2 * hostapd / EAP-pwd (RFC 5931) server
3 * Copyright (c) 2010, Dan Harkins <dharkins@lounge.org>
5 * This software may be distributed under the terms of the BSD license.
6 * See README for more details.
12 #include "crypto/sha256.h"
13 #include "eap_server/eap_i.h"
14 #include "eap_common/eap_pwd_common.h"
19 PWD_ID_Req, PWD_Commit_Req, PWD_Confirm_Req, SUCCESS, FAILURE
33 struct wpabuf *outbuf;
38 BIGNUM *private_value;
42 EC_POINT *peer_element;
44 u8 my_confirm[SHA256_MAC_LEN];
47 u8 emsk[EAP_EMSK_LEN];
48 u8 session_id[1 + SHA256_MAC_LEN];
54 static const char * eap_pwd_state_txt(int state)
60 return "PWD-Commit-Req";
62 return "PWD-Confirm-Req";
73 static void eap_pwd_state(struct eap_pwd_data *data, int state)
75 wpa_printf(MSG_DEBUG, "EAP-pwd: %s -> %s",
76 eap_pwd_state_txt(data->state), eap_pwd_state_txt(state));
81 static void * eap_pwd_init(struct eap_sm *sm)
83 struct eap_pwd_data *data;
85 if (sm->user == NULL || sm->user->password == NULL ||
86 sm->user->password_len == 0) {
87 wpa_printf(MSG_INFO, "EAP-PWD (server): Password is not "
92 data = os_zalloc(sizeof(*data));
96 data->group_num = sm->pwd_group;
97 wpa_printf(MSG_DEBUG, "EAP-pwd: Selected group number %d",
99 data->state = PWD_ID_Req;
101 data->id_server = (u8 *) os_strdup("server");
103 data->id_server_len = os_strlen((char *) data->id_server);
105 data->password = os_malloc(sm->user->password_len);
106 if (data->password == NULL) {
107 wpa_printf(MSG_INFO, "EAP-PWD: Memory allocation password "
109 bin_clear_free(data->id_server, data->id_server_len);
113 data->password_len = sm->user->password_len;
114 os_memcpy(data->password, sm->user->password, data->password_len);
116 data->bnctx = BN_CTX_new();
117 if (data->bnctx == NULL) {
118 wpa_printf(MSG_INFO, "EAP-PWD: bn context allocation fail");
119 bin_clear_free(data->password, data->password_len);
120 bin_clear_free(data->id_server, data->id_server_len);
125 data->in_frag_pos = data->out_frag_pos = 0;
126 data->inbuf = data->outbuf = NULL;
127 /* use default MTU from RFC 5931 if not configured otherwise */
128 data->mtu = sm->fragment_size > 0 ? sm->fragment_size : 1020;
134 static void eap_pwd_reset(struct eap_sm *sm, void *priv)
136 struct eap_pwd_data *data = priv;
138 BN_clear_free(data->private_value);
139 BN_clear_free(data->peer_scalar);
140 BN_clear_free(data->my_scalar);
141 BN_clear_free(data->k);
142 BN_CTX_free(data->bnctx);
143 EC_POINT_clear_free(data->my_element);
144 EC_POINT_clear_free(data->peer_element);
145 bin_clear_free(data->id_peer, data->id_peer_len);
146 bin_clear_free(data->id_server, data->id_server_len);
147 bin_clear_free(data->password, data->password_len);
149 EC_GROUP_free(data->grp->group);
150 EC_POINT_clear_free(data->grp->pwe);
151 BN_clear_free(data->grp->order);
152 BN_clear_free(data->grp->prime);
155 wpabuf_free(data->inbuf);
156 wpabuf_free(data->outbuf);
157 bin_clear_free(data, sizeof(*data));
161 static void eap_pwd_build_id_req(struct eap_sm *sm, struct eap_pwd_data *data,
164 wpa_printf(MSG_DEBUG, "EAP-pwd: ID/Request");
166 * if we're fragmenting then we already have an id request, just return
168 if (data->out_frag_pos)
171 data->outbuf = wpabuf_alloc(sizeof(struct eap_pwd_id) +
172 data->id_server_len);
173 if (data->outbuf == NULL) {
174 eap_pwd_state(data, FAILURE);
178 /* an lfsr is good enough to generate unpredictable tokens */
179 data->token = os_random();
180 wpabuf_put_be16(data->outbuf, data->group_num);
181 wpabuf_put_u8(data->outbuf, EAP_PWD_DEFAULT_RAND_FUNC);
182 wpabuf_put_u8(data->outbuf, EAP_PWD_DEFAULT_PRF);
183 wpabuf_put_data(data->outbuf, &data->token, sizeof(data->token));
184 wpabuf_put_u8(data->outbuf, EAP_PWD_PREP_NONE);
185 wpabuf_put_data(data->outbuf, data->id_server, data->id_server_len);
189 static void eap_pwd_build_commit_req(struct eap_sm *sm,
190 struct eap_pwd_data *data, u8 id)
192 BIGNUM *mask = NULL, *x = NULL, *y = NULL;
193 u8 *scalar = NULL, *element = NULL;
196 wpa_printf(MSG_DEBUG, "EAP-pwd: Commit/Request");
198 * if we're fragmenting then we already have an commit request, just
201 if (data->out_frag_pos)
204 if (((data->private_value = BN_new()) == NULL) ||
205 ((data->my_element = EC_POINT_new(data->grp->group)) == NULL) ||
206 ((data->my_scalar = BN_new()) == NULL) ||
207 ((mask = BN_new()) == NULL)) {
208 wpa_printf(MSG_INFO, "EAP-PWD (server): scalar allocation "
213 if (BN_rand_range(data->private_value, data->grp->order) != 1 ||
214 BN_rand_range(mask, data->grp->order) != 1 ||
215 BN_add(data->my_scalar, data->private_value, mask) != 1 ||
216 BN_mod(data->my_scalar, data->my_scalar, data->grp->order,
219 "EAP-pwd (server): unable to get randomness");
223 if (!EC_POINT_mul(data->grp->group, data->my_element, NULL,
224 data->grp->pwe, mask, data->bnctx)) {
225 wpa_printf(MSG_INFO, "EAP-PWD (server): element allocation "
227 eap_pwd_state(data, FAILURE);
231 if (!EC_POINT_invert(data->grp->group, data->my_element, data->bnctx))
233 wpa_printf(MSG_INFO, "EAP-PWD (server): element inversion "
239 if (((x = BN_new()) == NULL) ||
240 ((y = BN_new()) == NULL)) {
241 wpa_printf(MSG_INFO, "EAP-PWD (server): point allocation "
245 if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group,
246 data->my_element, x, y,
248 wpa_printf(MSG_INFO, "EAP-PWD (server): point assignment "
253 if (((scalar = os_malloc(BN_num_bytes(data->grp->order))) == NULL) ||
254 ((element = os_malloc(BN_num_bytes(data->grp->prime) * 2)) ==
256 wpa_printf(MSG_INFO, "EAP-PWD (server): data allocation fail");
261 * bignums occupy as little memory as possible so one that is
262 * sufficiently smaller than the prime or order might need pre-pending
265 os_memset(scalar, 0, BN_num_bytes(data->grp->order));
266 os_memset(element, 0, BN_num_bytes(data->grp->prime) * 2);
267 offset = BN_num_bytes(data->grp->order) -
268 BN_num_bytes(data->my_scalar);
269 BN_bn2bin(data->my_scalar, scalar + offset);
271 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x);
272 BN_bn2bin(x, element + offset);
273 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y);
274 BN_bn2bin(y, element + BN_num_bytes(data->grp->prime) + offset);
276 data->outbuf = wpabuf_alloc(2 * BN_num_bytes(data->grp->prime) +
277 BN_num_bytes(data->grp->order));
278 if (data->outbuf == NULL)
281 /* We send the element as (x,y) followed by the scalar */
282 wpabuf_put_data(data->outbuf, element,
283 2 * BN_num_bytes(data->grp->prime));
284 wpabuf_put_data(data->outbuf, scalar, BN_num_bytes(data->grp->order));
291 if (data->outbuf == NULL)
292 eap_pwd_state(data, FAILURE);
296 static void eap_pwd_build_confirm_req(struct eap_sm *sm,
297 struct eap_pwd_data *data, u8 id)
299 BIGNUM *x = NULL, *y = NULL;
300 struct crypto_hash *hash;
301 u8 conf[SHA256_MAC_LEN], *cruft = NULL, *ptr;
305 wpa_printf(MSG_DEBUG, "EAP-pwd: Confirm/Request");
307 * if we're fragmenting then we already have an confirm request, just
310 if (data->out_frag_pos)
313 /* Each component of the cruft will be at most as big as the prime */
314 if (((cruft = os_malloc(BN_num_bytes(data->grp->prime))) == NULL) ||
315 ((x = BN_new()) == NULL) || ((y = BN_new()) == NULL)) {
316 wpa_printf(MSG_INFO, "EAP-PWD (server): debug allocation "
322 * commit is H(k | server_element | server_scalar | peer_element |
323 * peer_scalar | ciphersuite)
325 hash = eap_pwd_h_init();
330 * Zero the memory each time because this is mod prime math and some
331 * value may start with a few zeros and the previous one did not.
335 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
336 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(data->k);
337 BN_bn2bin(data->k, cruft + offset);
338 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
340 /* server element: x, y */
341 if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group,
342 data->my_element, x, y,
344 wpa_printf(MSG_INFO, "EAP-PWD (server): confirm point "
349 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
350 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x);
351 BN_bn2bin(x, cruft + offset);
352 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
353 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
354 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y);
355 BN_bn2bin(y, cruft + offset);
356 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
359 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
360 offset = BN_num_bytes(data->grp->order) -
361 BN_num_bytes(data->my_scalar);
362 BN_bn2bin(data->my_scalar, cruft + offset);
363 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->order));
365 /* peer element: x, y */
366 if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group,
367 data->peer_element, x, y,
369 wpa_printf(MSG_INFO, "EAP-PWD (server): confirm point "
374 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
375 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x);
376 BN_bn2bin(x, cruft + offset);
377 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
378 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
379 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y);
380 BN_bn2bin(y, cruft + offset);
381 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
384 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
385 offset = BN_num_bytes(data->grp->order) -
386 BN_num_bytes(data->peer_scalar);
387 BN_bn2bin(data->peer_scalar, cruft + offset);
388 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->order));
391 grp = htons(data->group_num);
392 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
394 os_memcpy(ptr, &grp, sizeof(u16));
396 *ptr = EAP_PWD_DEFAULT_RAND_FUNC;
398 *ptr = EAP_PWD_DEFAULT_PRF;
400 eap_pwd_h_update(hash, cruft, ptr - cruft);
402 /* all done with the random function */
403 eap_pwd_h_final(hash, conf);
404 os_memcpy(data->my_confirm, conf, SHA256_MAC_LEN);
406 data->outbuf = wpabuf_alloc(SHA256_MAC_LEN);
407 if (data->outbuf == NULL)
410 wpabuf_put_data(data->outbuf, conf, SHA256_MAC_LEN);
413 bin_clear_free(cruft, BN_num_bytes(data->grp->prime));
416 if (data->outbuf == NULL)
417 eap_pwd_state(data, FAILURE);
421 static struct wpabuf *
422 eap_pwd_build_req(struct eap_sm *sm, void *priv, u8 id)
424 struct eap_pwd_data *data = priv;
432 * if we're buffering response fragments then just ACK
434 if (data->in_frag_pos) {
435 wpa_printf(MSG_DEBUG, "EAP-pwd: ACKing a fragment!!");
436 req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD,
437 EAP_PWD_HDR_SIZE, EAP_CODE_REQUEST, id);
439 eap_pwd_state(data, FAILURE);
442 switch (data->state) {
444 wpabuf_put_u8(req, EAP_PWD_OPCODE_ID_EXCH);
447 wpabuf_put_u8(req, EAP_PWD_OPCODE_COMMIT_EXCH);
449 case PWD_Confirm_Req:
450 wpabuf_put_u8(req, EAP_PWD_OPCODE_CONFIRM_EXCH);
453 eap_pwd_state(data, FAILURE); /* just to be sure */
461 * build the data portion of a request
463 switch (data->state) {
465 eap_pwd_build_id_req(sm, data, id);
466 lm_exch = EAP_PWD_OPCODE_ID_EXCH;
469 eap_pwd_build_commit_req(sm, data, id);
470 lm_exch = EAP_PWD_OPCODE_COMMIT_EXCH;
472 case PWD_Confirm_Req:
473 eap_pwd_build_confirm_req(sm, data, id);
474 lm_exch = EAP_PWD_OPCODE_CONFIRM_EXCH;
477 wpa_printf(MSG_INFO, "EAP-pwd: Unknown state %d in build_req",
479 eap_pwd_state(data, FAILURE);
480 lm_exch = 0; /* hush now, sweet compiler */
484 if (data->state == FAILURE)
488 * determine whether that data needs to be fragmented
490 len = wpabuf_len(data->outbuf) - data->out_frag_pos;
491 if ((len + EAP_PWD_HDR_SIZE) > data->mtu) {
492 len = data->mtu - EAP_PWD_HDR_SIZE;
493 EAP_PWD_SET_MORE_BIT(lm_exch);
495 * if this is the first fragment, need to set the M bit
496 * and add the total length to the eap_pwd_hdr
498 if (data->out_frag_pos == 0) {
499 EAP_PWD_SET_LENGTH_BIT(lm_exch);
500 totlen = wpabuf_len(data->outbuf) +
501 EAP_PWD_HDR_SIZE + sizeof(u16);
503 wpa_printf(MSG_DEBUG, "EAP-pwd: Fragmenting output, "
504 "total length = %d", totlen);
506 wpa_printf(MSG_DEBUG, "EAP-pwd: Send a %d byte fragment",
511 * alloc an eap request and populate it with the data
513 req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD,
514 EAP_PWD_HDR_SIZE + len +
515 (totlen ? sizeof(u16) : 0),
516 EAP_CODE_REQUEST, id);
518 eap_pwd_state(data, FAILURE);
522 wpabuf_put_u8(req, lm_exch);
523 if (EAP_PWD_GET_LENGTH_BIT(lm_exch))
524 wpabuf_put_be16(req, totlen);
526 buf = wpabuf_head_u8(data->outbuf);
527 wpabuf_put_data(req, buf + data->out_frag_pos, len);
528 data->out_frag_pos += len;
530 * either not fragged or last fragment, either way free up the data
532 if (data->out_frag_pos >= wpabuf_len(data->outbuf)) {
533 wpabuf_free(data->outbuf);
535 data->out_frag_pos = 0;
542 static Boolean eap_pwd_check(struct eap_sm *sm, void *priv,
543 struct wpabuf *respData)
545 struct eap_pwd_data *data = priv;
549 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PWD, respData, &len);
550 if (pos == NULL || len < 1) {
551 wpa_printf(MSG_INFO, "EAP-pwd: Invalid frame");
555 wpa_printf(MSG_DEBUG, "EAP-pwd: Received frame: exch = %d, len = %d",
556 EAP_PWD_GET_EXCHANGE(*pos), (int) len);
558 if (data->state == PWD_ID_Req &&
559 ((EAP_PWD_GET_EXCHANGE(*pos)) == EAP_PWD_OPCODE_ID_EXCH))
562 if (data->state == PWD_Commit_Req &&
563 ((EAP_PWD_GET_EXCHANGE(*pos)) == EAP_PWD_OPCODE_COMMIT_EXCH))
566 if (data->state == PWD_Confirm_Req &&
567 ((EAP_PWD_GET_EXCHANGE(*pos)) == EAP_PWD_OPCODE_CONFIRM_EXCH))
570 wpa_printf(MSG_INFO, "EAP-pwd: Unexpected opcode=%d in state=%d",
577 static void eap_pwd_process_id_resp(struct eap_sm *sm,
578 struct eap_pwd_data *data,
579 const u8 *payload, size_t payload_len)
581 struct eap_pwd_id *id;
583 if (payload_len < sizeof(struct eap_pwd_id)) {
584 wpa_printf(MSG_INFO, "EAP-pwd: Invalid ID response");
588 id = (struct eap_pwd_id *) payload;
589 if ((data->group_num != be_to_host16(id->group_num)) ||
590 (id->random_function != EAP_PWD_DEFAULT_RAND_FUNC) ||
591 (os_memcmp(id->token, (u8 *)&data->token, sizeof(data->token))) ||
592 (id->prf != EAP_PWD_DEFAULT_PRF)) {
593 wpa_printf(MSG_INFO, "EAP-pwd: peer changed parameters");
594 eap_pwd_state(data, FAILURE);
597 data->id_peer = os_malloc(payload_len - sizeof(struct eap_pwd_id));
598 if (data->id_peer == NULL) {
599 wpa_printf(MSG_INFO, "EAP-PWD: memory allocation id fail");
602 data->id_peer_len = payload_len - sizeof(struct eap_pwd_id);
603 os_memcpy(data->id_peer, id->identity, data->id_peer_len);
604 wpa_hexdump_ascii(MSG_DEBUG, "EAP-PWD (server): peer sent id of",
605 data->id_peer, data->id_peer_len);
607 data->grp = os_zalloc(sizeof(EAP_PWD_group));
608 if (data->grp == NULL) {
609 wpa_printf(MSG_INFO, "EAP-PWD: failed to allocate memory for "
613 if (compute_password_element(data->grp, data->group_num,
614 data->password, data->password_len,
615 data->id_server, data->id_server_len,
616 data->id_peer, data->id_peer_len,
617 (u8 *) &data->token)) {
618 wpa_printf(MSG_INFO, "EAP-PWD (server): unable to compute "
622 wpa_printf(MSG_DEBUG, "EAP-PWD (server): computed %d bit PWE...",
623 BN_num_bits(data->grp->prime));
625 eap_pwd_state(data, PWD_Commit_Req);
630 eap_pwd_process_commit_resp(struct eap_sm *sm, struct eap_pwd_data *data,
631 const u8 *payload, size_t payload_len)
634 BIGNUM *x = NULL, *y = NULL, *cofactor = NULL;
635 EC_POINT *K = NULL, *point = NULL;
638 wpa_printf(MSG_DEBUG, "EAP-pwd: Received commit response");
640 if (((data->peer_scalar = BN_new()) == NULL) ||
641 ((data->k = BN_new()) == NULL) ||
642 ((cofactor = BN_new()) == NULL) ||
643 ((x = BN_new()) == NULL) ||
644 ((y = BN_new()) == NULL) ||
645 ((point = EC_POINT_new(data->grp->group)) == NULL) ||
646 ((K = EC_POINT_new(data->grp->group)) == NULL) ||
647 ((data->peer_element = EC_POINT_new(data->grp->group)) == NULL)) {
648 wpa_printf(MSG_INFO, "EAP-PWD (server): peer data allocation "
653 if (!EC_GROUP_get_cofactor(data->grp->group, cofactor, NULL)) {
654 wpa_printf(MSG_INFO, "EAP-PWD (server): unable to get "
655 "cofactor for curve");
659 /* element, x then y, followed by scalar */
660 ptr = (u8 *) payload;
661 BN_bin2bn(ptr, BN_num_bytes(data->grp->prime), x);
662 ptr += BN_num_bytes(data->grp->prime);
663 BN_bin2bn(ptr, BN_num_bytes(data->grp->prime), y);
664 ptr += BN_num_bytes(data->grp->prime);
665 BN_bin2bn(ptr, BN_num_bytes(data->grp->order), data->peer_scalar);
666 if (!EC_POINT_set_affine_coordinates_GFp(data->grp->group,
667 data->peer_element, x, y,
669 wpa_printf(MSG_INFO, "EAP-PWD (server): setting peer element "
674 /* check to ensure peer's element is not in a small sub-group */
675 if (BN_cmp(cofactor, BN_value_one())) {
676 if (!EC_POINT_mul(data->grp->group, point, NULL,
677 data->peer_element, cofactor, NULL)) {
678 wpa_printf(MSG_INFO, "EAP-PWD (server): cannot "
679 "multiply peer element by order");
682 if (EC_POINT_is_at_infinity(data->grp->group, point)) {
683 wpa_printf(MSG_INFO, "EAP-PWD (server): peer element "
684 "is at infinity!\n");
689 /* compute the shared key, k */
690 if ((!EC_POINT_mul(data->grp->group, K, NULL, data->grp->pwe,
691 data->peer_scalar, data->bnctx)) ||
692 (!EC_POINT_add(data->grp->group, K, K, data->peer_element,
694 (!EC_POINT_mul(data->grp->group, K, NULL, K, data->private_value,
696 wpa_printf(MSG_INFO, "EAP-PWD (server): computing shared key "
701 /* ensure that the shared key isn't in a small sub-group */
702 if (BN_cmp(cofactor, BN_value_one())) {
703 if (!EC_POINT_mul(data->grp->group, K, NULL, K, cofactor,
705 wpa_printf(MSG_INFO, "EAP-PWD (server): cannot "
706 "multiply shared key point by order!\n");
712 * This check is strictly speaking just for the case above where
713 * co-factor > 1 but it was suggested that even though this is probably
714 * never going to happen it is a simple and safe check "just to be
715 * sure" so let's be safe.
717 if (EC_POINT_is_at_infinity(data->grp->group, K)) {
718 wpa_printf(MSG_INFO, "EAP-PWD (server): shared key point is "
722 if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group, K, data->k,
723 NULL, data->bnctx)) {
724 wpa_printf(MSG_INFO, "EAP-PWD (server): unable to extract "
725 "shared secret from secret point");
731 EC_POINT_clear_free(K);
732 EC_POINT_clear_free(point);
733 BN_clear_free(cofactor);
738 eap_pwd_state(data, PWD_Confirm_Req);
740 eap_pwd_state(data, FAILURE);
745 eap_pwd_process_confirm_resp(struct eap_sm *sm, struct eap_pwd_data *data,
746 const u8 *payload, size_t payload_len)
748 BIGNUM *x = NULL, *y = NULL;
749 struct crypto_hash *hash;
752 u8 conf[SHA256_MAC_LEN], *cruft = NULL, *ptr;
755 /* build up the ciphersuite: group | random_function | prf */
756 grp = htons(data->group_num);
758 os_memcpy(ptr, &grp, sizeof(u16));
760 *ptr = EAP_PWD_DEFAULT_RAND_FUNC;
762 *ptr = EAP_PWD_DEFAULT_PRF;
764 /* each component of the cruft will be at most as big as the prime */
765 if (((cruft = os_malloc(BN_num_bytes(data->grp->prime))) == NULL) ||
766 ((x = BN_new()) == NULL) || ((y = BN_new()) == NULL)) {
767 wpa_printf(MSG_INFO, "EAP-PWD (peer): allocation fail");
772 * commit is H(k | peer_element | peer_scalar | server_element |
773 * server_scalar | ciphersuite)
775 hash = eap_pwd_h_init();
780 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
781 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(data->k);
782 BN_bn2bin(data->k, cruft + offset);
783 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
785 /* peer element: x, y */
786 if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group,
787 data->peer_element, x, y,
789 wpa_printf(MSG_INFO, "EAP-PWD (server): confirm point "
793 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
794 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x);
795 BN_bn2bin(x, cruft + offset);
796 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
797 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
798 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y);
799 BN_bn2bin(y, cruft + offset);
800 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
803 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
804 offset = BN_num_bytes(data->grp->order) -
805 BN_num_bytes(data->peer_scalar);
806 BN_bn2bin(data->peer_scalar, cruft + offset);
807 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->order));
809 /* server element: x, y */
810 if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group,
811 data->my_element, x, y,
813 wpa_printf(MSG_INFO, "EAP-PWD (server): confirm point "
818 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
819 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x);
820 BN_bn2bin(x, cruft + offset);
821 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
822 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
823 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y);
824 BN_bn2bin(y, cruft + offset);
825 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
828 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
829 offset = BN_num_bytes(data->grp->order) -
830 BN_num_bytes(data->my_scalar);
831 BN_bn2bin(data->my_scalar, cruft + offset);
832 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->order));
835 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
836 eap_pwd_h_update(hash, (u8 *) &cs, sizeof(u32));
839 eap_pwd_h_final(hash, conf);
841 ptr = (u8 *) payload;
842 if (os_memcmp_const(conf, ptr, SHA256_MAC_LEN)) {
843 wpa_printf(MSG_INFO, "EAP-PWD (server): confirm did not "
848 wpa_printf(MSG_DEBUG, "EAP-pwd (server): confirm verified");
849 if (compute_keys(data->grp, data->bnctx, data->k,
850 data->peer_scalar, data->my_scalar, conf,
851 data->my_confirm, &cs, data->msk, data->emsk,
852 data->session_id) < 0)
853 eap_pwd_state(data, FAILURE);
855 eap_pwd_state(data, SUCCESS);
858 bin_clear_free(cruft, BN_num_bytes(data->grp->prime));
864 static void eap_pwd_process(struct eap_sm *sm, void *priv,
865 struct wpabuf *respData)
867 struct eap_pwd_data *data = priv;
873 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PWD, respData, &len);
874 if ((pos == NULL) || (len < 1)) {
875 wpa_printf(MSG_INFO, "Bad EAP header! pos %s and len = %d",
876 (pos == NULL) ? "is NULL" : "is not NULL",
882 pos++; /* skip over the bits and the exch */
886 * if we're fragmenting then this should be an ACK with no data,
887 * just return and continue fragmenting in the "build" section above
889 if (data->out_frag_pos) {
891 wpa_printf(MSG_INFO, "EAP-pwd: Bad response! "
892 "Fragmenting but not an ACK");
894 wpa_printf(MSG_DEBUG, "EAP-pwd: received ACK from "
899 * if we're receiving fragmented packets then we need to buffer...
901 * the first fragment has a total length
903 if (EAP_PWD_GET_LENGTH_BIT(lm_exch)) {
904 tot_len = WPA_GET_BE16(pos);
905 wpa_printf(MSG_DEBUG, "EAP-pwd: Incoming fragments, total "
906 "length = %d", tot_len);
909 data->inbuf = wpabuf_alloc(tot_len);
910 if (data->inbuf == NULL) {
911 wpa_printf(MSG_INFO, "EAP-pwd: Out of memory to "
912 "buffer fragments!");
919 * the first and all intermediate fragments have the M bit set
921 if (EAP_PWD_GET_MORE_BIT(lm_exch)) {
922 if ((data->in_frag_pos + len) > wpabuf_size(data->inbuf)) {
923 wpa_printf(MSG_DEBUG, "EAP-pwd: Buffer overflow "
924 "attack detected! (%d+%d > %d)",
925 (int) data->in_frag_pos, (int) len,
926 (int) wpabuf_size(data->inbuf));
927 eap_pwd_state(data, FAILURE);
930 wpabuf_put_data(data->inbuf, pos, len);
931 data->in_frag_pos += len;
932 wpa_printf(MSG_DEBUG, "EAP-pwd: Got a %d byte fragment",
937 * last fragment won't have the M bit set (but we're obviously
938 * buffering fragments so that's how we know it's the last)
940 if (data->in_frag_pos) {
941 wpabuf_put_data(data->inbuf, pos, len);
942 data->in_frag_pos += len;
943 pos = wpabuf_head_u8(data->inbuf);
944 len = data->in_frag_pos;
945 wpa_printf(MSG_DEBUG, "EAP-pwd: Last fragment, %d bytes",
948 switch (EAP_PWD_GET_EXCHANGE(lm_exch)) {
949 case EAP_PWD_OPCODE_ID_EXCH:
950 eap_pwd_process_id_resp(sm, data, pos, len);
952 case EAP_PWD_OPCODE_COMMIT_EXCH:
953 eap_pwd_process_commit_resp(sm, data, pos, len);
955 case EAP_PWD_OPCODE_CONFIRM_EXCH:
956 eap_pwd_process_confirm_resp(sm, data, pos, len);
960 * if we had been buffering fragments, here's a great place
963 if (data->in_frag_pos) {
964 wpabuf_free(data->inbuf);
966 data->in_frag_pos = 0;
971 static u8 * eap_pwd_getkey(struct eap_sm *sm, void *priv, size_t *len)
973 struct eap_pwd_data *data = priv;
976 if (data->state != SUCCESS)
979 key = os_malloc(EAP_MSK_LEN);
983 os_memcpy(key, data->msk, EAP_MSK_LEN);
990 static u8 * eap_pwd_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
992 struct eap_pwd_data *data = priv;
995 if (data->state != SUCCESS)
998 key = os_malloc(EAP_EMSK_LEN);
1002 os_memcpy(key, data->emsk, EAP_EMSK_LEN);
1003 *len = EAP_EMSK_LEN;
1009 static Boolean eap_pwd_is_success(struct eap_sm *sm, void *priv)
1011 struct eap_pwd_data *data = priv;
1012 return data->state == SUCCESS;
1016 static Boolean eap_pwd_is_done(struct eap_sm *sm, void *priv)
1018 struct eap_pwd_data *data = priv;
1019 return (data->state == SUCCESS) || (data->state == FAILURE);
1023 static u8 * eap_pwd_get_session_id(struct eap_sm *sm, void *priv, size_t *len)
1025 struct eap_pwd_data *data = priv;
1028 if (data->state != SUCCESS)
1031 id = os_malloc(1 + SHA256_MAC_LEN);
1035 os_memcpy(id, data->session_id, 1 + SHA256_MAC_LEN);
1036 *len = 1 + SHA256_MAC_LEN;
1042 int eap_server_pwd_register(void)
1044 struct eap_method *eap;
1051 (void) gettimeofday(&tp, &tz);
1052 sr ^= (tp.tv_sec ^ tp.tv_usec);
1055 eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
1056 EAP_VENDOR_IETF, EAP_TYPE_PWD,
1061 eap->init = eap_pwd_init;
1062 eap->reset = eap_pwd_reset;
1063 eap->buildReq = eap_pwd_build_req;
1064 eap->check = eap_pwd_check;
1065 eap->process = eap_pwd_process;
1066 eap->isDone = eap_pwd_is_done;
1067 eap->getKey = eap_pwd_getkey;
1068 eap->get_emsk = eap_pwd_get_emsk;
1069 eap->isSuccess = eap_pwd_is_success;
1070 eap->getSessionId = eap_pwd_get_session_id;
1072 ret = eap_server_method_register(eap);
1074 eap_server_method_free(eap);