#!/usr/bin/python
+import getpass as _getpass
import hashlib as _hashlib
+import math as _math
import re as _re
import subprocess as _subprocess
import struct as _struct
+import Crypto.Cipher.AES as _crypto_cipher_aes
+import Crypto.Cipher.Blowfish as _crypto_cipher_blowfish
+import Crypto.Cipher.CAST as _crypto_cipher_cast
+import Crypto.Cipher.DES3 as _crypto_cipher_des3
+
def _get_stdout(args, stdin=None):
stdin_pipe = None
'aes with 192-bit key': 128,
'aes with 256-bit key': 128,
'cast5': 64,
+ 'twofish': 128,
+ }
+
+ _crypto_module = {
+ 'aes with 128-bit key': _crypto_cipher_aes,
+ 'aes with 192-bit key': _crypto_cipher_aes,
+ 'aes with 256-bit key': _crypto_cipher_aes,
+ 'blowfish': _crypto_cipher_blowfish,
+ 'cast5': _crypto_cipher_cast,
+ 'tripledes': _crypto_cipher_des3,
+ }
+
+ _key_size = { # in bits
+ 'aes with 128-bit key': 128,
+ 'aes with 192-bit key': 192,
+ 'aes with 256-bit key': 256,
+ 'cast5': 128,
}
_compression_algorithms = {
110: 'private',
}
+ _hashlib_name = { # map OpenPGP-based names to hashlib names
+ 'md5': 'md5',
+ 'sha-1': 'sha1',
+ 'ripe-md/160': 'ripemd160',
+ 'sha256': 'sha256',
+ 'sha384': 'sha384',
+ 'sha512': 'sha512',
+ 'sha224': 'sha224',
+ }
+
_string_to_key_types = {
0: 'simple',
1: 'salted',
110: 'private',
}
+ _string_to_key_expbias = 6
+
_signature_types = {
0x00: 'binary document',
0x01: 'canonical text document',
_clean_type_regex = _re.compile('\W+')
+ def __init__(self, key=None):
+ super(PGPPacket, self).__init__()
+ self.key = key
+
def _clean_type(self, type=None):
if type is None:
type = self['type']
def _str_public_subkey_packet(self):
return self._str_generic_key_packet()
+ def _str_generic_key_packet(self):
+ return self['fingerprint'][-8:].upper()
+
def _str_secret_key_packet(self):
- return self._str_generic_key_packet()
+ return self._str_generic_secret_key_packet()
def _str_secret_subkey_packet(self):
- return self._str_generic_key_packet()
-
- def _str_generic_key_packet(self):
- return self['fingerprint'][-8:].upper()
+ return self._str_generic_secret_key_packet()
+
+ def _str_generic_secret_key_packet(self):
+ lines = [self._str_generic_key_packet()]
+ for label, key in [
+ ('symmetric encryption',
+ 'symmetric-encryption-algorithm'),
+ ('s2k hash', 'string-to-key-hash-algorithm'),
+ ('s2k count', 'string-to-key-count'),
+ ('s2k salt', 'string-to-key-salt'),
+ ('IV', 'initial-vector'),
+ ]:
+ if key in self:
+ value = self[key]
+ if isinstance(value, bytes):
+ value = ' '.join('{:02x}'.format(byte) for byte in value)
+ lines.append(' {}: {}'.format(label, value))
+ return '\n'.join(lines)
def _str_signature_packet(self):
lines = [self['signature-type']]
raise NotImplementedError(
'cannot parse packet type {!r}'.format(self['type']))
method(data=packet)
+ self['raw'] = data[:offset]
return offset
def _parse_header(self, data):
offset += length
return (offset, value)
+ @classmethod
+ def _decode_string_to_key_count(cls, data):
+ r"""Decode RFC 4880's string-to-key count
+
+ >>> PGPPacket._decode_string_to_key_count(b'\x97'[0])
+ 753664
+ """
+ return (16 + (data & 15)) << ((data >> 4) + cls._string_to_key_expbias)
+
def _parse_string_to_key_specifier(self, data):
self['string-to-key-type'] = self._string_to_key_types[data[0]]
offset = 1
offset += 1
self['string-to-key-salt'] = data[offset: offset + 8]
offset += 8
- self['string-to-key-coded-count'] = data[offset]
+ self['string-to-key-count'] = self._decode_string_to_key_count(
+ data=data[offset])
offset += 1
else:
raise NotImplementedError(
self['symmetric-encryption-algorithm']))
self['initial-vector'] = data[offset: offset + block_size]
offset += block_size
+ ciphertext = data[offset:]
+ offset += len(ciphertext)
+ decrypted_data = self.decrypt_symmetric_encryption(data=ciphertext)
+ else:
+ decrypted_data = data[offset:key_end]
if string_to_key_usage in [0, 255]:
key_end = -2
+ elif string_to_key_usage == 254:
+ key_end = -20
else:
key_end = 0
- self['secret-key'] = data[offset:key_end]
+ secret_key = decrypted_data[:key_end]
+ secret_offset = 0
if key_end:
- self['secret-key-checksum'] = data[key_end:]
+ secret_key_checksum = decrypted_data[key_end:]
+ if key_end == -2:
+ calculated_checksum = sum(secret_key) % 65536
+ else:
+ checksum_hash = _hashlib.sha1()
+ checksum_hash.update(secret_key)
+ calculated_checksum = checksum_hash.digest()
+ if secret_key_checksum != calculated_checksum:
+ raise ValueError(
+ 'corrupt secret key (checksum {} != expected {})'.format(
+ secret_key_checksum, calculated_checksum))
+ if self['public-key-algorithm'].startswith('rsa '):
+ o, self['secret-exponent'] = self._parse_multiprecision_integer(
+ secret_key[secret_offset:])
+ secret_offset += o
+ o, self['secret-prime-p'] = self._parse_multiprecision_integer(
+ secret_key[secret_offset:])
+ secret_offset += o
+ o, self['secret-prime-q'] = self._parse_multiprecision_integer(
+ secret_key[secret_offset:])
+ secret_offset += o
+ o, self['secret-inverse-of-p-mod-q'] = (
+ self._parse_multiprecision_integer(
+ secret_key[secret_offset:]))
+ secret_offset += o
+ elif self['public-key-algorithm'].startswith('dsa '):
+ o, self['secret-exponent'] = self._parse_multiprecision_integer(
+ secret_key[secret_offset:])
+ secret_offset += o
+ elif self['public-key-algorithm'].startswith('elgamal '):
+ o, self['secret-exponent'] = self._parse_multiprecision_integer(
+ secret_key[secret_offset:])
+ secret_offset += o
+ else:
+ raise NotImplementedError(
+ 'algorithm-specific key fields for {}'.format(
+ self['public-key-algorithm']))
+ if secret_offset != len(secret_key):
+ raise ValueError(
+ ('parsed {} out of {} bytes of algorithm-specific key fields '
+ 'for {}').format(
+ secret_offset, len(secret_key),
+ self['public-key-algorithm']))
def _parse_signature_subpackets(self, data):
offset = 0
subpacket['features'].add('modification detection')
def _parse_embedded_signature_signature_subpacket(self, data, subpacket):
- subpacket['embedded'] = PGPPacket()
+ subpacket['embedded'] = PGPPacket(key=self.key)
subpacket['embedded']._parse_signature_packet(data=data)
def _parse_user_id_packet(self, data):
length_data,
])
+ @staticmethod
+ def _serialize_multiprecision_integer(integer):
+ r"""Serialize RFC 4880's multipricision integers
-def packets_from_bytes(data):
- offset = 0
- while offset < len(data):
- packet = PGPPacket()
- offset += packet.from_bytes(data=data[offset:])
- yield packet
+ >>> PGPPacket._serialize_multiprecision_integer(1)
+ b'\x00\x01\x01'
+ >>> PGPPacket._serialize_multiprecision_integer(511)
+ b'\x00\t\x01\xff'
+ """
+ bit_length = int(_math.log(integer, 2)) + 1
+ chunks = [
+ _struct.pack('>H', bit_length),
+ ]
+ while integer > 0:
+ chunks.insert(1, bytes([integer & 0xff]))
+ integer = integer >> 8
+ return b''.join(chunks)
+
+ @classmethod
+ def _encode_string_to_key_count(cls, count):
+ r"""Encode RFC 4880's string-to-key count
+
+ >>> PGPPacket._encode_string_to_key_count(753664)
+ b'\x97'
+ """
+ coded_count = 0
+ count = count >> cls._string_to_key_expbias
+ while not count & 1:
+ count = count >> 1
+ coded_count += 1 << 4
+ coded_count += count & 15
+ return bytes([coded_count])
+
+ def _serialize_string_to_key_specifier(self):
+ string_to_key_type = bytes([
+ self._reverse(
+ self._string_to_key_types, self['string-to-key-type']),
+ ])
+ chunks = [string_to_key_type]
+ if self['string-to-key-type'] == 'simple':
+ chunks.append(bytes([self._reverse(
+ self._hash_algorithms, self['string-to-key-hash-algorithm'])]))
+ elif self['string-to-key-type'] == 'salted':
+ chunks.append(bytes([self._reverse(
+ self._hash_algorithms, self['string-to-key-hash-algorithm'])]))
+ chunks.append(self['string-to-key-salt'])
+ elif self['string-to-key-type'] == 'iterated and salted':
+ chunks.append(bytes([self._reverse(
+ self._hash_algorithms, self['string-to-key-hash-algorithm'])]))
+ chunks.append(self['string-to-key-salt'])
+ chunks.append(self._encode_string_to_key_count(
+ count=self['string-to-key-count']))
+ else:
+ raise NotImplementedError(
+ 'string-to-key type {}'.format(self['string-to-key-type']))
+ return offset
+ return b''.join(chunks)
+
+ def _serialize_public_key_packet(self):
+ return self._serialize_generic_public_key_packet()
+
+ def _serialize_public_subkey_packet(self):
+ return self._serialize_generic_public_key_packet()
+
+ def _serialize_generic_public_key_packet(self):
+ key_version = bytes([self['key-version']])
+ chunks = [key_version]
+ if self['key-version'] != 4:
+ raise NotImplementedError(
+ 'public (sub)key packet version {}'.format(
+ self['key-version']))
+ chunks.append(_struct.pack('>I', self['creation-time']))
+ chunks.append(bytes([self._reverse(
+ self._public_key_algorithms, self['public-key-algorithm'])]))
+ if self['public-key-algorithm'].startswith('rsa '):
+ chunks.append(self._serialize_multiprecision_integer(
+ self['public-modulus']))
+ chunks.append(self._serialize_multiprecision_integer(
+ self['public-exponent']))
+ elif self['public-key-algorithm'].startswith('dsa '):
+ chunks.append(self._serialize_multiprecision_integer(
+ self['prime']))
+ chunks.append(self._serialize_multiprecision_integer(
+ self['group-order']))
+ chunks.append(self._serialize_multiprecision_integer(
+ self['group-generator']))
+ chunks.append(self._serialize_multiprecision_integer(
+ self['public-key']))
+ elif self['public-key-algorithm'].startswith('elgamal '):
+ chunks.append(self._serialize_multiprecision_integer(
+ self['prime']))
+ chunks.append(self._serialize_multiprecision_integer(
+ self['group-generator']))
+ chunks.append(self._serialize_multiprecision_integer(
+ self['public-key']))
+ else:
+ raise NotImplementedError(
+ 'algorithm-specific key fields for {}'.format(
+ self['public-key-algorithm']))
+ return b''.join(chunks)
+
+ def _string_to_key(self, string, key_size):
+ if key_size % 8:
+ raise ValueError(
+ '{}-bit key is not an integer number of bytes'.format(
+ key_size))
+ key_size_bytes = key_size // 8
+ hash_name = self._hashlib_name[
+ self['string-to-key-hash-algorithm']]
+ string_hash = _hashlib.new(hash_name)
+ hashes = _math.ceil(key_size_bytes / string_hash.digest_size)
+ key = b''
+ if self['string-to-key-type'] == 'simple':
+ update_bytes = string
+ elif self['string-to-key-type'] in [
+ 'salted',
+ 'iterated and salted',
+ ]:
+ update_bytes = self['string-to-key-salt'] + string
+ if self['string-to-key-type'] == 'iterated and salted':
+ count = self['string-to-key-count']
+ if count < len(update_bytes):
+ count = len(update_bytes)
+ else:
+ raise NotImplementedError(
+ 'key calculation for string-to-key type {}'.format(
+ self['string-to-key-type']))
+ for padding in range(hashes):
+ string_hash = _hashlib.new(hash_name)
+ string_hash.update(padding * b'\x00')
+ if self['string-to-key-type'] in [
+ 'simple',
+ 'salted',
+ ]:
+ string_hash.update(update_bytes)
+ elif self['string-to-key-type'] == 'iterated and salted':
+ remaining = count
+ while remaining > 0:
+ string_hash.update(update_bytes[:remaining])
+ remaining -= len(update_bytes)
+ key += string_hash.digest()
+ key = key[:key_size_bytes]
+ return key
+
+ def decrypt_symmetric_encryption(self, data):
+ """Decrypt OpenPGP's Cipher Feedback mode"""
+ algorithm = self['symmetric-encryption-algorithm']
+ module = self._crypto_module[algorithm]
+ key_size = self._key_size[algorithm]
+ segment_size_bits = self._cipher_block_size[algorithm]
+ if segment_size_bits % 8:
+ raise NotImplementedError(
+ ('{}-bit segment size for {} is not an integer number of bytes'
+ ).format(segment_size_bits, algorithm))
+ segment_size_bytes = segment_size_bits // 8
+ padding = segment_size_bytes - len(data) % segment_size_bytes
+ if padding:
+ data += b'\x00' * padding
+ if self.key and self.key._cache_passphrase and self.key._passphrase:
+ passphrase = self.key._passphrase
+ else:
+ passphrase = _getpass.getpass(
+ 'passphrase for {}: '.format(self['fingerprint'][-8:]))
+ passphrase = passphrase.encode('ascii')
+ if self.key and self.key._cache_passphrase:
+ self.key._passphrase = passphrase
+ key = self._string_to_key(string=passphrase, key_size=key_size)
+ cipher = module.new(
+ key=key,
+ mode=module.MODE_CFB,
+ IV=self['initial-vector'],
+ segment_size=segment_size_bits)
+ plaintext = cipher.decrypt(data)
+ if padding:
+ plaintext = plaintext[:-padding]
+ return plaintext
+
+ def check_roundtrip(self):
+ serialized = self.to_bytes()
+ source = self['raw']
+ if serialized != source:
+ if len(serialized) != len(source):
+ raise ValueError(
+ ('serialized {} is {} bytes long, '
+ 'but input is {} bytes long').format(
+ self['type'], len(serialized), len(source)))
+ chunk_size = 8
+ for i in range(0, len(source), 8):
+ in_chunk = source[i: i + chunk_size]
+ out_chunk = serialized[i: i + chunk_size]
+ if in_chunk != out_chunk:
+ raise ValueError(
+ ('serialized {} differs from input packet: '
+ 'at byte {}, {} != {}').format(
+ self['type'], i,
+ ' '.join('{:02x}'.format(byte) for byte in out_chunk),
+ ' '.join('{:02x}'.format(byte) for byte in in_chunk)))
class PGPKey (object):
[1]: http://tools.ietf.org/search/rfc4880#section-11.1
[2]: http://tools.ietf.org/search/rfc4880#section-11.2
"""
- def __init__(self, fingerprint):
+ def __init__(self, fingerprint, cache_passphrase=False):
self.fingerprint = fingerprint
+ self._cache_passphrase = cache_passphrase
+ self._passphrase = None
self.public_packets = None
self.secret_packets = None
key_export = _get_stdout(
['gpg', '--export', self.fingerprint])
self.public_packets = list(
- packets_from_bytes(data=key_export))
+ self._packets_from_bytes(data=key_export))
if self.public_packets[0]['type'] != 'public-key packet':
raise ValueError(
'{} does not start with a public-key packet'.format(
key_secret_export = _get_stdout(
['gpg', '--export-secret-keys', self.fingerprint])
self.secret_packets = list(
- packets_from_bytes(data=key_secret_export))
+ self._packets_from_bytes(data=key_secret_export))
if self.secret_packets[0]['type'] != 'secret-key packet':
raise ValueError(
'{} does not start with a secret-key packet'.format(
self.fingerprint))
+ for packet in self.public_packets + self.secret_packets:
+ packet.check_roundtrip()
+
+ def _packets_from_bytes(self, data):
+ offset = 0
+ while offset < len(data):
+ packet = PGPPacket(key=self)
+ offset += packet.from_bytes(data=data[offset:])
+ yield packet
def export_to_gpg(self):
raise NotImplemetedError('export to gpg')
pass
-def migrate(old_key, new_key):
+def migrate(old_key, new_key, cache_passphrase=False):
"""Add the old key and sub-keys to the new key
For example, to upgrade your master key, while preserving old
signatures you'd made. You will lose signature *on* your old key
though, since sub-keys can't be signed (I don't think).
"""
- old_key = PGPKey(fingerprint=old_key)
+ old_key = PGPKey(fingerprint=old_key, cache_passphrase=cache_passphrase)
old_key.import_from_gpg()
- new_key = PGPKey(fingerprint=new_key)
+ new_key = PGPKey(fingerprint=new_key, cache_passphrase=cache_passphrase)
new_key.import_from_gpg()
new_key.import_from_key(key=old_key)
import sys as _sys
old_key, new_key = _sys.argv[1:3]
- migrate(old_key=old_key, new_key=new_key)
+ migrate(old_key=old_key, new_key=new_key, cache_passphrase=True)
projects / gpg-migrate.git / blobdiff