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1 | ;;; tls.el --- TLS/SSL support via wrapper around GnuTLS |
2 | ||
5fd6d89f | 3 | ;; Copyright (C) 1996, 1997, 1998, 1999, 2002, 2003, 2004, |
2f043267 | 4 | ;; 2005, 2006, 2007, 2008 Free Software Foundation, Inc. |
01b2d1dd SJ |
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 | |
ceaeecb0 | 13 | ;; the Free Software Foundation; either version 3, or (at your option) |
01b2d1dd SJ |
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 | |
3a35cf56 LK |
23 | ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, |
24 | ;; Boston, MA 02110-1301, USA. | |
01b2d1dd SJ |
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 | ||
59c95dc2 | 58 | (defcustom tls-end-of-info |
cd6db47c GM |
59 | (concat |
60 | "\\(" | |
61 | ;; `openssl s_client' regexp. See ssl/ssl_txt.c lines 219-220. | |
62 | ;; According to apps/s_client.c line 1515 `---' is always the last | |
63 | ;; line that is printed by s_client before the real data. | |
64 | "^ Verify return code: .+\n---\n\\|" | |
65 | ;; `gnutls' regexp. See src/cli.c lines 721-. | |
66 | "^- Simple Client Mode:\n" | |
67 | "\\(\n\\|" ; ignore blank lines | |
2cddada0 | 68 | ;; According to GnuTLS v2.1.5 src/cli.c lines 640-650 and 705-715 |
7b63c073 | 69 | ;; in `main' the handshake will start after this message. If the |
2cddada0 | 70 | ;; handshake fails, the programs will abort. |
cd6db47c GM |
71 | "^\\*\\*\\* Starting TLS handshake\n\\)*" |
72 | "\\)") | |
59c95dc2 GM |
73 | "Regexp matching end of TLS client informational messages. |
74 | Client data stream begins after the last character matched by | |
75 | this. The default matches `openssl s_client' (version 0.9.8c) | |
76 | and `gnutls-cli' (version 2.0.1) output." | |
77 | :version "22.2" | |
78 | :type 'regexp | |
79 | :group 'tls) | |
80 | ||
01b2d1dd | 81 | (defcustom tls-program '("gnutls-cli -p %p %h" |
3031d8b0 MB |
82 | "gnutls-cli -p %p %h --protocols ssl3" |
83 | "openssl s_client -connect %h:%p -no_ssl2") | |
01b2d1dd SJ |
84 | "List of strings containing commands to start TLS stream to a host. |
85 | Each entry in the list is tried until a connection is successful. | |
4a3c7686 | 86 | %h is replaced with server hostname, %p with port to connect to. |
01b2d1dd | 87 | The program should read input on stdin and write output to |
b890d447 MB |
88 | stdout. |
89 | ||
90 | See `tls-checktrust' on how to check trusted root certs. | |
91 | ||
92 | Also see `tls-success' for what the program should output after | |
93 | successful negotiation." | |
94 | :type | |
95 | '(choice | |
96 | (list :tag "Choose commands" | |
97 | :value | |
98 | ("gnutls-cli -p %p %h" | |
99 | "gnutls-cli -p %p %h --protocols ssl3" | |
100 | "openssl s_client -connect %h:%p -no_ssl2") | |
101 | (set :inline t | |
102 | ;; FIXME: add brief `:tag "..."' descriptions. | |
103 | ;; (repeat :inline t :tag "Other" (string)) | |
104 | ;; See `tls-checktrust': | |
105 | (const "gnutls-cli --x509cafile /etc/ssl/certs/ca-certificates.crt -p %p %h") | |
106 | (const "gnutls-cli --x509cafile /etc/ssl/certs/ca-certificates.crt -p %p %h --protocols ssl3") | |
107 | (const "openssl s_client -connect %h:%p -CAfile /etc/ssl/certs/ca-certificates.crt -no_ssl2") | |
108 | ;; No trust check: | |
109 | (const "gnutls-cli -p %p %h") | |
110 | (const "gnutls-cli -p %p %h --protocols ssl3") | |
111 | (const "openssl s_client -connect %h:%p -no_ssl2")) | |
112 | (repeat :inline t :tag "Other" (string))) | |
113 | (const :tag "Default list of commands" | |
114 | ("gnutls-cli -p %p %h" | |
115 | "gnutls-cli -p %p %h --protocols ssl3" | |
116 | "openssl s_client -connect %h:%p -no_ssl2")) | |
117 | (list :tag "List of commands" | |
118 | (repeat :tag "Command" (string)))) | |
3031d8b0 | 119 | :version "22.1" |
01b2d1dd SJ |
120 | :group 'tls) |
121 | ||
122 | (defcustom tls-process-connection-type nil | |
b890d447 | 123 | "Value for `process-connection-type' to use when starting TLS process." |
bf247b6e | 124 | :version "22.1" |
01b2d1dd SJ |
125 | :type 'boolean |
126 | :group 'tls) | |
127 | ||
3031d8b0 | 128 | (defcustom tls-success "- Handshake was completed\\|SSL handshake has read " |
b890d447 | 129 | "Regular expression indicating completed TLS handshakes. |
3031d8b0 MB |
130 | The default is what GNUTLS's \"gnutls-cli\" or OpenSSL's |
131 | \"openssl s_client\" outputs." | |
bf247b6e | 132 | :version "22.1" |
01b2d1dd SJ |
133 | :type 'regexp |
134 | :group 'tls) | |
135 | ||
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136 | (defcustom tls-checktrust nil |
137 | "Indicate if certificates should be checked against trusted root certs. | |
138 | If this is `ask', the user can decide whether to accept an | |
139 | untrusted certificate. You may have to adapt `tls-program' in | |
140 | order to make this feature work properly, i.e., to ensure that | |
141 | the external program knows about the root certificates you | |
142 | consider trustworthy, e.g.: | |
143 | ||
144 | \(setq tls-program | |
145 | '(\"gnutls-cli --x509cafile /etc/ssl/certs/ca-certificates.crt -p %p %h\" | |
146 | \"gnutls-cli --x509cafile /etc/ssl/certs/ca-certificates.crt -p %p %h --protocols ssl3\" | |
147 | \"openssl s_client -connect %h:%p -CAfile /etc/ssl/certs/ca-certificates.crt -no_ssl2\"))" | |
148 | :type '(choice (const :tag "Always" t) | |
149 | (const :tag "Never" nil) | |
150 | (const :tag "Ask" ask)) | |
dd22fbf6 | 151 | :version "23.1" ;; No Gnus |
b890d447 MB |
152 | :group 'tls) |
153 | ||
154 | (defcustom tls-untrusted | |
155 | "- Peer's certificate is NOT trusted\\|Verify return code: \\([^0] \\|.[^ ]\\)" | |
156 | "Regular expression indicating failure of TLS certificate verification. | |
157 | The default is what GNUTLS's \"gnutls-cli\" or OpenSSL's | |
158 | \"openssl s_client\" return in the event of unsuccessful | |
159 | verification." | |
160 | :type 'regexp | |
dd22fbf6 | 161 | :version "23.1" ;; No Gnus |
b890d447 MB |
162 | :group 'tls) |
163 | ||
164 | (defcustom tls-hostmismatch | |
165 | "# The hostname in the certificate does NOT match" | |
166 | "Regular expression indicating a host name mismatch in certificate. | |
167 | When the host name specified in the certificate doesn't match the | |
168 | name of the host you are connecting to, gnutls-cli issues a | |
169 | warning to this effect. There is no such feature in openssl. Set | |
170 | this to nil if you want to ignore host name mismatches." | |
171 | :type 'regexp | |
dd22fbf6 | 172 | :version "23.1" ;; No Gnus |
b890d447 MB |
173 | :group 'tls) |
174 | ||
18965008 SJ |
175 | (defcustom tls-certtool-program (executable-find "certtool") |
176 | "Name of GnuTLS certtool. | |
177 | Used by `tls-certificate-information'." | |
bf247b6e | 178 | :version "22.1" |
9bdd0e16 | 179 | :type 'string |
18965008 SJ |
180 | :group 'tls) |
181 | ||
182 | (defun tls-certificate-information (der) | |
183 | "Parse X.509 certificate in DER format into an assoc list." | |
184 | (let ((certificate (concat "-----BEGIN CERTIFICATE-----\n" | |
185 | (base64-encode-string der) | |
186 | "\n-----END CERTIFICATE-----\n")) | |
187 | (exit-code 0)) | |
188 | (with-current-buffer (get-buffer-create " *certtool*") | |
189 | (erase-buffer) | |
190 | (insert certificate) | |
191 | (setq exit-code (condition-case () | |
192 | (call-process-region (point-min) (point-max) | |
193 | tls-certtool-program | |
194 | t (list (current-buffer) nil) t | |
195 | "--certificate-info") | |
196 | (error -1))) | |
197 | (if (/= exit-code 0) | |
198 | nil | |
199 | (let ((vals nil)) | |
200 | (goto-char (point-min)) | |
201 | (while (re-search-forward "^\\([^:]+\\): \\(.*\\)" nil t) | |
202 | (push (cons (match-string 1) (match-string 2)) vals)) | |
203 | (nreverse vals)))))) | |
204 | ||
3031d8b0 MB |
205 | (defun open-tls-stream (name buffer host port) |
206 | "Open a TLS connection for a port to a host. | |
01b2d1dd SJ |
207 | Returns a subprocess-object to represent the connection. |
208 | Input and output work as for subprocesses; `delete-process' closes it. | |
3031d8b0 | 209 | Args are NAME BUFFER HOST PORT. |
01b2d1dd | 210 | NAME is name for process. It is modified if necessary to make it unique. |
b890d447 | 211 | BUFFER is the buffer (or buffer name) to associate with the process. |
01b2d1dd SJ |
212 | Process output goes at end of that buffer, unless you specify |
213 | an output stream or filter function to handle the output. | |
214 | BUFFER may be also nil, meaning that this process is not associated | |
215 | with any buffer | |
216 | Third arg is name of the host to connect to, or its IP address. | |
3031d8b0 | 217 | Fourth arg PORT is an integer specifying a port to connect to." |
0ad32c54 CY |
218 | (let ((cmds tls-program) |
219 | (use-temp-buffer (null buffer)) | |
220 | process cmd done) | |
221 | (if use-temp-buffer | |
222 | (setq buffer (generate-new-buffer " TLS"))) | |
cd6db47c | 223 | (with-current-buffer buffer |
59c95dc2 GM |
224 | (message "Opening TLS connection to `%s'..." host) |
225 | (while (and (not done) (setq cmd (pop cmds))) | |
226 | (message "Opening TLS connection with `%s'..." cmd) | |
227 | (let ((process-connection-type tls-process-connection-type) | |
228 | response) | |
229 | (setq process (start-process | |
230 | name buffer shell-file-name shell-command-switch | |
231 | (format-spec | |
232 | cmd | |
233 | (format-spec-make | |
234 | ?h host | |
235 | ?p (if (integerp port) | |
236 | (int-to-string port) | |
237 | port))))) | |
238 | (while (and process | |
239 | (memq (process-status process) '(open run)) | |
240 | (progn | |
241 | (goto-char (point-min)) | |
0a4d4654 GM |
242 | (not (setq done (re-search-forward |
243 | tls-success nil t))))) | |
59c95dc2 GM |
244 | (unless (accept-process-output process 1) |
245 | (sit-for 1))) | |
246 | (message "Opening TLS connection with `%s'...%s" cmd | |
247 | (if done "done" "failed")) | |
0a4d4654 GM |
248 | (if (not done) |
249 | (delete-process process) | |
250 | ;; advance point to after all informational messages that | |
251 | ;; `openssl s_client' and `gnutls' print | |
252 | (let ((start-of-data nil)) | |
253 | (while | |
ea666a77 RS |
254 | (not (setq start-of-data |
255 | ;; the string matching `tls-end-of-info' | |
256 | ;; might come in separate chunks from | |
257 | ;; `accept-process-output', so start the | |
258 | ;; search where `tls-success' ended | |
259 | (save-excursion | |
260 | (if (re-search-forward tls-end-of-info nil t) | |
261 | (match-end 0))))) | |
0a4d4654 GM |
262 | (accept-process-output process 1)) |
263 | (if start-of-data | |
264 | ;; move point to start of client data | |
265 | (goto-char start-of-data))) | |
ea666a77 | 266 | (setq done process)))) |
0a4d4654 GM |
267 | (when (and done |
268 | (or | |
269 | (and tls-checktrust | |
270 | (save-excursion | |
271 | (goto-char (point-min)) | |
272 | (re-search-forward tls-untrusted nil t)) | |
273 | (or | |
274 | (and (not (eq tls-checktrust 'ask)) | |
275 | (message "The certificate presented by `%s' is \ | |
276 | NOT trusted." host)) | |
277 | (not (yes-or-no-p | |
278 | (format "The certificate presented by `%s' is \ | |
279 | NOT trusted. Accept anyway? " host))))) | |
280 | (and tls-hostmismatch | |
281 | (save-excursion | |
282 | (goto-char (point-min)) | |
283 | (re-search-forward tls-hostmismatch nil t)) | |
284 | (not (yes-or-no-p | |
285 | (format "Host name in certificate doesn't \ | |
286 | match `%s'. Connect anyway? " host)))))) | |
287 | (setq done nil) | |
288 | (delete-process process))) | |
289 | (message "Opening TLS connection to `%s'...%s" | |
290 | host (if done "done" "failed")) | |
0ad32c54 | 291 | (when use-temp-buffer |
b7131d2f | 292 | (if done (set-process-buffer process nil)) |
0ad32c54 | 293 | (kill-buffer buffer)) |
01b2d1dd SJ |
294 | done)) |
295 | ||
296 | (provide 'tls) | |
297 | ||
cbee283d | 298 | ;; arch-tag: 5596d1c4-facc-4bc4-94a9-9863b928d7ac |
01b2d1dd | 299 | ;;; tls.el ends here |