code.delx.au - gnu-emacs/blob - 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, 2007, 2008 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 3, 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 (eval-when-compile
  55   (require 'rx))
  56
  57 (defgroup tls nil
  58   "Transport Layer Security (TLS) parameters."
  59   :group 'comm)
  60
  61 (defcustom tls-end-of-info
  62   (rx
  63    (or
  64     ;; `openssl s_client` regexp
  65     (sequence
  66      ;; see ssl/ssl_txt.c lines 219--220
  67      line-start
  68      "    Verify return code: "
  69      (one-or-more not-newline)
  70      "\n"
  71      ;; according to apps/s_client.c line 1515 this is always the last
  72      ;; line that is printed by s_client before the real data
  73      "---\n")
  74     ;; `gnutls` regexp
  75     (sequence
  76      ;; see src/cli.c lines 721--
  77      (sequence line-start "- Simple Client Mode:\n")
  78      (zero-or-more
  79       (or
  80        "\n"                             ; ignore blank lines
  81        ;; XXX: we have no way of knowing if the STARTTLS handshake
  82        ;; sequence has completed successfully, because `gnutls` will
  83        ;; only report failure.
  84        (sequence line-start "\*\*\* Starting TLS handshake\n"))))))
  85   "Regexp matching end of TLS client informational messages.
  86 Client data stream begins after the last character matched by
  87 this.  The default matches `openssl s_client' (version 0.9.8c)
  88 and `gnutls-cli' (version 2.0.1) output."
  89   :version "22.2"
  90   :type 'regexp
  91   :group 'tls)
  92
  93 (defcustom tls-program '("gnutls-cli -p %p %h"
  94                          "gnutls-cli -p %p %h --protocols ssl3"
  95                          "openssl s_client -connect %h:%p -no_ssl2")
  96   "List of strings containing commands to start TLS stream to a host.
  97 Each entry in the list is tried until a connection is successful.
  98 %h is replaced with server hostname, %p with port to connect to.
  99 The program should read input on stdin and write output to
 100 stdout.  Also see `tls-success' for what the program should output
 101 after successful negotiation."
 102   :type '(repeat string)
 103   :version "22.1"
 104   :group 'tls)
 105
 106 (defcustom tls-process-connection-type nil
 107   "*Value for `process-connection-type' to use when starting TLS process."
 108   :version "22.1"
 109   :type 'boolean
 110   :group 'tls)
 111
 112 (defcustom tls-success "- Handshake was completed\\|SSL handshake has read "
 113   "*Regular expression indicating completed TLS handshakes.
 114 The default is what GNUTLS's \"gnutls-cli\" or OpenSSL's
 115 \"openssl s_client\" outputs."
 116   :version "22.1"
 117   :type 'regexp
 118   :group 'tls)
 119
 120 (defcustom tls-certtool-program (executable-find "certtool")
 121   "Name of  GnuTLS certtool.
 122 Used by `tls-certificate-information'."
 123   :version "22.1"
 124   :type 'string
 125   :group 'tls)
 126
 127 (defun tls-certificate-information (der)
 128   "Parse X.509 certificate in DER format into an assoc list."
 129   (let ((certificate (concat "-----BEGIN CERTIFICATE-----\n"
 130                              (base64-encode-string der)
 131                              "\n-----END CERTIFICATE-----\n"))
 132         (exit-code 0))
 133     (with-current-buffer (get-buffer-create " *certtool*")
 134       (erase-buffer)
 135       (insert certificate)
 136       (setq exit-code (condition-case ()
 137                           (call-process-region (point-min) (point-max)
 138                                                tls-certtool-program
 139                                                t (list (current-buffer) nil) t
 140                                                "--certificate-info")
 141                         (error -1)))
 142       (if (/= exit-code 0)
 143           nil
 144         (let ((vals nil))
 145           (goto-char (point-min))
 146           (while (re-search-forward "^\\([^:]+\\): \\(.*\\)" nil t)
 147             (push (cons (match-string 1) (match-string 2)) vals))
 148           (nreverse vals))))))
 149
 150 (defun open-tls-stream (name buffer host port)
 151   "Open a TLS connection for a port to a host.
 152 Returns a subprocess-object to represent the connection.
 153 Input and output work as for subprocesses; `delete-process' closes it.
 154 Args are NAME BUFFER HOST PORT.
 155 NAME is name for process.  It is modified if necessary to make it unique.
 156 BUFFER is the buffer (or buffer-name) to associate with the process.
 157  Process output goes at end of that buffer, unless you specify
 158  an output stream or filter function to handle the output.
 159  BUFFER may be also nil, meaning that this process is not associated
 160  with any buffer
 161 Third arg is name of the host to connect to, or its IP address.
 162 Fourth arg PORT is an integer specifying a port to connect to."
 163   (let ((cmds tls-program)
 164         (use-temp-buffer (null buffer))
 165         process cmd done)
 166     (if use-temp-buffer
 167         (setq buffer (generate-new-buffer " TLS")))
 168     (save-excursion
 169       (set-buffer buffer)
 170       (message "Opening TLS connection to `%s'..." host)
 171     (while (and (not done) (setq cmd (pop cmds)))
 172       (message "Opening TLS connection with `%s'..." cmd)
 173       (let ((process-connection-type tls-process-connection-type)
 174             response)
 175         (setq process (start-process
 176                        name buffer shell-file-name shell-command-switch
 177                        (format-spec
 178                         cmd
 179                         (format-spec-make
 180                          ?h host
 181                          ?p (if (integerp port)
 182                                 (int-to-string port)
 183                               port)))))
 184         (while (and process
 185                     (memq (process-status process) '(open run))
 186                     (progn
 187                       (goto-char (point-min))
 188                       (not (setq done (re-search-forward tls-success nil t)))))
 189           (unless (accept-process-output process 1)
 190             (sit-for 1)))
 191         (message "Opening TLS connection with `%s'...%s" cmd
 192                  (if done "done" "failed"))
 193         (if (not done)
 194             (delete-process process)
 195           ;; advance point to after all informational messages that
 196           ;; `openssl s_client' and `gnutls' print
 197           (let ((start-of-data nil))
 198             (while
 199                 (not (setq start-of-data
 200                            ;; the string matching `tls-end-of-info'
 201                            ;; might come in separate chunks from
 202                            ;; `accept-process-output', so start the
 203                            ;; search where `tls-success' ended
 204                            (save-excursion
 205                              (if (re-search-forward tls-end-of-info nil t)
 206                                  (match-end 0)))))
 207               (accept-process-output process 1))
 208             (if start-of-data
 209                 ;; move point to start of client data
 210                 (goto-char start-of-data)))
 211           (setq done process))))
 212     (message "Opening TLS connection to `%s'...%s"
 213              host (if done "done" "failed")))
 214     (when use-temp-buffer
 215       (if done (set-process-buffer process nil))
 216       (kill-buffer buffer))
 217     done))
 218
 219 (provide 'tls)
 220
 221 ;;; arch-tag: 5596d1c4-facc-4bc4-94a9-9863b928d7ac
 222 ;;; tls.el ends here