1 /* $OpenBSD: ct_sct.c,v 1.10 2023/07/22 17:02:49 tb Exp $ */ 2 /* 3 * Written by Rob Stradling (rob@comodo.com), Stephen Henson (steve@openssl.org) 4 * and Adam Eijdenberg (adam.eijdenberg@gmail.com) for the OpenSSL project 2016. 5 */ 6 /* ==================================================================== 7 * Copyright (c) 2014 The OpenSSL Project. All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in 18 * the documentation and/or other materials provided with the 19 * distribution. 20 * 21 * 3. All advertising materials mentioning features or use of this 22 * software must display the following acknowledgment: 23 * "This product includes software developed by the OpenSSL Project 24 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)" 25 * 26 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to 27 * endorse or promote products derived from this software without 28 * prior written permission. For written permission, please contact 29 * licensing@OpenSSL.org. 30 * 31 * 5. Products derived from this software may not be called "OpenSSL" 32 * nor may "OpenSSL" appear in their names without prior written 33 * permission of the OpenSSL Project. 34 * 35 * 6. Redistributions of any form whatsoever must retain the following 36 * acknowledgment: 37 * "This product includes software developed by the OpenSSL Project 38 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)" 39 * 40 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY 41 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 43 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR 44 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 45 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 46 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 47 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 49 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 50 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 51 * OF THE POSSIBILITY OF SUCH DAMAGE. 52 * ==================================================================== 53 * 54 * This product includes cryptographic software written by Eric Young 55 * (eay@cryptsoft.com). This product includes software written by Tim 56 * Hudson (tjh@cryptsoft.com). 57 * 58 */ 59 60 #ifdef OPENSSL_NO_CT 61 # error "CT disabled" 62 #endif 63 64 #include <stdint.h> 65 #include <stdlib.h> 66 #include <string.h> 67 68 #include <openssl/asn1.h> 69 #include <openssl/ct.h> 70 #include <openssl/err.h> 71 #include <openssl/objects.h> 72 #include <openssl/x509.h> 73 74 #include "ct_local.h" 75 76 SCT * 77 SCT_new(void) 78 { 79 SCT *sct = calloc(1, sizeof(*sct)); 80 81 if (sct == NULL) { 82 CTerror(ERR_R_MALLOC_FAILURE); 83 return NULL; 84 } 85 86 sct->entry_type = CT_LOG_ENTRY_TYPE_NOT_SET; 87 sct->version = SCT_VERSION_NOT_SET; 88 return sct; 89 } 90 LCRYPTO_ALIAS(SCT_new); 91 92 void 93 SCT_free(SCT *sct) 94 { 95 if (sct == NULL) 96 return; 97 98 free(sct->log_id); 99 free(sct->ext); 100 free(sct->sig); 101 free(sct->sct); 102 free(sct); 103 } 104 LCRYPTO_ALIAS(SCT_free); 105 106 void 107 SCT_LIST_free(STACK_OF(SCT) *scts) 108 { 109 sk_SCT_pop_free(scts, SCT_free); 110 } 111 LCRYPTO_ALIAS(SCT_LIST_free); 112 113 int 114 SCT_set_version(SCT *sct, sct_version_t version) 115 { 116 if (version != SCT_VERSION_V1) { 117 CTerror(CT_R_UNSUPPORTED_VERSION); 118 return 0; 119 } 120 sct->version = version; 121 sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET; 122 return 1; 123 } 124 LCRYPTO_ALIAS(SCT_set_version); 125 126 int 127 SCT_set_log_entry_type(SCT *sct, ct_log_entry_type_t entry_type) 128 { 129 sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET; 130 131 switch (entry_type) { 132 case CT_LOG_ENTRY_TYPE_X509: 133 case CT_LOG_ENTRY_TYPE_PRECERT: 134 sct->entry_type = entry_type; 135 return 1; 136 case CT_LOG_ENTRY_TYPE_NOT_SET: 137 break; 138 } 139 CTerror(CT_R_UNSUPPORTED_ENTRY_TYPE); 140 return 0; 141 } 142 LCRYPTO_ALIAS(SCT_set_log_entry_type); 143 144 int 145 SCT_set0_log_id(SCT *sct, unsigned char *log_id, size_t log_id_len) 146 { 147 if (sct->version == SCT_VERSION_V1 && log_id_len != CT_V1_HASHLEN) { 148 CTerror(CT_R_INVALID_LOG_ID_LENGTH); 149 return 0; 150 } 151 152 free(sct->log_id); 153 sct->log_id = log_id; 154 sct->log_id_len = log_id_len; 155 sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET; 156 return 1; 157 } 158 LCRYPTO_ALIAS(SCT_set0_log_id); 159 160 int 161 SCT_set1_log_id(SCT *sct, const unsigned char *log_id, size_t log_id_len) 162 { 163 if (sct->version == SCT_VERSION_V1 && log_id_len != CT_V1_HASHLEN) { 164 CTerror(CT_R_INVALID_LOG_ID_LENGTH); 165 return 0; 166 } 167 168 free(sct->log_id); 169 sct->log_id = NULL; 170 sct->log_id_len = 0; 171 sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET; 172 173 if (log_id != NULL && log_id_len > 0) { 174 sct->log_id = malloc(log_id_len); 175 if (sct->log_id == NULL) { 176 CTerror(ERR_R_MALLOC_FAILURE); 177 return 0; 178 } 179 memcpy(sct->log_id, log_id, log_id_len); 180 sct->log_id_len = log_id_len; 181 } 182 return 1; 183 } 184 LCRYPTO_ALIAS(SCT_set1_log_id); 185 186 187 void 188 SCT_set_timestamp(SCT *sct, uint64_t timestamp) 189 { 190 sct->timestamp = timestamp; 191 sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET; 192 } 193 LCRYPTO_ALIAS(SCT_set_timestamp); 194 195 int 196 SCT_set_signature_nid(SCT *sct, int nid) 197 { 198 switch (nid) { 199 case NID_sha256WithRSAEncryption: 200 sct->hash_alg = 4; /* XXX */ 201 sct->sig_alg = 1; /* XXX */ 202 sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET; 203 return 1; 204 case NID_ecdsa_with_SHA256: 205 sct->hash_alg = 4; /* XXX */ 206 sct->sig_alg = 3; /* XXX */ 207 sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET; 208 return 1; 209 default: 210 CTerror(CT_R_UNRECOGNIZED_SIGNATURE_NID); 211 return 0; 212 } 213 } 214 LCRYPTO_ALIAS(SCT_set_signature_nid); 215 216 void 217 SCT_set0_extensions(SCT *sct, unsigned char *ext, size_t ext_len) 218 { 219 free(sct->ext); 220 sct->ext = ext; 221 sct->ext_len = ext_len; 222 sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET; 223 } 224 LCRYPTO_ALIAS(SCT_set0_extensions); 225 226 int 227 SCT_set1_extensions(SCT *sct, const unsigned char *ext, size_t ext_len) 228 { 229 free(sct->ext); 230 sct->ext = NULL; 231 sct->ext_len = 0; 232 sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET; 233 234 if (ext != NULL && ext_len > 0) { 235 sct->ext = malloc(ext_len); 236 if (sct->ext == NULL) { 237 CTerror(ERR_R_MALLOC_FAILURE); 238 return 0; 239 } 240 memcpy(sct->ext, ext, ext_len); 241 sct->ext_len = ext_len; 242 } 243 return 1; 244 } 245 LCRYPTO_ALIAS(SCT_set1_extensions); 246 247 void 248 SCT_set0_signature(SCT *sct, unsigned char *sig, size_t sig_len) 249 { 250 free(sct->sig); 251 sct->sig = sig; 252 sct->sig_len = sig_len; 253 sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET; 254 } 255 LCRYPTO_ALIAS(SCT_set0_signature); 256 257 int 258 SCT_set1_signature(SCT *sct, const unsigned char *sig, size_t sig_len) 259 { 260 free(sct->sig); 261 sct->sig = NULL; 262 sct->sig_len = 0; 263 sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET; 264 265 if (sig != NULL && sig_len > 0) { 266 sct->sig = malloc(sig_len); 267 if (sct->sig == NULL) { 268 CTerror(ERR_R_MALLOC_FAILURE); 269 return 0; 270 } 271 memcpy(sct->sig, sig, sig_len); 272 sct->sig_len = sig_len; 273 } 274 return 1; 275 } 276 LCRYPTO_ALIAS(SCT_set1_signature); 277 278 sct_version_t 279 SCT_get_version(const SCT *sct) 280 { 281 return sct->version; 282 } 283 LCRYPTO_ALIAS(SCT_get_version); 284 285 ct_log_entry_type_t 286 SCT_get_log_entry_type(const SCT *sct) 287 { 288 return sct->entry_type; 289 } 290 LCRYPTO_ALIAS(SCT_get_log_entry_type); 291 292 size_t 293 SCT_get0_log_id(const SCT *sct, unsigned char **log_id) 294 { 295 *log_id = sct->log_id; 296 return sct->log_id_len; 297 } 298 LCRYPTO_ALIAS(SCT_get0_log_id); 299 300 uint64_t 301 SCT_get_timestamp(const SCT *sct) 302 { 303 return sct->timestamp; 304 } 305 LCRYPTO_ALIAS(SCT_get_timestamp); 306 307 int 308 SCT_get_signature_nid(const SCT *sct) 309 { 310 if (sct->version == SCT_VERSION_V1) { 311 /* XXX sigalg numbers */ 312 if (sct->hash_alg == 4) { 313 switch (sct->sig_alg) { 314 case 3: 315 return NID_ecdsa_with_SHA256; 316 case 1: 317 return NID_sha256WithRSAEncryption; 318 default: 319 return NID_undef; 320 } 321 } 322 } 323 return NID_undef; 324 } 325 LCRYPTO_ALIAS(SCT_get_signature_nid); 326 327 size_t 328 SCT_get0_extensions(const SCT *sct, unsigned char **ext) 329 { 330 *ext = sct->ext; 331 return sct->ext_len; 332 } 333 LCRYPTO_ALIAS(SCT_get0_extensions); 334 335 size_t 336 SCT_get0_signature(const SCT *sct, unsigned char **sig) 337 { 338 *sig = sct->sig; 339 return sct->sig_len; 340 } 341 LCRYPTO_ALIAS(SCT_get0_signature); 342 343 int 344 SCT_is_complete(const SCT *sct) 345 { 346 switch (sct->version) { 347 case SCT_VERSION_NOT_SET: 348 return 0; 349 case SCT_VERSION_V1: 350 return sct->log_id != NULL && SCT_signature_is_complete(sct); 351 default: 352 return sct->sct != NULL; /* Just need cached encoding */ 353 } 354 } 355 356 int 357 SCT_signature_is_complete(const SCT *sct) 358 { 359 return SCT_get_signature_nid(sct) != NID_undef && 360 sct->sig != NULL && sct->sig_len > 0; 361 } 362 363 sct_source_t 364 SCT_get_source(const SCT *sct) 365 { 366 return sct->source; 367 } 368 LCRYPTO_ALIAS(SCT_get_source); 369 370 int 371 SCT_set_source(SCT *sct, sct_source_t source) 372 { 373 sct->source = source; 374 sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET; 375 switch (source) { 376 case SCT_SOURCE_TLS_EXTENSION: 377 case SCT_SOURCE_OCSP_STAPLED_RESPONSE: 378 return SCT_set_log_entry_type(sct, CT_LOG_ENTRY_TYPE_X509); 379 case SCT_SOURCE_X509V3_EXTENSION: 380 return SCT_set_log_entry_type(sct, CT_LOG_ENTRY_TYPE_PRECERT); 381 case SCT_SOURCE_UNKNOWN: 382 break; 383 } 384 /* if we aren't sure, leave the log entry type alone */ 385 return 1; 386 } 387 LCRYPTO_ALIAS(SCT_set_source); 388 389 sct_validation_status_t 390 SCT_get_validation_status(const SCT *sct) 391 { 392 return sct->validation_status; 393 } 394 LCRYPTO_ALIAS(SCT_get_validation_status); 395 396 int 397 SCT_validate(SCT *sct, const CT_POLICY_EVAL_CTX *ctx) 398 { 399 int is_sct_valid = -1; 400 SCT_CTX *sctx = NULL; 401 X509_PUBKEY *pub = NULL, *log_pkey = NULL; 402 const CTLOG *log; 403 404 /* 405 * With an unrecognized SCT version we don't know what such an SCT means, 406 * let alone validate one. So we return validation failure (0). 407 */ 408 if (sct->version != SCT_VERSION_V1) { 409 sct->validation_status = SCT_VALIDATION_STATUS_UNKNOWN_VERSION; 410 return 0; 411 } 412 413 log = CTLOG_STORE_get0_log_by_id(ctx->log_store, sct->log_id, 414 sct->log_id_len); 415 416 /* Similarly, an SCT from an unknown log also cannot be validated. */ 417 if (log == NULL) { 418 sct->validation_status = SCT_VALIDATION_STATUS_UNKNOWN_LOG; 419 return 0; 420 } 421 422 sctx = SCT_CTX_new(); 423 if (sctx == NULL) 424 goto err; 425 426 if (X509_PUBKEY_set(&log_pkey, CTLOG_get0_public_key(log)) != 1) 427 goto err; 428 if (SCT_CTX_set1_pubkey(sctx, log_pkey) != 1) 429 goto err; 430 431 if (SCT_get_log_entry_type(sct) == CT_LOG_ENTRY_TYPE_PRECERT) { 432 EVP_PKEY *issuer_pkey; 433 434 if (ctx->issuer == NULL) { 435 sct->validation_status = SCT_VALIDATION_STATUS_UNVERIFIED; 436 goto end; 437 } 438 439 if ((issuer_pkey = X509_get0_pubkey(ctx->issuer)) == NULL) 440 goto err; 441 442 if (X509_PUBKEY_set(&pub, issuer_pkey) != 1) 443 goto err; 444 if (SCT_CTX_set1_issuer_pubkey(sctx, pub) != 1) 445 goto err; 446 } 447 448 SCT_CTX_set_time(sctx, ctx->epoch_time_in_ms); 449 450 /* 451 * XXX: Potential for optimization. This repeats some idempotent heavy 452 * lifting on the certificate for each candidate SCT, and appears to not 453 * use any information in the SCT itself, only the certificate is 454 * processed. So it may make more sense to to do this just once, perhaps 455 * associated with the shared (by all SCTs) policy eval ctx. 456 * 457 * XXX: Failure here is global (SCT independent) and represents either an 458 * issue with the certificate (e.g. duplicate extensions) or an out of 459 * memory condition. When the certificate is incompatible with CT, we just 460 * mark the SCTs invalid, rather than report a failure to determine the 461 * validation status. That way, callbacks that want to do "soft" SCT 462 * processing will not abort handshakes with false positive internal 463 * errors. Since the function does not distinguish between certificate 464 * issues (peer's fault) and internal problems (out fault) the safe thing 465 * to do is to report a validation failure and let the callback or 466 * application decide what to do. 467 */ 468 if (SCT_CTX_set1_cert(sctx, ctx->cert, NULL) != 1) 469 sct->validation_status = SCT_VALIDATION_STATUS_UNVERIFIED; 470 else 471 sct->validation_status = SCT_CTX_verify(sctx, sct) == 1 ? 472 SCT_VALIDATION_STATUS_VALID : SCT_VALIDATION_STATUS_INVALID; 473 474 end: 475 is_sct_valid = sct->validation_status == SCT_VALIDATION_STATUS_VALID; 476 err: 477 X509_PUBKEY_free(pub); 478 X509_PUBKEY_free(log_pkey); 479 SCT_CTX_free(sctx); 480 481 return is_sct_valid; 482 } 483 LCRYPTO_ALIAS(SCT_validate); 484 485 int 486 SCT_LIST_validate(const STACK_OF(SCT) *scts, CT_POLICY_EVAL_CTX *ctx) 487 { 488 int are_scts_valid = 1; 489 int sct_count = scts != NULL ? sk_SCT_num(scts) : 0; 490 int i; 491 492 for (i = 0; i < sct_count; ++i) { 493 int is_sct_valid = -1; 494 SCT *sct = sk_SCT_value(scts, i); 495 496 if (sct == NULL) 497 continue; 498 499 is_sct_valid = SCT_validate(sct, ctx); 500 if (is_sct_valid < 0) 501 return is_sct_valid; 502 are_scts_valid &= is_sct_valid; 503 } 504 505 return are_scts_valid; 506 } 507 LCRYPTO_ALIAS(SCT_LIST_validate); 508