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 1.4 2004/03/31 23:20:22 cpressey 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 89 #ifdef TCP_WRAPPER 90 void 91 load_securenets(void) 92 { 93 } 94 #else 95 struct securenet { 96 struct in_addr net; 97 struct in_addr mask; 98 struct securenet *next; 99 }; 100 101 struct securenet *securenets; 102 103 #define LINEBUFSZ 1024 104 105 /* 106 * Read /var/yp/securenets file and initialize the securenets 107 * list. If the file doesn't exist, we set up a dummy entry that 108 * allows all hosts to connect. 109 */ 110 void 111 load_securenets(void) 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 || (strspn(linebuf, " \t\r\n") == strlen(linebuf))) 151 continue; 152 if (sscanf(linebuf, "%s %s", addr1, addr2) < 2) { 153 yp_error("badly formatted securenets entry: %s", 154 linebuf); 155 continue; 156 } 157 158 tmp = (struct securenet *)malloc(sizeof(struct securenet)); 159 160 if (!inet_aton((char *)&addr1, (struct in_addr *)&tmp->net)) { 161 yp_error("badly formatted securenets entry: %s", addr1); 162 free(tmp); 163 continue; 164 } 165 166 if (!inet_aton((char *)&addr2, (struct in_addr *)&tmp->mask)) { 167 yp_error("badly formatted securenets entry: %s", addr2); 168 free(tmp); 169 continue; 170 } 171 172 tmp->next = securenets; 173 securenets = tmp; 174 } 175 176 fclose(fp); 177 178 } 179 #endif 180 181 /* 182 * Access control functions. 183 * 184 * yp_access() checks the mapname and client host address and watches for 185 * the following things: 186 * 187 * - If the client is referencing one of the master.passwd.* maps, it must 188 * be using a privileged port to make its RPC to us. If it is, then we can 189 * assume that the caller is root and allow the RPC to succeed. If it 190 * isn't access is denied. 191 * 192 * - The client's IP address is checked against the securenets rules. 193 * There are two kinds of securenets support: the built-in support, 194 * which is very simple and depends on the presence of a 195 * /var/yp/securenets file, and tcp-wrapper support, which requires 196 * Wietse Venema's libwrap.a and tcpd.h. (Since the tcp-wrapper 197 * package does not ship with FreeBSD, we use the built-in support 198 * by default. Users can recompile the server with the tcp-wrapper library 199 * if they already have it installed and want to use hosts.allow and 200 * hosts.deny to control access instead of having a separate securenets 201 * file.) 202 * 203 * If no /var/yp/securenets file is present, the host access checks 204 * are bypassed and all hosts are allowed to connect. 205 * 206 * The yp_validdomain() function checks the domain specified by the caller 207 * to make sure it's actually served by this server. This is more a sanity 208 * check than an a security check, but this seems to be the best place for 209 * it. 210 */ 211 212 #ifdef DB_CACHE 213 int 214 yp_access(const char *map, const char *domain, const struct svc_req *rqstp) 215 #else 216 int 217 yp_access(const char *map, const struct svc_req *rqstp) 218 #endif 219 { 220 struct sockaddr_in *rqhost; 221 int status = 0; 222 static unsigned long oldaddr = 0; 223 #ifndef TCP_WRAPPER 224 struct securenet *tmp; 225 #endif 226 char *yp_procedure = NULL; 227 char procbuf[50]; 228 229 if (rqstp->rq_prog != YPPASSWDPROG && rqstp->rq_prog != YPPROG) { 230 snprintf(procbuf, sizeof(procbuf), "#%lu/#%lu", rqstp->rq_prog, 231 rqstp->rq_proc); 232 yp_procedure = (char *)&procbuf; 233 } else { 234 yp_procedure = rqstp->rq_prog == YPPASSWDPROG ? 235 "yppasswdprog_update" : 236 yp_procs[rqstp->rq_proc + (12 * (rqstp->rq_vers - 1))]; 237 } 238 239 rqhost = svc_getcaller(rqstp->rq_xprt); 240 241 if (debug) { 242 yp_error("procedure %s called from %s:%d", yp_procedure, 243 inet_ntoa(rqhost->sin_addr), 244 ntohs(rqhost->sin_port)); 245 if (map != NULL) 246 yp_error("client is referencing map \"%s\".", map); 247 } 248 249 /* Check the map name if one was supplied. */ 250 if (map != NULL) { 251 if (strchr(map, '/')) { 252 yp_error("embedded slash in map name \"%s\" -- \ 253 possible spoof attempt from %s:%d", 254 map, inet_ntoa(rqhost->sin_addr), 255 ntohs(rqhost->sin_port)); 256 return(1); 257 } 258 #ifdef DB_CACHE 259 if ((yp_testflag((char *)map, (char *)domain, YP_SECURE) || 260 #else 261 if ((strstr(map, "master.passwd.") || 262 #endif 263 (rqstp->rq_prog == YPPROG && 264 rqstp->rq_proc == YPPROC_XFR) || 265 (rqstp->rq_prog == YPXFRD_FREEBSD_PROG && 266 rqstp->rq_proc == YPXFRD_GETMAP)) && 267 ntohs(rqhost->sin_port) >= IPPORT_RESERVED) { 268 yp_error("access to %s denied -- client %s:%d \ 269 not privileged", map, inet_ntoa(rqhost->sin_addr), ntohs(rqhost->sin_port)); 270 return(1); 271 } 272 } 273 274 #ifdef TCP_WRAPPER 275 status = hosts_ctl("ypserv", STRING_UNKNOWN, 276 inet_ntoa(rqhost->sin_addr), ""); 277 #else 278 tmp = securenets; 279 while (tmp) { 280 if (((rqhost->sin_addr.s_addr & ~tmp->mask.s_addr) 281 | tmp->net.s_addr) == rqhost->sin_addr.s_addr) { 282 status = 1; 283 break; 284 } 285 tmp = tmp->next; 286 } 287 #endif 288 289 if (!status) { 290 if (rqhost->sin_addr.s_addr != oldaddr) { 291 yp_error("connect from %s:%d to procedure %s refused", 292 inet_ntoa(rqhost->sin_addr), 293 ntohs(rqhost->sin_port), 294 yp_procedure); 295 oldaddr = rqhost->sin_addr.s_addr; 296 } 297 return(1); 298 } 299 return(0); 300 301 } 302 303 int 304 yp_validdomain(const char *domain) 305 { 306 struct stat statbuf; 307 char dompath[MAXPATHLEN + 2]; 308 309 if (domain == NULL || strstr(domain, "binding") || 310 !strcmp(domain, ".") || !strcmp(domain, "..") || 311 strchr(domain, '/') || strlen(domain) > YPMAXDOMAIN) 312 return(1); 313 314 snprintf(dompath, sizeof(dompath), "%s/%s", yp_dir, domain); 315 316 if (stat(dompath, &statbuf) < 0 || !S_ISDIR(statbuf.st_mode)) 317 return(1); 318 319 320 return(0); 321 } 322