2 Unix SMB/CIFS implementation.
4 DNS server handler for queries
6 Copyright (C) 2010 Kai Blin <kai@samba.org>
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>.
23 #include "smbd/service_task.h"
24 #include "libcli/util/werror.h"
25 #include "librpc/ndr/libndr.h"
26 #include "librpc/gen_ndr/ndr_dns.h"
27 #include "librpc/gen_ndr/ndr_dnsp.h"
29 #include "param/param.h"
30 #include "dsdb/samdb/samdb.h"
31 #include "dsdb/common/util.h"
32 #include "dns_server/dns_server.h"
33 #include "libcli/dns/libdns.h"
34 #include "lib/util/util_net.h"
35 #include "lib/util/tevent_werror.h"
36 #include "auth/auth.h"
37 #include "auth/credentials/credentials.h"
38 #include "auth/gensec/gensec.h"
41 #define DBGC_CLASS DBGC_DNS
43 static WERROR create_response_rr(const struct dns_name_question *question,
44 const struct dnsp_DnssrvRpcRecord *rec,
45 struct dns_res_rec **answers, uint16_t *ancount)
47 struct dns_res_rec *ans = *answers;
48 uint16_t ai = *ancount;
56 ans[ai].rdata.cname_record = talloc_strdup(ans, rec->data.cname);
57 W_ERROR_HAVE_NO_MEMORY(ans[ai].rdata.cname_record);
60 ans[ai].rdata.ipv4_record = talloc_strdup(ans, rec->data.ipv4);
61 W_ERROR_HAVE_NO_MEMORY(ans[ai].rdata.ipv4_record);
64 ans[ai].rdata.ipv6_record = talloc_strdup(ans, rec->data.ipv6);
65 W_ERROR_HAVE_NO_MEMORY(ans[ai].rdata.ipv6_record);
68 ans[ai].rdata.ns_record = talloc_strdup(ans, rec->data.ns);
69 W_ERROR_HAVE_NO_MEMORY(ans[ai].rdata.ns_record);
72 ans[ai].rdata.srv_record.priority = rec->data.srv.wPriority;
73 ans[ai].rdata.srv_record.weight = rec->data.srv.wWeight;
74 ans[ai].rdata.srv_record.port = rec->data.srv.wPort;
75 ans[ai].rdata.srv_record.target = talloc_strdup(
76 ans, rec->data.srv.nameTarget);
77 W_ERROR_HAVE_NO_MEMORY(ans[ai].rdata.srv_record.target);
80 ans[ai].rdata.soa_record.mname = talloc_strdup(
81 ans, rec->data.soa.mname);
82 W_ERROR_HAVE_NO_MEMORY(ans[ai].rdata.soa_record.mname);
83 ans[ai].rdata.soa_record.rname = talloc_strdup(
84 ans, rec->data.soa.rname);
85 W_ERROR_HAVE_NO_MEMORY(ans[ai].rdata.soa_record.rname);
86 ans[ai].rdata.soa_record.serial = rec->data.soa.serial;
87 ans[ai].rdata.soa_record.refresh = rec->data.soa.refresh;
88 ans[ai].rdata.soa_record.retry = rec->data.soa.retry;
89 ans[ai].rdata.soa_record.expire = rec->data.soa.expire;
90 ans[ai].rdata.soa_record.minimum = rec->data.soa.minimum;
93 ans[ai].rdata.ptr_record = talloc_strdup(ans, rec->data.ptr);
96 ans[ai].rdata.mx_record.preference = rec->data.mx.wPriority;
97 ans[ai].rdata.mx_record.exchange = talloc_strdup(
98 ans, rec->data.mx.nameTarget);
99 if (ans[ai].rdata.mx_record.exchange == NULL) {
104 tmp = talloc_asprintf(ans, "\"%s\"", rec->data.txt.str[0]);
105 W_ERROR_HAVE_NO_MEMORY(tmp);
106 for (i=1; i<rec->data.txt.count; i++) {
107 tmp = talloc_asprintf_append_buffer(
108 tmp, " \"%s\"", rec->data.txt.str[i]);
109 W_ERROR_HAVE_NO_MEMORY(tmp);
111 ans[ai].rdata.txt_record.txt = tmp;
114 DEBUG(0, ("Got unhandled type %u query.\n", rec->wType));
115 return DNS_ERR(NOT_IMPLEMENTED);
118 ans[ai].name = talloc_strdup(ans, question->name);
119 W_ERROR_HAVE_NO_MEMORY(ans[ai].name);
120 ans[ai].rr_type = rec->wType;
121 ans[ai].rr_class = DNS_QCLASS_IN;
122 ans[ai].ttl = rec->dwTtlSeconds;
123 ans[ai].length = UINT16_MAX;
132 struct ask_forwarder_state {
133 struct tevent_context *ev;
135 struct dns_name_packet in_packet;
138 static void ask_forwarder_done(struct tevent_req *subreq);
140 static struct tevent_req *ask_forwarder_send(
141 TALLOC_CTX *mem_ctx, struct tevent_context *ev,
142 const char *forwarder, struct dns_name_question *question)
144 struct tevent_req *req, *subreq;
145 struct ask_forwarder_state *state;
146 struct dns_name_packet out_packet = { 0, };
148 enum ndr_err_code ndr_err;
150 req = tevent_req_create(mem_ctx, &state, struct ask_forwarder_state);
155 generate_random_buffer((uint8_t *)&state->id, sizeof(state->id));
157 if (!is_ipaddress(forwarder)) {
158 DEBUG(0, ("Invalid 'dns forwarder' setting '%s', needs to be "
159 "an IP address\n", forwarder));
160 tevent_req_werror(req, DNS_ERR(NAME_ERROR));
161 return tevent_req_post(req, ev);
164 out_packet.id = state->id;
165 out_packet.operation |= DNS_OPCODE_QUERY | DNS_FLAG_RECURSION_DESIRED;
166 out_packet.qdcount = 1;
167 out_packet.questions = question;
169 ndr_err = ndr_push_struct_blob(
170 &out_blob, state, &out_packet,
171 (ndr_push_flags_fn_t)ndr_push_dns_name_packet);
172 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
173 tevent_req_werror(req, DNS_ERR(SERVER_FAILURE));
174 return tevent_req_post(req, ev);
176 subreq = dns_udp_request_send(state, ev, forwarder, out_blob.data,
178 if (tevent_req_nomem(subreq, req)) {
179 return tevent_req_post(req, ev);
181 tevent_req_set_callback(subreq, ask_forwarder_done, req);
185 static void ask_forwarder_done(struct tevent_req *subreq)
187 struct tevent_req *req = tevent_req_callback_data(
188 subreq, struct tevent_req);
189 struct ask_forwarder_state *state = tevent_req_data(
190 req, struct ask_forwarder_state);
192 enum ndr_err_code ndr_err;
195 ret = dns_udp_request_recv(subreq, state,
196 &in_blob.data, &in_blob.length);
198 if (tevent_req_werror(req, ret)) {
202 ndr_err = ndr_pull_struct_blob(
203 &in_blob, state, &state->in_packet,
204 (ndr_pull_flags_fn_t)ndr_pull_dns_name_packet);
205 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
206 tevent_req_werror(req, DNS_ERR(SERVER_FAILURE));
209 if (state->in_packet.id != state->id) {
210 tevent_req_werror(req, DNS_ERR(NAME_ERROR));
213 tevent_req_done(req);
216 static WERROR ask_forwarder_recv(
217 struct tevent_req *req, TALLOC_CTX *mem_ctx,
218 struct dns_res_rec **answers, uint16_t *ancount,
219 struct dns_res_rec **nsrecs, uint16_t *nscount,
220 struct dns_res_rec **additional, uint16_t *arcount)
222 struct ask_forwarder_state *state = tevent_req_data(
223 req, struct ask_forwarder_state);
224 struct dns_name_packet *in_packet = &state->in_packet;
227 if (tevent_req_is_werror(req, &err)) {
231 *ancount = in_packet->ancount;
232 *answers = talloc_move(mem_ctx, &in_packet->answers);
234 *nscount = in_packet->nscount;
235 *nsrecs = talloc_move(mem_ctx, &in_packet->nsrecs);
237 *arcount = in_packet->arcount;
238 *additional = talloc_move(mem_ctx, &in_packet->additional);
243 static WERROR handle_question(struct dns_server *dns,
245 const struct dns_name_question *question,
246 struct dns_res_rec **answers, uint16_t *ancount)
248 struct dns_res_rec *ans = *answers;
251 struct dnsp_DnssrvRpcRecord *recs;
252 uint16_t rec_count, ai = *ancount;
253 struct ldb_dn *dn = NULL;
255 werror = dns_name2dn(dns, mem_ctx, question->name, &dn);
256 W_ERROR_NOT_OK_RETURN(werror);
258 werror = dns_lookup_records(dns, mem_ctx, dn, &recs, &rec_count);
259 W_ERROR_NOT_OK_RETURN(werror);
261 ans = talloc_realloc(mem_ctx, ans, struct dns_res_rec, rec_count + ai);
266 for (ri = 0; ri < rec_count; ri++) {
267 if ((recs[ri].wType == DNS_TYPE_CNAME) &&
268 ((question->question_type == DNS_QTYPE_A) ||
269 (question->question_type == DNS_QTYPE_AAAA))) {
270 struct dns_name_question *new_q =
271 talloc(mem_ctx, struct dns_name_question);
277 /* We reply with one more record, so grow the array */
278 ans = talloc_realloc(mem_ctx, ans, struct dns_res_rec,
285 /* First put in the CNAME record */
286 werror = create_response_rr(question, &recs[ri], &ans, &ai);
287 if (!W_ERROR_IS_OK(werror)) {
291 /* And then look up the name it points at.. */
293 /* First build up the new question */
294 new_q->question_type = question->question_type;
295 new_q->question_class = question->question_class;
296 if (new_q->question_type == DNS_QTYPE_A) {
297 new_q->name = talloc_strdup(new_q, recs[ri].data.ipv4);
298 } else if (new_q->question_type == DNS_QTYPE_AAAA) {
299 new_q->name = talloc_strdup(new_q, recs[ri].data.ipv6);
301 if (new_q->name == NULL) {
305 /* and then call the lookup again */
306 werror = handle_question(dns, mem_ctx, new_q, &ans, &ai);
307 if (!W_ERROR_IS_OK(werror)) {
314 if ((question->question_type != DNS_QTYPE_ALL) &&
315 (recs[ri].wType != question->question_type)) {
318 werror = create_response_rr(question, &recs[ri], &ans, &ai);
319 if (!W_ERROR_IS_OK(werror)) {
325 return DNS_ERR(NAME_ERROR);
334 static NTSTATUS create_tkey(struct dns_server *dns,
336 const char* algorithm,
337 struct dns_server_tkey **tkey)
340 struct dns_server_tkey_store *store = dns->tkeys;
341 struct dns_server_tkey *k = talloc_zero(store, struct dns_server_tkey);
344 return NT_STATUS_NO_MEMORY;
347 k->name = talloc_strdup(k, name);
349 if (k->name == NULL) {
350 return NT_STATUS_NO_MEMORY;
353 k->algorithm = talloc_strdup(k, algorithm);
354 if (k->algorithm == NULL) {
355 return NT_STATUS_NO_MEMORY;
358 status = samba_server_gensec_start(k,
359 dns->task->event_ctx,
362 dns->server_credentials,
365 if (!NT_STATUS_IS_OK(status)) {
366 DEBUG(1, ("Failed to start GENSEC server code: %s\n", nt_errstr(status)));
371 gensec_want_feature(k->gensec, GENSEC_FEATURE_SIGN);
373 status = gensec_start_mech_by_oid(k->gensec, GENSEC_OID_SPNEGO);
375 if (!NT_STATUS_IS_OK(status)) {
376 DEBUG(1, ("Failed to start GENSEC server code: %s\n",
382 if (store->tkeys[store->next_idx] != NULL) {
383 TALLOC_FREE(store->tkeys[store->next_idx]);
386 store->tkeys[store->next_idx] = k;
388 store->next_idx %= store->size;
394 static NTSTATUS accept_gss_ticket(TALLOC_CTX *mem_ctx,
395 struct dns_server *dns,
396 struct dns_server_tkey *tkey,
397 const DATA_BLOB *key,
399 uint16_t *dns_auth_error)
403 status = gensec_update(tkey->gensec, mem_ctx, dns->task->event_ctx,
406 if (NT_STATUS_EQUAL(NT_STATUS_MORE_PROCESSING_REQUIRED, status)) {
407 *dns_auth_error = DNS_RCODE_OK;
411 if (NT_STATUS_IS_OK(status)) {
413 status = gensec_session_info(tkey->gensec, tkey, &tkey->session_info);
414 if (!NT_STATUS_IS_OK(status)) {
415 *dns_auth_error = DNS_RCODE_BADKEY;
418 *dns_auth_error = DNS_RCODE_OK;
424 static WERROR handle_tkey(struct dns_server *dns,
426 const struct dns_name_packet *in,
427 struct dns_request_state *state,
428 struct dns_res_rec **answers,
431 struct dns_res_rec *in_tkey = NULL;
432 struct dns_res_rec *ret_tkey;
435 for (i = 0; i < in->arcount; i++) {
436 if (in->additional[i].rr_type == DNS_QTYPE_TKEY) {
437 in_tkey = &in->additional[i];
442 /* If this is a TKEY query, it should have a TKEY RR.
443 * Behaviour is not really specified in RFC 2930 or RFC 3645, but
444 * FORMAT_ERROR seems to be what BIND uses .*/
445 if (in_tkey == NULL) {
446 return DNS_ERR(FORMAT_ERROR);
449 ret_tkey = talloc_zero(mem_ctx, struct dns_res_rec);
450 if (ret_tkey == NULL) {
454 ret_tkey->name = talloc_strdup(ret_tkey, in_tkey->name);
455 if (ret_tkey->name == NULL) {
459 ret_tkey->rr_type = DNS_QTYPE_TKEY;
460 ret_tkey->rr_class = DNS_QCLASS_ANY;
461 ret_tkey->length = UINT16_MAX;
463 ret_tkey->rdata.tkey_record.algorithm = talloc_strdup(ret_tkey,
464 in_tkey->rdata.tkey_record.algorithm);
465 if (ret_tkey->rdata.tkey_record.algorithm == NULL) {
469 ret_tkey->rdata.tkey_record.inception = in_tkey->rdata.tkey_record.inception;
470 ret_tkey->rdata.tkey_record.expiration = in_tkey->rdata.tkey_record.expiration;
471 ret_tkey->rdata.tkey_record.mode = in_tkey->rdata.tkey_record.mode;
473 switch (in_tkey->rdata.tkey_record.mode) {
474 case DNS_TKEY_MODE_DH:
475 /* FIXME: According to RFC 2930, we MUST support this, but we don't.
476 * Still, claim it's a bad key instead of a bad mode */
477 ret_tkey->rdata.tkey_record.error = DNS_RCODE_BADKEY;
479 case DNS_TKEY_MODE_GSSAPI: {
481 struct dns_server_tkey *tkey;
485 tkey = dns_find_tkey(dns->tkeys, in->questions[0].name);
486 if (tkey != NULL && tkey->complete) {
487 /* TODO: check if the key is still valid */
488 DEBUG(1, ("Rejecting tkey negotiation for already established key\n"));
489 ret_tkey->rdata.tkey_record.error = DNS_RCODE_BADNAME;
494 status = create_tkey(dns, in->questions[0].name,
495 in_tkey->rdata.tkey_record.algorithm,
497 if (!NT_STATUS_IS_OK(status)) {
498 ret_tkey->rdata.tkey_record.error = DNS_RCODE_BADKEY;
499 return ntstatus_to_werror(status);
503 key.data = in_tkey->rdata.tkey_record.key_data;
504 key.length = in_tkey->rdata.tkey_record.key_size;
506 status = accept_gss_ticket(ret_tkey, dns, tkey, &key, &reply,
507 &ret_tkey->rdata.tkey_record.error);
508 if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
509 DEBUG(1, ("More processing required\n"));
510 ret_tkey->rdata.tkey_record.error = DNS_RCODE_BADKEY;
511 } else if (NT_STATUS_IS_OK(status)) {
512 DEBUG(1, ("Tkey handshake completed\n"));
513 ret_tkey->rdata.tkey_record.key_size = reply.length;
514 ret_tkey->rdata.tkey_record.key_data = talloc_memdup(ret_tkey,
518 state->key_name = talloc_strdup(mem_ctx, tkey->name);
519 if (state->key_name == NULL) {
523 DEBUG(1, ("GSS key negotiation returned %s\n", nt_errstr(status)));
524 ret_tkey->rdata.tkey_record.error = DNS_RCODE_BADKEY;
529 case DNS_TKEY_MODE_DELETE:
530 /* TODO: implement me */
531 DEBUG(1, ("Should delete tkey here\n"));
532 ret_tkey->rdata.tkey_record.error = DNS_RCODE_OK;
534 case DNS_TKEY_MODE_NULL:
535 case DNS_TKEY_MODE_SERVER:
536 case DNS_TKEY_MODE_CLIENT:
537 case DNS_TKEY_MODE_LAST:
538 /* We don't have to implement these, return a mode error */
539 ret_tkey->rdata.tkey_record.error = DNS_RCODE_BADMODE;
542 DEBUG(1, ("Unsupported TKEY mode %d\n",
543 in_tkey->rdata.tkey_record.mode));
552 struct dns_server_process_query_state {
553 struct dns_res_rec *answers;
555 struct dns_res_rec *nsrecs;
557 struct dns_res_rec *additional;
561 static void dns_server_process_query_got_response(struct tevent_req *subreq);
563 struct tevent_req *dns_server_process_query_send(
564 TALLOC_CTX *mem_ctx, struct tevent_context *ev,
565 struct dns_server *dns, struct dns_request_state *req_state,
566 const struct dns_name_packet *in)
568 struct tevent_req *req, *subreq;
569 struct dns_server_process_query_state *state;
571 req = tevent_req_create(mem_ctx, &state,
572 struct dns_server_process_query_state);
576 if (in->qdcount != 1) {
577 tevent_req_werror(req, DNS_ERR(FORMAT_ERROR));
578 return tevent_req_post(req, ev);
581 /* Windows returns NOT_IMPLEMENTED on this as well */
582 if (in->questions[0].question_class == DNS_QCLASS_NONE) {
583 tevent_req_werror(req, DNS_ERR(NOT_IMPLEMENTED));
584 return tevent_req_post(req, ev);
587 if (in->questions[0].question_type == DNS_QTYPE_TKEY) {
590 err = handle_tkey(dns, state, in, req_state,
591 &state->answers, &state->ancount);
592 if (tevent_req_werror(req, err)) {
593 return tevent_req_post(req, ev);
595 tevent_req_done(req);
596 return tevent_req_post(req, ev);
599 if (dns_authorative_for_zone(dns, in->questions[0].name)) {
602 req_state->flags |= DNS_FLAG_AUTHORITATIVE;
603 err = handle_question(dns, state, &in->questions[0],
604 &state->answers, &state->ancount);
605 if (tevent_req_werror(req, err)) {
606 return tevent_req_post(req, ev);
608 tevent_req_done(req);
609 return tevent_req_post(req, ev);
612 if ((req_state->flags & DNS_FLAG_RECURSION_DESIRED) &&
613 (req_state->flags & DNS_FLAG_RECURSION_AVAIL)) {
614 DEBUG(2, ("Not authoritative for '%s', forwarding\n",
615 in->questions[0].name));
617 subreq = ask_forwarder_send(
618 state, ev, lpcfg_dns_forwarder(dns->task->lp_ctx),
620 if (tevent_req_nomem(subreq, req)) {
621 return tevent_req_post(req, ev);
623 tevent_req_set_callback(
624 subreq, dns_server_process_query_got_response, req);
628 tevent_req_werror(req, DNS_ERR(NAME_ERROR));
629 return tevent_req_post(req, ev);
632 static void dns_server_process_query_got_response(struct tevent_req *subreq)
634 struct tevent_req *req = tevent_req_callback_data(
635 subreq, struct tevent_req);
636 struct dns_server_process_query_state *state = tevent_req_data(
637 req, struct dns_server_process_query_state);
640 err = ask_forwarder_recv(subreq, state,
641 &state->answers, &state->ancount,
642 &state->nsrecs, &state->nscount,
643 &state->additional, &state->arcount);
645 if (tevent_req_werror(req, err)) {
648 tevent_req_done(req);
651 WERROR dns_server_process_query_recv(
652 struct tevent_req *req, TALLOC_CTX *mem_ctx,
653 struct dns_res_rec **answers, uint16_t *ancount,
654 struct dns_res_rec **nsrecs, uint16_t *nscount,
655 struct dns_res_rec **additional, uint16_t *arcount)
657 struct dns_server_process_query_state *state = tevent_req_data(
658 req, struct dns_server_process_query_state);
661 if (tevent_req_is_werror(req, &err)) {
664 *answers = talloc_move(mem_ctx, &state->answers);
665 *ancount = state->ancount;
666 *nsrecs = talloc_move(mem_ctx, &state->nsrecs);
667 *nscount = state->nscount;
668 *additional = talloc_move(mem_ctx, &state->additional);
669 *arcount = state->arcount;