Split the package into a shared library and separate per-device packages

libagent/gpg/__init__.py

@@ -0,0 +1,145 @@
+"""
+TREZOR support for ECDSA GPG signatures.
+
+See these links for more details:
+ - https://www.gnupg.org/faq/whats-new-in-2.1.html
+ - https://tools.ietf.org/html/rfc4880
+ - https://tools.ietf.org/html/rfc6637
+ - https://tools.ietf.org/html/draft-irtf-cfrg-eddsa-05
+"""
+
+import argparse
+import contextlib
+import logging
+import os
+import sys
+import time
+
+import semver
+
+from . import agent, client, encode, keyring, protocol
+from .. import device, formats, server, util
+
+log = logging.getLogger(__name__)
+
+
+def export_public_key(device_type, args):
+    """Generate a new pubkey for a new/existing GPG identity."""
+    log.warning('NOTE: in order to re-generate the exact same GPG key later, '
+                'run this command with "--time=%d" commandline flag (to set '
+                'the timestamp of the GPG key manually).', args.time)
+    c = client.Client(user_id=args.user_id, curve_name=args.ecdsa_curve,
+                      device_type=device_type)
+    verifying_key = c.pubkey(ecdh=False)
+    decryption_key = c.pubkey(ecdh=True)
+
+    if args.subkey:  # add as subkey
+        log.info('adding %s GPG subkey for "%s" to existing key',
+                 args.ecdsa_curve, args.user_id)
+        # subkey for signing
+        signing_key = protocol.PublicKey(
+            curve_name=args.ecdsa_curve, created=args.time,
+            verifying_key=verifying_key, ecdh=False)
+        # subkey for encryption
+        encryption_key = protocol.PublicKey(
+            curve_name=formats.get_ecdh_curve_name(args.ecdsa_curve),
+            created=args.time, verifying_key=decryption_key, ecdh=True)
+        primary_bytes = keyring.export_public_key(args.user_id)
+        result = encode.create_subkey(primary_bytes=primary_bytes,
+                                      subkey=signing_key,
+                                      signer_func=c.sign)
+        result = encode.create_subkey(primary_bytes=result,
+                                      subkey=encryption_key,
+                                      signer_func=c.sign)
+    else:  # add as primary
+        log.info('creating new %s GPG primary key for "%s"',
+                 args.ecdsa_curve, args.user_id)
+        # primary key for signing
+        primary = protocol.PublicKey(
+            curve_name=args.ecdsa_curve, created=args.time,
+            verifying_key=verifying_key, ecdh=False)
+        # subkey for encryption
+        subkey = protocol.PublicKey(
+            curve_name=formats.get_ecdh_curve_name(args.ecdsa_curve),
+            created=args.time, verifying_key=decryption_key, ecdh=True)
+
+        result = encode.create_primary(user_id=args.user_id,
+                                       pubkey=primary,
+                                       signer_func=c.sign)
+        result = encode.create_subkey(primary_bytes=result,
+                                      subkey=subkey,
+                                      signer_func=c.sign)
+
+    sys.stdout.write(protocol.armor(result, 'PUBLIC KEY BLOCK'))
+
+
+def run_create(device_type, args):
+    """Export public GPG key."""
+    util.setup_logging(verbosity=args.verbose)
+    log.warning('This GPG tool is still in EXPERIMENTAL mode, '
+                'so please note that the API and features may '
+                'change without backwards compatibility!')
+
+    existing_gpg = keyring.gpg_version().decode('ascii')
+    required_gpg = '>=2.1.11'
+    if semver.match(existing_gpg, required_gpg):
+        export_public_key(device_type, args)
+    else:
+        log.error('Existing gpg2 has version "%s" (%s required)',
+                  existing_gpg, required_gpg)
+
+
+def run_unlock(device_type, args):
+    """Unlock hardware device (for future interaction)."""
+    util.setup_logging(verbosity=args.verbose)
+    with device_type() as d:
+        log.info('unlocked %s device', d)
+
+
+def run_agent(device_type):
+    """Run a simple GPG-agent server."""
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--homedir', default=os.environ.get('GNUPGHOME'))
+    args, _ = parser.parse_known_args()
+
+    assert args.homedir
+    config_file = os.path.join(args.homedir, 'gpg-agent.conf')
+
+    lines = (line.strip() for line in open(config_file))
+    lines = (line for line in lines if line and not line.startswith('#'))
+    config = dict(line.split(' ', 1) for line in lines)
+
+    util.setup_logging(verbosity=int(config['verbosity']),
+                       filename=config['log-file'])
+    sock_path = keyring.get_agent_sock_path()
+    with server.unix_domain_socket_server(sock_path) as sock:
+        for conn in agent.yield_connections(sock):
+            with contextlib.closing(conn):
+                try:
+                    agent.handle_connection(conn=conn, device_type=device_type)
+                except StopIteration:
+                    log.info('stopping gpg-agent')
+                    return
+                except Exception as e:  # pylint: disable=broad-except
+                    log.exception('gpg-agent failed: %s', e)
+
+
+def main(device_type):
+    """Parse command-line arguments."""
+    parser = argparse.ArgumentParser()
+    subparsers = parser.add_subparsers()
+
+    p = subparsers.add_parser('create', help='Export public GPG key')
+    p.add_argument('user_id')
+    p.add_argument('-e', '--ecdsa-curve', default='nist256p1')
+    p.add_argument('-t', '--time', type=int, default=int(time.time()))
+    p.add_argument('-v', '--verbose', default=0, action='count')
+    p.add_argument('-s', '--subkey', default=False, action='store_true')
+    p.set_defaults(func=run_create)
+
+    p = subparsers.add_parser('unlock', help='Unlock the hardware device')
+    p.add_argument('-v', '--verbose', default=0, action='count')
+    p.set_defaults(func=run_unlock)
+
+    args = parser.parse_args()
+    return args.func(device_type=device_type, args=args)

libagent/gpg/agent.py

@@ -0,0 +1,171 @@
+"""GPG-agent utilities."""
+import binascii
+import logging
+
+from . import client, decode, keyring, protocol
+from .. import util
+
+log = logging.getLogger(__name__)
+
+
+def yield_connections(sock):
+    """Run a server on the specified socket."""
+    while True:
+        log.debug('waiting for connection on %s', sock.getsockname())
+        try:
+            conn, _ = sock.accept()
+        except KeyboardInterrupt:
+            return
+        conn.settimeout(None)
+        log.debug('accepted connection on %s', sock.getsockname())
+        yield conn
+
+
+def serialize(data):
+    """Serialize data according to ASSUAN protocol."""
+    for c in [b'%', b'\n', b'\r']:
+        escaped = '%{:02X}'.format(ord(c)).encode('ascii')
+        data = data.replace(c, escaped)
+    return data
+
+
+def sig_encode(r, s):
+    """Serialize ECDSA signature data into GPG S-expression."""
+    r = serialize(util.num2bytes(r, 32))
+    s = serialize(util.num2bytes(s, 32))
+    return b'(7:sig-val(5:ecdsa(1:r32:' + r + b')(1:s32:' + s + b')))'
+
+
+def open_connection(keygrip_bytes, device_type):
+    """
+    Connect to the device for the specified keygrip.
+
+    Parse GPG public key to find the first user ID, which is used to
+    specify the correct signature/decryption key on the device.
+    """
+    pubkey_dict, user_ids = decode.load_by_keygrip(
+        pubkey_bytes=keyring.export_public_keys(),
+        keygrip=keygrip_bytes)
+    # We assume the first user ID is used to generate TREZOR-based GPG keys.
+    user_id = user_ids[0]['value'].decode('ascii')
+    curve_name = protocol.get_curve_name_by_oid(pubkey_dict['curve_oid'])
+    ecdh = (pubkey_dict['algo'] == protocol.ECDH_ALGO_ID)
+
+    conn = client.Client(user_id, curve_name=curve_name, device_type=device_type)
+    pubkey = protocol.PublicKey(
+        curve_name=curve_name, created=pubkey_dict['created'],
+        verifying_key=conn.pubkey(ecdh=ecdh), ecdh=ecdh)
+    assert pubkey.key_id() == pubkey_dict['key_id']
+    assert pubkey.keygrip() == keygrip_bytes
+    return conn
+
+
+def pksign(keygrip, digest, algo, device_type):
+    """Sign a message digest using a private EC key."""
+    log.debug('signing %r digest (algo #%s)', digest, algo)
+    keygrip_bytes = binascii.unhexlify(keygrip)
+    conn = open_connection(keygrip_bytes, device_type=device_type)
+    r, s = conn.sign(binascii.unhexlify(digest))
+    result = sig_encode(r, s)
+    log.debug('result: %r', result)
+    return result
+
+
+def _serialize_point(data):
+    prefix = '{}:'.format(len(data)).encode('ascii')
+    # https://www.gnupg.org/documentation/manuals/assuan/Server-responses.html
+    return b'(5:value' + serialize(prefix + data) + b')'
+
+
+def parse_ecdh(line):
+    """Parse ECDH request and return remote public key."""
+    prefix, line = line.split(b' ', 1)
+    assert prefix == b'D'
+    exp, leftover = keyring.parse(keyring.unescape(line))
+    log.debug('ECDH s-exp: %r', exp)
+    assert not leftover
+    label, exp = exp
+    assert label == b'enc-val'
+    assert exp[0] == b'ecdh'
+    items = exp[1:]
+    log.debug('ECDH parameters: %r', items)
+    return dict(items)[b'e']
+
+
+def pkdecrypt(keygrip, conn, device_type):
+    """Handle decryption using ECDH."""
+    for msg in [b'S INQUIRE_MAXLEN 4096', b'INQUIRE CIPHERTEXT']:
+        keyring.sendline(conn, msg)
+
+    line = keyring.recvline(conn)
+    assert keyring.recvline(conn) == b'END'
+    remote_pubkey = parse_ecdh(line)
+
+    keygrip_bytes = binascii.unhexlify(keygrip)
+    conn = open_connection(keygrip_bytes, device_type=device_type)
+    return _serialize_point(conn.ecdh(remote_pubkey))
+
+
+@util.memoize
+def have_key(keygrip, device_type):
+    """Check if current keygrip correspond to a TREZOR-based key."""
+    try:
+        open_connection(keygrip_bytes=binascii.unhexlify(keygrip),
+                        device_type=device_type)
+        return True
+    except KeyError as e:
+        log.warning('HAVEKEY(%s) failed: %s', keygrip, e)
+        return False
+
+
+# pylint: disable=too-many-branches
+def handle_connection(conn, device_type):
+    """Handle connection from GPG binary using the ASSUAN protocol."""
+    keygrip = None
+    digest = None
+    algo = None
+    version = keyring.gpg_version()  # "Clone" existing GPG version
+
+    keyring.sendline(conn, b'OK')
+    for line in keyring.iterlines(conn):
+        parts = line.split(b' ')
+        command = parts[0]
+        args = parts[1:]
+        if command in {b'RESET', b'OPTION', b'SETKEYDESC'}:
+            pass  # reply with OK
+        elif command == b'GETINFO':
+            keyring.sendline(conn, b'D ' + version)
+        elif command == b'AGENT_ID':
+            keyring.sendline(conn, b'D TREZOR')  # "Fake" agent ID
+        elif command in {b'SIGKEY', b'SETKEY'}:
+            keygrip, = args
+        elif command == b'SETHASH':
+            algo, digest = args
+        elif command == b'PKSIGN':
+            sig = pksign(keygrip, digest, algo, device_type=device_type)
+            keyring.sendline(conn, b'D ' + sig)
+        elif command == b'PKDECRYPT':
+            sec = pkdecrypt(keygrip, conn, device_type=device_type)
+            keyring.sendline(conn, b'D ' + sec)
+        elif command == b'HAVEKEY':
+            if not have_key(keygrip=args[0], device_type=device_type):
+                keyring.sendline(conn,
+                                 b'ERR 67108881 No secret key <GPG Agent>')
+                return
+        elif command == b'KEYINFO':
+            keygrip, = args
+            # Dummy reply (mainly for 'gpg --edit' to succeed).
+            # For details, see GnuPG agent KEYINFO command help.
+            # https://git.gnupg.org/cgi-bin/gitweb.cgi?p=gnupg.git;a=blob;f=agent/command.c;h=c8b34e9882076b1b724346787781f657cac75499;hb=refs/heads/master#l1082
+            fmt = 'S KEYINFO {0} X - - - - - - -'
+            keyring.sendline(conn, fmt.format(keygrip).encode('ascii'))
+        elif command == b'BYE':
+            return
+        elif command == b'KILLAGENT':
+            keyring.sendline(conn, b'OK')
+            raise StopIteration
+        else:
+            log.error('unknown request: %r', line)
+            return
+
+        keyring.sendline(conn, b'OK')

libagent/gpg/client.py

@@ -0,0 +1,44 @@
+"""Device abstraction layer for GPG operations."""
+
+import logging
+
+from .. import device, formats, util
+
+log = logging.getLogger(__name__)
+
+
+class Client(object):
+    """Sign messages and get public keys from a hardware device."""
+
+    def __init__(self, user_id, curve_name, device_type):
+        """Connect to the device and retrieve required public key."""
+        self.device = device_type()
+        self.user_id = user_id
+        self.identity = device.interface.Identity(
+            identity_str='gpg://', curve_name=curve_name)
+        self.identity.identity_dict['host'] = user_id
+
+    def pubkey(self, ecdh=False):
+        """Return public key as VerifyingKey object."""
+        with self.device:
+            pubkey = self.device.pubkey(ecdh=ecdh, identity=self.identity)
+        return formats.decompress_pubkey(
+            pubkey=pubkey, curve_name=self.identity.curve_name)
+
+    def sign(self, digest):
+        """Sign the digest and return a serialized signature."""
+        log.info('please confirm GPG signature on %s for "%s"...',
+                 self.device, self.user_id)
+        if self.identity.curve_name == formats.CURVE_NIST256:
+            digest = digest[:32]  # sign the first 256 bits
+        log.debug('signing digest: %s', util.hexlify(digest))
+        with self.device:
+            sig = self.device.sign(blob=digest, identity=self.identity)
+        return (util.bytes2num(sig[:32]), util.bytes2num(sig[32:]))
+
+    def ecdh(self, pubkey):
+        """Derive shared secret using ECDH from remote public key."""
+        log.info('please confirm GPG decryption on %s for "%s"...',
+                 self.device, self.user_id)
+        with self.device:
+            return self.device.ecdh(pubkey=pubkey, identity=self.identity)

libagent/gpg/decode.py

@@ -0,0 +1,318 @@
+"""Decoders for GPG v2 data structures."""
+import base64
+import functools
+import hashlib
+import io
+import logging
+import struct
+
+import ecdsa
+import ed25519
+
+from . import protocol
+from .. import util
+
+log = logging.getLogger(__name__)
+
+
+def parse_subpackets(s):
+    """See https://tools.ietf.org/html/rfc4880#section-5.2.3.1 for details."""
+    subpackets = []
+    total_size = s.readfmt('>H')
+    data = s.read(total_size)
+    s = util.Reader(io.BytesIO(data))
+
+    while True:
+        try:
+            first = s.readfmt('B')
+        except EOFError:
+            break
+
+        if first < 192:
+            subpacket_len = first
+        elif first < 255:
+            subpacket_len = ((first - 192) << 8) + s.readfmt('B') + 192
+        else:  # first == 255
+            subpacket_len = s.readfmt('>L')
+
+        subpackets.append(s.read(subpacket_len))
+
+    return subpackets
+
+
+def parse_mpi(s):
+    """See https://tools.ietf.org/html/rfc4880#section-3.2 for details."""
+    bits = s.readfmt('>H')
+    blob = bytearray(s.read(int((bits + 7) // 8)))
+    return sum(v << (8 * i) for i, v in enumerate(reversed(blob)))
+
+
+def parse_mpis(s, n):
+    """Parse multiple MPIs from stream."""
+    return [parse_mpi(s) for _ in range(n)]
+
+
+def _parse_nist256p1_pubkey(mpi):
+    prefix, x, y = util.split_bits(mpi, 4, 256, 256)
+    if prefix != 4:
+        raise ValueError('Invalid MPI prefix: {}'.format(prefix))
+    point = ecdsa.ellipticcurve.Point(curve=ecdsa.NIST256p.curve,
+                                      x=x, y=y)
+    return ecdsa.VerifyingKey.from_public_point(
+        point=point, curve=ecdsa.curves.NIST256p,
+        hashfunc=hashlib.sha256)
+
+
+def _parse_ed25519_pubkey(mpi):
+    prefix, value = util.split_bits(mpi, 8, 256)
+    if prefix != 0x40:
+        raise ValueError('Invalid MPI prefix: {}'.format(prefix))
+    return ed25519.VerifyingKey(util.num2bytes(value, size=32))
+
+
+SUPPORTED_CURVES = {
+    b'\x2A\x86\x48\xCE\x3D\x03\x01\x07':
+        (_parse_nist256p1_pubkey, protocol.keygrip_nist256),
+    b'\x2B\x06\x01\x04\x01\xDA\x47\x0F\x01':
+        (_parse_ed25519_pubkey, protocol.keygrip_ed25519),
+    b'\x2B\x06\x01\x04\x01\x97\x55\x01\x05\x01':
+        (_parse_ed25519_pubkey, protocol.keygrip_curve25519),
+}
+
+RSA_ALGO_IDS = {1, 2, 3}
+ELGAMAL_ALGO_ID = 16
+DSA_ALGO_ID = 17
+ECDSA_ALGO_IDS = {18, 19, 22}  # {ecdsa, nist256, ed25519}
+
+
+def _parse_embedded_signatures(subpackets):
+    for packet in subpackets:
+        data = bytearray(packet)
+        if data[0] == 32:
+            # https://tools.ietf.org/html/rfc4880#section-5.2.3.26
+            stream = io.BytesIO(data[1:])
+            yield _parse_signature(util.Reader(stream))
+
+
+def has_custom_subpacket(signature_packet):
+    """Detect our custom public keys by matching subpacket data."""
+    return any(protocol.CUSTOM_KEY_LABEL == subpacket[1:]
+               for subpacket in signature_packet['unhashed_subpackets'])
+
+
+def _parse_signature(stream):
+    """See https://tools.ietf.org/html/rfc4880#section-5.2 for details."""
+    p = {'type': 'signature'}
+
+    to_hash = io.BytesIO()
+    with stream.capture(to_hash):
+        p['version'] = stream.readfmt('B')
+        p['sig_type'] = stream.readfmt('B')
+        p['pubkey_alg'] = stream.readfmt('B')
+        p['hash_alg'] = stream.readfmt('B')
+        p['hashed_subpackets'] = parse_subpackets(stream)
+
+    # https://tools.ietf.org/html/rfc4880#section-5.2.4
+    tail_to_hash = b'\x04\xff' + struct.pack('>L', to_hash.tell())
+
+    p['_to_hash'] = to_hash.getvalue() + tail_to_hash
+
+    p['unhashed_subpackets'] = parse_subpackets(stream)
+    embedded = list(_parse_embedded_signatures(p['unhashed_subpackets']))
+    if embedded:
+        log.debug('embedded sigs: %s', embedded)
+        p['embedded'] = embedded
+
+    p['hash_prefix'] = stream.readfmt('2s')
+    if p['pubkey_alg'] in ECDSA_ALGO_IDS:
+        p['sig'] = (parse_mpi(stream), parse_mpi(stream))
+    elif p['pubkey_alg'] in RSA_ALGO_IDS:  # RSA
+        p['sig'] = (parse_mpi(stream),)
+    elif p['pubkey_alg'] == DSA_ALGO_ID:
+        p['sig'] = (parse_mpi(stream), parse_mpi(stream))
+    else:
+        log.error('unsupported public key algo: %d', p['pubkey_alg'])
+
+    assert not stream.read()
+    return p
+
+
+def _parse_pubkey(stream, packet_type='pubkey'):
+    """See https://tools.ietf.org/html/rfc4880#section-5.5 for details."""
+    p = {'type': packet_type}
+    packet = io.BytesIO()
+    with stream.capture(packet):
+        p['version'] = stream.readfmt('B')
+        p['created'] = stream.readfmt('>L')
+        p['algo'] = stream.readfmt('B')
+        if p['algo'] in ECDSA_ALGO_IDS:
+            log.debug('parsing elliptic curve key')
+            # https://tools.ietf.org/html/rfc6637#section-11
+            oid_size = stream.readfmt('B')
+            oid = stream.read(oid_size)
+            assert oid in SUPPORTED_CURVES, util.hexlify(oid)
+            p['curve_oid'] = oid
+
+            mpi = parse_mpi(stream)
+            log.debug('mpi: %x (%d bits)', mpi, mpi.bit_length())
+            leftover = stream.read()
+            if leftover:
+                leftover = io.BytesIO(leftover)
+                # https://tools.ietf.org/html/rfc6637#section-8
+                # should be b'\x03\x01\x08\x07': SHA256 + AES128
+                size, = util.readfmt(leftover, 'B')
+                p['kdf'] = leftover.read(size)
+                p['secret'] = leftover.read()
+
+            parse_func, keygrip_func = SUPPORTED_CURVES[oid]
+            keygrip = keygrip_func(parse_func(mpi))
+            log.debug('keygrip: %s', util.hexlify(keygrip))
+            p['keygrip'] = keygrip
+
+        elif p['algo'] == DSA_ALGO_ID:
+            parse_mpis(stream, n=4)  # DSA keys are not supported
+        elif p['algo'] == ELGAMAL_ALGO_ID:
+            parse_mpis(stream, n=3)  # ElGamal keys are not supported
+        else:  # assume RSA
+            parse_mpis(stream, n=2)  # RSA keys are not supported
+        assert not stream.read()
+
+    # https://tools.ietf.org/html/rfc4880#section-12.2
+    packet_data = packet.getvalue()
+    data_to_hash = (b'\x99' + struct.pack('>H', len(packet_data)) +
+                    packet_data)
+    p['key_id'] = hashlib.sha1(data_to_hash).digest()[-8:]
+    p['_to_hash'] = data_to_hash
+    log.debug('key ID: %s', util.hexlify(p['key_id']))
+    return p
+
+_parse_subkey = functools.partial(_parse_pubkey, packet_type='subkey')
+
+
+def _parse_user_id(stream, packet_type='user_id'):
+    """See https://tools.ietf.org/html/rfc4880#section-5.11 for details."""
+    value = stream.read()
+    to_hash = b'\xb4' + util.prefix_len('>L', value)
+    return {'type': packet_type, 'value': value, '_to_hash': to_hash}
+
+# User attribute is handled as an opaque user ID
+_parse_attribute = functools.partial(_parse_user_id,
+                                     packet_type='user_attribute')
+
+PACKET_TYPES = {
+    2: _parse_signature,
+    5: _parse_pubkey,
+    6: _parse_pubkey,
+    7: _parse_subkey,
+    13: _parse_user_id,
+    14: _parse_subkey,
+    17: _parse_attribute,
+}
+
+
+def parse_packets(stream):
+    """
+    Support iterative parsing of available GPG packets.
+
+    See https://tools.ietf.org/html/rfc4880#section-4.2 for details.
+    """
+    reader = util.Reader(stream)
+    while True:
+        try:
+            value = reader.readfmt('B')
+        except EOFError:
+            return
+
+        log.debug('prefix byte: %s', bin(value))
+        assert util.bit(value, 7) == 1
+
+        tag = util.low_bits(value, 6)
+        if util.bit(value, 6) == 0:
+            length_type = util.low_bits(tag, 2)
+            tag = tag >> 2
+            fmt = {0: '>B', 1: '>H', 2: '>L'}[length_type]
+            packet_size = reader.readfmt(fmt)
+        else:
+            first = reader.readfmt('B')
+            if first < 192:
+                packet_size = first
+            elif first < 224:
+                packet_size = ((first - 192) << 8) + reader.readfmt('B') + 192
+            elif first == 255:
+                packet_size = reader.readfmt('>L')
+            else:
+                log.error('Partial Body Lengths unsupported')
+
+        log.debug('packet length: %d', packet_size)
+        packet_data = reader.read(packet_size)
+        packet_type = PACKET_TYPES.get(tag)
+
+        p = {'type': 'unknown', 'tag': tag, 'raw': packet_data}
+        if packet_type is not None:
+            try:
+                p = packet_type(util.Reader(io.BytesIO(packet_data)))
+                p['tag'] = tag
+            except ValueError:
+                log.exception('Skipping packet: %s', util.hexlify(packet_data))
+
+        log.debug('packet "%s": %s', p['type'], p)
+        yield p
+
+
+def digest_packets(packets, hasher):
+    """Compute digest on specified packets, according to '_to_hash' field."""
+    data_to_hash = io.BytesIO()
+    for p in packets:
+        data_to_hash.write(p['_to_hash'])
+    hasher.update(data_to_hash.getvalue())
+    return hasher.digest()
+
+
+HASH_ALGORITHMS = {
+    1: 'md5',
+    2: 'sha1',
+    3: 'ripemd160',
+    8: 'sha256',
+    9: 'sha384',
+    10: 'sha512',
+    11: 'sha224',
+}
+
+
+def load_by_keygrip(pubkey_bytes, keygrip):
+    """Return public key and first user ID for specified keygrip."""
+    stream = io.BytesIO(pubkey_bytes)
+    packets = list(parse_packets(stream))
+    packets_per_pubkey = []
+    for p in packets:
+        if p['type'] == 'pubkey':
+            # Add a new packet list for each pubkey.
+            packets_per_pubkey.append([])
+        packets_per_pubkey[-1].append(p)
+
+    for packets in packets_per_pubkey:
+        user_ids = [p for p in packets if p['type'] == 'user_id']
+        for p in packets:
+            if p.get('keygrip') == keygrip:
+                return p, user_ids
+    raise KeyError('{} keygrip not found'.format(util.hexlify(keygrip)))
+
+
+def load_signature(stream, original_data):
+    """Load signature from stream, and compute GPG digest for verification."""
+    signature, = list(parse_packets((stream)))
+    hash_alg = HASH_ALGORITHMS[signature['hash_alg']]
+    digest = digest_packets([{'_to_hash': original_data}, signature],
+                            hasher=hashlib.new(hash_alg))
+    assert signature['hash_prefix'] == digest[:2]
+    return signature, digest
+
+
+def remove_armor(armored_data):
+    """Decode armored data into its binary form."""
+    stream = io.BytesIO(armored_data)
+    lines = stream.readlines()[3:-1]
+    data = base64.b64decode(b''.join(lines))
+    payload, checksum = data[:-3], data[-3:]
+    assert util.crc24(payload) == checksum
+    return payload

libagent/gpg/encode.py

@@ -0,0 +1,103 @@
+"""Create GPG ECDSA signatures and public keys using TREZOR device."""
+import io
+import logging
+
+from . import decode, keyring, protocol
+from .. import util
+
+log = logging.getLogger(__name__)
+
+
+def create_primary(user_id, pubkey, signer_func, secret_bytes=b''):
+    """Export new primary GPG public key, ready for "gpg2 --import"."""
+    pubkey_packet = protocol.packet(tag=(5 if secret_bytes else 6),
+                                    blob=(pubkey.data() + secret_bytes))
+    user_id_packet = protocol.packet(tag=13,
+                                     blob=user_id.encode('ascii'))
+
+    data_to_sign = (pubkey.data_to_hash() +
+                    user_id_packet[:1] +
+                    util.prefix_len('>L', user_id.encode('ascii')))
+    hashed_subpackets = [
+        protocol.subpacket_time(pubkey.created),  # signature time
+        # https://tools.ietf.org/html/rfc4880#section-5.2.3.7
+        protocol.subpacket_byte(0x0B, 9),  # preferred symmetric algo (AES-256)
+        # https://tools.ietf.org/html/rfc4880#section-5.2.3.4
+        protocol.subpacket_byte(0x1B, 1 | 2),  # key flags (certify & sign)
+        # https://tools.ietf.org/html/rfc4880#section-5.2.3.21
+        protocol.subpacket_byte(0x15, 8),  # preferred hash (SHA256)
+        # https://tools.ietf.org/html/rfc4880#section-5.2.3.8
+        protocol.subpacket_byte(0x16, 0),  # preferred compression (none)
+        # https://tools.ietf.org/html/rfc4880#section-5.2.3.9
+        protocol.subpacket_byte(0x17, 0x80)  # key server prefs (no-modify)
+        # https://tools.ietf.org/html/rfc4880#section-5.2.3.17
+    ]
+    unhashed_subpackets = [
+        protocol.subpacket(16, pubkey.key_id()),  # issuer key id
+        protocol.CUSTOM_SUBPACKET]
+
+    signature = protocol.make_signature(
+        signer_func=signer_func,
+        public_algo=pubkey.algo_id,
+        data_to_sign=data_to_sign,
+        sig_type=0x13,  # user id & public key
+        hashed_subpackets=hashed_subpackets,
+        unhashed_subpackets=unhashed_subpackets)
+
+    sign_packet = protocol.packet(tag=2, blob=signature)
+    return pubkey_packet + user_id_packet + sign_packet
+
+
+def create_subkey(primary_bytes, subkey, signer_func, secret_bytes=b''):
+    """Export new subkey to GPG primary key."""
+    subkey_packet = protocol.packet(tag=(7 if secret_bytes else 14),
+                                    blob=(subkey.data() + secret_bytes))
+    packets = list(decode.parse_packets(io.BytesIO(primary_bytes)))
+    primary, user_id, signature = packets[:3]
+
+    data_to_sign = primary['_to_hash'] + subkey.data_to_hash()
+
+    if subkey.ecdh:
+        embedded_sig = None
+    else:
+        # Primary Key Binding Signature
+        hashed_subpackets = [
+            protocol.subpacket_time(subkey.created)]  # signature time
+        unhashed_subpackets = [
+            protocol.subpacket(16, subkey.key_id())]  # issuer key id
+        embedded_sig = protocol.make_signature(
+            signer_func=signer_func,
+            data_to_sign=data_to_sign,
+            public_algo=subkey.algo_id,
+            sig_type=0x19,
+            hashed_subpackets=hashed_subpackets,
+            unhashed_subpackets=unhashed_subpackets)
+
+    # Subkey Binding Signature
+
+    # Key flags: https://tools.ietf.org/html/rfc4880#section-5.2.3.21
+    # (certify & sign)                   (encrypt)
+    flags = (2) if (not subkey.ecdh) else (4 | 8)
+
+    hashed_subpackets = [
+        protocol.subpacket_time(subkey.created),  # signature time
+        protocol.subpacket_byte(0x1B, flags)]
+
+    unhashed_subpackets = []
+    unhashed_subpackets.append(protocol.subpacket(16, primary['key_id']))
+    if embedded_sig is not None:
+        unhashed_subpackets.append(protocol.subpacket(32, embedded_sig))
+    unhashed_subpackets.append(protocol.CUSTOM_SUBPACKET)
+
+    if not decode.has_custom_subpacket(signature):
+        signer_func = keyring.create_agent_signer(user_id['value'])
+
+    signature = protocol.make_signature(
+        signer_func=signer_func,
+        data_to_sign=data_to_sign,
+        public_algo=primary['algo'],
+        sig_type=0x18,
+        hashed_subpackets=hashed_subpackets,
+        unhashed_subpackets=unhashed_subpackets)
+    sign_packet = protocol.packet(tag=2, blob=signature)
+    return primary_bytes + subkey_packet + sign_packet

libagent/gpg/keyring.py

@@ -0,0 +1,229 @@
+"""Tools for doing signature using gpg-agent."""
+from __future__ import absolute_import, print_function, unicode_literals
+
+import binascii
+import io
+import logging
+import os
+import re
+import socket
+import subprocess
+
+from .. import util
+
+log = logging.getLogger(__name__)
+
+
+def get_agent_sock_path(sp=subprocess):
+    """Parse gpgconf output to find out GPG agent UNIX socket path."""
+    lines = sp.check_output(['gpgconf', '--list-dirs']).strip().split(b'\n')
+    dirs = dict(line.split(b':', 1) for line in lines)
+    return dirs[b'agent-socket']
+
+
+def connect_to_agent(sp=subprocess):
+    """Connect to GPG agent's UNIX socket."""
+    sock_path = get_agent_sock_path(sp=sp)
+    sp.check_call(['gpg-connect-agent', '/bye'])  # Make sure it's running
+    sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+    sock.connect(sock_path)
+    return sock
+
+
+def communicate(sock, msg):
+    """Send a message and receive a single line."""
+    sendline(sock, msg.encode('ascii'))
+    return recvline(sock)
+
+
+def sendline(sock, msg):
+    """Send a binary message, followed by EOL."""
+    log.debug('<- %r', msg)
+    sock.sendall(msg + b'\n')
+
+
+def recvline(sock):
+    """Receive a single line from the socket."""
+    reply = io.BytesIO()
+
+    while True:
+        c = sock.recv(1)
+        if not c:
+            return None  # socket is closed
+
+        if c == b'\n':
+            break
+        reply.write(c)
+
+    result = reply.getvalue()
+    log.debug('-> %r', result)
+    return result
+
+
+def iterlines(conn):
+    """Iterate over input, split by lines."""
+    while True:
+        line = recvline(conn)
+        if line is None:
+            break
+        yield line
+
+
+def unescape(s):
+    """Unescape ASSUAN message (0xAB <-> '%AB')."""
+    s = bytearray(s)
+    i = 0
+    while i < len(s):
+        if s[i] == ord('%'):
+            hex_bytes = bytes(s[i+1:i+3])
+            value = int(hex_bytes.decode('ascii'), 16)
+            s[i:i+3] = [value]
+        i += 1
+    return bytes(s)
+
+
+def parse_term(s):
+    """Parse single s-expr term from bytes."""
+    size, s = s.split(b':', 1)
+    size = int(size)
+    return s[:size], s[size:]
+
+
+def parse(s):
+    """Parse full s-expr from bytes."""
+    if s.startswith(b'('):
+        s = s[1:]
+        name, s = parse_term(s)
+        values = [name]
+        while not s.startswith(b')'):
+            value, s = parse(s)
+            values.append(value)
+        return values, s[1:]
+    else:
+        return parse_term(s)
+
+
+def _parse_ecdsa_sig(args):
+    (r, sig_r), (s, sig_s) = args
+    assert r == b'r'
+    assert s == b's'
+    return (util.bytes2num(sig_r),
+            util.bytes2num(sig_s))
+
+# DSA and EDDSA happen to have the same structure as ECDSA signatures
+_parse_dsa_sig = _parse_ecdsa_sig
+_parse_eddsa_sig = _parse_ecdsa_sig
+
+
+def _parse_rsa_sig(args):
+    (s, sig_s), = args
+    assert s == b's'
+    return (util.bytes2num(sig_s),)
+
+
+def parse_sig(sig):
+    """Parse signature integer values from s-expr."""
+    label, sig = sig
+    assert label == b'sig-val'
+    algo_name = sig[0]
+    parser = {b'rsa': _parse_rsa_sig,
+              b'ecdsa': _parse_ecdsa_sig,
+              b'eddsa': _parse_eddsa_sig,
+              b'dsa': _parse_dsa_sig}[algo_name]
+    return parser(args=sig[1:])
+
+
+def sign_digest(sock, keygrip, digest, sp=subprocess, environ=None):
+    """Sign a digest using specified key using GPG agent."""
+    hash_algo = 8  # SHA256
+    assert len(digest) == 32
+
+    assert communicate(sock, 'RESET').startswith(b'OK')
+
+    ttyname = sp.check_output(['tty']).strip()
+    options = ['ttyname={}'.format(ttyname)]  # set TTY for passphrase entry
+
+    display = (environ or os.environ).get('DISPLAY')
+    if display is not None:
+        options.append('display={}'.format(display))
+
+    for opt in options:
+        assert communicate(sock, 'OPTION {}'.format(opt)) == b'OK'
+
+    assert communicate(sock, 'SIGKEY {}'.format(keygrip)) == b'OK'
+    hex_digest = binascii.hexlify(digest).upper().decode('ascii')
+    assert communicate(sock, 'SETHASH {} {}'.format(hash_algo,
+                                                    hex_digest)) == b'OK'
+
+    assert communicate(sock, 'SETKEYDESC '
+                       'Sign+a+new+TREZOR-based+subkey') == b'OK'
+    assert communicate(sock, 'PKSIGN') == b'OK'
+    while True:
+        line = recvline(sock).strip()
+        if line.startswith(b'S PROGRESS'):
+            continue
+        else:
+            break
+    line = unescape(line)
+    log.debug('unescaped: %r', line)
+    prefix, sig = line.split(b' ', 1)
+    if prefix != b'D':
+        raise ValueError(prefix)
+
+    sig, leftover = parse(sig)
+    assert not leftover, leftover
+    return parse_sig(sig)
+
+
+def gpg_command(args, env=None):
+    """Prepare common GPG command line arguments."""
+    if env is None:
+        env = os.environ
+    cmd = ['gpg2']
+    homedir = env.get('GNUPGHOME')
+    if homedir:
+        cmd.extend(['--homedir', homedir])
+    return cmd + args
+
+
+def get_keygrip(user_id, sp=subprocess):
+    """Get a keygrip of the primary GPG key of the specified user."""
+    args = gpg_command(['--list-keys', '--with-keygrip', user_id])
+    output = sp.check_output(args).decode('ascii')
+    return re.findall(r'Keygrip = (\w+)', output)[0]
+
+
+def gpg_version(sp=subprocess):
+    """Get a keygrip of the primary GPG key of the specified user."""
+    args = gpg_command(['--version'])
+    output = sp.check_output(args)
+    line = output.split(b'\n')[0]  # b'gpg (GnuPG) 2.1.11'
+    return line.split(b' ')[-1]  # b'2.1.11'
+
+
+def export_public_key(user_id, sp=subprocess):
+    """Export GPG public key for specified `user_id`."""
+    args = gpg_command(['--export', user_id])
+    result = sp.check_output(args=args)
+    if not result:
+        log.error('could not find public key %r in local GPG keyring', user_id)
+        raise KeyError(user_id)
+    return result
+
+
+def export_public_keys(sp=subprocess):
+    """Export all GPG public keys."""
+    args = gpg_command(['--export'])
+    return sp.check_output(args=args)
+
+
+def create_agent_signer(user_id):
+    """Sign digest with existing GPG keys using gpg-agent tool."""
+    sock = connect_to_agent()
+    keygrip = get_keygrip(user_id)
+
+    def sign(digest):
+        """Sign the digest and return an ECDSA/RSA/DSA signature."""
+        return sign_digest(sock=sock, keygrip=keygrip, digest=digest)
+
+    return sign

libagent/gpg/protocol.py

@@ -0,0 +1,271 @@
+"""GPG protocol utilities."""
+
+import base64
+import hashlib
+import logging
+import struct
+
+from .. import formats, util
+
+log = logging.getLogger(__name__)
+
+
+def packet(tag, blob):
+    """Create small GPG packet."""
+    assert len(blob) < 2**32
+
+    if len(blob) < 2**8:
+        length_type = 0
+    elif len(blob) < 2**16:
+        length_type = 1
+    else:
+        length_type = 2
+
+    fmt = ['>B', '>H', '>L'][length_type]
+    leading_byte = 0x80 | (tag << 2) | (length_type)
+    return struct.pack('>B', leading_byte) + util.prefix_len(fmt, 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 subpacket_prefix_len(item):
+    """Prefix subpacket length according to RFC 4880 section-5.2.3.1."""
+    n = len(item)
+    if n >= 8384:
+        prefix = b'\xFF' + struct.pack('>L', n)
+    elif n >= 192:
+        n = n - 192
+        prefix = struct.pack('BB', (n // 256) + 192, n % 256)
+    else:
+        prefix = struct.pack('B', n)
+    return prefix + item
+
+
+def subpackets(*items):
+    """Serialize several GPG subpackets."""
+    prefixed = [subpacket_prefix_len(item) for item in items]
+    return util.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 = bytearray(data_size)
+    for i in range(data_size):
+        data_bytes[i] = value & 0xFF
+        value = value >> 8
+
+    data_bytes.reverse()
+    return struct.pack('>H', bits) + bytes(data_bytes)
+
+
+def _serialize_nist256(vk):
+    return mpi((4 << 512) |
+               (vk.pubkey.point.x() << 256) |
+               (vk.pubkey.point.y()))
+
+
+def _serialize_ed25519(vk):
+    return mpi((0x40 << 256) |
+               util.bytes2num(vk.to_bytes()))
+
+
+def _compute_keygrip(params):
+    parts = []
+    for name, value in params:
+        exp = '{}:{}{}:'.format(len(name), name, len(value))
+        parts.append(b'(' + exp.encode('ascii') + value + b')')
+
+    return hashlib.sha1(b''.join(parts)).digest()
+
+
+def keygrip_nist256(vk):
+    """Compute keygrip for NIST256 curve public keys."""
+    curve = vk.curve.curve
+    gen = vk.curve.generator
+    g = (4 << 512) | (gen.x() << 256) | gen.y()
+    point = vk.pubkey.point
+    q = (4 << 512) | (point.x() << 256) | point.y()
+
+    return _compute_keygrip([
+        ['p', util.num2bytes(curve.p(), size=32)],
+        ['a', util.num2bytes(curve.a() % curve.p(), size=32)],
+        ['b', util.num2bytes(curve.b() % curve.p(), size=32)],
+        ['g', util.num2bytes(g, size=65)],
+        ['n', util.num2bytes(vk.curve.order, size=32)],
+        ['q', util.num2bytes(q, size=65)],
+    ])
+
+
+def keygrip_ed25519(vk):
+    """Compute keygrip for Ed25519 public keys."""
+    # pylint: disable=line-too-long
+    return _compute_keygrip([
+        ['p', util.num2bytes(0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFED, size=32)],  # nopep8
+        ['a', b'\x01'],
+        ['b', util.num2bytes(0x2DFC9311D490018C7338BF8688861767FF8FF5B2BEBE27548A14B235ECA6874A, size=32)],  # nopep8
+        ['g', util.num2bytes(0x04216936D3CD6E53FEC0A4E231FDD6DC5C692CC7609525A7B2C9562D608F25D51A6666666666666666666666666666666666666666666666666666666666666658, size=65)],  # nopep8
+        ['n', util.num2bytes(0x1000000000000000000000000000000014DEF9DEA2F79CD65812631A5CF5D3ED, size=32)],  # nopep8
+        ['q', vk.to_bytes()],
+    ])
+
+
+def keygrip_curve25519(vk):
+    """Compute keygrip for Curve25519 public keys."""
+    # pylint: disable=line-too-long
+    return _compute_keygrip([
+        ['p', util.num2bytes(0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFED, size=32)],  # nopep8
+        ['a', b'\x01\xDB\x41'],
+        ['b', b'\x01'],
+        ['g', util.num2bytes(0x04000000000000000000000000000000000000000000000000000000000000000920ae19a1b8a086b4e01edd2c7748d14c923d4d7e6d7c61b229e9c5a27eced3d9, size=65)],  # nopep8
+        ['n', util.num2bytes(0x1000000000000000000000000000000014DEF9DEA2F79CD65812631A5CF5D3ED, size=32)],  # nopep8
+        ['q', 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,
+        'serialize': _serialize_nist256,
+        'keygrip': keygrip_nist256,
+    },
+    formats.CURVE_ED25519: {
+        'oid': b'\x2B\x06\x01\x04\x01\xDA\x47\x0F\x01',
+        'algo_id': 22,
+        'serialize': _serialize_ed25519,
+        'keygrip': keygrip_ed25519,
+    },
+    formats.ECDH_CURVE25519: {
+        'oid': b'\x2B\x06\x01\x04\x01\x97\x55\x01\x05\x01',
+        'algo_id': 18,
+        'serialize': _serialize_ed25519,
+        'keygrip': keygrip_curve25519,
+    },
+}
+
+ECDH_ALGO_ID = 18
+
+CUSTOM_KEY_LABEL = b'TREZOR-GPG'  # marks "our" pubkey
+CUSTOM_SUBPACKET_ID = 26  # use "policy URL" subpacket
+CUSTOM_SUBPACKET = subpacket(CUSTOM_SUBPACKET_ID, CUSTOM_KEY_LABEL)
+
+
+def get_curve_name_by_oid(oid):
+    """Return curve name matching specified OID, or raise KeyError."""
+    for curve_name, info in SUPPORTED_CURVES.items():
+        if info['oid'] == oid:
+            return curve_name
+    raise KeyError('Unknown OID: {!r}'.format(oid))
+
+
+class PublicKey(object):
+    """GPG representation for public key packets."""
+
+    def __init__(self, curve_name, created, verifying_key, ecdh=False):
+        """Contruct using a ECDSA VerifyingKey object."""
+        self.curve_name = curve_name
+        self.curve_info = SUPPORTED_CURVES[curve_name]
+        self.created = int(created)  # time since Epoch
+        self.verifying_key = verifying_key
+        self.ecdh = bool(ecdh)
+        if ecdh:
+            self.algo_id = ECDH_ALGO_ID
+            self.ecdh_packet = b'\x03\x01\x08\x07'
+        else:
+            self.algo_id = self.curve_info['algo_id']
+            self.ecdh_packet = b''
+
+    def keygrip(self):
+        """Compute GPG keygrip of the verifying key."""
+        return self.curve_info['keygrip'](self.verifying_key)
+
+    def data(self):
+        """Data for packet creation."""
+        header = struct.pack('>BLB',
+                             4,             # version
+                             self.created,  # creation
+                             self.algo_id)  # public key algorithm ID
+        oid = util.prefix_len('>B', self.curve_info['oid'])
+        blob = self.curve_info['serialize'](self.verifying_key)
+        return header + oid + blob + self.ecdh_packet
+
+    def data_to_hash(self):
+        """Data for digest computation."""
+        return b'\x99' + util.prefix_len('>H', self.data())
+
+    def _fingerprint(self):
+        return hashlib.sha1(self.data_to_hash()).digest()
+
+    def key_id(self):
+        """Short (8 byte) GPG key ID."""
+        return self._fingerprint()[-8:]
+
+    def __repr__(self):
+        """Short (8 hexadecimal digits) GPG key ID."""
+        hex_key_id = util.hexlify(self.key_id())[-8:]
+        return 'GPG public key {}/{}'.format(self.curve_name, hex_key_id)
+
+    __str__ = __repr__
+
+
+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).decode('ascii')
+    checksum = base64.b64encode(util.crc24(blob)).decode('ascii')
+    tail = '-----END PGP {}-----\n'.format(type_str)
+    return head + _split_lines(body, 64) + '=' + checksum + '\n' + tail
+
+
+def make_signature(signer_func, data_to_sign, public_algo,
+                   hashed_subpackets, unhashed_subpackets, sig_type=0):
+    """Create new GPG signature."""
+    # pylint: disable=too-many-arguments
+    header = struct.pack('>BBBB',
+                         4,         # version
+                         sig_type,  # rfc4880 (section-5.2.1)
+                         public_algo,
+                         8)         # hash_alg (SHA256)
+    hashed = subpackets(*hashed_subpackets)
+    unhashed = subpackets(*unhashed_subpackets)
+    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()
+    log.debug('signing digest: %s', util.hexlify(digest))
+    params = signer_func(digest=digest)
+    sig = b''.join(mpi(p) for p in params)
+
+    return bytes(header + hashed + unhashed +
+                 digest[:2] +  # used for decoder's sanity check
+                 sig)  # actual ECDSA signature

libagent/gpg/tests/__init__.py

@@ -0,0 +1 @@
+"""Tests for GPG module."""

libagent/gpg/tests/test_decode.py

@@ -0,0 +1,62 @@
+import glob
+import io
+import os
+
+import pytest
+
+from .. import decode, protocol
+from ... import util
+
+
+def test_subpackets():
+    s = io.BytesIO(b'\x00\x05\x02\xAB\xCD\x01\xEF')
+    assert decode.parse_subpackets(util.Reader(s)) == [b'\xAB\xCD', b'\xEF']
+
+
+def test_subpackets_prefix():
+    for n in [0, 1, 2, 4, 5, 10, 191, 192, 193,
+              255, 256, 257, 8383, 8384, 65530]:
+        item = b'?' * n  # create dummy subpacket
+        prefixed = protocol.subpackets(item)
+        result = decode.parse_subpackets(util.Reader(io.BytesIO(prefixed)))
+        assert [item] == result
+
+
+def test_mpi():
+    s = io.BytesIO(b'\x00\x09\x01\x23')
+    assert decode.parse_mpi(util.Reader(s)) == 0x123
+
+    s = io.BytesIO(b'\x00\x09\x01\x23\x00\x03\x05')
+    assert decode.parse_mpis(util.Reader(s), n=2) == [0x123, 5]
+
+
+cwd = os.path.join(os.path.dirname(__file__))
+input_files = glob.glob(os.path.join(cwd, '*.gpg'))
+
+
+@pytest.fixture(params=input_files)
+def public_key_path(request):
+    return request.param
+
+
+def test_gpg_files(public_key_path):  # pylint: disable=redefined-outer-name
+    with open(public_key_path, 'rb') as f:
+        assert list(decode.parse_packets(f))
+
+
+def test_has_custom_subpacket():
+    sig = {'unhashed_subpackets': []}
+    assert not decode.has_custom_subpacket(sig)
+
+    custom_markers = [
+        protocol.CUSTOM_SUBPACKET,
+        protocol.subpacket(10, protocol.CUSTOM_KEY_LABEL),
+    ]
+    for marker in custom_markers:
+        sig = {'unhashed_subpackets': [marker]}
+        assert decode.has_custom_subpacket(sig)
+
+
+def test_load_by_keygrip_missing():
+    with pytest.raises(KeyError):
+        decode.load_by_keygrip(pubkey_bytes=b'', keygrip=b'')

libagent/gpg/tests/test_keyring.py

@@ -0,0 +1,101 @@
+import io
+
+import mock
+
+from .. import keyring
+
+
+def test_unescape_short():
+    assert keyring.unescape(b'abc%0AX%0D %25;.-+()') == b'abc\nX\r %;.-+()'
+
+
+def test_unescape_long():
+    escaped = (b'D (7:sig-val(3:dsa(1:r32:\x1d\x15.\x12\xe8h\x19\xd9O\xeb\x06'
+               b'yD?a:/\xae\xdb\xac\x93\xa6\x86\xcbs\xb8\x03\xf1\xcb\x89\xc7'
+               b'\x1f)(1:s32:%25\xb5\x04\x94\xc7\xc4X\xc7\xe0%0D\x08\xbb%0DuN'
+               b'\x9c6}[\xc2=t\x8c\xfdD\x81\xe8\xdd\x86=\xe2\xa9)))')
+    unescaped = (b'D (7:sig-val(3:dsa(1:r32:\x1d\x15.\x12\xe8h\x19\xd9O\xeb'
+                 b'\x06yD?a:/\xae\xdb\xac\x93\xa6\x86\xcbs\xb8\x03\xf1\xcb\x89'
+                 b'\xc7\x1f)(1:s32:%\xb5\x04\x94\xc7\xc4X\xc7\xe0\r\x08\xbb\ru'
+                 b'N\x9c6}[\xc2=t\x8c\xfdD\x81\xe8\xdd\x86=\xe2\xa9)))')
+    assert keyring.unescape(escaped) == unescaped
+
+
+def test_parse_term():
+    assert keyring.parse(b'4:abcdXXX') == (b'abcd', b'XXX')
+
+
+def test_parse_ecdsa():
+    sig, rest = keyring.parse(b'(7:sig-val(5:ecdsa'
+                              b'(1:r2:\x01\x02)(1:s2:\x03\x04)))')
+    values = [[b'r', b'\x01\x02'], [b's', b'\x03\x04']]
+    assert sig == [b'sig-val', [b'ecdsa'] + values]
+    assert rest == b''
+    assert keyring.parse_sig(sig) == (0x102, 0x304)
+
+
+def test_parse_rsa():
+    sig, rest = keyring.parse(b'(7:sig-val(3:rsa(1:s4:\x01\x02\x03\x04)))')
+    assert sig == [b'sig-val', [b'rsa', [b's', b'\x01\x02\x03\x04']]]
+    assert rest == b''
+    assert keyring.parse_sig(sig) == (0x1020304,)
+
+
+class FakeSocket(object):
+    def __init__(self):
+        self.rx = io.BytesIO()
+        self.tx = io.BytesIO()
+
+    def recv(self, n):
+        return self.rx.read(n)
+
+    def sendall(self, data):
+        self.tx.write(data)
+
+
+def test_sign_digest():
+    sock = FakeSocket()
+    sock.rx.write(b'OK Pleased to meet you, process XYZ\n')
+    sock.rx.write(b'OK\n' * 6)
+    sock.rx.write(b'D (7:sig-val(3:rsa(1:s16:0123456789ABCDEF)))\n')
+    sock.rx.seek(0)
+    keygrip = '1234'
+    digest = b'A' * 32
+    sp = mock.Mock(spec=['check_output'])
+    sp.check_output.return_value = '/dev/pts/0'
+    sig = keyring.sign_digest(sock=sock, keygrip=keygrip,
+                              digest=digest, sp=sp,
+                              environ={'DISPLAY': ':0'})
+    assert sig == (0x30313233343536373839414243444546,)
+    assert sock.tx.getvalue() == b'''RESET
+OPTION ttyname=/dev/pts/0
+OPTION display=:0
+SIGKEY 1234
+SETHASH 8 4141414141414141414141414141414141414141414141414141414141414141
+SETKEYDESC Sign+a+new+TREZOR-based+subkey
+PKSIGN
+'''
+
+
+def test_iterlines():
+    sock = FakeSocket()
+    sock.rx.write(b'foo\nbar\nxyz')
+    sock.rx.seek(0)
+    assert list(keyring.iterlines(sock)) == [b'foo', b'bar']
+
+
+def test_get_agent_sock_path():
+    sp = mock.Mock(spec=['check_output'])
+    sp.check_output.return_value = b'''sysconfdir:/usr/local/etc/gnupg
+bindir:/usr/local/bin
+libexecdir:/usr/local/libexec
+libdir:/usr/local/lib/gnupg
+datadir:/usr/local/share/gnupg
+localedir:/usr/local/share/locale
+dirmngr-socket:/run/user/1000/gnupg/S.dirmngr
+agent-ssh-socket:/run/user/1000/gnupg/S.gpg-agent.ssh
+agent-socket:/run/user/1000/gnupg/S.gpg-agent
+homedir:/home/roman/.gnupg
+'''
+    expected = b'/run/user/1000/gnupg/S.gpg-agent'
+    assert keyring.get_agent_sock_path(sp=sp) == expected

libagent/gpg/tests/test_protocol.py

@@ -0,0 +1,107 @@
+import ecdsa
+import ed25519
+import pytest
+
+from .. import protocol
+from ... import formats
+
+
+def test_packet():
+    assert protocol.packet(1, b'') == b'\x84\x00'
+    assert protocol.packet(2, b'A') == b'\x88\x01A'
+    blob = b'B' * 0xAB
+    assert protocol.packet(3, blob) == b'\x8c\xAB' + blob
+    blob = b'C' * 0x1234
+    assert protocol.packet(3, blob) == b'\x8d\x12\x34' + blob
+    blob = b'D' * 0x12345678
+    assert protocol.packet(4, blob) == b'\x92\x12\x34\x56\x78' + blob
+
+
+def test_subpackets():
+    assert protocol.subpacket(1, b'') == b'\x01'
+    assert protocol.subpacket(2, '>H', 0x0304) == b'\x02\x03\x04'
+    assert protocol.subpacket_long(9, 0x12345678) == b'\x09\x12\x34\x56\x78'
+    assert protocol.subpacket_time(0x12345678) == b'\x02\x12\x34\x56\x78'
+    assert protocol.subpacket_byte(0xAB, 0xCD) == b'\xAB\xCD'
+    assert protocol.subpackets() == b'\x00\x00'
+    assert protocol.subpackets(b'ABC', b'12345') == b'\x00\x0A\x03ABC\x0512345'
+
+
+def test_mpi():
+    assert protocol.mpi(0x123) == b'\x00\x09\x01\x23'
+
+
+def test_armor():
+    data = bytearray(range(256))
+    assert protocol.armor(data, 'TEST') == '''-----BEGIN PGP TEST-----
+Version: GnuPG v2
+
+AAECAwQFBgcICQoLDA0ODxAREhMUFRYXGBkaGxwdHh8gISIjJCUmJygpKissLS4v
+MDEyMzQ1Njc4OTo7PD0+P0BBQkNERUZHSElKS0xNTk9QUVJTVFVWV1hZWltcXV5f
+YGFiY2RlZmdoaWprbG1ub3BxcnN0dXZ3eHl6e3x9fn+AgYKDhIWGh4iJiouMjY6P
+kJGSk5SVlpeYmZqbnJ2en6ChoqOkpaanqKmqq6ytrq+wsbKztLW2t7i5uru8vb6/
+wMHCw8TFxsfIycrLzM3Oz9DR0tPU1dbX2Nna29zd3t/g4eLj5OXm5+jp6uvs7e7v
+8PHy8/T19vf4+fr7/P3+/w==
+=W700
+-----END PGP TEST-----
+'''
+
+
+def test_make_signature():
+    def signer_func(digest):
+        assert digest == (b'\xd0\xe5]|\x8bP\xe6\x91\xb3\xe8+\xf4A\xf0`(\xb1'
+                          b'\xc7\xf4;\x86\x97s\xdb\x9a\xda\xee< \xcb\x9e\x00')
+        return (7, 8)
+
+    sig = protocol.make_signature(
+        signer_func=signer_func,
+        data_to_sign=b'Hello World!',
+        public_algo=22,
+        hashed_subpackets=[protocol.subpacket_time(1)],
+        unhashed_subpackets=[],
+        sig_type=25)
+    assert sig == (b'\x04\x19\x16\x08\x00\x06\x05\x02'
+                   b'\x00\x00\x00\x01\x00\x00\xd0\xe5\x00\x03\x07\x00\x04\x08')
+
+
+def test_nist256p1():
+    sk = ecdsa.SigningKey.from_secret_exponent(secexp=1, curve=ecdsa.NIST256p)
+    vk = sk.get_verifying_key()
+    pk = protocol.PublicKey(curve_name=formats.CURVE_NIST256,
+                            created=42, verifying_key=vk)
+    assert repr(pk) == 'GPG public key nist256p1/F82361D9'
+    assert pk.keygrip() == b'\x95\x85.\x91\x7f\xe2\xc3\x91R\xba\x99\x81\x92\xb5y\x1d\xb1\\\xdc\xf0'
+
+
+def test_nist256p1_ecdh():
+    sk = ecdsa.SigningKey.from_secret_exponent(secexp=1, curve=ecdsa.NIST256p)
+    vk = sk.get_verifying_key()
+    pk = protocol.PublicKey(curve_name=formats.CURVE_NIST256,
+                            created=42, verifying_key=vk, ecdh=True)
+    assert repr(pk) == 'GPG public key nist256p1/5811DF46'
+    assert pk.keygrip() == b'\x95\x85.\x91\x7f\xe2\xc3\x91R\xba\x99\x81\x92\xb5y\x1d\xb1\\\xdc\xf0'
+
+
+def test_ed25519():
+    sk = ed25519.SigningKey(b'\x00' * 32)
+    vk = sk.get_verifying_key()
+    pk = protocol.PublicKey(curve_name=formats.CURVE_ED25519,
+                            created=42, verifying_key=vk)
+    assert repr(pk) == 'GPG public key ed25519/36B40FE6'
+    assert pk.keygrip() == b'\xbf\x01\x90l\x17\xb64\xa3-\xf4\xc0gr\x99\x18<\xddBQ?'
+
+
+def test_curve25519():
+    sk = ed25519.SigningKey(b'\x00' * 32)
+    vk = sk.get_verifying_key()
+    pk = protocol.PublicKey(curve_name=formats.ECDH_CURVE25519,
+                            created=42, verifying_key=vk)
+    assert repr(pk) == 'GPG public key curve25519/69460384'
+    assert pk.keygrip() == b'x\xd6\x86\xe4\xa6\xfc;\x0fY\xe1}Lw\xc4\x9ed\xf1Q\x8a\x00'
+
+
+def test_get_curve_name_by_oid():
+    for name, info in protocol.SUPPORTED_CURVES.items():
+        assert protocol.get_curve_name_by_oid(info['oid']) == name
+    with pytest.raises(KeyError):
+        protocol.get_curve_name_by_oid('BAD_OID')