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 1.3 2004/01/08 18:39:19 asmodai 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 load_securenets() 91 { 92 } 93 #else 94 struct securenet { 95 struct in_addr net; 96 struct in_addr mask; 97 struct securenet *next; 98 }; 99 100 struct securenet *securenets; 101 102 #define LINEBUFSZ 1024 103 104 /* 105 * Read /var/yp/securenets file and initialize the securenets 106 * list. If the file doesn't exist, we set up a dummy entry that 107 * allows all hosts to connect. 108 */ 109 void load_securenets() 110 { 111 FILE *fp; 112 char path[MAXPATHLEN + 2]; 113 char linebuf[1024 + 2]; 114 struct securenet *tmp; 115 116 /* 117 * If securenets is not NULL, we are being called to reload 118 * the list; free the existing list before re-reading the 119 * securenets file. 120 */ 121 while (securenets) { 122 tmp = securenets->next; 123 free(securenets); 124 securenets = tmp; 125 } 126 127 snprintf(path, MAXPATHLEN, "%s/securenets", yp_dir); 128 129 if ((fp = fopen(path, "r")) == NULL) { 130 if (errno == ENOENT) { 131 securenets = (struct securenet *)malloc(sizeof(struct securenet)); 132 securenets->net.s_addr = INADDR_ANY; 133 securenets->mask.s_addr = INADDR_ANY; 134 securenets->next = NULL; 135 return; 136 } else { 137 yp_error("fopen(%s) failed: %s", path, strerror(errno)); 138 exit(1); 139 } 140 } 141 142 securenets = NULL; 143 144 while (fgets(linebuf, LINEBUFSZ, fp)) { 145 char addr1[20], addr2[20]; 146 147 if ((linebuf[0] == '#') 148 || (strspn(linebuf, " \t\r\n") == strlen(linebuf))) 149 continue; 150 if (sscanf(linebuf, "%s %s", addr1, addr2) < 2) { 151 yp_error("badly formatted securenets entry: %s", 152 linebuf); 153 continue; 154 } 155 156 tmp = (struct securenet *)malloc(sizeof(struct securenet)); 157 158 if (!inet_aton((char *)&addr1, (struct in_addr *)&tmp->net)) { 159 yp_error("badly formatted securenets entry: %s", addr1); 160 free(tmp); 161 continue; 162 } 163 164 if (!inet_aton((char *)&addr2, (struct in_addr *)&tmp->mask)) { 165 yp_error("badly formatted securenets entry: %s", addr2); 166 free(tmp); 167 continue; 168 } 169 170 tmp->next = securenets; 171 securenets = tmp; 172 } 173 174 fclose(fp); 175 176 } 177 #endif 178 179 /* 180 * Access control functions. 181 * 182 * yp_access() checks the mapname and client host address and watches for 183 * the following things: 184 * 185 * - If the client is referencing one of the master.passwd.* maps, it must 186 * be using a privileged port to make its RPC to us. If it is, then we can 187 * assume that the caller is root and allow the RPC to succeed. If it 188 * isn't access is denied. 189 * 190 * - The client's IP address is checked against the securenets rules. 191 * There are two kinds of securenets support: the built-in support, 192 * which is very simple and depends on the presence of a 193 * /var/yp/securenets file, and tcp-wrapper support, which requires 194 * Wietse Venema's libwrap.a and tcpd.h. (Since the tcp-wrapper 195 * package does not ship with FreeBSD, we use the built-in support 196 * by default. Users can recompile the server with the tcp-wrapper library 197 * if they already have it installed and want to use hosts.allow and 198 * hosts.deny to control access instead of having a separate securenets 199 * file.) 200 * 201 * If no /var/yp/securenets file is present, the host access checks 202 * are bypassed and all hosts are allowed to connect. 203 * 204 * The yp_validdomain() function checks the domain specified by the caller 205 * to make sure it's actually served by this server. This is more a sanity 206 * check than an a security check, but this seems to be the best place for 207 * it. 208 */ 209 210 #ifdef DB_CACHE 211 int yp_access(map, domain, rqstp) 212 #else 213 int yp_access(map, rqstp) 214 #endif 215 const char *map; 216 #ifdef DB_CACHE 217 const char *domain; 218 #endif 219 const struct svc_req *rqstp; 220 { 221 struct sockaddr_in *rqhost; 222 int status = 0; 223 static unsigned long oldaddr = 0; 224 #ifndef TCP_WRAPPER 225 struct securenet *tmp; 226 #endif 227 char *yp_procedure = NULL; 228 char procbuf[50]; 229 230 if (rqstp->rq_prog != YPPASSWDPROG && rqstp->rq_prog != YPPROG) { 231 snprintf(procbuf, sizeof(procbuf), "#%lu/#%lu", rqstp->rq_prog, 232 rqstp->rq_proc); 233 yp_procedure = (char *)&procbuf; 234 } else { 235 yp_procedure = rqstp->rq_prog == YPPASSWDPROG ? 236 "yppasswdprog_update" : 237 yp_procs[rqstp->rq_proc + (12 * (rqstp->rq_vers - 1))]; 238 } 239 240 rqhost = svc_getcaller(rqstp->rq_xprt); 241 242 if (debug) { 243 yp_error("procedure %s called from %s:%d", yp_procedure, 244 inet_ntoa(rqhost->sin_addr), 245 ntohs(rqhost->sin_port)); 246 if (map != NULL) 247 yp_error("client is referencing map \"%s\".", map); 248 } 249 250 /* Check the map name if one was supplied. */ 251 if (map != NULL) { 252 if (strchr(map, '/')) { 253 yp_error("embedded slash in map name \"%s\" -- \ 254 possible spoof attempt from %s:%d", 255 map, inet_ntoa(rqhost->sin_addr), 256 ntohs(rqhost->sin_port)); 257 return(1); 258 } 259 #ifdef DB_CACHE 260 if ((yp_testflag((char *)map, (char *)domain, YP_SECURE) || 261 #else 262 if ((strstr(map, "master.passwd.") || 263 #endif 264 (rqstp->rq_prog == YPPROG && 265 rqstp->rq_proc == YPPROC_XFR) || 266 (rqstp->rq_prog == YPXFRD_FREEBSD_PROG && 267 rqstp->rq_proc == YPXFRD_GETMAP)) && 268 ntohs(rqhost->sin_port) >= IPPORT_RESERVED) { 269 yp_error("access to %s denied -- client %s:%d \ 270 not privileged", map, inet_ntoa(rqhost->sin_addr), ntohs(rqhost->sin_port)); 271 return(1); 272 } 273 } 274 275 #ifdef TCP_WRAPPER 276 status = hosts_ctl("ypserv", STRING_UNKNOWN, 277 inet_ntoa(rqhost->sin_addr), ""); 278 #else 279 tmp = securenets; 280 while (tmp) { 281 if (((rqhost->sin_addr.s_addr & ~tmp->mask.s_addr) 282 | tmp->net.s_addr) == rqhost->sin_addr.s_addr) { 283 status = 1; 284 break; 285 } 286 tmp = tmp->next; 287 } 288 #endif 289 290 if (!status) { 291 if (rqhost->sin_addr.s_addr != oldaddr) { 292 yp_error("connect from %s:%d to procedure %s refused", 293 inet_ntoa(rqhost->sin_addr), 294 ntohs(rqhost->sin_port), 295 yp_procedure); 296 oldaddr = rqhost->sin_addr.s_addr; 297 } 298 return(1); 299 } 300 return(0); 301 302 } 303 304 int yp_validdomain(domain) 305 const char *domain; 306 { 307 struct stat statbuf; 308 char dompath[MAXPATHLEN + 2]; 309 310 if (domain == NULL || strstr(domain, "binding") || 311 !strcmp(domain, ".") || !strcmp(domain, "..") || 312 strchr(domain, '/') || strlen(domain) > YPMAXDOMAIN) 313 return(1); 314 315 snprintf(dompath, sizeof(dompath), "%s/%s", yp_dir, domain); 316 317 if (stat(dompath, &statbuf) < 0 || !S_ISDIR(statbuf.st_mode)) 318 return(1); 319 320 321 return(0); 322 } 323