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emacs/lisp/pgg-gpg.el
2010-01-13 00:35:10 -08:00

411 lines
15 KiB
EmacsLisp

;;; pgg-gpg.el --- GnuPG support for PGG.
;; Copyright (C) 1999, 2000, 2002, 2003, 2004,
;; 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
;; Author: Daiki Ueno <ueno@unixuser.org>
;; Symmetric encryption and gpg-agent support added by:
;; Sascha Wilde <wilde@sha-bang.de>
;; Created: 1999/10/28
;; Keywords: PGP, OpenPGP, GnuPG
;; This file is part of GNU Emacs.
;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.
;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
;;; Code:
(eval-when-compile
(require 'cl) ; for gpg macros
(require 'pgg))
(defgroup pgg-gpg ()
"GnuPG interface."
:group 'pgg)
(defcustom pgg-gpg-program "gpg"
"The GnuPG executable."
:group 'pgg-gpg
:type 'string)
(defcustom pgg-gpg-extra-args nil
"Extra arguments for every GnuPG invocation."
:group 'pgg-gpg
:type '(repeat (string :tag "Argument")))
(defcustom pgg-gpg-recipient-argument "--recipient"
"GnuPG option to specify recipient."
:group 'pgg-gpg
:type '(choice (const :tag "New `--recipient' option" "--recipient")
(const :tag "Old `--remote-user' option" "--remote-user")))
(defcustom pgg-gpg-use-agent t
"Whether to use gnupg agent for key caching."
:group 'pgg-gpg
:type 'boolean)
(defvar pgg-gpg-user-id nil
"GnuPG ID of your default identity.")
(defun pgg-gpg-process-region (start end passphrase program args)
(let* ((use-agent (and (null passphrase) (pgg-gpg-use-agent-p)))
(output-file-name (pgg-make-temp-file "pgg-output"))
(args
`("--status-fd" "2"
,@(if use-agent '("--use-agent")
(if passphrase '("--passphrase-fd" "0")))
"--yes" ; overwrite
"--output" ,output-file-name
,@pgg-gpg-extra-args ,@args))
(output-buffer pgg-output-buffer)
(errors-buffer pgg-errors-buffer)
(orig-mode (default-file-modes))
(process-connection-type nil)
(inhibit-redisplay t)
process status exit-status
passphrase-with-newline
encoded-passphrase-with-new-line)
(with-current-buffer (get-buffer-create errors-buffer)
(buffer-disable-undo)
(erase-buffer))
(unwind-protect
(progn
(set-default-file-modes 448)
(let ((coding-system-for-write 'binary))
(setq process
(apply #'start-process "*GnuPG*" errors-buffer
program args)))
(set-process-sentinel process #'ignore)
(when passphrase
(setq passphrase-with-newline (concat passphrase "\n"))
(if pgg-passphrase-coding-system
(progn
(setq encoded-passphrase-with-new-line
(encode-coding-string
passphrase-with-newline
(coding-system-change-eol-conversion
pgg-passphrase-coding-system 'unix)))
(pgg-clear-string passphrase-with-newline))
(setq encoded-passphrase-with-new-line passphrase-with-newline
passphrase-with-newline nil))
(process-send-string process encoded-passphrase-with-new-line))
(process-send-region process start end)
(process-send-eof process)
(while (eq 'run (process-status process))
(accept-process-output process 5))
;; Accept any remaining pending output coming after the
;; status change.
(accept-process-output process 5)
(setq status (process-status process)
exit-status (process-exit-status process))
(delete-process process)
(with-current-buffer (get-buffer-create output-buffer)
(buffer-disable-undo)
(erase-buffer)
(if (file-exists-p output-file-name)
(let ((coding-system-for-read (if pgg-text-mode
'raw-text
'binary)))
(insert-file-contents output-file-name)))
(set-buffer errors-buffer)
(if (memq status '(stop signal))
(error "%s exited abnormally: '%s'" program exit-status))
(if (= 127 exit-status)
(error "%s could not be found" program))))
(if passphrase-with-newline
(pgg-clear-string passphrase-with-newline))
(if encoded-passphrase-with-new-line
(pgg-clear-string encoded-passphrase-with-new-line))
(if (and process (eq 'run (process-status process)))
(interrupt-process process))
(if (file-exists-p output-file-name)
(delete-file output-file-name))
(set-default-file-modes orig-mode))))
(defun pgg-gpg-possibly-cache-passphrase (passphrase &optional key notruncate)
(if (and passphrase
pgg-cache-passphrase
(progn
(goto-char (point-min))
(re-search-forward "^\\[GNUPG:] \\(GOOD_PASSPHRASE\\>\\)\\|\\(SIG_CREATED\\)" nil t)))
(pgg-add-passphrase-to-cache
(or key
(progn
(goto-char (point-min))
(if (re-search-forward
"^\\[GNUPG:] NEED_PASSPHRASE\\(_PIN\\)? \\w+ ?\\w*" nil t)
(substring (match-string 0) -8))))
passphrase
notruncate)))
(defvar pgg-gpg-all-secret-keys 'unknown)
(defun pgg-gpg-lookup-all-secret-keys ()
"Return all secret keys present in secret key ring."
(when (eq pgg-gpg-all-secret-keys 'unknown)
(setq pgg-gpg-all-secret-keys '())
(let ((args (list "--with-colons" "--no-greeting" "--batch"
"--list-secret-keys")))
(with-temp-buffer
(apply #'call-process pgg-gpg-program nil t nil args)
(goto-char (point-min))
(while (re-search-forward
"^\\(sec\\|pub\\):[^:]*:[^:]*:[^:]*:\\([^:]*\\)" nil t)
(push (substring (match-string 2) 8)
pgg-gpg-all-secret-keys)))))
pgg-gpg-all-secret-keys)
(defun pgg-gpg-lookup-key (string &optional type)
"Search keys associated with STRING."
(let ((args (list "--with-colons" "--no-greeting" "--batch"
(if type "--list-secret-keys" "--list-keys")
string)))
(with-temp-buffer
(apply #'call-process pgg-gpg-program nil t nil args)
(goto-char (point-min))
(if (re-search-forward "^\\(sec\\|pub\\):[^:]*:[^:]*:[^:]*:\\([^:]*\\)"
nil t)
(substring (match-string 2) 8)))))
(defun pgg-gpg-lookup-key-owner (string &optional all)
"Search keys associated with STRING and return owner of identified key.
The value may be just the bare key id, or it may be a combination of the
user name associated with the key and the key id, with the key id enclosed
in \"<...>\" angle brackets.
Optional ALL non-nil means search all keys, including secret keys."
(let ((args (list "--with-colons" "--no-greeting" "--batch"
(if all "--list-secret-keys" "--list-keys")
string))
(key-regexp (concat "^\\(sec\\|pub\\|uid\\)"
":[^:]*:[^:]*:[^:]*:\\([^:]*\\):[^:]*"
":[^:]*:[^:]*:[^:]*:\\([^:]+\\):")))
(with-temp-buffer
(apply #'call-process pgg-gpg-program nil t nil args)
(goto-char (point-min))
(if (re-search-forward key-regexp
nil t)
(match-string 3)))))
(defun pgg-gpg-key-id-from-key-owner (key-owner)
(cond ((not key-owner) nil)
;; Extract bare key id from outermost paired angle brackets, if any:
((string-match "[^<]*<\\(.+\\)>[^>]*" key-owner)
(substring key-owner (match-beginning 1)(match-end 1)))
(key-owner)))
(defun pgg-gpg-encrypt-region (start end recipients &optional sign passphrase)
"Encrypt the current region between START and END.
If optional argument SIGN is non-nil, do a combined sign and encrypt.
If optional PASSPHRASE is not specified, it will be obtained from the
passphrase cache or user."
(let* ((pgg-gpg-user-id (or pgg-gpg-user-id pgg-default-user-id))
(passphrase (or passphrase
(when (and sign (not (pgg-gpg-use-agent-p)))
(pgg-read-passphrase
(format "GnuPG passphrase for %s: "
pgg-gpg-user-id)
pgg-gpg-user-id))))
(args
(append
(list "--batch" "--armor" "--always-trust" "--encrypt")
(if pgg-text-mode (list "--textmode"))
(if sign (list "--sign" "--local-user" pgg-gpg-user-id))
(if (or recipients pgg-encrypt-for-me)
(apply #'nconc
(mapcar (lambda (rcpt)
(list pgg-gpg-recipient-argument rcpt))
(append recipients
(if pgg-encrypt-for-me
(list pgg-gpg-user-id)))))))))
(pgg-gpg-process-region start end passphrase pgg-gpg-program args)
(when sign
(with-current-buffer pgg-errors-buffer
;; Possibly cache passphrase under, e.g. "jas", for future sign.
(pgg-gpg-possibly-cache-passphrase passphrase pgg-gpg-user-id)
;; Possibly cache passphrase under, e.g. B565716F, for future decrypt.
(pgg-gpg-possibly-cache-passphrase passphrase)))
(pgg-process-when-success)))
(defun pgg-gpg-encrypt-symmetric-region (start end &optional passphrase)
"Encrypt the current region between START and END with symmetric cipher.
If optional PASSPHRASE is not specified, it will be obtained from the
passphrase cache or user."
(let* ((passphrase (or passphrase
(when (not (pgg-gpg-use-agent-p))
(pgg-read-passphrase
"GnuPG passphrase for symmetric encryption: "))))
(args
(append (list "--batch" "--armor" "--symmetric" )
(if pgg-text-mode (list "--textmode")))))
(pgg-gpg-process-region start end passphrase pgg-gpg-program args)
(pgg-process-when-success)))
(defun pgg-gpg-decrypt-region (start end &optional passphrase)
"Decrypt the current region between START and END.
If optional PASSPHRASE is not specified, it will be obtained from the
passphrase cache or user."
(let* ((current-buffer (current-buffer))
(message-keys (with-temp-buffer
(insert-buffer-substring current-buffer)
(pgg-decode-armor-region (point-min) (point-max))))
(secret-keys (pgg-gpg-lookup-all-secret-keys))
;; XXX the user is stuck if they need to use the passphrase for
;; any but the first secret key for which the message is
;; encrypted. ideally, we would incrementally give them a
;; chance with subsequent keys each time they fail with one.
(key (pgg-gpg-select-matching-key message-keys secret-keys))
(key-owner (and key (pgg-gpg-lookup-key-owner key t)))
(key-id (pgg-gpg-key-id-from-key-owner key-owner))
(pgg-gpg-user-id (or key-id key
pgg-gpg-user-id pgg-default-user-id))
(passphrase (or passphrase
(when (not (pgg-gpg-use-agent-p))
(pgg-read-passphrase
(format (if (pgg-gpg-symmetric-key-p message-keys)
"Passphrase for symmetric decryption: "
"GnuPG passphrase for %s: ")
(or key-owner "??"))
pgg-gpg-user-id))))
(args '("--batch" "--decrypt")))
(pgg-gpg-process-region start end passphrase pgg-gpg-program args)
(with-current-buffer pgg-errors-buffer
(pgg-gpg-possibly-cache-passphrase passphrase pgg-gpg-user-id)
(goto-char (point-min))
(re-search-forward "^\\[GNUPG:] DECRYPTION_OKAY\\>" nil t))))
;;;###autoload
(defun pgg-gpg-symmetric-key-p (message-keys)
"True if decoded armor MESSAGE-KEYS has symmetric encryption indicator."
(let (result)
(dolist (key message-keys result)
(when (and (eq (car key) 3)
(member '(symmetric-key-algorithm) key))
(setq result key)))))
(defun pgg-gpg-select-matching-key (message-keys secret-keys)
"Choose a key from MESSAGE-KEYS that matches one of the keys in SECRET-KEYS."
(loop for message-key in message-keys
for message-key-id = (and (equal (car message-key) 1)
(cdr (assq 'key-identifier
(cdr message-key))))
for key = (and message-key-id (pgg-lookup-key message-key-id 'encrypt))
when (and key (member key secret-keys)) return key))
(defun pgg-gpg-sign-region (start end &optional cleartext passphrase)
"Make detached signature from text between START and END."
(let* ((pgg-gpg-user-id (or pgg-gpg-user-id pgg-default-user-id))
(passphrase (or passphrase
(when (not (pgg-gpg-use-agent-p))
(pgg-read-passphrase
(format "GnuPG passphrase for %s: "
pgg-gpg-user-id)
pgg-gpg-user-id))))
(args
(append (list (if cleartext "--clearsign" "--detach-sign")
"--armor" "--batch" "--verbose"
"--local-user" pgg-gpg-user-id)
(if pgg-text-mode (list "--textmode"))))
(inhibit-read-only t)
buffer-read-only)
(pgg-gpg-process-region start end passphrase pgg-gpg-program args)
(with-current-buffer pgg-errors-buffer
;; Possibly cache passphrase under, e.g. "jas", for future sign.
(pgg-gpg-possibly-cache-passphrase passphrase pgg-gpg-user-id)
;; Possibly cache passphrase under, e.g. B565716F, for future decrypt.
(pgg-gpg-possibly-cache-passphrase passphrase))
(pgg-process-when-success)))
(defun pgg-gpg-verify-region (start end &optional signature)
"Verify region between START and END as the detached signature SIGNATURE."
(let ((args '("--batch" "--verify")))
(when (stringp signature)
(setq args (append args (list signature))))
(setq args (append args '("-")))
(pgg-gpg-process-region start end nil pgg-gpg-program args)
(with-current-buffer pgg-errors-buffer
(goto-char (point-min))
(while (re-search-forward "^gpg: \\(.*\\)\n" nil t)
(with-current-buffer pgg-output-buffer
(insert-buffer-substring pgg-errors-buffer
(match-beginning 1) (match-end 0)))
(delete-region (match-beginning 0) (match-end 0)))
(goto-char (point-min))
(re-search-forward "^\\[GNUPG:] GOODSIG\\>" nil t))))
(defun pgg-gpg-insert-key ()
"Insert public key at point."
(let* ((pgg-gpg-user-id (or pgg-gpg-user-id pgg-default-user-id))
(args (list "--batch" "--export" "--armor"
pgg-gpg-user-id)))
(pgg-gpg-process-region (point)(point) nil pgg-gpg-program args)
(insert-buffer-substring pgg-output-buffer)))
(defun pgg-gpg-snarf-keys-region (start end)
"Add all public keys in region between START and END to the keyring."
(let ((args '("--import" "--batch" "-")) status)
(pgg-gpg-process-region start end nil pgg-gpg-program args)
(set-buffer pgg-errors-buffer)
(goto-char (point-min))
(when (re-search-forward "^\\[GNUPG:] IMPORT_RES\\>" nil t)
(setq status (buffer-substring (match-end 0)
(progn (end-of-line)(point)))
status (vconcat (mapcar #'string-to-number (split-string status))))
(erase-buffer)
(insert (format "Imported %d key(s).
\tArmor contains %d key(s) [%d bad, %d old].\n"
(+ (aref status 2)
(aref status 10))
(aref status 0)
(aref status 1)
(+ (aref status 4)
(aref status 11)))
(if (zerop (aref status 9))
""
"\tSecret keys are imported.\n")))
(append-to-buffer pgg-output-buffer (point-min)(point-max))
(pgg-process-when-success)))
(defun pgg-gpg-update-agent ()
"Try to connet to gpg-agent and send UPDATESTARTUPTTY."
(if (fboundp 'make-network-process)
(let* ((agent-info (getenv "GPG_AGENT_INFO"))
(socket (and agent-info
(string-match "^\\([^:]*\\)" agent-info)
(match-string 1 agent-info)))
(conn (and socket
(make-network-process :name "gpg-agent-process"
:host 'local :family 'local
:service socket))))
(when (and conn (eq (process-status conn) 'open))
(process-send-string conn "UPDATESTARTUPTTY\n")
(delete-process conn)
t))
;; We can't check, so assume gpg-agent is up.
t))
(defun pgg-gpg-use-agent-p ()
"Return t if `pgg-gpg-use-agent' is t and gpg-agent is available."
(and pgg-gpg-use-agent (pgg-gpg-update-agent)))
(provide 'pgg-gpg)
;; arch-tag: 2aa5d5d8-93a0-4865-9312-33e29830e000
;;; pgg-gpg.el ends here