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

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2015 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <sd-messages.h>
  21
  22 #include "alloc-util.h"
  23 #include "conf-files.h"
  24 #include "def.h"
  25 #include "dns-domain.h"
  26 #include "fd-util.h"
  27 #include "fileio.h"
  28 #include "hexdecoct.h"
  29 #include "parse-util.h"
  30 #include "resolved-dns-trust-anchor.h"
  31 #include "resolved-dns-dnssec.h"
  32 #include "set.h"
  33 #include "string-util.h"
  34 #include "strv.h"
  35
  36 static const char trust_anchor_dirs[] = CONF_PATHS_NULSTR("dnssec-trust-anchors.d");
  37
  38 /* The DS RR from https://data.iana.org/root-anchors/root-anchors.xml, retrieved December 2015 */
  39 static const uint8_t root_digest[] =
  40         { 0x49, 0xAA, 0xC1, 0x1D, 0x7B, 0x6F, 0x64, 0x46, 0x70, 0x2E, 0x54, 0xA1, 0x60, 0x73, 0x71, 0x60,
  41           0x7A, 0x1A, 0x41, 0x85, 0x52, 0x00, 0xFD, 0x2C, 0xE1, 0xCD, 0xDE, 0x32, 0xF2, 0x4E, 0x8F, 0xB5 };
  42
  43 static bool dns_trust_anchor_knows_domain_positive(DnsTrustAnchor *d, const char *name) {
  44         assert(d);
  45
  46         /* Returns true if there's an entry for the specified domain
  47          * name in our trust anchor */
  48
  49         return
  50                 hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_DNSKEY, name)) ||
  51                 hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_DS, name));
  52 }
  53
  54 static int dns_trust_anchor_add_builtin_positive(DnsTrustAnchor *d) {
  55         _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
  56         _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
  57         int r;
  58
  59         assert(d);
  60
  61         r = hashmap_ensure_allocated(&d->positive_by_key, &dns_resource_key_hash_ops);
  62         if (r < 0)
  63                 return r;
  64
  65         /* Only add the built-in trust anchor if there's neither a DS
  66          * nor a DNSKEY defined for the root domain. That way users
  67          * have an easy way to override the root domain DS/DNSKEY
  68          * data. */
  69         if (dns_trust_anchor_knows_domain_positive(d, "."))
  70                 return 0;
  71
  72         /* Add the RR from https://data.iana.org/root-anchors/root-anchors.xml */
  73         rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_DS, "");
  74         if (!rr)
  75                 return -ENOMEM;
  76
  77         rr->ds.key_tag = 19036;
  78         rr->ds.algorithm = DNSSEC_ALGORITHM_RSASHA256;
  79         rr->ds.digest_type = DNSSEC_DIGEST_SHA256;
  80         rr->ds.digest_size = sizeof(root_digest);
  81         rr->ds.digest = memdup(root_digest, rr->ds.digest_size);
  82         if (!rr->ds.digest)
  83                 return  -ENOMEM;
  84
  85         answer = dns_answer_new(1);
  86         if (!answer)
  87                 return -ENOMEM;
  88
  89         r = dns_answer_add(answer, rr, 0, DNS_ANSWER_AUTHENTICATED);
  90         if (r < 0)
  91                 return r;
  92
  93         r = hashmap_put(d->positive_by_key, rr->key, answer);
  94         if (r < 0)
  95                 return r;
  96
  97         answer = NULL;
  98         return 0;
  99 }
 100
 101 static int dns_trust_anchor_add_builtin_negative(DnsTrustAnchor *d) {
 102
 103         static const char private_domains[] =
 104                 /* RFC 6761 says that .test is a special domain for
 105                  * testing and not to be installed in the root zone */
 106                 "test\0"
 107
 108                 /* RFC 6761 says that these reverse IP lookup ranges
 109                  * are for private addresses, and hence should not
 110                  * show up in the root zone */
 111                 "10.in-addr.arpa\0"
 112                 "16.172.in-addr.arpa\0"
 113                 "17.172.in-addr.arpa\0"
 114                 "18.172.in-addr.arpa\0"
 115                 "19.172.in-addr.arpa\0"
 116                 "20.172.in-addr.arpa\0"
 117                 "21.172.in-addr.arpa\0"
 118                 "22.172.in-addr.arpa\0"
 119                 "23.172.in-addr.arpa\0"
 120                 "24.172.in-addr.arpa\0"
 121                 "25.172.in-addr.arpa\0"
 122                 "26.172.in-addr.arpa\0"
 123                 "27.172.in-addr.arpa\0"
 124                 "28.172.in-addr.arpa\0"
 125                 "29.172.in-addr.arpa\0"
 126                 "30.172.in-addr.arpa\0"
 127                 "31.172.in-addr.arpa\0"
 128                 "168.192.in-addr.arpa\0"
 129
 130                 /* The same, but for IPv6. */
 131                 "d.f.ip6.arpa\0"
 132
 133                 /* RFC 6762 reserves the .local domain for Multicast
 134                  * DNS, it hence cannot appear in the root zone. (Note
 135                  * that we by default do not route .local traffic to
 136                  * DNS anyway, except when a configured search domain
 137                  * suggests so.) */
 138                 "local\0"
 139
 140                 /* These two are well known, popular private zone
 141                  * TLDs, that are blocked from delegation, according
 142                  * to:
 143                  * http://icannwiki.com/Name_Collision#NGPC_Resolution
 144                  *
 145                  * There's also ongoing work on making this official
 146                  * in an RRC:
 147                  * https://www.ietf.org/archive/id/draft-chapin-additional-reserved-tlds-02.txt */
 148                 "home\0"
 149                 "corp\0"
 150
 151                 /* The following four TLDs are suggested for private
 152                  * zones in RFC 6762, Appendix G, and are hence very
 153                  * unlikely to be made official TLDs any day soon */
 154                 "lan\0"
 155                 "intranet\0"
 156                 "internal\0"
 157                 "private\0";
 158
 159         const char *name;
 160         int r;
 161
 162         assert(d);
 163
 164         /* Only add the built-in trust anchor if there's no negative
 165          * trust anchor defined at all. This enables easy overriding
 166          * of negative trust anchors. */
 167
 168         if (set_size(d->negative_by_name) > 0)
 169                 return 0;
 170
 171         r = set_ensure_allocated(&d->negative_by_name, &dns_name_hash_ops);
 172         if (r < 0)
 173                 return r;
 174
 175         /* We add a couple of domains as default negative trust
 176          * anchors, where it's very unlikely they will be installed in
 177          * the root zone. If they exist they must be private, and thus
 178          * unsigned. */
 179
 180         NULSTR_FOREACH(name, private_domains) {
 181
 182                 if (dns_trust_anchor_knows_domain_positive(d, name))
 183                         continue;
 184
 185                 r = set_put_strdup(d->negative_by_name, name);
 186                 if (r < 0)
 187                         return r;
 188         }
 189
 190         return 0;
 191 }
 192
 193 static int dns_trust_anchor_load_positive(DnsTrustAnchor *d, const char *path, unsigned line, const char *s) {
 194         _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
 195         _cleanup_free_ char *domain = NULL, *class = NULL, *type = NULL;
 196         _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
 197         DnsAnswer *old_answer = NULL;
 198         const char *p = s;
 199         int r;
 200
 201         assert(d);
 202         assert(line);
 203
 204         r = extract_first_word(&p, &domain, NULL, EXTRACT_QUOTES);
 205         if (r < 0)
 206                 return log_warning_errno(r, "Unable to parse domain in line %s:%u: %m", path, line);
 207
 208         if (!dns_name_is_valid(domain)) {
 209                 log_warning("Domain name %s is invalid, at line %s:%u, ignoring line.", domain, path, line);
 210                 return -EINVAL;
 211         }
 212
 213         r = extract_many_words(&p, NULL, 0, &class, &type, NULL);
 214         if (r < 0)
 215                 return log_warning_errno(r, "Unable to parse class and type in line %s:%u: %m", path, line);
 216         if (r != 2) {
 217                 log_warning("Missing class or type in line %s:%u", path, line);
 218                 return -EINVAL;
 219         }
 220
 221         if (!strcaseeq(class, "IN")) {
 222                 log_warning("RR class %s is not supported, ignoring line %s:%u.", class, path, line);
 223                 return -EINVAL;
 224         }
 225
 226         if (strcaseeq(type, "DS")) {
 227                 _cleanup_free_ char *key_tag = NULL, *algorithm = NULL, *digest_type = NULL, *digest = NULL;
 228                 _cleanup_free_ void *dd = NULL;
 229                 uint16_t kt;
 230                 int a, dt;
 231                 size_t l;
 232
 233                 r = extract_many_words(&p, NULL, 0, &key_tag, &algorithm, &digest_type, &digest, NULL);
 234                 if (r < 0) {
 235                         log_warning_errno(r, "Failed to parse DS parameters on line %s:%u: %m", path, line);
 236                         return -EINVAL;
 237                 }
 238                 if (r != 4) {
 239                         log_warning("Missing DS parameters on line %s:%u", path, line);
 240                         return -EINVAL;
 241                 }
 242
 243                 r = safe_atou16(key_tag, &kt);
 244                 if (r < 0)
 245                         return log_warning_errno(r, "Failed to parse DS key tag %s on line %s:%u: %m", key_tag, path, line);
 246
 247                 a = dnssec_algorithm_from_string(algorithm);
 248                 if (a < 0) {
 249                         log_warning("Failed to parse DS algorithm %s on line %s:%u", algorithm, path, line);
 250                         return -EINVAL;
 251                 }
 252
 253                 dt = dnssec_digest_from_string(digest_type);
 254                 if (dt < 0) {
 255                         log_warning("Failed to parse DS digest type %s on line %s:%u", digest_type, path, line);
 256                         return -EINVAL;
 257                 }
 258
 259                 r = unhexmem(digest, strlen(digest), &dd, &l);
 260                 if (r < 0) {
 261                         log_warning("Failed to parse DS digest %s on line %s:%u", digest, path, line);
 262                         return -EINVAL;
 263                 }
 264
 265                 rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_DS, domain);
 266                 if (!rr)
 267                         return log_oom();
 268
 269                 rr->ds.key_tag = kt;
 270                 rr->ds.algorithm = a;
 271                 rr->ds.digest_type = dt;
 272                 rr->ds.digest_size = l;
 273                 rr->ds.digest = dd;
 274                 dd = NULL;
 275
 276         } else if (strcaseeq(type, "DNSKEY")) {
 277                 _cleanup_free_ char *flags = NULL, *protocol = NULL, *algorithm = NULL, *key = NULL;
 278                 _cleanup_free_ void *k = NULL;
 279                 uint16_t f;
 280                 size_t l;
 281                 int a;
 282
 283                 r = extract_many_words(&p, NULL, 0, &flags, &protocol, &algorithm, &key, NULL);
 284                 if (r < 0)
 285                         return log_warning_errno(r, "Failed to parse DNSKEY parameters on line %s:%u: %m", path, line);
 286                 if (r != 4) {
 287                         log_warning("Missing DNSKEY parameters on line %s:%u", path, line);
 288                         return -EINVAL;
 289                 }
 290
 291                 if (!streq(protocol, "3")) {
 292                         log_warning("DNSKEY Protocol is not 3 on line %s:%u", path, line);
 293                         return -EINVAL;
 294                 }
 295
 296                 r = safe_atou16(flags, &f);
 297                 if (r < 0)
 298                         return log_warning_errno(r, "Failed to parse DNSKEY flags field %s on line %s:%u", flags, path, line);
 299                 if ((f & DNSKEY_FLAG_ZONE_KEY) == 0) {
 300                         log_warning("DNSKEY lacks zone key bit set on line %s:%u", path, line);
 301                         return -EINVAL;
 302                 }
 303                 if ((f & DNSKEY_FLAG_REVOKE)) {
 304                         log_warning("DNSKEY is already revoked on line %s:%u", path, line);
 305                         return -EINVAL;
 306                 }
 307
 308                 a = dnssec_algorithm_from_string(algorithm);
 309                 if (a < 0) {
 310                         log_warning("Failed to parse DNSKEY algorithm %s on line %s:%u", algorithm, path, line);
 311                         return -EINVAL;
 312                 }
 313
 314                 r = unbase64mem(key, strlen(key), &k, &l);
 315                 if (r < 0)
 316                         return log_warning_errno(r, "Failed to parse DNSKEY key data %s on line %s:%u", key, path, line);
 317
 318                 rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_DNSKEY, domain);
 319                 if (!rr)
 320                         return log_oom();
 321
 322                 rr->dnskey.flags = f;
 323                 rr->dnskey.protocol = 3;
 324                 rr->dnskey.algorithm = a;
 325                 rr->dnskey.key_size = l;
 326                 rr->dnskey.key = k;
 327                 k = NULL;
 328
 329         } else {
 330                 log_warning("RR type %s is not supported, ignoring line %s:%u.", type, path, line);
 331                 return -EINVAL;
 332         }
 333
 334         if (!isempty(p)) {
 335                 log_warning("Trailing garbage on line %s:%u, ignoring line.", path, line);
 336                 return -EINVAL;
 337         }
 338
 339         r = hashmap_ensure_allocated(&d->positive_by_key, &dns_resource_key_hash_ops);
 340         if (r < 0)
 341                 return log_oom();
 342
 343         old_answer = hashmap_get(d->positive_by_key, rr->key);
 344         answer = dns_answer_ref(old_answer);
 345
 346         r = dns_answer_add_extend(&answer, rr, 0, DNS_ANSWER_AUTHENTICATED);
 347         if (r < 0)
 348                 return log_error_errno(r, "Failed to add trust anchor RR: %m");
 349
 350         r = hashmap_replace(d->positive_by_key, rr->key, answer);
 351         if (r < 0)
 352                 return log_error_errno(r, "Failed to add answer to trust anchor: %m");
 353
 354         old_answer = dns_answer_unref(old_answer);
 355         answer = NULL;
 356
 357         return 0;
 358 }
 359
 360 static int dns_trust_anchor_load_negative(DnsTrustAnchor *d, const char *path, unsigned line, const char *s) {
 361         _cleanup_free_ char *domain = NULL;
 362         const char *p = s;
 363         int r;
 364
 365         assert(d);
 366         assert(line);
 367
 368         r = extract_first_word(&p, &domain, NULL, EXTRACT_QUOTES);
 369         if (r < 0)
 370                 return log_warning_errno(r, "Unable to parse line %s:%u: %m", path, line);
 371
 372         if (!dns_name_is_valid(domain)) {
 373                 log_warning("Domain name %s is invalid, at line %s:%u, ignoring line.", domain, path, line);
 374                 return -EINVAL;
 375         }
 376
 377         if (!isempty(p)) {
 378                 log_warning("Trailing garbage at line %s:%u, ignoring line.", path, line);
 379                 return -EINVAL;
 380         }
 381
 382         r = set_ensure_allocated(&d->negative_by_name, &dns_name_hash_ops);
 383         if (r < 0)
 384                 return log_oom();
 385
 386         r = set_put(d->negative_by_name, domain);
 387         if (r < 0)
 388                 return log_oom();
 389         if (r > 0)
 390                 domain = NULL;
 391
 392         return 0;
 393 }
 394
 395 static int dns_trust_anchor_load_files(
 396                 DnsTrustAnchor *d,
 397                 const char *suffix,
 398                 int (*loader)(DnsTrustAnchor *d, const char *path, unsigned n, const char *line)) {
 399
 400         _cleanup_strv_free_ char **files = NULL;
 401         char **f;
 402         int r;
 403
 404         assert(d);
 405         assert(suffix);
 406         assert(loader);
 407
 408         r = conf_files_list_nulstr(&files, suffix, NULL, trust_anchor_dirs);
 409         if (r < 0)
 410                 return log_error_errno(r, "Failed to enumerate %s trust anchor files: %m", suffix);
 411
 412         STRV_FOREACH(f, files) {
 413                 _cleanup_fclose_ FILE *g = NULL;
 414                 char line[LINE_MAX];
 415                 unsigned n = 0;
 416
 417                 g = fopen(*f, "r");
 418                 if (!g) {
 419                         if (errno == ENOENT)
 420                                 continue;
 421
 422                         log_warning_errno(errno, "Failed to open %s: %m", *f);
 423                         continue;
 424                 }
 425
 426                 FOREACH_LINE(line, g, log_warning_errno(errno, "Failed to read %s, ignoring: %m", *f)) {
 427                         char *l;
 428
 429                         n++;
 430
 431                         l = strstrip(line);
 432                         if (isempty(l))
 433                                 continue;
 434
 435                         if (*l == ';')
 436                                 continue;
 437
 438                         (void) loader(d, *f, n, l);
 439                 }
 440         }
 441
 442         return 0;
 443 }
 444
 445 static int domain_name_cmp(const void *a, const void *b) {
 446         char **x = (char**) a, **y = (char**) b;
 447
 448         return dns_name_compare_func(*x, *y);
 449 }
 450
 451 static int dns_trust_anchor_dump(DnsTrustAnchor *d) {
 452         DnsAnswer *a;
 453         Iterator i;
 454
 455         assert(d);
 456
 457         if (hashmap_isempty(d->positive_by_key))
 458                 log_info("No positive trust anchors defined.");
 459         else {
 460                 log_info("Positive Trust Anchors:");
 461                 HASHMAP_FOREACH(a, d->positive_by_key, i) {
 462                         DnsResourceRecord *rr;
 463
 464                         DNS_ANSWER_FOREACH(rr, a)
 465                                 log_info("%s", dns_resource_record_to_string(rr));
 466                 }
 467         }
 468
 469         if (set_isempty(d->negative_by_name))
 470                 log_info("No negative trust anchors defined.");
 471         else {
 472                 _cleanup_free_ char **l = NULL, *j = NULL;
 473
 474                 l = set_get_strv(d->negative_by_name);
 475                 if (!l)
 476                         return log_oom();
 477
 478                 qsort_safe(l, set_size(d->negative_by_name), sizeof(char*), domain_name_cmp);
 479
 480                 j = strv_join(l, " ");
 481                 if (!j)
 482                         return log_oom();
 483
 484                 log_info("Negative trust anchors: %s", j);
 485         }
 486
 487         return 0;
 488 }
 489
 490 int dns_trust_anchor_load(DnsTrustAnchor *d) {
 491         int r;
 492
 493         assert(d);
 494
 495         /* If loading things from disk fails, we don't consider this fatal */
 496         (void) dns_trust_anchor_load_files(d, ".positive", dns_trust_anchor_load_positive);
 497         (void) dns_trust_anchor_load_files(d, ".negative", dns_trust_anchor_load_negative);
 498
 499         /* However, if the built-in DS fails, then we have a problem. */
 500         r = dns_trust_anchor_add_builtin_positive(d);
 501         if (r < 0)
 502                 return log_error_errno(r, "Failed to add built-in positive trust anchor: %m");
 503
 504         r = dns_trust_anchor_add_builtin_negative(d);
 505         if (r < 0)
 506                 return log_error_errno(r, "Failed to add built-in negative trust anchor: %m");
 507
 508         dns_trust_anchor_dump(d);
 509
 510         return 0;
 511 }
 512
 513 void dns_trust_anchor_flush(DnsTrustAnchor *d) {
 514         DnsAnswer *a;
 515         DnsResourceRecord *rr;
 516
 517         assert(d);
 518
 519         while ((a = hashmap_steal_first(d->positive_by_key)))
 520                 dns_answer_unref(a);
 521         d->positive_by_key = hashmap_free(d->positive_by_key);
 522
 523         while ((rr = set_steal_first(d->revoked_by_rr)))
 524                 dns_resource_record_unref(rr);
 525         d->revoked_by_rr = set_free(d->revoked_by_rr);
 526
 527         d->negative_by_name = set_free_free(d->negative_by_name);
 528 }
 529
 530 int dns_trust_anchor_lookup_positive(DnsTrustAnchor *d, const DnsResourceKey *key, DnsAnswer **ret) {
 531         DnsAnswer *a;
 532
 533         assert(d);
 534         assert(key);
 535         assert(ret);
 536
 537         /* We only serve DS and DNSKEY RRs. */
 538         if (!IN_SET(key->type, DNS_TYPE_DS, DNS_TYPE_DNSKEY))
 539                 return 0;
 540
 541         a = hashmap_get(d->positive_by_key, key);
 542         if (!a)
 543                 return 0;
 544
 545         *ret = dns_answer_ref(a);
 546         return 1;
 547 }
 548
 549 int dns_trust_anchor_lookup_negative(DnsTrustAnchor *d, const char *name) {
 550         int r;
 551
 552         assert(d);
 553         assert(name);
 554
 555         for (;;) {
 556                 /* If the domain is listed as-is in the NTA database, then that counts */
 557                 if (set_contains(d->negative_by_name, name))
 558                         return true;
 559
 560                 /* If the domain isn't listed as NTA, but is listed as positive trust anchor, then that counts. See RFC
 561                  * 7646, section 1.1 */
 562                 if (hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_DS, name)))
 563                         return false;
 564
 565                 if (hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_KEY, name)))
 566                         return false;
 567
 568                 /* And now, let's look at the parent, and check that too */
 569                 r = dns_name_parent(&name);
 570                 if (r < 0)
 571                         return r;
 572                 if (r == 0)
 573                         break;
 574         }
 575
 576         return false;
 577 }
 578
 579 static int dns_trust_anchor_revoked_put(DnsTrustAnchor *d, DnsResourceRecord *rr) {
 580         int r;
 581
 582         assert(d);
 583
 584         r = set_ensure_allocated(&d->revoked_by_rr, &dns_resource_record_hash_ops);
 585         if (r < 0)
 586                 return r;
 587
 588         r = set_put(d->revoked_by_rr, rr);
 589         if (r < 0)
 590                 return r;
 591         if (r > 0)
 592                 dns_resource_record_ref(rr);
 593
 594         return r;
 595 }
 596
 597 static int dns_trust_anchor_remove_revoked(DnsTrustAnchor *d, DnsResourceRecord *rr) {
 598         _cleanup_(dns_answer_unrefp) DnsAnswer *new_answer = NULL;
 599         DnsAnswer *old_answer;
 600         int r;
 601
 602         /* Remember that this is a revoked trust anchor RR */
 603         r = dns_trust_anchor_revoked_put(d, rr);
 604         if (r < 0)
 605                 return r;
 606
 607         /* Remove this from the positive trust anchor */
 608         old_answer = hashmap_get(d->positive_by_key, rr->key);
 609         if (!old_answer)
 610                 return 0;
 611
 612         new_answer = dns_answer_ref(old_answer);
 613
 614         r = dns_answer_remove_by_rr(&new_answer, rr);
 615         if (r <= 0)
 616                 return r;
 617
 618         /* We found the key! Warn the user */
 619         log_struct(LOG_WARNING,
 620                    "MESSAGE_ID=" SD_MESSAGE_DNSSEC_TRUST_ANCHOR_REVOKED_STR,
 621                    LOG_MESSAGE("DNSSEC Trust anchor %s has been revoked. Please update the trust anchor, or upgrade your operating system."), strna(dns_resource_record_to_string(rr)),
 622                    "TRUST_ANCHOR=%s", dns_resource_record_to_string(rr),
 623                    NULL);
 624
 625         if (dns_answer_size(new_answer) <= 0) {
 626                 assert_se(hashmap_remove(d->positive_by_key, rr->key) == old_answer);
 627                 dns_answer_unref(old_answer);
 628                 return 1;
 629         }
 630
 631         r = hashmap_replace(d->positive_by_key, new_answer->items[0].rr->key, new_answer);
 632         if (r < 0)
 633                 return r;
 634
 635         new_answer = NULL;
 636         dns_answer_unref(old_answer);
 637         return 1;
 638 }
 639
 640 static int dns_trust_anchor_check_revoked_one(DnsTrustAnchor *d, DnsResourceRecord *revoked_dnskey) {
 641         DnsAnswer *a;
 642         int r;
 643
 644         assert(d);
 645         assert(revoked_dnskey);
 646         assert(revoked_dnskey->key->type == DNS_TYPE_DNSKEY);
 647         assert(revoked_dnskey->dnskey.flags & DNSKEY_FLAG_REVOKE);
 648
 649         a = hashmap_get(d->positive_by_key, revoked_dnskey->key);
 650         if (a) {
 651                 DnsResourceRecord *anchor;
 652
 653                 /* First, look for the precise DNSKEY in our trust anchor database */
 654
 655                 DNS_ANSWER_FOREACH(anchor, a) {
 656
 657                         if (anchor->dnskey.protocol != revoked_dnskey->dnskey.protocol)
 658                                 continue;
 659
 660                         if (anchor->dnskey.algorithm != revoked_dnskey->dnskey.algorithm)
 661                                 continue;
 662
 663                         if (anchor->dnskey.key_size != revoked_dnskey->dnskey.key_size)
 664                                 continue;
 665
 666                         /* Note that we allow the REVOKE bit to be
 667                          * different! It will be set in the revoked
 668                          * key, but unset in our version of it */
 669                         if (((anchor->dnskey.flags ^ revoked_dnskey->dnskey.flags) | DNSKEY_FLAG_REVOKE) != DNSKEY_FLAG_REVOKE)
 670                                 continue;
 671
 672                         if (memcmp(anchor->dnskey.key, revoked_dnskey->dnskey.key, anchor->dnskey.key_size) != 0)
 673                                 continue;
 674
 675                         dns_trust_anchor_remove_revoked(d, anchor);
 676                         break;
 677                 }
 678         }
 679
 680         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)));
 681         if (a) {
 682                 DnsResourceRecord *anchor;
 683
 684                 /* Second, look for DS RRs matching this DNSKEY in our trust anchor database */
 685
 686                 DNS_ANSWER_FOREACH(anchor, a) {
 687
 688                         /* We set mask_revoke to true here, since our
 689                          * DS fingerprint will be the one of the
 690                          * unrevoked DNSKEY, but the one we got passed
 691                          * here has the bit set. */
 692                         r = dnssec_verify_dnskey_by_ds(revoked_dnskey, anchor, true);
 693                         if (r < 0)
 694                                 return r;
 695                         if (r == 0)
 696                                 continue;
 697
 698                         dns_trust_anchor_remove_revoked(d, anchor);
 699                         break;
 700                 }
 701         }
 702
 703         return 0;
 704 }
 705
 706 int dns_trust_anchor_check_revoked(DnsTrustAnchor *d, DnsResourceRecord *dnskey, DnsAnswer *rrs) {
 707         DnsResourceRecord *rrsig;
 708         int r;
 709
 710         assert(d);
 711         assert(dnskey);
 712
 713         /* Looks if "dnskey" is a self-signed RR that has been revoked
 714          * and matches one of our trust anchor entries. If so, removes
 715          * it from the trust anchor and returns > 0. */
 716
 717         if (dnskey->key->type != DNS_TYPE_DNSKEY)
 718                 return 0;
 719
 720         /* Is this DNSKEY revoked? */
 721         if ((dnskey->dnskey.flags & DNSKEY_FLAG_REVOKE) == 0)
 722                 return 0;
 723
 724         /* Could this be interesting to us at all? If not,
 725          * there's no point in looking for and verifying a
 726          * self-signed RRSIG. */
 727         if (!dns_trust_anchor_knows_domain_positive(d, dns_resource_key_name(dnskey->key)))
 728                 return 0;
 729
 730         /* Look for a self-signed RRSIG in the other rrs belonging to this DNSKEY */
 731         DNS_ANSWER_FOREACH(rrsig, rrs) {
 732                 DnssecResult result;
 733
 734                 if (rrsig->key->type != DNS_TYPE_RRSIG)
 735                         continue;
 736
 737                 r = dnssec_rrsig_match_dnskey(rrsig, dnskey, true);
 738                 if (r < 0)
 739                         return r;
 740                 if (r == 0)
 741                         continue;
 742
 743                 r = dnssec_verify_rrset(rrs, dnskey->key, rrsig, dnskey, USEC_INFINITY, &result);
 744                 if (r < 0)
 745                         return r;
 746                 if (result != DNSSEC_VALIDATED)
 747                         continue;
 748
 749                 /* Bingo! This is a revoked self-signed DNSKEY. Let's
 750                  * see if this precise one exists in our trust anchor
 751                  * database, too. */
 752                 r = dns_trust_anchor_check_revoked_one(d, dnskey);
 753                 if (r < 0)
 754                         return r;
 755
 756                 return 1;
 757         }
 758
 759         return 0;
 760 }
 761
 762 int dns_trust_anchor_is_revoked(DnsTrustAnchor *d, DnsResourceRecord *rr) {
 763         assert(d);
 764
 765         if (!IN_SET(rr->key->type, DNS_TYPE_DS, DNS_TYPE_DNSKEY))
 766                 return 0;
 767
 768         return set_contains(d->revoked_by_rr, rr);
 769 }