usr.sbin/ypbind/ypbind.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-3-Clause
   3  *
   4  * Copyright (c) 1992/3 Theo de Raadt <deraadt@fsa.ca>
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  * 3. The name of the author may not be used to endorse or promote
  16  *    products derived from this software without specific prior written
  17  *    permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
  20  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  21  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
  23  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 __FBSDID("$FreeBSD$");
  34
  35 #include <sys/param.h>
  36 #include <sys/types.h>
  37 #include <sys/wait.h>
  38 #include <sys/ioctl.h>
  39 #include <sys/mman.h>
  40 #include <sys/signal.h>
  41 #include <sys/socket.h>
  42 #include <sys/file.h>
  43 #include <sys/fcntl.h>
  44 #include <sys/stat.h>
  45 #include <sys/uio.h>
  46 #include <ctype.h>
  47 #include <dirent.h>
  48 #include <err.h>
  49 #include <errno.h>
  50 #include <netdb.h>
  51 #include <signal.h>
  52 #include <stdio.h>
  53 #include <stdlib.h>
  54 #include <string.h>
  55 #include <syslog.h>
  56 #include <unistd.h>
  57 #include <rpc/rpc.h>
  58 #include <rpc/xdr.h>
  59 #include <net/if.h>
  60 #include <netinet/in.h>
  61 #include <arpa/inet.h>
  62 #include <rpc/pmap_clnt.h>
  63 #include <rpc/pmap_prot.h>
  64 #include <rpc/pmap_rmt.h>
  65 #include <rpc/rpc_com.h>
  66 #include <rpcsvc/yp.h>
  67 #include <rpcsvc/ypclnt.h>
  68 #include "yp_ping.h"
  69
  70 #ifndef BINDINGDIR
  71 #define BINDINGDIR "/var/yp/binding"
  72 #endif
  73
  74 #ifndef YPBINDLOCK
  75 #define YPBINDLOCK "/var/run/ypbind.lock"
  76 #endif
  77
  78 struct _dom_binding {
  79         struct _dom_binding *dom_pnext;
  80         char dom_domain[YPMAXDOMAIN + 1];
  81         struct sockaddr_in dom_server_addr;
  82         long int dom_vers;
  83         int dom_lockfd;
  84         int dom_alive;
  85         int dom_broadcast_pid;
  86         int dom_pipe_fds[2];
  87         int dom_default;
  88 };
  89
  90 #define READFD ypdb->dom_pipe_fds[0]
  91 #define WRITEFD ypdb->dom_pipe_fds[1]
  92 #define BROADFD broad_domain->dom_pipe_fds[1]
  93
  94 extern bool_t xdr_domainname(), xdr_ypbind_resp();
  95 extern bool_t xdr_ypreq_key(), xdr_ypresp_val();
  96 extern bool_t xdr_ypbind_setdom();
  97
  98 void    checkwork(void);
  99 void    *ypbindproc_null_2_yp(SVCXPRT *, void *, CLIENT *);
 100 void    *ypbindproc_setdom_2_yp(SVCXPRT *, struct ypbind_setdom *, CLIENT *);
 101 void    rpc_received(char *, struct sockaddr_in *, int);
 102 void    broadcast(struct _dom_binding *);
 103 int     ping(struct _dom_binding *);
 104 int     tell_parent(char *, struct sockaddr_in *);
 105 void    handle_children(struct _dom_binding *);
 106 void    reaper(int);
 107 void    terminate(int);
 108 void    yp_restricted_mode(char *);
 109 int     verify(struct in_addr);
 110
 111 static char *domain_name;
 112 static struct _dom_binding *ypbindlist;
 113 static struct _dom_binding *broad_domain;
 114
 115 #define YPSET_NO        0
 116 #define YPSET_LOCAL     1
 117 #define YPSET_ALL       2
 118 static int ypsetmode = YPSET_NO;
 119 static int ypsecuremode = 0;
 120 static int ppid;
 121
 122 #define NOT_RESPONDING_HYSTERESIS 10
 123 static int not_responding_count = 0;
 124
 125 /*
 126  * Special restricted mode variables: when in restricted mode, only the
 127  * specified restricted_domain will be bound, and only the servers listed
 128  * in restricted_addrs will be used for binding.
 129  */
 130 #define RESTRICTED_SERVERS 10
 131 static int yp_restricted = 0;
 132 static int yp_manycast = 0;
 133 static struct in_addr restricted_addrs[RESTRICTED_SERVERS];
 134
 135 /* No more than MAX_CHILDREN child broadcasters at a time. */
 136 #ifndef MAX_CHILDREN
 137 #define MAX_CHILDREN 5
 138 #endif
 139 /* No more than MAX_DOMAINS simultaneous domains */
 140 #ifndef MAX_DOMAINS
 141 #define MAX_DOMAINS 200
 142 #endif
 143 /* RPC timeout value */
 144 #ifndef FAIL_THRESHOLD
 145 #define FAIL_THRESHOLD 20
 146 #endif
 147
 148 /* Number of times to fish for a response froma particular set of hosts */
 149 #ifndef MAX_RETRIES
 150 #define MAX_RETRIES 30
 151 #endif
 152
 153 static int retries = 0;
 154 static int children = 0;
 155 static int domains = 0;
 156 static int yplockfd;
 157 static fd_set fdsr;
 158
 159 static SVCXPRT *udptransp, *tcptransp;
 160
 161 void *
 162 ypbindproc_null_2_yp(SVCXPRT *transp, void *argp, CLIENT *clnt)
 163 {
 164         static char res;
 165
 166         bzero(&res, sizeof(res));
 167         return &res;
 168 }
 169
 170 static struct ypbind_resp *
 171 ypbindproc_domain_2_yp(SVCXPRT *transp, domainname *argp, CLIENT *clnt)
 172 {
 173         static struct ypbind_resp res;
 174         struct _dom_binding *ypdb;
 175         char path[MAXPATHLEN];
 176
 177         bzero(&res, sizeof res);
 178         res.ypbind_status = YPBIND_FAIL_VAL;
 179         res.ypbind_resp_u.ypbind_error = YPBIND_ERR_NOSERV;
 180
 181         if (strchr(*argp, '/')) {
 182                 syslog(LOG_WARNING, "Domain name '%s' has embedded slash -- \
 183 rejecting.", *argp);
 184                 return(&res);
 185         }
 186
 187         for (ypdb = ypbindlist; ypdb; ypdb = ypdb->dom_pnext) {
 188                 if (strcmp(ypdb->dom_domain, *argp) == 0)
 189                         break;
 190                 }
 191
 192         if (ypdb == NULL) {
 193                 if (yp_restricted) {
 194                         syslog(LOG_NOTICE, "Running in restricted mode -- request to bind domain \"%s\" rejected.\n", *argp);
 195                         return (&res);
 196                 }
 197
 198                 if (domains >= MAX_DOMAINS) {
 199                         syslog(LOG_WARNING, "domain limit (%d) exceeded",
 200                                                         MAX_DOMAINS);
 201                         res.ypbind_resp_u.ypbind_error = YPBIND_ERR_RESC;
 202                         return (&res);
 203                 }
 204                 if (strlen(*argp) > YPMAXDOMAIN) {
 205                         syslog(LOG_WARNING, "domain %s too long", *argp);
 206                         res.ypbind_resp_u.ypbind_error = YPBIND_ERR_RESC;
 207                         return (&res);
 208                 }
 209                 ypdb = malloc(sizeof *ypdb);
 210                 if (ypdb == NULL) {
 211                         syslog(LOG_WARNING, "malloc: %m");
 212                         res.ypbind_resp_u.ypbind_error = YPBIND_ERR_RESC;
 213                         return (&res);
 214                 }
 215                 bzero(ypdb, sizeof *ypdb);
 216                 strlcpy(ypdb->dom_domain, *argp, sizeof ypdb->dom_domain);
 217                 ypdb->dom_vers = YPVERS;
 218                 ypdb->dom_alive = 0;
 219                 ypdb->dom_default = 0;
 220                 ypdb->dom_lockfd = -1;
 221                 sprintf(path, "%s/%s.%ld", BINDINGDIR,
 222                                         ypdb->dom_domain, ypdb->dom_vers);
 223                 unlink(path);
 224                 ypdb->dom_pnext = ypbindlist;
 225                 ypbindlist = ypdb;
 226                 domains++;
 227         }
 228
 229         if (ping(ypdb)) {
 230                 return (&res);
 231         }
 232
 233         res.ypbind_status = YPBIND_SUCC_VAL;
 234         res.ypbind_resp_u.ypbind_error = 0; /* Success */
 235         memcpy(&res.ypbind_resp_u.ypbind_bindinfo.ypbind_binding_addr,
 236             &ypdb->dom_server_addr.sin_addr.s_addr, sizeof(u_int32_t));
 237         memcpy(&res.ypbind_resp_u.ypbind_bindinfo.ypbind_binding_port,
 238             &ypdb->dom_server_addr.sin_port, sizeof(u_short));
 239         /*printf("domain %s at %s/%d\n", ypdb->dom_domain,
 240                 inet_ntoa(ypdb->dom_server_addr.sin_addr),
 241                 ntohs(ypdb->dom_server_addr.sin_port));*/
 242         return (&res);
 243 }
 244
 245 void *
 246 ypbindproc_setdom_2_yp(SVCXPRT *transp, ypbind_setdom *argp, CLIENT *clnt)
 247 {
 248         struct sockaddr_in *fromsin, bindsin;
 249         static char             *result = NULL;
 250
 251         if (strchr(argp->ypsetdom_domain, '/')) {
 252                 syslog(LOG_WARNING, "Domain name '%s' has embedded slash -- \
 253 rejecting.", argp->ypsetdom_domain);
 254                 return(NULL);
 255         }
 256         fromsin = svc_getcaller(transp);
 257
 258         switch (ypsetmode) {
 259         case YPSET_LOCAL:
 260                 if (fromsin->sin_addr.s_addr != htonl(INADDR_LOOPBACK)) {
 261                         svcerr_noprog(transp);
 262                         return(NULL);
 263                 }
 264                 break;
 265         case YPSET_ALL:
 266                 break;
 267         case YPSET_NO:
 268         default:
 269                 svcerr_noprog(transp);
 270                 return(NULL);
 271         }
 272
 273         if (ntohs(fromsin->sin_port) >= IPPORT_RESERVED) {
 274                 svcerr_noprog(transp);
 275                 return(NULL);
 276         }
 277
 278         if (argp->ypsetdom_vers != YPVERS) {
 279                 svcerr_noprog(transp);
 280                 return(NULL);
 281         }
 282
 283         bzero(&bindsin, sizeof bindsin);
 284         bindsin.sin_family = AF_INET;
 285         memcpy(&bindsin.sin_addr.s_addr,
 286             &argp->ypsetdom_binding.ypbind_binding_addr,
 287             sizeof(u_int32_t));
 288         memcpy(&bindsin.sin_port,
 289             &argp->ypsetdom_binding.ypbind_binding_port,
 290             sizeof(u_short));
 291         rpc_received(argp->ypsetdom_domain, &bindsin, 1);
 292
 293         return((void *) &result);
 294 }
 295
 296 void
 297 ypbindprog_2(struct svc_req *rqstp, register SVCXPRT *transp)
 298 {
 299         union {
 300                 domainname ypbindproc_domain_2_arg;
 301                 struct ypbind_setdom ypbindproc_setdom_2_arg;
 302         } argument;
 303         struct authunix_parms *creds;
 304         char *result;
 305         bool_t (*xdr_argument)(), (*xdr_result)();
 306         char *(*local)();
 307
 308         switch (rqstp->rq_proc) {
 309         case YPBINDPROC_NULL:
 310                 xdr_argument = xdr_void;
 311                 xdr_result = xdr_void;
 312                 local = (char *(*)()) ypbindproc_null_2_yp;
 313                 break;
 314
 315         case YPBINDPROC_DOMAIN:
 316                 xdr_argument = xdr_domainname;
 317                 xdr_result = xdr_ypbind_resp;
 318                 local = (char *(*)()) ypbindproc_domain_2_yp;
 319                 break;
 320
 321         case YPBINDPROC_SETDOM:
 322                 switch (rqstp->rq_cred.oa_flavor) {
 323                 case AUTH_UNIX:
 324                         creds = (struct authunix_parms *)rqstp->rq_clntcred;
 325                         if (creds->aup_uid != 0) {
 326                                 svcerr_auth(transp, AUTH_BADCRED);
 327                                 return;
 328                         }
 329                         break;
 330                 default:
 331                         svcerr_auth(transp, AUTH_TOOWEAK);
 332                         return;
 333                 }
 334
 335                 xdr_argument = xdr_ypbind_setdom;
 336                 xdr_result = xdr_void;
 337                 local = (char *(*)()) ypbindproc_setdom_2_yp;
 338                 break;
 339
 340         default:
 341                 svcerr_noproc(transp);
 342                 return;
 343         }
 344         bzero(&argument, sizeof(argument));
 345         if (!svc_getargs(transp, (xdrproc_t)xdr_argument, &argument)) {
 346                 svcerr_decode(transp);
 347                 return;
 348         }
 349         result = (*local)(transp, &argument, rqstp);
 350         if (result != NULL &&
 351             !svc_sendreply(transp, (xdrproc_t)xdr_result, result)) {
 352                 svcerr_systemerr(transp);
 353         }
 354         return;
 355 }
 356
 357 /* Jack the reaper */
 358 void
 359 reaper(int sig)
 360 {
 361         int st;
 362
 363         while (wait3(&st, WNOHANG, NULL) > 0)
 364                 children--;
 365 }
 366
 367 void
 368 terminate(int sig)
 369 {
 370         struct _dom_binding *ypdb;
 371         char path[MAXPATHLEN];
 372
 373         if (ppid != getpid())
 374                 exit(0);
 375
 376         for (ypdb = ypbindlist; ypdb; ypdb = ypdb->dom_pnext) {
 377                 close(ypdb->dom_lockfd);
 378                 if (ypdb->dom_broadcast_pid)
 379                         kill(ypdb->dom_broadcast_pid, SIGINT);
 380                 sprintf(path, "%s/%s.%ld", BINDINGDIR,
 381                         ypdb->dom_domain, ypdb->dom_vers);
 382                 unlink(path);
 383         }
 384         close(yplockfd);
 385         unlink(YPBINDLOCK);
 386         pmap_unset(YPBINDPROG, YPBINDVERS);
 387         exit(0);
 388 }
 389
 390 int
 391 main(int argc, char *argv[])
 392 {
 393         struct timeval tv;
 394         int i;
 395         DIR *dird;
 396         struct dirent *dirp;
 397         struct _dom_binding *ypdb, *next;
 398
 399         /* Check that another ypbind isn't already running. */
 400         if ((yplockfd = (open(YPBINDLOCK, O_RDONLY|O_CREAT, 0444))) == -1)
 401                 err(1, "%s", YPBINDLOCK);
 402
 403         if (flock(yplockfd, LOCK_EX|LOCK_NB) == -1 && errno == EWOULDBLOCK)
 404                 errx(1, "another ypbind is already running. Aborting");
 405
 406         /* XXX domainname will be overridden if we use restricted mode */
 407         yp_get_default_domain(&domain_name);
 408         if (domain_name[0] == '\0')
 409                 errx(1, "domainname not set. Aborting");
 410
 411         for (i = 1; i<argc; i++) {
 412                 if (strcmp("-ypset", argv[i]) == 0)
 413                         ypsetmode = YPSET_ALL;
 414                 else if (strcmp("-ypsetme", argv[i]) == 0)
 415                         ypsetmode = YPSET_LOCAL;
 416                 else if (strcmp("-s", argv[i]) == 0)
 417                         ypsecuremode++;
 418                 else if (strcmp("-S", argv[i]) == 0 && argc > i)
 419                         yp_restricted_mode(argv[++i]);
 420                 else if (strcmp("-m", argv[i]) == 0)
 421                         yp_manycast++;
 422                 else
 423                         errx(1, "unknown option: %s", argv[i]);
 424         }
 425
 426         if (strlen(domain_name) > YPMAXDOMAIN)
 427                 warnx("truncating domain name %s", domain_name);
 428
 429         /* blow away everything in BINDINGDIR (if it exists) */
 430
 431         if ((dird = opendir(BINDINGDIR)) != NULL) {
 432                 char path[MAXPATHLEN];
 433                 while ((dirp = readdir(dird)) != NULL)
 434                         if (strcmp(dirp->d_name, ".") &&
 435                             strcmp(dirp->d_name, "..")) {
 436                                 sprintf(path,"%s/%s",BINDINGDIR,dirp->d_name);
 437                                 unlink(path);
 438                         }
 439                 closedir(dird);
 440         }
 441
 442 #ifdef DAEMON
 443         if (daemon(0,0))
 444                 err(1, "fork");
 445 #endif
 446
 447         pmap_unset(YPBINDPROG, YPBINDVERS);
 448
 449         udptransp = svcudp_create(RPC_ANYSOCK);
 450         if (udptransp == NULL)
 451                 errx(1, "cannot create udp service");
 452         if (!svc_register(udptransp, YPBINDPROG, YPBINDVERS, ypbindprog_2,
 453             IPPROTO_UDP))
 454                 errx(1, "unable to register (YPBINDPROG, YPBINDVERS, udp)");
 455
 456         tcptransp = svctcp_create(RPC_ANYSOCK, 0, 0);
 457         if (tcptransp == NULL)
 458                 errx(1, "cannot create tcp service");
 459
 460         if (!svc_register(tcptransp, YPBINDPROG, YPBINDVERS, ypbindprog_2,
 461             IPPROTO_TCP))
 462                 errx(1, "unable to register (YPBINDPROG, YPBINDVERS, tcp)");
 463
 464         /* build initial domain binding, make it "unsuccessful" */
 465         ypbindlist = malloc(sizeof *ypbindlist);
 466         if (ypbindlist == NULL)
 467                 errx(1, "malloc");
 468         bzero(ypbindlist, sizeof *ypbindlist);
 469         strlcpy(ypbindlist->dom_domain, domain_name, sizeof ypbindlist->dom_domain);
 470         ypbindlist->dom_vers = YPVERS;
 471         ypbindlist->dom_alive = 0;
 472         ypbindlist->dom_lockfd = -1;
 473         ypbindlist->dom_default = 1;
 474         domains++;
 475
 476         signal(SIGCHLD, reaper);
 477         signal(SIGTERM, terminate);
 478
 479         ppid = getpid(); /* Remember who we are. */
 480
 481         openlog(argv[0], LOG_PID, LOG_DAEMON);
 482
 483         if (madvise(NULL, 0, MADV_PROTECT) != 0)
 484                 syslog(LOG_WARNING, "madvise(): %m");
 485
 486         /* Kick off the default domain */
 487         broadcast(ypbindlist);
 488
 489         while (1) {
 490                 fdsr = svc_fdset;
 491
 492                 tv.tv_sec = 60;
 493                 tv.tv_usec = 0;
 494
 495                 switch (select(_rpc_dtablesize(), &fdsr, NULL, NULL, &tv)) {
 496                 case 0:
 497                         checkwork();
 498                         break;
 499                 case -1:
 500                         if (errno != EINTR)
 501                                 syslog(LOG_WARNING, "select: %m");
 502                         break;
 503                 default:
 504                         for (ypdb = ypbindlist; ypdb; ypdb = next) {
 505                                 next = ypdb->dom_pnext;
 506                                 if (READFD > 0 && FD_ISSET(READFD, &fdsr)) {
 507                                         handle_children(ypdb);
 508                                         if (children == (MAX_CHILDREN - 1))
 509                                                 checkwork();
 510                                 }
 511                         }
 512                         svc_getreqset(&fdsr);
 513                         break;
 514                 }
 515         }
 516
 517         /* NOTREACHED */
 518         exit(1);
 519 }
 520
 521 void
 522 checkwork(void)
 523 {
 524         struct _dom_binding *ypdb;
 525
 526         for (ypdb = ypbindlist; ypdb; ypdb = ypdb->dom_pnext)
 527                 ping(ypdb);
 528 }
 529
 530 /* The clnt_broadcast() callback mechanism sucks. */
 531
 532 /*
 533  * Receive results from broadcaster. Don't worry about passing
 534  * bogus info to rpc_received() -- it can handle it. Note that we
 535  * must be sure to invalidate the dom_pipe_fds descriptors here:
 536  * since descriptors can be re-used, we have to make sure we
 537  * don't mistake one of the RPC descriptors for one of the pipes.
 538  * What's weird is that forgetting to invalidate the pipe descriptors
 539  * doesn't always result in an error (otherwise I would have caught
 540  * the mistake much sooner), even though logically it should.
 541  */
 542 void
 543 handle_children(struct _dom_binding *ypdb)
 544 {
 545         char buf[YPMAXDOMAIN + 1];
 546         struct sockaddr_in addr;
 547         int d = 0, a = 0;
 548         struct _dom_binding *y, *prev = NULL;
 549         char path[MAXPATHLEN];
 550
 551         if ((d = read(READFD, &buf, sizeof(buf))) <= 0)
 552                 syslog(LOG_WARNING, "could not read from child: %m");
 553
 554         if ((a = read(READFD, &addr, sizeof(struct sockaddr_in))) < 0)
 555                 syslog(LOG_WARNING, "could not read from child: %m");
 556
 557         close(READFD);
 558         FD_CLR(READFD, &fdsr);
 559         FD_CLR(READFD, &svc_fdset);
 560         READFD = WRITEFD = -1;
 561         if (d > 0 && a > 0)
 562                 rpc_received(buf, &addr, 0);
 563         else {
 564                 for (y = ypbindlist; y; y = y->dom_pnext) {
 565                         if (y == ypdb)
 566                                 break;
 567                         prev = y;
 568                 }
 569                 switch (ypdb->dom_default) {
 570                 case 0:
 571                         if (prev == NULL)
 572                                 ypbindlist = y->dom_pnext;
 573                         else
 574                                 prev->dom_pnext = y->dom_pnext;
 575                         sprintf(path, "%s/%s.%ld", BINDINGDIR,
 576                                 ypdb->dom_domain, YPVERS);
 577                         close(ypdb->dom_lockfd);
 578                         unlink(path);
 579                         free(ypdb);
 580                         domains--;
 581                         return;
 582                 case 1:
 583                         ypdb->dom_broadcast_pid = 0;
 584                         ypdb->dom_alive = 0;
 585                         broadcast(ypdb);
 586                         return;
 587                 default:
 588                         break;
 589                 }
 590         }
 591
 592         return;
 593 }
 594
 595 /*
 596  * Send our dying words back to our parent before we perish.
 597  */
 598 int
 599 tell_parent(char *dom, struct sockaddr_in *addr)
 600 {
 601         char buf[YPMAXDOMAIN + 1];
 602         struct timeval timeout;
 603         fd_set fds;
 604
 605         timeout.tv_sec = 5;
 606         timeout.tv_usec = 0;
 607
 608         sprintf(buf, "%s", broad_domain->dom_domain);
 609         if (write(BROADFD, &buf, sizeof(buf)) < 0)
 610                 return(1);
 611
 612         /*
 613          * Stay in sync with parent: wait for it to read our first
 614          * message before sending the second.
 615          */
 616
 617         FD_ZERO(&fds);
 618         FD_SET(BROADFD, &fds);
 619         if (select(FD_SETSIZE, NULL, &fds, NULL, &timeout) == -1)
 620                 return(1);
 621         if (FD_ISSET(BROADFD, &fds)) {
 622                 if (write(BROADFD, addr, sizeof(struct sockaddr_in)) < 0)
 623                         return(1);
 624         } else {
 625                 return(1);
 626         }
 627
 628         close(BROADFD);
 629         return (0);
 630 }
 631
 632 static bool_t
 633 broadcast_result(bool_t *out, struct sockaddr_in *addr)
 634 {
 635         if (retries >= MAX_RETRIES) {
 636                 bzero(addr, sizeof(struct sockaddr_in));
 637                 if (tell_parent(broad_domain->dom_domain, addr))
 638                         syslog(LOG_WARNING, "lost connection to parent");
 639                 return (TRUE);
 640         }
 641
 642         if (yp_restricted && verify(addr->sin_addr)) {
 643                 retries++;
 644                 syslog(LOG_NOTICE, "NIS server at %s not in restricted mode access list -- rejecting.\n",inet_ntoa(addr->sin_addr));
 645                 return (FALSE);
 646         } else {
 647                 if (tell_parent(broad_domain->dom_domain, addr))
 648                         syslog(LOG_WARNING, "lost connection to parent");
 649                 return (TRUE);
 650         }
 651 }
 652
 653 /*
 654  * The right way to send RPC broadcasts.
 655  * Use the clnt_broadcast() RPC service. Unfortunately, clnt_broadcast()
 656  * blocks while waiting for replies, so we have to fork off separate
 657  * broadcaster processes that do the waiting and then transmit their
 658  * results back to the parent for processing. We also have to remember
 659  * to save the name of the domain we're trying to bind in a global
 660  * variable since clnt_broadcast() provides no way to pass things to
 661  * the 'eachresult' callback function.
 662  */
 663 void
 664 broadcast(struct _dom_binding *ypdb)
 665 {
 666         bool_t out = FALSE;
 667         enum clnt_stat stat;
 668
 669         if (children >= MAX_CHILDREN || ypdb->dom_broadcast_pid)
 670                 return;
 671
 672         if (pipe(ypdb->dom_pipe_fds) < 0) {
 673                 syslog(LOG_WARNING, "pipe: %m");
 674                 return;
 675         }
 676
 677         if (ypdb->dom_vers == -1 && (long)ypdb->dom_server_addr.sin_addr.s_addr) {
 678                 if (not_responding_count++ >= NOT_RESPONDING_HYSTERESIS) {
 679                         not_responding_count = NOT_RESPONDING_HYSTERESIS;
 680                         syslog(LOG_WARNING, "NIS server [%s] for domain \"%s\" not responding",
 681                             inet_ntoa(ypdb->dom_server_addr.sin_addr), ypdb->dom_domain);
 682                 }
 683         }
 684
 685         broad_domain = ypdb;
 686         flock(ypdb->dom_lockfd, LOCK_UN);
 687
 688         switch ((ypdb->dom_broadcast_pid = fork())) {
 689         case 0:
 690                 close(READFD);
 691                 signal(SIGCHLD, SIG_DFL);
 692                 signal(SIGTERM, SIG_DFL);
 693                 break;
 694         case -1:
 695                 syslog(LOG_WARNING, "fork: %m");
 696                 close(READFD);
 697                 close(WRITEFD);
 698                 return;
 699         default:
 700                 close(WRITEFD);
 701                 FD_SET(READFD, &svc_fdset);
 702                 children++;
 703                 return;
 704         }
 705
 706         /* Release all locks before doing anything else. */
 707         while (ypbindlist) {
 708                 close(ypbindlist->dom_lockfd);
 709                 ypbindlist = ypbindlist->dom_pnext;
 710         }
 711         close(yplockfd);
 712
 713         /*
 714          * Special 'many-cast' behavior. If we're in restricted mode,
 715          * we have a list of possible server addresses to try. What
 716          * we can do is transmit to each ypserv's YPPROC_DOMAIN_NONACK
 717          * procedure and time the replies. Whoever replies fastest
 718          * gets to be our server. Note that this is not a broadcast
 719          * operation: we transmit uni-cast datagrams only.
 720          */
 721         if (yp_restricted && yp_manycast) {
 722                 short                   port;
 723                 int                     i;
 724                 struct sockaddr_in      sin;
 725
 726                 i = __yp_ping(restricted_addrs, yp_restricted,
 727                                 ypdb->dom_domain, &port);
 728                 if (i == -1) {
 729                         bzero(&ypdb->dom_server_addr,
 730                             sizeof(struct sockaddr_in));
 731                         if (tell_parent(ypdb->dom_domain,
 732                                 &ypdb->dom_server_addr))
 733                         syslog(LOG_WARNING, "lost connection to parent");
 734                 } else {
 735                         bzero(&sin, sizeof(struct sockaddr_in));
 736                         bcopy(&restricted_addrs[i],
 737                             &sin.sin_addr, sizeof(struct in_addr));
 738                         sin.sin_family = AF_INET;
 739                         sin.sin_port = port;
 740                         if (tell_parent(broad_domain->dom_domain, &sin))
 741                                 syslog(LOG_WARNING,
 742                                         "lost connection to parent");
 743                 }
 744                 _exit(0);
 745         }
 746
 747         retries = 0;
 748
 749         {
 750                 char *ptr;
 751
 752                 ptr = ypdb->dom_domain;
 753                 stat = clnt_broadcast(YPPROG, YPVERS, YPPROC_DOMAIN_NONACK,
 754                         (xdrproc_t)xdr_domainname, &ptr,
 755                         (xdrproc_t)xdr_bool, &out,
 756                         (resultproc_t)broadcast_result);
 757         }
 758
 759         if (stat != RPC_SUCCESS) {
 760                 bzero(&ypdb->dom_server_addr,
 761                     sizeof(struct sockaddr_in));
 762                 if (tell_parent(ypdb->dom_domain, &ypdb->dom_server_addr))
 763                         syslog(LOG_WARNING, "lost connection to parent");
 764         }
 765
 766         _exit(0);
 767 }
 768
 769 /*
 770  * The right way to check if a server is alive.
 771  * Attempt to get a client handle pointing to the server and send a
 772  * YPPROC_DOMAIN. If we can't get a handle or we get a reply of FALSE,
 773  * we invalidate this binding entry and send out a broadcast to try to
 774  * establish a new binding. Note that we treat non-default domains
 775  * specially: once bound, we keep tabs on our server, but if it
 776  * goes away and fails to respond after one round of broadcasting, we
 777  * abandon it until a client specifically references it again. We make
 778  * every effort to keep our default domain bound, however, since we
 779  * need it to keep the system on its feet.
 780  */
 781 int
 782 ping(struct _dom_binding *ypdb)
 783 {
 784         bool_t out;
 785         struct timeval interval, timeout;
 786         enum clnt_stat stat;
 787         int rpcsock = RPC_ANYSOCK;
 788         CLIENT *client_handle;
 789
 790         interval.tv_sec = FAIL_THRESHOLD;
 791         interval.tv_usec = 0;
 792         timeout.tv_sec = FAIL_THRESHOLD;
 793         timeout.tv_usec = 0;
 794
 795         if (ypdb->dom_broadcast_pid)
 796                 return(1);
 797
 798         if ((client_handle = clntudp_bufcreate(&ypdb->dom_server_addr,
 799                 YPPROG, YPVERS, interval, &rpcsock, RPCSMALLMSGSIZE,
 800                 RPCSMALLMSGSIZE)) == (CLIENT *)NULL) {
 801                 /* Can't get a handle: we're dead. */
 802                 ypdb->dom_alive = 0;
 803                 ypdb->dom_vers = -1;
 804                 broadcast(ypdb);
 805                 return(1);
 806         }
 807
 808         {
 809                 char *ptr;
 810
 811                 ptr = ypdb->dom_domain;
 812
 813                 stat = clnt_call(client_handle, YPPROC_DOMAIN,
 814                     (xdrproc_t)xdr_domainname, &ptr,
 815                     (xdrproc_t)xdr_bool, &out, timeout);
 816                 if (stat != RPC_SUCCESS || out == FALSE) {
 817                         ypdb->dom_alive = 0;
 818                         ypdb->dom_vers = -1;
 819                         clnt_destroy(client_handle);
 820                         broadcast(ypdb);
 821                         return(1);
 822                 }
 823         }
 824
 825         clnt_destroy(client_handle);
 826         return(0);
 827 }
 828
 829 void
 830 rpc_received(char *dom, struct sockaddr_in *raddrp, int force)
 831 {
 832         struct _dom_binding *ypdb, *prev = NULL;
 833         struct iovec iov[2];
 834         struct ypbind_resp ybr;
 835         char path[MAXPATHLEN];
 836         int fd;
 837
 838         /*printf("returned from %s/%d about %s\n", inet_ntoa(raddrp->sin_addr),
 839                ntohs(raddrp->sin_port), dom);*/
 840
 841         if (dom == NULL)
 842                 return;
 843
 844         for (ypdb = ypbindlist; ypdb; ypdb = ypdb->dom_pnext) {
 845                 if (strcmp(ypdb->dom_domain, dom) == 0)
 846                         break;
 847                 prev = ypdb;
 848         }
 849
 850         if (ypdb && force) {
 851                 if (ypdb->dom_broadcast_pid) {
 852                         kill(ypdb->dom_broadcast_pid, SIGINT);
 853                         close(READFD);
 854                         FD_CLR(READFD, &fdsr);
 855                         FD_CLR(READFD, &svc_fdset);
 856                         READFD = WRITEFD = -1;
 857                 }
 858         }
 859
 860         /* if in secure mode, check originating port number */
 861         if ((ypsecuremode && (ntohs(raddrp->sin_port) >= IPPORT_RESERVED))) {
 862             syslog(LOG_WARNING, "Rejected NIS server on [%s/%d] for domain %s.",
 863                    inet_ntoa(raddrp->sin_addr), ntohs(raddrp->sin_port),
 864                    dom);
 865             if (ypdb != NULL) {
 866                 ypdb->dom_broadcast_pid = 0;
 867                 ypdb->dom_alive = 0;
 868             }
 869             return;
 870         }
 871
 872         if (raddrp->sin_addr.s_addr == (long)0) {
 873                 switch (ypdb->dom_default) {
 874                 case 0:
 875                         if (prev == NULL)
 876                                 ypbindlist = ypdb->dom_pnext;
 877                         else
 878                                 prev->dom_pnext = ypdb->dom_pnext;
 879                         sprintf(path, "%s/%s.%ld", BINDINGDIR,
 880                                 ypdb->dom_domain, YPVERS);
 881                         close(ypdb->dom_lockfd);
 882                         unlink(path);
 883                         free(ypdb);
 884                         domains--;
 885                         return;
 886                 case 1:
 887                         ypdb->dom_broadcast_pid = 0;
 888                         ypdb->dom_alive = 0;
 889                         broadcast(ypdb);
 890                         return;
 891                 default:
 892                         break;
 893                 }
 894         }
 895
 896         if (ypdb == NULL) {
 897                 if (force == 0)
 898                         return;
 899                 if (strlen(dom) > YPMAXDOMAIN) {
 900                         syslog(LOG_WARNING, "domain %s too long", dom);
 901                         return;
 902                 }
 903                 ypdb = malloc(sizeof *ypdb);
 904                 if (ypdb == NULL) {
 905                         syslog(LOG_WARNING, "malloc: %m");
 906                         return;
 907                 }
 908                 bzero(ypdb, sizeof *ypdb);
 909                 strlcpy(ypdb->dom_domain, dom, sizeof ypdb->dom_domain);
 910                 ypdb->dom_lockfd = -1;
 911                 ypdb->dom_default = 0;
 912                 ypdb->dom_pnext = ypbindlist;
 913                 ypbindlist = ypdb;
 914         }
 915
 916         /* We've recovered from a crash: inform the world. */
 917         if (ypdb->dom_vers == -1 && ypdb->dom_server_addr.sin_addr.s_addr) {
 918                 if (not_responding_count >= NOT_RESPONDING_HYSTERESIS) {
 919                         not_responding_count = 0;
 920                         syslog(LOG_WARNING, "NIS server [%s] for domain \"%s\" OK",
 921                             inet_ntoa(raddrp->sin_addr), ypdb->dom_domain);
 922                 }
 923         }
 924
 925         bcopy(raddrp, &ypdb->dom_server_addr,
 926                 sizeof ypdb->dom_server_addr);
 927
 928         ypdb->dom_vers = YPVERS;
 929         ypdb->dom_alive = 1;
 930         ypdb->dom_broadcast_pid = 0;
 931
 932         if (ypdb->dom_lockfd != -1)
 933                 close(ypdb->dom_lockfd);
 934
 935         sprintf(path, "%s/%s.%ld", BINDINGDIR,
 936                 ypdb->dom_domain, ypdb->dom_vers);
 937 #ifdef O_SHLOCK
 938         if ((fd = open(path, O_CREAT|O_SHLOCK|O_RDWR|O_TRUNC, 0644)) == -1) {
 939                 (void)mkdir(BINDINGDIR, 0755);
 940                 if ((fd = open(path, O_CREAT|O_SHLOCK|O_RDWR|O_TRUNC, 0644)) == -1)
 941                         return;
 942         }
 943 #else
 944         if ((fd = open(path, O_CREAT|O_RDWR|O_TRUNC, 0644)) == -1) {
 945                 (void)mkdir(BINDINGDIR, 0755);
 946                 if ((fd = open(path, O_CREAT|O_RDWR|O_TRUNC, 0644)) == -1)
 947                         return;
 948         }
 949         flock(fd, LOCK_SH);
 950 #endif
 951
 952         /*
 953          * ok, if BINDINGDIR exists, and we can create the binding file,
 954          * then write to it..
 955          */
 956         ypdb->dom_lockfd = fd;
 957
 958         iov[0].iov_base = (char *)&(udptransp->xp_port);
 959         iov[0].iov_len = sizeof udptransp->xp_port;
 960         iov[1].iov_base = (char *)&ybr;
 961         iov[1].iov_len = sizeof ybr;
 962
 963         bzero(&ybr, sizeof ybr);
 964         ybr.ypbind_status = YPBIND_SUCC_VAL;
 965         memcpy(&ybr.ypbind_resp_u.ypbind_bindinfo.ypbind_binding_addr,
 966             &raddrp->sin_addr.s_addr, sizeof(u_int32_t));
 967         memcpy(&ybr.ypbind_resp_u.ypbind_bindinfo.ypbind_binding_port,
 968             &raddrp->sin_port, sizeof(u_short));
 969
 970         if (writev(ypdb->dom_lockfd, iov, 2) != iov[0].iov_len + iov[1].iov_len) {
 971                 syslog(LOG_WARNING, "write: %m");
 972                 close(ypdb->dom_lockfd);
 973                 ypdb->dom_lockfd = -1;
 974                 return;
 975         }
 976 }
 977
 978 /*
 979  * Check address against list of allowed servers. Return 0 if okay,
 980  * 1 if not matched.
 981  */
 982 int
 983 verify(struct in_addr addr)
 984 {
 985         int i;
 986
 987         for (i = 0; i < RESTRICTED_SERVERS; i++)
 988                 if (!bcmp(&addr, &restricted_addrs[i], sizeof(struct in_addr)))
 989                         return(0);
 990
 991         return(1);
 992 }
 993
 994 /*
 995  * Try to set restricted mode. We default to normal mode if we can't
 996  * resolve the specified hostnames.
 997  */
 998 void
 999 yp_restricted_mode(char *args)
1000 {
1001         struct hostent *h;
1002         int i = 0;
1003         char *s;
1004
1005         /* Find the restricted domain. */
1006         if ((s = strsep(&args, ",")) == NULL)
1007                 return;
1008         domain_name = s;
1009
1010         /* Get the addresses of the servers. */
1011         while ((s = strsep(&args, ",")) != NULL && i < RESTRICTED_SERVERS) {
1012                 if ((h = gethostbyname(s)) == NULL)
1013                         return;
1014                 bcopy (h->h_addr_list[0], &restricted_addrs[i],
1015                     sizeof(struct in_addr));
1016                 i++;
1017         }
1018
1019         /* ypset and ypsetme not allowed with restricted mode */
1020         ypsetmode = YPSET_NO;
1021
1022         yp_restricted = i;
1023         return;
1024 }