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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" | |
26 | RCSID("$OpenBSD: auth2-chall.c,v 1.8 2001/09/27 15:31:17 markus Exp $"); | |
27 | ||
28 | #include "ssh2.h" | |
29 | #include "auth.h" | |
30 | #include "packet.h" | |
31 | #include "xmalloc.h" | |
32 | #include "dispatch.h" | |
33 | #include "auth.h" | |
34 | #include "log.h" | |
35 | ||
36 | static int auth2_challenge_start(Authctxt *); | |
37 | static int send_userauth_info_request(Authctxt *); | |
38 | static void input_userauth_info_response(int, int, void *); | |
39 | ||
40 | #ifdef BSD_AUTH | |
41 | extern KbdintDevice bsdauth_device; | |
42 | #else | |
43 | #ifdef SKEY | |
44 | extern KbdintDevice skey_device; | |
45 | #endif | |
46 | #endif | |
47 | ||
48 | KbdintDevice *devices[] = { | |
49 | #ifdef BSD_AUTH | |
50 | &bsdauth_device, | |
51 | #else | |
52 | #ifdef SKEY | |
53 | &skey_device, | |
54 | #endif | |
55 | #endif | |
56 | NULL | |
57 | }; | |
58 | ||
59 | typedef struct KbdintAuthctxt KbdintAuthctxt; | |
60 | struct KbdintAuthctxt | |
61 | { | |
62 | char *devices; | |
63 | void *ctxt; | |
64 | KbdintDevice *device; | |
65 | }; | |
66 | ||
67 | static KbdintAuthctxt * | |
68 | kbdint_alloc(const char *devs) | |
69 | { | |
70 | KbdintAuthctxt *kbdintctxt; | |
71 | int i; | |
72 | char buf[1024]; | |
73 | ||
74 | kbdintctxt = xmalloc(sizeof(KbdintAuthctxt)); | |
75 | if (strcmp(devs, "") == 0) { | |
76 | buf[0] = '\0'; | |
77 | for (i = 0; devices[i]; i++) { | |
78 | if (i != 0) | |
79 | strlcat(buf, ",", sizeof(buf)); | |
80 | strlcat(buf, devices[i]->name, sizeof(buf)); | |
81 | } | |
82 | debug("kbdint_alloc: devices '%s'", buf); | |
83 | kbdintctxt->devices = xstrdup(buf); | |
84 | } else { | |
85 | kbdintctxt->devices = xstrdup(devs); | |
86 | } | |
87 | kbdintctxt->ctxt = NULL; | |
88 | kbdintctxt->device = NULL; | |
89 | ||
90 | return kbdintctxt; | |
91 | } | |
92 | static void | |
93 | kbdint_reset_device(KbdintAuthctxt *kbdintctxt) | |
94 | { | |
95 | if (kbdintctxt->ctxt) { | |
96 | kbdintctxt->device->free_ctx(kbdintctxt->ctxt); | |
97 | kbdintctxt->ctxt = NULL; | |
98 | } | |
99 | kbdintctxt->device = NULL; | |
100 | } | |
101 | static void | |
102 | kbdint_free(KbdintAuthctxt *kbdintctxt) | |
103 | { | |
104 | if (kbdintctxt->device) | |
105 | kbdint_reset_device(kbdintctxt); | |
106 | if (kbdintctxt->devices) { | |
107 | xfree(kbdintctxt->devices); | |
108 | kbdintctxt->devices = NULL; | |
109 | } | |
110 | xfree(kbdintctxt); | |
111 | } | |
112 | /* get next device */ | |
113 | static int | |
114 | kbdint_next_device(KbdintAuthctxt *kbdintctxt) | |
115 | { | |
116 | size_t len; | |
117 | char *t; | |
118 | int i; | |
119 | ||
120 | if (kbdintctxt->device) | |
121 | kbdint_reset_device(kbdintctxt); | |
122 | do { | |
123 | len = kbdintctxt->devices ? | |
124 | strcspn(kbdintctxt->devices, ",") : 0; | |
125 | ||
126 | if (len == 0) | |
127 | break; | |
128 | for (i = 0; devices[i]; i++) | |
129 | if (strncmp(kbdintctxt->devices, devices[i]->name, len) == 0) | |
130 | kbdintctxt->device = devices[i]; | |
131 | t = kbdintctxt->devices; | |
132 | kbdintctxt->devices = t[len] ? xstrdup(t+len+1) : NULL; | |
133 | xfree(t); | |
134 | debug2("kbdint_next_device: devices %s", kbdintctxt->devices ? | |
135 | kbdintctxt->devices : "<empty>"); | |
136 | } while (kbdintctxt->devices && !kbdintctxt->device); | |
137 | ||
138 | return kbdintctxt->device ? 1 : 0; | |
139 | } | |
140 | ||
141 | /* | |
142 | * try challenge-response, set authctxt->postponed if we have to | |
143 | * wait for the response. | |
144 | */ | |
145 | int | |
146 | auth2_challenge(Authctxt *authctxt, char *devs) | |
147 | { | |
148 | debug("auth2_challenge: user=%s devs=%s", | |
149 | authctxt->user ? authctxt->user : "<nouser>", | |
150 | devs ? devs : "<no devs>"); | |
151 | ||
152 | if (authctxt->user == NULL || !devs) | |
153 | return 0; | |
154 | if (authctxt->kbdintctxt == NULL) | |
155 | authctxt->kbdintctxt = kbdint_alloc(devs); | |
156 | return auth2_challenge_start(authctxt); | |
157 | } | |
158 | ||
159 | /* side effect: sets authctxt->postponed if a reply was sent*/ | |
160 | static int | |
161 | auth2_challenge_start(Authctxt *authctxt) | |
162 | { | |
163 | KbdintAuthctxt *kbdintctxt = authctxt->kbdintctxt; | |
164 | ||
165 | debug2("auth2_challenge_start: devices %s", | |
166 | kbdintctxt->devices ? kbdintctxt->devices : "<empty>"); | |
167 | ||
168 | if (kbdint_next_device(kbdintctxt) == 0) { | |
169 | kbdint_free(kbdintctxt); | |
170 | authctxt->kbdintctxt = NULL; | |
171 | return 0; | |
172 | } | |
173 | debug("auth2_challenge_start: trying authentication method '%s'", | |
174 | kbdintctxt->device->name); | |
175 | ||
176 | if ((kbdintctxt->ctxt = kbdintctxt->device->init_ctx(authctxt)) == NULL) { | |
177 | kbdint_free(kbdintctxt); | |
178 | authctxt->kbdintctxt = NULL; | |
179 | return 0; | |
180 | } | |
181 | if (send_userauth_info_request(authctxt) == 0) { | |
182 | kbdint_free(kbdintctxt); | |
183 | authctxt->kbdintctxt = NULL; | |
184 | return 0; | |
185 | } | |
186 | dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, | |
187 | &input_userauth_info_response); | |
188 | ||
189 | authctxt->postponed = 1; | |
190 | return 0; | |
191 | } | |
192 | ||
193 | static int | |
194 | send_userauth_info_request(Authctxt *authctxt) | |
195 | { | |
196 | KbdintAuthctxt *kbdintctxt; | |
197 | char *name, *instr, **prompts; | |
198 | int i; | |
199 | u_int numprompts, *echo_on; | |
200 | ||
201 | kbdintctxt = authctxt->kbdintctxt; | |
202 | if (kbdintctxt->device->query(kbdintctxt->ctxt, | |
203 | &name, &instr, &numprompts, &prompts, &echo_on)) | |
204 | return 0; | |
205 | ||
206 | packet_start(SSH2_MSG_USERAUTH_INFO_REQUEST); | |
207 | packet_put_cstring(name); | |
208 | packet_put_cstring(instr); | |
209 | packet_put_cstring(""); /* language not used */ | |
210 | packet_put_int(numprompts); | |
211 | for (i = 0; i < numprompts; i++) { | |
212 | packet_put_cstring(prompts[i]); | |
213 | packet_put_char(echo_on[i]); | |
214 | } | |
215 | packet_send(); | |
216 | packet_write_wait(); | |
217 | ||
218 | for (i = 0; i < numprompts; i++) | |
219 | xfree(prompts[i]); | |
220 | xfree(prompts); | |
221 | xfree(echo_on); | |
222 | xfree(name); | |
223 | xfree(instr); | |
224 | return 1; | |
225 | } | |
226 | ||
227 | static void | |
228 | input_userauth_info_response(int type, int plen, void *ctxt) | |
229 | { | |
230 | Authctxt *authctxt = ctxt; | |
231 | KbdintAuthctxt *kbdintctxt; | |
232 | int i, authenticated = 0, res, len; | |
233 | u_int nresp; | |
234 | char **response = NULL, *method; | |
235 | ||
236 | if (authctxt == NULL) | |
237 | fatal("input_userauth_info_response: no authctxt"); | |
238 | kbdintctxt = authctxt->kbdintctxt; | |
239 | if (kbdintctxt == NULL || kbdintctxt->ctxt == NULL) | |
240 | fatal("input_userauth_info_response: no kbdintctxt"); | |
241 | if (kbdintctxt->device == NULL) | |
242 | fatal("input_userauth_info_response: no device"); | |
243 | ||
244 | authctxt->postponed = 0; /* reset */ | |
245 | nresp = packet_get_int(); | |
246 | if (nresp > 0) { | |
247 | response = xmalloc(nresp * sizeof(char*)); | |
248 | for (i = 0; i < nresp; i++) | |
249 | response[i] = packet_get_string(NULL); | |
250 | } | |
251 | packet_done(); | |
252 | ||
253 | if (authctxt->valid) { | |
254 | res = kbdintctxt->device->respond(kbdintctxt->ctxt, | |
255 | nresp, response); | |
256 | } else { | |
257 | res = -1; | |
258 | } | |
259 | ||
260 | for (i = 0; i < nresp; i++) { | |
261 | memset(response[i], 'r', strlen(response[i])); | |
262 | xfree(response[i]); | |
263 | } | |
264 | if (response) | |
265 | xfree(response); | |
266 | ||
267 | switch (res) { | |
268 | case 0: | |
269 | /* Success! */ | |
270 | authenticated = 1; | |
271 | break; | |
272 | case 1: | |
273 | /* Authentication needs further interaction */ | |
274 | authctxt->postponed = 1; | |
275 | if (send_userauth_info_request(authctxt) == 0) { | |
276 | authctxt->postponed = 0; | |
277 | } | |
278 | break; | |
279 | default: | |
280 | /* Failure! */ | |
281 | break; | |
282 | } | |
283 | ||
284 | len = strlen("keyboard-interactive") + 2 + | |
285 | strlen(kbdintctxt->device->name); | |
286 | method = xmalloc(len); | |
287 | method[0] = '\0'; | |
288 | strlcat(method, "keyboard-interactive", len); | |
289 | strlcat(method, "/", len); | |
290 | strlcat(method, kbdintctxt->device->name, len); | |
291 | ||
292 | if (!authctxt->postponed) { | |
293 | /* unregister callback */ | |
294 | dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, NULL); | |
295 | ||
296 | if (authenticated) { | |
297 | kbdint_free(kbdintctxt); | |
298 | authctxt->kbdintctxt = NULL; | |
299 | } else { | |
300 | /* start next device */ | |
301 | /* may set authctxt->postponed */ | |
302 | auth2_challenge_start(authctxt); | |
303 | } | |
304 | } | |
305 | userauth_finish(authctxt, authenticated, method); | |
306 | xfree(method); | |
307 | } |