/*
* Copyright (c) 2000-2004, 2010 Proofpoint, Inc. and its suppliers.
* All rights reserved.
*
* By using this file, you agree to the terms and conditions set
* forth in the LICENSE file which can be found at the top level of
* the sendmail distribution.
*
*/
/*
* Copyright (c) 1995, 1996, 1997, 1998, 1999 Kungliga Tekniska H�gskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* 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. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``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 INSTITUTE OR CONTRIBUTORS 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 <sendmail.h>
#if DNSMAP
# if NAMED_BIND
# if NETINET
# include <netinet/in_systm.h>
# include <netinet/ip.h>
# endif /* NETINET */
# include "sm_resolve.h"
SM_RCSID("$Id: sm_resolve.c,v 8.40 2013-11-22 20:51:56 ca Exp $")
static struct stot
{
const char *st_name;
int st_type;
} stot[] =
{
# if NETINET
{ "A", T_A },
# endif /* NETINET */
# if NETINET6
{ "AAAA", T_AAAA },
# endif /* NETINET6 */
{ "NS", T_NS },
{ "CNAME", T_CNAME },
{ "PTR", T_PTR },
{ "MX", T_MX },
{ "TXT", T_TXT },
{ "AFSDB", T_AFSDB },
{ "SRV", T_SRV },
{ NULL, 0 }
};
static DNS_REPLY_T *parse_dns_reply __P((unsigned char *, int));
/*
** DNS_STRING_TO_TYPE -- convert resource record name into type
**
** Parameters:
** name -- name of resource record type
**
** Returns:
** type if succeeded.
** -1 otherwise.
*/
int
dns_string_to_type(name)
const char *name;
{
struct stot *p = stot;
for (p = stot; p->st_name != NULL; p++)
if (sm_strcasecmp(name, p->st_name) == 0)
return p->st_type;
return -1;
}
/*
** DNS_TYPE_TO_STRING -- convert resource record type into name
**
** Parameters:
** type -- resource record type
**
** Returns:
** name if succeeded.
** NULL otherwise.
*/
const char *
dns_type_to_string(type)
int type;
{
struct stot *p = stot;
for (p = stot; p->st_name != NULL; p++)
if (type == p->st_type)
return p->st_name;
return NULL;
}
/*
** DNS_FREE_DATA -- free all components of a DNS_REPLY_T
**
** Parameters:
** r -- pointer to DNS_REPLY_T
**
** Returns:
** none.
*/
void
dns_free_data(r)
DNS_REPLY_T *r;
{
RESOURCE_RECORD_T *rr;
if (r->dns_r_q.dns_q_domain != NULL)
sm_free(r->dns_r_q.dns_q_domain);
for (rr = r->dns_r_head; rr != NULL; )
{
RESOURCE_RECORD_T *tmp = rr;
if (rr->rr_domain != NULL)
sm_free(rr->rr_domain);
if (rr->rr_u.rr_data != NULL)
sm_free(rr->rr_u.rr_data);
rr = rr->rr_next;
sm_free(tmp);
}
sm_free(r);
}
/*
** PARSE_DNS_REPLY -- parse DNS reply data.
**
** Parameters:
** data -- pointer to dns data
** len -- len of data
**
** Returns:
** pointer to DNS_REPLY_T if succeeded.
** NULL otherwise.
*/
static DNS_REPLY_T *
parse_dns_reply(data, len)
unsigned char *data;
int len;
{
unsigned char *p;
unsigned short ans_cnt, ui;
int status;
size_t l;
char host[MAXHOSTNAMELEN];
DNS_REPLY_T *r;
RESOURCE_RECORD_T **rr;
r = (DNS_REPLY_T *) sm_malloc(sizeof(*r));
if (r == NULL)
return NULL;
memset(r, 0, sizeof(*r));
p = data;
/* doesn't work on Crays? */
memcpy(&r->dns_r_h, p, sizeof(r->dns_r_h));
p += sizeof(r->dns_r_h);
status = dn_expand(data, data + len, p, host, sizeof(host));
if (status < 0)
{
dns_free_data(r);
return NULL;
}
r->dns_r_q.dns_q_domain = sm_strdup(host);
if (r->dns_r_q.dns_q_domain == NULL)
{
dns_free_data(r);
return NULL;
}
ans_cnt = ntohs((unsigned short) r->dns_r_h.ancount);
p += status;
GETSHORT(r->dns_r_q.dns_q_type, p);
GETSHORT(r->dns_r_q.dns_q_class, p);
rr = &r->dns_r_head;
ui = 0;
while (p < data + len && ui < ans_cnt)
{
int type, class, ttl, size, txtlen;
status = dn_expand(data, data + len, p, host, sizeof(host));
if (status < 0)
{
dns_free_data(r);
return NULL;
}
++ui;
p += status;
GETSHORT(type, p);
GETSHORT(class, p);
GETLONG(ttl, p);
GETSHORT(size, p);
if (p + size > data + len)
{
/*
** announced size of data exceeds length of
** data paket: someone is cheating.
*/
if (LogLevel > 5)
sm_syslog(LOG_WARNING, NOQID,
"ERROR: DNS RDLENGTH=%d > data len=%d",
size, len - (p - data));
dns_free_data(r);
return NULL;
}
*rr = (RESOURCE_RECORD_T *) sm_malloc(sizeof(**rr));
if (*rr == NULL)
{
dns_free_data(r);
return NULL;
}
memset(*rr, 0, sizeof(**rr));
(*rr)->rr_domain = sm_strdup(host);
if ((*rr)->rr_domain == NULL)
{
dns_free_data(r);
return NULL;
}
(*rr)->rr_type = type;
(*rr)->rr_class = class;
(*rr)->rr_ttl = ttl;
(*rr)->rr_size = size;
switch (type)
{
case T_NS:
case T_CNAME:
case T_PTR:
status = dn_expand(data, data + len, p, host,
sizeof(host));
if (status < 0)
{
dns_free_data(r);
return NULL;
}
(*rr)->rr_u.rr_txt = sm_strdup(host);
if ((*rr)->rr_u.rr_txt == NULL)
{
dns_free_data(r);
return NULL;
}
break;
case T_MX:
case T_AFSDB:
status = dn_expand(data, data + len, p + 2, host,
sizeof(host));
if (status < 0)
{
dns_free_data(r);
return NULL;
}
l = strlen(host) + 1;
(*rr)->rr_u.rr_mx = (MX_RECORD_T *)
sm_malloc(sizeof(*((*rr)->rr_u.rr_mx)) + l);
if ((*rr)->rr_u.rr_mx == NULL)
{
dns_free_data(r);
return NULL;
}
(*rr)->rr_u.rr_mx->mx_r_preference = (p[0] << 8) | p[1];
(void) sm_strlcpy((*rr)->rr_u.rr_mx->mx_r_domain,
host, l);
break;
case T_SRV:
status = dn_expand(data, data + len, p + 6, host,
sizeof(host));
if (status < 0)
{
dns_free_data(r);
return NULL;
}
l = strlen(host) + 1;
(*rr)->rr_u.rr_srv = (SRV_RECORDT_T*)
sm_malloc(sizeof(*((*rr)->rr_u.rr_srv)) + l);
if ((*rr)->rr_u.rr_srv == NULL)
{
dns_free_data(r);
return NULL;
}
(*rr)->rr_u.rr_srv->srv_r_priority = (p[0] << 8) | p[1];
(*rr)->rr_u.rr_srv->srv_r_weight = (p[2] << 8) | p[3];
(*rr)->rr_u.rr_srv->srv_r_port = (p[4] << 8) | p[5];
(void) sm_strlcpy((*rr)->rr_u.rr_srv->srv_r_target,
host, l);
break;
case T_TXT:
/*
** The TXT record contains the length as
** leading byte, hence the value is restricted
** to 255, which is less than the maximum value
** of RDLENGTH (size). Nevertheless, txtlen
** must be less than size because the latter
** specifies the length of the entire TXT
** record.
*/
txtlen = *p;
if (txtlen >= size)
{
if (LogLevel > 5)
sm_syslog(LOG_WARNING, NOQID,
"ERROR: DNS TXT record size=%d <= text len=%d",
size, txtlen);
dns_free_data(r);
return NULL;
}
(*rr)->rr_u.rr_txt = (char *) sm_malloc(txtlen + 1);
if ((*rr)->rr_u.rr_txt == NULL)
{
dns_free_data(r);
return NULL;
}
(void) sm_strlcpy((*rr)->rr_u.rr_txt, (char*) p + 1,
txtlen + 1);
break;
default:
(*rr)->rr_u.rr_data = (unsigned char*) sm_malloc(size);
if ((*rr)->rr_u.rr_data == NULL)
{
dns_free_data(r);
return NULL;
}
(void) memcpy((*rr)->rr_u.rr_data, p, size);
break;
}
p += size;
rr = &(*rr)->rr_next;
}
*rr = NULL;
return r;
}
/*
** DNS_LOOKUP_INT -- perform dns map lookup (internal helper routine)
**
** Parameters:
** domain -- name to lookup
** rr_class -- resource record class
** rr_type -- resource record type
** retrans -- retransmission timeout
** retry -- number of retries
**
** Returns:
** result of lookup if succeeded.
** NULL otherwise.
*/
DNS_REPLY_T *
dns_lookup_int(domain, rr_class, rr_type, retrans, retry)
const char *domain;
int rr_class;
int rr_type;
time_t retrans;
int retry;
{
int len;
unsigned long old_options = 0;
time_t save_retrans = 0;
int save_retry = 0;
DNS_REPLY_T *r = NULL;
querybuf reply_buf;
unsigned char *reply;
#define SMRBSIZE sizeof(reply_buf)
#ifndef IP_MAXPACKET
# define IP_MAXPACKET 65535
#endif
if (tTd(8, 16))
{
old_options = _res.options;
_res.options |= RES_DEBUG;
sm_dprintf("dns_lookup(%s, %d, %s)\n", domain,
rr_class, dns_type_to_string(rr_type));
}
if (retrans > 0)
{
save_retrans = _res.retrans;
_res.retrans = retrans;
}
if (retry > 0)
{
save_retry = _res.retry;
_res.retry = retry;
}
errno = 0;
SM_SET_H_ERRNO(0);
reply = (unsigned char *)&reply_buf;
len = res_search(domain, rr_class, rr_type, reply, SMRBSIZE);
if (len >= SMRBSIZE)
{
if (len >= IP_MAXPACKET)
{
if (tTd(8, 4))
sm_dprintf("dns_lookup: domain=%s, length=%d, default_size=%d, max=%d, status=response too long\n",
domain, len, (int) SMRBSIZE,
IP_MAXPACKET);
}
else
{
if (tTd(8, 6))
sm_dprintf("dns_lookup: domain=%s, length=%d, default_size=%d, max=%d, status=response longer than default size, resizing\n",
domain, len, (int) SMRBSIZE,
IP_MAXPACKET);
reply = (unsigned char *)sm_malloc(IP_MAXPACKET);
if (reply == NULL)
SM_SET_H_ERRNO(TRY_AGAIN);
else
len = res_search(domain, rr_class, rr_type,
reply, IP_MAXPACKET);
}
}
if (tTd(8, 16))
{
_res.options = old_options;
sm_dprintf("dns_lookup(%s, %d, %s) --> %d\n",
domain, rr_class, dns_type_to_string(rr_type), len);
}
if (len >= 0 && len < IP_MAXPACKET && reply != NULL)
r = parse_dns_reply(reply, len);
if (reply != (unsigned char *)&reply_buf && reply != NULL)
{
sm_free(reply);
reply = NULL;
}
if (retrans > 0)
_res.retrans = save_retrans;
if (retry > 0)
_res.retry = save_retry;
return r;
}
# if 0
DNS_REPLY_T *
dns_lookup(domain, type_name, retrans, retry)
const char *domain;
const char *type_name;
time_t retrans;
int retry;
{
int type;
type = dns_string_to_type(type_name);
if (type == -1)
{
if (tTd(8, 16))
sm_dprintf("dns_lookup: unknown resource type: `%s'\n",
type_name);
return NULL;
}
return dns_lookup_int(domain, C_IN, type, retrans, retry);
}
# endif /* 0 */
# endif /* NAMED_BIND */
#endif /* DNSMAP */