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