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 1.17.2.1 2002/02/15 00:47:00 des 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 char *yp_procs[] = { "ypoldproc_null", 61 "ypoldproc_domain", 62 "ypoldproc_domain_nonack", 63 "ypoldproc_match", 64 "ypoldproc_first", 65 "ypoldproc_next", 66 "ypoldproc_poll", 67 "ypoldproc_push", 68 "ypoldproc_get", 69 "badproc1", /* placeholder */ 70 "badproc2", /* placeholder */ 71 "badproc3", /* placeholder */ 72 73 /* NIS v2 */ 74 "ypproc_null", 75 "ypproc_domain", 76 "ypproc_domain_nonack", 77 "ypproc_match", 78 "ypproc_first", 79 "ypproc_next", 80 "ypproc_xfr", 81 "ypproc_clear", 82 "ypproc_all", 83 "ypproc_master", 84 "ypproc_order", 85 "ypproc_maplist" 86 }; 87 88 struct securenet { 89 struct in_addr net; 90 struct in_addr mask; 91 struct securenet *next; 92 }; 93 94 struct securenet *securenets; 95 96 #define LINEBUFSZ 1024 97 98 /* 99 * Read /var/yp/securenets file and initialize the securenets 100 * list. If the file doesn't exist, we set up a dummy entry that 101 * allows all hosts to connect. 102 */ 103 void 104 load_securenets(void) 105 { 106 FILE *fp; 107 char path[MAXPATHLEN + 2]; 108 char linebuf[1024 + 2]; 109 struct securenet *tmp; 110 111 /* 112 * If securenets is not NULL, we are being called to reload 113 * the list; free the existing list before re-reading the 114 * securenets file. 115 */ 116 while (securenets) { 117 tmp = securenets->next; 118 free(securenets); 119 securenets = tmp; 120 } 121 122 snprintf(path, MAXPATHLEN, "%s/securenets", yp_dir); 123 124 if ((fp = fopen(path, "r")) == NULL) { 125 if (errno == ENOENT) { 126 securenets = (struct securenet *)malloc(sizeof(struct securenet)); 127 securenets->net.s_addr = INADDR_ANY; 128 securenets->mask.s_addr = INADDR_ANY; 129 securenets->next = NULL; 130 return; 131 } else { 132 yp_error("fopen(%s) failed: %s", path, strerror(errno)); 133 exit(1); 134 } 135 } 136 137 securenets = NULL; 138 139 while (fgets(linebuf, LINEBUFSZ, fp)) { 140 char addr1[20], addr2[20]; 141 142 if ((linebuf[0] == '#') 143 || (strspn(linebuf, " \t\r\n") == strlen(linebuf))) 144 continue; 145 if (sscanf(linebuf, "%s %s", addr1, addr2) < 2) { 146 yp_error("badly formatted securenets entry: %s", 147 linebuf); 148 continue; 149 } 150 151 tmp = (struct securenet *)malloc(sizeof(struct securenet)); 152 153 if (!inet_aton((char *)&addr1, (struct in_addr *)&tmp->net)) { 154 yp_error("badly formatted securenets entry: %s", addr1); 155 free(tmp); 156 continue; 157 } 158 159 if (!inet_aton((char *)&addr2, (struct in_addr *)&tmp->mask)) { 160 yp_error("badly formatted securenets entry: %s", addr2); 161 free(tmp); 162 continue; 163 } 164 165 tmp->next = securenets; 166 securenets = tmp; 167 } 168 169 fclose(fp); 170 171 } 172 173 /* 174 * Access control functions. 175 * 176 * yp_access() checks the mapname and client host address and watches for 177 * the following things: 178 * 179 * - If the client is referencing one of the master.passwd.* maps, it must 180 * be using a privileged port to make its RPC to us. If it is, then we can 181 * assume that the caller is root and allow the RPC to succeed. If it 182 * isn't access is denied. 183 * 184 * - The client's IP address is checked against the securenets rules. 185 * There are two kinds of securenets support: the built-in support, 186 * which is very simple and depends on the presence of a 187 * /var/yp/securenets file, and tcp-wrapper support, which requires 188 * Wietse Venema's libwrap.a and tcpd.h. (Since the tcp-wrapper 189 * package does not ship with FreeBSD, we use the built-in support 190 * by default. Users can recompile the server with the tcp-wrapper library 191 * if they already have it installed and want to use hosts.allow and 192 * hosts.deny to control access instead of having a separate securenets 193 * file.) 194 * 195 * If no /var/yp/securenets file is present, the host access checks 196 * are bypassed and all hosts are allowed to connect. 197 * 198 * The yp_validdomain() function checks the domain specified by the caller 199 * to make sure it's actually served by this server. This is more a sanity 200 * check than an a security check, but this seems to be the best place for 201 * it. 202 */ 203 204 #ifdef DB_CACHE 205 int 206 yp_access(const char *map, const char *domain, const struct svc_req *rqstp) 207 #else 208 int 209 yp_access(const char *map, const struct svc_req *rqstp) 210 #endif 211 { 212 struct sockaddr_in *rqhost; 213 int status_securenets = 0; 214 #ifdef TCP_WRAPPER 215 int status_tcpwrap; 216 #endif 217 static unsigned long oldaddr = 0; 218 struct securenet *tmp; 219 char *yp_procedure = NULL; 220 char procbuf[50]; 221 222 if (rqstp->rq_prog != YPPASSWDPROG && rqstp->rq_prog != YPPROG) { 223 snprintf(procbuf, sizeof(procbuf), "#%lu/#%lu", rqstp->rq_prog, 224 rqstp->rq_proc); 225 yp_procedure = (char *)&procbuf; 226 } else { 227 yp_procedure = rqstp->rq_prog == YPPASSWDPROG ? 228 "yppasswdprog_update" : 229 yp_procs[rqstp->rq_proc + (12 * (rqstp->rq_vers - 1))]; 230 } 231 232 rqhost = svc_getcaller(rqstp->rq_xprt); 233 234 if (debug) { 235 yp_error("procedure %s called from %s:%d", yp_procedure, 236 inet_ntoa(rqhost->sin_addr), 237 ntohs(rqhost->sin_port)); 238 if (map != NULL) 239 yp_error("client is referencing map \"%s\".", map); 240 } 241 242 /* Check the map name if one was supplied. */ 243 if (map != NULL) { 244 if (strchr(map, '/')) { 245 yp_error("embedded slash in map name \"%s\" -- \ 246 possible spoof attempt from %s:%d", 247 map, inet_ntoa(rqhost->sin_addr), 248 ntohs(rqhost->sin_port)); 249 return(1); 250 } 251 #ifdef DB_CACHE 252 if ((yp_testflag((char *)map, (char *)domain, YP_SECURE) || 253 #else 254 if ((strstr(map, "master.passwd.") || 255 #endif 256 (rqstp->rq_prog == YPPROG && 257 rqstp->rq_proc == YPPROC_XFR) || 258 (rqstp->rq_prog == YPXFRD_FREEBSD_PROG && 259 rqstp->rq_proc == YPXFRD_GETMAP)) && 260 ntohs(rqhost->sin_port) >= IPPORT_RESERVED) { 261 yp_error("access to %s denied -- client %s:%d \ 262 not privileged", map, inet_ntoa(rqhost->sin_addr), ntohs(rqhost->sin_port)); 263 return(1); 264 } 265 } 266 267 #ifdef TCP_WRAPPER 268 status_tcpwrap = hosts_ctl("ypserv", STRING_UNKNOWN, 269 inet_ntoa(rqhost->sin_addr), ""); 270 #endif 271 tmp = securenets; 272 while (tmp) { 273 if (((rqhost->sin_addr.s_addr & ~tmp->mask.s_addr) 274 | tmp->net.s_addr) == rqhost->sin_addr.s_addr) { 275 status_securenets = 1; 276 break; 277 } 278 tmp = tmp->next; 279 } 280 281 #ifdef TCP_WRAPPER 282 if (status_securenets == 0 || status_tcpwrap == 0) { 283 #else 284 if (status_securenets == 0) { 285 #endif 286 /* 287 * One of the following two events occured: 288 * 289 * (1) The /var/yp/securenets exists and the remote host does not 290 * match any of the networks specified in it. 291 * (2) The hosts.allow file has denied access and TCP_WRAPPER is 292 * defined. 293 * 294 * In either case deny access. 295 */ 296 if (rqhost->sin_addr.s_addr != oldaddr) { 297 yp_error("connect from %s:%d to procedure %s refused", 298 inet_ntoa(rqhost->sin_addr), 299 ntohs(rqhost->sin_port), 300 yp_procedure); 301 oldaddr = rqhost->sin_addr.s_addr; 302 } 303 return(1); 304 } 305 return(0); 306 307 } 308 309 int 310 yp_validdomain(const char *domain) 311 { 312 struct stat statbuf; 313 char dompath[MAXPATHLEN + 2]; 314 315 if (domain == NULL || strstr(domain, "binding") || 316 !strcmp(domain, ".") || !strcmp(domain, "..") || 317 strchr(domain, '/') || strlen(domain) > YPMAXDOMAIN) 318 return(1); 319 320 snprintf(dompath, sizeof(dompath), "%s/%s", yp_dir, domain); 321 322 if (stat(dompath, &statbuf) < 0 || !S_ISDIR(statbuf.st_mode)) 323 return(1); 324 325 326 return(0); 327 } 328