unbound/iterator/iter_priv.c

   1 /*
   2  * iterator/iter_priv.c - iterative resolver private address and domain store
   3  *
   4  * Copyright (c) 2008, NLnet Labs. All rights reserved.
   5  *
   6  * This software is open source.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * Redistributions of source code must retain the above copyright notice,
  13  * this list of conditions and the following disclaimer.
  14  *
  15  * Redistributions in binary form must reproduce the above copyright notice,
  16  * this list of conditions and the following disclaimer in the documentation
  17  * and/or other materials provided with the distribution.
  18  *
  19  * Neither the name of the NLNET LABS nor the names of its contributors may
  20  * be used to endorse or promote products derived from this software without
  21  * specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  24  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  25  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  26  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  27  * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  28  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
  29  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  30  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  31  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  32  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  33  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  34  */
  35
  36 /**
  37  * \file
  38  *
  39  * This file contains functions to assist the iterator module.
  40  * Keep track of the private addresses and lookup fast.
  41  */
  42
  43 #include "config.h"
  44 #include "iterator/iter_priv.h"
  45 #include "util/regional.h"
  46 #include "util/log.h"
  47 #include "util/config_file.h"
  48 #include "util/data/dname.h"
  49 #include "util/data/msgparse.h"
  50 #include "util/net_help.h"
  51 #include "util/storage/dnstree.h"
  52 #include "ldns/str2wire.h"
  53 #include "ldns/sbuffer.h"
  54
  55 struct iter_priv* priv_create(void)
  56 {
  57         struct iter_priv* priv = (struct iter_priv*)calloc(1, sizeof(*priv));
  58         if(!priv)
  59                 return NULL;
  60         priv->region = regional_create();
  61         if(!priv->region) {
  62                 priv_delete(priv);
  63                 return NULL;
  64         }
  65         addr_tree_init(&priv->a);
  66         name_tree_init(&priv->n);
  67         return priv;
  68 }
  69
  70 void priv_delete(struct iter_priv* priv)
  71 {
  72         if(!priv) return;
  73         regional_destroy(priv->region);
  74         free(priv);
  75 }
  76
  77 /** Read private-addr declarations from config */
  78 static int read_addrs(struct iter_priv* priv, struct config_file* cfg)
  79 {
  80         /* parse addresses, report errors, insert into tree */
  81         struct config_strlist* p;
  82         struct addr_tree_node* n;
  83         struct sockaddr_storage addr;
  84         int net;
  85         socklen_t addrlen;
  86
  87         for(p = cfg->private_address; p; p = p->next) {
  88                 log_assert(p->str);
  89                 if(!netblockstrtoaddr(p->str, UNBOUND_DNS_PORT, &addr,
  90                         &addrlen, &net)) {
  91                         log_err("cannot parse private-address: %s", p->str);
  92                         return 0;
  93                 }
  94                 n = (struct addr_tree_node*)regional_alloc(priv->region,
  95                         sizeof(*n));
  96                 if(!n) {
  97                         log_err("out of memory");
  98                         return 0;
  99                 }
 100                 if(!addr_tree_insert(&priv->a, n, &addr, addrlen, net)) {
 101                         verbose(VERB_QUERY, "ignoring duplicate "
 102                                 "private-address: %s", p->str);
 103                 }
 104         }
 105         return 1;
 106 }
 107
 108 /** Read private-domain declarations from config */
 109 static int read_names(struct iter_priv* priv, struct config_file* cfg)
 110 {
 111         /* parse names, report errors, insert into tree */
 112         struct config_strlist* p;
 113         struct name_tree_node* n;
 114         uint8_t* nm, *nmr;
 115         size_t nm_len;
 116         int nm_labs;
 117
 118         for(p = cfg->private_domain; p; p = p->next) {
 119                 log_assert(p->str);
 120                 nm = sldns_str2wire_dname(p->str, &nm_len);
 121                 if(!nm) {
 122                         log_err("cannot parse private-domain: %s", p->str);
 123                         return 0;
 124                 }
 125                 nm_labs = dname_count_size_labels(nm, &nm_len);
 126                 nmr = (uint8_t*)regional_alloc_init(priv->region, nm, nm_len);
 127                 free(nm);
 128                 if(!nmr) {
 129                         log_err("out of memory");
 130                         return 0;
 131                 }
 132                 n = (struct name_tree_node*)regional_alloc(priv->region,
 133                         sizeof(*n));
 134                 if(!n) {
 135                         log_err("out of memory");
 136                         return 0;
 137                 }
 138                 if(!name_tree_insert(&priv->n, n, nmr, nm_len, nm_labs,
 139                         LDNS_RR_CLASS_IN)) {
 140                         verbose(VERB_QUERY, "ignoring duplicate "
 141                                 "private-domain: %s", p->str);
 142                 }
 143         }
 144         return 1;
 145 }
 146
 147 int priv_apply_cfg(struct iter_priv* priv, struct config_file* cfg)
 148 {
 149         /* empty the current contents */
 150         regional_free_all(priv->region);
 151         addr_tree_init(&priv->a);
 152         name_tree_init(&priv->n);
 153
 154         /* read new contents */
 155         if(!read_addrs(priv, cfg))
 156                 return 0;
 157         if(!read_names(priv, cfg))
 158                 return 0;
 159
 160         /* prepare for lookups */
 161         addr_tree_init_parents(&priv->a);
 162         name_tree_init_parents(&priv->n);
 163         return 1;
 164 }
 165
 166 /**
 167  * See if an address is blocked.
 168  * @param priv: structure for address storage.
 169  * @param addr: address to check
 170  * @param addrlen: length of addr.
 171  * @return: true if the address must not be queried. false if unlisted.
 172  */
 173 static int
 174 priv_lookup_addr(struct iter_priv* priv, struct sockaddr_storage* addr,
 175         socklen_t addrlen)
 176 {
 177         return addr_tree_lookup(&priv->a, addr, addrlen) != NULL;
 178 }
 179
 180 /**
 181  * See if a name is whitelisted.
 182  * @param priv: structure for address storage.
 183  * @param pkt: the packet (for compression ptrs).
 184  * @param name: name to check.
 185  * @param name_len: uncompressed length of the name to check.
 186  * @param dclass: class to check.
 187  * @return: true if the name is OK. false if unlisted.
 188  */
 189 static int
 190 priv_lookup_name(struct iter_priv* priv, sldns_buffer* pkt,
 191         uint8_t* name, size_t name_len, uint16_t dclass)
 192 {
 193         size_t len;
 194         uint8_t decomp[256];
 195         int labs;
 196         if(name_len >= sizeof(decomp))
 197                 return 0;
 198         dname_pkt_copy(pkt, decomp, name);
 199         labs = dname_count_size_labels(decomp, &len);
 200         log_assert(name_len == len);
 201         return name_tree_lookup(&priv->n, decomp, len, labs, dclass) != NULL;
 202 }
 203
 204 size_t priv_get_mem(struct iter_priv* priv)
 205 {
 206         if(!priv) return 0;
 207         return sizeof(*priv) + regional_get_mem(priv->region);
 208 }
 209
 210 /** remove RR from msgparse RRset, return true if rrset is entirely bad */
 211 static int
 212 remove_rr(const char* str, sldns_buffer* pkt, struct rrset_parse* rrset,
 213         struct rr_parse* prev, struct rr_parse** rr, struct sockaddr_storage* addr, socklen_t addrlen)
 214 {
 215         if(verbosity >= VERB_QUERY && rrset->dname_len <= LDNS_MAX_DOMAINLEN && str) {
 216                 uint8_t buf[LDNS_MAX_DOMAINLEN+1];
 217                 dname_pkt_copy(pkt, buf, rrset->dname);
 218                 log_name_addr(VERB_QUERY, str, buf, addr, addrlen);
 219         }
 220         if(prev)
 221                 prev->next = (*rr)->next;
 222         else    rrset->rr_first = (*rr)->next;
 223         if(rrset->rr_last == *rr)
 224                 rrset->rr_last = prev;
 225         rrset->rr_count --;
 226         rrset->size -= (*rr)->size;
 227         /* rr struct still exists, but is unlinked, so that in the for loop
 228          * the rr->next works fine to continue. */
 229         return rrset->rr_count == 0;
 230 }
 231
 232 int priv_rrset_bad(struct iter_priv* priv, sldns_buffer* pkt,
 233         struct rrset_parse* rrset)
 234 {
 235         if(priv->a.count == 0)
 236                 return 0; /* there are no blocked addresses */
 237
 238         /* see if it is a private name, that is allowed to have any */
 239         if(priv_lookup_name(priv, pkt, rrset->dname, rrset->dname_len,
 240                 ntohs(rrset->rrset_class))) {
 241                 return 0;
 242         } else {
 243                 /* so its a public name, check the address */
 244                 socklen_t len;
 245                 struct rr_parse* rr, *prev = NULL;
 246                 if(rrset->type == LDNS_RR_TYPE_A) {
 247                         struct sockaddr_storage addr;
 248                         struct sockaddr_in sa;
 249
 250                         len = (socklen_t)sizeof(sa);
 251                         memset(&sa, 0, len);
 252                         sa.sin_family = AF_INET;
 253                         sa.sin_port = (in_port_t)htons(UNBOUND_DNS_PORT);
 254                         for(rr = rrset->rr_first; rr; rr = rr->next) {
 255                                 if(sldns_read_uint16(rr->ttl_data+4)
 256                                         != INET_SIZE) {
 257                                         prev = rr;
 258                                         continue;
 259                                 }
 260                                 memmove(&sa.sin_addr, rr->ttl_data+4+2,
 261                                         INET_SIZE);
 262                                 memmove(&addr, &sa, len);
 263                                 if(priv_lookup_addr(priv, &addr, len)) {
 264                                         if(remove_rr("sanitize: removing public name with private address", pkt, rrset, prev, &rr, &addr, len))
 265                                                 return 1;
 266                                         continue;
 267                                 }
 268                                 prev = rr;
 269                         }
 270                 } else if(rrset->type == LDNS_RR_TYPE_AAAA) {
 271                         struct sockaddr_storage addr;
 272                         struct sockaddr_in6 sa;
 273                         len = (socklen_t)sizeof(sa);
 274                         memset(&sa, 0, len);
 275                         sa.sin6_family = AF_INET6;
 276                         sa.sin6_port = (in_port_t)htons(UNBOUND_DNS_PORT);
 277                         for(rr = rrset->rr_first; rr; rr = rr->next) {
 278                                 if(sldns_read_uint16(rr->ttl_data+4)
 279                                         != INET6_SIZE) {
 280                                         prev = rr;
 281                                         continue;
 282                                 }
 283                                 memmove(&sa.sin6_addr, rr->ttl_data+4+2,
 284                                         INET6_SIZE);
 285                                 memmove(&addr, &sa, len);
 286                                 if(priv_lookup_addr(priv, &addr, len)) {
 287                                         if(remove_rr("sanitize: removing public name with private address", pkt, rrset, prev, &rr, &addr, len))
 288                                                 return 1;
 289                                         continue;
 290                                 }
 291                                 prev = rr;
 292                         }
 293                 }
 294         }
 295         return 0;
 296 }