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

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   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 "parse-util.h"
  13 #include "resolved-dns-trust-anchor.h"
  14 #include "resolved-dns-dnssec.h"
  15 #include "set.h"
  16 #include "string-util.h"
  17 #include "strv.h"
  18
  19 static const char trust_anchor_dirs[] = CONF_PATHS_NULSTR("dnssec-trust-anchors.d");
  20
  21 /* The first DS RR from https://data.iana.org/root-anchors/root-anchors.xml, retrieved December 2015 */
  22 static const uint8_t root_digest1[] =
  23         { 0x49, 0xAA, 0xC1, 0x1D, 0x7B, 0x6F, 0x64, 0x46, 0x70, 0x2E, 0x54, 0xA1, 0x60, 0x73, 0x71, 0x60,
  24           0x7A, 0x1A, 0x41, 0x85, 0x52, 0x00, 0xFD, 0x2C, 0xE1, 0xCD, 0xDE, 0x32, 0xF2, 0x4E, 0x8F, 0xB5 };
  25
  26 /* The second DS RR from https://data.iana.org/root-anchors/root-anchors.xml, retrieved February 2017 */
  27 static const uint8_t root_digest2[] =
  28         { 0xE0, 0x6D, 0x44, 0xB8, 0x0B, 0x8F, 0x1D, 0x39, 0xA9, 0x5C, 0x0B, 0x0D, 0x7C, 0x65, 0xD0, 0x84,
  29           0x58, 0xE8, 0x80, 0x40, 0x9B, 0xBC, 0x68, 0x34, 0x57, 0x10, 0x42, 0x37, 0xC7, 0xF8, 0xEC, 0x8D };
  30
  31 static bool dns_trust_anchor_knows_domain_positive(DnsTrustAnchor *d, const char *name) {
  32         assert(d);
  33
  34         /* Returns true if there's an entry for the specified domain
  35          * name in our trust anchor */
  36
  37         return
  38                 hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_DNSKEY, name)) ||
  39                 hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_DS, name));
  40 }
  41
  42 static int add_root_ksk(
  43                 DnsAnswer *answer,
  44                 DnsResourceKey *key,
  45                 uint16_t key_tag,
  46                 uint8_t algorithm,
  47                 uint8_t digest_type,
  48                 const void *digest,
  49                 size_t digest_size) {
  50
  51         _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
  52         int r;
  53
  54         rr = dns_resource_record_new(key);
  55         if (!rr)
  56                 return -ENOMEM;
  57
  58         rr->ds.key_tag = key_tag;
  59         rr->ds.algorithm = algorithm;
  60         rr->ds.digest_type = digest_type;
  61         rr->ds.digest_size = digest_size;
  62         rr->ds.digest = memdup(digest, rr->ds.digest_size);
  63         if (!rr->ds.digest)
  64                 return  -ENOMEM;
  65
  66         r = dns_answer_add(answer, rr, 0, DNS_ANSWER_AUTHENTICATED);
  67         if (r < 0)
  68                 return r;
  69
  70         return 0;
  71 }
  72
  73 static int dns_trust_anchor_add_builtin_positive(DnsTrustAnchor *d) {
  74         _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
  75         _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
  76         int r;
  77
  78         assert(d);
  79
  80         r = hashmap_ensure_allocated(&d->positive_by_key, &dns_resource_key_hash_ops);
  81         if (r < 0)
  82                 return r;
  83
  84         /* Only add the built-in trust anchor if there's neither a DS nor a DNSKEY defined for the root domain. That
  85          * way users have an easy way to override the root domain DS/DNSKEY data. */
  86         if (dns_trust_anchor_knows_domain_positive(d, "."))
  87                 return 0;
  88
  89         key = dns_resource_key_new(DNS_CLASS_IN, DNS_TYPE_DS, "");
  90         if (!key)
  91                 return -ENOMEM;
  92
  93         answer = dns_answer_new(2);
  94         if (!answer)
  95                 return -ENOMEM;
  96
  97         /* Add the two RRs from https://data.iana.org/root-anchors/root-anchors.xml */
  98         r = add_root_ksk(answer, key, 19036, DNSSEC_ALGORITHM_RSASHA256, DNSSEC_DIGEST_SHA256, root_digest1, sizeof(root_digest1));
  99         if (r < 0)
 100                 return r;
 101
 102         r = add_root_ksk(answer, key, 20326, DNSSEC_ALGORITHM_RSASHA256, DNSSEC_DIGEST_SHA256, root_digest2, sizeof(root_digest2));
 103         if (r < 0)
 104                 return r;
 105
 106         r = hashmap_put(d->positive_by_key, key, answer);
 107         if (r < 0)
 108                 return r;
 109
 110         answer = NULL;
 111         return 0;
 112 }
 113
 114 static int dns_trust_anchor_add_builtin_negative(DnsTrustAnchor *d) {
 115
 116         static const char private_domains[] =
 117                 /* RFC 6761 says that .test is a special domain for
 118                  * testing and not to be installed in the root zone */
 119                 "test\0"
 120
 121                 /* RFC 6761 says that these reverse IP lookup ranges
 122                  * are for private addresses, and hence should not
 123                  * show up in the root zone */
 124                 "10.in-addr.arpa\0"
 125                 "16.172.in-addr.arpa\0"
 126                 "17.172.in-addr.arpa\0"
 127                 "18.172.in-addr.arpa\0"
 128                 "19.172.in-addr.arpa\0"
 129                 "20.172.in-addr.arpa\0"
 130                 "21.172.in-addr.arpa\0"
 131                 "22.172.in-addr.arpa\0"
 132                 "23.172.in-addr.arpa\0"
 133                 "24.172.in-addr.arpa\0"
 134                 "25.172.in-addr.arpa\0"
 135                 "26.172.in-addr.arpa\0"
 136                 "27.172.in-addr.arpa\0"
 137                 "28.172.in-addr.arpa\0"
 138                 "29.172.in-addr.arpa\0"
 139                 "30.172.in-addr.arpa\0"
 140                 "31.172.in-addr.arpa\0"
 141                 "168.192.in-addr.arpa\0"
 142
 143                 /* The same, but for IPv6. */
 144                 "d.f.ip6.arpa\0"
 145
 146                 /* RFC 6762 reserves the .local domain for Multicast
 147                  * DNS, it hence cannot appear in the root zone. (Note
 148                  * that we by default do not route .local traffic to
 149                  * DNS anyway, except when a configured search domain
 150                  * suggests so.) */
 151                 "local\0"
 152
 153                 /* These two are well known, popular private zone
 154                  * TLDs, that are blocked from delegation, according
 155                  * to:
 156                  * http://icannwiki.com/Name_Collision#NGPC_Resolution
 157                  *
 158                  * There's also ongoing work on making this official
 159                  * in an RRC:
 160                  * https://www.ietf.org/archive/id/draft-chapin-additional-reserved-tlds-02.txt */
 161                 "home\0"
 162                 "corp\0"
 163
 164                 /* The following four TLDs are suggested for private
 165                  * zones in RFC 6762, Appendix G, and are hence very
 166                  * unlikely to be made official TLDs any day soon */
 167                 "lan\0"
 168                 "intranet\0"
 169                 "internal\0"
 170                 "private\0";
 171
 172         const char *name;
 173         int r;
 174
 175         assert(d);
 176
 177         /* Only add the built-in trust anchor if there's no negative
 178          * trust anchor defined at all. This enables easy overriding
 179          * of negative trust anchors. */
 180
 181         if (set_size(d->negative_by_name) > 0)
 182                 return 0;
 183
 184         r = set_ensure_allocated(&d->negative_by_name, &dns_name_hash_ops);
 185         if (r < 0)
 186                 return r;
 187
 188         /* We add a couple of domains as default negative trust
 189          * anchors, where it's very unlikely they will be installed in
 190          * the root zone. If they exist they must be private, and thus
 191          * unsigned. */
 192
 193         NULSTR_FOREACH(name, private_domains) {
 194
 195                 if (dns_trust_anchor_knows_domain_positive(d, name))
 196                         continue;
 197
 198                 r = set_put_strdup(d->negative_by_name, name);
 199                 if (r < 0)
 200                         return r;
 201         }
 202
 203         return 0;
 204 }
 205
 206 static int dns_trust_anchor_load_positive(DnsTrustAnchor *d, const char *path, unsigned line, const char *s) {
 207         _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
 208         _cleanup_free_ char *domain = NULL, *class = NULL, *type = NULL;
 209         _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
 210         DnsAnswer *old_answer = NULL;
 211         const char *p = s;
 212         int r;
 213
 214         assert(d);
 215         assert(line);
 216
 217         r = extract_first_word(&p, &domain, NULL, EXTRACT_QUOTES);
 218         if (r < 0)
 219                 return log_warning_errno(r, "Unable to parse domain in line %s:%u: %m", path, line);
 220
 221         r = dns_name_is_valid(domain);
 222         if (r < 0)
 223                 return log_warning_errno(r, "Failed to chack validity of domain name '%s', at line %s:%u, ignoring line: %m", domain, path, line);
 224         if (r == 0) {
 225                 log_warning("Domain name %s is invalid, at line %s:%u, ignoring line.", domain, path, line);
 226                 return -EINVAL;
 227         }
 228
 229         r = extract_many_words(&p, NULL, 0, &class, &type, NULL);
 230         if (r < 0)
 231                 return log_warning_errno(r, "Unable to parse class and type in line %s:%u: %m", path, line);
 232         if (r != 2) {
 233                 log_warning("Missing class or type in line %s:%u", path, line);
 234                 return -EINVAL;
 235         }
 236
 237         if (!strcaseeq(class, "IN")) {
 238                 log_warning("RR class %s is not supported, ignoring line %s:%u.", class, path, line);
 239                 return -EINVAL;
 240         }
 241
 242         if (strcaseeq(type, "DS")) {
 243                 _cleanup_free_ char *key_tag = NULL, *algorithm = NULL, *digest_type = NULL;
 244                 _cleanup_free_ void *dd = NULL;
 245                 uint16_t kt;
 246                 int a, dt;
 247                 size_t l;
 248
 249                 r = extract_many_words(&p, NULL, 0, &key_tag, &algorithm, &digest_type, NULL);
 250                 if (r < 0) {
 251                         log_warning_errno(r, "Failed to parse DS parameters on line %s:%u: %m", path, line);
 252                         return -EINVAL;
 253                 }
 254                 if (r != 3) {
 255                         log_warning("Missing DS parameters on line %s:%u", path, line);
 256                         return -EINVAL;
 257                 }
 258
 259                 r = safe_atou16(key_tag, &kt);
 260                 if (r < 0)
 261                         return log_warning_errno(r, "Failed to parse DS key tag %s on line %s:%u: %m", key_tag, path, line);
 262
 263                 a = dnssec_algorithm_from_string(algorithm);
 264                 if (a < 0) {
 265                         log_warning("Failed to parse DS algorithm %s on line %s:%u", algorithm, path, line);
 266                         return -EINVAL;
 267                 }
 268
 269                 dt = dnssec_digest_from_string(digest_type);
 270                 if (dt < 0) {
 271                         log_warning("Failed to parse DS digest type %s on line %s:%u", digest_type, path, line);
 272                         return -EINVAL;
 273                 }
 274
 275                 if (isempty(p)) {
 276                         log_warning("Missing DS digest on line %s:%u", path, line);
 277                         return -EINVAL;
 278                 }
 279
 280                 r = unhexmem(p, strlen(p), &dd, &l);
 281                 if (r < 0) {
 282                         log_warning("Failed to parse DS digest %s on line %s:%u", p, path, line);
 283                         return -EINVAL;
 284                 }
 285
 286                 rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_DS, domain);
 287                 if (!rr)
 288                         return log_oom();
 289
 290                 rr->ds.key_tag = kt;
 291                 rr->ds.algorithm = a;
 292                 rr->ds.digest_type = dt;
 293                 rr->ds.digest_size = l;
 294                 rr->ds.digest = TAKE_PTR(dd);
 295
 296         } else if (strcaseeq(type, "DNSKEY")) {
 297                 _cleanup_free_ char *flags = NULL, *protocol = NULL, *algorithm = NULL;
 298                 _cleanup_free_ void *k = NULL;
 299                 uint16_t f;
 300                 size_t l;
 301                 int a;
 302
 303                 r = extract_many_words(&p, NULL, 0, &flags, &protocol, &algorithm, NULL);
 304                 if (r < 0)
 305                         return log_warning_errno(r, "Failed to parse DNSKEY parameters on line %s:%u: %m", path, line);
 306                 if (r != 3) {
 307                         log_warning("Missing DNSKEY parameters on line %s:%u", path, line);
 308                         return -EINVAL;
 309                 }
 310
 311                 if (!streq(protocol, "3")) {
 312                         log_warning("DNSKEY Protocol is not 3 on line %s:%u", path, line);
 313                         return -EINVAL;
 314                 }
 315
 316                 r = safe_atou16(flags, &f);
 317                 if (r < 0)
 318                         return log_warning_errno(r, "Failed to parse DNSKEY flags field %s on line %s:%u", flags, path, line);
 319                 if ((f & DNSKEY_FLAG_ZONE_KEY) == 0) {
 320                         log_warning("DNSKEY lacks zone key bit set on line %s:%u", path, line);
 321                         return -EINVAL;
 322                 }
 323                 if ((f & DNSKEY_FLAG_REVOKE)) {
 324                         log_warning("DNSKEY is already revoked on line %s:%u", path, line);
 325                         return -EINVAL;
 326                 }
 327
 328                 a = dnssec_algorithm_from_string(algorithm);
 329                 if (a < 0) {
 330                         log_warning("Failed to parse DNSKEY algorithm %s on line %s:%u", algorithm, path, line);
 331                         return -EINVAL;
 332                 }
 333
 334                 if (isempty(p)) {
 335                         log_warning("Missing DNSKEY key on line %s:%u", path, line);
 336                         return -EINVAL;
 337                 }
 338
 339                 r = unbase64mem(p, strlen(p), &k, &l);
 340                 if (r < 0)
 341                         return log_warning_errno(r, "Failed to parse DNSKEY key data %s on line %s:%u", p, path, line);
 342
 343                 rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_DNSKEY, domain);
 344                 if (!rr)
 345                         return log_oom();
 346
 347                 rr->dnskey.flags = f;
 348                 rr->dnskey.protocol = 3;
 349                 rr->dnskey.algorithm = a;
 350                 rr->dnskey.key_size = l;
 351                 rr->dnskey.key = TAKE_PTR(k);
 352
 353         } else {
 354                 log_warning("RR type %s is not supported, ignoring line %s:%u.", type, path, line);
 355                 return -EINVAL;
 356         }
 357
 358         r = hashmap_ensure_allocated(&d->positive_by_key, &dns_resource_key_hash_ops);
 359         if (r < 0)
 360                 return log_oom();
 361
 362         old_answer = hashmap_get(d->positive_by_key, rr->key);
 363         answer = dns_answer_ref(old_answer);
 364
 365         r = dns_answer_add_extend(&answer, rr, 0, DNS_ANSWER_AUTHENTICATED);
 366         if (r < 0)
 367                 return log_error_errno(r, "Failed to add trust anchor RR: %m");
 368
 369         r = hashmap_replace(d->positive_by_key, rr->key, answer);
 370         if (r < 0)
 371                 return log_error_errno(r, "Failed to add answer to trust anchor: %m");
 372
 373         old_answer = dns_answer_unref(old_answer);
 374         answer = NULL;
 375
 376         return 0;
 377 }
 378
 379 static int dns_trust_anchor_load_negative(DnsTrustAnchor *d, const char *path, unsigned line, const char *s) {
 380         _cleanup_free_ char *domain = NULL;
 381         const char *p = s;
 382         int r;
 383
 384         assert(d);
 385         assert(line);
 386
 387         r = extract_first_word(&p, &domain, NULL, EXTRACT_QUOTES);
 388         if (r < 0)
 389                 return log_warning_errno(r, "Unable to parse line %s:%u: %m", path, line);
 390
 391         r = dns_name_is_valid(domain);
 392         if (r < 0)
 393                 return log_warning_errno(r, "Failed to chack validity of domain name '%s', at line %s:%u, ignoring line: %m", domain, path, line);
 394         if (r == 0) {
 395                 log_warning("Domain name %s is invalid, at line %s:%u, ignoring line.", domain, path, line);
 396                 return -EINVAL;
 397         }
 398
 399         if (!isempty(p)) {
 400                 log_warning("Trailing garbage at line %s:%u, ignoring line.", path, line);
 401                 return -EINVAL;
 402         }
 403
 404         r = set_ensure_allocated(&d->negative_by_name, &dns_name_hash_ops);
 405         if (r < 0)
 406                 return log_oom();
 407
 408         r = set_put(d->negative_by_name, domain);
 409         if (r < 0)
 410                 return log_oom();
 411         if (r > 0)
 412                 domain = NULL;
 413
 414         return 0;
 415 }
 416
 417 static int dns_trust_anchor_load_files(
 418                 DnsTrustAnchor *d,
 419                 const char *suffix,
 420                 int (*loader)(DnsTrustAnchor *d, const char *path, unsigned n, const char *line)) {
 421
 422         _cleanup_strv_free_ char **files = NULL;
 423         char **f;
 424         int r;
 425
 426         assert(d);
 427         assert(suffix);
 428         assert(loader);
 429
 430         r = conf_files_list_nulstr(&files, suffix, NULL, 0, trust_anchor_dirs);
 431         if (r < 0)
 432                 return log_error_errno(r, "Failed to enumerate %s trust anchor files: %m", suffix);
 433
 434         STRV_FOREACH(f, files) {
 435                 _cleanup_fclose_ FILE *g = NULL;
 436                 char line[LINE_MAX];
 437                 unsigned n = 0;
 438
 439                 g = fopen(*f, "r");
 440                 if (!g) {
 441                         if (errno == ENOENT)
 442                                 continue;
 443
 444                         log_warning_errno(errno, "Failed to open %s: %m", *f);
 445                         continue;
 446                 }
 447
 448                 FOREACH_LINE(line, g, log_warning_errno(errno, "Failed to read %s, ignoring: %m", *f)) {
 449                         char *l;
 450
 451                         n++;
 452
 453                         l = strstrip(line);
 454                         if (isempty(l))
 455                                 continue;
 456
 457                         if (*l == ';')
 458                                 continue;
 459
 460                         (void) loader(d, *f, n, l);
 461                 }
 462         }
 463
 464         return 0;
 465 }
 466
 467 static int domain_name_cmp(const void *a, const void *b) {
 468         char **x = (char**) a, **y = (char**) b;
 469
 470         return dns_name_compare_func(*x, *y);
 471 }
 472
 473 static int dns_trust_anchor_dump(DnsTrustAnchor *d) {
 474         DnsAnswer *a;
 475         Iterator i;
 476
 477         assert(d);
 478
 479         if (hashmap_isempty(d->positive_by_key))
 480                 log_info("No positive trust anchors defined.");
 481         else {
 482                 log_info("Positive Trust Anchors:");
 483                 HASHMAP_FOREACH(a, d->positive_by_key, i) {
 484                         DnsResourceRecord *rr;
 485
 486                         DNS_ANSWER_FOREACH(rr, a)
 487                                 log_info("%s", dns_resource_record_to_string(rr));
 488                 }
 489         }
 490
 491         if (set_isempty(d->negative_by_name))
 492                 log_info("No negative trust anchors defined.");
 493         else {
 494                 _cleanup_free_ char **l = NULL, *j = NULL;
 495
 496                 l = set_get_strv(d->negative_by_name);
 497                 if (!l)
 498                         return log_oom();
 499
 500                 qsort_safe(l, set_size(d->negative_by_name), sizeof(char*), domain_name_cmp);
 501
 502                 j = strv_join(l, " ");
 503                 if (!j)
 504                         return log_oom();
 505
 506                 log_info("Negative trust anchors: %s", j);
 507         }
 508
 509         return 0;
 510 }
 511
 512 int dns_trust_anchor_load(DnsTrustAnchor *d) {
 513         int r;
 514
 515         assert(d);
 516
 517         /* If loading things from disk fails, we don't consider this fatal */
 518         (void) dns_trust_anchor_load_files(d, ".positive", dns_trust_anchor_load_positive);
 519         (void) dns_trust_anchor_load_files(d, ".negative", dns_trust_anchor_load_negative);
 520
 521         /* However, if the built-in DS fails, then we have a problem. */
 522         r = dns_trust_anchor_add_builtin_positive(d);
 523         if (r < 0)
 524                 return log_error_errno(r, "Failed to add built-in positive trust anchor: %m");
 525
 526         r = dns_trust_anchor_add_builtin_negative(d);
 527         if (r < 0)
 528                 return log_error_errno(r, "Failed to add built-in negative trust anchor: %m");
 529
 530         dns_trust_anchor_dump(d);
 531
 532         return 0;
 533 }
 534
 535 void dns_trust_anchor_flush(DnsTrustAnchor *d) {
 536         assert(d);
 537
 538         d->positive_by_key = hashmap_free_with_destructor(d->positive_by_key, dns_answer_unref);
 539         d->revoked_by_rr = set_free_with_destructor(d->revoked_by_rr, dns_resource_record_unref);
 540         d->negative_by_name = set_free_free(d->negative_by_name);
 541 }
 542
 543 int dns_trust_anchor_lookup_positive(DnsTrustAnchor *d, const DnsResourceKey *key, DnsAnswer **ret) {
 544         DnsAnswer *a;
 545
 546         assert(d);
 547         assert(key);
 548         assert(ret);
 549
 550         /* We only serve DS and DNSKEY RRs. */
 551         if (!IN_SET(key->type, DNS_TYPE_DS, DNS_TYPE_DNSKEY))
 552                 return 0;
 553
 554         a = hashmap_get(d->positive_by_key, key);
 555         if (!a)
 556                 return 0;
 557
 558         *ret = dns_answer_ref(a);
 559         return 1;
 560 }
 561
 562 int dns_trust_anchor_lookup_negative(DnsTrustAnchor *d, const char *name) {
 563         int r;
 564
 565         assert(d);
 566         assert(name);
 567
 568         for (;;) {
 569                 /* If the domain is listed as-is in the NTA database, then that counts */
 570                 if (set_contains(d->negative_by_name, name))
 571                         return true;
 572
 573                 /* If the domain isn't listed as NTA, but is listed as positive trust anchor, then that counts. See RFC
 574                  * 7646, section 1.1 */
 575                 if (hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_DS, name)))
 576                         return false;
 577
 578                 if (hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_KEY, name)))
 579                         return false;
 580
 581                 /* And now, let's look at the parent, and check that too */
 582                 r = dns_name_parent(&name);
 583                 if (r < 0)
 584                         return r;
 585                 if (r == 0)
 586                         break;
 587         }
 588
 589         return false;
 590 }
 591
 592 static int dns_trust_anchor_revoked_put(DnsTrustAnchor *d, DnsResourceRecord *rr) {
 593         int r;
 594
 595         assert(d);
 596
 597         r = set_ensure_allocated(&d->revoked_by_rr, &dns_resource_record_hash_ops);
 598         if (r < 0)
 599                 return r;
 600
 601         r = set_put(d->revoked_by_rr, rr);
 602         if (r < 0)
 603                 return r;
 604         if (r > 0)
 605                 dns_resource_record_ref(rr);
 606
 607         return r;
 608 }
 609
 610 static int dns_trust_anchor_remove_revoked(DnsTrustAnchor *d, DnsResourceRecord *rr) {
 611         _cleanup_(dns_answer_unrefp) DnsAnswer *new_answer = NULL;
 612         DnsAnswer *old_answer;
 613         int r;
 614
 615         /* Remember that this is a revoked trust anchor RR */
 616         r = dns_trust_anchor_revoked_put(d, rr);
 617         if (r < 0)
 618                 return r;
 619
 620         /* Remove this from the positive trust anchor */
 621         old_answer = hashmap_get(d->positive_by_key, rr->key);
 622         if (!old_answer)
 623                 return 0;
 624
 625         new_answer = dns_answer_ref(old_answer);
 626
 627         r = dns_answer_remove_by_rr(&new_answer, rr);
 628         if (r <= 0)
 629                 return r;
 630
 631         /* We found the key! Warn the user */
 632         log_struct(LOG_WARNING,
 633                    "MESSAGE_ID=" SD_MESSAGE_DNSSEC_TRUST_ANCHOR_REVOKED_STR,
 634                    LOG_MESSAGE("DNSSEC trust anchor %s has been revoked.\n"
 635                                "Please update the trust anchor, or upgrade your operating system.",
 636                                strna(dns_resource_record_to_string(rr))),
 637                    "TRUST_ANCHOR=%s", dns_resource_record_to_string(rr));
 638
 639         if (dns_answer_size(new_answer) <= 0) {
 640                 assert_se(hashmap_remove(d->positive_by_key, rr->key) == old_answer);
 641                 dns_answer_unref(old_answer);
 642                 return 1;
 643         }
 644
 645         r = hashmap_replace(d->positive_by_key, new_answer->items[0].rr->key, new_answer);
 646         if (r < 0)
 647                 return r;
 648
 649         new_answer = NULL;
 650         dns_answer_unref(old_answer);
 651         return 1;
 652 }
 653
 654 static int dns_trust_anchor_check_revoked_one(DnsTrustAnchor *d, DnsResourceRecord *revoked_dnskey) {
 655         DnsAnswer *a;
 656         int r;
 657
 658         assert(d);
 659         assert(revoked_dnskey);
 660         assert(revoked_dnskey->key->type == DNS_TYPE_DNSKEY);
 661         assert(revoked_dnskey->dnskey.flags & DNSKEY_FLAG_REVOKE);
 662
 663         a = hashmap_get(d->positive_by_key, revoked_dnskey->key);
 664         if (a) {
 665                 DnsResourceRecord *anchor;
 666
 667                 /* First, look for the precise DNSKEY in our trust anchor database */
 668
 669                 DNS_ANSWER_FOREACH(anchor, a) {
 670
 671                         if (anchor->dnskey.protocol != revoked_dnskey->dnskey.protocol)
 672                                 continue;
 673
 674                         if (anchor->dnskey.algorithm != revoked_dnskey->dnskey.algorithm)
 675                                 continue;
 676
 677                         if (anchor->dnskey.key_size != revoked_dnskey->dnskey.key_size)
 678                                 continue;
 679
 680                         /* Note that we allow the REVOKE bit to be
 681                          * different! It will be set in the revoked
 682                          * key, but unset in our version of it */
 683                         if (((anchor->dnskey.flags ^ revoked_dnskey->dnskey.flags) | DNSKEY_FLAG_REVOKE) != DNSKEY_FLAG_REVOKE)
 684                                 continue;
 685
 686                         if (memcmp(anchor->dnskey.key, revoked_dnskey->dnskey.key, anchor->dnskey.key_size) != 0)
 687                                 continue;
 688
 689                         dns_trust_anchor_remove_revoked(d, anchor);
 690                         break;
 691                 }
 692         }
 693
 694         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)));
 695         if (a) {
 696                 DnsResourceRecord *anchor;
 697
 698                 /* Second, look for DS RRs matching this DNSKEY in our trust anchor database */
 699
 700                 DNS_ANSWER_FOREACH(anchor, a) {
 701
 702                         /* We set mask_revoke to true here, since our
 703                          * DS fingerprint will be the one of the
 704                          * unrevoked DNSKEY, but the one we got passed
 705                          * here has the bit set. */
 706                         r = dnssec_verify_dnskey_by_ds(revoked_dnskey, anchor, true);
 707                         if (r < 0)
 708                                 return r;
 709                         if (r == 0)
 710                                 continue;
 711
 712                         dns_trust_anchor_remove_revoked(d, anchor);
 713                         break;
 714                 }
 715         }
 716
 717         return 0;
 718 }
 719
 720 int dns_trust_anchor_check_revoked(DnsTrustAnchor *d, DnsResourceRecord *dnskey, DnsAnswer *rrs) {
 721         DnsResourceRecord *rrsig;
 722         int r;
 723
 724         assert(d);
 725         assert(dnskey);
 726
 727         /* Looks if "dnskey" is a self-signed RR that has been revoked
 728          * and matches one of our trust anchor entries. If so, removes
 729          * it from the trust anchor and returns > 0. */
 730
 731         if (dnskey->key->type != DNS_TYPE_DNSKEY)
 732                 return 0;
 733
 734         /* Is this DNSKEY revoked? */
 735         if ((dnskey->dnskey.flags & DNSKEY_FLAG_REVOKE) == 0)
 736                 return 0;
 737
 738         /* Could this be interesting to us at all? If not,
 739          * there's no point in looking for and verifying a
 740          * self-signed RRSIG. */
 741         if (!dns_trust_anchor_knows_domain_positive(d, dns_resource_key_name(dnskey->key)))
 742                 return 0;
 743
 744         /* Look for a self-signed RRSIG in the other rrs belonging to this DNSKEY */
 745         DNS_ANSWER_FOREACH(rrsig, rrs) {
 746                 DnssecResult result;
 747
 748                 if (rrsig->key->type != DNS_TYPE_RRSIG)
 749                         continue;
 750
 751                 r = dnssec_rrsig_match_dnskey(rrsig, dnskey, true);
 752                 if (r < 0)
 753                         return r;
 754                 if (r == 0)
 755                         continue;
 756
 757                 r = dnssec_verify_rrset(rrs, dnskey->key, rrsig, dnskey, USEC_INFINITY, &result);
 758                 if (r < 0)
 759                         return r;
 760                 if (result != DNSSEC_VALIDATED)
 761                         continue;
 762
 763                 /* Bingo! This is a revoked self-signed DNSKEY. Let's
 764                  * see if this precise one exists in our trust anchor
 765                  * database, too. */
 766                 r = dns_trust_anchor_check_revoked_one(d, dnskey);
 767                 if (r < 0)
 768                         return r;
 769
 770                 return 1;
 771         }
 772
 773         return 0;
 774 }
 775
 776 int dns_trust_anchor_is_revoked(DnsTrustAnchor *d, DnsResourceRecord *rr) {
 777         assert(d);
 778
 779         if (!IN_SET(rr->key->type, DNS_TYPE_DS, DNS_TYPE_DNSKEY))
 780                 return 0;
 781
 782         return set_contains(d->revoked_by_rr, rr);
 783 }