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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 |
60ccbaf4 | 41 | import subprocess |
0bec96d6 | 42 | |
8bdfb6d4 AE |
43 | import email.parser |
44 | import email.message | |
45 | import email.encoders | |
46 | ||
e5dd6f23 | 47 | from email.mime.text import MIMEText |
8bdfb6d4 AE |
48 | from email.mime.multipart import MIMEMultipart |
49 | from email.mime.application import MIMEApplication | |
50 | from email.mime.nonmultipart import MIMENonMultipart | |
51 | ||
40c37ab3 | 52 | import edward_config |
c96f3837 | 53 | |
01ceaec3 | 54 | langs = ["de", "el", "en", "es", "fr", "it", "ja", "pt-br", "ro", "ru", "tr"] |
adcef2f7 | 55 | |
def9196c AE |
56 | """This list contains the abbreviated names of reply languages available to |
57 | edward.""" | |
58 | ||
0fd3389f AE |
59 | class TxtType (enum.Enum): |
60 | text = 0 | |
61 | message = 1 | |
62 | pubkey = 2 | |
63 | detachedsig = 3 | |
64 | signature = 4 | |
def9196c | 65 | |
0fd3389f | 66 | |
2f4102b9 | 67 | match_pairs = [(TxtType.message, |
56578eaf | 68 | '-----BEGIN PGP MESSAGE-----.*?-----END PGP MESSAGE-----'), |
0fd3389f | 69 | (TxtType.pubkey, |
56578eaf | 70 | '-----BEGIN PGP PUBLIC KEY BLOCK-----.*?-----END PGP PUBLIC KEY BLOCK-----'), |
0fd3389f | 71 | (TxtType.detachedsig, |
38738401 | 72 | '-----BEGIN PGP SIGNATURE-----.*?-----END PGP SIGNATURE-----')] |
56578eaf | 73 | |
def9196c AE |
74 | """This list of tuples matches query names with re.search() queries used |
75 | to find GPG data for edward to process.""" | |
76 | ||
56578eaf AE |
77 | |
78 | class EddyMsg (object): | |
def9196c AE |
79 | """ |
80 | The EddyMsg class represents relevant parts of a mime message. | |
81 | ||
82 | The represented message can be single-part or multi-part. | |
83 | ||
84 | 'multipart' is set to True if there are multiple mime parts. | |
85 | ||
86 | 'subparts' points to a list of mime sub-parts if it is a multi-part | |
87 | message. Otherwise it points to an empty list. | |
88 | ||
6d8faaa7 AE |
89 | 'payload_bytes' is a binary representation of the mime part before header |
90 | removal and message decoding. | |
def9196c AE |
91 | |
92 | 'payload_pieces' is a list of objects containing strings that when strung | |
93 | together form the fully-decoded string representation of the mime part. | |
94 | ||
def9196c AE |
95 | The 'filename', 'content_type' and 'description_list' come from the mime |
96 | part parameters. | |
97 | """ | |
98 | ||
7d0b91d2 AE |
99 | multipart = False |
100 | subparts = [] | |
56578eaf | 101 | |
7d0b91d2 AE |
102 | payload_bytes = None |
103 | payload_pieces = [] | |
56578eaf | 104 | |
7d0b91d2 AE |
105 | filename = None |
106 | content_type = None | |
107 | description_list = None | |
56578eaf AE |
108 | |
109 | ||
110 | class PayloadPiece (object): | |
def9196c AE |
111 | """ |
112 | PayloadPiece represents a complte or sub-section of a mime part. | |
113 | ||
114 | Instances of this class are often strung together within one or more arrays | |
115 | pointed to by each instance of the EddyMsg class. | |
116 | ||
0fd3389f AE |
117 | 'piece_type' refers to an enum whose value describes the content of |
118 | 'string'. Examples include TxtType.pubkey, for public keys, and | |
119 | TxtType.message, for encrypted data (or armored signatures until they are | |
120 | known to be such.) Some of the names derive from the header and footer of | |
121 | each of these ascii-encoded gpg blocks. | |
def9196c AE |
122 | |
123 | 'string' contains some string of text, such as non-GPG text, an encrypted | |
124 | block of text, a signature, or a public key. | |
125 | ||
126 | 'gpg_data' points to any instances of GPGData that have been created based | |
127 | on the contents of 'string'. | |
128 | """ | |
129 | ||
7d0b91d2 AE |
130 | piece_type = None |
131 | string = None | |
132 | gpg_data = None | |
56578eaf AE |
133 | |
134 | ||
38738401 | 135 | class GPGData (object): |
def9196c AE |
136 | """ |
137 | GPGData holds info from decryption, sig. verification, and/or pub. keys. | |
138 | ||
139 | Instances of this class contain decrypted information, signature | |
140 | fingerprints and/or fingerprints of processed and imported public keys. | |
141 | ||
142 | 'decrypted' is set to True if 'plainobj' was created from encrypted data. | |
143 | ||
144 | 'plainobj' points to any decrypted, or signed part of, a GPG signature. It | |
145 | is intended to be an instance of the EddyMsg class. | |
146 | ||
147 | 'sigs' is a list of fingerprints of keys used to sign the data in plainobj. | |
148 | ||
b4c116d5 AE |
149 | 'sigkey_missing' is set to True if edward doesn't have the key it needs to |
150 | verify the signature on a block of text. | |
9af26cb8 | 151 | |
def9196c AE |
152 | 'keys' is a list of fingerprints of keys obtained in public key blocks. |
153 | """ | |
154 | ||
7d0b91d2 AE |
155 | decrypted = False |
156 | ||
157 | plainobj = None | |
158 | sigs = [] | |
b4c116d5 | 159 | sigkey_missing = False |
7d0b91d2 | 160 | keys = [] |
38738401 | 161 | |
38738401 | 162 | |
d873ff48 | 163 | class ReplyInfo (object): |
def9196c AE |
164 | """ |
165 | ReplyInfo contains details that edward uses in generating its reply. | |
166 | ||
167 | Instances of this class contain information about whether a message was | |
168 | successfully encrypted or signed, and whether a public key was attached, or | |
169 | retrievable, from the local GPG store. It stores the fingerprints of | |
170 | potential encryption key candidates and the message (if any at all) to | |
171 | quote in edward's reply. | |
172 | ||
173 | 'replies' points one of the dictionaries of translated replies. | |
174 | ||
175 | 'target_key' refers to the fingerprint of a key used to sign encrypted | |
176 | data. This is the preferred key, if it is set, and if is available. | |
177 | ||
178 | 'fallback_target_key' referst to the fingerprint of a key used to sign | |
179 | unencrypted data; alternatively it may be a public key attached to the | |
180 | message. | |
181 | ||
ca37d0cb AE |
182 | 'encrypt_to_key' the key object to use when encrypting edward's reply |
183 | ||
def9196c AE |
184 | 'msg_to_quote' refers to the part of a message which edward should quote in |
185 | his reply. This should remain as None if there was no encrypted and singed | |
186 | part. This is to avoid making edward a service for decrypting other | |
187 | people's messages to edward. | |
188 | ||
b4c116d5 | 189 | 'decrypt_success' is set to True if edward could decrypt part of the |
def9196c AE |
190 | message. |
191 | ||
def9196c AE |
192 | 'sig_success' is set to True if edward could to some extent verify the |
193 | signature of a signed part of the message to edward. | |
194 | ||
32a8996f AE |
195 | 'sig_failure' is set to True if edward could not verify a siganture. |
196 | ||
b4c116d5 AE |
197 | 'pubkey_success' is set to True if edward successfully imported a public |
198 | key. | |
199 | ||
200 | 'sigkey_missing' is set to True if edward doesn't have the public key | |
201 | needed for signature verification. | |
202 | ||
203 | 'have_repy_key' is set to True if edward has a public key to encrypt its | |
204 | reply to. | |
def9196c AE |
205 | """ |
206 | ||
7d0b91d2 | 207 | replies = None |
6906d46d | 208 | |
7d0b91d2 AE |
209 | target_key = None |
210 | fallback_target_key = None | |
ca37d0cb | 211 | encrypt_to_key = None |
7d0b91d2 | 212 | msg_to_quote = "" |
d873ff48 | 213 | |
b4c116d5 | 214 | decrypt_success = False |
7d0b91d2 | 215 | sig_success = False |
b4c116d5 AE |
216 | pubkey_success = False |
217 | ||
4e2c66f7 | 218 | decrypt_failure = False |
32a8996f | 219 | sig_failure = False |
b4c116d5 AE |
220 | sigkey_missing = False |
221 | have_reply_key = False | |
d873ff48 | 222 | |
38738401 | 223 | |
0bec96d6 AE |
224 | def main (): |
225 | ||
def9196c AE |
226 | """ |
227 | This is the main function for edward, a GPG reply bot. | |
228 | ||
229 | Edward responds to GPG-encrypted and signed mail, encrypting and signing | |
230 | the response if the user's public key is, or was, included in the message. | |
231 | ||
232 | Args: | |
233 | None | |
234 | ||
235 | Returns: | |
a3d6aff8 | 236 | Nothing |
def9196c AE |
237 | |
238 | Pre: | |
239 | Mime or plaintext email passing in through standard input. Portions of | |
240 | the email may be encrypted. If the To: address contains the text | |
241 | "edward-ja", then the reply will contain a reply written in the | |
242 | Japanese language. There are other languages as well. The default | |
243 | language is English. | |
244 | ||
245 | Post: | |
246 | A reply email will be printed to standard output. The contents of the | |
247 | reply email depends on whether the original email was encrypted or not, | |
248 | has or doesn't have a signature, whether a public key used in the | |
249 | original message is provided or locally stored, and the language | |
250 | implied by the To: address in the original email. | |
251 | """ | |
252 | ||
60ccbaf4 | 253 | print_reply_only = handle_args() |
0bec96d6 | 254 | |
0a064403 AE |
255 | gpgme_ctx = get_gpg_context(edward_config.gnupghome, |
256 | edward_config.sign_with_key) | |
257 | ||
85a829fc AE |
258 | email_bytes = sys.stdin.buffer.read() |
259 | email_struct = parse_pgp_mime(email_bytes, gpgme_ctx) | |
adcef2f7 | 260 | |
85a829fc | 261 | email_to, email_from, email_subject = email_to_from_subject(email_bytes) |
60ccbaf4 | 262 | lang, reply_from = import_lang_pick_address(email_to, edward_config.hostname) |
fafa21c3 | 263 | |
d873ff48 AE |
264 | replyinfo_obj = ReplyInfo() |
265 | replyinfo_obj.replies = lang.replies | |
266 | ||
267 | prepare_for_reply(email_struct, replyinfo_obj) | |
ca37d0cb | 268 | get_key_from_fp(replyinfo_obj, gpgme_ctx) |
d873ff48 | 269 | reply_plaintext = write_reply(replyinfo_obj) |
adcef2f7 | 270 | |
2007103e | 271 | reply_mime = generate_encrypted_mime(reply_plaintext, email_from, \ |
ca37d0cb | 272 | email_subject, replyinfo_obj.encrypt_to_key, |
2007103e | 273 | gpgme_ctx) |
1fccb295 | 274 | |
60ccbaf4 AE |
275 | if print_reply_only == True: |
276 | print(reply_mime) | |
277 | else: | |
278 | send_reply(reply_mime, email_subject, email_from, reply_from) | |
c96f3837 | 279 | |
0bec96d6 | 280 | |
0a064403 | 281 | def get_gpg_context (gnupghome, sign_with_key_fp): |
a3d6aff8 AE |
282 | """ |
283 | This function returns the GPG context needed for encryption and signing. | |
284 | ||
285 | The context is needed by other functions which use GPG functionality. | |
286 | ||
287 | Args: | |
288 | gnupghome: The path to "~/.gnupg/" or its alternative. | |
289 | sign_with_key: The fingerprint of the key to sign with | |
290 | ||
291 | Returns: | |
292 | A gpgme context to be used for GPG functions. | |
293 | ||
294 | Post: | |
295 | the 'armor' flag is set to True and the list of signing keys contains | |
296 | the single specified key | |
297 | """ | |
0a064403 AE |
298 | |
299 | os.environ['GNUPGHOME'] = gnupghome | |
300 | ||
301 | gpgme_ctx = gpgme.Context() | |
302 | gpgme_ctx.armor = True | |
303 | ||
304 | try: | |
305 | sign_with_key = gpgme_ctx.get_key(sign_with_key_fp) | |
5f6f32b1 | 306 | except gpgme.GpgmeError: |
0a064403 AE |
307 | error("unable to load signing key. is the gnupghome " |
308 | + "and signing key properly set in the edward_config.py?") | |
309 | exit(1) | |
310 | ||
311 | gpgme_ctx.signers = [sign_with_key] | |
312 | ||
313 | return gpgme_ctx | |
314 | ||
315 | ||
85a829fc | 316 | def parse_pgp_mime (email_bytes, gpgme_ctx): |
a3d6aff8 AE |
317 | """Parses the email for mime payloads and decrypts/verfies signatures. |
318 | ||
319 | This function creates a representation of a mime or plaintext email with | |
320 | the EddyMsg class. It then splits each mime payload into one or more pieces | |
321 | which may be plain text or GPG data. It then decrypts encrypted parts and | |
322 | does some very basic signature verification on those parts. | |
323 | ||
324 | Args: | |
85a829fc | 325 | email_bytes: an email message in byte string format |
a3d6aff8 AE |
326 | gpgme_ctx: a gpgme context |
327 | ||
328 | Returns: | |
329 | A message as an instance of EddyMsg | |
330 | ||
331 | Post: | |
332 | the returned EddyMsg instance has split, decrypted, verified and pubkey | |
333 | imported payloads | |
334 | """ | |
394a1476 | 335 | |
85a829fc | 336 | email_struct = email.parser.BytesParser().parsebytes(email_bytes) |
394a1476 | 337 | |
928e3819 AE |
338 | eddymsg_obj = parse_mime(email_struct) |
339 | split_payloads(eddymsg_obj) | |
340 | gpg_on_payloads(eddymsg_obj, gpgme_ctx) | |
8bb4b0d5 | 341 | |
928e3819 | 342 | return eddymsg_obj |
0bec96d6 | 343 | |
0bec96d6 | 344 | |
56578eaf | 345 | def parse_mime(msg_struct): |
a3d6aff8 AE |
346 | """Translates python's email.parser format into an EddyMsg format |
347 | ||
348 | If the message is multi-part, then a recursive object is created, where | |
349 | each sub-part is also a EddyMsg instance. | |
350 | ||
351 | Args: | |
352 | msg_struct: an email parsed with email.parser.Parser(), which can be | |
353 | multi-part | |
354 | ||
355 | Returns: | |
356 | an instance of EddyMsg, potentially a recursive one. | |
357 | """ | |
0bec96d6 | 358 | |
928e3819 | 359 | eddymsg_obj = EddyMsg() |
8bb4b0d5 | 360 | |
56578eaf AE |
361 | if msg_struct.is_multipart() == True: |
362 | payloads = msg_struct.get_payload() | |
0bec96d6 | 363 | |
928e3819 AE |
364 | eddymsg_obj.multipart = True |
365 | eddymsg_obj.subparts = list(map(parse_mime, payloads)) | |
dd11a483 | 366 | |
56578eaf | 367 | else: |
928e3819 | 368 | eddymsg_obj = get_subpart_data(msg_struct) |
394a1476 | 369 | |
928e3819 | 370 | return eddymsg_obj |
c267c233 | 371 | |
80119cab | 372 | |
2f4102b9 | 373 | def scan_and_split (payload_piece, match_name, pattern): |
a3d6aff8 AE |
374 | """This splits the payloads of an EddyMsg object into GPG and text parts. |
375 | ||
376 | An EddyMsg object's payload_pieces starts off as a list containing a single | |
377 | PayloadPiece object. This function returns a list of these objects which | |
378 | have been split into GPG data and regular text, if such splits need to be/ | |
379 | can be made. | |
380 | ||
381 | Args: | |
382 | payload_piece: a single payload or a split part of a payload | |
2f4102b9 | 383 | match_name: the type of data to try to spit out from the payload piece |
a3d6aff8 AE |
384 | pattern: the search pattern to be used for finding that type of data |
385 | ||
386 | Returns: | |
387 | a list of objects of the PayloadPiece class, in the order that the | |
388 | string part of payload_piece originally was, broken up according to | |
389 | matches specified by 'pattern'. | |
390 | """ | |
cf75de65 | 391 | |
a5d37d44 | 392 | # don't try to re-split pieces containing gpg data |
0fd3389f | 393 | if payload_piece.piece_type != TxtType.text: |
a5d37d44 AE |
394 | return [payload_piece] |
395 | ||
56578eaf AE |
396 | flags = re.DOTALL | re.MULTILINE |
397 | matches = re.search("(?P<beginning>.*?)(?P<match>" + pattern + | |
398 | ")(?P<rest>.*)", payload_piece.string, flags=flags) | |
86663388 | 399 | |
56578eaf AE |
400 | if matches == None: |
401 | pieces = [payload_piece] | |
c96f3837 | 402 | |
56578eaf | 403 | else: |
d437f8b2 | 404 | |
56578eaf AE |
405 | beginning = PayloadPiece() |
406 | beginning.string = matches.group('beginning') | |
407 | beginning.piece_type = payload_piece.piece_type | |
d437f8b2 | 408 | |
56578eaf AE |
409 | match = PayloadPiece() |
410 | match.string = matches.group('match') | |
2f4102b9 | 411 | match.piece_type = match_name |
d437f8b2 | 412 | |
56578eaf AE |
413 | rest = PayloadPiece() |
414 | rest.string = matches.group('rest') | |
415 | rest.piece_type = payload_piece.piece_type | |
d437f8b2 | 416 | |
2f4102b9 | 417 | more_pieces = scan_and_split(rest, match_name, pattern) |
4615b156 | 418 | pieces = [beginning, match ] + more_pieces |
d437f8b2 | 419 | |
56578eaf | 420 | return pieces |
d437f8b2 | 421 | |
d437f8b2 | 422 | |
56578eaf | 423 | def get_subpart_data (part): |
a3d6aff8 AE |
424 | """This function grabs information from a single part mime object. |
425 | ||
426 | It copies needed data from a single part email.parser.Parser() object over | |
427 | to an EddyMsg object. | |
428 | ||
429 | Args: | |
430 | part: a non-multi-part mime.parser.Parser() object | |
431 | ||
432 | Returns: | |
433 | a single-part EddyMsg() object | |
434 | """ | |
0bec96d6 | 435 | |
6d8faaa7 | 436 | obj = EddyMsg() |
56578eaf | 437 | |
84ff9773 AE |
438 | mime_decoded_bytes = part.get_payload(decode=True) |
439 | charset = part.get_content_charset() | |
56578eaf AE |
440 | |
441 | # your guess is as good as a-myy-ee-ine... | |
6d8faaa7 AE |
442 | if charset == None: |
443 | charset = 'utf-8' | |
56578eaf | 444 | |
84ff9773 AE |
445 | payload_string = part.as_string() |
446 | if payload_string != None: | |
447 | obj.payload_bytes = payload_string.encode(charset) | |
448 | ||
449 | obj.filename = part.get_filename() | |
450 | obj.content_type = part.get_content_type() | |
451 | obj.description_list = part['content-description'] | |
452 | ||
6d8faaa7 | 453 | if mime_decoded_bytes != None: |
0eb75d9c AE |
454 | try: |
455 | payload = PayloadPiece() | |
6d8faaa7 | 456 | payload.string = mime_decoded_bytes.decode(charset) |
0fd3389f | 457 | payload.piece_type = TxtType.text |
0eb75d9c AE |
458 | |
459 | obj.payload_pieces = [payload] | |
460 | except UnicodeDecodeError: | |
461 | pass | |
56578eaf AE |
462 | |
463 | return obj | |
464 | ||
465 | ||
928e3819 | 466 | def do_to_eddys_pieces (function_to_do, eddymsg_obj, data): |
a3d6aff8 AE |
467 | """A function which maps another function onto a message's subparts. |
468 | ||
469 | This is a higer-order function which recursively performs a specified | |
470 | function on each subpart of a multi-part message. Each single-part sub-part | |
471 | has the function applied to it. This function also works if the part passed | |
472 | in is single-part. | |
473 | ||
474 | Args: | |
475 | function_to_do: function to perform on sub-parts | |
476 | eddymsg_obj: a single part or multi-part EddyMsg object | |
477 | data: a second argument to pass to 'function_to_do' | |
478 | ||
479 | Returns: | |
480 | Nothing | |
481 | ||
482 | Post: | |
483 | The passed-in EddyMsg object is transformed recursively on its | |
484 | sub-parts according to 'function_to_do'. | |
485 | """ | |
56578eaf | 486 | |
928e3819 AE |
487 | if eddymsg_obj.multipart == True: |
488 | for sub in eddymsg_obj.subparts: | |
d873ff48 | 489 | do_to_eddys_pieces(function_to_do, sub, data) |
394a1476 | 490 | else: |
928e3819 | 491 | function_to_do(eddymsg_obj, data) |
dd11a483 AE |
492 | |
493 | ||
928e3819 | 494 | def split_payloads (eddymsg_obj): |
a3d6aff8 AE |
495 | """Splits all (sub-)payloads of a message into GPG data and regular text. |
496 | ||
497 | Recursively performs payload splitting on all sub-parts of an EddyMsg | |
498 | object into the various GPG data types, such as GPG messages, public key | |
499 | blocks and signed text. | |
500 | ||
501 | Args: | |
502 | eddymsg_obj: an instance of EddyMsg | |
503 | ||
504 | Returns: | |
505 | Nothing | |
506 | ||
507 | Pre: | |
508 | The EddyMsg object has payloads that are unsplit (by may be split).. | |
509 | ||
510 | Post: | |
511 | The EddyMsg object's payloads are all split into GPG and non-GPG parts. | |
512 | """ | |
a5d37d44 | 513 | |
2f4102b9 AE |
514 | for match_pair in match_pairs: |
515 | do_to_eddys_pieces(split_payload_pieces, eddymsg_obj, match_pair) | |
a5d37d44 | 516 | |
a5d37d44 | 517 | |
2f4102b9 | 518 | def split_payload_pieces (eddymsg_obj, match_pair): |
a3d6aff8 AE |
519 | """A helper function for split_payloads(); works on PayloadPiece objects. |
520 | ||
521 | This function splits up PayloadPiece objects into multipe PayloadPiece | |
522 | objects and replaces the EddyMsg object's previous list of payload pieces | |
523 | with the new split up one. | |
524 | ||
525 | Args: | |
526 | eddymsg_obj: a single-part EddyMsg object. | |
2f4102b9 | 527 | match_pair: a tuple from the match_pairs list, which specifies a match |
a3d6aff8 AE |
528 | name and a match pattern. |
529 | ||
530 | Returns: | |
531 | Nothing | |
532 | ||
533 | Pre: | |
534 | The payload piece(s) of an EddyMsg object may be already split or | |
535 | unsplit. | |
536 | ||
537 | Post: | |
538 | The EddyMsg object's payload piece(s) are split into a list of pieces | |
2f4102b9 | 539 | if matches of the match_pair are found. |
a3d6aff8 | 540 | """ |
a5d37d44 | 541 | |
2f4102b9 | 542 | (match_name, pattern) = match_pair |
a5d37d44 AE |
543 | |
544 | new_pieces_list = [] | |
928e3819 | 545 | for piece in eddymsg_obj.payload_pieces: |
a5d37d44 AE |
546 | new_pieces_list += scan_and_split(piece, match_name, pattern) |
547 | ||
928e3819 | 548 | eddymsg_obj.payload_pieces = new_pieces_list |
a5d37d44 AE |
549 | |
550 | ||
928e3819 | 551 | def gpg_on_payloads (eddymsg_obj, gpgme_ctx, prev_parts=[]): |
a3d6aff8 AE |
552 | """Performs GPG operations on the GPG parts of the message |
553 | ||
554 | This function decrypts text, verifies signatures, and imports public keys | |
555 | included in an email. | |
556 | ||
557 | Args: | |
558 | eddymsg_obj: an EddyMsg object with its payload_pieces split into GPG | |
559 | and non-GPG sections by split_payloads() | |
560 | gpgme_ctx: a gpgme context | |
561 | ||
562 | prev_parts: a list of mime parts that occur before the eddymsg_obj | |
563 | part, under the same multi-part mime part. This is used for | |
564 | verifying detached signatures. For the root mime part, this should | |
565 | be an empty list, which is the default value if this paramater is | |
566 | omitted. | |
567 | ||
568 | Return: | |
569 | Nothing | |
570 | ||
571 | Pre: | |
572 | eddymsg_obj should have its payloads split into gpg and non-gpg pieces. | |
573 | ||
574 | Post: | |
575 | Decryption, verification and key imports occur. the gpg_data member of | |
576 | PayloadPiece objects get filled in with GPGData objects. | |
577 | """ | |
38738401 | 578 | |
928e3819 | 579 | if eddymsg_obj.multipart == True: |
101d54a8 | 580 | prev_parts=[] |
928e3819 | 581 | for sub in eddymsg_obj.subparts: |
101d54a8 AE |
582 | gpg_on_payloads (sub, gpgme_ctx, prev_parts) |
583 | prev_parts += [sub] | |
38738401 | 584 | |
d873ff48 | 585 | return |
38738401 | 586 | |
928e3819 | 587 | for piece in eddymsg_obj.payload_pieces: |
38738401 | 588 | |
0fd3389f | 589 | if piece.piece_type == TxtType.text: |
38738401 AE |
590 | # don't transform the plaintext. |
591 | pass | |
592 | ||
0fd3389f | 593 | elif piece.piece_type == TxtType.message: |
b4c116d5 AE |
594 | piece.gpg_data = GPGData() |
595 | ||
85a829fc | 596 | (plaintext_b, sigs, sigkey_missing) = decrypt_block(piece.string, gpgme_ctx) |
b4c116d5 AE |
597 | |
598 | piece.gpg_data.sigkey_missing = sigkey_missing | |
38738401 | 599 | |
85a829fc | 600 | if plaintext_b: |
b23e171d | 601 | piece.gpg_data.decrypted = True |
38738401 AE |
602 | piece.gpg_data.sigs = sigs |
603 | # recurse! | |
85a829fc | 604 | piece.gpg_data.plainobj = parse_pgp_mime(plaintext_b, gpgme_ctx) |
3a753fd0 AE |
605 | continue |
606 | ||
607 | # if not encrypted, check to see if this is an armored signature. | |
85a829fc | 608 | (plaintext_b, sigs, sigkey_missing) = verify_sig_message(piece.string, gpgme_ctx) |
b4c116d5 AE |
609 | |
610 | piece.gpg_data.sigkey_missing = sigkey_missing | |
3a753fd0 | 611 | |
85a829fc | 612 | if plaintext_b: |
0fd3389f | 613 | piece.piece_type = TxtType.signature |
3a753fd0 AE |
614 | piece.gpg_data.sigs = sigs |
615 | # recurse! | |
85a829fc | 616 | piece.gpg_data.plainobj = parse_pgp_mime(plaintext_b, gpgme_ctx) |
129543c3 | 617 | |
0fd3389f | 618 | elif piece.piece_type == TxtType.pubkey: |
f8ee6bd3 | 619 | key_fps = add_gpg_key(piece.string, gpgme_ctx) |
8f61c66a | 620 | |
f8ee6bd3 | 621 | if key_fps != []: |
8f61c66a | 622 | piece.gpg_data = GPGData() |
f8ee6bd3 | 623 | piece.gpg_data.keys = key_fps |
129543c3 | 624 | |
0fd3389f | 625 | elif piece.piece_type == TxtType.detachedsig: |
b4c116d5 AE |
626 | piece.gpg_data = GPGData() |
627 | ||
101d54a8 | 628 | for prev in prev_parts: |
b4c116d5 AE |
629 | (sig_fps, sigkey_missing) = verify_detached_signature(piece.string, prev.payload_bytes, gpgme_ctx) |
630 | ||
631 | piece.gpg_data.sigkey_missing = sigkey_missing | |
101d54a8 | 632 | |
6d240f68 | 633 | if sig_fps != []: |
6d240f68 AE |
634 | piece.gpg_data.sigs = sig_fps |
635 | piece.gpg_data.plainobj = prev | |
636 | break | |
7e18f14d | 637 | |
38738401 AE |
638 | else: |
639 | pass | |
640 | ||
641 | ||
928e3819 | 642 | def prepare_for_reply (eddymsg_obj, replyinfo_obj): |
67691346 AE |
643 | """Updates replyinfo_obj with info on the message's GPG success/failures |
644 | ||
645 | This function marks replyinfo_obj with information about whether encrypted | |
646 | text in eddymsg_obj was successfully decrypted, signatures were verified | |
647 | and whether a public key was found or not. | |
648 | ||
649 | Args: | |
650 | eddymsg_obj: a message in the EddyMsg format | |
651 | replyinfo_obj: an instance of ReplyInfo | |
652 | ||
653 | Returns: | |
654 | Nothing | |
655 | ||
656 | Pre: | |
657 | eddymsg_obj has had its gpg_data created by gpg_on_payloads | |
658 | ||
659 | Post: | |
660 | replyinfo_obj has been updated with info about decryption/sig | |
661 | verififcation status, etc. However the desired key isn't imported until | |
662 | later, so the success or failure of that updates the values set here. | |
663 | """ | |
dd11a483 | 664 | |
928e3819 | 665 | do_to_eddys_pieces(prepare_for_reply_pieces, eddymsg_obj, replyinfo_obj) |
56578eaf | 666 | |
928e3819 | 667 | def prepare_for_reply_pieces (eddymsg_obj, replyinfo_obj): |
67691346 AE |
668 | """A helper function for prepare_for_reply |
669 | ||
670 | It updates replyinfo_obj with GPG success/failure information, when | |
671 | supplied a single-part EddyMsg object. | |
672 | ||
673 | Args: | |
674 | eddymsg_obj: a single-part message in the EddyMsg format | |
675 | replyinfo_obj: an object which holds information about the message's | |
676 | GPG status | |
677 | ||
678 | Returns: | |
679 | Nothing | |
680 | ||
681 | Pre: | |
682 | eddymsg_obj is a single-part message. (it may be a part of a multi-part | |
683 | message.) It has had its gpg_data created by gpg_on_payloads if it has | |
684 | gpg data. | |
685 | ||
686 | Post: | |
687 | replyinfo_obj has been updated with gpg success/failure information | |
688 | """ | |
56578eaf | 689 | |
928e3819 | 690 | for piece in eddymsg_obj.payload_pieces: |
0fd3389f | 691 | if piece.piece_type == TxtType.text: |
d873ff48 AE |
692 | # don't quote the plaintext part. |
693 | pass | |
694 | ||
0fd3389f | 695 | elif piece.piece_type == TxtType.message: |
05683768 | 696 | prepare_for_reply_message(piece, replyinfo_obj) |
d873ff48 | 697 | |
0fd3389f | 698 | elif piece.piece_type == TxtType.pubkey: |
05683768 | 699 | prepare_for_reply_pubkey(piece, replyinfo_obj) |
6906d46d | 700 | |
0fd3389f AE |
701 | elif (piece.piece_type == TxtType.detachedsig) \ |
702 | or (piece.piece_type == TxtType.signature): | |
05683768 | 703 | prepare_for_reply_sig(piece, replyinfo_obj) |
d873ff48 | 704 | |
d873ff48 | 705 | |
05683768 | 706 | def prepare_for_reply_message (piece, replyinfo_obj): |
67691346 AE |
707 | """Helper function for prepare_for_reply() |
708 | ||
709 | This function is called when the piece_type of a payload piece is | |
9af26cb8 AE |
710 | TxtType.message, or GPG Message block. This should be encrypted text. If |
711 | the encryted block is correclty signed, a sig will be attached to | |
712 | .target_key unless there is already one there. | |
67691346 AE |
713 | |
714 | Args: | |
715 | piece: a PayloadPiece object. | |
716 | replyinfo_obj: object which gets updated with decryption status, etc. | |
717 | ||
67691346 AE |
718 | Returns: |
719 | Nothing | |
720 | ||
721 | Pre: | |
0fd3389f | 722 | the piece.payload_piece value should be TxtType.message. |
67691346 AE |
723 | |
724 | Post: | |
b4c116d5 AE |
725 | replyinfo_obj gets updated with decryption status, signing status, a |
726 | potential signing key, and posession status of the public key for the | |
727 | signature. | |
67691346 | 728 | """ |
44fe39b7 | 729 | |
b4c116d5 | 730 | if piece.gpg_data == None or piece.gpg_data.plainobj == None: |
4e2c66f7 | 731 | replyinfo_obj.decrypt_failure = True |
05683768 AE |
732 | return |
733 | ||
b4c116d5 | 734 | replyinfo_obj.decrypt_success = True |
05683768 AE |
735 | |
736 | # we already have a key (and a message) | |
737 | if replyinfo_obj.target_key != None: | |
738 | return | |
739 | ||
740 | if piece.gpg_data.sigs != []: | |
741 | replyinfo_obj.target_key = piece.gpg_data.sigs[0] | |
59003069 | 742 | replyinfo_obj.sig_success = True |
05683768 | 743 | get_signed_part = False |
b4c116d5 | 744 | |
05683768 | 745 | else: |
b4c116d5 AE |
746 | if piece.gpg_data.sigkey_missing == True: |
747 | replyinfo_obj.sigkey_missing = True | |
9af26cb8 | 748 | |
05683768 AE |
749 | # only include a signed message in the reply. |
750 | get_signed_part = True | |
751 | ||
8c3e5397 | 752 | flatten_decrypted_payloads(piece.gpg_data.plainobj, replyinfo_obj, get_signed_part) |
05683768 AE |
753 | |
754 | # to catch public keys in encrypted blocks | |
755 | prepare_for_reply(piece.gpg_data.plainobj, replyinfo_obj) | |
756 | ||
757 | ||
758 | def prepare_for_reply_pubkey (piece, replyinfo_obj): | |
67691346 AE |
759 | """Helper function for prepare_for_reply(). Marks pubkey import status. |
760 | ||
761 | Marks replyinfo_obj with pub key import status. | |
762 | ||
763 | Args: | |
764 | piece: a PayloadPiece object | |
765 | replyinfo_obj: a ReplyInfo object | |
766 | ||
767 | Pre: | |
0fd3389f | 768 | piece.piece_type should be set to TxtType.pubkey . |
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.keys == []: | |
b4c116d5 | 775 | pass |
05683768 | 776 | else: |
b4c116d5 | 777 | replyinfo_obj.pubkey_success = True |
05683768 | 778 | |
3ceb92e5 AE |
779 | # prefer public key as a fallback for the encrypted reply |
780 | replyinfo_obj.fallback_target_key = piece.gpg_data.keys[0] | |
05683768 AE |
781 | |
782 | ||
783 | def prepare_for_reply_sig (piece, replyinfo_obj): | |
67691346 AE |
784 | """Helper function for prepare_for_reply(). Marks sig verification status. |
785 | ||
786 | Marks replyinfo_obj with signature verification status. | |
787 | ||
788 | Args: | |
789 | piece: a PayloadPiece object | |
790 | replyinfo_obj: a ReplyInfo object | |
791 | ||
792 | Pre: | |
0fd3389f AE |
793 | piece.piece_type should be set to TxtType.signature, or |
794 | TxtType.detachedsig . | |
67691346 AE |
795 | |
796 | Post: | |
797 | replyinfo_obj has its fields updated. | |
798 | """ | |
05683768 AE |
799 | |
800 | if piece.gpg_data == None or piece.gpg_data.sigs == []: | |
32a8996f | 801 | replyinfo_obj.sig_failure = True |
b4c116d5 AE |
802 | |
803 | if piece.gpg_data.sigkey_missing == True: | |
804 | replyinfo_obj.sigkey_missing = True | |
805 | ||
05683768 AE |
806 | else: |
807 | replyinfo_obj.sig_success = True | |
808 | ||
809 | if replyinfo_obj.fallback_target_key == None: | |
810 | replyinfo_obj.fallback_target_key = piece.gpg_data.sigs[0] | |
6906d46d AE |
811 | |
812 | ||
8c3e5397 AE |
813 | def flatten_decrypted_payloads (eddymsg_obj, replyinfo_obj, get_signed_part): |
814 | """For creating a string representation of a signed, encrypted part. | |
39e2c525 | 815 | |
8c3e5397 AE |
816 | When given a decrypted payload, it will add either the plaintext or signed |
817 | plaintext to the reply message, depeding on 'get_signed_part'. This is | |
818 | useful for ensuring that the reply message only comes from a signed and | |
819 | ecrypted GPG message. It also sets the target_key for encrypting the reply | |
820 | if it's told to get signed text only. | |
39e2c525 AE |
821 | |
822 | Args: | |
823 | eddymsg_obj: the message in EddyMsg format created by decrypting GPG | |
824 | text | |
8c3e5397 AE |
825 | replyinfo_obj: a ReplyInfo object for holding the message to quote and |
826 | the target_key to encrypt to. | |
39e2c525 AE |
827 | get_signed_part: True if we should only include text that contains a |
828 | further signature. If False, then include plain text. | |
829 | ||
830 | Returns: | |
8c3e5397 | 831 | Nothing |
39e2c525 AE |
832 | |
833 | Pre: | |
834 | The EddyMsg instance passed in should be a piece.gpg_data.plainobj | |
835 | which represents decrypted text. It may or may not be signed on that | |
836 | level. | |
d873ff48 | 837 | |
8c3e5397 AE |
838 | Post: |
839 | the ReplyInfo instance may have a new 'target_key' set and its | |
840 | 'msg_to_quote' will be updated with (possibly signed) plaintext, if any | |
841 | could be found. | |
842 | """ | |
d873ff48 | 843 | |
0aa88c27 | 844 | if eddymsg_obj == None: |
8c3e5397 | 845 | return |
0aa88c27 | 846 | |
0402995a | 847 | # recurse on multi-part mime |
928e3819 AE |
848 | if eddymsg_obj.multipart == True: |
849 | for sub in eddymsg_obj.subparts: | |
8c3e5397 | 850 | flatten_decrypted_payloads(sub, replyinfo_obj, get_signed_part) |
d873ff48 | 851 | |
928e3819 | 852 | for piece in eddymsg_obj.payload_pieces: |
0402995a | 853 | if (get_signed_part): |
0fd3389f AE |
854 | if ((piece.piece_type == TxtType.detachedsig) \ |
855 | or (piece.piece_type == TxtType.signature)) \ | |
b4c116d5 AE |
856 | and (piece.gpg_data != None) \ |
857 | and (piece.gpg_data.plainobj != None): | |
8c3e5397 AE |
858 | flatten_decrypted_payloads(piece.gpg_data.plainobj, replyinfo_obj, False) |
859 | replyinfo_obj.target_key = piece.gpg_data.sigs[0] | |
c3d417bf AE |
860 | break |
861 | else: | |
0fd3389f | 862 | if piece.piece_type == TxtType.text: |
8c3e5397 | 863 | replyinfo_obj.msg_to_quote += piece.string |
d873ff48 AE |
864 | |
865 | ||
013f7cb8 | 866 | def get_key_from_fp (replyinfo_obj, gpgme_ctx): |
39e2c525 AE |
867 | """Obtains a public key object from a key fingerprint |
868 | ||
ca37d0cb AE |
869 | If the .target_key is not set, then we use .fallback_target_key, if |
870 | available. | |
39e2c525 AE |
871 | |
872 | Args: | |
873 | replyinfo_obj: ReplyInfo instance | |
874 | gpgme_ctx: the gpgme context | |
875 | ||
876 | Return: | |
877 | The key object of the key of either the target_key or the fallback one | |
878 | if .target_key is not set. If the key cannot be loaded, then return | |
879 | None. | |
880 | ||
881 | Pre: | |
882 | Loading a key requires that we have the public key imported. This | |
883 | requires that they email contains the pub key block, or that it was | |
884 | previously sent to edward. | |
885 | ||
886 | Post: | |
ca37d0cb AE |
887 | If the key can be loaded, then replyinfo_obj.reply_to_key points to the |
888 | public key object. If the key cannot be loaded, then the replyinfo_obj | |
889 | is marked as having no public key available. | |
39e2c525 | 890 | """ |
013f7cb8 | 891 | |
ca37d0cb AE |
892 | for key in (replyinfo_obj.target_key, replyinfo_obj.fallback_target_key): |
893 | if key != None: | |
894 | try: | |
895 | encrypt_to_key = gpgme_ctx.get_key(key) | |
896 | replyinfo_obj.encrypt_to_key = encrypt_to_key | |
b4c116d5 | 897 | replyinfo_obj.have_reply_key = True |
ca37d0cb | 898 | return |
013f7cb8 | 899 | |
ca37d0cb AE |
900 | except gpgme.GpgmeError: |
901 | pass | |
013f7cb8 | 902 | |
013f7cb8 | 903 | |
d873ff48 | 904 | def write_reply (replyinfo_obj): |
39e2c525 AE |
905 | """Write the reply email body about the GPG successes/failures. |
906 | ||
907 | The reply is about whether decryption, sig verification and key | |
908 | import/loading was successful or failed. If text was successfully decrypted | |
909 | and verified, then the first instance of such text will be included in | |
910 | quoted form. | |
911 | ||
912 | Args: | |
913 | replyinfo_obj: contains details of GPG processing status | |
914 | ||
915 | Returns: | |
916 | the plaintext message to be sent to the user | |
917 | ||
918 | Pre: | |
919 | replyinfo_obj should be populated with info about GPG processing status. | |
920 | """ | |
d873ff48 AE |
921 | |
922 | reply_plain = "" | |
923 | ||
cfcc211c AE |
924 | if (replyinfo_obj.pubkey_success == True): |
925 | reply_plain += replyinfo_obj.replies['greeting'] | |
926 | reply_plain += "\n\n" | |
927 | ||
b4c116d5 | 928 | if replyinfo_obj.decrypt_success == True: |
234f607b | 929 | debug('decrypt success') |
d873ff48 | 930 | reply_plain += replyinfo_obj.replies['success_decrypt'] |
2694709a | 931 | |
b4c116d5 | 932 | if (replyinfo_obj.sig_success == True) and (replyinfo_obj.have_reply_key == True): |
234f607b | 933 | debug('message quoted') |
cfcc211c AE |
934 | reply_plain += replyinfo_obj.replies['space'] |
935 | reply_plain += replyinfo_obj.replies['quote_follows'] | |
936 | reply_plain += "\n\n" | |
2694709a AE |
937 | quoted_text = email_quote_text(replyinfo_obj.msg_to_quote) |
938 | reply_plain += quoted_text | |
cfcc211c AE |
939 | |
940 | reply_plain += "\n\n" | |
d873ff48 | 941 | |
4e2c66f7 | 942 | elif replyinfo_obj.decrypt_failure == True: |
234f607b | 943 | debug('decrypt failure') |
d873ff48 | 944 | reply_plain += replyinfo_obj.replies['failed_decrypt'] |
b4c116d5 | 945 | reply_plain += "\n\n" |
d873ff48 AE |
946 | |
947 | if replyinfo_obj.sig_success == True: | |
234f607b | 948 | debug('signature success') |
d873ff48 | 949 | reply_plain += replyinfo_obj.replies['sig_success'] |
b4c116d5 | 950 | reply_plain += "\n\n" |
d873ff48 | 951 | |
32a8996f | 952 | elif replyinfo_obj.sig_failure == True: |
234f607b | 953 | debug('signature failure') |
d873ff48 | 954 | reply_plain += replyinfo_obj.replies['sig_failure'] |
b4c116d5 | 955 | reply_plain += "\n\n" |
d873ff48 | 956 | |
b4c116d5 | 957 | if (replyinfo_obj.pubkey_success == True): |
234f607b | 958 | debug('public key received') |
b4c116d5 | 959 | reply_plain += replyinfo_obj.replies['public_key_received'] |
d873ff48 | 960 | reply_plain += "\n\n" |
d873ff48 | 961 | |
b4c116d5 | 962 | elif (replyinfo_obj.sigkey_missing == True): |
234f607b | 963 | debug('no public key') |
b4c116d5 | 964 | reply_plain += replyinfo_obj.replies['no_public_key'] |
d873ff48 | 965 | reply_plain += "\n\n" |
d873ff48 AE |
966 | |
967 | ||
4e2c66f7 AE |
968 | if (reply_plain == ""): |
969 | debug('plaintext message') | |
970 | reply_plain += replyinfo_obj.replies['failed_decrypt'] | |
971 | reply_plain += "\n\n" | |
972 | ||
973 | ||
d873ff48 | 974 | reply_plain += replyinfo_obj.replies['signature'] |
b4c116d5 | 975 | reply_plain += "\n\n" |
56578eaf | 976 | |
d873ff48 | 977 | return reply_plain |
56578eaf AE |
978 | |
979 | ||
8f61c66a | 980 | def add_gpg_key (key_block, gpgme_ctx): |
39e2c525 AE |
981 | """Adds a GPG pubkey to the local keystore |
982 | ||
983 | This adds keys received through email into the key store so they can be | |
984 | used later. | |
985 | ||
986 | Args: | |
987 | key_block: the string form of the ascii-armored public key block | |
988 | gpgme_ctx: the gpgme context | |
989 | ||
990 | Returns: | |
991 | the fingerprint(s) of the imported key(s) | |
992 | """ | |
c267c233 | 993 | |
8f61c66a | 994 | fp = io.BytesIO(key_block.encode('ascii')) |
c267c233 | 995 | |
89c08329 AE |
996 | try: |
997 | result = gpgme_ctx.import_(fp) | |
998 | imports = result.imports | |
999 | except gpgme.GpgmeError: | |
1000 | imports = [] | |
c267c233 | 1001 | |
f8ee6bd3 | 1002 | key_fingerprints = [] |
c267c233 | 1003 | |
8f61c66a AE |
1004 | if imports != []: |
1005 | for import_ in imports: | |
1006 | fingerprint = import_[0] | |
f8ee6bd3 | 1007 | key_fingerprints += [fingerprint] |
c267c233 | 1008 | |
e49673aa | 1009 | debug("added gpg key: " + fingerprint) |
ec1e779a | 1010 | |
f8ee6bd3 | 1011 | return key_fingerprints |
ec1e779a AE |
1012 | |
1013 | ||
3a753fd0 | 1014 | def verify_sig_message (msg_block, gpgme_ctx): |
39e2c525 AE |
1015 | """Verifies the signature of a signed, ascii-armored block of text. |
1016 | ||
1017 | It encodes the string into ascii, since binary GPG files are currently | |
1018 | unsupported, and alternative, the ascii-armored format is encodable into | |
1019 | ascii. | |
1020 | ||
1021 | Args: | |
1022 | msg_block: a GPG Message block in string form. It may be encrypted or | |
1023 | not. If it is encrypted, it will return empty results. | |
1024 | gpgme_ctx: the gpgme context | |
1025 | ||
1026 | Returns: | |
85a829fc | 1027 | A tuple containing the plaintext bytes of the signed part, the list of |
9af26cb8 | 1028 | fingerprints of keys signing the data, and a boolean marking whether |
b4c116d5 AE |
1029 | edward is missing all public keys for validating any of the signatures. |
1030 | If verification failed, perhaps because the message was also encrypted, | |
1031 | then empty results are returned. | |
39e2c525 | 1032 | """ |
3a753fd0 AE |
1033 | |
1034 | block_b = io.BytesIO(msg_block.encode('ascii')) | |
1035 | plain_b = io.BytesIO() | |
1036 | ||
1037 | try: | |
1038 | sigs = gpgme_ctx.verify(block_b, None, plain_b) | |
5f6f32b1 | 1039 | except gpgme.GpgmeError: |
b4c116d5 | 1040 | return ("",[],False) |
3a753fd0 | 1041 | |
85a829fc | 1042 | plaintext_b = plain_b.getvalue() |
3a753fd0 | 1043 | |
b4c116d5 | 1044 | sigkey_missing = False |
3a753fd0 AE |
1045 | fingerprints = [] |
1046 | for sig in sigs: | |
8f011cc9 | 1047 | if (sig.summary == 0) or (sig.summary & gpgme.SIGSUM_VALID != 0) or (sig.summary & gpgme.SIGSUM_GREEN != 0): |
9af26cb8 | 1048 | fingerprints += [sig.fpr] |
b4c116d5 AE |
1049 | sigkey_missing = False |
1050 | break | |
9af26cb8 | 1051 | else: |
b4c116d5 AE |
1052 | if (sig.summary & gpgme.SIGSUM_KEY_MISSING != 0): |
1053 | sigkey_missing = True | |
9af26cb8 | 1054 | |
85a829fc | 1055 | return (plaintext_b, fingerprints, sigkey_missing) |
3a753fd0 AE |
1056 | |
1057 | ||
101d54a8 | 1058 | def verify_detached_signature (detached_sig, plaintext_bytes, gpgme_ctx): |
39e2c525 AE |
1059 | """Verifies the signature of a detached signature. |
1060 | ||
1061 | This requires the signature part and the signed part as separate arguments. | |
1062 | ||
1063 | Args: | |
1064 | detached_sig: the signature part of the detached signature | |
1065 | plaintext_bytes: the byte form of the message being signed. | |
1066 | gpgme_ctx: the gpgme context | |
1067 | ||
1068 | Returns: | |
9af26cb8 | 1069 | A tuple containging a list of signing fingerprints if the signature |
b4c116d5 AE |
1070 | verification was sucessful, and a boolean marking whether edward is |
1071 | missing all public keys for validating any of the signatures. | |
1072 | Otherwise, a tuple containing an empty list and True are returned. | |
39e2c525 | 1073 | """ |
101d54a8 AE |
1074 | |
1075 | detached_sig_fp = io.BytesIO(detached_sig.encode('ascii')) | |
1076 | plaintext_fp = io.BytesIO(plaintext_bytes) | |
101d54a8 | 1077 | |
ff7aeb3d AE |
1078 | try: |
1079 | result = gpgme_ctx.verify(detached_sig_fp, plaintext_fp, None) | |
1080 | except gpgme.GpgmeError: | |
b4c116d5 | 1081 | return ([],False) |
101d54a8 | 1082 | |
b4c116d5 | 1083 | sigkey_missing = False |
101d54a8 AE |
1084 | sig_fingerprints = [] |
1085 | for res_ in result: | |
8f011cc9 | 1086 | if (res_.summary == 0) or (res_.summary & gpgme.SIGSUM_VALID != 0) or (res_.summary & gpgme.SIGSUM_GREEN != 0): |
9af26cb8 | 1087 | sig_fingerprints += [res_.fpr] |
b4c116d5 AE |
1088 | sigkey_missing = False |
1089 | break | |
9af26cb8 | 1090 | else: |
b4c116d5 AE |
1091 | if (res_.summary & gpgme.SIGSUM_KEY_MISSING != 0): |
1092 | sigkey_missing = True | |
101d54a8 | 1093 | |
b4c116d5 | 1094 | return (sig_fingerprints, sigkey_missing) |
101d54a8 AE |
1095 | |
1096 | ||
5b3053c1 | 1097 | def decrypt_block (msg_block, gpgme_ctx): |
9af26cb8 | 1098 | """Decrypts a block of GPG text and verifies any included sigatures. |
39e2c525 AE |
1099 | |
1100 | Some encypted messages have embeded signatures, so those are verified too. | |
1101 | ||
1102 | Args: | |
1103 | msg_block: the encrypted(/signed) text | |
1104 | gpgme_ctx: the gpgme context | |
1105 | ||
1106 | Returns: | |
85a829fc | 1107 | A tuple containing plaintext bytes, signatures (if the decryption and |
9af26cb8 | 1108 | signature verification were successful, respectively), and a boolean |
b4c116d5 AE |
1109 | marking whether edward is missing all public keys for validating any of |
1110 | the signatures. | |
39e2c525 | 1111 | """ |
0bec96d6 | 1112 | |
5b3053c1 | 1113 | block_b = io.BytesIO(msg_block.encode('ascii')) |
0bec96d6 AE |
1114 | plain_b = io.BytesIO() |
1115 | ||
afc1f64c AE |
1116 | try: |
1117 | sigs = gpgme_ctx.decrypt_verify(block_b, plain_b) | |
5f6f32b1 | 1118 | except gpgme.GpgmeError: |
b4c116d5 | 1119 | return ("",[],False) |
0bec96d6 | 1120 | |
85a829fc | 1121 | plaintext_b = plain_b.getvalue() |
cbdf22c1 | 1122 | |
b4c116d5 | 1123 | sigkey_missing = False |
cbdf22c1 AE |
1124 | fingerprints = [] |
1125 | for sig in sigs: | |
8f011cc9 | 1126 | if (sig.summary == 0) or (sig.summary & gpgme.SIGSUM_VALID != 0) or (sig.summary & gpgme.SIGSUM_GREEN != 0): |
9af26cb8 | 1127 | fingerprints += [sig.fpr] |
b4c116d5 AE |
1128 | sigkey_missing = False |
1129 | break | |
9af26cb8 | 1130 | else: |
b4c116d5 AE |
1131 | if (sig.summary & gpgme.SIGSUM_KEY_MISSING != 0): |
1132 | sigkey_missing = True | |
9af26cb8 | 1133 | |
85a829fc | 1134 | return (plaintext_b, fingerprints, sigkey_missing) |
0bec96d6 AE |
1135 | |
1136 | ||
85a829fc | 1137 | def email_to_from_subject (email_bytes): |
dd2b62d7 | 1138 | """Returns the values of the email's To:, From: and Subject: fields |
fafa21c3 | 1139 | |
dd2b62d7 | 1140 | Returns this information from an email. |
fafa21c3 | 1141 | |
dd2b62d7 | 1142 | Args: |
85a829fc | 1143 | email_bytes: the byte string form of the email |
fafa21c3 | 1144 | |
dd2b62d7 AE |
1145 | Returns: |
1146 | the email To:, From:, and Subject: fields as strings | |
1147 | """ | |
d65993b8 | 1148 | |
85a829fc | 1149 | email_struct = email.parser.BytesParser().parsebytes(email_bytes) |
d65993b8 AE |
1150 | |
1151 | email_to = email_struct['To'] | |
1152 | email_from = email_struct['From'] | |
1153 | email_subject = email_struct['Subject'] | |
1154 | ||
1155 | return email_to, email_from, email_subject | |
1156 | ||
1157 | ||
bb27d257 AE |
1158 | def import_lang_pick_address(email_to, hostname): |
1159 | """Imports language file for i18n support; makes reply from address | |
dd2b62d7 AE |
1160 | |
1161 | The language imported depends on the To: address of the email received by | |
1162 | edward. an -en ending implies the English language, whereas a -ja ending | |
1163 | implies Japanese. The list of supported languages is listed in the 'langs' | |
bb27d257 AE |
1164 | list at the beginning of the program. This function also chooses the |
1165 | language-dependent address which can be used as the From address in the | |
1166 | reply email. | |
dd2b62d7 AE |
1167 | |
1168 | Args: | |
1169 | email_to: the string containing the email address that the mail was | |
bb27d257 AE |
1170 | sent to. |
1171 | hostname: the hostname part of the reply email's from address | |
dd2b62d7 AE |
1172 | |
1173 | Returns: | |
1174 | the reference to the imported language module. The only variable in | |
1175 | this file is the 'replies' dictionary. | |
1176 | """ | |
adcef2f7 | 1177 | |
bb27d257 AE |
1178 | # default |
1179 | use_lang = "en" | |
daed5f10 | 1180 | |
5250b3b8 AE |
1181 | if email_to != None: |
1182 | for lang in langs: | |
1183 | if "edward-" + lang in email_to: | |
bb27d257 AE |
1184 | use_lang = lang |
1185 | break | |
adcef2f7 | 1186 | |
bb27d257 AE |
1187 | lang_mod_name = "lang." + re.sub('-', '_', use_lang) |
1188 | lang_module = importlib.import_module(lang_mod_name) | |
1189 | ||
60ccbaf4 | 1190 | reply_from = "edward-" + use_lang + "@" + hostname |
bb27d257 | 1191 | |
60ccbaf4 | 1192 | return lang_module, reply_from |
adcef2f7 AE |
1193 | |
1194 | ||
cfb03389 | 1195 | def generate_encrypted_mime (plaintext, email_to, email_subject, encrypt_to_key, |
0a064403 | 1196 | gpgme_ctx): |
dd2b62d7 AE |
1197 | """This function creates the mime email reply. It can encrypt the email. |
1198 | ||
1199 | If the encrypt_key is included, then the email is encrypted and signed. | |
1200 | Otherwise it is unencrypted. | |
1201 | ||
1202 | Args: | |
1203 | plaintext: the plaintext body of the message to create. | |
cfb03389 | 1204 | email_to: the email address to reply to |
dd2b62d7 AE |
1205 | email_subject: the subject to use in reply |
1206 | encrypt_to_key: the key object to use for encrypting the email. (or | |
1207 | None) | |
1208 | gpgme_ctx: the gpgme context | |
1209 | ||
1210 | Returns | |
1211 | A string version of the mime message, possibly encrypted and signed. | |
1212 | """ | |
1da9b527 | 1213 | |
e5dd6f23 | 1214 | if (encrypt_to_key != None): |
8bdfb6d4 | 1215 | |
66a125ef AE |
1216 | plaintext_mime = MIMEText(plaintext) |
1217 | plaintext_mime.set_charset('utf-8') | |
8bdfb6d4 AE |
1218 | |
1219 | encrypted_text = encrypt_sign_message(plaintext_mime.as_string(), | |
1220 | encrypt_to_key, | |
40c37ab3 | 1221 | gpgme_ctx) |
8bdfb6d4 | 1222 | |
e5dd6f23 AE |
1223 | control_mime = MIMEApplication("Version: 1", |
1224 | _subtype='pgp-encrypted', | |
1225 | _encoder=email.encoders.encode_7or8bit) | |
1226 | control_mime['Content-Description'] = 'PGP/MIME version identification' | |
1227 | control_mime.set_charset('us-ascii') | |
8bdfb6d4 | 1228 | |
e5dd6f23 AE |
1229 | encoded_mime = MIMEApplication(encrypted_text, |
1230 | _subtype='octet-stream; name="encrypted.asc"', | |
1231 | _encoder=email.encoders.encode_7or8bit) | |
1232 | encoded_mime['Content-Description'] = 'OpenPGP encrypted message' | |
1233 | encoded_mime['Content-Disposition'] = 'inline; filename="encrypted.asc"' | |
1234 | encoded_mime.set_charset('us-ascii') | |
8bdfb6d4 | 1235 | |
e5dd6f23 AE |
1236 | message_mime = MIMEMultipart(_subtype="encrypted", protocol="application/pgp-encrypted") |
1237 | message_mime.attach(control_mime) | |
1238 | message_mime.attach(encoded_mime) | |
1239 | message_mime['Content-Disposition'] = 'inline' | |
216708e9 | 1240 | |
e5dd6f23 AE |
1241 | else: |
1242 | message_mime = MIMEText(plaintext) | |
66a125ef | 1243 | message_mime.set_charset('utf-8') |
2007103e | 1244 | |
cfb03389 | 1245 | message_mime['To'] = email_to |
2007103e AE |
1246 | message_mime['Subject'] = email_subject |
1247 | ||
1248 | reply = message_mime.as_string() | |
1da9b527 AE |
1249 | |
1250 | return reply | |
1251 | ||
1252 | ||
60ccbaf4 AE |
1253 | def send_reply(email_txt, subject, reply_to, reply_from): |
1254 | ||
1255 | email_bytes = email_txt.encode('ascii') | |
1256 | ||
1257 | p = subprocess.Popen(["/usr/sbin/sendmail", "-f", reply_from, "-F", "Edward, GPG Bot", "-i", reply_to], stdin=subprocess.PIPE) | |
1258 | ||
1259 | (stdout, stderr) = p.communicate(email_bytes) | |
1260 | ||
1261 | if stdout != None: | |
1262 | debug("sendmail stdout: " + str(stdout)) | |
1263 | if stderr != None: | |
1264 | error("sendmail stderr: " + str(stderr)) | |
1265 | ||
1266 | ||
f87041f8 | 1267 | def email_quote_text (text): |
dd2b62d7 AE |
1268 | """Quotes input text by inserting "> "s |
1269 | ||
1270 | This is useful for quoting a text for the reply message. It inserts "> " | |
1271 | strings at the beginning of lines. | |
1272 | ||
1273 | Args: | |
1274 | text: plain text to quote | |
1275 | ||
1276 | Returns: | |
1277 | Quoted text | |
1278 | """ | |
f87041f8 AE |
1279 | |
1280 | quoted_message = re.sub(r'^', r'> ', text, flags=re.MULTILINE) | |
1281 | ||
1282 | return quoted_message | |
1283 | ||
1284 | ||
0a064403 | 1285 | def encrypt_sign_message (plaintext, encrypt_to_key, gpgme_ctx): |
dd2b62d7 AE |
1286 | """Encrypts and signs plaintext |
1287 | ||
1288 | This encrypts and signs a message. | |
1289 | ||
1290 | Args: | |
1291 | plaintext: text to sign and ecrypt | |
1292 | encrypt_to_key: the key object to encrypt to | |
1293 | gpgme_ctx: the gpgme context | |
1294 | ||
1295 | Returns: | |
1296 | An encrypted and signed string of text | |
1297 | """ | |
897cbaf6 | 1298 | |
b33f601b | 1299 | # the plaintext should be mime encoded in an ascii-compatible form |
6aa41372 | 1300 | plaintext_bytes = io.BytesIO(plaintext.encode('ascii')) |
1da9b527 AE |
1301 | encrypted_bytes = io.BytesIO() |
1302 | ||
897cbaf6 | 1303 | gpgme_ctx.encrypt_sign([encrypt_to_key], gpgme.ENCRYPT_ALWAYS_TRUST, |
1da9b527 AE |
1304 | plaintext_bytes, encrypted_bytes) |
1305 | ||
6aa41372 | 1306 | encrypted_txt = encrypted_bytes.getvalue().decode('ascii') |
1da9b527 AE |
1307 | return encrypted_txt |
1308 | ||
1309 | ||
0a064403 | 1310 | def error (error_msg): |
dd2b62d7 AE |
1311 | """Write an error message to stdout |
1312 | ||
1313 | The error message includes the program name. | |
1314 | ||
1315 | Args: | |
1316 | error_msg: the message to print | |
1317 | ||
1318 | Returns: | |
1319 | Nothing | |
1320 | ||
1321 | Post: | |
1322 | An error message is printed to stdout | |
1323 | """ | |
0a064403 | 1324 | |
e4fb2ab2 | 1325 | sys.stderr.write(progname + ": " + str(error_msg) + "\n") |
0a064403 AE |
1326 | |
1327 | ||
5e8f9094 | 1328 | def debug (debug_msg): |
dd2b62d7 AE |
1329 | """Writes a debug message to stdout if debug == True |
1330 | ||
1331 | If the debug option is set in edward_config.py, then the passed message | |
1332 | gets printed to stdout. | |
1333 | ||
1334 | Args: | |
1335 | debug_msg: the message to print to stdout | |
1336 | ||
1337 | Returns: | |
1338 | Nothing | |
1339 | ||
1340 | Post: | |
1341 | A debug message is printed to stdout | |
1342 | """ | |
5e8f9094 AE |
1343 | |
1344 | if edward_config.debug == True: | |
0a064403 | 1345 | error(debug_msg) |
5e8f9094 AE |
1346 | |
1347 | ||
20f6e7c5 | 1348 | def handle_args (): |
60ccbaf4 | 1349 | """Sets the progname variable and processes optional argument |
dd2b62d7 | 1350 | |
60ccbaf4 AE |
1351 | If there are more than two arguments then edward complains and quits. An |
1352 | single "-p" argument sets the print_reply_only option, which makes edward | |
1353 | print email replies instead of mailing them. | |
dd2b62d7 AE |
1354 | |
1355 | Args: | |
1356 | None | |
1357 | ||
1358 | Returns: | |
60ccbaf4 AE |
1359 | True if edward should print arguments instead of mailing them, |
1360 | otherwise it returns False. | |
dd2b62d7 AE |
1361 | |
1362 | Post: | |
60ccbaf4 AE |
1363 | Exits with error 1 if there are more than two arguments, otherwise |
1364 | returns the print_reply_only option. | |
dd2b62d7 | 1365 | """ |
20f6e7c5 | 1366 | |
a51cdb72 AE |
1367 | global progname |
1368 | progname = sys.argv[0] | |
1369 | ||
60ccbaf4 AE |
1370 | print_reply_only = False |
1371 | ||
1372 | if len(sys.argv) > 2: | |
1373 | print(progname + " usage: " + progname + " [-p]\n\n" \ | |
1374 | + " -p print reply message to stdout, do not mail it\n", \ | |
1375 | file=sys.stderr) | |
a51cdb72 | 1376 | exit(1) |
20f6e7c5 | 1377 | |
60ccbaf4 AE |
1378 | elif (len(sys.argv) == 2) and (sys.argv[1] == "-p"): |
1379 | print_reply_only = True | |
1380 | ||
1381 | return print_reply_only | |
1382 | ||
20f6e7c5 | 1383 | |
a51cdb72 | 1384 | if __name__ == "__main__": |
dd2b62d7 | 1385 | """Executes main if this file is not loaded interactively""" |
20f6e7c5 | 1386 | |
a51cdb72 | 1387 | main() |
0bec96d6 | 1388 |