summaryrefslogtreecommitdiff
path: root/src/resolve/resolved-dns-trust-anchor.c
blob: 69e363733025ecfe4423908dfe787a98985d11c9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
/* SPDX-License-Identifier: LGPL-2.1+ */
/***
  This file is part of systemd.

  Copyright 2015 Lennart Poettering
***/

#include "sd-messages.h"

#include "alloc-util.h"
#include "conf-files.h"
#include "def.h"
#include "dns-domain.h"
#include "fd-util.h"
#include "fileio.h"
#include "hexdecoct.h"
#include "parse-util.h"
#include "resolved-dns-trust-anchor.h"
#include "resolved-dns-dnssec.h"
#include "set.h"
#include "string-util.h"
#include "strv.h"

static const char trust_anchor_dirs[] = CONF_PATHS_NULSTR("dnssec-trust-anchors.d");

/* The first DS RR from https://data.iana.org/root-anchors/root-anchors.xml, retrieved December 2015 */
static const uint8_t root_digest1[] =
        { 0x49, 0xAA, 0xC1, 0x1D, 0x7B, 0x6F, 0x64, 0x46, 0x70, 0x2E, 0x54, 0xA1, 0x60, 0x73, 0x71, 0x60,
          0x7A, 0x1A, 0x41, 0x85, 0x52, 0x00, 0xFD, 0x2C, 0xE1, 0xCD, 0xDE, 0x32, 0xF2, 0x4E, 0x8F, 0xB5 };

/* The second DS RR from https://data.iana.org/root-anchors/root-anchors.xml, retrieved February 2017 */
static const uint8_t root_digest2[] =
        { 0xE0, 0x6D, 0x44, 0xB8, 0x0B, 0x8F, 0x1D, 0x39, 0xA9, 0x5C, 0x0B, 0x0D, 0x7C, 0x65, 0xD0, 0x84,
          0x58, 0xE8, 0x80, 0x40, 0x9B, 0xBC, 0x68, 0x34, 0x57, 0x10, 0x42, 0x37, 0xC7, 0xF8, 0xEC, 0x8D };

static bool dns_trust_anchor_knows_domain_positive(DnsTrustAnchor *d, const char *name) {
        assert(d);

        /* Returns true if there's an entry for the specified domain
         * name in our trust anchor */

        return
                hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_DNSKEY, name)) ||
                hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_DS, name));
}

static int add_root_ksk(
                DnsAnswer *answer,
                DnsResourceKey *key,
                uint16_t key_tag,
                uint8_t algorithm,
                uint8_t digest_type,
                const void *digest,
                size_t digest_size) {

        _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
        int r;

        rr = dns_resource_record_new(key);
        if (!rr)
                return -ENOMEM;

        rr->ds.key_tag = key_tag;
        rr->ds.algorithm = algorithm;
        rr->ds.digest_type = digest_type;
        rr->ds.digest_size = digest_size;
        rr->ds.digest = memdup(digest, rr->ds.digest_size);
        if (!rr->ds.digest)
                return  -ENOMEM;

        r = dns_answer_add(answer, rr, 0, DNS_ANSWER_AUTHENTICATED);
        if (r < 0)
                return r;

        return 0;
}

static int dns_trust_anchor_add_builtin_positive(DnsTrustAnchor *d) {
        _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
        _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
        int r;

        assert(d);

        r = hashmap_ensure_allocated(&d->positive_by_key, &dns_resource_key_hash_ops);
        if (r < 0)
                return r;

        /* Only add the built-in trust anchor if there's neither a DS nor a DNSKEY defined for the root domain. That
         * way users have an easy way to override the root domain DS/DNSKEY data. */
        if (dns_trust_anchor_knows_domain_positive(d, "."))
                return 0;

        key = dns_resource_key_new(DNS_CLASS_IN, DNS_TYPE_DS, "");
        if (!key)
                return -ENOMEM;

        answer = dns_answer_new(2);
        if (!answer)
                return -ENOMEM;

        /* Add the two RRs from https://data.iana.org/root-anchors/root-anchors.xml */
        r = add_root_ksk(answer, key, 19036, DNSSEC_ALGORITHM_RSASHA256, DNSSEC_DIGEST_SHA256, root_digest1, sizeof(root_digest1));
        if (r < 0)
                return r;

        r = add_root_ksk(answer, key, 20326, DNSSEC_ALGORITHM_RSASHA256, DNSSEC_DIGEST_SHA256, root_digest2, sizeof(root_digest2));
        if (r < 0)
                return r;

        r = hashmap_put(d->positive_by_key, key, answer);
        if (r < 0)
                return r;

        answer = NULL;
        return 0;
}

static int dns_trust_anchor_add_builtin_negative(DnsTrustAnchor *d) {

        static const char private_domains[] =
                /* RFC 6761 says that .test is a special domain for
                 * testing and not to be installed in the root zone */
                "test\0"

                /* RFC 6761 says that these reverse IP lookup ranges
                 * are for private addresses, and hence should not
                 * show up in the root zone */
                "10.in-addr.arpa\0"
                "16.172.in-addr.arpa\0"
                "17.172.in-addr.arpa\0"
                "18.172.in-addr.arpa\0"
                "19.172.in-addr.arpa\0"
                "20.172.in-addr.arpa\0"
                "21.172.in-addr.arpa\0"
                "22.172.in-addr.arpa\0"
                "23.172.in-addr.arpa\0"
                "24.172.in-addr.arpa\0"
                "25.172.in-addr.arpa\0"
                "26.172.in-addr.arpa\0"
                "27.172.in-addr.arpa\0"
                "28.172.in-addr.arpa\0"
                "29.172.in-addr.arpa\0"
                "30.172.in-addr.arpa\0"
                "31.172.in-addr.arpa\0"
                "168.192.in-addr.arpa\0"

                /* The same, but for IPv6. */
                "d.f.ip6.arpa\0"

                /* RFC 6762 reserves the .local domain for Multicast
                 * DNS, it hence cannot appear in the root zone. (Note
                 * that we by default do not route .local traffic to
                 * DNS anyway, except when a configured search domain
                 * suggests so.) */
                "local\0"

                /* These two are well known, popular private zone
                 * TLDs, that are blocked from delegation, according
                 * to:
                 * http://icannwiki.com/Name_Collision#NGPC_Resolution
                 *
                 * There's also ongoing work on making this official
                 * in an RRC:
                 * https://www.ietf.org/archive/id/draft-chapin-additional-reserved-tlds-02.txt */
                "home\0"
                "corp\0"

                /* The following four TLDs are suggested for private
                 * zones in RFC 6762, Appendix G, and are hence very
                 * unlikely to be made official TLDs any day soon */
                "lan\0"
                "intranet\0"
                "internal\0"
                "private\0";

        const char *name;
        int r;

        assert(d);

        /* Only add the built-in trust anchor if there's no negative
         * trust anchor defined at all. This enables easy overriding
         * of negative trust anchors. */

        if (set_size(d->negative_by_name) > 0)
                return 0;

        r = set_ensure_allocated(&d->negative_by_name, &dns_name_hash_ops);
        if (r < 0)
                return r;

        /* We add a couple of domains as default negative trust
         * anchors, where it's very unlikely they will be installed in
         * the root zone. If they exist they must be private, and thus
         * unsigned. */

        NULSTR_FOREACH(name, private_domains) {

                if (dns_trust_anchor_knows_domain_positive(d, name))
                        continue;

                r = set_put_strdup(d->negative_by_name, name);
                if (r < 0)
                        return r;
        }

        return 0;
}

static int dns_trust_anchor_load_positive(DnsTrustAnchor *d, const char *path, unsigned line, const char *s) {
        _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
        _cleanup_free_ char *domain = NULL, *class = NULL, *type = NULL;
        _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
        DnsAnswer *old_answer = NULL;
        const char *p = s;
        int r;

        assert(d);
        assert(line);

        r = extract_first_word(&p, &domain, NULL, EXTRACT_QUOTES);
        if (r < 0)
                return log_warning_errno(r, "Unable to parse domain in line %s:%u: %m", path, line);

        if (!dns_name_is_valid(domain)) {
                log_warning("Domain name %s is invalid, at line %s:%u, ignoring line.", domain, path, line);
                return -EINVAL;
        }

        r = extract_many_words(&p, NULL, 0, &class, &type, NULL);
        if (r < 0)
                return log_warning_errno(r, "Unable to parse class and type in line %s:%u: %m", path, line);
        if (r != 2) {
                log_warning("Missing class or type in line %s:%u", path, line);
                return -EINVAL;
        }

        if (!strcaseeq(class, "IN")) {
                log_warning("RR class %s is not supported, ignoring line %s:%u.", class, path, line);
                return -EINVAL;
        }

        if (strcaseeq(type, "DS")) {
                _cleanup_free_ char *key_tag = NULL, *algorithm = NULL, *digest_type = NULL;
                _cleanup_free_ void *dd = NULL;
                uint16_t kt;
                int a, dt;
                size_t l;

                r = extract_many_words(&p, NULL, 0, &key_tag, &algorithm, &digest_type, NULL);
                if (r < 0) {
                        log_warning_errno(r, "Failed to parse DS parameters on line %s:%u: %m", path, line);
                        return -EINVAL;
                }
                if (r != 3) {
                        log_warning("Missing DS parameters on line %s:%u", path, line);
                        return -EINVAL;
                }

                r = safe_atou16(key_tag, &kt);
                if (r < 0)
                        return log_warning_errno(r, "Failed to parse DS key tag %s on line %s:%u: %m", key_tag, path, line);

                a = dnssec_algorithm_from_string(algorithm);
                if (a < 0) {
                        log_warning("Failed to parse DS algorithm %s on line %s:%u", algorithm, path, line);
                        return -EINVAL;
                }

                dt = dnssec_digest_from_string(digest_type);
                if (dt < 0) {
                        log_warning("Failed to parse DS digest type %s on line %s:%u", digest_type, path, line);
                        return -EINVAL;
                }

                if (isempty(p)) {
                        log_warning("Missing DS digest on line %s:%u", path, line);
                        return -EINVAL;
                }

                r = unhexmem(p, strlen(p), &dd, &l);
                if (r < 0) {
                        log_warning("Failed to parse DS digest %s on line %s:%u", p, path, line);
                        return -EINVAL;
                }

                rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_DS, domain);
                if (!rr)
                        return log_oom();

                rr->ds.key_tag = kt;
                rr->ds.algorithm = a;
                rr->ds.digest_type = dt;
                rr->ds.digest_size = l;
                rr->ds.digest = TAKE_PTR(dd);

        } else if (strcaseeq(type, "DNSKEY")) {
                _cleanup_free_ char *flags = NULL, *protocol = NULL, *algorithm = NULL;
                _cleanup_free_ void *k = NULL;
                uint16_t f;
                size_t l;
                int a;

                r = extract_many_words(&p, NULL, 0, &flags, &protocol, &algorithm, NULL);
                if (r < 0)
                        return log_warning_errno(r, "Failed to parse DNSKEY parameters on line %s:%u: %m", path, line);
                if (r != 3) {
                        log_warning("Missing DNSKEY parameters on line %s:%u", path, line);
                        return -EINVAL;
                }

                if (!streq(protocol, "3")) {
                        log_warning("DNSKEY Protocol is not 3 on line %s:%u", path, line);
                        return -EINVAL;
                }

                r = safe_atou16(flags, &f);
                if (r < 0)
                        return log_warning_errno(r, "Failed to parse DNSKEY flags field %s on line %s:%u", flags, path, line);
                if ((f & DNSKEY_FLAG_ZONE_KEY) == 0) {
                        log_warning("DNSKEY lacks zone key bit set on line %s:%u", path, line);
                        return -EINVAL;
                }
                if ((f & DNSKEY_FLAG_REVOKE)) {
                        log_warning("DNSKEY is already revoked on line %s:%u", path, line);
                        return -EINVAL;
                }

                a = dnssec_algorithm_from_string(algorithm);
                if (a < 0) {
                        log_warning("Failed to parse DNSKEY algorithm %s on line %s:%u", algorithm, path, line);
                        return -EINVAL;
                }

                if (isempty(p)) {
                        log_warning("Missing DNSKEY key on line %s:%u", path, line);
                        return -EINVAL;
                }

                r = unbase64mem(p, strlen(p), &k, &l);
                if (r < 0)
                        return log_warning_errno(r, "Failed to parse DNSKEY key data %s on line %s:%u", p, path, line);

                rr = dns_resource_record_new_full(DNS_CLASS_IN, DNS_TYPE_DNSKEY, domain);
                if (!rr)
                        return log_oom();

                rr->dnskey.flags = f;
                rr->dnskey.protocol = 3;
                rr->dnskey.algorithm = a;
                rr->dnskey.key_size = l;
                rr->dnskey.key = TAKE_PTR(k);

        } else {
                log_warning("RR type %s is not supported, ignoring line %s:%u.", type, path, line);
                return -EINVAL;
        }

        r = hashmap_ensure_allocated(&d->positive_by_key, &dns_resource_key_hash_ops);
        if (r < 0)
                return log_oom();

        old_answer = hashmap_get(d->positive_by_key, rr->key);
        answer = dns_answer_ref(old_answer);

        r = dns_answer_add_extend(&answer, rr, 0, DNS_ANSWER_AUTHENTICATED);
        if (r < 0)
                return log_error_errno(r, "Failed to add trust anchor RR: %m");

        r = hashmap_replace(d->positive_by_key, rr->key, answer);
        if (r < 0)
                return log_error_errno(r, "Failed to add answer to trust anchor: %m");

        old_answer = dns_answer_unref(old_answer);
        answer = NULL;

        return 0;
}

static int dns_trust_anchor_load_negative(DnsTrustAnchor *d, const char *path, unsigned line, const char *s) {
        _cleanup_free_ char *domain = NULL;
        const char *p = s;
        int r;

        assert(d);
        assert(line);

        r = extract_first_word(&p, &domain, NULL, EXTRACT_QUOTES);
        if (r < 0)
                return log_warning_errno(r, "Unable to parse line %s:%u: %m", path, line);

        if (!dns_name_is_valid(domain)) {
                log_warning("Domain name %s is invalid, at line %s:%u, ignoring line.", domain, path, line);
                return -EINVAL;
        }

        if (!isempty(p)) {
                log_warning("Trailing garbage at line %s:%u, ignoring line.", path, line);
                return -EINVAL;
        }

        r = set_ensure_allocated(&d->negative_by_name, &dns_name_hash_ops);
        if (r < 0)
                return log_oom();

        r = set_put(d->negative_by_name, domain);
        if (r < 0)
                return log_oom();
        if (r > 0)
                domain = NULL;

        return 0;
}

static int dns_trust_anchor_load_files(
                DnsTrustAnchor *d,
                const char *suffix,
                int (*loader)(DnsTrustAnchor *d, const char *path, unsigned n, const char *line)) {

        _cleanup_strv_free_ char **files = NULL;
        char **f;
        int r;

        assert(d);
        assert(suffix);
        assert(loader);

        r = conf_files_list_nulstr(&files, suffix, NULL, 0, trust_anchor_dirs);
        if (r < 0)
                return log_error_errno(r, "Failed to enumerate %s trust anchor files: %m", suffix);

        STRV_FOREACH(f, files) {
                _cleanup_fclose_ FILE *g = NULL;
                char line[LINE_MAX];
                unsigned n = 0;

                g = fopen(*f, "r");
                if (!g) {
                        if (errno == ENOENT)
                                continue;

                        log_warning_errno(errno, "Failed to open %s: %m", *f);
                        continue;
                }

                FOREACH_LINE(line, g, log_warning_errno(errno, "Failed to read %s, ignoring: %m", *f)) {
                        char *l;

                        n++;

                        l = strstrip(line);
                        if (isempty(l))
                                continue;

                        if (*l == ';')
                                continue;

                        (void) loader(d, *f, n, l);
                }
        }

        return 0;
}

static int domain_name_cmp(const void *a, const void *b) {
        char **x = (char**) a, **y = (char**) b;

        return dns_name_compare_func(*x, *y);
}

static int dns_trust_anchor_dump(DnsTrustAnchor *d) {
        DnsAnswer *a;
        Iterator i;

        assert(d);

        if (hashmap_isempty(d->positive_by_key))
                log_info("No positive trust anchors defined.");
        else {
                log_info("Positive Trust Anchors:");
                HASHMAP_FOREACH(a, d->positive_by_key, i) {
                        DnsResourceRecord *rr;

                        DNS_ANSWER_FOREACH(rr, a)
                                log_info("%s", dns_resource_record_to_string(rr));
                }
        }

        if (set_isempty(d->negative_by_name))
                log_info("No negative trust anchors defined.");
        else {
                _cleanup_free_ char **l = NULL, *j = NULL;

                l = set_get_strv(d->negative_by_name);
                if (!l)
                        return log_oom();

                qsort_safe(l, set_size(d->negative_by_name), sizeof(char*), domain_name_cmp);

                j = strv_join(l, " ");
                if (!j)
                        return log_oom();

                log_info("Negative trust anchors: %s", j);
        }

        return 0;
}

int dns_trust_anchor_load(DnsTrustAnchor *d) {
        int r;

        assert(d);

        /* If loading things from disk fails, we don't consider this fatal */
        (void) dns_trust_anchor_load_files(d, ".positive", dns_trust_anchor_load_positive);
        (void) dns_trust_anchor_load_files(d, ".negative", dns_trust_anchor_load_negative);

        /* However, if the built-in DS fails, then we have a problem. */
        r = dns_trust_anchor_add_builtin_positive(d);
        if (r < 0)
                return log_error_errno(r, "Failed to add built-in positive trust anchor: %m");

        r = dns_trust_anchor_add_builtin_negative(d);
        if (r < 0)
                return log_error_errno(r, "Failed to add built-in negative trust anchor: %m");

        dns_trust_anchor_dump(d);

        return 0;
}

void dns_trust_anchor_flush(DnsTrustAnchor *d) {
        assert(d);

        d->positive_by_key = hashmap_free_with_destructor(d->positive_by_key, dns_answer_unref);
        d->revoked_by_rr = set_free_with_destructor(d->revoked_by_rr, dns_resource_record_unref);
        d->negative_by_name = set_free_free(d->negative_by_name);
}

int dns_trust_anchor_lookup_positive(DnsTrustAnchor *d, const DnsResourceKey *key, DnsAnswer **ret) {
        DnsAnswer *a;

        assert(d);
        assert(key);
        assert(ret);

        /* We only serve DS and DNSKEY RRs. */
        if (!IN_SET(key->type, DNS_TYPE_DS, DNS_TYPE_DNSKEY))
                return 0;

        a = hashmap_get(d->positive_by_key, key);
        if (!a)
                return 0;

        *ret = dns_answer_ref(a);
        return 1;
}

int dns_trust_anchor_lookup_negative(DnsTrustAnchor *d, const char *name) {
        int r;

        assert(d);
        assert(name);

        for (;;) {
                /* If the domain is listed as-is in the NTA database, then that counts */
                if (set_contains(d->negative_by_name, name))
                        return true;

                /* If the domain isn't listed as NTA, but is listed as positive trust anchor, then that counts. See RFC
                 * 7646, section 1.1 */
                if (hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_DS, name)))
                        return false;

                if (hashmap_contains(d->positive_by_key, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN, DNS_TYPE_KEY, name)))
                        return false;

                /* And now, let's look at the parent, and check that too */
                r = dns_name_parent(&name);
                if (r < 0)
                        return r;
                if (r == 0)
                        break;
        }

        return false;
}

static int dns_trust_anchor_revoked_put(DnsTrustAnchor *d, DnsResourceRecord *rr) {
        int r;

        assert(d);

        r = set_ensure_allocated(&d->revoked_by_rr, &dns_resource_record_hash_ops);
        if (r < 0)
                return r;

        r = set_put(d->revoked_by_rr, rr);
        if (r < 0)
                return r;
        if (r > 0)
                dns_resource_record_ref(rr);

        return r;
}

static int dns_trust_anchor_remove_revoked(DnsTrustAnchor *d, DnsResourceRecord *rr) {
        _cleanup_(dns_answer_unrefp) DnsAnswer *new_answer = NULL;
        DnsAnswer *old_answer;
        int r;

        /* Remember that this is a revoked trust anchor RR */
        r = dns_trust_anchor_revoked_put(d, rr);
        if (r < 0)
                return r;

        /* Remove this from the positive trust anchor */
        old_answer = hashmap_get(d->positive_by_key, rr->key);
        if (!old_answer)
                return 0;

        new_answer = dns_answer_ref(old_answer);

        r = dns_answer_remove_by_rr(&new_answer, rr);
        if (r <= 0)
                return r;

        /* We found the key! Warn the user */
        log_struct(LOG_WARNING,
                   "MESSAGE_ID=" SD_MESSAGE_DNSSEC_TRUST_ANCHOR_REVOKED_STR,
                   LOG_MESSAGE("DNSSEC trust anchor %s has been revoked.\n"
                               "Please update the trust anchor, or upgrade your operating system.",
                               strna(dns_resource_record_to_string(rr))),
                   "TRUST_ANCHOR=%s", dns_resource_record_to_string(rr));

        if (dns_answer_size(new_answer) <= 0) {
                assert_se(hashmap_remove(d->positive_by_key, rr->key) == old_answer);
                dns_answer_unref(old_answer);
                return 1;
        }

        r = hashmap_replace(d->positive_by_key, new_answer->items[0].rr->key, new_answer);
        if (r < 0)
                return r;

        new_answer = NULL;
        dns_answer_unref(old_answer);
        return 1;
}

static int dns_trust_anchor_check_revoked_one(DnsTrustAnchor *d, DnsResourceRecord *revoked_dnskey) {
        DnsAnswer *a;
        int r;

        assert(d);
        assert(revoked_dnskey);
        assert(revoked_dnskey->key->type == DNS_TYPE_DNSKEY);
        assert(revoked_dnskey->dnskey.flags & DNSKEY_FLAG_REVOKE);

        a = hashmap_get(d->positive_by_key, revoked_dnskey->key);
        if (a) {
                DnsResourceRecord *anchor;

                /* First, look for the precise DNSKEY in our trust anchor database */

                DNS_ANSWER_FOREACH(anchor, a) {

                        if (anchor->dnskey.protocol != revoked_dnskey->dnskey.protocol)
                                continue;

                        if (anchor->dnskey.algorithm != revoked_dnskey->dnskey.algorithm)
                                continue;

                        if (anchor->dnskey.key_size != revoked_dnskey->dnskey.key_size)
                                continue;

                        /* Note that we allow the REVOKE bit to be
                         * different! It will be set in the revoked
                         * key, but unset in our version of it */
                        if (((anchor->dnskey.flags ^ revoked_dnskey->dnskey.flags) | DNSKEY_FLAG_REVOKE) != DNSKEY_FLAG_REVOKE)
                                continue;

                        if (memcmp(anchor->dnskey.key, revoked_dnskey->dnskey.key, anchor->dnskey.key_size) != 0)
                                continue;

                        dns_trust_anchor_remove_revoked(d, anchor);
                        break;
                }
        }

        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)));
        if (a) {
                DnsResourceRecord *anchor;

                /* Second, look for DS RRs matching this DNSKEY in our trust anchor database */

                DNS_ANSWER_FOREACH(anchor, a) {

                        /* We set mask_revoke to true here, since our
                         * DS fingerprint will be the one of the
                         * unrevoked DNSKEY, but the one we got passed
                         * here has the bit set. */
                        r = dnssec_verify_dnskey_by_ds(revoked_dnskey, anchor, true);
                        if (r < 0)
                                return r;
                        if (r == 0)
                                continue;

                        dns_trust_anchor_remove_revoked(d, anchor);
                        break;
                }
        }

        return 0;
}

int dns_trust_anchor_check_revoked(DnsTrustAnchor *d, DnsResourceRecord *dnskey, DnsAnswer *rrs) {
        DnsResourceRecord *rrsig;
        int r;

        assert(d);
        assert(dnskey);

        /* Looks if "dnskey" is a self-signed RR that has been revoked
         * and matches one of our trust anchor entries. If so, removes
         * it from the trust anchor and returns > 0. */

        if (dnskey->key->type != DNS_TYPE_DNSKEY)
                return 0;

        /* Is this DNSKEY revoked? */
        if ((dnskey->dnskey.flags & DNSKEY_FLAG_REVOKE) == 0)
                return 0;

        /* Could this be interesting to us at all? If not,
         * there's no point in looking for and verifying a
         * self-signed RRSIG. */
        if (!dns_trust_anchor_knows_domain_positive(d, dns_resource_key_name(dnskey->key)))
                return 0;

        /* Look for a self-signed RRSIG in the other rrs belonging to this DNSKEY */
        DNS_ANSWER_FOREACH(rrsig, rrs) {
                DnssecResult result;

                if (rrsig->key->type != DNS_TYPE_RRSIG)
                        continue;

                r = dnssec_rrsig_match_dnskey(rrsig, dnskey, true);
                if (r < 0)
                        return r;
                if (r == 0)
                        continue;

                r = dnssec_verify_rrset(rrs, dnskey->key, rrsig, dnskey, USEC_INFINITY, &result);
                if (r < 0)
                        return r;
                if (result != DNSSEC_VALIDATED)
                        continue;

                /* Bingo! This is a revoked self-signed DNSKEY. Let's
                 * see if this precise one exists in our trust anchor
                 * database, too. */
                r = dns_trust_anchor_check_revoked_one(d, dnskey);
                if (r < 0)
                        return r;

                return 1;
        }

        return 0;
}

int dns_trust_anchor_is_revoked(DnsTrustAnchor *d, DnsResourceRecord *rr) {
        assert(d);

        if (!IN_SET(rr->key->type, DNS_TYPE_DS, DNS_TYPE_DNSKEY))
                return 0;

        return set_contains(d->revoked_by_rr, rr);
}