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/* $OpenBSD: dnssec.c,v 1.2 2001/01/27 12:03:32 niklas Exp $ */
/*
* Copyright (c) 2001 Håkan Olsson. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <stdlib.h>
#include <string.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <arpa/inet.h>
#include <dns/keyvalues.h>
#include <lwres/lwres.h>
#include <lwres/netdb.h>
#include <openssl/rsa.h>
#include "sysdep.h"
#include "exchange.h"
#include "log.h"
#include "message.h"
#include "transport.h"
#include "ipsec_num.h"
#include "dnssec.h"
/* adapted from <dns/rdatastruct.h> / RFC 2535 */
struct dns_rdata_key {
u_int16_t flags;
u_int8_t protocol;
u_int8_t algorithm;
u_int16_t datalen;
unsigned char *data;
};
/* XXX IPv4 specific */
void *
dns_get_key (int type, struct message *msg, int *keylen)
{
struct rrsetinfo *rr;
struct hostent *hostent;
struct sockaddr_in *dst;
int ret, i;
struct dns_rdata_key key_rr;
u_int8_t algorithm;
switch (type)
{
case IKE_AUTH_RSA_SIG:
algorithm = DNS_KEYALG_RSA;
break;
case IKE_AUTH_RSA_ENC:
case IKE_AUTH_RSA_ENC_REV:
/* XXX Not yes. */
/* algorithm = DNS_KEYALG_RSA; */
return NULL;
case IKE_AUTH_DSS:
/* XXX Not yet. */
/* algorithm = DNS_KEYALG_DSS; */
return NULL;
case IKE_AUTH_PRE_SHARED:
default:
return NULL;
}
/* Get peer IP address */
msg->transport->vtbl->get_dst (msg->transport, (struct sockaddr **)&dst, &i);
/* Get peer name and aliases */
hostent = lwres_gethostbyaddr ((char *)&dst->sin_addr,
sizeof (struct in_addr), PF_INET);
if (!hostent)
{
LOG_DBG ((LOG_MISC, 30,
"dns_get_key: lwres_gethostbyaddr (%s) failed: %s",
inet_ntoa (((struct sockaddr_in *)dst)->sin_addr),
lwres_hstrerror (lwres_h_errno)));
return NULL;
}
/* Try host official name */
LOG_DBG ((LOG_MISC, 50, "dns_get_key: trying KEY RR for %s",
hostent->h_name));
ret = lwres_getrrsetbyname (hostent->h_name, C_IN, T_KEY, 0, &rr);
if (ret)
{
/* Try host aliases */
i = 0;
while (hostent->h_aliases[i] && ret)
{
LOG_DBG ((LOG_MISC, 50, "dns_get_key: trying KEY RR for alias %s",
hostent->h_aliases[i]));
ret = lwres_getrrsetbyname (hostent->h_aliases[i], C_IN, T_KEY, 0,
&rr);
i ++;
}
}
if (ret)
{
LOG_DBG ((LOG_MISC, 30, "dns_get_key: no DNS responses (error %d)",
ret));
return NULL;
}
LOG_DBG ((LOG_MISC, 80,
"dns_get_key: rrset class %d type %d ttl %d nrdatas %d nrsigs %d",
rr->rri_rdclass, rr->rri_rdtype, rr->rri_ttl, rr->rri_nrdatas,
rr->rri_nsigs));
/* We don't accept unvalidated data. */
if (!(rr->rri_flags & RRSET_VALIDATED))
{
LOG_DBG ((LOG_MISC, 10, "dns_get_key: got unvalidated response"));
lwres_freerrset (rr);
return NULL;
}
/* Sanity. */
if (rr->rri_nrdatas == 0 || rr->rri_rdtype != T_KEY)
{
LOG_DBG ((LOG_MISC, 30, "dns_get_key: no KEY RRs recieved"));
lwres_freerrset (rr);
return NULL;
}
memset (&key_rr, 0, sizeof (key_rr));
/*
* Find a key with the wanted algorithm, if any.
* XXX If there are several keys present, we currently only find the first.
*/
for (i = 0; i < rr->rri_nrdatas && key_rr.datalen == 0; i ++)
{
key_rr.flags = ntohs ((u_int16_t) *rr->rri_rdatas[i].rdi_data);
key_rr.protocol = *(rr->rri_rdatas[i].rdi_data + 2);
key_rr.algorithm = *(rr->rri_rdatas[i].rdi_data + 3);
if (key_rr.protocol != DNS_KEYPROTO_IPSEC)
{
LOG_DBG ((LOG_MISC, 50, "dns_get_key: ignored non-IPSEC key"));
continue;
}
if (key_rr.algorithm != algorithm)
{
LOG_DBG ((LOG_MISC, 50, "dns_get_key: ignored key with other alg"));
continue;
}
key_rr.datalen = rr->rri_rdatas[i].rdi_length - 4;
if (key_rr.datalen <= 0)
{
LOG_DBG ((LOG_MISC, 50, "dns_get_key: ignored bad key"));
key_rr.datalen = 0;
continue;
}
/* This key seems to fit our requirements... */
key_rr.data = (char *)malloc (key_rr.datalen);
if (!key_rr.data)
{
log_error ("dns_get_key: malloc (%d) failed", key_rr.datalen);
lwres_freerrset (rr);
return NULL;
}
memcpy (key_rr.data, rr->rri_rdatas[i].rdi_data + 4, key_rr.datalen);
*keylen = key_rr.datalen;
}
lwres_freerrset (rr);
if (key_rr.datalen)
return key_rr.data;
else
return NULL;
}
int
dns_RSA_dns_to_x509 (u_int8_t *key, int keylen, RSA **rsa_key)
{
RSA *rsa;
int key_offset;
u_int8_t e_len;
if (!key || keylen <= 0)
{
log_print ("dns_RSA_dns_to_x509: invalid public key");
return -1;
}
rsa = RSA_new ();
if (!rsa)
{
log_error ("dns_RSA_dns_to_x509: failed to allocate new RSA struct");
return -1;
}
e_len = *key;
key_offset = 1;
if (e_len == 0)
{
if (keylen < 3)
{
log_print ("dns_RSA_dns_to_x509: invalid public key");
RSA_free (rsa);
return -1;
}
e_len = *(key + key_offset++) << 8;
e_len += *(key + key_offset++);
}
if (e_len > (keylen - key_offset))
{
log_print ("dns_RSA_dns_to_x509: invalid public key");
RSA_free (rsa);
return -1;
}
rsa->e = BN_bin2bn (key + key_offset, e_len, NULL);
key_offset += e_len;
/* XXX if (keylen <= key_offset) -> "invalid public key" ? */
rsa->n = BN_bin2bn (key + key_offset, keylen - key_offset, NULL);
*rsa_key = rsa;
LOG_DBG ((LOG_MISC, 30, "dns_RSA_dns_to_x509: got %d bits RSA key",
BN_num_bits (rsa->n)));
return 0;
}
#if notyet
int
dns_RSA_x509_to_dns (RSA *rsa_key, u_int8_t *key, int *keylen)
{
return 0;
}
#endif
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