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 Note that both /000 and '.' are allowed within labels. These get
326 represented in presentation format using NAME_ESCAPE as an escape
327 character. In theory, if all the characters in a name were /000 or
328 '.' or NAME_ESCAPE then all would have to be escaped, so the
329 presentation format would be twice as long as the spec (1024).
330 The buffers are all delcared as 2049 (allowing for the trailing zero)
333 static int to_wire(char *name
)
335 unsigned char *l
, *p
, *q
, term
;
338 for (l
= (unsigned char*)name
; *l
!= 0; l
= p
)
340 for (p
= l
; *p
!= '.' && *p
!= 0; p
++)
341 if (*p
>= 'A' && *p
<= 'Z')
343 else if (*p
== NAME_ESCAPE
)
351 if ((len
= p
- l
) != 0)
352 memmove(l
+1, l
, len
);
361 return l
+ 1 - (unsigned char *)name
;
364 /* Note: no compression allowed in input. */
365 static void from_wire(char *name
)
367 unsigned char *l
, *p
, *last
;
370 for (last
= (unsigned char *)name
; *last
!= 0; last
+= *last
+1);
372 for (l
= (unsigned char *)name
; *l
!= 0; l
+= len
+1)
375 memmove(l
, l
+1, len
);
376 for (p
= l
; p
< l
+ len
; p
++)
377 if (*p
== '.' || *p
== 0 || *p
== NAME_ESCAPE
)
379 memmove(p
+1, p
, 1 + last
- p
);
388 if ((char *)l
!= name
)
392 /* Input in presentation format */
393 static int count_labels(char *name
)
400 for (i
= 0; *name
; name
++)
407 /* Implement RFC1982 wrapped compare for 32-bit numbers */
408 static int serial_compare_32(unsigned long s1
, unsigned long s2
)
413 if ((s1
< s2
&& (s2
- s1
) < (1UL<<31)) ||
414 (s1
> s2
&& (s1
- s2
) > (1UL<<31)))
416 if ((s1
< s2
&& (s2
- s1
) > (1UL<<31)) ||
417 (s1
> s2
&& (s1
- s2
) < (1UL<<31)))
422 /* Called at startup. If the timestamp file is configured and exists, put its mtime on
423 timestamp_time. If it doesn't exist, create it, and set the mtime to 1-1-2015.
424 return -1 -> Cannot create file.
425 0 -> not using timestamp, or timestamp exists and is in past.
426 1 -> timestamp exists and is in future.
429 static time_t timestamp_time
;
430 static int back_to_the_future
;
432 int setup_timestamp(void)
436 back_to_the_future
= 0;
438 if (!daemon
->timestamp_file
)
441 if (stat(daemon
->timestamp_file
, &statbuf
) != -1)
443 timestamp_time
= statbuf
.st_mtime
;
445 if (difftime(timestamp_time
, time(0)) <= 0)
447 /* time already OK, update timestamp, and do key checking from the start. */
448 if (utime(daemon
->timestamp_file
, NULL
) == -1)
449 my_syslog(LOG_ERR
, _("failed to update mtime on %s: %s"), daemon
->timestamp_file
, strerror(errno
));
450 back_to_the_future
= 1;
458 /* NB. for explanation of O_EXCL flag, see comment on pidfile in dnsmasq.c */
459 int fd
= open(daemon
->timestamp_file
, O_WRONLY
| O_CREAT
| O_NONBLOCK
| O_EXCL
, 0666);
462 struct utimbuf timbuf
;
466 timestamp_time
= timbuf
.actime
= timbuf
.modtime
= 1420070400; /* 1-1-2015 */
467 if (utime(daemon
->timestamp_file
, &timbuf
) == 0)
475 /* Check whether today/now is between date_start and date_end */
476 static int check_date_range(unsigned long date_start
, unsigned long date_end
)
478 unsigned long curtime
= time(0);
480 /* Checking timestamps may be temporarily disabled */
482 /* If the current time if _before_ the timestamp
483 on our persistent timestamp file, then assume the
484 time if not yet correct, and don't check the
485 key timestamps. As soon as the current time is
486 later then the timestamp, update the timestamp
487 and start checking keys */
488 if (daemon
->timestamp_file
)
490 if (back_to_the_future
== 0 && difftime(timestamp_time
, curtime
) <= 0)
492 if (utime(daemon
->timestamp_file
, NULL
) != 0)
493 my_syslog(LOG_ERR
, _("failed to update mtime on %s: %s"), daemon
->timestamp_file
, strerror(errno
));
495 back_to_the_future
= 1;
496 set_option_bool(OPT_DNSSEC_TIME
);
497 queue_event(EVENT_RELOAD
); /* purge cache */
500 if (back_to_the_future
== 0)
503 else if (option_bool(OPT_DNSSEC_TIME
))
506 /* We must explicitly check against wanted values, because of SERIAL_UNDEF */
507 return serial_compare_32(curtime
, date_start
) == SERIAL_GT
508 && serial_compare_32(curtime
, date_end
) == SERIAL_LT
;
511 static u16
*get_desc(int type
)
513 /* List of RRtypes which include domains in the data.
515 integer -> no of plain bytes
518 zero is not a valid RRtype, so the final entry is returned for
519 anything which needs no mangling.
522 static u16 rr_desc
[] =
544 0, -1 /* wildcard/catchall */
549 while (*p
!= type
&& *p
!= 0)
550 while (*p
++ != (u16
)-1);
555 /* Return bytes of canonicalised rdata, when the return value is zero, the remaining
556 data, pointed to by *p, should be used raw. */
557 static int get_rdata(struct dns_header
*header
, size_t plen
, unsigned char *end
, char *buff
, int bufflen
,
558 unsigned char **p
, u16
**desc
)
562 /* No more data needs mangling */
565 /* If there's more data than we have space for, just return what fits,
566 we'll get called again for more chunks */
567 if (end
- *p
> bufflen
)
569 memcpy(buff
, *p
, bufflen
);
579 if (d
== 0 && extract_name(header
, plen
, p
, buff
, 1, 0))
580 /* domain-name, canonicalise */
581 return to_wire(buff
);
584 /* plain data preceding a domain-name, don't run off the end of the data */
598 static int expand_workspace(unsigned char ***wkspc
, int *sz
, int new)
611 if (!(p
= whine_malloc((new_sz
) * sizeof(unsigned char **))))
616 memcpy(p
, *wkspc
, *sz
* sizeof(unsigned char **));
626 /* Bubble sort the RRset into the canonical order.
627 Note that the byte-streams from two RRs may get unsynced: consider
628 RRs which have two domain-names at the start and then other data.
629 The domain-names may have different lengths in each RR, but sort equal
637 leaving the following bytes as deciding the order. Hence the nasty left1 and left2 variables.
640 static void sort_rrset(struct dns_header
*header
, size_t plen
, u16
*rr_desc
, int rrsetidx
,
641 unsigned char **rrset
, char *buff1
, char *buff2
)
647 for (swap
= 0, i
= 0; i
< rrsetidx
-1; i
++)
649 int rdlen1
, rdlen2
, left1
, left2
, len1
, len2
, len
, rc
;
651 unsigned char *end1
, *end2
;
652 /* Note that these have been determined to be OK previously,
653 so we don't need to check for NULL return here. */
654 unsigned char *p1
= skip_name(rrset
[i
], header
, plen
, 10);
655 unsigned char *p2
= skip_name(rrset
[i
+1], header
, plen
, 10);
657 p1
+= 8; /* skip class, type, ttl */
658 GETSHORT(rdlen1
, p1
);
661 p2
+= 8; /* skip class, type, ttl */
662 GETSHORT(rdlen2
, p2
);
667 for (quit
= 0, left1
= 0, left2
= 0, len1
= 0, len2
= 0; !quit
;)
670 memmove(buff1
, buff1
+ len1
- left1
, left1
);
672 if ((len1
= get_rdata(header
, plen
, end1
, buff1
+ left1
, (MAXDNAME
* 2) - left1
, &p1
, &dp1
)) == 0)
676 memcpy(buff1
+ left1
, p1
, len1
);
681 memmove(buff2
, buff2
+ len2
- left2
, left2
);
683 if ((len2
= get_rdata(header
, plen
, end2
, buff2
+ left2
, (MAXDNAME
*2) - left2
, &p2
, &dp2
)) == 0)
687 memcpy(buff2
+ left2
, p2
, len2
);
692 left1
= len1
- len2
, left2
= 0, len
= len2
;
694 left2
= len2
- len1
, left1
= 0, len
= len1
;
696 rc
= (len
== 0) ? 0 : memcmp(buff1
, buff2
, len
);
698 if (rc
> 0 || (rc
== 0 && quit
&& len1
> len2
))
700 unsigned char *tmp
= rrset
[i
+1];
701 rrset
[i
+1] = rrset
[i
];
712 /* Validate a single RRset (class, type, name) in the supplied DNS reply
714 STAT_SECURE if it validates.
715 STAT_SECURE_WILDCARD if it validates and is the result of wildcard expansion.
716 (In this case *wildcard_out points to the "body" of the wildcard within name.)
717 STAT_NO_SIG no RRsigs found.
718 STAT_INSECURE RRset empty.
719 STAT_BOGUS signature is wrong, bad packet.
720 STAT_NEED_KEY need DNSKEY to complete validation (name is returned in keyname)
722 if key is non-NULL, use that key, which has the algo and tag given in the params of those names,
723 otherwise find the key in the cache.
725 name is unchanged on exit. keyname is used as workspace and trashed.
727 static int validate_rrset(time_t now
, struct dns_header
*header
, size_t plen
, int class, int type
,
728 char *name
, char *keyname
, char **wildcard_out
, struct blockdata
*key
, int keylen
, int algo_in
, int keytag_in
)
730 static unsigned char **rrset
= NULL
, **sigs
= NULL
;
731 static int rrset_sz
= 0, sig_sz
= 0;
734 int rrsetidx
, sigidx
, res
, rdlen
, j
, name_labels
;
735 struct crec
*crecp
= NULL
;
736 int type_covered
, algo
, labels
, orig_ttl
, sig_expiration
, sig_inception
, key_tag
;
737 u16
*rr_desc
= get_desc(type
);
740 *wildcard_out
= NULL
;
742 if (!(p
= skip_questions(header
, plen
)))
745 name_labels
= count_labels(name
); /* For 4035 5.3.2 check */
747 /* look for RRSIGs for this RRset and get pointers to each RR in the set. */
748 for (rrsetidx
= 0, sigidx
= 0, j
= ntohs(header
->ancount
) + ntohs(header
->nscount
);
751 unsigned char *pstart
, *pdata
;
756 if (!(res
= extract_name(header
, plen
, &p
, name
, 0, 10)))
757 return STAT_BOGUS
; /* bad packet */
767 if (!CHECK_LEN(header
, p
, plen
, rdlen
))
770 if (res
== 1 && sclass
== class)
774 if (!expand_workspace(&rrset
, &rrset_sz
, rrsetidx
))
777 rrset
[rrsetidx
++] = pstart
;
780 if (stype
== T_RRSIG
)
783 return STAT_BOGUS
; /* bad packet */
785 GETSHORT(type_covered
, p
);
787 if (type_covered
== type
)
789 if (!expand_workspace(&sigs
, &sig_sz
, sigidx
))
792 sigs
[sigidx
++] = pdata
;
795 p
= pdata
+ 2; /* restore for ADD_RDLEN */
799 if (!ADD_RDLEN(header
, p
, plen
, rdlen
))
805 return STAT_INSECURE
;
811 /* Sort RRset records into canonical order.
812 Note that at this point keyname and daemon->workspacename buffs are
813 unused, and used as workspace by the sort. */
814 sort_rrset(header
, plen
, rr_desc
, rrsetidx
, rrset
, daemon
->workspacename
, keyname
);
816 /* Now try all the sigs to try and find one which validates */
817 for (j
= 0; j
<sigidx
; j
++)
819 unsigned char *psav
, *sig
, *digest
;
820 int i
, wire_len
, sig_len
;
821 const struct nettle_hash
*hash
;
827 GETSHORT(rdlen
, p
); /* rdlen >= 18 checked previously */
830 p
+= 2; /* type_covered - already checked */
833 GETLONG(orig_ttl
, p
);
834 GETLONG(sig_expiration
, p
);
835 GETLONG(sig_inception
, p
);
836 GETSHORT(key_tag
, p
);
838 if (!extract_name(header
, plen
, &p
, keyname
, 1, 0))
841 /* RFC 4035 5.3.1 says that the Signer's Name field MUST equal
842 the name of the zone containing the RRset. We can't tell that
843 for certain, but we can check that the RRset name is equal to
844 or encloses the signers name, which should be enough to stop
845 an attacker using signatures made with the key of an unrelated
846 zone he controls. Note that the root key is always allowed. */
851 for (name_start
= name
; !hostname_isequal(name_start
, keyname
); )
852 if ((name_start
= strchr(name_start
, '.')))
853 name_start
++; /* chop a label off and try again */
860 /* Bad sig, try another */
865 /* Other 5.3.1 checks */
866 if (!check_date_range(sig_inception
, sig_expiration
) ||
867 labels
> name_labels
||
868 !(hash
= hash_find(algo_digest_name(algo
))) ||
869 !hash_init(hash
, &ctx
, &digest
))
872 /* OK, we have the signature record, see if the relevant DNSKEY is in the cache. */
873 if (!key
&& !(crecp
= cache_find_by_name(NULL
, keyname
, now
, F_DNSKEY
)))
874 return STAT_NEED_KEY
;
877 sig_len
= rdlen
- (p
- psav
);
879 nsigttl
= htonl(orig_ttl
);
881 hash
->update(ctx
, 18, psav
);
882 wire_len
= to_wire(keyname
);
883 hash
->update(ctx
, (unsigned int)wire_len
, (unsigned char*)keyname
);
886 for (i
= 0; i
< rrsetidx
; ++i
)
889 unsigned char *end
, *cp
;
893 if (!extract_name(header
, plen
, &p
, name
, 1, 10))
898 /* if more labels than in RRsig name, hash *.<no labels in rrsig labels field> 4035 5.3.2 */
899 if (labels
< name_labels
)
902 for (k
= name_labels
- labels
; k
!= 0; k
--)
904 while (*name_start
!= '.' && *name_start
!= 0)
906 if (k
!= 1 && *name_start
== '.')
911 *wildcard_out
= name_start
+1;
917 wire_len
= to_wire(name_start
);
918 hash
->update(ctx
, (unsigned int)wire_len
, (unsigned char *)name_start
);
919 hash
->update(ctx
, 4, p
); /* class and type */
920 hash
->update(ctx
, 4, (unsigned char *)&nsigttl
);
922 p
+= 8; /* skip class, type, ttl */
924 if (!CHECK_LEN(header
, p
, plen
, rdlen
))
929 /* canonicalise rdata and calculate length of same, use name buffer as workspace.
930 Note that name buffer is twice MAXDNAME long in DNSSEC mode. */
933 for (len
= 0; (seg
= get_rdata(header
, plen
, end
, name
, MAXDNAME
* 2, &cp
, &dp
)) != 0; len
+= seg
);
936 hash
->update(ctx
, 2, (unsigned char *)&len
);
938 /* Now canonicalise again and digest. */
941 while ((seg
= get_rdata(header
, plen
, end
, name
, MAXDNAME
* 2, &cp
, &dp
)))
942 hash
->update(ctx
, seg
, (unsigned char *)name
);
944 hash
->update(ctx
, end
- cp
, cp
);
947 hash
->digest(ctx
, hash
->digest_size
, digest
);
949 /* namebuff used for workspace above, restore to leave unchanged on exit */
950 p
= (unsigned char*)(rrset
[0]);
951 extract_name(header
, plen
, &p
, name
, 1, 0);
955 if (algo_in
== algo
&& keytag_in
== key_tag
&&
956 verify(key
, keylen
, sig
, sig_len
, digest
, hash
->digest_size
, algo
))
961 /* iterate through all possible keys 4035 5.3.1 */
962 for (; crecp
; crecp
= cache_find_by_name(crecp
, keyname
, now
, F_DNSKEY
))
963 if (crecp
->addr
.key
.algo
== algo
&&
964 crecp
->addr
.key
.keytag
== key_tag
&&
965 crecp
->uid
== (unsigned int)class &&
966 verify(crecp
->addr
.key
.keydata
, crecp
->addr
.key
.keylen
, sig
, sig_len
, digest
, hash
->digest_size
, algo
))
967 return (labels
< name_labels
) ? STAT_SECURE_WILDCARD
: STAT_SECURE
;
974 /* The DNS packet is expected to contain the answer to a DNSKEY query.
975 Put all DNSKEYs in the answer which are valid into the cache.
977 STAT_SECURE At least one valid DNSKEY found and in cache.
978 STAT_BOGUS No DNSKEYs found, which can be validated with DS,
979 or self-sign for DNSKEY RRset is not valid, bad packet.
980 STAT_NEED_DS DS records to validate a key not found, name in keyname
982 int dnssec_validate_by_ds(time_t now
, struct dns_header
*header
, size_t plen
, char *name
, char *keyname
, int class)
984 unsigned char *psave
, *p
= (unsigned char *)(header
+1);
985 struct crec
*crecp
, *recp1
;
986 int rc
, j
, qtype
, qclass
, ttl
, rdlen
, flags
, algo
, valid
, keytag
, type_covered
;
987 struct blockdata
*key
;
990 if (ntohs(header
->qdcount
) != 1 ||
991 !extract_name(header
, plen
, &p
, name
, 1, 4))
997 if (qtype
!= T_DNSKEY
|| qclass
!= class || ntohs(header
->ancount
) == 0)
1000 /* See if we have cached a DS record which validates this key */
1001 if (!(crecp
= cache_find_by_name(NULL
, name
, now
, F_DS
)))
1003 strcpy(keyname
, name
);
1004 return STAT_NEED_DS
;
1007 /* If we've cached that DS provably doesn't exist, result must be INSECURE */
1008 if (crecp
->flags
& F_NEG
)
1009 return STAT_INSECURE_DS
;
1011 /* NOTE, we need to find ONE DNSKEY which matches the DS */
1012 for (valid
= 0, j
= ntohs(header
->ancount
); j
!= 0 && !valid
; j
--)
1014 /* Ensure we have type, class TTL and length */
1015 if (!(rc
= extract_name(header
, plen
, &p
, name
, 0, 10)))
1016 return STAT_BOGUS
; /* bad packet */
1019 GETSHORT(qclass
, p
);
1023 if (!CHECK_LEN(header
, p
, plen
, rdlen
) || rdlen
< 4)
1024 return STAT_BOGUS
; /* bad packet */
1026 if (qclass
!= class || qtype
!= T_DNSKEY
|| rc
== 2)
1038 keytag
= dnskey_keytag(algo
, flags
, p
, rdlen
- 4);
1041 /* key must have zone key flag set */
1043 key
= blockdata_alloc((char*)p
, rdlen
- 4);
1047 if (!ADD_RDLEN(header
, p
, plen
, rdlen
))
1050 blockdata_free(key
);
1051 return STAT_BOGUS
; /* bad packet */
1054 /* No zone key flag or malloc failure */
1058 for (recp1
= crecp
; recp1
; recp1
= cache_find_by_name(recp1
, name
, now
, F_DS
))
1061 unsigned char *digest
, *ds_digest
;
1062 const struct nettle_hash
*hash
;
1064 if (recp1
->addr
.ds
.algo
== algo
&&
1065 recp1
->addr
.ds
.keytag
== keytag
&&
1066 recp1
->uid
== (unsigned int)class &&
1067 (hash
= hash_find(ds_digest_name(recp1
->addr
.ds
.digest
))) &&
1068 hash_init(hash
, &ctx
, &digest
))
1071 int wire_len
= to_wire(name
);
1073 /* Note that digest may be different between DSs, so
1074 we can't move this outside the loop. */
1075 hash
->update(ctx
, (unsigned int)wire_len
, (unsigned char *)name
);
1076 hash
->update(ctx
, (unsigned int)rdlen
, psave
);
1077 hash
->digest(ctx
, hash
->digest_size
, digest
);
1081 if (recp1
->addr
.ds
.keylen
== (int)hash
->digest_size
&&
1082 (ds_digest
= blockdata_retrieve(recp1
->addr
.key
.keydata
, recp1
->addr
.ds
.keylen
, NULL
)) &&
1083 memcmp(ds_digest
, digest
, recp1
->addr
.ds
.keylen
) == 0 &&
1084 validate_rrset(now
, header
, plen
, class, T_DNSKEY
, name
, keyname
, NULL
, key
, rdlen
- 4, algo
, keytag
) == STAT_SECURE
)
1091 blockdata_free(key
);
1096 /* DNSKEY RRset determined to be OK, now cache it and the RRsigs that sign it. */
1097 cache_start_insert();
1099 p
= skip_questions(header
, plen
);
1101 for (j
= ntohs(header
->ancount
); j
!= 0; j
--)
1103 /* Ensure we have type, class TTL and length */
1104 if (!(rc
= extract_name(header
, plen
, &p
, name
, 0, 10)))
1105 return STAT_INSECURE
; /* bad packet */
1108 GETSHORT(qclass
, p
);
1112 if (!CHECK_LEN(header
, p
, plen
, rdlen
))
1113 return STAT_BOGUS
; /* bad packet */
1115 if (qclass
== class && rc
== 1)
1119 if (qtype
== T_DNSKEY
)
1122 return STAT_BOGUS
; /* bad packet */
1128 keytag
= dnskey_keytag(algo
, flags
, p
, rdlen
- 4);
1130 /* Cache needs to known class for DNSSEC stuff */
1131 a
.addr
.dnssec
.class = class;
1133 if ((key
= blockdata_alloc((char*)p
, rdlen
- 4)))
1135 if (!(recp1
= cache_insert(name
, &a
, now
, ttl
, F_FORWARD
| F_DNSKEY
| F_DNSSECOK
)))
1136 blockdata_free(key
);
1139 a
.addr
.keytag
= keytag
;
1140 log_query(F_NOEXTRA
| F_KEYTAG
| F_UPSTREAM
, name
, &a
, "DNSKEY keytag %u");
1142 recp1
->addr
.key
.keylen
= rdlen
- 4;
1143 recp1
->addr
.key
.keydata
= key
;
1144 recp1
->addr
.key
.algo
= algo
;
1145 recp1
->addr
.key
.keytag
= keytag
;
1146 recp1
->addr
.key
.flags
= flags
;
1150 else if (qtype
== T_RRSIG
)
1152 /* RRSIG, cache if covers DNSKEY RRset */
1154 return STAT_BOGUS
; /* bad packet */
1156 GETSHORT(type_covered
, p
);
1158 if (type_covered
== T_DNSKEY
)
1160 a
.addr
.dnssec
.class = class;
1161 a
.addr
.dnssec
.type
= type_covered
;
1164 p
+= 13; /* labels, orig_ttl, expiration, inception */
1165 GETSHORT(keytag
, p
);
1166 if ((key
= blockdata_alloc((char*)psave
, rdlen
)))
1168 if (!(crecp
= cache_insert(name
, &a
, now
, ttl
, F_FORWARD
| F_DNSKEY
| F_DS
)))
1169 blockdata_free(key
);
1172 crecp
->addr
.sig
.keydata
= key
;
1173 crecp
->addr
.sig
.keylen
= rdlen
;
1174 crecp
->addr
.sig
.keytag
= keytag
;
1175 crecp
->addr
.sig
.type_covered
= type_covered
;
1176 crecp
->addr
.sig
.algo
= algo
;
1185 if (!ADD_RDLEN(header
, p
, plen
, rdlen
))
1186 return STAT_BOGUS
; /* bad packet */
1189 /* commit cache insert. */
1194 log_query(F_NOEXTRA
| F_UPSTREAM
, name
, NULL
, "BOGUS DNSKEY");
1198 /* The DNS packet is expected to contain the answer to a DS query
1199 Put all DSs in the answer which are valid into the cache.
1201 STAT_SECURE At least one valid DS found and in cache.
1202 STAT_NO_DS It's proved there's no DS here.
1203 STAT_NO_NS It's proved there's no DS _or_ NS here.
1204 STAT_BOGUS no DS in reply or not signed, fails validation, bad packet.
1205 STAT_NEED_KEY DNSKEY records to validate a DS not found, name in keyname
1208 int dnssec_validate_ds(time_t now
, struct dns_header
*header
, size_t plen
, char *name
, char *keyname
, int class)
1210 unsigned char *p
= (unsigned char *)(header
+1);
1211 int qtype
, qclass
, val
, i
, neganswer
, nons
;
1213 if (ntohs(header
->qdcount
) != 1 ||
1214 !(p
= skip_name(p
, header
, plen
, 4)))
1218 GETSHORT(qclass
, p
);
1220 if (qtype
!= T_DS
|| qclass
!= class)
1223 val
= dnssec_validate_reply(now
, header
, plen
, name
, keyname
, NULL
, &neganswer
, &nons
);
1224 /* Note dnssec_validate_reply() will have cached positive answers */
1226 if (val
== STAT_INSECURE
)
1229 if (val
== STAT_NO_SIG
)
1232 p
= (unsigned char *)(header
+1);
1233 extract_name(header
, plen
, &p
, name
, 1, 4);
1234 p
+= 4; /* qtype, qclass */
1236 if (!(p
= skip_section(p
, ntohs(header
->ancount
), header
, plen
)))
1239 /* If the key needed to validate the DS is on the same domain as the DS, we'll
1240 loop getting nowhere. Stop that now. This can happen of the DS answer comes
1241 from the DS's zone, and not the parent zone. */
1242 if (val
== STAT_BOGUS
|| (val
== STAT_NEED_KEY
&& hostname_isequal(name
, keyname
)))
1244 log_query(F_NOEXTRA
| F_UPSTREAM
, name
, NULL
, "BOGUS DS");
1248 /* By here, the answer is proved secure, and a positive answer has been cached. */
1249 if (val
== STAT_SECURE
&& neganswer
)
1251 int rdlen
, flags
= F_FORWARD
| F_DS
| F_NEG
| F_DNSSECOK
;
1252 unsigned long ttl
, minttl
= ULONG_MAX
;
1255 if (RCODE(header
) == NXDOMAIN
)
1256 flags
|= F_NXDOMAIN
;
1258 /* We only cache validated DS records, DNSSECOK flag hijacked
1259 to store presence/absence of NS. */
1261 flags
&= ~F_DNSSECOK
;
1263 for (i
= ntohs(header
->nscount
); i
!= 0; i
--)
1265 if (!(p
= skip_name(p
, header
, plen
, 0)))
1269 GETSHORT(qclass
, p
);
1273 if (!CHECK_LEN(header
, p
, plen
, rdlen
))
1274 return STAT_BOGUS
; /* bad packet */
1276 if (qclass
!= class || qtype
!= T_SOA
)
1286 if (!(p
= skip_name(p
, header
, plen
, 0)))
1289 if (!(p
= skip_name(p
, header
, plen
, 20)))
1291 p
+= 16; /* SERIAL REFRESH RETRY EXPIRE */
1293 GETLONG(ttl
, p
); /* minTTL */
1302 cache_start_insert();
1304 a
.addr
.dnssec
.class = class;
1305 cache_insert(name
, &a
, now
, ttl
, flags
);
1309 log_query(F_NOEXTRA
| F_UPSTREAM
, name
, NULL
, nons
? "no delegation" : "no DS");
1312 return nons
? STAT_NO_NS
: STAT_NO_DS
;
1319 static int hostname_cmp(const char *a
, const char *b
)
1321 char *sa
, *ea
, *ca
, *sb
, *eb
, *cb
;
1322 unsigned char ac
, bc
;
1324 sa
= ea
= (char *)a
+ strlen(a
);
1325 sb
= eb
= (char *)b
+ strlen(b
);
1329 while (sa
!= a
&& *(sa
-1) != '.')
1332 while (sb
!= b
&& *(sb
-1) != '.')
1351 ac
= (unsigned char) *ca
++;
1352 bc
= (unsigned char) *cb
++;
1354 if (ac
>= 'A' && ac
<= 'Z')
1356 if (bc
>= 'A' && bc
<= 'Z')
1382 /* Find all the NSEC or NSEC3 records in a reply.
1383 return an array of pointers to them. */
1384 static int find_nsec_records(struct dns_header
*header
, size_t plen
, unsigned char ***nsecsetp
, int *nsecsetl
, int class_reqd
)
1386 static unsigned char **nsecset
= NULL
;
1387 static int nsecset_sz
= 0;
1390 unsigned char *p
= skip_questions(header
, plen
);
1391 int type
, class, rdlen
, i
, nsecs_found
;
1393 /* Move to NS section */
1394 if (!p
|| !(p
= skip_section(p
, ntohs(header
->ancount
), header
, plen
)))
1397 for (nsecs_found
= 0, i
= ntohs(header
->nscount
); i
!= 0; i
--)
1399 unsigned char *pstart
= p
;
1401 if (!(p
= skip_name(p
, header
, plen
, 10)))
1409 if (class == class_reqd
&& (type
== T_NSEC
|| type
== T_NSEC3
))
1411 /* No mixed NSECing 'round here, thankyouverymuch */
1412 if (type_found
== T_NSEC
&& type
== T_NSEC3
)
1414 if (type_found
== T_NSEC3
&& type
== T_NSEC
)
1419 if (!expand_workspace(&nsecset
, &nsecset_sz
, nsecs_found
))
1422 nsecset
[nsecs_found
++] = pstart
;
1425 if (!ADD_RDLEN(header
, p
, plen
, rdlen
))
1429 *nsecsetp
= nsecset
;
1430 *nsecsetl
= nsecs_found
;
1435 static int prove_non_existence_nsec(struct dns_header
*header
, size_t plen
, unsigned char **nsecs
, int nsec_count
,
1436 char *workspace1
, char *workspace2
, char *name
, int type
, int *nons
)
1439 unsigned char *p
, *psave
;
1440 int offset
= (type
& 0xff) >> 3;
1441 int mask
= 0x80 >> (type
& 0x07);
1446 /* Find NSEC record that proves name doesn't exist */
1447 for (i
= 0; i
< nsec_count
; i
++)
1450 if (!extract_name(header
, plen
, &p
, workspace1
, 1, 10))
1452 p
+= 8; /* class, type, TTL */
1455 if (!extract_name(header
, plen
, &p
, workspace2
, 1, 10))
1458 rc
= hostname_cmp(workspace1
, name
);
1462 /* 4035 para 5.4. Last sentence */
1463 if (type
== T_NSEC
|| type
== T_RRSIG
)
1466 /* NSEC with the same name as the RR we're testing, check
1467 that the type in question doesn't appear in the type map */
1469 /* rdlen is now length of type map, and p points to it */
1471 /* If we can prove that there's no NS record, return that information. */
1472 if (nons
&& rdlen
>= 2 && p
[0] == 0 && (p
[2] & (0x80 >> T_NS
)) == 0)
1477 if (!CHECK_LEN(header
, p
, plen
, rdlen
))
1480 if (p
[0] == type
>> 8)
1482 /* Does the NSEC say our type exists? */
1483 if (offset
< p
[1] && (p
[offset
+2] & mask
) != 0)
1486 break; /* finshed checking */
1497 /* Normal case, name falls between NSEC name and next domain name,
1498 wrap around case, name falls between NSEC name (rc == -1) and end */
1499 if (hostname_cmp(workspace2
, name
) >= 0 || hostname_cmp(workspace1
, workspace2
) >= 0)
1504 /* wrap around case, name falls between start and next domain name */
1505 if (hostname_cmp(workspace1
, workspace2
) >= 0 && hostname_cmp(workspace2
, name
) >=0 )
1513 /* return digest length, or zero on error */
1514 static int hash_name(char *in
, unsigned char **out
, struct nettle_hash
const *hash
,
1515 unsigned char *salt
, int salt_len
, int iterations
)
1518 unsigned char *digest
;
1521 if (!hash_init(hash
, &ctx
, &digest
))
1524 hash
->update(ctx
, to_wire(in
), (unsigned char *)in
);
1525 hash
->update(ctx
, salt_len
, salt
);
1526 hash
->digest(ctx
, hash
->digest_size
, digest
);
1528 for(i
= 0; i
< iterations
; i
++)
1530 hash
->update(ctx
, hash
->digest_size
, digest
);
1531 hash
->update(ctx
, salt_len
, salt
);
1532 hash
->digest(ctx
, hash
->digest_size
, digest
);
1538 return hash
->digest_size
;
1541 /* Decode base32 to first "." or end of string */
1542 static int base32_decode(char *in
, unsigned char *out
)
1544 int oc
, on
, c
, mask
, i
;
1545 unsigned char *p
= out
;
1547 for (c
= *in
, oc
= 0, on
= 0; c
!= 0 && c
!= '.'; c
= *++in
)
1549 if (c
>= '0' && c
<= '9')
1551 else if (c
>= 'a' && c
<= 'v')
1553 else if (c
>= 'A' && c
<= 'V')
1558 for (mask
= 0x10, i
= 0; i
< 5; i
++)
1563 if (((++on
) & 7) == 0)
1575 static int check_nsec3_coverage(struct dns_header
*header
, size_t plen
, int digest_len
, unsigned char *digest
, int type
,
1576 char *workspace1
, char *workspace2
, unsigned char **nsecs
, int nsec_count
, int *nons
)
1578 int i
, hash_len
, salt_len
, base32_len
, rdlen
;
1579 unsigned char *p
, *psave
;
1581 for (i
= 0; i
< nsec_count
; i
++)
1584 if (!extract_name(header
, plen
, &p
, workspace1
, 1, 0) ||
1585 !(base32_len
= base32_decode(workspace1
, (unsigned char *)workspace2
)))
1588 p
+= 8; /* class, type, TTL */
1591 p
+= 4; /* algo, flags, iterations */
1592 salt_len
= *p
++; /* salt_len */
1593 p
+= salt_len
; /* salt */
1594 hash_len
= *p
++; /* p now points to next hashed name */
1596 if (!CHECK_LEN(header
, p
, plen
, hash_len
))
1599 if (digest_len
== base32_len
&& hash_len
== base32_len
)
1601 int rc
= memcmp(workspace2
, digest
, digest_len
);
1605 /* We found an NSEC3 whose hashed name exactly matches the query, so
1606 we just need to check the type map. p points to the RR data for the record. */
1608 int offset
= (type
& 0xff) >> 3;
1609 int mask
= 0x80 >> (type
& 0x07);
1611 p
+= hash_len
; /* skip next-domain hash */
1614 if (!CHECK_LEN(header
, p
, plen
, rdlen
))
1617 /* If we can prove that there's no NS record, return that information. */
1618 if (nons
&& rdlen
>= 2 && p
[0] == 0 && (p
[2] & (0x80 >> T_NS
)) == 0)
1623 if (p
[0] == type
>> 8)
1625 /* Does the NSEC3 say our type exists? */
1626 if (offset
< p
[1] && (p
[offset
+2] & mask
) != 0)
1629 break; /* finshed checking */
1640 /* Normal case, hash falls between NSEC3 name-hash and next domain name-hash,
1641 wrap around case, name-hash falls between NSEC3 name-hash and end */
1642 if (memcmp(p
, digest
, digest_len
) >= 0 || memcmp(workspace2
, p
, digest_len
) >= 0)
1647 /* wrap around case, name falls between start and next domain name */
1648 if (memcmp(workspace2
, p
, digest_len
) >= 0 && memcmp(p
, digest
, digest_len
) >= 0)
1656 static int prove_non_existence_nsec3(struct dns_header
*header
, size_t plen
, unsigned char **nsecs
, int nsec_count
,
1657 char *workspace1
, char *workspace2
, char *name
, int type
, char *wildname
, int *nons
)
1659 unsigned char *salt
, *p
, *digest
;
1660 int digest_len
, i
, iterations
, salt_len
, base32_len
, algo
= 0;
1661 struct nettle_hash
const *hash
;
1662 char *closest_encloser
, *next_closest
, *wildcard
;
1667 /* Look though the NSEC3 records to find the first one with
1668 an algorithm we support (currently only algo == 1).
1670 Take the algo, iterations, and salt of that record
1671 as the ones we're going to use, and prune any
1672 that don't match. */
1674 for (i
= 0; i
< nsec_count
; i
++)
1676 if (!(p
= skip_name(nsecs
[i
], header
, plen
, 15)))
1677 return STAT_BOGUS
; /* bad packet */
1679 p
+= 10; /* type, class, TTL, rdlen */
1683 break; /* known algo */
1686 /* No usable NSEC3s */
1687 if (i
== nsec_count
)
1691 GETSHORT (iterations
, p
);
1694 if (!CHECK_LEN(header
, salt
, plen
, salt_len
))
1695 return STAT_BOGUS
; /* bad packet */
1697 /* Now prune so we only have NSEC3 records with same iterations, salt and algo */
1698 for (i
= 0; i
< nsec_count
; i
++)
1700 unsigned char *nsec3p
= nsecs
[i
];
1703 nsecs
[i
] = NULL
; /* Speculative, will be restored if OK. */
1705 if (!(p
= skip_name(nsec3p
, header
, plen
, 15)))
1706 return STAT_BOGUS
; /* bad packet */
1708 p
+= 10; /* type, class, TTL, rdlen */
1715 GETSHORT(this_iter
, p
);
1716 if (this_iter
!= iterations
)
1719 if (salt_len
!= *p
++)
1722 if (!CHECK_LEN(header
, p
, plen
, salt_len
))
1723 return STAT_BOGUS
; /* bad packet */
1725 if (memcmp(p
, salt
, salt_len
) != 0)
1728 /* All match, put the pointer back */
1732 /* Algo is checked as 1 above */
1733 if (!(hash
= hash_find("sha1")))
1736 if ((digest_len
= hash_name(name
, &digest
, hash
, salt
, salt_len
, iterations
)) == 0)
1739 if (check_nsec3_coverage(header
, plen
, digest_len
, digest
, type
, workspace1
, workspace2
, nsecs
, nsec_count
, nons
))
1742 /* Can't find an NSEC3 which covers the name directly, we need the "closest encloser NSEC3"
1743 or an answer inferred from a wildcard record. */
1744 closest_encloser
= name
;
1745 next_closest
= NULL
;
1749 if (*closest_encloser
== '.')
1752 if (wildname
&& hostname_isequal(closest_encloser
, wildname
))
1755 if ((digest_len
= hash_name(closest_encloser
, &digest
, hash
, salt
, salt_len
, iterations
)) == 0)
1758 for (i
= 0; i
< nsec_count
; i
++)
1761 if (!extract_name(header
, plen
, &p
, workspace1
, 1, 0) ||
1762 !(base32_len
= base32_decode(workspace1
, (unsigned char *)workspace2
)))
1765 if (digest_len
== base32_len
&&
1766 memcmp(digest
, workspace2
, digest_len
) == 0)
1770 if (i
!= nsec_count
)
1773 next_closest
= closest_encloser
;
1775 while ((closest_encloser
= strchr(closest_encloser
, '.')));
1777 if (!closest_encloser
)
1780 /* Look for NSEC3 that proves the non-existence of the next-closest encloser */
1781 if ((digest_len
= hash_name(next_closest
, &digest
, hash
, salt
, salt_len
, iterations
)) == 0)
1784 if (!check_nsec3_coverage(header
, plen
, digest_len
, digest
, type
, workspace1
, workspace2
, nsecs
, nsec_count
, NULL
))
1787 /* Finally, check that there's no seat of wildcard synthesis */
1790 if (!(wildcard
= strchr(next_closest
, '.')) || wildcard
== next_closest
)
1796 if ((digest_len
= hash_name(wildcard
, &digest
, hash
, salt
, salt_len
, iterations
)) == 0)
1799 if (!check_nsec3_coverage(header
, plen
, digest_len
, digest
, type
, workspace1
, workspace2
, nsecs
, nsec_count
, NULL
))
1806 /* Validate all the RRsets in the answer and authority sections of the reply (4035:3.2.3) */
1807 /* Returns are the same as validate_rrset, plus the class if the missing key is in *class */
1808 int dnssec_validate_reply(time_t now
, struct dns_header
*header
, size_t plen
, char *name
, char *keyname
,
1809 int *class, int *neganswer
, int *nons
)
1811 unsigned char *ans_start
, *qname
, *p1
, *p2
, **nsecs
;
1812 int type1
, class1
, rdlen1
, type2
, class2
, rdlen2
, qclass
, qtype
;
1813 int i
, j
, rc
, nsec_count
, cname_count
= CNAME_CHAIN
;
1814 int nsec_type
= 0, have_answer
= 0;
1819 if (RCODE(header
) == SERVFAIL
|| ntohs(header
->qdcount
) != 1)
1822 if (RCODE(header
) != NXDOMAIN
&& RCODE(header
) != NOERROR
)
1823 return STAT_INSECURE
;
1825 qname
= p1
= (unsigned char *)(header
+1);
1827 if (!extract_name(header
, plen
, &p1
, name
, 1, 4))
1830 GETSHORT(qtype
, p1
);
1831 GETSHORT(qclass
, p1
);
1837 /* Can't validate an RRISG query */
1838 if (qtype
== T_RRSIG
)
1839 return STAT_INSECURE
;
1842 for (j
= ntohs(header
->ancount
); j
!= 0; j
--)
1844 /* leave pointer to missing name in qname */
1846 if (!(rc
= extract_name(header
, plen
, &p1
, name
, 0, 10)))
1847 return STAT_BOGUS
; /* bad packet */
1849 GETSHORT(type2
, p1
);
1850 GETSHORT(class2
, p1
);
1852 GETSHORT(rdlen2
, p1
);
1854 if (rc
== 1 && qclass
== class2
)
1856 /* Do we have an answer for the question? */
1862 else if (type2
== T_CNAME
)
1867 if (!cname_count
-- || !extract_name(header
, plen
, &p1
, name
, 1, 0))
1875 if (!ADD_RDLEN(header
, p1
, plen
, rdlen2
))
1879 if (neganswer
&& !have_answer
)
1882 /* No data, therefore no sigs */
1883 if (ntohs(header
->ancount
) + ntohs(header
->nscount
) == 0)
1889 for (p1
= ans_start
, i
= 0; i
< ntohs(header
->ancount
) + ntohs(header
->nscount
); i
++)
1891 if (!extract_name(header
, plen
, &p1
, name
, 1, 10))
1892 return STAT_BOGUS
; /* bad packet */
1894 GETSHORT(type1
, p1
);
1895 GETSHORT(class1
, p1
);
1897 GETSHORT(rdlen1
, p1
);
1899 /* Don't try and validate RRSIGs! */
1900 if (type1
!= T_RRSIG
)
1902 /* Check if we've done this RRset already */
1903 for (p2
= ans_start
, j
= 0; j
< i
; j
++)
1905 if (!(rc
= extract_name(header
, plen
, &p2
, name
, 0, 10)))
1906 return STAT_BOGUS
; /* bad packet */
1908 GETSHORT(type2
, p2
);
1909 GETSHORT(class2
, p2
);
1911 GETSHORT(rdlen2
, p2
);
1913 if (type2
== type1
&& class2
== class1
&& rc
== 1)
1914 break; /* Done it before: name, type, class all match. */
1916 if (!ADD_RDLEN(header
, p2
, plen
, rdlen2
))
1920 /* Not done, validate now */
1923 int ttl
, keytag
, algo
, digest
, type_covered
;
1924 unsigned char *psave
;
1926 struct blockdata
*key
;
1929 int have_wildcard
= 0;
1931 rc
= validate_rrset(now
, header
, plen
, class1
, type1
, name
, keyname
, &wildname
, NULL
, 0, 0, 0);
1933 if (rc
== STAT_SECURE_WILDCARD
)
1937 /* An attacker replay a wildcard answer with a different
1938 answer and overlay a genuine RR. To prove this
1939 hasn't happened, the answer must prove that
1940 the gennuine record doesn't exist. Check that here. */
1941 if (!nsec_type
&& !(nsec_type
= find_nsec_records(header
, plen
, &nsecs
, &nsec_count
, class1
)))
1942 return STAT_BOGUS
; /* No NSECs or bad packet */
1944 if (nsec_type
== T_NSEC
)
1945 rc
= prove_non_existence_nsec(header
, plen
, nsecs
, nsec_count
, daemon
->workspacename
, keyname
, name
, type1
, NULL
);
1947 rc
= prove_non_existence_nsec3(header
, plen
, nsecs
, nsec_count
, daemon
->workspacename
,
1948 keyname
, name
, type1
, wildname
, NULL
);
1950 if (rc
!= STAT_SECURE
)
1953 else if (rc
!= STAT_SECURE
)
1956 *class = class1
; /* Class for DS or DNSKEY */
1958 if (rc
== STAT_NO_SIG
)
1960 /* If we dropped off the end of a CNAME chain, return
1961 STAT_NO_SIG and the last name is keyname. This is used for proving non-existence
1962 if DS records in CNAME chains. */
1963 if (cname_count
== CNAME_CHAIN
|| i
< ntohs(header
->ancount
))
1964 /* No CNAME chain, or no sig in answer section, return empty name. */
1966 else if (!extract_name(header
, plen
, &qname
, keyname
, 1, 0))
1973 /* Cache RRsigs in answer section, and if we just validated a DS RRset, cache it */
1974 cache_start_insert();
1976 for (p2
= ans_start
, j
= 0; j
< ntohs(header
->ancount
); j
++)
1978 if (!(rc
= extract_name(header
, plen
, &p2
, name
, 0, 10)))
1979 return STAT_BOGUS
; /* bad packet */
1981 GETSHORT(type2
, p2
);
1982 GETSHORT(class2
, p2
);
1984 GETSHORT(rdlen2
, p2
);
1986 if (!CHECK_LEN(header
, p2
, plen
, rdlen2
))
1987 return STAT_BOGUS
; /* bad packet */
1989 if (class2
== class1
&& rc
== 1)
1993 if (type1
== T_DS
&& type2
== T_DS
)
1996 return STAT_BOGUS
; /* bad packet */
1998 GETSHORT(keytag
, p2
);
2002 /* Cache needs to known class for DNSSEC stuff */
2003 a
.addr
.dnssec
.class = class2
;
2005 if ((key
= blockdata_alloc((char*)p2
, rdlen2
- 4)))
2007 if (!(crecp
= cache_insert(name
, &a
, now
, ttl
, F_FORWARD
| F_DS
| F_DNSSECOK
)))
2008 blockdata_free(key
);
2011 a
.addr
.keytag
= keytag
;
2012 log_query(F_NOEXTRA
| F_KEYTAG
| F_UPSTREAM
, name
, &a
, "DS keytag %u");
2013 crecp
->addr
.ds
.digest
= digest
;
2014 crecp
->addr
.ds
.keydata
= key
;
2015 crecp
->addr
.ds
.algo
= algo
;
2016 crecp
->addr
.ds
.keytag
= keytag
;
2017 crecp
->addr
.ds
.keylen
= rdlen2
- 4;
2021 else if (type2
== T_RRSIG
)
2024 return STAT_BOGUS
; /* bad packet */
2026 GETSHORT(type_covered
, p2
);
2028 if (type_covered
== type1
&&
2029 (type_covered
== T_A
|| type_covered
== T_AAAA
||
2030 type_covered
== T_CNAME
|| type_covered
== T_DS
||
2031 type_covered
== T_DNSKEY
|| type_covered
== T_PTR
))
2033 a
.addr
.dnssec
.type
= type_covered
;
2034 a
.addr
.dnssec
.class = class1
;
2037 p2
+= 13; /* labels, orig_ttl, expiration, inception */
2038 GETSHORT(keytag
, p2
);
2040 /* We don't cache sigs for wildcard answers, because to reproduce the
2041 answer from the cache will require one or more NSEC/NSEC3 records
2042 which we don't cache. The lack of the RRSIG ensures that a query for
2043 this RRset asking for a secure answer will always be forwarded. */
2044 if (!have_wildcard
&& (key
= blockdata_alloc((char*)psave
, rdlen2
)))
2046 if (!(crecp
= cache_insert(name
, &a
, now
, ttl
, F_FORWARD
| F_DNSKEY
| F_DS
)))
2047 blockdata_free(key
);
2050 crecp
->addr
.sig
.keydata
= key
;
2051 crecp
->addr
.sig
.keylen
= rdlen2
;
2052 crecp
->addr
.sig
.keytag
= keytag
;
2053 crecp
->addr
.sig
.type_covered
= type_covered
;
2054 crecp
->addr
.sig
.algo
= algo
;
2063 if (!ADD_RDLEN(header
, p2
, plen
, rdlen2
))
2064 return STAT_BOGUS
; /* bad packet */
2071 if (!ADD_RDLEN(header
, p1
, plen
, rdlen1
))
2075 /* OK, all the RRsets validate, now see if we have a NODATA or NXDOMAIN reply */
2079 /* NXDOMAIN or NODATA reply, prove that (name, class1, type1) can't exist */
2080 /* First marshall the NSEC records, if we've not done it previously */
2081 if (!nsec_type
&& !(nsec_type
= find_nsec_records(header
, plen
, &nsecs
, &nsec_count
, qclass
)))
2083 /* No NSEC records. If we dropped off the end of a CNAME chain, return
2084 STAT_NO_SIG and the last name is keyname. This is used for proving non-existence
2085 if DS records in CNAME chains. */
2086 if (cname_count
== CNAME_CHAIN
) /* No CNAME chain, return empty name. */
2088 else if (!extract_name(header
, plen
, &qname
, keyname
, 1, 0))
2090 return STAT_NO_SIG
; /* No NSECs, this is probably a dangling CNAME pointing into
2091 an unsigned zone. Return STAT_NO_SIG to cause this to be proved. */
2094 /* Get name of missing answer */
2095 if (!extract_name(header
, plen
, &qname
, name
, 1, 0))
2098 if (nsec_type
== T_NSEC
)
2099 return prove_non_existence_nsec(header
, plen
, nsecs
, nsec_count
, daemon
->workspacename
, keyname
, name
, qtype
, nons
);
2101 return prove_non_existence_nsec3(header
, plen
, nsecs
, nsec_count
, daemon
->workspacename
, keyname
, name
, qtype
, NULL
, nons
);
2104 /* Chase the CNAME chain in the packet until the first record which _doesn't validate.
2105 Needed for proving answer in unsigned space.
2108 STAT_INSECURE - name of first non-secure record in name
2110 int dnssec_chase_cname(time_t now
, struct dns_header
*header
, size_t plen
, char *name
, char *keyname
)
2112 unsigned char *p
= (unsigned char *)(header
+1);
2113 int type
, class, qclass
, rdlen
, j
, rc
;
2114 int cname_count
= CNAME_CHAIN
;
2117 if (!extract_name(header
, plen
, &p
, name
, 1, 4))
2121 GETSHORT(qclass
, p
);
2125 for (j
= ntohs(header
->ancount
); j
!= 0; j
--)
2127 if (!(rc
= extract_name(header
, plen
, &p
, name
, 0, 10)))
2128 return STAT_BOGUS
; /* bad packet */
2135 /* Not target, loop */
2136 if (rc
== 2 || qclass
!= class)
2138 if (!ADD_RDLEN(header
, p
, plen
, rdlen
))
2143 /* Got to end of CNAME chain. */
2144 if (type
!= T_CNAME
)
2145 return STAT_INSECURE
;
2147 /* validate CNAME chain, return if insecure or need more data */
2148 rc
= validate_rrset(now
, header
, plen
, class, type
, name
, keyname
, NULL
, NULL
, 0, 0, 0);
2149 if (rc
!= STAT_SECURE
)
2151 if (rc
== STAT_NO_SIG
)
2156 /* Loop down CNAME chain/ */
2157 if (!cname_count
-- ||
2158 !extract_name(header
, plen
, &p
, name
, 1, 0) ||
2159 !(p
= skip_questions(header
, plen
)))
2165 /* End of CNAME chain */
2166 return STAT_INSECURE
;
2171 /* Compute keytag (checksum to quickly index a key). See RFC4034 */
2172 int dnskey_keytag(int alg
, int flags
, unsigned char *key
, int keylen
)
2176 /* Algorithm 1 (RSAMD5) has a different (older) keytag calculation algorithm.
2177 See RFC4034, Appendix B.1 */
2178 return key
[keylen
-4] * 256 + key
[keylen
-3];
2182 unsigned long ac
= flags
+ 0x300 + alg
;
2185 for (i
= 0; i
< keylen
; ++i
)
2186 ac
+= (i
& 1) ? key
[i
] : key
[i
] << 8;
2188 ac
+= (ac
>> 16) & 0xffff;
2193 size_t dnssec_generate_query(struct dns_header
*header
, char *end
, char *name
, int class,
2194 int type
, union mysockaddr
*addr
, int edns_pktsz
)
2197 char *types
= querystr("dnssec-query", type
);
2200 if (addr
->sa
.sa_family
== AF_INET
)
2201 log_query(F_NOEXTRA
| F_DNSSEC
| F_IPV4
, name
, (struct all_addr
*)&addr
->in
.sin_addr
, types
);
2204 log_query(F_NOEXTRA
| F_DNSSEC
| F_IPV6
, name
, (struct all_addr
*)&addr
->in6
.sin6_addr
, types
);
2207 header
->qdcount
= htons(1);
2208 header
->ancount
= htons(0);
2209 header
->nscount
= htons(0);
2210 header
->arcount
= htons(0);
2212 header
->hb3
= HB3_RD
;
2213 SET_OPCODE(header
, QUERY
);
2214 /* For debugging, set Checking Disabled, otherwise, have the upstream check too,
2215 this allows it to select auth servers when one is returning bad data. */
2216 header
->hb4
= option_bool(OPT_DNSSEC_DEBUG
) ? HB4_CD
: 0;
2218 /* ID filled in later */
2220 p
= (unsigned char *)(header
+1);
2222 p
= do_rfc1035_name(p
, name
);
2227 ret
= add_do_bit(header
, p
- (unsigned char *)header
, end
);
2229 if (find_pseudoheader(header
, ret
, NULL
, &p
, NULL
))
2230 PUTSHORT(edns_pktsz
, p
);
2235 /* Go through a domain name, find "pointers" and fix them up based on how many bytes
2236 we've chopped out of the packet, or check they don't point into an elided part. */
2237 static int check_name(unsigned char **namep
, struct dns_header
*header
, size_t plen
, int fixup
, unsigned char **rrs
, int rr_count
)
2239 unsigned char *ansp
= *namep
;
2243 unsigned int label_type
;
2245 if (!CHECK_LEN(header
, ansp
, plen
, 1))
2248 label_type
= (*ansp
) & 0xc0;
2250 if (label_type
== 0xc0)
2252 /* pointer for compression. */
2253 unsigned int offset
;
2257 if (!CHECK_LEN(header
, ansp
, plen
, 2))
2260 offset
= ((*ansp
++) & 0x3f) << 8;
2263 p
= offset
+ (unsigned char *)header
;
2265 for (i
= 0; i
< rr_count
; i
++)
2270 offset
-= rrs
[i
] - rrs
[i
-1];
2272 /* does the pointer end up in an elided RR? */
2276 /* No, scale the pointer */
2280 *ansp
++ = (offset
>> 8) | 0xc0;
2281 *ansp
++ = offset
& 0xff;
2285 else if (label_type
== 0x80)
2286 return 0; /* reserved */
2287 else if (label_type
== 0x40)
2289 /* Extended label type */
2292 if (!CHECK_LEN(header
, ansp
, plen
, 2))
2295 if (((*ansp
++) & 0x3f) != 1)
2296 return 0; /* we only understand bitstrings */
2298 count
= *(ansp
++); /* Bits in bitstring */
2300 if (count
== 0) /* count == 0 means 256 bits */
2303 ansp
+= ((count
-1)>>3)+1;
2306 { /* label type == 0 Bottom six bits is length */
2307 unsigned int len
= (*ansp
++) & 0x3f;
2309 if (!ADD_RDLEN(header
, ansp
, plen
, len
))
2313 break; /* zero length label marks the end. */
2322 /* Go through RRs and check or fixup the domain names contained within */
2323 static int check_rrs(unsigned char *p
, struct dns_header
*header
, size_t plen
, int fixup
, unsigned char **rrs
, int rr_count
)
2325 int i
, type
, class, rdlen
;
2328 for (i
= 0; i
< ntohs(header
->ancount
) + ntohs(header
->nscount
) + ntohs(header
->arcount
); i
++)
2332 if (!(p
= skip_name(p
, header
, plen
, 10)))
2340 if (type
!= T_NSEC
&& type
!= T_NSEC3
&& type
!= T_RRSIG
)
2342 /* fixup name of RR */
2343 if (!check_name(&pp
, header
, plen
, fixup
, rrs
, rr_count
))
2350 for (pp
= p
, d
= get_desc(type
); *d
!= (u16
)-1; d
++)
2354 else if (!check_name(&pp
, header
, plen
, fixup
, rrs
, rr_count
))
2360 if (!ADD_RDLEN(header
, p
, plen
, rdlen
))
2368 size_t filter_rrsigs(struct dns_header
*header
, size_t plen
)
2370 static unsigned char **rrs
;
2371 static int rr_sz
= 0;
2373 unsigned char *p
= (unsigned char *)(header
+1);
2374 int i
, rdlen
, qtype
, qclass
, rr_found
, chop_an
, chop_ns
, chop_ar
;
2376 if (ntohs(header
->qdcount
) != 1 ||
2377 !(p
= skip_name(p
, header
, plen
, 4)))
2381 GETSHORT(qclass
, p
);
2383 /* First pass, find pointers to start and end of all the records we wish to elide:
2384 records added for DNSSEC, unless explicity queried for */
2385 for (rr_found
= 0, chop_ns
= 0, chop_an
= 0, chop_ar
= 0, i
= 0;
2386 i
< ntohs(header
->ancount
) + ntohs(header
->nscount
) + ntohs(header
->arcount
);
2389 unsigned char *pstart
= p
;
2392 if (!(p
= skip_name(p
, header
, plen
, 10)))
2400 if ((type
== T_NSEC
|| type
== T_NSEC3
|| type
== T_RRSIG
) &&
2401 (type
!= qtype
|| class != qclass
))
2403 if (!expand_workspace(&rrs
, &rr_sz
, rr_found
+ 1))
2406 rrs
[rr_found
++] = pstart
;
2408 if (!ADD_RDLEN(header
, p
, plen
, rdlen
))
2411 rrs
[rr_found
++] = p
;
2413 if (i
< ntohs(header
->ancount
))
2415 else if (i
< (ntohs(header
->nscount
) + ntohs(header
->ancount
)))
2420 else if (!ADD_RDLEN(header
, p
, plen
, rdlen
))
2424 /* Nothing to do. */
2428 /* Second pass, look for pointers in names in the records we're keeping and make sure they don't
2429 point to records we're going to elide. This is theoretically possible, but unlikely. If
2430 it happens, we give up and leave the answer unchanged. */
2431 p
= (unsigned char *)(header
+1);
2433 /* question first */
2434 if (!check_name(&p
, header
, plen
, 0, rrs
, rr_found
))
2436 p
+= 4; /* qclass, qtype */
2438 /* Now answers and NS */
2439 if (!check_rrs(p
, header
, plen
, 0, rrs
, rr_found
))
2442 /* Third pass, elide records */
2443 for (p
= rrs
[0], i
= 1; i
< rr_found
; i
+= 2)
2445 unsigned char *start
= rrs
[i
];
2446 unsigned char *end
= (i
!= rr_found
- 1) ? rrs
[i
+1] : ((unsigned char *)(header
+1)) + plen
;
2448 memmove(p
, start
, end
-start
);
2452 plen
= p
- (unsigned char *)header
;
2453 header
->ancount
= htons(ntohs(header
->ancount
) - chop_an
);
2454 header
->nscount
= htons(ntohs(header
->nscount
) - chop_ns
);
2455 header
->arcount
= htons(ntohs(header
->arcount
) - chop_ar
);
2457 /* Fourth pass, fix up pointers in the remaining records */
2458 p
= (unsigned char *)(header
+1);
2460 check_name(&p
, header
, plen
, 1, rrs
, rr_found
);
2461 p
+= 4; /* qclass, qtype */
2463 check_rrs(p
, header
, plen
, 1, rrs
, rr_found
);
2468 unsigned char* hash_questions(struct dns_header
*header
, size_t plen
, char *name
)
2472 unsigned char *p
= (unsigned char *)(header
+1);
2473 const struct nettle_hash
*hash
;
2475 unsigned char *digest
;
2477 if (!(hash
= hash_find("sha1")) || !hash_init(hash
, &ctx
, &digest
))
2480 for (q
= ntohs(header
->qdcount
); q
!= 0; q
--)
2482 if (!extract_name(header
, plen
, &p
, name
, 1, 4))
2483 break; /* bad packet */
2485 len
= to_wire(name
);
2486 hash
->update(ctx
, len
, (unsigned char *)name
);
2487 /* CRC the class and type as well */
2488 hash
->update(ctx
, 4, p
);
2491 if (!CHECK_LEN(header
, p
, plen
, 0))
2492 break; /* bad packet */
2495 hash
->digest(ctx
, hash
->digest_size
, digest
);
2499 #endif /* HAVE_DNSSEC */