1 /* 2 * Copyright 2016-2020 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 <string.h> 11 #include "internal/nelem.h" 12 #include "internal/cryptlib.h" 13 #include "../ssl_local.h" 14 #include "statem_local.h" 15 #include "internal/cryptlib.h" 16 17 static int final_renegotiate(SSL *s, unsigned int context, int sent); 18 static int init_server_name(SSL *s, unsigned int context); 19 static int final_server_name(SSL *s, unsigned int context, int sent); 20 #ifndef OPENSSL_NO_EC 21 static int final_ec_pt_formats(SSL *s, unsigned int context, int sent); 22 #endif 23 static int init_session_ticket(SSL *s, unsigned int context); 24 #ifndef OPENSSL_NO_OCSP 25 static int init_status_request(SSL *s, unsigned int context); 26 #endif 27 #ifndef OPENSSL_NO_NEXTPROTONEG 28 static int init_npn(SSL *s, unsigned int context); 29 #endif 30 static int init_alpn(SSL *s, unsigned int context); 31 static int final_alpn(SSL *s, unsigned int context, int sent); 32 static int init_sig_algs_cert(SSL *s, unsigned int context); 33 static int init_sig_algs(SSL *s, unsigned int context); 34 static int init_certificate_authorities(SSL *s, unsigned int context); 35 static EXT_RETURN tls_construct_certificate_authorities(SSL *s, WPACKET *pkt, 36 unsigned int context, 37 X509 *x, 38 size_t chainidx); 39 static int tls_parse_certificate_authorities(SSL *s, PACKET *pkt, 40 unsigned int context, X509 *x, 41 size_t chainidx); 42 #ifndef OPENSSL_NO_SRP 43 static int init_srp(SSL *s, unsigned int context); 44 #endif 45 static int init_etm(SSL *s, unsigned int context); 46 static int init_ems(SSL *s, unsigned int context); 47 static int final_ems(SSL *s, unsigned int context, int sent); 48 static int init_psk_kex_modes(SSL *s, unsigned int context); 49 #ifndef OPENSSL_NO_EC 50 static int final_key_share(SSL *s, unsigned int context, int sent); 51 #endif 52 #ifndef OPENSSL_NO_SRTP 53 static int init_srtp(SSL *s, unsigned int context); 54 #endif 55 static int final_sig_algs(SSL *s, unsigned int context, int sent); 56 static int final_early_data(SSL *s, unsigned int context, int sent); 57 static int final_maxfragmentlen(SSL *s, unsigned int context, int sent); 58 static int init_post_handshake_auth(SSL *s, unsigned int context); 59 60 /* Structure to define a built-in extension */ 61 typedef struct extensions_definition_st { 62 /* The defined type for the extension */ 63 unsigned int type; 64 /* 65 * The context that this extension applies to, e.g. what messages and 66 * protocol versions 67 */ 68 unsigned int context; 69 /* 70 * Initialise extension before parsing. Always called for relevant contexts 71 * even if extension not present 72 */ 73 int (*init)(SSL *s, unsigned int context); 74 /* Parse extension sent from client to server */ 75 int (*parse_ctos)(SSL *s, PACKET *pkt, unsigned int context, X509 *x, 76 size_t chainidx); 77 /* Parse extension send from server to client */ 78 int (*parse_stoc)(SSL *s, PACKET *pkt, unsigned int context, X509 *x, 79 size_t chainidx); 80 /* Construct extension sent from server to client */ 81 EXT_RETURN (*construct_stoc)(SSL *s, WPACKET *pkt, unsigned int context, 82 X509 *x, size_t chainidx); 83 /* Construct extension sent from client to server */ 84 EXT_RETURN (*construct_ctos)(SSL *s, WPACKET *pkt, unsigned int context, 85 X509 *x, size_t chainidx); 86 /* 87 * Finalise extension after parsing. Always called where an extensions was 88 * initialised even if the extension was not present. |sent| is set to 1 if 89 * the extension was seen, or 0 otherwise. 90 */ 91 int (*final)(SSL *s, unsigned int context, int sent); 92 } EXTENSION_DEFINITION; 93 94 /* 95 * Definitions of all built-in extensions. NOTE: Changes in the number or order 96 * of these extensions should be mirrored with equivalent changes to the 97 * indexes ( TLSEXT_IDX_* ) defined in ssl_local.h. 98 * Each extension has an initialiser, a client and 99 * server side parser and a finaliser. The initialiser is called (if the 100 * extension is relevant to the given context) even if we did not see the 101 * extension in the message that we received. The parser functions are only 102 * called if we see the extension in the message. The finalisers are always 103 * called if the initialiser was called. 104 * There are also server and client side constructor functions which are always 105 * called during message construction if the extension is relevant for the 106 * given context. 107 * The initialisation, parsing, finalisation and construction functions are 108 * always called in the order defined in this list. Some extensions may depend 109 * on others having been processed first, so the order of this list is 110 * significant. 111 * The extension context is defined by a series of flags which specify which 112 * messages the extension is relevant to. These flags also specify whether the 113 * extension is relevant to a particular protocol or protocol version. 114 * 115 * TODO(TLS1.3): Make sure we have a test to check the consistency of these 116 * 117 * NOTE: WebSphere Application Server 7+ cannot handle empty extensions at 118 * the end, keep these extensions before signature_algorithm. 119 */ 120 #define INVALID_EXTENSION { 0x10000, 0, NULL, NULL, NULL, NULL, NULL, NULL } 121 static const EXTENSION_DEFINITION ext_defs[] = { 122 { 123 TLSEXT_TYPE_renegotiate, 124 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO 125 | SSL_EXT_SSL3_ALLOWED | SSL_EXT_TLS1_2_AND_BELOW_ONLY, 126 NULL, tls_parse_ctos_renegotiate, tls_parse_stoc_renegotiate, 127 tls_construct_stoc_renegotiate, tls_construct_ctos_renegotiate, 128 final_renegotiate 129 }, 130 { 131 TLSEXT_TYPE_server_name, 132 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO 133 | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS, 134 init_server_name, 135 tls_parse_ctos_server_name, tls_parse_stoc_server_name, 136 tls_construct_stoc_server_name, tls_construct_ctos_server_name, 137 final_server_name 138 }, 139 { 140 TLSEXT_TYPE_max_fragment_length, 141 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO 142 | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS, 143 NULL, tls_parse_ctos_maxfragmentlen, tls_parse_stoc_maxfragmentlen, 144 tls_construct_stoc_maxfragmentlen, tls_construct_ctos_maxfragmentlen, 145 final_maxfragmentlen 146 }, 147 #ifndef OPENSSL_NO_SRP 148 { 149 TLSEXT_TYPE_srp, 150 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_AND_BELOW_ONLY, 151 init_srp, tls_parse_ctos_srp, NULL, NULL, tls_construct_ctos_srp, NULL 152 }, 153 #else 154 INVALID_EXTENSION, 155 #endif 156 #ifndef OPENSSL_NO_EC 157 { 158 TLSEXT_TYPE_ec_point_formats, 159 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO 160 | SSL_EXT_TLS1_2_AND_BELOW_ONLY, 161 NULL, tls_parse_ctos_ec_pt_formats, tls_parse_stoc_ec_pt_formats, 162 tls_construct_stoc_ec_pt_formats, tls_construct_ctos_ec_pt_formats, 163 final_ec_pt_formats 164 }, 165 { 166 /* 167 * "supported_groups" is spread across several specifications. 168 * It was originally specified as "elliptic_curves" in RFC 4492, 169 * and broadened to include named FFDH groups by RFC 7919. 170 * Both RFCs 4492 and 7919 do not include a provision for the server 171 * to indicate to the client the complete list of groups supported 172 * by the server, with the server instead just indicating the 173 * selected group for this connection in the ServerKeyExchange 174 * message. TLS 1.3 adds a scheme for the server to indicate 175 * to the client its list of supported groups in the 176 * EncryptedExtensions message, but none of the relevant 177 * specifications permit sending supported_groups in the ServerHello. 178 * Nonetheless (possibly due to the close proximity to the 179 * "ec_point_formats" extension, which is allowed in the ServerHello), 180 * there are several servers that send this extension in the 181 * ServerHello anyway. Up to and including the 1.1.0 release, 182 * we did not check for the presence of nonpermitted extensions, 183 * so to avoid a regression, we must permit this extension in the 184 * TLS 1.2 ServerHello as well. 185 * 186 * Note that there is no tls_parse_stoc_supported_groups function, 187 * so we do not perform any additional parsing, validation, or 188 * processing on the server's group list -- this is just a minimal 189 * change to preserve compatibility with these misbehaving servers. 190 */ 191 TLSEXT_TYPE_supported_groups, 192 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS 193 | SSL_EXT_TLS1_2_SERVER_HELLO, 194 NULL, tls_parse_ctos_supported_groups, NULL, 195 tls_construct_stoc_supported_groups, 196 tls_construct_ctos_supported_groups, NULL 197 }, 198 #else 199 INVALID_EXTENSION, 200 INVALID_EXTENSION, 201 #endif 202 { 203 TLSEXT_TYPE_session_ticket, 204 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO 205 | SSL_EXT_TLS1_2_AND_BELOW_ONLY, 206 init_session_ticket, tls_parse_ctos_session_ticket, 207 tls_parse_stoc_session_ticket, tls_construct_stoc_session_ticket, 208 tls_construct_ctos_session_ticket, NULL 209 }, 210 #ifndef OPENSSL_NO_OCSP 211 { 212 TLSEXT_TYPE_status_request, 213 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO 214 | SSL_EXT_TLS1_3_CERTIFICATE | SSL_EXT_TLS1_3_CERTIFICATE_REQUEST, 215 init_status_request, tls_parse_ctos_status_request, 216 tls_parse_stoc_status_request, tls_construct_stoc_status_request, 217 tls_construct_ctos_status_request, NULL 218 }, 219 #else 220 INVALID_EXTENSION, 221 #endif 222 #ifndef OPENSSL_NO_NEXTPROTONEG 223 { 224 TLSEXT_TYPE_next_proto_neg, 225 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO 226 | SSL_EXT_TLS1_2_AND_BELOW_ONLY, 227 init_npn, tls_parse_ctos_npn, tls_parse_stoc_npn, 228 tls_construct_stoc_next_proto_neg, tls_construct_ctos_npn, NULL 229 }, 230 #else 231 INVALID_EXTENSION, 232 #endif 233 { 234 /* 235 * Must appear in this list after server_name so that finalisation 236 * happens after server_name callbacks 237 */ 238 TLSEXT_TYPE_application_layer_protocol_negotiation, 239 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO 240 | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS, 241 init_alpn, tls_parse_ctos_alpn, tls_parse_stoc_alpn, 242 tls_construct_stoc_alpn, tls_construct_ctos_alpn, final_alpn 243 }, 244 #ifndef OPENSSL_NO_SRTP 245 { 246 TLSEXT_TYPE_use_srtp, 247 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO 248 | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS | SSL_EXT_DTLS_ONLY, 249 init_srtp, tls_parse_ctos_use_srtp, tls_parse_stoc_use_srtp, 250 tls_construct_stoc_use_srtp, tls_construct_ctos_use_srtp, NULL 251 }, 252 #else 253 INVALID_EXTENSION, 254 #endif 255 { 256 TLSEXT_TYPE_encrypt_then_mac, 257 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO 258 | SSL_EXT_TLS1_2_AND_BELOW_ONLY, 259 init_etm, tls_parse_ctos_etm, tls_parse_stoc_etm, 260 tls_construct_stoc_etm, tls_construct_ctos_etm, NULL 261 }, 262 #ifndef OPENSSL_NO_CT 263 { 264 TLSEXT_TYPE_signed_certificate_timestamp, 265 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO 266 | SSL_EXT_TLS1_3_CERTIFICATE | SSL_EXT_TLS1_3_CERTIFICATE_REQUEST, 267 NULL, 268 /* 269 * No server side support for this, but can be provided by a custom 270 * extension. This is an exception to the rule that custom extensions 271 * cannot override built in ones. 272 */ 273 NULL, tls_parse_stoc_sct, NULL, tls_construct_ctos_sct, NULL 274 }, 275 #else 276 INVALID_EXTENSION, 277 #endif 278 { 279 TLSEXT_TYPE_extended_master_secret, 280 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO 281 | SSL_EXT_TLS1_2_AND_BELOW_ONLY, 282 init_ems, tls_parse_ctos_ems, tls_parse_stoc_ems, 283 tls_construct_stoc_ems, tls_construct_ctos_ems, final_ems 284 }, 285 { 286 TLSEXT_TYPE_signature_algorithms_cert, 287 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_CERTIFICATE_REQUEST, 288 init_sig_algs_cert, tls_parse_ctos_sig_algs_cert, 289 tls_parse_ctos_sig_algs_cert, 290 /* We do not generate signature_algorithms_cert at present. */ 291 NULL, NULL, NULL 292 }, 293 { 294 TLSEXT_TYPE_post_handshake_auth, 295 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_ONLY, 296 init_post_handshake_auth, 297 tls_parse_ctos_post_handshake_auth, NULL, 298 NULL, tls_construct_ctos_post_handshake_auth, 299 NULL, 300 }, 301 { 302 TLSEXT_TYPE_signature_algorithms, 303 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_CERTIFICATE_REQUEST, 304 init_sig_algs, tls_parse_ctos_sig_algs, 305 tls_parse_ctos_sig_algs, tls_construct_ctos_sig_algs, 306 tls_construct_ctos_sig_algs, final_sig_algs 307 }, 308 { 309 TLSEXT_TYPE_supported_versions, 310 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_SERVER_HELLO 311 | SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST | SSL_EXT_TLS_IMPLEMENTATION_ONLY, 312 NULL, 313 /* Processed inline as part of version selection */ 314 NULL, tls_parse_stoc_supported_versions, 315 tls_construct_stoc_supported_versions, 316 tls_construct_ctos_supported_versions, NULL 317 }, 318 { 319 TLSEXT_TYPE_psk_kex_modes, 320 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS_IMPLEMENTATION_ONLY 321 | SSL_EXT_TLS1_3_ONLY, 322 init_psk_kex_modes, tls_parse_ctos_psk_kex_modes, NULL, NULL, 323 tls_construct_ctos_psk_kex_modes, NULL 324 }, 325 #ifndef OPENSSL_NO_EC 326 { 327 /* 328 * Must be in this list after supported_groups. We need that to have 329 * been parsed before we do this one. 330 */ 331 TLSEXT_TYPE_key_share, 332 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_SERVER_HELLO 333 | SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST | SSL_EXT_TLS_IMPLEMENTATION_ONLY 334 | SSL_EXT_TLS1_3_ONLY, 335 NULL, tls_parse_ctos_key_share, tls_parse_stoc_key_share, 336 tls_construct_stoc_key_share, tls_construct_ctos_key_share, 337 final_key_share 338 }, 339 #endif 340 { 341 /* Must be after key_share */ 342 TLSEXT_TYPE_cookie, 343 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST 344 | SSL_EXT_TLS_IMPLEMENTATION_ONLY | SSL_EXT_TLS1_3_ONLY, 345 NULL, tls_parse_ctos_cookie, tls_parse_stoc_cookie, 346 tls_construct_stoc_cookie, tls_construct_ctos_cookie, NULL 347 }, 348 { 349 /* 350 * Special unsolicited ServerHello extension only used when 351 * SSL_OP_CRYPTOPRO_TLSEXT_BUG is set. We allow it in a ClientHello but 352 * ignore it. 353 */ 354 TLSEXT_TYPE_cryptopro_bug, 355 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO 356 | SSL_EXT_TLS1_2_AND_BELOW_ONLY, 357 NULL, NULL, NULL, tls_construct_stoc_cryptopro_bug, NULL, NULL 358 }, 359 { 360 TLSEXT_TYPE_early_data, 361 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS 362 | SSL_EXT_TLS1_3_NEW_SESSION_TICKET | SSL_EXT_TLS1_3_ONLY, 363 NULL, tls_parse_ctos_early_data, tls_parse_stoc_early_data, 364 tls_construct_stoc_early_data, tls_construct_ctos_early_data, 365 final_early_data 366 }, 367 { 368 TLSEXT_TYPE_certificate_authorities, 369 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_CERTIFICATE_REQUEST 370 | SSL_EXT_TLS1_3_ONLY, 371 init_certificate_authorities, 372 tls_parse_certificate_authorities, tls_parse_certificate_authorities, 373 tls_construct_certificate_authorities, 374 tls_construct_certificate_authorities, NULL, 375 }, 376 { 377 /* Must be immediately before pre_shared_key */ 378 TLSEXT_TYPE_padding, 379 SSL_EXT_CLIENT_HELLO, 380 NULL, 381 /* We send this, but don't read it */ 382 NULL, NULL, NULL, tls_construct_ctos_padding, NULL 383 }, 384 { 385 /* Required by the TLSv1.3 spec to always be the last extension */ 386 TLSEXT_TYPE_psk, 387 SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_3_SERVER_HELLO 388 | SSL_EXT_TLS_IMPLEMENTATION_ONLY | SSL_EXT_TLS1_3_ONLY, 389 NULL, tls_parse_ctos_psk, tls_parse_stoc_psk, tls_construct_stoc_psk, 390 tls_construct_ctos_psk, NULL 391 } 392 }; 393 394 /* Check whether an extension's context matches the current context */ 395 static int validate_context(SSL *s, unsigned int extctx, unsigned int thisctx) 396 { 397 /* Check we're allowed to use this extension in this context */ 398 if ((thisctx & extctx) == 0) 399 return 0; 400 401 if (SSL_IS_DTLS(s)) { 402 if ((extctx & SSL_EXT_TLS_ONLY) != 0) 403 return 0; 404 } else if ((extctx & SSL_EXT_DTLS_ONLY) != 0) { 405 return 0; 406 } 407 408 return 1; 409 } 410 411 int tls_validate_all_contexts(SSL *s, unsigned int thisctx, RAW_EXTENSION *exts) 412 { 413 size_t i, num_exts, builtin_num = OSSL_NELEM(ext_defs), offset; 414 RAW_EXTENSION *thisext; 415 unsigned int context; 416 ENDPOINT role = ENDPOINT_BOTH; 417 418 if ((thisctx & SSL_EXT_CLIENT_HELLO) != 0) 419 role = ENDPOINT_SERVER; 420 else if ((thisctx & SSL_EXT_TLS1_2_SERVER_HELLO) != 0) 421 role = ENDPOINT_CLIENT; 422 423 /* Calculate the number of extensions in the extensions list */ 424 num_exts = builtin_num + s->cert->custext.meths_count; 425 426 for (thisext = exts, i = 0; i < num_exts; i++, thisext++) { 427 if (!thisext->present) 428 continue; 429 430 if (i < builtin_num) { 431 context = ext_defs[i].context; 432 } else { 433 custom_ext_method *meth = NULL; 434 435 meth = custom_ext_find(&s->cert->custext, role, thisext->type, 436 &offset); 437 if (!ossl_assert(meth != NULL)) 438 return 0; 439 context = meth->context; 440 } 441 442 if (!validate_context(s, context, thisctx)) 443 return 0; 444 } 445 446 return 1; 447 } 448 449 /* 450 * Verify whether we are allowed to use the extension |type| in the current 451 * |context|. Returns 1 to indicate the extension is allowed or unknown or 0 to 452 * indicate the extension is not allowed. If returning 1 then |*found| is set to 453 * the definition for the extension we found. 454 */ 455 static int verify_extension(SSL *s, unsigned int context, unsigned int type, 456 custom_ext_methods *meths, RAW_EXTENSION *rawexlist, 457 RAW_EXTENSION **found) 458 { 459 size_t i; 460 size_t builtin_num = OSSL_NELEM(ext_defs); 461 const EXTENSION_DEFINITION *thisext; 462 463 for (i = 0, thisext = ext_defs; i < builtin_num; i++, thisext++) { 464 if (type == thisext->type) { 465 if (!validate_context(s, thisext->context, context)) 466 return 0; 467 468 *found = &rawexlist[i]; 469 return 1; 470 } 471 } 472 473 /* Check the custom extensions */ 474 if (meths != NULL) { 475 size_t offset = 0; 476 ENDPOINT role = ENDPOINT_BOTH; 477 custom_ext_method *meth = NULL; 478 479 if ((context & SSL_EXT_CLIENT_HELLO) != 0) 480 role = ENDPOINT_SERVER; 481 else if ((context & SSL_EXT_TLS1_2_SERVER_HELLO) != 0) 482 role = ENDPOINT_CLIENT; 483 484 meth = custom_ext_find(meths, role, type, &offset); 485 if (meth != NULL) { 486 if (!validate_context(s, meth->context, context)) 487 return 0; 488 *found = &rawexlist[offset + builtin_num]; 489 return 1; 490 } 491 } 492 493 /* Unknown extension. We allow it */ 494 *found = NULL; 495 return 1; 496 } 497 498 /* 499 * Check whether the context defined for an extension |extctx| means whether 500 * the extension is relevant for the current context |thisctx| or not. Returns 501 * 1 if the extension is relevant for this context, and 0 otherwise 502 */ 503 int extension_is_relevant(SSL *s, unsigned int extctx, unsigned int thisctx) 504 { 505 int is_tls13; 506 507 /* 508 * For HRR we haven't selected the version yet but we know it will be 509 * TLSv1.3 510 */ 511 if ((thisctx & SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST) != 0) 512 is_tls13 = 1; 513 else 514 is_tls13 = SSL_IS_TLS13(s); 515 516 if ((SSL_IS_DTLS(s) 517 && (extctx & SSL_EXT_TLS_IMPLEMENTATION_ONLY) != 0) 518 || (s->version == SSL3_VERSION 519 && (extctx & SSL_EXT_SSL3_ALLOWED) == 0) 520 /* 521 * Note that SSL_IS_TLS13() means "TLS 1.3 has been negotiated", 522 * which is never true when generating the ClientHello. 523 * However, version negotiation *has* occurred by the time the 524 * ClientHello extensions are being parsed. 525 * Be careful to allow TLS 1.3-only extensions when generating 526 * the ClientHello. 527 */ 528 || (is_tls13 && (extctx & SSL_EXT_TLS1_2_AND_BELOW_ONLY) != 0) 529 || (!is_tls13 && (extctx & SSL_EXT_TLS1_3_ONLY) != 0 530 && (thisctx & SSL_EXT_CLIENT_HELLO) == 0) 531 || (s->server && !is_tls13 && (extctx & SSL_EXT_TLS1_3_ONLY) != 0) 532 || (s->hit && (extctx & SSL_EXT_IGNORE_ON_RESUMPTION) != 0)) 533 return 0; 534 return 1; 535 } 536 537 /* 538 * Gather a list of all the extensions from the data in |packet]. |context| 539 * tells us which message this extension is for. The raw extension data is 540 * stored in |*res| on success. We don't actually process the content of the 541 * extensions yet, except to check their types. This function also runs the 542 * initialiser functions for all known extensions if |init| is nonzero (whether 543 * we have collected them or not). If successful the caller is responsible for 544 * freeing the contents of |*res|. 545 * 546 * Per http://tools.ietf.org/html/rfc5246#section-7.4.1.4, there may not be 547 * more than one extension of the same type in a ClientHello or ServerHello. 548 * This function returns 1 if all extensions are unique and we have parsed their 549 * types, and 0 if the extensions contain duplicates, could not be successfully 550 * found, or an internal error occurred. We only check duplicates for 551 * extensions that we know about. We ignore others. 552 */ 553 int tls_collect_extensions(SSL *s, PACKET *packet, unsigned int context, 554 RAW_EXTENSION **res, size_t *len, int init) 555 { 556 PACKET extensions = *packet; 557 size_t i = 0; 558 size_t num_exts; 559 custom_ext_methods *exts = &s->cert->custext; 560 RAW_EXTENSION *raw_extensions = NULL; 561 const EXTENSION_DEFINITION *thisexd; 562 563 *res = NULL; 564 565 /* 566 * Initialise server side custom extensions. Client side is done during 567 * construction of extensions for the ClientHello. 568 */ 569 if ((context & SSL_EXT_CLIENT_HELLO) != 0) 570 custom_ext_init(&s->cert->custext); 571 572 num_exts = OSSL_NELEM(ext_defs) + (exts != NULL ? exts->meths_count : 0); 573 raw_extensions = OPENSSL_zalloc(num_exts * sizeof(*raw_extensions)); 574 if (raw_extensions == NULL) { 575 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_COLLECT_EXTENSIONS, 576 ERR_R_MALLOC_FAILURE); 577 return 0; 578 } 579 580 i = 0; 581 while (PACKET_remaining(&extensions) > 0) { 582 unsigned int type, idx; 583 PACKET extension; 584 RAW_EXTENSION *thisex; 585 586 if (!PACKET_get_net_2(&extensions, &type) || 587 !PACKET_get_length_prefixed_2(&extensions, &extension)) { 588 SSLfatal(s, SSL_AD_DECODE_ERROR, SSL_F_TLS_COLLECT_EXTENSIONS, 589 SSL_R_BAD_EXTENSION); 590 goto err; 591 } 592 /* 593 * Verify this extension is allowed. We only check duplicates for 594 * extensions that we recognise. We also have a special case for the 595 * PSK extension, which must be the last one in the ClientHello. 596 */ 597 if (!verify_extension(s, context, type, exts, raw_extensions, &thisex) 598 || (thisex != NULL && thisex->present == 1) 599 || (type == TLSEXT_TYPE_psk 600 && (context & SSL_EXT_CLIENT_HELLO) != 0 601 && PACKET_remaining(&extensions) != 0)) { 602 SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_COLLECT_EXTENSIONS, 603 SSL_R_BAD_EXTENSION); 604 goto err; 605 } 606 idx = thisex - raw_extensions; 607 /*- 608 * Check that we requested this extension (if appropriate). Requests can 609 * be sent in the ClientHello and CertificateRequest. Unsolicited 610 * extensions can be sent in the NewSessionTicket. We only do this for 611 * the built-in extensions. Custom extensions have a different but 612 * similar check elsewhere. 613 * Special cases: 614 * - The HRR cookie extension is unsolicited 615 * - The renegotiate extension is unsolicited (the client signals 616 * support via an SCSV) 617 * - The signed_certificate_timestamp extension can be provided by a 618 * custom extension or by the built-in version. We let the extension 619 * itself handle unsolicited response checks. 620 */ 621 if (idx < OSSL_NELEM(ext_defs) 622 && (context & (SSL_EXT_CLIENT_HELLO 623 | SSL_EXT_TLS1_3_CERTIFICATE_REQUEST 624 | SSL_EXT_TLS1_3_NEW_SESSION_TICKET)) == 0 625 && type != TLSEXT_TYPE_cookie 626 && type != TLSEXT_TYPE_renegotiate 627 && type != TLSEXT_TYPE_signed_certificate_timestamp 628 && (s->ext.extflags[idx] & SSL_EXT_FLAG_SENT) == 0 629 #ifndef OPENSSL_NO_GOST 630 && !((context & SSL_EXT_TLS1_2_SERVER_HELLO) != 0 631 && type == TLSEXT_TYPE_cryptopro_bug) 632 #endif 633 ) { 634 SSLfatal(s, SSL_AD_UNSUPPORTED_EXTENSION, 635 SSL_F_TLS_COLLECT_EXTENSIONS, SSL_R_UNSOLICITED_EXTENSION); 636 goto err; 637 } 638 if (thisex != NULL) { 639 thisex->data = extension; 640 thisex->present = 1; 641 thisex->type = type; 642 thisex->received_order = i++; 643 if (s->ext.debug_cb) 644 s->ext.debug_cb(s, !s->server, thisex->type, 645 PACKET_data(&thisex->data), 646 PACKET_remaining(&thisex->data), 647 s->ext.debug_arg); 648 } 649 } 650 651 if (init) { 652 /* 653 * Initialise all known extensions relevant to this context, 654 * whether we have found them or not 655 */ 656 for (thisexd = ext_defs, i = 0; i < OSSL_NELEM(ext_defs); 657 i++, thisexd++) { 658 if (thisexd->init != NULL && (thisexd->context & context) != 0 659 && extension_is_relevant(s, thisexd->context, context) 660 && !thisexd->init(s, context)) { 661 /* SSLfatal() already called */ 662 goto err; 663 } 664 } 665 } 666 667 *res = raw_extensions; 668 if (len != NULL) 669 *len = num_exts; 670 return 1; 671 672 err: 673 OPENSSL_free(raw_extensions); 674 return 0; 675 } 676 677 /* 678 * Runs the parser for a given extension with index |idx|. |exts| contains the 679 * list of all parsed extensions previously collected by 680 * tls_collect_extensions(). The parser is only run if it is applicable for the 681 * given |context| and the parser has not already been run. If this is for a 682 * Certificate message, then we also provide the parser with the relevant 683 * Certificate |x| and its position in the |chainidx| with 0 being the first 684 * Certificate. Returns 1 on success or 0 on failure. If an extension is not 685 * present this counted as success. 686 */ 687 int tls_parse_extension(SSL *s, TLSEXT_INDEX idx, int context, 688 RAW_EXTENSION *exts, X509 *x, size_t chainidx) 689 { 690 RAW_EXTENSION *currext = &exts[idx]; 691 int (*parser)(SSL *s, PACKET *pkt, unsigned int context, X509 *x, 692 size_t chainidx) = NULL; 693 694 /* Skip if the extension is not present */ 695 if (!currext->present) 696 return 1; 697 698 /* Skip if we've already parsed this extension */ 699 if (currext->parsed) 700 return 1; 701 702 currext->parsed = 1; 703 704 if (idx < OSSL_NELEM(ext_defs)) { 705 /* We are handling a built-in extension */ 706 const EXTENSION_DEFINITION *extdef = &ext_defs[idx]; 707 708 /* Check if extension is defined for our protocol. If not, skip */ 709 if (!extension_is_relevant(s, extdef->context, context)) 710 return 1; 711 712 parser = s->server ? extdef->parse_ctos : extdef->parse_stoc; 713 714 if (parser != NULL) 715 return parser(s, &currext->data, context, x, chainidx); 716 717 /* 718 * If the parser is NULL we fall through to the custom extension 719 * processing 720 */ 721 } 722 723 /* Parse custom extensions */ 724 return custom_ext_parse(s, context, currext->type, 725 PACKET_data(&currext->data), 726 PACKET_remaining(&currext->data), 727 x, chainidx); 728 } 729 730 /* 731 * Parse all remaining extensions that have not yet been parsed. Also calls the 732 * finalisation for all extensions at the end if |fin| is nonzero, whether we 733 * collected them or not. Returns 1 for success or 0 for failure. If we are 734 * working on a Certificate message then we also pass the Certificate |x| and 735 * its position in the |chainidx|, with 0 being the first certificate. 736 */ 737 int tls_parse_all_extensions(SSL *s, int context, RAW_EXTENSION *exts, X509 *x, 738 size_t chainidx, int fin) 739 { 740 size_t i, numexts = OSSL_NELEM(ext_defs); 741 const EXTENSION_DEFINITION *thisexd; 742 743 /* Calculate the number of extensions in the extensions list */ 744 numexts += s->cert->custext.meths_count; 745 746 /* Parse each extension in turn */ 747 for (i = 0; i < numexts; i++) { 748 if (!tls_parse_extension(s, i, context, exts, x, chainidx)) { 749 /* SSLfatal() already called */ 750 return 0; 751 } 752 } 753 754 if (fin) { 755 /* 756 * Finalise all known extensions relevant to this context, 757 * whether we have found them or not 758 */ 759 for (i = 0, thisexd = ext_defs; i < OSSL_NELEM(ext_defs); 760 i++, thisexd++) { 761 if (thisexd->final != NULL && (thisexd->context & context) != 0 762 && !thisexd->final(s, context, exts[i].present)) { 763 /* SSLfatal() already called */ 764 return 0; 765 } 766 } 767 } 768 769 return 1; 770 } 771 772 int should_add_extension(SSL *s, unsigned int extctx, unsigned int thisctx, 773 int max_version) 774 { 775 /* Skip if not relevant for our context */ 776 if ((extctx & thisctx) == 0) 777 return 0; 778 779 /* Check if this extension is defined for our protocol. If not, skip */ 780 if (!extension_is_relevant(s, extctx, thisctx) 781 || ((extctx & SSL_EXT_TLS1_3_ONLY) != 0 782 && (thisctx & SSL_EXT_CLIENT_HELLO) != 0 783 && (SSL_IS_DTLS(s) || max_version < TLS1_3_VERSION))) 784 return 0; 785 786 return 1; 787 } 788 789 /* 790 * Construct all the extensions relevant to the current |context| and write 791 * them to |pkt|. If this is an extension for a Certificate in a Certificate 792 * message, then |x| will be set to the Certificate we are handling, and 793 * |chainidx| will indicate the position in the chainidx we are processing (with 794 * 0 being the first in the chain). Returns 1 on success or 0 on failure. On a 795 * failure construction stops at the first extension to fail to construct. 796 */ 797 int tls_construct_extensions(SSL *s, WPACKET *pkt, unsigned int context, 798 X509 *x, size_t chainidx) 799 { 800 size_t i; 801 int min_version, max_version = 0, reason; 802 const EXTENSION_DEFINITION *thisexd; 803 804 if (!WPACKET_start_sub_packet_u16(pkt) 805 /* 806 * If extensions are of zero length then we don't even add the 807 * extensions length bytes to a ClientHello/ServerHello 808 * (for non-TLSv1.3). 809 */ 810 || ((context & 811 (SSL_EXT_CLIENT_HELLO | SSL_EXT_TLS1_2_SERVER_HELLO)) != 0 812 && !WPACKET_set_flags(pkt, 813 WPACKET_FLAGS_ABANDON_ON_ZERO_LENGTH))) { 814 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_EXTENSIONS, 815 ERR_R_INTERNAL_ERROR); 816 return 0; 817 } 818 819 if ((context & SSL_EXT_CLIENT_HELLO) != 0) { 820 reason = ssl_get_min_max_version(s, &min_version, &max_version, NULL); 821 if (reason != 0) { 822 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_EXTENSIONS, 823 reason); 824 return 0; 825 } 826 } 827 828 /* Add custom extensions first */ 829 if ((context & SSL_EXT_CLIENT_HELLO) != 0) { 830 /* On the server side with initialise during ClientHello parsing */ 831 custom_ext_init(&s->cert->custext); 832 } 833 if (!custom_ext_add(s, context, pkt, x, chainidx, max_version)) { 834 /* SSLfatal() already called */ 835 return 0; 836 } 837 838 for (i = 0, thisexd = ext_defs; i < OSSL_NELEM(ext_defs); i++, thisexd++) { 839 EXT_RETURN (*construct)(SSL *s, WPACKET *pkt, unsigned int context, 840 X509 *x, size_t chainidx); 841 EXT_RETURN ret; 842 843 /* Skip if not relevant for our context */ 844 if (!should_add_extension(s, thisexd->context, context, max_version)) 845 continue; 846 847 construct = s->server ? thisexd->construct_stoc 848 : thisexd->construct_ctos; 849 850 if (construct == NULL) 851 continue; 852 853 ret = construct(s, pkt, context, x, chainidx); 854 if (ret == EXT_RETURN_FAIL) { 855 /* SSLfatal() already called */ 856 return 0; 857 } 858 if (ret == EXT_RETURN_SENT 859 && (context & (SSL_EXT_CLIENT_HELLO 860 | SSL_EXT_TLS1_3_CERTIFICATE_REQUEST 861 | SSL_EXT_TLS1_3_NEW_SESSION_TICKET)) != 0) 862 s->ext.extflags[i] |= SSL_EXT_FLAG_SENT; 863 } 864 865 if (!WPACKET_close(pkt)) { 866 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_CONSTRUCT_EXTENSIONS, 867 ERR_R_INTERNAL_ERROR); 868 return 0; 869 } 870 871 return 1; 872 } 873 874 /* 875 * Built in extension finalisation and initialisation functions. All initialise 876 * or finalise the associated extension type for the given |context|. For 877 * finalisers |sent| is set to 1 if we saw the extension during parsing, and 0 878 * otherwise. These functions return 1 on success or 0 on failure. 879 */ 880 881 static int final_renegotiate(SSL *s, unsigned int context, int sent) 882 { 883 if (!s->server) { 884 /* 885 * Check if we can connect to a server that doesn't support safe 886 * renegotiation 887 */ 888 if (!(s->options & SSL_OP_LEGACY_SERVER_CONNECT) 889 && !(s->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION) 890 && !sent) { 891 SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_F_FINAL_RENEGOTIATE, 892 SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED); 893 return 0; 894 } 895 896 return 1; 897 } 898 899 /* Need RI if renegotiating */ 900 if (s->renegotiate 901 && !(s->options & SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION) 902 && !sent) { 903 SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_F_FINAL_RENEGOTIATE, 904 SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED); 905 return 0; 906 } 907 908 909 return 1; 910 } 911 912 static int init_server_name(SSL *s, unsigned int context) 913 { 914 if (s->server) { 915 s->servername_done = 0; 916 917 OPENSSL_free(s->ext.hostname); 918 s->ext.hostname = NULL; 919 } 920 921 return 1; 922 } 923 924 static int final_server_name(SSL *s, unsigned int context, int sent) 925 { 926 int ret = SSL_TLSEXT_ERR_NOACK; 927 int altmp = SSL_AD_UNRECOGNIZED_NAME; 928 int was_ticket = (SSL_get_options(s) & SSL_OP_NO_TICKET) == 0; 929 930 if (!ossl_assert(s->ctx != NULL) || !ossl_assert(s->session_ctx != NULL)) { 931 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_FINAL_SERVER_NAME, 932 ERR_R_INTERNAL_ERROR); 933 return 0; 934 } 935 936 if (s->ctx->ext.servername_cb != NULL) 937 ret = s->ctx->ext.servername_cb(s, &altmp, 938 s->ctx->ext.servername_arg); 939 else if (s->session_ctx->ext.servername_cb != NULL) 940 ret = s->session_ctx->ext.servername_cb(s, &altmp, 941 s->session_ctx->ext.servername_arg); 942 943 /* 944 * For servers, propagate the SNI hostname from the temporary 945 * storage in the SSL to the persistent SSL_SESSION, now that we 946 * know we accepted it. 947 * Clients make this copy when parsing the server's response to 948 * the extension, which is when they find out that the negotiation 949 * was successful. 950 */ 951 if (s->server) { 952 if (sent && ret == SSL_TLSEXT_ERR_OK && !s->hit) { 953 /* Only store the hostname in the session if we accepted it. */ 954 OPENSSL_free(s->session->ext.hostname); 955 s->session->ext.hostname = OPENSSL_strdup(s->ext.hostname); 956 if (s->session->ext.hostname == NULL && s->ext.hostname != NULL) { 957 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_FINAL_SERVER_NAME, 958 ERR_R_INTERNAL_ERROR); 959 } 960 } 961 } 962 963 /* 964 * If we switched contexts (whether here or in the client_hello callback), 965 * move the sess_accept increment from the session_ctx to the new 966 * context, to avoid the confusing situation of having sess_accept_good 967 * exceed sess_accept (zero) for the new context. 968 */ 969 if (SSL_IS_FIRST_HANDSHAKE(s) && s->ctx != s->session_ctx) { 970 tsan_counter(&s->ctx->stats.sess_accept); 971 tsan_decr(&s->session_ctx->stats.sess_accept); 972 } 973 974 /* 975 * If we're expecting to send a ticket, and tickets were previously enabled, 976 * and now tickets are disabled, then turn off expected ticket. 977 * Also, if this is not a resumption, create a new session ID 978 */ 979 if (ret == SSL_TLSEXT_ERR_OK && s->ext.ticket_expected 980 && was_ticket && (SSL_get_options(s) & SSL_OP_NO_TICKET) != 0) { 981 s->ext.ticket_expected = 0; 982 if (!s->hit) { 983 SSL_SESSION* ss = SSL_get_session(s); 984 985 if (ss != NULL) { 986 OPENSSL_free(ss->ext.tick); 987 ss->ext.tick = NULL; 988 ss->ext.ticklen = 0; 989 ss->ext.tick_lifetime_hint = 0; 990 ss->ext.tick_age_add = 0; 991 if (!ssl_generate_session_id(s, ss)) { 992 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_FINAL_SERVER_NAME, 993 ERR_R_INTERNAL_ERROR); 994 return 0; 995 } 996 } else { 997 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_FINAL_SERVER_NAME, 998 ERR_R_INTERNAL_ERROR); 999 return 0; 1000 } 1001 } 1002 } 1003 1004 switch (ret) { 1005 case SSL_TLSEXT_ERR_ALERT_FATAL: 1006 SSLfatal(s, altmp, SSL_F_FINAL_SERVER_NAME, SSL_R_CALLBACK_FAILED); 1007 return 0; 1008 1009 case SSL_TLSEXT_ERR_ALERT_WARNING: 1010 /* TLSv1.3 doesn't have warning alerts so we suppress this */ 1011 if (!SSL_IS_TLS13(s)) 1012 ssl3_send_alert(s, SSL3_AL_WARNING, altmp); 1013 s->servername_done = 0; 1014 return 1; 1015 1016 case SSL_TLSEXT_ERR_NOACK: 1017 s->servername_done = 0; 1018 return 1; 1019 1020 default: 1021 return 1; 1022 } 1023 } 1024 1025 #ifndef OPENSSL_NO_EC 1026 static int final_ec_pt_formats(SSL *s, unsigned int context, int sent) 1027 { 1028 unsigned long alg_k, alg_a; 1029 1030 if (s->server) 1031 return 1; 1032 1033 alg_k = s->s3->tmp.new_cipher->algorithm_mkey; 1034 alg_a = s->s3->tmp.new_cipher->algorithm_auth; 1035 1036 /* 1037 * If we are client and using an elliptic curve cryptography cipher 1038 * suite, then if server returns an EC point formats lists extension it 1039 * must contain uncompressed. 1040 */ 1041 if (s->ext.ecpointformats != NULL 1042 && s->ext.ecpointformats_len > 0 1043 && s->ext.peer_ecpointformats != NULL 1044 && s->ext.peer_ecpointformats_len > 0 1045 && ((alg_k & SSL_kECDHE) || (alg_a & SSL_aECDSA))) { 1046 /* we are using an ECC cipher */ 1047 size_t i; 1048 unsigned char *list = s->ext.peer_ecpointformats; 1049 1050 for (i = 0; i < s->ext.peer_ecpointformats_len; i++) { 1051 if (*list++ == TLSEXT_ECPOINTFORMAT_uncompressed) 1052 break; 1053 } 1054 if (i == s->ext.peer_ecpointformats_len) { 1055 SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_FINAL_EC_PT_FORMATS, 1056 SSL_R_TLS_INVALID_ECPOINTFORMAT_LIST); 1057 return 0; 1058 } 1059 } 1060 1061 return 1; 1062 } 1063 #endif 1064 1065 static int init_session_ticket(SSL *s, unsigned int context) 1066 { 1067 if (!s->server) 1068 s->ext.ticket_expected = 0; 1069 1070 return 1; 1071 } 1072 1073 #ifndef OPENSSL_NO_OCSP 1074 static int init_status_request(SSL *s, unsigned int context) 1075 { 1076 if (s->server) { 1077 s->ext.status_type = TLSEXT_STATUSTYPE_nothing; 1078 } else { 1079 /* 1080 * Ensure we get sensible values passed to tlsext_status_cb in the event 1081 * that we don't receive a status message 1082 */ 1083 OPENSSL_free(s->ext.ocsp.resp); 1084 s->ext.ocsp.resp = NULL; 1085 s->ext.ocsp.resp_len = 0; 1086 } 1087 1088 return 1; 1089 } 1090 #endif 1091 1092 #ifndef OPENSSL_NO_NEXTPROTONEG 1093 static int init_npn(SSL *s, unsigned int context) 1094 { 1095 s->s3->npn_seen = 0; 1096 1097 return 1; 1098 } 1099 #endif 1100 1101 static int init_alpn(SSL *s, unsigned int context) 1102 { 1103 OPENSSL_free(s->s3->alpn_selected); 1104 s->s3->alpn_selected = NULL; 1105 s->s3->alpn_selected_len = 0; 1106 if (s->server) { 1107 OPENSSL_free(s->s3->alpn_proposed); 1108 s->s3->alpn_proposed = NULL; 1109 s->s3->alpn_proposed_len = 0; 1110 } 1111 return 1; 1112 } 1113 1114 static int final_alpn(SSL *s, unsigned int context, int sent) 1115 { 1116 if (!s->server && !sent && s->session->ext.alpn_selected != NULL) 1117 s->ext.early_data_ok = 0; 1118 1119 if (!s->server || !SSL_IS_TLS13(s)) 1120 return 1; 1121 1122 /* 1123 * Call alpn_select callback if needed. Has to be done after SNI and 1124 * cipher negotiation (HTTP/2 restricts permitted ciphers). In TLSv1.3 1125 * we also have to do this before we decide whether to accept early_data. 1126 * In TLSv1.3 we've already negotiated our cipher so we do this call now. 1127 * For < TLSv1.3 we defer it until after cipher negotiation. 1128 * 1129 * On failure SSLfatal() already called. 1130 */ 1131 return tls_handle_alpn(s); 1132 } 1133 1134 static int init_sig_algs(SSL *s, unsigned int context) 1135 { 1136 /* Clear any signature algorithms extension received */ 1137 OPENSSL_free(s->s3->tmp.peer_sigalgs); 1138 s->s3->tmp.peer_sigalgs = NULL; 1139 1140 return 1; 1141 } 1142 1143 static int init_sig_algs_cert(SSL *s, unsigned int context) 1144 { 1145 /* Clear any signature algorithms extension received */ 1146 OPENSSL_free(s->s3->tmp.peer_cert_sigalgs); 1147 s->s3->tmp.peer_cert_sigalgs = NULL; 1148 1149 return 1; 1150 } 1151 1152 #ifndef OPENSSL_NO_SRP 1153 static int init_srp(SSL *s, unsigned int context) 1154 { 1155 OPENSSL_free(s->srp_ctx.login); 1156 s->srp_ctx.login = NULL; 1157 1158 return 1; 1159 } 1160 #endif 1161 1162 static int init_etm(SSL *s, unsigned int context) 1163 { 1164 s->ext.use_etm = 0; 1165 1166 return 1; 1167 } 1168 1169 static int init_ems(SSL *s, unsigned int context) 1170 { 1171 if (s->s3->flags & TLS1_FLAGS_RECEIVED_EXTMS) { 1172 s->s3->flags &= ~TLS1_FLAGS_RECEIVED_EXTMS; 1173 s->s3->flags |= TLS1_FLAGS_REQUIRED_EXTMS; 1174 } 1175 1176 return 1; 1177 } 1178 1179 static int final_ems(SSL *s, unsigned int context, int sent) 1180 { 1181 /* 1182 * Check extended master secret extension is not dropped on 1183 * renegotiation. 1184 */ 1185 if (!(s->s3->flags & TLS1_FLAGS_RECEIVED_EXTMS) 1186 && (s->s3->flags & TLS1_FLAGS_REQUIRED_EXTMS)) { 1187 SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_F_FINAL_EMS, 1188 SSL_R_INCONSISTENT_EXTMS); 1189 return 0; 1190 } 1191 if (!s->server && s->hit) { 1192 /* 1193 * Check extended master secret extension is consistent with 1194 * original session. 1195 */ 1196 if (!(s->s3->flags & TLS1_FLAGS_RECEIVED_EXTMS) != 1197 !(s->session->flags & SSL_SESS_FLAG_EXTMS)) { 1198 SSLfatal(s, SSL_AD_HANDSHAKE_FAILURE, SSL_F_FINAL_EMS, 1199 SSL_R_INCONSISTENT_EXTMS); 1200 return 0; 1201 } 1202 } 1203 1204 return 1; 1205 } 1206 1207 static int init_certificate_authorities(SSL *s, unsigned int context) 1208 { 1209 sk_X509_NAME_pop_free(s->s3->tmp.peer_ca_names, X509_NAME_free); 1210 s->s3->tmp.peer_ca_names = NULL; 1211 return 1; 1212 } 1213 1214 static EXT_RETURN tls_construct_certificate_authorities(SSL *s, WPACKET *pkt, 1215 unsigned int context, 1216 X509 *x, 1217 size_t chainidx) 1218 { 1219 const STACK_OF(X509_NAME) *ca_sk = get_ca_names(s); 1220 1221 if (ca_sk == NULL || sk_X509_NAME_num(ca_sk) == 0) 1222 return EXT_RETURN_NOT_SENT; 1223 1224 if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_certificate_authorities) 1225 || !WPACKET_start_sub_packet_u16(pkt)) { 1226 SSLfatal(s, SSL_AD_INTERNAL_ERROR, 1227 SSL_F_TLS_CONSTRUCT_CERTIFICATE_AUTHORITIES, 1228 ERR_R_INTERNAL_ERROR); 1229 return EXT_RETURN_FAIL; 1230 } 1231 1232 if (!construct_ca_names(s, ca_sk, pkt)) { 1233 /* SSLfatal() already called */ 1234 return EXT_RETURN_FAIL; 1235 } 1236 1237 if (!WPACKET_close(pkt)) { 1238 SSLfatal(s, SSL_AD_INTERNAL_ERROR, 1239 SSL_F_TLS_CONSTRUCT_CERTIFICATE_AUTHORITIES, 1240 ERR_R_INTERNAL_ERROR); 1241 return EXT_RETURN_FAIL; 1242 } 1243 1244 return EXT_RETURN_SENT; 1245 } 1246 1247 static int tls_parse_certificate_authorities(SSL *s, PACKET *pkt, 1248 unsigned int context, X509 *x, 1249 size_t chainidx) 1250 { 1251 if (!parse_ca_names(s, pkt)) 1252 return 0; 1253 if (PACKET_remaining(pkt) != 0) { 1254 SSLfatal(s, SSL_AD_DECODE_ERROR, 1255 SSL_F_TLS_PARSE_CERTIFICATE_AUTHORITIES, SSL_R_BAD_EXTENSION); 1256 return 0; 1257 } 1258 return 1; 1259 } 1260 1261 #ifndef OPENSSL_NO_SRTP 1262 static int init_srtp(SSL *s, unsigned int context) 1263 { 1264 if (s->server) 1265 s->srtp_profile = NULL; 1266 1267 return 1; 1268 } 1269 #endif 1270 1271 static int final_sig_algs(SSL *s, unsigned int context, int sent) 1272 { 1273 if (!sent && SSL_IS_TLS13(s) && !s->hit) { 1274 SSLfatal(s, TLS13_AD_MISSING_EXTENSION, SSL_F_FINAL_SIG_ALGS, 1275 SSL_R_MISSING_SIGALGS_EXTENSION); 1276 return 0; 1277 } 1278 1279 return 1; 1280 } 1281 1282 #ifndef OPENSSL_NO_EC 1283 static int final_key_share(SSL *s, unsigned int context, int sent) 1284 { 1285 if (!SSL_IS_TLS13(s)) 1286 return 1; 1287 1288 /* Nothing to do for key_share in an HRR */ 1289 if ((context & SSL_EXT_TLS1_3_HELLO_RETRY_REQUEST) != 0) 1290 return 1; 1291 1292 /* 1293 * If 1294 * we are a client 1295 * AND 1296 * we have no key_share 1297 * AND 1298 * (we are not resuming 1299 * OR the kex_mode doesn't allow non key_share resumes) 1300 * THEN 1301 * fail; 1302 */ 1303 if (!s->server 1304 && !sent 1305 && (!s->hit 1306 || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE) == 0)) { 1307 /* Nothing left we can do - just fail */ 1308 SSLfatal(s, SSL_AD_MISSING_EXTENSION, SSL_F_FINAL_KEY_SHARE, 1309 SSL_R_NO_SUITABLE_KEY_SHARE); 1310 return 0; 1311 } 1312 /* 1313 * IF 1314 * we are a server 1315 * THEN 1316 * IF 1317 * we have a suitable key_share 1318 * THEN 1319 * IF 1320 * we are stateless AND we have no cookie 1321 * THEN 1322 * send a HelloRetryRequest 1323 * ELSE 1324 * IF 1325 * we didn't already send a HelloRetryRequest 1326 * AND 1327 * the client sent a key_share extension 1328 * AND 1329 * (we are not resuming 1330 * OR the kex_mode allows key_share resumes) 1331 * AND 1332 * a shared group exists 1333 * THEN 1334 * send a HelloRetryRequest 1335 * ELSE IF 1336 * we are not resuming 1337 * OR 1338 * the kex_mode doesn't allow non key_share resumes 1339 * THEN 1340 * fail 1341 * ELSE IF 1342 * we are stateless AND we have no cookie 1343 * THEN 1344 * send a HelloRetryRequest 1345 */ 1346 if (s->server) { 1347 if (s->s3->peer_tmp != NULL) { 1348 /* We have a suitable key_share */ 1349 if ((s->s3->flags & TLS1_FLAGS_STATELESS) != 0 1350 && !s->ext.cookieok) { 1351 if (!ossl_assert(s->hello_retry_request == SSL_HRR_NONE)) { 1352 /* 1353 * If we are stateless then we wouldn't know about any 1354 * previously sent HRR - so how can this be anything other 1355 * than 0? 1356 */ 1357 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_FINAL_KEY_SHARE, 1358 ERR_R_INTERNAL_ERROR); 1359 return 0; 1360 } 1361 s->hello_retry_request = SSL_HRR_PENDING; 1362 return 1; 1363 } 1364 } else { 1365 /* No suitable key_share */ 1366 if (s->hello_retry_request == SSL_HRR_NONE && sent 1367 && (!s->hit 1368 || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE_DHE) 1369 != 0)) { 1370 const uint16_t *pgroups, *clntgroups; 1371 size_t num_groups, clnt_num_groups, i; 1372 unsigned int group_id = 0; 1373 1374 /* Check if a shared group exists */ 1375 1376 /* Get the clients list of supported groups. */ 1377 tls1_get_peer_groups(s, &clntgroups, &clnt_num_groups); 1378 tls1_get_supported_groups(s, &pgroups, &num_groups); 1379 1380 /* 1381 * Find the first group we allow that is also in client's list 1382 */ 1383 for (i = 0; i < num_groups; i++) { 1384 group_id = pgroups[i]; 1385 1386 if (check_in_list(s, group_id, clntgroups, clnt_num_groups, 1387 1)) 1388 break; 1389 } 1390 1391 if (i < num_groups) { 1392 /* A shared group exists so send a HelloRetryRequest */ 1393 s->s3->group_id = group_id; 1394 s->hello_retry_request = SSL_HRR_PENDING; 1395 return 1; 1396 } 1397 } 1398 if (!s->hit 1399 || (s->ext.psk_kex_mode & TLSEXT_KEX_MODE_FLAG_KE) == 0) { 1400 /* Nothing left we can do - just fail */ 1401 SSLfatal(s, sent ? SSL_AD_HANDSHAKE_FAILURE 1402 : SSL_AD_MISSING_EXTENSION, 1403 SSL_F_FINAL_KEY_SHARE, SSL_R_NO_SUITABLE_KEY_SHARE); 1404 return 0; 1405 } 1406 1407 if ((s->s3->flags & TLS1_FLAGS_STATELESS) != 0 1408 && !s->ext.cookieok) { 1409 if (!ossl_assert(s->hello_retry_request == SSL_HRR_NONE)) { 1410 /* 1411 * If we are stateless then we wouldn't know about any 1412 * previously sent HRR - so how can this be anything other 1413 * than 0? 1414 */ 1415 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_FINAL_KEY_SHARE, 1416 ERR_R_INTERNAL_ERROR); 1417 return 0; 1418 } 1419 s->hello_retry_request = SSL_HRR_PENDING; 1420 return 1; 1421 } 1422 } 1423 1424 /* 1425 * We have a key_share so don't send any more HelloRetryRequest 1426 * messages 1427 */ 1428 if (s->hello_retry_request == SSL_HRR_PENDING) 1429 s->hello_retry_request = SSL_HRR_COMPLETE; 1430 } else { 1431 /* 1432 * For a client side resumption with no key_share we need to generate 1433 * the handshake secret (otherwise this is done during key_share 1434 * processing). 1435 */ 1436 if (!sent && !tls13_generate_handshake_secret(s, NULL, 0)) { 1437 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_FINAL_KEY_SHARE, 1438 ERR_R_INTERNAL_ERROR); 1439 return 0; 1440 } 1441 } 1442 1443 return 1; 1444 } 1445 #endif 1446 1447 static int init_psk_kex_modes(SSL *s, unsigned int context) 1448 { 1449 s->ext.psk_kex_mode = TLSEXT_KEX_MODE_FLAG_NONE; 1450 return 1; 1451 } 1452 1453 int tls_psk_do_binder(SSL *s, const EVP_MD *md, const unsigned char *msgstart, 1454 size_t binderoffset, const unsigned char *binderin, 1455 unsigned char *binderout, SSL_SESSION *sess, int sign, 1456 int external) 1457 { 1458 EVP_PKEY *mackey = NULL; 1459 EVP_MD_CTX *mctx = NULL; 1460 unsigned char hash[EVP_MAX_MD_SIZE], binderkey[EVP_MAX_MD_SIZE]; 1461 unsigned char finishedkey[EVP_MAX_MD_SIZE], tmpbinder[EVP_MAX_MD_SIZE]; 1462 unsigned char *early_secret; 1463 #ifdef CHARSET_EBCDIC 1464 static const unsigned char resumption_label[] = { 0x72, 0x65, 0x73, 0x20, 0x62, 0x69, 0x6E, 0x64, 0x65, 0x72, 0x00 }; 1465 static const unsigned char external_label[] = { 0x65, 0x78, 0x74, 0x20, 0x62, 0x69, 0x6E, 0x64, 0x65, 0x72, 0x00 }; 1466 #else 1467 static const unsigned char resumption_label[] = "res binder"; 1468 static const unsigned char external_label[] = "ext binder"; 1469 #endif 1470 const unsigned char *label; 1471 size_t bindersize, labelsize, hashsize; 1472 int hashsizei = EVP_MD_size(md); 1473 int ret = -1; 1474 int usepskfored = 0; 1475 1476 /* Ensure cast to size_t is safe */ 1477 if (!ossl_assert(hashsizei >= 0)) { 1478 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PSK_DO_BINDER, 1479 ERR_R_INTERNAL_ERROR); 1480 goto err; 1481 } 1482 hashsize = (size_t)hashsizei; 1483 1484 if (external 1485 && s->early_data_state == SSL_EARLY_DATA_CONNECTING 1486 && s->session->ext.max_early_data == 0 1487 && sess->ext.max_early_data > 0) 1488 usepskfored = 1; 1489 1490 if (external) { 1491 label = external_label; 1492 labelsize = sizeof(external_label) - 1; 1493 } else { 1494 label = resumption_label; 1495 labelsize = sizeof(resumption_label) - 1; 1496 } 1497 1498 /* 1499 * Generate the early_secret. On the server side we've selected a PSK to 1500 * resume with (internal or external) so we always do this. On the client 1501 * side we do this for a non-external (i.e. resumption) PSK or external PSK 1502 * that will be used for early_data so that it is in place for sending early 1503 * data. For client side external PSK not being used for early_data we 1504 * generate it but store it away for later use. 1505 */ 1506 if (s->server || !external || usepskfored) 1507 early_secret = (unsigned char *)s->early_secret; 1508 else 1509 early_secret = (unsigned char *)sess->early_secret; 1510 1511 if (!tls13_generate_secret(s, md, NULL, sess->master_key, 1512 sess->master_key_length, early_secret)) { 1513 /* SSLfatal() already called */ 1514 goto err; 1515 } 1516 1517 /* 1518 * Create the handshake hash for the binder key...the messages so far are 1519 * empty! 1520 */ 1521 mctx = EVP_MD_CTX_new(); 1522 if (mctx == NULL 1523 || EVP_DigestInit_ex(mctx, md, NULL) <= 0 1524 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) { 1525 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PSK_DO_BINDER, 1526 ERR_R_INTERNAL_ERROR); 1527 goto err; 1528 } 1529 1530 /* Generate the binder key */ 1531 if (!tls13_hkdf_expand(s, md, early_secret, label, labelsize, hash, 1532 hashsize, binderkey, hashsize, 1)) { 1533 /* SSLfatal() already called */ 1534 goto err; 1535 } 1536 1537 /* Generate the finished key */ 1538 if (!tls13_derive_finishedkey(s, md, binderkey, finishedkey, hashsize)) { 1539 /* SSLfatal() already called */ 1540 goto err; 1541 } 1542 1543 if (EVP_DigestInit_ex(mctx, md, NULL) <= 0) { 1544 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PSK_DO_BINDER, 1545 ERR_R_INTERNAL_ERROR); 1546 goto err; 1547 } 1548 1549 /* 1550 * Get a hash of the ClientHello up to the start of the binders. If we are 1551 * following a HelloRetryRequest then this includes the hash of the first 1552 * ClientHello and the HelloRetryRequest itself. 1553 */ 1554 if (s->hello_retry_request == SSL_HRR_PENDING) { 1555 size_t hdatalen; 1556 long hdatalen_l; 1557 void *hdata; 1558 1559 hdatalen = hdatalen_l = 1560 BIO_get_mem_data(s->s3->handshake_buffer, &hdata); 1561 if (hdatalen_l <= 0) { 1562 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PSK_DO_BINDER, 1563 SSL_R_BAD_HANDSHAKE_LENGTH); 1564 goto err; 1565 } 1566 1567 /* 1568 * For servers the handshake buffer data will include the second 1569 * ClientHello - which we don't want - so we need to take that bit off. 1570 */ 1571 if (s->server) { 1572 PACKET hashprefix, msg; 1573 1574 /* Find how many bytes are left after the first two messages */ 1575 if (!PACKET_buf_init(&hashprefix, hdata, hdatalen) 1576 || !PACKET_forward(&hashprefix, 1) 1577 || !PACKET_get_length_prefixed_3(&hashprefix, &msg) 1578 || !PACKET_forward(&hashprefix, 1) 1579 || !PACKET_get_length_prefixed_3(&hashprefix, &msg)) { 1580 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PSK_DO_BINDER, 1581 ERR_R_INTERNAL_ERROR); 1582 goto err; 1583 } 1584 hdatalen -= PACKET_remaining(&hashprefix); 1585 } 1586 1587 if (EVP_DigestUpdate(mctx, hdata, hdatalen) <= 0) { 1588 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PSK_DO_BINDER, 1589 ERR_R_INTERNAL_ERROR); 1590 goto err; 1591 } 1592 } 1593 1594 if (EVP_DigestUpdate(mctx, msgstart, binderoffset) <= 0 1595 || EVP_DigestFinal_ex(mctx, hash, NULL) <= 0) { 1596 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PSK_DO_BINDER, 1597 ERR_R_INTERNAL_ERROR); 1598 goto err; 1599 } 1600 1601 mackey = EVP_PKEY_new_raw_private_key(EVP_PKEY_HMAC, NULL, finishedkey, 1602 hashsize); 1603 if (mackey == NULL) { 1604 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PSK_DO_BINDER, 1605 ERR_R_INTERNAL_ERROR); 1606 goto err; 1607 } 1608 1609 if (!sign) 1610 binderout = tmpbinder; 1611 1612 bindersize = hashsize; 1613 if (EVP_DigestSignInit(mctx, NULL, md, NULL, mackey) <= 0 1614 || EVP_DigestSignUpdate(mctx, hash, hashsize) <= 0 1615 || EVP_DigestSignFinal(mctx, binderout, &bindersize) <= 0 1616 || bindersize != hashsize) { 1617 SSLfatal(s, SSL_AD_INTERNAL_ERROR, SSL_F_TLS_PSK_DO_BINDER, 1618 ERR_R_INTERNAL_ERROR); 1619 goto err; 1620 } 1621 1622 if (sign) { 1623 ret = 1; 1624 } else { 1625 /* HMAC keys can't do EVP_DigestVerify* - use CRYPTO_memcmp instead */ 1626 ret = (CRYPTO_memcmp(binderin, binderout, hashsize) == 0); 1627 if (!ret) 1628 SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_TLS_PSK_DO_BINDER, 1629 SSL_R_BINDER_DOES_NOT_VERIFY); 1630 } 1631 1632 err: 1633 OPENSSL_cleanse(binderkey, sizeof(binderkey)); 1634 OPENSSL_cleanse(finishedkey, sizeof(finishedkey)); 1635 EVP_PKEY_free(mackey); 1636 EVP_MD_CTX_free(mctx); 1637 1638 return ret; 1639 } 1640 1641 static int final_early_data(SSL *s, unsigned int context, int sent) 1642 { 1643 if (!sent) 1644 return 1; 1645 1646 if (!s->server) { 1647 if (context == SSL_EXT_TLS1_3_ENCRYPTED_EXTENSIONS 1648 && sent 1649 && !s->ext.early_data_ok) { 1650 /* 1651 * If we get here then the server accepted our early_data but we 1652 * later realised that it shouldn't have done (e.g. inconsistent 1653 * ALPN) 1654 */ 1655 SSLfatal(s, SSL_AD_ILLEGAL_PARAMETER, SSL_F_FINAL_EARLY_DATA, 1656 SSL_R_BAD_EARLY_DATA); 1657 return 0; 1658 } 1659 1660 return 1; 1661 } 1662 1663 if (s->max_early_data == 0 1664 || !s->hit 1665 || s->early_data_state != SSL_EARLY_DATA_ACCEPTING 1666 || !s->ext.early_data_ok 1667 || s->hello_retry_request != SSL_HRR_NONE 1668 || (s->allow_early_data_cb != NULL 1669 && !s->allow_early_data_cb(s, 1670 s->allow_early_data_cb_data))) { 1671 s->ext.early_data = SSL_EARLY_DATA_REJECTED; 1672 } else { 1673 s->ext.early_data = SSL_EARLY_DATA_ACCEPTED; 1674 1675 if (!tls13_change_cipher_state(s, 1676 SSL3_CC_EARLY | SSL3_CHANGE_CIPHER_SERVER_READ)) { 1677 /* SSLfatal() already called */ 1678 return 0; 1679 } 1680 } 1681 1682 return 1; 1683 } 1684 1685 static int final_maxfragmentlen(SSL *s, unsigned int context, int sent) 1686 { 1687 /* 1688 * Session resumption on server-side with MFL extension active 1689 * BUT MFL extension packet was not resent (i.e. sent == 0) 1690 */ 1691 if (s->server && s->hit && USE_MAX_FRAGMENT_LENGTH_EXT(s->session) 1692 && !sent ) { 1693 SSLfatal(s, SSL_AD_MISSING_EXTENSION, SSL_F_FINAL_MAXFRAGMENTLEN, 1694 SSL_R_BAD_EXTENSION); 1695 return 0; 1696 } 1697 1698 /* Current SSL buffer is lower than requested MFL */ 1699 if (s->session && USE_MAX_FRAGMENT_LENGTH_EXT(s->session) 1700 && s->max_send_fragment < GET_MAX_FRAGMENT_LENGTH(s->session)) 1701 /* trigger a larger buffer reallocation */ 1702 if (!ssl3_setup_buffers(s)) { 1703 /* SSLfatal() already called */ 1704 return 0; 1705 } 1706 1707 return 1; 1708 } 1709 1710 static int init_post_handshake_auth(SSL *s, unsigned int context) 1711 { 1712 s->post_handshake_auth = SSL_PHA_NONE; 1713 1714 return 1; 1715 } 1716