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