1 /* 2 * Copyright 1995-2022 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 "../ssl_local.h" 11 #include "internal/constant_time.h" 12 #include <openssl/rand.h> 13 #include "record_local.h" 14 #include "internal/cryptlib.h" 15 16 static const unsigned char ssl3_pad_1[48] = { 17 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 18 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 19 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 20 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 21 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 22 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36, 0x36 23 }; 24 25 static const unsigned char ssl3_pad_2[48] = { 26 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 27 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 28 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 29 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 30 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 31 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c, 0x5c 32 }; 33 34 /* 35 * Clear the contents of an SSL3_RECORD but retain any memory allocated 36 */ 37 void SSL3_RECORD_clear(SSL3_RECORD *r, size_t num_recs) 38 { 39 unsigned char *comp; 40 size_t i; 41 42 for (i = 0; i < num_recs; i++) { 43 comp = r[i].comp; 44 45 memset(&r[i], 0, sizeof(*r)); 46 r[i].comp = comp; 47 } 48 } 49 50 void SSL3_RECORD_release(SSL3_RECORD *r, size_t num_recs) 51 { 52 size_t i; 53 54 for (i = 0; i < num_recs; i++) { 55 OPENSSL_free(r[i].comp); 56 r[i].comp = NULL; 57 } 58 } 59 60 void SSL3_RECORD_set_seq_num(SSL3_RECORD *r, const unsigned char *seq_num) 61 { 62 memcpy(r->seq_num, seq_num, SEQ_NUM_SIZE); 63 } 64 65 /* 66 * Peeks ahead into "read_ahead" data to see if we have a whole record waiting 67 * for us in the buffer. 68 */ 69 static int ssl3_record_app_data_waiting(SSL *s) 70 { 71 SSL3_BUFFER *rbuf; 72 size_t left, len; 73 unsigned char *p; 74 75 rbuf = RECORD_LAYER_get_rbuf(&s->rlayer); 76 77 p = SSL3_BUFFER_get_buf(rbuf); 78 if (p == NULL) 79 return 0; 80 81 left = SSL3_BUFFER_get_left(rbuf); 82 83 if (left < SSL3_RT_HEADER_LENGTH) 84 return 0; 85 86 p += SSL3_BUFFER_get_offset(rbuf); 87 88 /* 89 * We only check the type and record length, we will sanity check version 90 * etc later 91 */ 92 if (*p != SSL3_RT_APPLICATION_DATA) 93 return 0; 94 95 p += 3; 96 n2s(p, len); 97 98 if (left < SSL3_RT_HEADER_LENGTH + len) 99 return 0; 100 101 return 1; 102 } 103 104 int early_data_count_ok(SSL *s, size_t length, size_t overhead, int send) 105 { 106 uint32_t max_early_data; 107 SSL_SESSION *sess = s->session; 108 109 /* 110 * If we are a client then we always use the max_early_data from the 111 * session/psksession. Otherwise we go with the lowest out of the max early 112 * data set in the session and the configured max_early_data. 113 */ 114 if (!s->server && sess->ext.max_early_data == 0) { 115 if (!ossl_assert(s->psksession != NULL 116 && s->psksession->ext.max_early_data > 0)) { 117 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_EARLY_DATA_COUNT_OK, 118 ERR_R_INTERNAL_ERROR); 119 return 0; 120 } 121 sess = s->psksession; 122 } 123 124 if (!s->server) 125 max_early_data = sess->ext.max_early_data; 126 else if (s->ext.early_data != SSL_EARLY_DATA_ACCEPTED) 127 max_early_data = s->recv_max_early_data; 128 else 129 max_early_data = s->recv_max_early_data < sess->ext.max_early_data 130 ? s->recv_max_early_data : sess->ext.max_early_data; 131 132 if (max_early_data == 0) { 133 SSLfatal(s, send ? SSL_AD_INTERNAL_ERROR : SSL_AD_UNEXPECTED_MESSAGE, 134 SSL_F_EARLY_DATA_COUNT_OK, SSL_R_TOO_MUCH_EARLY_DATA); 135 return 0; 136 } 137 138 /* If we are dealing with ciphertext we need to allow for the overhead */ 139 max_early_data += overhead; 140 141 if (s->early_data_count + length > max_early_data) { 142 SSLfatal(s, send ? SSL_AD_INTERNAL_ERROR : SSL_AD_UNEXPECTED_MESSAGE, 143 SSL_F_EARLY_DATA_COUNT_OK, SSL_R_TOO_MUCH_EARLY_DATA); 144 return 0; 145 } 146 s->early_data_count += length; 147 148 return 1; 149 } 150 151 /* 152 * MAX_EMPTY_RECORDS defines the number of consecutive, empty records that 153 * will be processed per call to ssl3_get_record. Without this limit an 154 * attacker could send empty records at a faster rate than we can process and 155 * cause ssl3_get_record to loop forever. 156 */ 157 #define MAX_EMPTY_RECORDS 32 158 159 #define SSL2_RT_HEADER_LENGTH 2 160 /*- 161 * Call this to get new input records. 162 * It will return <= 0 if more data is needed, normally due to an error 163 * or non-blocking IO. 164 * When it finishes, |numrpipes| records have been decoded. For each record 'i': 165 * rr[i].type - is the type of record 166 * rr[i].data, - data 167 * rr[i].length, - number of bytes 168 * Multiple records will only be returned if the record types are all 169 * SSL3_RT_APPLICATION_DATA. The number of records returned will always be <= 170 * |max_pipelines| 171 */ 172 /* used only by ssl3_read_bytes */ 173 int ssl3_get_record(SSL *s) 174 { 175 int enc_err, rret; 176 int i; 177 size_t more, n; 178 SSL3_RECORD *rr, *thisrr; 179 SSL3_BUFFER *rbuf; 180 SSL_SESSION *sess; 181 unsigned char *p; 182 unsigned char md[EVP_MAX_MD_SIZE]; 183 unsigned int version; 184 size_t mac_size; 185 int imac_size; 186 size_t num_recs = 0, max_recs, j; 187 PACKET pkt, sslv2pkt; 188 size_t first_rec_len; 189 int using_ktls; 190 191 rr = RECORD_LAYER_get_rrec(&s->rlayer); 192 rbuf = RECORD_LAYER_get_rbuf(&s->rlayer); 193 max_recs = s->max_pipelines; 194 if (max_recs == 0) 195 max_recs = 1; 196 sess = s->session; 197 198 /* 199 * KTLS reads full records. If there is any data left, 200 * then it is from before enabling ktls. 201 */ 202 using_ktls = BIO_get_ktls_recv(s->rbio) && SSL3_BUFFER_get_left(rbuf) == 0; 203 204 do { 205 thisrr = &rr[num_recs]; 206 207 /* check if we have the header */ 208 if ((RECORD_LAYER_get_rstate(&s->rlayer) != SSL_ST_READ_BODY) || 209 (RECORD_LAYER_get_packet_length(&s->rlayer) 210 < SSL3_RT_HEADER_LENGTH)) { 211 size_t sslv2len; 212 unsigned int type; 213 214 rret = ssl3_read_n(s, SSL3_RT_HEADER_LENGTH, 215 SSL3_BUFFER_get_len(rbuf), 0, 216 num_recs == 0 ? 1 : 0, &n); 217 if (rret <= 0) { 218 #ifndef OPENSSL_NO_KTLS 219 if (!BIO_get_ktls_recv(s->rbio) || rret == 0) 220 return rret; /* error or non-blocking */ 221 switch (errno) { 222 case EBADMSG: 223 SSLfatal(s, SSL_AD_BAD_RECORD_MAC, 224 SSL_F_SSL3_GET_RECORD, 225 SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC); 226 break; 227 case EMSGSIZE: 228 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, 229 SSL_F_SSL3_GET_RECORD, 230 SSL_R_PACKET_LENGTH_TOO_LONG); 231 break; 232 case EINVAL: 233 SSLfatal(s, SSL_AD_PROTOCOL_VERSION, 234 SSL_F_SSL3_GET_RECORD, 235 SSL_R_WRONG_VERSION_NUMBER); 236 break; 237 default: 238 break; 239 } 240 #endif 241 return rret; 242 } 243 RECORD_LAYER_set_rstate(&s->rlayer, SSL_ST_READ_BODY); 244 245 p = RECORD_LAYER_get_packet(&s->rlayer); 246 if (!PACKET_buf_init(&pkt, RECORD_LAYER_get_packet(&s->rlayer), 247 RECORD_LAYER_get_packet_length(&s->rlayer))) { 248 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_SSL3_GET_RECORD, 249 ERR_R_INTERNAL_ERROR); 250 return -1; 251 } 252 sslv2pkt = pkt; 253 if (!PACKET_get_net_2_len(&sslv2pkt, &sslv2len) 254 || !PACKET_get_1(&sslv2pkt, &type)) { 255 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_SSL3_GET_RECORD, 256 ERR_R_INTERNAL_ERROR); 257 return -1; 258 } 259 /* 260 * The first record received by the server may be a V2ClientHello. 261 */ 262 if (s->server && RECORD_LAYER_is_first_record(&s->rlayer) 263 && (sslv2len & 0x8000) != 0 264 && (type == SSL2_MT_CLIENT_HELLO)) { 265 /* 266 * SSLv2 style record 267 * 268 * |num_recs| here will actually always be 0 because 269 * |num_recs > 0| only ever occurs when we are processing 270 * multiple app data records - which we know isn't the case here 271 * because it is an SSLv2ClientHello. We keep it using 272 * |num_recs| for the sake of consistency 273 */ 274 thisrr->type = SSL3_RT_HANDSHAKE; 275 thisrr->rec_version = SSL2_VERSION; 276 277 thisrr->length = sslv2len & 0x7fff; 278 279 if (thisrr->length > SSL3_BUFFER_get_len(rbuf) 280 - SSL2_RT_HEADER_LENGTH) { 281 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_SSL3_GET_RECORD, 282 SSL_R_PACKET_LENGTH_TOO_LONG); 283 return -1; 284 } 285 286 if (thisrr->length < MIN_SSL2_RECORD_LEN) { 287 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_SSL3_GET_RECORD, 288 SSL_R_LENGTH_TOO_SHORT); 289 return -1; 290 } 291 } else { 292 /* SSLv3+ style record */ 293 if (s->msg_callback) 294 s->msg_callback(0, 0, SSL3_RT_HEADER, p, 5, s, 295 s->msg_callback_arg); 296 297 /* Pull apart the header into the SSL3_RECORD */ 298 if (!PACKET_get_1(&pkt, &type) 299 || !PACKET_get_net_2(&pkt, &version) 300 || !PACKET_get_net_2_len(&pkt, &thisrr->length)) { 301 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_SSL3_GET_RECORD, 302 ERR_R_INTERNAL_ERROR); 303 return -1; 304 } 305 thisrr->type = type; 306 thisrr->rec_version = version; 307 308 /* 309 * Lets check version. In TLSv1.3 we only check this field 310 * when encryption is occurring (see later check). For the 311 * ServerHello after an HRR we haven't actually selected TLSv1.3 312 * yet, but we still treat it as TLSv1.3, so we must check for 313 * that explicitly 314 */ 315 if (!s->first_packet && !SSL_IS_TLS13(s) 316 && s->hello_retry_request != SSL_HRR_PENDING 317 && version != (unsigned int)s->version) { 318 if ((s->version & 0xFF00) == (version & 0xFF00) 319 && !s->enc_write_ctx && !s->write_hash) { 320 if (thisrr->type == SSL3_RT_ALERT) { 321 /* 322 * The record is using an incorrect version number, 323 * but what we've got appears to be an alert. We 324 * haven't read the body yet to check whether its a 325 * fatal or not - but chances are it is. We probably 326 * shouldn't send a fatal alert back. We'll just 327 * end. 328 */ 329 SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_SSL3_GET_RECORD, 330 SSL_R_WRONG_VERSION_NUMBER); 331 return -1; 332 } 333 /* 334 * Send back error using their minor version number :-) 335 */ 336 s->version = (unsigned short)version; 337 } 338 SSLfatal(s, SSL_AD_PROTOCOL_VERSION, SSL_F_SSL3_GET_RECORD, 339 SSL_R_WRONG_VERSION_NUMBER); 340 return -1; 341 } 342 343 if ((version >> 8) != SSL3_VERSION_MAJOR) { 344 if (RECORD_LAYER_is_first_record(&s->rlayer)) { 345 /* Go back to start of packet, look at the five bytes 346 * that we have. */ 347 p = RECORD_LAYER_get_packet(&s->rlayer); 348 if (strncmp((char *)p, "GET ", 4) == 0 || 349 strncmp((char *)p, "POST ", 5) == 0 || 350 strncmp((char *)p, "HEAD ", 5) == 0 || 351 strncmp((char *)p, "PUT ", 4) == 0) { 352 SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_SSL3_GET_RECORD, 353 SSL_R_HTTP_REQUEST); 354 return -1; 355 } else if (strncmp((char *)p, "CONNE", 5) == 0) { 356 SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_SSL3_GET_RECORD, 357 SSL_R_HTTPS_PROXY_REQUEST); 358 return -1; 359 } 360 361 /* Doesn't look like TLS - don't send an alert */ 362 SSLfatal(s, SSL_AD_NO_ALERT, SSL_F_SSL3_GET_RECORD, 363 SSL_R_WRONG_VERSION_NUMBER); 364 return -1; 365 } else { 366 SSLfatal(s, SSL_AD_PROTOCOL_VERSION, 367 SSL_F_SSL3_GET_RECORD, 368 SSL_R_WRONG_VERSION_NUMBER); 369 return -1; 370 } 371 } 372 373 if (SSL_IS_TLS13(s) 374 && s->enc_read_ctx != NULL 375 && !using_ktls) { 376 if (thisrr->type != SSL3_RT_APPLICATION_DATA 377 && (thisrr->type != SSL3_RT_CHANGE_CIPHER_SPEC 378 || !SSL_IS_FIRST_HANDSHAKE(s)) 379 && (thisrr->type != SSL3_RT_ALERT 380 || s->statem.enc_read_state 381 != ENC_READ_STATE_ALLOW_PLAIN_ALERTS)) { 382 SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, 383 SSL_F_SSL3_GET_RECORD, SSL_R_BAD_RECORD_TYPE); 384 return -1; 385 } 386 if (thisrr->rec_version != TLS1_2_VERSION) { 387 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_SSL3_GET_RECORD, 388 SSL_R_WRONG_VERSION_NUMBER); 389 return -1; 390 } 391 } 392 393 if (thisrr->length > 394 SSL3_BUFFER_get_len(rbuf) - SSL3_RT_HEADER_LENGTH) { 395 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_SSL3_GET_RECORD, 396 SSL_R_PACKET_LENGTH_TOO_LONG); 397 return -1; 398 } 399 } 400 401 /* now s->rlayer.rstate == SSL_ST_READ_BODY */ 402 } 403 404 if (SSL_IS_TLS13(s)) { 405 size_t len = SSL3_RT_MAX_TLS13_ENCRYPTED_LENGTH; 406 407 /* KTLS strips the inner record type. */ 408 if (using_ktls) 409 len = SSL3_RT_MAX_ENCRYPTED_LENGTH; 410 411 if (thisrr->length > len) { 412 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_SSL3_GET_RECORD, 413 SSL_R_ENCRYPTED_LENGTH_TOO_LONG); 414 return -1; 415 } 416 } else { 417 size_t len = SSL3_RT_MAX_ENCRYPTED_LENGTH; 418 419 #ifndef OPENSSL_NO_COMP 420 /* 421 * If OPENSSL_NO_COMP is defined then SSL3_RT_MAX_ENCRYPTED_LENGTH 422 * does not include the compression overhead anyway. 423 */ 424 if (s->expand == NULL) 425 len -= SSL3_RT_MAX_COMPRESSED_OVERHEAD; 426 #endif 427 428 /* KTLS may use all of the buffer */ 429 if (using_ktls) 430 len = SSL3_BUFFER_get_left(rbuf); 431 432 if (thisrr->length > len) { 433 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_SSL3_GET_RECORD, 434 SSL_R_ENCRYPTED_LENGTH_TOO_LONG); 435 return -1; 436 } 437 } 438 439 /* 440 * s->rlayer.rstate == SSL_ST_READ_BODY, get and decode the data. 441 * Calculate how much more data we need to read for the rest of the 442 * record 443 */ 444 if (thisrr->rec_version == SSL2_VERSION) { 445 more = thisrr->length + SSL2_RT_HEADER_LENGTH 446 - SSL3_RT_HEADER_LENGTH; 447 } else { 448 more = thisrr->length; 449 } 450 451 if (more > 0) { 452 /* now s->rlayer.packet_length == SSL3_RT_HEADER_LENGTH */ 453 454 rret = ssl3_read_n(s, more, more, 1, 0, &n); 455 if (rret <= 0) 456 return rret; /* error or non-blocking io */ 457 } 458 459 /* set state for later operations */ 460 RECORD_LAYER_set_rstate(&s->rlayer, SSL_ST_READ_HEADER); 461 462 /* 463 * At this point, s->rlayer.packet_length == SSL3_RT_HEADER_LENGTH 464 * + thisrr->length, or s->rlayer.packet_length == SSL2_RT_HEADER_LENGTH 465 * + thisrr->length and we have that many bytes in s->rlayer.packet 466 */ 467 if (thisrr->rec_version == SSL2_VERSION) { 468 thisrr->input = 469 &(RECORD_LAYER_get_packet(&s->rlayer)[SSL2_RT_HEADER_LENGTH]); 470 } else { 471 thisrr->input = 472 &(RECORD_LAYER_get_packet(&s->rlayer)[SSL3_RT_HEADER_LENGTH]); 473 } 474 475 /* 476 * ok, we can now read from 's->rlayer.packet' data into 'thisrr'. 477 * thisrr->input points at thisrr->length bytes, which need to be copied 478 * into thisrr->data by either the decryption or by the decompression. 479 * When the data is 'copied' into the thisrr->data buffer, 480 * thisrr->input will be updated to point at the new buffer 481 */ 482 483 /* 484 * We now have - encrypted [ MAC [ compressed [ plain ] ] ] 485 * thisrr->length bytes of encrypted compressed stuff. 486 */ 487 488 /* decrypt in place in 'thisrr->input' */ 489 thisrr->data = thisrr->input; 490 thisrr->orig_len = thisrr->length; 491 492 /* Mark this record as not read by upper layers yet */ 493 thisrr->read = 0; 494 495 num_recs++; 496 497 /* we have pulled in a full packet so zero things */ 498 RECORD_LAYER_reset_packet_length(&s->rlayer); 499 RECORD_LAYER_clear_first_record(&s->rlayer); 500 } while (num_recs < max_recs 501 && thisrr->type == SSL3_RT_APPLICATION_DATA 502 && SSL_USE_EXPLICIT_IV(s) 503 && s->enc_read_ctx != NULL 504 && (EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(s->enc_read_ctx)) 505 & EVP_CIPH_FLAG_PIPELINE) 506 && ssl3_record_app_data_waiting(s)); 507 508 if (num_recs == 1 509 && thisrr->type == SSL3_RT_CHANGE_CIPHER_SPEC 510 && (SSL_IS_TLS13(s) || s->hello_retry_request != SSL_HRR_NONE) 511 && SSL_IS_FIRST_HANDSHAKE(s)) { 512 /* 513 * CCS messages must be exactly 1 byte long, containing the value 0x01 514 */ 515 if (thisrr->length != 1 || thisrr->data[0] != 0x01) { 516 SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_SSL3_GET_RECORD, 517 SSL_R_INVALID_CCS_MESSAGE); 518 return -1; 519 } 520 /* 521 * CCS messages are ignored in TLSv1.3. We treat it like an empty 522 * handshake record 523 */ 524 thisrr->type = SSL3_RT_HANDSHAKE; 525 RECORD_LAYER_inc_empty_record_count(&s->rlayer); 526 if (RECORD_LAYER_get_empty_record_count(&s->rlayer) 527 > MAX_EMPTY_RECORDS) { 528 SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, SSL_F_SSL3_GET_RECORD, 529 SSL_R_UNEXPECTED_CCS_MESSAGE); 530 return -1; 531 } 532 thisrr->read = 1; 533 RECORD_LAYER_set_numrpipes(&s->rlayer, 1); 534 535 return 1; 536 } 537 538 if (using_ktls) 539 goto skip_decryption; 540 541 /* 542 * If in encrypt-then-mac mode calculate mac from encrypted record. All 543 * the details below are public so no timing details can leak. 544 */ 545 if (SSL_READ_ETM(s) && s->read_hash) { 546 unsigned char *mac; 547 /* TODO(size_t): convert this to do size_t properly */ 548 imac_size = EVP_MD_CTX_size(s->read_hash); 549 if (!ossl_assert(imac_size >= 0 && imac_size <= EVP_MAX_MD_SIZE)) { 550 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_SSL3_GET_RECORD, 551 ERR_LIB_EVP); 552 return -1; 553 } 554 mac_size = (size_t)imac_size; 555 for (j = 0; j < num_recs; j++) { 556 thisrr = &rr[j]; 557 558 if (thisrr->length < mac_size) { 559 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_SSL3_GET_RECORD, 560 SSL_R_LENGTH_TOO_SHORT); 561 return -1; 562 } 563 thisrr->length -= mac_size; 564 mac = thisrr->data + thisrr->length; 565 i = s->method->ssl3_enc->mac(s, thisrr, md, 0 /* not send */ ); 566 if (i == 0 || CRYPTO_memcmp(md, mac, mac_size) != 0) { 567 SSLfatal(s, SSL_AD_BAD_RECORD_MAC, SSL_F_SSL3_GET_RECORD, 568 SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC); 569 return -1; 570 } 571 } 572 } 573 574 first_rec_len = rr[0].length; 575 576 enc_err = s->method->ssl3_enc->enc(s, rr, num_recs, 0); 577 578 /*- 579 * enc_err is: 580 * 0: (in non-constant time) if the record is publicly invalid. 581 * 1: if the padding is valid 582 * -1: if the padding is invalid 583 */ 584 if (enc_err == 0) { 585 if (ossl_statem_in_error(s)) { 586 /* SSLfatal() already got called */ 587 return -1; 588 } 589 if (num_recs == 1 && ossl_statem_skip_early_data(s)) { 590 /* 591 * Valid early_data that we cannot decrypt might fail here as 592 * publicly invalid. We treat it like an empty record. 593 */ 594 595 thisrr = &rr[0]; 596 597 if (!early_data_count_ok(s, thisrr->length, 598 EARLY_DATA_CIPHERTEXT_OVERHEAD, 0)) { 599 /* SSLfatal() already called */ 600 return -1; 601 } 602 603 thisrr->length = 0; 604 thisrr->read = 1; 605 RECORD_LAYER_set_numrpipes(&s->rlayer, 1); 606 RECORD_LAYER_reset_read_sequence(&s->rlayer); 607 return 1; 608 } 609 SSLfatal(s, SSL_AD_BAD_RECORD_MAC, SSL_F_SSL3_GET_RECORD, 610 SSL_R_BLOCK_CIPHER_PAD_IS_WRONG); 611 return -1; 612 } 613 #ifdef SSL_DEBUG 614 printf("dec %lu\n", (unsigned long)rr[0].length); 615 { 616 size_t z; 617 for (z = 0; z < rr[0].length; z++) 618 printf("%02X%c", rr[0].data[z], ((z + 1) % 16) ? ' ' : '\n'); 619 } 620 printf("\n"); 621 #endif 622 623 /* r->length is now the compressed data plus mac */ 624 if ((sess != NULL) && 625 (s->enc_read_ctx != NULL) && 626 (!SSL_READ_ETM(s) && EVP_MD_CTX_md(s->read_hash) != NULL)) { 627 /* s->read_hash != NULL => mac_size != -1 */ 628 unsigned char *mac = NULL; 629 unsigned char mac_tmp[EVP_MAX_MD_SIZE]; 630 631 mac_size = EVP_MD_CTX_size(s->read_hash); 632 if (!ossl_assert(mac_size <= EVP_MAX_MD_SIZE)) { 633 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_SSL3_GET_RECORD, 634 ERR_R_INTERNAL_ERROR); 635 return -1; 636 } 637 638 for (j = 0; j < num_recs; j++) { 639 thisrr = &rr[j]; 640 /* 641 * orig_len is the length of the record before any padding was 642 * removed. This is public information, as is the MAC in use, 643 * therefore we can safely process the record in a different amount 644 * of time if it's too short to possibly contain a MAC. 645 */ 646 if (thisrr->orig_len < mac_size || 647 /* CBC records must have a padding length byte too. */ 648 (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE && 649 thisrr->orig_len < mac_size + 1)) { 650 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_SSL3_GET_RECORD, 651 SSL_R_LENGTH_TOO_SHORT); 652 return -1; 653 } 654 655 if (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE) { 656 /* 657 * We update the length so that the TLS header bytes can be 658 * constructed correctly but we need to extract the MAC in 659 * constant time from within the record, without leaking the 660 * contents of the padding bytes. 661 */ 662 mac = mac_tmp; 663 if (!ssl3_cbc_copy_mac(mac_tmp, thisrr, mac_size)) { 664 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_SSL3_GET_RECORD, 665 ERR_R_INTERNAL_ERROR); 666 return -1; 667 } 668 thisrr->length -= mac_size; 669 } else { 670 /* 671 * In this case there's no padding, so |rec->orig_len| equals 672 * |rec->length| and we checked that there's enough bytes for 673 * |mac_size| above. 674 */ 675 thisrr->length -= mac_size; 676 mac = &thisrr->data[thisrr->length]; 677 } 678 679 i = s->method->ssl3_enc->mac(s, thisrr, md, 0 /* not send */ ); 680 if (i == 0 || mac == NULL 681 || CRYPTO_memcmp(md, mac, (size_t)mac_size) != 0) 682 enc_err = -1; 683 if (thisrr->length > SSL3_RT_MAX_COMPRESSED_LENGTH + mac_size) 684 enc_err = -1; 685 } 686 } 687 688 if (enc_err < 0) { 689 if (ossl_statem_in_error(s)) { 690 /* We already called SSLfatal() */ 691 return -1; 692 } 693 if (num_recs == 1 && ossl_statem_skip_early_data(s)) { 694 /* 695 * We assume this is unreadable early_data - we treat it like an 696 * empty record 697 */ 698 699 /* 700 * The record length may have been modified by the mac check above 701 * so we use the previously saved value 702 */ 703 if (!early_data_count_ok(s, first_rec_len, 704 EARLY_DATA_CIPHERTEXT_OVERHEAD, 0)) { 705 /* SSLfatal() already called */ 706 return -1; 707 } 708 709 thisrr = &rr[0]; 710 thisrr->length = 0; 711 thisrr->read = 1; 712 RECORD_LAYER_set_numrpipes(&s->rlayer, 1); 713 RECORD_LAYER_reset_read_sequence(&s->rlayer); 714 return 1; 715 } 716 /* 717 * A separate 'decryption_failed' alert was introduced with TLS 1.0, 718 * SSL 3.0 only has 'bad_record_mac'. But unless a decryption 719 * failure is directly visible from the ciphertext anyway, we should 720 * not reveal which kind of error occurred -- this might become 721 * visible to an attacker (e.g. via a logfile) 722 */ 723 SSLfatal(s, SSL_AD_BAD_RECORD_MAC, SSL_F_SSL3_GET_RECORD, 724 SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC); 725 return -1; 726 } 727 728 skip_decryption: 729 730 for (j = 0; j < num_recs; j++) { 731 thisrr = &rr[j]; 732 733 /* thisrr->length is now just compressed */ 734 if (s->expand != NULL) { 735 if (thisrr->length > SSL3_RT_MAX_COMPRESSED_LENGTH) { 736 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_SSL3_GET_RECORD, 737 SSL_R_COMPRESSED_LENGTH_TOO_LONG); 738 return -1; 739 } 740 if (!ssl3_do_uncompress(s, thisrr)) { 741 SSLfatal(s, SSL_AD_DECOMPRESSION_FAILURE, SSL_F_SSL3_GET_RECORD, 742 SSL_R_BAD_DECOMPRESSION); 743 return -1; 744 } 745 } 746 747 if (SSL_IS_TLS13(s) 748 && s->enc_read_ctx != NULL 749 && thisrr->type != SSL3_RT_ALERT) { 750 /* 751 * The following logic are irrelevant in KTLS: the kernel provides 752 * unprotected record and thus record type represent the actual 753 * content type, and padding is already removed and thisrr->type and 754 * thisrr->length should have the correct values. 755 */ 756 if (!using_ktls) { 757 size_t end; 758 759 if (thisrr->length == 0 760 || thisrr->type != SSL3_RT_APPLICATION_DATA) { 761 SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, 762 SSL_F_SSL3_GET_RECORD, SSL_R_BAD_RECORD_TYPE); 763 return -1; 764 } 765 766 /* Strip trailing padding */ 767 for (end = thisrr->length - 1; end > 0 && thisrr->data[end] == 0; 768 end--) 769 continue; 770 771 thisrr->length = end; 772 thisrr->type = thisrr->data[end]; 773 } 774 if (thisrr->type != SSL3_RT_APPLICATION_DATA 775 && thisrr->type != SSL3_RT_ALERT 776 && thisrr->type != SSL3_RT_HANDSHAKE) { 777 SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, SSL_F_SSL3_GET_RECORD, 778 SSL_R_BAD_RECORD_TYPE); 779 return -1; 780 } 781 if (s->msg_callback) 782 s->msg_callback(0, s->version, SSL3_RT_INNER_CONTENT_TYPE, 783 &thisrr->type, 1, s, s->msg_callback_arg); 784 } 785 786 /* 787 * TLSv1.3 alert and handshake records are required to be non-zero in 788 * length. 789 */ 790 if (SSL_IS_TLS13(s) 791 && (thisrr->type == SSL3_RT_HANDSHAKE 792 || thisrr->type == SSL3_RT_ALERT) 793 && thisrr->length == 0) { 794 SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, SSL_F_SSL3_GET_RECORD, 795 SSL_R_BAD_LENGTH); 796 return -1; 797 } 798 799 /* 800 * Usually thisrr->length is the length of a single record, but when 801 * KTLS handles the decryption, thisrr->length may be larger than 802 * SSL3_RT_MAX_PLAIN_LENGTH because the kernel may have coalesced 803 * multiple records. 804 * Therefore we have to rely on KTLS to check the plaintext length 805 * limit in the kernel. 806 */ 807 if (thisrr->length > SSL3_RT_MAX_PLAIN_LENGTH && !using_ktls) { 808 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_SSL3_GET_RECORD, 809 SSL_R_DATA_LENGTH_TOO_LONG); 810 return -1; 811 } 812 813 /* 814 * Check if the received packet overflows the current 815 * Max Fragment Length setting. 816 * Note: USE_MAX_FRAGMENT_LENGTH_EXT and KTLS are mutually exclusive. 817 */ 818 if (s->session != NULL && USE_MAX_FRAGMENT_LENGTH_EXT(s->session) 819 && thisrr->length > GET_MAX_FRAGMENT_LENGTH(s->session)) { 820 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_SSL3_GET_RECORD, 821 SSL_R_DATA_LENGTH_TOO_LONG); 822 return -1; 823 } 824 825 thisrr->off = 0; 826 /*- 827 * So at this point the following is true 828 * thisrr->type is the type of record 829 * thisrr->length == number of bytes in record 830 * thisrr->off == offset to first valid byte 831 * thisrr->data == where to take bytes from, increment after use :-). 832 */ 833 834 /* just read a 0 length packet */ 835 if (thisrr->length == 0) { 836 RECORD_LAYER_inc_empty_record_count(&s->rlayer); 837 if (RECORD_LAYER_get_empty_record_count(&s->rlayer) 838 > MAX_EMPTY_RECORDS) { 839 SSLfatal(s, SSL_AD_UNEXPECTED_MESSAGE, SSL_F_SSL3_GET_RECORD, 840 SSL_R_RECORD_TOO_SMALL); 841 return -1; 842 } 843 } else { 844 RECORD_LAYER_reset_empty_record_count(&s->rlayer); 845 } 846 } 847 848 if (s->early_data_state == SSL_EARLY_DATA_READING) { 849 thisrr = &rr[0]; 850 if (thisrr->type == SSL3_RT_APPLICATION_DATA 851 && !early_data_count_ok(s, thisrr->length, 0, 0)) { 852 /* SSLfatal already called */ 853 return -1; 854 } 855 } 856 857 RECORD_LAYER_set_numrpipes(&s->rlayer, num_recs); 858 return 1; 859 } 860 861 int ssl3_do_uncompress(SSL *ssl, SSL3_RECORD *rr) 862 { 863 #ifndef OPENSSL_NO_COMP 864 int i; 865 866 if (rr->comp == NULL) { 867 rr->comp = (unsigned char *) 868 OPENSSL_malloc(SSL3_RT_MAX_ENCRYPTED_LENGTH); 869 } 870 if (rr->comp == NULL) 871 return 0; 872 873 /* TODO(size_t): Convert this call */ 874 i = COMP_expand_block(ssl->expand, rr->comp, 875 SSL3_RT_MAX_PLAIN_LENGTH, rr->data, (int)rr->length); 876 if (i < 0) 877 return 0; 878 else 879 rr->length = i; 880 rr->data = rr->comp; 881 #endif 882 return 1; 883 } 884 885 int ssl3_do_compress(SSL *ssl, SSL3_RECORD *wr) 886 { 887 #ifndef OPENSSL_NO_COMP 888 int i; 889 890 /* TODO(size_t): Convert this call */ 891 i = COMP_compress_block(ssl->compress, wr->data, 892 (int)(wr->length + SSL3_RT_MAX_COMPRESSED_OVERHEAD), 893 wr->input, (int)wr->length); 894 if (i < 0) 895 return 0; 896 else 897 wr->length = i; 898 899 wr->input = wr->data; 900 #endif 901 return 1; 902 } 903 904 /*- 905 * ssl3_enc encrypts/decrypts |n_recs| records in |inrecs|. Will call 906 * SSLfatal() for internal errors, but not otherwise. 907 * 908 * Returns: 909 * 0: (in non-constant time) if the record is publicly invalid (i.e. too 910 * short etc). 911 * 1: if the record's padding is valid / the encryption was successful. 912 * -1: if the record's padding is invalid or, if sending, an internal error 913 * occurred. 914 */ 915 int ssl3_enc(SSL *s, SSL3_RECORD *inrecs, size_t n_recs, int sending) 916 { 917 SSL3_RECORD *rec; 918 EVP_CIPHER_CTX *ds; 919 size_t l, i; 920 size_t bs, mac_size = 0; 921 int imac_size; 922 const EVP_CIPHER *enc; 923 924 rec = inrecs; 925 /* 926 * We shouldn't ever be called with more than one record in the SSLv3 case 927 */ 928 if (n_recs != 1) 929 return 0; 930 if (sending) { 931 ds = s->enc_write_ctx; 932 if (s->enc_write_ctx == NULL) 933 enc = NULL; 934 else 935 enc = EVP_CIPHER_CTX_cipher(s->enc_write_ctx); 936 } else { 937 ds = s->enc_read_ctx; 938 if (s->enc_read_ctx == NULL) 939 enc = NULL; 940 else 941 enc = EVP_CIPHER_CTX_cipher(s->enc_read_ctx); 942 } 943 944 if ((s->session == NULL) || (ds == NULL) || (enc == NULL)) { 945 memmove(rec->data, rec->input, rec->length); 946 rec->input = rec->data; 947 } else { 948 l = rec->length; 949 /* TODO(size_t): Convert this call */ 950 bs = EVP_CIPHER_CTX_block_size(ds); 951 952 /* COMPRESS */ 953 954 if ((bs != 1) && sending) { 955 i = bs - (l % bs); 956 957 /* we need to add 'i-1' padding bytes */ 958 l += i; 959 /* 960 * the last of these zero bytes will be overwritten with the 961 * padding length. 962 */ 963 memset(&rec->input[rec->length], 0, i); 964 rec->length += i; 965 rec->input[l - 1] = (unsigned char)(i - 1); 966 } 967 968 if (!sending) { 969 if (l == 0 || l % bs != 0) 970 return 0; 971 /* otherwise, rec->length >= bs */ 972 } 973 974 /* TODO(size_t): Convert this call */ 975 if (EVP_Cipher(ds, rec->data, rec->input, (unsigned int)l) < 1) 976 return -1; 977 978 if (EVP_MD_CTX_md(s->read_hash) != NULL) { 979 /* TODO(size_t): convert me */ 980 imac_size = EVP_MD_CTX_size(s->read_hash); 981 if (imac_size < 0) { 982 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_SSL3_ENC, 983 ERR_R_INTERNAL_ERROR); 984 return -1; 985 } 986 mac_size = (size_t)imac_size; 987 } 988 if ((bs != 1) && !sending) 989 return ssl3_cbc_remove_padding(rec, bs, mac_size); 990 } 991 return 1; 992 } 993 994 #define MAX_PADDING 256 995 /*- 996 * tls1_enc encrypts/decrypts |n_recs| in |recs|. Will call SSLfatal() for 997 * internal errors, but not otherwise. 998 * 999 * Returns: 1000 * 0: (in non-constant time) if the record is publicly invalid (i.e. too 1001 * short etc). 1002 * 1: if the record's padding is valid / the encryption was successful. 1003 * -1: if the record's padding/AEAD-authenticator is invalid or, if sending, 1004 * an internal error occurred. 1005 */ 1006 int tls1_enc(SSL *s, SSL3_RECORD *recs, size_t n_recs, int sending) 1007 { 1008 EVP_CIPHER_CTX *ds; 1009 size_t reclen[SSL_MAX_PIPELINES]; 1010 unsigned char buf[SSL_MAX_PIPELINES][EVP_AEAD_TLS1_AAD_LEN]; 1011 int i, pad = 0, ret, tmpr; 1012 size_t bs, mac_size = 0, ctr, padnum, loop; 1013 unsigned char padval; 1014 int imac_size; 1015 const EVP_CIPHER *enc; 1016 1017 if (n_recs == 0) { 1018 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC, 1019 ERR_R_INTERNAL_ERROR); 1020 return 0; 1021 } 1022 1023 if (sending) { 1024 if (EVP_MD_CTX_md(s->write_hash)) { 1025 int n = EVP_MD_CTX_size(s->write_hash); 1026 if (!ossl_assert(n >= 0)) { 1027 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC, 1028 ERR_R_INTERNAL_ERROR); 1029 return -1; 1030 } 1031 } 1032 ds = s->enc_write_ctx; 1033 if (s->enc_write_ctx == NULL) 1034 enc = NULL; 1035 else { 1036 int ivlen; 1037 enc = EVP_CIPHER_CTX_cipher(s->enc_write_ctx); 1038 /* For TLSv1.1 and later explicit IV */ 1039 if (SSL_USE_EXPLICIT_IV(s) 1040 && EVP_CIPHER_mode(enc) == EVP_CIPH_CBC_MODE) 1041 ivlen = EVP_CIPHER_iv_length(enc); 1042 else 1043 ivlen = 0; 1044 if (ivlen > 1) { 1045 for (ctr = 0; ctr < n_recs; ctr++) { 1046 if (recs[ctr].data != recs[ctr].input) { 1047 /* 1048 * we can't write into the input stream: Can this ever 1049 * happen?? (steve) 1050 */ 1051 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC, 1052 ERR_R_INTERNAL_ERROR); 1053 return -1; 1054 } else if (RAND_bytes(recs[ctr].input, ivlen) <= 0) { 1055 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC, 1056 ERR_R_INTERNAL_ERROR); 1057 return -1; 1058 } 1059 } 1060 } 1061 } 1062 } else { 1063 if (EVP_MD_CTX_md(s->read_hash)) { 1064 int n = EVP_MD_CTX_size(s->read_hash); 1065 if (!ossl_assert(n >= 0)) { 1066 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC, 1067 ERR_R_INTERNAL_ERROR); 1068 return -1; 1069 } 1070 } 1071 ds = s->enc_read_ctx; 1072 if (s->enc_read_ctx == NULL) 1073 enc = NULL; 1074 else 1075 enc = EVP_CIPHER_CTX_cipher(s->enc_read_ctx); 1076 } 1077 1078 if ((s->session == NULL) || (ds == NULL) || (enc == NULL)) { 1079 for (ctr = 0; ctr < n_recs; ctr++) { 1080 memmove(recs[ctr].data, recs[ctr].input, recs[ctr].length); 1081 recs[ctr].input = recs[ctr].data; 1082 } 1083 ret = 1; 1084 } else { 1085 bs = EVP_CIPHER_block_size(EVP_CIPHER_CTX_cipher(ds)); 1086 1087 if (n_recs > 1) { 1088 if (!(EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(ds)) 1089 & EVP_CIPH_FLAG_PIPELINE)) { 1090 /* 1091 * We shouldn't have been called with pipeline data if the 1092 * cipher doesn't support pipelining 1093 */ 1094 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC, 1095 SSL_R_PIPELINE_FAILURE); 1096 return -1; 1097 } 1098 } 1099 for (ctr = 0; ctr < n_recs; ctr++) { 1100 reclen[ctr] = recs[ctr].length; 1101 1102 if (EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(ds)) 1103 & EVP_CIPH_FLAG_AEAD_CIPHER) { 1104 unsigned char *seq; 1105 1106 seq = sending ? RECORD_LAYER_get_write_sequence(&s->rlayer) 1107 : RECORD_LAYER_get_read_sequence(&s->rlayer); 1108 1109 if (SSL_IS_DTLS(s)) { 1110 /* DTLS does not support pipelining */ 1111 unsigned char dtlsseq[8], *p = dtlsseq; 1112 1113 s2n(sending ? DTLS_RECORD_LAYER_get_w_epoch(&s->rlayer) : 1114 DTLS_RECORD_LAYER_get_r_epoch(&s->rlayer), p); 1115 memcpy(p, &seq[2], 6); 1116 memcpy(buf[ctr], dtlsseq, 8); 1117 } else { 1118 memcpy(buf[ctr], seq, 8); 1119 for (i = 7; i >= 0; i--) { /* increment */ 1120 ++seq[i]; 1121 if (seq[i] != 0) 1122 break; 1123 } 1124 } 1125 1126 buf[ctr][8] = recs[ctr].type; 1127 buf[ctr][9] = (unsigned char)(s->version >> 8); 1128 buf[ctr][10] = (unsigned char)(s->version); 1129 buf[ctr][11] = (unsigned char)(recs[ctr].length >> 8); 1130 buf[ctr][12] = (unsigned char)(recs[ctr].length & 0xff); 1131 pad = EVP_CIPHER_CTX_ctrl(ds, EVP_CTRL_AEAD_TLS1_AAD, 1132 EVP_AEAD_TLS1_AAD_LEN, buf[ctr]); 1133 if (pad <= 0) { 1134 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC, 1135 ERR_R_INTERNAL_ERROR); 1136 return -1; 1137 } 1138 1139 if (sending) { 1140 reclen[ctr] += pad; 1141 recs[ctr].length += pad; 1142 } 1143 1144 } else if ((bs != 1) && sending) { 1145 padnum = bs - (reclen[ctr] % bs); 1146 1147 /* Add weird padding of up to 256 bytes */ 1148 1149 if (padnum > MAX_PADDING) { 1150 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC, 1151 ERR_R_INTERNAL_ERROR); 1152 return -1; 1153 } 1154 /* we need to add 'padnum' padding bytes of value padval */ 1155 padval = (unsigned char)(padnum - 1); 1156 for (loop = reclen[ctr]; loop < reclen[ctr] + padnum; loop++) 1157 recs[ctr].input[loop] = padval; 1158 reclen[ctr] += padnum; 1159 recs[ctr].length += padnum; 1160 } 1161 1162 if (!sending) { 1163 if (reclen[ctr] == 0 || reclen[ctr] % bs != 0) 1164 return 0; 1165 } 1166 } 1167 if (n_recs > 1) { 1168 unsigned char *data[SSL_MAX_PIPELINES]; 1169 1170 /* Set the output buffers */ 1171 for (ctr = 0; ctr < n_recs; ctr++) { 1172 data[ctr] = recs[ctr].data; 1173 } 1174 if (EVP_CIPHER_CTX_ctrl(ds, EVP_CTRL_SET_PIPELINE_OUTPUT_BUFS, 1175 (int)n_recs, data) <= 0) { 1176 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC, 1177 SSL_R_PIPELINE_FAILURE); 1178 return -1; 1179 } 1180 /* Set the input buffers */ 1181 for (ctr = 0; ctr < n_recs; ctr++) { 1182 data[ctr] = recs[ctr].input; 1183 } 1184 if (EVP_CIPHER_CTX_ctrl(ds, EVP_CTRL_SET_PIPELINE_INPUT_BUFS, 1185 (int)n_recs, data) <= 0 1186 || EVP_CIPHER_CTX_ctrl(ds, EVP_CTRL_SET_PIPELINE_INPUT_LENS, 1187 (int)n_recs, reclen) <= 0) { 1188 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC, 1189 SSL_R_PIPELINE_FAILURE); 1190 return -1; 1191 } 1192 } 1193 1194 /* TODO(size_t): Convert this call */ 1195 tmpr = EVP_Cipher(ds, recs[0].data, recs[0].input, 1196 (unsigned int)reclen[0]); 1197 if ((EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(ds)) 1198 & EVP_CIPH_FLAG_CUSTOM_CIPHER) 1199 ? (tmpr < 0) 1200 : (tmpr == 0)) 1201 return -1; /* AEAD can fail to verify MAC */ 1202 1203 if (sending == 0) { 1204 if (EVP_CIPHER_mode(enc) == EVP_CIPH_GCM_MODE) { 1205 for (ctr = 0; ctr < n_recs; ctr++) { 1206 recs[ctr].data += EVP_GCM_TLS_EXPLICIT_IV_LEN; 1207 recs[ctr].input += EVP_GCM_TLS_EXPLICIT_IV_LEN; 1208 recs[ctr].length -= EVP_GCM_TLS_EXPLICIT_IV_LEN; 1209 } 1210 } else if (EVP_CIPHER_mode(enc) == EVP_CIPH_CCM_MODE) { 1211 for (ctr = 0; ctr < n_recs; ctr++) { 1212 recs[ctr].data += EVP_CCM_TLS_EXPLICIT_IV_LEN; 1213 recs[ctr].input += EVP_CCM_TLS_EXPLICIT_IV_LEN; 1214 recs[ctr].length -= EVP_CCM_TLS_EXPLICIT_IV_LEN; 1215 } 1216 } 1217 } 1218 1219 ret = 1; 1220 if (!SSL_READ_ETM(s) && EVP_MD_CTX_md(s->read_hash) != NULL) { 1221 imac_size = EVP_MD_CTX_size(s->read_hash); 1222 if (imac_size < 0) { 1223 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS1_ENC, 1224 ERR_R_INTERNAL_ERROR); 1225 return -1; 1226 } 1227 mac_size = (size_t)imac_size; 1228 } 1229 if ((bs != 1) && !sending) { 1230 int tmpret; 1231 for (ctr = 0; ctr < n_recs; ctr++) { 1232 tmpret = tls1_cbc_remove_padding(s, &recs[ctr], bs, mac_size); 1233 /* 1234 * If tmpret == 0 then this means publicly invalid so we can 1235 * short circuit things here. Otherwise we must respect constant 1236 * time behaviour. 1237 */ 1238 if (tmpret == 0) 1239 return 0; 1240 ret = constant_time_select_int(constant_time_eq_int(tmpret, 1), 1241 ret, -1); 1242 } 1243 } 1244 if (pad && !sending) { 1245 for (ctr = 0; ctr < n_recs; ctr++) { 1246 recs[ctr].length -= pad; 1247 } 1248 } 1249 } 1250 return ret; 1251 } 1252 1253 int n_ssl3_mac(SSL *ssl, SSL3_RECORD *rec, unsigned char *md, int sending) 1254 { 1255 unsigned char *mac_sec, *seq; 1256 const EVP_MD_CTX *hash; 1257 unsigned char *p, rec_char; 1258 size_t md_size; 1259 size_t npad; 1260 int t; 1261 1262 if (sending) { 1263 mac_sec = &(ssl->s3->write_mac_secret[0]); 1264 seq = RECORD_LAYER_get_write_sequence(&ssl->rlayer); 1265 hash = ssl->write_hash; 1266 } else { 1267 mac_sec = &(ssl->s3->read_mac_secret[0]); 1268 seq = RECORD_LAYER_get_read_sequence(&ssl->rlayer); 1269 hash = ssl->read_hash; 1270 } 1271 1272 t = EVP_MD_CTX_size(hash); 1273 if (t < 0) 1274 return 0; 1275 md_size = t; 1276 npad = (48 / md_size) * md_size; 1277 1278 if (!sending && 1279 EVP_CIPHER_CTX_mode(ssl->enc_read_ctx) == EVP_CIPH_CBC_MODE && 1280 ssl3_cbc_record_digest_supported(hash)) { 1281 /* 1282 * This is a CBC-encrypted record. We must avoid leaking any 1283 * timing-side channel information about how many blocks of data we 1284 * are hashing because that gives an attacker a timing-oracle. 1285 */ 1286 1287 /*- 1288 * npad is, at most, 48 bytes and that's with MD5: 1289 * 16 + 48 + 8 (sequence bytes) + 1 + 2 = 75. 1290 * 1291 * With SHA-1 (the largest hash speced for SSLv3) the hash size 1292 * goes up 4, but npad goes down by 8, resulting in a smaller 1293 * total size. 1294 */ 1295 unsigned char header[75]; 1296 size_t j = 0; 1297 memcpy(header + j, mac_sec, md_size); 1298 j += md_size; 1299 memcpy(header + j, ssl3_pad_1, npad); 1300 j += npad; 1301 memcpy(header + j, seq, 8); 1302 j += 8; 1303 header[j++] = rec->type; 1304 header[j++] = (unsigned char)(rec->length >> 8); 1305 header[j++] = (unsigned char)(rec->length & 0xff); 1306 1307 /* Final param == is SSLv3 */ 1308 if (ssl3_cbc_digest_record(hash, 1309 md, &md_size, 1310 header, rec->input, 1311 rec->length + md_size, rec->orig_len, 1312 mac_sec, md_size, 1) <= 0) 1313 return 0; 1314 } else { 1315 unsigned int md_size_u; 1316 /* Chop the digest off the end :-) */ 1317 EVP_MD_CTX *md_ctx = EVP_MD_CTX_new(); 1318 1319 if (md_ctx == NULL) 1320 return 0; 1321 1322 rec_char = rec->type; 1323 p = md; 1324 s2n(rec->length, p); 1325 if (EVP_MD_CTX_copy_ex(md_ctx, hash) <= 0 1326 || EVP_DigestUpdate(md_ctx, mac_sec, md_size) <= 0 1327 || EVP_DigestUpdate(md_ctx, ssl3_pad_1, npad) <= 0 1328 || EVP_DigestUpdate(md_ctx, seq, 8) <= 0 1329 || EVP_DigestUpdate(md_ctx, &rec_char, 1) <= 0 1330 || EVP_DigestUpdate(md_ctx, md, 2) <= 0 1331 || EVP_DigestUpdate(md_ctx, rec->input, rec->length) <= 0 1332 || EVP_DigestFinal_ex(md_ctx, md, NULL) <= 0 1333 || EVP_MD_CTX_copy_ex(md_ctx, hash) <= 0 1334 || EVP_DigestUpdate(md_ctx, mac_sec, md_size) <= 0 1335 || EVP_DigestUpdate(md_ctx, ssl3_pad_2, npad) <= 0 1336 || EVP_DigestUpdate(md_ctx, md, md_size) <= 0 1337 || EVP_DigestFinal_ex(md_ctx, md, &md_size_u) <= 0) { 1338 EVP_MD_CTX_free(md_ctx); 1339 return 0; 1340 } 1341 1342 EVP_MD_CTX_free(md_ctx); 1343 } 1344 1345 ssl3_record_sequence_update(seq); 1346 return 1; 1347 } 1348 1349 int tls1_mac(SSL *ssl, SSL3_RECORD *rec, unsigned char *md, int sending) 1350 { 1351 unsigned char *seq; 1352 EVP_MD_CTX *hash; 1353 size_t md_size; 1354 int i; 1355 EVP_MD_CTX *hmac = NULL, *mac_ctx; 1356 unsigned char header[13]; 1357 int stream_mac = (sending ? (ssl->mac_flags & SSL_MAC_FLAG_WRITE_MAC_STREAM) 1358 : (ssl->mac_flags & SSL_MAC_FLAG_READ_MAC_STREAM)); 1359 int t; 1360 1361 if (sending) { 1362 seq = RECORD_LAYER_get_write_sequence(&ssl->rlayer); 1363 hash = ssl->write_hash; 1364 } else { 1365 seq = RECORD_LAYER_get_read_sequence(&ssl->rlayer); 1366 hash = ssl->read_hash; 1367 } 1368 1369 t = EVP_MD_CTX_size(hash); 1370 if (!ossl_assert(t >= 0)) 1371 return 0; 1372 md_size = t; 1373 1374 /* I should fix this up TLS TLS TLS TLS TLS XXXXXXXX */ 1375 if (stream_mac) { 1376 mac_ctx = hash; 1377 } else { 1378 hmac = EVP_MD_CTX_new(); 1379 if (hmac == NULL || !EVP_MD_CTX_copy(hmac, hash)) { 1380 EVP_MD_CTX_free(hmac); 1381 return 0; 1382 } 1383 mac_ctx = hmac; 1384 } 1385 1386 if (SSL_IS_DTLS(ssl)) { 1387 unsigned char dtlsseq[8], *p = dtlsseq; 1388 1389 s2n(sending ? DTLS_RECORD_LAYER_get_w_epoch(&ssl->rlayer) : 1390 DTLS_RECORD_LAYER_get_r_epoch(&ssl->rlayer), p); 1391 memcpy(p, &seq[2], 6); 1392 1393 memcpy(header, dtlsseq, 8); 1394 } else 1395 memcpy(header, seq, 8); 1396 1397 header[8] = rec->type; 1398 header[9] = (unsigned char)(ssl->version >> 8); 1399 header[10] = (unsigned char)(ssl->version); 1400 header[11] = (unsigned char)(rec->length >> 8); 1401 header[12] = (unsigned char)(rec->length & 0xff); 1402 1403 if (!sending && !SSL_READ_ETM(ssl) && 1404 EVP_CIPHER_CTX_mode(ssl->enc_read_ctx) == EVP_CIPH_CBC_MODE && 1405 ssl3_cbc_record_digest_supported(mac_ctx)) { 1406 /* 1407 * This is a CBC-encrypted record. We must avoid leaking any 1408 * timing-side channel information about how many blocks of data we 1409 * are hashing because that gives an attacker a timing-oracle. 1410 */ 1411 /* Final param == not SSLv3 */ 1412 if (ssl3_cbc_digest_record(mac_ctx, 1413 md, &md_size, 1414 header, rec->input, 1415 rec->length + md_size, rec->orig_len, 1416 ssl->s3->read_mac_secret, 1417 ssl->s3->read_mac_secret_size, 0) <= 0) { 1418 EVP_MD_CTX_free(hmac); 1419 return 0; 1420 } 1421 } else { 1422 /* TODO(size_t): Convert these calls */ 1423 if (EVP_DigestSignUpdate(mac_ctx, header, sizeof(header)) <= 0 1424 || EVP_DigestSignUpdate(mac_ctx, rec->input, rec->length) <= 0 1425 || EVP_DigestSignFinal(mac_ctx, md, &md_size) <= 0) { 1426 EVP_MD_CTX_free(hmac); 1427 return 0; 1428 } 1429 } 1430 1431 EVP_MD_CTX_free(hmac); 1432 1433 #ifdef SSL_DEBUG 1434 fprintf(stderr, "seq="); 1435 { 1436 int z; 1437 for (z = 0; z < 8; z++) 1438 fprintf(stderr, "%02X ", seq[z]); 1439 fprintf(stderr, "\n"); 1440 } 1441 fprintf(stderr, "rec="); 1442 { 1443 size_t z; 1444 for (z = 0; z < rec->length; z++) 1445 fprintf(stderr, "%02X ", rec->data[z]); 1446 fprintf(stderr, "\n"); 1447 } 1448 #endif 1449 1450 if (!SSL_IS_DTLS(ssl)) { 1451 for (i = 7; i >= 0; i--) { 1452 ++seq[i]; 1453 if (seq[i] != 0) 1454 break; 1455 } 1456 } 1457 #ifdef SSL_DEBUG 1458 { 1459 unsigned int z; 1460 for (z = 0; z < md_size; z++) 1461 fprintf(stderr, "%02X ", md[z]); 1462 fprintf(stderr, "\n"); 1463 } 1464 #endif 1465 return 1; 1466 } 1467 1468 /*- 1469 * ssl3_cbc_remove_padding removes padding from the decrypted, SSLv3, CBC 1470 * record in |rec| by updating |rec->length| in constant time. 1471 * 1472 * block_size: the block size of the cipher used to encrypt the record. 1473 * returns: 1474 * 0: (in non-constant time) if the record is publicly invalid. 1475 * 1: if the padding was valid 1476 * -1: otherwise. 1477 */ 1478 int ssl3_cbc_remove_padding(SSL3_RECORD *rec, 1479 size_t block_size, size_t mac_size) 1480 { 1481 size_t padding_length; 1482 size_t good; 1483 const size_t overhead = 1 /* padding length byte */ + mac_size; 1484 1485 /* 1486 * These lengths are all public so we can test them in non-constant time. 1487 */ 1488 if (overhead > rec->length) 1489 return 0; 1490 1491 padding_length = rec->data[rec->length - 1]; 1492 good = constant_time_ge_s(rec->length, padding_length + overhead); 1493 /* SSLv3 requires that the padding is minimal. */ 1494 good &= constant_time_ge_s(block_size, padding_length + 1); 1495 rec->length -= good & (padding_length + 1); 1496 return constant_time_select_int_s(good, 1, -1); 1497 } 1498 1499 /*- 1500 * tls1_cbc_remove_padding removes the CBC padding from the decrypted, TLS, CBC 1501 * record in |rec| in constant time and returns 1 if the padding is valid and 1502 * -1 otherwise. It also removes any explicit IV from the start of the record 1503 * without leaking any timing about whether there was enough space after the 1504 * padding was removed. 1505 * 1506 * block_size: the block size of the cipher used to encrypt the record. 1507 * returns: 1508 * 0: (in non-constant time) if the record is publicly invalid. 1509 * 1: if the padding was valid 1510 * -1: otherwise. 1511 */ 1512 int tls1_cbc_remove_padding(const SSL *s, 1513 SSL3_RECORD *rec, 1514 size_t block_size, size_t mac_size) 1515 { 1516 size_t good; 1517 size_t padding_length, to_check, i; 1518 const size_t overhead = 1 /* padding length byte */ + mac_size; 1519 /* Check if version requires explicit IV */ 1520 if (SSL_USE_EXPLICIT_IV(s)) { 1521 /* 1522 * These lengths are all public so we can test them in non-constant 1523 * time. 1524 */ 1525 if (overhead + block_size > rec->length) 1526 return 0; 1527 /* We can now safely skip explicit IV */ 1528 rec->data += block_size; 1529 rec->input += block_size; 1530 rec->length -= block_size; 1531 rec->orig_len -= block_size; 1532 } else if (overhead > rec->length) 1533 return 0; 1534 1535 padding_length = rec->data[rec->length - 1]; 1536 1537 if (EVP_CIPHER_flags(EVP_CIPHER_CTX_cipher(s->enc_read_ctx)) & 1538 EVP_CIPH_FLAG_AEAD_CIPHER) { 1539 /* padding is already verified */ 1540 rec->length -= padding_length + 1; 1541 return 1; 1542 } 1543 1544 good = constant_time_ge_s(rec->length, overhead + padding_length); 1545 /* 1546 * The padding consists of a length byte at the end of the record and 1547 * then that many bytes of padding, all with the same value as the length 1548 * byte. Thus, with the length byte included, there are i+1 bytes of 1549 * padding. We can't check just |padding_length+1| bytes because that 1550 * leaks decrypted information. Therefore we always have to check the 1551 * maximum amount of padding possible. (Again, the length of the record 1552 * is public information so we can use it.) 1553 */ 1554 to_check = 256; /* maximum amount of padding, inc length byte. */ 1555 if (to_check > rec->length) 1556 to_check = rec->length; 1557 1558 for (i = 0; i < to_check; i++) { 1559 unsigned char mask = constant_time_ge_8_s(padding_length, i); 1560 unsigned char b = rec->data[rec->length - 1 - i]; 1561 /* 1562 * The final |padding_length+1| bytes should all have the value 1563 * |padding_length|. Therefore the XOR should be zero. 1564 */ 1565 good &= ~(mask & (padding_length ^ b)); 1566 } 1567 1568 /* 1569 * If any of the final |padding_length+1| bytes had the wrong value, one 1570 * or more of the lower eight bits of |good| will be cleared. 1571 */ 1572 good = constant_time_eq_s(0xff, good & 0xff); 1573 rec->length -= good & (padding_length + 1); 1574 1575 return constant_time_select_int_s(good, 1, -1); 1576 } 1577 1578 /*- 1579 * ssl3_cbc_copy_mac copies |md_size| bytes from the end of |rec| to |out| in 1580 * constant time (independent of the concrete value of rec->length, which may 1581 * vary within a 256-byte window). 1582 * 1583 * ssl3_cbc_remove_padding or tls1_cbc_remove_padding must be called prior to 1584 * this function. 1585 * 1586 * On entry: 1587 * rec->orig_len >= md_size 1588 * md_size <= EVP_MAX_MD_SIZE 1589 * 1590 * If CBC_MAC_ROTATE_IN_PLACE is defined then the rotation is performed with 1591 * variable accesses in a 64-byte-aligned buffer. Assuming that this fits into 1592 * a single or pair of cache-lines, then the variable memory accesses don't 1593 * actually affect the timing. CPUs with smaller cache-lines [if any] are 1594 * not multi-core and are not considered vulnerable to cache-timing attacks. 1595 */ 1596 #define CBC_MAC_ROTATE_IN_PLACE 1597 1598 int ssl3_cbc_copy_mac(unsigned char *out, 1599 const SSL3_RECORD *rec, size_t md_size) 1600 { 1601 #if defined(CBC_MAC_ROTATE_IN_PLACE) 1602 unsigned char rotated_mac_buf[64 + EVP_MAX_MD_SIZE]; 1603 unsigned char *rotated_mac; 1604 char aux1, aux2, aux3, mask; 1605 #else 1606 unsigned char rotated_mac[EVP_MAX_MD_SIZE]; 1607 #endif 1608 1609 /* 1610 * mac_end is the index of |rec->data| just after the end of the MAC. 1611 */ 1612 size_t mac_end = rec->length; 1613 size_t mac_start = mac_end - md_size; 1614 size_t in_mac; 1615 /* 1616 * scan_start contains the number of bytes that we can ignore because the 1617 * MAC's position can only vary by 255 bytes. 1618 */ 1619 size_t scan_start = 0; 1620 size_t i, j; 1621 size_t rotate_offset; 1622 1623 if (!ossl_assert(rec->orig_len >= md_size 1624 && md_size <= EVP_MAX_MD_SIZE)) 1625 return 0; 1626 1627 #if defined(CBC_MAC_ROTATE_IN_PLACE) 1628 rotated_mac = rotated_mac_buf + ((0 - (size_t)rotated_mac_buf) & 63); 1629 #endif 1630 1631 /* This information is public so it's safe to branch based on it. */ 1632 if (rec->orig_len > md_size + 255 + 1) 1633 scan_start = rec->orig_len - (md_size + 255 + 1); 1634 1635 in_mac = 0; 1636 rotate_offset = 0; 1637 memset(rotated_mac, 0, md_size); 1638 for (i = scan_start, j = 0; i < rec->orig_len; i++) { 1639 size_t mac_started = constant_time_eq_s(i, mac_start); 1640 size_t mac_ended = constant_time_lt_s(i, mac_end); 1641 unsigned char b = rec->data[i]; 1642 1643 in_mac |= mac_started; 1644 in_mac &= mac_ended; 1645 rotate_offset |= j & mac_started; 1646 rotated_mac[j++] |= b & in_mac; 1647 j &= constant_time_lt_s(j, md_size); 1648 } 1649 1650 /* Now rotate the MAC */ 1651 #if defined(CBC_MAC_ROTATE_IN_PLACE) 1652 j = 0; 1653 for (i = 0; i < md_size; i++) { 1654 /* 1655 * in case cache-line is 32 bytes, 1656 * load from both lines and select appropriately 1657 */ 1658 aux1 = rotated_mac[rotate_offset & ~32]; 1659 aux2 = rotated_mac[rotate_offset | 32]; 1660 mask = constant_time_eq_8(rotate_offset & ~32, rotate_offset); 1661 aux3 = constant_time_select_8(mask, aux1, aux2); 1662 out[j++] = aux3; 1663 rotate_offset++; 1664 rotate_offset &= constant_time_lt_s(rotate_offset, md_size); 1665 } 1666 #else 1667 memset(out, 0, md_size); 1668 rotate_offset = md_size - rotate_offset; 1669 rotate_offset &= constant_time_lt_s(rotate_offset, md_size); 1670 for (i = 0; i < md_size; i++) { 1671 for (j = 0; j < md_size; j++) 1672 out[j] |= rotated_mac[i] & constant_time_eq_8_s(j, rotate_offset); 1673 rotate_offset++; 1674 rotate_offset &= constant_time_lt_s(rotate_offset, md_size); 1675 } 1676 #endif 1677 1678 return 1; 1679 } 1680 1681 int dtls1_process_record(SSL *s, DTLS1_BITMAP *bitmap) 1682 { 1683 int i; 1684 int enc_err; 1685 SSL_SESSION *sess; 1686 SSL3_RECORD *rr; 1687 int imac_size; 1688 size_t mac_size; 1689 unsigned char md[EVP_MAX_MD_SIZE]; 1690 size_t max_plain_length = SSL3_RT_MAX_PLAIN_LENGTH; 1691 1692 rr = RECORD_LAYER_get_rrec(&s->rlayer); 1693 sess = s->session; 1694 1695 /* 1696 * At this point, s->rlayer.packet_length == SSL3_RT_HEADER_LNGTH + rr->length, 1697 * and we have that many bytes in s->rlayer.packet 1698 */ 1699 rr->input = &(RECORD_LAYER_get_packet(&s->rlayer)[DTLS1_RT_HEADER_LENGTH]); 1700 1701 /* 1702 * ok, we can now read from 's->rlayer.packet' data into 'rr'. rr->input 1703 * points at rr->length bytes, which need to be copied into rr->data by 1704 * either the decryption or by the decompression. When the data is 'copied' 1705 * into the rr->data buffer, rr->input will be pointed at the new buffer 1706 */ 1707 1708 /* 1709 * We now have - encrypted [ MAC [ compressed [ plain ] ] ] rr->length 1710 * bytes of encrypted compressed stuff. 1711 */ 1712 1713 /* check is not needed I believe */ 1714 if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH) { 1715 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_DTLS1_PROCESS_RECORD, 1716 SSL_R_ENCRYPTED_LENGTH_TOO_LONG); 1717 return 0; 1718 } 1719 1720 /* decrypt in place in 'rr->input' */ 1721 rr->data = rr->input; 1722 rr->orig_len = rr->length; 1723 1724 if (SSL_READ_ETM(s) && s->read_hash) { 1725 unsigned char *mac; 1726 mac_size = EVP_MD_CTX_size(s->read_hash); 1727 if (!ossl_assert(mac_size <= EVP_MAX_MD_SIZE)) { 1728 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DTLS1_PROCESS_RECORD, 1729 ERR_R_INTERNAL_ERROR); 1730 return 0; 1731 } 1732 if (rr->orig_len < mac_size) { 1733 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_DTLS1_PROCESS_RECORD, 1734 SSL_R_LENGTH_TOO_SHORT); 1735 return 0; 1736 } 1737 rr->length -= mac_size; 1738 mac = rr->data + rr->length; 1739 i = s->method->ssl3_enc->mac(s, rr, md, 0 /* not send */ ); 1740 if (i == 0 || CRYPTO_memcmp(md, mac, (size_t)mac_size) != 0) { 1741 SSLfatal(s, SSL_AD_BAD_RECORD_MAC, SSL_F_DTLS1_PROCESS_RECORD, 1742 SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC); 1743 return 0; 1744 } 1745 } 1746 1747 enc_err = s->method->ssl3_enc->enc(s, rr, 1, 0); 1748 /*- 1749 * enc_err is: 1750 * 0: (in non-constant time) if the record is publicly invalid. 1751 * 1: if the padding is valid 1752 * -1: if the padding is invalid 1753 */ 1754 if (enc_err == 0) { 1755 if (ossl_statem_in_error(s)) { 1756 /* SSLfatal() got called */ 1757 return 0; 1758 } 1759 /* For DTLS we simply ignore bad packets. */ 1760 rr->length = 0; 1761 RECORD_LAYER_reset_packet_length(&s->rlayer); 1762 return 0; 1763 } 1764 #ifdef SSL_DEBUG 1765 printf("dec %ld\n", rr->length); 1766 { 1767 size_t z; 1768 for (z = 0; z < rr->length; z++) 1769 printf("%02X%c", rr->data[z], ((z + 1) % 16) ? ' ' : '\n'); 1770 } 1771 printf("\n"); 1772 #endif 1773 1774 /* r->length is now the compressed data plus mac */ 1775 if ((sess != NULL) && !SSL_READ_ETM(s) && 1776 (s->enc_read_ctx != NULL) && (EVP_MD_CTX_md(s->read_hash) != NULL)) { 1777 /* s->read_hash != NULL => mac_size != -1 */ 1778 unsigned char *mac = NULL; 1779 unsigned char mac_tmp[EVP_MAX_MD_SIZE]; 1780 1781 /* TODO(size_t): Convert this to do size_t properly */ 1782 imac_size = EVP_MD_CTX_size(s->read_hash); 1783 if (imac_size < 0) { 1784 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DTLS1_PROCESS_RECORD, 1785 ERR_LIB_EVP); 1786 return 0; 1787 } 1788 mac_size = (size_t)imac_size; 1789 if (!ossl_assert(mac_size <= EVP_MAX_MD_SIZE)) { 1790 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DTLS1_PROCESS_RECORD, 1791 ERR_R_INTERNAL_ERROR); 1792 return 0; 1793 } 1794 1795 /* 1796 * orig_len is the length of the record before any padding was 1797 * removed. This is public information, as is the MAC in use, 1798 * therefore we can safely process the record in a different amount 1799 * of time if it's too short to possibly contain a MAC. 1800 */ 1801 if (rr->orig_len < mac_size || 1802 /* CBC records must have a padding length byte too. */ 1803 (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE && 1804 rr->orig_len < mac_size + 1)) { 1805 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_DTLS1_PROCESS_RECORD, 1806 SSL_R_LENGTH_TOO_SHORT); 1807 return 0; 1808 } 1809 1810 if (EVP_CIPHER_CTX_mode(s->enc_read_ctx) == EVP_CIPH_CBC_MODE) { 1811 /* 1812 * We update the length so that the TLS header bytes can be 1813 * constructed correctly but we need to extract the MAC in 1814 * constant time from within the record, without leaking the 1815 * contents of the padding bytes. 1816 */ 1817 mac = mac_tmp; 1818 if (!ssl3_cbc_copy_mac(mac_tmp, rr, mac_size)) { 1819 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_DTLS1_PROCESS_RECORD, 1820 ERR_R_INTERNAL_ERROR); 1821 return 0; 1822 } 1823 rr->length -= mac_size; 1824 } else { 1825 /* 1826 * In this case there's no padding, so |rec->orig_len| equals 1827 * |rec->length| and we checked that there's enough bytes for 1828 * |mac_size| above. 1829 */ 1830 rr->length -= mac_size; 1831 mac = &rr->data[rr->length]; 1832 } 1833 1834 i = s->method->ssl3_enc->mac(s, rr, md, 0 /* not send */ ); 1835 if (i == 0 || mac == NULL 1836 || CRYPTO_memcmp(md, mac, mac_size) != 0) 1837 enc_err = -1; 1838 if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH + mac_size) 1839 enc_err = -1; 1840 } 1841 1842 if (enc_err < 0) { 1843 /* decryption failed, silently discard message */ 1844 rr->length = 0; 1845 RECORD_LAYER_reset_packet_length(&s->rlayer); 1846 return 0; 1847 } 1848 1849 /* r->length is now just compressed */ 1850 if (s->expand != NULL) { 1851 if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH) { 1852 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_DTLS1_PROCESS_RECORD, 1853 SSL_R_COMPRESSED_LENGTH_TOO_LONG); 1854 return 0; 1855 } 1856 if (!ssl3_do_uncompress(s, rr)) { 1857 SSLfatal(s, SSL_AD_DECOMPRESSION_FAILURE, 1858 SSL_F_DTLS1_PROCESS_RECORD, SSL_R_BAD_DECOMPRESSION); 1859 return 0; 1860 } 1861 } 1862 1863 /* use current Max Fragment Length setting if applicable */ 1864 if (s->session != NULL && USE_MAX_FRAGMENT_LENGTH_EXT(s->session)) 1865 max_plain_length = GET_MAX_FRAGMENT_LENGTH(s->session); 1866 1867 /* send overflow if the plaintext is too long now it has passed MAC */ 1868 if (rr->length > max_plain_length) { 1869 SSLfatal(s, SSL_AD_RECORD_OVERFLOW, SSL_F_DTLS1_PROCESS_RECORD, 1870 SSL_R_DATA_LENGTH_TOO_LONG); 1871 return 0; 1872 } 1873 1874 rr->off = 0; 1875 /*- 1876 * So at this point the following is true 1877 * ssl->s3->rrec.type is the type of record 1878 * ssl->s3->rrec.length == number of bytes in record 1879 * ssl->s3->rrec.off == offset to first valid byte 1880 * ssl->s3->rrec.data == where to take bytes from, increment 1881 * after use :-). 1882 */ 1883 1884 /* we have pulled in a full packet so zero things */ 1885 RECORD_LAYER_reset_packet_length(&s->rlayer); 1886 1887 /* Mark receipt of record. */ 1888 dtls1_record_bitmap_update(s, bitmap); 1889 1890 return 1; 1891 } 1892 1893 /* 1894 * Retrieve a buffered record that belongs to the current epoch, i.e. processed 1895 */ 1896 #define dtls1_get_processed_record(s) \ 1897 dtls1_retrieve_buffered_record((s), \ 1898 &(DTLS_RECORD_LAYER_get_processed_rcds(&s->rlayer))) 1899 1900 /*- 1901 * Call this to get a new input record. 1902 * It will return <= 0 if more data is needed, normally due to an error 1903 * or non-blocking IO. 1904 * When it finishes, one packet has been decoded and can be found in 1905 * ssl->s3->rrec.type - is the type of record 1906 * ssl->s3->rrec.data, - data 1907 * ssl->s3->rrec.length, - number of bytes 1908 */ 1909 /* used only by dtls1_read_bytes */ 1910 int dtls1_get_record(SSL *s) 1911 { 1912 int ssl_major, ssl_minor; 1913 int rret; 1914 size_t more, n; 1915 SSL3_RECORD *rr; 1916 unsigned char *p = NULL; 1917 unsigned short version; 1918 DTLS1_BITMAP *bitmap; 1919 unsigned int is_next_epoch; 1920 1921 rr = RECORD_LAYER_get_rrec(&s->rlayer); 1922 1923 again: 1924 /* 1925 * The epoch may have changed. If so, process all the pending records. 1926 * This is a non-blocking operation. 1927 */ 1928 if (!dtls1_process_buffered_records(s)) { 1929 /* SSLfatal() already called */ 1930 return -1; 1931 } 1932 1933 /* if we're renegotiating, then there may be buffered records */ 1934 if (dtls1_get_processed_record(s)) 1935 return 1; 1936 1937 /* get something from the wire */ 1938 1939 /* check if we have the header */ 1940 if ((RECORD_LAYER_get_rstate(&s->rlayer) != SSL_ST_READ_BODY) || 1941 (RECORD_LAYER_get_packet_length(&s->rlayer) < DTLS1_RT_HEADER_LENGTH)) { 1942 rret = ssl3_read_n(s, DTLS1_RT_HEADER_LENGTH, 1943 SSL3_BUFFER_get_len(&s->rlayer.rbuf), 0, 1, &n); 1944 /* read timeout is handled by dtls1_read_bytes */ 1945 if (rret <= 0) { 1946 /* SSLfatal() already called if appropriate */ 1947 return rret; /* error or non-blocking */ 1948 } 1949 1950 /* this packet contained a partial record, dump it */ 1951 if (RECORD_LAYER_get_packet_length(&s->rlayer) != 1952 DTLS1_RT_HEADER_LENGTH) { 1953 RECORD_LAYER_reset_packet_length(&s->rlayer); 1954 goto again; 1955 } 1956 1957 RECORD_LAYER_set_rstate(&s->rlayer, SSL_ST_READ_BODY); 1958 1959 p = RECORD_LAYER_get_packet(&s->rlayer); 1960 1961 if (s->msg_callback) 1962 s->msg_callback(0, 0, SSL3_RT_HEADER, p, DTLS1_RT_HEADER_LENGTH, 1963 s, s->msg_callback_arg); 1964 1965 /* Pull apart the header into the DTLS1_RECORD */ 1966 rr->type = *(p++); 1967 ssl_major = *(p++); 1968 ssl_minor = *(p++); 1969 version = (ssl_major << 8) | ssl_minor; 1970 1971 /* sequence number is 64 bits, with top 2 bytes = epoch */ 1972 n2s(p, rr->epoch); 1973 1974 memcpy(&(RECORD_LAYER_get_read_sequence(&s->rlayer)[2]), p, 6); 1975 p += 6; 1976 1977 n2s(p, rr->length); 1978 rr->read = 0; 1979 1980 /* 1981 * Lets check the version. We tolerate alerts that don't have the exact 1982 * version number (e.g. because of protocol version errors) 1983 */ 1984 if (!s->first_packet && rr->type != SSL3_RT_ALERT) { 1985 if (version != s->version) { 1986 /* unexpected version, silently discard */ 1987 rr->length = 0; 1988 rr->read = 1; 1989 RECORD_LAYER_reset_packet_length(&s->rlayer); 1990 goto again; 1991 } 1992 } 1993 1994 if ((version & 0xff00) != (s->version & 0xff00)) { 1995 /* wrong version, silently discard record */ 1996 rr->length = 0; 1997 rr->read = 1; 1998 RECORD_LAYER_reset_packet_length(&s->rlayer); 1999 goto again; 2000 } 2001 2002 if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH) { 2003 /* record too long, silently discard it */ 2004 rr->length = 0; 2005 rr->read = 1; 2006 RECORD_LAYER_reset_packet_length(&s->rlayer); 2007 goto again; 2008 } 2009 2010 /* If received packet overflows own-client Max Fragment Length setting */ 2011 if (s->session != NULL && USE_MAX_FRAGMENT_LENGTH_EXT(s->session) 2012 && rr->length > GET_MAX_FRAGMENT_LENGTH(s->session) + SSL3_RT_MAX_ENCRYPTED_OVERHEAD) { 2013 /* record too long, silently discard it */ 2014 rr->length = 0; 2015 rr->read = 1; 2016 RECORD_LAYER_reset_packet_length(&s->rlayer); 2017 goto again; 2018 } 2019 2020 /* now s->rlayer.rstate == SSL_ST_READ_BODY */ 2021 } 2022 2023 /* s->rlayer.rstate == SSL_ST_READ_BODY, get and decode the data */ 2024 2025 if (rr->length > 2026 RECORD_LAYER_get_packet_length(&s->rlayer) - DTLS1_RT_HEADER_LENGTH) { 2027 /* now s->rlayer.packet_length == DTLS1_RT_HEADER_LENGTH */ 2028 more = rr->length; 2029 rret = ssl3_read_n(s, more, more, 1, 1, &n); 2030 /* this packet contained a partial record, dump it */ 2031 if (rret <= 0 || n != more) { 2032 if (ossl_statem_in_error(s)) { 2033 /* ssl3_read_n() called SSLfatal() */ 2034 return -1; 2035 } 2036 rr->length = 0; 2037 rr->read = 1; 2038 RECORD_LAYER_reset_packet_length(&s->rlayer); 2039 goto again; 2040 } 2041 2042 /* 2043 * now n == rr->length, and s->rlayer.packet_length == 2044 * DTLS1_RT_HEADER_LENGTH + rr->length 2045 */ 2046 } 2047 /* set state for later operations */ 2048 RECORD_LAYER_set_rstate(&s->rlayer, SSL_ST_READ_HEADER); 2049 2050 /* match epochs. NULL means the packet is dropped on the floor */ 2051 bitmap = dtls1_get_bitmap(s, rr, &is_next_epoch); 2052 if (bitmap == NULL) { 2053 rr->length = 0; 2054 RECORD_LAYER_reset_packet_length(&s->rlayer); /* dump this record */ 2055 goto again; /* get another record */ 2056 } 2057 #ifndef OPENSSL_NO_SCTP 2058 /* Only do replay check if no SCTP bio */ 2059 if (!BIO_dgram_is_sctp(SSL_get_rbio(s))) { 2060 #endif 2061 /* Check whether this is a repeat, or aged record. */ 2062 /* 2063 * TODO: Does it make sense to have replay protection in epoch 0 where 2064 * we have no integrity negotiated yet? 2065 */ 2066 if (!dtls1_record_replay_check(s, bitmap)) { 2067 rr->length = 0; 2068 rr->read = 1; 2069 RECORD_LAYER_reset_packet_length(&s->rlayer); /* dump this record */ 2070 goto again; /* get another record */ 2071 } 2072 #ifndef OPENSSL_NO_SCTP 2073 } 2074 #endif 2075 2076 /* just read a 0 length packet */ 2077 if (rr->length == 0) { 2078 rr->read = 1; 2079 goto again; 2080 } 2081 2082 /* 2083 * If this record is from the next epoch (either HM or ALERT), and a 2084 * handshake is currently in progress, buffer it since it cannot be 2085 * processed at this time. 2086 */ 2087 if (is_next_epoch) { 2088 if ((SSL_in_init(s) || ossl_statem_get_in_handshake(s))) { 2089 if (dtls1_buffer_record (s, 2090 &(DTLS_RECORD_LAYER_get_unprocessed_rcds(&s->rlayer)), 2091 rr->seq_num) < 0) { 2092 /* SSLfatal() already called */ 2093 return -1; 2094 } 2095 } 2096 rr->length = 0; 2097 rr->read = 1; 2098 RECORD_LAYER_reset_packet_length(&s->rlayer); 2099 goto again; 2100 } 2101 2102 if (!dtls1_process_record(s, bitmap)) { 2103 if (ossl_statem_in_error(s)) { 2104 /* dtls1_process_record() called SSLfatal */ 2105 return -1; 2106 } 2107 rr->length = 0; 2108 rr->read = 1; 2109 RECORD_LAYER_reset_packet_length(&s->rlayer); /* dump this record */ 2110 goto again; /* get another record */ 2111 } 2112 2113 return 1; 2114 2115 } 2116 2117 int dtls_buffer_listen_record(SSL *s, size_t len, unsigned char *seq, size_t off) 2118 { 2119 SSL3_RECORD *rr; 2120 2121 rr = RECORD_LAYER_get_rrec(&s->rlayer); 2122 memset(rr, 0, sizeof(SSL3_RECORD)); 2123 2124 rr->length = len; 2125 rr->type = SSL3_RT_HANDSHAKE; 2126 memcpy(rr->seq_num, seq, sizeof(rr->seq_num)); 2127 rr->off = off; 2128 2129 s->rlayer.packet = RECORD_LAYER_get_rbuf(&s->rlayer)->buf; 2130 s->rlayer.packet_length = DTLS1_RT_HEADER_LENGTH + len; 2131 rr->data = s->rlayer.packet + DTLS1_RT_HEADER_LENGTH; 2132 2133 if (dtls1_buffer_record(s, &(s->rlayer.d->processed_rcds), 2134 SSL3_RECORD_get_seq_num(s->rlayer.rrec)) <= 0) { 2135 /* SSLfatal() already called */ 2136 return 0; 2137 } 2138 2139 return 1; 2140 } 2141