pgp_mime/crypt.py

   1 # Copyright (C) 2012 W. Trevor King <wking@tremily.us>
   2 #
   3 # This file is part of pgp-mime.
   4 #
   5 # pgp-mime is free software: you can redistribute it and/or modify it under the
   6 # terms of the GNU General Public License as published by the Free Software
   7 # Foundation, either version 3 of the License, or (at your option) any later
   8 # version.
   9 #
  10 # pgp-mime is distributed in the hope that it will be useful, but WITHOUT ANY
  11 # WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  12 # A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
  13 #
  14 # You should have received a copy of the GNU General Public License along with
  15 # pgp-mime.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 import codecs as _codecs
  18 import logging as _logging
  19 import os as _os
  20 import os.path as _os_path
  21 from _socket import socket as _Socket
  22 import socket as _socket
  23 import subprocess as _subprocess
  24
  25 from pyassuan import client as _client
  26 from pyassuan import common as _common
  27
  28 from . import LOG as _LOG
  29
  30
  31 def connect(client, filename, **kwargs):
  32     filename = _os_path.expanduser(filename)
  33     if False:
  34         socket = _socket.socket(_socket.AF_UNIX, _socket.SOCK_STREAM)
  35         socket.connect(filename)
  36         client.input = socket.makefile('rb')
  37         client.output = socket.makefile('wb')
  38     else:
  39         p = _subprocess.Popen(
  40             filename, stdin=_subprocess.PIPE, stdout=_subprocess.PIPE,
  41             close_fds=True, **kwargs)
  42         client.input = p.stdout
  43         client.output = p.stdin
  44         socket = p
  45     client.connect()
  46     return socket
  47
  48 def get_client(**kwargs):
  49     client = _client.AssuanClient(name='pgp-mime', close_on_disconnect=True)
  50     client.logger.setLevel(_LOG.level)
  51     socket = connect(client, '~/src/gpgme/build/src/gpgme-tool', **kwargs)
  52     #socket = connect(client, '~/.assuan/S.gpgme-tool', **kwargs)
  53     return (client, socket)
  54
  55 def disconnect(client, socket):
  56     client.make_request(_common.Request('BYE'))
  57     client.disconnect()
  58     if isinstance(socket, _Socket):
  59         socket.shutdown(_socket.SHUT_RDWR)
  60         socket.close()
  61     else:
  62         status = socket.wait()
  63         assert status == 0, status
  64
  65 def hello(client):
  66     responses,data = client.get_responses()  # get initial 'OK' from server
  67     client.make_request(_common.Request('ARMOR', 'true'))
  68
  69 def _read(fd, buffersize=512):
  70     d = []
  71     while True:
  72         try:
  73             new = _os.read(fd, buffersize)
  74         except Exception as e:
  75             _LOG.warn('error while reading: {}'.format(e))
  76             break
  77         if not new:
  78             break
  79         d.append(new)
  80     return b''.join(d)
  81
  82 def _write(fd, data):
  83     i = 0
  84     while i < len(data):
  85         i += _os.write(fd, data[i:])
  86
  87
  88 def sign_and_encrypt_bytes(data, signers=None, recipients=None,
  89                            always_trust=False, mode='detach',
  90                            allow_default_signer=False):
  91     r"""Sign ``data`` with ``signers`` and encrypt to ``recipients``.
  92
  93     Just sign:
  94
  95     >>> print(sign_and_encrypt_bytes(
  96     ...     bytes(b'Hello'), signers=['pgp-mime@invalid.com']))
  97     ... # doctest: +ELLIPSIS
  98     b'-----BEGIN PGP SIGNATURE-----\n...-----END PGP SIGNATURE-----\n'
  99
 100     Just encrypt:
 101
 102     >>> sign_and_encrypt_bytes(
 103     ...     bytes(b'Hello'), recipients=['pgp-mime@invalid.com'],
 104     ...     always_trust=True)
 105     ... # doctest: +ELLIPSIS
 106     b'-----BEGIN PGP MESSAGE-----\n...-----END PGP MESSAGE-----\n'
 107
 108     Sign and encrypt:
 109
 110     >>> sign_and_encrypt_bytes(
 111     ...     bytes(b'Hello'), signers=['pgp-mime@invalid.com'],
 112     ...     recipients=['pgp-mime@invalid.com'], always_trust=True)
 113     ... # doctest: +ELLIPSIS
 114     b'-----BEGIN PGP MESSAGE-----\n...-----END PGP MESSAGE-----\n'
 115     """
 116     input_read,input_write = _os.pipe()
 117     output_read,output_write = _os.pipe()
 118     client,socket = get_client(pass_fds=(input_read, output_write))
 119     _os.close(input_read)
 120     _os.close(output_write)
 121     try:
 122         hello(client)
 123         if signers:
 124             for signer in signers:
 125                 client.make_request(_common.Request('SIGNER', signer))
 126         if recipients:
 127             for recipient in recipients:
 128                 client.make_request(_common.Request('RECIPIENT', recipient))
 129         client.make_request(
 130             _common.Request('INPUT', 'FD={}'.format(input_read)))
 131         client.make_request(
 132             _common.Request('OUTPUT', 'FD={}'.format(output_write)))
 133         parameters = []
 134         if signers or allow_default_signer:
 135             if recipients:
 136                 command = 'SIGN_ENCRYPT'
 137             else:
 138                 command = 'SIGN'
 139                 parameters.append('--{}'.format(mode))
 140         elif recipients:
 141             command = 'ENCRYPT'
 142         else:
 143             raise ValueError('must specify at least one signer or recipient')
 144         if always_trust:
 145             parameters.append('--always-trust')
 146         _write(input_write, data)
 147         _os.close(input_write)
 148         input_write = -1
 149         client.make_request(
 150             _common.Request(command, ' '.join(parameters)))
 151         d = _read(output_read)
 152     finally:
 153         disconnect(client, socket)
 154         for fd in [input_write, output_read]:
 155             if fd >= 0:
 156                 _os.close(fd)
 157     return d
 158
 159 def decrypt_bytes(data):
 160     r"""Decrypt ``data``.
 161
 162     >>> b = '\n'.join([
 163     ...     '-----BEGIN PGP MESSAGE-----',
 164     ...     'Version: GnuPG v2.0.17 (GNU/Linux)',
 165     ...     '',
 166     ...     'hQEMA1Ea7aZDMrbjAQf/TAqLjksZSJxSqkBxYT5gtLQoXY6isvRZg2apjs7CW0y2',
 167     ...     'tFK/ptnVYAq2OtWQFhbiJXj8hmwJyyFfb3lghpeu4ihO52JgkkwOpmJb6dxjOi83',
 168     ...     'qDwaGOogEPH38BNLuwdrMCW0jmNROwvS796PtqSGUaJTuIiKUB8lETwPwIHrDc11',
 169     ...     'N3RWStE5uShNkXXQXplUoeCKf3N4XguXym+GQCqJQzlEMrkkDdr4l7mzvt3Nf8EA',
 170     ...     'SgSak086tUoo9x8IN5PJCuOJkcXcjQzFcpqOsA7dyZKO8NeQUZv2JvlZuorckNvN',
 171     ...     'xx3PwW0a8VeJgTQrh64ZK/d3F3gNHUTzXkq/UIn25tJFAcmSUwxtsBal7p8zAeCV',
 172     ...     '8zefsHRQ5Y03IBeYBcVJBhDS9XfvwLQTJiGGstPCxzKTwSUT1MzV5t5twG/STDCc',
 173     ...     'uxW3wSdo',
 174     ...     '=bZI+',
 175     ...     '-----END PGP MESSAGE-----',
 176     ...     ''
 177     ...     ]).encode('us-ascii')
 178     >>> decrypt_bytes(b)
 179     b'Success!\n'
 180     """
 181     input_read,input_write = _os.pipe()
 182     output_read,output_write = _os.pipe()
 183     client,socket = get_client(pass_fds=(input_read, output_write))
 184     _os.close(input_read)
 185     _os.close(output_write)
 186     try:
 187         hello(client)
 188         client.make_request(
 189             _common.Request('INPUT', 'FD={}'.format(input_read)))
 190         client.make_request(
 191             _common.Request('OUTPUT', 'FD={}'.format(output_write)))
 192         _write(input_write, data)
 193         _os.close(input_write)
 194         input_write = -1
 195         client.make_request(_common.Request('DECRYPT'))
 196         d = _read(output_read)
 197     finally:
 198         disconnect(client, socket)
 199         for fd in [input_write, output_read]:
 200             if fd >= 0:
 201                 _os.close(fd)
 202     return d
 203
 204 def verify_bytes(data, signature=None, always_trust=False):
 205     r"""Verify a signature on ``data``, possibly decrypting first.
 206
 207     These tests assume you didn't trust the distributed test key.
 208
 209     >>> b = '\n'.join([
 210     ...     '-----BEGIN PGP MESSAGE-----',
 211     ...     'Version: GnuPG v2.0.17 (GNU/Linux)',
 212     ...     '',
 213     ...     'hQEMA1Ea7aZDMrbjAQf/YM1SeFzNGz0DnUynaEyhfGCvcqmjtbN1PtZMpT7VaQLN',
 214     ...     'a+c0faskr79Atz0+2IBR7CDOlcETrRtH2EnrWukbRIDtmffNFGuhMRTNfnQ15OIN',
 215     ...     'qrmt2P5gXznsgnm2XjzTK7S/Cc3Aq+zjaDrDt7bIedEdz+EyNgaKuL/lB9cAB8xL',
 216     ...     'YYp/yn55Myjair2idgzsa7w/QXdE3RhpyRLqR2Jgz4P1I1xOgUYnylbpIZL9FOKN',
 217     ...     'NR3RQhkGdANBku8otfthb5ZUGsNMV45ct4V8PE+xChjFb9gcwpaf1hhoIF/sYHD5',
 218     ...     'Bkf+v/J8F40KGYY16b0DjQIUlnra9y7q9jj0h2bvc9LAtgHtVUso133LLcVYl7RP',
 219     ...     'Vjyz9Ps366BtIdPlAL4CoF5hEcMKS5J3h1vRlyAKN4uHENl5vKvoxn7ID3JhhWQc',
 220     ...     '6QrPGis64zi3OnYor34HPh/KNJvkgOQkekmtYuTxnkiONA4lhMDJgeaVZ9WZq+GV',
 221     ...     'MaCvCFGNYU2TV4V8wMlnUbF8d5bDQ83g8MxIVKdDcnBzzYLZha+qmz4Spry9iB53',
 222     ...     'Sg/sM5H8gWWSl7Oj1lxVg7o7IscpQfVt6zL6jD2VjL3L3Hu7WEXIrcGZtvrP4d+C',
 223     ...     'TGYWiGlh5B2UCFk2bVctfw8W/QfaVvJYD4Rfqta2V2p14KIJLFRSGa1g26W4ixrH',
 224     ...     'XKxgaA3AIfJ+6c5RoisRLuYCxvQi91wkE9hAXR+inXK4Hq4SmiHoeITZFhHP3hh3',
 225     ...     'rbpp8mopiMNxWqCbuqgILP6pShn4oPclu9aR8uJ1ziDxISTGYC71mvLUERUjFn2L',
 226     ...     'fu6C0+TCC9RmeyL+eNdM6cjs1G7YR6yX',
 227     ...     '=phHd',
 228     ...     '-----END PGP MESSAGE-----',
 229     ...     '',
 230     ...     ]).encode('us-ascii')
 231     >>> output,verified,result = verify_bytes(b)
 232     >>> output
 233     b'Success!\n'
 234     >>> verified
 235     False
 236     >>> print(str(result, 'utf-8').replace('\x00', ''))
 237     ... # doctest: +REPORT_UDIFF
 238     <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
 239     <gpgme>
 240       <verify-result>
 241         <signatures>
 242           <signature>
 243             <summary value="0x0" />
 244             <fpr>B2EDBE0E771A4B8708DD16A7511AEDA64332B6E3</fpr>
 245             <status value="0x0">Success &lt;Unspecified source&gt;</status>
 246             <timestamp unix="1332357237i" />
 247             <exp-timestamp unix="0i" />
 248             <wrong-key-usage value="0x0" />
 249             <pka-trust value="0x0" />
 250             <chain-model value="0x0" />
 251             <validity value="0x0" />
 252             <validity-reason value="0x0">Success &lt;Unspecified source&gt;</validity-reason>
 253             <pubkey-algo value="0x1">RSA</pubkey-algo>
 254             <hash-algo value="0x8">SHA256</hash-algo>
 255           </signature>
 256         </signatures>
 257       </verify-result>
 258     </gpgme>
 259     <BLANKLINE>
 260     >>> b = b'Success!\n'
 261     >>> signature = '\n'.join([
 262     ...     '-----BEGIN PGP SIGNATURE-----',
 263     ...     'Version: GnuPG v2.0.17 (GNU/Linux)',
 264     ...     '',
 265     ...     'iQEcBAEBAgAGBQJPaiw/AAoJEFEa7aZDMrbj93gH/1fQPXLjUTpONJUTmvGoMLNA',
 266     ...     'W9ZhjpUL5i6rRqYGUvQ4kTEDuPMxkMrCyFCDHEhSDHufMek6Nso5/HeJn3aqxlgs',
 267     ...     'hmNlvAq4FI6JQyFL7eCp/XG9cPx1p42dTI7JAih8FuK21sS4m/H5XP3R/6KXC99D',
 268     ...     '39rrXCvvR+yNgKe2dxuJwmKuLteVlcWxiIQwVrYK70GtJHC5BO79G8yGccWoEy9C',
 269     ...     '9JkJiyNptqZyFjGBNmMmrCSFZ7ZFA02RB+laRmwuIiozw4TJYEksxPrgZMbbcFzx',
 270     ...     'zs3JHyV23+Fz1ftalvwskHE7tJkX9Ub8iBMNZ/KxJXXdPdpuMdEYVjoUehkQBQE=',
 271     ...     '=rRBP',
 272     ...     '-----END PGP SIGNATURE-----',
 273     ...     '',
 274     ...     ]).encode('us-ascii')
 275     >>> output,verified,result = verify_bytes(b, signature=signature)
 276     >>> output
 277     b'Success!\n'
 278     >>> verified
 279     False
 280     >>> print(str(result, 'utf-8').replace('\x00', ''))
 281     ... # doctest: +REPORT_UDIFF
 282     <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
 283     <gpgme>
 284       <verify-result>
 285         <signatures>
 286           <signature>
 287             <summary value="0x0" />
 288             <fpr>B2EDBE0E771A4B8708DD16A7511AEDA64332B6E3</fpr>
 289             <status value="0x0">Success &lt;Unspecified source&gt;</status>
 290             <timestamp unix="1332358207i" />
 291             <exp-timestamp unix="0i" />
 292             <wrong-key-usage value="0x0" />
 293             <pka-trust value="0x0" />
 294             <chain-model value="0x0" />
 295             <validity value="0x0" />
 296             <validity-reason value="0x0">Success &lt;Unspecified source&gt;</validity-reason>
 297             <pubkey-algo value="0x1">RSA</pubkey-algo>
 298             <hash-algo value="0x2">SHA1</hash-algo>
 299           </signature>
 300         </signatures>
 301       </verify-result>
 302     </gpgme>
 303     <BLANKLINE>
 304     """
 305     input_read,input_write = _os.pipe()
 306     pass_fds = [input_read]
 307     if signature:
 308         message_read,message_write = _os.pipe()
 309         output_read = -1
 310         pass_fds.append(message_read)
 311     else:
 312         message_write = -1
 313         output_read,output_write = _os.pipe()
 314         pass_fds.append(output_write)
 315     client,socket = get_client(pass_fds=pass_fds)
 316     _os.close(input_read)
 317     if signature:
 318         _os.close(message_read)
 319     else:
 320         _os.close(output_write)
 321     verified = result = None
 322     try:
 323         hello(client)
 324         client.make_request(
 325             _common.Request('INPUT', 'FD={}'.format(input_read)))
 326         if signature:
 327             client.make_request(
 328                 _common.Request('MESSAGE', 'FD={}'.format(message_read)))
 329         else:
 330             client.make_request(
 331                 _common.Request('OUTPUT', 'FD={}'.format(output_write)))
 332         if signature:
 333             _write(input_write, signature)
 334             _os.close(input_write)
 335             input_write = -1
 336             _write(message_write, data)
 337             _os.close(message_write)
 338             message_write = -1
 339         else:
 340             _write(input_write, data)
 341             _os.close(input_write)
 342             input_write = -1
 343         client.make_request(_common.Request('VERIFY'))
 344         if signature:
 345             plain = data
 346         else:
 347             plain = _read(output_read)
 348         rs,result = client.make_request(_common.Request('RESULT'))
 349         verified = True
 350         for line in result.splitlines():
 351             if b'<status ' in line and b'Success' not in line:
 352                 verified = False
 353             elif b'<pka-trust' in line and b'0x2' not in line:
 354                 verified = False
 355     finally:
 356         disconnect(client, socket)
 357         for fd in [input_write, message_write, output_read]:
 358             if fd >= 0:
 359                 _os.close(fd)
 360     return (plain, verified, result)