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 #ifndef lint 35 static const char rcsid[] = 36 "$FreeBSD: src/usr.sbin/ypserv/yp_access.c,v 1.17.2.1 2002/02/15 00:47:00 des Exp $"; 37 #endif /* not lint */ 38 39 #include <stdlib.h> 40 #include <rpc/rpc.h> 41 #include <rpcsvc/yp.h> 42 #include <rpcsvc/yppasswd.h> 43 #include <rpcsvc/ypxfrd.h> 44 #include <sys/types.h> 45 #include <limits.h> 46 #include <db.h> 47 #include <sys/socket.h> 48 #include <netinet/in.h> 49 #include <arpa/inet.h> 50 #include <sys/stat.h> 51 #include <sys/fcntl.h> 52 #include <paths.h> 53 #include <errno.h> 54 #include <sys/param.h> 55 #include "yp_extern.h" 56 #ifdef TCP_WRAPPER 57 #include "tcpd.h" 58 #endif 59 60 extern int debug; 61 62 /* NIS v1 */ 63 char *yp_procs[] = { "ypoldproc_null", 64 "ypoldproc_domain", 65 "ypoldproc_domain_nonack", 66 "ypoldproc_match", 67 "ypoldproc_first", 68 "ypoldproc_next", 69 "ypoldproc_poll", 70 "ypoldproc_push", 71 "ypoldproc_get", 72 "badproc1", /* placeholder */ 73 "badproc2", /* placeholder */ 74 "badproc3", /* placeholder */ 75 76 /* NIS v2 */ 77 "ypproc_null", 78 "ypproc_domain", 79 "ypproc_domain_nonack", 80 "ypproc_match", 81 "ypproc_first", 82 "ypproc_next", 83 "ypproc_xfr", 84 "ypproc_clear", 85 "ypproc_all", 86 "ypproc_master", 87 "ypproc_order", 88 "ypproc_maplist" 89 }; 90 91 92 #ifdef TCP_WRAPPER 93 void load_securenets() 94 { 95 } 96 #else 97 struct securenet { 98 struct in_addr net; 99 struct in_addr mask; 100 struct securenet *next; 101 }; 102 103 struct securenet *securenets; 104 105 #define LINEBUFSZ 1024 106 107 /* 108 * Read /var/yp/securenets file and initialize the securenets 109 * list. If the file doesn't exist, we set up a dummy entry that 110 * allows all hosts to connect. 111 */ 112 void load_securenets() 113 { 114 FILE *fp; 115 char path[MAXPATHLEN + 2]; 116 char linebuf[1024 + 2]; 117 struct securenet *tmp; 118 119 /* 120 * If securenets is not NULL, we are being called to reload 121 * the list; free the existing list before re-reading the 122 * securenets file. 123 */ 124 while (securenets) { 125 tmp = securenets->next; 126 free(securenets); 127 securenets = tmp; 128 } 129 130 snprintf(path, MAXPATHLEN, "%s/securenets", yp_dir); 131 132 if ((fp = fopen(path, "r")) == NULL) { 133 if (errno == ENOENT) { 134 securenets = (struct securenet *)malloc(sizeof(struct securenet)); 135 securenets->net.s_addr = INADDR_ANY; 136 securenets->mask.s_addr = INADDR_ANY; 137 securenets->next = NULL; 138 return; 139 } else { 140 yp_error("fopen(%s) failed: %s", path, strerror(errno)); 141 exit(1); 142 } 143 } 144 145 securenets = NULL; 146 147 while (fgets(linebuf, LINEBUFSZ, fp)) { 148 char addr1[20], addr2[20]; 149 150 if ((linebuf[0] == '#') 151 || (strspn(linebuf, " \t\r\n") == strlen(linebuf))) 152 continue; 153 if (sscanf(linebuf, "%s %s", addr1, addr2) < 2) { 154 yp_error("badly formatted securenets entry: %s", 155 linebuf); 156 continue; 157 } 158 159 tmp = (struct securenet *)malloc(sizeof(struct securenet)); 160 161 if (!inet_aton((char *)&addr1, (struct in_addr *)&tmp->net)) { 162 yp_error("badly formatted securenets entry: %s", addr1); 163 free(tmp); 164 continue; 165 } 166 167 if (!inet_aton((char *)&addr2, (struct in_addr *)&tmp->mask)) { 168 yp_error("badly formatted securenets entry: %s", addr2); 169 free(tmp); 170 continue; 171 } 172 173 tmp->next = securenets; 174 securenets = tmp; 175 } 176 177 fclose(fp); 178 179 } 180 #endif 181 182 /* 183 * Access control functions. 184 * 185 * yp_access() checks the mapname and client host address and watches for 186 * the following things: 187 * 188 * - If the client is referencing one of the master.passwd.* maps, it must 189 * be using a privileged port to make its RPC to us. If it is, then we can 190 * assume that the caller is root and allow the RPC to succeed. If it 191 * isn't access is denied. 192 * 193 * - The client's IP address is checked against the securenets rules. 194 * There are two kinds of securenets support: the built-in support, 195 * which is very simple and depends on the presence of a 196 * /var/yp/securenets file, and tcp-wrapper support, which requires 197 * Wietse Venema's libwrap.a and tcpd.h. (Since the tcp-wrapper 198 * package does not ship with FreeBSD, we use the built-in support 199 * by default. Users can recompile the server with the tcp-wrapper library 200 * if they already have it installed and want to use hosts.allow and 201 * hosts.deny to control access instead of having a seperate securenets 202 * file.) 203 * 204 * If no /var/yp/securenets file is present, the host access checks 205 * are bypassed and all hosts are allowed to connect. 206 * 207 * The yp_validdomain() function checks the domain specified by the caller 208 * to make sure it's actually served by this server. This is more a sanity 209 * check than an a security check, but this seems to be the best place for 210 * it. 211 */ 212 213 #ifdef DB_CACHE 214 int yp_access(map, domain, rqstp) 215 #else 216 int yp_access(map, rqstp) 217 #endif 218 const char *map; 219 #ifdef DB_CACHE 220 const char *domain; 221 #endif 222 const struct svc_req *rqstp; 223 { 224 struct sockaddr_in *rqhost; 225 int status = 0; 226 static unsigned long oldaddr = 0; 227 #ifndef TCP_WRAPPER 228 struct securenet *tmp; 229 #endif 230 char *yp_procedure = NULL; 231 char procbuf[50]; 232 233 if (rqstp->rq_prog != YPPASSWDPROG && rqstp->rq_prog != YPPROG) { 234 snprintf(procbuf, sizeof(procbuf), "#%lu/#%lu", rqstp->rq_prog, 235 rqstp->rq_proc); 236 yp_procedure = (char *)&procbuf; 237 } else { 238 yp_procedure = rqstp->rq_prog == YPPASSWDPROG ? 239 "yppasswdprog_update" : 240 yp_procs[rqstp->rq_proc + (12 * (rqstp->rq_vers - 1))]; 241 } 242 243 rqhost = svc_getcaller(rqstp->rq_xprt); 244 245 if (debug) { 246 yp_error("procedure %s called from %s:%d", yp_procedure, 247 inet_ntoa(rqhost->sin_addr), 248 ntohs(rqhost->sin_port)); 249 if (map != NULL) 250 yp_error("client is referencing map \"%s\".", map); 251 } 252 253 /* Check the map name if one was supplied. */ 254 if (map != NULL) { 255 if (strchr(map, '/')) { 256 yp_error("embedded slash in map name \"%s\" -- \ 257 possible spoof attempt from %s:%d", 258 map, inet_ntoa(rqhost->sin_addr), 259 ntohs(rqhost->sin_port)); 260 return(1); 261 } 262 #ifdef DB_CACHE 263 if ((yp_testflag((char *)map, (char *)domain, YP_SECURE) || 264 #else 265 if ((strstr(map, "master.passwd.") || 266 #endif 267 (rqstp->rq_prog == YPPROG && 268 rqstp->rq_proc == YPPROC_XFR) || 269 (rqstp->rq_prog == YPXFRD_FREEBSD_PROG && 270 rqstp->rq_proc == YPXFRD_GETMAP)) && 271 ntohs(rqhost->sin_port) >= IPPORT_RESERVED) { 272 yp_error("access to %s denied -- client %s:%d \ 273 not privileged", map, inet_ntoa(rqhost->sin_addr), ntohs(rqhost->sin_port)); 274 return(1); 275 } 276 } 277 278 #ifdef TCP_WRAPPER 279 status = hosts_ctl("ypserv", STRING_UNKNOWN, 280 inet_ntoa(rqhost->sin_addr), ""); 281 #else 282 tmp = securenets; 283 while (tmp) { 284 if (((rqhost->sin_addr.s_addr & ~tmp->mask.s_addr) 285 | tmp->net.s_addr) == rqhost->sin_addr.s_addr) { 286 status = 1; 287 break; 288 } 289 tmp = tmp->next; 290 } 291 #endif 292 293 if (!status) { 294 if (rqhost->sin_addr.s_addr != oldaddr) { 295 yp_error("connect from %s:%d to procedure %s refused", 296 inet_ntoa(rqhost->sin_addr), 297 ntohs(rqhost->sin_port), 298 yp_procedure); 299 oldaddr = rqhost->sin_addr.s_addr; 300 } 301 return(1); 302 } 303 return(0); 304 305 } 306 307 int yp_validdomain(domain) 308 const char *domain; 309 { 310 struct stat statbuf; 311 char dompath[MAXPATHLEN + 2]; 312 313 if (domain == NULL || strstr(domain, "binding") || 314 !strcmp(domain, ".") || !strcmp(domain, "..") || 315 strchr(domain, '/') || strlen(domain) > YPMAXDOMAIN) 316 return(1); 317 318 snprintf(dompath, sizeof(dompath), "%s/%s", yp_dir, domain); 319 320 if (stat(dompath, &statbuf) < 0 || !S_ISDIR(statbuf.st_mode)) 321 return(1); 322 323 324 return(0); 325 } 326