1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
3 #include "alloc-util.h"
4 #include "dns-domain.h"
7 #include "gcrypt-util.h"
9 #include "memory-util.h"
10 #include "resolved-dns-dnssec.h"
11 #include "resolved-dns-packet.h"
12 #include "sort-util.h"
13 #include "string-table.h"
15 #define VERIFY_RRS_MAX 256
16 #define MAX_KEY_SIZE (32*1024)
18 /* Permit a maximum clock skew of 1h 10min. This should be enough to deal with DST confusion */
19 #define SKEW_MAX (1*USEC_PER_HOUR + 10*USEC_PER_MINUTE)
21 /* Maximum number of NSEC3 iterations we'll do. RFC5155 says 2500 shall be the maximum useful value */
22 #define NSEC3_ITERATIONS_MAX 2500
25 * The DNSSEC Chain of trust:
27 * Normal RRs are protected via RRSIG RRs in combination with DNSKEY RRs, all in the same zone
28 * DNSKEY RRs are either protected like normal RRs, or via a DS from a zone "higher" up the tree
29 * DS RRs are protected like normal RRs
32 * Normal RR → RRSIG/DNSKEY+ → DS → RRSIG/DNSKEY+ → DS → ... → DS → RRSIG/DNSKEY+ → DS
35 uint16_t dnssec_keytag(DnsResourceRecord
*dnskey
, bool mask_revoke
) {
40 /* The algorithm from RFC 4034, Appendix B. */
43 assert(dnskey
->key
->type
== DNS_TYPE_DNSKEY
);
45 f
= (uint32_t) dnskey
->dnskey
.flags
;
48 f
&= ~DNSKEY_FLAG_REVOKE
;
50 sum
= f
+ ((((uint32_t) dnskey
->dnskey
.protocol
) << 8) + (uint32_t) dnskey
->dnskey
.algorithm
);
52 p
= dnskey
->dnskey
.key
;
54 for (i
= 0; i
< dnskey
->dnskey
.key_size
; i
++)
55 sum
+= (i
& 1) == 0 ? (uint32_t) p
[i
] << 8 : (uint32_t) p
[i
];
57 sum
+= (sum
>> 16) & UINT32_C(0xFFFF);
59 return sum
& UINT32_C(0xFFFF);
64 static int rr_compare(DnsResourceRecord
* const *a
, DnsResourceRecord
* const *b
) {
65 const DnsResourceRecord
*x
= *a
, *y
= *b
;
69 /* Let's order the RRs according to RFC 4034, Section 6.3 */
72 assert(x
->wire_format
);
74 assert(y
->wire_format
);
76 m
= MIN(DNS_RESOURCE_RECORD_RDATA_SIZE(x
), DNS_RESOURCE_RECORD_RDATA_SIZE(y
));
78 r
= memcmp(DNS_RESOURCE_RECORD_RDATA(x
), DNS_RESOURCE_RECORD_RDATA(y
), m
);
82 return CMP(DNS_RESOURCE_RECORD_RDATA_SIZE(x
), DNS_RESOURCE_RECORD_RDATA_SIZE(y
));
85 static int dnssec_rsa_verify_raw(
86 const char *hash_algorithm
,
87 const void *signature
, size_t signature_size
,
88 const void *data
, size_t data_size
,
89 const void *exponent
, size_t exponent_size
,
90 const void *modulus
, size_t modulus_size
) {
92 gcry_sexp_t public_key_sexp
= NULL
, data_sexp
= NULL
, signature_sexp
= NULL
;
93 gcry_mpi_t n
= NULL
, e
= NULL
, s
= NULL
;
97 assert(hash_algorithm
);
99 ge
= gcry_mpi_scan(&s
, GCRYMPI_FMT_USG
, signature
, signature_size
, NULL
);
105 ge
= gcry_mpi_scan(&e
, GCRYMPI_FMT_USG
, exponent
, exponent_size
, NULL
);
111 ge
= gcry_mpi_scan(&n
, GCRYMPI_FMT_USG
, modulus
, modulus_size
, NULL
);
117 ge
= gcry_sexp_build(&signature_sexp
,
119 "(sig-val (rsa (s %m)))",
127 ge
= gcry_sexp_build(&data_sexp
,
129 "(data (flags pkcs1) (hash %s %b))",
138 ge
= gcry_sexp_build(&public_key_sexp
,
140 "(public-key (rsa (n %m) (e %m)))",
148 ge
= gcry_pk_verify(signature_sexp
, data_sexp
, public_key_sexp
);
149 if (gpg_err_code(ge
) == GPG_ERR_BAD_SIGNATURE
)
152 log_debug("RSA signature check failed: %s", gpg_strerror(ge
));
166 gcry_sexp_release(public_key_sexp
);
168 gcry_sexp_release(signature_sexp
);
170 gcry_sexp_release(data_sexp
);
175 static int dnssec_rsa_verify(
176 const char *hash_algorithm
,
177 const void *hash
, size_t hash_size
,
178 DnsResourceRecord
*rrsig
,
179 DnsResourceRecord
*dnskey
) {
181 size_t exponent_size
, modulus_size
;
182 void *exponent
, *modulus
;
184 assert(hash_algorithm
);
186 assert(hash_size
> 0);
190 if (*(uint8_t*) dnskey
->dnskey
.key
== 0) {
191 /* exponent is > 255 bytes long */
193 exponent
= (uint8_t*) dnskey
->dnskey
.key
+ 3;
195 ((size_t) (((uint8_t*) dnskey
->dnskey
.key
)[1]) << 8) |
196 ((size_t) ((uint8_t*) dnskey
->dnskey
.key
)[2]);
198 if (exponent_size
< 256)
201 if (3 + exponent_size
>= dnskey
->dnskey
.key_size
)
204 modulus
= (uint8_t*) dnskey
->dnskey
.key
+ 3 + exponent_size
;
205 modulus_size
= dnskey
->dnskey
.key_size
- 3 - exponent_size
;
208 /* exponent is <= 255 bytes long */
210 exponent
= (uint8_t*) dnskey
->dnskey
.key
+ 1;
211 exponent_size
= (size_t) ((uint8_t*) dnskey
->dnskey
.key
)[0];
213 if (exponent_size
<= 0)
216 if (1 + exponent_size
>= dnskey
->dnskey
.key_size
)
219 modulus
= (uint8_t*) dnskey
->dnskey
.key
+ 1 + exponent_size
;
220 modulus_size
= dnskey
->dnskey
.key_size
- 1 - exponent_size
;
223 return dnssec_rsa_verify_raw(
225 rrsig
->rrsig
.signature
, rrsig
->rrsig
.signature_size
,
227 exponent
, exponent_size
,
228 modulus
, modulus_size
);
231 static int dnssec_ecdsa_verify_raw(
232 const char *hash_algorithm
,
234 const void *signature_r
, size_t signature_r_size
,
235 const void *signature_s
, size_t signature_s_size
,
236 const void *data
, size_t data_size
,
237 const void *key
, size_t key_size
) {
239 gcry_sexp_t public_key_sexp
= NULL
, data_sexp
= NULL
, signature_sexp
= NULL
;
240 gcry_mpi_t q
= NULL
, r
= NULL
, s
= NULL
;
244 assert(hash_algorithm
);
246 ge
= gcry_mpi_scan(&r
, GCRYMPI_FMT_USG
, signature_r
, signature_r_size
, NULL
);
252 ge
= gcry_mpi_scan(&s
, GCRYMPI_FMT_USG
, signature_s
, signature_s_size
, NULL
);
258 ge
= gcry_mpi_scan(&q
, GCRYMPI_FMT_USG
, key
, key_size
, NULL
);
264 ge
= gcry_sexp_build(&signature_sexp
,
266 "(sig-val (ecdsa (r %m) (s %m)))",
274 ge
= gcry_sexp_build(&data_sexp
,
276 "(data (flags rfc6979) (hash %s %b))",
285 ge
= gcry_sexp_build(&public_key_sexp
,
287 "(public-key (ecc (curve %s) (q %m)))",
295 ge
= gcry_pk_verify(signature_sexp
, data_sexp
, public_key_sexp
);
296 if (gpg_err_code(ge
) == GPG_ERR_BAD_SIGNATURE
)
299 log_debug("ECDSA signature check failed: %s", gpg_strerror(ge
));
312 gcry_sexp_release(public_key_sexp
);
314 gcry_sexp_release(signature_sexp
);
316 gcry_sexp_release(data_sexp
);
321 static int dnssec_ecdsa_verify(
322 const char *hash_algorithm
,
324 const void *hash
, size_t hash_size
,
325 DnsResourceRecord
*rrsig
,
326 DnsResourceRecord
*dnskey
) {
337 if (algorithm
== DNSSEC_ALGORITHM_ECDSAP256SHA256
) {
339 curve
= "NIST P-256";
340 } else if (algorithm
== DNSSEC_ALGORITHM_ECDSAP384SHA384
) {
342 curve
= "NIST P-384";
346 if (dnskey
->dnskey
.key_size
!= key_size
* 2)
349 if (rrsig
->rrsig
.signature_size
!= key_size
* 2)
352 q
= newa(uint8_t, key_size
*2 + 1);
353 q
[0] = 0x04; /* Prepend 0x04 to indicate an uncompressed key */
354 memcpy(q
+1, dnskey
->dnskey
.key
, key_size
*2);
356 return dnssec_ecdsa_verify_raw(
359 rrsig
->rrsig
.signature
, key_size
,
360 (uint8_t*) rrsig
->rrsig
.signature
+ key_size
, key_size
,
365 #if GCRYPT_VERSION_NUMBER >= 0x010600
366 static int dnssec_eddsa_verify_raw(
368 const void *signature_r
, size_t signature_r_size
,
369 const void *signature_s
, size_t signature_s_size
,
370 const void *data
, size_t data_size
,
371 const void *key
, size_t key_size
) {
373 gcry_sexp_t public_key_sexp
= NULL
, data_sexp
= NULL
, signature_sexp
= NULL
;
377 ge
= gcry_sexp_build(&signature_sexp
,
379 "(sig-val (eddsa (r %b) (s %b)))",
380 (int) signature_r_size
,
382 (int) signature_s_size
,
389 ge
= gcry_sexp_build(&data_sexp
,
391 "(data (flags eddsa) (hash-algo sha512) (value %b))",
399 ge
= gcry_sexp_build(&public_key_sexp
,
401 "(public-key (ecc (curve %s) (flags eddsa) (q %b)))",
410 ge
= gcry_pk_verify(signature_sexp
, data_sexp
, public_key_sexp
);
411 if (gpg_err_code(ge
) == GPG_ERR_BAD_SIGNATURE
)
414 log_debug("EdDSA signature check failed: %s", gpg_strerror(ge
));
420 gcry_sexp_release(public_key_sexp
);
422 gcry_sexp_release(signature_sexp
);
424 gcry_sexp_release(data_sexp
);
429 static int dnssec_eddsa_verify(
431 const void *data
, size_t data_size
,
432 DnsResourceRecord
*rrsig
,
433 DnsResourceRecord
*dnskey
) {
437 if (algorithm
== DNSSEC_ALGORITHM_ED25519
) {
443 if (dnskey
->dnskey
.key_size
!= key_size
)
446 if (rrsig
->rrsig
.signature_size
!= key_size
* 2)
449 return dnssec_eddsa_verify_raw(
451 rrsig
->rrsig
.signature
, key_size
,
452 (uint8_t*) rrsig
->rrsig
.signature
+ key_size
, key_size
,
454 dnskey
->dnskey
.key
, key_size
);
458 static void md_add_uint8(gcry_md_hd_t md
, uint8_t v
) {
459 gcry_md_write(md
, &v
, sizeof(v
));
462 static void md_add_uint16(gcry_md_hd_t md
, uint16_t v
) {
464 gcry_md_write(md
, &v
, sizeof(v
));
467 static void fwrite_uint8(FILE *fp
, uint8_t v
) {
468 fwrite(&v
, sizeof(v
), 1, fp
);
471 static void fwrite_uint16(FILE *fp
, uint16_t v
) {
473 fwrite(&v
, sizeof(v
), 1, fp
);
476 static void fwrite_uint32(FILE *fp
, uint32_t v
) {
478 fwrite(&v
, sizeof(v
), 1, fp
);
481 static int dnssec_rrsig_prepare(DnsResourceRecord
*rrsig
) {
482 int n_key_labels
, n_signer_labels
;
486 /* Checks whether the specified RRSIG RR is somewhat valid, and initializes the .n_skip_labels_source and
487 * .n_skip_labels_signer fields so that we can use them later on. */
490 assert(rrsig
->key
->type
== DNS_TYPE_RRSIG
);
492 /* Check if this RRSIG RR is already prepared */
493 if (rrsig
->n_skip_labels_source
!= UINT_MAX
)
496 if (rrsig
->rrsig
.inception
> rrsig
->rrsig
.expiration
)
499 name
= dns_resource_key_name(rrsig
->key
);
501 n_key_labels
= dns_name_count_labels(name
);
502 if (n_key_labels
< 0)
504 if (rrsig
->rrsig
.labels
> n_key_labels
)
507 n_signer_labels
= dns_name_count_labels(rrsig
->rrsig
.signer
);
508 if (n_signer_labels
< 0)
509 return n_signer_labels
;
510 if (n_signer_labels
> rrsig
->rrsig
.labels
)
513 r
= dns_name_skip(name
, n_key_labels
- n_signer_labels
, &name
);
519 /* Check if the signer is really a suffix of us */
520 r
= dns_name_equal(name
, rrsig
->rrsig
.signer
);
526 rrsig
->n_skip_labels_source
= n_key_labels
- rrsig
->rrsig
.labels
;
527 rrsig
->n_skip_labels_signer
= n_key_labels
- n_signer_labels
;
532 static int dnssec_rrsig_expired(DnsResourceRecord
*rrsig
, usec_t realtime
) {
533 usec_t expiration
, inception
, skew
;
536 assert(rrsig
->key
->type
== DNS_TYPE_RRSIG
);
538 if (realtime
== USEC_INFINITY
)
539 realtime
= now(CLOCK_REALTIME
);
541 expiration
= rrsig
->rrsig
.expiration
* USEC_PER_SEC
;
542 inception
= rrsig
->rrsig
.inception
* USEC_PER_SEC
;
544 /* Consider inverted validity intervals as expired */
545 if (inception
> expiration
)
548 /* Permit a certain amount of clock skew of 10% of the valid
549 * time range. This takes inspiration from unbound's
551 skew
= (expiration
- inception
) / 10;
555 if (inception
< skew
)
560 if (expiration
+ skew
< expiration
)
561 expiration
= USEC_INFINITY
;
565 return realtime
< inception
|| realtime
> expiration
;
568 static int algorithm_to_gcrypt_md(uint8_t algorithm
) {
570 /* Translates a DNSSEC signature algorithm into a gcrypt
573 * Note that we implement all algorithms listed as "Must
574 * implement" and "Recommended to Implement" in RFC6944. We
575 * don't implement any algorithms that are listed as
576 * "Optional" or "Must Not Implement". Specifically, we do not
577 * implement RSAMD5, DSASHA1, DH, DSA-NSEC3-SHA1, and
582 case DNSSEC_ALGORITHM_RSASHA1
:
583 case DNSSEC_ALGORITHM_RSASHA1_NSEC3_SHA1
:
586 case DNSSEC_ALGORITHM_RSASHA256
:
587 case DNSSEC_ALGORITHM_ECDSAP256SHA256
:
588 return GCRY_MD_SHA256
;
590 case DNSSEC_ALGORITHM_ECDSAP384SHA384
:
591 return GCRY_MD_SHA384
;
593 case DNSSEC_ALGORITHM_RSASHA512
:
594 return GCRY_MD_SHA512
;
601 static void dnssec_fix_rrset_ttl(
602 DnsResourceRecord
*list
[],
604 DnsResourceRecord
*rrsig
,
613 for (k
= 0; k
< n
; k
++) {
614 DnsResourceRecord
*rr
= list
[k
];
616 /* Pick the TTL as the minimum of the RR's TTL, the
617 * RR's original TTL according to the RRSIG and the
618 * RRSIG's own TTL, see RFC 4035, Section 5.3.3 */
619 rr
->ttl
= MIN3(rr
->ttl
, rrsig
->rrsig
.original_ttl
, rrsig
->ttl
);
620 rr
->expiry
= rrsig
->rrsig
.expiration
* USEC_PER_SEC
;
622 /* Copy over information about the signer and wildcard source of synthesis */
623 rr
->n_skip_labels_source
= rrsig
->n_skip_labels_source
;
624 rr
->n_skip_labels_signer
= rrsig
->n_skip_labels_signer
;
627 rrsig
->expiry
= rrsig
->rrsig
.expiration
* USEC_PER_SEC
;
630 int dnssec_verify_rrset(
632 const DnsResourceKey
*key
,
633 DnsResourceRecord
*rrsig
,
634 DnsResourceRecord
*dnskey
,
636 DnssecResult
*result
) {
638 uint8_t wire_format_name
[DNS_WIRE_FORMAT_HOSTNAME_MAX
];
639 DnsResourceRecord
**list
, *rr
;
640 const char *source
, *name
;
641 _cleanup_(gcry_md_closep
) gcry_md_hd_t md
= NULL
;
645 _cleanup_free_
char *sig_data
= NULL
;
646 _cleanup_fclose_
FILE *f
= NULL
;
655 assert(rrsig
->key
->type
== DNS_TYPE_RRSIG
);
656 assert(dnskey
->key
->type
== DNS_TYPE_DNSKEY
);
658 /* Verifies that the RRSet matches the specified "key" in "a",
659 * using the signature "rrsig" and the key "dnskey". It's
660 * assumed that RRSIG and DNSKEY match. */
662 r
= dnssec_rrsig_prepare(rrsig
);
664 *result
= DNSSEC_INVALID
;
670 r
= dnssec_rrsig_expired(rrsig
, realtime
);
674 *result
= DNSSEC_SIGNATURE_EXPIRED
;
678 name
= dns_resource_key_name(key
);
680 /* Some keys may only appear signed in the zone apex, and are invalid anywhere else. (SOA, NS...) */
681 if (dns_type_apex_only(rrsig
->rrsig
.type_covered
)) {
682 r
= dns_name_equal(rrsig
->rrsig
.signer
, name
);
686 *result
= DNSSEC_INVALID
;
691 /* OTOH DS RRs may not appear in the zone apex, but are valid everywhere else. */
692 if (rrsig
->rrsig
.type_covered
== DNS_TYPE_DS
) {
693 r
= dns_name_equal(rrsig
->rrsig
.signer
, name
);
697 *result
= DNSSEC_INVALID
;
702 /* Determine the "Source of Synthesis" and whether this is a wildcard RRSIG */
703 r
= dns_name_suffix(name
, rrsig
->rrsig
.labels
, &source
);
706 if (r
> 0 && !dns_type_may_wildcard(rrsig
->rrsig
.type_covered
)) {
707 /* We refuse to validate NSEC3 or SOA RRs that are synthesized from wildcards */
708 *result
= DNSSEC_INVALID
;
712 /* If we stripped a single label, then let's see if that maybe was "*". If so, we are not really
713 * synthesized from a wildcard, we are the wildcard itself. Treat that like a normal name. */
714 r
= dns_name_startswith(name
, "*");
724 /* Collect all relevant RRs in a single array, so that we can look at the RRset */
725 list
= newa(DnsResourceRecord
*, dns_answer_size(a
));
727 DNS_ANSWER_FOREACH(rr
, a
) {
728 r
= dns_resource_key_equal(key
, rr
->key
);
734 /* We need the wire format for ordering, and digest calculation */
735 r
= dns_resource_record_to_wire_format(rr
, true);
741 if (n
> VERIFY_RRS_MAX
)
748 /* Bring the RRs into canonical order */
749 typesafe_qsort(list
, n
, rr_compare
);
751 f
= open_memstream_unlocked(&sig_data
, &sig_size
);
755 fwrite_uint16(f
, rrsig
->rrsig
.type_covered
);
756 fwrite_uint8(f
, rrsig
->rrsig
.algorithm
);
757 fwrite_uint8(f
, rrsig
->rrsig
.labels
);
758 fwrite_uint32(f
, rrsig
->rrsig
.original_ttl
);
759 fwrite_uint32(f
, rrsig
->rrsig
.expiration
);
760 fwrite_uint32(f
, rrsig
->rrsig
.inception
);
761 fwrite_uint16(f
, rrsig
->rrsig
.key_tag
);
763 r
= dns_name_to_wire_format(rrsig
->rrsig
.signer
, wire_format_name
, sizeof(wire_format_name
), true);
766 fwrite(wire_format_name
, 1, r
, f
);
768 /* Convert the source of synthesis into wire format */
769 r
= dns_name_to_wire_format(source
, wire_format_name
, sizeof(wire_format_name
), true);
773 for (k
= 0; k
< n
; k
++) {
778 /* Hash the source of synthesis. If this is a wildcard, then prefix it with the *. label */
780 fwrite((uint8_t[]) { 1, '*'}, sizeof(uint8_t), 2, f
);
781 fwrite(wire_format_name
, 1, r
, f
);
783 fwrite_uint16(f
, rr
->key
->type
);
784 fwrite_uint16(f
, rr
->key
->class);
785 fwrite_uint32(f
, rrsig
->rrsig
.original_ttl
);
787 l
= DNS_RESOURCE_RECORD_RDATA_SIZE(rr
);
790 fwrite_uint16(f
, (uint16_t) l
);
791 fwrite(DNS_RESOURCE_RECORD_RDATA(rr
), 1, l
, f
);
794 r
= fflush_and_check(f
);
798 initialize_libgcrypt(false);
800 switch (rrsig
->rrsig
.algorithm
) {
801 #if GCRYPT_VERSION_NUMBER >= 0x010600
802 case DNSSEC_ALGORITHM_ED25519
:
805 case DNSSEC_ALGORITHM_ED25519
:
807 case DNSSEC_ALGORITHM_ED448
:
808 *result
= DNSSEC_UNSUPPORTED_ALGORITHM
;
811 /* OK, the RRs are now in canonical order. Let's calculate the digest */
812 md_algorithm
= algorithm_to_gcrypt_md(rrsig
->rrsig
.algorithm
);
813 if (md_algorithm
== -EOPNOTSUPP
) {
814 *result
= DNSSEC_UNSUPPORTED_ALGORITHM
;
817 if (md_algorithm
< 0)
820 gcry_md_open(&md
, md_algorithm
, 0);
824 hash_size
= gcry_md_get_algo_dlen(md_algorithm
);
825 assert(hash_size
> 0);
827 gcry_md_write(md
, sig_data
, sig_size
);
829 hash
= gcry_md_read(md
, 0);
834 switch (rrsig
->rrsig
.algorithm
) {
836 case DNSSEC_ALGORITHM_RSASHA1
:
837 case DNSSEC_ALGORITHM_RSASHA1_NSEC3_SHA1
:
838 case DNSSEC_ALGORITHM_RSASHA256
:
839 case DNSSEC_ALGORITHM_RSASHA512
:
840 r
= dnssec_rsa_verify(
841 gcry_md_algo_name(md_algorithm
),
847 case DNSSEC_ALGORITHM_ECDSAP256SHA256
:
848 case DNSSEC_ALGORITHM_ECDSAP384SHA384
:
849 r
= dnssec_ecdsa_verify(
850 gcry_md_algo_name(md_algorithm
),
851 rrsig
->rrsig
.algorithm
,
856 #if GCRYPT_VERSION_NUMBER >= 0x010600
857 case DNSSEC_ALGORITHM_ED25519
:
858 r
= dnssec_eddsa_verify(
859 rrsig
->rrsig
.algorithm
,
869 /* Now, fix the ttl, expiry, and remember the synthesizing source and the signer */
871 dnssec_fix_rrset_ttl(list
, n
, rrsig
, realtime
);
874 *result
= DNSSEC_INVALID
;
876 *result
= DNSSEC_VALIDATED_WILDCARD
;
878 *result
= DNSSEC_VALIDATED
;
883 int dnssec_rrsig_match_dnskey(DnsResourceRecord
*rrsig
, DnsResourceRecord
*dnskey
, bool revoked_ok
) {
888 /* Checks if the specified DNSKEY RR matches the key used for
889 * the signature in the specified RRSIG RR */
891 if (rrsig
->key
->type
!= DNS_TYPE_RRSIG
)
894 if (dnskey
->key
->type
!= DNS_TYPE_DNSKEY
)
896 if (dnskey
->key
->class != rrsig
->key
->class)
898 if ((dnskey
->dnskey
.flags
& DNSKEY_FLAG_ZONE_KEY
) == 0)
900 if (!revoked_ok
&& (dnskey
->dnskey
.flags
& DNSKEY_FLAG_REVOKE
))
902 if (dnskey
->dnskey
.protocol
!= 3)
904 if (dnskey
->dnskey
.algorithm
!= rrsig
->rrsig
.algorithm
)
907 if (dnssec_keytag(dnskey
, false) != rrsig
->rrsig
.key_tag
)
910 return dns_name_equal(dns_resource_key_name(dnskey
->key
), rrsig
->rrsig
.signer
);
913 int dnssec_key_match_rrsig(const DnsResourceKey
*key
, DnsResourceRecord
*rrsig
) {
917 /* Checks if the specified RRSIG RR protects the RRSet of the specified RR key. */
919 if (rrsig
->key
->type
!= DNS_TYPE_RRSIG
)
921 if (rrsig
->key
->class != key
->class)
923 if (rrsig
->rrsig
.type_covered
!= key
->type
)
926 return dns_name_equal(dns_resource_key_name(rrsig
->key
), dns_resource_key_name(key
));
929 int dnssec_verify_rrset_search(
931 const DnsResourceKey
*key
,
932 DnsAnswer
*validated_dnskeys
,
934 DnssecResult
*result
,
935 DnsResourceRecord
**ret_rrsig
) {
937 bool found_rrsig
= false, found_invalid
= false, found_expired_rrsig
= false, found_unsupported_algorithm
= false;
938 DnsResourceRecord
*rrsig
;
944 /* Verifies all RRs from "a" that match the key "key" against DNSKEYs in "validated_dnskeys" */
946 if (!a
|| a
->n_rrs
<= 0)
949 /* Iterate through each RRSIG RR. */
950 DNS_ANSWER_FOREACH(rrsig
, a
) {
951 DnsResourceRecord
*dnskey
;
952 DnsAnswerFlags flags
;
954 /* Is this an RRSIG RR that applies to RRs matching our key? */
955 r
= dnssec_key_match_rrsig(key
, rrsig
);
963 /* Look for a matching key */
964 DNS_ANSWER_FOREACH_FLAGS(dnskey
, flags
, validated_dnskeys
) {
965 DnssecResult one_result
;
967 if ((flags
& DNS_ANSWER_AUTHENTICATED
) == 0)
970 /* Is this a DNSKEY RR that matches they key of our RRSIG? */
971 r
= dnssec_rrsig_match_dnskey(rrsig
, dnskey
, false);
977 /* Take the time here, if it isn't set yet, so
978 * that we do all validations with the same
980 if (realtime
== USEC_INFINITY
)
981 realtime
= now(CLOCK_REALTIME
);
983 /* Yay, we found a matching RRSIG with a matching
984 * DNSKEY, awesome. Now let's verify all entries of
985 * the RRSet against the RRSIG and DNSKEY
988 r
= dnssec_verify_rrset(a
, key
, rrsig
, dnskey
, realtime
, &one_result
);
992 switch (one_result
) {
994 case DNSSEC_VALIDATED
:
995 case DNSSEC_VALIDATED_WILDCARD
:
996 /* Yay, the RR has been validated,
997 * return immediately, but fix up the expiry */
1001 *result
= one_result
;
1004 case DNSSEC_INVALID
:
1005 /* If the signature is invalid, let's try another
1006 key and/or signature. After all they
1007 key_tags and stuff are not unique, and
1008 might be shared by multiple keys. */
1009 found_invalid
= true;
1012 case DNSSEC_UNSUPPORTED_ALGORITHM
:
1013 /* If the key algorithm is
1014 unsupported, try another
1015 RRSIG/DNSKEY pair, but remember we
1016 encountered this, so that we can
1017 return a proper error when we
1018 encounter nothing better. */
1019 found_unsupported_algorithm
= true;
1022 case DNSSEC_SIGNATURE_EXPIRED
:
1023 /* If the signature is expired, try
1024 another one, but remember it, so
1025 that we can return this */
1026 found_expired_rrsig
= true;
1030 assert_not_reached("Unexpected DNSSEC validation result");
1035 if (found_expired_rrsig
)
1036 *result
= DNSSEC_SIGNATURE_EXPIRED
;
1037 else if (found_unsupported_algorithm
)
1038 *result
= DNSSEC_UNSUPPORTED_ALGORITHM
;
1039 else if (found_invalid
)
1040 *result
= DNSSEC_INVALID
;
1041 else if (found_rrsig
)
1042 *result
= DNSSEC_MISSING_KEY
;
1044 *result
= DNSSEC_NO_SIGNATURE
;
1052 int dnssec_has_rrsig(DnsAnswer
*a
, const DnsResourceKey
*key
) {
1053 DnsResourceRecord
*rr
;
1056 /* Checks whether there's at least one RRSIG in 'a' that protects RRs of the specified key */
1058 DNS_ANSWER_FOREACH(rr
, a
) {
1059 r
= dnssec_key_match_rrsig(key
, rr
);
1069 static int digest_to_gcrypt_md(uint8_t algorithm
) {
1071 /* Translates a DNSSEC digest algorithm into a gcrypt digest identifier */
1073 switch (algorithm
) {
1075 case DNSSEC_DIGEST_SHA1
:
1076 return GCRY_MD_SHA1
;
1078 case DNSSEC_DIGEST_SHA256
:
1079 return GCRY_MD_SHA256
;
1081 case DNSSEC_DIGEST_SHA384
:
1082 return GCRY_MD_SHA384
;
1089 int dnssec_verify_dnskey_by_ds(DnsResourceRecord
*dnskey
, DnsResourceRecord
*ds
, bool mask_revoke
) {
1090 uint8_t wire_format
[DNS_WIRE_FORMAT_HOSTNAME_MAX
];
1091 _cleanup_(gcry_md_closep
) gcry_md_hd_t md
= NULL
;
1094 int md_algorithm
, r
;
1100 /* Implements DNSKEY verification by a DS, according to RFC 4035, section 5.2 */
1102 if (dnskey
->key
->type
!= DNS_TYPE_DNSKEY
)
1104 if (ds
->key
->type
!= DNS_TYPE_DS
)
1106 if ((dnskey
->dnskey
.flags
& DNSKEY_FLAG_ZONE_KEY
) == 0)
1107 return -EKEYREJECTED
;
1108 if (!mask_revoke
&& (dnskey
->dnskey
.flags
& DNSKEY_FLAG_REVOKE
))
1109 return -EKEYREJECTED
;
1110 if (dnskey
->dnskey
.protocol
!= 3)
1111 return -EKEYREJECTED
;
1113 if (dnskey
->dnskey
.algorithm
!= ds
->ds
.algorithm
)
1115 if (dnssec_keytag(dnskey
, mask_revoke
) != ds
->ds
.key_tag
)
1118 initialize_libgcrypt(false);
1120 md_algorithm
= digest_to_gcrypt_md(ds
->ds
.digest_type
);
1121 if (md_algorithm
< 0)
1122 return md_algorithm
;
1124 hash_size
= gcry_md_get_algo_dlen(md_algorithm
);
1125 assert(hash_size
> 0);
1127 if (ds
->ds
.digest_size
!= hash_size
)
1130 r
= dns_name_to_wire_format(dns_resource_key_name(dnskey
->key
), wire_format
, sizeof(wire_format
), true);
1134 err
= gcry_md_open(&md
, md_algorithm
, 0);
1135 if (gcry_err_code(err
) != GPG_ERR_NO_ERROR
|| !md
)
1138 gcry_md_write(md
, wire_format
, r
);
1140 md_add_uint16(md
, dnskey
->dnskey
.flags
& ~DNSKEY_FLAG_REVOKE
);
1142 md_add_uint16(md
, dnskey
->dnskey
.flags
);
1143 md_add_uint8(md
, dnskey
->dnskey
.protocol
);
1144 md_add_uint8(md
, dnskey
->dnskey
.algorithm
);
1145 gcry_md_write(md
, dnskey
->dnskey
.key
, dnskey
->dnskey
.key_size
);
1147 result
= gcry_md_read(md
, 0);
1151 return memcmp(result
, ds
->ds
.digest
, ds
->ds
.digest_size
) == 0;
1154 int dnssec_verify_dnskey_by_ds_search(DnsResourceRecord
*dnskey
, DnsAnswer
*validated_ds
) {
1155 DnsResourceRecord
*ds
;
1156 DnsAnswerFlags flags
;
1161 if (dnskey
->key
->type
!= DNS_TYPE_DNSKEY
)
1164 DNS_ANSWER_FOREACH_FLAGS(ds
, flags
, validated_ds
) {
1166 if ((flags
& DNS_ANSWER_AUTHENTICATED
) == 0)
1169 if (ds
->key
->type
!= DNS_TYPE_DS
)
1171 if (ds
->key
->class != dnskey
->key
->class)
1174 r
= dns_name_equal(dns_resource_key_name(dnskey
->key
), dns_resource_key_name(ds
->key
));
1180 r
= dnssec_verify_dnskey_by_ds(dnskey
, ds
, false);
1181 if (IN_SET(r
, -EKEYREJECTED
, -EOPNOTSUPP
))
1182 return 0; /* The DNSKEY is revoked or otherwise invalid, or we don't support the digest algorithm */
1192 static int nsec3_hash_to_gcrypt_md(uint8_t algorithm
) {
1194 /* Translates a DNSSEC NSEC3 hash algorithm into a gcrypt digest identifier */
1196 switch (algorithm
) {
1198 case NSEC3_ALGORITHM_SHA1
:
1199 return GCRY_MD_SHA1
;
1206 int dnssec_nsec3_hash(DnsResourceRecord
*nsec3
, const char *name
, void *ret
) {
1207 uint8_t wire_format
[DNS_WIRE_FORMAT_HOSTNAME_MAX
];
1208 gcry_md_hd_t md
= NULL
;
1220 if (nsec3
->key
->type
!= DNS_TYPE_NSEC3
)
1223 if (nsec3
->nsec3
.iterations
> NSEC3_ITERATIONS_MAX
)
1224 return log_debug_errno(SYNTHETIC_ERRNO(EOPNOTSUPP
),
1225 "Ignoring NSEC3 RR %s with excessive number of iterations.",
1226 dns_resource_record_to_string(nsec3
));
1228 algorithm
= nsec3_hash_to_gcrypt_md(nsec3
->nsec3
.algorithm
);
1232 initialize_libgcrypt(false);
1234 hash_size
= gcry_md_get_algo_dlen(algorithm
);
1235 assert(hash_size
> 0);
1237 if (nsec3
->nsec3
.next_hashed_name_size
!= hash_size
)
1240 r
= dns_name_to_wire_format(name
, wire_format
, sizeof(wire_format
), true);
1244 err
= gcry_md_open(&md
, algorithm
, 0);
1245 if (gcry_err_code(err
) != GPG_ERR_NO_ERROR
|| !md
)
1248 gcry_md_write(md
, wire_format
, r
);
1249 gcry_md_write(md
, nsec3
->nsec3
.salt
, nsec3
->nsec3
.salt_size
);
1251 result
= gcry_md_read(md
, 0);
1257 for (k
= 0; k
< nsec3
->nsec3
.iterations
; k
++) {
1258 uint8_t tmp
[hash_size
];
1259 memcpy(tmp
, result
, hash_size
);
1262 gcry_md_write(md
, tmp
, hash_size
);
1263 gcry_md_write(md
, nsec3
->nsec3
.salt
, nsec3
->nsec3
.salt_size
);
1265 result
= gcry_md_read(md
, 0);
1272 memcpy(ret
, result
, hash_size
);
1273 r
= (int) hash_size
;
1280 static int nsec3_is_good(DnsResourceRecord
*rr
, DnsResourceRecord
*nsec3
) {
1286 if (rr
->key
->type
!= DNS_TYPE_NSEC3
)
1289 /* RFC 5155, Section 8.2 says we MUST ignore NSEC3 RRs with flags != 0 or 1 */
1290 if (!IN_SET(rr
->nsec3
.flags
, 0, 1))
1293 /* Ignore NSEC3 RRs whose algorithm we don't know */
1294 if (nsec3_hash_to_gcrypt_md(rr
->nsec3
.algorithm
) < 0)
1296 /* Ignore NSEC3 RRs with an excessive number of required iterations */
1297 if (rr
->nsec3
.iterations
> NSEC3_ITERATIONS_MAX
)
1300 /* Ignore NSEC3 RRs generated from wildcards. If these NSEC3 RRs weren't correctly signed we can't make this
1301 * check (since rr->n_skip_labels_source is -1), but that's OK, as we won't trust them anyway in that case. */
1302 if (!IN_SET(rr
->n_skip_labels_source
, 0, UINT_MAX
))
1304 /* Ignore NSEC3 RRs that are located anywhere else than one label below the zone */
1305 if (!IN_SET(rr
->n_skip_labels_signer
, 1, UINT_MAX
))
1311 /* If a second NSEC3 RR is specified, also check if they are from the same zone. */
1313 if (nsec3
== rr
) /* Shortcut */
1316 if (rr
->key
->class != nsec3
->key
->class)
1318 if (rr
->nsec3
.algorithm
!= nsec3
->nsec3
.algorithm
)
1320 if (rr
->nsec3
.iterations
!= nsec3
->nsec3
.iterations
)
1322 if (rr
->nsec3
.salt_size
!= nsec3
->nsec3
.salt_size
)
1324 if (memcmp_safe(rr
->nsec3
.salt
, nsec3
->nsec3
.salt
, rr
->nsec3
.salt_size
) != 0)
1327 a
= dns_resource_key_name(rr
->key
);
1328 r
= dns_name_parent(&a
); /* strip off hash */
1332 b
= dns_resource_key_name(nsec3
->key
);
1333 r
= dns_name_parent(&b
); /* strip off hash */
1337 /* Make sure both have the same parent */
1338 return dns_name_equal(a
, b
);
1341 static int nsec3_hashed_domain_format(const uint8_t *hashed
, size_t hashed_size
, const char *zone
, char **ret
) {
1342 _cleanup_free_
char *l
= NULL
;
1346 assert(hashed_size
> 0);
1350 l
= base32hexmem(hashed
, hashed_size
, false);
1354 j
= strjoin(l
, ".", zone
);
1359 return (int) hashed_size
;
1362 static int nsec3_hashed_domain_make(DnsResourceRecord
*nsec3
, const char *domain
, const char *zone
, char **ret
) {
1363 uint8_t hashed
[DNSSEC_HASH_SIZE_MAX
];
1371 hashed_size
= dnssec_nsec3_hash(nsec3
, domain
, hashed
);
1372 if (hashed_size
< 0)
1375 return nsec3_hashed_domain_format(hashed
, (size_t) hashed_size
, zone
, ret
);
1378 /* See RFC 5155, Section 8
1379 * First try to find a NSEC3 record that matches our query precisely, if that fails, find the closest
1380 * enclosure. Secondly, find a proof that there is no closer enclosure and either a proof that there
1381 * is no wildcard domain as a direct descendant of the closest enclosure, or find an NSEC3 record that
1382 * matches the wildcard domain.
1384 * Based on this we can prove either the existence of the record in @key, or NXDOMAIN or NODATA, or
1385 * that there is no proof either way. The latter is the case if a proof of non-existence of a given
1386 * name uses an NSEC3 record with the opt-out bit set. Lastly, if we are given insufficient NSEC3 records
1387 * to conclude anything we indicate this by returning NO_RR. */
1388 static int dnssec_test_nsec3(DnsAnswer
*answer
, DnsResourceKey
*key
, DnssecNsecResult
*result
, bool *authenticated
, uint32_t *ttl
) {
1389 _cleanup_free_
char *next_closer_domain
= NULL
, *wildcard_domain
= NULL
;
1390 const char *zone
, *p
, *pp
= NULL
, *wildcard
;
1391 DnsResourceRecord
*rr
, *enclosure_rr
, *zone_rr
, *wildcard_rr
= NULL
;
1392 DnsAnswerFlags flags
;
1394 bool a
, no_closer
= false, no_wildcard
= false, optout
= false;
1399 /* First step, find the zone name and the NSEC3 parameters of the zone.
1400 * it is sufficient to look for the longest common suffix we find with
1401 * any NSEC3 RR in the response. Any NSEC3 record will do as all NSEC3
1402 * records from a given zone in a response must use the same
1404 zone
= dns_resource_key_name(key
);
1406 DNS_ANSWER_FOREACH_FLAGS(zone_rr
, flags
, answer
) {
1407 r
= nsec3_is_good(zone_rr
, NULL
);
1413 r
= dns_name_equal_skip(dns_resource_key_name(zone_rr
->key
), 1, zone
);
1420 /* Strip one label from the front */
1421 r
= dns_name_parent(&zone
);
1428 *result
= DNSSEC_NSEC_NO_RR
;
1432 /* Second step, find the closest encloser NSEC3 RR in 'answer' that matches 'key' */
1433 p
= dns_resource_key_name(key
);
1435 _cleanup_free_
char *hashed_domain
= NULL
;
1437 hashed_size
= nsec3_hashed_domain_make(zone_rr
, p
, zone
, &hashed_domain
);
1438 if (hashed_size
== -EOPNOTSUPP
) {
1439 *result
= DNSSEC_NSEC_UNSUPPORTED_ALGORITHM
;
1442 if (hashed_size
< 0)
1445 DNS_ANSWER_FOREACH_FLAGS(enclosure_rr
, flags
, answer
) {
1447 r
= nsec3_is_good(enclosure_rr
, zone_rr
);
1453 if (enclosure_rr
->nsec3
.next_hashed_name_size
!= (size_t) hashed_size
)
1456 r
= dns_name_equal(dns_resource_key_name(enclosure_rr
->key
), hashed_domain
);
1460 a
= flags
& DNS_ANSWER_AUTHENTICATED
;
1461 goto found_closest_encloser
;
1465 /* We didn't find the closest encloser with this name,
1466 * but let's remember this domain name, it might be
1467 * the next closer name */
1471 /* Strip one label from the front */
1472 r
= dns_name_parent(&p
);
1479 *result
= DNSSEC_NSEC_NO_RR
;
1482 found_closest_encloser
:
1483 /* We found a closest encloser in 'p'; next closer is 'pp' */
1486 /* We have an exact match! If we area looking for a DS RR, then we must insist that we got the NSEC3 RR
1487 * from the parent. Otherwise the one from the child. Do so, by checking whether SOA and NS are
1488 * appropriately set. */
1490 if (key
->type
== DNS_TYPE_DS
) {
1491 if (bitmap_isset(enclosure_rr
->nsec3
.types
, DNS_TYPE_SOA
))
1494 if (bitmap_isset(enclosure_rr
->nsec3
.types
, DNS_TYPE_NS
) &&
1495 !bitmap_isset(enclosure_rr
->nsec3
.types
, DNS_TYPE_SOA
))
1499 /* No next closer NSEC3 RR. That means there's a direct NSEC3 RR for our key. */
1500 if (bitmap_isset(enclosure_rr
->nsec3
.types
, key
->type
))
1501 *result
= DNSSEC_NSEC_FOUND
;
1502 else if (bitmap_isset(enclosure_rr
->nsec3
.types
, DNS_TYPE_CNAME
))
1503 *result
= DNSSEC_NSEC_CNAME
;
1505 *result
= DNSSEC_NSEC_NODATA
;
1510 *ttl
= enclosure_rr
->ttl
;
1515 /* Ensure this is not a DNAME domain, see RFC5155, section 8.3. */
1516 if (bitmap_isset(enclosure_rr
->nsec3
.types
, DNS_TYPE_DNAME
))
1519 /* Ensure that this data is from the delegated domain
1520 * (i.e. originates from the "lower" DNS server), and isn't
1521 * just glue records (i.e. doesn't originate from the "upper"
1523 if (bitmap_isset(enclosure_rr
->nsec3
.types
, DNS_TYPE_NS
) &&
1524 !bitmap_isset(enclosure_rr
->nsec3
.types
, DNS_TYPE_SOA
))
1527 /* Prove that there is no next closer and whether or not there is a wildcard domain. */
1529 wildcard
= strjoina("*.", p
);
1530 r
= nsec3_hashed_domain_make(enclosure_rr
, wildcard
, zone
, &wildcard_domain
);
1533 if (r
!= hashed_size
)
1536 r
= nsec3_hashed_domain_make(enclosure_rr
, pp
, zone
, &next_closer_domain
);
1539 if (r
!= hashed_size
)
1542 DNS_ANSWER_FOREACH_FLAGS(rr
, flags
, answer
) {
1543 _cleanup_free_
char *next_hashed_domain
= NULL
;
1545 r
= nsec3_is_good(rr
, zone_rr
);
1551 r
= nsec3_hashed_domain_format(rr
->nsec3
.next_hashed_name
, rr
->nsec3
.next_hashed_name_size
, zone
, &next_hashed_domain
);
1555 r
= dns_name_between(dns_resource_key_name(rr
->key
), next_closer_domain
, next_hashed_domain
);
1559 if (rr
->nsec3
.flags
& 1)
1562 a
= a
&& (flags
& DNS_ANSWER_AUTHENTICATED
);
1567 r
= dns_name_equal(dns_resource_key_name(rr
->key
), wildcard_domain
);
1571 a
= a
&& (flags
& DNS_ANSWER_AUTHENTICATED
);
1576 r
= dns_name_between(dns_resource_key_name(rr
->key
), wildcard_domain
, next_hashed_domain
);
1580 if (rr
->nsec3
.flags
& 1)
1581 /* This only makes sense if we have a wildcard delegation, which is
1582 * very unlikely, see RFC 4592, Section 4.2, but we cannot rely on
1583 * this not happening, so hence cannot simply conclude NXDOMAIN as
1587 a
= a
&& (flags
& DNS_ANSWER_AUTHENTICATED
);
1593 if (wildcard_rr
&& no_wildcard
)
1597 *result
= DNSSEC_NSEC_NO_RR
;
1602 /* A wildcard exists that matches our query. */
1604 /* This is not specified in any RFC to the best of my knowledge, but
1605 * if the next closer enclosure is covered by an opt-out NSEC3 RR
1606 * it means that we cannot prove that the source of synthesis is
1607 * correct, as there may be a closer match. */
1608 *result
= DNSSEC_NSEC_OPTOUT
;
1609 else if (bitmap_isset(wildcard_rr
->nsec3
.types
, key
->type
))
1610 *result
= DNSSEC_NSEC_FOUND
;
1611 else if (bitmap_isset(wildcard_rr
->nsec3
.types
, DNS_TYPE_CNAME
))
1612 *result
= DNSSEC_NSEC_CNAME
;
1614 *result
= DNSSEC_NSEC_NODATA
;
1617 /* The RFC only specifies that we have to care for optout for NODATA for
1618 * DS records. However, children of an insecure opt-out delegation should
1619 * also be considered opt-out, rather than verified NXDOMAIN.
1620 * Note that we do not require a proof of wildcard non-existence if the
1621 * next closer domain is covered by an opt-out, as that would not provide
1622 * any additional information. */
1623 *result
= DNSSEC_NSEC_OPTOUT
;
1624 else if (no_wildcard
)
1625 *result
= DNSSEC_NSEC_NXDOMAIN
;
1627 *result
= DNSSEC_NSEC_NO_RR
;
1637 *ttl
= enclosure_rr
->ttl
;
1642 static int dnssec_nsec_wildcard_equal(DnsResourceRecord
*rr
, const char *name
) {
1643 char label
[DNS_LABEL_MAX
];
1648 assert(rr
->key
->type
== DNS_TYPE_NSEC
);
1650 /* Checks whether the specified RR has a name beginning in "*.", and if the rest is a suffix of our name */
1652 if (rr
->n_skip_labels_source
!= 1)
1655 n
= dns_resource_key_name(rr
->key
);
1656 r
= dns_label_unescape(&n
, label
, sizeof label
, 0);
1659 if (r
!= 1 || label
[0] != '*')
1662 return dns_name_endswith(name
, n
);
1665 static int dnssec_nsec_in_path(DnsResourceRecord
*rr
, const char *name
) {
1666 const char *nn
, *common_suffix
;
1670 assert(rr
->key
->type
== DNS_TYPE_NSEC
);
1672 /* Checks whether the specified nsec RR indicates that name is an empty non-terminal (ENT)
1674 * A couple of examples:
1676 * NSEC bar → waldo.foo.bar: indicates that foo.bar exists and is an ENT
1677 * NSEC waldo.foo.bar → yyy.zzz.xoo.bar: indicates that xoo.bar and zzz.xoo.bar exist and are ENTs
1678 * NSEC yyy.zzz.xoo.bar → bar: indicates pretty much nothing about ENTs
1681 /* First, determine parent of next domain. */
1682 nn
= rr
->nsec
.next_domain_name
;
1683 r
= dns_name_parent(&nn
);
1687 /* If the name we just determined is not equal or child of the name we are interested in, then we can't say
1688 * anything at all. */
1689 r
= dns_name_endswith(nn
, name
);
1693 /* If the name we are interested in is not a prefix of the common suffix of the NSEC RR's owner and next domain names, then we can't say anything either. */
1694 r
= dns_name_common_suffix(dns_resource_key_name(rr
->key
), rr
->nsec
.next_domain_name
, &common_suffix
);
1698 return dns_name_endswith(name
, common_suffix
);
1701 static int dnssec_nsec_from_parent_zone(DnsResourceRecord
*rr
, const char *name
) {
1705 assert(rr
->key
->type
== DNS_TYPE_NSEC
);
1707 /* Checks whether this NSEC originates to the parent zone or the child zone. */
1709 r
= dns_name_parent(&name
);
1713 r
= dns_name_equal(name
, dns_resource_key_name(rr
->key
));
1717 /* DNAME, and NS without SOA is an indication for a delegation. */
1718 if (bitmap_isset(rr
->nsec
.types
, DNS_TYPE_DNAME
))
1721 if (bitmap_isset(rr
->nsec
.types
, DNS_TYPE_NS
) && !bitmap_isset(rr
->nsec
.types
, DNS_TYPE_SOA
))
1727 static int dnssec_nsec_covers(DnsResourceRecord
*rr
, const char *name
) {
1732 assert(rr
->key
->type
== DNS_TYPE_NSEC
);
1734 /* Checks whether the name is covered by this NSEC RR. This means, that the name is somewhere below the NSEC's
1735 * signer name, and between the NSEC's two names. */
1737 r
= dns_resource_record_signer(rr
, &signer
);
1741 r
= dns_name_endswith(name
, signer
); /* this NSEC isn't suitable the name is not in the signer's domain */
1745 return dns_name_between(dns_resource_key_name(rr
->key
), name
, rr
->nsec
.next_domain_name
);
1748 static int dnssec_nsec_generate_wildcard(DnsResourceRecord
*rr
, const char *name
, char **wc
) {
1749 const char *common_suffix1
, *common_suffix2
, *signer
;
1750 int r
, labels1
, labels2
;
1753 assert(rr
->key
->type
== DNS_TYPE_NSEC
);
1755 /* Generates "Wildcard at the Closest Encloser" for the given name and NSEC RR. */
1757 r
= dns_resource_record_signer(rr
, &signer
);
1761 r
= dns_name_endswith(name
, signer
); /* this NSEC isn't suitable the name is not in the signer's domain */
1765 r
= dns_name_common_suffix(name
, dns_resource_key_name(rr
->key
), &common_suffix1
);
1769 r
= dns_name_common_suffix(name
, rr
->nsec
.next_domain_name
, &common_suffix2
);
1773 labels1
= dns_name_count_labels(common_suffix1
);
1777 labels2
= dns_name_count_labels(common_suffix2
);
1781 if (labels1
> labels2
)
1782 r
= dns_name_concat("*", common_suffix1
, 0, wc
);
1784 r
= dns_name_concat("*", common_suffix2
, 0, wc
);
1792 int dnssec_nsec_test(DnsAnswer
*answer
, DnsResourceKey
*key
, DnssecNsecResult
*result
, bool *authenticated
, uint32_t *ttl
) {
1793 bool have_nsec3
= false, covering_rr_authenticated
= false, wildcard_rr_authenticated
= false;
1794 DnsResourceRecord
*rr
, *covering_rr
= NULL
, *wildcard_rr
= NULL
;
1795 DnsAnswerFlags flags
;
1802 /* Look for any NSEC/NSEC3 RRs that say something about the specified key. */
1804 name
= dns_resource_key_name(key
);
1806 DNS_ANSWER_FOREACH_FLAGS(rr
, flags
, answer
) {
1808 if (rr
->key
->class != key
->class)
1811 have_nsec3
= have_nsec3
|| (rr
->key
->type
== DNS_TYPE_NSEC3
);
1813 if (rr
->key
->type
!= DNS_TYPE_NSEC
)
1816 /* The following checks only make sense for NSEC RRs that are not expanded from a wildcard */
1817 r
= dns_resource_record_is_synthetic(rr
);
1818 if (r
== -ENODATA
) /* No signing RR known. */
1825 /* Check if this is a direct match. If so, we have encountered a NODATA case */
1826 r
= dns_name_equal(dns_resource_key_name(rr
->key
), name
);
1830 /* If it's not a direct match, maybe it's a wild card match? */
1831 r
= dnssec_nsec_wildcard_equal(rr
, name
);
1836 if (key
->type
== DNS_TYPE_DS
) {
1837 /* If we look for a DS RR and the server sent us the NSEC RR of the child zone
1838 * we have a problem. For DS RRs we want the NSEC RR from the parent */
1839 if (bitmap_isset(rr
->nsec
.types
, DNS_TYPE_SOA
))
1842 /* For all RR types, ensure that if NS is set SOA is set too, so that we know
1843 * we got the child's NSEC. */
1844 if (bitmap_isset(rr
->nsec
.types
, DNS_TYPE_NS
) &&
1845 !bitmap_isset(rr
->nsec
.types
, DNS_TYPE_SOA
))
1849 if (bitmap_isset(rr
->nsec
.types
, key
->type
))
1850 *result
= DNSSEC_NSEC_FOUND
;
1851 else if (bitmap_isset(rr
->nsec
.types
, DNS_TYPE_CNAME
))
1852 *result
= DNSSEC_NSEC_CNAME
;
1854 *result
= DNSSEC_NSEC_NODATA
;
1857 *authenticated
= flags
& DNS_ANSWER_AUTHENTICATED
;
1864 /* Check if the name we are looking for is an empty non-terminal within the owner or next name
1865 * of the NSEC RR. */
1866 r
= dnssec_nsec_in_path(rr
, name
);
1870 *result
= DNSSEC_NSEC_NODATA
;
1873 *authenticated
= flags
& DNS_ANSWER_AUTHENTICATED
;
1880 /* The following two "covering" checks, are not useful if the NSEC is from the parent */
1881 r
= dnssec_nsec_from_parent_zone(rr
, name
);
1887 /* Check if this NSEC RR proves the absence of an explicit RR under this name */
1888 r
= dnssec_nsec_covers(rr
, name
);
1891 if (r
> 0 && (!covering_rr
|| !covering_rr_authenticated
)) {
1893 covering_rr_authenticated
= flags
& DNS_ANSWER_AUTHENTICATED
;
1898 _cleanup_free_
char *wc
= NULL
;
1899 r
= dnssec_nsec_generate_wildcard(covering_rr
, name
, &wc
);
1903 DNS_ANSWER_FOREACH_FLAGS(rr
, flags
, answer
) {
1905 if (rr
->key
->class != key
->class)
1908 if (rr
->key
->type
!= DNS_TYPE_NSEC
)
1911 /* Check if this NSEC RR proves the nonexistence of the wildcard */
1912 r
= dnssec_nsec_covers(rr
, wc
);
1915 if (r
> 0 && (!wildcard_rr
|| !wildcard_rr_authenticated
)) {
1917 wildcard_rr_authenticated
= flags
& DNS_ANSWER_AUTHENTICATED
;
1922 if (covering_rr
&& wildcard_rr
) {
1923 /* If we could prove that neither the name itself, nor the wildcard at the closest encloser exists, we
1924 * proved the NXDOMAIN case. */
1925 *result
= DNSSEC_NSEC_NXDOMAIN
;
1928 *authenticated
= covering_rr_authenticated
&& wildcard_rr_authenticated
;
1930 *ttl
= MIN(covering_rr
->ttl
, wildcard_rr
->ttl
);
1935 /* OK, this was not sufficient. Let's see if NSEC3 can help. */
1937 return dnssec_test_nsec3(answer
, key
, result
, authenticated
, ttl
);
1939 /* No appropriate NSEC RR found, report this. */
1940 *result
= DNSSEC_NSEC_NO_RR
;
1944 static int dnssec_nsec_test_enclosed(DnsAnswer
*answer
, uint16_t type
, const char *name
, const char *zone
, bool *authenticated
) {
1945 DnsResourceRecord
*rr
;
1946 DnsAnswerFlags flags
;
1952 /* Checks whether there's an NSEC/NSEC3 that proves that the specified 'name' is non-existing in the specified
1953 * 'zone'. The 'zone' must be a suffix of the 'name'. */
1955 DNS_ANSWER_FOREACH_FLAGS(rr
, flags
, answer
) {
1958 if (rr
->key
->type
!= type
&& type
!= DNS_TYPE_ANY
)
1961 switch (rr
->key
->type
) {
1965 /* We only care for NSEC RRs from the indicated zone */
1966 r
= dns_resource_record_is_signer(rr
, zone
);
1972 r
= dns_name_between(dns_resource_key_name(rr
->key
), name
, rr
->nsec
.next_domain_name
);
1979 case DNS_TYPE_NSEC3
: {
1980 _cleanup_free_
char *hashed_domain
= NULL
, *next_hashed_domain
= NULL
;
1982 /* We only care for NSEC3 RRs from the indicated zone */
1983 r
= dns_resource_record_is_signer(rr
, zone
);
1989 r
= nsec3_is_good(rr
, NULL
);
1995 /* Format the domain we are testing with the NSEC3 RR's hash function */
1996 r
= nsec3_hashed_domain_make(
2003 if ((size_t) r
!= rr
->nsec3
.next_hashed_name_size
)
2006 /* Format the NSEC3's next hashed name as proper domain name */
2007 r
= nsec3_hashed_domain_format(
2008 rr
->nsec3
.next_hashed_name
,
2009 rr
->nsec3
.next_hashed_name_size
,
2011 &next_hashed_domain
);
2015 r
= dns_name_between(dns_resource_key_name(rr
->key
), hashed_domain
, next_hashed_domain
);
2029 *authenticated
= flags
& DNS_ANSWER_AUTHENTICATED
;
2037 static int dnssec_test_positive_wildcard_nsec3(
2042 bool *authenticated
) {
2044 const char *next_closer
= NULL
;
2047 /* Run a positive NSEC3 wildcard proof. Specifically:
2049 * A proof that the "next closer" of the generating wildcard does not exist.
2051 * Note a key difference between the NSEC3 and NSEC versions of the proof. NSEC RRs don't have to exist for
2052 * empty non-transients. NSEC3 RRs however have to. This means it's sufficient to check if the next closer name
2053 * exists for the NSEC3 RR and we are done.
2055 * To prove that a.b.c.d.e.f is rightfully synthesized from a wildcard *.d.e.f all we have to check is that
2056 * c.d.e.f does not exist. */
2060 r
= dns_name_parent(&name
);
2064 r
= dns_name_equal(name
, source
);
2071 return dnssec_nsec_test_enclosed(answer
, DNS_TYPE_NSEC3
, next_closer
, zone
, authenticated
);
2074 static int dnssec_test_positive_wildcard_nsec(
2079 bool *_authenticated
) {
2081 bool authenticated
= true;
2084 /* Run a positive NSEC wildcard proof. Specifically:
2086 * A proof that there's neither a wildcard name nor a non-wildcard name that is a suffix of the name "name" and
2087 * a prefix of the synthesizing source "source" in the zone "zone".
2089 * See RFC 5155, Section 8.8 and RFC 4035, Section 5.3.4
2091 * Note that if we want to prove that a.b.c.d.e.f is rightfully synthesized from a wildcard *.d.e.f, then we
2092 * have to prove that none of the following exist:
2102 _cleanup_free_
char *wc
= NULL
;
2105 /* Check if there's an NSEC or NSEC3 RR that proves that the mame we determined is really non-existing,
2106 * i.e between the owner name and the next name of an NSEC RR. */
2107 r
= dnssec_nsec_test_enclosed(answer
, DNS_TYPE_NSEC
, name
, zone
, &a
);
2111 authenticated
= authenticated
&& a
;
2113 /* Strip one label off */
2114 r
= dns_name_parent(&name
);
2118 /* Did we reach the source of synthesis? */
2119 r
= dns_name_equal(name
, source
);
2123 /* Successful exit */
2124 *_authenticated
= authenticated
;
2128 /* Safety check, that the source of synthesis is still our suffix */
2129 r
= dns_name_endswith(name
, source
);
2135 /* Replace the label we stripped off with an asterisk */
2136 wc
= strjoin("*.", name
);
2140 /* And check if the proof holds for the asterisk name, too */
2141 r
= dnssec_nsec_test_enclosed(answer
, DNS_TYPE_NSEC
, wc
, zone
, &a
);
2145 authenticated
= authenticated
&& a
;
2146 /* In the next iteration we'll check the non-asterisk-prefixed version */
2150 int dnssec_test_positive_wildcard(
2155 bool *authenticated
) {
2162 assert(authenticated
);
2164 r
= dns_answer_contains_zone_nsec3(answer
, zone
);
2168 return dnssec_test_positive_wildcard_nsec3(answer
, name
, source
, zone
, authenticated
);
2170 return dnssec_test_positive_wildcard_nsec(answer
, name
, source
, zone
, authenticated
);
2175 int dnssec_verify_rrset(
2177 const DnsResourceKey
*key
,
2178 DnsResourceRecord
*rrsig
,
2179 DnsResourceRecord
*dnskey
,
2181 DnssecResult
*result
) {
2186 int dnssec_rrsig_match_dnskey(DnsResourceRecord
*rrsig
, DnsResourceRecord
*dnskey
, bool revoked_ok
) {
2191 int dnssec_key_match_rrsig(const DnsResourceKey
*key
, DnsResourceRecord
*rrsig
) {
2196 int dnssec_verify_rrset_search(
2198 const DnsResourceKey
*key
,
2199 DnsAnswer
*validated_dnskeys
,
2201 DnssecResult
*result
,
2202 DnsResourceRecord
**ret_rrsig
) {
2207 int dnssec_has_rrsig(DnsAnswer
*a
, const DnsResourceKey
*key
) {
2212 int dnssec_verify_dnskey_by_ds(DnsResourceRecord
*dnskey
, DnsResourceRecord
*ds
, bool mask_revoke
) {
2217 int dnssec_verify_dnskey_by_ds_search(DnsResourceRecord
*dnskey
, DnsAnswer
*validated_ds
) {
2222 int dnssec_nsec3_hash(DnsResourceRecord
*nsec3
, const char *name
, void *ret
) {
2227 int dnssec_nsec_test(DnsAnswer
*answer
, DnsResourceKey
*key
, DnssecNsecResult
*result
, bool *authenticated
, uint32_t *ttl
) {
2232 int dnssec_test_positive_wildcard(
2237 bool *authenticated
) {
2244 static const char* const dnssec_result_table
[_DNSSEC_RESULT_MAX
] = {
2245 [DNSSEC_VALIDATED
] = "validated",
2246 [DNSSEC_VALIDATED_WILDCARD
] = "validated-wildcard",
2247 [DNSSEC_INVALID
] = "invalid",
2248 [DNSSEC_SIGNATURE_EXPIRED
] = "signature-expired",
2249 [DNSSEC_UNSUPPORTED_ALGORITHM
] = "unsupported-algorithm",
2250 [DNSSEC_NO_SIGNATURE
] = "no-signature",
2251 [DNSSEC_MISSING_KEY
] = "missing-key",
2252 [DNSSEC_UNSIGNED
] = "unsigned",
2253 [DNSSEC_FAILED_AUXILIARY
] = "failed-auxiliary",
2254 [DNSSEC_NSEC_MISMATCH
] = "nsec-mismatch",
2255 [DNSSEC_INCOMPATIBLE_SERVER
] = "incompatible-server",
2257 DEFINE_STRING_TABLE_LOOKUP(dnssec_result
, DnssecResult
);
2259 static const char* const dnssec_verdict_table
[_DNSSEC_VERDICT_MAX
] = {
2260 [DNSSEC_SECURE
] = "secure",
2261 [DNSSEC_INSECURE
] = "insecure",
2262 [DNSSEC_BOGUS
] = "bogus",
2263 [DNSSEC_INDETERMINATE
] = "indeterminate",
2265 DEFINE_STRING_TABLE_LOOKUP(dnssec_verdict
, DnssecVerdict
);