www.project-moonshot.org Git - mech_eap.orig/blob - libeap/src/eap_peer/eap_pax.c

   1 /*
   2  * EAP peer method: EAP-PAX (RFC 4746)
   3  * Copyright (c) 2005-2008, 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_common/eap_pax_common.h"
  19 #include "eap_i.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
  30 struct eap_pax_data {
  31         enum { PAX_INIT, PAX_STD_2_SENT, PAX_DONE } state;
  32         u8 mac_id, dh_group_id, public_key_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         char *cid;
  41         size_t cid_len;
  42         u8 ak[EAP_PAX_AK_LEN];
  43         u8 mk[EAP_PAX_MK_LEN];
  44         u8 ck[EAP_PAX_CK_LEN];
  45         u8 ick[EAP_PAX_ICK_LEN];
  46 };
  47
  48
  49 static void eap_pax_deinit(struct eap_sm *sm, void *priv);
  50
  51
  52 static void * eap_pax_init(struct eap_sm *sm)
  53 {
  54         struct eap_pax_data *data;
  55         const u8 *identity, *password;
  56         size_t identity_len, password_len;
  57
  58         identity = eap_get_config_identity(sm, &identity_len);
  59         password = eap_get_config_password(sm, &password_len);
  60         if (!identity || !password) {
  61                 wpa_printf(MSG_INFO, "EAP-PAX: CID (nai) or key (password) "
  62                            "not configured");
  63                 return NULL;
  64         }
  65
  66         if (password_len != EAP_PAX_AK_LEN) {
  67                 wpa_printf(MSG_INFO, "EAP-PAX: Invalid PSK length");
  68                 return NULL;
  69         }
  70
  71         data = os_zalloc(sizeof(*data));
  72         if (data == NULL)
  73                 return NULL;
  74         data->state = PAX_INIT;
  75
  76         data->cid = os_malloc(identity_len);
  77         if (data->cid == NULL) {
  78                 eap_pax_deinit(sm, data);
  79                 return NULL;
  80         }
  81         os_memcpy(data->cid, identity, identity_len);
  82         data->cid_len = identity_len;
  83
  84         os_memcpy(data->ak, password, EAP_PAX_AK_LEN);
  85
  86         return data;
  87 }
  88
  89
  90 static void eap_pax_deinit(struct eap_sm *sm, void *priv)
  91 {
  92         struct eap_pax_data *data = priv;
  93         os_free(data->cid);
  94         os_free(data);
  95 }
  96
  97
  98 static struct wpabuf * eap_pax_alloc_resp(const struct eap_pax_hdr *req,
  99                                           u8 id, u8 op_code, size_t plen)
 100 {
 101         struct wpabuf *resp;
 102         struct eap_pax_hdr *pax;
 103
 104         resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PAX,
 105                              sizeof(*pax) + plen, EAP_CODE_RESPONSE, id);
 106         if (resp == NULL)
 107                 return NULL;
 108
 109         pax = wpabuf_put(resp, sizeof(*pax));
 110         pax->op_code = op_code;
 111         pax->flags = 0;
 112         pax->mac_id = req->mac_id;
 113         pax->dh_group_id = req->dh_group_id;
 114         pax->public_key_id = req->public_key_id;
 115
 116         return resp;
 117 }
 118
 119
 120 static struct wpabuf * eap_pax_process_std_1(struct eap_pax_data *data,
 121                                              struct eap_method_ret *ret, u8 id,
 122                                              const struct eap_pax_hdr *req,
 123                                              size_t req_plen)
 124 {
 125         struct wpabuf *resp;
 126         const u8 *pos;
 127         u8 *rpos;
 128         size_t left, plen;
 129
 130         wpa_printf(MSG_DEBUG, "EAP-PAX: PAX_STD-1 (received)");
 131
 132         if (data->state != PAX_INIT) {
 133                 wpa_printf(MSG_INFO, "EAP-PAX: PAX_STD-1 received in "
 134                            "unexpected state (%d) - ignored", data->state);
 135                 ret->ignore = TRUE;
 136                 return NULL;
 137         }
 138
 139         if (req->flags & EAP_PAX_FLAGS_CE) {
 140                 wpa_printf(MSG_INFO, "EAP-PAX: PAX_STD-1 with CE flag set - "
 141                            "ignored");
 142                 ret->ignore = TRUE;
 143                 return NULL;
 144         }
 145
 146         left = req_plen - sizeof(*req);
 147
 148         if (left < 2 + EAP_PAX_RAND_LEN) {
 149                 wpa_printf(MSG_INFO, "EAP-PAX: PAX_STD-1 with too short "
 150                            "payload");
 151                 ret->ignore = TRUE;
 152                 return NULL;
 153         }
 154
 155         pos = (const u8 *) (req + 1);
 156         if (WPA_GET_BE16(pos) != EAP_PAX_RAND_LEN) {
 157                 wpa_printf(MSG_INFO, "EAP-PAX: PAX_STD-1 with incorrect A "
 158                            "length %d (expected %d)",
 159                            WPA_GET_BE16(pos), EAP_PAX_RAND_LEN);
 160                 ret->ignore = TRUE;
 161                 return NULL;
 162         }
 163
 164         pos += 2;
 165         left -= 2;
 166         os_memcpy(data->rand.r.x, pos, EAP_PAX_RAND_LEN);
 167         wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: X (server rand)",
 168                     data->rand.r.x, EAP_PAX_RAND_LEN);
 169         pos += EAP_PAX_RAND_LEN;
 170         left -= EAP_PAX_RAND_LEN;
 171
 172         if (left > 0) {
 173                 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ignored extra payload",
 174                             pos, left);
 175         }
 176
 177         if (os_get_random(data->rand.r.y, EAP_PAX_RAND_LEN)) {
 178                 wpa_printf(MSG_ERROR, "EAP-PAX: Failed to get random data");
 179                 ret->ignore = TRUE;
 180                 return NULL;
 181         }
 182         wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: Y (client rand)",
 183                     data->rand.r.y, EAP_PAX_RAND_LEN);
 184
 185         if (eap_pax_initial_key_derivation(req->mac_id, data->ak, data->rand.e,
 186                                            data->mk, data->ck, data->ick) < 0)
 187         {
 188                 ret->ignore = TRUE;
 189                 return NULL;
 190         }
 191
 192         wpa_printf(MSG_DEBUG, "EAP-PAX: PAX_STD-2 (sending)");
 193
 194         plen = 2 + EAP_PAX_RAND_LEN + 2 + data->cid_len + 2 + EAP_PAX_MAC_LEN +
 195                 EAP_PAX_ICV_LEN;
 196         resp = eap_pax_alloc_resp(req, id, EAP_PAX_OP_STD_2, plen);
 197         if (resp == NULL)
 198                 return NULL;
 199
 200         wpabuf_put_be16(resp, EAP_PAX_RAND_LEN);
 201         wpabuf_put_data(resp, data->rand.r.y, EAP_PAX_RAND_LEN);
 202         wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: B = Y (client rand)",
 203                     data->rand.r.y, EAP_PAX_RAND_LEN);
 204
 205         wpabuf_put_be16(resp, data->cid_len);
 206         wpabuf_put_data(resp, data->cid, data->cid_len);
 207         wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-PAX: CID",
 208                           (u8 *) data->cid, data->cid_len);
 209
 210         wpabuf_put_be16(resp, EAP_PAX_MAC_LEN);
 211         rpos = wpabuf_put(resp, EAP_PAX_MAC_LEN);
 212         eap_pax_mac(req->mac_id, data->ck, EAP_PAX_CK_LEN,
 213                     data->rand.r.x, EAP_PAX_RAND_LEN,
 214                     data->rand.r.y, EAP_PAX_RAND_LEN,
 215                     (u8 *) data->cid, data->cid_len, rpos);
 216         wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: MAC_CK(A, B, CID)",
 217                     rpos, EAP_PAX_MAC_LEN);
 218
 219         /* Optional ADE could be added here, if needed */
 220
 221         rpos = wpabuf_put(resp, EAP_PAX_ICV_LEN);
 222         eap_pax_mac(req->mac_id, data->ick, EAP_PAX_ICK_LEN,
 223                     wpabuf_head(resp), wpabuf_len(resp) - EAP_PAX_ICV_LEN,
 224                     NULL, 0, NULL, 0, rpos);
 225         wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", rpos, EAP_PAX_ICV_LEN);
 226
 227         data->state = PAX_STD_2_SENT;
 228         data->mac_id = req->mac_id;
 229         data->dh_group_id = req->dh_group_id;
 230         data->public_key_id = req->public_key_id;
 231
 232         return resp;
 233 }
 234
 235
 236 static struct wpabuf * eap_pax_process_std_3(struct eap_pax_data *data,
 237                                              struct eap_method_ret *ret, u8 id,
 238                                              const struct eap_pax_hdr *req,
 239                                              size_t req_plen)
 240 {
 241         struct wpabuf *resp;
 242         u8 *rpos, mac[EAP_PAX_MAC_LEN];
 243         const u8 *pos;
 244         size_t left;
 245
 246         wpa_printf(MSG_DEBUG, "EAP-PAX: PAX_STD-3 (received)");
 247
 248         if (data->state != PAX_STD_2_SENT) {
 249                 wpa_printf(MSG_INFO, "EAP-PAX: PAX_STD-3 received in "
 250                            "unexpected state (%d) - ignored", data->state);
 251                 ret->ignore = TRUE;
 252                 return NULL;
 253         }
 254
 255         if (req->flags & EAP_PAX_FLAGS_CE) {
 256                 wpa_printf(MSG_INFO, "EAP-PAX: PAX_STD-3 with CE flag set - "
 257                            "ignored");
 258                 ret->ignore = TRUE;
 259                 return NULL;
 260         }
 261
 262         left = req_plen - sizeof(*req);
 263
 264         if (left < 2 + EAP_PAX_MAC_LEN) {
 265                 wpa_printf(MSG_INFO, "EAP-PAX: PAX_STD-3 with too short "
 266                            "payload");
 267                 ret->ignore = TRUE;
 268                 return NULL;
 269         }
 270
 271         pos = (const u8 *) (req + 1);
 272         if (WPA_GET_BE16(pos) != EAP_PAX_MAC_LEN) {
 273                 wpa_printf(MSG_INFO, "EAP-PAX: PAX_STD-3 with incorrect "
 274                            "MAC_CK length %d (expected %d)",
 275                            WPA_GET_BE16(pos), EAP_PAX_MAC_LEN);
 276                 ret->ignore = TRUE;
 277                 return NULL;
 278         }
 279         pos += 2;
 280         left -= 2;
 281         wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: MAC_CK(B, CID)",
 282                     pos, EAP_PAX_MAC_LEN);
 283         eap_pax_mac(data->mac_id, data->ck, EAP_PAX_CK_LEN,
 284                     data->rand.r.y, EAP_PAX_RAND_LEN,
 285                     (u8 *) data->cid, data->cid_len, NULL, 0, mac);
 286         if (os_memcmp(pos, mac, EAP_PAX_MAC_LEN) != 0) {
 287                 wpa_printf(MSG_INFO, "EAP-PAX: Invalid MAC_CK(B, CID) "
 288                            "received");
 289                 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: expected MAC_CK(B, CID)",
 290                             mac, EAP_PAX_MAC_LEN);
 291                 ret->methodState = METHOD_DONE;
 292                 ret->decision = DECISION_FAIL;
 293                 return NULL;
 294         }
 295
 296         pos += EAP_PAX_MAC_LEN;
 297         left -= EAP_PAX_MAC_LEN;
 298
 299         if (left > 0) {
 300                 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ignored extra payload",
 301                             pos, left);
 302         }
 303
 304         wpa_printf(MSG_DEBUG, "EAP-PAX: PAX-ACK (sending)");
 305
 306         resp = eap_pax_alloc_resp(req, id, EAP_PAX_OP_ACK, EAP_PAX_ICV_LEN);
 307         if (resp == NULL)
 308                 return NULL;
 309
 310         /* Optional ADE could be added here, if needed */
 311
 312         rpos = wpabuf_put(resp, EAP_PAX_ICV_LEN);
 313         eap_pax_mac(data->mac_id, data->ick, EAP_PAX_ICK_LEN,
 314                     wpabuf_head(resp), wpabuf_len(resp) - EAP_PAX_ICV_LEN,
 315                     NULL, 0, NULL, 0, rpos);
 316         wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", rpos, EAP_PAX_ICV_LEN);
 317
 318         data->state = PAX_DONE;
 319         ret->methodState = METHOD_DONE;
 320         ret->decision = DECISION_UNCOND_SUCC;
 321         ret->allowNotifications = FALSE;
 322
 323         return resp;
 324 }
 325
 326
 327 static struct wpabuf * eap_pax_process(struct eap_sm *sm, void *priv,
 328                                        struct eap_method_ret *ret,
 329                                        const struct wpabuf *reqData)
 330 {
 331         struct eap_pax_data *data = priv;
 332         const struct eap_pax_hdr *req;
 333         struct wpabuf *resp;
 334         u8 icvbuf[EAP_PAX_ICV_LEN], id;
 335         const u8 *icv, *pos;
 336         size_t len;
 337         u16 flen, mlen;
 338
 339         pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PAX, reqData, &len);
 340         if (pos == NULL || len < EAP_PAX_ICV_LEN) {
 341                 ret->ignore = TRUE;
 342                 return NULL;
 343         }
 344         id = eap_get_id(reqData);
 345         req = (const struct eap_pax_hdr *) pos;
 346         flen = len - EAP_PAX_ICV_LEN;
 347         mlen = wpabuf_len(reqData) - EAP_PAX_ICV_LEN;
 348
 349         wpa_printf(MSG_DEBUG, "EAP-PAX: received frame: op_code 0x%x "
 350                    "flags 0x%x mac_id 0x%x dh_group_id 0x%x "
 351                    "public_key_id 0x%x",
 352                    req->op_code, req->flags, req->mac_id, req->dh_group_id,
 353                    req->public_key_id);
 354         wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: received payload",
 355                     pos, len - EAP_PAX_ICV_LEN);
 356
 357         if (data->state != PAX_INIT && data->mac_id != req->mac_id) {
 358                 wpa_printf(MSG_INFO, "EAP-PAX: MAC ID changed during "
 359                            "authentication (was 0x%d, is 0x%d)",
 360                            data->mac_id, req->mac_id);
 361                 ret->ignore = TRUE;
 362                 return NULL;
 363         }
 364
 365         if (data->state != PAX_INIT && data->dh_group_id != req->dh_group_id) {
 366                 wpa_printf(MSG_INFO, "EAP-PAX: DH Group ID changed during "
 367                            "authentication (was 0x%d, is 0x%d)",
 368                            data->dh_group_id, req->dh_group_id);
 369                 ret->ignore = TRUE;
 370                 return NULL;
 371         }
 372
 373         if (data->state != PAX_INIT &&
 374             data->public_key_id != req->public_key_id) {
 375                 wpa_printf(MSG_INFO, "EAP-PAX: Public Key ID changed during "
 376                            "authentication (was 0x%d, is 0x%d)",
 377                            data->public_key_id, req->public_key_id);
 378                 ret->ignore = TRUE;
 379                 return NULL;
 380         }
 381
 382         /* TODO: add support EAP_PAX_HMAC_SHA256_128 */
 383         if (req->mac_id != EAP_PAX_MAC_HMAC_SHA1_128) {
 384                 wpa_printf(MSG_INFO, "EAP-PAX: Unsupported MAC ID 0x%x",
 385                            req->mac_id);
 386                 ret->ignore = TRUE;
 387                 return NULL;
 388         }
 389
 390         if (req->dh_group_id != EAP_PAX_DH_GROUP_NONE) {
 391                 wpa_printf(MSG_INFO, "EAP-PAX: Unsupported DH Group ID 0x%x",
 392                            req->dh_group_id);
 393                 ret->ignore = TRUE;
 394                 return NULL;
 395         }
 396
 397         if (req->public_key_id != EAP_PAX_PUBLIC_KEY_NONE) {
 398                 wpa_printf(MSG_INFO, "EAP-PAX: Unsupported Public Key ID 0x%x",
 399                            req->public_key_id);
 400                 ret->ignore = TRUE;
 401                 return NULL;
 402         }
 403
 404         if (req->flags & EAP_PAX_FLAGS_MF) {
 405                 /* TODO: add support for reassembling fragments */
 406                 wpa_printf(MSG_INFO, "EAP-PAX: fragmentation not supported - "
 407                            "ignored packet");
 408                 ret->ignore = TRUE;
 409                 return NULL;
 410         }
 411
 412         icv = pos + len - EAP_PAX_ICV_LEN;
 413         wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", icv, EAP_PAX_ICV_LEN);
 414         if (req->op_code == EAP_PAX_OP_STD_1) {
 415                 eap_pax_mac(req->mac_id, (u8 *) "", 0,
 416                             wpabuf_head(reqData), mlen, NULL, 0, NULL, 0,
 417                             icvbuf);
 418         } else {
 419                 eap_pax_mac(req->mac_id, data->ick, EAP_PAX_ICK_LEN,
 420                             wpabuf_head(reqData), mlen, NULL, 0, NULL, 0,
 421                             icvbuf);
 422         }
 423         if (os_memcmp(icv, icvbuf, EAP_PAX_ICV_LEN) != 0) {
 424                 wpa_printf(MSG_DEBUG, "EAP-PAX: invalid ICV - ignoring the "
 425                            "message");
 426                 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: expected ICV",
 427                             icvbuf, EAP_PAX_ICV_LEN);
 428                 ret->ignore = TRUE;
 429                 return NULL;
 430         }
 431
 432         ret->ignore = FALSE;
 433         ret->methodState = METHOD_MAY_CONT;
 434         ret->decision = DECISION_FAIL;
 435         ret->allowNotifications = TRUE;
 436
 437         switch (req->op_code) {
 438         case EAP_PAX_OP_STD_1:
 439                 resp = eap_pax_process_std_1(data, ret, id, req, flen);
 440                 break;
 441         case EAP_PAX_OP_STD_3:
 442                 resp = eap_pax_process_std_3(data, ret, id, req, flen);
 443                 break;
 444         default:
 445                 wpa_printf(MSG_DEBUG, "EAP-PAX: ignoring message with unknown "
 446                            "op_code %d", req->op_code);
 447                 ret->ignore = TRUE;
 448                 return NULL;
 449         }
 450
 451         if (ret->methodState == METHOD_DONE) {
 452                 ret->allowNotifications = FALSE;
 453         }
 454
 455         return resp;
 456 }
 457
 458
 459 static Boolean eap_pax_isKeyAvailable(struct eap_sm *sm, void *priv)
 460 {
 461         struct eap_pax_data *data = priv;
 462         return data->state == PAX_DONE;
 463 }
 464
 465
 466 static u8 * eap_pax_getKey(struct eap_sm *sm, void *priv, size_t *len)
 467 {
 468         struct eap_pax_data *data = priv;
 469         u8 *key;
 470
 471         if (data->state != PAX_DONE)
 472                 return NULL;
 473
 474         key = os_malloc(EAP_MSK_LEN);
 475         if (key == NULL)
 476                 return NULL;
 477
 478         *len = EAP_MSK_LEN;
 479         eap_pax_kdf(data->mac_id, data->mk, EAP_PAX_MK_LEN,
 480                     "Master Session Key", data->rand.e, 2 * EAP_PAX_RAND_LEN,
 481                     EAP_MSK_LEN, key);
 482
 483         return key;
 484 }
 485
 486
 487 static u8 * eap_pax_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
 488 {
 489         struct eap_pax_data *data = priv;
 490         u8 *key;
 491
 492         if (data->state != PAX_DONE)
 493                 return NULL;
 494
 495         key = os_malloc(EAP_EMSK_LEN);
 496         if (key == NULL)
 497                 return NULL;
 498
 499         *len = EAP_EMSK_LEN;
 500         eap_pax_kdf(data->mac_id, data->mk, EAP_PAX_MK_LEN,
 501                     "Extended Master Session Key",
 502                     data->rand.e, 2 * EAP_PAX_RAND_LEN,
 503                     EAP_EMSK_LEN, key);
 504
 505         return key;
 506 }
 507
 508
 509 int eap_peer_pax_register(void)
 510 {
 511         struct eap_method *eap;
 512         int ret;
 513
 514         eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
 515                                     EAP_VENDOR_IETF, EAP_TYPE_PAX, "PAX");
 516         if (eap == NULL)
 517                 return -1;
 518
 519         eap->init = eap_pax_init;
 520         eap->deinit = eap_pax_deinit;
 521         eap->process = eap_pax_process;
 522         eap->isKeyAvailable = eap_pax_isKeyAvailable;
 523         eap->getKey = eap_pax_getKey;
 524         eap->get_emsk = eap_pax_get_emsk;
 525
 526         ret = eap_peer_method_register(eap);
 527         if (ret)
 528                 eap_peer_method_free(eap);
 529         return ret;
 530 }