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0bec96d6 | 1 | #! /usr/bin/env python3 |
ff4136c7 | 2 | # -*- coding: utf-8 -*- |
0bec96d6 AE |
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+) * | |
8bdfb6d4 AE |
20 | * Copyright (C) 2009-2015 Tails developers <tails@boum.org> ( GPLv3+) * |
21 | * Copyright (C) 2009 W. Trevor King <wking@drexel.edu> ( GPLv2+) * | |
0bec96d6 AE |
22 | * * |
23 | * Special thanks to Josh Drake for writing the original edward bot! :) * | |
24 | * * | |
25 | ************************************************************************ | |
26 | ||
a5385c04 | 27 | Code sourced from these projects: |
0bec96d6 | 28 | |
8bdfb6d4 AE |
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 | |
0bec96d6 AE |
32 | """ |
33 | ||
0bec96d6 AE |
34 | import re |
35 | import io | |
40c37ab3 | 36 | import os |
2f4ce2b2 | 37 | import sys |
0fd3389f | 38 | import enum |
2f4ce2b2 | 39 | import gpgme |
adcef2f7 | 40 | import importlib |
0bec96d6 | 41 | |
8bdfb6d4 AE |
42 | import email.parser |
43 | import email.message | |
44 | import email.encoders | |
45 | ||
46 | from email.mime.multipart import MIMEMultipart | |
47 | from email.mime.application import MIMEApplication | |
48 | from email.mime.nonmultipart import MIMENonMultipart | |
49 | ||
40c37ab3 | 50 | import edward_config |
c96f3837 | 51 | |
5b0e37d3 | 52 | langs = ["de", "el", "en", "fr", "ja", "pt-br", "ro", "ru", "tr"] |
adcef2f7 | 53 | |
def9196c AE |
54 | """This list contains the abbreviated names of reply languages available to |
55 | edward.""" | |
56 | ||
0fd3389f AE |
57 | class TxtType (enum.Enum): |
58 | text = 0 | |
59 | message = 1 | |
60 | pubkey = 2 | |
61 | detachedsig = 3 | |
62 | signature = 4 | |
def9196c | 63 | |
0fd3389f | 64 | |
2f4102b9 | 65 | match_pairs = [(TxtType.message, |
56578eaf | 66 | '-----BEGIN PGP MESSAGE-----.*?-----END PGP MESSAGE-----'), |
0fd3389f | 67 | (TxtType.pubkey, |
56578eaf | 68 | '-----BEGIN PGP PUBLIC KEY BLOCK-----.*?-----END PGP PUBLIC KEY BLOCK-----'), |
0fd3389f | 69 | (TxtType.detachedsig, |
38738401 | 70 | '-----BEGIN PGP SIGNATURE-----.*?-----END PGP SIGNATURE-----')] |
56578eaf | 71 | |
def9196c AE |
72 | """This list of tuples matches query names with re.search() queries used |
73 | to find GPG data for edward to process.""" | |
74 | ||
56578eaf AE |
75 | |
76 | class EddyMsg (object): | |
def9196c AE |
77 | """ |
78 | The EddyMsg class represents relevant parts of a mime message. | |
79 | ||
80 | The represented message can be single-part or multi-part. | |
81 | ||
82 | 'multipart' is set to True if there are multiple mime parts. | |
83 | ||
84 | 'subparts' points to a list of mime sub-parts if it is a multi-part | |
85 | message. Otherwise it points to an empty list. | |
86 | ||
6d8faaa7 AE |
87 | 'payload_bytes' is a binary representation of the mime part before header |
88 | removal and message decoding. | |
def9196c AE |
89 | |
90 | 'payload_pieces' is a list of objects containing strings that when strung | |
91 | together form the fully-decoded string representation of the mime part. | |
92 | ||
def9196c AE |
93 | The 'filename', 'content_type' and 'description_list' come from the mime |
94 | part parameters. | |
95 | """ | |
96 | ||
7d0b91d2 AE |
97 | multipart = False |
98 | subparts = [] | |
56578eaf | 99 | |
7d0b91d2 AE |
100 | payload_bytes = None |
101 | payload_pieces = [] | |
56578eaf | 102 | |
7d0b91d2 AE |
103 | filename = None |
104 | content_type = None | |
105 | description_list = None | |
56578eaf AE |
106 | |
107 | ||
108 | class PayloadPiece (object): | |
def9196c AE |
109 | """ |
110 | PayloadPiece represents a complte or sub-section of a mime part. | |
111 | ||
112 | Instances of this class are often strung together within one or more arrays | |
113 | pointed to by each instance of the EddyMsg class. | |
114 | ||
0fd3389f AE |
115 | 'piece_type' refers to an enum whose value describes the content of |
116 | 'string'. Examples include TxtType.pubkey, for public keys, and | |
117 | TxtType.message, for encrypted data (or armored signatures until they are | |
118 | known to be such.) Some of the names derive from the header and footer of | |
119 | each of these ascii-encoded gpg blocks. | |
def9196c AE |
120 | |
121 | 'string' contains some string of text, such as non-GPG text, an encrypted | |
122 | block of text, a signature, or a public key. | |
123 | ||
124 | 'gpg_data' points to any instances of GPGData that have been created based | |
125 | on the contents of 'string'. | |
126 | """ | |
127 | ||
7d0b91d2 AE |
128 | piece_type = None |
129 | string = None | |
130 | gpg_data = None | |
56578eaf AE |
131 | |
132 | ||
38738401 | 133 | class GPGData (object): |
def9196c AE |
134 | """ |
135 | GPGData holds info from decryption, sig. verification, and/or pub. keys. | |
136 | ||
137 | Instances of this class contain decrypted information, signature | |
138 | fingerprints and/or fingerprints of processed and imported public keys. | |
139 | ||
140 | 'decrypted' is set to True if 'plainobj' was created from encrypted data. | |
141 | ||
142 | 'plainobj' points to any decrypted, or signed part of, a GPG signature. It | |
143 | is intended to be an instance of the EddyMsg class. | |
144 | ||
145 | 'sigs' is a list of fingerprints of keys used to sign the data in plainobj. | |
146 | ||
147 | 'keys' is a list of fingerprints of keys obtained in public key blocks. | |
148 | """ | |
149 | ||
7d0b91d2 AE |
150 | decrypted = False |
151 | ||
152 | plainobj = None | |
153 | sigs = [] | |
154 | keys = [] | |
38738401 | 155 | |
38738401 | 156 | |
d873ff48 | 157 | class ReplyInfo (object): |
def9196c AE |
158 | """ |
159 | ReplyInfo contains details that edward uses in generating its reply. | |
160 | ||
161 | Instances of this class contain information about whether a message was | |
162 | successfully encrypted or signed, and whether a public key was attached, or | |
163 | retrievable, from the local GPG store. It stores the fingerprints of | |
164 | potential encryption key candidates and the message (if any at all) to | |
165 | quote in edward's reply. | |
166 | ||
167 | 'replies' points one of the dictionaries of translated replies. | |
168 | ||
169 | 'target_key' refers to the fingerprint of a key used to sign encrypted | |
170 | data. This is the preferred key, if it is set, and if is available. | |
171 | ||
172 | 'fallback_target_key' referst to the fingerprint of a key used to sign | |
173 | unencrypted data; alternatively it may be a public key attached to the | |
174 | message. | |
175 | ||
176 | 'msg_to_quote' refers to the part of a message which edward should quote in | |
177 | his reply. This should remain as None if there was no encrypted and singed | |
178 | part. This is to avoid making edward a service for decrypting other | |
179 | people's messages to edward. | |
180 | ||
181 | 'success_decrypt' is set to True if edward could decrypt part of the | |
182 | message. | |
183 | ||
184 | 'failed_decrypt' is set to True if edward failed to decrypt part of the | |
185 | message. | |
186 | ||
187 | 'publick_key_received' is set to True if edward successfully imported a | |
188 | public key. | |
189 | ||
190 | 'no_public_key' is set to True if edward doesn't have a key to encrypt to | |
191 | when replying to the user. | |
192 | ||
193 | 'sig_success' is set to True if edward could to some extent verify the | |
194 | signature of a signed part of the message to edward. | |
195 | ||
196 | 'sig_failure' is set to True if edward failed to some extent verify the | |
197 | signature of a signed part of the message to edward. | |
198 | """ | |
199 | ||
7d0b91d2 | 200 | replies = None |
6906d46d | 201 | |
7d0b91d2 AE |
202 | target_key = None |
203 | fallback_target_key = None | |
204 | msg_to_quote = "" | |
d873ff48 | 205 | |
7d0b91d2 AE |
206 | success_decrypt = False |
207 | failed_decrypt = False | |
208 | public_key_received = False | |
209 | no_public_key = False | |
210 | sig_success = False | |
211 | sig_failure = False | |
d873ff48 | 212 | |
38738401 | 213 | |
0bec96d6 AE |
214 | def main (): |
215 | ||
def9196c AE |
216 | """ |
217 | This is the main function for edward, a GPG reply bot. | |
218 | ||
219 | Edward responds to GPG-encrypted and signed mail, encrypting and signing | |
220 | the response if the user's public key is, or was, included in the message. | |
221 | ||
222 | Args: | |
223 | None | |
224 | ||
225 | Returns: | |
a3d6aff8 | 226 | Nothing |
def9196c AE |
227 | |
228 | Pre: | |
229 | Mime or plaintext email passing in through standard input. Portions of | |
230 | the email may be encrypted. If the To: address contains the text | |
231 | "edward-ja", then the reply will contain a reply written in the | |
232 | Japanese language. There are other languages as well. The default | |
233 | language is English. | |
234 | ||
235 | Post: | |
236 | A reply email will be printed to standard output. The contents of the | |
237 | reply email depends on whether the original email was encrypted or not, | |
238 | has or doesn't have a signature, whether a public key used in the | |
239 | original message is provided or locally stored, and the language | |
240 | implied by the To: address in the original email. | |
241 | """ | |
242 | ||
20f6e7c5 | 243 | handle_args() |
0bec96d6 | 244 | |
0a064403 AE |
245 | gpgme_ctx = get_gpg_context(edward_config.gnupghome, |
246 | edward_config.sign_with_key) | |
247 | ||
c96f3837 | 248 | email_text = sys.stdin.read() |
adcef2f7 AE |
249 | email_struct = parse_pgp_mime(email_text, gpgme_ctx) |
250 | ||
251 | email_to, email_from, email_subject = email_to_from_subject(email_text) | |
252 | lang = import_lang(email_to) | |
fafa21c3 | 253 | |
d873ff48 AE |
254 | replyinfo_obj = ReplyInfo() |
255 | replyinfo_obj.replies = lang.replies | |
256 | ||
257 | prepare_for_reply(email_struct, replyinfo_obj) | |
013f7cb8 | 258 | encrypt_to_key = get_key_from_fp(replyinfo_obj, gpgme_ctx) |
d873ff48 | 259 | reply_plaintext = write_reply(replyinfo_obj) |
adcef2f7 | 260 | |
2007103e AE |
261 | reply_mime = generate_encrypted_mime(reply_plaintext, email_from, \ |
262 | email_subject, encrypt_to_key, | |
263 | gpgme_ctx) | |
1fccb295 | 264 | |
2007103e | 265 | print(reply_mime) |
c96f3837 | 266 | |
0bec96d6 | 267 | |
0a064403 | 268 | def get_gpg_context (gnupghome, sign_with_key_fp): |
a3d6aff8 AE |
269 | """ |
270 | This function returns the GPG context needed for encryption and signing. | |
271 | ||
272 | The context is needed by other functions which use GPG functionality. | |
273 | ||
274 | Args: | |
275 | gnupghome: The path to "~/.gnupg/" or its alternative. | |
276 | sign_with_key: The fingerprint of the key to sign with | |
277 | ||
278 | Returns: | |
279 | A gpgme context to be used for GPG functions. | |
280 | ||
281 | Post: | |
282 | the 'armor' flag is set to True and the list of signing keys contains | |
283 | the single specified key | |
284 | """ | |
0a064403 AE |
285 | |
286 | os.environ['GNUPGHOME'] = gnupghome | |
287 | ||
288 | gpgme_ctx = gpgme.Context() | |
289 | gpgme_ctx.armor = True | |
290 | ||
291 | try: | |
292 | sign_with_key = gpgme_ctx.get_key(sign_with_key_fp) | |
5f6f32b1 | 293 | except gpgme.GpgmeError: |
0a064403 AE |
294 | error("unable to load signing key. is the gnupghome " |
295 | + "and signing key properly set in the edward_config.py?") | |
296 | exit(1) | |
297 | ||
298 | gpgme_ctx.signers = [sign_with_key] | |
299 | ||
300 | return gpgme_ctx | |
301 | ||
302 | ||
38738401 | 303 | def parse_pgp_mime (email_text, gpgme_ctx): |
a3d6aff8 AE |
304 | """Parses the email for mime payloads and decrypts/verfies signatures. |
305 | ||
306 | This function creates a representation of a mime or plaintext email with | |
307 | the EddyMsg class. It then splits each mime payload into one or more pieces | |
308 | which may be plain text or GPG data. It then decrypts encrypted parts and | |
309 | does some very basic signature verification on those parts. | |
310 | ||
311 | Args: | |
312 | email_text: an email message in string format | |
313 | gpgme_ctx: a gpgme context | |
314 | ||
315 | Returns: | |
316 | A message as an instance of EddyMsg | |
317 | ||
318 | Post: | |
319 | the returned EddyMsg instance has split, decrypted, verified and pubkey | |
320 | imported payloads | |
321 | """ | |
394a1476 AE |
322 | |
323 | email_struct = email.parser.Parser().parsestr(email_text) | |
324 | ||
928e3819 AE |
325 | eddymsg_obj = parse_mime(email_struct) |
326 | split_payloads(eddymsg_obj) | |
327 | gpg_on_payloads(eddymsg_obj, gpgme_ctx) | |
8bb4b0d5 | 328 | |
928e3819 | 329 | return eddymsg_obj |
0bec96d6 | 330 | |
0bec96d6 | 331 | |
56578eaf | 332 | def parse_mime(msg_struct): |
a3d6aff8 AE |
333 | """Translates python's email.parser format into an EddyMsg format |
334 | ||
335 | If the message is multi-part, then a recursive object is created, where | |
336 | each sub-part is also a EddyMsg instance. | |
337 | ||
338 | Args: | |
339 | msg_struct: an email parsed with email.parser.Parser(), which can be | |
340 | multi-part | |
341 | ||
342 | Returns: | |
343 | an instance of EddyMsg, potentially a recursive one. | |
344 | """ | |
0bec96d6 | 345 | |
928e3819 | 346 | eddymsg_obj = EddyMsg() |
8bb4b0d5 | 347 | |
56578eaf AE |
348 | if msg_struct.is_multipart() == True: |
349 | payloads = msg_struct.get_payload() | |
0bec96d6 | 350 | |
928e3819 AE |
351 | eddymsg_obj.multipart = True |
352 | eddymsg_obj.subparts = list(map(parse_mime, payloads)) | |
dd11a483 | 353 | |
56578eaf | 354 | else: |
928e3819 | 355 | eddymsg_obj = get_subpart_data(msg_struct) |
394a1476 | 356 | |
928e3819 | 357 | return eddymsg_obj |
c267c233 | 358 | |
80119cab | 359 | |
2f4102b9 | 360 | def scan_and_split (payload_piece, match_name, pattern): |
a3d6aff8 AE |
361 | """This splits the payloads of an EddyMsg object into GPG and text parts. |
362 | ||
363 | An EddyMsg object's payload_pieces starts off as a list containing a single | |
364 | PayloadPiece object. This function returns a list of these objects which | |
365 | have been split into GPG data and regular text, if such splits need to be/ | |
366 | can be made. | |
367 | ||
368 | Args: | |
369 | payload_piece: a single payload or a split part of a payload | |
2f4102b9 | 370 | match_name: the type of data to try to spit out from the payload piece |
a3d6aff8 AE |
371 | pattern: the search pattern to be used for finding that type of data |
372 | ||
373 | Returns: | |
374 | a list of objects of the PayloadPiece class, in the order that the | |
375 | string part of payload_piece originally was, broken up according to | |
376 | matches specified by 'pattern'. | |
377 | """ | |
cf75de65 | 378 | |
a5d37d44 | 379 | # don't try to re-split pieces containing gpg data |
0fd3389f | 380 | if payload_piece.piece_type != TxtType.text: |
a5d37d44 AE |
381 | return [payload_piece] |
382 | ||
56578eaf AE |
383 | flags = re.DOTALL | re.MULTILINE |
384 | matches = re.search("(?P<beginning>.*?)(?P<match>" + pattern + | |
385 | ")(?P<rest>.*)", payload_piece.string, flags=flags) | |
86663388 | 386 | |
56578eaf AE |
387 | if matches == None: |
388 | pieces = [payload_piece] | |
c96f3837 | 389 | |
56578eaf | 390 | else: |
d437f8b2 | 391 | |
56578eaf AE |
392 | beginning = PayloadPiece() |
393 | beginning.string = matches.group('beginning') | |
394 | beginning.piece_type = payload_piece.piece_type | |
d437f8b2 | 395 | |
56578eaf AE |
396 | match = PayloadPiece() |
397 | match.string = matches.group('match') | |
2f4102b9 | 398 | match.piece_type = match_name |
d437f8b2 | 399 | |
56578eaf AE |
400 | rest = PayloadPiece() |
401 | rest.string = matches.group('rest') | |
402 | rest.piece_type = payload_piece.piece_type | |
d437f8b2 | 403 | |
2f4102b9 | 404 | more_pieces = scan_and_split(rest, match_name, pattern) |
4615b156 | 405 | pieces = [beginning, match ] + more_pieces |
d437f8b2 | 406 | |
56578eaf | 407 | return pieces |
d437f8b2 | 408 | |
d437f8b2 | 409 | |
56578eaf | 410 | def get_subpart_data (part): |
a3d6aff8 AE |
411 | """This function grabs information from a single part mime object. |
412 | ||
413 | It copies needed data from a single part email.parser.Parser() object over | |
414 | to an EddyMsg object. | |
415 | ||
416 | Args: | |
417 | part: a non-multi-part mime.parser.Parser() object | |
418 | ||
419 | Returns: | |
420 | a single-part EddyMsg() object | |
421 | """ | |
0bec96d6 | 422 | |
6d8faaa7 AE |
423 | charset = part.get_content_charset() |
424 | mime_decoded_bytes = part.get_payload(decode=True) | |
0bec96d6 | 425 | |
6d8faaa7 AE |
426 | obj = EddyMsg() |
427 | obj.payload_bytes = part.as_bytes() | |
56578eaf AE |
428 | |
429 | obj.filename = part.get_filename() | |
430 | obj.content_type = part.get_content_type() | |
431 | obj.description_list = part['content-description'] | |
432 | ||
433 | # your guess is as good as a-myy-ee-ine... | |
6d8faaa7 AE |
434 | if charset == None: |
435 | charset = 'utf-8' | |
56578eaf | 436 | |
6d8faaa7 | 437 | if mime_decoded_bytes != None: |
0eb75d9c AE |
438 | try: |
439 | payload = PayloadPiece() | |
6d8faaa7 | 440 | payload.string = mime_decoded_bytes.decode(charset) |
0fd3389f | 441 | payload.piece_type = TxtType.text |
0eb75d9c AE |
442 | |
443 | obj.payload_pieces = [payload] | |
444 | except UnicodeDecodeError: | |
445 | pass | |
56578eaf AE |
446 | |
447 | return obj | |
448 | ||
449 | ||
928e3819 | 450 | def do_to_eddys_pieces (function_to_do, eddymsg_obj, data): |
a3d6aff8 AE |
451 | """A function which maps another function onto a message's subparts. |
452 | ||
453 | This is a higer-order function which recursively performs a specified | |
454 | function on each subpart of a multi-part message. Each single-part sub-part | |
455 | has the function applied to it. This function also works if the part passed | |
456 | in is single-part. | |
457 | ||
458 | Args: | |
459 | function_to_do: function to perform on sub-parts | |
460 | eddymsg_obj: a single part or multi-part EddyMsg object | |
461 | data: a second argument to pass to 'function_to_do' | |
462 | ||
463 | Returns: | |
464 | Nothing | |
465 | ||
466 | Post: | |
467 | The passed-in EddyMsg object is transformed recursively on its | |
468 | sub-parts according to 'function_to_do'. | |
469 | """ | |
56578eaf | 470 | |
928e3819 AE |
471 | if eddymsg_obj.multipart == True: |
472 | for sub in eddymsg_obj.subparts: | |
d873ff48 | 473 | do_to_eddys_pieces(function_to_do, sub, data) |
394a1476 | 474 | else: |
928e3819 | 475 | function_to_do(eddymsg_obj, data) |
dd11a483 AE |
476 | |
477 | ||
928e3819 | 478 | def split_payloads (eddymsg_obj): |
a3d6aff8 AE |
479 | """Splits all (sub-)payloads of a message into GPG data and regular text. |
480 | ||
481 | Recursively performs payload splitting on all sub-parts of an EddyMsg | |
482 | object into the various GPG data types, such as GPG messages, public key | |
483 | blocks and signed text. | |
484 | ||
485 | Args: | |
486 | eddymsg_obj: an instance of EddyMsg | |
487 | ||
488 | Returns: | |
489 | Nothing | |
490 | ||
491 | Pre: | |
492 | The EddyMsg object has payloads that are unsplit (by may be split).. | |
493 | ||
494 | Post: | |
495 | The EddyMsg object's payloads are all split into GPG and non-GPG parts. | |
496 | """ | |
a5d37d44 | 497 | |
2f4102b9 AE |
498 | for match_pair in match_pairs: |
499 | do_to_eddys_pieces(split_payload_pieces, eddymsg_obj, match_pair) | |
a5d37d44 | 500 | |
a5d37d44 | 501 | |
2f4102b9 | 502 | def split_payload_pieces (eddymsg_obj, match_pair): |
a3d6aff8 AE |
503 | """A helper function for split_payloads(); works on PayloadPiece objects. |
504 | ||
505 | This function splits up PayloadPiece objects into multipe PayloadPiece | |
506 | objects and replaces the EddyMsg object's previous list of payload pieces | |
507 | with the new split up one. | |
508 | ||
509 | Args: | |
510 | eddymsg_obj: a single-part EddyMsg object. | |
2f4102b9 | 511 | match_pair: a tuple from the match_pairs list, which specifies a match |
a3d6aff8 AE |
512 | name and a match pattern. |
513 | ||
514 | Returns: | |
515 | Nothing | |
516 | ||
517 | Pre: | |
518 | The payload piece(s) of an EddyMsg object may be already split or | |
519 | unsplit. | |
520 | ||
521 | Post: | |
522 | The EddyMsg object's payload piece(s) are split into a list of pieces | |
2f4102b9 | 523 | if matches of the match_pair are found. |
a3d6aff8 | 524 | """ |
a5d37d44 | 525 | |
2f4102b9 | 526 | (match_name, pattern) = match_pair |
a5d37d44 AE |
527 | |
528 | new_pieces_list = [] | |
928e3819 | 529 | for piece in eddymsg_obj.payload_pieces: |
a5d37d44 AE |
530 | new_pieces_list += scan_and_split(piece, match_name, pattern) |
531 | ||
928e3819 | 532 | eddymsg_obj.payload_pieces = new_pieces_list |
a5d37d44 AE |
533 | |
534 | ||
928e3819 | 535 | def gpg_on_payloads (eddymsg_obj, gpgme_ctx, prev_parts=[]): |
a3d6aff8 AE |
536 | """Performs GPG operations on the GPG parts of the message |
537 | ||
538 | This function decrypts text, verifies signatures, and imports public keys | |
539 | included in an email. | |
540 | ||
541 | Args: | |
542 | eddymsg_obj: an EddyMsg object with its payload_pieces split into GPG | |
543 | and non-GPG sections by split_payloads() | |
544 | gpgme_ctx: a gpgme context | |
545 | ||
546 | prev_parts: a list of mime parts that occur before the eddymsg_obj | |
547 | part, under the same multi-part mime part. This is used for | |
548 | verifying detached signatures. For the root mime part, this should | |
549 | be an empty list, which is the default value if this paramater is | |
550 | omitted. | |
551 | ||
552 | Return: | |
553 | Nothing | |
554 | ||
555 | Pre: | |
556 | eddymsg_obj should have its payloads split into gpg and non-gpg pieces. | |
557 | ||
558 | Post: | |
559 | Decryption, verification and key imports occur. the gpg_data member of | |
560 | PayloadPiece objects get filled in with GPGData objects. | |
561 | """ | |
38738401 | 562 | |
928e3819 | 563 | if eddymsg_obj.multipart == True: |
101d54a8 | 564 | prev_parts=[] |
928e3819 | 565 | for sub in eddymsg_obj.subparts: |
101d54a8 AE |
566 | gpg_on_payloads (sub, gpgme_ctx, prev_parts) |
567 | prev_parts += [sub] | |
38738401 | 568 | |
d873ff48 | 569 | return |
38738401 | 570 | |
928e3819 | 571 | for piece in eddymsg_obj.payload_pieces: |
38738401 | 572 | |
0fd3389f | 573 | if piece.piece_type == TxtType.text: |
38738401 AE |
574 | # don't transform the plaintext. |
575 | pass | |
576 | ||
0fd3389f | 577 | elif piece.piece_type == TxtType.message: |
7e18f14d | 578 | (plaintext, sigs) = decrypt_block(piece.string, gpgme_ctx) |
38738401 AE |
579 | |
580 | if plaintext: | |
581 | piece.gpg_data = GPGData() | |
b23e171d | 582 | piece.gpg_data.decrypted = True |
38738401 AE |
583 | piece.gpg_data.sigs = sigs |
584 | # recurse! | |
585 | piece.gpg_data.plainobj = parse_pgp_mime(plaintext, gpgme_ctx) | |
3a753fd0 AE |
586 | continue |
587 | ||
588 | # if not encrypted, check to see if this is an armored signature. | |
589 | (plaintext, sigs) = verify_sig_message(piece.string, gpgme_ctx) | |
590 | ||
591 | if plaintext: | |
0fd3389f | 592 | piece.piece_type = TxtType.signature |
3a753fd0 AE |
593 | piece.gpg_data = GPGData() |
594 | piece.gpg_data.sigs = sigs | |
595 | # recurse! | |
596 | piece.gpg_data.plainobj = parse_pgp_mime(plaintext, gpgme_ctx) | |
129543c3 | 597 | |
d7d8bf7c AE |
598 | # FIXME: consider handling pubkeys first, so that signatures can be |
599 | # validated on freshly imported keys | |
0fd3389f | 600 | elif piece.piece_type == TxtType.pubkey: |
f8ee6bd3 | 601 | key_fps = add_gpg_key(piece.string, gpgme_ctx) |
8f61c66a | 602 | |
f8ee6bd3 | 603 | if key_fps != []: |
8f61c66a | 604 | piece.gpg_data = GPGData() |
f8ee6bd3 | 605 | piece.gpg_data.keys = key_fps |
129543c3 | 606 | |
0fd3389f | 607 | elif piece.piece_type == TxtType.detachedsig: |
101d54a8 | 608 | for prev in prev_parts: |
6d8faaa7 | 609 | sig_fps = verify_detached_signature(piece.string, prev.payload_bytes, gpgme_ctx) |
101d54a8 | 610 | |
6d240f68 AE |
611 | if sig_fps != []: |
612 | piece.gpg_data = GPGData() | |
613 | piece.gpg_data.sigs = sig_fps | |
614 | piece.gpg_data.plainobj = prev | |
615 | break | |
7e18f14d | 616 | |
38738401 AE |
617 | else: |
618 | pass | |
619 | ||
620 | ||
928e3819 | 621 | def prepare_for_reply (eddymsg_obj, replyinfo_obj): |
67691346 AE |
622 | """Updates replyinfo_obj with info on the message's GPG success/failures |
623 | ||
624 | This function marks replyinfo_obj with information about whether encrypted | |
625 | text in eddymsg_obj was successfully decrypted, signatures were verified | |
626 | and whether a public key was found or not. | |
627 | ||
628 | Args: | |
629 | eddymsg_obj: a message in the EddyMsg format | |
630 | replyinfo_obj: an instance of ReplyInfo | |
631 | ||
632 | Returns: | |
633 | Nothing | |
634 | ||
635 | Pre: | |
636 | eddymsg_obj has had its gpg_data created by gpg_on_payloads | |
637 | ||
638 | Post: | |
639 | replyinfo_obj has been updated with info about decryption/sig | |
640 | verififcation status, etc. However the desired key isn't imported until | |
641 | later, so the success or failure of that updates the values set here. | |
642 | """ | |
dd11a483 | 643 | |
928e3819 | 644 | do_to_eddys_pieces(prepare_for_reply_pieces, eddymsg_obj, replyinfo_obj) |
56578eaf | 645 | |
928e3819 | 646 | def prepare_for_reply_pieces (eddymsg_obj, replyinfo_obj): |
67691346 AE |
647 | """A helper function for prepare_for_reply |
648 | ||
649 | It updates replyinfo_obj with GPG success/failure information, when | |
650 | supplied a single-part EddyMsg object. | |
651 | ||
652 | Args: | |
653 | eddymsg_obj: a single-part message in the EddyMsg format | |
654 | replyinfo_obj: an object which holds information about the message's | |
655 | GPG status | |
656 | ||
657 | Returns: | |
658 | Nothing | |
659 | ||
660 | Pre: | |
661 | eddymsg_obj is a single-part message. (it may be a part of a multi-part | |
662 | message.) It has had its gpg_data created by gpg_on_payloads if it has | |
663 | gpg data. | |
664 | ||
665 | Post: | |
666 | replyinfo_obj has been updated with gpg success/failure information | |
667 | """ | |
56578eaf | 668 | |
928e3819 | 669 | for piece in eddymsg_obj.payload_pieces: |
0fd3389f | 670 | if piece.piece_type == TxtType.text: |
d873ff48 AE |
671 | # don't quote the plaintext part. |
672 | pass | |
673 | ||
0fd3389f | 674 | elif piece.piece_type == TxtType.message: |
05683768 | 675 | prepare_for_reply_message(piece, replyinfo_obj) |
d873ff48 | 676 | |
0fd3389f | 677 | elif piece.piece_type == TxtType.pubkey: |
05683768 | 678 | prepare_for_reply_pubkey(piece, replyinfo_obj) |
6906d46d | 679 | |
0fd3389f AE |
680 | elif (piece.piece_type == TxtType.detachedsig) \ |
681 | or (piece.piece_type == TxtType.signature): | |
05683768 | 682 | prepare_for_reply_sig(piece, replyinfo_obj) |
d873ff48 | 683 | |
d873ff48 | 684 | |
05683768 | 685 | def prepare_for_reply_message (piece, replyinfo_obj): |
67691346 AE |
686 | """Helper function for prepare_for_reply() |
687 | ||
688 | This function is called when the piece_type of a payload piece is | |
0fd3389f | 689 | TxtType.message, or GPG Message block. This should be encrypted text. If the |
67691346 AE |
690 | encryted block is signed, a sig will be attached to .target_key unless |
691 | there is already one there. | |
692 | ||
693 | Args: | |
694 | piece: a PayloadPiece object. | |
695 | replyinfo_obj: object which gets updated with decryption status, etc. | |
696 | ||
697 | ||
698 | Returns: | |
699 | Nothing | |
700 | ||
701 | Pre: | |
0fd3389f | 702 | the piece.payload_piece value should be TxtType.message. |
67691346 AE |
703 | |
704 | Post: | |
705 | replyinfo_obj gets updated with decryption status, signing status and a | |
706 | potential signing key. | |
707 | """ | |
44fe39b7 | 708 | |
05683768 AE |
709 | if piece.gpg_data == None: |
710 | replyinfo_obj.failed_decrypt = True | |
711 | return | |
712 | ||
5c40e676 | 713 | replyinfo_obj.success_decrypt = True |
05683768 AE |
714 | |
715 | # we already have a key (and a message) | |
716 | if replyinfo_obj.target_key != None: | |
717 | return | |
718 | ||
719 | if piece.gpg_data.sigs != []: | |
720 | replyinfo_obj.target_key = piece.gpg_data.sigs[0] | |
721 | get_signed_part = False | |
722 | else: | |
723 | # only include a signed message in the reply. | |
724 | get_signed_part = True | |
725 | ||
8c3e5397 | 726 | flatten_decrypted_payloads(piece.gpg_data.plainobj, replyinfo_obj, get_signed_part) |
05683768 AE |
727 | |
728 | # to catch public keys in encrypted blocks | |
729 | prepare_for_reply(piece.gpg_data.plainobj, replyinfo_obj) | |
730 | ||
731 | ||
732 | def prepare_for_reply_pubkey (piece, replyinfo_obj): | |
67691346 AE |
733 | """Helper function for prepare_for_reply(). Marks pubkey import status. |
734 | ||
735 | Marks replyinfo_obj with pub key import status. | |
736 | ||
737 | Args: | |
738 | piece: a PayloadPiece object | |
739 | replyinfo_obj: a ReplyInfo object | |
740 | ||
741 | Pre: | |
0fd3389f | 742 | piece.piece_type should be set to TxtType.pubkey . |
67691346 AE |
743 | |
744 | Post: | |
745 | replyinfo_obj has its fields updated. | |
746 | """ | |
05683768 AE |
747 | |
748 | if piece.gpg_data == None or piece.gpg_data.keys == []: | |
749 | replyinfo_obj.no_public_key = True | |
750 | else: | |
751 | replyinfo_obj.public_key_received = True | |
752 | ||
3ceb92e5 AE |
753 | # prefer public key as a fallback for the encrypted reply |
754 | replyinfo_obj.fallback_target_key = piece.gpg_data.keys[0] | |
05683768 AE |
755 | |
756 | ||
757 | def prepare_for_reply_sig (piece, replyinfo_obj): | |
67691346 AE |
758 | """Helper function for prepare_for_reply(). Marks sig verification status. |
759 | ||
760 | Marks replyinfo_obj with signature verification status. | |
761 | ||
762 | Args: | |
763 | piece: a PayloadPiece object | |
764 | replyinfo_obj: a ReplyInfo object | |
765 | ||
766 | Pre: | |
0fd3389f AE |
767 | piece.piece_type should be set to TxtType.signature, or |
768 | TxtType.detachedsig . | |
67691346 AE |
769 | |
770 | Post: | |
771 | replyinfo_obj has its fields updated. | |
772 | """ | |
05683768 AE |
773 | |
774 | if piece.gpg_data == None or piece.gpg_data.sigs == []: | |
775 | replyinfo_obj.sig_failure = True | |
776 | else: | |
777 | replyinfo_obj.sig_success = True | |
778 | ||
779 | if replyinfo_obj.fallback_target_key == None: | |
780 | replyinfo_obj.fallback_target_key = piece.gpg_data.sigs[0] | |
6906d46d AE |
781 | |
782 | ||
8c3e5397 AE |
783 | def flatten_decrypted_payloads (eddymsg_obj, replyinfo_obj, get_signed_part): |
784 | """For creating a string representation of a signed, encrypted part. | |
39e2c525 | 785 | |
8c3e5397 AE |
786 | When given a decrypted payload, it will add either the plaintext or signed |
787 | plaintext to the reply message, depeding on 'get_signed_part'. This is | |
788 | useful for ensuring that the reply message only comes from a signed and | |
789 | ecrypted GPG message. It also sets the target_key for encrypting the reply | |
790 | if it's told to get signed text only. | |
39e2c525 AE |
791 | |
792 | Args: | |
793 | eddymsg_obj: the message in EddyMsg format created by decrypting GPG | |
794 | text | |
8c3e5397 AE |
795 | replyinfo_obj: a ReplyInfo object for holding the message to quote and |
796 | the target_key to encrypt to. | |
39e2c525 AE |
797 | get_signed_part: True if we should only include text that contains a |
798 | further signature. If False, then include plain text. | |
799 | ||
800 | Returns: | |
8c3e5397 | 801 | Nothing |
39e2c525 AE |
802 | |
803 | Pre: | |
804 | The EddyMsg instance passed in should be a piece.gpg_data.plainobj | |
805 | which represents decrypted text. It may or may not be signed on that | |
806 | level. | |
d873ff48 | 807 | |
8c3e5397 AE |
808 | Post: |
809 | the ReplyInfo instance may have a new 'target_key' set and its | |
810 | 'msg_to_quote' will be updated with (possibly signed) plaintext, if any | |
811 | could be found. | |
812 | """ | |
d873ff48 | 813 | |
0aa88c27 | 814 | if eddymsg_obj == None: |
8c3e5397 | 815 | return |
0aa88c27 | 816 | |
0402995a | 817 | # recurse on multi-part mime |
928e3819 AE |
818 | if eddymsg_obj.multipart == True: |
819 | for sub in eddymsg_obj.subparts: | |
8c3e5397 | 820 | flatten_decrypted_payloads(sub, replyinfo_obj, get_signed_part) |
d873ff48 | 821 | |
928e3819 | 822 | for piece in eddymsg_obj.payload_pieces: |
0402995a | 823 | if (get_signed_part): |
0fd3389f AE |
824 | if ((piece.piece_type == TxtType.detachedsig) \ |
825 | or (piece.piece_type == TxtType.signature)) \ | |
0402995a | 826 | and (piece.gpg_data != None): |
8c3e5397 AE |
827 | flatten_decrypted_payloads(piece.gpg_data.plainobj, replyinfo_obj, False) |
828 | replyinfo_obj.target_key = piece.gpg_data.sigs[0] | |
c3d417bf AE |
829 | break |
830 | else: | |
0fd3389f | 831 | if piece.piece_type == TxtType.text: |
8c3e5397 | 832 | replyinfo_obj.msg_to_quote += piece.string |
d873ff48 AE |
833 | |
834 | ||
013f7cb8 | 835 | def get_key_from_fp (replyinfo_obj, gpgme_ctx): |
39e2c525 AE |
836 | """Obtains a public key object from a key fingerprint |
837 | ||
838 | If the .target_key is not set, then we use .fallback_target_key. | |
839 | ||
840 | Args: | |
841 | replyinfo_obj: ReplyInfo instance | |
842 | gpgme_ctx: the gpgme context | |
843 | ||
844 | Return: | |
845 | The key object of the key of either the target_key or the fallback one | |
846 | if .target_key is not set. If the key cannot be loaded, then return | |
847 | None. | |
848 | ||
849 | Pre: | |
850 | Loading a key requires that we have the public key imported. This | |
851 | requires that they email contains the pub key block, or that it was | |
852 | previously sent to edward. | |
853 | ||
854 | Post: | |
855 | If the key cannot be loaded, then the replyinfo_obj is marked for | |
856 | having no public key available. | |
857 | """ | |
013f7cb8 | 858 | |
dc24daf1 AE |
859 | if replyinfo_obj.target_key == None: |
860 | replyinfo_obj.target_key = replyinfo_obj.fallback_target_key | |
861 | ||
013f7cb8 AE |
862 | if replyinfo_obj.target_key != None: |
863 | try: | |
864 | encrypt_to_key = gpgme_ctx.get_key(replyinfo_obj.target_key) | |
865 | return encrypt_to_key | |
866 | ||
5f6f32b1 | 867 | except gpgme.GpgmeError: |
013f7cb8 AE |
868 | pass |
869 | ||
870 | # no available key to use | |
871 | replyinfo_obj.target_key = None | |
872 | replyinfo_obj.fallback_target_key = None | |
873 | ||
874 | replyinfo_obj.no_public_key = True | |
875 | replyinfo_obj.public_key_received = False | |
876 | ||
877 | return None | |
878 | ||
879 | ||
d873ff48 | 880 | def write_reply (replyinfo_obj): |
39e2c525 AE |
881 | """Write the reply email body about the GPG successes/failures. |
882 | ||
883 | The reply is about whether decryption, sig verification and key | |
884 | import/loading was successful or failed. If text was successfully decrypted | |
885 | and verified, then the first instance of such text will be included in | |
886 | quoted form. | |
887 | ||
888 | Args: | |
889 | replyinfo_obj: contains details of GPG processing status | |
890 | ||
891 | Returns: | |
892 | the plaintext message to be sent to the user | |
893 | ||
894 | Pre: | |
895 | replyinfo_obj should be populated with info about GPG processing status. | |
896 | """ | |
d873ff48 AE |
897 | |
898 | reply_plain = "" | |
899 | ||
900 | if replyinfo_obj.success_decrypt == True: | |
d873ff48 | 901 | reply_plain += replyinfo_obj.replies['success_decrypt'] |
2694709a AE |
902 | |
903 | if replyinfo_obj.no_public_key == False: | |
904 | quoted_text = email_quote_text(replyinfo_obj.msg_to_quote) | |
905 | reply_plain += quoted_text | |
d873ff48 AE |
906 | |
907 | elif replyinfo_obj.failed_decrypt == True: | |
908 | reply_plain += replyinfo_obj.replies['failed_decrypt'] | |
909 | ||
910 | ||
911 | if replyinfo_obj.sig_success == True: | |
912 | reply_plain += "\n\n" | |
913 | reply_plain += replyinfo_obj.replies['sig_success'] | |
914 | ||
915 | elif replyinfo_obj.sig_failure == True: | |
916 | reply_plain += "\n\n" | |
917 | reply_plain += replyinfo_obj.replies['sig_failure'] | |
918 | ||
919 | ||
920 | if replyinfo_obj.public_key_received == True: | |
921 | reply_plain += "\n\n" | |
922 | reply_plain += replyinfo_obj.replies['public_key_received'] | |
923 | ||
924 | elif replyinfo_obj.no_public_key == True: | |
925 | reply_plain += "\n\n" | |
926 | reply_plain += replyinfo_obj.replies['no_public_key'] | |
927 | ||
928 | ||
929 | reply_plain += "\n\n" | |
930 | reply_plain += replyinfo_obj.replies['signature'] | |
56578eaf | 931 | |
d873ff48 | 932 | return reply_plain |
56578eaf AE |
933 | |
934 | ||
8f61c66a | 935 | def add_gpg_key (key_block, gpgme_ctx): |
39e2c525 AE |
936 | """Adds a GPG pubkey to the local keystore |
937 | ||
938 | This adds keys received through email into the key store so they can be | |
939 | used later. | |
940 | ||
941 | Args: | |
942 | key_block: the string form of the ascii-armored public key block | |
943 | gpgme_ctx: the gpgme context | |
944 | ||
945 | Returns: | |
946 | the fingerprint(s) of the imported key(s) | |
947 | """ | |
c267c233 | 948 | |
8f61c66a | 949 | fp = io.BytesIO(key_block.encode('ascii')) |
c267c233 | 950 | |
89c08329 AE |
951 | try: |
952 | result = gpgme_ctx.import_(fp) | |
953 | imports = result.imports | |
954 | except gpgme.GpgmeError: | |
955 | imports = [] | |
c267c233 | 956 | |
f8ee6bd3 | 957 | key_fingerprints = [] |
c267c233 | 958 | |
8f61c66a AE |
959 | if imports != []: |
960 | for import_ in imports: | |
961 | fingerprint = import_[0] | |
f8ee6bd3 | 962 | key_fingerprints += [fingerprint] |
c267c233 | 963 | |
e49673aa | 964 | debug("added gpg key: " + fingerprint) |
ec1e779a | 965 | |
f8ee6bd3 | 966 | return key_fingerprints |
ec1e779a AE |
967 | |
968 | ||
3a753fd0 | 969 | def verify_sig_message (msg_block, gpgme_ctx): |
39e2c525 AE |
970 | """Verifies the signature of a signed, ascii-armored block of text. |
971 | ||
972 | It encodes the string into ascii, since binary GPG files are currently | |
973 | unsupported, and alternative, the ascii-armored format is encodable into | |
974 | ascii. | |
975 | ||
976 | Args: | |
977 | msg_block: a GPG Message block in string form. It may be encrypted or | |
978 | not. If it is encrypted, it will return empty results. | |
979 | gpgme_ctx: the gpgme context | |
980 | ||
981 | Returns: | |
982 | A tuple of the plaintext of the signed part and the list of | |
983 | fingerprints of keys signing the data. If verification failed, perhaps | |
984 | because the message was also encrypted, then empty results are | |
985 | returned. | |
986 | """ | |
3a753fd0 AE |
987 | |
988 | block_b = io.BytesIO(msg_block.encode('ascii')) | |
989 | plain_b = io.BytesIO() | |
990 | ||
991 | try: | |
992 | sigs = gpgme_ctx.verify(block_b, None, plain_b) | |
5f6f32b1 | 993 | except gpgme.GpgmeError: |
3a753fd0 AE |
994 | return ("",[]) |
995 | ||
996 | plaintext = plain_b.getvalue().decode('utf-8') | |
997 | ||
998 | fingerprints = [] | |
999 | for sig in sigs: | |
1000 | fingerprints += [sig.fpr] | |
1001 | return (plaintext, fingerprints) | |
1002 | ||
1003 | ||
101d54a8 | 1004 | def verify_detached_signature (detached_sig, plaintext_bytes, gpgme_ctx): |
39e2c525 AE |
1005 | """Verifies the signature of a detached signature. |
1006 | ||
1007 | This requires the signature part and the signed part as separate arguments. | |
1008 | ||
1009 | Args: | |
1010 | detached_sig: the signature part of the detached signature | |
1011 | plaintext_bytes: the byte form of the message being signed. | |
1012 | gpgme_ctx: the gpgme context | |
1013 | ||
1014 | Returns: | |
1015 | A list of signing fingerprints if the signature verification was | |
1016 | sucessful. Otherwise, an empty list is returned. | |
1017 | """ | |
101d54a8 AE |
1018 | |
1019 | detached_sig_fp = io.BytesIO(detached_sig.encode('ascii')) | |
1020 | plaintext_fp = io.BytesIO(plaintext_bytes) | |
101d54a8 | 1021 | |
ff7aeb3d AE |
1022 | try: |
1023 | result = gpgme_ctx.verify(detached_sig_fp, plaintext_fp, None) | |
1024 | except gpgme.GpgmeError: | |
1025 | return [] | |
101d54a8 AE |
1026 | |
1027 | sig_fingerprints = [] | |
1028 | for res_ in result: | |
1029 | sig_fingerprints += [res_.fpr] | |
1030 | ||
1031 | return sig_fingerprints | |
1032 | ||
1033 | ||
5b3053c1 | 1034 | def decrypt_block (msg_block, gpgme_ctx): |
39e2c525 AE |
1035 | """Decrypts a block of GPG text, and verifies any included sigatures. |
1036 | ||
1037 | Some encypted messages have embeded signatures, so those are verified too. | |
1038 | ||
1039 | Args: | |
1040 | msg_block: the encrypted(/signed) text | |
1041 | gpgme_ctx: the gpgme context | |
1042 | ||
1043 | Returns: | |
1044 | A tuple of plaintext and signatures, if the decryption and signature | |
1045 | verification were successful, respectively. | |
1046 | """ | |
0bec96d6 | 1047 | |
5b3053c1 | 1048 | block_b = io.BytesIO(msg_block.encode('ascii')) |
0bec96d6 AE |
1049 | plain_b = io.BytesIO() |
1050 | ||
afc1f64c AE |
1051 | try: |
1052 | sigs = gpgme_ctx.decrypt_verify(block_b, plain_b) | |
5f6f32b1 | 1053 | except gpgme.GpgmeError: |
afc1f64c | 1054 | return ("",[]) |
0bec96d6 | 1055 | |
6aa41372 | 1056 | plaintext = plain_b.getvalue().decode('utf-8') |
cbdf22c1 AE |
1057 | |
1058 | fingerprints = [] | |
1059 | for sig in sigs: | |
1060 | fingerprints += [sig.fpr] | |
1061 | return (plaintext, fingerprints) | |
0bec96d6 AE |
1062 | |
1063 | ||
dd2b62d7 AE |
1064 | def email_to_from_subject (email_text): |
1065 | """Returns the values of the email's To:, From: and Subject: fields | |
fafa21c3 | 1066 | |
dd2b62d7 | 1067 | Returns this information from an email. |
fafa21c3 | 1068 | |
dd2b62d7 AE |
1069 | Args: |
1070 | email_text: the string form of the email | |
fafa21c3 | 1071 | |
dd2b62d7 AE |
1072 | Returns: |
1073 | the email To:, From:, and Subject: fields as strings | |
1074 | """ | |
d65993b8 AE |
1075 | |
1076 | email_struct = email.parser.Parser().parsestr(email_text) | |
1077 | ||
1078 | email_to = email_struct['To'] | |
1079 | email_from = email_struct['From'] | |
1080 | email_subject = email_struct['Subject'] | |
1081 | ||
1082 | return email_to, email_from, email_subject | |
1083 | ||
1084 | ||
adcef2f7 | 1085 | def import_lang(email_to): |
dd2b62d7 AE |
1086 | """Imports appropriate language file for basic i18n support |
1087 | ||
1088 | The language imported depends on the To: address of the email received by | |
1089 | edward. an -en ending implies the English language, whereas a -ja ending | |
1090 | implies Japanese. The list of supported languages is listed in the 'langs' | |
1091 | list at the beginning of the program. | |
1092 | ||
1093 | Args: | |
1094 | email_to: the string containing the email address that the mail was | |
1095 | sent to. | |
1096 | ||
1097 | Returns: | |
1098 | the reference to the imported language module. The only variable in | |
1099 | this file is the 'replies' dictionary. | |
1100 | """ | |
adcef2f7 | 1101 | |
daed5f10 AE |
1102 | lang_module = "lang.en" |
1103 | ||
5250b3b8 AE |
1104 | if email_to != None: |
1105 | for lang in langs: | |
1106 | if "edward-" + lang in email_to: | |
daed5f10 | 1107 | lang_module = "lang." + re.sub('-', '_', lang) |
adcef2f7 | 1108 | |
daed5f10 | 1109 | return importlib.import_module(lang_module) |
adcef2f7 AE |
1110 | |
1111 | ||
cfb03389 | 1112 | def generate_encrypted_mime (plaintext, email_to, email_subject, encrypt_to_key, |
0a064403 | 1113 | gpgme_ctx): |
dd2b62d7 AE |
1114 | """This function creates the mime email reply. It can encrypt the email. |
1115 | ||
1116 | If the encrypt_key is included, then the email is encrypted and signed. | |
1117 | Otherwise it is unencrypted. | |
1118 | ||
1119 | Args: | |
1120 | plaintext: the plaintext body of the message to create. | |
cfb03389 | 1121 | email_to: the email address to reply to |
dd2b62d7 AE |
1122 | email_subject: the subject to use in reply |
1123 | encrypt_to_key: the key object to use for encrypting the email. (or | |
1124 | None) | |
1125 | gpgme_ctx: the gpgme context | |
1126 | ||
1127 | Returns | |
1128 | A string version of the mime message, possibly encrypted and signed. | |
1129 | """ | |
1da9b527 | 1130 | |
2007103e | 1131 | # quoted printable encoding lets most ascii characters look normal |
2a2359a4 | 1132 | # before the mime message is decoded. |
2007103e AE |
1133 | char_set = email.charset.Charset("utf-8") |
1134 | char_set.body_encoding = email.charset.QP | |
8bdfb6d4 | 1135 | |
2007103e AE |
1136 | # MIMEText doesn't allow setting the text encoding |
1137 | # so we use MIMENonMultipart. | |
1138 | plaintext_mime = MIMENonMultipart('text', 'plain') | |
1139 | plaintext_mime.set_payload(plaintext, charset=char_set) | |
216708e9 AE |
1140 | |
1141 | if (encrypt_to_key != None): | |
8bdfb6d4 AE |
1142 | |
1143 | encrypted_text = encrypt_sign_message(plaintext_mime.as_string(), | |
1144 | encrypt_to_key, | |
40c37ab3 | 1145 | gpgme_ctx) |
b33f601b | 1146 | gpg_payload = encrypted_text |
8bdfb6d4 | 1147 | |
b33f601b AE |
1148 | else: |
1149 | signed_text = sign_message(plaintext_mime.as_string(), gpgme_ctx) | |
1150 | gpg_payload = signed_text | |
8bdfb6d4 | 1151 | |
b33f601b AE |
1152 | control_mime = MIMEApplication("Version: 1", |
1153 | _subtype='pgp-encrypted', | |
1154 | _encoder=email.encoders.encode_7or8bit) | |
1155 | control_mime['Content-Description'] = 'PGP/MIME version identification' | |
1156 | control_mime.set_charset('us-ascii') | |
8bdfb6d4 | 1157 | |
b33f601b AE |
1158 | encoded_mime = MIMEApplication(gpg_payload, |
1159 | _subtype='octet-stream; name="encrypted.asc"', | |
1160 | _encoder=email.encoders.encode_7or8bit) | |
1161 | encoded_mime['Content-Description'] = 'OpenPGP encrypted message' | |
1162 | encoded_mime['Content-Disposition'] = 'inline; filename="encrypted.asc"' | |
1163 | encoded_mime.set_charset('us-ascii') | |
1164 | ||
1165 | message_mime = MIMEMultipart(_subtype="encrypted", protocol="application/pgp-encrypted") | |
1166 | message_mime.attach(control_mime) | |
1167 | message_mime.attach(encoded_mime) | |
1168 | message_mime['Content-Disposition'] = 'inline' | |
216708e9 | 1169 | |
2007103e | 1170 | |
cfb03389 | 1171 | message_mime['To'] = email_to |
2007103e AE |
1172 | message_mime['Subject'] = email_subject |
1173 | ||
1174 | reply = message_mime.as_string() | |
1da9b527 AE |
1175 | |
1176 | return reply | |
1177 | ||
1178 | ||
f87041f8 | 1179 | def email_quote_text (text): |
dd2b62d7 AE |
1180 | """Quotes input text by inserting "> "s |
1181 | ||
1182 | This is useful for quoting a text for the reply message. It inserts "> " | |
1183 | strings at the beginning of lines. | |
1184 | ||
1185 | Args: | |
1186 | text: plain text to quote | |
1187 | ||
1188 | Returns: | |
1189 | Quoted text | |
1190 | """ | |
f87041f8 AE |
1191 | |
1192 | quoted_message = re.sub(r'^', r'> ', text, flags=re.MULTILINE) | |
1193 | ||
1194 | return quoted_message | |
1195 | ||
1196 | ||
0a064403 | 1197 | def encrypt_sign_message (plaintext, encrypt_to_key, gpgme_ctx): |
dd2b62d7 AE |
1198 | """Encrypts and signs plaintext |
1199 | ||
1200 | This encrypts and signs a message. | |
1201 | ||
1202 | Args: | |
1203 | plaintext: text to sign and ecrypt | |
1204 | encrypt_to_key: the key object to encrypt to | |
1205 | gpgme_ctx: the gpgme context | |
1206 | ||
1207 | Returns: | |
1208 | An encrypted and signed string of text | |
1209 | """ | |
897cbaf6 | 1210 | |
b33f601b | 1211 | # the plaintext should be mime encoded in an ascii-compatible form |
6aa41372 | 1212 | plaintext_bytes = io.BytesIO(plaintext.encode('ascii')) |
1da9b527 AE |
1213 | encrypted_bytes = io.BytesIO() |
1214 | ||
897cbaf6 | 1215 | gpgme_ctx.encrypt_sign([encrypt_to_key], gpgme.ENCRYPT_ALWAYS_TRUST, |
1da9b527 AE |
1216 | plaintext_bytes, encrypted_bytes) |
1217 | ||
6aa41372 | 1218 | encrypted_txt = encrypted_bytes.getvalue().decode('ascii') |
1da9b527 AE |
1219 | return encrypted_txt |
1220 | ||
1221 | ||
b33f601b AE |
1222 | def sign_message (plaintext, gpgme_ctx): |
1223 | """Signs plaintext | |
1224 | ||
1225 | This signs a message. | |
1226 | ||
1227 | Args: | |
1228 | plaintext: text to sign | |
1229 | gpgme_ctx: the gpgme context | |
1230 | ||
1231 | Returns: | |
1232 | An armored signature as a string of text | |
1233 | """ | |
1234 | ||
1235 | # the plaintext should be mime encoded in an ascii-compatible form | |
1236 | plaintext_bytes = io.BytesIO(plaintext.encode('ascii')) | |
1237 | signed_bytes = io.BytesIO() | |
1238 | ||
1239 | gpgme_ctx.sign(plaintext_bytes, signed_bytes, gpgme.SIG_MODE_NORMAL) | |
1240 | ||
1241 | signed_txt = signed_bytes.getvalue().decode('ascii') | |
1242 | return signed_txt | |
1243 | ||
1244 | ||
0a064403 | 1245 | def error (error_msg): |
dd2b62d7 AE |
1246 | """Write an error message to stdout |
1247 | ||
1248 | The error message includes the program name. | |
1249 | ||
1250 | Args: | |
1251 | error_msg: the message to print | |
1252 | ||
1253 | Returns: | |
1254 | Nothing | |
1255 | ||
1256 | Post: | |
1257 | An error message is printed to stdout | |
1258 | """ | |
0a064403 | 1259 | |
e4fb2ab2 | 1260 | sys.stderr.write(progname + ": " + str(error_msg) + "\n") |
0a064403 AE |
1261 | |
1262 | ||
5e8f9094 | 1263 | def debug (debug_msg): |
dd2b62d7 AE |
1264 | """Writes a debug message to stdout if debug == True |
1265 | ||
1266 | If the debug option is set in edward_config.py, then the passed message | |
1267 | gets printed to stdout. | |
1268 | ||
1269 | Args: | |
1270 | debug_msg: the message to print to stdout | |
1271 | ||
1272 | Returns: | |
1273 | Nothing | |
1274 | ||
1275 | Post: | |
1276 | A debug message is printed to stdout | |
1277 | """ | |
5e8f9094 AE |
1278 | |
1279 | if edward_config.debug == True: | |
0a064403 | 1280 | error(debug_msg) |
5e8f9094 AE |
1281 | |
1282 | ||
20f6e7c5 | 1283 | def handle_args (): |
dd2b62d7 AE |
1284 | """Sets the progname variable and complains about any arguments |
1285 | ||
1286 | If there are any arguments, then edward complains and quits, because input | |
1287 | is read from stdin. | |
1288 | ||
1289 | Args: | |
1290 | None | |
1291 | ||
1292 | Returns: | |
1293 | None | |
1294 | ||
1295 | Post: | |
1296 | Exits with error 1 if there are arguments, otherwise returns to the | |
1297 | calling function, such as main(). | |
1298 | """ | |
20f6e7c5 | 1299 | |
a51cdb72 AE |
1300 | global progname |
1301 | progname = sys.argv[0] | |
1302 | ||
1303 | if len(sys.argv) > 1: | |
1304 | print(progname + ": error, this program doesn't " \ | |
1305 | "need any arguments.", file=sys.stderr) | |
1306 | exit(1) | |
20f6e7c5 | 1307 | |
20f6e7c5 | 1308 | |
a51cdb72 | 1309 | if __name__ == "__main__": |
dd2b62d7 | 1310 | """Executes main if this file is not loaded interactively""" |
20f6e7c5 | 1311 | |
a51cdb72 | 1312 | main() |
0bec96d6 | 1313 |