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