source4/dns_server/dns_update.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    DNS server handler for update requests
   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 "librpc/ndr/libndr.h"
  25 #include "librpc/gen_ndr/ndr_dns.h"
  26 #include "librpc/gen_ndr/ndr_dnsp.h"
  27 #include <ldb.h>
  28 #include "dsdb/samdb/samdb.h"
  29 #include "dsdb/common/util.h"
  30 #include "dns_server/dns_server.h"
  31
  32 static WERROR check_prerequsites(struct dns_server *dns,
  33                                  TALLOC_CTX *mem_ctx,
  34                                  const struct dns_name_packet *in,
  35                                  const struct dns_res_rec *prereqs, uint16_t count)
  36 {
  37         const struct dns_name_question *zone;
  38         size_t host_part_len = 0;
  39         uint16_t i;
  40
  41         zone = in->questions;
  42
  43         for (i = 0; i < count; i++) {
  44                 const struct dns_res_rec *r = &prereqs[i];
  45                 bool match;
  46
  47                 if (r->ttl != 0) {
  48                         return DNS_ERR(FORMAT_ERROR);
  49                 }
  50                 match = dns_name_match(zone->name, r->name, &host_part_len);
  51                 if (!match) {
  52                         /* TODO: check if we need to echo all prereqs if the
  53                          * first fails */
  54                         return DNS_ERR(NOTZONE);
  55                 }
  56                 if (r->rr_class == DNS_QCLASS_ANY) {
  57                         if (r->length != 0) {
  58                                 return DNS_ERR(FORMAT_ERROR);
  59                         }
  60                         if (r->rr_type == DNS_QTYPE_ALL) {
  61                                 /* TODO: Check if zone has at least one RR */
  62                                 return DNS_ERR(NAME_ERROR);
  63                         } else {
  64                                 /* TODO: Check if RR exists of the specified type */
  65                                 return DNS_ERR(NXRRSET);
  66                         }
  67                 }
  68                 if (r->rr_class == DNS_QCLASS_NONE) {
  69                         if (r->length != 0) {
  70                                 return DNS_ERR(FORMAT_ERROR);
  71                         }
  72                         if (r->rr_type == DNS_QTYPE_ALL) {
  73                                 /* TODO: Return this error if the given name exits in this zone */
  74                                 return DNS_ERR(YXDOMAIN);
  75                         } else {
  76                                 /* TODO: Return error if there's an RRset of this type in the zone */
  77                                 return DNS_ERR(YXRRSET);
  78                         }
  79                 }
  80                 if (r->rr_class == zone->question_class) {
  81                         /* Check if there's a RR with this */
  82                         return DNS_ERR(NOT_IMPLEMENTED);
  83                 } else {
  84                         return DNS_ERR(FORMAT_ERROR);
  85                 }
  86         }
  87
  88
  89         return WERR_OK;
  90 }
  91
  92 static WERROR update_prescan(const struct dns_name_question *zone,
  93                              const struct dns_res_rec *updates, uint16_t count)
  94 {
  95         const struct dns_res_rec *r;
  96         uint16_t i;
  97         size_t host_part_len;
  98         bool match;
  99
 100         for (i = 0; i < count; i++) {
 101                 r = &updates[i];
 102                 match = dns_name_match(zone->name, r->name, &host_part_len);
 103                 if (!match) {
 104                         return DNS_ERR(NOTZONE);
 105                 }
 106                 if (zone->question_class == r->rr_class) {
 107                         /*TODO: also check for AXFR,MAILA,MAILB  */
 108                         if (r->rr_type == DNS_QTYPE_ALL) {
 109                                 return DNS_ERR(FORMAT_ERROR);
 110                         }
 111                 } else if (r->rr_class == DNS_QCLASS_ANY) {
 112                         if (r->ttl != 0 || r->length != 0) {
 113                                 return DNS_ERR(FORMAT_ERROR);
 114                         }
 115                 } else if (r->rr_class == DNS_QCLASS_NONE) {
 116                         if (r->ttl != 0 || r->rr_type == DNS_QTYPE_ALL) {
 117                                 return DNS_ERR(FORMAT_ERROR);
 118                         }
 119                 } else {
 120                         return DNS_ERR(FORMAT_ERROR);
 121                 }
 122         }
 123         return WERR_OK;
 124 }
 125
 126 WERROR dns_server_process_update(struct dns_server *dns,
 127                                  TALLOC_CTX *mem_ctx,
 128                                  struct dns_name_packet *in,
 129                                  const struct dns_res_rec *prereqs, uint16_t prereq_count,
 130                                  struct dns_res_rec **updates,      uint16_t *update_count,
 131                                  struct dns_res_rec **additional,   uint16_t *arcount)
 132 {
 133         struct dns_name_question *zone;
 134         const struct dns_server_zone *z;
 135         size_t host_part_len = 0;
 136         WERROR werror = DNS_ERR(NOT_IMPLEMENTED);
 137         bool update_allowed = false;
 138
 139         if (in->qdcount != 1) {
 140                 return DNS_ERR(FORMAT_ERROR);
 141         }
 142
 143         zone = in->questions;
 144
 145         if (zone->question_type != DNS_QTYPE_SOA) {
 146                 return DNS_ERR(FORMAT_ERROR);
 147         }
 148
 149         DEBUG(0, ("Got a dns update request.\n"));
 150
 151         for (z = dns->zones; z != NULL; z = z->next) {
 152                 bool match;
 153
 154                 match = dns_name_match(z->name, zone->name, &host_part_len);
 155                 if (match) {
 156                         break;
 157                 }
 158         }
 159
 160         if (z == NULL) {
 161                 return DNS_ERR(NOTAUTH);
 162         }
 163
 164         if (host_part_len != 0) {
 165                 /* TODO: We need to delegate this one */
 166                 return DNS_ERR(NOT_IMPLEMENTED);
 167         }
 168
 169         werror = check_prerequsites(dns, mem_ctx, in, prereqs, prereq_count);
 170         W_ERROR_NOT_OK_RETURN(werror);
 171
 172         /* TODO: Check if update is allowed, we probably want "always",
 173          * key-based GSSAPI, key-based bind-style TSIG and "never" as
 174          * smb.conf options. */
 175         if (!update_allowed) {
 176                 return DNS_ERR(REFUSED);
 177         }
 178
 179         werror = update_prescan(in->questions, *updates, *update_count);
 180         W_ERROR_NOT_OK_RETURN(werror);
 181
 182         return werror;
 183 }