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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 | ||
22 | #include "utf8.h" | |
c73ce96b | 23 | #include "util.h" |
74b2466e LP |
24 | #include "resolved-dns-domain.h" |
25 | #include "resolved-dns-packet.h" | |
26 | ||
1716f6dc | 27 | int dns_packet_new(DnsPacket **ret, DnsProtocol protocol, size_t mtu) { |
74b2466e LP |
28 | DnsPacket *p; |
29 | size_t a; | |
30 | ||
31 | assert(ret); | |
32 | ||
33 | if (mtu <= 0) | |
34 | a = DNS_PACKET_SIZE_START; | |
35 | else | |
36 | a = mtu; | |
37 | ||
38 | if (a < DNS_PACKET_HEADER_SIZE) | |
39 | a = DNS_PACKET_HEADER_SIZE; | |
40 | ||
c73ce96b LP |
41 | /* round up to next page size */ |
42 | a = PAGE_ALIGN(ALIGN(sizeof(DnsPacket)) + a) - ALIGN(sizeof(DnsPacket)); | |
43 | ||
44 | /* make sure we never allocate more than useful */ | |
45 | if (a > DNS_PACKET_SIZE_MAX) | |
46 | a = DNS_PACKET_SIZE_MAX; | |
47 | ||
74b2466e LP |
48 | p = malloc0(ALIGN(sizeof(DnsPacket)) + a); |
49 | if (!p) | |
50 | return -ENOMEM; | |
51 | ||
52 | p->size = p->rindex = DNS_PACKET_HEADER_SIZE; | |
53 | p->allocated = a; | |
1716f6dc | 54 | p->protocol = protocol; |
74b2466e LP |
55 | p->n_ref = 1; |
56 | ||
57 | *ret = p; | |
58 | ||
59 | return 0; | |
60 | } | |
61 | ||
1716f6dc | 62 | int dns_packet_new_query(DnsPacket **ret, DnsProtocol protocol, size_t mtu) { |
74b2466e LP |
63 | DnsPacket *p; |
64 | DnsPacketHeader *h; | |
65 | int r; | |
66 | ||
67 | assert(ret); | |
68 | ||
1716f6dc | 69 | r = dns_packet_new(&p, protocol, mtu); |
74b2466e LP |
70 | if (r < 0) |
71 | return r; | |
72 | ||
73 | h = DNS_PACKET_HEADER(p); | |
1716f6dc | 74 | |
ea917db9 LP |
75 | if (protocol == DNS_PROTOCOL_LLMNR) |
76 | h->flags = htobe16(DNS_PACKET_MAKE_FLAGS(0 /* qr */, | |
77 | 0 /* opcode */, | |
78 | 0 /* c */, | |
79 | 0 /* tc */, | |
80 | 0 /* t */, | |
81 | 0 /* ra */, | |
82 | 0 /* ad */, | |
83 | 0 /* cd */, | |
84 | 0 /* rcode */)); | |
1716f6dc | 85 | else |
ea917db9 LP |
86 | h->flags = htobe16(DNS_PACKET_MAKE_FLAGS(0 /* qr */, |
87 | 0 /* opcode */, | |
88 | 0 /* aa */, | |
89 | 0 /* tc */, | |
90 | 1 /* rd (ask for recursion) */, | |
91 | 0 /* ra */, | |
92 | 0 /* ad */, | |
93 | 0 /* cd */, | |
94 | 0 /* rcode */)); | |
74b2466e LP |
95 | |
96 | *ret = p; | |
97 | return 0; | |
98 | } | |
99 | ||
100 | DnsPacket *dns_packet_ref(DnsPacket *p) { | |
101 | ||
102 | if (!p) | |
103 | return NULL; | |
104 | ||
105 | assert(p->n_ref > 0); | |
106 | p->n_ref++; | |
107 | return p; | |
108 | } | |
109 | ||
110 | static void dns_packet_free(DnsPacket *p) { | |
111 | char *s; | |
112 | ||
113 | assert(p); | |
114 | ||
faa133f3 LP |
115 | dns_question_unref(p->question); |
116 | dns_answer_unref(p->answer); | |
322345fd | 117 | |
74b2466e LP |
118 | while ((s = hashmap_steal_first_key(p->names))) |
119 | free(s); | |
120 | hashmap_free(p->names); | |
121 | ||
faa133f3 | 122 | free(p->_data); |
74b2466e LP |
123 | free(p); |
124 | } | |
125 | ||
126 | DnsPacket *dns_packet_unref(DnsPacket *p) { | |
127 | if (!p) | |
128 | return NULL; | |
129 | ||
130 | assert(p->n_ref > 0); | |
131 | ||
132 | if (p->n_ref == 1) | |
133 | dns_packet_free(p); | |
134 | else | |
135 | p->n_ref--; | |
136 | ||
137 | return NULL; | |
138 | } | |
139 | ||
140 | int dns_packet_validate(DnsPacket *p) { | |
141 | assert(p); | |
142 | ||
143 | if (p->size < DNS_PACKET_HEADER_SIZE) | |
144 | return -EBADMSG; | |
145 | ||
c73ce96b LP |
146 | if (p->size > DNS_PACKET_SIZE_MAX) |
147 | return -EBADMSG; | |
148 | ||
623a4c97 | 149 | return 1; |
74b2466e LP |
150 | } |
151 | ||
152 | int dns_packet_validate_reply(DnsPacket *p) { | |
74b2466e LP |
153 | int r; |
154 | ||
155 | assert(p); | |
156 | ||
157 | r = dns_packet_validate(p); | |
158 | if (r < 0) | |
159 | return r; | |
160 | ||
623a4c97 LP |
161 | if (DNS_PACKET_QR(p) != 1) |
162 | return 0; | |
163 | ||
164 | if (DNS_PACKET_OPCODE(p) != 0) | |
74b2466e LP |
165 | return -EBADMSG; |
166 | ||
ea917db9 LP |
167 | /* RFC 4795, Section 2.1.1. says to discard all replies with QDCOUNT != 1 */ |
168 | if (p->protocol == DNS_PROTOCOL_LLMNR && | |
169 | DNS_PACKET_QDCOUNT(p) != 1) | |
170 | return -EBADMSG; | |
171 | ||
623a4c97 LP |
172 | return 1; |
173 | } | |
174 | ||
175 | int dns_packet_validate_query(DnsPacket *p) { | |
176 | int r; | |
177 | ||
178 | assert(p); | |
179 | ||
180 | r = dns_packet_validate(p); | |
181 | if (r < 0) | |
182 | return r; | |
183 | ||
184 | if (DNS_PACKET_QR(p) != 0) | |
185 | return 0; | |
186 | ||
3cb10d3a | 187 | if (DNS_PACKET_OPCODE(p) != 0) |
74b2466e LP |
188 | return -EBADMSG; |
189 | ||
623a4c97 LP |
190 | if (DNS_PACKET_TC(p)) |
191 | return -EBADMSG; | |
192 | ||
ea917db9 | 193 | /* RFC 4795, Section 2.1.1. says to discard all queries with QDCOUNT != 1 */ |
623a4c97 LP |
194 | if (p->protocol == DNS_PROTOCOL_LLMNR && |
195 | DNS_PACKET_QDCOUNT(p) != 1) | |
196 | return -EBADMSG; | |
197 | ||
ea917db9 | 198 | /* RFC 4795, Section 2.1.1. says to discard all queries with ANCOUNT != 0 */ |
623a4c97 LP |
199 | if (DNS_PACKET_ANCOUNT(p) > 0) |
200 | return -EBADMSG; | |
201 | ||
ea917db9 | 202 | /* RFC 4795, Section 2.1.1. says to discard all queries with NSCOUNT != 0 */ |
623a4c97 LP |
203 | if (DNS_PACKET_NSCOUNT(p) > 0) |
204 | return -EBADMSG; | |
205 | ||
206 | return 1; | |
74b2466e LP |
207 | } |
208 | ||
209 | static int dns_packet_extend(DnsPacket *p, size_t add, void **ret, size_t *start) { | |
210 | assert(p); | |
211 | ||
c73ce96b LP |
212 | if (p->size + add > p->allocated) { |
213 | size_t a; | |
214 | ||
215 | a = PAGE_ALIGN((p->size + add) * 2); | |
216 | if (a > DNS_PACKET_SIZE_MAX) | |
217 | a = DNS_PACKET_SIZE_MAX; | |
218 | ||
219 | if (p->size + add > a) | |
220 | return -EMSGSIZE; | |
221 | ||
faa133f3 | 222 | if (p->_data) { |
c73ce96b LP |
223 | void *d; |
224 | ||
faa133f3 | 225 | d = realloc(p->_data, a); |
c73ce96b LP |
226 | if (!d) |
227 | return -ENOMEM; | |
228 | ||
faa133f3 | 229 | p->_data = d; |
c73ce96b | 230 | } else { |
faa133f3 LP |
231 | p->_data = malloc(a); |
232 | if (!p->_data) | |
c73ce96b LP |
233 | return -ENOMEM; |
234 | ||
faa133f3 LP |
235 | memcpy(p->_data, (uint8_t*) p + ALIGN(sizeof(DnsPacket)), p->size); |
236 | memzero((uint8_t*) p->_data + p->size, a - p->size); | |
c73ce96b LP |
237 | } |
238 | ||
239 | p->allocated = a; | |
240 | } | |
74b2466e LP |
241 | |
242 | if (start) | |
243 | *start = p->size; | |
244 | ||
245 | if (ret) | |
246 | *ret = (uint8_t*) DNS_PACKET_DATA(p) + p->size; | |
247 | ||
248 | p->size += add; | |
249 | return 0; | |
250 | } | |
251 | ||
252 | static void dns_packet_truncate(DnsPacket *p, size_t sz) { | |
253 | Iterator i; | |
254 | char *s; | |
255 | void *n; | |
256 | ||
257 | assert(p); | |
258 | ||
259 | if (p->size <= sz) | |
260 | return; | |
261 | ||
262 | HASHMAP_FOREACH_KEY(s, n, p->names, i) { | |
263 | ||
264 | if (PTR_TO_SIZE(n) < sz) | |
265 | continue; | |
266 | ||
267 | hashmap_remove(p->names, s); | |
268 | free(s); | |
269 | } | |
270 | ||
271 | p->size = sz; | |
272 | } | |
273 | ||
623a4c97 LP |
274 | int dns_packet_append_blob(DnsPacket *p, const void *d, size_t l, size_t *start) { |
275 | void *q; | |
276 | int r; | |
277 | ||
278 | assert(p); | |
279 | ||
280 | r = dns_packet_extend(p, l, &q, start); | |
281 | if (r < 0) | |
282 | return r; | |
283 | ||
284 | memcpy(q, d, l); | |
285 | return 0; | |
286 | } | |
287 | ||
74b2466e LP |
288 | int dns_packet_append_uint8(DnsPacket *p, uint8_t v, size_t *start) { |
289 | void *d; | |
290 | int r; | |
291 | ||
292 | assert(p); | |
293 | ||
294 | r = dns_packet_extend(p, sizeof(uint8_t), &d, start); | |
295 | if (r < 0) | |
296 | return r; | |
297 | ||
298 | ((uint8_t*) d)[0] = v; | |
299 | ||
300 | return 0; | |
301 | } | |
302 | ||
303 | int dns_packet_append_uint16(DnsPacket *p, uint16_t v, size_t *start) { | |
304 | void *d; | |
305 | int r; | |
306 | ||
307 | assert(p); | |
308 | ||
309 | r = dns_packet_extend(p, sizeof(uint16_t), &d, start); | |
310 | if (r < 0) | |
311 | return r; | |
312 | ||
313 | ((uint8_t*) d)[0] = (uint8_t) (v >> 8); | |
623a4c97 LP |
314 | ((uint8_t*) d)[1] = (uint8_t) v; |
315 | ||
316 | return 0; | |
317 | } | |
318 | ||
319 | int dns_packet_append_uint32(DnsPacket *p, uint32_t v, size_t *start) { | |
320 | void *d; | |
321 | int r; | |
322 | ||
323 | assert(p); | |
324 | ||
325 | r = dns_packet_extend(p, sizeof(uint32_t), &d, start); | |
326 | if (r < 0) | |
327 | return r; | |
328 | ||
329 | ((uint8_t*) d)[0] = (uint8_t) (v >> 24); | |
330 | ((uint8_t*) d)[1] = (uint8_t) (v >> 16); | |
331 | ((uint8_t*) d)[2] = (uint8_t) (v >> 8); | |
332 | ((uint8_t*) d)[3] = (uint8_t) v; | |
74b2466e LP |
333 | |
334 | return 0; | |
335 | } | |
336 | ||
337 | int dns_packet_append_string(DnsPacket *p, const char *s, size_t *start) { | |
338 | void *d; | |
339 | size_t l; | |
340 | int r; | |
341 | ||
342 | assert(p); | |
343 | assert(s); | |
344 | ||
345 | l = strlen(s); | |
346 | if (l > 255) | |
347 | return -E2BIG; | |
348 | ||
349 | r = dns_packet_extend(p, 1 + l, &d, start); | |
350 | if (r < 0) | |
351 | return r; | |
352 | ||
353 | ((uint8_t*) d)[0] = (uint8_t) l; | |
354 | memcpy(((uint8_t*) d) + 1, s, l); | |
355 | ||
356 | return 0; | |
357 | } | |
358 | ||
359 | int dns_packet_append_label(DnsPacket *p, const char *d, size_t l, size_t *start) { | |
360 | void *w; | |
361 | int r; | |
362 | ||
363 | assert(p); | |
364 | assert(d); | |
365 | ||
366 | if (l > DNS_LABEL_MAX) | |
367 | return -E2BIG; | |
368 | ||
369 | r = dns_packet_extend(p, 1 + l, &w, start); | |
370 | if (r < 0) | |
371 | return r; | |
372 | ||
373 | ((uint8_t*) w)[0] = (uint8_t) l; | |
374 | memcpy(((uint8_t*) w) + 1, d, l); | |
375 | ||
376 | return 0; | |
377 | } | |
378 | ||
379 | int dns_packet_append_name(DnsPacket *p, const char *name, size_t *start) { | |
380 | size_t saved_size; | |
381 | int r; | |
382 | ||
383 | assert(p); | |
384 | assert(name); | |
385 | ||
386 | saved_size = p->size; | |
387 | ||
388 | while (*name) { | |
389 | _cleanup_free_ char *s = NULL; | |
390 | char label[DNS_LABEL_MAX]; | |
391 | size_t n; | |
392 | ||
393 | n = PTR_TO_SIZE(hashmap_get(p->names, name)); | |
394 | if (n > 0) { | |
395 | assert(n < p->size); | |
396 | ||
397 | if (n < 0x4000) { | |
398 | r = dns_packet_append_uint16(p, 0xC000 | n, NULL); | |
399 | if (r < 0) | |
400 | goto fail; | |
401 | ||
402 | goto done; | |
403 | } | |
404 | } | |
405 | ||
406 | s = strdup(name); | |
407 | if (!s) { | |
408 | r = -ENOMEM; | |
409 | goto fail; | |
410 | } | |
411 | ||
412 | r = dns_label_unescape(&name, label, sizeof(label)); | |
413 | if (r < 0) | |
414 | goto fail; | |
415 | ||
416 | r = dns_packet_append_label(p, label, r, &n); | |
417 | if (r < 0) | |
418 | goto fail; | |
419 | ||
420 | r = hashmap_ensure_allocated(&p->names, dns_name_hash_func, dns_name_compare_func); | |
421 | if (r < 0) | |
422 | goto fail; | |
423 | ||
424 | r = hashmap_put(p->names, s, SIZE_TO_PTR(n)); | |
425 | if (r < 0) | |
426 | goto fail; | |
427 | ||
428 | s = NULL; | |
429 | } | |
430 | ||
431 | r = dns_packet_append_uint8(p, 0, NULL); | |
432 | if (r < 0) | |
433 | return r; | |
434 | ||
435 | done: | |
436 | if (start) | |
437 | *start = saved_size; | |
438 | ||
439 | return 0; | |
440 | ||
441 | fail: | |
442 | dns_packet_truncate(p, saved_size); | |
443 | return r; | |
444 | } | |
445 | ||
446 | int dns_packet_append_key(DnsPacket *p, const DnsResourceKey *k, size_t *start) { | |
447 | size_t saved_size; | |
448 | int r; | |
449 | ||
450 | assert(p); | |
451 | assert(k); | |
452 | ||
453 | saved_size = p->size; | |
454 | ||
faa133f3 | 455 | r = dns_packet_append_name(p, DNS_RESOURCE_KEY_NAME(k), NULL); |
74b2466e LP |
456 | if (r < 0) |
457 | goto fail; | |
458 | ||
459 | r = dns_packet_append_uint16(p, k->type, NULL); | |
460 | if (r < 0) | |
461 | goto fail; | |
462 | ||
463 | r = dns_packet_append_uint16(p, k->class, NULL); | |
464 | if (r < 0) | |
465 | goto fail; | |
466 | ||
467 | if (start) | |
468 | *start = saved_size; | |
469 | ||
470 | return 0; | |
471 | ||
472 | fail: | |
473 | dns_packet_truncate(p, saved_size); | |
474 | return r; | |
475 | } | |
476 | ||
623a4c97 LP |
477 | int dns_packet_append_rr(DnsPacket *p, const DnsResourceRecord *rr, size_t *start) { |
478 | size_t saved_size, rdlength_offset, end, rdlength; | |
479 | int r; | |
480 | ||
481 | assert(p); | |
482 | assert(rr); | |
483 | ||
484 | saved_size = p->size; | |
485 | ||
486 | r = dns_packet_append_key(p, rr->key, NULL); | |
487 | if (r < 0) | |
488 | goto fail; | |
489 | ||
490 | r = dns_packet_append_uint32(p, rr->ttl, NULL); | |
491 | if (r < 0) | |
492 | goto fail; | |
493 | ||
494 | /* Initially we write 0 here */ | |
495 | r = dns_packet_append_uint16(p, 0, &rdlength_offset); | |
496 | if (r < 0) | |
497 | goto fail; | |
498 | ||
499 | switch (rr->key->type) { | |
500 | ||
501 | case DNS_TYPE_PTR: | |
502 | case DNS_TYPE_NS: | |
503 | case DNS_TYPE_CNAME: | |
504 | r = dns_packet_append_name(p, rr->ptr.name, NULL); | |
505 | break; | |
506 | ||
507 | case DNS_TYPE_HINFO: | |
508 | r = dns_packet_append_string(p, rr->hinfo.cpu, NULL); | |
509 | if (r < 0) | |
510 | goto fail; | |
511 | ||
512 | r = dns_packet_append_string(p, rr->hinfo.os, NULL); | |
513 | break; | |
514 | ||
515 | case DNS_TYPE_A: | |
516 | r = dns_packet_append_blob(p, &rr->a.in_addr, sizeof(struct in_addr), NULL); | |
517 | break; | |
518 | ||
519 | case DNS_TYPE_AAAA: | |
520 | r = dns_packet_append_blob(p, &rr->aaaa.in6_addr, sizeof(struct in6_addr), NULL); | |
521 | break; | |
522 | ||
523 | case DNS_TYPE_SOA: | |
524 | r = dns_packet_append_name(p, rr->soa.mname, NULL); | |
525 | if (r < 0) | |
526 | goto fail; | |
527 | ||
528 | r = dns_packet_append_name(p, rr->soa.rname, NULL); | |
529 | if (r < 0) | |
530 | goto fail; | |
531 | ||
532 | r = dns_packet_append_uint32(p, rr->soa.serial, NULL); | |
533 | if (r < 0) | |
534 | goto fail; | |
535 | ||
536 | r = dns_packet_append_uint32(p, rr->soa.refresh, NULL); | |
537 | if (r < 0) | |
538 | goto fail; | |
539 | ||
540 | r = dns_packet_append_uint32(p, rr->soa.retry, NULL); | |
541 | if (r < 0) | |
542 | goto fail; | |
543 | ||
544 | r = dns_packet_append_uint32(p, rr->soa.expire, NULL); | |
545 | if (r < 0) | |
546 | goto fail; | |
547 | ||
548 | r = dns_packet_append_uint32(p, rr->soa.minimum, NULL); | |
549 | break; | |
550 | ||
551 | case DNS_TYPE_MX: | |
946c7094 ZJS |
552 | r = dns_packet_append_uint16(p, rr->mx.priority, NULL); |
553 | if (r < 0) | |
554 | goto fail; | |
555 | ||
556 | r = dns_packet_append_name(p, rr->mx.exchange, NULL); | |
557 | break; | |
558 | ||
623a4c97 LP |
559 | case DNS_TYPE_TXT: |
560 | case DNS_TYPE_SRV: | |
561 | case DNS_TYPE_DNAME: | |
562 | case DNS_TYPE_SSHFP: | |
563 | default: | |
564 | r = dns_packet_append_blob(p, rr->generic.data, rr->generic.size, NULL); | |
565 | break; | |
566 | } | |
567 | if (r < 0) | |
568 | goto fail; | |
569 | ||
570 | /* Let's calculate the actual data size and update the field */ | |
571 | rdlength = p->size - rdlength_offset - sizeof(uint16_t); | |
572 | if (rdlength > 0xFFFF) { | |
573 | r = ENOSPC; | |
574 | goto fail; | |
575 | } | |
576 | ||
577 | end = p->size; | |
578 | p->size = rdlength_offset; | |
579 | r = dns_packet_append_uint16(p, rdlength, NULL); | |
580 | if (r < 0) | |
581 | goto fail; | |
582 | p->size = end; | |
583 | ||
351e6342 LP |
584 | if (start) |
585 | *start = saved_size; | |
586 | ||
623a4c97 LP |
587 | return 0; |
588 | ||
589 | fail: | |
590 | dns_packet_truncate(p, saved_size); | |
591 | return r; | |
592 | } | |
593 | ||
594 | ||
74b2466e LP |
595 | int dns_packet_read(DnsPacket *p, size_t sz, const void **ret, size_t *start) { |
596 | assert(p); | |
597 | ||
598 | if (p->rindex + sz > p->size) | |
599 | return -EMSGSIZE; | |
600 | ||
601 | if (ret) | |
602 | *ret = (uint8_t*) DNS_PACKET_DATA(p) + p->rindex; | |
603 | ||
604 | if (start) | |
605 | *start = p->rindex; | |
606 | ||
607 | p->rindex += sz; | |
608 | return 0; | |
609 | } | |
610 | ||
8ba9fd9c | 611 | void dns_packet_rewind(DnsPacket *p, size_t idx) { |
74b2466e LP |
612 | assert(p); |
613 | assert(idx <= p->size); | |
614 | assert(idx >= DNS_PACKET_HEADER_SIZE); | |
615 | ||
616 | p->rindex = idx; | |
617 | } | |
618 | ||
623a4c97 LP |
619 | int dns_packet_read_blob(DnsPacket *p, void *d, size_t sz, size_t *start) { |
620 | const void *q; | |
621 | int r; | |
622 | ||
623 | assert(p); | |
624 | assert(d); | |
625 | ||
626 | r = dns_packet_read(p, sz, &q, start); | |
627 | if (r < 0) | |
628 | return r; | |
629 | ||
630 | memcpy(d, q, sz); | |
631 | return 0; | |
632 | } | |
633 | ||
74b2466e LP |
634 | int dns_packet_read_uint8(DnsPacket *p, uint8_t *ret, size_t *start) { |
635 | const void *d; | |
636 | int r; | |
637 | ||
638 | assert(p); | |
639 | ||
640 | r = dns_packet_read(p, sizeof(uint8_t), &d, start); | |
641 | if (r < 0) | |
642 | return r; | |
643 | ||
644 | *ret = ((uint8_t*) d)[0]; | |
645 | return 0; | |
646 | } | |
647 | ||
648 | int dns_packet_read_uint16(DnsPacket *p, uint16_t *ret, size_t *start) { | |
649 | const void *d; | |
650 | int r; | |
651 | ||
652 | assert(p); | |
653 | ||
654 | r = dns_packet_read(p, sizeof(uint16_t), &d, start); | |
655 | if (r < 0) | |
656 | return r; | |
657 | ||
658 | *ret = (((uint16_t) ((uint8_t*) d)[0]) << 8) | | |
659 | ((uint16_t) ((uint8_t*) d)[1]); | |
660 | return 0; | |
661 | } | |
662 | ||
663 | int dns_packet_read_uint32(DnsPacket *p, uint32_t *ret, size_t *start) { | |
664 | const void *d; | |
665 | int r; | |
666 | ||
667 | assert(p); | |
668 | ||
669 | r = dns_packet_read(p, sizeof(uint32_t), &d, start); | |
670 | if (r < 0) | |
671 | return r; | |
672 | ||
673 | *ret = (((uint32_t) ((uint8_t*) d)[0]) << 24) | | |
674 | (((uint32_t) ((uint8_t*) d)[1]) << 16) | | |
675 | (((uint32_t) ((uint8_t*) d)[2]) << 8) | | |
676 | ((uint32_t) ((uint8_t*) d)[3]); | |
677 | ||
678 | return 0; | |
679 | } | |
680 | ||
681 | int dns_packet_read_string(DnsPacket *p, char **ret, size_t *start) { | |
682 | size_t saved_rindex; | |
683 | const void *d; | |
684 | char *t; | |
685 | uint8_t c; | |
686 | int r; | |
687 | ||
688 | assert(p); | |
689 | ||
690 | saved_rindex = p->rindex; | |
691 | ||
692 | r = dns_packet_read_uint8(p, &c, NULL); | |
693 | if (r < 0) | |
694 | goto fail; | |
695 | ||
696 | r = dns_packet_read(p, c, &d, NULL); | |
697 | if (r < 0) | |
698 | goto fail; | |
699 | ||
700 | if (memchr(d, 0, c)) { | |
701 | r = -EBADMSG; | |
702 | goto fail; | |
703 | } | |
704 | ||
705 | t = strndup(d, c); | |
706 | if (!t) { | |
707 | r = -ENOMEM; | |
708 | goto fail; | |
709 | } | |
710 | ||
711 | if (!utf8_is_valid(t)) { | |
712 | free(t); | |
713 | r = -EBADMSG; | |
714 | goto fail; | |
715 | } | |
716 | ||
717 | *ret = t; | |
718 | ||
719 | if (start) | |
720 | *start = saved_rindex; | |
721 | ||
722 | return 0; | |
723 | ||
724 | fail: | |
725 | dns_packet_rewind(p, saved_rindex); | |
726 | return r; | |
727 | } | |
728 | ||
729 | int dns_packet_read_name(DnsPacket *p, char **_ret, size_t *start) { | |
730 | size_t saved_rindex, after_rindex = 0; | |
731 | _cleanup_free_ char *ret = NULL; | |
732 | size_t n = 0, allocated = 0; | |
733 | bool first = true; | |
734 | int r; | |
735 | ||
736 | assert(p); | |
737 | assert(_ret); | |
738 | ||
739 | saved_rindex = p->rindex; | |
740 | ||
741 | for (;;) { | |
742 | uint8_t c, d; | |
743 | ||
744 | r = dns_packet_read_uint8(p, &c, NULL); | |
745 | if (r < 0) | |
746 | goto fail; | |
747 | ||
748 | if (c == 0) | |
749 | /* End of name */ | |
750 | break; | |
751 | else if (c <= 63) { | |
752 | _cleanup_free_ char *t = NULL; | |
753 | const char *label; | |
754 | ||
755 | /* Literal label */ | |
756 | r = dns_packet_read(p, c, (const void**) &label, NULL); | |
757 | if (r < 0) | |
758 | goto fail; | |
759 | ||
760 | r = dns_label_escape(label, c, &t); | |
761 | if (r < 0) | |
762 | goto fail; | |
763 | ||
764 | if (!GREEDY_REALLOC(ret, allocated, n + !first + strlen(t) + 1)) { | |
765 | r = -ENOMEM; | |
766 | goto fail; | |
767 | } | |
768 | ||
769 | if (!first) | |
770 | ret[n++] = '.'; | |
771 | else | |
772 | first = false; | |
773 | ||
774 | memcpy(ret + n, t, c); | |
775 | n += r; | |
776 | continue; | |
777 | } else if ((c & 0xc0) == 0xc0) { | |
778 | uint16_t ptr; | |
779 | ||
780 | /* Pointer */ | |
781 | r = dns_packet_read_uint8(p, &d, NULL); | |
782 | if (r < 0) | |
783 | goto fail; | |
784 | ||
785 | ptr = (uint16_t) (c & ~0xc0) << 8 | (uint16_t) d; | |
786 | if (ptr < DNS_PACKET_HEADER_SIZE || ptr >= saved_rindex) { | |
787 | r = -EBADMSG; | |
788 | goto fail; | |
789 | } | |
790 | ||
791 | if (after_rindex == 0) | |
792 | after_rindex = p->rindex; | |
793 | ||
794 | p->rindex = ptr; | |
795 | } else | |
796 | goto fail; | |
797 | } | |
798 | ||
799 | if (!GREEDY_REALLOC(ret, allocated, n + 1)) { | |
800 | r = -ENOMEM; | |
801 | goto fail; | |
802 | } | |
803 | ||
804 | ret[n] = 0; | |
805 | ||
806 | if (after_rindex != 0) | |
807 | p->rindex= after_rindex; | |
808 | ||
809 | *_ret = ret; | |
810 | ret = NULL; | |
811 | ||
812 | if (start) | |
813 | *start = saved_rindex; | |
814 | ||
815 | return 0; | |
816 | ||
817 | fail: | |
818 | dns_packet_rewind(p, saved_rindex); | |
819 | return r; | |
820 | } | |
821 | ||
faa133f3 LP |
822 | int dns_packet_read_key(DnsPacket *p, DnsResourceKey **ret, size_t *start) { |
823 | _cleanup_free_ char *name = NULL; | |
824 | uint16_t class, type; | |
825 | DnsResourceKey *key; | |
74b2466e LP |
826 | size_t saved_rindex; |
827 | int r; | |
828 | ||
829 | assert(p); | |
830 | assert(ret); | |
831 | ||
832 | saved_rindex = p->rindex; | |
833 | ||
faa133f3 | 834 | r = dns_packet_read_name(p, &name, NULL); |
74b2466e LP |
835 | if (r < 0) |
836 | goto fail; | |
837 | ||
faa133f3 | 838 | r = dns_packet_read_uint16(p, &type, NULL); |
74b2466e LP |
839 | if (r < 0) |
840 | goto fail; | |
841 | ||
faa133f3 | 842 | r = dns_packet_read_uint16(p, &class, NULL); |
74b2466e LP |
843 | if (r < 0) |
844 | goto fail; | |
845 | ||
faa133f3 LP |
846 | key = dns_resource_key_new_consume(class, type, name); |
847 | if (!key) { | |
848 | r = -ENOMEM; | |
849 | goto fail; | |
850 | } | |
851 | ||
852 | name = NULL; | |
853 | *ret = key; | |
74b2466e LP |
854 | |
855 | if (start) | |
856 | *start = saved_rindex; | |
857 | ||
858 | return 0; | |
859 | fail: | |
860 | dns_packet_rewind(p, saved_rindex); | |
861 | return r; | |
862 | } | |
863 | ||
864 | int dns_packet_read_rr(DnsPacket *p, DnsResourceRecord **ret, size_t *start) { | |
faa133f3 LP |
865 | _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; |
866 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL; | |
74b2466e LP |
867 | size_t saved_rindex, offset; |
868 | uint16_t rdlength; | |
869 | const void *d; | |
870 | int r; | |
871 | ||
872 | assert(p); | |
873 | assert(ret); | |
874 | ||
4e0296a9 | 875 | saved_rindex = p->rindex; |
74b2466e | 876 | |
faa133f3 | 877 | r = dns_packet_read_key(p, &key, NULL); |
74b2466e LP |
878 | if (r < 0) |
879 | goto fail; | |
880 | ||
0e2bcd6a LP |
881 | if (key->class == DNS_CLASS_ANY || |
882 | key->type == DNS_TYPE_ANY) { | |
883 | r = -EBADMSG; | |
884 | goto fail; | |
885 | } | |
886 | ||
faa133f3 LP |
887 | rr = dns_resource_record_new(key); |
888 | if (!rr) { | |
889 | r = -ENOMEM; | |
890 | goto fail; | |
891 | } | |
892 | ||
74b2466e LP |
893 | r = dns_packet_read_uint32(p, &rr->ttl, NULL); |
894 | if (r < 0) | |
895 | goto fail; | |
896 | ||
897 | r = dns_packet_read_uint16(p, &rdlength, NULL); | |
898 | if (r < 0) | |
899 | goto fail; | |
900 | ||
901 | if (p->rindex + rdlength > p->size) { | |
902 | r = -EBADMSG; | |
903 | goto fail; | |
904 | } | |
905 | ||
906 | offset = p->rindex; | |
907 | ||
faa133f3 | 908 | switch (rr->key->type) { |
74b2466e LP |
909 | |
910 | case DNS_TYPE_PTR: | |
911 | case DNS_TYPE_NS: | |
912 | case DNS_TYPE_CNAME: | |
913 | r = dns_packet_read_name(p, &rr->ptr.name, NULL); | |
914 | break; | |
915 | ||
916 | case DNS_TYPE_HINFO: | |
917 | r = dns_packet_read_string(p, &rr->hinfo.cpu, NULL); | |
918 | if (r < 0) | |
919 | goto fail; | |
920 | ||
921 | r = dns_packet_read_string(p, &rr->hinfo.os, NULL); | |
922 | break; | |
923 | ||
924 | case DNS_TYPE_A: | |
623a4c97 | 925 | r = dns_packet_read_blob(p, &rr->a.in_addr, sizeof(struct in_addr), NULL); |
74b2466e LP |
926 | break; |
927 | ||
928 | case DNS_TYPE_AAAA: | |
623a4c97 | 929 | r = dns_packet_read_blob(p, &rr->aaaa.in6_addr, sizeof(struct in6_addr), NULL); |
74b2466e LP |
930 | break; |
931 | ||
7e8e0422 LP |
932 | case DNS_TYPE_SOA: |
933 | r = dns_packet_read_name(p, &rr->soa.mname, NULL); | |
934 | if (r < 0) | |
935 | goto fail; | |
936 | ||
937 | r = dns_packet_read_name(p, &rr->soa.rname, NULL); | |
938 | if (r < 0) | |
939 | goto fail; | |
940 | ||
941 | r = dns_packet_read_uint32(p, &rr->soa.serial, NULL); | |
942 | if (r < 0) | |
943 | goto fail; | |
944 | ||
945 | r = dns_packet_read_uint32(p, &rr->soa.refresh, NULL); | |
946 | if (r < 0) | |
947 | goto fail; | |
948 | ||
949 | r = dns_packet_read_uint32(p, &rr->soa.retry, NULL); | |
950 | if (r < 0) | |
951 | goto fail; | |
952 | ||
953 | r = dns_packet_read_uint32(p, &rr->soa.expire, NULL); | |
954 | if (r < 0) | |
955 | goto fail; | |
956 | ||
957 | r = dns_packet_read_uint32(p, &rr->soa.minimum, NULL); | |
958 | break; | |
959 | ||
623a4c97 | 960 | case DNS_TYPE_MX: |
946c7094 ZJS |
961 | r = dns_packet_read_uint16(p, &rr->mx.priority, NULL); |
962 | if (r < 0) | |
963 | goto fail; | |
964 | ||
965 | r = dns_packet_read_name(p, &rr->mx.exchange, NULL); | |
966 | break; | |
967 | ||
623a4c97 LP |
968 | case DNS_TYPE_TXT: |
969 | case DNS_TYPE_SRV: | |
970 | case DNS_TYPE_DNAME: | |
971 | case DNS_TYPE_SSHFP: | |
74b2466e LP |
972 | default: |
973 | r = dns_packet_read(p, rdlength, &d, NULL); | |
974 | if (r < 0) | |
975 | goto fail; | |
976 | ||
977 | rr->generic.data = memdup(d, rdlength); | |
978 | if (!rr->generic.data) { | |
979 | r = -ENOMEM; | |
980 | goto fail; | |
981 | } | |
982 | ||
983 | rr->generic.size = rdlength; | |
984 | break; | |
985 | } | |
986 | if (r < 0) | |
987 | goto fail; | |
988 | if (p->rindex != offset + rdlength) { | |
989 | r = -EBADMSG; | |
990 | goto fail; | |
991 | } | |
992 | ||
993 | *ret = rr; | |
994 | rr = NULL; | |
995 | ||
996 | if (start) | |
997 | *start = saved_rindex; | |
998 | ||
999 | return 0; | |
1000 | fail: | |
1001 | dns_packet_rewind(p, saved_rindex); | |
1002 | return r; | |
1003 | } | |
1004 | ||
faa133f3 LP |
1005 | int dns_packet_extract(DnsPacket *p) { |
1006 | _cleanup_(dns_question_unrefp) DnsQuestion *question = NULL; | |
1007 | _cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL; | |
1008 | size_t saved_rindex; | |
1009 | unsigned n, i; | |
74b2466e LP |
1010 | int r; |
1011 | ||
faa133f3 | 1012 | saved_rindex = p->rindex; |
322345fd LP |
1013 | dns_packet_rewind(p, DNS_PACKET_HEADER_SIZE); |
1014 | ||
3cb10d3a | 1015 | n = DNS_PACKET_QDCOUNT(p); |
faa133f3 LP |
1016 | if (n > 0) { |
1017 | question = dns_question_new(n); | |
1018 | if (!question) { | |
1019 | r = -ENOMEM; | |
1020 | goto finish; | |
1021 | } | |
74b2466e | 1022 | |
faa133f3 LP |
1023 | for (i = 0; i < n; i++) { |
1024 | _cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL; | |
74b2466e | 1025 | |
faa133f3 LP |
1026 | r = dns_packet_read_key(p, &key, NULL); |
1027 | if (r < 0) | |
1028 | goto finish; | |
74b2466e | 1029 | |
faa133f3 LP |
1030 | r = dns_question_add(question, key); |
1031 | if (r < 0) | |
1032 | goto finish; | |
1033 | } | |
1034 | } | |
322345fd | 1035 | |
faa133f3 LP |
1036 | n = DNS_PACKET_RRCOUNT(p); |
1037 | if (n > 0) { | |
1038 | answer = dns_answer_new(n); | |
1039 | if (!answer) { | |
1040 | r = -ENOMEM; | |
1041 | goto finish; | |
1042 | } | |
322345fd | 1043 | |
faa133f3 LP |
1044 | for (i = 0; i < n; i++) { |
1045 | _cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL; | |
322345fd | 1046 | |
faa133f3 LP |
1047 | r = dns_packet_read_rr(p, &rr, NULL); |
1048 | if (r < 0) | |
1049 | goto finish; | |
322345fd | 1050 | |
faa133f3 LP |
1051 | r = dns_answer_add(answer, rr); |
1052 | if (r < 0) | |
1053 | goto finish; | |
1054 | } | |
322345fd LP |
1055 | } |
1056 | ||
faa133f3 LP |
1057 | p->question = question; |
1058 | question = NULL; | |
322345fd | 1059 | |
faa133f3 LP |
1060 | p->answer = answer; |
1061 | answer = NULL; | |
322345fd | 1062 | |
faa133f3 | 1063 | r = 0; |
322345fd LP |
1064 | |
1065 | finish: | |
1066 | p->rindex = saved_rindex; | |
1067 | return r; | |
1068 | } | |
1069 | ||
74b2466e LP |
1070 | static const char* const dns_rcode_table[_DNS_RCODE_MAX_DEFINED] = { |
1071 | [DNS_RCODE_SUCCESS] = "SUCCESS", | |
1072 | [DNS_RCODE_FORMERR] = "FORMERR", | |
1073 | [DNS_RCODE_SERVFAIL] = "SERVFAIL", | |
1074 | [DNS_RCODE_NXDOMAIN] = "NXDOMAIN", | |
1075 | [DNS_RCODE_NOTIMP] = "NOTIMP", | |
1076 | [DNS_RCODE_REFUSED] = "REFUSED", | |
1077 | [DNS_RCODE_YXDOMAIN] = "YXDOMAIN", | |
1078 | [DNS_RCODE_YXRRSET] = "YRRSET", | |
1079 | [DNS_RCODE_NXRRSET] = "NXRRSET", | |
1080 | [DNS_RCODE_NOTAUTH] = "NOTAUTH", | |
1081 | [DNS_RCODE_NOTZONE] = "NOTZONE", | |
1082 | [DNS_RCODE_BADVERS] = "BADVERS", | |
1083 | [DNS_RCODE_BADKEY] = "BADKEY", | |
1084 | [DNS_RCODE_BADTIME] = "BADTIME", | |
1085 | [DNS_RCODE_BADMODE] = "BADMODE", | |
1086 | [DNS_RCODE_BADNAME] = "BADNAME", | |
1087 | [DNS_RCODE_BADALG] = "BADALG", | |
1088 | [DNS_RCODE_BADTRUNC] = "BADTRUNC", | |
1089 | }; | |
1090 | DEFINE_STRING_TABLE_LOOKUP(dns_rcode, int); | |
1716f6dc LP |
1091 | |
1092 | static const char* const dns_protocol_table[_DNS_PROTOCOL_MAX] = { | |
1093 | [DNS_PROTOCOL_DNS] = "dns", | |
1094 | [DNS_PROTOCOL_MDNS] = "mdns", | |
1095 | [DNS_PROTOCOL_LLMNR] = "llmnr", | |
1096 | }; | |
1097 | DEFINE_STRING_TABLE_LOOKUP(dns_protocol, DnsProtocol); |