/*-
* SPDX-License-Identifier: BSD-4-Clause
*
* Copyright (c) 1995
* Bill Paul <wpaul@ctr.columbia.edu>. 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Bill Paul.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY Bill Paul 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 Bill Paul 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 <sys/cdefs.h>
#include <stdlib.h>
#include <rpc/rpc.h>
#include <rpcsvc/yp.h>
#include <rpcsvc/yppasswd.h>
#include <rpcsvc/ypxfrd.h>
#include <sys/types.h>
#include <limits.h>
#include <db.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/stat.h>
#include <sys/fcntl.h>
#include <paths.h>
#include <errno.h>
#include <sys/param.h>
#include "yp_extern.h"
#ifdef TCP_WRAPPER
#include "tcpd.h"
#endif
static const char *yp_procs[] = {
/* NIS v1 */
"ypoldproc_null",
"ypoldproc_domain",
"ypoldproc_domain_nonack",
"ypoldproc_match",
"ypoldproc_first",
"ypoldproc_next",
"ypoldproc_poll",
"ypoldproc_push",
"ypoldproc_get",
"badproc1", /* placeholder */
"badproc2", /* placeholder */
"badproc3", /* placeholder */
/* NIS v2 */
"ypproc_null",
"ypproc_domain",
"ypproc_domain_nonack",
"ypproc_match",
"ypproc_first",
"ypproc_next",
"ypproc_xfr",
"ypproc_clear",
"ypproc_all",
"ypproc_master",
"ypproc_order",
"ypproc_maplist"
};
struct securenet {
struct in_addr net;
struct in_addr mask;
struct securenet *next;
};
static struct securenet *securenets;
#define LINEBUFSZ 1024
#ifdef TCP_WRAPPER
int hosts_ctl(char *, char *, char *, char *);
#endif
/*
* Read /var/yp/securenets file and initialize the securenets
* list. If the file doesn't exist, we set up a dummy entry that
* allows all hosts to connect.
*/
void
load_securenets(void)
{
FILE *fp;
char path[MAXPATHLEN + 2];
char linebuf[1024 + 2];
struct securenet *tmp;
/*
* If securenets is not NULL, we are being called to reload
* the list; free the existing list before re-reading the
* securenets file.
*/
while (securenets) {
tmp = securenets->next;
free(securenets);
securenets = tmp;
}
snprintf(path, MAXPATHLEN, "%s/securenets", yp_dir);
if ((fp = fopen(path, "r")) == NULL) {
if (errno == ENOENT) {
securenets = malloc(sizeof(struct securenet));
securenets->net.s_addr = INADDR_ANY;
securenets->mask.s_addr = INADDR_ANY;
securenets->next = NULL;
return;
} else {
yp_error("fopen(%s) failed: %s", path, strerror(errno));
exit(1);
}
}
securenets = NULL;
while (fgets(linebuf, LINEBUFSZ, fp)) {
char addr1[20], addr2[20];
if ((linebuf[0] == '#')
|| (strspn(linebuf, " \t\r\n") == strlen(linebuf)))
continue;
if (sscanf(linebuf, "%s %s", addr1, addr2) < 2) {
yp_error("badly formatted securenets entry: %s",
linebuf);
continue;
}
tmp = malloc(sizeof(struct securenet));
if (!inet_aton((char *)&addr1, (struct in_addr *)&tmp->net)) {
yp_error("badly formatted securenets entry: %s", addr1);
free(tmp);
continue;
}
if (!inet_aton((char *)&addr2, (struct in_addr *)&tmp->mask)) {
yp_error("badly formatted securenets entry: %s", addr2);
free(tmp);
continue;
}
tmp->next = securenets;
securenets = tmp;
}
fclose(fp);
}
/*
* Access control functions.
*
* yp_access() checks the mapname and client host address and watches for
* the following things:
*
* - If the client is referencing one of the master.passwd.* or shadow.* maps,
* it must be using a privileged port to make its RPC to us. If it is, then
* we can assume that the caller is root and allow the RPC to succeed. If it
* isn't access is denied.
*
* - The client's IP address is checked against the securenets rules.
* There are two kinds of securenets support: the built-in support,
* which is very simple and depends on the presence of a
* /var/yp/securenets file, and tcp-wrapper support, which requires
* Wietse Venema's libwrap.a and tcpd.h. (Since the tcp-wrapper
* package does not ship with FreeBSD, we use the built-in support
* by default. Users can recompile the server with the tcp-wrapper library
* if they already have it installed and want to use hosts.allow and
* hosts.deny to control access instead of having a separate securenets
* file.)
*
* If no /var/yp/securenets file is present, the host access checks
* are bypassed and all hosts are allowed to connect.
*
* The yp_validdomain() function checks the domain specified by the caller
* to make sure it's actually served by this server. This is more a sanity
* check than an a security check, but this seems to be the best place for
* it.
*/
#ifdef DB_CACHE
int
yp_access(const char *map, const char *domain, const struct svc_req *rqstp)
#else
int
yp_access(const char *map, const struct svc_req *rqstp)
#endif
{
struct sockaddr_in *rqhost;
int status_securenets = 0;
#ifdef TCP_WRAPPER
int status_tcpwrap;
#endif
static unsigned long oldaddr = 0;
struct securenet *tmp;
const char *yp_procedure = NULL;
char procbuf[50];
if (rqstp->rq_prog != YPPASSWDPROG && rqstp->rq_prog != YPPROG) {
snprintf(procbuf, sizeof(procbuf), "#%lu/#%lu",
(unsigned long)rqstp->rq_prog,
(unsigned long)rqstp->rq_proc);
yp_procedure = (char *)&procbuf;
} else {
yp_procedure = rqstp->rq_prog == YPPASSWDPROG ?
"yppasswdprog_update" :
yp_procs[rqstp->rq_proc + (12 * (rqstp->rq_vers - 1))];
}
rqhost = svc_getcaller(rqstp->rq_xprt);
if (debug) {
yp_error("procedure %s called from %s:%d", yp_procedure,
inet_ntoa(rqhost->sin_addr),
ntohs(rqhost->sin_port));
if (map != NULL)
yp_error("client is referencing map \"%s\".", map);
}
/* Check the map name if one was supplied. */
if (map != NULL) {
if (strchr(map, '/')) {
yp_error("embedded slash in map name \"%s\" -- \
possible spoof attempt from %s:%d",
map, inet_ntoa(rqhost->sin_addr),
ntohs(rqhost->sin_port));
return(1);
}
#ifdef DB_CACHE
if ((yp_testflag((char *)map, (char *)domain, YP_SECURE) ||
#else
if ((strstr(map, "master.passwd.") || strstr(map, "shadow.") ||
#endif
(rqstp->rq_prog == YPPROG &&
rqstp->rq_proc == YPPROC_XFR) ||
(rqstp->rq_prog == YPXFRD_FREEBSD_PROG &&
rqstp->rq_proc == YPXFRD_GETMAP)) &&
ntohs(rqhost->sin_port) >= IPPORT_RESERVED) {
yp_error("access to %s denied -- client %s:%d \
not privileged", map, inet_ntoa(rqhost->sin_addr), ntohs(rqhost->sin_port));
return(1);
}
}
#ifdef TCP_WRAPPER
status_tcpwrap = hosts_ctl("ypserv", STRING_UNKNOWN,
inet_ntoa(rqhost->sin_addr), "");
#endif
tmp = securenets;
while (tmp) {
if (((rqhost->sin_addr.s_addr & ~tmp->mask.s_addr)
| tmp->net.s_addr) == rqhost->sin_addr.s_addr) {
status_securenets = 1;
break;
}
tmp = tmp->next;
}
#ifdef TCP_WRAPPER
if (status_securenets == 0 || status_tcpwrap == 0) {
#else
if (status_securenets == 0) {
#endif
/*
* One of the following two events occurred:
*
* (1) The /var/yp/securenets exists and the remote host does not
* match any of the networks specified in it.
* (2) The hosts.allow file has denied access and TCP_WRAPPER is
* defined.
*
* In either case deny access.
*/
if (rqhost->sin_addr.s_addr != oldaddr) {
yp_error("connect from %s:%d to procedure %s refused",
inet_ntoa(rqhost->sin_addr),
ntohs(rqhost->sin_port),
yp_procedure);
oldaddr = rqhost->sin_addr.s_addr;
}
return(1);
}
return(0);
}
int
yp_validdomain(const char *domain)
{
struct stat statbuf;
char dompath[MAXPATHLEN + 2];
if (domain == NULL || strstr(domain, "binding") ||
!strcmp(domain, ".") || !strcmp(domain, "..") ||
strchr(domain, '/') || strlen(domain) > YPMAXDOMAIN)
return(1);
snprintf(dompath, sizeof(dompath), "%s/%s", yp_dir, domain);
if (stat(dompath, &statbuf) < 0 || !S_ISDIR(statbuf.st_mode))
return(1);
return(0);
}
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