]> git.ipfire.org Git - thirdparty/systemd.git/blame - src/resolve/resolved-dns-packet.c
projects / thirdparty / systemd.git / blame
? search:
summary | shortlog | log | commit | commitdiff | tree
blob | blame (incremental) | history | HEAD
resolved: add alignment to base64
[thirdparty/systemd.git] / src / resolve / resolved-dns-packet.c
CommitLineData
74b2466e
LP		 1/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
2
3/***
4 This file is part of systemd.
5
6 Copyright 2014 Lennart Poettering
7
8 systemd is free software; you can redistribute it and/or modify it
9 under the terms of the GNU Lesser General Public License as published by
10 the Free Software Foundation; either version 2.1 of the License, or
11 (at your option) any later version.
12
13 systemd is distributed in the hope that it will be useful, but
14 WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 Lesser General Public License for more details.
17
18 You should have received a copy of the GNU Lesser General Public License
19 along with systemd; If not, see <http://www.gnu.org/licenses/>.
20 ***/
21
b5efdb8a 22#include "alloc-util.h"
4ad7f276 23#include "dns-domain.h"
74b2466e 24#include "resolved-dns-packet.h"
8b43440b
LP		 25#include "string-table.h"
26#include "strv.h"
27#include "unaligned.h"
28#include "utf8.h"
29#include "util.h"
74b2466e 30
7586f4d1
TG		 31#define EDNS0_OPT_DO (1<<15)
32
1716f6dc 33int dns_packet_new(DnsPacket **ret, DnsProtocol protocol, size_t mtu) {
74b2466e
LP		 34 DnsPacket *p;
35 size_t a;
36
37 assert(ret);
38
a0166609 39 if (mtu <= UDP_PACKET_HEADER_SIZE)
74b2466e
LP		 40 a = DNS_PACKET_SIZE_START;
41 else
a0166609 42 a = mtu - UDP_PACKET_HEADER_SIZE;
74b2466e
LP		 43
44 if (a < DNS_PACKET_HEADER_SIZE)
45 a = DNS_PACKET_HEADER_SIZE;
46
c73ce96b
LP		 47 /* round up to next page size */
48 a = PAGE_ALIGN(ALIGN(sizeof(DnsPacket)) + a) - ALIGN(sizeof(DnsPacket));
49
50 /* make sure we never allocate more than useful */
51 if (a > DNS_PACKET_SIZE_MAX)
52 a = DNS_PACKET_SIZE_MAX;
53
74b2466e
LP		 54 p = malloc0(ALIGN(sizeof(DnsPacket)) + a);
55 if (!p)
56 return -ENOMEM;
57
58 p->size = p->rindex = DNS_PACKET_HEADER_SIZE;
59 p->allocated = a;
1716f6dc 60 p->protocol = protocol;
519ef046 61 p->opt_start = p->opt_size = (size_t) -1;
74b2466e
LP		 62 p->n_ref = 1;
63
64 *ret = p;
65
66 return 0;
67}
68
dbfbb6e7 69void dns_packet_set_flags(DnsPacket *p, bool dnssec_checking_disabled, bool truncated) {
74b2466e 70
dbfbb6e7 71 DnsPacketHeader *h;
74b2466e 72
dbfbb6e7 73 assert(p);
74b2466e
LP		 74
75 h = DNS_PACKET_HEADER(p);
1716f6dc 76
dbfbb6e7
DM		 77 switch(p->protocol) {
78 case DNS_PROTOCOL_LLMNR:
79 assert(!truncated);
80
069360a6
LP		 81 h->flags = htobe16(DNS_PACKET_MAKE_FLAGS(0 /* qr */,
82 0 /* opcode */,
83 0 /* c */,
e5abebab 84 0 /* tc */,
069360a6
LP		 85 0 /* t */,
86 0 /* ra */,
87 0 /* ad */,
88 0 /* cd */,
89 0 /* rcode */));
dbfbb6e7
DM		 90 break;
91
92 case DNS_PROTOCOL_MDNS:
93 h->flags = htobe16(DNS_PACKET_MAKE_FLAGS(0 /* qr */,
94 0 /* opcode */,
95 0 /* aa */,
96 truncated /* tc */,
97 0 /* rd (ask for recursion) */,
98 0 /* ra */,
99 0 /* ad */,
100 0 /* cd */,
101 0 /* rcode */));
102 break;
103
104 default:
105 assert(!truncated);
106
069360a6
LP		 107 h->flags = htobe16(DNS_PACKET_MAKE_FLAGS(0 /* qr */,
108 0 /* opcode */,
109 0 /* aa */,
110 0 /* tc */,
111 1 /* rd (ask for recursion) */,
112 0 /* ra */,
113 0 /* ad */,
24710c48 114 dnssec_checking_disabled /* cd */,
069360a6 115 0 /* rcode */));
dbfbb6e7
DM		 116 }
117}
118
119int dns_packet_new_query(DnsPacket **ret, DnsProtocol protocol, size_t mtu, bool dnssec_checking_disabled) {
120 DnsPacket *p;
121 int r;
122
123 assert(ret);
124
125 r = dns_packet_new(&p, protocol, mtu);
126 if (r < 0)
127 return r;
128
129 /* Always set the TC bit to 0 initially.
130 * If there are multiple packets later, we'll update the bit shortly before sending.
131 */
132 dns_packet_set_flags(p, dnssec_checking_disabled, false);
74b2466e
LP		 133
134 *ret = p;
135 return 0;
136}
137
138DnsPacket *dns_packet_ref(DnsPacket *p) {
139
140 if (!p)
141 return NULL;
142
a8812dd7
LP		 143 assert(!p->on_stack);
144
74b2466e
LP		 145 assert(p->n_ref > 0);
146 p->n_ref++;
147 return p;
148}
149
150static void dns_packet_free(DnsPacket *p) {
151 char *s;
152
153 assert(p);
154
faa133f3
LP		 155 dns_question_unref(p->question);
156 dns_answer_unref(p->answer);
d75acfb0 157 dns_resource_record_unref(p->opt);
322345fd 158
74b2466e
LP		 159 while ((s = hashmap_steal_first_key(p->names)))
160 free(s);
161 hashmap_free(p->names);
162
faa133f3 163 free(p->_data);
a8812dd7
LP		 164
165 if (!p->on_stack)
166 free(p);
74b2466e
LP		 167}
168
169DnsPacket *dns_packet_unref(DnsPacket *p) {
170 if (!p)
171 return NULL;
172
173 assert(p->n_ref > 0);
174
6728a58d 175 dns_packet_unref(p->more);
9c491563 176
74b2466e
LP		 177 if (p->n_ref == 1)
178 dns_packet_free(p);
179 else
180 p->n_ref--;
181
182 return NULL;
183}
184
185int dns_packet_validate(DnsPacket *p) {
186 assert(p);
187
188 if (p->size < DNS_PACKET_HEADER_SIZE)
189 return -EBADMSG;
190
c73ce96b
LP		 191 if (p->size > DNS_PACKET_SIZE_MAX)
192 return -EBADMSG;
193
623a4c97 194 return 1;
74b2466e
LP		 195}
196
197int dns_packet_validate_reply(DnsPacket *p) {
74b2466e
LP		 198 int r;
199
200 assert(p);
201
202 r = dns_packet_validate(p);
203 if (r < 0)
204 return r;
205
623a4c97
LP		 206 if (DNS_PACKET_QR(p) != 1)
207 return 0;
208
209 if (DNS_PACKET_OPCODE(p) != 0)
74b2466e
LP		 210 return -EBADMSG;
211
818ef443 212 switch (p->protocol) {
d75acfb0 213
818ef443
DM		 214 case DNS_PROTOCOL_LLMNR:
215 /* RFC 4795, Section 2.1.1. says to discard all replies with QDCOUNT != 1 */
216 if (DNS_PACKET_QDCOUNT(p) != 1)
217 return -EBADMSG;
218
219 break;
220
4e5bf5e1
DM		 221 case DNS_PROTOCOL_MDNS:
222 /* RFC 6762, Section 18 */
223 if (DNS_PACKET_RCODE(p) != 0)
224 return -EBADMSG;
225
226 break;
227
818ef443
DM		 228 default:
229 break;
230 }
ea917db9 231
623a4c97
LP		 232 return 1;
233}
234
235int dns_packet_validate_query(DnsPacket *p) {
236 int r;
237
238 assert(p);
239
240 r = dns_packet_validate(p);
241 if (r < 0)
242 return r;
243
244 if (DNS_PACKET_QR(p) != 0)
245 return 0;
246
3cb10d3a 247 if (DNS_PACKET_OPCODE(p) != 0)
74b2466e
LP		 248 return -EBADMSG;
249
623a4c97
LP		 250 if (DNS_PACKET_TC(p))
251 return -EBADMSG;
252
818ef443 253 switch (p->protocol) {
d75acfb0 254
818ef443
DM		 255 case DNS_PROTOCOL_LLMNR:
256 /* RFC 4795, Section 2.1.1. says to discard all queries with QDCOUNT != 1 */
257 if (DNS_PACKET_QDCOUNT(p) != 1)
258 return -EBADMSG;
623a4c97 259
818ef443
DM		 260 /* RFC 4795, Section 2.1.1. says to discard all queries with ANCOUNT != 0 */
261 if (DNS_PACKET_ANCOUNT(p) > 0)
262 return -EBADMSG;
623a4c97 263
818ef443
DM		 264 /* RFC 4795, Section 2.1.1. says to discard all queries with NSCOUNT != 0 */
265 if (DNS_PACKET_NSCOUNT(p) > 0)
266 return -EBADMSG;
267
268 break;
269
4e5bf5e1
DM		 270 case DNS_PROTOCOL_MDNS:
271 /* RFC 6762, Section 18 */
272 if (DNS_PACKET_AA(p) != 0 ||
273 DNS_PACKET_RD(p) != 0 ||
274 DNS_PACKET_RA(p) != 0 ||
275 DNS_PACKET_AD(p) != 0 ||
276 DNS_PACKET_CD(p) != 0 ||
277 DNS_PACKET_RCODE(p) != 0)
278 return -EBADMSG;
279
280 break;
281
818ef443
DM		 282 default:
283 break;
284 }
623a4c97
LP		 285
286 return 1;
74b2466e
LP		 287}
288
289static int dns_packet_extend(DnsPacket *p, size_t add, void **ret, size_t *start) {
290 assert(p);
291
c73ce96b
LP		 292 if (p->size + add > p->allocated) {
293 size_t a;
294
295 a = PAGE_ALIGN((p->size + add) * 2);
296 if (a > DNS_PACKET_SIZE_MAX)
297 a = DNS_PACKET_SIZE_MAX;
298
299 if (p->size + add > a)
300 return -EMSGSIZE;
301
faa133f3 302 if (p->_data) {
c73ce96b
LP		 303 void *d;
304
faa133f3 305 d = realloc(p->_data, a);
c73ce96b
LP		 306 if (!d)
307 return -ENOMEM;
308
faa133f3 309 p->_data = d;
c73ce96b 310 } else {
faa133f3
LP		 311 p->_data = malloc(a);
312 if (!p->_data)
c73ce96b
LP		 313 return -ENOMEM;
314
faa133f3
LP		 315 memcpy(p->_data, (uint8_t*) p + ALIGN(sizeof(DnsPacket)), p->size);
316 memzero((uint8_t*) p->_data + p->size, a - p->size);
c73ce96b
LP		 317 }
318
319 p->allocated = a;
320 }
74b2466e
LP		 321
322 if (start)
323 *start = p->size;
324
325 if (ret)
326 *ret = (uint8_t*) DNS_PACKET_DATA(p) + p->size;
327
328 p->size += add;
329 return 0;
330}
331
9c5e12a4 332void dns_packet_truncate(DnsPacket *p, size_t sz) {
74b2466e
LP		 333 Iterator i;
334 char *s;
335 void *n;
336
337 assert(p);
338
339 if (p->size <= sz)
340 return;
341
0e03ade5 342 HASHMAP_FOREACH_KEY(n, s, p->names, i) {
74b2466e
LP		 343
344 if (PTR_TO_SIZE(n) < sz)
345 continue;
346
347 hashmap_remove(p->names, s);
348 free(s);
349 }
350
351 p->size = sz;
352}
353
623a4c97
LP		 354int dns_packet_append_blob(DnsPacket *p, const void *d, size_t l, size_t *start) {
355 void *q;
356 int r;
357
358 assert(p);
359
360 r = dns_packet_extend(p, l, &q, start);
361 if (r < 0)
362 return r;
363
364 memcpy(q, d, l);
365 return 0;
366}
367
74b2466e
LP		 368int dns_packet_append_uint8(DnsPacket *p, uint8_t v, size_t *start) {
369 void *d;
370 int r;
371
372 assert(p);
373
374 r = dns_packet_extend(p, sizeof(uint8_t), &d, start);
375 if (r < 0)
376 return r;
377
378 ((uint8_t*) d)[0] = v;
379
380 return 0;
381}
382
383int dns_packet_append_uint16(DnsPacket *p, uint16_t v, size_t *start) {
384 void *d;
385 int r;
386
387 assert(p);
388
389 r = dns_packet_extend(p, sizeof(uint16_t), &d, start);
390 if (r < 0)
391 return r;
392
725ca0e5 393 unaligned_write_be16(d, v);
623a4c97
LP		 394
395 return 0;
396}
397
398int dns_packet_append_uint32(DnsPacket *p, uint32_t v, size_t *start) {
399 void *d;
400 int r;
401
402 assert(p);
403
404 r = dns_packet_extend(p, sizeof(uint32_t), &d, start);
405 if (r < 0)
406 return r;
407
725ca0e5 408 unaligned_write_be32(d, v);
74b2466e
LP		 409
410 return 0;
411}
412
413int dns_packet_append_string(DnsPacket *p, const char *s, size_t *start) {
74b2466e
LP		 414 assert(p);
415 assert(s);
416
c38a52da 417 return dns_packet_append_raw_string(p, s, strlen(s), start);
74b2466e
LP		 418}
419
2001c805
LP		 420int dns_packet_append_raw_string(DnsPacket *p, const void *s, size_t size, size_t *start) {
421 void *d;
422 int r;
423
424 assert(p);
425 assert(s || size == 0);
426
427 if (size > 255)
428 return -E2BIG;
429
430 r = dns_packet_extend(p, 1 + size, &d, start);
431 if (r < 0)
432 return r;
433
434 ((uint8_t*) d)[0] = (uint8_t) size;
435
436 if (size > 0)
437 memcpy(((uint8_t*) d) + 1, s, size);
438
439 return 0;
440}
441
a3db237b 442int dns_packet_append_label(DnsPacket *p, const char *d, size_t l, bool canonical_candidate, size_t *start) {
a8812dd7 443 uint8_t *w;
74b2466e
LP		 444 int r;
445
a3db237b
LP		 446 /* Append a label to a packet. Optionally, does this in DNSSEC
447 * canonical form, if this label is marked as a candidate for
448 * it, and the canonical form logic is enabled for the
449 * packet */
450
74b2466e
LP		 451 assert(p);
452 assert(d);
453
454 if (l > DNS_LABEL_MAX)
455 return -E2BIG;
456
a8812dd7 457 r = dns_packet_extend(p, 1 + l, (void**) &w, start);
74b2466e
LP		 458 if (r < 0)
459 return r;
460
a8812dd7
LP		 461 *(w++) = (uint8_t) l;
462
a3db237b 463 if (p->canonical_form && canonical_candidate) {
a8812dd7
LP		 464 size_t i;
465
466 /* Generate in canonical form, as defined by DNSSEC
467 * RFC 4034, Section 6.2, i.e. all lower-case. */
468
b577e3d5
LP		 469 for (i = 0; i < l; i++)
470 w[i] = (uint8_t) ascii_tolower(d[i]);
a8812dd7
LP		 471 } else
472 /* Otherwise, just copy the string unaltered. This is
473 * essential for DNS-SD, where the casing of labels
474 * matters and needs to be retained. */
475 memcpy(w, d, l);
74b2466e
LP		 476
477 return 0;
478}
479
f6a5fec6
LP		 480int dns_packet_append_name(
481 DnsPacket *p,
482 const char *name,
483 bool allow_compression,
a3db237b 484 bool canonical_candidate,
f6a5fec6
LP		 485 size_t *start) {
486
74b2466e
LP		 487 size_t saved_size;
488 int r;
489
490 assert(p);
491 assert(name);
492
f6a5fec6
LP		 493 if (p->refuse_compression)
494 allow_compression = false;
495
74b2466e
LP		 496 saved_size = p->size;
497
e48b9a64 498 while (!dns_name_is_root(name)) {
08f904fd 499 const char *z = name;
74b2466e 500 char label[DNS_LABEL_MAX];
151226ab 501 size_t n = 0;
74b2466e 502
151226ab
ZJS		 503 if (allow_compression)
504 n = PTR_TO_SIZE(hashmap_get(p->names, name));
74b2466e
LP		 505 if (n > 0) {
506 assert(n < p->size);
507
508 if (n < 0x4000) {
509 r = dns_packet_append_uint16(p, 0xC000 | n, NULL);
510 if (r < 0)
511 goto fail;
512
513 goto done;
514 }
515 }
516
74b2466e
LP		 517 r = dns_label_unescape(&name, label, sizeof(label));
518 if (r < 0)
519 goto fail;
520
a3db237b 521 r = dns_packet_append_label(p, label, r, canonical_candidate, &n);
74b2466e
LP		 522 if (r < 0)
523 goto fail;
524
151226ab 525 if (allow_compression) {
08f904fd
LP		 526 _cleanup_free_ char *s = NULL;
527
528 s = strdup(z);
529 if (!s) {
530 r = -ENOMEM;
531 goto fail;
532 }
533
d5099efc 534 r = hashmap_ensure_allocated(&p->names, &dns_name_hash_ops);
151226ab
ZJS		 535 if (r < 0)
536 goto fail;
74b2466e 537
151226ab
ZJS		 538 r = hashmap_put(p->names, s, SIZE_TO_PTR(n));
539 if (r < 0)
540 goto fail;
74b2466e 541
151226ab
ZJS		 542 s = NULL;
543 }
74b2466e
LP		 544 }
545
546 r = dns_packet_append_uint8(p, 0, NULL);
547 if (r < 0)
548 return r;
549
550done:
551 if (start)
552 *start = saved_size;
553
554 return 0;
555
556fail:
557 dns_packet_truncate(p, saved_size);
558 return r;
559}
560
561int dns_packet_append_key(DnsPacket *p, const DnsResourceKey *k, size_t *start) {
562 size_t saved_size;
563 int r;
564
565 assert(p);
566 assert(k);
567
568 saved_size = p->size;
569
a3db237b 570 r = dns_packet_append_name(p, DNS_RESOURCE_KEY_NAME(k), true, true, NULL);
74b2466e
LP		 571 if (r < 0)
572 goto fail;
573
574 r = dns_packet_append_uint16(p, k->type, NULL);
575 if (r < 0)
576 goto fail;
577
578 r = dns_packet_append_uint16(p, k->class, NULL);
579 if (r < 0)
580 goto fail;
581
582 if (start)
583 *start = saved_size;
584
585 return 0;
586
587fail:
588 dns_packet_truncate(p, saved_size);
589 return r;
590}
591
e1a9f1a8 592static int dns_packet_append_type_window(DnsPacket *p, uint8_t window, uint8_t length, const uint8_t *types, size_t *start) {
50f1e641
TG		 593 size_t saved_size;
594 int r;
595
596 assert(p);
597 assert(types);
1792f223 598 assert(length > 0);
50f1e641 599
50f1e641
TG		 600 saved_size = p->size;
601
1792f223
TG		 602 r = dns_packet_append_uint8(p, window, NULL);
603 if (r < 0)
604 goto fail;
50f1e641 605
1792f223
TG		 606 r = dns_packet_append_uint8(p, length, NULL);
607 if (r < 0)
608 goto fail;
6fa91901 609
1792f223
TG		 610 r = dns_packet_append_blob(p, types, length, NULL);
611 if (r < 0)
612 goto fail;
50f1e641
TG		 613
614 if (start)
615 *start = saved_size;
616
617 return 0;
618fail:
619 dns_packet_truncate(p, saved_size);
620 return r;
621}
622
623static int dns_packet_append_types(DnsPacket *p, Bitmap *types, size_t *start) {
cb57dd41 624 Iterator i;
50f1e641 625 uint8_t window = 0;
1792f223 626 uint8_t entry = 0;
50f1e641
TG		 627 uint8_t bitmaps[32] = {};
628 unsigned n;
629 size_t saved_size;
630 int r;
631
632 assert(p);
50f1e641
TG		 633
634 saved_size = p->size;
635
cb57dd41 636 BITMAP_FOREACH(n, types, i) {
50f1e641
TG		 637 assert(n <= 0xffff);
638
1792f223
TG		 639 if ((n >> 8) != window && bitmaps[entry / 8] != 0) {
640 r = dns_packet_append_type_window(p, window, entry / 8 + 1, bitmaps, NULL);
50f1e641
TG		 641 if (r < 0)
642 goto fail;
643
1792f223 644 zero(bitmaps);
50f1e641
TG		 645 }
646
1792f223 647 window = n >> 8;
50f1e641
TG		 648 entry = n & 255;
649
650 bitmaps[entry / 8] |= 1 << (7 - (entry % 8));
651 }
652
d0ae14ff
LP		 653 if (bitmaps[entry / 8] != 0) {
654 r = dns_packet_append_type_window(p, window, entry / 8 + 1, bitmaps, NULL);
655 if (r < 0)
656 goto fail;
657 }
50f1e641
TG		 658
659 if (start)
660 *start = saved_size;
661
662 return 0;
663fail:
664 dns_packet_truncate(p, saved_size);
665 return r;
666}
667
dc913c9a 668/* Append the OPT pseudo-RR described in RFC6891 */
519ef046 669int dns_packet_append_opt(DnsPacket *p, uint16_t max_udp_size, bool edns0_do, size_t *start) {
dc913c9a
TG		 670 size_t saved_size;
671 int r;
672
673 assert(p);
674 /* we must never advertise supported packet size smaller than the legacy max */
675 assert(max_udp_size >= DNS_PACKET_UNICAST_SIZE_MAX);
676
519ef046
LP		 677 if (p->opt_start != (size_t) -1)
678 return -EBUSY;
679
680 assert(p->opt_size == (size_t) -1);
681
dc913c9a
TG		 682 saved_size = p->size;
683
684 /* empty name */
685 r = dns_packet_append_uint8(p, 0, NULL);
686 if (r < 0)
687 return r;
688
689 /* type */
690 r = dns_packet_append_uint16(p, DNS_TYPE_OPT, NULL);
691 if (r < 0)
692 goto fail;
693
694 /* maximum udp packet that can be received */
695 r = dns_packet_append_uint16(p, max_udp_size, NULL);
696 if (r < 0)
697 goto fail;
698
699 /* extended RCODE and VERSION */
700 r = dns_packet_append_uint16(p, 0, NULL);
701 if (r < 0)
702 goto fail;
703
7586f4d1
TG		 704 /* flags: DNSSEC OK (DO), see RFC3225 */
705 r = dns_packet_append_uint16(p, edns0_do ? EDNS0_OPT_DO : 0, NULL);
dc913c9a
TG		 706 if (r < 0)
707 goto fail;
708
709 /* RDLENGTH */
665408ac
LP		 710
711 if (edns0_do) {
712 /* If DO is on, also append RFC6975 Algorithm data */
713
714 static const uint8_t rfc6975[] = {
715
716 0, 5, /* OPTION_CODE: DAU */
717 0, 6, /* LIST_LENGTH */
718 DNSSEC_ALGORITHM_RSASHA1,
719 DNSSEC_ALGORITHM_RSASHA1_NSEC3_SHA1,
720 DNSSEC_ALGORITHM_RSASHA256,
721 DNSSEC_ALGORITHM_RSASHA512,
722 DNSSEC_ALGORITHM_ECDSAP256SHA256,
723 DNSSEC_ALGORITHM_ECDSAP384SHA384,
724
725 0, 6, /* OPTION_CODE: DHU */
726 0, 3, /* LIST_LENGTH */
727 DNSSEC_DIGEST_SHA1,
728 DNSSEC_DIGEST_SHA256,
729 DNSSEC_DIGEST_SHA384,
730
731 0, 7, /* OPTION_CODE: N3U */
732 0, 1, /* LIST_LENGTH */
733 NSEC3_ALGORITHM_SHA1,
734 };
735
736 r = dns_packet_append_uint16(p, sizeof(rfc6975), NULL);
737 if (r < 0)
738 goto fail;
739
740 r = dns_packet_append_blob(p, rfc6975, sizeof(rfc6975), NULL);
741 } else
742 r = dns_packet_append_uint16(p, 0, NULL);
743
dc913c9a
TG		 744 if (r < 0)
745 goto fail;
746
519ef046
LP		 747 DNS_PACKET_HEADER(p)->arcount = htobe16(DNS_PACKET_ARCOUNT(p) + 1);
748
749 p->opt_start = saved_size;
750 p->opt_size = p->size - saved_size;
751
dc913c9a
TG		 752 if (start)
753 *start = saved_size;
754
755 return 0;
756
757fail:
758 dns_packet_truncate(p, saved_size);
759 return r;
760}
761
519ef046
LP		 762int dns_packet_truncate_opt(DnsPacket *p) {
763 assert(p);
764
765 if (p->opt_start == (size_t) -1) {
766 assert(p->opt_size == (size_t) -1);
767 return 0;
768 }
769
770 assert(p->opt_size != (size_t) -1);
771 assert(DNS_PACKET_ARCOUNT(p) > 0);
772
773 if (p->opt_start + p->opt_size != p->size)
774 return -EBUSY;
775
776 dns_packet_truncate(p, p->opt_start);
777 DNS_PACKET_HEADER(p)->arcount = htobe16(DNS_PACKET_ARCOUNT(p) - 1);
778 p->opt_start = p->opt_size = (size_t) -1;
779
780 return 1;
781}
782
a8812dd7
LP		 783int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, size_t *start, size_t *rdata_start) {
784 size_t saved_size, rdlength_offset, end, rdlength, rds;
623a4c97
LP		 785 int r;
786
787 assert(p);
788 assert(rr);
789
790 saved_size = p->size;
791
792 r = dns_packet_append_key(p, rr->key, NULL);
793 if (r < 0)
794 goto fail;
795
796 r = dns_packet_append_uint32(p, rr->ttl, NULL);
797 if (r < 0)
798 goto fail;
799
800 /* Initially we write 0 here */
801 r = dns_packet_append_uint16(p, 0, &rdlength_offset);
802 if (r < 0)
803 goto fail;
804
a8812dd7
LP		 805 rds = p->size - saved_size;
806
0dae31d4 807 switch (rr->unparseable ? _DNS_TYPE_INVALID : rr->key->type) {
623a4c97 808
9c92ce6d
LP		 809 case DNS_TYPE_SRV:
810 r = dns_packet_append_uint16(p, rr->srv.priority, NULL);
811 if (r < 0)
812 goto fail;
813
814 r = dns_packet_append_uint16(p, rr->srv.weight, NULL);
815 if (r < 0)
816 goto fail;
817
818 r = dns_packet_append_uint16(p, rr->srv.port, NULL);
819 if (r < 0)
820 goto fail;
821
a3db237b 822 r = dns_packet_append_name(p, rr->srv.name, true, false, NULL);
9c92ce6d
LP		 823 break;
824
623a4c97
LP		 825 case DNS_TYPE_PTR:
826 case DNS_TYPE_NS:
827 case DNS_TYPE_CNAME:
8ac4e9e1 828 case DNS_TYPE_DNAME:
a3db237b 829 r = dns_packet_append_name(p, rr->ptr.name, true, false, NULL);
623a4c97
LP		 830 break;
831
832 case DNS_TYPE_HINFO:
833 r = dns_packet_append_string(p, rr->hinfo.cpu, NULL);
834 if (r < 0)
835 goto fail;
836
837 r = dns_packet_append_string(p, rr->hinfo.os, NULL);
838 break;
839
9de3e329 840 case DNS_TYPE_SPF: /* exactly the same as TXT */
2001c805 841 case DNS_TYPE_TXT:
2e276efc 842
2001c805 843 if (!rr->txt.items) {
1ccda9b7
LP		 844 /* RFC 6763, section 6.1 suggests to generate
845 * single empty string for an empty array. */
846
2001c805 847 r = dns_packet_append_raw_string(p, NULL, 0, NULL);
2e276efc
ZJS		 848 if (r < 0)
849 goto fail;
1ccda9b7 850 } else {
2001c805
LP		 851 DnsTxtItem *i;
852
853 LIST_FOREACH(items, i, rr->txt.items) {
854 r = dns_packet_append_raw_string(p, i->data, i->length, NULL);
1ccda9b7
LP		 855 if (r < 0)
856 goto fail;
857 }
2e276efc
ZJS		 858 }
859
6a6fc3df 860 r = 0;
2e276efc 861 break;
2e276efc 862
623a4c97
LP		 863 case DNS_TYPE_A:
864 r = dns_packet_append_blob(p, &rr->a.in_addr, sizeof(struct in_addr), NULL);
865 break;
866
867 case DNS_TYPE_AAAA:
868 r = dns_packet_append_blob(p, &rr->aaaa.in6_addr, sizeof(struct in6_addr), NULL);
869 break;
870
871 case DNS_TYPE_SOA:
a3db237b 872 r = dns_packet_append_name(p, rr->soa.mname, true, false, NULL);
623a4c97
LP		 873 if (r < 0)
874 goto fail;
875
a3db237b 876 r = dns_packet_append_name(p, rr->soa.rname, true, false, NULL);
623a4c97
LP		 877 if (r < 0)
878 goto fail;
879
880 r = dns_packet_append_uint32(p, rr->soa.serial, NULL);
881 if (r < 0)
882 goto fail;
883
884 r = dns_packet_append_uint32(p, rr->soa.refresh, NULL);
885 if (r < 0)
886 goto fail;
887
888 r = dns_packet_append_uint32(p, rr->soa.retry, NULL);
889 if (r < 0)
890 goto fail;
891
892 r = dns_packet_append_uint32(p, rr->soa.expire, NULL);
893 if (r < 0)
894 goto fail;
895
896 r = dns_packet_append_uint32(p, rr->soa.minimum, NULL);
897 break;
898
899 case DNS_TYPE_MX:
946c7094
ZJS		 900 r = dns_packet_append_uint16(p, rr->mx.priority, NULL);
901 if (r < 0)
902 goto fail;
903
a3db237b 904 r = dns_packet_append_name(p, rr->mx.exchange, true, false, NULL);
946c7094
ZJS		 905 break;
906
0dae31d4
ZJS		 907 case DNS_TYPE_LOC:
908 r = dns_packet_append_uint8(p, rr->loc.version, NULL);
909 if (r < 0)
910 goto fail;
911
912 r = dns_packet_append_uint8(p, rr->loc.size, NULL);
913 if (r < 0)
914 goto fail;
915
916 r = dns_packet_append_uint8(p, rr->loc.horiz_pre, NULL);
917 if (r < 0)
918 goto fail;
919
920 r = dns_packet_append_uint8(p, rr->loc.vert_pre, NULL);
921 if (r < 0)
922 goto fail;
923
afbc4f26 924 r = dns_packet_append_uint32(p, rr->loc.latitude, NULL);
0dae31d4
ZJS		 925 if (r < 0)
926 goto fail;
927
afbc4f26 928 r = dns_packet_append_uint32(p, rr->loc.longitude, NULL);
0dae31d4
ZJS		 929 if (r < 0)
930 goto fail;
931
afbc4f26 932 r = dns_packet_append_uint32(p, rr->loc.altitude, NULL);
0dae31d4
ZJS		 933 break;
934
abf126a3
TG		 935 case DNS_TYPE_DS:
936 r = dns_packet_append_uint16(p, rr->ds.key_tag, NULL);
937 if (r < 0)
938 goto fail;
939
940 r = dns_packet_append_uint8(p, rr->ds.algorithm, NULL);
941 if (r < 0)
942 goto fail;
943
944 r = dns_packet_append_uint8(p, rr->ds.digest_type, NULL);
945 if (r < 0)
946 goto fail;
947
948 r = dns_packet_append_blob(p, rr->ds.digest, rr->ds.digest_size, NULL);
949 break;
950
623a4c97 951 case DNS_TYPE_SSHFP:
42cc2eeb
LP		 952 r = dns_packet_append_uint8(p, rr->sshfp.algorithm, NULL);
953 if (r < 0)
954 goto fail;
8db0d2f5 955
42cc2eeb
LP		 956 r = dns_packet_append_uint8(p, rr->sshfp.fptype, NULL);
957 if (r < 0)
958 goto fail;
959
549c1a25 960 r = dns_packet_append_blob(p, rr->sshfp.fingerprint, rr->sshfp.fingerprint_size, NULL);
42cc2eeb
LP		 961 break;
962
8db0d2f5 963 case DNS_TYPE_DNSKEY:
f91dc240 964 r = dns_packet_append_uint16(p, rr->dnskey.flags, NULL);
8db0d2f5
ZJS		 965 if (r < 0)
966 goto fail;
967
f91dc240 968 r = dns_packet_append_uint8(p, rr->dnskey.protocol, NULL);
8db0d2f5
ZJS		 969 if (r < 0)
970 goto fail;
971
972 r = dns_packet_append_uint8(p, rr->dnskey.algorithm, NULL);
973 if (r < 0)
974 goto fail;
975
976 r = dns_packet_append_blob(p, rr->dnskey.key, rr->dnskey.key_size, NULL);
977 break;
978
151226ab
ZJS		 979 case DNS_TYPE_RRSIG:
980 r = dns_packet_append_uint16(p, rr->rrsig.type_covered, NULL);
981 if (r < 0)
982 goto fail;
983
984 r = dns_packet_append_uint8(p, rr->rrsig.algorithm, NULL);
985 if (r < 0)
986 goto fail;
987
988 r = dns_packet_append_uint8(p, rr->rrsig.labels, NULL);
989 if (r < 0)
990 goto fail;
991
992 r = dns_packet_append_uint32(p, rr->rrsig.original_ttl, NULL);
993 if (r < 0)
994 goto fail;
995
996 r = dns_packet_append_uint32(p, rr->rrsig.expiration, NULL);
997 if (r < 0)
998 goto fail;
999
1000 r = dns_packet_append_uint32(p, rr->rrsig.inception, NULL);
1001 if (r < 0)
1002 goto fail;
1003
0b1b17d3 1004 r = dns_packet_append_uint16(p, rr->rrsig.key_tag, NULL);
151226ab
ZJS		 1005 if (r < 0)
1006 goto fail;
1007
a3db237b 1008 r = dns_packet_append_name(p, rr->rrsig.signer, false, true, NULL);
151226ab
ZJS		 1009 if (r < 0)
1010 goto fail;
1011
1012 r = dns_packet_append_blob(p, rr->rrsig.signature, rr->rrsig.signature_size, NULL);
1013 break;
1014
50f1e641 1015 case DNS_TYPE_NSEC:
a3db237b 1016 r = dns_packet_append_name(p, rr->nsec.next_domain_name, false, false, NULL);
50f1e641
TG		 1017 if (r < 0)
1018 goto fail;
1019
1020 r = dns_packet_append_types(p, rr->nsec.types, NULL);
1021 if (r < 0)
1022 goto fail;
1023
5d45a880 1024 break;
d75acfb0 1025
5d45a880
TG		 1026 case DNS_TYPE_NSEC3:
1027 r = dns_packet_append_uint8(p, rr->nsec3.algorithm, NULL);
1028 if (r < 0)
1029 goto fail;
1030
1031 r = dns_packet_append_uint8(p, rr->nsec3.flags, NULL);
1032 if (r < 0)
1033 goto fail;
1034
1035 r = dns_packet_append_uint16(p, rr->nsec3.iterations, NULL);
1036 if (r < 0)
1037 goto fail;
1038
1039 r = dns_packet_append_uint8(p, rr->nsec3.salt_size, NULL);
1040 if (r < 0)
1041 goto fail;
1042
1043 r = dns_packet_append_blob(p, rr->nsec3.salt, rr->nsec3.salt_size, NULL);
1044 if (r < 0)
1045 goto fail;
1046
1047 r = dns_packet_append_uint8(p, rr->nsec3.next_hashed_name_size, NULL);
1048 if (r < 0)
1049 goto fail;
1050
1051 r = dns_packet_append_blob(p, rr->nsec3.next_hashed_name, rr->nsec3.next_hashed_name_size, NULL);
1052 if (r < 0)
1053 goto fail;
1054
1055 r = dns_packet_append_types(p, rr->nsec3.types, NULL);
1056 if (r < 0)
1057 goto fail;
1058
50f1e641 1059 break;
d75acfb0
LP		 1060
1061 case DNS_TYPE_OPT:
0dae31d4 1062 case _DNS_TYPE_INVALID: /* unparseable */
623a4c97 1063 default:
0dae31d4 1064
623a4c97
LP		 1065 r = dns_packet_append_blob(p, rr->generic.data, rr->generic.size, NULL);
1066 break;
1067 }
1068 if (r < 0)
1069 goto fail;
1070
1071 /* Let's calculate the actual data size and update the field */
1072 rdlength = p->size - rdlength_offset - sizeof(uint16_t);
1073 if (rdlength > 0xFFFF) {
555f5cdc 1074 r = -ENOSPC;
623a4c97
LP		 1075 goto fail;
1076 }
1077
1078 end = p->size;
1079 p->size = rdlength_offset;
1080 r = dns_packet_append_uint16(p, rdlength, NULL);
1081 if (r < 0)
1082 goto fail;
1083 p->size = end;
1084
351e6342
LP		 1085 if (start)
1086 *start = saved_size;
1087
a8812dd7
LP		 1088 if (rdata_start)
1089 *rdata_start = rds;
1090
623a4c97
LP		 1091 return 0;
1092
1093fail:
1094 dns_packet_truncate(p, saved_size);
1095 return r;
1096}
1097
74b2466e
LP		 1098int dns_packet_read(DnsPacket *p, size_t sz, const void **ret, size_t *start) {
1099 assert(p);
1100
1101 if (p->rindex + sz > p->size)
1102 return -EMSGSIZE;
1103
1104 if (ret)
1105 *ret = (uint8_t*) DNS_PACKET_DATA(p) + p->rindex;
1106
1107 if (start)
1108 *start = p->rindex;
1109
1110 p->rindex += sz;
1111 return 0;
1112}
1113
8ba9fd9c 1114void dns_packet_rewind(DnsPacket *p, size_t idx) {
74b2466e
LP		 1115 assert(p);
1116 assert(idx <= p->size);
1117 assert(idx >= DNS_PACKET_HEADER_SIZE);
1118
1119 p->rindex = idx;
1120}
1121
623a4c97
LP		 1122int dns_packet_read_blob(DnsPacket *p, void *d, size_t sz, size_t *start) {
1123 const void *q;
1124 int r;
1125
1126 assert(p);
1127 assert(d);
1128
1129 r = dns_packet_read(p, sz, &q, start);
1130 if (r < 0)
1131 return r;
1132
1133 memcpy(d, q, sz);
1134 return 0;
1135}
1136
f5430a3e
LP		 1137static int dns_packet_read_memdup(
1138 DnsPacket *p, size_t size,
1139 void **ret, size_t *ret_size,
1140 size_t *ret_start) {
1141
1142 const void *src;
1143 size_t start;
1144 int r;
1145
1146 assert(p);
1147 assert(ret);
1148
1149 r = dns_packet_read(p, size, &src, &start);
1150 if (r < 0)
1151 return r;
1152
1153 if (size <= 0)
1154 *ret = NULL;
1155 else {
1156 void *copy;
1157
1158 copy = memdup(src, size);
1159 if (!copy)
1160 return -ENOMEM;
1161
1162 *ret = copy;
1163 }
1164
1165 if (ret_size)
1166 *ret_size = size;
1167 if (ret_start)
1168 *ret_start = start;
1169
1170 return 0;
1171}
1172
74b2466e
LP		 1173int dns_packet_read_uint8(DnsPacket *p, uint8_t *ret, size_t *start) {
1174 const void *d;
1175 int r;
1176
1177 assert(p);
1178
1179 r = dns_packet_read(p, sizeof(uint8_t), &d, start);
1180 if (r < 0)
1181 return r;
1182
1183 *ret = ((uint8_t*) d)[0];
1184 return 0;
1185}
1186
1187int dns_packet_read_uint16(DnsPacket *p, uint16_t *ret, size_t *start) {
1188 const void *d;
1189 int r;
1190
1191 assert(p);
1192
1193 r = dns_packet_read(p, sizeof(uint16_t), &d, start);
1194 if (r < 0)
1195 return r;
1196
725ca0e5
TG		 1197 *ret = unaligned_read_be16(d);
1198
74b2466e
LP		 1199 return 0;
1200}
1201
1202int dns_packet_read_uint32(DnsPacket *p, uint32_t *ret, size_t *start) {
1203 const void *d;
1204 int r;
1205
1206 assert(p);
1207
1208 r = dns_packet_read(p, sizeof(uint32_t), &d, start);
1209 if (r < 0)
1210 return r;
1211
725ca0e5 1212 *ret = unaligned_read_be32(d);
74b2466e
LP		 1213
1214 return 0;
1215}
1216
1217int dns_packet_read_string(DnsPacket *p, char **ret, size_t *start) {
1218 size_t saved_rindex;
1219 const void *d;
1220 char *t;
1221 uint8_t c;
1222 int r;
1223
1224 assert(p);
1225
1226 saved_rindex = p->rindex;
1227
1228 r = dns_packet_read_uint8(p, &c, NULL);
1229 if (r < 0)
1230 goto fail;
1231
1232 r = dns_packet_read(p, c, &d, NULL);
1233 if (r < 0)
1234 goto fail;
1235
1236 if (memchr(d, 0, c)) {
1237 r = -EBADMSG;
1238 goto fail;
1239 }
1240
1241 t = strndup(d, c);
1242 if (!t) {
1243 r = -ENOMEM;
1244 goto fail;
1245 }
1246
1247 if (!utf8_is_valid(t)) {
1248 free(t);
1249 r = -EBADMSG;
1250 goto fail;
1251 }
1252
1253 *ret = t;
1254
1255 if (start)
1256 *start = saved_rindex;
1257
1258 return 0;
1259
1260fail:
1261 dns_packet_rewind(p, saved_rindex);
1262 return r;
1263}
1264
2001c805
LP		 1265int dns_packet_read_raw_string(DnsPacket *p, const void **ret, size_t *size, size_t *start) {
1266 size_t saved_rindex;
1267 uint8_t c;
1268 int r;
1269
1270 assert(p);
1271
1272 saved_rindex = p->rindex;
1273
1274 r = dns_packet_read_uint8(p, &c, NULL);
1275 if (r < 0)
1276 goto fail;
1277
1278 r = dns_packet_read(p, c, ret, NULL);
1279 if (r < 0)
1280 goto fail;
1281
1282 if (size)
1283 *size = c;
1284 if (start)
1285 *start = saved_rindex;
1286
1287 return 0;
1288
1289fail:
1290 dns_packet_rewind(p, saved_rindex);
1291 return r;
1292}
1293
f6a5fec6
LP		 1294int dns_packet_read_name(
1295 DnsPacket *p,
1296 char **_ret,
1297 bool allow_compression,
1298 size_t *start) {
1299
c75dbf9b 1300 size_t saved_rindex, after_rindex = 0, jump_barrier;
74b2466e
LP		 1301 _cleanup_free_ char *ret = NULL;
1302 size_t n = 0, allocated = 0;
1303 bool first = true;
1304 int r;
1305
1306 assert(p);
1307 assert(_ret);
1308
f6a5fec6
LP		 1309 if (p->refuse_compression)
1310 allow_compression = false;
1311
74b2466e 1312 saved_rindex = p->rindex;
c75dbf9b 1313 jump_barrier = p->rindex;
74b2466e
LP		 1314
1315 for (;;) {
1316 uint8_t c, d;
1317
1318 r = dns_packet_read_uint8(p, &c, NULL);
1319 if (r < 0)
1320 goto fail;
1321
1322 if (c == 0)
1323 /* End of name */
1324 break;
1325 else if (c <= 63) {
74b2466e
LP		 1326 const char *label;
1327
1328 /* Literal label */
1329 r = dns_packet_read(p, c, (const void**) &label, NULL);
1330 if (r < 0)
1331 goto fail;
1332
422baca0 1333 if (!GREEDY_REALLOC(ret, allocated, n + !first + DNS_LABEL_ESCAPED_MAX)) {
74b2466e
LP		 1334 r = -ENOMEM;
1335 goto fail;
1336 }
1337
422baca0 1338 if (first)
74b2466e 1339 first = false;
422baca0
LP		 1340 else
1341 ret[n++] = '.';
1342
1343 r = dns_label_escape(label, c, ret + n, DNS_LABEL_ESCAPED_MAX);
1344 if (r < 0)
1345 goto fail;
74b2466e 1346
74b2466e
LP		 1347 n += r;
1348 continue;
151226ab 1349 } else if (allow_compression && (c & 0xc0) == 0xc0) {
74b2466e
LP		 1350 uint16_t ptr;
1351
1352 /* Pointer */
1353 r = dns_packet_read_uint8(p, &d, NULL);
1354 if (r < 0)
1355 goto fail;
1356
1357 ptr = (uint16_t) (c & ~0xc0) << 8 | (uint16_t) d;
c75dbf9b 1358 if (ptr < DNS_PACKET_HEADER_SIZE || ptr >= jump_barrier) {
74b2466e
LP		 1359 r = -EBADMSG;
1360 goto fail;
1361 }
1362
1363 if (after_rindex == 0)
1364 after_rindex = p->rindex;
1365
f131770b 1366 /* Jumps are limited to a "prior occurrence" (RFC-1035 4.1.4) */
c75dbf9b 1367 jump_barrier = ptr;
74b2466e 1368 p->rindex = ptr;
59aa5821
SP		 1369 } else {
1370 r = -EBADMSG;
74b2466e 1371 goto fail;
59aa5821 1372 }
74b2466e
LP		 1373 }
1374
1375 if (!GREEDY_REALLOC(ret, allocated, n + 1)) {
1376 r = -ENOMEM;
1377 goto fail;
1378 }
1379
1380 ret[n] = 0;
1381
1382 if (after_rindex != 0)
1383 p->rindex= after_rindex;
1384
1385 *_ret = ret;
1386 ret = NULL;
1387
1388 if (start)
1389 *start = saved_rindex;
1390
1391 return 0;
1392
1393fail:
1394 dns_packet_rewind(p, saved_rindex);
1395 return r;
1396}
1397
50f1e641
TG		 1398static int dns_packet_read_type_window(DnsPacket *p, Bitmap **types, size_t *start) {
1399 uint8_t window;
1400 uint8_t length;
1401 const uint8_t *bitmap;
2ad613ad 1402 uint8_t bit = 0;
50f1e641
TG		 1403 unsigned i;
1404 bool found = false;
1405 size_t saved_rindex;
1406 int r;
1407
1408 assert(p);
1409 assert(types);
1410
1411 saved_rindex = p->rindex;
1412
1413 r = bitmap_ensure_allocated(types);
1414 if (r < 0)
1415 goto fail;
1416
1417 r = dns_packet_read_uint8(p, &window, NULL);
1418 if (r < 0)
1419 goto fail;
1420
1421 r = dns_packet_read_uint8(p, &length, NULL);
1422 if (r < 0)
1423 goto fail;
1424
1425 if (length == 0 || length > 32)
1426 return -EBADMSG;
1427
1428 r = dns_packet_read(p, length, (const void **)&bitmap, NULL);
1429 if (r < 0)
1430 goto fail;
1431
1432 for (i = 0; i < length; i++) {
1433 uint8_t bitmask = 1 << 7;
50f1e641
TG		 1434
1435 if (!bitmap[i]) {
1436 found = false;
2ad613ad 1437 bit += 8;
50f1e641
TG		 1438 continue;
1439 }
1440
1441 found = true;
1442
1443 while (bitmask) {
1444 if (bitmap[i] & bitmask) {
1445 uint16_t n;
1446
50f1e641
TG		 1447 n = (uint16_t) window << 8 | (uint16_t) bit;
1448
8e6edc49
TG		 1449 /* Ignore pseudo-types. see RFC4034 section 4.1.2 */
1450 if (dns_type_is_pseudo(n))
1451 continue;
1452
50f1e641
TG		 1453 r = bitmap_set(*types, n);
1454 if (r < 0)
1455 goto fail;
1456 }
1457
1458 bit ++;
1459 bitmask >>= 1;
1460 }
1461 }
1462
1463 if (!found)
1464 return -EBADMSG;
1465
1466 if (start)
1467 *start = saved_rindex;
1468
1469 return 0;
1470fail:
1471 dns_packet_rewind(p, saved_rindex);
1472 return r;
1473}
1474
89492aaf
TG		 1475static int dns_packet_read_type_windows(DnsPacket *p, Bitmap **types, size_t size, size_t *start) {
1476 size_t saved_rindex;
1477 int r;
1478
1479 saved_rindex = p->rindex;
1480
1481 while (p->rindex < saved_rindex + size) {
1482 r = dns_packet_read_type_window(p, types, NULL);
1483 if (r < 0)
1484 goto fail;
1485
1486 /* don't read past end of current RR */
1487 if (p->rindex > saved_rindex + size) {
1488 r = -EBADMSG;
1489 goto fail;
1490 }
1491 }
1492
1493 if (p->rindex != saved_rindex + size) {
1494 r = -EBADMSG;
1495 goto fail;
1496 }
1497
1498 if (start)
1499 *start = saved_rindex;
1500
1501 return 0;
1502fail:
1503 dns_packet_rewind(p, saved_rindex);
1504 return r;
1505}
1506
d2579eec 1507int dns_packet_read_key(DnsPacket *p, DnsResourceKey **ret, bool *ret_cache_flush, size_t *start) {
faa133f3 1508 _cleanup_free_ char *name = NULL;
d2579eec 1509 bool cache_flush = false;
faa133f3
LP		 1510 uint16_t class, type;
1511 DnsResourceKey *key;
74b2466e
LP		 1512 size_t saved_rindex;
1513 int r;
1514
1515 assert(p);
1516 assert(ret);
1517
1518 saved_rindex = p->rindex;
1519
151226ab 1520 r = dns_packet_read_name(p, &name, true, NULL);
74b2466e
LP		 1521 if (r < 0)
1522 goto fail;
1523
faa133f3 1524 r = dns_packet_read_uint16(p, &type, NULL);
74b2466e
LP		 1525 if (r < 0)
1526 goto fail;
1527
faa133f3 1528 r = dns_packet_read_uint16(p, &class, NULL);
74b2466e
LP		 1529 if (r < 0)
1530 goto fail;
1531
23502de3
DM		 1532 if (p->protocol == DNS_PROTOCOL_MDNS) {
1533 /* See RFC6762, Section 10.2 */
1534
d2579eec 1535 if (type != DNS_TYPE_OPT && (class & MDNS_RR_CACHE_FLUSH)) {
23502de3 1536 class &= ~MDNS_RR_CACHE_FLUSH;
d2579eec
LP		 1537 cache_flush = true;
1538 }
23502de3
DM		 1539 }
1540
faa133f3
LP		 1541 key = dns_resource_key_new_consume(class, type, name);
1542 if (!key) {
1543 r = -ENOMEM;
1544 goto fail;
1545 }
1546
1547 name = NULL;
1548 *ret = key;
74b2466e 1549
d2579eec
LP		 1550 if (ret_cache_flush)
1551 *ret_cache_flush = cache_flush;
74b2466e
LP		 1552 if (start)
1553 *start = saved_rindex;
1554
1555 return 0;
1556fail:
1557 dns_packet_rewind(p, saved_rindex);
1558 return r;
1559}
1560
afbc4f26
ZJS		 1561static bool loc_size_ok(uint8_t size) {
1562 uint8_t m = size >> 4, e = size & 0xF;
1563
1564 return m <= 9 && e <= 9 && (m > 0 || e == 0);
1565}
1566
d2579eec 1567int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, bool *ret_cache_flush, size_t *start) {
faa133f3
LP		 1568 _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
1569 _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
74b2466e
LP		 1570 size_t saved_rindex, offset;
1571 uint16_t rdlength;
d2579eec 1572 bool cache_flush;
74b2466e
LP		 1573 int r;
1574
1575 assert(p);
1576 assert(ret);
1577
4e0296a9 1578 saved_rindex = p->rindex;
74b2466e 1579
d2579eec 1580 r = dns_packet_read_key(p, &key, &cache_flush, NULL);
74b2466e
LP		 1581 if (r < 0)
1582 goto fail;
1583
222148b6 1584 if (!dns_class_is_valid_rr(key->class)||
c463eb78 1585 !dns_type_is_valid_rr(key->type)) {
0e2bcd6a
LP		 1586 r = -EBADMSG;
1587 goto fail;
1588 }
1589
faa133f3
LP		 1590 rr = dns_resource_record_new(key);
1591 if (!rr) {
1592 r = -ENOMEM;
1593 goto fail;
1594 }
1595
74b2466e
LP		 1596 r = dns_packet_read_uint32(p, &rr->ttl, NULL);
1597 if (r < 0)
1598 goto fail;
1599
0d0b52d7
LP		 1600 /* RFC 2181, Section 8, suggests to
1601 * treat a TTL with the MSB set as a zero TTL. */
1602 if (rr->ttl & UINT32_C(0x80000000))
1603 rr->ttl = 0;
1604
74b2466e
LP		 1605 r = dns_packet_read_uint16(p, &rdlength, NULL);
1606 if (r < 0)
1607 goto fail;
1608
1609 if (p->rindex + rdlength > p->size) {
1610 r = -EBADMSG;
1611 goto fail;
1612 }
1613
1614 offset = p->rindex;
1615
faa133f3 1616 switch (rr->key->type) {
74b2466e 1617
9c92ce6d
LP		 1618 case DNS_TYPE_SRV:
1619 r = dns_packet_read_uint16(p, &rr->srv.priority, NULL);
1620 if (r < 0)
1621 goto fail;
1622 r = dns_packet_read_uint16(p, &rr->srv.weight, NULL);
1623 if (r < 0)
1624 goto fail;
1625 r = dns_packet_read_uint16(p, &rr->srv.port, NULL);
1626 if (r < 0)
1627 goto fail;
151226ab 1628 r = dns_packet_read_name(p, &rr->srv.name, true, NULL);
9c92ce6d
LP		 1629 break;
1630
74b2466e
LP		 1631 case DNS_TYPE_PTR:
1632 case DNS_TYPE_NS:
1633 case DNS_TYPE_CNAME:
8ac4e9e1 1634 case DNS_TYPE_DNAME:
151226ab 1635 r = dns_packet_read_name(p, &rr->ptr.name, true, NULL);
74b2466e
LP		 1636 break;
1637
1638 case DNS_TYPE_HINFO:
1639 r = dns_packet_read_string(p, &rr->hinfo.cpu, NULL);
1640 if (r < 0)
1641 goto fail;
1642
1643 r = dns_packet_read_string(p, &rr->hinfo.os, NULL);
1644 break;
1645
9de3e329 1646 case DNS_TYPE_SPF: /* exactly the same as TXT */
1ccda9b7
LP		 1647 case DNS_TYPE_TXT:
1648 if (rdlength <= 0) {
2001c805 1649 DnsTxtItem *i;
1ccda9b7
LP		 1650 /* RFC 6763, section 6.1 suggests to treat
1651 * empty TXT RRs as equivalent to a TXT record
1652 * with a single empty string. */
0e3434ae 1653
2001c805
LP		 1654 i = malloc0(offsetof(DnsTxtItem, data) + 1); /* for safety reasons we add an extra NUL byte */
1655 if (!i)
1656 return -ENOMEM;
1657
1658 rr->txt.items = i;
1ccda9b7 1659 } else {
2001c805
LP		 1660 DnsTxtItem *last = NULL;
1661
1ccda9b7 1662 while (p->rindex < offset + rdlength) {
2001c805
LP		 1663 DnsTxtItem *i;
1664 const void *data;
1665 size_t sz;
2e276efc 1666
2001c805 1667 r = dns_packet_read_raw_string(p, &data, &sz, NULL);
1ccda9b7 1668 if (r < 0)
2001c805 1669 return r;
1ccda9b7 1670
2001c805
LP		 1671 i = malloc0(offsetof(DnsTxtItem, data) + sz + 1); /* extra NUL byte at the end */
1672 if (!i)
1673 return -ENOMEM;
1674
1675 memcpy(i->data, data, sz);
1676 i->length = sz;
1677
1678 LIST_INSERT_AFTER(items, rr->txt.items, last, i);
1679 last = i;
1ccda9b7 1680 }
6a6fc3df
LP		 1681 }
1682
1683 r = 0;
2e276efc 1684 break;
2e276efc 1685
74b2466e 1686 case DNS_TYPE_A:
623a4c97 1687 r = dns_packet_read_blob(p, &rr->a.in_addr, sizeof(struct in_addr), NULL);
74b2466e
LP		 1688 break;
1689
1690 case DNS_TYPE_AAAA:
623a4c97 1691 r = dns_packet_read_blob(p, &rr->aaaa.in6_addr, sizeof(struct in6_addr), NULL);
74b2466e
LP		 1692 break;
1693
7e8e0422 1694 case DNS_TYPE_SOA:
151226ab 1695 r = dns_packet_read_name(p, &rr->soa.mname, true, NULL);
7e8e0422
LP		 1696 if (r < 0)
1697 goto fail;
1698
151226ab 1699 r = dns_packet_read_name(p, &rr->soa.rname, true, NULL);
7e8e0422
LP		 1700 if (r < 0)
1701 goto fail;
1702
1703 r = dns_packet_read_uint32(p, &rr->soa.serial, NULL);
1704 if (r < 0)
1705 goto fail;
1706
1707 r = dns_packet_read_uint32(p, &rr->soa.refresh, NULL);
1708 if (r < 0)
1709 goto fail;
1710
1711 r = dns_packet_read_uint32(p, &rr->soa.retry, NULL);
1712 if (r < 0)
1713 goto fail;
1714
1715 r = dns_packet_read_uint32(p, &rr->soa.expire, NULL);
1716 if (r < 0)
1717 goto fail;
1718
1719 r = dns_packet_read_uint32(p, &rr->soa.minimum, NULL);
1720 break;
1721
623a4c97 1722 case DNS_TYPE_MX:
946c7094
ZJS		 1723 r = dns_packet_read_uint16(p, &rr->mx.priority, NULL);
1724 if (r < 0)
1725 goto fail;
1726
151226ab 1727 r = dns_packet_read_name(p, &rr->mx.exchange, true, NULL);
946c7094
ZJS		 1728 break;
1729
0dae31d4
ZJS		 1730 case DNS_TYPE_LOC: {
1731 uint8_t t;
1732 size_t pos;
1733
1734 r = dns_packet_read_uint8(p, &t, &pos);
1735 if (r < 0)
1736 goto fail;
1737
1738 if (t == 0) {
1739 rr->loc.version = t;
1740
1741 r = dns_packet_read_uint8(p, &rr->loc.size, NULL);
1742 if (r < 0)
1743 goto fail;
1744
afbc4f26
ZJS		 1745 if (!loc_size_ok(rr->loc.size)) {
1746 r = -EBADMSG;
1747 goto fail;
1748 }
1749
0dae31d4
ZJS		 1750 r = dns_packet_read_uint8(p, &rr->loc.horiz_pre, NULL);
1751 if (r < 0)
1752 goto fail;
1753
afbc4f26
ZJS		 1754 if (!loc_size_ok(rr->loc.horiz_pre)) {
1755 r = -EBADMSG;
1756 goto fail;
1757 }
1758
0dae31d4
ZJS		 1759 r = dns_packet_read_uint8(p, &rr->loc.vert_pre, NULL);
1760 if (r < 0)
1761 goto fail;
1762
afbc4f26
ZJS		 1763 if (!loc_size_ok(rr->loc.vert_pre)) {
1764 r = -EBADMSG;
1765 goto fail;
1766 }
1767
0dae31d4
ZJS		 1768 r = dns_packet_read_uint32(p, &rr->loc.latitude, NULL);
1769 if (r < 0)
1770 goto fail;
1771
1772 r = dns_packet_read_uint32(p, &rr->loc.longitude, NULL);
1773 if (r < 0)
1774 goto fail;
1775
1776 r = dns_packet_read_uint32(p, &rr->loc.altitude, NULL);
1777 if (r < 0)
1778 goto fail;
1779
1780 break;
1781 } else {
1782 dns_packet_rewind(p, pos);
1783 rr->unparseable = true;
afbc4f26 1784 goto unparseable;
0dae31d4
ZJS		 1785 }
1786 }
1787
abf126a3
TG		 1788 case DNS_TYPE_DS:
1789 r = dns_packet_read_uint16(p, &rr->ds.key_tag, NULL);
1790 if (r < 0)
1791 goto fail;
1792
1793 r = dns_packet_read_uint8(p, &rr->ds.algorithm, NULL);
1794 if (r < 0)
1795 goto fail;
1796
1797 r = dns_packet_read_uint8(p, &rr->ds.digest_type, NULL);
1798 if (r < 0)
1799 goto fail;
1800
f5430a3e
LP		 1801 r = dns_packet_read_memdup(p, rdlength - 4,
1802 &rr->ds.digest, &rr->ds.digest_size,
1803 NULL);
abf126a3
TG		 1804 if (r < 0)
1805 goto fail;
1806
f1d178cc
TG		 1807 if (rr->ds.digest_size <= 0) {
1808 /* the accepted size depends on the algorithm, but for now
1809 just ensure that the value is greater than zero */
1810 r = -EBADMSG;
1811 goto fail;
1812 }
1813
abf126a3 1814 break;
d75acfb0 1815
623a4c97 1816 case DNS_TYPE_SSHFP:
42cc2eeb
LP		 1817 r = dns_packet_read_uint8(p, &rr->sshfp.algorithm, NULL);
1818 if (r < 0)
1819 goto fail;
1820
1821 r = dns_packet_read_uint8(p, &rr->sshfp.fptype, NULL);
1822 if (r < 0)
1823 goto fail;
1824
f5430a3e 1825 r = dns_packet_read_memdup(p, rdlength - 2,
549c1a25 1826 &rr->sshfp.fingerprint, &rr->sshfp.fingerprint_size,
f5430a3e 1827 NULL);
f1d178cc 1828
549c1a25 1829 if (rr->sshfp.fingerprint_size <= 0) {
f1d178cc
TG		 1830 /* the accepted size depends on the algorithm, but for now
1831 just ensure that the value is greater than zero */
1832 r = -EBADMSG;
1833 goto fail;
1834 }
1835
8db0d2f5
ZJS		 1836 break;
1837
f91dc240
LP		 1838 case DNS_TYPE_DNSKEY:
1839 r = dns_packet_read_uint16(p, &rr->dnskey.flags, NULL);
8db0d2f5
ZJS		 1840 if (r < 0)
1841 goto fail;
1842
f91dc240 1843 r = dns_packet_read_uint8(p, &rr->dnskey.protocol, NULL);
8db0d2f5
ZJS		 1844 if (r < 0)
1845 goto fail;
1846
8db0d2f5
ZJS		 1847 r = dns_packet_read_uint8(p, &rr->dnskey.algorithm, NULL);
1848 if (r < 0)
1849 goto fail;
1850
f5430a3e
LP		 1851 r = dns_packet_read_memdup(p, rdlength - 4,
1852 &rr->dnskey.key, &rr->dnskey.key_size,
1853 NULL);
f1d178cc
TG		 1854
1855 if (rr->dnskey.key_size <= 0) {
1856 /* the accepted size depends on the algorithm, but for now
1857 just ensure that the value is greater than zero */
1858 r = -EBADMSG;
1859 goto fail;
1860 }
1861
42cc2eeb
LP		 1862 break;
1863
151226ab
ZJS		 1864 case DNS_TYPE_RRSIG:
1865 r = dns_packet_read_uint16(p, &rr->rrsig.type_covered, NULL);
1866 if (r < 0)
1867 goto fail;
1868
1869 r = dns_packet_read_uint8(p, &rr->rrsig.algorithm, NULL);
1870 if (r < 0)
1871 goto fail;
1872
1873 r = dns_packet_read_uint8(p, &rr->rrsig.labels, NULL);
1874 if (r < 0)
1875 goto fail;
1876
1877 r = dns_packet_read_uint32(p, &rr->rrsig.original_ttl, NULL);
1878 if (r < 0)
1879 goto fail;
1880
1881 r = dns_packet_read_uint32(p, &rr->rrsig.expiration, NULL);
1882 if (r < 0)
1883 goto fail;
1884
1885 r = dns_packet_read_uint32(p, &rr->rrsig.inception, NULL);
1886 if (r < 0)
1887 goto fail;
1888
1889 r = dns_packet_read_uint16(p, &rr->rrsig.key_tag, NULL);
1890 if (r < 0)
1891 goto fail;
1892
1893 r = dns_packet_read_name(p, &rr->rrsig.signer, false, NULL);
1894 if (r < 0)
1895 goto fail;
1896
f5430a3e
LP		 1897 r = dns_packet_read_memdup(p, offset + rdlength - p->rindex,
1898 &rr->rrsig.signature, &rr->rrsig.signature_size,
1899 NULL);
f1d178cc
TG		 1900
1901 if (rr->rrsig.signature_size <= 0) {
1902 /* the accepted size depends on the algorithm, but for now
1903 just ensure that the value is greater than zero */
1904 r = -EBADMSG;
1905 goto fail;
1906 }
1907
151226ab
ZJS		 1908 break;
1909
d84e543d
DM		 1910 case DNS_TYPE_NSEC: {
1911
1912 /*
e5abebab 1913 * RFC6762, section 18.14 explictly states mDNS should use name compression.
d84e543d
DM		 1914 * This contradicts RFC3845, section 2.1.1
1915 */
1916
1917 bool allow_compressed = p->protocol == DNS_PROTOCOL_MDNS;
1918
1919 r = dns_packet_read_name(p, &rr->nsec.next_domain_name, allow_compressed, NULL);
50f1e641
TG		 1920 if (r < 0)
1921 goto fail;
1922
89492aaf
TG		 1923 r = dns_packet_read_type_windows(p, &rr->nsec.types, offset + rdlength - p->rindex, NULL);
1924 if (r < 0)
1925 goto fail;
1926
09eaf68c
TG		 1927 /* We accept empty NSEC bitmaps. The bit indicating the presence of the NSEC record itself
1928 * is redundant and in e.g., RFC4956 this fact is used to define a use for NSEC records
1929 * without the NSEC bit set. */
50f1e641
TG		 1930
1931 break;
d84e543d 1932 }
5d45a880
TG		 1933 case DNS_TYPE_NSEC3: {
1934 uint8_t size;
1935
1936 r = dns_packet_read_uint8(p, &rr->nsec3.algorithm, NULL);
1937 if (r < 0)
1938 goto fail;
1939
1940 r = dns_packet_read_uint8(p, &rr->nsec3.flags, NULL);
1941 if (r < 0)
1942 goto fail;
1943
1944 r = dns_packet_read_uint16(p, &rr->nsec3.iterations, NULL);
1945 if (r < 0)
1946 goto fail;
1947
f1d178cc 1948 /* this may be zero */
5d45a880
TG		 1949 r = dns_packet_read_uint8(p, &size, NULL);
1950 if (r < 0)
1951 goto fail;
1952
f5430a3e 1953 r = dns_packet_read_memdup(p, size, &rr->nsec3.salt, &rr->nsec3.salt_size, NULL);
5d45a880
TG		 1954 if (r < 0)
1955 goto fail;
1956
5d45a880
TG		 1957 r = dns_packet_read_uint8(p, &size, NULL);
1958 if (r < 0)
1959 goto fail;
1960
f1d178cc
TG		 1961 if (size <= 0) {
1962 r = -EBADMSG;
1963 goto fail;
1964 }
1965
f5430a3e 1966 r = dns_packet_read_memdup(p, size, &rr->nsec3.next_hashed_name, &rr->nsec3.next_hashed_name_size, NULL);
5d45a880
TG		 1967 if (r < 0)
1968 goto fail;
1969
6b9308d1 1970 r = dns_packet_read_type_windows(p, &rr->nsec3.types, offset + rdlength - p->rindex, NULL);
5d45a880
TG		 1971 if (r < 0)
1972 goto fail;
1973
0bbd72b2
TG		 1974 /* empty non-terminals can have NSEC3 records, so empty bitmaps are allowed */
1975
5d45a880
TG		 1976 break;
1977 }
d75acfb0
LP		 1978
1979 case DNS_TYPE_OPT: /* we only care about the header of OPT for now. */
74b2466e 1980 default:
afbc4f26 1981 unparseable:
f5430a3e 1982 r = dns_packet_read_memdup(p, rdlength, &rr->generic.data, &rr->generic.size, NULL);
74b2466e
LP		 1983 if (r < 0)
1984 goto fail;
74b2466e
LP		 1985 break;
1986 }
1987 if (r < 0)
1988 goto fail;
1989 if (p->rindex != offset + rdlength) {
1990 r = -EBADMSG;
1991 goto fail;
1992 }
1993
1994 *ret = rr;
1995 rr = NULL;
1996
d2579eec
LP		 1997 if (ret_cache_flush)
1998 *ret_cache_flush = cache_flush;
74b2466e
LP		 1999 if (start)
2000 *start = saved_rindex;
2001
2002 return 0;
2003fail:
2004 dns_packet_rewind(p, saved_rindex);
2005 return r;
2006}
2007
c3f7000e
LP		 2008static bool opt_is_good(DnsResourceRecord *rr, bool *rfc6975) {
2009 const uint8_t* p;
2010 bool found_dau_dhu_n3u = false;
2011 size_t l;
2012
2013 /* Checks whether the specified OPT RR is well-formed and whether it contains RFC6975 data (which is not OK in
2014 * a reply). */
2015
2016 assert(rr);
2017 assert(rr->key->type == DNS_TYPE_OPT);
2018
2019 /* Check that the version is 0 */
2020 if (((rr->ttl >> 16) & UINT32_C(0xFF)) != 0)
2021 return false;
2022
2023 p = rr->opt.data;
2024 l = rr->opt.size;
2025 while (l > 0) {
2026 uint16_t option_code, option_length;
2027
2028 /* At least four bytes for OPTION-CODE and OPTION-LENGTH are required */
2029 if (l < 4U)
2030 return false;
2031
2032 option_code = unaligned_read_be16(p);
2033 option_length = unaligned_read_be16(p + 2);
2034
2035 if (l < option_length + 4U)
2036 return false;
2037
2038 /* RFC 6975 DAU, DHU or N3U fields found. */
2039 if (IN_SET(option_code, 5, 6, 7))
2040 found_dau_dhu_n3u = true;
2041
2042 p += option_length + 4U;
2043 l -= option_length + 4U;
2044 }
2045
2046 *rfc6975 = found_dau_dhu_n3u;
2047 return true;
2048}
2049
faa133f3
LP		 2050int dns_packet_extract(DnsPacket *p) {
2051 _cleanup_(dns_question_unrefp) DnsQuestion *question = NULL;
2052 _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
2053 size_t saved_rindex;
2054 unsigned n, i;
74b2466e
LP		 2055 int r;
2056
a4076574
LP		 2057 if (p->extracted)
2058 return 0;
2059
faa133f3 2060 saved_rindex = p->rindex;
322345fd
LP		 2061 dns_packet_rewind(p, DNS_PACKET_HEADER_SIZE);
2062
3cb10d3a 2063 n = DNS_PACKET_QDCOUNT(p);
faa133f3
LP		 2064 if (n > 0) {
2065 question = dns_question_new(n);
2066 if (!question) {
2067 r = -ENOMEM;
2068 goto finish;
2069 }
74b2466e 2070
faa133f3
LP		 2071 for (i = 0; i < n; i++) {
2072 _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
d2579eec 2073 bool cache_flush;
74b2466e 2074
d2579eec 2075 r = dns_packet_read_key(p, &key, &cache_flush, NULL);
faa133f3
LP		 2076 if (r < 0)
2077 goto finish;
74b2466e 2078
d2579eec
LP		 2079 if (cache_flush) {
2080 r = -EBADMSG;
2081 goto finish;
2082 }
2083
c463eb78
LP		 2084 if (!dns_type_is_valid_query(key->type)) {
2085 r = -EBADMSG;
2086 goto finish;
2087 }
2088
faa133f3
LP		 2089 r = dns_question_add(question, key);
2090 if (r < 0)
2091 goto finish;
2092 }
2093 }
322345fd 2094
faa133f3
LP		 2095 n = DNS_PACKET_RRCOUNT(p);
2096 if (n > 0) {
ebc8a106 2097 _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *previous = NULL;
c3f7000e
LP		 2098 bool bad_opt = false;
2099
faa133f3
LP		 2100 answer = dns_answer_new(n);
2101 if (!answer) {
2102 r = -ENOMEM;
2103 goto finish;
2104 }
322345fd 2105
faa133f3
LP		 2106 for (i = 0; i < n; i++) {
2107 _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
ff7febd5 2108 bool cache_flush;
322345fd 2109
ff7febd5 2110 r = dns_packet_read_rr(p, &rr, &cache_flush, NULL);
faa133f3
LP		 2111 if (r < 0)
2112 goto finish;
322345fd 2113
f57e3cd5
LP		 2114 /* Try to reduce memory usage a bit */
2115 if (previous)
2116 dns_resource_key_reduce(&rr->key, &previous->key);
2117
d75acfb0 2118 if (rr->key->type == DNS_TYPE_OPT) {
c3f7000e
LP		 2119 bool has_rfc6975;
2120
2121 if (p->opt || bad_opt) {
2122 /* Multiple OPT RRs? if so, let's ignore all, because there's something wrong
2123 * with the server, and if one is valid we wouldn't know which one. */
2124 log_debug("Multiple OPT RRs detected, ignoring all.");
2125 bad_opt = true;
2126 continue;
2127 }
e6b57b37 2128
ff7febd5 2129 if (!dns_name_is_root(DNS_RESOURCE_KEY_NAME(rr->key))) {
c3f7000e
LP		 2130 /* If the OPT RR qis not owned by the root domain, then it is bad, let's ignore
2131 * it. */
2132 log_debug("OPT RR is not owned by root domain, ignoring.");
2133 bad_opt = true;
2134 continue;
2135 }
2136
2137 if (i < DNS_PACKET_ANCOUNT(p) + DNS_PACKET_NSCOUNT(p)) {
2138 /* OPT RR is in the wrong section? Some Belkin routers do this. This is a hint
2139 * the EDNS implementation is borked, like the Belkin one is, hence ignore
2140 * it. */
2141 log_debug("OPT RR in wrong section, ignoring.");
2142 bad_opt = true;
2143 continue;
ff7febd5
LP		 2144 }
2145
c3f7000e
LP		 2146 if (!opt_is_good(rr, &has_rfc6975)) {
2147 log_debug("Malformed OPT RR, ignoring.");
2148 bad_opt = true;
2149 continue;
2150 }
e6b57b37 2151
c3f7000e 2152 if (has_rfc6975) {
ebc8a106
LP		 2153 /* If the OPT RR contains RFC6975 algorithm data, then this is indication that
2154 * the server just copied the OPT it got from us (which contained that data)
2155 * back into the reply. If so, then it doesn't properly support EDNS, as
2156 * RFC6975 makes it very clear that the algorithm data should only be contained
2157 * in questions, never in replies. Crappy Belkin routers copy the OPT data for
2158 * example, hence let's detect this so that we downgrade early. */
c3f7000e
LP		 2159 log_debug("OPT RR contained RFC6975 data, ignoring.");
2160 bad_opt = true;
2161 continue;
e6b57b37 2162 }
d75acfb0
LP		 2163
2164 p->opt = dns_resource_record_ref(rr);
2165 } else {
105e1512 2166
c3f7000e
LP		 2167 /* According to RFC 4795, section 2.9. only the RRs from the Answer section shall be
2168 * cached. Hence mark only those RRs as cacheable by default, but not the ones from the
2169 * Additional or Authority sections. */
105e1512
LP		 2170
2171 r = dns_answer_add(answer, rr, p->ifindex,
d2579eec
LP		 2172 (i < DNS_PACKET_ANCOUNT(p) ? DNS_ANSWER_CACHEABLE : 0) |
2173 (p->protocol == DNS_PROTOCOL_MDNS && !cache_flush ? DNS_ANSWER_SHARED_OWNER : 0));
d75acfb0
LP		 2174 if (r < 0)
2175 goto finish;
2176 }
ebc8a106
LP		 2177
2178 /* Remember this RR, so that we potentically can merge it's ->key object with the next RR. Note
2179 * that we only do this if we actually decided to keep the RR around. */
2180 dns_resource_record_unref(previous);
2181 previous = dns_resource_record_ref(rr);
faa133f3 2182 }
c3f7000e
LP		 2183
2184 if (bad_opt)
2185 p->opt = dns_resource_record_unref(p->opt);
322345fd
LP		 2186 }
2187
faa133f3
LP		 2188 p->question = question;
2189 question = NULL;
322345fd 2190
faa133f3
LP		 2191 p->answer = answer;
2192 answer = NULL;
322345fd 2193
a4076574
LP		 2194 p->extracted = true;
2195
faa133f3 2196 r = 0;
322345fd
LP		 2197
2198finish:
2199 p->rindex = saved_rindex;
2200 return r;
2201}
2202
8af5b883
LP		 2203int dns_packet_is_reply_for(DnsPacket *p, const DnsResourceKey *key) {
2204 int r;
2205
2206 assert(p);
2207 assert(key);
2208
2209 /* Checks if the specified packet is a reply for the specified
2210 * key and the specified key is the only one in the question
2211 * section. */
2212
2213 if (DNS_PACKET_QR(p) != 1)
2214 return 0;
2215
2216 /* Let's unpack the packet, if that hasn't happened yet. */
2217 r = dns_packet_extract(p);
2218 if (r < 0)
2219 return r;
2220
2221 if (p->question->n_keys != 1)
2222 return 0;
2223
2224 return dns_resource_key_equal(p->question->keys[0], key);
2225}
2226
74b2466e
LP		 2227static const char* const dns_rcode_table[_DNS_RCODE_MAX_DEFINED] = {
2228 [DNS_RCODE_SUCCESS] = "SUCCESS",
2229 [DNS_RCODE_FORMERR] = "FORMERR",
2230 [DNS_RCODE_SERVFAIL] = "SERVFAIL",
2231 [DNS_RCODE_NXDOMAIN] = "NXDOMAIN",
2232 [DNS_RCODE_NOTIMP] = "NOTIMP",
2233 [DNS_RCODE_REFUSED] = "REFUSED",
2234 [DNS_RCODE_YXDOMAIN] = "YXDOMAIN",
2235 [DNS_RCODE_YXRRSET] = "YRRSET",
2236 [DNS_RCODE_NXRRSET] = "NXRRSET",
2237 [DNS_RCODE_NOTAUTH] = "NOTAUTH",
2238 [DNS_RCODE_NOTZONE] = "NOTZONE",
2239 [DNS_RCODE_BADVERS] = "BADVERS",
2240 [DNS_RCODE_BADKEY] = "BADKEY",
2241 [DNS_RCODE_BADTIME] = "BADTIME",
2242 [DNS_RCODE_BADMODE] = "BADMODE",
2243 [DNS_RCODE_BADNAME] = "BADNAME",
2244 [DNS_RCODE_BADALG] = "BADALG",
2245 [DNS_RCODE_BADTRUNC] = "BADTRUNC",
2246};
2247DEFINE_STRING_TABLE_LOOKUP(dns_rcode, int);
1716f6dc
LP		 2248
2249static const char* const dns_protocol_table[_DNS_PROTOCOL_MAX] = {
2250 [DNS_PROTOCOL_DNS] = "dns",
2251 [DNS_PROTOCOL_MDNS] = "mdns",
2252 [DNS_PROTOCOL_LLMNR] = "llmnr",
2253};
2254DEFINE_STRING_TABLE_LOOKUP(dns_protocol, DnsProtocol);
Unnamed repository; edit this file 'description' to name the repository.