1 /* SPDX-License-Identifier: LGPL-2.1+ */
9 #include "alloc-util.h"
10 #include "dns-domain.h"
13 #include "gcrypt-util.h"
14 #include "hexdecoct.h"
15 #include "resolved-dns-dnssec.h"
16 #include "resolved-dns-packet.h"
17 #include "string-table.h"
19 #define VERIFY_RRS_MAX 256
20 #define MAX_KEY_SIZE (32*1024)
22 /* Permit a maximum clock skew of 1h 10min. This should be enough to deal with DST confusion */
23 #define SKEW_MAX (1*USEC_PER_HOUR + 10*USEC_PER_MINUTE)
25 /* Maximum number of NSEC3 iterations we'll do. RFC5155 says 2500 shall be the maximum useful value */
26 #define NSEC3_ITERATIONS_MAX 2500
29 * The DNSSEC Chain of trust:
31 * Normal RRs are protected via RRSIG RRs in combination with DNSKEY RRs, all in the same zone
32 * DNSKEY RRs are either protected like normal RRs, or via a DS from a zone "higher" up the tree
33 * DS RRs are protected like normal RRs
36 * Normal RR → RRSIG/DNSKEY+ → DS → RRSIG/DNSKEY+ → DS → ... → DS → RRSIG/DNSKEY+ → DS
39 uint16_t dnssec_keytag(DnsResourceRecord
*dnskey
, bool mask_revoke
) {
44 /* The algorithm from RFC 4034, Appendix B. */
47 assert(dnskey
->key
->type
== DNS_TYPE_DNSKEY
);
49 f
= (uint32_t) dnskey
->dnskey
.flags
;
52 f
&= ~DNSKEY_FLAG_REVOKE
;
54 sum
= f
+ ((((uint32_t) dnskey
->dnskey
.protocol
) << 8) + (uint32_t) dnskey
->dnskey
.algorithm
);
56 p
= dnskey
->dnskey
.key
;
58 for (i
= 0; i
< dnskey
->dnskey
.key_size
; i
++)
59 sum
+= (i
& 1) == 0 ? (uint32_t) p
[i
] << 8 : (uint32_t) p
[i
];
61 sum
+= (sum
>> 16) & UINT32_C(0xFFFF);
63 return sum
& UINT32_C(0xFFFF);
66 int dnssec_canonicalize(const char *n
, char *buffer
, size_t buffer_max
) {
70 /* Converts the specified hostname into DNSSEC canonicalized
77 r
= dns_label_unescape(&n
, buffer
, buffer_max
);
83 if (buffer_max
< (size_t) r
+ 2)
86 /* The DNSSEC canonical form is not clear on what to
87 * do with dots appearing in labels, the way DNS-SD
88 * does it. Refuse it for now. */
90 if (memchr(buffer
, '.', r
))
93 ascii_strlower_n(buffer
, (size_t) r
);
103 /* Not even a single label: this is the root domain name */
105 assert(buffer_max
> 2);
117 static int rr_compare(DnsResourceRecord
* const *a
, DnsResourceRecord
* const *b
) {
118 const DnsResourceRecord
*x
= *a
, *y
= *b
;
122 /* Let's order the RRs according to RFC 4034, Section 6.3 */
125 assert(x
->wire_format
);
127 assert(y
->wire_format
);
129 m
= MIN(DNS_RESOURCE_RECORD_RDATA_SIZE(x
), DNS_RESOURCE_RECORD_RDATA_SIZE(y
));
131 r
= memcmp(DNS_RESOURCE_RECORD_RDATA(x
), DNS_RESOURCE_RECORD_RDATA(y
), m
);
135 return CMP(DNS_RESOURCE_RECORD_RDATA_SIZE(x
), DNS_RESOURCE_RECORD_RDATA_SIZE(y
));
138 static int dnssec_rsa_verify_raw(
139 const char *hash_algorithm
,
140 const void *signature
, size_t signature_size
,
141 const void *data
, size_t data_size
,
142 const void *exponent
, size_t exponent_size
,
143 const void *modulus
, size_t modulus_size
) {
145 gcry_sexp_t public_key_sexp
= NULL
, data_sexp
= NULL
, signature_sexp
= NULL
;
146 gcry_mpi_t n
= NULL
, e
= NULL
, s
= NULL
;
150 assert(hash_algorithm
);
152 ge
= gcry_mpi_scan(&s
, GCRYMPI_FMT_USG
, signature
, signature_size
, NULL
);
158 ge
= gcry_mpi_scan(&e
, GCRYMPI_FMT_USG
, exponent
, exponent_size
, NULL
);
164 ge
= gcry_mpi_scan(&n
, GCRYMPI_FMT_USG
, modulus
, modulus_size
, NULL
);
170 ge
= gcry_sexp_build(&signature_sexp
,
172 "(sig-val (rsa (s %m)))",
180 ge
= gcry_sexp_build(&data_sexp
,
182 "(data (flags pkcs1) (hash %s %b))",
191 ge
= gcry_sexp_build(&public_key_sexp
,
193 "(public-key (rsa (n %m) (e %m)))",
201 ge
= gcry_pk_verify(signature_sexp
, data_sexp
, public_key_sexp
);
202 if (gpg_err_code(ge
) == GPG_ERR_BAD_SIGNATURE
)
205 log_debug("RSA signature check failed: %s", gpg_strerror(ge
));
219 gcry_sexp_release(public_key_sexp
);
221 gcry_sexp_release(signature_sexp
);
223 gcry_sexp_release(data_sexp
);
228 static int dnssec_rsa_verify(
229 const char *hash_algorithm
,
230 const void *hash
, size_t hash_size
,
231 DnsResourceRecord
*rrsig
,
232 DnsResourceRecord
*dnskey
) {
234 size_t exponent_size
, modulus_size
;
235 void *exponent
, *modulus
;
237 assert(hash_algorithm
);
239 assert(hash_size
> 0);
243 if (*(uint8_t*) dnskey
->dnskey
.key
== 0) {
244 /* exponent is > 255 bytes long */
246 exponent
= (uint8_t*) dnskey
->dnskey
.key
+ 3;
248 ((size_t) (((uint8_t*) dnskey
->dnskey
.key
)[1]) << 8) |
249 ((size_t) ((uint8_t*) dnskey
->dnskey
.key
)[2]);
251 if (exponent_size
< 256)
254 if (3 + exponent_size
>= dnskey
->dnskey
.key_size
)
257 modulus
= (uint8_t*) dnskey
->dnskey
.key
+ 3 + exponent_size
;
258 modulus_size
= dnskey
->dnskey
.key_size
- 3 - exponent_size
;
261 /* exponent is <= 255 bytes long */
263 exponent
= (uint8_t*) dnskey
->dnskey
.key
+ 1;
264 exponent_size
= (size_t) ((uint8_t*) dnskey
->dnskey
.key
)[0];
266 if (exponent_size
<= 0)
269 if (1 + exponent_size
>= dnskey
->dnskey
.key_size
)
272 modulus
= (uint8_t*) dnskey
->dnskey
.key
+ 1 + exponent_size
;
273 modulus_size
= dnskey
->dnskey
.key_size
- 1 - exponent_size
;
276 return dnssec_rsa_verify_raw(
278 rrsig
->rrsig
.signature
, rrsig
->rrsig
.signature_size
,
280 exponent
, exponent_size
,
281 modulus
, modulus_size
);
284 static int dnssec_ecdsa_verify_raw(
285 const char *hash_algorithm
,
287 const void *signature_r
, size_t signature_r_size
,
288 const void *signature_s
, size_t signature_s_size
,
289 const void *data
, size_t data_size
,
290 const void *key
, size_t key_size
) {
292 gcry_sexp_t public_key_sexp
= NULL
, data_sexp
= NULL
, signature_sexp
= NULL
;
293 gcry_mpi_t q
= NULL
, r
= NULL
, s
= NULL
;
297 assert(hash_algorithm
);
299 ge
= gcry_mpi_scan(&r
, GCRYMPI_FMT_USG
, signature_r
, signature_r_size
, NULL
);
305 ge
= gcry_mpi_scan(&s
, GCRYMPI_FMT_USG
, signature_s
, signature_s_size
, NULL
);
311 ge
= gcry_mpi_scan(&q
, GCRYMPI_FMT_USG
, key
, key_size
, NULL
);
317 ge
= gcry_sexp_build(&signature_sexp
,
319 "(sig-val (ecdsa (r %m) (s %m)))",
327 ge
= gcry_sexp_build(&data_sexp
,
329 "(data (flags rfc6979) (hash %s %b))",
338 ge
= gcry_sexp_build(&public_key_sexp
,
340 "(public-key (ecc (curve %s) (q %m)))",
348 ge
= gcry_pk_verify(signature_sexp
, data_sexp
, public_key_sexp
);
349 if (gpg_err_code(ge
) == GPG_ERR_BAD_SIGNATURE
)
352 log_debug("ECDSA signature check failed: %s", gpg_strerror(ge
));
365 gcry_sexp_release(public_key_sexp
);
367 gcry_sexp_release(signature_sexp
);
369 gcry_sexp_release(data_sexp
);
374 static int dnssec_ecdsa_verify(
375 const char *hash_algorithm
,
377 const void *hash
, size_t hash_size
,
378 DnsResourceRecord
*rrsig
,
379 DnsResourceRecord
*dnskey
) {
390 if (algorithm
== DNSSEC_ALGORITHM_ECDSAP256SHA256
) {
392 curve
= "NIST P-256";
393 } else if (algorithm
== DNSSEC_ALGORITHM_ECDSAP384SHA384
) {
395 curve
= "NIST P-384";
399 if (dnskey
->dnskey
.key_size
!= key_size
* 2)
402 if (rrsig
->rrsig
.signature_size
!= key_size
* 2)
405 q
= alloca(key_size
*2 + 1);
406 q
[0] = 0x04; /* Prepend 0x04 to indicate an uncompressed key */
407 memcpy(q
+1, dnskey
->dnskey
.key
, key_size
*2);
409 return dnssec_ecdsa_verify_raw(
412 rrsig
->rrsig
.signature
, key_size
,
413 (uint8_t*) rrsig
->rrsig
.signature
+ key_size
, key_size
,
418 #if GCRYPT_VERSION_NUMBER >= 0x010600
419 static int dnssec_eddsa_verify_raw(
421 const void *signature_r
, size_t signature_r_size
,
422 const void *signature_s
, size_t signature_s_size
,
423 const void *data
, size_t data_size
,
424 const void *key
, size_t key_size
) {
426 gcry_sexp_t public_key_sexp
= NULL
, data_sexp
= NULL
, signature_sexp
= NULL
;
430 ge
= gcry_sexp_build(&signature_sexp
,
432 "(sig-val (eddsa (r %b) (s %b)))",
433 (int) signature_r_size
,
435 (int) signature_s_size
,
442 ge
= gcry_sexp_build(&data_sexp
,
444 "(data (flags eddsa) (hash-algo sha512) (value %b))",
452 ge
= gcry_sexp_build(&public_key_sexp
,
454 "(public-key (ecc (curve %s) (flags eddsa) (q %b)))",
463 ge
= gcry_pk_verify(signature_sexp
, data_sexp
, public_key_sexp
);
464 if (gpg_err_code(ge
) == GPG_ERR_BAD_SIGNATURE
)
467 log_debug("EdDSA signature check failed: %s", gpg_strerror(ge
));
473 gcry_sexp_release(public_key_sexp
);
475 gcry_sexp_release(signature_sexp
);
477 gcry_sexp_release(data_sexp
);
482 static int dnssec_eddsa_verify(
484 const void *data
, size_t data_size
,
485 DnsResourceRecord
*rrsig
,
486 DnsResourceRecord
*dnskey
) {
490 if (algorithm
== DNSSEC_ALGORITHM_ED25519
) {
496 if (dnskey
->dnskey
.key_size
!= key_size
)
499 if (rrsig
->rrsig
.signature_size
!= key_size
* 2)
502 return dnssec_eddsa_verify_raw(
504 rrsig
->rrsig
.signature
, key_size
,
505 (uint8_t*) rrsig
->rrsig
.signature
+ key_size
, key_size
,
507 dnskey
->dnskey
.key
, key_size
);
511 static void md_add_uint8(gcry_md_hd_t md
, uint8_t v
) {
512 gcry_md_write(md
, &v
, sizeof(v
));
515 static void md_add_uint16(gcry_md_hd_t md
, uint16_t v
) {
517 gcry_md_write(md
, &v
, sizeof(v
));
520 static void fwrite_uint8(FILE *fp
, uint8_t v
) {
521 fwrite(&v
, sizeof(v
), 1, fp
);
524 static void fwrite_uint16(FILE *fp
, uint16_t v
) {
526 fwrite(&v
, sizeof(v
), 1, fp
);
529 static void fwrite_uint32(FILE *fp
, uint32_t v
) {
531 fwrite(&v
, sizeof(v
), 1, fp
);
534 static int dnssec_rrsig_prepare(DnsResourceRecord
*rrsig
) {
535 int n_key_labels
, n_signer_labels
;
539 /* Checks whether the specified RRSIG RR is somewhat valid, and initializes the .n_skip_labels_source and
540 * .n_skip_labels_signer fields so that we can use them later on. */
543 assert(rrsig
->key
->type
== DNS_TYPE_RRSIG
);
545 /* Check if this RRSIG RR is already prepared */
546 if (rrsig
->n_skip_labels_source
!= (unsigned) -1)
549 if (rrsig
->rrsig
.inception
> rrsig
->rrsig
.expiration
)
552 name
= dns_resource_key_name(rrsig
->key
);
554 n_key_labels
= dns_name_count_labels(name
);
555 if (n_key_labels
< 0)
557 if (rrsig
->rrsig
.labels
> n_key_labels
)
560 n_signer_labels
= dns_name_count_labels(rrsig
->rrsig
.signer
);
561 if (n_signer_labels
< 0)
562 return n_signer_labels
;
563 if (n_signer_labels
> rrsig
->rrsig
.labels
)
566 r
= dns_name_skip(name
, n_key_labels
- n_signer_labels
, &name
);
572 /* Check if the signer is really a suffix of us */
573 r
= dns_name_equal(name
, rrsig
->rrsig
.signer
);
579 rrsig
->n_skip_labels_source
= n_key_labels
- rrsig
->rrsig
.labels
;
580 rrsig
->n_skip_labels_signer
= n_key_labels
- n_signer_labels
;
585 static int dnssec_rrsig_expired(DnsResourceRecord
*rrsig
, usec_t realtime
) {
586 usec_t expiration
, inception
, skew
;
589 assert(rrsig
->key
->type
== DNS_TYPE_RRSIG
);
591 if (realtime
== USEC_INFINITY
)
592 realtime
= now(CLOCK_REALTIME
);
594 expiration
= rrsig
->rrsig
.expiration
* USEC_PER_SEC
;
595 inception
= rrsig
->rrsig
.inception
* USEC_PER_SEC
;
597 /* Consider inverted validity intervals as expired */
598 if (inception
> expiration
)
601 /* Permit a certain amount of clock skew of 10% of the valid
602 * time range. This takes inspiration from unbound's
604 skew
= (expiration
- inception
) / 10;
608 if (inception
< skew
)
613 if (expiration
+ skew
< expiration
)
614 expiration
= USEC_INFINITY
;
618 return realtime
< inception
|| realtime
> expiration
;
621 static int algorithm_to_gcrypt_md(uint8_t algorithm
) {
623 /* Translates a DNSSEC signature algorithm into a gcrypt
626 * Note that we implement all algorithms listed as "Must
627 * implement" and "Recommended to Implement" in RFC6944. We
628 * don't implement any algorithms that are listed as
629 * "Optional" or "Must Not Implement". Specifically, we do not
630 * implement RSAMD5, DSASHA1, DH, DSA-NSEC3-SHA1, and
635 case DNSSEC_ALGORITHM_RSASHA1
:
636 case DNSSEC_ALGORITHM_RSASHA1_NSEC3_SHA1
:
639 case DNSSEC_ALGORITHM_RSASHA256
:
640 case DNSSEC_ALGORITHM_ECDSAP256SHA256
:
641 return GCRY_MD_SHA256
;
643 case DNSSEC_ALGORITHM_ECDSAP384SHA384
:
644 return GCRY_MD_SHA384
;
646 case DNSSEC_ALGORITHM_RSASHA512
:
647 return GCRY_MD_SHA512
;
654 static void dnssec_fix_rrset_ttl(
655 DnsResourceRecord
*list
[],
657 DnsResourceRecord
*rrsig
,
666 for (k
= 0; k
< n
; k
++) {
667 DnsResourceRecord
*rr
= list
[k
];
669 /* Pick the TTL as the minimum of the RR's TTL, the
670 * RR's original TTL according to the RRSIG and the
671 * RRSIG's own TTL, see RFC 4035, Section 5.3.3 */
672 rr
->ttl
= MIN3(rr
->ttl
, rrsig
->rrsig
.original_ttl
, rrsig
->ttl
);
673 rr
->expiry
= rrsig
->rrsig
.expiration
* USEC_PER_SEC
;
675 /* Copy over information about the signer and wildcard source of synthesis */
676 rr
->n_skip_labels_source
= rrsig
->n_skip_labels_source
;
677 rr
->n_skip_labels_signer
= rrsig
->n_skip_labels_signer
;
680 rrsig
->expiry
= rrsig
->rrsig
.expiration
* USEC_PER_SEC
;
683 int dnssec_verify_rrset(
685 const DnsResourceKey
*key
,
686 DnsResourceRecord
*rrsig
,
687 DnsResourceRecord
*dnskey
,
689 DnssecResult
*result
) {
691 uint8_t wire_format_name
[DNS_WIRE_FORMAT_HOSTNAME_MAX
];
692 DnsResourceRecord
**list
, *rr
;
693 const char *source
, *name
;
694 _cleanup_(gcry_md_closep
) gcry_md_hd_t md
= NULL
;
698 _cleanup_free_
char *sig_data
= NULL
;
699 _cleanup_fclose_
FILE *f
= NULL
;
708 assert(rrsig
->key
->type
== DNS_TYPE_RRSIG
);
709 assert(dnskey
->key
->type
== DNS_TYPE_DNSKEY
);
711 /* Verifies that the RRSet matches the specified "key" in "a",
712 * using the signature "rrsig" and the key "dnskey". It's
713 * assumed that RRSIG and DNSKEY match. */
715 r
= dnssec_rrsig_prepare(rrsig
);
717 *result
= DNSSEC_INVALID
;
723 r
= dnssec_rrsig_expired(rrsig
, realtime
);
727 *result
= DNSSEC_SIGNATURE_EXPIRED
;
731 name
= dns_resource_key_name(key
);
733 /* Some keys may only appear signed in the zone apex, and are invalid anywhere else. (SOA, NS...) */
734 if (dns_type_apex_only(rrsig
->rrsig
.type_covered
)) {
735 r
= dns_name_equal(rrsig
->rrsig
.signer
, name
);
739 *result
= DNSSEC_INVALID
;
744 /* OTOH DS RRs may not appear in the zone apex, but are valid everywhere else. */
745 if (rrsig
->rrsig
.type_covered
== DNS_TYPE_DS
) {
746 r
= dns_name_equal(rrsig
->rrsig
.signer
, name
);
750 *result
= DNSSEC_INVALID
;
755 /* Determine the "Source of Synthesis" and whether this is a wildcard RRSIG */
756 r
= dns_name_suffix(name
, rrsig
->rrsig
.labels
, &source
);
759 if (r
> 0 && !dns_type_may_wildcard(rrsig
->rrsig
.type_covered
)) {
760 /* We refuse to validate NSEC3 or SOA RRs that are synthesized from wildcards */
761 *result
= DNSSEC_INVALID
;
765 /* If we stripped a single label, then let's see if that maybe was "*". If so, we are not really
766 * synthesized from a wildcard, we are the wildcard itself. Treat that like a normal name. */
767 r
= dns_name_startswith(name
, "*");
777 /* Collect all relevant RRs in a single array, so that we can look at the RRset */
778 list
= newa(DnsResourceRecord
*, dns_answer_size(a
));
780 DNS_ANSWER_FOREACH(rr
, a
) {
781 r
= dns_resource_key_equal(key
, rr
->key
);
787 /* We need the wire format for ordering, and digest calculation */
788 r
= dns_resource_record_to_wire_format(rr
, true);
794 if (n
> VERIFY_RRS_MAX
)
801 /* Bring the RRs into canonical order */
802 typesafe_qsort(list
, n
, rr_compare
);
804 f
= open_memstream(&sig_data
, &sig_size
);
807 __fsetlocking(f
, FSETLOCKING_BYCALLER
);
809 fwrite_uint16(f
, rrsig
->rrsig
.type_covered
);
810 fwrite_uint8(f
, rrsig
->rrsig
.algorithm
);
811 fwrite_uint8(f
, rrsig
->rrsig
.labels
);
812 fwrite_uint32(f
, rrsig
->rrsig
.original_ttl
);
813 fwrite_uint32(f
, rrsig
->rrsig
.expiration
);
814 fwrite_uint32(f
, rrsig
->rrsig
.inception
);
815 fwrite_uint16(f
, rrsig
->rrsig
.key_tag
);
817 r
= dns_name_to_wire_format(rrsig
->rrsig
.signer
, wire_format_name
, sizeof(wire_format_name
), true);
820 fwrite(wire_format_name
, 1, r
, f
);
822 /* Convert the source of synthesis into wire format */
823 r
= dns_name_to_wire_format(source
, wire_format_name
, sizeof(wire_format_name
), true);
827 for (k
= 0; k
< n
; k
++) {
832 /* Hash the source of synthesis. If this is a wildcard, then prefix it with the *. label */
834 fwrite((uint8_t[]) { 1, '*'}, sizeof(uint8_t), 2, f
);
835 fwrite(wire_format_name
, 1, r
, f
);
837 fwrite_uint16(f
, rr
->key
->type
);
838 fwrite_uint16(f
, rr
->key
->class);
839 fwrite_uint32(f
, rrsig
->rrsig
.original_ttl
);
841 l
= DNS_RESOURCE_RECORD_RDATA_SIZE(rr
);
844 fwrite_uint16(f
, (uint16_t) l
);
845 fwrite(DNS_RESOURCE_RECORD_RDATA(rr
), 1, l
, f
);
848 r
= fflush_and_check(f
);
852 initialize_libgcrypt(false);
854 switch (rrsig
->rrsig
.algorithm
) {
855 #if GCRYPT_VERSION_NUMBER >= 0x010600
856 case DNSSEC_ALGORITHM_ED25519
:
859 case DNSSEC_ALGORITHM_ED25519
:
861 case DNSSEC_ALGORITHM_ED448
:
862 *result
= DNSSEC_UNSUPPORTED_ALGORITHM
;
865 /* OK, the RRs are now in canonical order. Let's calculate the digest */
866 md_algorithm
= algorithm_to_gcrypt_md(rrsig
->rrsig
.algorithm
);
867 if (md_algorithm
== -EOPNOTSUPP
) {
868 *result
= DNSSEC_UNSUPPORTED_ALGORITHM
;
871 if (md_algorithm
< 0)
874 gcry_md_open(&md
, md_algorithm
, 0);
878 hash_size
= gcry_md_get_algo_dlen(md_algorithm
);
879 assert(hash_size
> 0);
881 gcry_md_write(md
, sig_data
, sig_size
);
883 hash
= gcry_md_read(md
, 0);
888 switch (rrsig
->rrsig
.algorithm
) {
890 case DNSSEC_ALGORITHM_RSASHA1
:
891 case DNSSEC_ALGORITHM_RSASHA1_NSEC3_SHA1
:
892 case DNSSEC_ALGORITHM_RSASHA256
:
893 case DNSSEC_ALGORITHM_RSASHA512
:
894 r
= dnssec_rsa_verify(
895 gcry_md_algo_name(md_algorithm
),
901 case DNSSEC_ALGORITHM_ECDSAP256SHA256
:
902 case DNSSEC_ALGORITHM_ECDSAP384SHA384
:
903 r
= dnssec_ecdsa_verify(
904 gcry_md_algo_name(md_algorithm
),
905 rrsig
->rrsig
.algorithm
,
910 #if GCRYPT_VERSION_NUMBER >= 0x010600
911 case DNSSEC_ALGORITHM_ED25519
:
912 r
= dnssec_eddsa_verify(
913 rrsig
->rrsig
.algorithm
,
923 /* Now, fix the ttl, expiry, and remember the synthesizing source and the signer */
925 dnssec_fix_rrset_ttl(list
, n
, rrsig
, realtime
);
928 *result
= DNSSEC_INVALID
;
930 *result
= DNSSEC_VALIDATED_WILDCARD
;
932 *result
= DNSSEC_VALIDATED
;
937 int dnssec_rrsig_match_dnskey(DnsResourceRecord
*rrsig
, DnsResourceRecord
*dnskey
, bool revoked_ok
) {
942 /* Checks if the specified DNSKEY RR matches the key used for
943 * the signature in the specified RRSIG RR */
945 if (rrsig
->key
->type
!= DNS_TYPE_RRSIG
)
948 if (dnskey
->key
->type
!= DNS_TYPE_DNSKEY
)
950 if (dnskey
->key
->class != rrsig
->key
->class)
952 if ((dnskey
->dnskey
.flags
& DNSKEY_FLAG_ZONE_KEY
) == 0)
954 if (!revoked_ok
&& (dnskey
->dnskey
.flags
& DNSKEY_FLAG_REVOKE
))
956 if (dnskey
->dnskey
.protocol
!= 3)
958 if (dnskey
->dnskey
.algorithm
!= rrsig
->rrsig
.algorithm
)
961 if (dnssec_keytag(dnskey
, false) != rrsig
->rrsig
.key_tag
)
964 return dns_name_equal(dns_resource_key_name(dnskey
->key
), rrsig
->rrsig
.signer
);
967 int dnssec_key_match_rrsig(const DnsResourceKey
*key
, DnsResourceRecord
*rrsig
) {
971 /* Checks if the specified RRSIG RR protects the RRSet of the specified RR key. */
973 if (rrsig
->key
->type
!= DNS_TYPE_RRSIG
)
975 if (rrsig
->key
->class != key
->class)
977 if (rrsig
->rrsig
.type_covered
!= key
->type
)
980 return dns_name_equal(dns_resource_key_name(rrsig
->key
), dns_resource_key_name(key
));
983 int dnssec_verify_rrset_search(
985 const DnsResourceKey
*key
,
986 DnsAnswer
*validated_dnskeys
,
988 DnssecResult
*result
,
989 DnsResourceRecord
**ret_rrsig
) {
991 bool found_rrsig
= false, found_invalid
= false, found_expired_rrsig
= false, found_unsupported_algorithm
= false;
992 DnsResourceRecord
*rrsig
;
998 /* Verifies all RRs from "a" that match the key "key" against DNSKEYs in "validated_dnskeys" */
1000 if (!a
|| a
->n_rrs
<= 0)
1003 /* Iterate through each RRSIG RR. */
1004 DNS_ANSWER_FOREACH(rrsig
, a
) {
1005 DnsResourceRecord
*dnskey
;
1006 DnsAnswerFlags flags
;
1008 /* Is this an RRSIG RR that applies to RRs matching our key? */
1009 r
= dnssec_key_match_rrsig(key
, rrsig
);
1017 /* Look for a matching key */
1018 DNS_ANSWER_FOREACH_FLAGS(dnskey
, flags
, validated_dnskeys
) {
1019 DnssecResult one_result
;
1021 if ((flags
& DNS_ANSWER_AUTHENTICATED
) == 0)
1024 /* Is this a DNSKEY RR that matches they key of our RRSIG? */
1025 r
= dnssec_rrsig_match_dnskey(rrsig
, dnskey
, false);
1031 /* Take the time here, if it isn't set yet, so
1032 * that we do all validations with the same
1034 if (realtime
== USEC_INFINITY
)
1035 realtime
= now(CLOCK_REALTIME
);
1037 /* Yay, we found a matching RRSIG with a matching
1038 * DNSKEY, awesome. Now let's verify all entries of
1039 * the RRSet against the RRSIG and DNSKEY
1042 r
= dnssec_verify_rrset(a
, key
, rrsig
, dnskey
, realtime
, &one_result
);
1046 switch (one_result
) {
1048 case DNSSEC_VALIDATED
:
1049 case DNSSEC_VALIDATED_WILDCARD
:
1050 /* Yay, the RR has been validated,
1051 * return immediately, but fix up the expiry */
1055 *result
= one_result
;
1058 case DNSSEC_INVALID
:
1059 /* If the signature is invalid, let's try another
1060 key and/or signature. After all they
1061 key_tags and stuff are not unique, and
1062 might be shared by multiple keys. */
1063 found_invalid
= true;
1066 case DNSSEC_UNSUPPORTED_ALGORITHM
:
1067 /* If the key algorithm is
1068 unsupported, try another
1069 RRSIG/DNSKEY pair, but remember we
1070 encountered this, so that we can
1071 return a proper error when we
1072 encounter nothing better. */
1073 found_unsupported_algorithm
= true;
1076 case DNSSEC_SIGNATURE_EXPIRED
:
1077 /* If the signature is expired, try
1078 another one, but remember it, so
1079 that we can return this */
1080 found_expired_rrsig
= true;
1084 assert_not_reached("Unexpected DNSSEC validation result");
1089 if (found_expired_rrsig
)
1090 *result
= DNSSEC_SIGNATURE_EXPIRED
;
1091 else if (found_unsupported_algorithm
)
1092 *result
= DNSSEC_UNSUPPORTED_ALGORITHM
;
1093 else if (found_invalid
)
1094 *result
= DNSSEC_INVALID
;
1095 else if (found_rrsig
)
1096 *result
= DNSSEC_MISSING_KEY
;
1098 *result
= DNSSEC_NO_SIGNATURE
;
1106 int dnssec_has_rrsig(DnsAnswer
*a
, const DnsResourceKey
*key
) {
1107 DnsResourceRecord
*rr
;
1110 /* Checks whether there's at least one RRSIG in 'a' that proctects RRs of the specified key */
1112 DNS_ANSWER_FOREACH(rr
, a
) {
1113 r
= dnssec_key_match_rrsig(key
, rr
);
1123 static int digest_to_gcrypt_md(uint8_t algorithm
) {
1125 /* Translates a DNSSEC digest algorithm into a gcrypt digest identifier */
1127 switch (algorithm
) {
1129 case DNSSEC_DIGEST_SHA1
:
1130 return GCRY_MD_SHA1
;
1132 case DNSSEC_DIGEST_SHA256
:
1133 return GCRY_MD_SHA256
;
1135 case DNSSEC_DIGEST_SHA384
:
1136 return GCRY_MD_SHA384
;
1143 int dnssec_verify_dnskey_by_ds(DnsResourceRecord
*dnskey
, DnsResourceRecord
*ds
, bool mask_revoke
) {
1144 uint8_t wire_format
[DNS_WIRE_FORMAT_HOSTNAME_MAX
];
1145 _cleanup_(gcry_md_closep
) gcry_md_hd_t md
= NULL
;
1147 int md_algorithm
, r
;
1153 /* Implements DNSKEY verification by a DS, according to RFC 4035, section 5.2 */
1155 if (dnskey
->key
->type
!= DNS_TYPE_DNSKEY
)
1157 if (ds
->key
->type
!= DNS_TYPE_DS
)
1159 if ((dnskey
->dnskey
.flags
& DNSKEY_FLAG_ZONE_KEY
) == 0)
1160 return -EKEYREJECTED
;
1161 if (!mask_revoke
&& (dnskey
->dnskey
.flags
& DNSKEY_FLAG_REVOKE
))
1162 return -EKEYREJECTED
;
1163 if (dnskey
->dnskey
.protocol
!= 3)
1164 return -EKEYREJECTED
;
1166 if (dnskey
->dnskey
.algorithm
!= ds
->ds
.algorithm
)
1168 if (dnssec_keytag(dnskey
, mask_revoke
) != ds
->ds
.key_tag
)
1171 initialize_libgcrypt(false);
1173 md_algorithm
= digest_to_gcrypt_md(ds
->ds
.digest_type
);
1174 if (md_algorithm
< 0)
1175 return md_algorithm
;
1177 hash_size
= gcry_md_get_algo_dlen(md_algorithm
);
1178 assert(hash_size
> 0);
1180 if (ds
->ds
.digest_size
!= hash_size
)
1183 r
= dns_name_to_wire_format(dns_resource_key_name(dnskey
->key
), wire_format
, sizeof(wire_format
), true);
1187 gcry_md_open(&md
, md_algorithm
, 0);
1191 gcry_md_write(md
, wire_format
, r
);
1193 md_add_uint16(md
, dnskey
->dnskey
.flags
& ~DNSKEY_FLAG_REVOKE
);
1195 md_add_uint16(md
, dnskey
->dnskey
.flags
);
1196 md_add_uint8(md
, dnskey
->dnskey
.protocol
);
1197 md_add_uint8(md
, dnskey
->dnskey
.algorithm
);
1198 gcry_md_write(md
, dnskey
->dnskey
.key
, dnskey
->dnskey
.key_size
);
1200 result
= gcry_md_read(md
, 0);
1204 return memcmp(result
, ds
->ds
.digest
, ds
->ds
.digest_size
) == 0;
1207 int dnssec_verify_dnskey_by_ds_search(DnsResourceRecord
*dnskey
, DnsAnswer
*validated_ds
) {
1208 DnsResourceRecord
*ds
;
1209 DnsAnswerFlags flags
;
1214 if (dnskey
->key
->type
!= DNS_TYPE_DNSKEY
)
1217 DNS_ANSWER_FOREACH_FLAGS(ds
, flags
, validated_ds
) {
1219 if ((flags
& DNS_ANSWER_AUTHENTICATED
) == 0)
1222 if (ds
->key
->type
!= DNS_TYPE_DS
)
1224 if (ds
->key
->class != dnskey
->key
->class)
1227 r
= dns_name_equal(dns_resource_key_name(dnskey
->key
), dns_resource_key_name(ds
->key
));
1233 r
= dnssec_verify_dnskey_by_ds(dnskey
, ds
, false);
1234 if (IN_SET(r
, -EKEYREJECTED
, -EOPNOTSUPP
))
1235 return 0; /* The DNSKEY is revoked or otherwise invalid, or we don't support the digest algorithm */
1245 static int nsec3_hash_to_gcrypt_md(uint8_t algorithm
) {
1247 /* Translates a DNSSEC NSEC3 hash algorithm into a gcrypt digest identifier */
1249 switch (algorithm
) {
1251 case NSEC3_ALGORITHM_SHA1
:
1252 return GCRY_MD_SHA1
;
1259 int dnssec_nsec3_hash(DnsResourceRecord
*nsec3
, const char *name
, void *ret
) {
1260 uint8_t wire_format
[DNS_WIRE_FORMAT_HOSTNAME_MAX
];
1261 gcry_md_hd_t md
= NULL
;
1272 if (nsec3
->key
->type
!= DNS_TYPE_NSEC3
)
1275 if (nsec3
->nsec3
.iterations
> NSEC3_ITERATIONS_MAX
) {
1276 log_debug("Ignoring NSEC3 RR %s with excessive number of iterations.", dns_resource_record_to_string(nsec3
));
1280 algorithm
= nsec3_hash_to_gcrypt_md(nsec3
->nsec3
.algorithm
);
1284 initialize_libgcrypt(false);
1286 hash_size
= gcry_md_get_algo_dlen(algorithm
);
1287 assert(hash_size
> 0);
1289 if (nsec3
->nsec3
.next_hashed_name_size
!= hash_size
)
1292 r
= dns_name_to_wire_format(name
, wire_format
, sizeof(wire_format
), true);
1296 gcry_md_open(&md
, algorithm
, 0);
1300 gcry_md_write(md
, wire_format
, r
);
1301 gcry_md_write(md
, nsec3
->nsec3
.salt
, nsec3
->nsec3
.salt_size
);
1303 result
= gcry_md_read(md
, 0);
1309 for (k
= 0; k
< nsec3
->nsec3
.iterations
; k
++) {
1310 uint8_t tmp
[hash_size
];
1311 memcpy(tmp
, result
, hash_size
);
1314 gcry_md_write(md
, tmp
, hash_size
);
1315 gcry_md_write(md
, nsec3
->nsec3
.salt
, nsec3
->nsec3
.salt_size
);
1317 result
= gcry_md_read(md
, 0);
1324 memcpy(ret
, result
, hash_size
);
1325 r
= (int) hash_size
;
1332 static int nsec3_is_good(DnsResourceRecord
*rr
, DnsResourceRecord
*nsec3
) {
1338 if (rr
->key
->type
!= DNS_TYPE_NSEC3
)
1341 /* RFC 5155, Section 8.2 says we MUST ignore NSEC3 RRs with flags != 0 or 1 */
1342 if (!IN_SET(rr
->nsec3
.flags
, 0, 1))
1345 /* Ignore NSEC3 RRs whose algorithm we don't know */
1346 if (nsec3_hash_to_gcrypt_md(rr
->nsec3
.algorithm
) < 0)
1348 /* Ignore NSEC3 RRs with an excessive number of required iterations */
1349 if (rr
->nsec3
.iterations
> NSEC3_ITERATIONS_MAX
)
1352 /* Ignore NSEC3 RRs generated from wildcards. If these NSEC3 RRs weren't correctly signed we can't make this
1353 * check (since rr->n_skip_labels_source is -1), but that's OK, as we won't trust them anyway in that case. */
1354 if (!IN_SET(rr
->n_skip_labels_source
, 0, (unsigned) -1))
1356 /* Ignore NSEC3 RRs that are located anywhere else than one label below the zone */
1357 if (!IN_SET(rr
->n_skip_labels_signer
, 1, (unsigned) -1))
1363 /* If a second NSEC3 RR is specified, also check if they are from the same zone. */
1365 if (nsec3
== rr
) /* Shortcut */
1368 if (rr
->key
->class != nsec3
->key
->class)
1370 if (rr
->nsec3
.algorithm
!= nsec3
->nsec3
.algorithm
)
1372 if (rr
->nsec3
.iterations
!= nsec3
->nsec3
.iterations
)
1374 if (rr
->nsec3
.salt_size
!= nsec3
->nsec3
.salt_size
)
1376 if (memcmp_safe(rr
->nsec3
.salt
, nsec3
->nsec3
.salt
, rr
->nsec3
.salt_size
) != 0)
1379 a
= dns_resource_key_name(rr
->key
);
1380 r
= dns_name_parent(&a
); /* strip off hash */
1384 b
= dns_resource_key_name(nsec3
->key
);
1385 r
= dns_name_parent(&b
); /* strip off hash */
1389 /* Make sure both have the same parent */
1390 return dns_name_equal(a
, b
);
1393 static int nsec3_hashed_domain_format(const uint8_t *hashed
, size_t hashed_size
, const char *zone
, char **ret
) {
1394 _cleanup_free_
char *l
= NULL
;
1398 assert(hashed_size
> 0);
1402 l
= base32hexmem(hashed
, hashed_size
, false);
1406 j
= strjoin(l
, ".", zone
);
1411 return (int) hashed_size
;
1414 static int nsec3_hashed_domain_make(DnsResourceRecord
*nsec3
, const char *domain
, const char *zone
, char **ret
) {
1415 uint8_t hashed
[DNSSEC_HASH_SIZE_MAX
];
1423 hashed_size
= dnssec_nsec3_hash(nsec3
, domain
, hashed
);
1424 if (hashed_size
< 0)
1427 return nsec3_hashed_domain_format(hashed
, (size_t) hashed_size
, zone
, ret
);
1430 /* See RFC 5155, Section 8
1431 * First try to find a NSEC3 record that matches our query precisely, if that fails, find the closest
1432 * enclosure. Secondly, find a proof that there is no closer enclosure and either a proof that there
1433 * is no wildcard domain as a direct descendant of the closest enclosure, or find an NSEC3 record that
1434 * matches the wildcard domain.
1436 * Based on this we can prove either the existence of the record in @key, or NXDOMAIN or NODATA, or
1437 * that there is no proof either way. The latter is the case if a the proof of non-existence of a given
1438 * name uses an NSEC3 record with the opt-out bit set. Lastly, if we are given insufficient NSEC3 records
1439 * to conclude anything we indicate this by returning NO_RR. */
1440 static int dnssec_test_nsec3(DnsAnswer
*answer
, DnsResourceKey
*key
, DnssecNsecResult
*result
, bool *authenticated
, uint32_t *ttl
) {
1441 _cleanup_free_
char *next_closer_domain
= NULL
, *wildcard_domain
= NULL
;
1442 const char *zone
, *p
, *pp
= NULL
, *wildcard
;
1443 DnsResourceRecord
*rr
, *enclosure_rr
, *zone_rr
, *wildcard_rr
= NULL
;
1444 DnsAnswerFlags flags
;
1446 bool a
, no_closer
= false, no_wildcard
= false, optout
= false;
1451 /* First step, find the zone name and the NSEC3 parameters of the zone.
1452 * it is sufficient to look for the longest common suffix we find with
1453 * any NSEC3 RR in the response. Any NSEC3 record will do as all NSEC3
1454 * records from a given zone in a response must use the same
1456 zone
= dns_resource_key_name(key
);
1458 DNS_ANSWER_FOREACH_FLAGS(zone_rr
, flags
, answer
) {
1459 r
= nsec3_is_good(zone_rr
, NULL
);
1465 r
= dns_name_equal_skip(dns_resource_key_name(zone_rr
->key
), 1, zone
);
1472 /* Strip one label from the front */
1473 r
= dns_name_parent(&zone
);
1480 *result
= DNSSEC_NSEC_NO_RR
;
1484 /* Second step, find the closest encloser NSEC3 RR in 'answer' that matches 'key' */
1485 p
= dns_resource_key_name(key
);
1487 _cleanup_free_
char *hashed_domain
= NULL
;
1489 hashed_size
= nsec3_hashed_domain_make(zone_rr
, p
, zone
, &hashed_domain
);
1490 if (hashed_size
== -EOPNOTSUPP
) {
1491 *result
= DNSSEC_NSEC_UNSUPPORTED_ALGORITHM
;
1494 if (hashed_size
< 0)
1497 DNS_ANSWER_FOREACH_FLAGS(enclosure_rr
, flags
, answer
) {
1499 r
= nsec3_is_good(enclosure_rr
, zone_rr
);
1505 if (enclosure_rr
->nsec3
.next_hashed_name_size
!= (size_t) hashed_size
)
1508 r
= dns_name_equal(dns_resource_key_name(enclosure_rr
->key
), hashed_domain
);
1512 a
= flags
& DNS_ANSWER_AUTHENTICATED
;
1513 goto found_closest_encloser
;
1517 /* We didn't find the closest encloser with this name,
1518 * but let's remember this domain name, it might be
1519 * the next closer name */
1523 /* Strip one label from the front */
1524 r
= dns_name_parent(&p
);
1531 *result
= DNSSEC_NSEC_NO_RR
;
1534 found_closest_encloser
:
1535 /* We found a closest encloser in 'p'; next closer is 'pp' */
1538 /* We have an exact match! If we area looking for a DS RR, then we must insist that we got the NSEC3 RR
1539 * from the parent. Otherwise the one from the child. Do so, by checking whether SOA and NS are
1540 * appropriately set. */
1542 if (key
->type
== DNS_TYPE_DS
) {
1543 if (bitmap_isset(enclosure_rr
->nsec3
.types
, DNS_TYPE_SOA
))
1546 if (bitmap_isset(enclosure_rr
->nsec3
.types
, DNS_TYPE_NS
) &&
1547 !bitmap_isset(enclosure_rr
->nsec3
.types
, DNS_TYPE_SOA
))
1551 /* No next closer NSEC3 RR. That means there's a direct NSEC3 RR for our key. */
1552 if (bitmap_isset(enclosure_rr
->nsec3
.types
, key
->type
))
1553 *result
= DNSSEC_NSEC_FOUND
;
1554 else if (bitmap_isset(enclosure_rr
->nsec3
.types
, DNS_TYPE_CNAME
))
1555 *result
= DNSSEC_NSEC_CNAME
;
1557 *result
= DNSSEC_NSEC_NODATA
;
1562 *ttl
= enclosure_rr
->ttl
;
1567 /* Ensure this is not a DNAME domain, see RFC5155, section 8.3. */
1568 if (bitmap_isset(enclosure_rr
->nsec3
.types
, DNS_TYPE_DNAME
))
1571 /* Ensure that this data is from the delegated domain
1572 * (i.e. originates from the "lower" DNS server), and isn't
1573 * just glue records (i.e. doesn't originate from the "upper"
1575 if (bitmap_isset(enclosure_rr
->nsec3
.types
, DNS_TYPE_NS
) &&
1576 !bitmap_isset(enclosure_rr
->nsec3
.types
, DNS_TYPE_SOA
))
1579 /* Prove that there is no next closer and whether or not there is a wildcard domain. */
1581 wildcard
= strjoina("*.", p
);
1582 r
= nsec3_hashed_domain_make(enclosure_rr
, wildcard
, zone
, &wildcard_domain
);
1585 if (r
!= hashed_size
)
1588 r
= nsec3_hashed_domain_make(enclosure_rr
, pp
, zone
, &next_closer_domain
);
1591 if (r
!= hashed_size
)
1594 DNS_ANSWER_FOREACH_FLAGS(rr
, flags
, answer
) {
1595 _cleanup_free_
char *next_hashed_domain
= NULL
;
1597 r
= nsec3_is_good(rr
, zone_rr
);
1603 r
= nsec3_hashed_domain_format(rr
->nsec3
.next_hashed_name
, rr
->nsec3
.next_hashed_name_size
, zone
, &next_hashed_domain
);
1607 r
= dns_name_between(dns_resource_key_name(rr
->key
), next_closer_domain
, next_hashed_domain
);
1611 if (rr
->nsec3
.flags
& 1)
1614 a
= a
&& (flags
& DNS_ANSWER_AUTHENTICATED
);
1619 r
= dns_name_equal(dns_resource_key_name(rr
->key
), wildcard_domain
);
1623 a
= a
&& (flags
& DNS_ANSWER_AUTHENTICATED
);
1628 r
= dns_name_between(dns_resource_key_name(rr
->key
), wildcard_domain
, next_hashed_domain
);
1632 if (rr
->nsec3
.flags
& 1)
1633 /* This only makes sense if we have a wildcard delegation, which is
1634 * very unlikely, see RFC 4592, Section 4.2, but we cannot rely on
1635 * this not happening, so hence cannot simply conclude NXDOMAIN as
1639 a
= a
&& (flags
& DNS_ANSWER_AUTHENTICATED
);
1645 if (wildcard_rr
&& no_wildcard
)
1649 *result
= DNSSEC_NSEC_NO_RR
;
1654 /* A wildcard exists that matches our query. */
1656 /* This is not specified in any RFC to the best of my knowledge, but
1657 * if the next closer enclosure is covered by an opt-out NSEC3 RR
1658 * it means that we cannot prove that the source of synthesis is
1659 * correct, as there may be a closer match. */
1660 *result
= DNSSEC_NSEC_OPTOUT
;
1661 else if (bitmap_isset(wildcard_rr
->nsec3
.types
, key
->type
))
1662 *result
= DNSSEC_NSEC_FOUND
;
1663 else if (bitmap_isset(wildcard_rr
->nsec3
.types
, DNS_TYPE_CNAME
))
1664 *result
= DNSSEC_NSEC_CNAME
;
1666 *result
= DNSSEC_NSEC_NODATA
;
1669 /* The RFC only specifies that we have to care for optout for NODATA for
1670 * DS records. However, children of an insecure opt-out delegation should
1671 * also be considered opt-out, rather than verified NXDOMAIN.
1672 * Note that we do not require a proof of wildcard non-existence if the
1673 * next closer domain is covered by an opt-out, as that would not provide
1674 * any additional information. */
1675 *result
= DNSSEC_NSEC_OPTOUT
;
1676 else if (no_wildcard
)
1677 *result
= DNSSEC_NSEC_NXDOMAIN
;
1679 *result
= DNSSEC_NSEC_NO_RR
;
1689 *ttl
= enclosure_rr
->ttl
;
1694 static int dnssec_nsec_wildcard_equal(DnsResourceRecord
*rr
, const char *name
) {
1695 char label
[DNS_LABEL_MAX
];
1700 assert(rr
->key
->type
== DNS_TYPE_NSEC
);
1702 /* Checks whether the specified RR has a name beginning in "*.", and if the rest is a suffix of our name */
1704 if (rr
->n_skip_labels_source
!= 1)
1707 n
= dns_resource_key_name(rr
->key
);
1708 r
= dns_label_unescape(&n
, label
, sizeof(label
));
1711 if (r
!= 1 || label
[0] != '*')
1714 return dns_name_endswith(name
, n
);
1717 static int dnssec_nsec_in_path(DnsResourceRecord
*rr
, const char *name
) {
1718 const char *nn
, *common_suffix
;
1722 assert(rr
->key
->type
== DNS_TYPE_NSEC
);
1724 /* Checks whether the specified nsec RR indicates that name is an empty non-terminal (ENT)
1726 * A couple of examples:
1728 * NSEC bar → waldo.foo.bar: indicates that foo.bar exists and is an ENT
1729 * NSEC waldo.foo.bar → yyy.zzz.xoo.bar: indicates that xoo.bar and zzz.xoo.bar exist and are ENTs
1730 * NSEC yyy.zzz.xoo.bar → bar: indicates pretty much nothing about ENTs
1733 /* First, determine parent of next domain. */
1734 nn
= rr
->nsec
.next_domain_name
;
1735 r
= dns_name_parent(&nn
);
1739 /* If the name we just determined is not equal or child of the name we are interested in, then we can't say
1740 * anything at all. */
1741 r
= dns_name_endswith(nn
, name
);
1745 /* 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. */
1746 r
= dns_name_common_suffix(dns_resource_key_name(rr
->key
), rr
->nsec
.next_domain_name
, &common_suffix
);
1750 return dns_name_endswith(name
, common_suffix
);
1753 static int dnssec_nsec_from_parent_zone(DnsResourceRecord
*rr
, const char *name
) {
1757 assert(rr
->key
->type
== DNS_TYPE_NSEC
);
1759 /* Checks whether this NSEC originates to the parent zone or the child zone. */
1761 r
= dns_name_parent(&name
);
1765 r
= dns_name_equal(name
, dns_resource_key_name(rr
->key
));
1769 /* DNAME, and NS without SOA is an indication for a delegation. */
1770 if (bitmap_isset(rr
->nsec
.types
, DNS_TYPE_DNAME
))
1773 if (bitmap_isset(rr
->nsec
.types
, DNS_TYPE_NS
) && !bitmap_isset(rr
->nsec
.types
, DNS_TYPE_SOA
))
1779 static int dnssec_nsec_covers(DnsResourceRecord
*rr
, const char *name
) {
1784 assert(rr
->key
->type
== DNS_TYPE_NSEC
);
1786 /* Checks whether the name is covered by this NSEC RR. This means, that the name is somewhere below the NSEC's
1787 * signer name, and between the NSEC's two names. */
1789 r
= dns_resource_record_signer(rr
, &signer
);
1793 r
= dns_name_endswith(name
, signer
); /* this NSEC isn't suitable the name is not in the signer's domain */
1797 return dns_name_between(dns_resource_key_name(rr
->key
), name
, rr
->nsec
.next_domain_name
);
1800 static int dnssec_nsec_covers_wildcard(DnsResourceRecord
*rr
, const char *name
) {
1801 _cleanup_free_
char *wc
= NULL
;
1802 const char *common_suffix
, *signer
;
1806 assert(rr
->key
->type
== DNS_TYPE_NSEC
);
1808 /* Checks whether the "Wildcard at the Closest Encloser" is within the space covered by the specified
1809 * RR. Specifically, checks whether 'name' has the common suffix of the NSEC RR's owner and next names as
1810 * suffix, and whether the NSEC covers the name generated by that suffix prepended with an asterisk label.
1812 * NSEC bar → waldo.foo.bar: indicates that *.bar and *.foo.bar do not exist
1813 * NSEC waldo.foo.bar → yyy.zzz.xoo.bar: indicates that *.xoo.bar and *.zzz.xoo.bar do not exist (and more ...)
1814 * NSEC yyy.zzz.xoo.bar → bar: indicates that a number of wildcards don#t exist either...
1817 r
= dns_resource_record_signer(rr
, &signer
);
1821 r
= dns_name_endswith(name
, signer
); /* this NSEC isn't suitable the name is not in the signer's domain */
1825 r
= dns_name_endswith(name
, dns_resource_key_name(rr
->key
));
1828 if (r
> 0) /* If the name we are interested in is a child of the NSEC RR, then append the asterisk to the NSEC
1830 r
= dns_name_concat("*", dns_resource_key_name(rr
->key
), &wc
);
1832 r
= dns_name_common_suffix(dns_resource_key_name(rr
->key
), rr
->nsec
.next_domain_name
, &common_suffix
);
1836 r
= dns_name_concat("*", common_suffix
, &wc
);
1841 return dns_name_between(dns_resource_key_name(rr
->key
), wc
, rr
->nsec
.next_domain_name
);
1844 int dnssec_nsec_test(DnsAnswer
*answer
, DnsResourceKey
*key
, DnssecNsecResult
*result
, bool *authenticated
, uint32_t *ttl
) {
1845 bool have_nsec3
= false, covering_rr_authenticated
= false, wildcard_rr_authenticated
= false;
1846 DnsResourceRecord
*rr
, *covering_rr
= NULL
, *wildcard_rr
= NULL
;
1847 DnsAnswerFlags flags
;
1854 /* Look for any NSEC/NSEC3 RRs that say something about the specified key. */
1856 name
= dns_resource_key_name(key
);
1858 DNS_ANSWER_FOREACH_FLAGS(rr
, flags
, answer
) {
1860 if (rr
->key
->class != key
->class)
1863 have_nsec3
= have_nsec3
|| (rr
->key
->type
== DNS_TYPE_NSEC3
);
1865 if (rr
->key
->type
!= DNS_TYPE_NSEC
)
1868 /* The following checks only make sense for NSEC RRs that are not expanded from a wildcard */
1869 r
= dns_resource_record_is_synthetic(rr
);
1875 /* Check if this is a direct match. If so, we have encountered a NODATA case */
1876 r
= dns_name_equal(dns_resource_key_name(rr
->key
), name
);
1880 /* If it's not a direct match, maybe it's a wild card match? */
1881 r
= dnssec_nsec_wildcard_equal(rr
, name
);
1886 if (key
->type
== DNS_TYPE_DS
) {
1887 /* If we look for a DS RR and the server sent us the NSEC RR of the child zone
1888 * we have a problem. For DS RRs we want the NSEC RR from the parent */
1889 if (bitmap_isset(rr
->nsec
.types
, DNS_TYPE_SOA
))
1892 /* For all RR types, ensure that if NS is set SOA is set too, so that we know
1893 * we got the child's NSEC. */
1894 if (bitmap_isset(rr
->nsec
.types
, DNS_TYPE_NS
) &&
1895 !bitmap_isset(rr
->nsec
.types
, DNS_TYPE_SOA
))
1899 if (bitmap_isset(rr
->nsec
.types
, key
->type
))
1900 *result
= DNSSEC_NSEC_FOUND
;
1901 else if (bitmap_isset(rr
->nsec
.types
, DNS_TYPE_CNAME
))
1902 *result
= DNSSEC_NSEC_CNAME
;
1904 *result
= DNSSEC_NSEC_NODATA
;
1907 *authenticated
= flags
& DNS_ANSWER_AUTHENTICATED
;
1914 /* Check if the name we are looking for is an empty non-terminal within the owner or next name
1915 * of the NSEC RR. */
1916 r
= dnssec_nsec_in_path(rr
, name
);
1920 *result
= DNSSEC_NSEC_NODATA
;
1923 *authenticated
= flags
& DNS_ANSWER_AUTHENTICATED
;
1930 /* The following two "covering" checks, are not useful if the NSEC is from the parent */
1931 r
= dnssec_nsec_from_parent_zone(rr
, name
);
1937 /* Check if this NSEC RR proves the absence of an explicit RR under this name */
1938 r
= dnssec_nsec_covers(rr
, name
);
1941 if (r
> 0 && (!covering_rr
|| !covering_rr_authenticated
)) {
1943 covering_rr_authenticated
= flags
& DNS_ANSWER_AUTHENTICATED
;
1946 /* Check if this NSEC RR proves the absence of a wildcard RR under this name */
1947 r
= dnssec_nsec_covers_wildcard(rr
, name
);
1950 if (r
> 0 && (!wildcard_rr
|| !wildcard_rr_authenticated
)) {
1952 wildcard_rr_authenticated
= flags
& DNS_ANSWER_AUTHENTICATED
;
1956 if (covering_rr
&& wildcard_rr
) {
1957 /* If we could prove that neither the name itself, nor the wildcard at the closest encloser exists, we
1958 * proved the NXDOMAIN case. */
1959 *result
= DNSSEC_NSEC_NXDOMAIN
;
1962 *authenticated
= covering_rr_authenticated
&& wildcard_rr_authenticated
;
1964 *ttl
= MIN(covering_rr
->ttl
, wildcard_rr
->ttl
);
1969 /* OK, this was not sufficient. Let's see if NSEC3 can help. */
1971 return dnssec_test_nsec3(answer
, key
, result
, authenticated
, ttl
);
1973 /* No approproate NSEC RR found, report this. */
1974 *result
= DNSSEC_NSEC_NO_RR
;
1978 static int dnssec_nsec_test_enclosed(DnsAnswer
*answer
, uint16_t type
, const char *name
, const char *zone
, bool *authenticated
) {
1979 DnsResourceRecord
*rr
;
1980 DnsAnswerFlags flags
;
1986 /* Checks whether there's an NSEC/NSEC3 that proves that the specified 'name' is non-existing in the specified
1987 * 'zone'. The 'zone' must be a suffix of the 'name'. */
1989 DNS_ANSWER_FOREACH_FLAGS(rr
, flags
, answer
) {
1992 if (rr
->key
->type
!= type
&& type
!= DNS_TYPE_ANY
)
1995 switch (rr
->key
->type
) {
1999 /* We only care for NSEC RRs from the indicated zone */
2000 r
= dns_resource_record_is_signer(rr
, zone
);
2006 r
= dns_name_between(dns_resource_key_name(rr
->key
), name
, rr
->nsec
.next_domain_name
);
2013 case DNS_TYPE_NSEC3
: {
2014 _cleanup_free_
char *hashed_domain
= NULL
, *next_hashed_domain
= NULL
;
2016 /* We only care for NSEC3 RRs from the indicated zone */
2017 r
= dns_resource_record_is_signer(rr
, zone
);
2023 r
= nsec3_is_good(rr
, NULL
);
2029 /* Format the domain we are testing with the NSEC3 RR's hash function */
2030 r
= nsec3_hashed_domain_make(
2037 if ((size_t) r
!= rr
->nsec3
.next_hashed_name_size
)
2040 /* Format the NSEC3's next hashed name as proper domain name */
2041 r
= nsec3_hashed_domain_format(
2042 rr
->nsec3
.next_hashed_name
,
2043 rr
->nsec3
.next_hashed_name_size
,
2045 &next_hashed_domain
);
2049 r
= dns_name_between(dns_resource_key_name(rr
->key
), hashed_domain
, next_hashed_domain
);
2063 *authenticated
= flags
& DNS_ANSWER_AUTHENTICATED
;
2071 static int dnssec_test_positive_wildcard_nsec3(
2076 bool *authenticated
) {
2078 const char *next_closer
= NULL
;
2081 /* Run a positive NSEC3 wildcard proof. Specifically:
2083 * A proof that the "next closer" of the generating wildcard does not exist.
2085 * Note a key difference between the NSEC3 and NSEC versions of the proof. NSEC RRs don't have to exist for
2086 * empty non-transients. NSEC3 RRs however have to. This means it's sufficient to check if the next closer name
2087 * exists for the NSEC3 RR and we are done.
2089 * 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
2090 * c.d.e.f does not exist. */
2094 r
= dns_name_parent(&name
);
2098 r
= dns_name_equal(name
, source
);
2105 return dnssec_nsec_test_enclosed(answer
, DNS_TYPE_NSEC3
, next_closer
, zone
, authenticated
);
2108 static int dnssec_test_positive_wildcard_nsec(
2113 bool *_authenticated
) {
2115 bool authenticated
= true;
2118 /* Run a positive NSEC wildcard proof. Specifically:
2120 * A proof that there's neither a wildcard name nor a non-wildcard name that is a suffix of the name "name" and
2121 * a prefix of the synthesizing source "source" in the zone "zone".
2123 * See RFC 5155, Section 8.8 and RFC 4035, Section 5.3.4
2125 * 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
2126 * have to prove that none of the following exist:
2136 _cleanup_free_
char *wc
= NULL
;
2139 /* Check if there's an NSEC or NSEC3 RR that proves that the mame we determined is really non-existing,
2140 * i.e between the owner name and the next name of an NSEC RR. */
2141 r
= dnssec_nsec_test_enclosed(answer
, DNS_TYPE_NSEC
, name
, zone
, &a
);
2145 authenticated
= authenticated
&& a
;
2147 /* Strip one label off */
2148 r
= dns_name_parent(&name
);
2152 /* Did we reach the source of synthesis? */
2153 r
= dns_name_equal(name
, source
);
2157 /* Successful exit */
2158 *_authenticated
= authenticated
;
2162 /* Safety check, that the source of synthesis is still our suffix */
2163 r
= dns_name_endswith(name
, source
);
2169 /* Replace the label we stripped off with an asterisk */
2170 wc
= strappend("*.", name
);
2174 /* And check if the proof holds for the asterisk name, too */
2175 r
= dnssec_nsec_test_enclosed(answer
, DNS_TYPE_NSEC
, wc
, zone
, &a
);
2179 authenticated
= authenticated
&& a
;
2180 /* In the next iteration we'll check the non-asterisk-prefixed version */
2184 int dnssec_test_positive_wildcard(
2189 bool *authenticated
) {
2196 assert(authenticated
);
2198 r
= dns_answer_contains_zone_nsec3(answer
, zone
);
2202 return dnssec_test_positive_wildcard_nsec3(answer
, name
, source
, zone
, authenticated
);
2204 return dnssec_test_positive_wildcard_nsec(answer
, name
, source
, zone
, authenticated
);
2209 int dnssec_verify_rrset(
2211 const DnsResourceKey
*key
,
2212 DnsResourceRecord
*rrsig
,
2213 DnsResourceRecord
*dnskey
,
2215 DnssecResult
*result
) {
2220 int dnssec_rrsig_match_dnskey(DnsResourceRecord
*rrsig
, DnsResourceRecord
*dnskey
, bool revoked_ok
) {
2225 int dnssec_key_match_rrsig(const DnsResourceKey
*key
, DnsResourceRecord
*rrsig
) {
2230 int dnssec_verify_rrset_search(
2232 const DnsResourceKey
*key
,
2233 DnsAnswer
*validated_dnskeys
,
2235 DnssecResult
*result
,
2236 DnsResourceRecord
**ret_rrsig
) {
2241 int dnssec_has_rrsig(DnsAnswer
*a
, const DnsResourceKey
*key
) {
2246 int dnssec_verify_dnskey_by_ds(DnsResourceRecord
*dnskey
, DnsResourceRecord
*ds
, bool mask_revoke
) {
2251 int dnssec_verify_dnskey_by_ds_search(DnsResourceRecord
*dnskey
, DnsAnswer
*validated_ds
) {
2256 int dnssec_nsec3_hash(DnsResourceRecord
*nsec3
, const char *name
, void *ret
) {
2261 int dnssec_nsec_test(DnsAnswer
*answer
, DnsResourceKey
*key
, DnssecNsecResult
*result
, bool *authenticated
, uint32_t *ttl
) {
2266 int dnssec_test_positive_wildcard(
2271 bool *authenticated
) {
2278 static const char* const dnssec_result_table
[_DNSSEC_RESULT_MAX
] = {
2279 [DNSSEC_VALIDATED
] = "validated",
2280 [DNSSEC_VALIDATED_WILDCARD
] = "validated-wildcard",
2281 [DNSSEC_INVALID
] = "invalid",
2282 [DNSSEC_SIGNATURE_EXPIRED
] = "signature-expired",
2283 [DNSSEC_UNSUPPORTED_ALGORITHM
] = "unsupported-algorithm",
2284 [DNSSEC_NO_SIGNATURE
] = "no-signature",
2285 [DNSSEC_MISSING_KEY
] = "missing-key",
2286 [DNSSEC_UNSIGNED
] = "unsigned",
2287 [DNSSEC_FAILED_AUXILIARY
] = "failed-auxiliary",
2288 [DNSSEC_NSEC_MISMATCH
] = "nsec-mismatch",
2289 [DNSSEC_INCOMPATIBLE_SERVER
] = "incompatible-server",
2291 DEFINE_STRING_TABLE_LOOKUP(dnssec_result
, DnssecResult
);
2293 static const char* const dnssec_verdict_table
[_DNSSEC_VERDICT_MAX
] = {
2294 [DNSSEC_SECURE
] = "secure",
2295 [DNSSEC_INSECURE
] = "insecure",
2296 [DNSSEC_BOGUS
] = "bogus",
2297 [DNSSEC_INDETERMINATE
] = "indeterminate",
2299 DEFINE_STRING_TABLE_LOOKUP(dnssec_verdict
, DnssecVerdict
);