source4/dns_server/dns_utils.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    DNS server utils
   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 "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"
  28 #include <ldb.h>
  29 #include "dsdb/samdb/samdb.h"
  30 #include "dsdb/common/util.h"
  31 #include "dns_server/dns_server.h"
  32
  33 #undef DBGC_CLASS
  34 #define DBGC_CLASS DBGC_DNS
  35
  36 uint8_t werr_to_dns_err(WERROR werr)
  37 {
  38         if (W_ERROR_EQUAL(WERR_OK, werr)) {
  39                 return DNS_RCODE_OK;
  40         } else if (W_ERROR_EQUAL(DNS_ERR(FORMAT_ERROR), werr)) {
  41                 return DNS_RCODE_FORMERR;
  42         } else if (W_ERROR_EQUAL(DNS_ERR(SERVER_FAILURE), werr)) {
  43                 return DNS_RCODE_SERVFAIL;
  44         } else if (W_ERROR_EQUAL(DNS_ERR(NAME_ERROR), werr)) {
  45                 return DNS_RCODE_NXDOMAIN;
  46         } else if (W_ERROR_EQUAL(DNS_ERR(NOT_IMPLEMENTED), werr)) {
  47                 return DNS_RCODE_NOTIMP;
  48         } else if (W_ERROR_EQUAL(DNS_ERR(REFUSED), werr)) {
  49                 return DNS_RCODE_REFUSED;
  50         } else if (W_ERROR_EQUAL(DNS_ERR(YXDOMAIN), werr)) {
  51                 return DNS_RCODE_YXDOMAIN;
  52         } else if (W_ERROR_EQUAL(DNS_ERR(YXRRSET), werr)) {
  53                 return DNS_RCODE_YXRRSET;
  54         } else if (W_ERROR_EQUAL(DNS_ERR(NXRRSET), werr)) {
  55                 return DNS_RCODE_NXRRSET;
  56         } else if (W_ERROR_EQUAL(DNS_ERR(NOTAUTH), werr)) {
  57                 return DNS_RCODE_NOTAUTH;
  58         } else if (W_ERROR_EQUAL(DNS_ERR(NOTZONE), werr)) {
  59                 return DNS_RCODE_NOTZONE;
  60         } else if (W_ERROR_EQUAL(DNS_ERR(BADKEY), werr)) {
  61                 return DNS_RCODE_BADKEY;
  62         }
  63         DEBUG(5, ("No mapping exists for %s\n", win_errstr(werr)));
  64         return DNS_RCODE_SERVFAIL;
  65 }
  66
  67 bool dns_name_match(const char *zone, const char *name, size_t *host_part_len)
  68 {
  69         size_t zl = strlen(zone);
  70         size_t nl = strlen(name);
  71         ssize_t zi, ni;
  72         static const size_t fixup = 'a' - 'A';
  73
  74         if (zl > nl) {
  75                 return false;
  76         }
  77
  78         for (zi = zl, ni = nl; zi >= 0; zi--, ni--) {
  79                 char zc = zone[zi];
  80                 char nc = name[ni];
  81
  82                 /* convert to lower case */
  83                 if (zc >= 'A' && zc <= 'Z') {
  84                         zc += fixup;
  85                 }
  86                 if (nc >= 'A' && nc <= 'Z') {
  87                         nc += fixup;
  88                 }
  89
  90                 if (zc != nc) {
  91                         return false;
  92                 }
  93         }
  94
  95         if (ni >= 0) {
  96                 if (name[ni] != '.') {
  97                         return false;
  98                 }
  99
 100                 ni--;
 101         }
 102
 103         *host_part_len = ni+1;
 104
 105         return true;
 106 }
 107
 108 /* Names are equal if they match and there's nothing left over */
 109 bool dns_name_equal(const char *name1, const char *name2)
 110 {
 111         size_t host_part_len;
 112         bool ret = dns_name_match(name1, name2, &host_part_len);
 113
 114         return ret && (host_part_len == 0);
 115 }
 116
 117 /*
 118   see if two dns records match
 119  */
 120 bool dns_records_match(struct dnsp_DnssrvRpcRecord *rec1,
 121                        struct dnsp_DnssrvRpcRecord *rec2)
 122 {
 123         bool status;
 124         int i;
 125
 126         if (rec1->wType != rec2->wType) {
 127                 return false;
 128         }
 129
 130         /* see if the data matches */
 131         switch (rec1->wType) {
 132         case DNS_TYPE_A:
 133                 return strcmp(rec1->data.ipv4, rec2->data.ipv4) == 0;
 134         case DNS_TYPE_AAAA:
 135                 return strcmp(rec1->data.ipv6, rec2->data.ipv6) == 0;
 136         case DNS_TYPE_CNAME:
 137                 return dns_name_equal(rec1->data.cname, rec2->data.cname);
 138         case DNS_TYPE_TXT:
 139                 if (rec1->data.txt.count != rec2->data.txt.count) {
 140                         return false;
 141                 }
 142                 status = true;
 143                 for (i=0; i<rec1->data.txt.count; i++) {
 144                         status = status && (strcmp(rec1->data.txt.str[i],
 145                                                 rec2->data.txt.str[i]) == 0);
 146                 }
 147                 return status;
 148         case DNS_TYPE_PTR:
 149                 return strcmp(rec1->data.ptr, rec2->data.ptr) == 0;
 150         case DNS_TYPE_NS:
 151                 return dns_name_equal(rec1->data.ns, rec2->data.ns);
 152
 153         case DNS_TYPE_SRV:
 154                 return rec1->data.srv.wPriority == rec2->data.srv.wPriority &&
 155                         rec1->data.srv.wWeight  == rec2->data.srv.wWeight &&
 156                         rec1->data.srv.wPort    == rec2->data.srv.wPort &&
 157                         dns_name_equal(rec1->data.srv.nameTarget, rec2->data.srv.nameTarget);
 158
 159         case DNS_TYPE_MX:
 160                 return rec1->data.mx.wPriority == rec2->data.mx.wPriority &&
 161                         dns_name_equal(rec1->data.mx.nameTarget, rec2->data.mx.nameTarget);
 162
 163         case DNS_TYPE_HINFO:
 164                 return strcmp(rec1->data.hinfo.cpu, rec2->data.hinfo.cpu) == 0 &&
 165                         strcmp(rec1->data.hinfo.os, rec2->data.hinfo.os) == 0;
 166
 167         case DNS_TYPE_SOA:
 168                 return dns_name_equal(rec1->data.soa.mname, rec2->data.soa.mname) &&
 169                         dns_name_equal(rec1->data.soa.rname, rec2->data.soa.rname) &&
 170                         rec1->data.soa.serial == rec2->data.soa.serial &&
 171                         rec1->data.soa.refresh == rec2->data.soa.refresh &&
 172                         rec1->data.soa.retry == rec2->data.soa.retry &&
 173                         rec1->data.soa.expire == rec2->data.soa.expire &&
 174                         rec1->data.soa.minimum == rec2->data.soa.minimum;
 175         default:
 176                 break;
 177         }
 178
 179         return false;
 180 }
 181
 182 WERROR dns_lookup_records(struct dns_server *dns,
 183                           TALLOC_CTX *mem_ctx,
 184                           struct ldb_dn *dn,
 185                           struct dnsp_DnssrvRpcRecord **records,
 186                           uint16_t *rec_count)
 187 {
 188         static const char * const attrs[] = { "dnsRecord", NULL};
 189         struct ldb_message_element *el;
 190         uint16_t ri;
 191         int ret;
 192         struct ldb_message *msg = NULL;
 193         struct dnsp_DnssrvRpcRecord *recs;
 194
 195         ret = dsdb_search_one(dns->samdb, mem_ctx, &msg, dn,
 196                               LDB_SCOPE_BASE, attrs, 0, "%s", "(objectClass=dnsNode)");
 197         if (ret != LDB_SUCCESS) {
 198                 /* TODO: we need to check if there's a glue record we need to
 199                  * create a referral to */
 200                 return DNS_ERR(NAME_ERROR);
 201         }
 202
 203         el = ldb_msg_find_element(msg, attrs[0]);
 204         if (el == NULL) {
 205                 *records = NULL;
 206                 *rec_count = 0;
 207                 return DNS_ERR(NAME_ERROR);
 208         }
 209
 210         recs = talloc_zero_array(mem_ctx, struct dnsp_DnssrvRpcRecord, el->num_values);
 211         if (recs == NULL) {
 212                 return WERR_NOMEM;
 213         }
 214         for (ri = 0; ri < el->num_values; ri++) {
 215                 struct ldb_val *v = &el->values[ri];
 216                 enum ndr_err_code ndr_err;
 217
 218                 ndr_err = ndr_pull_struct_blob(v, recs, &recs[ri],
 219                                 (ndr_pull_flags_fn_t)ndr_pull_dnsp_DnssrvRpcRecord);
 220                 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 221                         DEBUG(0, ("Failed to grab dnsp_DnssrvRpcRecord\n"));
 222                         return DNS_ERR(SERVER_FAILURE);
 223                 }
 224         }
 225         *records = recs;
 226         *rec_count = el->num_values;
 227         return WERR_OK;
 228 }
 229
 230 WERROR dns_replace_records(struct dns_server *dns,
 231                            TALLOC_CTX *mem_ctx,
 232                            struct ldb_dn *dn,
 233                            bool needs_add,
 234                            const struct dnsp_DnssrvRpcRecord *records,
 235                            uint16_t rec_count)
 236 {
 237         struct ldb_message_element *el;
 238         uint16_t i;
 239         int ret;
 240         struct ldb_message *msg = NULL;
 241
 242         msg = ldb_msg_new(mem_ctx);
 243         W_ERROR_HAVE_NO_MEMORY(msg);
 244
 245         msg->dn = dn;
 246
 247         ret = ldb_msg_add_empty(msg, "dnsRecord", LDB_FLAG_MOD_REPLACE, &el);
 248         if (ret != LDB_SUCCESS) {
 249                 return DNS_ERR(SERVER_FAILURE);
 250         }
 251
 252         el->values = talloc_zero_array(el, struct ldb_val, rec_count);
 253         if (rec_count > 0) {
 254                 W_ERROR_HAVE_NO_MEMORY(el->values);
 255         }
 256
 257         for (i = 0; i < rec_count; i++) {
 258                 static const struct dnsp_DnssrvRpcRecord zero;
 259                 struct ldb_val *v = &el->values[el->num_values];
 260                 enum ndr_err_code ndr_err;
 261
 262                 if (memcmp(&records[i], &zero, sizeof(zero)) == 0) {
 263                         continue;
 264                 }
 265                 ndr_err = ndr_push_struct_blob(v, el->values, &records[i],
 266                                 (ndr_push_flags_fn_t)ndr_push_dnsp_DnssrvRpcRecord);
 267                 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 268                         DEBUG(0, ("Failed to grab dnsp_DnssrvRpcRecord\n"));
 269                         return DNS_ERR(SERVER_FAILURE);
 270                 }
 271                 el->num_values++;
 272         }
 273
 274
 275         if (el->num_values == 0) {
 276                 if (needs_add) {
 277                         return WERR_OK;
 278                 }
 279                 /* No entries left, delete the dnsNode object */
 280                 ret = ldb_delete(dns->samdb, msg->dn);
 281                 if (ret != LDB_SUCCESS) {
 282                         DEBUG(0, ("Deleting record failed; %d\n", ret));
 283                         return DNS_ERR(SERVER_FAILURE);
 284                 }
 285                 return WERR_OK;
 286         }
 287
 288         if (needs_add) {
 289                 ret = ldb_msg_add_string(msg, "objectClass", "dnsNode");
 290                 if (ret != LDB_SUCCESS) {
 291                         return DNS_ERR(SERVER_FAILURE);
 292                 }
 293
 294                 ret = ldb_add(dns->samdb, msg);
 295                 if (ret != LDB_SUCCESS) {
 296                         return DNS_ERR(SERVER_FAILURE);
 297                 }
 298
 299                 return WERR_OK;
 300         }
 301
 302         ret = ldb_modify(dns->samdb, msg);
 303         if (ret != LDB_SUCCESS) {
 304                 return DNS_ERR(SERVER_FAILURE);
 305         }
 306
 307         return WERR_OK;
 308 }
 309
 310 bool dns_authorative_for_zone(struct dns_server *dns,
 311                               const char *name)
 312 {
 313         const struct dns_server_zone *z;
 314         size_t host_part_len = 0;
 315
 316         if (name == NULL) {
 317                 return false;
 318         }
 319
 320         if (strcmp(name, "") == 0) {
 321                 return true;
 322         }
 323         for (z = dns->zones; z != NULL; z = z->next) {
 324                 bool match;
 325
 326                 match = dns_name_match(z->name, name, &host_part_len);
 327                 if (match) {
 328                         break;
 329                 }
 330         }
 331         if (z == NULL) {
 332                 return false;
 333         }
 334
 335         return true;
 336 }
 337
 338 WERROR dns_name2dn(struct dns_server *dns,
 339                    TALLOC_CTX *mem_ctx,
 340                    const char *name,
 341                    struct ldb_dn **_dn)
 342 {
 343         struct ldb_dn *base;
 344         struct ldb_dn *dn;
 345         const struct dns_server_zone *z;
 346         size_t host_part_len = 0;
 347
 348         if (name == NULL) {
 349                 return DNS_ERR(FORMAT_ERROR);
 350         }
 351
 352         /*TODO: Check if 'name' is a valid DNS name */
 353
 354         if (strcmp(name, "") == 0) {
 355                 base = ldb_get_default_basedn(dns->samdb);
 356                 dn = ldb_dn_copy(mem_ctx, base);
 357                 ldb_dn_add_child_fmt(dn, "DC=@,DC=RootDNSServers,CN=MicrosoftDNS,CN=System");
 358                 *_dn = dn;
 359                 return WERR_OK;
 360         }
 361
 362         for (z = dns->zones; z != NULL; z = z->next) {
 363                 bool match;
 364
 365                 match = dns_name_match(z->name, name, &host_part_len);
 366                 if (match) {
 367                         break;
 368                 }
 369         }
 370
 371         if (z == NULL) {
 372                 return DNS_ERR(NAME_ERROR);
 373         }
 374
 375         if (host_part_len == 0) {
 376                 dn = ldb_dn_copy(mem_ctx, z->dn);
 377                 ldb_dn_add_child_fmt(dn, "DC=@");
 378                 *_dn = dn;
 379                 return WERR_OK;
 380         }
 381
 382         dn = ldb_dn_copy(mem_ctx, z->dn);
 383         ldb_dn_add_child_fmt(dn, "DC=%*.*s", (int)host_part_len, (int)host_part_len, name);
 384         *_dn = dn;
 385         return WERR_OK;
 386 }
 387
 388 WERROR dns_generate_options(struct dns_server *dns,
 389                             TALLOC_CTX *mem_ctx,
 390                             struct dns_res_rec **options)
 391 {
 392         struct dns_res_rec *o;
 393
 394         o = talloc_zero(mem_ctx, struct dns_res_rec);
 395         if (o == NULL) {
 396                 return WERR_NOMEM;
 397         }
 398         o->name = '\0';
 399         o->rr_type = DNS_QTYPE_OPT;
 400         /* This is ugly, but RFC2671 wants the payload size in this field */
 401         o->rr_class = (enum dns_qclass) dns->max_payload;
 402         o->ttl = 0;
 403         o->length = 0;
 404
 405         *options = o;
 406         return WERR_OK;
 407 }