Aren
/
NetBSD
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
NetBSD/dist/bind/lib/irs/dns_ho.c

1155 lines
27 KiB
C
Raw Blame History

/* $NetBSD: dns_ho.c,v 1.7 2003/08/07 09:21:02 agc Exp $ */
/*
* Copyright (c) 1985, 1988, 1993
* The Regents of the University of California. 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 University 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 REGENTS 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 REGENTS 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.
*/
/*
* Portions Copyright (c) 1996-1999 by Internet Software Consortium.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
* CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
* SOFTWARE.
*/
/* from gethostnamadr.c 8.1 (Berkeley) 6/4/93 */
/* BIND Id: gethnamaddr.c,v 8.15 1996/05/22 04:56:30 vixie Exp $ */
#if defined(LIBC_SCCS) && !defined(lint)
static const char rcsid[] = "Id: dns_ho.c,v 1.42.6.1 2003/06/02 09:24:40 marka Exp";
#endif /* LIBC_SCCS and not lint */
/* Imports. */
#include "port_before.h"
#include <sys/types.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>
#include <ctype.h>
#include <errno.h>
#include <stdlib.h>
#include <netdb.h>
#include <resolv.h>
#include <stdio.h>
#include <string.h>
#include <syslog.h>
#include <isc/memcluster.h>
#include <irs.h>
#include "port_after.h"
#include "irs_p.h"
#include "dns_p.h"
#ifdef SPRINTF_CHAR
# define SPRINTF(x) strlen(sprintf/**/x)
#else
# define SPRINTF(x) sprintf x
#endif
/* Definitions. */
#define MAXALIASES 35
#define MAXADDRS 35
#define MAXPACKET (65535) /* Maximum TCP message size */
#define BOUNDS_CHECK(ptr, count) \
if ((ptr) + (count) > eom) { \
had_error++; \
continue; \
} else (void)0
typedef union {
HEADER hdr;
u_char buf[MAXPACKET];
} querybuf;
struct dns_res_target {
struct dns_res_target *next;
querybuf qbuf; /* query buffer */
u_char *answer; /* buffer to put answer */
int anslen; /* size of answer buffer */
int qclass, qtype; /* class and type of query */
int action; /* condition whether query is really issued */
char qname[MAXDNAME +1]; /* domain name */
#if 0
int n; /* result length */
#endif
};
enum {RESTGT_DOALWAYS, RESTGT_AFTERFAILURE, RESTGT_IGNORE};
enum {RESQRY_SUCCESS, RESQRY_FAIL};
struct pvt {
struct hostent host;
char * h_addr_ptrs[MAXADDRS + 1];
char * host_aliases[MAXALIASES];
char hostbuf[8*1024];
u_char host_addr[16]; /* IPv4 or IPv6 */
struct __res_state *res;
void (*free_res)(void *);
};
typedef union {
int32_t al;
char ac;
} align;
static const u_char mapped[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0xff,0xff };
static const u_char tunnelled[] = { 0,0, 0,0, 0,0, 0,0, 0,0, 0,0 };
/* Note: the IPv6 loopback address is in the "tunnel" space */
static const u_char v6local[] = { 0,0, 0,1 }; /* last 4 bytes of IPv6 addr */
/* Forwards. */
static void ho_close(struct irs_ho *this);
static struct hostent * ho_byname(struct irs_ho *this, const char *name);
static struct hostent * ho_byname2(struct irs_ho *this, const char *name,
int af);
static struct hostent * ho_byaddr(struct irs_ho *this, const void *addr,
int len, int af);
static struct hostent * ho_next(struct irs_ho *this);
static void ho_rewind(struct irs_ho *this);
static void ho_minimize(struct irs_ho *this);
static struct __res_state * ho_res_get(struct irs_ho *this);
static void ho_res_set(struct irs_ho *this,
struct __res_state *res,
void (*free_res)(void *));
static struct addrinfo * ho_addrinfo(struct irs_ho *this, const char *name,
const struct addrinfo *pai);
static void map_v4v6_hostent(struct hostent *hp, char **bp,
char *ep);
static void addrsort(res_state, char **, int);
static struct hostent * gethostans(struct irs_ho *this,
const u_char *ansbuf, int anslen,
const char *qname, int qtype,
int af, int size,
struct addrinfo **ret_aip,
const struct addrinfo *pai);
static int add_hostent(struct pvt *pvt, char *bp, char **hap,
struct addrinfo *ai);
static int init(struct irs_ho *this);
/* Exports. */
struct irs_ho *
irs_dns_ho(struct irs_acc *this) {
struct irs_ho *ho;
struct pvt *pvt;
UNUSED(this);
if (!(pvt = memget(sizeof *pvt))) {
errno = ENOMEM;
return (NULL);
}
memset(pvt, 0, sizeof *pvt);
if (!(ho = memget(sizeof *ho))) {
memput(pvt, sizeof *pvt);
errno = ENOMEM;
return (NULL);
}
memset(ho, 0x5e, sizeof *ho);
ho->private = pvt;
ho->close = ho_close;
ho->byname = ho_byname;
ho->byname2 = ho_byname2;
ho->byaddr = ho_byaddr;
ho->next = ho_next;
ho->rewind = ho_rewind;
ho->minimize = ho_minimize;
ho->res_get = ho_res_get;
ho->res_set = ho_res_set;
ho->addrinfo = ho_addrinfo;
return (ho);
}
/* Methods. */
static void
ho_close(struct irs_ho *this) {
struct pvt *pvt = (struct pvt *)this->private;
ho_minimize(this);
if (pvt->res && pvt->free_res)
(*pvt->free_res)(pvt->res);
if (pvt)
memput(pvt, sizeof *pvt);
memput(this, sizeof *this);
}
static struct hostent *
ho_byname(struct irs_ho *this, const char *name) {
struct pvt *pvt = (struct pvt *)this->private;
struct hostent *hp;
if (init(this) == -1)
return (NULL);
if (pvt->res->options & RES_USE_INET6) {
hp = ho_byname2(this, name, AF_INET6);
if (hp)
return (hp);
}
return (ho_byname2(this, name, AF_INET));
}
static struct hostent *
ho_byname2(struct irs_ho *this, const char *name, int af)
{
struct pvt *pvt = (struct pvt *)this->private;
struct hostent *hp = NULL;
int n, size;
char tmp[NS_MAXDNAME];
const char *cp;
struct addrinfo ai;
struct dns_res_target *q, *p;
int querystate = RESQRY_FAIL;
if (init(this) == -1)
return (NULL);
q = memget(sizeof(*q));
if (q == NULL) {
RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL);
errno = ENOMEM;
goto cleanup;
}
memset(q, 0, sizeof(q));
switch (af) {
case AF_INET:
size = INADDRSZ;
q->qclass = C_IN;
q->qtype = T_A;
q->answer = q->qbuf.buf;
q->anslen = sizeof(q->qbuf);
q->action = RESTGT_DOALWAYS;
break;
case AF_INET6:
size = IN6ADDRSZ;
q->qclass = C_IN;
q->qtype = T_AAAA;
q->answer = q->qbuf.buf;
q->anslen = sizeof(q->qbuf);
q->action = RESTGT_DOALWAYS;
break;
default:
RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL);
errno = EAFNOSUPPORT;
hp = NULL;
goto cleanup;
}
/*
* if there aren't any dots, it could be a user-level alias.
* this is also done in res_nquery() since we are not the only
* function that looks up host names.
*/
if (!strchr(name, '.') && (cp = res_hostalias(pvt->res, name,
tmp, sizeof tmp)))
name = cp;
for (p = q; p; p = p->next) {
switch(p->action) {
case RESTGT_DOALWAYS:
break;
case RESTGT_AFTERFAILURE:
if (querystate == RESQRY_SUCCESS)
continue;
break;
case RESTGT_IGNORE:
continue;
}
if ((n = res_nsearch(pvt->res, name, p->qclass, p->qtype,
p->answer, p->anslen)) < 0) {
querystate = RESQRY_FAIL;
continue;
}
memset(&ai, 0, sizeof(ai));
ai.ai_family = af;
if ((hp = gethostans(this, p->answer, n, name, p->qtype,
af, size, NULL,
(const struct addrinfo *)&ai)) != NULL)
goto cleanup; /* no more loop is necessary */
querystate = RESQRY_FAIL;
continue;
}
cleanup:
if (q != NULL)
memput(q, sizeof(*q));
return(hp);
}
static struct hostent *
ho_byaddr(struct irs_ho *this, const void *addr, int len, int af)
{
struct pvt *pvt = (struct pvt *)this->private;
const u_char *uaddr = addr;
char *qp;
struct hostent *hp = NULL;
struct addrinfo ai;
struct dns_res_target *q, *q2, *p;
int n, size, i;
int querystate = RESQRY_FAIL;
if (init(this) == -1)
return (NULL);
q = memget(sizeof(*q));
q2 = memget(sizeof(*q2));
if (q == NULL || q2 == NULL) {
RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL);
errno = ENOMEM;
goto cleanup;
}
memset(q, 0, sizeof(q));
memset(q2, 0, sizeof(q2));
if (af == AF_INET6 && len == IN6ADDRSZ &&
(!memcmp(uaddr, mapped, sizeof mapped) ||
(!memcmp(uaddr, tunnelled, sizeof tunnelled) &&
memcmp(&uaddr[sizeof tunnelled], v6local, sizeof(v6local))))) {
/* Unmap. */
addr = (const char *)addr + sizeof mapped;
uaddr += sizeof mapped;
af = AF_INET;
len = INADDRSZ;
}
switch (af) {
case AF_INET:
size = INADDRSZ;
q->qclass = C_IN;
q->qtype = T_PTR;
q->answer = q->qbuf.buf;
q->anslen = sizeof(q->qbuf);
q->action = RESTGT_DOALWAYS;
break;
case AF_INET6:
size = IN6ADDRSZ;
q->qclass = C_IN;
q->qtype = T_PTR;
q->answer = q->qbuf.buf;
q->anslen = sizeof(q->qbuf);
q->next = q2;
q->action = RESTGT_DOALWAYS;
q2->qclass = C_IN;
q2->qtype = T_PTR;
q2->answer = q2->qbuf.buf;
q2->anslen = sizeof(q2->qbuf);
if ((pvt->res->options & RES_NO_NIBBLE2) != 0)
q2->action = RESTGT_IGNORE;
else
q2->action = RESTGT_AFTERFAILURE;
break;
default:
errno = EAFNOSUPPORT;
RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL);
hp = NULL;
goto cleanup;
}
if (size > len) {
errno = EINVAL;
RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL);
hp = NULL;
goto cleanup;
}
switch (af) {
case AF_INET:
qp = q->qname;
(void) sprintf(qp, "%u.%u.%u.%u.in-addr.arpa",
(uaddr[3] & 0xff),
(uaddr[2] & 0xff),
(uaddr[1] & 0xff),
(uaddr[0] & 0xff));
break;
case AF_INET6:
if (q->action != RESTGT_IGNORE) {
qp = q->qname;
for (n = IN6ADDRSZ - 1; n >= 0; n--) {
i = SPRINTF((qp, "%x.%x.",
uaddr[n] & 0xf,
(uaddr[n] >> 4) & 0xf));
if (i < 0)
abort();
qp += i;
}
#ifdef HAVE_STRLCAT
strlcat(q->qname, res_get_nibblesuffix(pvt->res),
sizeof(q->qname));
#else
strcpy(qp, res_get_nibblesuffix(pvt->res));
#endif
}
if (q2->action != RESTGT_IGNORE) {
qp = q2->qname;
for (n = IN6ADDRSZ - 1; n >= 0; n--) {
i = SPRINTF((qp, "%x.%x.",
uaddr[n] & 0xf,
(uaddr[n] >> 4) & 0xf));
if (i < 0)
abort();
qp += i;
}
#ifdef HAVE_STRLCAT
strlcat(q->qname, res_get_nibblesuffix2(pvt->res),
sizeof(q->qname));
#else
strcpy(qp, res_get_nibblesuffix2(pvt->res));
#endif
}
break;
default:
abort();
}
for (p = q; p; p = p->next) {
switch(p->action) {
case RESTGT_DOALWAYS:
break;
case RESTGT_AFTERFAILURE:
if (querystate == RESQRY_SUCCESS)
continue;
break;
case RESTGT_IGNORE:
continue;
}
if ((n = res_nquery(pvt->res, p->qname, p->qclass, p->qtype,
p->answer, p->anslen)) < 0) {
querystate = RESQRY_FAIL;
continue;
}
memset(&ai, 0, sizeof(ai));
ai.ai_family = af;
hp = gethostans(this, p->answer, n, p->qname, T_PTR, af, size,
NULL, (const struct addrinfo *)&ai);
if (!hp) {
querystate = RESQRY_FAIL;
continue;
}
memcpy(pvt->host_addr, addr, len);
pvt->h_addr_ptrs[0] = (char *)pvt->host_addr;
pvt->h_addr_ptrs[1] = NULL;
if (af == AF_INET && (pvt->res->options & RES_USE_INET6)) {
map_v4v6_address((char*)pvt->host_addr,
(char*)pvt->host_addr);
pvt->host.h_addrtype = AF_INET6;
pvt->host.h_length = IN6ADDRSZ;
}
RES_SET_H_ERRNO(pvt->res, NETDB_SUCCESS);
goto cleanup; /* no more loop is necessary. */
}
hp = NULL; /* H_ERRNO was set by subroutines */
cleanup:
if (q != NULL)
memput(q, sizeof(*q));
if (q2 != NULL)
memput(q2, sizeof(*q2));
return(hp);
}
static struct hostent *
ho_next(struct irs_ho *this) {
UNUSED(this);
return (NULL);
}
static void
ho_rewind(struct irs_ho *this) {
UNUSED(this);
/* NOOP */
}
static void
ho_minimize(struct irs_ho *this) {
struct pvt *pvt = (struct pvt *)this->private;
if (pvt->res)
res_nclose(pvt->res);
}
static struct __res_state *
ho_res_get(struct irs_ho *this) {
struct pvt *pvt = (struct pvt *)this->private;
if (!pvt->res) {
struct __res_state *res;
res = (struct __res_state *)malloc(sizeof *res);
if (!res) {
errno = ENOMEM;
return (NULL);
}
memset(res, 0, sizeof *res);
ho_res_set(this, res, free);
}
return (pvt->res);
}
/* XXX */
extern struct addrinfo *addr2addrinfo __P((const struct addrinfo *,
const char *));
static struct addrinfo *
ho_addrinfo(struct irs_ho *this, const char *name, const struct addrinfo *pai)
{
struct pvt *pvt = (struct pvt *)this->private;
int n;
char tmp[NS_MAXDNAME];
const char *cp;
struct dns_res_target *q, *q2, *p;
struct addrinfo sentinel, *cur;
int querystate = RESQRY_FAIL;
if (init(this) == -1)
return (NULL);
memset(&sentinel, 0, sizeof(sentinel));
cur = &sentinel;
q = memget(sizeof(*q));
q2 = memget(sizeof(*q2));
if (q == NULL || q2 == NULL) {
RES_SET_H_ERRNO(pvt->res, NETDB_INTERNAL);
errno = ENOMEM;
goto cleanup;
}
memset(q, 0, sizeof(q2));
memset(q2, 0, sizeof(q2));
switch (pai->ai_family) {
case AF_UNSPEC:
/* prefer IPv6 */
q->qclass = C_IN;
q->qtype = T_AAAA;
q->answer = q->qbuf.buf;
q->anslen = sizeof(q->qbuf);
q->next = q2;
q->action = RESTGT_DOALWAYS;
q2->qclass = C_IN;
q2->qtype = T_A;
q2->answer = q2->qbuf.buf;
q2->anslen = sizeof(q2->qbuf);
q2->action = RESTGT_DOALWAYS;
break;
case AF_INET:
q->qclass = C_IN;
q->qtype = T_A;
q->answer = q->qbuf.buf;
q->anslen = sizeof(q->qbuf);
q->action = RESTGT_DOALWAYS;
break;
case AF_INET6:
q->qclass = C_IN;
q->qtype = T_AAAA;
q->answer = q->qbuf.buf;
q->anslen = sizeof(q->qbuf);
q->action = RESTGT_DOALWAYS;
break;
default:
RES_SET_H_ERRNO(pvt->res, NO_RECOVERY); /* better error? */
goto cleanup;
}
/*
* if there aren't any dots, it could be a user-level alias.
* this is also done in res_nquery() since we are not the only
* function that looks up host names.
*/
if (!strchr(name, '.') && (cp = res_hostalias(pvt->res, name,
tmp, sizeof tmp)))
name = cp;
for (p = q; p; p = p->next) {
struct addrinfo *ai;
switch(p->action) {
case RESTGT_DOALWAYS:
break;
case RESTGT_AFTERFAILURE:
if (querystate == RESQRY_SUCCESS)
continue;
break;
case RESTGT_IGNORE:
continue;
}
if ((n = res_nsearch(pvt->res, name, p->qclass, p->qtype,
p->answer, p->anslen)) < 0) {
querystate = RESQRY_FAIL;
continue;
}
(void)gethostans(this, p->answer, n, name, p->qtype,
pai->ai_family, /* XXX: meaningless */
0, &ai, pai);
if (ai) {
querystate = RESQRY_SUCCESS;
cur->ai_next = ai;
while (cur && cur->ai_next)
cur = cur->ai_next;
}
else
querystate = RESQRY_FAIL;
}
cleanup:
if (q != NULL)
memput(q, sizeof(*q));
if (q2 != NULL)
memput(q2, sizeof(*q2));
return(sentinel.ai_next);
}
static void
ho_res_set(struct irs_ho *this, struct __res_state *res,
void (*free_res)(void *)) {
struct pvt *pvt = (struct pvt *)this->private;
if (pvt->res && pvt->free_res) {
res_nclose(pvt->res);
(*pvt->free_res)(pvt->res);
}
pvt->res = res;
pvt->free_res = free_res;
}
/* Private. */
static struct hostent *
gethostans(struct irs_ho *this,
const u_char *ansbuf, int anslen, const char *qname, int qtype,
int af, int size, /* meaningless for addrinfo cases */
struct addrinfo **ret_aip, const struct addrinfo *pai)
{
struct pvt *pvt = (struct pvt *)this->private;
int type, class, ancount, qdcount, n, haveanswer, had_error;
int error = NETDB_SUCCESS, arcount;
int (*name_ok)(const char *);
const HEADER *hp;
const u_char *eom;
const u_char *eor;
const u_char *cp;
const char *tname;
const char *hname;
char *bp, *ep, **ap, **hap;
char tbuf[MAXDNAME+1];
struct addrinfo sentinel, *cur, ai;
if (pai == NULL) abort();
if (ret_aip != NULL)
*ret_aip = NULL;
memset(&sentinel, 0, sizeof(sentinel));
cur = &sentinel;
tname = qname;
eom = ansbuf + anslen;
switch (qtype) {
case T_A:
case T_AAAA:
case T_ANY: /* use T_ANY only for T_A/T_AAAA lookup */
name_ok = res_hnok;
break;
case T_PTR:
name_ok = res_dnok;
break;
default:
abort();
}
pvt->host.h_addrtype = af;
pvt->host.h_length = size;
hname = pvt->host.h_name = NULL;
/*
* Find first satisfactory answer.
*/
if (ansbuf + HFIXEDSZ > eom) {
RES_SET_H_ERRNO(pvt->res, NO_RECOVERY);
return (NULL);
}
hp = (const HEADER *)ansbuf;
ancount = ntohs(hp->ancount);
qdcount = ntohs(hp->qdcount);
arcount = ntohs(hp->arcount);
bp = pvt->hostbuf;
ep = pvt->hostbuf + sizeof(pvt->hostbuf);
cp = ansbuf + HFIXEDSZ;
if (qdcount != 1) {
RES_SET_H_ERRNO(pvt->res, NO_RECOVERY);
return (NULL);
}
n = dn_expand(ansbuf, eom, cp, bp, ep - bp);
if (n < 0 || !maybe_ok(pvt->res, bp, name_ok)) {
RES_SET_H_ERRNO(pvt->res, NO_RECOVERY);
return (NULL);
}
cp += n + QFIXEDSZ;
if (cp > eom) {
RES_SET_H_ERRNO(pvt->res, NO_RECOVERY);
return (NULL);
}
if (qtype == T_A || qtype == T_AAAA || qtype == T_ANY) {
/* res_nsend() has already verified that the query name is the
* same as the one we sent; this just gets the expanded name
* (i.e., with the succeeding search-domain tacked on).
*/
n = strlen(bp) + 1; /* for the \0 */
if (n > MAXHOSTNAMELEN) {
RES_SET_H_ERRNO(pvt->res, NO_RECOVERY);
return (NULL);
}
pvt->host.h_name = bp;
hname = bp;
bp += n;
/* The qname can be abbreviated, but hname is now absolute. */
qname = pvt->host.h_name;
}
ap = pvt->host_aliases;
*ap = NULL;
pvt->host.h_aliases = pvt->host_aliases;
hap = pvt->h_addr_ptrs;
*hap = NULL;
pvt->host.h_addr_list = pvt->h_addr_ptrs;
haveanswer = 0;
had_error = 0;
while (ancount-- > 0 && cp < eom && !had_error) {
n = dn_expand(ansbuf, eom, cp, bp, ep - bp);
if (n < 0 || !maybe_ok(pvt->res, bp, name_ok)) {
had_error++;
continue;
}
cp += n; /* name */
BOUNDS_CHECK(cp, 3 * INT16SZ + INT32SZ);
type = ns_get16(cp);
cp += INT16SZ; /* type */
class = ns_get16(cp);
cp += INT16SZ + INT32SZ; /* class, TTL */
n = ns_get16(cp);
cp += INT16SZ; /* len */
BOUNDS_CHECK(cp, n);
if (class != C_IN) {
cp += n;
continue;
}
eor = cp + n;
if ((qtype == T_A || qtype == T_AAAA || qtype == T_ANY) &&
type == T_CNAME) {
if (haveanswer) {
int level = LOG_CRIT;
#ifdef LOG_SECURITY
level |= LOG_SECURITY;
#endif
syslog(level,
"gethostans: possible attempt to exploit buffer overflow while looking up %s",
*qname ? qname : ".");
}
n = dn_expand(ansbuf, eor, cp, tbuf, sizeof tbuf);
if (n < 0 || !maybe_ok(pvt->res, tbuf, name_ok)) {
had_error++;
continue;
}
cp += n;
/* Store alias. */
if (ap >= &pvt->host_aliases[MAXALIASES-1])
continue;
*ap++ = bp;
n = strlen(bp) + 1; /* for the \0 */
bp += n;
/* Get canonical name. */
n = strlen(tbuf) + 1; /* for the \0 */
if (n > (ep - bp) || n > MAXHOSTNAMELEN) {
had_error++;
continue;
}
#ifdef HAVE_STRLCPY
strlcpy(bp, tbuf, ep - bp);
#else
strcpy(bp, tbuf);
#endif
pvt->host.h_name = bp;
hname = bp;
bp += n;
continue;
}
if (qtype == T_PTR && type == T_CNAME) {
n = dn_expand(ansbuf, eor, cp, tbuf, sizeof tbuf);
if (n < 0 || !maybe_dnok(pvt->res, tbuf)) {
had_error++;
continue;
}
cp += n;
#ifdef RES_USE_DNAME
if ((pvt->res->options & RES_USE_DNAME) != 0)
#endif
{
/*
* We may be able to check this regardless
* of the USE_DNAME bit, but we add the check
* for now since the DNAME support is
* experimental.
*/
if (ns_samename(tname, bp) != 1)
continue;
}
/* Get canonical name. */
n = strlen(tbuf) + 1; /* for the \0 */
if (n > (ep - bp)) {
had_error++;
continue;
}
#ifdef HAVE_STRLCPY
strlcpy(bp, tbuf, ep - bp);
#else
strcpy(bp, tbuf);
#endif
tname = bp;
bp += n;
continue;
}
if (qtype == T_ANY) {
if (!(type == T_A || type == T_AAAA)) {
cp += n;
continue;
}
} else if (type != qtype) {
cp += n;
continue;
}
switch (type) {
case T_PTR:
if (ret_aip != NULL) {
/* addrinfo never needs T_PTR */
cp += n;
continue;
}
if (ns_samename(tname, bp) != 1) {
cp += n;
continue;
}
n = dn_expand(ansbuf, eor, cp, bp, ep - bp);
if (n < 0 || !maybe_hnok(pvt->res, bp) ||
n >= MAXHOSTNAMELEN) {
had_error++;
break;
}
cp += n;
if (!haveanswer) {
pvt->host.h_name = bp;
hname = bp;
}
else if (ap < &pvt->host_aliases[MAXALIASES-1])
*ap++ = bp;
else
n = -1;
if (n != -1) {
n = strlen(bp) + 1; /* for the \0 */
bp += n;
}
break;
case T_A:
case T_AAAA:
if (ns_samename(hname, bp) != 1) {
cp += n;
continue;
}
if (type == T_A && n != INADDRSZ) {
cp += n;
continue;
}
if (type == T_AAAA && n != IN6ADDRSZ) {
cp += n;
continue;
}
/* make addrinfo. don't overwrite constant PAI */
ai = *pai;
ai.ai_family = (type == T_AAAA) ? AF_INET6 : AF_INET;
cur->ai_next = addr2addrinfo(
(const struct addrinfo *)&ai,
(const char *)cp);
if (cur->ai_next == NULL)
had_error++;
if (!haveanswer) {
int nn;
nn = strlen(bp) + 1; /* for the \0 */
if (nn >= MAXHOSTNAMELEN) {
cp += n;
had_error++;
continue;
}
pvt->host.h_name = bp;
hname = bp;
bp += nn;
}
/* Ensure alignment. */
bp = (char *)(((u_long)bp + (sizeof(align) - 1)) &
~(sizeof(align) - 1));
/* Avoid overflows. */
if (bp + n >= &pvt->hostbuf[sizeof pvt->hostbuf]) {
had_error++;
continue;
}
if (ret_aip) { /* need addrinfo. keep it. */
while (cur && cur->ai_next)
cur = cur->ai_next;
} else if (cur->ai_next) { /* need hostent */
struct addrinfo *aip = cur->ai_next;
for (aip = cur->ai_next; aip;
aip = aip->ai_next) {
int m;
m = add_hostent(pvt, bp, hap, aip);
if (m < 0) {
had_error++;
break;
}
if (m == 0)
continue;
if (hap < &pvt->h_addr_ptrs[MAXADDRS-1])
hap++;
*hap = NULL;
bp += m;
}
freeaddrinfo(cur->ai_next);
cur->ai_next = NULL;
}
cp += n;
break;
default:
abort();
}
if (!had_error)
haveanswer++;
}
if (haveanswer) {
if (ret_aip == NULL) {
*ap = NULL;
*hap = NULL;
if (pvt->res->nsort && haveanswer > 1 && qtype == T_A)
addrsort(pvt->res, pvt->h_addr_ptrs,
haveanswer);
if (pvt->host.h_name == NULL) {
n = strlen(qname) + 1; /* for the \0 */
if (n > (ep - bp) || n >= MAXHOSTNAMELEN)
goto no_recovery;
#ifdef HAVE_STRLCPY
strlcpy(bp, qname, ep - bp);
#else
strcpy(bp, qname);
#endif
pvt->host.h_name = bp;
bp += n;
}
if (pvt->res->options & RES_USE_INET6)
map_v4v6_hostent(&pvt->host, &bp, ep);
RES_SET_H_ERRNO(pvt->res, NETDB_SUCCESS);
return (&pvt->host);
} else {
if ((pai->ai_flags & AI_CANONNAME) != 0) {
if (pvt->host.h_name == NULL) {
sentinel.ai_next->ai_canonname =
strdup(qname);
}
else {
sentinel.ai_next->ai_canonname =
strdup(pvt->host.h_name);
}
}
*ret_aip = sentinel.ai_next;
return(NULL);
}
}
no_recovery:
if (sentinel.ai_next) {
/* this should be impossible, but check it for safety */
freeaddrinfo(sentinel.ai_next);
}
if (error == NETDB_SUCCESS)
RES_SET_H_ERRNO(pvt->res, NO_RECOVERY);
else
RES_SET_H_ERRNO(pvt->res, error);
return(NULL);
}
static int
add_hostent(struct pvt *pvt, char *bp, char **hap, struct addrinfo *ai)
{
int addrlen;
char *addrp;
const char **tap;
char *obp = bp;
switch(ai->ai_addr->sa_family) {
case AF_INET6:
addrlen = IN6ADDRSZ;
addrp = (char *)&((struct sockaddr_in6 *)ai->ai_addr)->sin6_addr;
break;
case AF_INET:
addrlen = INADDRSZ;
addrp = (char *)&((struct sockaddr_in *)ai->ai_addr)->sin_addr;
break;
default:
return(-1); /* abort? */
}
/* Ensure alignment. */
bp = (char *)(((u_long)bp + (sizeof(align) - 1)) &
~(sizeof(align) - 1));
/* Avoid overflows. */
if (bp + addrlen >= &pvt->hostbuf[sizeof pvt->hostbuf])
return(-1);
if (hap >= &pvt->h_addr_ptrs[MAXADDRS-1])
return(0); /* fail, but not treat it as an error. */
/* Suppress duplicates. */
for (tap = (const char **)pvt->h_addr_ptrs;
*tap != NULL;
tap++)
if (memcmp(*tap, addrp, addrlen) == 0)
break;
if (*tap != NULL)
return (0);
memcpy(*hap = bp, addrp, addrlen);
return((bp + addrlen) - obp);
}
static void
map_v4v6_hostent(struct hostent *hp, char **bpp, char *ep) {
char **ap;
if (hp->h_addrtype != AF_INET || hp->h_length != INADDRSZ)
return;
hp->h_addrtype = AF_INET6;
hp->h_length = IN6ADDRSZ;
for (ap = hp->h_addr_list; *ap; ap++) {
int i = (u_long)*bpp % sizeof(align);
if (i != 0)
i = sizeof(align) - i;
if ((ep - *bpp) < (i + IN6ADDRSZ)) {
/* Out of memory. Truncate address list here. */
*ap = NULL;
return;
}
*bpp += i;
map_v4v6_address(*ap, *bpp);
*ap = *bpp;
*bpp += IN6ADDRSZ;
}
}
static void
addrsort(res_state statp, char **ap, int num) {
int i, j, needsort = 0, aval[MAXADDRS];
char **p;
p = ap;
for (i = 0; i < num; i++, p++) {
for (j = 0 ; (unsigned)j < statp->nsort; j++)
if (statp->sort_list[j].addr.s_addr ==
(((struct in_addr *)(*p))->s_addr &
statp->sort_list[j].mask))
break;
aval[i] = j;
if (needsort == 0 && i > 0 && j < aval[i-1])
needsort = i;
}
if (!needsort)
return;
while (needsort < num) {
for (j = needsort - 1; j >= 0; j--) {
if (aval[j] > aval[j+1]) {
char *hp;
i = aval[j];
aval[j] = aval[j+1];
aval[j+1] = i;
hp = ap[j];
ap[j] = ap[j+1];
ap[j+1] = hp;
} else
break;
}
needsort++;
}
}
static int
init(struct irs_ho *this) {
struct pvt *pvt = (struct pvt *)this->private;
if (!pvt->res && !ho_res_get(this))
return (-1);
if (((pvt->res->options & RES_INIT) == 0) &&
res_ninit(pvt->res) == -1)
return (-1);
return (0);
}
Reference in New Issue View Git Blame Copy Permalink