1 /* $OpenBSD: d1_both.c,v 1.81 2022/02/05 14:54:10 jsing Exp $ */ 2 /* 3 * DTLS implementation written by Nagendra Modadugu 4 * (nagendra@cs.stanford.edu) for the OpenSSL project 2005. 5 */ 6 /* ==================================================================== 7 * Copyright (c) 1998-2005 The OpenSSL Project. All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in 18 * the documentation and/or other materials provided with the 19 * distribution. 20 * 21 * 3. All advertising materials mentioning features or use of this 22 * software must display the following acknowledgment: 23 * "This product includes software developed by the OpenSSL Project 24 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" 25 * 26 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to 27 * endorse or promote products derived from this software without 28 * prior written permission. For written permission, please contact 29 * openssl-core@openssl.org. 30 * 31 * 5. Products derived from this software may not be called "OpenSSL" 32 * nor may "OpenSSL" appear in their names without prior written 33 * permission of the OpenSSL Project. 34 * 35 * 6. Redistributions of any form whatsoever must retain the following 36 * acknowledgment: 37 * "This product includes software developed by the OpenSSL Project 38 * for use in the OpenSSL Toolkit (http://www.openssl.org/)" 39 * 40 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY 41 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 43 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR 44 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 45 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 46 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 47 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 49 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 50 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 51 * OF THE POSSIBILITY OF SUCH DAMAGE. 52 * ==================================================================== 53 * 54 * This product includes cryptographic software written by Eric Young 55 * (eay@cryptsoft.com). This product includes software written by Tim 56 * Hudson (tjh@cryptsoft.com). 57 * 58 */ 59 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) 60 * All rights reserved. 61 * 62 * This package is an SSL implementation written 63 * by Eric Young (eay@cryptsoft.com). 64 * The implementation was written so as to conform with Netscapes SSL. 65 * 66 * This library is free for commercial and non-commercial use as long as 67 * the following conditions are aheared to. The following conditions 68 * apply to all code found in this distribution, be it the RC4, RSA, 69 * lhash, DES, etc., code; not just the SSL code. The SSL documentation 70 * included with this distribution is covered by the same copyright terms 71 * except that the holder is Tim Hudson (tjh@cryptsoft.com). 72 * 73 * Copyright remains Eric Young's, and as such any Copyright notices in 74 * the code are not to be removed. 75 * If this package is used in a product, Eric Young should be given attribution 76 * as the author of the parts of the library used. 77 * This can be in the form of a textual message at program startup or 78 * in documentation (online or textual) provided with the package. 79 * 80 * Redistribution and use in source and binary forms, with or without 81 * modification, are permitted provided that the following conditions 82 * are met: 83 * 1. Redistributions of source code must retain the copyright 84 * notice, this list of conditions and the following disclaimer. 85 * 2. Redistributions in binary form must reproduce the above copyright 86 * notice, this list of conditions and the following disclaimer in the 87 * documentation and/or other materials provided with the distribution. 88 * 3. All advertising materials mentioning features or use of this software 89 * must display the following acknowledgement: 90 * "This product includes cryptographic software written by 91 * Eric Young (eay@cryptsoft.com)" 92 * The word 'cryptographic' can be left out if the rouines from the library 93 * being used are not cryptographic related :-). 94 * 4. If you include any Windows specific code (or a derivative thereof) from 95 * the apps directory (application code) you must include an acknowledgement: 96 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" 97 * 98 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND 99 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 100 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 101 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 102 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 103 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 104 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 105 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 106 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 107 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 108 * SUCH DAMAGE. 109 * 110 * The licence and distribution terms for any publically available version or 111 * derivative of this code cannot be changed. i.e. this code cannot simply be 112 * copied and put under another distribution licence 113 * [including the GNU Public Licence.] 114 */ 115 116 #include <limits.h> 117 #include <stdio.h> 118 #include <string.h> 119 120 #include <openssl/buffer.h> 121 #include <openssl/evp.h> 122 #include <openssl/objects.h> 123 #include <openssl/x509.h> 124 125 #include "bytestring.h" 126 #include "dtls_locl.h" 127 #include "pqueue.h" 128 #include "ssl_locl.h" 129 130 #define RSMBLY_BITMASK_SIZE(msg_len) (((msg_len) + 7) / 8) 131 132 #define RSMBLY_BITMASK_MARK(bitmask, start, end) { \ 133 if ((end) - (start) <= 8) { \ 134 long ii; \ 135 for (ii = (start); ii < (end); ii++) bitmask[((ii) >> 3)] |= (1 << ((ii) & 7)); \ 136 } else { \ 137 long ii; \ 138 bitmask[((start) >> 3)] |= bitmask_start_values[((start) & 7)]; \ 139 for (ii = (((start) >> 3) + 1); ii < ((((end) - 1)) >> 3); ii++) bitmask[ii] = 0xff; \ 140 bitmask[(((end) - 1) >> 3)] |= bitmask_end_values[((end) & 7)]; \ 141 } } 142 143 #define RSMBLY_BITMASK_IS_COMPLETE(bitmask, msg_len, is_complete) { \ 144 long ii; \ 145 OPENSSL_assert((msg_len) > 0); \ 146 is_complete = 1; \ 147 if (bitmask[(((msg_len) - 1) >> 3)] != bitmask_end_values[((msg_len) & 7)]) is_complete = 0; \ 148 if (is_complete) for (ii = (((msg_len) - 1) >> 3) - 1; ii >= 0 ; ii--) \ 149 if (bitmask[ii] != 0xff) { is_complete = 0; break; } } 150 151 static const unsigned char bitmask_start_values[] = { 152 0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80 153 }; 154 static const unsigned char bitmask_end_values[] = { 155 0xff, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f 156 }; 157 158 /* XDTLS: figure out the right values */ 159 static const unsigned int g_probable_mtu[] = {1500 - 28, 512 - 28, 256 - 28}; 160 161 static unsigned int dtls1_guess_mtu(unsigned int curr_mtu); 162 static void dtls1_fix_message_header(SSL *s, unsigned long frag_off, 163 unsigned long frag_len); 164 static int dtls1_write_message_header(const struct hm_header_st *msg_hdr, 165 unsigned long frag_off, unsigned long frag_len, unsigned char *p); 166 static long dtls1_get_message_fragment(SSL *s, int st1, int stn, long max, 167 int *ok); 168 169 void dtls1_hm_fragment_free(hm_fragment *frag); 170 171 static hm_fragment * 172 dtls1_hm_fragment_new(unsigned long frag_len, int reassembly) 173 { 174 hm_fragment *frag; 175 176 if ((frag = calloc(1, sizeof(*frag))) == NULL) 177 goto err; 178 179 if (frag_len > 0) { 180 if ((frag->fragment = calloc(1, frag_len)) == NULL) 181 goto err; 182 } 183 184 /* Initialize reassembly bitmask if necessary. */ 185 if (reassembly) { 186 if ((frag->reassembly = calloc(1, 187 RSMBLY_BITMASK_SIZE(frag_len))) == NULL) 188 goto err; 189 } 190 191 return frag; 192 193 err: 194 dtls1_hm_fragment_free(frag); 195 return NULL; 196 } 197 198 void 199 dtls1_hm_fragment_free(hm_fragment *frag) 200 { 201 if (frag == NULL) 202 return; 203 204 free(frag->fragment); 205 free(frag->reassembly); 206 free(frag); 207 } 208 209 /* send s->internal->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or SSL3_RT_CHANGE_CIPHER_SPEC) */ 210 int 211 dtls1_do_write(SSL *s, int type) 212 { 213 int ret; 214 int curr_mtu; 215 unsigned int len, frag_off; 216 size_t overhead; 217 218 /* AHA! Figure out the MTU, and stick to the right size */ 219 if (s->d1->mtu < dtls1_min_mtu() && 220 !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) { 221 s->d1->mtu = BIO_ctrl(SSL_get_wbio(s), 222 BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL); 223 224 /* 225 * I've seen the kernel return bogus numbers when it 226 * doesn't know the MTU (ie., the initial write), so just 227 * make sure we have a reasonable number 228 */ 229 if (s->d1->mtu < dtls1_min_mtu()) { 230 s->d1->mtu = 0; 231 s->d1->mtu = dtls1_guess_mtu(s->d1->mtu); 232 BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU, 233 s->d1->mtu, NULL); 234 } 235 } 236 237 OPENSSL_assert(s->d1->mtu >= dtls1_min_mtu()); 238 /* should have something reasonable now */ 239 240 if (s->internal->init_off == 0 && type == SSL3_RT_HANDSHAKE) 241 OPENSSL_assert(s->internal->init_num == 242 (int)s->d1->w_msg_hdr.msg_len + DTLS1_HM_HEADER_LENGTH); 243 244 if (!tls12_record_layer_write_overhead(s->internal->rl, &overhead)) 245 return -1; 246 247 frag_off = 0; 248 while (s->internal->init_num) { 249 curr_mtu = s->d1->mtu - BIO_wpending(SSL_get_wbio(s)) - 250 DTLS1_RT_HEADER_LENGTH - overhead; 251 252 if (curr_mtu <= DTLS1_HM_HEADER_LENGTH) { 253 /* grr.. we could get an error if MTU picked was wrong */ 254 ret = BIO_flush(SSL_get_wbio(s)); 255 if (ret <= 0) 256 return ret; 257 curr_mtu = s->d1->mtu - DTLS1_RT_HEADER_LENGTH - 258 overhead; 259 } 260 261 if (s->internal->init_num > curr_mtu) 262 len = curr_mtu; 263 else 264 len = s->internal->init_num; 265 266 /* XDTLS: this function is too long. split out the CCS part */ 267 if (type == SSL3_RT_HANDSHAKE) { 268 if (s->internal->init_off != 0) { 269 OPENSSL_assert(s->internal->init_off > DTLS1_HM_HEADER_LENGTH); 270 s->internal->init_off -= DTLS1_HM_HEADER_LENGTH; 271 s->internal->init_num += DTLS1_HM_HEADER_LENGTH; 272 273 if (s->internal->init_num > curr_mtu) 274 len = curr_mtu; 275 else 276 len = s->internal->init_num; 277 } 278 279 dtls1_fix_message_header(s, frag_off, 280 len - DTLS1_HM_HEADER_LENGTH); 281 282 if (!dtls1_write_message_header(&s->d1->w_msg_hdr, 283 s->d1->w_msg_hdr.frag_off, s->d1->w_msg_hdr.frag_len, 284 (unsigned char *)&s->internal->init_buf->data[s->internal->init_off])) 285 return -1; 286 287 OPENSSL_assert(len >= DTLS1_HM_HEADER_LENGTH); 288 } 289 290 ret = dtls1_write_bytes(s, type, 291 &s->internal->init_buf->data[s->internal->init_off], len); 292 if (ret < 0) { 293 /* 294 * Might need to update MTU here, but we don't know 295 * which previous packet caused the failure -- so 296 * can't really retransmit anything. continue as 297 * if everything is fine and wait for an alert to 298 * handle the retransmit 299 */ 300 if (BIO_ctrl(SSL_get_wbio(s), 301 BIO_CTRL_DGRAM_MTU_EXCEEDED, 0, NULL) > 0) 302 s->d1->mtu = BIO_ctrl(SSL_get_wbio(s), 303 BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL); 304 else 305 return (-1); 306 } else { 307 308 /* 309 * Bad if this assert fails, only part of the 310 * handshake message got sent. but why would 311 * this happen? 312 */ 313 OPENSSL_assert(len == (unsigned int)ret); 314 315 if (type == SSL3_RT_HANDSHAKE && 316 !s->d1->retransmitting) { 317 /* 318 * Should not be done for 'Hello Request's, 319 * but in that case we'll ignore the result 320 * anyway 321 */ 322 unsigned char *p = (unsigned char *)&s->internal->init_buf->data[s->internal->init_off]; 323 const struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr; 324 int xlen; 325 326 if (frag_off == 0) { 327 /* 328 * Reconstruct message header is if it 329 * is being sent in single fragment 330 */ 331 if (!dtls1_write_message_header(msg_hdr, 332 0, msg_hdr->msg_len, p)) 333 return (-1); 334 xlen = ret; 335 } else { 336 p += DTLS1_HM_HEADER_LENGTH; 337 xlen = ret - DTLS1_HM_HEADER_LENGTH; 338 } 339 340 tls1_transcript_record(s, p, xlen); 341 } 342 343 if (ret == s->internal->init_num) { 344 if (s->internal->msg_callback) 345 s->internal->msg_callback(1, s->version, type, 346 s->internal->init_buf->data, 347 (size_t)(s->internal->init_off + s->internal->init_num), 348 s, s->internal->msg_callback_arg); 349 350 s->internal->init_off = 0; 351 /* done writing this message */ 352 s->internal->init_num = 0; 353 354 return (1); 355 } 356 s->internal->init_off += ret; 357 s->internal->init_num -= ret; 358 frag_off += (ret -= DTLS1_HM_HEADER_LENGTH); 359 } 360 } 361 return (0); 362 } 363 364 365 /* 366 * Obtain handshake message of message type 'mt' (any if mt == -1), 367 * maximum acceptable body length 'max'. 368 * Read an entire handshake message. Handshake messages arrive in 369 * fragments. 370 */ 371 int 372 dtls1_get_message(SSL *s, int st1, int stn, int mt, long max) 373 { 374 struct hm_header_st *msg_hdr; 375 unsigned char *p; 376 unsigned long msg_len; 377 int i, al, ok; 378 379 /* 380 * s3->internal->tmp is used to store messages that are unexpected, caused 381 * by the absence of an optional handshake message 382 */ 383 if (s->s3->hs.tls12.reuse_message) { 384 s->s3->hs.tls12.reuse_message = 0; 385 if ((mt >= 0) && (s->s3->hs.tls12.message_type != mt)) { 386 al = SSL_AD_UNEXPECTED_MESSAGE; 387 SSLerror(s, SSL_R_UNEXPECTED_MESSAGE); 388 goto fatal_err; 389 } 390 s->internal->init_msg = s->internal->init_buf->data + DTLS1_HM_HEADER_LENGTH; 391 s->internal->init_num = (int)s->s3->hs.tls12.message_size; 392 return 1; 393 } 394 395 msg_hdr = &s->d1->r_msg_hdr; 396 memset(msg_hdr, 0, sizeof(struct hm_header_st)); 397 398 again: 399 i = dtls1_get_message_fragment(s, st1, stn, max, &ok); 400 if (i == DTLS1_HM_BAD_FRAGMENT || 401 i == DTLS1_HM_FRAGMENT_RETRY) /* bad fragment received */ 402 goto again; 403 else if (i <= 0 && !ok) 404 return i; 405 406 p = (unsigned char *)s->internal->init_buf->data; 407 msg_len = msg_hdr->msg_len; 408 409 /* reconstruct message header */ 410 if (!dtls1_write_message_header(msg_hdr, 0, msg_len, p)) 411 return -1; 412 413 msg_len += DTLS1_HM_HEADER_LENGTH; 414 415 tls1_transcript_record(s, p, msg_len); 416 if (s->internal->msg_callback) 417 s->internal->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, p, msg_len, 418 s, s->internal->msg_callback_arg); 419 420 memset(msg_hdr, 0, sizeof(struct hm_header_st)); 421 422 /* Don't change sequence numbers while listening */ 423 if (!s->d1->listen) 424 s->d1->handshake_read_seq++; 425 426 s->internal->init_msg = s->internal->init_buf->data + DTLS1_HM_HEADER_LENGTH; 427 return 1; 428 429 fatal_err: 430 ssl3_send_alert(s, SSL3_AL_FATAL, al); 431 return -1; 432 } 433 434 static int 435 dtls1_preprocess_fragment(SSL *s, struct hm_header_st *msg_hdr, int max) 436 { 437 size_t frag_off, frag_len, msg_len; 438 439 msg_len = msg_hdr->msg_len; 440 frag_off = msg_hdr->frag_off; 441 frag_len = msg_hdr->frag_len; 442 443 /* sanity checking */ 444 if ((frag_off + frag_len) > msg_len) { 445 SSLerror(s, SSL_R_EXCESSIVE_MESSAGE_SIZE); 446 return SSL_AD_ILLEGAL_PARAMETER; 447 } 448 449 if ((frag_off + frag_len) > (unsigned long)max) { 450 SSLerror(s, SSL_R_EXCESSIVE_MESSAGE_SIZE); 451 return SSL_AD_ILLEGAL_PARAMETER; 452 } 453 454 if ( s->d1->r_msg_hdr.frag_off == 0) /* first fragment */ 455 { 456 /* 457 * msg_len is limited to 2^24, but is effectively checked 458 * against max above 459 */ 460 if (!BUF_MEM_grow_clean(s->internal->init_buf, 461 msg_len + DTLS1_HM_HEADER_LENGTH)) { 462 SSLerror(s, ERR_R_BUF_LIB); 463 return SSL_AD_INTERNAL_ERROR; 464 } 465 466 s->s3->hs.tls12.message_size = msg_len; 467 s->d1->r_msg_hdr.msg_len = msg_len; 468 s->s3->hs.tls12.message_type = msg_hdr->type; 469 s->d1->r_msg_hdr.type = msg_hdr->type; 470 s->d1->r_msg_hdr.seq = msg_hdr->seq; 471 } else if (msg_len != s->d1->r_msg_hdr.msg_len) { 472 /* 473 * They must be playing with us! BTW, failure to enforce 474 * upper limit would open possibility for buffer overrun. 475 */ 476 SSLerror(s, SSL_R_EXCESSIVE_MESSAGE_SIZE); 477 return SSL_AD_ILLEGAL_PARAMETER; 478 } 479 480 return 0; /* no error */ 481 } 482 483 static int 484 dtls1_retrieve_buffered_fragment(SSL *s, long max, int *ok) 485 { 486 /* 487 * (0) check whether the desired fragment is available 488 * if so: 489 * (1) copy over the fragment to s->internal->init_buf->data[] 490 * (2) update s->internal->init_num 491 */ 492 pitem *item; 493 hm_fragment *frag; 494 int al; 495 496 *ok = 0; 497 item = pqueue_peek(s->d1->buffered_messages); 498 if (item == NULL) 499 return 0; 500 501 frag = (hm_fragment *)item->data; 502 503 /* Don't return if reassembly still in progress */ 504 if (frag->reassembly != NULL) 505 return 0; 506 507 if (s->d1->handshake_read_seq == frag->msg_header.seq) { 508 unsigned long frag_len = frag->msg_header.frag_len; 509 pqueue_pop(s->d1->buffered_messages); 510 511 al = dtls1_preprocess_fragment(s, &frag->msg_header, max); 512 513 if (al == 0) /* no alert */ 514 { 515 unsigned char *p = (unsigned char *)s->internal->init_buf->data + DTLS1_HM_HEADER_LENGTH; 516 memcpy(&p[frag->msg_header.frag_off], 517 frag->fragment, frag->msg_header.frag_len); 518 } 519 520 dtls1_hm_fragment_free(frag); 521 pitem_free(item); 522 523 if (al == 0) { 524 *ok = 1; 525 return frag_len; 526 } 527 528 ssl3_send_alert(s, SSL3_AL_FATAL, al); 529 s->internal->init_num = 0; 530 *ok = 0; 531 return -1; 532 } else 533 return 0; 534 } 535 536 /* 537 * dtls1_max_handshake_message_len returns the maximum number of bytes 538 * permitted in a DTLS handshake message for |s|. The minimum is 16KB, 539 * but may be greater if the maximum certificate list size requires it. 540 */ 541 static unsigned long 542 dtls1_max_handshake_message_len(const SSL *s) 543 { 544 unsigned long max_len; 545 546 max_len = DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH; 547 if (max_len < (unsigned long)s->internal->max_cert_list) 548 return s->internal->max_cert_list; 549 return max_len; 550 } 551 552 static int 553 dtls1_reassemble_fragment(SSL *s, struct hm_header_st* msg_hdr, int *ok) 554 { 555 hm_fragment *frag = NULL; 556 pitem *item = NULL; 557 int i = -1, is_complete; 558 unsigned char seq64be[8]; 559 unsigned long frag_len = msg_hdr->frag_len; 560 561 if ((msg_hdr->frag_off + frag_len) > msg_hdr->msg_len || 562 msg_hdr->msg_len > dtls1_max_handshake_message_len(s)) 563 goto err; 564 565 if (frag_len == 0) { 566 i = DTLS1_HM_FRAGMENT_RETRY; 567 goto err; 568 } 569 570 /* Try to find item in queue */ 571 memset(seq64be, 0, sizeof(seq64be)); 572 seq64be[6] = (unsigned char)(msg_hdr->seq >> 8); 573 seq64be[7] = (unsigned char)msg_hdr->seq; 574 item = pqueue_find(s->d1->buffered_messages, seq64be); 575 576 if (item == NULL) { 577 frag = dtls1_hm_fragment_new(msg_hdr->msg_len, 1); 578 if (frag == NULL) 579 goto err; 580 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr)); 581 frag->msg_header.frag_len = frag->msg_header.msg_len; 582 frag->msg_header.frag_off = 0; 583 } else { 584 frag = (hm_fragment*)item->data; 585 if (frag->msg_header.msg_len != msg_hdr->msg_len) { 586 item = NULL; 587 frag = NULL; 588 goto err; 589 } 590 } 591 592 /* 593 * If message is already reassembled, this must be a 594 * retransmit and can be dropped. 595 */ 596 if (frag->reassembly == NULL) { 597 unsigned char devnull [256]; 598 599 while (frag_len) { 600 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, 601 devnull, frag_len > sizeof(devnull) ? 602 sizeof(devnull) : frag_len, 0); 603 if (i <= 0) 604 goto err; 605 frag_len -= i; 606 } 607 i = DTLS1_HM_FRAGMENT_RETRY; 608 goto err; 609 } 610 611 /* read the body of the fragment (header has already been read */ 612 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, 613 frag->fragment + msg_hdr->frag_off, frag_len, 0); 614 if (i <= 0 || (unsigned long)i != frag_len) 615 goto err; 616 617 RSMBLY_BITMASK_MARK(frag->reassembly, (long)msg_hdr->frag_off, 618 (long)(msg_hdr->frag_off + frag_len)); 619 620 RSMBLY_BITMASK_IS_COMPLETE(frag->reassembly, (long)msg_hdr->msg_len, 621 is_complete); 622 623 if (is_complete) { 624 free(frag->reassembly); 625 frag->reassembly = NULL; 626 } 627 628 if (item == NULL) { 629 memset(seq64be, 0, sizeof(seq64be)); 630 seq64be[6] = (unsigned char)(msg_hdr->seq >> 8); 631 seq64be[7] = (unsigned char)(msg_hdr->seq); 632 633 item = pitem_new(seq64be, frag); 634 if (item == NULL) { 635 i = -1; 636 goto err; 637 } 638 639 pqueue_insert(s->d1->buffered_messages, item); 640 } 641 642 return DTLS1_HM_FRAGMENT_RETRY; 643 644 err: 645 if (item == NULL && frag != NULL) 646 dtls1_hm_fragment_free(frag); 647 *ok = 0; 648 return i; 649 } 650 651 652 static int 653 dtls1_process_out_of_seq_message(SSL *s, struct hm_header_st* msg_hdr, int *ok) 654 { 655 int i = -1; 656 hm_fragment *frag = NULL; 657 pitem *item = NULL; 658 unsigned char seq64be[8]; 659 unsigned long frag_len = msg_hdr->frag_len; 660 661 if ((msg_hdr->frag_off + frag_len) > msg_hdr->msg_len) 662 goto err; 663 664 /* Try to find item in queue, to prevent duplicate entries */ 665 memset(seq64be, 0, sizeof(seq64be)); 666 seq64be[6] = (unsigned char) (msg_hdr->seq >> 8); 667 seq64be[7] = (unsigned char) msg_hdr->seq; 668 item = pqueue_find(s->d1->buffered_messages, seq64be); 669 670 /* 671 * If we already have an entry and this one is a fragment, 672 * don't discard it and rather try to reassemble it. 673 */ 674 if (item != NULL && frag_len < msg_hdr->msg_len) 675 item = NULL; 676 677 /* 678 * Discard the message if sequence number was already there, is 679 * too far in the future, already in the queue or if we received 680 * a FINISHED before the SERVER_HELLO, which then must be a stale 681 * retransmit. 682 */ 683 if (msg_hdr->seq <= s->d1->handshake_read_seq || 684 msg_hdr->seq > s->d1->handshake_read_seq + 10 || item != NULL || 685 (s->d1->handshake_read_seq == 0 && 686 msg_hdr->type == SSL3_MT_FINISHED)) { 687 unsigned char devnull [256]; 688 689 while (frag_len) { 690 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, 691 devnull, frag_len > sizeof(devnull) ? 692 sizeof(devnull) : frag_len, 0); 693 if (i <= 0) 694 goto err; 695 frag_len -= i; 696 } 697 } else { 698 if (frag_len < msg_hdr->msg_len) 699 return dtls1_reassemble_fragment(s, msg_hdr, ok); 700 701 if (frag_len > dtls1_max_handshake_message_len(s)) 702 goto err; 703 704 frag = dtls1_hm_fragment_new(frag_len, 0); 705 if (frag == NULL) 706 goto err; 707 708 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr)); 709 710 if (frag_len) { 711 /* read the body of the fragment (header has already been read */ 712 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, 713 frag->fragment, frag_len, 0); 714 if (i <= 0 || (unsigned long)i != frag_len) 715 goto err; 716 } 717 718 memset(seq64be, 0, sizeof(seq64be)); 719 seq64be[6] = (unsigned char)(msg_hdr->seq >> 8); 720 seq64be[7] = (unsigned char)(msg_hdr->seq); 721 722 item = pitem_new(seq64be, frag); 723 if (item == NULL) 724 goto err; 725 726 pqueue_insert(s->d1->buffered_messages, item); 727 } 728 729 return DTLS1_HM_FRAGMENT_RETRY; 730 731 err: 732 if (item == NULL && frag != NULL) 733 dtls1_hm_fragment_free(frag); 734 *ok = 0; 735 return i; 736 } 737 738 739 static long 740 dtls1_get_message_fragment(SSL *s, int st1, int stn, long max, int *ok) 741 { 742 unsigned char wire[DTLS1_HM_HEADER_LENGTH]; 743 unsigned long len, frag_off, frag_len; 744 struct hm_header_st msg_hdr; 745 int i, al; 746 CBS cbs; 747 748 again: 749 /* see if we have the required fragment already */ 750 if ((frag_len = dtls1_retrieve_buffered_fragment(s, max, ok)) || *ok) { 751 if (*ok) 752 s->internal->init_num = frag_len; 753 return frag_len; 754 } 755 756 /* read handshake message header */ 757 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, wire, 758 DTLS1_HM_HEADER_LENGTH, 0); 759 if (i <= 0) { 760 /* nbio, or an error */ 761 s->internal->rwstate = SSL_READING; 762 *ok = 0; 763 return i; 764 } 765 766 CBS_init(&cbs, wire, i); 767 if (!dtls1_get_message_header(&cbs, &msg_hdr)) { 768 /* Handshake fails if message header is incomplete. */ 769 al = SSL_AD_UNEXPECTED_MESSAGE; 770 SSLerror(s, SSL_R_UNEXPECTED_MESSAGE); 771 goto fatal_err; 772 } 773 774 /* 775 * if this is a future (or stale) message it gets buffered 776 * (or dropped)--no further processing at this time 777 * While listening, we accept seq 1 (ClientHello with cookie) 778 * although we're still expecting seq 0 (ClientHello) 779 */ 780 if (msg_hdr.seq != s->d1->handshake_read_seq && 781 !(s->d1->listen && msg_hdr.seq == 1)) 782 return dtls1_process_out_of_seq_message(s, &msg_hdr, ok); 783 784 len = msg_hdr.msg_len; 785 frag_off = msg_hdr.frag_off; 786 frag_len = msg_hdr.frag_len; 787 788 if (frag_len && frag_len < len) 789 return dtls1_reassemble_fragment(s, &msg_hdr, ok); 790 791 if (!s->server && s->d1->r_msg_hdr.frag_off == 0 && 792 wire[0] == SSL3_MT_HELLO_REQUEST) { 793 /* 794 * The server may always send 'Hello Request' messages -- 795 * we are doing a handshake anyway now, so ignore them 796 * if their format is correct. Does not count for 797 * 'Finished' MAC. 798 */ 799 if (wire[1] == 0 && wire[2] == 0 && wire[3] == 0) { 800 if (s->internal->msg_callback) 801 s->internal->msg_callback(0, s->version, 802 SSL3_RT_HANDSHAKE, wire, 803 DTLS1_HM_HEADER_LENGTH, s, 804 s->internal->msg_callback_arg); 805 806 s->internal->init_num = 0; 807 goto again; 808 } 809 else /* Incorrectly formated Hello request */ 810 { 811 al = SSL_AD_UNEXPECTED_MESSAGE; 812 SSLerror(s, SSL_R_UNEXPECTED_MESSAGE); 813 goto fatal_err; 814 } 815 } 816 817 if ((al = dtls1_preprocess_fragment(s, &msg_hdr, max))) 818 goto fatal_err; 819 820 /* XDTLS: ressurect this when restart is in place */ 821 s->s3->hs.state = stn; 822 823 if (frag_len > 0) { 824 unsigned char *p = (unsigned char *)s->internal->init_buf->data + DTLS1_HM_HEADER_LENGTH; 825 826 i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, 827 &p[frag_off], frag_len, 0); 828 /* XDTLS: fix this--message fragments cannot span multiple packets */ 829 if (i <= 0) { 830 s->internal->rwstate = SSL_READING; 831 *ok = 0; 832 return i; 833 } 834 } else 835 i = 0; 836 837 /* 838 * XDTLS: an incorrectly formatted fragment should cause the 839 * handshake to fail 840 */ 841 if (i != (int)frag_len) { 842 al = SSL_AD_ILLEGAL_PARAMETER; 843 SSLerror(s, SSL_R_SSLV3_ALERT_ILLEGAL_PARAMETER); 844 goto fatal_err; 845 } 846 847 /* 848 * Note that s->internal->init_num is *not* used as current offset in 849 * s->internal->init_buf->data, but as a counter summing up fragments' 850 * lengths: as soon as they sum up to handshake packet 851 * length, we assume we have got all the fragments. 852 */ 853 s->internal->init_num = frag_len; 854 *ok = 1; 855 return frag_len; 856 857 fatal_err: 858 ssl3_send_alert(s, SSL3_AL_FATAL, al); 859 s->internal->init_num = 0; 860 861 *ok = 0; 862 return (-1); 863 } 864 865 int 866 dtls1_read_failed(SSL *s, int code) 867 { 868 if (code > 0) { 869 #ifdef DEBUG 870 fprintf(stderr, "invalid state reached %s:%d", 871 __FILE__, __LINE__); 872 #endif 873 return 1; 874 } 875 876 if (!dtls1_is_timer_expired(s)) { 877 /* 878 * not a timeout, none of our business, let higher layers 879 * handle this. in fact it's probably an error 880 */ 881 return code; 882 } 883 884 if (!SSL_in_init(s)) /* done, no need to send a retransmit */ 885 { 886 BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ); 887 return code; 888 } 889 890 return dtls1_handle_timeout(s); 891 } 892 893 int 894 dtls1_get_queue_priority(unsigned short seq, int is_ccs) 895 { 896 /* 897 * The index of the retransmission queue actually is the message 898 * sequence number, since the queue only contains messages of a 899 * single handshake. However, the ChangeCipherSpec has no message 900 * sequence number and so using only the sequence will result in 901 * the CCS and Finished having the same index. To prevent this, the 902 * sequence number is multiplied by 2. In case of a CCS 1 is 903 * subtracted. This does not only differ CSS and Finished, it also 904 * maintains the order of the index (important for priority queues) 905 * and fits in the unsigned short variable. 906 */ 907 return seq * 2 - is_ccs; 908 } 909 910 int 911 dtls1_retransmit_buffered_messages(SSL *s) 912 { 913 pqueue sent = s->d1->sent_messages; 914 piterator iter; 915 pitem *item; 916 hm_fragment *frag; 917 int found = 0; 918 919 iter = pqueue_iterator(sent); 920 921 for (item = pqueue_next(&iter); item != NULL; 922 item = pqueue_next(&iter)) { 923 frag = (hm_fragment *)item->data; 924 if (dtls1_retransmit_message(s, 925 (unsigned short)dtls1_get_queue_priority( 926 frag->msg_header.seq, frag->msg_header.is_ccs), 0, 927 &found) <= 0 && found) { 928 #ifdef DEBUG 929 fprintf(stderr, "dtls1_retransmit_message() failed\n"); 930 #endif 931 return -1; 932 } 933 } 934 935 return 1; 936 } 937 938 int 939 dtls1_buffer_message(SSL *s, int is_ccs) 940 { 941 pitem *item; 942 hm_fragment *frag; 943 unsigned char seq64be[8]; 944 945 /* Buffer the messsage in order to handle DTLS retransmissions. */ 946 947 /* 948 * This function is called immediately after a message has 949 * been serialized 950 */ 951 OPENSSL_assert(s->internal->init_off == 0); 952 953 frag = dtls1_hm_fragment_new(s->internal->init_num, 0); 954 if (frag == NULL) 955 return 0; 956 957 memcpy(frag->fragment, s->internal->init_buf->data, s->internal->init_num); 958 959 OPENSSL_assert(s->d1->w_msg_hdr.msg_len + 960 (is_ccs ? DTLS1_CCS_HEADER_LENGTH : DTLS1_HM_HEADER_LENGTH) == 961 (unsigned int)s->internal->init_num); 962 963 frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len; 964 frag->msg_header.seq = s->d1->w_msg_hdr.seq; 965 frag->msg_header.type = s->d1->w_msg_hdr.type; 966 frag->msg_header.frag_off = 0; 967 frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len; 968 frag->msg_header.is_ccs = is_ccs; 969 970 /* save current state*/ 971 frag->msg_header.saved_retransmit_state.session = s->session; 972 frag->msg_header.saved_retransmit_state.epoch = 973 tls12_record_layer_write_epoch(s->internal->rl); 974 975 memset(seq64be, 0, sizeof(seq64be)); 976 seq64be[6] = (unsigned char)(dtls1_get_queue_priority( 977 frag->msg_header.seq, frag->msg_header.is_ccs) >> 8); 978 seq64be[7] = (unsigned char)(dtls1_get_queue_priority( 979 frag->msg_header.seq, frag->msg_header.is_ccs)); 980 981 item = pitem_new(seq64be, frag); 982 if (item == NULL) { 983 dtls1_hm_fragment_free(frag); 984 return 0; 985 } 986 987 pqueue_insert(s->d1->sent_messages, item); 988 return 1; 989 } 990 991 int 992 dtls1_retransmit_message(SSL *s, unsigned short seq, unsigned long frag_off, 993 int *found) 994 { 995 int ret; 996 /* XDTLS: for now assuming that read/writes are blocking */ 997 pitem *item; 998 hm_fragment *frag; 999 unsigned long header_length; 1000 unsigned char seq64be[8]; 1001 struct dtls1_retransmit_state saved_state; 1002 1003 /* 1004 OPENSSL_assert(s->internal->init_num == 0); 1005 OPENSSL_assert(s->internal->init_off == 0); 1006 */ 1007 1008 /* XDTLS: the requested message ought to be found, otherwise error */ 1009 memset(seq64be, 0, sizeof(seq64be)); 1010 seq64be[6] = (unsigned char)(seq >> 8); 1011 seq64be[7] = (unsigned char)seq; 1012 1013 item = pqueue_find(s->d1->sent_messages, seq64be); 1014 if (item == NULL) { 1015 #ifdef DEBUG 1016 fprintf(stderr, "retransmit: message %d non-existent\n", seq); 1017 #endif 1018 *found = 0; 1019 return 0; 1020 } 1021 1022 *found = 1; 1023 frag = (hm_fragment *)item->data; 1024 1025 if (frag->msg_header.is_ccs) 1026 header_length = DTLS1_CCS_HEADER_LENGTH; 1027 else 1028 header_length = DTLS1_HM_HEADER_LENGTH; 1029 1030 memcpy(s->internal->init_buf->data, frag->fragment, 1031 frag->msg_header.msg_len + header_length); 1032 s->internal->init_num = frag->msg_header.msg_len + header_length; 1033 1034 dtls1_set_message_header_int(s, frag->msg_header.type, 1035 frag->msg_header.msg_len, frag->msg_header.seq, 0, 1036 frag->msg_header.frag_len); 1037 1038 /* save current state */ 1039 saved_state.session = s->session; 1040 saved_state.epoch = tls12_record_layer_write_epoch(s->internal->rl); 1041 1042 s->d1->retransmitting = 1; 1043 1044 /* restore state in which the message was originally sent */ 1045 s->session = frag->msg_header.saved_retransmit_state.session; 1046 if (!tls12_record_layer_use_write_epoch(s->internal->rl, 1047 frag->msg_header.saved_retransmit_state.epoch)) 1048 return 0; 1049 1050 ret = dtls1_do_write(s, frag->msg_header.is_ccs ? 1051 SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE); 1052 1053 /* restore current state */ 1054 s->session = saved_state.session; 1055 if (!tls12_record_layer_use_write_epoch(s->internal->rl, 1056 saved_state.epoch)) 1057 return 0; 1058 1059 s->d1->retransmitting = 0; 1060 1061 (void)BIO_flush(SSL_get_wbio(s)); 1062 return ret; 1063 } 1064 1065 /* call this function when the buffered messages are no longer needed */ 1066 void 1067 dtls1_clear_record_buffer(SSL *s) 1068 { 1069 hm_fragment *frag; 1070 pitem *item; 1071 1072 for(item = pqueue_pop(s->d1->sent_messages); item != NULL; 1073 item = pqueue_pop(s->d1->sent_messages)) { 1074 frag = item->data; 1075 if (frag->msg_header.is_ccs) 1076 tls12_record_layer_write_epoch_done(s->internal->rl, 1077 frag->msg_header.saved_retransmit_state.epoch); 1078 dtls1_hm_fragment_free(frag); 1079 pitem_free(item); 1080 } 1081 } 1082 1083 void 1084 dtls1_set_message_header(SSL *s, unsigned char mt, unsigned long len, 1085 unsigned long frag_off, unsigned long frag_len) 1086 { 1087 /* Don't change sequence numbers while listening */ 1088 if (frag_off == 0 && !s->d1->listen) { 1089 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq; 1090 s->d1->next_handshake_write_seq++; 1091 } 1092 1093 dtls1_set_message_header_int(s, mt, len, s->d1->handshake_write_seq, 1094 frag_off, frag_len); 1095 } 1096 1097 /* don't actually do the writing, wait till the MTU has been retrieved */ 1098 void 1099 dtls1_set_message_header_int(SSL *s, unsigned char mt, unsigned long len, 1100 unsigned short seq_num, unsigned long frag_off, unsigned long frag_len) 1101 { 1102 struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr; 1103 1104 msg_hdr->type = mt; 1105 msg_hdr->msg_len = len; 1106 msg_hdr->seq = seq_num; 1107 msg_hdr->frag_off = frag_off; 1108 msg_hdr->frag_len = frag_len; 1109 } 1110 1111 static void 1112 dtls1_fix_message_header(SSL *s, unsigned long frag_off, unsigned long frag_len) 1113 { 1114 struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr; 1115 1116 msg_hdr->frag_off = frag_off; 1117 msg_hdr->frag_len = frag_len; 1118 } 1119 1120 static int 1121 dtls1_write_message_header(const struct hm_header_st *msg_hdr, 1122 unsigned long frag_off, unsigned long frag_len, unsigned char *p) 1123 { 1124 CBB cbb; 1125 1126 /* We assume DTLS1_HM_HEADER_LENGTH bytes are available for now... */ 1127 if (!CBB_init_fixed(&cbb, p, DTLS1_HM_HEADER_LENGTH)) 1128 return 0; 1129 if (!CBB_add_u8(&cbb, msg_hdr->type)) 1130 goto err; 1131 if (!CBB_add_u24(&cbb, msg_hdr->msg_len)) 1132 goto err; 1133 if (!CBB_add_u16(&cbb, msg_hdr->seq)) 1134 goto err; 1135 if (!CBB_add_u24(&cbb, frag_off)) 1136 goto err; 1137 if (!CBB_add_u24(&cbb, frag_len)) 1138 goto err; 1139 if (!CBB_finish(&cbb, NULL, NULL)) 1140 goto err; 1141 1142 return 1; 1143 1144 err: 1145 CBB_cleanup(&cbb); 1146 return 0; 1147 } 1148 1149 unsigned int 1150 dtls1_min_mtu(void) 1151 { 1152 return (g_probable_mtu[(sizeof(g_probable_mtu) / 1153 sizeof(g_probable_mtu[0])) - 1]); 1154 } 1155 1156 static unsigned int 1157 dtls1_guess_mtu(unsigned int curr_mtu) 1158 { 1159 unsigned int i; 1160 1161 if (curr_mtu == 0) 1162 return g_probable_mtu[0]; 1163 1164 for (i = 0; i < sizeof(g_probable_mtu) / sizeof(g_probable_mtu[0]); i++) 1165 if (curr_mtu > g_probable_mtu[i]) 1166 return g_probable_mtu[i]; 1167 1168 return curr_mtu; 1169 } 1170 1171 int 1172 dtls1_get_message_header(CBS *header, struct hm_header_st *msg_hdr) 1173 { 1174 uint32_t msg_len, frag_off, frag_len; 1175 uint16_t seq; 1176 uint8_t type; 1177 1178 memset(msg_hdr, 0, sizeof(*msg_hdr)); 1179 1180 if (!CBS_get_u8(header, &type)) 1181 return 0; 1182 if (!CBS_get_u24(header, &msg_len)) 1183 return 0; 1184 if (!CBS_get_u16(header, &seq)) 1185 return 0; 1186 if (!CBS_get_u24(header, &frag_off)) 1187 return 0; 1188 if (!CBS_get_u24(header, &frag_len)) 1189 return 0; 1190 1191 msg_hdr->type = type; 1192 msg_hdr->msg_len = msg_len; 1193 msg_hdr->seq = seq; 1194 msg_hdr->frag_off = frag_off; 1195 msg_hdr->frag_len = frag_len; 1196 1197 return 1; 1198 } 1199