1 /* $OpenBSD: getrrsetbyname.c,v 1.11 2007/10/11 18:36:41 jakob Exp $ */
2
3 /*
4 * Copyright (c) 2001 Jakob Schlyter. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 /*
30 * Portions Copyright (c) 1999-2001 Internet Software Consortium.
31 *
32 * Permission to use, copy, modify, and distribute this software for any
33 * purpose with or without fee is hereby granted, provided that the above
34 * copyright notice and this permission notice appear in all copies.
35 *
36 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM
37 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
38 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
39 * INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
40 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
41 * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
42 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
43 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
44 */
45
46 /* OPENBSD ORIGINAL: lib/libc/net/getrrsetbyname.c */
47
48 #include "includes.h"
49
50 #ifndef HAVE_GETRRSETBYNAME
51
52 #include <stdlib.h>
53 #include <string.h>
54
55 #include <netinet/in.h>
56 #include <arpa/inet.h>
57
58 #include "getrrsetbyname.h"
59 #include "nameser.h"
60 #include "nameser_compat.h"
61
62 #if defined(HAVE_DECL_H_ERRNO) && !HAVE_DECL_H_ERRNO
63 extern int h_errno;
64 #endif
65
66 /* We don't need multithread support here */
67 #ifdef _THREAD_PRIVATE
68 # undef _THREAD_PRIVATE
69 #endif
70 #define _THREAD_PRIVATE(a,b,c) (c)
71
72 #ifndef HAVE__RES_EXTERN
73 struct __res_state _res;
74 #endif
75
76 /* Necessary functions and macros */
77
78 /*
79 * Inline versions of get/put short/long. Pointer is advanced.
80 *
81 * These macros demonstrate the property of C whereby it can be
82 * portable or it can be elegant but rarely both.
83 */
84
85 #ifndef INT32SZ
86 # define INT32SZ 4
87 #endif
88 #ifndef INT16SZ
89 # define INT16SZ 2
90 #endif
91
92 #ifndef GETSHORT
93 #define GETSHORT(s, cp) { \
94 register u_char *t_cp = (u_char *)(cp); \
95 (s) = ((u_int16_t)t_cp[0] << 8) \
96 | ((u_int16_t)t_cp[1]) \
97 ; \
98 (cp) += INT16SZ; \
99 }
100 #endif
101
102 #ifndef GETLONG
103 #define GETLONG(l, cp) { \
104 register u_char *t_cp = (u_char *)(cp); \
105 (l) = ((u_int32_t)t_cp[0] << 24) \
106 | ((u_int32_t)t_cp[1] << 16) \
107 | ((u_int32_t)t_cp[2] << 8) \
108 | ((u_int32_t)t_cp[3]) \
109 ; \
110 (cp) += INT32SZ; \
111 }
112 #endif
113
114 /*
115 * Routines to insert/extract short/long's.
116 */
117
118 #ifndef HAVE__GETSHORT
119 static u_int16_t
_getshort(msgp)120 _getshort(msgp)
121 register const u_char *msgp;
122 {
123 register u_int16_t u;
124
125 GETSHORT(u, msgp);
126 return (u);
127 }
128 #elif defined(HAVE_DECL__GETSHORT) && (HAVE_DECL__GETSHORT == 0)
129 u_int16_t _getshort(register const u_char *);
130 #endif
131
132 #ifndef HAVE__GETLONG
133 static u_int32_t
_getlong(msgp)134 _getlong(msgp)
135 register const u_char *msgp;
136 {
137 register u_int32_t u;
138
139 GETLONG(u, msgp);
140 return (u);
141 }
142 #elif defined(HAVE_DECL__GETLONG) && (HAVE_DECL__GETLONG == 0)
143 u_int32_t _getlong(register const u_char *);
144 #endif
145
146 /* ************** */
147
148 #define ANSWER_BUFFER_SIZE 0xffff
149
150 struct dns_query {
151 char *name;
152 u_int16_t type;
153 u_int16_t class;
154 struct dns_query *next;
155 };
156
157 struct dns_rr {
158 char *name;
159 u_int16_t type;
160 u_int16_t class;
161 u_int16_t ttl;
162 u_int16_t size;
163 void *rdata;
164 struct dns_rr *next;
165 };
166
167 struct dns_response {
168 HEADER header;
169 struct dns_query *query;
170 struct dns_rr *answer;
171 struct dns_rr *authority;
172 struct dns_rr *additional;
173 };
174
175 static struct dns_response *parse_dns_response(const u_char *, int);
176 static struct dns_query *parse_dns_qsection(const u_char *, int,
177 const u_char **, int);
178 static struct dns_rr *parse_dns_rrsection(const u_char *, int, const u_char **,
179 int);
180
181 static void free_dns_query(struct dns_query *);
182 static void free_dns_rr(struct dns_rr *);
183 static void free_dns_response(struct dns_response *);
184
185 static int count_dns_rr(struct dns_rr *, u_int16_t, u_int16_t);
186
187 int
getrrsetbyname(const char * hostname,unsigned int rdclass,unsigned int rdtype,unsigned int flags,struct rrsetinfo ** res)188 getrrsetbyname(const char *hostname, unsigned int rdclass,
189 unsigned int rdtype, unsigned int flags,
190 struct rrsetinfo **res)
191 {
192 struct __res_state *_resp = _THREAD_PRIVATE(_res, _res, &_res);
193 int result;
194 struct rrsetinfo *rrset = NULL;
195 struct dns_response *response = NULL;
196 struct dns_rr *rr;
197 struct rdatainfo *rdata;
198 int length;
199 unsigned int index_ans, index_sig;
200 u_char answer[ANSWER_BUFFER_SIZE];
201
202 /* check for invalid class and type */
203 if (rdclass > 0xffff || rdtype > 0xffff) {
204 result = ERRSET_INVAL;
205 goto fail;
206 }
207
208 /* don't allow queries of class or type ANY */
209 if (rdclass == 0xff || rdtype == 0xff) {
210 result = ERRSET_INVAL;
211 goto fail;
212 }
213
214 /* don't allow flags yet, unimplemented */
215 if (flags) {
216 result = ERRSET_INVAL;
217 goto fail;
218 }
219
220 /* initialize resolver */
221 if ((_resp->options & RES_INIT) == 0 && res_init() == -1) {
222 result = ERRSET_FAIL;
223 goto fail;
224 }
225
226 #ifdef DEBUG
227 _resp->options |= RES_DEBUG;
228 #endif /* DEBUG */
229
230 #ifdef RES_USE_DNSSEC
231 /* turn on DNSSEC if EDNS0 is configured */
232 if (_resp->options & RES_USE_EDNS0)
233 _resp->options |= RES_USE_DNSSEC;
234 #endif /* RES_USE_DNSEC */
235
236 /* make query */
237 length = res_query(hostname, (signed int) rdclass, (signed int) rdtype,
238 answer, sizeof(answer));
239 if (length < 0) {
240 switch(h_errno) {
241 case HOST_NOT_FOUND:
242 result = ERRSET_NONAME;
243 goto fail;
244 case NO_DATA:
245 result = ERRSET_NODATA;
246 goto fail;
247 default:
248 result = ERRSET_FAIL;
249 goto fail;
250 }
251 }
252
253 /* parse result */
254 response = parse_dns_response(answer, length);
255 if (response == NULL) {
256 result = ERRSET_FAIL;
257 goto fail;
258 }
259
260 if (response->header.qdcount != 1) {
261 result = ERRSET_FAIL;
262 goto fail;
263 }
264
265 /* initialize rrset */
266 rrset = calloc(1, sizeof(struct rrsetinfo));
267 if (rrset == NULL) {
268 result = ERRSET_NOMEMORY;
269 goto fail;
270 }
271 rrset->rri_rdclass = response->query->class;
272 rrset->rri_rdtype = response->query->type;
273 rrset->rri_ttl = response->answer->ttl;
274 rrset->rri_nrdatas = response->header.ancount;
275
276 #ifdef HAVE_HEADER_AD
277 /* check for authenticated data */
278 if (response->header.ad == 1)
279 rrset->rri_flags |= RRSET_VALIDATED;
280 #endif
281
282 /* copy name from answer section */
283 rrset->rri_name = strdup(response->answer->name);
284 if (rrset->rri_name == NULL) {
285 result = ERRSET_NOMEMORY;
286 goto fail;
287 }
288
289 /* count answers */
290 rrset->rri_nrdatas = count_dns_rr(response->answer, rrset->rri_rdclass,
291 rrset->rri_rdtype);
292 rrset->rri_nsigs = count_dns_rr(response->answer, rrset->rri_rdclass,
293 T_RRSIG);
294
295 /* allocate memory for answers */
296 rrset->rri_rdatas = calloc(rrset->rri_nrdatas,
297 sizeof(struct rdatainfo));
298 if (rrset->rri_rdatas == NULL) {
299 result = ERRSET_NOMEMORY;
300 goto fail;
301 }
302
303 /* allocate memory for signatures */
304 if (rrset->rri_nsigs > 0) {
305 rrset->rri_sigs = calloc(rrset->rri_nsigs, sizeof(struct rdatainfo));
306 if (rrset->rri_sigs == NULL) {
307 result = ERRSET_NOMEMORY;
308 goto fail;
309 }
310 }
311
312 /* copy answers & signatures */
313 for (rr = response->answer, index_ans = 0, index_sig = 0;
314 rr; rr = rr->next) {
315
316 rdata = NULL;
317
318 if (rr->class == rrset->rri_rdclass &&
319 rr->type == rrset->rri_rdtype)
320 rdata = &rrset->rri_rdatas[index_ans++];
321
322 if (rr->class == rrset->rri_rdclass &&
323 rr->type == T_RRSIG)
324 rdata = &rrset->rri_sigs[index_sig++];
325
326 if (rdata) {
327 rdata->rdi_length = rr->size;
328 rdata->rdi_data = malloc(rr->size);
329
330 if (rdata->rdi_data == NULL) {
331 result = ERRSET_NOMEMORY;
332 goto fail;
333 }
334 memcpy(rdata->rdi_data, rr->rdata, rr->size);
335 }
336 }
337 free_dns_response(response);
338
339 *res = rrset;
340 return (ERRSET_SUCCESS);
341
342 fail:
343 if (rrset != NULL)
344 freerrset(rrset);
345 if (response != NULL)
346 free_dns_response(response);
347 return (result);
348 }
349
350 void
freerrset(struct rrsetinfo * rrset)351 freerrset(struct rrsetinfo *rrset)
352 {
353 u_int16_t i;
354
355 if (rrset == NULL)
356 return;
357
358 if (rrset->rri_rdatas) {
359 for (i = 0; i < rrset->rri_nrdatas; i++) {
360 if (rrset->rri_rdatas[i].rdi_data == NULL)
361 break;
362 free(rrset->rri_rdatas[i].rdi_data);
363 }
364 free(rrset->rri_rdatas);
365 }
366
367 if (rrset->rri_sigs) {
368 for (i = 0; i < rrset->rri_nsigs; i++) {
369 if (rrset->rri_sigs[i].rdi_data == NULL)
370 break;
371 free(rrset->rri_sigs[i].rdi_data);
372 }
373 free(rrset->rri_sigs);
374 }
375
376 if (rrset->rri_name)
377 free(rrset->rri_name);
378 free(rrset);
379 }
380
381 /*
382 * DNS response parsing routines
383 */
384 static struct dns_response *
parse_dns_response(const u_char * answer,int size)385 parse_dns_response(const u_char *answer, int size)
386 {
387 struct dns_response *resp;
388 const u_char *cp;
389
390 /* allocate memory for the response */
391 resp = calloc(1, sizeof(*resp));
392 if (resp == NULL)
393 return (NULL);
394
395 /* initialize current pointer */
396 cp = answer;
397
398 /* copy header */
399 memcpy(&resp->header, cp, HFIXEDSZ);
400 cp += HFIXEDSZ;
401
402 /* fix header byte order */
403 resp->header.qdcount = ntohs(resp->header.qdcount);
404 resp->header.ancount = ntohs(resp->header.ancount);
405 resp->header.nscount = ntohs(resp->header.nscount);
406 resp->header.arcount = ntohs(resp->header.arcount);
407
408 /* there must be at least one query */
409 if (resp->header.qdcount < 1) {
410 free_dns_response(resp);
411 return (NULL);
412 }
413
414 /* parse query section */
415 resp->query = parse_dns_qsection(answer, size, &cp,
416 resp->header.qdcount);
417 if (resp->header.qdcount && resp->query == NULL) {
418 free_dns_response(resp);
419 return (NULL);
420 }
421
422 /* parse answer section */
423 resp->answer = parse_dns_rrsection(answer, size, &cp,
424 resp->header.ancount);
425 if (resp->header.ancount && resp->answer == NULL) {
426 free_dns_response(resp);
427 return (NULL);
428 }
429
430 /* parse authority section */
431 resp->authority = parse_dns_rrsection(answer, size, &cp,
432 resp->header.nscount);
433 if (resp->header.nscount && resp->authority == NULL) {
434 free_dns_response(resp);
435 return (NULL);
436 }
437
438 /* parse additional section */
439 resp->additional = parse_dns_rrsection(answer, size, &cp,
440 resp->header.arcount);
441 if (resp->header.arcount && resp->additional == NULL) {
442 free_dns_response(resp);
443 return (NULL);
444 }
445
446 return (resp);
447 }
448
449 static struct dns_query *
parse_dns_qsection(const u_char * answer,int size,const u_char ** cp,int count)450 parse_dns_qsection(const u_char *answer, int size, const u_char **cp, int count)
451 {
452 struct dns_query *head, *curr, *prev;
453 int i, length;
454 char name[MAXDNAME];
455
456 for (i = 1, head = NULL, prev = NULL; i <= count; i++, prev = curr) {
457
458 /* allocate and initialize struct */
459 curr = calloc(1, sizeof(struct dns_query));
460 if (curr == NULL) {
461 free_dns_query(head);
462 return (NULL);
463 }
464 if (head == NULL)
465 head = curr;
466 if (prev != NULL)
467 prev->next = curr;
468
469 /* name */
470 length = dn_expand(answer, answer + size, *cp, name,
471 sizeof(name));
472 if (length < 0) {
473 free_dns_query(head);
474 return (NULL);
475 }
476 curr->name = strdup(name);
477 if (curr->name == NULL) {
478 free_dns_query(head);
479 return (NULL);
480 }
481 *cp += length;
482
483 /* type */
484 curr->type = _getshort(*cp);
485 *cp += INT16SZ;
486
487 /* class */
488 curr->class = _getshort(*cp);
489 *cp += INT16SZ;
490 }
491
492 return (head);
493 }
494
495 static struct dns_rr *
parse_dns_rrsection(const u_char * answer,int size,const u_char ** cp,int count)496 parse_dns_rrsection(const u_char *answer, int size, const u_char **cp,
497 int count)
498 {
499 struct dns_rr *head, *curr, *prev;
500 int i, length;
501 char name[MAXDNAME];
502
503 for (i = 1, head = NULL, prev = NULL; i <= count; i++, prev = curr) {
504
505 /* allocate and initialize struct */
506 curr = calloc(1, sizeof(struct dns_rr));
507 if (curr == NULL) {
508 free_dns_rr(head);
509 return (NULL);
510 }
511 if (head == NULL)
512 head = curr;
513 if (prev != NULL)
514 prev->next = curr;
515
516 /* name */
517 length = dn_expand(answer, answer + size, *cp, name,
518 sizeof(name));
519 if (length < 0) {
520 free_dns_rr(head);
521 return (NULL);
522 }
523 curr->name = strdup(name);
524 if (curr->name == NULL) {
525 free_dns_rr(head);
526 return (NULL);
527 }
528 *cp += length;
529
530 /* type */
531 curr->type = _getshort(*cp);
532 *cp += INT16SZ;
533
534 /* class */
535 curr->class = _getshort(*cp);
536 *cp += INT16SZ;
537
538 /* ttl */
539 curr->ttl = _getlong(*cp);
540 *cp += INT32SZ;
541
542 /* rdata size */
543 curr->size = _getshort(*cp);
544 *cp += INT16SZ;
545
546 /* rdata itself */
547 curr->rdata = malloc(curr->size);
548 if (curr->rdata == NULL) {
549 free_dns_rr(head);
550 return (NULL);
551 }
552 memcpy(curr->rdata, *cp, curr->size);
553 *cp += curr->size;
554 }
555
556 return (head);
557 }
558
559 static void
free_dns_query(struct dns_query * p)560 free_dns_query(struct dns_query *p)
561 {
562 if (p == NULL)
563 return;
564
565 if (p->name)
566 free(p->name);
567 free_dns_query(p->next);
568 free(p);
569 }
570
571 static void
free_dns_rr(struct dns_rr * p)572 free_dns_rr(struct dns_rr *p)
573 {
574 if (p == NULL)
575 return;
576
577 if (p->name)
578 free(p->name);
579 if (p->rdata)
580 free(p->rdata);
581 free_dns_rr(p->next);
582 free(p);
583 }
584
585 static void
free_dns_response(struct dns_response * p)586 free_dns_response(struct dns_response *p)
587 {
588 if (p == NULL)
589 return;
590
591 free_dns_query(p->query);
592 free_dns_rr(p->answer);
593 free_dns_rr(p->authority);
594 free_dns_rr(p->additional);
595 free(p);
596 }
597
598 static int
count_dns_rr(struct dns_rr * p,u_int16_t class,u_int16_t type)599 count_dns_rr(struct dns_rr *p, u_int16_t class, u_int16_t type)
600 {
601 int n = 0;
602
603 while(p) {
604 if (p->class == class && p->type == type)
605 n++;
606 p = p->next;
607 }
608
609 return (n);
610 }
611
612 #endif /* !defined(HAVE_GETRRSETBYNAME) */
613