Files
trezor-agent/libagent/gpg/__init__.py
Michael Parks 362ddcc707 Quote PATH when writing agent invocation script
If the PATH contains spaces, the agent invocation script will fail parsing. This quotes the variable so that spaces don't break the script.
2020-05-17 00:41:56 -06:00

321 lines
12 KiB
Python

"""
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 functools
import logging
import os
import re
import subprocess
import sys
import time
import pkg_resources
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(device=device_type())
identity = client.create_identity(user_id=args.user_id,
curve_name=args.ecdsa_curve)
verifying_key = c.pubkey(identity=identity, ecdh=False)
decryption_key = c.pubkey(identity=identity, ecdh=True)
signer_func = functools.partial(c.sign, identity=identity)
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=signer_func)
result = encode.create_subkey(primary_bytes=result,
subkey=encryption_key,
signer_func=signer_func)
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=signer_func)
result = encode.create_subkey(primary_bytes=result,
subkey=subkey,
signer_func=signer_func)
return protocol.armor(result, 'PUBLIC KEY BLOCK')
def verify_gpg_version():
"""Make sure that the installed GnuPG is not too old."""
existing_gpg = keyring.gpg_version().decode('ascii')
required_gpg = '>=2.1.11'
msg = 'Existing GnuPG has version "{}" ({} required)'.format(existing_gpg,
required_gpg)
if not semver.match(existing_gpg, required_gpg):
log.error(msg)
def check_output(args):
"""Runs command and returns the output as string."""
log.debug('run: %s', args)
out = subprocess.check_output(args=args).decode('utf-8')
log.debug('out: %r', out)
return out
def check_call(args, stdin=None, env=None):
"""Runs command and verifies its success."""
log.debug('run: %s%s', args, ' {}'.format(env) if env else '')
subprocess.check_call(args=args, stdin=stdin, env=env)
def write_file(path, data):
"""Writes data to specified path."""
with open(path, 'w') as f:
log.debug('setting %s contents:\n%s', path, data)
f.write(data)
return f
def run_init(device_type, args):
"""Initialize hardware-based GnuPG identity."""
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!')
verify_gpg_version()
# Prepare new GPG home directory for hardware-based identity
device_name = os.path.basename(sys.argv[0]).rsplit('-', 1)[0]
log.info('device name: %s', device_name)
homedir = args.homedir
if not homedir:
homedir = os.path.expanduser('~/.gnupg/{}'.format(device_name))
log.info('GPG home directory: %s', homedir)
if os.path.exists(homedir):
log.error('GPG home directory %s exists, '
'remove it manually if required', homedir)
sys.exit(1)
check_call(['mkdir', '-p', homedir])
check_call(['chmod', '700', homedir])
agent_path = util.which('{}-gpg-agent'.format(device_name))
# Prepare GPG agent invocation script (to pass the PATH from environment).
with open(os.path.join(homedir, 'run-agent.sh'), 'w') as f:
f.write(r"""#!/bin/sh
export PATH="{0}"
{1} \
-vv \
--pin-entry-binary={pin_entry_binary} \
--passphrase-entry-binary={passphrase_entry_binary} \
--cache-expiry-seconds={cache_expiry_seconds} \
$*
""".format(os.environ['PATH'], agent_path, **vars(args)))
check_call(['chmod', '700', f.name])
run_agent_script = f.name
# Prepare GPG configuration file
with open(os.path.join(homedir, 'gpg.conf'), 'w') as f:
f.write("""# Hardware-based GPG configuration
agent-program {0}
personal-digest-preferences SHA512
default-key \"{1}\"
""".format(run_agent_script, args.user_id))
# Prepare a helper script for setting up the new identity
with open(os.path.join(homedir, 'env'), 'w') as f:
f.write("""#!/bin/bash
set -eu
export GNUPGHOME={0}
COMMAND=$*
if [ -z "${{COMMAND}}" ]
then
${{SHELL}}
else
${{COMMAND}}
fi
""".format(homedir))
check_call(['chmod', '700', f.name])
# Generate new GPG identity and import into GPG keyring
pubkey = write_file(os.path.join(homedir, 'pubkey.asc'),
export_public_key(device_type, args))
verbosity = ('-' + ('v' * args.verbose)) if args.verbose else '--quiet'
check_call(keyring.gpg_command(['--homedir', homedir, verbosity,
'--import', pubkey.name]))
# Make new GPG identity with "ultimate" trust (via its fingerprint)
out = check_output(keyring.gpg_command(['--homedir', homedir,
'--list-public-keys',
'--with-fingerprint',
'--with-colons']))
fpr = re.findall('fpr:::::::::([0-9A-F]+):', out)[0]
f = write_file(os.path.join(homedir, 'ownertrust.txt'), fpr + ':6\n')
check_call(keyring.gpg_command(['--homedir', homedir,
'--import-ownertrust', f.name]))
# Load agent and make sure it responds with the new identity
check_call(keyring.gpg_command(['--homedir', homedir,
'--list-secret-keys', args.user_id]))
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 _server_from_assuan_fd(env):
fd = env.get('_assuan_connection_fd')
if fd is None:
return None
log.info('using fd=%r for UNIX socket server', fd)
return server.unix_domain_socket_server_from_fd(int(fd))
def _server_from_sock_path(env):
sock_path = keyring.get_agent_sock_path(env=env)
return server.unix_domain_socket_server(sock_path)
def run_agent(device_type):
"""Run a simple GPG-agent server."""
p = argparse.ArgumentParser()
p.add_argument('--homedir', default=os.environ.get('GNUPGHOME'))
p.add_argument('-v', '--verbose', default=0, action='count')
p.add_argument('--server', default=False, action='store_true',
help='Use stdin/stdout for communication with GPG.')
p.add_argument('--pin-entry-binary', type=str, default='pinentry',
help='Path to PIN entry UI helper.')
p.add_argument('--passphrase-entry-binary', type=str, default='pinentry',
help='Path to passphrase entry UI helper.')
p.add_argument('--cache-expiry-seconds', type=float, default=float('inf'),
help='Expire passphrase from cache after this duration.')
args, _ = p.parse_known_args()
assert args.homedir
log_file = os.path.join(args.homedir, 'gpg-agent.log')
util.setup_logging(verbosity=args.verbose, filename=log_file)
log.debug('sys.argv: %s', sys.argv)
log.debug('os.environ: %s', os.environ)
log.debug('pid: %d, parent pid: %d', os.getpid(), os.getppid())
try:
env = {'GNUPGHOME': args.homedir, 'PATH': os.environ['PATH']}
pubkey_bytes = keyring.export_public_keys(env=env)
device_type.ui = device.ui.UI(device_type=device_type,
config=vars(args))
handler = agent.Handler(device=device_type(),
pubkey_bytes=pubkey_bytes)
sock_server = _server_from_assuan_fd(os.environ)
if sock_server is None:
sock_server = _server_from_sock_path(env)
with sock_server as sock:
for conn in agent.yield_connections(sock):
with contextlib.closing(conn):
try:
handler.handle(conn)
except agent.AgentStop:
log.info('stopping gpg-agent')
return
except IOError as e:
log.info('connection closed: %s', e)
return
except Exception as e: # pylint: disable=broad-except
log.exception('handler failed: %s', e)
except Exception as e: # pylint: disable=broad-except
log.exception('gpg-agent failed: %s', e)
def main(device_type):
"""Parse command-line arguments."""
epilog = ('See https://github.com/romanz/trezor-agent/blob/master/'
'doc/README-GPG.md for usage examples.')
parser = argparse.ArgumentParser(epilog=epilog)
agent_package = device_type.package_name()
resources_map = {r.key: r for r in pkg_resources.require(agent_package)}
resources = [resources_map[agent_package], resources_map['libagent']]
versions = '\n'.join('{}={}'.format(r.key, r.version) for r in resources)
parser.add_argument('--version', help='print the version info',
action='version', version=versions)
subparsers = parser.add_subparsers(title='Action', dest='action')
subparsers.required = True
p = subparsers.add_parser('init',
help='initialize hardware-based GnuPG identity')
p.add_argument('user_id')
p.add_argument('-e', '--ecdsa-curve', default='nist256p1')
p.add_argument('-t', '--time', type=int, default=0)
p.add_argument('-v', '--verbose', default=0, action='count')
p.add_argument('-s', '--subkey', default=False, action='store_true')
p.add_argument('--homedir', type=str, default=os.environ.get('GNUPGHOME'),
help='Customize GnuPG home directory for the new identity.')
p.add_argument('--pin-entry-binary', type=str, default='pinentry',
help='Path to PIN entry UI helper.')
p.add_argument('--passphrase-entry-binary', type=str, default='pinentry',
help='Path to passphrase entry UI helper.')
p.add_argument('--cache-expiry-seconds', type=float, default=float('inf'),
help='Expire passphrase from cache after this duration.')
p.set_defaults(func=run_init)
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()
device_type.ui = device.ui.UI(device_type=device_type, config=vars(args))
return args.func(device_type=device_type, args=args)