1 /* Copyright (C) 1995-1998 Eric Young (eay (at) cryptsoft.com) 2 * All rights reserved. 3 * 4 * This package is an SSL implementation written 5 * by Eric Young (eay (at) cryptsoft.com). 6 * The implementation was written so as to conform with Netscapes SSL. 7 * 8 * This library is free for commercial and non-commercial use as long as 9 * the following conditions are aheared to. The following conditions 10 * apply to all code found in this distribution, be it the RC4, RSA, 11 * lhash, DES, etc., code; not just the SSL code. The SSL documentation 12 * included with this distribution is covered by the same copyright terms 13 * except that the holder is Tim Hudson (tjh (at) cryptsoft.com). 14 * 15 * Copyright remains Eric Young's, and as such any Copyright notices in 16 * the code are not to be removed. 17 * If this package is used in a product, Eric Young should be given attribution 18 * as the author of the parts of the library used. 19 * This can be in the form of a textual message at program startup or 20 * in documentation (online or textual) provided with the package. 21 * 22 * Redistribution and use in source and binary forms, with or without 23 * modification, are permitted provided that the following conditions 24 * are met: 25 * 1. Redistributions of source code must retain the copyright 26 * notice, this list of conditions and the following disclaimer. 27 * 2. Redistributions in binary form must reproduce the above copyright 28 * notice, this list of conditions and the following disclaimer in the 29 * documentation and/or other materials provided with the distribution. 30 * 3. All advertising materials mentioning features or use of this software 31 * must display the following acknowledgement: 32 * "This product includes cryptographic software written by 33 * Eric Young (eay (at) cryptsoft.com)" 34 * The word 'cryptographic' can be left out if the rouines from the library 35 * being used are not cryptographic related :-). 36 * 4. If you include any Windows specific code (or a derivative thereof) from 37 * the apps directory (application code) you must include an acknowledgement: 38 * "This product includes software written by Tim Hudson (tjh (at) cryptsoft.com)" 39 * 40 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND 41 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 43 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 44 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 45 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 46 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 48 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 49 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 50 * SUCH DAMAGE. 51 * 52 * The licence and distribution terms for any publically available version or 53 * derivative of this code cannot be changed. i.e. this code cannot simply be 54 * copied and put under another distribution licence 55 * [including the GNU Public Licence.] 56 */ 57 /* ==================================================================== 58 * Copyright (c) 1998-2002 The OpenSSL Project. All rights reserved. 59 * 60 * Redistribution and use in source and binary forms, with or without 61 * modification, are permitted provided that the following conditions 62 * are met: 63 * 64 * 1. Redistributions of source code must retain the above copyright 65 * notice, this list of conditions and the following disclaimer. 66 * 67 * 2. Redistributions in binary form must reproduce the above copyright 68 * notice, this list of conditions and the following disclaimer in 69 * the documentation and/or other materials provided with the 70 * distribution. 71 * 72 * 3. All advertising materials mentioning features or use of this 73 * software must display the following acknowledgment: 74 * "This product includes software developed by the OpenSSL Project 75 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" 76 * 77 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to 78 * endorse or promote products derived from this software without 79 * prior written permission. For written permission, please contact 80 * openssl-core (at) openssl.org. 81 * 82 * 5. Products derived from this software may not be called "OpenSSL" 83 * nor may "OpenSSL" appear in their names without prior written 84 * permission of the OpenSSL Project. 85 * 86 * 6. Redistributions of any form whatsoever must retain the following 87 * acknowledgment: 88 * "This product includes software developed by the OpenSSL Project 89 * for use in the OpenSSL Toolkit (http://www.openssl.org/)" 90 * 91 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY 92 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 93 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 94 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR 95 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 96 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 97 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 98 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 99 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 100 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 101 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 102 * OF THE POSSIBILITY OF SUCH DAMAGE. 103 * ==================================================================== 104 * 105 * This product includes cryptographic software written by Eric Young 106 * (eay (at) cryptsoft.com). This product includes software written by Tim 107 * Hudson (tjh (at) cryptsoft.com). */ 108 109 #include <openssl/ssl.h> 110 111 #include <assert.h> 112 #include <string.h> 113 114 #include <openssl/bytestring.h> 115 #include <openssl/err.h> 116 #include <openssl/mem.h> 117 118 #include "internal.h" 119 #include "../crypto/internal.h" 120 121 122 /* kMaxEmptyRecords is the number of consecutive, empty records that will be 123 * processed. Without this limit an attacker could send empty records at a 124 * faster rate than we can process and cause record processing to loop 125 * forever. */ 126 static const uint8_t kMaxEmptyRecords = 32; 127 128 /* kMaxEarlyDataSkipped is the maximum number of rejected early data bytes that 129 * will be skipped. Without this limit an attacker could send records at a 130 * faster rate than we can process and cause trial decryption to loop forever. 131 * This value should be slightly above kMaxEarlyDataAccepted, which is measured 132 * in plaintext. */ 133 static const size_t kMaxEarlyDataSkipped = 16384; 134 135 /* kMaxWarningAlerts is the number of consecutive warning alerts that will be 136 * processed. */ 137 static const uint8_t kMaxWarningAlerts = 4; 138 139 /* ssl_needs_record_splitting returns one if |ssl|'s current outgoing cipher 140 * state needs record-splitting and zero otherwise. */ 141 static int ssl_needs_record_splitting(const SSL *ssl) { 142 #if !defined(BORINGSSL_UNSAFE_FUZZER_MODE) 143 return ssl->s3->aead_write_ctx != NULL && 144 ssl->s3->aead_write_ctx->version < TLS1_1_VERSION && 145 (ssl->mode & SSL_MODE_CBC_RECORD_SPLITTING) != 0 && 146 SSL_CIPHER_is_block_cipher(ssl->s3->aead_write_ctx->cipher); 147 #else 148 return 0; 149 #endif 150 } 151 152 int ssl_record_sequence_update(uint8_t *seq, size_t seq_len) { 153 for (size_t i = seq_len - 1; i < seq_len; i--) { 154 ++seq[i]; 155 if (seq[i] != 0) { 156 return 1; 157 } 158 } 159 OPENSSL_PUT_ERROR(SSL, ERR_R_OVERFLOW); 160 return 0; 161 } 162 163 size_t ssl_record_prefix_len(const SSL *ssl) { 164 size_t header_len; 165 if (SSL_is_dtls(ssl)) { 166 header_len = DTLS1_RT_HEADER_LENGTH; 167 } else { 168 header_len = SSL3_RT_HEADER_LENGTH; 169 } 170 171 return header_len + SSL_AEAD_CTX_explicit_nonce_len(ssl->s3->aead_read_ctx); 172 } 173 174 size_t ssl_seal_align_prefix_len(const SSL *ssl) { 175 if (SSL_is_dtls(ssl)) { 176 return DTLS1_RT_HEADER_LENGTH + 177 SSL_AEAD_CTX_explicit_nonce_len(ssl->s3->aead_write_ctx); 178 } 179 180 size_t ret = SSL3_RT_HEADER_LENGTH + 181 SSL_AEAD_CTX_explicit_nonce_len(ssl->s3->aead_write_ctx); 182 if (ssl_needs_record_splitting(ssl)) { 183 ret += SSL3_RT_HEADER_LENGTH; 184 ret += ssl_cipher_get_record_split_len(ssl->s3->aead_write_ctx->cipher); 185 } 186 return ret; 187 } 188 189 size_t SSL_max_seal_overhead(const SSL *ssl) { 190 if (SSL_is_dtls(ssl)) { 191 return dtls_max_seal_overhead(ssl, dtls1_use_current_epoch); 192 } 193 194 size_t ret = SSL3_RT_HEADER_LENGTH; 195 ret += SSL_AEAD_CTX_max_overhead(ssl->s3->aead_write_ctx); 196 /* TLS 1.3 needs an extra byte for the encrypted record type. */ 197 if (ssl->s3->aead_write_ctx != NULL && 198 ssl->s3->aead_write_ctx->version >= TLS1_3_VERSION) { 199 ret += 1; 200 } 201 if (ssl_needs_record_splitting(ssl)) { 202 ret *= 2; 203 } 204 return ret; 205 } 206 207 enum ssl_open_record_t tls_open_record(SSL *ssl, uint8_t *out_type, CBS *out, 208 size_t *out_consumed, uint8_t *out_alert, 209 uint8_t *in, size_t in_len) { 210 *out_consumed = 0; 211 212 CBS cbs; 213 CBS_init(&cbs, in, in_len); 214 215 /* Decode the record header. */ 216 uint8_t type; 217 uint16_t version, ciphertext_len; 218 if (!CBS_get_u8(&cbs, &type) || 219 !CBS_get_u16(&cbs, &version) || 220 !CBS_get_u16(&cbs, &ciphertext_len)) { 221 *out_consumed = SSL3_RT_HEADER_LENGTH; 222 return ssl_open_record_partial; 223 } 224 225 int version_ok; 226 if (ssl->s3->aead_read_ctx == NULL) { 227 /* Only check the first byte. Enforcing beyond that can prevent decoding 228 * version negotiation failure alerts. */ 229 version_ok = (version >> 8) == SSL3_VERSION_MAJOR; 230 } else if (ssl3_protocol_version(ssl) < TLS1_3_VERSION) { 231 /* Earlier versions of TLS switch the record version. */ 232 version_ok = version == ssl->version; 233 } else { 234 /* Starting TLS 1.3, the version field is frozen at {3, 1}. */ 235 version_ok = version == TLS1_VERSION; 236 } 237 238 if (!version_ok) { 239 OPENSSL_PUT_ERROR(SSL, SSL_R_WRONG_VERSION_NUMBER); 240 *out_alert = SSL_AD_PROTOCOL_VERSION; 241 return ssl_open_record_error; 242 } 243 244 /* Check the ciphertext length. */ 245 if (ciphertext_len > SSL3_RT_MAX_ENCRYPTED_LENGTH) { 246 OPENSSL_PUT_ERROR(SSL, SSL_R_ENCRYPTED_LENGTH_TOO_LONG); 247 *out_alert = SSL_AD_RECORD_OVERFLOW; 248 return ssl_open_record_error; 249 } 250 251 /* Extract the body. */ 252 CBS body; 253 if (!CBS_get_bytes(&cbs, &body, ciphertext_len)) { 254 *out_consumed = SSL3_RT_HEADER_LENGTH + (size_t)ciphertext_len; 255 return ssl_open_record_partial; 256 } 257 258 ssl_do_msg_callback(ssl, 0 /* read */, SSL3_RT_HEADER, in, 259 SSL3_RT_HEADER_LENGTH); 260 261 *out_consumed = in_len - CBS_len(&cbs); 262 263 /* Skip early data received when expecting a second ClientHello if we rejected 264 * 0RTT. */ 265 if (ssl->s3->skip_early_data && 266 ssl->s3->aead_read_ctx == NULL && 267 type == SSL3_RT_APPLICATION_DATA) { 268 goto skipped_data; 269 } 270 271 /* Decrypt the body in-place. */ 272 if (!SSL_AEAD_CTX_open(ssl->s3->aead_read_ctx, out, type, version, 273 ssl->s3->read_sequence, (uint8_t *)CBS_data(&body), 274 CBS_len(&body))) { 275 if (ssl->s3->skip_early_data && 276 ssl->s3->aead_read_ctx != NULL) { 277 ERR_clear_error(); 278 goto skipped_data; 279 } 280 281 OPENSSL_PUT_ERROR(SSL, SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC); 282 *out_alert = SSL_AD_BAD_RECORD_MAC; 283 return ssl_open_record_error; 284 } 285 286 ssl->s3->skip_early_data = 0; 287 288 if (!ssl_record_sequence_update(ssl->s3->read_sequence, 8)) { 289 *out_alert = SSL_AD_INTERNAL_ERROR; 290 return ssl_open_record_error; 291 } 292 293 /* TLS 1.3 hides the record type inside the encrypted data. */ 294 if (ssl->s3->aead_read_ctx != NULL && 295 ssl->s3->aead_read_ctx->version >= TLS1_3_VERSION) { 296 /* The outer record type is always application_data. */ 297 if (type != SSL3_RT_APPLICATION_DATA) { 298 OPENSSL_PUT_ERROR(SSL, SSL_R_INVALID_OUTER_RECORD_TYPE); 299 *out_alert = SSL_AD_DECODE_ERROR; 300 return ssl_open_record_error; 301 } 302 303 do { 304 if (!CBS_get_last_u8(out, &type)) { 305 OPENSSL_PUT_ERROR(SSL, SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC); 306 *out_alert = SSL_AD_DECRYPT_ERROR; 307 return ssl_open_record_error; 308 } 309 } while (type == 0); 310 } 311 312 /* Check the plaintext length. */ 313 if (CBS_len(out) > SSL3_RT_MAX_PLAIN_LENGTH) { 314 OPENSSL_PUT_ERROR(SSL, SSL_R_DATA_LENGTH_TOO_LONG); 315 *out_alert = SSL_AD_RECORD_OVERFLOW; 316 return ssl_open_record_error; 317 } 318 319 /* Limit the number of consecutive empty records. */ 320 if (CBS_len(out) == 0) { 321 ssl->s3->empty_record_count++; 322 if (ssl->s3->empty_record_count > kMaxEmptyRecords) { 323 OPENSSL_PUT_ERROR(SSL, SSL_R_TOO_MANY_EMPTY_FRAGMENTS); 324 *out_alert = SSL_AD_UNEXPECTED_MESSAGE; 325 return ssl_open_record_error; 326 } 327 /* Apart from the limit, empty records are returned up to the caller. This 328 * allows the caller to reject records of the wrong type. */ 329 } else { 330 ssl->s3->empty_record_count = 0; 331 } 332 333 if (type == SSL3_RT_ALERT) { 334 /* Return end_of_early_data alerts as-is for the caller to process. */ 335 if (CBS_len(out) == 2 && 336 CBS_data(out)[0] == SSL3_AL_WARNING && 337 CBS_data(out)[1] == TLS1_AD_END_OF_EARLY_DATA) { 338 *out_type = type; 339 return ssl_open_record_success; 340 } 341 342 return ssl_process_alert(ssl, out_alert, CBS_data(out), CBS_len(out)); 343 } 344 345 ssl->s3->warning_alert_count = 0; 346 347 *out_type = type; 348 return ssl_open_record_success; 349 350 skipped_data: 351 ssl->s3->early_data_skipped += *out_consumed; 352 if (ssl->s3->early_data_skipped < *out_consumed) { 353 ssl->s3->early_data_skipped = kMaxEarlyDataSkipped + 1; 354 } 355 356 if (ssl->s3->early_data_skipped > kMaxEarlyDataSkipped) { 357 OPENSSL_PUT_ERROR(SSL, SSL_R_TOO_MUCH_SKIPPED_EARLY_DATA); 358 *out_alert = SSL_AD_UNEXPECTED_MESSAGE; 359 return ssl_open_record_error; 360 } 361 362 return ssl_open_record_discard; 363 } 364 365 static int do_seal_record(SSL *ssl, uint8_t *out_prefix, uint8_t *out, 366 uint8_t *out_suffix, size_t *out_suffix_len, 367 const size_t max_out_suffix_len, uint8_t type, 368 const uint8_t *in, const size_t in_len) { 369 assert(in == out || !buffers_alias(in, in_len, out, in_len)); 370 assert(!buffers_alias(in, in_len, out_prefix, ssl_record_prefix_len(ssl))); 371 assert(!buffers_alias(in, in_len, out_suffix, max_out_suffix_len)); 372 373 /* TLS 1.3 hides the actual record type inside the encrypted data. */ 374 uint8_t *extra_in = NULL; 375 size_t extra_in_len = 0; 376 if (ssl->s3->aead_write_ctx != NULL && 377 ssl->s3->aead_write_ctx->version >= TLS1_3_VERSION) { 378 extra_in = &type; 379 extra_in_len = 1; 380 out_prefix[0] = SSL3_RT_APPLICATION_DATA; 381 } else { 382 out_prefix[0] = type; 383 } 384 385 /* The TLS record-layer version number is meaningless and, starting in 386 * TLS 1.3, is frozen at TLS 1.0. But for historical reasons, SSL 3.0 387 * ClientHellos should use SSL 3.0 and pre-TLS-1.3 expects the version 388 * to change after version negotiation. */ 389 uint16_t wire_version = TLS1_VERSION; 390 if (ssl->s3->hs != NULL && ssl->s3->hs->max_version == SSL3_VERSION) { 391 wire_version = SSL3_VERSION; 392 } 393 if (ssl->s3->have_version && ssl3_protocol_version(ssl) < TLS1_3_VERSION) { 394 wire_version = ssl->version; 395 } 396 out_prefix[1] = wire_version >> 8; 397 out_prefix[2] = wire_version & 0xff; 398 399 /* Write the ciphertext, leaving two bytes for the length. */ 400 if (!SSL_AEAD_CTX_seal_scatter( 401 ssl->s3->aead_write_ctx, out_prefix + SSL3_RT_HEADER_LENGTH, out, 402 out_suffix, out_suffix_len, max_out_suffix_len, type, wire_version, 403 ssl->s3->write_sequence, in, in_len, extra_in, extra_in_len) || 404 !ssl_record_sequence_update(ssl->s3->write_sequence, 8)) { 405 return 0; 406 } 407 408 /* Fill in the length. */ 409 const size_t ciphertext_len = 410 SSL_AEAD_CTX_explicit_nonce_len(ssl->s3->aead_write_ctx) + in_len + 411 *out_suffix_len; 412 if (ciphertext_len >= 1 << 15) { 413 OPENSSL_PUT_ERROR(SSL, ERR_R_OVERFLOW); 414 return 0; 415 } 416 out_prefix[3] = ciphertext_len >> 8; 417 out_prefix[4] = ciphertext_len & 0xff; 418 419 ssl_do_msg_callback(ssl, 1 /* write */, SSL3_RT_HEADER, out_prefix, 420 SSL3_RT_HEADER_LENGTH); 421 return 1; 422 } 423 424 static size_t tls_seal_scatter_prefix_len(const SSL *ssl, uint8_t type, 425 size_t in_len) { 426 size_t ret = SSL3_RT_HEADER_LENGTH; 427 if (type == SSL3_RT_APPLICATION_DATA && in_len > 1 && 428 ssl_needs_record_splitting(ssl)) { 429 /* In the case of record splitting, the 1-byte record (of the 1/n-1 split) 430 * will be placed in the prefix, as will four of the five bytes of the 431 * record header for the main record. The final byte will replace the first 432 * byte of the plaintext that was used in the small record. */ 433 ret += ssl_cipher_get_record_split_len(ssl->s3->aead_write_ctx->cipher); 434 ret += SSL3_RT_HEADER_LENGTH - 1; 435 } else { 436 ret += SSL_AEAD_CTX_explicit_nonce_len(ssl->s3->aead_write_ctx); 437 } 438 return ret; 439 } 440 441 /* tls_seal_scatter_record seals a new record of type |type| and body |in| and 442 * splits it between |out_prefix|, |out|, and |out_suffix|. Exactly 443 * |tls_seal_scatter_prefix_len| bytes are written to |out_prefix|, |in_len| 444 * bytes to |out|, and up to 1 + |SSL_AEAD_CTX_max_overhead| bytes to 445 * |out_suffix|. |*out_suffix_len| is set to the actual number of bytes written 446 * to |out_suffix|. It returns one on success and zero on error. If enabled, 447 * |tls_seal_scatter_record| implements TLS 1.0 CBC 1/n-1 record splitting and 448 * may write two records concatenated. */ 449 static int tls_seal_scatter_record(SSL *ssl, uint8_t *out_prefix, uint8_t *out, 450 uint8_t *out_suffix, size_t *out_suffix_len, 451 size_t max_out_suffix_len, uint8_t type, 452 const uint8_t *in, size_t in_len) { 453 if (type == SSL3_RT_APPLICATION_DATA && in_len > 1 && 454 ssl_needs_record_splitting(ssl)) { 455 assert(SSL_AEAD_CTX_explicit_nonce_len(ssl->s3->aead_write_ctx) == 0); 456 const size_t prefix_len = SSL3_RT_HEADER_LENGTH; 457 458 /* Write the 1-byte fragment into |out_prefix|. */ 459 uint8_t *split_body = out_prefix + prefix_len; 460 uint8_t *split_suffix = split_body + 1; 461 462 /* TODO(martinkr): Make AEAD code not complain if max_suffix_len is lower 463 * than |EVP_AEAD_max_overhead| but still sufficiently large. */ 464 size_t split_max_suffix_len = 465 SSL_AEAD_CTX_max_suffix_len(ssl->s3->aead_write_ctx, 0); 466 size_t split_suffix_len = 0; 467 if (!do_seal_record(ssl, out_prefix, split_body, split_suffix, 468 &split_suffix_len, split_max_suffix_len, type, in, 1)) { 469 return 0; 470 } 471 472 size_t split_record_len = prefix_len + 1 + split_suffix_len; 473 474 assert(SSL3_RT_HEADER_LENGTH + ssl_cipher_get_record_split_len( 475 ssl->s3->aead_write_ctx->cipher) == 476 split_record_len); 477 478 /* Write the n-1-byte fragment. The header gets split between |out_prefix| 479 * (header[:-1]) and |out| (header[-1:]). */ 480 uint8_t tmp_prefix[SSL3_RT_HEADER_LENGTH]; 481 if (!do_seal_record(ssl, tmp_prefix, out + 1, out_suffix, out_suffix_len, 482 max_out_suffix_len, type, in + 1, in_len - 1)) { 483 return 0; 484 } 485 assert(tls_seal_scatter_prefix_len(ssl, type, in_len) == 486 split_record_len + SSL3_RT_HEADER_LENGTH - 1); 487 OPENSSL_memcpy(out_prefix + split_record_len, tmp_prefix, 488 SSL3_RT_HEADER_LENGTH - 1); 489 OPENSSL_memcpy(out, tmp_prefix + SSL3_RT_HEADER_LENGTH - 1, 1); 490 return 1; 491 } 492 493 return do_seal_record(ssl, out_prefix, out, out_suffix, out_suffix_len, 494 max_out_suffix_len, type, in, in_len); 495 } 496 497 int tls_seal_record(SSL *ssl, uint8_t *out, size_t *out_len, size_t max_out_len, 498 uint8_t type, const uint8_t *in, size_t in_len) { 499 if (buffers_alias(in, in_len, out, max_out_len)) { 500 OPENSSL_PUT_ERROR(SSL, SSL_R_OUTPUT_ALIASES_INPUT); 501 return 0; 502 } 503 504 const size_t prefix_len = tls_seal_scatter_prefix_len(ssl, type, in_len); 505 506 if (in_len + prefix_len < in_len) { 507 OPENSSL_PUT_ERROR(SSL, SSL_R_RECORD_TOO_LARGE); 508 return 0; 509 } 510 if (max_out_len < in_len + prefix_len) { 511 OPENSSL_PUT_ERROR(SSL, SSL_R_BUFFER_TOO_SMALL); 512 return 0; 513 } 514 515 uint8_t *prefix = out; 516 uint8_t *body = out + prefix_len; 517 uint8_t *suffix = body + in_len; 518 size_t max_suffix_len = max_out_len - prefix_len - in_len; 519 size_t suffix_len = 0; 520 521 if (!tls_seal_scatter_record(ssl, prefix, body, suffix, &suffix_len, 522 max_suffix_len, type, in, in_len)) { 523 return 0; 524 } 525 526 if (prefix_len + in_len + suffix_len < prefix_len + in_len) { 527 OPENSSL_PUT_ERROR(SSL, SSL_R_RECORD_TOO_LARGE); 528 return 0; 529 } 530 531 *out_len = prefix_len + in_len + suffix_len; 532 return 1; 533 } 534 535 enum ssl_open_record_t ssl_process_alert(SSL *ssl, uint8_t *out_alert, 536 const uint8_t *in, size_t in_len) { 537 /* Alerts records may not contain fragmented or multiple alerts. */ 538 if (in_len != 2) { 539 *out_alert = SSL_AD_DECODE_ERROR; 540 OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_ALERT); 541 return ssl_open_record_error; 542 } 543 544 ssl_do_msg_callback(ssl, 0 /* read */, SSL3_RT_ALERT, in, in_len); 545 546 const uint8_t alert_level = in[0]; 547 const uint8_t alert_descr = in[1]; 548 549 uint16_t alert = (alert_level << 8) | alert_descr; 550 ssl_do_info_callback(ssl, SSL_CB_READ_ALERT, alert); 551 552 if (alert_level == SSL3_AL_WARNING) { 553 if (alert_descr == SSL_AD_CLOSE_NOTIFY) { 554 ssl->s3->recv_shutdown = ssl_shutdown_close_notify; 555 return ssl_open_record_close_notify; 556 } 557 558 /* Warning alerts do not exist in TLS 1.3. */ 559 if (ssl->s3->have_version && 560 ssl3_protocol_version(ssl) >= TLS1_3_VERSION) { 561 *out_alert = SSL_AD_DECODE_ERROR; 562 OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_ALERT); 563 return ssl_open_record_error; 564 } 565 566 ssl->s3->warning_alert_count++; 567 if (ssl->s3->warning_alert_count > kMaxWarningAlerts) { 568 *out_alert = SSL_AD_UNEXPECTED_MESSAGE; 569 OPENSSL_PUT_ERROR(SSL, SSL_R_TOO_MANY_WARNING_ALERTS); 570 return ssl_open_record_error; 571 } 572 return ssl_open_record_discard; 573 } 574 575 if (alert_level == SSL3_AL_FATAL) { 576 ssl->s3->recv_shutdown = ssl_shutdown_fatal_alert; 577 578 char tmp[16]; 579 OPENSSL_PUT_ERROR(SSL, SSL_AD_REASON_OFFSET + alert_descr); 580 BIO_snprintf(tmp, sizeof(tmp), "%d", alert_descr); 581 ERR_add_error_data(2, "SSL alert number ", tmp); 582 return ssl_open_record_fatal_alert; 583 } 584 585 *out_alert = SSL_AD_ILLEGAL_PARAMETER; 586 OPENSSL_PUT_ERROR(SSL, SSL_R_UNKNOWN_ALERT_TYPE); 587 return ssl_open_record_error; 588 } 589
