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      1 /*
      2  * EAP peer method: EAP-EKE (RFC 6124)
      3  * Copyright (c) 2013, Jouni Malinen <j (at) w1.fi>
      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/random.h"
     13 #include "eap_peer/eap_i.h"
     14 #include "eap_common/eap_eke_common.h"
     15 
     16 struct eap_eke_data {
     17 	enum {
     18 		IDENTITY, COMMIT, CONFIRM, SUCCESS, FAILURE
     19 	} state;
     20 	u8 msk[EAP_MSK_LEN];
     21 	u8 emsk[EAP_EMSK_LEN];
     22 	u8 *peerid;
     23 	size_t peerid_len;
     24 	u8 *serverid;
     25 	size_t serverid_len;
     26 	u8 dh_priv[EAP_EKE_MAX_DH_LEN];
     27 	struct eap_eke_session sess;
     28 	u8 nonce_p[EAP_EKE_MAX_NONCE_LEN];
     29 	u8 nonce_s[EAP_EKE_MAX_NONCE_LEN];
     30 	struct wpabuf *msgs;
     31 };
     32 
     33 
     34 static const char * eap_eke_state_txt(int state)
     35 {
     36 	switch (state) {
     37 	case IDENTITY:
     38 		return "IDENTITY";
     39 	case COMMIT:
     40 		return "COMMIT";
     41 	case CONFIRM:
     42 		return "CONFIRM";
     43 	case SUCCESS:
     44 		return "SUCCESS";
     45 	case FAILURE:
     46 		return "FAILURE";
     47 	default:
     48 		return "?";
     49 	}
     50 }
     51 
     52 
     53 static void eap_eke_state(struct eap_eke_data *data, int state)
     54 {
     55 	wpa_printf(MSG_DEBUG, "EAP-EKE: %s -> %s",
     56 		   eap_eke_state_txt(data->state), eap_eke_state_txt(state));
     57 	data->state = state;
     58 }
     59 
     60 
     61 static void eap_eke_deinit(struct eap_sm *sm, void *priv);
     62 
     63 
     64 static void * eap_eke_init(struct eap_sm *sm)
     65 {
     66 	struct eap_eke_data *data;
     67 	const u8 *identity, *password;
     68 	size_t identity_len, password_len;
     69 
     70 	password = eap_get_config_password(sm, &password_len);
     71 	if (!password) {
     72 		wpa_printf(MSG_INFO, "EAP-EKE: No password configured");
     73 		return NULL;
     74 	}
     75 
     76 	data = os_zalloc(sizeof(*data));
     77 	if (data == NULL)
     78 		return NULL;
     79 	eap_eke_state(data, IDENTITY);
     80 
     81 	identity = eap_get_config_identity(sm, &identity_len);
     82 	if (identity) {
     83 		data->peerid = os_malloc(identity_len);
     84 		if (data->peerid == NULL) {
     85 			eap_eke_deinit(sm, data);
     86 			return NULL;
     87 		}
     88 		os_memcpy(data->peerid, identity, identity_len);
     89 		data->peerid_len = identity_len;
     90 	}
     91 
     92 	return data;
     93 }
     94 
     95 
     96 static void eap_eke_deinit(struct eap_sm *sm, void *priv)
     97 {
     98 	struct eap_eke_data *data = priv;
     99 	eap_eke_session_clean(&data->sess);
    100 	os_free(data->serverid);
    101 	os_free(data->peerid);
    102 	wpabuf_free(data->msgs);
    103 	os_free(data);
    104 }
    105 
    106 
    107 static struct wpabuf * eap_eke_build_msg(struct eap_eke_data *data, int id,
    108 					 size_t length, u8 eke_exch)
    109 {
    110 	struct wpabuf *msg;
    111 	size_t plen;
    112 
    113 	plen = 1 + length;
    114 
    115 	msg = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_EKE, plen,
    116 			    EAP_CODE_RESPONSE, id);
    117 	if (msg == NULL) {
    118 		wpa_printf(MSG_ERROR, "EAP-EKE: Failed to allocate memory");
    119 		return NULL;
    120 	}
    121 
    122 	wpabuf_put_u8(msg, eke_exch);
    123 
    124 	return msg;
    125 }
    126 
    127 
    128 static int eap_eke_supp_dhgroup(u8 dhgroup)
    129 {
    130 	return dhgroup == EAP_EKE_DHGROUP_EKE_2 ||
    131 		dhgroup == EAP_EKE_DHGROUP_EKE_5 ||
    132 		dhgroup == EAP_EKE_DHGROUP_EKE_14 ||
    133 		dhgroup == EAP_EKE_DHGROUP_EKE_15 ||
    134 		dhgroup == EAP_EKE_DHGROUP_EKE_16;
    135 }
    136 
    137 
    138 static int eap_eke_supp_encr(u8 encr)
    139 {
    140 	return encr == EAP_EKE_ENCR_AES128_CBC;
    141 }
    142 
    143 
    144 static int eap_eke_supp_prf(u8 prf)
    145 {
    146 	return prf == EAP_EKE_PRF_HMAC_SHA1 ||
    147 		prf == EAP_EKE_PRF_HMAC_SHA2_256;
    148 }
    149 
    150 
    151 static int eap_eke_supp_mac(u8 mac)
    152 {
    153 	return mac == EAP_EKE_MAC_HMAC_SHA1 ||
    154 		mac == EAP_EKE_MAC_HMAC_SHA2_256;
    155 }
    156 
    157 
    158 static struct wpabuf * eap_eke_build_fail(struct eap_eke_data *data,
    159 					  struct eap_method_ret *ret,
    160 					  const struct wpabuf *reqData,
    161 					  u32 failure_code)
    162 {
    163 	struct wpabuf *resp;
    164 
    165 	wpa_printf(MSG_DEBUG, "EAP-EKE: Sending EAP-EKE-Failure/Response - code=0x%x",
    166 		   failure_code);
    167 
    168 	resp = eap_eke_build_msg(data, eap_get_id(reqData), 4, EAP_EKE_FAILURE);
    169 	if (resp)
    170 		wpabuf_put_be32(resp, failure_code);
    171 
    172 	os_memset(data->dh_priv, 0, sizeof(data->dh_priv));
    173 	eap_eke_session_clean(&data->sess);
    174 
    175 	eap_eke_state(data, FAILURE);
    176 	ret->methodState = METHOD_DONE;
    177 	ret->decision = DECISION_FAIL;
    178 	ret->allowNotifications = FALSE;
    179 
    180 	return resp;
    181 }
    182 
    183 
    184 static struct wpabuf * eap_eke_process_id(struct eap_eke_data *data,
    185 					  struct eap_method_ret *ret,
    186 					  const struct wpabuf *reqData,
    187 					  const u8 *payload,
    188 					  size_t payload_len)
    189 {
    190 	struct wpabuf *resp;
    191 	unsigned num_prop, i;
    192 	const u8 *pos, *end;
    193 	const u8 *prop = NULL;
    194 	u8 idtype;
    195 
    196 	if (data->state != IDENTITY) {
    197 		return eap_eke_build_fail(data, ret, reqData,
    198 					  EAP_EKE_FAIL_PROTO_ERROR);
    199 	}
    200 
    201 	wpa_printf(MSG_DEBUG, "EAP-EKE: Received EAP-EKE-ID/Request");
    202 
    203 	if (payload_len < 2 + 4) {
    204 		wpa_printf(MSG_DEBUG, "EAP-EKE: Too short ID/Request Data");
    205 		return eap_eke_build_fail(data, ret, reqData,
    206 					  EAP_EKE_FAIL_PROTO_ERROR);
    207 	}
    208 
    209 	pos = payload;
    210 	end = payload + payload_len;
    211 
    212 	num_prop = *pos++;
    213 	pos++; /* Ignore Reserved field */
    214 
    215 	if (pos + num_prop * 4 > end) {
    216 		wpa_printf(MSG_DEBUG, "EAP-EKE: Too short ID/Request Data (num_prop=%u)",
    217 			   num_prop);
    218 		return eap_eke_build_fail(data, ret, reqData,
    219 					  EAP_EKE_FAIL_PROTO_ERROR);
    220 	}
    221 
    222 	for (i = 0; i < num_prop; i++) {
    223 		const u8 *tmp = pos;
    224 
    225 		wpa_printf(MSG_DEBUG, "EAP-EKE: Proposal #%u: dh=%u encr=%u prf=%u mac=%u",
    226 			   i, pos[0], pos[1], pos[2], pos[3]);
    227 		pos += 4;
    228 
    229 		if (!eap_eke_supp_dhgroup(*tmp))
    230 			continue;
    231 		tmp++;
    232 		if (!eap_eke_supp_encr(*tmp))
    233 			continue;
    234 		tmp++;
    235 		if (!eap_eke_supp_prf(*tmp))
    236 			continue;
    237 		tmp++;
    238 		if (!eap_eke_supp_mac(*tmp))
    239 			continue;
    240 
    241 		prop = tmp - 3;
    242 		if (eap_eke_session_init(&data->sess, prop[0], prop[1], prop[2],
    243 					 prop[3]) < 0) {
    244 			prop = NULL;
    245 			continue;
    246 		}
    247 
    248 		wpa_printf(MSG_DEBUG, "EAP-EKE: Selected proposal");
    249 		break;
    250 	}
    251 
    252 	if (prop == NULL) {
    253 		wpa_printf(MSG_DEBUG, "EAP-EKE: No acceptable proposal found");
    254 		return eap_eke_build_fail(data, ret, reqData,
    255 					  EAP_EKE_FAIL_NO_PROPOSAL_CHOSEN);
    256 	}
    257 
    258 	pos += (num_prop - i - 1) * 4;
    259 
    260 	if (pos == end) {
    261 		wpa_printf(MSG_DEBUG, "EAP-EKE: Too short ID/Request Data to include IDType/Identity");
    262 		return eap_eke_build_fail(data, ret, reqData,
    263 					  EAP_EKE_FAIL_PROTO_ERROR);
    264 	}
    265 
    266 	idtype = *pos++;
    267 	wpa_printf(MSG_DEBUG, "EAP-EKE: Server IDType %u", idtype);
    268 	wpa_hexdump_ascii(MSG_DEBUG, "EAP-EKE: Server Identity",
    269 			  pos, end - pos);
    270 	os_free(data->serverid);
    271 	data->serverid = os_malloc(end - pos);
    272 	if (data->serverid == NULL) {
    273 		return eap_eke_build_fail(data, ret, reqData,
    274 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
    275 	}
    276 	os_memcpy(data->serverid, pos, end - pos);
    277 	data->serverid_len = end - pos;
    278 
    279 	wpa_printf(MSG_DEBUG, "EAP-EKE: Sending EAP-EKE-ID/Response");
    280 
    281 	resp = eap_eke_build_msg(data, eap_get_id(reqData),
    282 				 2 + 4 + 1 + data->peerid_len,
    283 				 EAP_EKE_ID);
    284 	if (resp == NULL) {
    285 		return eap_eke_build_fail(data, ret, reqData,
    286 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
    287 	}
    288 
    289 	wpabuf_put_u8(resp, 1); /* NumProposals */
    290 	wpabuf_put_u8(resp, 0); /* Reserved */
    291 	wpabuf_put_data(resp, prop, 4); /* Selected Proposal */
    292 	wpabuf_put_u8(resp, EAP_EKE_ID_NAI);
    293 	if (data->peerid)
    294 		wpabuf_put_data(resp, data->peerid, data->peerid_len);
    295 
    296 	wpabuf_free(data->msgs);
    297 	data->msgs = wpabuf_alloc(wpabuf_len(reqData) + wpabuf_len(resp));
    298 	if (data->msgs == NULL) {
    299 		wpabuf_free(resp);
    300 		return eap_eke_build_fail(data, ret, reqData,
    301 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
    302 	}
    303 	wpabuf_put_buf(data->msgs, reqData);
    304 	wpabuf_put_buf(data->msgs, resp);
    305 
    306 	eap_eke_state(data, COMMIT);
    307 
    308 	return resp;
    309 }
    310 
    311 
    312 static struct wpabuf * eap_eke_process_commit(struct eap_sm *sm,
    313 					      struct eap_eke_data *data,
    314 					      struct eap_method_ret *ret,
    315 					      const struct wpabuf *reqData,
    316 					      const u8 *payload,
    317 					      size_t payload_len)
    318 {
    319 	struct wpabuf *resp;
    320 	const u8 *pos, *end, *dhcomp;
    321 	size_t prot_len;
    322 	u8 *rpos;
    323 	u8 key[EAP_EKE_MAX_KEY_LEN];
    324 	u8 pub[EAP_EKE_MAX_DH_LEN];
    325 	const u8 *password;
    326 	size_t password_len;
    327 
    328 	if (data->state != COMMIT) {
    329 		wpa_printf(MSG_DEBUG, "EAP-EKE: EAP-EKE-Commit/Request received in unexpected state (%d)", data->state);
    330 		return eap_eke_build_fail(data, ret, reqData,
    331 					  EAP_EKE_FAIL_PROTO_ERROR);
    332 	}
    333 
    334 	wpa_printf(MSG_DEBUG, "EAP-EKE: Received EAP-EKE-Commit/Request");
    335 
    336 	password = eap_get_config_password(sm, &password_len);
    337 	if (password == NULL) {
    338 		wpa_printf(MSG_INFO, "EAP-EKE: No password configured!");
    339 		return eap_eke_build_fail(data, ret, reqData,
    340 					  EAP_EKE_FAIL_PASSWD_NOT_FOUND);
    341 	}
    342 
    343 	pos = payload;
    344 	end = payload + payload_len;
    345 
    346 	if (pos + data->sess.dhcomp_len > end) {
    347 		wpa_printf(MSG_DEBUG, "EAP-EKE: Too short EAP-EKE-Commit");
    348 		return eap_eke_build_fail(data, ret, reqData,
    349 					  EAP_EKE_FAIL_PROTO_ERROR);
    350 	}
    351 
    352 	wpa_hexdump(MSG_DEBUG, "EAP-EKE: DHComponent_S",
    353 		    pos, data->sess.dhcomp_len);
    354 	dhcomp = pos;
    355 	pos += data->sess.dhcomp_len;
    356 	wpa_hexdump(MSG_DEBUG, "EAP-EKE: CBValue", pos, end - pos);
    357 
    358 	/*
    359 	 * temp = prf(0+, password)
    360 	 * key = prf+(temp, ID_S | ID_P)
    361 	 */
    362 	if (eap_eke_derive_key(&data->sess, password, password_len,
    363 			       data->serverid, data->serverid_len,
    364 			       data->peerid, data->peerid_len, key) < 0) {
    365 		wpa_printf(MSG_INFO, "EAP-EKE: Failed to derive key");
    366 		return eap_eke_build_fail(data, ret, reqData,
    367 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
    368 	}
    369 
    370 	/*
    371 	 * y_p = g ^ x_p (mod p)
    372 	 * x_p = random number 2 .. p-1
    373 	 */
    374 	if (eap_eke_dh_init(data->sess.dhgroup, data->dh_priv, pub) < 0) {
    375 		wpa_printf(MSG_INFO, "EAP-EKE: Failed to initialize DH");
    376 		os_memset(key, 0, sizeof(key));
    377 		return eap_eke_build_fail(data, ret, reqData,
    378 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
    379 	}
    380 
    381 	if (eap_eke_shared_secret(&data->sess, key, data->dh_priv, dhcomp) < 0)
    382 	{
    383 		wpa_printf(MSG_INFO, "EAP-EKE: Failed to derive shared secret");
    384 		os_memset(key, 0, sizeof(key));
    385 		return eap_eke_build_fail(data, ret, reqData,
    386 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
    387 	}
    388 
    389 	if (eap_eke_derive_ke_ki(&data->sess,
    390 				 data->serverid, data->serverid_len,
    391 				 data->peerid, data->peerid_len) < 0) {
    392 		wpa_printf(MSG_INFO, "EAP-EKE: Failed to derive Ke/Ki");
    393 		os_memset(key, 0, sizeof(key));
    394 		return eap_eke_build_fail(data, ret, reqData,
    395 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
    396 	}
    397 
    398 	wpa_printf(MSG_DEBUG, "EAP-EKE: Sending EAP-EKE-Commit/Response");
    399 
    400 	resp = eap_eke_build_msg(data, eap_get_id(reqData),
    401 				 data->sess.dhcomp_len + data->sess.pnonce_len,
    402 				 EAP_EKE_COMMIT);
    403 	if (resp == NULL) {
    404 		os_memset(key, 0, sizeof(key));
    405 		return eap_eke_build_fail(data, ret, reqData,
    406 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
    407 	}
    408 
    409 	/* DHComponent_P = Encr(key, y_p) */
    410 	rpos = wpabuf_put(resp, data->sess.dhcomp_len);
    411 	if (eap_eke_dhcomp(&data->sess, key, pub, rpos) < 0) {
    412 		wpa_printf(MSG_INFO, "EAP-EKE: Failed to build DHComponent_S");
    413 		os_memset(key, 0, sizeof(key));
    414 		return eap_eke_build_fail(data, ret, reqData,
    415 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
    416 	}
    417 	os_memset(key, 0, sizeof(key));
    418 
    419 	wpa_hexdump(MSG_DEBUG, "EAP-EKE: DHComponent_P",
    420 		    rpos, data->sess.dhcomp_len);
    421 
    422 	if (random_get_bytes(data->nonce_p, data->sess.nonce_len)) {
    423 		wpabuf_free(resp);
    424 		return eap_eke_build_fail(data, ret, reqData,
    425 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
    426 	}
    427 	wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: Nonce_P",
    428 			data->nonce_p, data->sess.nonce_len);
    429 	prot_len = wpabuf_tailroom(resp);
    430 	if (eap_eke_prot(&data->sess, data->nonce_p, data->sess.nonce_len,
    431 			 wpabuf_put(resp, 0), &prot_len) < 0) {
    432 		wpabuf_free(resp);
    433 		return eap_eke_build_fail(data, ret, reqData,
    434 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
    435 	}
    436 	wpa_hexdump(MSG_DEBUG, "EAP-EKE: PNonce_P",
    437 		    wpabuf_put(resp, 0), prot_len);
    438 	wpabuf_put(resp, prot_len);
    439 
    440 	/* TODO: CBValue */
    441 
    442 	if (wpabuf_resize(&data->msgs, wpabuf_len(reqData) + wpabuf_len(resp))
    443 	    < 0) {
    444 		wpabuf_free(resp);
    445 		return eap_eke_build_fail(data, ret, reqData,
    446 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
    447 	}
    448 	wpabuf_put_buf(data->msgs, reqData);
    449 	wpabuf_put_buf(data->msgs, resp);
    450 
    451 	eap_eke_state(data, CONFIRM);
    452 
    453 	return resp;
    454 }
    455 
    456 
    457 static struct wpabuf * eap_eke_process_confirm(struct eap_eke_data *data,
    458 					       struct eap_method_ret *ret,
    459 					       const struct wpabuf *reqData,
    460 					       const u8 *payload,
    461 					       size_t payload_len)
    462 {
    463 	struct wpabuf *resp;
    464 	const u8 *pos, *end;
    465 	size_t prot_len;
    466 	u8 nonces[2 * EAP_EKE_MAX_NONCE_LEN];
    467 	u8 auth_s[EAP_EKE_MAX_HASH_LEN];
    468 	size_t decrypt_len;
    469 	u8 *auth;
    470 
    471 	if (data->state != CONFIRM) {
    472 		wpa_printf(MSG_DEBUG, "EAP-EKE: EAP-EKE-Confirm/Request received in unexpected state (%d)",
    473 			   data->state);
    474 		return eap_eke_build_fail(data, ret, reqData,
    475 					  EAP_EKE_FAIL_PROTO_ERROR);
    476 	}
    477 
    478 	wpa_printf(MSG_DEBUG, "EAP-EKE: Received EAP-EKE-Confirm/Request");
    479 
    480 	pos = payload;
    481 	end = payload + payload_len;
    482 
    483 	if (pos + data->sess.pnonce_ps_len + data->sess.prf_len > end) {
    484 		wpa_printf(MSG_DEBUG, "EAP-EKE: Too short EAP-EKE-Commit");
    485 		return eap_eke_build_fail(data, ret, reqData,
    486 					  EAP_EKE_FAIL_PROTO_ERROR);
    487 	}
    488 
    489 	decrypt_len = sizeof(nonces);
    490 	if (eap_eke_decrypt_prot(&data->sess, pos, data->sess.pnonce_ps_len,
    491 				 nonces, &decrypt_len) < 0) {
    492 		wpa_printf(MSG_INFO, "EAP-EKE: Failed to decrypt PNonce_PS");
    493 		return eap_eke_build_fail(data, ret, reqData,
    494 					  EAP_EKE_FAIL_AUTHENTICATION_FAIL);
    495 	}
    496 	if (decrypt_len != (size_t) 2 * data->sess.nonce_len) {
    497 		wpa_printf(MSG_INFO, "EAP-EKE: PNonce_PS protected data length does not match length of Nonce_P and Nonce_S");
    498 		return eap_eke_build_fail(data, ret, reqData,
    499 					  EAP_EKE_FAIL_AUTHENTICATION_FAIL);
    500 	}
    501 	wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: Received Nonce_P | Nonce_S",
    502 			nonces, 2 * data->sess.nonce_len);
    503 	if (os_memcmp(data->nonce_p, nonces, data->sess.nonce_len) != 0) {
    504 		wpa_printf(MSG_INFO, "EAP-EKE: Received Nonce_P does not match trnsmitted Nonce_P");
    505 		return eap_eke_build_fail(data, ret, reqData,
    506 					  EAP_EKE_FAIL_AUTHENTICATION_FAIL);
    507 	}
    508 
    509 	os_memcpy(data->nonce_s, nonces + data->sess.nonce_len,
    510 		  data->sess.nonce_len);
    511 	wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: Nonce_S",
    512 			data->nonce_s, data->sess.nonce_len);
    513 
    514 	if (eap_eke_derive_ka(&data->sess, data->serverid, data->serverid_len,
    515 			      data->peerid, data->peerid_len,
    516 			      data->nonce_p, data->nonce_s) < 0) {
    517 		return eap_eke_build_fail(data, ret, reqData,
    518 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
    519 	}
    520 
    521 	if (eap_eke_auth(&data->sess, "EAP-EKE server", data->msgs, auth_s) < 0)
    522 	{
    523 		return eap_eke_build_fail(data, ret, reqData,
    524 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
    525 	}
    526 	wpa_hexdump(MSG_DEBUG, "EAP-EKE: Auth_S", auth_s, data->sess.prf_len);
    527 	if (os_memcmp(auth_s, pos + data->sess.pnonce_ps_len,
    528 		      data->sess.prf_len) != 0) {
    529 		wpa_printf(MSG_INFO, "EAP-EKE: Auth_S does not match");
    530 		return eap_eke_build_fail(data, ret, reqData,
    531 					  EAP_EKE_FAIL_AUTHENTICATION_FAIL);
    532 	}
    533 
    534 	wpa_printf(MSG_DEBUG, "EAP-EKE: Sending EAP-EKE-Confirm/Response");
    535 
    536 	resp = eap_eke_build_msg(data, eap_get_id(reqData),
    537 				 data->sess.pnonce_len + data->sess.prf_len,
    538 				 EAP_EKE_CONFIRM);
    539 	if (resp == NULL) {
    540 		return eap_eke_build_fail(data, ret, reqData,
    541 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
    542 	}
    543 
    544 	prot_len = wpabuf_tailroom(resp);
    545 	if (eap_eke_prot(&data->sess, data->nonce_s, data->sess.nonce_len,
    546 			 wpabuf_put(resp, 0), &prot_len) < 0) {
    547 		wpabuf_free(resp);
    548 		return eap_eke_build_fail(data, ret, reqData,
    549 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
    550 	}
    551 	wpabuf_put(resp, prot_len);
    552 
    553 	auth = wpabuf_put(resp, data->sess.prf_len);
    554 	if (eap_eke_auth(&data->sess, "EAP-EKE peer", data->msgs, auth) < 0) {
    555 		wpabuf_free(resp);
    556 		return eap_eke_build_fail(data, ret, reqData,
    557 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
    558 	}
    559 	wpa_hexdump(MSG_DEBUG, "EAP-EKE: Auth_P", auth, data->sess.prf_len);
    560 
    561 	if (eap_eke_derive_msk(&data->sess, data->serverid, data->serverid_len,
    562 			       data->peerid, data->peerid_len,
    563 			       data->nonce_s, data->nonce_p,
    564 			       data->msk, data->emsk) < 0) {
    565 		wpa_printf(MSG_INFO, "EAP-EKE: Failed to derive MSK/EMSK");
    566 		wpabuf_free(resp);
    567 		return eap_eke_build_fail(data, ret, reqData,
    568 					  EAP_EKE_FAIL_PRIVATE_INTERNAL_ERROR);
    569 	}
    570 
    571 	os_memset(data->dh_priv, 0, sizeof(data->dh_priv));
    572 	eap_eke_session_clean(&data->sess);
    573 
    574 	eap_eke_state(data, SUCCESS);
    575 	ret->methodState = METHOD_MAY_CONT;
    576 	ret->decision = DECISION_COND_SUCC;
    577 	ret->allowNotifications = FALSE;
    578 
    579 	return resp;
    580 }
    581 
    582 
    583 static struct wpabuf * eap_eke_process_failure(struct eap_eke_data *data,
    584 					       struct eap_method_ret *ret,
    585 					       const struct wpabuf *reqData,
    586 					       const u8 *payload,
    587 					       size_t payload_len)
    588 {
    589 	wpa_printf(MSG_DEBUG, "EAP-EKE: Received EAP-EKE-Failure/Request");
    590 
    591 	if (payload_len < 4) {
    592 		wpa_printf(MSG_DEBUG, "EAP-EKE: Too short EAP-EKE-Failure");
    593 	} else {
    594 		u32 code;
    595 		code = WPA_GET_BE32(payload);
    596 		wpa_printf(MSG_INFO, "EAP-EKE: Failure-Code 0x%x", code);
    597 	}
    598 
    599 	return eap_eke_build_fail(data, ret, reqData, EAP_EKE_FAIL_NO_ERROR);
    600 }
    601 
    602 
    603 static struct wpabuf * eap_eke_process(struct eap_sm *sm, void *priv,
    604 				       struct eap_method_ret *ret,
    605 				       const struct wpabuf *reqData)
    606 {
    607 	struct eap_eke_data *data = priv;
    608 	struct wpabuf *resp;
    609 	const u8 *pos, *end;
    610 	size_t len;
    611 	u8 eke_exch;
    612 
    613 	pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_EKE, reqData, &len);
    614 	if (pos == NULL || len < 1) {
    615 		ret->ignore = TRUE;
    616 		return NULL;
    617 	}
    618 
    619 	end = pos + len;
    620 	eke_exch = *pos++;
    621 
    622 	wpa_printf(MSG_DEBUG, "EAP-EKE: Received frame: exch %d", eke_exch);
    623 	wpa_hexdump(MSG_DEBUG, "EAP-EKE: Received Data", pos, end - pos);
    624 
    625 	ret->ignore = FALSE;
    626 	ret->methodState = METHOD_MAY_CONT;
    627 	ret->decision = DECISION_FAIL;
    628 	ret->allowNotifications = TRUE;
    629 
    630 	switch (eke_exch) {
    631 	case EAP_EKE_ID:
    632 		resp = eap_eke_process_id(data, ret, reqData, pos, end - pos);
    633 		break;
    634 	case EAP_EKE_COMMIT:
    635 		resp = eap_eke_process_commit(sm, data, ret, reqData,
    636 					      pos, end - pos);
    637 		break;
    638 	case EAP_EKE_CONFIRM:
    639 		resp = eap_eke_process_confirm(data, ret, reqData,
    640 					       pos, end - pos);
    641 		break;
    642 	case EAP_EKE_FAILURE:
    643 		resp = eap_eke_process_failure(data, ret, reqData,
    644 					       pos, end - pos);
    645 		break;
    646 	default:
    647 		wpa_printf(MSG_DEBUG, "EAP-EKE: Ignoring message with unknown EKE-Exch %d", eke_exch);
    648 		ret->ignore = TRUE;
    649 		return NULL;
    650 	}
    651 
    652 	if (ret->methodState == METHOD_DONE)
    653 		ret->allowNotifications = FALSE;
    654 
    655 	return resp;
    656 }
    657 
    658 
    659 static Boolean eap_eke_isKeyAvailable(struct eap_sm *sm, void *priv)
    660 {
    661 	struct eap_eke_data *data = priv;
    662 	return data->state == SUCCESS;
    663 }
    664 
    665 
    666 static u8 * eap_eke_getKey(struct eap_sm *sm, void *priv, size_t *len)
    667 {
    668 	struct eap_eke_data *data = priv;
    669 	u8 *key;
    670 
    671 	if (data->state != SUCCESS)
    672 		return NULL;
    673 
    674 	key = os_malloc(EAP_MSK_LEN);
    675 	if (key == NULL)
    676 		return NULL;
    677 	os_memcpy(key, data->msk, EAP_MSK_LEN);
    678 	*len = EAP_MSK_LEN;
    679 
    680 	return key;
    681 }
    682 
    683 
    684 static u8 * eap_eke_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
    685 {
    686 	struct eap_eke_data *data = priv;
    687 	u8 *key;
    688 
    689 	if (data->state != SUCCESS)
    690 		return NULL;
    691 
    692 	key = os_malloc(EAP_EMSK_LEN);
    693 	if (key == NULL)
    694 		return NULL;
    695 	os_memcpy(key, data->emsk, EAP_EMSK_LEN);
    696 	*len = EAP_EMSK_LEN;
    697 
    698 	return key;
    699 }
    700 
    701 
    702 int eap_peer_eke_register(void)
    703 {
    704 	struct eap_method *eap;
    705 	int ret;
    706 
    707 	eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
    708 				    EAP_VENDOR_IETF, EAP_TYPE_EKE, "EKE");
    709 	if (eap == NULL)
    710 		return -1;
    711 
    712 	eap->init = eap_eke_init;
    713 	eap->deinit = eap_eke_deinit;
    714 	eap->process = eap_eke_process;
    715 	eap->isKeyAvailable = eap_eke_isKeyAvailable;
    716 	eap->getKey = eap_eke_getKey;
    717 	eap->get_emsk = eap_eke_get_emsk;
    718 
    719 	ret = eap_peer_method_register(eap);
    720 	if (ret)
    721 		eap_peer_method_free(eap);
    722 	return ret;
    723 }
    724