Annotation of src/usr.bin/ssh/auth2-chall.c, Revision 1.2.2.7
1.1 markus 1: /*
1.2.2.3 jason 2: * Copyright (c) 2001 Markus Friedl. All rights reserved.
1.2.2.5 miod 3: * Copyright (c) 2001 Per Allansson. All rights reserved.
1.1 markus 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"
1.2.2.7 ! brad 26: RCSID("$OpenBSD: auth2-chall.c,v 1.16 2002/01/13 17:57:37 markus Exp $");
1.1 markus 27:
28: #include "ssh2.h"
29: #include "auth.h"
1.2.2.7 ! brad 30: #include "buffer.h"
1.1 markus 31: #include "packet.h"
32: #include "xmalloc.h"
33: #include "dispatch.h"
1.2.2.5 miod 34: #include "auth.h"
1.2 markus 35: #include "log.h"
1.1 markus 36:
1.2.2.5 miod 37: static int auth2_challenge_start(Authctxt *);
38: static int send_userauth_info_request(Authctxt *);
1.2.2.7 ! brad 39: static void input_userauth_info_response(int, u_int32_t, void *);
1.2.2.5 miod 40:
41: #ifdef BSD_AUTH
42: extern KbdintDevice bsdauth_device;
43: #else
44: #ifdef SKEY
45: extern KbdintDevice skey_device;
46: #endif
47: #endif
48:
49: KbdintDevice *devices[] = {
50: #ifdef BSD_AUTH
51: &bsdauth_device,
52: #else
53: #ifdef SKEY
54: &skey_device,
55: #endif
56: #endif
57: NULL
58: };
59:
60: typedef struct KbdintAuthctxt KbdintAuthctxt;
61: struct KbdintAuthctxt
62: {
63: char *devices;
64: void *ctxt;
65: KbdintDevice *device;
66: };
67:
68: static KbdintAuthctxt *
69: kbdint_alloc(const char *devs)
70: {
71: KbdintAuthctxt *kbdintctxt;
1.2.2.7 ! brad 72: Buffer b;
1.2.2.5 miod 73: int i;
74:
75: kbdintctxt = xmalloc(sizeof(KbdintAuthctxt));
76: if (strcmp(devs, "") == 0) {
1.2.2.7 ! brad 77: buffer_init(&b);
1.2.2.5 miod 78: for (i = 0; devices[i]; i++) {
1.2.2.7 ! brad 79: if (buffer_len(&b) > 0)
! 80: buffer_append(&b, ",", 1);
! 81: buffer_append(&b, devices[i]->name,
! 82: strlen(devices[i]->name));
1.2.2.5 miod 83: }
1.2.2.7 ! brad 84: buffer_append(&b, "\0", 1);
! 85: kbdintctxt->devices = xstrdup(buffer_ptr(&b));
! 86: buffer_free(&b);
1.2.2.5 miod 87: } else {
88: kbdintctxt->devices = xstrdup(devs);
89: }
1.2.2.7 ! brad 90: debug("kbdint_alloc: devices '%s'", kbdintctxt->devices);
1.2.2.5 miod 91: kbdintctxt->ctxt = NULL;
92: kbdintctxt->device = NULL;
93:
94: return kbdintctxt;
95: }
96: static void
97: kbdint_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: }
105: static void
106: kbdint_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 */
117: static int
118: kbdint_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: }
1.1 markus 144:
145: /*
1.2.2.6 miod 146: * try challenge-response, set authctxt->postponed if we have to
1.1 markus 147: * wait for the response.
148: */
149: int
150: auth2_challenge(Authctxt *authctxt, char *devs)
151: {
1.2.2.5 miod 152: debug("auth2_challenge: user=%s devs=%s",
153: authctxt->user ? authctxt->user : "<nouser>",
154: devs ? devs : "<no devs>");
1.1 markus 155:
1.2.2.5 miod 156: if (authctxt->user == NULL || !devs)
1.1 markus 157: return 0;
1.2.2.7 ! brad 158: if (authctxt->kbdintctxt == NULL)
1.2.2.5 miod 159: authctxt->kbdintctxt = kbdint_alloc(devs);
160: return auth2_challenge_start(authctxt);
161: }
162:
1.2.2.7 ! brad 163: /* unregister kbd-int callbacks and context */
! 164: void
! 165: auth2_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:
1.2.2.5 miod 175: /* side effect: sets authctxt->postponed if a reply was sent*/
176: static int
177: auth2_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) {
1.2.2.7 ! brad 185: auth2_challenge_stop(authctxt);
1.2.2.5 miod 186: return 0;
187: }
188: debug("auth2_challenge_start: trying authentication method '%s'",
189: kbdintctxt->device->name);
190:
191: if ((kbdintctxt->ctxt = kbdintctxt->device->init_ctx(authctxt)) == NULL) {
1.2.2.7 ! brad 192: auth2_challenge_stop(authctxt);
1.2.2.5 miod 193: return 0;
194: }
195: if (send_userauth_info_request(authctxt) == 0) {
1.2.2.7 ! brad 196: auth2_challenge_stop(authctxt);
1.1 markus 197: return 0;
1.2.2.5 miod 198: }
1.1 markus 199: dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE,
200: &input_userauth_info_response);
1.2.2.5 miod 201:
1.1 markus 202: authctxt->postponed = 1;
203: return 0;
204: }
205:
1.2.2.5 miod 206: static int
207: send_userauth_info_request(Authctxt *authctxt)
1.1 markus 208: {
1.2.2.5 miod 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;
1.1 markus 218:
219: packet_start(SSH2_MSG_USERAUTH_INFO_REQUEST);
1.2.2.5 miod 220: packet_put_cstring(name);
221: packet_put_cstring(instr);
222: packet_put_cstring(""); /* language not used */
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: }
1.1 markus 228: packet_send();
229: packet_write_wait();
1.2.2.5 miod 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;
1.1 markus 238: }
239:
1.2.2.5 miod 240: static void
1.2.2.7 ! brad 241: input_userauth_info_response(int type, u_int32_t seq, void *ctxt)
1.1 markus 242: {
243: Authctxt *authctxt = ctxt;
1.2.2.5 miod 244: KbdintAuthctxt *kbdintctxt;
245: int i, authenticated = 0, res, len;
246: u_int nresp;
247: char **response = NULL, *method;
1.1 markus 248:
249: if (authctxt == NULL)
250: fatal("input_userauth_info_response: no authctxt");
1.2.2.5 miod 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");
1.1 markus 256:
257: authctxt->postponed = 0; /* reset */
258: nresp = packet_get_int();
1.2.2.5 miod 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: }
1.2.2.7 ! brad 264: packet_check_eom();
1.2.2.5 miod 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)
1.1 markus 278: xfree(response);
1.2.2.5 miod 279:
280: switch (res) {
281: case 0:
282: /* Success! */
283: authenticated = 1;
284: break;
285: case 1:
286: /* Authentication needs further interaction */
1.2.2.7 ! brad 287: if (send_userauth_info_request(authctxt) == 1)
! 288: authctxt->postponed = 1;
1.2.2.5 miod 289: break;
290: default:
291: /* Failure! */
292: break;
1.1 markus 293: }
1.2.2.5 miod 294:
295: len = strlen("keyboard-interactive") + 2 +
296: strlen(kbdintctxt->device->name);
297: method = xmalloc(len);
1.2.2.7 ! brad 298: snprintf(method, len, "keyboard-interactive/%s",
! 299: kbdintctxt->device->name);
1.2.2.5 miod 300:
301: if (!authctxt->postponed) {
302: if (authenticated) {
1.2.2.7 ! brad 303: auth2_challenge_stop(authctxt);
1.2.2.5 miod 304: } else {
305: /* start next device */
306: /* may set authctxt->postponed */
307: auth2_challenge_start(authctxt);
308: }
309: }
1.2.2.4 jason 310: userauth_finish(authctxt, authenticated, method);
1.2.2.5 miod 311: xfree(method);
1.1 markus 312: }
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