lisp/net/tls.el

   1 ;;; tls.el --- TLS/SSL support via wrapper around GnuTLS
   2
   3 ;; Copyright (C) 1996, 1997, 1998, 1999, 2002, 2003, 2004,
   4 ;;   2005, 2006 Free Software Foundation, Inc.
   5
   6 ;; Author: Simon Josefsson <simon@josefsson.org>
   7 ;; Keywords: comm, tls, gnutls, ssl
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software; you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation; either version 2, or (at your option)
  14 ;; any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  23 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  24 ;; Boston, MA 02110-1301, USA.
  25
  26 ;;; Commentary:
  27
  28 ;; This package implements a simple wrapper around "gnutls-cli" to
  29 ;; make Emacs support TLS/SSL.
  30 ;;
  31 ;; Usage is the same as `open-network-stream', i.e.:
  32 ;;
  33 ;; (setq tmp (open-tls-stream "test" (current-buffer) "news.mozilla.org" 563))
  34 ;; ...
  35 ;; #<process test>
  36 ;; (process-send-string tmp "mode reader\n")
  37 ;; 200 secnews.netscape.com Netscape-Collabra/3.52 03615 NNRP ready ...
  38 ;; nil
  39 ;; (process-send-string tmp "quit\n")
  40 ;; 205
  41 ;; nil
  42
  43 ;; To use this package as a replacement for ssl.el by William M. Perry
  44 ;; <wmperry@cs.indiana.edu>, you need to evaluate the following:
  45 ;;
  46 ;; (defalias 'open-ssl-stream 'open-tls-stream)
  47
  48 ;;; Code:
  49
  50 (eval-and-compile
  51   (autoload 'format-spec "format-spec")
  52   (autoload 'format-spec-make "format-spec"))
  53
  54 (defgroup tls nil
  55   "Transport Layer Security (TLS) parameters."
  56   :group 'comm)
  57
  58 (defcustom tls-program '("gnutls-cli -p %p %h"
  59                          "gnutls-cli -p %p %h --protocols ssl3"
  60                          "openssl s_client -connect %h:%p -no_ssl2")
  61   "List of strings containing commands to start TLS stream to a host.
  62 Each entry in the list is tried until a connection is successful.
  63 %s is replaced with server hostname, %p with port to connect to.
  64 The program should read input on stdin and write output to
  65 stdout.  Also see `tls-success' for what the program should output
  66 after successful negotiation."
  67   :type '(repeat string)
  68   :version "22.1"
  69   :group 'tls)
  70
  71 (defcustom tls-process-connection-type nil
  72   "*Value for `process-connection-type' to use when starting TLS process."
  73   :version "22.1"
  74   :type 'boolean
  75   :group 'tls)
  76
  77 (defcustom tls-success "- Handshake was completed\\|SSL handshake has read "
  78   "*Regular expression indicating completed TLS handshakes.
  79 The default is what GNUTLS's \"gnutls-cli\" or OpenSSL's
  80 \"openssl s_client\" outputs."
  81   :version "22.1"
  82   :type 'regexp
  83   :group 'tls)
  84
  85 (defcustom tls-certtool-program (executable-find "certtool")
  86   "Name of  GnuTLS certtool.
  87 Used by `tls-certificate-information'."
  88   :version "22.1"
  89   :type '(repeat string)
  90   :group 'tls)
  91
  92 (defun tls-certificate-information (der)
  93   "Parse X.509 certificate in DER format into an assoc list."
  94   (let ((certificate (concat "-----BEGIN CERTIFICATE-----\n"
  95                              (base64-encode-string der)
  96                              "\n-----END CERTIFICATE-----\n"))
  97         (exit-code 0))
  98     (with-current-buffer (get-buffer-create " *certtool*")
  99       (erase-buffer)
 100       (insert certificate)
 101       (setq exit-code (condition-case ()
 102                           (call-process-region (point-min) (point-max)
 103                                                tls-certtool-program
 104                                                t (list (current-buffer) nil) t
 105                                                "--certificate-info")
 106                         (error -1)))
 107       (if (/= exit-code 0)
 108           nil
 109         (let ((vals nil))
 110           (goto-char (point-min))
 111           (while (re-search-forward "^\\([^:]+\\): \\(.*\\)" nil t)
 112             (push (cons (match-string 1) (match-string 2)) vals))
 113           (nreverse vals))))))
 114
 115 (defun open-tls-stream (name buffer host port)
 116   "Open a TLS connection for a port to a host.
 117 Returns a subprocess-object to represent the connection.
 118 Input and output work as for subprocesses; `delete-process' closes it.
 119 Args are NAME BUFFER HOST PORT.
 120 NAME is name for process.  It is modified if necessary to make it unique.
 121 BUFFER is the buffer (or buffer-name) to associate with the process.
 122  Process output goes at end of that buffer, unless you specify
 123  an output stream or filter function to handle the output.
 124  BUFFER may be also nil, meaning that this process is not associated
 125  with any buffer
 126 Third arg is name of the host to connect to, or its IP address.
 127 Fourth arg PORT is an integer specifying a port to connect to."
 128   (let ((cmds tls-program) cmd done)
 129     (message "Opening TLS connection to `%s'..." host)
 130     (while (and (not done) (setq cmd (pop cmds)))
 131       (message "Opening TLS connection with `%s'..." cmd)
 132       (let* ((process-connection-type tls-process-connection-type)
 133              (process (start-process
 134                        name buffer shell-file-name shell-command-switch
 135                        (format-spec
 136                         cmd
 137                         (format-spec-make
 138                          ?h host
 139                          ?p (if (integerp port)
 140                                 (int-to-string port)
 141                               port)))))
 142              response)
 143         (while (and process
 144                     (memq (process-status process) '(open run))
 145                     (save-excursion
 146                       (set-buffer buffer) ;; XXX "blue moon" nntp.el bug
 147                       (goto-char (point-min))
 148                       (not (setq done (re-search-forward tls-success nil t)))))
 149           (accept-process-output process 1)
 150           (sit-for 1))
 151         (message "Opening TLS connection with `%s'...%s" cmd
 152                  (if done "done" "failed"))
 153         (if done
 154             (setq done process)
 155           (delete-process process))))
 156     (message "Opening TLS connection to `%s'...%s"
 157              host (if done "done" "failed"))
 158     done))
 159
 160 (provide 'tls)
 161
 162 ;;; arch-tag: 5596d1c4-facc-4bc4-94a9-9863b928d7ac
 163 ;;; tls.el ends here