From 0620911e4670dc465faef83e108d6baf55b6bd7a Mon Sep 17 00:00:00 2001
From: Pavol Rusnak <pavol@rusnak.io>
Date: Sat, 15 Aug 2020 18:25:54 +0200
Subject: [PATCH] core: allow spending coins from Bitcoin paths if the coin ...

has implemented strong replay protection via SIGHASH_FORKID
---
 core/CHANGELOG.md                       |  2 ++
 core/src/apps/bitcoin/keychain.py       | 10 ++++++++
 core/tests/test_apps.wallet.keychain.py | 34 ++++++++++++++++++++++++-
 3 files changed, 45 insertions(+), 1 deletion(-)

diff --git a/core/CHANGELOG.md b/core/CHANGELOG.md
index 26f7966c6a..7276e63bc5 100644
--- a/core/CHANGELOG.md
+++ b/core/CHANGELOG.md
@@ -16,6 +16,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Print inverted question mark for non-printable characters.
 - Remove pre-fill bar from text rendering functions.  [#1173]
 - Display coin name when signing or verifying messages.  [#1159]
+- Allow spending coins from Bitcoin paths if the coin has implemented strong replay protection via `SIGHASH_FORKID`.  [#1188]
 
 ### Deprecated
 
@@ -269,3 +270,4 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 [#1159]: https://github.com/trezor/trezor-firmware/issues/1159
 [#1165]: https://github.com/trezor/trezor-firmware/pull/1165
 [#1173]: https://github.com/trezor/trezor-firmware/pull/1173
+[#1188]: https://github.com/trezor/trezor-firmware/issues/1188
diff --git a/core/src/apps/bitcoin/keychain.py b/core/src/apps/bitcoin/keychain.py
index 24501689c3..6ad87b0af0 100644
--- a/core/src/apps/bitcoin/keychain.py
+++ b/core/src/apps/bitcoin/keychain.py
@@ -56,6 +56,16 @@ def get_namespaces_for_coin(coin: coininfo.CoinInfo):
         # m/0x4741b11e/6/pointer
         namespaces.append([0x4741B11E])
 
+    # some wallets such as Electron-Cash (BCH) store coins on Bitcoin paths
+    # we can allow spending these coins from Bitcoin paths if the coin has
+    # implemented strong replay protection via SIGHASH_FORKID
+    if coin.fork_id is not None:
+        namespaces.append([44 | HARDENED, 0 | HARDENED])
+        namespaces.append([48 | HARDENED, 0 | HARDENED])
+        if coin.segwit:
+            namespaces.append([49 | HARDENED, 0 | HARDENED])
+            namespaces.append([84 | HARDENED, 0 | HARDENED])
+
     return namespaces
 
 
diff --git a/core/tests/test_apps.wallet.keychain.py b/core/tests/test_apps.wallet.keychain.py
index e5f020cc07..6808992b05 100644
--- a/core/tests/test_apps.wallet.keychain.py
+++ b/core/tests/test_apps.wallet.keychain.py
@@ -87,14 +87,46 @@ class TestAltcoinKeychains(unittest.TestCase):
         self.assertFalse(coin.segwit)
         valid_addresses = (
             [44 | HARDENED, 145 | HARDENED],
+            [44 | HARDENED, 0 | HARDENED],
             [45 | HARDENED, 123456],
             [48 | HARDENED, 145 | HARDENED],
+            [48 | HARDENED, 0 | HARDENED],
         )
         invalid_addresses = (
             [43 | HARDENED, 145 | HARDENED],
-            [44 | HARDENED, 0 | HARDENED],
+            [43 | HARDENED, 0 | HARDENED],
             [49 | HARDENED, 145 | HARDENED],
+            [49 | HARDENED, 0 | HARDENED],
             [84 | HARDENED, 145 | HARDENED],
+            [84 | HARDENED, 0 | HARDENED],
+        )
+
+        for addr in valid_addresses:
+            keychain.derive(addr)
+
+        for addr in invalid_addresses:
+            self.assertRaises(wire.DataError, keychain.derive, addr)
+
+    def test_litecoin(self):
+        keychain, coin = await_result(
+            get_keychain_for_coin(wire.DUMMY_CONTEXT, "Litecoin")
+        )
+        self.assertEqual(coin.coin_name, "Litecoin")
+
+        self.assertTrue(coin.segwit)
+        valid_addresses = (
+            [44 | HARDENED, 2 | HARDENED],
+            [45 | HARDENED, 123456],
+            [48 | HARDENED, 2 | HARDENED],
+            [49 | HARDENED, 2 | HARDENED],
+            [84 | HARDENED, 2 | HARDENED],
+        )
+        invalid_addresses = (
+            [43 | HARDENED, 2 | HARDENED],
+            [44 | HARDENED, 0 | HARDENED],
+            [48 | HARDENED, 0 | HARDENED],
+            [49 | HARDENED, 0 | HARDENED],
+            [84 | HARDENED, 0 | HARDENED],
         )
 
         for addr in valid_addresses: