yp_access.c revision 14302
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> 3812891Swpaul#include <sys/types.h> 3912891Swpaul#include <sys/socket.h> 4012891Swpaul#include <netinet/in.h> 4112891Swpaul#include <arpa/inet.h> 4212891Swpaul#include <sys/stat.h> 4312891Swpaul#include <paths.h> 4414240Swpaul#include <errno.h> 4512891Swpaul#include <sys/param.h> 4612891Swpaul#include "yp_extern.h" 4712891Swpaul#ifdef TCP_WRAPPER 4812891Swpaul#include "tcpd.h" 4912891Swpaul#endif 5012891Swpaul 5114240Swpaul#ifndef lint 5214302Sadamstatic const char rcsid[] = "$Id: yp_access.c,v 1.5 1996/02/26 02:34:23 wpaul Exp $"; 5314240Swpaul#endif 5414240Swpaul 5512891Swpaulextern int debug; 5612891Swpaul 5714262Swpaul /* NIS v1 */ 5814262Swpaulchar *yp_procs[] = { "ypoldproc_null", 5914262Swpaul "ypoldproc_domain", 6014262Swpaul "ypoldproc_domain_nonack", 6114262Swpaul "ypoldproc_match", 6214262Swpaul "ypoldproc_first", 6314262Swpaul "ypoldproc_next", 6414262Swpaul "ypoldproc_poll", 6514262Swpaul "ypoldproc_push", 6614262Swpaul "ypoldproc_get", 6714262Swpaul "badproc1", /* placeholder */ 6814262Swpaul "badproc2", /* placeholder */ 6914262Swpaul "badproc3", /* placeholder */ 7014262Swpaul 7114262Swpaul /* NIS v2 */ 7214262Swpaul "ypproc_null" , 7312891Swpaul "ypproc_domain", 7412891Swpaul "ypproc_domain_nonack", 7512891Swpaul "ypproc_match", 7612891Swpaul "ypproc_first", 7712891Swpaul "ypproc_next", 7812891Swpaul "ypproc_xfr", 7912891Swpaul "ypproc_clear", 8012891Swpaul "ypproc_all", 8112891Swpaul "ypproc_master", 8212891Swpaul "ypproc_order", 8312891Swpaul "ypproc_maplist" 8412891Swpaul }; 8512891Swpaul 8614262Swpaul 8714240Swpaul#ifdef TCP_WRAPPER 8814240Swpaulvoid load_securenets() 8914240Swpaul{ 9014240Swpaul} 9114240Swpaul#else 9214240Swpaulstruct securenet { 9314240Swpaul struct in_addr net; 9414240Swpaul struct in_addr mask; 9514240Swpaul struct securenet *next; 9614240Swpaul}; 9714240Swpaul 9814240Swpaulstruct securenet *securenets; 9914240Swpaul 10014240Swpaul#define LINEBUFSZ 1024 10114240Swpaul 10212891Swpaul/* 10314240Swpaul * Read /var/yp/securenets file and initialize the securenets 10414240Swpaul * list. If the file doesn't exist, we set up a dummy entry that 10514240Swpaul * allows all hosts to connect. 10614240Swpaul */ 10714240Swpaulvoid load_securenets() 10814240Swpaul{ 10914240Swpaul FILE *fp; 11014240Swpaul char path[MAXPATHLEN + 2]; 11114240Swpaul char linebuf[1024 + 2]; 11214240Swpaul struct securenet *tmp; 11314240Swpaul 11414240Swpaul /* 11514240Swpaul * If securenets is not NULL, we are being called to reload 11614240Swpaul * the list; free the existing list before re-reading the 11714240Swpaul * securenets file. 11814240Swpaul */ 11914240Swpaul if (securenets != NULL) { 12014240Swpaul while(securenets) { 12114240Swpaul tmp = securenets->next; 12214240Swpaul free(securenets); 12314240Swpaul securenets = tmp; 12414240Swpaul } 12514240Swpaul } 12614240Swpaul 12714240Swpaul snprintf(path, MAXPATHLEN, "%s/securenets", yp_dir); 12814240Swpaul 12914240Swpaul if ((fp = fopen(path, "r")) == NULL) { 13014240Swpaul if (errno == ENOENT) { 13114240Swpaul securenets = (struct securenet *)malloc(sizeof(struct securenet)); 13214240Swpaul securenets->net.s_addr = INADDR_ANY; 13314302Sadam securenets->mask.s_addr = INADDR_ANY; 13414240Swpaul securenets->next = NULL; 13514240Swpaul return; 13614240Swpaul } else { 13714240Swpaul yp_error("fopen(%s) failed: %s", path, strerror(errno)); 13814240Swpaul exit(1); 13914240Swpaul } 14014240Swpaul } 14114240Swpaul 14214240Swpaul securenets = NULL; 14314240Swpaul 14414240Swpaul while(fgets(linebuf, LINEBUFSZ, fp)) { 14514240Swpaul char addr1[20], addr2[20]; 14614240Swpaul 14714240Swpaul if (linebuf[0] == '#') 14814240Swpaul continue; 14914240Swpaul if (sscanf(linebuf, "%s %s", addr1, addr2) < 2) { 15014240Swpaul yp_error("badly formatted securenets entry: %s", 15114240Swpaul linebuf); 15214240Swpaul continue; 15314240Swpaul } 15414240Swpaul 15514240Swpaul tmp = (struct securenet *)malloc(sizeof(struct securenet)); 15614240Swpaul 15714240Swpaul if (!inet_aton((char *)&addr1, (struct in_addr *)&tmp->net)) { 15814240Swpaul yp_error("badly formatted securenets entry: %s", addr1); 15914240Swpaul free(tmp); 16014240Swpaul continue; 16114240Swpaul } 16214240Swpaul 16314240Swpaul if (!inet_aton((char *)&addr2, (struct in_addr *)&tmp->mask)) { 16414240Swpaul yp_error("badly formatted securenets entry: %s", addr2); 16514240Swpaul free(tmp); 16614240Swpaul continue; 16714240Swpaul } 16814240Swpaul 16914240Swpaul tmp->next = securenets; 17014240Swpaul securenets = tmp; 17114240Swpaul } 17214240Swpaul 17314240Swpaul fclose(fp); 17414240Swpaul 17514240Swpaul} 17614240Swpaul#endif 17714240Swpaul 17814240Swpaul/* 17912891Swpaul * Access control functions. 18012891Swpaul * 18112891Swpaul * yp_access() checks the mapname and client host address and watches for 18212891Swpaul * the following things: 18312891Swpaul * 18412891Swpaul * - If the client is referencing one of the master.passwd.* maps, it must 18512891Swpaul * be using a privileged port to make its RPC to us. If it is, then we can 18612891Swpaul * assume that the caller is root and allow the RPC to succeed. If it 18712891Swpaul * isn't access is denied. 18812891Swpaul * 18914240Swpaul * - The client's IP address is checked against the securenets rules. 19014240Swpaul * There are two kinds of securenets support: the built-in support, 19114240Swpaul * which is very simple and depends on the presense of a 19214240Swpaul * /var/yp/securenets file, and tcp-wrapper support, which requires 19314240Swpaul * Wietse Venema's libwrap.a and tcpd.h. (Since the tcp-wrapper 19414240Swpaul * package does not ship with FreeBSD, we use the built-in support 19514240Swpaul * by default. Users can recompile the server the tcp-wrapper library 19614240Swpaul * if they already have it installed and want to use hosts.allow and 19714240Swpaul * hosts.deny to control access instead od having a seperate securenets 19814240Swpaul * file.) 19912891Swpaul * 20014240Swpaul * If no /var/yp/securenets file is present, the host access checks 20114240Swpaul * are bypassed and all hosts are allowed to connect. 20214240Swpaul * 20312891Swpaul * The yp_validdomain() functions checks the domain specified by the caller 20412891Swpaul * to make sure it's actually served by this server. This is more a sanity 20512891Swpaul * check than an a security check, but this seems to be the best place for 20612891Swpaul * it. 20712891Swpaul */ 20812891Swpaul 20912891Swpaulint yp_access(map, rqstp) 21012891Swpaul const char *map; 21112891Swpaul const struct svc_req *rqstp; 21212891Swpaul{ 21312891Swpaul struct sockaddr_in *rqhost; 21412891Swpaul int status = 0; 21512891Swpaul unsigned long oldaddr; 21614240Swpaul#ifndef TCP_WRAPPER 21714240Swpaul struct securenet *tmp; 21812891Swpaul#endif 21914262Swpaul char *yp_procedure = NULL; 22012891Swpaul 22114262Swpaul yp_procedure = rqstp->rq_prog == YPPASSWDPROG ? "yppasswdprog_update" : 22214262Swpaul yp_procs[rqstp->rq_proc + (12 * (rqstp->rq_vers - 1))]; 22314262Swpaul 22412891Swpaul rqhost = svc_getcaller(rqstp->rq_xprt); 22512891Swpaul 22612891Swpaul if (debug) { 22714262Swpaul yp_error("Procedure %s called from %s:%d", yp_procedure, 22814262Swpaul inet_ntoa(rqhost->sin_addr), 22912891Swpaul ntohs(rqhost->sin_port)); 23012891Swpaul if (map != NULL) 23112891Swpaul yp_error("Client is referencing map \"%s\".", map); 23212891Swpaul } 23312891Swpaul 23412891Swpaul /* Check the map name if one was supplied. */ 23512891Swpaul if (map != NULL) { 23614240Swpaul if ((strstr(map, "master.passwd.") || 23714240Swpaul rqstp->rq_proc == YPPROC_XFR) && 23814240Swpaul ntohs(rqhost->sin_port) > 1023) { 23912891Swpaul yp_error("Access to %s denied -- client not privileged", map); 24012891Swpaul return(1); 24112891Swpaul } 24212891Swpaul } 24312891Swpaul 24412891Swpaul#ifdef TCP_WRAPPER 24512891Swpaul status = hosts_ctl(progname, STRING_UNKNOWN, 24614240Swpaul inet_ntoa(rqhost->sin_addr), ""); 24714240Swpaul#else 24814240Swpaul tmp = securenets; 24914240Swpaul while(tmp) { 25014240Swpaul if (((rqhost->sin_addr.s_addr & ~tmp->mask.s_addr) 25114240Swpaul | tmp->net.s_addr) == rqhost->sin_addr.s_addr) { 25214240Swpaul status = 1; 25314240Swpaul break; 25414240Swpaul } 25514240Swpaul tmp = tmp->next; 25614240Swpaul } 25714240Swpaul#endif 25812891Swpaul 25914240Swpaul if (!status) { 26014240Swpaul if (rqhost->sin_addr.s_addr != oldaddr) { 26114240Swpaul yp_error("connect from %s:%d to procedure %s refused", 26214240Swpaul inet_ntoa(rqhost->sin_addr), 26314240Swpaul ntohs(rqhost->sin_port), 26414262Swpaul yp_procedure); 26514240Swpaul oldaddr = rqhost->sin_addr.s_addr; 26614240Swpaul } 26712891Swpaul return(1); 26812891Swpaul } 26912891Swpaul return(0); 27012891Swpaul 27112891Swpaul} 27212891Swpaul 27312891Swpaulint yp_validdomain(domain) 27412891Swpaul const char *domain; 27512891Swpaul{ 27612891Swpaul struct stat statbuf; 27712891Swpaul char dompath[MAXPATHLEN + 2]; 27812891Swpaul 27912891Swpaul if (domain == NULL || strstr(domain, "binding") || 28012891Swpaul !strcmp(domain, ".") || !strcmp(domain, "..") || 28114240Swpaul strchr(domain, '/') || strlen(domain) > YPMAXDOMAIN) 28212891Swpaul return(1); 28312891Swpaul 28412891Swpaul snprintf(dompath, sizeof(dompath), "%s/%s", yp_dir, domain); 28512891Swpaul 28612891Swpaul if (stat(dompath, &statbuf) < 0 || !S_ISDIR(statbuf.st_mode)) 28712891Swpaul return(1); 28812891Swpaul 28912891Swpaul return(0); 29012891Swpaul} 291