blob: 98f3093ce2fde6e91ef01240906222a6b1e987f4 [file] [log] [blame]
Darren Tuckera627d422013-06-02 07:31:17 +10001/* $OpenBSD: auth2-chall.c,v 1.38 2013/05/17 00:13:13 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);
Darren Tuckera627d422013-06-02 07:31:17 +1000150 free(kbdintctxt->devices);
151 bzero(kbdintctxt, sizeof(*kbdintctxt));
152 free(kbdintctxt);
Ben Lindstrom551ea372001-06-05 18:56:16 +0000153}
154/* get next device */
Ben Lindstrombba81212001-06-25 05:01:22 +0000155static int
Damien Miller91a55f22013-04-23 15:18:10 +1000156kbdint_next_device(Authctxt *authctxt, KbdintAuthctxt *kbdintctxt)
Ben Lindstrom551ea372001-06-05 18:56:16 +0000157{
158 size_t len;
159 char *t;
160 int i;
161
162 if (kbdintctxt->device)
163 kbdint_reset_device(kbdintctxt);
164 do {
165 len = kbdintctxt->devices ?
166 strcspn(kbdintctxt->devices, ",") : 0;
167
168 if (len == 0)
169 break;
Damien Miller91a55f22013-04-23 15:18:10 +1000170 for (i = 0; devices[i]; i++) {
171 if (!auth2_method_allowed(authctxt,
172 "keyboard-interactive", devices[i]->name))
173 continue;
Ben Lindstrom551ea372001-06-05 18:56:16 +0000174 if (strncmp(kbdintctxt->devices, devices[i]->name, len) == 0)
175 kbdintctxt->device = devices[i];
Damien Miller91a55f22013-04-23 15:18:10 +1000176 }
Ben Lindstrom551ea372001-06-05 18:56:16 +0000177 t = kbdintctxt->devices;
178 kbdintctxt->devices = t[len] ? xstrdup(t+len+1) : NULL;
Darren Tuckera627d422013-06-02 07:31:17 +1000179 free(t);
Ben Lindstrom551ea372001-06-05 18:56:16 +0000180 debug2("kbdint_next_device: devices %s", kbdintctxt->devices ?
Damien Miller0dc1bef2005-07-17 17:22:45 +1000181 kbdintctxt->devices : "<empty>");
Ben Lindstrom551ea372001-06-05 18:56:16 +0000182 } while (kbdintctxt->devices && !kbdintctxt->device);
183
184 return kbdintctxt->device ? 1 : 0;
185}
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000186
187/*
Ben Lindstrombdfb4df2001-10-03 17:12:43 +0000188 * try challenge-response, set authctxt->postponed if we have to
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000189 * wait for the response.
190 */
191int
192auth2_challenge(Authctxt *authctxt, char *devs)
193{
Ben Lindstrom551ea372001-06-05 18:56:16 +0000194 debug("auth2_challenge: user=%s devs=%s",
195 authctxt->user ? authctxt->user : "<nouser>",
196 devs ? devs : "<no devs>");
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000197
Ben Lindstrom742e89e2001-06-09 01:17:23 +0000198 if (authctxt->user == NULL || !devs)
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000199 return 0;
Damien Miller9f0f5c62001-12-21 14:45:46 +1100200 if (authctxt->kbdintctxt == NULL)
Ben Lindstrom551ea372001-06-05 18:56:16 +0000201 authctxt->kbdintctxt = kbdint_alloc(devs);
202 return auth2_challenge_start(authctxt);
203}
204
Damien Milleree116252001-12-21 12:42:34 +1100205/* unregister kbd-int callbacks and context */
206void
207auth2_challenge_stop(Authctxt *authctxt)
208{
209 /* unregister callback */
210 dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, NULL);
Damien Miller80163902007-01-05 16:30:16 +1100211 if (authctxt->kbdintctxt != NULL) {
Damien Milleree116252001-12-21 12:42:34 +1100212 kbdint_free(authctxt->kbdintctxt);
213 authctxt->kbdintctxt = NULL;
214 }
215}
216
Ben Lindstrom551ea372001-06-05 18:56:16 +0000217/* side effect: sets authctxt->postponed if a reply was sent*/
218static int
219auth2_challenge_start(Authctxt *authctxt)
220{
221 KbdintAuthctxt *kbdintctxt = authctxt->kbdintctxt;
222
223 debug2("auth2_challenge_start: devices %s",
224 kbdintctxt->devices ? kbdintctxt->devices : "<empty>");
225
Damien Miller91a55f22013-04-23 15:18:10 +1000226 if (kbdint_next_device(authctxt, kbdintctxt) == 0) {
Damien Milleree116252001-12-21 12:42:34 +1100227 auth2_challenge_stop(authctxt);
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000228 return 0;
Ben Lindstrom551ea372001-06-05 18:56:16 +0000229 }
230 debug("auth2_challenge_start: trying authentication method '%s'",
231 kbdintctxt->device->name);
232
233 if ((kbdintctxt->ctxt = kbdintctxt->device->init_ctx(authctxt)) == NULL) {
Damien Milleree116252001-12-21 12:42:34 +1100234 auth2_challenge_stop(authctxt);
Ben Lindstrom551ea372001-06-05 18:56:16 +0000235 return 0;
236 }
237 if (send_userauth_info_request(authctxt) == 0) {
Damien Milleree116252001-12-21 12:42:34 +1100238 auth2_challenge_stop(authctxt);
Ben Lindstrom551ea372001-06-05 18:56:16 +0000239 return 0;
240 }
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000241 dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE,
242 &input_userauth_info_response);
Ben Lindstrom551ea372001-06-05 18:56:16 +0000243
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000244 authctxt->postponed = 1;
245 return 0;
246}
247
Ben Lindstrom551ea372001-06-05 18:56:16 +0000248static int
249send_userauth_info_request(Authctxt *authctxt)
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000250{
Ben Lindstrom551ea372001-06-05 18:56:16 +0000251 KbdintAuthctxt *kbdintctxt;
252 char *name, *instr, **prompts;
Damien Millereccb9de2005-06-17 12:59:34 +1000253 u_int i, *echo_on;
Ben Lindstrom551ea372001-06-05 18:56:16 +0000254
255 kbdintctxt = authctxt->kbdintctxt;
256 if (kbdintctxt->device->query(kbdintctxt->ctxt,
Damien Millerfb7fd952002-06-26 23:58:39 +1000257 &name, &instr, &kbdintctxt->nreq, &prompts, &echo_on))
Ben Lindstrom551ea372001-06-05 18:56:16 +0000258 return 0;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000259
260 packet_start(SSH2_MSG_USERAUTH_INFO_REQUEST);
Ben Lindstrom551ea372001-06-05 18:56:16 +0000261 packet_put_cstring(name);
262 packet_put_cstring(instr);
Ben Lindstromcb72e4f2002-06-21 00:41:51 +0000263 packet_put_cstring(""); /* language not used */
Damien Millerfb7fd952002-06-26 23:58:39 +1000264 packet_put_int(kbdintctxt->nreq);
265 for (i = 0; i < kbdintctxt->nreq; i++) {
Ben Lindstrom551ea372001-06-05 18:56:16 +0000266 packet_put_cstring(prompts[i]);
267 packet_put_char(echo_on[i]);
268 }
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000269 packet_send();
270 packet_write_wait();
Ben Lindstrom551ea372001-06-05 18:56:16 +0000271
Damien Millerfb7fd952002-06-26 23:58:39 +1000272 for (i = 0; i < kbdintctxt->nreq; i++)
Darren Tuckera627d422013-06-02 07:31:17 +1000273 free(prompts[i]);
274 free(prompts);
275 free(echo_on);
276 free(name);
277 free(instr);
Ben Lindstrom551ea372001-06-05 18:56:16 +0000278 return 1;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000279}
280
Ben Lindstrom551ea372001-06-05 18:56:16 +0000281static void
Damien Miller630d6f42002-01-22 23:17:30 +1100282input_userauth_info_response(int type, u_int32_t seq, void *ctxt)
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000283{
284 Authctxt *authctxt = ctxt;
Ben Lindstrom551ea372001-06-05 18:56:16 +0000285 KbdintAuthctxt *kbdintctxt;
Damien Millerc30def92009-01-28 16:13:39 +1100286 int authenticated = 0, res;
Damien Millereccb9de2005-06-17 12:59:34 +1000287 u_int i, nresp;
Damien Miller55aca022012-12-03 11:25:30 +1100288 const char *devicename = NULL;
289 char **response = NULL;
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000290
291 if (authctxt == NULL)
292 fatal("input_userauth_info_response: no authctxt");
Ben Lindstrom551ea372001-06-05 18:56:16 +0000293 kbdintctxt = authctxt->kbdintctxt;
294 if (kbdintctxt == NULL || kbdintctxt->ctxt == NULL)
295 fatal("input_userauth_info_response: no kbdintctxt");
296 if (kbdintctxt->device == NULL)
297 fatal("input_userauth_info_response: no device");
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000298
299 authctxt->postponed = 0; /* reset */
300 nresp = packet_get_int();
Damien Millerfb7fd952002-06-26 23:58:39 +1000301 if (nresp != kbdintctxt->nreq)
302 fatal("input_userauth_info_response: wrong number of replies");
303 if (nresp > 100)
304 fatal("input_userauth_info_response: too many replies");
Ben Lindstrom551ea372001-06-05 18:56:16 +0000305 if (nresp > 0) {
Damien Miller07d86be2006-03-26 14:19:21 +1100306 response = xcalloc(nresp, sizeof(char *));
Ben Lindstrom551ea372001-06-05 18:56:16 +0000307 for (i = 0; i < nresp; i++)
308 response[i] = packet_get_string(NULL);
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000309 }
Damien Miller48b03fc2002-01-22 23:11:40 +1100310 packet_check_eom();
Ben Lindstrom551ea372001-06-05 18:56:16 +0000311
Darren Tucker611649e2005-01-20 11:05:34 +1100312 res = kbdintctxt->device->respond(kbdintctxt->ctxt, nresp, response);
Ben Lindstrom551ea372001-06-05 18:56:16 +0000313
314 for (i = 0; i < nresp; i++) {
315 memset(response[i], 'r', strlen(response[i]));
Darren Tuckera627d422013-06-02 07:31:17 +1000316 free(response[i]);
Ben Lindstrom551ea372001-06-05 18:56:16 +0000317 }
Darren Tuckera627d422013-06-02 07:31:17 +1000318 free(response);
Ben Lindstrom551ea372001-06-05 18:56:16 +0000319
320 switch (res) {
321 case 0:
322 /* Success! */
Darren Tucker611649e2005-01-20 11:05:34 +1100323 authenticated = authctxt->valid ? 1 : 0;
Ben Lindstrom551ea372001-06-05 18:56:16 +0000324 break;
325 case 1:
326 /* Authentication needs further interaction */
Damien Milleree116252001-12-21 12:42:34 +1100327 if (send_userauth_info_request(authctxt) == 1)
328 authctxt->postponed = 1;
Ben Lindstrom551ea372001-06-05 18:56:16 +0000329 break;
330 default:
331 /* Failure! */
332 break;
333 }
Damien Miller15b05cf2012-12-03 09:53:20 +1100334 devicename = kbdintctxt->device->name;
Ben Lindstrom551ea372001-06-05 18:56:16 +0000335 if (!authctxt->postponed) {
Ben Lindstrom551ea372001-06-05 18:56:16 +0000336 if (authenticated) {
Damien Milleree116252001-12-21 12:42:34 +1100337 auth2_challenge_stop(authctxt);
Ben Lindstrom551ea372001-06-05 18:56:16 +0000338 } else {
339 /* start next device */
340 /* may set authctxt->postponed */
341 auth2_challenge_start(authctxt);
342 }
343 }
Damien Miller15b05cf2012-12-03 09:53:20 +1100344 userauth_finish(authctxt, authenticated, "keyboard-interactive",
345 devicename);
Ben Lindstromdb65e8f2001-01-19 04:26:52 +0000346}
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000347
348void
349privsep_challenge_enable(void)
350{
Damien Millera6a7c192003-05-26 21:36:13 +1000351#if defined(BSD_AUTH) || defined(USE_PAM) || defined(SKEY)
352 int n = 0;
353#endif
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000354#ifdef BSD_AUTH
355 extern KbdintDevice mm_bsdauth_device;
356#endif
Damien Miller4f9f42a2003-05-10 19:28:02 +1000357#ifdef USE_PAM
358 extern KbdintDevice mm_sshpam_device;
359#endif
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000360#ifdef SKEY
361 extern KbdintDevice mm_skey_device;
362#endif
Damien Miller4f9f42a2003-05-10 19:28:02 +1000363
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000364#ifdef BSD_AUTH
Damien Miller4f9f42a2003-05-10 19:28:02 +1000365 devices[n++] = &mm_bsdauth_device;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000366#else
Damien Miller4f9f42a2003-05-10 19:28:02 +1000367#ifdef USE_PAM
368 devices[n++] = &mm_sshpam_device;
369#endif
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000370#ifdef SKEY
Damien Miller4f9f42a2003-05-10 19:28:02 +1000371 devices[n++] = &mm_skey_device;
Ben Lindstrom7a2073c2002-03-22 02:30:41 +0000372#endif
373#endif
374}