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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 | """ | |
34 | ||
35 | import sys | |
0bec96d6 AE |
36 | import gpgme |
37 | import re | |
38 | import io | |
40c37ab3 | 39 | import os |
0bec96d6 | 40 | |
8bdfb6d4 AE |
41 | import email.parser |
42 | import email.message | |
43 | import email.encoders | |
44 | ||
45 | from email.mime.multipart import MIMEMultipart | |
46 | from email.mime.application import MIMEApplication | |
47 | from email.mime.nonmultipart import MIMENonMultipart | |
48 | ||
40c37ab3 | 49 | import edward_config |
c96f3837 | 50 | |
0bec96d6 AE |
51 | def main (): |
52 | ||
20f6e7c5 | 53 | handle_args() |
0bec96d6 | 54 | |
c96f3837 | 55 | email_text = sys.stdin.read() |
65ed3800 AE |
56 | email_from, email_subject = email_from_subject(email_text) |
57 | ||
40c37ab3 AE |
58 | os.environ['GNUPGHOME'] = edward_config.gnupghome |
59 | gpgme_ctx = gpgme.Context() | |
60 | gpgme_ctx.armor = True | |
61 | ||
c267c233 AE |
62 | add_gpg_keys(email_text, gpgme_ctx) |
63 | ||
40c37ab3 | 64 | plaintext, keys = email_decode_flatten(email_text, gpgme_ctx) |
1da9b527 | 65 | encrypt_to_key = choose_reply_encryption_key(keys) |
fafa21c3 | 66 | |
1da9b527 | 67 | reply_message = generate_reply(plaintext, email_from, \ |
897cbaf6 | 68 | email_subject, encrypt_to_key, |
40c37ab3 AE |
69 | edward_config.sign_with_key, |
70 | gpgme_ctx) | |
c96f3837 | 71 | |
1da9b527 | 72 | print(reply_message) |
c96f3837 | 73 | |
0bec96d6 | 74 | |
40c37ab3 | 75 | def email_decode_flatten (email_text, gpgme_ctx): |
0bec96d6 | 76 | |
86663388 | 77 | body = "" |
394a1476 AE |
78 | keys = [] |
79 | ||
80 | email_struct = email.parser.Parser().parsestr(email_text) | |
81 | ||
82 | for subpart in email_struct.walk(): | |
8bb4b0d5 | 83 | |
394a1476 AE |
84 | payload, description, filename, content_type \ |
85 | = get_email_subpart_info(subpart) | |
0bec96d6 | 86 | |
394a1476 | 87 | if payload == "": |
8bb4b0d5 | 88 | continue |
0bec96d6 | 89 | |
394a1476 | 90 | if content_type == "multipart": |
d437f8b2 | 91 | continue |
0bec96d6 | 92 | |
394a1476 AE |
93 | if content_type == "application/pgp-encrypted": |
94 | if description == "PGP/MIME version identification": | |
8bb4b0d5 | 95 | if payload.strip() != "Version: 1": |
394a1476 AE |
96 | print(progname + ": Warning: unknown " \ |
97 | + description + ": " \ | |
20f6e7c5 | 98 | + payload.strip(), file=sys.stderr) |
8bb4b0d5 AE |
99 | continue |
100 | ||
d437f8b2 | 101 | |
394a1476 | 102 | if (filename == "encrypted.asc") or (content_type == "pgp/mime"): |
40c37ab3 | 103 | plaintext, more_keys = decrypt_text(payload, gpgme_ctx) |
0bec96d6 | 104 | |
394a1476 AE |
105 | body += plaintext |
106 | keys += more_keys | |
107 | ||
c267c233 | 108 | elif content_type == "application/pgp-keys": |
ec1e779a | 109 | keys += add_gpg_keys(payload, gpgme_ctx) |
c267c233 | 110 | |
394a1476 | 111 | elif content_type == "text/plain": |
86663388 | 112 | body += payload + "\n" |
0bec96d6 | 113 | |
8bb4b0d5 | 114 | else: |
86663388 AE |
115 | body += payload + "\n" |
116 | ||
394a1476 | 117 | return body, keys |
86663388 | 118 | |
c96f3837 | 119 | |
65ed3800 | 120 | def email_from_subject (email_text): |
d437f8b2 | 121 | |
394a1476 | 122 | email_struct = email.parser.Parser().parsestr(email_text) |
d437f8b2 | 123 | |
394a1476 AE |
124 | email_from = email_struct['From'] |
125 | email_subject = email_struct['Subject'] | |
d437f8b2 | 126 | |
394a1476 | 127 | return email_from, email_subject |
d437f8b2 | 128 | |
d437f8b2 | 129 | |
394a1476 | 130 | def get_email_subpart_info (part): |
d437f8b2 | 131 | |
394a1476 AE |
132 | charset = part.get_content_charset() |
133 | payload_bytes = part.get_payload(decode=True) | |
d437f8b2 | 134 | |
394a1476 AE |
135 | filename = part.get_filename() |
136 | content_type = part.get_content_type() | |
137 | description_list = part.get_params(header='content-description') | |
d437f8b2 | 138 | |
394a1476 AE |
139 | if charset == None: |
140 | charset = 'utf-8' | |
0bec96d6 | 141 | |
394a1476 AE |
142 | if payload_bytes != None: |
143 | payload = payload_bytes.decode(charset) | |
144 | else: | |
145 | payload = "" | |
0bec96d6 | 146 | |
394a1476 AE |
147 | if description_list != None: |
148 | description = description_list[0][0] | |
149 | else: | |
150 | description = "" | |
0bec96d6 | 151 | |
394a1476 | 152 | return payload, description, filename, content_type |
0bec96d6 | 153 | |
0bec96d6 | 154 | |
c267c233 AE |
155 | def add_gpg_keys (text, gpgme_ctx): |
156 | ||
83210634 AE |
157 | key_blocks = scan_and_grab(text, |
158 | '-----BEGIN PGP PUBLIC KEY BLOCK-----', | |
159 | '-----END PGP PUBLIC KEY BLOCK-----') | |
c267c233 | 160 | |
83210634 AE |
161 | keys = [] |
162 | for key_block in key_blocks: | |
163 | fp = io.BytesIO(key_block.encode('ascii')) | |
c267c233 AE |
164 | |
165 | result = gpgme_ctx.import_(fp) | |
e49673aa | 166 | imports = result.imports |
c267c233 | 167 | |
e49673aa AE |
168 | if imports != []: |
169 | fingerprint = imports[0][0] | |
170 | keys += [gpgme_ctx.get_key(fingerprint)] | |
c267c233 | 171 | |
e49673aa | 172 | debug("added gpg key: " + fingerprint) |
ec1e779a | 173 | |
83210634 | 174 | return keys |
ec1e779a AE |
175 | |
176 | ||
40c37ab3 | 177 | def decrypt_text (gpg_text, gpgme_ctx): |
86663388 | 178 | |
394a1476 AE |
179 | body = "" |
180 | keys = [] | |
0bec96d6 | 181 | |
5b3053c1 | 182 | msg_blocks = scan_and_grab(gpg_text, |
c267c233 AE |
183 | '-----BEGIN PGP MESSAGE-----', |
184 | '-----END PGP MESSAGE-----') | |
86663388 | 185 | |
5b3053c1 | 186 | plaintexts_and_sigs = decrypt_blocks(msg_blocks, gpgme_ctx) |
0bec96d6 | 187 | |
5b3053c1 AE |
188 | for pair in plaintexts_and_sigs: |
189 | plaintext = pair[0] | |
190 | sigs = pair[1] | |
9eb78301 | 191 | |
394a1476 | 192 | for sig in sigs: |
5b3053c1 | 193 | keys += [gpgme_ctx.get_key(sig.fpr)] |
0bec96d6 | 194 | |
394a1476 | 195 | # recursive for nested layers of mime and/or gpg |
40c37ab3 | 196 | plaintext, more_keys = email_decode_flatten(plaintext, gpgme_ctx) |
8bb4b0d5 | 197 | |
394a1476 AE |
198 | body += plaintext |
199 | keys += more_keys | |
8bb4b0d5 | 200 | |
394a1476 | 201 | return body, keys |
8bb4b0d5 | 202 | |
8bb4b0d5 | 203 | |
c267c233 | 204 | def scan_and_grab (text, start_text, end_text): |
0bec96d6 | 205 | |
c267c233 AE |
206 | matches = re.search('(' + start_text + '.*' + end_text + ')', |
207 | text, flags=re.DOTALL) | |
0bec96d6 | 208 | |
c267c233 AE |
209 | if matches != None: |
210 | match_tuple = matches.groups() | |
0bec96d6 | 211 | else: |
c267c233 | 212 | match_tuple = () |
7b06b980 | 213 | |
c267c233 | 214 | return match_tuple |
0bec96d6 AE |
215 | |
216 | ||
5b3053c1 | 217 | def decrypt_blocks (msg_blocks, gpgme_ctx): |
0bec96d6 | 218 | |
5b3053c1 | 219 | return [decrypt_block(block, gpgme_ctx) for block in msg_blocks] |
0bec96d6 | 220 | |
0bec96d6 | 221 | |
5b3053c1 | 222 | def decrypt_block (msg_block, gpgme_ctx): |
0bec96d6 | 223 | |
5b3053c1 | 224 | block_b = io.BytesIO(msg_block.encode('ascii')) |
0bec96d6 AE |
225 | plain_b = io.BytesIO() |
226 | ||
afc1f64c AE |
227 | try: |
228 | sigs = gpgme_ctx.decrypt_verify(block_b, plain_b) | |
229 | except: | |
230 | return ("",[]) | |
0bec96d6 | 231 | |
6aa41372 | 232 | plaintext = plain_b.getvalue().decode('utf-8') |
394a1476 | 233 | return (plaintext, sigs) |
0bec96d6 AE |
234 | |
235 | ||
fafa21c3 AE |
236 | def choose_reply_encryption_key (keys): |
237 | ||
238 | reply_key = None | |
239 | for key in keys: | |
240 | if (key.can_encrypt == True): | |
241 | reply_key = key | |
242 | break | |
243 | ||
216708e9 | 244 | return reply_key |
fafa21c3 AE |
245 | |
246 | ||
897cbaf6 | 247 | def generate_reply (plaintext, email_from, email_subject, encrypt_to_key, |
40c37ab3 | 248 | sign_with_fingerprint, gpgme_ctx): |
1da9b527 | 249 | |
8bdfb6d4 | 250 | |
1da9b527 AE |
251 | reply = "To: " + email_from + "\n" |
252 | reply += "Subject: " + email_subject + "\n" | |
216708e9 AE |
253 | |
254 | if (encrypt_to_key != None): | |
255 | plaintext_reply = "thanks for the message!\n\n\n" | |
256 | plaintext_reply += email_quote_text(plaintext) | |
257 | ||
8bdfb6d4 AE |
258 | # quoted printable encoding lets most ascii characters look normal |
259 | # before the decrypted mime message is decoded. | |
260 | char_set = email.charset.Charset("utf-8") | |
261 | char_set.body_encoding = email.charset.QP | |
262 | ||
263 | # MIMEText doesn't allow setting the text encoding | |
264 | # so we use MIMENonMultipart. | |
265 | plaintext_mime = MIMENonMultipart('text', 'plain') | |
266 | plaintext_mime.set_payload(plaintext_reply, charset=char_set) | |
267 | ||
268 | encrypted_text = encrypt_sign_message(plaintext_mime.as_string(), | |
269 | encrypt_to_key, | |
40c37ab3 AE |
270 | sign_with_fingerprint, |
271 | gpgme_ctx) | |
8bdfb6d4 AE |
272 | |
273 | control_mime = MIMEApplication("Version: 1", | |
274 | _subtype='pgp-encrypted', | |
275 | _encoder=email.encoders.encode_7or8bit) | |
276 | control_mime['Content-Description'] = 'PGP/MIME version identification' | |
277 | control_mime.set_charset('us-ascii') | |
278 | ||
279 | encoded_mime = MIMEApplication(encrypted_text, | |
280 | _subtype='octet-stream; name="encrypted.asc"', | |
281 | _encoder=email.encoders.encode_7or8bit) | |
282 | encoded_mime['Content-Description'] = 'OpenPGP encrypted message' | |
283 | encoded_mime['Content-Disposition'] = 'inline; filename="encrypted.asc"' | |
284 | encoded_mime.set_charset('us-ascii') | |
285 | ||
286 | message_mime = MIMEMultipart(_subtype="encrypted", protocol="application/pgp-encrypted") | |
287 | message_mime.attach(control_mime) | |
288 | message_mime.attach(encoded_mime) | |
289 | message_mime['Content-Disposition'] = 'inline' | |
216708e9 | 290 | |
8bdfb6d4 | 291 | reply += message_mime.as_string() |
216708e9 AE |
292 | |
293 | else: | |
8bdfb6d4 | 294 | reply += "\n" |
216708e9 AE |
295 | reply += "Sorry, i couldn't find your key.\n" |
296 | reply += "I'll need that to encrypt a message to you." | |
1da9b527 AE |
297 | |
298 | return reply | |
299 | ||
300 | ||
f87041f8 AE |
301 | def email_quote_text (text): |
302 | ||
303 | quoted_message = re.sub(r'^', r'> ', text, flags=re.MULTILINE) | |
304 | ||
305 | return quoted_message | |
306 | ||
307 | ||
40c37ab3 | 308 | def encrypt_sign_message (plaintext, encrypt_to_key, sign_with_fingerprint, gpgme_ctx): |
1da9b527 | 309 | |
897cbaf6 AE |
310 | sign_with_key = gpgme_ctx.get_key(sign_with_fingerprint) |
311 | gpgme_ctx.signers = [sign_with_key] | |
312 | ||
6aa41372 | 313 | plaintext_bytes = io.BytesIO(plaintext.encode('ascii')) |
1da9b527 AE |
314 | encrypted_bytes = io.BytesIO() |
315 | ||
897cbaf6 | 316 | gpgme_ctx.encrypt_sign([encrypt_to_key], gpgme.ENCRYPT_ALWAYS_TRUST, |
1da9b527 AE |
317 | plaintext_bytes, encrypted_bytes) |
318 | ||
6aa41372 | 319 | encrypted_txt = encrypted_bytes.getvalue().decode('ascii') |
1da9b527 AE |
320 | return encrypted_txt |
321 | ||
322 | ||
5e8f9094 AE |
323 | def debug (debug_msg): |
324 | ||
325 | if edward_config.debug == True: | |
326 | sys.stderr.write(debug_msg + "\n") | |
327 | ||
328 | ||
20f6e7c5 AE |
329 | def handle_args (): |
330 | if __name__ == "__main__": | |
331 | ||
332 | global progname | |
333 | progname = sys.argv[0] | |
334 | ||
335 | if len(sys.argv) > 1: | |
336 | print(progname + ": error, this program doesn't " \ | |
337 | "need any arguments.", file=sys.stderr) | |
338 | exit(1) | |
339 | ||
340 | ||
0bec96d6 AE |
341 | main() |
342 |