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      1 /*
      2  * EAP server/peer: EAP-EKE shared routines
      3  * Copyright (c) 2011-2013, 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/aes.h"
     13 #include "crypto/aes_wrap.h"
     14 #include "crypto/crypto.h"
     15 #include "crypto/dh_groups.h"
     16 #include "crypto/random.h"
     17 #include "crypto/sha1.h"
     18 #include "crypto/sha256.h"
     19 #include "eap_common/eap_defs.h"
     20 #include "eap_eke_common.h"
     21 
     22 
     23 static int eap_eke_dh_len(u8 group)
     24 {
     25 	switch (group) {
     26 	case EAP_EKE_DHGROUP_EKE_2:
     27 		return 128;
     28 	case EAP_EKE_DHGROUP_EKE_5:
     29 		return 192;
     30 	case EAP_EKE_DHGROUP_EKE_14:
     31 		return 256;
     32 	case EAP_EKE_DHGROUP_EKE_15:
     33 		return 384;
     34 	case EAP_EKE_DHGROUP_EKE_16:
     35 		return 512;
     36 	}
     37 
     38 	return -1;
     39 }
     40 
     41 
     42 static int eap_eke_dhcomp_len(u8 dhgroup, u8 encr)
     43 {
     44 	int dhlen;
     45 
     46 	dhlen = eap_eke_dh_len(dhgroup);
     47 	if (dhlen < 0 || encr != EAP_EKE_ENCR_AES128_CBC)
     48 		return -1;
     49 	return AES_BLOCK_SIZE + dhlen;
     50 }
     51 
     52 
     53 static const struct dh_group * eap_eke_dh_group(u8 group)
     54 {
     55 	switch (group) {
     56 	case EAP_EKE_DHGROUP_EKE_2:
     57 		return dh_groups_get(2);
     58 	case EAP_EKE_DHGROUP_EKE_5:
     59 		return dh_groups_get(5);
     60 	case EAP_EKE_DHGROUP_EKE_14:
     61 		return dh_groups_get(14);
     62 	case EAP_EKE_DHGROUP_EKE_15:
     63 		return dh_groups_get(15);
     64 	case EAP_EKE_DHGROUP_EKE_16:
     65 		return dh_groups_get(16);
     66 	}
     67 
     68 	return NULL;
     69 }
     70 
     71 
     72 static int eap_eke_dh_generator(u8 group)
     73 {
     74 	switch (group) {
     75 	case EAP_EKE_DHGROUP_EKE_2:
     76 		return 5;
     77 	case EAP_EKE_DHGROUP_EKE_5:
     78 		return 31;
     79 	case EAP_EKE_DHGROUP_EKE_14:
     80 		return 11;
     81 	case EAP_EKE_DHGROUP_EKE_15:
     82 		return 5;
     83 	case EAP_EKE_DHGROUP_EKE_16:
     84 		return 5;
     85 	}
     86 
     87 	return -1;
     88 }
     89 
     90 
     91 static int eap_eke_pnonce_len(u8 mac)
     92 {
     93 	int mac_len;
     94 
     95 	if (mac == EAP_EKE_MAC_HMAC_SHA1)
     96 		mac_len = SHA1_MAC_LEN;
     97 	else if (mac == EAP_EKE_MAC_HMAC_SHA2_256)
     98 		mac_len = SHA256_MAC_LEN;
     99 	else
    100 		return -1;
    101 
    102 	return AES_BLOCK_SIZE + 16 + mac_len;
    103 }
    104 
    105 
    106 static int eap_eke_pnonce_ps_len(u8 mac)
    107 {
    108 	int mac_len;
    109 
    110 	if (mac == EAP_EKE_MAC_HMAC_SHA1)
    111 		mac_len = SHA1_MAC_LEN;
    112 	else if (mac == EAP_EKE_MAC_HMAC_SHA2_256)
    113 		mac_len = SHA256_MAC_LEN;
    114 	else
    115 		return -1;
    116 
    117 	return AES_BLOCK_SIZE + 2 * 16 + mac_len;
    118 }
    119 
    120 
    121 static int eap_eke_prf_len(u8 prf)
    122 {
    123 	if (prf == EAP_EKE_PRF_HMAC_SHA1)
    124 		return 20;
    125 	if (prf == EAP_EKE_PRF_HMAC_SHA2_256)
    126 		return 32;
    127 	return -1;
    128 }
    129 
    130 
    131 static int eap_eke_nonce_len(u8 prf)
    132 {
    133 	int prf_len;
    134 
    135 	prf_len = eap_eke_prf_len(prf);
    136 	if (prf_len < 0)
    137 		return -1;
    138 
    139 	if (prf_len > 2 * 16)
    140 		return (prf_len + 1) / 2;
    141 
    142 	return 16;
    143 }
    144 
    145 
    146 static int eap_eke_auth_len(u8 prf)
    147 {
    148 	switch (prf) {
    149 	case EAP_EKE_PRF_HMAC_SHA1:
    150 		return SHA1_MAC_LEN;
    151 	case EAP_EKE_PRF_HMAC_SHA2_256:
    152 		return SHA256_MAC_LEN;
    153 	}
    154 
    155 	return -1;
    156 }
    157 
    158 
    159 int eap_eke_dh_init(u8 group, u8 *ret_priv, u8 *ret_pub)
    160 {
    161 	int generator;
    162 	u8 gen;
    163 	const struct dh_group *dh;
    164 
    165 	generator = eap_eke_dh_generator(group);
    166 	dh = eap_eke_dh_group(group);
    167 	if (generator < 0 || generator > 255 || !dh)
    168 		return -1;
    169 	gen = generator;
    170 
    171 	if (crypto_dh_init(gen, dh->prime, dh->prime_len, ret_priv,
    172 			   ret_pub) < 0)
    173 		return -1;
    174 	wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: DH private value",
    175 			ret_priv, dh->prime_len);
    176 	wpa_hexdump(MSG_DEBUG, "EAP-EKE: DH public value",
    177 		    ret_pub, dh->prime_len);
    178 
    179 	return 0;
    180 }
    181 
    182 
    183 static int eap_eke_prf(u8 prf, const u8 *key, size_t key_len, const u8 *data,
    184 		       size_t data_len, const u8 *data2, size_t data2_len,
    185 		       u8 *res)
    186 {
    187 	const u8 *addr[2];
    188 	size_t len[2];
    189 	size_t num_elem = 1;
    190 
    191 	addr[0] = data;
    192 	len[0] = data_len;
    193 	if (data2) {
    194 		num_elem++;
    195 		addr[1] = data2;
    196 		len[1] = data2_len;
    197 	}
    198 
    199 	if (prf == EAP_EKE_PRF_HMAC_SHA1)
    200 		return hmac_sha1_vector(key, key_len, num_elem, addr, len, res);
    201 	if (prf == EAP_EKE_PRF_HMAC_SHA2_256)
    202 		return hmac_sha256_vector(key, key_len, num_elem, addr, len,
    203 					  res);
    204 	return -1;
    205 }
    206 
    207 
    208 static int eap_eke_prf_hmac_sha1(const u8 *key, size_t key_len, const u8 *data,
    209 				 size_t data_len, u8 *res, size_t len)
    210 {
    211 	u8 hash[SHA1_MAC_LEN];
    212 	u8 idx;
    213 	const u8 *addr[3];
    214 	size_t vlen[3];
    215 	int ret;
    216 
    217 	idx = 0;
    218 	addr[0] = hash;
    219 	vlen[0] = SHA1_MAC_LEN;
    220 	addr[1] = data;
    221 	vlen[1] = data_len;
    222 	addr[2] = &idx;
    223 	vlen[2] = 1;
    224 
    225 	while (len > 0) {
    226 		idx++;
    227 		if (idx == 1)
    228 			ret = hmac_sha1_vector(key, key_len, 2, &addr[1],
    229 					       &vlen[1], hash);
    230 		else
    231 			ret = hmac_sha1_vector(key, key_len, 3, addr, vlen,
    232 					       hash);
    233 		if (ret < 0)
    234 			return -1;
    235 		if (len > SHA1_MAC_LEN) {
    236 			os_memcpy(res, hash, SHA1_MAC_LEN);
    237 			res += SHA1_MAC_LEN;
    238 			len -= SHA1_MAC_LEN;
    239 		} else {
    240 			os_memcpy(res, hash, len);
    241 			len = 0;
    242 		}
    243 	}
    244 
    245 	return 0;
    246 }
    247 
    248 
    249 static int eap_eke_prf_hmac_sha256(const u8 *key, size_t key_len, const u8 *data,
    250 				   size_t data_len, u8 *res, size_t len)
    251 {
    252 	u8 hash[SHA256_MAC_LEN];
    253 	u8 idx;
    254 	const u8 *addr[3];
    255 	size_t vlen[3];
    256 	int ret;
    257 
    258 	idx = 0;
    259 	addr[0] = hash;
    260 	vlen[0] = SHA256_MAC_LEN;
    261 	addr[1] = data;
    262 	vlen[1] = data_len;
    263 	addr[2] = &idx;
    264 	vlen[2] = 1;
    265 
    266 	while (len > 0) {
    267 		idx++;
    268 		if (idx == 1)
    269 			ret = hmac_sha256_vector(key, key_len, 2, &addr[1],
    270 						 &vlen[1], hash);
    271 		else
    272 			ret = hmac_sha256_vector(key, key_len, 3, addr, vlen,
    273 						 hash);
    274 		if (ret < 0)
    275 			return -1;
    276 		if (len > SHA256_MAC_LEN) {
    277 			os_memcpy(res, hash, SHA256_MAC_LEN);
    278 			res += SHA256_MAC_LEN;
    279 			len -= SHA256_MAC_LEN;
    280 		} else {
    281 			os_memcpy(res, hash, len);
    282 			len = 0;
    283 		}
    284 	}
    285 
    286 	return 0;
    287 }
    288 
    289 
    290 static int eap_eke_prfplus(u8 prf, const u8 *key, size_t key_len,
    291 			   const u8 *data, size_t data_len, u8 *res, size_t len)
    292 {
    293 	if (prf == EAP_EKE_PRF_HMAC_SHA1)
    294 		return eap_eke_prf_hmac_sha1(key, key_len, data, data_len, res,
    295 					     len);
    296 	if (prf == EAP_EKE_PRF_HMAC_SHA2_256)
    297 		return eap_eke_prf_hmac_sha256(key, key_len, data, data_len,
    298 					       res, len);
    299 	return -1;
    300 }
    301 
    302 
    303 int eap_eke_derive_key(struct eap_eke_session *sess,
    304 		       const u8 *password, size_t password_len,
    305 		       const u8 *id_s, size_t id_s_len, const u8 *id_p,
    306 		       size_t id_p_len, u8 *key)
    307 {
    308 	u8 zeros[EAP_EKE_MAX_HASH_LEN];
    309 	u8 temp[EAP_EKE_MAX_HASH_LEN];
    310 	size_t key_len = 16; /* Only AES-128-CBC is used here */
    311 	u8 *id;
    312 
    313 	/* temp = prf(0+, password) */
    314 	os_memset(zeros, 0, sess->prf_len);
    315 	if (eap_eke_prf(sess->prf, zeros, sess->prf_len,
    316 			password, password_len, NULL, 0, temp) < 0)
    317 		return -1;
    318 	wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: temp = prf(0+, password)",
    319 			temp, sess->prf_len);
    320 
    321 	/* key = prf+(temp, ID_S | ID_P) */
    322 	id = os_malloc(id_s_len + id_p_len);
    323 	if (id == NULL)
    324 		return -1;
    325 	os_memcpy(id, id_s, id_s_len);
    326 	os_memcpy(id + id_s_len, id_p, id_p_len);
    327 	wpa_hexdump_ascii(MSG_DEBUG, "EAP-EKE: ID_S | ID_P",
    328 			  id, id_s_len + id_p_len);
    329 	if (eap_eke_prfplus(sess->prf, temp, sess->prf_len,
    330 			    id, id_s_len + id_p_len, key, key_len) < 0) {
    331 		os_free(id);
    332 		return -1;
    333 	}
    334 	os_free(id);
    335 	wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: key = prf+(temp, ID_S | ID_P)",
    336 			key, key_len);
    337 
    338 	return 0;
    339 }
    340 
    341 
    342 int eap_eke_dhcomp(struct eap_eke_session *sess, const u8 *key, const u8 *dhpub,
    343 		   u8 *ret_dhcomp)
    344 {
    345 	u8 pub[EAP_EKE_MAX_DH_LEN];
    346 	int dh_len;
    347 	u8 iv[AES_BLOCK_SIZE];
    348 
    349 	dh_len = eap_eke_dh_len(sess->dhgroup);
    350 	if (dh_len < 0)
    351 		return -1;
    352 
    353 	/*
    354 	 * DHComponent = Encr(key, y)
    355 	 *
    356 	 * All defined DH groups use primes that have length devisible by 16, so
    357 	 * no need to do extra padding for y (= pub).
    358 	 */
    359 	if (sess->encr != EAP_EKE_ENCR_AES128_CBC)
    360 		return -1;
    361 	if (random_get_bytes(iv, AES_BLOCK_SIZE))
    362 		return -1;
    363 	wpa_hexdump(MSG_DEBUG, "EAP-EKE: IV for Encr(key, y)",
    364 		    iv, AES_BLOCK_SIZE);
    365 	os_memcpy(pub, dhpub, dh_len);
    366 	if (aes_128_cbc_encrypt(key, iv, pub, dh_len) < 0)
    367 		return -1;
    368 	os_memcpy(ret_dhcomp, iv, AES_BLOCK_SIZE);
    369 	os_memcpy(ret_dhcomp + AES_BLOCK_SIZE, pub, dh_len);
    370 	wpa_hexdump(MSG_DEBUG, "EAP-EKE: DHComponent = Encr(key, y)",
    371 		    ret_dhcomp, AES_BLOCK_SIZE + dh_len);
    372 
    373 	return 0;
    374 }
    375 
    376 
    377 int eap_eke_shared_secret(struct eap_eke_session *sess, const u8 *key,
    378 			  const u8 *dhpriv, const u8 *peer_dhcomp)
    379 {
    380 	u8 zeros[EAP_EKE_MAX_HASH_LEN];
    381 	u8 peer_pub[EAP_EKE_MAX_DH_LEN];
    382 	u8 modexp[EAP_EKE_MAX_DH_LEN];
    383 	size_t len;
    384 	const struct dh_group *dh;
    385 
    386 	dh = eap_eke_dh_group(sess->dhgroup);
    387 	if (sess->encr != EAP_EKE_ENCR_AES128_CBC || !dh)
    388 		return -1;
    389 
    390 	/* Decrypt peer DHComponent */
    391 	os_memcpy(peer_pub, peer_dhcomp + AES_BLOCK_SIZE, dh->prime_len);
    392 	if (aes_128_cbc_decrypt(key, peer_dhcomp, peer_pub, dh->prime_len) < 0) {
    393 		wpa_printf(MSG_INFO, "EAP-EKE: Failed to decrypt DHComponent");
    394 		return -1;
    395 	}
    396 	wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: Decrypted peer DH pubkey",
    397 			peer_pub, dh->prime_len);
    398 
    399 	/* SharedSecret = prf(0+, g ^ (x_s * x_p) (mod p)) */
    400 	len = dh->prime_len;
    401 	if (crypto_dh_derive_secret(*dh->generator, dh->prime, dh->prime_len,
    402 				    NULL, 0, dhpriv, dh->prime_len, peer_pub,
    403 				    dh->prime_len, modexp, &len) < 0)
    404 		return -1;
    405 	if (len < dh->prime_len) {
    406 		size_t pad = dh->prime_len - len;
    407 		os_memmove(modexp + pad, modexp, len);
    408 		os_memset(modexp, 0, pad);
    409 	}
    410 
    411 	os_memset(zeros, 0, sess->auth_len);
    412 	if (eap_eke_prf(sess->prf, zeros, sess->auth_len, modexp, dh->prime_len,
    413 			NULL, 0, sess->shared_secret) < 0)
    414 		return -1;
    415 	wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: SharedSecret",
    416 			sess->shared_secret, sess->auth_len);
    417 
    418 	return 0;
    419 }
    420 
    421 
    422 int eap_eke_derive_ke_ki(struct eap_eke_session *sess,
    423 			 const u8 *id_s, size_t id_s_len,
    424 			 const u8 *id_p, size_t id_p_len)
    425 {
    426 	u8 buf[EAP_EKE_MAX_KE_LEN + EAP_EKE_MAX_KI_LEN];
    427 	size_t ke_len, ki_len;
    428 	u8 *data;
    429 	size_t data_len;
    430 	const char *label = "EAP-EKE Keys";
    431 	size_t label_len;
    432 
    433 	/*
    434 	 * Ke | Ki = prf+(SharedSecret, "EAP-EKE Keys" | ID_S | ID_P)
    435 	 * Ke = encryption key
    436 	 * Ki = integrity protection key
    437 	 * Length of each key depends on the selected algorithms.
    438 	 */
    439 
    440 	if (sess->encr == EAP_EKE_ENCR_AES128_CBC)
    441 		ke_len = 16;
    442 	else
    443 		return -1;
    444 
    445 	if (sess->mac == EAP_EKE_PRF_HMAC_SHA1)
    446 		ki_len = 20;
    447 	else if (sess->mac == EAP_EKE_PRF_HMAC_SHA2_256)
    448 		ki_len = 32;
    449 	else
    450 		return -1;
    451 
    452 	label_len = os_strlen(label);
    453 	data_len = label_len + id_s_len + id_p_len;
    454 	data = os_malloc(data_len);
    455 	if (data == NULL)
    456 		return -1;
    457 	os_memcpy(data, label, label_len);
    458 	os_memcpy(data + label_len, id_s, id_s_len);
    459 	os_memcpy(data + label_len + id_s_len, id_p, id_p_len);
    460 	if (eap_eke_prfplus(sess->prf, sess->shared_secret, sess->prf_len,
    461 			    data, data_len, buf, ke_len + ki_len) < 0) {
    462 		os_free(data);
    463 		return -1;
    464 	}
    465 
    466 	os_memcpy(sess->ke, buf, ke_len);
    467 	wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: Ke", sess->ke, ke_len);
    468 	os_memcpy(sess->ki, buf + ke_len, ki_len);
    469 	wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: Ki", sess->ki, ki_len);
    470 
    471 	os_free(data);
    472 	return 0;
    473 }
    474 
    475 
    476 int eap_eke_derive_ka(struct eap_eke_session *sess,
    477 		      const u8 *id_s, size_t id_s_len,
    478 		      const u8 *id_p, size_t id_p_len,
    479 		      const u8 *nonce_p, const u8 *nonce_s)
    480 {
    481 	u8 *data, *pos;
    482 	size_t data_len;
    483 	const char *label = "EAP-EKE Ka";
    484 	size_t label_len;
    485 
    486 	/*
    487 	 * Ka = prf+(SharedSecret, "EAP-EKE Ka" | ID_S | ID_P | Nonce_P |
    488 	 *	     Nonce_S)
    489 	 * Ka = authentication key
    490 	 * Length of the key depends on the selected algorithms.
    491 	 */
    492 
    493 	label_len = os_strlen(label);
    494 	data_len = label_len + id_s_len + id_p_len + 2 * sess->nonce_len;
    495 	data = os_malloc(data_len);
    496 	if (data == NULL)
    497 		return -1;
    498 	pos = data;
    499 	os_memcpy(pos, label, label_len);
    500 	pos += label_len;
    501 	os_memcpy(pos, id_s, id_s_len);
    502 	pos += id_s_len;
    503 	os_memcpy(pos, id_p, id_p_len);
    504 	pos += id_p_len;
    505 	os_memcpy(pos, nonce_p, sess->nonce_len);
    506 	pos += sess->nonce_len;
    507 	os_memcpy(pos, nonce_s, sess->nonce_len);
    508 	if (eap_eke_prfplus(sess->prf, sess->shared_secret, sess->prf_len,
    509 			    data, data_len, sess->ka, sess->prf_len) < 0) {
    510 		os_free(data);
    511 		return -1;
    512 	}
    513 	os_free(data);
    514 
    515 	wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: Ka", sess->ka, sess->prf_len);
    516 
    517 	return 0;
    518 }
    519 
    520 
    521 int eap_eke_derive_msk(struct eap_eke_session *sess,
    522 		       const u8 *id_s, size_t id_s_len,
    523 		       const u8 *id_p, size_t id_p_len,
    524 		       const u8 *nonce_p, const u8 *nonce_s,
    525 		       u8 *msk, u8 *emsk)
    526 {
    527 	u8 *data, *pos;
    528 	size_t data_len;
    529 	const char *label = "EAP-EKE Exported Keys";
    530 	size_t label_len;
    531 	u8 buf[EAP_MSK_LEN + EAP_EMSK_LEN];
    532 
    533 	/*
    534 	 * MSK | EMSK = prf+(SharedSecret, "EAP-EKE Exported Keys" | ID_S |
    535 	 *		     ID_P | Nonce_P | Nonce_S)
    536 	 */
    537 
    538 	label_len = os_strlen(label);
    539 	data_len = label_len + id_s_len + id_p_len + 2 * sess->nonce_len;
    540 	data = os_malloc(data_len);
    541 	if (data == NULL)
    542 		return -1;
    543 	pos = data;
    544 	os_memcpy(pos, label, label_len);
    545 	pos += label_len;
    546 	os_memcpy(pos, id_s, id_s_len);
    547 	pos += id_s_len;
    548 	os_memcpy(pos, id_p, id_p_len);
    549 	pos += id_p_len;
    550 	os_memcpy(pos, nonce_p, sess->nonce_len);
    551 	pos += sess->nonce_len;
    552 	os_memcpy(pos, nonce_s, sess->nonce_len);
    553 	if (eap_eke_prfplus(sess->prf, sess->shared_secret, sess->prf_len,
    554 			    data, data_len, buf, EAP_MSK_LEN + EAP_EMSK_LEN) <
    555 	    0) {
    556 		os_free(data);
    557 		return -1;
    558 	}
    559 	os_free(data);
    560 
    561 	os_memcpy(msk, buf, EAP_MSK_LEN);
    562 	os_memcpy(emsk, buf + EAP_MSK_LEN, EAP_EMSK_LEN);
    563 	os_memset(buf, 0, sizeof(buf));
    564 
    565 	wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: MSK", msk, EAP_MSK_LEN);
    566 	wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: EMSK", msk, EAP_EMSK_LEN);
    567 
    568 	return 0;
    569 }
    570 
    571 
    572 static int eap_eke_mac(u8 mac, const u8 *key, const u8 *data, size_t data_len,
    573 		       u8 *res)
    574 {
    575 	if (mac == EAP_EKE_MAC_HMAC_SHA1)
    576 		return hmac_sha1(key, SHA1_MAC_LEN, data, data_len, res);
    577 	if (mac == EAP_EKE_MAC_HMAC_SHA2_256)
    578 		return hmac_sha256(key, SHA256_MAC_LEN, data, data_len, res);
    579 	return -1;
    580 }
    581 
    582 
    583 int eap_eke_prot(struct eap_eke_session *sess,
    584 		 const u8 *data, size_t data_len,
    585 		 u8 *prot, size_t *prot_len)
    586 {
    587 	size_t block_size, icv_len, pad;
    588 	u8 *pos, *iv, *e;
    589 
    590 	if (sess->encr == EAP_EKE_ENCR_AES128_CBC)
    591 		block_size = AES_BLOCK_SIZE;
    592 	else
    593 		return -1;
    594 
    595 	if (sess->mac == EAP_EKE_PRF_HMAC_SHA1)
    596 		icv_len = SHA1_MAC_LEN;
    597 	else if (sess->mac == EAP_EKE_PRF_HMAC_SHA2_256)
    598 		icv_len = SHA256_MAC_LEN;
    599 	else
    600 		return -1;
    601 
    602 	pad = data_len % block_size;
    603 	if (pad)
    604 		pad = block_size - pad;
    605 
    606 	if (*prot_len < block_size + data_len + pad + icv_len) {
    607 		wpa_printf(MSG_INFO, "EAP-EKE: Not enough room for Prot() data");
    608 		return -1;
    609 	}
    610 	pos = prot;
    611 
    612 	if (random_get_bytes(pos, block_size))
    613 		return -1;
    614 	iv = pos;
    615 	wpa_hexdump(MSG_DEBUG, "EAP-EKE: IV for Prot()", iv, block_size);
    616 	pos += block_size;
    617 
    618 	e = pos;
    619 	os_memcpy(pos, data, data_len);
    620 	pos += data_len;
    621 	if (pad) {
    622 		if (random_get_bytes(pos, pad))
    623 			return -1;
    624 		pos += pad;
    625 	}
    626 
    627 	if (aes_128_cbc_encrypt(sess->ke, iv, e, data_len + pad) < 0 ||
    628 	    eap_eke_mac(sess->mac, sess->ki, e, data_len + pad, pos) < 0)
    629 		return -1;
    630 	pos += icv_len;
    631 
    632 	*prot_len = pos - prot;
    633 	return 0;
    634 }
    635 
    636 
    637 int eap_eke_decrypt_prot(struct eap_eke_session *sess,
    638 			 const u8 *prot, size_t prot_len,
    639 			 u8 *data, size_t *data_len)
    640 {
    641 	size_t block_size, icv_len;
    642 	u8 icv[EAP_EKE_MAX_HASH_LEN];
    643 
    644 	if (sess->encr == EAP_EKE_ENCR_AES128_CBC)
    645 		block_size = AES_BLOCK_SIZE;
    646 	else
    647 		return -1;
    648 
    649 	if (sess->mac == EAP_EKE_PRF_HMAC_SHA1)
    650 		icv_len = SHA1_MAC_LEN;
    651 	else if (sess->mac == EAP_EKE_PRF_HMAC_SHA2_256)
    652 		icv_len = SHA256_MAC_LEN;
    653 	else
    654 		return -1;
    655 
    656 	if (prot_len < 2 * block_size + icv_len ||
    657 	    (prot_len - icv_len) % block_size)
    658 		return -1;
    659 
    660 	if (eap_eke_mac(sess->mac, sess->ki, prot + block_size,
    661 			prot_len - block_size - icv_len, icv) < 0)
    662 		return -1;
    663 	if (os_memcmp_const(icv, prot + prot_len - icv_len, icv_len) != 0) {
    664 		wpa_printf(MSG_INFO, "EAP-EKE: ICV mismatch in Prot() data");
    665 		return -1;
    666 	}
    667 
    668 	if (*data_len < prot_len - block_size - icv_len) {
    669 		wpa_printf(MSG_INFO, "EAP-EKE: Not enough room for decrypted Prot() data");
    670 		return -1;
    671 	}
    672 
    673 	*data_len = prot_len - block_size - icv_len;
    674 	os_memcpy(data, prot + block_size, *data_len);
    675 	if (aes_128_cbc_decrypt(sess->ke, prot, data, *data_len) < 0) {
    676 		wpa_printf(MSG_INFO, "EAP-EKE: Failed to decrypt Prot() data");
    677 		return -1;
    678 	}
    679 	wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: Decrypted Prot() data",
    680 			data, *data_len);
    681 
    682 	return 0;
    683 }
    684 
    685 
    686 int eap_eke_auth(struct eap_eke_session *sess, const char *label,
    687 		 const struct wpabuf *msgs, u8 *auth)
    688 {
    689 	wpa_printf(MSG_DEBUG, "EAP-EKE: Auth(%s)", label);
    690 	wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: Ka for Auth",
    691 			sess->ka, sess->auth_len);
    692 	wpa_hexdump_buf(MSG_MSGDUMP, "EAP-EKE: Messages for Auth", msgs);
    693 	return eap_eke_prf(sess->prf, sess->ka, sess->auth_len,
    694 			   (const u8 *) label, os_strlen(label),
    695 			   wpabuf_head(msgs), wpabuf_len(msgs), auth);
    696 }
    697 
    698 
    699 int eap_eke_session_init(struct eap_eke_session *sess, u8 dhgroup, u8 encr,
    700 			 u8 prf, u8 mac)
    701 {
    702 	sess->dhgroup = dhgroup;
    703 	sess->encr = encr;
    704 	sess->prf = prf;
    705 	sess->mac = mac;
    706 
    707 	sess->prf_len = eap_eke_prf_len(prf);
    708 	sess->nonce_len = eap_eke_nonce_len(prf);
    709 	sess->auth_len = eap_eke_auth_len(prf);
    710 	sess->dhcomp_len = eap_eke_dhcomp_len(sess->dhgroup, sess->encr);
    711 	sess->pnonce_len = eap_eke_pnonce_len(sess->mac);
    712 	sess->pnonce_ps_len = eap_eke_pnonce_ps_len(sess->mac);
    713 	if (sess->prf_len < 0 || sess->nonce_len < 0 || sess->auth_len < 0 ||
    714 	    sess->dhcomp_len < 0 || sess->pnonce_len < 0 ||
    715 	    sess->pnonce_ps_len < 0)
    716 		return -1;
    717 
    718 	return 0;
    719 }
    720 
    721 
    722 void eap_eke_session_clean(struct eap_eke_session *sess)
    723 {
    724 	os_memset(sess->shared_secret, 0, EAP_EKE_MAX_HASH_LEN);
    725 	os_memset(sess->ke, 0, EAP_EKE_MAX_KE_LEN);
    726 	os_memset(sess->ki, 0, EAP_EKE_MAX_KI_LEN);
    727 	os_memset(sess->ka, 0, EAP_EKE_MAX_KA_LEN);
    728 }
    729