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