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 = os_memdup(sm->server_id, sm->server_id_len);
 107         if (data->ikev2.IDi == NULL)
 108                 goto failed;
 109         data->ikev2.IDi_len = sm->server_id_len;
 110
 111         data->ikev2.get_shared_secret = eap_ikev2_get_shared_secret;
 112         data->ikev2.cb_ctx = sm;
 113
 114         return data;
 115
 116 failed:
 117         ikev2_initiator_deinit(&data->ikev2);
 118         os_free(data);
 119         return NULL;
 120 }
 121
 122
 123 static void eap_ikev2_reset(struct eap_sm *sm, void *priv)
 124 {
 125         struct eap_ikev2_data *data = priv;
 126         wpabuf_free(data->in_buf);
 127         wpabuf_free(data->out_buf);
 128         ikev2_initiator_deinit(&data->ikev2);
 129         bin_clear_free(data, sizeof(*data));
 130 }
 131
 132
 133 static struct wpabuf * eap_ikev2_build_msg(struct eap_ikev2_data *data, u8 id)
 134 {
 135         struct wpabuf *req;
 136         u8 flags;
 137         size_t send_len, plen, icv_len = 0;
 138
 139         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Generating Request");
 140
 141         flags = 0;
 142         send_len = wpabuf_len(data->out_buf) - data->out_used;
 143         if (1 + send_len > data->fragment_size) {
 144                 send_len = data->fragment_size - 1;
 145                 flags |= IKEV2_FLAGS_MORE_FRAGMENTS;
 146                 if (data->out_used == 0) {
 147                         flags |= IKEV2_FLAGS_LENGTH_INCLUDED;
 148                         send_len -= 4;
 149                 }
 150         }
 151
 152         plen = 1 + send_len;
 153         if (flags & IKEV2_FLAGS_LENGTH_INCLUDED)
 154                 plen += 4;
 155         if (data->keys_ready) {
 156                 const struct ikev2_integ_alg *integ;
 157                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Add Integrity Checksum "
 158                            "Data");
 159                 flags |= IKEV2_FLAGS_ICV_INCLUDED;
 160                 integ = ikev2_get_integ(data->ikev2.proposal.integ);
 161                 if (integ == NULL) {
 162                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Unknown INTEG "
 163                                    "transform / cannot generate ICV");
 164                         return NULL;
 165                 }
 166                 icv_len = integ->hash_len;
 167
 168                 plen += icv_len;
 169         }
 170         req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_IKEV2, plen,
 171                             EAP_CODE_REQUEST, id);
 172         if (req == NULL)
 173                 return NULL;
 174
 175         wpabuf_put_u8(req, flags); /* Flags */
 176         if (flags & IKEV2_FLAGS_LENGTH_INCLUDED)
 177                 wpabuf_put_be32(req, wpabuf_len(data->out_buf));
 178
 179         wpabuf_put_data(req, wpabuf_head_u8(data->out_buf) + data->out_used,
 180                         send_len);
 181         data->out_used += send_len;
 182
 183         if (flags & IKEV2_FLAGS_ICV_INCLUDED) {
 184                 const u8 *msg = wpabuf_head(req);
 185                 size_t len = wpabuf_len(req);
 186                 ikev2_integ_hash(data->ikev2.proposal.integ,
 187                                  data->ikev2.keys.SK_ai,
 188                                  data->ikev2.keys.SK_integ_len,
 189                                  msg, len, wpabuf_put(req, icv_len));
 190         }
 191
 192         if (data->out_used == wpabuf_len(data->out_buf)) {
 193                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Sending out %lu bytes "
 194                            "(message sent completely)",
 195                            (unsigned long) send_len);
 196                 wpabuf_free(data->out_buf);
 197                 data->out_buf = NULL;
 198                 data->out_used = 0;
 199         } else {
 200                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Sending out %lu bytes "
 201                            "(%lu more to send)", (unsigned long) send_len,
 202                            (unsigned long) wpabuf_len(data->out_buf) -
 203                            data->out_used);
 204                 eap_ikev2_state(data, WAIT_FRAG_ACK);
 205         }
 206
 207         return req;
 208 }
 209
 210
 211 static struct wpabuf * eap_ikev2_buildReq(struct eap_sm *sm, void *priv, u8 id)
 212 {
 213         struct eap_ikev2_data *data = priv;
 214
 215         switch (data->state) {
 216         case MSG:
 217                 if (data->out_buf == NULL) {
 218                         data->out_buf = ikev2_initiator_build(&data->ikev2);
 219                         if (data->out_buf == NULL) {
 220                                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Failed to "
 221                                            "generate IKEv2 message");
 222                                 return NULL;
 223                         }
 224                         data->out_used = 0;
 225                 }
 226                 /* fall through */
 227         case WAIT_FRAG_ACK:
 228                 return eap_ikev2_build_msg(data, id);
 229         case FRAG_ACK:
 230                 return eap_ikev2_build_frag_ack(id, EAP_CODE_REQUEST);
 231         default:
 232                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Unexpected state %d in "
 233                            "buildReq", data->state);
 234                 return NULL;
 235         }
 236 }
 237
 238
 239 static Boolean eap_ikev2_check(struct eap_sm *sm, void *priv,
 240                                struct wpabuf *respData)
 241 {
 242         const u8 *pos;
 243         size_t len;
 244
 245         pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_IKEV2, respData,
 246                                &len);
 247         if (pos == NULL) {
 248                 wpa_printf(MSG_INFO, "EAP-IKEV2: Invalid frame");
 249                 return TRUE;
 250         }
 251
 252         return FALSE;
 253 }
 254
 255
 256 static int eap_ikev2_process_icv(struct eap_ikev2_data *data,
 257                                  const struct wpabuf *respData,
 258                                  u8 flags, const u8 *pos, const u8 **end,
 259                                  int frag_ack)
 260 {
 261         if (flags & IKEV2_FLAGS_ICV_INCLUDED) {
 262                 int icv_len = eap_ikev2_validate_icv(
 263                         data->ikev2.proposal.integ, &data->ikev2.keys, 0,
 264                         respData, pos, *end);
 265                 if (icv_len < 0)
 266                         return -1;
 267                 /* Hide Integrity Checksum Data from further processing */
 268                 *end -= icv_len;
 269         } else if (data->keys_ready && !frag_ack) {
 270                 wpa_printf(MSG_INFO, "EAP-IKEV2: The message should have "
 271                            "included integrity checksum");
 272                 return -1;
 273         }
 274
 275         return 0;
 276 }
 277
 278
 279 static int eap_ikev2_process_cont(struct eap_ikev2_data *data,
 280                                   const u8 *buf, size_t len)
 281 {
 282         /* Process continuation of a pending message */
 283         if (len > wpabuf_tailroom(data->in_buf)) {
 284                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Fragment overflow");
 285                 eap_ikev2_state(data, FAIL);
 286                 return -1;
 287         }
 288
 289         wpabuf_put_data(data->in_buf, buf, len);
 290         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Received %lu bytes, waiting for %lu "
 291                    "bytes more", (unsigned long) len,
 292                    (unsigned long) wpabuf_tailroom(data->in_buf));
 293
 294         return 0;
 295 }
 296
 297
 298 static int eap_ikev2_process_fragment(struct eap_ikev2_data *data,
 299                                       u8 flags, u32 message_length,
 300                                       const u8 *buf, size_t len)
 301 {
 302         /* Process a fragment that is not the last one of the message */
 303         if (data->in_buf == NULL && !(flags & IKEV2_FLAGS_LENGTH_INCLUDED)) {
 304                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: No Message Length field in "
 305                            "a fragmented packet");
 306                 return -1;
 307         }
 308
 309         if (data->in_buf == NULL) {
 310                 /* First fragment of the message */
 311                 if (message_length > 50000) {
 312                         /* Limit maximum memory allocation */
 313                         wpa_printf(MSG_DEBUG,
 314                                    "EAP-IKEV2: Ignore too long message");
 315                         return -1;
 316                 }
 317                 data->in_buf = wpabuf_alloc(message_length);
 318                 if (data->in_buf == NULL) {
 319                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: No memory for "
 320                                    "message");
 321                         return -1;
 322                 }
 323                 wpabuf_put_data(data->in_buf, buf, len);
 324                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Received %lu bytes in first "
 325                            "fragment, waiting for %lu bytes more",
 326                            (unsigned long) len,
 327                            (unsigned long) wpabuf_tailroom(data->in_buf));
 328         }
 329
 330         return 0;
 331 }
 332
 333
 334 static int eap_ikev2_server_keymat(struct eap_ikev2_data *data)
 335 {
 336         if (eap_ikev2_derive_keymat(
 337                     data->ikev2.proposal.prf, &data->ikev2.keys,
 338                     data->ikev2.i_nonce, data->ikev2.i_nonce_len,
 339                     data->ikev2.r_nonce, data->ikev2.r_nonce_len,
 340                     data->keymat) < 0) {
 341                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Failed to derive "
 342                            "key material");
 343                 return -1;
 344         }
 345         data->keymat_ok = 1;
 346         return 0;
 347 }
 348
 349
 350 static void eap_ikev2_process(struct eap_sm *sm, void *priv,
 351                               struct wpabuf *respData)
 352 {
 353         struct eap_ikev2_data *data = priv;
 354         const u8 *start, *pos, *end;
 355         size_t len;
 356         u8 flags;
 357         u32 message_length = 0;
 358         struct wpabuf tmpbuf;
 359
 360         pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_IKEV2, respData,
 361                                &len);
 362         if (pos == NULL)
 363                 return; /* Should not happen; message already verified */
 364
 365         start = pos;
 366         end = start + len;
 367
 368         if (len == 0) {
 369                 /* fragment ack */
 370                 flags = 0;
 371         } else
 372                 flags = *pos++;
 373
 374         if (eap_ikev2_process_icv(data, respData, flags, pos, &end,
 375                                   data->state == WAIT_FRAG_ACK && len == 0) < 0)
 376         {
 377                 eap_ikev2_state(data, FAIL);
 378                 return;
 379         }
 380
 381         if (flags & IKEV2_FLAGS_LENGTH_INCLUDED) {
 382                 if (end - pos < 4) {
 383                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Message underflow");
 384                         eap_ikev2_state(data, FAIL);
 385                         return;
 386                 }
 387                 message_length = WPA_GET_BE32(pos);
 388                 pos += 4;
 389
 390                 if (message_length < (u32) (end - pos)) {
 391                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Invalid Message "
 392                                    "Length (%d; %ld remaining in this msg)",
 393                                    message_length, (long) (end - pos));
 394                         eap_ikev2_state(data, FAIL);
 395                         return;
 396                 }
 397         }
 398         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Received packet: Flags 0x%x "
 399                    "Message Length %u", flags, message_length);
 400
 401         if (data->state == WAIT_FRAG_ACK) {
 402                 if (len != 0) {
 403                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Unexpected payload "
 404                                    "in WAIT_FRAG_ACK state");
 405                         eap_ikev2_state(data, FAIL);
 406                         return;
 407                 }
 408                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Fragment acknowledged");
 409                 eap_ikev2_state(data, MSG);
 410                 return;
 411         }
 412
 413         if (data->in_buf && eap_ikev2_process_cont(data, pos, end - pos) < 0) {
 414                 eap_ikev2_state(data, FAIL);
 415                 return;
 416         }
 417
 418         if (flags & IKEV2_FLAGS_MORE_FRAGMENTS) {
 419                 if (eap_ikev2_process_fragment(data, flags, message_length,
 420                                                pos, end - pos) < 0)
 421                         eap_ikev2_state(data, FAIL);
 422                 else
 423                         eap_ikev2_state(data, FRAG_ACK);
 424                 return;
 425         } else if (data->state == FRAG_ACK) {
 426                 wpa_printf(MSG_DEBUG, "EAP-TNC: All fragments received");
 427                 data->state = MSG;
 428         }
 429
 430         if (data->in_buf == NULL) {
 431                 /* Wrap unfragmented messages as wpabuf without extra copy */
 432                 wpabuf_set(&tmpbuf, pos, end - pos);
 433                 data->in_buf = &tmpbuf;
 434         }
 435
 436         if (ikev2_initiator_process(&data->ikev2, data->in_buf) < 0) {
 437                 if (data->in_buf == &tmpbuf)
 438                         data->in_buf = NULL;
 439                 eap_ikev2_state(data, FAIL);
 440                 return;
 441         }
 442
 443         switch (data->ikev2.state) {
 444         case SA_AUTH:
 445                 /* SA_INIT was sent out, so message have to be
 446                  * integrity protected from now on. */
 447                 data->keys_ready = 1;
 448                 break;
 449         case IKEV2_DONE:
 450                 if (data->state == FAIL)
 451                         break;
 452                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Authentication completed "
 453                            "successfully");
 454                 if (eap_ikev2_server_keymat(data))
 455                         break;
 456                 eap_ikev2_state(data, DONE);
 457                 break;
 458         default:
 459                 break;
 460         }
 461
 462         if (data->in_buf != &tmpbuf)
 463                 wpabuf_free(data->in_buf);
 464         data->in_buf = NULL;
 465 }
 466
 467
 468 static Boolean eap_ikev2_isDone(struct eap_sm *sm, void *priv)
 469 {
 470         struct eap_ikev2_data *data = priv;
 471         return data->state == DONE || data->state == FAIL;
 472 }
 473
 474
 475 static Boolean eap_ikev2_isSuccess(struct eap_sm *sm, void *priv)
 476 {
 477         struct eap_ikev2_data *data = priv;
 478         return data->state == DONE && data->ikev2.state == IKEV2_DONE &&
 479                 data->keymat_ok;
 480 }
 481
 482
 483 static u8 * eap_ikev2_getKey(struct eap_sm *sm, void *priv, size_t *len)
 484 {
 485         struct eap_ikev2_data *data = priv;
 486         u8 *key;
 487
 488         if (data->state != DONE || !data->keymat_ok)
 489                 return NULL;
 490
 491         key = os_malloc(EAP_MSK_LEN);
 492         if (key) {
 493                 os_memcpy(key, data->keymat, EAP_MSK_LEN);
 494                 *len = EAP_MSK_LEN;
 495         }
 496
 497         return key;
 498 }
 499
 500
 501 static u8 * eap_ikev2_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
 502 {
 503         struct eap_ikev2_data *data = priv;
 504         u8 *key;
 505
 506         if (data->state != DONE || !data->keymat_ok)
 507                 return NULL;
 508
 509         key = os_malloc(EAP_EMSK_LEN);
 510         if (key) {
 511                 os_memcpy(key, data->keymat + EAP_MSK_LEN, EAP_EMSK_LEN);
 512                 *len = EAP_EMSK_LEN;
 513         }
 514
 515         return key;
 516 }
 517
 518
 519 static u8 * eap_ikev2_get_session_id(struct eap_sm *sm, void *priv, size_t *len)
 520 {
 521         struct eap_ikev2_data *data = priv;
 522         u8 *sid;
 523         size_t sid_len;
 524         size_t offset;
 525
 526         if (data->state != DONE || !data->keymat_ok)
 527                 return NULL;
 528
 529         sid_len = 1 + data->ikev2.i_nonce_len + data->ikev2.r_nonce_len;
 530         sid = os_malloc(sid_len);
 531         if (sid) {
 532                 offset = 0;
 533                 sid[offset] = EAP_TYPE_IKEV2;
 534                 offset++;
 535                 os_memcpy(sid + offset, data->ikev2.i_nonce,
 536                           data->ikev2.i_nonce_len);
 537                 offset += data->ikev2.i_nonce_len;
 538                 os_memcpy(sid + offset, data->ikev2.r_nonce,
 539                           data->ikev2.r_nonce_len);
 540                 *len = sid_len;
 541                 wpa_hexdump(MSG_DEBUG, "EAP-IKEV2: Derived Session-Id",
 542                             sid, sid_len);
 543         }
 544
 545         return sid;
 546 }
 547
 548
 549 int eap_server_ikev2_register(void)
 550 {
 551         struct eap_method *eap;
 552
 553         eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
 554                                       EAP_VENDOR_IETF, EAP_TYPE_IKEV2,
 555                                       "IKEV2");
 556         if (eap == NULL)
 557                 return -1;
 558
 559         eap->init = eap_ikev2_init;
 560         eap->reset = eap_ikev2_reset;
 561         eap->buildReq = eap_ikev2_buildReq;
 562         eap->check = eap_ikev2_check;
 563         eap->process = eap_ikev2_process;
 564         eap->isDone = eap_ikev2_isDone;
 565         eap->getKey = eap_ikev2_getKey;
 566         eap->isSuccess = eap_ikev2_isSuccess;
 567         eap->get_emsk = eap_ikev2_get_emsk;
 568         eap->getSessionId = eap_ikev2_get_session_id;
 569
 570         return eap_server_method_register(eap);
 571 }