lisp/gnus/mml2015.el

   1 ;;; mml2015.el --- MIME Security with Pretty Good Privacy (PGP)
   2
   3 ;; Copyright (C) 2000-2012 Free Software Foundation, Inc.
   4
   5 ;; Author: Shenghuo Zhu <zsh@cs.rochester.edu>
   6 ;; Keywords: PGP MIME MML
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software: you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation, either version 3 of the License, or
  13 ;; (at your option) any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  22
  23 ;;; Commentary:
  24
  25 ;; RFC 2015 is updated by RFC 3156, this file should be compatible
  26 ;; with both.
  27
  28 ;;; Code:
  29
  30 (eval-and-compile
  31   ;; For Emacs <22.2 and XEmacs.
  32   (unless (fboundp 'declare-function) (defmacro declare-function (&rest r)))
  33
  34   (if (locate-library "password-cache")
  35       (require 'password-cache)
  36     (require 'password)))
  37
  38 (eval-when-compile (require 'cl))
  39 (require 'mm-decode)
  40 (require 'mm-util)
  41 (require 'mml)
  42 (require 'mml-sec)
  43
  44 (defvar mc-pgp-always-sign)
  45
  46 (declare-function epg-check-configuration "ext:epg-config"
  47                   (config &optional minimum-version))
  48 (declare-function epg-configuration "ext:epg-config" ())
  49
  50 (defvar mml2015-use (or
  51                      (condition-case nil
  52                          (progn
  53                            (require 'epg-config)
  54                            (epg-check-configuration (epg-configuration))
  55                            'epg)
  56                        (error))
  57                      (progn
  58                        (let ((abs-file (locate-library "pgg")))
  59                          ;; Don't load PGG if it is marked as obsolete
  60                          ;; (Emacs 24).
  61                          (when (and abs-file
  62                                     (not (string-match "/obsolete/[^/]*\\'"
  63                                                        abs-file)))
  64                            (ignore-errors (require 'pgg))
  65                            (and (fboundp 'pgg-sign-region)
  66                                 'pgg))))
  67                      (progn (ignore-errors
  68                               (load "mc-toplev"))
  69                             (and (fboundp 'mc-encrypt-generic)
  70                                  (fboundp 'mc-sign-generic)
  71                                  (fboundp 'mc-cleanup-recipient-headers)
  72                                  'mailcrypt)))
  73   "The package used for PGP/MIME.
  74 Valid packages include `epg', `pgg' and `mailcrypt'.")
  75
  76 ;; Something is not RFC2015.
  77 (defvar mml2015-function-alist
  78   '((mailcrypt mml2015-mailcrypt-sign
  79                mml2015-mailcrypt-encrypt
  80                mml2015-mailcrypt-verify
  81                mml2015-mailcrypt-decrypt
  82                mml2015-mailcrypt-clear-verify
  83                mml2015-mailcrypt-clear-decrypt)
  84     (pgg mml2015-pgg-sign
  85          mml2015-pgg-encrypt
  86          mml2015-pgg-verify
  87          mml2015-pgg-decrypt
  88          mml2015-pgg-clear-verify
  89          mml2015-pgg-clear-decrypt)
  90     (epg mml2015-epg-sign
  91          mml2015-epg-encrypt
  92          mml2015-epg-verify
  93          mml2015-epg-decrypt
  94          mml2015-epg-clear-verify
  95          mml2015-epg-clear-decrypt))
  96   "Alist of PGP/MIME functions.")
  97
  98 (defvar mml2015-result-buffer nil)
  99
 100 (defcustom mml2015-unabbrev-trust-alist
 101   '(("TRUST_UNDEFINED" . nil)
 102     ("TRUST_NEVER"     . nil)
 103     ("TRUST_MARGINAL"  . t)
 104     ("TRUST_FULLY"     . t)
 105     ("TRUST_ULTIMATE"  . t))
 106   "Map GnuPG trust output values to a boolean saying if you trust the key."
 107   :version "22.1"
 108   :group 'mime-security
 109   :type '(repeat (cons (regexp :tag "GnuPG output regexp")
 110                        (boolean :tag "Trust key"))))
 111
 112 (defcustom mml2015-cache-passphrase mml-secure-cache-passphrase
 113   "If t, cache passphrase."
 114   :group 'mime-security
 115   :type 'boolean)
 116
 117 (defcustom mml2015-passphrase-cache-expiry mml-secure-passphrase-cache-expiry
 118   "How many seconds the passphrase is cached.
 119 Whether the passphrase is cached at all is controlled by
 120 `mml2015-cache-passphrase'."
 121   :group 'mime-security
 122   :type 'integer)
 123
 124 (defcustom mml2015-signers nil
 125   "A list of your own key ID(s) which will be used to sign a message.
 126 If set, it overrides the setting of `mml2015-sign-with-sender'."
 127   :group 'mime-security
 128   :type '(repeat (string :tag "Key ID")))
 129
 130 (defcustom mml2015-sign-with-sender nil
 131   "If t, use message sender so find a key to sign with."
 132   :group 'mime-security
 133   :type 'boolean
 134   :version "24.1")
 135
 136 (defcustom mml2015-encrypt-to-self nil
 137   "If t, add your own key ID to recipient list when encryption."
 138   :group 'mime-security
 139   :type 'boolean)
 140
 141 (defcustom mml2015-always-trust t
 142   "If t, GnuPG skip key validation on encryption."
 143   :group 'mime-security
 144   :type 'boolean)
 145
 146 ;; Extract plaintext from cleartext signature.  IMO, this kind of task
 147 ;; should be done by GnuPG rather than Elisp, but older PGP backends
 148 ;; (such as Mailcrypt, and PGG) discard the output from GnuPG.
 149 (defun mml2015-extract-cleartext-signature ()
 150   ;; Daiki Ueno in
 151   ;; <54a15d860801080142l70b95d7dkac4bf51a86196011@mail.gmail.com>: ``I still
 152   ;; believe that the right way is to use the plaintext output from GnuPG as
 153   ;; it is, and mml2015-extract-cleartext-signature is just a kludge for
 154   ;; misdesigned libraries like PGG, which have no ability to do that.  So, I
 155   ;; think it should not have descriptive documentation.''
 156   ;;
 157   ;; This function doesn't handle NotDashEscaped correctly.  EasyPG handles it
 158   ;; correctly.
 159   ;; http://thread.gmane.org/gmane.emacs.gnus.general/66062/focus=66082
 160   ;; http://thread.gmane.org/gmane.emacs.gnus.general/65087/focus=65109
 161   (goto-char (point-min))
 162   (forward-line)
 163   ;; We need to be careful not to strip beyond the armor headers.
 164   ;; Previously, an attacker could replace the text inside our
 165   ;; markup with trailing garbage by injecting whitespace into the
 166   ;; message.
 167   (while (looking-at "Hash:")           ; The only header allowed in cleartext
 168     (forward-line))                     ; signatures according to RFC2440.
 169   (when (looking-at "[\t ]*$")
 170     (forward-line))
 171   (delete-region (point-min) (point))
 172   (if (re-search-forward "^-----BEGIN PGP SIGNATURE-----" nil t)
 173       (delete-region (match-beginning 0) (point-max)))
 174   (goto-char (point-min))
 175   (while (re-search-forward "^- " nil t)
 176     (replace-match "" t t)
 177     (forward-line 1)))
 178
 179 ;;; mailcrypt wrapper
 180
 181 (autoload 'mailcrypt-decrypt "mailcrypt")
 182 (autoload 'mailcrypt-verify "mailcrypt")
 183 (autoload 'mc-pgp-always-sign "mailcrypt")
 184 (autoload 'mc-encrypt-generic "mc-toplev")
 185 (autoload 'mc-cleanup-recipient-headers "mc-toplev")
 186 (autoload 'mc-sign-generic "mc-toplev")
 187
 188 (defvar mml2015-decrypt-function 'mailcrypt-decrypt)
 189 (defvar mml2015-verify-function 'mailcrypt-verify)
 190
 191 (defun mml2015-format-error (err)
 192   (if (stringp (cadr err))
 193       (cadr err)
 194     (format "%S" (cdr err))))
 195
 196 (defun mml2015-mailcrypt-decrypt (handle ctl)
 197   (catch 'error
 198     (let (child handles result)
 199       (unless (setq child (mm-find-part-by-type
 200                            (cdr handle)
 201                            "application/octet-stream" nil t))
 202         (mm-set-handle-multipart-parameter
 203          mm-security-handle 'gnus-info "Corrupted")
 204         (throw 'error handle))
 205       (with-temp-buffer
 206         (mm-insert-part child)
 207         (setq result
 208               (condition-case err
 209                   (funcall mml2015-decrypt-function)
 210                 (error
 211                  (mm-set-handle-multipart-parameter
 212                   mm-security-handle 'gnus-details (mml2015-format-error err))
 213                  nil)
 214                 (quit
 215                  (mm-set-handle-multipart-parameter
 216                   mm-security-handle 'gnus-details "Quit.")
 217                  nil)))
 218         (unless (car result)
 219           (mm-set-handle-multipart-parameter
 220            mm-security-handle 'gnus-info "Failed")
 221           (throw 'error handle))
 222         (setq handles (mm-dissect-buffer t)))
 223       (mm-destroy-parts handle)
 224       (mm-set-handle-multipart-parameter
 225        mm-security-handle 'gnus-info
 226        (concat "OK"
 227                (let ((sig (with-current-buffer mml2015-result-buffer
 228                             (mml2015-gpg-extract-signature-details))))
 229                  (concat ", Signer: " sig))))
 230       (if (listp (car handles))
 231           handles
 232         (list handles)))))
 233
 234 (defun mml2015-gpg-pretty-print-fpr (fingerprint)
 235   (let* ((result "")
 236          (fpr-length (string-width fingerprint))
 237          (n-slice 0)
 238          slice)
 239     (setq fingerprint (string-to-list fingerprint))
 240     (while fingerprint
 241       (setq fpr-length (- fpr-length 4))
 242       (setq slice (butlast fingerprint fpr-length))
 243       (setq fingerprint (nthcdr 4 fingerprint))
 244       (setq n-slice (1+ n-slice))
 245       (setq result
 246             (concat
 247              result
 248              (case n-slice
 249                (1  slice)
 250                (otherwise (concat " " slice))))))
 251     result))
 252
 253 (defun mml2015-gpg-extract-signature-details ()
 254   (goto-char (point-min))
 255   (let* ((expired (re-search-forward
 256                    "^\\[GNUPG:\\] SIGEXPIRED$"
 257                    nil t))
 258          (signer (and (re-search-forward
 259                        "^\\[GNUPG:\\] GOODSIG \\([0-9A-Za-z]*\\) \\(.*\\)$"
 260                        nil t)
 261                       (cons (match-string 1) (match-string 2))))
 262          (fprint (and (re-search-forward
 263                        "^\\[GNUPG:\\] VALIDSIG \\([0-9a-zA-Z]*\\) "
 264                        nil t)
 265                       (match-string 1)))
 266          (trust  (and (re-search-forward
 267                        "^\\[GNUPG:\\] \\(TRUST_.*\\)$"
 268                        nil t)
 269                       (match-string 1)))
 270          (trust-good-enough-p
 271           (cdr (assoc trust mml2015-unabbrev-trust-alist))))
 272     (cond ((and signer fprint)
 273            (concat (cdr signer)
 274                    (unless trust-good-enough-p
 275                      (concat "\nUntrusted, Fingerprint: "
 276                              (mml2015-gpg-pretty-print-fpr fprint)))
 277                    (when expired
 278                      (format "\nWARNING: Signature from expired key (%s)"
 279                              (car signer)))))
 280           ((re-search-forward
 281             "^\\(gpg: \\)?Good signature from \"\\(.*\\)\"$" nil t)
 282            (match-string 2))
 283           (t
 284            "From unknown user"))))
 285
 286 (defun mml2015-mailcrypt-clear-decrypt ()
 287   (let (result)
 288     (setq result
 289           (condition-case err
 290               (funcall mml2015-decrypt-function)
 291             (error
 292              (mm-set-handle-multipart-parameter
 293               mm-security-handle 'gnus-details (mml2015-format-error err))
 294              nil)
 295             (quit
 296              (mm-set-handle-multipart-parameter
 297               mm-security-handle 'gnus-details "Quit.")
 298              nil)))
 299     (if (car result)
 300         (mm-set-handle-multipart-parameter
 301          mm-security-handle 'gnus-info "OK")
 302       (mm-set-handle-multipart-parameter
 303        mm-security-handle 'gnus-info "Failed"))))
 304
 305 (defun mml2015-fix-micalg (alg)
 306   (and alg
 307        ;; Mutt/1.2.5i has seen sending micalg=php-sha1
 308        (upcase (if (string-match "^p[gh]p-" alg)
 309                    (substring alg (match-end 0))
 310                  alg))))
 311
 312 (defun mml2015-mailcrypt-verify (handle ctl)
 313   (catch 'error
 314     (let (part)
 315       (unless (setq part (mm-find-raw-part-by-type
 316                           ctl (or (mm-handle-multipart-ctl-parameter
 317                                    ctl 'protocol)
 318                                   "application/pgp-signature")
 319                           t))
 320         (mm-set-handle-multipart-parameter
 321          mm-security-handle 'gnus-info "Corrupted")
 322         (throw 'error handle))
 323       (with-temp-buffer
 324         (insert "-----BEGIN PGP SIGNED MESSAGE-----\n")
 325         (insert (format "Hash: %s\n\n"
 326                         (or (mml2015-fix-micalg
 327                              (mm-handle-multipart-ctl-parameter
 328                               ctl 'micalg))
 329                             "SHA1")))
 330         (save-restriction
 331           (narrow-to-region (point) (point))
 332           (insert part "\n")
 333           (goto-char (point-min))
 334           (while (not (eobp))
 335             (if (looking-at "^-")
 336                 (insert "- "))
 337             (forward-line)))
 338         (unless (setq part (mm-find-part-by-type
 339                             (cdr handle) "application/pgp-signature" nil t))
 340           (mm-set-handle-multipart-parameter
 341            mm-security-handle 'gnus-info "Corrupted")
 342           (throw 'error handle))
 343         (save-restriction
 344           (narrow-to-region (point) (point))
 345           (mm-insert-part part)
 346           (goto-char (point-min))
 347           (if (re-search-forward "^-----BEGIN PGP [^-]+-----\r?$" nil t)
 348               (replace-match "-----BEGIN PGP SIGNATURE-----" t t))
 349           (if (re-search-forward "^-----END PGP [^-]+-----\r?$" nil t)
 350               (replace-match "-----END PGP SIGNATURE-----" t t)))
 351         (let ((mc-gpg-debug-buffer (get-buffer-create " *gnus gpg debug*")))
 352           (unless (condition-case err
 353                       (prog1
 354                           (funcall mml2015-verify-function)
 355                         (if (get-buffer " *mailcrypt stderr temp")
 356                             (mm-set-handle-multipart-parameter
 357                              mm-security-handle 'gnus-details
 358                              (with-current-buffer " *mailcrypt stderr temp"
 359                                (buffer-string))))
 360                         (if (get-buffer " *mailcrypt stdout temp")
 361                             (kill-buffer " *mailcrypt stdout temp"))
 362                         (if (get-buffer " *mailcrypt stderr temp")
 363                             (kill-buffer " *mailcrypt stderr temp"))
 364                         (if (get-buffer " *mailcrypt status temp")
 365                             (kill-buffer " *mailcrypt status temp"))
 366                         (if (get-buffer mc-gpg-debug-buffer)
 367                             (kill-buffer mc-gpg-debug-buffer)))
 368                     (error
 369                      (mm-set-handle-multipart-parameter
 370                       mm-security-handle 'gnus-details (mml2015-format-error err))
 371                      nil)
 372                     (quit
 373                      (mm-set-handle-multipart-parameter
 374                       mm-security-handle 'gnus-details "Quit.")
 375                      nil))
 376             (mm-set-handle-multipart-parameter
 377              mm-security-handle 'gnus-info "Failed")
 378             (throw 'error handle))))
 379       (mm-set-handle-multipart-parameter
 380        mm-security-handle 'gnus-info "OK")
 381       handle)))
 382
 383 (defun mml2015-mailcrypt-clear-verify ()
 384   (let ((mc-gpg-debug-buffer (get-buffer-create " *gnus gpg debug*")))
 385     (if (condition-case err
 386             (prog1
 387                 (funcall mml2015-verify-function)
 388               (if (get-buffer " *mailcrypt stderr temp")
 389                   (mm-set-handle-multipart-parameter
 390                    mm-security-handle 'gnus-details
 391                    (with-current-buffer " *mailcrypt stderr temp"
 392                      (buffer-string))))
 393               (if (get-buffer " *mailcrypt stdout temp")
 394                   (kill-buffer " *mailcrypt stdout temp"))
 395               (if (get-buffer " *mailcrypt stderr temp")
 396                   (kill-buffer " *mailcrypt stderr temp"))
 397               (if (get-buffer " *mailcrypt status temp")
 398                   (kill-buffer " *mailcrypt status temp"))
 399               (if (get-buffer mc-gpg-debug-buffer)
 400                   (kill-buffer mc-gpg-debug-buffer)))
 401           (error
 402            (mm-set-handle-multipart-parameter
 403             mm-security-handle 'gnus-details (mml2015-format-error err))
 404            nil)
 405           (quit
 406            (mm-set-handle-multipart-parameter
 407             mm-security-handle 'gnus-details "Quit.")
 408            nil))
 409         (mm-set-handle-multipart-parameter
 410          mm-security-handle 'gnus-info "OK")
 411       (mm-set-handle-multipart-parameter
 412        mm-security-handle 'gnus-info "Failed")))
 413   (mml2015-extract-cleartext-signature))
 414
 415 (defun mml2015-mailcrypt-sign (cont)
 416   (mc-sign-generic (message-options-get 'message-sender)
 417                    nil nil nil nil)
 418   (let ((boundary (mml-compute-boundary cont))
 419         hash point)
 420     (goto-char (point-min))
 421     (unless (re-search-forward "^-----BEGIN PGP SIGNED MESSAGE-----\r?$" nil t)
 422       (error "Cannot find signed begin line"))
 423     (goto-char (match-beginning 0))
 424     (forward-line 1)
 425     (unless (looking-at "Hash:[ \t]*\\([a-zA-Z0-9]+\\)")
 426       (error "Cannot not find PGP hash"))
 427     (setq hash (match-string 1))
 428     (unless (re-search-forward "^$" nil t)
 429       (error "Cannot not find PGP message"))
 430     (forward-line 1)
 431     (delete-region (point-min) (point))
 432     (insert (format "Content-Type: multipart/signed; boundary=\"%s\";\n"
 433                     boundary))
 434     (insert (format "\tmicalg=pgp-%s; protocol=\"application/pgp-signature\"\n"
 435                     (downcase hash)))
 436     (insert (format "\n--%s\n" boundary))
 437     (setq point (point))
 438     (goto-char (point-max))
 439     (unless (re-search-backward "^-----END PGP SIGNATURE-----\r?$" nil t)
 440       (error "Cannot find signature part"))
 441     (replace-match "-----END PGP MESSAGE-----" t t)
 442     (goto-char (match-beginning 0))
 443     (unless (re-search-backward "^-----BEGIN PGP SIGNATURE-----\r?$"
 444                                 nil t)
 445       (error "Cannot find signature part"))
 446     (replace-match "-----BEGIN PGP MESSAGE-----" t t)
 447     (goto-char (match-beginning 0))
 448     (save-restriction
 449       (narrow-to-region point (point))
 450       (goto-char point)
 451       (while (re-search-forward "^- -" nil t)
 452         (replace-match "-" t t))
 453       (goto-char (point-max)))
 454     (insert (format "--%s\n" boundary))
 455     (insert "Content-Type: application/pgp-signature\n\n")
 456     (goto-char (point-max))
 457     (insert (format "--%s--\n" boundary))
 458     (goto-char (point-max))))
 459
 460 ;; We require mm-decode, which requires mm-bodies, which autoloads
 461 ;; message-options-get (!).
 462 (declare-function message-options-set "message" (symbol value))
 463
 464 (defun mml2015-mailcrypt-encrypt (cont &optional sign)
 465   (let ((mc-pgp-always-sign
 466          (or mc-pgp-always-sign
 467              sign
 468              (eq t (or (message-options-get 'message-sign-encrypt)
 469                        (message-options-set
 470                         'message-sign-encrypt
 471                         (or (y-or-n-p "Sign the message? ")
 472                             'not))))
 473              'never)))
 474     (mm-with-unibyte-current-buffer
 475       (mc-encrypt-generic
 476        (or (message-options-get 'message-recipients)
 477            (message-options-set 'message-recipients
 478                               (mc-cleanup-recipient-headers
 479                                (read-string "Recipients: "))))
 480        nil nil nil
 481        (message-options-get 'message-sender))))
 482   (goto-char (point-min))
 483   (unless (looking-at "-----BEGIN PGP MESSAGE-----")
 484     (error "Fail to encrypt the message"))
 485   (let ((boundary (mml-compute-boundary cont)))
 486     (insert (format "Content-Type: multipart/encrypted; boundary=\"%s\";\n"
 487                     boundary))
 488     (insert "\tprotocol=\"application/pgp-encrypted\"\n\n")
 489     (insert (format "--%s\n" boundary))
 490     (insert "Content-Type: application/pgp-encrypted\n\n")
 491     (insert "Version: 1\n\n")
 492     (insert (format "--%s\n" boundary))
 493     (insert "Content-Type: application/octet-stream\n\n")
 494     (goto-char (point-max))
 495     (insert (format "--%s--\n" boundary))
 496     (goto-char (point-max))))
 497
 498 ;;; pgg wrapper
 499
 500 (defvar pgg-default-user-id)
 501 (defvar pgg-errors-buffer)
 502 (defvar pgg-output-buffer)
 503
 504 (autoload 'pgg-decrypt-region "pgg")
 505 (autoload 'pgg-verify-region "pgg")
 506 (autoload 'pgg-sign-region "pgg")
 507 (autoload 'pgg-encrypt-region "pgg")
 508 (autoload 'pgg-parse-armor "pgg-parse")
 509
 510 (defun mml2015-pgg-decrypt (handle ctl)
 511   (catch 'error
 512     (let ((pgg-errors-buffer mml2015-result-buffer)
 513           child handles result decrypt-status)
 514       (unless (setq child (mm-find-part-by-type
 515                            (cdr handle)
 516                            "application/octet-stream" nil t))
 517         (mm-set-handle-multipart-parameter
 518          mm-security-handle 'gnus-info "Corrupted")
 519         (throw 'error handle))
 520       (with-temp-buffer
 521         (mm-insert-part child)
 522         (if (condition-case err
 523                 (prog1
 524                     (pgg-decrypt-region (point-min) (point-max))
 525                   (setq decrypt-status
 526                         (with-current-buffer mml2015-result-buffer
 527                           (buffer-string)))
 528                   (mm-set-handle-multipart-parameter
 529                    mm-security-handle 'gnus-details
 530                    decrypt-status))
 531               (error
 532                (mm-set-handle-multipart-parameter
 533                 mm-security-handle 'gnus-details (mml2015-format-error err))
 534                nil)
 535               (quit
 536                (mm-set-handle-multipart-parameter
 537                 mm-security-handle 'gnus-details "Quit.")
 538                nil))
 539             (with-current-buffer pgg-output-buffer
 540               (goto-char (point-min))
 541               (while (search-forward "\r\n" nil t)
 542                 (replace-match "\n" t t))
 543               (setq handles (mm-dissect-buffer t))
 544               (mm-destroy-parts handle)
 545               (mm-set-handle-multipart-parameter
 546                mm-security-handle 'gnus-info "OK")
 547               (mm-set-handle-multipart-parameter
 548                mm-security-handle 'gnus-details
 549                (concat decrypt-status
 550                        (when (stringp (car handles))
 551                          "\n" (mm-handle-multipart-ctl-parameter
 552                                handles 'gnus-details))))
 553               (if (listp (car handles))
 554                   handles
 555                 (list handles)))
 556           (mm-set-handle-multipart-parameter
 557            mm-security-handle 'gnus-info "Failed")
 558           (throw 'error handle))))))
 559
 560 (defun mml2015-pgg-clear-decrypt ()
 561   (let ((pgg-errors-buffer mml2015-result-buffer))
 562     (if (prog1
 563             (pgg-decrypt-region (point-min) (point-max))
 564           (mm-set-handle-multipart-parameter
 565            mm-security-handle 'gnus-details
 566            (with-current-buffer mml2015-result-buffer
 567              (buffer-string))))
 568         (progn
 569           (erase-buffer)
 570           ;; Treat data which pgg returns as a unibyte string.
 571           (mm-disable-multibyte)
 572           (insert-buffer-substring pgg-output-buffer)
 573           (goto-char (point-min))
 574           (while (search-forward "\r\n" nil t)
 575             (replace-match "\n" t t))
 576           (mm-set-handle-multipart-parameter
 577            mm-security-handle 'gnus-info "OK"))
 578       (mm-set-handle-multipart-parameter
 579        mm-security-handle 'gnus-info "Failed"))))
 580
 581 (defun mml2015-pgg-verify (handle ctl)
 582   (let ((pgg-errors-buffer mml2015-result-buffer)
 583         signature-file part signature)
 584     (if (or (null (setq part (mm-find-raw-part-by-type
 585                               ctl (or (mm-handle-multipart-ctl-parameter
 586                                        ctl 'protocol)
 587                                       "application/pgp-signature")
 588                               t)))
 589             (null (setq signature (mm-find-part-by-type
 590                                    (cdr handle) "application/pgp-signature" nil t))))
 591         (progn
 592           (mm-set-handle-multipart-parameter
 593            mm-security-handle 'gnus-info "Corrupted")
 594           handle)
 595       (with-temp-buffer
 596         (insert part)
 597         ;; Convert <LF> to <CR><LF> in signed text.  If --textmode is
 598         ;; specified when signing, the conversion is not necessary.
 599         (goto-char (point-min))
 600         (end-of-line)
 601         (while (not (eobp))
 602           (unless (eq (char-before) ?\r)
 603             (insert "\r"))
 604           (forward-line)
 605           (end-of-line))
 606         (with-temp-file (setq signature-file (mm-make-temp-file "pgg"))
 607           (mm-insert-part signature))
 608         (if (condition-case err
 609                 (prog1
 610                     (pgg-verify-region (point-min) (point-max)
 611                                        signature-file t)
 612                   (goto-char (point-min))
 613                   (while (search-forward "\r\n" nil t)
 614                     (replace-match "\n" t t))
 615                   (mm-set-handle-multipart-parameter
 616                    mm-security-handle 'gnus-details
 617                    (concat (with-current-buffer pgg-output-buffer
 618                              (buffer-string))
 619                            (with-current-buffer pgg-errors-buffer
 620                              (buffer-string)))))
 621               (error
 622                (mm-set-handle-multipart-parameter
 623                 mm-security-handle 'gnus-details (mml2015-format-error err))
 624                nil)
 625               (quit
 626                (mm-set-handle-multipart-parameter
 627                 mm-security-handle 'gnus-details "Quit.")
 628                nil))
 629             (progn
 630               (delete-file signature-file)
 631               (mm-set-handle-multipart-parameter
 632                mm-security-handle 'gnus-info
 633                (with-current-buffer pgg-errors-buffer
 634                  (mml2015-gpg-extract-signature-details))))
 635           (delete-file signature-file)
 636           (mm-set-handle-multipart-parameter
 637            mm-security-handle 'gnus-info "Failed")))))
 638   handle)
 639
 640 (defun mml2015-pgg-clear-verify ()
 641   (let ((pgg-errors-buffer mml2015-result-buffer)
 642         (text (buffer-string))
 643         (coding-system buffer-file-coding-system))
 644     (if (condition-case err
 645             (prog1
 646                 (mm-with-unibyte-buffer
 647                   (insert (mm-encode-coding-string text coding-system))
 648                   (pgg-verify-region (point-min) (point-max) nil t))
 649               (goto-char (point-min))
 650               (while (search-forward "\r\n" nil t)
 651                 (replace-match "\n" t t))
 652               (mm-set-handle-multipart-parameter
 653                mm-security-handle 'gnus-details
 654                (concat (with-current-buffer pgg-output-buffer
 655                          (buffer-string))
 656                        (with-current-buffer pgg-errors-buffer
 657                          (buffer-string)))))
 658           (error
 659            (mm-set-handle-multipart-parameter
 660             mm-security-handle 'gnus-details (mml2015-format-error err))
 661            nil)
 662           (quit
 663            (mm-set-handle-multipart-parameter
 664             mm-security-handle 'gnus-details "Quit.")
 665            nil))
 666         (mm-set-handle-multipart-parameter
 667          mm-security-handle 'gnus-info
 668          (with-current-buffer pgg-errors-buffer
 669            (mml2015-gpg-extract-signature-details)))
 670       (mm-set-handle-multipart-parameter
 671        mm-security-handle 'gnus-info "Failed")))
 672   (mml2015-extract-cleartext-signature))
 673
 674 (defun mml2015-pgg-sign (cont)
 675   (let ((pgg-errors-buffer mml2015-result-buffer)
 676         (boundary (mml-compute-boundary cont))
 677         (pgg-default-user-id (or (message-options-get 'mml-sender)
 678                                  pgg-default-user-id))
 679         (pgg-text-mode t)
 680         entry)
 681     (unless (pgg-sign-region (point-min) (point-max))
 682       (pop-to-buffer mml2015-result-buffer)
 683       (error "Sign error"))
 684     (goto-char (point-min))
 685     (insert (format "Content-Type: multipart/signed; boundary=\"%s\";\n"
 686                     boundary))
 687     (if (setq entry (assq 2 (pgg-parse-armor
 688                              (with-current-buffer pgg-output-buffer
 689                                (buffer-string)))))
 690         (setq entry (assq 'hash-algorithm (cdr entry))))
 691     (insert (format "\tmicalg=%s; "
 692                     (if (cdr entry)
 693                         (downcase (format "pgp-%s" (cdr entry)))
 694                       "pgp-sha1")))
 695     (insert "protocol=\"application/pgp-signature\"\n")
 696     (insert (format "\n--%s\n" boundary))
 697     (goto-char (point-max))
 698     (insert (format "\n--%s\n" boundary))
 699     (insert "Content-Type: application/pgp-signature\n\n")
 700     (insert-buffer-substring pgg-output-buffer)
 701     (goto-char (point-max))
 702     (insert (format "--%s--\n" boundary))
 703     (goto-char (point-max))))
 704
 705 (defun mml2015-pgg-encrypt (cont &optional sign)
 706   (let ((pgg-errors-buffer mml2015-result-buffer)
 707         (pgg-text-mode t)
 708         (boundary (mml-compute-boundary cont)))
 709     (unless (pgg-encrypt-region (point-min) (point-max)
 710                                 (split-string
 711                                  (or
 712                                   (message-options-get 'message-recipients)
 713                                   (message-options-set 'message-recipients
 714                                                        (read-string "Recipients: ")))
 715                                  "[ \f\t\n\r\v,]+")
 716                                 sign)
 717       (pop-to-buffer mml2015-result-buffer)
 718       (error "Encrypt error"))
 719     (delete-region (point-min) (point-max))
 720     (goto-char (point-min))
 721     (insert (format "Content-Type: multipart/encrypted; boundary=\"%s\";\n"
 722                     boundary))
 723     (insert "\tprotocol=\"application/pgp-encrypted\"\n\n")
 724     (insert (format "--%s\n" boundary))
 725     (insert "Content-Type: application/pgp-encrypted\n\n")
 726     (insert "Version: 1\n\n")
 727     (insert (format "--%s\n" boundary))
 728     (insert "Content-Type: application/octet-stream\n\n")
 729     (insert-buffer-substring pgg-output-buffer)
 730     (goto-char (point-max))
 731     (insert (format "--%s--\n" boundary))
 732     (goto-char (point-max))))
 733
 734 ;;; epg wrapper
 735
 736 (defvar epg-user-id-alist)
 737 (defvar epg-digest-algorithm-alist)
 738 (defvar epg-gpg-program)
 739 (defvar inhibit-redisplay)
 740
 741 (autoload 'epg-make-context "epg")
 742 (autoload 'epg-context-set-armor "epg")
 743 (autoload 'epg-context-set-textmode "epg")
 744 (autoload 'epg-context-set-signers "epg")
 745 (autoload 'epg-context-result-for "epg")
 746 (autoload 'epg-new-signature-digest-algorithm "epg")
 747 (autoload 'epg-list-keys "epg")
 748 (autoload 'epg-decrypt-string "epg")
 749 (autoload 'epg-verify-string "epg")
 750 (autoload 'epg-sign-string "epg")
 751 (autoload 'epg-encrypt-string "epg")
 752 (autoload 'epg-passphrase-callback-function "epg")
 753 (autoload 'epg-context-set-passphrase-callback "epg")
 754 (autoload 'epg-key-sub-key-list "epg")
 755 (autoload 'epg-sub-key-capability "epg")
 756 (autoload 'epg-sub-key-validity "epg")
 757 (autoload 'epg-sub-key-fingerprint "epg")
 758 (autoload 'epg-signature-key-id "epg")
 759 (autoload 'epg-signature-to-string "epg")
 760 (autoload 'epg-configuration "epg-config")
 761 (autoload 'epg-expand-group "epg-config")
 762 (autoload 'epa-select-keys "epa")
 763
 764 (defvar mml2015-epg-secret-key-id-list nil)
 765
 766 (defun mml2015-epg-passphrase-callback (context key-id ignore)
 767   (if (eq key-id 'SYM)
 768       (epg-passphrase-callback-function context key-id nil)
 769     (let* ((password-cache-key-id
 770             (if (eq key-id 'PIN)
 771                 "PIN"
 772                key-id))
 773            entry
 774            (passphrase
 775             (password-read
 776              (if (eq key-id 'PIN)
 777                  "Passphrase for PIN: "
 778                (if (setq entry (assoc key-id epg-user-id-alist))
 779                    (format "Passphrase for %s %s: " key-id (cdr entry))
 780                  (format "Passphrase for %s: " key-id)))
 781              password-cache-key-id)))
 782       (when passphrase
 783         (let ((password-cache-expiry mml2015-passphrase-cache-expiry))
 784           (password-cache-add password-cache-key-id passphrase))
 785         (setq mml2015-epg-secret-key-id-list
 786               (cons password-cache-key-id mml2015-epg-secret-key-id-list))
 787         (copy-sequence passphrase)))))
 788
 789 (defun mml2015-epg-find-usable-key (keys usage)
 790   (catch 'found
 791     (while keys
 792       (let ((pointer (epg-key-sub-key-list (car keys))))
 793         ;; The primary key will be marked as disabled, when the entire
 794         ;; key is disabled (see 12 Field, Format of colon listings, in
 795         ;; gnupg/doc/DETAILS)
 796         (unless (memq 'disabled (epg-sub-key-capability (car pointer)))
 797           (while pointer
 798             (if (and (memq usage (epg-sub-key-capability (car pointer)))
 799                      (not (memq (epg-sub-key-validity (car pointer))
 800                                 '(revoked expired))))
 801                 (throw 'found (car keys)))
 802             (setq pointer (cdr pointer)))))
 803       (setq keys (cdr keys)))))
 804
 805 ;; XXX: since gpg --list-secret-keys does not return validity of each
 806 ;; key, `mml2015-epg-find-usable-key' defined above is not enough for
 807 ;; secret keys.  The function `mml2015-epg-find-usable-secret-key'
 808 ;; below looks at appropriate public keys to check usability.
 809 (defun mml2015-epg-find-usable-secret-key (context name usage)
 810   (let ((secret-keys (epg-list-keys context name t))
 811         secret-key)
 812     (while (and (not secret-key) secret-keys)
 813       (if (mml2015-epg-find-usable-key
 814            (epg-list-keys context (epg-sub-key-fingerprint
 815                                    (car (epg-key-sub-key-list
 816                                          (car secret-keys)))))
 817            usage)
 818           (setq secret-key (car secret-keys)
 819                 secret-keys nil)
 820         (setq secret-keys (cdr secret-keys))))
 821     secret-key))
 822
 823 (defun mml2015-epg-key-image (key-id)
 824   "Return the image of a key, if any"
 825   (let ((filename
 826          (replace-regexp-in-string
 827           "\n" ""
 828           (shell-command-to-string
 829            (format "%s --photo-viewer 'echo %%I >&2' --list-keys %s > /dev/null"
 830                    epg-gpg-program key-id)))))
 831     (when (and (not (string-equal filename ""))
 832                (file-exists-p filename))
 833       (create-image filename))))
 834
 835 (defun mml2015-epg-key-image-to-string (key-id)
 836   "Return a string with the image of a key, if any"
 837   (let* ((result "")
 838          (key-image (mml2015-epg-key-image key-id)))
 839     (when key-image
 840       (setq result "  ")
 841       (put-text-property 1 2 'display key-image result))
 842     result))
 843
 844 (defun mml2015-epg-signature-to-string (signature)
 845   (concat (epg-signature-to-string signature)
 846           (mml2015-epg-key-image-to-string (epg-signature-key-id signature))))
 847
 848 (defun mml2015-epg-verify-result-to-string (verify-result)
 849   (mapconcat #'mml2015-epg-signature-to-string verify-result "\n"))
 850
 851 (defun mml2015-epg-decrypt (handle ctl)
 852   (catch 'error
 853     (let ((inhibit-redisplay t)
 854           context plain child handles result decrypt-status)
 855       (unless (setq child (mm-find-part-by-type
 856                            (cdr handle)
 857                            "application/octet-stream" nil t))
 858         (mm-set-handle-multipart-parameter
 859          mm-security-handle 'gnus-info "Corrupted")
 860         (throw 'error handle))
 861       (setq context (epg-make-context))
 862       (if mml2015-cache-passphrase
 863           (epg-context-set-passphrase-callback
 864            context
 865            #'mml2015-epg-passphrase-callback))
 866       (condition-case error
 867           (setq plain (epg-decrypt-string context (mm-get-part child))
 868                 mml2015-epg-secret-key-id-list nil)
 869         (error
 870          (while mml2015-epg-secret-key-id-list
 871            (password-cache-remove (car mml2015-epg-secret-key-id-list))
 872            (setq mml2015-epg-secret-key-id-list
 873                  (cdr mml2015-epg-secret-key-id-list)))
 874          (mm-set-handle-multipart-parameter
 875           mm-security-handle 'gnus-info "Failed")
 876          (if (eq (car error) 'quit)
 877              (mm-set-handle-multipart-parameter
 878               mm-security-handle 'gnus-details "Quit.")
 879            (mm-set-handle-multipart-parameter
 880             mm-security-handle 'gnus-details (mml2015-format-error error)))
 881          (throw 'error handle)))
 882       (with-temp-buffer
 883         (insert plain)
 884         (goto-char (point-min))
 885         (while (search-forward "\r\n" nil t)
 886           (replace-match "\n" t t))
 887         (setq handles (mm-dissect-buffer t))
 888         (mm-destroy-parts handle)
 889         (if (epg-context-result-for context 'verify)
 890             (mm-set-handle-multipart-parameter
 891              mm-security-handle 'gnus-info
 892              (concat "OK\n"
 893                      (mml2015-epg-verify-result-to-string
 894                       (epg-context-result-for context 'verify))))
 895           (mm-set-handle-multipart-parameter
 896            mm-security-handle 'gnus-info "OK"))
 897         (if (stringp (car handles))
 898             (mm-set-handle-multipart-parameter
 899              mm-security-handle 'gnus-details
 900              (mm-handle-multipart-ctl-parameter handles 'gnus-details))))
 901         (if (listp (car handles))
 902             handles
 903           (list handles)))))
 904
 905 (defun mml2015-epg-clear-decrypt ()
 906   (let ((inhibit-redisplay t)
 907         (context (epg-make-context))
 908         plain)
 909     (if mml2015-cache-passphrase
 910         (epg-context-set-passphrase-callback
 911          context
 912          #'mml2015-epg-passphrase-callback))
 913     (condition-case error
 914         (setq plain (epg-decrypt-string context (buffer-string))
 915               mml2015-epg-secret-key-id-list nil)
 916       (error
 917        (while mml2015-epg-secret-key-id-list
 918          (password-cache-remove (car mml2015-epg-secret-key-id-list))
 919          (setq mml2015-epg-secret-key-id-list
 920                (cdr mml2015-epg-secret-key-id-list)))
 921        (mm-set-handle-multipart-parameter
 922         mm-security-handle 'gnus-info "Failed")
 923        (if (eq (car error) 'quit)
 924            (mm-set-handle-multipart-parameter
 925             mm-security-handle 'gnus-details "Quit.")
 926          (mm-set-handle-multipart-parameter
 927           mm-security-handle 'gnus-details (mml2015-format-error error)))))
 928     (when plain
 929       (erase-buffer)
 930       ;; Treat data which epg returns as a unibyte string.
 931       (mm-disable-multibyte)
 932       (insert plain)
 933       (goto-char (point-min))
 934       (while (search-forward "\r\n" nil t)
 935         (replace-match "\n" t t))
 936       (mm-set-handle-multipart-parameter
 937        mm-security-handle 'gnus-info "OK")
 938       (if (epg-context-result-for context 'verify)
 939           (mm-set-handle-multipart-parameter
 940            mm-security-handle 'gnus-details
 941            (mml2015-epg-verify-result-to-string
 942             (epg-context-result-for context 'verify)))))))
 943
 944 (defun mml2015-epg-verify (handle ctl)
 945   (catch 'error
 946     (let ((inhibit-redisplay t)
 947           context plain signature-file part signature)
 948       (when (or (null (setq part (mm-find-raw-part-by-type
 949                                   ctl (or (mm-handle-multipart-ctl-parameter
 950                                            ctl 'protocol)
 951                                           "application/pgp-signature")
 952                                   t)))
 953                 (null (setq signature (mm-find-part-by-type
 954                                        (cdr handle) "application/pgp-signature"
 955                                        nil t))))
 956         (mm-set-handle-multipart-parameter
 957          mm-security-handle 'gnus-info "Corrupted")
 958         (throw 'error handle))
 959       (setq part (mm-replace-in-string part "\n" "\r\n")
 960             signature (mm-get-part signature)
 961             context (epg-make-context))
 962       (condition-case error
 963           (setq plain (epg-verify-string context signature part))
 964         (error
 965          (mm-set-handle-multipart-parameter
 966           mm-security-handle 'gnus-info "Failed")
 967          (if (eq (car error) 'quit)
 968              (mm-set-handle-multipart-parameter
 969               mm-security-handle 'gnus-details "Quit.")
 970            (mm-set-handle-multipart-parameter
 971             mm-security-handle 'gnus-details (mml2015-format-error error)))
 972          (throw 'error handle)))
 973       (mm-set-handle-multipart-parameter
 974        mm-security-handle 'gnus-info
 975        (mml2015-epg-verify-result-to-string
 976         (epg-context-result-for context 'verify)))
 977       handle)))
 978
 979 (defun mml2015-epg-clear-verify ()
 980   (let ((inhibit-redisplay t)
 981         (context (epg-make-context))
 982         (signature (mm-encode-coding-string (buffer-string)
 983                                             coding-system-for-write))
 984         plain)
 985     (condition-case error
 986         (setq plain (epg-verify-string context signature))
 987       (error
 988        (mm-set-handle-multipart-parameter
 989         mm-security-handle 'gnus-info "Failed")
 990        (if (eq (car error) 'quit)
 991            (mm-set-handle-multipart-parameter
 992             mm-security-handle 'gnus-details "Quit.")
 993          (mm-set-handle-multipart-parameter
 994           mm-security-handle 'gnus-details (mml2015-format-error error)))))
 995     (if plain
 996         (progn
 997           (mm-set-handle-multipart-parameter
 998            mm-security-handle 'gnus-info
 999            (mml2015-epg-verify-result-to-string
1000             (epg-context-result-for context 'verify)))
1001           (delete-region (point-min) (point-max))
1002           (insert (mm-decode-coding-string plain coding-system-for-read)))
1003       (mml2015-extract-cleartext-signature))))
1004
1005 (defun mml2015-epg-sign (cont)
1006   (let* ((inhibit-redisplay t)
1007          (context (epg-make-context))
1008          (boundary (mml-compute-boundary cont))
1009          (sender (message-options-get 'message-sender))
1010          (signer-names (or mml2015-signers
1011                            (if (and mml2015-sign-with-sender sender)
1012                                (list (concat "<" sender ">")))))
1013          signer-key
1014          (signers
1015           (or (message-options-get 'mml2015-epg-signers)
1016               (message-options-set
1017                'mml2015-epg-signers
1018                (if (eq mm-sign-option 'guided)
1019                    (epa-select-keys context "\
1020 Select keys for signing.
1021 If no one is selected, default secret key is used.  "
1022                                     signer-names
1023                                     t)
1024                  (if (or sender mml2015-signers)
1025                      (delq nil
1026                            (mapcar
1027                             (lambda (signer)
1028                               (setq signer-key
1029                                     (mml2015-epg-find-usable-secret-key
1030                                      context signer 'sign))
1031                               (unless (or signer-key
1032                                           (y-or-n-p
1033                                            (format
1034                                             "No secret key for %s; skip it? "
1035                                             signer)))
1036                                 (error "No secret key for %s" signer))
1037                               signer-key)
1038                             signer-names)))))))
1039          signature micalg)
1040     (epg-context-set-armor context t)
1041     (epg-context-set-textmode context t)
1042     (epg-context-set-signers context signers)
1043     (if mml2015-cache-passphrase
1044         (epg-context-set-passphrase-callback
1045          context
1046          #'mml2015-epg-passphrase-callback))
1047     (condition-case error
1048         (setq signature (epg-sign-string context (buffer-string) t)
1049               mml2015-epg-secret-key-id-list nil)
1050       (error
1051        (while mml2015-epg-secret-key-id-list
1052          (password-cache-remove (car mml2015-epg-secret-key-id-list))
1053          (setq mml2015-epg-secret-key-id-list
1054                (cdr mml2015-epg-secret-key-id-list)))
1055        (signal (car error) (cdr error))))
1056     (if (epg-context-result-for context 'sign)
1057         (setq micalg (epg-new-signature-digest-algorithm
1058                       (car (epg-context-result-for context 'sign)))))
1059     (goto-char (point-min))
1060     (insert (format "Content-Type: multipart/signed; boundary=\"%s\";\n"
1061                     boundary))
1062     (if micalg
1063         (insert (format "\tmicalg=pgp-%s; "
1064                         (downcase
1065                          (cdr (assq micalg
1066                                     epg-digest-algorithm-alist))))))
1067     (insert "protocol=\"application/pgp-signature\"\n")
1068     (insert (format "\n--%s\n" boundary))
1069     (goto-char (point-max))
1070     (insert (format "\n--%s\n" boundary))
1071     (insert "Content-Type: application/pgp-signature\n\n")
1072     (insert signature)
1073     (goto-char (point-max))
1074     (insert (format "--%s--\n" boundary))
1075     (goto-char (point-max))))
1076
1077 (defun mml2015-epg-encrypt (cont &optional sign)
1078   (let* ((inhibit-redisplay t)
1079          (context (epg-make-context))
1080          (boundary (mml-compute-boundary cont))
1081          (config (epg-configuration))
1082          (recipients (message-options-get 'mml2015-epg-recipients))
1083          cipher
1084          (sender (message-options-get 'message-sender))
1085          (signer-names (or mml2015-signers
1086                            (if (and mml2015-sign-with-sender sender)
1087                                (list (concat "<" sender ">")))))
1088          signers
1089          recipient-key signer-key)
1090     (unless recipients
1091       (setq recipients
1092             (apply #'nconc
1093                    (mapcar
1094                     (lambda (recipient)
1095                       (or (epg-expand-group config recipient)
1096                           (list (concat "<" recipient ">"))))
1097                     (split-string
1098                      (or (message-options-get 'message-recipients)
1099                          (message-options-set 'message-recipients
1100                                               (read-string "Recipients: ")))
1101                      "[ \f\t\n\r\v,]+"))))
1102       (when mml2015-encrypt-to-self
1103         (unless signer-names
1104           (error "Neither message sender nor mml2015-signers are set"))
1105         (setq recipients (nconc recipients signer-names)))
1106       (if (eq mm-encrypt-option 'guided)
1107           (setq recipients
1108                 (epa-select-keys context "\
1109 Select recipients for encryption.
1110 If no one is selected, symmetric encryption will be performed.  "
1111                                  recipients))
1112         (setq recipients
1113               (delq nil
1114                     (mapcar
1115                      (lambda (recipient)
1116                        (setq recipient-key (mml2015-epg-find-usable-key
1117                                             (epg-list-keys context recipient)
1118                                             'encrypt))
1119                        (unless (or recipient-key
1120                                    (y-or-n-p
1121                                     (format "No public key for %s; skip it? "
1122                                             recipient)))
1123                          (error "No public key for %s" recipient))
1124                        recipient-key)
1125                      recipients)))
1126         (unless recipients
1127           (error "No recipient specified")))
1128       (message-options-set 'mml2015-epg-recipients recipients))
1129     (when sign
1130       (setq signers
1131             (or (message-options-get 'mml2015-epg-signers)
1132                 (message-options-set
1133                  'mml2015-epg-signers
1134                  (if (eq mm-sign-option 'guided)
1135                      (epa-select-keys context "\
1136 Select keys for signing.
1137 If no one is selected, default secret key is used.  "
1138                                       signer-names
1139                                       t)
1140                    (if (or sender mml2015-signers)
1141                        (delq nil
1142                              (mapcar
1143                               (lambda (signer)
1144                                 (setq signer-key
1145                                       (mml2015-epg-find-usable-secret-key
1146                                        context signer 'sign))
1147                                 (unless (or signer-key
1148                                             (y-or-n-p
1149                                              (format
1150                                               "No secret key for %s; skip it? "
1151                                               signer)))
1152                                   (error "No secret key for %s" signer))
1153                                 signer-key)
1154                               signer-names)))))))
1155       (epg-context-set-signers context signers))
1156     (epg-context-set-armor context t)
1157     (epg-context-set-textmode context t)
1158     (if mml2015-cache-passphrase
1159         (epg-context-set-passphrase-callback
1160          context
1161          #'mml2015-epg-passphrase-callback))
1162     (condition-case error
1163         (setq cipher
1164               (epg-encrypt-string context (buffer-string) recipients sign
1165                                   mml2015-always-trust)
1166               mml2015-epg-secret-key-id-list nil)
1167       (error
1168        (while mml2015-epg-secret-key-id-list
1169          (password-cache-remove (car mml2015-epg-secret-key-id-list))
1170          (setq mml2015-epg-secret-key-id-list
1171                (cdr mml2015-epg-secret-key-id-list)))
1172        (signal (car error) (cdr error))))
1173     (delete-region (point-min) (point-max))
1174     (goto-char (point-min))
1175     (insert (format "Content-Type: multipart/encrypted; boundary=\"%s\";\n"
1176                     boundary))
1177     (insert "\tprotocol=\"application/pgp-encrypted\"\n\n")
1178     (insert (format "--%s\n" boundary))
1179     (insert "Content-Type: application/pgp-encrypted\n\n")
1180     (insert "Version: 1\n\n")
1181     (insert (format "--%s\n" boundary))
1182     (insert "Content-Type: application/octet-stream\n\n")
1183     (insert cipher)
1184     (goto-char (point-max))
1185     (insert (format "--%s--\n" boundary))
1186     (goto-char (point-max))))
1187
1188 ;;; General wrapper
1189
1190 (autoload 'gnus-buffer-live-p "gnus-util")
1191 (autoload 'gnus-get-buffer-create "gnus")
1192
1193 (defun mml2015-clean-buffer ()
1194   (if (gnus-buffer-live-p mml2015-result-buffer)
1195       (with-current-buffer mml2015-result-buffer
1196         (erase-buffer)
1197         t)
1198     (setq mml2015-result-buffer
1199           (gnus-get-buffer-create " *MML2015 Result*"))
1200     nil))
1201
1202 (defsubst mml2015-clear-decrypt-function ()
1203   (nth 6 (assq mml2015-use mml2015-function-alist)))
1204
1205 (defsubst mml2015-clear-verify-function ()
1206   (nth 5 (assq mml2015-use mml2015-function-alist)))
1207
1208 ;;;###autoload
1209 (defun mml2015-decrypt (handle ctl)
1210   (mml2015-clean-buffer)
1211   (let ((func (nth 4 (assq mml2015-use mml2015-function-alist))))
1212     (if func
1213         (funcall func handle ctl)
1214       handle)))
1215
1216 ;;;###autoload
1217 (defun mml2015-decrypt-test (handle ctl)
1218   mml2015-use)
1219
1220 ;;;###autoload
1221 (defun mml2015-verify (handle ctl)
1222   (mml2015-clean-buffer)
1223   (let ((func (nth 3 (assq mml2015-use mml2015-function-alist))))
1224     (if func
1225         (funcall func handle ctl)
1226       handle)))
1227
1228 ;;;###autoload
1229 (defun mml2015-verify-test (handle ctl)
1230   mml2015-use)
1231
1232 ;;;###autoload
1233 (defun mml2015-encrypt (cont &optional sign)
1234   (mml2015-clean-buffer)
1235   (let ((func (nth 2 (assq mml2015-use mml2015-function-alist))))
1236     (if func
1237         (funcall func cont sign)
1238       (error "Cannot find encrypt function"))))
1239
1240 ;;;###autoload
1241 (defun mml2015-sign (cont)
1242   (mml2015-clean-buffer)
1243   (let ((func (nth 1 (assq mml2015-use mml2015-function-alist))))
1244     (if func
1245         (funcall func cont)
1246       (error "Cannot find sign function"))))
1247
1248 ;;;###autoload
1249 (defun mml2015-self-encrypt ()
1250   (mml2015-encrypt nil))
1251
1252 (provide 'mml2015)
1253
1254 ;;; mml2015.el ends here