1/*
2 * Copyright (c) 2001 Markus Friedl. All rights reserved.
3 * Copyright (c) 2001 Per Allansson. All rights reserved.
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"
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26RCSID("$OpenBSD: auth2-chall.c,v 1.21 2004/06/01 14:20:45 dtucker Exp $");
27RCSID("$FreeBSD: head/crypto/openssh/auth2-chall.c 137019 2004-10-28 16:11:31Z des $");
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26RCSID("$OpenBSD: auth2-chall.c,v 1.22 2005/01/19 13:11:47 dtucker Exp $");
27RCSID("$FreeBSD: head/crypto/openssh/auth2-chall.c 147005 2005-06-05 15:46:09Z des $"); |
28
29#include "ssh2.h"
30#include "auth.h"
31#include "buffer.h"
32#include "packet.h"
33#include "xmalloc.h"
34#include "dispatch.h"
35#include "log.h"
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| 36#include "servconf.h" |
37
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38/* import */
39extern ServerOptions options;
40 |
41static int auth2_challenge_start(Authctxt *);
42static int send_userauth_info_request(Authctxt *);
43static void input_userauth_info_response(int, u_int32_t, void *);
44
45#ifdef BSD_AUTH
46extern KbdintDevice bsdauth_device;
47#else
48#ifdef USE_PAM
49extern KbdintDevice sshpam_device;
50#endif
51#ifdef SKEY
52extern KbdintDevice skey_device;
53#endif
54#endif
55
56KbdintDevice *devices[] = {
57#ifdef BSD_AUTH
58 &bsdauth_device,
59#else
60#ifdef USE_PAM
61 &sshpam_device,
62#endif
63#ifdef SKEY
64 &skey_device,
65#endif
66#endif
67 NULL
68};
69
70typedef struct KbdintAuthctxt KbdintAuthctxt;
71struct KbdintAuthctxt
72{
73 char *devices;
74 void *ctxt;
75 KbdintDevice *device;
76 u_int nreq;
77};
78
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79#ifdef USE_PAM
80void
81remove_kbdint_device(const char *devname)
82{
83 int i, j;
84
85 for (i = 0; devices[i] != NULL; i++)
86 if (strcmp(devices[i]->name, devname) == 0) {
87 for (j = i; devices[j] != NULL; j++)
88 devices[j] = devices[j+1];
89 i--;
90 }
91}
92#endif
93 |
94static KbdintAuthctxt *
95kbdint_alloc(const char *devs)
96{
97 KbdintAuthctxt *kbdintctxt;
98 Buffer b;
99 int i;
100
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101#ifdef USE_PAM
102 if (!options.use_pam)
103 remove_kbdint_device("pam");
104#endif
105 |
106 kbdintctxt = xmalloc(sizeof(KbdintAuthctxt));
107 if (strcmp(devs, "") == 0) {
108 buffer_init(&b);
109 for (i = 0; devices[i]; i++) {
110 if (buffer_len(&b) > 0)
111 buffer_append(&b, ",", 1);
112 buffer_append(&b, devices[i]->name,
113 strlen(devices[i]->name));
114 }
115 buffer_append(&b, "\0", 1);
116 kbdintctxt->devices = xstrdup(buffer_ptr(&b));
117 buffer_free(&b);
118 } else {
119 kbdintctxt->devices = xstrdup(devs);
120 }
121 debug("kbdint_alloc: devices '%s'", kbdintctxt->devices);
122 kbdintctxt->ctxt = NULL;
123 kbdintctxt->device = NULL;
124 kbdintctxt->nreq = 0;
125
126 return kbdintctxt;
127}
128static void
129kbdint_reset_device(KbdintAuthctxt *kbdintctxt)
130{
131 if (kbdintctxt->ctxt) {
132 kbdintctxt->device->free_ctx(kbdintctxt->ctxt);
133 kbdintctxt->ctxt = NULL;
134 }
135 kbdintctxt->device = NULL;
136}
137static void
138kbdint_free(KbdintAuthctxt *kbdintctxt)
139{
140 if (kbdintctxt->device)
141 kbdint_reset_device(kbdintctxt);
142 if (kbdintctxt->devices) {
143 xfree(kbdintctxt->devices);
144 kbdintctxt->devices = NULL;
145 }
146 xfree(kbdintctxt);
147}
148/* get next device */
149static int
150kbdint_next_device(KbdintAuthctxt *kbdintctxt)
151{
152 size_t len;
153 char *t;
154 int i;
155
156 if (kbdintctxt->device)
157 kbdint_reset_device(kbdintctxt);
158 do {
159 len = kbdintctxt->devices ?
160 strcspn(kbdintctxt->devices, ",") : 0;
161
162 if (len == 0)
163 break;
164 for (i = 0; devices[i]; i++)
165 if (strncmp(kbdintctxt->devices, devices[i]->name, len) == 0)
166 kbdintctxt->device = devices[i];
167 t = kbdintctxt->devices;
168 kbdintctxt->devices = t[len] ? xstrdup(t+len+1) : NULL;
169 xfree(t);
170 debug2("kbdint_next_device: devices %s", kbdintctxt->devices ?
171 kbdintctxt->devices : "<empty>");
172 } while (kbdintctxt->devices && !kbdintctxt->device);
173
174 return kbdintctxt->device ? 1 : 0;
175}
176
177/*
178 * try challenge-response, set authctxt->postponed if we have to
179 * wait for the response.
180 */
181int
182auth2_challenge(Authctxt *authctxt, char *devs)
183{
184 debug("auth2_challenge: user=%s devs=%s",
185 authctxt->user ? authctxt->user : "<nouser>",
186 devs ? devs : "<no devs>");
187
188 if (authctxt->user == NULL || !devs)
189 return 0;
190 if (authctxt->kbdintctxt == NULL)
191 authctxt->kbdintctxt = kbdint_alloc(devs);
192 return auth2_challenge_start(authctxt);
193}
194
195/* unregister kbd-int callbacks and context */
196void
197auth2_challenge_stop(Authctxt *authctxt)
198{
199 /* unregister callback */
200 dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, NULL);
201 if (authctxt->kbdintctxt != NULL) {
202 kbdint_free(authctxt->kbdintctxt);
203 authctxt->kbdintctxt = NULL;
204 }
205}
206
207/* side effect: sets authctxt->postponed if a reply was sent*/
208static int
209auth2_challenge_start(Authctxt *authctxt)
210{
211 KbdintAuthctxt *kbdintctxt = authctxt->kbdintctxt;
212
213 debug2("auth2_challenge_start: devices %s",
214 kbdintctxt->devices ? kbdintctxt->devices : "<empty>");
215
216 if (kbdint_next_device(kbdintctxt) == 0) {
217 auth2_challenge_stop(authctxt);
218 return 0;
219 }
220 debug("auth2_challenge_start: trying authentication method '%s'",
221 kbdintctxt->device->name);
222
223 if ((kbdintctxt->ctxt = kbdintctxt->device->init_ctx(authctxt)) == NULL) {
224 auth2_challenge_stop(authctxt);
225 return 0;
226 }
227 if (send_userauth_info_request(authctxt) == 0) {
228 auth2_challenge_stop(authctxt);
229 return 0;
230 }
231 dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE,
232 &input_userauth_info_response);
233
234 authctxt->postponed = 1;
235 return 0;
236}
237
238static int
239send_userauth_info_request(Authctxt *authctxt)
240{
241 KbdintAuthctxt *kbdintctxt;
242 char *name, *instr, **prompts;
243 int i;
244 u_int *echo_on;
245
246 kbdintctxt = authctxt->kbdintctxt;
247 if (kbdintctxt->device->query(kbdintctxt->ctxt,
248 &name, &instr, &kbdintctxt->nreq, &prompts, &echo_on))
249 return 0;
250
251 packet_start(SSH2_MSG_USERAUTH_INFO_REQUEST);
252 packet_put_cstring(name);
253 packet_put_cstring(instr);
254 packet_put_cstring(""); /* language not used */
255 packet_put_int(kbdintctxt->nreq);
256 for (i = 0; i < kbdintctxt->nreq; i++) {
257 packet_put_cstring(prompts[i]);
258 packet_put_char(echo_on[i]);
259 }
260 packet_send();
261 packet_write_wait();
262
263 for (i = 0; i < kbdintctxt->nreq; i++)
264 xfree(prompts[i]);
265 xfree(prompts);
266 xfree(echo_on);
267 xfree(name);
268 xfree(instr);
269 return 1;
270}
271
272static void
273input_userauth_info_response(int type, u_int32_t seq, void *ctxt)
274{
275 Authctxt *authctxt = ctxt;
276 KbdintAuthctxt *kbdintctxt;
277 int i, authenticated = 0, res, len;
278 u_int nresp;
279 char **response = NULL, *method;
280
281 if (authctxt == NULL)
282 fatal("input_userauth_info_response: no authctxt");
283 kbdintctxt = authctxt->kbdintctxt;
284 if (kbdintctxt == NULL || kbdintctxt->ctxt == NULL)
285 fatal("input_userauth_info_response: no kbdintctxt");
286 if (kbdintctxt->device == NULL)
287 fatal("input_userauth_info_response: no device");
288
289 authctxt->postponed = 0; /* reset */
290 nresp = packet_get_int();
291 if (nresp != kbdintctxt->nreq)
292 fatal("input_userauth_info_response: wrong number of replies");
293 if (nresp > 100)
294 fatal("input_userauth_info_response: too many replies");
295 if (nresp > 0) {
296 response = xmalloc(nresp * sizeof(char *));
297 for (i = 0; i < nresp; i++)
298 response[i] = packet_get_string(NULL);
299 }
300 packet_check_eom();
301
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278 if (authctxt->valid) {
279 res = kbdintctxt->device->respond(kbdintctxt->ctxt,
280 nresp, response);
281 } else {
282 res = -1;
283 }
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| 302 res = kbdintctxt->device->respond(kbdintctxt->ctxt, nresp, response); |
303
304 for (i = 0; i < nresp; i++) {
305 memset(response[i], 'r', strlen(response[i]));
306 xfree(response[i]);
307 }
308 if (response)
309 xfree(response);
310
311 switch (res) {
312 case 0:
313 /* Success! */
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295 authenticated = 1;
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| 314 authenticated = authctxt->valid ? 1 : 0; |
315 break;
316 case 1:
317 /* Authentication needs further interaction */
318 if (send_userauth_info_request(authctxt) == 1)
319 authctxt->postponed = 1;
320 break;
321 default:
322 /* Failure! */
323 break;
324 }
325
326 len = strlen("keyboard-interactive") + 2 +
327 strlen(kbdintctxt->device->name);
328 method = xmalloc(len);
329 snprintf(method, len, "keyboard-interactive/%s",
330 kbdintctxt->device->name);
331
332 if (!authctxt->postponed) {
333 if (authenticated) {
334 auth2_challenge_stop(authctxt);
335 } else {
336 /* start next device */
337 /* may set authctxt->postponed */
338 auth2_challenge_start(authctxt);
339 }
340 }
341 userauth_finish(authctxt, authenticated, method);
342 xfree(method);
343}
344
345void
346privsep_challenge_enable(void)
347{
348#if defined(BSD_AUTH) || defined(USE_PAM) || defined(SKEY)
349 int n = 0;
350#endif
351#ifdef BSD_AUTH
352 extern KbdintDevice mm_bsdauth_device;
353#endif
354#ifdef USE_PAM
355 extern KbdintDevice mm_sshpam_device;
356#endif
357#ifdef SKEY
358 extern KbdintDevice mm_skey_device;
359#endif
360
361#ifdef BSD_AUTH
362 devices[n++] = &mm_bsdauth_device;
363#else
364#ifdef USE_PAM
365 devices[n++] = &mm_sshpam_device;
366#endif
367#ifdef SKEY
368 devices[n++] = &mm_skey_device;
369#endif
370#endif
371}
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