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

   1 /*
   2  * EAP peer method: EAP-pwd (RFC 5931)
   3  * Copyright (c) 2010, Dan Harkins <dharkins@lounge.org>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the BSD license.
   7  *
   8  * Alternatively, this software may be distributed under the terms of the
   9  * GNU General Public License version 2 as published by the Free Software
  10  * Foundation.
  11  *
  12  * See README and COPYING for more details.
  13  */
  14
  15 #include "includes.h"
  16
  17 #include "common.h"
  18 #include "eap_peer/eap_i.h"
  19 #include "eap_common/eap_pwd_common.h"
  20
  21
  22 struct eap_pwd_data {
  23         enum {
  24                 PWD_ID_Req, PWD_Commit_Req, PWD_Confirm_Req, SUCCESS, FAILURE
  25         } state;
  26         u8 *id_peer;
  27         size_t id_peer_len;
  28         u8 *id_server;
  29         size_t id_server_len;
  30         u8 *password;
  31         size_t password_len;
  32         u16 group_num;
  33         EAP_PWD_group *grp;
  34
  35         BIGNUM *k;
  36         BIGNUM *private_value;
  37         BIGNUM *server_scalar;
  38         BIGNUM *my_scalar;
  39         EC_POINT *my_element;
  40         EC_POINT *server_element;
  41
  42         u8 msk[EAP_MSK_LEN];
  43         u8 emsk[EAP_EMSK_LEN];
  44
  45         BN_CTX *bnctx;
  46 };
  47
  48
  49 #ifndef CONFIG_NO_STDOUT_DEBUG
  50 static const char * eap_pwd_state_txt(int state)
  51 {
  52         switch (state) {
  53         case PWD_ID_Req:
  54                 return "PWD-ID-Req";
  55         case PWD_Commit_Req:
  56                 return "PWD-Commit-Req";
  57         case PWD_Confirm_Req:
  58                 return "PWD-Confirm-Req";
  59         case SUCCESS:
  60                 return "SUCCESS";
  61         case FAILURE:
  62                 return "FAILURE";
  63         default:
  64                 return "PWD-UNK";
  65         }
  66 }
  67 #endif  /* CONFIG_NO_STDOUT_DEBUG */
  68
  69
  70 static void eap_pwd_state(struct eap_pwd_data *data, int state)
  71 {
  72         wpa_printf(MSG_INFO, "EAP-PWD: %s -> %s",
  73                    eap_pwd_state_txt(data->state), eap_pwd_state_txt(state));
  74         data->state = state;
  75 }
  76
  77
  78 static void * eap_pwd_init(struct eap_sm *sm)
  79 {
  80         struct eap_pwd_data *data;
  81         const u8 *identity, *password;
  82         size_t identity_len, password_len;
  83
  84         password = eap_get_config_password(sm, &password_len);
  85         if (password == NULL) {
  86                 wpa_printf(MSG_INFO, "EAP-PWD: No password configured!");
  87                 return NULL;
  88         }
  89
  90         identity = eap_get_config_identity(sm, &identity_len);
  91         if (identity == NULL) {
  92                 wpa_printf(MSG_INFO, "EAP-PWD: No identity configured!");
  93                 return NULL;
  94         }
  95
  96         if ((data = os_zalloc(sizeof(*data))) == NULL) {
  97                 wpa_printf(MSG_INFO, "EAP-PWD: memory allocation data fail");
  98                 return NULL;
  99         }
 100
 101         if ((data->bnctx = BN_CTX_new()) == NULL) {
 102                 wpa_printf(MSG_INFO, "EAP-PWD: bn context allocation fail");
 103                 os_free(data);
 104                 return NULL;
 105         }
 106
 107         if ((data->id_peer = os_malloc(identity_len)) == NULL) {
 108                 wpa_printf(MSG_INFO, "EAP-PWD: memory allocation id fail");
 109                 BN_CTX_free(data->bnctx);
 110                 os_free(data);
 111                 return NULL;
 112         }
 113
 114         os_memcpy(data->id_peer, identity, identity_len);
 115         data->id_peer_len = identity_len;
 116
 117         if ((data->password = os_malloc(password_len)) == NULL) {
 118                 wpa_printf(MSG_INFO, "EAP-PWD: memory allocation psk fail");
 119                 BN_CTX_free(data->bnctx);
 120                 os_free(data->id_peer);
 121                 os_free(data);
 122                 return NULL;
 123         }
 124         os_memcpy(data->password, password, password_len);
 125         data->password_len = password_len;
 126
 127         data->state = PWD_ID_Req;
 128
 129         return data;
 130 }
 131
 132
 133 static void eap_pwd_deinit(struct eap_sm *sm, void *priv)
 134 {
 135         struct eap_pwd_data *data = priv;
 136
 137         BN_free(data->private_value);
 138         BN_free(data->server_scalar);
 139         BN_free(data->my_scalar);
 140         BN_free(data->k);
 141         BN_CTX_free(data->bnctx);
 142         EC_POINT_free(data->my_element);
 143         EC_POINT_free(data->server_element);
 144         os_free(data->id_peer);
 145         os_free(data->id_server);
 146         os_free(data->password);
 147         if (data->grp) {
 148                 EC_GROUP_free(data->grp->group);
 149                 EC_POINT_free(data->grp->pwe);
 150                 BN_free(data->grp->order);
 151                 BN_free(data->grp->prime);
 152                 os_free(data->grp);
 153         }
 154         os_free(data);
 155 }
 156
 157
 158 static u8 * eap_pwd_getkey(struct eap_sm *sm, void *priv, size_t *len)
 159 {
 160         struct eap_pwd_data *data = priv;
 161         u8 *key;
 162
 163         if (data->state != SUCCESS)
 164                 return NULL;
 165
 166         key = os_malloc(EAP_MSK_LEN);
 167         if (key == NULL)
 168                 return NULL;
 169
 170         os_memcpy(key, data->msk, EAP_MSK_LEN);
 171         *len = EAP_MSK_LEN;
 172
 173         return key;
 174 }
 175
 176
 177 static struct wpabuf *
 178 eap_pwd_perform_id_exchange(struct eap_sm *sm, struct eap_pwd_data *data,
 179                             struct eap_method_ret *ret,
 180                             const struct wpabuf *reqData,
 181                             const u8 *payload, size_t payload_len)
 182 {
 183         struct eap_pwd_id *id;
 184         struct wpabuf *resp;
 185
 186         if (data->state != PWD_ID_Req) {
 187                 ret->ignore = TRUE;
 188                 return NULL;
 189         }
 190
 191         if (payload_len < sizeof(struct eap_pwd_id)) {
 192                 ret->ignore = TRUE;
 193                 return NULL;
 194         }
 195
 196         id = (struct eap_pwd_id *) payload;
 197         data->group_num = be_to_host16(id->group_num);
 198         if ((id->random_function != EAP_PWD_DEFAULT_RAND_FUNC) ||
 199             (id->prf != EAP_PWD_DEFAULT_PRF)) {
 200                 ret->ignore = TRUE;
 201                 return NULL;
 202         }
 203
 204         wpa_printf(MSG_DEBUG, "EAP-PWD (peer): server said group %d",
 205                    data->group_num);
 206
 207         data->id_server = os_malloc(payload_len - sizeof(struct eap_pwd_id));
 208         if (data->id_server == NULL) {
 209                 wpa_printf(MSG_INFO, "EAP-PWD: memory allocation id fail");
 210                 return NULL;
 211         }
 212         data->id_server_len = payload_len - sizeof(struct eap_pwd_id);
 213         os_memcpy(data->id_server, id->identity, data->id_server_len);
 214         wpa_hexdump_ascii(MSG_INFO, "EAP-PWD (peer): server sent id of",
 215                           data->id_server, data->id_server_len);
 216
 217         if ((data->grp = (EAP_PWD_group *) os_malloc(sizeof(EAP_PWD_group))) ==
 218             NULL) {
 219                 wpa_printf(MSG_INFO, "EAP-PWD: failed to allocate memory for "
 220                            "group");
 221                 return NULL;
 222         }
 223
 224         /* compute PWE */
 225         if (compute_password_element(data->grp, data->group_num,
 226                                      data->password, data->password_len,
 227                                      data->id_server, data->id_server_len,
 228                                      data->id_peer, data->id_peer_len,
 229                                      id->token)) {
 230                 wpa_printf(MSG_INFO, "EAP-PWD (peer): unable to compute PWE");
 231                 return NULL;
 232         }
 233
 234         wpa_printf(MSG_INFO, "EAP-PWD (peer): computed %d bit PWE...",
 235                    BN_num_bits(data->grp->prime));
 236
 237         resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD,
 238                              1 + sizeof(struct eap_pwd_id) + data->id_peer_len,
 239                              EAP_CODE_RESPONSE, eap_get_id(reqData));
 240         if (resp == NULL)
 241                 return NULL;
 242
 243         wpabuf_put_u8(resp, EAP_PWD_OPCODE_ID_EXCH);
 244         wpabuf_put_be16(resp, data->group_num);
 245         wpabuf_put_u8(resp, EAP_PWD_DEFAULT_RAND_FUNC);
 246         wpabuf_put_u8(resp, EAP_PWD_DEFAULT_PRF);
 247         wpabuf_put_data(resp, id->token, sizeof(id->token));
 248         wpabuf_put_u8(resp, EAP_PWD_PREP_NONE);
 249         wpabuf_put_data(resp, data->id_peer, data->id_peer_len);
 250
 251         eap_pwd_state(data, PWD_Commit_Req);
 252
 253         return resp;
 254 }
 255
 256
 257 static struct wpabuf *
 258 eap_pwd_perform_commit_exchange(struct eap_sm *sm, struct eap_pwd_data *data,
 259                                 struct eap_method_ret *ret,
 260                                 const struct wpabuf *reqData,
 261                                 const u8 *payload, size_t payload_len)
 262 {
 263         struct wpabuf *resp = NULL;
 264         EC_POINT *K = NULL, *point = NULL;
 265         BIGNUM *mask = NULL, *x = NULL, *y = NULL, *cofactor = NULL;
 266         u16 offset;
 267         u8 *ptr, *scalar = NULL, *element = NULL;
 268
 269         if (((data->private_value = BN_new()) == NULL) ||
 270             ((data->my_element = EC_POINT_new(data->grp->group)) == NULL) ||
 271             ((cofactor = BN_new()) == NULL) ||
 272             ((data->my_scalar = BN_new()) == NULL) ||
 273             ((mask = BN_new()) == NULL)) {
 274                 wpa_printf(MSG_INFO, "EAP-PWD (peer): scalar allocation fail");
 275                 goto fin;
 276         }
 277
 278         if (!EC_GROUP_get_cofactor(data->grp->group, cofactor, NULL)) {
 279                 wpa_printf(MSG_INFO, "EAP-pwd (peer): unable to get cofactor "
 280                            "for curve");
 281                 goto fin;
 282         }
 283
 284         BN_rand_range(data->private_value, data->grp->order);
 285         BN_rand_range(mask, data->grp->order);
 286         BN_add(data->my_scalar, data->private_value, mask);
 287         BN_mod(data->my_scalar, data->my_scalar, data->grp->order,
 288                data->bnctx);
 289
 290         if (!EC_POINT_mul(data->grp->group, data->my_element, NULL,
 291                           data->grp->pwe, mask, data->bnctx)) {
 292                 wpa_printf(MSG_INFO, "EAP-PWD (peer): element allocation "
 293                            "fail");
 294                 eap_pwd_state(data, FAILURE);
 295                 goto fin;
 296         }
 297
 298         if (!EC_POINT_invert(data->grp->group, data->my_element, data->bnctx))
 299         {
 300                 wpa_printf(MSG_INFO, "EAP-PWD (peer): element inversion fail");
 301                 goto fin;
 302         }
 303         BN_free(mask);
 304
 305         if (((x = BN_new()) == NULL) ||
 306             ((y = BN_new()) == NULL)) {
 307                 wpa_printf(MSG_INFO, "EAP-PWD (peer): point allocation fail");
 308                 goto fin;
 309         }
 310
 311         /* process the request */
 312         if (((data->server_scalar = BN_new()) == NULL) ||
 313             ((data->k = BN_new()) == NULL) ||
 314             ((K = EC_POINT_new(data->grp->group)) == NULL) ||
 315             ((point = EC_POINT_new(data->grp->group)) == NULL) ||
 316             ((data->server_element = EC_POINT_new(data->grp->group)) == NULL))
 317         {
 318                 wpa_printf(MSG_INFO, "EAP-PWD (peer): peer data allocation "
 319                            "fail");
 320                 goto fin;
 321         }
 322
 323         /* element, x then y, followed by scalar */
 324         ptr = (u8 *) payload;
 325         BN_bin2bn(ptr, BN_num_bytes(data->grp->prime), x);
 326         ptr += BN_num_bytes(data->grp->prime);
 327         BN_bin2bn(ptr, BN_num_bytes(data->grp->prime), y);
 328         ptr += BN_num_bytes(data->grp->prime);
 329         BN_bin2bn(ptr, BN_num_bytes(data->grp->order), data->server_scalar);
 330         if (!EC_POINT_set_affine_coordinates_GFp(data->grp->group,
 331                                                  data->server_element, x, y,
 332                                                  data->bnctx)) {
 333                 wpa_printf(MSG_INFO, "EAP-PWD (peer): setting peer element "
 334                            "fail");
 335                 goto fin;
 336         }
 337
 338         /* check to ensure server's element is not in a small sub-group */
 339         if (BN_cmp(cofactor, BN_value_one())) {
 340                 if (!EC_POINT_mul(data->grp->group, point, NULL,
 341                                   data->server_element, cofactor, NULL)) {
 342                         wpa_printf(MSG_INFO, "EAP-PWD (peer): cannot multiply "
 343                                    "server element by order!\n");
 344                         goto fin;
 345                 }
 346                 if (EC_POINT_is_at_infinity(data->grp->group, point)) {
 347                         wpa_printf(MSG_INFO, "EAP-PWD (peer): server element "
 348                                    "is at infinity!\n");
 349                         goto fin;
 350                 }
 351         }
 352
 353         /* compute the shared key, k */
 354         if ((!EC_POINT_mul(data->grp->group, K, NULL, data->grp->pwe,
 355                            data->server_scalar, data->bnctx)) ||
 356             (!EC_POINT_add(data->grp->group, K, K, data->server_element,
 357                            data->bnctx)) ||
 358             (!EC_POINT_mul(data->grp->group, K, NULL, K, data->private_value,
 359                            data->bnctx))) {
 360                 wpa_printf(MSG_INFO, "EAP-PWD (peer): computing shared key "
 361                            "fail");
 362                 goto fin;
 363         }
 364
 365         /* ensure that the shared key isn't in a small sub-group */
 366         if (BN_cmp(cofactor, BN_value_one())) {
 367                 if (!EC_POINT_mul(data->grp->group, K, NULL, K, cofactor,
 368                                   NULL)) {
 369                         wpa_printf(MSG_INFO, "EAP-PWD (peer): cannot multiply "
 370                                    "shared key point by order");
 371                         goto fin;
 372                 }
 373         }
 374
 375         /*
 376          * This check is strictly speaking just for the case above where
 377          * co-factor > 1 but it was suggested that even though this is probably
 378          * never going to happen it is a simple and safe check "just to be
 379          * sure" so let's be safe.
 380          */
 381         if (EC_POINT_is_at_infinity(data->grp->group, K)) {
 382                 wpa_printf(MSG_INFO, "EAP-PWD (peer): shared key point is at "
 383                            "infinity!\n");
 384                 goto fin;
 385         }
 386
 387         if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group, K, data->k,
 388                                                  NULL, data->bnctx)) {
 389                 wpa_printf(MSG_INFO, "EAP-PWD (peer): unable to extract "
 390                            "shared secret from point");
 391                 goto fin;
 392         }
 393
 394         /* now do the response */
 395         if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group,
 396                                                  data->my_element, x, y,
 397                                                  data->bnctx)) {
 398                 wpa_printf(MSG_INFO, "EAP-PWD (peer): point assignment fail");
 399                 goto fin;
 400         }
 401
 402         if (((scalar = os_malloc(BN_num_bytes(data->grp->order))) == NULL) ||
 403             ((element = os_malloc(BN_num_bytes(data->grp->prime) * 2)) ==
 404              NULL)) {
 405                 wpa_printf(MSG_INFO, "EAP-PWD (peer): data allocation fail");
 406                 goto fin;
 407         }
 408
 409         /*
 410          * bignums occupy as little memory as possible so one that is
 411          * sufficiently smaller than the prime or order might need pre-pending
 412          * with zeros.
 413          */
 414         os_memset(scalar, 0, BN_num_bytes(data->grp->order));
 415         os_memset(element, 0, BN_num_bytes(data->grp->prime) * 2);
 416         offset = BN_num_bytes(data->grp->order) -
 417                 BN_num_bytes(data->my_scalar);
 418         BN_bn2bin(data->my_scalar, scalar + offset);
 419
 420         offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(x);
 421         BN_bn2bin(x, element + offset);
 422         offset = BN_num_bytes(data->grp->prime) - BN_num_bytes(y);
 423         BN_bn2bin(y, element + BN_num_bytes(data->grp->prime) + offset);
 424
 425         resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD,
 426                              sizeof(struct eap_pwd_hdr) +
 427                              BN_num_bytes(data->grp->order) +
 428                              (2 * BN_num_bytes(data->grp->prime)),
 429                              EAP_CODE_RESPONSE, eap_get_id(reqData));
 430         if (resp == NULL)
 431                 goto fin;
 432
 433         wpabuf_put_u8(resp, EAP_PWD_OPCODE_COMMIT_EXCH);
 434
 435         /* we send the element as (x,y) follwed by the scalar */
 436         wpabuf_put_data(resp, element, (2 * BN_num_bytes(data->grp->prime)));
 437         wpabuf_put_data(resp, scalar, BN_num_bytes(data->grp->order));
 438
 439 fin:
 440         os_free(scalar);
 441         os_free(element);
 442         BN_free(x);
 443         BN_free(y);
 444         BN_free(cofactor);
 445         EC_POINT_free(K);
 446         EC_POINT_free(point);
 447         if (resp == NULL)
 448                 eap_pwd_state(data, FAILURE);
 449         else
 450                 eap_pwd_state(data, PWD_Confirm_Req);
 451
 452         return resp;
 453 }
 454
 455
 456 static struct wpabuf *
 457 eap_pwd_perform_confirm_exchange(struct eap_sm *sm, struct eap_pwd_data *data,
 458                                  struct eap_method_ret *ret,
 459                                  const struct wpabuf *reqData,
 460                                  const u8 *payload, size_t payload_len)
 461 {
 462         struct wpabuf *resp = NULL;
 463         BIGNUM *x = NULL, *y = NULL;
 464         HMAC_CTX ctx;
 465         u32 cs;
 466         u8 conf[SHA256_DIGEST_LENGTH], *cruft = NULL, *ptr;
 467
 468         /*
 469          * first build up the ciphersuite which is group | random_function |
 470          *      prf
 471          */
 472         ptr = (u8 *) &cs;
 473         os_memcpy(ptr, &data->group_num, sizeof(u16));
 474         ptr += sizeof(u16);
 475         *ptr = EAP_PWD_DEFAULT_RAND_FUNC;
 476         ptr += sizeof(u8);
 477         *ptr = EAP_PWD_DEFAULT_PRF;
 478
 479         /* each component of the cruft will be at most as big as the prime */
 480         if (((cruft = os_malloc(BN_num_bytes(data->grp->prime))) == NULL) ||
 481             ((x = BN_new()) == NULL) || ((y = BN_new()) == NULL)) {
 482                 wpa_printf(MSG_INFO, "EAP-PWD (server): debug allocation "
 483                            "fail");
 484                 goto fin;
 485         }
 486
 487         /*
 488          * server's commit is H(k | server_element | server_scalar |
 489          *                      peer_element | peer_scalar | ciphersuite)
 490          */
 491         H_Init(&ctx);
 492
 493         /*
 494          * zero the memory each time because this is mod prime math and some
 495          * value may start with a few zeros and the previous one did not.
 496          */
 497         os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
 498         BN_bn2bin(data->k, cruft);
 499         H_Update(&ctx, cruft, BN_num_bytes(data->grp->prime));
 500
 501         /* server element: x, y */
 502         if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group,
 503                                                  data->server_element, x, y,
 504                                                  data->bnctx)) {
 505                 wpa_printf(MSG_INFO, "EAP-PWD (server): confirm point "
 506                            "assignment fail");
 507                 goto fin;
 508         }
 509         os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
 510         BN_bn2bin(x, cruft);
 511         H_Update(&ctx, cruft, BN_num_bytes(data->grp->prime));
 512         os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
 513         BN_bn2bin(y, cruft);
 514         H_Update(&ctx, cruft, BN_num_bytes(data->grp->prime));
 515
 516         /* server scalar */
 517         os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
 518         BN_bn2bin(data->server_scalar, cruft);
 519         H_Update(&ctx, cruft, BN_num_bytes(data->grp->order));
 520
 521         /* my element: x, y */
 522         if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group,
 523                                                  data->my_element, x, y,
 524                                                  data->bnctx)) {
 525                 wpa_printf(MSG_INFO, "EAP-PWD (server): confirm point "
 526                            "assignment fail");
 527                 goto fin;
 528         }
 529
 530         os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
 531         BN_bn2bin(x, cruft);
 532         H_Update(&ctx, cruft, BN_num_bytes(data->grp->prime));
 533         os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
 534         BN_bn2bin(y, cruft);
 535         H_Update(&ctx, cruft, BN_num_bytes(data->grp->prime));
 536
 537         /* my scalar */
 538         os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
 539         BN_bn2bin(data->my_scalar, cruft);
 540         H_Update(&ctx, cruft, BN_num_bytes(data->grp->order));
 541
 542         /* the ciphersuite */
 543         H_Update(&ctx, (u8 *) &cs, sizeof(u32));
 544
 545         /* random function fin */
 546         H_Final(&ctx, conf);
 547
 548         ptr = (u8 *) payload;
 549         if (os_memcmp(conf, ptr, SHA256_DIGEST_LENGTH)) {
 550                 wpa_printf(MSG_INFO, "EAP-PWD (peer): confirm did not verify");
 551                 goto fin;
 552         }
 553
 554         wpa_printf(MSG_DEBUG, "EAP-pwd (peer): confirm verified");
 555
 556         /*
 557          * compute confirm:
 558          *  H(k | peer_element | peer_scalar | server_element | server_scalar |
 559          *    ciphersuite)
 560          */
 561         H_Init(&ctx);
 562
 563         /* k */
 564         os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
 565         BN_bn2bin(data->k, cruft);
 566         H_Update(&ctx, cruft, BN_num_bytes(data->grp->prime));
 567
 568         /* my element */
 569         if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group,
 570                                                  data->my_element, x, y,
 571                                                  data->bnctx)) {
 572                 wpa_printf(MSG_INFO, "EAP-PWD (peer): confirm point "
 573                            "assignment fail");
 574                 goto fin;
 575         }
 576         os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
 577         BN_bn2bin(x, cruft);
 578         H_Update(&ctx, cruft, BN_num_bytes(data->grp->prime));
 579         os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
 580         BN_bn2bin(y, cruft);
 581         H_Update(&ctx, cruft, BN_num_bytes(data->grp->prime));
 582
 583         /* my scalar */
 584         os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
 585         BN_bn2bin(data->my_scalar, cruft);
 586         H_Update(&ctx, cruft, BN_num_bytes(data->grp->order));
 587
 588         /* server element: x, y */
 589         if (!EC_POINT_get_affine_coordinates_GFp(data->grp->group,
 590                                                  data->server_element, x, y,
 591                                                  data->bnctx)) {
 592                 wpa_printf(MSG_INFO, "EAP-PWD (peer): confirm point "
 593                            "assignment fail");
 594                 goto fin;
 595         }
 596         os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
 597         BN_bn2bin(x, cruft);
 598         H_Update(&ctx, cruft, BN_num_bytes(data->grp->prime));
 599         os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
 600         BN_bn2bin(y, cruft);
 601         H_Update(&ctx, cruft, BN_num_bytes(data->grp->prime));
 602
 603         /* server scalar */
 604         os_memset(cruft, 0, BN_num_bytes(data->grp->prime));
 605         BN_bn2bin(data->server_scalar, cruft);
 606         H_Update(&ctx, cruft, BN_num_bytes(data->grp->order));
 607
 608         /* the ciphersuite */
 609         H_Update(&ctx, (u8 *) &cs, sizeof(u32));
 610
 611         /* all done */
 612         H_Final(&ctx, conf);
 613
 614         resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PWD,
 615                              sizeof(struct eap_pwd_hdr) + SHA256_DIGEST_LENGTH,
 616                              EAP_CODE_RESPONSE, eap_get_id(reqData));
 617         if (resp == NULL)
 618                 goto fin;
 619
 620         wpabuf_put_u8(resp, EAP_PWD_OPCODE_CONFIRM_EXCH);
 621         wpabuf_put_data(resp, conf, SHA256_DIGEST_LENGTH);
 622
 623         if (compute_keys(data->grp, data->bnctx, data->k, data->server_element,
 624                          data->my_element, data->server_scalar,
 625                          data->my_scalar, &cs, data->msk, data->emsk) < 0) {
 626                 wpa_printf(MSG_INFO, "EAP-PWD (peer): unable to compute MSK | "
 627                            "EMSK");
 628                 goto fin;
 629         }
 630
 631 fin:
 632         os_free(cruft);
 633         BN_free(x);
 634         BN_free(y);
 635         ret->methodState = METHOD_DONE;
 636         if (resp == NULL) {
 637                 ret->decision = DECISION_FAIL;
 638                 eap_pwd_state(data, FAILURE);
 639         } else {
 640                 ret->decision = DECISION_UNCOND_SUCC;
 641                 eap_pwd_state(data, SUCCESS);
 642         }
 643
 644         return resp;
 645 }
 646
 647
 648 static struct wpabuf *
 649 eap_pwd_process(struct eap_sm *sm, void *priv, struct eap_method_ret *ret,
 650                 const struct wpabuf *reqData)
 651 {
 652         struct eap_pwd_data *data = priv;
 653         struct wpabuf *resp = NULL;
 654         const u8 *pos;
 655         size_t len;
 656         u8 exch;
 657
 658         pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PWD, reqData, &len);
 659         if ((pos == NULL) || (len < 1)) {
 660                 ret->ignore = TRUE;
 661                 return NULL;
 662         }
 663
 664         wpa_printf(MSG_INFO, "EAP-pwd: Received frame: opcode %d", *pos);
 665
 666         ret->ignore = FALSE;
 667         ret->methodState = METHOD_MAY_CONT;
 668         ret->decision = DECISION_FAIL;
 669         ret->allowNotifications = FALSE;
 670
 671         exch = *pos & 0x3f;
 672         switch (exch) {
 673         case EAP_PWD_OPCODE_ID_EXCH:
 674                 resp = eap_pwd_perform_id_exchange(sm, data, ret, reqData,
 675                                                    pos + 1, len - 1);
 676                 break;
 677         case EAP_PWD_OPCODE_COMMIT_EXCH:
 678                 resp = eap_pwd_perform_commit_exchange(sm, data, ret, reqData,
 679                                                        pos + 1, len - 1);
 680                 break;
 681         case EAP_PWD_OPCODE_CONFIRM_EXCH:
 682                 resp = eap_pwd_perform_confirm_exchange(sm, data, ret, reqData,
 683                                                         pos + 1, len - 1);
 684                 break;
 685         default:
 686                 wpa_printf(MSG_INFO, "EAP-pwd: Ignoring message with unknown "
 687                            "opcode %d", exch);
 688                 break;
 689         }
 690
 691         return resp;
 692 }
 693
 694
 695 static Boolean eap_pwd_key_available(struct eap_sm *sm, void *priv)
 696 {
 697         struct eap_pwd_data *data = priv;
 698         return data->state == SUCCESS;
 699 }
 700
 701
 702 static u8 * eap_pwd_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
 703 {
 704         struct eap_pwd_data *data = priv;
 705         u8 *key;
 706
 707         if (data->state != SUCCESS)
 708                 return NULL;
 709
 710         if ((key = os_malloc(EAP_EMSK_LEN)) == NULL)
 711                 return NULL;
 712
 713         os_memcpy(key, data->emsk, EAP_EMSK_LEN);
 714         *len = EAP_EMSK_LEN;
 715
 716         return key;
 717 }
 718
 719
 720 int eap_peer_pwd_register(void)
 721 {
 722         struct eap_method *eap;
 723         int ret;
 724
 725         EVP_add_digest(EVP_sha256());
 726         eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
 727                                     EAP_VENDOR_IETF, EAP_TYPE_PWD, "PWD");
 728         if (eap == NULL)
 729                 return -1;
 730
 731         eap->init = eap_pwd_init;
 732         eap->deinit = eap_pwd_deinit;
 733         eap->process = eap_pwd_process;
 734         eap->isKeyAvailable = eap_pwd_key_available;
 735         eap->getKey = eap_pwd_getkey;
 736         eap->get_emsk = eap_pwd_get_emsk;
 737
 738         ret = eap_peer_method_register(eap);
 739         if (ret)
 740                 eap_peer_method_free(eap);
 741         return ret;
 742 }