class FotaSuit:
"""
Implementation of OTA with MQTT Broker according to the SUIT specification for IoT devices.
Args:
_uuid_project (string): universal unique id from project
(only used if not exists an local manifest).
_id_device (string): id from device inside project.
_version (integer): Current version of device
(only used if not exists an local manifest).
_host_broker (string): address from broker.
_callback_on_receive_update (function): called when upgrade file received.
_pubkey (string): public key from server.
_delivery_type (string, optional): update search strategy pass: '******' or 'Push'.
Default is 'Push'.
_debug (boolean, optional): enable debug from class. Default is True.
Returns:
object from class
"""
def __init__(self, _uuid_project, _id_device, _version, _host_broker, \
_callback_on_receive_update, _private_key=None, _public_key=None, _delivery_type='Push', _debug=True):
self.host_broker = _host_broker
self.debug = _debug
self.delivery_type = _delivery_type
self.id_device = _id_device
self.private_key = _private_key
self.public_key = _public_key
self.security = Security()
self.message_incoming = bytes()
self.do_decrypt = False
self.aes_random_key = ''
_id_on_broker = "FotaSuit-" + _uuid_project + "-" + self.id_device
self.mqtt_client = MQTTClient(_id_on_broker, self.host_broker)
self.mqtt_client.DEBUG = self.debug
self.mqtt_client.set_callback(self.publish_received)
self.update_file_size = 0
self.update_file_index = 0
self.update_file_handle = 0
self.memory = Memory(self.debug)
_next_partition = self.memory.get_next_partition_name()
self.callback_on_receive_update = _callback_on_receive_update
if not (self.delivery_type == 'Push' or self.delivery_type == 'Pull'):
raise ValueError("'type' variable not supported. Try 'Pull' or 'Push'.")
while not self.connect_on_broker(True):
self.print_debug("trying connection with broker...")
time.sleep(3)
self.manifest = Manifest(_next_partition, _public_key)
self.manifest.load(_uuid_project, _version)
files = os.listdir()
if '_updated.iota' in files: #have an update ?
# notify the upgrade
_version = str(self.manifest.version)
_msg = '{"idDevice":"'+self.id_device+'", "uuidProject":"'+_uuid_project+'"'
_msg += ', "version":'+_version+', "date": ""}'
#TODO: insert other informations in message like date
self.publish_on_topic(_version, "updated", _msg)
os.remove('_updated.iota')
self.subscribe_task = "manifest" # waiting for manifest file
self.print_debug("initialized.")
# _thread.start_new_thread(self.loop, ())
def connect_on_broker(self, _clean_session):
"""
try connection with MQTT broker.
Args:
_clean_session (boolean): clean session with broker.
Returns:
boolean indicating status of connection.
"""
try:
if not self.mqtt_client.connect(clean_session=_clean_session):
self.print_debug("connected on broker.")
return True
except:
self.print_debug("fail to connect with broker.")
return False
def get_name_topic(self, _topic):
return
def unsubscribe_from_topic(self, _topic):
"""
unsubscribe from iota topic: iota/<uuidProject>/<version>/_topic
Args:
_topic (string): topic name to unsubscribe.
Returns:
void.
"""
_next_version = str(self.manifest.get_next_version())
_topic = "iota/"+self.manifest.uuid_project+"/"+_next_version+"/"+_topic
self.mqtt_client.unsubscribe(_topic.encode())
self.print_debug("unsubscribed on topic: " + _topic)
def subscribe_on_topic(self, _topic):
"""
subscribe on iota topic: iota/<uuidProject>/<version>/_topic
Args:
_topic (string): topic name to subscribe.
Returns:
void.
"""
_next_version = str(self.manifest.get_next_version())
_topic = "iota/"+self.manifest.uuid_project+"/"+_next_version+"/"+_topic
self.mqtt_client.subscribe(_topic.encode())
self.print_debug("subscribed on topic: " + _topic)
def publish_on_topic(self, _version, _topic, _msg):
"""
publish on iota topic: iota/<uuidProject>/<idDevice>/<version>/_topic
Args:
_version (string): version to publish.
_topic (string): topic name to publish.
_msg (string): message to publish.
Returns:
void.
"""
_topic = "iota/"+self.manifest.uuid_project+"/"+self.id_device+"/"+_version+"/"+_topic
self.mqtt_client.publish(_topic.encode(), _msg.encode(), True) # retain this message!
self.print_debug("published on topic: " + _topic + " msg:" + _msg)
def verify_file(self):
"""
verifies the signature from upgrade file
Args:
void.
Returns:
boolean indicating the success of the signature verification.
"""
_file_data = self.security.sha256_ret()
if self.upgrade_is_secure():
_sign_str = self.manifest.new['files'][self.update_file_index]['sign']
try:
if self.security.ecdsa_secp256k1_verifiy_sign(self.public_key, _file_data, _sign_str):
return True
except Exception as error:
print(error)
return False
else:
return True
def upgrade_is_secure(self):
return 'key' in self.manifest.new
def publish_received(self, _topic, _message, _size_msg):
"""
publish received on iota topic: iota/<uuid>/<version>/_topic
Args:
_topic (bytes): topic name from received message.
_message (bytes): message received.
_size_msg (int): total message size
Returns:
void.
"""
_topic_str = _topic.decode("utf-8")
_topic_name = self.parse_topic(_topic_str)
if _topic_name == 'manifest':
self.message_incoming += _message
if len(self.message_incoming) == _size_msg:
_msg_str = self.message_incoming.decode("utf-8")
self.print_debug("topic received: " + _topic_str)
self.print_debug("msg received: " + _msg_str)
if self.manifest.save_new(_msg_str):
self.print_debug('new version avaliable.')
self.update_file_size = 0
self.update_file_index = 0
_name_new_file = self.manifest.new['files'][self.update_file_index]['name']
if self.manifest.new['type'] == 'py':
self.update_file_handle = open("_" + _name_new_file, "a")
if self.upgrade_is_secure():
self.do_decrypt = True # starts decryption only when this callback is closed
self.subscribe_task = _name_new_file # subscribe to receive update file
self.message_incoming = bytes()
elif _topic_name == self.manifest.new['files'][self.update_file_index]['name']:
self.update_file_size += len(_message)
self.print_progress_download()
if self.upgrade_is_secure():
self.message_incoming += _message
_chunks = int(len(self.message_incoming)/16)
_message = self.message_incoming[0:_chunks*16]
self.message_incoming = self.message_incoming[_chunks*16:]
_message = self.security.aes_256_cbc_decrypt(_message)
if self.update_file_size == self.manifest.new['files'][self.update_file_index]['size']: # finish download file
_message = unpad(_message)
self.security.sha256_update(_message)
if self.manifest.new['type'] == 'bin':
self.memory.write(_message)
else:
self.update_file_handle.write(_message)
if self.update_file_size == self.manifest.new['files'][self.update_file_index]['size']: # finish download file
if self.manifest.new['type'] == 'bin':
self.memory.flush() # save remaining bytes
else:
self.update_file_handle.close() # close update file
if self.verify_file():
if self.upgrade_is_secure():
self.print_debug("signature verification successfully.")
self.update_file_index += 1 # another file received
self.update_file_size = 0
if self.update_file_index == len(self.manifest.new['files']): # downloaded all files ?
for _file in self.manifest.new['files']:
self.unsubscribe_from_topic(_file['name'])
self.callback_on_receive_update()
else:
_name_new_file = self.manifest.new['files'][self.update_file_index]['name']
self.update_file_handle = open("_" + _name_new_file, "a") # open another file
self.subscribe_task = _name_new_file # subscribe to receive update file
if self.upgrade_is_secure():
self.security.aes_256_cbc_init(self.aes_random_key)
else:
self.print_debug("signature verify failed.")
self.update_file_index = 0
self.update_file_size = 0
self.message_incoming = bytes()
files = os.listdir()
for _file in self.manifest.new['files']:
self.unsubscribe_from_topic(_file['name'])
for file in files: # removes garbage
if file[0] == '_': # is an update file (_xxx)
os.remove(file)
self.message_incoming = bytes()
else:
self.print_debug("topic not recognitzed: " + _topic_name)
self.message_incoming = bytes()
def parse_topic(self, _topic_str):
"""
parse iota topic: iota/<uuid>/<version>/<type>.
Check if topic is valid and from iota.
Args:
_topic_str (string): topic name.
Returns:
<type> of topic.
"""
topic_splitted = _topic_str.split("/")
# message is from IOTA ?
if len(topic_splitted) == 4 and topic_splitted[0] == "iota":
# is for me ?
if topic_splitted[1] == self.manifest.uuid_project:
# version is the desired one
if topic_splitted[2] == str(self.manifest.get_next_version()):
return topic_splitted[3]
if topic_splitted[2] == str(self.manifest.version):
self.print_debug("device up to date")
return ""
def print_progress_download(self):
"""
print the update file download progress
Args:
void
Returns:
void.
"""
_progress = str(100*self.update_file_size/self.manifest.new['files'][self.update_file_index]['size'])
_name_file = str(self.manifest.new['files'][self.update_file_index]['name'])
self.print_debug("downloading update file: '"+_name_file+"' - progress: "+_progress+"%")
def loop(self):
"""
eternal loop necessary to process MQTT stack.
Args:
void.
Returns:
never returns.
"""
if self.do_decrypt == True: # decryption have priority
self.do_decrypt = False
try:
self.aes_random_key = self.security.rsa_decrypt(self.private_key, self.manifest.new['key'])
except Exception:
self.print_debug('decryption AES key failed.')
self.subscribe_task = '' # cancel upgrade
return
print('aes secret random key: ', self.aes_random_key)
self.security.aes_256_cbc_init(self.aes_random_key)
if not self.subscribe_task == '':
self.subscribe_on_topic(self.subscribe_task)
self.subscribe_task = ''
self.mqtt_client.wait_msg()
def print_debug(self, _message):
"""
print debug messages.
Args:
_message (string): message to plot.
Returns:
void.
"""
if self.debug:
print('fotasuit: ', _message)
class Manifest:
"""
initialize manifest class
Args:
_next_partition_name (string): attached to the manifest to determine which
partition should be booted after the upgrade
_pubkey (string): public key from server.
_debug (boolean, optional): enable debug from class. Default is True.
Returns:
object from class.
"""
def __init__(self, _next_partition_name, _public_key=None, _debug=True):
self.debug = _debug
self.next_partition_name = _next_partition_name
self.public_key = _public_key
self.security = Security()
self.uuid_project = ''
self.version = 0
self.date_expiration = ''
self.type = ''
self.new = {}
def load(self, _uuid_project, _version):
"""
the manifest will be loaded from the last downloaded manifest or a default
manifest will be created with the uuid of project and version passed
as a parameter by the user.
_uuid_project (string): universal unique id from project to create default manifest
(only used if not exists an local manifest).
_version (integer): current version of device to create a default manifest
(only used if not exists an local manifest).
Returns:
void
"""
files = os.listdir()
# create default manifest, if necessary. (only in first execution)
if not 'manifest.json' in files:
_manifest_file = open('manifest.json', 'x')
_manifest_str = self.get_default(_uuid_project, _version)
_manifest_file.write(_manifest_str)
_manifest_file.close()
_manifest_file = open('manifest.json', 'r')
_manifest_str = _manifest_file.read()
_manifest_file.close()
self.fill(_manifest_str) # load manifest
self.print_debug("current manifest:\n" + _manifest_str)
def save(self, _new_manifest_object):
"""
saves the new manifest file to the file system.
NOT update the RAM manifest.
Args:
_new_manifest_str (object): manifest in dict format.
Returns:
boolean indicating success of operation.
"""
try:
_new_manifest_str = json.dumps(_new_manifest_object)
except ValueError:
self.print_debug("error. invalid manifest file.")
return False
_manifest_file = open('_manifest.json', 'x')
_manifest_file.write(_new_manifest_str)
_manifest_file.close()
#TODO: check this question!
# self.load(_new_manifest_str) # for now, only reloads manifest in RAM after reboot.
self.new = dict() # clean
if 'key' in _new_manifest_object: # secure version?
self.new['key'] = _new_manifest_object['key']
self.new['type'] = _new_manifest_object['type']
self.new['files'] = _new_manifest_object['files'].copy(
) # update files is stored here!
return True
def save_new(self, _str):
"""
set new manifest file.
Args:
_str (string): manifest in JWS format "data_in_b64.signature_in_b64".
Returns:
boolean indicating status of parsing.
"""
_splitted = _str.split('.')
_data_b64 = _splitted[0]
_data_bytes = ubinascii.a2b_base64(_data_b64)
_data_str = _data_bytes.decode('utf-8')
self.print_debug('message: ' + _data_str)
if len(_splitted) > 1: # was signed ?
_sign_b64 = _splitted[1]
_sign_json_str = ubinascii.a2b_base64(_sign_b64).decode('utf-8')
self.print_debug('signature_json: ' + _sign_json_str)
try:
_sign_object = json.loads(_sign_json_str)
if "sign" in _sign_object:
_sign_str = _sign_object['sign']
self.security.sha256_update(_data_bytes)
_hash = self.security.sha256_ret()
if not self.security.ecdsa_secp256k1_verifiy_sign(
self.public_key, _hash, _sign_str):
self.print_debug("signature verify failed.")
return False
else:
self.print_debug(
"signature verification successfully.")
else:
self.print_debug("error. sign object.")
return False
except Exception as err:
print(err)
self.print_debug("error. signature verify.")
return False
try:
_manifest_object = json.loads(_data_str)
except ValueError:
self.print_debug("error. invalid manifest file.")
return False
# is for this device and is the desired version ?
if _manifest_object['uuidProject'] == self.uuid_project and \
_manifest_object['version'] == self.get_next_version():
# TODO: check others informations like dateExpiration
if _manifest_object['type'] == "bin":
# sets parition wich must be booted after upgrade
# used to verify sucessfull of upgrade
_manifest_object['ota'] = self.next_partition_name
return self.save(_manifest_object)
elif _manifest_object['type'] == "py":
return self.save(_manifest_object)
return False
def fill(self, _manifest_str):
"""
fill manifest object from string.
Args:
_manifest_str (string): manifest file in string format.
Returns:
boolean indicating loading status.
"""
try:
_manifest_object = json.loads(_manifest_str)
self.uuid_project = _manifest_object['uuidProject']
self.version = _manifest_object['version']
self.date_expiration = _manifest_object['dateExpiration']
self.type = _manifest_object['type']
except ValueError:
raise ValueError("can't fill manifest file.")
def get_default(self, _uuid_project, _version):
"""
returns default manifest file with _uuid_project and _version provided.
Args:
_uuid_project (string): universal unique id from project.
_version (integer): Current version of device.
Returns:
string with minimal manifest.
"""
_default_manifest = '{"uuidProject":"' + _uuid_project + '", "version":' + str(
_version)
_default_manifest += ', "dateExpiration": "", "type": ""'
_default_manifest += ', "files": [{"name": "", "size": 0}]}'
return _default_manifest
def get_next_version(self):
"""
returns the new version based on the standard established
by IOTA framework for version management.
Args:
void.
Returns:
integer with new version.
"""
return self.version + 1
def print_debug(self, _message):
"""
print debug messages.
Args:
_message (string): message to plot.
Returns:
void.
"""
if self.debug:
print('manifest: ', _message)