1 /*
2 * EAP server/peer: EAP-EKE shared routines
3 * Copyright (c) 2011-2013, Jouni Malinen <j@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
eap_eke_dh_len(u8 group)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
eap_eke_dhcomp_len(u8 dhgroup,u8 encr)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)
48 return -1;
49 if (encr != EAP_EKE_ENCR_AES128_CBC)
50 return -1;
51 return AES_BLOCK_SIZE + dhlen;
52 }
53
54
eap_eke_dh_group(u8 group)55 static const struct dh_group * eap_eke_dh_group(u8 group)
56 {
57 switch (group) {
58 case EAP_EKE_DHGROUP_EKE_2:
59 return dh_groups_get(2);
60 case EAP_EKE_DHGROUP_EKE_5:
61 return dh_groups_get(5);
62 case EAP_EKE_DHGROUP_EKE_14:
63 return dh_groups_get(14);
64 case EAP_EKE_DHGROUP_EKE_15:
65 return dh_groups_get(15);
66 case EAP_EKE_DHGROUP_EKE_16:
67 return dh_groups_get(16);
68 }
69
70 return NULL;
71 }
72
73
eap_eke_dh_generator(u8 group)74 static int eap_eke_dh_generator(u8 group)
75 {
76 switch (group) {
77 case EAP_EKE_DHGROUP_EKE_2:
78 return 5;
79 case EAP_EKE_DHGROUP_EKE_5:
80 return 31;
81 case EAP_EKE_DHGROUP_EKE_14:
82 return 11;
83 case EAP_EKE_DHGROUP_EKE_15:
84 return 5;
85 case EAP_EKE_DHGROUP_EKE_16:
86 return 5;
87 }
88
89 return -1;
90 }
91
92
eap_eke_pnonce_len(u8 mac)93 static int eap_eke_pnonce_len(u8 mac)
94 {
95 int mac_len;
96
97 if (mac == EAP_EKE_MAC_HMAC_SHA1)
98 mac_len = SHA1_MAC_LEN;
99 else if (mac == EAP_EKE_MAC_HMAC_SHA2_256)
100 mac_len = SHA256_MAC_LEN;
101 else
102 return -1;
103
104 return AES_BLOCK_SIZE + 16 + mac_len;
105 }
106
107
eap_eke_pnonce_ps_len(u8 mac)108 static int eap_eke_pnonce_ps_len(u8 mac)
109 {
110 int mac_len;
111
112 if (mac == EAP_EKE_MAC_HMAC_SHA1)
113 mac_len = SHA1_MAC_LEN;
114 else if (mac == EAP_EKE_MAC_HMAC_SHA2_256)
115 mac_len = SHA256_MAC_LEN;
116 else
117 return -1;
118
119 return AES_BLOCK_SIZE + 2 * 16 + mac_len;
120 }
121
122
eap_eke_prf_len(u8 prf)123 static int eap_eke_prf_len(u8 prf)
124 {
125 if (prf == EAP_EKE_PRF_HMAC_SHA1)
126 return 20;
127 if (prf == EAP_EKE_PRF_HMAC_SHA2_256)
128 return 32;
129 return -1;
130 }
131
132
eap_eke_nonce_len(u8 prf)133 static int eap_eke_nonce_len(u8 prf)
134 {
135 int prf_len;
136
137 prf_len = eap_eke_prf_len(prf);
138 if (prf_len < 0)
139 return -1;
140
141 if (prf_len > 2 * 16)
142 return (prf_len + 1) / 2;
143
144 return 16;
145 }
146
147
eap_eke_auth_len(u8 prf)148 static int eap_eke_auth_len(u8 prf)
149 {
150 switch (prf) {
151 case EAP_EKE_PRF_HMAC_SHA1:
152 return SHA1_MAC_LEN;
153 case EAP_EKE_PRF_HMAC_SHA2_256:
154 return SHA256_MAC_LEN;
155 }
156
157 return -1;
158 }
159
160
eap_eke_dh_init(u8 group,u8 * ret_priv,u8 * ret_pub)161 int eap_eke_dh_init(u8 group, u8 *ret_priv, u8 *ret_pub)
162 {
163 int generator;
164 u8 gen;
165 const struct dh_group *dh;
166 size_t pub_len, i;
167
168 generator = eap_eke_dh_generator(group);
169 if (generator < 0 || generator > 255)
170 return -1;
171 gen = generator;
172
173 dh = eap_eke_dh_group(group);
174 if (dh == NULL)
175 return -1;
176
177 /* x = random number 2 .. p-1 */
178 if (random_get_bytes(ret_priv, dh->prime_len))
179 return -1;
180 if (os_memcmp(ret_priv, dh->prime, dh->prime_len) > 0) {
181 /* Make sure private value is smaller than prime */
182 ret_priv[0] = 0;
183 }
184 for (i = 0; i < dh->prime_len - 1; i++) {
185 if (ret_priv[i])
186 break;
187 }
188 if (i == dh->prime_len - 1 && (ret_priv[i] == 0 || ret_priv[i] == 1))
189 return -1;
190 wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: DH private value",
191 ret_priv, dh->prime_len);
192
193 /* y = g ^ x (mod p) */
194 pub_len = dh->prime_len;
195 if (crypto_mod_exp(&gen, 1, ret_priv, dh->prime_len,
196 dh->prime, dh->prime_len, ret_pub, &pub_len) < 0)
197 return -1;
198 if (pub_len < dh->prime_len) {
199 size_t pad = dh->prime_len - pub_len;
200 os_memmove(ret_pub + pad, ret_pub, pub_len);
201 os_memset(ret_pub, 0, pad);
202 }
203
204 wpa_hexdump(MSG_DEBUG, "EAP-EKE: DH public value",
205 ret_pub, dh->prime_len);
206
207 return 0;
208 }
209
210
eap_eke_prf(u8 prf,const u8 * key,size_t key_len,const u8 * data,size_t data_len,const u8 * data2,size_t data2_len,u8 * res)211 static int eap_eke_prf(u8 prf, const u8 *key, size_t key_len, const u8 *data,
212 size_t data_len, const u8 *data2, size_t data2_len,
213 u8 *res)
214 {
215 const u8 *addr[2];
216 size_t len[2];
217 size_t num_elem = 1;
218
219 addr[0] = data;
220 len[0] = data_len;
221 if (data2) {
222 num_elem++;
223 addr[1] = data2;
224 len[1] = data2_len;
225 }
226
227 if (prf == EAP_EKE_PRF_HMAC_SHA1)
228 return hmac_sha1_vector(key, key_len, num_elem, addr, len, res);
229 if (prf == EAP_EKE_PRF_HMAC_SHA2_256)
230 return hmac_sha256_vector(key, key_len, num_elem, addr, len,
231 res);
232 return -1;
233 }
234
235
eap_eke_prf_hmac_sha1(const u8 * key,size_t key_len,const u8 * data,size_t data_len,u8 * res,size_t len)236 static int eap_eke_prf_hmac_sha1(const u8 *key, size_t key_len, const u8 *data,
237 size_t data_len, u8 *res, size_t len)
238 {
239 u8 hash[SHA1_MAC_LEN];
240 u8 idx;
241 const u8 *addr[3];
242 size_t vlen[3];
243 int ret;
244
245 idx = 0;
246 addr[0] = hash;
247 vlen[0] = SHA1_MAC_LEN;
248 addr[1] = data;
249 vlen[1] = data_len;
250 addr[2] = &idx;
251 vlen[2] = 1;
252
253 while (len > 0) {
254 idx++;
255 if (idx == 1)
256 ret = hmac_sha1_vector(key, key_len, 2, &addr[1],
257 &vlen[1], hash);
258 else
259 ret = hmac_sha1_vector(key, key_len, 3, addr, vlen,
260 hash);
261 if (ret < 0)
262 return -1;
263 if (len > SHA1_MAC_LEN) {
264 os_memcpy(res, hash, SHA1_MAC_LEN);
265 res += SHA1_MAC_LEN;
266 len -= SHA1_MAC_LEN;
267 } else {
268 os_memcpy(res, hash, len);
269 len = 0;
270 }
271 }
272
273 return 0;
274 }
275
276
eap_eke_prf_hmac_sha256(const u8 * key,size_t key_len,const u8 * data,size_t data_len,u8 * res,size_t len)277 static int eap_eke_prf_hmac_sha256(const u8 *key, size_t key_len, const u8 *data,
278 size_t data_len, u8 *res, size_t len)
279 {
280 u8 hash[SHA256_MAC_LEN];
281 u8 idx;
282 const u8 *addr[3];
283 size_t vlen[3];
284 int ret;
285
286 idx = 0;
287 addr[0] = hash;
288 vlen[0] = SHA256_MAC_LEN;
289 addr[1] = data;
290 vlen[1] = data_len;
291 addr[2] = &idx;
292 vlen[2] = 1;
293
294 while (len > 0) {
295 idx++;
296 if (idx == 1)
297 ret = hmac_sha256_vector(key, key_len, 2, &addr[1],
298 &vlen[1], hash);
299 else
300 ret = hmac_sha256_vector(key, key_len, 3, addr, vlen,
301 hash);
302 if (ret < 0)
303 return -1;
304 if (len > SHA256_MAC_LEN) {
305 os_memcpy(res, hash, SHA256_MAC_LEN);
306 res += SHA256_MAC_LEN;
307 len -= SHA256_MAC_LEN;
308 } else {
309 os_memcpy(res, hash, len);
310 len = 0;
311 }
312 }
313
314 return 0;
315 }
316
317
eap_eke_prfplus(u8 prf,const u8 * key,size_t key_len,const u8 * data,size_t data_len,u8 * res,size_t len)318 static int eap_eke_prfplus(u8 prf, const u8 *key, size_t key_len,
319 const u8 *data, size_t data_len, u8 *res, size_t len)
320 {
321 if (prf == EAP_EKE_PRF_HMAC_SHA1)
322 return eap_eke_prf_hmac_sha1(key, key_len, data, data_len, res,
323 len);
324 if (prf == EAP_EKE_PRF_HMAC_SHA2_256)
325 return eap_eke_prf_hmac_sha256(key, key_len, data, data_len,
326 res, len);
327 return -1;
328 }
329
330
eap_eke_derive_key(struct eap_eke_session * sess,const u8 * password,size_t password_len,const u8 * id_s,size_t id_s_len,const u8 * id_p,size_t id_p_len,u8 * key)331 int eap_eke_derive_key(struct eap_eke_session *sess,
332 const u8 *password, size_t password_len,
333 const u8 *id_s, size_t id_s_len, const u8 *id_p,
334 size_t id_p_len, u8 *key)
335 {
336 u8 zeros[EAP_EKE_MAX_HASH_LEN];
337 u8 temp[EAP_EKE_MAX_HASH_LEN];
338 size_t key_len = 16; /* Only AES-128-CBC is used here */
339 u8 *id;
340
341 /* temp = prf(0+, password) */
342 os_memset(zeros, 0, sess->prf_len);
343 if (eap_eke_prf(sess->prf, zeros, sess->prf_len,
344 password, password_len, NULL, 0, temp) < 0)
345 return -1;
346 wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: temp = prf(0+, password)",
347 temp, sess->prf_len);
348
349 /* key = prf+(temp, ID_S | ID_P) */
350 id = os_malloc(id_s_len + id_p_len);
351 if (id == NULL)
352 return -1;
353 os_memcpy(id, id_s, id_s_len);
354 os_memcpy(id + id_s_len, id_p, id_p_len);
355 wpa_hexdump_ascii(MSG_DEBUG, "EAP-EKE: ID_S | ID_P",
356 id, id_s_len + id_p_len);
357 if (eap_eke_prfplus(sess->prf, temp, sess->prf_len,
358 id, id_s_len + id_p_len, key, key_len) < 0) {
359 os_free(id);
360 return -1;
361 }
362 os_free(id);
363 wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: key = prf+(temp, ID_S | ID_P)",
364 key, key_len);
365
366 return 0;
367 }
368
369
eap_eke_dhcomp(struct eap_eke_session * sess,const u8 * key,const u8 * dhpub,u8 * ret_dhcomp)370 int eap_eke_dhcomp(struct eap_eke_session *sess, const u8 *key, const u8 *dhpub,
371 u8 *ret_dhcomp)
372 {
373 u8 pub[EAP_EKE_MAX_DH_LEN];
374 int dh_len;
375 u8 iv[AES_BLOCK_SIZE];
376
377 dh_len = eap_eke_dh_len(sess->dhgroup);
378 if (dh_len < 0)
379 return -1;
380
381 /*
382 * DHComponent = Encr(key, y)
383 *
384 * All defined DH groups use primes that have length devisible by 16, so
385 * no need to do extra padding for y (= pub).
386 */
387 if (sess->encr != EAP_EKE_ENCR_AES128_CBC)
388 return -1;
389 if (random_get_bytes(iv, AES_BLOCK_SIZE))
390 return -1;
391 wpa_hexdump(MSG_DEBUG, "EAP-EKE: IV for Encr(key, y)",
392 iv, AES_BLOCK_SIZE);
393 os_memcpy(pub, dhpub, dh_len);
394 if (aes_128_cbc_encrypt(key, iv, pub, dh_len) < 0)
395 return -1;
396 os_memcpy(ret_dhcomp, iv, AES_BLOCK_SIZE);
397 os_memcpy(ret_dhcomp + AES_BLOCK_SIZE, pub, dh_len);
398 wpa_hexdump(MSG_DEBUG, "EAP-EKE: DHComponent = Encr(key, y)",
399 ret_dhcomp, AES_BLOCK_SIZE + dh_len);
400
401 return 0;
402 }
403
404
eap_eke_shared_secret(struct eap_eke_session * sess,const u8 * key,const u8 * dhpriv,const u8 * peer_dhcomp)405 int eap_eke_shared_secret(struct eap_eke_session *sess, const u8 *key,
406 const u8 *dhpriv, const u8 *peer_dhcomp)
407 {
408 u8 zeros[EAP_EKE_MAX_HASH_LEN];
409 u8 peer_pub[EAP_EKE_MAX_DH_LEN];
410 u8 modexp[EAP_EKE_MAX_DH_LEN];
411 size_t len;
412 const struct dh_group *dh;
413
414 if (sess->encr != EAP_EKE_ENCR_AES128_CBC)
415 return -1;
416
417 dh = eap_eke_dh_group(sess->dhgroup);
418 if (dh == NULL)
419 return -1;
420
421 /* Decrypt peer DHComponent */
422 os_memcpy(peer_pub, peer_dhcomp + AES_BLOCK_SIZE, dh->prime_len);
423 if (aes_128_cbc_decrypt(key, peer_dhcomp, peer_pub, dh->prime_len) < 0) {
424 wpa_printf(MSG_INFO, "EAP-EKE: Failed to decrypt DHComponent");
425 return -1;
426 }
427 wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: Decrypted peer DH pubkey",
428 peer_pub, dh->prime_len);
429
430 /* SharedSecret = prf(0+, g ^ (x_s * x_p) (mod p)) */
431 len = dh->prime_len;
432 if (crypto_mod_exp(peer_pub, dh->prime_len, dhpriv, dh->prime_len,
433 dh->prime, dh->prime_len, modexp, &len) < 0)
434 return -1;
435 if (len < dh->prime_len) {
436 size_t pad = dh->prime_len - len;
437 os_memmove(modexp + pad, modexp, len);
438 os_memset(modexp, 0, pad);
439 }
440
441 os_memset(zeros, 0, sess->auth_len);
442 if (eap_eke_prf(sess->prf, zeros, sess->auth_len, modexp, dh->prime_len,
443 NULL, 0, sess->shared_secret) < 0)
444 return -1;
445 wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: SharedSecret",
446 sess->shared_secret, sess->auth_len);
447
448 return 0;
449 }
450
451
eap_eke_derive_ke_ki(struct eap_eke_session * sess,const u8 * id_s,size_t id_s_len,const u8 * id_p,size_t id_p_len)452 int eap_eke_derive_ke_ki(struct eap_eke_session *sess,
453 const u8 *id_s, size_t id_s_len,
454 const u8 *id_p, size_t id_p_len)
455 {
456 u8 buf[EAP_EKE_MAX_KE_LEN + EAP_EKE_MAX_KI_LEN];
457 size_t ke_len, ki_len;
458 u8 *data;
459 size_t data_len;
460 const char *label = "EAP-EKE Keys";
461 size_t label_len;
462
463 /*
464 * Ke | Ki = prf+(SharedSecret, "EAP-EKE Keys" | ID_S | ID_P)
465 * Ke = encryption key
466 * Ki = integrity protection key
467 * Length of each key depends on the selected algorithms.
468 */
469
470 if (sess->encr == EAP_EKE_ENCR_AES128_CBC)
471 ke_len = 16;
472 else
473 return -1;
474
475 if (sess->mac == EAP_EKE_PRF_HMAC_SHA1)
476 ki_len = 20;
477 else if (sess->mac == EAP_EKE_PRF_HMAC_SHA2_256)
478 ki_len = 32;
479 else
480 return -1;
481
482 label_len = os_strlen(label);
483 data_len = label_len + id_s_len + id_p_len;
484 data = os_malloc(data_len);
485 if (data == NULL)
486 return -1;
487 os_memcpy(data, label, label_len);
488 os_memcpy(data + label_len, id_s, id_s_len);
489 os_memcpy(data + label_len + id_s_len, id_p, id_p_len);
490 if (eap_eke_prfplus(sess->prf, sess->shared_secret, sess->prf_len,
491 data, data_len, buf, ke_len + ki_len) < 0) {
492 os_free(data);
493 return -1;
494 }
495
496 os_memcpy(sess->ke, buf, ke_len);
497 wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: Ke", sess->ke, ke_len);
498 os_memcpy(sess->ki, buf + ke_len, ki_len);
499 wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: Ki", sess->ki, ki_len);
500
501 os_free(data);
502 return 0;
503 }
504
505
eap_eke_derive_ka(struct eap_eke_session * sess,const u8 * id_s,size_t id_s_len,const u8 * id_p,size_t id_p_len,const u8 * nonce_p,const u8 * nonce_s)506 int eap_eke_derive_ka(struct eap_eke_session *sess,
507 const u8 *id_s, size_t id_s_len,
508 const u8 *id_p, size_t id_p_len,
509 const u8 *nonce_p, const u8 *nonce_s)
510 {
511 u8 *data, *pos;
512 size_t data_len;
513 const char *label = "EAP-EKE Ka";
514 size_t label_len;
515
516 /*
517 * Ka = prf+(SharedSecret, "EAP-EKE Ka" | ID_S | ID_P | Nonce_P |
518 * Nonce_S)
519 * Ka = authentication key
520 * Length of the key depends on the selected algorithms.
521 */
522
523 label_len = os_strlen(label);
524 data_len = label_len + id_s_len + id_p_len + 2 * sess->nonce_len;
525 data = os_malloc(data_len);
526 if (data == NULL)
527 return -1;
528 pos = data;
529 os_memcpy(pos, label, label_len);
530 pos += label_len;
531 os_memcpy(pos, id_s, id_s_len);
532 pos += id_s_len;
533 os_memcpy(pos, id_p, id_p_len);
534 pos += id_p_len;
535 os_memcpy(pos, nonce_p, sess->nonce_len);
536 pos += sess->nonce_len;
537 os_memcpy(pos, nonce_s, sess->nonce_len);
538 if (eap_eke_prfplus(sess->prf, sess->shared_secret, sess->prf_len,
539 data, data_len, sess->ka, sess->prf_len) < 0) {
540 os_free(data);
541 return -1;
542 }
543 os_free(data);
544
545 wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: Ka", sess->ka, sess->prf_len);
546
547 return 0;
548 }
549
550
eap_eke_derive_msk(struct eap_eke_session * sess,const u8 * id_s,size_t id_s_len,const u8 * id_p,size_t id_p_len,const u8 * nonce_p,const u8 * nonce_s,u8 * msk,u8 * emsk)551 int eap_eke_derive_msk(struct eap_eke_session *sess,
552 const u8 *id_s, size_t id_s_len,
553 const u8 *id_p, size_t id_p_len,
554 const u8 *nonce_p, const u8 *nonce_s,
555 u8 *msk, u8 *emsk)
556 {
557 u8 *data, *pos;
558 size_t data_len;
559 const char *label = "EAP-EKE Exported Keys";
560 size_t label_len;
561 u8 buf[EAP_MSK_LEN + EAP_EMSK_LEN];
562
563 /*
564 * MSK | EMSK = prf+(SharedSecret, "EAP-EKE Exported Keys" | ID_S |
565 * ID_P | Nonce_P | Nonce_S)
566 */
567
568 label_len = os_strlen(label);
569 data_len = label_len + id_s_len + id_p_len + 2 * sess->nonce_len;
570 data = os_malloc(data_len);
571 if (data == NULL)
572 return -1;
573 pos = data;
574 os_memcpy(pos, label, label_len);
575 pos += label_len;
576 os_memcpy(pos, id_s, id_s_len);
577 pos += id_s_len;
578 os_memcpy(pos, id_p, id_p_len);
579 pos += id_p_len;
580 os_memcpy(pos, nonce_p, sess->nonce_len);
581 pos += sess->nonce_len;
582 os_memcpy(pos, nonce_s, sess->nonce_len);
583 if (eap_eke_prfplus(sess->prf, sess->shared_secret, sess->prf_len,
584 data, data_len, buf, EAP_MSK_LEN + EAP_EMSK_LEN) <
585 0) {
586 os_free(data);
587 return -1;
588 }
589 os_free(data);
590
591 os_memcpy(msk, buf, EAP_MSK_LEN);
592 os_memcpy(emsk, buf + EAP_MSK_LEN, EAP_EMSK_LEN);
593 os_memset(buf, 0, sizeof(buf));
594
595 wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: MSK", msk, EAP_MSK_LEN);
596 wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: EMSK", msk, EAP_EMSK_LEN);
597
598 return 0;
599 }
600
601
eap_eke_mac(u8 mac,const u8 * key,const u8 * data,size_t data_len,u8 * res)602 static int eap_eke_mac(u8 mac, const u8 *key, const u8 *data, size_t data_len,
603 u8 *res)
604 {
605 if (mac == EAP_EKE_MAC_HMAC_SHA1)
606 return hmac_sha1(key, SHA1_MAC_LEN, data, data_len, res);
607 if (mac == EAP_EKE_MAC_HMAC_SHA2_256)
608 return hmac_sha256(key, SHA256_MAC_LEN, data, data_len, res);
609 return -1;
610 }
611
612
eap_eke_prot(struct eap_eke_session * sess,const u8 * data,size_t data_len,u8 * prot,size_t * prot_len)613 int eap_eke_prot(struct eap_eke_session *sess,
614 const u8 *data, size_t data_len,
615 u8 *prot, size_t *prot_len)
616 {
617 size_t block_size, icv_len, pad;
618 u8 *pos, *iv, *e;
619
620 if (sess->encr == EAP_EKE_ENCR_AES128_CBC)
621 block_size = AES_BLOCK_SIZE;
622 else
623 return -1;
624
625 if (sess->mac == EAP_EKE_PRF_HMAC_SHA1)
626 icv_len = SHA1_MAC_LEN;
627 else if (sess->mac == EAP_EKE_PRF_HMAC_SHA2_256)
628 icv_len = SHA256_MAC_LEN;
629 else
630 return -1;
631
632 pad = data_len % block_size;
633 if (pad)
634 pad = block_size - pad;
635
636 if (*prot_len < block_size + data_len + pad + icv_len) {
637 wpa_printf(MSG_INFO, "EAP-EKE: Not enough room for Prot() data");
638 }
639 pos = prot;
640
641 if (random_get_bytes(pos, block_size))
642 return -1;
643 iv = pos;
644 wpa_hexdump(MSG_DEBUG, "EAP-EKE: IV for Prot()", iv, block_size);
645 pos += block_size;
646
647 e = pos;
648 os_memcpy(pos, data, data_len);
649 pos += data_len;
650 if (pad) {
651 if (random_get_bytes(pos, pad))
652 return -1;
653 pos += pad;
654 }
655
656 if (aes_128_cbc_encrypt(sess->ke, iv, e, data_len + pad) < 0)
657 return -1;
658
659 if (eap_eke_mac(sess->mac, sess->ki, e, data_len + pad, pos) < 0)
660 return -1;
661 pos += icv_len;
662
663 *prot_len = pos - prot;
664 return 0;
665 }
666
667
eap_eke_decrypt_prot(struct eap_eke_session * sess,const u8 * prot,size_t prot_len,u8 * data,size_t * data_len)668 int eap_eke_decrypt_prot(struct eap_eke_session *sess,
669 const u8 *prot, size_t prot_len,
670 u8 *data, size_t *data_len)
671 {
672 size_t block_size, icv_len;
673 u8 icv[EAP_EKE_MAX_HASH_LEN];
674
675 if (sess->encr == EAP_EKE_ENCR_AES128_CBC)
676 block_size = AES_BLOCK_SIZE;
677 else
678 return -1;
679
680 if (sess->mac == EAP_EKE_PRF_HMAC_SHA1)
681 icv_len = SHA1_MAC_LEN;
682 else if (sess->mac == EAP_EKE_PRF_HMAC_SHA2_256)
683 icv_len = SHA256_MAC_LEN;
684 else
685 return -1;
686
687 if (prot_len < 2 * block_size + icv_len)
688 return -1;
689 if ((prot_len - icv_len) % block_size)
690 return -1;
691
692 if (eap_eke_mac(sess->mac, sess->ki, prot + block_size,
693 prot_len - block_size - icv_len, icv) < 0)
694 return -1;
695 if (os_memcmp_const(icv, prot + prot_len - icv_len, icv_len) != 0) {
696 wpa_printf(MSG_INFO, "EAP-EKE: ICV mismatch in Prot() data");
697 return -1;
698 }
699
700 if (*data_len < prot_len - block_size - icv_len) {
701 wpa_printf(MSG_INFO, "EAP-EKE: Not enough room for decrypted Prot() data");
702 return -1;
703 }
704
705 *data_len = prot_len - block_size - icv_len;
706 os_memcpy(data, prot + block_size, *data_len);
707 if (aes_128_cbc_decrypt(sess->ke, prot, data, *data_len) < 0) {
708 wpa_printf(MSG_INFO, "EAP-EKE: Failed to decrypt Prot() data");
709 return -1;
710 }
711 wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: Decrypted Prot() data",
712 data, *data_len);
713
714 return 0;
715 }
716
717
eap_eke_auth(struct eap_eke_session * sess,const char * label,const struct wpabuf * msgs,u8 * auth)718 int eap_eke_auth(struct eap_eke_session *sess, const char *label,
719 const struct wpabuf *msgs, u8 *auth)
720 {
721 wpa_printf(MSG_DEBUG, "EAP-EKE: Auth(%s)", label);
722 wpa_hexdump_key(MSG_DEBUG, "EAP-EKE: Ka for Auth",
723 sess->ka, sess->auth_len);
724 wpa_hexdump_buf(MSG_MSGDUMP, "EAP-EKE: Messages for Auth", msgs);
725 return eap_eke_prf(sess->prf, sess->ka, sess->auth_len,
726 (const u8 *) label, os_strlen(label),
727 wpabuf_head(msgs), wpabuf_len(msgs), auth);
728 }
729
730
eap_eke_session_init(struct eap_eke_session * sess,u8 dhgroup,u8 encr,u8 prf,u8 mac)731 int eap_eke_session_init(struct eap_eke_session *sess, u8 dhgroup, u8 encr,
732 u8 prf, u8 mac)
733 {
734 sess->dhgroup = dhgroup;
735 sess->encr = encr;
736 sess->prf = prf;
737 sess->mac = mac;
738
739 sess->prf_len = eap_eke_prf_len(prf);
740 if (sess->prf_len < 0)
741 return -1;
742 sess->nonce_len = eap_eke_nonce_len(prf);
743 if (sess->nonce_len < 0)
744 return -1;
745 sess->auth_len = eap_eke_auth_len(prf);
746 if (sess->auth_len < 0)
747 return -1;
748 sess->dhcomp_len = eap_eke_dhcomp_len(sess->dhgroup, sess->encr);
749 if (sess->dhcomp_len < 0)
750 return -1;
751 sess->pnonce_len = eap_eke_pnonce_len(sess->mac);
752 if (sess->pnonce_len < 0)
753 return -1;
754 sess->pnonce_ps_len = eap_eke_pnonce_ps_len(sess->mac);
755 if (sess->pnonce_ps_len < 0)
756 return -1;
757
758 return 0;
759 }
760
761
eap_eke_session_clean(struct eap_eke_session * sess)762 void eap_eke_session_clean(struct eap_eke_session *sess)
763 {
764 os_memset(sess->shared_secret, 0, EAP_EKE_MAX_HASH_LEN);
765 os_memset(sess->ke, 0, EAP_EKE_MAX_KE_LEN);
766 os_memset(sess->ki, 0, EAP_EKE_MAX_KI_LEN);
767 os_memset(sess->ka, 0, EAP_EKE_MAX_KA_LEN);
768 }
769