1 /* $OpenBSD: yp_bind.c,v 1.20 2014/05/25 17:47:04 tedu Exp $ */ 2 /* 3 * Copyright (c) 1992, 1993, 1996 Theo de Raadt <deraadt@theos.com> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 16 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 19 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #include <sys/param.h> 29 #include <sys/types.h> 30 #include <sys/socket.h> 31 #include <sys/uio.h> 32 #include <errno.h> 33 #include <fcntl.h> 34 #include <stdio.h> 35 #include <stdlib.h> 36 #include <string.h> 37 #include <unistd.h> 38 #include <rpc/rpc.h> 39 #include <rpc/xdr.h> 40 #include <rpcsvc/yp.h> 41 #include <rpcsvc/ypclnt.h> 42 #include "ypinternal.h" 43 44 struct dom_binding *_ypbindlist; 45 char _yp_domain[MAXHOSTNAMELEN]; 46 int _yplib_timeout = 10; 47 48 int 49 _yp_dobind(const char *dom, struct dom_binding **ypdb) 50 { 51 static pid_t pid = -1; 52 char path[PATH_MAX]; 53 struct dom_binding *ysd, *ysd2; 54 struct ypbind_resp ypbr; 55 struct timeval tv; 56 struct sockaddr_in clnt_sin; 57 struct ypbind_binding *bn; 58 int clnt_sock, fd; 59 pid_t gpid; 60 CLIENT *client; 61 int new = 0, r; 62 int count = 0; 63 u_short port; 64 65 /* 66 * test if YP is running or not 67 */ 68 if ((fd = open(YPBINDLOCK, O_RDONLY)) == -1) 69 return YPERR_YPBIND; 70 if (!(flock(fd, LOCK_EX | LOCK_NB) == -1 && errno == EWOULDBLOCK)) { 71 (void)close(fd); 72 return YPERR_YPBIND; 73 } 74 (void)close(fd); 75 76 gpid = getpid(); 77 if (!(pid == -1 || pid == gpid)) { 78 ysd = _ypbindlist; 79 while (ysd) { 80 if (ysd->dom_client) 81 clnt_destroy(ysd->dom_client); 82 ysd2 = ysd->dom_pnext; 83 free(ysd); 84 ysd = ysd2; 85 } 86 _ypbindlist = NULL; 87 } 88 pid = gpid; 89 90 if (ypdb != NULL) 91 *ypdb = NULL; 92 93 if (dom == NULL || strlen(dom) == 0) 94 return YPERR_BADARGS; 95 96 for (ysd = _ypbindlist; ysd; ysd = ysd->dom_pnext) 97 if (strcmp(dom, ysd->dom_domain) == 0) 98 break; 99 if (ysd == NULL) { 100 if ((ysd = calloc(1, sizeof *ysd)) == NULL) 101 return YPERR_RESRC; 102 ysd->dom_socket = -1; 103 ysd->dom_vers = 0; 104 new = 1; 105 } 106 again: 107 if (ysd->dom_vers == 0) { 108 r = snprintf(path, sizeof(path), "%s/%s.%d", 109 BINDINGDIR, dom, 2); 110 if (r < 0 || r >= sizeof(path)) { 111 if (new) 112 free(ysd); 113 return YPERR_BADARGS; 114 } 115 if ((fd = open(path, O_RDONLY)) == -1) { 116 /* 117 * no binding file, YP is dead, or not yet fully 118 * alive. 119 */ 120 goto trynet; 121 } 122 if (flock(fd, LOCK_EX | LOCK_NB) == -1 && 123 errno == EWOULDBLOCK) { 124 struct iovec iov[2]; 125 u_short ypb_port; 126 127 /* 128 * we fetch the ypbind port number, but do 129 * nothing with it. 130 */ 131 iov[0].iov_base = (caddr_t) &ypb_port; 132 iov[0].iov_len = sizeof ypb_port; 133 iov[1].iov_base = (caddr_t) &ypbr; 134 iov[1].iov_len = sizeof ypbr; 135 136 r = readv(fd, iov, 2); 137 if (r != iov[0].iov_len + iov[1].iov_len) { 138 (void)close(fd); 139 ysd->dom_vers = -1; 140 goto again; 141 } 142 (void)close(fd); 143 goto gotdata; 144 } else { 145 /* no lock on binding file, YP is dead. */ 146 (void)close(fd); 147 if (new) 148 free(ysd); 149 return YPERR_YPBIND; 150 } 151 } 152 trynet: 153 if (ysd->dom_vers == -1 || ysd->dom_vers == 0) { 154 (void)memset(&clnt_sin, 0, sizeof clnt_sin); 155 clnt_sin.sin_len = sizeof(struct sockaddr_in); 156 clnt_sin.sin_family = AF_INET; 157 clnt_sin.sin_addr.s_addr = htonl(INADDR_LOOPBACK); 158 159 clnt_sock = RPC_ANYSOCK; 160 client = clnttcp_create(&clnt_sin, YPBINDPROG, YPBINDVERS, 161 &clnt_sock, 0, 0); 162 if (client == NULL) { 163 clnt_pcreateerror("clnttcp_create"); 164 if (new) 165 free(ysd); 166 switch (rpc_createerr.cf_error.re_errno) { 167 case ECONNREFUSED: 168 return YPERR_YPBIND; 169 case ENOMEM: 170 return YPERR_RESRC; 171 default: 172 return YPERR_YPERR; 173 } 174 } 175 if (ntohs(clnt_sin.sin_port) >= IPPORT_RESERVED || 176 ntohs(clnt_sin.sin_port) == 20) { 177 /* 178 * YP was not running, but someone has registered 179 * ypbind with portmap -- this simply means YP is 180 * not running. 181 */ 182 clnt_destroy(client); 183 if (new) 184 free(ysd); 185 return YPERR_YPBIND; 186 } 187 tv.tv_sec = _yplib_timeout; 188 tv.tv_usec = 0; 189 r = clnt_call(client, YPBINDPROC_DOMAIN, xdr_domainname, 190 &dom, xdr_ypbind_resp, &ypbr, tv); 191 if (r != RPC_SUCCESS) { 192 if (new == 0 || count) 193 fprintf(stderr, 194 "YP server for domain %s not responding, still trying\n", 195 dom); 196 count++; 197 clnt_destroy(client); 198 ysd->dom_vers = -1; 199 goto again; 200 } 201 clnt_destroy(client); 202 gotdata: 203 bn = &ypbr.ypbind_resp_u.ypbind_bindinfo; 204 memcpy(&port, &bn->ypbind_binding_port, sizeof port); 205 if (ntohs(port) >= IPPORT_RESERVED || 206 ntohs(port) == 20) { 207 /* 208 * This is bullshit -- the ypbind wants me to 209 * communicate to an insecure ypserv. We are 210 * within rights to syslog this as an attack, 211 * but for now we'll simply ignore it; real YP 212 * is obviously not running. 213 */ 214 if (new) 215 free(ysd); 216 return YPERR_YPBIND; 217 } 218 (void)memset(&ysd->dom_server_addr, 0, 219 sizeof ysd->dom_server_addr); 220 ysd->dom_server_addr.sin_len = sizeof(struct sockaddr_in); 221 ysd->dom_server_addr.sin_family = AF_INET; 222 memcpy(&ysd->dom_server_addr.sin_port, 223 &bn->ypbind_binding_port, 224 sizeof(ysd->dom_server_addr.sin_port)); 225 memcpy(&ysd->dom_server_addr.sin_addr.s_addr, 226 &bn->ypbind_binding_addr, 227 sizeof(ysd->dom_server_addr.sin_addr.s_addr)); 228 ysd->dom_server_port = ysd->dom_server_addr.sin_port; 229 ysd->dom_vers = YPVERS; 230 strlcpy(ysd->dom_domain, dom, sizeof ysd->dom_domain); 231 } 232 tv.tv_sec = _yplib_timeout / 2; 233 tv.tv_usec = 0; 234 if (ysd->dom_client) 235 clnt_destroy(ysd->dom_client); 236 ysd->dom_socket = RPC_ANYSOCK; 237 ysd->dom_client = clntudp_create(&ysd->dom_server_addr, 238 YPPROG, YPVERS, tv, &ysd->dom_socket); 239 if (ysd->dom_client == NULL) { 240 clnt_pcreateerror("clntudp_create"); 241 ysd->dom_vers = -1; 242 goto again; 243 } 244 if (fcntl(ysd->dom_socket, F_SETFD, FD_CLOEXEC) == -1) 245 perror("fcntl: F_SETFD"); 246 247 if (new) { 248 ysd->dom_pnext = _ypbindlist; 249 _ypbindlist = ysd; 250 } 251 if (ypdb != NULL) 252 *ypdb = ysd; 253 return 0; 254 } 255 256 void 257 _yp_unbind(struct dom_binding *ypb) 258 { 259 clnt_destroy(ypb->dom_client); 260 ypb->dom_client = NULL; 261 ypb->dom_socket = -1; 262 } 263 264 int 265 yp_bind(const char *dom) 266 { 267 return _yp_dobind(dom, NULL); 268 } 269 270 void 271 yp_unbind(const char *dom) 272 { 273 struct dom_binding *ypb, *ypbp; 274 275 ypbp = NULL; 276 for (ypb = _ypbindlist; ypb; ypb = ypb->dom_pnext) { 277 if (strcmp(dom, ypb->dom_domain) == 0) { 278 clnt_destroy(ypb->dom_client); 279 if (ypbp) 280 ypbp->dom_pnext = ypb->dom_pnext; 281 else 282 _ypbindlist = ypb->dom_pnext; 283 free(ypb); 284 return; 285 } 286 ypbp = ypb; 287 } 288 } 289