From 208283e13e9c43a72240656a40733ff96a1d187c Mon Sep 17 00:00:00 2001
From: Andrew Kozlik <andrew.kozlik@gmail.com>
Date: Mon, 29 Jun 2020 18:12:21 +0200
Subject: [PATCH] core/bitcoin: Implement AuthorizeCoinJoin message.

---
 core/src/apps/bitcoin/__init__.py           |  1 +
 core/src/apps/bitcoin/authorize_coinjoin.py | 78 +++++++++++++++++++++
 2 files changed, 79 insertions(+)
 create mode 100644 core/src/apps/bitcoin/authorize_coinjoin.py

diff --git a/core/src/apps/bitcoin/__init__.py b/core/src/apps/bitcoin/__init__.py
index 47154d5466..b553702525 100644
--- a/core/src/apps/bitcoin/__init__.py
+++ b/core/src/apps/bitcoin/__init__.py
@@ -3,6 +3,7 @@ from trezor.messages import MessageType
 
 
 def boot() -> None:
+    wire.add(MessageType.AuthorizeCoinJoin, __name__, "authorize_coinjoin")
     wire.add(MessageType.GetPublicKey, __name__, "get_public_key")
     wire.add(MessageType.GetAddress, __name__, "get_address")
     wire.add(MessageType.GetOwnershipId, __name__, "get_ownership_id")
diff --git a/core/src/apps/bitcoin/authorize_coinjoin.py b/core/src/apps/bitcoin/authorize_coinjoin.py
new file mode 100644
index 0000000000..70f44dd235
--- /dev/null
+++ b/core/src/apps/bitcoin/authorize_coinjoin.py
@@ -0,0 +1,78 @@
+from micropython import const
+
+from trezor import ui
+from trezor.messages.AuthorizeCoinJoin import AuthorizeCoinJoin
+from trezor.messages.Success import Success
+from trezor.strings import format_amount
+from trezor.ui.text import Text
+
+from apps.base import set_authorization
+from apps.common.confirm import require_confirm, require_hold_to_confirm
+from apps.common.paths import validate_path
+
+from . import addresses
+from .authorization import FEE_PER_ANONYMITY_DECIMALS, CoinJoinAuthorization
+from .common import BIP32_WALLET_DEPTH
+from .keychain import get_keychain_for_coin
+
+if False:
+    from trezor import wire
+
+_MAX_COORDINATOR_LEN = const(18)
+
+
+async def authorize_coinjoin(ctx: wire.Context, msg: AuthorizeCoinJoin,) -> Success:
+    # We cannot use the @with_keychain decorator here, because we need the keychain
+    # to survive the function exit. The ownership of the keychain is transferred to
+    # the CoinJoinAuthorization object, which takes care of its destruction.
+    keychain, coin = await get_keychain_for_coin(ctx, msg.coin_name)
+
+    try:
+        if len(msg.coordinator) > _MAX_COORDINATOR_LEN or not all(
+            32 <= ord(x) <= 126 for x in msg.coordinator
+        ):
+            raise wire.DataError("Invalid coordinator name.")
+
+        if not msg.address_n:
+            raise wire.DataError("Empty path not allowed.")
+
+        await validate_path(
+            ctx,
+            addresses.validate_full_path,
+            keychain,
+            msg.address_n + [0] * BIP32_WALLET_DEPTH,
+            coin.curve_name,
+            coin=coin,
+            script_type=msg.script_type,
+        )
+
+        text = Text("Authorize CoinJoin", ui.ICON_RECOVERY)
+        text.normal("Do you really want to")
+        text.normal("take part in a CoinJoin")
+        text.normal("transaction at:")
+        text.mono(msg.coordinator)
+        await require_confirm(ctx, text)
+
+        text = Text("Authorize CoinJoin", ui.ICON_RECOVERY)
+        if msg.fee_per_anonymity is not None:
+            text.normal("Fee per anonymity set:")
+            text.bold(
+                "{} %".format(
+                    format_amount(msg.fee_per_anonymity, FEE_PER_ANONYMITY_DECIMALS)
+                )
+            )
+        text.normal("Maximum total fees:")
+        text.bold(
+            "{} {}".format(
+                format_amount(msg.max_total_fee, coin.decimals), coin.coin_shortcut
+            )
+        )
+        await require_hold_to_confirm(ctx, text)
+
+        set_authorization(CoinJoinAuthorization(msg, keychain, coin))
+
+    except BaseException:
+        keychain.__del__()
+        raise
+
+    return Success(message="CoinJoin authorized")