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8d41ebd8 | 1 | /* dnssec.c is Copyright (c) 2012 Giovanni Bajo <rasky@develer.com> |
0fc2f313 | 2 | and Copyright (c) 2012-2014 Simon Kelley |
8d41ebd8 GB |
3 | |
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. | |
8 | ||
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. | |
13 | ||
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/>. | |
16 | */ | |
e292e93d GB |
17 | |
18 | #include "dnsmasq.h" | |
0fc2f313 SK |
19 | |
20 | #ifdef HAVE_DNSSEC | |
21 | ||
86bec2d3 SK |
22 | #include <nettle/rsa.h> |
23 | #include <nettle/dsa.h> | |
c152dc84 SK |
24 | #ifndef NO_NETTLE_ECC |
25 | # include <nettle/ecdsa.h> | |
26 | # include <nettle/ecc-curve.h> | |
27 | #endif | |
86bec2d3 SK |
28 | #include <nettle/nettle-meta.h> |
29 | #include <gmp.h> | |
c3e0b9b6 | 30 | |
e292e93d GB |
31 | #define SERIAL_UNDEF -100 |
32 | #define SERIAL_EQ 0 | |
33 | #define SERIAL_LT -1 | |
34 | #define SERIAL_GT 1 | |
35 | ||
86bec2d3 SK |
36 | /* http://www.iana.org/assignments/ds-rr-types/ds-rr-types.xhtml */ |
37 | static char *ds_digest_name(int digest) | |
38 | { | |
39 | switch (digest) | |
40 | { | |
41 | case 1: return "sha1"; | |
42 | case 2: return "sha256"; | |
43 | case 3: return "gosthash94"; | |
44 | case 4: return "sha384"; | |
45 | default: return NULL; | |
46 | } | |
47 | } | |
48 | ||
49 | /* http://www.iana.org/assignments/dns-sec-alg-numbers/dns-sec-alg-numbers.xhtml */ | |
50 | static char *algo_digest_name(int algo) | |
51 | { | |
52 | switch (algo) | |
53 | { | |
54 | case 1: return "md5"; | |
55 | case 3: return "sha1"; | |
56 | case 5: return "sha1"; | |
57 | case 6: return "sha1"; | |
58 | case 7: return "sha1"; | |
59 | case 8: return "sha256"; | |
60 | case 10: return "sha512"; | |
61 | case 12: return "gosthash94"; | |
62 | case 13: return "sha256"; | |
63 | case 14: return "sha384"; | |
64 | default: return NULL; | |
65 | } | |
66 | } | |
67 | ||
68 | /* Find pointer to correct hash function in nettle library */ | |
69 | static const struct nettle_hash *hash_find(char *name) | |
70 | { | |
71 | int i; | |
72 | ||
73 | if (!name) | |
74 | return NULL; | |
75 | ||
76 | for (i = 0; nettle_hashes[i]; i++) | |
77 | { | |
78 | if (strcmp(nettle_hashes[i]->name, name) == 0) | |
79 | return nettle_hashes[i]; | |
80 | } | |
81 | ||
82 | return NULL; | |
83 | } | |
84 | ||
85 | /* expand ctx and digest memory allocations if necessary and init hash function */ | |
86 | static int hash_init(const struct nettle_hash *hash, void **ctxp, unsigned char **digestp) | |
87 | { | |
88 | static void *ctx = NULL; | |
89 | static unsigned char *digest = NULL; | |
90 | static unsigned int ctx_sz = 0; | |
91 | static unsigned int digest_sz = 0; | |
92 | ||
93 | void *new; | |
94 | ||
95 | if (ctx_sz < hash->context_size) | |
96 | { | |
97 | if (!(new = whine_malloc(hash->context_size))) | |
98 | return 0; | |
99 | if (ctx) | |
100 | free(ctx); | |
101 | ctx = new; | |
102 | ctx_sz = hash->context_size; | |
103 | } | |
104 | ||
105 | if (digest_sz < hash->digest_size) | |
106 | { | |
107 | if (!(new = whine_malloc(hash->digest_size))) | |
108 | return 0; | |
109 | if (digest) | |
110 | free(digest); | |
111 | digest = new; | |
112 | digest_sz = hash->digest_size; | |
113 | } | |
114 | ||
115 | *ctxp = ctx; | |
116 | *digestp = digest; | |
117 | ||
118 | hash->init(ctx); | |
119 | ||
120 | return 1; | |
121 | } | |
122 | ||
123 | static int rsa_verify(struct blockdata *key_data, unsigned int key_len, unsigned char *sig, size_t sig_len, | |
124 | unsigned char *digest, int algo) | |
125 | { | |
126 | unsigned char *p; | |
127 | size_t exp_len; | |
128 | ||
129 | static struct rsa_public_key *key = NULL; | |
130 | static mpz_t sig_mpz; | |
131 | ||
132 | if (key == NULL) | |
133 | { | |
134 | if (!(key = whine_malloc(sizeof(struct rsa_public_key)))) | |
135 | return 0; | |
136 | ||
137 | nettle_rsa_public_key_init(key); | |
138 | mpz_init(sig_mpz); | |
139 | } | |
140 | ||
141 | if ((key_len < 3) || !(p = blockdata_retrieve(key_data, key_len, NULL))) | |
142 | return 0; | |
143 | ||
144 | key_len--; | |
145 | if ((exp_len = *p++) == 0) | |
146 | { | |
147 | GETSHORT(exp_len, p); | |
148 | key_len -= 2; | |
149 | } | |
150 | ||
151 | if (exp_len >= key_len) | |
152 | return 0; | |
153 | ||
154 | key->size = key_len - exp_len; | |
155 | mpz_import(key->e, exp_len, 1, 1, 0, 0, p); | |
156 | mpz_import(key->n, key->size, 1, 1, 0, 0, p + exp_len); | |
157 | ||
158 | mpz_import(sig_mpz, sig_len, 1, 1, 0, 0, sig); | |
159 | ||
160 | switch (algo) | |
161 | { | |
162 | case 1: | |
163 | return nettle_rsa_md5_verify_digest(key, digest, sig_mpz); | |
164 | case 5: case 7: | |
165 | return nettle_rsa_sha1_verify_digest(key, digest, sig_mpz); | |
166 | case 8: | |
167 | return nettle_rsa_sha256_verify_digest(key, digest, sig_mpz); | |
168 | case 10: | |
169 | return nettle_rsa_sha512_verify_digest(key, digest, sig_mpz); | |
170 | } | |
171 | ||
172 | return 0; | |
173 | } | |
174 | ||
175 | static int dsa_verify(struct blockdata *key_data, unsigned int key_len, unsigned char *sig, size_t sig_len, | |
176 | unsigned char *digest, int algo) | |
177 | { | |
178 | unsigned char *p; | |
179 | unsigned int t; | |
180 | ||
181 | static struct dsa_public_key *key = NULL; | |
182 | static struct dsa_signature *sig_struct; | |
183 | ||
184 | if (key == NULL) | |
185 | { | |
186 | if (!(sig_struct = whine_malloc(sizeof(struct dsa_signature))) || | |
187 | !(key = whine_malloc(sizeof(struct dsa_public_key)))) | |
188 | return 0; | |
189 | ||
190 | nettle_dsa_public_key_init(key); | |
191 | nettle_dsa_signature_init(sig_struct); | |
192 | } | |
193 | ||
194 | if ((sig_len < 41) || !(p = blockdata_retrieve(key_data, key_len, NULL))) | |
195 | return 0; | |
196 | ||
197 | t = *p++; | |
198 | ||
199 | if (key_len < (213 + (t * 24))) | |
200 | return 0; | |
ebe95a83 | 201 | |
86bec2d3 SK |
202 | mpz_import(key->q, 20, 1, 1, 0, 0, p); p += 20; |
203 | mpz_import(key->p, 64 + (t*8), 1, 1, 0, 0, p); p += 64 + (t*8); | |
204 | mpz_import(key->g, 64 + (t*8), 1, 1, 0, 0, p); p += 64 + (t*8); | |
205 | mpz_import(key->y, 64 + (t*8), 1, 1, 0, 0, p); p += 64 + (t*8); | |
206 | ||
207 | mpz_import(sig_struct->r, 20, 1, 1, 0, 0, sig+1); | |
208 | mpz_import(sig_struct->s, 20, 1, 1, 0, 0, sig+21); | |
209 | ||
210 | (void)algo; | |
ebe95a83 | 211 | |
86bec2d3 SK |
212 | return nettle_dsa_sha1_verify_digest(key, digest, sig_struct); |
213 | } | |
214 | ||
c152dc84 SK |
215 | #ifndef NO_NETTLE_ECC |
216 | static int dnsmasq_ecdsa_verify(struct blockdata *key_data, unsigned int key_len, | |
217 | unsigned char *sig, size_t sig_len, | |
ebe95a83 SK |
218 | unsigned char *digest, size_t digest_len, int algo) |
219 | { | |
220 | unsigned char *p; | |
221 | unsigned int t; | |
222 | struct ecc_point *key; | |
223 | ||
224 | static struct ecc_point *key_256 = NULL, *key_384 = NULL; | |
225 | static mpz_t x, y; | |
226 | static struct dsa_signature *sig_struct; | |
227 | ||
228 | if (!sig_struct) | |
229 | { | |
230 | if (!(sig_struct = whine_malloc(sizeof(struct dsa_signature)))) | |
231 | return 0; | |
232 | ||
233 | nettle_dsa_signature_init(sig_struct); | |
234 | mpz_init(x); | |
235 | mpz_init(y); | |
236 | } | |
237 | ||
238 | switch (algo) | |
239 | { | |
240 | case 13: | |
241 | if (!key_256) | |
242 | { | |
243 | if (!(key_256 = whine_malloc(sizeof(struct ecc_point)))) | |
244 | return 0; | |
245 | ||
246 | nettle_ecc_point_init(key_256, &nettle_secp_256r1); | |
247 | } | |
248 | ||
249 | key = key_256; | |
250 | t = 32; | |
251 | break; | |
252 | ||
253 | case 14: | |
254 | if (!key_384) | |
255 | { | |
256 | if (!(key_384 = whine_malloc(sizeof(struct ecc_point)))) | |
257 | return 0; | |
258 | ||
259 | nettle_ecc_point_init(key_384, &nettle_secp_384r1); | |
260 | } | |
261 | ||
262 | key = key_384; | |
263 | t = 48; | |
264 | break; | |
265 | ||
266 | default: | |
267 | return 0; | |
268 | } | |
269 | ||
270 | if (sig_len != 2*t || key_len != 2*t || | |
271 | (p = blockdata_retrieve(key_data, key_len, NULL))) | |
272 | return 0; | |
273 | ||
274 | mpz_import(x, t , 1, 1, 0, 0, p); | |
275 | mpz_import(y, t , 1, 1, 0, 0, p + t); | |
276 | ||
277 | if (!ecc_point_set(key, x, y)) | |
278 | return 0; | |
279 | ||
280 | mpz_import(sig_struct->r, t, 1, 1, 0, 0, sig); | |
281 | mpz_import(sig_struct->s, t, 1, 1, 0, 0, sig + t); | |
282 | ||
283 | return nettle_ecdsa_verify(key, digest_len, digest, sig_struct); | |
284 | } | |
c152dc84 SK |
285 | #endif |
286 | ||
86bec2d3 | 287 | static int verify(struct blockdata *key_data, unsigned int key_len, unsigned char *sig, size_t sig_len, |
ebe95a83 | 288 | unsigned char *digest, size_t digest_len, int algo) |
86bec2d3 | 289 | { |
7b1eae4f SK |
290 | (void)digest_len; |
291 | ||
86bec2d3 SK |
292 | switch (algo) |
293 | { | |
294 | case 1: case 5: case 7: case 8: case 10: | |
295 | return rsa_verify(key_data, key_len, sig, sig_len, digest, algo); | |
296 | ||
297 | case 3: case 6: | |
298 | return dsa_verify(key_data, key_len, sig, sig_len, digest, algo); | |
c152dc84 SK |
299 | |
300 | #ifndef NO_NETTLE_ECC | |
ebe95a83 SK |
301 | case 13: case 14: |
302 | return dnsmasq_ecdsa_verify(key_data, key_len, sig, sig_len, digest, digest_len, algo); | |
c152dc84 SK |
303 | #endif |
304 | } | |
86bec2d3 SK |
305 | |
306 | return 0; | |
307 | } | |
308 | ||
0fc2f313 SK |
309 | /* Convert from presentation format to wire format, in place. |
310 | Also map UC -> LC. | |
311 | Note that using extract_name to get presentation format | |
312 | then calling to_wire() removes compression and maps case, | |
313 | thus generating names in canonical form. | |
314 | Calling to_wire followed by from_wire is almost an identity, | |
315 | except that the UC remains mapped to LC. | |
316 | */ | |
317 | static int to_wire(char *name) | |
7f0485cf | 318 | { |
0fc2f313 SK |
319 | unsigned char *l, *p, term; |
320 | int len; | |
321 | ||
322 | for (l = (unsigned char*)name; *l != 0; l = p) | |
323 | { | |
324 | for (p = l; *p != '.' && *p != 0; p++) | |
325 | if (*p >= 'A' && *p <= 'Z') | |
326 | *p = *p - 'A' + 'a'; | |
327 | ||
328 | term = *p; | |
329 | ||
330 | if ((len = p - l) != 0) | |
331 | memmove(l+1, l, len); | |
332 | *l = len; | |
333 | ||
334 | p++; | |
335 | ||
336 | if (term == 0) | |
337 | *p = 0; | |
338 | } | |
339 | ||
340 | return l + 1 - (unsigned char *)name; | |
7f0485cf GB |
341 | } |
342 | ||
0fc2f313 SK |
343 | /* Note: no compression allowed in input. */ |
344 | static void from_wire(char *name) | |
13e435eb | 345 | { |
0fc2f313 SK |
346 | unsigned char *l; |
347 | int len; | |
13e435eb | 348 | |
0fc2f313 | 349 | for (l = (unsigned char *)name; *l != 0; l += len+1) |
13e435eb | 350 | { |
0fc2f313 SK |
351 | len = *l; |
352 | memmove(l, l+1, len); | |
353 | l[len] = '.'; | |
13e435eb | 354 | } |
7f0485cf | 355 | |
e3f14558 | 356 | if ((char *)l != name) |
bd9b3cf5 | 357 | *(l-1) = 0; |
13e435eb GB |
358 | } |
359 | ||
5ada8885 SK |
360 | /* Input in presentation format */ |
361 | static int count_labels(char *name) | |
362 | { | |
363 | int i; | |
364 | ||
365 | if (*name == 0) | |
366 | return 0; | |
367 | ||
368 | for (i = 0; *name; name++) | |
369 | if (*name == '.') | |
370 | i++; | |
371 | ||
372 | return i+1; | |
373 | } | |
374 | ||
5f8e58f4 SK |
375 | /* Implement RFC1982 wrapped compare for 32-bit numbers */ |
376 | static int serial_compare_32(unsigned long s1, unsigned long s2) | |
377 | { | |
378 | if (s1 == s2) | |
379 | return SERIAL_EQ; | |
0ca895f5 | 380 | |
5f8e58f4 SK |
381 | if ((s1 < s2 && (s2 - s1) < (1UL<<31)) || |
382 | (s1 > s2 && (s1 - s2) > (1UL<<31))) | |
383 | return SERIAL_LT; | |
384 | if ((s1 < s2 && (s2 - s1) > (1UL<<31)) || | |
385 | (s1 > s2 && (s1 - s2) < (1UL<<31))) | |
386 | return SERIAL_GT; | |
387 | return SERIAL_UNDEF; | |
388 | } | |
0852d76b | 389 | |
5f8e58f4 SK |
390 | /* Check whether today/now is between date_start and date_end */ |
391 | static int check_date_range(unsigned long date_start, unsigned long date_end) | |
0852d76b | 392 | { |
5f8e58f4 SK |
393 | unsigned long curtime = time(0); |
394 | ||
395 | /* We must explicitly check against wanted values, because of SERIAL_UNDEF */ | |
396 | return serial_compare_32(curtime, date_start) == SERIAL_GT | |
397 | && serial_compare_32(curtime, date_end) == SERIAL_LT; | |
398 | } | |
f119ed38 | 399 | |
5f8e58f4 SK |
400 | static u16 *get_desc(int type) |
401 | { | |
402 | /* List of RRtypes which include domains in the data. | |
403 | 0 -> domain | |
404 | integer -> no of plain bytes | |
405 | -1 -> end | |
406 | ||
407 | zero is not a valid RRtype, so the final entry is returned for | |
408 | anything which needs no mangling. | |
409 | */ | |
410 | ||
411 | static u16 rr_desc[] = | |
412 | { | |
413 | T_NS, 0, -1, | |
414 | T_MD, 0, -1, | |
415 | T_MF, 0, -1, | |
416 | T_CNAME, 0, -1, | |
417 | T_SOA, 0, 0, -1, | |
418 | T_MB, 0, -1, | |
419 | T_MG, 0, -1, | |
420 | T_MR, 0, -1, | |
421 | T_PTR, 0, -1, | |
422 | T_MINFO, 0, 0, -1, | |
423 | T_MX, 2, 0, -1, | |
424 | T_RP, 0, 0, -1, | |
425 | T_AFSDB, 2, 0, -1, | |
426 | T_RT, 2, 0, -1, | |
427 | T_SIG, 18, 0, -1, | |
428 | T_PX, 2, 0, 0, -1, | |
429 | T_NXT, 0, -1, | |
430 | T_KX, 2, 0, -1, | |
431 | T_SRV, 6, 0, -1, | |
432 | T_DNAME, 0, -1, | |
5f8e58f4 SK |
433 | 0, -1 /* wildcard/catchall */ |
434 | }; | |
435 | ||
436 | u16 *p = rr_desc; | |
437 | ||
438 | while (*p != type && *p != 0) | |
439 | while (*p++ != (u16)-1); | |
f119ed38 | 440 | |
5f8e58f4 SK |
441 | return p+1; |
442 | } | |
0852d76b | 443 | |
5f8e58f4 SK |
444 | /* Return bytes of canonicalised rdata, when the return value is zero, the remaining |
445 | data, pointed to by *p, should be used raw. */ | |
446 | static int get_rdata(struct dns_header *header, size_t plen, unsigned char *end, char *buff, | |
447 | unsigned char **p, u16 **desc) | |
448 | { | |
449 | int d = **desc; | |
450 | ||
451 | (*desc)++; | |
452 | ||
453 | /* No more data needs mangling */ | |
454 | if (d == (u16)-1) | |
455 | return 0; | |
456 | ||
457 | if (d == 0 && extract_name(header, plen, p, buff, 1, 0)) | |
458 | /* domain-name, canonicalise */ | |
459 | return to_wire(buff); | |
460 | else | |
461 | { | |
462 | /* plain data preceding a domain-name, don't run off the end of the data */ | |
463 | if ((end - *p) < d) | |
464 | d = end - *p; | |
465 | ||
466 | if (d != 0) | |
467 | { | |
468 | memcpy(buff, *p, d); | |
469 | *p += d; | |
470 | } | |
471 | ||
472 | return d; | |
473 | } | |
0852d76b GB |
474 | } |
475 | ||
613ad15d SK |
476 | static int expand_workspace(unsigned char ***wkspc, int *sz, int new) |
477 | { | |
478 | unsigned char **p; | |
479 | int new_sz = *sz; | |
480 | ||
481 | if (new_sz > new) | |
482 | return 1; | |
483 | ||
484 | if (new >= 100) | |
485 | return 0; | |
486 | ||
487 | new_sz += 5; | |
488 | ||
489 | if (!(p = whine_malloc((new_sz) * sizeof(unsigned char **)))) | |
490 | return 0; | |
491 | ||
492 | if (*wkspc) | |
493 | { | |
494 | memcpy(p, *wkspc, *sz * sizeof(unsigned char **)); | |
495 | free(*wkspc); | |
496 | } | |
497 | ||
498 | *wkspc = p; | |
499 | *sz = new_sz; | |
00a5b5d4 SK |
500 | |
501 | return 1; | |
613ad15d SK |
502 | } |
503 | ||
5f8e58f4 SK |
504 | /* Bubble sort the RRset into the canonical order. |
505 | Note that the byte-streams from two RRs may get unsynced: consider | |
506 | RRs which have two domain-names at the start and then other data. | |
507 | The domain-names may have different lengths in each RR, but sort equal | |
508 | ||
509 | ------------ | |
510 | |abcde|fghi| | |
511 | ------------ | |
512 | |abcd|efghi| | |
513 | ------------ | |
514 | ||
515 | leaving the following bytes as deciding the order. Hence the nasty left1 and left2 variables. | |
516 | */ | |
517 | ||
518 | static void sort_rrset(struct dns_header *header, size_t plen, u16 *rr_desc, int rrsetidx, | |
519 | unsigned char **rrset, char *buff1, char *buff2) | |
c3e0b9b6 | 520 | { |
5f8e58f4 | 521 | int swap, quit, i; |
0fc2f313 | 522 | |
5f8e58f4 SK |
523 | do |
524 | { | |
525 | for (swap = 0, i = 0; i < rrsetidx-1; i++) | |
526 | { | |
527 | int rdlen1, rdlen2, left1, left2, len1, len2, len, rc; | |
528 | u16 *dp1, *dp2; | |
529 | unsigned char *end1, *end2; | |
5107ace1 SK |
530 | /* Note that these have been determined to be OK previously, |
531 | so we don't need to check for NULL return here. */ | |
5f8e58f4 SK |
532 | unsigned char *p1 = skip_name(rrset[i], header, plen, 10); |
533 | unsigned char *p2 = skip_name(rrset[i+1], header, plen, 10); | |
534 | ||
535 | p1 += 8; /* skip class, type, ttl */ | |
536 | GETSHORT(rdlen1, p1); | |
537 | end1 = p1 + rdlen1; | |
538 | ||
539 | p2 += 8; /* skip class, type, ttl */ | |
540 | GETSHORT(rdlen2, p2); | |
541 | end2 = p2 + rdlen2; | |
542 | ||
543 | dp1 = dp2 = rr_desc; | |
544 | ||
1486a9c7 | 545 | for (quit = 0, left1 = 0, left2 = 0, len1 = 0, len2 = 0; !quit;) |
5f8e58f4 | 546 | { |
1486a9c7 SK |
547 | if (left1 != 0) |
548 | memmove(buff1, buff1 + len1 - left1, left1); | |
549 | ||
5f8e58f4 SK |
550 | if ((len1 = get_rdata(header, plen, end1, buff1 + left1, &p1, &dp1)) == 0) |
551 | { | |
552 | quit = 1; | |
553 | len1 = end1 - p1; | |
554 | memcpy(buff1 + left1, p1, len1); | |
555 | } | |
556 | len1 += left1; | |
557 | ||
1486a9c7 SK |
558 | if (left2 != 0) |
559 | memmove(buff2, buff2 + len2 - left2, left2); | |
560 | ||
5f8e58f4 SK |
561 | if ((len2 = get_rdata(header, plen, end2, buff2 + left2, &p2, &dp2)) == 0) |
562 | { | |
563 | quit = 1; | |
564 | len2 = end2 - p2; | |
565 | memcpy(buff2 + left2, p2, len2); | |
566 | } | |
567 | len2 += left2; | |
568 | ||
569 | if (len1 > len2) | |
1486a9c7 | 570 | left1 = len1 - len2, left2 = 0, len = len2; |
5f8e58f4 | 571 | else |
1486a9c7 | 572 | left2 = len2 - len1, left1 = 0, len = len1; |
5f8e58f4 | 573 | |
6fd6dacb | 574 | rc = (len == 0) ? 0 : memcmp(buff1, buff2, len); |
5f8e58f4 | 575 | |
4619d946 | 576 | if (rc > 0 || (rc == 0 && quit && len1 > len2)) |
5f8e58f4 SK |
577 | { |
578 | unsigned char *tmp = rrset[i+1]; | |
579 | rrset[i+1] = rrset[i]; | |
580 | rrset[i] = tmp; | |
581 | swap = quit = 1; | |
582 | } | |
6fd6dacb SK |
583 | else if (rc < 0) |
584 | quit = 1; | |
5f8e58f4 SK |
585 | } |
586 | } | |
587 | } while (swap); | |
588 | } | |
c3e0b9b6 | 589 | |
5f8e58f4 SK |
590 | /* Validate a single RRset (class, type, name) in the supplied DNS reply |
591 | Return code: | |
592 | STAT_SECURE if it validates. | |
5107ace1 | 593 | STAT_SECURE_WILDCARD if it validates and is the result of wildcard expansion. |
00a5b5d4 | 594 | STAT_NO_SIG no RRsigs found. |
5f8e58f4 SK |
595 | STAT_INSECURE can't validate (no RRSIG, bad packet). |
596 | STAT_BOGUS signature is wrong. | |
597 | STAT_NEED_KEY need DNSKEY to complete validation (name is returned in keyname) | |
598 | ||
599 | if key is non-NULL, use that key, which has the algo and tag given in the params of those names, | |
600 | otherwise find the key in the cache. | |
5107ace1 SK |
601 | |
602 | name is unchanged on exit. keyname is used as workspace and trashed. | |
5f8e58f4 SK |
603 | */ |
604 | static int validate_rrset(time_t now, struct dns_header *header, size_t plen, int class, | |
e7829aef | 605 | int type, char *name, char *keyname, struct blockdata *key, int keylen, int algo_in, int keytag_in) |
5f8e58f4 SK |
606 | { |
607 | static unsigned char **rrset = NULL, **sigs = NULL; | |
608 | static int rrset_sz = 0, sig_sz = 0; | |
0fc2f313 | 609 | |
5f8e58f4 | 610 | unsigned char *p; |
5ada8885 | 611 | int rrsetidx, sigidx, res, rdlen, j, name_labels; |
5f8e58f4 SK |
612 | struct crec *crecp = NULL; |
613 | int type_covered, algo, labels, orig_ttl, sig_expiration, sig_inception, key_tag; | |
614 | u16 *rr_desc = get_desc(type); | |
c3e0b9b6 | 615 | |
5f8e58f4 SK |
616 | if (!(p = skip_questions(header, plen))) |
617 | return STAT_INSECURE; | |
c3e0b9b6 | 618 | |
5ada8885 SK |
619 | name_labels = count_labels(name); /* For 4035 5.3.2 check */ |
620 | ||
621 | /* look for RRSIGs for this RRset and get pointers to each RR in the set. */ | |
5f8e58f4 SK |
622 | for (rrsetidx = 0, sigidx = 0, j = ntohs(header->ancount) + ntohs(header->nscount); |
623 | j != 0; j--) | |
624 | { | |
625 | unsigned char *pstart, *pdata; | |
b98d22c1 | 626 | int stype, sclass; |
c3e0b9b6 | 627 | |
5f8e58f4 SK |
628 | pstart = p; |
629 | ||
630 | if (!(res = extract_name(header, plen, &p, name, 0, 10))) | |
631 | return STAT_INSECURE; /* bad packet */ | |
632 | ||
633 | GETSHORT(stype, p); | |
634 | GETSHORT(sclass, p); | |
b98d22c1 | 635 | p += 4; /* TTL */ |
5f8e58f4 SK |
636 | |
637 | pdata = p; | |
c3e0b9b6 | 638 | |
5f8e58f4 SK |
639 | GETSHORT(rdlen, p); |
640 | ||
e7829aef SK |
641 | if (!CHECK_LEN(header, p, plen, rdlen)) |
642 | return STAT_INSECURE; | |
643 | ||
5f8e58f4 SK |
644 | if (res == 1 && sclass == class) |
645 | { | |
646 | if (stype == type) | |
647 | { | |
613ad15d SK |
648 | if (!expand_workspace(&rrset, &rrset_sz, rrsetidx)) |
649 | return STAT_INSECURE; | |
650 | ||
5f8e58f4 SK |
651 | rrset[rrsetidx++] = pstart; |
652 | } | |
653 | ||
654 | if (stype == T_RRSIG) | |
655 | { | |
613ad15d SK |
656 | if (rdlen < 18) |
657 | return STAT_INSECURE; /* bad packet */ | |
658 | ||
659 | GETSHORT(type_covered, p); | |
660 | ||
661 | if (type_covered == type) | |
662 | { | |
663 | if (!expand_workspace(&sigs, &sig_sz, sigidx)) | |
664 | return STAT_INSECURE; | |
665 | ||
666 | sigs[sigidx++] = pdata; | |
667 | } | |
668 | ||
669 | p = pdata + 2; /* restore for ADD_RDLEN */ | |
5f8e58f4 SK |
670 | } |
671 | } | |
613ad15d | 672 | |
5f8e58f4 SK |
673 | if (!ADD_RDLEN(header, p, plen, rdlen)) |
674 | return STAT_INSECURE; | |
675 | } | |
c3e0b9b6 | 676 | |
00a5b5d4 SK |
677 | /* RRset empty */ |
678 | if (rrsetidx == 0) | |
5f8e58f4 | 679 | return STAT_INSECURE; |
00a5b5d4 SK |
680 | |
681 | /* no RRSIGs */ | |
682 | if (sigidx == 0) | |
683 | return STAT_NO_SIG; | |
5f8e58f4 SK |
684 | |
685 | /* Sort RRset records into canonical order. | |
d387380a | 686 | Note that at this point keyname and daemon->workspacename buffs are |
5f8e58f4 | 687 | unused, and used as workspace by the sort. */ |
d387380a | 688 | sort_rrset(header, plen, rr_desc, rrsetidx, rrset, daemon->workspacename, keyname); |
5f8e58f4 SK |
689 | |
690 | /* Now try all the sigs to try and find one which validates */ | |
691 | for (j = 0; j <sigidx; j++) | |
692 | { | |
d387380a | 693 | unsigned char *psav, *sig, *digest; |
86bec2d3 SK |
694 | int i, wire_len, sig_len; |
695 | const struct nettle_hash *hash; | |
696 | void *ctx; | |
d387380a | 697 | char *name_start; |
5f8e58f4 SK |
698 | u32 nsigttl; |
699 | ||
700 | p = sigs[j]; | |
5ada8885 | 701 | GETSHORT(rdlen, p); /* rdlen >= 18 checked previously */ |
5f8e58f4 SK |
702 | psav = p; |
703 | ||
5ada8885 | 704 | p += 2; /* type_covered - already checked */ |
5f8e58f4 SK |
705 | algo = *p++; |
706 | labels = *p++; | |
707 | GETLONG(orig_ttl, p); | |
e7829aef SK |
708 | GETLONG(sig_expiration, p); |
709 | GETLONG(sig_inception, p); | |
5f8e58f4 SK |
710 | GETSHORT(key_tag, p); |
711 | ||
5f8e58f4 SK |
712 | if (!extract_name(header, plen, &p, keyname, 1, 0)) |
713 | return STAT_INSECURE; | |
d387380a SK |
714 | |
715 | /* RFC 4035 5.3.1 says that the Signer's Name field MUST equal | |
716 | the name of the zone containing the RRset. We can't tell that | |
717 | for certain, but we can check that the RRset name is equal to | |
718 | or encloses the signers name, which should be enough to stop | |
719 | an attacker using signatures made with the key of an unrelated | |
720 | zone he controls. Note that the root key is always allowed. */ | |
721 | if (*keyname != 0) | |
722 | { | |
723 | int failed = 0; | |
724 | ||
725 | for (name_start = name; !hostname_isequal(name_start, keyname); ) | |
726 | if ((name_start = strchr(name_start, '.'))) | |
727 | name_start++; /* chop a label off and try again */ | |
728 | else | |
729 | { | |
730 | failed = 1; | |
731 | break; | |
732 | } | |
733 | ||
734 | /* Bad sig, try another */ | |
735 | if (failed) | |
736 | continue; | |
737 | } | |
5f8e58f4 | 738 | |
d387380a | 739 | /* Other 5.3.1 checks */ |
e7829aef SK |
740 | if (!check_date_range(sig_inception, sig_expiration) || |
741 | labels > name_labels || | |
742 | !(hash = hash_find(algo_digest_name(algo))) || | |
743 | !hash_init(hash, &ctx, &digest)) | |
744 | continue; | |
745 | ||
5f8e58f4 SK |
746 | /* OK, we have the signature record, see if the relevant DNSKEY is in the cache. */ |
747 | if (!key && !(crecp = cache_find_by_name(NULL, keyname, now, F_DNSKEY))) | |
748 | return STAT_NEED_KEY; | |
749 | ||
86bec2d3 SK |
750 | sig = p; |
751 | sig_len = rdlen - (p - psav); | |
e7829aef | 752 | |
5f8e58f4 SK |
753 | nsigttl = htonl(orig_ttl); |
754 | ||
86bec2d3 | 755 | hash->update(ctx, 18, psav); |
5f8e58f4 | 756 | wire_len = to_wire(keyname); |
86bec2d3 | 757 | hash->update(ctx, (unsigned int)wire_len, (unsigned char*)keyname); |
5f8e58f4 SK |
758 | from_wire(keyname); |
759 | ||
5f8e58f4 SK |
760 | for (i = 0; i < rrsetidx; ++i) |
761 | { | |
762 | int seg; | |
763 | unsigned char *end, *cp; | |
764 | u16 len, *dp; | |
d387380a | 765 | |
5f8e58f4 SK |
766 | p = rrset[i]; |
767 | if (!extract_name(header, plen, &p, name, 1, 10)) | |
768 | return STAT_INSECURE; | |
5ada8885 | 769 | |
d387380a SK |
770 | name_start = name; |
771 | ||
5ada8885 SK |
772 | /* if more labels than in RRsig name, hash *.<no labels in rrsig labels field> 4035 5.3.2 */ |
773 | if (labels < name_labels) | |
774 | { | |
775 | int k; | |
776 | for (k = name_labels - labels; k != 0; k--) | |
777 | while (*name_start != '.' && *name_start != 0) | |
778 | name_start++; | |
779 | name_start--; | |
780 | *name_start = '*'; | |
781 | } | |
782 | ||
783 | wire_len = to_wire(name_start); | |
86bec2d3 SK |
784 | hash->update(ctx, (unsigned int)wire_len, (unsigned char *)name_start); |
785 | hash->update(ctx, 4, p); /* class and type */ | |
786 | hash->update(ctx, 4, (unsigned char *)&nsigttl); | |
5f8e58f4 SK |
787 | |
788 | p += 8; /* skip class, type, ttl */ | |
789 | GETSHORT(rdlen, p); | |
5ada8885 SK |
790 | if (!CHECK_LEN(header, p, plen, rdlen)) |
791 | return STAT_INSECURE; | |
792 | ||
5f8e58f4 SK |
793 | end = p + rdlen; |
794 | ||
795 | /* canonicalise rdata and calculate length of same, use name buffer as workspace */ | |
796 | cp = p; | |
797 | dp = rr_desc; | |
798 | for (len = 0; (seg = get_rdata(header, plen, end, name, &cp, &dp)) != 0; len += seg); | |
799 | len += end - cp; | |
800 | len = htons(len); | |
86bec2d3 | 801 | hash->update(ctx, 2, (unsigned char *)&len); |
5f8e58f4 SK |
802 | |
803 | /* Now canonicalise again and digest. */ | |
804 | cp = p; | |
805 | dp = rr_desc; | |
806 | while ((seg = get_rdata(header, plen, end, name, &cp, &dp))) | |
86bec2d3 | 807 | hash->update(ctx, seg, (unsigned char *)name); |
5f8e58f4 | 808 | if (cp != end) |
86bec2d3 | 809 | hash->update(ctx, end - cp, cp); |
5f8e58f4 | 810 | } |
86bec2d3 SK |
811 | |
812 | hash->digest(ctx, hash->digest_size, digest); | |
813 | ||
5ada8885 SK |
814 | /* namebuff used for workspace above, restore to leave unchanged on exit */ |
815 | p = (unsigned char*)(rrset[0]); | |
816 | extract_name(header, plen, &p, name, 1, 0); | |
817 | ||
5f8e58f4 SK |
818 | if (key) |
819 | { | |
820 | if (algo_in == algo && keytag_in == key_tag && | |
ebe95a83 | 821 | verify(key, keylen, sig, sig_len, digest, hash->digest_size, algo)) |
5f8e58f4 SK |
822 | return STAT_SECURE; |
823 | } | |
824 | else | |
825 | { | |
826 | /* iterate through all possible keys 4035 5.3.1 */ | |
827 | for (; crecp; crecp = cache_find_by_name(crecp, keyname, now, F_DNSKEY)) | |
51ea3ca2 SK |
828 | if (crecp->addr.key.algo == algo && |
829 | crecp->addr.key.keytag == key_tag && | |
824202ef | 830 | crecp->uid == class && |
ebe95a83 | 831 | verify(crecp->addr.key.keydata, crecp->addr.key.keylen, sig, sig_len, digest, hash->digest_size, algo)) |
5107ace1 | 832 | return (labels < name_labels) ? STAT_SECURE_WILDCARD : STAT_SECURE; |
5f8e58f4 SK |
833 | } |
834 | } | |
835 | ||
836 | return STAT_BOGUS; | |
837 | } | |
838 | ||
0fc2f313 | 839 | /* The DNS packet is expected to contain the answer to a DNSKEY query. |
c3e0b9b6 SK |
840 | Put all DNSKEYs in the answer which are valid into the cache. |
841 | return codes: | |
842 | STAT_INSECURE bad packet, no DNSKEYs in reply. | |
843 | STAT_SECURE At least one valid DNSKEY found and in cache. | |
0fc2f313 SK |
844 | STAT_BOGUS No DNSKEYs found, which can be validated with DS, |
845 | or self-sign for DNSKEY RRset is not valid. | |
846 | STAT_NEED_DS DS records to validate a key not found, name in keyname | |
c3e0b9b6 SK |
847 | */ |
848 | int dnssec_validate_by_ds(time_t now, struct dns_header *header, size_t plen, char *name, char *keyname, int class) | |
849 | { | |
0fc2f313 | 850 | unsigned char *psave, *p = (unsigned char *)(header+1); |
c3e0b9b6 | 851 | struct crec *crecp, *recp1; |
8d718cbb | 852 | int rc, j, qtype, qclass, ttl, rdlen, flags, algo, valid, keytag, type_covered; |
c3e0b9b6 | 853 | struct blockdata *key; |
51ea3ca2 | 854 | struct all_addr a; |
c3e0b9b6 | 855 | |
5f8e58f4 SK |
856 | if (ntohs(header->qdcount) != 1 || |
857 | !extract_name(header, plen, &p, name, 1, 4)) | |
8d718cbb | 858 | return STAT_INSECURE; |
5f8e58f4 | 859 | |
c3e0b9b6 SK |
860 | GETSHORT(qtype, p); |
861 | GETSHORT(qclass, p); | |
862 | ||
0fc2f313 | 863 | if (qtype != T_DNSKEY || qclass != class || ntohs(header->ancount) == 0) |
f01d7be6 | 864 | return STAT_BOGUS; |
c3e0b9b6 | 865 | |
b8eac191 | 866 | /* See if we have cached a DS record which validates this key */ |
0fc2f313 SK |
867 | if (!(crecp = cache_find_by_name(NULL, name, now, F_DS))) |
868 | { | |
869 | strcpy(keyname, name); | |
870 | return STAT_NEED_DS; | |
871 | } | |
b8eac191 SK |
872 | |
873 | /* If we've cached that DS provably doesn't exist, result must be INSECURE */ | |
874 | if (crecp->flags & F_NEG) | |
875 | return STAT_INSECURE; | |
876 | ||
0fc2f313 | 877 | /* NOTE, we need to find ONE DNSKEY which matches the DS */ |
e7829aef | 878 | for (valid = 0, j = ntohs(header->ancount); j != 0 && !valid; j--) |
c3e0b9b6 SK |
879 | { |
880 | /* Ensure we have type, class TTL and length */ | |
0fc2f313 | 881 | if (!(rc = extract_name(header, plen, &p, name, 0, 10))) |
c3e0b9b6 SK |
882 | return STAT_INSECURE; /* bad packet */ |
883 | ||
884 | GETSHORT(qtype, p); | |
885 | GETSHORT(qclass, p); | |
886 | GETLONG(ttl, p); | |
887 | GETSHORT(rdlen, p); | |
6f468103 | 888 | |
0fc2f313 SK |
889 | if (!CHECK_LEN(header, p, plen, rdlen) || rdlen < 4) |
890 | return STAT_INSECURE; /* bad packet */ | |
891 | ||
6f468103 SK |
892 | if (qclass != class || qtype != T_DNSKEY || rc == 2) |
893 | { | |
894 | p += rdlen; | |
895 | continue; | |
896 | } | |
897 | ||
0fc2f313 | 898 | psave = p; |
c3e0b9b6 | 899 | |
c3e0b9b6 | 900 | GETSHORT(flags, p); |
0fc2f313 | 901 | if (*p++ != 3) |
f01d7be6 | 902 | return STAT_BOGUS; |
c3e0b9b6 | 903 | algo = *p++; |
0fc2f313 | 904 | keytag = dnskey_keytag(algo, flags, p, rdlen - 4); |
e7829aef | 905 | key = NULL; |
c3e0b9b6 | 906 | |
e7829aef SK |
907 | /* key must have zone key flag set */ |
908 | if (flags & 0x100) | |
909 | key = blockdata_alloc((char*)p, rdlen - 4); | |
c3e0b9b6 | 910 | |
0fc2f313 | 911 | p = psave; |
e7829aef | 912 | |
0fc2f313 | 913 | if (!ADD_RDLEN(header, p, plen, rdlen)) |
8d718cbb SK |
914 | { |
915 | if (key) | |
916 | blockdata_free(key); | |
917 | return STAT_INSECURE; /* bad packet */ | |
918 | } | |
919 | ||
e7829aef SK |
920 | /* No zone key flag or malloc failure */ |
921 | if (!key) | |
0fc2f313 SK |
922 | continue; |
923 | ||
924 | for (recp1 = crecp; recp1; recp1 = cache_find_by_name(recp1, name, now, F_DS)) | |
86bec2d3 SK |
925 | { |
926 | void *ctx; | |
927 | unsigned char *digest, *ds_digest; | |
928 | const struct nettle_hash *hash; | |
929 | ||
51ea3ca2 SK |
930 | if (recp1->addr.ds.algo == algo && |
931 | recp1->addr.ds.keytag == keytag && | |
824202ef | 932 | recp1->uid == class && |
51ea3ca2 | 933 | (hash = hash_find(ds_digest_name(recp1->addr.ds.digest))) && |
86bec2d3 | 934 | hash_init(hash, &ctx, &digest)) |
0fc2f313 | 935 | |
86bec2d3 SK |
936 | { |
937 | int wire_len = to_wire(name); | |
938 | ||
939 | /* Note that digest may be different between DSs, so | |
940 | we can't move this outside the loop. */ | |
941 | hash->update(ctx, (unsigned int)wire_len, (unsigned char *)name); | |
942 | hash->update(ctx, (unsigned int)rdlen, psave); | |
943 | hash->digest(ctx, hash->digest_size, digest); | |
944 | ||
945 | from_wire(name); | |
946 | ||
824202ef SK |
947 | if (recp1->addr.ds.keylen == (int)hash->digest_size && |
948 | (ds_digest = blockdata_retrieve(recp1->addr.key.keydata, recp1->addr.ds.keylen, NULL)) && | |
949 | memcmp(ds_digest, digest, recp1->addr.ds.keylen) == 0 && | |
f6a2b793 | 950 | validate_rrset(now, header, plen, class, T_DNSKEY, name, keyname, key, rdlen - 4, algo, keytag) == STAT_SECURE) |
86bec2d3 | 951 | { |
86bec2d3 | 952 | valid = 1; |
86bec2d3 SK |
953 | break; |
954 | } | |
955 | } | |
956 | } | |
e7829aef | 957 | blockdata_free(key); |
c3e0b9b6 | 958 | } |
c3e0b9b6 | 959 | |
0fc2f313 SK |
960 | if (valid) |
961 | { | |
8d718cbb | 962 | /* DNSKEY RRset determined to be OK, now cache it and the RRsigs that sign it. */ |
e7829aef SK |
963 | cache_start_insert(); |
964 | ||
965 | p = skip_questions(header, plen); | |
966 | ||
967 | for (j = ntohs(header->ancount); j != 0; j--) | |
968 | { | |
969 | /* Ensure we have type, class TTL and length */ | |
970 | if (!(rc = extract_name(header, plen, &p, name, 0, 10))) | |
971 | return STAT_INSECURE; /* bad packet */ | |
972 | ||
973 | GETSHORT(qtype, p); | |
974 | GETSHORT(qclass, p); | |
975 | GETLONG(ttl, p); | |
976 | GETSHORT(rdlen, p); | |
8d718cbb SK |
977 | |
978 | if (!CHECK_LEN(header, p, plen, rdlen)) | |
e7829aef | 979 | return STAT_INSECURE; /* bad packet */ |
e7829aef | 980 | |
8d718cbb | 981 | if (qclass == class && rc == 1) |
e7829aef | 982 | { |
8d718cbb | 983 | psave = p; |
e7829aef | 984 | |
8d718cbb SK |
985 | if (qtype == T_DNSKEY) |
986 | { | |
987 | if (rdlen < 4) | |
988 | return STAT_INSECURE; /* bad packet */ | |
989 | ||
990 | GETSHORT(flags, p); | |
991 | if (*p++ != 3) | |
f01d7be6 | 992 | return STAT_BOGUS; |
8d718cbb SK |
993 | algo = *p++; |
994 | keytag = dnskey_keytag(algo, flags, p, rdlen - 4); | |
995 | ||
996 | /* Cache needs to known class for DNSSEC stuff */ | |
997 | a.addr.dnssec.class = class; | |
998 | ||
999 | if ((key = blockdata_alloc((char*)p, rdlen - 4))) | |
1000 | { | |
1001 | if (!(recp1 = cache_insert(name, &a, now, ttl, F_FORWARD | F_DNSKEY | F_DNSSECOK))) | |
1002 | blockdata_free(key); | |
1003 | else | |
1004 | { | |
1005 | a.addr.keytag = keytag; | |
1006 | log_query(F_KEYTAG | F_UPSTREAM, name, &a, "DNSKEY keytag %u"); | |
1007 | ||
1008 | recp1->addr.key.keylen = rdlen - 4; | |
1009 | recp1->addr.key.keydata = key; | |
1010 | recp1->addr.key.algo = algo; | |
1011 | recp1->addr.key.keytag = keytag; | |
1012 | recp1->addr.key.flags = flags; | |
8d718cbb SK |
1013 | } |
1014 | } | |
1015 | } | |
1016 | else if (qtype == T_RRSIG) | |
1017 | { | |
1018 | /* RRSIG, cache if covers DNSKEY RRset */ | |
1019 | if (rdlen < 18) | |
1020 | return STAT_INSECURE; /* bad packet */ | |
1021 | ||
1022 | GETSHORT(type_covered, p); | |
1023 | ||
1024 | if (type_covered == T_DNSKEY) | |
1025 | { | |
1026 | a.addr.dnssec.class = class; | |
1027 | a.addr.dnssec.type = type_covered; | |
1028 | ||
1029 | algo = *p++; | |
1030 | p += 13; /* labels, orig_ttl, expiration, inception */ | |
1031 | GETSHORT(keytag, p); | |
1032 | if ((key = blockdata_alloc((char*)psave, rdlen))) | |
1033 | { | |
1034 | if (!(crecp = cache_insert(name, &a, now, ttl, F_FORWARD | F_DNSKEY | F_DS))) | |
1035 | blockdata_free(key); | |
1036 | else | |
1037 | { | |
8d718cbb SK |
1038 | crecp->addr.sig.keydata = key; |
1039 | crecp->addr.sig.keylen = rdlen; | |
1040 | crecp->addr.sig.keytag = keytag; | |
1041 | crecp->addr.sig.type_covered = type_covered; | |
1042 | crecp->addr.sig.algo = algo; | |
1043 | } | |
1044 | } | |
1045 | } | |
1046 | } | |
e7829aef | 1047 | |
8d718cbb | 1048 | p = psave; |
e7829aef | 1049 | } |
8d718cbb | 1050 | |
e7829aef SK |
1051 | if (!ADD_RDLEN(header, p, plen, rdlen)) |
1052 | return STAT_INSECURE; /* bad packet */ | |
1053 | } | |
1054 | ||
0fc2f313 SK |
1055 | /* commit cache insert. */ |
1056 | cache_end_insert(); | |
1057 | return STAT_SECURE; | |
1058 | } | |
1059 | ||
1060 | log_query(F_UPSTREAM, name, NULL, "BOGUS DNSKEY"); | |
1061 | return STAT_BOGUS; | |
c3e0b9b6 | 1062 | } |
0fc2f313 | 1063 | |
c3e0b9b6 SK |
1064 | /* The DNS packet is expected to contain the answer to a DS query |
1065 | Put all DSs in the answer which are valid into the cache. | |
1066 | return codes: | |
b8eac191 | 1067 | STAT_INSECURE bad packet, no DS in reply, proven no DS in reply. |
c3e0b9b6 | 1068 | STAT_SECURE At least one valid DS found and in cache. |
00a5b5d4 | 1069 | STAT_NO_DS It's proved there's no DS here. |
c3e0b9b6 SK |
1070 | STAT_BOGUS At least one DS found, which fails validation. |
1071 | STAT_NEED_DNSKEY DNSKEY records to validate a DS not found, name in keyname | |
1072 | */ | |
1073 | ||
1074 | int dnssec_validate_ds(time_t now, struct dns_header *header, size_t plen, char *name, char *keyname, int class) | |
1075 | { | |
51ea3ca2 | 1076 | unsigned char *p = (unsigned char *)(header+1); |
00a5b5d4 | 1077 | int qtype, qclass, val, i, neganswer; |
c3e0b9b6 | 1078 | |
5f8e58f4 | 1079 | if (ntohs(header->qdcount) != 1 || |
b8eac191 | 1080 | !(p = skip_name(p, header, plen, 4))) |
8d718cbb SK |
1081 | return STAT_INSECURE; |
1082 | ||
c3e0b9b6 SK |
1083 | GETSHORT(qtype, p); |
1084 | GETSHORT(qclass, p); | |
1085 | ||
b47b04c8 SK |
1086 | if (qtype != T_DS || qclass != class) |
1087 | val = STAT_BOGUS; | |
1088 | else | |
00a5b5d4 SK |
1089 | val = dnssec_validate_reply(now, header, plen, name, keyname, NULL, &neganswer); |
1090 | ||
1091 | if (val == STAT_NO_SIG) | |
1092 | val = STAT_INSECURE; | |
51ea3ca2 | 1093 | |
b8eac191 SK |
1094 | p = (unsigned char *)(header+1); |
1095 | extract_name(header, plen, &p, name, 1, 4); | |
1096 | p += 4; /* qtype, qclass */ | |
1097 | ||
00a5b5d4 SK |
1098 | if (!(p = skip_section(p, ntohs(header->ancount), header, plen))) |
1099 | return STAT_INSECURE; | |
1100 | ||
0fc2f313 | 1101 | if (val == STAT_BOGUS) |
b8eac191 | 1102 | log_query(F_UPSTREAM, name, NULL, "BOGUS DS"); |
b47b04c8 | 1103 | |
00a5b5d4 | 1104 | if ((val == STAT_SECURE || val == STAT_INSECURE) && neganswer) |
b8eac191 | 1105 | { |
14db4212 | 1106 | int rdlen, flags = F_FORWARD | F_DS | F_NEG; |
b8eac191 SK |
1107 | unsigned long ttl, minttl = ULONG_MAX; |
1108 | struct all_addr a; | |
00a5b5d4 SK |
1109 | |
1110 | if (RCODE(header) == NXDOMAIN) | |
1111 | flags |= F_NXDOMAIN; | |
1112 | ||
1113 | if (val == STAT_SECURE) | |
1114 | flags |= F_DNSSECOK; | |
b8eac191 SK |
1115 | |
1116 | for (i = ntohs(header->nscount); i != 0; i--) | |
1117 | { | |
00a5b5d4 | 1118 | if (!(p = skip_name(p, header, plen, 0))) |
b8eac191 SK |
1119 | return STAT_INSECURE; |
1120 | ||
1121 | GETSHORT(qtype, p); | |
1122 | GETSHORT(qclass, p); | |
1123 | GETLONG(ttl, p); | |
1124 | GETSHORT(rdlen, p); | |
1125 | ||
00a5b5d4 | 1126 | if (!CHECK_LEN(header, p, plen, rdlen)) |
b8eac191 | 1127 | return STAT_INSECURE; /* bad packet */ |
00a5b5d4 SK |
1128 | |
1129 | if (qclass != class || qtype != T_SOA) | |
b8eac191 SK |
1130 | { |
1131 | p += rdlen; | |
1132 | continue; | |
1133 | } | |
1134 | ||
1135 | if (ttl < minttl) | |
1136 | minttl = ttl; | |
1137 | ||
1138 | /* MNAME */ | |
1139 | if (!(p = skip_name(p, header, plen, 0))) | |
1140 | return STAT_INSECURE; | |
1141 | /* RNAME */ | |
1142 | if (!(p = skip_name(p, header, plen, 20))) | |
1143 | return STAT_INSECURE; | |
1144 | p += 16; /* SERIAL REFRESH RETRY EXPIRE */ | |
1145 | ||
1146 | GETLONG(ttl, p); /* minTTL */ | |
1147 | if (ttl < minttl) | |
1148 | minttl = ttl; | |
00a5b5d4 SK |
1149 | |
1150 | break; | |
b8eac191 SK |
1151 | } |
1152 | ||
00a5b5d4 SK |
1153 | if (i != 0) |
1154 | { | |
1155 | cache_start_insert(); | |
1156 | ||
1157 | a.addr.dnssec.class = class; | |
1158 | cache_insert(name, &a, now, ttl, flags); | |
1159 | ||
1160 | cache_end_insert(); | |
1161 | } | |
b8eac191 | 1162 | |
00a5b5d4 | 1163 | return (val == STAT_SECURE) ? STAT_NO_DS : STAT_INSECURE; |
b8eac191 SK |
1164 | } |
1165 | ||
51ea3ca2 | 1166 | return val; |
c3e0b9b6 SK |
1167 | } |
1168 | ||
c5f4ec7d SK |
1169 | /* 4034 6.1 */ |
1170 | static int hostname_cmp(const char *a, const char *b) | |
1171 | { | |
dbf72123 SK |
1172 | char *sa, *ea, *ca, *sb, *eb, *cb; |
1173 | unsigned char ac, bc; | |
1174 | ||
1175 | sa = ea = (char *)a + strlen(a); | |
1176 | sb = eb = (char *)b + strlen(b); | |
1177 | ||
c5f4ec7d SK |
1178 | while (1) |
1179 | { | |
dbf72123 SK |
1180 | while (sa != a && *(sa-1) != '.') |
1181 | sa--; | |
c5f4ec7d | 1182 | |
dbf72123 SK |
1183 | while (sb != b && *(sb-1) != '.') |
1184 | sb--; | |
1185 | ||
1186 | ca = sa; | |
1187 | cb = sb; | |
1188 | ||
1189 | while (1) | |
1190 | { | |
1191 | if (ca == ea) | |
1192 | { | |
1193 | if (cb == eb) | |
1194 | break; | |
1195 | ||
1196 | return -1; | |
1197 | } | |
c5f4ec7d | 1198 | |
dbf72123 SK |
1199 | if (cb == eb) |
1200 | return 1; | |
1201 | ||
1202 | ac = (unsigned char) *ca++; | |
1203 | bc = (unsigned char) *cb++; | |
1204 | ||
1205 | if (ac >= 'A' && ac <= 'Z') | |
1206 | ac += 'a' - 'A'; | |
1207 | if (bc >= 'A' && bc <= 'Z') | |
1208 | bc += 'a' - 'A'; | |
1209 | ||
979cdf9b | 1210 | if (ac < bc) |
dbf72123 SK |
1211 | return -1; |
1212 | else if (ac != bc) | |
1213 | return 1; | |
1214 | } | |
c5f4ec7d | 1215 | |
dbf72123 SK |
1216 | |
1217 | if (sa == a) | |
c5f4ec7d | 1218 | { |
dbf72123 SK |
1219 | if (sb == b) |
1220 | return 0; | |
c5f4ec7d | 1221 | |
dbf72123 | 1222 | return -1; |
c5f4ec7d SK |
1223 | } |
1224 | ||
dbf72123 SK |
1225 | if (sb == b) |
1226 | return 1; | |
c5f4ec7d | 1227 | |
dbf72123 SK |
1228 | ea = sa--; |
1229 | eb = sb--; | |
c5f4ec7d SK |
1230 | } |
1231 | } | |
1232 | ||
5107ace1 SK |
1233 | /* Find all the NSEC or NSEC3 records in a reply. |
1234 | return an array of pointers to them. */ | |
1235 | static int find_nsec_records(struct dns_header *header, size_t plen, unsigned char ***nsecsetp, int *nsecsetl, int class_reqd) | |
1236 | { | |
1237 | static unsigned char **nsecset = NULL; | |
1238 | static int nsecset_sz = 0; | |
1239 | ||
1240 | int type_found = -1; | |
1241 | unsigned char *p = skip_questions(header, plen); | |
1242 | int type, class, rdlen, i, nsecs_found; | |
1243 | ||
1244 | /* Move to NS section */ | |
1245 | if (!p || !(p = skip_section(p, ntohs(header->ancount), header, plen))) | |
1246 | return 0; | |
1247 | ||
1248 | for (nsecs_found = 0, i = ntohs(header->nscount); i != 0; i--) | |
1249 | { | |
1250 | unsigned char *pstart = p; | |
1251 | ||
1252 | if (!(p = skip_name(p, header, plen, 10))) | |
1253 | return 0; | |
1254 | ||
1255 | GETSHORT(type, p); | |
1256 | GETSHORT(class, p); | |
1257 | p += 4; /* TTL */ | |
1258 | GETSHORT(rdlen, p); | |
1259 | ||
1260 | if (class == class_reqd && (type == T_NSEC || type == T_NSEC3)) | |
1261 | { | |
1262 | /* No mixed NSECing 'round here, thankyouverymuch */ | |
1263 | if (type_found == T_NSEC && type == T_NSEC3) | |
1264 | return 0; | |
1265 | if (type_found == T_NSEC3 && type == T_NSEC) | |
1266 | return 0; | |
1267 | ||
1268 | type_found = type; | |
1269 | ||
613ad15d SK |
1270 | if (!expand_workspace(&nsecset, &nsecset_sz, nsecs_found)) |
1271 | return 0; | |
1272 | ||
5107ace1 SK |
1273 | nsecset[nsecs_found++] = pstart; |
1274 | } | |
613ad15d | 1275 | |
5107ace1 SK |
1276 | if (!ADD_RDLEN(header, p, plen, rdlen)) |
1277 | return 0; | |
1278 | } | |
1279 | ||
1280 | *nsecsetp = nsecset; | |
1281 | *nsecsetl = nsecs_found; | |
1282 | ||
1283 | return type_found; | |
1284 | } | |
1285 | ||
24187530 | 1286 | static int prove_non_existence_nsec(struct dns_header *header, size_t plen, unsigned char **nsecs, int nsec_count, |
5107ace1 SK |
1287 | char *workspace1, char *workspace2, char *name, int type) |
1288 | { | |
1289 | int i, rc, rdlen; | |
1290 | unsigned char *p, *psave; | |
1291 | int offset = (type & 0xff) >> 3; | |
1292 | int mask = 0x80 >> (type & 0x07); | |
1293 | ||
1294 | /* Find NSEC record that proves name doesn't exist */ | |
1295 | for (i = 0; i < nsec_count; i++) | |
1296 | { | |
1297 | p = nsecs[i]; | |
1298 | if (!extract_name(header, plen, &p, workspace1, 1, 10)) | |
1299 | return STAT_INSECURE; | |
1300 | p += 8; /* class, type, TTL */ | |
1301 | GETSHORT(rdlen, p); | |
1302 | psave = p; | |
1303 | if (!extract_name(header, plen, &p, workspace2, 1, 10)) | |
1304 | return STAT_INSECURE; | |
1305 | ||
1306 | rc = hostname_cmp(workspace1, name); | |
1307 | ||
1308 | if (rc == 0) | |
1309 | { | |
f01d7be6 SK |
1310 | /* 4035 para 5.4. Last sentence */ |
1311 | if (type == T_NSEC || type == T_RRSIG) | |
1312 | return STAT_SECURE; | |
1313 | ||
5107ace1 SK |
1314 | /* NSEC with the same name as the RR we're testing, check |
1315 | that the type in question doesn't appear in the type map */ | |
1316 | rdlen -= p - psave; | |
1317 | /* rdlen is now length of type map, and p points to it */ | |
1318 | ||
1319 | while (rdlen >= 2) | |
1320 | { | |
1321 | if (!CHECK_LEN(header, p, plen, rdlen)) | |
1322 | return STAT_INSECURE; | |
1323 | ||
1324 | if (p[0] == type >> 8) | |
1325 | { | |
1326 | /* Does the NSEC say our type exists? */ | |
a857daa3 | 1327 | if (offset < p[1] && (p[offset+2] & mask) != 0) |
5107ace1 SK |
1328 | return STAT_BOGUS; |
1329 | ||
1330 | break; /* finshed checking */ | |
1331 | } | |
1332 | ||
1333 | rdlen -= p[1]; | |
1334 | p += p[1]; | |
1335 | } | |
1336 | ||
1337 | return STAT_SECURE; | |
1338 | } | |
1339 | else if (rc == -1) | |
1340 | { | |
1341 | /* Normal case, name falls between NSEC name and next domain name, | |
1342 | wrap around case, name falls between NSEC name (rc == -1) and end */ | |
1343 | if (hostname_cmp(workspace2, name) == 1 || hostname_cmp(workspace1, workspace2) == 1) | |
1344 | return STAT_SECURE; | |
1345 | } | |
1346 | else | |
1347 | { | |
1348 | /* wrap around case, name falls between start and next domain name */ | |
1349 | if (hostname_cmp(workspace1, workspace2) == 1 && hostname_cmp(workspace2, name) == 1) | |
1350 | return STAT_SECURE; | |
1351 | } | |
1352 | } | |
1353 | ||
1354 | return STAT_BOGUS; | |
1355 | } | |
1356 | ||
1357 | /* return digest length, or zero on error */ | |
1358 | static int hash_name(char *in, unsigned char **out, struct nettle_hash const *hash, | |
1359 | unsigned char *salt, int salt_len, int iterations) | |
1360 | { | |
1361 | void *ctx; | |
1362 | unsigned char *digest; | |
1363 | int i; | |
1364 | ||
1365 | if (!hash_init(hash, &ctx, &digest)) | |
1366 | return 0; | |
1367 | ||
1368 | hash->update(ctx, to_wire(in), (unsigned char *)in); | |
1369 | hash->update(ctx, salt_len, salt); | |
1370 | hash->digest(ctx, hash->digest_size, digest); | |
1371 | ||
1372 | for(i = 0; i < iterations; i++) | |
1373 | { | |
1374 | hash->update(ctx, hash->digest_size, digest); | |
1375 | hash->update(ctx, salt_len, salt); | |
1376 | hash->digest(ctx, hash->digest_size, digest); | |
1377 | } | |
1378 | ||
1379 | from_wire(in); | |
1380 | ||
1381 | *out = digest; | |
1382 | return hash->digest_size; | |
1383 | } | |
1384 | ||
1385 | /* Decode base32 to first "." or end of string */ | |
1386 | static int base32_decode(char *in, unsigned char *out) | |
1387 | { | |
a857daa3 | 1388 | int oc, on, c, mask, i; |
5107ace1 SK |
1389 | unsigned char *p = out; |
1390 | ||
a857daa3 | 1391 | for (c = *in, oc = 0, on = 0; c != 0 && c != '.'; c = *++in) |
5107ace1 | 1392 | { |
5107ace1 SK |
1393 | if (c >= '0' && c <= '9') |
1394 | c -= '0'; | |
1395 | else if (c >= 'a' && c <= 'v') | |
1396 | c -= 'a', c += 10; | |
1397 | else if (c >= 'A' && c <= 'V') | |
1398 | c -= 'A', c += 10; | |
1399 | else | |
1400 | return 0; | |
1401 | ||
1402 | for (mask = 0x10, i = 0; i < 5; i++) | |
1403 | { | |
a857daa3 SK |
1404 | if (c & mask) |
1405 | oc |= 1; | |
1406 | mask = mask >> 1; | |
1407 | if (((++on) & 7) == 0) | |
1408 | *p++ = oc; | |
1409 | oc = oc << 1; | |
5107ace1 SK |
1410 | } |
1411 | } | |
1412 | ||
1413 | if ((on & 7) != 0) | |
1414 | return 0; | |
1415 | ||
1416 | return p - out; | |
1417 | } | |
1418 | ||
24187530 | 1419 | static int prove_non_existence_nsec3(struct dns_header *header, size_t plen, unsigned char **nsecs, int nsec_count, |
5107ace1 SK |
1420 | char *workspace1, char *workspace2, char *name, int type) |
1421 | { | |
a857daa3 SK |
1422 | unsigned char *salt, *p, *digest; |
1423 | int digest_len, i, iterations, salt_len, hash_len, base32_len, algo = 0; | |
5107ace1 SK |
1424 | struct nettle_hash const *hash; |
1425 | char *closest_encloser, *next_closest, *wildcard; | |
1426 | ||
1427 | /* Look though the NSEC3 records to find the first one with | |
1428 | an algorithm we support (currently only algo == 1). | |
1429 | ||
1430 | Take the algo, iterations, and salt of that record | |
1431 | as the ones we're going to use, and prune any | |
1432 | that don't match. */ | |
1433 | ||
1434 | for (i = 0; i < nsec_count; i++) | |
1435 | { | |
1436 | if (!(p = skip_name(nsecs[i], header, plen, 15))) | |
1437 | return STAT_INSECURE; /* bad packet */ | |
1438 | ||
1439 | p += 10; /* type, class, TTL, rdlen */ | |
1440 | algo = *p++; | |
1441 | ||
1442 | if (algo == 1) | |
1443 | break; /* known algo */ | |
1444 | } | |
1445 | ||
1446 | /* No usable NSEC3s */ | |
1447 | if (i == nsec_count) | |
1448 | return STAT_BOGUS; | |
1449 | ||
1450 | p++; /* flags */ | |
1451 | GETSHORT (iterations, p); | |
1452 | salt_len = *p++; | |
1453 | salt = p; | |
1454 | if (!CHECK_LEN(header, salt, plen, salt_len)) | |
1455 | return STAT_INSECURE; /* bad packet */ | |
1456 | ||
1457 | /* Now prune so we only have NSEC3 records with same iterations, salt and algo */ | |
1458 | for (i = 0; i < nsec_count; i++) | |
1459 | { | |
1460 | unsigned char *nsec3p = nsecs[i]; | |
1461 | int this_iter; | |
1462 | ||
1463 | nsecs[i] = NULL; /* Speculative, will be restored if OK. */ | |
1464 | ||
1465 | if (!(p = skip_name(nsec3p, header, plen, 15))) | |
1466 | return STAT_INSECURE; /* bad packet */ | |
1467 | ||
1468 | p += 10; /* type, class, TTL, rdlen */ | |
1469 | ||
1470 | if (*p++ != algo) | |
1471 | continue; | |
1472 | ||
1473 | p++; /* flags */ | |
1474 | ||
a857daa3 | 1475 | GETSHORT(this_iter, p); |
5107ace1 SK |
1476 | if (this_iter != iterations) |
1477 | continue; | |
1478 | ||
1479 | if (salt_len != *p++) | |
1480 | continue; | |
1481 | ||
1482 | if (!CHECK_LEN(header, p, plen, salt_len)) | |
1483 | return STAT_INSECURE; /* bad packet */ | |
1484 | ||
1485 | if (memcmp(p, salt, salt_len) != 0) | |
1486 | continue; | |
1487 | ||
1488 | /* All match, put the pointer back */ | |
1489 | nsecs[i] = nsec3p; | |
1490 | } | |
1491 | ||
1492 | /* Algo is checked as 1 above */ | |
1493 | if (!(hash = hash_find("sha1"))) | |
1494 | return STAT_INSECURE; | |
1495 | ||
1496 | /* Now, we need the "closest encloser NSEC3" */ | |
1497 | closest_encloser = name; | |
1498 | next_closest = NULL; | |
1499 | ||
1500 | do | |
1501 | { | |
1502 | if (*closest_encloser == '.') | |
1503 | closest_encloser++; | |
c5f4ec7d | 1504 | |
a857daa3 | 1505 | if ((digest_len = hash_name(closest_encloser, &digest, hash, salt, salt_len, iterations)) == 0) |
5107ace1 SK |
1506 | return STAT_INSECURE; |
1507 | ||
1508 | for (i = 0; i < nsec_count; i++) | |
1509 | if ((p = nsecs[i])) | |
1510 | { | |
5107ace1 | 1511 | if (!extract_name(header, plen, &p, workspace1, 1, 0) || |
a857daa3 | 1512 | !(base32_len = base32_decode(workspace1, (unsigned char *)workspace2))) |
5107ace1 SK |
1513 | return STAT_INSECURE; |
1514 | ||
a857daa3 SK |
1515 | if (digest_len == base32_len && |
1516 | memcmp(digest, workspace2, digest_len) == 0) | |
5107ace1 SK |
1517 | break; /* Gotit */ |
1518 | } | |
1519 | ||
1520 | if (i != nsec_count) | |
1521 | break; | |
1522 | ||
1523 | next_closest = closest_encloser; | |
1524 | } | |
1525 | while ((closest_encloser = strchr(closest_encloser, '.'))); | |
1526 | ||
1527 | /* No usable NSEC3s */ | |
1528 | if (i == nsec_count) | |
1529 | return STAT_BOGUS; | |
1530 | ||
1531 | if (!next_closest) | |
1532 | { | |
1533 | /* We found an NSEC3 whose hashed name exactly matches the query, so | |
1534 | Now we just need to check the type map. p points to the RR data for the record. */ | |
a857daa3 | 1535 | int rdlen; |
5107ace1 SK |
1536 | unsigned char *psave; |
1537 | int offset = (type & 0xff) >> 3; | |
1538 | int mask = 0x80 >> (type & 0x07); | |
1539 | ||
1540 | p += 8; /* class, type, TTL */ | |
1541 | GETSHORT(rdlen, p); | |
1542 | psave = p; | |
1543 | p += 5 + salt_len; /* algo, flags, iterations, salt_len, salt */ | |
1544 | hash_len = *p++; | |
1545 | if (!CHECK_LEN(header, p, plen, hash_len)) | |
1546 | return STAT_INSECURE; /* bad packet */ | |
1547 | p += hash_len; | |
1548 | rdlen -= p - psave; | |
1549 | ||
1550 | while (rdlen >= 2) | |
1551 | { | |
1552 | if (!CHECK_LEN(header, p, plen, rdlen)) | |
1553 | return STAT_INSECURE; | |
1554 | ||
1555 | if (p[0] == type >> 8) | |
1556 | { | |
a857daa3 SK |
1557 | /* Does the NSEC3 say our type exists? */ |
1558 | if (offset < p[1] && (p[offset+2] & mask) != 0) | |
5107ace1 SK |
1559 | return STAT_BOGUS; |
1560 | ||
1561 | break; /* finshed checking */ | |
1562 | } | |
1563 | ||
1564 | rdlen -= p[1]; | |
1565 | p += p[1]; | |
1566 | } | |
1567 | ||
1568 | return STAT_SECURE; | |
1569 | } | |
1570 | ||
24187530 | 1571 | /* Look for NSEC3 that proves the non-existence of the next-closest encloser */ |
a857daa3 | 1572 | if ((digest_len = hash_name(next_closest, &digest, hash, salt, salt_len, iterations)) == 0) |
5107ace1 SK |
1573 | return STAT_INSECURE; |
1574 | ||
1575 | for (i = 0; i < nsec_count; i++) | |
1576 | if ((p = nsecs[i])) | |
1577 | { | |
a857daa3 SK |
1578 | if (!extract_name(header, plen, &p, workspace1, 1, 0) || |
1579 | !(base32_len = base32_decode(workspace1, (unsigned char *)workspace2))) | |
5107ace1 SK |
1580 | return STAT_INSECURE; |
1581 | ||
1582 | p += 15 + salt_len; /* class, type, TTL, rdlen, algo, flags, iterations, salt_len, salt */ | |
1583 | hash_len = *p++; /* p now points to next hashed name */ | |
1584 | ||
1585 | if (!CHECK_LEN(header, p, plen, hash_len)) | |
1586 | return STAT_INSECURE; | |
1587 | ||
a857daa3 | 1588 | if (digest_len == base32_len && hash_len == base32_len) |
5107ace1 | 1589 | { |
a857daa3 | 1590 | if (memcmp(workspace2, digest, digest_len) <= 0) |
5107ace1 SK |
1591 | { |
1592 | /* Normal case, hash falls between NSEC3 name-hash and next domain name-hash, | |
1593 | wrap around case, name-hash falls between NSEC3 name-hash and end */ | |
a857daa3 | 1594 | if (memcmp(p, digest, digest_len) > 0 || memcmp(workspace2, p, digest_len) > 0) |
5107ace1 SK |
1595 | return STAT_SECURE; |
1596 | } | |
1597 | else | |
1598 | { | |
1599 | /* wrap around case, name falls between start and next domain name */ | |
a857daa3 | 1600 | if (memcmp(workspace2, p, digest_len) > 0 && memcmp(p, digest, digest_len) > 0) |
5107ace1 SK |
1601 | return STAT_SECURE; |
1602 | } | |
1603 | } | |
1604 | } | |
1605 | ||
1606 | /* Finally, check that there's no seat of wildcard synthesis */ | |
1607 | if (!(wildcard = strchr(next_closest, '.')) || wildcard == next_closest) | |
1608 | return STAT_BOGUS; | |
1609 | ||
1610 | wildcard--; | |
1611 | *wildcard = '*'; | |
1612 | ||
a857daa3 | 1613 | if ((digest_len = hash_name(wildcard, &digest, hash, salt, salt_len, iterations)) == 0) |
5107ace1 SK |
1614 | return STAT_INSECURE; |
1615 | ||
1616 | for (i = 0; i < nsec_count; i++) | |
1617 | if ((p = nsecs[i])) | |
1618 | { | |
5107ace1 | 1619 | if (!extract_name(header, plen, &p, workspace1, 1, 0) || |
a857daa3 | 1620 | !(base32_len = base32_decode(workspace1, (unsigned char *)workspace2))) |
5107ace1 SK |
1621 | return STAT_INSECURE; |
1622 | ||
1623 | p += 15 + salt_len; /* class, type, TTL, rdlen, algo, flags, iterations, salt_len, salt */ | |
1624 | hash_len = *p++; /* p now points to next hashed name */ | |
1625 | ||
1626 | if (!CHECK_LEN(header, p, plen, hash_len)) | |
1627 | return STAT_INSECURE; | |
1628 | ||
a857daa3 | 1629 | if (digest_len == base32_len && hash_len == base32_len) |
5107ace1 | 1630 | { |
a857daa3 | 1631 | if (memcmp(workspace2, digest, digest_len) <= 0) |
5107ace1 SK |
1632 | { |
1633 | /* Normal case, hash falls between NSEC3 name-hash and next domain name-hash, | |
1634 | wrap around case, name-hash falls between NSEC3 name-hash and end */ | |
a857daa3 | 1635 | if (memcmp(p, digest, digest_len) > 0 || memcmp(workspace2, p, digest_len) > 0) |
5107ace1 SK |
1636 | return STAT_SECURE; |
1637 | } | |
1638 | else | |
1639 | { | |
1640 | /* wrap around case, name falls between start and next domain name */ | |
a857daa3 | 1641 | if (memcmp(workspace2, p, digest_len) > 0 && memcmp(p, digest, digest_len) > 0) |
5107ace1 SK |
1642 | return STAT_SECURE; |
1643 | } | |
1644 | } | |
1645 | } | |
1646 | ||
1647 | return STAT_BOGUS; | |
1648 | } | |
1649 | ||
0fc2f313 | 1650 | /* Validate all the RRsets in the answer and authority sections of the reply (4035:3.2.3) */ |
51ea3ca2 | 1651 | /* Returns are the same as validate_rrset, plus the class if the missing key is in *class */ |
00a5b5d4 | 1652 | int dnssec_validate_reply(time_t now, struct dns_header *header, size_t plen, char *name, char *keyname, int *class, int *neganswer) |
adca3e9c | 1653 | { |
00a5b5d4 SK |
1654 | unsigned char *ans_start, *qname, *p1, *p2, **nsecs; |
1655 | int type1, class1, rdlen1, type2, class2, rdlen2, qclass, qtype; | |
5107ace1 | 1656 | int i, j, rc, nsec_count, cname_count = 10; |
00a5b5d4 | 1657 | int nsec_type = 0, have_answer = 0; |
adca3e9c | 1658 | |
00a5b5d4 SK |
1659 | if (neganswer) |
1660 | *neganswer = 0; | |
1661 | ||
e3ec15af SK |
1662 | if (RCODE(header) == SERVFAIL) |
1663 | return STAT_BOGUS; | |
1664 | ||
c5f4ec7d | 1665 | if ((RCODE(header) != NXDOMAIN && RCODE(header) != NOERROR) || ntohs(header->qdcount) != 1) |
72ae2f3d | 1666 | return STAT_INSECURE; |
00a5b5d4 SK |
1667 | |
1668 | qname = p1 = (unsigned char *)(header+1); | |
c5f4ec7d | 1669 | |
00a5b5d4 SK |
1670 | if (!extract_name(header, plen, &p1, name, 1, 4)) |
1671 | return STAT_INSECURE; | |
1672 | ||
1673 | GETSHORT(qtype, p1); | |
1674 | GETSHORT(qclass, p1); | |
1675 | ans_start = p1; | |
1676 | ||
1677 | /* Can't validate an RRISG query */ | |
1678 | if (qtype == T_RRSIG) | |
0fc2f313 | 1679 | return STAT_INSECURE; |
00a5b5d4 SK |
1680 | |
1681 | cname_loop: | |
1682 | for (j = ntohs(header->ancount); j != 0; j--) | |
1683 | { | |
1684 | /* leave pointer to missing name in qname */ | |
1685 | ||
1686 | if (!(rc = extract_name(header, plen, &p1, name, 0, 10))) | |
1687 | return STAT_INSECURE; /* bad packet */ | |
1688 | ||
1689 | GETSHORT(type2, p1); | |
1690 | GETSHORT(class2, p1); | |
1691 | p1 += 4; /* TTL */ | |
1692 | GETSHORT(rdlen2, p1); | |
1693 | ||
1694 | if (rc == 1 && qclass == class2) | |
1695 | { | |
1696 | /* Do we have an answer for the question? */ | |
1697 | if (type2 == qtype) | |
1698 | { | |
1699 | have_answer = 1; | |
1700 | break; | |
1701 | } | |
1702 | else if (type2 == T_CNAME) | |
1703 | { | |
1704 | qname = p1; | |
1705 | ||
1706 | /* looped CNAMES */ | |
1707 | if (!cname_count-- || !extract_name(header, plen, &p1, name, 1, 0)) | |
1708 | return STAT_INSECURE; | |
1709 | ||
1710 | p1 = ans_start; | |
1711 | goto cname_loop; | |
1712 | } | |
1713 | } | |
1714 | ||
1715 | if (!ADD_RDLEN(header, p1, plen, rdlen2)) | |
1716 | return STAT_INSECURE; | |
1717 | } | |
0fc2f313 | 1718 | |
00a5b5d4 SK |
1719 | if (neganswer && !have_answer) |
1720 | *neganswer = 1; | |
0575610f SK |
1721 | |
1722 | /* No data, therefore no sigs */ | |
1723 | if (ntohs(header->ancount) + ntohs(header->nscount) == 0) | |
1724 | return STAT_NO_SIG; | |
00a5b5d4 | 1725 | |
0fc2f313 | 1726 | for (p1 = ans_start, i = 0; i < ntohs(header->ancount) + ntohs(header->nscount); i++) |
adca3e9c | 1727 | { |
0fc2f313 SK |
1728 | if (!extract_name(header, plen, &p1, name, 1, 10)) |
1729 | return STAT_INSECURE; /* bad packet */ | |
1730 | ||
1731 | GETSHORT(type1, p1); | |
1732 | GETSHORT(class1, p1); | |
1733 | p1 += 4; /* TTL */ | |
1734 | GETSHORT(rdlen1, p1); | |
1735 | ||
1736 | /* Don't try and validate RRSIGs! */ | |
1737 | if (type1 != T_RRSIG) | |
1738 | { | |
1739 | /* Check if we've done this RRset already */ | |
1740 | for (p2 = ans_start, j = 0; j < i; j++) | |
1741 | { | |
1742 | if (!(rc = extract_name(header, plen, &p2, name, 0, 10))) | |
1743 | return STAT_INSECURE; /* bad packet */ | |
1744 | ||
1745 | GETSHORT(type2, p2); | |
1746 | GETSHORT(class2, p2); | |
1747 | p2 += 4; /* TTL */ | |
1748 | GETSHORT(rdlen2, p2); | |
1749 | ||
1750 | if (type2 == type1 && class2 == class1 && rc == 1) | |
1751 | break; /* Done it before: name, type, class all match. */ | |
1752 | ||
1753 | if (!ADD_RDLEN(header, p2, plen, rdlen2)) | |
1754 | return STAT_INSECURE; | |
1755 | } | |
1756 | ||
1757 | /* Not done, validate now */ | |
51ea3ca2 | 1758 | if (j == i) |
0fc2f313 | 1759 | { |
8d718cbb SK |
1760 | int ttl, keytag, algo, digest, type_covered; |
1761 | unsigned char *psave; | |
1762 | struct all_addr a; | |
1763 | struct blockdata *key; | |
1764 | struct crec *crecp; | |
1765 | ||
5107ace1 SK |
1766 | rc = validate_rrset(now, header, plen, class1, type1, name, keyname, NULL, 0, 0, 0); |
1767 | ||
1768 | if (rc == STAT_SECURE_WILDCARD) | |
1769 | { | |
1770 | /* An attacker replay a wildcard answer with a different | |
a857daa3 | 1771 | answer and overlay a genuine RR. To prove this |
5107ace1 | 1772 | hasn't happened, the answer must prove that |
a857daa3 | 1773 | the gennuine record doesn't exist. Check that here. */ |
5107ace1 SK |
1774 | if (!nsec_type) |
1775 | { | |
1776 | nsec_type = find_nsec_records(header, plen, &nsecs, &nsec_count, class1); | |
1777 | ||
1778 | if (nsec_type == 0) | |
1779 | return STAT_INSECURE; /* Bad packet */ | |
1780 | if (nsec_type == -1) | |
1781 | return STAT_BOGUS; /* No NSECs */ | |
1782 | } | |
1783 | ||
1784 | if (nsec_type == T_NSEC) | |
24187530 | 1785 | rc = prove_non_existence_nsec(header, plen, nsecs, nsec_count, daemon->workspacename, keyname, name, type1); |
5107ace1 | 1786 | else |
24187530 | 1787 | rc = prove_non_existence_nsec3(header, plen, nsecs, nsec_count, daemon->workspacename, keyname, name, type1); |
5107ace1 SK |
1788 | |
1789 | if (rc != STAT_SECURE) | |
1790 | return rc; | |
1791 | } | |
1792 | else if (rc != STAT_SECURE) | |
51ea3ca2 SK |
1793 | { |
1794 | if (class) | |
1795 | *class = class1; /* Class for DS or DNSKEY */ | |
1796 | return rc; | |
1797 | } | |
5107ace1 | 1798 | |
8d718cbb SK |
1799 | /* Cache RRsigs in answer section, and if we just validated a DS RRset, cache it */ |
1800 | cache_start_insert(); | |
1801 | ||
1802 | for (p2 = ans_start, j = 0; j < ntohs(header->ancount); j++) | |
51ea3ca2 | 1803 | { |
8d718cbb SK |
1804 | if (!(rc = extract_name(header, plen, &p2, name, 0, 10))) |
1805 | return STAT_INSECURE; /* bad packet */ | |
51ea3ca2 | 1806 | |
8d718cbb SK |
1807 | GETSHORT(type2, p2); |
1808 | GETSHORT(class2, p2); | |
1809 | GETLONG(ttl, p2); | |
1810 | GETSHORT(rdlen2, p2); | |
1811 | ||
1812 | if (!CHECK_LEN(header, p2, plen, rdlen2)) | |
1813 | return STAT_INSECURE; /* bad packet */ | |
1814 | ||
1815 | if (class2 == class1 && rc == 1) | |
1816 | { | |
1817 | psave = p2; | |
1818 | ||
1819 | if (type1 == T_DS && type2 == T_DS) | |
51ea3ca2 | 1820 | { |
8d718cbb SK |
1821 | if (rdlen2 < 4) |
1822 | return STAT_INSECURE; /* bad packet */ | |
1823 | ||
51ea3ca2 SK |
1824 | GETSHORT(keytag, p2); |
1825 | algo = *p2++; | |
1826 | digest = *p2++; | |
1827 | ||
1828 | /* Cache needs to known class for DNSSEC stuff */ | |
1829 | a.addr.dnssec.class = class2; | |
1830 | ||
8d718cbb | 1831 | if ((key = blockdata_alloc((char*)p2, rdlen2 - 4))) |
51ea3ca2 | 1832 | { |
8d718cbb SK |
1833 | if (!(crecp = cache_insert(name, &a, now, ttl, F_FORWARD | F_DS | F_DNSSECOK))) |
1834 | blockdata_free(key); | |
1835 | else | |
1836 | { | |
1837 | a.addr.keytag = keytag; | |
1838 | log_query(F_KEYTAG | F_UPSTREAM, name, &a, "DS keytag %u"); | |
1839 | crecp->addr.ds.digest = digest; | |
1840 | crecp->addr.ds.keydata = key; | |
1841 | crecp->addr.ds.algo = algo; | |
1842 | crecp->addr.ds.keytag = keytag; | |
8d718cbb SK |
1843 | crecp->addr.ds.keylen = rdlen2 - 4; |
1844 | } | |
1845 | } | |
1846 | } | |
1847 | else if (type2 == T_RRSIG) | |
1848 | { | |
1849 | if (rdlen2 < 18) | |
1850 | return STAT_INSECURE; /* bad packet */ | |
51ea3ca2 | 1851 | |
8d718cbb SK |
1852 | GETSHORT(type_covered, p2); |
1853 | ||
1854 | if (type_covered == type1 && | |
1855 | (type_covered == T_A || type_covered == T_AAAA || | |
1856 | type_covered == T_CNAME || type_covered == T_DS || | |
1857 | type_covered == T_DNSKEY || type_covered == T_PTR)) | |
1858 | { | |
1859 | a.addr.dnssec.type = type_covered; | |
c8ca33f8 | 1860 | a.addr.dnssec.class = class1; |
8d718cbb SK |
1861 | |
1862 | algo = *p2++; | |
1863 | p2 += 13; /* labels, orig_ttl, expiration, inception */ | |
1864 | GETSHORT(keytag, p2); | |
1865 | ||
1866 | if ((key = blockdata_alloc((char*)psave, rdlen2))) | |
1867 | { | |
1868 | if (!(crecp = cache_insert(name, &a, now, ttl, F_FORWARD | F_DNSKEY | F_DS))) | |
1869 | blockdata_free(key); | |
1870 | else | |
1871 | { | |
8d718cbb SK |
1872 | crecp->addr.sig.keydata = key; |
1873 | crecp->addr.sig.keylen = rdlen2; | |
1874 | crecp->addr.sig.keytag = keytag; | |
1875 | crecp->addr.sig.type_covered = type_covered; | |
1876 | crecp->addr.sig.algo = algo; | |
1877 | } | |
1878 | } | |
1879 | } | |
51ea3ca2 SK |
1880 | } |
1881 | ||
8d718cbb | 1882 | p2 = psave; |
51ea3ca2 SK |
1883 | } |
1884 | ||
8d718cbb SK |
1885 | if (!ADD_RDLEN(header, p2, plen, rdlen2)) |
1886 | return STAT_INSECURE; /* bad packet */ | |
51ea3ca2 | 1887 | } |
8d718cbb SK |
1888 | |
1889 | cache_end_insert(); | |
0fc2f313 SK |
1890 | } |
1891 | } | |
adca3e9c | 1892 | |
0fc2f313 SK |
1893 | if (!ADD_RDLEN(header, p1, plen, rdlen1)) |
1894 | return STAT_INSECURE; | |
adca3e9c GB |
1895 | } |
1896 | ||
c5f4ec7d | 1897 | /* OK, all the RRsets validate, now see if we have a NODATA or NXDOMAIN reply */ |
00a5b5d4 SK |
1898 | if (have_answer) |
1899 | return STAT_SECURE; | |
1900 | ||
5107ace1 | 1901 | /* NXDOMAIN or NODATA reply, prove that (name, class1, type1) can't exist */ |
5107ace1 SK |
1902 | /* First marshall the NSEC records, if we've not done it previously */ |
1903 | if (!nsec_type) | |
c5f4ec7d | 1904 | { |
00a5b5d4 | 1905 | nsec_type = find_nsec_records(header, plen, &nsecs, &nsec_count, qclass); |
c5f4ec7d | 1906 | |
5107ace1 SK |
1907 | if (nsec_type == 0) |
1908 | return STAT_INSECURE; /* Bad packet */ | |
1909 | if (nsec_type == -1) | |
1910 | return STAT_BOGUS; /* No NSECs */ | |
c5f4ec7d | 1911 | } |
00a5b5d4 SK |
1912 | |
1913 | /* Get name of missing answer */ | |
1914 | if (!extract_name(header, plen, &qname, name, 1, 0)) | |
1915 | return STAT_INSECURE; | |
5107ace1 SK |
1916 | |
1917 | if (nsec_type == T_NSEC) | |
00a5b5d4 | 1918 | return prove_non_existence_nsec(header, plen, nsecs, nsec_count, daemon->workspacename, keyname, name, qtype); |
5107ace1 | 1919 | else |
00a5b5d4 | 1920 | return prove_non_existence_nsec3(header, plen, nsecs, nsec_count, daemon->workspacename, keyname, name, qtype); |
e292e93d GB |
1921 | } |
1922 | ||
00a5b5d4 SK |
1923 | /* Chase the CNAME chain in the packet until the first record which _doesn't validate. |
1924 | Needed for proving answer in unsigned space. | |
1925 | Return STAT_NEED_* | |
1926 | STAT_BOGUS - error | |
1927 | STAT_INSECURE - name of first non-secure record in name | |
1928 | */ | |
1929 | int dnssec_chase_cname(time_t now, struct dns_header *header, size_t plen, char *name, char *keyname) | |
1930 | { | |
1931 | unsigned char *p = (unsigned char *)(header+1); | |
1932 | int type, class, qtype, qclass, rdlen, j, rc; | |
1933 | int cname_count = 10; | |
1934 | ||
1935 | /* Get question */ | |
1936 | if (!extract_name(header, plen, &p, name, 1, 4)) | |
1937 | return STAT_BOGUS; | |
1938 | ||
1939 | GETSHORT(qtype, p); | |
1940 | GETSHORT(qclass, p); | |
1941 | ||
1942 | while (1) | |
1943 | { | |
1944 | for (j = ntohs(header->ancount); j != 0; j--) | |
1945 | { | |
1946 | if (!(rc = extract_name(header, plen, &p, name, 0, 10))) | |
1947 | return STAT_BOGUS; /* bad packet */ | |
1948 | ||
1949 | GETSHORT(type, p); | |
1950 | GETSHORT(class, p); | |
1951 | p += 4; /* TTL */ | |
1952 | GETSHORT(rdlen, p); | |
1953 | ||
1954 | /* Not target, loop */ | |
1955 | if (rc == 2 || qclass != class) | |
1956 | { | |
1957 | if (!ADD_RDLEN(header, p, plen, rdlen)) | |
1958 | return STAT_BOGUS; | |
1959 | continue; | |
1960 | } | |
1961 | ||
1962 | /* Got to end of CNAME chain. */ | |
1963 | if (type != T_CNAME) | |
1964 | return STAT_INSECURE; | |
1965 | ||
1966 | /* validate CNAME chain, return if insecure or need more data */ | |
1967 | rc = validate_rrset(now, header, plen, class, type, name, keyname, NULL, 0, 0, 0); | |
1968 | if (rc != STAT_SECURE) | |
1969 | { | |
1970 | if (rc == STAT_NO_SIG) | |
1971 | rc = STAT_INSECURE; | |
1972 | return rc; | |
1973 | } | |
1974 | ||
1975 | /* Loop down CNAME chain/ */ | |
1976 | if (!cname_count-- || | |
1977 | !extract_name(header, plen, &p, name, 1, 0) || | |
1978 | !(p = skip_questions(header, plen))) | |
1979 | return STAT_BOGUS; | |
1980 | ||
1981 | break; | |
1982 | } | |
1983 | ||
1984 | /* End of CNAME chain */ | |
1985 | return STAT_INSECURE; | |
1986 | } | |
1987 | } | |
1988 | ||
1989 | ||
3471f181 | 1990 | /* Compute keytag (checksum to quickly index a key). See RFC4034 */ |
0fc2f313 | 1991 | int dnskey_keytag(int alg, int flags, unsigned char *key, int keylen) |
3471f181 | 1992 | { |
75ffc9bf GB |
1993 | if (alg == 1) |
1994 | { | |
1995 | /* Algorithm 1 (RSAMD5) has a different (older) keytag calculation algorithm. | |
1996 | See RFC4034, Appendix B.1 */ | |
0fc2f313 | 1997 | return key[keylen-4] * 256 + key[keylen-3]; |
75ffc9bf GB |
1998 | } |
1999 | else | |
2000 | { | |
1633e308 | 2001 | unsigned long ac = flags + 0x300 + alg; |
75ffc9bf GB |
2002 | int i; |
2003 | ||
0fc2f313 SK |
2004 | for (i = 0; i < keylen; ++i) |
2005 | ac += (i & 1) ? key[i] : key[i] << 8; | |
1633e308 | 2006 | |
0fc2f313 SK |
2007 | ac += (ac >> 16) & 0xffff; |
2008 | return ac & 0xffff; | |
0304d28f | 2009 | } |
3471f181 | 2010 | } |
e292e93d | 2011 | |
5f8e58f4 SK |
2012 | size_t dnssec_generate_query(struct dns_header *header, char *end, char *name, int class, int type, union mysockaddr *addr) |
2013 | { | |
2014 | unsigned char *p; | |
610e782a | 2015 | char *types = querystr("dnssec-query", type); |
5f8e58f4 SK |
2016 | |
2017 | if (addr->sa.sa_family == AF_INET) | |
2018 | log_query(F_DNSSEC | F_IPV4, name, (struct all_addr *)&addr->in.sin_addr, types); | |
2019 | #ifdef HAVE_IPV6 | |
2020 | else | |
2021 | log_query(F_DNSSEC | F_IPV6, name, (struct all_addr *)&addr->in6.sin6_addr, types); | |
2022 | #endif | |
2023 | ||
2024 | header->qdcount = htons(1); | |
2025 | header->ancount = htons(0); | |
2026 | header->nscount = htons(0); | |
2027 | header->arcount = htons(0); | |
e292e93d | 2028 | |
5f8e58f4 SK |
2029 | header->hb3 = HB3_RD; |
2030 | SET_OPCODE(header, QUERY); | |
5b3bf921 SK |
2031 | /* For debugging, set Checking Disabled, otherwise, have the upstream check too, |
2032 | this allows it to select auth servers when one is returning bad data. */ | |
2033 | header->hb4 = option_bool(OPT_DNSSEC_DEBUG) ? HB4_CD : 0; | |
5f8e58f4 SK |
2034 | |
2035 | /* ID filled in later */ | |
2036 | ||
2037 | p = (unsigned char *)(header+1); | |
2038 | ||
2039 | p = do_rfc1035_name(p, name); | |
2040 | *p++ = 0; | |
2041 | PUTSHORT(type, p); | |
2042 | PUTSHORT(class, p); | |
2043 | ||
2044 | return add_do_bit(header, p - (unsigned char *)header, end); | |
2045 | } | |
8a9be9e4 | 2046 | |
613ad15d SK |
2047 | /* Go through a domain name, find "pointers" and fix them up based on how many bytes |
2048 | we've chopped out of the packet, or check they don't point into an elided part. */ | |
2049 | static int check_name(unsigned char **namep, struct dns_header *header, size_t plen, int fixup, unsigned char **rrs, int rr_count) | |
2050 | { | |
2051 | unsigned char *ansp = *namep; | |
2052 | ||
2053 | while(1) | |
2054 | { | |
2055 | unsigned int label_type; | |
2056 | ||
2057 | if (!CHECK_LEN(header, ansp, plen, 1)) | |
2058 | return 0; | |
2059 | ||
2060 | label_type = (*ansp) & 0xc0; | |
2061 | ||
2062 | if (label_type == 0xc0) | |
2063 | { | |
2064 | /* pointer for compression. */ | |
00a5b5d4 SK |
2065 | unsigned int offset; |
2066 | int i; | |
613ad15d SK |
2067 | unsigned char *p; |
2068 | ||
2069 | if (!CHECK_LEN(header, ansp, plen, 2)) | |
2070 | return 0; | |
2071 | ||
2072 | offset = ((*ansp++) & 0x3f) << 8; | |
2073 | offset |= *ansp++; | |
2074 | ||
2075 | p = offset + (unsigned char *)header; | |
2076 | ||
2077 | for (i = 0; i < rr_count; i++) | |
2078 | if (p < rrs[i]) | |
2079 | break; | |
2080 | else | |
2081 | if (i & 1) | |
2082 | offset -= rrs[i] - rrs[i-1]; | |
2083 | ||
2084 | /* does the pointer end up in an elided RR? */ | |
2085 | if (i & 1) | |
00a5b5d4 | 2086 | return 0; |
613ad15d SK |
2087 | |
2088 | /* No, scale the pointer */ | |
2089 | if (fixup) | |
2090 | { | |
2091 | ansp -= 2; | |
2092 | *ansp++ = (offset >> 8) | 0xc0; | |
2093 | *ansp++ = offset & 0xff; | |
2094 | } | |
2095 | break; | |
2096 | } | |
2097 | else if (label_type == 0x80) | |
2098 | return 0; /* reserved */ | |
2099 | else if (label_type == 0x40) | |
2100 | { | |
2101 | /* Extended label type */ | |
2102 | unsigned int count; | |
2103 | ||
2104 | if (!CHECK_LEN(header, ansp, plen, 2)) | |
2105 | return 0; | |
2106 | ||
2107 | if (((*ansp++) & 0x3f) != 1) | |
2108 | return 0; /* we only understand bitstrings */ | |
2109 | ||
2110 | count = *(ansp++); /* Bits in bitstring */ | |
2111 | ||
2112 | if (count == 0) /* count == 0 means 256 bits */ | |
2113 | ansp += 32; | |
2114 | else | |
2115 | ansp += ((count-1)>>3)+1; | |
2116 | } | |
2117 | else | |
2118 | { /* label type == 0 Bottom six bits is length */ | |
2119 | unsigned int len = (*ansp++) & 0x3f; | |
2120 | ||
2121 | if (!ADD_RDLEN(header, ansp, plen, len)) | |
2122 | return 0; | |
2123 | ||
2124 | if (len == 0) | |
2125 | break; /* zero length label marks the end. */ | |
2126 | } | |
2127 | } | |
2128 | ||
2129 | *namep = ansp; | |
2130 | ||
2131 | return 1; | |
2132 | } | |
2133 | ||
2134 | /* Go through RRs and check or fixup the domain names contained within */ | |
2135 | static int check_rrs(unsigned char *p, struct dns_header *header, size_t plen, int fixup, unsigned char **rrs, int rr_count) | |
2136 | { | |
2137 | int i, type, class, rdlen; | |
00a5b5d4 | 2138 | unsigned char *pp; |
613ad15d SK |
2139 | |
2140 | for (i = 0; i < ntohs(header->ancount) + ntohs(header->nscount); i++) | |
2141 | { | |
00a5b5d4 SK |
2142 | pp = p; |
2143 | ||
2144 | if (!(p = skip_name(p, header, plen, 10))) | |
2145 | return 0; | |
613ad15d SK |
2146 | |
2147 | GETSHORT(type, p); | |
2148 | GETSHORT(class, p); | |
2149 | p += 4; /* TTL */ | |
2150 | GETSHORT(rdlen, p); | |
00a5b5d4 | 2151 | |
613ad15d SK |
2152 | if (type != T_NSEC && type != T_NSEC3 && type != T_RRSIG) |
2153 | { | |
00a5b5d4 SK |
2154 | /* fixup name of RR */ |
2155 | if (!check_name(&pp, header, plen, fixup, rrs, rr_count)) | |
2156 | return 0; | |
2157 | ||
613ad15d SK |
2158 | if (class == C_IN) |
2159 | { | |
2160 | u16 *d; | |
14db4212 SK |
2161 | |
2162 | for (pp = p, d = get_desc(type); *d != (u16)-1; d++) | |
613ad15d SK |
2163 | { |
2164 | if (*d != 0) | |
2165 | pp += *d; | |
2166 | else if (!check_name(&pp, header, plen, fixup, rrs, rr_count)) | |
2167 | return 0; | |
2168 | } | |
2169 | } | |
2170 | } | |
2171 | ||
2172 | if (!ADD_RDLEN(header, p, plen, rdlen)) | |
2173 | return 0; | |
2174 | } | |
2175 | ||
2176 | return 1; | |
2177 | } | |
2178 | ||
2179 | ||
2180 | size_t filter_rrsigs(struct dns_header *header, size_t plen) | |
2181 | { | |
2182 | static unsigned char **rrs; | |
2183 | static int rr_sz = 0; | |
2184 | ||
2185 | unsigned char *p = (unsigned char *)(header+1); | |
2186 | int i, rdlen, qtype, qclass, rr_found, chop_an, chop_ns; | |
2187 | ||
2188 | if (ntohs(header->qdcount) != 1 || | |
2189 | !(p = skip_name(p, header, plen, 4))) | |
2190 | return plen; | |
2191 | ||
2192 | GETSHORT(qtype, p); | |
2193 | GETSHORT(qclass, p); | |
2194 | ||
2195 | /* First pass, find pointers to start and end of all the records we wish to elide: | |
2196 | records added for DNSSEC, unless explicity queried for */ | |
2197 | for (rr_found = 0, chop_ns = 0, chop_an = 0, i = 0; i < ntohs(header->ancount) + ntohs(header->nscount); i++) | |
2198 | { | |
2199 | unsigned char *pstart = p; | |
2200 | int type, class; | |
2201 | ||
2202 | if (!(p = skip_name(p, header, plen, 10))) | |
2203 | return plen; | |
2204 | ||
2205 | GETSHORT(type, p); | |
2206 | GETSHORT(class, p); | |
2207 | p += 4; /* TTL */ | |
2208 | GETSHORT(rdlen, p); | |
2209 | ||
2210 | if ((type == T_NSEC || type == T_NSEC3 || type == T_RRSIG) && | |
2211 | (type != qtype || class != qclass)) | |
2212 | { | |
2213 | if (!expand_workspace(&rrs, &rr_sz, rr_found + 1)) | |
2214 | return plen; | |
2215 | ||
2216 | rrs[rr_found++] = pstart; | |
2217 | ||
2218 | if (!ADD_RDLEN(header, p, plen, rdlen)) | |
2219 | return plen; | |
2220 | ||
2221 | rrs[rr_found++] = p; | |
2222 | ||
2223 | if (i < ntohs(header->ancount)) | |
2224 | chop_an++; | |
2225 | else | |
2226 | chop_ns++; | |
2227 | } | |
2228 | else if (!ADD_RDLEN(header, p, plen, rdlen)) | |
2229 | return plen; | |
2230 | } | |
2231 | ||
2232 | /* Nothing to do. */ | |
2233 | if (rr_found == 0) | |
2234 | return plen; | |
2235 | ||
2236 | /* Second pass, look for pointers in names in the records we're keeping and make sure they don't | |
2237 | point to records we're going to elide. This is theoretically possible, but unlikely. If | |
2238 | it happens, we give up and leave the answer unchanged. */ | |
2239 | p = (unsigned char *)(header+1); | |
2240 | ||
2241 | /* question first */ | |
2242 | if (!check_name(&p, header, plen, 0, rrs, rr_found)) | |
2243 | return plen; | |
2244 | p += 4; /* qclass, qtype */ | |
2245 | ||
2246 | /* Now answers and NS */ | |
2247 | if (!check_rrs(p, header, plen, 0, rrs, rr_found)) | |
2248 | return plen; | |
2249 | ||
2250 | /* Third pass, elide records */ | |
2251 | for (p = rrs[0], i = 1; i < rr_found; i += 2) | |
2252 | { | |
2253 | unsigned char *start = rrs[i]; | |
2254 | unsigned char *end = (i != rr_found - 1) ? rrs[i+1] : ((unsigned char *)(header+1)) + plen; | |
2255 | ||
2256 | memmove(p, start, end-start); | |
2257 | p += end-start; | |
2258 | } | |
2259 | ||
2260 | plen = p - (unsigned char *)header; | |
2261 | header->ancount = htons(ntohs(header->ancount) - chop_an); | |
2262 | header->nscount = htons(ntohs(header->nscount) - chop_ns); | |
2263 | ||
2264 | /* Fourth pass, fix up pointers in the remaining records */ | |
2265 | p = (unsigned char *)(header+1); | |
2266 | ||
2267 | check_name(&p, header, plen, 1, rrs, rr_found); | |
2268 | p += 4; /* qclass, qtype */ | |
2269 | ||
2270 | check_rrs(p, header, plen, 1, rrs, rr_found); | |
2271 | ||
2272 | return plen; | |
2273 | } | |
2274 | ||
8a9be9e4 SK |
2275 | unsigned char* hash_questions(struct dns_header *header, size_t plen, char *name) |
2276 | { | |
2277 | int q; | |
2278 | unsigned int len; | |
2279 | unsigned char *p = (unsigned char *)(header+1); | |
2280 | const struct nettle_hash *hash; | |
2281 | void *ctx; | |
2282 | unsigned char *digest; | |
5f8e58f4 | 2283 | |
8a9be9e4 SK |
2284 | if (!(hash = hash_find("sha1")) || !hash_init(hash, &ctx, &digest)) |
2285 | return NULL; | |
2286 | ||
2287 | for (q = ntohs(header->qdcount); q != 0; q--) | |
2288 | { | |
2289 | if (!extract_name(header, plen, &p, name, 1, 4)) | |
7d23a66f | 2290 | break; /* bad packet */ |
8a9be9e4 SK |
2291 | |
2292 | len = to_wire(name); | |
2293 | hash->update(ctx, len, (unsigned char *)name); | |
2294 | /* CRC the class and type as well */ | |
2295 | hash->update(ctx, 4, p); | |
2296 | ||
2297 | p += 4; | |
2298 | if (!CHECK_LEN(header, p, plen, 0)) | |
7d23a66f | 2299 | break; /* bad packet */ |
8a9be9e4 | 2300 | } |
703c7ff4 SK |
2301 | |
2302 | hash->digest(ctx, hash->digest_size, digest); | |
8a9be9e4 SK |
2303 | return digest; |
2304 | } | |
2305 | ||
0fc2f313 | 2306 | #endif /* HAVE_DNSSEC */ |