]> andersk Git - openssh.git/blame - auth2-chall.c
- djm@cvs.openbsd.org 2003/05/24 09:30:40
[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"
343288b8 26RCSID("$OpenBSD: auth2-chall.c,v 1.20 2002/06/30 21:59:45 deraadt 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"
5ba55ada 34#include "auth.h"
42f11eb2 35#include "log.h"
59c97189 36
396c147e 37static int auth2_challenge_start(Authctxt *);
38static int send_userauth_info_request(Authctxt *);
7819b5c3 39static void input_userauth_info_response(int, u_int32_t, void *);
5ba55ada 40
41#ifdef BSD_AUTH
42extern KbdintDevice bsdauth_device;
43#else
05114c74 44#ifdef USE_PAM
45extern KbdintDevice sshpam_device;
46#endif
5ba55ada 47#ifdef SKEY
48extern KbdintDevice skey_device;
49#endif
50#endif
51
52KbdintDevice *devices[] = {
53#ifdef BSD_AUTH
54 &bsdauth_device,
55#else
05114c74 56#ifdef USE_PAM
57 &sshpam_device,
58#endif
5ba55ada 59#ifdef SKEY
60 &skey_device,
61#endif
62#endif
63 NULL
64};
65
66typedef struct KbdintAuthctxt KbdintAuthctxt;
67struct KbdintAuthctxt
68{
69 char *devices;
70 void *ctxt;
71 KbdintDevice *device;
477edc5d 72 u_int nreq;
5ba55ada 73};
74
396c147e 75static KbdintAuthctxt *
5ba55ada 76kbdint_alloc(const char *devs)
77{
78 KbdintAuthctxt *kbdintctxt;
3469eac4 79 Buffer b;
5ba55ada 80 int i;
5ba55ada 81
82 kbdintctxt = xmalloc(sizeof(KbdintAuthctxt));
83 if (strcmp(devs, "") == 0) {
3469eac4 84 buffer_init(&b);
5ba55ada 85 for (i = 0; devices[i]; i++) {
3469eac4 86 if (buffer_len(&b) > 0)
87 buffer_append(&b, ",", 1);
88 buffer_append(&b, devices[i]->name,
89 strlen(devices[i]->name));
5ba55ada 90 }
3469eac4 91 buffer_append(&b, "\0", 1);
92 kbdintctxt->devices = xstrdup(buffer_ptr(&b));
93 buffer_free(&b);
5ba55ada 94 } else {
95 kbdintctxt->devices = xstrdup(devs);
96 }
3469eac4 97 debug("kbdint_alloc: devices '%s'", kbdintctxt->devices);
5ba55ada 98 kbdintctxt->ctxt = NULL;
99 kbdintctxt->device = NULL;
477edc5d 100 kbdintctxt->nreq = 0;
5ba55ada 101
102 return kbdintctxt;
103}
396c147e 104static void
5ba55ada 105kbdint_reset_device(KbdintAuthctxt *kbdintctxt)
106{
107 if (kbdintctxt->ctxt) {
108 kbdintctxt->device->free_ctx(kbdintctxt->ctxt);
109 kbdintctxt->ctxt = NULL;
110 }
111 kbdintctxt->device = NULL;
112}
396c147e 113static void
5ba55ada 114kbdint_free(KbdintAuthctxt *kbdintctxt)
115{
116 if (kbdintctxt->device)
117 kbdint_reset_device(kbdintctxt);
118 if (kbdintctxt->devices) {
119 xfree(kbdintctxt->devices);
120 kbdintctxt->devices = NULL;
121 }
122 xfree(kbdintctxt);
123}
124/* get next device */
396c147e 125static int
5ba55ada 126kbdint_next_device(KbdintAuthctxt *kbdintctxt)
127{
128 size_t len;
129 char *t;
130 int i;
131
132 if (kbdintctxt->device)
133 kbdint_reset_device(kbdintctxt);
134 do {
135 len = kbdintctxt->devices ?
136 strcspn(kbdintctxt->devices, ",") : 0;
137
138 if (len == 0)
139 break;
140 for (i = 0; devices[i]; i++)
141 if (strncmp(kbdintctxt->devices, devices[i]->name, len) == 0)
142 kbdintctxt->device = devices[i];
143 t = kbdintctxt->devices;
144 kbdintctxt->devices = t[len] ? xstrdup(t+len+1) : NULL;
145 xfree(t);
146 debug2("kbdint_next_device: devices %s", kbdintctxt->devices ?
147 kbdintctxt->devices : "<empty>");
148 } while (kbdintctxt->devices && !kbdintctxt->device);
149
150 return kbdintctxt->device ? 1 : 0;
151}
59c97189 152
153/*
aa8003d6 154 * try challenge-response, set authctxt->postponed if we have to
59c97189 155 * wait for the response.
156 */
157int
158auth2_challenge(Authctxt *authctxt, char *devs)
159{
5ba55ada 160 debug("auth2_challenge: user=%s devs=%s",
161 authctxt->user ? authctxt->user : "<nouser>",
162 devs ? devs : "<no devs>");
163
f5e69c65 164 if (authctxt->user == NULL || !devs)
5ba55ada 165 return 0;
184eed6a 166 if (authctxt->kbdintctxt == NULL)
5ba55ada 167 authctxt->kbdintctxt = kbdint_alloc(devs);
168 return auth2_challenge_start(authctxt);
169}
170
2f293d43 171/* unregister kbd-int callbacks and context */
172void
173auth2_challenge_stop(Authctxt *authctxt)
174{
175 /* unregister callback */
176 dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, NULL);
177 if (authctxt->kbdintctxt != NULL) {
178 kbdint_free(authctxt->kbdintctxt);
179 authctxt->kbdintctxt = NULL;
180 }
181}
182
5ba55ada 183/* side effect: sets authctxt->postponed if a reply was sent*/
184static int
185auth2_challenge_start(Authctxt *authctxt)
186{
187 KbdintAuthctxt *kbdintctxt = authctxt->kbdintctxt;
188
189 debug2("auth2_challenge_start: devices %s",
190 kbdintctxt->devices ? kbdintctxt->devices : "<empty>");
191
192 if (kbdint_next_device(kbdintctxt) == 0) {
2f293d43 193 auth2_challenge_stop(authctxt);
5ba55ada 194 return 0;
195 }
196 debug("auth2_challenge_start: trying authentication method '%s'",
197 kbdintctxt->device->name);
59c97189 198
5ba55ada 199 if ((kbdintctxt->ctxt = kbdintctxt->device->init_ctx(authctxt)) == NULL) {
2f293d43 200 auth2_challenge_stop(authctxt);
59c97189 201 return 0;
5ba55ada 202 }
203 if (send_userauth_info_request(authctxt) == 0) {
2f293d43 204 auth2_challenge_stop(authctxt);
59c97189 205 return 0;
5ba55ada 206 }
59c97189 207 dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE,
208 &input_userauth_info_response);
5ba55ada 209
59c97189 210 authctxt->postponed = 1;
211 return 0;
212}
213
5ba55ada 214static int
215send_userauth_info_request(Authctxt *authctxt)
59c97189 216{
5ba55ada 217 KbdintAuthctxt *kbdintctxt;
218 char *name, *instr, **prompts;
219 int i;
477edc5d 220 u_int *echo_on;
5ba55ada 221
222 kbdintctxt = authctxt->kbdintctxt;
223 if (kbdintctxt->device->query(kbdintctxt->ctxt,
477edc5d 224 &name, &instr, &kbdintctxt->nreq, &prompts, &echo_on))
5ba55ada 225 return 0;
59c97189 226
227 packet_start(SSH2_MSG_USERAUTH_INFO_REQUEST);
5ba55ada 228 packet_put_cstring(name);
229 packet_put_cstring(instr);
7203d6bb 230 packet_put_cstring(""); /* language not used */
477edc5d 231 packet_put_int(kbdintctxt->nreq);
232 for (i = 0; i < kbdintctxt->nreq; i++) {
5ba55ada 233 packet_put_cstring(prompts[i]);
234 packet_put_char(echo_on[i]);
235 }
59c97189 236 packet_send();
237 packet_write_wait();
5ba55ada 238
477edc5d 239 for (i = 0; i < kbdintctxt->nreq; i++)
5ba55ada 240 xfree(prompts[i]);
241 xfree(prompts);
242 xfree(echo_on);
243 xfree(name);
244 xfree(instr);
245 return 1;
59c97189 246}
247
5ba55ada 248static void
7819b5c3 249input_userauth_info_response(int type, u_int32_t seq, void *ctxt)
59c97189 250{
251 Authctxt *authctxt = ctxt;
5ba55ada 252 KbdintAuthctxt *kbdintctxt;
253 int i, authenticated = 0, res, len;
254 u_int nresp;
255 char **response = NULL, *method;
59c97189 256
257 if (authctxt == NULL)
258 fatal("input_userauth_info_response: no authctxt");
5ba55ada 259 kbdintctxt = authctxt->kbdintctxt;
260 if (kbdintctxt == NULL || kbdintctxt->ctxt == NULL)
261 fatal("input_userauth_info_response: no kbdintctxt");
262 if (kbdintctxt->device == NULL)
263 fatal("input_userauth_info_response: no device");
59c97189 264
265 authctxt->postponed = 0; /* reset */
266 nresp = packet_get_int();
477edc5d 267 if (nresp != kbdintctxt->nreq)
268 fatal("input_userauth_info_response: wrong number of replies");
269 if (nresp > 100)
270 fatal("input_userauth_info_response: too many replies");
5ba55ada 271 if (nresp > 0) {
343288b8 272 response = xmalloc(nresp * sizeof(char *));
5ba55ada 273 for (i = 0; i < nresp; i++)
274 response[i] = packet_get_string(NULL);
275 }
95500969 276 packet_check_eom();
5ba55ada 277
278 if (authctxt->valid) {
279 res = kbdintctxt->device->respond(kbdintctxt->ctxt,
280 nresp, response);
281 } else {
282 res = -1;
283 }
284
285 for (i = 0; i < nresp; i++) {
286 memset(response[i], 'r', strlen(response[i]));
287 xfree(response[i]);
288 }
289 if (response)
59c97189 290 xfree(response);
5ba55ada 291
292 switch (res) {
293 case 0:
294 /* Success! */
295 authenticated = 1;
296 break;
297 case 1:
298 /* Authentication needs further interaction */
2f293d43 299 if (send_userauth_info_request(authctxt) == 1)
300 authctxt->postponed = 1;
5ba55ada 301 break;
302 default:
303 /* Failure! */
304 break;
59c97189 305 }
5ba55ada 306
307 len = strlen("keyboard-interactive") + 2 +
308 strlen(kbdintctxt->device->name);
309 method = xmalloc(len);
bd2d2ac4 310 snprintf(method, len, "keyboard-interactive/%s",
311 kbdintctxt->device->name);
5ba55ada 312
313 if (!authctxt->postponed) {
5ba55ada 314 if (authenticated) {
2f293d43 315 auth2_challenge_stop(authctxt);
5ba55ada 316 } else {
317 /* start next device */
318 /* may set authctxt->postponed */
319 auth2_challenge_start(authctxt);
320 }
321 }
d9cd3575 322 userauth_finish(authctxt, authenticated, method);
5ba55ada 323 xfree(method);
59c97189 324}
1853d1ef 325
326void
327privsep_challenge_enable(void)
328{
329#ifdef BSD_AUTH
330 extern KbdintDevice mm_bsdauth_device;
331#endif
05114c74 332#ifdef USE_PAM
333 extern KbdintDevice mm_sshpam_device;
334#endif
1853d1ef 335#ifdef SKEY
336 extern KbdintDevice mm_skey_device;
337#endif
05114c74 338 int n = 0;
339
1853d1ef 340#ifdef BSD_AUTH
05114c74 341 devices[n++] = &mm_bsdauth_device;
1853d1ef 342#else
05114c74 343#ifdef USE_PAM
344 devices[n++] = &mm_sshpam_device;
345#endif
1853d1ef 346#ifdef SKEY
05114c74 347 devices[n++] = &mm_skey_device;
1853d1ef 348#endif
349#endif
350}
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