| 1 | #! /usr/bin/env python3 |
| 2 | # -*- coding: utf-8 -*- |
| 3 | """********************************************************************* |
| 4 | * Edward is free software: you can redistribute it and/or modify * |
| 5 | * it under the terms of the GNU Affero Public License as published by * |
| 6 | * the Free Software Foundation, either version 3 of the License, or * |
| 7 | * (at your option) any later version. * |
| 8 | * * |
| 9 | * Edward is distributed in the hope that it will be useful, * |
| 10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of * |
| 11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * |
| 12 | * GNU Affero Public License for more details. * |
| 13 | * * |
| 14 | * You should have received a copy of the GNU Affero Public License * |
| 15 | * along with Edward. If not, see <http://www.gnu.org/licenses/>. * |
| 16 | * * |
| 17 | * Copyright (C) 2014-2015 Andrew Engelbrecht (AGPLv3+) * |
| 18 | * Copyright (C) 2014 Josh Drake (AGPLv3+) * |
| 19 | * Copyright (C) 2014 Lisa Marie Maginnis (AGPLv3+) * |
| 20 | * Copyright (C) 2009-2015 Tails developers <tails@boum.org> ( GPLv3+) * |
| 21 | * Copyright (C) 2009 W. Trevor King <wking@drexel.edu> ( GPLv2+) * |
| 22 | * * |
| 23 | * Special thanks to Josh Drake for writing the original edward bot! :) * |
| 24 | * * |
| 25 | ************************************************************************ |
| 26 | |
| 27 | Code sourced from these projects: |
| 28 | |
| 29 | * http://agpl.fsf.org/emailselfdefense.fsf.org/edward/CURRENT/edward.tar.gz |
| 30 | * https://git-tails.immerda.ch/whisperback/tree/whisperBack/encryption.py?h=feature/python3 |
| 31 | * http://www.physics.drexel.edu/~wking/code/python/send_pgp_mime |
| 32 | """ |
| 33 | |
| 34 | import sys |
| 35 | import gpgme |
| 36 | import re |
| 37 | import io |
| 38 | import os |
| 39 | import importlib |
| 40 | |
| 41 | import email.parser |
| 42 | import email.message |
| 43 | import email.encoders |
| 44 | |
| 45 | from email.mime.multipart import MIMEMultipart |
| 46 | from email.mime.application import MIMEApplication |
| 47 | from email.mime.nonmultipart import MIMENonMultipart |
| 48 | |
| 49 | import edward_config |
| 50 | |
| 51 | langs = ["de", "el", "en", "fr", "ja", "pt-br", "ro", "ru", "tr"] |
| 52 | |
| 53 | """This list contains the abbreviated names of reply languages available to |
| 54 | edward.""" |
| 55 | |
| 56 | |
| 57 | match_types = [('clearsign', |
| 58 | '-----BEGIN PGP SIGNED MESSAGE-----.*?-----BEGIN PGP SIGNATURE-----.*?-----END PGP SIGNATURE-----'), |
| 59 | ('message', |
| 60 | '-----BEGIN PGP MESSAGE-----.*?-----END PGP MESSAGE-----'), |
| 61 | ('pubkey', |
| 62 | '-----BEGIN PGP PUBLIC KEY BLOCK-----.*?-----END PGP PUBLIC KEY BLOCK-----'), |
| 63 | ('detachedsig', |
| 64 | '-----BEGIN PGP SIGNATURE-----.*?-----END PGP SIGNATURE-----')] |
| 65 | |
| 66 | """This list of tuples matches query names with re.search() queries used |
| 67 | to find GPG data for edward to process.""" |
| 68 | |
| 69 | |
| 70 | class EddyMsg (object): |
| 71 | """ |
| 72 | The EddyMsg class represents relevant parts of a mime message. |
| 73 | |
| 74 | The represented message can be single-part or multi-part. |
| 75 | |
| 76 | 'multipart' is set to True if there are multiple mime parts. |
| 77 | |
| 78 | 'subparts' points to a list of mime sub-parts if it is a multi-part |
| 79 | message. Otherwise it points to an empty list. |
| 80 | |
| 81 | 'payload_bytes' contains the raw mime-decoded bytes that haven't been |
| 82 | encoded into a character set. |
| 83 | |
| 84 | 'payload_pieces' is a list of objects containing strings that when strung |
| 85 | together form the fully-decoded string representation of the mime part. |
| 86 | |
| 87 | The 'charset' describes the character set of payload_bytes. |
| 88 | |
| 89 | The 'filename', 'content_type' and 'description_list' come from the mime |
| 90 | part parameters. |
| 91 | """ |
| 92 | |
| 93 | multipart = False |
| 94 | subparts = [] |
| 95 | |
| 96 | payload_bytes = None |
| 97 | payload_pieces = [] |
| 98 | |
| 99 | charset = None |
| 100 | filename = None |
| 101 | content_type = None |
| 102 | description_list = None |
| 103 | |
| 104 | |
| 105 | class PayloadPiece (object): |
| 106 | """ |
| 107 | PayloadPiece represents a complte or sub-section of a mime part. |
| 108 | |
| 109 | Instances of this class are often strung together within one or more arrays |
| 110 | pointed to by each instance of the EddyMsg class. |
| 111 | |
| 112 | 'piece_type' refers to a string whose value describes the content of |
| 113 | 'string'. Examples include "pubkey", for public keys, and "message", for |
| 114 | encrypted data (or armored signatures until they are known to be such.) The |
| 115 | names derive from the header and footer of each of these ascii-encoded gpg |
| 116 | blocks. |
| 117 | |
| 118 | 'string' contains some string of text, such as non-GPG text, an encrypted |
| 119 | block of text, a signature, or a public key. |
| 120 | |
| 121 | 'gpg_data' points to any instances of GPGData that have been created based |
| 122 | on the contents of 'string'. |
| 123 | """ |
| 124 | |
| 125 | piece_type = None |
| 126 | string = None |
| 127 | gpg_data = None |
| 128 | |
| 129 | |
| 130 | class GPGData (object): |
| 131 | """ |
| 132 | GPGData holds info from decryption, sig. verification, and/or pub. keys. |
| 133 | |
| 134 | Instances of this class contain decrypted information, signature |
| 135 | fingerprints and/or fingerprints of processed and imported public keys. |
| 136 | |
| 137 | 'decrypted' is set to True if 'plainobj' was created from encrypted data. |
| 138 | |
| 139 | 'plainobj' points to any decrypted, or signed part of, a GPG signature. It |
| 140 | is intended to be an instance of the EddyMsg class. |
| 141 | |
| 142 | 'sigs' is a list of fingerprints of keys used to sign the data in plainobj. |
| 143 | |
| 144 | 'keys' is a list of fingerprints of keys obtained in public key blocks. |
| 145 | """ |
| 146 | |
| 147 | decrypted = False |
| 148 | |
| 149 | plainobj = None |
| 150 | sigs = [] |
| 151 | keys = [] |
| 152 | |
| 153 | |
| 154 | class ReplyInfo (object): |
| 155 | """ |
| 156 | ReplyInfo contains details that edward uses in generating its reply. |
| 157 | |
| 158 | Instances of this class contain information about whether a message was |
| 159 | successfully encrypted or signed, and whether a public key was attached, or |
| 160 | retrievable, from the local GPG store. It stores the fingerprints of |
| 161 | potential encryption key candidates and the message (if any at all) to |
| 162 | quote in edward's reply. |
| 163 | |
| 164 | 'replies' points one of the dictionaries of translated replies. |
| 165 | |
| 166 | 'target_key' refers to the fingerprint of a key used to sign encrypted |
| 167 | data. This is the preferred key, if it is set, and if is available. |
| 168 | |
| 169 | 'fallback_target_key' referst to the fingerprint of a key used to sign |
| 170 | unencrypted data; alternatively it may be a public key attached to the |
| 171 | message. |
| 172 | |
| 173 | 'msg_to_quote' refers to the part of a message which edward should quote in |
| 174 | his reply. This should remain as None if there was no encrypted and singed |
| 175 | part. This is to avoid making edward a service for decrypting other |
| 176 | people's messages to edward. |
| 177 | |
| 178 | 'success_decrypt' is set to True if edward could decrypt part of the |
| 179 | message. |
| 180 | |
| 181 | 'failed_decrypt' is set to True if edward failed to decrypt part of the |
| 182 | message. |
| 183 | |
| 184 | 'publick_key_received' is set to True if edward successfully imported a |
| 185 | public key. |
| 186 | |
| 187 | 'no_public_key' is set to True if edward doesn't have a key to encrypt to |
| 188 | when replying to the user. |
| 189 | |
| 190 | 'sig_success' is set to True if edward could to some extent verify the |
| 191 | signature of a signed part of the message to edward. |
| 192 | |
| 193 | 'sig_failure' is set to True if edward failed to some extent verify the |
| 194 | signature of a signed part of the message to edward. |
| 195 | """ |
| 196 | |
| 197 | replies = None |
| 198 | |
| 199 | target_key = None |
| 200 | fallback_target_key = None |
| 201 | msg_to_quote = "" |
| 202 | |
| 203 | success_decrypt = False |
| 204 | failed_decrypt = False |
| 205 | public_key_received = False |
| 206 | no_public_key = False |
| 207 | sig_success = False |
| 208 | sig_failure = False |
| 209 | |
| 210 | |
| 211 | def main (): |
| 212 | |
| 213 | """ |
| 214 | This is the main function for edward, a GPG reply bot. |
| 215 | |
| 216 | Edward responds to GPG-encrypted and signed mail, encrypting and signing |
| 217 | the response if the user's public key is, or was, included in the message. |
| 218 | |
| 219 | Args: |
| 220 | None |
| 221 | |
| 222 | Returns: |
| 223 | Nothing |
| 224 | |
| 225 | Pre: |
| 226 | Mime or plaintext email passing in through standard input. Portions of |
| 227 | the email may be encrypted. If the To: address contains the text |
| 228 | "edward-ja", then the reply will contain a reply written in the |
| 229 | Japanese language. There are other languages as well. The default |
| 230 | language is English. |
| 231 | |
| 232 | Post: |
| 233 | A reply email will be printed to standard output. The contents of the |
| 234 | reply email depends on whether the original email was encrypted or not, |
| 235 | has or doesn't have a signature, whether a public key used in the |
| 236 | original message is provided or locally stored, and the language |
| 237 | implied by the To: address in the original email. |
| 238 | """ |
| 239 | |
| 240 | handle_args() |
| 241 | |
| 242 | gpgme_ctx = get_gpg_context(edward_config.gnupghome, |
| 243 | edward_config.sign_with_key) |
| 244 | |
| 245 | email_text = sys.stdin.read() |
| 246 | email_struct = parse_pgp_mime(email_text, gpgme_ctx) |
| 247 | |
| 248 | email_to, email_from, email_subject = email_to_from_subject(email_text) |
| 249 | lang = import_lang(email_to) |
| 250 | |
| 251 | replyinfo_obj = ReplyInfo() |
| 252 | replyinfo_obj.replies = lang.replies |
| 253 | |
| 254 | prepare_for_reply(email_struct, replyinfo_obj) |
| 255 | encrypt_to_key = get_key_from_fp(replyinfo_obj, gpgme_ctx) |
| 256 | reply_plaintext = write_reply(replyinfo_obj) |
| 257 | |
| 258 | reply_mime = generate_encrypted_mime(reply_plaintext, email_from, \ |
| 259 | email_subject, encrypt_to_key, |
| 260 | gpgme_ctx) |
| 261 | |
| 262 | print(reply_mime) |
| 263 | |
| 264 | |
| 265 | def get_gpg_context (gnupghome, sign_with_key_fp): |
| 266 | """ |
| 267 | This function returns the GPG context needed for encryption and signing. |
| 268 | |
| 269 | The context is needed by other functions which use GPG functionality. |
| 270 | |
| 271 | Args: |
| 272 | gnupghome: The path to "~/.gnupg/" or its alternative. |
| 273 | sign_with_key: The fingerprint of the key to sign with |
| 274 | |
| 275 | Returns: |
| 276 | A gpgme context to be used for GPG functions. |
| 277 | |
| 278 | Post: |
| 279 | the 'armor' flag is set to True and the list of signing keys contains |
| 280 | the single specified key |
| 281 | """ |
| 282 | |
| 283 | os.environ['GNUPGHOME'] = gnupghome |
| 284 | |
| 285 | gpgme_ctx = gpgme.Context() |
| 286 | gpgme_ctx.armor = True |
| 287 | |
| 288 | try: |
| 289 | sign_with_key = gpgme_ctx.get_key(sign_with_key_fp) |
| 290 | except: |
| 291 | error("unable to load signing key. is the gnupghome " |
| 292 | + "and signing key properly set in the edward_config.py?") |
| 293 | exit(1) |
| 294 | |
| 295 | gpgme_ctx.signers = [sign_with_key] |
| 296 | |
| 297 | return gpgme_ctx |
| 298 | |
| 299 | |
| 300 | def parse_pgp_mime (email_text, gpgme_ctx): |
| 301 | """Parses the email for mime payloads and decrypts/verfies signatures. |
| 302 | |
| 303 | This function creates a representation of a mime or plaintext email with |
| 304 | the EddyMsg class. It then splits each mime payload into one or more pieces |
| 305 | which may be plain text or GPG data. It then decrypts encrypted parts and |
| 306 | does some very basic signature verification on those parts. |
| 307 | |
| 308 | Args: |
| 309 | email_text: an email message in string format |
| 310 | gpgme_ctx: a gpgme context |
| 311 | |
| 312 | Returns: |
| 313 | A message as an instance of EddyMsg |
| 314 | |
| 315 | Post: |
| 316 | the returned EddyMsg instance has split, decrypted, verified and pubkey |
| 317 | imported payloads |
| 318 | """ |
| 319 | |
| 320 | email_struct = email.parser.Parser().parsestr(email_text) |
| 321 | |
| 322 | eddymsg_obj = parse_mime(email_struct) |
| 323 | split_payloads(eddymsg_obj) |
| 324 | gpg_on_payloads(eddymsg_obj, gpgme_ctx) |
| 325 | |
| 326 | return eddymsg_obj |
| 327 | |
| 328 | |
| 329 | def parse_mime(msg_struct): |
| 330 | """Translates python's email.parser format into an EddyMsg format |
| 331 | |
| 332 | If the message is multi-part, then a recursive object is created, where |
| 333 | each sub-part is also a EddyMsg instance. |
| 334 | |
| 335 | Args: |
| 336 | msg_struct: an email parsed with email.parser.Parser(), which can be |
| 337 | multi-part |
| 338 | |
| 339 | Returns: |
| 340 | an instance of EddyMsg, potentially a recursive one. |
| 341 | """ |
| 342 | |
| 343 | eddymsg_obj = EddyMsg() |
| 344 | |
| 345 | if msg_struct.is_multipart() == True: |
| 346 | payloads = msg_struct.get_payload() |
| 347 | |
| 348 | eddymsg_obj.multipart = True |
| 349 | eddymsg_obj.subparts = list(map(parse_mime, payloads)) |
| 350 | |
| 351 | else: |
| 352 | eddymsg_obj = get_subpart_data(msg_struct) |
| 353 | |
| 354 | return eddymsg_obj |
| 355 | |
| 356 | |
| 357 | def scan_and_split (payload_piece, match_type, pattern): |
| 358 | """This splits the payloads of an EddyMsg object into GPG and text parts. |
| 359 | |
| 360 | An EddyMsg object's payload_pieces starts off as a list containing a single |
| 361 | PayloadPiece object. This function returns a list of these objects which |
| 362 | have been split into GPG data and regular text, if such splits need to be/ |
| 363 | can be made. |
| 364 | |
| 365 | Args: |
| 366 | payload_piece: a single payload or a split part of a payload |
| 367 | match_type: the type of data to try to spit out from the payload piece |
| 368 | pattern: the search pattern to be used for finding that type of data |
| 369 | |
| 370 | Returns: |
| 371 | a list of objects of the PayloadPiece class, in the order that the |
| 372 | string part of payload_piece originally was, broken up according to |
| 373 | matches specified by 'pattern'. |
| 374 | """ |
| 375 | |
| 376 | # don't try to re-split pieces containing gpg data |
| 377 | if payload_piece.piece_type != "text": |
| 378 | return [payload_piece] |
| 379 | |
| 380 | flags = re.DOTALL | re.MULTILINE |
| 381 | matches = re.search("(?P<beginning>.*?)(?P<match>" + pattern + |
| 382 | ")(?P<rest>.*)", payload_piece.string, flags=flags) |
| 383 | |
| 384 | if matches == None: |
| 385 | pieces = [payload_piece] |
| 386 | |
| 387 | else: |
| 388 | |
| 389 | beginning = PayloadPiece() |
| 390 | beginning.string = matches.group('beginning') |
| 391 | beginning.piece_type = payload_piece.piece_type |
| 392 | |
| 393 | match = PayloadPiece() |
| 394 | match.string = matches.group('match') |
| 395 | match.piece_type = match_type |
| 396 | |
| 397 | rest = PayloadPiece() |
| 398 | rest.string = matches.group('rest') |
| 399 | rest.piece_type = payload_piece.piece_type |
| 400 | |
| 401 | more_pieces = scan_and_split(rest, match_type, pattern) |
| 402 | pieces = [beginning, match ] + more_pieces |
| 403 | |
| 404 | return pieces |
| 405 | |
| 406 | |
| 407 | def get_subpart_data (part): |
| 408 | """This function grabs information from a single part mime object. |
| 409 | |
| 410 | It copies needed data from a single part email.parser.Parser() object over |
| 411 | to an EddyMsg object. |
| 412 | |
| 413 | Args: |
| 414 | part: a non-multi-part mime.parser.Parser() object |
| 415 | |
| 416 | Returns: |
| 417 | a single-part EddyMsg() object |
| 418 | """ |
| 419 | |
| 420 | obj = EddyMsg() |
| 421 | |
| 422 | obj.charset = part.get_content_charset() |
| 423 | obj.payload_bytes = part.get_payload(decode=True) |
| 424 | |
| 425 | obj.filename = part.get_filename() |
| 426 | obj.content_type = part.get_content_type() |
| 427 | obj.description_list = part['content-description'] |
| 428 | |
| 429 | # your guess is as good as a-myy-ee-ine... |
| 430 | if obj.charset == None: |
| 431 | obj.charset = 'utf-8' |
| 432 | |
| 433 | if obj.payload_bytes != None: |
| 434 | try: |
| 435 | payload = PayloadPiece() |
| 436 | payload.string = obj.payload_bytes.decode(obj.charset) |
| 437 | payload.piece_type = 'text' |
| 438 | |
| 439 | obj.payload_pieces = [payload] |
| 440 | except UnicodeDecodeError: |
| 441 | pass |
| 442 | |
| 443 | return obj |
| 444 | |
| 445 | |
| 446 | def do_to_eddys_pieces (function_to_do, eddymsg_obj, data): |
| 447 | """A function which maps another function onto a message's subparts. |
| 448 | |
| 449 | This is a higer-order function which recursively performs a specified |
| 450 | function on each subpart of a multi-part message. Each single-part sub-part |
| 451 | has the function applied to it. This function also works if the part passed |
| 452 | in is single-part. |
| 453 | |
| 454 | Args: |
| 455 | function_to_do: function to perform on sub-parts |
| 456 | eddymsg_obj: a single part or multi-part EddyMsg object |
| 457 | data: a second argument to pass to 'function_to_do' |
| 458 | |
| 459 | Returns: |
| 460 | Nothing |
| 461 | |
| 462 | Post: |
| 463 | The passed-in EddyMsg object is transformed recursively on its |
| 464 | sub-parts according to 'function_to_do'. |
| 465 | """ |
| 466 | |
| 467 | if eddymsg_obj.multipart == True: |
| 468 | for sub in eddymsg_obj.subparts: |
| 469 | do_to_eddys_pieces(function_to_do, sub, data) |
| 470 | else: |
| 471 | function_to_do(eddymsg_obj, data) |
| 472 | |
| 473 | |
| 474 | def split_payloads (eddymsg_obj): |
| 475 | """Splits all (sub-)payloads of a message into GPG data and regular text. |
| 476 | |
| 477 | Recursively performs payload splitting on all sub-parts of an EddyMsg |
| 478 | object into the various GPG data types, such as GPG messages, public key |
| 479 | blocks and signed text. |
| 480 | |
| 481 | Args: |
| 482 | eddymsg_obj: an instance of EddyMsg |
| 483 | |
| 484 | Returns: |
| 485 | Nothing |
| 486 | |
| 487 | Pre: |
| 488 | The EddyMsg object has payloads that are unsplit (by may be split).. |
| 489 | |
| 490 | Post: |
| 491 | The EddyMsg object's payloads are all split into GPG and non-GPG parts. |
| 492 | """ |
| 493 | |
| 494 | for match_type in match_types: |
| 495 | do_to_eddys_pieces(split_payload_pieces, eddymsg_obj, match_type) |
| 496 | |
| 497 | |
| 498 | def split_payload_pieces (eddymsg_obj, match_type): |
| 499 | """A helper function for split_payloads(); works on PayloadPiece objects. |
| 500 | |
| 501 | This function splits up PayloadPiece objects into multipe PayloadPiece |
| 502 | objects and replaces the EddyMsg object's previous list of payload pieces |
| 503 | with the new split up one. |
| 504 | |
| 505 | Args: |
| 506 | eddymsg_obj: a single-part EddyMsg object. |
| 507 | match_type: a tuple from the match_types list, which specifies a match |
| 508 | name and a match pattern. |
| 509 | |
| 510 | Returns: |
| 511 | Nothing |
| 512 | |
| 513 | Pre: |
| 514 | The payload piece(s) of an EddyMsg object may be already split or |
| 515 | unsplit. |
| 516 | |
| 517 | Post: |
| 518 | The EddyMsg object's payload piece(s) are split into a list of pieces |
| 519 | if matches of the match_type are found. |
| 520 | """ |
| 521 | |
| 522 | (match_name, pattern) = match_type |
| 523 | |
| 524 | new_pieces_list = [] |
| 525 | for piece in eddymsg_obj.payload_pieces: |
| 526 | new_pieces_list += scan_and_split(piece, match_name, pattern) |
| 527 | |
| 528 | eddymsg_obj.payload_pieces = new_pieces_list |
| 529 | |
| 530 | |
| 531 | def gpg_on_payloads (eddymsg_obj, gpgme_ctx, prev_parts=[]): |
| 532 | """Performs GPG operations on the GPG parts of the message |
| 533 | |
| 534 | This function decrypts text, verifies signatures, and imports public keys |
| 535 | included in an email. |
| 536 | |
| 537 | Args: |
| 538 | eddymsg_obj: an EddyMsg object with its payload_pieces split into GPG |
| 539 | and non-GPG sections by split_payloads() |
| 540 | gpgme_ctx: a gpgme context |
| 541 | |
| 542 | prev_parts: a list of mime parts that occur before the eddymsg_obj |
| 543 | part, under the same multi-part mime part. This is used for |
| 544 | verifying detached signatures. For the root mime part, this should |
| 545 | be an empty list, which is the default value if this paramater is |
| 546 | omitted. |
| 547 | |
| 548 | Return: |
| 549 | Nothing |
| 550 | |
| 551 | Pre: |
| 552 | eddymsg_obj should have its payloads split into gpg and non-gpg pieces. |
| 553 | |
| 554 | Post: |
| 555 | Decryption, verification and key imports occur. the gpg_data member of |
| 556 | PayloadPiece objects get filled in with GPGData objects. |
| 557 | """ |
| 558 | |
| 559 | if eddymsg_obj.multipart == True: |
| 560 | prev_parts=[] |
| 561 | for sub in eddymsg_obj.subparts: |
| 562 | gpg_on_payloads (sub, gpgme_ctx, prev_parts) |
| 563 | prev_parts += [sub] |
| 564 | |
| 565 | return |
| 566 | |
| 567 | for piece in eddymsg_obj.payload_pieces: |
| 568 | |
| 569 | if piece.piece_type == "text": |
| 570 | # don't transform the plaintext. |
| 571 | pass |
| 572 | |
| 573 | elif piece.piece_type == "message": |
| 574 | (plaintext, sigs) = decrypt_block(piece.string, gpgme_ctx) |
| 575 | |
| 576 | if plaintext: |
| 577 | piece.gpg_data = GPGData() |
| 578 | piece.gpg_data.decrypted = True |
| 579 | piece.gpg_data.sigs = sigs |
| 580 | # recurse! |
| 581 | piece.gpg_data.plainobj = parse_pgp_mime(plaintext, gpgme_ctx) |
| 582 | continue |
| 583 | |
| 584 | # if not encrypted, check to see if this is an armored signature. |
| 585 | (plaintext, sigs) = verify_sig_message(piece.string, gpgme_ctx) |
| 586 | |
| 587 | if plaintext: |
| 588 | piece.piece_type = "signature" |
| 589 | piece.gpg_data = GPGData() |
| 590 | piece.gpg_data.sigs = sigs |
| 591 | # recurse! |
| 592 | piece.gpg_data.plainobj = parse_pgp_mime(plaintext, gpgme_ctx) |
| 593 | |
| 594 | elif piece.piece_type == "pubkey": |
| 595 | key_fps = add_gpg_key(piece.string, gpgme_ctx) |
| 596 | |
| 597 | if key_fps != []: |
| 598 | piece.gpg_data = GPGData() |
| 599 | piece.gpg_data.keys = key_fps |
| 600 | |
| 601 | elif piece.piece_type == "clearsign": |
| 602 | (plaintext, sig_fps) = verify_clear_signature(piece.string, gpgme_ctx) |
| 603 | |
| 604 | if sig_fps != []: |
| 605 | piece.gpg_data = GPGData() |
| 606 | piece.gpg_data.sigs = sig_fps |
| 607 | piece.gpg_data.plainobj = parse_pgp_mime(plaintext, gpgme_ctx) |
| 608 | |
| 609 | elif piece.piece_type == "detachedsig": |
| 610 | for prev in prev_parts: |
| 611 | payload_bytes = prev.payload_bytes |
| 612 | sig_fps = verify_detached_signature(piece.string, payload_bytes, gpgme_ctx) |
| 613 | |
| 614 | if sig_fps != []: |
| 615 | piece.gpg_data = GPGData() |
| 616 | piece.gpg_data.sigs = sig_fps |
| 617 | piece.gpg_data.plainobj = prev |
| 618 | break |
| 619 | |
| 620 | else: |
| 621 | pass |
| 622 | |
| 623 | |
| 624 | def prepare_for_reply (eddymsg_obj, replyinfo_obj): |
| 625 | """Updates replyinfo_obj with info on the message's GPG success/failures |
| 626 | |
| 627 | This function marks replyinfo_obj with information about whether encrypted |
| 628 | text in eddymsg_obj was successfully decrypted, signatures were verified |
| 629 | and whether a public key was found or not. |
| 630 | |
| 631 | Args: |
| 632 | eddymsg_obj: a message in the EddyMsg format |
| 633 | replyinfo_obj: an instance of ReplyInfo |
| 634 | |
| 635 | Returns: |
| 636 | Nothing |
| 637 | |
| 638 | Pre: |
| 639 | eddymsg_obj has had its gpg_data created by gpg_on_payloads |
| 640 | |
| 641 | Post: |
| 642 | replyinfo_obj has been updated with info about decryption/sig |
| 643 | verififcation status, etc. However the desired key isn't imported until |
| 644 | later, so the success or failure of that updates the values set here. |
| 645 | """ |
| 646 | |
| 647 | do_to_eddys_pieces(prepare_for_reply_pieces, eddymsg_obj, replyinfo_obj) |
| 648 | |
| 649 | def prepare_for_reply_pieces (eddymsg_obj, replyinfo_obj): |
| 650 | """A helper function for prepare_for_reply |
| 651 | |
| 652 | It updates replyinfo_obj with GPG success/failure information, when |
| 653 | supplied a single-part EddyMsg object. |
| 654 | |
| 655 | Args: |
| 656 | eddymsg_obj: a single-part message in the EddyMsg format |
| 657 | replyinfo_obj: an object which holds information about the message's |
| 658 | GPG status |
| 659 | |
| 660 | Returns: |
| 661 | Nothing |
| 662 | |
| 663 | Pre: |
| 664 | eddymsg_obj is a single-part message. (it may be a part of a multi-part |
| 665 | message.) It has had its gpg_data created by gpg_on_payloads if it has |
| 666 | gpg data. |
| 667 | |
| 668 | Post: |
| 669 | replyinfo_obj has been updated with gpg success/failure information |
| 670 | """ |
| 671 | |
| 672 | for piece in eddymsg_obj.payload_pieces: |
| 673 | if piece.piece_type == "text": |
| 674 | # don't quote the plaintext part. |
| 675 | pass |
| 676 | |
| 677 | elif piece.piece_type == "message": |
| 678 | prepare_for_reply_message(piece, replyinfo_obj) |
| 679 | |
| 680 | elif piece.piece_type == "pubkey": |
| 681 | prepare_for_reply_pubkey(piece, replyinfo_obj) |
| 682 | |
| 683 | elif (piece.piece_type == "clearsign") \ |
| 684 | or (piece.piece_type == "detachedsig") \ |
| 685 | or (piece.piece_type == "signature"): |
| 686 | prepare_for_reply_sig(piece, replyinfo_obj) |
| 687 | |
| 688 | |
| 689 | def prepare_for_reply_message (piece, replyinfo_obj): |
| 690 | """Helper function for prepare_for_reply() |
| 691 | |
| 692 | This function is called when the piece_type of a payload piece is |
| 693 | "message", or GPG Message block. This should be encrypted text. If the |
| 694 | encryted block is signed, a sig will be attached to .target_key unless |
| 695 | there is already one there. |
| 696 | |
| 697 | Args: |
| 698 | piece: a PayloadPiece object. |
| 699 | replyinfo_obj: object which gets updated with decryption status, etc. |
| 700 | |
| 701 | |
| 702 | Returns: |
| 703 | Nothing |
| 704 | |
| 705 | Pre: |
| 706 | the piece.payload_piece value should be "message". |
| 707 | |
| 708 | Post: |
| 709 | replyinfo_obj gets updated with decryption status, signing status and a |
| 710 | potential signing key. |
| 711 | """ |
| 712 | |
| 713 | if piece.gpg_data == None: |
| 714 | replyinfo_obj.failed_decrypt = True |
| 715 | return |
| 716 | |
| 717 | replyinfo_obj.success_decrypt = True |
| 718 | |
| 719 | # we already have a key (and a message) |
| 720 | if replyinfo_obj.target_key != None: |
| 721 | return |
| 722 | |
| 723 | if piece.gpg_data.sigs != []: |
| 724 | replyinfo_obj.target_key = piece.gpg_data.sigs[0] |
| 725 | get_signed_part = False |
| 726 | else: |
| 727 | # only include a signed message in the reply. |
| 728 | get_signed_part = True |
| 729 | |
| 730 | replyinfo_obj.msg_to_quote = flatten_decrypted_payloads(piece.gpg_data.plainobj, get_signed_part) |
| 731 | |
| 732 | # to catch public keys in encrypted blocks |
| 733 | prepare_for_reply(piece.gpg_data.plainobj, replyinfo_obj) |
| 734 | |
| 735 | |
| 736 | def prepare_for_reply_pubkey (piece, replyinfo_obj): |
| 737 | """Helper function for prepare_for_reply(). Marks pubkey import status. |
| 738 | |
| 739 | Marks replyinfo_obj with pub key import status. |
| 740 | |
| 741 | Args: |
| 742 | piece: a PayloadPiece object |
| 743 | replyinfo_obj: a ReplyInfo object |
| 744 | |
| 745 | Pre: |
| 746 | piece.piece_type should be set to "pubkey". |
| 747 | |
| 748 | Post: |
| 749 | replyinfo_obj has its fields updated. |
| 750 | """ |
| 751 | |
| 752 | if piece.gpg_data == None or piece.gpg_data.keys == []: |
| 753 | replyinfo_obj.no_public_key = True |
| 754 | else: |
| 755 | replyinfo_obj.public_key_received = True |
| 756 | |
| 757 | if replyinfo_obj.fallback_target_key == None: |
| 758 | replyinfo_obj.fallback_target_key = piece.gpg_data.keys[0] |
| 759 | |
| 760 | |
| 761 | def prepare_for_reply_sig (piece, replyinfo_obj): |
| 762 | """Helper function for prepare_for_reply(). Marks sig verification status. |
| 763 | |
| 764 | Marks replyinfo_obj with signature verification status. |
| 765 | |
| 766 | Args: |
| 767 | piece: a PayloadPiece object |
| 768 | replyinfo_obj: a ReplyInfo object |
| 769 | |
| 770 | Pre: |
| 771 | piece.piece_type should be set to "clearsign", "signature", or |
| 772 | "detachedsig". |
| 773 | |
| 774 | Post: |
| 775 | replyinfo_obj has its fields updated. |
| 776 | """ |
| 777 | |
| 778 | if piece.gpg_data == None or piece.gpg_data.sigs == []: |
| 779 | replyinfo_obj.sig_failure = True |
| 780 | else: |
| 781 | replyinfo_obj.sig_success = True |
| 782 | |
| 783 | if replyinfo_obj.fallback_target_key == None: |
| 784 | replyinfo_obj.fallback_target_key = piece.gpg_data.sigs[0] |
| 785 | |
| 786 | |
| 787 | |
| 788 | def flatten_decrypted_payloads (eddymsg_obj, get_signed_part): |
| 789 | |
| 790 | flat_string = "" |
| 791 | |
| 792 | if eddymsg_obj == None: |
| 793 | return "" |
| 794 | |
| 795 | # recurse on multi-part mime |
| 796 | if eddymsg_obj.multipart == True: |
| 797 | for sub in eddymsg_obj.subparts: |
| 798 | flat_string += flatten_decrypted_payloads (sub, get_signed_part) |
| 799 | |
| 800 | return flat_string |
| 801 | |
| 802 | for piece in eddymsg_obj.payload_pieces: |
| 803 | if (get_signed_part): |
| 804 | # don't include nested encryption |
| 805 | if ((piece.piece_type == "clearsign") \ |
| 806 | or (piece.piece_type == "detachedsig") \ |
| 807 | or (piece.piece_type == "signature")) \ |
| 808 | and (piece.gpg_data != None): |
| 809 | # FIXME: the key used to sign this message needs to be the one that is used for the encrypted reply. |
| 810 | flat_string += flatten_decrypted_payloads (piece.gpg_data.plainobj, False) |
| 811 | break |
| 812 | else: |
| 813 | if piece.piece_type == "text": |
| 814 | flat_string += piece.string |
| 815 | |
| 816 | return flat_string |
| 817 | |
| 818 | |
| 819 | def get_key_from_fp (replyinfo_obj, gpgme_ctx): |
| 820 | |
| 821 | if replyinfo_obj.target_key == None: |
| 822 | replyinfo_obj.target_key = replyinfo_obj.fallback_target_key |
| 823 | |
| 824 | if replyinfo_obj.target_key != None: |
| 825 | try: |
| 826 | encrypt_to_key = gpgme_ctx.get_key(replyinfo_obj.target_key) |
| 827 | return encrypt_to_key |
| 828 | |
| 829 | except: |
| 830 | pass |
| 831 | |
| 832 | # no available key to use |
| 833 | replyinfo_obj.target_key = None |
| 834 | replyinfo_obj.fallback_target_key = None |
| 835 | |
| 836 | replyinfo_obj.no_public_key = True |
| 837 | replyinfo_obj.public_key_received = False |
| 838 | |
| 839 | return None |
| 840 | |
| 841 | |
| 842 | def write_reply (replyinfo_obj): |
| 843 | |
| 844 | reply_plain = "" |
| 845 | |
| 846 | if replyinfo_obj.success_decrypt == True: |
| 847 | reply_plain += replyinfo_obj.replies['success_decrypt'] |
| 848 | |
| 849 | if replyinfo_obj.no_public_key == False: |
| 850 | quoted_text = email_quote_text(replyinfo_obj.msg_to_quote) |
| 851 | reply_plain += quoted_text |
| 852 | |
| 853 | elif replyinfo_obj.failed_decrypt == True: |
| 854 | reply_plain += replyinfo_obj.replies['failed_decrypt'] |
| 855 | |
| 856 | |
| 857 | if replyinfo_obj.sig_success == True: |
| 858 | reply_plain += "\n\n" |
| 859 | reply_plain += replyinfo_obj.replies['sig_success'] |
| 860 | |
| 861 | elif replyinfo_obj.sig_failure == True: |
| 862 | reply_plain += "\n\n" |
| 863 | reply_plain += replyinfo_obj.replies['sig_failure'] |
| 864 | |
| 865 | |
| 866 | if replyinfo_obj.public_key_received == True: |
| 867 | reply_plain += "\n\n" |
| 868 | reply_plain += replyinfo_obj.replies['public_key_received'] |
| 869 | |
| 870 | elif replyinfo_obj.no_public_key == True: |
| 871 | reply_plain += "\n\n" |
| 872 | reply_plain += replyinfo_obj.replies['no_public_key'] |
| 873 | |
| 874 | |
| 875 | reply_plain += "\n\n" |
| 876 | reply_plain += replyinfo_obj.replies['signature'] |
| 877 | |
| 878 | return reply_plain |
| 879 | |
| 880 | |
| 881 | def add_gpg_key (key_block, gpgme_ctx): |
| 882 | |
| 883 | fp = io.BytesIO(key_block.encode('ascii')) |
| 884 | |
| 885 | result = gpgme_ctx.import_(fp) |
| 886 | imports = result.imports |
| 887 | |
| 888 | key_fingerprints = [] |
| 889 | |
| 890 | if imports != []: |
| 891 | for import_ in imports: |
| 892 | fingerprint = import_[0] |
| 893 | key_fingerprints += [fingerprint] |
| 894 | |
| 895 | debug("added gpg key: " + fingerprint) |
| 896 | |
| 897 | return key_fingerprints |
| 898 | |
| 899 | |
| 900 | def verify_sig_message (msg_block, gpgme_ctx): |
| 901 | |
| 902 | block_b = io.BytesIO(msg_block.encode('ascii')) |
| 903 | plain_b = io.BytesIO() |
| 904 | |
| 905 | try: |
| 906 | sigs = gpgme_ctx.verify(block_b, None, plain_b) |
| 907 | except: |
| 908 | return ("",[]) |
| 909 | |
| 910 | plaintext = plain_b.getvalue().decode('utf-8') |
| 911 | |
| 912 | fingerprints = [] |
| 913 | for sig in sigs: |
| 914 | fingerprints += [sig.fpr] |
| 915 | return (plaintext, fingerprints) |
| 916 | |
| 917 | |
| 918 | def verify_clear_signature (sig_block, gpgme_ctx): |
| 919 | |
| 920 | # FIXME: this might require the un-decoded bytes |
| 921 | # or the correct re-encoding with the carset of the mime part. |
| 922 | msg_fp = io.BytesIO(sig_block.encode('utf-8')) |
| 923 | ptxt_fp = io.BytesIO() |
| 924 | |
| 925 | result = gpgme_ctx.verify(msg_fp, None, ptxt_fp) |
| 926 | |
| 927 | # FIXME: this might require using the charset of the mime part. |
| 928 | plaintext = ptxt_fp.getvalue().decode('utf-8') |
| 929 | |
| 930 | sig_fingerprints = [] |
| 931 | for res_ in result: |
| 932 | sig_fingerprints += [res_.fpr] |
| 933 | |
| 934 | return plaintext, sig_fingerprints |
| 935 | |
| 936 | |
| 937 | def verify_detached_signature (detached_sig, plaintext_bytes, gpgme_ctx): |
| 938 | |
| 939 | detached_sig_fp = io.BytesIO(detached_sig.encode('ascii')) |
| 940 | plaintext_fp = io.BytesIO(plaintext_bytes) |
| 941 | ptxt_fp = io.BytesIO() |
| 942 | |
| 943 | result = gpgme_ctx.verify(detached_sig_fp, plaintext_fp, None) |
| 944 | |
| 945 | sig_fingerprints = [] |
| 946 | for res_ in result: |
| 947 | sig_fingerprints += [res_.fpr] |
| 948 | |
| 949 | return sig_fingerprints |
| 950 | |
| 951 | |
| 952 | def decrypt_block (msg_block, gpgme_ctx): |
| 953 | |
| 954 | block_b = io.BytesIO(msg_block.encode('ascii')) |
| 955 | plain_b = io.BytesIO() |
| 956 | |
| 957 | try: |
| 958 | sigs = gpgme_ctx.decrypt_verify(block_b, plain_b) |
| 959 | except: |
| 960 | return ("",[]) |
| 961 | |
| 962 | plaintext = plain_b.getvalue().decode('utf-8') |
| 963 | |
| 964 | fingerprints = [] |
| 965 | for sig in sigs: |
| 966 | fingerprints += [sig.fpr] |
| 967 | return (plaintext, fingerprints) |
| 968 | |
| 969 | |
| 970 | def choose_reply_encryption_key (gpgme_ctx, fingerprints): |
| 971 | |
| 972 | reply_key = None |
| 973 | for fp in fingerprints: |
| 974 | try: |
| 975 | key = gpgme_ctx.get_key(fp) |
| 976 | |
| 977 | if (key.can_encrypt == True): |
| 978 | reply_key = key |
| 979 | break |
| 980 | except: |
| 981 | continue |
| 982 | |
| 983 | |
| 984 | return reply_key |
| 985 | |
| 986 | |
| 987 | def email_to_from_subject (email_text): |
| 988 | |
| 989 | email_struct = email.parser.Parser().parsestr(email_text) |
| 990 | |
| 991 | email_to = email_struct['To'] |
| 992 | email_from = email_struct['From'] |
| 993 | email_subject = email_struct['Subject'] |
| 994 | |
| 995 | return email_to, email_from, email_subject |
| 996 | |
| 997 | |
| 998 | def import_lang(email_to): |
| 999 | |
| 1000 | if email_to != None: |
| 1001 | for lang in langs: |
| 1002 | if "edward-" + lang in email_to: |
| 1003 | lang = "lang." + re.sub('-', '_', lang) |
| 1004 | language = importlib.import_module(lang) |
| 1005 | |
| 1006 | return language |
| 1007 | |
| 1008 | return importlib.import_module("lang.en") |
| 1009 | |
| 1010 | |
| 1011 | def generate_encrypted_mime (plaintext, email_from, email_subject, encrypt_to_key, |
| 1012 | gpgme_ctx): |
| 1013 | |
| 1014 | # quoted printable encoding lets most ascii characters look normal |
| 1015 | # before the mime message is decoded. |
| 1016 | char_set = email.charset.Charset("utf-8") |
| 1017 | char_set.body_encoding = email.charset.QP |
| 1018 | |
| 1019 | # MIMEText doesn't allow setting the text encoding |
| 1020 | # so we use MIMENonMultipart. |
| 1021 | plaintext_mime = MIMENonMultipart('text', 'plain') |
| 1022 | plaintext_mime.set_payload(plaintext, charset=char_set) |
| 1023 | |
| 1024 | if (encrypt_to_key != None): |
| 1025 | |
| 1026 | encrypted_text = encrypt_sign_message(plaintext_mime.as_string(), |
| 1027 | encrypt_to_key, |
| 1028 | gpgme_ctx) |
| 1029 | |
| 1030 | control_mime = MIMEApplication("Version: 1", |
| 1031 | _subtype='pgp-encrypted', |
| 1032 | _encoder=email.encoders.encode_7or8bit) |
| 1033 | control_mime['Content-Description'] = 'PGP/MIME version identification' |
| 1034 | control_mime.set_charset('us-ascii') |
| 1035 | |
| 1036 | encoded_mime = MIMEApplication(encrypted_text, |
| 1037 | _subtype='octet-stream; name="encrypted.asc"', |
| 1038 | _encoder=email.encoders.encode_7or8bit) |
| 1039 | encoded_mime['Content-Description'] = 'OpenPGP encrypted message' |
| 1040 | encoded_mime['Content-Disposition'] = 'inline; filename="encrypted.asc"' |
| 1041 | encoded_mime.set_charset('us-ascii') |
| 1042 | |
| 1043 | message_mime = MIMEMultipart(_subtype="encrypted", protocol="application/pgp-encrypted") |
| 1044 | message_mime.attach(control_mime) |
| 1045 | message_mime.attach(encoded_mime) |
| 1046 | message_mime['Content-Disposition'] = 'inline' |
| 1047 | |
| 1048 | else: |
| 1049 | message_mime = plaintext_mime |
| 1050 | |
| 1051 | message_mime['To'] = email_from |
| 1052 | message_mime['Subject'] = email_subject |
| 1053 | |
| 1054 | reply = message_mime.as_string() |
| 1055 | |
| 1056 | return reply |
| 1057 | |
| 1058 | |
| 1059 | def email_quote_text (text): |
| 1060 | |
| 1061 | quoted_message = re.sub(r'^', r'> ', text, flags=re.MULTILINE) |
| 1062 | |
| 1063 | return quoted_message |
| 1064 | |
| 1065 | |
| 1066 | def encrypt_sign_message (plaintext, encrypt_to_key, gpgme_ctx): |
| 1067 | |
| 1068 | plaintext_bytes = io.BytesIO(plaintext.encode('ascii')) |
| 1069 | encrypted_bytes = io.BytesIO() |
| 1070 | |
| 1071 | gpgme_ctx.encrypt_sign([encrypt_to_key], gpgme.ENCRYPT_ALWAYS_TRUST, |
| 1072 | plaintext_bytes, encrypted_bytes) |
| 1073 | |
| 1074 | encrypted_txt = encrypted_bytes.getvalue().decode('ascii') |
| 1075 | return encrypted_txt |
| 1076 | |
| 1077 | |
| 1078 | def error (error_msg): |
| 1079 | |
| 1080 | sys.stderr.write(progname + ": " + str(error_msg) + "\n") |
| 1081 | |
| 1082 | |
| 1083 | def debug (debug_msg): |
| 1084 | |
| 1085 | if edward_config.debug == True: |
| 1086 | error(debug_msg) |
| 1087 | |
| 1088 | |
| 1089 | def handle_args (): |
| 1090 | |
| 1091 | global progname |
| 1092 | progname = sys.argv[0] |
| 1093 | |
| 1094 | if len(sys.argv) > 1: |
| 1095 | print(progname + ": error, this program doesn't " \ |
| 1096 | "need any arguments.", file=sys.stderr) |
| 1097 | exit(1) |
| 1098 | |
| 1099 | |
| 1100 | if __name__ == "__main__": |
| 1101 | |
| 1102 | main() |
| 1103 | |