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[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"
7203d6bb 26RCSID("$OpenBSD: auth2-chall.c,v 1.18 2002/06/19 00:27:55 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
44#ifdef SKEY
45extern KbdintDevice skey_device;
46#endif
47#endif
48
49KbdintDevice *devices[] = {
50#ifdef BSD_AUTH
51 &bsdauth_device,
52#else
53#ifdef SKEY
54 &skey_device,
55#endif
56#endif
57 NULL
58};
59
60typedef struct KbdintAuthctxt KbdintAuthctxt;
61struct KbdintAuthctxt
62{
63 char *devices;
64 void *ctxt;
65 KbdintDevice *device;
66};
67
396c147e 68static KbdintAuthctxt *
5ba55ada 69kbdint_alloc(const char *devs)
70{
71 KbdintAuthctxt *kbdintctxt;
3469eac4 72 Buffer b;
5ba55ada 73 int i;
5ba55ada 74
75 kbdintctxt = xmalloc(sizeof(KbdintAuthctxt));
76 if (strcmp(devs, "") == 0) {
3469eac4 77 buffer_init(&b);
5ba55ada 78 for (i = 0; devices[i]; i++) {
3469eac4 79 if (buffer_len(&b) > 0)
80 buffer_append(&b, ",", 1);
81 buffer_append(&b, devices[i]->name,
82 strlen(devices[i]->name));
5ba55ada 83 }
3469eac4 84 buffer_append(&b, "\0", 1);
85 kbdintctxt->devices = xstrdup(buffer_ptr(&b));
86 buffer_free(&b);
5ba55ada 87 } else {
88 kbdintctxt->devices = xstrdup(devs);
89 }
3469eac4 90 debug("kbdint_alloc: devices '%s'", kbdintctxt->devices);
5ba55ada 91 kbdintctxt->ctxt = NULL;
92 kbdintctxt->device = NULL;
93
94 return kbdintctxt;
95}
396c147e 96static void
5ba55ada 97kbdint_reset_device(KbdintAuthctxt *kbdintctxt)
98{
99 if (kbdintctxt->ctxt) {
100 kbdintctxt->device->free_ctx(kbdintctxt->ctxt);
101 kbdintctxt->ctxt = NULL;
102 }
103 kbdintctxt->device = NULL;
104}
396c147e 105static void
5ba55ada 106kbdint_free(KbdintAuthctxt *kbdintctxt)
107{
108 if (kbdintctxt->device)
109 kbdint_reset_device(kbdintctxt);
110 if (kbdintctxt->devices) {
111 xfree(kbdintctxt->devices);
112 kbdintctxt->devices = NULL;
113 }
114 xfree(kbdintctxt);
115}
116/* get next device */
396c147e 117static int
5ba55ada 118kbdint_next_device(KbdintAuthctxt *kbdintctxt)
119{
120 size_t len;
121 char *t;
122 int i;
123
124 if (kbdintctxt->device)
125 kbdint_reset_device(kbdintctxt);
126 do {
127 len = kbdintctxt->devices ?
128 strcspn(kbdintctxt->devices, ",") : 0;
129
130 if (len == 0)
131 break;
132 for (i = 0; devices[i]; i++)
133 if (strncmp(kbdintctxt->devices, devices[i]->name, len) == 0)
134 kbdintctxt->device = devices[i];
135 t = kbdintctxt->devices;
136 kbdintctxt->devices = t[len] ? xstrdup(t+len+1) : NULL;
137 xfree(t);
138 debug2("kbdint_next_device: devices %s", kbdintctxt->devices ?
139 kbdintctxt->devices : "<empty>");
140 } while (kbdintctxt->devices && !kbdintctxt->device);
141
142 return kbdintctxt->device ? 1 : 0;
143}
59c97189 144
145/*
aa8003d6 146 * try challenge-response, set authctxt->postponed if we have to
59c97189 147 * wait for the response.
148 */
149int
150auth2_challenge(Authctxt *authctxt, char *devs)
151{
5ba55ada 152 debug("auth2_challenge: user=%s devs=%s",
153 authctxt->user ? authctxt->user : "<nouser>",
154 devs ? devs : "<no devs>");
155
f5e69c65 156 if (authctxt->user == NULL || !devs)
5ba55ada 157 return 0;
184eed6a 158 if (authctxt->kbdintctxt == NULL)
5ba55ada 159 authctxt->kbdintctxt = kbdint_alloc(devs);
160 return auth2_challenge_start(authctxt);
161}
162
2f293d43 163/* unregister kbd-int callbacks and context */
164void
165auth2_challenge_stop(Authctxt *authctxt)
166{
167 /* unregister callback */
168 dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, NULL);
169 if (authctxt->kbdintctxt != NULL) {
170 kbdint_free(authctxt->kbdintctxt);
171 authctxt->kbdintctxt = NULL;
172 }
173}
174
5ba55ada 175/* side effect: sets authctxt->postponed if a reply was sent*/
176static int
177auth2_challenge_start(Authctxt *authctxt)
178{
179 KbdintAuthctxt *kbdintctxt = authctxt->kbdintctxt;
180
181 debug2("auth2_challenge_start: devices %s",
182 kbdintctxt->devices ? kbdintctxt->devices : "<empty>");
183
184 if (kbdint_next_device(kbdintctxt) == 0) {
2f293d43 185 auth2_challenge_stop(authctxt);
5ba55ada 186 return 0;
187 }
188 debug("auth2_challenge_start: trying authentication method '%s'",
189 kbdintctxt->device->name);
59c97189 190
5ba55ada 191 if ((kbdintctxt->ctxt = kbdintctxt->device->init_ctx(authctxt)) == NULL) {
2f293d43 192 auth2_challenge_stop(authctxt);
59c97189 193 return 0;
5ba55ada 194 }
195 if (send_userauth_info_request(authctxt) == 0) {
2f293d43 196 auth2_challenge_stop(authctxt);
59c97189 197 return 0;
5ba55ada 198 }
59c97189 199 dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE,
200 &input_userauth_info_response);
5ba55ada 201
59c97189 202 authctxt->postponed = 1;
203 return 0;
204}
205
5ba55ada 206static int
207send_userauth_info_request(Authctxt *authctxt)
59c97189 208{
5ba55ada 209 KbdintAuthctxt *kbdintctxt;
210 char *name, *instr, **prompts;
211 int i;
212 u_int numprompts, *echo_on;
213
214 kbdintctxt = authctxt->kbdintctxt;
215 if (kbdintctxt->device->query(kbdintctxt->ctxt,
216 &name, &instr, &numprompts, &prompts, &echo_on))
217 return 0;
59c97189 218
219 packet_start(SSH2_MSG_USERAUTH_INFO_REQUEST);
5ba55ada 220 packet_put_cstring(name);
221 packet_put_cstring(instr);
7203d6bb 222 packet_put_cstring(""); /* language not used */
5ba55ada 223 packet_put_int(numprompts);
224 for (i = 0; i < numprompts; i++) {
225 packet_put_cstring(prompts[i]);
226 packet_put_char(echo_on[i]);
227 }
59c97189 228 packet_send();
229 packet_write_wait();
5ba55ada 230
231 for (i = 0; i < numprompts; i++)
232 xfree(prompts[i]);
233 xfree(prompts);
234 xfree(echo_on);
235 xfree(name);
236 xfree(instr);
237 return 1;
59c97189 238}
239
5ba55ada 240static void
7819b5c3 241input_userauth_info_response(int type, u_int32_t seq, void *ctxt)
59c97189 242{
243 Authctxt *authctxt = ctxt;
5ba55ada 244 KbdintAuthctxt *kbdintctxt;
245 int i, authenticated = 0, res, len;
246 u_int nresp;
247 char **response = NULL, *method;
59c97189 248
249 if (authctxt == NULL)
250 fatal("input_userauth_info_response: no authctxt");
5ba55ada 251 kbdintctxt = authctxt->kbdintctxt;
252 if (kbdintctxt == NULL || kbdintctxt->ctxt == NULL)
253 fatal("input_userauth_info_response: no kbdintctxt");
254 if (kbdintctxt->device == NULL)
255 fatal("input_userauth_info_response: no device");
59c97189 256
257 authctxt->postponed = 0; /* reset */
258 nresp = packet_get_int();
5ba55ada 259 if (nresp > 0) {
260 response = xmalloc(nresp * sizeof(char*));
261 for (i = 0; i < nresp; i++)
262 response[i] = packet_get_string(NULL);
263 }
95500969 264 packet_check_eom();
5ba55ada 265
266 if (authctxt->valid) {
267 res = kbdintctxt->device->respond(kbdintctxt->ctxt,
268 nresp, response);
269 } else {
270 res = -1;
271 }
272
273 for (i = 0; i < nresp; i++) {
274 memset(response[i], 'r', strlen(response[i]));
275 xfree(response[i]);
276 }
277 if (response)
59c97189 278 xfree(response);
5ba55ada 279
280 switch (res) {
281 case 0:
282 /* Success! */
283 authenticated = 1;
284 break;
285 case 1:
286 /* Authentication needs further interaction */
2f293d43 287 if (send_userauth_info_request(authctxt) == 1)
288 authctxt->postponed = 1;
5ba55ada 289 break;
290 default:
291 /* Failure! */
292 break;
59c97189 293 }
5ba55ada 294
295 len = strlen("keyboard-interactive") + 2 +
296 strlen(kbdintctxt->device->name);
297 method = xmalloc(len);
bd2d2ac4 298 snprintf(method, len, "keyboard-interactive/%s",
299 kbdintctxt->device->name);
5ba55ada 300
301 if (!authctxt->postponed) {
5ba55ada 302 if (authenticated) {
2f293d43 303 auth2_challenge_stop(authctxt);
5ba55ada 304 } else {
305 /* start next device */
306 /* may set authctxt->postponed */
307 auth2_challenge_start(authctxt);
308 }
309 }
d9cd3575 310 userauth_finish(authctxt, authenticated, method);
5ba55ada 311 xfree(method);
59c97189 312}
1853d1ef 313
314void
315privsep_challenge_enable(void)
316{
317#ifdef BSD_AUTH
318 extern KbdintDevice mm_bsdauth_device;
319#endif
320#ifdef SKEY
321 extern KbdintDevice mm_skey_device;
322#endif
323 /* As long as SSHv1 has devices[0] hard coded this is fine */
324#ifdef BSD_AUTH
325 devices[0] = &mm_bsdauth_device;
326#else
327#ifdef SKEY
328 devices[0] = &mm_skey_device;
329#endif
330#endif
331}
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