src/resolve/resolved-dns-trust-anchor.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include "sd-messages.h"
   4
   5 #include "alloc-util.h"
   6 #include "conf-files.h"
   7 #include "def.h"
   8 #include "dns-domain.h"
   9 #include "fd-util.h"
  10 #include "fileio.h"
  11 #include "hexdecoct.h"
  12 #include "nulstr-util.h"
  13 #include "parse-util.h"
  14 #include "resolved-dns-dnssec.h"
  15 #include "resolved-dns-trust-anchor.h"
  16 #include "set.h"
  17 #include "sort-util.h"
  18 #include "string-util.h"
  19 #include "strv.h"
  20
  21 static const char trust_anchor_dirs[] = CONF_PATHS_NULSTR("dnssec-trust-anchors.d");
  22
  23 /* The second DS RR from https://data.iana.org/root-anchors/root-anchors.xml, retrieved February 2017 */
  24 static const uint8_t root_digest2[] =
  25         { 0xE0, 0x6D, 0x44, 0xB8, 0x0B, 0x8F, 0x1D, 0x39, 0xA9, 0x5C, 0x0B, 0x0D, 0x7C, 0x65, 0xD0, 0x84,
  26           0x58, 0xE8, 0x80, 0x40, 0x9B, 0xBC, 0x68, 0x34, 0x57, 0x10, 0x42, 0x37, 0xC7, 0xF8, 0xEC, 0x8D };
  27
  28 static bool dns_trust_anchor_knows_domain_positive(DnsTrustAnchor *d, const char *name) {
  29         assert(d);
  30
  31         /* Returns true if there's an entry for the specified domain
  32          * name in our trust anchor */
  33
  34         return
  35                 hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_DNSKEY, name)) ||
  36                 hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_DS, name));
  37 }
  38
  39 static int add_root_ksk(
  40                 DnsAnswer *answer,
  41                 DnsResourceKey *key,
  42                 uint16_t key_tag,
  43                 uint8_t algorithm,
  44                 uint8_t digest_type,
  45                 const void *digest,
  46                 size_t digest_size) {
  47
  48         _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
  49         int r;
  50
  51         rr = dns_resource_record_new(key);
  52         if (!rr)
  53                 return -ENOMEM;
  54
  55         rr->ds.key_tag = key_tag;
  56         rr->ds.algorithm = algorithm;
  57         rr->ds.digest_type = digest_type;
  58         rr->ds.digest_size = digest_size;
  59         rr->ds.digest = memdup(digest, rr->ds.digest_size);
  60         if (!rr->ds.digest)
  61                 return  -ENOMEM;
  62
  63         r = dns_answer_add(answer, rr, 0, DNS_ANSWER_AUTHENTICATED, NULL);
  64         if (r < 0)
  65                 return r;
  66
  67         return 0;
  68 }
  69
  70 static int dns_trust_anchor_add_builtin_positive(DnsTrustAnchor *d) {
  71         _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
  72         _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
  73         int r;
  74
  75         assert(d);
  76
  77         r = hashmap_ensure_allocated(&d->positive_by_key, &dns_resource_key_hash_ops);
  78         if (r < 0)
  79                 return r;
  80
  81         /* Only add the built-in trust anchor if there's neither a DS nor a DNSKEY defined for the root domain. That
  82          * way users have an easy way to override the root domain DS/DNSKEY data. */
  83         if (dns_trust_anchor_knows_domain_positive(d, "."))
  84                 return 0;
  85
  86         key = dns_resource_key_new(DNS_CLASS_IN, DNS_TYPE_DS, "");
  87         if (!key)
  88                 return -ENOMEM;
  89
  90         answer = dns_answer_new(2);
  91         if (!answer)
  92                 return -ENOMEM;
  93
  94         /* Add the currently valid RRs from https://data.iana.org/root-anchors/root-anchors.xml */
  95         r = add_root_ksk(answer, key, 20326, DNSSEC_ALGORITHM_RSASHA256, DNSSEC_DIGEST_SHA256, root_digest2, sizeof(root_digest2));
  96         if (r < 0)
  97                 return r;
  98
  99         r = hashmap_put(d->positive_by_key, key, answer);
 100         if (r < 0)
 101                 return r;
 102
 103         answer = NULL;
 104         return 0;
 105 }
 106
 107 static int dns_trust_anchor_add_builtin_negative(DnsTrustAnchor *d) {
 108
 109         static const char private_domains[] =
 110                 /* RFC 6761 says that .test is a special domain for
 111                  * testing and not to be installed in the root zone */
 112                 "test\0"
 113
 114                 /* RFC 6761 says that these reverse IP lookup ranges
 115                  * are for private addresses, and hence should not
 116                  * show up in the root zone */
 117                 "10.in-addr.arpa\0"
 118                 "16.172.in-addr.arpa\0"
 119                 "17.172.in-addr.arpa\0"
 120                 "18.172.in-addr.arpa\0"
 121                 "19.172.in-addr.arpa\0"
 122                 "20.172.in-addr.arpa\0"
 123                 "21.172.in-addr.arpa\0"
 124                 "22.172.in-addr.arpa\0"
 125                 "23.172.in-addr.arpa\0"
 126                 "24.172.in-addr.arpa\0"
 127                 "25.172.in-addr.arpa\0"
 128                 "26.172.in-addr.arpa\0"
 129                 "27.172.in-addr.arpa\0"
 130                 "28.172.in-addr.arpa\0"
 131                 "29.172.in-addr.arpa\0"
 132                 "30.172.in-addr.arpa\0"
 133                 "31.172.in-addr.arpa\0"
 134                 "168.192.in-addr.arpa\0"
 135
 136                 /* The same, but for IPv6. */
 137                 "d.f.ip6.arpa\0"
 138
 139                 /* RFC 6762 reserves the .local domain for Multicast
 140                  * DNS, it hence cannot appear in the root zone. (Note
 141                  * that we by default do not route .local traffic to
 142                  * DNS anyway, except when a configured search domain
 143                  * suggests so.) */
 144                 "local\0"
 145
 146                 /* These two are well known, popular private zone
 147                  * TLDs, that are blocked from delegation, according
 148                  * to:
 149                  * http://icannwiki.com/Name_Collision#NGPC_Resolution
 150                  *
 151                  * There's also ongoing work on making this official
 152                  * in an RRC:
 153                  * https://www.ietf.org/archive/id/draft-chapin-additional-reserved-tlds-02.txt */
 154                 "home\0"
 155                 "corp\0"
 156
 157                 /* The following four TLDs are suggested for private
 158                  * zones in RFC 6762, Appendix G, and are hence very
 159                  * unlikely to be made official TLDs any day soon */
 160                 "lan\0"
 161                 "intranet\0"
 162                 "internal\0"
 163                 "private\0"
 164
 165                 /* Defined by RFC 8375. The most official choice. */
 166                 "home.arpa\0";
 167
 168         const char *name;
 169         int r;
 170
 171         assert(d);
 172
 173         /* Only add the built-in trust anchor if there's no negative
 174          * trust anchor defined at all. This enables easy overriding
 175          * of negative trust anchors. */
 176
 177         if (set_size(d->negative_by_name) > 0)
 178                 return 0;
 179
 180         r = set_ensure_allocated(&d->negative_by_name, &dns_name_hash_ops);
 181         if (r < 0)
 182                 return r;
 183
 184         /* We add a couple of domains as default negative trust
 185          * anchors, where it's very unlikely they will be installed in
 186          * the root zone. If they exist they must be private, and thus
 187          * unsigned. */
 188
 189         NULSTR_FOREACH(name, private_domains) {
 190                 if (dns_trust_anchor_knows_domain_positive(d, name))
 191                         continue;
 192
 193                 r = set_put_strdup(&d->negative_by_name, name);
 194                 if (r < 0)
 195                         return r;
 196         }
 197
 198         return 0;
 199 }
 200
 201 static int dns_trust_anchor_load_positive(DnsTrustAnchor *d, const char *path, unsigned line, const char *s) {
 202         _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
 203         _cleanup_free_ char *domain = NULL, *class = NULL, *type = NULL;
 204         _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
 205         DnsAnswer *old_answer = NULL;
 206         const char *p = s;
 207         int r;
 208
 209         assert(d);
 210         assert(line);
 211
 212         r = extract_first_word(&p, &domain, NULL, EXTRACT_UNQUOTE);
 213         if (r < 0)
 214                 return log_warning_errno(r, "Unable to parse domain in line %s:%u: %m", path, line);
 215
 216         r = dns_name_is_valid(domain);
 217         if (r < 0)
 218                 return log_warning_errno(r, "Failed to check validity of domain name '%s', at line %s:%u, ignoring line: %m", domain, path, line);
 219         if (r == 0) {
 220                 log_warning("Domain name %s is invalid, at line %s:%u, ignoring line.", domain, path, line);
 221                 return -EINVAL;
 222         }
 223
 224         r = extract_many_words(&p, NULL, 0, &class, &type, NULL);
 225         if (r < 0)
 226                 return log_warning_errno(r, "Unable to parse class and type in line %s:%u: %m", path, line);
 227         if (r != 2) {
 228                 log_warning("Missing class or type in line %s:%u", path, line);
 229                 return -EINVAL;
 230         }
 231
 232         if (!strcaseeq(class, "IN")) {
 233                 log_warning("RR class %s is not supported, ignoring line %s:%u.", class, path, line);
 234                 return -EINVAL;
 235         }
 236
 237         if (strcaseeq(type, "DS")) {
 238                 _cleanup_free_ char *key_tag = NULL, *algorithm = NULL, *digest_type = NULL;
 239                 _cleanup_free_ void *dd = NULL;
 240                 uint16_t kt;
 241                 int a, dt;
 242                 size_t l;
 243
 244                 r = extract_many_words(&p, NULL, 0, &key_tag, &algorithm, &digest_type, NULL);
 245                 if (r < 0) {
 246                         log_warning_errno(r, "Failed to parse DS parameters on line %s:%u: %m", path, line);
 247                         return -EINVAL;
 248                 }
 249                 if (r != 3) {
 250                         log_warning("Missing DS parameters on line %s:%u", path, line);
 251                         return -EINVAL;
 252                 }
 253
 254                 r = safe_atou16(key_tag, &kt);
 255                 if (r < 0)
 256                         return log_warning_errno(r, "Failed to parse DS key tag %s on line %s:%u: %m", key_tag, path, line);
 257
 258                 a = dnssec_algorithm_from_string(algorithm);
 259                 if (a < 0) {
 260                         log_warning("Failed to parse DS algorithm %s on line %s:%u", algorithm, path, line);
 261                         return -EINVAL;
 262                 }
 263
 264                 dt = dnssec_digest_from_string(digest_type);
 265                 if (dt < 0) {
 266                         log_warning("Failed to parse DS digest type %s on line %s:%u", digest_type, path, line);
 267                         return -EINVAL;
 268                 }
 269
 270                 if (isempty(p)) {
 271                         log_warning("Missing DS digest on line %s:%u", path, line);
 272                         return -EINVAL;
 273                 }
 274
 275                 r = unhexmem(p, strlen(p), &dd, &l);
 276                 if (r < 0) {
 277                         log_warning("Failed to parse DS digest %s on line %s:%u", p, path, line);
 278                         return -EINVAL;
 279                 }
 280
 281                 rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_DS, domain);
 282                 if (!rr)
 283                         return log_oom();
 284
 285                 rr->ds.key_tag = kt;
 286                 rr->ds.algorithm = a;
 287                 rr->ds.digest_type = dt;
 288                 rr->ds.digest_size = l;
 289                 rr->ds.digest = TAKE_PTR(dd);
 290
 291         } else if (strcaseeq(type, "DNSKEY")) {
 292                 _cleanup_free_ char *flags = NULL, *protocol = NULL, *algorithm = NULL;
 293                 _cleanup_free_ void *k = NULL;
 294                 uint16_t f;
 295                 size_t l;
 296                 int a;
 297
 298                 r = extract_many_words(&p, NULL, 0, &flags, &protocol, &algorithm, NULL);
 299                 if (r < 0)
 300                         return log_warning_errno(r, "Failed to parse DNSKEY parameters on line %s:%u: %m", path, line);
 301                 if (r != 3) {
 302                         log_warning("Missing DNSKEY parameters on line %s:%u", path, line);
 303                         return -EINVAL;
 304                 }
 305
 306                 if (!streq(protocol, "3")) {
 307                         log_warning("DNSKEY Protocol is not 3 on line %s:%u", path, line);
 308                         return -EINVAL;
 309                 }
 310
 311                 r = safe_atou16(flags, &f);
 312                 if (r < 0)
 313                         return log_warning_errno(r, "Failed to parse DNSKEY flags field %s on line %s:%u", flags, path, line);
 314                 if ((f & DNSKEY_FLAG_ZONE_KEY) == 0) {
 315                         log_warning("DNSKEY lacks zone key bit set on line %s:%u", path, line);
 316                         return -EINVAL;
 317                 }
 318                 if ((f & DNSKEY_FLAG_REVOKE)) {
 319                         log_warning("DNSKEY is already revoked on line %s:%u", path, line);
 320                         return -EINVAL;
 321                 }
 322
 323                 a = dnssec_algorithm_from_string(algorithm);
 324                 if (a < 0) {
 325                         log_warning("Failed to parse DNSKEY algorithm %s on line %s:%u", algorithm, path, line);
 326                         return -EINVAL;
 327                 }
 328
 329                 if (isempty(p)) {
 330                         log_warning("Missing DNSKEY key on line %s:%u", path, line);
 331                         return -EINVAL;
 332                 }
 333
 334                 r = unbase64mem(p, strlen(p), &k, &l);
 335                 if (r < 0)
 336                         return log_warning_errno(r, "Failed to parse DNSKEY key data %s on line %s:%u", p, path, line);
 337
 338                 rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_DNSKEY, domain);
 339                 if (!rr)
 340                         return log_oom();
 341
 342                 rr->dnskey.flags = f;
 343                 rr->dnskey.protocol = 3;
 344                 rr->dnskey.algorithm = a;
 345                 rr->dnskey.key_size = l;
 346                 rr->dnskey.key = TAKE_PTR(k);
 347
 348         } else {
 349                 log_warning("RR type %s is not supported, ignoring line %s:%u.", type, path, line);
 350                 return -EINVAL;
 351         }
 352
 353         r = hashmap_ensure_allocated(&d->positive_by_key, &dns_resource_key_hash_ops);
 354         if (r < 0)
 355                 return log_oom();
 356
 357         old_answer = hashmap_get(d->positive_by_key, rr->key);
 358         answer = dns_answer_ref(old_answer);
 359
 360         r = dns_answer_add_extend(&answer, rr, 0, DNS_ANSWER_AUTHENTICATED, NULL);
 361         if (r < 0)
 362                 return log_error_errno(r, "Failed to add trust anchor RR: %m");
 363
 364         r = hashmap_replace(d->positive_by_key, rr->key, answer);
 365         if (r < 0)
 366                 return log_error_errno(r, "Failed to add answer to trust anchor: %m");
 367
 368         old_answer = dns_answer_unref(old_answer);
 369         answer = NULL;
 370
 371         return 0;
 372 }
 373
 374 static int dns_trust_anchor_load_negative(DnsTrustAnchor *d, const char *path, unsigned line, const char *s) {
 375         _cleanup_free_ char *domain = NULL;
 376         const char *p = s;
 377         int r;
 378
 379         assert(d);
 380         assert(line);
 381
 382         r = extract_first_word(&p, &domain, NULL, EXTRACT_UNQUOTE);
 383         if (r < 0)
 384                 return log_warning_errno(r, "Unable to parse line %s:%u: %m", path, line);
 385
 386         r = dns_name_is_valid(domain);
 387         if (r < 0)
 388                 return log_warning_errno(r, "Failed to check validity of domain name '%s', at line %s:%u, ignoring line: %m", domain, path, line);
 389         if (r == 0) {
 390                 log_warning("Domain name %s is invalid, at line %s:%u, ignoring line.", domain, path, line);
 391                 return -EINVAL;
 392         }
 393
 394         if (!isempty(p)) {
 395                 log_warning("Trailing garbage at line %s:%u, ignoring line.", path, line);
 396                 return -EINVAL;
 397         }
 398
 399         r = set_ensure_consume(&d->negative_by_name, &dns_name_hash_ops, TAKE_PTR(domain));
 400         if (r < 0)
 401                 return log_oom();
 402
 403         return 0;
 404 }
 405
 406 static int dns_trust_anchor_load_files(
 407                 DnsTrustAnchor *d,
 408                 const char *suffix,
 409                 int (*loader)(DnsTrustAnchor *d, const char *path, unsigned n, const char *line)) {
 410
 411         _cleanup_strv_free_ char **files = NULL;
 412         char **f;
 413         int r;
 414
 415         assert(d);
 416         assert(suffix);
 417         assert(loader);
 418
 419         r = conf_files_list_nulstr(&files, suffix, NULL, 0, trust_anchor_dirs);
 420         if (r < 0)
 421                 return log_error_errno(r, "Failed to enumerate %s trust anchor files: %m", suffix);
 422
 423         STRV_FOREACH(f, files) {
 424                 _cleanup_fclose_ FILE *g = NULL;
 425                 unsigned n = 0;
 426
 427                 g = fopen(*f, "r");
 428                 if (!g) {
 429                         if (errno == ENOENT)
 430                                 continue;
 431
 432                         log_warning_errno(errno, "Failed to open '%s', ignoring: %m", *f);
 433                         continue;
 434                 }
 435
 436                 for (;;) {
 437                         _cleanup_free_ char *line = NULL;
 438                         char *l;
 439
 440                         r = read_line(g, LONG_LINE_MAX, &line);
 441                         if (r < 0) {
 442                                 log_warning_errno(r, "Failed to read '%s', ignoring: %m", *f);
 443                                 break;
 444                         }
 445                         if (r == 0)
 446                                 break;
 447
 448                         n++;
 449
 450                         l = strstrip(line);
 451                         if (isempty(l))
 452                                 continue;
 453
 454                         if (*l == ';')
 455                                 continue;
 456
 457                         (void) loader(d, *f, n, l);
 458                 }
 459         }
 460
 461         return 0;
 462 }
 463
 464 static int domain_name_cmp(char * const *a, char * const *b) {
 465         return dns_name_compare_func(*a, *b);
 466 }
 467
 468 static int dns_trust_anchor_dump(DnsTrustAnchor *d) {
 469         DnsAnswer *a;
 470
 471         assert(d);
 472
 473         if (hashmap_isempty(d->positive_by_key))
 474                 log_info("No positive trust anchors defined.");
 475         else {
 476                 log_info("Positive Trust Anchors:");
 477                 HASHMAP_FOREACH(a, d->positive_by_key) {
 478                         DnsResourceRecord *rr;
 479
 480                         DNS_ANSWER_FOREACH(rr, a)
 481                                 log_info("%s", dns_resource_record_to_string(rr));
 482                 }
 483         }
 484
 485         if (set_isempty(d->negative_by_name))
 486                 log_info("No negative trust anchors defined.");
 487         else {
 488                 _cleanup_free_ char **l = NULL, *j = NULL;
 489
 490                 l = set_get_strv(d->negative_by_name);
 491                 if (!l)
 492                         return log_oom();
 493
 494                 typesafe_qsort(l, set_size(d->negative_by_name), domain_name_cmp);
 495
 496                 j = strv_join(l, " ");
 497                 if (!j)
 498                         return log_oom();
 499
 500                 log_info("Negative trust anchors: %s", j);
 501         }
 502
 503         return 0;
 504 }
 505
 506 int dns_trust_anchor_load(DnsTrustAnchor *d) {
 507         int r;
 508
 509         assert(d);
 510
 511         /* If loading things from disk fails, we don't consider this fatal */
 512         (void) dns_trust_anchor_load_files(d, ".positive", dns_trust_anchor_load_positive);
 513         (void) dns_trust_anchor_load_files(d, ".negative", dns_trust_anchor_load_negative);
 514
 515         /* However, if the built-in DS fails, then we have a problem. */
 516         r = dns_trust_anchor_add_builtin_positive(d);
 517         if (r < 0)
 518                 return log_error_errno(r, "Failed to add built-in positive trust anchor: %m");
 519
 520         r = dns_trust_anchor_add_builtin_negative(d);
 521         if (r < 0)
 522                 return log_error_errno(r, "Failed to add built-in negative trust anchor: %m");
 523
 524         dns_trust_anchor_dump(d);
 525
 526         return 0;
 527 }
 528
 529 void dns_trust_anchor_flush(DnsTrustAnchor *d) {
 530         assert(d);
 531
 532         d->positive_by_key = hashmap_free_with_destructor(d->positive_by_key, dns_answer_unref);
 533         d->revoked_by_rr = set_free_with_destructor(d->revoked_by_rr, dns_resource_record_unref);
 534         d->negative_by_name = set_free_free(d->negative_by_name);
 535 }
 536
 537 int dns_trust_anchor_lookup_positive(DnsTrustAnchor *d, const DnsResourceKey *key, DnsAnswer **ret) {
 538         DnsAnswer *a;
 539
 540         assert(d);
 541         assert(key);
 542         assert(ret);
 543
 544         /* We only serve DS and DNSKEY RRs. */
 545         if (!IN_SET(key->type, DNS_TYPE_DS, DNS_TYPE_DNSKEY))
 546                 return 0;
 547
 548         a = hashmap_get(d->positive_by_key, key);
 549         if (!a)
 550                 return 0;
 551
 552         *ret = dns_answer_ref(a);
 553         return 1;
 554 }
 555
 556 int dns_trust_anchor_lookup_negative(DnsTrustAnchor *d, const char *name) {
 557         int r;
 558
 559         assert(d);
 560         assert(name);
 561
 562         for (;;) {
 563                 /* If the domain is listed as-is in the NTA database, then that counts */
 564                 if (set_contains(d->negative_by_name, name))
 565                         return true;
 566
 567                 /* If the domain isn't listed as NTA, but is listed as positive trust anchor, then that counts. See RFC
 568                  * 7646, section 1.1 */
 569                 if (hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_DS, name)))
 570                         return false;
 571
 572                 if (hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_KEY, name)))
 573                         return false;
 574
 575                 /* And now, let's look at the parent, and check that too */
 576                 r = dns_name_parent(&name);
 577                 if (r < 0)
 578                         return r;
 579                 if (r == 0)
 580                         break;
 581         }
 582
 583         return false;
 584 }
 585
 586 static int dns_trust_anchor_revoked_put(DnsTrustAnchor *d, DnsResourceRecord *rr) {
 587         int r;
 588
 589         assert(d);
 590
 591         r = set_ensure_put(&d->revoked_by_rr, &dns_resource_record_hash_ops, rr);
 592         if (r < 0)
 593                 return r;
 594         if (r > 0)
 595                 dns_resource_record_ref(rr);
 596
 597         return r;
 598 }
 599
 600 static int dns_trust_anchor_remove_revoked(DnsTrustAnchor *d, DnsResourceRecord *rr) {
 601         _cleanup_(dns_answer_unrefp) DnsAnswer *new_answer = NULL;
 602         DnsAnswer *old_answer;
 603         int r;
 604
 605         /* Remember that this is a revoked trust anchor RR */
 606         r = dns_trust_anchor_revoked_put(d, rr);
 607         if (r < 0)
 608                 return r;
 609
 610         /* Remove this from the positive trust anchor */
 611         old_answer = hashmap_get(d->positive_by_key, rr->key);
 612         if (!old_answer)
 613                 return 0;
 614
 615         new_answer = dns_answer_ref(old_answer);
 616
 617         r = dns_answer_remove_by_rr(&new_answer, rr);
 618         if (r <= 0)
 619                 return r;
 620
 621         /* We found the key! Warn the user */
 622         log_struct(LOG_WARNING,
 623                    "MESSAGE_ID=" SD_MESSAGE_DNSSEC_TRUST_ANCHOR_REVOKED_STR,
 624                    LOG_MESSAGE("DNSSEC trust anchor %s has been revoked.\n"
 625                                "Please update the trust anchor, or upgrade your operating system.",
 626                                strna(dns_resource_record_to_string(rr))),
 627                    "TRUST_ANCHOR=%s", dns_resource_record_to_string(rr));
 628
 629         if (dns_answer_size(new_answer) <= 0) {
 630                 assert_se(hashmap_remove(d->positive_by_key, rr->key) == old_answer);
 631                 dns_answer_unref(old_answer);
 632                 return 1;
 633         }
 634
 635         r = hashmap_replace(d->positive_by_key, new_answer->items[0].rr->key, new_answer);
 636         if (r < 0)
 637                 return r;
 638
 639         new_answer = NULL;
 640         dns_answer_unref(old_answer);
 641         return 1;
 642 }
 643
 644 static int dns_trust_anchor_check_revoked_one(DnsTrustAnchor *d, DnsResourceRecord *revoked_dnskey) {
 645         DnsAnswer *a;
 646         int r;
 647
 648         assert(d);
 649         assert(revoked_dnskey);
 650         assert(revoked_dnskey->key->type == DNS_TYPE_DNSKEY);
 651         assert(revoked_dnskey->dnskey.flags & DNSKEY_FLAG_REVOKE);
 652
 653         a = hashmap_get(d->positive_by_key, revoked_dnskey->key);
 654         if (a) {
 655                 DnsResourceRecord *anchor;
 656
 657                 /* First, look for the precise DNSKEY in our trust anchor database */
 658
 659                 DNS_ANSWER_FOREACH(anchor, a) {
 660
 661                         if (anchor->dnskey.protocol != revoked_dnskey->dnskey.protocol)
 662                                 continue;
 663
 664                         if (anchor->dnskey.algorithm != revoked_dnskey->dnskey.algorithm)
 665                                 continue;
 666
 667                         if (anchor->dnskey.key_size != revoked_dnskey->dnskey.key_size)
 668                                 continue;
 669
 670                         /* Note that we allow the REVOKE bit to be
 671                          * different! It will be set in the revoked
 672                          * key, but unset in our version of it */
 673                         if (((anchor->dnskey.flags ^ revoked_dnskey->dnskey.flags) | DNSKEY_FLAG_REVOKE) != DNSKEY_FLAG_REVOKE)
 674                                 continue;
 675
 676                         if (memcmp(anchor->dnskey.key, revoked_dnskey->dnskey.key, anchor->dnskey.key_size) != 0)
 677                                 continue;
 678
 679                         dns_trust_anchor_remove_revoked(d, anchor);
 680                         break;
 681                 }
 682         }
 683
 684         a = hashmap_get(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(revoked_dnskey->key->class, DNS_TYPE_DS, dns_resource_key_name(revoked_dnskey->key)));
 685         if (a) {
 686                 DnsResourceRecord *anchor;
 687
 688                 /* Second, look for DS RRs matching this DNSKEY in our trust anchor database */
 689
 690                 DNS_ANSWER_FOREACH(anchor, a) {
 691
 692                         /* We set mask_revoke to true here, since our
 693                          * DS fingerprint will be the one of the
 694                          * unrevoked DNSKEY, but the one we got passed
 695                          * here has the bit set. */
 696                         r = dnssec_verify_dnskey_by_ds(revoked_dnskey, anchor, true);
 697                         if (r < 0)
 698                                 return r;
 699                         if (r == 0)
 700                                 continue;
 701
 702                         dns_trust_anchor_remove_revoked(d, anchor);
 703                         break;
 704                 }
 705         }
 706
 707         return 0;
 708 }
 709
 710 int dns_trust_anchor_check_revoked(DnsTrustAnchor *d, DnsResourceRecord *dnskey, DnsAnswer *rrs) {
 711         DnsResourceRecord *rrsig;
 712         int r;
 713
 714         assert(d);
 715         assert(dnskey);
 716
 717         /* Looks if "dnskey" is a self-signed RR that has been revoked
 718          * and matches one of our trust anchor entries. If so, removes
 719          * it from the trust anchor and returns > 0. */
 720
 721         if (dnskey->key->type != DNS_TYPE_DNSKEY)
 722                 return 0;
 723
 724         /* Is this DNSKEY revoked? */
 725         if ((dnskey->dnskey.flags & DNSKEY_FLAG_REVOKE) == 0)
 726                 return 0;
 727
 728         /* Could this be interesting to us at all? If not,
 729          * there's no point in looking for and verifying a
 730          * self-signed RRSIG. */
 731         if (!dns_trust_anchor_knows_domain_positive(d, dns_resource_key_name(dnskey->key)))
 732                 return 0;
 733
 734         /* Look for a self-signed RRSIG in the other rrs belonging to this DNSKEY */
 735         DNS_ANSWER_FOREACH(rrsig, rrs) {
 736                 DnssecResult result;
 737
 738                 if (rrsig->key->type != DNS_TYPE_RRSIG)
 739                         continue;
 740
 741                 r = dnssec_rrsig_match_dnskey(rrsig, dnskey, true);
 742                 if (r < 0)
 743                         return r;
 744                 if (r == 0)
 745                         continue;
 746
 747                 r = dnssec_verify_rrset(rrs, dnskey->key, rrsig, dnskey, USEC_INFINITY, &result);
 748                 if (r < 0)
 749                         return r;
 750                 if (result != DNSSEC_VALIDATED)
 751                         continue;
 752
 753                 /* Bingo! This is a revoked self-signed DNSKEY. Let's
 754                  * see if this precise one exists in our trust anchor
 755                  * database, too. */
 756                 r = dns_trust_anchor_check_revoked_one(d, dnskey);
 757                 if (r < 0)
 758                         return r;
 759
 760                 return 1;
 761         }
 762
 763         return 0;
 764 }
 765
 766 int dns_trust_anchor_is_revoked(DnsTrustAnchor *d, DnsResourceRecord *rr) {
 767         assert(d);
 768
 769         if (!IN_SET(rr->key->type, DNS_TYPE_DS, DNS_TYPE_DNSKEY))
 770                 return 0;
 771
 772         return set_contains(d->revoked_by_rr, rr);
 773 }