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 "constants.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                 /* RFC 8880 says because the 'ipv4only.arpa' zone has to
 169                  * be an insecure delegation, DNSSEC cannot be used to
 170                  * protect these answers from tampering by malicious
 171                  * devices on the path */
 172                 "ipv4only.arpa\0"
 173                 "170.0.0.192.in-addr.arpa\0"
 174                 "171.0.0.192.in-addr.arpa\0";
 175
 176         int r;
 177
 178         assert(d);
 179
 180         /* Only add the built-in trust anchor if there's no negative
 181          * trust anchor defined at all. This enables easy overriding
 182          * of negative trust anchors. */
 183
 184         if (!set_isempty(d->negative_by_name))
 185                 return 0;
 186
 187         r = set_ensure_allocated(&d->negative_by_name, &dns_name_hash_ops);
 188         if (r < 0)
 189                 return r;
 190
 191         /* We add a couple of domains as default negative trust
 192          * anchors, where it's very unlikely they will be installed in
 193          * the root zone. If they exist they must be private, and thus
 194          * unsigned. */
 195
 196         NULSTR_FOREACH(name, private_domains) {
 197                 if (dns_trust_anchor_knows_domain_positive(d, name))
 198                         continue;
 199
 200                 r = set_put_strdup(&d->negative_by_name, name);
 201                 if (r < 0)
 202                         return r;
 203         }
 204
 205         return 0;
 206 }
 207
 208 static int dns_trust_anchor_load_positive(DnsTrustAnchor *d, const char *path, unsigned line, const char *s) {
 209         _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
 210         _cleanup_free_ char *domain = NULL, *class = NULL, *type = NULL;
 211         _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
 212         DnsAnswer *old_answer = NULL;
 213         const char *p = s;
 214         int r;
 215
 216         assert(d);
 217         assert(line);
 218
 219         r = extract_first_word(&p, &domain, NULL, EXTRACT_UNQUOTE);
 220         if (r < 0)
 221                 return log_warning_errno(r, "Unable to parse domain in line %s:%u: %m", path, line);
 222
 223         r = dns_name_is_valid(domain);
 224         if (r < 0)
 225                 return log_warning_errno(r, "Failed to check validity of domain name '%s', at line %s:%u, ignoring line: %m", domain, path, line);
 226         if (r == 0) {
 227                 log_warning("Domain name %s is invalid, at line %s:%u, ignoring line.", domain, path, line);
 228                 return -EINVAL;
 229         }
 230
 231         r = extract_many_words(&p, NULL, 0, &class, &type, NULL);
 232         if (r < 0)
 233                 return log_warning_errno(r, "Unable to parse class and type in line %s:%u: %m", path, line);
 234         if (r != 2) {
 235                 log_warning("Missing class or type in line %s:%u", path, line);
 236                 return -EINVAL;
 237         }
 238
 239         if (!strcaseeq(class, "IN")) {
 240                 log_warning("RR class %s is not supported, ignoring line %s:%u.", class, path, line);
 241                 return -EINVAL;
 242         }
 243
 244         if (strcaseeq(type, "DS")) {
 245                 _cleanup_free_ char *key_tag = NULL, *algorithm = NULL, *digest_type = NULL;
 246                 _cleanup_free_ void *dd = NULL;
 247                 uint16_t kt;
 248                 int a, dt;
 249                 size_t l;
 250
 251                 r = extract_many_words(&p, NULL, 0, &key_tag, &algorithm, &digest_type, NULL);
 252                 if (r < 0) {
 253                         log_warning_errno(r, "Failed to parse DS parameters on line %s:%u: %m", path, line);
 254                         return -EINVAL;
 255                 }
 256                 if (r != 3) {
 257                         log_warning("Missing DS parameters on line %s:%u", path, line);
 258                         return -EINVAL;
 259                 }
 260
 261                 r = safe_atou16(key_tag, &kt);
 262                 if (r < 0)
 263                         return log_warning_errno(r, "Failed to parse DS key tag %s on line %s:%u: %m", key_tag, path, line);
 264
 265                 a = dnssec_algorithm_from_string(algorithm);
 266                 if (a < 0) {
 267                         log_warning("Failed to parse DS algorithm %s on line %s:%u", algorithm, path, line);
 268                         return -EINVAL;
 269                 }
 270
 271                 dt = dnssec_digest_from_string(digest_type);
 272                 if (dt < 0) {
 273                         log_warning("Failed to parse DS digest type %s on line %s:%u", digest_type, path, line);
 274                         return -EINVAL;
 275                 }
 276
 277                 if (isempty(p)) {
 278                         log_warning("Missing DS digest on line %s:%u", path, line);
 279                         return -EINVAL;
 280                 }
 281
 282                 r = unhexmem(p, strlen(p), &dd, &l);
 283                 if (r < 0) {
 284                         log_warning("Failed to parse DS digest %s on line %s:%u", p, path, line);
 285                         return -EINVAL;
 286                 }
 287
 288                 rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_DS, domain);
 289                 if (!rr)
 290                         return log_oom();
 291
 292                 rr->ds.key_tag = kt;
 293                 rr->ds.algorithm = a;
 294                 rr->ds.digest_type = dt;
 295                 rr->ds.digest_size = l;
 296                 rr->ds.digest = TAKE_PTR(dd);
 297
 298         } else if (strcaseeq(type, "DNSKEY")) {
 299                 _cleanup_free_ char *flags = NULL, *protocol = NULL, *algorithm = NULL;
 300                 _cleanup_free_ void *k = NULL;
 301                 uint16_t f;
 302                 size_t l;
 303                 int a;
 304
 305                 r = extract_many_words(&p, NULL, 0, &flags, &protocol, &algorithm, NULL);
 306                 if (r < 0)
 307                         return log_warning_errno(r, "Failed to parse DNSKEY parameters on line %s:%u: %m", path, line);
 308                 if (r != 3) {
 309                         log_warning("Missing DNSKEY parameters on line %s:%u", path, line);
 310                         return -EINVAL;
 311                 }
 312
 313                 if (!streq(protocol, "3")) {
 314                         log_warning("DNSKEY Protocol is not 3 on line %s:%u", path, line);
 315                         return -EINVAL;
 316                 }
 317
 318                 r = safe_atou16(flags, &f);
 319                 if (r < 0)
 320                         return log_warning_errno(r, "Failed to parse DNSKEY flags field %s on line %s:%u", flags, path, line);
 321                 if ((f & DNSKEY_FLAG_ZONE_KEY) == 0) {
 322                         log_warning("DNSKEY lacks zone key bit set on line %s:%u", path, line);
 323                         return -EINVAL;
 324                 }
 325                 if ((f & DNSKEY_FLAG_REVOKE)) {
 326                         log_warning("DNSKEY is already revoked on line %s:%u", path, line);
 327                         return -EINVAL;
 328                 }
 329
 330                 a = dnssec_algorithm_from_string(algorithm);
 331                 if (a < 0) {
 332                         log_warning("Failed to parse DNSKEY algorithm %s on line %s:%u", algorithm, path, line);
 333                         return -EINVAL;
 334                 }
 335
 336                 if (isempty(p)) {
 337                         log_warning("Missing DNSKEY key on line %s:%u", path, line);
 338                         return -EINVAL;
 339                 }
 340
 341                 r = unbase64mem(p, strlen(p), &k, &l);
 342                 if (r < 0)
 343                         return log_warning_errno(r, "Failed to parse DNSKEY key data %s on line %s:%u", p, path, line);
 344
 345                 rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_DNSKEY, domain);
 346                 if (!rr)
 347                         return log_oom();
 348
 349                 rr->dnskey.flags = f;
 350                 rr->dnskey.protocol = 3;
 351                 rr->dnskey.algorithm = a;
 352                 rr->dnskey.key_size = l;
 353                 rr->dnskey.key = TAKE_PTR(k);
 354
 355         } else {
 356                 log_warning("RR type %s is not supported, ignoring line %s:%u.", type, path, line);
 357                 return -EINVAL;
 358         }
 359
 360         r = hashmap_ensure_allocated(&d->positive_by_key, &dns_resource_key_hash_ops);
 361         if (r < 0)
 362                 return log_oom();
 363
 364         old_answer = hashmap_get(d->positive_by_key, rr->key);
 365         answer = dns_answer_ref(old_answer);
 366
 367         r = dns_answer_add_extend(&answer, rr, 0, DNS_ANSWER_AUTHENTICATED, NULL);
 368         if (r < 0)
 369                 return log_error_errno(r, "Failed to add trust anchor RR: %m");
 370
 371         r = hashmap_replace(d->positive_by_key, rr->key, answer);
 372         if (r < 0)
 373                 return log_error_errno(r, "Failed to add answer to trust anchor: %m");
 374
 375         old_answer = dns_answer_unref(old_answer);
 376         answer = NULL;
 377
 378         return 0;
 379 }
 380
 381 static int dns_trust_anchor_load_negative(DnsTrustAnchor *d, const char *path, unsigned line, const char *s) {
 382         _cleanup_free_ char *domain = NULL;
 383         const char *p = s;
 384         int r;
 385
 386         assert(d);
 387         assert(line);
 388
 389         r = extract_first_word(&p, &domain, NULL, EXTRACT_UNQUOTE);
 390         if (r < 0)
 391                 return log_warning_errno(r, "Unable to parse line %s:%u: %m", path, line);
 392
 393         r = dns_name_is_valid(domain);
 394         if (r < 0)
 395                 return log_warning_errno(r, "Failed to check validity of domain name '%s', at line %s:%u, ignoring line: %m", domain, path, line);
 396         if (r == 0) {
 397                 log_warning("Domain name %s is invalid, at line %s:%u, ignoring line.", domain, path, line);
 398                 return -EINVAL;
 399         }
 400
 401         if (!isempty(p)) {
 402                 log_warning("Trailing garbage at line %s:%u, ignoring line.", path, line);
 403                 return -EINVAL;
 404         }
 405
 406         r = set_ensure_consume(&d->negative_by_name, &dns_name_hash_ops, TAKE_PTR(domain));
 407         if (r < 0)
 408                 return log_oom();
 409
 410         return 0;
 411 }
 412
 413 static int dns_trust_anchor_load_files(
 414                 DnsTrustAnchor *d,
 415                 const char *suffix,
 416                 int (*loader)(DnsTrustAnchor *d, const char *path, unsigned n, const char *line)) {
 417
 418         _cleanup_strv_free_ char **files = NULL;
 419         int r;
 420
 421         assert(d);
 422         assert(suffix);
 423         assert(loader);
 424
 425         r = conf_files_list_nulstr(&files, suffix, NULL, 0, trust_anchor_dirs);
 426         if (r < 0)
 427                 return log_error_errno(r, "Failed to enumerate %s trust anchor files: %m", suffix);
 428
 429         STRV_FOREACH(f, files) {
 430                 _cleanup_fclose_ FILE *g = NULL;
 431                 unsigned n = 0;
 432
 433                 g = fopen(*f, "re");
 434                 if (!g) {
 435                         if (errno == ENOENT)
 436                                 continue;
 437
 438                         log_warning_errno(errno, "Failed to open '%s', ignoring: %m", *f);
 439                         continue;
 440                 }
 441
 442                 for (;;) {
 443                         _cleanup_free_ char *line = NULL;
 444
 445                         r = read_stripped_line(g, LONG_LINE_MAX, &line);
 446                         if (r < 0) {
 447                                 log_warning_errno(r, "Failed to read '%s', ignoring: %m", *f);
 448                                 break;
 449                         }
 450                         if (r == 0)
 451                                 break;
 452
 453                         n++;
 454
 455                         if (isempty(line))
 456                                 continue;
 457
 458                         if (*line == ';')
 459                                 continue;
 460
 461                         (void) loader(d, *f, n, line);
 462                 }
 463         }
 464
 465         return 0;
 466 }
 467
 468 static int domain_name_cmp(char * const *a, char * const *b) {
 469         return dns_name_compare_func(*a, *b);
 470 }
 471
 472 static int dns_trust_anchor_dump(DnsTrustAnchor *d) {
 473         DnsAnswer *a;
 474
 475         assert(d);
 476
 477         if (hashmap_isempty(d->positive_by_key))
 478                 log_info("No positive trust anchors defined.");
 479         else {
 480                 log_info("Positive Trust Anchors:");
 481                 HASHMAP_FOREACH(a, d->positive_by_key) {
 482                         DnsResourceRecord *rr;
 483
 484                         DNS_ANSWER_FOREACH(rr, a)
 485                                 log_info("%s", dns_resource_record_to_string(rr));
 486                 }
 487         }
 488
 489         if (set_isempty(d->negative_by_name))
 490                 log_info("No negative trust anchors defined.");
 491         else {
 492                 _cleanup_free_ char **l = NULL, *j = NULL;
 493
 494                 l = set_get_strv(d->negative_by_name);
 495                 if (!l)
 496                         return log_oom();
 497
 498                 typesafe_qsort(l, set_size(d->negative_by_name), domain_name_cmp);
 499
 500                 j = strv_join(l, " ");
 501                 if (!j)
 502                         return log_oom();
 503
 504                 log_info("Negative trust anchors: %s", j);
 505         }
 506
 507         return 0;
 508 }
 509
 510 int dns_trust_anchor_load(DnsTrustAnchor *d) {
 511         int r;
 512
 513         assert(d);
 514
 515         /* If loading things from disk fails, we don't consider this fatal */
 516         (void) dns_trust_anchor_load_files(d, ".positive", dns_trust_anchor_load_positive);
 517         (void) dns_trust_anchor_load_files(d, ".negative", dns_trust_anchor_load_negative);
 518
 519         /* However, if the built-in DS fails, then we have a problem. */
 520         r = dns_trust_anchor_add_builtin_positive(d);
 521         if (r < 0)
 522                 return log_error_errno(r, "Failed to add built-in positive trust anchor: %m");
 523
 524         r = dns_trust_anchor_add_builtin_negative(d);
 525         if (r < 0)
 526                 return log_error_errno(r, "Failed to add built-in negative trust anchor: %m");
 527
 528         dns_trust_anchor_dump(d);
 529
 530         return 0;
 531 }
 532
 533 void dns_trust_anchor_flush(DnsTrustAnchor *d) {
 534         assert(d);
 535
 536         d->positive_by_key = hashmap_free_with_destructor(d->positive_by_key, dns_answer_unref);
 537         d->revoked_by_rr = set_free_with_destructor(d->revoked_by_rr, dns_resource_record_unref);
 538         d->negative_by_name = set_free_free(d->negative_by_name);
 539 }
 540
 541 int dns_trust_anchor_lookup_positive(DnsTrustAnchor *d, const DnsResourceKey *key, DnsAnswer **ret) {
 542         DnsAnswer *a;
 543
 544         assert(d);
 545         assert(key);
 546         assert(ret);
 547
 548         /* We only serve DS and DNSKEY RRs. */
 549         if (!IN_SET(key->type, DNS_TYPE_DS, DNS_TYPE_DNSKEY))
 550                 return 0;
 551
 552         a = hashmap_get(d->positive_by_key, key);
 553         if (!a)
 554                 return 0;
 555
 556         *ret = dns_answer_ref(a);
 557         return 1;
 558 }
 559
 560 int dns_trust_anchor_lookup_negative(DnsTrustAnchor *d, const char *name) {
 561         int r;
 562
 563         assert(d);
 564         assert(name);
 565
 566         for (;;) {
 567                 /* If the domain is listed as-is in the NTA database, then that counts */
 568                 if (set_contains(d->negative_by_name, name))
 569                         return true;
 570
 571                 /* If the domain isn't listed as NTA, but is listed as positive trust anchor, then that counts. See RFC
 572                  * 7646, section 1.1 */
 573                 if (hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_DS, name)))
 574                         return false;
 575
 576                 if (hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_KEY, name)))
 577                         return false;
 578
 579                 /* And now, let's look at the parent, and check that too */
 580                 r = dns_name_parent(&name);
 581                 if (r < 0)
 582                         return r;
 583                 if (r == 0)
 584                         break;
 585         }
 586
 587         return false;
 588 }
 589
 590 static int dns_trust_anchor_revoked_put(DnsTrustAnchor *d, DnsResourceRecord *rr) {
 591         int r;
 592
 593         assert(d);
 594
 595         r = set_ensure_put(&d->revoked_by_rr, &dns_resource_record_hash_ops, rr);
 596         if (r < 0)
 597                 return r;
 598         if (r > 0)
 599                 dns_resource_record_ref(rr);
 600
 601         return r;
 602 }
 603
 604 static int dns_trust_anchor_remove_revoked(DnsTrustAnchor *d, DnsResourceRecord *rr) {
 605         _cleanup_(dns_answer_unrefp) DnsAnswer *new_answer = NULL;
 606         DnsAnswer *old_answer;
 607         DnsAnswerItem *item;
 608         int r;
 609
 610         /* Remember that this is a revoked trust anchor RR */
 611         r = dns_trust_anchor_revoked_put(d, rr);
 612         if (r < 0)
 613                 return r;
 614
 615         /* Remove this from the positive trust anchor */
 616         old_answer = hashmap_get(d->positive_by_key, rr->key);
 617         if (!old_answer)
 618                 return 0;
 619
 620         new_answer = dns_answer_ref(old_answer);
 621
 622         r = dns_answer_remove_by_rr(&new_answer, rr);
 623         if (r <= 0)
 624                 return r;
 625
 626         /* We found the key! Warn the user */
 627         log_struct(LOG_WARNING,
 628                    "MESSAGE_ID=" SD_MESSAGE_DNSSEC_TRUST_ANCHOR_REVOKED_STR,
 629                    LOG_MESSAGE("DNSSEC trust anchor %s has been revoked.\n"
 630                                "Please update the trust anchor, or upgrade your operating system.",
 631                                strna(dns_resource_record_to_string(rr))),
 632                    "TRUST_ANCHOR=%s", dns_resource_record_to_string(rr));
 633
 634         if (dns_answer_size(new_answer) <= 0) {
 635                 assert_se(hashmap_remove(d->positive_by_key, rr->key) == old_answer);
 636                 dns_answer_unref(old_answer);
 637                 return 1;
 638         }
 639
 640         item = ordered_set_first(new_answer->items);
 641         r = hashmap_replace(d->positive_by_key, item->rr->key, new_answer);
 642         if (r < 0)
 643                 return r;
 644
 645         TAKE_PTR(new_answer);
 646         dns_answer_unref(old_answer);
 647         return 1;
 648 }
 649
 650 static int dns_trust_anchor_check_revoked_one(DnsTrustAnchor *d, DnsResourceRecord *revoked_dnskey) {
 651         DnsAnswer *a;
 652         int r;
 653
 654         assert(d);
 655         assert(revoked_dnskey);
 656         assert(revoked_dnskey->key->type == DNS_TYPE_DNSKEY);
 657         assert(revoked_dnskey->dnskey.flags & DNSKEY_FLAG_REVOKE);
 658
 659         a = hashmap_get(d->positive_by_key, revoked_dnskey->key);
 660         if (a) {
 661                 DnsResourceRecord *anchor;
 662
 663                 /* First, look for the precise DNSKEY in our trust anchor database */
 664
 665                 DNS_ANSWER_FOREACH(anchor, a) {
 666
 667                         if (anchor->dnskey.protocol != revoked_dnskey->dnskey.protocol)
 668                                 continue;
 669
 670                         if (anchor->dnskey.algorithm != revoked_dnskey->dnskey.algorithm)
 671                                 continue;
 672
 673                         if (anchor->dnskey.key_size != revoked_dnskey->dnskey.key_size)
 674                                 continue;
 675
 676                         /* Note that we allow the REVOKE bit to be
 677                          * different! It will be set in the revoked
 678                          * key, but unset in our version of it */
 679                         if (((anchor->dnskey.flags ^ revoked_dnskey->dnskey.flags) | DNSKEY_FLAG_REVOKE) != DNSKEY_FLAG_REVOKE)
 680                                 continue;
 681
 682                         if (memcmp(anchor->dnskey.key, revoked_dnskey->dnskey.key, anchor->dnskey.key_size) != 0)
 683                                 continue;
 684
 685                         dns_trust_anchor_remove_revoked(d, anchor);
 686                         break;
 687                 }
 688         }
 689
 690         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)));
 691         if (a) {
 692                 DnsResourceRecord *anchor;
 693
 694                 /* Second, look for DS RRs matching this DNSKEY in our trust anchor database */
 695
 696                 DNS_ANSWER_FOREACH(anchor, a) {
 697
 698                         /* We set mask_revoke to true here, since our
 699                          * DS fingerprint will be the one of the
 700                          * unrevoked DNSKEY, but the one we got passed
 701                          * here has the bit set. */
 702                         r = dnssec_verify_dnskey_by_ds(revoked_dnskey, anchor, true);
 703                         if (r < 0)
 704                                 return r;
 705                         if (r == 0)
 706                                 continue;
 707
 708                         dns_trust_anchor_remove_revoked(d, anchor);
 709                         break;
 710                 }
 711         }
 712
 713         return 0;
 714 }
 715
 716 int dns_trust_anchor_check_revoked(DnsTrustAnchor *d, DnsResourceRecord *dnskey, DnsAnswer *rrs) {
 717         DnsResourceRecord *rrsig;
 718         int r;
 719
 720         assert(d);
 721         assert(dnskey);
 722
 723         /* Looks if "dnskey" is a self-signed RR that has been revoked
 724          * and matches one of our trust anchor entries. If so, removes
 725          * it from the trust anchor and returns > 0. */
 726
 727         if (dnskey->key->type != DNS_TYPE_DNSKEY)
 728                 return 0;
 729
 730         /* Is this DNSKEY revoked? */
 731         if ((dnskey->dnskey.flags & DNSKEY_FLAG_REVOKE) == 0)
 732                 return 0;
 733
 734         /* Could this be interesting to us at all? If not,
 735          * there's no point in looking for and verifying a
 736          * self-signed RRSIG. */
 737         if (!dns_trust_anchor_knows_domain_positive(d, dns_resource_key_name(dnskey->key)))
 738                 return 0;
 739
 740         /* Look for a self-signed RRSIG in the other rrs belonging to this DNSKEY */
 741         DNS_ANSWER_FOREACH(rrsig, rrs) {
 742                 DnssecResult result;
 743
 744                 if (rrsig->key->type != DNS_TYPE_RRSIG)
 745                         continue;
 746
 747                 r = dnssec_rrsig_match_dnskey(rrsig, dnskey, true);
 748                 if (r < 0)
 749                         return r;
 750                 if (r == 0)
 751                         continue;
 752
 753                 r = dnssec_verify_rrset(rrs, dnskey->key, rrsig, dnskey, USEC_INFINITY, &result);
 754                 if (r < 0)
 755                         return r;
 756                 if (result != DNSSEC_VALIDATED)
 757                         continue;
 758
 759                 /* Bingo! This is a revoked self-signed DNSKEY. Let's
 760                  * see if this precise one exists in our trust anchor
 761                  * database, too. */
 762                 r = dns_trust_anchor_check_revoked_one(d, dnskey);
 763                 if (r < 0)
 764                         return r;
 765
 766                 return 1;
 767         }
 768
 769         return 0;
 770 }
 771
 772 int dns_trust_anchor_is_revoked(DnsTrustAnchor *d, DnsResourceRecord *rr) {
 773         assert(d);
 774
 775         if (!IN_SET(rr->key->type, DNS_TYPE_DS, DNS_TYPE_DNSKEY))
 776                 return 0;
 777
 778         return set_contains(d->revoked_by_rr, rr);
 779 }