lisp/gnus/mml2015.el

   1 ;;; mml2015.el --- MIME Security with Pretty Good Privacy (PGP)
   2
   3 ;; Copyright (C) 2000-2015 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   (if (locate-library "password-cache")
  32       (require 'password-cache)
  33     (require 'password)))
  34
  35 (eval-when-compile (require 'cl))
  36 (require 'mm-decode)
  37 (require 'mm-util)
  38 (require 'mml)
  39 (require 'mml-sec)
  40
  41 (defvar mc-pgp-always-sign)
  42
  43 (declare-function epg-check-configuration "ext:epg-config"
  44                   (config &optional minimum-version))
  45 (declare-function epg-configuration "ext:epg-config" ())
  46
  47 ;; Maybe this should be in eg mml-sec.el (and have a different name).
  48 ;; Then mml1991 would not need to require mml2015, and mml1991-use
  49 ;; could be removed.
  50 (defvar mml2015-use (or
  51                      (progn
  52                        (ignore-errors (require 'epg-config))
  53                        (and (fboundp 'epg-check-configuration)
  54                            'epg))
  55                      (progn
  56                        (let ((abs-file (locate-library "pgg")))
  57                          ;; Don't load PGG if it is marked as obsolete
  58                          ;; (Emacs 24).
  59                          (when (and abs-file
  60                                     (not (string-match "/obsolete/[^/]*\\'"
  61                                                        abs-file)))
  62                            (ignore-errors (require 'pgg))
  63                            (and (fboundp 'pgg-sign-region)
  64                                 'pgg))))
  65                      (progn (ignore-errors
  66                               (load "mc-toplev"))
  67                             (and (fboundp 'mc-encrypt-generic)
  68                                  (fboundp 'mc-sign-generic)
  69                                  (fboundp 'mc-cleanup-recipient-headers)
  70                                  'mailcrypt)))
  71   "The package used for PGP/MIME.
  72 Valid packages include `epg', `pgg' and `mailcrypt'.")
  73
  74 ;; Something is not RFC2015.
  75 (defvar mml2015-function-alist
  76   '((mailcrypt mml2015-mailcrypt-sign
  77                mml2015-mailcrypt-encrypt
  78                mml2015-mailcrypt-verify
  79                mml2015-mailcrypt-decrypt
  80                mml2015-mailcrypt-clear-verify
  81                mml2015-mailcrypt-clear-decrypt)
  82     (pgg mml2015-pgg-sign
  83          mml2015-pgg-encrypt
  84          mml2015-pgg-verify
  85          mml2015-pgg-decrypt
  86          mml2015-pgg-clear-verify
  87          mml2015-pgg-clear-decrypt)
  88     (epg mml2015-epg-sign
  89          mml2015-epg-encrypt
  90          mml2015-epg-verify
  91          mml2015-epg-decrypt
  92          mml2015-epg-clear-verify
  93          mml2015-epg-clear-decrypt))
  94   "Alist of PGP/MIME functions.")
  95
  96 (defvar mml2015-result-buffer nil)
  97
  98 (defcustom mml2015-unabbrev-trust-alist
  99   '(("TRUST_UNDEFINED" . nil)
 100     ("TRUST_NEVER"     . nil)
 101     ("TRUST_MARGINAL"  . t)
 102     ("TRUST_FULLY"     . t)
 103     ("TRUST_ULTIMATE"  . t))
 104   "Map GnuPG trust output values to a boolean saying if you trust the key."
 105   :version "22.1"
 106   :group 'mime-security
 107   :type '(repeat (cons (regexp :tag "GnuPG output regexp")
 108                        (boolean :tag "Trust key"))))
 109
 110 (defcustom mml2015-cache-passphrase mml-secure-cache-passphrase
 111   "If t, cache passphrase."
 112   :group 'mime-security
 113   :type 'boolean)
 114
 115 (defcustom mml2015-passphrase-cache-expiry mml-secure-passphrase-cache-expiry
 116   "How many seconds the passphrase is cached.
 117 Whether the passphrase is cached at all is controlled by
 118 `mml2015-cache-passphrase'."
 119   :group 'mime-security
 120   :type 'integer)
 121
 122 (defcustom mml2015-signers nil
 123   "A list of your own key ID(s) which will be used to sign a message.
 124 If set, it overrides the setting of `mml2015-sign-with-sender'."
 125   :group 'mime-security
 126   :type '(repeat (string :tag "Key ID")))
 127
 128 (defcustom mml2015-sign-with-sender nil
 129   "If t, use message sender so find a key to sign with."
 130   :group 'mime-security
 131   :type 'boolean
 132   :version "24.1")
 133
 134 (defcustom mml2015-encrypt-to-self nil
 135   "If t, add your own key ID to recipient list when encryption."
 136   :group 'mime-security
 137   :type 'boolean)
 138
 139 (defcustom mml2015-always-trust t
 140   "If t, GnuPG skip key validation on encryption."
 141   :group 'mime-security
 142   :type 'boolean)
 143
 144 (defcustom mml2015-maximum-key-image-dimension 64
 145   "The maximum dimension (width or height) of any key images."
 146   :version "24.4"
 147   :group 'mime-security
 148   :type 'integer)
 149
 150 (defcustom mml2015-display-key-image t
 151   "If t, try to display key images."
 152   :version "24.5"
 153   :group 'mime-security
 154   :type 'boolean)
 155
 156 ;; Extract plaintext from cleartext signature.  IMO, this kind of task
 157 ;; should be done by GnuPG rather than Elisp, but older PGP backends
 158 ;; (such as Mailcrypt, and PGG) discard the output from GnuPG.
 159 (defun mml2015-extract-cleartext-signature ()
 160   ;; Daiki Ueno in
 161   ;; <54a15d860801080142l70b95d7dkac4bf51a86196011@mail.gmail.com>: ``I still
 162   ;; believe that the right way is to use the plaintext output from GnuPG as
 163   ;; it is, and mml2015-extract-cleartext-signature is just a kludge for
 164   ;; misdesigned libraries like PGG, which have no ability to do that.  So, I
 165   ;; think it should not have descriptive documentation.''
 166   ;;
 167   ;; This function doesn't handle NotDashEscaped correctly.  EasyPG handles it
 168   ;; correctly.
 169   ;; http://thread.gmane.org/gmane.emacs.gnus.general/66062/focus=66082
 170   ;; http://thread.gmane.org/gmane.emacs.gnus.general/65087/focus=65109
 171   (goto-char (point-min))
 172   (forward-line)
 173   ;; We need to be careful not to strip beyond the armor headers.
 174   ;; Previously, an attacker could replace the text inside our
 175   ;; markup with trailing garbage by injecting whitespace into the
 176   ;; message.
 177   (while (looking-at "Hash:")           ; The only header allowed in cleartext
 178     (forward-line))                     ; signatures according to RFC2440.
 179   (when (looking-at "[\t ]*$")
 180     (forward-line))
 181   (delete-region (point-min) (point))
 182   (if (re-search-forward "^-----BEGIN PGP SIGNATURE-----" nil t)
 183       (delete-region (match-beginning 0) (point-max)))
 184   (goto-char (point-min))
 185   (while (re-search-forward "^- " nil t)
 186     (replace-match "" t t)
 187     (forward-line 1)))
 188
 189 ;;; mailcrypt wrapper
 190
 191 (autoload 'mailcrypt-decrypt "mailcrypt")
 192 (autoload 'mailcrypt-verify "mailcrypt")
 193 (autoload 'mc-pgp-always-sign "mailcrypt")
 194 (autoload 'mc-encrypt-generic "mc-toplev")
 195 (autoload 'mc-cleanup-recipient-headers "mc-toplev")
 196 (autoload 'mc-sign-generic "mc-toplev")
 197
 198 (defvar mml2015-decrypt-function 'mailcrypt-decrypt)
 199 (defvar mml2015-verify-function 'mailcrypt-verify)
 200
 201 (defun mml2015-format-error (err)
 202   (if (stringp (cadr err))
 203       (cadr err)
 204     (format "%S" (cdr err))))
 205
 206 (defun mml2015-mailcrypt-decrypt (handle ctl)
 207   (catch 'error
 208     (let (child handles result)
 209       (unless (setq child (mm-find-part-by-type
 210                            (cdr handle)
 211                            "application/octet-stream" nil t))
 212         (mm-set-handle-multipart-parameter
 213          mm-security-handle 'gnus-info "Corrupted")
 214         (throw 'error handle))
 215       (with-temp-buffer
 216         (mm-insert-part child)
 217         (setq result
 218               (condition-case err
 219                   (funcall mml2015-decrypt-function)
 220                 (error
 221                  (mm-set-handle-multipart-parameter
 222                   mm-security-handle 'gnus-details (mml2015-format-error err))
 223                  nil)
 224                 (quit
 225                  (mm-set-handle-multipart-parameter
 226                   mm-security-handle 'gnus-details "Quit.")
 227                  nil)))
 228         (unless (car result)
 229           (mm-set-handle-multipart-parameter
 230            mm-security-handle 'gnus-info "Failed")
 231           (throw 'error handle))
 232         (setq handles (mm-dissect-buffer t)))
 233       (mm-destroy-parts handle)
 234       (mm-set-handle-multipart-parameter
 235        mm-security-handle 'gnus-info
 236        (concat "OK"
 237                (let ((sig (with-current-buffer mml2015-result-buffer
 238                             (mml2015-gpg-extract-signature-details))))
 239                  (concat ", Signer: " sig))))
 240       (if (listp (car handles))
 241           handles
 242         (list handles)))))
 243
 244 (defun mml2015-gpg-pretty-print-fpr (fingerprint)
 245   (let* ((result "")
 246          (fpr-length (string-width fingerprint))
 247          (n-slice 0)
 248          slice)
 249     (setq fingerprint (string-to-list fingerprint))
 250     (while fingerprint
 251       (setq fpr-length (- fpr-length 4))
 252       (setq slice (butlast fingerprint fpr-length))
 253       (setq fingerprint (nthcdr 4 fingerprint))
 254       (setq n-slice (1+ n-slice))
 255       (setq result
 256             (concat
 257              result
 258              (case n-slice
 259                (1  slice)
 260                (otherwise (concat " " slice))))))
 261     result))
 262
 263 (defun mml2015-gpg-extract-signature-details ()
 264   (goto-char (point-min))
 265   (let* ((expired (re-search-forward
 266                    "^\\[GNUPG:\\] SIGEXPIRED$"
 267                    nil t))
 268          (signer (and (re-search-forward
 269                        "^\\[GNUPG:\\] GOODSIG \\([0-9A-Za-z]*\\) \\(.*\\)$"
 270                        nil t)
 271                       (cons (match-string 1) (match-string 2))))
 272          (fprint (and (re-search-forward
 273                        "^\\[GNUPG:\\] VALIDSIG \\([0-9a-zA-Z]*\\) "
 274                        nil t)
 275                       (match-string 1)))
 276          (trust  (and (re-search-forward
 277                        "^\\[GNUPG:\\] \\(TRUST_.*\\)$"
 278                        nil t)
 279                       (match-string 1)))
 280          (trust-good-enough-p
 281           (cdr (assoc trust mml2015-unabbrev-trust-alist))))
 282     (cond ((and signer fprint)
 283            (concat (cdr signer)
 284                    (unless trust-good-enough-p
 285                      (concat "\nUntrusted, Fingerprint: "
 286                              (mml2015-gpg-pretty-print-fpr fprint)))
 287                    (when expired
 288                      (format "\nWARNING: Signature from expired key (%s)"
 289                              (car signer)))))
 290           ((re-search-forward
 291             "^\\(gpg: \\)?Good signature from \"\\(.*\\)\"$" nil t)
 292            (match-string 2))
 293           (t
 294            "From unknown user"))))
 295
 296 (defun mml2015-mailcrypt-clear-decrypt ()
 297   (let (result)
 298     (setq result
 299           (condition-case err
 300               (funcall mml2015-decrypt-function)
 301             (error
 302              (mm-set-handle-multipart-parameter
 303               mm-security-handle 'gnus-details (mml2015-format-error err))
 304              nil)
 305             (quit
 306              (mm-set-handle-multipart-parameter
 307               mm-security-handle 'gnus-details "Quit.")
 308              nil)))
 309     (if (car result)
 310         (mm-set-handle-multipart-parameter
 311          mm-security-handle 'gnus-info "OK")
 312       (mm-set-handle-multipart-parameter
 313        mm-security-handle 'gnus-info "Failed"))))
 314
 315 (defun mml2015-fix-micalg (alg)
 316   (and alg
 317        ;; Mutt/1.2.5i has seen sending micalg=php-sha1
 318        (upcase (if (string-match "^p[gh]p-" alg)
 319                    (substring alg (match-end 0))
 320                  alg))))
 321
 322 (defun mml2015-mailcrypt-verify (handle ctl)
 323   (catch 'error
 324     (let (part)
 325       (unless (setq part (mm-find-raw-part-by-type
 326                           ctl (or (mm-handle-multipart-ctl-parameter
 327                                    ctl 'protocol)
 328                                   "application/pgp-signature")
 329                           t))
 330         (mm-set-handle-multipart-parameter
 331          mm-security-handle 'gnus-info "Corrupted")
 332         (throw 'error handle))
 333       (with-temp-buffer
 334         (insert "-----BEGIN PGP SIGNED MESSAGE-----\n")
 335         (insert (format "Hash: %s\n\n"
 336                         (or (mml2015-fix-micalg
 337                              (mm-handle-multipart-ctl-parameter
 338                               ctl 'micalg))
 339                             "SHA1")))
 340         (save-restriction
 341           (narrow-to-region (point) (point))
 342           (insert part "\n")
 343           (goto-char (point-min))
 344           (while (not (eobp))
 345             (if (looking-at "^-")
 346                 (insert "- "))
 347             (forward-line)))
 348         (unless (setq part (mm-find-part-by-type
 349                             (cdr handle) "application/pgp-signature" nil t))
 350           (mm-set-handle-multipart-parameter
 351            mm-security-handle 'gnus-info "Corrupted")
 352           (throw 'error handle))
 353         (save-restriction
 354           (narrow-to-region (point) (point))
 355           (mm-insert-part part)
 356           (goto-char (point-min))
 357           (if (re-search-forward "^-----BEGIN PGP [^-]+-----\r?$" nil t)
 358               (replace-match "-----BEGIN PGP SIGNATURE-----" t t))
 359           (if (re-search-forward "^-----END PGP [^-]+-----\r?$" nil t)
 360               (replace-match "-----END PGP SIGNATURE-----" t t)))
 361         (let ((mc-gpg-debug-buffer (get-buffer-create " *gnus gpg debug*")))
 362           (unless (condition-case err
 363                       (prog1
 364                           (funcall mml2015-verify-function)
 365                         (if (get-buffer " *mailcrypt stderr temp")
 366                             (mm-set-handle-multipart-parameter
 367                              mm-security-handle 'gnus-details
 368                              (with-current-buffer " *mailcrypt stderr temp"
 369                                (buffer-string))))
 370                         (if (get-buffer " *mailcrypt stdout temp")
 371                             (kill-buffer " *mailcrypt stdout temp"))
 372                         (if (get-buffer " *mailcrypt stderr temp")
 373                             (kill-buffer " *mailcrypt stderr temp"))
 374                         (if (get-buffer " *mailcrypt status temp")
 375                             (kill-buffer " *mailcrypt status temp"))
 376                         (if (get-buffer mc-gpg-debug-buffer)
 377                             (kill-buffer mc-gpg-debug-buffer)))
 378                     (error
 379                      (mm-set-handle-multipart-parameter
 380                       mm-security-handle 'gnus-details (mml2015-format-error err))
 381                      nil)
 382                     (quit
 383                      (mm-set-handle-multipart-parameter
 384                       mm-security-handle 'gnus-details "Quit.")
 385                      nil))
 386             (mm-set-handle-multipart-parameter
 387              mm-security-handle 'gnus-info "Failed")
 388             (throw 'error handle))))
 389       (mm-set-handle-multipart-parameter
 390        mm-security-handle 'gnus-info "OK")
 391       handle)))
 392
 393 (defun mml2015-mailcrypt-clear-verify ()
 394   (let ((mc-gpg-debug-buffer (get-buffer-create " *gnus gpg debug*")))
 395     (if (condition-case err
 396             (prog1
 397                 (funcall mml2015-verify-function)
 398               (if (get-buffer " *mailcrypt stderr temp")
 399                   (mm-set-handle-multipart-parameter
 400                    mm-security-handle 'gnus-details
 401                    (with-current-buffer " *mailcrypt stderr temp"
 402                      (buffer-string))))
 403               (if (get-buffer " *mailcrypt stdout temp")
 404                   (kill-buffer " *mailcrypt stdout temp"))
 405               (if (get-buffer " *mailcrypt stderr temp")
 406                   (kill-buffer " *mailcrypt stderr temp"))
 407               (if (get-buffer " *mailcrypt status temp")
 408                   (kill-buffer " *mailcrypt status temp"))
 409               (if (get-buffer mc-gpg-debug-buffer)
 410                   (kill-buffer mc-gpg-debug-buffer)))
 411           (error
 412            (mm-set-handle-multipart-parameter
 413             mm-security-handle 'gnus-details (mml2015-format-error err))
 414            nil)
 415           (quit
 416            (mm-set-handle-multipart-parameter
 417             mm-security-handle 'gnus-details "Quit.")
 418            nil))
 419         (mm-set-handle-multipart-parameter
 420          mm-security-handle 'gnus-info "OK")
 421       (mm-set-handle-multipart-parameter
 422        mm-security-handle 'gnus-info "Failed")))
 423   (mml2015-extract-cleartext-signature))
 424
 425 (defun mml2015-mailcrypt-sign (cont)
 426   (mc-sign-generic (message-options-get 'message-sender)
 427                    nil nil nil nil)
 428   (let ((boundary (mml-compute-boundary cont))
 429         hash point)
 430     (goto-char (point-min))
 431     (unless (re-search-forward "^-----BEGIN PGP SIGNED MESSAGE-----\r?$" nil t)
 432       (error "Cannot find signed begin line"))
 433     (goto-char (match-beginning 0))
 434     (forward-line 1)
 435     (unless (looking-at "Hash:[ \t]*\\([a-zA-Z0-9]+\\)")
 436       (error "Cannot not find PGP hash"))
 437     (setq hash (match-string 1))
 438     (unless (re-search-forward "^$" nil t)
 439       (error "Cannot not find PGP message"))
 440     (forward-line 1)
 441     (delete-region (point-min) (point))
 442     (insert (format "Content-Type: multipart/signed; boundary=\"%s\";\n"
 443                     boundary))
 444     (insert (format "\tmicalg=pgp-%s; protocol=\"application/pgp-signature\"\n"
 445                     (downcase hash)))
 446     (insert (format "\n--%s\n" boundary))
 447     (setq point (point))
 448     (goto-char (point-max))
 449     (unless (re-search-backward "^-----END PGP SIGNATURE-----\r?$" nil t)
 450       (error "Cannot find signature part"))
 451     (replace-match "-----END PGP MESSAGE-----" t t)
 452     (goto-char (match-beginning 0))
 453     (unless (re-search-backward "^-----BEGIN PGP SIGNATURE-----\r?$"
 454                                 nil t)
 455       (error "Cannot find signature part"))
 456     (replace-match "-----BEGIN PGP MESSAGE-----" t t)
 457     (goto-char (match-beginning 0))
 458     (save-restriction
 459       (narrow-to-region point (point))
 460       (goto-char point)
 461       (while (re-search-forward "^- -" nil t)
 462         (replace-match "-" t t))
 463       (goto-char (point-max)))
 464     (insert (format "--%s\n" boundary))
 465     (insert "Content-Type: application/pgp-signature\n\n")
 466     (goto-char (point-max))
 467     (insert (format "--%s--\n" boundary))
 468     (goto-char (point-max))))
 469
 470 ;; We require mm-decode, which requires mm-bodies, which autoloads
 471 ;; message-options-get (!).
 472 (declare-function message-options-set "message" (symbol value))
 473
 474 (defun mml2015-mailcrypt-encrypt (cont &optional sign)
 475   (let ((mc-pgp-always-sign
 476          (or mc-pgp-always-sign
 477              sign
 478              (eq t (or (message-options-get 'message-sign-encrypt)
 479                        (message-options-set
 480                         'message-sign-encrypt
 481                         (or (y-or-n-p "Sign the message? ")
 482                             'not))))
 483              'never)))
 484     (mm-with-unibyte-current-buffer
 485       (mc-encrypt-generic
 486        (or (message-options-get 'message-recipients)
 487            (message-options-set 'message-recipients
 488                               (mc-cleanup-recipient-headers
 489                                (read-string "Recipients: "))))
 490        nil nil nil
 491        (message-options-get 'message-sender))))
 492   (goto-char (point-min))
 493   (unless (looking-at "-----BEGIN PGP MESSAGE-----")
 494     (error "Fail to encrypt the message"))
 495   (let ((boundary (mml-compute-boundary cont)))
 496     (insert (format "Content-Type: multipart/encrypted; boundary=\"%s\";\n"
 497                     boundary))
 498     (insert "\tprotocol=\"application/pgp-encrypted\"\n\n")
 499     (insert (format "--%s\n" boundary))
 500     (insert "Content-Type: application/pgp-encrypted\n\n")
 501     (insert "Version: 1\n\n")
 502     (insert (format "--%s\n" boundary))
 503     (insert "Content-Type: application/octet-stream\n\n")
 504     (goto-char (point-max))
 505     (insert (format "--%s--\n" boundary))
 506     (goto-char (point-max))))
 507
 508 ;;; pgg wrapper
 509
 510 (defvar pgg-default-user-id)
 511 (defvar pgg-errors-buffer)
 512 (defvar pgg-output-buffer)
 513
 514 (autoload 'pgg-decrypt-region "pgg")
 515 (autoload 'pgg-verify-region "pgg")
 516 (autoload 'pgg-sign-region "pgg")
 517 (autoload 'pgg-encrypt-region "pgg")
 518 (autoload 'pgg-parse-armor "pgg-parse")
 519
 520 (defun mml2015-pgg-decrypt (handle ctl)
 521   (catch 'error
 522     (let ((pgg-errors-buffer mml2015-result-buffer)
 523           child handles result decrypt-status)
 524       (unless (setq child (mm-find-part-by-type
 525                            (cdr handle)
 526                            "application/octet-stream" nil t))
 527         (mm-set-handle-multipart-parameter
 528          mm-security-handle 'gnus-info "Corrupted")
 529         (throw 'error handle))
 530       (with-temp-buffer
 531         (mm-insert-part child)
 532         (if (condition-case err
 533                 (prog1
 534                     (pgg-decrypt-region (point-min) (point-max))
 535                   (setq decrypt-status
 536                         (with-current-buffer mml2015-result-buffer
 537                           (buffer-string)))
 538                   (mm-set-handle-multipart-parameter
 539                    mm-security-handle 'gnus-details
 540                    decrypt-status))
 541               (error
 542                (mm-set-handle-multipart-parameter
 543                 mm-security-handle 'gnus-details (mml2015-format-error err))
 544                nil)
 545               (quit
 546                (mm-set-handle-multipart-parameter
 547                 mm-security-handle 'gnus-details "Quit.")
 548                nil))
 549             (with-current-buffer pgg-output-buffer
 550               (goto-char (point-min))
 551               (while (search-forward "\r\n" nil t)
 552                 (replace-match "\n" t t))
 553               (setq handles (mm-dissect-buffer t))
 554               (mm-destroy-parts handle)
 555               (mm-set-handle-multipart-parameter
 556                mm-security-handle 'gnus-info "OK")
 557               (mm-set-handle-multipart-parameter
 558                mm-security-handle 'gnus-details
 559                (concat decrypt-status
 560                        (when (stringp (car handles))
 561                          "\n" (mm-handle-multipart-ctl-parameter
 562                                handles 'gnus-details))))
 563               (if (listp (car handles))
 564                   handles
 565                 (list handles)))
 566           (mm-set-handle-multipart-parameter
 567            mm-security-handle 'gnus-info "Failed")
 568           (throw 'error handle))))))
 569
 570 (defun mml2015-pgg-clear-decrypt ()
 571   (let ((pgg-errors-buffer mml2015-result-buffer))
 572     (if (prog1
 573             (pgg-decrypt-region (point-min) (point-max))
 574           (mm-set-handle-multipart-parameter
 575            mm-security-handle 'gnus-details
 576            (with-current-buffer mml2015-result-buffer
 577              (buffer-string))))
 578         (progn
 579           (erase-buffer)
 580           ;; Treat data which pgg returns as a unibyte string.
 581           (mm-disable-multibyte)
 582           (insert-buffer-substring pgg-output-buffer)
 583           (goto-char (point-min))
 584           (while (search-forward "\r\n" nil t)
 585             (replace-match "\n" t t))
 586           (mm-set-handle-multipart-parameter
 587            mm-security-handle 'gnus-info "OK"))
 588       (mm-set-handle-multipart-parameter
 589        mm-security-handle 'gnus-info "Failed"))))
 590
 591 (defun mml2015-pgg-verify (handle ctl)
 592   (let ((pgg-errors-buffer mml2015-result-buffer)
 593         signature-file part signature)
 594     (if (or (null (setq part (mm-find-raw-part-by-type
 595                               ctl (or (mm-handle-multipart-ctl-parameter
 596                                        ctl 'protocol)
 597                                       "application/pgp-signature")
 598                               t)))
 599             (null (setq signature (mm-find-part-by-type
 600                                    (cdr handle) "application/pgp-signature" nil t))))
 601         (progn
 602           (mm-set-handle-multipart-parameter
 603            mm-security-handle 'gnus-info "Corrupted")
 604           handle)
 605       (with-temp-buffer
 606         (insert part)
 607         ;; Convert <LF> to <CR><LF> in signed text.  If --textmode is
 608         ;; specified when signing, the conversion is not necessary.
 609         (goto-char (point-min))
 610         (end-of-line)
 611         (while (not (eobp))
 612           (unless (eq (char-before) ?\r)
 613             (insert "\r"))
 614           (forward-line)
 615           (end-of-line))
 616         (with-temp-file (setq signature-file (mm-make-temp-file "pgg"))
 617           (mm-insert-part signature))
 618         (if (condition-case err
 619                 (prog1
 620                     (pgg-verify-region (point-min) (point-max)
 621                                        signature-file t)
 622                   (goto-char (point-min))
 623                   (while (search-forward "\r\n" nil t)
 624                     (replace-match "\n" t t))
 625                   (mm-set-handle-multipart-parameter
 626                    mm-security-handle 'gnus-details
 627                    (concat (with-current-buffer pgg-output-buffer
 628                              (buffer-string))
 629                            (with-current-buffer pgg-errors-buffer
 630                              (buffer-string)))))
 631               (error
 632                (mm-set-handle-multipart-parameter
 633                 mm-security-handle 'gnus-details (mml2015-format-error err))
 634                nil)
 635               (quit
 636                (mm-set-handle-multipart-parameter
 637                 mm-security-handle 'gnus-details "Quit.")
 638                nil))
 639             (progn
 640               (delete-file signature-file)
 641               (mm-set-handle-multipart-parameter
 642                mm-security-handle 'gnus-info
 643                (with-current-buffer pgg-errors-buffer
 644                  (mml2015-gpg-extract-signature-details))))
 645           (delete-file signature-file)
 646           (mm-set-handle-multipart-parameter
 647            mm-security-handle 'gnus-info "Failed")))))
 648   handle)
 649
 650 (defun mml2015-pgg-clear-verify ()
 651   (let ((pgg-errors-buffer mml2015-result-buffer)
 652         (text (buffer-string))
 653         (coding-system buffer-file-coding-system))
 654     (if (condition-case err
 655             (prog1
 656                 (mm-with-unibyte-buffer
 657                   (insert (mm-encode-coding-string text coding-system))
 658                   (pgg-verify-region (point-min) (point-max) nil t))
 659               (goto-char (point-min))
 660               (while (search-forward "\r\n" nil t)
 661                 (replace-match "\n" t t))
 662               (mm-set-handle-multipart-parameter
 663                mm-security-handle 'gnus-details
 664                (concat (with-current-buffer pgg-output-buffer
 665                          (buffer-string))
 666                        (with-current-buffer pgg-errors-buffer
 667                          (buffer-string)))))
 668           (error
 669            (mm-set-handle-multipart-parameter
 670             mm-security-handle 'gnus-details (mml2015-format-error err))
 671            nil)
 672           (quit
 673            (mm-set-handle-multipart-parameter
 674             mm-security-handle 'gnus-details "Quit.")
 675            nil))
 676         (mm-set-handle-multipart-parameter
 677          mm-security-handle 'gnus-info
 678          (with-current-buffer pgg-errors-buffer
 679            (mml2015-gpg-extract-signature-details)))
 680       (mm-set-handle-multipart-parameter
 681        mm-security-handle 'gnus-info "Failed")))
 682   (mml2015-extract-cleartext-signature))
 683
 684 (defun mml2015-pgg-sign (cont)
 685   (let ((pgg-errors-buffer mml2015-result-buffer)
 686         (boundary (mml-compute-boundary cont))
 687         (pgg-default-user-id (or (message-options-get 'mml-sender)
 688                                  pgg-default-user-id))
 689         (pgg-text-mode t)
 690         entry)
 691     (unless (pgg-sign-region (point-min) (point-max))
 692       (pop-to-buffer mml2015-result-buffer)
 693       (error "Sign error"))
 694     (goto-char (point-min))
 695     (insert (format "Content-Type: multipart/signed; boundary=\"%s\";\n"
 696                     boundary))
 697     (if (setq entry (assq 2 (pgg-parse-armor
 698                              (with-current-buffer pgg-output-buffer
 699                                (buffer-string)))))
 700         (setq entry (assq 'hash-algorithm (cdr entry))))
 701     (insert (format "\tmicalg=%s; "
 702                     (if (cdr entry)
 703                         (downcase (format "pgp-%s" (cdr entry)))
 704                       "pgp-sha1")))
 705     (insert "protocol=\"application/pgp-signature\"\n")
 706     (insert (format "\n--%s\n" boundary))
 707     (goto-char (point-max))
 708     (insert (format "\n--%s\n" boundary))
 709     (insert "Content-Type: application/pgp-signature\n\n")
 710     (insert-buffer-substring pgg-output-buffer)
 711     (goto-char (point-max))
 712     (insert (format "--%s--\n" boundary))
 713     (goto-char (point-max))))
 714
 715 (defun mml2015-pgg-encrypt (cont &optional sign)
 716   (let ((pgg-errors-buffer mml2015-result-buffer)
 717         (pgg-text-mode t)
 718         (boundary (mml-compute-boundary cont)))
 719     (unless (pgg-encrypt-region (point-min) (point-max)
 720                                 (split-string
 721                                  (or
 722                                   (message-options-get 'message-recipients)
 723                                   (message-options-set 'message-recipients
 724                                                        (read-string "Recipients: ")))
 725                                  "[ \f\t\n\r\v,]+")
 726                                 sign)
 727       (pop-to-buffer mml2015-result-buffer)
 728       (error "Encrypt error"))
 729     (delete-region (point-min) (point-max))
 730     (goto-char (point-min))
 731     (insert (format "Content-Type: multipart/encrypted; boundary=\"%s\";\n"
 732                     boundary))
 733     (insert "\tprotocol=\"application/pgp-encrypted\"\n\n")
 734     (insert (format "--%s\n" boundary))
 735     (insert "Content-Type: application/pgp-encrypted\n\n")
 736     (insert "Version: 1\n\n")
 737     (insert (format "--%s\n" boundary))
 738     (insert "Content-Type: application/octet-stream\n\n")
 739     (insert-buffer-substring pgg-output-buffer)
 740     (goto-char (point-max))
 741     (insert (format "--%s--\n" boundary))
 742     (goto-char (point-max))))
 743
 744 ;;; epg wrapper
 745
 746 (defvar epg-user-id-alist)
 747 (defvar epg-digest-algorithm-alist)
 748 (defvar epg-gpg-program)
 749 (defvar inhibit-redisplay)
 750
 751 (autoload 'epg-make-context "epg")
 752 (autoload 'epg-context-set-armor "epg")
 753 (autoload 'epg-context-set-textmode "epg")
 754 (autoload 'epg-context-set-signers "epg")
 755 (autoload 'epg-context-result-for "epg")
 756 (autoload 'epg-new-signature-digest-algorithm "epg")
 757 (autoload 'epg-list-keys "epg")
 758 (autoload 'epg-decrypt-string "epg")
 759 (autoload 'epg-verify-string "epg")
 760 (autoload 'epg-sign-string "epg")
 761 (autoload 'epg-encrypt-string "epg")
 762 (autoload 'epg-passphrase-callback-function "epg")
 763 (autoload 'epg-context-set-passphrase-callback "epg")
 764 (autoload 'epg-key-sub-key-list "epg")
 765 (autoload 'epg-sub-key-capability "epg")
 766 (autoload 'epg-sub-key-validity "epg")
 767 (autoload 'epg-sub-key-fingerprint "epg")
 768 (autoload 'epg-signature-key-id "epg")
 769 (autoload 'epg-signature-to-string "epg")
 770 (autoload 'epg-key-user-id-list "epg")
 771 (autoload 'epg-user-id-string "epg")
 772 (autoload 'epg-user-id-validity "epg")
 773 (autoload 'epg-configuration "epg-config")
 774 (autoload 'epg-expand-group "epg-config")
 775 (autoload 'epa-select-keys "epa")
 776
 777 (defvar mml2015-epg-secret-key-id-list nil)
 778
 779 (defun mml2015-epg-passphrase-callback (context key-id ignore)
 780   (if (eq key-id 'SYM)
 781       (epg-passphrase-callback-function context key-id nil)
 782     (let* ((password-cache-key-id
 783             (if (eq key-id 'PIN)
 784                 "PIN"
 785                key-id))
 786            entry
 787            (passphrase
 788             (password-read
 789              (if (eq key-id 'PIN)
 790                  "Passphrase for PIN: "
 791                (if (setq entry (assoc key-id epg-user-id-alist))
 792                    (format "Passphrase for %s %s: " key-id (cdr entry))
 793                  (format "Passphrase for %s: " key-id)))
 794              password-cache-key-id)))
 795       (when passphrase
 796         (let ((password-cache-expiry mml2015-passphrase-cache-expiry))
 797           (password-cache-add password-cache-key-id passphrase))
 798         (setq mml2015-epg-secret-key-id-list
 799               (cons password-cache-key-id mml2015-epg-secret-key-id-list))
 800         (copy-sequence passphrase)))))
 801
 802 (defun mml2015-epg-check-user-id (key recipient)
 803   (let ((pointer (epg-key-user-id-list key))
 804         result)
 805     (while pointer
 806       (if (and (equal (car (mail-header-parse-address
 807                             (epg-user-id-string (car pointer))))
 808                       (car (mail-header-parse-address
 809                             recipient)))
 810                (not (memq (epg-user-id-validity (car pointer))
 811                           '(revoked expired))))
 812           (setq result t
 813                 pointer nil)
 814         (setq pointer (cdr pointer))))
 815     result))
 816
 817 (defun mml2015-epg-check-sub-key (key usage)
 818   (let ((pointer (epg-key-sub-key-list key))
 819         result)
 820     ;; The primary key will be marked as disabled, when the entire
 821     ;; key is disabled (see 12 Field, Format of colon listings, in
 822     ;; gnupg/doc/DETAILS)
 823     (unless (memq 'disabled (epg-sub-key-capability (car pointer)))
 824       (while pointer
 825         (if (and (memq usage (epg-sub-key-capability (car pointer)))
 826                  (not (memq (epg-sub-key-validity (car pointer))
 827                             '(revoked expired))))
 828             (setq result t
 829                   pointer nil)
 830           (setq pointer (cdr pointer)))))
 831     result))
 832
 833 (defun mml2015-epg-find-usable-key (context name usage
 834                                             &optional name-is-key-id)
 835   (let ((keys (epg-list-keys context name))
 836         key)
 837     (while keys
 838       (if (and (or name-is-key-id
 839                    ;; Non email user-id can be supplied through
 840                    ;; mml2015-signers if mml2015-encrypt-to-self is set.
 841                    ;; Treat it as valid, as it is user's intention.
 842                    (not (string-match "\\`<" name))
 843                    (mml2015-epg-check-user-id (car keys) name))
 844                (mml2015-epg-check-sub-key (car keys) usage))
 845           (setq key (car keys)
 846                 keys nil)
 847         (setq keys (cdr keys))))
 848     key))
 849
 850 ;; XXX: since gpg --list-secret-keys does not return validity of each
 851 ;; key, `mml2015-epg-find-usable-key' defined above is not enough for
 852 ;; secret keys.  The function `mml2015-epg-find-usable-secret-key'
 853 ;; below looks at appropriate public keys to check usability.
 854 (defun mml2015-epg-find-usable-secret-key (context name usage)
 855   (let ((secret-keys (epg-list-keys context name t))
 856         secret-key)
 857     (while (and (not secret-key) secret-keys)
 858       (if (mml2015-epg-find-usable-key
 859            context
 860            (epg-sub-key-fingerprint
 861             (car (epg-key-sub-key-list
 862                   (car secret-keys))))
 863            usage
 864            t)
 865           (setq secret-key (car secret-keys)
 866                 secret-keys nil)
 867         (setq secret-keys (cdr secret-keys))))
 868     secret-key))
 869
 870 (autoload 'gnus-create-image "gnus-ems")
 871
 872 (defun mml2015-epg-key-image (key-id)
 873   "Return the image of a key, if any"
 874   (with-temp-buffer
 875     (mm-set-buffer-multibyte nil)
 876     (let* ((coding-system-for-write 'binary)
 877            (coding-system-for-read 'binary)
 878            (data (shell-command-to-string
 879                   (format "%s --list-options no-show-photos --attribute-fd 3 --list-keys %s 3>&1 >/dev/null 2>&1"
 880                           (shell-quote-argument epg-gpg-program) key-id))))
 881       (when (> (length data) 0)
 882         (insert (substring data 16))
 883         (condition-case nil
 884             (gnus-create-image (buffer-string) nil t)
 885           (error))))))
 886
 887 (autoload 'gnus-rescale-image "gnus-util")
 888
 889 (defun mml2015-epg-key-image-to-string (key-id)
 890   "Return a string with the image of a key, if any"
 891   (let ((key-image (mml2015-epg-key-image key-id)))
 892     (if (not key-image)
 893         ""
 894       (condition-case error
 895           (let ((result "  "))
 896             (put-text-property
 897              1 2 'display
 898              (gnus-rescale-image key-image
 899                                  (cons mml2015-maximum-key-image-dimension
 900                                        mml2015-maximum-key-image-dimension))
 901              result)
 902             result)
 903         (error "")))))
 904
 905 (defun mml2015-epg-signature-to-string (signature)
 906   (concat (epg-signature-to-string signature)
 907           (when mml2015-display-key-image
 908             (mml2015-epg-key-image-to-string (epg-signature-key-id signature)))))
 909
 910 (defun mml2015-epg-verify-result-to-string (verify-result)
 911   (mapconcat #'mml2015-epg-signature-to-string verify-result "\n"))
 912
 913 (defun mml2015-epg-decrypt (handle ctl)
 914   (catch 'error
 915     (let ((inhibit-redisplay t)
 916           context plain child handles result decrypt-status)
 917       (unless (setq child (mm-find-part-by-type
 918                            (cdr handle)
 919                            "application/octet-stream" nil t))
 920         (mm-set-handle-multipart-parameter
 921          mm-security-handle 'gnus-info "Corrupted")
 922         (throw 'error handle))
 923       (setq context (epg-make-context))
 924       (if mml2015-cache-passphrase
 925           (epg-context-set-passphrase-callback
 926            context
 927            #'mml2015-epg-passphrase-callback))
 928       (condition-case error
 929           (setq plain (epg-decrypt-string context (mm-get-part child))
 930                 mml2015-epg-secret-key-id-list nil)
 931         (error
 932          (while mml2015-epg-secret-key-id-list
 933            (password-cache-remove (car mml2015-epg-secret-key-id-list))
 934            (setq mml2015-epg-secret-key-id-list
 935                  (cdr mml2015-epg-secret-key-id-list)))
 936          (mm-set-handle-multipart-parameter
 937           mm-security-handle 'gnus-info "Failed")
 938          (if (eq (car error) 'quit)
 939              (mm-set-handle-multipart-parameter
 940               mm-security-handle 'gnus-details "Quit.")
 941            (mm-set-handle-multipart-parameter
 942             mm-security-handle 'gnus-details (mml2015-format-error error)))
 943          (throw 'error handle)))
 944       (with-temp-buffer
 945         (insert plain)
 946         (goto-char (point-min))
 947         (while (search-forward "\r\n" nil t)
 948           (replace-match "\n" t t))
 949         (setq handles (mm-dissect-buffer t))
 950         (mm-destroy-parts handle)
 951         (if (epg-context-result-for context 'verify)
 952             (mm-set-handle-multipart-parameter
 953              mm-security-handle 'gnus-info
 954              (concat "OK\n"
 955                      (mml2015-epg-verify-result-to-string
 956                       (epg-context-result-for context 'verify))))
 957           (mm-set-handle-multipart-parameter
 958            mm-security-handle 'gnus-info "OK"))
 959         (if (stringp (car handles))
 960             (mm-set-handle-multipart-parameter
 961              mm-security-handle 'gnus-details
 962              (mm-handle-multipart-ctl-parameter handles 'gnus-details))))
 963         (if (listp (car handles))
 964             handles
 965           (list handles)))))
 966
 967 (defun mml2015-epg-clear-decrypt ()
 968   (let ((inhibit-redisplay t)
 969         (context (epg-make-context))
 970         plain)
 971     (if mml2015-cache-passphrase
 972         (epg-context-set-passphrase-callback
 973          context
 974          #'mml2015-epg-passphrase-callback))
 975     (condition-case error
 976         (setq plain (epg-decrypt-string context (buffer-string))
 977               mml2015-epg-secret-key-id-list nil)
 978       (error
 979        (while mml2015-epg-secret-key-id-list
 980          (password-cache-remove (car mml2015-epg-secret-key-id-list))
 981          (setq mml2015-epg-secret-key-id-list
 982                (cdr mml2015-epg-secret-key-id-list)))
 983        (mm-set-handle-multipart-parameter
 984         mm-security-handle 'gnus-info "Failed")
 985        (if (eq (car error) 'quit)
 986            (mm-set-handle-multipart-parameter
 987             mm-security-handle 'gnus-details "Quit.")
 988          (mm-set-handle-multipart-parameter
 989           mm-security-handle 'gnus-details (mml2015-format-error error)))))
 990     (when plain
 991       (erase-buffer)
 992       ;; Treat data which epg returns as a unibyte string.
 993       (mm-disable-multibyte)
 994       (insert plain)
 995       (goto-char (point-min))
 996       (while (search-forward "\r\n" nil t)
 997         (replace-match "\n" t t))
 998       (mm-set-handle-multipart-parameter
 999        mm-security-handle 'gnus-info "OK")
1000       (if (epg-context-result-for context 'verify)
1001           (mm-set-handle-multipart-parameter
1002            mm-security-handle 'gnus-details
1003            (mml2015-epg-verify-result-to-string
1004             (epg-context-result-for context 'verify)))))))
1005
1006 (defun mml2015-epg-verify (handle ctl)
1007   (catch 'error
1008     (let ((inhibit-redisplay t)
1009           context plain signature-file part signature)
1010       (when (or (null (setq part (mm-find-raw-part-by-type
1011                                   ctl (or (mm-handle-multipart-ctl-parameter
1012                                            ctl 'protocol)
1013                                           "application/pgp-signature")
1014                                   t)))
1015                 (null (setq signature (mm-find-part-by-type
1016                                        (cdr handle) "application/pgp-signature"
1017                                        nil t))))
1018         (mm-set-handle-multipart-parameter
1019          mm-security-handle 'gnus-info "Corrupted")
1020         (throw 'error handle))
1021       (setq part (mm-replace-in-string part "\n" "\r\n")
1022             signature (mm-get-part signature)
1023             context (epg-make-context))
1024       (condition-case error
1025           (setq plain (epg-verify-string context signature part))
1026         (error
1027          (mm-set-handle-multipart-parameter
1028           mm-security-handle 'gnus-info "Failed")
1029          (if (eq (car error) 'quit)
1030              (mm-set-handle-multipart-parameter
1031               mm-security-handle 'gnus-details "Quit.")
1032            (mm-set-handle-multipart-parameter
1033             mm-security-handle 'gnus-details (mml2015-format-error error)))
1034          (throw 'error handle)))
1035       (mm-set-handle-multipart-parameter
1036        mm-security-handle 'gnus-info
1037        (mml2015-epg-verify-result-to-string
1038         (epg-context-result-for context 'verify)))
1039       handle)))
1040
1041 (defun mml2015-epg-clear-verify ()
1042   (let ((inhibit-redisplay t)
1043         (context (epg-make-context))
1044         (signature (mm-encode-coding-string (buffer-string)
1045                                             coding-system-for-write))
1046         plain)
1047     (condition-case error
1048         (setq plain (epg-verify-string context signature))
1049       (error
1050        (mm-set-handle-multipart-parameter
1051         mm-security-handle 'gnus-info "Failed")
1052        (if (eq (car error) 'quit)
1053            (mm-set-handle-multipart-parameter
1054             mm-security-handle 'gnus-details "Quit.")
1055          (mm-set-handle-multipart-parameter
1056           mm-security-handle 'gnus-details (mml2015-format-error error)))))
1057     (if plain
1058         (progn
1059           (mm-set-handle-multipart-parameter
1060            mm-security-handle 'gnus-info
1061            (mml2015-epg-verify-result-to-string
1062             (epg-context-result-for context 'verify)))
1063           (delete-region (point-min) (point-max))
1064           (insert (mm-decode-coding-string plain coding-system-for-read)))
1065       (mml2015-extract-cleartext-signature))))
1066
1067 (defun mml2015-epg-sign (cont)
1068   (let* ((inhibit-redisplay t)
1069          (context (epg-make-context))
1070          (boundary (mml-compute-boundary cont))
1071          (sender (message-options-get 'message-sender))
1072          (signer-names (or mml2015-signers
1073                            (if (and mml2015-sign-with-sender sender)
1074                                (list (concat "<" sender ">")))))
1075          signer-key
1076          (signers
1077           (or (message-options-get 'mml2015-epg-signers)
1078               (message-options-set
1079                'mml2015-epg-signers
1080                (if (eq mm-sign-option 'guided)
1081                    (epa-select-keys context "\
1082 Select keys for signing.
1083 If no one is selected, default secret key is used.  "
1084                                     signer-names
1085                                     t)
1086                  (if (or sender mml2015-signers)
1087                      (delq nil
1088                            (mapcar
1089                             (lambda (signer)
1090                               (setq signer-key
1091                                     (mml2015-epg-find-usable-secret-key
1092                                      context signer 'sign))
1093                               (unless (or signer-key
1094                                           (y-or-n-p
1095                                            (format
1096                                             "No secret key for %s; skip it? "
1097                                             signer)))
1098                                 (error "No secret key for %s" signer))
1099                               signer-key)
1100                             signer-names)))))))
1101          signature micalg)
1102     (epg-context-set-armor context t)
1103     (epg-context-set-textmode context t)
1104     (epg-context-set-signers context signers)
1105     (if mml2015-cache-passphrase
1106         (epg-context-set-passphrase-callback
1107          context
1108          #'mml2015-epg-passphrase-callback))
1109     ;; Signed data must end with a newline (RFC 3156, 5).
1110     (goto-char (point-max))
1111     (unless (bolp)
1112       (insert "\n"))
1113     (condition-case error
1114         (setq signature (epg-sign-string context (buffer-string) t)
1115               mml2015-epg-secret-key-id-list nil)
1116       (error
1117        (while mml2015-epg-secret-key-id-list
1118          (password-cache-remove (car mml2015-epg-secret-key-id-list))
1119          (setq mml2015-epg-secret-key-id-list
1120                (cdr mml2015-epg-secret-key-id-list)))
1121        (signal (car error) (cdr error))))
1122     (if (epg-context-result-for context 'sign)
1123         (setq micalg (epg-new-signature-digest-algorithm
1124                       (car (epg-context-result-for context 'sign)))))
1125     (goto-char (point-min))
1126     (insert (format "Content-Type: multipart/signed; boundary=\"%s\";\n"
1127                     boundary))
1128     (if micalg
1129         (insert (format "\tmicalg=pgp-%s; "
1130                         (downcase
1131                          (cdr (assq micalg
1132                                     epg-digest-algorithm-alist))))))
1133     (insert "protocol=\"application/pgp-signature\"\n")
1134     (insert (format "\n--%s\n" boundary))
1135     (goto-char (point-max))
1136     (insert (format "\n--%s\n" boundary))
1137     (insert "Content-Type: application/pgp-signature; name=\"signature.asc\"\n\n")
1138     (insert signature)
1139     (goto-char (point-max))
1140     (insert (format "--%s--\n" boundary))
1141     (goto-char (point-max))))
1142
1143 (defun mml2015-epg-encrypt (cont &optional sign)
1144   (let* ((inhibit-redisplay t)
1145          (context (epg-make-context))
1146          (boundary (mml-compute-boundary cont))
1147          (config (epg-configuration))
1148          (recipients (message-options-get 'mml2015-epg-recipients))
1149          cipher
1150          (sender (message-options-get 'message-sender))
1151          (signer-names (or mml2015-signers
1152                            (if (and mml2015-sign-with-sender sender)
1153                                (list (concat "<" sender ">")))))
1154          signers
1155          recipient-key signer-key)
1156     (unless recipients
1157       (setq recipients
1158             (apply #'nconc
1159                    (mapcar
1160                     (lambda (recipient)
1161                       (or (epg-expand-group config recipient)
1162                           (list (concat "<" recipient ">"))))
1163                     (split-string
1164                      (or (message-options-get 'message-recipients)
1165                          (message-options-set 'message-recipients
1166                                               (read-string "Recipients: ")))
1167                      "[ \f\t\n\r\v,]+"))))
1168       (when mml2015-encrypt-to-self
1169         (unless signer-names
1170           (error "Neither message sender nor mml2015-signers are set"))
1171         (setq recipients (nconc recipients signer-names)))
1172       (if (eq mm-encrypt-option 'guided)
1173           (setq recipients
1174                 (epa-select-keys context "\
1175 Select recipients for encryption.
1176 If no one is selected, symmetric encryption will be performed.  "
1177                                  recipients))
1178         (setq recipients
1179               (delq nil
1180                     (mapcar
1181                      (lambda (recipient)
1182                        (setq recipient-key (mml2015-epg-find-usable-key
1183                                             context recipient 'encrypt))
1184                        (unless (or recipient-key
1185                                    (y-or-n-p
1186                                     (format "No public key for %s; skip it? "
1187                                             recipient)))
1188                          (error "No public key for %s" recipient))
1189                        recipient-key)
1190                      recipients)))
1191         (unless recipients
1192           (error "No recipient specified")))
1193       (message-options-set 'mml2015-epg-recipients recipients))
1194     (when sign
1195       (setq signers
1196             (or (message-options-get 'mml2015-epg-signers)
1197                 (message-options-set
1198                  'mml2015-epg-signers
1199                  (if (eq mm-sign-option 'guided)
1200                      (epa-select-keys context "\
1201 Select keys for signing.
1202 If no one is selected, default secret key is used.  "
1203                                       signer-names
1204                                       t)
1205                    (if (or sender mml2015-signers)
1206                        (delq nil
1207                              (mapcar
1208                               (lambda (signer)
1209                                 (setq signer-key
1210                                       (mml2015-epg-find-usable-secret-key
1211                                        context signer 'sign))
1212                                 (unless (or signer-key
1213                                             (y-or-n-p
1214                                              (format
1215                                               "No secret key for %s; skip it? "
1216                                               signer)))
1217                                   (error "No secret key for %s" signer))
1218                                 signer-key)
1219                               signer-names)))))))
1220       (epg-context-set-signers context signers))
1221     (epg-context-set-armor context t)
1222     (epg-context-set-textmode context t)
1223     (if mml2015-cache-passphrase
1224         (epg-context-set-passphrase-callback
1225          context
1226          #'mml2015-epg-passphrase-callback))
1227     (condition-case error
1228         (setq cipher
1229               (epg-encrypt-string context (buffer-string) recipients sign
1230                                   mml2015-always-trust)
1231               mml2015-epg-secret-key-id-list nil)
1232       (error
1233        (while mml2015-epg-secret-key-id-list
1234          (password-cache-remove (car mml2015-epg-secret-key-id-list))
1235          (setq mml2015-epg-secret-key-id-list
1236                (cdr mml2015-epg-secret-key-id-list)))
1237        (signal (car error) (cdr error))))
1238     (delete-region (point-min) (point-max))
1239     (goto-char (point-min))
1240     (insert (format "Content-Type: multipart/encrypted; boundary=\"%s\";\n"
1241                     boundary))
1242     (insert "\tprotocol=\"application/pgp-encrypted\"\n\n")
1243     (insert (format "--%s\n" boundary))
1244     (insert "Content-Type: application/pgp-encrypted\n\n")
1245     (insert "Version: 1\n\n")
1246     (insert (format "--%s\n" boundary))
1247     (insert "Content-Type: application/octet-stream\n\n")
1248     (insert cipher)
1249     (goto-char (point-max))
1250     (insert (format "--%s--\n" boundary))
1251     (goto-char (point-max))))
1252
1253 ;;; General wrapper
1254
1255 (autoload 'gnus-buffer-live-p "gnus-util")
1256 (autoload 'gnus-get-buffer-create "gnus")
1257
1258 (defun mml2015-clean-buffer ()
1259   (if (gnus-buffer-live-p mml2015-result-buffer)
1260       (with-current-buffer mml2015-result-buffer
1261         (erase-buffer)
1262         t)
1263     (setq mml2015-result-buffer
1264           (gnus-get-buffer-create " *MML2015 Result*"))
1265     nil))
1266
1267 (defsubst mml2015-clear-decrypt-function ()
1268   (nth 6 (assq mml2015-use mml2015-function-alist)))
1269
1270 (defsubst mml2015-clear-verify-function ()
1271   (nth 5 (assq mml2015-use mml2015-function-alist)))
1272
1273 ;;;###autoload
1274 (defun mml2015-decrypt (handle ctl)
1275   (mml2015-clean-buffer)
1276   (let ((func (nth 4 (assq mml2015-use mml2015-function-alist))))
1277     (if func
1278         (funcall func handle ctl)
1279       handle)))
1280
1281 ;;;###autoload
1282 (defun mml2015-decrypt-test (handle ctl)
1283   mml2015-use)
1284
1285 ;;;###autoload
1286 (defun mml2015-verify (handle ctl)
1287   (mml2015-clean-buffer)
1288   (let ((func (nth 3 (assq mml2015-use mml2015-function-alist))))
1289     (if func
1290         (funcall func handle ctl)
1291       handle)))
1292
1293 ;;;###autoload
1294 (defun mml2015-verify-test (handle ctl)
1295   mml2015-use)
1296
1297 ;;;###autoload
1298 (defun mml2015-encrypt (cont &optional sign)
1299   (mml2015-clean-buffer)
1300   (let ((func (nth 2 (assq mml2015-use mml2015-function-alist))))
1301     (if func
1302         (funcall func cont sign)
1303       (error "Cannot find encrypt function"))))
1304
1305 ;;;###autoload
1306 (defun mml2015-sign (cont)
1307   (mml2015-clean-buffer)
1308   (let ((func (nth 1 (assq mml2015-use mml2015-function-alist))))
1309     (if func
1310         (funcall func cont)
1311       (error "Cannot find sign function"))))
1312
1313 ;;;###autoload
1314 (defun mml2015-self-encrypt ()
1315   (mml2015-encrypt nil))
1316
1317 (provide 'mml2015)
1318
1319 ;;; mml2015.el ends here