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                         /*TODO: also check for AXFR,MAILA,MAILB  */
 231                         if (r->rr_type == DNS_QTYPE_ALL) {
 232                                 return DNS_ERR(FORMAT_ERROR);
 233                         }
 234                 } else if (r->rr_class == DNS_QCLASS_ANY) {
 235                         if (r->ttl != 0 || r->length != 0) {
 236                                 return DNS_ERR(FORMAT_ERROR);
 237                         }
 238                 } else if (r->rr_class == DNS_QCLASS_NONE) {
 239                         if (r->ttl != 0 || r->rr_type == DNS_QTYPE_ALL) {
 240                                 return DNS_ERR(FORMAT_ERROR);
 241                         }
 242                 } else {
 243                         return DNS_ERR(FORMAT_ERROR);
 244                 }
 245         }
 246         return WERR_OK;
 247 }
 248
 249 static WERROR dns_rr_to_dnsp(TALLOC_CTX *mem_ctx,
 250                              const struct dns_res_rec *rrec,
 251                              struct dnsp_DnssrvRpcRecord *r)
 252 {
 253         if (rrec->rr_type == DNS_QTYPE_ALL) {
 254                 return DNS_ERR(FORMAT_ERROR);
 255         }
 256
 257         ZERO_STRUCTP(r);
 258
 259         r->wType = rrec->rr_type;
 260         r->dwTtlSeconds = rrec->ttl;
 261         r->rank = DNS_RANK_ZONE;
 262         /* TODO: Autogenerate this somehow */
 263         r->dwSerial = 110;
 264
 265         /* If we get QCLASS_ANY, we're done here */
 266         if (rrec->rr_class == DNS_QCLASS_ANY) {
 267                 goto done;
 268         }
 269
 270         switch(rrec->rr_type) {
 271         case DNS_QTYPE_A:
 272                 r->data.ipv4 = talloc_strdup(mem_ctx, rrec->rdata.ipv4_record);
 273                 W_ERROR_HAVE_NO_MEMORY(r->data.ipv4);
 274                 break;
 275         case DNS_QTYPE_AAAA:
 276                 r->data.ipv6 = talloc_strdup(mem_ctx, rrec->rdata.ipv6_record);
 277                 W_ERROR_HAVE_NO_MEMORY(r->data.ipv6);
 278                 break;
 279         case DNS_QTYPE_NS:
 280                 r->data.ns = talloc_strdup(mem_ctx, rrec->rdata.ns_record);
 281                 W_ERROR_HAVE_NO_MEMORY(r->data.ns);
 282                 break;
 283         case DNS_QTYPE_CNAME:
 284                 r->data.cname = talloc_strdup(mem_ctx, rrec->rdata.cname_record);
 285                 W_ERROR_HAVE_NO_MEMORY(r->data.cname);
 286                 break;
 287         case DNS_QTYPE_SRV:
 288                 r->data.srv.wPriority = rrec->rdata.srv_record.priority;
 289                 r->data.srv.wWeight = rrec->rdata.srv_record.weight;
 290                 r->data.srv.wPort = rrec->rdata.srv_record.port;
 291                 r->data.srv.nameTarget = talloc_strdup(mem_ctx,
 292                                 rrec->rdata.srv_record.target);
 293                 W_ERROR_HAVE_NO_MEMORY(r->data.srv.nameTarget);
 294                 break;
 295         case DNS_QTYPE_MX:
 296                 r->data.mx.wPriority = rrec->rdata.mx_record.preference;
 297                 r->data.mx.nameTarget = talloc_strdup(mem_ctx,
 298                                 rrec->rdata.mx_record.exchange);
 299                 W_ERROR_HAVE_NO_MEMORY(r->data.mx.nameTarget);
 300                 break;
 301         case DNS_QTYPE_TXT:
 302                 r->data.txt = talloc_strdup(mem_ctx, rrec->rdata.txt_record.txt);
 303                 W_ERROR_HAVE_NO_MEMORY(r->data.txt);
 304                 break;
 305         default:
 306                 DEBUG(0, ("Got a qytpe of %d\n", rrec->rr_type));
 307                 return DNS_ERR(NOT_IMPLEMENTED);
 308         }
 309
 310 done:
 311
 312         return WERR_OK;
 313 }
 314
 315 WERROR dns_server_process_update(struct dns_server *dns,
 316                                  TALLOC_CTX *mem_ctx,
 317                                  struct dns_name_packet *in,
 318                                  struct dns_res_rec **prereqs,    uint16_t *prereq_count,
 319                                  struct dns_res_rec **updates,    uint16_t *update_count,
 320                                  struct dns_res_rec **additional, uint16_t *arcount)
 321 {
 322         struct dns_name_question *zone;
 323         const struct dns_server_zone *z;
 324         size_t host_part_len = 0;
 325         WERROR werror = DNS_ERR(NOT_IMPLEMENTED);
 326         bool update_allowed = false;
 327
 328         if (in->qdcount != 1) {
 329                 return DNS_ERR(FORMAT_ERROR);
 330         }
 331
 332         zone = &in->questions[0];
 333
 334         if (zone->question_class != DNS_QCLASS_IN &&
 335             zone->question_class != DNS_QCLASS_ANY) {
 336                 return DNS_ERR(NOT_IMPLEMENTED);
 337         }
 338
 339         if (zone->question_type != DNS_QTYPE_SOA) {
 340                 return DNS_ERR(FORMAT_ERROR);
 341         }
 342
 343         DEBUG(0, ("Got a dns update request.\n"));
 344
 345         for (z = dns->zones; z != NULL; z = z->next) {
 346                 bool match;
 347
 348                 match = dns_name_match(z->name, zone->name, &host_part_len);
 349                 if (match) {
 350                         break;
 351                 }
 352         }
 353
 354         if (z == NULL) {
 355                 return DNS_ERR(NOTAUTH);
 356         }
 357
 358         if (host_part_len != 0) {
 359                 /* TODO: We need to delegate this one */
 360                 return DNS_ERR(NOT_IMPLEMENTED);
 361         }
 362
 363         *prereq_count = in->ancount;
 364         *prereqs = in->answers;
 365         werror = check_prerequisites(dns, mem_ctx, in->questions, *prereqs,
 366                                      *prereq_count);
 367         W_ERROR_NOT_OK_RETURN(werror);
 368
 369         /* TODO: Check if update is allowed, we probably want "always",
 370          * key-based GSSAPI, key-based bind-style TSIG and "never" as
 371          * smb.conf options. */
 372         if (!update_allowed) {
 373                 return DNS_ERR(REFUSED);
 374         }
 375
 376         werror = update_prescan(in->questions, *updates, *update_count);
 377         W_ERROR_NOT_OK_RETURN(werror);
 378
 379         return werror;
 380 }