contrib/hostapd-0.4.9/eap_pax.c

   1 /*
   2  * hostapd / EAP-PAX (draft-clancy-eap-pax-04.txt) server
   3  * Copyright (c) 2005, Jouni Malinen <jkmaline@cc.hut.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 <stdlib.h>
  16 #include <stdio.h>
  17 #include <string.h>
  18 #include <netinet/in.h>
  19
  20 #include "hostapd.h"
  21 #include "common.h"
  22 #include "eap_i.h"
  23 #include "eap_pax_common.h"
  24
  25 /*
  26  * Note: only PAX_STD subprotocol is currently supported
  27  */
  28
  29 struct eap_pax_data {
  30         enum { PAX_STD_1, PAX_STD_3, SUCCESS, FAILURE } state;
  31         u8 mac_id;
  32         union {
  33                 u8 e[2 * EAP_PAX_RAND_LEN];
  34                 struct {
  35                         u8 x[EAP_PAX_RAND_LEN]; /* server rand */
  36                         u8 y[EAP_PAX_RAND_LEN]; /* client rand */
  37                 } r;
  38         } rand;
  39         u8 ak[EAP_PAX_AK_LEN];
  40         u8 mk[EAP_PAX_MK_LEN];
  41         u8 ck[EAP_PAX_CK_LEN];
  42         u8 ick[EAP_PAX_ICK_LEN];
  43         int keys_set;
  44         char *cid;
  45         size_t cid_len;
  46 };
  47
  48
  49 static void * eap_pax_init(struct eap_sm *sm)
  50 {
  51         struct eap_pax_data *data;
  52
  53         data = malloc(sizeof(*data));
  54         if (data == NULL)
  55                 return data;
  56         memset(data, 0, sizeof(*data));
  57         data->state = PAX_STD_1;
  58         /*
  59          * TODO: make this configurable once EAP_PAX_MAC_AES_CBC_MAC_128 is
  60          * supported
  61          */
  62         data->mac_id = EAP_PAX_MAC_HMAC_SHA1_128;
  63
  64         return data;
  65 }
  66
  67
  68 static void eap_pax_reset(struct eap_sm *sm, void *priv)
  69 {
  70         struct eap_pax_data *data = priv;
  71         free(data->cid);
  72         free(data);
  73 }
  74
  75
  76 static u8 * eap_pax_build_std_1(struct eap_sm *sm,
  77                                 struct eap_pax_data *data,
  78                                 int id, size_t *reqDataLen)
  79 {
  80         struct eap_pax_hdr *req;
  81         u8 *pos;
  82
  83         wpa_printf(MSG_DEBUG, "EAP-PAX: PAX_STD-1 (sending)");
  84
  85         if (hostapd_get_rand(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         *reqDataLen = sizeof(*req) + 2 + EAP_PAX_RAND_LEN + EAP_PAX_ICV_LEN;
  92         req = malloc(*reqDataLen);
  93         if (req == NULL) {
  94                 wpa_printf(MSG_ERROR, "EAP-PAX: Failed to allocate memory "
  95                            "request");
  96                 data->state = FAILURE;
  97                 return NULL;
  98         }
  99
 100         req->code = EAP_CODE_REQUEST;
 101         req->identifier = id;
 102         req->length = htons(*reqDataLen);
 103         req->type = EAP_TYPE_PAX;
 104         req->op_code = EAP_PAX_OP_STD_1;
 105         req->flags = 0;
 106         req->mac_id = data->mac_id;
 107         req->dh_group_id = EAP_PAX_DH_GROUP_NONE;
 108         req->public_key_id = EAP_PAX_PUBLIC_KEY_NONE;
 109         pos = (u8 *) (req + 1);
 110         *pos++ = 0;
 111         *pos++ = EAP_PAX_RAND_LEN;
 112         memcpy(pos, data->rand.r.x, EAP_PAX_RAND_LEN);
 113         wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: A = X (server rand)",
 114                     pos, EAP_PAX_RAND_LEN);
 115         pos += EAP_PAX_RAND_LEN;
 116
 117         eap_pax_mac(data->mac_id, (u8 *) "", 0,
 118                     (u8 *) req, *reqDataLen - EAP_PAX_ICV_LEN,
 119                     NULL, 0, NULL, 0, pos);
 120         wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", pos, EAP_PAX_ICV_LEN);
 121         pos += EAP_PAX_ICV_LEN;
 122
 123         return (u8 *) req;
 124 }
 125
 126
 127 static u8 * eap_pax_build_std_3(struct eap_sm *sm,
 128                                 struct eap_pax_data *data,
 129                                 int id, size_t *reqDataLen)
 130 {
 131         struct eap_pax_hdr *req;
 132         u8 *pos;
 133
 134         wpa_printf(MSG_DEBUG, "EAP-PAX: PAX_STD-3 (sending)");
 135
 136         *reqDataLen = sizeof(*req) + 2 + EAP_PAX_MAC_LEN + EAP_PAX_ICV_LEN;
 137         req = malloc(*reqDataLen);
 138         if (req == NULL) {
 139                 wpa_printf(MSG_ERROR, "EAP-PAX: Failed to allocate memory "
 140                            "request");
 141                 data->state = FAILURE;
 142                 return NULL;
 143         }
 144
 145         req->code = EAP_CODE_REQUEST;
 146         req->identifier = id;
 147         req->length = htons(*reqDataLen);
 148         req->type = EAP_TYPE_PAX;
 149         req->op_code = EAP_PAX_OP_STD_3;
 150         req->flags = 0;
 151         req->mac_id = data->mac_id;
 152         req->dh_group_id = EAP_PAX_DH_GROUP_NONE;
 153         req->public_key_id = EAP_PAX_PUBLIC_KEY_NONE;
 154         pos = (u8 *) (req + 1);
 155         *pos++ = 0;
 156         *pos++ = EAP_PAX_MAC_LEN;
 157         eap_pax_mac(data->mac_id, data->ck, EAP_PAX_CK_LEN,
 158                     data->rand.r.y, EAP_PAX_RAND_LEN,
 159                     (u8 *) data->cid, data->cid_len, NULL, 0, pos);
 160         wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: MAC_CK(B, CID)",
 161                     pos, EAP_PAX_MAC_LEN);
 162         pos += EAP_PAX_MAC_LEN;
 163
 164         eap_pax_mac(data->mac_id, data->ick, EAP_PAX_ICK_LEN,
 165                     (u8 *) req, *reqDataLen - EAP_PAX_ICV_LEN,
 166                     NULL, 0, NULL, 0, pos);
 167         wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", pos, EAP_PAX_ICV_LEN);
 168         pos += EAP_PAX_ICV_LEN;
 169
 170         return (u8 *) req;
 171 }
 172
 173
 174 static u8 * eap_pax_buildReq(struct eap_sm *sm, void *priv, int id,
 175                                   size_t *reqDataLen)
 176 {
 177         struct eap_pax_data *data = priv;
 178
 179         switch (data->state) {
 180         case PAX_STD_1:
 181                 return eap_pax_build_std_1(sm, data, id, reqDataLen);
 182         case PAX_STD_3:
 183                 return eap_pax_build_std_3(sm, data, id, reqDataLen);
 184         default:
 185                 wpa_printf(MSG_DEBUG, "EAP-PAX: Unknown state %d in buildReq",
 186                            data->state);
 187                 break;
 188         }
 189         return NULL;
 190 }
 191
 192
 193 static Boolean eap_pax_check(struct eap_sm *sm, void *priv,
 194                              u8 *respData, size_t respDataLen)
 195 {
 196         struct eap_pax_data *data = priv;
 197         struct eap_pax_hdr *resp;
 198         size_t len;
 199         u8 icvbuf[EAP_PAX_ICV_LEN], *icv;
 200
 201         resp = (struct eap_pax_hdr *) respData;
 202         if (respDataLen < sizeof(*resp) || resp->type != EAP_TYPE_PAX ||
 203             (len = ntohs(resp->length)) > respDataLen ||
 204             len < sizeof(*resp) + EAP_PAX_ICV_LEN) {
 205                 wpa_printf(MSG_INFO, "EAP-PAX: Invalid frame");
 206                 return TRUE;
 207         }
 208
 209         wpa_printf(MSG_DEBUG, "EAP-PAX: received frame: op_code 0x%x "
 210                    "flags 0x%x mac_id 0x%x dh_group_id 0x%x "
 211                    "public_key_id 0x%x",
 212                    resp->op_code, resp->flags, resp->mac_id, resp->dh_group_id,
 213                    resp->public_key_id);
 214         wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: received payload",
 215                     (u8 *) (resp + 1), len - sizeof(*resp) - EAP_PAX_ICV_LEN);
 216
 217         if (data->state == PAX_STD_1 &&
 218             resp->op_code != EAP_PAX_OP_STD_2) {
 219                 wpa_printf(MSG_DEBUG, "EAP-PAX: Expected PAX_STD-2 - "
 220                            "ignore op %d", resp->op_code);
 221                 return TRUE;
 222         }
 223
 224         if (data->state == PAX_STD_3 &&
 225             resp->op_code != EAP_PAX_OP_ACK) {
 226                 wpa_printf(MSG_DEBUG, "EAP-PAX: Expected PAX-ACK - "
 227                            "ignore op %d", resp->op_code);
 228                 return TRUE;
 229         }
 230
 231         if (resp->op_code != EAP_PAX_OP_STD_2 &&
 232             resp->op_code != EAP_PAX_OP_ACK) {
 233                 wpa_printf(MSG_DEBUG, "EAP-PAX: Unknown op_code 0x%x",
 234                            resp->op_code);
 235         }
 236
 237         if (data->mac_id != resp->mac_id) {
 238                 wpa_printf(MSG_DEBUG, "EAP-PAX: Expected MAC ID 0x%x, "
 239                            "received 0x%x", data->mac_id, resp->mac_id);
 240                 return TRUE;
 241         }
 242
 243         if (resp->dh_group_id != EAP_PAX_DH_GROUP_NONE) {
 244                 wpa_printf(MSG_INFO, "EAP-PAX: Expected DH Group ID 0x%x, "
 245                            "received 0x%x", EAP_PAX_DH_GROUP_NONE,
 246                            resp->dh_group_id);
 247                 return TRUE;
 248         }
 249
 250         if (resp->public_key_id != EAP_PAX_PUBLIC_KEY_NONE) {
 251                 wpa_printf(MSG_INFO, "EAP-PAX: Expected Public Key ID 0x%x, "
 252                            "received 0x%x", EAP_PAX_PUBLIC_KEY_NONE,
 253                            resp->public_key_id);
 254                 return TRUE;
 255         }
 256
 257         if (resp->flags & EAP_PAX_FLAGS_MF) {
 258                 /* TODO: add support for reassembling fragments */
 259                 wpa_printf(MSG_INFO, "EAP-PAX: fragmentation not supported");
 260                 return TRUE;
 261         }
 262
 263         if (resp->flags & EAP_PAX_FLAGS_CE) {
 264                 wpa_printf(MSG_INFO, "EAP-PAX: Unexpected CE flag");
 265                 return TRUE;
 266         }
 267
 268         if (data->keys_set) {
 269                 if (len - sizeof(*resp) < EAP_PAX_ICV_LEN) {
 270                         wpa_printf(MSG_INFO, "EAP-PAX: No ICV in the packet");
 271                         return TRUE;
 272                 }
 273                 icv = respData + len - EAP_PAX_ICV_LEN;
 274                 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", icv, EAP_PAX_ICV_LEN);
 275                 eap_pax_mac(data->mac_id, data->ick, EAP_PAX_ICK_LEN,
 276                             respData, len - EAP_PAX_ICV_LEN, NULL, 0, NULL, 0,
 277                             icvbuf);
 278                 if (memcmp(icvbuf, icv, EAP_PAX_ICV_LEN) != 0) {
 279                         wpa_printf(MSG_INFO, "EAP-PAX: Invalid ICV");
 280                         wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: Expected ICV",
 281                                     icvbuf, EAP_PAX_ICV_LEN);
 282                         return TRUE;
 283                 }
 284         }
 285
 286         return FALSE;
 287 }
 288
 289
 290 static void eap_pax_process_std_2(struct eap_sm *sm,
 291                                   struct eap_pax_data *data,
 292                                   u8 *respData, size_t respDataLen)
 293 {
 294         struct eap_pax_hdr *resp;
 295         u8 *pos, mac[EAP_PAX_MAC_LEN], icvbuf[EAP_PAX_ICV_LEN];
 296         size_t len, left;
 297         int i;
 298
 299         if (data->state != PAX_STD_1)
 300                 return;
 301
 302         wpa_printf(MSG_DEBUG, "EAP-PAX: Received PAX_STD-2");
 303
 304         resp = (struct eap_pax_hdr *) respData;
 305         len = ntohs(resp->length);
 306         pos = (u8 *) (resp + 1);
 307         left = len - sizeof(*resp);
 308
 309         if (left < 2 + EAP_PAX_RAND_LEN ||
 310             ((pos[0] << 8) | pos[1]) != EAP_PAX_RAND_LEN) {
 311                 wpa_printf(MSG_INFO, "EAP-PAX: Too short PAX_STD-2 (B)");
 312                 return;
 313         }
 314         pos += 2;
 315         left -= 2;
 316         memcpy(data->rand.r.y, pos, EAP_PAX_RAND_LEN);
 317         wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: Y (client rand)",
 318                     data->rand.r.y, EAP_PAX_RAND_LEN);
 319         pos += EAP_PAX_RAND_LEN;
 320         left -= EAP_PAX_RAND_LEN;
 321
 322         if (left < 2 || 2 + ((pos[0] << 8) | pos[1]) > left) {
 323                 wpa_printf(MSG_INFO, "EAP-PAX: Too short PAX_STD-2 (CID)");
 324                 return;
 325         }
 326         data->cid_len = (pos[0] << 8) | pos[1];
 327         free(data->cid);
 328         data->cid = malloc(data->cid_len);
 329         if (data->cid == NULL) {
 330                 wpa_printf(MSG_INFO, "EAP-PAX: Failed to allocate memory for "
 331                            "CID");
 332                 return;
 333         }
 334         memcpy (data->cid, pos + 2, data->cid_len);
 335         pos += 2 + data->cid_len;
 336         left -= 2 + data->cid_len;
 337         wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-PAX: CID",
 338                           (u8 *) data->cid, data->cid_len);
 339
 340         if (left < 2 + EAP_PAX_MAC_LEN ||
 341             ((pos[0] << 8) | pos[1]) != EAP_PAX_MAC_LEN) {
 342                 wpa_printf(MSG_INFO, "EAP-PAX: Too short PAX_STD-2 (MAC_CK)");
 343                 return;
 344         }
 345         pos += 2;
 346         left -= 2;
 347         wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: MAC_CK(A, B, CID)",
 348                     pos, EAP_PAX_MAC_LEN);
 349
 350         if (eap_user_get(sm, (u8 *) data->cid, data->cid_len, 0) < 0) {
 351                 wpa_hexdump_ascii(MSG_DEBUG, "EAP-PAX: unknown CID",
 352                                   (u8 *) data->cid, data->cid_len);
 353                 data->state = FAILURE;
 354                 return;
 355         }
 356
 357         for (i = 0;
 358              i < EAP_MAX_METHODS && sm->user->methods[i] != EAP_TYPE_NONE;
 359              i++) {
 360                 if (sm->user->methods[i] == EAP_TYPE_PAX)
 361                         break;
 362         }
 363
 364         if (sm->user->methods[i] != EAP_TYPE_PAX) {
 365                 wpa_hexdump_ascii(MSG_DEBUG,
 366                                   "EAP-PAX: EAP-PAX not enabled for CID",
 367                                   (u8 *) data->cid, data->cid_len);
 368                 data->state = FAILURE;
 369                 return;
 370         }
 371
 372         if (sm->user->password == NULL ||
 373             sm->user->password_len != EAP_PAX_AK_LEN) {
 374                 wpa_hexdump_ascii(MSG_DEBUG, "EAP-PAX: invalid password in "
 375                                   "user database for CID",
 376                                   (u8 *) data->cid, data->cid_len);
 377                 data->state = FAILURE;
 378                 return;
 379         }
 380         memcpy(data->ak, sm->user->password, EAP_PAX_AK_LEN);
 381
 382         if (eap_pax_initial_key_derivation(data->mac_id, data->ak,
 383                                            data->rand.e, data->mk, data->ck,
 384                                            data->ick) < 0) {
 385                 wpa_printf(MSG_INFO, "EAP-PAX: Failed to complete initial "
 386                            "key derivation");
 387                 data->state = FAILURE;
 388                 return;
 389         }
 390         data->keys_set = 1;
 391
 392         eap_pax_mac(data->mac_id, data->ck, EAP_PAX_CK_LEN,
 393                     data->rand.r.x, EAP_PAX_RAND_LEN,
 394                     data->rand.r.y, EAP_PAX_RAND_LEN,
 395                     (u8 *) data->cid, data->cid_len, mac);
 396         if (memcmp(mac, pos, EAP_PAX_MAC_LEN) != 0) {
 397                 wpa_printf(MSG_INFO, "EAP-PAX: Invalid MAC_CK(A, B, CID) in "
 398                            "PAX_STD-2");
 399                 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: Expected MAC_CK(A, B, CID)",
 400                             mac, EAP_PAX_MAC_LEN);
 401                 data->state = FAILURE;
 402                 return;
 403         }
 404
 405         pos += EAP_PAX_MAC_LEN;
 406         left -= EAP_PAX_MAC_LEN;
 407
 408         if (left < EAP_PAX_ICV_LEN) {
 409                 wpa_printf(MSG_INFO, "EAP-PAX: Too short ICV (%lu) in "
 410                            "PAX_STD-2", (unsigned long) left);
 411                 return;
 412         }
 413         wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", pos, EAP_PAX_ICV_LEN);
 414         eap_pax_mac(data->mac_id, data->ick, EAP_PAX_ICK_LEN,
 415                     respData, len - EAP_PAX_ICV_LEN, NULL, 0, NULL, 0, icvbuf);
 416         if (memcmp(icvbuf, pos, EAP_PAX_ICV_LEN) != 0) {
 417                 wpa_printf(MSG_INFO, "EAP-PAX: Invalid ICV in PAX_STD-2");
 418                 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: Expected ICV",
 419                             icvbuf, EAP_PAX_ICV_LEN);
 420                 return;
 421         }
 422         pos += EAP_PAX_ICV_LEN;
 423         left -= EAP_PAX_ICV_LEN;
 424
 425         if (left > 0) {
 426                 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ignored extra payload",
 427                             pos, left);
 428         }
 429
 430         data->state = PAX_STD_3;
 431 }
 432
 433
 434 static void eap_pax_process_ack(struct eap_sm *sm,
 435                                 struct eap_pax_data *data,
 436                                 u8 *respData, size_t respDataLen)
 437 {
 438         if (data->state != PAX_STD_3)
 439                 return;
 440
 441         wpa_printf(MSG_DEBUG, "EAP-PAX: Received PAX-ACK - authentication "
 442                    "completed successfully");
 443         data->state = SUCCESS;
 444 }
 445
 446
 447 static void eap_pax_process(struct eap_sm *sm, void *priv,
 448                                  u8 *respData, size_t respDataLen)
 449 {
 450         struct eap_pax_data *data = priv;
 451         struct eap_pax_hdr *resp;
 452
 453         if (sm->user == NULL || sm->user->password == NULL) {
 454                 wpa_printf(MSG_INFO, "EAP-PAX: Password not configured");
 455                 data->state = FAILURE;
 456                 return;
 457         }
 458
 459         resp = (struct eap_pax_hdr *) respData;
 460
 461         switch (resp->op_code) {
 462         case EAP_PAX_OP_STD_2:
 463                 eap_pax_process_std_2(sm, data, respData, respDataLen);
 464                 break;
 465         case EAP_PAX_OP_ACK:
 466                 eap_pax_process_ack(sm, data, respData, respDataLen);
 467                 break;
 468         }
 469 }
 470
 471
 472 static Boolean eap_pax_isDone(struct eap_sm *sm, void *priv)
 473 {
 474         struct eap_pax_data *data = priv;
 475         return data->state == SUCCESS || data->state == FAILURE;
 476 }
 477
 478
 479 static u8 * eap_pax_getKey(struct eap_sm *sm, void *priv, size_t *len)
 480 {
 481         struct eap_pax_data *data = priv;
 482         u8 *key;
 483
 484         if (data->state != SUCCESS)
 485                 return NULL;
 486
 487         key = malloc(EAP_PAX_MSK_LEN);
 488         if (key == NULL)
 489                 return NULL;
 490
 491         *len = EAP_PAX_MSK_LEN;
 492         eap_pax_kdf(data->mac_id, data->mk, EAP_PAX_MK_LEN,
 493                     "Master Session Key", data->rand.e, 2 * EAP_PAX_RAND_LEN,
 494                     EAP_PAX_MSK_LEN, key);
 495
 496         return key;
 497 }
 498
 499
 500 static Boolean eap_pax_isSuccess(struct eap_sm *sm, void *priv)
 501 {
 502         struct eap_pax_data *data = priv;
 503         return data->state == SUCCESS;
 504 }
 505
 506
 507 const struct eap_method eap_method_pax =
 508 {
 509         .method = EAP_TYPE_PAX,
 510         .name = "PAX",
 511         .init = eap_pax_init,
 512         .reset = eap_pax_reset,
 513         .buildReq = eap_pax_buildReq,
 514         .check = eap_pax_check,
 515         .process = eap_pax_process,
 516         .isDone = eap_pax_isDone,
 517         .getKey = eap_pax_getKey,
 518         .isSuccess = eap_pax_isSuccess,
 519 };