mirror of
https://github.com/espressif/esp-idf.git
synced 2024-09-21 06:56:11 -04:00
222 lines
7.6 KiB
Python
222 lines
7.6 KiB
Python
#!/usr/bin/env python
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# Copyright 2020 Espressif Systems (Shanghai) Co., Ltd.
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import argparse
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import os
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import sys
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import hashlib
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import hmac
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import struct
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from cryptography.hazmat.backends import default_backend
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from cryptography.hazmat.primitives import serialization
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from cryptography.hazmat.primitives.asymmetric import rsa
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from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
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from cryptography.utils import int_to_bytes
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try:
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import nvs_partition_gen as nvs_gen
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except ImportError:
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idf_path = os.getenv("IDF_PATH")
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if not idf_path or not os.path.exists(idf_path):
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raise Exception("IDF_PATH not found")
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sys.path.insert(0, os.path.join(idf_path, "components", "nvs_flash", "nvs_partition_generator"))
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import nvs_partition_gen as nvs_gen
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esp_ds_data_dir = 'esp_ds_data'
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# hmac_key_file is generated when HMAC_KEY is calculated, it is used when burning HMAC_KEY to efuse
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hmac_key_file = esp_ds_data_dir + '/hmac_key.bin'
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# csv and bin filenames are default filenames for nvs partition files created with this script
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csv_filename = esp_ds_data_dir + '/pre_prov.csv'
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bin_filename = esp_ds_data_dir + '/pre_prov.bin'
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def load_privatekey(key_file_path, password=None):
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key_file = open(key_file_path, 'rb')
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key = key_file.read()
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key_file.close()
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return serialization.load_pem_private_key(key, password=password, backend=default_backend())
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def number_as_bytes(number, pad_bits=None):
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"""
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Given a number, format as a little endian array of bytes
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"""
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result = int_to_bytes(number)[::-1]
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while pad_bits is not None and len(result) < (pad_bits // 8):
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result += b'\x00'
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return result
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def calculate_ds_parameters(privkey, priv_key_pass):
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private_key = load_privatekey(privkey, priv_key_pass)
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if not isinstance(private_key, rsa.RSAPrivateKey):
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print("Only RSA private keys are supported")
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sys.exit(-1)
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priv_numbers = private_key.private_numbers()
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pub_numbers = private_key.public_key().public_numbers()
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Y = priv_numbers.d
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M = pub_numbers.n
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key_size = private_key.key_size
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supported_key_size = [1024, 2048, 3072, 4096]
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if key_size not in supported_key_size:
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print("Key size not supported, supported sizes are" + str(supported_key_size))
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sys.exit(-1)
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hmac_key = os.urandom(32)
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with open(hmac_key_file, 'wb') as key_file:
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key_file.write(hmac_key)
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iv = os.urandom(16)
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rr = 1 << (key_size * 2)
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rinv = rr % pub_numbers.n
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mprime = - rsa._modinv(M, 1 << 32)
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mprime &= 0xFFFFFFFF
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length = key_size // 32 - 1
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aes_key = hmac.HMAC(hmac_key, b"\xFF" * 32, hashlib.sha256).digest()
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md_in = number_as_bytes(Y, 4096) + \
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number_as_bytes(M, 4096) + \
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number_as_bytes(rinv, 4096) + \
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struct.pack("<II", mprime, length) + \
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iv
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assert len(md_in) == 12480 / 8
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md = hashlib.sha256(md_in).digest()
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# Y4096 || M4096 || Rb4096 || M_prime32 || LENGTH32 || MD256 || 0x08*8
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p = number_as_bytes(Y, 4096) + \
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number_as_bytes(M, 4096) + \
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number_as_bytes(rinv, 4096) + \
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md + \
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struct.pack("<II", mprime, length) + \
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b'\x08' * 8
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assert len(p) == 12672 / 8
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cipher = Cipher(algorithms.AES(aes_key), modes.CBC(iv), backend=default_backend())
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encryptor = cipher.encryptor()
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c = encryptor.update(p) + encryptor.finalize()
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return c, iv, key_size
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def efuse_summary(args):
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os.system("python $IDF_PATH/components/esptool_py/esptool/espefuse.py --chip esp32s2 -p %s summary" % (args.port))
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def efuse_burn_key(args):
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os.system("python $IDF_PATH/components/esptool_py/esptool/espefuse.py --chip esp32s2 -p %s burn_key "
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"%s %s HMAC_DOWN_DIGITAL_SIGNATURE --no-read-protect"
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% ((args.port), ("BLOCK_KEY" + str(args.efuse_key_id)), (hmac_key_file)))
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def generate_csv_file(c, iv, hmac_key_id, key_size, csv_file):
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with open(csv_file, 'wt', encoding='utf8') as f:
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f.write("# This is a generated csv file containing required parameters for the Digital Signature operaiton\n")
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f.write("key,type,encoding,value\nesp_ds_ns,namespace,,\n")
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f.write("esp_ds_c,data,hex2bin,%s\n" % (c.hex()))
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f.write("esp_ds_iv,data,hex2bin,%s\n" % (iv.hex()))
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f.write("esp_ds_key_id,data,u8,%d\n" % (hmac_key_id))
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f.write("esp_ds_rsa_len,data,u16,%d\n" % (key_size))
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class DefineArgs(object):
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def __init__(self, attributes):
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for key, value in attributes.items():
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self.__setattr__(key, value)
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def generate_nvs_partition(input_filename, output_filename):
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nvs_args = DefineArgs({
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'input': input_filename,
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'outdir': os.getcwd(),
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'output': output_filename,
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'size': hex(0x3000),
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'version': 2,
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'keyfile':None,
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})
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nvs_gen.generate(nvs_args, is_encr_enabled=False, encr_key=None)
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def main():
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parser = argparse.ArgumentParser(description='''Genereate an nvs partition containing the DS private key parameters from the client private key,
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Generate an HMAC key and burn it in the desired efuse key block (required for Digital Signature)''')
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parser.add_argument(
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'--private-key',
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dest='privkey',
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default='main/client.key',
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metavar='relative/path/to/client-priv-key',
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help='relative path to client private key')
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parser.add_argument(
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"--pwd", '--password',
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dest='priv_key_pass',
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metavar='[password]',
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help='the password associated with the private key')
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parser.add_argument(
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'--summary',
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dest='summary',action='store_true',
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help='Provide this option to print efuse summary the chip')
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parser.add_argument(
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'--efuse_key_id',
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dest='efuse_key_id', type=int, choices=range(1,6),
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metavar='[key_id] ',
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default=1,
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help='Provide the efuse key_id which contains/will contain HMAC_KEY, default is 1')
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parser.add_argument(
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"--port", '-p',
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dest='port',
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metavar='[port]',
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required=True,
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help='UART com port to which ESP device is connected')
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parser.add_argument(
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'--overwrite',
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dest='overwrite', action='store_true',
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help='Overwrite previously generated keys')
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args = parser.parse_args()
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if args.summary is not False:
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efuse_summary(args)
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sys.exit(0)
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if (os.path.exists(esp_ds_data_dir) is False):
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os.makedirs(esp_ds_data_dir)
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else:
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if (args.overwrite is False):
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print("WARNING: previous ecrypted private key data exists.\nIf you want to overwrite,"
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" please execute your command with providing \"--overwrite\" option")
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sys.exit(0)
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else:
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print("overwriting previous encrypted private key data, as you have provided \"--overwrite\" option")
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c, iv, key_size = calculate_ds_parameters(args.privkey, args.priv_key_pass)
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efuse_burn_key(args)
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generate_csv_file(c, iv, args.efuse_key_id, key_size, csv_filename)
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generate_nvs_partition(csv_filename, bin_filename)
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if __name__ == "__main__":
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main()
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