| 1 | /* |
| 2 | * hostapd / EAP-SAKE (RFC 4763) server |
| 3 | * Copyright (c) 2006-2007, 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 "crypto/random.h" |
| 13 | #include "eap_server/eap_i.h" |
| 14 | #include "eap_common/eap_sake_common.h" |
| 15 | |
| 16 | |
| 17 | struct eap_sake_data { |
| 18 | enum { IDENTITY, CHALLENGE, CONFIRM, SUCCESS, FAILURE } state; |
| 19 | u8 rand_s[EAP_SAKE_RAND_LEN]; |
| 20 | u8 rand_p[EAP_SAKE_RAND_LEN]; |
| 21 | struct { |
| 22 | u8 auth[EAP_SAKE_TEK_AUTH_LEN]; |
| 23 | u8 cipher[EAP_SAKE_TEK_CIPHER_LEN]; |
| 24 | } tek; |
| 25 | u8 msk[EAP_MSK_LEN]; |
| 26 | u8 emsk[EAP_EMSK_LEN]; |
| 27 | u8 session_id; |
| 28 | u8 *peerid; |
| 29 | size_t peerid_len; |
| 30 | }; |
| 31 | |
| 32 | |
| 33 | static const char * eap_sake_state_txt(int state) |
| 34 | { |
| 35 | switch (state) { |
| 36 | case IDENTITY: |
| 37 | return "IDENTITY"; |
| 38 | case CHALLENGE: |
| 39 | return "CHALLENGE"; |
| 40 | case CONFIRM: |
| 41 | return "CONFIRM"; |
| 42 | case SUCCESS: |
| 43 | return "SUCCESS"; |
| 44 | case FAILURE: |
| 45 | return "FAILURE"; |
| 46 | default: |
| 47 | return "?"; |
| 48 | } |
| 49 | } |
| 50 | |
| 51 | |
| 52 | static void eap_sake_state(struct eap_sake_data *data, int state) |
| 53 | { |
| 54 | wpa_printf(MSG_DEBUG, "EAP-SAKE: %s -> %s", |
| 55 | eap_sake_state_txt(data->state), |
| 56 | eap_sake_state_txt(state)); |
| 57 | data->state = state; |
| 58 | } |
| 59 | |
| 60 | |
| 61 | static void * eap_sake_init(struct eap_sm *sm) |
| 62 | { |
| 63 | struct eap_sake_data *data; |
| 64 | |
| 65 | data = os_zalloc(sizeof(*data)); |
| 66 | if (data == NULL) |
| 67 | return NULL; |
| 68 | data->state = CHALLENGE; |
| 69 | |
| 70 | if (os_get_random(&data->session_id, 1)) { |
| 71 | wpa_printf(MSG_ERROR, "EAP-SAKE: Failed to get random data"); |
| 72 | os_free(data); |
| 73 | return NULL; |
| 74 | } |
| 75 | wpa_printf(MSG_DEBUG, "EAP-SAKE: Initialized Session ID %d", |
| 76 | data->session_id); |
| 77 | |
| 78 | return data; |
| 79 | } |
| 80 | |
| 81 | |
| 82 | static void eap_sake_reset(struct eap_sm *sm, void *priv) |
| 83 | { |
| 84 | struct eap_sake_data *data = priv; |
| 85 | os_free(data->peerid); |
| 86 | os_free(data); |
| 87 | } |
| 88 | |
| 89 | |
| 90 | static struct wpabuf * eap_sake_build_msg(struct eap_sake_data *data, |
| 91 | u8 id, size_t length, u8 subtype) |
| 92 | { |
| 93 | struct eap_sake_hdr *sake; |
| 94 | struct wpabuf *msg; |
| 95 | size_t plen; |
| 96 | |
| 97 | plen = sizeof(struct eap_sake_hdr) + length; |
| 98 | |
| 99 | msg = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_SAKE, plen, |
| 100 | EAP_CODE_REQUEST, id); |
| 101 | if (msg == NULL) { |
| 102 | wpa_printf(MSG_ERROR, "EAP-SAKE: Failed to allocate memory " |
| 103 | "request"); |
| 104 | return NULL; |
| 105 | } |
| 106 | |
| 107 | sake = wpabuf_put(msg, sizeof(*sake)); |
| 108 | sake->version = EAP_SAKE_VERSION; |
| 109 | sake->session_id = data->session_id; |
| 110 | sake->subtype = subtype; |
| 111 | |
| 112 | return msg; |
| 113 | } |
| 114 | |
| 115 | |
| 116 | static struct wpabuf * eap_sake_build_identity(struct eap_sm *sm, |
| 117 | struct eap_sake_data *data, |
| 118 | u8 id) |
| 119 | { |
| 120 | struct wpabuf *msg; |
| 121 | size_t plen; |
| 122 | |
| 123 | wpa_printf(MSG_DEBUG, "EAP-SAKE: Request/Identity"); |
| 124 | |
| 125 | plen = 4; |
| 126 | plen += 2 + sm->server_id_len; |
| 127 | msg = eap_sake_build_msg(data, id, plen, EAP_SAKE_SUBTYPE_IDENTITY); |
| 128 | if (msg == NULL) { |
| 129 | data->state = FAILURE; |
| 130 | return NULL; |
| 131 | } |
| 132 | |
| 133 | wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_PERM_ID_REQ"); |
| 134 | eap_sake_add_attr(msg, EAP_SAKE_AT_PERM_ID_REQ, NULL, 2); |
| 135 | |
| 136 | wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_SERVERID"); |
| 137 | eap_sake_add_attr(msg, EAP_SAKE_AT_SERVERID, |
| 138 | sm->server_id, sm->server_id_len); |
| 139 | |
| 140 | return msg; |
| 141 | } |
| 142 | |
| 143 | |
| 144 | static struct wpabuf * eap_sake_build_challenge(struct eap_sm *sm, |
| 145 | struct eap_sake_data *data, |
| 146 | u8 id) |
| 147 | { |
| 148 | struct wpabuf *msg; |
| 149 | size_t plen; |
| 150 | |
| 151 | wpa_printf(MSG_DEBUG, "EAP-SAKE: Request/Challenge"); |
| 152 | |
| 153 | if (random_get_bytes(data->rand_s, EAP_SAKE_RAND_LEN)) { |
| 154 | wpa_printf(MSG_ERROR, "EAP-SAKE: Failed to get random data"); |
| 155 | data->state = FAILURE; |
| 156 | return NULL; |
| 157 | } |
| 158 | wpa_hexdump(MSG_MSGDUMP, "EAP-SAKE: RAND_S (server rand)", |
| 159 | data->rand_s, EAP_SAKE_RAND_LEN); |
| 160 | |
| 161 | plen = 2 + EAP_SAKE_RAND_LEN + 2 + sm->server_id_len; |
| 162 | msg = eap_sake_build_msg(data, id, plen, EAP_SAKE_SUBTYPE_CHALLENGE); |
| 163 | if (msg == NULL) { |
| 164 | data->state = FAILURE; |
| 165 | return NULL; |
| 166 | } |
| 167 | |
| 168 | wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_RAND_S"); |
| 169 | eap_sake_add_attr(msg, EAP_SAKE_AT_RAND_S, |
| 170 | data->rand_s, EAP_SAKE_RAND_LEN); |
| 171 | |
| 172 | wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_SERVERID"); |
| 173 | eap_sake_add_attr(msg, EAP_SAKE_AT_SERVERID, |
| 174 | sm->server_id, sm->server_id_len); |
| 175 | |
| 176 | return msg; |
| 177 | } |
| 178 | |
| 179 | |
| 180 | static struct wpabuf * eap_sake_build_confirm(struct eap_sm *sm, |
| 181 | struct eap_sake_data *data, |
| 182 | u8 id) |
| 183 | { |
| 184 | struct wpabuf *msg; |
| 185 | u8 *mic; |
| 186 | |
| 187 | wpa_printf(MSG_DEBUG, "EAP-SAKE: Request/Confirm"); |
| 188 | |
| 189 | msg = eap_sake_build_msg(data, id, 2 + EAP_SAKE_MIC_LEN, |
| 190 | EAP_SAKE_SUBTYPE_CONFIRM); |
| 191 | if (msg == NULL) { |
| 192 | data->state = FAILURE; |
| 193 | return NULL; |
| 194 | } |
| 195 | |
| 196 | wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_MIC_S"); |
| 197 | wpabuf_put_u8(msg, EAP_SAKE_AT_MIC_S); |
| 198 | wpabuf_put_u8(msg, 2 + EAP_SAKE_MIC_LEN); |
| 199 | mic = wpabuf_put(msg, EAP_SAKE_MIC_LEN); |
| 200 | if (eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p, |
| 201 | sm->server_id, sm->server_id_len, |
| 202 | data->peerid, data->peerid_len, 0, |
| 203 | wpabuf_head(msg), wpabuf_len(msg), mic, mic)) |
| 204 | { |
| 205 | wpa_printf(MSG_INFO, "EAP-SAKE: Failed to compute MIC"); |
| 206 | data->state = FAILURE; |
| 207 | os_free(msg); |
| 208 | return NULL; |
| 209 | } |
| 210 | |
| 211 | return msg; |
| 212 | } |
| 213 | |
| 214 | |
| 215 | static struct wpabuf * eap_sake_buildReq(struct eap_sm *sm, void *priv, u8 id) |
| 216 | { |
| 217 | struct eap_sake_data *data = priv; |
| 218 | |
| 219 | switch (data->state) { |
| 220 | case IDENTITY: |
| 221 | return eap_sake_build_identity(sm, data, id); |
| 222 | case CHALLENGE: |
| 223 | return eap_sake_build_challenge(sm, data, id); |
| 224 | case CONFIRM: |
| 225 | return eap_sake_build_confirm(sm, data, id); |
| 226 | default: |
| 227 | wpa_printf(MSG_DEBUG, "EAP-SAKE: Unknown state %d in buildReq", |
| 228 | data->state); |
| 229 | break; |
| 230 | } |
| 231 | return NULL; |
| 232 | } |
| 233 | |
| 234 | |
| 235 | static Boolean eap_sake_check(struct eap_sm *sm, void *priv, |
| 236 | struct wpabuf *respData) |
| 237 | { |
| 238 | struct eap_sake_data *data = priv; |
| 239 | struct eap_sake_hdr *resp; |
| 240 | size_t len; |
| 241 | u8 version, session_id, subtype; |
| 242 | const u8 *pos; |
| 243 | |
| 244 | pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_SAKE, respData, &len); |
| 245 | if (pos == NULL || len < sizeof(struct eap_sake_hdr)) { |
| 246 | wpa_printf(MSG_INFO, "EAP-SAKE: Invalid frame"); |
| 247 | return TRUE; |
| 248 | } |
| 249 | |
| 250 | resp = (struct eap_sake_hdr *) pos; |
| 251 | version = resp->version; |
| 252 | session_id = resp->session_id; |
| 253 | subtype = resp->subtype; |
| 254 | |
| 255 | if (version != EAP_SAKE_VERSION) { |
| 256 | wpa_printf(MSG_INFO, "EAP-SAKE: Unknown version %d", version); |
| 257 | return TRUE; |
| 258 | } |
| 259 | |
| 260 | if (session_id != data->session_id) { |
| 261 | wpa_printf(MSG_INFO, "EAP-SAKE: Session ID mismatch (%d,%d)", |
| 262 | session_id, data->session_id); |
| 263 | return TRUE; |
| 264 | } |
| 265 | |
| 266 | wpa_printf(MSG_DEBUG, "EAP-SAKE: Received frame: subtype=%d", subtype); |
| 267 | |
| 268 | if (data->state == IDENTITY && subtype == EAP_SAKE_SUBTYPE_IDENTITY) |
| 269 | return FALSE; |
| 270 | |
| 271 | if (data->state == CHALLENGE && subtype == EAP_SAKE_SUBTYPE_CHALLENGE) |
| 272 | return FALSE; |
| 273 | |
| 274 | if (data->state == CONFIRM && subtype == EAP_SAKE_SUBTYPE_CONFIRM) |
| 275 | return FALSE; |
| 276 | |
| 277 | if (subtype == EAP_SAKE_SUBTYPE_AUTH_REJECT) |
| 278 | return FALSE; |
| 279 | |
| 280 | wpa_printf(MSG_INFO, "EAP-SAKE: Unexpected subtype=%d in state=%d", |
| 281 | subtype, data->state); |
| 282 | |
| 283 | return TRUE; |
| 284 | } |
| 285 | |
| 286 | |
| 287 | static void eap_sake_process_identity(struct eap_sm *sm, |
| 288 | struct eap_sake_data *data, |
| 289 | const struct wpabuf *respData, |
| 290 | const u8 *payload, size_t payloadlen) |
| 291 | { |
| 292 | if (data->state != IDENTITY) |
| 293 | return; |
| 294 | |
| 295 | wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Response/Identity"); |
| 296 | /* TODO: update identity and select new user data */ |
| 297 | eap_sake_state(data, CHALLENGE); |
| 298 | } |
| 299 | |
| 300 | |
| 301 | static void eap_sake_process_challenge(struct eap_sm *sm, |
| 302 | struct eap_sake_data *data, |
| 303 | const struct wpabuf *respData, |
| 304 | const u8 *payload, size_t payloadlen) |
| 305 | { |
| 306 | struct eap_sake_parse_attr attr; |
| 307 | u8 mic_p[EAP_SAKE_MIC_LEN]; |
| 308 | |
| 309 | if (data->state != CHALLENGE) |
| 310 | return; |
| 311 | |
| 312 | wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Response/Challenge"); |
| 313 | |
| 314 | if (eap_sake_parse_attributes(payload, payloadlen, &attr)) |
| 315 | return; |
| 316 | |
| 317 | if (!attr.rand_p || !attr.mic_p) { |
| 318 | wpa_printf(MSG_INFO, "EAP-SAKE: Response/Challenge did not " |
| 319 | "include AT_RAND_P or AT_MIC_P"); |
| 320 | return; |
| 321 | } |
| 322 | |
| 323 | os_memcpy(data->rand_p, attr.rand_p, EAP_SAKE_RAND_LEN); |
| 324 | |
| 325 | os_free(data->peerid); |
| 326 | data->peerid = NULL; |
| 327 | data->peerid_len = 0; |
| 328 | if (attr.peerid) { |
| 329 | data->peerid = os_malloc(attr.peerid_len); |
| 330 | if (data->peerid == NULL) |
| 331 | return; |
| 332 | os_memcpy(data->peerid, attr.peerid, attr.peerid_len); |
| 333 | data->peerid_len = attr.peerid_len; |
| 334 | } |
| 335 | |
| 336 | if (sm->user == NULL || sm->user->password == NULL || |
| 337 | sm->user->password_len != 2 * EAP_SAKE_ROOT_SECRET_LEN) { |
| 338 | wpa_printf(MSG_INFO, "EAP-SAKE: Plaintext password with " |
| 339 | "%d-byte key not configured", |
| 340 | 2 * EAP_SAKE_ROOT_SECRET_LEN); |
| 341 | data->state = FAILURE; |
| 342 | return; |
| 343 | } |
| 344 | eap_sake_derive_keys(sm->user->password, |
| 345 | sm->user->password + EAP_SAKE_ROOT_SECRET_LEN, |
| 346 | data->rand_s, data->rand_p, |
| 347 | (u8 *) &data->tek, data->msk, data->emsk); |
| 348 | |
| 349 | eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p, |
| 350 | sm->server_id, sm->server_id_len, |
| 351 | data->peerid, data->peerid_len, 1, |
| 352 | wpabuf_head(respData), wpabuf_len(respData), |
| 353 | attr.mic_p, mic_p); |
| 354 | if (os_memcmp(attr.mic_p, mic_p, EAP_SAKE_MIC_LEN) != 0) { |
| 355 | wpa_printf(MSG_INFO, "EAP-SAKE: Incorrect AT_MIC_P"); |
| 356 | eap_sake_state(data, FAILURE); |
| 357 | return; |
| 358 | } |
| 359 | |
| 360 | eap_sake_state(data, CONFIRM); |
| 361 | } |
| 362 | |
| 363 | |
| 364 | static void eap_sake_process_confirm(struct eap_sm *sm, |
| 365 | struct eap_sake_data *data, |
| 366 | const struct wpabuf *respData, |
| 367 | const u8 *payload, size_t payloadlen) |
| 368 | { |
| 369 | struct eap_sake_parse_attr attr; |
| 370 | u8 mic_p[EAP_SAKE_MIC_LEN]; |
| 371 | |
| 372 | if (data->state != CONFIRM) |
| 373 | return; |
| 374 | |
| 375 | wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Response/Confirm"); |
| 376 | |
| 377 | if (eap_sake_parse_attributes(payload, payloadlen, &attr)) |
| 378 | return; |
| 379 | |
| 380 | if (!attr.mic_p) { |
| 381 | wpa_printf(MSG_INFO, "EAP-SAKE: Response/Confirm did not " |
| 382 | "include AT_MIC_P"); |
| 383 | return; |
| 384 | } |
| 385 | |
| 386 | eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p, |
| 387 | sm->server_id, sm->server_id_len, |
| 388 | data->peerid, data->peerid_len, 1, |
| 389 | wpabuf_head(respData), wpabuf_len(respData), |
| 390 | attr.mic_p, mic_p); |
| 391 | if (os_memcmp(attr.mic_p, mic_p, EAP_SAKE_MIC_LEN) != 0) { |
| 392 | wpa_printf(MSG_INFO, "EAP-SAKE: Incorrect AT_MIC_P"); |
| 393 | eap_sake_state(data, FAILURE); |
| 394 | } else |
| 395 | eap_sake_state(data, SUCCESS); |
| 396 | } |
| 397 | |
| 398 | |
| 399 | static void eap_sake_process_auth_reject(struct eap_sm *sm, |
| 400 | struct eap_sake_data *data, |
| 401 | const struct wpabuf *respData, |
| 402 | const u8 *payload, size_t payloadlen) |
| 403 | { |
| 404 | wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Response/Auth-Reject"); |
| 405 | eap_sake_state(data, FAILURE); |
| 406 | } |
| 407 | |
| 408 | |
| 409 | static void eap_sake_process(struct eap_sm *sm, void *priv, |
| 410 | struct wpabuf *respData) |
| 411 | { |
| 412 | struct eap_sake_data *data = priv; |
| 413 | struct eap_sake_hdr *resp; |
| 414 | u8 subtype; |
| 415 | size_t len; |
| 416 | const u8 *pos, *end; |
| 417 | |
| 418 | pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_SAKE, respData, &len); |
| 419 | if (pos == NULL || len < sizeof(struct eap_sake_hdr)) |
| 420 | return; |
| 421 | |
| 422 | resp = (struct eap_sake_hdr *) pos; |
| 423 | end = pos + len; |
| 424 | subtype = resp->subtype; |
| 425 | pos = (u8 *) (resp + 1); |
| 426 | |
| 427 | wpa_hexdump(MSG_DEBUG, "EAP-SAKE: Received attributes", |
| 428 | pos, end - pos); |
| 429 | |
| 430 | switch (subtype) { |
| 431 | case EAP_SAKE_SUBTYPE_IDENTITY: |
| 432 | eap_sake_process_identity(sm, data, respData, pos, end - pos); |
| 433 | break; |
| 434 | case EAP_SAKE_SUBTYPE_CHALLENGE: |
| 435 | eap_sake_process_challenge(sm, data, respData, pos, end - pos); |
| 436 | break; |
| 437 | case EAP_SAKE_SUBTYPE_CONFIRM: |
| 438 | eap_sake_process_confirm(sm, data, respData, pos, end - pos); |
| 439 | break; |
| 440 | case EAP_SAKE_SUBTYPE_AUTH_REJECT: |
| 441 | eap_sake_process_auth_reject(sm, data, respData, pos, |
| 442 | end - pos); |
| 443 | break; |
| 444 | } |
| 445 | } |
| 446 | |
| 447 | |
| 448 | static Boolean eap_sake_isDone(struct eap_sm *sm, void *priv) |
| 449 | { |
| 450 | struct eap_sake_data *data = priv; |
| 451 | return data->state == SUCCESS || data->state == FAILURE; |
| 452 | } |
| 453 | |
| 454 | |
| 455 | static u8 * eap_sake_getKey(struct eap_sm *sm, void *priv, size_t *len) |
| 456 | { |
| 457 | struct eap_sake_data *data = priv; |
| 458 | u8 *key; |
| 459 | |
| 460 | if (data->state != SUCCESS) |
| 461 | return NULL; |
| 462 | |
| 463 | key = os_malloc(EAP_MSK_LEN); |
| 464 | if (key == NULL) |
| 465 | return NULL; |
| 466 | os_memcpy(key, data->msk, EAP_MSK_LEN); |
| 467 | *len = EAP_MSK_LEN; |
| 468 | |
| 469 | return key; |
| 470 | } |
| 471 | |
| 472 | |
| 473 | static u8 * eap_sake_get_emsk(struct eap_sm *sm, void *priv, size_t *len) |
| 474 | { |
| 475 | struct eap_sake_data *data = priv; |
| 476 | u8 *key; |
| 477 | |
| 478 | if (data->state != SUCCESS) |
| 479 | return NULL; |
| 480 | |
| 481 | key = os_malloc(EAP_EMSK_LEN); |
| 482 | if (key == NULL) |
| 483 | return NULL; |
| 484 | os_memcpy(key, data->emsk, EAP_EMSK_LEN); |
| 485 | *len = EAP_EMSK_LEN; |
| 486 | |
| 487 | return key; |
| 488 | } |
| 489 | |
| 490 | |
| 491 | static Boolean eap_sake_isSuccess(struct eap_sm *sm, void *priv) |
| 492 | { |
| 493 | struct eap_sake_data *data = priv; |
| 494 | return data->state == SUCCESS; |
| 495 | } |
| 496 | |
| 497 | |
| 498 | int eap_server_sake_register(void) |
| 499 | { |
| 500 | struct eap_method *eap; |
| 501 | int ret; |
| 502 | |
| 503 | eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION, |
| 504 | EAP_VENDOR_IETF, EAP_TYPE_SAKE, "SAKE"); |
| 505 | if (eap == NULL) |
| 506 | return -1; |
| 507 | |
| 508 | eap->init = eap_sake_init; |
| 509 | eap->reset = eap_sake_reset; |
| 510 | eap->buildReq = eap_sake_buildReq; |
| 511 | eap->check = eap_sake_check; |
| 512 | eap->process = eap_sake_process; |
| 513 | eap->isDone = eap_sake_isDone; |
| 514 | eap->getKey = eap_sake_getKey; |
| 515 | eap->isSuccess = eap_sake_isSuccess; |
| 516 | eap->get_emsk = eap_sake_get_emsk; |
| 517 | |
| 518 | ret = eap_server_method_register(eap); |
| 519 | if (ret) |
| 520 | eap_server_method_free(eap); |
| 521 | return ret; |
| 522 | } |