]>
git.ipfire.org Git - people/ms/dnsmasq.git/blob - src/dnssec.c
db5c768bd7510163f3982a204ce649859f5fe526
1 /* dnssec.c is Copyright (c) 2012 Giovanni Bajo <rasky@develer.com>
2 and Copyright (c) 2012-2015 Simon Kelley
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; version 2 dated June, 1991, or
7 (at your option) version 3 dated 29 June, 2007.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>.
22 #include <nettle/rsa.h>
23 #include <nettle/dsa.h>
25 # include <nettle/ecdsa.h>
26 # include <nettle/ecc-curve.h>
28 #include <nettle/nettle-meta.h>
29 #include <nettle/bignum.h>
31 /* Nettle-3.0 moved to a new API for DSA. We use a name that's defined in the new API
32 to detect Nettle-3, and invoke the backwards compatibility mode. */
33 #ifdef dsa_params_init
34 #include <nettle/dsa-compat.h>
39 #define SERIAL_UNDEF -100
44 /* http://www.iana.org/assignments/ds-rr-types/ds-rr-types.xhtml */
45 static char *ds_digest_name(int digest
)
49 case 1: return "sha1";
50 case 2: return "sha256";
51 case 3: return "gosthash94";
52 case 4: return "sha384";
57 /* http://www.iana.org/assignments/dns-sec-alg-numbers/dns-sec-alg-numbers.xhtml */
58 static char *algo_digest_name(int algo
)
63 case 3: return "sha1";
64 case 5: return "sha1";
65 case 6: return "sha1";
66 case 7: return "sha1";
67 case 8: return "sha256";
68 case 10: return "sha512";
69 case 12: return "gosthash94";
70 case 13: return "sha256";
71 case 14: return "sha384";
76 /* Find pointer to correct hash function in nettle library */
77 static const struct nettle_hash
*hash_find(char *name
)
84 for (i
= 0; nettle_hashes
[i
]; i
++)
86 if (strcmp(nettle_hashes
[i
]->name
, name
) == 0)
87 return nettle_hashes
[i
];
93 /* expand ctx and digest memory allocations if necessary and init hash function */
94 static int hash_init(const struct nettle_hash
*hash
, void **ctxp
, unsigned char **digestp
)
96 static void *ctx
= NULL
;
97 static unsigned char *digest
= NULL
;
98 static unsigned int ctx_sz
= 0;
99 static unsigned int digest_sz
= 0;
103 if (ctx_sz
< hash
->context_size
)
105 if (!(new = whine_malloc(hash
->context_size
)))
110 ctx_sz
= hash
->context_size
;
113 if (digest_sz
< hash
->digest_size
)
115 if (!(new = whine_malloc(hash
->digest_size
)))
120 digest_sz
= hash
->digest_size
;
131 static int dnsmasq_rsa_verify(struct blockdata
*key_data
, unsigned int key_len
, unsigned char *sig
, size_t sig_len
,
132 unsigned char *digest
, int algo
)
137 static struct rsa_public_key
*key
= NULL
;
138 static mpz_t sig_mpz
;
142 if (!(key
= whine_malloc(sizeof(struct rsa_public_key
))))
145 nettle_rsa_public_key_init(key
);
149 if ((key_len
< 3) || !(p
= blockdata_retrieve(key_data
, key_len
, NULL
)))
153 if ((exp_len
= *p
++) == 0)
155 GETSHORT(exp_len
, p
);
159 if (exp_len
>= key_len
)
162 key
->size
= key_len
- exp_len
;
163 mpz_import(key
->e
, exp_len
, 1, 1, 0, 0, p
);
164 mpz_import(key
->n
, key
->size
, 1, 1, 0, 0, p
+ exp_len
);
166 mpz_import(sig_mpz
, sig_len
, 1, 1, 0, 0, sig
);
171 return nettle_rsa_md5_verify_digest(key
, digest
, sig_mpz
);
173 return nettle_rsa_sha1_verify_digest(key
, digest
, sig_mpz
);
175 return nettle_rsa_sha256_verify_digest(key
, digest
, sig_mpz
);
177 return nettle_rsa_sha512_verify_digest(key
, digest
, sig_mpz
);
183 static int dnsmasq_dsa_verify(struct blockdata
*key_data
, unsigned int key_len
, unsigned char *sig
, size_t sig_len
,
184 unsigned char *digest
, int algo
)
189 static struct dsa_public_key
*key
= NULL
;
190 static struct dsa_signature
*sig_struct
;
194 if (!(sig_struct
= whine_malloc(sizeof(struct dsa_signature
))) ||
195 !(key
= whine_malloc(sizeof(struct dsa_public_key
))))
198 nettle_dsa_public_key_init(key
);
199 nettle_dsa_signature_init(sig_struct
);
202 if ((sig_len
< 41) || !(p
= blockdata_retrieve(key_data
, key_len
, NULL
)))
207 if (key_len
< (213 + (t
* 24)))
210 mpz_import(key
->q
, 20, 1, 1, 0, 0, p
); p
+= 20;
211 mpz_import(key
->p
, 64 + (t
*8), 1, 1, 0, 0, p
); p
+= 64 + (t
*8);
212 mpz_import(key
->g
, 64 + (t
*8), 1, 1, 0, 0, p
); p
+= 64 + (t
*8);
213 mpz_import(key
->y
, 64 + (t
*8), 1, 1, 0, 0, p
); p
+= 64 + (t
*8);
215 mpz_import(sig_struct
->r
, 20, 1, 1, 0, 0, sig
+1);
216 mpz_import(sig_struct
->s
, 20, 1, 1, 0, 0, sig
+21);
220 return nettle_dsa_sha1_verify_digest(key
, digest
, sig_struct
);
223 #ifndef NO_NETTLE_ECC
224 static int dnsmasq_ecdsa_verify(struct blockdata
*key_data
, unsigned int key_len
,
225 unsigned char *sig
, size_t sig_len
,
226 unsigned char *digest
, size_t digest_len
, int algo
)
230 struct ecc_point
*key
;
232 static struct ecc_point
*key_256
= NULL
, *key_384
= NULL
;
234 static struct dsa_signature
*sig_struct
;
238 if (!(sig_struct
= whine_malloc(sizeof(struct dsa_signature
))))
241 nettle_dsa_signature_init(sig_struct
);
251 if (!(key_256
= whine_malloc(sizeof(struct ecc_point
))))
254 nettle_ecc_point_init(key_256
, &nettle_secp_256r1
);
264 if (!(key_384
= whine_malloc(sizeof(struct ecc_point
))))
267 nettle_ecc_point_init(key_384
, &nettle_secp_384r1
);
278 if (sig_len
!= 2*t
|| key_len
!= 2*t
||
279 !(p
= blockdata_retrieve(key_data
, key_len
, NULL
)))
282 mpz_import(x
, t
, 1, 1, 0, 0, p
);
283 mpz_import(y
, t
, 1, 1, 0, 0, p
+ t
);
285 if (!ecc_point_set(key
, x
, y
))
288 mpz_import(sig_struct
->r
, t
, 1, 1, 0, 0, sig
);
289 mpz_import(sig_struct
->s
, t
, 1, 1, 0, 0, sig
+ t
);
291 return nettle_ecdsa_verify(key
, digest_len
, digest
, sig_struct
);
295 static int verify(struct blockdata
*key_data
, unsigned int key_len
, unsigned char *sig
, size_t sig_len
,
296 unsigned char *digest
, size_t digest_len
, int algo
)
302 case 1: case 5: case 7: case 8: case 10:
303 return dnsmasq_rsa_verify(key_data
, key_len
, sig
, sig_len
, digest
, algo
);
306 return dnsmasq_dsa_verify(key_data
, key_len
, sig
, sig_len
, digest
, algo
);
308 #ifndef NO_NETTLE_ECC
310 return dnsmasq_ecdsa_verify(key_data
, key_len
, sig
, sig_len
, digest
, digest_len
, algo
);
317 /* Convert from presentation format to wire format, in place.
319 Note that using extract_name to get presentation format
320 then calling to_wire() removes compression and maps case,
321 thus generating names in canonical form.
322 Calling to_wire followed by from_wire is almost an identity,
323 except that the UC remains mapped to LC.
325 static int to_wire(char *name
)
327 unsigned char *l
, *p
, term
;
330 for (l
= (unsigned char*)name
; *l
!= 0; l
= p
)
332 for (p
= l
; *p
!= '.' && *p
!= 0; p
++)
333 if (*p
>= 'A' && *p
<= 'Z')
338 if ((len
= p
- l
) != 0)
339 memmove(l
+1, l
, len
);
348 return l
+ 1 - (unsigned char *)name
;
351 /* Note: no compression allowed in input. */
352 static void from_wire(char *name
)
357 for (l
= (unsigned char *)name
; *l
!= 0; l
+= len
+1)
360 memmove(l
, l
+1, len
);
364 if ((char *)l
!= name
)
368 /* Input in presentation format */
369 static int count_labels(char *name
)
376 for (i
= 0; *name
; name
++)
383 /* Implement RFC1982 wrapped compare for 32-bit numbers */
384 static int serial_compare_32(unsigned long s1
, unsigned long s2
)
389 if ((s1
< s2
&& (s2
- s1
) < (1UL<<31)) ||
390 (s1
> s2
&& (s1
- s2
) > (1UL<<31)))
392 if ((s1
< s2
&& (s2
- s1
) > (1UL<<31)) ||
393 (s1
> s2
&& (s1
- s2
) < (1UL<<31)))
398 /* Called at startup. If the timestamp file is configured and exists, put its mtime on
399 timestamp_time. If it doesn't exist, create it, and set the mtime to 1-1-2015.
400 return -1 -> Cannot create file.
401 0 -> not using timestamp, or timestamp exists and is in past.
402 1 -> timestamp exists and is in future.
405 static time_t timestamp_time
;
406 static int back_to_the_future
;
408 int setup_timestamp(void)
412 back_to_the_future
= 0;
414 if (!daemon
->timestamp_file
)
417 if (stat(daemon
->timestamp_file
, &statbuf
) != -1)
419 timestamp_time
= statbuf
.st_mtime
;
421 if (difftime(timestamp_time
, time(0)) <= 0)
423 /* time already OK, update timestamp, and do key checking from the start. */
424 if (utime(daemon
->timestamp_file
, NULL
) == -1)
425 my_syslog(LOG_ERR
, _("failed to update mtime on %s: %s"), daemon
->timestamp_file
, strerror(errno
));
426 back_to_the_future
= 1;
434 /* NB. for explanation of O_EXCL flag, see comment on pidfile in dnsmasq.c */
435 int fd
= open(daemon
->timestamp_file
, O_WRONLY
| O_CREAT
| O_NONBLOCK
| O_EXCL
, 0666);
438 struct utimbuf timbuf
;
442 timestamp_time
= timbuf
.actime
= timbuf
.modtime
= 1420070400; /* 1-1-2015 */
443 if (utime(daemon
->timestamp_file
, &timbuf
) == 0)
451 /* Check whether today/now is between date_start and date_end */
452 static int check_date_range(unsigned long date_start
, unsigned long date_end
)
454 unsigned long curtime
= time(0);
456 /* Checking timestamps may be temporarily disabled */
458 /* If the current time if _before_ the timestamp
459 on our persistent timestamp file, then assume the
460 time if not yet correct, and don't check the
461 key timestamps. As soon as the current time is
462 later then the timestamp, update the timestamp
463 and start checking keys */
464 if (daemon
->timestamp_file
)
466 if (back_to_the_future
== 0 && difftime(timestamp_time
, curtime
) <= 0)
468 if (utime(daemon
->timestamp_file
, NULL
) != 0)
469 my_syslog(LOG_ERR
, _("failed to update mtime on %s: %s"), daemon
->timestamp_file
, strerror(errno
));
471 back_to_the_future
= 1;
472 set_option_bool(OPT_DNSSEC_TIME
);
473 queue_event(EVENT_RELOAD
); /* purge cache */
476 if (back_to_the_future
== 0)
479 else if (option_bool(OPT_DNSSEC_TIME
))
482 /* We must explicitly check against wanted values, because of SERIAL_UNDEF */
483 return serial_compare_32(curtime
, date_start
) == SERIAL_GT
484 && serial_compare_32(curtime
, date_end
) == SERIAL_LT
;
487 static u16
*get_desc(int type
)
489 /* List of RRtypes which include domains in the data.
491 integer -> no of plain bytes
494 zero is not a valid RRtype, so the final entry is returned for
495 anything which needs no mangling.
498 static u16 rr_desc
[] =
520 0, -1 /* wildcard/catchall */
525 while (*p
!= type
&& *p
!= 0)
526 while (*p
++ != (u16
)-1);
531 /* Return bytes of canonicalised rdata, when the return value is zero, the remaining
532 data, pointed to by *p, should be used raw. */
533 static int get_rdata(struct dns_header
*header
, size_t plen
, unsigned char *end
, char *buff
, int bufflen
,
534 unsigned char **p
, u16
**desc
)
538 /* No more data needs mangling */
541 /* If there's more data than we have space for, just return what fits,
542 we'll get called again for more chunks */
543 if (end
- *p
> bufflen
)
545 memcpy(buff
, *p
, bufflen
);
555 if (d
== 0 && extract_name(header
, plen
, p
, buff
, 1, 0))
556 /* domain-name, canonicalise */
557 return to_wire(buff
);
560 /* plain data preceding a domain-name, don't run off the end of the data */
574 static int expand_workspace(unsigned char ***wkspc
, int *sz
, int new)
587 if (!(p
= whine_malloc((new_sz
) * sizeof(unsigned char **))))
592 memcpy(p
, *wkspc
, *sz
* sizeof(unsigned char **));
602 /* Bubble sort the RRset into the canonical order.
603 Note that the byte-streams from two RRs may get unsynced: consider
604 RRs which have two domain-names at the start and then other data.
605 The domain-names may have different lengths in each RR, but sort equal
613 leaving the following bytes as deciding the order. Hence the nasty left1 and left2 variables.
616 static void sort_rrset(struct dns_header
*header
, size_t plen
, u16
*rr_desc
, int rrsetidx
,
617 unsigned char **rrset
, char *buff1
, char *buff2
)
623 for (swap
= 0, i
= 0; i
< rrsetidx
-1; i
++)
625 int rdlen1
, rdlen2
, left1
, left2
, len1
, len2
, len
, rc
;
627 unsigned char *end1
, *end2
;
628 /* Note that these have been determined to be OK previously,
629 so we don't need to check for NULL return here. */
630 unsigned char *p1
= skip_name(rrset
[i
], header
, plen
, 10);
631 unsigned char *p2
= skip_name(rrset
[i
+1], header
, plen
, 10);
633 p1
+= 8; /* skip class, type, ttl */
634 GETSHORT(rdlen1
, p1
);
637 p2
+= 8; /* skip class, type, ttl */
638 GETSHORT(rdlen2
, p2
);
643 for (quit
= 0, left1
= 0, left2
= 0, len1
= 0, len2
= 0; !quit
;)
646 memmove(buff1
, buff1
+ len1
- left1
, left1
);
648 if ((len1
= get_rdata(header
, plen
, end1
, buff1
+ left1
, MAXDNAME
- left1
, &p1
, &dp1
)) == 0)
652 memcpy(buff1
+ left1
, p1
, len1
);
657 memmove(buff2
, buff2
+ len2
- left2
, left2
);
659 if ((len2
= get_rdata(header
, plen
, end2
, buff2
+ left2
, MAXDNAME
- left2
, &p2
, &dp2
)) == 0)
663 memcpy(buff2
+ left2
, p2
, len2
);
668 left1
= len1
- len2
, left2
= 0, len
= len2
;
670 left2
= len2
- len1
, left1
= 0, len
= len1
;
672 rc
= (len
== 0) ? 0 : memcmp(buff1
, buff2
, len
);
674 if (rc
> 0 || (rc
== 0 && quit
&& len1
> len2
))
676 unsigned char *tmp
= rrset
[i
+1];
677 rrset
[i
+1] = rrset
[i
];
688 /* Validate a single RRset (class, type, name) in the supplied DNS reply
690 STAT_SECURE if it validates.
691 STAT_SECURE_WILDCARD if it validates and is the result of wildcard expansion.
692 (In this case *wildcard_out points to the "body" of the wildcard within name.)
693 STAT_NO_SIG no RRsigs found.
694 STAT_INSECURE RRset empty.
695 STAT_BOGUS signature is wrong, bad packet.
696 STAT_NEED_KEY need DNSKEY to complete validation (name is returned in keyname)
698 if key is non-NULL, use that key, which has the algo and tag given in the params of those names,
699 otherwise find the key in the cache.
701 name is unchanged on exit. keyname is used as workspace and trashed.
703 static int validate_rrset(time_t now
, struct dns_header
*header
, size_t plen
, int class, int type
,
704 char *name
, char *keyname
, char **wildcard_out
, struct blockdata
*key
, int keylen
, int algo_in
, int keytag_in
)
706 static unsigned char **rrset
= NULL
, **sigs
= NULL
;
707 static int rrset_sz
= 0, sig_sz
= 0;
710 int rrsetidx
, sigidx
, res
, rdlen
, j
, name_labels
;
711 struct crec
*crecp
= NULL
;
712 int type_covered
, algo
, labels
, orig_ttl
, sig_expiration
, sig_inception
, key_tag
;
713 u16
*rr_desc
= get_desc(type
);
716 *wildcard_out
= NULL
;
718 if (!(p
= skip_questions(header
, plen
)))
721 name_labels
= count_labels(name
); /* For 4035 5.3.2 check */
723 /* look for RRSIGs for this RRset and get pointers to each RR in the set. */
724 for (rrsetidx
= 0, sigidx
= 0, j
= ntohs(header
->ancount
) + ntohs(header
->nscount
);
727 unsigned char *pstart
, *pdata
;
732 if (!(res
= extract_name(header
, plen
, &p
, name
, 0, 10)))
733 return STAT_BOGUS
; /* bad packet */
743 if (!CHECK_LEN(header
, p
, plen
, rdlen
))
746 if (res
== 1 && sclass
== class)
750 if (!expand_workspace(&rrset
, &rrset_sz
, rrsetidx
))
753 rrset
[rrsetidx
++] = pstart
;
756 if (stype
== T_RRSIG
)
759 return STAT_BOGUS
; /* bad packet */
761 GETSHORT(type_covered
, p
);
763 if (type_covered
== type
)
765 if (!expand_workspace(&sigs
, &sig_sz
, sigidx
))
768 sigs
[sigidx
++] = pdata
;
771 p
= pdata
+ 2; /* restore for ADD_RDLEN */
775 if (!ADD_RDLEN(header
, p
, plen
, rdlen
))
781 return STAT_INSECURE
;
787 /* Sort RRset records into canonical order.
788 Note that at this point keyname and daemon->workspacename buffs are
789 unused, and used as workspace by the sort. */
790 sort_rrset(header
, plen
, rr_desc
, rrsetidx
, rrset
, daemon
->workspacename
, keyname
);
792 /* Now try all the sigs to try and find one which validates */
793 for (j
= 0; j
<sigidx
; j
++)
795 unsigned char *psav
, *sig
, *digest
;
796 int i
, wire_len
, sig_len
;
797 const struct nettle_hash
*hash
;
803 GETSHORT(rdlen
, p
); /* rdlen >= 18 checked previously */
806 p
+= 2; /* type_covered - already checked */
809 GETLONG(orig_ttl
, p
);
810 GETLONG(sig_expiration
, p
);
811 GETLONG(sig_inception
, p
);
812 GETSHORT(key_tag
, p
);
814 if (!extract_name(header
, plen
, &p
, keyname
, 1, 0))
817 /* RFC 4035 5.3.1 says that the Signer's Name field MUST equal
818 the name of the zone containing the RRset. We can't tell that
819 for certain, but we can check that the RRset name is equal to
820 or encloses the signers name, which should be enough to stop
821 an attacker using signatures made with the key of an unrelated
822 zone he controls. Note that the root key is always allowed. */
827 for (name_start
= name
; !hostname_isequal(name_start
, keyname
); )
828 if ((name_start
= strchr(name_start
, '.')))
829 name_start
++; /* chop a label off and try again */
836 /* Bad sig, try another */
841 /* Other 5.3.1 checks */
842 if (!check_date_range(sig_inception
, sig_expiration
) ||
843 labels
> name_labels
||
844 !(hash
= hash_find(algo_digest_name(algo
))) ||
845 !hash_init(hash
, &ctx
, &digest
))
848 /* OK, we have the signature record, see if the relevant DNSKEY is in the cache. */
849 if (!key
&& !(crecp
= cache_find_by_name(NULL
, keyname
, now
, F_DNSKEY
)))
850 return STAT_NEED_KEY
;
853 sig_len
= rdlen
- (p
- psav
);
855 nsigttl
= htonl(orig_ttl
);
857 hash
->update(ctx
, 18, psav
);
858 wire_len
= to_wire(keyname
);
859 hash
->update(ctx
, (unsigned int)wire_len
, (unsigned char*)keyname
);
862 for (i
= 0; i
< rrsetidx
; ++i
)
865 unsigned char *end
, *cp
;
869 if (!extract_name(header
, plen
, &p
, name
, 1, 10))
874 /* if more labels than in RRsig name, hash *.<no labels in rrsig labels field> 4035 5.3.2 */
875 if (labels
< name_labels
)
878 for (k
= name_labels
- labels
; k
!= 0; k
--)
880 while (*name_start
!= '.' && *name_start
!= 0)
882 if (k
!= 1 && *name_start
== '.')
887 *wildcard_out
= name_start
+1;
893 wire_len
= to_wire(name_start
);
894 hash
->update(ctx
, (unsigned int)wire_len
, (unsigned char *)name_start
);
895 hash
->update(ctx
, 4, p
); /* class and type */
896 hash
->update(ctx
, 4, (unsigned char *)&nsigttl
);
898 p
+= 8; /* skip class, type, ttl */
900 if (!CHECK_LEN(header
, p
, plen
, rdlen
))
905 /* canonicalise rdata and calculate length of same, use name buffer as workspace */
908 for (len
= 0; (seg
= get_rdata(header
, plen
, end
, name
, MAXDNAME
, &cp
, &dp
)) != 0; len
+= seg
);
911 hash
->update(ctx
, 2, (unsigned char *)&len
);
913 /* Now canonicalise again and digest. */
916 while ((seg
= get_rdata(header
, plen
, end
, name
, MAXDNAME
, &cp
, &dp
)))
917 hash
->update(ctx
, seg
, (unsigned char *)name
);
919 hash
->update(ctx
, end
- cp
, cp
);
922 hash
->digest(ctx
, hash
->digest_size
, digest
);
924 /* namebuff used for workspace above, restore to leave unchanged on exit */
925 p
= (unsigned char*)(rrset
[0]);
926 extract_name(header
, plen
, &p
, name
, 1, 0);
930 if (algo_in
== algo
&& keytag_in
== key_tag
&&
931 verify(key
, keylen
, sig
, sig_len
, digest
, hash
->digest_size
, algo
))
936 /* iterate through all possible keys 4035 5.3.1 */
937 for (; crecp
; crecp
= cache_find_by_name(crecp
, keyname
, now
, F_DNSKEY
))
938 if (crecp
->addr
.key
.algo
== algo
&&
939 crecp
->addr
.key
.keytag
== key_tag
&&
940 crecp
->uid
== (unsigned int)class &&
941 verify(crecp
->addr
.key
.keydata
, crecp
->addr
.key
.keylen
, sig
, sig_len
, digest
, hash
->digest_size
, algo
))
942 return (labels
< name_labels
) ? STAT_SECURE_WILDCARD
: STAT_SECURE
;
949 /* The DNS packet is expected to contain the answer to a DNSKEY query.
950 Put all DNSKEYs in the answer which are valid into the cache.
952 STAT_SECURE At least one valid DNSKEY found and in cache.
953 STAT_BOGUS No DNSKEYs found, which can be validated with DS,
954 or self-sign for DNSKEY RRset is not valid, bad packet.
955 STAT_NEED_DS DS records to validate a key not found, name in keyname
957 int dnssec_validate_by_ds(time_t now
, struct dns_header
*header
, size_t plen
, char *name
, char *keyname
, int class)
959 unsigned char *psave
, *p
= (unsigned char *)(header
+1);
960 struct crec
*crecp
, *recp1
;
961 int rc
, j
, qtype
, qclass
, ttl
, rdlen
, flags
, algo
, valid
, keytag
, type_covered
;
962 struct blockdata
*key
;
965 if (ntohs(header
->qdcount
) != 1 ||
966 !extract_name(header
, plen
, &p
, name
, 1, 4))
972 if (qtype
!= T_DNSKEY
|| qclass
!= class || ntohs(header
->ancount
) == 0)
975 /* See if we have cached a DS record which validates this key */
976 if (!(crecp
= cache_find_by_name(NULL
, name
, now
, F_DS
)))
978 strcpy(keyname
, name
);
982 /* If we've cached that DS provably doesn't exist, result must be INSECURE */
983 if (crecp
->flags
& F_NEG
)
984 return STAT_INSECURE
;
986 /* NOTE, we need to find ONE DNSKEY which matches the DS */
987 for (valid
= 0, j
= ntohs(header
->ancount
); j
!= 0 && !valid
; j
--)
989 /* Ensure we have type, class TTL and length */
990 if (!(rc
= extract_name(header
, plen
, &p
, name
, 0, 10)))
991 return STAT_BOGUS
; /* bad packet */
998 if (!CHECK_LEN(header
, p
, plen
, rdlen
) || rdlen
< 4)
999 return STAT_BOGUS
; /* bad packet */
1001 if (qclass
!= class || qtype
!= T_DNSKEY
|| rc
== 2)
1013 keytag
= dnskey_keytag(algo
, flags
, p
, rdlen
- 4);
1016 /* key must have zone key flag set */
1018 key
= blockdata_alloc((char*)p
, rdlen
- 4);
1022 if (!ADD_RDLEN(header
, p
, plen
, rdlen
))
1025 blockdata_free(key
);
1026 return STAT_BOGUS
; /* bad packet */
1029 /* No zone key flag or malloc failure */
1033 for (recp1
= crecp
; recp1
; recp1
= cache_find_by_name(recp1
, name
, now
, F_DS
))
1036 unsigned char *digest
, *ds_digest
;
1037 const struct nettle_hash
*hash
;
1039 if (recp1
->addr
.ds
.algo
== algo
&&
1040 recp1
->addr
.ds
.keytag
== keytag
&&
1041 recp1
->uid
== (unsigned int)class &&
1042 (hash
= hash_find(ds_digest_name(recp1
->addr
.ds
.digest
))) &&
1043 hash_init(hash
, &ctx
, &digest
))
1046 int wire_len
= to_wire(name
);
1048 /* Note that digest may be different between DSs, so
1049 we can't move this outside the loop. */
1050 hash
->update(ctx
, (unsigned int)wire_len
, (unsigned char *)name
);
1051 hash
->update(ctx
, (unsigned int)rdlen
, psave
);
1052 hash
->digest(ctx
, hash
->digest_size
, digest
);
1056 if (recp1
->addr
.ds
.keylen
== (int)hash
->digest_size
&&
1057 (ds_digest
= blockdata_retrieve(recp1
->addr
.key
.keydata
, recp1
->addr
.ds
.keylen
, NULL
)) &&
1058 memcmp(ds_digest
, digest
, recp1
->addr
.ds
.keylen
) == 0 &&
1059 validate_rrset(now
, header
, plen
, class, T_DNSKEY
, name
, keyname
, NULL
, key
, rdlen
- 4, algo
, keytag
) == STAT_SECURE
)
1066 blockdata_free(key
);
1071 /* DNSKEY RRset determined to be OK, now cache it and the RRsigs that sign it. */
1072 cache_start_insert();
1074 p
= skip_questions(header
, plen
);
1076 for (j
= ntohs(header
->ancount
); j
!= 0; j
--)
1078 /* Ensure we have type, class TTL and length */
1079 if (!(rc
= extract_name(header
, plen
, &p
, name
, 0, 10)))
1080 return STAT_INSECURE
; /* bad packet */
1083 GETSHORT(qclass
, p
);
1087 if (!CHECK_LEN(header
, p
, plen
, rdlen
))
1088 return STAT_BOGUS
; /* bad packet */
1090 if (qclass
== class && rc
== 1)
1094 if (qtype
== T_DNSKEY
)
1097 return STAT_BOGUS
; /* bad packet */
1103 keytag
= dnskey_keytag(algo
, flags
, p
, rdlen
- 4);
1105 /* Cache needs to known class for DNSSEC stuff */
1106 a
.addr
.dnssec
.class = class;
1108 if ((key
= blockdata_alloc((char*)p
, rdlen
- 4)))
1110 if (!(recp1
= cache_insert(name
, &a
, now
, ttl
, F_FORWARD
| F_DNSKEY
| F_DNSSECOK
)))
1111 blockdata_free(key
);
1114 a
.addr
.keytag
= keytag
;
1115 log_query(F_NOEXTRA
| F_KEYTAG
| F_UPSTREAM
, name
, &a
, "DNSKEY keytag %u");
1117 recp1
->addr
.key
.keylen
= rdlen
- 4;
1118 recp1
->addr
.key
.keydata
= key
;
1119 recp1
->addr
.key
.algo
= algo
;
1120 recp1
->addr
.key
.keytag
= keytag
;
1121 recp1
->addr
.key
.flags
= flags
;
1125 else if (qtype
== T_RRSIG
)
1127 /* RRSIG, cache if covers DNSKEY RRset */
1129 return STAT_BOGUS
; /* bad packet */
1131 GETSHORT(type_covered
, p
);
1133 if (type_covered
== T_DNSKEY
)
1135 a
.addr
.dnssec
.class = class;
1136 a
.addr
.dnssec
.type
= type_covered
;
1139 p
+= 13; /* labels, orig_ttl, expiration, inception */
1140 GETSHORT(keytag
, p
);
1141 if ((key
= blockdata_alloc((char*)psave
, rdlen
)))
1143 if (!(crecp
= cache_insert(name
, &a
, now
, ttl
, F_FORWARD
| F_DNSKEY
| F_DS
)))
1144 blockdata_free(key
);
1147 crecp
->addr
.sig
.keydata
= key
;
1148 crecp
->addr
.sig
.keylen
= rdlen
;
1149 crecp
->addr
.sig
.keytag
= keytag
;
1150 crecp
->addr
.sig
.type_covered
= type_covered
;
1151 crecp
->addr
.sig
.algo
= algo
;
1160 if (!ADD_RDLEN(header
, p
, plen
, rdlen
))
1161 return STAT_BOGUS
; /* bad packet */
1164 /* commit cache insert. */
1169 log_query(F_NOEXTRA
| F_UPSTREAM
, name
, NULL
, "BOGUS DNSKEY");
1173 /* The DNS packet is expected to contain the answer to a DS query
1174 Put all DSs in the answer which are valid into the cache.
1176 STAT_SECURE At least one valid DS found and in cache.
1177 STAT_NO_DS It's proved there's no DS here.
1178 STAT_NO_NS It's proved there's no DS _or_ NS here.
1179 STAT_BOGUS no DS in reply or not signed, fails validation, bad packet.
1180 STAT_NEED_DNSKEY DNSKEY records to validate a DS not found, name in keyname
1183 int dnssec_validate_ds(time_t now
, struct dns_header
*header
, size_t plen
, char *name
, char *keyname
, int class)
1185 unsigned char *p
= (unsigned char *)(header
+1);
1186 int qtype
, qclass
, val
, i
, neganswer
, nons
;
1188 if (ntohs(header
->qdcount
) != 1 ||
1189 !(p
= skip_name(p
, header
, plen
, 4)))
1193 GETSHORT(qclass
, p
);
1195 if (qtype
!= T_DS
|| qclass
!= class)
1198 val
= dnssec_validate_reply(now
, header
, plen
, name
, keyname
, NULL
, &neganswer
, &nons
);
1199 /* Note dnssec_validate_reply() will have cached positive answers */
1201 if (val
== STAT_NO_SIG
|| val
== STAT_INSECURE
)
1204 p
= (unsigned char *)(header
+1);
1205 extract_name(header
, plen
, &p
, name
, 1, 4);
1206 p
+= 4; /* qtype, qclass */
1208 if (!(p
= skip_section(p
, ntohs(header
->ancount
), header
, plen
)))
1211 if (val
== STAT_BOGUS
)
1213 log_query(F_NOEXTRA
| F_UPSTREAM
, name
, NULL
, "BOGUS DS");
1217 /* By here, the answer is proved secure, and a positive answer has been cached. */
1218 if (val
== STAT_SECURE
&& neganswer
)
1220 int rdlen
, flags
= F_FORWARD
| F_DS
| F_NEG
| F_DNSSECOK
;
1221 unsigned long ttl
, minttl
= ULONG_MAX
;
1224 if (RCODE(header
) == NXDOMAIN
)
1225 flags
|= F_NXDOMAIN
;
1227 /* We only cache validated DS records, DNSSECOK flag hijacked
1228 to store presence/absence of NS. */
1230 flags
&= ~F_DNSSECOK
;
1232 for (i
= ntohs(header
->nscount
); i
!= 0; i
--)
1234 if (!(p
= skip_name(p
, header
, plen
, 0)))
1238 GETSHORT(qclass
, p
);
1242 if (!CHECK_LEN(header
, p
, plen
, rdlen
))
1243 return STAT_BOGUS
; /* bad packet */
1245 if (qclass
!= class || qtype
!= T_SOA
)
1255 if (!(p
= skip_name(p
, header
, plen
, 0)))
1258 if (!(p
= skip_name(p
, header
, plen
, 20)))
1260 p
+= 16; /* SERIAL REFRESH RETRY EXPIRE */
1262 GETLONG(ttl
, p
); /* minTTL */
1271 cache_start_insert();
1273 a
.addr
.dnssec
.class = class;
1274 cache_insert(name
, &a
, now
, ttl
, flags
);
1278 log_query(F_NOEXTRA
| F_UPSTREAM
, name
, NULL
, nons
? "no delegation" : "no DS");
1281 return nons
? STAT_NO_NS
: STAT_NO_DS
;
1288 static int hostname_cmp(const char *a
, const char *b
)
1290 char *sa
, *ea
, *ca
, *sb
, *eb
, *cb
;
1291 unsigned char ac
, bc
;
1293 sa
= ea
= (char *)a
+ strlen(a
);
1294 sb
= eb
= (char *)b
+ strlen(b
);
1298 while (sa
!= a
&& *(sa
-1) != '.')
1301 while (sb
!= b
&& *(sb
-1) != '.')
1320 ac
= (unsigned char) *ca
++;
1321 bc
= (unsigned char) *cb
++;
1323 if (ac
>= 'A' && ac
<= 'Z')
1325 if (bc
>= 'A' && bc
<= 'Z')
1351 /* Find all the NSEC or NSEC3 records in a reply.
1352 return an array of pointers to them. */
1353 static int find_nsec_records(struct dns_header
*header
, size_t plen
, unsigned char ***nsecsetp
, int *nsecsetl
, int class_reqd
)
1355 static unsigned char **nsecset
= NULL
;
1356 static int nsecset_sz
= 0;
1359 unsigned char *p
= skip_questions(header
, plen
);
1360 int type
, class, rdlen
, i
, nsecs_found
;
1362 /* Move to NS section */
1363 if (!p
|| !(p
= skip_section(p
, ntohs(header
->ancount
), header
, plen
)))
1366 for (nsecs_found
= 0, i
= ntohs(header
->nscount
); i
!= 0; i
--)
1368 unsigned char *pstart
= p
;
1370 if (!(p
= skip_name(p
, header
, plen
, 10)))
1378 if (class == class_reqd
&& (type
== T_NSEC
|| type
== T_NSEC3
))
1380 /* No mixed NSECing 'round here, thankyouverymuch */
1381 if (type_found
== T_NSEC
&& type
== T_NSEC3
)
1383 if (type_found
== T_NSEC3
&& type
== T_NSEC
)
1388 if (!expand_workspace(&nsecset
, &nsecset_sz
, nsecs_found
))
1391 nsecset
[nsecs_found
++] = pstart
;
1394 if (!ADD_RDLEN(header
, p
, plen
, rdlen
))
1398 *nsecsetp
= nsecset
;
1399 *nsecsetl
= nsecs_found
;
1404 static int prove_non_existence_nsec(struct dns_header
*header
, size_t plen
, unsigned char **nsecs
, int nsec_count
,
1405 char *workspace1
, char *workspace2
, char *name
, int type
, int *nons
)
1408 unsigned char *p
, *psave
;
1409 int offset
= (type
& 0xff) >> 3;
1410 int mask
= 0x80 >> (type
& 0x07);
1415 /* Find NSEC record that proves name doesn't exist */
1416 for (i
= 0; i
< nsec_count
; i
++)
1419 if (!extract_name(header
, plen
, &p
, workspace1
, 1, 10))
1421 p
+= 8; /* class, type, TTL */
1424 if (!extract_name(header
, plen
, &p
, workspace2
, 1, 10))
1427 rc
= hostname_cmp(workspace1
, name
);
1431 /* 4035 para 5.4. Last sentence */
1432 if (type
== T_NSEC
|| type
== T_RRSIG
)
1435 /* NSEC with the same name as the RR we're testing, check
1436 that the type in question doesn't appear in the type map */
1438 /* rdlen is now length of type map, and p points to it */
1440 /* If we can prove that there's no NS record, return that information. */
1441 if (nons
&& rdlen
>= 2 && p
[0] == 0 && (p
[2] & (0x80 >> T_NS
)) == 0)
1446 if (!CHECK_LEN(header
, p
, plen
, rdlen
))
1449 if (p
[0] == type
>> 8)
1451 /* Does the NSEC say our type exists? */
1452 if (offset
< p
[1] && (p
[offset
+2] & mask
) != 0)
1455 break; /* finshed checking */
1466 /* Normal case, name falls between NSEC name and next domain name,
1467 wrap around case, name falls between NSEC name (rc == -1) and end */
1468 if (hostname_cmp(workspace2
, name
) == 1 || hostname_cmp(workspace1
, workspace2
) == 1)
1473 /* wrap around case, name falls between start and next domain name */
1474 if (hostname_cmp(workspace1
, workspace2
) == 1 && hostname_cmp(workspace2
, name
) == 1)
1482 /* return digest length, or zero on error */
1483 static int hash_name(char *in
, unsigned char **out
, struct nettle_hash
const *hash
,
1484 unsigned char *salt
, int salt_len
, int iterations
)
1487 unsigned char *digest
;
1490 if (!hash_init(hash
, &ctx
, &digest
))
1493 hash
->update(ctx
, to_wire(in
), (unsigned char *)in
);
1494 hash
->update(ctx
, salt_len
, salt
);
1495 hash
->digest(ctx
, hash
->digest_size
, digest
);
1497 for(i
= 0; i
< iterations
; i
++)
1499 hash
->update(ctx
, hash
->digest_size
, digest
);
1500 hash
->update(ctx
, salt_len
, salt
);
1501 hash
->digest(ctx
, hash
->digest_size
, digest
);
1507 return hash
->digest_size
;
1510 /* Decode base32 to first "." or end of string */
1511 static int base32_decode(char *in
, unsigned char *out
)
1513 int oc
, on
, c
, mask
, i
;
1514 unsigned char *p
= out
;
1516 for (c
= *in
, oc
= 0, on
= 0; c
!= 0 && c
!= '.'; c
= *++in
)
1518 if (c
>= '0' && c
<= '9')
1520 else if (c
>= 'a' && c
<= 'v')
1522 else if (c
>= 'A' && c
<= 'V')
1527 for (mask
= 0x10, i
= 0; i
< 5; i
++)
1532 if (((++on
) & 7) == 0)
1544 static int check_nsec3_coverage(struct dns_header
*header
, size_t plen
, int digest_len
, unsigned char *digest
, int type
,
1545 char *workspace1
, char *workspace2
, unsigned char **nsecs
, int nsec_count
, int *nons
)
1547 int i
, hash_len
, salt_len
, base32_len
, rdlen
;
1548 unsigned char *p
, *psave
;
1550 for (i
= 0; i
< nsec_count
; i
++)
1553 if (!extract_name(header
, plen
, &p
, workspace1
, 1, 0) ||
1554 !(base32_len
= base32_decode(workspace1
, (unsigned char *)workspace2
)))
1557 p
+= 8; /* class, type, TTL */
1560 p
+= 4; /* algo, flags, iterations */
1561 salt_len
= *p
++; /* salt_len */
1562 p
+= salt_len
; /* salt */
1563 hash_len
= *p
++; /* p now points to next hashed name */
1565 if (!CHECK_LEN(header
, p
, plen
, hash_len
))
1568 if (digest_len
== base32_len
&& hash_len
== base32_len
)
1570 int rc
= memcmp(workspace2
, digest
, digest_len
);
1574 /* We found an NSEC3 whose hashed name exactly matches the query, so
1575 we just need to check the type map. p points to the RR data for the record. */
1577 int offset
= (type
& 0xff) >> 3;
1578 int mask
= 0x80 >> (type
& 0x07);
1580 p
+= hash_len
; /* skip next-domain hash */
1583 if (!CHECK_LEN(header
, p
, plen
, rdlen
))
1586 /* If we can prove that there's no NS record, return that information. */
1587 if (nons
&& rdlen
>= 2 && p
[0] == 0 && (p
[2] & (0x80 >> T_NS
)) == 0)
1592 if (p
[0] == type
>> 8)
1594 /* Does the NSEC3 say our type exists? */
1595 if (offset
< p
[1] && (p
[offset
+2] & mask
) != 0)
1598 break; /* finshed checking */
1609 /* Normal case, hash falls between NSEC3 name-hash and next domain name-hash,
1610 wrap around case, name-hash falls between NSEC3 name-hash and end */
1611 if (memcmp(p
, digest
, digest_len
) > 0 || memcmp(workspace2
, p
, digest_len
) > 0)
1616 /* wrap around case, name falls between start and next domain name */
1617 if (memcmp(workspace2
, p
, digest_len
) > 0 && memcmp(p
, digest
, digest_len
) > 0)
1625 static int prove_non_existence_nsec3(struct dns_header
*header
, size_t plen
, unsigned char **nsecs
, int nsec_count
,
1626 char *workspace1
, char *workspace2
, char *name
, int type
, char *wildname
, int *nons
)
1628 unsigned char *salt
, *p
, *digest
;
1629 int digest_len
, i
, iterations
, salt_len
, base32_len
, algo
= 0;
1630 struct nettle_hash
const *hash
;
1631 char *closest_encloser
, *next_closest
, *wildcard
;
1636 /* Look though the NSEC3 records to find the first one with
1637 an algorithm we support (currently only algo == 1).
1639 Take the algo, iterations, and salt of that record
1640 as the ones we're going to use, and prune any
1641 that don't match. */
1643 for (i
= 0; i
< nsec_count
; i
++)
1645 if (!(p
= skip_name(nsecs
[i
], header
, plen
, 15)))
1646 return STAT_BOGUS
; /* bad packet */
1648 p
+= 10; /* type, class, TTL, rdlen */
1652 break; /* known algo */
1655 /* No usable NSEC3s */
1656 if (i
== nsec_count
)
1660 GETSHORT (iterations
, p
);
1663 if (!CHECK_LEN(header
, salt
, plen
, salt_len
))
1664 return STAT_BOGUS
; /* bad packet */
1666 /* Now prune so we only have NSEC3 records with same iterations, salt and algo */
1667 for (i
= 0; i
< nsec_count
; i
++)
1669 unsigned char *nsec3p
= nsecs
[i
];
1672 nsecs
[i
] = NULL
; /* Speculative, will be restored if OK. */
1674 if (!(p
= skip_name(nsec3p
, header
, plen
, 15)))
1675 return STAT_BOGUS
; /* bad packet */
1677 p
+= 10; /* type, class, TTL, rdlen */
1684 GETSHORT(this_iter
, p
);
1685 if (this_iter
!= iterations
)
1688 if (salt_len
!= *p
++)
1691 if (!CHECK_LEN(header
, p
, plen
, salt_len
))
1692 return STAT_BOGUS
; /* bad packet */
1694 if (memcmp(p
, salt
, salt_len
) != 0)
1697 /* All match, put the pointer back */
1701 /* Algo is checked as 1 above */
1702 if (!(hash
= hash_find("sha1")))
1705 if ((digest_len
= hash_name(name
, &digest
, hash
, salt
, salt_len
, iterations
)) == 0)
1708 if (check_nsec3_coverage(header
, plen
, digest_len
, digest
, type
, workspace1
, workspace2
, nsecs
, nsec_count
, nons
))
1711 /* Can't find an NSEC3 which covers the name directly, we need the "closest encloser NSEC3"
1712 or an answer inferred from a wildcard record. */
1713 closest_encloser
= name
;
1714 next_closest
= NULL
;
1718 if (*closest_encloser
== '.')
1721 if (wildname
&& hostname_isequal(closest_encloser
, wildname
))
1724 if ((digest_len
= hash_name(closest_encloser
, &digest
, hash
, salt
, salt_len
, iterations
)) == 0)
1727 for (i
= 0; i
< nsec_count
; i
++)
1730 if (!extract_name(header
, plen
, &p
, workspace1
, 1, 0) ||
1731 !(base32_len
= base32_decode(workspace1
, (unsigned char *)workspace2
)))
1734 if (digest_len
== base32_len
&&
1735 memcmp(digest
, workspace2
, digest_len
) == 0)
1739 if (i
!= nsec_count
)
1742 next_closest
= closest_encloser
;
1744 while ((closest_encloser
= strchr(closest_encloser
, '.')));
1746 if (!closest_encloser
)
1749 /* Look for NSEC3 that proves the non-existence of the next-closest encloser */
1750 if ((digest_len
= hash_name(next_closest
, &digest
, hash
, salt
, salt_len
, iterations
)) == 0)
1753 if (!check_nsec3_coverage(header
, plen
, digest_len
, digest
, type
, workspace1
, workspace2
, nsecs
, nsec_count
, NULL
))
1756 /* Finally, check that there's no seat of wildcard synthesis */
1759 if (!(wildcard
= strchr(next_closest
, '.')) || wildcard
== next_closest
)
1765 if ((digest_len
= hash_name(wildcard
, &digest
, hash
, salt
, salt_len
, iterations
)) == 0)
1768 if (!check_nsec3_coverage(header
, plen
, digest_len
, digest
, type
, workspace1
, workspace2
, nsecs
, nsec_count
, NULL
))
1775 /* Validate all the RRsets in the answer and authority sections of the reply (4035:3.2.3) */
1776 /* Returns are the same as validate_rrset, plus the class if the missing key is in *class */
1777 int dnssec_validate_reply(time_t now
, struct dns_header
*header
, size_t plen
, char *name
, char *keyname
,
1778 int *class, int *neganswer
, int *nons
)
1780 unsigned char *ans_start
, *qname
, *p1
, *p2
, **nsecs
;
1781 int type1
, class1
, rdlen1
, type2
, class2
, rdlen2
, qclass
, qtype
;
1782 int i
, j
, rc
, nsec_count
, cname_count
= CNAME_CHAIN
;
1783 int nsec_type
= 0, have_answer
= 0;
1788 if (RCODE(header
) == SERVFAIL
|| ntohs(header
->qdcount
) != 1)
1791 if (RCODE(header
) != NXDOMAIN
&& RCODE(header
) != NOERROR
)
1792 return STAT_INSECURE
;
1794 qname
= p1
= (unsigned char *)(header
+1);
1796 if (!extract_name(header
, plen
, &p1
, name
, 1, 4))
1799 GETSHORT(qtype
, p1
);
1800 GETSHORT(qclass
, p1
);
1806 /* Can't validate an RRISG query */
1807 if (qtype
== T_RRSIG
)
1808 return STAT_INSECURE
;
1811 for (j
= ntohs(header
->ancount
); j
!= 0; j
--)
1813 /* leave pointer to missing name in qname */
1815 if (!(rc
= extract_name(header
, plen
, &p1
, name
, 0, 10)))
1816 return STAT_BOGUS
; /* bad packet */
1818 GETSHORT(type2
, p1
);
1819 GETSHORT(class2
, p1
);
1821 GETSHORT(rdlen2
, p1
);
1823 if (rc
== 1 && qclass
== class2
)
1825 /* Do we have an answer for the question? */
1831 else if (type2
== T_CNAME
)
1836 if (!cname_count
-- || !extract_name(header
, plen
, &p1
, name
, 1, 0))
1844 if (!ADD_RDLEN(header
, p1
, plen
, rdlen2
))
1848 if (neganswer
&& !have_answer
)
1851 /* No data, therefore no sigs */
1852 if (ntohs(header
->ancount
) + ntohs(header
->nscount
) == 0)
1855 for (p1
= ans_start
, i
= 0; i
< ntohs(header
->ancount
) + ntohs(header
->nscount
); i
++)
1857 if (!extract_name(header
, plen
, &p1
, name
, 1, 10))
1858 return STAT_BOGUS
; /* bad packet */
1860 GETSHORT(type1
, p1
);
1861 GETSHORT(class1
, p1
);
1863 GETSHORT(rdlen1
, p1
);
1865 /* Don't try and validate RRSIGs! */
1866 if (type1
!= T_RRSIG
)
1868 /* Check if we've done this RRset already */
1869 for (p2
= ans_start
, j
= 0; j
< i
; j
++)
1871 if (!(rc
= extract_name(header
, plen
, &p2
, name
, 0, 10)))
1872 return STAT_BOGUS
; /* bad packet */
1874 GETSHORT(type2
, p2
);
1875 GETSHORT(class2
, p2
);
1877 GETSHORT(rdlen2
, p2
);
1879 if (type2
== type1
&& class2
== class1
&& rc
== 1)
1880 break; /* Done it before: name, type, class all match. */
1882 if (!ADD_RDLEN(header
, p2
, plen
, rdlen2
))
1886 /* Not done, validate now */
1889 int ttl
, keytag
, algo
, digest
, type_covered
;
1890 unsigned char *psave
;
1892 struct blockdata
*key
;
1895 int have_wildcard
= 0;
1897 rc
= validate_rrset(now
, header
, plen
, class1
, type1
, name
, keyname
, &wildname
, NULL
, 0, 0, 0);
1899 if (rc
== STAT_SECURE_WILDCARD
)
1903 /* An attacker replay a wildcard answer with a different
1904 answer and overlay a genuine RR. To prove this
1905 hasn't happened, the answer must prove that
1906 the gennuine record doesn't exist. Check that here. */
1907 if (!nsec_type
&& !(nsec_type
= find_nsec_records(header
, plen
, &nsecs
, &nsec_count
, class1
)))
1908 return STAT_BOGUS
; /* No NSECs or bad packet */
1910 if (nsec_type
== T_NSEC
)
1911 rc
= prove_non_existence_nsec(header
, plen
, nsecs
, nsec_count
, daemon
->workspacename
, keyname
, name
, type1
, NULL
);
1913 rc
= prove_non_existence_nsec3(header
, plen
, nsecs
, nsec_count
, daemon
->workspacename
,
1914 keyname
, name
, type1
, wildname
, NULL
);
1916 if (rc
!= STAT_SECURE
)
1919 else if (rc
!= STAT_SECURE
)
1922 *class = class1
; /* Class for DS or DNSKEY */
1926 /* Cache RRsigs in answer section, and if we just validated a DS RRset, cache it */
1927 cache_start_insert();
1929 for (p2
= ans_start
, j
= 0; j
< ntohs(header
->ancount
); j
++)
1931 if (!(rc
= extract_name(header
, plen
, &p2
, name
, 0, 10)))
1932 return STAT_BOGUS
; /* bad packet */
1934 GETSHORT(type2
, p2
);
1935 GETSHORT(class2
, p2
);
1937 GETSHORT(rdlen2
, p2
);
1939 if (!CHECK_LEN(header
, p2
, plen
, rdlen2
))
1940 return STAT_BOGUS
; /* bad packet */
1942 if (class2
== class1
&& rc
== 1)
1946 if (type1
== T_DS
&& type2
== T_DS
)
1949 return STAT_BOGUS
; /* bad packet */
1951 GETSHORT(keytag
, p2
);
1955 /* Cache needs to known class for DNSSEC stuff */
1956 a
.addr
.dnssec
.class = class2
;
1958 if ((key
= blockdata_alloc((char*)p2
, rdlen2
- 4)))
1960 if (!(crecp
= cache_insert(name
, &a
, now
, ttl
, F_FORWARD
| F_DS
| F_DNSSECOK
)))
1961 blockdata_free(key
);
1964 a
.addr
.keytag
= keytag
;
1965 log_query(F_NOEXTRA
| F_KEYTAG
| F_UPSTREAM
, name
, &a
, "DS keytag %u");
1966 crecp
->addr
.ds
.digest
= digest
;
1967 crecp
->addr
.ds
.keydata
= key
;
1968 crecp
->addr
.ds
.algo
= algo
;
1969 crecp
->addr
.ds
.keytag
= keytag
;
1970 crecp
->addr
.ds
.keylen
= rdlen2
- 4;
1974 else if (type2
== T_RRSIG
)
1977 return STAT_BOGUS
; /* bad packet */
1979 GETSHORT(type_covered
, p2
);
1981 if (type_covered
== type1
&&
1982 (type_covered
== T_A
|| type_covered
== T_AAAA
||
1983 type_covered
== T_CNAME
|| type_covered
== T_DS
||
1984 type_covered
== T_DNSKEY
|| type_covered
== T_PTR
))
1986 a
.addr
.dnssec
.type
= type_covered
;
1987 a
.addr
.dnssec
.class = class1
;
1990 p2
+= 13; /* labels, orig_ttl, expiration, inception */
1991 GETSHORT(keytag
, p2
);
1993 /* We don't cache sigs for wildcard answers, because to reproduce the
1994 answer from the cache will require one or more NSEC/NSEC3 records
1995 which we don't cache. The lack of the RRSIG ensures that a query for
1996 this RRset asking for a secure answer will always be forwarded. */
1997 if (!have_wildcard
&& (key
= blockdata_alloc((char*)psave
, rdlen2
)))
1999 if (!(crecp
= cache_insert(name
, &a
, now
, ttl
, F_FORWARD
| F_DNSKEY
| F_DS
)))
2000 blockdata_free(key
);
2003 crecp
->addr
.sig
.keydata
= key
;
2004 crecp
->addr
.sig
.keylen
= rdlen2
;
2005 crecp
->addr
.sig
.keytag
= keytag
;
2006 crecp
->addr
.sig
.type_covered
= type_covered
;
2007 crecp
->addr
.sig
.algo
= algo
;
2016 if (!ADD_RDLEN(header
, p2
, plen
, rdlen2
))
2017 return STAT_BOGUS
; /* bad packet */
2024 if (!ADD_RDLEN(header
, p1
, plen
, rdlen1
))
2028 /* OK, all the RRsets validate, now see if we have a NODATA or NXDOMAIN reply */
2032 /* NXDOMAIN or NODATA reply, prove that (name, class1, type1) can't exist */
2033 /* First marshall the NSEC records, if we've not done it previously */
2034 if (!nsec_type
&& !(nsec_type
= find_nsec_records(header
, plen
, &nsecs
, &nsec_count
, qclass
)))
2035 return STAT_NO_SIG
; /* No NSECs, this is probably a dangling CNAME pointing into
2036 an unsigned zone. Return STAT_NO_SIG to cause this to be proved. */
2038 /* Get name of missing answer */
2039 if (!extract_name(header
, plen
, &qname
, name
, 1, 0))
2042 if (nsec_type
== T_NSEC
)
2043 return prove_non_existence_nsec(header
, plen
, nsecs
, nsec_count
, daemon
->workspacename
, keyname
, name
, qtype
, nons
);
2045 return prove_non_existence_nsec3(header
, plen
, nsecs
, nsec_count
, daemon
->workspacename
, keyname
, name
, qtype
, NULL
, nons
);
2048 /* Chase the CNAME chain in the packet until the first record which _doesn't validate.
2049 Needed for proving answer in unsigned space.
2052 STAT_INSECURE - name of first non-secure record in name
2054 int dnssec_chase_cname(time_t now
, struct dns_header
*header
, size_t plen
, char *name
, char *keyname
)
2056 unsigned char *p
= (unsigned char *)(header
+1);
2057 int type
, class, qclass
, rdlen
, j
, rc
;
2058 int cname_count
= CNAME_CHAIN
;
2061 if (!extract_name(header
, plen
, &p
, name
, 1, 4))
2065 GETSHORT(qclass
, p
);
2069 for (j
= ntohs(header
->ancount
); j
!= 0; j
--)
2071 if (!(rc
= extract_name(header
, plen
, &p
, name
, 0, 10)))
2072 return STAT_BOGUS
; /* bad packet */
2079 /* Not target, loop */
2080 if (rc
== 2 || qclass
!= class)
2082 if (!ADD_RDLEN(header
, p
, plen
, rdlen
))
2087 /* Got to end of CNAME chain. */
2088 if (type
!= T_CNAME
)
2089 return STAT_INSECURE
;
2091 /* validate CNAME chain, return if insecure or need more data */
2092 rc
= validate_rrset(now
, header
, plen
, class, type
, name
, keyname
, NULL
, NULL
, 0, 0, 0);
2093 if (rc
!= STAT_SECURE
)
2095 if (rc
== STAT_NO_SIG
)
2100 /* Loop down CNAME chain/ */
2101 if (!cname_count
-- ||
2102 !extract_name(header
, plen
, &p
, name
, 1, 0) ||
2103 !(p
= skip_questions(header
, plen
)))
2109 /* End of CNAME chain */
2110 return STAT_INSECURE
;
2115 /* Compute keytag (checksum to quickly index a key). See RFC4034 */
2116 int dnskey_keytag(int alg
, int flags
, unsigned char *key
, int keylen
)
2120 /* Algorithm 1 (RSAMD5) has a different (older) keytag calculation algorithm.
2121 See RFC4034, Appendix B.1 */
2122 return key
[keylen
-4] * 256 + key
[keylen
-3];
2126 unsigned long ac
= flags
+ 0x300 + alg
;
2129 for (i
= 0; i
< keylen
; ++i
)
2130 ac
+= (i
& 1) ? key
[i
] : key
[i
] << 8;
2132 ac
+= (ac
>> 16) & 0xffff;
2137 size_t dnssec_generate_query(struct dns_header
*header
, char *end
, char *name
, int class, int type
, union mysockaddr
*addr
)
2140 char *types
= querystr("dnssec-query", type
);
2142 if (addr
->sa
.sa_family
== AF_INET
)
2143 log_query(F_NOEXTRA
| F_DNSSEC
| F_IPV4
, name
, (struct all_addr
*)&addr
->in
.sin_addr
, types
);
2146 log_query(F_NOEXTRA
| F_DNSSEC
| F_IPV6
, name
, (struct all_addr
*)&addr
->in6
.sin6_addr
, types
);
2149 header
->qdcount
= htons(1);
2150 header
->ancount
= htons(0);
2151 header
->nscount
= htons(0);
2152 header
->arcount
= htons(0);
2154 header
->hb3
= HB3_RD
;
2155 SET_OPCODE(header
, QUERY
);
2156 /* For debugging, set Checking Disabled, otherwise, have the upstream check too,
2157 this allows it to select auth servers when one is returning bad data. */
2158 header
->hb4
= option_bool(OPT_DNSSEC_DEBUG
) ? HB4_CD
: 0;
2160 /* ID filled in later */
2162 p
= (unsigned char *)(header
+1);
2164 p
= do_rfc1035_name(p
, name
);
2169 return add_do_bit(header
, p
- (unsigned char *)header
, end
);
2172 /* Go through a domain name, find "pointers" and fix them up based on how many bytes
2173 we've chopped out of the packet, or check they don't point into an elided part. */
2174 static int check_name(unsigned char **namep
, struct dns_header
*header
, size_t plen
, int fixup
, unsigned char **rrs
, int rr_count
)
2176 unsigned char *ansp
= *namep
;
2180 unsigned int label_type
;
2182 if (!CHECK_LEN(header
, ansp
, plen
, 1))
2185 label_type
= (*ansp
) & 0xc0;
2187 if (label_type
== 0xc0)
2189 /* pointer for compression. */
2190 unsigned int offset
;
2194 if (!CHECK_LEN(header
, ansp
, plen
, 2))
2197 offset
= ((*ansp
++) & 0x3f) << 8;
2200 p
= offset
+ (unsigned char *)header
;
2202 for (i
= 0; i
< rr_count
; i
++)
2207 offset
-= rrs
[i
] - rrs
[i
-1];
2209 /* does the pointer end up in an elided RR? */
2213 /* No, scale the pointer */
2217 *ansp
++ = (offset
>> 8) | 0xc0;
2218 *ansp
++ = offset
& 0xff;
2222 else if (label_type
== 0x80)
2223 return 0; /* reserved */
2224 else if (label_type
== 0x40)
2226 /* Extended label type */
2229 if (!CHECK_LEN(header
, ansp
, plen
, 2))
2232 if (((*ansp
++) & 0x3f) != 1)
2233 return 0; /* we only understand bitstrings */
2235 count
= *(ansp
++); /* Bits in bitstring */
2237 if (count
== 0) /* count == 0 means 256 bits */
2240 ansp
+= ((count
-1)>>3)+1;
2243 { /* label type == 0 Bottom six bits is length */
2244 unsigned int len
= (*ansp
++) & 0x3f;
2246 if (!ADD_RDLEN(header
, ansp
, plen
, len
))
2250 break; /* zero length label marks the end. */
2259 /* Go through RRs and check or fixup the domain names contained within */
2260 static int check_rrs(unsigned char *p
, struct dns_header
*header
, size_t plen
, int fixup
, unsigned char **rrs
, int rr_count
)
2262 int i
, type
, class, rdlen
;
2265 for (i
= 0; i
< ntohs(header
->ancount
) + ntohs(header
->nscount
) + ntohs(header
->arcount
); i
++)
2269 if (!(p
= skip_name(p
, header
, plen
, 10)))
2277 if (type
!= T_NSEC
&& type
!= T_NSEC3
&& type
!= T_RRSIG
)
2279 /* fixup name of RR */
2280 if (!check_name(&pp
, header
, plen
, fixup
, rrs
, rr_count
))
2287 for (pp
= p
, d
= get_desc(type
); *d
!= (u16
)-1; d
++)
2291 else if (!check_name(&pp
, header
, plen
, fixup
, rrs
, rr_count
))
2297 if (!ADD_RDLEN(header
, p
, plen
, rdlen
))
2305 size_t filter_rrsigs(struct dns_header
*header
, size_t plen
)
2307 static unsigned char **rrs
;
2308 static int rr_sz
= 0;
2310 unsigned char *p
= (unsigned char *)(header
+1);
2311 int i
, rdlen
, qtype
, qclass
, rr_found
, chop_an
, chop_ns
, chop_ar
;
2313 if (ntohs(header
->qdcount
) != 1 ||
2314 !(p
= skip_name(p
, header
, plen
, 4)))
2318 GETSHORT(qclass
, p
);
2320 /* First pass, find pointers to start and end of all the records we wish to elide:
2321 records added for DNSSEC, unless explicity queried for */
2322 for (rr_found
= 0, chop_ns
= 0, chop_an
= 0, chop_ar
= 0, i
= 0;
2323 i
< ntohs(header
->ancount
) + ntohs(header
->nscount
) + ntohs(header
->arcount
);
2326 unsigned char *pstart
= p
;
2329 if (!(p
= skip_name(p
, header
, plen
, 10)))
2337 if ((type
== T_NSEC
|| type
== T_NSEC3
|| type
== T_RRSIG
) &&
2338 (type
!= qtype
|| class != qclass
))
2340 if (!expand_workspace(&rrs
, &rr_sz
, rr_found
+ 1))
2343 rrs
[rr_found
++] = pstart
;
2345 if (!ADD_RDLEN(header
, p
, plen
, rdlen
))
2348 rrs
[rr_found
++] = p
;
2350 if (i
< ntohs(header
->ancount
))
2352 else if (i
< (ntohs(header
->nscount
) + ntohs(header
->ancount
)))
2357 else if (!ADD_RDLEN(header
, p
, plen
, rdlen
))
2361 /* Nothing to do. */
2365 /* Second pass, look for pointers in names in the records we're keeping and make sure they don't
2366 point to records we're going to elide. This is theoretically possible, but unlikely. If
2367 it happens, we give up and leave the answer unchanged. */
2368 p
= (unsigned char *)(header
+1);
2370 /* question first */
2371 if (!check_name(&p
, header
, plen
, 0, rrs
, rr_found
))
2373 p
+= 4; /* qclass, qtype */
2375 /* Now answers and NS */
2376 if (!check_rrs(p
, header
, plen
, 0, rrs
, rr_found
))
2379 /* Third pass, elide records */
2380 for (p
= rrs
[0], i
= 1; i
< rr_found
; i
+= 2)
2382 unsigned char *start
= rrs
[i
];
2383 unsigned char *end
= (i
!= rr_found
- 1) ? rrs
[i
+1] : ((unsigned char *)(header
+1)) + plen
;
2385 memmove(p
, start
, end
-start
);
2389 plen
= p
- (unsigned char *)header
;
2390 header
->ancount
= htons(ntohs(header
->ancount
) - chop_an
);
2391 header
->nscount
= htons(ntohs(header
->nscount
) - chop_ns
);
2392 header
->arcount
= htons(ntohs(header
->arcount
) - chop_ar
);
2394 /* Fourth pass, fix up pointers in the remaining records */
2395 p
= (unsigned char *)(header
+1);
2397 check_name(&p
, header
, plen
, 1, rrs
, rr_found
);
2398 p
+= 4; /* qclass, qtype */
2400 check_rrs(p
, header
, plen
, 1, rrs
, rr_found
);
2405 unsigned char* hash_questions(struct dns_header
*header
, size_t plen
, char *name
)
2409 unsigned char *p
= (unsigned char *)(header
+1);
2410 const struct nettle_hash
*hash
;
2412 unsigned char *digest
;
2414 if (!(hash
= hash_find("sha1")) || !hash_init(hash
, &ctx
, &digest
))
2417 for (q
= ntohs(header
->qdcount
); q
!= 0; q
--)
2419 if (!extract_name(header
, plen
, &p
, name
, 1, 4))
2420 break; /* bad packet */
2422 len
= to_wire(name
);
2423 hash
->update(ctx
, len
, (unsigned char *)name
);
2424 /* CRC the class and type as well */
2425 hash
->update(ctx
, 4, p
);
2428 if (!CHECK_LEN(header
, p
, plen
, 0))
2429 break; /* bad packet */
2432 hash
->digest(ctx
, hash
->digest_size
, digest
);
2436 #endif /* HAVE_DNSSEC */