1 /* 2 * EAP-IKEv2 peer (RFC 5106) 3 * Copyright (c) 2007, Jouni Malinen <j (at) 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 } 507
