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 "crypto/ms_funcs.h"
14 #include "eap_server/eap_i.h"
15 #include "eap_common/eap_pwd_common.h"
20 PWD_ID_Req, PWD_Commit_Req, PWD_Confirm_Req, SUCCESS, FAILURE
35 struct wpabuf *outbuf;
40 BIGNUM *private_value;
44 EC_POINT *peer_element;
46 u8 my_confirm[SHA256_MAC_LEN];
49 u8 emsk[EAP_EMSK_LEN];
50 u8 session_id[1 + SHA256_MAC_LEN];
56 static const char * eap_pwd_state_txt(int state)
62 return "PWD-Commit-Req";
64 return "PWD-Confirm-Req";
75 static void eap_pwd_state(struct eap_pwd_data *data, int state)
77 wpa_printf(MSG_DEBUG, "EAP-pwd: %s -> %s",
78 eap_pwd_state_txt(data->state), eap_pwd_state_txt(state));
83 static void * eap_pwd_init(struct eap_sm *sm)
85 struct eap_pwd_data *data;
87 if (sm->user == NULL || sm->user->password == NULL ||
88 sm->user->password_len == 0) {
89 wpa_printf(MSG_INFO, "EAP-PWD (server): Password is not "
94 data = os_zalloc(sizeof(*data));
98 data->group_num = sm->pwd_group;
99 wpa_printf(MSG_DEBUG, "EAP-pwd: Selected group number %d",
101 data->state = PWD_ID_Req;
103 data->id_server = (u8 *) os_strdup("server");
105 data->id_server_len = os_strlen((char *) data->id_server);
107 data->password = os_malloc(sm->user->password_len);
108 if (data->password == NULL) {
109 wpa_printf(MSG_INFO, "EAP-PWD: Memory allocation password "
111 bin_clear_free(data->id_server, data->id_server_len);
115 data->password_len = sm->user->password_len;
116 os_memcpy(data->password, sm->user->password, data->password_len);
117 data->password_hash = sm->user->password_hash;
119 data->bnctx = BN_CTX_new();
120 if (data->bnctx == NULL) {
121 wpa_printf(MSG_INFO, "EAP-PWD: bn context allocation fail");
122 bin_clear_free(data->password, data->password_len);
123 bin_clear_free(data->id_server, data->id_server_len);
128 data->in_frag_pos = data->out_frag_pos = 0;
129 data->inbuf = data->outbuf = NULL;
130 /* use default MTU from RFC 5931 if not configured otherwise */
131 data->mtu = sm->fragment_size > 0 ? sm->fragment_size : 1020;
137 static void eap_pwd_reset(struct eap_sm *sm, void *priv)
139 struct eap_pwd_data *data = priv;
141 BN_clear_free(data->private_value);
142 BN_clear_free(data->peer_scalar);
143 BN_clear_free(data->my_scalar);
144 BN_clear_free(data->k);
145 BN_CTX_free(data->bnctx);
146 EC_POINT_clear_free(data->my_element);
147 EC_POINT_clear_free(data->peer_element);
148 bin_clear_free(data->id_peer, data->id_peer_len);
149 bin_clear_free(data->id_server, data->id_server_len);
150 bin_clear_free(data->password, data->password_len);
152 EC_GROUP_free(data->grp->group);
153 EC_POINT_clear_free(data->grp->pwe);
154 BN_clear_free(data->grp->order);
155 BN_clear_free(data->grp->prime);
158 wpabuf_free(data->inbuf);
159 wpabuf_free(data->outbuf);
160 bin_clear_free(data, sizeof(*data));
164 static void eap_pwd_build_id_req(struct eap_sm *sm, struct eap_pwd_data *data,
167 wpa_printf(MSG_DEBUG, "EAP-pwd: ID/Request");
169 * if we're fragmenting then we already have an id request, just return
171 if (data->out_frag_pos)
174 data->outbuf = wpabuf_alloc(sizeof(struct eap_pwd_id) +
175 data->id_server_len);
176 if (data->outbuf == NULL) {
177 eap_pwd_state(data, FAILURE);
181 /* an lfsr is good enough to generate unpredictable tokens */
182 data->token = os_random();
183 wpabuf_put_be16(data->outbuf, data->group_num);
184 wpabuf_put_u8(data->outbuf, EAP_PWD_DEFAULT_RAND_FUNC);
185 wpabuf_put_u8(data->outbuf, EAP_PWD_DEFAULT_PRF);
186 wpabuf_put_data(data->outbuf, &data->token, sizeof(data->token));
187 wpabuf_put_u8(data->outbuf, data->password_hash ? EAP_PWD_PREP_MS :
189 wpabuf_put_data(data->outbuf, data->id_server, data->id_server_len);
193 static void eap_pwd_build_commit_req(struct eap_sm *sm,
194 struct eap_pwd_data *data, u8 id)
196 BIGNUM *mask = NULL, *x = NULL, *y = NULL;
197 u8 *scalar = NULL, *element = NULL;
200 wpa_printf(MSG_DEBUG, "EAP-pwd: Commit/Request");
202 * if we're fragmenting then we already have an commit request, just
205 if (data->out_frag_pos)
208 if (((data->private_value = BN_new()) == NULL) ||
209 ((data->my_element = EC_POINT_new(data->grp->group)) == NULL) ||
210 ((data->my_scalar = BN_new()) == NULL) ||
211 ((mask = BN_new()) == NULL)) {
212 wpa_printf(MSG_INFO, "EAP-PWD (server): scalar allocation "
217 if (BN_rand_range(data->private_value, data->grp->order) != 1 ||
218 BN_rand_range(mask, data->grp->order) != 1 ||
219 BN_add(data->my_scalar, data->private_value, mask) != 1 ||
220 BN_mod(data->my_scalar, data->my_scalar, data->grp->order,
223 "EAP-pwd (server): unable to get randomness");
227 if (!EC_POINT_mul(data->grp->group, data->my_element, NULL,
228 data->grp->pwe, mask, data->bnctx)) {
229 wpa_printf(MSG_INFO, "EAP-PWD (server): element allocation "
231 eap_pwd_state(data, FAILURE);
235 if (!EC_POINT_invert(data->grp->group, data->my_element, data->bnctx))
237 wpa_printf(MSG_INFO, "EAP-PWD (server): element inversion "
243 if (((x = BN_new()) == NULL) ||
244 ((y = BN_new()) == NULL)) {
245 wpa_printf(MSG_INFO, "EAP-PWD (server): point allocation "
249 if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group,
250 data->my_element, x, y,
252 wpa_printf(MSG_INFO, "EAP-PWD (server): point assignment "
257 if (((scalar = os_malloc(BN_num_bytes(data->grp->order))) == NULL) ||
258 ((element = os_malloc(BN_num_bytes(data->grp->prime) * 2)) ==
260 wpa_printf(MSG_INFO, "EAP-PWD (server): data allocation fail");
265 * bignums occupy as little memory as possible so one that is
266 * sufficiently smaller than the prime or order might need pre-pending
269 os_memset(scalar, 0, BN_num_bytes(data->grp->order));
270 os_memset(element, 0, BN_num_bytes(data->grp->prime) * 2);
271 offset = BN_num_bytes(data->grp->order) -
272 BN_num_bytes(data->my_scalar);
273 BN_bn2bin(data->my_scalar, scalar + offset);
275 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x);
276 BN_bn2bin(x, element + offset);
277 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y);
278 BN_bn2bin(y, element + BN_num_bytes(data->grp->prime) + offset);
280 data->outbuf = wpabuf_alloc(2 * BN_num_bytes(data->grp->prime) +
281 BN_num_bytes(data->grp->order));
282 if (data->outbuf == NULL)
285 /* We send the element as (x,y) followed by the scalar */
286 wpabuf_put_data(data->outbuf, element,
287 2 * BN_num_bytes(data->grp->prime));
288 wpabuf_put_data(data->outbuf, scalar, BN_num_bytes(data->grp->order));
295 if (data->outbuf == NULL)
296 eap_pwd_state(data, FAILURE);
300 static void eap_pwd_build_confirm_req(struct eap_sm *sm,
301 struct eap_pwd_data *data, u8 id)
303 BIGNUM *x = NULL, *y = NULL;
304 struct crypto_hash *hash;
305 u8 conf[SHA256_MAC_LEN], *cruft = NULL, *ptr;
309 wpa_printf(MSG_DEBUG, "EAP-pwd: Confirm/Request");
311 * if we're fragmenting then we already have an confirm request, just
314 if (data->out_frag_pos)
317 /* Each component of the cruft will be at most as big as the prime */
318 if (((cruft = os_malloc(BN_num_bytes(data->grp->prime))) == NULL) ||
319 ((x = BN_new()) == NULL) || ((y = BN_new()) == NULL)) {
320 wpa_printf(MSG_INFO, "EAP-PWD (server): debug allocation "
326 * commit is H(k | server_element | server_scalar | peer_element |
327 * peer_scalar | ciphersuite)
329 hash = eap_pwd_h_init();
334 * Zero the memory each time because this is mod prime math and some
335 * value may start with a few zeros and the previous one did not.
339 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
340 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(data->k);
341 BN_bn2bin(data->k, cruft + offset);
342 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
344 /* server element: x, y */
345 if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group,
346 data->my_element, x, y,
348 wpa_printf(MSG_INFO, "EAP-PWD (server): confirm point "
353 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
354 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x);
355 BN_bn2bin(x, cruft + offset);
356 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
357 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
358 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y);
359 BN_bn2bin(y, cruft + offset);
360 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
363 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
364 offset = BN_num_bytes(data->grp->order) -
365 BN_num_bytes(data->my_scalar);
366 BN_bn2bin(data->my_scalar, cruft + offset);
367 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->order));
369 /* peer element: x, y */
370 if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group,
371 data->peer_element, x, y,
373 wpa_printf(MSG_INFO, "EAP-PWD (server): confirm point "
378 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
379 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x);
380 BN_bn2bin(x, cruft + offset);
381 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
382 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
383 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y);
384 BN_bn2bin(y, cruft + offset);
385 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
388 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
389 offset = BN_num_bytes(data->grp->order) -
390 BN_num_bytes(data->peer_scalar);
391 BN_bn2bin(data->peer_scalar, cruft + offset);
392 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->order));
395 grp = htons(data->group_num);
396 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
398 os_memcpy(ptr, &grp, sizeof(u16));
400 *ptr = EAP_PWD_DEFAULT_RAND_FUNC;
402 *ptr = EAP_PWD_DEFAULT_PRF;
404 eap_pwd_h_update(hash, cruft, ptr - cruft);
406 /* all done with the random function */
407 eap_pwd_h_final(hash, conf);
408 os_memcpy(data->my_confirm, conf, SHA256_MAC_LEN);
410 data->outbuf = wpabuf_alloc(SHA256_MAC_LEN);
411 if (data->outbuf == NULL)
414 wpabuf_put_data(data->outbuf, conf, SHA256_MAC_LEN);
417 bin_clear_free(cruft, BN_num_bytes(data->grp->prime));
420 if (data->outbuf == NULL)
421 eap_pwd_state(data, FAILURE);
425 static struct wpabuf *
426 eap_pwd_build_req(struct eap_sm *sm, void *priv, u8 id)
428 struct eap_pwd_data *data = priv;
436 * if we're buffering response fragments then just ACK
438 if (data->in_frag_pos) {
439 wpa_printf(MSG_DEBUG, "EAP-pwd: ACKing a fragment!!");
440 req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD,
441 EAP_PWD_HDR_SIZE, EAP_CODE_REQUEST, id);
443 eap_pwd_state(data, FAILURE);
446 switch (data->state) {
448 wpabuf_put_u8(req, EAP_PWD_OPCODE_ID_EXCH);
451 wpabuf_put_u8(req, EAP_PWD_OPCODE_COMMIT_EXCH);
453 case PWD_Confirm_Req:
454 wpabuf_put_u8(req, EAP_PWD_OPCODE_CONFIRM_EXCH);
457 eap_pwd_state(data, FAILURE); /* just to be sure */
465 * build the data portion of a request
467 switch (data->state) {
469 eap_pwd_build_id_req(sm, data, id);
470 lm_exch = EAP_PWD_OPCODE_ID_EXCH;
473 eap_pwd_build_commit_req(sm, data, id);
474 lm_exch = EAP_PWD_OPCODE_COMMIT_EXCH;
476 case PWD_Confirm_Req:
477 eap_pwd_build_confirm_req(sm, data, id);
478 lm_exch = EAP_PWD_OPCODE_CONFIRM_EXCH;
481 wpa_printf(MSG_INFO, "EAP-pwd: Unknown state %d in build_req",
483 eap_pwd_state(data, FAILURE);
484 lm_exch = 0; /* hush now, sweet compiler */
488 if (data->state == FAILURE)
492 * determine whether that data needs to be fragmented
494 len = wpabuf_len(data->outbuf) - data->out_frag_pos;
495 if ((len + EAP_PWD_HDR_SIZE) > data->mtu) {
496 len = data->mtu - EAP_PWD_HDR_SIZE;
497 EAP_PWD_SET_MORE_BIT(lm_exch);
499 * if this is the first fragment, need to set the M bit
500 * and add the total length to the eap_pwd_hdr
502 if (data->out_frag_pos == 0) {
503 EAP_PWD_SET_LENGTH_BIT(lm_exch);
504 totlen = wpabuf_len(data->outbuf) +
505 EAP_PWD_HDR_SIZE + sizeof(u16);
507 wpa_printf(MSG_DEBUG, "EAP-pwd: Fragmenting output, "
508 "total length = %d", totlen);
510 wpa_printf(MSG_DEBUG, "EAP-pwd: Send a %d byte fragment",
515 * alloc an eap request and populate it with the data
517 req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD,
518 EAP_PWD_HDR_SIZE + len +
519 (totlen ? sizeof(u16) : 0),
520 EAP_CODE_REQUEST, id);
522 eap_pwd_state(data, FAILURE);
526 wpabuf_put_u8(req, lm_exch);
527 if (EAP_PWD_GET_LENGTH_BIT(lm_exch))
528 wpabuf_put_be16(req, totlen);
530 buf = wpabuf_head_u8(data->outbuf);
531 wpabuf_put_data(req, buf + data->out_frag_pos, len);
532 data->out_frag_pos += len;
534 * either not fragged or last fragment, either way free up the data
536 if (data->out_frag_pos >= wpabuf_len(data->outbuf)) {
537 wpabuf_free(data->outbuf);
539 data->out_frag_pos = 0;
546 static Boolean eap_pwd_check(struct eap_sm *sm, void *priv,
547 struct wpabuf *respData)
549 struct eap_pwd_data *data = priv;
553 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PWD, respData, &len);
554 if (pos == NULL || len < 1) {
555 wpa_printf(MSG_INFO, "EAP-pwd: Invalid frame");
559 wpa_printf(MSG_DEBUG, "EAP-pwd: Received frame: exch = %d, len = %d",
560 EAP_PWD_GET_EXCHANGE(*pos), (int) len);
562 if (data->state == PWD_ID_Req &&
563 ((EAP_PWD_GET_EXCHANGE(*pos)) == EAP_PWD_OPCODE_ID_EXCH))
566 if (data->state == PWD_Commit_Req &&
567 ((EAP_PWD_GET_EXCHANGE(*pos)) == EAP_PWD_OPCODE_COMMIT_EXCH))
570 if (data->state == PWD_Confirm_Req &&
571 ((EAP_PWD_GET_EXCHANGE(*pos)) == EAP_PWD_OPCODE_CONFIRM_EXCH))
574 wpa_printf(MSG_INFO, "EAP-pwd: Unexpected opcode=%d in state=%d",
581 static void eap_pwd_process_id_resp(struct eap_sm *sm,
582 struct eap_pwd_data *data,
583 const u8 *payload, size_t payload_len)
585 struct eap_pwd_id *id;
591 if (payload_len < sizeof(struct eap_pwd_id)) {
592 wpa_printf(MSG_INFO, "EAP-pwd: Invalid ID response");
596 id = (struct eap_pwd_id *) payload;
597 if ((data->group_num != be_to_host16(id->group_num)) ||
598 (id->random_function != EAP_PWD_DEFAULT_RAND_FUNC) ||
599 (os_memcmp(id->token, (u8 *)&data->token, sizeof(data->token))) ||
600 (id->prf != EAP_PWD_DEFAULT_PRF)) {
601 wpa_printf(MSG_INFO, "EAP-pwd: peer changed parameters");
602 eap_pwd_state(data, FAILURE);
605 data->id_peer = os_malloc(payload_len - sizeof(struct eap_pwd_id));
606 if (data->id_peer == NULL) {
607 wpa_printf(MSG_INFO, "EAP-PWD: memory allocation id fail");
610 data->id_peer_len = payload_len - sizeof(struct eap_pwd_id);
611 os_memcpy(data->id_peer, id->identity, data->id_peer_len);
612 wpa_hexdump_ascii(MSG_DEBUG, "EAP-PWD (server): peer sent id of",
613 data->id_peer, data->id_peer_len);
615 data->grp = os_zalloc(sizeof(EAP_PWD_group));
616 if (data->grp == NULL) {
617 wpa_printf(MSG_INFO, "EAP-PWD: failed to allocate memory for "
622 if (data->password_hash) {
623 res = hash_nt_password_hash(data->password, pwhashhash);
626 password = pwhashhash;
627 password_len = sizeof(pwhashhash);
629 password = data->password;
630 password_len = data->password_len;
633 res = compute_password_element(data->grp, data->group_num,
634 password, password_len,
635 data->id_server, data->id_server_len,
636 data->id_peer, data->id_peer_len,
637 (u8 *) &data->token);
638 os_memset(pwhashhash, 0, sizeof(pwhashhash));
640 wpa_printf(MSG_INFO, "EAP-PWD (server): unable to compute "
644 wpa_printf(MSG_DEBUG, "EAP-PWD (server): computed %d bit PWE...",
645 BN_num_bits(data->grp->prime));
647 eap_pwd_state(data, PWD_Commit_Req);
652 eap_pwd_process_commit_resp(struct eap_sm *sm, struct eap_pwd_data *data,
653 const u8 *payload, size_t payload_len)
656 BIGNUM *x = NULL, *y = NULL, *cofactor = NULL;
657 EC_POINT *K = NULL, *point = NULL;
659 size_t prime_len, order_len;
661 wpa_printf(MSG_DEBUG, "EAP-pwd: Received commit response");
663 prime_len = BN_num_bytes(data->grp->prime);
664 order_len = BN_num_bytes(data->grp->order);
666 if (payload_len != 2 * prime_len + order_len) {
668 "EAP-pwd: Unexpected Commit payload length %u (expected %u)",
669 (unsigned int) payload_len,
670 (unsigned int) (2 * prime_len + order_len));
674 if (((data->peer_scalar = BN_new()) == NULL) ||
675 ((data->k = BN_new()) == NULL) ||
676 ((cofactor = BN_new()) == NULL) ||
677 ((x = BN_new()) == NULL) ||
678 ((y = BN_new()) == NULL) ||
679 ((point = EC_POINT_new(data->grp->group)) == NULL) ||
680 ((K = EC_POINT_new(data->grp->group)) == NULL) ||
681 ((data->peer_element = EC_POINT_new(data->grp->group)) == NULL)) {
682 wpa_printf(MSG_INFO, "EAP-PWD (server): peer data allocation "
687 if (!EC_GROUP_get_cofactor(data->grp->group, cofactor, NULL)) {
688 wpa_printf(MSG_INFO, "EAP-PWD (server): unable to get "
689 "cofactor for curve");
693 /* element, x then y, followed by scalar */
694 ptr = (u8 *) payload;
695 BN_bin2bn(ptr, BN_num_bytes(data->grp->prime), x);
696 ptr += BN_num_bytes(data->grp->prime);
697 BN_bin2bn(ptr, BN_num_bytes(data->grp->prime), y);
698 ptr += BN_num_bytes(data->grp->prime);
699 BN_bin2bn(ptr, BN_num_bytes(data->grp->order), data->peer_scalar);
700 if (!EC_POINT_set_affine_coordinates_GFp(data->grp->group,
701 data->peer_element, x, y,
703 wpa_printf(MSG_INFO, "EAP-PWD (server): setting peer element "
708 /* check to ensure peer's element is not in a small sub-group */
709 if (BN_cmp(cofactor, BN_value_one())) {
710 if (!EC_POINT_mul(data->grp->group, point, NULL,
711 data->peer_element, cofactor, NULL)) {
712 wpa_printf(MSG_INFO, "EAP-PWD (server): cannot "
713 "multiply peer element by order");
716 if (EC_POINT_is_at_infinity(data->grp->group, point)) {
717 wpa_printf(MSG_INFO, "EAP-PWD (server): peer element "
718 "is at infinity!\n");
723 /* compute the shared key, k */
724 if ((!EC_POINT_mul(data->grp->group, K, NULL, data->grp->pwe,
725 data->peer_scalar, data->bnctx)) ||
726 (!EC_POINT_add(data->grp->group, K, K, data->peer_element,
728 (!EC_POINT_mul(data->grp->group, K, NULL, K, data->private_value,
730 wpa_printf(MSG_INFO, "EAP-PWD (server): computing shared key "
735 /* ensure that the shared key isn't in a small sub-group */
736 if (BN_cmp(cofactor, BN_value_one())) {
737 if (!EC_POINT_mul(data->grp->group, K, NULL, K, cofactor,
739 wpa_printf(MSG_INFO, "EAP-PWD (server): cannot "
740 "multiply shared key point by order!\n");
746 * This check is strictly speaking just for the case above where
747 * co-factor > 1 but it was suggested that even though this is probably
748 * never going to happen it is a simple and safe check "just to be
749 * sure" so let's be safe.
751 if (EC_POINT_is_at_infinity(data->grp->group, K)) {
752 wpa_printf(MSG_INFO, "EAP-PWD (server): shared key point is "
756 if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group, K, data->k,
757 NULL, data->bnctx)) {
758 wpa_printf(MSG_INFO, "EAP-PWD (server): unable to extract "
759 "shared secret from secret point");
765 EC_POINT_clear_free(K);
766 EC_POINT_clear_free(point);
767 BN_clear_free(cofactor);
772 eap_pwd_state(data, PWD_Confirm_Req);
774 eap_pwd_state(data, FAILURE);
779 eap_pwd_process_confirm_resp(struct eap_sm *sm, struct eap_pwd_data *data,
780 const u8 *payload, size_t payload_len)
782 BIGNUM *x = NULL, *y = NULL;
783 struct crypto_hash *hash;
786 u8 conf[SHA256_MAC_LEN], *cruft = NULL, *ptr;
789 if (payload_len != SHA256_MAC_LEN) {
791 "EAP-pwd: Unexpected Confirm payload length %u (expected %u)",
792 (unsigned int) payload_len, SHA256_MAC_LEN);
796 /* build up the ciphersuite: group | random_function | prf */
797 grp = htons(data->group_num);
799 os_memcpy(ptr, &grp, sizeof(u16));
801 *ptr = EAP_PWD_DEFAULT_RAND_FUNC;
803 *ptr = EAP_PWD_DEFAULT_PRF;
805 /* each component of the cruft will be at most as big as the prime */
806 if (((cruft = os_malloc(BN_num_bytes(data->grp->prime))) == NULL) ||
807 ((x = BN_new()) == NULL) || ((y = BN_new()) == NULL)) {
808 wpa_printf(MSG_INFO, "EAP-PWD (peer): allocation fail");
813 * commit is H(k | peer_element | peer_scalar | server_element |
814 * server_scalar | ciphersuite)
816 hash = eap_pwd_h_init();
821 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
822 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(data->k);
823 BN_bn2bin(data->k, cruft + offset);
824 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
826 /* peer element: x, y */
827 if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group,
828 data->peer_element, x, y,
830 wpa_printf(MSG_INFO, "EAP-PWD (server): confirm point "
834 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
835 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x);
836 BN_bn2bin(x, cruft + offset);
837 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
838 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
839 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y);
840 BN_bn2bin(y, cruft + offset);
841 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
844 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
845 offset = BN_num_bytes(data->grp->order) -
846 BN_num_bytes(data->peer_scalar);
847 BN_bn2bin(data->peer_scalar, cruft + offset);
848 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->order));
850 /* server element: x, y */
851 if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group,
852 data->my_element, x, y,
854 wpa_printf(MSG_INFO, "EAP-PWD (server): confirm point "
859 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
860 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x);
861 BN_bn2bin(x, cruft + offset);
862 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
863 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
864 offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y);
865 BN_bn2bin(y, cruft + offset);
866 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->prime));
869 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
870 offset = BN_num_bytes(data->grp->order) -
871 BN_num_bytes(data->my_scalar);
872 BN_bn2bin(data->my_scalar, cruft + offset);
873 eap_pwd_h_update(hash, cruft, BN_num_bytes(data->grp->order));
876 os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
877 eap_pwd_h_update(hash, (u8 *) &cs, sizeof(u32));
880 eap_pwd_h_final(hash, conf);
882 ptr = (u8 *) payload;
883 if (os_memcmp_const(conf, ptr, SHA256_MAC_LEN)) {
884 wpa_printf(MSG_INFO, "EAP-PWD (server): confirm did not "
889 wpa_printf(MSG_DEBUG, "EAP-pwd (server): confirm verified");
890 if (compute_keys(data->grp, data->bnctx, data->k,
891 data->peer_scalar, data->my_scalar, conf,
892 data->my_confirm, &cs, data->msk, data->emsk,
893 data->session_id) < 0)
894 eap_pwd_state(data, FAILURE);
896 eap_pwd_state(data, SUCCESS);
899 bin_clear_free(cruft, BN_num_bytes(data->grp->prime));
905 static void eap_pwd_process(struct eap_sm *sm, void *priv,
906 struct wpabuf *respData)
908 struct eap_pwd_data *data = priv;
914 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PWD, respData, &len);
915 if ((pos == NULL) || (len < 1)) {
916 wpa_printf(MSG_INFO, "Bad EAP header! pos %s and len = %d",
917 (pos == NULL) ? "is NULL" : "is not NULL",
923 pos++; /* skip over the bits and the exch */
927 * if we're fragmenting then this should be an ACK with no data,
928 * just return and continue fragmenting in the "build" section above
930 if (data->out_frag_pos) {
932 wpa_printf(MSG_INFO, "EAP-pwd: Bad response! "
933 "Fragmenting but not an ACK");
935 wpa_printf(MSG_DEBUG, "EAP-pwd: received ACK from "
940 * if we're receiving fragmented packets then we need to buffer...
942 * the first fragment has a total length
944 if (EAP_PWD_GET_LENGTH_BIT(lm_exch)) {
946 wpa_printf(MSG_DEBUG,
947 "EAP-pwd: Frame too short to contain Total-Length field");
950 tot_len = WPA_GET_BE16(pos);
951 wpa_printf(MSG_DEBUG, "EAP-pwd: Incoming fragments, total "
952 "length = %d", tot_len);
956 wpa_printf(MSG_DEBUG,
957 "EAP-pwd: Unexpected new fragment start when previous fragment is still in use");
960 data->inbuf = wpabuf_alloc(tot_len);
961 if (data->inbuf == NULL) {
962 wpa_printf(MSG_INFO, "EAP-pwd: Out of memory to "
963 "buffer fragments!");
966 data->in_frag_pos = 0;
971 * the first and all intermediate fragments have the M bit set
973 if (EAP_PWD_GET_MORE_BIT(lm_exch)) {
974 if ((data->in_frag_pos + len) > wpabuf_size(data->inbuf)) {
975 wpa_printf(MSG_DEBUG, "EAP-pwd: Buffer overflow "
976 "attack detected! (%d+%d > %d)",
977 (int) data->in_frag_pos, (int) len,
978 (int) wpabuf_size(data->inbuf));
979 eap_pwd_state(data, FAILURE);
982 wpabuf_put_data(data->inbuf, pos, len);
983 data->in_frag_pos += len;
984 wpa_printf(MSG_DEBUG, "EAP-pwd: Got a %d byte fragment",
989 * last fragment won't have the M bit set (but we're obviously
990 * buffering fragments so that's how we know it's the last)
992 if (data->in_frag_pos) {
993 wpabuf_put_data(data->inbuf, pos, len);
994 data->in_frag_pos += len;
995 pos = wpabuf_head_u8(data->inbuf);
996 len = data->in_frag_pos;
997 wpa_printf(MSG_DEBUG, "EAP-pwd: Last fragment, %d bytes",
1000 switch (EAP_PWD_GET_EXCHANGE(lm_exch)) {
1001 case EAP_PWD_OPCODE_ID_EXCH:
1002 eap_pwd_process_id_resp(sm, data, pos, len);
1004 case EAP_PWD_OPCODE_COMMIT_EXCH:
1005 eap_pwd_process_commit_resp(sm, data, pos, len);
1007 case EAP_PWD_OPCODE_CONFIRM_EXCH:
1008 eap_pwd_process_confirm_resp(sm, data, pos, len);
1012 * if we had been buffering fragments, here's a great place
1015 if (data->in_frag_pos) {
1016 wpabuf_free(data->inbuf);
1018 data->in_frag_pos = 0;
1023 static u8 * eap_pwd_getkey(struct eap_sm *sm, void *priv, size_t *len)
1025 struct eap_pwd_data *data = priv;
1028 if (data->state != SUCCESS)
1031 key = os_malloc(EAP_MSK_LEN);
1035 os_memcpy(key, data->msk, EAP_MSK_LEN);
1042 static u8 * eap_pwd_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
1044 struct eap_pwd_data *data = priv;
1047 if (data->state != SUCCESS)
1050 key = os_malloc(EAP_EMSK_LEN);
1054 os_memcpy(key, data->emsk, EAP_EMSK_LEN);
1055 *len = EAP_EMSK_LEN;
1061 static Boolean eap_pwd_is_success(struct eap_sm *sm, void *priv)
1063 struct eap_pwd_data *data = priv;
1064 return data->state == SUCCESS;
1068 static Boolean eap_pwd_is_done(struct eap_sm *sm, void *priv)
1070 struct eap_pwd_data *data = priv;
1071 return (data->state == SUCCESS) || (data->state == FAILURE);
1075 static u8 * eap_pwd_get_session_id(struct eap_sm *sm, void *priv, size_t *len)
1077 struct eap_pwd_data *data = priv;
1080 if (data->state != SUCCESS)
1083 id = os_malloc(1 + SHA256_MAC_LEN);
1087 os_memcpy(id, data->session_id, 1 + SHA256_MAC_LEN);
1088 *len = 1 + SHA256_MAC_LEN;
1094 int eap_server_pwd_register(void)
1096 struct eap_method *eap;
1103 (void) gettimeofday(&tp, &tz);
1104 sr ^= (tp.tv_sec ^ tp.tv_usec);
1107 eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
1108 EAP_VENDOR_IETF, EAP_TYPE_PWD,
1113 eap->init = eap_pwd_init;
1114 eap->reset = eap_pwd_reset;
1115 eap->buildReq = eap_pwd_build_req;
1116 eap->check = eap_pwd_check;
1117 eap->process = eap_pwd_process;
1118 eap->isDone = eap_pwd_is_done;
1119 eap->getKey = eap_pwd_getkey;
1120 eap->get_emsk = eap_pwd_get_emsk;
1121 eap->isSuccess = eap_pwd_is_success;
1122 eap->getSessionId = eap_pwd_get_session_id;
1124 ret = eap_server_method_register(eap);
1126 eap_server_method_free(eap);