eap_server_pax.c revision 214734
1/* 2 * hostapd / EAP-PAX (RFC 4746) server 3 * Copyright (c) 2005-2007, Jouni Malinen <j@w1.fi> 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License version 2 as 7 * published by the Free Software Foundation. 8 * 9 * Alternatively, this software may be distributed under the terms of BSD 10 * license. 11 * 12 * See README and COPYING for more details. 13 */ 14 15#include "includes.h" 16 17#include "common.h" 18#include "eap_server/eap_i.h" 19#include "eap_common/eap_pax_common.h" 20 21/* 22 * Note: only PAX_STD subprotocol is currently supported 23 * 24 * TODO: Add support with PAX_SEC with the mandatory to implement ciphersuite 25 * (HMAC_SHA1_128, IANA DH Group 14 (2048 bits), RSA-PKCS1-V1_5) and 26 * recommended ciphersuite (HMAC_SHA256_128, IANA DH Group 15 (3072 bits), 27 * RSAES-OAEP). 28 */ 29 30struct eap_pax_data { 31 enum { PAX_STD_1, PAX_STD_3, SUCCESS, FAILURE } state; 32 u8 mac_id; 33 union { 34 u8 e[2 * EAP_PAX_RAND_LEN]; 35 struct { 36 u8 x[EAP_PAX_RAND_LEN]; /* server rand */ 37 u8 y[EAP_PAX_RAND_LEN]; /* client rand */ 38 } r; 39 } rand; 40 u8 ak[EAP_PAX_AK_LEN]; 41 u8 mk[EAP_PAX_MK_LEN]; 42 u8 ck[EAP_PAX_CK_LEN]; 43 u8 ick[EAP_PAX_ICK_LEN]; 44 int keys_set; 45 char *cid; 46 size_t cid_len; 47}; 48 49 50static void * eap_pax_init(struct eap_sm *sm) 51{ 52 struct eap_pax_data *data; 53 54 data = os_zalloc(sizeof(*data)); 55 if (data == NULL) 56 return NULL; 57 data->state = PAX_STD_1; 58 /* 59 * TODO: make this configurable once EAP_PAX_HMAC_SHA256_128 is 60 * supported 61 */ 62 data->mac_id = EAP_PAX_MAC_HMAC_SHA1_128; 63 64 return data; 65} 66 67 68static void eap_pax_reset(struct eap_sm *sm, void *priv) 69{ 70 struct eap_pax_data *data = priv; 71 os_free(data->cid); 72 os_free(data); 73} 74 75 76static struct wpabuf * eap_pax_build_std_1(struct eap_sm *sm, 77 struct eap_pax_data *data, u8 id) 78{ 79 struct wpabuf *req; 80 struct eap_pax_hdr *pax; 81 u8 *pos; 82 83 wpa_printf(MSG_DEBUG, "EAP-PAX: PAX_STD-1 (sending)"); 84 85 if (os_get_random(data->rand.r.x, EAP_PAX_RAND_LEN)) { 86 wpa_printf(MSG_ERROR, "EAP-PAX: Failed to get random data"); 87 data->state = FAILURE; 88 return NULL; 89 } 90 91 req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PAX, 92 sizeof(*pax) + 2 + EAP_PAX_RAND_LEN + 93 EAP_PAX_ICV_LEN, EAP_CODE_REQUEST, id); 94 if (req == NULL) { 95 wpa_printf(MSG_ERROR, "EAP-PAX: Failed to allocate memory " 96 "request"); 97 data->state = FAILURE; 98 return NULL; 99 } 100 101 pax = wpabuf_put(req, sizeof(*pax)); 102 pax->op_code = EAP_PAX_OP_STD_1; 103 pax->flags = 0; 104 pax->mac_id = data->mac_id; 105 pax->dh_group_id = EAP_PAX_DH_GROUP_NONE; 106 pax->public_key_id = EAP_PAX_PUBLIC_KEY_NONE; 107 108 wpabuf_put_be16(req, EAP_PAX_RAND_LEN); 109 wpabuf_put_data(req, data->rand.r.x, EAP_PAX_RAND_LEN); 110 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: A = X (server rand)", 111 data->rand.r.x, EAP_PAX_RAND_LEN); 112 113 pos = wpabuf_put(req, EAP_PAX_MAC_LEN); 114 eap_pax_mac(data->mac_id, (u8 *) "", 0, 115 wpabuf_mhead(req), wpabuf_len(req) - EAP_PAX_ICV_LEN, 116 NULL, 0, NULL, 0, pos); 117 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", pos, EAP_PAX_ICV_LEN); 118 119 return req; 120} 121 122 123static struct wpabuf * eap_pax_build_std_3(struct eap_sm *sm, 124 struct eap_pax_data *data, u8 id) 125{ 126 struct wpabuf *req; 127 struct eap_pax_hdr *pax; 128 u8 *pos; 129 130 wpa_printf(MSG_DEBUG, "EAP-PAX: PAX_STD-3 (sending)"); 131 132 req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PAX, 133 sizeof(*pax) + 2 + EAP_PAX_MAC_LEN + 134 EAP_PAX_ICV_LEN, EAP_CODE_REQUEST, id); 135 if (req == NULL) { 136 wpa_printf(MSG_ERROR, "EAP-PAX: Failed to allocate memory " 137 "request"); 138 data->state = FAILURE; 139 return NULL; 140 } 141 142 pax = wpabuf_put(req, sizeof(*pax)); 143 pax->op_code = EAP_PAX_OP_STD_3; 144 pax->flags = 0; 145 pax->mac_id = data->mac_id; 146 pax->dh_group_id = EAP_PAX_DH_GROUP_NONE; 147 pax->public_key_id = EAP_PAX_PUBLIC_KEY_NONE; 148 149 wpabuf_put_be16(req, EAP_PAX_MAC_LEN); 150 pos = wpabuf_put(req, EAP_PAX_MAC_LEN); 151 eap_pax_mac(data->mac_id, data->ck, EAP_PAX_CK_LEN, 152 data->rand.r.y, EAP_PAX_RAND_LEN, 153 (u8 *) data->cid, data->cid_len, NULL, 0, pos); 154 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: MAC_CK(B, CID)", 155 pos, EAP_PAX_MAC_LEN); 156 pos += EAP_PAX_MAC_LEN; 157 158 /* Optional ADE could be added here, if needed */ 159 160 pos = wpabuf_put(req, EAP_PAX_MAC_LEN); 161 eap_pax_mac(data->mac_id, data->ick, EAP_PAX_ICK_LEN, 162 wpabuf_mhead(req), wpabuf_len(req) - EAP_PAX_ICV_LEN, 163 NULL, 0, NULL, 0, pos); 164 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", pos, EAP_PAX_ICV_LEN); 165 166 return req; 167} 168 169 170static struct wpabuf * eap_pax_buildReq(struct eap_sm *sm, void *priv, u8 id) 171{ 172 struct eap_pax_data *data = priv; 173 174 switch (data->state) { 175 case PAX_STD_1: 176 return eap_pax_build_std_1(sm, data, id); 177 case PAX_STD_3: 178 return eap_pax_build_std_3(sm, data, id); 179 default: 180 wpa_printf(MSG_DEBUG, "EAP-PAX: Unknown state %d in buildReq", 181 data->state); 182 break; 183 } 184 return NULL; 185} 186 187 188static Boolean eap_pax_check(struct eap_sm *sm, void *priv, 189 struct wpabuf *respData) 190{ 191 struct eap_pax_data *data = priv; 192 struct eap_pax_hdr *resp; 193 const u8 *pos; 194 size_t len, mlen; 195 u8 icvbuf[EAP_PAX_ICV_LEN], *icv; 196 197 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PAX, respData, &len); 198 if (pos == NULL || len < sizeof(*resp)) { 199 wpa_printf(MSG_INFO, "EAP-PAX: Invalid frame"); 200 return TRUE; 201 } 202 203 mlen = sizeof(struct eap_hdr) + 1 + len; 204 resp = (struct eap_pax_hdr *) pos; 205 206 wpa_printf(MSG_DEBUG, "EAP-PAX: received frame: op_code 0x%x " 207 "flags 0x%x mac_id 0x%x dh_group_id 0x%x " 208 "public_key_id 0x%x", 209 resp->op_code, resp->flags, resp->mac_id, resp->dh_group_id, 210 resp->public_key_id); 211 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: received payload", 212 (u8 *) (resp + 1), len - sizeof(*resp) - EAP_PAX_ICV_LEN); 213 214 if (data->state == PAX_STD_1 && 215 resp->op_code != EAP_PAX_OP_STD_2) { 216 wpa_printf(MSG_DEBUG, "EAP-PAX: Expected PAX_STD-2 - " 217 "ignore op %d", resp->op_code); 218 return TRUE; 219 } 220 221 if (data->state == PAX_STD_3 && 222 resp->op_code != EAP_PAX_OP_ACK) { 223 wpa_printf(MSG_DEBUG, "EAP-PAX: Expected PAX-ACK - " 224 "ignore op %d", resp->op_code); 225 return TRUE; 226 } 227 228 if (resp->op_code != EAP_PAX_OP_STD_2 && 229 resp->op_code != EAP_PAX_OP_ACK) { 230 wpa_printf(MSG_DEBUG, "EAP-PAX: Unknown op_code 0x%x", 231 resp->op_code); 232 } 233 234 if (data->mac_id != resp->mac_id) { 235 wpa_printf(MSG_DEBUG, "EAP-PAX: Expected MAC ID 0x%x, " 236 "received 0x%x", data->mac_id, resp->mac_id); 237 return TRUE; 238 } 239 240 if (resp->dh_group_id != EAP_PAX_DH_GROUP_NONE) { 241 wpa_printf(MSG_INFO, "EAP-PAX: Expected DH Group ID 0x%x, " 242 "received 0x%x", EAP_PAX_DH_GROUP_NONE, 243 resp->dh_group_id); 244 return TRUE; 245 } 246 247 if (resp->public_key_id != EAP_PAX_PUBLIC_KEY_NONE) { 248 wpa_printf(MSG_INFO, "EAP-PAX: Expected Public Key ID 0x%x, " 249 "received 0x%x", EAP_PAX_PUBLIC_KEY_NONE, 250 resp->public_key_id); 251 return TRUE; 252 } 253 254 if (resp->flags & EAP_PAX_FLAGS_MF) { 255 /* TODO: add support for reassembling fragments */ 256 wpa_printf(MSG_INFO, "EAP-PAX: fragmentation not supported"); 257 return TRUE; 258 } 259 260 if (resp->flags & EAP_PAX_FLAGS_CE) { 261 wpa_printf(MSG_INFO, "EAP-PAX: Unexpected CE flag"); 262 return TRUE; 263 } 264 265 if (data->keys_set) { 266 if (len - sizeof(*resp) < EAP_PAX_ICV_LEN) { 267 wpa_printf(MSG_INFO, "EAP-PAX: No ICV in the packet"); 268 return TRUE; 269 } 270 icv = wpabuf_mhead_u8(respData) + mlen - EAP_PAX_ICV_LEN; 271 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", icv, EAP_PAX_ICV_LEN); 272 eap_pax_mac(data->mac_id, data->ick, EAP_PAX_ICK_LEN, 273 wpabuf_mhead(respData), 274 wpabuf_len(respData) - EAP_PAX_ICV_LEN, 275 NULL, 0, NULL, 0, icvbuf); 276 if (os_memcmp(icvbuf, icv, EAP_PAX_ICV_LEN) != 0) { 277 wpa_printf(MSG_INFO, "EAP-PAX: Invalid ICV"); 278 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: Expected ICV", 279 icvbuf, EAP_PAX_ICV_LEN); 280 return TRUE; 281 } 282 } 283 284 return FALSE; 285} 286 287 288static void eap_pax_process_std_2(struct eap_sm *sm, 289 struct eap_pax_data *data, 290 struct wpabuf *respData) 291{ 292 struct eap_pax_hdr *resp; 293 u8 mac[EAP_PAX_MAC_LEN], icvbuf[EAP_PAX_ICV_LEN]; 294 const u8 *pos; 295 size_t len, left; 296 int i; 297 298 if (data->state != PAX_STD_1) 299 return; 300 301 wpa_printf(MSG_DEBUG, "EAP-PAX: Received PAX_STD-2"); 302 303 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PAX, respData, &len); 304 if (pos == NULL || len < sizeof(*resp) + EAP_PAX_ICV_LEN) 305 return; 306 307 resp = (struct eap_pax_hdr *) pos; 308 pos = (u8 *) (resp + 1); 309 left = len - sizeof(*resp); 310 311 if (left < 2 + EAP_PAX_RAND_LEN || 312 WPA_GET_BE16(pos) != EAP_PAX_RAND_LEN) { 313 wpa_printf(MSG_INFO, "EAP-PAX: Too short PAX_STD-2 (B)"); 314 return; 315 } 316 pos += 2; 317 left -= 2; 318 os_memcpy(data->rand.r.y, pos, EAP_PAX_RAND_LEN); 319 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: Y (client rand)", 320 data->rand.r.y, EAP_PAX_RAND_LEN); 321 pos += EAP_PAX_RAND_LEN; 322 left -= EAP_PAX_RAND_LEN; 323 324 if (left < 2 || (size_t) 2 + WPA_GET_BE16(pos) > left) { 325 wpa_printf(MSG_INFO, "EAP-PAX: Too short PAX_STD-2 (CID)"); 326 return; 327 } 328 data->cid_len = WPA_GET_BE16(pos); 329 os_free(data->cid); 330 data->cid = os_malloc(data->cid_len); 331 if (data->cid == NULL) { 332 wpa_printf(MSG_INFO, "EAP-PAX: Failed to allocate memory for " 333 "CID"); 334 return; 335 } 336 os_memcpy(data->cid, pos + 2, data->cid_len); 337 pos += 2 + data->cid_len; 338 left -= 2 + data->cid_len; 339 wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-PAX: CID", 340 (u8 *) data->cid, data->cid_len); 341 342 if (left < 2 + EAP_PAX_MAC_LEN || 343 WPA_GET_BE16(pos) != EAP_PAX_MAC_LEN) { 344 wpa_printf(MSG_INFO, "EAP-PAX: Too short PAX_STD-2 (MAC_CK)"); 345 return; 346 } 347 pos += 2; 348 left -= 2; 349 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: MAC_CK(A, B, CID)", 350 pos, EAP_PAX_MAC_LEN); 351 352 if (eap_user_get(sm, (u8 *) data->cid, data->cid_len, 0) < 0) { 353 wpa_hexdump_ascii(MSG_DEBUG, "EAP-PAX: unknown CID", 354 (u8 *) data->cid, data->cid_len); 355 data->state = FAILURE; 356 return; 357 } 358 359 for (i = 0; 360 i < EAP_MAX_METHODS && 361 (sm->user->methods[i].vendor != EAP_VENDOR_IETF || 362 sm->user->methods[i].method != EAP_TYPE_NONE); 363 i++) { 364 if (sm->user->methods[i].vendor == EAP_VENDOR_IETF && 365 sm->user->methods[i].method == EAP_TYPE_PAX) 366 break; 367 } 368 369 if (i >= EAP_MAX_METHODS || 370 sm->user->methods[i].vendor != EAP_VENDOR_IETF || 371 sm->user->methods[i].method != EAP_TYPE_PAX) { 372 wpa_hexdump_ascii(MSG_DEBUG, 373 "EAP-PAX: EAP-PAX not enabled for CID", 374 (u8 *) data->cid, data->cid_len); 375 data->state = FAILURE; 376 return; 377 } 378 379 if (sm->user->password == NULL || 380 sm->user->password_len != EAP_PAX_AK_LEN) { 381 wpa_hexdump_ascii(MSG_DEBUG, "EAP-PAX: invalid password in " 382 "user database for CID", 383 (u8 *) data->cid, data->cid_len); 384 data->state = FAILURE; 385 return; 386 } 387 os_memcpy(data->ak, sm->user->password, EAP_PAX_AK_LEN); 388 389 if (eap_pax_initial_key_derivation(data->mac_id, data->ak, 390 data->rand.e, data->mk, data->ck, 391 data->ick) < 0) { 392 wpa_printf(MSG_INFO, "EAP-PAX: Failed to complete initial " 393 "key derivation"); 394 data->state = FAILURE; 395 return; 396 } 397 data->keys_set = 1; 398 399 eap_pax_mac(data->mac_id, data->ck, EAP_PAX_CK_LEN, 400 data->rand.r.x, EAP_PAX_RAND_LEN, 401 data->rand.r.y, EAP_PAX_RAND_LEN, 402 (u8 *) data->cid, data->cid_len, mac); 403 if (os_memcmp(mac, pos, EAP_PAX_MAC_LEN) != 0) { 404 wpa_printf(MSG_INFO, "EAP-PAX: Invalid MAC_CK(A, B, CID) in " 405 "PAX_STD-2"); 406 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: Expected MAC_CK(A, B, CID)", 407 mac, EAP_PAX_MAC_LEN); 408 data->state = FAILURE; 409 return; 410 } 411 412 pos += EAP_PAX_MAC_LEN; 413 left -= EAP_PAX_MAC_LEN; 414 415 if (left < EAP_PAX_ICV_LEN) { 416 wpa_printf(MSG_INFO, "EAP-PAX: Too short ICV (%lu) in " 417 "PAX_STD-2", (unsigned long) left); 418 return; 419 } 420 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", pos, EAP_PAX_ICV_LEN); 421 eap_pax_mac(data->mac_id, data->ick, EAP_PAX_ICK_LEN, 422 wpabuf_head(respData), 423 wpabuf_len(respData) - EAP_PAX_ICV_LEN, NULL, 0, NULL, 0, 424 icvbuf); 425 if (os_memcmp(icvbuf, pos, EAP_PAX_ICV_LEN) != 0) { 426 wpa_printf(MSG_INFO, "EAP-PAX: Invalid ICV in PAX_STD-2"); 427 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: Expected ICV", 428 icvbuf, EAP_PAX_ICV_LEN); 429 return; 430 } 431 pos += EAP_PAX_ICV_LEN; 432 left -= EAP_PAX_ICV_LEN; 433 434 if (left > 0) { 435 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ignored extra payload", 436 pos, left); 437 } 438 439 data->state = PAX_STD_3; 440} 441 442 443static void eap_pax_process_ack(struct eap_sm *sm, 444 struct eap_pax_data *data, 445 struct wpabuf *respData) 446{ 447 if (data->state != PAX_STD_3) 448 return; 449 450 wpa_printf(MSG_DEBUG, "EAP-PAX: Received PAX-ACK - authentication " 451 "completed successfully"); 452 data->state = SUCCESS; 453} 454 455 456static void eap_pax_process(struct eap_sm *sm, void *priv, 457 struct wpabuf *respData) 458{ 459 struct eap_pax_data *data = priv; 460 struct eap_pax_hdr *resp; 461 const u8 *pos; 462 size_t len; 463 464 if (sm->user == NULL || sm->user->password == NULL) { 465 wpa_printf(MSG_INFO, "EAP-PAX: Plaintext password not " 466 "configured"); 467 data->state = FAILURE; 468 return; 469 } 470 471 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PAX, respData, &len); 472 if (pos == NULL || len < sizeof(*resp)) 473 return; 474 475 resp = (struct eap_pax_hdr *) pos; 476 477 switch (resp->op_code) { 478 case EAP_PAX_OP_STD_2: 479 eap_pax_process_std_2(sm, data, respData); 480 break; 481 case EAP_PAX_OP_ACK: 482 eap_pax_process_ack(sm, data, respData); 483 break; 484 } 485} 486 487 488static Boolean eap_pax_isDone(struct eap_sm *sm, void *priv) 489{ 490 struct eap_pax_data *data = priv; 491 return data->state == SUCCESS || data->state == FAILURE; 492} 493 494 495static u8 * eap_pax_getKey(struct eap_sm *sm, void *priv, size_t *len) 496{ 497 struct eap_pax_data *data = priv; 498 u8 *key; 499 500 if (data->state != SUCCESS) 501 return NULL; 502 503 key = os_malloc(EAP_MSK_LEN); 504 if (key == NULL) 505 return NULL; 506 507 *len = EAP_MSK_LEN; 508 eap_pax_kdf(data->mac_id, data->mk, EAP_PAX_MK_LEN, 509 "Master Session Key", data->rand.e, 2 * EAP_PAX_RAND_LEN, 510 EAP_MSK_LEN, key); 511 512 return key; 513} 514 515 516static u8 * eap_pax_get_emsk(struct eap_sm *sm, void *priv, size_t *len) 517{ 518 struct eap_pax_data *data = priv; 519 u8 *key; 520 521 if (data->state != SUCCESS) 522 return NULL; 523 524 key = os_malloc(EAP_EMSK_LEN); 525 if (key == NULL) 526 return NULL; 527 528 *len = EAP_EMSK_LEN; 529 eap_pax_kdf(data->mac_id, data->mk, EAP_PAX_MK_LEN, 530 "Extended Master Session Key", 531 data->rand.e, 2 * EAP_PAX_RAND_LEN, 532 EAP_EMSK_LEN, key); 533 534 return key; 535} 536 537 538static Boolean eap_pax_isSuccess(struct eap_sm *sm, void *priv) 539{ 540 struct eap_pax_data *data = priv; 541 return data->state == SUCCESS; 542} 543 544 545int eap_server_pax_register(void) 546{ 547 struct eap_method *eap; 548 int ret; 549 550 eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION, 551 EAP_VENDOR_IETF, EAP_TYPE_PAX, "PAX"); 552 if (eap == NULL) 553 return -1; 554 555 eap->init = eap_pax_init; 556 eap->reset = eap_pax_reset; 557 eap->buildReq = eap_pax_buildReq; 558 eap->check = eap_pax_check; 559 eap->process = eap_pax_process; 560 eap->isDone = eap_pax_isDone; 561 eap->getKey = eap_pax_getKey; 562 eap->isSuccess = eap_pax_isSuccess; 563 eap->get_emsk = eap_pax_get_emsk; 564 565 ret = eap_server_method_register(eap); 566 if (ret) 567 eap_server_method_free(eap); 568 return ret; 569} 570