fix: properly return Failure.ActionCancelled in Pairing flow, add tests

core/src/apps/thp/pairing.py

@@ -27,7 +27,7 @@ from trezor.messages import (
 )
 from trezor.wire import message_handler
 from trezor.wire.context import UnexpectedMessageException
-from trezor.wire.errors import SilentError, UnexpectedMessage
+from trezor.wire.errors import ActionCancelled, SilentError, UnexpectedMessage
 from trezor.wire.thp import ChannelState, ThpError, crypto, get_enabled_pairing_methods
 from trezor.wire.thp.pairing_context import PairingContext
 
@@ -90,6 +90,9 @@ async def handle_pairing_request(
     ctx: PairingContext, message: protobuf.MessageType
 ) -> ThpEndResponse:
 
+    if Cancel.is_type_of(message):
+        raise ActionCancelled()
+
     if not ThpPairingRequest.is_type_of(message):
         raise UnexpectedMessage("Unexpected message")
 

tests/device_tests/thp/test_pairing.py

@@ -1,4 +1,5 @@
 import os
+import time
 import typing as t
 from hashlib import sha256
 
@@ -12,6 +13,9 @@ from trezorlib.debuglink import TrezorClientDebugLink as Client
 from trezorlib.messages import (
     ButtonAck,
     ButtonRequest,
+    Cancel,
+    Failure,
+    FailureType,
     ThpCodeEntryChallenge,
     ThpCodeEntryCommitment,
     ThpCodeEntryCpaceHostTag,
@@ -25,6 +29,7 @@ from trezorlib.messages import (
     ThpNfcTagTrezor,
     ThpPairingMethod,
     ThpPairingPreparationsFinished,
+    ThpPairingRequest,
     ThpQrCodeSecret,
     ThpQrCodeTag,
     ThpSelectMethod,
@@ -32,6 +37,7 @@ from trezorlib.messages import (
 from trezorlib.transport.thp import curve25519
 from trezorlib.transport.thp.cpace import Cpace
 
+
 from .connect import (
     get_encrypted_transport_protocol,
     handle_pairing_request,
@@ -145,6 +151,34 @@ def test_pairing_code_entry(client: Client) -> None:
     protocol._has_valid_channel = True
 
 
+def test_pairing_cancel_1(client: Client) -> None:
+    protocol = prepare_protocol_for_pairing(client)
+
+    protocol._send_message(ThpPairingRequest(host_name="TestTrezor Cancel 1"))
+    button_req = protocol._read_message(ButtonRequest)
+    assert button_req.name == "thp_pairing_request"
+
+    protocol._send_message(ButtonAck())
+    time.sleep(1)
+    protocol._send_message(Cancel())
+
+    resp = protocol._read_message(Failure)
+    assert resp.code == FailureType.ActionCancelled
+
+
+def test_pairing_cancel_2(client: Client) -> None:
+    protocol = prepare_protocol_for_pairing(client)
+
+    protocol._send_message(ThpPairingRequest(host_name="TestTrezor Cancel 2"))
+    button_req = protocol._read_message(ButtonRequest)
+    assert button_req.name == "thp_pairing_request"
+
+    protocol._send_message(ButtonAck())
+    client.debug.press_no()
+    resp = protocol._read_message(Failure)
+    assert resp.code == FailureType.ActionCancelled
+
+
 def test_pairing_nfc(client: Client) -> None:
     protocol = prepare_protocol_for_pairing(client)