1 /* 2 * util/edns.c - handle base EDNS options. 3 * 4 * Copyright (c) 2018, 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 for base EDNS options. 40 */ 41 42 #include "config.h" 43 #include "util/edns.h" 44 #include "util/config_file.h" 45 #include "util/netevent.h" 46 #include "util/net_help.h" 47 #include "util/regional.h" 48 #include "util/rfc_1982.h" 49 #include "util/siphash.h" 50 #include "util/data/msgparse.h" 51 #include "util/data/msgreply.h" 52 #include "sldns/sbuffer.h" 53 54 #if 0 55 /* XXX: remove me */ 56 #include "edns.h" 57 #endif 58 59 struct edns_strings* edns_strings_create(void) 60 { 61 struct edns_strings* edns_strings = calloc(1, 62 sizeof(struct edns_strings)); 63 if(!edns_strings) 64 return NULL; 65 if(!(edns_strings->region = regional_create())) { 66 edns_strings_delete(edns_strings); 67 return NULL; 68 } 69 return edns_strings; 70 } 71 72 void edns_strings_delete(struct edns_strings* edns_strings) 73 { 74 if(!edns_strings) 75 return; 76 regional_destroy(edns_strings->region); 77 free(edns_strings); 78 } 79 80 static int 81 edns_strings_client_insert(struct edns_strings* edns_strings, 82 struct sockaddr_storage* addr, socklen_t addrlen, int net, 83 const char* string) 84 { 85 struct edns_string_addr* esa = regional_alloc_zero(edns_strings->region, 86 sizeof(struct edns_string_addr)); 87 if(!esa) 88 return 0; 89 esa->string_len = strlen(string); 90 esa->string = regional_alloc_init(edns_strings->region, string, 91 esa->string_len); 92 if(!esa->string) 93 return 0; 94 if(!addr_tree_insert(&edns_strings->client_strings, &esa->node, addr, 95 addrlen, net)) { 96 verbose(VERB_QUERY, "duplicate EDNS client string ignored."); 97 } 98 return 1; 99 } 100 101 int edns_strings_apply_cfg(struct edns_strings* edns_strings, 102 struct config_file* config) 103 { 104 struct config_str2list* c; 105 regional_free_all(edns_strings->region); 106 addr_tree_init(&edns_strings->client_strings); 107 108 for(c=config->edns_client_strings; c; c=c->next) { 109 struct sockaddr_storage addr; 110 socklen_t addrlen; 111 int net; 112 log_assert(c->str && c->str2); 113 114 if(!netblockstrtoaddr(c->str, UNBOUND_DNS_PORT, &addr, &addrlen, 115 &net)) { 116 log_err("cannot parse EDNS client string IP netblock: " 117 "%s", c->str); 118 return 0; 119 } 120 if(!edns_strings_client_insert(edns_strings, &addr, addrlen, 121 net, c->str2)) { 122 log_err("out of memory while adding EDNS strings"); 123 return 0; 124 } 125 } 126 edns_strings->client_string_opcode = config->edns_client_string_opcode; 127 128 addr_tree_init_parents(&edns_strings->client_strings); 129 return 1; 130 } 131 132 struct edns_string_addr* 133 edns_string_addr_lookup(rbtree_type* tree, struct sockaddr_storage* addr, 134 socklen_t addrlen) 135 { 136 return (struct edns_string_addr*)addr_tree_lookup(tree, addr, addrlen); 137 } 138 139 uint8_t* 140 edns_cookie_server_hash(const uint8_t* in, const uint8_t* secret, int v4, 141 uint8_t* hash) 142 { 143 v4?siphash(in, 20, secret, hash, 8):siphash(in, 32, secret, hash, 8); 144 return hash; 145 } 146 147 void 148 edns_cookie_server_write(uint8_t* buf, const uint8_t* secret, int v4, 149 uint32_t timestamp) 150 { 151 uint8_t hash[8]; 152 buf[ 8] = 1; /* Version */ 153 buf[ 9] = 0; /* Reserved */ 154 buf[10] = 0; /* Reserved */ 155 buf[11] = 0; /* Reserved */ 156 sldns_write_uint32(buf + 12, timestamp); 157 (void)edns_cookie_server_hash(buf, secret, v4, hash); 158 memcpy(buf + 16, hash, 8); 159 } 160 161 enum edns_cookie_val_status 162 edns_cookie_server_validate(const uint8_t* cookie, size_t cookie_len, 163 const uint8_t* secret, size_t secret_len, int v4, 164 const uint8_t* hash_input, uint32_t now) 165 { 166 uint8_t hash[8]; 167 uint32_t timestamp; 168 uint32_t subt_1982 = 0; /* Initialize for the compiler; unused value */ 169 int comp_1982; 170 if(cookie_len != 24) 171 /* RFC9018 cookies are 24 bytes long */ 172 return COOKIE_STATUS_CLIENT_ONLY; 173 if(secret_len != 16 || /* RFC9018 cookies have 16 byte secrets */ 174 cookie[8] != 1) /* RFC9018 cookies are cookie version 1 */ 175 return COOKIE_STATUS_INVALID; 176 timestamp = sldns_read_uint32(cookie + 12); 177 if((comp_1982 = compare_1982(now, timestamp)) > 0 178 && (subt_1982 = subtract_1982(timestamp, now)) > 3600) 179 /* Cookie is older than 1 hour (see RFC9018 Section 4.3.) */ 180 return COOKIE_STATUS_EXPIRED; 181 if(comp_1982 <= 0 && subtract_1982(now, timestamp) > 300) 182 /* Cookie time is more than 5 minutes in the future. 183 * (see RFC9018 Section 4.3.) */ 184 return COOKIE_STATUS_FUTURE; 185 if(memcmp(edns_cookie_server_hash(hash_input, secret, v4, hash), 186 cookie + 16, 8) != 0) 187 /* Hashes do not match */ 188 return COOKIE_STATUS_INVALID; 189 if(comp_1982 > 0 && subt_1982 > 1800) 190 /* Valid cookie but older than 30 minutes, so create a new one 191 * anyway */ 192 return COOKIE_STATUS_VALID_RENEW; 193 return COOKIE_STATUS_VALID; 194 } 195