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 * $FreeBSD: src/usr.sbin/ypserv/yp_access.c,v 1.23 2006/05/31 22:31:08 cperciva Exp $ 33 * $DragonFly: src/usr.sbin/ypserv/yp_access.c,v 1.5 2006/06/13 12:38:37 corecode Exp $ 34 */ 35 36 #include <stdlib.h> 37 #include <rpc/rpc.h> 38 #include <rpcsvc/yp.h> 39 #include <rpcsvc/yppasswd.h> 40 #include <rpcsvc/ypxfrd.h> 41 #include <sys/types.h> 42 #include <limits.h> 43 #include <db.h> 44 #include <sys/socket.h> 45 #include <netinet/in.h> 46 #include <arpa/inet.h> 47 #include <sys/stat.h> 48 #include <sys/fcntl.h> 49 #include <paths.h> 50 #include <errno.h> 51 #include <sys/param.h> 52 #include "yp_extern.h" 53 #ifdef TCP_WRAPPER 54 #include "tcpd.h" 55 #endif 56 57 extern int debug; 58 59 /* NIS v1 */ 60 const char *yp_procs[] = { 61 "ypoldproc_null", 62 "ypoldproc_domain", 63 "ypoldproc_domain_nonack", 64 "ypoldproc_match", 65 "ypoldproc_first", 66 "ypoldproc_next", 67 "ypoldproc_poll", 68 "ypoldproc_push", 69 "ypoldproc_get", 70 "badproc1", /* placeholder */ 71 "badproc2", /* placeholder */ 72 "badproc3", /* placeholder */ 73 74 /* NIS v2 */ 75 "ypproc_null", 76 "ypproc_domain", 77 "ypproc_domain_nonack", 78 "ypproc_match", 79 "ypproc_first", 80 "ypproc_next", 81 "ypproc_xfr", 82 "ypproc_clear", 83 "ypproc_all", 84 "ypproc_master", 85 "ypproc_order", 86 "ypproc_maplist" 87 }; 88 89 struct securenet { 90 struct in_addr net; 91 struct in_addr mask; 92 struct securenet *next; 93 }; 94 95 struct securenet *securenets; 96 97 #define LINEBUFSZ 1024 98 99 /* 100 * Read /var/yp/securenets file and initialize the securenets 101 * list. If the file doesn't exist, we set up a dummy entry that 102 * allows all hosts to connect. 103 */ 104 void 105 load_securenets(void) 106 { 107 FILE *fp; 108 char path[MAXPATHLEN + 2]; 109 char linebuf[1024 + 2]; 110 struct securenet *tmp; 111 112 /* 113 * If securenets is not NULL, we are being called to reload 114 * the list; free the existing list before re-reading the 115 * securenets file. 116 */ 117 while (securenets) { 118 tmp = securenets->next; 119 free(securenets); 120 securenets = tmp; 121 } 122 123 snprintf(path, MAXPATHLEN, "%s/securenets", yp_dir); 124 125 if ((fp = fopen(path, "r")) == NULL) { 126 if (errno == ENOENT) { 127 securenets = (struct securenet *)malloc(sizeof(struct securenet)); 128 securenets->net.s_addr = INADDR_ANY; 129 securenets->mask.s_addr = INADDR_ANY; 130 securenets->next = NULL; 131 return; 132 } else { 133 yp_error("fopen(%s) failed: %s", path, strerror(errno)); 134 exit(1); 135 } 136 } 137 138 securenets = NULL; 139 140 while (fgets(linebuf, LINEBUFSZ, fp)) { 141 char addr1[20], addr2[20]; 142 143 if ((linebuf[0] == '#') 144 || (strspn(linebuf, " \t\r\n") == strlen(linebuf))) 145 continue; 146 if (sscanf(linebuf, "%s %s", addr1, addr2) < 2) { 147 yp_error("badly formatted securenets entry: %s", 148 linebuf); 149 continue; 150 } 151 152 tmp = (struct securenet *)malloc(sizeof(struct securenet)); 153 154 if (!inet_aton((char *)&addr1, (struct in_addr *)&tmp->net)) { 155 yp_error("badly formatted securenets entry: %s", addr1); 156 free(tmp); 157 continue; 158 } 159 160 if (!inet_aton((char *)&addr2, (struct in_addr *)&tmp->mask)) { 161 yp_error("badly formatted securenets entry: %s", addr2); 162 free(tmp); 163 continue; 164 } 165 166 tmp->next = securenets; 167 securenets = tmp; 168 } 169 170 fclose(fp); 171 172 } 173 174 /* 175 * Access control functions. 176 * 177 * yp_access() checks the mapname and client host address and watches for 178 * the following things: 179 * 180 * - If the client is referencing one of the master.passwd.* maps, it must 181 * be using a privileged port to make its RPC to us. If it is, then we can 182 * assume that the caller is root and allow the RPC to succeed. If it 183 * isn't access is denied. 184 * 185 * - The client's IP address is checked against the securenets rules. 186 * There are two kinds of securenets support: the built-in support, 187 * which is very simple and depends on the presence of a 188 * /var/yp/securenets file, and tcp-wrapper support, which requires 189 * Wietse Venema's libwrap.a and tcpd.h. (Since the tcp-wrapper 190 * package does not ship with FreeBSD, we use the built-in support 191 * by default. Users can recompile the server with the tcp-wrapper library 192 * if they already have it installed and want to use hosts.allow and 193 * hosts.deny to control access instead of having a separate securenets 194 * file.) 195 * 196 * If no /var/yp/securenets file is present, the host access checks 197 * are bypassed and all hosts are allowed to connect. 198 * 199 * The yp_validdomain() function checks the domain specified by the caller 200 * to make sure it's actually served by this server. This is more a sanity 201 * check than an a security check, but this seems to be the best place for 202 * it. 203 */ 204 205 #ifdef DB_CACHE 206 int 207 yp_access(const char *map, const char *domain, const struct svc_req *rqstp) 208 #else 209 int 210 yp_access(const char *map, const struct svc_req *rqstp) 211 #endif 212 { 213 struct sockaddr_in *rqhost; 214 int status_securenets = 0; 215 #ifdef TCP_WRAPPER 216 int status_tcpwrap; 217 #endif 218 static unsigned long oldaddr = 0; 219 struct securenet *tmp; 220 const char *yp_procedure = NULL; 221 char procbuf[50]; 222 223 if (rqstp->rq_prog != YPPASSWDPROG && rqstp->rq_prog != YPPROG) { 224 snprintf(procbuf, sizeof(procbuf), "#%lu/#%lu", 225 (unsigned long)rqstp->rq_prog, 226 (unsigned long)rqstp->rq_proc); 227 yp_procedure = (char *)&procbuf; 228 } else { 229 yp_procedure = rqstp->rq_prog == YPPASSWDPROG ? 230 "yppasswdprog_update" : 231 yp_procs[rqstp->rq_proc + (12 * (rqstp->rq_vers - 1))]; 232 } 233 234 rqhost = svc_getcaller(rqstp->rq_xprt); 235 236 if (debug) { 237 yp_error("procedure %s called from %s:%d", yp_procedure, 238 inet_ntoa(rqhost->sin_addr), 239 ntohs(rqhost->sin_port)); 240 if (map != NULL) 241 yp_error("client is referencing map \"%s\".", map); 242 } 243 244 /* Check the map name if one was supplied. */ 245 if (map != NULL) { 246 if (strchr(map, '/')) { 247 yp_error("embedded slash in map name \"%s\" -- \ 248 possible spoof attempt from %s:%d", 249 map, inet_ntoa(rqhost->sin_addr), 250 ntohs(rqhost->sin_port)); 251 return(1); 252 } 253 #ifdef DB_CACHE 254 if ((yp_testflag((char *)map, (char *)domain, YP_SECURE) || 255 #else 256 if ((strstr(map, "master.passwd.") || 257 #endif 258 (rqstp->rq_prog == YPPROG && 259 rqstp->rq_proc == YPPROC_XFR) || 260 (rqstp->rq_prog == YPXFRD_FREEBSD_PROG && 261 rqstp->rq_proc == YPXFRD_GETMAP)) && 262 ntohs(rqhost->sin_port) >= IPPORT_RESERVED) { 263 yp_error("access to %s denied -- client %s:%d \ 264 not privileged", map, inet_ntoa(rqhost->sin_addr), ntohs(rqhost->sin_port)); 265 return(1); 266 } 267 } 268 269 #ifdef TCP_WRAPPER 270 status_tcpwrap = hosts_ctl("ypserv", STRING_UNKNOWN, 271 inet_ntoa(rqhost->sin_addr), ""); 272 #endif 273 tmp = securenets; 274 while (tmp) { 275 if (((rqhost->sin_addr.s_addr & ~tmp->mask.s_addr) 276 | tmp->net.s_addr) == rqhost->sin_addr.s_addr) { 277 status_securenets = 1; 278 break; 279 } 280 tmp = tmp->next; 281 } 282 283 #ifdef TCP_WRAPPER 284 if (status_securenets == 0 || status_tcpwrap == 0) { 285 #else 286 if (status_securenets == 0) { 287 #endif 288 /* 289 * One of the following two events occured: 290 * 291 * (1) The /var/yp/securenets exists and the remote host does not 292 * match any of the networks specified in it. 293 * (2) The hosts.allow file has denied access and TCP_WRAPPER is 294 * defined. 295 * 296 * In either case deny access. 297 */ 298 if (rqhost->sin_addr.s_addr != oldaddr) { 299 yp_error("connect from %s:%d to procedure %s refused", 300 inet_ntoa(rqhost->sin_addr), 301 ntohs(rqhost->sin_port), 302 yp_procedure); 303 oldaddr = rqhost->sin_addr.s_addr; 304 } 305 return(1); 306 } 307 return(0); 308 309 } 310 311 int 312 yp_validdomain(const char *domain) 313 { 314 struct stat statbuf; 315 char dompath[MAXPATHLEN + 2]; 316 317 if (domain == NULL || strstr(domain, "binding") || 318 !strcmp(domain, ".") || !strcmp(domain, "..") || 319 strchr(domain, '/') || strlen(domain) > YPMAXDOMAIN) 320 return(1); 321 322 snprintf(dompath, sizeof(dompath), "%s/%s", yp_dir, domain); 323 324 if (stat(dompath, &statbuf) < 0 || !S_ISDIR(statbuf.st_mode)) 325 return(1); 326 327 328 return(0); 329 } 330