code.delx.au - gnu-emacs/blob - lisp/gnus/mml2015.el

   1 ;;; mml2015.el --- MIME Security with Pretty Good Privacy (PGP)
   2
   3 ;; Copyright (C) 2000-2013 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   (with-temp-buffer
 826     (mm-set-buffer-multibyte nil)
 827     (let* ((coding-system-for-write 'binary)
 828            (coding-system-for-read 'binary)
 829            (data (shell-command-to-string
 830                   (format "%s --list-options no-show-photos --attribute-fd 3 --list-keys %s 3>&1 >/dev/null 2>&1"
 831                           epg-gpg-program key-id))))
 832       (when (> (length data) 0)
 833         (insert (substring data 16))
 834         (create-image (buffer-string) nil t)))))
 835
 836 (defun mml2015-epg-key-image-to-string (key-id)
 837   "Return a string with the image of a key, if any"
 838   (let* ((result "")
 839          (key-image (mml2015-epg-key-image key-id)))
 840     (when key-image
 841       (setq result "  ")
 842       (put-text-property 1 2 'display key-image result))
 843     result))
 844
 845 (defun mml2015-epg-signature-to-string (signature)
 846   (concat (epg-signature-to-string signature)
 847           (mml2015-epg-key-image-to-string (epg-signature-key-id signature))))
 848
 849 (defun mml2015-epg-verify-result-to-string (verify-result)
 850   (mapconcat #'mml2015-epg-signature-to-string verify-result "\n"))
 851
 852 (defun mml2015-epg-decrypt (handle ctl)
 853   (catch 'error
 854     (let ((inhibit-redisplay t)
 855           context plain child handles result decrypt-status)
 856       (unless (setq child (mm-find-part-by-type
 857                            (cdr handle)
 858                            "application/octet-stream" nil t))
 859         (mm-set-handle-multipart-parameter
 860          mm-security-handle 'gnus-info "Corrupted")
 861         (throw 'error handle))
 862       (setq context (epg-make-context))
 863       (if mml2015-cache-passphrase
 864           (epg-context-set-passphrase-callback
 865            context
 866            #'mml2015-epg-passphrase-callback))
 867       (condition-case error
 868           (setq plain (epg-decrypt-string context (mm-get-part child))
 869                 mml2015-epg-secret-key-id-list nil)
 870         (error
 871          (while mml2015-epg-secret-key-id-list
 872            (password-cache-remove (car mml2015-epg-secret-key-id-list))
 873            (setq mml2015-epg-secret-key-id-list
 874                  (cdr mml2015-epg-secret-key-id-list)))
 875          (mm-set-handle-multipart-parameter
 876           mm-security-handle 'gnus-info "Failed")
 877          (if (eq (car error) 'quit)
 878              (mm-set-handle-multipart-parameter
 879               mm-security-handle 'gnus-details "Quit.")
 880            (mm-set-handle-multipart-parameter
 881             mm-security-handle 'gnus-details (mml2015-format-error error)))
 882          (throw 'error handle)))
 883       (with-temp-buffer
 884         (insert plain)
 885         (goto-char (point-min))
 886         (while (search-forward "\r\n" nil t)
 887           (replace-match "\n" t t))
 888         (setq handles (mm-dissect-buffer t))
 889         (mm-destroy-parts handle)
 890         (if (epg-context-result-for context 'verify)
 891             (mm-set-handle-multipart-parameter
 892              mm-security-handle 'gnus-info
 893              (concat "OK\n"
 894                      (mml2015-epg-verify-result-to-string
 895                       (epg-context-result-for context 'verify))))
 896           (mm-set-handle-multipart-parameter
 897            mm-security-handle 'gnus-info "OK"))
 898         (if (stringp (car handles))
 899             (mm-set-handle-multipart-parameter
 900              mm-security-handle 'gnus-details
 901              (mm-handle-multipart-ctl-parameter handles 'gnus-details))))
 902         (if (listp (car handles))
 903             handles
 904           (list handles)))))
 905
 906 (defun mml2015-epg-clear-decrypt ()
 907   (let ((inhibit-redisplay t)
 908         (context (epg-make-context))
 909         plain)
 910     (if mml2015-cache-passphrase
 911         (epg-context-set-passphrase-callback
 912          context
 913          #'mml2015-epg-passphrase-callback))
 914     (condition-case error
 915         (setq plain (epg-decrypt-string context (buffer-string))
 916               mml2015-epg-secret-key-id-list nil)
 917       (error
 918        (while mml2015-epg-secret-key-id-list
 919          (password-cache-remove (car mml2015-epg-secret-key-id-list))
 920          (setq mml2015-epg-secret-key-id-list
 921                (cdr mml2015-epg-secret-key-id-list)))
 922        (mm-set-handle-multipart-parameter
 923         mm-security-handle 'gnus-info "Failed")
 924        (if (eq (car error) 'quit)
 925            (mm-set-handle-multipart-parameter
 926             mm-security-handle 'gnus-details "Quit.")
 927          (mm-set-handle-multipart-parameter
 928           mm-security-handle 'gnus-details (mml2015-format-error error)))))
 929     (when plain
 930       (erase-buffer)
 931       ;; Treat data which epg returns as a unibyte string.
 932       (mm-disable-multibyte)
 933       (insert plain)
 934       (goto-char (point-min))
 935       (while (search-forward "\r\n" nil t)
 936         (replace-match "\n" t t))
 937       (mm-set-handle-multipart-parameter
 938        mm-security-handle 'gnus-info "OK")
 939       (if (epg-context-result-for context 'verify)
 940           (mm-set-handle-multipart-parameter
 941            mm-security-handle 'gnus-details
 942            (mml2015-epg-verify-result-to-string
 943             (epg-context-result-for context 'verify)))))))
 944
 945 (defun mml2015-epg-verify (handle ctl)
 946   (catch 'error
 947     (let ((inhibit-redisplay t)
 948           context plain signature-file part signature)
 949       (when (or (null (setq part (mm-find-raw-part-by-type
 950                                   ctl (or (mm-handle-multipart-ctl-parameter
 951                                            ctl 'protocol)
 952                                           "application/pgp-signature")
 953                                   t)))
 954                 (null (setq signature (mm-find-part-by-type
 955                                        (cdr handle) "application/pgp-signature"
 956                                        nil t))))
 957         (mm-set-handle-multipart-parameter
 958          mm-security-handle 'gnus-info "Corrupted")
 959         (throw 'error handle))
 960       (setq part (mm-replace-in-string part "\n" "\r\n")
 961             signature (mm-get-part signature)
 962             context (epg-make-context))
 963       (condition-case error
 964           (setq plain (epg-verify-string context signature part))
 965         (error
 966          (mm-set-handle-multipart-parameter
 967           mm-security-handle 'gnus-info "Failed")
 968          (if (eq (car error) 'quit)
 969              (mm-set-handle-multipart-parameter
 970               mm-security-handle 'gnus-details "Quit.")
 971            (mm-set-handle-multipart-parameter
 972             mm-security-handle 'gnus-details (mml2015-format-error error)))
 973          (throw 'error handle)))
 974       (mm-set-handle-multipart-parameter
 975        mm-security-handle 'gnus-info
 976        (mml2015-epg-verify-result-to-string
 977         (epg-context-result-for context 'verify)))
 978       handle)))
 979
 980 (defun mml2015-epg-clear-verify ()
 981   (let ((inhibit-redisplay t)
 982         (context (epg-make-context))
 983         (signature (mm-encode-coding-string (buffer-string)
 984                                             coding-system-for-write))
 985         plain)
 986     (condition-case error
 987         (setq plain (epg-verify-string context signature))
 988       (error
 989        (mm-set-handle-multipart-parameter
 990         mm-security-handle 'gnus-info "Failed")
 991        (if (eq (car error) 'quit)
 992            (mm-set-handle-multipart-parameter
 993             mm-security-handle 'gnus-details "Quit.")
 994          (mm-set-handle-multipart-parameter
 995           mm-security-handle 'gnus-details (mml2015-format-error error)))))
 996     (if plain
 997         (progn
 998           (mm-set-handle-multipart-parameter
 999            mm-security-handle 'gnus-info
1000            (mml2015-epg-verify-result-to-string
1001             (epg-context-result-for context 'verify)))
1002           (delete-region (point-min) (point-max))
1003           (insert (mm-decode-coding-string plain coding-system-for-read)))
1004       (mml2015-extract-cleartext-signature))))
1005
1006 (defun mml2015-epg-sign (cont)
1007   (let* ((inhibit-redisplay t)
1008          (context (epg-make-context))
1009          (boundary (mml-compute-boundary cont))
1010          (sender (message-options-get 'message-sender))
1011          (signer-names (or mml2015-signers
1012                            (if (and mml2015-sign-with-sender sender)
1013                                (list (concat "<" sender ">")))))
1014          signer-key
1015          (signers
1016           (or (message-options-get 'mml2015-epg-signers)
1017               (message-options-set
1018                'mml2015-epg-signers
1019                (if (eq mm-sign-option 'guided)
1020                    (epa-select-keys context "\
1021 Select keys for signing.
1022 If no one is selected, default secret key is used.  "
1023                                     signer-names
1024                                     t)
1025                  (if (or sender mml2015-signers)
1026                      (delq nil
1027                            (mapcar
1028                             (lambda (signer)
1029                               (setq signer-key
1030                                     (mml2015-epg-find-usable-secret-key
1031                                      context signer 'sign))
1032                               (unless (or signer-key
1033                                           (y-or-n-p
1034                                            (format
1035                                             "No secret key for %s; skip it? "
1036                                             signer)))
1037                                 (error "No secret key for %s" signer))
1038                               signer-key)
1039                             signer-names)))))))
1040          signature micalg)
1041     (epg-context-set-armor context t)
1042     (epg-context-set-textmode context t)
1043     (epg-context-set-signers context signers)
1044     (if mml2015-cache-passphrase
1045         (epg-context-set-passphrase-callback
1046          context
1047          #'mml2015-epg-passphrase-callback))
1048     (condition-case error
1049         (setq signature (epg-sign-string context (buffer-string) t)
1050               mml2015-epg-secret-key-id-list nil)
1051       (error
1052        (while mml2015-epg-secret-key-id-list
1053          (password-cache-remove (car mml2015-epg-secret-key-id-list))
1054          (setq mml2015-epg-secret-key-id-list
1055                (cdr mml2015-epg-secret-key-id-list)))
1056        (signal (car error) (cdr error))))
1057     (if (epg-context-result-for context 'sign)
1058         (setq micalg (epg-new-signature-digest-algorithm
1059                       (car (epg-context-result-for context 'sign)))))
1060     (goto-char (point-min))
1061     (insert (format "Content-Type: multipart/signed; boundary=\"%s\";\n"
1062                     boundary))
1063     (if micalg
1064         (insert (format "\tmicalg=pgp-%s; "
1065                         (downcase
1066                          (cdr (assq micalg
1067                                     epg-digest-algorithm-alist))))))
1068     (insert "protocol=\"application/pgp-signature\"\n")
1069     (insert (format "\n--%s\n" boundary))
1070     (goto-char (point-max))
1071     (insert (format "\n--%s\n" boundary))
1072     (insert "Content-Type: application/pgp-signature\n\n")
1073     (insert signature)
1074     (goto-char (point-max))
1075     (insert (format "--%s--\n" boundary))
1076     (goto-char (point-max))))
1077
1078 (defun mml2015-epg-encrypt (cont &optional sign)
1079   (let* ((inhibit-redisplay t)
1080          (context (epg-make-context))
1081          (boundary (mml-compute-boundary cont))
1082          (config (epg-configuration))
1083          (recipients (message-options-get 'mml2015-epg-recipients))
1084          cipher
1085          (sender (message-options-get 'message-sender))
1086          (signer-names (or mml2015-signers
1087                            (if (and mml2015-sign-with-sender sender)
1088                                (list (concat "<" sender ">")))))
1089          signers
1090          recipient-key signer-key)
1091     (unless recipients
1092       (setq recipients
1093             (apply #'nconc
1094                    (mapcar
1095                     (lambda (recipient)
1096                       (or (epg-expand-group config recipient)
1097                           (list (concat "<" recipient ">"))))
1098                     (split-string
1099                      (or (message-options-get 'message-recipients)
1100                          (message-options-set 'message-recipients
1101                                               (read-string "Recipients: ")))
1102                      "[ \f\t\n\r\v,]+"))))
1103       (when mml2015-encrypt-to-self
1104         (unless signer-names
1105           (error "Neither message sender nor mml2015-signers are set"))
1106         (setq recipients (nconc recipients signer-names)))
1107       (if (eq mm-encrypt-option 'guided)
1108           (setq recipients
1109                 (epa-select-keys context "\
1110 Select recipients for encryption.
1111 If no one is selected, symmetric encryption will be performed.  "
1112                                  recipients))
1113         (setq recipients
1114               (delq nil
1115                     (mapcar
1116                      (lambda (recipient)
1117                        (setq recipient-key (mml2015-epg-find-usable-key
1118                                             (epg-list-keys context recipient)
1119                                             'encrypt))
1120                        (unless (or recipient-key
1121                                    (y-or-n-p
1122                                     (format "No public key for %s; skip it? "
1123                                             recipient)))
1124                          (error "No public key for %s" recipient))
1125                        recipient-key)
1126                      recipients)))
1127         (unless recipients
1128           (error "No recipient specified")))
1129       (message-options-set 'mml2015-epg-recipients recipients))
1130     (when sign
1131       (setq signers
1132             (or (message-options-get 'mml2015-epg-signers)
1133                 (message-options-set
1134                  'mml2015-epg-signers
1135                  (if (eq mm-sign-option 'guided)
1136                      (epa-select-keys context "\
1137 Select keys for signing.
1138 If no one is selected, default secret key is used.  "
1139                                       signer-names
1140                                       t)
1141                    (if (or sender mml2015-signers)
1142                        (delq nil
1143                              (mapcar
1144                               (lambda (signer)
1145                                 (setq signer-key
1146                                       (mml2015-epg-find-usable-secret-key
1147                                        context signer 'sign))
1148                                 (unless (or signer-key
1149                                             (y-or-n-p
1150                                              (format
1151                                               "No secret key for %s; skip it? "
1152                                               signer)))
1153                                   (error "No secret key for %s" signer))
1154                                 signer-key)
1155                               signer-names)))))))
1156       (epg-context-set-signers context signers))
1157     (epg-context-set-armor context t)
1158     (epg-context-set-textmode context t)
1159     (if mml2015-cache-passphrase
1160         (epg-context-set-passphrase-callback
1161          context
1162          #'mml2015-epg-passphrase-callback))
1163     (condition-case error
1164         (setq cipher
1165               (epg-encrypt-string context (buffer-string) recipients sign
1166                                   mml2015-always-trust)
1167               mml2015-epg-secret-key-id-list nil)
1168       (error
1169        (while mml2015-epg-secret-key-id-list
1170          (password-cache-remove (car mml2015-epg-secret-key-id-list))
1171          (setq mml2015-epg-secret-key-id-list
1172                (cdr mml2015-epg-secret-key-id-list)))
1173        (signal (car error) (cdr error))))
1174     (delete-region (point-min) (point-max))
1175     (goto-char (point-min))
1176     (insert (format "Content-Type: multipart/encrypted; boundary=\"%s\";\n"
1177                     boundary))
1178     (insert "\tprotocol=\"application/pgp-encrypted\"\n\n")
1179     (insert (format "--%s\n" boundary))
1180     (insert "Content-Type: application/pgp-encrypted\n\n")
1181     (insert "Version: 1\n\n")
1182     (insert (format "--%s\n" boundary))
1183     (insert "Content-Type: application/octet-stream\n\n")
1184     (insert cipher)
1185     (goto-char (point-max))
1186     (insert (format "--%s--\n" boundary))
1187     (goto-char (point-max))))
1188
1189 ;;; General wrapper
1190
1191 (autoload 'gnus-buffer-live-p "gnus-util")
1192 (autoload 'gnus-get-buffer-create "gnus")
1193
1194 (defun mml2015-clean-buffer ()
1195   (if (gnus-buffer-live-p mml2015-result-buffer)
1196       (with-current-buffer mml2015-result-buffer
1197         (erase-buffer)
1198         t)
1199     (setq mml2015-result-buffer
1200           (gnus-get-buffer-create " *MML2015 Result*"))
1201     nil))
1202
1203 (defsubst mml2015-clear-decrypt-function ()
1204   (nth 6 (assq mml2015-use mml2015-function-alist)))
1205
1206 (defsubst mml2015-clear-verify-function ()
1207   (nth 5 (assq mml2015-use mml2015-function-alist)))
1208
1209 ;;;###autoload
1210 (defun mml2015-decrypt (handle ctl)
1211   (mml2015-clean-buffer)
1212   (let ((func (nth 4 (assq mml2015-use mml2015-function-alist))))
1213     (if func
1214         (funcall func handle ctl)
1215       handle)))
1216
1217 ;;;###autoload
1218 (defun mml2015-decrypt-test (handle ctl)
1219   mml2015-use)
1220
1221 ;;;###autoload
1222 (defun mml2015-verify (handle ctl)
1223   (mml2015-clean-buffer)
1224   (let ((func (nth 3 (assq mml2015-use mml2015-function-alist))))
1225     (if func
1226         (funcall func handle ctl)
1227       handle)))
1228
1229 ;;;###autoload
1230 (defun mml2015-verify-test (handle ctl)
1231   mml2015-use)
1232
1233 ;;;###autoload
1234 (defun mml2015-encrypt (cont &optional sign)
1235   (mml2015-clean-buffer)
1236   (let ((func (nth 2 (assq mml2015-use mml2015-function-alist))))
1237     (if func
1238         (funcall func cont sign)
1239       (error "Cannot find encrypt function"))))
1240
1241 ;;;###autoload
1242 (defun mml2015-sign (cont)
1243   (mml2015-clean-buffer)
1244   (let ((func (nth 1 (assq mml2015-use mml2015-function-alist))))
1245     (if func
1246         (funcall func cont)
1247       (error "Cannot find sign function"))))
1248
1249 ;;;###autoload
1250 (defun mml2015-self-encrypt ()
1251   (mml2015-encrypt nil))
1252
1253 (provide 'mml2015)
1254
1255 ;;; mml2015.el ends here