yp_access.c revision 21366
112891Swpaul/* 212891Swpaul * Copyright (c) 1995 312891Swpaul * Bill Paul <wpaul@ctr.columbia.edu>. All rights reserved. 412891Swpaul * 512891Swpaul * Redistribution and use in source and binary forms, with or without 612891Swpaul * modification, are permitted provided that the following conditions 712891Swpaul * are met: 812891Swpaul * 1. Redistributions of source code must retain the above copyright 912891Swpaul * notice, this list of conditions and the following disclaimer. 1012891Swpaul * 2. Redistributions in binary form must reproduce the above copyright 1112891Swpaul * notice, this list of conditions and the following disclaimer in the 1212891Swpaul * documentation and/or other materials provided with the distribution. 1312891Swpaul * 3. All advertising materials mentioning features or use of this software 1412891Swpaul * must display the following acknowledgement: 1512891Swpaul * This product includes software developed by Bill Paul. 1612891Swpaul * 4. Neither the name of the author nor the names of any co-contributors 1712891Swpaul * may be used to endorse or promote products derived from this software 1812891Swpaul * without specific prior written permission. 1912891Swpaul * 2012891Swpaul * THIS SOFTWARE IS PROVIDED BY Bill Paul AND CONTRIBUTORS ``AS IS'' AND 2112891Swpaul * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 2212891Swpaul * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 2312891Swpaul * ARE DISCLAIMED. IN NO EVENT SHALL Bill Paul OR CONTRIBUTORS BE LIABLE 2412891Swpaul * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 2512891Swpaul * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 2612891Swpaul * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2712891Swpaul * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2812891Swpaul * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 2912891Swpaul * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 3012891Swpaul * SUCH DAMAGE. 3112891Swpaul * 3212891Swpaul */ 3312891Swpaul 3414248Swpaul#include <stdlib.h> 3512891Swpaul#include <rpc/rpc.h> 3614240Swpaul#include <rpcsvc/yp.h> 3714240Swpaul#include <rpcsvc/yppasswd.h> 3818586Swpaul#include <rpcsvc/ypxfrd.h> 3912891Swpaul#include <sys/types.h> 4015426Swpaul#include <limits.h> 4115426Swpaul#include <db.h> 4212891Swpaul#include <sys/socket.h> 4312891Swpaul#include <netinet/in.h> 4412891Swpaul#include <arpa/inet.h> 4512891Swpaul#include <sys/stat.h> 4615426Swpaul#include <sys/fcntl.h> 4712891Swpaul#include <paths.h> 4814240Swpaul#include <errno.h> 4912891Swpaul#include <sys/param.h> 5012891Swpaul#include "yp_extern.h" 5112891Swpaul#ifdef TCP_WRAPPER 5212891Swpaul#include "tcpd.h" 5312891Swpaul#endif 5412891Swpaul 5514240Swpaul#ifndef lint 5621366Swpaulstatic const char rcsid[] = "$Id: yp_access.c,v 1.11 1996/10/24 18:58:22 wpaul Exp $"; 5714240Swpaul#endif 5814240Swpaul 5912891Swpaulextern int debug; 6012891Swpaul 6114262Swpaul /* NIS v1 */ 6214262Swpaulchar *yp_procs[] = { "ypoldproc_null", 6314262Swpaul "ypoldproc_domain", 6414262Swpaul "ypoldproc_domain_nonack", 6514262Swpaul "ypoldproc_match", 6614262Swpaul "ypoldproc_first", 6714262Swpaul "ypoldproc_next", 6814262Swpaul "ypoldproc_poll", 6914262Swpaul "ypoldproc_push", 7014262Swpaul "ypoldproc_get", 7114262Swpaul "badproc1", /* placeholder */ 7214262Swpaul "badproc2", /* placeholder */ 7314262Swpaul "badproc3", /* placeholder */ 7414262Swpaul 7514262Swpaul /* NIS v2 */ 7614262Swpaul "ypproc_null" , 7712891Swpaul "ypproc_domain", 7812891Swpaul "ypproc_domain_nonack", 7912891Swpaul "ypproc_match", 8012891Swpaul "ypproc_first", 8112891Swpaul "ypproc_next", 8212891Swpaul "ypproc_xfr", 8312891Swpaul "ypproc_clear", 8412891Swpaul "ypproc_all", 8512891Swpaul "ypproc_master", 8612891Swpaul "ypproc_order", 8712891Swpaul "ypproc_maplist" 8812891Swpaul }; 8912891Swpaul 9014262Swpaul 9114240Swpaul#ifdef TCP_WRAPPER 9214240Swpaulvoid load_securenets() 9314240Swpaul{ 9414240Swpaul} 9514240Swpaul#else 9614240Swpaulstruct securenet { 9714240Swpaul struct in_addr net; 9814240Swpaul struct in_addr mask; 9914240Swpaul struct securenet *next; 10014240Swpaul}; 10114240Swpaul 10214240Swpaulstruct securenet *securenets; 10314240Swpaul 10414240Swpaul#define LINEBUFSZ 1024 10514240Swpaul 10612891Swpaul/* 10714240Swpaul * Read /var/yp/securenets file and initialize the securenets 10814240Swpaul * list. If the file doesn't exist, we set up a dummy entry that 10914240Swpaul * allows all hosts to connect. 11014240Swpaul */ 11114240Swpaulvoid load_securenets() 11214240Swpaul{ 11314240Swpaul FILE *fp; 11414240Swpaul char path[MAXPATHLEN + 2]; 11514240Swpaul char linebuf[1024 + 2]; 11614240Swpaul struct securenet *tmp; 11714240Swpaul 11814240Swpaul /* 11914240Swpaul * If securenets is not NULL, we are being called to reload 12014240Swpaul * the list; free the existing list before re-reading the 12114240Swpaul * securenets file. 12214240Swpaul */ 12315426Swpaul while(securenets) { 12415426Swpaul tmp = securenets->next; 12515426Swpaul free(securenets); 12615426Swpaul securenets = tmp; 12714240Swpaul } 12814240Swpaul 12914240Swpaul snprintf(path, MAXPATHLEN, "%s/securenets", yp_dir); 13014240Swpaul 13114240Swpaul if ((fp = fopen(path, "r")) == NULL) { 13214240Swpaul if (errno == ENOENT) { 13314240Swpaul securenets = (struct securenet *)malloc(sizeof(struct securenet)); 13414240Swpaul securenets->net.s_addr = INADDR_ANY; 13514302Sadam securenets->mask.s_addr = INADDR_ANY; 13614240Swpaul securenets->next = NULL; 13714240Swpaul return; 13814240Swpaul } else { 13914240Swpaul yp_error("fopen(%s) failed: %s", path, strerror(errno)); 14014240Swpaul exit(1); 14114240Swpaul } 14214240Swpaul } 14314240Swpaul 14414240Swpaul securenets = NULL; 14514240Swpaul 14614240Swpaul while(fgets(linebuf, LINEBUFSZ, fp)) { 14714240Swpaul char addr1[20], addr2[20]; 14814240Swpaul 14914240Swpaul if (linebuf[0] == '#') 15014240Swpaul continue; 15114240Swpaul if (sscanf(linebuf, "%s %s", addr1, addr2) < 2) { 15214240Swpaul yp_error("badly formatted securenets entry: %s", 15314240Swpaul linebuf); 15414240Swpaul continue; 15514240Swpaul } 15614240Swpaul 15714240Swpaul tmp = (struct securenet *)malloc(sizeof(struct securenet)); 15814240Swpaul 15914240Swpaul if (!inet_aton((char *)&addr1, (struct in_addr *)&tmp->net)) { 16014240Swpaul yp_error("badly formatted securenets entry: %s", addr1); 16114240Swpaul free(tmp); 16214240Swpaul continue; 16314240Swpaul } 16414240Swpaul 16514240Swpaul if (!inet_aton((char *)&addr2, (struct in_addr *)&tmp->mask)) { 16614240Swpaul yp_error("badly formatted securenets entry: %s", addr2); 16714240Swpaul free(tmp); 16814240Swpaul continue; 16914240Swpaul } 17014240Swpaul 17114240Swpaul tmp->next = securenets; 17214240Swpaul securenets = tmp; 17314240Swpaul } 17414240Swpaul 17514240Swpaul fclose(fp); 17614240Swpaul 17714240Swpaul} 17814240Swpaul#endif 17914240Swpaul 18014240Swpaul/* 18112891Swpaul * Access control functions. 18212891Swpaul * 18312891Swpaul * yp_access() checks the mapname and client host address and watches for 18412891Swpaul * the following things: 18512891Swpaul * 18612891Swpaul * - If the client is referencing one of the master.passwd.* maps, it must 18712891Swpaul * be using a privileged port to make its RPC to us. If it is, then we can 18812891Swpaul * assume that the caller is root and allow the RPC to succeed. If it 18912891Swpaul * isn't access is denied. 19012891Swpaul * 19114240Swpaul * - The client's IP address is checked against the securenets rules. 19214240Swpaul * There are two kinds of securenets support: the built-in support, 19315426Swpaul * which is very simple and depends on the presence of a 19414240Swpaul * /var/yp/securenets file, and tcp-wrapper support, which requires 19514240Swpaul * Wietse Venema's libwrap.a and tcpd.h. (Since the tcp-wrapper 19614240Swpaul * package does not ship with FreeBSD, we use the built-in support 19715426Swpaul * by default. Users can recompile the server with the tcp-wrapper library 19814240Swpaul * if they already have it installed and want to use hosts.allow and 19915426Swpaul * hosts.deny to control access instead of having a seperate securenets 20014240Swpaul * file.) 20112891Swpaul * 20214240Swpaul * If no /var/yp/securenets file is present, the host access checks 20314240Swpaul * are bypassed and all hosts are allowed to connect. 20414240Swpaul * 20515426Swpaul * The yp_validdomain() function checks the domain specified by the caller 20612891Swpaul * to make sure it's actually served by this server. This is more a sanity 20712891Swpaul * check than an a security check, but this seems to be the best place for 20812891Swpaul * it. 20912891Swpaul */ 21012891Swpaul 21119161Swpaul#ifdef DB_CACHE 21219161Swpaulint yp_access(map, domain, rqstp) 21319161Swpaul#else 21412891Swpaulint yp_access(map, rqstp) 21519161Swpaul#endif 21612891Swpaul const char *map; 21719161Swpaul#ifdef DB_CACHE 21819161Swpaul const char *domain; 21919161Swpaul#endif 22012891Swpaul const struct svc_req *rqstp; 22112891Swpaul{ 22212891Swpaul struct sockaddr_in *rqhost; 22312891Swpaul int status = 0; 22416044Swpaul static unsigned long oldaddr = 0; 22514240Swpaul#ifndef TCP_WRAPPER 22614240Swpaul struct securenet *tmp; 22712891Swpaul#endif 22814262Swpaul char *yp_procedure = NULL; 22916118Swpaul char procbuf[50]; 23012891Swpaul 23116118Swpaul if (rqstp->rq_prog != YPPASSWDPROG && rqstp->rq_prog != YPPROG) { 23216118Swpaul snprintf(procbuf, sizeof(procbuf), "#%lu/#%lu", rqstp->rq_prog, 23316118Swpaul rqstp->rq_proc); 23416118Swpaul yp_procedure = (char *)&procbuf; 23516118Swpaul } else { 23616118Swpaul yp_procedure = rqstp->rq_prog == YPPASSWDPROG ? 23716118Swpaul "yppasswdprog_update" : 23816118Swpaul yp_procs[rqstp->rq_proc + (12 * (rqstp->rq_vers - 1))]; 23916118Swpaul } 24014262Swpaul 24112891Swpaul rqhost = svc_getcaller(rqstp->rq_xprt); 24212891Swpaul 24312891Swpaul if (debug) { 24414262Swpaul yp_error("Procedure %s called from %s:%d", yp_procedure, 24514262Swpaul inet_ntoa(rqhost->sin_addr), 24612891Swpaul ntohs(rqhost->sin_port)); 24712891Swpaul if (map != NULL) 24812891Swpaul yp_error("Client is referencing map \"%s\".", map); 24912891Swpaul } 25012891Swpaul 25112891Swpaul /* Check the map name if one was supplied. */ 25212891Swpaul if (map != NULL) { 25318586Swpaul if (strchr(map, '/')) { 25418586Swpaul yp_error("embedded slash in map name \"%s\" -- \ 25518586Swpaulpossible spoof attempt from %s:%d", 25618586Swpaul map, inet_ntoa(rqhost->sin_addr), 25718586Swpaul ntohs(rqhost->sin_port)); 25821366Swpaul return(1); 25918586Swpaul } 26019161Swpaul#ifdef DB_CACHE 26119161Swpaul if ((yp_testflag((char *)map, (char *)domain, YP_SECURE) || 26219161Swpaul#else 26314240Swpaul if ((strstr(map, "master.passwd.") || 26419161Swpaul#endif 26518586Swpaul (rqstp->rq_prog == YPPROG && 26618586Swpaul rqstp->rq_proc == YPPROC_XFR) || 26718586Swpaul (rqstp->rq_prog == YPXFRD_FREEBSD_PROG && 26818586Swpaul rqstp->rq_proc == YPXFRD_GETMAP)) && 26918586Swpaul ntohs(rqhost->sin_port) >= IPPORT_RESERVED) { 27018586Swpaul yp_error("Access to %s denied -- client %s:%d \ 27118586Swpaulnot privileged", map, inet_ntoa(rqhost->sin_addr), ntohs(rqhost->sin_port)); 27212891Swpaul return(1); 27312891Swpaul } 27412891Swpaul } 27512891Swpaul 27612891Swpaul#ifdef TCP_WRAPPER 27712891Swpaul status = hosts_ctl(progname, STRING_UNKNOWN, 27814240Swpaul inet_ntoa(rqhost->sin_addr), ""); 27914240Swpaul#else 28014240Swpaul tmp = securenets; 28114240Swpaul while(tmp) { 28214240Swpaul if (((rqhost->sin_addr.s_addr & ~tmp->mask.s_addr) 28314240Swpaul | tmp->net.s_addr) == rqhost->sin_addr.s_addr) { 28414240Swpaul status = 1; 28514240Swpaul break; 28614240Swpaul } 28714240Swpaul tmp = tmp->next; 28814240Swpaul } 28914240Swpaul#endif 29012891Swpaul 29114240Swpaul if (!status) { 29214240Swpaul if (rqhost->sin_addr.s_addr != oldaddr) { 29314240Swpaul yp_error("connect from %s:%d to procedure %s refused", 29414240Swpaul inet_ntoa(rqhost->sin_addr), 29514240Swpaul ntohs(rqhost->sin_port), 29614262Swpaul yp_procedure); 29714240Swpaul oldaddr = rqhost->sin_addr.s_addr; 29814240Swpaul } 29912891Swpaul return(1); 30012891Swpaul } 30112891Swpaul return(0); 30212891Swpaul 30312891Swpaul} 30412891Swpaul 30512891Swpaulint yp_validdomain(domain) 30612891Swpaul const char *domain; 30712891Swpaul{ 30812891Swpaul struct stat statbuf; 30912891Swpaul char dompath[MAXPATHLEN + 2]; 31012891Swpaul 31112891Swpaul if (domain == NULL || strstr(domain, "binding") || 31212891Swpaul !strcmp(domain, ".") || !strcmp(domain, "..") || 31314240Swpaul strchr(domain, '/') || strlen(domain) > YPMAXDOMAIN) 31412891Swpaul return(1); 31512891Swpaul 31612891Swpaul snprintf(dompath, sizeof(dompath), "%s/%s", yp_dir, domain); 31712891Swpaul 31812891Swpaul if (stat(dompath, &statbuf) < 0 || !S_ISDIR(statbuf.st_mode)) 31912891Swpaul return(1); 32012891Swpaul 32115426Swpaul 32212891Swpaul return(0); 32312891Swpaul} 324