1 /* 2 * EAP-TLS/PEAP/TTLS/FAST server common functions 3 * Copyright (c) 2004-2009, 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/sha1.h" 13 #include "crypto/tls.h" 14 #include "eap_i.h" 15 #include "eap_tls_common.h" 16 17 18 static void eap_server_tls_free_in_buf(struct eap_ssl_data *data); 19 20 21 struct wpabuf * eap_tls_msg_alloc(EapType type, size_t payload_len, 22 u8 code, u8 identifier) 23 { 24 if (type == EAP_UNAUTH_TLS_TYPE) 25 return eap_msg_alloc(EAP_VENDOR_UNAUTH_TLS, 26 EAP_VENDOR_TYPE_UNAUTH_TLS, payload_len, 27 code, identifier); 28 else if (type == EAP_WFA_UNAUTH_TLS_TYPE) 29 return eap_msg_alloc(EAP_VENDOR_WFA_NEW, 30 EAP_VENDOR_WFA_UNAUTH_TLS, payload_len, 31 code, identifier); 32 return eap_msg_alloc(EAP_VENDOR_IETF, type, payload_len, code, 33 identifier); 34 } 35 36 37 #ifdef CONFIG_TLS_INTERNAL 38 static void eap_server_tls_log_cb(void *ctx, const char *msg) 39 { 40 struct eap_sm *sm = ctx; 41 eap_log_msg(sm, "TLS: %s", msg); 42 } 43 #endif /* CONFIG_TLS_INTERNAL */ 44 45 46 int eap_server_tls_ssl_init(struct eap_sm *sm, struct eap_ssl_data *data, 47 int verify_peer, int eap_type) 48 { 49 u8 session_ctx[8]; 50 unsigned int flags = sm->tls_flags; 51 52 if (sm->ssl_ctx == NULL) { 53 wpa_printf(MSG_ERROR, "TLS context not initialized - cannot use TLS-based EAP method"); 54 return -1; 55 } 56 57 data->eap = sm; 58 data->phase2 = sm->init_phase2; 59 60 data->conn = tls_connection_init(sm->ssl_ctx); 61 if (data->conn == NULL) { 62 wpa_printf(MSG_INFO, "SSL: Failed to initialize new TLS " 63 "connection"); 64 return -1; 65 } 66 67 #ifdef CONFIG_TLS_INTERNAL 68 tls_connection_set_log_cb(data->conn, eap_server_tls_log_cb, sm); 69 #ifdef CONFIG_TESTING_OPTIONS 70 tls_connection_set_test_flags(data->conn, sm->tls_test_flags); 71 #endif /* CONFIG_TESTING_OPTIONS */ 72 #endif /* CONFIG_TLS_INTERNAL */ 73 74 if (eap_type != EAP_TYPE_FAST) 75 flags |= TLS_CONN_DISABLE_SESSION_TICKET; 76 os_memcpy(session_ctx, "hostapd", 7); 77 session_ctx[7] = (u8) eap_type; 78 if (tls_connection_set_verify(sm->ssl_ctx, data->conn, verify_peer, 79 flags, session_ctx, 80 sizeof(session_ctx))) { 81 wpa_printf(MSG_INFO, "SSL: Failed to configure verification " 82 "of TLS peer certificate"); 83 tls_connection_deinit(sm->ssl_ctx, data->conn); 84 data->conn = NULL; 85 return -1; 86 } 87 88 data->tls_out_limit = sm->fragment_size > 0 ? sm->fragment_size : 1398; 89 if (data->phase2) { 90 /* Limit the fragment size in the inner TLS authentication 91 * since the outer authentication with EAP-PEAP does not yet 92 * support fragmentation */ 93 if (data->tls_out_limit > 100) 94 data->tls_out_limit -= 100; 95 } 96 return 0; 97 } 98 99 100 void eap_server_tls_ssl_deinit(struct eap_sm *sm, struct eap_ssl_data *data) 101 { 102 tls_connection_deinit(sm->ssl_ctx, data->conn); 103 eap_server_tls_free_in_buf(data); 104 wpabuf_free(data->tls_out); 105 data->tls_out = NULL; 106 } 107 108 109 u8 * eap_server_tls_derive_key(struct eap_sm *sm, struct eap_ssl_data *data, 110 const char *label, size_t len) 111 { 112 u8 *out; 113 114 out = os_malloc(len); 115 if (out == NULL) 116 return NULL; 117 118 if (tls_connection_export_key(sm->ssl_ctx, data->conn, label, out, 119 len)) { 120 os_free(out); 121 return NULL; 122 } 123 124 return out; 125 } 126 127 128 /** 129 * eap_server_tls_derive_session_id - Derive a Session-Id based on TLS data 130 * @sm: Pointer to EAP state machine allocated with eap_peer_sm_init() 131 * @data: Data for TLS processing 132 * @eap_type: EAP method used in Phase 1 (EAP_TYPE_TLS/PEAP/TTLS/FAST) 133 * @len: Pointer to length of the session ID generated 134 * Returns: Pointer to allocated Session-Id on success or %NULL on failure 135 * 136 * This function derive the Session-Id based on the TLS session data 137 * (client/server random and method type). 138 * 139 * The caller is responsible for freeing the returned buffer. 140 */ 141 u8 * eap_server_tls_derive_session_id(struct eap_sm *sm, 142 struct eap_ssl_data *data, u8 eap_type, 143 size_t *len) 144 { 145 struct tls_random keys; 146 u8 *out; 147 148 if (eap_type == EAP_TYPE_TLS && data->tls_v13) { 149 *len = 64; 150 return eap_server_tls_derive_key(sm, data, 151 "EXPORTER_EAP_TLS_Session-Id", 152 64); 153 } 154 155 if (tls_connection_get_random(sm->ssl_ctx, data->conn, &keys)) 156 return NULL; 157 158 if (keys.client_random == NULL || keys.server_random == NULL) 159 return NULL; 160 161 *len = 1 + keys.client_random_len + keys.server_random_len; 162 out = os_malloc(*len); 163 if (out == NULL) 164 return NULL; 165 166 /* Session-Id = EAP type || client.random || server.random */ 167 out[0] = eap_type; 168 os_memcpy(out + 1, keys.client_random, keys.client_random_len); 169 os_memcpy(out + 1 + keys.client_random_len, keys.server_random, 170 keys.server_random_len); 171 172 return out; 173 } 174 175 176 struct wpabuf * eap_server_tls_build_msg(struct eap_ssl_data *data, 177 int eap_type, int version, u8 id) 178 { 179 struct wpabuf *req; 180 u8 flags; 181 size_t send_len, plen; 182 183 wpa_printf(MSG_DEBUG, "SSL: Generating Request"); 184 if (data->tls_out == NULL) { 185 wpa_printf(MSG_ERROR, "SSL: tls_out NULL in %s", __func__); 186 return NULL; 187 } 188 189 flags = version; 190 send_len = wpabuf_len(data->tls_out) - data->tls_out_pos; 191 if (1 + send_len > data->tls_out_limit) { 192 send_len = data->tls_out_limit - 1; 193 flags |= EAP_TLS_FLAGS_MORE_FRAGMENTS; 194 if (data->tls_out_pos == 0) { 195 flags |= EAP_TLS_FLAGS_LENGTH_INCLUDED; 196 send_len -= 4; 197 } 198 } 199 200 plen = 1 + send_len; 201 if (flags & EAP_TLS_FLAGS_LENGTH_INCLUDED) 202 plen += 4; 203 204 req = eap_tls_msg_alloc(eap_type, plen, EAP_CODE_REQUEST, id); 205 if (req == NULL) 206 return NULL; 207 208 wpabuf_put_u8(req, flags); /* Flags */ 209 if (flags & EAP_TLS_FLAGS_LENGTH_INCLUDED) 210 wpabuf_put_be32(req, wpabuf_len(data->tls_out)); 211 212 wpabuf_put_data(req, wpabuf_head_u8(data->tls_out) + data->tls_out_pos, 213 send_len); 214 data->tls_out_pos += send_len; 215 216 if (data->tls_out_pos == wpabuf_len(data->tls_out)) { 217 wpa_printf(MSG_DEBUG, "SSL: Sending out %lu bytes " 218 "(message sent completely)", 219 (unsigned long) send_len); 220 wpabuf_free(data->tls_out); 221 data->tls_out = NULL; 222 data->tls_out_pos = 0; 223 data->state = MSG; 224 } else { 225 wpa_printf(MSG_DEBUG, "SSL: Sending out %lu bytes " 226 "(%lu more to send)", (unsigned long) send_len, 227 (unsigned long) wpabuf_len(data->tls_out) - 228 data->tls_out_pos); 229 data->state = WAIT_FRAG_ACK; 230 } 231 232 return req; 233 } 234 235 236 struct wpabuf * eap_server_tls_build_ack(u8 id, int eap_type, int version) 237 { 238 struct wpabuf *req; 239 240 req = eap_tls_msg_alloc(eap_type, 1, EAP_CODE_REQUEST, id); 241 if (req == NULL) 242 return NULL; 243 wpa_printf(MSG_DEBUG, "SSL: Building ACK"); 244 wpabuf_put_u8(req, version); /* Flags */ 245 return req; 246 } 247 248 249 static int eap_server_tls_process_cont(struct eap_ssl_data *data, 250 const u8 *buf, size_t len) 251 { 252 /* Process continuation of a pending message */ 253 if (len > wpabuf_tailroom(data->tls_in)) { 254 wpa_printf(MSG_DEBUG, "SSL: Fragment overflow"); 255 return -1; 256 } 257 258 wpabuf_put_data(data->tls_in, buf, len); 259 wpa_printf(MSG_DEBUG, "SSL: Received %lu bytes, waiting for %lu " 260 "bytes more", (unsigned long) len, 261 (unsigned long) wpabuf_tailroom(data->tls_in)); 262 263 return 0; 264 } 265 266 267 static int eap_server_tls_process_fragment(struct eap_ssl_data *data, 268 u8 flags, u32 message_length, 269 const u8 *buf, size_t len) 270 { 271 /* Process a fragment that is not the last one of the message */ 272 if (data->tls_in == NULL && !(flags & EAP_TLS_FLAGS_LENGTH_INCLUDED)) { 273 wpa_printf(MSG_DEBUG, "SSL: No Message Length field in a " 274 "fragmented packet"); 275 return -1; 276 } 277 278 if (data->tls_in == NULL) { 279 /* First fragment of the message */ 280 281 /* Limit length to avoid rogue peers from causing large 282 * memory allocations. */ 283 if (message_length > 65536) { 284 wpa_printf(MSG_INFO, "SSL: Too long TLS fragment (size" 285 " over 64 kB)"); 286 return -1; 287 } 288 289 if (len > message_length) { 290 wpa_printf(MSG_INFO, "SSL: Too much data (%d bytes) in " 291 "first fragment of frame (TLS Message " 292 "Length %d bytes)", 293 (int) len, (int) message_length); 294 return -1; 295 } 296 297 data->tls_in = wpabuf_alloc(message_length); 298 if (data->tls_in == NULL) { 299 wpa_printf(MSG_DEBUG, "SSL: No memory for message"); 300 return -1; 301 } 302 wpabuf_put_data(data->tls_in, buf, len); 303 wpa_printf(MSG_DEBUG, "SSL: Received %lu bytes in first " 304 "fragment, waiting for %lu bytes more", 305 (unsigned long) len, 306 (unsigned long) wpabuf_tailroom(data->tls_in)); 307 } 308 309 return 0; 310 } 311 312 313 int eap_server_tls_phase1(struct eap_sm *sm, struct eap_ssl_data *data) 314 { 315 char buf[20]; 316 317 if (data->tls_out) { 318 /* This should not happen.. */ 319 wpa_printf(MSG_INFO, "SSL: pending tls_out data when " 320 "processing new message"); 321 wpabuf_free(data->tls_out); 322 WPA_ASSERT(data->tls_out == NULL); 323 } 324 325 data->tls_out = tls_connection_server_handshake(sm->ssl_ctx, 326 data->conn, 327 data->tls_in, NULL); 328 if (data->tls_out == NULL) { 329 wpa_printf(MSG_INFO, "SSL: TLS processing failed"); 330 return -1; 331 } 332 if (tls_connection_get_failed(sm->ssl_ctx, data->conn)) { 333 /* TLS processing has failed - return error */ 334 wpa_printf(MSG_DEBUG, "SSL: Failed - tls_out available to " 335 "report error"); 336 return -1; 337 } 338 339 if (tls_get_version(sm->ssl_ctx, data->conn, buf, sizeof(buf)) == 0) { 340 wpa_printf(MSG_DEBUG, "SSL: Using TLS version %s", buf); 341 data->tls_v13 = os_strcmp(buf, "TLSv1.3") == 0; 342 } 343 344 if (!sm->serial_num && 345 tls_connection_established(sm->ssl_ctx, data->conn)) 346 sm->serial_num = tls_connection_peer_serial_num(sm->ssl_ctx, 347 data->conn); 348 349 return 0; 350 } 351 352 353 static int eap_server_tls_reassemble(struct eap_ssl_data *data, u8 flags, 354 const u8 **pos, size_t *left) 355 { 356 unsigned int tls_msg_len = 0; 357 const u8 *end = *pos + *left; 358 359 if (flags & EAP_TLS_FLAGS_LENGTH_INCLUDED) { 360 if (*left < 4) { 361 wpa_printf(MSG_INFO, "SSL: Short frame with TLS " 362 "length"); 363 return -1; 364 } 365 tls_msg_len = WPA_GET_BE32(*pos); 366 wpa_printf(MSG_DEBUG, "SSL: TLS Message Length: %d", 367 tls_msg_len); 368 *pos += 4; 369 *left -= 4; 370 371 if (*left > tls_msg_len) { 372 wpa_printf(MSG_INFO, "SSL: TLS Message Length (%d " 373 "bytes) smaller than this fragment (%d " 374 "bytes)", (int) tls_msg_len, (int) *left); 375 return -1; 376 } 377 } 378 379 wpa_printf(MSG_DEBUG, "SSL: Received packet: Flags 0x%x " 380 "Message Length %u", flags, tls_msg_len); 381 382 if (data->state == WAIT_FRAG_ACK) { 383 if (*left != 0) { 384 wpa_printf(MSG_DEBUG, "SSL: Unexpected payload in " 385 "WAIT_FRAG_ACK state"); 386 return -1; 387 } 388 wpa_printf(MSG_DEBUG, "SSL: Fragment acknowledged"); 389 return 1; 390 } 391 392 if (data->tls_in && 393 eap_server_tls_process_cont(data, *pos, end - *pos) < 0) 394 return -1; 395 396 if (flags & EAP_TLS_FLAGS_MORE_FRAGMENTS) { 397 if (eap_server_tls_process_fragment(data, flags, tls_msg_len, 398 *pos, end - *pos) < 0) 399 return -1; 400 401 data->state = FRAG_ACK; 402 return 1; 403 } 404 405 if (data->state == FRAG_ACK) { 406 wpa_printf(MSG_DEBUG, "SSL: All fragments received"); 407 data->state = MSG; 408 } 409 410 if (data->tls_in == NULL) { 411 /* Wrap unfragmented messages as wpabuf without extra copy */ 412 wpabuf_set(&data->tmpbuf, *pos, end - *pos); 413 data->tls_in = &data->tmpbuf; 414 } 415 416 return 0; 417 } 418 419 420 static void eap_server_tls_free_in_buf(struct eap_ssl_data *data) 421 { 422 if (data->tls_in != &data->tmpbuf) 423 wpabuf_free(data->tls_in); 424 data->tls_in = NULL; 425 } 426 427 428 struct wpabuf * eap_server_tls_encrypt(struct eap_sm *sm, 429 struct eap_ssl_data *data, 430 const struct wpabuf *plain) 431 { 432 struct wpabuf *buf; 433 434 buf = tls_connection_encrypt(sm->ssl_ctx, data->conn, 435 plain); 436 if (buf == NULL) { 437 wpa_printf(MSG_INFO, "SSL: Failed to encrypt Phase 2 data"); 438 return NULL; 439 } 440 441 return buf; 442 } 443 444 445 int eap_server_tls_process(struct eap_sm *sm, struct eap_ssl_data *data, 446 struct wpabuf *respData, void *priv, int eap_type, 447 int (*proc_version)(struct eap_sm *sm, void *priv, 448 int peer_version), 449 void (*proc_msg)(struct eap_sm *sm, void *priv, 450 const struct wpabuf *respData)) 451 { 452 const u8 *pos; 453 u8 flags; 454 size_t left; 455 int ret, res = 0; 456 457 if (eap_type == EAP_UNAUTH_TLS_TYPE) 458 pos = eap_hdr_validate(EAP_VENDOR_UNAUTH_TLS, 459 EAP_VENDOR_TYPE_UNAUTH_TLS, respData, 460 &left); 461 else if (eap_type == EAP_WFA_UNAUTH_TLS_TYPE) 462 pos = eap_hdr_validate(EAP_VENDOR_WFA_NEW, 463 EAP_VENDOR_WFA_UNAUTH_TLS, respData, 464 &left); 465 else 466 pos = eap_hdr_validate(EAP_VENDOR_IETF, eap_type, respData, 467 &left); 468 if (pos == NULL || left < 1) 469 return 0; /* Should not happen - frame already validated */ 470 flags = *pos++; 471 left--; 472 wpa_printf(MSG_DEBUG, "SSL: Received packet(len=%lu) - Flags 0x%02x", 473 (unsigned long) wpabuf_len(respData), flags); 474 475 if (proc_version && 476 proc_version(sm, priv, flags & EAP_TLS_VERSION_MASK) < 0) 477 return -1; 478 479 ret = eap_server_tls_reassemble(data, flags, &pos, &left); 480 if (ret < 0) { 481 res = -1; 482 goto done; 483 } else if (ret == 1) 484 return 0; 485 486 if (proc_msg) 487 proc_msg(sm, priv, respData); 488 489 if (tls_connection_get_write_alerts(sm->ssl_ctx, data->conn) > 1) { 490 wpa_printf(MSG_INFO, "SSL: Locally detected fatal error in " 491 "TLS processing"); 492 res = -1; 493 } 494 495 done: 496 eap_server_tls_free_in_buf(data); 497 498 return res; 499 } 500