1 #! /usr/bin/env python3
2 # -*- coding: utf-8 -*-
3 """*********************************************************************
4 * Edward is free software: you can redistribute it and/or modify *
5 * it under the terms of the GNU Affero Public License as published by *
6 * the Free Software Foundation, either version 3 of the License, or *
7 * (at your option) any later version. *
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. *
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/>. *
17 * Copyright (C) 2014-2015 Andrew Engelbrecht (AGPLv3+) *
18 * Copyright (C) 2014 Josh Drake (AGPLv3+) *
19 * Copyright (C) 2014 Lisa Marie Maginnis (AGPLv3+) *
20 * Copyright (C) 2009-2015 Tails developers <tails@boum.org> ( GPLv3+) *
21 * Copyright (C) 2009 W. Trevor King <wking@drexel.edu> ( GPLv2+) *
23 * Special thanks to Josh Drake for writing the original edward bot! :) *
25 ************************************************************************
27 Code sourced from these projects:
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
47 from email
.mime
.text
import MIMEText
48 from email
.mime
.multipart
import MIMEMultipart
49 from email
.mime
.application
import MIMEApplication
50 from email
.mime
.nonmultipart
import MIMENonMultipart
54 langs
= ["de", "el", "en", "fr", "ja", "pt-br", "ro", "ru", "tr"]
56 """This list contains the abbreviated names of reply languages available to
59 class TxtType (enum
.Enum
):
67 match_pairs
= [(TxtType
.message
,
68 '-----BEGIN PGP MESSAGE-----.*?-----END PGP MESSAGE-----'),
70 '-----BEGIN PGP PUBLIC KEY BLOCK-----.*?-----END PGP PUBLIC KEY BLOCK-----'),
72 '-----BEGIN PGP SIGNATURE-----.*?-----END PGP SIGNATURE-----')]
74 """This list of tuples matches query names with re.search() queries used
75 to find GPG data for edward to process."""
78 class EddyMsg (object):
80 The EddyMsg class represents relevant parts of a mime message.
82 The represented message can be single-part or multi-part.
84 'multipart' is set to True if there are multiple mime parts.
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.
89 'payload_bytes' is a binary representation of the mime part before header
90 removal and message decoding.
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.
95 The 'filename', 'content_type' and 'description_list' come from the mime
107 description_list
= None
110 class PayloadPiece (object):
112 PayloadPiece represents a complte or sub-section of a mime part.
114 Instances of this class are often strung together within one or more arrays
115 pointed to by each instance of the EddyMsg class.
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.
123 'string' contains some string of text, such as non-GPG text, an encrypted
124 block of text, a signature, or a public key.
126 'gpg_data' points to any instances of GPGData that have been created based
127 on the contents of 'string'.
135 class GPGData (object):
137 GPGData holds info from decryption, sig. verification, and/or pub. keys.
139 Instances of this class contain decrypted information, signature
140 fingerprints and/or fingerprints of processed and imported public keys.
142 'decrypted' is set to True if 'plainobj' was created from encrypted data.
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.
147 'sigs' is a list of fingerprints of keys used to sign the data in plainobj.
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.
152 'keys' is a list of fingerprints of keys obtained in public key blocks.
159 sigkey_missing
= False
163 class ReplyInfo (object):
165 ReplyInfo contains details that edward uses in generating its reply.
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.
173 'replies' points one of the dictionaries of translated replies.
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.
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
182 'encrypt_to_key' the key object to use when encrypting edward's reply
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.
189 'decrypt_success' is set to True if edward could decrypt part of the
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.
195 'pubkey_success' is set to True if edward successfully imported a public
198 'sigkey_missing' is set to True if edward doesn't have the public key
199 needed for signature verification.
201 'have_repy_key' is set to True if edward has a public key to encrypt its
208 fallback_target_key
= None
209 encrypt_to_key
= None
212 decrypt_success
= False
214 pubkey_success
= False
216 sigkey_missing
= False
217 have_reply_key
= False
223 This is the main function for edward, a GPG reply bot.
225 Edward responds to GPG-encrypted and signed mail, encrypting and signing
226 the response if the user's public key is, or was, included in the message.
235 Mime or plaintext email passing in through standard input. Portions of
236 the email may be encrypted. If the To: address contains the text
237 "edward-ja", then the reply will contain a reply written in the
238 Japanese language. There are other languages as well. The default
242 A reply email will be printed to standard output. The contents of the
243 reply email depends on whether the original email was encrypted or not,
244 has or doesn't have a signature, whether a public key used in the
245 original message is provided or locally stored, and the language
246 implied by the To: address in the original email.
249 print_reply_only
= handle_args()
251 gpgme_ctx
= get_gpg_context(edward_config
.gnupghome
,
252 edward_config
.sign_with_key
)
254 email_text
= sys
.stdin
.read()
255 email_struct
= parse_pgp_mime(email_text
, gpgme_ctx
)
257 email_to
, email_from
, email_subject
= email_to_from_subject(email_text
)
258 lang
, reply_from
= import_lang_pick_address(email_to
, edward_config
.hostname
)
260 replyinfo_obj
= ReplyInfo()
261 replyinfo_obj
.replies
= lang
.replies
263 prepare_for_reply(email_struct
, replyinfo_obj
)
264 get_key_from_fp(replyinfo_obj
, gpgme_ctx
)
265 reply_plaintext
= write_reply(replyinfo_obj
)
267 reply_mime
= generate_encrypted_mime(reply_plaintext
, email_from
, \
268 email_subject
, replyinfo_obj
.encrypt_to_key
,
271 if print_reply_only
== True:
274 send_reply(reply_mime
, email_subject
, email_from
, reply_from
)
277 def get_gpg_context (gnupghome
, sign_with_key_fp
):
279 This function returns the GPG context needed for encryption and signing.
281 The context is needed by other functions which use GPG functionality.
284 gnupghome: The path to "~/.gnupg/" or its alternative.
285 sign_with_key: The fingerprint of the key to sign with
288 A gpgme context to be used for GPG functions.
291 the 'armor' flag is set to True and the list of signing keys contains
292 the single specified key
295 os
.environ
['GNUPGHOME'] = gnupghome
297 gpgme_ctx
= gpgme
.Context()
298 gpgme_ctx
.armor
= True
301 sign_with_key
= gpgme_ctx
.get_key(sign_with_key_fp
)
302 except gpgme
.GpgmeError
:
303 error("unable to load signing key. is the gnupghome "
304 + "and signing key properly set in the edward_config.py?")
307 gpgme_ctx
.signers
= [sign_with_key
]
312 def parse_pgp_mime (email_text
, gpgme_ctx
):
313 """Parses the email for mime payloads and decrypts/verfies signatures.
315 This function creates a representation of a mime or plaintext email with
316 the EddyMsg class. It then splits each mime payload into one or more pieces
317 which may be plain text or GPG data. It then decrypts encrypted parts and
318 does some very basic signature verification on those parts.
321 email_text: an email message in string format
322 gpgme_ctx: a gpgme context
325 A message as an instance of EddyMsg
328 the returned EddyMsg instance has split, decrypted, verified and pubkey
332 email_struct
= email
.parser
.Parser().parsestr(email_text
)
334 eddymsg_obj
= parse_mime(email_struct
)
335 split_payloads(eddymsg_obj
)
336 gpg_on_payloads(eddymsg_obj
, gpgme_ctx
)
341 def parse_mime(msg_struct
):
342 """Translates python's email.parser format into an EddyMsg format
344 If the message is multi-part, then a recursive object is created, where
345 each sub-part is also a EddyMsg instance.
348 msg_struct: an email parsed with email.parser.Parser(), which can be
352 an instance of EddyMsg, potentially a recursive one.
355 eddymsg_obj
= EddyMsg()
357 if msg_struct
.is_multipart() == True:
358 payloads
= msg_struct
.get_payload()
360 eddymsg_obj
.multipart
= True
361 eddymsg_obj
.subparts
= list(map(parse_mime
, payloads
))
364 eddymsg_obj
= get_subpart_data(msg_struct
)
369 def scan_and_split (payload_piece
, match_name
, pattern
):
370 """This splits the payloads of an EddyMsg object into GPG and text parts.
372 An EddyMsg object's payload_pieces starts off as a list containing a single
373 PayloadPiece object. This function returns a list of these objects which
374 have been split into GPG data and regular text, if such splits need to be/
378 payload_piece: a single payload or a split part of a payload
379 match_name: the type of data to try to spit out from the payload piece
380 pattern: the search pattern to be used for finding that type of data
383 a list of objects of the PayloadPiece class, in the order that the
384 string part of payload_piece originally was, broken up according to
385 matches specified by 'pattern'.
388 # don't try to re-split pieces containing gpg data
389 if payload_piece
.piece_type
!= TxtType
.text
:
390 return [payload_piece
]
392 flags
= re
.DOTALL | re
.MULTILINE
393 matches
= re
.search("(?P<beginning>.*?)(?P<match>" + pattern
+
394 ")(?P<rest>.*)", payload_piece
.string
, flags
=flags
)
397 pieces
= [payload_piece
]
401 beginning
= PayloadPiece()
402 beginning
.string
= matches
.group('beginning')
403 beginning
.piece_type
= payload_piece
.piece_type
405 match
= PayloadPiece()
406 match
.string
= matches
.group('match')
407 match
.piece_type
= match_name
409 rest
= PayloadPiece()
410 rest
.string
= matches
.group('rest')
411 rest
.piece_type
= payload_piece
.piece_type
413 more_pieces
= scan_and_split(rest
, match_name
, pattern
)
414 pieces
= [beginning
, match
] + more_pieces
419 def get_subpart_data (part
):
420 """This function grabs information from a single part mime object.
422 It copies needed data from a single part email.parser.Parser() object over
423 to an EddyMsg object.
426 part: a non-multi-part mime.parser.Parser() object
429 a single-part EddyMsg() object
432 charset
= part
.get_content_charset()
433 mime_decoded_bytes
= part
.get_payload(decode
=True)
436 obj
.payload_bytes
= part
.as_bytes()
438 obj
.filename
= part
.get_filename()
439 obj
.content_type
= part
.get_content_type()
440 obj
.description_list
= part
['content-description']
442 # your guess is as good as a-myy-ee-ine...
446 if mime_decoded_bytes
!= None:
448 payload
= PayloadPiece()
449 payload
.string
= mime_decoded_bytes
.decode(charset
)
450 payload
.piece_type
= TxtType
.text
452 obj
.payload_pieces
= [payload
]
453 except UnicodeDecodeError:
459 def do_to_eddys_pieces (function_to_do
, eddymsg_obj
, data
):
460 """A function which maps another function onto a message's subparts.
462 This is a higer-order function which recursively performs a specified
463 function on each subpart of a multi-part message. Each single-part sub-part
464 has the function applied to it. This function also works if the part passed
468 function_to_do: function to perform on sub-parts
469 eddymsg_obj: a single part or multi-part EddyMsg object
470 data: a second argument to pass to 'function_to_do'
476 The passed-in EddyMsg object is transformed recursively on its
477 sub-parts according to 'function_to_do'.
480 if eddymsg_obj
.multipart
== True:
481 for sub
in eddymsg_obj
.subparts
:
482 do_to_eddys_pieces(function_to_do
, sub
, data
)
484 function_to_do(eddymsg_obj
, data
)
487 def split_payloads (eddymsg_obj
):
488 """Splits all (sub-)payloads of a message into GPG data and regular text.
490 Recursively performs payload splitting on all sub-parts of an EddyMsg
491 object into the various GPG data types, such as GPG messages, public key
492 blocks and signed text.
495 eddymsg_obj: an instance of EddyMsg
501 The EddyMsg object has payloads that are unsplit (by may be split)..
504 The EddyMsg object's payloads are all split into GPG and non-GPG parts.
507 for match_pair
in match_pairs
:
508 do_to_eddys_pieces(split_payload_pieces
, eddymsg_obj
, match_pair
)
511 def split_payload_pieces (eddymsg_obj
, match_pair
):
512 """A helper function for split_payloads(); works on PayloadPiece objects.
514 This function splits up PayloadPiece objects into multipe PayloadPiece
515 objects and replaces the EddyMsg object's previous list of payload pieces
516 with the new split up one.
519 eddymsg_obj: a single-part EddyMsg object.
520 match_pair: a tuple from the match_pairs list, which specifies a match
521 name and a match pattern.
527 The payload piece(s) of an EddyMsg object may be already split or
531 The EddyMsg object's payload piece(s) are split into a list of pieces
532 if matches of the match_pair are found.
535 (match_name
, pattern
) = match_pair
538 for piece
in eddymsg_obj
.payload_pieces
:
539 new_pieces_list
+= scan_and_split(piece
, match_name
, pattern
)
541 eddymsg_obj
.payload_pieces
= new_pieces_list
544 def gpg_on_payloads (eddymsg_obj
, gpgme_ctx
, prev_parts
=[]):
545 """Performs GPG operations on the GPG parts of the message
547 This function decrypts text, verifies signatures, and imports public keys
548 included in an email.
551 eddymsg_obj: an EddyMsg object with its payload_pieces split into GPG
552 and non-GPG sections by split_payloads()
553 gpgme_ctx: a gpgme context
555 prev_parts: a list of mime parts that occur before the eddymsg_obj
556 part, under the same multi-part mime part. This is used for
557 verifying detached signatures. For the root mime part, this should
558 be an empty list, which is the default value if this paramater is
565 eddymsg_obj should have its payloads split into gpg and non-gpg pieces.
568 Decryption, verification and key imports occur. the gpg_data member of
569 PayloadPiece objects get filled in with GPGData objects.
572 if eddymsg_obj
.multipart
== True:
574 for sub
in eddymsg_obj
.subparts
:
575 gpg_on_payloads (sub
, gpgme_ctx
, prev_parts
)
580 for piece
in eddymsg_obj
.payload_pieces
:
582 if piece
.piece_type
== TxtType
.text
:
583 # don't transform the plaintext.
586 elif piece
.piece_type
== TxtType
.message
:
587 piece
.gpg_data
= GPGData()
589 (plaintext
, sigs
, sigkey_missing
) = decrypt_block(piece
.string
, gpgme_ctx
)
591 piece
.gpg_data
.sigkey_missing
= sigkey_missing
594 piece
.gpg_data
.decrypted
= True
595 piece
.gpg_data
.sigs
= sigs
597 piece
.gpg_data
.plainobj
= parse_pgp_mime(plaintext
, gpgme_ctx
)
600 # if not encrypted, check to see if this is an armored signature.
601 (plaintext
, sigs
, sigkey_missing
) = verify_sig_message(piece
.string
, gpgme_ctx
)
603 piece
.gpg_data
.sigkey_missing
= sigkey_missing
606 piece
.piece_type
= TxtType
.signature
607 piece
.gpg_data
.sigs
= sigs
609 piece
.gpg_data
.plainobj
= parse_pgp_mime(plaintext
, gpgme_ctx
)
611 elif piece
.piece_type
== TxtType
.pubkey
:
612 key_fps
= add_gpg_key(piece
.string
, gpgme_ctx
)
615 piece
.gpg_data
= GPGData()
616 piece
.gpg_data
.keys
= key_fps
618 elif piece
.piece_type
== TxtType
.detachedsig
:
619 piece
.gpg_data
= GPGData()
621 for prev
in prev_parts
:
622 (sig_fps
, sigkey_missing
) = verify_detached_signature(piece
.string
, prev
.payload_bytes
, gpgme_ctx
)
624 piece
.gpg_data
.sigkey_missing
= sigkey_missing
627 piece
.gpg_data
.sigs
= sig_fps
628 piece
.gpg_data
.plainobj
= prev
635 def prepare_for_reply (eddymsg_obj
, replyinfo_obj
):
636 """Updates replyinfo_obj with info on the message's GPG success/failures
638 This function marks replyinfo_obj with information about whether encrypted
639 text in eddymsg_obj was successfully decrypted, signatures were verified
640 and whether a public key was found or not.
643 eddymsg_obj: a message in the EddyMsg format
644 replyinfo_obj: an instance of ReplyInfo
650 eddymsg_obj has had its gpg_data created by gpg_on_payloads
653 replyinfo_obj has been updated with info about decryption/sig
654 verififcation status, etc. However the desired key isn't imported until
655 later, so the success or failure of that updates the values set here.
658 do_to_eddys_pieces(prepare_for_reply_pieces
, eddymsg_obj
, replyinfo_obj
)
660 def prepare_for_reply_pieces (eddymsg_obj
, replyinfo_obj
):
661 """A helper function for prepare_for_reply
663 It updates replyinfo_obj with GPG success/failure information, when
664 supplied a single-part EddyMsg object.
667 eddymsg_obj: a single-part message in the EddyMsg format
668 replyinfo_obj: an object which holds information about the message's
675 eddymsg_obj is a single-part message. (it may be a part of a multi-part
676 message.) It has had its gpg_data created by gpg_on_payloads if it has
680 replyinfo_obj has been updated with gpg success/failure information
683 for piece
in eddymsg_obj
.payload_pieces
:
684 if piece
.piece_type
== TxtType
.text
:
685 # don't quote the plaintext part.
688 elif piece
.piece_type
== TxtType
.message
:
689 prepare_for_reply_message(piece
, replyinfo_obj
)
691 elif piece
.piece_type
== TxtType
.pubkey
:
692 prepare_for_reply_pubkey(piece
, replyinfo_obj
)
694 elif (piece
.piece_type
== TxtType
.detachedsig
) \
695 or (piece
.piece_type
== TxtType
.signature
):
696 prepare_for_reply_sig(piece
, replyinfo_obj
)
699 def prepare_for_reply_message (piece
, replyinfo_obj
):
700 """Helper function for prepare_for_reply()
702 This function is called when the piece_type of a payload piece is
703 TxtType.message, or GPG Message block. This should be encrypted text. If
704 the encryted block is correclty signed, a sig will be attached to
705 .target_key unless there is already one there.
708 piece: a PayloadPiece object.
709 replyinfo_obj: object which gets updated with decryption status, etc.
715 the piece.payload_piece value should be TxtType.message.
718 replyinfo_obj gets updated with decryption status, signing status, a
719 potential signing key, and posession status of the public key for the
723 if piece
.gpg_data
== None or piece
.gpg_data
.plainobj
== None:
726 replyinfo_obj
.decrypt_success
= True
728 # we already have a key (and a message)
729 if replyinfo_obj
.target_key
!= None:
732 if piece
.gpg_data
.sigs
!= []:
733 replyinfo_obj
.target_key
= piece
.gpg_data
.sigs
[0]
734 replyinfo_obj
.sig_success
= True
735 get_signed_part
= False
738 if piece
.gpg_data
.sigkey_missing
== True:
739 replyinfo_obj
.sigkey_missing
= True
741 # only include a signed message in the reply.
742 get_signed_part
= True
744 flatten_decrypted_payloads(piece
.gpg_data
.plainobj
, replyinfo_obj
, get_signed_part
)
746 # to catch public keys in encrypted blocks
747 prepare_for_reply(piece
.gpg_data
.plainobj
, replyinfo_obj
)
750 def prepare_for_reply_pubkey (piece
, replyinfo_obj
):
751 """Helper function for prepare_for_reply(). Marks pubkey import status.
753 Marks replyinfo_obj with pub key import status.
756 piece: a PayloadPiece object
757 replyinfo_obj: a ReplyInfo object
760 piece.piece_type should be set to TxtType.pubkey .
763 replyinfo_obj has its fields updated.
766 if piece
.gpg_data
== None or piece
.gpg_data
.keys
== []:
769 replyinfo_obj
.pubkey_success
= True
771 # prefer public key as a fallback for the encrypted reply
772 replyinfo_obj
.fallback_target_key
= piece
.gpg_data
.keys
[0]
775 def prepare_for_reply_sig (piece
, replyinfo_obj
):
776 """Helper function for prepare_for_reply(). Marks sig verification status.
778 Marks replyinfo_obj with signature verification status.
781 piece: a PayloadPiece object
782 replyinfo_obj: a ReplyInfo object
785 piece.piece_type should be set to TxtType.signature, or
786 TxtType.detachedsig .
789 replyinfo_obj has its fields updated.
792 if piece
.gpg_data
== None or piece
.gpg_data
.sigs
== []:
794 if piece
.gpg_data
.sigkey_missing
== True:
795 replyinfo_obj
.sigkey_missing
= True
798 replyinfo_obj
.sig_success
= True
800 if replyinfo_obj
.fallback_target_key
== None:
801 replyinfo_obj
.fallback_target_key
= piece
.gpg_data
.sigs
[0]
804 def flatten_decrypted_payloads (eddymsg_obj
, replyinfo_obj
, get_signed_part
):
805 """For creating a string representation of a signed, encrypted part.
807 When given a decrypted payload, it will add either the plaintext or signed
808 plaintext to the reply message, depeding on 'get_signed_part'. This is
809 useful for ensuring that the reply message only comes from a signed and
810 ecrypted GPG message. It also sets the target_key for encrypting the reply
811 if it's told to get signed text only.
814 eddymsg_obj: the message in EddyMsg format created by decrypting GPG
816 replyinfo_obj: a ReplyInfo object for holding the message to quote and
817 the target_key to encrypt to.
818 get_signed_part: True if we should only include text that contains a
819 further signature. If False, then include plain text.
825 The EddyMsg instance passed in should be a piece.gpg_data.plainobj
826 which represents decrypted text. It may or may not be signed on that
830 the ReplyInfo instance may have a new 'target_key' set and its
831 'msg_to_quote' will be updated with (possibly signed) plaintext, if any
835 if eddymsg_obj
== None:
838 # recurse on multi-part mime
839 if eddymsg_obj
.multipart
== True:
840 for sub
in eddymsg_obj
.subparts
:
841 flatten_decrypted_payloads(sub
, replyinfo_obj
, get_signed_part
)
843 for piece
in eddymsg_obj
.payload_pieces
:
844 if (get_signed_part
):
845 if ((piece
.piece_type
== TxtType
.detachedsig
) \
846 or (piece
.piece_type
== TxtType
.signature
)) \
847 and (piece
.gpg_data
!= None) \
848 and (piece
.gpg_data
.plainobj
!= None):
849 flatten_decrypted_payloads(piece
.gpg_data
.plainobj
, replyinfo_obj
, False)
850 replyinfo_obj
.target_key
= piece
.gpg_data
.sigs
[0]
853 if piece
.piece_type
== TxtType
.text
:
854 replyinfo_obj
.msg_to_quote
+= piece
.string
857 def get_key_from_fp (replyinfo_obj
, gpgme_ctx
):
858 """Obtains a public key object from a key fingerprint
860 If the .target_key is not set, then we use .fallback_target_key, if
864 replyinfo_obj: ReplyInfo instance
865 gpgme_ctx: the gpgme context
868 The key object of the key of either the target_key or the fallback one
869 if .target_key is not set. If the key cannot be loaded, then return
873 Loading a key requires that we have the public key imported. This
874 requires that they email contains the pub key block, or that it was
875 previously sent to edward.
878 If the key can be loaded, then replyinfo_obj.reply_to_key points to the
879 public key object. If the key cannot be loaded, then the replyinfo_obj
880 is marked as having no public key available.
883 for key
in (replyinfo_obj
.target_key
, replyinfo_obj
.fallback_target_key
):
886 encrypt_to_key
= gpgme_ctx
.get_key(key
)
887 replyinfo_obj
.encrypt_to_key
= encrypt_to_key
888 replyinfo_obj
.have_reply_key
= True
891 except gpgme
.GpgmeError
:
895 def write_reply (replyinfo_obj
):
896 """Write the reply email body about the GPG successes/failures.
898 The reply is about whether decryption, sig verification and key
899 import/loading was successful or failed. If text was successfully decrypted
900 and verified, then the first instance of such text will be included in
904 replyinfo_obj: contains details of GPG processing status
907 the plaintext message to be sent to the user
910 replyinfo_obj should be populated with info about GPG processing status.
915 if replyinfo_obj
.decrypt_success
== True:
916 reply_plain
+= replyinfo_obj
.replies
['success_decrypt']
917 reply_plain
+= "\n\n"
919 if (replyinfo_obj
.sig_success
== True) and (replyinfo_obj
.have_reply_key
== True):
920 quoted_text
= email_quote_text(replyinfo_obj
.msg_to_quote
)
921 reply_plain
+= quoted_text
922 reply_plain
+= "\n\n"
925 reply_plain
+= replyinfo_obj
.replies
['failed_decrypt']
926 reply_plain
+= "\n\n"
928 if replyinfo_obj
.sig_success
== True:
929 reply_plain
+= replyinfo_obj
.replies
['sig_success']
930 reply_plain
+= "\n\n"
933 reply_plain
+= replyinfo_obj
.replies
['sig_failure']
934 reply_plain
+= "\n\n"
936 if (replyinfo_obj
.pubkey_success
== True):
937 reply_plain
+= replyinfo_obj
.replies
['public_key_received']
938 reply_plain
+= "\n\n"
940 elif (replyinfo_obj
.sigkey_missing
== True):
941 reply_plain
+= replyinfo_obj
.replies
['no_public_key']
942 reply_plain
+= "\n\n"
945 reply_plain
+= replyinfo_obj
.replies
['signature']
946 reply_plain
+= "\n\n"
951 def add_gpg_key (key_block
, gpgme_ctx
):
952 """Adds a GPG pubkey to the local keystore
954 This adds keys received through email into the key store so they can be
958 key_block: the string form of the ascii-armored public key block
959 gpgme_ctx: the gpgme context
962 the fingerprint(s) of the imported key(s)
965 fp
= io
.BytesIO(key_block
.encode('ascii'))
968 result
= gpgme_ctx
.import_(fp
)
969 imports
= result
.imports
970 except gpgme
.GpgmeError
:
973 key_fingerprints
= []
976 for import_
in imports
:
977 fingerprint
= import_
[0]
978 key_fingerprints
+= [fingerprint
]
980 debug("added gpg key: " + fingerprint
)
982 return key_fingerprints
985 def verify_sig_message (msg_block
, gpgme_ctx
):
986 """Verifies the signature of a signed, ascii-armored block of text.
988 It encodes the string into ascii, since binary GPG files are currently
989 unsupported, and alternative, the ascii-armored format is encodable into
993 msg_block: a GPG Message block in string form. It may be encrypted or
994 not. If it is encrypted, it will return empty results.
995 gpgme_ctx: the gpgme context
998 A tuple containing the plaintext of the signed part, the list of
999 fingerprints of keys signing the data, and a boolean marking whether
1000 edward is missing all public keys for validating any of the signatures.
1001 If verification failed, perhaps because the message was also encrypted,
1002 then empty results are returned.
1005 block_b
= io
.BytesIO(msg_block
.encode('ascii'))
1006 plain_b
= io
.BytesIO()
1009 sigs
= gpgme_ctx
.verify(block_b
, None, plain_b
)
1010 except gpgme
.GpgmeError
:
1011 return ("",[],False)
1013 plaintext
= plain_b
.getvalue().decode('utf-8')
1015 sigkey_missing
= False
1018 if (sig
.summary
== 0) or (sig
.summary
& gpgme
.SIGSUM_VALID
!= 0) or (sig
.summary
& gpgme
.SIGSUM_GREEN
!= 0):
1019 fingerprints
+= [sig
.fpr
]
1020 sigkey_missing
= False
1023 if (sig
.summary
& gpgme
.SIGSUM_KEY_MISSING
!= 0):
1024 sigkey_missing
= True
1026 return (plaintext
, fingerprints
, sigkey_missing
)
1029 def verify_detached_signature (detached_sig
, plaintext_bytes
, gpgme_ctx
):
1030 """Verifies the signature of a detached signature.
1032 This requires the signature part and the signed part as separate arguments.
1035 detached_sig: the signature part of the detached signature
1036 plaintext_bytes: the byte form of the message being signed.
1037 gpgme_ctx: the gpgme context
1040 A tuple containging a list of signing fingerprints if the signature
1041 verification was sucessful, and a boolean marking whether edward is
1042 missing all public keys for validating any of the signatures.
1043 Otherwise, a tuple containing an empty list and True are returned.
1046 detached_sig_fp
= io
.BytesIO(detached_sig
.encode('ascii'))
1047 plaintext_fp
= io
.BytesIO(plaintext_bytes
)
1050 result
= gpgme_ctx
.verify(detached_sig_fp
, plaintext_fp
, None)
1051 except gpgme
.GpgmeError
:
1054 sigkey_missing
= False
1055 sig_fingerprints
= []
1057 if (res_
.summary
== 0) or (res_
.summary
& gpgme
.SIGSUM_VALID
!= 0) or (res_
.summary
& gpgme
.SIGSUM_GREEN
!= 0):
1058 sig_fingerprints
+= [res_
.fpr
]
1059 sigkey_missing
= False
1062 if (res_
.summary
& gpgme
.SIGSUM_KEY_MISSING
!= 0):
1063 sigkey_missing
= True
1065 return (sig_fingerprints
, sigkey_missing
)
1068 def decrypt_block (msg_block
, gpgme_ctx
):
1069 """Decrypts a block of GPG text and verifies any included sigatures.
1071 Some encypted messages have embeded signatures, so those are verified too.
1074 msg_block: the encrypted(/signed) text
1075 gpgme_ctx: the gpgme context
1078 A tuple containing plaintext, signatures (if the decryption and
1079 signature verification were successful, respectively), and a boolean
1080 marking whether edward is missing all public keys for validating any of
1084 block_b
= io
.BytesIO(msg_block
.encode('ascii'))
1085 plain_b
= io
.BytesIO()
1088 sigs
= gpgme_ctx
.decrypt_verify(block_b
, plain_b
)
1089 except gpgme
.GpgmeError
:
1090 return ("",[],False)
1092 plaintext
= plain_b
.getvalue().decode('utf-8')
1094 sigkey_missing
= False
1097 if (sig
.summary
== 0) or (sig
.summary
& gpgme
.SIGSUM_VALID
!= 0) or (sig
.summary
& gpgme
.SIGSUM_GREEN
!= 0):
1098 fingerprints
+= [sig
.fpr
]
1099 sigkey_missing
= False
1102 if (sig
.summary
& gpgme
.SIGSUM_KEY_MISSING
!= 0):
1103 sigkey_missing
= True
1105 return (plaintext
, fingerprints
, sigkey_missing
)
1108 def email_to_from_subject (email_text
):
1109 """Returns the values of the email's To:, From: and Subject: fields
1111 Returns this information from an email.
1114 email_text: the string form of the email
1117 the email To:, From:, and Subject: fields as strings
1120 email_struct
= email
.parser
.Parser().parsestr(email_text
)
1122 email_to
= email_struct
['To']
1123 email_from
= email_struct
['From']
1124 email_subject
= email_struct
['Subject']
1126 return email_to
, email_from
, email_subject
1129 def import_lang_pick_address(email_to
, hostname
):
1130 """Imports language file for i18n support; makes reply from address
1132 The language imported depends on the To: address of the email received by
1133 edward. an -en ending implies the English language, whereas a -ja ending
1134 implies Japanese. The list of supported languages is listed in the 'langs'
1135 list at the beginning of the program. This function also chooses the
1136 language-dependent address which can be used as the From address in the
1140 email_to: the string containing the email address that the mail was
1142 hostname: the hostname part of the reply email's from address
1145 the reference to the imported language module. The only variable in
1146 this file is the 'replies' dictionary.
1152 if email_to
!= None:
1154 if "edward-" + lang
in email_to
:
1158 lang_mod_name
= "lang." + re
.sub('-', '_', use_lang
)
1159 lang_module
= importlib
.import_module(lang_mod_name
)
1161 reply_from
= "edward-" + use_lang
+ "@" + hostname
1163 return lang_module
, reply_from
1166 def generate_encrypted_mime (plaintext
, email_to
, email_subject
, encrypt_to_key
,
1168 """This function creates the mime email reply. It can encrypt the email.
1170 If the encrypt_key is included, then the email is encrypted and signed.
1171 Otherwise it is unencrypted.
1174 plaintext: the plaintext body of the message to create.
1175 email_to: the email address to reply to
1176 email_subject: the subject to use in reply
1177 encrypt_to_key: the key object to use for encrypting the email. (or
1179 gpgme_ctx: the gpgme context
1182 A string version of the mime message, possibly encrypted and signed.
1185 if (encrypt_to_key
!= None):
1187 plaintext_mime
= MIMEText(plaintext
)
1188 plaintext_mime
.set_charset('utf-8')
1190 encrypted_text
= encrypt_sign_message(plaintext_mime
.as_string(),
1194 control_mime
= MIMEApplication("Version: 1",
1195 _subtype
='pgp-encrypted',
1196 _encoder
=email
.encoders
.encode_7or8bit
)
1197 control_mime
['Content-Description'] = 'PGP/MIME version identification'
1198 control_mime
.set_charset('us-ascii')
1200 encoded_mime
= MIMEApplication(encrypted_text
,
1201 _subtype
='octet-stream; name="encrypted.asc"',
1202 _encoder
=email
.encoders
.encode_7or8bit
)
1203 encoded_mime
['Content-Description'] = 'OpenPGP encrypted message'
1204 encoded_mime
['Content-Disposition'] = 'inline; filename="encrypted.asc"'
1205 encoded_mime
.set_charset('us-ascii')
1207 message_mime
= MIMEMultipart(_subtype
="encrypted", protocol
="application/pgp-encrypted")
1208 message_mime
.attach(control_mime
)
1209 message_mime
.attach(encoded_mime
)
1210 message_mime
['Content-Disposition'] = 'inline'
1213 message_mime
= MIMEText(plaintext
)
1214 message_mime
.set_charset('utf-8')
1216 message_mime
['To'] = email_to
1217 message_mime
['Subject'] = email_subject
1219 reply
= message_mime
.as_string()
1224 def send_reply(email_txt
, subject
, reply_to
, reply_from
):
1226 email_bytes
= email_txt
.encode('ascii')
1228 p
= subprocess
.Popen(["/usr/sbin/sendmail", "-f", reply_from
, "-F", "Edward, GPG Bot", "-i", reply_to
], stdin
=subprocess
.PIPE
)
1230 (stdout
, stderr
) = p
.communicate(email_bytes
)
1233 debug("sendmail stdout: " + str(stdout
))
1235 error("sendmail stderr: " + str(stderr
))
1238 def email_quote_text (text
):
1239 """Quotes input text by inserting "> "s
1241 This is useful for quoting a text for the reply message. It inserts "> "
1242 strings at the beginning of lines.
1245 text: plain text to quote
1251 quoted_message
= re
.sub(r
'^', r
'> ', text
, flags
=re
.MULTILINE
)
1253 return quoted_message
1256 def encrypt_sign_message (plaintext
, encrypt_to_key
, gpgme_ctx
):
1257 """Encrypts and signs plaintext
1259 This encrypts and signs a message.
1262 plaintext: text to sign and ecrypt
1263 encrypt_to_key: the key object to encrypt to
1264 gpgme_ctx: the gpgme context
1267 An encrypted and signed string of text
1270 # the plaintext should be mime encoded in an ascii-compatible form
1271 plaintext_bytes
= io
.BytesIO(plaintext
.encode('ascii'))
1272 encrypted_bytes
= io
.BytesIO()
1274 gpgme_ctx
.encrypt_sign([encrypt_to_key
], gpgme
.ENCRYPT_ALWAYS_TRUST
,
1275 plaintext_bytes
, encrypted_bytes
)
1277 encrypted_txt
= encrypted_bytes
.getvalue().decode('ascii')
1278 return encrypted_txt
1281 def error (error_msg
):
1282 """Write an error message to stdout
1284 The error message includes the program name.
1287 error_msg: the message to print
1293 An error message is printed to stdout
1296 sys
.stderr
.write(progname
+ ": " + str(error_msg
) + "\n")
1299 def debug (debug_msg
):
1300 """Writes a debug message to stdout if debug == True
1302 If the debug option is set in edward_config.py, then the passed message
1303 gets printed to stdout.
1306 debug_msg: the message to print to stdout
1312 A debug message is printed to stdout
1315 if edward_config
.debug
== True:
1320 """Sets the progname variable and processes optional argument
1322 If there are more than two arguments then edward complains and quits. An
1323 single "-p" argument sets the print_reply_only option, which makes edward
1324 print email replies instead of mailing them.
1330 True if edward should print arguments instead of mailing them,
1331 otherwise it returns False.
1334 Exits with error 1 if there are more than two arguments, otherwise
1335 returns the print_reply_only option.
1339 progname
= sys
.argv
[0]
1341 print_reply_only
= False
1343 if len(sys
.argv
) > 2:
1344 print(progname
+ " usage: " + progname
+ " [-p]\n\n" \
1345 + " -p print reply message to stdout, do not mail it\n", \
1349 elif (len(sys
.argv
) == 2) and (sys
.argv
[1] == "-p"):
1350 print_reply_only
= True
1352 return print_reply_only
1355 if __name__
== "__main__":
1356 """Executes main if this file is not loaded interactively"""