source4/dns_server/dnsserver_common.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    DNS server utils
   5
   6    Copyright (C) 2010 Kai Blin
   7    Copyright (C) 2014 Stefan Metzmacher
   8    Copyright (C) 2015 Andrew Bartlett
   9
  10    This program is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 3 of the License, or
  13    (at your option) any later version.
  14
  15    This program is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18    GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  22 */
  23
  24 #include "includes.h"
  25 #include "libcli/util/ntstatus.h"
  26 #include "libcli/util/werror.h"
  27 #include "librpc/ndr/libndr.h"
  28 #include "librpc/gen_ndr/ndr_dns.h"
  29 #include "librpc/gen_ndr/ndr_dnsp.h"
  30 #include <ldb.h>
  31 #include "dsdb/samdb/samdb.h"
  32 #include "dsdb/common/util.h"
  33 #include "dns_server/dnsserver_common.h"
  34 #include "lib/util/dlinklist.h"
  35
  36 #undef DBGC_CLASS
  37 #define DBGC_CLASS DBGC_DNS
  38
  39 uint8_t werr_to_dns_err(WERROR werr)
  40 {
  41         if (W_ERROR_EQUAL(WERR_OK, werr)) {
  42                 return DNS_RCODE_OK;
  43         } else if (W_ERROR_EQUAL(DNS_ERR(FORMAT_ERROR), werr)) {
  44                 return DNS_RCODE_FORMERR;
  45         } else if (W_ERROR_EQUAL(DNS_ERR(SERVER_FAILURE), werr)) {
  46                 return DNS_RCODE_SERVFAIL;
  47         } else if (W_ERROR_EQUAL(DNS_ERR(NAME_ERROR), werr)) {
  48                 return DNS_RCODE_NXDOMAIN;
  49         } else if (W_ERROR_EQUAL(WERR_DNS_ERROR_NAME_DOES_NOT_EXIST, werr)) {
  50                 return DNS_RCODE_NXDOMAIN;
  51         } else if (W_ERROR_EQUAL(DNS_ERR(NOT_IMPLEMENTED), werr)) {
  52                 return DNS_RCODE_NOTIMP;
  53         } else if (W_ERROR_EQUAL(DNS_ERR(REFUSED), werr)) {
  54                 return DNS_RCODE_REFUSED;
  55         } else if (W_ERROR_EQUAL(DNS_ERR(YXDOMAIN), werr)) {
  56                 return DNS_RCODE_YXDOMAIN;
  57         } else if (W_ERROR_EQUAL(DNS_ERR(YXRRSET), werr)) {
  58                 return DNS_RCODE_YXRRSET;
  59         } else if (W_ERROR_EQUAL(DNS_ERR(NXRRSET), werr)) {
  60                 return DNS_RCODE_NXRRSET;
  61         } else if (W_ERROR_EQUAL(DNS_ERR(NOTAUTH), werr)) {
  62                 return DNS_RCODE_NOTAUTH;
  63         } else if (W_ERROR_EQUAL(DNS_ERR(NOTZONE), werr)) {
  64                 return DNS_RCODE_NOTZONE;
  65         } else if (W_ERROR_EQUAL(DNS_ERR(BADKEY), werr)) {
  66                 return DNS_RCODE_BADKEY;
  67         }
  68         DEBUG(5, ("No mapping exists for %s\n", win_errstr(werr)));
  69         return DNS_RCODE_SERVFAIL;
  70 }
  71
  72 WERROR dns_common_extract(struct ldb_context *samdb,
  73                           const struct ldb_message_element *el,
  74                           TALLOC_CTX *mem_ctx,
  75                           struct dnsp_DnssrvRpcRecord **records,
  76                           uint16_t *num_records)
  77 {
  78         uint16_t ri;
  79         struct dnsp_DnssrvRpcRecord *recs;
  80
  81         *records = NULL;
  82         *num_records = 0;
  83
  84         recs = talloc_zero_array(mem_ctx, struct dnsp_DnssrvRpcRecord,
  85                                  el->num_values);
  86         if (recs == NULL) {
  87                 return WERR_NOT_ENOUGH_MEMORY;
  88         }
  89         for (ri = 0; ri < el->num_values; ri++) {
  90                 bool am_rodc;
  91                 int ret;
  92                 const char *dnsHostName = NULL;
  93                 struct ldb_val *v = &el->values[ri];
  94                 enum ndr_err_code ndr_err;
  95                 ndr_err = ndr_pull_struct_blob(v, recs, &recs[ri],
  96                                 (ndr_pull_flags_fn_t)ndr_pull_dnsp_DnssrvRpcRecord);
  97                 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
  98                         TALLOC_FREE(recs);
  99                         DEBUG(0, ("Failed to grab dnsp_DnssrvRpcRecord\n"));
 100                         return DNS_ERR(SERVER_FAILURE);
 101                 }
 102
 103                 /*
 104                  * In AD, except on an RODC (where we should list a random RWDC,
 105                  * we should over-stamp the MNAME with our own hostname
 106                  */
 107                 if (recs[ri].wType != DNS_TYPE_SOA) {
 108                         continue;
 109                 }
 110
 111                 ret = samdb_rodc(samdb, &am_rodc);
 112                 if (ret != LDB_SUCCESS) {
 113                         DEBUG(0, ("Failed to confirm we are not an RODC: %s\n",
 114                                   ldb_errstring(samdb)));
 115                         return DNS_ERR(SERVER_FAILURE);
 116                 }
 117
 118                 if (am_rodc) {
 119                         continue;
 120                 }
 121
 122                 ret = samdb_dns_host_name(samdb, &dnsHostName);
 123                 if (ret != LDB_SUCCESS || dnsHostName == NULL) {
 124                         DEBUG(0, ("Failed to get dnsHostName from rootDSE"));
 125                         return DNS_ERR(SERVER_FAILURE);
 126                 }
 127
 128                 recs[ri].data.soa.mname = talloc_strdup(recs, dnsHostName);
 129         }
 130
 131         *records = recs;
 132         *num_records = el->num_values;
 133         return WERR_OK;
 134 }
 135
 136 /*
 137  * Lookup a DNS record, performing an exact match.
 138  * i.e. DNS wild card records are not considered.
 139  */
 140 WERROR dns_common_lookup(struct ldb_context *samdb,
 141                          TALLOC_CTX *mem_ctx,
 142                          struct ldb_dn *dn,
 143                          struct dnsp_DnssrvRpcRecord **records,
 144                          uint16_t *num_records,
 145                          bool *tombstoned)
 146 {
 147         static const char * const attrs[] = {
 148                 "dnsRecord",
 149                 "dNSTombstoned",
 150                 NULL
 151         };
 152         int ret;
 153         WERROR werr;
 154         struct ldb_message *msg = NULL;
 155         struct ldb_message_element *el;
 156
 157         *records = NULL;
 158         *num_records = 0;
 159
 160         if (tombstoned != NULL) {
 161                 *tombstoned = false;
 162                 ret = dsdb_search_one(samdb, mem_ctx, &msg, dn,
 163                         LDB_SCOPE_BASE, attrs, 0,
 164                         "(objectClass=dnsNode)");
 165         } else {
 166                 ret = dsdb_search_one(samdb, mem_ctx, &msg, dn,
 167                         LDB_SCOPE_BASE, attrs, 0,
 168                         "(&(objectClass=dnsNode)(!(dNSTombstoned=TRUE)))");
 169         }
 170         if (ret == LDB_ERR_NO_SUCH_OBJECT) {
 171                 return WERR_DNS_ERROR_NAME_DOES_NOT_EXIST;
 172         }
 173         if (ret != LDB_SUCCESS) {
 174                 /* TODO: we need to check if there's a glue record we need to
 175                  * create a referral to */
 176                 return DNS_ERR(NAME_ERROR);
 177         }
 178
 179         if (tombstoned != NULL) {
 180                 *tombstoned = ldb_msg_find_attr_as_bool(msg,
 181                                         "dNSTombstoned", false);
 182         }
 183
 184         el = ldb_msg_find_element(msg, "dnsRecord");
 185         if (el == NULL) {
 186                 TALLOC_FREE(msg);
 187                 /*
 188                  * records produced by older Samba releases
 189                  * keep dnsNode objects without dnsRecord and
 190                  * without setting dNSTombstoned=TRUE.
 191                  *
 192                  * We just pretend they're tombstones.
 193                  */
 194                 if (tombstoned != NULL) {
 195                         struct dnsp_DnssrvRpcRecord *recs;
 196                         recs = talloc_array(mem_ctx,
 197                                             struct dnsp_DnssrvRpcRecord,
 198                                             1);
 199                         if (recs == NULL) {
 200                                 return WERR_NOT_ENOUGH_MEMORY;
 201                         }
 202                         recs[0] = (struct dnsp_DnssrvRpcRecord) {
 203                                 .wType = DNS_TYPE_TOMBSTONE,
 204                                 /*
 205                                  * A value of timestamp != 0
 206                                  * indicated that the object was already
 207                                  * a tombstone, this will be used
 208                                  * in dns_common_replace()
 209                                  */
 210                                 .data.timestamp = 1,
 211                         };
 212
 213                         *tombstoned = true;
 214                         *records = recs;
 215                         *num_records = 1;
 216                         return WERR_OK;
 217                 } else {
 218                         /*
 219                          * Because we are not looking for a tombstone
 220                          * in this codepath, we just pretend it does
 221                          * not exist at all.
 222                          */
 223                         return WERR_DNS_ERROR_NAME_DOES_NOT_EXIST;
 224                 }
 225         }
 226
 227         werr = dns_common_extract(samdb, el, mem_ctx, records, num_records);
 228         TALLOC_FREE(msg);
 229         if (!W_ERROR_IS_OK(werr)) {
 230                 return werr;
 231         }
 232
 233         return WERR_OK;
 234 }
 235
 236 /*
 237  * Build an ldb_parse_tree node for an equality check
 238  *
 239  * Note: name is assumed to have been validated by dns_name_check
 240  *       so will be zero terminated and of a reasonable size.
 241  */
 242 static struct ldb_parse_tree *build_equality_operation(
 243         TALLOC_CTX *mem_ctx,
 244         bool add_asterix,     /* prepend an '*' to the name          */
 245         const uint8_t *name,  /* the value being matched             */
 246         const char *attr,     /* the attribute to check name against */
 247         size_t size)          /* length of name                      */
 248 {
 249
 250         struct ldb_parse_tree *el = NULL;  /* Equality node being built */
 251         struct ldb_val *value = NULL;      /* Value the attr will be compared
 252                                               with */
 253         size_t length = 0;                 /* calculated length of the value
 254                                               including option '*' prefix and
 255                                               '\0' string terminator */
 256
 257         el = talloc(mem_ctx, struct ldb_parse_tree);
 258         if (el == NULL) {
 259                 DBG_ERR("Unable to allocate ldb_parse_tree\n");
 260                 return NULL;
 261         }
 262
 263         el->operation = LDB_OP_EQUALITY;
 264         el->u.equality.attr = talloc_strdup(mem_ctx, attr);
 265         value = &el->u.equality.value;
 266         length = (add_asterix) ? size + 2 : size + 1;
 267         value->data = talloc_zero_array(el, uint8_t, length);
 268         if (el == NULL) {
 269                 DBG_ERR("Unable to allocate value->data\n");
 270                 TALLOC_FREE(el);
 271                 return NULL;
 272         }
 273
 274         value->length = length;
 275         if (add_asterix) {
 276                 value->data[0] = '*';
 277                 memcpy(&value->data[1], name, size);
 278         } else {
 279                 memcpy(value->data, name, size);
 280         }
 281         return el;
 282 }
 283
 284 /*
 285  * Determine the number of levels in name
 286  * essentially the number of '.'s in the name + 1
 287  *
 288  * name is assumed to have been validated by dns_name_check
 289  */
 290 static unsigned int number_of_labels(const struct ldb_val *name) {
 291         int x  = 0;
 292         unsigned int labels = 1;
 293         for (x = 0; x < name->length; x++) {
 294                 if (name->data[x] == '.') {
 295                         labels++;
 296                 }
 297         }
 298         return labels;
 299 }
 300 /*
 301  * Build a query that matches the target name, and any possible
 302  * DNS wild card entries
 303  *
 304  * Builds a parse tree equivalent to the example query.
 305  *
 306  * x.y.z -> (|(name=x.y.z)(name=\2a.y.z)(name=\2a.z)(name=\2a))
 307  *
 308  * Returns NULL if unable to build the query.
 309  *
 310  * The first component of the DN is assumed to be the name being looked up
 311  * and also that it has been validated by dns_name_check
 312  *
 313  */
 314 #define BASE "(&(objectClass=dnsNode)(!(dNSTombstoned=TRUE))(|(a=b)(c=d)))"
 315 static struct ldb_parse_tree *build_wildcard_query(
 316         TALLOC_CTX *mem_ctx,
 317         struct ldb_dn *dn)
 318 {
 319         const struct ldb_val *name = NULL;            /* The DNS name being
 320                                                          queried */
 321         const char *attr = NULL;                      /* The attribute name */
 322         struct ldb_parse_tree *query = NULL;          /* The constructed query
 323                                                          parse tree*/
 324         struct ldb_parse_tree *wildcard_query = NULL; /* The parse tree for the
 325                                                          name and wild card
 326                                                          entries */
 327         int labels = 0;         /* The number of labels in the name */
 328
 329         attr = ldb_dn_get_rdn_name(dn);
 330         if (attr == NULL) {
 331                 DBG_ERR("Unable to get rdn_name\n");
 332                 return NULL;
 333         }
 334
 335         name = ldb_dn_get_rdn_val(dn);
 336         if (name == NULL) {
 337                 DBG_ERR("Unable to get domain name value\n");
 338                 return NULL;
 339         }
 340         labels = number_of_labels(name);
 341
 342         query = ldb_parse_tree(mem_ctx, BASE);
 343         if (query == NULL) {
 344                 DBG_ERR("Unable to parse query %s\n", BASE);
 345                 return NULL;
 346         }
 347
 348         /*
 349          * The 3rd element of BASE is a place holder which is replaced with
 350          * the actual wild card query
 351          */
 352         wildcard_query = query->u.list.elements[2];
 353         TALLOC_FREE(wildcard_query->u.list.elements);
 354
 355         wildcard_query->u.list.num_elements = labels + 1;
 356         wildcard_query->u.list.elements = talloc_array(
 357                 wildcard_query,
 358                 struct ldb_parse_tree *,
 359                 labels + 1);
 360         /*
 361          * Build the wild card query
 362          */
 363         {
 364                 int x = 0;   /* current character in the name               */
 365                 int l = 0;   /* current equality operator index in elements */
 366                 struct ldb_parse_tree *el = NULL; /* Equality operator being
 367                                                      built */
 368                 bool add_asterix = true;  /* prepend an '*' to the value    */
 369                 for (l = 0, x = 0; l < labels && x < name->length; l++) {
 370                         unsigned int size = name->length - x;
 371                         add_asterix = (name->data[x] == '.');
 372                         el = build_equality_operation(
 373                                 mem_ctx,
 374                                 add_asterix,
 375                                 &name->data[x],
 376                                 attr,
 377                                 size);
 378                         if (el == NULL) {
 379                                 return NULL;  /* Reason will have been logged */
 380                         }
 381                         wildcard_query->u.list.elements[l] = el;
 382
 383                         /* skip to the start of the next label */
 384                         for (;x < name->length && name->data[x] != '.'; x++);
 385                 }
 386
 387                 /* Add the base level "*" only query */
 388                 el = build_equality_operation(mem_ctx, true, NULL, attr, 0);
 389                 if (el == NULL) {
 390                         TALLOC_FREE(query);
 391                         return NULL;  /* Reason will have been logged */
 392                 }
 393                 wildcard_query->u.list.elements[l] = el;
 394         }
 395         return query;
 396 }
 397
 398 /*
 399  * Scan the list of records matching a dns wildcard query and return the
 400  * best match.
 401  *
 402  * The best match is either an exact name match, or the longest wild card
 403  * entry returned
 404  *
 405  * i.e. name = a.b.c candidates *.b.c, *.c,        - *.b.c would be selected
 406  *      name = a.b.c candidates a.b.c, *.b.c, *.c  - a.b.c would be selected
 407  */
 408 static struct ldb_message *get_best_match(struct ldb_dn *dn,
 409                                           struct ldb_result *result)
 410 {
 411         int matched = 0;    /* Index of the current best match in result */
 412         size_t length = 0;  /* The length of the current candidate       */
 413         const struct ldb_val *target = NULL;    /* value we're looking for */
 414         const struct ldb_val *candidate = NULL; /* current candidate value */
 415         int x = 0;
 416
 417         target = ldb_dn_get_rdn_val(dn);
 418         for(x = 0; x < result->count; x++) {
 419                 candidate = ldb_dn_get_rdn_val(result->msgs[x]->dn);
 420                 if (strncasecmp((char *) target->data,
 421                                 (char *) candidate->data,
 422                                 target->length) == 0) {
 423                         /* Exact match stop searching and return */
 424                         return result->msgs[x];
 425                 }
 426                 if (candidate->length > length) {
 427                         matched = x;
 428                         length  = candidate->length;
 429                 }
 430         }
 431         return result->msgs[matched];
 432 }
 433
 434 /*
 435  * Look up a DNS entry, if an exact match does not exist, return the
 436  * closest matching DNS wildcard entry if available
 437  *
 438  * Returns: LDB_ERR_NO_SUCH_OBJECT     If no matching record exists
 439  *          LDB_ERR_OPERATIONS_ERROR   If the query fails
 440  *          LDB_SUCCESS                If a matching record was retrieved
 441  *
 442  */
 443 static int dns_wildcard_lookup(struct ldb_context *samdb,
 444                                TALLOC_CTX *mem_ctx,
 445                                struct ldb_dn *dn,
 446                                struct ldb_message **msg)
 447 {
 448         static const char * const attrs[] = {
 449                 "dnsRecord",
 450                 "dNSTombstoned",
 451                 NULL
 452         };
 453         struct ldb_dn *parent = NULL;     /* The parent dn                    */
 454         struct ldb_result *result = NULL; /* Results of the search            */
 455         int ret;                          /* Return code                      */
 456         struct ldb_parse_tree *query = NULL; /* The query to run              */
 457         struct ldb_request *request = NULL;  /* LDB request for the query op  */
 458         struct ldb_message *match = NULL;    /* the best matching DNS record  */
 459         TALLOC_CTX *frame = talloc_stackframe();
 460
 461         parent = ldb_dn_get_parent(frame, dn);
 462         if (parent == NULL) {
 463                 DBG_ERR("Unable to extract parent from dn\n");
 464                 TALLOC_FREE(frame);
 465                 return LDB_ERR_OPERATIONS_ERROR;
 466         }
 467
 468         query = build_wildcard_query(frame, dn);
 469         if (query == NULL) {
 470                 TALLOC_FREE(frame);
 471                 return LDB_ERR_OPERATIONS_ERROR;
 472         }
 473
 474         result = talloc_zero(mem_ctx, struct ldb_result);
 475         if (result == NULL) {
 476                 TALLOC_FREE(frame);
 477                 DBG_ERR("Unable to allocate ldb_result\n");
 478                 return LDB_ERR_OPERATIONS_ERROR;
 479         }
 480
 481         ret = ldb_build_search_req_ex(&request,
 482                                       samdb,
 483                                       frame,
 484                                       parent,
 485                                       LDB_SCOPE_ONELEVEL,
 486                                       query,
 487                                       attrs,
 488                                       NULL,
 489                                       result,
 490                                       ldb_search_default_callback,
 491                                       NULL);
 492         if (ret != LDB_SUCCESS) {
 493                 TALLOC_FREE(frame);
 494                 DBG_ERR("ldb_build_search_req_ex returned %d\n", ret);
 495                 return ret;
 496         }
 497
 498         ret = ldb_request(samdb, request);
 499         if (ret != LDB_SUCCESS) {
 500                 TALLOC_FREE(frame);
 501                 return ret;
 502         }
 503
 504         ret = ldb_wait(request->handle, LDB_WAIT_ALL);
 505         if (ret != LDB_SUCCESS) {
 506                 TALLOC_FREE(frame);
 507                 return ret;
 508         }
 509
 510         if (result->count == 0) {
 511                 TALLOC_FREE(frame);
 512                 return LDB_ERR_NO_SUCH_OBJECT;
 513         }
 514
 515         match = get_best_match(dn, result);
 516         if (match == NULL) {
 517                 TALLOC_FREE(frame);
 518                 return LDB_ERR_OPERATIONS_ERROR;
 519         }
 520
 521         *msg = talloc_move(mem_ctx, &match);
 522         TALLOC_FREE(frame);
 523         return LDB_SUCCESS;
 524 }
 525
 526 /*
 527  * Lookup a DNS record, will match DNS wild card records if an exact match
 528  * is not found.
 529  */
 530 WERROR dns_common_wildcard_lookup(struct ldb_context *samdb,
 531                                   TALLOC_CTX *mem_ctx,
 532                                   struct ldb_dn *dn,
 533                                   struct dnsp_DnssrvRpcRecord **records,
 534                                   uint16_t *num_records)
 535 {
 536         int ret;
 537         WERROR werr;
 538         struct ldb_message *msg = NULL;
 539         struct ldb_message_element *el = NULL;
 540         const struct ldb_val *name = NULL;
 541
 542         *records = NULL;
 543         *num_records = 0;
 544
 545         name = ldb_dn_get_rdn_val(dn);
 546         if (name == NULL) {
 547                 return DNS_ERR(NAME_ERROR);
 548         }
 549
 550         werr =  dns_name_check(
 551                         mem_ctx,
 552                         strlen((const char*)name->data),
 553                         (const char*) name->data);
 554         if (!W_ERROR_IS_OK(werr)) {
 555                 return werr;
 556         }
 557
 558         ret = dns_wildcard_lookup(samdb, mem_ctx, dn, &msg);
 559         if (ret == LDB_ERR_OPERATIONS_ERROR) {
 560                 return DNS_ERR(SERVER_FAILURE);
 561         }
 562         if (ret != LDB_SUCCESS) {
 563                 return DNS_ERR(NAME_ERROR);
 564         }
 565
 566         el = ldb_msg_find_element(msg, "dnsRecord");
 567         if (el == NULL) {
 568                 return WERR_DNS_ERROR_NAME_DOES_NOT_EXIST;
 569         }
 570
 571         werr = dns_common_extract(samdb, el, mem_ctx, records, num_records);
 572         TALLOC_FREE(msg);
 573         if (!W_ERROR_IS_OK(werr)) {
 574                 return werr;
 575         }
 576
 577         return WERR_OK;
 578 }
 579
 580 static int rec_cmp(const struct dnsp_DnssrvRpcRecord *r1,
 581                    const struct dnsp_DnssrvRpcRecord *r2)
 582 {
 583         if (r1->wType != r2->wType) {
 584                 /*
 585                  * The records are sorted with higher types first
 586                  */
 587                 return r2->wType - r1->wType;
 588         }
 589
 590         /*
 591          * Then we need to sort from the oldest to newest timestamp
 592          */
 593         return r1->dwTimeStamp - r2->dwTimeStamp;
 594 }
 595
 596 /*
 597  * Check for valid DNS names. These are names which:
 598  *   - are non-empty
 599  *   - do not start with a dot
 600  *   - do not have any empty labels
 601  *   - have no more than 127 labels
 602  *   - are no longer than 253 characters
 603  *   - none of the labels exceed 63 characters
 604  */
 605 WERROR dns_name_check(TALLOC_CTX *mem_ctx, size_t len, const char *name)
 606 {
 607         size_t i;
 608         unsigned int labels    = 0;
 609         unsigned int label_len = 0;
 610
 611         if (len == 0) {
 612                 return WERR_DS_INVALID_DN_SYNTAX;
 613         }
 614
 615         if (len > 1 && name[0] == '.') {
 616                 return WERR_DS_INVALID_DN_SYNTAX;
 617         }
 618
 619         if ((len - 1) > DNS_MAX_DOMAIN_LENGTH) {
 620                 return WERR_DS_INVALID_DN_SYNTAX;
 621         }
 622
 623         for (i = 0; i < len - 1; i++) {
 624                 if (name[i] == '.' && name[i+1] == '.') {
 625                         return WERR_DS_INVALID_DN_SYNTAX;
 626                 }
 627                 if (name[i] == '.') {
 628                         labels++;
 629                         if (labels > DNS_MAX_LABELS) {
 630                                 return WERR_DS_INVALID_DN_SYNTAX;
 631                         }
 632                         label_len = 0;
 633                 } else {
 634                         label_len++;
 635                         if (label_len > DNS_MAX_LABEL_LENGTH) {
 636                                 return WERR_DS_INVALID_DN_SYNTAX;
 637                         }
 638                 }
 639         }
 640
 641         return WERR_OK;
 642 }
 643
 644 static WERROR check_name_list(TALLOC_CTX *mem_ctx, uint16_t rec_count,
 645                               struct dnsp_DnssrvRpcRecord *records)
 646 {
 647         WERROR werr;
 648         uint16_t i;
 649         size_t len;
 650         struct dnsp_DnssrvRpcRecord record;
 651
 652         werr = WERR_OK;
 653         for (i = 0; i < rec_count; i++) {
 654                 record = records[i];
 655
 656                 switch (record.wType) {
 657
 658                 case DNS_TYPE_NS:
 659                         len = strlen(record.data.ns);
 660                         werr = dns_name_check(mem_ctx, len, record.data.ns);
 661                         break;
 662                 case DNS_TYPE_CNAME:
 663                         len = strlen(record.data.cname);
 664                         werr = dns_name_check(mem_ctx, len, record.data.cname);
 665                         break;
 666                 case DNS_TYPE_SOA:
 667                         len = strlen(record.data.soa.mname);
 668                         werr = dns_name_check(mem_ctx, len, record.data.soa.mname);
 669                         if (!W_ERROR_IS_OK(werr)) {
 670                                 break;
 671                         }
 672                         len = strlen(record.data.soa.rname);
 673                         werr = dns_name_check(mem_ctx, len, record.data.soa.rname);
 674                         break;
 675                 case DNS_TYPE_PTR:
 676                         len = strlen(record.data.ptr);
 677                         werr = dns_name_check(mem_ctx, len, record.data.ptr);
 678                         break;
 679                 case DNS_TYPE_MX:
 680                         len = strlen(record.data.mx.nameTarget);
 681                         werr = dns_name_check(mem_ctx, len, record.data.mx.nameTarget);
 682                         break;
 683                 case DNS_TYPE_SRV:
 684                         len = strlen(record.data.srv.nameTarget);
 685                         werr = dns_name_check(mem_ctx, len,
 686                                               record.data.srv.nameTarget);
 687                         break;
 688                 /*
 689                  * In the default case, the record doesn't have a DN, so it
 690                  * must be ok.
 691                  */
 692                 default:
 693                         break;
 694                 }
 695
 696                 if (!W_ERROR_IS_OK(werr)) {
 697                         return werr;
 698                 }
 699         }
 700
 701         return WERR_OK;
 702 }
 703
 704 WERROR dns_common_replace(struct ldb_context *samdb,
 705                           TALLOC_CTX *mem_ctx,
 706                           struct ldb_dn *dn,
 707                           bool needs_add,
 708                           uint32_t serial,
 709                           struct dnsp_DnssrvRpcRecord *records,
 710                           uint16_t rec_count)
 711 {
 712         struct ldb_message_element *el;
 713         uint16_t i;
 714         int ret;
 715         WERROR werr;
 716         struct ldb_message *msg = NULL;
 717         bool was_tombstoned = false;
 718         bool become_tombstoned = false;
 719
 720         msg = ldb_msg_new(mem_ctx);
 721         W_ERROR_HAVE_NO_MEMORY(msg);
 722
 723         msg->dn = dn;
 724
 725         werr = check_name_list(mem_ctx, rec_count, records);
 726         if (!W_ERROR_IS_OK(werr)) {
 727                 return werr;
 728         }
 729
 730         ret = ldb_msg_add_empty(msg, "dnsRecord", LDB_FLAG_MOD_REPLACE, &el);
 731         if (ret != LDB_SUCCESS) {
 732                 return DNS_ERR(SERVER_FAILURE);
 733         }
 734
 735         /*
 736          * we have at least one value,
 737          * which might be used for the tombstone marker
 738          */
 739         el->values = talloc_zero_array(el, struct ldb_val, MAX(1, rec_count));
 740         if (rec_count > 0) {
 741                 W_ERROR_HAVE_NO_MEMORY(el->values);
 742
 743                 /*
 744                  * We store a sorted list with the high wType values first
 745                  * that's what windows does. It also simplifies the
 746                  * filtering of DNS_TYPE_TOMBSTONE records
 747                  */
 748                 TYPESAFE_QSORT(records, rec_count, rec_cmp);
 749         }
 750
 751         for (i = 0; i < rec_count; i++) {
 752                 struct ldb_val *v = &el->values[el->num_values];
 753                 enum ndr_err_code ndr_err;
 754
 755                 if (records[i].wType == DNS_TYPE_TOMBSTONE) {
 756                         if (records[i].data.timestamp != 0) {
 757                                 was_tombstoned = true;
 758                         }
 759                         continue;
 760                 }
 761
 762                 records[i].dwSerial = serial;
 763                 ndr_err = ndr_push_struct_blob(v, el->values, &records[i],
 764                                 (ndr_push_flags_fn_t)ndr_push_dnsp_DnssrvRpcRecord);
 765                 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 766                         DEBUG(0, ("Failed to push dnsp_DnssrvRpcRecord\n"));
 767                         return DNS_ERR(SERVER_FAILURE);
 768                 }
 769                 el->num_values++;
 770         }
 771
 772         if (needs_add) {
 773                 if (el->num_values == 0) {
 774                         return WERR_OK;
 775                 }
 776
 777                 ret = ldb_msg_add_string(msg, "objectClass", "dnsNode");
 778                 if (ret != LDB_SUCCESS) {
 779                         return DNS_ERR(SERVER_FAILURE);
 780                 }
 781
 782                 ret = ldb_add(samdb, msg);
 783                 if (ret != LDB_SUCCESS) {
 784                         return DNS_ERR(SERVER_FAILURE);
 785                 }
 786
 787                 return WERR_OK;
 788         }
 789
 790         if (el->num_values == 0) {
 791                 struct dnsp_DnssrvRpcRecord tbs;
 792                 struct ldb_val *v = &el->values[el->num_values];
 793                 enum ndr_err_code ndr_err;
 794                 struct timeval tv;
 795
 796                 if (was_tombstoned) {
 797                         /*
 798                          * This is already a tombstoned object.
 799                          * Just leave it instead of updating the time stamp.
 800                          */
 801                         return WERR_OK;
 802                 }
 803
 804                 tv = timeval_current();
 805                 tbs = (struct dnsp_DnssrvRpcRecord) {
 806                         .wType = DNS_TYPE_TOMBSTONE,
 807                         .dwSerial = serial,
 808                         .data.timestamp = timeval_to_nttime(&tv),
 809                 };
 810
 811                 ndr_err = ndr_push_struct_blob(v, el->values, &tbs,
 812                                 (ndr_push_flags_fn_t)ndr_push_dnsp_DnssrvRpcRecord);
 813                 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 814                         DEBUG(0, ("Failed to push dnsp_DnssrvRpcRecord\n"));
 815                         return DNS_ERR(SERVER_FAILURE);
 816                 }
 817                 el->num_values++;
 818
 819                 become_tombstoned = true;
 820         }
 821
 822         if (was_tombstoned || become_tombstoned) {
 823                 ret = ldb_msg_add_empty(msg, "dNSTombstoned",
 824                                         LDB_FLAG_MOD_REPLACE, NULL);
 825                 if (ret != LDB_SUCCESS) {
 826                         return DNS_ERR(SERVER_FAILURE);
 827                 }
 828
 829                 ret = ldb_msg_add_fmt(msg, "dNSTombstoned", "%s",
 830                                       become_tombstoned ? "TRUE" : "FALSE");
 831                 if (ret != LDB_SUCCESS) {
 832                         return DNS_ERR(SERVER_FAILURE);
 833                 }
 834         }
 835
 836         ret = ldb_modify(samdb, msg);
 837         if (ret != LDB_SUCCESS) {
 838                 NTSTATUS nt = dsdb_ldb_err_to_ntstatus(ret);
 839                 return ntstatus_to_werror(nt);
 840         }
 841
 842         return WERR_OK;
 843 }
 844
 845 bool dns_name_match(const char *zone, const char *name, size_t *host_part_len)
 846 {
 847         size_t zl = strlen(zone);
 848         size_t nl = strlen(name);
 849         ssize_t zi, ni;
 850         static const size_t fixup = 'a' - 'A';
 851
 852         if (zl > nl) {
 853                 return false;
 854         }
 855
 856         for (zi = zl, ni = nl; zi >= 0; zi--, ni--) {
 857                 char zc = zone[zi];
 858                 char nc = name[ni];
 859
 860                 /* convert to lower case */
 861                 if (zc >= 'A' && zc <= 'Z') {
 862                         zc += fixup;
 863                 }
 864                 if (nc >= 'A' && nc <= 'Z') {
 865                         nc += fixup;
 866                 }
 867
 868                 if (zc != nc) {
 869                         return false;
 870                 }
 871         }
 872
 873         if (ni >= 0) {
 874                 if (name[ni] != '.') {
 875                         return false;
 876                 }
 877
 878                 ni--;
 879         }
 880
 881         *host_part_len = ni+1;
 882
 883         return true;
 884 }
 885
 886 WERROR dns_common_name2dn(struct ldb_context *samdb,
 887                           struct dns_server_zone *zones,
 888                           TALLOC_CTX *mem_ctx,
 889                           const char *name,
 890                           struct ldb_dn **_dn)
 891 {
 892         struct ldb_dn *base;
 893         struct ldb_dn *dn;
 894         const struct dns_server_zone *z;
 895         size_t host_part_len = 0;
 896         WERROR werr;
 897
 898         if (name == NULL) {
 899                 return DNS_ERR(FORMAT_ERROR);
 900         }
 901
 902         if (strcmp(name, "") == 0) {
 903                 base = ldb_get_default_basedn(samdb);
 904                 dn = ldb_dn_copy(mem_ctx, base);
 905                 ldb_dn_add_child_fmt(dn, "DC=@,DC=RootDNSServers,CN=MicrosoftDNS,CN=System");
 906                 *_dn = dn;
 907                 return WERR_OK;
 908         }
 909
 910         /* Check non-empty names */
 911         werr = dns_name_check(mem_ctx, strlen(name), name);
 912         if (!W_ERROR_IS_OK(werr)) {
 913                 return werr;
 914         }
 915
 916         for (z = zones; z != NULL; z = z->next) {
 917                 bool match;
 918
 919                 match = dns_name_match(z->name, name, &host_part_len);
 920                 if (match) {
 921                         break;
 922                 }
 923         }
 924
 925         if (z == NULL) {
 926                 return DNS_ERR(NAME_ERROR);
 927         }
 928
 929         if (host_part_len == 0) {
 930                 dn = ldb_dn_copy(mem_ctx, z->dn);
 931                 ldb_dn_add_child_fmt(dn, "DC=@");
 932                 *_dn = dn;
 933                 return WERR_OK;
 934         }
 935
 936         dn = ldb_dn_copy(mem_ctx, z->dn);
 937         ldb_dn_add_child_fmt(dn, "DC=%*.*s", (int)host_part_len, (int)host_part_len, name);
 938         *_dn = dn;
 939         return WERR_OK;
 940 }
 941
 942 static int dns_common_sort_zones(struct ldb_message **m1, struct ldb_message **m2)
 943 {
 944         const char *n1, *n2;
 945         size_t l1, l2;
 946
 947         n1 = ldb_msg_find_attr_as_string(*m1, "name", NULL);
 948         n2 = ldb_msg_find_attr_as_string(*m2, "name", NULL);
 949
 950         l1 = strlen(n1);
 951         l2 = strlen(n2);
 952
 953         /* If the string lengths are not equal just sort by length */
 954         if (l1 != l2) {
 955                 /* If m1 is the larger zone name, return it first */
 956                 return l2 - l1;
 957         }
 958
 959         /*TODO: We need to compare DNs here, we want the DomainDNSZones first */
 960         return 0;
 961 }
 962
 963 NTSTATUS dns_common_zones(struct ldb_context *samdb,
 964                           TALLOC_CTX *mem_ctx,
 965                           struct ldb_dn *base_dn,
 966                           struct dns_server_zone **zones_ret)
 967 {
 968         int ret;
 969         static const char * const attrs[] = { "name", NULL};
 970         struct ldb_result *res;
 971         int i;
 972         struct dns_server_zone *new_list = NULL;
 973         TALLOC_CTX *frame = talloc_stackframe();
 974
 975         if (base_dn) {
 976                 /* This search will work against windows */
 977                 ret = dsdb_search(samdb, frame, &res,
 978                                   base_dn, LDB_SCOPE_SUBTREE,
 979                                   attrs, 0, "(objectClass=dnsZone)");
 980         } else {
 981                 /* TODO: this search does not work against windows */
 982                 ret = dsdb_search(samdb, frame, &res, NULL,
 983                                   LDB_SCOPE_SUBTREE,
 984                                   attrs,
 985                                   DSDB_SEARCH_SEARCH_ALL_PARTITIONS,
 986                                   "(objectClass=dnsZone)");
 987         }
 988         if (ret != LDB_SUCCESS) {
 989                 TALLOC_FREE(frame);
 990                 return NT_STATUS_INTERNAL_DB_CORRUPTION;
 991         }
 992
 993         TYPESAFE_QSORT(res->msgs, res->count, dns_common_sort_zones);
 994
 995         for (i=0; i < res->count; i++) {
 996                 struct dns_server_zone *z;
 997
 998                 z = talloc_zero(mem_ctx, struct dns_server_zone);
 999                 if (z == NULL) {
1000                         TALLOC_FREE(frame);
1001                         return NT_STATUS_NO_MEMORY;
1002                 }
1003
1004                 z->name = ldb_msg_find_attr_as_string(res->msgs[i], "name", NULL);
1005                 talloc_steal(z, z->name);
1006                 z->dn = talloc_move(z, &res->msgs[i]->dn);
1007                 /*
1008                  * Ignore the RootDNSServers zone and zones that we don't support yet
1009                  * RootDNSServers should never be returned (Windows DNS server don't)
1010                  * ..TrustAnchors should never be returned as is, (Windows returns
1011                  * TrustAnchors) and for the moment we don't support DNSSEC so we'd better
1012                  * not return this zone.
1013                  */
1014                 if ((strcmp(z->name, "RootDNSServers") == 0) ||
1015                     (strcmp(z->name, "..TrustAnchors") == 0))
1016                 {
1017                         DEBUG(10, ("Ignoring zone %s\n", z->name));
1018                         talloc_free(z);
1019                         continue;
1020                 }
1021                 DLIST_ADD_END(new_list, z);
1022         }
1023
1024         *zones_ret = new_list;
1025         TALLOC_FREE(frame);
1026         return NT_STATUS_OK;
1027 }