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