1 /* SPDX-License-Identifier: LGPL-2.1+ */
3 This file is part of systemd.
5 Copyright 2015 Lennart Poettering
8 #include "sd-messages.h"
10 #include "alloc-util.h"
11 #include "conf-files.h"
13 #include "dns-domain.h"
16 #include "hexdecoct.h"
17 #include "parse-util.h"
18 #include "resolved-dns-trust-anchor.h"
19 #include "resolved-dns-dnssec.h"
21 #include "string-util.h"
24 static const char trust_anchor_dirs
[] = CONF_PATHS_NULSTR("dnssec-trust-anchors.d");
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 };
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 };
36 static bool dns_trust_anchor_knows_domain_positive(DnsTrustAnchor
*d
, const char *name
) {
39 /* Returns true if there's an entry for the specified domain
40 * name in our trust anchor */
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
));
47 static int add_root_ksk(
56 _cleanup_(dns_resource_record_unrefp
) DnsResourceRecord
*rr
= NULL
;
59 rr
= dns_resource_record_new(key
);
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
);
71 r
= dns_answer_add(answer
, rr
, 0, DNS_ANSWER_AUTHENTICATED
);
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
;
85 r
= hashmap_ensure_allocated(&d
->positive_by_key
, &dns_resource_key_hash_ops
);
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
, "."))
94 key
= dns_resource_key_new(DNS_CLASS_IN
, DNS_TYPE_DS
, "");
98 answer
= dns_answer_new(2);
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
));
107 r
= add_root_ksk(answer
, key
, 20326, DNSSEC_ALGORITHM_RSASHA256
, DNSSEC_DIGEST_SHA256
, root_digest2
, sizeof(root_digest2
));
111 r
= hashmap_put(d
->positive_by_key
, key
, answer
);
119 static int dns_trust_anchor_add_builtin_negative(DnsTrustAnchor
*d
) {
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 */
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 */
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"
148 /* The same, but for IPv6. */
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
158 /* These two are well known, popular private zone
159 * TLDs, that are blocked from delegation, according
161 * http://icannwiki.com/Name_Collision#NGPC_Resolution
163 * There's also ongoing work on making this official
165 * https://www.ietf.org/archive/id/draft-chapin-additional-reserved-tlds-02.txt */
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 */
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. */
186 if (set_size(d
->negative_by_name
) > 0)
189 r
= set_ensure_allocated(&d
->negative_by_name
, &dns_name_hash_ops
);
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
198 NULSTR_FOREACH(name
, private_domains
) {
200 if (dns_trust_anchor_knows_domain_positive(d
, name
))
203 r
= set_put_strdup(d
->negative_by_name
, name
);
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
;
222 r
= extract_first_word(&p
, &domain
, NULL
, EXTRACT_QUOTES
);
224 return log_warning_errno(r
, "Unable to parse domain in line %s:%u: %m", path
, line
);
226 if (!dns_name_is_valid(domain
)) {
227 log_warning("Domain name %s is invalid, at line %s:%u, ignoring line.", domain
, path
, line
);
231 r
= extract_many_words(&p
, NULL
, 0, &class, &type
, NULL
);
233 return log_warning_errno(r
, "Unable to parse class and type in line %s:%u: %m", path
, line
);
235 log_warning("Missing class or type in line %s:%u", path
, line
);
239 if (!strcaseeq(class, "IN")) {
240 log_warning("RR class %s is not supported, ignoring line %s:%u.", class, path
, line
);
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
;
251 r
= extract_many_words(&p
, NULL
, 0, &key_tag
, &algorithm
, &digest_type
, &digest
, NULL
);
253 log_warning_errno(r
, "Failed to parse DS parameters on line %s:%u: %m", path
, line
);
257 log_warning("Missing DS parameters on line %s:%u", path
, line
);
261 r
= safe_atou16(key_tag
, &kt
);
263 return log_warning_errno(r
, "Failed to parse DS key tag %s on line %s:%u: %m", key_tag
, path
, line
);
265 a
= dnssec_algorithm_from_string(algorithm
);
267 log_warning("Failed to parse DS algorithm %s on line %s:%u", algorithm
, path
, line
);
271 dt
= dnssec_digest_from_string(digest_type
);
273 log_warning("Failed to parse DS digest type %s on line %s:%u", digest_type
, path
, line
);
277 r
= unhexmem(digest
, strlen(digest
), &dd
, &l
);
279 log_warning("Failed to parse DS digest %s on line %s:%u", digest
, path
, line
);
283 rr
= dns_resource_record_new_full(DNS_CLASS_IN
, DNS_TYPE_DS
, domain
);
288 rr
->ds
.algorithm
= a
;
289 rr
->ds
.digest_type
= dt
;
290 rr
->ds
.digest_size
= l
;
291 rr
->ds
.digest
= TAKE_PTR(dd
);
293 } else if (strcaseeq(type
, "DNSKEY")) {
294 _cleanup_free_
char *flags
= NULL
, *protocol
= NULL
, *algorithm
= NULL
, *key
= NULL
;
295 _cleanup_free_
void *k
= NULL
;
300 r
= extract_many_words(&p
, NULL
, 0, &flags
, &protocol
, &algorithm
, &key
, NULL
);
302 return log_warning_errno(r
, "Failed to parse DNSKEY parameters on line %s:%u: %m", path
, line
);
304 log_warning("Missing DNSKEY parameters on line %s:%u", path
, line
);
308 if (!streq(protocol
, "3")) {
309 log_warning("DNSKEY Protocol is not 3 on line %s:%u", path
, line
);
313 r
= safe_atou16(flags
, &f
);
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
);
320 if ((f
& DNSKEY_FLAG_REVOKE
)) {
321 log_warning("DNSKEY is already revoked on line %s:%u", path
, line
);
325 a
= dnssec_algorithm_from_string(algorithm
);
327 log_warning("Failed to parse DNSKEY algorithm %s on line %s:%u", algorithm
, path
, line
);
331 r
= unbase64mem(key
, strlen(key
), &k
, &l
);
333 return log_warning_errno(r
, "Failed to parse DNSKEY key data %s on line %s:%u", key
, path
, line
);
335 rr
= dns_resource_record_new_full(DNS_CLASS_IN
, DNS_TYPE_DNSKEY
, domain
);
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
);
346 log_warning("RR type %s is not supported, ignoring line %s:%u.", type
, path
, line
);
351 log_warning("Trailing garbage on line %s:%u, ignoring line.", path
, line
);
355 r
= hashmap_ensure_allocated(&d
->positive_by_key
, &dns_resource_key_hash_ops
);
359 old_answer
= hashmap_get(d
->positive_by_key
, rr
->key
);
360 answer
= dns_answer_ref(old_answer
);
362 r
= dns_answer_add_extend(&answer
, rr
, 0, DNS_ANSWER_AUTHENTICATED
);
364 return log_error_errno(r
, "Failed to add trust anchor RR: %m");
366 r
= hashmap_replace(d
->positive_by_key
, rr
->key
, answer
);
368 return log_error_errno(r
, "Failed to add answer to trust anchor: %m");
370 old_answer
= dns_answer_unref(old_answer
);
376 static int dns_trust_anchor_load_negative(DnsTrustAnchor
*d
, const char *path
, unsigned line
, const char *s
) {
377 _cleanup_free_
char *domain
= NULL
;
384 r
= extract_first_word(&p
, &domain
, NULL
, EXTRACT_QUOTES
);
386 return log_warning_errno(r
, "Unable to parse line %s:%u: %m", path
, line
);
388 if (!dns_name_is_valid(domain
)) {
389 log_warning("Domain name %s is invalid, at line %s:%u, ignoring line.", domain
, path
, line
);
394 log_warning("Trailing garbage at line %s:%u, ignoring line.", path
, line
);
398 r
= set_ensure_allocated(&d
->negative_by_name
, &dns_name_hash_ops
);
402 r
= set_put(d
->negative_by_name
, domain
);
411 static int dns_trust_anchor_load_files(
414 int (*loader
)(DnsTrustAnchor
*d
, const char *path
, unsigned n
, const char *line
)) {
416 _cleanup_strv_free_
char **files
= NULL
;
424 r
= conf_files_list_nulstr(&files
, suffix
, NULL
, 0, trust_anchor_dirs
);
426 return log_error_errno(r
, "Failed to enumerate %s trust anchor files: %m", suffix
);
428 STRV_FOREACH(f
, files
) {
429 _cleanup_fclose_
FILE *g
= NULL
;
438 log_warning_errno(errno
, "Failed to open %s: %m", *f
);
442 FOREACH_LINE(line
, g
, log_warning_errno(errno
, "Failed to read %s, ignoring: %m", *f
)) {
454 (void) loader(d
, *f
, n
, l
);
461 static int domain_name_cmp(const void *a
, const void *b
) {
462 char **x
= (char**) a
, **y
= (char**) b
;
464 return dns_name_compare_func(*x
, *y
);
467 static int dns_trust_anchor_dump(DnsTrustAnchor
*d
) {
473 if (hashmap_isempty(d
->positive_by_key
))
474 log_info("No positive trust anchors defined.");
476 log_info("Positive Trust Anchors:");
477 HASHMAP_FOREACH(a
, d
->positive_by_key
, i
) {
478 DnsResourceRecord
*rr
;
480 DNS_ANSWER_FOREACH(rr
, a
)
481 log_info("%s", dns_resource_record_to_string(rr
));
485 if (set_isempty(d
->negative_by_name
))
486 log_info("No negative trust anchors defined.");
488 _cleanup_free_
char **l
= NULL
, *j
= NULL
;
490 l
= set_get_strv(d
->negative_by_name
);
494 qsort_safe(l
, set_size(d
->negative_by_name
), sizeof(char*), domain_name_cmp
);
496 j
= strv_join(l
, " ");
500 log_info("Negative trust anchors: %s", j
);
506 int dns_trust_anchor_load(DnsTrustAnchor
*d
) {
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
);
515 /* However, if the built-in DS fails, then we have a problem. */
516 r
= dns_trust_anchor_add_builtin_positive(d
);
518 return log_error_errno(r
, "Failed to add built-in positive trust anchor: %m");
520 r
= dns_trust_anchor_add_builtin_negative(d
);
522 return log_error_errno(r
, "Failed to add built-in negative trust anchor: %m");
524 dns_trust_anchor_dump(d
);
529 void dns_trust_anchor_flush(DnsTrustAnchor
*d
) {
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
);
537 int dns_trust_anchor_lookup_positive(DnsTrustAnchor
*d
, const DnsResourceKey
*key
, DnsAnswer
**ret
) {
544 /* We only serve DS and DNSKEY RRs. */
545 if (!IN_SET(key
->type
, DNS_TYPE_DS
, DNS_TYPE_DNSKEY
))
548 a
= hashmap_get(d
->positive_by_key
, key
);
552 *ret
= dns_answer_ref(a
);
556 int dns_trust_anchor_lookup_negative(DnsTrustAnchor
*d
, const char *name
) {
563 /* If the domain is listed as-is in the NTA database, then that counts */
564 if (set_contains(d
->negative_by_name
, name
))
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
)))
572 if (hashmap_contains(d
->positive_by_key
, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN
, DNS_TYPE_KEY
, name
)))
575 /* And now, let's look at the parent, and check that too */
576 r
= dns_name_parent(&name
);
586 static int dns_trust_anchor_revoked_put(DnsTrustAnchor
*d
, DnsResourceRecord
*rr
) {
591 r
= set_ensure_allocated(&d
->revoked_by_rr
, &dns_resource_record_hash_ops
);
595 r
= set_put(d
->revoked_by_rr
, rr
);
599 dns_resource_record_ref(rr
);
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
;
609 /* Remember that this is a revoked trust anchor RR */
610 r
= dns_trust_anchor_revoked_put(d
, rr
);
614 /* Remove this from the positive trust anchor */
615 old_answer
= hashmap_get(d
->positive_by_key
, rr
->key
);
619 new_answer
= dns_answer_ref(old_answer
);
621 r
= dns_answer_remove_by_rr(&new_answer
, rr
);
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
),
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
);
638 r
= hashmap_replace(d
->positive_by_key
, new_answer
->items
[0].rr
->key
, new_answer
);
643 dns_answer_unref(old_answer
);
647 static int dns_trust_anchor_check_revoked_one(DnsTrustAnchor
*d
, DnsResourceRecord
*revoked_dnskey
) {
652 assert(revoked_dnskey
);
653 assert(revoked_dnskey
->key
->type
== DNS_TYPE_DNSKEY
);
654 assert(revoked_dnskey
->dnskey
.flags
& DNSKEY_FLAG_REVOKE
);
656 a
= hashmap_get(d
->positive_by_key
, revoked_dnskey
->key
);
658 DnsResourceRecord
*anchor
;
660 /* First, look for the precise DNSKEY in our trust anchor database */
662 DNS_ANSWER_FOREACH(anchor
, a
) {
664 if (anchor
->dnskey
.protocol
!= revoked_dnskey
->dnskey
.protocol
)
667 if (anchor
->dnskey
.algorithm
!= revoked_dnskey
->dnskey
.algorithm
)
670 if (anchor
->dnskey
.key_size
!= revoked_dnskey
->dnskey
.key_size
)
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
)
679 if (memcmp(anchor
->dnskey
.key
, revoked_dnskey
->dnskey
.key
, anchor
->dnskey
.key_size
) != 0)
682 dns_trust_anchor_remove_revoked(d
, anchor
);
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
)));
689 DnsResourceRecord
*anchor
;
691 /* Second, look for DS RRs matching this DNSKEY in our trust anchor database */
693 DNS_ANSWER_FOREACH(anchor
, a
) {
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);
705 dns_trust_anchor_remove_revoked(d
, anchor
);
713 int dns_trust_anchor_check_revoked(DnsTrustAnchor
*d
, DnsResourceRecord
*dnskey
, DnsAnswer
*rrs
) {
714 DnsResourceRecord
*rrsig
;
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. */
724 if (dnskey
->key
->type
!= DNS_TYPE_DNSKEY
)
727 /* Is this DNSKEY revoked? */
728 if ((dnskey
->dnskey
.flags
& DNSKEY_FLAG_REVOKE
) == 0)
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
)))
737 /* Look for a self-signed RRSIG in the other rrs belonging to this DNSKEY */
738 DNS_ANSWER_FOREACH(rrsig
, rrs
) {
741 if (rrsig
->key
->type
!= DNS_TYPE_RRSIG
)
744 r
= dnssec_rrsig_match_dnskey(rrsig
, dnskey
, true);
750 r
= dnssec_verify_rrset(rrs
, dnskey
->key
, rrsig
, dnskey
, USEC_INFINITY
, &result
);
753 if (result
!= DNSSEC_VALIDATED
)
756 /* Bingo! This is a revoked self-signed DNSKEY. Let's
757 * see if this precise one exists in our trust anchor
759 r
= dns_trust_anchor_check_revoked_one(d
, dnskey
);
769 int dns_trust_anchor_is_revoked(DnsTrustAnchor
*d
, DnsResourceRecord
*rr
) {
772 if (!IN_SET(rr
->key
->type
, DNS_TYPE_DS
, DNS_TYPE_DNSKEY
))
775 return set_contains(d
->revoked_by_rr
, rr
);