contrib/wpa/src/eap_server/eap_server_ikev2.c

   1 /*
   2  * EAP-IKEv2 server (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_initiator_data ikev2;
  19         enum { MSG, FRAG_ACK, 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 u8 * eap_ikev2_get_shared_secret(void *ctx, const u8 *IDr,
  31                                               size_t IDr_len,
  32                                               size_t *secret_len)
  33 {
  34         struct eap_sm *sm = ctx;
  35
  36         if (IDr == NULL) {
  37                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: No IDr received - default "
  38                            "to user identity from EAP-Identity");
  39                 IDr = sm->identity;
  40                 IDr_len = sm->identity_len;
  41         }
  42
  43         if (eap_user_get(sm, IDr, IDr_len, 0) < 0 || sm->user == NULL ||
  44             sm->user->password == NULL) {
  45                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: No user entry found");
  46                 return NULL;
  47         }
  48
  49         *secret_len = sm->user->password_len;
  50         return sm->user->password;
  51 }
  52
  53
  54 static const char * eap_ikev2_state_txt(int state)
  55 {
  56         switch (state) {
  57         case MSG:
  58                 return "MSG";
  59         case FRAG_ACK:
  60                 return "FRAG_ACK";
  61         case WAIT_FRAG_ACK:
  62                 return "WAIT_FRAG_ACK";
  63         case DONE:
  64                 return "DONE";
  65         case FAIL:
  66                 return "FAIL";
  67         default:
  68                 return "?";
  69         }
  70 }
  71
  72
  73 static void eap_ikev2_state(struct eap_ikev2_data *data, int state)
  74 {
  75         wpa_printf(MSG_DEBUG, "EAP-IKEV2: %s -> %s",
  76                    eap_ikev2_state_txt(data->state),
  77                    eap_ikev2_state_txt(state));
  78         data->state = state;
  79 }
  80
  81
  82 static void * eap_ikev2_init(struct eap_sm *sm)
  83 {
  84         struct eap_ikev2_data *data;
  85
  86         data = os_zalloc(sizeof(*data));
  87         if (data == NULL)
  88                 return NULL;
  89         data->state = MSG;
  90         data->fragment_size = sm->fragment_size > 0 ? sm->fragment_size :
  91                 IKEV2_FRAGMENT_SIZE;
  92         data->ikev2.state = SA_INIT;
  93         data->ikev2.peer_auth = PEER_AUTH_SECRET;
  94         data->ikev2.key_pad = (u8 *) os_strdup("Key Pad for EAP-IKEv2");
  95         if (data->ikev2.key_pad == NULL)
  96                 goto failed;
  97         data->ikev2.key_pad_len = 21;
  98
  99         /* TODO: make proposals configurable */
 100         data->ikev2.proposal.proposal_num = 1;
 101         data->ikev2.proposal.integ = AUTH_HMAC_SHA1_96;
 102         data->ikev2.proposal.prf = PRF_HMAC_SHA1;
 103         data->ikev2.proposal.encr = ENCR_AES_CBC;
 104         data->ikev2.proposal.dh = DH_GROUP2_1024BIT_MODP;
 105
 106         data->ikev2.IDi = (u8 *) os_strdup("hostapd");
 107         data->ikev2.IDi_len = 7;
 108
 109         data->ikev2.get_shared_secret = eap_ikev2_get_shared_secret;
 110         data->ikev2.cb_ctx = sm;
 111
 112         return data;
 113
 114 failed:
 115         ikev2_initiator_deinit(&data->ikev2);
 116         os_free(data);
 117         return NULL;
 118 }
 119
 120
 121 static void eap_ikev2_reset(struct eap_sm *sm, void *priv)
 122 {
 123         struct eap_ikev2_data *data = priv;
 124         wpabuf_free(data->in_buf);
 125         wpabuf_free(data->out_buf);
 126         ikev2_initiator_deinit(&data->ikev2);
 127         os_free(data);
 128 }
 129
 130
 131 static struct wpabuf * eap_ikev2_build_msg(struct eap_ikev2_data *data, u8 id)
 132 {
 133         struct wpabuf *req;
 134         u8 flags;
 135         size_t send_len, plen, icv_len = 0;
 136
 137         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Generating Request");
 138
 139         flags = 0;
 140         send_len = wpabuf_len(data->out_buf) - data->out_used;
 141         if (1 + send_len > data->fragment_size) {
 142                 send_len = data->fragment_size - 1;
 143                 flags |= IKEV2_FLAGS_MORE_FRAGMENTS;
 144                 if (data->out_used == 0) {
 145                         flags |= IKEV2_FLAGS_LENGTH_INCLUDED;
 146                         send_len -= 4;
 147                 }
 148         }
 149
 150         plen = 1 + send_len;
 151         if (flags & IKEV2_FLAGS_LENGTH_INCLUDED)
 152                 plen += 4;
 153         if (data->keys_ready) {
 154                 const struct ikev2_integ_alg *integ;
 155                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Add Integrity Checksum "
 156                            "Data");
 157                 flags |= IKEV2_FLAGS_ICV_INCLUDED;
 158                 integ = ikev2_get_integ(data->ikev2.proposal.integ);
 159                 if (integ == NULL) {
 160                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Unknown INTEG "
 161                                    "transform / cannot generate ICV");
 162                         return NULL;
 163                 }
 164                 icv_len = integ->hash_len;
 165
 166                 plen += icv_len;
 167         }
 168         req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_IKEV2, plen,
 169                             EAP_CODE_REQUEST, id);
 170         if (req == NULL)
 171                 return NULL;
 172
 173         wpabuf_put_u8(req, flags); /* Flags */
 174         if (flags & IKEV2_FLAGS_LENGTH_INCLUDED)
 175                 wpabuf_put_be32(req, wpabuf_len(data->out_buf));
 176
 177         wpabuf_put_data(req, wpabuf_head_u8(data->out_buf) + data->out_used,
 178                         send_len);
 179         data->out_used += send_len;
 180
 181         if (flags & IKEV2_FLAGS_ICV_INCLUDED) {
 182                 const u8 *msg = wpabuf_head(req);
 183                 size_t len = wpabuf_len(req);
 184                 ikev2_integ_hash(data->ikev2.proposal.integ,
 185                                  data->ikev2.keys.SK_ai,
 186                                  data->ikev2.keys.SK_integ_len,
 187                                  msg, len, wpabuf_put(req, icv_len));
 188         }
 189
 190         if (data->out_used == wpabuf_len(data->out_buf)) {
 191                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Sending out %lu bytes "
 192                            "(message sent completely)",
 193                            (unsigned long) send_len);
 194                 wpabuf_free(data->out_buf);
 195                 data->out_buf = NULL;
 196                 data->out_used = 0;
 197         } else {
 198                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Sending out %lu bytes "
 199                            "(%lu more to send)", (unsigned long) send_len,
 200                            (unsigned long) wpabuf_len(data->out_buf) -
 201                            data->out_used);
 202                 eap_ikev2_state(data, WAIT_FRAG_ACK);
 203         }
 204
 205         return req;
 206 }
 207
 208
 209 static struct wpabuf * eap_ikev2_buildReq(struct eap_sm *sm, void *priv, u8 id)
 210 {
 211         struct eap_ikev2_data *data = priv;
 212
 213         switch (data->state) {
 214         case MSG:
 215                 if (data->out_buf == NULL) {
 216                         data->out_buf = ikev2_initiator_build(&data->ikev2);
 217                         if (data->out_buf == NULL) {
 218                                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Failed to "
 219                                            "generate IKEv2 message");
 220                                 return NULL;
 221                         }
 222                         data->out_used = 0;
 223                 }
 224                 /* pass through */
 225         case WAIT_FRAG_ACK:
 226                 return eap_ikev2_build_msg(data, id);
 227         case FRAG_ACK:
 228                 return eap_ikev2_build_frag_ack(id, EAP_CODE_REQUEST);
 229         default:
 230                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Unexpected state %d in "
 231                            "buildReq", data->state);
 232                 return NULL;
 233         }
 234 }
 235
 236
 237 static Boolean eap_ikev2_check(struct eap_sm *sm, void *priv,
 238                                struct wpabuf *respData)
 239 {
 240         const u8 *pos;
 241         size_t len;
 242
 243         pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_IKEV2, respData,
 244                                &len);
 245         if (pos == NULL) {
 246                 wpa_printf(MSG_INFO, "EAP-IKEV2: Invalid frame");
 247                 return TRUE;
 248         }
 249
 250         return FALSE;
 251 }
 252
 253
 254 static int eap_ikev2_process_icv(struct eap_ikev2_data *data,
 255                                  const struct wpabuf *respData,
 256                                  u8 flags, const u8 *pos, const u8 **end)
 257 {
 258         if (flags & IKEV2_FLAGS_ICV_INCLUDED) {
 259                 int icv_len = eap_ikev2_validate_icv(
 260                         data->ikev2.proposal.integ, &data->ikev2.keys, 0,
 261                         respData, pos, *end);
 262                 if (icv_len < 0)
 263                         return -1;
 264                 /* Hide Integrity Checksum Data from further processing */
 265                 *end -= icv_len;
 266         } else if (data->keys_ready) {
 267                 wpa_printf(MSG_INFO, "EAP-IKEV2: The message should have "
 268                            "included integrity checksum");
 269                 return -1;
 270         }
 271
 272         return 0;
 273 }
 274
 275
 276 static int eap_ikev2_process_cont(struct eap_ikev2_data *data,
 277                                   const u8 *buf, size_t len)
 278 {
 279         /* Process continuation of a pending message */
 280         if (len > wpabuf_tailroom(data->in_buf)) {
 281                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Fragment overflow");
 282                 eap_ikev2_state(data, FAIL);
 283                 return -1;
 284         }
 285
 286         wpabuf_put_data(data->in_buf, buf, len);
 287         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Received %lu bytes, waiting for %lu "
 288                    "bytes more", (unsigned long) len,
 289                    (unsigned long) wpabuf_tailroom(data->in_buf));
 290
 291         return 0;
 292 }
 293
 294
 295 static int eap_ikev2_process_fragment(struct eap_ikev2_data *data,
 296                                       u8 flags, u32 message_length,
 297                                       const u8 *buf, size_t len)
 298 {
 299         /* Process a fragment that is not the last one of the message */
 300         if (data->in_buf == NULL && !(flags & IKEV2_FLAGS_LENGTH_INCLUDED)) {
 301                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: No Message Length field in "
 302                            "a fragmented packet");
 303                 return -1;
 304         }
 305
 306         if (data->in_buf == NULL) {
 307                 /* First fragment of the message */
 308                 data->in_buf = wpabuf_alloc(message_length);
 309                 if (data->in_buf == NULL) {
 310                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: No memory for "
 311                                    "message");
 312                         return -1;
 313                 }
 314                 wpabuf_put_data(data->in_buf, buf, len);
 315                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Received %lu bytes in first "
 316                            "fragment, waiting for %lu bytes more",
 317                            (unsigned long) len,
 318                            (unsigned long) wpabuf_tailroom(data->in_buf));
 319         }
 320
 321         return 0;
 322 }
 323
 324
 325 static int eap_ikev2_server_keymat(struct eap_ikev2_data *data)
 326 {
 327         if (eap_ikev2_derive_keymat(
 328                     data->ikev2.proposal.prf, &data->ikev2.keys,
 329                     data->ikev2.i_nonce, data->ikev2.i_nonce_len,
 330                     data->ikev2.r_nonce, data->ikev2.r_nonce_len,
 331                     data->keymat) < 0) {
 332                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Failed to derive "
 333                            "key material");
 334                 return -1;
 335         }
 336         data->keymat_ok = 1;
 337         return 0;
 338 }
 339
 340
 341 static void eap_ikev2_process(struct eap_sm *sm, void *priv,
 342                               struct wpabuf *respData)
 343 {
 344         struct eap_ikev2_data *data = priv;
 345         const u8 *start, *pos, *end;
 346         size_t len;
 347         u8 flags;
 348         u32 message_length = 0;
 349         struct wpabuf tmpbuf;
 350
 351         pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_IKEV2, respData,
 352                                &len);
 353         if (pos == NULL)
 354                 return; /* Should not happen; message already verified */
 355
 356         start = pos;
 357         end = start + len;
 358
 359         if (len == 0) {
 360                 /* fragment ack */
 361                 flags = 0;
 362         } else
 363                 flags = *pos++;
 364
 365         if (eap_ikev2_process_icv(data, respData, flags, pos, &end) < 0) {
 366                 eap_ikev2_state(data, FAIL);
 367                 return;
 368         }
 369
 370         if (flags & IKEV2_FLAGS_LENGTH_INCLUDED) {
 371                 if (end - pos < 4) {
 372                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Message underflow");
 373                         eap_ikev2_state(data, FAIL);
 374                         return;
 375                 }
 376                 message_length = WPA_GET_BE32(pos);
 377                 pos += 4;
 378
 379                 if (message_length < (u32) (end - pos)) {
 380                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Invalid Message "
 381                                    "Length (%d; %ld remaining in this msg)",
 382                                    message_length, (long) (end - pos));
 383                         eap_ikev2_state(data, FAIL);
 384                         return;
 385                 }
 386         }
 387         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Received packet: Flags 0x%x "
 388                    "Message Length %u", flags, message_length);
 389
 390         if (data->state == WAIT_FRAG_ACK) {
 391                 if (len != 0) {
 392                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Unexpected payload "
 393                                    "in WAIT_FRAG_ACK state");
 394                         eap_ikev2_state(data, FAIL);
 395                         return;
 396                 }
 397                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Fragment acknowledged");
 398                 eap_ikev2_state(data, MSG);
 399                 return;
 400         }
 401
 402         if (data->in_buf && eap_ikev2_process_cont(data, pos, end - pos) < 0) {
 403                 eap_ikev2_state(data, FAIL);
 404                 return;
 405         }
 406
 407         if (flags & IKEV2_FLAGS_MORE_FRAGMENTS) {
 408                 if (eap_ikev2_process_fragment(data, flags, message_length,
 409                                                pos, end - pos) < 0)
 410                         eap_ikev2_state(data, FAIL);
 411                 else
 412                         eap_ikev2_state(data, FRAG_ACK);
 413                 return;
 414         } else if (data->state == FRAG_ACK) {
 415                 wpa_printf(MSG_DEBUG, "EAP-TNC: All fragments received");
 416                 data->state = MSG;
 417         }
 418
 419         if (data->in_buf == NULL) {
 420                 /* Wrap unfragmented messages as wpabuf without extra copy */
 421                 wpabuf_set(&tmpbuf, pos, end - pos);
 422                 data->in_buf = &tmpbuf;
 423         }
 424
 425         if (ikev2_initiator_process(&data->ikev2, data->in_buf) < 0) {
 426                 if (data->in_buf == &tmpbuf)
 427                         data->in_buf = NULL;
 428                 eap_ikev2_state(data, FAIL);
 429                 return;
 430         }
 431
 432         switch (data->ikev2.state) {
 433         case SA_AUTH:
 434                 /* SA_INIT was sent out, so message have to be
 435                  * integrity protected from now on. */
 436                 data->keys_ready = 1;
 437                 break;
 438         case IKEV2_DONE:
 439                 if (data->state == FAIL)
 440                         break;
 441                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Authentication completed "
 442                            "successfully");
 443                 if (eap_ikev2_server_keymat(data))
 444                         break;
 445                 eap_ikev2_state(data, DONE);
 446                 break;
 447         default:
 448                 break;
 449         }
 450
 451         if (data->in_buf != &tmpbuf)
 452                 wpabuf_free(data->in_buf);
 453         data->in_buf = NULL;
 454 }
 455
 456
 457 static Boolean eap_ikev2_isDone(struct eap_sm *sm, void *priv)
 458 {
 459         struct eap_ikev2_data *data = priv;
 460         return data->state == DONE || data->state == FAIL;
 461 }
 462
 463
 464 static Boolean eap_ikev2_isSuccess(struct eap_sm *sm, void *priv)
 465 {
 466         struct eap_ikev2_data *data = priv;
 467         return data->state == DONE && data->ikev2.state == IKEV2_DONE &&
 468                 data->keymat_ok;
 469 }
 470
 471
 472 static u8 * eap_ikev2_getKey(struct eap_sm *sm, void *priv, size_t *len)
 473 {
 474         struct eap_ikev2_data *data = priv;
 475         u8 *key;
 476
 477         if (data->state != DONE || !data->keymat_ok)
 478                 return NULL;
 479
 480         key = os_malloc(EAP_MSK_LEN);
 481         if (key) {
 482                 os_memcpy(key, data->keymat, EAP_MSK_LEN);
 483                 *len = EAP_MSK_LEN;
 484         }
 485
 486         return key;
 487 }
 488
 489
 490 static u8 * eap_ikev2_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
 491 {
 492         struct eap_ikev2_data *data = priv;
 493         u8 *key;
 494
 495         if (data->state != DONE || !data->keymat_ok)
 496                 return NULL;
 497
 498         key = os_malloc(EAP_EMSK_LEN);
 499         if (key) {
 500                 os_memcpy(key, data->keymat + EAP_MSK_LEN, EAP_EMSK_LEN);
 501                 *len = EAP_EMSK_LEN;
 502         }
 503
 504         return key;
 505 }
 506
 507
 508 int eap_server_ikev2_register(void)
 509 {
 510         struct eap_method *eap;
 511         int ret;
 512
 513         eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
 514                                       EAP_VENDOR_IETF, EAP_TYPE_IKEV2,
 515                                       "IKEV2");
 516         if (eap == NULL)
 517                 return -1;
 518
 519         eap->init = eap_ikev2_init;
 520         eap->reset = eap_ikev2_reset;
 521         eap->buildReq = eap_ikev2_buildReq;
 522         eap->check = eap_ikev2_check;
 523         eap->process = eap_ikev2_process;
 524         eap->isDone = eap_ikev2_isDone;
 525         eap->getKey = eap_ikev2_getKey;
 526         eap->isSuccess = eap_ikev2_isSuccess;
 527         eap->get_emsk = eap_ikev2_get_emsk;
 528
 529         ret = eap_server_method_register(eap);
 530         if (ret)
 531                 eap_server_method_free(eap);
 532         return ret;
 533 }