blob: d816578c6243076d75d5e6829b5a84371ea98ee2 [file] [log] [blame]
Damien Miller733124b2007-10-26 14:25:12 +10001/* $OpenBSD: auth2-chall.c,v 1.33 2007/09/21 08:15:29 djm Exp $ */
Ben Lindstromdb65e8f2001-01-19 04:26:52 +00002/*
Ben Lindstrom92a2e382001-03-05 06:59:27 +00003 * Copyright (c) 2001 Markus Friedl. All rights reserved.
Ben Lindstrom551ea372001-06-05 18:56:16 +00004 * Copyright (c) 2001 Per Allansson. All rights reserved.
Ben Lindstromdb65e8f2001-01-19 04:26:52 +00005 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
Damien Millerd7834352006-08-05 12:39:39 +100026
Ben Lindstromdb65e8f2001-01-19 04:26:52 +000027#include "includes.h"
Ben Lindstromdb65e8f2001-01-19 04:26:52 +000028
Damien Millerd7834352006-08-05 12:39:39 +100029#include <sys/types.h>
30
Damien Millerded319c2006-09-01 15:38:36 +100031#include <stdarg.h>
Damien Millera7a73ee2006-08-05 11:37:59 +100032#include <stdio.h>
Damien Millere3476ed2006-07-24 14:13:33 +100033#include <string.h>
34
Damien Millerd7834352006-08-05 12:39:39 +100035#include "xmalloc.h"
Ben Lindstromdb65e8f2001-01-19 04:26:52 +000036#include "ssh2.h"
Damien Millerd7834352006-08-05 12:39:39 +100037#include "key.h"
38#include "hostfile.h"
Ben Lindstromdb65e8f2001-01-19 04:26:52 +000039#include "auth.h"
Damien Miller0e3b8722002-01-22 23:26:38 +110040#include "buffer.h"
Ben Lindstromdb65e8f2001-01-19 04:26:52 +000041#include "packet.h"
Ben Lindstromdb65e8f2001-01-19 04:26:52 +000042#include "dispatch.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000043#include "log.h"
Darren Tucker3c660802005-01-20 22:20:50 +110044#include "servconf.h"
45
46/* import */
47extern ServerOptions options;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +000048
Ben Lindstrombba81212001-06-25 05:01:22 +000049static int auth2_challenge_start(Authctxt *);
50static int send_userauth_info_request(Authctxt *);
Damien Miller630d6f42002-01-22 23:17:30 +110051static void input_userauth_info_response(int, u_int32_t, void *);
Ben Lindstrom551ea372001-06-05 18:56:16 +000052
53#ifdef BSD_AUTH
54extern KbdintDevice bsdauth_device;
55#else
Damien Miller4f9f42a2003-05-10 19:28:02 +100056#ifdef USE_PAM
57extern KbdintDevice sshpam_device;
58#endif
Ben Lindstrom551ea372001-06-05 18:56:16 +000059#ifdef SKEY
60extern KbdintDevice skey_device;
61#endif
62#endif
63
64KbdintDevice *devices[] = {
65#ifdef BSD_AUTH
66 &bsdauth_device,
67#else
Damien Miller4f9f42a2003-05-10 19:28:02 +100068#ifdef USE_PAM
69 &sshpam_device,
70#endif
Ben Lindstrom551ea372001-06-05 18:56:16 +000071#ifdef SKEY
72 &skey_device,
73#endif
74#endif
75 NULL
76};
77
78typedef struct KbdintAuthctxt KbdintAuthctxt;
79struct KbdintAuthctxt
80{
81 char *devices;
82 void *ctxt;
83 KbdintDevice *device;
Damien Millerfb7fd952002-06-26 23:58:39 +100084 u_int nreq;
Ben Lindstrom551ea372001-06-05 18:56:16 +000085};
86
Darren Tucker3c660802005-01-20 22:20:50 +110087#ifdef USE_PAM
88void
89remove_kbdint_device(const char *devname)
90{
91 int i, j;
92
93 for (i = 0; devices[i] != NULL; i++)
94 if (strcmp(devices[i]->name, devname) == 0) {
95 for (j = i; devices[j] != NULL; j++)
96 devices[j] = devices[j+1];
97 i--;
98 }
99}
100#endif
101
Ben Lindstrombba81212001-06-25 05:01:22 +0000102static KbdintAuthctxt *
Ben Lindstrom551ea372001-06-05 18:56:16 +0000103kbdint_alloc(const char *devs)
104{
105 KbdintAuthctxt *kbdintctxt;
Damien Miller0e3b8722002-01-22 23:26:38 +1100106 Buffer b;
Ben Lindstrom551ea372001-06-05 18:56:16 +0000107 int i;
Ben Lindstrom551ea372001-06-05 18:56:16 +0000108
Darren Tucker3c660802005-01-20 22:20:50 +1100109#ifdef USE_PAM
110 if (!options.use_pam)
111 remove_kbdint_device("pam");
112#endif
113
Ben Lindstrom551ea372001-06-05 18:56:16 +0000114 kbdintctxt = xmalloc(sizeof(KbdintAuthctxt));
115 if (strcmp(devs, "") == 0) {
Damien Miller0e3b8722002-01-22 23:26:38 +1100116 buffer_init(&b);
Ben Lindstrom551ea372001-06-05 18:56:16 +0000117 for (i = 0; devices[i]; i++) {
Damien Miller0e3b8722002-01-22 23:26:38 +1100118 if (buffer_len(&b) > 0)
119 buffer_append(&b, ",", 1);
120 buffer_append(&b, devices[i]->name,
121 strlen(devices[i]->name));
Ben Lindstrom551ea372001-06-05 18:56:16 +0000122 }
Damien Miller0e3b8722002-01-22 23:26:38 +1100123 buffer_append(&b, "\0", 1);
124 kbdintctxt->devices = xstrdup(buffer_ptr(&b));
125 buffer_free(&b);
Ben Lindstrom551ea372001-06-05 18:56:16 +0000126 } else {
127 kbdintctxt->devices = xstrdup(devs);
128 }
Damien Miller0e3b8722002-01-22 23:26:38 +1100129 debug("kbdint_alloc: devices '%s'", kbdintctxt->devices);
Ben Lindstrom551ea372001-06-05 18:56:16 +0000130 kbdintctxt->ctxt = NULL;
131 kbdintctxt->device = NULL;
Damien Millerfb7fd952002-06-26 23:58:39 +1000132 kbdintctxt->nreq = 0;
Ben Lindstrom551ea372001-06-05 18:56:16 +0000133
134 return kbdintctxt;
135}
Ben Lindstrombba81212001-06-25 05:01:22 +0000136static void
Ben Lindstrom551ea372001-06-05 18:56:16 +0000137kbdint_reset_device(KbdintAuthctxt *kbdintctxt)
138{
139 if (kbdintctxt->ctxt) {
140 kbdintctxt->device->free_ctx(kbdintctxt->ctxt);
141 kbdintctxt->ctxt = NULL;
142 }
143 kbdintctxt->device = NULL;
144}
Ben Lindstrombba81212001-06-25 05:01:22 +0000145static void
Ben Lindstrom551ea372001-06-05 18:56:16 +0000146kbdint_free(KbdintAuthctxt *kbdintctxt)
147{
148 if (kbdintctxt->device)
149 kbdint_reset_device(kbdintctxt);
150 if (kbdintctxt->devices) {
151 xfree(kbdintctxt->devices);
152 kbdintctxt->devices = NULL;
153 }
154 xfree(kbdintctxt);
155}
156/* get next device */
Ben Lindstrombba81212001-06-25 05:01:22 +0000157static int
Ben Lindstrom551ea372001-06-05 18:56:16 +0000158kbdint_next_device(KbdintAuthctxt *kbdintctxt)
159{
160 size_t len;
161 char *t;
162 int i;
163
164 if (kbdintctxt->device)
165 kbdint_reset_device(kbdintctxt);
166 do {
167 len = kbdintctxt->devices ?
168 strcspn(kbdintctxt->devices, ",") : 0;
169
170 if (len == 0)
171 break;
172 for (i = 0; devices[i]; i++)
173 if (strncmp(kbdintctxt->devices, devices[i]->name, len) == 0)
174 kbdintctxt->device = devices[i];
175 t = kbdintctxt->devices;
176 kbdintctxt->devices = t[len] ? xstrdup(t+len+1) : NULL;
177 xfree(t);
178 debug2("kbdint_next_device: devices %s", kbdintctxt->devices ?
Damien Miller0dc1bef2005-07-17 17:22:45 +1000179 kbdintctxt->devices : "<empty>");
Ben Lindstrom551ea372001-06-05 18:56:16 +0000180 } while (kbdintctxt->devices && !kbdintctxt->device);
181
182 return kbdintctxt->device ? 1 : 0;
183}
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000184
185/*
Ben Lindstrombdfb4df2001-10-03 17:12:43 +0000186 * try challenge-response, set authctxt->postponed if we have to
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000187 * wait for the response.
188 */
189int
190auth2_challenge(Authctxt *authctxt, char *devs)
191{
Ben Lindstrom551ea372001-06-05 18:56:16 +0000192 debug("auth2_challenge: user=%s devs=%s",
193 authctxt->user ? authctxt->user : "<nouser>",
194 devs ? devs : "<no devs>");
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000195
Ben Lindstrom742e89e2001-06-09 01:17:23 +0000196 if (authctxt->user == NULL || !devs)
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000197 return 0;
Damien Miller9f0f5c62001-12-21 14:45:46 +1100198 if (authctxt->kbdintctxt == NULL)
Ben Lindstrom551ea372001-06-05 18:56:16 +0000199 authctxt->kbdintctxt = kbdint_alloc(devs);
200 return auth2_challenge_start(authctxt);
201}
202
Damien Milleree116252001-12-21 12:42:34 +1100203/* unregister kbd-int callbacks and context */
204void
205auth2_challenge_stop(Authctxt *authctxt)
206{
207 /* unregister callback */
208 dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, NULL);
Damien Miller80163902007-01-05 16:30:16 +1100209 if (authctxt->kbdintctxt != NULL) {
Damien Milleree116252001-12-21 12:42:34 +1100210 kbdint_free(authctxt->kbdintctxt);
211 authctxt->kbdintctxt = NULL;
212 }
213}
214
Ben Lindstrom551ea372001-06-05 18:56:16 +0000215/* side effect: sets authctxt->postponed if a reply was sent*/
216static int
217auth2_challenge_start(Authctxt *authctxt)
218{
219 KbdintAuthctxt *kbdintctxt = authctxt->kbdintctxt;
220
221 debug2("auth2_challenge_start: devices %s",
222 kbdintctxt->devices ? kbdintctxt->devices : "<empty>");
223
224 if (kbdint_next_device(kbdintctxt) == 0) {
Damien Milleree116252001-12-21 12:42:34 +1100225 auth2_challenge_stop(authctxt);
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000226 return 0;
Ben Lindstrom551ea372001-06-05 18:56:16 +0000227 }
228 debug("auth2_challenge_start: trying authentication method '%s'",
229 kbdintctxt->device->name);
230
231 if ((kbdintctxt->ctxt = kbdintctxt->device->init_ctx(authctxt)) == NULL) {
Damien Milleree116252001-12-21 12:42:34 +1100232 auth2_challenge_stop(authctxt);
Ben Lindstrom551ea372001-06-05 18:56:16 +0000233 return 0;
234 }
235 if (send_userauth_info_request(authctxt) == 0) {
Damien Milleree116252001-12-21 12:42:34 +1100236 auth2_challenge_stop(authctxt);
Ben Lindstrom551ea372001-06-05 18:56:16 +0000237 return 0;
238 }
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000239 dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE,
240 &input_userauth_info_response);
Ben Lindstrom551ea372001-06-05 18:56:16 +0000241
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000242 authctxt->postponed = 1;
243 return 0;
244}
245
Ben Lindstrom551ea372001-06-05 18:56:16 +0000246static int
247send_userauth_info_request(Authctxt *authctxt)
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000248{
Ben Lindstrom551ea372001-06-05 18:56:16 +0000249 KbdintAuthctxt *kbdintctxt;
250 char *name, *instr, **prompts;
Damien Millereccb9de2005-06-17 12:59:34 +1000251 u_int i, *echo_on;
Ben Lindstrom551ea372001-06-05 18:56:16 +0000252
253 kbdintctxt = authctxt->kbdintctxt;
254 if (kbdintctxt->device->query(kbdintctxt->ctxt,
Damien Millerfb7fd952002-06-26 23:58:39 +1000255 &name, &instr, &kbdintctxt->nreq, &prompts, &echo_on))
Ben Lindstrom551ea372001-06-05 18:56:16 +0000256 return 0;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000257
258 packet_start(SSH2_MSG_USERAUTH_INFO_REQUEST);
Ben Lindstrom551ea372001-06-05 18:56:16 +0000259 packet_put_cstring(name);
260 packet_put_cstring(instr);
Ben Lindstromcb72e4f2002-06-21 00:41:51 +0000261 packet_put_cstring(""); /* language not used */
Damien Millerfb7fd952002-06-26 23:58:39 +1000262 packet_put_int(kbdintctxt->nreq);
263 for (i = 0; i < kbdintctxt->nreq; i++) {
Ben Lindstrom551ea372001-06-05 18:56:16 +0000264 packet_put_cstring(prompts[i]);
265 packet_put_char(echo_on[i]);
266 }
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000267 packet_send();
268 packet_write_wait();
Ben Lindstrom551ea372001-06-05 18:56:16 +0000269
Damien Millerfb7fd952002-06-26 23:58:39 +1000270 for (i = 0; i < kbdintctxt->nreq; i++)
Ben Lindstrom551ea372001-06-05 18:56:16 +0000271 xfree(prompts[i]);
272 xfree(prompts);
273 xfree(echo_on);
274 xfree(name);
275 xfree(instr);
276 return 1;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000277}
278
Ben Lindstrom551ea372001-06-05 18:56:16 +0000279static void
Damien Miller630d6f42002-01-22 23:17:30 +1100280input_userauth_info_response(int type, u_int32_t seq, void *ctxt)
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000281{
282 Authctxt *authctxt = ctxt;
Ben Lindstrom551ea372001-06-05 18:56:16 +0000283 KbdintAuthctxt *kbdintctxt;
Damien Millereccb9de2005-06-17 12:59:34 +1000284 int authenticated = 0, res, len;
285 u_int i, nresp;
Ben Lindstrom551ea372001-06-05 18:56:16 +0000286 char **response = NULL, *method;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000287
288 if (authctxt == NULL)
289 fatal("input_userauth_info_response: no authctxt");
Ben Lindstrom551ea372001-06-05 18:56:16 +0000290 kbdintctxt = authctxt->kbdintctxt;
291 if (kbdintctxt == NULL || kbdintctxt->ctxt == NULL)
292 fatal("input_userauth_info_response: no kbdintctxt");
293 if (kbdintctxt->device == NULL)
294 fatal("input_userauth_info_response: no device");
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000295
296 authctxt->postponed = 0; /* reset */
297 nresp = packet_get_int();
Damien Millerfb7fd952002-06-26 23:58:39 +1000298 if (nresp != kbdintctxt->nreq)
299 fatal("input_userauth_info_response: wrong number of replies");
300 if (nresp > 100)
301 fatal("input_userauth_info_response: too many replies");
Ben Lindstrom551ea372001-06-05 18:56:16 +0000302 if (nresp > 0) {
Damien Miller07d86be2006-03-26 14:19:21 +1100303 response = xcalloc(nresp, sizeof(char *));
Ben Lindstrom551ea372001-06-05 18:56:16 +0000304 for (i = 0; i < nresp; i++)
305 response[i] = packet_get_string(NULL);
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000306 }
Damien Miller48b03fc2002-01-22 23:11:40 +1100307 packet_check_eom();
Ben Lindstrom551ea372001-06-05 18:56:16 +0000308
Darren Tucker611649e2005-01-20 11:05:34 +1100309 res = kbdintctxt->device->respond(kbdintctxt->ctxt, nresp, response);
Ben Lindstrom551ea372001-06-05 18:56:16 +0000310
311 for (i = 0; i < nresp; i++) {
312 memset(response[i], 'r', strlen(response[i]));
313 xfree(response[i]);
314 }
315 if (response)
316 xfree(response);
317
318 switch (res) {
319 case 0:
320 /* Success! */
Darren Tucker611649e2005-01-20 11:05:34 +1100321 authenticated = authctxt->valid ? 1 : 0;
Ben Lindstrom551ea372001-06-05 18:56:16 +0000322 break;
323 case 1:
324 /* Authentication needs further interaction */
Damien Milleree116252001-12-21 12:42:34 +1100325 if (send_userauth_info_request(authctxt) == 1)
326 authctxt->postponed = 1;
Ben Lindstrom551ea372001-06-05 18:56:16 +0000327 break;
328 default:
329 /* Failure! */
330 break;
331 }
332
333 len = strlen("keyboard-interactive") + 2 +
334 strlen(kbdintctxt->device->name);
335 method = xmalloc(len);
Damien Miller209ee4e2002-01-22 23:25:08 +1100336 snprintf(method, len, "keyboard-interactive/%s",
337 kbdintctxt->device->name);
Ben Lindstrom551ea372001-06-05 18:56:16 +0000338
339 if (!authctxt->postponed) {
Ben Lindstrom551ea372001-06-05 18:56:16 +0000340 if (authenticated) {
Damien Milleree116252001-12-21 12:42:34 +1100341 auth2_challenge_stop(authctxt);
Ben Lindstrom551ea372001-06-05 18:56:16 +0000342 } else {
343 /* start next device */
344 /* may set authctxt->postponed */
345 auth2_challenge_start(authctxt);
346 }
347 }
Damien Miller5d57e502001-03-30 10:48:31 +1000348 userauth_finish(authctxt, authenticated, method);
Ben Lindstrom551ea372001-06-05 18:56:16 +0000349 xfree(method);
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000350}
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000351
352void
353privsep_challenge_enable(void)
354{
Damien Millera6a7c192003-05-26 21:36:13 +1000355#if defined(BSD_AUTH) || defined(USE_PAM) || defined(SKEY)
356 int n = 0;
357#endif
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000358#ifdef BSD_AUTH
359 extern KbdintDevice mm_bsdauth_device;
360#endif
Damien Miller4f9f42a2003-05-10 19:28:02 +1000361#ifdef USE_PAM
362 extern KbdintDevice mm_sshpam_device;
363#endif
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000364#ifdef SKEY
365 extern KbdintDevice mm_skey_device;
366#endif
Damien Miller4f9f42a2003-05-10 19:28:02 +1000367
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000368#ifdef BSD_AUTH
Damien Miller4f9f42a2003-05-10 19:28:02 +1000369 devices[n++] = &mm_bsdauth_device;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000370#else
Damien Miller4f9f42a2003-05-10 19:28:02 +1000371#ifdef USE_PAM
372 devices[n++] = &mm_sshpam_device;
373#endif
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000374#ifdef SKEY
Damien Miller4f9f42a2003-05-10 19:28:02 +1000375 devices[n++] = &mm_skey_device;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000376#endif
377#endif
378}