[add] Enable NFC for Flex & Stax + minor fixes

CHANGELOG.md

@@ -5,6 +5,14 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+
+## [0.12.0] 2024-??-??
+
+### Added
+
+- NFC always enabled on Stax & Flex OSes
+- Starting Speculos with the `--nfc` argument will funel all communications as NFC
+
 ## [0.11.0] 2024-11-12
 
 ### Added

speculos/mcu/nfc.py

@@ -2,11 +2,9 @@
 Forward NFC packets between the MCU and the SE
 """
 
-from abc import ABC, abstractmethod
-from construct import Int8ub, Int16ub, Int16ul, Struct
-import binascii
 import enum
 import logging
+from typing import List, Optional
 
 
 class SephNfcTag(enum.IntEnum):
@@ -18,42 +16,36 @@ class NFC:
     def __init__(self, _queue_event_packet):
         self._queue_event_packet = _queue_event_packet
         self.packets_to_send = []
-        self.MTU=140
+        self.MTU = 140
         self.rx_sequence = 0
         self.rx_size = 0
-        self.rx_data = []
-
+        self.rx_data: bytes = b''
         self.logger = logging.getLogger("nfc")
 
-
-    def handle_rapdu_chunk(self, data):
+    def handle_rapdu_chunk(self, data: bytes) -> Optional[List[bytes]]:
         """concatenate apdu chunks into full apdu"""
-
         # example of data
         # 0000050000002b3330000409312e302e302d72633104e600000008362e312e302d646508352e312e302d6465010001009000
 
         # only APDU packets are suported
         if data[2] != 0x05:
-            return None
+            return
 
         sequence = int.from_bytes(data[3:5], 'big')
-        if self.rx_sequence != sequence:
-            print(f"Unexpected sequence number:{sequence}")
-            return None
+        assert self.rx_sequence == sequence, f"Unexpected sequence number:{sequence}"
 
         if sequence == 0:
             self.rx_size = int.from_bytes(data[5:7], "big")
             self.rx_data = data[7:]
         else:
-            self.rx_data.append(data[5:])
+            self.rx_data += data[5:]
 
         if len(self.rx_data) == self.rx_size:
-            #prepare for next call
+            # prepare for next call
             self.rx_sequence = 0
             return self.rx_data
-
-        return None
-
+        else:
+            self.rx_sequence += 1
 
     def apdu(self, data):
         chunks: List[bytes] = []
@@ -65,11 +57,11 @@ def apdu(self, data):
             data = data[size:]
 
         for i, chunk in enumerate(chunks):
-            # ledger protocol header
+            # Ledger protocol header
             header = bytes([0x00, 0x00, 0x05]) # APDU
             header += i.to_bytes(2, "big")
             # first packet contains the size of full buffer
             if i == 0:
                 header += data_len.to_bytes(2, "big")
 
-            self._queue_event_packet(SephNfcTag.NFC_APDU_EVENT, header+chunk)
+            self._queue_event_packet(SephNfcTag.NFC_APDU_EVENT, header + chunk)

speculos/mcu/seproxyhal.py

@@ -459,7 +459,7 @@ def can_read(self, screen: DisplayNotifier):
 
         elif tag == SephTag.NFC_RAPDU:
             data = self.nfc.handle_rapdu_chunk(data)
-            if data:
+            if data is not None:
                 for c in self.apdu_callbacks:
                     c(data)
                 screen.display.forward_to_apdu_client(data)

src/bolos/os.c

@@ -9,6 +9,7 @@
 #define OS_SETTING_PLANEMODE_OLD 5
 #define OS_SETTING_PLANEMODE_NEW 6
 #define OS_SETTING_SOUND         9
+#define OS_SETTING_FEATURES      14
 
 #undef PATH_MAX
 #define PATH_MAX 1024
@@ -54,7 +55,7 @@ unsigned long sys_os_setting_get(unsigned int setting_id,
       return 1;
     }
     if (((hw_model == MODEL_STAX) || (hw_model == MODEL_FLEX)) &&
-        setting_id == OS_SETTING_SOUND) {
+        (setting_id == OS_SETTING_SOUND || setting_id == OS_SETTING_FEATURES)) {
       return 0xff;
     }
   }