fix(core): fix bugs in synchronization and handler finding

core/src/apps/base.py

@@ -367,7 +367,7 @@ def set_homescreen() -> None:
 def lock_device(interrupt_workflow: bool = True) -> None:
     if config.has_pin():
         config.lock()
-        wire.find_handler = get_pinlocked_handler
+        wire.message_handler.find_handler = get_pinlocked_handler
         set_homescreen()
         if interrupt_workflow:
             workflow.close_others()
@@ -403,7 +403,7 @@ async def unlock_device() -> None:
 
     _SCREENSAVER_IS_ON = False
     set_homescreen()
-    wire.find_handler = workflow_handlers.find_registered_handler
+    wire.message_handler.find_handler = workflow_handlers.find_registered_handler
 
 
 def get_pinlocked_handler(
@@ -462,6 +462,6 @@ def boot() -> None:
 
     reload_settings_from_storage()
     if config.is_unlocked():
-        wire.find_handler = workflow_handlers.find_registered_handler
+        wire.message_handler.find_handler = workflow_handlers.find_registered_handler
     else:
-        wire.find_handler = get_pinlocked_handler
+        wire.message_handler.find_handler = get_pinlocked_handler

core/src/trezor/wire/thp/ack_handler.py

@@ -1,4 +1,5 @@
 from storage.cache_thp import SessionThpCache
+from trezor import log
 
 from . import thp_session as THP
 
@@ -6,11 +7,17 @@ from . import thp_session as THP
 def handle_received_ACK(session: SessionThpCache, sync_bit: int) -> None:
 
     if _ack_is_not_expected(session):
+        if __debug__:
+            log.debug(__name__, "Received unexpected ACK message")
         return
     if _ack_has_incorrect_sync_bit(session, sync_bit):
+        if __debug__:
+            log.debug(__name__, "Received ACK message with wrong sync bit")
         return
 
     # ACK is expected and it has correct sync bit
+    if __debug__:
+        log.debug(__name__, "Received ACK message with correct sync bit")
     THP.sync_set_can_send_message(session, True)
 
 

core/src/trezor/wire/thp/thp_session.py

@@ -90,7 +90,8 @@ def sync_set_receive_expected_bit(session: SessionThpCache, bit: int) -> None:
 
     # set second bit to "bit" value
     session.sync &= 0xBF
-    session.sync |= 0x40
+    if bit:
+        session.sync |= 0x40
 
 
 def sync_set_send_bit_to_opposite(session: SessionThpCache) -> None:

core/src/trezor/wire/thp_v1.py

@@ -3,7 +3,7 @@ from micropython import const
 from typing import TYPE_CHECKING
 
 from storage.cache_thp import BROADCAST_CHANNEL_ID, SessionThpCache
-from trezor import io, loop, utils
+from trezor import io, log, loop, utils
 
 from .protocol_common import MessageWithId
 from .thp import ack_handler, checksum, thp_messages
@@ -101,6 +101,8 @@ async def read_message_or_init_packet(
         # the sole exception of cid_request which can be handled independently.
         if _is_ctrl_byte_continuation(ctrl_byte):
             # continuation packet is not expected - ignore
+            if __debug__:
+                log.debug(__name__, "Received unexpected continuation packet")
             report = None
             continue
         payload_length = ustruct.unpack(">H", report[3:])[0]
@@ -125,6 +127,8 @@ async def read_message_or_init_packet(
         if session_state == SessionState.UNALLOCATED:
             message = await _handle_unallocated(iface, cid)
             # unallocated should not return regular message, TODO, but it might change
+            if __debug__:
+                log.debug(__name__, "Channel with id: %d in UNALLOCATED", cid)
             if message is not None:
                 return message
             report = None
@@ -155,6 +159,13 @@ async def read_message_or_init_packet(
             continue
 
         # 3: Send ACK in response
+        if __debug__:
+            log.debug(
+                __name__,
+                "Writing ACK message to a channel with id: %d, sync bit: %d",
+                cid,
+                sync_bit,
+            )
         await _sendAck(iface, cid, sync_bit)
         THP.sync_set_receive_expected_bit(session, 1 - sync_bit)
 
@@ -257,6 +268,13 @@ async def write_message(
 
     header = InitHeader(ctrl_byte, cid, payload_length + CHECKSUM_LENGTH)
     chksum = checksum.compute(header.to_bytes() + payload)
+    if __debug__ and message.session_id is not None:
+        log.debug(
+            __name__,
+            "Writing message to a session with id: %d, message type: %d, ",
+            int.from_bytes(message.session_id, "big"),
+            message.type,
+        )
     await write_to_wire(iface, header, payload + chksum)
     # TODO set timeout for retransmission
 
@@ -299,6 +317,8 @@ async def _handle_broadcast(
     if ctrl_byte != _CHANNEL_ALLOCATION_REQ:
         raise ThpError("Unexpected ctrl_byte in broadcast channel packet")
 
+    if __debug__:
+        log.debug(__name__, "Received valid message on broadcast channel ")
     length, nonce = ustruct.unpack(">H8s", packet[3:])
     header = InitHeader(ctrl_byte, BROADCAST_CHANNEL_ID, length)
 
@@ -314,6 +334,8 @@ async def _handle_broadcast(
         len(response_data) + CHECKSUM_LENGTH,
     )
     chksum = checksum.compute(response_header.to_bytes() + response_data)
+    if __debug__:
+        log.debug(__name__, "New channel allocated with id %d", channel_id)
 
     await write_to_wire(iface, response_header, response_data + chksum)
 
@@ -328,6 +350,8 @@ async def _handle_allocated(
 
     # trim message type and checksum from payload
     message_data = payload[2:-CHECKSUM_LENGTH]
+    if __debug__:
+        log.debug(__name__, "Received valid message with type %d", message_type)
     return MessageWithId(message_type, message_data, session.session_id)
 
 
@@ -348,6 +372,8 @@ async def _sendAck(iface: WireInterface, cid: int, ack_bit: int) -> None:
 async def _handle_unexpected_sync_bit(
     iface: WireInterface, cid: int, sync_bit: int
 ) -> MessageWithId | None:
+    if __debug__:
+        log.debug(__name__, "Received message has unexpected synchronization bit")
     await _sendAck(iface, cid, sync_bit)
 
     # TODO handle cancelation messages and messages on allocated channels without synchronization