]> andersk Git - openssh.git/blame - auth2-chall.c
- markus@cvs.openbsd.org 2005/06/16 08:00:00
[openssh.git] / auth2-chall.c
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59c97189 1/*
f3c7c613 2 * Copyright (c) 2001 Markus Friedl. All rights reserved.
5ba55ada 3 * Copyright (c) 2001 Per Allansson. All rights reserved.
59c97189 4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25#include "includes.h"
37ea4f91 26RCSID("$OpenBSD: auth2-chall.c,v 1.22 2005/01/19 13:11:47 dtucker Exp $");
59c97189 27
59c97189 28#include "ssh2.h"
29#include "auth.h"
3469eac4 30#include "buffer.h"
59c97189 31#include "packet.h"
32#include "xmalloc.h"
33#include "dispatch.h"
42f11eb2 34#include "log.h"
c384a74c 35#include "servconf.h"
36
37/* import */
38extern ServerOptions options;
59c97189 39
396c147e 40static int auth2_challenge_start(Authctxt *);
41static int send_userauth_info_request(Authctxt *);
7819b5c3 42static void input_userauth_info_response(int, u_int32_t, void *);
5ba55ada 43
44#ifdef BSD_AUTH
45extern KbdintDevice bsdauth_device;
46#else
05114c74 47#ifdef USE_PAM
48extern KbdintDevice sshpam_device;
49#endif
5ba55ada 50#ifdef SKEY
51extern KbdintDevice skey_device;
52#endif
53#endif
54
55KbdintDevice *devices[] = {
56#ifdef BSD_AUTH
57 &bsdauth_device,
58#else
05114c74 59#ifdef USE_PAM
60 &sshpam_device,
61#endif
5ba55ada 62#ifdef SKEY
63 &skey_device,
64#endif
65#endif
66 NULL
67};
68
69typedef struct KbdintAuthctxt KbdintAuthctxt;
70struct KbdintAuthctxt
71{
72 char *devices;
73 void *ctxt;
74 KbdintDevice *device;
477edc5d 75 u_int nreq;
5ba55ada 76};
77
c384a74c 78#ifdef USE_PAM
79void
80remove_kbdint_device(const char *devname)
81{
82 int i, j;
83
84 for (i = 0; devices[i] != NULL; i++)
85 if (strcmp(devices[i]->name, devname) == 0) {
86 for (j = i; devices[j] != NULL; j++)
87 devices[j] = devices[j+1];
88 i--;
89 }
90}
91#endif
92
396c147e 93static KbdintAuthctxt *
5ba55ada 94kbdint_alloc(const char *devs)
95{
96 KbdintAuthctxt *kbdintctxt;
3469eac4 97 Buffer b;
5ba55ada 98 int i;
5ba55ada 99
c384a74c 100#ifdef USE_PAM
101 if (!options.use_pam)
102 remove_kbdint_device("pam");
103#endif
104
5ba55ada 105 kbdintctxt = xmalloc(sizeof(KbdintAuthctxt));
106 if (strcmp(devs, "") == 0) {
3469eac4 107 buffer_init(&b);
5ba55ada 108 for (i = 0; devices[i]; i++) {
3469eac4 109 if (buffer_len(&b) > 0)
110 buffer_append(&b, ",", 1);
111 buffer_append(&b, devices[i]->name,
112 strlen(devices[i]->name));
5ba55ada 113 }
3469eac4 114 buffer_append(&b, "\0", 1);
115 kbdintctxt->devices = xstrdup(buffer_ptr(&b));
116 buffer_free(&b);
5ba55ada 117 } else {
118 kbdintctxt->devices = xstrdup(devs);
119 }
3469eac4 120 debug("kbdint_alloc: devices '%s'", kbdintctxt->devices);
5ba55ada 121 kbdintctxt->ctxt = NULL;
122 kbdintctxt->device = NULL;
477edc5d 123 kbdintctxt->nreq = 0;
5ba55ada 124
125 return kbdintctxt;
126}
396c147e 127static void
5ba55ada 128kbdint_reset_device(KbdintAuthctxt *kbdintctxt)
129{
130 if (kbdintctxt->ctxt) {
131 kbdintctxt->device->free_ctx(kbdintctxt->ctxt);
132 kbdintctxt->ctxt = NULL;
133 }
134 kbdintctxt->device = NULL;
135}
396c147e 136static void
5ba55ada 137kbdint_free(KbdintAuthctxt *kbdintctxt)
138{
139 if (kbdintctxt->device)
140 kbdint_reset_device(kbdintctxt);
141 if (kbdintctxt->devices) {
142 xfree(kbdintctxt->devices);
143 kbdintctxt->devices = NULL;
144 }
145 xfree(kbdintctxt);
146}
147/* get next device */
396c147e 148static int
5ba55ada 149kbdint_next_device(KbdintAuthctxt *kbdintctxt)
150{
151 size_t len;
152 char *t;
153 int i;
154
155 if (kbdintctxt->device)
156 kbdint_reset_device(kbdintctxt);
157 do {
158 len = kbdintctxt->devices ?
159 strcspn(kbdintctxt->devices, ",") : 0;
160
161 if (len == 0)
162 break;
163 for (i = 0; devices[i]; i++)
164 if (strncmp(kbdintctxt->devices, devices[i]->name, len) == 0)
165 kbdintctxt->device = devices[i];
166 t = kbdintctxt->devices;
167 kbdintctxt->devices = t[len] ? xstrdup(t+len+1) : NULL;
168 xfree(t);
169 debug2("kbdint_next_device: devices %s", kbdintctxt->devices ?
170 kbdintctxt->devices : "<empty>");
171 } while (kbdintctxt->devices && !kbdintctxt->device);
172
173 return kbdintctxt->device ? 1 : 0;
174}
59c97189 175
176/*
aa8003d6 177 * try challenge-response, set authctxt->postponed if we have to
59c97189 178 * wait for the response.
179 */
180int
181auth2_challenge(Authctxt *authctxt, char *devs)
182{
5ba55ada 183 debug("auth2_challenge: user=%s devs=%s",
184 authctxt->user ? authctxt->user : "<nouser>",
185 devs ? devs : "<no devs>");
186
f5e69c65 187 if (authctxt->user == NULL || !devs)
5ba55ada 188 return 0;
184eed6a 189 if (authctxt->kbdintctxt == NULL)
5ba55ada 190 authctxt->kbdintctxt = kbdint_alloc(devs);
191 return auth2_challenge_start(authctxt);
192}
193
2f293d43 194/* unregister kbd-int callbacks and context */
195void
196auth2_challenge_stop(Authctxt *authctxt)
197{
198 /* unregister callback */
199 dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, NULL);
200 if (authctxt->kbdintctxt != NULL) {
201 kbdint_free(authctxt->kbdintctxt);
202 authctxt->kbdintctxt = NULL;
203 }
204}
205
5ba55ada 206/* side effect: sets authctxt->postponed if a reply was sent*/
207static int
208auth2_challenge_start(Authctxt *authctxt)
209{
210 KbdintAuthctxt *kbdintctxt = authctxt->kbdintctxt;
211
212 debug2("auth2_challenge_start: devices %s",
213 kbdintctxt->devices ? kbdintctxt->devices : "<empty>");
214
215 if (kbdint_next_device(kbdintctxt) == 0) {
2f293d43 216 auth2_challenge_stop(authctxt);
5ba55ada 217 return 0;
218 }
219 debug("auth2_challenge_start: trying authentication method '%s'",
220 kbdintctxt->device->name);
59c97189 221
5ba55ada 222 if ((kbdintctxt->ctxt = kbdintctxt->device->init_ctx(authctxt)) == NULL) {
2f293d43 223 auth2_challenge_stop(authctxt);
59c97189 224 return 0;
5ba55ada 225 }
226 if (send_userauth_info_request(authctxt) == 0) {
2f293d43 227 auth2_challenge_stop(authctxt);
59c97189 228 return 0;
5ba55ada 229 }
59c97189 230 dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE,
231 &input_userauth_info_response);
5ba55ada 232
59c97189 233 authctxt->postponed = 1;
234 return 0;
235}
236
5ba55ada 237static int
238send_userauth_info_request(Authctxt *authctxt)
59c97189 239{
5ba55ada 240 KbdintAuthctxt *kbdintctxt;
241 char *name, *instr, **prompts;
242 int i;
477edc5d 243 u_int *echo_on;
5ba55ada 244
245 kbdintctxt = authctxt->kbdintctxt;
246 if (kbdintctxt->device->query(kbdintctxt->ctxt,
477edc5d 247 &name, &instr, &kbdintctxt->nreq, &prompts, &echo_on))
5ba55ada 248 return 0;
59c97189 249
250 packet_start(SSH2_MSG_USERAUTH_INFO_REQUEST);
5ba55ada 251 packet_put_cstring(name);
252 packet_put_cstring(instr);
7203d6bb 253 packet_put_cstring(""); /* language not used */
477edc5d 254 packet_put_int(kbdintctxt->nreq);
255 for (i = 0; i < kbdintctxt->nreq; i++) {
5ba55ada 256 packet_put_cstring(prompts[i]);
257 packet_put_char(echo_on[i]);
258 }
59c97189 259 packet_send();
260 packet_write_wait();
5ba55ada 261
477edc5d 262 for (i = 0; i < kbdintctxt->nreq; i++)
5ba55ada 263 xfree(prompts[i]);
264 xfree(prompts);
265 xfree(echo_on);
266 xfree(name);
267 xfree(instr);
268 return 1;
59c97189 269}
270
5ba55ada 271static void
7819b5c3 272input_userauth_info_response(int type, u_int32_t seq, void *ctxt)
59c97189 273{
274 Authctxt *authctxt = ctxt;
5ba55ada 275 KbdintAuthctxt *kbdintctxt;
276 int i, authenticated = 0, res, len;
277 u_int nresp;
278 char **response = NULL, *method;
59c97189 279
280 if (authctxt == NULL)
281 fatal("input_userauth_info_response: no authctxt");
5ba55ada 282 kbdintctxt = authctxt->kbdintctxt;
283 if (kbdintctxt == NULL || kbdintctxt->ctxt == NULL)
284 fatal("input_userauth_info_response: no kbdintctxt");
285 if (kbdintctxt->device == NULL)
286 fatal("input_userauth_info_response: no device");
59c97189 287
288 authctxt->postponed = 0; /* reset */
289 nresp = packet_get_int();
477edc5d 290 if (nresp != kbdintctxt->nreq)
291 fatal("input_userauth_info_response: wrong number of replies");
292 if (nresp > 100)
293 fatal("input_userauth_info_response: too many replies");
5ba55ada 294 if (nresp > 0) {
343288b8 295 response = xmalloc(nresp * sizeof(char *));
5ba55ada 296 for (i = 0; i < nresp; i++)
297 response[i] = packet_get_string(NULL);
298 }
95500969 299 packet_check_eom();
5ba55ada 300
37ea4f91 301 res = kbdintctxt->device->respond(kbdintctxt->ctxt, nresp, response);
5ba55ada 302
303 for (i = 0; i < nresp; i++) {
304 memset(response[i], 'r', strlen(response[i]));
305 xfree(response[i]);
306 }
307 if (response)
59c97189 308 xfree(response);
5ba55ada 309
310 switch (res) {
311 case 0:
312 /* Success! */
37ea4f91 313 authenticated = authctxt->valid ? 1 : 0;
5ba55ada 314 break;
315 case 1:
316 /* Authentication needs further interaction */
2f293d43 317 if (send_userauth_info_request(authctxt) == 1)
318 authctxt->postponed = 1;
5ba55ada 319 break;
320 default:
321 /* Failure! */
322 break;
59c97189 323 }
5ba55ada 324
325 len = strlen("keyboard-interactive") + 2 +
326 strlen(kbdintctxt->device->name);
327 method = xmalloc(len);
bd2d2ac4 328 snprintf(method, len, "keyboard-interactive/%s",
329 kbdintctxt->device->name);
5ba55ada 330
331 if (!authctxt->postponed) {
5ba55ada 332 if (authenticated) {
2f293d43 333 auth2_challenge_stop(authctxt);
5ba55ada 334 } else {
335 /* start next device */
336 /* may set authctxt->postponed */
337 auth2_challenge_start(authctxt);
338 }
339 }
d9cd3575 340 userauth_finish(authctxt, authenticated, method);
5ba55ada 341 xfree(method);
59c97189 342}
1853d1ef 343
344void
345privsep_challenge_enable(void)
346{
4881aebb 347#if defined(BSD_AUTH) || defined(USE_PAM) || defined(SKEY)
348 int n = 0;
349#endif
1853d1ef 350#ifdef BSD_AUTH
351 extern KbdintDevice mm_bsdauth_device;
352#endif
05114c74 353#ifdef USE_PAM
354 extern KbdintDevice mm_sshpam_device;
355#endif
1853d1ef 356#ifdef SKEY
357 extern KbdintDevice mm_skey_device;
358#endif
05114c74 359
1853d1ef 360#ifdef BSD_AUTH
05114c74 361 devices[n++] = &mm_bsdauth_device;
1853d1ef 362#else
05114c74 363#ifdef USE_PAM
364 devices[n++] = &mm_sshpam_device;
365#endif
1853d1ef 366#ifdef SKEY
05114c74 367 devices[n++] = &mm_skey_device;
1853d1ef 368#endif
369#endif
370}
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