libexec/rshd/rshd.c

   1 /*      $NetBSD: rshd.c,v 1.46 2008/07/20 01:09:07 lukem Exp $  */
   2
   3 /*
   4  * Copyright (C) 1998 WIDE Project.
   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. All advertising materials mentioning features or use of this software
  16  *    must display the following acknowledgement:
  17  *    This product includes software developed by WIDE Project and
  18  *    its contributors.
  19  * 4. Neither the name of the project nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 /*-
  37  * Copyright (c) 1988, 1989, 1992, 1993, 1994
  38  *      The Regents of the University of California.  All rights reserved.
  39  *
  40  * Redistribution and use in source and binary forms, with or without
  41  * modification, are permitted provided that the following conditions
  42  * are met:
  43  * 1. Redistributions of source code must retain the above copyright
  44  *    notice, this list of conditions and the following disclaimer.
  45  * 2. Redistributions in binary form must reproduce the above copyright
  46  *    notice, this list of conditions and the following disclaimer in the
  47  *    documentation and/or other materials provided with the distribution.
  48  * 3. Neither the name of the University nor the names of its contributors
  49  *    may be used to endorse or promote products derived from this software
  50  *    without specific prior written permission.
  51  *
  52  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  53  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  54  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  55  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  56  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  57  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  58  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  59  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  60  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  61  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  62  * SUCH DAMAGE.
  63  */
  64
  65 #include <sys/cdefs.h>
  66 #ifndef lint
  67 __COPYRIGHT("@(#) Copyright (c) 1988, 1989, 1992, 1993, 1994\
  68  The Regents of the University of California.  All rights reserved.");
  69 #if 0
  70 static char sccsid[] = "@(#)rshd.c      8.2 (Berkeley) 4/6/94";
  71 #else
  72 __RCSID("$NetBSD: rshd.c,v 1.46 2008/07/20 01:09:07 lukem Exp $");
  73 #endif
  74 #endif /* not lint */
  75
  76 /*
  77  * remote shell server:
  78  *      [port]\0
  79  *      remuser\0
  80  *      locuser\0
  81  *      command\0
  82  *      data
  83  */
  84 #include <sys/param.h>
  85 #include <sys/ioctl.h>
  86 #include <sys/time.h>
  87 #include <sys/socket.h>
  88
  89 #include <netinet/in_systm.h>
  90 #include <netinet/in.h>
  91 #include <netinet/ip.h>
  92 #include <netinet/tcp.h>
  93 #include <arpa/inet.h>
  94 #include <netdb.h>
  95
  96 #include <errno.h>
  97 #include <fcntl.h>
  98 #include <paths.h>
  99 #include <pwd.h>
 100 #include <signal.h>
 101 #include <stdio.h>
 102 #include <stdlib.h>
 103 #include <string.h>
 104 #include <syslog.h>
 105 #include <unistd.h>
 106 #include <poll.h>
 107 #ifdef  LOGIN_CAP
 108 #include <login_cap.h>
 109 #endif
 110
 111 #ifdef USE_PAM
 112 #include <security/pam_appl.h>
 113 #include <security/openpam.h>
 114 #include <sys/wait.h>
 115
 116 static struct pam_conv pamc = { openpam_nullconv, NULL };
 117 static pam_handle_t *pamh;
 118 static int pam_err;
 119
 120 #define PAM_END do { \
 121         if ((pam_err = pam_setcred(pamh, PAM_DELETE_CRED)) != PAM_SUCCESS) \
 122                 syslog(LOG_ERR|LOG_AUTH, "pam_setcred(): %s", \
 123                     pam_strerror(pamh, pam_err)); \
 124         if ((pam_err = pam_close_session(pamh,0)) != PAM_SUCCESS) \
 125                 syslog(LOG_ERR|LOG_AUTH, "pam_close_session(): %s", \
 126                     pam_strerror(pamh, pam_err)); \
 127         if ((pam_err = pam_end(pamh, pam_err)) != PAM_SUCCESS) \
 128                 syslog(LOG_ERR|LOG_AUTH, "pam_end(): %s", \
 129                     pam_strerror(pamh, pam_err)); \
 130 } while (/*CONSTCOND*/0)
 131 #else
 132 #define PAM_END
 133 #endif
 134
 135 int     keepalive = 1;
 136 int     check_all;
 137 int     log_success;            /* If TRUE, log all successful accesses */
 138 int     sent_null;
 139
 140 void     doit(struct sockaddr *) __dead;
 141 void     rshd_errx(int, const char *, ...)
 142      __attribute__((__noreturn__, __format__(__printf__, 2, 3)));
 143 void     getstr(char *, int, const char *);
 144 int      local_domain(char *);
 145 char    *topdomain(char *);
 146 void     usage(void);
 147 int      main(int, char *[]);
 148
 149 #define OPTIONS "aLln"
 150 extern int __check_rhosts_file;
 151 extern char *__rcmd_errstr;     /* syslog hook from libc/net/rcmd.c. */
 152 static const char incorrect[] = "Login incorrect.";
 153
 154 int
 155 main(int argc, char *argv[])
 156 {
 157         struct linger linger;
 158         int ch, on = 1;
 159         socklen_t fromlen;
 160         struct sockaddr_storage from;
 161         struct protoent *proto;
 162
 163         openlog("rshd", LOG_PID, LOG_DAEMON);
 164
 165         opterr = 0;
 166         while ((ch = getopt(argc, argv, OPTIONS)) != -1)
 167                 switch (ch) {
 168                 case 'a':
 169                         check_all = 1;
 170                         break;
 171                 case 'l':
 172                         __check_rhosts_file = 0;
 173                         break;
 174                 case 'n':
 175                         keepalive = 0;
 176                         break;
 177                 case 'L':
 178                         log_success = 1;
 179                         break;
 180                 case '?':
 181                 default:
 182                         usage();
 183                         break;
 184                 }
 185
 186         argc -= optind;
 187         argv += optind;
 188
 189         fromlen = sizeof(from); /* xxx */
 190         if (getpeername(STDIN_FILENO, (struct sockaddr *)&from, &fromlen) < 0) {
 191                 syslog(LOG_ERR, "getpeername: %m");
 192                 return EXIT_FAILURE;
 193         }
 194 #if 0
 195         if (((struct sockaddr *)&from)->sa_family == AF_INET6 &&
 196             IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&from)->sin6_addr) &&
 197             sizeof(struct sockaddr_in) <= sizeof(from)) {
 198                 struct sockaddr_in sin;
 199                 struct sockaddr_in6 *sin6;
 200                 const int off = sizeof(struct sockaddr_in6) -
 201                     sizeof(struct sockaddr_in);
 202
 203                 sin6 = (struct sockaddr_in6 *)&from;
 204                 (void)memset(&sin, 0, sizeof(sin));
 205                 sin.sin_family = AF_INET;
 206                 sin.sin_len = sizeof(struct sockaddr_in);
 207                 (void)memcpy(&sin.sin_addr, &sin6->sin6_addr.s6_addr[off],
 208                     sizeof(sin.sin_addr));
 209                 (void)memcpy(&from, &sin, sizeof(sin));
 210                 fromlen = sin.sin_len;
 211         }
 212 #else
 213         if (((struct sockaddr *)&from)->sa_family == AF_INET6 &&
 214             IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&from)->sin6_addr)) {
 215                 char hbuf[NI_MAXHOST];
 216                 if (getnameinfo((struct sockaddr *)&from, fromlen, hbuf,
 217                                 sizeof(hbuf), NULL, 0, NI_NUMERICHOST) != 0) {
 218                         strlcpy(hbuf, "invalid", sizeof(hbuf));
 219                 }
 220                 syslog(LOG_ERR, "malformed \"from\" address (v4 mapped, %s)",
 221                     hbuf);
 222                 return EXIT_FAILURE;
 223         }
 224 #endif
 225         if (keepalive &&
 226             setsockopt(STDIN_FILENO, SOL_SOCKET, SO_KEEPALIVE, (char *)&on,
 227             sizeof(on)) < 0)
 228                 syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m");
 229         linger.l_onoff = 1;
 230         linger.l_linger = 60;                   /* XXX */
 231         if (setsockopt(STDIN_FILENO, SOL_SOCKET, SO_LINGER, (char *)&linger,
 232             sizeof (linger)) < 0)
 233                 syslog(LOG_WARNING, "setsockopt (SO_LINGER): %m");
 234         proto = getprotobyname("tcp");
 235         (void)setsockopt(STDIN_FILENO, proto->p_proto, TCP_NODELAY, &on,
 236             sizeof(on));
 237         doit((struct sockaddr *)&from);
 238 }
 239
 240 char    username[20] = "USER=";
 241 char    homedir[64] = "HOME=";
 242 char    shell[64] = "SHELL=";
 243 char    path[100] = "PATH=";
 244 char    *envinit[] =
 245             {homedir, shell, path, username, 0};
 246 char    **environ;
 247
 248 void
 249 doit(struct sockaddr *fromp)
 250 {
 251         struct passwd *pwd, pwres;
 252         in_port_t port;
 253         struct pollfd set[2];
 254         int cc, pv[2], pid, s = -1;     /* XXX gcc */
 255         int one = 1;
 256         char *hostname, *errorhost = NULL;      /* XXX gcc */
 257         const char *cp;
 258         char sig, buf[BUFSIZ];
 259         char cmdbuf[NCARGS+1], locuser[16], remuser[16];
 260         char remotehost[2 * MAXHOSTNAMELEN + 1];
 261         char hostnamebuf[2 * MAXHOSTNAMELEN + 1];
 262 #ifdef  LOGIN_CAP
 263         login_cap_t *lc;
 264 #endif
 265         char naddr[NI_MAXHOST];
 266         char saddr[NI_MAXHOST];
 267         char raddr[NI_MAXHOST];
 268         char pbuf[NI_MAXSERV];
 269         int af = fromp->sa_family;
 270         u_int16_t *portp;
 271         struct addrinfo hints, *res, *res0;
 272         int gaierror;
 273         const int niflags = NI_NUMERICHOST | NI_NUMERICSERV;
 274         const char *errormsg = NULL, *errorstr = NULL;
 275         char pwbuf[1024];
 276
 277         (void)signal(SIGINT, SIG_DFL);
 278         (void)signal(SIGQUIT, SIG_DFL);
 279         (void)signal(SIGTERM, SIG_DFL);
 280 #ifdef DEBUG
 281         {
 282                 int t = open(_PATH_TTY, O_RDWR);
 283                 if (t >= 0) {
 284                         ioctl(t, TIOCNOTTY, NULL);
 285                         (void)close(t);
 286                 }
 287         }
 288 #endif
 289         switch (af) {
 290         case AF_INET:
 291                 portp = &((struct sockaddr_in *)fromp)->sin_port;
 292                 break;
 293 #ifdef INET6
 294         case AF_INET6:
 295                 portp = &((struct sockaddr_in6 *)fromp)->sin6_port;
 296                 break;
 297 #endif
 298         default:
 299                 syslog(LOG_ERR, "malformed \"from\" address (af %d)", af);
 300                 exit(EXIT_FAILURE);
 301         }
 302         if (getnameinfo(fromp, fromp->sa_len, naddr, sizeof(naddr),
 303                         pbuf, sizeof(pbuf), niflags) != 0) {
 304                 syslog(LOG_ERR, "malformed \"from\" address (af %d)", af);
 305                 exit(EXIT_FAILURE);
 306         }
 307 #ifdef IP_OPTIONS
 308         if (af == AF_INET) {
 309
 310         u_char optbuf[BUFSIZ/3];
 311         socklen_t optsize = sizeof(optbuf);
 312         int ipproto;
 313         unsigned int i;
 314         struct protoent *ip;
 315
 316         if ((ip = getprotobyname("ip")) != NULL)
 317                 ipproto = ip->p_proto;
 318         else
 319                 ipproto = IPPROTO_IP;
 320         if (!getsockopt(0, ipproto, IP_OPTIONS, (char *)optbuf, &optsize) &&
 321             optsize != 0) {
 322                 for (i = 0; i < optsize;) {
 323                         u_char c = optbuf[i];
 324                         if (c == IPOPT_LSRR || c == IPOPT_SSRR) {
 325                                 syslog(LOG_NOTICE,
 326                                     "Connection refused from %s "
 327                                     "with IP option %s",
 328                                     inet_ntoa((
 329                                     (struct sockaddr_in *)fromp)->sin_addr),
 330                                     c == IPOPT_LSRR ? "LSRR" : "SSRR");
 331                                 exit(EXIT_FAILURE);
 332                         }
 333                         if (c == IPOPT_EOL)
 334                                 break;
 335                         i += (c == IPOPT_NOP) ? 1 : optbuf[i + 1];
 336                 }
 337         }
 338         }
 339 #endif
 340         if (ntohs(*portp) >= IPPORT_RESERVED
 341             || ntohs(*portp) < IPPORT_RESERVED / 2) {
 342                 syslog(LOG_NOTICE|LOG_AUTH,
 343                     "Connection from %s on illegal port %u",
 344                     naddr, ntohs(*portp));
 345                 exit(EXIT_FAILURE);
 346         }
 347
 348         (void) alarm(60);
 349         port = 0;
 350         for (;;) {
 351                 char c;
 352
 353                 if ((cc = read(STDIN_FILENO, &c, 1)) != 1) {
 354                         if (cc < 0)
 355                                 syslog(LOG_ERR, "read: %m");
 356                         (void)shutdown(0, SHUT_RDWR);
 357                         exit(EXIT_FAILURE);
 358                 }
 359                 if (c == 0)
 360                         break;
 361                 port = port * 10 + c - '0';
 362         }
 363
 364         (void) alarm(0);
 365         if (port != 0) {
 366                 int lport = IPPORT_RESERVED - 1;
 367                 s = rresvport_af(&lport, af);
 368                 if (s < 0) {
 369                         syslog(LOG_ERR, "can't get stderr port: %m");
 370                         exit(EXIT_FAILURE);
 371                 }
 372                 if (port >= IPPORT_RESERVED) {
 373                         syslog(LOG_ERR, "2nd port not reserved");
 374                         exit(EXIT_FAILURE);
 375                 }
 376                 *portp = htons(port);
 377                 if (connect(s, fromp, fromp->sa_len) < 0) {
 378                         syslog(LOG_ERR, "connect second port %d: %m", port);
 379                         exit(EXIT_FAILURE);
 380                 }
 381         }
 382
 383
 384 #ifdef notdef
 385         /* from inetd, socket is already on 0, 1, 2 */
 386         (void)dup2(f, STDIN_FILENO);
 387         (void)dup2(f, STDOUT_FILENO);
 388         (void)dup2(f, STDERR_FILENO);
 389 #endif
 390         if (getnameinfo(fromp, fromp->sa_len, saddr, sizeof(saddr),
 391                         NULL, 0, NI_NAMEREQD) == 0) {
 392                 /*
 393                  * If name returned by getnameinfo is in our domain,
 394                  * attempt to verify that we haven't been fooled by someone
 395                  * in a remote net; look up the name and check that this
 396                  * address corresponds to the name.
 397                  */
 398                 hostname = saddr;
 399                 res0 = NULL;
 400                 if (check_all || local_domain(saddr)) {
 401                         (void)strlcpy(remotehost, saddr, sizeof(remotehost));
 402                         errorhost = remotehost;
 403                         (void)memset(&hints, 0, sizeof(hints));
 404                         hints.ai_family = fromp->sa_family;
 405                         hints.ai_socktype = SOCK_STREAM;
 406                         hints.ai_flags = AI_CANONNAME;
 407                         gaierror = getaddrinfo(remotehost, pbuf, &hints, &res0);
 408                         if (gaierror) {
 409                                 syslog(LOG_NOTICE,
 410                                     "Couldn't look up address for %s: %s",
 411                                     remotehost, gai_strerror(gaierror));
 412                                 errorstr =
 413                                 "Couldn't look up address for your host (%s)\n";
 414                                 hostname = naddr;
 415                         } else {
 416                                 for (res = res0; res; res = res->ai_next) {
 417                                         if (res->ai_family != fromp->sa_family)
 418                                                 continue;
 419                                         if (res->ai_addrlen != fromp->sa_len)
 420                                                 continue;
 421                                         if (getnameinfo(res->ai_addr,
 422                                                 res->ai_addrlen,
 423                                                 raddr, sizeof(raddr), NULL, 0,
 424                                                 niflags) == 0
 425                                          && strcmp(naddr, raddr) == 0) {
 426                                                 hostname = res->ai_canonname
 427                                                         ? res->ai_canonname
 428                                                         : saddr;
 429                                                 break;
 430                                         }
 431                                 }
 432                                 if (res == NULL) {
 433                                         syslog(LOG_NOTICE,
 434                                           "Host addr %s not listed for host %s",
 435                                             naddr, res0->ai_canonname
 436                                                     ? res0->ai_canonname
 437                                                     : saddr);
 438                                         errorstr =
 439                                             "Host address mismatch for %s\n";
 440                                         hostname = naddr;
 441                                 }
 442                         }
 443                 }
 444                 (void)strlcpy(hostnamebuf, hostname, sizeof(hostnamebuf));
 445                 hostname = hostnamebuf;
 446                 if (res0)
 447                         freeaddrinfo(res0);
 448         } else {
 449                 (void)strlcpy(hostnamebuf, naddr, sizeof(hostnamebuf));
 450                 errorhost = hostname = hostnamebuf;
 451         }
 452
 453         (void)alarm(60);
 454         getstr(remuser, sizeof(remuser), "remuser");
 455         getstr(locuser, sizeof(locuser), "locuser");
 456         getstr(cmdbuf, sizeof(cmdbuf), "command");
 457         (void)alarm(0);
 458
 459 #ifdef USE_PAM
 460         pam_err = pam_start("rsh", locuser, &pamc, &pamh);
 461         if (pam_err != PAM_SUCCESS) {
 462                 syslog(LOG_ERR|LOG_AUTH, "pam_start(): %s",
 463                     pam_strerror(pamh, pam_err));
 464                 rshd_errx(EXIT_FAILURE, incorrect);
 465         }
 466
 467         if ((pam_err = pam_set_item(pamh, PAM_RUSER, remuser)) != PAM_SUCCESS ||
 468             (pam_err = pam_set_item(pamh, PAM_RHOST, hostname) != PAM_SUCCESS)){
 469                 syslog(LOG_ERR|LOG_AUTH, "pam_set_item(): %s",
 470                     pam_strerror(pamh, pam_err));
 471                 rshd_errx(EXIT_FAILURE, incorrect);
 472         }
 473
 474         pam_err = pam_authenticate(pamh, 0);
 475         if (pam_err == PAM_SUCCESS) {
 476                 if ((pam_err = pam_get_user(pamh, &cp, NULL)) == PAM_SUCCESS) {
 477                         (void)strlcpy(locuser, cp, sizeof(locuser));
 478                         /* XXX truncation! */
 479                 }
 480                 pam_err = pam_acct_mgmt(pamh, 0);
 481         }
 482         if (pam_err != PAM_SUCCESS) {
 483                 errorstr = incorrect;
 484                 errormsg = pam_strerror(pamh, pam_err);
 485                 goto badlogin;
 486         }
 487 #endif /* USE_PAM */
 488         setpwent();
 489         if (getpwnam_r(locuser, &pwres, pwbuf, sizeof(pwbuf), &pwd) != 0 ||
 490             pwd == NULL) {
 491                 syslog(LOG_INFO|LOG_AUTH,
 492                     "%s@%s as %s: unknown login. cmd='%.80s'",
 493                     remuser, hostname, locuser, cmdbuf);
 494                 if (errorstr == NULL)
 495                         errorstr = "Permission denied.";
 496                 rshd_errx(EXIT_FAILURE, errorstr, errorhost);
 497         }
 498 #ifdef LOGIN_CAP
 499         lc = login_getclass(pwd ? pwd->pw_class : NULL);
 500 #endif
 501
 502         if (chdir(pwd->pw_dir) < 0) {
 503                 if (chdir("/") < 0
 504 #ifdef LOGIN_CAP
 505                     || login_getcapbool(lc, "requirehome", pwd->pw_uid ? 1 : 0)
 506 #endif
 507                 ) {
 508                         syslog(LOG_INFO|LOG_AUTH,
 509                             "%s@%s as %s: no home directory. cmd='%.80s'",
 510                             remuser, hostname, locuser, cmdbuf);
 511                         rshd_errx(EXIT_SUCCESS, "No remote home directory.");
 512                 }
 513         }
 514
 515 #ifndef USE_PAM
 516         if (errorstr ||
 517             (pwd->pw_passwd != 0 && *pwd->pw_passwd != '\0' &&
 518                 iruserok_sa(fromp, fromp->sa_len, pwd->pw_uid == 0, remuser,
 519                         locuser) < 0)) {
 520                 errormsg = __rcmd_errstr ? __rcmd_errstr : "unknown error";
 521                 if (errorstr == NULL)
 522                         errorstr = "Permission denied.";
 523                 goto badlogin;
 524         }
 525
 526         if (pwd->pw_uid && !access(_PATH_NOLOGIN, F_OK))
 527                 rshd_errx(EXIT_FAILURE, "Logins currently disabled.");
 528 #endif
 529
 530 #ifdef LOGIN_CAP
 531         /*
 532          * PAM modules might add supplementary groups in
 533          * pam_setcred(), so initialize them first.
 534          * But we need to open the session as root.
 535          */
 536         if (setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETGROUP) != 0) {
 537                 syslog(LOG_ERR, "setusercontext: %m");
 538                 exit(EXIT_FAILURE);
 539         }
 540 #else
 541         initgroups(pwd->pw_name, pwd->pw_gid);
 542 #endif
 543
 544 #ifdef USE_PAM
 545         if ((pam_err = pam_open_session(pamh, 0)) != PAM_SUCCESS) {
 546                 syslog(LOG_ERR, "pam_open_session: %s",
 547                     pam_strerror(pamh, pam_err));
 548         } else if ((pam_err = pam_setcred(pamh, PAM_ESTABLISH_CRED))
 549             != PAM_SUCCESS) {
 550                 syslog(LOG_ERR, "pam_setcred: %s", pam_strerror(pamh, pam_err));
 551         }
 552 #endif
 553
 554         (void)write(STDERR_FILENO, "\0", 1);
 555         sent_null = 1;
 556
 557         if (port) {
 558                 if (pipe(pv) < 0)
 559                         rshd_errx(EXIT_FAILURE, "Can't make pipe. (%s)",
 560                             strerror(errno));
 561                 pid = fork();
 562                 if (pid == -1)
 563                         rshd_errx(EXIT_FAILURE, "Can't fork. (%s)",
 564                             strerror(errno));
 565                 if (pid) {
 566                         (void)close(STDIN_FILENO);
 567                         (void)close(STDOUT_FILENO);
 568                         (void)close(STDERR_FILENO);
 569                         (void)close(pv[1]);
 570
 571                         set[0].fd = s;
 572                         set[0].events = POLLIN;
 573                         set[1].fd = pv[0];
 574                         set[1].events = POLLIN;
 575                         ioctl(pv[0], FIONBIO, (char *)&one);
 576
 577                         /* should set s nbio! */
 578                         do {
 579                                 if (poll(set, 2, INFTIM) < 0)
 580                                         break;
 581                                 if (set[0].revents & POLLIN) {
 582                                         int     ret;
 583
 584                                         ret = read(s, &sig, 1);
 585                                         if (ret <= 0)
 586                                                 set[0].events = 0;
 587                                         else
 588                                                 killpg(pid, sig);
 589                                 }
 590                                 if (set[1].revents & POLLIN) {
 591                                         errno = 0;
 592                                         cc = read(pv[0], buf, sizeof(buf));
 593                                         if (cc <= 0) {
 594                                                 shutdown(s, SHUT_RDWR);
 595                                                 set[1].events = 0;
 596                                         } else {
 597                                                 (void)write(s, buf, cc);
 598                                         }
 599                                 }
 600
 601                         } while ((set[0].revents | set[1].revents) & POLLIN);
 602                         PAM_END;
 603                         exit(EXIT_SUCCESS);
 604                 }
 605                 (void)close(s);
 606                 (void)close(pv[0]);
 607                 (void)dup2(pv[1], STDERR_FILENO);
 608                 close(pv[1]);
 609         }
 610 #ifdef USE_PAM
 611         else {
 612                 pid = fork();
 613                 if (pid == -1)
 614                         rshd_errx(EXIT_FAILURE, "Can't fork. (%s)",
 615                             strerror(errno));
 616                 if (pid) {
 617                         pid_t xpid;
 618                         int status;
 619                         if ((xpid = waitpid(pid, &status, 0)) != pid) {
 620                                 pam_err = pam_close_session(pamh, 0);
 621                                 if (pam_err != PAM_SUCCESS) {
 622                                         syslog(LOG_ERR,
 623                                             "pam_close_session: %s",
 624                                             pam_strerror(pamh, pam_err));
 625                                 }
 626                                 PAM_END;
 627                                 if (xpid != -1)
 628                                         syslog(LOG_WARNING,
 629                                             "wrong PID: %d != %d", pid, xpid);
 630                                 else
 631                                         syslog(LOG_WARNING,
 632                                             "wait pid=%d failed %m", pid);
 633                                 exit(EXIT_FAILURE);
 634                         }
 635                         exit(EXIT_SUCCESS);
 636                 }
 637         }
 638 #endif
 639
 640 #ifdef F_CLOSEM
 641         (void)fcntl(STDERR_FILENO + 1, F_CLOSEM, 0);
 642 #else
 643         for (fd = getdtablesize(); fd > STDERR_FILENO; fd--)
 644                 (void)close(fd);
 645 #endif
 646         if (setsid() == -1)
 647                 syslog(LOG_ERR, "setsid() failed: %m");
 648 #ifdef USE_PAM
 649         if (setlogin(pwd->pw_name) < 0)
 650                 syslog(LOG_ERR, "setlogin() failed: %m");
 651
 652         if (*pwd->pw_shell == '\0')
 653                 pwd->pw_shell = __UNCONST(_PATH_BSHELL);
 654
 655         (void)pam_setenv(pamh, "HOME", pwd->pw_dir, 1);
 656         (void)pam_setenv(pamh, "SHELL", pwd->pw_shell, 1);
 657         (void)pam_setenv(pamh, "USER", pwd->pw_name, 1);
 658         (void)pam_setenv(pamh, "PATH", _PATH_DEFPATH, 1);
 659         environ = pam_getenvlist(pamh);
 660         (void)pam_end(pamh, pam_err);
 661 #else
 662 #ifdef LOGIN_CAP
 663         {
 664                 char *sh;
 665                 if ((sh = login_getcapstr(lc, "shell", NULL, NULL))) {
 666                         if(!(sh = strdup(sh))) {
 667                                 syslog(LOG_ERR, "Cannot alloc mem");
 668                                 exit(EXIT_FAILURE);
 669                         }
 670                         pwd->pw_shell = sh;
 671                 }
 672         }
 673 #endif
 674         environ = envinit;
 675         (void)strlcat(homedir, pwd->pw_dir, sizeof(homedir));
 676         (void)strlcat(path, _PATH_DEFPATH, sizeof(path));
 677         (void)strlcat(shell, pwd->pw_shell, sizeof(shell));
 678         (void)strlcat(username, pwd->pw_name, sizeof(username));
 679 #endif
 680
 681         cp = strrchr(pwd->pw_shell, '/');
 682         if (cp)
 683                 cp++;
 684         else
 685                 cp = pwd->pw_shell;
 686
 687 #ifdef LOGIN_CAP
 688         if (setusercontext(lc, pwd, pwd->pw_uid,
 689                 LOGIN_SETALL & ~LOGIN_SETGROUP) < 0) {
 690                 syslog(LOG_ERR, "setusercontext(): %m");
 691                 exit(EXIT_FAILURE);
 692         }
 693         login_close(lc);
 694 #else
 695         (void)setgid((gid_t)pwd->pw_gid);
 696         (void)setuid((uid_t)pwd->pw_uid);
 697 #endif
 698         endpwent();
 699         if (log_success || pwd->pw_uid == 0) {
 700                 syslog(LOG_INFO|LOG_AUTH, "%s@%s as %s: cmd='%.80s'",
 701                     remuser, hostname, locuser, cmdbuf);
 702         }
 703         (void)execl(pwd->pw_shell, cp, "-c", cmdbuf, NULL);
 704         rshd_errx(EXIT_FAILURE, "%s: %s", pwd->pw_shell, strerror(errno));
 705 badlogin:
 706         syslog(LOG_INFO|LOG_AUTH,
 707             "%s@%s as %s: permission denied (%s). cmd='%.80s'",
 708             remuser, hostname, locuser, errormsg, cmdbuf);
 709         rshd_errx(EXIT_FAILURE, errorstr, errorhost);
 710 }
 711
 712 /*
 713  * Report error to client.  Note: can't be used until second socket has
 714  * connected to client, or older clients will hang waiting for that
 715  * connection first.
 716  */
 717
 718 #include <stdarg.h>
 719
 720 void
 721 rshd_errx(int error, const char *fmt, ...)
 722 {
 723         va_list ap;
 724         int len, rv;
 725         char *bp, buf[BUFSIZ];
 726         va_start(ap, fmt);
 727         bp = buf;
 728         if (sent_null == 0) {
 729                 *bp++ = 1;
 730                 len = 1;
 731         } else
 732                 len = 0;
 733         rv = vsnprintf(bp, sizeof(buf) - 2, fmt, ap);
 734         bp[rv++] = '\n';
 735         (void)write(STDERR_FILENO, buf, len + rv);
 736         va_end(ap);
 737         exit(error);
 738 }
 739
 740 void
 741 getstr(char *buf, int cnt, const char *err)
 742 {
 743         char c;
 744
 745         do {
 746                 if (read(STDIN_FILENO, &c, 1) != 1)
 747                         exit(EXIT_FAILURE);
 748                 *buf++ = c;
 749                 if (--cnt == 0)
 750                         rshd_errx(EXIT_FAILURE, "%s too long", err);
 751         } while (c != 0);
 752 }
 753
 754 /*
 755  * Check whether host h is in our local domain,
 756  * defined as sharing the last two components of the domain part,
 757  * or the entire domain part if the local domain has only one component.
 758  * If either name is unqualified (contains no '.'),
 759  * assume that the host is local, as it will be
 760  * interpreted as such.
 761  */
 762 int
 763 local_domain(char *h)
 764 {
 765         char localhost[MAXHOSTNAMELEN + 1];
 766         char *p1, *p2;
 767
 768         localhost[0] = 0;
 769         (void)gethostname(localhost, sizeof(localhost));
 770         localhost[sizeof(localhost) - 1] = '\0';
 771         p1 = topdomain(localhost);
 772         p2 = topdomain(h);
 773         if (p1 == NULL || p2 == NULL || !strcasecmp(p1, p2))
 774                 return (1);
 775         return (0);
 776 }
 777
 778 char *
 779 topdomain(char *h)
 780 {
 781         char *p, *maybe = NULL;
 782         int dots = 0;
 783
 784         for (p = h + strlen(h); p >= h; p--) {
 785                 if (*p == '.') {
 786                         if (++dots == 2)
 787                                 return (p);
 788                         maybe = p;
 789                 }
 790         }
 791         return (maybe);
 792 }
 793
 794 void
 795 usage(void)
 796 {
 797
 798         syslog(LOG_ERR, "Usage: %s [-%s]", getprogname(), OPTIONS);
 799         exit(EXIT_FAILURE);
 800 }