8053080cbc
Now when tcp_wrapper is enabled by inetd -wW,
several accesses which should be permitted are refused only for IPv6,
if hostname is used to decide the host to be allowed.
IPv6 users will be just upset.
About security related concern.
-All extensions are wrapped by #ifdef INET6, so people can completely
disable the extension by recompile libwrap without INET6 option.
-Access via IPv6 is not enabled by default.
People need to enable IPv6 access by changing /etc/inetd.conf at first,
by adding tcp6 and/or tcp46 entries.
-The base of patches are from KAME package and are actually daily used
for more than a year in several Japanese IPv6 environments.
-Patches are reviewed by markm.
Approved by: jkh
Submitted by: Hajimu UMEMOTO <ume@mahoroba.org>
Reviewed by: markm
Obtained from: KAME project
385 lines
10 KiB
C
385 lines
10 KiB
C
/*
|
|
* This module determines the type of socket (datagram, stream), the client
|
|
* socket address and port, the server socket address and port. In addition,
|
|
* it provides methods to map a transport address to a printable host name
|
|
* or address. Socket address information results are in static memory.
|
|
*
|
|
* The result from the hostname lookup method is STRING_PARANOID when a host
|
|
* pretends to have someone elses name, or when a host name is available but
|
|
* could not be verified.
|
|
*
|
|
* When lookup or conversion fails the result is set to STRING_UNKNOWN.
|
|
*
|
|
* Diagnostics are reported through syslog(3).
|
|
*
|
|
* Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
|
|
*
|
|
* $FreeBSD$
|
|
*/
|
|
|
|
#ifndef lint
|
|
static char sccsid[] = "@(#) socket.c 1.15 97/03/21 19:27:24";
|
|
#endif
|
|
|
|
/* System libraries. */
|
|
|
|
#include <sys/types.h>
|
|
#include <sys/param.h>
|
|
#include <sys/socket.h>
|
|
#include <netinet/in.h>
|
|
#include <netdb.h>
|
|
#include <stdio.h>
|
|
#include <syslog.h>
|
|
#include <string.h>
|
|
|
|
#ifdef INET6
|
|
#ifndef USE_GETIPNODEBY
|
|
#include <resolv.h>
|
|
#endif
|
|
#endif
|
|
|
|
extern char *inet_ntoa();
|
|
|
|
/* Local stuff. */
|
|
|
|
#include "tcpd.h"
|
|
|
|
/* Forward declarations. */
|
|
|
|
static void sock_sink();
|
|
|
|
#ifdef APPEND_DOT
|
|
|
|
/*
|
|
* Speed up DNS lookups by terminating the host name with a dot. Should be
|
|
* done with care. The speedup can give problems with lookups from sources
|
|
* that lack DNS-style trailing dot magic, such as local files or NIS maps.
|
|
*/
|
|
|
|
static struct hostent *gethostbyname_dot(name)
|
|
char *name;
|
|
{
|
|
char dot_name[MAXHOSTNAMELEN + 1];
|
|
|
|
/*
|
|
* Don't append dots to unqualified names. Such names are likely to come
|
|
* from local hosts files or from NIS.
|
|
*/
|
|
|
|
if (strchr(name, '.') == 0 || strlen(name) >= MAXHOSTNAMELEN - 1) {
|
|
return (gethostbyname(name));
|
|
} else {
|
|
sprintf(dot_name, "%s.", name);
|
|
return (gethostbyname(dot_name));
|
|
}
|
|
}
|
|
|
|
#define gethostbyname gethostbyname_dot
|
|
#endif
|
|
|
|
/* sock_host - look up endpoint addresses and install conversion methods */
|
|
|
|
void sock_host(request)
|
|
struct request_info *request;
|
|
{
|
|
#ifdef INET6
|
|
static struct sockaddr_storage client;
|
|
static struct sockaddr_storage server;
|
|
#else
|
|
static struct sockaddr_in client;
|
|
static struct sockaddr_in server;
|
|
#endif
|
|
int len;
|
|
char buf[BUFSIZ];
|
|
int fd = request->fd;
|
|
|
|
sock_methods(request);
|
|
|
|
/*
|
|
* Look up the client host address. Hal R. Brand <BRAND@addvax.llnl.gov>
|
|
* suggested how to get the client host info in case of UDP connections:
|
|
* peek at the first message without actually looking at its contents. We
|
|
* really should verify that client.sin_family gets the value AF_INET,
|
|
* but this program has already caused too much grief on systems with
|
|
* broken library code.
|
|
*/
|
|
|
|
len = sizeof(client);
|
|
if (getpeername(fd, (struct sockaddr *) & client, &len) < 0) {
|
|
request->sink = sock_sink;
|
|
len = sizeof(client);
|
|
if (recvfrom(fd, buf, sizeof(buf), MSG_PEEK,
|
|
(struct sockaddr *) & client, &len) < 0) {
|
|
tcpd_warn("can't get client address: %m");
|
|
return; /* give up */
|
|
}
|
|
#ifdef really_paranoid
|
|
memset(buf, 0 sizeof(buf));
|
|
#endif
|
|
}
|
|
#ifdef INET6
|
|
request->client->sin = (struct sockaddr *)&client;
|
|
#else
|
|
request->client->sin = &client;
|
|
#endif
|
|
|
|
/*
|
|
* Determine the server binding. This is used for client username
|
|
* lookups, and for access control rules that trigger on the server
|
|
* address or name.
|
|
*/
|
|
|
|
len = sizeof(server);
|
|
if (getsockname(fd, (struct sockaddr *) & server, &len) < 0) {
|
|
tcpd_warn("getsockname: %m");
|
|
return;
|
|
}
|
|
#ifdef INET6
|
|
request->server->sin = (struct sockaddr *)&server;
|
|
#else
|
|
request->server->sin = &server;
|
|
#endif
|
|
}
|
|
|
|
/* sock_hostaddr - map endpoint address to printable form */
|
|
|
|
void sock_hostaddr(host)
|
|
struct host_info *host;
|
|
{
|
|
#ifdef INET6
|
|
struct sockaddr *sin = host->sin;
|
|
char *ap;
|
|
int alen;
|
|
|
|
if (!sin)
|
|
return;
|
|
switch (sin->sa_family) {
|
|
case AF_INET:
|
|
ap = (char *)&((struct sockaddr_in *)sin)->sin_addr;
|
|
alen = sizeof(struct in_addr);
|
|
break;
|
|
case AF_INET6:
|
|
ap = (char *)&((struct sockaddr_in6 *)sin)->sin6_addr;
|
|
alen = sizeof(struct in6_addr);
|
|
break;
|
|
default:
|
|
return;
|
|
}
|
|
host->addr[0] = '\0';
|
|
inet_ntop(sin->sa_family, ap, host->addr, sizeof(host->addr));
|
|
#else
|
|
struct sockaddr_in *sin = host->sin;
|
|
|
|
if (sin != 0)
|
|
STRN_CPY(host->addr, inet_ntoa(sin->sin_addr), sizeof(host->addr));
|
|
#endif
|
|
}
|
|
|
|
/* sock_hostname - map endpoint address to host name */
|
|
|
|
void sock_hostname(host)
|
|
struct host_info *host;
|
|
{
|
|
#ifdef INET6
|
|
struct sockaddr *sin = host->sin;
|
|
char addr[128];
|
|
#ifdef USE_GETIPNODEBY
|
|
int h_error;
|
|
#else
|
|
u_long res_options;
|
|
#endif
|
|
struct hostent *hp = NULL;
|
|
char *ap;
|
|
int alen;
|
|
#else
|
|
struct sockaddr_in *sin = host->sin;
|
|
struct hostent *hp;
|
|
#endif
|
|
int i;
|
|
|
|
/*
|
|
* On some systems, for example Solaris 2.3, gethostbyaddr(0.0.0.0) does
|
|
* not fail. Instead it returns "INADDR_ANY". Unfortunately, this does
|
|
* not work the other way around: gethostbyname("INADDR_ANY") fails. We
|
|
* have to special-case 0.0.0.0, in order to avoid false alerts from the
|
|
* host name/address checking code below.
|
|
*/
|
|
#ifdef INET6
|
|
if (sin != NULL) {
|
|
switch (sin->sa_family) {
|
|
case AF_INET:
|
|
if (((struct sockaddr_in *)sin)->sin_addr.s_addr == 0) {
|
|
strcpy(host->name, paranoid); /* name is bad, clobber it */
|
|
return;
|
|
}
|
|
ap = (char *) &((struct sockaddr_in *)sin)->sin_addr;
|
|
alen = sizeof(struct in_addr);
|
|
break;
|
|
case AF_INET6:
|
|
ap = (char *) &((struct sockaddr_in6 *)sin)->sin6_addr;
|
|
alen = sizeof(struct in6_addr);
|
|
break;
|
|
defalut:
|
|
strcpy(host->name, paranoid); /* name is bad, clobber it */
|
|
return;
|
|
}
|
|
#ifdef USE_GETIPNODEBY
|
|
hp = getipnodebyaddr(ap, alen, sin->sa_family, &h_error);
|
|
#else
|
|
hp = gethostbyaddr(ap, alen, sin->sa_family);
|
|
#endif
|
|
}
|
|
if (hp) {
|
|
#else
|
|
if (sin != 0 && sin->sin_addr.s_addr != 0
|
|
&& (hp = gethostbyaddr((char *) &(sin->sin_addr),
|
|
sizeof(sin->sin_addr), AF_INET)) != 0) {
|
|
#endif
|
|
|
|
STRN_CPY(host->name, hp->h_name, sizeof(host->name));
|
|
#if defined(INET6) && defined(USE_GETIPNODEBY)
|
|
freehostent(hp);
|
|
#endif
|
|
|
|
/*
|
|
* Verify that the address is a member of the address list returned
|
|
* by gethostbyname(hostname).
|
|
*
|
|
* Verify also that gethostbyaddr() and gethostbyname() return the same
|
|
* hostname, or rshd and rlogind may still end up being spoofed.
|
|
*
|
|
* On some sites, gethostbyname("localhost") returns "localhost.domain".
|
|
* This is a DNS artefact. We treat it as a special case. When we
|
|
* can't believe the address list from gethostbyname("localhost")
|
|
* we're in big trouble anyway.
|
|
*/
|
|
|
|
#ifdef INET6
|
|
#ifdef USE_GETIPNODEBY
|
|
hp = getipnodebyname(host->name, sin->sa_family,
|
|
AI_V4MAPPED | AI_ADDRCONFIG | AI_ALL, &h_error);
|
|
#else
|
|
if ((_res.options & RES_INIT) == 0) {
|
|
if (res_init() < 0) {
|
|
inet_ntop(sin->sa_family, ap, addr, sizeof(addr));
|
|
tcpd_warn("can't verify hostname: res_init() for %s failed",
|
|
addr);
|
|
strcpy(host->name, paranoid); /* name is bad, clobber it */
|
|
return;
|
|
}
|
|
}
|
|
res_options = _res.options;
|
|
if (sin->sa_family == AF_INET6)
|
|
_res.options |= RES_USE_INET6;
|
|
else
|
|
_res.options &= ~RES_USE_INET6;
|
|
hp = gethostbyname2(host->name,
|
|
(sin->sa_family == AF_INET6 &&
|
|
IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)sin)->sin6_addr)) ?
|
|
AF_INET : sin->sa_family);
|
|
_res.options = res_options;
|
|
#endif
|
|
if (!hp) {
|
|
#else
|
|
if ((hp = gethostbyname(host->name)) == 0) {
|
|
#endif
|
|
|
|
/*
|
|
* Unable to verify that the host name matches the address. This
|
|
* may be a transient problem or a botched name server setup.
|
|
*/
|
|
|
|
#ifdef INET6
|
|
#ifdef USE_GETIPNODEBY
|
|
tcpd_warn("can't verify hostname: getipnodebyname(%s, %s) failed",
|
|
#else
|
|
tcpd_warn("can't verify hostname: gethostbyname2(%s, %s) failed",
|
|
#endif
|
|
host->name,
|
|
(sin->sa_family == AF_INET) ? "AF_INET" : "AF_INET6");
|
|
#else
|
|
tcpd_warn("can't verify hostname: gethostbyname(%s) failed",
|
|
host->name);
|
|
#endif
|
|
|
|
} else if (STR_NE(host->name, hp->h_name)
|
|
&& STR_NE(host->name, "localhost")) {
|
|
|
|
/*
|
|
* The gethostbyaddr() and gethostbyname() calls did not return
|
|
* the same hostname. This could be a nameserver configuration
|
|
* problem. It could also be that someone is trying to spoof us.
|
|
*/
|
|
|
|
tcpd_warn("host name/name mismatch: %s != %.*s",
|
|
host->name, STRING_LENGTH, hp->h_name);
|
|
|
|
} else {
|
|
|
|
/*
|
|
* The address should be a member of the address list returned by
|
|
* gethostbyname(). We should first verify that the h_addrtype
|
|
* field is AF_INET, but this program has already caused too much
|
|
* grief on systems with broken library code.
|
|
*/
|
|
|
|
for (i = 0; hp->h_addr_list[i]; i++) {
|
|
#ifdef INET6
|
|
if (memcmp(hp->h_addr_list[i], ap, alen) == 0) {
|
|
#ifdef USE_GETIPNODEBY
|
|
freehostent(hp);
|
|
#endif
|
|
return; /* name is good, keep it */
|
|
}
|
|
#else
|
|
if (memcmp(hp->h_addr_list[i],
|
|
(char *) &sin->sin_addr,
|
|
sizeof(sin->sin_addr)) == 0)
|
|
return; /* name is good, keep it */
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* The host name does not map to the initial address. Perhaps
|
|
* someone has messed up. Perhaps someone compromised a name
|
|
* server.
|
|
*/
|
|
|
|
#ifdef INET6
|
|
inet_ntop(sin->sa_family, ap, addr, sizeof(addr));
|
|
tcpd_warn("host name/address mismatch: %s != %.*s",
|
|
addr, STRING_LENGTH, hp->h_name);
|
|
#else
|
|
tcpd_warn("host name/address mismatch: %s != %.*s",
|
|
inet_ntoa(sin->sin_addr), STRING_LENGTH, hp->h_name);
|
|
#endif
|
|
}
|
|
strcpy(host->name, paranoid); /* name is bad, clobber it */
|
|
#if defined(INET6) && defined(USE_GETIPNODEBY)
|
|
if (hp)
|
|
freehostent(hp);
|
|
#endif
|
|
}
|
|
}
|
|
|
|
/* sock_sink - absorb unreceived IP datagram */
|
|
|
|
static void sock_sink(fd)
|
|
int fd;
|
|
{
|
|
char buf[BUFSIZ];
|
|
#ifdef INET6
|
|
struct sockaddr_storage sin;
|
|
#else
|
|
struct sockaddr_in sin;
|
|
#endif
|
|
int size = sizeof(sin);
|
|
|
|
/*
|
|
* Eat up the not-yet received datagram. Some systems insist on a
|
|
* non-zero source address argument in the recvfrom() call below.
|
|
*/
|
|
|
|
(void) recvfrom(fd, buf, sizeof(buf), 0, (struct sockaddr *) & sin, &size);
|
|
}
|