mirror of
https://github.com/espressif/esp-idf.git
synced 2024-09-21 06:56:11 -04:00
5331bc2c71
the esp32-s2 chip.
* Added option to read and use previously burned efuse keys
* Added option for the user to save the DS parameters for
* development purpose.
* Updated required documentation.
351 lines
14 KiB
Python
351 lines
14 KiB
Python
#!/usr/bin/env python
|
|
# Copyright 2020 Espressif Systems (Shanghai) Co., Ltd.
|
|
# Licensed under the Apache License, Version 2.0 (the "License");
|
|
# you may not use this file except in compliance with the License.
|
|
# You may obtain a copy of the License at
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# Unless required by applicable law or agreed to in writing, software
|
|
# distributed under the License is distributed on an "AS IS" BASIS,
|
|
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
# See the License for the specific language governing permissions and
|
|
# limitations under the License.
|
|
import argparse
|
|
import os
|
|
import sys
|
|
import hashlib
|
|
import hmac
|
|
import struct
|
|
import subprocess
|
|
import json
|
|
from cryptography.hazmat.backends import default_backend
|
|
from cryptography.hazmat.primitives import serialization
|
|
from cryptography.hazmat.primitives.asymmetric import rsa
|
|
from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
|
|
from cryptography.utils import int_to_bytes
|
|
|
|
try:
|
|
import nvs_partition_gen as nvs_gen
|
|
except ImportError:
|
|
idf_path = os.getenv("IDF_PATH")
|
|
if not idf_path or not os.path.exists(idf_path):
|
|
raise Exception("IDF_PATH not found")
|
|
sys.path.insert(0, os.path.join(idf_path, "components", "nvs_flash", "nvs_partition_generator"))
|
|
import nvs_partition_gen as nvs_gen
|
|
|
|
# Check python version is proper or not to avoid script failure
|
|
assert sys.version_info >= (3, 6, 0), "Python version too low."
|
|
|
|
esp_ds_data_dir = 'esp_ds_data'
|
|
# hmac_key_file is generated when HMAC_KEY is calculated, it is used when burning HMAC_KEY to efuse
|
|
hmac_key_file = esp_ds_data_dir + '/hmac_key.bin'
|
|
# csv and bin filenames are default filenames for nvs partition files created with this script
|
|
csv_filename = esp_ds_data_dir + '/pre_prov.csv'
|
|
bin_filename = esp_ds_data_dir + '/pre_prov.bin'
|
|
expected_json_path = os.path.join('build', 'config', 'sdkconfig.json')
|
|
# Targets supported by the script
|
|
supported_targets = {'esp32s2'}
|
|
|
|
|
|
# @return
|
|
# on success idf_target - value of the IDF_TARGET read from build/config/sdkconfig.json
|
|
# on failure None
|
|
def get_idf_target():
|
|
if os.path.exists(expected_json_path):
|
|
sdkconfig = json.load(open(expected_json_path))
|
|
idf_target_read = sdkconfig['IDF_TARGET']
|
|
return idf_target_read
|
|
else:
|
|
print("ERROR: IDF_TARGET has not been set for the supported targets,"
|
|
"\nplase execute command \"idf.py set-target {TARGET}\" in the example directory")
|
|
return None
|
|
|
|
|
|
def load_privatekey(key_file_path, password=None):
|
|
key_file = open(key_file_path, 'rb')
|
|
key = key_file.read()
|
|
key_file.close()
|
|
return serialization.load_pem_private_key(key, password=password, backend=default_backend())
|
|
|
|
|
|
def number_as_bytes(number, pad_bits=None):
|
|
"""
|
|
Given a number, format as a little endian array of bytes
|
|
"""
|
|
result = int_to_bytes(number)[::-1]
|
|
while pad_bits is not None and len(result) < (pad_bits // 8):
|
|
result += b'\x00'
|
|
return result
|
|
|
|
|
|
def calculate_ds_parameters(privkey, priv_key_pass, hmac_key):
|
|
private_key = load_privatekey(privkey, priv_key_pass)
|
|
if not isinstance(private_key, rsa.RSAPrivateKey):
|
|
print("Only RSA private keys are supported")
|
|
sys.exit(-1)
|
|
if hmac_key is None:
|
|
print("hmac_key cannot be None")
|
|
sys.exit(-2)
|
|
|
|
priv_numbers = private_key.private_numbers()
|
|
pub_numbers = private_key.public_key().public_numbers()
|
|
Y = priv_numbers.d
|
|
M = pub_numbers.n
|
|
key_size = private_key.key_size
|
|
supported_key_size = [1024, 2048, 3072, 4096]
|
|
if key_size not in supported_key_size:
|
|
print("Key size not supported, supported sizes are" + str(supported_key_size))
|
|
sys.exit(-1)
|
|
|
|
iv = os.urandom(16)
|
|
|
|
rr = 1 << (key_size * 2)
|
|
rinv = rr % pub_numbers.n
|
|
mprime = - rsa._modinv(M, 1 << 32)
|
|
mprime &= 0xFFFFFFFF
|
|
length = key_size // 32 - 1
|
|
|
|
aes_key = hmac.HMAC(hmac_key, b"\xFF" * 32, hashlib.sha256).digest()
|
|
|
|
md_in = number_as_bytes(Y, 4096) + \
|
|
number_as_bytes(M, 4096) + \
|
|
number_as_bytes(rinv, 4096) + \
|
|
struct.pack("<II", mprime, length) + \
|
|
iv
|
|
assert len(md_in) == 12480 / 8
|
|
md = hashlib.sha256(md_in).digest()
|
|
|
|
# Y4096 || M4096 || Rb4096 || M_prime32 || LENGTH32 || MD256 || 0x08*8
|
|
p = number_as_bytes(Y, 4096) + \
|
|
number_as_bytes(M, 4096) + \
|
|
number_as_bytes(rinv, 4096) + \
|
|
md + \
|
|
struct.pack("<II", mprime, length) + \
|
|
b'\x08' * 8
|
|
|
|
assert len(p) == 12672 / 8
|
|
|
|
cipher = Cipher(algorithms.AES(aes_key), modes.CBC(iv), backend=default_backend())
|
|
encryptor = cipher.encryptor()
|
|
c = encryptor.update(p) + encryptor.finalize()
|
|
return c, iv, key_size
|
|
|
|
|
|
def efuse_summary(args, idf_target):
|
|
os.system("python $IDF_PATH/components/esptool_py/esptool/espefuse.py --chip {0} -p {1} summary".format(idf_target, (args.port)))
|
|
|
|
|
|
def efuse_burn_key(args, idf_target):
|
|
# In case of a development (default) usecase we disable the read protection.
|
|
key_block_status = '--no-read-protect'
|
|
|
|
if args.production is True:
|
|
# Whitespace character will have no additional effect on the command and
|
|
# read protection will be enabled as the default behaviour of the command
|
|
key_block_status = ' '
|
|
|
|
os.system("python $IDF_PATH/components/esptool_py/esptool/espefuse.py --chip {0} -p {1} burn_key "
|
|
"{2} {3} HMAC_DOWN_DIGITAL_SIGNATURE {4}"
|
|
.format((idf_target), (args.port), ("BLOCK_KEY" + str(args.efuse_key_id)), (hmac_key_file), (key_block_status)))
|
|
|
|
|
|
def generate_csv_file(c, iv, hmac_key_id, key_size, csv_file):
|
|
|
|
with open(csv_file, 'wt', encoding='utf8') as f:
|
|
f.write("# This is a generated csv file containing required parameters for the Digital Signature operaiton\n")
|
|
f.write("key,type,encoding,value\nesp_ds_ns,namespace,,\n")
|
|
f.write("esp_ds_c,data,hex2bin,%s\n" % (c.hex()))
|
|
f.write("esp_ds_iv,data,hex2bin,%s\n" % (iv.hex()))
|
|
f.write("esp_ds_key_id,data,u8,%d\n" % (hmac_key_id))
|
|
f.write("esp_ds_rsa_len,data,u16,%d\n" % (key_size))
|
|
|
|
|
|
class DefineArgs(object):
|
|
def __init__(self, attributes):
|
|
for key, value in attributes.items():
|
|
self.__setattr__(key, value)
|
|
|
|
|
|
def generate_nvs_partition(input_filename, output_filename):
|
|
|
|
nvs_args = DefineArgs({
|
|
'input': input_filename,
|
|
'outdir': os.getcwd(),
|
|
'output': output_filename,
|
|
'size': hex(0x3000),
|
|
'version': 2,
|
|
'keyfile':None,
|
|
})
|
|
|
|
nvs_gen.generate(nvs_args, is_encr_enabled=False, encr_key=None)
|
|
|
|
|
|
def get_efuse_summary_json(args, idf_target):
|
|
_efuse_summary = None
|
|
try:
|
|
_efuse_summary = subprocess.check_output(("python $IDF_PATH/components/esptool_py/esptool/espefuse.py "
|
|
"--chip {0} -p {1} summary --format json".format(idf_target, (args.port))), shell=True)
|
|
except subprocess.CalledProcessError as e:
|
|
print((e.output).decode('UTF-8'))
|
|
sys.exit(-1)
|
|
|
|
_efuse_summary = _efuse_summary.decode('UTF-8')
|
|
# Remove everything before actual json data from efuse_summary command output.
|
|
_efuse_summary = _efuse_summary[_efuse_summary.find('{'):]
|
|
try:
|
|
_efuse_summary_json = json.loads(_efuse_summary)
|
|
except json.JSONDecodeError:
|
|
print('ERROR: failed to parse the json output')
|
|
sys.exit(-1)
|
|
return _efuse_summary_json
|
|
|
|
|
|
def configure_efuse_key_block(args, idf_target):
|
|
efuse_summary_json = get_efuse_summary_json(args, idf_target)
|
|
key_blk = 'BLOCK_KEY' + str(args.efuse_key_id)
|
|
key_purpose = 'KEY_PURPOSE_' + str(args.efuse_key_id)
|
|
|
|
kb_writeable = efuse_summary_json[key_blk]['writeable']
|
|
kb_readable = efuse_summary_json[key_blk]['readable']
|
|
hmac_key_read = None
|
|
|
|
# If the efuse key block is writable (empty) then generate and write
|
|
# the new hmac key and check again
|
|
# If the efuse key block is not writable (already contains a key) then check if it is redable
|
|
if kb_writeable is True:
|
|
print('Provided key block is writable\n Generating new key and burning it in the efuse..\n')
|
|
|
|
new_hmac_key = os.urandom(32)
|
|
with open(hmac_key_file, 'wb') as key_file:
|
|
key_file.write(new_hmac_key)
|
|
# Burn efuse key
|
|
efuse_burn_key(args, idf_target)
|
|
# Read fresh summary of the efuse to read the key value from efuse.
|
|
# If the key read from efuse matches with the key generated
|
|
# on host then burn_key operation was successfull
|
|
new_efuse_summary_json = get_efuse_summary_json(args, idf_target)
|
|
hmac_key_read = new_efuse_summary_json[key_blk]['value']
|
|
hmac_key_read = bytes.fromhex(hmac_key_read)
|
|
if new_hmac_key == hmac_key_read:
|
|
print('Key was successfully written in the efuse')
|
|
else:
|
|
print('Error in burning hmac key to efuse ,\nPlease execute the script again using a different key id')
|
|
else:
|
|
# If the efuse key block is redable, then read the key from efuse block and use it for encrypting the RSA private key parameters.
|
|
# If the efuse key block is not redable or it has key purpose set to a different
|
|
# value than "HMAC_DOWN_DIGITAL_SIGNATURE" then we cannot use it for DS operation
|
|
if kb_readable is True:
|
|
if efuse_summary_json[key_purpose]['value'] == 'HMAC_DOWN_DIGITAL_SIGNATURE':
|
|
print("Provided efuse key block already contains a key with key_purpose=HMAC_DOWN_DIGITAL_SIGNATURE,"
|
|
"\nusing the same key for encrypting private key data...\n")
|
|
hmac_key_read = efuse_summary_json[key_blk]['value']
|
|
hmac_key_read = bytes.fromhex(hmac_key_read)
|
|
if args.keep_ds_data is True:
|
|
with open(hmac_key_file, 'wb') as key_file:
|
|
key_file.write(new_hmac_key)
|
|
else:
|
|
print("Provided efuse key block contains a key with key purpose different"
|
|
"than HMAC_DOWN_DIGITAL_SIGNATURE,\nplease execute the script again with a different value of the efuse key id.")
|
|
sys.exit(0)
|
|
else:
|
|
print('Provided efuse key block is not readable and writeable,\nplease execute the script again with a different value of the efuse key id.')
|
|
sys.exit(0)
|
|
|
|
# Return the hmac key read from the efuse
|
|
return hmac_key_read
|
|
|
|
|
|
def cleanup(args):
|
|
if args.keep_ds_data is False:
|
|
if os.path.exists(hmac_key_file):
|
|
os.remove(hmac_key_file)
|
|
if os.path.exists(csv_filename):
|
|
os.remove(csv_filename)
|
|
|
|
|
|
def main():
|
|
parser = argparse.ArgumentParser(description='''Generate an HMAC key and burn it in the desired efuse key block (required for Digital Signature),
|
|
Generates an NVS partition containing the encrypted private key parameters from the client private key.
|
|
''')
|
|
|
|
parser.add_argument(
|
|
'--private-key',
|
|
dest='privkey',
|
|
default='client.key',
|
|
metavar='relative/path/to/client-priv-key',
|
|
help='relative path to client private key')
|
|
|
|
parser.add_argument(
|
|
"--pwd", '--password',
|
|
dest='priv_key_pass',
|
|
metavar='[password]',
|
|
help='the password associated with the private key')
|
|
|
|
parser.add_argument(
|
|
'--summary',
|
|
dest='summary',action='store_true',
|
|
help='Provide this option to print efuse summary of the chip')
|
|
|
|
parser.add_argument(
|
|
'--efuse_key_id',
|
|
dest='efuse_key_id', type=int, choices=range(1,6),
|
|
metavar='[key_id] ',
|
|
default=1,
|
|
help='Provide the efuse key_id which contains/will contain HMAC_KEY, default is 1')
|
|
|
|
parser.add_argument(
|
|
"--port", '-p',
|
|
dest='port',
|
|
metavar='[port]',
|
|
required=True,
|
|
help='UART com port to which the ESP device is connected')
|
|
|
|
parser.add_argument(
|
|
'--keep_ds_data_on_host','-keep_ds_data',
|
|
dest='keep_ds_data', action='store_true',
|
|
help='Keep encrypted private key data and key on host machine for testing purpose')
|
|
|
|
parser.add_argument(
|
|
'--production', '-prod',
|
|
dest='production', action='store_true',
|
|
help='Enable production configurations. e.g.keep efuse key block read protection enabled')
|
|
|
|
args = parser.parse_args()
|
|
|
|
idf_target = get_idf_target()
|
|
if idf_target not in supported_targets:
|
|
if idf_target is not None:
|
|
print('ERROR: The script does not support the target %s' % idf_target)
|
|
sys.exit(-1)
|
|
idf_target = str(idf_target)
|
|
|
|
if args.summary is not False:
|
|
efuse_summary(args, idf_target)
|
|
sys.exit(0)
|
|
|
|
if (os.path.exists(args.privkey) is False):
|
|
print('ERROR: The provided private key file does not exist')
|
|
sys.exit(-1)
|
|
|
|
if (os.path.exists(esp_ds_data_dir) is False):
|
|
os.makedirs(esp_ds_data_dir)
|
|
|
|
# Burn hmac_key on the efuse block (if it is empty) or read it
|
|
# from the efuse block (if the efuse block already contains a key).
|
|
hmac_key_read = configure_efuse_key_block(args, idf_target)
|
|
if hmac_key_read is None:
|
|
sys.exit(-1)
|
|
|
|
# Calculate the encrypted private key data along with all other parameters
|
|
c, iv, key_size = calculate_ds_parameters(args.privkey, args.priv_key_pass, hmac_key_read)
|
|
|
|
# Generate csv file for the DS data and generate an NVS partition.
|
|
generate_csv_file(c, iv, args.efuse_key_id, key_size, csv_filename)
|
|
generate_nvs_partition(csv_filename, bin_filename)
|
|
cleanup(args)
|
|
|
|
|
|
if __name__ == "__main__":
|
|
main()
|