1/* $OpenBSD: ssl_pkt.c,v 1.66 2023/07/11 17:02:47 tb Exp $ */ 2/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) 3 * All rights reserved. 4 * 5 * This package is an SSL implementation written 6 * by Eric Young (eay@cryptsoft.com). 7 * The implementation was written so as to conform with Netscapes SSL. 8 * 9 * This library is free for commercial and non-commercial use as long as 10 * the following conditions are aheared to. The following conditions 11 * apply to all code found in this distribution, be it the RC4, RSA, 12 * lhash, DES, etc., code; not just the SSL code. The SSL documentation 13 * included with this distribution is covered by the same copyright terms 14 * except that the holder is Tim Hudson (tjh@cryptsoft.com). 15 * 16 * Copyright remains Eric Young's, and as such any Copyright notices in 17 * the code are not to be removed. 18 * If this package is used in a product, Eric Young should be given attribution 19 * as the author of the parts of the library used. 20 * This can be in the form of a textual message at program startup or 21 * in documentation (online or textual) provided with the package. 22 * 23 * Redistribution and use in source and binary forms, with or without 24 * modification, are permitted provided that the following conditions 25 * are met: 26 * 1. Redistributions of source code must retain the copyright 27 * notice, this list of conditions and the following disclaimer. 28 * 2. Redistributions in binary form must reproduce the above copyright 29 * notice, this list of conditions and the following disclaimer in the 30 * documentation and/or other materials provided with the distribution. 31 * 3. All advertising materials mentioning features or use of this software 32 * must display the following acknowledgement: 33 * "This product includes cryptographic software written by 34 * Eric Young (eay@cryptsoft.com)" 35 * The word 'cryptographic' can be left out if the rouines from the library 36 * being used are not cryptographic related :-). 37 * 4. If you include any Windows specific code (or a derivative thereof) from 38 * the apps directory (application code) you must include an acknowledgement: 39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" 40 * 41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND 42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 51 * SUCH DAMAGE. 52 * 53 * The licence and distribution terms for any publically available version or 54 * derivative of this code cannot be changed. i.e. this code cannot simply be 55 * copied and put under another distribution licence 56 * [including the GNU Public Licence.] 57 */ 58/* ==================================================================== 59 * Copyright (c) 1998-2002 The OpenSSL Project. All rights reserved. 60 * 61 * Redistribution and use in source and binary forms, with or without 62 * modification, are permitted provided that the following conditions 63 * are met: 64 * 65 * 1. Redistributions of source code must retain the above copyright 66 * notice, this list of conditions and the following disclaimer. 67 * 68 * 2. Redistributions in binary form must reproduce the above copyright 69 * notice, this list of conditions and the following disclaimer in 70 * the documentation and/or other materials provided with the 71 * distribution. 72 * 73 * 3. All advertising materials mentioning features or use of this 74 * software must display the following acknowledgment: 75 * "This product includes software developed by the OpenSSL Project 76 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" 77 * 78 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to 79 * endorse or promote products derived from this software without 80 * prior written permission. For written permission, please contact 81 * openssl-core@openssl.org. 82 * 83 * 5. Products derived from this software may not be called "OpenSSL" 84 * nor may "OpenSSL" appear in their names without prior written 85 * permission of the OpenSSL Project. 86 * 87 * 6. Redistributions of any form whatsoever must retain the following 88 * acknowledgment: 89 * "This product includes software developed by the OpenSSL Project 90 * for use in the OpenSSL Toolkit (http://www.openssl.org/)" 91 * 92 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY 93 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 94 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 95 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR 96 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 97 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 98 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 99 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 100 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 101 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 102 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 103 * OF THE POSSIBILITY OF SUCH DAMAGE. 104 * ==================================================================== 105 * 106 * This product includes cryptographic software written by Eric Young 107 * (eay@cryptsoft.com). This product includes software written by Tim 108 * Hudson (tjh@cryptsoft.com). 109 * 110 */ 111 112#include <errno.h> 113#include <limits.h> 114#include <stdio.h> 115 116#include <openssl/buffer.h> 117#include <openssl/evp.h> 118 119#include "bytestring.h" 120#include "dtls_local.h" 121#include "ssl_local.h" 122#include "tls_content.h" 123 124static int do_ssl3_write(SSL *s, int type, const unsigned char *buf, 125 unsigned int len); 126static int ssl3_get_record(SSL *s); 127 128/* 129 * Force a WANT_READ return for certain error conditions where 130 * we don't want to spin internally. 131 */ 132void 133ssl_force_want_read(SSL *s) 134{ 135 BIO *bio; 136 137 bio = SSL_get_rbio(s); 138 BIO_clear_retry_flags(bio); 139 BIO_set_retry_read(bio); 140 141 s->rwstate = SSL_READING; 142} 143 144/* 145 * If extend == 0, obtain new n-byte packet; if extend == 1, increase 146 * packet by another n bytes. 147 * The packet will be in the sub-array of s->s3->rbuf.buf specified 148 * by s->packet and s->packet_length. 149 * (If s->read_ahead is set, 'max' bytes may be stored in rbuf 150 * [plus s->packet_length bytes if extend == 1].) 151 */ 152static int 153ssl3_read_n(SSL *s, int n, int max, int extend) 154{ 155 SSL3_BUFFER_INTERNAL *rb = &(s->s3->rbuf); 156 int i, len, left; 157 size_t align; 158 unsigned char *pkt; 159 160 if (n <= 0) 161 return n; 162 163 if (rb->buf == NULL) { 164 if (!ssl3_setup_read_buffer(s)) 165 return -1; 166 } 167 if (rb->buf == NULL) 168 return -1; 169 170 left = rb->left; 171 align = (size_t)rb->buf + SSL3_RT_HEADER_LENGTH; 172 align = (-align) & (SSL3_ALIGN_PAYLOAD - 1); 173 174 if (!extend) { 175 /* start with empty packet ... */ 176 if (left == 0) 177 rb->offset = align; 178 else if (align != 0 && left >= SSL3_RT_HEADER_LENGTH) { 179 /* check if next packet length is large 180 * enough to justify payload alignment... */ 181 pkt = rb->buf + rb->offset; 182 if (pkt[0] == SSL3_RT_APPLICATION_DATA && 183 (pkt[3]<<8|pkt[4]) >= 128) { 184 /* Note that even if packet is corrupted 185 * and its length field is insane, we can 186 * only be led to wrong decision about 187 * whether memmove will occur or not. 188 * Header values has no effect on memmove 189 * arguments and therefore no buffer 190 * overrun can be triggered. */ 191 memmove(rb->buf + align, pkt, left); 192 rb->offset = align; 193 } 194 } 195 s->packet = rb->buf + rb->offset; 196 s->packet_length = 0; 197 /* ... now we can act as if 'extend' was set */ 198 } 199 200 /* For DTLS/UDP reads should not span multiple packets 201 * because the read operation returns the whole packet 202 * at once (as long as it fits into the buffer). */ 203 if (SSL_is_dtls(s)) { 204 if (left > 0 && n > left) 205 n = left; 206 } 207 208 /* if there is enough in the buffer from a previous read, take some */ 209 if (left >= n) { 210 s->packet_length += n; 211 rb->left = left - n; 212 rb->offset += n; 213 return (n); 214 } 215 216 /* else we need to read more data */ 217 218 len = s->packet_length; 219 pkt = rb->buf + align; 220 /* Move any available bytes to front of buffer: 221 * 'len' bytes already pointed to by 'packet', 222 * 'left' extra ones at the end */ 223 if (s->packet != pkt) { 224 /* len > 0 */ 225 memmove(pkt, s->packet, len + left); 226 s->packet = pkt; 227 rb->offset = len + align; 228 } 229 230 if (n > (int)(rb->len - rb->offset)) { 231 /* does not happen */ 232 SSLerror(s, ERR_R_INTERNAL_ERROR); 233 return -1; 234 } 235 236 if (s->read_ahead || SSL_is_dtls(s)) { 237 if (max < n) 238 max = n; 239 if (max > (int)(rb->len - rb->offset)) 240 max = rb->len - rb->offset; 241 } else { 242 /* ignore max parameter */ 243 max = n; 244 } 245 246 while (left < n) { 247 /* Now we have len+left bytes at the front of s->s3->rbuf.buf 248 * and need to read in more until we have len+n (up to 249 * len+max if possible) */ 250 251 errno = 0; 252 if (s->rbio != NULL) { 253 s->rwstate = SSL_READING; 254 i = BIO_read(s->rbio, pkt + len + left, max - left); 255 } else { 256 SSLerror(s, SSL_R_READ_BIO_NOT_SET); 257 i = -1; 258 } 259 260 if (i <= 0) { 261 rb->left = left; 262 if (s->mode & SSL_MODE_RELEASE_BUFFERS && 263 !SSL_is_dtls(s)) { 264 if (len + left == 0) 265 ssl3_release_read_buffer(s); 266 } 267 return (i); 268 } 269 left += i; 270 271 /* 272 * reads should *never* span multiple packets for DTLS because 273 * the underlying transport protocol is message oriented as 274 * opposed to byte oriented as in the TLS case. 275 */ 276 if (SSL_is_dtls(s)) { 277 if (n > left) 278 n = left; /* makes the while condition false */ 279 } 280 } 281 282 /* done reading, now the book-keeping */ 283 rb->offset += n; 284 rb->left = left - n; 285 s->packet_length += n; 286 s->rwstate = SSL_NOTHING; 287 288 return (n); 289} 290 291int 292ssl3_packet_read(SSL *s, int plen) 293{ 294 int n; 295 296 n = ssl3_read_n(s, plen, s->s3->rbuf.len, 0); 297 if (n <= 0) 298 return n; 299 if (s->packet_length < plen) 300 return s->packet_length; 301 302 return plen; 303} 304 305int 306ssl3_packet_extend(SSL *s, int plen) 307{ 308 int rlen, n; 309 310 if (s->packet_length >= plen) 311 return plen; 312 rlen = plen - s->packet_length; 313 314 n = ssl3_read_n(s, rlen, rlen, 1); 315 if (n <= 0) 316 return n; 317 if (s->packet_length < plen) 318 return s->packet_length; 319 320 return plen; 321} 322 323/* Call this to get a new input record. 324 * It will return <= 0 if more data is needed, normally due to an error 325 * or non-blocking IO. 326 * When it finishes, one packet has been decoded and can be found in 327 * ssl->s3->rrec.type - is the type of record 328 * ssl->s3->rrec.data, - data 329 * ssl->s3->rrec.length, - number of bytes 330 */ 331/* used only by ssl3_read_bytes */ 332static int 333ssl3_get_record(SSL *s) 334{ 335 SSL3_BUFFER_INTERNAL *rb = &(s->s3->rbuf); 336 SSL3_RECORD_INTERNAL *rr = &(s->s3->rrec); 337 uint8_t alert_desc; 338 int al, n; 339 int ret = -1; 340 341 again: 342 /* check if we have the header */ 343 if ((s->rstate != SSL_ST_READ_BODY) || 344 (s->packet_length < SSL3_RT_HEADER_LENGTH)) { 345 CBS header; 346 uint16_t len, ssl_version; 347 uint8_t type; 348 349 n = ssl3_packet_read(s, SSL3_RT_HEADER_LENGTH); 350 if (n <= 0) 351 return (n); 352 353 s->mac_packet = 1; 354 s->rstate = SSL_ST_READ_BODY; 355 356 if (s->server && s->first_packet) { 357 if ((ret = ssl_server_legacy_first_packet(s)) != 1) 358 return (ret); 359 ret = -1; 360 } 361 362 CBS_init(&header, s->packet, SSL3_RT_HEADER_LENGTH); 363 364 /* Pull apart the header into the SSL3_RECORD_INTERNAL */ 365 if (!CBS_get_u8(&header, &type) || 366 !CBS_get_u16(&header, &ssl_version) || 367 !CBS_get_u16(&header, &len)) { 368 SSLerror(s, SSL_R_BAD_PACKET_LENGTH); 369 goto err; 370 } 371 372 rr->type = type; 373 rr->length = len; 374 375 /* Lets check version */ 376 if (!s->first_packet && ssl_version != s->version) { 377 if ((s->version & 0xFF00) == (ssl_version & 0xFF00) && 378 !tls12_record_layer_write_protected(s->rl)) { 379 /* Send back error using their minor version number :-) */ 380 s->version = ssl_version; 381 } 382 SSLerror(s, SSL_R_WRONG_VERSION_NUMBER); 383 al = SSL_AD_PROTOCOL_VERSION; 384 goto fatal_err; 385 } 386 387 if ((ssl_version >> 8) != SSL3_VERSION_MAJOR) { 388 SSLerror(s, SSL_R_WRONG_VERSION_NUMBER); 389 goto err; 390 } 391 392 if (rr->length > rb->len - SSL3_RT_HEADER_LENGTH) { 393 al = SSL_AD_RECORD_OVERFLOW; 394 SSLerror(s, SSL_R_PACKET_LENGTH_TOO_LONG); 395 goto fatal_err; 396 } 397 } 398 399 n = ssl3_packet_extend(s, SSL3_RT_HEADER_LENGTH + rr->length); 400 if (n <= 0) 401 return (n); 402 if (n != SSL3_RT_HEADER_LENGTH + rr->length) 403 return (n); 404 405 s->rstate = SSL_ST_READ_HEADER; /* set state for later operations */ 406 407 /* 408 * A full record has now been read from the wire, which now needs 409 * to be processed. 410 */ 411 tls12_record_layer_set_version(s->rl, s->version); 412 413 if (!tls12_record_layer_open_record(s->rl, s->packet, s->packet_length, 414 s->s3->rcontent)) { 415 tls12_record_layer_alert(s->rl, &alert_desc); 416 417 if (alert_desc == 0) 418 goto err; 419 420 if (alert_desc == SSL_AD_RECORD_OVERFLOW) 421 SSLerror(s, SSL_R_ENCRYPTED_LENGTH_TOO_LONG); 422 else if (alert_desc == SSL_AD_BAD_RECORD_MAC) 423 SSLerror(s, SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC); 424 425 al = alert_desc; 426 goto fatal_err; 427 } 428 429 /* we have pulled in a full packet so zero things */ 430 s->packet_length = 0; 431 432 if (tls_content_remaining(s->s3->rcontent) == 0) { 433 /* 434 * Zero-length fragments are only permitted for application 435 * data, as per RFC 5246 section 6.2.1. 436 */ 437 if (rr->type != SSL3_RT_APPLICATION_DATA) { 438 SSLerror(s, SSL_R_BAD_LENGTH); 439 al = SSL_AD_UNEXPECTED_MESSAGE; 440 goto fatal_err; 441 } 442 443 tls_content_clear(s->s3->rcontent); 444 445 /* 446 * CBC countermeasures for known IV weaknesses can legitimately 447 * insert a single empty record, so we allow ourselves to read 448 * once past a single empty record without forcing want_read. 449 */ 450 if (s->empty_record_count++ > SSL_MAX_EMPTY_RECORDS) { 451 SSLerror(s, SSL_R_PEER_BEHAVING_BADLY); 452 return -1; 453 } 454 if (s->empty_record_count > 1) { 455 ssl_force_want_read(s); 456 return -1; 457 } 458 goto again; 459 } 460 461 s->empty_record_count = 0; 462 463 return (1); 464 465 fatal_err: 466 ssl3_send_alert(s, SSL3_AL_FATAL, al); 467 err: 468 return (ret); 469} 470 471/* Call this to write data in records of type 'type' 472 * It will return <= 0 if not all data has been sent or non-blocking IO. 473 */ 474int 475ssl3_write_bytes(SSL *s, int type, const void *buf_, int len) 476{ 477 const unsigned char *buf = buf_; 478 unsigned int tot, n, nw; 479 int i; 480 481 if (len < 0) { 482 SSLerror(s, ERR_R_INTERNAL_ERROR); 483 return -1; 484 } 485 486 s->rwstate = SSL_NOTHING; 487 tot = s->s3->wnum; 488 s->s3->wnum = 0; 489 490 if (SSL_in_init(s) && !s->in_handshake) { 491 i = s->handshake_func(s); 492 if (i < 0) 493 return (i); 494 if (i == 0) { 495 SSLerror(s, SSL_R_SSL_HANDSHAKE_FAILURE); 496 return -1; 497 } 498 } 499 500 if (len < tot) 501 len = tot; 502 n = (len - tot); 503 for (;;) { 504 if (n > s->max_send_fragment) 505 nw = s->max_send_fragment; 506 else 507 nw = n; 508 509 i = do_ssl3_write(s, type, &(buf[tot]), nw); 510 if (i <= 0) { 511 s->s3->wnum = tot; 512 return i; 513 } 514 515 if ((i == (int)n) || (type == SSL3_RT_APPLICATION_DATA && 516 (s->mode & SSL_MODE_ENABLE_PARTIAL_WRITE))) { 517 /* 518 * Next chunk of data should get another prepended 519 * empty fragment in ciphersuites with known-IV 520 * weakness. 521 */ 522 s->s3->empty_fragment_done = 0; 523 524 return tot + i; 525 } 526 527 n -= i; 528 tot += i; 529 } 530} 531 532static int 533do_ssl3_write(SSL *s, int type, const unsigned char *buf, unsigned int len) 534{ 535 SSL3_BUFFER_INTERNAL *wb = &(s->s3->wbuf); 536 SSL_SESSION *sess = s->session; 537 int need_empty_fragment = 0; 538 size_t align, out_len; 539 CBB cbb; 540 int ret; 541 542 memset(&cbb, 0, sizeof(cbb)); 543 544 if (wb->buf == NULL) 545 if (!ssl3_setup_write_buffer(s)) 546 return -1; 547 548 /* 549 * First check if there is a SSL3_BUFFER_INTERNAL still being written 550 * out. This will happen with non blocking IO. 551 */ 552 if (wb->left != 0) 553 return (ssl3_write_pending(s, type, buf, len)); 554 555 /* If we have an alert to send, let's send it. */ 556 if (s->s3->alert_dispatch) { 557 if ((ret = ssl3_dispatch_alert(s)) <= 0) 558 return (ret); 559 /* If it went, fall through and send more stuff. */ 560 561 /* We may have released our buffer, if so get it again. */ 562 if (wb->buf == NULL) 563 if (!ssl3_setup_write_buffer(s)) 564 return -1; 565 } 566 567 if (len == 0) 568 return 0; 569 570 /* 571 * Countermeasure against known-IV weakness in CBC ciphersuites 572 * (see http://www.openssl.org/~bodo/tls-cbc.txt). Note that this 573 * is unnecessary for AEAD. 574 */ 575 if (sess != NULL && tls12_record_layer_write_protected(s->rl)) { 576 if (s->s3->need_empty_fragments && 577 !s->s3->empty_fragment_done && 578 type == SSL3_RT_APPLICATION_DATA) 579 need_empty_fragment = 1; 580 } 581 582 /* 583 * An extra fragment would be a couple of cipher blocks, which would 584 * be a multiple of SSL3_ALIGN_PAYLOAD, so if we want to align the real 585 * payload, then we can just simply pretend we have two headers. 586 */ 587 align = (size_t)wb->buf + SSL3_RT_HEADER_LENGTH; 588 if (need_empty_fragment) 589 align += SSL3_RT_HEADER_LENGTH; 590 align = (-align) & (SSL3_ALIGN_PAYLOAD - 1); 591 wb->offset = align; 592 593 if (!CBB_init_fixed(&cbb, wb->buf + align, wb->len - align)) 594 goto err; 595 596 tls12_record_layer_set_version(s->rl, s->version); 597 598 if (need_empty_fragment) { 599 if (!tls12_record_layer_seal_record(s->rl, type, 600 buf, 0, &cbb)) 601 goto err; 602 s->s3->empty_fragment_done = 1; 603 } 604 605 if (!tls12_record_layer_seal_record(s->rl, type, buf, len, &cbb)) 606 goto err; 607 608 if (!CBB_finish(&cbb, NULL, &out_len)) 609 goto err; 610 611 wb->left = out_len; 612 613 /* 614 * Memorize arguments so that ssl3_write_pending can detect 615 * bad write retries later. 616 */ 617 s->s3->wpend_tot = len; 618 s->s3->wpend_buf = buf; 619 s->s3->wpend_type = type; 620 s->s3->wpend_ret = len; 621 622 /* We now just need to write the buffer. */ 623 return ssl3_write_pending(s, type, buf, len); 624 625 err: 626 CBB_cleanup(&cbb); 627 628 return -1; 629} 630 631/* if s->s3->wbuf.left != 0, we need to call this */ 632int 633ssl3_write_pending(SSL *s, int type, const unsigned char *buf, unsigned int len) 634{ 635 int i; 636 SSL3_BUFFER_INTERNAL *wb = &(s->s3->wbuf); 637 638 /* XXXX */ 639 if ((s->s3->wpend_tot > (int)len) || ((s->s3->wpend_buf != buf) && 640 !(s->mode & SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER)) || 641 (s->s3->wpend_type != type)) { 642 SSLerror(s, SSL_R_BAD_WRITE_RETRY); 643 return (-1); 644 } 645 646 for (;;) { 647 errno = 0; 648 if (s->wbio != NULL) { 649 s->rwstate = SSL_WRITING; 650 i = BIO_write(s->wbio, (char *)&(wb->buf[wb->offset]), 651 (unsigned int)wb->left); 652 } else { 653 SSLerror(s, SSL_R_BIO_NOT_SET); 654 i = -1; 655 } 656 if (i == wb->left) { 657 wb->left = 0; 658 wb->offset += i; 659 if (s->mode & SSL_MODE_RELEASE_BUFFERS && 660 !SSL_is_dtls(s)) 661 ssl3_release_write_buffer(s); 662 s->rwstate = SSL_NOTHING; 663 return (s->s3->wpend_ret); 664 } else if (i <= 0) { 665 /* 666 * For DTLS, just drop it. That's kind of the 667 * whole point in using a datagram service. 668 */ 669 if (SSL_is_dtls(s)) 670 wb->left = 0; 671 return (i); 672 } 673 wb->offset += i; 674 wb->left -= i; 675 } 676} 677 678static ssize_t 679ssl3_read_cb(void *buf, size_t n, void *cb_arg) 680{ 681 SSL *s = cb_arg; 682 683 return tls_content_read(s->s3->rcontent, buf, n); 684} 685 686#define SSL3_ALERT_LENGTH 2 687 688int 689ssl3_read_alert(SSL *s) 690{ 691 uint8_t alert_level, alert_descr; 692 ssize_t ret; 693 CBS cbs; 694 695 /* 696 * TLSv1.2 permits an alert to be fragmented across multiple records or 697 * for multiple alerts to be be coalesced into a single alert record. 698 * In the case of DTLS, there is no way to reassemble an alert 699 * fragmented across multiple records, hence a full alert must be 700 * available in the record. 701 */ 702 if (s->s3->alert_fragment == NULL) { 703 if ((s->s3->alert_fragment = tls_buffer_new(0)) == NULL) 704 return -1; 705 tls_buffer_set_capacity_limit(s->s3->alert_fragment, 706 SSL3_ALERT_LENGTH); 707 } 708 ret = tls_buffer_extend(s->s3->alert_fragment, SSL3_ALERT_LENGTH, 709 ssl3_read_cb, s); 710 if (ret <= 0 && ret != TLS_IO_WANT_POLLIN) 711 return -1; 712 if (ret != SSL3_ALERT_LENGTH) { 713 if (SSL_is_dtls(s)) { 714 SSLerror(s, SSL_R_BAD_LENGTH); 715 ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); 716 return -1; 717 } 718 return 1; 719 } 720 721 if (!tls_buffer_data(s->s3->alert_fragment, &cbs)) 722 return -1; 723 724 ssl_msg_callback_cbs(s, 0, SSL3_RT_ALERT, &cbs); 725 726 if (!CBS_get_u8(&cbs, &alert_level)) 727 return -1; 728 if (!CBS_get_u8(&cbs, &alert_descr)) 729 return -1; 730 731 tls_buffer_free(s->s3->alert_fragment); 732 s->s3->alert_fragment = NULL; 733 734 ssl_info_callback(s, SSL_CB_READ_ALERT, 735 (alert_level << 8) | alert_descr); 736 737 if (alert_level == SSL3_AL_WARNING) { 738 s->s3->warn_alert = alert_descr; 739 if (alert_descr == SSL_AD_CLOSE_NOTIFY) { 740 s->shutdown |= SSL_RECEIVED_SHUTDOWN; 741 return 0; 742 } 743 /* We requested renegotiation and the peer rejected it. */ 744 if (alert_descr == SSL_AD_NO_RENEGOTIATION) { 745 SSLerror(s, SSL_R_NO_RENEGOTIATION); 746 ssl3_send_alert(s, SSL3_AL_FATAL, 747 SSL_AD_HANDSHAKE_FAILURE); 748 return -1; 749 } 750 } else if (alert_level == SSL3_AL_FATAL) { 751 s->rwstate = SSL_NOTHING; 752 s->s3->fatal_alert = alert_descr; 753 SSLerror(s, SSL_AD_REASON_OFFSET + alert_descr); 754 ERR_asprintf_error_data("SSL alert number %d", alert_descr); 755 s->shutdown |= SSL_RECEIVED_SHUTDOWN; 756 SSL_CTX_remove_session(s->ctx, s->session); 757 return 0; 758 } else { 759 SSLerror(s, SSL_R_UNKNOWN_ALERT_TYPE); 760 ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); 761 return -1; 762 } 763 764 return 1; 765} 766 767int 768ssl3_read_change_cipher_spec(SSL *s) 769{ 770 const uint8_t ccs[1] = { SSL3_MT_CCS }; 771 772 /* 773 * 'Change Cipher Spec' is just a single byte, so we know exactly what 774 * the record payload has to look like. 775 */ 776 if (tls_content_remaining(s->s3->rcontent) != sizeof(ccs)) { 777 SSLerror(s, SSL_R_BAD_CHANGE_CIPHER_SPEC); 778 ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); 779 return -1; 780 } 781 if (!tls_content_equal(s->s3->rcontent, ccs, sizeof(ccs))) { 782 SSLerror(s, SSL_R_BAD_CHANGE_CIPHER_SPEC); 783 ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_ILLEGAL_PARAMETER); 784 return -1; 785 } 786 787 /* XDTLS: check that epoch is consistent */ 788 789 ssl_msg_callback_cbs(s, 0, SSL3_RT_CHANGE_CIPHER_SPEC, 790 tls_content_cbs(s->s3->rcontent)); 791 792 /* Check that we have a cipher to change to. */ 793 if (s->s3->hs.cipher == NULL) { 794 SSLerror(s, SSL_R_CCS_RECEIVED_EARLY); 795 ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE); 796 return -1; 797 } 798 799 /* Check that we should be receiving a Change Cipher Spec. */ 800 if (SSL_is_dtls(s)) { 801 if (!s->d1->change_cipher_spec_ok) { 802 /* 803 * We can't process a CCS now, because previous 804 * handshake messages are still missing, so just 805 * drop it. 806 */ 807 tls_content_clear(s->s3->rcontent); 808 return 1; 809 } 810 s->d1->change_cipher_spec_ok = 0; 811 } else { 812 if ((s->s3->flags & SSL3_FLAGS_CCS_OK) == 0) { 813 SSLerror(s, SSL_R_CCS_RECEIVED_EARLY); 814 ssl3_send_alert(s, SSL3_AL_FATAL, 815 SSL_AD_UNEXPECTED_MESSAGE); 816 return -1; 817 } 818 s->s3->flags &= ~SSL3_FLAGS_CCS_OK; 819 } 820 821 tls_content_clear(s->s3->rcontent); 822 823 s->s3->change_cipher_spec = 1; 824 if (!ssl3_do_change_cipher_spec(s)) 825 return -1; 826 827 return 1; 828} 829 830static int 831ssl3_read_handshake_unexpected(SSL *s) 832{ 833 uint32_t hs_msg_length; 834 uint8_t hs_msg_type; 835 ssize_t ssret; 836 CBS cbs; 837 int ret; 838 839 /* 840 * We need four bytes of handshake data so we have a handshake message 841 * header - this may be in the same record or fragmented across multiple 842 * records. 843 */ 844 if (s->s3->handshake_fragment == NULL) { 845 if ((s->s3->handshake_fragment = tls_buffer_new(0)) == NULL) 846 return -1; 847 tls_buffer_set_capacity_limit(s->s3->handshake_fragment, 848 SSL3_HM_HEADER_LENGTH); 849 } 850 ssret = tls_buffer_extend(s->s3->handshake_fragment, SSL3_HM_HEADER_LENGTH, 851 ssl3_read_cb, s); 852 if (ssret <= 0 && ssret != TLS_IO_WANT_POLLIN) 853 return -1; 854 if (ssret != SSL3_HM_HEADER_LENGTH) 855 return 1; 856 857 if (s->in_handshake) { 858 SSLerror(s, ERR_R_INTERNAL_ERROR); 859 return -1; 860 } 861 862 /* 863 * This code currently deals with HelloRequest and ClientHello messages - 864 * anything else is pushed to the handshake_func. Almost all of this 865 * belongs in the client/server handshake code. 866 */ 867 868 /* Parse handshake message header. */ 869 if (!tls_buffer_data(s->s3->handshake_fragment, &cbs)) 870 return -1; 871 if (!CBS_get_u8(&cbs, &hs_msg_type)) 872 return -1; 873 if (!CBS_get_u24(&cbs, &hs_msg_length)) 874 return -1; 875 876 if (hs_msg_type == SSL3_MT_HELLO_REQUEST) { 877 /* 878 * Incoming HelloRequest messages should only be received by a 879 * client. A server may send these at any time - a client should 880 * ignore the message if received in the middle of a handshake. 881 * See RFC 5246 sections 7.4 and 7.4.1.1. 882 */ 883 if (s->server) { 884 SSLerror(s, SSL_R_UNEXPECTED_MESSAGE); 885 ssl3_send_alert(s, SSL3_AL_FATAL, 886 SSL_AD_UNEXPECTED_MESSAGE); 887 return -1; 888 } 889 890 if (hs_msg_length != 0) { 891 SSLerror(s, SSL_R_BAD_HELLO_REQUEST); 892 ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR); 893 return -1; 894 } 895 896 if (!tls_buffer_data(s->s3->handshake_fragment, &cbs)) 897 return -1; 898 ssl_msg_callback_cbs(s, 0, SSL3_RT_HANDSHAKE, &cbs); 899 900 tls_buffer_free(s->s3->handshake_fragment); 901 s->s3->handshake_fragment = NULL; 902 903 /* 904 * It should be impossible to hit this, but keep the safety 905 * harness for now... 906 */ 907 if (s->session == NULL || s->session->cipher == NULL) 908 return 1; 909 910 /* 911 * Ignore this message if we're currently handshaking, 912 * renegotiation is already pending or renegotiation is disabled 913 * via flags. 914 */ 915 if (!SSL_is_init_finished(s) || s->s3->renegotiate || 916 (s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS) != 0) 917 return 1; 918 919 if (!ssl3_renegotiate(s)) 920 return 1; 921 if (!ssl3_renegotiate_check(s)) 922 return 1; 923 924 } else if (hs_msg_type == SSL3_MT_CLIENT_HELLO) { 925 /* 926 * Incoming ClientHello messages should only be received by a 927 * server. A client may send these in response to server 928 * initiated renegotiation (HelloRequest) or in order to 929 * initiate renegotiation by the client. See RFC 5246 section 930 * 7.4.1.2. 931 */ 932 if (!s->server) { 933 SSLerror(s, SSL_R_UNEXPECTED_MESSAGE); 934 ssl3_send_alert(s, SSL3_AL_FATAL, 935 SSL_AD_UNEXPECTED_MESSAGE); 936 return -1; 937 } 938 939 /* 940 * A client should not be sending a ClientHello unless we're not 941 * currently handshaking. 942 */ 943 if (!SSL_is_init_finished(s)) { 944 SSLerror(s, SSL_R_UNEXPECTED_MESSAGE); 945 ssl3_send_alert(s, SSL3_AL_FATAL, 946 SSL_AD_UNEXPECTED_MESSAGE); 947 return -1; 948 } 949 950 if ((s->options & SSL_OP_NO_CLIENT_RENEGOTIATION) != 0) { 951 ssl3_send_alert(s, SSL3_AL_FATAL, 952 SSL_AD_NO_RENEGOTIATION); 953 return -1; 954 } 955 956 if (s->session == NULL || s->session->cipher == NULL) { 957 SSLerror(s, ERR_R_INTERNAL_ERROR); 958 return -1; 959 } 960 961 /* Client requested renegotiation but it is not permitted. */ 962 if (!s->s3->send_connection_binding || 963 (s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS) != 0) { 964 ssl3_send_alert(s, SSL3_AL_WARNING, 965 SSL_AD_NO_RENEGOTIATION); 966 return 1; 967 } 968 969 s->s3->hs.state = SSL_ST_ACCEPT; 970 s->renegotiate = 1; 971 s->new_session = 1; 972 973 } else { 974 SSLerror(s, SSL_R_UNEXPECTED_MESSAGE); 975 ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE); 976 return -1; 977 } 978 979 if ((ret = s->handshake_func(s)) < 0) 980 return ret; 981 if (ret == 0) { 982 SSLerror(s, SSL_R_SSL_HANDSHAKE_FAILURE); 983 return -1; 984 } 985 986 if (!(s->mode & SSL_MODE_AUTO_RETRY)) { 987 if (s->s3->rbuf.left == 0) { 988 ssl_force_want_read(s); 989 return -1; 990 } 991 } 992 993 /* 994 * We either finished a handshake or ignored the request, now try again 995 * to obtain the (application) data we were asked for. 996 */ 997 return 1; 998} 999 1000/* Return up to 'len' payload bytes received in 'type' records. 1001 * 'type' is one of the following: 1002 * 1003 * - SSL3_RT_HANDSHAKE (when ssl3_get_message calls us) 1004 * - SSL3_RT_APPLICATION_DATA (when ssl3_read calls us) 1005 * - 0 (during a shutdown, no data has to be returned) 1006 * 1007 * If we don't have stored data to work from, read a SSL/TLS record first 1008 * (possibly multiple records if we still don't have anything to return). 1009 * 1010 * This function must handle any surprises the peer may have for us, such as 1011 * Alert records (e.g. close_notify), ChangeCipherSpec records (not really 1012 * a surprise, but handled as if it were), or renegotiation requests. 1013 * Also if record payloads contain fragments too small to process, we store 1014 * them until there is enough for the respective protocol (the record protocol 1015 * may use arbitrary fragmentation and even interleaving): 1016 * Change cipher spec protocol 1017 * just 1 byte needed, no need for keeping anything stored 1018 * Alert protocol 1019 * 2 bytes needed (AlertLevel, AlertDescription) 1020 * Handshake protocol 1021 * 4 bytes needed (HandshakeType, uint24 length) -- we just have 1022 * to detect unexpected Client Hello and Hello Request messages 1023 * here, anything else is handled by higher layers 1024 * Application data protocol 1025 * none of our business 1026 */ 1027int 1028ssl3_read_bytes(SSL *s, int type, unsigned char *buf, int len, int peek) 1029{ 1030 int rrcount = 0; 1031 ssize_t ssret; 1032 int ret; 1033 1034 if (s->s3->rbuf.buf == NULL) { 1035 if (!ssl3_setup_read_buffer(s)) 1036 return -1; 1037 } 1038 1039 if (s->s3->rcontent == NULL) { 1040 if ((s->s3->rcontent = tls_content_new()) == NULL) 1041 return -1; 1042 } 1043 1044 if (len < 0) { 1045 SSLerror(s, ERR_R_INTERNAL_ERROR); 1046 return -1; 1047 } 1048 1049 if (type != 0 && type != SSL3_RT_APPLICATION_DATA && 1050 type != SSL3_RT_HANDSHAKE) { 1051 SSLerror(s, ERR_R_INTERNAL_ERROR); 1052 return -1; 1053 } 1054 if (peek && type != SSL3_RT_APPLICATION_DATA) { 1055 SSLerror(s, ERR_R_INTERNAL_ERROR); 1056 return -1; 1057 } 1058 1059 if (type == SSL3_RT_HANDSHAKE && 1060 s->s3->handshake_fragment != NULL && 1061 tls_buffer_remaining(s->s3->handshake_fragment) > 0) { 1062 ssize_t ssn; 1063 1064 if ((ssn = tls_buffer_read(s->s3->handshake_fragment, buf, 1065 len)) <= 0) 1066 return -1; 1067 1068 if (tls_buffer_remaining(s->s3->handshake_fragment) == 0) { 1069 tls_buffer_free(s->s3->handshake_fragment); 1070 s->s3->handshake_fragment = NULL; 1071 } 1072 1073 return (int)ssn; 1074 } 1075 1076 if (SSL_in_init(s) && !s->in_handshake) { 1077 if ((ret = s->handshake_func(s)) < 0) 1078 return ret; 1079 if (ret == 0) { 1080 SSLerror(s, SSL_R_SSL_HANDSHAKE_FAILURE); 1081 return -1; 1082 } 1083 } 1084 1085 start: 1086 /* 1087 * Do not process more than three consecutive records, otherwise the 1088 * peer can cause us to loop indefinitely. Instead, return with an 1089 * SSL_ERROR_WANT_READ so the caller can choose when to handle further 1090 * processing. In the future, the total number of non-handshake and 1091 * non-application data records per connection should probably also be 1092 * limited... 1093 */ 1094 if (rrcount++ >= 3) { 1095 ssl_force_want_read(s); 1096 return -1; 1097 } 1098 1099 s->rwstate = SSL_NOTHING; 1100 1101 if (tls_content_remaining(s->s3->rcontent) == 0) { 1102 if ((ret = ssl3_get_record(s)) <= 0) 1103 return ret; 1104 } 1105 1106 /* We now have a packet which can be read and processed. */ 1107 1108 if (s->s3->change_cipher_spec && 1109 tls_content_type(s->s3->rcontent) != SSL3_RT_HANDSHAKE) { 1110 SSLerror(s, SSL_R_DATA_BETWEEN_CCS_AND_FINISHED); 1111 ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE); 1112 return -1; 1113 } 1114 1115 /* 1116 * If the other end has shut down, throw anything we read away (even in 1117 * 'peek' mode). 1118 */ 1119 if (s->shutdown & SSL_RECEIVED_SHUTDOWN) { 1120 s->rwstate = SSL_NOTHING; 1121 tls_content_clear(s->s3->rcontent); 1122 s->s3->rrec.length = 0; 1123 return 0; 1124 } 1125 1126 /* SSL3_RT_APPLICATION_DATA or SSL3_RT_HANDSHAKE */ 1127 if (tls_content_type(s->s3->rcontent) == type) { 1128 /* 1129 * Make sure that we are not getting application data when we 1130 * are doing a handshake for the first time. 1131 */ 1132 if (SSL_in_init(s) && type == SSL3_RT_APPLICATION_DATA && 1133 !tls12_record_layer_read_protected(s->rl)) { 1134 SSLerror(s, SSL_R_APP_DATA_IN_HANDSHAKE); 1135 ssl3_send_alert(s, SSL3_AL_FATAL, 1136 SSL_AD_UNEXPECTED_MESSAGE); 1137 return -1; 1138 } 1139 1140 if (len <= 0) 1141 return len; 1142 1143 if (peek) { 1144 ssret = tls_content_peek(s->s3->rcontent, buf, len); 1145 } else { 1146 ssret = tls_content_read(s->s3->rcontent, buf, len); 1147 } 1148 if (ssret < INT_MIN || ssret > INT_MAX) 1149 return -1; 1150 if (ssret < 0) 1151 return (int)ssret; 1152 1153 if (tls_content_remaining(s->s3->rcontent) == 0) { 1154 s->rstate = SSL_ST_READ_HEADER; 1155 1156 if (s->mode & SSL_MODE_RELEASE_BUFFERS && 1157 s->s3->rbuf.left == 0) 1158 ssl3_release_read_buffer(s); 1159 } 1160 1161 return ssret; 1162 } 1163 1164 if (tls_content_type(s->s3->rcontent) == SSL3_RT_ALERT) { 1165 if ((ret = ssl3_read_alert(s)) <= 0) 1166 return ret; 1167 goto start; 1168 } 1169 1170 if (s->shutdown & SSL_SENT_SHUTDOWN) { 1171 s->rwstate = SSL_NOTHING; 1172 tls_content_clear(s->s3->rcontent); 1173 s->s3->rrec.length = 0; 1174 return 0; 1175 } 1176 1177 if (tls_content_type(s->s3->rcontent) == SSL3_RT_APPLICATION_DATA) { 1178 /* 1179 * At this point, we were expecting handshake data, but have 1180 * application data. If the library was running inside 1181 * ssl3_read() (i.e. in_read_app_data is set) and it makes 1182 * sense to read application data at this point (session 1183 * renegotiation not yet started), we will indulge it. 1184 */ 1185 if (s->s3->in_read_app_data != 0 && 1186 s->s3->total_renegotiations != 0 && 1187 (((s->s3->hs.state & SSL_ST_CONNECT) && 1188 (s->s3->hs.state >= SSL3_ST_CW_CLNT_HELLO_A) && 1189 (s->s3->hs.state <= SSL3_ST_CR_SRVR_HELLO_A)) || ( 1190 (s->s3->hs.state & SSL_ST_ACCEPT) && 1191 (s->s3->hs.state <= SSL3_ST_SW_HELLO_REQ_A) && 1192 (s->s3->hs.state >= SSL3_ST_SR_CLNT_HELLO_A)))) { 1193 s->s3->in_read_app_data = 2; 1194 return -1; 1195 } else { 1196 SSLerror(s, SSL_R_UNEXPECTED_RECORD); 1197 ssl3_send_alert(s, SSL3_AL_FATAL, 1198 SSL_AD_UNEXPECTED_MESSAGE); 1199 return -1; 1200 } 1201 } 1202 1203 if (tls_content_type(s->s3->rcontent) == SSL3_RT_CHANGE_CIPHER_SPEC) { 1204 if ((ret = ssl3_read_change_cipher_spec(s)) <= 0) 1205 return ret; 1206 goto start; 1207 } 1208 1209 if (tls_content_type(s->s3->rcontent) == SSL3_RT_HANDSHAKE) { 1210 if ((ret = ssl3_read_handshake_unexpected(s)) <= 0) 1211 return ret; 1212 goto start; 1213 } 1214 1215 /* 1216 * Unknown record type - TLSv1.2 sends an unexpected message alert while 1217 * earlier versions silently ignore the record. 1218 */ 1219 if (ssl_effective_tls_version(s) <= TLS1_1_VERSION) { 1220 tls_content_clear(s->s3->rcontent); 1221 goto start; 1222 } 1223 SSLerror(s, SSL_R_UNEXPECTED_RECORD); 1224 ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_UNEXPECTED_MESSAGE); 1225 return -1; 1226} 1227 1228int 1229ssl3_do_change_cipher_spec(SSL *s) 1230{ 1231 if (s->s3->hs.tls12.key_block == NULL) { 1232 if (s->session == NULL || s->session->master_key_length == 0) { 1233 /* might happen if dtls1_read_bytes() calls this */ 1234 SSLerror(s, SSL_R_CCS_RECEIVED_EARLY); 1235 return (0); 1236 } 1237 1238 s->session->cipher = s->s3->hs.cipher; 1239 if (!tls1_setup_key_block(s)) 1240 return (0); 1241 } 1242 1243 if (!tls1_change_read_cipher_state(s)) 1244 return (0); 1245 1246 /* 1247 * We have to record the message digest at this point so we can get it 1248 * before we read the finished message. 1249 */ 1250 if (!tls12_derive_peer_finished(s)) 1251 return (0); 1252 1253 return (1); 1254} 1255 1256static int 1257ssl3_write_alert(SSL *s) 1258{ 1259 if (SSL_is_dtls(s)) 1260 return do_dtls1_write(s, SSL3_RT_ALERT, s->s3->send_alert, 1261 sizeof(s->s3->send_alert)); 1262 1263 return do_ssl3_write(s, SSL3_RT_ALERT, s->s3->send_alert, 1264 sizeof(s->s3->send_alert)); 1265} 1266 1267int 1268ssl3_send_alert(SSL *s, int level, int desc) 1269{ 1270 /* If alert is fatal, remove session from cache. */ 1271 if (level == SSL3_AL_FATAL) 1272 SSL_CTX_remove_session(s->ctx, s->session); 1273 1274 s->s3->alert_dispatch = 1; 1275 s->s3->send_alert[0] = level; 1276 s->s3->send_alert[1] = desc; 1277 1278 /* 1279 * If data is still being written out, the alert will be dispatched at 1280 * some point in the future. 1281 */ 1282 if (s->s3->wbuf.left != 0) 1283 return -1; 1284 1285 return ssl3_dispatch_alert(s); 1286} 1287 1288int 1289ssl3_dispatch_alert(SSL *s) 1290{ 1291 int ret; 1292 1293 s->s3->alert_dispatch = 0; 1294 if ((ret = ssl3_write_alert(s)) <= 0) { 1295 s->s3->alert_dispatch = 1; 1296 return ret; 1297 } 1298 1299 /* 1300 * Alert sent to BIO. If it is important, flush it now. 1301 * If the message does not get sent due to non-blocking IO, 1302 * we will not worry too much. 1303 */ 1304 if (s->s3->send_alert[0] == SSL3_AL_FATAL) 1305 (void)BIO_flush(s->wbio); 1306 1307 ssl_msg_callback(s, 1, SSL3_RT_ALERT, s->s3->send_alert, 2); 1308 1309 ssl_info_callback(s, SSL_CB_WRITE_ALERT, 1310 (s->s3->send_alert[0] << 8) | s->s3->send_alert[1]); 1311 1312 return ret; 1313} 1314