code.delx.au - gnu-emacs/blob - lisp/net/gnutls.el

   1 ;;; gnutls.el --- Support SSL and TLS connections through GnuTLS
   2 ;; Copyright (C) 2010 Free Software Foundation, Inc.
   3
   4 ;; Author: Ted Zlatanov <tzz@lifelogs.com>
   5 ;; Keywords: comm, tls, ssl, encryption
   6 ;; Originally-By: Simon Josefsson (See http://josefsson.org/emacs-security/)
   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 ;; This package provides language bindings for the GnuTLS library
  26 ;; using the corresponding core functions in gnutls.c.
  27
  28 ;; Simple test:
  29 ;;
  30 ;; (setq jas (open-ssl-stream "ssl" (current-buffer) "www.pdc.kth.se" 443))
  31 ;; (process-send-string jas "GET /\r\n\r\n")
  32
  33 ;;; Code:
  34
  35 (defun open-ssl-stream (name buffer host service)
  36   "Open a SSL connection for a service to a host.
  37 Returns a subprocess-object to represent the connection.
  38 Input and output work as for subprocesses; `delete-process' closes it.
  39 Args are NAME BUFFER HOST SERVICE.
  40 NAME is name for process.  It is modified if necessary to make it unique.
  41 BUFFER is the buffer (or `buffer-name') to associate with the process.
  42  Process output goes at end of that buffer, unless you specify
  43  an output stream or filter function to handle the output.
  44  BUFFER may be also nil, meaning that this process is not associated
  45  with any buffer
  46 Third arg is name of the host to connect to, or its IP address.
  47 Fourth arg SERVICE is name of the service desired, or an integer
  48 specifying a port number to connect to."
  49   (let ((proc (open-network-stream name buffer host service)))
  50     (starttls-negotiate proc nil 'gnutls-x509pki)))
  51
  52 ;; (open-ssl-stream "tls" "tls-buffer" "yourserver.com" "https")
  53 (defun starttls-negotiate (proc &optional priority-string
  54                                 credentials credentials-file)
  55   "Negotiate a SSL or TLS connection.
  56 PROC is the process returned by `starttls-open-stream'.
  57 PRIORITY-STRING is as per the GnuTLS docs.
  58 CREDENTIALS is `gnutls-x509pki' or `gnutls-anon'.
  59 CREDENTIALS-FILE is a filename with meaning dependent on CREDENTIALS."
  60   (let* ((credentials (or credentials 'gnutls-x509pki))
  61          (credentials-file (or credentials-file
  62                                "/etc/ssl/certs/ca-certificates.crt"
  63                                ;"/etc/ssl/certs/ca.pem"
  64                                ))
  65
  66          (priority-string (or priority-string
  67                               (cond
  68                                ((eq credentials 'gnutls-anon)
  69                                 "NORMAL:+ANON-DH:!ARCFOUR-128")
  70                                ((eq credentials 'gnutls-x509pki)
  71                                 "NORMAL"))))
  72          ret)
  73
  74     (gnutls-message-maybe
  75      (setq ret (gnutls-boot proc priority-string credentials credentials-file))
  76      "boot: %s")
  77
  78     (when (gnutls-errorp ret)
  79       (error "Could not boot GnuTLS for this process"));
  80
  81     (let ((ret 'gnutls-e-again)
  82           (n 25000))
  83       (while (and (not (gnutls-error-fatalp ret))
  84                   (> n 0))
  85         (setq n (1- n))
  86         (gnutls-message-maybe
  87          (setq ret (gnutls-handshake proc))
  88          "handshake: %s")
  89         ;(debug "handshake ret" ret (gnutls-error-string ret)))
  90         )
  91       (if (gnutls-errorp ret)
  92           (progn
  93             (message "Ouch, error return %s (%s)"
  94                      ret (gnutls-error-string ret))
  95             (setq proc nil))
  96         (message "Handshake complete %s." ret)))
  97      proc))
  98
  99 (defun starttls-open-stream (name buffer host service)
 100   "Open a TLS connection for a service to a host.
 101 Returns a subprocess-object to represent the connection.
 102 Input and output work as for subprocesses; `delete-process' closes it.
 103 Args are NAME BUFFER HOST SERVICE.
 104 NAME is name for process.  It is modified if necessary to make it unique.
 105 BUFFER is the buffer (or `buffer-name') to associate with the process.
 106  Process output goes at end of that buffer, unless you specify
 107  an output stream or filter function to handle the output.
 108  BUFFER may be also nil, meaning that this process is not associated
 109  with any buffer
 110 Third arg is name of the host to connect to, or its IP address.
 111 Fourth arg SERVICE is name of the service desired, or an integer
 112 specifying a port number to connect to."
 113   (open-network-stream name buffer host service))
 114
 115 (defun gnutls-message-maybe (doit format &rest params)
 116   "When DOIT, message with the caller name followed by FORMAT on PARAMS."
 117   ;; (apply 'debug format (or params '(nil)))
 118   (when (gnutls-errorp doit)
 119     (message "%s: (err=[%s] %s) %s"
 120              "gnutls.el"
 121              doit (gnutls-error-string doit)
 122              (apply 'format format (or params '(nil))))))
 123
 124 (provide 'ssl)
 125 (provide 'gnutls)
 126 (provide 'starttls)
 127
 128 ;;; gnutls.el ends here