2 This file is part of systemd.
4 Copyright 2015 Lennart Poettering
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.
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.
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/>.
20 #include "sd-messages.h"
22 #include "alloc-util.h"
23 #include "conf-files.h"
25 #include "dns-domain.h"
28 #include "hexdecoct.h"
29 #include "parse-util.h"
30 #include "resolved-dns-trust-anchor.h"
31 #include "resolved-dns-dnssec.h"
33 #include "string-util.h"
36 static const char trust_anchor_dirs
[] = CONF_PATHS_NULSTR("dnssec-trust-anchors.d");
38 /* The first DS RR from https://data.iana.org/root-anchors/root-anchors.xml, retrieved December 2015 */
39 static const uint8_t root_digest1
[] =
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 };
43 /* The second DS RR from https://data.iana.org/root-anchors/root-anchors.xml, retrieved February 2017 */
44 static const uint8_t root_digest2
[] =
45 { 0xE0, 0x6D, 0x44, 0xB8, 0x0B, 0x8F, 0x1D, 0x39, 0xA9, 0x5C, 0x0B, 0x0D, 0x7C, 0x65, 0xD0, 0x84,
46 0x58, 0xE8, 0x80, 0x40, 0x9B, 0xBC, 0x68, 0x34, 0x57, 0x10, 0x42, 0x37, 0xC7, 0xF8, 0xEC, 0x8D };
48 static bool dns_trust_anchor_knows_domain_positive(DnsTrustAnchor
*d
, const char *name
) {
51 /* Returns true if there's an entry for the specified domain
52 * name in our trust anchor */
55 hashmap_contains(d
->positive_by_key
, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN
, DNS_TYPE_DNSKEY
, name
)) ||
56 hashmap_contains(d
->positive_by_key
, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN
, DNS_TYPE_DS
, name
));
59 static int add_root_ksk(
68 _cleanup_(dns_resource_record_unrefp
) DnsResourceRecord
*rr
= NULL
;
71 rr
= dns_resource_record_new(key
);
75 rr
->ds
.key_tag
= key_tag
;
76 rr
->ds
.algorithm
= algorithm
;
77 rr
->ds
.digest_type
= digest_type
;
78 rr
->ds
.digest_size
= digest_size
;
79 rr
->ds
.digest
= memdup(digest
, rr
->ds
.digest_size
);
83 r
= dns_answer_add(answer
, rr
, 0, DNS_ANSWER_AUTHENTICATED
);
90 static int dns_trust_anchor_add_builtin_positive(DnsTrustAnchor
*d
) {
91 _cleanup_(dns_answer_unrefp
) DnsAnswer
*answer
= NULL
;
92 _cleanup_(dns_resource_key_unrefp
) DnsResourceKey
*key
= NULL
;
97 r
= hashmap_ensure_allocated(&d
->positive_by_key
, &dns_resource_key_hash_ops
);
101 /* Only add the built-in trust anchor if there's neither a DS nor a DNSKEY defined for the root domain. That
102 * way users have an easy way to override the root domain DS/DNSKEY data. */
103 if (dns_trust_anchor_knows_domain_positive(d
, "."))
106 key
= dns_resource_key_new(DNS_CLASS_IN
, DNS_TYPE_DS
, "");
110 answer
= dns_answer_new(2);
114 /* Add the two RRs from https://data.iana.org/root-anchors/root-anchors.xml */
115 r
= add_root_ksk(answer
, key
, 19036, DNSSEC_ALGORITHM_RSASHA256
, DNSSEC_DIGEST_SHA256
, root_digest1
, sizeof(root_digest1
));
119 r
= add_root_ksk(answer
, key
, 20326, DNSSEC_ALGORITHM_RSASHA256
, DNSSEC_DIGEST_SHA256
, root_digest2
, sizeof(root_digest2
));
123 r
= hashmap_put(d
->positive_by_key
, key
, answer
);
131 static int dns_trust_anchor_add_builtin_negative(DnsTrustAnchor
*d
) {
133 static const char private_domains
[] =
134 /* RFC 6761 says that .test is a special domain for
135 * testing and not to be installed in the root zone */
138 /* RFC 6761 says that these reverse IP lookup ranges
139 * are for private addresses, and hence should not
140 * show up in the root zone */
142 "16.172.in-addr.arpa\0"
143 "17.172.in-addr.arpa\0"
144 "18.172.in-addr.arpa\0"
145 "19.172.in-addr.arpa\0"
146 "20.172.in-addr.arpa\0"
147 "21.172.in-addr.arpa\0"
148 "22.172.in-addr.arpa\0"
149 "23.172.in-addr.arpa\0"
150 "24.172.in-addr.arpa\0"
151 "25.172.in-addr.arpa\0"
152 "26.172.in-addr.arpa\0"
153 "27.172.in-addr.arpa\0"
154 "28.172.in-addr.arpa\0"
155 "29.172.in-addr.arpa\0"
156 "30.172.in-addr.arpa\0"
157 "31.172.in-addr.arpa\0"
158 "168.192.in-addr.arpa\0"
160 /* The same, but for IPv6. */
163 /* RFC 6762 reserves the .local domain for Multicast
164 * DNS, it hence cannot appear in the root zone. (Note
165 * that we by default do not route .local traffic to
166 * DNS anyway, except when a configured search domain
170 /* These two are well known, popular private zone
171 * TLDs, that are blocked from delegation, according
173 * http://icannwiki.com/Name_Collision#NGPC_Resolution
175 * There's also ongoing work on making this official
177 * https://www.ietf.org/archive/id/draft-chapin-additional-reserved-tlds-02.txt */
181 /* The following four TLDs are suggested for private
182 * zones in RFC 6762, Appendix G, and are hence very
183 * unlikely to be made official TLDs any day soon */
194 /* Only add the built-in trust anchor if there's no negative
195 * trust anchor defined at all. This enables easy overriding
196 * of negative trust anchors. */
198 if (set_size(d
->negative_by_name
) > 0)
201 r
= set_ensure_allocated(&d
->negative_by_name
, &dns_name_hash_ops
);
205 /* We add a couple of domains as default negative trust
206 * anchors, where it's very unlikely they will be installed in
207 * the root zone. If they exist they must be private, and thus
210 NULSTR_FOREACH(name
, private_domains
) {
212 if (dns_trust_anchor_knows_domain_positive(d
, name
))
215 r
= set_put_strdup(d
->negative_by_name
, name
);
223 static int dns_trust_anchor_load_positive(DnsTrustAnchor
*d
, const char *path
, unsigned line
, const char *s
) {
224 _cleanup_(dns_resource_record_unrefp
) DnsResourceRecord
*rr
= NULL
;
225 _cleanup_free_
char *domain
= NULL
, *class = NULL
, *type
= NULL
;
226 _cleanup_(dns_answer_unrefp
) DnsAnswer
*answer
= NULL
;
227 DnsAnswer
*old_answer
= NULL
;
234 r
= extract_first_word(&p
, &domain
, NULL
, EXTRACT_QUOTES
);
236 return log_warning_errno(r
, "Unable to parse domain in line %s:%u: %m", path
, line
);
238 if (!dns_name_is_valid(domain
)) {
239 log_warning("Domain name %s is invalid, at line %s:%u, ignoring line.", domain
, path
, line
);
243 r
= extract_many_words(&p
, NULL
, 0, &class, &type
, NULL
);
245 return log_warning_errno(r
, "Unable to parse class and type in line %s:%u: %m", path
, line
);
247 log_warning("Missing class or type in line %s:%u", path
, line
);
251 if (!strcaseeq(class, "IN")) {
252 log_warning("RR class %s is not supported, ignoring line %s:%u.", class, path
, line
);
256 if (strcaseeq(type
, "DS")) {
257 _cleanup_free_
char *key_tag
= NULL
, *algorithm
= NULL
, *digest_type
= NULL
, *digest
= NULL
;
258 _cleanup_free_
void *dd
= NULL
;
263 r
= extract_many_words(&p
, NULL
, 0, &key_tag
, &algorithm
, &digest_type
, &digest
, NULL
);
265 log_warning_errno(r
, "Failed to parse DS parameters on line %s:%u: %m", path
, line
);
269 log_warning("Missing DS parameters on line %s:%u", path
, line
);
273 r
= safe_atou16(key_tag
, &kt
);
275 return log_warning_errno(r
, "Failed to parse DS key tag %s on line %s:%u: %m", key_tag
, path
, line
);
277 a
= dnssec_algorithm_from_string(algorithm
);
279 log_warning("Failed to parse DS algorithm %s on line %s:%u", algorithm
, path
, line
);
283 dt
= dnssec_digest_from_string(digest_type
);
285 log_warning("Failed to parse DS digest type %s on line %s:%u", digest_type
, path
, line
);
289 r
= unhexmem(digest
, strlen(digest
), &dd
, &l
);
291 log_warning("Failed to parse DS digest %s on line %s:%u", digest
, path
, line
);
295 rr
= dns_resource_record_new_full(DNS_CLASS_IN
, DNS_TYPE_DS
, domain
);
300 rr
->ds
.algorithm
= a
;
301 rr
->ds
.digest_type
= dt
;
302 rr
->ds
.digest_size
= l
;
306 } else if (strcaseeq(type
, "DNSKEY")) {
307 _cleanup_free_
char *flags
= NULL
, *protocol
= NULL
, *algorithm
= NULL
, *key
= NULL
;
308 _cleanup_free_
void *k
= NULL
;
313 r
= extract_many_words(&p
, NULL
, 0, &flags
, &protocol
, &algorithm
, &key
, NULL
);
315 return log_warning_errno(r
, "Failed to parse DNSKEY parameters on line %s:%u: %m", path
, line
);
317 log_warning("Missing DNSKEY parameters on line %s:%u", path
, line
);
321 if (!streq(protocol
, "3")) {
322 log_warning("DNSKEY Protocol is not 3 on line %s:%u", path
, line
);
326 r
= safe_atou16(flags
, &f
);
328 return log_warning_errno(r
, "Failed to parse DNSKEY flags field %s on line %s:%u", flags
, path
, line
);
329 if ((f
& DNSKEY_FLAG_ZONE_KEY
) == 0) {
330 log_warning("DNSKEY lacks zone key bit set on line %s:%u", path
, line
);
333 if ((f
& DNSKEY_FLAG_REVOKE
)) {
334 log_warning("DNSKEY is already revoked on line %s:%u", path
, line
);
338 a
= dnssec_algorithm_from_string(algorithm
);
340 log_warning("Failed to parse DNSKEY algorithm %s on line %s:%u", algorithm
, path
, line
);
344 r
= unbase64mem(key
, strlen(key
), &k
, &l
);
346 return log_warning_errno(r
, "Failed to parse DNSKEY key data %s on line %s:%u", key
, path
, line
);
348 rr
= dns_resource_record_new_full(DNS_CLASS_IN
, DNS_TYPE_DNSKEY
, domain
);
352 rr
->dnskey
.flags
= f
;
353 rr
->dnskey
.protocol
= 3;
354 rr
->dnskey
.algorithm
= a
;
355 rr
->dnskey
.key_size
= l
;
360 log_warning("RR type %s is not supported, ignoring line %s:%u.", type
, path
, line
);
365 log_warning("Trailing garbage on line %s:%u, ignoring line.", path
, line
);
369 r
= hashmap_ensure_allocated(&d
->positive_by_key
, &dns_resource_key_hash_ops
);
373 old_answer
= hashmap_get(d
->positive_by_key
, rr
->key
);
374 answer
= dns_answer_ref(old_answer
);
376 r
= dns_answer_add_extend(&answer
, rr
, 0, DNS_ANSWER_AUTHENTICATED
);
378 return log_error_errno(r
, "Failed to add trust anchor RR: %m");
380 r
= hashmap_replace(d
->positive_by_key
, rr
->key
, answer
);
382 return log_error_errno(r
, "Failed to add answer to trust anchor: %m");
384 old_answer
= dns_answer_unref(old_answer
);
390 static int dns_trust_anchor_load_negative(DnsTrustAnchor
*d
, const char *path
, unsigned line
, const char *s
) {
391 _cleanup_free_
char *domain
= NULL
;
398 r
= extract_first_word(&p
, &domain
, NULL
, EXTRACT_QUOTES
);
400 return log_warning_errno(r
, "Unable to parse line %s:%u: %m", path
, line
);
402 if (!dns_name_is_valid(domain
)) {
403 log_warning("Domain name %s is invalid, at line %s:%u, ignoring line.", domain
, path
, line
);
408 log_warning("Trailing garbage at line %s:%u, ignoring line.", path
, line
);
412 r
= set_ensure_allocated(&d
->negative_by_name
, &dns_name_hash_ops
);
416 r
= set_put(d
->negative_by_name
, domain
);
425 static int dns_trust_anchor_load_files(
428 int (*loader
)(DnsTrustAnchor
*d
, const char *path
, unsigned n
, const char *line
)) {
430 _cleanup_strv_free_
char **files
= NULL
;
438 r
= conf_files_list_nulstr(&files
, suffix
, NULL
, 0, trust_anchor_dirs
);
440 return log_error_errno(r
, "Failed to enumerate %s trust anchor files: %m", suffix
);
442 STRV_FOREACH(f
, files
) {
443 _cleanup_fclose_
FILE *g
= NULL
;
452 log_warning_errno(errno
, "Failed to open %s: %m", *f
);
456 FOREACH_LINE(line
, g
, log_warning_errno(errno
, "Failed to read %s, ignoring: %m", *f
)) {
468 (void) loader(d
, *f
, n
, l
);
475 static int domain_name_cmp(const void *a
, const void *b
) {
476 char **x
= (char**) a
, **y
= (char**) b
;
478 return dns_name_compare_func(*x
, *y
);
481 static int dns_trust_anchor_dump(DnsTrustAnchor
*d
) {
487 if (hashmap_isempty(d
->positive_by_key
))
488 log_info("No positive trust anchors defined.");
490 log_info("Positive Trust Anchors:");
491 HASHMAP_FOREACH(a
, d
->positive_by_key
, i
) {
492 DnsResourceRecord
*rr
;
494 DNS_ANSWER_FOREACH(rr
, a
)
495 log_info("%s", dns_resource_record_to_string(rr
));
499 if (set_isempty(d
->negative_by_name
))
500 log_info("No negative trust anchors defined.");
502 _cleanup_free_
char **l
= NULL
, *j
= NULL
;
504 l
= set_get_strv(d
->negative_by_name
);
508 qsort_safe(l
, set_size(d
->negative_by_name
), sizeof(char*), domain_name_cmp
);
510 j
= strv_join(l
, " ");
514 log_info("Negative trust anchors: %s", j
);
520 int dns_trust_anchor_load(DnsTrustAnchor
*d
) {
525 /* If loading things from disk fails, we don't consider this fatal */
526 (void) dns_trust_anchor_load_files(d
, ".positive", dns_trust_anchor_load_positive
);
527 (void) dns_trust_anchor_load_files(d
, ".negative", dns_trust_anchor_load_negative
);
529 /* However, if the built-in DS fails, then we have a problem. */
530 r
= dns_trust_anchor_add_builtin_positive(d
);
532 return log_error_errno(r
, "Failed to add built-in positive trust anchor: %m");
534 r
= dns_trust_anchor_add_builtin_negative(d
);
536 return log_error_errno(r
, "Failed to add built-in negative trust anchor: %m");
538 dns_trust_anchor_dump(d
);
543 void dns_trust_anchor_flush(DnsTrustAnchor
*d
) {
545 DnsResourceRecord
*rr
;
549 while ((a
= hashmap_steal_first(d
->positive_by_key
)))
551 d
->positive_by_key
= hashmap_free(d
->positive_by_key
);
553 while ((rr
= set_steal_first(d
->revoked_by_rr
)))
554 dns_resource_record_unref(rr
);
555 d
->revoked_by_rr
= set_free(d
->revoked_by_rr
);
557 d
->negative_by_name
= set_free_free(d
->negative_by_name
);
560 int dns_trust_anchor_lookup_positive(DnsTrustAnchor
*d
, const DnsResourceKey
*key
, DnsAnswer
**ret
) {
567 /* We only serve DS and DNSKEY RRs. */
568 if (!IN_SET(key
->type
, DNS_TYPE_DS
, DNS_TYPE_DNSKEY
))
571 a
= hashmap_get(d
->positive_by_key
, key
);
575 *ret
= dns_answer_ref(a
);
579 int dns_trust_anchor_lookup_negative(DnsTrustAnchor
*d
, const char *name
) {
586 /* If the domain is listed as-is in the NTA database, then that counts */
587 if (set_contains(d
->negative_by_name
, name
))
590 /* If the domain isn't listed as NTA, but is listed as positive trust anchor, then that counts. See RFC
591 * 7646, section 1.1 */
592 if (hashmap_contains(d
->positive_by_key
, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN
, DNS_TYPE_DS
, name
)))
595 if (hashmap_contains(d
->positive_by_key
, &DNS_RESOURCE_KEY_CONST(DNS_CLASS_IN
, DNS_TYPE_KEY
, name
)))
598 /* And now, let's look at the parent, and check that too */
599 r
= dns_name_parent(&name
);
609 static int dns_trust_anchor_revoked_put(DnsTrustAnchor
*d
, DnsResourceRecord
*rr
) {
614 r
= set_ensure_allocated(&d
->revoked_by_rr
, &dns_resource_record_hash_ops
);
618 r
= set_put(d
->revoked_by_rr
, rr
);
622 dns_resource_record_ref(rr
);
627 static int dns_trust_anchor_remove_revoked(DnsTrustAnchor
*d
, DnsResourceRecord
*rr
) {
628 _cleanup_(dns_answer_unrefp
) DnsAnswer
*new_answer
= NULL
;
629 DnsAnswer
*old_answer
;
632 /* Remember that this is a revoked trust anchor RR */
633 r
= dns_trust_anchor_revoked_put(d
, rr
);
637 /* Remove this from the positive trust anchor */
638 old_answer
= hashmap_get(d
->positive_by_key
, rr
->key
);
642 new_answer
= dns_answer_ref(old_answer
);
644 r
= dns_answer_remove_by_rr(&new_answer
, rr
);
648 /* We found the key! Warn the user */
649 log_struct(LOG_WARNING
,
650 "MESSAGE_ID=" SD_MESSAGE_DNSSEC_TRUST_ANCHOR_REVOKED_STR
,
651 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
)),
652 "TRUST_ANCHOR=%s", dns_resource_record_to_string(rr
),
655 if (dns_answer_size(new_answer
) <= 0) {
656 assert_se(hashmap_remove(d
->positive_by_key
, rr
->key
) == old_answer
);
657 dns_answer_unref(old_answer
);
661 r
= hashmap_replace(d
->positive_by_key
, new_answer
->items
[0].rr
->key
, new_answer
);
666 dns_answer_unref(old_answer
);
670 static int dns_trust_anchor_check_revoked_one(DnsTrustAnchor
*d
, DnsResourceRecord
*revoked_dnskey
) {
675 assert(revoked_dnskey
);
676 assert(revoked_dnskey
->key
->type
== DNS_TYPE_DNSKEY
);
677 assert(revoked_dnskey
->dnskey
.flags
& DNSKEY_FLAG_REVOKE
);
679 a
= hashmap_get(d
->positive_by_key
, revoked_dnskey
->key
);
681 DnsResourceRecord
*anchor
;
683 /* First, look for the precise DNSKEY in our trust anchor database */
685 DNS_ANSWER_FOREACH(anchor
, a
) {
687 if (anchor
->dnskey
.protocol
!= revoked_dnskey
->dnskey
.protocol
)
690 if (anchor
->dnskey
.algorithm
!= revoked_dnskey
->dnskey
.algorithm
)
693 if (anchor
->dnskey
.key_size
!= revoked_dnskey
->dnskey
.key_size
)
696 /* Note that we allow the REVOKE bit to be
697 * different! It will be set in the revoked
698 * key, but unset in our version of it */
699 if (((anchor
->dnskey
.flags
^ revoked_dnskey
->dnskey
.flags
) | DNSKEY_FLAG_REVOKE
) != DNSKEY_FLAG_REVOKE
)
702 if (memcmp(anchor
->dnskey
.key
, revoked_dnskey
->dnskey
.key
, anchor
->dnskey
.key_size
) != 0)
705 dns_trust_anchor_remove_revoked(d
, anchor
);
710 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
)));
712 DnsResourceRecord
*anchor
;
714 /* Second, look for DS RRs matching this DNSKEY in our trust anchor database */
716 DNS_ANSWER_FOREACH(anchor
, a
) {
718 /* We set mask_revoke to true here, since our
719 * DS fingerprint will be the one of the
720 * unrevoked DNSKEY, but the one we got passed
721 * here has the bit set. */
722 r
= dnssec_verify_dnskey_by_ds(revoked_dnskey
, anchor
, true);
728 dns_trust_anchor_remove_revoked(d
, anchor
);
736 int dns_trust_anchor_check_revoked(DnsTrustAnchor
*d
, DnsResourceRecord
*dnskey
, DnsAnswer
*rrs
) {
737 DnsResourceRecord
*rrsig
;
743 /* Looks if "dnskey" is a self-signed RR that has been revoked
744 * and matches one of our trust anchor entries. If so, removes
745 * it from the trust anchor and returns > 0. */
747 if (dnskey
->key
->type
!= DNS_TYPE_DNSKEY
)
750 /* Is this DNSKEY revoked? */
751 if ((dnskey
->dnskey
.flags
& DNSKEY_FLAG_REVOKE
) == 0)
754 /* Could this be interesting to us at all? If not,
755 * there's no point in looking for and verifying a
756 * self-signed RRSIG. */
757 if (!dns_trust_anchor_knows_domain_positive(d
, dns_resource_key_name(dnskey
->key
)))
760 /* Look for a self-signed RRSIG in the other rrs belonging to this DNSKEY */
761 DNS_ANSWER_FOREACH(rrsig
, rrs
) {
764 if (rrsig
->key
->type
!= DNS_TYPE_RRSIG
)
767 r
= dnssec_rrsig_match_dnskey(rrsig
, dnskey
, true);
773 r
= dnssec_verify_rrset(rrs
, dnskey
->key
, rrsig
, dnskey
, USEC_INFINITY
, &result
);
776 if (result
!= DNSSEC_VALIDATED
)
779 /* Bingo! This is a revoked self-signed DNSKEY. Let's
780 * see if this precise one exists in our trust anchor
782 r
= dns_trust_anchor_check_revoked_one(d
, dnskey
);
792 int dns_trust_anchor_is_revoked(DnsTrustAnchor
*d
, DnsResourceRecord
*rr
) {
795 if (!IN_SET(rr
->key
->type
, DNS_TYPE_DS
, DNS_TYPE_DNSKEY
))
798 return set_contains(d
->revoked_by_rr
, rr
);