bootloader: add OP_HARDWARE api endpoint

This will allow the bbapp to flash different FW versions, depending
on the PCB variants. The initial implementation will respond with a
single byte that identifies the Secure Chip: 0 for ATECC, 1 for Optiga.

Author: Beerosagos

CHANGELOG.md

@@ -151,9 +151,10 @@ customers cannot upgrade their bootloader, its changes are recorded separately.
 
 ## Bootloader
 
-### v1.0.7
+### v1.1.0
 - Update manufacturer HID descriptor to bitbox.swiss
 - Remove qtouch code from production bootloader
+- Implement OP_HARDWARE endpoint, to identify the secure chip model
 
 ### v1.0.6
 - Replace root pubkeys

CMakeLists.txt

@@ -93,7 +93,7 @@ endif()
 # Example 'v1.0.0'. They MUST not contain a pre-release label such as '-beta'.
 set(FIRMWARE_VERSION "v9.22.0")
 set(FIRMWARE_BTC_ONLY_VERSION "v9.22.0")
-set(BOOTLOADER_VERSION "v1.0.7")
+set(BOOTLOADER_VERSION "v1.1.0")
 
 find_package(PythonInterp 3.6 REQUIRED)
 

py/bitbox02/bitbox02/bitbox02/bootloader.py

@@ -18,9 +18,12 @@
 import io
 import math
 import hashlib
+import enum
+from typing import TypedDict
 
 from bitbox02.communication import TransportLayer
-from bitbox02.communication.devices import DeviceInfo
+
+from bitbox02.communication.devices import DeviceInfo, parse_device_version
 
 BOOTLOADER_CMD = 0x80 + 0x40 + 0x03
 NUM_ROOT_KEYS = 3
@@ -44,6 +47,19 @@
 SIGDATA_LEN = SIGNING_PUBKEYS_DATA_LEN + FIRMWARE_DATA_LEN
 
 
+class SecureChipModel(enum.Enum):
+    """Secure chip model variants for the BitBox02 platform."""
+
+    ATECC = "ATECC"
+    OPTIGA = "Optiga"
+
+
+class Hardware(TypedDict):
+    """Hardware configuration containing secure chip model information."""
+
+    secure_chip_model: SecureChipModel
+
+
 def parse_signed_firmware(firmware: bytes) -> typing.Tuple[bytes, bytes, bytes]:
     """
     Split raw firmware bytes into magic, sigdata and firmware
@@ -75,6 +91,10 @@ def __init__(self, transport: TransportLayer, device_info: DeviceInfo):
             "bb02btc-bootloader": SIGDATA_MAGIC_BTCONLY,
             "bitboxbase-bootloader": SIGDATA_MAGIC_BITBOXBASE_STANDARD,
         }.get(device_info["product_string"])
+        self.version = parse_device_version(device_info["serial_number"])
+        # Delete the prelease part, as it messes with the comparison (e.g. 3.0.0-pre < 3.0.0 is
+        # True, but the 3.0.0-pre has already the same API breaking changes like 3.0.0...).
+        self.version = self.version.replace(prerelease=None)
         assert self.expected_magic
 
     def _query(self, msg: bytes) -> bytes:
@@ -94,6 +114,25 @@ def versions(self) -> typing.Tuple[int, int]:
         firmware_v, signing_pubkeys_v = struct.unpack("<II", response[:8])
         return firmware_v, signing_pubkeys_v
 
+    def hardware(self) -> Hardware:
+        """
+        Returns (hardware variant).
+        """
+        secure_chip: SecureChipModel = SecureChipModel.ATECC
+
+        # Previous bootloader versions do not support the call and have ATECC SC.
+        if self.version >= "1.1.0":
+            response = self._query(b"W")
+            response_code = response[:1]
+
+            if response_code == b"\x00":
+                secure_chip = SecureChipModel.ATECC
+            elif response_code == b"\x01":
+                secure_chip = SecureChipModel.OPTIGA
+            else:
+                raise ValueError(f"Unrecognized securechip model: {response_code!r}")
+        return {"secure_chip_model": secure_chip}
+
     def get_hashes(
         self, display_firmware_hash: bool = False, display_signing_keydata_hash: bool = False
     ) -> typing.Tuple[bytes, bytes]:

py/bitbox02/bitbox02/communication/bitbox_api_protocol.py

@@ -557,9 +557,7 @@ def __init__(
 
         # Delete the prelease part, as it messes with the comparison (e.g. 3.0.0-pre < 3.0.0 is
         # True, but the 3.0.0-pre has already the same API breaking changes like 3.0.0...).
-        self.version = semver.VersionInfo(
-            self.version.major, self.version.minor, self.version.patch, build=self.version.build
-        )
+        self.version = self.version.replace(prerelease=None)
 
         # raises exceptions if the library is out of date
         self._check_max_version()

py/send_message.py

@@ -1482,6 +1482,11 @@ def _get_versions(self) -> None:
             version = self._device.versions()
             print(f"Firmware version: {version[0]}, Pubkeys version: {version[1]}")
 
+    def _get_hardware(self) -> None:
+        secure_chip = self._device.hardware()["secure_chip_model"]
+        print(f"Hardware variant:")
+        print(f"- Secure Chip: {secure_chip.value}")
+
     def _erase(self) -> None:
         self._device.erase()
 
@@ -1506,6 +1511,7 @@ def _menu(self) -> None:
         choices = (
             ("Boot", self._boot),
             ("Print versions", self._get_versions),
+            ("Print hardware variant", self._get_hardware),
             ("Erase firmware", self._erase),
             ("Show firmware hash at startup", self._show_fw_hash),
             ("Don't show firmware hash at startup", self._dont_show_fw_hash),

src/bootloader/bootloader.c

@@ -67,6 +67,8 @@
 #define OP_SCREEN_ROTATE ((uint8_t)'f') /* 0x66 */
 // OP_SET_SHOW_FIRMWARE_HASH - Enable or disable the flag to automatically show the firmware hash.
 #define OP_SET_SHOW_FIRMWARE_HASH ((uint8_t)'H') /* 0x4A */
+// OP_HARDWARE - Return the secure chip variant.
+#define OP_HARDWARE ((uint8_t)'W') /* 0x57 */
 
 // API return codes
 #define OP_STATUS_OK ((uint8_t)0)
@@ -766,6 +768,16 @@ static size_t _api_screen_rotate(uint8_t* output)
     return _report_status(OP_STATUS_OK, output);
 }
 
+static size_t _api_hardware(uint8_t* output)
+{
+    uint8_t type = 0;
+    if (memory_get_securechip_type() == MEMORY_SECURECHIP_TYPE_OPTIGA) {
+        type = 1;
+    }
+    output[BOOT_OP_LEN] = type;
+    return _report_status(OP_STATUS_OK, output) + 1;
+}
+
 static size_t _api_command(const uint8_t* input, uint8_t* output, const size_t max_out_len)
 {
     memset(output, 0, max_out_len);
@@ -809,6 +821,9 @@ static size_t _api_command(const uint8_t* input, uint8_t* output, const size_t m
     case OP_SCREEN_ROTATE:
         len = _api_screen_rotate(output);
         break;
+    case OP_HARDWARE:
+        len = _api_hardware(output);
+        break;
     default:
         len = _report_status(OP_STATUS_ERR_INVALID_CMD, output);
         _loading_ready = false;