statem_dtls.c revision 1.1.1.1.2.3
1 /* 2 * Copyright 2005-2018 The OpenSSL Project Authors. All Rights Reserved. 3 * 4 * Licensed under the OpenSSL license (the "License"). You may not use 5 * this file except in compliance with the License. You can obtain a copy 6 * in the file LICENSE in the source distribution or at 7 * https://www.openssl.org/source/license.html 8 */ 9 10 #include <limits.h> 11 #include <string.h> 12 #include <stdio.h> 13 #include "../ssl_locl.h" 14 #include "statem_locl.h" 15 #include "internal/cryptlib.h" 16 #include <openssl/buffer.h> 17 #include <openssl/objects.h> 18 #include <openssl/evp.h> 19 #include <openssl/x509.h> 20 21 #define RSMBLY_BITMASK_SIZE(msg_len) (((msg_len) + 7) / 8) 22 23 #define RSMBLY_BITMASK_MARK(bitmask, start, end) { \ 24 if ((end) - (start) <= 8) { \ 25 long ii; \ 26 for (ii = (start); ii < (end); ii++) bitmask[((ii) >> 3)] |= (1 << ((ii) & 7)); \ 27 } else { \ 28 long ii; \ 29 bitmask[((start) >> 3)] |= bitmask_start_values[((start) & 7)]; \ 30 for (ii = (((start) >> 3) + 1); ii < ((((end) - 1)) >> 3); ii++) bitmask[ii] = 0xff; \ 31 bitmask[(((end) - 1) >> 3)] |= bitmask_end_values[((end) & 7)]; \ 32 } } 33 34 #define RSMBLY_BITMASK_IS_COMPLETE(bitmask, msg_len, is_complete) { \ 35 long ii; \ 36 is_complete = 1; \ 37 if (bitmask[(((msg_len) - 1) >> 3)] != bitmask_end_values[((msg_len) & 7)]) is_complete = 0; \ 38 if (is_complete) for (ii = (((msg_len) - 1) >> 3) - 1; ii >= 0 ; ii--) \ 39 if (bitmask[ii] != 0xff) { is_complete = 0; break; } } 40 41 static unsigned char bitmask_start_values[] = 42 { 0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80 }; 43 static unsigned char bitmask_end_values[] = 44 { 0xff, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f }; 45 46 static void dtls1_fix_message_header(SSL *s, size_t frag_off, 47 size_t frag_len); 48 static unsigned char *dtls1_write_message_header(SSL *s, unsigned char *p); 49 static void dtls1_set_message_header_int(SSL *s, unsigned char mt, 50 size_t len, 51 unsigned short seq_num, 52 size_t frag_off, 53 size_t frag_len); 54 static int dtls_get_reassembled_message(SSL *s, int *errtype, size_t *len); 55 56 static hm_fragment *dtls1_hm_fragment_new(size_t frag_len, int reassembly) 57 { 58 hm_fragment *frag = NULL; 59 unsigned char *buf = NULL; 60 unsigned char *bitmask = NULL; 61 62 if ((frag = OPENSSL_malloc(sizeof(*frag))) == NULL) { 63 SSLerr(SSL_F_DTLS1_HM_FRAGMENT_NEW, ERR_R_MALLOC_FAILURE); 64 return NULL; 65 } 66 67 if (frag_len) { 68 if ((buf = OPENSSL_malloc(frag_len)) == NULL) { 69 SSLerr(SSL_F_DTLS1_HM_FRAGMENT_NEW, ERR_R_MALLOC_FAILURE); 70 OPENSSL_free(frag); 71 return NULL; 72 } 73 } 74 75 /* zero length fragment gets zero frag->fragment */ 76 frag->fragment = buf; 77 78 /* Initialize reassembly bitmask if necessary */ 79 if (reassembly) { 80 bitmask = OPENSSL_zalloc(RSMBLY_BITMASK_SIZE(frag_len)); 81 if (bitmask == NULL) { 82 SSLerr(SSL_F_DTLS1_HM_FRAGMENT_NEW, ERR_R_MALLOC_FAILURE); 83 OPENSSL_free(buf); 84 OPENSSL_free(frag); 85 return NULL; 86 } 87 } 88 89 frag->reassembly = bitmask; 90 91 return frag; 92 } 93 94 void dtls1_hm_fragment_free(hm_fragment *frag) 95 { 96 if (!frag) 97 return; 98 if (frag->msg_header.is_ccs) { 99 EVP_CIPHER_CTX_free(frag->msg_header. 100 saved_retransmit_state.enc_write_ctx); 101 EVP_MD_CTX_free(frag->msg_header.saved_retransmit_state.write_hash); 102 } 103 OPENSSL_free(frag->fragment); 104 OPENSSL_free(frag->reassembly); 105 OPENSSL_free(frag); 106 } 107 108 /* 109 * send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or 110 * SSL3_RT_CHANGE_CIPHER_SPEC) 111 */ 112 int dtls1_do_write(SSL *s, int type) 113 { 114 int ret; 115 size_t written; 116 size_t curr_mtu; 117 int retry = 1; 118 size_t len, frag_off, mac_size, blocksize, used_len; 119 120 if (!dtls1_query_mtu(s)) 121 return -1; 122 123 if (s->d1->mtu < dtls1_min_mtu(s)) 124 /* should have something reasonable now */ 125 return -1; 126 127 if (s->init_off == 0 && type == SSL3_RT_HANDSHAKE) { 128 if (!ossl_assert(s->init_num == 129 s->d1->w_msg_hdr.msg_len + DTLS1_HM_HEADER_LENGTH)) 130 return -1; 131 } 132 133 if (s->write_hash) { 134 if (s->enc_write_ctx 135 && (EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(s->enc_write_ctx)) & 136 EVP_CIPH_FLAG_AEAD_CIPHER) != 0) 137 mac_size = 0; 138 else 139 mac_size = EVP_MD_CTX_size(s->write_hash); 140 } else 141 mac_size = 0; 142 143 if (s->enc_write_ctx && 144 (EVP_CIPHER_CTX_mode(s->enc_write_ctx) == EVP_CIPH_CBC_MODE)) 145 blocksize = 2 * EVP_CIPHER_CTX_block_size(s->enc_write_ctx); 146 else 147 blocksize = 0; 148 149 frag_off = 0; 150 s->rwstate = SSL_NOTHING; 151 152 /* s->init_num shouldn't ever be < 0...but just in case */ 153 while (s->init_num > 0) { 154 if (type == SSL3_RT_HANDSHAKE && s->init_off != 0) { 155 /* We must be writing a fragment other than the first one */ 156 157 if (frag_off > 0) { 158 /* This is the first attempt at writing out this fragment */ 159 160 if (s->init_off <= DTLS1_HM_HEADER_LENGTH) { 161 /* 162 * Each fragment that was already sent must at least have 163 * contained the message header plus one other byte. 164 * Therefore |init_off| must have progressed by at least 165 * |DTLS1_HM_HEADER_LENGTH + 1| bytes. If not something went 166 * wrong. 167 */ 168 return -1; 169 } 170 171 /* 172 * Adjust |init_off| and |init_num| to allow room for a new 173 * message header for this fragment. 174 */ 175 s->init_off -= DTLS1_HM_HEADER_LENGTH; 176 s->init_num += DTLS1_HM_HEADER_LENGTH; 177 } else { 178 /* 179 * We must have been called again after a retry so use the 180 * fragment offset from our last attempt. We do not need 181 * to adjust |init_off| and |init_num| as above, because 182 * that should already have been done before the retry. 183 */ 184 frag_off = s->d1->w_msg_hdr.frag_off; 185 } 186 } 187 188 used_len = BIO_wpending(s->wbio) + DTLS1_RT_HEADER_LENGTH 189 + mac_size + blocksize; 190 if (s->d1->mtu > used_len) 191 curr_mtu = s->d1->mtu - used_len; 192 else 193 curr_mtu = 0; 194 195 if (curr_mtu <= DTLS1_HM_HEADER_LENGTH) { 196 /* 197 * grr.. we could get an error if MTU picked was wrong 198 */ 199 ret = BIO_flush(s->wbio); 200 if (ret <= 0) { 201 s->rwstate = SSL_WRITING; 202 return ret; 203 } 204 used_len = DTLS1_RT_HEADER_LENGTH + mac_size + blocksize; 205 if (s->d1->mtu > used_len + DTLS1_HM_HEADER_LENGTH) { 206 curr_mtu = s->d1->mtu - used_len; 207 } else { 208 /* Shouldn't happen */ 209 return -1; 210 } 211 } 212 213 /* 214 * We just checked that s->init_num > 0 so this cast should be safe 215 */ 216 if (((unsigned int)s->init_num) > curr_mtu) 217 len = curr_mtu; 218 else 219 len = s->init_num; 220 221 if (len > s->max_send_fragment) 222 len = s->max_send_fragment; 223 224 /* 225 * XDTLS: this function is too long. split out the CCS part 226 */ 227 if (type == SSL3_RT_HANDSHAKE) { 228 if (len < DTLS1_HM_HEADER_LENGTH) { 229 /* 230 * len is so small that we really can't do anything sensible 231 * so fail 232 */ 233 return -1; 234 } 235 dtls1_fix_message_header(s, frag_off, len - DTLS1_HM_HEADER_LENGTH); 236 237 dtls1_write_message_header(s, 238 (unsigned char *)&s->init_buf-> 239 data[s->init_off]); 240 } 241 242 ret = dtls1_write_bytes(s, type, &s->init_buf->data[s->init_off], len, 243 &written); 244 if (ret < 0) { 245 /* 246 * might need to update MTU here, but we don't know which 247 * previous packet caused the failure -- so can't really 248 * retransmit anything. continue as if everything is fine and 249 * wait for an alert to handle the retransmit 250 */ 251 if (retry && BIO_ctrl(SSL_get_wbio(s), 252 BIO_CTRL_DGRAM_MTU_EXCEEDED, 0, NULL) > 0) { 253 if (!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) { 254 if (!dtls1_query_mtu(s)) 255 return -1; 256 /* Have one more go */ 257 retry = 0; 258 } else 259 return -1; 260 } else { 261 return -1; 262 } 263 } else { 264 265 /* 266 * bad if this assert fails, only part of the handshake message 267 * got sent. but why would this happen? 268 */ 269 if (!ossl_assert(len == written)) 270 return -1; 271 272 if (type == SSL3_RT_HANDSHAKE && !s->d1->retransmitting) { 273 /* 274 * should not be done for 'Hello Request's, but in that case 275 * we'll ignore the result anyway 276 */ 277 unsigned char *p = 278 (unsigned char *)&s->init_buf->data[s->init_off]; 279 const struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr; 280 size_t xlen; 281 282 if (frag_off == 0 && s->version != DTLS1_BAD_VER) { 283 /* 284 * reconstruct message header is if it is being sent in 285 * single fragment 286 */ 287 *p++ = msg_hdr->type; 288 l2n3(msg_hdr->msg_len, p); 289 s2n(msg_hdr->seq, p); 290 l2n3(0, p); 291 l2n3(msg_hdr->msg_len, p); 292 p -= DTLS1_HM_HEADER_LENGTH; 293 xlen = written; 294 } else { 295 p += DTLS1_HM_HEADER_LENGTH; 296 xlen = written - DTLS1_HM_HEADER_LENGTH; 297 } 298 299 if (!ssl3_finish_mac(s, p, xlen)) 300 return -1; 301 } 302 303 if (written == s->init_num) { 304 if (s->msg_callback) 305 s->msg_callback(1, s->version, type, s->init_buf->data, 306 (size_t)(s->init_off + s->init_num), s, 307 s->msg_callback_arg); 308 309 s->init_off = 0; /* done writing this message */ 310 s->init_num = 0; 311 312 return 1; 313 } 314 s->init_off += written; 315 s->init_num -= written; 316 written -= DTLS1_HM_HEADER_LENGTH; 317 frag_off += written; 318 319 /* 320 * We save the fragment offset for the next fragment so we have it 321 * available in case of an IO retry. We don't know the length of the 322 * next fragment yet so just set that to 0 for now. It will be 323 * updated again later. 324 */ 325 dtls1_fix_message_header(s, frag_off, 0); 326 } 327 } 328 return 0; 329 } 330 331 int dtls_get_message(SSL *s, int *mt, size_t *len) 332 { 333 struct hm_header_st *msg_hdr; 334 unsigned char *p; 335 size_t msg_len; 336 size_t tmplen; 337 int errtype; 338 339 msg_hdr = &s->d1->r_msg_hdr; 340 memset(msg_hdr, 0, sizeof(*msg_hdr)); 341 342 again: 343 if (!dtls_get_reassembled_message(s, &errtype, &tmplen)) { 344 if (errtype == DTLS1_HM_BAD_FRAGMENT 345 || errtype == DTLS1_HM_FRAGMENT_RETRY) { 346 /* bad fragment received */ 347 goto again; 348 } 349 return 0; 350 } 351 352 *mt = s->s3->tmp.message_type; 353 354 p = (unsigned char *)s->init_buf->data; 355 *len = s->init_num; 356 357 if (*mt == SSL3_MT_CHANGE_CIPHER_SPEC) { 358 if (s->msg_callback) { 359 s->msg_callback(0, s->version, SSL3_RT_CHANGE_CIPHER_SPEC, 360 p, 1, s, s->msg_callback_arg); 361 } 362 /* 363 * This isn't a real handshake message so skip the processing below. 364 */ 365 return 1; 366 } 367 368 msg_len = msg_hdr->msg_len; 369 370 /* reconstruct message header */ 371 *(p++) = msg_hdr->type; 372 l2n3(msg_len, p); 373 s2n(msg_hdr->seq, p); 374 l2n3(0, p); 375 l2n3(msg_len, p); 376 if (s->version != DTLS1_BAD_VER) { 377 p -= DTLS1_HM_HEADER_LENGTH; 378 msg_len += DTLS1_HM_HEADER_LENGTH; 379 } 380 381 /* 382 * If receiving Finished, record MAC of prior handshake messages for 383 * Finished verification. 384 */ 385 if (*mt == SSL3_MT_FINISHED && !ssl3_take_mac(s)) { 386 /* SSLfatal() already called */ 387 return 0; 388 } 389 390 if (!ssl3_finish_mac(s, p, msg_len)) 391 return 0; 392 if (s->msg_callback) 393 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, 394 p, msg_len, s, s->msg_callback_arg); 395 396 memset(msg_hdr, 0, sizeof(*msg_hdr)); 397 398 s->d1->handshake_read_seq++; 399 400 s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH; 401 402 return 1; 403 } 404 405 /* 406 * dtls1_max_handshake_message_len returns the maximum number of bytes 407 * permitted in a DTLS handshake message for |s|. The minimum is 16KB, but 408 * may be greater if the maximum certificate list size requires it. 409 */ 410 static size_t dtls1_max_handshake_message_len(const SSL *s) 411 { 412 size_t max_len = DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH; 413 if (max_len < s->max_cert_list) 414 return s->max_cert_list; 415 return max_len; 416 } 417 418 static int dtls1_preprocess_fragment(SSL *s, struct hm_header_st *msg_hdr) 419 { 420 size_t frag_off, frag_len, msg_len; 421 422 msg_len = msg_hdr->msg_len; 423 frag_off = msg_hdr->frag_off; 424 frag_len = msg_hdr->frag_len; 425 426 /* sanity checking */ 427 if ((frag_off + frag_len) > msg_len 428 || msg_len > dtls1_max_handshake_message_len(s)) { 429 SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_DTLS1_PREPROCESS_FRAGMENT, 430 SSL_R_EXCESSIVE_MESSAGE_SIZE); 431 return 0; 432 } 433 434 if (s->d1->r_msg_hdr.frag_off == 0) { /* first fragment */ 435 /* 436 * msg_len is limited to 2^24, but is effectively checked against 437 * dtls_max_handshake_message_len(s) above 438 */ 439 if (!BUF_MEM_grow_clean(s->init_buf, msg_len + DTLS1_HM_HEADER_LENGTH)) { 440 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DTLS1_PREPROCESS_FRAGMENT, 441 ERR_R_BUF_LIB); 442 return 0; 443 } 444 445 s->s3->tmp.message_size = msg_len; 446 s->d1->r_msg_hdr.msg_len = msg_len; 447 s->s3->tmp.message_type = msg_hdr->type; 448 s->d1->r_msg_hdr.type = msg_hdr->type; 449 s->d1->r_msg_hdr.seq = msg_hdr->seq; 450 } else if (msg_len != s->d1->r_msg_hdr.msg_len) { 451 /* 452 * They must be playing with us! BTW, failure to enforce upper limit 453 * would open possibility for buffer overrun. 454 */ 455 SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_DTLS1_PREPROCESS_FRAGMENT, 456 SSL_R_EXCESSIVE_MESSAGE_SIZE); 457 return 0; 458 } 459 460 return 1; 461 } 462 463 /* 464 * Returns 1 if there is a buffered fragment available, 0 if not, or -1 on a 465 * fatal error. 466 */ 467 static int dtls1_retrieve_buffered_fragment(SSL *s, size_t *len) 468 { 469 /*- 470 * (0) check whether the desired fragment is available 471 * if so: 472 * (1) copy over the fragment to s->init_buf->data[] 473 * (2) update s->init_num 474 */ 475 pitem *item; 476 hm_fragment *frag; 477 int ret; 478 479 do { 480 item = pqueue_peek(s->d1->buffered_messages); 481 if (item == NULL) 482 return 0; 483 484 frag = (hm_fragment *)item->data; 485 486 if (frag->msg_header.seq < s->d1->handshake_read_seq) { 487 /* This is a stale message that has been buffered so clear it */ 488 pqueue_pop(s->d1->buffered_messages); 489 dtls1_hm_fragment_free(frag); 490 pitem_free(item); 491 item = NULL; 492 frag = NULL; 493 } 494 } while (item == NULL); 495 496 /* Don't return if reassembly still in progress */ 497 if (frag->reassembly != NULL) 498 return 0; 499 500 if (s->d1->handshake_read_seq == frag->msg_header.seq) { 501 size_t frag_len = frag->msg_header.frag_len; 502 pqueue_pop(s->d1->buffered_messages); 503 504 /* Calls SSLfatal() as required */ 505 ret = dtls1_preprocess_fragment(s, &frag->msg_header); 506 507 if (ret && frag->msg_header.frag_len > 0) { 508 unsigned char *p = 509 (unsigned char *)s->init_buf->data + DTLS1_HM_HEADER_LENGTH; 510 memcpy(&p[frag->msg_header.frag_off], frag->fragment, 511 frag->msg_header.frag_len); 512 } 513 514 dtls1_hm_fragment_free(frag); 515 pitem_free(item); 516 517 if (ret) { 518 *len = frag_len; 519 return 1; 520 } 521 522 /* Fatal error */ 523 s->init_num = 0; 524 return -1; 525 } else { 526 return 0; 527 } 528 } 529 530 static int 531 dtls1_reassemble_fragment(SSL *s, const struct hm_header_st *msg_hdr) 532 { 533 hm_fragment *frag = NULL; 534 pitem *item = NULL; 535 int i = -1, is_complete; 536 unsigned char seq64be[8]; 537 size_t frag_len = msg_hdr->frag_len; 538 size_t readbytes; 539 540 if ((msg_hdr->frag_off + frag_len) > msg_hdr->msg_len || 541 msg_hdr->msg_len > dtls1_max_handshake_message_len(s)) 542 goto err; 543 544 if (frag_len == 0) { 545 return DTLS1_HM_FRAGMENT_RETRY; 546 } 547 548 /* Try to find item in queue */ 549 memset(seq64be, 0, sizeof(seq64be)); 550 seq64be[6] = (unsigned char)(msg_hdr->seq >> 8); 551 seq64be[7] = (unsigned char)msg_hdr->seq; 552 item = pqueue_find(s->d1->buffered_messages, seq64be); 553 554 if (item == NULL) { 555 frag = dtls1_hm_fragment_new(msg_hdr->msg_len, 1); 556 if (frag == NULL) 557 goto err; 558 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr)); 559 frag->msg_header.frag_len = frag->msg_header.msg_len; 560 frag->msg_header.frag_off = 0; 561 } else { 562 frag = (hm_fragment *)item->data; 563 if (frag->msg_header.msg_len != msg_hdr->msg_len) { 564 item = NULL; 565 frag = NULL; 566 goto err; 567 } 568 } 569 570 /* 571 * If message is already reassembled, this must be a retransmit and can 572 * be dropped. In this case item != NULL and so frag does not need to be 573 * freed. 574 */ 575 if (frag->reassembly == NULL) { 576 unsigned char devnull[256]; 577 578 while (frag_len) { 579 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, NULL, 580 devnull, 581 frag_len > 582 sizeof(devnull) ? sizeof(devnull) : 583 frag_len, 0, &readbytes); 584 if (i <= 0) 585 goto err; 586 frag_len -= readbytes; 587 } 588 return DTLS1_HM_FRAGMENT_RETRY; 589 } 590 591 /* read the body of the fragment (header has already been read */ 592 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, NULL, 593 frag->fragment + msg_hdr->frag_off, 594 frag_len, 0, &readbytes); 595 if (i <= 0 || readbytes != frag_len) 596 i = -1; 597 if (i <= 0) 598 goto err; 599 600 RSMBLY_BITMASK_MARK(frag->reassembly, (long)msg_hdr->frag_off, 601 (long)(msg_hdr->frag_off + frag_len)); 602 603 if (!ossl_assert(msg_hdr->msg_len > 0)) 604 goto err; 605 RSMBLY_BITMASK_IS_COMPLETE(frag->reassembly, (long)msg_hdr->msg_len, 606 is_complete); 607 608 if (is_complete) { 609 OPENSSL_free(frag->reassembly); 610 frag->reassembly = NULL; 611 } 612 613 if (item == NULL) { 614 item = pitem_new(seq64be, frag); 615 if (item == NULL) { 616 i = -1; 617 goto err; 618 } 619 620 item = pqueue_insert(s->d1->buffered_messages, item); 621 /* 622 * pqueue_insert fails iff a duplicate item is inserted. However, 623 * |item| cannot be a duplicate. If it were, |pqueue_find|, above, 624 * would have returned it and control would never have reached this 625 * branch. 626 */ 627 if (!ossl_assert(item != NULL)) 628 goto err; 629 } 630 631 return DTLS1_HM_FRAGMENT_RETRY; 632 633 err: 634 if (item == NULL) 635 dtls1_hm_fragment_free(frag); 636 return -1; 637 } 638 639 static int 640 dtls1_process_out_of_seq_message(SSL *s, const struct hm_header_st *msg_hdr) 641 { 642 int i = -1; 643 hm_fragment *frag = NULL; 644 pitem *item = NULL; 645 unsigned char seq64be[8]; 646 size_t frag_len = msg_hdr->frag_len; 647 size_t readbytes; 648 649 if ((msg_hdr->frag_off + frag_len) > msg_hdr->msg_len) 650 goto err; 651 652 /* Try to find item in queue, to prevent duplicate entries */ 653 memset(seq64be, 0, sizeof(seq64be)); 654 seq64be[6] = (unsigned char)(msg_hdr->seq >> 8); 655 seq64be[7] = (unsigned char)msg_hdr->seq; 656 item = pqueue_find(s->d1->buffered_messages, seq64be); 657 658 /* 659 * If we already have an entry and this one is a fragment, don't discard 660 * it and rather try to reassemble it. 661 */ 662 if (item != NULL && frag_len != msg_hdr->msg_len) 663 item = NULL; 664 665 /* 666 * Discard the message if sequence number was already there, is too far 667 * in the future, already in the queue or if we received a FINISHED 668 * before the SERVER_HELLO, which then must be a stale retransmit. 669 */ 670 if (msg_hdr->seq <= s->d1->handshake_read_seq || 671 msg_hdr->seq > s->d1->handshake_read_seq + 10 || item != NULL || 672 (s->d1->handshake_read_seq == 0 && msg_hdr->type == SSL3_MT_FINISHED)) { 673 unsigned char devnull[256]; 674 675 while (frag_len) { 676 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, NULL, 677 devnull, 678 frag_len > 679 sizeof(devnull) ? sizeof(devnull) : 680 frag_len, 0, &readbytes); 681 if (i <= 0) 682 goto err; 683 frag_len -= readbytes; 684 } 685 } else { 686 if (frag_len != msg_hdr->msg_len) { 687 return dtls1_reassemble_fragment(s, msg_hdr); 688 } 689 690 if (frag_len > dtls1_max_handshake_message_len(s)) 691 goto err; 692 693 frag = dtls1_hm_fragment_new(frag_len, 0); 694 if (frag == NULL) 695 goto err; 696 697 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr)); 698 699 if (frag_len) { 700 /* 701 * read the body of the fragment (header has already been read 702 */ 703 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, NULL, 704 frag->fragment, frag_len, 0, 705 &readbytes); 706 if (i<=0 || readbytes != frag_len) 707 i = -1; 708 if (i <= 0) 709 goto err; 710 } 711 712 item = pitem_new(seq64be, frag); 713 if (item == NULL) 714 goto err; 715 716 item = pqueue_insert(s->d1->buffered_messages, item); 717 /* 718 * pqueue_insert fails iff a duplicate item is inserted. However, 719 * |item| cannot be a duplicate. If it were, |pqueue_find|, above, 720 * would have returned it. Then, either |frag_len| != 721 * |msg_hdr->msg_len| in which case |item| is set to NULL and it will 722 * have been processed with |dtls1_reassemble_fragment|, above, or 723 * the record will have been discarded. 724 */ 725 if (!ossl_assert(item != NULL)) 726 goto err; 727 } 728 729 return DTLS1_HM_FRAGMENT_RETRY; 730 731 err: 732 if (item == NULL) 733 dtls1_hm_fragment_free(frag); 734 return 0; 735 } 736 737 static int dtls_get_reassembled_message(SSL *s, int *errtype, size_t *len) 738 { 739 unsigned char wire[DTLS1_HM_HEADER_LENGTH]; 740 size_t mlen, frag_off, frag_len; 741 int i, ret, recvd_type; 742 struct hm_header_st msg_hdr; 743 size_t readbytes; 744 745 *errtype = 0; 746 747 redo: 748 /* see if we have the required fragment already */ 749 ret = dtls1_retrieve_buffered_fragment(s, &frag_len); 750 if (ret < 0) { 751 /* SSLfatal() already called */ 752 return 0; 753 } 754 if (ret > 0) { 755 s->init_num = frag_len; 756 *len = frag_len; 757 return 1; 758 } 759 760 /* read handshake message header */ 761 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, &recvd_type, wire, 762 DTLS1_HM_HEADER_LENGTH, 0, &readbytes); 763 if (i <= 0) { /* nbio, or an error */ 764 s->rwstate = SSL_READING; 765 *len = 0; 766 return 0; 767 } 768 if (recvd_type == SSL3_RT_CHANGE_CIPHER_SPEC) { 769 if (wire[0] != SSL3_MT_CCS) { 770 SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, 771 SSL_F_DTLS_GET_REASSEMBLED_MESSAGE, 772 SSL_R_BAD_CHANGE_CIPHER_SPEC); 773 goto f_err; 774 } 775 776 memcpy(s->init_buf->data, wire, readbytes); 777 s->init_num = readbytes - 1; 778 s->init_msg = s->init_buf->data + 1; 779 s->s3->tmp.message_type = SSL3_MT_CHANGE_CIPHER_SPEC; 780 s->s3->tmp.message_size = readbytes - 1; 781 *len = readbytes - 1; 782 return 1; 783 } 784 785 /* Handshake fails if message header is incomplete */ 786 if (readbytes != DTLS1_HM_HEADER_LENGTH) { 787 SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, 788 SSL_F_DTLS_GET_REASSEMBLED_MESSAGE, SSL_R_UNEXPECTED_MESSAGE); 789 goto f_err; 790 } 791 792 /* parse the message fragment header */ 793 dtls1_get_message_header(wire, &msg_hdr); 794 795 mlen = msg_hdr.msg_len; 796 frag_off = msg_hdr.frag_off; 797 frag_len = msg_hdr.frag_len; 798 799 /* 800 * We must have at least frag_len bytes left in the record to be read. 801 * Fragments must not span records. 802 */ 803 if (frag_len > RECORD_LAYER_get_rrec_length(&s->rlayer)) { 804 SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, 805 SSL_F_DTLS_GET_REASSEMBLED_MESSAGE, SSL_R_BAD_LENGTH); 806 goto f_err; 807 } 808 809 /* 810 * if this is a future (or stale) message it gets buffered 811 * (or dropped)--no further processing at this time 812 * While listening, we accept seq 1 (ClientHello with cookie) 813 * although we're still expecting seq 0 (ClientHello) 814 */ 815 if (msg_hdr.seq != s->d1->handshake_read_seq) { 816 *errtype = dtls1_process_out_of_seq_message(s, &msg_hdr); 817 return 0; 818 } 819 820 if (frag_len && frag_len < mlen) { 821 *errtype = dtls1_reassemble_fragment(s, &msg_hdr); 822 return 0; 823 } 824 825 if (!s->server 826 && s->d1->r_msg_hdr.frag_off == 0 827 && s->statem.hand_state != TLS_ST_OK 828 && wire[0] == SSL3_MT_HELLO_REQUEST) { 829 /* 830 * The server may always send 'Hello Request' messages -- we are 831 * doing a handshake anyway now, so ignore them if their format is 832 * correct. Does not count for 'Finished' MAC. 833 */ 834 if (wire[1] == 0 && wire[2] == 0 && wire[3] == 0) { 835 if (s->msg_callback) 836 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, 837 wire, DTLS1_HM_HEADER_LENGTH, s, 838 s->msg_callback_arg); 839 840 s->init_num = 0; 841 goto redo; 842 } else { /* Incorrectly formatted Hello request */ 843 844 SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, 845 SSL_F_DTLS_GET_REASSEMBLED_MESSAGE, 846 SSL_R_UNEXPECTED_MESSAGE); 847 goto f_err; 848 } 849 } 850 851 if (!dtls1_preprocess_fragment(s, &msg_hdr)) { 852 /* SSLfatal() already called */ 853 goto f_err; 854 } 855 856 if (frag_len > 0) { 857 unsigned char *p = 858 (unsigned char *)s->init_buf->data + DTLS1_HM_HEADER_LENGTH; 859 860 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, NULL, 861 &p[frag_off], frag_len, 0, &readbytes); 862 863 /* 864 * This shouldn't ever fail due to NBIO because we already checked 865 * that we have enough data in the record 866 */ 867 if (i <= 0) { 868 s->rwstate = SSL_READING; 869 *len = 0; 870 return 0; 871 } 872 } else { 873 readbytes = 0; 874 } 875 876 /* 877 * XDTLS: an incorrectly formatted fragment should cause the handshake 878 * to fail 879 */ 880 if (readbytes != frag_len) { 881 SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, 882 SSL_F_DTLS_GET_REASSEMBLED_MESSAGE, SSL_R_BAD_LENGTH); 883 goto f_err; 884 } 885 886 /* 887 * Note that s->init_num is *not* used as current offset in 888 * s->init_buf->data, but as a counter summing up fragments' lengths: as 889 * soon as they sum up to handshake packet length, we assume we have got 890 * all the fragments. 891 */ 892 *len = s->init_num = frag_len; 893 return 1; 894 895 f_err: 896 s->init_num = 0; 897 *len = 0; 898 return 0; 899 } 900 901 /*- 902 * for these 2 messages, we need to 903 * ssl->enc_read_ctx re-init 904 * ssl->rlayer.read_sequence zero 905 * ssl->s3->read_mac_secret re-init 906 * ssl->session->read_sym_enc assign 907 * ssl->session->read_compression assign 908 * ssl->session->read_hash assign 909 */ 910 int dtls_construct_change_cipher_spec(SSL *s, WPACKET *pkt) 911 { 912 if (s->version == DTLS1_BAD_VER) { 913 s->d1->next_handshake_write_seq++; 914 915 if (!WPACKET_put_bytes_u16(pkt, s->d1->handshake_write_seq)) { 916 SSLfatal(s, SSL_AD_INTERNAL_ERROR, 917 SSL_F_DTLS_CONSTRUCT_CHANGE_CIPHER_SPEC, 918 ERR_R_INTERNAL_ERROR); 919 return 0; 920 } 921 } 922 923 return 1; 924 } 925 926 #ifndef OPENSSL_NO_SCTP 927 /* 928 * Wait for a dry event. Should only be called at a point in the handshake 929 * where we are not expecting any data from the peer except an alert. 930 */ 931 WORK_STATE dtls_wait_for_dry(SSL *s) 932 { 933 int ret, errtype; 934 size_t len; 935 936 /* read app data until dry event */ 937 ret = BIO_dgram_sctp_wait_for_dry(SSL_get_wbio(s)); 938 if (ret < 0) { 939 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DTLS_WAIT_FOR_DRY, 940 ERR_R_INTERNAL_ERROR); 941 return WORK_ERROR; 942 } 943 944 if (ret == 0) { 945 /* 946 * We're not expecting any more messages from the peer at this point - 947 * but we could get an alert. If an alert is waiting then we will never 948 * return successfully. Therefore we attempt to read a message. This 949 * should never succeed but will process any waiting alerts. 950 */ 951 if (dtls_get_reassembled_message(s, &errtype, &len)) { 952 /* The call succeeded! This should never happen */ 953 SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, SSL_F_DTLS_WAIT_FOR_DRY, 954 SSL_R_UNEXPECTED_MESSAGE); 955 return WORK_ERROR; 956 } 957 958 s->s3->in_read_app_data = 2; 959 s->rwstate = SSL_READING; 960 BIO_clear_retry_flags(SSL_get_rbio(s)); 961 BIO_set_retry_read(SSL_get_rbio(s)); 962 return WORK_MORE_A; 963 } 964 return WORK_FINISHED_CONTINUE; 965 } 966 #endif 967 968 int dtls1_read_failed(SSL *s, int code) 969 { 970 if (code > 0) { 971 SSLfatal(s, SSL_AD_INTERNAL_ERROR, 972 SSL_F_DTLS1_READ_FAILED, ERR_R_INTERNAL_ERROR); 973 return 0; 974 } 975 976 if (!dtls1_is_timer_expired(s) || ossl_statem_in_error(s)) { 977 /* 978 * not a timeout, none of our business, let higher layers handle 979 * this. in fact it's probably an error 980 */ 981 return code; 982 } 983 /* done, no need to send a retransmit */ 984 if (!SSL_in_init(s)) 985 { 986 BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ); 987 return code; 988 } 989 990 return dtls1_handle_timeout(s); 991 } 992 993 int dtls1_get_queue_priority(unsigned short seq, int is_ccs) 994 { 995 /* 996 * The index of the retransmission queue actually is the message sequence 997 * number, since the queue only contains messages of a single handshake. 998 * However, the ChangeCipherSpec has no message sequence number and so 999 * using only the sequence will result in the CCS and Finished having the 1000 * same index. To prevent this, the sequence number is multiplied by 2. 1001 * In case of a CCS 1 is subtracted. This does not only differ CSS and 1002 * Finished, it also maintains the order of the index (important for 1003 * priority queues) and fits in the unsigned short variable. 1004 */ 1005 return seq * 2 - is_ccs; 1006 } 1007 1008 int dtls1_retransmit_buffered_messages(SSL *s) 1009 { 1010 pqueue *sent = s->d1->sent_messages; 1011 piterator iter; 1012 pitem *item; 1013 hm_fragment *frag; 1014 int found = 0; 1015 1016 iter = pqueue_iterator(sent); 1017 1018 for (item = pqueue_next(&iter); item != NULL; item = pqueue_next(&iter)) { 1019 frag = (hm_fragment *)item->data; 1020 if (dtls1_retransmit_message(s, (unsigned short) 1021 dtls1_get_queue_priority 1022 (frag->msg_header.seq, 1023 frag->msg_header.is_ccs), &found) <= 0) 1024 return -1; 1025 } 1026 1027 return 1; 1028 } 1029 1030 int dtls1_buffer_message(SSL *s, int is_ccs) 1031 { 1032 pitem *item; 1033 hm_fragment *frag; 1034 unsigned char seq64be[8]; 1035 1036 /* 1037 * this function is called immediately after a message has been 1038 * serialized 1039 */ 1040 if (!ossl_assert(s->init_off == 0)) 1041 return 0; 1042 1043 frag = dtls1_hm_fragment_new(s->init_num, 0); 1044 if (frag == NULL) 1045 return 0; 1046 1047 memcpy(frag->fragment, s->init_buf->data, s->init_num); 1048 1049 if (is_ccs) { 1050 /* For DTLS1_BAD_VER the header length is non-standard */ 1051 if (!ossl_assert(s->d1->w_msg_hdr.msg_len + 1052 ((s->version == 1053 DTLS1_BAD_VER) ? 3 : DTLS1_CCS_HEADER_LENGTH) 1054 == (unsigned int)s->init_num)) 1055 return 0; 1056 } else { 1057 if (!ossl_assert(s->d1->w_msg_hdr.msg_len + 1058 DTLS1_HM_HEADER_LENGTH == (unsigned int)s->init_num)) 1059 return 0; 1060 } 1061 1062 frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len; 1063 frag->msg_header.seq = s->d1->w_msg_hdr.seq; 1064 frag->msg_header.type = s->d1->w_msg_hdr.type; 1065 frag->msg_header.frag_off = 0; 1066 frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len; 1067 frag->msg_header.is_ccs = is_ccs; 1068 1069 /* save current state */ 1070 frag->msg_header.saved_retransmit_state.enc_write_ctx = s->enc_write_ctx; 1071 frag->msg_header.saved_retransmit_state.write_hash = s->write_hash; 1072 frag->msg_header.saved_retransmit_state.compress = s->compress; 1073 frag->msg_header.saved_retransmit_state.session = s->session; 1074 frag->msg_header.saved_retransmit_state.epoch = 1075 DTLS_RECORD_LAYER_get_w_epoch(&s->rlayer); 1076 1077 memset(seq64be, 0, sizeof(seq64be)); 1078 seq64be[6] = 1079 (unsigned 1080 char)(dtls1_get_queue_priority(frag->msg_header.seq, 1081 frag->msg_header.is_ccs) >> 8); 1082 seq64be[7] = 1083 (unsigned 1084 char)(dtls1_get_queue_priority(frag->msg_header.seq, 1085 frag->msg_header.is_ccs)); 1086 1087 item = pitem_new(seq64be, frag); 1088 if (item == NULL) { 1089 dtls1_hm_fragment_free(frag); 1090 return 0; 1091 } 1092 1093 pqueue_insert(s->d1->sent_messages, item); 1094 return 1; 1095 } 1096 1097 int dtls1_retransmit_message(SSL *s, unsigned short seq, int *found) 1098 { 1099 int ret; 1100 /* XDTLS: for now assuming that read/writes are blocking */ 1101 pitem *item; 1102 hm_fragment *frag; 1103 unsigned long header_length; 1104 unsigned char seq64be[8]; 1105 struct dtls1_retransmit_state saved_state; 1106 1107 /* XDTLS: the requested message ought to be found, otherwise error */ 1108 memset(seq64be, 0, sizeof(seq64be)); 1109 seq64be[6] = (unsigned char)(seq >> 8); 1110 seq64be[7] = (unsigned char)seq; 1111 1112 item = pqueue_find(s->d1->sent_messages, seq64be); 1113 if (item == NULL) { 1114 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DTLS1_RETRANSMIT_MESSAGE, 1115 ERR_R_INTERNAL_ERROR); 1116 *found = 0; 1117 return 0; 1118 } 1119 1120 *found = 1; 1121 frag = (hm_fragment *)item->data; 1122 1123 if (frag->msg_header.is_ccs) 1124 header_length = DTLS1_CCS_HEADER_LENGTH; 1125 else 1126 header_length = DTLS1_HM_HEADER_LENGTH; 1127 1128 memcpy(s->init_buf->data, frag->fragment, 1129 frag->msg_header.msg_len + header_length); 1130 s->init_num = frag->msg_header.msg_len + header_length; 1131 1132 dtls1_set_message_header_int(s, frag->msg_header.type, 1133 frag->msg_header.msg_len, 1134 frag->msg_header.seq, 0, 1135 frag->msg_header.frag_len); 1136 1137 /* save current state */ 1138 saved_state.enc_write_ctx = s->enc_write_ctx; 1139 saved_state.write_hash = s->write_hash; 1140 saved_state.compress = s->compress; 1141 saved_state.session = s->session; 1142 saved_state.epoch = DTLS_RECORD_LAYER_get_w_epoch(&s->rlayer); 1143 1144 s->d1->retransmitting = 1; 1145 1146 /* restore state in which the message was originally sent */ 1147 s->enc_write_ctx = frag->msg_header.saved_retransmit_state.enc_write_ctx; 1148 s->write_hash = frag->msg_header.saved_retransmit_state.write_hash; 1149 s->compress = frag->msg_header.saved_retransmit_state.compress; 1150 s->session = frag->msg_header.saved_retransmit_state.session; 1151 DTLS_RECORD_LAYER_set_saved_w_epoch(&s->rlayer, 1152 frag->msg_header. 1153 saved_retransmit_state.epoch); 1154 1155 ret = dtls1_do_write(s, frag->msg_header.is_ccs ? 1156 SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE); 1157 1158 /* restore current state */ 1159 s->enc_write_ctx = saved_state.enc_write_ctx; 1160 s->write_hash = saved_state.write_hash; 1161 s->compress = saved_state.compress; 1162 s->session = saved_state.session; 1163 DTLS_RECORD_LAYER_set_saved_w_epoch(&s->rlayer, saved_state.epoch); 1164 1165 s->d1->retransmitting = 0; 1166 1167 (void)BIO_flush(s->wbio); 1168 return ret; 1169 } 1170 1171 void dtls1_set_message_header(SSL *s, 1172 unsigned char mt, size_t len, 1173 size_t frag_off, size_t frag_len) 1174 { 1175 if (frag_off == 0) { 1176 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq; 1177 s->d1->next_handshake_write_seq++; 1178 } 1179 1180 dtls1_set_message_header_int(s, mt, len, s->d1->handshake_write_seq, 1181 frag_off, frag_len); 1182 } 1183 1184 /* don't actually do the writing, wait till the MTU has been retrieved */ 1185 static void 1186 dtls1_set_message_header_int(SSL *s, unsigned char mt, 1187 size_t len, unsigned short seq_num, 1188 size_t frag_off, size_t frag_len) 1189 { 1190 struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr; 1191 1192 msg_hdr->type = mt; 1193 msg_hdr->msg_len = len; 1194 msg_hdr->seq = seq_num; 1195 msg_hdr->frag_off = frag_off; 1196 msg_hdr->frag_len = frag_len; 1197 } 1198 1199 static void 1200 dtls1_fix_message_header(SSL *s, size_t frag_off, size_t frag_len) 1201 { 1202 struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr; 1203 1204 msg_hdr->frag_off = frag_off; 1205 msg_hdr->frag_len = frag_len; 1206 } 1207 1208 static unsigned char *dtls1_write_message_header(SSL *s, unsigned char *p) 1209 { 1210 struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr; 1211 1212 *p++ = msg_hdr->type; 1213 l2n3(msg_hdr->msg_len, p); 1214 1215 s2n(msg_hdr->seq, p); 1216 l2n3(msg_hdr->frag_off, p); 1217 l2n3(msg_hdr->frag_len, p); 1218 1219 return p; 1220 } 1221 1222 void dtls1_get_message_header(unsigned char *data, struct hm_header_st *msg_hdr) 1223 { 1224 memset(msg_hdr, 0, sizeof(*msg_hdr)); 1225 msg_hdr->type = *(data++); 1226 n2l3(data, msg_hdr->msg_len); 1227 1228 n2s(data, msg_hdr->seq); 1229 n2l3(data, msg_hdr->frag_off); 1230 n2l3(data, msg_hdr->frag_len); 1231 } 1232 1233 int dtls1_set_handshake_header(SSL *s, WPACKET *pkt, int htype) 1234 { 1235 unsigned char *header; 1236 1237 if (htype == SSL3_MT_CHANGE_CIPHER_SPEC) { 1238 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq; 1239 dtls1_set_message_header_int(s, SSL3_MT_CCS, 0, 1240 s->d1->handshake_write_seq, 0, 0); 1241 if (!WPACKET_put_bytes_u8(pkt, SSL3_MT_CCS)) 1242 return 0; 1243 } else { 1244 dtls1_set_message_header(s, htype, 0, 0, 0); 1245 /* 1246 * We allocate space at the start for the message header. This gets 1247 * filled in later 1248 */ 1249 if (!WPACKET_allocate_bytes(pkt, DTLS1_HM_HEADER_LENGTH, &header) 1250 || !WPACKET_start_sub_packet(pkt)) 1251 return 0; 1252 } 1253 1254 return 1; 1255 } 1256 1257 int dtls1_close_construct_packet(SSL *s, WPACKET *pkt, int htype) 1258 { 1259 size_t msglen; 1260 1261 if ((htype != SSL3_MT_CHANGE_CIPHER_SPEC && !WPACKET_close(pkt)) 1262 || !WPACKET_get_length(pkt, &msglen) 1263 || msglen > INT_MAX) 1264 return 0; 1265 1266 if (htype != SSL3_MT_CHANGE_CIPHER_SPEC) { 1267 s->d1->w_msg_hdr.msg_len = msglen - DTLS1_HM_HEADER_LENGTH; 1268 s->d1->w_msg_hdr.frag_len = msglen - DTLS1_HM_HEADER_LENGTH; 1269 } 1270 s->init_num = (int)msglen; 1271 s->init_off = 0; 1272 1273 if (htype != DTLS1_MT_HELLO_VERIFY_REQUEST) { 1274 /* Buffer the message to handle re-xmits */ 1275 if (!dtls1_buffer_message(s, htype == SSL3_MT_CHANGE_CIPHER_SPEC 1276 ? 1 : 0)) 1277 return 0; 1278 } 1279 1280 return 1; 1281 } 1282
Indexes created Sun Mar 01 05:31:48 UTC 2026