lisp/gnus/mml2015.el

   1 ;;; mml2015.el --- MIME Security with Pretty Good Privacy (PGP)
   2
   3 ;; Copyright (C) 2000-2014 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 ;; Maybe this should be in eg mml-sec.el (and have a different name).
  51 ;; Then mml1991 would not need to require mml2015, and mml1991-use
  52 ;; could be removed.
  53 (defvar mml2015-use (or
  54                      (condition-case nil
  55                          (progn
  56                            (require 'epg-config)
  57                            (epg-check-configuration (epg-configuration))
  58                            'epg)
  59                        (error))
  60                      (progn
  61                        (let ((abs-file (locate-library "pgg")))
  62                          ;; Don't load PGG if it is marked as obsolete
  63                          ;; (Emacs 24).
  64                          (when (and abs-file
  65                                     (not (string-match "/obsolete/[^/]*\\'"
  66                                                        abs-file)))
  67                            (ignore-errors (require 'pgg))
  68                            (and (fboundp 'pgg-sign-region)
  69                                 'pgg))))
  70                      (progn (ignore-errors
  71                               (load "mc-toplev"))
  72                             (and (fboundp 'mc-encrypt-generic)
  73                                  (fboundp 'mc-sign-generic)
  74                                  (fboundp 'mc-cleanup-recipient-headers)
  75                                  'mailcrypt)))
  76   "The package used for PGP/MIME.
  77 Valid packages include `epg', `pgg' and `mailcrypt'.")
  78
  79 ;; Something is not RFC2015.
  80 (defvar mml2015-function-alist
  81   '((mailcrypt mml2015-mailcrypt-sign
  82                mml2015-mailcrypt-encrypt
  83                mml2015-mailcrypt-verify
  84                mml2015-mailcrypt-decrypt
  85                mml2015-mailcrypt-clear-verify
  86                mml2015-mailcrypt-clear-decrypt)
  87     (pgg mml2015-pgg-sign
  88          mml2015-pgg-encrypt
  89          mml2015-pgg-verify
  90          mml2015-pgg-decrypt
  91          mml2015-pgg-clear-verify
  92          mml2015-pgg-clear-decrypt)
  93     (epg mml2015-epg-sign
  94          mml2015-epg-encrypt
  95          mml2015-epg-verify
  96          mml2015-epg-decrypt
  97          mml2015-epg-clear-verify
  98          mml2015-epg-clear-decrypt))
  99   "Alist of PGP/MIME functions.")
 100
 101 (defvar mml2015-result-buffer nil)
 102
 103 (defcustom mml2015-unabbrev-trust-alist
 104   '(("TRUST_UNDEFINED" . nil)
 105     ("TRUST_NEVER"     . nil)
 106     ("TRUST_MARGINAL"  . t)
 107     ("TRUST_FULLY"     . t)
 108     ("TRUST_ULTIMATE"  . t))
 109   "Map GnuPG trust output values to a boolean saying if you trust the key."
 110   :version "22.1"
 111   :group 'mime-security
 112   :type '(repeat (cons (regexp :tag "GnuPG output regexp")
 113                        (boolean :tag "Trust key"))))
 114
 115 (defcustom mml2015-cache-passphrase mml-secure-cache-passphrase
 116   "If t, cache passphrase."
 117   :group 'mime-security
 118   :type 'boolean)
 119
 120 (defcustom mml2015-passphrase-cache-expiry mml-secure-passphrase-cache-expiry
 121   "How many seconds the passphrase is cached.
 122 Whether the passphrase is cached at all is controlled by
 123 `mml2015-cache-passphrase'."
 124   :group 'mime-security
 125   :type 'integer)
 126
 127 (defcustom mml2015-signers nil
 128   "A list of your own key ID(s) which will be used to sign a message.
 129 If set, it overrides the setting of `mml2015-sign-with-sender'."
 130   :group 'mime-security
 131   :type '(repeat (string :tag "Key ID")))
 132
 133 (defcustom mml2015-sign-with-sender nil
 134   "If t, use message sender so find a key to sign with."
 135   :group 'mime-security
 136   :type 'boolean
 137   :version "24.1")
 138
 139 (defcustom mml2015-encrypt-to-self nil
 140   "If t, add your own key ID to recipient list when encryption."
 141   :group 'mime-security
 142   :type 'boolean)
 143
 144 (defcustom mml2015-always-trust t
 145   "If t, GnuPG skip key validation on encryption."
 146   :group 'mime-security
 147   :type 'boolean)
 148
 149 (defcustom mml2015-maximum-key-image-dimension 64
 150   "The maximum dimension (width or height) of any key images."
 151   :version "24.4"
 152   :group 'mime-security
 153   :type 'integer)
 154
 155 ;; Extract plaintext from cleartext signature.  IMO, this kind of task
 156 ;; should be done by GnuPG rather than Elisp, but older PGP backends
 157 ;; (such as Mailcrypt, and PGG) discard the output from GnuPG.
 158 (defun mml2015-extract-cleartext-signature ()
 159   ;; Daiki Ueno in
 160   ;; <54a15d860801080142l70b95d7dkac4bf51a86196011@mail.gmail.com>: ``I still
 161   ;; believe that the right way is to use the plaintext output from GnuPG as
 162   ;; it is, and mml2015-extract-cleartext-signature is just a kludge for
 163   ;; misdesigned libraries like PGG, which have no ability to do that.  So, I
 164   ;; think it should not have descriptive documentation.''
 165   ;;
 166   ;; This function doesn't handle NotDashEscaped correctly.  EasyPG handles it
 167   ;; correctly.
 168   ;; http://thread.gmane.org/gmane.emacs.gnus.general/66062/focus=66082
 169   ;; http://thread.gmane.org/gmane.emacs.gnus.general/65087/focus=65109
 170   (goto-char (point-min))
 171   (forward-line)
 172   ;; We need to be careful not to strip beyond the armor headers.
 173   ;; Previously, an attacker could replace the text inside our
 174   ;; markup with trailing garbage by injecting whitespace into the
 175   ;; message.
 176   (while (looking-at "Hash:")           ; The only header allowed in cleartext
 177     (forward-line))                     ; signatures according to RFC2440.
 178   (when (looking-at "[\t ]*$")
 179     (forward-line))
 180   (delete-region (point-min) (point))
 181   (if (re-search-forward "^-----BEGIN PGP SIGNATURE-----" nil t)
 182       (delete-region (match-beginning 0) (point-max)))
 183   (goto-char (point-min))
 184   (while (re-search-forward "^- " nil t)
 185     (replace-match "" t t)
 186     (forward-line 1)))
 187
 188 ;;; mailcrypt wrapper
 189
 190 (autoload 'mailcrypt-decrypt "mailcrypt")
 191 (autoload 'mailcrypt-verify "mailcrypt")
 192 (autoload 'mc-pgp-always-sign "mailcrypt")
 193 (autoload 'mc-encrypt-generic "mc-toplev")
 194 (autoload 'mc-cleanup-recipient-headers "mc-toplev")
 195 (autoload 'mc-sign-generic "mc-toplev")
 196
 197 (defvar mml2015-decrypt-function 'mailcrypt-decrypt)
 198 (defvar mml2015-verify-function 'mailcrypt-verify)
 199
 200 (defun mml2015-format-error (err)
 201   (if (stringp (cadr err))
 202       (cadr err)
 203     (format "%S" (cdr err))))
 204
 205 (defun mml2015-mailcrypt-decrypt (handle ctl)
 206   (catch 'error
 207     (let (child handles result)
 208       (unless (setq child (mm-find-part-by-type
 209                            (cdr handle)
 210                            "application/octet-stream" nil t))
 211         (mm-set-handle-multipart-parameter
 212          mm-security-handle 'gnus-info "Corrupted")
 213         (throw 'error handle))
 214       (with-temp-buffer
 215         (mm-insert-part child)
 216         (setq result
 217               (condition-case err
 218                   (funcall mml2015-decrypt-function)
 219                 (error
 220                  (mm-set-handle-multipart-parameter
 221                   mm-security-handle 'gnus-details (mml2015-format-error err))
 222                  nil)
 223                 (quit
 224                  (mm-set-handle-multipart-parameter
 225                   mm-security-handle 'gnus-details "Quit.")
 226                  nil)))
 227         (unless (car result)
 228           (mm-set-handle-multipart-parameter
 229            mm-security-handle 'gnus-info "Failed")
 230           (throw 'error handle))
 231         (setq handles (mm-dissect-buffer t)))
 232       (mm-destroy-parts handle)
 233       (mm-set-handle-multipart-parameter
 234        mm-security-handle 'gnus-info
 235        (concat "OK"
 236                (let ((sig (with-current-buffer mml2015-result-buffer
 237                             (mml2015-gpg-extract-signature-details))))
 238                  (concat ", Signer: " sig))))
 239       (if (listp (car handles))
 240           handles
 241         (list handles)))))
 242
 243 (defun mml2015-gpg-pretty-print-fpr (fingerprint)
 244   (let* ((result "")
 245          (fpr-length (string-width fingerprint))
 246          (n-slice 0)
 247          slice)
 248     (setq fingerprint (string-to-list fingerprint))
 249     (while fingerprint
 250       (setq fpr-length (- fpr-length 4))
 251       (setq slice (butlast fingerprint fpr-length))
 252       (setq fingerprint (nthcdr 4 fingerprint))
 253       (setq n-slice (1+ n-slice))
 254       (setq result
 255             (concat
 256              result
 257              (case n-slice
 258                (1  slice)
 259                (otherwise (concat " " slice))))))
 260     result))
 261
 262 (defun mml2015-gpg-extract-signature-details ()
 263   (goto-char (point-min))
 264   (let* ((expired (re-search-forward
 265                    "^\\[GNUPG:\\] SIGEXPIRED$"
 266                    nil t))
 267          (signer (and (re-search-forward
 268                        "^\\[GNUPG:\\] GOODSIG \\([0-9A-Za-z]*\\) \\(.*\\)$"
 269                        nil t)
 270                       (cons (match-string 1) (match-string 2))))
 271          (fprint (and (re-search-forward
 272                        "^\\[GNUPG:\\] VALIDSIG \\([0-9a-zA-Z]*\\) "
 273                        nil t)
 274                       (match-string 1)))
 275          (trust  (and (re-search-forward
 276                        "^\\[GNUPG:\\] \\(TRUST_.*\\)$"
 277                        nil t)
 278                       (match-string 1)))
 279          (trust-good-enough-p
 280           (cdr (assoc trust mml2015-unabbrev-trust-alist))))
 281     (cond ((and signer fprint)
 282            (concat (cdr signer)
 283                    (unless trust-good-enough-p
 284                      (concat "\nUntrusted, Fingerprint: "
 285                              (mml2015-gpg-pretty-print-fpr fprint)))
 286                    (when expired
 287                      (format "\nWARNING: Signature from expired key (%s)"
 288                              (car signer)))))
 289           ((re-search-forward
 290             "^\\(gpg: \\)?Good signature from \"\\(.*\\)\"$" nil t)
 291            (match-string 2))
 292           (t
 293            "From unknown user"))))
 294
 295 (defun mml2015-mailcrypt-clear-decrypt ()
 296   (let (result)
 297     (setq result
 298           (condition-case err
 299               (funcall mml2015-decrypt-function)
 300             (error
 301              (mm-set-handle-multipart-parameter
 302               mm-security-handle 'gnus-details (mml2015-format-error err))
 303              nil)
 304             (quit
 305              (mm-set-handle-multipart-parameter
 306               mm-security-handle 'gnus-details "Quit.")
 307              nil)))
 308     (if (car result)
 309         (mm-set-handle-multipart-parameter
 310          mm-security-handle 'gnus-info "OK")
 311       (mm-set-handle-multipart-parameter
 312        mm-security-handle 'gnus-info "Failed"))))
 313
 314 (defun mml2015-fix-micalg (alg)
 315   (and alg
 316        ;; Mutt/1.2.5i has seen sending micalg=php-sha1
 317        (upcase (if (string-match "^p[gh]p-" alg)
 318                    (substring alg (match-end 0))
 319                  alg))))
 320
 321 (defun mml2015-mailcrypt-verify (handle ctl)
 322   (catch 'error
 323     (let (part)
 324       (unless (setq part (mm-find-raw-part-by-type
 325                           ctl (or (mm-handle-multipart-ctl-parameter
 326                                    ctl 'protocol)
 327                                   "application/pgp-signature")
 328                           t))
 329         (mm-set-handle-multipart-parameter
 330          mm-security-handle 'gnus-info "Corrupted")
 331         (throw 'error handle))
 332       (with-temp-buffer
 333         (insert "-----BEGIN PGP SIGNED MESSAGE-----\n")
 334         (insert (format "Hash: %s\n\n"
 335                         (or (mml2015-fix-micalg
 336                              (mm-handle-multipart-ctl-parameter
 337                               ctl 'micalg))
 338                             "SHA1")))
 339         (save-restriction
 340           (narrow-to-region (point) (point))
 341           (insert part "\n")
 342           (goto-char (point-min))
 343           (while (not (eobp))
 344             (if (looking-at "^-")
 345                 (insert "- "))
 346             (forward-line)))
 347         (unless (setq part (mm-find-part-by-type
 348                             (cdr handle) "application/pgp-signature" nil t))
 349           (mm-set-handle-multipart-parameter
 350            mm-security-handle 'gnus-info "Corrupted")
 351           (throw 'error handle))
 352         (save-restriction
 353           (narrow-to-region (point) (point))
 354           (mm-insert-part part)
 355           (goto-char (point-min))
 356           (if (re-search-forward "^-----BEGIN PGP [^-]+-----\r?$" nil t)
 357               (replace-match "-----BEGIN PGP SIGNATURE-----" t t))
 358           (if (re-search-forward "^-----END PGP [^-]+-----\r?$" nil t)
 359               (replace-match "-----END PGP SIGNATURE-----" t t)))
 360         (let ((mc-gpg-debug-buffer (get-buffer-create " *gnus gpg debug*")))
 361           (unless (condition-case err
 362                       (prog1
 363                           (funcall mml2015-verify-function)
 364                         (if (get-buffer " *mailcrypt stderr temp")
 365                             (mm-set-handle-multipart-parameter
 366                              mm-security-handle 'gnus-details
 367                              (with-current-buffer " *mailcrypt stderr temp"
 368                                (buffer-string))))
 369                         (if (get-buffer " *mailcrypt stdout temp")
 370                             (kill-buffer " *mailcrypt stdout temp"))
 371                         (if (get-buffer " *mailcrypt stderr temp")
 372                             (kill-buffer " *mailcrypt stderr temp"))
 373                         (if (get-buffer " *mailcrypt status temp")
 374                             (kill-buffer " *mailcrypt status temp"))
 375                         (if (get-buffer mc-gpg-debug-buffer)
 376                             (kill-buffer mc-gpg-debug-buffer)))
 377                     (error
 378                      (mm-set-handle-multipart-parameter
 379                       mm-security-handle 'gnus-details (mml2015-format-error err))
 380                      nil)
 381                     (quit
 382                      (mm-set-handle-multipart-parameter
 383                       mm-security-handle 'gnus-details "Quit.")
 384                      nil))
 385             (mm-set-handle-multipart-parameter
 386              mm-security-handle 'gnus-info "Failed")
 387             (throw 'error handle))))
 388       (mm-set-handle-multipart-parameter
 389        mm-security-handle 'gnus-info "OK")
 390       handle)))
 391
 392 (defun mml2015-mailcrypt-clear-verify ()
 393   (let ((mc-gpg-debug-buffer (get-buffer-create " *gnus gpg debug*")))
 394     (if (condition-case err
 395             (prog1
 396                 (funcall mml2015-verify-function)
 397               (if (get-buffer " *mailcrypt stderr temp")
 398                   (mm-set-handle-multipart-parameter
 399                    mm-security-handle 'gnus-details
 400                    (with-current-buffer " *mailcrypt stderr temp"
 401                      (buffer-string))))
 402               (if (get-buffer " *mailcrypt stdout temp")
 403                   (kill-buffer " *mailcrypt stdout temp"))
 404               (if (get-buffer " *mailcrypt stderr temp")
 405                   (kill-buffer " *mailcrypt stderr temp"))
 406               (if (get-buffer " *mailcrypt status temp")
 407                   (kill-buffer " *mailcrypt status temp"))
 408               (if (get-buffer mc-gpg-debug-buffer)
 409                   (kill-buffer mc-gpg-debug-buffer)))
 410           (error
 411            (mm-set-handle-multipart-parameter
 412             mm-security-handle 'gnus-details (mml2015-format-error err))
 413            nil)
 414           (quit
 415            (mm-set-handle-multipart-parameter
 416             mm-security-handle 'gnus-details "Quit.")
 417            nil))
 418         (mm-set-handle-multipart-parameter
 419          mm-security-handle 'gnus-info "OK")
 420       (mm-set-handle-multipart-parameter
 421        mm-security-handle 'gnus-info "Failed")))
 422   (mml2015-extract-cleartext-signature))
 423
 424 (defun mml2015-mailcrypt-sign (cont)
 425   (mc-sign-generic (message-options-get 'message-sender)
 426                    nil nil nil nil)
 427   (let ((boundary (mml-compute-boundary cont))
 428         hash point)
 429     (goto-char (point-min))
 430     (unless (re-search-forward "^-----BEGIN PGP SIGNED MESSAGE-----\r?$" nil t)
 431       (error "Cannot find signed begin line"))
 432     (goto-char (match-beginning 0))
 433     (forward-line 1)
 434     (unless (looking-at "Hash:[ \t]*\\([a-zA-Z0-9]+\\)")
 435       (error "Cannot not find PGP hash"))
 436     (setq hash (match-string 1))
 437     (unless (re-search-forward "^$" nil t)
 438       (error "Cannot not find PGP message"))
 439     (forward-line 1)
 440     (delete-region (point-min) (point))
 441     (insert (format "Content-Type: multipart/signed; boundary=\"%s\";\n"
 442                     boundary))
 443     (insert (format "\tmicalg=pgp-%s; protocol=\"application/pgp-signature\"\n"
 444                     (downcase hash)))
 445     (insert (format "\n--%s\n" boundary))
 446     (setq point (point))
 447     (goto-char (point-max))
 448     (unless (re-search-backward "^-----END PGP SIGNATURE-----\r?$" nil t)
 449       (error "Cannot find signature part"))
 450     (replace-match "-----END PGP MESSAGE-----" t t)
 451     (goto-char (match-beginning 0))
 452     (unless (re-search-backward "^-----BEGIN PGP SIGNATURE-----\r?$"
 453                                 nil t)
 454       (error "Cannot find signature part"))
 455     (replace-match "-----BEGIN PGP MESSAGE-----" t t)
 456     (goto-char (match-beginning 0))
 457     (save-restriction
 458       (narrow-to-region point (point))
 459       (goto-char point)
 460       (while (re-search-forward "^- -" nil t)
 461         (replace-match "-" t t))
 462       (goto-char (point-max)))
 463     (insert (format "--%s\n" boundary))
 464     (insert "Content-Type: application/pgp-signature\n\n")
 465     (goto-char (point-max))
 466     (insert (format "--%s--\n" boundary))
 467     (goto-char (point-max))))
 468
 469 ;; We require mm-decode, which requires mm-bodies, which autoloads
 470 ;; message-options-get (!).
 471 (declare-function message-options-set "message" (symbol value))
 472
 473 (defun mml2015-mailcrypt-encrypt (cont &optional sign)
 474   (let ((mc-pgp-always-sign
 475          (or mc-pgp-always-sign
 476              sign
 477              (eq t (or (message-options-get 'message-sign-encrypt)
 478                        (message-options-set
 479                         'message-sign-encrypt
 480                         (or (y-or-n-p "Sign the message? ")
 481                             'not))))
 482              'never)))
 483     (mm-with-unibyte-current-buffer
 484       (mc-encrypt-generic
 485        (or (message-options-get 'message-recipients)
 486            (message-options-set 'message-recipients
 487                               (mc-cleanup-recipient-headers
 488                                (read-string "Recipients: "))))
 489        nil nil nil
 490        (message-options-get 'message-sender))))
 491   (goto-char (point-min))
 492   (unless (looking-at "-----BEGIN PGP MESSAGE-----")
 493     (error "Fail to encrypt the message"))
 494   (let ((boundary (mml-compute-boundary cont)))
 495     (insert (format "Content-Type: multipart/encrypted; boundary=\"%s\";\n"
 496                     boundary))
 497     (insert "\tprotocol=\"application/pgp-encrypted\"\n\n")
 498     (insert (format "--%s\n" boundary))
 499     (insert "Content-Type: application/pgp-encrypted\n\n")
 500     (insert "Version: 1\n\n")
 501     (insert (format "--%s\n" boundary))
 502     (insert "Content-Type: application/octet-stream\n\n")
 503     (goto-char (point-max))
 504     (insert (format "--%s--\n" boundary))
 505     (goto-char (point-max))))
 506
 507 ;;; pgg wrapper
 508
 509 (defvar pgg-default-user-id)
 510 (defvar pgg-errors-buffer)
 511 (defvar pgg-output-buffer)
 512
 513 (autoload 'pgg-decrypt-region "pgg")
 514 (autoload 'pgg-verify-region "pgg")
 515 (autoload 'pgg-sign-region "pgg")
 516 (autoload 'pgg-encrypt-region "pgg")
 517 (autoload 'pgg-parse-armor "pgg-parse")
 518
 519 (defun mml2015-pgg-decrypt (handle ctl)
 520   (catch 'error
 521     (let ((pgg-errors-buffer mml2015-result-buffer)
 522           child handles result decrypt-status)
 523       (unless (setq child (mm-find-part-by-type
 524                            (cdr handle)
 525                            "application/octet-stream" nil t))
 526         (mm-set-handle-multipart-parameter
 527          mm-security-handle 'gnus-info "Corrupted")
 528         (throw 'error handle))
 529       (with-temp-buffer
 530         (mm-insert-part child)
 531         (if (condition-case err
 532                 (prog1
 533                     (pgg-decrypt-region (point-min) (point-max))
 534                   (setq decrypt-status
 535                         (with-current-buffer mml2015-result-buffer
 536                           (buffer-string)))
 537                   (mm-set-handle-multipart-parameter
 538                    mm-security-handle 'gnus-details
 539                    decrypt-status))
 540               (error
 541                (mm-set-handle-multipart-parameter
 542                 mm-security-handle 'gnus-details (mml2015-format-error err))
 543                nil)
 544               (quit
 545                (mm-set-handle-multipart-parameter
 546                 mm-security-handle 'gnus-details "Quit.")
 547                nil))
 548             (with-current-buffer pgg-output-buffer
 549               (goto-char (point-min))
 550               (while (search-forward "\r\n" nil t)
 551                 (replace-match "\n" t t))
 552               (setq handles (mm-dissect-buffer t))
 553               (mm-destroy-parts handle)
 554               (mm-set-handle-multipart-parameter
 555                mm-security-handle 'gnus-info "OK")
 556               (mm-set-handle-multipart-parameter
 557                mm-security-handle 'gnus-details
 558                (concat decrypt-status
 559                        (when (stringp (car handles))
 560                          "\n" (mm-handle-multipart-ctl-parameter
 561                                handles 'gnus-details))))
 562               (if (listp (car handles))
 563                   handles
 564                 (list handles)))
 565           (mm-set-handle-multipart-parameter
 566            mm-security-handle 'gnus-info "Failed")
 567           (throw 'error handle))))))
 568
 569 (defun mml2015-pgg-clear-decrypt ()
 570   (let ((pgg-errors-buffer mml2015-result-buffer))
 571     (if (prog1
 572             (pgg-decrypt-region (point-min) (point-max))
 573           (mm-set-handle-multipart-parameter
 574            mm-security-handle 'gnus-details
 575            (with-current-buffer mml2015-result-buffer
 576              (buffer-string))))
 577         (progn
 578           (erase-buffer)
 579           ;; Treat data which pgg returns as a unibyte string.
 580           (mm-disable-multibyte)
 581           (insert-buffer-substring pgg-output-buffer)
 582           (goto-char (point-min))
 583           (while (search-forward "\r\n" nil t)
 584             (replace-match "\n" t t))
 585           (mm-set-handle-multipart-parameter
 586            mm-security-handle 'gnus-info "OK"))
 587       (mm-set-handle-multipart-parameter
 588        mm-security-handle 'gnus-info "Failed"))))
 589
 590 (defun mml2015-pgg-verify (handle ctl)
 591   (let ((pgg-errors-buffer mml2015-result-buffer)
 592         signature-file part signature)
 593     (if (or (null (setq part (mm-find-raw-part-by-type
 594                               ctl (or (mm-handle-multipart-ctl-parameter
 595                                        ctl 'protocol)
 596                                       "application/pgp-signature")
 597                               t)))
 598             (null (setq signature (mm-find-part-by-type
 599                                    (cdr handle) "application/pgp-signature" nil t))))
 600         (progn
 601           (mm-set-handle-multipart-parameter
 602            mm-security-handle 'gnus-info "Corrupted")
 603           handle)
 604       (with-temp-buffer
 605         (insert part)
 606         ;; Convert <LF> to <CR><LF> in signed text.  If --textmode is
 607         ;; specified when signing, the conversion is not necessary.
 608         (goto-char (point-min))
 609         (end-of-line)
 610         (while (not (eobp))
 611           (unless (eq (char-before) ?\r)
 612             (insert "\r"))
 613           (forward-line)
 614           (end-of-line))
 615         (with-temp-file (setq signature-file (mm-make-temp-file "pgg"))
 616           (mm-insert-part signature))
 617         (if (condition-case err
 618                 (prog1
 619                     (pgg-verify-region (point-min) (point-max)
 620                                        signature-file t)
 621                   (goto-char (point-min))
 622                   (while (search-forward "\r\n" nil t)
 623                     (replace-match "\n" t t))
 624                   (mm-set-handle-multipart-parameter
 625                    mm-security-handle 'gnus-details
 626                    (concat (with-current-buffer pgg-output-buffer
 627                              (buffer-string))
 628                            (with-current-buffer pgg-errors-buffer
 629                              (buffer-string)))))
 630               (error
 631                (mm-set-handle-multipart-parameter
 632                 mm-security-handle 'gnus-details (mml2015-format-error err))
 633                nil)
 634               (quit
 635                (mm-set-handle-multipart-parameter
 636                 mm-security-handle 'gnus-details "Quit.")
 637                nil))
 638             (progn
 639               (delete-file signature-file)
 640               (mm-set-handle-multipart-parameter
 641                mm-security-handle 'gnus-info
 642                (with-current-buffer pgg-errors-buffer
 643                  (mml2015-gpg-extract-signature-details))))
 644           (delete-file signature-file)
 645           (mm-set-handle-multipart-parameter
 646            mm-security-handle 'gnus-info "Failed")))))
 647   handle)
 648
 649 (defun mml2015-pgg-clear-verify ()
 650   (let ((pgg-errors-buffer mml2015-result-buffer)
 651         (text (buffer-string))
 652         (coding-system buffer-file-coding-system))
 653     (if (condition-case err
 654             (prog1
 655                 (mm-with-unibyte-buffer
 656                   (insert (mm-encode-coding-string text coding-system))
 657                   (pgg-verify-region (point-min) (point-max) nil t))
 658               (goto-char (point-min))
 659               (while (search-forward "\r\n" nil t)
 660                 (replace-match "\n" t t))
 661               (mm-set-handle-multipart-parameter
 662                mm-security-handle 'gnus-details
 663                (concat (with-current-buffer pgg-output-buffer
 664                          (buffer-string))
 665                        (with-current-buffer pgg-errors-buffer
 666                          (buffer-string)))))
 667           (error
 668            (mm-set-handle-multipart-parameter
 669             mm-security-handle 'gnus-details (mml2015-format-error err))
 670            nil)
 671           (quit
 672            (mm-set-handle-multipart-parameter
 673             mm-security-handle 'gnus-details "Quit.")
 674            nil))
 675         (mm-set-handle-multipart-parameter
 676          mm-security-handle 'gnus-info
 677          (with-current-buffer pgg-errors-buffer
 678            (mml2015-gpg-extract-signature-details)))
 679       (mm-set-handle-multipart-parameter
 680        mm-security-handle 'gnus-info "Failed")))
 681   (mml2015-extract-cleartext-signature))
 682
 683 (defun mml2015-pgg-sign (cont)
 684   (let ((pgg-errors-buffer mml2015-result-buffer)
 685         (boundary (mml-compute-boundary cont))
 686         (pgg-default-user-id (or (message-options-get 'mml-sender)
 687                                  pgg-default-user-id))
 688         (pgg-text-mode t)
 689         entry)
 690     (unless (pgg-sign-region (point-min) (point-max))
 691       (pop-to-buffer mml2015-result-buffer)
 692       (error "Sign error"))
 693     (goto-char (point-min))
 694     (insert (format "Content-Type: multipart/signed; boundary=\"%s\";\n"
 695                     boundary))
 696     (if (setq entry (assq 2 (pgg-parse-armor
 697                              (with-current-buffer pgg-output-buffer
 698                                (buffer-string)))))
 699         (setq entry (assq 'hash-algorithm (cdr entry))))
 700     (insert (format "\tmicalg=%s; "
 701                     (if (cdr entry)
 702                         (downcase (format "pgp-%s" (cdr entry)))
 703                       "pgp-sha1")))
 704     (insert "protocol=\"application/pgp-signature\"\n")
 705     (insert (format "\n--%s\n" boundary))
 706     (goto-char (point-max))
 707     (insert (format "\n--%s\n" boundary))
 708     (insert "Content-Type: application/pgp-signature\n\n")
 709     (insert-buffer-substring pgg-output-buffer)
 710     (goto-char (point-max))
 711     (insert (format "--%s--\n" boundary))
 712     (goto-char (point-max))))
 713
 714 (defun mml2015-pgg-encrypt (cont &optional sign)
 715   (let ((pgg-errors-buffer mml2015-result-buffer)
 716         (pgg-text-mode t)
 717         (boundary (mml-compute-boundary cont)))
 718     (unless (pgg-encrypt-region (point-min) (point-max)
 719                                 (split-string
 720                                  (or
 721                                   (message-options-get 'message-recipients)
 722                                   (message-options-set 'message-recipients
 723                                                        (read-string "Recipients: ")))
 724                                  "[ \f\t\n\r\v,]+")
 725                                 sign)
 726       (pop-to-buffer mml2015-result-buffer)
 727       (error "Encrypt error"))
 728     (delete-region (point-min) (point-max))
 729     (goto-char (point-min))
 730     (insert (format "Content-Type: multipart/encrypted; boundary=\"%s\";\n"
 731                     boundary))
 732     (insert "\tprotocol=\"application/pgp-encrypted\"\n\n")
 733     (insert (format "--%s\n" boundary))
 734     (insert "Content-Type: application/pgp-encrypted\n\n")
 735     (insert "Version: 1\n\n")
 736     (insert (format "--%s\n" boundary))
 737     (insert "Content-Type: application/octet-stream\n\n")
 738     (insert-buffer-substring pgg-output-buffer)
 739     (goto-char (point-max))
 740     (insert (format "--%s--\n" boundary))
 741     (goto-char (point-max))))
 742
 743 ;;; epg wrapper
 744
 745 (defvar epg-user-id-alist)
 746 (defvar epg-digest-algorithm-alist)
 747 (defvar epg-gpg-program)
 748 (defvar inhibit-redisplay)
 749
 750 (autoload 'epg-make-context "epg")
 751 (autoload 'epg-context-set-armor "epg")
 752 (autoload 'epg-context-set-textmode "epg")
 753 (autoload 'epg-context-set-signers "epg")
 754 (autoload 'epg-context-result-for "epg")
 755 (autoload 'epg-new-signature-digest-algorithm "epg")
 756 (autoload 'epg-list-keys "epg")
 757 (autoload 'epg-decrypt-string "epg")
 758 (autoload 'epg-verify-string "epg")
 759 (autoload 'epg-sign-string "epg")
 760 (autoload 'epg-encrypt-string "epg")
 761 (autoload 'epg-passphrase-callback-function "epg")
 762 (autoload 'epg-context-set-passphrase-callback "epg")
 763 (autoload 'epg-key-sub-key-list "epg")
 764 (autoload 'epg-sub-key-capability "epg")
 765 (autoload 'epg-sub-key-validity "epg")
 766 (autoload 'epg-sub-key-fingerprint "epg")
 767 (autoload 'epg-signature-key-id "epg")
 768 (autoload 'epg-signature-to-string "epg")
 769 (autoload 'epg-key-user-id-list "epg")
 770 (autoload 'epg-user-id-string "epg")
 771 (autoload 'epg-user-id-validity "epg")
 772 (autoload 'epg-configuration "epg-config")
 773 (autoload 'epg-expand-group "epg-config")
 774 (autoload 'epa-select-keys "epa")
 775
 776 (defvar mml2015-epg-secret-key-id-list nil)
 777
 778 (defun mml2015-epg-passphrase-callback (context key-id ignore)
 779   (if (eq key-id 'SYM)
 780       (epg-passphrase-callback-function context key-id nil)
 781     (let* ((password-cache-key-id
 782             (if (eq key-id 'PIN)
 783                 "PIN"
 784                key-id))
 785            entry
 786            (passphrase
 787             (password-read
 788              (if (eq key-id 'PIN)
 789                  "Passphrase for PIN: "
 790                (if (setq entry (assoc key-id epg-user-id-alist))
 791                    (format "Passphrase for %s %s: " key-id (cdr entry))
 792                  (format "Passphrase for %s: " key-id)))
 793              password-cache-key-id)))
 794       (when passphrase
 795         (let ((password-cache-expiry mml2015-passphrase-cache-expiry))
 796           (password-cache-add password-cache-key-id passphrase))
 797         (setq mml2015-epg-secret-key-id-list
 798               (cons password-cache-key-id mml2015-epg-secret-key-id-list))
 799         (copy-sequence passphrase)))))
 800
 801 (defun mml2015-epg-check-user-id (key recipient)
 802   (let ((pointer (epg-key-user-id-list key))
 803         result)
 804     (while pointer
 805       (if (and (equal (car (mail-header-parse-address
 806                             (epg-user-id-string (car pointer))))
 807                       (car (mail-header-parse-address
 808                             recipient)))
 809                (not (memq (epg-user-id-validity (car pointer))
 810                           '(revoked expired))))
 811           (setq result t
 812                 pointer nil)
 813         (setq pointer (cdr pointer))))
 814     result))
 815
 816 (defun mml2015-epg-check-sub-key (key usage)
 817   (let ((pointer (epg-key-sub-key-list key))
 818         result)
 819     ;; The primary key will be marked as disabled, when the entire
 820     ;; key is disabled (see 12 Field, Format of colon listings, in
 821     ;; gnupg/doc/DETAILS)
 822     (unless (memq 'disabled (epg-sub-key-capability (car pointer)))
 823       (while pointer
 824         (if (and (memq usage (epg-sub-key-capability (car pointer)))
 825                  (not (memq (epg-sub-key-validity (car pointer))
 826                             '(revoked expired))))
 827             (setq result t
 828                   pointer nil)
 829           (setq pointer (cdr pointer)))))
 830     result))
 831
 832 (defun mml2015-epg-find-usable-key (context name usage
 833                                             &optional name-is-key-id)
 834   (let ((keys (epg-list-keys context name))
 835         key)
 836     (while keys
 837       (if (and (or name-is-key-id
 838                    ;; Non email user-id can be supplied through
 839                    ;; mml2015-signers if mml2015-encrypt-to-self is set.
 840                    ;; Treat it as valid, as it is user's intention.
 841                    (not (string-match "\\`<" name))
 842                    (mml2015-epg-check-user-id (car keys) name))
 843                (mml2015-epg-check-sub-key (car keys) usage))
 844           (setq key (car keys)
 845                 keys nil)
 846         (setq keys (cdr keys))))
 847     key))
 848
 849 ;; XXX: since gpg --list-secret-keys does not return validity of each
 850 ;; key, `mml2015-epg-find-usable-key' defined above is not enough for
 851 ;; secret keys.  The function `mml2015-epg-find-usable-secret-key'
 852 ;; below looks at appropriate public keys to check usability.
 853 (defun mml2015-epg-find-usable-secret-key (context name usage)
 854   (let ((secret-keys (epg-list-keys context name t))
 855         secret-key)
 856     (while (and (not secret-key) secret-keys)
 857       (if (mml2015-epg-find-usable-key
 858            context
 859            (epg-sub-key-fingerprint
 860             (car (epg-key-sub-key-list
 861                   (car secret-keys))))
 862            usage
 863            t)
 864           (setq secret-key (car secret-keys)
 865                 secret-keys nil)
 866         (setq secret-keys (cdr secret-keys))))
 867     secret-key))
 868
 869 (autoload 'gnus-create-image "gnus-ems")
 870
 871 (defun mml2015-epg-key-image (key-id)
 872   "Return the image of a key, if any"
 873   (with-temp-buffer
 874     (mm-set-buffer-multibyte nil)
 875     (let* ((coding-system-for-write 'binary)
 876            (coding-system-for-read 'binary)
 877            (data (shell-command-to-string
 878                   (format "%s --list-options no-show-photos --attribute-fd 3 --list-keys %s 3>&1 >/dev/null 2>&1"
 879                           (shell-quote-argument epg-gpg-program) key-id))))
 880       (when (> (length data) 0)
 881         (insert (substring data 16))
 882         (condition-case nil
 883             (gnus-create-image (buffer-string) nil t)
 884           (error))))))
 885
 886 (autoload 'gnus-rescale-image "gnus-util")
 887
 888 (defun mml2015-epg-key-image-to-string (key-id)
 889   "Return a string with the image of a key, if any"
 890   (let ((key-image (mml2015-epg-key-image key-id)))
 891     (if (not key-image)
 892         ""
 893       (condition-case error
 894           (let ((result "  "))
 895             (put-text-property
 896              1 2 'display
 897              (gnus-rescale-image key-image
 898                                  (cons mml2015-maximum-key-image-dimension
 899                                        mml2015-maximum-key-image-dimension))
 900              result)
 901             result)
 902         (error "")))))
 903
 904 (defun mml2015-epg-signature-to-string (signature)
 905   (concat (epg-signature-to-string signature)
 906           (mml2015-epg-key-image-to-string (epg-signature-key-id signature))))
 907
 908 (defun mml2015-epg-verify-result-to-string (verify-result)
 909   (mapconcat #'mml2015-epg-signature-to-string verify-result "\n"))
 910
 911 (defun mml2015-epg-decrypt (handle ctl)
 912   (catch 'error
 913     (let ((inhibit-redisplay t)
 914           context plain child handles result decrypt-status)
 915       (unless (setq child (mm-find-part-by-type
 916                            (cdr handle)
 917                            "application/octet-stream" nil t))
 918         (mm-set-handle-multipart-parameter
 919          mm-security-handle 'gnus-info "Corrupted")
 920         (throw 'error handle))
 921       (setq context (epg-make-context))
 922       (if mml2015-cache-passphrase
 923           (epg-context-set-passphrase-callback
 924            context
 925            #'mml2015-epg-passphrase-callback))
 926       (condition-case error
 927           (setq plain (epg-decrypt-string context (mm-get-part child))
 928                 mml2015-epg-secret-key-id-list nil)
 929         (error
 930          (while mml2015-epg-secret-key-id-list
 931            (password-cache-remove (car mml2015-epg-secret-key-id-list))
 932            (setq mml2015-epg-secret-key-id-list
 933                  (cdr mml2015-epg-secret-key-id-list)))
 934          (mm-set-handle-multipart-parameter
 935           mm-security-handle 'gnus-info "Failed")
 936          (if (eq (car error) 'quit)
 937              (mm-set-handle-multipart-parameter
 938               mm-security-handle 'gnus-details "Quit.")
 939            (mm-set-handle-multipart-parameter
 940             mm-security-handle 'gnus-details (mml2015-format-error error)))
 941          (throw 'error handle)))
 942       (with-temp-buffer
 943         (insert plain)
 944         (goto-char (point-min))
 945         (while (search-forward "\r\n" nil t)
 946           (replace-match "\n" t t))
 947         (setq handles (mm-dissect-buffer t))
 948         (mm-destroy-parts handle)
 949         (if (epg-context-result-for context 'verify)
 950             (mm-set-handle-multipart-parameter
 951              mm-security-handle 'gnus-info
 952              (concat "OK\n"
 953                      (mml2015-epg-verify-result-to-string
 954                       (epg-context-result-for context 'verify))))
 955           (mm-set-handle-multipart-parameter
 956            mm-security-handle 'gnus-info "OK"))
 957         (if (stringp (car handles))
 958             (mm-set-handle-multipart-parameter
 959              mm-security-handle 'gnus-details
 960              (mm-handle-multipart-ctl-parameter handles 'gnus-details))))
 961         (if (listp (car handles))
 962             handles
 963           (list handles)))))
 964
 965 (defun mml2015-epg-clear-decrypt ()
 966   (let ((inhibit-redisplay t)
 967         (context (epg-make-context))
 968         plain)
 969     (if mml2015-cache-passphrase
 970         (epg-context-set-passphrase-callback
 971          context
 972          #'mml2015-epg-passphrase-callback))
 973     (condition-case error
 974         (setq plain (epg-decrypt-string context (buffer-string))
 975               mml2015-epg-secret-key-id-list nil)
 976       (error
 977        (while mml2015-epg-secret-key-id-list
 978          (password-cache-remove (car mml2015-epg-secret-key-id-list))
 979          (setq mml2015-epg-secret-key-id-list
 980                (cdr mml2015-epg-secret-key-id-list)))
 981        (mm-set-handle-multipart-parameter
 982         mm-security-handle 'gnus-info "Failed")
 983        (if (eq (car error) 'quit)
 984            (mm-set-handle-multipart-parameter
 985             mm-security-handle 'gnus-details "Quit.")
 986          (mm-set-handle-multipart-parameter
 987           mm-security-handle 'gnus-details (mml2015-format-error error)))))
 988     (when plain
 989       (erase-buffer)
 990       ;; Treat data which epg returns as a unibyte string.
 991       (mm-disable-multibyte)
 992       (insert plain)
 993       (goto-char (point-min))
 994       (while (search-forward "\r\n" nil t)
 995         (replace-match "\n" t t))
 996       (mm-set-handle-multipart-parameter
 997        mm-security-handle 'gnus-info "OK")
 998       (if (epg-context-result-for context 'verify)
 999           (mm-set-handle-multipart-parameter
1000            mm-security-handle 'gnus-details
1001            (mml2015-epg-verify-result-to-string
1002             (epg-context-result-for context 'verify)))))))
1003
1004 (defun mml2015-epg-verify (handle ctl)
1005   (catch 'error
1006     (let ((inhibit-redisplay t)
1007           context plain signature-file part signature)
1008       (when (or (null (setq part (mm-find-raw-part-by-type
1009                                   ctl (or (mm-handle-multipart-ctl-parameter
1010                                            ctl 'protocol)
1011                                           "application/pgp-signature")
1012                                   t)))
1013                 (null (setq signature (mm-find-part-by-type
1014                                        (cdr handle) "application/pgp-signature"
1015                                        nil t))))
1016         (mm-set-handle-multipart-parameter
1017          mm-security-handle 'gnus-info "Corrupted")
1018         (throw 'error handle))
1019       (setq part (mm-replace-in-string part "\n" "\r\n")
1020             signature (mm-get-part signature)
1021             context (epg-make-context))
1022       (condition-case error
1023           (setq plain (epg-verify-string context signature part))
1024         (error
1025          (mm-set-handle-multipart-parameter
1026           mm-security-handle 'gnus-info "Failed")
1027          (if (eq (car error) 'quit)
1028              (mm-set-handle-multipart-parameter
1029               mm-security-handle 'gnus-details "Quit.")
1030            (mm-set-handle-multipart-parameter
1031             mm-security-handle 'gnus-details (mml2015-format-error error)))
1032          (throw 'error handle)))
1033       (mm-set-handle-multipart-parameter
1034        mm-security-handle 'gnus-info
1035        (mml2015-epg-verify-result-to-string
1036         (epg-context-result-for context 'verify)))
1037       handle)))
1038
1039 (defun mml2015-epg-clear-verify ()
1040   (let ((inhibit-redisplay t)
1041         (context (epg-make-context))
1042         (signature (mm-encode-coding-string (buffer-string)
1043                                             coding-system-for-write))
1044         plain)
1045     (condition-case error
1046         (setq plain (epg-verify-string context signature))
1047       (error
1048        (mm-set-handle-multipart-parameter
1049         mm-security-handle 'gnus-info "Failed")
1050        (if (eq (car error) 'quit)
1051            (mm-set-handle-multipart-parameter
1052             mm-security-handle 'gnus-details "Quit.")
1053          (mm-set-handle-multipart-parameter
1054           mm-security-handle 'gnus-details (mml2015-format-error error)))))
1055     (if plain
1056         (progn
1057           (mm-set-handle-multipart-parameter
1058            mm-security-handle 'gnus-info
1059            (mml2015-epg-verify-result-to-string
1060             (epg-context-result-for context 'verify)))
1061           (delete-region (point-min) (point-max))
1062           (insert (mm-decode-coding-string plain coding-system-for-read)))
1063       (mml2015-extract-cleartext-signature))))
1064
1065 (defun mml2015-epg-sign (cont)
1066   (let* ((inhibit-redisplay t)
1067          (context (epg-make-context))
1068          (boundary (mml-compute-boundary cont))
1069          (sender (message-options-get 'message-sender))
1070          (signer-names (or mml2015-signers
1071                            (if (and mml2015-sign-with-sender sender)
1072                                (list (concat "<" sender ">")))))
1073          signer-key
1074          (signers
1075           (or (message-options-get 'mml2015-epg-signers)
1076               (message-options-set
1077                'mml2015-epg-signers
1078                (if (eq mm-sign-option 'guided)
1079                    (epa-select-keys context "\
1080 Select keys for signing.
1081 If no one is selected, default secret key is used.  "
1082                                     signer-names
1083                                     t)
1084                  (if (or sender mml2015-signers)
1085                      (delq nil
1086                            (mapcar
1087                             (lambda (signer)
1088                               (setq signer-key
1089                                     (mml2015-epg-find-usable-secret-key
1090                                      context signer 'sign))
1091                               (unless (or signer-key
1092                                           (y-or-n-p
1093                                            (format
1094                                             "No secret key for %s; skip it? "
1095                                             signer)))
1096                                 (error "No secret key for %s" signer))
1097                               signer-key)
1098                             signer-names)))))))
1099          signature micalg)
1100     (epg-context-set-armor context t)
1101     (epg-context-set-textmode context t)
1102     (epg-context-set-signers context signers)
1103     (if mml2015-cache-passphrase
1104         (epg-context-set-passphrase-callback
1105          context
1106          #'mml2015-epg-passphrase-callback))
1107     ;; Signed data must end with a newline (RFC 3156, 5).
1108     (goto-char (point-max))
1109     (unless (bolp)
1110       (insert "\n"))
1111     (condition-case error
1112         (setq signature (epg-sign-string context (buffer-string) t)
1113               mml2015-epg-secret-key-id-list nil)
1114       (error
1115        (while mml2015-epg-secret-key-id-list
1116          (password-cache-remove (car mml2015-epg-secret-key-id-list))
1117          (setq mml2015-epg-secret-key-id-list
1118                (cdr mml2015-epg-secret-key-id-list)))
1119        (signal (car error) (cdr error))))
1120     (if (epg-context-result-for context 'sign)
1121         (setq micalg (epg-new-signature-digest-algorithm
1122                       (car (epg-context-result-for context 'sign)))))
1123     (goto-char (point-min))
1124     (insert (format "Content-Type: multipart/signed; boundary=\"%s\";\n"
1125                     boundary))
1126     (if micalg
1127         (insert (format "\tmicalg=pgp-%s; "
1128                         (downcase
1129                          (cdr (assq micalg
1130                                     epg-digest-algorithm-alist))))))
1131     (insert "protocol=\"application/pgp-signature\"\n")
1132     (insert (format "\n--%s\n" boundary))
1133     (goto-char (point-max))
1134     (insert (format "\n--%s\n" boundary))
1135     (insert "Content-Type: application/pgp-signature; name=\"signature.asc\"\n\n")
1136     (insert signature)
1137     (goto-char (point-max))
1138     (insert (format "--%s--\n" boundary))
1139     (goto-char (point-max))))
1140
1141 (defun mml2015-epg-encrypt (cont &optional sign)
1142   (let* ((inhibit-redisplay t)
1143          (context (epg-make-context))
1144          (boundary (mml-compute-boundary cont))
1145          (config (epg-configuration))
1146          (recipients (message-options-get 'mml2015-epg-recipients))
1147          cipher
1148          (sender (message-options-get 'message-sender))
1149          (signer-names (or mml2015-signers
1150                            (if (and mml2015-sign-with-sender sender)
1151                                (list (concat "<" sender ">")))))
1152          signers
1153          recipient-key signer-key)
1154     (unless recipients
1155       (setq recipients
1156             (apply #'nconc
1157                    (mapcar
1158                     (lambda (recipient)
1159                       (or (epg-expand-group config recipient)
1160                           (list (concat "<" recipient ">"))))
1161                     (split-string
1162                      (or (message-options-get 'message-recipients)
1163                          (message-options-set 'message-recipients
1164                                               (read-string "Recipients: ")))
1165                      "[ \f\t\n\r\v,]+"))))
1166       (when mml2015-encrypt-to-self
1167         (unless signer-names
1168           (error "Neither message sender nor mml2015-signers are set"))
1169         (setq recipients (nconc recipients signer-names)))
1170       (if (eq mm-encrypt-option 'guided)
1171           (setq recipients
1172                 (epa-select-keys context "\
1173 Select recipients for encryption.
1174 If no one is selected, symmetric encryption will be performed.  "
1175                                  recipients))
1176         (setq recipients
1177               (delq nil
1178                     (mapcar
1179                      (lambda (recipient)
1180                        (setq recipient-key (mml2015-epg-find-usable-key
1181                                             context recipient 'encrypt))
1182                        (unless (or recipient-key
1183                                    (y-or-n-p
1184                                     (format "No public key for %s; skip it? "
1185                                             recipient)))
1186                          (error "No public key for %s" recipient))
1187                        recipient-key)
1188                      recipients)))
1189         (unless recipients
1190           (error "No recipient specified")))
1191       (message-options-set 'mml2015-epg-recipients recipients))
1192     (when sign
1193       (setq signers
1194             (or (message-options-get 'mml2015-epg-signers)
1195                 (message-options-set
1196                  'mml2015-epg-signers
1197                  (if (eq mm-sign-option 'guided)
1198                      (epa-select-keys context "\
1199 Select keys for signing.
1200 If no one is selected, default secret key is used.  "
1201                                       signer-names
1202                                       t)
1203                    (if (or sender mml2015-signers)
1204                        (delq nil
1205                              (mapcar
1206                               (lambda (signer)
1207                                 (setq signer-key
1208                                       (mml2015-epg-find-usable-secret-key
1209                                        context signer 'sign))
1210                                 (unless (or signer-key
1211                                             (y-or-n-p
1212                                              (format
1213                                               "No secret key for %s; skip it? "
1214                                               signer)))
1215                                   (error "No secret key for %s" signer))
1216                                 signer-key)
1217                               signer-names)))))))
1218       (epg-context-set-signers context signers))
1219     (epg-context-set-armor context t)
1220     (epg-context-set-textmode context t)
1221     (if mml2015-cache-passphrase
1222         (epg-context-set-passphrase-callback
1223          context
1224          #'mml2015-epg-passphrase-callback))
1225     (condition-case error
1226         (setq cipher
1227               (epg-encrypt-string context (buffer-string) recipients sign
1228                                   mml2015-always-trust)
1229               mml2015-epg-secret-key-id-list nil)
1230       (error
1231        (while mml2015-epg-secret-key-id-list
1232          (password-cache-remove (car mml2015-epg-secret-key-id-list))
1233          (setq mml2015-epg-secret-key-id-list
1234                (cdr mml2015-epg-secret-key-id-list)))
1235        (signal (car error) (cdr error))))
1236     (delete-region (point-min) (point-max))
1237     (goto-char (point-min))
1238     (insert (format "Content-Type: multipart/encrypted; boundary=\"%s\";\n"
1239                     boundary))
1240     (insert "\tprotocol=\"application/pgp-encrypted\"\n\n")
1241     (insert (format "--%s\n" boundary))
1242     (insert "Content-Type: application/pgp-encrypted\n\n")
1243     (insert "Version: 1\n\n")
1244     (insert (format "--%s\n" boundary))
1245     (insert "Content-Type: application/octet-stream\n\n")
1246     (insert cipher)
1247     (goto-char (point-max))
1248     (insert (format "--%s--\n" boundary))
1249     (goto-char (point-max))))
1250
1251 ;;; General wrapper
1252
1253 (autoload 'gnus-buffer-live-p "gnus-util")
1254 (autoload 'gnus-get-buffer-create "gnus")
1255
1256 (defun mml2015-clean-buffer ()
1257   (if (gnus-buffer-live-p mml2015-result-buffer)
1258       (with-current-buffer mml2015-result-buffer
1259         (erase-buffer)
1260         t)
1261     (setq mml2015-result-buffer
1262           (gnus-get-buffer-create " *MML2015 Result*"))
1263     nil))
1264
1265 (defsubst mml2015-clear-decrypt-function ()
1266   (nth 6 (assq mml2015-use mml2015-function-alist)))
1267
1268 (defsubst mml2015-clear-verify-function ()
1269   (nth 5 (assq mml2015-use mml2015-function-alist)))
1270
1271 ;;;###autoload
1272 (defun mml2015-decrypt (handle ctl)
1273   (mml2015-clean-buffer)
1274   (let ((func (nth 4 (assq mml2015-use mml2015-function-alist))))
1275     (if func
1276         (funcall func handle ctl)
1277       handle)))
1278
1279 ;;;###autoload
1280 (defun mml2015-decrypt-test (handle ctl)
1281   mml2015-use)
1282
1283 ;;;###autoload
1284 (defun mml2015-verify (handle ctl)
1285   (mml2015-clean-buffer)
1286   (let ((func (nth 3 (assq mml2015-use mml2015-function-alist))))
1287     (if func
1288         (funcall func handle ctl)
1289       handle)))
1290
1291 ;;;###autoload
1292 (defun mml2015-verify-test (handle ctl)
1293   mml2015-use)
1294
1295 ;;;###autoload
1296 (defun mml2015-encrypt (cont &optional sign)
1297   (mml2015-clean-buffer)
1298   (let ((func (nth 2 (assq mml2015-use mml2015-function-alist))))
1299     (if func
1300         (funcall func cont sign)
1301       (error "Cannot find encrypt function"))))
1302
1303 ;;;###autoload
1304 (defun mml2015-sign (cont)
1305   (mml2015-clean-buffer)
1306   (let ((func (nth 1 (assq mml2015-use mml2015-function-alist))))
1307     (if func
1308         (funcall func cont)
1309       (error "Cannot find sign function"))))
1310
1311 ;;;###autoload
1312 (defun mml2015-self-encrypt ()
1313   (mml2015-encrypt nil))
1314
1315 (provide 'mml2015)
1316
1317 ;;; mml2015.el ends here