1 /* $NetBSD: rshd.c,v 1.47 2009/03/16 02:20:02 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 1.47 2009/03/16 02:20:02 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 } 801