contrib/ldns/dane.c

   1 /*
   2  * Verify or create TLS authentication with DANE (RFC6698)
   3  *
   4  * (c) NLnetLabs 2012-2020
   5  *
   6  * See the file LICENSE for the license.
   7  *
   8  */
   9
  10 #include <ldns/config.h>
  11 #ifdef USE_DANE
  12
  13 #include <ldns/ldns.h>
  14 #include <ldns/dane.h>
  15
  16 #include <unistd.h>
  17 #include <stdlib.h>
  18 #include <sys/types.h>
  19 #ifdef HAVE_SYS_SOCKET_H
  20 #include <sys/socket.h>
  21 #endif
  22 #ifdef HAVE_NETDB_H
  23 #include <netdb.h>
  24 #endif
  25
  26 #ifdef HAVE_SSL
  27 #include <openssl/ssl.h>
  28 #include <openssl/err.h>
  29 #include <openssl/x509v3.h>
  30 #endif
  31
  32 /* OpenSSL context options. At the moment, disable SSLv2, SSLv3
  33  * and Compression, if available. TLSv1.0 is allowed at the moment.
  34  * TLSv1.1 is the first to provide elliptic curves, so it is usually
  35  * allowed in a TLS stack. TLSv1.2 is the first to provide authentication
  36  * modes of operation, like GCM. The defines below are a moving
  37  * target based on OpenSSL library version. Grep is useful to find
  38  * the defines: grep -IR SSL_OP_NO_ /usr/include/openssl.
  39  */
  40 #ifdef HAVE_SSL
  41 # ifdef SSL_OP_NO_SSLv2
  42         const long NoOpenSSLv2 = SSL_OP_NO_SSLv2;
  43 # else
  44         const long NoOpenSSLv2 = 0L;
  45 # endif
  46 # ifdef SSL_OP_NO_SSLv3
  47         const long NoOpenSSLv3 = SSL_OP_NO_SSLv3;
  48 # else
  49         const long NoOpenSSLv3 = 0L;
  50 # endif
  51 # ifdef SSL_OP_NO_TLSv1
  52         const long NoOpenTLSv1 = SSL_OP_NO_TLSv1;
  53 # else
  54         const long NoOpenTLSv1 = 0L;
  55 # endif
  56 # ifdef SSL_OP_NO_DTLSv1
  57         const long NoOpenDTLSv1 = SSL_OP_NO_DTLSv1;
  58 # else
  59         const long NoOpenDTLSv1 = 0L;
  60 # endif
  61 # ifdef SSL_OP_NO_COMPRESSION
  62         const long NoOpenSSLCompression = SSL_OP_NO_COMPRESSION;
  63 # else
  64         const long NoOpenSSLCompression = 0L;
  65 # endif
  66 #endif
  67
  68 #if defined(USE_DANE_VERIFY) && defined(USE_DANE_TA_USAGE)
  69 static SSL_CTX*
  70 ldns_dane_new_ssl_context(void)
  71 {
  72         SSL_CTX* ssl_ctx;
  73
  74         ssl_ctx = SSL_CTX_new(TLS_client_method());
  75         if (ssl_ctx != NULL)
  76         {
  77                 /* ldns allows TLS and DTLS v1.0 at the moment. Some may disagree.
  78                  * Sometime in the future they may be disabled, too. Maybe
  79                  * --disable-tlsv1 and --disable-dtlsv1 should be configure options.
  80                  */
  81                 long flags = NoOpenSSLv2 | NoOpenSSLv3 | NoOpenSSLCompression;
  82                 SSL_CTX_set_options(ssl_ctx, flags);
  83         }
  84
  85         return ssl_ctx;
  86 }
  87 #endif
  88
  89 ldns_status
  90 ldns_dane_create_tlsa_owner(ldns_rdf** tlsa_owner, const ldns_rdf* name,
  91                 uint16_t port, ldns_dane_transport transport)
  92 {
  93         char buf[LDNS_MAX_DOMAINLEN];
  94         size_t s;
  95
  96         assert(tlsa_owner != NULL);
  97         assert(name != NULL);
  98         assert(ldns_rdf_get_type(name) == LDNS_RDF_TYPE_DNAME);
  99
 100         s = (size_t)snprintf(buf, LDNS_MAX_DOMAINLEN, "X_%d", (int)port);
 101         buf[0] = (char)(s - 1);
 102
 103         switch(transport) {
 104         case LDNS_DANE_TRANSPORT_TCP:
 105                 s += snprintf(buf + s, LDNS_MAX_DOMAINLEN - s, "\004_tcp");
 106                 break;
 107
 108         case LDNS_DANE_TRANSPORT_UDP:
 109                 s += snprintf(buf + s, LDNS_MAX_DOMAINLEN - s, "\004_udp");
 110                 break;
 111
 112         case LDNS_DANE_TRANSPORT_SCTP:
 113                 s += snprintf(buf + s, LDNS_MAX_DOMAINLEN - s, "\005_sctp");
 114                 break;
 115
 116         default:
 117                 return LDNS_STATUS_DANE_UNKNOWN_TRANSPORT;
 118         }
 119         if (s + ldns_rdf_size(name) > LDNS_MAX_DOMAINLEN) {
 120                 return LDNS_STATUS_DOMAINNAME_OVERFLOW;
 121         }
 122         memcpy(buf + s, ldns_rdf_data(name), ldns_rdf_size(name));
 123         *tlsa_owner = ldns_rdf_new_frm_data(LDNS_RDF_TYPE_DNAME,
 124                         s + ldns_rdf_size(name), buf);
 125         if (*tlsa_owner == NULL) {
 126                 return LDNS_STATUS_MEM_ERR;
 127         }
 128         return LDNS_STATUS_OK;
 129 }
 130
 131
 132 #ifdef HAVE_SSL
 133 ldns_status
 134 ldns_dane_cert2rdf(ldns_rdf** rdf, X509* cert,
 135                 ldns_tlsa_selector      selector,
 136                 ldns_tlsa_matching_type matching_type)
 137 {
 138         unsigned char* buf = NULL;
 139         size_t len;
 140
 141         X509_PUBKEY* xpubkey;
 142         EVP_PKEY* epubkey;
 143
 144         unsigned char* digest;
 145
 146         assert(rdf != NULL);
 147         assert(cert != NULL);
 148
 149         switch(selector) {
 150         case LDNS_TLSA_SELECTOR_FULL_CERTIFICATE:
 151
 152                 len = (size_t)i2d_X509(cert, &buf);
 153                 break;
 154
 155         case LDNS_TLSA_SELECTOR_SUBJECTPUBLICKEYINFO:
 156
 157 #ifndef S_SPLINT_S
 158                 xpubkey = X509_get_X509_PUBKEY(cert);
 159 #endif
 160                 if (! xpubkey) {
 161                         return LDNS_STATUS_SSL_ERR;
 162                 }
 163                 epubkey = X509_PUBKEY_get(xpubkey);
 164                 if (! epubkey) {
 165                         return LDNS_STATUS_SSL_ERR;
 166                 }
 167                 len = (size_t)i2d_PUBKEY(epubkey, &buf);
 168                 break;
 169
 170         default:
 171                 return LDNS_STATUS_DANE_UNKNOWN_SELECTOR;
 172         }
 173
 174         switch(matching_type) {
 175         case LDNS_TLSA_MATCHING_TYPE_NO_HASH_USED:
 176
 177                 *rdf = ldns_rdf_new(LDNS_RDF_TYPE_HEX, len, buf);
 178
 179                 return *rdf ? LDNS_STATUS_OK : LDNS_STATUS_MEM_ERR;
 180                 break;
 181
 182         case LDNS_TLSA_MATCHING_TYPE_SHA256:
 183
 184                 digest = LDNS_XMALLOC(unsigned char, LDNS_SHA256_DIGEST_LENGTH);
 185                 if (digest == NULL) {
 186                         LDNS_FREE(buf);
 187                         return LDNS_STATUS_MEM_ERR;
 188                 }
 189                 (void) ldns_sha256(buf, (unsigned int)len, digest);
 190                 *rdf = ldns_rdf_new(LDNS_RDF_TYPE_HEX, LDNS_SHA256_DIGEST_LENGTH,
 191                                 digest);
 192                 LDNS_FREE(buf);
 193
 194                 return *rdf ? LDNS_STATUS_OK : LDNS_STATUS_MEM_ERR;
 195                 break;
 196
 197         case LDNS_TLSA_MATCHING_TYPE_SHA512:
 198
 199                 digest = LDNS_XMALLOC(unsigned char, LDNS_SHA512_DIGEST_LENGTH);
 200                 if (digest == NULL) {
 201                         LDNS_FREE(buf);
 202                         return LDNS_STATUS_MEM_ERR;
 203                 }
 204                 (void) ldns_sha512(buf, (unsigned int)len, digest);
 205                 *rdf = ldns_rdf_new(LDNS_RDF_TYPE_HEX, LDNS_SHA512_DIGEST_LENGTH,
 206                                 digest);
 207                 LDNS_FREE(buf);
 208
 209                 return *rdf ? LDNS_STATUS_OK : LDNS_STATUS_MEM_ERR;
 210                 break;
 211
 212         default:
 213                 LDNS_FREE(buf);
 214                 return LDNS_STATUS_DANE_UNKNOWN_MATCHING_TYPE;
 215         }
 216 }
 217
 218
 219 /* Ordinary PKIX validation of cert (with extra_certs to help)
 220  * against the CA's in store
 221  */
 222 static ldns_status
 223 ldns_dane_pkix_validate(X509* cert, STACK_OF(X509)* extra_certs,
 224                 X509_STORE* store)
 225 {
 226         X509_STORE_CTX* vrfy_ctx;
 227         ldns_status s;
 228
 229         if (! store) {
 230                 return LDNS_STATUS_DANE_PKIX_DID_NOT_VALIDATE;
 231         }
 232         vrfy_ctx = X509_STORE_CTX_new();
 233         if (! vrfy_ctx) {
 234
 235                 return LDNS_STATUS_SSL_ERR;
 236
 237         } else if (X509_STORE_CTX_init(vrfy_ctx, store,
 238                                 cert, extra_certs) != 1) {
 239                 s = LDNS_STATUS_SSL_ERR;
 240
 241         } else if (X509_verify_cert(vrfy_ctx) == 1) {
 242
 243                 s = LDNS_STATUS_OK;
 244
 245         } else {
 246                 s = LDNS_STATUS_DANE_PKIX_DID_NOT_VALIDATE;
 247         }
 248         X509_STORE_CTX_free(vrfy_ctx);
 249         return s;
 250 }
 251
 252
 253 /* Ordinary PKIX validation of cert (with extra_certs to help)
 254  * against the CA's in store, but also return the validation chain.
 255  */
 256 static ldns_status
 257 ldns_dane_pkix_validate_and_get_chain(STACK_OF(X509)** chain, X509* cert,
 258                 STACK_OF(X509)* extra_certs, X509_STORE* store)
 259 {
 260         ldns_status s;
 261         X509_STORE* empty_store = NULL;
 262         X509_STORE_CTX* vrfy_ctx;
 263
 264         assert(chain != NULL);
 265
 266         if (! store) {
 267                 store = empty_store = X509_STORE_new();
 268         }
 269         s = LDNS_STATUS_SSL_ERR;
 270         vrfy_ctx = X509_STORE_CTX_new();
 271         if (! vrfy_ctx) {
 272
 273                 goto exit_free_empty_store;
 274
 275         } else if (X509_STORE_CTX_init(vrfy_ctx, store,
 276                                         cert, extra_certs) != 1) {
 277                 goto exit_free_vrfy_ctx;
 278
 279         } else if (X509_verify_cert(vrfy_ctx) == 1) {
 280
 281                 s = LDNS_STATUS_OK;
 282
 283         } else {
 284                 s = LDNS_STATUS_DANE_PKIX_DID_NOT_VALIDATE;
 285         }
 286         *chain = X509_STORE_CTX_get1_chain(vrfy_ctx);
 287         if (! *chain) {
 288                 s = LDNS_STATUS_SSL_ERR;
 289         }
 290
 291 exit_free_vrfy_ctx:
 292         X509_STORE_CTX_free(vrfy_ctx);
 293
 294 exit_free_empty_store:
 295         if (empty_store) {
 296                 X509_STORE_free(empty_store);
 297         }
 298         return s;
 299 }
 300
 301
 302 /* Return the validation chain that can be build out of cert, with extra_certs.
 303  */
 304 static ldns_status
 305 ldns_dane_pkix_get_chain(STACK_OF(X509)** chain,
 306                 X509* cert, STACK_OF(X509)* extra_certs)
 307 {
 308         ldns_status s;
 309         X509_STORE* empty_store = NULL;
 310         X509_STORE_CTX* vrfy_ctx;
 311
 312         assert(chain != NULL);
 313
 314         empty_store = X509_STORE_new();
 315         s = LDNS_STATUS_SSL_ERR;
 316         vrfy_ctx = X509_STORE_CTX_new();
 317         if (! vrfy_ctx) {
 318
 319                 goto exit_free_empty_store;
 320
 321         } else if (X509_STORE_CTX_init(vrfy_ctx, empty_store,
 322                                         cert, extra_certs) != 1) {
 323                 goto exit_free_vrfy_ctx;
 324         }
 325         (void) X509_verify_cert(vrfy_ctx);
 326         *chain = X509_STORE_CTX_get1_chain(vrfy_ctx);
 327         if (! *chain) {
 328                 s = LDNS_STATUS_SSL_ERR;
 329         } else {
 330                 s = LDNS_STATUS_OK;
 331         }
 332 exit_free_vrfy_ctx:
 333         X509_STORE_CTX_free(vrfy_ctx);
 334
 335 exit_free_empty_store:
 336         X509_STORE_free(empty_store);
 337         return s;
 338 }
 339
 340
 341 /* Pop n+1 certs and return the last popped.
 342  */
 343 static ldns_status
 344 ldns_dane_get_nth_cert_from_validation_chain(
 345                 X509** cert, STACK_OF(X509)* chain, int n, bool ca)
 346 {
 347         if (n >= sk_X509_num(chain) || n < 0) {
 348                 return LDNS_STATUS_DANE_OFFSET_OUT_OF_RANGE;
 349         }
 350         *cert = sk_X509_pop(chain);
 351         while (n-- > 0) {
 352                 X509_free(*cert);
 353                 *cert = sk_X509_pop(chain);
 354         }
 355         if (ca && ! X509_check_ca(*cert)) {
 356                 return LDNS_STATUS_DANE_NON_CA_CERTIFICATE;
 357         }
 358         return LDNS_STATUS_OK;
 359 }
 360
 361
 362 /* Create validation chain with cert and extra_certs and returns the last
 363  * self-signed (if present).
 364  */
 365 static ldns_status
 366 ldns_dane_pkix_get_last_self_signed(X509** out_cert,
 367                 X509* cert, STACK_OF(X509)* extra_certs)
 368 {
 369         ldns_status s;
 370         X509_STORE* empty_store = NULL;
 371         X509_STORE_CTX* vrfy_ctx;
 372
 373         assert(out_cert != NULL);
 374
 375         empty_store = X509_STORE_new();
 376         s = LDNS_STATUS_SSL_ERR;
 377         vrfy_ctx = X509_STORE_CTX_new();
 378         if (! vrfy_ctx) {
 379                 goto exit_free_empty_store;
 380
 381         } else if (X509_STORE_CTX_init(vrfy_ctx, empty_store,
 382                                         cert, extra_certs) != 1) {
 383                 goto exit_free_vrfy_ctx;
 384
 385         }
 386         (void) X509_verify_cert(vrfy_ctx);
 387         if (X509_STORE_CTX_get_error(vrfy_ctx) == X509_V_ERR_SELF_SIGNED_CERT_IN_CHAIN ||
 388             X509_STORE_CTX_get_error(vrfy_ctx) == X509_V_ERR_DEPTH_ZERO_SELF_SIGNED_CERT){
 389
 390                 *out_cert = X509_STORE_CTX_get_current_cert( vrfy_ctx);
 391                 s = LDNS_STATUS_OK;
 392         } else {
 393                 s = LDNS_STATUS_DANE_PKIX_NO_SELF_SIGNED_TRUST_ANCHOR;
 394         }
 395 exit_free_vrfy_ctx:
 396         X509_STORE_CTX_free(vrfy_ctx);
 397
 398 exit_free_empty_store:
 399         X509_STORE_free(empty_store);
 400         return s;
 401 }
 402
 403
 404 ldns_status
 405 ldns_dane_select_certificate(X509** selected_cert,
 406                 X509* cert, STACK_OF(X509)* extra_certs,
 407                 X509_STORE* pkix_validation_store,
 408                 ldns_tlsa_certificate_usage cert_usage, int offset)
 409 {
 410         ldns_status s;
 411         STACK_OF(X509)* pkix_validation_chain = NULL;
 412
 413         assert(selected_cert != NULL);
 414         assert(cert != NULL);
 415
 416         /* With PKIX validation explicitly turned off (pkix_validation_store
 417          *  == NULL), treat the "CA constraint" and "Service certificate
 418          * constraint" the same as "Trust anchor assertion" and "Domain issued
 419          * certificate" respectively.
 420          */
 421         if (pkix_validation_store == NULL) {
 422                 switch (cert_usage) {
 423
 424                 case LDNS_TLSA_USAGE_CA_CONSTRAINT:
 425
 426                         cert_usage = LDNS_TLSA_USAGE_TRUST_ANCHOR_ASSERTION;
 427                         break;
 428
 429                 case LDNS_TLSA_USAGE_SERVICE_CERTIFICATE_CONSTRAINT:
 430
 431                         cert_usage = LDNS_TLSA_USAGE_DOMAIN_ISSUED_CERTIFICATE;
 432                         break;
 433
 434                 default:
 435                         break;
 436                 }
 437         }
 438
 439         /* Now what to do with each Certificate usage...
 440          */
 441         switch (cert_usage) {
 442
 443         case LDNS_TLSA_USAGE_CA_CONSTRAINT:
 444
 445                 s = ldns_dane_pkix_validate_and_get_chain(
 446                                 &pkix_validation_chain,
 447                                 cert, extra_certs,
 448                                 pkix_validation_store);
 449                 if (! pkix_validation_chain) {
 450                         return s;
 451                 }
 452                 if (s == LDNS_STATUS_OK) {
 453                         if (offset == -1) {
 454                                 offset = 0;
 455                         }
 456                         s = ldns_dane_get_nth_cert_from_validation_chain(
 457                                         selected_cert, pkix_validation_chain,
 458                                         offset, true);
 459                 }
 460                 sk_X509_pop_free(pkix_validation_chain, X509_free);
 461                 return s;
 462                 break;
 463
 464
 465         case LDNS_TLSA_USAGE_SERVICE_CERTIFICATE_CONSTRAINT:
 466
 467                 *selected_cert = cert;
 468                 return ldns_dane_pkix_validate(cert, extra_certs,
 469                                 pkix_validation_store);
 470                 break;
 471
 472
 473         case LDNS_TLSA_USAGE_TRUST_ANCHOR_ASSERTION:
 474
 475                 if (offset == -1) {
 476                         s = ldns_dane_pkix_get_last_self_signed(
 477                                         selected_cert, cert, extra_certs);
 478                         return s;
 479                 } else {
 480                         s = ldns_dane_pkix_get_chain(
 481                                         &pkix_validation_chain,
 482                                         cert, extra_certs);
 483                         if (s == LDNS_STATUS_OK) {
 484                                 s =
 485                                 ldns_dane_get_nth_cert_from_validation_chain(
 486                                         selected_cert, pkix_validation_chain,
 487                                         offset, false);
 488                         } else if (! pkix_validation_chain) {
 489                                 return s;
 490                         }
 491                         sk_X509_pop_free(pkix_validation_chain, X509_free);
 492                         return s;
 493                 }
 494                 break;
 495
 496
 497         case LDNS_TLSA_USAGE_DOMAIN_ISSUED_CERTIFICATE:
 498
 499                 *selected_cert = cert;
 500                 return LDNS_STATUS_OK;
 501                 break;
 502
 503         default:
 504                 return LDNS_STATUS_DANE_UNKNOWN_CERTIFICATE_USAGE;
 505                 break;
 506         }
 507 }
 508
 509
 510 ldns_status
 511 ldns_dane_create_tlsa_rr(ldns_rr** tlsa,
 512                 ldns_tlsa_certificate_usage certificate_usage,
 513                 ldns_tlsa_selector          selector,
 514                 ldns_tlsa_matching_type     matching_type,
 515                 X509* cert)
 516 {
 517         ldns_rdf* rdf;
 518         ldns_status s;
 519
 520         assert(tlsa != NULL);
 521         assert(cert != NULL);
 522
 523         /* create rr */
 524         *tlsa = ldns_rr_new_frm_type(LDNS_RR_TYPE_TLSA);
 525         if (*tlsa == NULL) {
 526                 return LDNS_STATUS_MEM_ERR;
 527         }
 528
 529         rdf = ldns_native2rdf_int8(LDNS_RDF_TYPE_INT8,
 530                         (uint8_t)certificate_usage);
 531         if (rdf == NULL) {
 532                 goto memerror;
 533         }
 534         (void) ldns_rr_set_rdf(*tlsa, rdf, 0);
 535
 536         rdf = ldns_native2rdf_int8(LDNS_RDF_TYPE_INT8, (uint8_t)selector);
 537         if (rdf == NULL) {
 538                 goto memerror;
 539         }
 540         (void) ldns_rr_set_rdf(*tlsa, rdf, 1);
 541
 542         rdf = ldns_native2rdf_int8(LDNS_RDF_TYPE_INT8, (uint8_t)matching_type);
 543         if (rdf == NULL) {
 544                 goto memerror;
 545         }
 546         (void) ldns_rr_set_rdf(*tlsa, rdf, 2);
 547
 548         s = ldns_dane_cert2rdf(&rdf, cert, selector, matching_type);
 549         if (s == LDNS_STATUS_OK) {
 550                 (void) ldns_rr_set_rdf(*tlsa, rdf, 3);
 551                 return LDNS_STATUS_OK;
 552         }
 553         ldns_rr_free(*tlsa);
 554         *tlsa = NULL;
 555         return s;
 556
 557 memerror:
 558         ldns_rr_free(*tlsa);
 559         *tlsa = NULL;
 560         return LDNS_STATUS_MEM_ERR;
 561 }
 562
 563
 564 #ifdef USE_DANE_VERIFY
 565 /* Return tlsas that actually are TLSA resource records with known values
 566  * for the Certificate usage, Selector and Matching type rdata fields.
 567  */
 568 static ldns_rr_list*
 569 ldns_dane_filter_unusable_records(const ldns_rr_list* tlsas)
 570 {
 571         size_t i;
 572         ldns_rr_list* r = ldns_rr_list_new();
 573         ldns_rr* tlsa_rr;
 574
 575         if (! r) {
 576                 return NULL;
 577         }
 578         for (i = 0; i < ldns_rr_list_rr_count(tlsas); i++) {
 579                 tlsa_rr = ldns_rr_list_rr(tlsas, i);
 580                 if (ldns_rr_get_type(tlsa_rr) == LDNS_RR_TYPE_TLSA &&
 581                     ldns_rr_rd_count(tlsa_rr) == 4 &&
 582                     ldns_rdf2native_int8(ldns_rr_rdf(tlsa_rr, 0)) <= 3 &&
 583                     ldns_rdf2native_int8(ldns_rr_rdf(tlsa_rr, 1)) <= 1 &&
 584                     ldns_rdf2native_int8(ldns_rr_rdf(tlsa_rr, 2)) <= 2) {
 585
 586                         if (! ldns_rr_list_push_rr(r, tlsa_rr)) {
 587                                 ldns_rr_list_free(r);
 588                                 return NULL;
 589                         }
 590                 }
 591         }
 592         return r;
 593 }
 594
 595
 596 #if !defined(USE_DANE_TA_USAGE)
 597 /* Return whether cert/selector/matching_type matches data.
 598  */
 599 static ldns_status
 600 ldns_dane_match_cert_with_data(X509* cert, ldns_tlsa_selector selector,
 601                 ldns_tlsa_matching_type matching_type, ldns_rdf* data)
 602 {
 603         ldns_status s;
 604         ldns_rdf* match_data;
 605
 606         s = ldns_dane_cert2rdf(&match_data, cert, selector, matching_type);
 607         if (s == LDNS_STATUS_OK) {
 608                 if (ldns_rdf_compare(data, match_data) != 0) {
 609                         s = LDNS_STATUS_DANE_TLSA_DID_NOT_MATCH;
 610                 }
 611                 ldns_rdf_free(match_data);
 612         }
 613         return s;
 614 }
 615
 616
 617 /* Return whether any certificate from the chain with selector/matching_type
 618  * matches data.
 619  * ca should be true if the certificate has to be a CA certificate too.
 620  */
 621 static ldns_status
 622 ldns_dane_match_any_cert_with_data(STACK_OF(X509)* chain,
 623                 ldns_tlsa_selector      selector,
 624                 ldns_tlsa_matching_type matching_type,
 625                 ldns_rdf* data, bool ca)
 626 {
 627         ldns_status s = LDNS_STATUS_DANE_TLSA_DID_NOT_MATCH;
 628         size_t n, i;
 629         X509* cert;
 630
 631         n = (size_t)sk_X509_num(chain);
 632         for (i = 0; i < n; i++) {
 633                 cert = sk_X509_pop(chain);
 634                 if (! cert) {
 635                         s = LDNS_STATUS_SSL_ERR;
 636                         break;
 637                 }
 638                 s = ldns_dane_match_cert_with_data(cert,
 639                                 selector, matching_type, data);
 640                 if (ca && s == LDNS_STATUS_OK && ! X509_check_ca(cert)) {
 641                         s = LDNS_STATUS_DANE_NON_CA_CERTIFICATE;
 642                 }
 643                 X509_free(cert);
 644                 if (s != LDNS_STATUS_DANE_TLSA_DID_NOT_MATCH) {
 645                         break;
 646                 }
 647                 /* when s == LDNS_STATUS_DANE_TLSA_DID_NOT_MATCH,
 648                  * try to match the next certificate
 649                  */
 650         }
 651         return s;
 652 }
 653 #endif /* !defined(USE_DANE_TA_USAGE) */
 654 #endif /* USE_DANE_VERIFY */
 655
 656 #ifdef USE_DANE_VERIFY
 657 ldns_status
 658 ldns_dane_verify_rr(const ldns_rr* tlsa_rr,
 659                 X509* cert, STACK_OF(X509)* extra_certs,
 660                 X509_STORE* pkix_validation_store)
 661 {
 662 #if defined(USE_DANE_TA_USAGE)
 663         SSL_CTX *ssl_ctx = NULL;
 664         SSL *ssl = NULL;
 665         X509_STORE_CTX *store_ctx = NULL;
 666 #else
 667         STACK_OF(X509)* pkix_validation_chain = NULL;
 668 #endif
 669         ldns_status s = LDNS_STATUS_OK;
 670
 671         ldns_tlsa_certificate_usage usage;
 672         ldns_tlsa_selector          selector;
 673         ldns_tlsa_matching_type     mtype;
 674         ldns_rdf*                   data;
 675
 676         if (! tlsa_rr || ldns_rr_get_type(tlsa_rr) != LDNS_RR_TYPE_TLSA ||
 677                         ldns_rr_rd_count(tlsa_rr) != 4 ||
 678                         ldns_rdf2native_int8(ldns_rr_rdf(tlsa_rr, 0)) > 3 ||
 679                         ldns_rdf2native_int8(ldns_rr_rdf(tlsa_rr, 1)) > 1 ||
 680                         ldns_rdf2native_int8(ldns_rr_rdf(tlsa_rr, 2)) > 2 ) {
 681                 /* No (usable) TLSA, so regular PKIX validation
 682                  */
 683                 return ldns_dane_pkix_validate(cert, extra_certs,
 684                                 pkix_validation_store);
 685         }
 686         usage    = ldns_rdf2native_int8(ldns_rr_rdf(tlsa_rr, 0));
 687         selector = ldns_rdf2native_int8(ldns_rr_rdf(tlsa_rr, 1));
 688         mtype    = ldns_rdf2native_int8(ldns_rr_rdf(tlsa_rr, 2));
 689         data     =                      ldns_rr_rdf(tlsa_rr, 3) ;
 690
 691 #if defined(USE_DANE_TA_USAGE)
 692         /* Rely on OpenSSL dane functions.
 693          *
 694          * OpenSSL does not provide offline dane verification.  The dane unit
 695          * tests within openssl use the undocumented SSL_get0_dane() and
 696          * X509_STORE_CTX_set0_dane() to convey dane parameters set on SSL and
 697          * SSL_CTX to a X509_STORE_CTX that can be used to do offline
 698          * verification.  We use these undocumented means with the ldns
 699          * dane function prototypes which did only offline dane verification.
 700          */
 701         if (!(ssl_ctx = ldns_dane_new_ssl_context()))
 702                 s = LDNS_STATUS_MEM_ERR;
 703
 704         else if (SSL_CTX_dane_enable(ssl_ctx) <= 0)
 705                 s = LDNS_STATUS_SSL_ERR;
 706
 707         else if (SSL_CTX_dane_set_flags(
 708                                 ssl_ctx, DANE_FLAG_NO_DANE_EE_NAMECHECKS),
 709                         !(ssl = SSL_new(ssl_ctx)))
 710                 s = LDNS_STATUS_MEM_ERR;
 711
 712         else if (SSL_set_connect_state(ssl),
 713                         (SSL_dane_enable(ssl, NULL) <= 0))
 714                 s = LDNS_STATUS_SSL_ERR;
 715
 716         else if (SSL_dane_tlsa_add(ssl, usage, selector, mtype,
 717                                 ldns_rdf_data(data), ldns_rdf_size(data)) <= 0)
 718                 s = LDNS_STATUS_SSL_ERR;
 719
 720         else if (!(store_ctx =  X509_STORE_CTX_new()))
 721                 s = LDNS_STATUS_MEM_ERR;
 722
 723         else if (!X509_STORE_CTX_init(store_ctx, pkix_validation_store, cert, extra_certs))
 724                 s = LDNS_STATUS_SSL_ERR;
 725
 726         else {
 727                 int ret;
 728
 729                 X509_STORE_CTX_set_default(store_ctx,
 730                                 SSL_is_server(ssl) ? "ssl_client" : "ssl_server");
 731                 X509_VERIFY_PARAM_set1(X509_STORE_CTX_get0_param(store_ctx),
 732                                 SSL_get0_param(ssl));
 733                 X509_STORE_CTX_set0_dane(store_ctx, SSL_get0_dane(ssl));
 734                 if (SSL_get_verify_callback(ssl))
 735                         X509_STORE_CTX_set_verify_cb(store_ctx, SSL_get_verify_callback(ssl));
 736
 737                 ret = X509_verify_cert(store_ctx);
 738                 if (!ret) {
 739                         if (X509_STORE_CTX_get_error(store_ctx) == X509_V_ERR_DANE_NO_MATCH)
 740                                 s = LDNS_STATUS_DANE_TLSA_DID_NOT_MATCH;
 741                         else
 742                                 s = LDNS_STATUS_DANE_PKIX_DID_NOT_VALIDATE;
 743                 }
 744                 X509_STORE_CTX_cleanup(store_ctx);
 745         }
 746         if (store_ctx)
 747                 X509_STORE_CTX_free(store_ctx);
 748         if (ssl)
 749                 SSL_free(ssl);
 750         if (ssl_ctx)
 751                 SSL_CTX_free(ssl_ctx);
 752         return s;
 753 #else
 754         switch (usage) {
 755         case LDNS_TLSA_USAGE_CA_CONSTRAINT:
 756                 s = ldns_dane_pkix_validate_and_get_chain(
 757                                 &pkix_validation_chain,
 758                                 cert, extra_certs,
 759                                 pkix_validation_store);
 760                 if (! pkix_validation_chain) {
 761                         return s;
 762                 }
 763                 if (s == LDNS_STATUS_DANE_PKIX_DID_NOT_VALIDATE) {
 764                         /*
 765                          * NO PKIX validation. We still try to match *any*
 766                          * certificate from the chain, so we return
 767                          * TLSA errors over PKIX errors.
 768                          *
 769                          * i.e. When the TLSA matches no certificate, we return
 770                          * TLSA_DID_NOT_MATCH and not PKIX_DID_NOT_VALIDATE
 771                          */
 772                         s = ldns_dane_match_any_cert_with_data(
 773                                         pkix_validation_chain,
 774                                         selector, mtype, data, true);
 775
 776                         if (s == LDNS_STATUS_OK) {
 777                                 /* A TLSA record did match a cert from the
 778                                  * chain, thus the error is failed PKIX
 779                                  * validation.
 780                                  */
 781                                 s = LDNS_STATUS_DANE_PKIX_DID_NOT_VALIDATE;
 782                         }
 783
 784                 } else if (s == LDNS_STATUS_OK) {
 785                         /* PKIX validated, does the TLSA match too? */
 786
 787                         s = ldns_dane_match_any_cert_with_data(
 788                                         pkix_validation_chain,
 789                                         selector, mtype, data, true);
 790                 }
 791                 sk_X509_pop_free(pkix_validation_chain, X509_free);
 792                 return s;
 793                 break;
 794
 795         case LDNS_TLSA_USAGE_SERVICE_CERTIFICATE_CONSTRAINT:
 796
 797                 s = ldns_dane_match_cert_with_data(cert,
 798                                 selector, mtype, data);
 799
 800                 if (s == LDNS_STATUS_OK) {
 801                         return ldns_dane_pkix_validate(cert, extra_certs,
 802                                         pkix_validation_store);
 803                 }
 804                 return s;
 805                 break;
 806
 807         case LDNS_TLSA_USAGE_TRUST_ANCHOR_ASSERTION:
 808 #if 0
 809                 s = ldns_dane_pkix_get_chain(&pkix_validation_chain,
 810                                 cert, extra_certs);
 811
 812                 if (s == LDNS_STATUS_OK) {
 813                         s = ldns_dane_match_any_cert_with_data(
 814                                         pkix_validation_chain,
 815                                         selector, mtype, data, false);
 816
 817                 } else if (! pkix_validation_chain) {
 818                         return s;
 819                 }
 820                 sk_X509_pop_free(pkix_validation_chain, X509_free);
 821                 return s;
 822 #else
 823                 return LDNS_STATUS_DANE_NEED_OPENSSL_GE_1_1_FOR_DANE_TA;
 824 #endif
 825                 break;
 826
 827         case LDNS_TLSA_USAGE_DOMAIN_ISSUED_CERTIFICATE:
 828                 return ldns_dane_match_cert_with_data(cert,
 829                                 selector, mtype, data);
 830                 break;
 831
 832         default:
 833                 break;
 834         }
 835 #endif
 836         return LDNS_STATUS_DANE_UNKNOWN_CERTIFICATE_USAGE;
 837 }
 838
 839
 840 ldns_status
 841 ldns_dane_verify(const ldns_rr_list* tlsas,
 842                 X509* cert, STACK_OF(X509)* extra_certs,
 843                 X509_STORE* pkix_validation_store)
 844 {
 845 #if defined(USE_DANE_TA_USAGE)
 846         SSL_CTX *ssl_ctx = NULL;
 847         ldns_rdf *basename_rdf = NULL;
 848         char *basename = NULL;
 849         SSL *ssl = NULL;
 850         X509_STORE_CTX *store_ctx = NULL;
 851 #else
 852         ldns_status ps;
 853 #endif
 854         size_t i;
 855         ldns_rr* tlsa_rr;
 856         ldns_rr_list *usable_tlsas;
 857         ldns_status s = LDNS_STATUS_OK;
 858
 859         assert(cert != NULL);
 860
 861         if (! tlsas || ldns_rr_list_rr_count(tlsas) == 0)
 862                 /* No TLSA's, so regular PKIX validation
 863                  */
 864                 return ldns_dane_pkix_validate(cert, extra_certs,
 865                                 pkix_validation_store);
 866
 867 /* To enable name checks (which we don't) */
 868 #if defined(USE_DANE_TA_USAGE) && 0
 869         else if (!(basename_rdf = ldns_dname_clone_from(
 870                                         ldns_rr_list_owner(tlsas), 2)))
 871                 /* Could nog get DANE base name */
 872                 s = LDNS_STATUS_ERR;
 873
 874         else if (!(basename = ldns_rdf2str(basename_rdf)))
 875                 s = LDNS_STATUS_MEM_ERR;
 876
 877         else if (strlen(basename) && (basename[strlen(basename)-1]  = 0))
 878                 s = LDNS_STATUS_ERR; /* Intended to be unreachable */
 879 #endif
 880
 881         else if (!(usable_tlsas = ldns_dane_filter_unusable_records(tlsas)))
 882                 return LDNS_STATUS_MEM_ERR;
 883
 884         else if (ldns_rr_list_rr_count(usable_tlsas) == 0) {
 885                 /* No TLSA's, so regular PKIX validation
 886                  */
 887                 ldns_rr_list_free(usable_tlsas);
 888                 return ldns_dane_pkix_validate(cert, extra_certs,
 889                                 pkix_validation_store);
 890         }
 891 #if defined(USE_DANE_TA_USAGE)
 892         /* Rely on OpenSSL dane functions.
 893          *
 894          * OpenSSL does not provide offline dane verification.  The dane unit
 895          * tests within openssl use the undocumented SSL_get0_dane() and
 896          * X509_STORE_CTX_set0_dane() to convey dane parameters set on SSL and
 897          * SSL_CTX to a X509_STORE_CTX that can be used to do offline
 898          * verification.  We use these undocumented means with the ldns
 899          * dane function prototypes which did only offline dane verification.
 900          */
 901         if (!(ssl_ctx = ldns_dane_new_ssl_context()))
 902                 s = LDNS_STATUS_MEM_ERR;
 903
 904         else if (SSL_CTX_dane_enable(ssl_ctx) <= 0)
 905                 s = LDNS_STATUS_SSL_ERR;
 906
 907         else if (SSL_CTX_dane_set_flags(
 908                                 ssl_ctx, DANE_FLAG_NO_DANE_EE_NAMECHECKS),
 909                         !(ssl = SSL_new(ssl_ctx)))
 910                 s = LDNS_STATUS_MEM_ERR;
 911
 912         else if (SSL_set_connect_state(ssl),
 913                         (SSL_dane_enable(ssl, basename) <= 0))
 914                 s = LDNS_STATUS_SSL_ERR;
 915
 916         else for (i = 0; i < ldns_rr_list_rr_count(usable_tlsas); i++) {
 917                 ldns_tlsa_certificate_usage usage;
 918                 ldns_tlsa_selector          selector;
 919                 ldns_tlsa_matching_type     mtype;
 920                 ldns_rdf*                   data;
 921
 922                 tlsa_rr = ldns_rr_list_rr(usable_tlsas, i);
 923                 usage   = ldns_rdf2native_int8(ldns_rr_rdf(tlsa_rr,0));
 924                 selector= ldns_rdf2native_int8(ldns_rr_rdf(tlsa_rr,1));
 925                 mtype   = ldns_rdf2native_int8(ldns_rr_rdf(tlsa_rr,2));
 926                 data    =                      ldns_rr_rdf(tlsa_rr,3) ;
 927
 928                 if (SSL_dane_tlsa_add(ssl, usage, selector, mtype,
 929                                         ldns_rdf_data(data),
 930                                         ldns_rdf_size(data)) <= 0) {
 931                         s = LDNS_STATUS_SSL_ERR;
 932                         break;
 933                 }
 934         }
 935         if (!s && !(store_ctx =  X509_STORE_CTX_new()))
 936                 s = LDNS_STATUS_MEM_ERR;
 937
 938         else if (!X509_STORE_CTX_init(store_ctx, pkix_validation_store, cert, extra_certs))
 939                 s = LDNS_STATUS_SSL_ERR;
 940
 941         else {
 942                 int ret;
 943
 944                 X509_STORE_CTX_set_default(store_ctx,
 945                                 SSL_is_server(ssl) ? "ssl_client" : "ssl_server");
 946                 X509_VERIFY_PARAM_set1(X509_STORE_CTX_get0_param(store_ctx),
 947                                 SSL_get0_param(ssl));
 948                 X509_STORE_CTX_set0_dane(store_ctx, SSL_get0_dane(ssl));
 949                 if (SSL_get_verify_callback(ssl))
 950                         X509_STORE_CTX_set_verify_cb(store_ctx, SSL_get_verify_callback(ssl));
 951
 952                 ret = X509_verify_cert(store_ctx);
 953                 if (!ret) {
 954                         if (X509_STORE_CTX_get_error(store_ctx) == X509_V_ERR_DANE_NO_MATCH)
 955                                 s = LDNS_STATUS_DANE_TLSA_DID_NOT_MATCH;
 956                         else
 957                                 s = LDNS_STATUS_DANE_PKIX_DID_NOT_VALIDATE;
 958                 }
 959                 X509_STORE_CTX_cleanup(store_ctx);
 960         }
 961         if (store_ctx)
 962                 X509_STORE_CTX_free(store_ctx);
 963         if (ssl)
 964                 SSL_free(ssl);
 965         if (ssl_ctx)
 966                 SSL_CTX_free(ssl_ctx);
 967         if (basename)
 968                 free(basename);
 969         ldns_rdf_deep_free(basename_rdf);
 970 #else
 971         for (i = 0; i < ldns_rr_list_rr_count(usable_tlsas); i++) {
 972                 tlsa_rr = ldns_rr_list_rr(usable_tlsas, i);
 973                 ps = s;
 974                 s = ldns_dane_verify_rr(tlsa_rr, cert, extra_certs,
 975                                 pkix_validation_store);
 976
 977                 if (s != LDNS_STATUS_DANE_TLSA_DID_NOT_MATCH &&
 978                     s != LDNS_STATUS_DANE_PKIX_DID_NOT_VALIDATE &&
 979                     s != LDNS_STATUS_DANE_NEED_OPENSSL_GE_1_1_FOR_DANE_TA) {
 980
 981                         /* which would be LDNS_STATUS_OK (match)
 982                          * or some fatal error preventing use from
 983                          * trying the next TLSA record.
 984                          */
 985                         break;
 986                 }
 987                 s = (s > ps ? s : ps); /* pref NEED_OPENSSL_GE_1_1_FOR_DANE_TA
 988                                         * over PKIX_DID_NOT_VALIDATE
 989                                         * over TLSA_DID_NOT_MATCH
 990                                         */
 991         }
 992 #endif
 993         ldns_rr_list_free(usable_tlsas);
 994         return s;
 995 }
 996 #endif /* USE_DANE_VERIFY */
 997 #endif /* HAVE_SSL */
 998 #endif /* USE_DANE */