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