libeap/src/eap_peer/eap_ikev2.c

   1 /*
   2  * EAP-IKEv2 peer (RFC 5106)
   3  * Copyright (c) 2007-2014, 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 "eap_i.h"
  13 #include "eap_common/eap_ikev2_common.h"
  14 #include "ikev2.h"
  15
  16
  17 struct eap_ikev2_data {
  18         struct ikev2_responder_data ikev2;
  19         enum { WAIT_START, PROC_MSG, WAIT_FRAG_ACK, DONE, FAIL } state;
  20         struct wpabuf *in_buf;
  21         struct wpabuf *out_buf;
  22         size_t out_used;
  23         size_t fragment_size;
  24         int keys_ready;
  25         u8 keymat[EAP_MSK_LEN + EAP_EMSK_LEN];
  26         int keymat_ok;
  27 };
  28
  29
  30 static const char * eap_ikev2_state_txt(int state)
  31 {
  32         switch (state) {
  33         case WAIT_START:
  34                 return "WAIT_START";
  35         case PROC_MSG:
  36                 return "PROC_MSG";
  37         case WAIT_FRAG_ACK:
  38                 return "WAIT_FRAG_ACK";
  39         case DONE:
  40                 return "DONE";
  41         case FAIL:
  42                 return "FAIL";
  43         default:
  44                 return "?";
  45         }
  46 }
  47
  48
  49 static void eap_ikev2_state(struct eap_ikev2_data *data, int state)
  50 {
  51         wpa_printf(MSG_DEBUG, "EAP-IKEV2: %s -> %s",
  52                    eap_ikev2_state_txt(data->state),
  53                    eap_ikev2_state_txt(state));
  54         data->state = state;
  55 }
  56
  57
  58 static void * eap_ikev2_init(struct eap_sm *sm)
  59 {
  60         struct eap_ikev2_data *data;
  61         const u8 *identity, *password;
  62         size_t identity_len, password_len;
  63         int fragment_size;
  64
  65         identity = eap_get_config_identity(sm, &identity_len);
  66         if (identity == NULL) {
  67                 wpa_printf(MSG_INFO, "EAP-IKEV2: No identity available");
  68                 return NULL;
  69         }
  70
  71         data = os_zalloc(sizeof(*data));
  72         if (data == NULL)
  73                 return NULL;
  74         data->state = WAIT_START;
  75         fragment_size = eap_get_config_fragment_size(sm);
  76         if (fragment_size <= 0)
  77                 data->fragment_size = IKEV2_FRAGMENT_SIZE;
  78         else
  79                 data->fragment_size = fragment_size;
  80         data->ikev2.state = SA_INIT;
  81         data->ikev2.peer_auth = PEER_AUTH_SECRET;
  82         data->ikev2.key_pad = (u8 *) os_strdup("Key Pad for EAP-IKEv2");
  83         if (data->ikev2.key_pad == NULL)
  84                 goto failed;
  85         data->ikev2.key_pad_len = 21;
  86         data->ikev2.IDr = os_malloc(identity_len);
  87         if (data->ikev2.IDr == NULL)
  88                 goto failed;
  89         os_memcpy(data->ikev2.IDr, identity, identity_len);
  90         data->ikev2.IDr_len = identity_len;
  91
  92         password = eap_get_config_password(sm, &password_len);
  93         if (password) {
  94                 data->ikev2.shared_secret = os_malloc(password_len);
  95                 if (data->ikev2.shared_secret == NULL)
  96                         goto failed;
  97                 os_memcpy(data->ikev2.shared_secret, password, password_len);
  98                 data->ikev2.shared_secret_len = password_len;
  99         }
 100
 101         return data;
 102
 103 failed:
 104         ikev2_responder_deinit(&data->ikev2);
 105         os_free(data);
 106         return NULL;
 107 }
 108
 109
 110 static void eap_ikev2_deinit(struct eap_sm *sm, void *priv)
 111 {
 112         struct eap_ikev2_data *data = priv;
 113         wpabuf_free(data->in_buf);
 114         wpabuf_free(data->out_buf);
 115         ikev2_responder_deinit(&data->ikev2);
 116         bin_clear_free(data, sizeof(*data));
 117 }
 118
 119
 120 static int eap_ikev2_peer_keymat(struct eap_ikev2_data *data)
 121 {
 122         if (eap_ikev2_derive_keymat(
 123                     data->ikev2.proposal.prf, &data->ikev2.keys,
 124                     data->ikev2.i_nonce, data->ikev2.i_nonce_len,
 125                     data->ikev2.r_nonce, data->ikev2.r_nonce_len,
 126                     data->keymat) < 0) {
 127                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Failed to "
 128                            "derive key material");
 129                 return -1;
 130         }
 131         data->keymat_ok = 1;
 132         return 0;
 133 }
 134
 135
 136 static struct wpabuf * eap_ikev2_build_msg(struct eap_ikev2_data *data,
 137                                            struct eap_method_ret *ret, u8 id)
 138 {
 139         struct wpabuf *resp;
 140         u8 flags;
 141         size_t send_len, plen, icv_len = 0;
 142
 143         ret->ignore = FALSE;
 144         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Generating Response");
 145         ret->allowNotifications = TRUE;
 146
 147         flags = 0;
 148         send_len = wpabuf_len(data->out_buf) - data->out_used;
 149         if (1 + send_len > data->fragment_size) {
 150                 send_len = data->fragment_size - 1;
 151                 flags |= IKEV2_FLAGS_MORE_FRAGMENTS;
 152                 if (data->out_used == 0) {
 153                         flags |= IKEV2_FLAGS_LENGTH_INCLUDED;
 154                         send_len -= 4;
 155                 }
 156         }
 157
 158         plen = 1 + send_len;
 159         if (flags & IKEV2_FLAGS_LENGTH_INCLUDED)
 160                 plen += 4;
 161         if (data->keys_ready) {
 162                 const struct ikev2_integ_alg *integ;
 163                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Add Integrity Checksum "
 164                            "Data");
 165                 flags |= IKEV2_FLAGS_ICV_INCLUDED;
 166                 integ = ikev2_get_integ(data->ikev2.proposal.integ);
 167                 if (integ == NULL) {
 168                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Unknown INTEG "
 169                                    "transform / cannot generate ICV");
 170                         return NULL;
 171                 }
 172                 icv_len = integ->hash_len;
 173
 174                 plen += icv_len;
 175         }
 176         resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_IKEV2, plen,
 177                              EAP_CODE_RESPONSE, id);
 178         if (resp == NULL)
 179                 return NULL;
 180
 181         wpabuf_put_u8(resp, flags); /* Flags */
 182         if (flags & IKEV2_FLAGS_LENGTH_INCLUDED)
 183                 wpabuf_put_be32(resp, wpabuf_len(data->out_buf));
 184
 185         wpabuf_put_data(resp, wpabuf_head_u8(data->out_buf) + data->out_used,
 186                         send_len);
 187         data->out_used += send_len;
 188
 189         if (flags & IKEV2_FLAGS_ICV_INCLUDED) {
 190                 const u8 *msg = wpabuf_head(resp);
 191                 size_t len = wpabuf_len(resp);
 192                 ikev2_integ_hash(data->ikev2.proposal.integ,
 193                                  data->ikev2.keys.SK_ar,
 194                                  data->ikev2.keys.SK_integ_len,
 195                                  msg, len, wpabuf_put(resp, icv_len));
 196         }
 197
 198         ret->methodState = METHOD_MAY_CONT;
 199         ret->decision = DECISION_FAIL;
 200
 201         if (data->out_used == wpabuf_len(data->out_buf)) {
 202                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Sending out %lu bytes "
 203                            "(message sent completely)",
 204                            (unsigned long) send_len);
 205                 wpabuf_free(data->out_buf);
 206                 data->out_buf = NULL;
 207                 data->out_used = 0;
 208                 switch (data->ikev2.state) {
 209                 case SA_AUTH:
 210                         /* SA_INIT was sent out, so message have to be
 211                          * integrity protected from now on. */
 212                         data->keys_ready = 1;
 213                         break;
 214                 case IKEV2_DONE:
 215                         ret->methodState = METHOD_DONE;
 216                         if (data->state == FAIL)
 217                                 break;
 218                         ret->decision = DECISION_COND_SUCC;
 219                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Authentication "
 220                                    "completed successfully");
 221                         if (eap_ikev2_peer_keymat(data))
 222                                 break;
 223                         eap_ikev2_state(data, DONE);
 224                         break;
 225                 case IKEV2_FAILED:
 226                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Authentication "
 227                                    "failed");
 228                         ret->methodState = METHOD_DONE;
 229                         ret->decision = DECISION_FAIL;
 230                         break;
 231                 default:
 232                         break;
 233                 }
 234         } else {
 235                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Sending out %lu bytes "
 236                            "(%lu more to send)", (unsigned long) send_len,
 237                            (unsigned long) wpabuf_len(data->out_buf) -
 238                            data->out_used);
 239                 eap_ikev2_state(data, WAIT_FRAG_ACK);
 240         }
 241
 242         return resp;
 243 }
 244
 245
 246 static int eap_ikev2_process_icv(struct eap_ikev2_data *data,
 247                                  const struct wpabuf *reqData,
 248                                  u8 flags, const u8 *pos, const u8 **end,
 249                                  int frag_ack)
 250 {
 251         if (flags & IKEV2_FLAGS_ICV_INCLUDED) {
 252                 int icv_len = eap_ikev2_validate_icv(
 253                         data->ikev2.proposal.integ, &data->ikev2.keys, 1,
 254                         reqData, pos, *end);
 255                 if (icv_len < 0)
 256                         return -1;
 257                 /* Hide Integrity Checksum Data from further processing */
 258                 *end -= icv_len;
 259         } else if (data->keys_ready && !frag_ack) {
 260                 wpa_printf(MSG_INFO, "EAP-IKEV2: The message should have "
 261                            "included integrity checksum");
 262                 return -1;
 263         }
 264
 265         return 0;
 266 }
 267
 268
 269 static int eap_ikev2_process_cont(struct eap_ikev2_data *data,
 270                                   const u8 *buf, size_t len)
 271 {
 272         /* Process continuation of a pending message */
 273         if (len > wpabuf_tailroom(data->in_buf)) {
 274                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Fragment overflow");
 275                 eap_ikev2_state(data, FAIL);
 276                 return -1;
 277         }
 278
 279         wpabuf_put_data(data->in_buf, buf, len);
 280         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Received %lu bytes, waiting "
 281                    "for %lu bytes more", (unsigned long) len,
 282                    (unsigned long) wpabuf_tailroom(data->in_buf));
 283
 284         return 0;
 285 }
 286
 287
 288 static struct wpabuf * eap_ikev2_process_fragment(struct eap_ikev2_data *data,
 289                                                   struct eap_method_ret *ret,
 290                                                   u8 id, u8 flags,
 291                                                   u32 message_length,
 292                                                   const u8 *buf, size_t len)
 293 {
 294         /* Process a fragment that is not the last one of the message */
 295         if (data->in_buf == NULL && !(flags & IKEV2_FLAGS_LENGTH_INCLUDED)) {
 296                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: No Message Length field in "
 297                            "a fragmented packet");
 298                 ret->ignore = TRUE;
 299                 return NULL;
 300         }
 301
 302         if (data->in_buf == NULL) {
 303                 /* First fragment of the message */
 304                 if (message_length > 50000) {
 305                         /* Limit maximum memory allocation */
 306                         wpa_printf(MSG_DEBUG,
 307                                    "EAP-IKEV2: Ignore too long message");
 308                         ret->ignore = TRUE;
 309                         return NULL;
 310                 }
 311                 data->in_buf = wpabuf_alloc(message_length);
 312                 if (data->in_buf == NULL) {
 313                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: No memory for "
 314                                    "message");
 315                         ret->ignore = TRUE;
 316                         return NULL;
 317                 }
 318                 wpabuf_put_data(data->in_buf, buf, len);
 319                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Received %lu bytes in first "
 320                            "fragment, waiting for %lu bytes more",
 321                            (unsigned long) len,
 322                            (unsigned long) wpabuf_tailroom(data->in_buf));
 323         }
 324
 325         ret->ignore = FALSE;
 326         return eap_ikev2_build_frag_ack(id, EAP_CODE_RESPONSE);
 327 }
 328
 329
 330 static struct wpabuf * eap_ikev2_process(struct eap_sm *sm, void *priv,
 331                                          struct eap_method_ret *ret,
 332                                          const struct wpabuf *reqData)
 333 {
 334         struct eap_ikev2_data *data = priv;
 335         const u8 *start, *pos, *end;
 336         size_t len;
 337         u8 flags, id;
 338         u32 message_length = 0;
 339         struct wpabuf tmpbuf;
 340
 341         pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_IKEV2, reqData, &len);
 342         if (pos == NULL) {
 343                 ret->ignore = TRUE;
 344                 return NULL;
 345         }
 346
 347         id = eap_get_id(reqData);
 348
 349         start = pos;
 350         end = start + len;
 351
 352         if (len == 0)
 353                 flags = 0; /* fragment ack */
 354         else
 355                 flags = *pos++;
 356
 357         if (eap_ikev2_process_icv(data, reqData, flags, pos, &end,
 358                                   data->state == WAIT_FRAG_ACK && len == 0) < 0)
 359         {
 360                 ret->ignore = TRUE;
 361                 return NULL;
 362         }
 363
 364         if (flags & IKEV2_FLAGS_LENGTH_INCLUDED) {
 365                 if (end - pos < 4) {
 366                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Message underflow");
 367                         ret->ignore = TRUE;
 368                         return NULL;
 369                 }
 370                 message_length = WPA_GET_BE32(pos);
 371                 pos += 4;
 372
 373                 if (message_length < (u32) (end - pos)) {
 374                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Invalid Message "
 375                                    "Length (%d; %ld remaining in this msg)",
 376                                    message_length, (long) (end - pos));
 377                         ret->ignore = TRUE;
 378                         return NULL;
 379                 }
 380         }
 381
 382         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Received packet: Flags 0x%x "
 383                    "Message Length %u", flags, message_length);
 384
 385         if (data->state == WAIT_FRAG_ACK) {
 386                 if (len != 0) {
 387                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Unexpected payload "
 388                                    "in WAIT_FRAG_ACK state");
 389                         ret->ignore = TRUE;
 390                         return NULL;
 391                 }
 392                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Fragment acknowledged");
 393                 eap_ikev2_state(data, PROC_MSG);
 394                 return eap_ikev2_build_msg(data, ret, id);
 395         }
 396
 397         if (data->in_buf && eap_ikev2_process_cont(data, pos, end - pos) < 0) {
 398                 ret->ignore = TRUE;
 399                 return NULL;
 400         }
 401
 402         if (flags & IKEV2_FLAGS_MORE_FRAGMENTS) {
 403                 return eap_ikev2_process_fragment(data, ret, id, flags,
 404                                                   message_length, pos,
 405                                                   end - pos);
 406         }
 407
 408         if (data->in_buf == NULL) {
 409                 /* Wrap unfragmented messages as wpabuf without extra copy */
 410                 wpabuf_set(&tmpbuf, pos, end - pos);
 411                 data->in_buf = &tmpbuf;
 412         }
 413
 414         if (ikev2_responder_process(&data->ikev2, data->in_buf) < 0) {
 415                 if (data->in_buf == &tmpbuf)
 416                         data->in_buf = NULL;
 417                 eap_ikev2_state(data, FAIL);
 418                 return NULL;
 419         }
 420
 421         if (data->in_buf != &tmpbuf)
 422                 wpabuf_free(data->in_buf);
 423         data->in_buf = NULL;
 424
 425         if (data->out_buf == NULL) {
 426                 data->out_buf = ikev2_responder_build(&data->ikev2);
 427                 if (data->out_buf == NULL) {
 428                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Failed to generate "
 429                                    "IKEv2 message");
 430                         return NULL;
 431                 }
 432                 data->out_used = 0;
 433         }
 434
 435         eap_ikev2_state(data, PROC_MSG);
 436         return eap_ikev2_build_msg(data, ret, id);
 437 }
 438
 439
 440 static Boolean eap_ikev2_isKeyAvailable(struct eap_sm *sm, void *priv)
 441 {
 442         struct eap_ikev2_data *data = priv;
 443         return data->state == DONE && data->keymat_ok;
 444 }
 445
 446
 447 static u8 * eap_ikev2_getKey(struct eap_sm *sm, void *priv, size_t *len)
 448 {
 449         struct eap_ikev2_data *data = priv;
 450         u8 *key;
 451
 452         if (data->state != DONE || !data->keymat_ok)
 453                 return NULL;
 454
 455         key = os_malloc(EAP_MSK_LEN);
 456         if (key) {
 457                 os_memcpy(key, data->keymat, EAP_MSK_LEN);
 458                 *len = EAP_MSK_LEN;
 459         }
 460
 461         return key;
 462 }
 463
 464
 465 static u8 * eap_ikev2_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
 466 {
 467         struct eap_ikev2_data *data = priv;
 468         u8 *key;
 469
 470         if (data->state != DONE || !data->keymat_ok)
 471                 return NULL;
 472
 473         key = os_malloc(EAP_EMSK_LEN);
 474         if (key) {
 475                 os_memcpy(key, data->keymat + EAP_MSK_LEN, EAP_EMSK_LEN);
 476                 *len = EAP_EMSK_LEN;
 477         }
 478
 479         return key;
 480 }
 481
 482
 483 static u8 * eap_ikev2_get_session_id(struct eap_sm *sm, void *priv, size_t *len)
 484 {
 485         struct eap_ikev2_data *data = priv;
 486         u8 *sid;
 487         size_t sid_len;
 488         size_t offset;
 489
 490         if (data->state != DONE || !data->keymat_ok)
 491                 return NULL;
 492
 493         sid_len = 1 + data->ikev2.i_nonce_len + data->ikev2.r_nonce_len;
 494         sid = os_malloc(sid_len);
 495         if (sid) {
 496                 offset = 0;
 497                 sid[offset] = EAP_TYPE_IKEV2;
 498                 offset++;
 499                 os_memcpy(sid + offset, data->ikev2.i_nonce,
 500                           data->ikev2.i_nonce_len);
 501                 offset += data->ikev2.i_nonce_len;
 502                 os_memcpy(sid + offset, data->ikev2.r_nonce,
 503                           data->ikev2.r_nonce_len);
 504                 *len = sid_len;
 505                 wpa_hexdump(MSG_DEBUG, "EAP-IKEV2: Derived Session-Id",
 506                             sid, sid_len);
 507         }
 508
 509         return sid;
 510 }
 511
 512
 513 int eap_peer_ikev2_register(void)
 514 {
 515         struct eap_method *eap;
 516         int ret;
 517
 518         eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
 519                                     EAP_VENDOR_IETF, EAP_TYPE_IKEV2,
 520                                     "IKEV2");
 521         if (eap == NULL)
 522                 return -1;
 523
 524         eap->init = eap_ikev2_init;
 525         eap->deinit = eap_ikev2_deinit;
 526         eap->process = eap_ikev2_process;
 527         eap->isKeyAvailable = eap_ikev2_isKeyAvailable;
 528         eap->getKey = eap_ikev2_getKey;
 529         eap->get_emsk = eap_ikev2_get_emsk;
 530         eap->getSessionId = eap_ikev2_get_session_id;
 531
 532         ret = eap_peer_method_register(eap);
 533         if (ret)
 534                 eap_peer_method_free(eap);
 535         return ret;
 536 }