1 /* $OpenBSD: auth2-chall.c,v 1.31 2006/08/05 08:28:24 dtucker Exp $ */
3 * Copyright (c) 2001 Markus Friedl. All rights reserved.
4 * Copyright (c) 2001 Per Allansson. All rights reserved.
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 #include <sys/types.h>
48 extern ServerOptions options;
50 static int auth2_challenge_start(Authctxt *);
51 static int send_userauth_info_request(Authctxt *);
52 static void input_userauth_info_response(int, u_int32_t, void *);
55 extern KbdintDevice bsdauth_device;
58 extern KbdintDevice sshpam_device;
61 extern KbdintDevice skey_device;
65 KbdintDevice *devices[] = {
79 typedef struct KbdintAuthctxt KbdintAuthctxt;
90 remove_kbdint_device(const char *devname)
94 for (i = 0; devices[i] != NULL; i++)
95 if (strcmp(devices[i]->name, devname) == 0) {
96 for (j = i; devices[j] != NULL; j++)
97 devices[j] = devices[j+1];
103 static KbdintAuthctxt *
104 kbdint_alloc(const char *devs)
106 KbdintAuthctxt *kbdintctxt;
111 if (!options.use_pam)
112 remove_kbdint_device("pam");
115 kbdintctxt = xmalloc(sizeof(KbdintAuthctxt));
116 if (strcmp(devs, "") == 0) {
118 for (i = 0; devices[i]; i++) {
119 if (buffer_len(&b) > 0)
120 buffer_append(&b, ",", 1);
121 buffer_append(&b, devices[i]->name,
122 strlen(devices[i]->name));
124 buffer_append(&b, "\0", 1);
125 kbdintctxt->devices = xstrdup(buffer_ptr(&b));
128 kbdintctxt->devices = xstrdup(devs);
130 debug("kbdint_alloc: devices '%s'", kbdintctxt->devices);
131 kbdintctxt->ctxt = NULL;
132 kbdintctxt->device = NULL;
133 kbdintctxt->nreq = 0;
138 kbdint_reset_device(KbdintAuthctxt *kbdintctxt)
140 if (kbdintctxt->ctxt) {
141 kbdintctxt->device->free_ctx(kbdintctxt->ctxt);
142 kbdintctxt->ctxt = NULL;
144 kbdintctxt->device = NULL;
147 kbdint_free(KbdintAuthctxt *kbdintctxt)
149 if (kbdintctxt->device)
150 kbdint_reset_device(kbdintctxt);
151 if (kbdintctxt->devices) {
152 xfree(kbdintctxt->devices);
153 kbdintctxt->devices = NULL;
157 /* get next device */
159 kbdint_next_device(KbdintAuthctxt *kbdintctxt)
165 if (kbdintctxt->device)
166 kbdint_reset_device(kbdintctxt);
168 len = kbdintctxt->devices ?
169 strcspn(kbdintctxt->devices, ",") : 0;
173 for (i = 0; devices[i]; i++)
174 if (strncmp(kbdintctxt->devices, devices[i]->name, len) == 0)
175 kbdintctxt->device = devices[i];
176 t = kbdintctxt->devices;
177 kbdintctxt->devices = t[len] ? xstrdup(t+len+1) : NULL;
179 debug2("kbdint_next_device: devices %s", kbdintctxt->devices ?
180 kbdintctxt->devices : "<empty>");
181 } while (kbdintctxt->devices && !kbdintctxt->device);
183 return kbdintctxt->device ? 1 : 0;
187 * try challenge-response, set authctxt->postponed if we have to
188 * wait for the response.
191 auth2_challenge(Authctxt *authctxt, char *devs)
193 debug("auth2_challenge: user=%s devs=%s",
194 authctxt->user ? authctxt->user : "<nouser>",
195 devs ? devs : "<no devs>");
197 if (authctxt->user == NULL || !devs)
199 if (authctxt->kbdintctxt == NULL)
200 authctxt->kbdintctxt = kbdint_alloc(devs);
201 return auth2_challenge_start(authctxt);
204 /* unregister kbd-int callbacks and context */
206 auth2_challenge_stop(Authctxt *authctxt)
208 /* unregister callback */
209 dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, NULL);
210 if (authctxt->kbdintctxt != NULL) {
211 kbdint_free(authctxt->kbdintctxt);
212 authctxt->kbdintctxt = NULL;
216 /* side effect: sets authctxt->postponed if a reply was sent*/
218 auth2_challenge_start(Authctxt *authctxt)
220 KbdintAuthctxt *kbdintctxt = authctxt->kbdintctxt;
222 debug2("auth2_challenge_start: devices %s",
223 kbdintctxt->devices ? kbdintctxt->devices : "<empty>");
225 if (kbdint_next_device(kbdintctxt) == 0) {
226 auth2_challenge_stop(authctxt);
229 debug("auth2_challenge_start: trying authentication method '%s'",
230 kbdintctxt->device->name);
232 if ((kbdintctxt->ctxt = kbdintctxt->device->init_ctx(authctxt)) == NULL) {
233 auth2_challenge_stop(authctxt);
236 if (send_userauth_info_request(authctxt) == 0) {
237 auth2_challenge_stop(authctxt);
240 dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE,
241 &input_userauth_info_response);
243 authctxt->postponed = 1;
248 send_userauth_info_request(Authctxt *authctxt)
250 KbdintAuthctxt *kbdintctxt;
251 char *name, *instr, **prompts;
254 kbdintctxt = authctxt->kbdintctxt;
255 if (kbdintctxt->device->query(kbdintctxt->ctxt,
256 &name, &instr, &kbdintctxt->nreq, &prompts, &echo_on))
259 packet_start(SSH2_MSG_USERAUTH_INFO_REQUEST);
260 packet_put_cstring(name);
261 packet_put_cstring(instr);
262 packet_put_cstring(""); /* language not used */
263 packet_put_int(kbdintctxt->nreq);
264 for (i = 0; i < kbdintctxt->nreq; i++) {
265 packet_put_cstring(prompts[i]);
266 packet_put_char(echo_on[i]);
271 for (i = 0; i < kbdintctxt->nreq; i++)
281 input_userauth_info_response(int type, u_int32_t seq, void *ctxt)
283 Authctxt *authctxt = ctxt;
284 KbdintAuthctxt *kbdintctxt;
285 int authenticated = 0, res, len;
287 char **response = NULL, *method;
289 if (authctxt == NULL)
290 fatal("input_userauth_info_response: no authctxt");
291 kbdintctxt = authctxt->kbdintctxt;
292 if (kbdintctxt == NULL || kbdintctxt->ctxt == NULL)
293 fatal("input_userauth_info_response: no kbdintctxt");
294 if (kbdintctxt->device == NULL)
295 fatal("input_userauth_info_response: no device");
297 authctxt->postponed = 0; /* reset */
298 nresp = packet_get_int();
299 if (nresp != kbdintctxt->nreq)
300 fatal("input_userauth_info_response: wrong number of replies");
302 fatal("input_userauth_info_response: too many replies");
304 response = xcalloc(nresp, sizeof(char *));
305 for (i = 0; i < nresp; i++)
306 response[i] = packet_get_string(NULL);
310 res = kbdintctxt->device->respond(kbdintctxt->ctxt, nresp, response);
312 for (i = 0; i < nresp; i++) {
313 memset(response[i], 'r', strlen(response[i]));
322 authenticated = authctxt->valid ? 1 : 0;
325 /* Authentication needs further interaction */
326 if (send_userauth_info_request(authctxt) == 1)
327 authctxt->postponed = 1;
334 len = strlen("keyboard-interactive") + 2 +
335 strlen(kbdintctxt->device->name);
336 method = xmalloc(len);
337 snprintf(method, len, "keyboard-interactive/%s",
338 kbdintctxt->device->name);
340 if (!authctxt->postponed) {
342 auth2_challenge_stop(authctxt);
344 /* start next device */
345 /* may set authctxt->postponed */
346 auth2_challenge_start(authctxt);
349 userauth_finish(authctxt, authenticated, method);
354 privsep_challenge_enable(void)
356 #if defined(BSD_AUTH) || defined(USE_PAM) || defined(SKEY)
360 extern KbdintDevice mm_bsdauth_device;
363 extern KbdintDevice mm_sshpam_device;
366 extern KbdintDevice mm_skey_device;
370 devices[n++] = &mm_bsdauth_device;
373 devices[n++] = &mm_sshpam_device;
376 devices[n++] = &mm_skey_device;