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 program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  * Alternatively, this software may be distributed under the terms of BSD
  10  * license.
  11  *
  12  * See README and COPYING for more details.
  13  */
  14
  15 #include "includes.h"
  16
  17 #include "common.h"
  18 #include "eap_i.h"
  19 #include "eap_common/eap_ikev2_common.h"
  20 #include "ikev2.h"
  21
  22
  23 struct eap_ikev2_data {
  24         struct ikev2_responder_data ikev2;
  25         enum { WAIT_START, PROC_MSG, WAIT_FRAG_ACK, DONE, FAIL } state;
  26         struct wpabuf *in_buf;
  27         struct wpabuf *out_buf;
  28         size_t out_used;
  29         size_t fragment_size;
  30         int keys_ready;
  31         u8 keymat[EAP_MSK_LEN + EAP_EMSK_LEN];
  32         int keymat_ok;
  33 };
  34
  35
  36 static const char * eap_ikev2_state_txt(int state)
  37 {
  38         switch (state) {
  39         case WAIT_START:
  40                 return "WAIT_START";
  41         case PROC_MSG:
  42                 return "PROC_MSG";
  43         case WAIT_FRAG_ACK:
  44                 return "WAIT_FRAG_ACK";
  45         case DONE:
  46                 return "DONE";
  47         case FAIL:
  48                 return "FAIL";
  49         default:
  50                 return "?";
  51         }
  52 }
  53
  54
  55 static void eap_ikev2_state(struct eap_ikev2_data *data, int state)
  56 {
  57         wpa_printf(MSG_DEBUG, "EAP-IKEV2: %s -> %s",
  58                    eap_ikev2_state_txt(data->state),
  59                    eap_ikev2_state_txt(state));
  60         data->state = state;
  61 }
  62
  63
  64 static void * eap_ikev2_init(struct eap_sm *sm)
  65 {
  66         struct eap_ikev2_data *data;
  67         const u8 *identity, *password;
  68         size_t identity_len, password_len;
  69
  70         identity = eap_get_config_identity(sm, &identity_len);
  71         if (identity == NULL) {
  72                 wpa_printf(MSG_INFO, "EAP-IKEV2: No identity available");
  73                 return NULL;
  74         }
  75
  76         data = os_zalloc(sizeof(*data));
  77         if (data == NULL)
  78                 return NULL;
  79         data->state = WAIT_START;
  80         data->fragment_size = IKEV2_FRAGMENT_SIZE;
  81         data->ikev2.state = SA_INIT;
  82         data->ikev2.peer_auth = PEER_AUTH_SECRET;
  83         data->ikev2.key_pad = (u8 *) os_strdup("Key Pad for EAP-IKEv2");
  84         if (data->ikev2.key_pad == NULL)
  85                 goto failed;
  86         data->ikev2.key_pad_len = 21;
  87         data->ikev2.IDr = os_malloc(identity_len);
  88         if (data->ikev2.IDr == NULL)
  89                 goto failed;
  90         os_memcpy(data->ikev2.IDr, identity, identity_len);
  91         data->ikev2.IDr_len = identity_len;
  92
  93         password = eap_get_config_password(sm, &password_len);
  94         if (password) {
  95                 data->ikev2.shared_secret = os_malloc(password_len);
  96                 if (data->ikev2.shared_secret == NULL)
  97                         goto failed;
  98                 os_memcpy(data->ikev2.shared_secret, password, password_len);
  99                 data->ikev2.shared_secret_len = password_len;
 100         }
 101
 102         return data;
 103
 104 failed:
 105         ikev2_responder_deinit(&data->ikev2);
 106         os_free(data);
 107         return NULL;
 108 }
 109
 110
 111 static void eap_ikev2_deinit(struct eap_sm *sm, void *priv)
 112 {
 113         struct eap_ikev2_data *data = priv;
 114         wpabuf_free(data->in_buf);
 115         wpabuf_free(data->out_buf);
 116         ikev2_responder_deinit(&data->ikev2);
 117         os_free(data);
 118 }
 119
 120
 121 static int eap_ikev2_peer_keymat(struct eap_ikev2_data *data)
 122 {
 123         if (eap_ikev2_derive_keymat(
 124                     data->ikev2.proposal.prf, &data->ikev2.keys,
 125                     data->ikev2.i_nonce, data->ikev2.i_nonce_len,
 126                     data->ikev2.r_nonce, data->ikev2.r_nonce_len,
 127                     data->keymat) < 0) {
 128                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Failed to "
 129                            "derive key material");
 130                 return -1;
 131         }
 132         data->keymat_ok = 1;
 133         return 0;
 134 }
 135
 136
 137 static struct wpabuf * eap_ikev2_build_msg(struct eap_ikev2_data *data,
 138                                            struct eap_method_ret *ret, u8 id)
 139 {
 140         struct wpabuf *resp;
 141         u8 flags;
 142         size_t send_len, plen, icv_len = 0;
 143
 144         ret->ignore = FALSE;
 145         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Generating Response");
 146         ret->allowNotifications = TRUE;
 147
 148         flags = 0;
 149         send_len = wpabuf_len(data->out_buf) - data->out_used;
 150         if (1 + send_len > data->fragment_size) {
 151                 send_len = data->fragment_size - 1;
 152                 flags |= IKEV2_FLAGS_MORE_FRAGMENTS;
 153                 if (data->out_used == 0) {
 154                         flags |= IKEV2_FLAGS_LENGTH_INCLUDED;
 155                         send_len -= 4;
 156                 }
 157         }
 158 #ifdef CCNS_PL
 159         /* Some issues figuring out the length of the message if Message Length
 160          * field not included?! */
 161         if (!(flags & IKEV2_FLAGS_LENGTH_INCLUDED))
 162                 flags |= IKEV2_FLAGS_LENGTH_INCLUDED;
 163 #endif /* CCNS_PL */
 164
 165         plen = 1 + send_len;
 166         if (flags & IKEV2_FLAGS_LENGTH_INCLUDED)
 167                 plen += 4;
 168         if (data->keys_ready) {
 169                 const struct ikev2_integ_alg *integ;
 170                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Add Integrity Checksum "
 171                            "Data");
 172                 flags |= IKEV2_FLAGS_ICV_INCLUDED;
 173                 integ = ikev2_get_integ(data->ikev2.proposal.integ);
 174                 if (integ == NULL) {
 175                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Unknown INTEG "
 176                                    "transform / cannot generate ICV");
 177                         return NULL;
 178                 }
 179                 icv_len = integ->hash_len;
 180
 181                 plen += icv_len;
 182         }
 183         resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_IKEV2, plen,
 184                              EAP_CODE_RESPONSE, id);
 185         if (resp == NULL)
 186                 return NULL;
 187
 188         wpabuf_put_u8(resp, flags); /* Flags */
 189         if (flags & IKEV2_FLAGS_LENGTH_INCLUDED)
 190                 wpabuf_put_be32(resp, wpabuf_len(data->out_buf));
 191
 192         wpabuf_put_data(resp, wpabuf_head_u8(data->out_buf) + data->out_used,
 193                         send_len);
 194         data->out_used += send_len;
 195
 196         if (flags & IKEV2_FLAGS_ICV_INCLUDED) {
 197                 const u8 *msg = wpabuf_head(resp);
 198                 size_t len = wpabuf_len(resp);
 199                 ikev2_integ_hash(data->ikev2.proposal.integ,
 200                                  data->ikev2.keys.SK_ar,
 201                                  data->ikev2.keys.SK_integ_len,
 202                                  msg, len, wpabuf_put(resp, icv_len));
 203         }
 204
 205         ret->methodState = METHOD_MAY_CONT;
 206         ret->decision = DECISION_FAIL;
 207
 208         if (data->out_used == wpabuf_len(data->out_buf)) {
 209                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Sending out %lu bytes "
 210                            "(message sent completely)",
 211                            (unsigned long) send_len);
 212                 wpabuf_free(data->out_buf);
 213                 data->out_buf = NULL;
 214                 data->out_used = 0;
 215                 switch (data->ikev2.state) {
 216                 case SA_AUTH:
 217                         /* SA_INIT was sent out, so message have to be
 218                          * integrity protected from now on. */
 219                         data->keys_ready = 1;
 220                         break;
 221                 case IKEV2_DONE:
 222                         ret->methodState = METHOD_DONE;
 223                         if (data->state == FAIL)
 224                                 break;
 225                         ret->decision = DECISION_COND_SUCC;
 226                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Authentication "
 227                                    "completed successfully");
 228                         if (eap_ikev2_peer_keymat(data))
 229                                 break;
 230                         eap_ikev2_state(data, DONE);
 231                         break;
 232                 case IKEV2_FAILED:
 233                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Authentication "
 234                                    "failed");
 235                         ret->methodState = METHOD_DONE;
 236                         ret->decision = DECISION_FAIL;
 237                         break;
 238                 default:
 239                         break;
 240                 }
 241         } else {
 242                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Sending out %lu bytes "
 243                            "(%lu more to send)", (unsigned long) send_len,
 244                            (unsigned long) wpabuf_len(data->out_buf) -
 245                            data->out_used);
 246                 eap_ikev2_state(data, WAIT_FRAG_ACK);
 247         }
 248
 249         return resp;
 250 }
 251
 252
 253 static int eap_ikev2_process_icv(struct eap_ikev2_data *data,
 254                                  const struct wpabuf *reqData,
 255                                  u8 flags, const u8 *pos, const u8 **end)
 256 {
 257         if (flags & IKEV2_FLAGS_ICV_INCLUDED) {
 258                 int icv_len = eap_ikev2_validate_icv(
 259                         data->ikev2.proposal.integ, &data->ikev2.keys, 1,
 260                         reqData, pos, *end);
 261                 if (icv_len < 0)
 262                         return -1;
 263                 /* Hide Integrity Checksum Data from further processing */
 264                 *end -= icv_len;
 265         } else if (data->keys_ready) {
 266                 wpa_printf(MSG_INFO, "EAP-IKEV2: The message should have "
 267                            "included integrity checksum");
 268                 return -1;
 269         }
 270
 271         return 0;
 272 }
 273
 274
 275 static int eap_ikev2_process_cont(struct eap_ikev2_data *data,
 276                                   const u8 *buf, size_t len)
 277 {
 278         /* Process continuation of a pending message */
 279         if (len > wpabuf_tailroom(data->in_buf)) {
 280                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Fragment overflow");
 281                 eap_ikev2_state(data, FAIL);
 282                 return -1;
 283         }
 284
 285         wpabuf_put_data(data->in_buf, buf, len);
 286         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Received %lu bytes, waiting "
 287                    "for %lu bytes more", (unsigned long) len,
 288                    (unsigned long) wpabuf_tailroom(data->in_buf));
 289
 290         return 0;
 291 }
 292
 293
 294 static struct wpabuf * eap_ikev2_process_fragment(struct eap_ikev2_data *data,
 295                                                   struct eap_method_ret *ret,
 296                                                   u8 id, u8 flags,
 297                                                   u32 message_length,
 298                                                   const u8 *buf, size_t len)
 299 {
 300         /* Process a fragment that is not the last one of the message */
 301         if (data->in_buf == NULL && !(flags & IKEV2_FLAGS_LENGTH_INCLUDED)) {
 302                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: No Message Length field in "
 303                            "a fragmented packet");
 304                 ret->ignore = TRUE;
 305                 return NULL;
 306         }
 307
 308         if (data->in_buf == NULL) {
 309                 /* First fragment of the message */
 310                 data->in_buf = wpabuf_alloc(message_length);
 311                 if (data->in_buf == NULL) {
 312                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: No memory for "
 313                                    "message");
 314                         ret->ignore = TRUE;
 315                         return NULL;
 316                 }
 317                 wpabuf_put_data(data->in_buf, buf, len);
 318                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Received %lu bytes in first "
 319                            "fragment, waiting for %lu bytes more",
 320                            (unsigned long) len,
 321                            (unsigned long) wpabuf_tailroom(data->in_buf));
 322         }
 323
 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) < 0) {
 356                 ret->ignore = TRUE;
 357                 return NULL;
 358         }
 359
 360         if (flags & IKEV2_FLAGS_LENGTH_INCLUDED) {
 361                 if (end - pos < 4) {
 362                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Message underflow");
 363                         ret->ignore = TRUE;
 364                         return NULL;
 365                 }
 366                 message_length = WPA_GET_BE32(pos);
 367                 pos += 4;
 368
 369                 if (message_length < (u32) (end - pos)) {
 370                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Invalid Message "
 371                                    "Length (%d; %ld remaining in this msg)",
 372                                    message_length, (long) (end - pos));
 373                         ret->ignore = TRUE;
 374                         return NULL;
 375                 }
 376         }
 377
 378         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Received packet: Flags 0x%x "
 379                    "Message Length %u", flags, message_length);
 380
 381         if (data->state == WAIT_FRAG_ACK) {
 382 #ifdef CCNS_PL
 383                 if (len > 1) /* Empty Flags field included in ACK */
 384 #else /* CCNS_PL */
 385                 if (len != 0)
 386 #endif /* CCNS_PL */
 387                 {
 388                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Unexpected payload "
 389                                    "in WAIT_FRAG_ACK state");
 390                         ret->ignore = TRUE;
 391                         return NULL;
 392                 }
 393                 wpa_printf(MSG_DEBUG, "EAP-IKEV2: Fragment acknowledged");
 394                 eap_ikev2_state(data, PROC_MSG);
 395                 return eap_ikev2_build_msg(data, ret, id);
 396         }
 397
 398         if (data->in_buf && eap_ikev2_process_cont(data, pos, end - pos) < 0) {
 399                 ret->ignore = TRUE;
 400                 return NULL;
 401         }
 402
 403         if (flags & IKEV2_FLAGS_MORE_FRAGMENTS) {
 404                 return eap_ikev2_process_fragment(data, ret, id, flags,
 405                                                   message_length, pos,
 406                                                   end - pos);
 407         }
 408
 409         if (data->in_buf == NULL) {
 410                 /* Wrap unfragmented messages as wpabuf without extra copy */
 411                 wpabuf_set(&tmpbuf, pos, end - pos);
 412                 data->in_buf = &tmpbuf;
 413         }
 414
 415         if (ikev2_responder_process(&data->ikev2, data->in_buf) < 0) {
 416                 if (data->in_buf == &tmpbuf)
 417                         data->in_buf = NULL;
 418                 eap_ikev2_state(data, FAIL);
 419                 return NULL;
 420         }
 421
 422         if (data->in_buf != &tmpbuf)
 423                 wpabuf_free(data->in_buf);
 424         data->in_buf = NULL;
 425
 426         if (data->out_buf == NULL) {
 427                 data->out_buf = ikev2_responder_build(&data->ikev2);
 428                 if (data->out_buf == NULL) {
 429                         wpa_printf(MSG_DEBUG, "EAP-IKEV2: Failed to generate "
 430                                    "IKEv2 message");
 431                         return NULL;
 432                 }
 433                 data->out_used = 0;
 434         }
 435
 436         eap_ikev2_state(data, PROC_MSG);
 437         return eap_ikev2_build_msg(data, ret, id);
 438 }
 439
 440
 441 static Boolean eap_ikev2_isKeyAvailable(struct eap_sm *sm, void *priv)
 442 {
 443         struct eap_ikev2_data *data = priv;
 444         return data->state == DONE && data->keymat_ok;
 445 }
 446
 447
 448 static u8 * eap_ikev2_getKey(struct eap_sm *sm, void *priv, size_t *len)
 449 {
 450         struct eap_ikev2_data *data = priv;
 451         u8 *key;
 452
 453         if (data->state != DONE || !data->keymat_ok)
 454                 return NULL;
 455
 456         key = os_malloc(EAP_MSK_LEN);
 457         if (key) {
 458                 os_memcpy(key, data->keymat, EAP_MSK_LEN);
 459                 *len = EAP_MSK_LEN;
 460         }
 461
 462         return key;
 463 }
 464
 465
 466 static u8 * eap_ikev2_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
 467 {
 468         struct eap_ikev2_data *data = priv;
 469         u8 *key;
 470
 471         if (data->state != DONE || !data->keymat_ok)
 472                 return NULL;
 473
 474         key = os_malloc(EAP_EMSK_LEN);
 475         if (key) {
 476                 os_memcpy(key, data->keymat + EAP_MSK_LEN, EAP_EMSK_LEN);
 477                 *len = EAP_EMSK_LEN;
 478         }
 479
 480         return key;
 481 }
 482
 483
 484 int eap_peer_ikev2_register(void)
 485 {
 486         struct eap_method *eap;
 487         int ret;
 488
 489         eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
 490                                     EAP_VENDOR_IETF, EAP_TYPE_IKEV2,
 491                                     "IKEV2");
 492         if (eap == NULL)
 493                 return -1;
 494
 495         eap->init = eap_ikev2_init;
 496         eap->deinit = eap_ikev2_deinit;
 497         eap->process = eap_ikev2_process;
 498         eap->isKeyAvailable = eap_ikev2_isKeyAvailable;
 499         eap->getKey = eap_ikev2_getKey;
 500         eap->get_emsk = eap_ikev2_get_emsk;
 501
 502         ret = eap_peer_method_register(eap);
 503         if (ret)
 504                 eap_peer_method_free(eap);
 505         return ret;
 506 }