+++ /dev/null
-;;; smime.el --- S/MIME support library
-;; Copyright (c) 2000, 2001, 2003 Free Software Foundation, Inc.
-
-;; Author: Simon Josefsson <simon@josefsson.org>
-;; Keywords: SMIME X.509 PEM OpenSSL
-
-;; 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 2, 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; see the file COPYING. If not, write to the
-;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-;; Boston, MA 02111-1307, USA.
-
-;;; Commentary:
-
-;; This library perform S/MIME operations from within Emacs.
-;;
-;; Functions for fetching certificates from public repositories are
-;; provided, currently only from DNS. LDAP support (via EUDC) is planned.
-;;
-;; It uses OpenSSL (tested with version 0.9.5a and 0.9.6) for signing,
-;; encryption and decryption.
-;;
-;; Some general knowledge of S/MIME, X.509, PKCS#12, PEM etc is
-;; probably required to use this library in any useful way.
-;; Especially, don't expect this library to buy security for you. If
-;; you don't understand what you are doing, you're as likely to lose
-;; security than gain any by using this library.
-;;
-;; This library is not intended to provide a "raw" API for S/MIME,
-;; PKCSx or similar, it's intended to perform common operations
-;; done on messages encoded in these formats. The terminology chosen
-;; reflect this.
-;;
-;; The home of this file is in Gnus CVS, but also available from
-;; http://josefsson.org/smime.html.
-
-;;; Quick introduction:
-
-;; Get your S/MIME certificate from VeriSign or someplace. I used
-;; Netscape to generate the key and certificate request and stuff, and
-;; Netscape can export the key into PKCS#12 format.
-;;
-;; Enter OpenSSL. To be able to use this library, it need to have the
-;; SMIME key readable in PEM format. OpenSSL is used to convert the
-;; key:
-;;
-;; $ openssl pkcs12 -in mykey.p12 -clcerts -nodes > mykey.pem
-;; ...
-;;
-;; Now, use M-x customize-variable smime-keys and add mykey.pem as
-;; a key.
-;;
-;; Now you should be able to sign messages! Create a buffer and write
-;; something and run M-x smime-sign-buffer RET RET and you should see
-;; your message MIME armoured and a signature. Encryption, M-x
-;; smime-encrypt-buffer, should also work.
-;;
-;; To be able to verify messages you need to build up trust with
-;; someone. Perhaps you trust the CA that issued your certificate, at
-;; least I did, so I export it's certificates from my PKCS#12
-;; certificate with:
-;;
-;; $ openssl pkcs12 -in mykey.p12 -cacerts -nodes > cacert.pem
-;; ...
-;;
-;; Now, use M-x customize-variable smime-CAs and add cacert.pem as a
-;; CA certificate.
-;;
-;; You should now be able to sign messages, and even verify messages
-;; sent by others that use the same CA as you.
-
-;; Bugs:
-;;
-;; Don't complain that this package doesn't do encrypted PEM files,
-;; submit a patch instead. I store my keys in a safe place, so I
-;; didn't need the encryption. Also, programming was made easier by
-;; that decision. One might think that this even influenced were I
-;; store my keys, and one would probably be right. :-)
-;;
-;; Update: Mathias Herberts sent the patch. However, it uses
-;; environment variables to pass the password to OpenSSL, which is
-;; slightly insecure. Hence a new todo: use a better -passin method.
-;;
-;; Cache password for e.g. 1h
-;;
-;; Suggestions and comments are appreciated, mail me at simon@josefsson.org.
-
-;; begin rant
-;;
-;; I would include pointers to introductory text on concepts used in
-;; this library here, but the material I've read are so horrible I
-;; don't want to recomend them.
-;;
-;; Why can't someone write a simple introduction to all this stuff?
-;; Until then, much of this resemble security by obscurity.
-;;
-;; Also, I'm not going to mention anything about the wonders of
-;; cryptopolitics. Oops, I just did.
-;;
-;; end rant
-
-;;; Revision history:
-
-;; 2000-06-05 initial version, committed to Gnus CVS contrib/
-;; 2000-10-28 retrieve certificates via DNS CERT RRs
-;; 2001-10-14 posted to gnu.emacs.sources
-
-;;; Code:
-
-(require 'dig)
-(eval-when-compile (require 'cl))
-
-(defgroup smime nil
- "S/MIME configuration.")
-
-(defcustom smime-keys nil
- "*Map mail addresses to a file containing Certificate (and private key).
-The file is assumed to be in PEM format. You can also associate additional
-certificates to be sent with every message to each address."
- :type '(repeat (list (string :tag "Mail address")
- (file :tag "File name")
- (repeat :tag "Additional certificate files"
- (file :tag "File name"))))
- :group 'smime)
-
-(defcustom smime-CA-directory nil
- "*Directory containing certificates for CAs you trust.
-Directory should contain files (in PEM format) named to the X.509
-hash of the certificate. This can be done using OpenSSL such as:
-
-$ ln -s ca.pem `openssl x509 -noout -hash -in ca.pem`.0
-
-where `ca.pem' is the file containing a PEM encoded X.509 CA
-certificate."
- :type '(choice (const :tag "none" nil)
- directory)
- :group 'smime)
-
-(defcustom smime-CA-file nil
- "*Files containing certificates for CAs you trust.
-File should contain certificates in PEM format."
- :type '(choice (const :tag "none" nil)
- file)
- :group 'smime)
-
-(defcustom smime-certificate-directory "~/Mail/certs/"
- "*Directory containing other people's certificates.
-It should contain files named to the X.509 hash of the certificate,
-and the files themself should be in PEM format."
-;The S/MIME library provide simple functionality for fetching
-;certificates into this directory, so there is no need to populate it
-;manually.
- :type 'directory
- :group 'smime)
-
-(defcustom smime-openssl-program
- (and (condition-case ()
- (eq 0 (call-process "openssl" nil nil nil "version"))
- (error nil))
- "openssl")
- "*Name of OpenSSL binary."
- :type 'string
- :group 'smime)
-
-;; OpenSSL option to select the encryption cipher
-
-(defcustom smime-encrypt-cipher "-des3"
- "*Cipher algorithm used for encryption."
- :type '(choice (const :tag "Triple DES" "-des3")
- (const :tag "DES" "-des")
- (const :tag "RC2 40 bits" "-rc2-40")
- (const :tag "RC2 64 bits" "-rc2-64")
- (const :tag "RC2 128 bits" "-rc2-128"))
- :group 'smime)
-
-(defcustom smime-crl-check nil
- "*Check revocation status of signers certificate using CRLs.
-Enabling this will have OpenSSL check the signers certificate
-against a certificate revocation list (CRL).
-
-For this to work the CRL must be up-to-date and since they are
-normally updated quite often (ie. several times a day) you
-probably need some tool to keep them up-to-date. Unfortunately
-Gnus cannot do this for you.
-
-The CRL should either be appended (in PEM format) to your
-`smime-CA-file' or be located in a file (also in PEM format) in
-your `smime-certificate-directory' named to the X.509 hash of the
-certificate with .r0 as file name extension.
-
-At least OpenSSL version 0.9.7 is required for this to work."
- :type '(choice (const :tag "No check" nil)
- (const :tag "Check certificate" "-crl_check")
- (const :tag "Check certificate chain" "-crl_check_all"))
- :group 'smime)
-
-(defcustom smime-dns-server nil
- "*DNS server to query certificates from.
-If nil, use system defaults."
- :type '(choice (const :tag "System defaults")
- string)
- :group 'smime)
-
-(defvar smime-details-buffer "*OpenSSL output*")
-
-;; Use mm-util?
-(eval-and-compile
- (defalias 'smime-make-temp-file
- (if (fboundp 'make-temp-file)
- 'make-temp-file
- (lambda (prefix &optional dir-flag) ;; Simple implementation
- (expand-file-name
- (make-temp-name prefix)
- (if (fboundp 'temp-directory)
- (temp-directory)
- temporary-file-directory))))))
-
-;; Password dialog function
-
-(defun smime-ask-passphrase ()
- "Asks the passphrase to unlock the secret key."
- (let ((passphrase
- (read-passwd
- "Passphrase for secret key (RET for no passphrase): ")))
- (if (string= passphrase "")
- nil
- passphrase)))
-
-;; OpenSSL wrappers.
-
-(defun smime-call-openssl-region (b e buf &rest args)
- (case (apply 'call-process-region b e smime-openssl-program nil buf nil args)
- (0 t)
- (1 (message "OpenSSL: An error occurred parsing the command options.") nil)
- (2 (message "OpenSSL: One of the input files could not be read.") nil)
- (3 (message "OpenSSL: An error occurred creating the PKCS#7 file or when reading the MIME message.") nil)
- (4 (message "OpenSSL: An error occurred decrypting or verifying the message.") nil)
- (t (error "Unknown OpenSSL exitcode") nil)))
-
-(defun smime-make-certfiles (certfiles)
- (if certfiles
- (append (list "-certfile" (expand-file-name (car certfiles)))
- (smime-make-certfiles (cdr certfiles)))))
-
-;; Sign+encrypt region
-
-(defun smime-sign-region (b e keyfile)
- "Sign region with certified key in KEYFILE.
-If signing fails, the buffer is not modified. Region is assumed to
-have proper MIME tags. KEYFILE is expected to contain a PEM encoded
-private key and certificate as its car, and a list of additional
-certificates to include in its caar. If no additional certificates is
-included, KEYFILE may be the file containing the PEM encoded private
-key and certificate itself."
- (smime-new-details-buffer)
- (let ((keyfile (or (car-safe keyfile) keyfile))
- (certfiles (and (cdr-safe keyfile) (cadr keyfile)))
- (buffer (generate-new-buffer (generate-new-buffer-name " *smime*")))
- (passphrase (smime-ask-passphrase))
- (tmpfile (smime-make-temp-file "smime")))
- (if passphrase
- (setenv "GNUS_SMIME_PASSPHRASE" passphrase))
- (prog1
- (when (prog1
- (apply 'smime-call-openssl-region b e (list buffer tmpfile)
- "smime" "-sign" "-signer" (expand-file-name keyfile)
- (append
- (smime-make-certfiles certfiles)
- (if passphrase
- (list "-passin" "env:GNUS_SMIME_PASSPHRASE"))))
- (if passphrase
- (setenv "GNUS_SMIME_PASSPHRASE" "" t))
- (with-current-buffer smime-details-buffer
- (insert-file-contents tmpfile)
- (delete-file tmpfile)))
- (delete-region b e)
- (insert-buffer-substring buffer)
- (goto-char b)
- (when (looking-at "^MIME-Version: 1.0$")
- (delete-region (point) (progn (forward-line 1) (point))))
- t)
- (with-current-buffer smime-details-buffer
- (goto-char (point-max))
- (insert-buffer-substring buffer))
- (kill-buffer buffer))))
-
-(defun smime-encrypt-region (b e certfiles)
- "Encrypt region for recipients specified in CERTFILES.
-If encryption fails, the buffer is not modified. Region is assumed to
-have proper MIME tags. CERTFILES is a list of filenames, each file
-is expected to contain of a PEM encoded certificate."
- (smime-new-details-buffer)
- (let ((buffer (generate-new-buffer (generate-new-buffer-name " *smime*")))
- (tmpfile (smime-make-temp-file "smime")))
- (prog1
- (when (prog1
- (apply 'smime-call-openssl-region b e (list buffer tmpfile)
- "smime" "-encrypt" smime-encrypt-cipher
- (mapcar 'expand-file-name certfiles))
- (with-current-buffer smime-details-buffer
- (insert-file-contents tmpfile)
- (delete-file tmpfile)))
- (delete-region b e)
- (insert-buffer-substring buffer)
- (goto-char b)
- (when (looking-at "^MIME-Version: 1.0$")
- (delete-region (point) (progn (forward-line 1) (point))))
- t)
- (with-current-buffer smime-details-buffer
- (goto-char (point-max))
- (insert-buffer-substring buffer))
- (kill-buffer buffer))))
-
-;; Sign+encrypt buffer
-
-(defun smime-sign-buffer (&optional keyfile buffer)
- "S/MIME sign BUFFER with key in KEYFILE.
-KEYFILE should contain a PEM encoded key and certificate."
- (interactive)
- (with-current-buffer (or buffer (current-buffer))
- (smime-sign-region
- (point-min) (point-max)
- (if keyfile
- keyfile
- (smime-get-key-with-certs-by-email
- (completing-read
- (concat "Sign using which key? "
- (if smime-keys (concat "(default " (caar smime-keys) ") ")
- ""))
- smime-keys nil nil (car-safe (car-safe smime-keys))))))))
-
-(defun smime-encrypt-buffer (&optional certfiles buffer)
- "S/MIME encrypt BUFFER for recipients specified in CERTFILES.
-CERTFILES is a list of filenames, each file is expected to consist of
-a PEM encoded key and certificate. Uses current buffer if BUFFER is
-nil."
- (interactive)
- (with-current-buffer (or buffer (current-buffer))
- (smime-encrypt-region
- (point-min) (point-max)
- (or certfiles
- (list (read-file-name "Recipient's S/MIME certificate: "
- smime-certificate-directory nil))))))
-
-;; Verify+decrypt region
-
-(defun smime-verify-region (b e)
- "Verify S/MIME message in region between B and E.
-Returns non-nil on success.
-Any details (stdout and stderr) are left in the buffer specified by
-`smime-details-buffer'."
- (smime-new-details-buffer)
- (let ((CAs (append (if smime-CA-file
- (list "-CAfile"
- (expand-file-name smime-CA-file)))
- (if smime-CA-directory
- (list "-CApath"
- (expand-file-name smime-CA-directory))))))
- (unless CAs
- (error "No CA configured"))
- (if smime-crl-check
- (add-to-list 'CAs smime-crl-check))
- (if (apply 'smime-call-openssl-region b e (list smime-details-buffer t)
- "smime" "-verify" "-out" "/dev/null" CAs)
- t
- (insert-buffer-substring smime-details-buffer)
- nil)))
-
-(defun smime-noverify-region (b e)
- "Verify integrity of S/MIME message in region between B and E.
-Returns non-nil on success.
-Any details (stdout and stderr) are left in the buffer specified by
-`smime-details-buffer'."
- (smime-new-details-buffer)
- (if (apply 'smime-call-openssl-region b e (list smime-details-buffer t)
- "smime" "-verify" "-noverify" "-out" '("/dev/null"))
- t
- (insert-buffer-substring smime-details-buffer)
- nil))
-
-(eval-when-compile
- (defvar from))
-
-(defun smime-decrypt-region (b e keyfile)
- "Decrypt S/MIME message in region between B and E with key in KEYFILE.
-On success, replaces region with decrypted data and return non-nil.
-Any details (stderr on success, stdout and stderr on error) are left
-in the buffer specified by `smime-details-buffer'."
- (smime-new-details-buffer)
- (let ((buffer (generate-new-buffer (generate-new-buffer-name " *smime*")))
- CAs (passphrase (smime-ask-passphrase))
- (tmpfile (smime-make-temp-file "smime")))
- (if passphrase
- (setenv "GNUS_SMIME_PASSPHRASE" passphrase))
- (if (prog1
- (apply 'smime-call-openssl-region b e
- (list buffer tmpfile)
- "smime" "-decrypt" "-recip" (expand-file-name keyfile)
- (if passphrase
- (list "-passin" "env:GNUS_SMIME_PASSPHRASE")))
- (if passphrase
- (setenv "GNUS_SMIME_PASSPHRASE" "" t))
- (with-current-buffer smime-details-buffer
- (insert-file-contents tmpfile)
- (delete-file tmpfile)))
- (progn
- (delete-region b e)
- (when (boundp 'from)
- ;; `from' is dynamically bound in mm-dissect.
- (insert "From: " from "\n"))
- (insert-buffer-substring buffer)
- (kill-buffer buffer)
- t)
- (with-current-buffer smime-details-buffer
- (insert-buffer-substring buffer))
- (kill-buffer buffer)
- (delete-region b e)
- (insert-buffer-substring smime-details-buffer)
- nil)))
-
-;; Verify+Decrypt buffer
-
-(defun smime-verify-buffer (&optional buffer)
- "Verify integrity of S/MIME message in BUFFER.
-Uses current buffer if BUFFER is nil. Returns non-nil on success.
-Any details (stdout and stderr) are left in the buffer specified by
-`smime-details-buffer'."
- (interactive)
- (with-current-buffer (or buffer (current-buffer))
- (smime-verify-region (point-min) (point-max))))
-
-(defun smime-noverify-buffer (&optional buffer)
- "Verify integrity of S/MIME message in BUFFER.
-Does NOT verify validity of certificate (only message integrity).
-Uses current buffer if BUFFER is nil. Returns non-nil on success.
-Any details (stdout and stderr) are left in the buffer specified by
-`smime-details-buffer'."
- (interactive)
- (with-current-buffer (or buffer (current-buffer))
- (smime-noverify-region (point-min) (point-max))))
-
-(defun smime-decrypt-buffer (&optional buffer keyfile)
- "Decrypt S/MIME message in BUFFER using KEYFILE.
-Uses current buffer if BUFFER is nil, and query user of KEYFILE if it's nil.
-On success, replaces data in buffer and return non-nil.
-Any details (stderr on success, stdout and stderr on error) are left
-in the buffer specified by `smime-details-buffer'."
- (interactive)
- (with-current-buffer (or buffer (current-buffer))
- (smime-decrypt-region
- (point-min) (point-max)
- (expand-file-name
- (or keyfile
- (smime-get-key-by-email
- (completing-read
- (concat "Decipher using which key? "
- (if smime-keys (concat "(default " (caar smime-keys) ") ")
- ""))
- smime-keys nil nil (car-safe (car-safe smime-keys)))))))))
-
-;; Various operations
-
-(defun smime-new-details-buffer ()
- (with-current-buffer (get-buffer-create smime-details-buffer)
- (erase-buffer)))
-
-(defun smime-pkcs7-region (b e)
- "Convert S/MIME message between points B and E into a PKCS7 message."
- (smime-new-details-buffer)
- (when (smime-call-openssl-region b e smime-details-buffer "smime" "-pk7out")
- (delete-region b e)
- (insert-buffer-substring smime-details-buffer)
- t))
-
-(defun smime-pkcs7-certificates-region (b e)
- "Extract any certificates enclosed in PKCS7 message between points B and E."
- (smime-new-details-buffer)
- (when (smime-call-openssl-region
- b e smime-details-buffer "pkcs7" "-print_certs" "-text")
- (delete-region b e)
- (insert-buffer-substring smime-details-buffer)
- t))
-
-(defun smime-pkcs7-email-region (b e)
- "Get email addresses contained in certificate between points B and E.
-A string or a list of strings is returned."
- (smime-new-details-buffer)
- (when (smime-call-openssl-region
- b e smime-details-buffer "x509" "-email" "-noout")
- (delete-region b e)
- (insert-buffer-substring smime-details-buffer)
- t))
-
-;; Utility functions
-
-(defun smime-get-certfiles (keyfile keys)
- (if keys
- (let ((curkey (car keys))
- (otherkeys (cdr keys)))
- (if (string= keyfile (cadr curkey))
- (caddr curkey)
- (smime-get-certfiles keyfile otherkeys)))))
-
-(defun smime-buffer-as-string-region (b e)
- "Return each line in region between B and E as a list of strings."
- (save-excursion
- (goto-char b)
- (let (res)
- (while (< (point) e)
- (let ((str (buffer-substring (point) (point-at-eol))))
- (unless (string= "" str)
- (push str res)))
- (forward-line))
- res)))
-
-;; Find certificates
-
-(defun smime-mail-to-domain (mailaddr)
- (if (string-match "@" mailaddr)
- (replace-match "." 'fixedcase 'literal mailaddr)
- mailaddr))
-
-(defun smime-cert-by-dns (mail)
- (let* ((dig-dns-server smime-dns-server)
- (digbuf (dig-invoke (smime-mail-to-domain mail) "cert" nil nil "+vc"))
- (retbuf (generate-new-buffer (format "*certificate for %s*" mail)))
- (certrr (with-current-buffer digbuf
- (dig-extract-rr (smime-mail-to-domain mail) "cert")))
- (cert (and certrr (dig-rr-get-pkix-cert certrr))))
- (if cert
- (with-current-buffer retbuf
- (insert "-----BEGIN CERTIFICATE-----\n")
- (let ((i 0) (len (length cert)))
- (while (> (- len 64) i)
- (insert (substring cert i (+ i 64)) "\n")
- (setq i (+ i 64)))
- (insert (substring cert i len) "\n"))
- (insert "-----END CERTIFICATE-----\n"))
- (kill-buffer retbuf)
- (setq retbuf nil))
- (kill-buffer digbuf)
- retbuf))
-
-;; User interface.
-
-(defvar smime-buffer "*SMIME*")
-
-(defvar smime-mode-map nil)
-(put 'smime-mode 'mode-class 'special)
-
-(unless smime-mode-map
- (setq smime-mode-map (make-sparse-keymap))
- (suppress-keymap smime-mode-map)
-
- (define-key smime-mode-map "q" 'smime-exit)
- (define-key smime-mode-map "f" 'smime-certificate-info))
-
-(defun smime-mode ()
- "Major mode for browsing, viewing and fetching certificates.
-
-All normal editing commands are switched off.
-\\<smime-mode-map>
-
-The following commands are available:
-
-\\{smime-mode-map}"
- (interactive)
- (kill-all-local-variables)
- (setq major-mode 'smime-mode)
- (setq mode-name "SMIME")
- (setq mode-line-process nil)
- (use-local-map smime-mode-map)
- (buffer-disable-undo)
- (setq truncate-lines t)
- (setq buffer-read-only t))
-
-(defun smime-certificate-info (certfile)
- (interactive "fCertificate file: ")
- (let ((buffer (get-buffer-create (format "*certificate %s*" certfile))))
- (switch-to-buffer buffer)
- (erase-buffer)
- (call-process smime-openssl-program nil buffer 'display
- "x509" "-in" (expand-file-name certfile) "-text")
- (fundamental-mode)
- (set-buffer-modified-p nil)
- (toggle-read-only t)
- (goto-char (point-min))))
-
-(defun smime-draw-buffer ()
- (with-current-buffer smime-buffer
- (let (buffer-read-only)
- (erase-buffer)
- (insert "\nYour keys:\n")
- (dolist (key smime-keys)
- (insert
- (format "\t\t%s: %s\n" (car key) (cadr key))))
- (insert "\nTrusted Certificate Authoritys:\n")
- (insert "\nKnown Certificates:\n"))))
-
-(defun smime ()
- "Go to the SMIME buffer."
- (interactive)
- (unless (get-buffer smime-buffer)
- (save-excursion
- (set-buffer (get-buffer-create smime-buffer))
- (smime-mode)))
- (smime-draw-buffer)
- (switch-to-buffer smime-buffer))
-
-(defun smime-exit ()
- "Quit the S/MIME buffer."
- (interactive)
- (kill-buffer (current-buffer)))
-
-;; Other functions
-
-(defun smime-get-key-by-email (email)
- (cadr (assoc email smime-keys)))
-
-(defun smime-get-key-with-certs-by-email (email)
- (cdr (assoc email smime-keys)))
-
-(provide 'smime)
-
-;;; smime.el ends here
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