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(WERR_DNS_ERROR_NAME_DOES_NOT_EXIST, werr)) {
  47                 return DNS_RCODE_NXDOMAIN;
  48         } else if (W_ERROR_EQUAL(DNS_ERR(NOT_IMPLEMENTED), werr)) {
  49                 return DNS_RCODE_NOTIMP;
  50         } else if (W_ERROR_EQUAL(DNS_ERR(REFUSED), werr)) {
  51                 return DNS_RCODE_REFUSED;
  52         } else if (W_ERROR_EQUAL(DNS_ERR(YXDOMAIN), werr)) {
  53                 return DNS_RCODE_YXDOMAIN;
  54         } else if (W_ERROR_EQUAL(DNS_ERR(YXRRSET), werr)) {
  55                 return DNS_RCODE_YXRRSET;
  56         } else if (W_ERROR_EQUAL(DNS_ERR(NXRRSET), werr)) {
  57                 return DNS_RCODE_NXRRSET;
  58         } else if (W_ERROR_EQUAL(DNS_ERR(NOTAUTH), werr)) {
  59                 return DNS_RCODE_NOTAUTH;
  60         } else if (W_ERROR_EQUAL(DNS_ERR(NOTZONE), werr)) {
  61                 return DNS_RCODE_NOTZONE;
  62         } else if (W_ERROR_EQUAL(DNS_ERR(BADKEY), werr)) {
  63                 return DNS_RCODE_BADKEY;
  64         }
  65         DEBUG(5, ("No mapping exists for %s\n", win_errstr(werr)));
  66         return DNS_RCODE_SERVFAIL;
  67 }
  68
  69 bool dns_name_match(const char *zone, const char *name, size_t *host_part_len)
  70 {
  71         size_t zl = strlen(zone);
  72         size_t nl = strlen(name);
  73         ssize_t zi, ni;
  74         static const size_t fixup = 'a' - 'A';
  75
  76         if (zl > nl) {
  77                 return false;
  78         }
  79
  80         for (zi = zl, ni = nl; zi >= 0; zi--, ni--) {
  81                 char zc = zone[zi];
  82                 char nc = name[ni];
  83
  84                 /* convert to lower case */
  85                 if (zc >= 'A' && zc <= 'Z') {
  86                         zc += fixup;
  87                 }
  88                 if (nc >= 'A' && nc <= 'Z') {
  89                         nc += fixup;
  90                 }
  91
  92                 if (zc != nc) {
  93                         return false;
  94                 }
  95         }
  96
  97         if (ni >= 0) {
  98                 if (name[ni] != '.') {
  99                         return false;
 100                 }
 101
 102                 ni--;
 103         }
 104
 105         *host_part_len = ni+1;
 106
 107         return true;
 108 }
 109
 110 /* Names are equal if they match and there's nothing left over */
 111 bool dns_name_equal(const char *name1, const char *name2)
 112 {
 113         size_t host_part_len;
 114         bool ret = dns_name_match(name1, name2, &host_part_len);
 115
 116         return ret && (host_part_len == 0);
 117 }
 118
 119 /*
 120   see if two dns records match
 121  */
 122 bool dns_records_match(struct dnsp_DnssrvRpcRecord *rec1,
 123                        struct dnsp_DnssrvRpcRecord *rec2)
 124 {
 125         bool status;
 126         int i;
 127
 128         if (rec1->wType != rec2->wType) {
 129                 return false;
 130         }
 131
 132         /* see if the data matches */
 133         switch (rec1->wType) {
 134         case DNS_TYPE_A:
 135                 return strcmp(rec1->data.ipv4, rec2->data.ipv4) == 0;
 136         case DNS_TYPE_AAAA:
 137                 return strcmp(rec1->data.ipv6, rec2->data.ipv6) == 0;
 138         case DNS_TYPE_CNAME:
 139                 return dns_name_equal(rec1->data.cname, rec2->data.cname);
 140         case DNS_TYPE_TXT:
 141                 if (rec1->data.txt.count != rec2->data.txt.count) {
 142                         return false;
 143                 }
 144                 status = true;
 145                 for (i=0; i<rec1->data.txt.count; i++) {
 146                         status = status && (strcmp(rec1->data.txt.str[i],
 147                                                 rec2->data.txt.str[i]) == 0);
 148                 }
 149                 return status;
 150         case DNS_TYPE_PTR:
 151                 return strcmp(rec1->data.ptr, rec2->data.ptr) == 0;
 152         case DNS_TYPE_NS:
 153                 return dns_name_equal(rec1->data.ns, rec2->data.ns);
 154
 155         case DNS_TYPE_SRV:
 156                 return rec1->data.srv.wPriority == rec2->data.srv.wPriority &&
 157                         rec1->data.srv.wWeight  == rec2->data.srv.wWeight &&
 158                         rec1->data.srv.wPort    == rec2->data.srv.wPort &&
 159                         dns_name_equal(rec1->data.srv.nameTarget, rec2->data.srv.nameTarget);
 160
 161         case DNS_TYPE_MX:
 162                 return rec1->data.mx.wPriority == rec2->data.mx.wPriority &&
 163                         dns_name_equal(rec1->data.mx.nameTarget, rec2->data.mx.nameTarget);
 164
 165         case DNS_TYPE_HINFO:
 166                 return strcmp(rec1->data.hinfo.cpu, rec2->data.hinfo.cpu) == 0 &&
 167                         strcmp(rec1->data.hinfo.os, rec2->data.hinfo.os) == 0;
 168
 169         case DNS_TYPE_SOA:
 170                 return dns_name_equal(rec1->data.soa.mname, rec2->data.soa.mname) &&
 171                         dns_name_equal(rec1->data.soa.rname, rec2->data.soa.rname) &&
 172                         rec1->data.soa.serial == rec2->data.soa.serial &&
 173                         rec1->data.soa.refresh == rec2->data.soa.refresh &&
 174                         rec1->data.soa.retry == rec2->data.soa.retry &&
 175                         rec1->data.soa.expire == rec2->data.soa.expire &&
 176                         rec1->data.soa.minimum == rec2->data.soa.minimum;
 177         default:
 178                 break;
 179         }
 180
 181         return false;
 182 }
 183
 184 WERROR dns_lookup_records(struct dns_server *dns,
 185                           TALLOC_CTX *mem_ctx,
 186                           struct ldb_dn *dn,
 187                           struct dnsp_DnssrvRpcRecord **records,
 188                           uint16_t *rec_count)
 189 {
 190         static const char * const attrs[] = { "dnsRecord", NULL};
 191         struct ldb_message_element *el;
 192         uint16_t ri;
 193         int ret;
 194         struct ldb_message *msg = NULL;
 195         struct dnsp_DnssrvRpcRecord *recs;
 196
 197         ret = dsdb_search_one(dns->samdb, mem_ctx, &msg, dn,
 198                               LDB_SCOPE_BASE, attrs, 0, "%s", "(objectClass=dnsNode)");
 199         if (ret != LDB_SUCCESS) {
 200                 /* TODO: we need to check if there's a glue record we need to
 201                  * create a referral to */
 202                 return DNS_ERR(NAME_ERROR);
 203         }
 204
 205         el = ldb_msg_find_element(msg, attrs[0]);
 206         if (el == NULL) {
 207                 *records = NULL;
 208                 *rec_count = 0;
 209                 return DNS_ERR(NAME_ERROR);
 210         }
 211
 212         recs = talloc_zero_array(mem_ctx, struct dnsp_DnssrvRpcRecord, el->num_values);
 213         if (recs == NULL) {
 214                 return WERR_NOMEM;
 215         }
 216         for (ri = 0; ri < el->num_values; ri++) {
 217                 struct ldb_val *v = &el->values[ri];
 218                 enum ndr_err_code ndr_err;
 219
 220                 ndr_err = ndr_pull_struct_blob(v, recs, &recs[ri],
 221                                 (ndr_pull_flags_fn_t)ndr_pull_dnsp_DnssrvRpcRecord);
 222                 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 223                         DEBUG(0, ("Failed to grab dnsp_DnssrvRpcRecord\n"));
 224                         return DNS_ERR(SERVER_FAILURE);
 225                 }
 226         }
 227         *records = recs;
 228         *rec_count = el->num_values;
 229         return WERR_OK;
 230 }
 231
 232 WERROR dns_replace_records(struct dns_server *dns,
 233                            TALLOC_CTX *mem_ctx,
 234                            struct ldb_dn *dn,
 235                            bool needs_add,
 236                            const struct dnsp_DnssrvRpcRecord *records,
 237                            uint16_t rec_count)
 238 {
 239         struct ldb_message_element *el;
 240         uint16_t i;
 241         int ret;
 242         struct ldb_message *msg = NULL;
 243
 244         msg = ldb_msg_new(mem_ctx);
 245         W_ERROR_HAVE_NO_MEMORY(msg);
 246
 247         msg->dn = dn;
 248
 249         ret = ldb_msg_add_empty(msg, "dnsRecord", LDB_FLAG_MOD_REPLACE, &el);
 250         if (ret != LDB_SUCCESS) {
 251                 return DNS_ERR(SERVER_FAILURE);
 252         }
 253
 254         el->values = talloc_zero_array(el, struct ldb_val, rec_count);
 255         if (rec_count > 0) {
 256                 W_ERROR_HAVE_NO_MEMORY(el->values);
 257         }
 258
 259         for (i = 0; i < rec_count; i++) {
 260                 static const struct dnsp_DnssrvRpcRecord zero;
 261                 struct ldb_val *v = &el->values[el->num_values];
 262                 enum ndr_err_code ndr_err;
 263
 264                 if (memcmp(&records[i], &zero, sizeof(zero)) == 0) {
 265                         continue;
 266                 }
 267                 ndr_err = ndr_push_struct_blob(v, el->values, &records[i],
 268                                 (ndr_push_flags_fn_t)ndr_push_dnsp_DnssrvRpcRecord);
 269                 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 270                         DEBUG(0, ("Failed to grab dnsp_DnssrvRpcRecord\n"));
 271                         return DNS_ERR(SERVER_FAILURE);
 272                 }
 273                 el->num_values++;
 274         }
 275
 276
 277         if (el->num_values == 0) {
 278                 if (needs_add) {
 279                         return WERR_OK;
 280                 }
 281                 /* No entries left, delete the dnsNode object */
 282                 ret = ldb_delete(dns->samdb, msg->dn);
 283                 if (ret != LDB_SUCCESS) {
 284                         DEBUG(0, ("Deleting record failed; %d\n", ret));
 285                         return DNS_ERR(SERVER_FAILURE);
 286                 }
 287                 return WERR_OK;
 288         }
 289
 290         if (needs_add) {
 291                 ret = ldb_msg_add_string(msg, "objectClass", "dnsNode");
 292                 if (ret != LDB_SUCCESS) {
 293                         return DNS_ERR(SERVER_FAILURE);
 294                 }
 295
 296                 ret = ldb_add(dns->samdb, msg);
 297                 if (ret != LDB_SUCCESS) {
 298                         return DNS_ERR(SERVER_FAILURE);
 299                 }
 300
 301                 return WERR_OK;
 302         }
 303
 304         ret = ldb_modify(dns->samdb, msg);
 305         if (ret != LDB_SUCCESS) {
 306                 return DNS_ERR(SERVER_FAILURE);
 307         }
 308
 309         return WERR_OK;
 310 }
 311
 312 bool dns_authorative_for_zone(struct dns_server *dns,
 313                               const char *name)
 314 {
 315         const struct dns_server_zone *z;
 316         size_t host_part_len = 0;
 317
 318         if (name == NULL) {
 319                 return false;
 320         }
 321
 322         if (strcmp(name, "") == 0) {
 323                 return true;
 324         }
 325         for (z = dns->zones; z != NULL; z = z->next) {
 326                 bool match;
 327
 328                 match = dns_name_match(z->name, name, &host_part_len);
 329                 if (match) {
 330                         break;
 331                 }
 332         }
 333         if (z == NULL) {
 334                 return false;
 335         }
 336
 337         return true;
 338 }
 339
 340 WERROR dns_name2dn(struct dns_server *dns,
 341                    TALLOC_CTX *mem_ctx,
 342                    const char *name,
 343                    struct ldb_dn **_dn)
 344 {
 345         struct ldb_dn *base;
 346         struct ldb_dn *dn;
 347         const struct dns_server_zone *z;
 348         size_t host_part_len = 0;
 349
 350         if (name == NULL) {
 351                 return DNS_ERR(FORMAT_ERROR);
 352         }
 353
 354         /*TODO: Check if 'name' is a valid DNS name */
 355
 356         if (strcmp(name, "") == 0) {
 357                 base = ldb_get_default_basedn(dns->samdb);
 358                 dn = ldb_dn_copy(mem_ctx, base);
 359                 ldb_dn_add_child_fmt(dn, "DC=@,DC=RootDNSServers,CN=MicrosoftDNS,CN=System");
 360                 *_dn = dn;
 361                 return WERR_OK;
 362         }
 363
 364         for (z = dns->zones; z != NULL; z = z->next) {
 365                 bool match;
 366
 367                 match = dns_name_match(z->name, name, &host_part_len);
 368                 if (match) {
 369                         break;
 370                 }
 371         }
 372
 373         if (z == NULL) {
 374                 return DNS_ERR(NAME_ERROR);
 375         }
 376
 377         if (host_part_len == 0) {
 378                 dn = ldb_dn_copy(mem_ctx, z->dn);
 379                 ldb_dn_add_child_fmt(dn, "DC=@");
 380                 *_dn = dn;
 381                 return WERR_OK;
 382         }
 383
 384         dn = ldb_dn_copy(mem_ctx, z->dn);
 385         ldb_dn_add_child_fmt(dn, "DC=%*.*s", (int)host_part_len, (int)host_part_len, name);
 386         *_dn = dn;
 387         return WERR_OK;
 388 }
 389
 390 WERROR dns_generate_options(struct dns_server *dns,
 391                             TALLOC_CTX *mem_ctx,
 392                             struct dns_res_rec **options)
 393 {
 394         struct dns_res_rec *o;
 395
 396         o = talloc_zero(mem_ctx, struct dns_res_rec);
 397         if (o == NULL) {
 398                 return WERR_NOMEM;
 399         }
 400         o->name = '\0';
 401         o->rr_type = DNS_QTYPE_OPT;
 402         /* This is ugly, but RFC2671 wants the payload size in this field */
 403         o->rr_class = (enum dns_qclass) dns->max_payload;
 404         o->ttl = 0;
 405         o->length = 0;
 406
 407         *options = o;
 408         return WERR_OK;
 409 }