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3c0ef626 | 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" | |
665a873d | 26 | RCSID("$OpenBSD: auth2-chall.c,v 1.24 2005/07/17 07:17:54 djm Exp $"); |
3c0ef626 | 27 | |
28 | #include "ssh2.h" | |
29 | #include "auth.h" | |
e9a17296 | 30 | #include "buffer.h" |
3c0ef626 | 31 | #include "packet.h" |
32 | #include "xmalloc.h" | |
33 | #include "dispatch.h" | |
3c0ef626 | 34 | #include "log.h" |
996d5e62 | 35 | #include "servconf.h" |
36 | ||
37 | /* import */ | |
38 | extern ServerOptions options; | |
3c0ef626 | 39 | |
40 | static int auth2_challenge_start(Authctxt *); | |
41 | static int send_userauth_info_request(Authctxt *); | |
e9a17296 | 42 | static void input_userauth_info_response(int, u_int32_t, void *); |
3c0ef626 | 43 | |
44 | #ifdef BSD_AUTH | |
45 | extern KbdintDevice bsdauth_device; | |
46 | #else | |
0fff78ff | 47 | #ifdef USE_PAM |
48 | extern KbdintDevice sshpam_device; | |
49 | #endif | |
3c0ef626 | 50 | #ifdef SKEY |
51 | extern KbdintDevice skey_device; | |
52 | #endif | |
53 | #endif | |
54 | ||
55 | KbdintDevice *devices[] = { | |
56 | #ifdef BSD_AUTH | |
57 | &bsdauth_device, | |
58 | #else | |
0fff78ff | 59 | #ifdef USE_PAM |
60 | &sshpam_device, | |
61 | #endif | |
3c0ef626 | 62 | #ifdef SKEY |
63 | &skey_device, | |
64 | #endif | |
65 | #endif | |
66 | NULL | |
67 | }; | |
68 | ||
69 | typedef struct KbdintAuthctxt KbdintAuthctxt; | |
70 | struct KbdintAuthctxt | |
71 | { | |
72 | char *devices; | |
73 | void *ctxt; | |
74 | KbdintDevice *device; | |
680cee3b | 75 | u_int nreq; |
3c0ef626 | 76 | }; |
77 | ||
996d5e62 | 78 | #ifdef USE_PAM |
79 | void | |
80 | remove_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 | ||
3c0ef626 | 93 | static KbdintAuthctxt * |
94 | kbdint_alloc(const char *devs) | |
95 | { | |
96 | KbdintAuthctxt *kbdintctxt; | |
e9a17296 | 97 | Buffer b; |
3c0ef626 | 98 | int i; |
3c0ef626 | 99 | |
996d5e62 | 100 | #ifdef USE_PAM |
101 | if (!options.use_pam) | |
102 | remove_kbdint_device("pam"); | |
103 | #endif | |
104 | ||
3c0ef626 | 105 | kbdintctxt = xmalloc(sizeof(KbdintAuthctxt)); |
106 | if (strcmp(devs, "") == 0) { | |
e9a17296 | 107 | buffer_init(&b); |
3c0ef626 | 108 | for (i = 0; devices[i]; i++) { |
e9a17296 | 109 | if (buffer_len(&b) > 0) |
110 | buffer_append(&b, ",", 1); | |
111 | buffer_append(&b, devices[i]->name, | |
112 | strlen(devices[i]->name)); | |
3c0ef626 | 113 | } |
e9a17296 | 114 | buffer_append(&b, "\0", 1); |
115 | kbdintctxt->devices = xstrdup(buffer_ptr(&b)); | |
116 | buffer_free(&b); | |
3c0ef626 | 117 | } else { |
118 | kbdintctxt->devices = xstrdup(devs); | |
119 | } | |
e9a17296 | 120 | debug("kbdint_alloc: devices '%s'", kbdintctxt->devices); |
3c0ef626 | 121 | kbdintctxt->ctxt = NULL; |
122 | kbdintctxt->device = NULL; | |
680cee3b | 123 | kbdintctxt->nreq = 0; |
3c0ef626 | 124 | |
125 | return kbdintctxt; | |
126 | } | |
127 | static void | |
128 | kbdint_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 | } | |
136 | static void | |
137 | kbdint_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 */ | |
148 | static int | |
149 | kbdint_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 ? | |
665a873d | 170 | kbdintctxt->devices : "<empty>"); |
3c0ef626 | 171 | } while (kbdintctxt->devices && !kbdintctxt->device); |
172 | ||
173 | return kbdintctxt->device ? 1 : 0; | |
174 | } | |
175 | ||
176 | /* | |
177 | * try challenge-response, set authctxt->postponed if we have to | |
178 | * wait for the response. | |
179 | */ | |
180 | int | |
181 | auth2_challenge(Authctxt *authctxt, char *devs) | |
182 | { | |
183 | debug("auth2_challenge: user=%s devs=%s", | |
184 | authctxt->user ? authctxt->user : "<nouser>", | |
185 | devs ? devs : "<no devs>"); | |
186 | ||
187 | if (authctxt->user == NULL || !devs) | |
188 | return 0; | |
e9a17296 | 189 | if (authctxt->kbdintctxt == NULL) |
3c0ef626 | 190 | authctxt->kbdintctxt = kbdint_alloc(devs); |
191 | return auth2_challenge_start(authctxt); | |
192 | } | |
193 | ||
e9a17296 | 194 | /* unregister kbd-int callbacks and context */ |
195 | void | |
196 | auth2_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 | ||
3c0ef626 | 206 | /* side effect: sets authctxt->postponed if a reply was sent*/ |
207 | static int | |
208 | auth2_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) { | |
e9a17296 | 216 | auth2_challenge_stop(authctxt); |
3c0ef626 | 217 | return 0; |
218 | } | |
219 | debug("auth2_challenge_start: trying authentication method '%s'", | |
220 | kbdintctxt->device->name); | |
221 | ||
222 | if ((kbdintctxt->ctxt = kbdintctxt->device->init_ctx(authctxt)) == NULL) { | |
e9a17296 | 223 | auth2_challenge_stop(authctxt); |
3c0ef626 | 224 | return 0; |
225 | } | |
226 | if (send_userauth_info_request(authctxt) == 0) { | |
e9a17296 | 227 | auth2_challenge_stop(authctxt); |
3c0ef626 | 228 | return 0; |
229 | } | |
230 | dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, | |
231 | &input_userauth_info_response); | |
232 | ||
233 | authctxt->postponed = 1; | |
234 | return 0; | |
235 | } | |
236 | ||
237 | static int | |
238 | send_userauth_info_request(Authctxt *authctxt) | |
239 | { | |
240 | KbdintAuthctxt *kbdintctxt; | |
241 | char *name, *instr, **prompts; | |
665a873d | 242 | u_int i, *echo_on; |
3c0ef626 | 243 | |
244 | kbdintctxt = authctxt->kbdintctxt; | |
245 | if (kbdintctxt->device->query(kbdintctxt->ctxt, | |
680cee3b | 246 | &name, &instr, &kbdintctxt->nreq, &prompts, &echo_on)) |
3c0ef626 | 247 | return 0; |
248 | ||
249 | packet_start(SSH2_MSG_USERAUTH_INFO_REQUEST); | |
250 | packet_put_cstring(name); | |
251 | packet_put_cstring(instr); | |
f5799ae1 | 252 | packet_put_cstring(""); /* language not used */ |
680cee3b | 253 | packet_put_int(kbdintctxt->nreq); |
254 | for (i = 0; i < kbdintctxt->nreq; i++) { | |
3c0ef626 | 255 | packet_put_cstring(prompts[i]); |
256 | packet_put_char(echo_on[i]); | |
257 | } | |
258 | packet_send(); | |
259 | packet_write_wait(); | |
260 | ||
680cee3b | 261 | for (i = 0; i < kbdintctxt->nreq; i++) |
3c0ef626 | 262 | xfree(prompts[i]); |
263 | xfree(prompts); | |
264 | xfree(echo_on); | |
265 | xfree(name); | |
266 | xfree(instr); | |
267 | return 1; | |
268 | } | |
269 | ||
270 | static void | |
e9a17296 | 271 | input_userauth_info_response(int type, u_int32_t seq, void *ctxt) |
3c0ef626 | 272 | { |
273 | Authctxt *authctxt = ctxt; | |
274 | KbdintAuthctxt *kbdintctxt; | |
665a873d | 275 | int authenticated = 0, res, len; |
276 | u_int i, nresp; | |
3c0ef626 | 277 | char **response = NULL, *method; |
278 | ||
279 | if (authctxt == NULL) | |
280 | fatal("input_userauth_info_response: no authctxt"); | |
281 | kbdintctxt = authctxt->kbdintctxt; | |
282 | if (kbdintctxt == NULL || kbdintctxt->ctxt == NULL) | |
283 | fatal("input_userauth_info_response: no kbdintctxt"); | |
284 | if (kbdintctxt->device == NULL) | |
285 | fatal("input_userauth_info_response: no device"); | |
286 | ||
287 | authctxt->postponed = 0; /* reset */ | |
288 | nresp = packet_get_int(); | |
680cee3b | 289 | if (nresp != kbdintctxt->nreq) |
290 | fatal("input_userauth_info_response: wrong number of replies"); | |
291 | if (nresp > 100) | |
292 | fatal("input_userauth_info_response: too many replies"); | |
3c0ef626 | 293 | if (nresp > 0) { |
41b2f314 | 294 | response = xmalloc(nresp * sizeof(char *)); |
3c0ef626 | 295 | for (i = 0; i < nresp; i++) |
296 | response[i] = packet_get_string(NULL); | |
297 | } | |
e9a17296 | 298 | packet_check_eom(); |
3c0ef626 | 299 | |
996d5e62 | 300 | res = kbdintctxt->device->respond(kbdintctxt->ctxt, nresp, response); |
3c0ef626 | 301 | |
302 | for (i = 0; i < nresp; i++) { | |
303 | memset(response[i], 'r', strlen(response[i])); | |
304 | xfree(response[i]); | |
305 | } | |
306 | if (response) | |
307 | xfree(response); | |
308 | ||
309 | switch (res) { | |
310 | case 0: | |
311 | /* Success! */ | |
996d5e62 | 312 | authenticated = authctxt->valid ? 1 : 0; |
3c0ef626 | 313 | break; |
314 | case 1: | |
315 | /* Authentication needs further interaction */ | |
e9a17296 | 316 | if (send_userauth_info_request(authctxt) == 1) |
317 | authctxt->postponed = 1; | |
3c0ef626 | 318 | break; |
319 | default: | |
320 | /* Failure! */ | |
321 | break; | |
322 | } | |
323 | ||
324 | len = strlen("keyboard-interactive") + 2 + | |
325 | strlen(kbdintctxt->device->name); | |
326 | method = xmalloc(len); | |
e9a17296 | 327 | snprintf(method, len, "keyboard-interactive/%s", |
328 | kbdintctxt->device->name); | |
3c0ef626 | 329 | |
330 | if (!authctxt->postponed) { | |
3c0ef626 | 331 | if (authenticated) { |
e9a17296 | 332 | auth2_challenge_stop(authctxt); |
3c0ef626 | 333 | } else { |
334 | /* start next device */ | |
335 | /* may set authctxt->postponed */ | |
336 | auth2_challenge_start(authctxt); | |
337 | } | |
338 | } | |
339 | userauth_finish(authctxt, authenticated, method); | |
340 | xfree(method); | |
341 | } | |
700318f3 | 342 | |
343 | void | |
344 | privsep_challenge_enable(void) | |
345 | { | |
0fff78ff | 346 | #if defined(BSD_AUTH) || defined(USE_PAM) || defined(SKEY) |
347 | int n = 0; | |
348 | #endif | |
700318f3 | 349 | #ifdef BSD_AUTH |
350 | extern KbdintDevice mm_bsdauth_device; | |
351 | #endif | |
0fff78ff | 352 | #ifdef USE_PAM |
353 | extern KbdintDevice mm_sshpam_device; | |
354 | #endif | |
700318f3 | 355 | #ifdef SKEY |
356 | extern KbdintDevice mm_skey_device; | |
357 | #endif | |
0fff78ff | 358 | |
700318f3 | 359 | #ifdef BSD_AUTH |
0fff78ff | 360 | devices[n++] = &mm_bsdauth_device; |
700318f3 | 361 | #else |
0fff78ff | 362 | #ifdef USE_PAM |
363 | devices[n++] = &mm_sshpam_device; | |
364 | #endif | |
700318f3 | 365 | #ifdef SKEY |
0fff78ff | 366 | devices[n++] = &mm_skey_device; |
700318f3 | 367 | #endif |
368 | #endif | |
369 | } |