1 /* 2 * Copyright (c) 1995 3 * Bill Paul <wpaul@ctr.columbia.edu>. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by Bill Paul. 16 * 4. Neither the name of the author nor the names of any co-contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY Bill Paul AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL Bill Paul OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 */ 33 34 #include <stdlib.h> 35 #include <rpc/rpc.h> 36 #include <rpcsvc/yp.h> 37 #include <rpcsvc/yppasswd.h> 38 #include <rpcsvc/ypxfrd.h> 39 #include <sys/types.h> 40 #include <limits.h> 41 #include <db.h> 42 #include <sys/socket.h> 43 #include <netinet/in.h> 44 #include <arpa/inet.h> 45 #include <sys/stat.h> 46 #include <sys/fcntl.h> 47 #include <paths.h> 48 #include <errno.h> 49 #include <sys/param.h> 50 #include "yp_extern.h" 51 #ifdef TCP_WRAPPER 52 #include "tcpd.h" 53 #endif 54 55 #ifndef lint 56 static const char rcsid[] = "$Id$"; 57 #endif 58 59 extern int debug; 60 61 /* NIS v1 */ 62 char *yp_procs[] = { "ypoldproc_null", 63 "ypoldproc_domain", 64 "ypoldproc_domain_nonack", 65 "ypoldproc_match", 66 "ypoldproc_first", 67 "ypoldproc_next", 68 "ypoldproc_poll", 69 "ypoldproc_push", 70 "ypoldproc_get", 71 "badproc1", /* placeholder */ 72 "badproc2", /* placeholder */ 73 "badproc3", /* placeholder */ 74 75 /* NIS v2 */ 76 "ypproc_null" , 77 "ypproc_domain", 78 "ypproc_domain_nonack", 79 "ypproc_match", 80 "ypproc_first", 81 "ypproc_next", 82 "ypproc_xfr", 83 "ypproc_clear", 84 "ypproc_all", 85 "ypproc_master", 86 "ypproc_order", 87 "ypproc_maplist" 88 }; 89 90 91 #ifdef TCP_WRAPPER 92 void load_securenets() 93 { 94 } 95 #else 96 struct securenet { 97 struct in_addr net; 98 struct in_addr mask; 99 struct securenet *next; 100 }; 101 102 struct securenet *securenets; 103 104 #define LINEBUFSZ 1024 105 106 /* 107 * Read /var/yp/securenets file and initialize the securenets 108 * list. If the file doesn't exist, we set up a dummy entry that 109 * allows all hosts to connect. 110 */ 111 void load_securenets() 112 { 113 FILE *fp; 114 char path[MAXPATHLEN + 2]; 115 char linebuf[1024 + 2]; 116 struct securenet *tmp; 117 118 /* 119 * If securenets is not NULL, we are being called to reload 120 * the list; free the existing list before re-reading the 121 * securenets file. 122 */ 123 while(securenets) { 124 tmp = securenets->next; 125 free(securenets); 126 securenets = tmp; 127 } 128 129 snprintf(path, MAXPATHLEN, "%s/securenets", yp_dir); 130 131 if ((fp = fopen(path, "r")) == NULL) { 132 if (errno == ENOENT) { 133 securenets = (struct securenet *)malloc(sizeof(struct securenet)); 134 securenets->net.s_addr = INADDR_ANY; 135 securenets->mask.s_addr = INADDR_ANY; 136 securenets->next = NULL; 137 return; 138 } else { 139 yp_error("fopen(%s) failed: %s", path, strerror(errno)); 140 exit(1); 141 } 142 } 143 144 securenets = NULL; 145 146 while(fgets(linebuf, LINEBUFSZ, fp)) { 147 char addr1[20], addr2[20]; 148 149 if (linebuf[0] == '#') 150 continue; 151 if (sscanf(linebuf, "%s %s", addr1, addr2) < 2) { 152 yp_error("badly formatted securenets entry: %s", 153 linebuf); 154 continue; 155 } 156 157 tmp = (struct securenet *)malloc(sizeof(struct securenet)); 158 159 if (!inet_aton((char *)&addr1, (struct in_addr *)&tmp->net)) { 160 yp_error("badly formatted securenets entry: %s", addr1); 161 free(tmp); 162 continue; 163 } 164 165 if (!inet_aton((char *)&addr2, (struct in_addr *)&tmp->mask)) { 166 yp_error("badly formatted securenets entry: %s", addr2); 167 free(tmp); 168 continue; 169 } 170 171 tmp->next = securenets; 172 securenets = tmp; 173 } 174 175 fclose(fp); 176 177 } 178 #endif 179 180 /* 181 * Access control functions. 182 * 183 * yp_access() checks the mapname and client host address and watches for 184 * the following things: 185 * 186 * - If the client is referencing one of the master.passwd.* maps, it must 187 * be using a privileged port to make its RPC to us. If it is, then we can 188 * assume that the caller is root and allow the RPC to succeed. If it 189 * isn't access is denied. 190 * 191 * - The client's IP address is checked against the securenets rules. 192 * There are two kinds of securenets support: the built-in support, 193 * which is very simple and depends on the presence of a 194 * /var/yp/securenets file, and tcp-wrapper support, which requires 195 * Wietse Venema's libwrap.a and tcpd.h. (Since the tcp-wrapper 196 * package does not ship with FreeBSD, we use the built-in support 197 * by default. Users can recompile the server with the tcp-wrapper library 198 * if they already have it installed and want to use hosts.allow and 199 * hosts.deny to control access instead of having a seperate securenets 200 * file.) 201 * 202 * If no /var/yp/securenets file is present, the host access checks 203 * are bypassed and all hosts are allowed to connect. 204 * 205 * The yp_validdomain() function checks the domain specified by the caller 206 * to make sure it's actually served by this server. This is more a sanity 207 * check than an a security check, but this seems to be the best place for 208 * it. 209 */ 210 211 #ifdef DB_CACHE 212 int yp_access(map, domain, rqstp) 213 #else 214 int yp_access(map, rqstp) 215 #endif 216 const char *map; 217 #ifdef DB_CACHE 218 const char *domain; 219 #endif 220 const struct svc_req *rqstp; 221 { 222 struct sockaddr_in *rqhost; 223 int status = 0; 224 static unsigned long oldaddr = 0; 225 #ifndef TCP_WRAPPER 226 struct securenet *tmp; 227 #endif 228 char *yp_procedure = NULL; 229 char procbuf[50]; 230 231 if (rqstp->rq_prog != YPPASSWDPROG && rqstp->rq_prog != YPPROG) { 232 snprintf(procbuf, sizeof(procbuf), "#%lu/#%lu", rqstp->rq_prog, 233 rqstp->rq_proc); 234 yp_procedure = (char *)&procbuf; 235 } else { 236 yp_procedure = rqstp->rq_prog == YPPASSWDPROG ? 237 "yppasswdprog_update" : 238 yp_procs[rqstp->rq_proc + (12 * (rqstp->rq_vers - 1))]; 239 } 240 241 rqhost = svc_getcaller(rqstp->rq_xprt); 242 243 if (debug) { 244 yp_error("Procedure %s called from %s:%d", yp_procedure, 245 inet_ntoa(rqhost->sin_addr), 246 ntohs(rqhost->sin_port)); 247 if (map != NULL) 248 yp_error("Client is referencing map \"%s\".", map); 249 } 250 251 /* Check the map name if one was supplied. */ 252 if (map != NULL) { 253 if (strchr(map, '/')) { 254 yp_error("embedded slash in map name \"%s\" -- \ 255 possible spoof attempt from %s:%d", 256 map, inet_ntoa(rqhost->sin_addr), 257 ntohs(rqhost->sin_port)); 258 return(1); 259 } 260 #ifdef DB_CACHE 261 if ((yp_testflag((char *)map, (char *)domain, YP_SECURE) || 262 #else 263 if ((strstr(map, "master.passwd.") || 264 #endif 265 (rqstp->rq_prog == YPPROG && 266 rqstp->rq_proc == YPPROC_XFR) || 267 (rqstp->rq_prog == YPXFRD_FREEBSD_PROG && 268 rqstp->rq_proc == YPXFRD_GETMAP)) && 269 ntohs(rqhost->sin_port) >= IPPORT_RESERVED) { 270 yp_error("Access to %s denied -- client %s:%d \ 271 not privileged", map, inet_ntoa(rqhost->sin_addr), ntohs(rqhost->sin_port)); 272 return(1); 273 } 274 } 275 276 #ifdef TCP_WRAPPER 277 status = hosts_ctl(progname, STRING_UNKNOWN, 278 inet_ntoa(rqhost->sin_addr), ""); 279 #else 280 tmp = securenets; 281 while(tmp) { 282 if (((rqhost->sin_addr.s_addr & ~tmp->mask.s_addr) 283 | tmp->net.s_addr) == rqhost->sin_addr.s_addr) { 284 status = 1; 285 break; 286 } 287 tmp = tmp->next; 288 } 289 #endif 290 291 if (!status) { 292 if (rqhost->sin_addr.s_addr != oldaddr) { 293 yp_error("connect from %s:%d to procedure %s refused", 294 inet_ntoa(rqhost->sin_addr), 295 ntohs(rqhost->sin_port), 296 yp_procedure); 297 oldaddr = rqhost->sin_addr.s_addr; 298 } 299 return(1); 300 } 301 return(0); 302 303 } 304 305 int yp_validdomain(domain) 306 const char *domain; 307 { 308 struct stat statbuf; 309 char dompath[MAXPATHLEN + 2]; 310 311 if (domain == NULL || strstr(domain, "binding") || 312 !strcmp(domain, ".") || !strcmp(domain, "..") || 313 strchr(domain, '/') || strlen(domain) > YPMAXDOMAIN) 314 return(1); 315 316 snprintf(dompath, sizeof(dompath), "%s/%s", yp_dir, domain); 317 318 if (stat(dompath, &statbuf) < 0 || !S_ISDIR(statbuf.st_mode)) 319 return(1); 320 321 322 return(0); 323 } 324