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

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   This file is part of systemd.
   4
   5   Copyright 2015 Lennart Poettering
   6 ***/
   7
   8 #include "sd-messages.h"
   9
  10 #include "alloc-util.h"
  11 #include "conf-files.h"
  12 #include "def.h"
  13 #include "dns-domain.h"
  14 #include "fd-util.h"
  15 #include "fileio.h"
  16 #include "hexdecoct.h"
  17 #include "parse-util.h"
  18 #include "resolved-dns-trust-anchor.h"
  19 #include "resolved-dns-dnssec.h"
  20 #include "set.h"
  21 #include "string-util.h"
  22 #include "strv.h"
  23
  24 static const char trust_anchor_dirs[] = CONF_PATHS_NULSTR("dnssec-trust-anchors.d");
  25
  26 /* The first DS RR from https://data.iana.org/root-anchors/root-anchors.xml, retrieved December 2015 */
  27 static const uint8_t root_digest1[] =
  28         { 0x49, 0xAA, 0xC1, 0x1D, 0x7B, 0x6F, 0x64, 0x46, 0x70, 0x2E, 0x54, 0xA1, 0x60, 0x73, 0x71, 0x60,
  29           0x7A, 0x1A, 0x41, 0x85, 0x52, 0x00, 0xFD, 0x2C, 0xE1, 0xCD, 0xDE, 0x32, 0xF2, 0x4E, 0x8F, 0xB5 };
  30
  31 /* The second DS RR from https://data.iana.org/root-anchors/root-anchors.xml, retrieved February 2017 */
  32 static const uint8_t root_digest2[] =
  33         { 0xE0, 0x6D, 0x44, 0xB8, 0x0B, 0x8F, 0x1D, 0x39, 0xA9, 0x5C, 0x0B, 0x0D, 0x7C, 0x65, 0xD0, 0x84,
  34           0x58, 0xE8, 0x80, 0x40, 0x9B, 0xBC, 0x68, 0x34, 0x57, 0x10, 0x42, 0x37, 0xC7, 0xF8, 0xEC, 0x8D };
  35
  36 static bool dns_trust_anchor_knows_domain_positive(DnsTrustAnchor *d, const char *name) {
  37         assert(d);
  38
  39         /* Returns true if there's an entry for the specified domain
  40          * name in our trust anchor */
  41
  42         return
  43                 hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_DNSKEY, name)) ||
  44                 hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_DS, name));
  45 }
  46
  47 static int add_root_ksk(
  48                 DnsAnswer *answer,
  49                 DnsResourceKey *key,
  50                 uint16_t key_tag,
  51                 uint8_t algorithm,
  52                 uint8_t digest_type,
  53                 const void *digest,
  54                 size_t digest_size) {
  55
  56         _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
  57         int r;
  58
  59         rr = dns_resource_record_new(key);
  60         if (!rr)
  61                 return -ENOMEM;
  62
  63         rr->ds.key_tag = key_tag;
  64         rr->ds.algorithm = algorithm;
  65         rr->ds.digest_type = digest_type;
  66         rr->ds.digest_size = digest_size;
  67         rr->ds.digest = memdup(digest, rr->ds.digest_size);
  68         if (!rr->ds.digest)
  69                 return  -ENOMEM;
  70
  71         r = dns_answer_add(answer, rr, 0, DNS_ANSWER_AUTHENTICATED);
  72         if (r < 0)
  73                 return r;
  74
  75         return 0;
  76 }
  77
  78 static int dns_trust_anchor_add_builtin_positive(DnsTrustAnchor *d) {
  79         _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
  80         _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
  81         int r;
  82
  83         assert(d);
  84
  85         r = hashmap_ensure_allocated(&d->positive_by_key, &dns_resource_key_hash_ops);
  86         if (r < 0)
  87                 return r;
  88
  89         /* Only add the built-in trust anchor if there's neither a DS nor a DNSKEY defined for the root domain. That
  90          * way users have an easy way to override the root domain DS/DNSKEY data. */
  91         if (dns_trust_anchor_knows_domain_positive(d, "."))
  92                 return 0;
  93
  94         key = dns_resource_key_new(DNS_CLASS_IN, DNS_TYPE_DS, "");
  95         if (!key)
  96                 return -ENOMEM;
  97
  98         answer = dns_answer_new(2);
  99         if (!answer)
 100                 return -ENOMEM;
 101
 102         /* Add the two RRs from https://data.iana.org/root-anchors/root-anchors.xml */
 103         r = add_root_ksk(answer, key, 19036, DNSSEC_ALGORITHM_RSASHA256, DNSSEC_DIGEST_SHA256, root_digest1, sizeof(root_digest1));
 104         if (r < 0)
 105                 return r;
 106
 107         r = add_root_ksk(answer, key, 20326, DNSSEC_ALGORITHM_RSASHA256, DNSSEC_DIGEST_SHA256, root_digest2, sizeof(root_digest2));
 108         if (r < 0)
 109                 return r;
 110
 111         r = hashmap_put(d->positive_by_key, key, answer);
 112         if (r < 0)
 113                 return r;
 114
 115         answer = NULL;
 116         return 0;
 117 }
 118
 119 static int dns_trust_anchor_add_builtin_negative(DnsTrustAnchor *d) {
 120
 121         static const char private_domains[] =
 122                 /* RFC 6761 says that .test is a special domain for
 123                  * testing and not to be installed in the root zone */
 124                 "test\0"
 125
 126                 /* RFC 6761 says that these reverse IP lookup ranges
 127                  * are for private addresses, and hence should not
 128                  * show up in the root zone */
 129                 "10.in-addr.arpa\0"
 130                 "16.172.in-addr.arpa\0"
 131                 "17.172.in-addr.arpa\0"
 132                 "18.172.in-addr.arpa\0"
 133                 "19.172.in-addr.arpa\0"
 134                 "20.172.in-addr.arpa\0"
 135                 "21.172.in-addr.arpa\0"
 136                 "22.172.in-addr.arpa\0"
 137                 "23.172.in-addr.arpa\0"
 138                 "24.172.in-addr.arpa\0"
 139                 "25.172.in-addr.arpa\0"
 140                 "26.172.in-addr.arpa\0"
 141                 "27.172.in-addr.arpa\0"
 142                 "28.172.in-addr.arpa\0"
 143                 "29.172.in-addr.arpa\0"
 144                 "30.172.in-addr.arpa\0"
 145                 "31.172.in-addr.arpa\0"
 146                 "168.192.in-addr.arpa\0"
 147
 148                 /* The same, but for IPv6. */
 149                 "d.f.ip6.arpa\0"
 150
 151                 /* RFC 6762 reserves the .local domain for Multicast
 152                  * DNS, it hence cannot appear in the root zone. (Note
 153                  * that we by default do not route .local traffic to
 154                  * DNS anyway, except when a configured search domain
 155                  * suggests so.) */
 156                 "local\0"
 157
 158                 /* These two are well known, popular private zone
 159                  * TLDs, that are blocked from delegation, according
 160                  * to:
 161                  * http://icannwiki.com/Name_Collision#NGPC_Resolution
 162                  *
 163                  * There's also ongoing work on making this official
 164                  * in an RRC:
 165                  * https://www.ietf.org/archive/id/draft-chapin-additional-reserved-tlds-02.txt */
 166                 "home\0"
 167                 "corp\0"
 168
 169                 /* The following four TLDs are suggested for private
 170                  * zones in RFC 6762, Appendix G, and are hence very
 171                  * unlikely to be made official TLDs any day soon */
 172                 "lan\0"
 173                 "intranet\0"
 174                 "internal\0"
 175                 "private\0";
 176
 177         const char *name;
 178         int r;
 179
 180         assert(d);
 181
 182         /* Only add the built-in trust anchor if there's no negative
 183          * trust anchor defined at all. This enables easy overriding
 184          * of negative trust anchors. */
 185
 186         if (set_size(d->negative_by_name) > 0)
 187                 return 0;
 188
 189         r = set_ensure_allocated(&d->negative_by_name, &dns_name_hash_ops);
 190         if (r < 0)
 191                 return r;
 192
 193         /* We add a couple of domains as default negative trust
 194          * anchors, where it's very unlikely they will be installed in
 195          * the root zone. If they exist they must be private, and thus
 196          * unsigned. */
 197
 198         NULSTR_FOREACH(name, private_domains) {
 199
 200                 if (dns_trust_anchor_knows_domain_positive(d, name))
 201                         continue;
 202
 203                 r = set_put_strdup(d->negative_by_name, name);
 204                 if (r < 0)
 205                         return r;
 206         }
 207
 208         return 0;
 209 }
 210
 211 static int dns_trust_anchor_load_positive(DnsTrustAnchor *d, const char *path, unsigned line, const char *s) {
 212         _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
 213         _cleanup_free_ char *domain = NULL, *class = NULL, *type = NULL;
 214         _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
 215         DnsAnswer *old_answer = NULL;
 216         const char *p = s;
 217         int r;
 218
 219         assert(d);
 220         assert(line);
 221
 222         r = extract_first_word(&p, &domain, NULL, EXTRACT_QUOTES);
 223         if (r < 0)
 224                 return log_warning_errno(r, "Unable to parse domain in line %s:%u: %m", path, line);
 225
 226         if (!dns_name_is_valid(domain)) {
 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, *digest = 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, &digest, 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 != 4) {
 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                 r = unhexmem(digest, strlen(digest), &dd, &l);
 278                 if (r < 0) {
 279                         log_warning("Failed to parse DS digest %s on line %s:%u", digest, path, line);
 280                         return -EINVAL;
 281                 }
 282
 283                 rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_DS, domain);
 284                 if (!rr)
 285                         return log_oom();
 286
 287                 rr->ds.key_tag = kt;
 288                 rr->ds.algorithm = a;
 289                 rr->ds.digest_type = dt;
 290                 rr->ds.digest_size = l;
 291                 rr->ds.digest = TAKE_PTR(dd);
 292
 293         } else if (strcaseeq(type, "DNSKEY")) {
 294                 _cleanup_free_ char *flags = NULL, *protocol = NULL, *algorithm = NULL, *key = NULL;
 295                 _cleanup_free_ void *k = NULL;
 296                 uint16_t f;
 297                 size_t l;
 298                 int a;
 299
 300                 r = extract_many_words(&p, NULL, 0, &flags, &protocol, &algorithm, &key, NULL);
 301                 if (r < 0)
 302                         return log_warning_errno(r, "Failed to parse DNSKEY parameters on line %s:%u: %m", path, line);
 303                 if (r != 4) {
 304                         log_warning("Missing DNSKEY parameters on line %s:%u", path, line);
 305                         return -EINVAL;
 306                 }
 307
 308                 if (!streq(protocol, "3")) {
 309                         log_warning("DNSKEY Protocol is not 3 on line %s:%u", path, line);
 310                         return -EINVAL;
 311                 }
 312
 313                 r = safe_atou16(flags, &f);
 314                 if (r < 0)
 315                         return log_warning_errno(r, "Failed to parse DNSKEY flags field %s on line %s:%u", flags, path, line);
 316                 if ((f & DNSKEY_FLAG_ZONE_KEY) == 0) {
 317                         log_warning("DNSKEY lacks zone key bit set on line %s:%u", path, line);
 318                         return -EINVAL;
 319                 }
 320                 if ((f & DNSKEY_FLAG_REVOKE)) {
 321                         log_warning("DNSKEY is already revoked on line %s:%u", path, line);
 322                         return -EINVAL;
 323                 }
 324
 325                 a = dnssec_algorithm_from_string(algorithm);
 326                 if (a < 0) {
 327                         log_warning("Failed to parse DNSKEY algorithm %s on line %s:%u", algorithm, path, line);
 328                         return -EINVAL;
 329                 }
 330
 331                 r = unbase64mem(key, strlen(key), &k, &l);
 332                 if (r < 0)
 333                         return log_warning_errno(r, "Failed to parse DNSKEY key data %s on line %s:%u", key, path, line);
 334
 335                 rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_DNSKEY, domain);
 336                 if (!rr)
 337                         return log_oom();
 338
 339                 rr->dnskey.flags = f;
 340                 rr->dnskey.protocol = 3;
 341                 rr->dnskey.algorithm = a;
 342                 rr->dnskey.key_size = l;
 343                 rr->dnskey.key = TAKE_PTR(k);
 344
 345         } else {
 346                 log_warning("RR type %s is not supported, ignoring line %s:%u.", type, path, line);
 347                 return -EINVAL;
 348         }
 349
 350         if (!isempty(p)) {
 351                 log_warning("Trailing garbage on line %s:%u, ignoring line.", path, line);
 352                 return -EINVAL;
 353         }
 354
 355         r = hashmap_ensure_allocated(&d->positive_by_key, &dns_resource_key_hash_ops);
 356         if (r < 0)
 357                 return log_oom();
 358
 359         old_answer = hashmap_get(d->positive_by_key, rr->key);
 360         answer = dns_answer_ref(old_answer);
 361
 362         r = dns_answer_add_extend(&answer, rr, 0, DNS_ANSWER_AUTHENTICATED);
 363         if (r < 0)
 364                 return log_error_errno(r, "Failed to add trust anchor RR: %m");
 365
 366         r = hashmap_replace(d->positive_by_key, rr->key, answer);
 367         if (r < 0)
 368                 return log_error_errno(r, "Failed to add answer to trust anchor: %m");
 369
 370         old_answer = dns_answer_unref(old_answer);
 371         answer = NULL;
 372
 373         return 0;
 374 }
 375
 376 static int dns_trust_anchor_load_negative(DnsTrustAnchor *d, const char *path, unsigned line, const char *s) {
 377         _cleanup_free_ char *domain = NULL;
 378         const char *p = s;
 379         int r;
 380
 381         assert(d);
 382         assert(line);
 383
 384         r = extract_first_word(&p, &domain, NULL, EXTRACT_QUOTES);
 385         if (r < 0)
 386                 return log_warning_errno(r, "Unable to parse line %s:%u: %m", path, line);
 387
 388         if (!dns_name_is_valid(domain)) {
 389                 log_warning("Domain name %s is invalid, at line %s:%u, ignoring line.", domain, path, line);
 390                 return -EINVAL;
 391         }
 392
 393         if (!isempty(p)) {
 394                 log_warning("Trailing garbage at line %s:%u, ignoring line.", path, line);
 395                 return -EINVAL;
 396         }
 397
 398         r = set_ensure_allocated(&d->negative_by_name, &dns_name_hash_ops);
 399         if (r < 0)
 400                 return log_oom();
 401
 402         r = set_put(d->negative_by_name, domain);
 403         if (r < 0)
 404                 return log_oom();
 405         if (r > 0)
 406                 domain = NULL;
 407
 408         return 0;
 409 }
 410
 411 static int dns_trust_anchor_load_files(
 412                 DnsTrustAnchor *d,
 413                 const char *suffix,
 414                 int (*loader)(DnsTrustAnchor *d, const char *path, unsigned n, const char *line)) {
 415
 416         _cleanup_strv_free_ char **files = NULL;
 417         char **f;
 418         int r;
 419
 420         assert(d);
 421         assert(suffix);
 422         assert(loader);
 423
 424         r = conf_files_list_nulstr(&files, suffix, NULL, 0, trust_anchor_dirs);
 425         if (r < 0)
 426                 return log_error_errno(r, "Failed to enumerate %s trust anchor files: %m", suffix);
 427
 428         STRV_FOREACH(f, files) {
 429                 _cleanup_fclose_ FILE *g = NULL;
 430                 char line[LINE_MAX];
 431                 unsigned n = 0;
 432
 433                 g = fopen(*f, "r");
 434                 if (!g) {
 435                         if (errno == ENOENT)
 436                                 continue;
 437
 438                         log_warning_errno(errno, "Failed to open %s: %m", *f);
 439                         continue;
 440                 }
 441
 442                 FOREACH_LINE(line, g, log_warning_errno(errno, "Failed to read %s, ignoring: %m", *f)) {
 443                         char *l;
 444
 445                         n++;
 446
 447                         l = strstrip(line);
 448                         if (isempty(l))
 449                                 continue;
 450
 451                         if (*l == ';')
 452                                 continue;
 453
 454                         (void) loader(d, *f, n, l);
 455                 }
 456         }
 457
 458         return 0;
 459 }
 460
 461 static int domain_name_cmp(const void *a, const void *b) {
 462         char **x = (char**) a, **y = (char**) b;
 463
 464         return dns_name_compare_func(*x, *y);
 465 }
 466
 467 static int dns_trust_anchor_dump(DnsTrustAnchor *d) {
 468         DnsAnswer *a;
 469         Iterator i;
 470
 471         assert(d);
 472
 473         if (hashmap_isempty(d->positive_by_key))
 474                 log_info("No positive trust anchors defined.");
 475         else {
 476                 log_info("Positive Trust Anchors:");
 477                 HASHMAP_FOREACH(a, d->positive_by_key, i) {
 478                         DnsResourceRecord *rr;
 479
 480                         DNS_ANSWER_FOREACH(rr, a)
 481                                 log_info("%s", dns_resource_record_to_string(rr));
 482                 }
 483         }
 484
 485         if (set_isempty(d->negative_by_name))
 486                 log_info("No negative trust anchors defined.");
 487         else {
 488                 _cleanup_free_ char **l = NULL, *j = NULL;
 489
 490                 l = set_get_strv(d->negative_by_name);
 491                 if (!l)
 492                         return log_oom();
 493
 494                 qsort_safe(l, set_size(d->negative_by_name), sizeof(char*), domain_name_cmp);
 495
 496                 j = strv_join(l, " ");
 497                 if (!j)
 498                         return log_oom();
 499
 500                 log_info("Negative trust anchors: %s", j);
 501         }
 502
 503         return 0;
 504 }
 505
 506 int dns_trust_anchor_load(DnsTrustAnchor *d) {
 507         int r;
 508
 509         assert(d);
 510
 511         /* If loading things from disk fails, we don't consider this fatal */
 512         (void) dns_trust_anchor_load_files(d, ".positive", dns_trust_anchor_load_positive);
 513         (void) dns_trust_anchor_load_files(d, ".negative", dns_trust_anchor_load_negative);
 514
 515         /* However, if the built-in DS fails, then we have a problem. */
 516         r = dns_trust_anchor_add_builtin_positive(d);
 517         if (r < 0)
 518                 return log_error_errno(r, "Failed to add built-in positive trust anchor: %m");
 519
 520         r = dns_trust_anchor_add_builtin_negative(d);
 521         if (r < 0)
 522                 return log_error_errno(r, "Failed to add built-in negative trust anchor: %m");
 523
 524         dns_trust_anchor_dump(d);
 525
 526         return 0;
 527 }
 528
 529 void dns_trust_anchor_flush(DnsTrustAnchor *d) {
 530         assert(d);
 531
 532         d->positive_by_key = hashmap_free_with_destructor(d->positive_by_key, dns_answer_unref);
 533         d->revoked_by_rr = set_free_with_destructor(d->revoked_by_rr, dns_resource_record_unref);
 534         d->negative_by_name = set_free_free(d->negative_by_name);
 535 }
 536
 537 int dns_trust_anchor_lookup_positive(DnsTrustAnchor *d, const DnsResourceKey *key, DnsAnswer **ret) {
 538         DnsAnswer *a;
 539
 540         assert(d);
 541         assert(key);
 542         assert(ret);
 543
 544         /* We only serve DS and DNSKEY RRs. */
 545         if (!IN_SET(key->type, DNS_TYPE_DS, DNS_TYPE_DNSKEY))
 546                 return 0;
 547
 548         a = hashmap_get(d->positive_by_key, key);
 549         if (!a)
 550                 return 0;
 551
 552         *ret = dns_answer_ref(a);
 553         return 1;
 554 }
 555
 556 int dns_trust_anchor_lookup_negative(DnsTrustAnchor *d, const char *name) {
 557         int r;
 558
 559         assert(d);
 560         assert(name);
 561
 562         for (;;) {
 563                 /* If the domain is listed as-is in the NTA database, then that counts */
 564                 if (set_contains(d->negative_by_name, name))
 565                         return true;
 566
 567                 /* If the domain isn't listed as NTA, but is listed as positive trust anchor, then that counts. See RFC
 568                  * 7646, section 1.1 */
 569                 if (hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_DS, name)))
 570                         return false;
 571
 572                 if (hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_KEY, name)))
 573                         return false;
 574
 575                 /* And now, let's look at the parent, and check that too */
 576                 r = dns_name_parent(&name);
 577                 if (r < 0)
 578                         return r;
 579                 if (r == 0)
 580                         break;
 581         }
 582
 583         return false;
 584 }
 585
 586 static int dns_trust_anchor_revoked_put(DnsTrustAnchor *d, DnsResourceRecord *rr) {
 587         int r;
 588
 589         assert(d);
 590
 591         r = set_ensure_allocated(&d->revoked_by_rr, &dns_resource_record_hash_ops);
 592         if (r < 0)
 593                 return r;
 594
 595         r = set_put(d->revoked_by_rr, 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         int r;
 608
 609         /* Remember that this is a revoked trust anchor RR */
 610         r = dns_trust_anchor_revoked_put(d, rr);
 611         if (r < 0)
 612                 return r;
 613
 614         /* Remove this from the positive trust anchor */
 615         old_answer = hashmap_get(d->positive_by_key, rr->key);
 616         if (!old_answer)
 617                 return 0;
 618
 619         new_answer = dns_answer_ref(old_answer);
 620
 621         r = dns_answer_remove_by_rr(&new_answer, rr);
 622         if (r <= 0)
 623                 return r;
 624
 625         /* We found the key! Warn the user */
 626         log_struct(LOG_WARNING,
 627                    "MESSAGE_ID=" SD_MESSAGE_DNSSEC_TRUST_ANCHOR_REVOKED_STR,
 628                    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)),
 629                    "TRUST_ANCHOR=%s", dns_resource_record_to_string(rr),
 630                    NULL);
 631
 632         if (dns_answer_size(new_answer) <= 0) {
 633                 assert_se(hashmap_remove(d->positive_by_key, rr->key) == old_answer);
 634                 dns_answer_unref(old_answer);
 635                 return 1;
 636         }
 637
 638         r = hashmap_replace(d->positive_by_key, new_answer->items[0].rr->key, new_answer);
 639         if (r < 0)
 640                 return r;
 641
 642         new_answer = NULL;
 643         dns_answer_unref(old_answer);
 644         return 1;
 645 }
 646
 647 static int dns_trust_anchor_check_revoked_one(DnsTrustAnchor *d, DnsResourceRecord *revoked_dnskey) {
 648         DnsAnswer *a;
 649         int r;
 650
 651         assert(d);
 652         assert(revoked_dnskey);
 653         assert(revoked_dnskey->key->type == DNS_TYPE_DNSKEY);
 654         assert(revoked_dnskey->dnskey.flags & DNSKEY_FLAG_REVOKE);
 655
 656         a = hashmap_get(d->positive_by_key, revoked_dnskey->key);
 657         if (a) {
 658                 DnsResourceRecord *anchor;
 659
 660                 /* First, look for the precise DNSKEY in our trust anchor database */
 661
 662                 DNS_ANSWER_FOREACH(anchor, a) {
 663
 664                         if (anchor->dnskey.protocol != revoked_dnskey->dnskey.protocol)
 665                                 continue;
 666
 667                         if (anchor->dnskey.algorithm != revoked_dnskey->dnskey.algorithm)
 668                                 continue;
 669
 670                         if (anchor->dnskey.key_size != revoked_dnskey->dnskey.key_size)
 671                                 continue;
 672
 673                         /* Note that we allow the REVOKE bit to be
 674                          * different! It will be set in the revoked
 675                          * key, but unset in our version of it */
 676                         if (((anchor->dnskey.flags ^ revoked_dnskey->dnskey.flags) | DNSKEY_FLAG_REVOKE) != DNSKEY_FLAG_REVOKE)
 677                                 continue;
 678
 679                         if (memcmp(anchor->dnskey.key, revoked_dnskey->dnskey.key, anchor->dnskey.key_size) != 0)
 680                                 continue;
 681
 682                         dns_trust_anchor_remove_revoked(d, anchor);
 683                         break;
 684                 }
 685         }
 686
 687         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)));
 688         if (a) {
 689                 DnsResourceRecord *anchor;
 690
 691                 /* Second, look for DS RRs matching this DNSKEY in our trust anchor database */
 692
 693                 DNS_ANSWER_FOREACH(anchor, a) {
 694
 695                         /* We set mask_revoke to true here, since our
 696                          * DS fingerprint will be the one of the
 697                          * unrevoked DNSKEY, but the one we got passed
 698                          * here has the bit set. */
 699                         r = dnssec_verify_dnskey_by_ds(revoked_dnskey, anchor, true);
 700                         if (r < 0)
 701                                 return r;
 702                         if (r == 0)
 703                                 continue;
 704
 705                         dns_trust_anchor_remove_revoked(d, anchor);
 706                         break;
 707                 }
 708         }
 709
 710         return 0;
 711 }
 712
 713 int dns_trust_anchor_check_revoked(DnsTrustAnchor *d, DnsResourceRecord *dnskey, DnsAnswer *rrs) {
 714         DnsResourceRecord *rrsig;
 715         int r;
 716
 717         assert(d);
 718         assert(dnskey);
 719
 720         /* Looks if "dnskey" is a self-signed RR that has been revoked
 721          * and matches one of our trust anchor entries. If so, removes
 722          * it from the trust anchor and returns > 0. */
 723
 724         if (dnskey->key->type != DNS_TYPE_DNSKEY)
 725                 return 0;
 726
 727         /* Is this DNSKEY revoked? */
 728         if ((dnskey->dnskey.flags & DNSKEY_FLAG_REVOKE) == 0)
 729                 return 0;
 730
 731         /* Could this be interesting to us at all? If not,
 732          * there's no point in looking for and verifying a
 733          * self-signed RRSIG. */
 734         if (!dns_trust_anchor_knows_domain_positive(d, dns_resource_key_name(dnskey->key)))
 735                 return 0;
 736
 737         /* Look for a self-signed RRSIG in the other rrs belonging to this DNSKEY */
 738         DNS_ANSWER_FOREACH(rrsig, rrs) {
 739                 DnssecResult result;
 740
 741                 if (rrsig->key->type != DNS_TYPE_RRSIG)
 742                         continue;
 743
 744                 r = dnssec_rrsig_match_dnskey(rrsig, dnskey, true);
 745                 if (r < 0)
 746                         return r;
 747                 if (r == 0)
 748                         continue;
 749
 750                 r = dnssec_verify_rrset(rrs, dnskey->key, rrsig, dnskey, USEC_INFINITY, &result);
 751                 if (r < 0)
 752                         return r;
 753                 if (result != DNSSEC_VALIDATED)
 754                         continue;
 755
 756                 /* Bingo! This is a revoked self-signed DNSKEY. Let's
 757                  * see if this precise one exists in our trust anchor
 758                  * database, too. */
 759                 r = dns_trust_anchor_check_revoked_one(d, dnskey);
 760                 if (r < 0)
 761                         return r;
 762
 763                 return 1;
 764         }
 765
 766         return 0;
 767 }
 768
 769 int dns_trust_anchor_is_revoked(DnsTrustAnchor *d, DnsResourceRecord *rr) {
 770         assert(d);
 771
 772         if (!IN_SET(rr->key->type, DNS_TYPE_DS, DNS_TYPE_DNSKEY))
 773                 return 0;
 774
 775         return set_contains(d->revoked_by_rr, rr);
 776 }