feat(core): Support Electrum signatures in VerifyMessage.

core/.changelog.d/2100.added

@@ -0,0 +1 @@
+Support Electrum signatures in VerifyMessage.

core/src/apps/bitcoin/verify_message.py

@@ -1,14 +1,16 @@
 from typing import TYPE_CHECKING
 
-from trezor import wire
+from trezor import utils, wire
+from trezor.crypto import base58
 from trezor.crypto.curve import secp256k1
 from trezor.enums import InputScriptType
 from trezor.messages import Success
-from trezor.ui.layouts import confirm_signverify
+from trezor.ui.layouts import confirm_signverify, show_success
 
-from apps.common import coins
+from apps.common import address_type, coins
 from apps.common.signverify import decode_message, message_digest
 
+from . import common
 from .addresses import (
     address_p2wpkh,
     address_p2wpkh_in_p2sh,
@@ -18,9 +20,44 @@ from .addresses import (
 )
 
 if TYPE_CHECKING:
+    from apps.common.coininfo import CoinInfo
     from trezor.messages import VerifyMessage
 
 
+def address_to_script_type(address: str, coin: CoinInfo) -> InputScriptType:
+    # Determines the script type from a non-multisig address.
+
+    if coin.bech32_prefix and address.startswith(coin.bech32_prefix):
+        witver, _ = common.decode_bech32_address(coin.bech32_prefix, address)
+        if witver == 0:
+            return InputScriptType.SPENDWITNESS
+        elif witver == 1:
+            return InputScriptType.SPENDTAPROOT
+        else:
+            raise wire.DataError("Invalid address")
+
+    if (
+        not utils.BITCOIN_ONLY
+        and coin.cashaddr_prefix is not None
+        and address.startswith(coin.cashaddr_prefix + ":")
+    ):
+        return InputScriptType.SPENDADDRESS
+
+    try:
+        raw_address = base58.decode_check(address, coin.b58_hash)
+    except ValueError:
+        raise wire.DataError("Invalid address")
+
+    if address_type.check(coin.address_type, raw_address):
+        # p2pkh
+        return InputScriptType.SPENDADDRESS
+    elif address_type.check(coin.address_type_p2sh, raw_address):
+        # p2sh
+        return InputScriptType.SPENDP2SHWITNESS
+
+    raise wire.DataError("Invalid address")
+
+
 async def verify_message(ctx: wire.Context, msg: VerifyMessage) -> Success:
     message = msg.message
     address = msg.address
@@ -30,17 +67,16 @@ async def verify_message(ctx: wire.Context, msg: VerifyMessage) -> Success:
 
     digest = message_digest(coin, message)
 
+    script_type = address_to_script_type(address, coin)
     recid = signature[0]
     if 27 <= recid <= 34:
-        # p2pkh
-        script_type = InputScriptType.SPENDADDRESS
-    elif 35 <= recid <= 38:
+        # p2pkh or no script type provided
+        pass  # use the script type from the address
+    elif 35 <= recid <= 38 and script_type == InputScriptType.SPENDP2SHWITNESS:
         # segwit-in-p2sh
-        script_type = InputScriptType.SPENDP2SHWITNESS
         signature = bytes([signature[0] - 4]) + signature[1:]
-    elif 39 <= recid <= 42:
+    elif 39 <= recid <= 42 and script_type == InputScriptType.SPENDWITNESS:
         # native segwit
-        script_type = InputScriptType.SPENDWITNESS
         signature = bytes([signature[0] - 8]) + signature[1:]
     else:
         raise wire.ProcessError("Invalid signature")
@@ -52,7 +88,7 @@ async def verify_message(ctx: wire.Context, msg: VerifyMessage) -> Success:
 
     if script_type == InputScriptType.SPENDADDRESS:
         addr = address_pkh(pubkey, coin)
-        if coin.cashaddr_prefix is not None:
+        if not utils.BITCOIN_ONLY and coin.cashaddr_prefix is not None:
             addr = address_to_cashaddr(addr, coin)
     elif script_type == InputScriptType.SPENDP2SHWITNESS:
         addr = address_p2wpkh_in_p2sh(pubkey, coin)

tests/device_tests/bitcoin/test_verifymessage_segwit.py

@@ -56,6 +56,18 @@ def test_message_verify(client: Client):
     )
     assert res is True
 
+    # no script type
+    res = btc.verify_message(
+        client,
+        "Bitcoin",
+        "3L6TyTisPBmrDAj6RoKmDzNnj4eQi54gD2",
+        bytes.fromhex(
+            "1f744de4516fac5c140808015664516a32fead94de89775cec7e24dbc24fe133075ac09301c4cc8e197bea4b6481661d5b8e9bf19d8b7b8a382ecdb53c2ee0750d"
+        ),
+        "This is an example of a signed message.",
+    )
+    assert res is True
+
     # trezor pubkey - FAIL - wrong sig
     res = btc.verify_message(
         client,

tests/device_tests/bitcoin/test_verifymessage_segwit_native.py

@@ -56,6 +56,18 @@ def test_message_verify(client: Client):
     )
     assert res is True
 
+    # no script type
+    res = btc.verify_message(
+        client,
+        "Bitcoin",
+        "bc1qannfxke2tfd4l7vhepehpvt05y83v3qsf6nfkk",
+        bytes.fromhex(
+            "20b55d7600d9e9a7e2a49155ddf3cfdb8e796c207faab833010fa41fb7828889bc47cf62348a7aaa0923c0832a589fab541e8f12eb54fb711c90e2307f0f66b194"
+        ),
+        "This is an example of a signed message.",
+    )
+    assert res is True
+
     # trezor pubkey - FAIL - wrong sig
     res = btc.verify_message(
         client,