d4548ce101f3c406e5524e62ba15899193551e8f
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", "es", "fr", "it", "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 debug('decrypt success')
917 reply_plain
+= replyinfo_obj
.replies
['success_decrypt']
918 reply_plain
+= "\n\n"
920 if (replyinfo_obj
.sig_success
== True) and (replyinfo_obj
.have_reply_key
== True):
921 debug('message quoted')
922 quoted_text
= email_quote_text(replyinfo_obj
.msg_to_quote
)
923 reply_plain
+= quoted_text
924 reply_plain
+= "\n\n"
927 debug('decrypt failure')
928 reply_plain
+= replyinfo_obj
.replies
['failed_decrypt']
929 reply_plain
+= "\n\n"
931 if replyinfo_obj
.sig_success
== True:
932 debug('signature success')
933 reply_plain
+= replyinfo_obj
.replies
['sig_success']
934 reply_plain
+= "\n\n"
937 debug('signature failure')
938 reply_plain
+= replyinfo_obj
.replies
['sig_failure']
939 reply_plain
+= "\n\n"
941 if (replyinfo_obj
.pubkey_success
== True):
942 debug('public key received')
943 reply_plain
+= replyinfo_obj
.replies
['public_key_received']
944 reply_plain
+= "\n\n"
946 elif (replyinfo_obj
.sigkey_missing
== True):
947 debug('no public key')
948 reply_plain
+= replyinfo_obj
.replies
['no_public_key']
949 reply_plain
+= "\n\n"
952 reply_plain
+= replyinfo_obj
.replies
['signature']
953 reply_plain
+= "\n\n"
958 def add_gpg_key (key_block
, gpgme_ctx
):
959 """Adds a GPG pubkey to the local keystore
961 This adds keys received through email into the key store so they can be
965 key_block: the string form of the ascii-armored public key block
966 gpgme_ctx: the gpgme context
969 the fingerprint(s) of the imported key(s)
972 fp
= io
.BytesIO(key_block
.encode('ascii'))
975 result
= gpgme_ctx
.import_(fp
)
976 imports
= result
.imports
977 except gpgme
.GpgmeError
:
980 key_fingerprints
= []
983 for import_
in imports
:
984 fingerprint
= import_
[0]
985 key_fingerprints
+= [fingerprint
]
987 debug("added gpg key: " + fingerprint
)
989 return key_fingerprints
992 def verify_sig_message (msg_block
, gpgme_ctx
):
993 """Verifies the signature of a signed, ascii-armored block of text.
995 It encodes the string into ascii, since binary GPG files are currently
996 unsupported, and alternative, the ascii-armored format is encodable into
1000 msg_block: a GPG Message block in string form. It may be encrypted or
1001 not. If it is encrypted, it will return empty results.
1002 gpgme_ctx: the gpgme context
1005 A tuple containing the plaintext of the signed part, the list of
1006 fingerprints of keys signing the data, and a boolean marking whether
1007 edward is missing all public keys for validating any of the signatures.
1008 If verification failed, perhaps because the message was also encrypted,
1009 then empty results are returned.
1012 block_b
= io
.BytesIO(msg_block
.encode('ascii'))
1013 plain_b
= io
.BytesIO()
1016 sigs
= gpgme_ctx
.verify(block_b
, None, plain_b
)
1017 except gpgme
.GpgmeError
:
1018 return ("",[],False)
1020 plaintext
= plain_b
.getvalue().decode('utf-8')
1022 sigkey_missing
= False
1025 if (sig
.summary
== 0) or (sig
.summary
& gpgme
.SIGSUM_VALID
!= 0) or (sig
.summary
& gpgme
.SIGSUM_GREEN
!= 0):
1026 fingerprints
+= [sig
.fpr
]
1027 sigkey_missing
= False
1030 if (sig
.summary
& gpgme
.SIGSUM_KEY_MISSING
!= 0):
1031 sigkey_missing
= True
1033 return (plaintext
, fingerprints
, sigkey_missing
)
1036 def verify_detached_signature (detached_sig
, plaintext_bytes
, gpgme_ctx
):
1037 """Verifies the signature of a detached signature.
1039 This requires the signature part and the signed part as separate arguments.
1042 detached_sig: the signature part of the detached signature
1043 plaintext_bytes: the byte form of the message being signed.
1044 gpgme_ctx: the gpgme context
1047 A tuple containging a list of signing fingerprints if the signature
1048 verification was sucessful, and a boolean marking whether edward is
1049 missing all public keys for validating any of the signatures.
1050 Otherwise, a tuple containing an empty list and True are returned.
1053 detached_sig_fp
= io
.BytesIO(detached_sig
.encode('ascii'))
1054 plaintext_fp
= io
.BytesIO(plaintext_bytes
)
1057 result
= gpgme_ctx
.verify(detached_sig_fp
, plaintext_fp
, None)
1058 except gpgme
.GpgmeError
:
1061 sigkey_missing
= False
1062 sig_fingerprints
= []
1064 if (res_
.summary
== 0) or (res_
.summary
& gpgme
.SIGSUM_VALID
!= 0) or (res_
.summary
& gpgme
.SIGSUM_GREEN
!= 0):
1065 sig_fingerprints
+= [res_
.fpr
]
1066 sigkey_missing
= False
1069 if (res_
.summary
& gpgme
.SIGSUM_KEY_MISSING
!= 0):
1070 sigkey_missing
= True
1072 return (sig_fingerprints
, sigkey_missing
)
1075 def decrypt_block (msg_block
, gpgme_ctx
):
1076 """Decrypts a block of GPG text and verifies any included sigatures.
1078 Some encypted messages have embeded signatures, so those are verified too.
1081 msg_block: the encrypted(/signed) text
1082 gpgme_ctx: the gpgme context
1085 A tuple containing plaintext, signatures (if the decryption and
1086 signature verification were successful, respectively), and a boolean
1087 marking whether edward is missing all public keys for validating any of
1091 block_b
= io
.BytesIO(msg_block
.encode('ascii'))
1092 plain_b
= io
.BytesIO()
1095 sigs
= gpgme_ctx
.decrypt_verify(block_b
, plain_b
)
1096 except gpgme
.GpgmeError
:
1097 return ("",[],False)
1099 plaintext
= plain_b
.getvalue().decode('utf-8')
1101 sigkey_missing
= False
1104 if (sig
.summary
== 0) or (sig
.summary
& gpgme
.SIGSUM_VALID
!= 0) or (sig
.summary
& gpgme
.SIGSUM_GREEN
!= 0):
1105 fingerprints
+= [sig
.fpr
]
1106 sigkey_missing
= False
1109 if (sig
.summary
& gpgme
.SIGSUM_KEY_MISSING
!= 0):
1110 sigkey_missing
= True
1112 return (plaintext
, fingerprints
, sigkey_missing
)
1115 def email_to_from_subject (email_text
):
1116 """Returns the values of the email's To:, From: and Subject: fields
1118 Returns this information from an email.
1121 email_text: the string form of the email
1124 the email To:, From:, and Subject: fields as strings
1127 email_struct
= email
.parser
.Parser().parsestr(email_text
)
1129 email_to
= email_struct
['To']
1130 email_from
= email_struct
['From']
1131 email_subject
= email_struct
['Subject']
1133 return email_to
, email_from
, email_subject
1136 def import_lang_pick_address(email_to
, hostname
):
1137 """Imports language file for i18n support; makes reply from address
1139 The language imported depends on the To: address of the email received by
1140 edward. an -en ending implies the English language, whereas a -ja ending
1141 implies Japanese. The list of supported languages is listed in the 'langs'
1142 list at the beginning of the program. This function also chooses the
1143 language-dependent address which can be used as the From address in the
1147 email_to: the string containing the email address that the mail was
1149 hostname: the hostname part of the reply email's from address
1152 the reference to the imported language module. The only variable in
1153 this file is the 'replies' dictionary.
1159 if email_to
!= None:
1161 if "edward-" + lang
in email_to
:
1165 lang_mod_name
= "lang." + re
.sub('-', '_', use_lang
)
1166 lang_module
= importlib
.import_module(lang_mod_name
)
1168 reply_from
= "edward-" + use_lang
+ "@" + hostname
1170 return lang_module
, reply_from
1173 def generate_encrypted_mime (plaintext
, email_to
, email_subject
, encrypt_to_key
,
1175 """This function creates the mime email reply. It can encrypt the email.
1177 If the encrypt_key is included, then the email is encrypted and signed.
1178 Otherwise it is unencrypted.
1181 plaintext: the plaintext body of the message to create.
1182 email_to: the email address to reply to
1183 email_subject: the subject to use in reply
1184 encrypt_to_key: the key object to use for encrypting the email. (or
1186 gpgme_ctx: the gpgme context
1189 A string version of the mime message, possibly encrypted and signed.
1192 if (encrypt_to_key
!= None):
1194 plaintext_mime
= MIMEText(plaintext
)
1195 plaintext_mime
.set_charset('utf-8')
1197 encrypted_text
= encrypt_sign_message(plaintext_mime
.as_string(),
1201 control_mime
= MIMEApplication("Version: 1",
1202 _subtype
='pgp-encrypted',
1203 _encoder
=email
.encoders
.encode_7or8bit
)
1204 control_mime
['Content-Description'] = 'PGP/MIME version identification'
1205 control_mime
.set_charset('us-ascii')
1207 encoded_mime
= MIMEApplication(encrypted_text
,
1208 _subtype
='octet-stream; name="encrypted.asc"',
1209 _encoder
=email
.encoders
.encode_7or8bit
)
1210 encoded_mime
['Content-Description'] = 'OpenPGP encrypted message'
1211 encoded_mime
['Content-Disposition'] = 'inline; filename="encrypted.asc"'
1212 encoded_mime
.set_charset('us-ascii')
1214 message_mime
= MIMEMultipart(_subtype
="encrypted", protocol
="application/pgp-encrypted")
1215 message_mime
.attach(control_mime
)
1216 message_mime
.attach(encoded_mime
)
1217 message_mime
['Content-Disposition'] = 'inline'
1220 message_mime
= MIMEText(plaintext
)
1221 message_mime
.set_charset('utf-8')
1223 message_mime
['To'] = email_to
1224 message_mime
['Subject'] = email_subject
1226 reply
= message_mime
.as_string()
1231 def send_reply(email_txt
, subject
, reply_to
, reply_from
):
1233 email_bytes
= email_txt
.encode('ascii')
1235 p
= subprocess
.Popen(["/usr/sbin/sendmail", "-f", reply_from
, "-F", "Edward, GPG Bot", "-i", reply_to
], stdin
=subprocess
.PIPE
)
1237 (stdout
, stderr
) = p
.communicate(email_bytes
)
1240 debug("sendmail stdout: " + str(stdout
))
1242 error("sendmail stderr: " + str(stderr
))
1245 def email_quote_text (text
):
1246 """Quotes input text by inserting "> "s
1248 This is useful for quoting a text for the reply message. It inserts "> "
1249 strings at the beginning of lines.
1252 text: plain text to quote
1258 quoted_message
= re
.sub(r
'^', r
'> ', text
, flags
=re
.MULTILINE
)
1260 return quoted_message
1263 def encrypt_sign_message (plaintext
, encrypt_to_key
, gpgme_ctx
):
1264 """Encrypts and signs plaintext
1266 This encrypts and signs a message.
1269 plaintext: text to sign and ecrypt
1270 encrypt_to_key: the key object to encrypt to
1271 gpgme_ctx: the gpgme context
1274 An encrypted and signed string of text
1277 # the plaintext should be mime encoded in an ascii-compatible form
1278 plaintext_bytes
= io
.BytesIO(plaintext
.encode('ascii'))
1279 encrypted_bytes
= io
.BytesIO()
1281 gpgme_ctx
.encrypt_sign([encrypt_to_key
], gpgme
.ENCRYPT_ALWAYS_TRUST
,
1282 plaintext_bytes
, encrypted_bytes
)
1284 encrypted_txt
= encrypted_bytes
.getvalue().decode('ascii')
1285 return encrypted_txt
1288 def error (error_msg
):
1289 """Write an error message to stdout
1291 The error message includes the program name.
1294 error_msg: the message to print
1300 An error message is printed to stdout
1303 sys
.stderr
.write(progname
+ ": " + str(error_msg
) + "\n")
1306 def debug (debug_msg
):
1307 """Writes a debug message to stdout if debug == True
1309 If the debug option is set in edward_config.py, then the passed message
1310 gets printed to stdout.
1313 debug_msg: the message to print to stdout
1319 A debug message is printed to stdout
1322 if edward_config
.debug
== True:
1327 """Sets the progname variable and processes optional argument
1329 If there are more than two arguments then edward complains and quits. An
1330 single "-p" argument sets the print_reply_only option, which makes edward
1331 print email replies instead of mailing them.
1337 True if edward should print arguments instead of mailing them,
1338 otherwise it returns False.
1341 Exits with error 1 if there are more than two arguments, otherwise
1342 returns the print_reply_only option.
1346 progname
= sys
.argv
[0]
1348 print_reply_only
= False
1350 if len(sys
.argv
) > 2:
1351 print(progname
+ " usage: " + progname
+ " [-p]\n\n" \
1352 + " -p print reply message to stdout, do not mail it\n", \
1356 elif (len(sys
.argv
) == 2) and (sys
.argv
[1] == "-p"):
1357 print_reply_only
= True
1359 return print_reply_only
1362 if __name__
== "__main__":
1363 """Executes main if this file is not loaded interactively"""