gpg: minor renames and code refactoring
This commit is contained in:
@@ -20,15 +20,15 @@ def original_data(filename):
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def verify(pubkey, sig_file):
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d = open(sig_file, 'rb')
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if d.name.endswith('.asc'):
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lines = d.readlines()[3:-1]
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"""Verify correctness of public key and signature."""
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stream = open(sig_file, 'rb')
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if stream.name.endswith('.asc'):
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lines = stream.readlines()[3:-1]
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data = base64.b64decode(''.join(lines))
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payload, checksum = data[:-3], data[-3:]
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assert util.crc24(payload) == checksum
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d = io.BytesIO(payload)
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parser = decode.Parser(decode.Reader(d), original_data(sig_file))
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stream = io.BytesIO(payload)
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parser = decode.Parser(util.Reader(stream), original_data(sig_file))
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signature, = list(parser)
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decode.verify_digest(pubkey=pubkey, digest=signature['digest'],
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signature=signature['sig'], label='GPG signature')
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@@ -1,78 +1,24 @@
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"""Decoders for GPG v2 data structures."""
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import binascii
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import contextlib
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import hashlib
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import io
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import logging
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import struct
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import subprocess
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import ecdsa
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import ed25519
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from trezor_agent.util import num2bytes
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from .. import util
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log = logging.getLogger(__name__)
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def bit(value, i):
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"""Extract the i-th bit out of value."""
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return 1 if value & (1 << i) else 0
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def low_bits(value, n):
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"""Extract the lowest n bits out of value."""
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return value & ((1 << n) - 1)
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def readfmt(stream, fmt):
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"""Read and unpack an object from stream, using a struct format string."""
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size = struct.calcsize(fmt)
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blob = stream.read(size)
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return struct.unpack(fmt, blob)
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class Reader(object):
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"""Read basic type objects out of given stream."""
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def __init__(self, stream):
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"""Create a non-capturing reader."""
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self.s = stream
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self._captured = None
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def readfmt(self, fmt):
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"""Read a specified object, using a struct format string."""
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size = struct.calcsize(fmt)
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blob = self.read(size)
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obj, = struct.unpack(fmt, blob)
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return obj
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def read(self, size=None):
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"""Read `size` bytes from stream."""
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blob = self.s.read(size)
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if size is not None and len(blob) < size:
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raise EOFError
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if self._captured:
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self._captured.write(blob)
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return blob
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@contextlib.contextmanager
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def capture(self, stream):
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"""Capture all data read during this context."""
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self._captured = stream
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try:
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yield
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finally:
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self._captured = None
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length_types = {0: '>B', 1: '>H', 2: '>L'}
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def parse_subpackets(s):
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"""See https://tools.ietf.org/html/rfc4880#section-5.2.3.1 for details."""
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subpackets = []
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total_size = s.readfmt('>H')
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data = s.read(total_size)
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s = Reader(io.BytesIO(data))
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s = util.Reader(io.BytesIO(data))
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while True:
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try:
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@@ -92,23 +38,8 @@ def parse_mpi(s):
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return sum(v << (8 * i) for i, v in enumerate(reversed(blob)))
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def split_bits(value, *bits):
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"""
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Split integer value into list of ints, according to `bits` list.
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For example, split_bits(0x1234, 4, 8, 4) == [0x1, 0x23, 0x4]
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"""
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result = []
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for b in reversed(bits):
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mask = (1 << b) - 1
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result.append(value & mask)
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value = value >> b
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assert value == 0
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return reversed(result)
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def _parse_nist256p1_verifier(mpi):
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prefix, x, y = split_bits(mpi, 4, 256, 256)
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prefix, x, y = util.split_bits(mpi, 4, 256, 256)
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assert prefix == 4
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point = ecdsa.ellipticcurve.Point(curve=ecdsa.NIST256p.curve,
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x=x, y=y)
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@@ -124,12 +55,12 @@ def _parse_nist256p1_verifier(mpi):
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def _parse_ed25519_verifier(mpi):
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prefix, value = split_bits(mpi, 8, 256)
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prefix, value = util.split_bits(mpi, 8, 256)
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assert prefix == 0x40
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vk = ed25519.VerifyingKey(num2bytes(value, size=32))
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vk = ed25519.VerifyingKey(util.num2bytes(value, size=32))
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def _ed25519_verify(signature, digest):
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sig = b''.join(num2bytes(val, size=32)
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sig = b''.join(util.num2bytes(val, size=32)
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for val in signature)
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vk.verify(sig, digest)
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return _ed25519_verify
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@@ -229,7 +160,7 @@ class Parser(object):
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data_to_hash = (b'\x99' + struct.pack('>H', len(packet_data)) +
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packet_data)
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p['key_id'] = hashlib.sha1(data_to_hash).digest()[-8:]
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log.debug('key ID: %s', binascii.hexlify(p['key_id']).decode('ascii'))
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log.debug('key ID: %s', util.hexlify(p['key_id']))
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self.to_hash.write(data_to_hash)
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return p
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@@ -249,20 +180,20 @@ class Parser(object):
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raise StopIteration
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log.debug('prefix byte: %02x', value)
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assert bit(value, 7) == 1
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assert bit(value, 6) == 0 # new format not supported yet
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assert util.bit(value, 7) == 1
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assert util.bit(value, 6) == 0 # new format not supported yet
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tag = low_bits(value, 6)
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length_type = low_bits(tag, 2)
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tag = util.low_bits(value, 6)
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length_type = util.low_bits(tag, 2)
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tag = tag >> 2
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fmt = length_types[length_type]
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fmt = {0: '>B', 1: '>H', 2: '>L'}[length_type]
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log.debug('length_type: %s', fmt)
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packet_size = self.stream.readfmt(fmt)
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log.debug('packet length: %d', packet_size)
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packet_data = self.stream.read(packet_size)
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packet_type = self.packet_types.get(tag)
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if packet_type:
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p = packet_type(Reader(io.BytesIO(packet_data)))
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p = packet_type(util.Reader(io.BytesIO(packet_data)))
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else:
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raise ValueError('Unknown packet type: {}'.format(packet_type))
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p['tag'] = tag
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@@ -274,7 +205,7 @@ class Parser(object):
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def load_public_key(stream):
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"""Parse and validate GPG public key from an input stream."""
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parser = Parser(Reader(stream))
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parser = Parser(util.Reader(stream))
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pubkey, userid, signature = list(parser)
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log.debug('loaded public key "%s"', userid['value'])
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verify_digest(pubkey=pubkey, digest=signature['digest'],
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@@ -282,6 +213,16 @@ def load_public_key(stream):
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return pubkey
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def load_from_gpg(user_id):
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"""Load existing GPG public key for `user_id` from local keyring."""
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pubkey_bytes = subprocess.check_output(['gpg2', '--export', user_id])
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if pubkey_bytes:
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return load_public_key(io.BytesIO(pubkey_bytes))
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else:
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log.error('could not find public key %r in local GPG keyring', user_id)
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raise KeyError(user_id)
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def verify_digest(pubkey, digest, signature, label):
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"""Verify a digest signature from a specified public key."""
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verifier = pubkey['verifier']
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243
trezor_agent/gpg/encode.py
Normal file
243
trezor_agent/gpg/encode.py
Normal file
@@ -0,0 +1,243 @@
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"""Create GPG ECDSA signatures and public keys using TREZOR device."""
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import base64
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import hashlib
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import logging
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import struct
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import time
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from .. import client, factory, formats, util
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log = logging.getLogger(__name__)
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def packet(tag, blob):
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"""Create small GPG packet."""
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assert len(blob) < 256
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length_type = 0 # : 1 byte for length
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leading_byte = 0x80 | (tag << 2) | (length_type)
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return struct.pack('>B', leading_byte) + util.prefix_len('>B', blob)
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def subpacket(subpacket_type, fmt, *values):
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"""Create GPG subpacket."""
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blob = struct.pack(fmt, *values) if values else fmt
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return struct.pack('>B', subpacket_type) + blob
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def subpacket_long(subpacket_type, value):
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"""Create GPG subpacket with 32-bit unsigned integer."""
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return subpacket(subpacket_type, '>L', value)
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def subpacket_time(value):
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"""Create GPG subpacket with time in seconds (since Epoch)."""
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return subpacket_long(2, value)
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def subpacket_byte(subpacket_type, value):
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"""Create GPG subpacket with 8-bit unsigned integer."""
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return subpacket(subpacket_type, '>B', value)
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def subpackets(*items):
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"""Serialize several GPG subpackets."""
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prefixed = [util.prefix_len('>B', item) for item in items]
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return util.prefix_len('>H', b''.join(prefixed))
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def mpi(value):
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"""Serialize multipresicion integer using GPG format."""
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bits = value.bit_length()
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data_size = (bits + 7) // 8
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data_bytes = [0] * data_size
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for i in range(data_size):
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data_bytes[i] = value & 0xFF
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value = value >> 8
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data_bytes.reverse()
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return struct.pack('>H', bits) + bytearray(data_bytes)
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def _dump_nist256(vk):
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return mpi((4 << 512) |
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(vk.pubkey.point.x() << 256) |
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(vk.pubkey.point.y()))
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def _dump_ed25519(vk):
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return mpi((0x40 << 256) |
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util.bytes2num(vk.to_bytes()))
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SUPPORTED_CURVES = {
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formats.CURVE_NIST256: {
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# https://tools.ietf.org/html/rfc6637#section-11
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'oid': b'\x2A\x86\x48\xCE\x3D\x03\x01\x07',
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'algo_id': 19,
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'dump': _dump_nist256
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},
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formats.CURVE_ED25519: {
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'oid': b'\x2B\x06\x01\x04\x01\xDA\x47\x0F\x01',
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'algo_id': 22,
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'dump': _dump_ed25519
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}
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}
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def _find_curve_by_algo_id(algo_id):
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curve_name, = [name for name, info in SUPPORTED_CURVES.items()
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if info['algo_id'] == algo_id]
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return curve_name
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class Signer(object):
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"""Performs GPG operations with the TREZOR."""
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def __init__(self, user_id, created, curve_name):
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"""Construct and loads a public key from the device."""
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self.user_id = user_id
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assert curve_name in formats.SUPPORTED_CURVES
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self.curve_name = curve_name
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self.client_wrapper = factory.load()
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self.identity = self.client_wrapper.identity_type()
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self.identity.proto = 'gpg'
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self.identity.host = user_id
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addr = client.get_address(self.identity)
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public_node = self.client_wrapper.connection.get_public_node(
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n=addr, ecdsa_curve_name=self.curve_name)
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self.verifying_key = formats.decompress_pubkey(
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pubkey=public_node.node.public_key,
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curve_name=self.curve_name)
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self.created = int(created)
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log.info('%s GPG public key %s created at %s', self.curve_name,
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self.hex_short_key_id(), util.time_format(self.created))
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@classmethod
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def from_public_key(cls, pubkey, user_id):
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"""
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Create from an existing GPG public key.
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`pubkey` should be loaded via `load_from_gpg(user_id)`
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from the local GPG keyring.
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"""
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s = Signer(user_id=user_id,
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created=pubkey['created'],
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curve_name=_find_curve_by_algo_id(pubkey['algo']))
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assert s.key_id() == pubkey['key_id']
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return s
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def _pubkey_data(self):
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curve_info = SUPPORTED_CURVES[self.curve_name]
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header = struct.pack('>BLB',
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4, # version
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self.created, # creation
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curve_info['algo_id'])
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oid = util.prefix_len('>B', curve_info['oid'])
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blob = curve_info['dump'](self.verifying_key)
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return header + oid + blob
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def _pubkey_data_to_hash(self):
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return b'\x99' + util.prefix_len('>H', self._pubkey_data())
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def _fingerprint(self):
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return hashlib.sha1(self._pubkey_data_to_hash()).digest()
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def key_id(self):
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"""Short (8 byte) GPG key ID."""
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return self._fingerprint()[-8:]
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def hex_short_key_id(self):
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"""Short (8 hexadecimal digits) GPG key ID."""
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return util.hexlify(self.key_id()[-4:])
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def close(self):
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"""Close connection and turn off the screen of the device."""
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self.client_wrapper.connection.clear_session()
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self.client_wrapper.connection.close()
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def export(self):
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"""Export GPG public key, ready for "gpg2 --import"."""
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pubkey_packet = packet(tag=6, blob=self._pubkey_data())
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user_id_packet = packet(tag=13, blob=self.user_id)
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data_to_sign = (self._pubkey_data_to_hash() +
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user_id_packet[:1] +
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util.prefix_len('>L', self.user_id))
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log.info('signing public key "%s"', self.user_id)
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hashed_subpackets = [
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subpacket_time(self.created), # signature creaion time
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subpacket_byte(0x1B, 1 | 2), # key flags (certify & sign)
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subpacket_byte(0x15, 8), # preferred hash (SHA256)
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subpacket_byte(0x16, 0), # preferred compression (none)
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subpacket_byte(0x17, 0x80)] # key server prefs (no-modify)
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signature = self._make_signature(visual=self.hex_short_key_id(),
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data_to_sign=data_to_sign,
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sig_type=0x13, # user id & public key
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hashed_subpackets=hashed_subpackets)
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sign_packet = packet(tag=2, blob=signature)
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return pubkey_packet + user_id_packet + sign_packet
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def sign(self, msg, sign_time=None):
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"""Sign GPG message at specified time."""
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if sign_time is None:
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sign_time = int(time.time())
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log.info('signing %d byte message at %s',
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len(msg), util.time_format(sign_time))
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hashed_subpackets = [subpacket_time(sign_time)]
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blob = self._make_signature(
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visual=self.hex_short_key_id(),
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data_to_sign=msg, hashed_subpackets=hashed_subpackets)
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return packet(tag=2, blob=blob)
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def _make_signature(self, visual, data_to_sign,
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hashed_subpackets, sig_type=0):
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curve_info = SUPPORTED_CURVES[self.curve_name]
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header = struct.pack('>BBBB',
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4, # version
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sig_type, # rfc4880 (section-5.2.1)
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curve_info['algo_id'],
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8) # hash_alg (SHA256)
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hashed = subpackets(*hashed_subpackets)
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unhashed = subpackets(
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subpacket(16, self.key_id()) # issuer key id
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)
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tail = b'\x04\xff' + struct.pack('>L', len(header) + len(hashed))
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data_to_hash = data_to_sign + header + hashed + tail
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log.debug('hashing %d bytes', len(data_to_hash))
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digest = hashlib.sha256(data_to_hash).digest()
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result = self.client_wrapper.connection.sign_identity(
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identity=self.identity,
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challenge_hidden=digest,
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challenge_visual=visual,
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ecdsa_curve_name=self.curve_name)
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assert result.signature[:1] == b'\x00'
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sig = result.signature[1:]
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sig = mpi(util.bytes2num(sig[:32])) + mpi(util.bytes2num(sig[32:]))
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return (header + hashed + unhashed +
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digest[:2] + # used for decoder's sanity check
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sig) # actual ECDSA signature
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def _split_lines(body, size):
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lines = []
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for i in range(0, len(body), size):
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lines.append(body[i:i+size] + '\n')
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return ''.join(lines)
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def armor(blob, type_str):
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"""See https://tools.ietf.org/html/rfc4880#section-6 for details."""
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head = '-----BEGIN PGP {}-----\nVersion: GnuPG v2\n\n'.format(type_str)
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body = base64.b64encode(blob)
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checksum = base64.b64encode(util.crc24(blob))
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tail = '-----END PGP {}-----\n'.format(type_str)
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return head + _split_lines(body, 64) + '=' + checksum + '\n' + tail
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@@ -4,7 +4,7 @@ import logging
|
||||
import subprocess as sp
|
||||
import sys
|
||||
|
||||
from . import signer
|
||||
from . import decode, encode
|
||||
|
||||
log = logging.getLogger(__name__)
|
||||
|
||||
@@ -22,12 +22,12 @@ def main():
|
||||
command = args[0]
|
||||
user_id = ' '.join(args[1:])
|
||||
assert command == '-bsau' # --detach-sign --sign --armor --local-user
|
||||
pubkey = signer.load_from_gpg(user_id)
|
||||
s = signer.Signer.from_public_key(user_id=user_id, pubkey=pubkey)
|
||||
pubkey = decode.load_from_gpg(user_id)
|
||||
s = encode.Signer.from_public_key(user_id=user_id, pubkey=pubkey)
|
||||
|
||||
data = sys.stdin.read()
|
||||
sig = s.sign(data)
|
||||
sig = signer.armor(sig, 'SIGNATURE')
|
||||
sig = encode.armor(sig, 'SIGNATURE')
|
||||
sys.stdout.write(sig)
|
||||
s.close()
|
||||
|
||||
|
||||
@@ -1,278 +1,14 @@
|
||||
#!/usr/bin/env python
|
||||
"""Create GPG ECDSA signatures and public keys using TREZOR device."""
|
||||
"""Create signatures and export public keys for GPG using TREZOR."""
|
||||
import argparse
|
||||
import base64
|
||||
import binascii
|
||||
import hashlib
|
||||
import io
|
||||
import logging
|
||||
import struct
|
||||
import subprocess
|
||||
import time
|
||||
|
||||
from . import decode, check
|
||||
from .. import client, factory, formats, util
|
||||
from . import check, decode, encode
|
||||
|
||||
log = logging.getLogger(__name__)
|
||||
|
||||
|
||||
def prefix_len(fmt, blob):
|
||||
"""Prefix `blob` with its size, serialized using `fmt` format."""
|
||||
return struct.pack(fmt, len(blob)) + blob
|
||||
|
||||
|
||||
def packet(tag, blob):
|
||||
"""Create small GPG packet."""
|
||||
assert len(blob) < 256
|
||||
length_type = 0 # : 1 byte for length
|
||||
leading_byte = 0x80 | (tag << 2) | (length_type)
|
||||
return struct.pack('>B', leading_byte) + prefix_len('>B', blob)
|
||||
|
||||
|
||||
def subpacket(subpacket_type, fmt, *values):
|
||||
"""Create GPG subpacket."""
|
||||
blob = struct.pack(fmt, *values) if values else fmt
|
||||
return struct.pack('>B', subpacket_type) + blob
|
||||
|
||||
|
||||
def subpacket_long(subpacket_type, value):
|
||||
"""Create GPG subpacket with 32-bit unsigned integer."""
|
||||
return subpacket(subpacket_type, '>L', value)
|
||||
|
||||
|
||||
def subpacket_time(value):
|
||||
"""Create GPG subpacket with time in seconds (since Epoch)."""
|
||||
return subpacket_long(2, value)
|
||||
|
||||
|
||||
def subpacket_byte(subpacket_type, value):
|
||||
"""Create GPG subpacket with 8-bit unsigned integer."""
|
||||
return subpacket(subpacket_type, '>B', value)
|
||||
|
||||
|
||||
def subpackets(*items):
|
||||
"""Serialize several GPG subpackets."""
|
||||
prefixed = [prefix_len('>B', item) for item in items]
|
||||
return prefix_len('>H', b''.join(prefixed))
|
||||
|
||||
|
||||
def mpi(value):
|
||||
"""Serialize multipresicion integer using GPG format."""
|
||||
bits = value.bit_length()
|
||||
data_size = (bits + 7) // 8
|
||||
data_bytes = [0] * data_size
|
||||
for i in range(data_size):
|
||||
data_bytes[i] = value & 0xFF
|
||||
value = value >> 8
|
||||
|
||||
data_bytes.reverse()
|
||||
return struct.pack('>H', bits) + bytearray(data_bytes)
|
||||
|
||||
|
||||
def time_format(t):
|
||||
"""Utility for consistent time formatting."""
|
||||
return time.strftime('%Y-%m-%d %H:%M:%S', time.localtime(t))
|
||||
|
||||
|
||||
def hexlify(blob):
|
||||
"""Utility for consistent hexadecimal formatting."""
|
||||
return binascii.hexlify(blob).decode('ascii').upper()
|
||||
|
||||
|
||||
def _dump_nist256(vk):
|
||||
return mpi((4 << 512) |
|
||||
(vk.pubkey.point.x() << 256) |
|
||||
(vk.pubkey.point.y()))
|
||||
|
||||
|
||||
def _dump_ed25519(vk):
|
||||
return mpi((0x40 << 256) |
|
||||
util.bytes2num(vk.to_bytes()))
|
||||
|
||||
|
||||
SUPPORTED_CURVES = {
|
||||
formats.CURVE_NIST256: {
|
||||
# https://tools.ietf.org/html/rfc6637#section-11
|
||||
'oid': b'\x2A\x86\x48\xCE\x3D\x03\x01\x07',
|
||||
'algo_id': 19,
|
||||
'dump': _dump_nist256
|
||||
},
|
||||
formats.CURVE_ED25519: {
|
||||
'oid': b'\x2B\x06\x01\x04\x01\xDA\x47\x0F\x01',
|
||||
'algo_id': 22,
|
||||
'dump': _dump_ed25519
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
def _find_curve_by_algo_id(algo_id):
|
||||
curve_name, = [name for name, info in SUPPORTED_CURVES.items()
|
||||
if info['algo_id'] == algo_id]
|
||||
return curve_name
|
||||
|
||||
|
||||
class Signer(object):
|
||||
"""Performs GPG operations with the TREZOR."""
|
||||
|
||||
def __init__(self, user_id, created, curve_name):
|
||||
"""Construct and loads a public key from the device."""
|
||||
self.user_id = user_id
|
||||
assert curve_name in formats.SUPPORTED_CURVES
|
||||
self.curve_name = curve_name
|
||||
self.client_wrapper = factory.load()
|
||||
|
||||
self.identity = self.client_wrapper.identity_type()
|
||||
self.identity.proto = 'gpg'
|
||||
self.identity.host = user_id
|
||||
|
||||
addr = client.get_address(self.identity)
|
||||
public_node = self.client_wrapper.connection.get_public_node(
|
||||
n=addr, ecdsa_curve_name=self.curve_name)
|
||||
|
||||
self.verifying_key = formats.decompress_pubkey(
|
||||
pubkey=public_node.node.public_key,
|
||||
curve_name=self.curve_name)
|
||||
|
||||
self.created = int(created)
|
||||
log.info('%s GPG public key %s created at %s', self.curve_name,
|
||||
self.hex_short_key_id(), time_format(self.created))
|
||||
|
||||
@classmethod
|
||||
def from_public_key(cls, pubkey, user_id):
|
||||
"""
|
||||
Create from an existing GPG public key.
|
||||
|
||||
`pubkey` should be loaded via `load_from_gpg(user_id)`
|
||||
from the local GPG keyring.
|
||||
"""
|
||||
s = Signer(user_id=user_id,
|
||||
created=pubkey['created'],
|
||||
curve_name=_find_curve_by_algo_id(pubkey['algo']))
|
||||
assert s.key_id() == pubkey['key_id']
|
||||
return s
|
||||
|
||||
def _pubkey_data(self):
|
||||
curve_info = SUPPORTED_CURVES[self.curve_name]
|
||||
header = struct.pack('>BLB',
|
||||
4, # version
|
||||
self.created, # creation
|
||||
curve_info['algo_id'])
|
||||
oid = prefix_len('>B', curve_info['oid'])
|
||||
blob = curve_info['dump'](self.verifying_key)
|
||||
return header + oid + blob
|
||||
|
||||
def _pubkey_data_to_hash(self):
|
||||
return b'\x99' + prefix_len('>H', self._pubkey_data())
|
||||
|
||||
def _fingerprint(self):
|
||||
return hashlib.sha1(self._pubkey_data_to_hash()).digest()
|
||||
|
||||
def key_id(self):
|
||||
"""Short (8 byte) GPG key ID."""
|
||||
return self._fingerprint()[-8:]
|
||||
|
||||
def hex_short_key_id(self):
|
||||
"""Short (8 hexadecimal digits) GPG key ID."""
|
||||
return hexlify(self.key_id()[-4:])
|
||||
|
||||
def close(self):
|
||||
"""Close connection and turn off the screen of the device."""
|
||||
self.client_wrapper.connection.clear_session()
|
||||
self.client_wrapper.connection.close()
|
||||
|
||||
def export(self):
|
||||
"""Export GPG public key, ready for "gpg2 --import"."""
|
||||
pubkey_packet = packet(tag=6, blob=self._pubkey_data())
|
||||
user_id_packet = packet(tag=13, blob=self.user_id)
|
||||
|
||||
user_id_to_hash = user_id_packet[:1] + prefix_len('>L', self.user_id)
|
||||
data_to_sign = self._pubkey_data_to_hash() + user_id_to_hash
|
||||
log.info('signing public key "%s"', self.user_id)
|
||||
hashed_subpackets = [
|
||||
subpacket_time(self.created), # signature creaion time
|
||||
subpacket_byte(0x1B, 1 | 2), # key flags (certify & sign)
|
||||
subpacket_byte(0x15, 8), # preferred hash (SHA256)
|
||||
subpacket_byte(0x16, 0), # preferred compression (none)
|
||||
subpacket_byte(0x17, 0x80)] # key server prefs (no-modify)
|
||||
signature = self._make_signature(visual=self.hex_short_key_id(),
|
||||
data_to_sign=data_to_sign,
|
||||
sig_type=0x13, # user id & public key
|
||||
hashed_subpackets=hashed_subpackets)
|
||||
|
||||
sign_packet = packet(tag=2, blob=signature)
|
||||
return pubkey_packet + user_id_packet + sign_packet
|
||||
|
||||
def sign(self, msg, sign_time=None):
|
||||
"""Sign GPG message at specified time."""
|
||||
if sign_time is None:
|
||||
sign_time = int(time.time())
|
||||
|
||||
log.info('signing %d byte message at %s',
|
||||
len(msg), time_format(sign_time))
|
||||
hashed_subpackets = [subpacket_time(sign_time)]
|
||||
blob = self._make_signature(
|
||||
visual=self.hex_short_key_id(),
|
||||
data_to_sign=msg, hashed_subpackets=hashed_subpackets)
|
||||
return packet(tag=2, blob=blob)
|
||||
|
||||
def _make_signature(self, visual, data_to_sign,
|
||||
hashed_subpackets, sig_type=0):
|
||||
curve_info = SUPPORTED_CURVES[self.curve_name]
|
||||
header = struct.pack('>BBBB',
|
||||
4, # version
|
||||
sig_type, # rfc4880 (section-5.2.1)
|
||||
curve_info['algo_id'],
|
||||
8) # hash_alg (SHA256)
|
||||
hashed = subpackets(*hashed_subpackets)
|
||||
unhashed = subpackets(
|
||||
subpacket(16, self.key_id()) # issuer key id
|
||||
)
|
||||
tail = b'\x04\xff' + struct.pack('>L', len(header) + len(hashed))
|
||||
data_to_hash = data_to_sign + header + hashed + tail
|
||||
|
||||
log.debug('hashing %d bytes', len(data_to_hash))
|
||||
digest = hashlib.sha256(data_to_hash).digest()
|
||||
|
||||
result = self.client_wrapper.connection.sign_identity(
|
||||
identity=self.identity,
|
||||
challenge_hidden=digest,
|
||||
challenge_visual=visual,
|
||||
ecdsa_curve_name=self.curve_name)
|
||||
assert result.signature[:1] == b'\x00'
|
||||
sig = result.signature[1:]
|
||||
sig = mpi(util.bytes2num(sig[:32])) + mpi(util.bytes2num(sig[32:]))
|
||||
|
||||
return (header + hashed + unhashed +
|
||||
digest[:2] + # used for decoder's sanity check
|
||||
sig) # actual ECDSA signature
|
||||
|
||||
|
||||
def _split_lines(body, size):
|
||||
lines = []
|
||||
for i in range(0, len(body), size):
|
||||
lines.append(body[i:i+size] + '\n')
|
||||
return ''.join(lines)
|
||||
|
||||
|
||||
def armor(blob, type_str):
|
||||
"""See https://tools.ietf.org/html/rfc4880#section-6 for details."""
|
||||
head = '-----BEGIN PGP {}-----\nVersion: GnuPG v2\n\n'.format(type_str)
|
||||
body = base64.b64encode(blob)
|
||||
checksum = base64.b64encode(util.crc24(blob))
|
||||
tail = '-----END PGP {}-----\n'.format(type_str)
|
||||
return head + _split_lines(body, 64) + '=' + checksum + '\n' + tail
|
||||
|
||||
|
||||
def load_from_gpg(user_id):
|
||||
"""Load existing GPG public key for `user_id` from local keyring."""
|
||||
pubkey_bytes = subprocess.check_output(['gpg2', '--export', user_id])
|
||||
if pubkey_bytes:
|
||||
return decode.load_public_key(io.BytesIO(pubkey_bytes))
|
||||
else:
|
||||
log.error('could not find public key %r in local GPG keyring', user_id)
|
||||
raise KeyError(user_id)
|
||||
|
||||
|
||||
def main():
|
||||
"""Main function."""
|
||||
p = argparse.ArgumentParser()
|
||||
@@ -288,23 +24,23 @@ def main():
|
||||
format='%(asctime)s %(levelname)-10s %(message)s')
|
||||
user_id = args.user_id.encode('ascii')
|
||||
if not args.filename:
|
||||
s = Signer(user_id=user_id, created=args.time,
|
||||
curve_name=args.ecdsa_curve)
|
||||
s = encode.Signer(user_id=user_id, created=args.time,
|
||||
curve_name=args.ecdsa_curve)
|
||||
pubkey = s.export()
|
||||
ext = '.pub'
|
||||
if args.armor:
|
||||
pubkey = armor(pubkey, 'PUBLIC KEY BLOCK')
|
||||
pubkey = encode.armor(pubkey, 'PUBLIC KEY BLOCK')
|
||||
ext = '.asc'
|
||||
filename = s.hex_short_key_id() + ext
|
||||
open(filename, 'wb').write(pubkey)
|
||||
log.info('import to local keyring using "gpg2 --import %s"', filename)
|
||||
else:
|
||||
pubkey = load_from_gpg(user_id)
|
||||
s = Signer.from_public_key(pubkey=pubkey, user_id=user_id)
|
||||
pubkey = decode.load_from_gpg(user_id)
|
||||
s = encode.Signer.from_public_key(pubkey=pubkey, user_id=user_id)
|
||||
data = open(args.filename, 'rb').read()
|
||||
sig, ext = s.sign(data), '.sig'
|
||||
if args.armor:
|
||||
sig = armor(sig, 'SIGNATURE')
|
||||
sig = encode.armor(sig, 'SIGNATURE')
|
||||
ext = '.asc'
|
||||
filename = args.filename + ext
|
||||
open(filename, 'wb').write(sig)
|
||||
|
||||
@@ -1,6 +1,9 @@
|
||||
"""Various I/O and serialization utilities."""
|
||||
import binascii
|
||||
import contextlib
|
||||
import io
|
||||
import struct
|
||||
import time
|
||||
|
||||
|
||||
def send(conn, data):
|
||||
@@ -93,3 +96,84 @@ def crc24(blob):
|
||||
crc_bytes = struct.pack('>L', crc)
|
||||
assert crc_bytes[0] == b'\x00'
|
||||
return crc_bytes[1:]
|
||||
|
||||
|
||||
def bit(value, i):
|
||||
"""Extract the i-th bit out of value."""
|
||||
return 1 if value & (1 << i) else 0
|
||||
|
||||
|
||||
def low_bits(value, n):
|
||||
"""Extract the lowest n bits out of value."""
|
||||
return value & ((1 << n) - 1)
|
||||
|
||||
|
||||
def split_bits(value, *bits):
|
||||
"""
|
||||
Split integer value into list of ints, according to `bits` list.
|
||||
|
||||
For example, split_bits(0x1234, 4, 8, 4) == [0x1, 0x23, 0x4]
|
||||
"""
|
||||
result = []
|
||||
for b in reversed(bits):
|
||||
mask = (1 << b) - 1
|
||||
result.append(value & mask)
|
||||
value = value >> b
|
||||
assert value == 0
|
||||
return reversed(result)
|
||||
|
||||
|
||||
def readfmt(stream, fmt):
|
||||
"""Read and unpack an object from stream, using a struct format string."""
|
||||
size = struct.calcsize(fmt)
|
||||
blob = stream.read(size)
|
||||
return struct.unpack(fmt, blob)
|
||||
|
||||
|
||||
def prefix_len(fmt, blob):
|
||||
"""Prefix `blob` with its size, serialized using `fmt` format."""
|
||||
return struct.pack(fmt, len(blob)) + blob
|
||||
|
||||
|
||||
def time_format(t):
|
||||
"""Utility for consistent time formatting."""
|
||||
return time.strftime('%Y-%m-%d %H:%M:%S', time.localtime(t))
|
||||
|
||||
|
||||
def hexlify(blob):
|
||||
"""Utility for consistent hexadecimal formatting."""
|
||||
return binascii.hexlify(blob).decode('ascii').upper()
|
||||
|
||||
|
||||
class Reader(object):
|
||||
"""Read basic type objects out of given stream."""
|
||||
|
||||
def __init__(self, stream):
|
||||
"""Create a non-capturing reader."""
|
||||
self.s = stream
|
||||
self._captured = None
|
||||
|
||||
def readfmt(self, fmt):
|
||||
"""Read a specified object, using a struct format string."""
|
||||
size = struct.calcsize(fmt)
|
||||
blob = self.read(size)
|
||||
obj, = struct.unpack(fmt, blob)
|
||||
return obj
|
||||
|
||||
def read(self, size=None):
|
||||
"""Read `size` bytes from stream."""
|
||||
blob = self.s.read(size)
|
||||
if size is not None and len(blob) < size:
|
||||
raise EOFError
|
||||
if self._captured:
|
||||
self._captured.write(blob)
|
||||
return blob
|
||||
|
||||
@contextlib.contextmanager
|
||||
def capture(self, stream):
|
||||
"""Capture all data read during this context."""
|
||||
self._captured = stream
|
||||
try:
|
||||
yield
|
||||
finally:
|
||||
self._captured = None
|
||||
|
||||
Reference in New Issue
Block a user