source4/dns_server/dns_update.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    DNS server handler for update requests
   5
   6    Copyright (C) 2010 Kai Blin  <kai@samba.org>
   7
   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.
  12
  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.
  17
  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/>.
  20 */
  21
  22 #include "includes.h"
  23 #include "libcli/util/ntstatus.h"
  24 #include "librpc/ndr/libndr.h"
  25 #include "librpc/gen_ndr/ndr_dns.h"
  26 #include "librpc/gen_ndr/ndr_dnsp.h"
  27 #include <ldb.h>
  28 #include "dsdb/samdb/samdb.h"
  29 #include "dsdb/common/util.h"
  30 #include "dns_server/dns_server.h"
  31
  32 static WERROR dns_rr_to_dnsp(TALLOC_CTX *mem_ctx,
  33                              const struct dns_res_rec *rrec,
  34                              struct dnsp_DnssrvRpcRecord *r);
  35
  36 static WERROR check_one_prerequisite(struct dns_server *dns,
  37                                      TALLOC_CTX *mem_ctx,
  38                                      const struct dns_name_question *zone,
  39                                      const struct dns_res_rec *pr,
  40                                      bool *final_result)
  41 {
  42         bool match;
  43         WERROR werror;
  44         struct ldb_dn *dn;
  45         uint16_t i;
  46         bool found = false;
  47         struct dnsp_DnssrvRpcRecord *rec = NULL;
  48         struct dnsp_DnssrvRpcRecord *ans;
  49         uint16_t acount;
  50
  51         size_t host_part_len = 0;
  52
  53         *final_result = true;
  54
  55         if (pr->ttl != 0) {
  56                 return DNS_ERR(FORMAT_ERROR);
  57         }
  58
  59         match = dns_name_match(zone->name, pr->name, &host_part_len);
  60         if (!match) {
  61                 return DNS_ERR(NOTZONE);
  62         }
  63
  64         werror = dns_name2dn(dns, mem_ctx, pr->name, &dn);
  65         W_ERROR_NOT_OK_RETURN(werror);
  66
  67         if (pr->rr_class == DNS_QCLASS_ANY) {
  68
  69                 if (pr->length != 0) {
  70                         return DNS_ERR(FORMAT_ERROR);
  71                 }
  72
  73
  74                 if (pr->rr_type == DNS_QTYPE_ALL) {
  75                         /*
  76                          */
  77                         werror = dns_lookup_records(dns, mem_ctx, dn, &ans, &acount);
  78                         W_ERROR_NOT_OK_RETURN(werror);
  79
  80                         if (acount == 0) {
  81                                 return DNS_ERR(NAME_ERROR);
  82                         }
  83                 } else {
  84                         /*
  85                          */
  86                         werror = dns_lookup_records(dns, mem_ctx, dn, &ans, &acount);
  87                         if (W_ERROR_EQUAL(werror, DNS_ERR(NAME_ERROR))) {
  88                                 return DNS_ERR(NXRRSET);
  89                         }
  90                         W_ERROR_NOT_OK_RETURN(werror);
  91
  92                         for (i = 0; i < acount; i++) {
  93                                 if (ans[i].wType == pr->rr_type) {
  94                                         found = true;
  95                                         break;
  96                                 }
  97                         }
  98                         if (!found) {
  99                                 return DNS_ERR(NXRRSET);
 100                         }
 101                 }
 102
 103                 /*
 104                  * RFC2136 3.2.5 doesn't actually mention the need to return
 105                  * OK here, but otherwise we'd always return a FORMAT_ERROR
 106                  * later on. This also matches Microsoft DNS behavior.
 107                  */
 108                 return WERR_OK;
 109         }
 110
 111         if (pr->rr_class == DNS_QCLASS_NONE) {
 112                 if (pr->length != 0) {
 113                         return DNS_ERR(FORMAT_ERROR);
 114                 }
 115
 116                 if (pr->rr_type == DNS_QTYPE_ALL) {
 117                         /*
 118                          */
 119                         werror = dns_lookup_records(dns, mem_ctx, dn, &ans, &acount);
 120                         if (W_ERROR_EQUAL(werror, WERR_OK)) {
 121                                 return DNS_ERR(YXDOMAIN);
 122                         }
 123                 } else {
 124                         /*
 125                          */
 126                         werror = dns_lookup_records(dns, mem_ctx, dn, &ans, &acount);
 127                         if (W_ERROR_EQUAL(werror, DNS_ERR(NAME_ERROR))) {
 128                                 werror = WERR_OK;
 129                                 ans = NULL;
 130                                 acount = 0;
 131                         }
 132
 133                         for (i = 0; i < acount; i++) {
 134                                 if (ans[i].wType == pr->rr_type) {
 135                                         found = true;
 136                                         break;
 137                                 }
 138                         }
 139                         if (found) {
 140                                 return DNS_ERR(YXRRSET);
 141                         }
 142                 }
 143
 144                 /*
 145                  * RFC2136 3.2.5 doesn't actually mention the need to return
 146                  * OK here, but otherwise we'd always return a FORMAT_ERROR
 147                  * later on. This also matches Microsoft DNS behavior.
 148                  */
 149                 return WERR_OK;
 150         }
 151
 152         if (pr->rr_class != zone->question_class) {
 153                 return DNS_ERR(FORMAT_ERROR);
 154         }
 155
 156         *final_result = false;
 157
 158         werror = dns_lookup_records(dns, mem_ctx, dn, &ans, &acount);
 159         if (W_ERROR_EQUAL(werror, DNS_ERR(NAME_ERROR))) {
 160                 return DNS_ERR(NXRRSET);
 161         }
 162         W_ERROR_NOT_OK_RETURN(werror);
 163
 164         rec = talloc_zero(mem_ctx, struct dnsp_DnssrvRpcRecord);
 165         W_ERROR_HAVE_NO_MEMORY(rec);
 166
 167         werror = dns_rr_to_dnsp(rec, pr, rec);
 168         W_ERROR_NOT_OK_RETURN(werror);
 169
 170         for (i = 0; i < acount; i++) {
 171                 if (dns_records_match(rec, &ans[i])) {
 172                         found = true;
 173                         break;
 174                 }
 175         }
 176
 177         if (!found) {
 178                 return DNS_ERR(NXRRSET);
 179         }
 180
 181         return WERR_OK;
 182 }
 183
 184 static WERROR check_prerequisites(struct dns_server *dns,
 185                                   TALLOC_CTX *mem_ctx,
 186                                   const struct dns_name_question *zone,
 187                                   const struct dns_res_rec *prereqs, uint16_t count)
 188 {
 189         uint16_t i;
 190         WERROR final_error = WERR_OK;
 191
 192         for (i = 0; i < count; i++) {
 193                 bool final;
 194                 WERROR werror;
 195
 196                 werror = check_one_prerequisite(dns, mem_ctx, zone,
 197                                                 &prereqs[i], &final);
 198                 if (!W_ERROR_IS_OK(werror)) {
 199                         if (final) {
 200                                 return werror;
 201                         }
 202                         if (W_ERROR_IS_OK(final_error)) {
 203                                 final_error = werror;
 204                         }
 205                 }
 206         }
 207
 208         if (!W_ERROR_IS_OK(final_error)) {
 209                 return final_error;
 210         }
 211
 212         return WERR_OK;
 213 }
 214
 215 static WERROR update_prescan(const struct dns_name_question *zone,
 216                              const struct dns_res_rec *updates, uint16_t count)
 217 {
 218         const struct dns_res_rec *r;
 219         uint16_t i;
 220         size_t host_part_len;
 221         bool match;
 222
 223         for (i = 0; i < count; i++) {
 224                 r = &updates[i];
 225                 match = dns_name_match(zone->name, r->name, &host_part_len);
 226                 if (!match) {
 227                         return DNS_ERR(NOTZONE);
 228                 }
 229                 if (zone->question_class == r->rr_class) {
 230                         if (r->rr_type == DNS_QTYPE_ALL) {
 231                                 return DNS_ERR(FORMAT_ERROR);
 232                         }
 233                         if (r->rr_type == DNS_QTYPE_AXFR) {
 234                                 return DNS_ERR(FORMAT_ERROR);
 235                         }
 236                         if (r->rr_type == DNS_QTYPE_MAILB) {
 237                                 return DNS_ERR(FORMAT_ERROR);
 238                         }
 239                         if (r->rr_type == DNS_QTYPE_MAILA) {
 240                                 return DNS_ERR(FORMAT_ERROR);
 241                         }
 242                 } else if (r->rr_class == DNS_QCLASS_ANY) {
 243                         if (r->ttl != 0) {
 244                                 return DNS_ERR(FORMAT_ERROR);
 245                         }
 246                         if (r->length != 0) {
 247                                 return DNS_ERR(FORMAT_ERROR);
 248                         }
 249                         if (r->rr_type == DNS_QTYPE_AXFR) {
 250                                 return DNS_ERR(FORMAT_ERROR);
 251                         }
 252                         if (r->rr_type == DNS_QTYPE_MAILB) {
 253                                 return DNS_ERR(FORMAT_ERROR);
 254                         }
 255                         if (r->rr_type == DNS_QTYPE_MAILA) {
 256                                 return DNS_ERR(FORMAT_ERROR);
 257                         }
 258                 } else if (r->rr_class == DNS_QCLASS_NONE) {
 259                         if (r->ttl != 0) {
 260                                 return DNS_ERR(FORMAT_ERROR);
 261                         }
 262                         if (r->rr_type == DNS_QTYPE_ALL) {
 263                                 return DNS_ERR(FORMAT_ERROR);
 264                         }
 265                         if (r->rr_type == DNS_QTYPE_AXFR) {
 266                                 return DNS_ERR(FORMAT_ERROR);
 267                         }
 268                         if (r->rr_type == DNS_QTYPE_MAILB) {
 269                                 return DNS_ERR(FORMAT_ERROR);
 270                         }
 271                         if (r->rr_type == DNS_QTYPE_MAILA) {
 272                                 return DNS_ERR(FORMAT_ERROR);
 273                         }
 274                 } else {
 275                         return DNS_ERR(FORMAT_ERROR);
 276                 }
 277         }
 278         return WERR_OK;
 279 }
 280
 281 static WERROR dns_rr_to_dnsp(TALLOC_CTX *mem_ctx,
 282                              const struct dns_res_rec *rrec,
 283                              struct dnsp_DnssrvRpcRecord *r)
 284 {
 285         if (rrec->rr_type == DNS_QTYPE_ALL) {
 286                 return DNS_ERR(FORMAT_ERROR);
 287         }
 288
 289         ZERO_STRUCTP(r);
 290
 291         r->wType = rrec->rr_type;
 292         r->dwTtlSeconds = rrec->ttl;
 293         r->rank = DNS_RANK_ZONE;
 294         /* TODO: Autogenerate this somehow */
 295         r->dwSerial = 110;
 296
 297         /* If we get QCLASS_ANY, we're done here */
 298         if (rrec->rr_class == DNS_QCLASS_ANY) {
 299                 goto done;
 300         }
 301
 302         switch(rrec->rr_type) {
 303         case DNS_QTYPE_A:
 304                 r->data.ipv4 = talloc_strdup(mem_ctx, rrec->rdata.ipv4_record);
 305                 W_ERROR_HAVE_NO_MEMORY(r->data.ipv4);
 306                 break;
 307         case DNS_QTYPE_AAAA:
 308                 r->data.ipv6 = talloc_strdup(mem_ctx, rrec->rdata.ipv6_record);
 309                 W_ERROR_HAVE_NO_MEMORY(r->data.ipv6);
 310                 break;
 311         case DNS_QTYPE_NS:
 312                 r->data.ns = talloc_strdup(mem_ctx, rrec->rdata.ns_record);
 313                 W_ERROR_HAVE_NO_MEMORY(r->data.ns);
 314                 break;
 315         case DNS_QTYPE_CNAME:
 316                 r->data.cname = talloc_strdup(mem_ctx, rrec->rdata.cname_record);
 317                 W_ERROR_HAVE_NO_MEMORY(r->data.cname);
 318                 break;
 319         case DNS_QTYPE_SRV:
 320                 r->data.srv.wPriority = rrec->rdata.srv_record.priority;
 321                 r->data.srv.wWeight = rrec->rdata.srv_record.weight;
 322                 r->data.srv.wPort = rrec->rdata.srv_record.port;
 323                 r->data.srv.nameTarget = talloc_strdup(mem_ctx,
 324                                 rrec->rdata.srv_record.target);
 325                 W_ERROR_HAVE_NO_MEMORY(r->data.srv.nameTarget);
 326                 break;
 327         case DNS_QTYPE_MX:
 328                 r->data.mx.wPriority = rrec->rdata.mx_record.preference;
 329                 r->data.mx.nameTarget = talloc_strdup(mem_ctx,
 330                                 rrec->rdata.mx_record.exchange);
 331                 W_ERROR_HAVE_NO_MEMORY(r->data.mx.nameTarget);
 332                 break;
 333         case DNS_QTYPE_TXT:
 334                 r->data.txt = talloc_strdup(mem_ctx, rrec->rdata.txt_record.txt);
 335                 W_ERROR_HAVE_NO_MEMORY(r->data.txt);
 336                 break;
 337         default:
 338                 DEBUG(0, ("Got a qytpe of %d\n", rrec->rr_type));
 339                 return DNS_ERR(NOT_IMPLEMENTED);
 340         }
 341
 342 done:
 343
 344         return WERR_OK;
 345 }
 346
 347 WERROR dns_server_process_update(struct dns_server *dns,
 348                                  TALLOC_CTX *mem_ctx,
 349                                  struct dns_name_packet *in,
 350                                  struct dns_res_rec **prereqs,    uint16_t *prereq_count,
 351                                  struct dns_res_rec **updates,    uint16_t *update_count,
 352                                  struct dns_res_rec **additional, uint16_t *arcount)
 353 {
 354         struct dns_name_question *zone;
 355         const struct dns_server_zone *z;
 356         size_t host_part_len = 0;
 357         WERROR werror = DNS_ERR(NOT_IMPLEMENTED);
 358         bool update_allowed = false;
 359
 360         if (in->qdcount != 1) {
 361                 return DNS_ERR(FORMAT_ERROR);
 362         }
 363
 364         zone = &in->questions[0];
 365
 366         if (zone->question_class != DNS_QCLASS_IN &&
 367             zone->question_class != DNS_QCLASS_ANY) {
 368                 return DNS_ERR(NOT_IMPLEMENTED);
 369         }
 370
 371         if (zone->question_type != DNS_QTYPE_SOA) {
 372                 return DNS_ERR(FORMAT_ERROR);
 373         }
 374
 375         DEBUG(0, ("Got a dns update request.\n"));
 376
 377         for (z = dns->zones; z != NULL; z = z->next) {
 378                 bool match;
 379
 380                 match = dns_name_match(z->name, zone->name, &host_part_len);
 381                 if (match) {
 382                         break;
 383                 }
 384         }
 385
 386         if (z == NULL) {
 387                 return DNS_ERR(NOTAUTH);
 388         }
 389
 390         if (host_part_len != 0) {
 391                 /* TODO: We need to delegate this one */
 392                 return DNS_ERR(NOT_IMPLEMENTED);
 393         }
 394
 395         *prereq_count = in->ancount;
 396         *prereqs = in->answers;
 397         werror = check_prerequisites(dns, mem_ctx, in->questions, *prereqs,
 398                                      *prereq_count);
 399         W_ERROR_NOT_OK_RETURN(werror);
 400
 401         /* TODO: Check if update is allowed, we probably want "always",
 402          * key-based GSSAPI, key-based bind-style TSIG and "never" as
 403          * smb.conf options. */
 404         if (!update_allowed) {
 405                 return DNS_ERR(REFUSED);
 406         }
 407
 408         *update_count = in->nscount;
 409         *updates = in->nsrecs;
 410         werror = update_prescan(in->questions, *updates, *update_count);
 411         W_ERROR_NOT_OK_RETURN(werror);
 412
 413         return werror;
 414 }