contrib/wpa/src/eap_peer/eap_ikev2.c

   1 /*
   2  * EAP-IKEv2 peer (RFC 5106)
   3  * Copyright (c) 2007, 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
  64         identity = eap_get_config_identity(sm, &identity_len);
  65         if (identity == NULL) {
  66                 wpa_printf(MSG_INFO, "EAP-IKEV2: No identity available");
  67                 return NULL;
  68         }
  69
  70         data = os_zalloc(sizeof(*data));
  71         if (data == NULL)
  72                 return NULL;
  73         data->state = WAIT_START;
  74         data->fragment_size = IKEV2_FRAGMENT_SIZE;
  75         data->ikev2.state = SA_INIT;
  76         data->ikev2.peer_auth = PEER_AUTH_SECRET;
  77         data->ikev2.key_pad = (u8 *) os_strdup("Key Pad for EAP-IKEv2");
  78         if (data->ikev2.key_pad == NULL)
  79                 goto failed;
  80         data->ikev2.key_pad_len = 21;
  81         data->ikev2.IDr = os_malloc(identity_len);
  82         if (data->ikev2.IDr == NULL)
  83                 goto failed;
  84         os_memcpy(data->ikev2.IDr, identity, identity_len);
  85         data->ikev2.IDr_len = identity_len;
  86
  87         password = eap_get_config_password(sm, &password_len);
  88         if (password) {
  89                 data->ikev2.shared_secret = os_malloc(password_len);
  90                 if (data->ikev2.shared_secret == NULL)
  91                         goto failed;
  92                 os_memcpy(data->ikev2.shared_secret, password, password_len);
  93                 data->ikev2.shared_secret_len = password_len;
  94         }
  95
  96         return data;
  97
  98 failed:
  99         ikev2_responder_deinit(&data->ikev2);
 100         os_free(data);
 101         return NULL;
 102 }
 103
 104
 105 static void eap_ikev2_deinit(struct eap_sm *sm, void *priv)
 106 {
 107         struct eap_ikev2_data *data = priv;
 108         wpabuf_free(data->in_buf);
 109         wpabuf_free(data->out_buf);
 110         ikev2_responder_deinit(&data->ikev2);
 111         os_free(data);
 112 }
 113
 114
 115 static int eap_ikev2_peer_keymat(struct eap_ikev2_data *data)
 116 {
 117         if (eap_ikev2_derive_keymat(
 118                     data->ikev2.proposal.prf, &data->ikev2.keys,
 119                     data->ikev2.i_nonce, data->ikev2.i_nonce_len,
 120                     data->ikev2.r_nonce, data->ikev2.r_nonce_len,
 121                     data->keymat) < 0) {
 122                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Failed to "
 123                            "derive key material");
 124                 return -1;
 125         }
 126         data->keymat_ok = 1;
 127         return 0;
 128 }
 129
 130
 131 static struct wpabuf * eap_ikev2_build_msg(struct eap_ikev2_data *data,
 132                                            struct eap_method_ret *ret, u8 id)
 133 {
 134         struct wpabuf *resp;
 135         u8 flags;
 136         size_t send_len, plen, icv_len = 0;
 137
 138         ret->ignore = FALSE;
 139         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Generating Response");
 140         ret->allowNotifications = TRUE;
 141
 142         flags = 0;
 143         send_len = wpabuf_len(data->out_buf) - data->out_used;
 144         if (1 + send_len > data->fragment_size) {
 145                 send_len = data->fragment_size - 1;
 146                 flags |= IKEV2_FLAGS_MORE_FRAGMENTS;
 147                 if (data->out_used == 0) {
 148                         flags |= IKEV2_FLAGS_LENGTH_INCLUDED;
 149                         send_len -= 4;
 150                 }
 151         }
 152 #ifdef CCNS_PL
 153         /* Some issues figuring out the length of the message if Message Length
 154          * field not included?! */
 155         if (!(flags & IKEV2_FLAGS_LENGTH_INCLUDED))
 156                 flags |= IKEV2_FLAGS_LENGTH_INCLUDED;
 157 #endif /* CCNS_PL */
 158
 159         plen = 1 + send_len;
 160         if (flags & IKEV2_FLAGS_LENGTH_INCLUDED)
 161                 plen += 4;
 162         if (data->keys_ready) {
 163                 const struct ikev2_integ_alg *integ;
 164                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Add Integrity Checksum "
 165                            "Data");
 166                 flags |= IKEV2_FLAGS_ICV_INCLUDED;
 167                 integ = ikev2_get_integ(data->ikev2.proposal.integ);
 168                 if (integ == NULL) {
 169                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Unknown INTEG "
 170                                    "transform / cannot generate ICV");
 171                         return NULL;
 172                 }
 173                 icv_len = integ->hash_len;
 174
 175                 plen += icv_len;
 176         }
 177         resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_IKEV2, plen,
 178                              EAP_CODE_RESPONSE, id);
 179         if (resp == NULL)
 180                 return NULL;
 181
 182         wpabuf_put_u8(resp, flags); /* Flags */
 183         if (flags & IKEV2_FLAGS_LENGTH_INCLUDED)
 184                 wpabuf_put_be32(resp, wpabuf_len(data->out_buf));
 185
 186         wpabuf_put_data(resp, wpabuf_head_u8(data->out_buf) + data->out_used,
 187                         send_len);
 188         data->out_used += send_len;
 189
 190         if (flags & IKEV2_FLAGS_ICV_INCLUDED) {
 191                 const u8 *msg = wpabuf_head(resp);
 192                 size_t len = wpabuf_len(resp);
 193                 ikev2_integ_hash(data->ikev2.proposal.integ,
 194                                  data->ikev2.keys.SK_ar,
 195                                  data->ikev2.keys.SK_integ_len,
 196                                  msg, len, wpabuf_put(resp, icv_len));
 197         }
 198
 199         ret->methodState = METHOD_MAY_CONT;
 200         ret->decision = DECISION_FAIL;
 201
 202         if (data->out_used == wpabuf_len(data->out_buf)) {
 203                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Sending out %lu bytes "
 204                            "(message sent completely)",
 205                            (unsigned long) send_len);
 206                 wpabuf_free(data->out_buf);
 207                 data->out_buf = NULL;
 208                 data->out_used = 0;
 209                 switch (data->ikev2.state) {
 210                 case SA_AUTH:
 211                         /* SA_INIT was sent out, so message have to be
 212                          * integrity protected from now on. */
 213                         data->keys_ready = 1;
 214                         break;
 215                 case IKEV2_DONE:
 216                         ret->methodState = METHOD_DONE;
 217                         if (data->state == FAIL)
 218                                 break;
 219                         ret->decision = DECISION_COND_SUCC;
 220                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Authentication "
 221                                    "completed successfully");
 222                         if (eap_ikev2_peer_keymat(data))
 223                                 break;
 224                         eap_ikev2_state(data, DONE);
 225                         break;
 226                 case IKEV2_FAILED:
 227                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Authentication "
 228                                    "failed");
 229                         ret->methodState = METHOD_DONE;
 230                         ret->decision = DECISION_FAIL;
 231                         break;
 232                 default:
 233                         break;
 234                 }
 235         } else {
 236                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Sending out %lu bytes "
 237                            "(%lu more to send)", (unsigned long) send_len,
 238                            (unsigned long) wpabuf_len(data->out_buf) -
 239                            data->out_used);
 240                 eap_ikev2_state(data, WAIT_FRAG_ACK);
 241         }
 242
 243         return resp;
 244 }
 245
 246
 247 static int eap_ikev2_process_icv(struct eap_ikev2_data *data,
 248                                  const struct wpabuf *reqData,
 249                                  u8 flags, const u8 *pos, const u8 **end)
 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) {
 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                 data->in_buf = wpabuf_alloc(message_length);
 305                 if (data->in_buf == NULL) {
 306                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: No memory for "
 307                                    "message");
 308                         ret->ignore = TRUE;
 309                         return NULL;
 310                 }
 311                 wpabuf_put_data(data->in_buf, buf, len);
 312                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Received %lu bytes in first "
 313                            "fragment, waiting for %lu bytes more",
 314                            (unsigned long) len,
 315                            (unsigned long) wpabuf_tailroom(data->in_buf));
 316         }
 317
 318         return eap_ikev2_build_frag_ack(id, EAP_CODE_RESPONSE);
 319 }
 320
 321
 322 static struct wpabuf * eap_ikev2_process(struct eap_sm *sm, void *priv,
 323                                          struct eap_method_ret *ret,
 324                                          const struct wpabuf *reqData)
 325 {
 326         struct eap_ikev2_data *data = priv;
 327         const u8 *start, *pos, *end;
 328         size_t len;
 329         u8 flags, id;
 330         u32 message_length = 0;
 331         struct wpabuf tmpbuf;
 332
 333         pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_IKEV2, reqData, &len);
 334         if (pos == NULL) {
 335                 ret->ignore = TRUE;
 336                 return NULL;
 337         }
 338
 339         id = eap_get_id(reqData);
 340
 341         start = pos;
 342         end = start + len;
 343
 344         if (len == 0)
 345                 flags = 0; /* fragment ack */
 346         else
 347                 flags = *pos++;
 348
 349         if (eap_ikev2_process_icv(data, reqData, flags, pos, &end) < 0) {
 350                 ret->ignore = TRUE;
 351                 return NULL;
 352         }
 353
 354         if (flags & IKEV2_FLAGS_LENGTH_INCLUDED) {
 355                 if (end - pos < 4) {
 356                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Message underflow");
 357                         ret->ignore = TRUE;
 358                         return NULL;
 359                 }
 360                 message_length = WPA_GET_BE32(pos);
 361                 pos += 4;
 362
 363                 if (message_length < (u32) (end - pos)) {
 364                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Invalid Message "
 365                                    "Length (%d; %ld remaining in this msg)",
 366                                    message_length, (long) (end - pos));
 367                         ret->ignore = TRUE;
 368                         return NULL;
 369                 }
 370         }
 371
 372         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Received packet: Flags 0x%x "
 373                    "Message Length %u", flags, message_length);
 374
 375         if (data->state == WAIT_FRAG_ACK) {
 376 #ifdef CCNS_PL
 377                 if (len > 1) /* Empty Flags field included in ACK */
 378 #else /* CCNS_PL */
 379                 if (len != 0)
 380 #endif /* CCNS_PL */
 381                 {
 382                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Unexpected payload "
 383                                    "in WAIT_FRAG_ACK state");
 384                         ret->ignore = TRUE;
 385                         return NULL;
 386                 }
 387                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Fragment acknowledged");
 388                 eap_ikev2_state(data, PROC_MSG);
 389                 return eap_ikev2_build_msg(data, ret, id);
 390         }
 391
 392         if (data->in_buf && eap_ikev2_process_cont(data, pos, end - pos) < 0) {
 393                 ret->ignore = TRUE;
 394                 return NULL;
 395         }
 396
 397         if (flags & IKEV2_FLAGS_MORE_FRAGMENTS) {
 398                 return eap_ikev2_process_fragment(data, ret, id, flags,
 399                                                   message_length, pos,
 400                                                   end - pos);
 401         }
 402
 403         if (data->in_buf == NULL) {
 404                 /* Wrap unfragmented messages as wpabuf without extra copy */
 405                 wpabuf_set(&tmpbuf, pos, end - pos);
 406                 data->in_buf = &tmpbuf;
 407         }
 408
 409         if (ikev2_responder_process(&data->ikev2, data->in_buf) < 0) {
 410                 if (data->in_buf == &tmpbuf)
 411                         data->in_buf = NULL;
 412                 eap_ikev2_state(data, FAIL);
 413                 return NULL;
 414         }
 415
 416         if (data->in_buf != &tmpbuf)
 417                 wpabuf_free(data->in_buf);
 418         data->in_buf = NULL;
 419
 420         if (data->out_buf == NULL) {
 421                 data->out_buf = ikev2_responder_build(&data->ikev2);
 422                 if (data->out_buf == NULL) {
 423                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Failed to generate "
 424                                    "IKEv2 message");
 425                         return NULL;
 426                 }
 427                 data->out_used = 0;
 428         }
 429
 430         eap_ikev2_state(data, PROC_MSG);
 431         return eap_ikev2_build_msg(data, ret, id);
 432 }
 433
 434
 435 static Boolean eap_ikev2_isKeyAvailable(struct eap_sm *sm, void *priv)
 436 {
 437         struct eap_ikev2_data *data = priv;
 438         return data->state == DONE && data->keymat_ok;
 439 }
 440
 441
 442 static u8 * eap_ikev2_getKey(struct eap_sm *sm, void *priv, size_t *len)
 443 {
 444         struct eap_ikev2_data *data = priv;
 445         u8 *key;
 446
 447         if (data->state != DONE || !data->keymat_ok)
 448                 return NULL;
 449
 450         key = os_malloc(EAP_MSK_LEN);
 451         if (key) {
 452                 os_memcpy(key, data->keymat, EAP_MSK_LEN);
 453                 *len = EAP_MSK_LEN;
 454         }
 455
 456         return key;
 457 }
 458
 459
 460 static u8 * eap_ikev2_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
 461 {
 462         struct eap_ikev2_data *data = priv;
 463         u8 *key;
 464
 465         if (data->state != DONE || !data->keymat_ok)
 466                 return NULL;
 467
 468         key = os_malloc(EAP_EMSK_LEN);
 469         if (key) {
 470                 os_memcpy(key, data->keymat + EAP_MSK_LEN, EAP_EMSK_LEN);
 471                 *len = EAP_EMSK_LEN;
 472         }
 473
 474         return key;
 475 }
 476
 477
 478 int eap_peer_ikev2_register(void)
 479 {
 480         struct eap_method *eap;
 481         int ret;
 482
 483         eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
 484                                     EAP_VENDOR_IETF, EAP_TYPE_IKEV2,
 485                                     "IKEV2");
 486         if (eap == NULL)
 487                 return -1;
 488
 489         eap->init = eap_ikev2_init;
 490         eap->deinit = eap_ikev2_deinit;
 491         eap->process = eap_ikev2_process;
 492         eap->isKeyAvailable = eap_ikev2_isKeyAvailable;
 493         eap->getKey = eap_ikev2_getKey;
 494         eap->get_emsk = eap_ikev2_get_emsk;
 495
 496         ret = eap_peer_method_register(eap);
 497         if (ret)
 498                 eap_peer_method_free(eap);
 499         return ret;
 500 }