dnssec.c revision 1.3
1/* $OpenBSD: dnssec.c,v 1.3 2001/01/27 15:39:54 ho Exp $ */ 2 3/* 4 * Copyright (c) 2001 H�kan Olsson. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. The name of the author may not be used to endorse or promote products 15 * derived from this software without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29#include <sys/types.h> 30#include <netinet/in.h> 31#include <arpa/nameser.h> 32#include <arpa/inet.h> 33#include <stdlib.h> 34 35#include <openssl/rsa.h> 36#include <dns/keyvalues.h> 37#include <lwres/lwres.h> 38#include <lwres/netdb.h> 39 40#include "sysdep.h" 41 42#include "dnssec.h" 43#include "exchange.h" 44#include "ipsec_num.h" 45#include "libcrypto.h" 46#include "log.h" 47#include "message.h" 48#include "transport.h" 49 50/* adapted from <dns/rdatastruct.h> / RFC 2535 */ 51struct dns_rdata_key { 52 u_int16_t flags; 53 u_int8_t protocol; 54 u_int8_t algorithm; 55 u_int16_t datalen; 56 unsigned char *data; 57}; 58 59/* XXX IPv4 specific */ 60void * 61dns_get_key (int type, struct message *msg, int *keylen) 62{ 63 struct rrsetinfo *rr; 64 struct hostent *hostent; 65 struct sockaddr_in *dst; 66 int ret, i; 67 struct dns_rdata_key key_rr; 68 u_int8_t algorithm; 69 70 switch (type) 71 { 72 case IKE_AUTH_RSA_SIG: 73 algorithm = DNS_KEYALG_RSA; 74 break; 75 76 case IKE_AUTH_RSA_ENC: 77 case IKE_AUTH_RSA_ENC_REV: 78 /* XXX Not yet. */ 79 /* algorithm = DNS_KEYALG_RSA; */ 80 return 0; 81 82 case IKE_AUTH_DSS: 83 /* XXX Not yet. */ 84 /* algorithm = DNS_KEYALG_DSS; */ 85 return 0; 86 87 case IKE_AUTH_PRE_SHARED: 88 default: 89 return 0; 90 } 91 92 /* Get peer IP address */ 93 msg->transport->vtbl->get_dst (msg->transport, (struct sockaddr **)&dst, &i); 94 /* Get peer name and aliases */ 95 hostent = lwres_gethostbyaddr ((char *)&dst->sin_addr, 96 sizeof (struct in_addr), PF_INET); 97 98 if (!hostent) 99 { 100 LOG_DBG ((LOG_MISC, 30, 101 "dns_get_key: lwres_gethostbyaddr (%s) failed: %s", 102 inet_ntoa (((struct sockaddr_in *)dst)->sin_addr), 103 lwres_hstrerror (lwres_h_errno))); 104 return 0; 105 } 106 107 /* Try host official name */ 108 LOG_DBG ((LOG_MISC, 50, "dns_get_key: trying KEY RR for %s", 109 hostent->h_name)); 110 ret = lwres_getrrsetbyname (hostent->h_name, C_IN, T_KEY, 0, &rr); 111 if (ret) 112 { 113 /* Try host aliases */ 114 i = 0; 115 while (hostent->h_aliases[i] && ret) 116 { 117 LOG_DBG ((LOG_MISC, 50, "dns_get_key: trying KEY RR for alias %s", 118 hostent->h_aliases[i])); 119 ret = lwres_getrrsetbyname (hostent->h_aliases[i], C_IN, T_KEY, 0, 120 &rr); 121 i++; 122 } 123 } 124 125 if (ret) 126 { 127 LOG_DBG ((LOG_MISC, 30, "dns_get_key: no DNS responses (error %d)", 128 ret)); 129 return 0; 130 } 131 132 LOG_DBG ((LOG_MISC, 80, 133 "dns_get_key: rrset class %d type %d ttl %d nrdatas %d nrsigs %d", 134 rr->rri_rdclass, rr->rri_rdtype, rr->rri_ttl, rr->rri_nrdatas, 135 rr->rri_nsigs)); 136 137 /* We don't accept unvalidated data. */ 138 if (!(rr->rri_flags & RRSET_VALIDATED)) 139 { 140 LOG_DBG ((LOG_MISC, 10, "dns_get_key: got unvalidated response")); 141 lwres_freerrset (rr); 142 return 0; 143 } 144 145 /* Sanity. */ 146 if (rr->rri_nrdatas == 0 || rr->rri_rdtype != T_KEY) 147 { 148 LOG_DBG ((LOG_MISC, 30, "dns_get_key: no KEY RRs recieved")); 149 lwres_freerrset (rr); 150 return 0; 151 } 152 153 memset (&key_rr, 0, sizeof key_rr); 154 155 /* 156 * Find a key with the wanted algorithm, if any. 157 * XXX If there are several keys present, we currently only find the first. 158 */ 159 for (i = 0; i < rr->rri_nrdatas && key_rr.datalen == 0; i++) 160 { 161 key_rr.flags = ntohs ((u_int16_t) *rr->rri_rdatas[i].rdi_data); 162 key_rr.protocol = *(rr->rri_rdatas[i].rdi_data + 2); 163 key_rr.algorithm = *(rr->rri_rdatas[i].rdi_data + 3); 164 165 if (key_rr.protocol != DNS_KEYPROTO_IPSEC) 166 { 167 LOG_DBG ((LOG_MISC, 50, "dns_get_key: ignored non-IPSEC key")); 168 continue; 169 } 170 171 if (key_rr.algorithm != algorithm) 172 { 173 LOG_DBG ((LOG_MISC, 50, "dns_get_key: ignored key with other alg")); 174 continue; 175 } 176 177 key_rr.datalen = rr->rri_rdatas[i].rdi_length - 4; 178 if (key_rr.datalen <= 0) 179 { 180 LOG_DBG ((LOG_MISC, 50, "dns_get_key: ignored bad key")); 181 key_rr.datalen = 0; 182 continue; 183 } 184 185 /* This key seems to fit our requirements... */ 186 key_rr.data = (char *)malloc (key_rr.datalen); 187 if (!key_rr.data) 188 { 189 log_error ("dns_get_key: malloc (%d) failed", key_rr.datalen); 190 lwres_freerrset (rr); 191 return 0; 192 } 193 memcpy (key_rr.data, rr->rri_rdatas[i].rdi_data + 4, key_rr.datalen); 194 *keylen = key_rr.datalen; 195 } 196 197 lwres_freerrset (rr); 198 199 if (key_rr.datalen) 200 return key_rr.data; 201 else 202 return 0; 203} 204 205int 206dns_RSA_dns_to_x509 (u_int8_t *key, int keylen, RSA **rsa_key) 207{ 208 RSA *rsa; 209 int key_offset; 210 u_int8_t e_len; 211 212 if (!key || keylen <= 0) 213 { 214 log_print ("dns_RSA_dns_to_x509: invalid public key"); 215 return -1; 216 } 217 218 rsa = LC (RSA_new, ()); 219 if (rsa == NULL) 220 { 221 log_error ("dns_RSA_dns_to_x509: failed to allocate new RSA struct"); 222 return -1; 223 } 224 225 e_len = *key; 226 key_offset = 1; 227 228 if (e_len == 0) 229 { 230 if (keylen < 3) 231 { 232 log_print ("dns_RSA_dns_to_x509: invalid public key"); 233 LC (RSA_free, (rsa)); 234 return -1; 235 } 236 e_len = *(key + key_offset++) << 8; 237 e_len += *(key + key_offset++); 238 } 239 240 if (e_len > (keylen - key_offset)) 241 { 242 log_print ("dns_RSA_dns_to_x509: invalid public key"); 243 LC (RSA_free, (rsa)); 244 return -1; 245 } 246 247 rsa->e = LC (BN_bin2bn, (key + key_offset, e_len, NULL)); 248 key_offset += e_len; 249 250 /* XXX if (keylen <= key_offset) -> "invalid public key" ? */ 251 252 rsa->n = LC (BN_bin2bn, (key + key_offset, keylen - key_offset, NULL)); 253 254 *rsa_key = rsa; 255 256 LOG_DBG ((LOG_MISC, 30, "dns_RSA_dns_to_x509: got %d bits RSA key", 257 LC (BN_num_bits, (rsa->n)))); 258 259 return 0; 260} 261 262#if notyet 263int 264dns_RSA_x509_to_dns (RSA *rsa_key, u_int8_t *key, int *keylen) 265{ 266 return 0; 267} 268#endif 269