_mnemonic(ctx, mnemonic_secret.decode())

tests/device_tests/test_msg_backup_device.py

@@ -0,0 +1,56 @@
+# This file is part of the Trezor project.
+#
+# Copyright (C) 2012-2019 SatoshiLabs and contributors
+#
+# This library is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License version 3
+# as published by the Free Software Foundation.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the License along with this library.
+# If not, see <https://www.gnu.org/licenses/lgpl-3.0.html>.
+
+
+import pytest
+
+from trezorlib import device, messages
+from trezorlib.messages import ButtonRequestType as B
+
+from ..common import MNEMONIC12, read_and_confirm_mnemonic
+
+
+@pytest.mark.skip_t1  # TODO we want this for t1 too
+@pytest.mark.setup_client(mnemonic=MNEMONIC12)
+def test_backup(client):
+    assert client.features.needs_backup is True
+    mnemonic = None
+
+    def input_flow():
+        nonlocal mnemonic
+        yield  # Confirm Backup
+        client.debug.press_yes()
+        yield  # Mnemonic phrases
+        mnemonic = read_and_confirm_mnemonic(client.debug, words=12)
+        yield  # Confirm success
+        client.debug.press_yes()
+        yield  # Backup is done
+        client.debug.press_yes()
+
+    with client:
+        client.set_input_flow(input_flow)
+        client.set_expected_responses(
+            [
+                messages.ButtonRequest(code=B.ResetDevice),
+                messages.ButtonRequest(code=B.ResetDevice),
+                messages.ButtonRequest(code=B.Success),
+                messages.ButtonRequest(code=B.Success),
+                messages.Success(),
+            ]
+        )
+        device.backup(client)
+
+    assert mnemonic == MNEMONIC12