usr.sbin/ypbind/ypbind.c

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