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wolfBoot/tools/keytools/sign.py

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#!/usr/bin/python3
'''
* sign.py
*
* Copyright (C) 2021 wolfSSL Inc.
*
* This file is part of wolfBoot.
*
* wolfBoot is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* wolfBoot is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335, USA
'''
import sys, os, struct, time, re
from wolfcrypt import ciphers, hashes
WOLFBOOT_MAGIC = 0x464C4F57
HDR_END = 0x00
HDR_VERSION = 0x01
HDR_TIMESTAMP = 0x02
HDR_SHA256 = 0x03
HDR_IMG_DELTA_BASE = 0x05
HDR_IMG_DELTA_SIZE = 0x06
HDR_SHA3_384 = 0x13
HDR_IMG_DELTA_INVERSE = 0x15
HDR_IMG_DELTA_INVERSE_SIZE = 0x16
HDR_IMG_TYPE = 0x04
HDR_PUBKEY = 0x10
HDR_SIGNATURE = 0x20
HDR_PADDING = 0xFF
HDR_VERSION_LEN = 4
HDR_TIMESTAMP_LEN = 8
HDR_SHA256_LEN = 32
HDR_SHA3_384_LEN = 48
HDR_IMG_TYPE_LEN = 2
HDR_SIGNATURE_LEN = 64
HDR_IMG_TYPE_AUTH_NONE = 0xFF00
HDR_IMG_TYPE_AUTH_ED25519 = 0x0100
HDR_IMG_TYPE_AUTH_ECC256 = 0x0200
HDR_IMG_TYPE_AUTH_RSA2048 = 0x0300
HDR_IMG_TYPE_AUTH_RSA4096 = 0x0400
HDR_IMG_TYPE_AUTH_ED448 = 0x0500
HDR_IMG_TYPE_DIFF = 0x00D0
HDR_IMG_TYPE_WOLFBOOT = 0x0000
HDR_IMG_TYPE_APP = 0x0001
WOLFBOOT_HEADER_SIZE = 256
sign="auto"
self_update=False
sha_only=False
manual_sign=False
encrypt=False
chacha=True
aes128=False
aes256=False
delta=False
encrypt_key_file=None
delta_base_file=None
argc = len(sys.argv)
argv = sys.argv
hash_algo='sha256'
def make_header(image_file, fw_version, extra_fields=[]):
img_size = os.path.getsize(image_file)
# Magic header (spells 'WOLF')
header = struct.pack('<L', WOLFBOOT_MAGIC)
# Image size
header += struct.pack('<L', img_size)
# No pad bytes, version is aligned
# Version field
header += struct.pack('<HH', HDR_VERSION, HDR_VERSION_LEN)
header += struct.pack('<L', fw_version)
# Four pad bytes, so timestamp is aligned
header += struct.pack('BB', HDR_PADDING, HDR_PADDING)
header += struct.pack('BB', HDR_PADDING, HDR_PADDING)
# Timestamp field
header += struct.pack('<HH', HDR_TIMESTAMP, HDR_TIMESTAMP_LEN)
header += struct.pack('<Q', int(os.path.getmtime(image_file)))
# Image type field
header += struct.pack('<HH', HDR_IMG_TYPE, HDR_IMG_TYPE_LEN)
if (sign == 'none'):
img_type = HDR_IMG_TYPE_AUTH_NONE
if (sign == 'ed25519'):
img_type = HDR_IMG_TYPE_AUTH_ED25519
if (sign == 'ed448'):
img_type = HDR_IMG_TYPE_AUTH_ED448
if (sign == 'ecc256'):
img_type = HDR_IMG_TYPE_AUTH_ECC256
if (sign == 'rsa2048'):
img_type = HDR_IMG_TYPE_AUTH_RSA2048
if (sign == 'rsa4096'):
img_type = HDR_IMG_TYPE_AUTH_RSA4096
if (not self_update):
img_type |= HDR_IMG_TYPE_APP
if (delta and len(extra_fields) > 0):
img_type |= HDR_IMG_TYPE_DIFF
header += struct.pack('<H', img_type)
for t in extra_fields:
tag = t[0]
sz = t[1]
if sz == 4:
while (len(header) % 4) != 0:
header += struct.pack('B', HDR_PADDING)
elif sz == 8:
while (len(header) % 8) != 4:
header += struct.pack('B', HDR_PADDING)
payload = t[2]
header += struct.pack('<HH', tag, sz)
header += payload
# Pad bytes. Sha-3 field requires 8-byte alignment
while (len(header) % 8) != 4:
header += struct.pack('B', HDR_PADDING)
print("Calculating %s digest..." % hash_algo)
if hash_algo == 'sha256':
sha = hashes.Sha256.new()
# Sha calculation
sha.update(header)
img_bin = open(image_file, 'rb')
while True:
buf = img_bin.read(32)
if (len(buf) == 0):
img_bin.close()
break
sha.update(buf)
digest = sha.digest()
# Add SHA to the header
header += struct.pack('<HH', HDR_SHA256, HDR_SHA256_LEN)
header += digest
if sign != 'none':
# pubkey SHA calculation
keysha = hashes.Sha256.new()
keysha.update(pubkey)
key_digest = keysha.digest()
header += struct.pack('<HH', HDR_PUBKEY, HDR_SHA256_LEN)
header += key_digest
elif hash_algo == 'sha3':
sha = hashes.Sha3.new()
# Sha calculation
sha.update(header)
img_bin = open(image_file, 'rb')
while True:
buf = img_bin.read(128)
if (len(buf) == 0):
img_bin.close()
break
sha.update(buf)
digest = sha.digest()
# Add SHA to the header
header += struct.pack('<HH', HDR_SHA3_384, HDR_SHA3_384_LEN)
header += digest
if sign != 'none':
# pubkey SHA calculation
keysha = hashes.Sha3.new()
keysha.update(pubkey)
key_digest = keysha.digest()
header += struct.pack('<HH', HDR_PUBKEY, HDR_SHA3_384_LEN)
header += key_digest
#print("Image Hash %d" % len(digest))
#print([hex(j) for j in digest])
#print ("Pubkey: %d" % len(pubkey))
#print([hex(j) for j in pubkey])
#print("Pubkey Hash %d" % len(key_digest))
#print([hex(j) for j in key_digest])
if sha_only:
outfile = open(output_image_file, 'wb')
outfile.write(digest)
outfile.close()
print("Digest image " + output_image_file +" successfully created.")
print()
sys.exit(0)
if sign != 'none':
# Sign the digest
if not manual_sign:
print("Signing the firmware...")
if (sign == 'ed25519'):
signature = ed.sign(digest)
elif (sign == 'ed448'):
signature = ed.sign(digest)
elif (sign == 'ecc256'):
r, s = ecc.sign_raw(digest)
signature = r + s
elif (sign == 'rsa2048') or (sign == 'rsa4096'):
signature = rsa.sign(digest)
#plain = rsa.verify(signature)
#print("plain:%d " % len(plain))
#print([hex(j) for j in plain])
else:
print("Opening signature file %s" % signature_file)
signfile = open(signature_file, 'rb')
buf = signfile.read(1024)
signfile.close()
if len(buf) != HDR_SIGNATURE_LEN:
print("Wrong signature file size %d, expected %d" % (len(buf), HDR_SIGNATURE_LEN))
sys.exit(4)
signature = buf
header += struct.pack('<HH', HDR_SIGNATURE, HDR_SIGNATURE_LEN)
header += signature
#print ("Signature %d" % len(signature))
#print([hex(j) for j in signature])
print ("Done.")
return header
#### MAIN ####
if (argc < 4) or (argc > 10):
print("Usage: %s [--ed25519 | --ed448 | --ecc256 | --rsa2048 | --rsa4096 | --no-sign] [--sha256 | --sha3] [--wolfboot-update] [--encrypt key.bin] [--delta base_file.bin] image key.der fw_version\n" % sys.argv[0])
print(" - or - ")
print(" %s [--sha256 | --sha3] [--sha-only] [--wolfboot-update] [--encrypt key.bin] [--delta base_file.bin] image pub_key.der fw_version\n" % sys.argv[0])
print(" - or - ")
print(" %s [--ed25519 | --ed448 | --ecc256 | --rsa2048 | --rsa4096 ] [--sha256 | --sha3] [--manual-sign] [--chacha | --aes128 | --aes256 ] [--encrypt key.bin] [--delta base_file.bin] image pub_key.der fw_version signature.sig\n" % sys.argv[0])
sys.exit(1)
i = 1
while (i < len(argv)):
if (argv[i] == '--no-sign'):
sign='none'
elif (argv[i] == '--ed25519'):
sign='ed25519'
elif (argv[i] == '--ed448'):
sign='ed448'
elif (argv[i] == '--ecc256'):
sign='ecc256'
elif (argv[i] == '--rsa2048'):
sign='rsa2048'
elif (argv[i] == '--rsa4096'):
sign='rsa4096'
elif (argv[i] == '--sha256'):
hash_algo='sha256'
elif (argv[i] == '--sha3'):
hash_algo='sha3'
elif (argv[i] == '--wolfboot-update'):
self_update = True
elif (argv[i] == '--sha-only'):
sha_only = True
elif (argv[i] == '--manual-sign'):
manual_sign = True
elif (argv[i] == '--encrypt'):
encrypt = True
i += 1
encrypt_key_file = argv[i]
elif (argv[i] == '--chacha'):
encrypt = True
elif (argv[i] == '--aes128'):
encrypt = True
chacha = False
aes128 = True
elif (argv[i] == '--aes256'):
encrypt = True
chacha = False
aes256 = True
elif (argv[i] == '--delta'):
delta = True
i += 1
delta_base_file = argv[i]
else:
i-=1
break
i += 1
if (encrypt and delta):
print("Encryption of delta images not supported yet.")
sys.exit(1)
try:
cfile = open(".config", "r")
except:
cfile = None
pass
if cfile:
l = cfile.readline()
while l != '':
if "IMAGE_HEADER_SIZE" in l:
val=l.split('=')[1].rstrip('\n')
WOLFBOOT_HEADER_SIZE = int(val,0)
print("IMAGE_HEADER_SIZE (from .config): " + str(WOLFBOOT_HEADER_SIZE))
l = cfile.readline()
cfile.close()
image_file = argv[i+1]
if sign != 'none':
key_file = argv[i+2]
fw_version = int(argv[i+3])
else:
key_file = ''
fw_version = int(argv[i+2])
if manual_sign:
signature_file = argv[i+4]
if not sha_only:
if '.' in image_file:
tokens = image_file.split('.')
output_image_file = image_file.rstrip('.' + tokens[-1])
output_image_file += "_v" + str(fw_version) + "_signed.bin"
else:
output_image_file = image_file + "_v" + str(fw_version) + "_signed.bin"
else:
if '.' in image_file:
tokens = image_file.split('.')
output_image_file = image_file.rstrip('.' + tokens[-1])
output_image_file += "_v" + str(fw_version) + "_digest.bin"
else:
output_image_file = image_file + "_v" + str(fw_version) + "_digest.bin"
if encrypt:
if '.' in image_file:
tokens = image_file.split('.')
encrypted_output_image_file = image_file.rstrip('.' + tokens[-1])
encrypted_output_image_file += "_v" + str(fw_version) + "_signed_and_encrypted.bin"
else:
encrypted_output_image_file = image_file + "_v" + str(fw_version) + "_signed_and_encrypted.bin"
elif delta:
if '.' in image_file:
tokens = image_file.split('.')
delta_output_image_file = image_file.rstrip('.' + tokens[-1])
delta_output_image_file += "_v" + str(fw_version) + "_signed_diff.bin"
else:
delta_output_image_file = image_file + "_v" + str(fw_version) + "_signed_diff.bin"
if (self_update):
print("Update type: wolfBoot")
else:
print("Update type: Firmware")
print ("Input image: " + image_file)
print ("Selected cipher: " + sign)
print ("Public key: " + key_file)
if not sha_only:
print ("Output image: " + output_image_file)
else:
print ("Output digest: " + output_image_file)
if not encrypt:
print ("Not Encrypted")
else:
print ("Encrypted using: " + encrypt_key_file)
if sign == 'none':
kf = None
wolfboot_key_buffer=''
wolfboot_key_buffer_len = 0
else:
kf = open(key_file, "rb")
wolfboot_key_buffer = kf.read(4096)
wolfboot_key_buffer_len = len(wolfboot_key_buffer)
if wolfboot_key_buffer_len == 0:
if (sign != 'none'):
print("Error. Key size is zero but cipher is " + sign)
sys.exit(3)
print("*** WARNING: cipher 'none' selected.")
print("*** Image will not be authenticated!")
print("*** SECURE BOOT DISABLED.")
elif wolfboot_key_buffer_len == 32:
if (sign != 'ed25519' and not manual_sign and not sha_only):
print("Error: key too short for cipher")
sys.exit(1)
elif sign == 'auto' and (manual_sign or sha_only):
sign = 'ed25519'
print("'ed25519' public key autodetected.")
elif wolfboot_key_buffer_len == 64:
if (sign == 'ecc256'):
if not manual_sign and not sha_only:
print("Error: key size does not match the cipher selected")
sys.exit(1)
else:
print("Ecc256 public key detected")
if sign == 'auto':
if (manual_sign or sha_only):
sign = 'ecc256'
print("'ecc256' public key autodetected.")
else:
sign = 'ed25519'
print("'ed25519' key autodetected.")
elif wolfboot_key_buffer_len == 114:
if (sign != 'ed448' and not manual_sign and not sha_only):
print("Error: key size incorrect for cipher")
sys.exit(1)
elif sign == 'auto' and (manual_sign or sha_only):
sign = 'ed448'
print("'ed448' public key autodetected.")
elif wolfboot_key_buffer_len == 96:
if (sign == 'ed25519'):
print("Error: key size does not match the cipher selected")
sys.exit(1)
if sign == 'auto':
sign = 'ecc256'
print("'ecc256' key autodetected.")
elif (wolfboot_key_buffer_len > 512):
if (sign == 'auto'):
print("'rsa4096' key autodetected.")
elif (wolfboot_key_buffer_len > 128):
if (sign == 'auto'):
print("'rsa2048' key autodetected.")
elif (sign != 'rsa2048'):
print ("Error: key size too large for the selected cipher")
else:
print ("Error: key size does not match any cipher")
sys.exit(2)
if sign == 'none':
privkey = None
pubkey = None
elif not sha_only and not manual_sign:
''' import (decode) private key for signing '''
if sign == 'ed25519':
ed = ciphers.Ed25519Private(key = wolfboot_key_buffer)
privkey, pubkey = ed.encode_key()
if sign == 'ed448':
HDR_SIGNATURE_LEN = 114
if WOLFBOOT_HEADER_SIZE < 512:
WOLFBOOT_HEADER_SIZE = 512
ed = ciphers.Ed448Private(key = wolfboot_key_buffer)
privkey, pubkey = ed.encode_key()
if sign == 'ecc256':
ecc = ciphers.EccPrivate()
ecc.decode_key_raw(wolfboot_key_buffer[0:32], wolfboot_key_buffer[32:64], wolfboot_key_buffer[64:])
pubkey = wolfboot_key_buffer[0:64]
if sign == 'rsa2048':
if WOLFBOOT_HEADER_SIZE < 512:
WOLFBOOT_HEADER_SIZE = 512
HDR_SIGNATURE_LEN = 256
rsa = ciphers.RsaPrivate(wolfboot_key_buffer)
privkey,pubkey = rsa.encode_key()
if sign == 'rsa4096':
if WOLFBOOT_HEADER_SIZE < 1024:
WOLFBOOT_HEADER_SIZE = 1024
HDR_SIGNATURE_LEN = 512
rsa = ciphers.RsaPrivate(wolfboot_key_buffer)
privkey,pubkey = rsa.encode_key()
else:
if sign == 'rsa2048':
if WOLFBOOT_HEADER_SIZE < 512:
WOLFBOOT_HEADER_SIZE = 512
HDR_SIGNATURE_LEN = 256
if sign == 'rsa4096':
if WOLFBOOT_HEADER_SIZE < 512:
WOLFBOOT_HEADER_SIZE = 1024
HDR_SIGNATURE_LEN = 512
pubkey = wolfboot_key_buffer
header = make_header(image_file, fw_version)
# Create output image. Add padded header in front
outfile = open(output_image_file, 'wb')
outfile.write(header)
sz = len(header)
while sz < WOLFBOOT_HEADER_SIZE:
outfile.write(struct.pack('B',HDR_PADDING))
sz += 1
infile = open(image_file, 'rb')
while True:
buf = infile.read(1024)
if len(buf) == 0:
break
outfile.write(buf)
infile.close()
outfile.close()
if (delta):
tmp_outfile='/tmp/delta.bin'
tmp_inv_outfile='/tmp/delta-1.bin'
os.system('tools/delta/bmdiff ' + delta_base_file + ' ' + output_image_file + ' ' + tmp_outfile)
os.system('tools/delta/bmdiff ' + output_image_file + ' ' + delta_base_file + ' ' + tmp_inv_outfile)
delta_size = os.path.getsize(tmp_outfile)
delta_inv_size = os.path.getsize(tmp_inv_outfile)
delta_file = open(tmp_outfile, 'ab+')
delta_inv_file = open(tmp_inv_outfile, 'rb')
while delta_file.tell() % 16 != 0:
delta_file.write(struct.pack('B', 0x00))
inv_off = delta_file.tell()
while True:
cpbuf = delta_inv_file.read(1024)
if len(cpbuf) == 0:
break
delta_file.write(cpbuf)
delta_file.close()
delta_inv_file.close()
base_version = re.split("_", (re.split("_v", delta_base_file)[1]))[0]
header = make_header(tmp_outfile, fw_version,
[[HDR_IMG_DELTA_BASE, 4, struct.pack("<L", int(base_version))],
[HDR_IMG_DELTA_SIZE, 2, struct.pack("<H", delta_size)],
[HDR_IMG_DELTA_INVERSE, 4, struct.pack("<L", inv_off + WOLFBOOT_HEADER_SIZE)],
[HDR_IMG_DELTA_INVERSE_SIZE, 2, struct.pack("<H", delta_inv_size)]
])
outfile = open(delta_output_image_file, 'wb')
outfile.write(header)
sz = len(header)
while sz < WOLFBOOT_HEADER_SIZE:
outfile.write(struct.pack('B', HDR_PADDING))
sz += 1
infile = open(tmp_outfile, 'rb')
while True:
buf = infile.read(1024)
if len(buf) == 0:
break
outfile.write(buf)
infile.close()
outfile.close()
os.remove(tmp_outfile)
os.remove(tmp_inv_outfile)
if (encrypt):
sz = 0
off = 0
outfile = open(output_image_file, 'rb')
ekeyfile = open(encrypt_key_file, 'rb')
enc_outfile = open(encrypted_output_image_file, 'wb')
if chacha:
key = ekeyfile.read(32)
iv_nonce = ekeyfile.read(12)
cha = ciphers.ChaCha(key, 32)
cha.set_iv(iv_nonce, 0)
while True:
buf = outfile.read(16)
if len(buf) == 0:
break
enc_outfile.write(cha.encrypt(buf))
elif aes128:
key = ekeyfile.read(16)
iv = ekeyfile.read(16)
aesctr = ciphers.Aes(key, ciphers.MODE_CTR, iv)
while True:
buf = outfile.read(16)
if len(buf) == 0:
break
while (len(buf) % 16) != 0:
buf += struct.pack('B', HDR_PADDING)
enc_outfile.write(aesctr.encrypt(buf))
elif aes256:
key = ekeyfile.read(32)
iv = ekeyfile.read(16)
aesctr = ciphers.Aes(key, ciphers.MODE_CTR, iv)
while True:
buf = outfile.read(16)
if len(buf) == 0:
break
while (len(buf) % 16) != 0:
buf += struct.pack('B', HDR_PADDING)
enc_outfile.write(aesctr.encrypt(buf))
outfile.close()
ekeyfile.close()
enc_outfile.close()
print ("Output image successfully created.")
sys.exit(0)
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