freebsd-dev/usr.sbin/pkg/dns_utils.c
Baptiste Daroussin 8ad6d9175c Fix a bad calloc(3) call
MFC after:	2 weeks
2013-06-08 23:48:13 +00:00

136 lines
3.4 KiB
C

/*-
* Copyright (c) 2012 Baptiste Daroussin <bapt@FreeBSD.org>
* 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,
* without modification, immediately at the beginning of the file.
* 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.
*
* 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <stdlib.h>
#include <string.h>
#include <netinet/in.h>
#include <resolv.h>
#include "dns_utils.h"
typedef union {
HEADER hdr;
unsigned char buf[1024];
} dns_query;
struct dns_srvinfo *
dns_getsrvinfo(const char *zone)
{
struct dns_srvinfo **res, *first;
unsigned char *end, *p;
char host[MAXHOSTNAMELEN];
dns_query q;
int len, qdcount, ancount, n, i;
unsigned int type, class, ttl, priority, weight, port;
if ((len = res_query(zone, C_IN, T_SRV, q.buf, sizeof(q.buf))) == -1 ||
len < (int)sizeof(HEADER))
return (NULL);
qdcount = ntohs(q.hdr.qdcount);
ancount = ntohs(q.hdr.ancount);
end = q.buf + len;
p = q.buf + sizeof(HEADER);
while(qdcount > 0 && p < end) {
qdcount--;
if((len = dn_expand(q.buf, end, p, host, MAXHOSTNAMELEN)) < 0)
return (NULL);
p += len + NS_QFIXEDSZ;
}
res = calloc(ancount, sizeof(struct dns_srvinfo *));
if (res == NULL)
return (NULL);
n = 0;
while (ancount > 0 && p < end) {
ancount--;
len = dn_expand(q.buf, end, p, host, MAXHOSTNAMELEN);
if (len < 0) {
for (i = 0; i < n; i++)
free(res[i]);
free(res);
return NULL;
}
p += len;
NS_GET16(type, p);
NS_GET16(class, p);
NS_GET32(ttl, p);
NS_GET16(len, p);
if (type != T_SRV) {
p += len;
continue;
}
NS_GET16(priority, p);
NS_GET16(weight, p);
NS_GET16(port, p);
len = dn_expand(q.buf, end, p, host, MAXHOSTNAMELEN);
if (len < 0) {
for (i = 0; i < n; i++)
free(res[i]);
free(res);
return (NULL);
}
res[n] = malloc(sizeof(struct dns_srvinfo));
if (res[n] == NULL) {
for (i = 0; i < n; i++)
free(res[i]);
free(res);
return (NULL);
}
res[n]->type = type;
res[n]->class = class;
res[n]->ttl = ttl;
res[n]->priority = priority;
res[n]->weight = weight;
res[n]->port = port;
res[n]->next = NULL;
strlcpy(res[n]->host, host, MAXHOSTNAMELEN);
p += len;
n++;
}
for (i = 0; i < n - 1; i++)
res[i]->next = res[i + 1];
first = res[0];
free(res);
return (first);
}