Line data Source code
1 : /*
2 : * EAP peer method: EAP-pwd (RFC 5931)
3 : * Copyright (c) 2010, Dan Harkins <dharkins@lounge.org>
4 : *
5 : * This software may be distributed under the terms of the BSD license.
6 : * See README for more details.
7 : */
8 :
9 : #include "includes.h"
10 :
11 : #include "common.h"
12 : #include "crypto/sha256.h"
13 : #include "eap_peer/eap_i.h"
14 : #include "eap_common/eap_pwd_common.h"
15 :
16 :
17 : struct eap_pwd_data {
18 : enum {
19 : PWD_ID_Req, PWD_Commit_Req, PWD_Confirm_Req,
20 : SUCCESS_ON_FRAG_COMPLETION, SUCCESS, FAILURE
21 : } state;
22 : u8 *id_peer;
23 : size_t id_peer_len;
24 : u8 *id_server;
25 : size_t id_server_len;
26 : u8 *password;
27 : size_t password_len;
28 : u16 group_num;
29 : EAP_PWD_group *grp;
30 :
31 : struct wpabuf *inbuf;
32 : size_t in_frag_pos;
33 : struct wpabuf *outbuf;
34 : size_t out_frag_pos;
35 : size_t mtu;
36 :
37 : BIGNUM *k;
38 : BIGNUM *private_value;
39 : BIGNUM *server_scalar;
40 : BIGNUM *my_scalar;
41 : EC_POINT *my_element;
42 : EC_POINT *server_element;
43 :
44 : u8 msk[EAP_MSK_LEN];
45 : u8 emsk[EAP_EMSK_LEN];
46 : u8 session_id[1 + SHA256_MAC_LEN];
47 :
48 : BN_CTX *bnctx;
49 : };
50 :
51 :
52 : #ifndef CONFIG_NO_STDOUT_DEBUG
53 88 : static const char * eap_pwd_state_txt(int state)
54 : {
55 88 : switch (state) {
56 : case PWD_ID_Req:
57 12 : return "PWD-ID-Req";
58 : case PWD_Commit_Req:
59 22 : return "PWD-Commit-Req";
60 : case PWD_Confirm_Req:
61 22 : return "PWD-Confirm-Req";
62 : case SUCCESS_ON_FRAG_COMPLETION:
63 20 : return "SUCCESS_ON_FRAG_COMPLETION";
64 : case SUCCESS:
65 10 : return "SUCCESS";
66 : case FAILURE:
67 2 : return "FAILURE";
68 : default:
69 0 : return "PWD-UNK";
70 : }
71 : }
72 : #endif /* CONFIG_NO_STDOUT_DEBUG */
73 :
74 :
75 44 : static void eap_pwd_state(struct eap_pwd_data *data, int state)
76 : {
77 88 : wpa_printf(MSG_DEBUG, "EAP-PWD: %s -> %s",
78 44 : eap_pwd_state_txt(data->state), eap_pwd_state_txt(state));
79 44 : data->state = state;
80 44 : }
81 :
82 :
83 12 : static void * eap_pwd_init(struct eap_sm *sm)
84 : {
85 : struct eap_pwd_data *data;
86 : const u8 *identity, *password;
87 : size_t identity_len, password_len;
88 : int fragment_size;
89 :
90 12 : password = eap_get_config_password(sm, &password_len);
91 12 : if (password == NULL) {
92 0 : wpa_printf(MSG_INFO, "EAP-PWD: No password configured!");
93 0 : return NULL;
94 : }
95 :
96 12 : identity = eap_get_config_identity(sm, &identity_len);
97 12 : if (identity == NULL) {
98 0 : wpa_printf(MSG_INFO, "EAP-PWD: No identity configured!");
99 0 : return NULL;
100 : }
101 :
102 12 : if ((data = os_zalloc(sizeof(*data))) == NULL) {
103 0 : wpa_printf(MSG_INFO, "EAP-PWD: memory allocation data fail");
104 0 : return NULL;
105 : }
106 :
107 12 : if ((data->bnctx = BN_CTX_new()) == NULL) {
108 0 : wpa_printf(MSG_INFO, "EAP-PWD: bn context allocation fail");
109 0 : os_free(data);
110 0 : return NULL;
111 : }
112 :
113 12 : if ((data->id_peer = os_malloc(identity_len)) == NULL) {
114 0 : wpa_printf(MSG_INFO, "EAP-PWD: memory allocation id fail");
115 0 : BN_CTX_free(data->bnctx);
116 0 : os_free(data);
117 0 : return NULL;
118 : }
119 :
120 12 : os_memcpy(data->id_peer, identity, identity_len);
121 12 : data->id_peer_len = identity_len;
122 :
123 12 : if ((data->password = os_malloc(password_len)) == NULL) {
124 0 : wpa_printf(MSG_INFO, "EAP-PWD: memory allocation psk fail");
125 0 : BN_CTX_free(data->bnctx);
126 0 : os_free(data->id_peer);
127 0 : os_free(data);
128 0 : return NULL;
129 : }
130 12 : os_memcpy(data->password, password, password_len);
131 12 : data->password_len = password_len;
132 :
133 12 : data->out_frag_pos = data->in_frag_pos = 0;
134 12 : data->inbuf = data->outbuf = NULL;
135 12 : fragment_size = eap_get_config_fragment_size(sm);
136 12 : if (fragment_size <= 0)
137 0 : data->mtu = 1020; /* default from RFC 5931 */
138 : else
139 12 : data->mtu = fragment_size;
140 :
141 12 : data->state = PWD_ID_Req;
142 :
143 12 : return data;
144 : }
145 :
146 :
147 12 : static void eap_pwd_deinit(struct eap_sm *sm, void *priv)
148 : {
149 12 : struct eap_pwd_data *data = priv;
150 :
151 12 : BN_free(data->private_value);
152 12 : BN_free(data->server_scalar);
153 12 : BN_free(data->my_scalar);
154 12 : BN_free(data->k);
155 12 : BN_CTX_free(data->bnctx);
156 12 : EC_POINT_free(data->my_element);
157 12 : EC_POINT_free(data->server_element);
158 12 : os_free(data->id_peer);
159 12 : os_free(data->id_server);
160 12 : os_free(data->password);
161 12 : if (data->grp) {
162 12 : EC_GROUP_free(data->grp->group);
163 12 : EC_POINT_free(data->grp->pwe);
164 12 : BN_free(data->grp->order);
165 12 : BN_free(data->grp->prime);
166 12 : os_free(data->grp);
167 : }
168 12 : wpabuf_free(data->inbuf);
169 12 : wpabuf_free(data->outbuf);
170 12 : os_free(data);
171 12 : }
172 :
173 :
174 10 : static u8 * eap_pwd_getkey(struct eap_sm *sm, void *priv, size_t *len)
175 : {
176 10 : struct eap_pwd_data *data = priv;
177 : u8 *key;
178 :
179 10 : if (data->state != SUCCESS)
180 0 : return NULL;
181 :
182 10 : key = os_malloc(EAP_MSK_LEN);
183 10 : if (key == NULL)
184 0 : return NULL;
185 :
186 10 : os_memcpy(key, data->msk, EAP_MSK_LEN);
187 10 : *len = EAP_MSK_LEN;
188 :
189 10 : return key;
190 : }
191 :
192 :
193 10 : static u8 * eap_pwd_get_session_id(struct eap_sm *sm, void *priv, size_t *len)
194 : {
195 10 : struct eap_pwd_data *data = priv;
196 : u8 *id;
197 :
198 10 : if (data->state != SUCCESS)
199 0 : return NULL;
200 :
201 10 : id = os_malloc(1 + SHA256_MAC_LEN);
202 10 : if (id == NULL)
203 0 : return NULL;
204 :
205 10 : os_memcpy(id, data->session_id, 1 + SHA256_MAC_LEN);
206 10 : *len = 1 + SHA256_MAC_LEN;
207 :
208 10 : return id;
209 : }
210 :
211 :
212 : static void
213 12 : eap_pwd_perform_id_exchange(struct eap_sm *sm, struct eap_pwd_data *data,
214 : struct eap_method_ret *ret,
215 : const struct wpabuf *reqData,
216 : const u8 *payload, size_t payload_len)
217 : {
218 : struct eap_pwd_id *id;
219 :
220 12 : if (data->state != PWD_ID_Req) {
221 0 : ret->ignore = TRUE;
222 0 : eap_pwd_state(data, FAILURE);
223 0 : return;
224 : }
225 :
226 12 : if (payload_len < sizeof(struct eap_pwd_id)) {
227 0 : ret->ignore = TRUE;
228 0 : eap_pwd_state(data, FAILURE);
229 0 : return;
230 : }
231 :
232 12 : id = (struct eap_pwd_id *) payload;
233 12 : data->group_num = be_to_host16(id->group_num);
234 24 : if ((id->random_function != EAP_PWD_DEFAULT_RAND_FUNC) ||
235 12 : (id->prf != EAP_PWD_DEFAULT_PRF)) {
236 0 : ret->ignore = TRUE;
237 0 : eap_pwd_state(data, FAILURE);
238 0 : return;
239 : }
240 :
241 12 : wpa_printf(MSG_DEBUG, "EAP-PWD (peer): using group %d",
242 12 : data->group_num);
243 :
244 12 : data->id_server = os_malloc(payload_len - sizeof(struct eap_pwd_id));
245 12 : if (data->id_server == NULL) {
246 0 : wpa_printf(MSG_INFO, "EAP-PWD: memory allocation id fail");
247 0 : eap_pwd_state(data, FAILURE);
248 0 : return;
249 : }
250 12 : data->id_server_len = payload_len - sizeof(struct eap_pwd_id);
251 12 : os_memcpy(data->id_server, id->identity, data->id_server_len);
252 24 : wpa_hexdump_ascii(MSG_INFO, "EAP-PWD (peer): server sent id of",
253 12 : data->id_server, data->id_server_len);
254 :
255 12 : data->grp = os_zalloc(sizeof(EAP_PWD_group));
256 12 : if (data->grp == NULL) {
257 0 : wpa_printf(MSG_INFO, "EAP-PWD: failed to allocate memory for "
258 : "group");
259 0 : eap_pwd_state(data, FAILURE);
260 0 : return;
261 : }
262 :
263 : /* compute PWE */
264 36 : if (compute_password_element(data->grp, data->group_num,
265 12 : data->password, data->password_len,
266 12 : data->id_server, data->id_server_len,
267 12 : data->id_peer, data->id_peer_len,
268 12 : id->token)) {
269 1 : wpa_printf(MSG_INFO, "EAP-PWD (peer): unable to compute PWE");
270 1 : eap_pwd_state(data, FAILURE);
271 1 : return;
272 : }
273 :
274 11 : wpa_printf(MSG_DEBUG, "EAP-PWD (peer): computed %d bit PWE...",
275 11 : BN_num_bits(data->grp->prime));
276 :
277 11 : data->outbuf = wpabuf_alloc(sizeof(struct eap_pwd_id) +
278 11 : data->id_peer_len);
279 11 : if (data->outbuf == NULL) {
280 0 : eap_pwd_state(data, FAILURE);
281 0 : return;
282 : }
283 11 : wpabuf_put_be16(data->outbuf, data->group_num);
284 11 : wpabuf_put_u8(data->outbuf, EAP_PWD_DEFAULT_RAND_FUNC);
285 11 : wpabuf_put_u8(data->outbuf, EAP_PWD_DEFAULT_PRF);
286 11 : wpabuf_put_data(data->outbuf, id->token, sizeof(id->token));
287 11 : wpabuf_put_u8(data->outbuf, EAP_PWD_PREP_NONE);
288 11 : wpabuf_put_data(data->outbuf, data->id_peer, data->id_peer_len);
289 :
290 11 : eap_pwd_state(data, PWD_Commit_Req);
291 : }
292 :
293 :
294 : static void
295 11 : eap_pwd_perform_commit_exchange(struct eap_sm *sm, struct eap_pwd_data *data,
296 : struct eap_method_ret *ret,
297 : const struct wpabuf *reqData,
298 : const u8 *payload, size_t payload_len)
299 : {
300 11 : EC_POINT *K = NULL, *point = NULL;
301 11 : BIGNUM *mask = NULL, *x = NULL, *y = NULL, *cofactor = NULL;
302 : u16 offset;
303 11 : u8 *ptr, *scalar = NULL, *element = NULL;
304 :
305 22 : if (((data->private_value = BN_new()) == NULL) ||
306 22 : ((data->my_element = EC_POINT_new(data->grp->group)) == NULL) ||
307 11 : ((cofactor = BN_new()) == NULL) ||
308 22 : ((data->my_scalar = BN_new()) == NULL) ||
309 : ((mask = BN_new()) == NULL)) {
310 0 : wpa_printf(MSG_INFO, "EAP-PWD (peer): scalar allocation fail");
311 0 : goto fin;
312 : }
313 :
314 11 : if (!EC_GROUP_get_cofactor(data->grp->group, cofactor, NULL)) {
315 0 : wpa_printf(MSG_INFO, "EAP-pwd (peer): unable to get cofactor "
316 : "for curve");
317 0 : goto fin;
318 : }
319 :
320 11 : BN_rand_range(data->private_value, data->grp->order);
321 11 : BN_rand_range(mask, data->grp->order);
322 11 : BN_add(data->my_scalar, data->private_value, mask);
323 11 : BN_mod(data->my_scalar, data->my_scalar, data->grp->order,
324 : data->bnctx);
325 :
326 22 : if (!EC_POINT_mul(data->grp->group, data->my_element, NULL,
327 11 : data->grp->pwe, mask, data->bnctx)) {
328 0 : wpa_printf(MSG_INFO, "EAP-PWD (peer): element allocation "
329 : "fail");
330 0 : eap_pwd_state(data, FAILURE);
331 0 : goto fin;
332 : }
333 :
334 11 : if (!EC_POINT_invert(data->grp->group, data->my_element, data->bnctx))
335 : {
336 0 : wpa_printf(MSG_INFO, "EAP-PWD (peer): element inversion fail");
337 0 : goto fin;
338 : }
339 11 : BN_free(mask);
340 :
341 11 : if (((x = BN_new()) == NULL) ||
342 : ((y = BN_new()) == NULL)) {
343 0 : wpa_printf(MSG_INFO, "EAP-PWD (peer): point allocation fail");
344 0 : goto fin;
345 : }
346 :
347 : /* process the request */
348 22 : if (((data->server_scalar = BN_new()) == NULL) ||
349 22 : ((data->k = BN_new()) == NULL) ||
350 22 : ((K = EC_POINT_new(data->grp->group)) == NULL) ||
351 22 : ((point = EC_POINT_new(data->grp->group)) == NULL) ||
352 11 : ((data->server_element = EC_POINT_new(data->grp->group)) == NULL))
353 : {
354 0 : wpa_printf(MSG_INFO, "EAP-PWD (peer): peer data allocation "
355 : "fail");
356 0 : goto fin;
357 : }
358 :
359 : /* element, x then y, followed by scalar */
360 11 : ptr = (u8 *) payload;
361 11 : BN_bin2bn(ptr, BN_num_bytes(data->grp->prime), x);
362 11 : ptr += BN_num_bytes(data->grp->prime);
363 11 : BN_bin2bn(ptr, BN_num_bytes(data->grp->prime), y);
364 11 : ptr += BN_num_bytes(data->grp->prime);
365 11 : BN_bin2bn(ptr, BN_num_bytes(data->grp->order), data->server_scalar);
366 11 : if (!EC_POINT_set_affine_coordinates_GFp(data->grp->group,
367 : data->server_element, x, y,
368 : data->bnctx)) {
369 0 : wpa_printf(MSG_INFO, "EAP-PWD (peer): setting peer element "
370 : "fail");
371 0 : goto fin;
372 : }
373 :
374 : /* check to ensure server's element is not in a small sub-group */
375 11 : if (BN_cmp(cofactor, BN_value_one())) {
376 0 : if (!EC_POINT_mul(data->grp->group, point, NULL,
377 0 : data->server_element, cofactor, NULL)) {
378 0 : wpa_printf(MSG_INFO, "EAP-PWD (peer): cannot multiply "
379 : "server element by order!\n");
380 0 : goto fin;
381 : }
382 0 : if (EC_POINT_is_at_infinity(data->grp->group, point)) {
383 0 : wpa_printf(MSG_INFO, "EAP-PWD (peer): server element "
384 : "is at infinity!\n");
385 0 : goto fin;
386 : }
387 : }
388 :
389 : /* compute the shared key, k */
390 22 : if ((!EC_POINT_mul(data->grp->group, K, NULL, data->grp->pwe,
391 22 : data->server_scalar, data->bnctx)) ||
392 11 : (!EC_POINT_add(data->grp->group, K, K, data->server_element,
393 11 : data->bnctx)) ||
394 11 : (!EC_POINT_mul(data->grp->group, K, NULL, K, data->private_value,
395 : data->bnctx))) {
396 0 : wpa_printf(MSG_INFO, "EAP-PWD (peer): computing shared key "
397 : "fail");
398 0 : goto fin;
399 : }
400 :
401 : /* ensure that the shared key isn't in a small sub-group */
402 11 : if (BN_cmp(cofactor, BN_value_one())) {
403 0 : if (!EC_POINT_mul(data->grp->group, K, NULL, K, cofactor,
404 : NULL)) {
405 0 : wpa_printf(MSG_INFO, "EAP-PWD (peer): cannot multiply "
406 : "shared key point by order");
407 0 : goto fin;
408 : }
409 : }
410 :
411 : /*
412 : * This check is strictly speaking just for the case above where
413 : * co-factor > 1 but it was suggested that even though this is probably
414 : * never going to happen it is a simple and safe check "just to be
415 : * sure" so let's be safe.
416 : */
417 11 : if (EC_POINT_is_at_infinity(data->grp->group, K)) {
418 0 : wpa_printf(MSG_INFO, "EAP-PWD (peer): shared key point is at "
419 : "infinity!\n");
420 0 : goto fin;
421 : }
422 :
423 11 : if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group, K, data->k,
424 : NULL, data->bnctx)) {
425 0 : wpa_printf(MSG_INFO, "EAP-PWD (peer): unable to extract "
426 : "shared secret from point");
427 0 : goto fin;
428 : }
429 :
430 : /* now do the response */
431 22 : if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group,
432 11 : data->my_element, x, y,
433 : data->bnctx)) {
434 0 : wpa_printf(MSG_INFO, "EAP-PWD (peer): point assignment fail");
435 0 : goto fin;
436 : }
437 :
438 22 : if (((scalar = os_malloc(BN_num_bytes(data->grp->order))) == NULL) ||
439 11 : ((element = os_malloc(BN_num_bytes(data->grp->prime) * 2)) ==
440 : NULL)) {
441 0 : wpa_printf(MSG_INFO, "EAP-PWD (peer): data allocation fail");
442 0 : goto fin;
443 : }
444 :
445 : /*
446 : * bignums occupy as little memory as possible so one that is
447 : * sufficiently smaller than the prime or order might need pre-pending
448 : * with zeros.
449 : */
450 11 : os_memset(scalar, 0, BN_num_bytes(data->grp->order));
451 11 : os_memset(element, 0, BN_num_bytes(data->grp->prime) * 2);
452 22 : offset = BN_num_bytes(data->grp->order) -
453 11 : BN_num_bytes(data->my_scalar);
454 11 : BN_bn2bin(data->my_scalar, scalar + offset);
455 :
456 11 : offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x);
457 11 : BN_bn2bin(x, element + offset);
458 11 : offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y);
459 11 : BN_bn2bin(y, element + BN_num_bytes(data->grp->prime) + offset);
460 :
461 22 : data->outbuf = wpabuf_alloc(BN_num_bytes(data->grp->order) +
462 11 : 2 * BN_num_bytes(data->grp->prime));
463 11 : if (data->outbuf == NULL)
464 0 : goto fin;
465 :
466 : /* we send the element as (x,y) follwed by the scalar */
467 11 : wpabuf_put_data(data->outbuf, element,
468 11 : 2 * BN_num_bytes(data->grp->prime));
469 11 : wpabuf_put_data(data->outbuf, scalar, BN_num_bytes(data->grp->order));
470 :
471 : fin:
472 11 : os_free(scalar);
473 11 : os_free(element);
474 11 : BN_free(x);
475 11 : BN_free(y);
476 11 : BN_free(cofactor);
477 11 : EC_POINT_free(K);
478 11 : EC_POINT_free(point);
479 11 : if (data->outbuf == NULL)
480 0 : eap_pwd_state(data, FAILURE);
481 : else
482 11 : eap_pwd_state(data, PWD_Confirm_Req);
483 11 : }
484 :
485 :
486 : static void
487 11 : eap_pwd_perform_confirm_exchange(struct eap_sm *sm, struct eap_pwd_data *data,
488 : struct eap_method_ret *ret,
489 : const struct wpabuf *reqData,
490 : const u8 *payload, size_t payload_len)
491 : {
492 11 : BIGNUM *x = NULL, *y = NULL;
493 : struct crypto_hash *hash;
494 : u32 cs;
495 : u16 grp;
496 11 : u8 conf[SHA256_MAC_LEN], *cruft = NULL, *ptr;
497 : int offset;
498 :
499 : /*
500 : * first build up the ciphersuite which is group | random_function |
501 : * prf
502 : */
503 11 : grp = htons(data->group_num);
504 11 : ptr = (u8 *) &cs;
505 11 : os_memcpy(ptr, &grp, sizeof(u16));
506 11 : ptr += sizeof(u16);
507 11 : *ptr = EAP_PWD_DEFAULT_RAND_FUNC;
508 11 : ptr += sizeof(u8);
509 11 : *ptr = EAP_PWD_DEFAULT_PRF;
510 :
511 : /* each component of the cruft will be at most as big as the prime */
512 11 : if (((cruft = os_malloc(BN_num_bytes(data->grp->prime))) == NULL) ||
513 11 : ((x = BN_new()) == NULL) || ((y = BN_new()) == NULL)) {
514 0 : wpa_printf(MSG_INFO, "EAP-PWD (server): confirm allocation "
515 : "fail");
516 0 : goto fin;
517 : }
518 :
519 : /*
520 : * server's commit is H(k | server_element | server_scalar |
521 : * peer_element | peer_scalar | ciphersuite)
522 : */
523 11 : hash = eap_pwd_h_init();
524 11 : if (hash == NULL)
525 0 : goto fin;
526 :
527 : /*
528 : * zero the memory each time because this is mod prime math and some
529 : * value may start with a few zeros and the previous one did not.
530 : */
531 11 : os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
532 11 : offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(data->k);
533 11 : BN_bn2bin(data->k, cruft + offset);
534 11 : eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
535 :
536 : /* server element: x, y */
537 22 : if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group,
538 11 : data->server_element, x, y,
539 : data->bnctx)) {
540 0 : wpa_printf(MSG_INFO, "EAP-PWD (server): confirm point "
541 : "assignment fail");
542 0 : goto fin;
543 : }
544 11 : os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
545 11 : offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x);
546 11 : BN_bn2bin(x, cruft + offset);
547 11 : eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
548 11 : os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
549 11 : offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y);
550 11 : BN_bn2bin(y, cruft + offset);
551 11 : eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
552 :
553 : /* server scalar */
554 11 : os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
555 22 : offset = BN_num_bytes(data->grp->order) -
556 11 : BN_num_bytes(data->server_scalar);
557 11 : BN_bn2bin(data->server_scalar, cruft + offset);
558 11 : eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->order));
559 :
560 : /* my element: x, y */
561 22 : if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group,
562 11 : data->my_element, x, y,
563 : data->bnctx)) {
564 0 : wpa_printf(MSG_INFO, "EAP-PWD (server): confirm point "
565 : "assignment fail");
566 0 : goto fin;
567 : }
568 :
569 11 : os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
570 11 : offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x);
571 11 : BN_bn2bin(x, cruft + offset);
572 11 : eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
573 11 : os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
574 11 : offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y);
575 11 : BN_bn2bin(y, cruft + offset);
576 11 : eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
577 :
578 : /* my scalar */
579 11 : os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
580 22 : offset = BN_num_bytes(data->grp->order) -
581 11 : BN_num_bytes(data->my_scalar);
582 11 : BN_bn2bin(data->my_scalar, cruft + offset);
583 11 : eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->order));
584 :
585 : /* the ciphersuite */
586 11 : eap_pwd_h_update(hash, (u8 *) &cs, sizeof(u32));
587 :
588 : /* random function fin */
589 11 : eap_pwd_h_final(hash, conf);
590 :
591 11 : ptr = (u8 *) payload;
592 11 : if (os_memcmp(conf, ptr, SHA256_MAC_LEN)) {
593 1 : wpa_printf(MSG_INFO, "EAP-PWD (peer): confirm did not verify");
594 1 : goto fin;
595 : }
596 :
597 10 : wpa_printf(MSG_DEBUG, "EAP-pwd (peer): confirm verified");
598 :
599 : /*
600 : * compute confirm:
601 : * H(k | peer_element | peer_scalar | server_element | server_scalar |
602 : * ciphersuite)
603 : */
604 10 : hash = eap_pwd_h_init();
605 10 : if (hash == NULL)
606 0 : goto fin;
607 :
608 : /* k */
609 10 : os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
610 10 : offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(data->k);
611 10 : BN_bn2bin(data->k, cruft + offset);
612 10 : eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
613 :
614 : /* my element */
615 20 : if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group,
616 10 : data->my_element, x, y,
617 : data->bnctx)) {
618 0 : wpa_printf(MSG_INFO, "EAP-PWD (peer): confirm point "
619 : "assignment fail");
620 0 : goto fin;
621 : }
622 10 : os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
623 10 : offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x);
624 10 : BN_bn2bin(x, cruft + offset);
625 10 : eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
626 10 : os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
627 10 : offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y);
628 10 : BN_bn2bin(y, cruft + offset);
629 10 : eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
630 :
631 : /* my scalar */
632 10 : os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
633 20 : offset = BN_num_bytes(data->grp->order) -
634 10 : BN_num_bytes(data->my_scalar);
635 10 : BN_bn2bin(data->my_scalar, cruft + offset);
636 10 : eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->order));
637 :
638 : /* server element: x, y */
639 20 : if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group,
640 10 : data->server_element, x, y,
641 : data->bnctx)) {
642 0 : wpa_printf(MSG_INFO, "EAP-PWD (peer): confirm point "
643 : "assignment fail");
644 0 : goto fin;
645 : }
646 10 : os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
647 10 : offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x);
648 10 : BN_bn2bin(x, cruft + offset);
649 10 : eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
650 10 : os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
651 10 : offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y);
652 10 : BN_bn2bin(y, cruft + offset);
653 10 : eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
654 :
655 : /* server scalar */
656 10 : os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
657 20 : offset = BN_num_bytes(data->grp->order) -
658 10 : BN_num_bytes(data->server_scalar);
659 10 : BN_bn2bin(data->server_scalar, cruft + offset);
660 10 : eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->order));
661 :
662 : /* the ciphersuite */
663 10 : eap_pwd_h_update(hash, (u8 *) &cs, sizeof(u32));
664 :
665 : /* all done */
666 10 : eap_pwd_h_final(hash, conf);
667 :
668 10 : if (compute_keys(data->grp, data->bnctx, data->k,
669 : data->my_scalar, data->server_scalar, conf, ptr,
670 10 : &cs, data->msk, data->emsk, data->session_id) < 0) {
671 0 : wpa_printf(MSG_INFO, "EAP-PWD (peer): unable to compute MSK | "
672 : "EMSK");
673 0 : goto fin;
674 : }
675 :
676 10 : data->outbuf = wpabuf_alloc(SHA256_MAC_LEN);
677 10 : if (data->outbuf == NULL)
678 0 : goto fin;
679 :
680 10 : wpabuf_put_data(data->outbuf, conf, SHA256_MAC_LEN);
681 :
682 : fin:
683 11 : os_free(cruft);
684 11 : BN_free(x);
685 11 : BN_free(y);
686 11 : if (data->outbuf == NULL) {
687 1 : ret->methodState = METHOD_DONE;
688 1 : ret->decision = DECISION_FAIL;
689 1 : eap_pwd_state(data, FAILURE);
690 : } else {
691 10 : eap_pwd_state(data, SUCCESS_ON_FRAG_COMPLETION);
692 : }
693 11 : }
694 :
695 :
696 : static struct wpabuf *
697 46 : eap_pwd_process(struct eap_sm *sm, void *priv, struct eap_method_ret *ret,
698 : const struct wpabuf *reqData)
699 : {
700 46 : struct eap_pwd_data *data = priv;
701 46 : struct wpabuf *resp = NULL;
702 : const u8 *pos, *buf;
703 : size_t len;
704 46 : u16 tot_len = 0;
705 : u8 lm_exch;
706 :
707 46 : pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PWD, reqData, &len);
708 46 : if ((pos == NULL) || (len < 1)) {
709 0 : wpa_printf(MSG_DEBUG, "EAP-pwd: Got a frame but pos is %s and "
710 : "len is %d",
711 : pos == NULL ? "NULL" : "not NULL", (int) len);
712 0 : ret->ignore = TRUE;
713 0 : return NULL;
714 : }
715 :
716 46 : ret->ignore = FALSE;
717 46 : ret->methodState = METHOD_MAY_CONT;
718 46 : ret->decision = DECISION_FAIL;
719 46 : ret->allowNotifications = FALSE;
720 :
721 46 : lm_exch = *pos;
722 46 : pos++; /* skip over the bits and the exch */
723 46 : len--;
724 :
725 : /*
726 : * we're fragmenting so send out the next fragment
727 : */
728 46 : if (data->out_frag_pos) {
729 : /*
730 : * this should be an ACK
731 : */
732 10 : if (len)
733 0 : wpa_printf(MSG_INFO, "Bad Response! Fragmenting but "
734 : "not an ACK");
735 :
736 10 : wpa_printf(MSG_DEBUG, "EAP-pwd: Got an ACK for a fragment");
737 : /*
738 : * check if there are going to be more fragments
739 : */
740 10 : len = wpabuf_len(data->outbuf) - data->out_frag_pos;
741 10 : if ((len + EAP_PWD_HDR_SIZE) > data->mtu) {
742 5 : len = data->mtu - EAP_PWD_HDR_SIZE;
743 5 : EAP_PWD_SET_MORE_BIT(lm_exch);
744 : }
745 10 : resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD,
746 : EAP_PWD_HDR_SIZE + len,
747 10 : EAP_CODE_RESPONSE, eap_get_id(reqData));
748 10 : if (resp == NULL) {
749 0 : wpa_printf(MSG_INFO, "Unable to allocate memory for "
750 : "next fragment!");
751 0 : return NULL;
752 : }
753 10 : wpabuf_put_u8(resp, lm_exch);
754 10 : buf = wpabuf_head_u8(data->outbuf);
755 10 : wpabuf_put_data(resp, buf + data->out_frag_pos, len);
756 10 : data->out_frag_pos += len;
757 : /*
758 : * this is the last fragment so get rid of the out buffer
759 : */
760 10 : if (data->out_frag_pos >= wpabuf_len(data->outbuf)) {
761 5 : wpabuf_free(data->outbuf);
762 5 : data->outbuf = NULL;
763 5 : data->out_frag_pos = 0;
764 : }
765 20 : wpa_printf(MSG_DEBUG, "EAP-pwd: Send %s fragment of %d bytes",
766 10 : data->out_frag_pos == 0 ? "last" : "next",
767 : (int) len);
768 10 : if (data->state == SUCCESS_ON_FRAG_COMPLETION) {
769 1 : ret->methodState = METHOD_DONE;
770 1 : ret->decision = DECISION_UNCOND_SUCC;
771 1 : eap_pwd_state(data, SUCCESS);
772 : }
773 10 : return resp;
774 : }
775 :
776 : /*
777 : * see if this is a fragment that needs buffering
778 : *
779 : * if it's the first fragment there'll be a length field
780 : */
781 36 : if (EAP_PWD_GET_LENGTH_BIT(lm_exch)) {
782 1 : tot_len = WPA_GET_BE16(pos);
783 1 : wpa_printf(MSG_DEBUG, "EAP-pwd: Incoming fragments whose "
784 : "total length = %d", tot_len);
785 1 : data->inbuf = wpabuf_alloc(tot_len);
786 1 : if (data->inbuf == NULL) {
787 0 : wpa_printf(MSG_INFO, "Out of memory to buffer "
788 : "fragments!");
789 0 : return NULL;
790 : }
791 1 : pos += sizeof(u16);
792 1 : len -= sizeof(u16);
793 : }
794 : /*
795 : * buffer and ACK the fragment
796 : */
797 36 : if (EAP_PWD_GET_MORE_BIT(lm_exch)) {
798 2 : data->in_frag_pos += len;
799 2 : if (data->in_frag_pos > wpabuf_size(data->inbuf)) {
800 0 : wpa_printf(MSG_INFO, "EAP-pwd: Buffer overflow attack "
801 : "detected (%d vs. %d)!",
802 0 : (int) data->in_frag_pos,
803 0 : (int) wpabuf_len(data->inbuf));
804 0 : wpabuf_free(data->inbuf);
805 0 : data->inbuf = NULL;
806 0 : data->in_frag_pos = 0;
807 0 : return NULL;
808 : }
809 2 : wpabuf_put_data(data->inbuf, pos, len);
810 :
811 2 : resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD,
812 : EAP_PWD_HDR_SIZE,
813 2 : EAP_CODE_RESPONSE, eap_get_id(reqData));
814 2 : if (resp != NULL)
815 2 : wpabuf_put_u8(resp, (EAP_PWD_GET_EXCHANGE(lm_exch)));
816 2 : wpa_printf(MSG_DEBUG, "EAP-pwd: ACKing a %d byte fragment",
817 : (int) len);
818 2 : return resp;
819 : }
820 : /*
821 : * we're buffering and this is the last fragment
822 : */
823 34 : if (data->in_frag_pos) {
824 1 : wpabuf_put_data(data->inbuf, pos, len);
825 1 : wpa_printf(MSG_DEBUG, "EAP-pwd: Last fragment, %d bytes",
826 : (int) len);
827 1 : data->in_frag_pos += len;
828 1 : pos = wpabuf_head_u8(data->inbuf);
829 1 : len = data->in_frag_pos;
830 : }
831 34 : wpa_printf(MSG_DEBUG, "EAP-pwd: processing frame: exch %d, len %d",
832 : EAP_PWD_GET_EXCHANGE(lm_exch), (int) len);
833 :
834 34 : switch (EAP_PWD_GET_EXCHANGE(lm_exch)) {
835 : case EAP_PWD_OPCODE_ID_EXCH:
836 12 : eap_pwd_perform_id_exchange(sm, data, ret, reqData,
837 : pos, len);
838 12 : break;
839 : case EAP_PWD_OPCODE_COMMIT_EXCH:
840 11 : eap_pwd_perform_commit_exchange(sm, data, ret, reqData,
841 : pos, len);
842 11 : break;
843 : case EAP_PWD_OPCODE_CONFIRM_EXCH:
844 11 : eap_pwd_perform_confirm_exchange(sm, data, ret, reqData,
845 : pos, len);
846 11 : break;
847 : default:
848 0 : wpa_printf(MSG_INFO, "EAP-pwd: Ignoring message with unknown "
849 : "opcode %d", lm_exch);
850 0 : break;
851 : }
852 : /*
853 : * if we buffered the just processed input now's the time to free it
854 : */
855 34 : if (data->in_frag_pos) {
856 1 : wpabuf_free(data->inbuf);
857 1 : data->inbuf = NULL;
858 1 : data->in_frag_pos = 0;
859 : }
860 :
861 34 : if (data->outbuf == NULL) {
862 2 : ret->methodState = METHOD_DONE;
863 2 : ret->decision = DECISION_FAIL;
864 2 : return NULL; /* generic failure */
865 : }
866 :
867 : /*
868 : * we have output! Do we need to fragment it?
869 : */
870 32 : len = wpabuf_len(data->outbuf);
871 32 : if ((len + EAP_PWD_HDR_SIZE) > data->mtu) {
872 5 : resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD, data->mtu,
873 5 : EAP_CODE_RESPONSE, eap_get_id(reqData));
874 : /*
875 : * if so it's the first so include a length field
876 : */
877 5 : EAP_PWD_SET_LENGTH_BIT(lm_exch);
878 5 : EAP_PWD_SET_MORE_BIT(lm_exch);
879 5 : tot_len = len;
880 : /*
881 : * keep the packet at the MTU
882 : */
883 5 : len = data->mtu - EAP_PWD_HDR_SIZE - sizeof(u16);
884 5 : wpa_printf(MSG_DEBUG, "EAP-pwd: Fragmenting output, total "
885 : "length = %d", tot_len);
886 : } else {
887 27 : resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD,
888 : EAP_PWD_HDR_SIZE + len,
889 27 : EAP_CODE_RESPONSE, eap_get_id(reqData));
890 : }
891 32 : if (resp == NULL)
892 0 : return NULL;
893 :
894 32 : wpabuf_put_u8(resp, lm_exch);
895 32 : if (EAP_PWD_GET_LENGTH_BIT(lm_exch)) {
896 5 : wpabuf_put_be16(resp, tot_len);
897 5 : data->out_frag_pos += len;
898 : }
899 32 : buf = wpabuf_head_u8(data->outbuf);
900 32 : wpabuf_put_data(resp, buf, len);
901 : /*
902 : * if we're not fragmenting then there's no need to carry this around
903 : */
904 32 : if (data->out_frag_pos == 0) {
905 27 : wpabuf_free(data->outbuf);
906 27 : data->outbuf = NULL;
907 27 : data->out_frag_pos = 0;
908 27 : if (data->state == SUCCESS_ON_FRAG_COMPLETION) {
909 9 : ret->methodState = METHOD_DONE;
910 9 : ret->decision = DECISION_UNCOND_SUCC;
911 9 : eap_pwd_state(data, SUCCESS);
912 : }
913 : }
914 :
915 32 : return resp;
916 : }
917 :
918 :
919 46 : static Boolean eap_pwd_key_available(struct eap_sm *sm, void *priv)
920 : {
921 46 : struct eap_pwd_data *data = priv;
922 46 : return data->state == SUCCESS;
923 : }
924 :
925 :
926 0 : static u8 * eap_pwd_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
927 : {
928 0 : struct eap_pwd_data *data = priv;
929 : u8 *key;
930 :
931 0 : if (data->state != SUCCESS)
932 0 : return NULL;
933 :
934 0 : if ((key = os_malloc(EAP_EMSK_LEN)) == NULL)
935 0 : return NULL;
936 :
937 0 : os_memcpy(key, data->emsk, EAP_EMSK_LEN);
938 0 : *len = EAP_EMSK_LEN;
939 :
940 0 : return key;
941 : }
942 :
943 :
944 4 : int eap_peer_pwd_register(void)
945 : {
946 : struct eap_method *eap;
947 : int ret;
948 :
949 4 : EVP_add_digest(EVP_sha256());
950 4 : eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
951 : EAP_VENDOR_IETF, EAP_TYPE_PWD, "PWD");
952 4 : if (eap == NULL)
953 0 : return -1;
954 :
955 4 : eap->init = eap_pwd_init;
956 4 : eap->deinit = eap_pwd_deinit;
957 4 : eap->process = eap_pwd_process;
958 4 : eap->isKeyAvailable = eap_pwd_key_available;
959 4 : eap->getKey = eap_pwd_getkey;
960 4 : eap->getSessionId = eap_pwd_get_session_id;
961 4 : eap->get_emsk = eap_pwd_get_emsk;
962 :
963 4 : ret = eap_peer_method_register(eap);
964 4 : if (ret)
965 0 : eap_peer_method_free(eap);
966 4 : return ret;
967 : }
|
