rshd.c revision 1.39
1 /* $NetBSD: rshd.c,v 1.39 2005/03/12 18:23:30 christos 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\n\ 68 The Regents of the University of California. All rights reserved.\n"); 69 #if 0 70 static char sccsid[] = "@(#)rshd.c 8.2 (Berkeley) 4/6/94"; 71 #else 72 __RCSID("$NetBSD: rshd.c,v 1.39 2005/03/12 18:23:30 christos 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 *); 141 void rshd_errx(int, const char *, ...) 142 __attribute__((__noreturn__, __format__(__printf__, 2, 3))); 143 void getstr(char *, int, 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, fromlen; 159 struct sockaddr_storage from; 160 struct protoent *proto; 161 162 openlog("rshd", LOG_PID, LOG_DAEMON); 163 164 opterr = 0; 165 while ((ch = getopt(argc, argv, OPTIONS)) != -1) 166 switch (ch) { 167 case 'a': 168 check_all = 1; 169 break; 170 case 'l': 171 __check_rhosts_file = 0; 172 break; 173 case 'n': 174 keepalive = 0; 175 break; 176 case 'L': 177 log_success = 1; 178 break; 179 case '?': 180 default: 181 usage(); 182 break; 183 } 184 185 argc -= optind; 186 argv += optind; 187 188 fromlen = sizeof (from); /* xxx */ 189 if (getpeername(0, (struct sockaddr *)&from, &fromlen) < 0) { 190 syslog(LOG_ERR, "getpeername: %m"); 191 exit(1); 192 } 193 #if 0 194 if (((struct sockaddr *)&from)->sa_family == AF_INET6 && 195 IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&from)->sin6_addr) && 196 sizeof(struct sockaddr_in) <= sizeof(from)) { 197 struct sockaddr_in sin; 198 struct sockaddr_in6 *sin6; 199 const int off = sizeof(struct sockaddr_in6) - 200 sizeof(struct sockaddr_in); 201 202 sin6 = (struct sockaddr_in6 *)&from; 203 memset(&sin, 0, sizeof(sin)); 204 sin.sin_family = AF_INET; 205 sin.sin_len = sizeof(struct sockaddr_in); 206 memcpy(&sin.sin_addr, &sin6->sin6_addr.s6_addr[off], 207 sizeof(sin.sin_addr)); 208 memcpy(&from, &sin, sizeof(sin)); 209 fromlen = sin.sin_len; 210 } 211 #else 212 if (((struct sockaddr *)&from)->sa_family == AF_INET6 && 213 IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&from)->sin6_addr)) { 214 char hbuf[NI_MAXHOST]; 215 if (getnameinfo((struct sockaddr *)&from, fromlen, hbuf, 216 sizeof(hbuf), NULL, 0, NI_NUMERICHOST) != 0) { 217 strlcpy(hbuf, "invalid", sizeof(hbuf)); 218 } 219 syslog(LOG_ERR, "malformed \"from\" address (v4 mapped, %s)", 220 hbuf); 221 exit(1); 222 } 223 #endif 224 if (keepalive && 225 setsockopt(0, SOL_SOCKET, SO_KEEPALIVE, (char *)&on, 226 sizeof(on)) < 0) 227 syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m"); 228 linger.l_onoff = 1; 229 linger.l_linger = 60; /* XXX */ 230 if (setsockopt(0, SOL_SOCKET, SO_LINGER, (char *)&linger, 231 sizeof (linger)) < 0) 232 syslog(LOG_WARNING, "setsockopt (SO_LINGER): %m"); 233 proto = getprotobyname("tcp"); 234 setsockopt(0, proto->p_proto, TCP_NODELAY, &on, sizeof(on)); 235 doit((struct sockaddr *)&from); 236 /* NOTREACHED */ 237 #ifdef __GNUC__ 238 exit(0); 239 #endif 240 } 241 242 char username[20] = "USER="; 243 char homedir[64] = "HOME="; 244 char shell[64] = "SHELL="; 245 char path[100] = "PATH="; 246 char *envinit[] = 247 {homedir, shell, path, username, 0}; 248 char **environ; 249 250 void 251 doit(struct sockaddr *fromp) 252 { 253 struct passwd *pwd; 254 in_port_t port; 255 struct pollfd set[2]; 256 int cc, pv[2], pid, s = -1; /* XXX gcc */ 257 int one = 1; 258 char *hostname, *errorhost = NULL; /* XXX gcc */ 259 const char *cp; 260 char sig, buf[BUFSIZ]; 261 char cmdbuf[NCARGS+1], locuser[16], remuser[16]; 262 char remotehost[2 * MAXHOSTNAMELEN + 1]; 263 char hostnamebuf[2 * MAXHOSTNAMELEN + 1]; 264 #ifdef LOGIN_CAP 265 login_cap_t *lc; 266 #endif 267 char naddr[NI_MAXHOST]; 268 char saddr[NI_MAXHOST]; 269 char raddr[NI_MAXHOST]; 270 char pbuf[NI_MAXSERV]; 271 int af = fromp->sa_family; 272 u_int16_t *portp; 273 struct addrinfo hints, *res, *res0; 274 int gaierror; 275 const int niflags = NI_NUMERICHOST | NI_NUMERICSERV; 276 const char *errormsg = NULL, *errorstr = NULL; 277 278 (void) signal(SIGINT, SIG_DFL); 279 (void) signal(SIGQUIT, SIG_DFL); 280 (void) signal(SIGTERM, SIG_DFL); 281 #ifdef DEBUG 282 { 283 int t = open(_PATH_TTY, 2); 284 if (t >= 0) { 285 ioctl(t, TIOCNOTTY, (char *)0); 286 (void)close(t); 287 } 288 } 289 #endif 290 switch (af) { 291 case AF_INET: 292 portp = &((struct sockaddr_in *)fromp)->sin_port; 293 break; 294 #ifdef INET6 295 case AF_INET6: 296 portp = &((struct sockaddr_in6 *)fromp)->sin6_port; 297 break; 298 #endif 299 default: 300 syslog(LOG_ERR, "malformed \"from\" address (af %d)", af); 301 exit(1); 302 } 303 if (getnameinfo(fromp, fromp->sa_len, naddr, sizeof(naddr), 304 pbuf, sizeof(pbuf), niflags) != 0) { 305 syslog(LOG_ERR, "malformed \"from\" address (af %d)", af); 306 exit(1); 307 } 308 #ifdef IP_OPTIONS 309 if (af == AF_INET) { 310 311 u_char optbuf[BUFSIZ/3]; 312 int optsize = sizeof(optbuf), ipproto, i; 313 struct protoent *ip; 314 315 if ((ip = getprotobyname("ip")) != NULL) 316 ipproto = ip->p_proto; 317 else 318 ipproto = IPPROTO_IP; 319 if (!getsockopt(0, ipproto, IP_OPTIONS, (char *)optbuf, &optsize) && 320 optsize != 0) { 321 for (i = 0; i < optsize;) { 322 u_char c = optbuf[i]; 323 if (c == IPOPT_LSRR || c == IPOPT_SSRR) { 324 syslog(LOG_NOTICE, 325 "Connection refused from %s " 326 "with IP option %s", 327 inet_ntoa(( 328 (struct sockaddr_in *)fromp)->sin_addr), 329 c == IPOPT_LSRR ? "LSRR" : "SSRR"); 330 exit(1); 331 } 332 if (c == IPOPT_EOL) 333 break; 334 i += (c == IPOPT_NOP) ? 1 : optbuf[i + 1]; 335 } 336 } 337 } 338 #endif 339 if (ntohs(*portp) >= IPPORT_RESERVED 340 || ntohs(*portp) < IPPORT_RESERVED/2) { 341 syslog(LOG_NOTICE|LOG_AUTH, 342 "Connection from %s on illegal port %u", 343 naddr, ntohs(*portp)); 344 exit(1); 345 } 346 347 (void) alarm(60); 348 port = 0; 349 for (;;) { 350 char c; 351 352 if ((cc = read(STDIN_FILENO, &c, 1)) != 1) { 353 if (cc < 0) 354 syslog(LOG_ERR, "read: %m"); 355 shutdown(0, SHUT_RDWR); 356 exit(1); 357 } 358 if (c == 0) 359 break; 360 port = port * 10 + c - '0'; 361 } 362 363 (void) alarm(0); 364 if (port != 0) { 365 int lport = IPPORT_RESERVED - 1; 366 s = rresvport_af(&lport, af); 367 if (s < 0) { 368 syslog(LOG_ERR, "can't get stderr port: %m"); 369 exit(1); 370 } 371 if (port >= IPPORT_RESERVED) { 372 syslog(LOG_ERR, "2nd port not reserved"); 373 exit(1); 374 } 375 *portp = htons(port); 376 if (connect(s, fromp, fromp->sa_len) < 0) { 377 syslog(LOG_ERR, "connect second port %d: %m", port); 378 exit(1); 379 } 380 } 381 382 383 #ifdef notdef 384 /* from inetd, socket is already on 0, 1, 2 */ 385 dup2(f, 0); 386 dup2(f, 1); 387 dup2(f, 2); 388 #endif 389 if (getnameinfo(fromp, fromp->sa_len, saddr, sizeof(saddr), 390 NULL, 0, NI_NAMEREQD) == 0) { 391 /* 392 * If name returned by getnameinfo is in our domain, 393 * attempt to verify that we haven't been fooled by someone 394 * in a remote net; look up the name and check that this 395 * address corresponds to the name. 396 */ 397 hostname = saddr; 398 res0 = NULL; 399 if (check_all || local_domain(saddr)) { 400 strlcpy(remotehost, saddr, sizeof(remotehost)); 401 errorhost = remotehost; 402 memset(&hints, 0, sizeof(hints)); 403 hints.ai_family = fromp->sa_family; 404 hints.ai_socktype = SOCK_STREAM; 405 hints.ai_flags = AI_CANONNAME; 406 gaierror = getaddrinfo(remotehost, pbuf, &hints, &res0); 407 if (gaierror) { 408 syslog(LOG_NOTICE, 409 "Couldn't look up address for %s: %s", 410 remotehost, gai_strerror(gaierror)); 411 errorstr = 412 "Couldn't look up address for your host (%s)\n"; 413 hostname = naddr; 414 } else { 415 for (res = res0; res; res = res->ai_next) { 416 if (res->ai_family != fromp->sa_family) 417 continue; 418 if (res->ai_addrlen != fromp->sa_len) 419 continue; 420 if (getnameinfo(res->ai_addr, 421 res->ai_addrlen, 422 raddr, sizeof(raddr), NULL, 0, 423 niflags) == 0 424 && strcmp(naddr, raddr) == 0) { 425 hostname = res->ai_canonname 426 ? res->ai_canonname 427 : saddr; 428 break; 429 } 430 } 431 if (res == NULL) { 432 syslog(LOG_NOTICE, 433 "Host addr %s not listed for host %s", 434 naddr, res0->ai_canonname 435 ? res0->ai_canonname 436 : saddr); 437 errorstr = 438 "Host address mismatch for %s\n"; 439 hostname = naddr; 440 } 441 } 442 } 443 strlcpy(hostnamebuf, hostname, sizeof(hostnamebuf)); 444 hostname = hostnamebuf; 445 if (res0) 446 freeaddrinfo(res0); 447 } else { 448 strlcpy(hostnamebuf, naddr, sizeof(hostnamebuf)); 449 errorhost = hostname = hostnamebuf; 450 } 451 452 (void)alarm(60); 453 getstr(remuser, sizeof(remuser), "remuser"); 454 getstr(locuser, sizeof(locuser), "locuser"); 455 getstr(cmdbuf, sizeof(cmdbuf), "command"); 456 (void)alarm(0); 457 458 #ifdef USE_PAM 459 pam_err = pam_start("rsh", locuser, &pamc, &pamh); 460 if (pam_err != PAM_SUCCESS) { 461 syslog(LOG_ERR|LOG_AUTH, "pam_start(): %s", 462 pam_strerror(pamh, pam_err)); 463 rshd_errx(1, incorrect); 464 } 465 466 if ((pam_err = pam_set_item(pamh, PAM_RUSER, remuser)) != PAM_SUCCESS || 467 (pam_err = pam_set_item(pamh, PAM_RHOST, hostname) != PAM_SUCCESS)){ 468 syslog(LOG_ERR|LOG_AUTH, "pam_set_item(): %s", 469 pam_strerror(pamh, pam_err)); 470 rshd_errx(1, incorrect); 471 } 472 473 pam_err = pam_authenticate(pamh, 0); 474 if (pam_err == PAM_SUCCESS) { 475 if ((pam_err = pam_get_user(pamh, &cp, NULL)) == PAM_SUCCESS) { 476 strlcpy(locuser, cp, sizeof(locuser)); 477 /* XXX truncation! */ 478 } 479 pam_err = pam_acct_mgmt(pamh, 0); 480 } 481 if (pam_err != PAM_SUCCESS) { 482 errorstr = incorrect; 483 errormsg = pam_strerror(pamh, pam_err); 484 goto badlogin; 485 } 486 #endif /* USE_PAM */ 487 setpwent(); 488 pwd = getpwnam(locuser); 489 if (pwd == NULL) { 490 syslog(LOG_INFO|LOG_AUTH, 491 "%s@%s as %s: unknown login. cmd='%.80s'", 492 remuser, hostname, locuser, cmdbuf); 493 if (errorstr == NULL) 494 errorstr = "Permission denied."; 495 rshd_errx(1, errorstr, errorhost); 496 } 497 #ifdef LOGIN_CAP 498 lc = login_getclass(pwd ? pwd->pw_class : NULL); 499 #endif 500 501 if (chdir(pwd->pw_dir) < 0) { 502 if (chdir("/") < 0 503 #ifdef LOGIN_CAP 504 || login_getcapbool(lc, "requirehome", pwd->pw_uid ? 1 : 0) 505 #endif 506 ) { 507 syslog(LOG_INFO|LOG_AUTH, 508 "%s@%s as %s: no home directory. cmd='%.80s'", 509 remuser, hostname, locuser, cmdbuf); 510 rshd_errx(0, "No remote home directory."); 511 } 512 } 513 514 #ifndef USE_PAM 515 if (errorstr || 516 (pwd->pw_passwd != 0 && *pwd->pw_passwd != '\0' && 517 iruserok_sa(fromp, fromp->sa_len, pwd->pw_uid == 0, remuser, 518 locuser) < 0)) { 519 errormsg = __rcmd_errstr ? __rcmd_errstr : "unknown error"; 520 if (errorstr == NULL) 521 errorstr = "Permission denied."; 522 goto badlogin; 523 } 524 525 if (pwd->pw_uid && !access(_PATH_NOLOGIN, F_OK)) 526 rshd_errx(1, "Logins currently disabled."); 527 #endif 528 529 #ifdef LOGIN_CAP 530 /* 531 * PAM modules might add supplementary groups in 532 * pam_setcred(), so initialize them first. 533 * But we need to open the session as root. 534 */ 535 if (setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETGROUP) != 0) { 536 syslog(LOG_ERR, "setusercontext: %m"); 537 exit(1); 538 } 539 #else 540 initgroups(pwd->pw_name, pwd->pw_gid); 541 #endif 542 543 #ifdef USE_PAM 544 if ((pam_err = pam_open_session(pamh, 0)) != PAM_SUCCESS) { 545 syslog(LOG_ERR, "pam_open_session: %s", 546 pam_strerror(pamh, pam_err)); 547 } else if ((pam_err = pam_setcred(pamh, PAM_ESTABLISH_CRED)) 548 != PAM_SUCCESS) { 549 syslog(LOG_ERR, "pam_setcred: %s", pam_strerror(pamh, pam_err)); 550 } 551 #endif 552 553 (void) write(STDERR_FILENO, "\0", 1); 554 sent_null = 1; 555 556 if (port) { 557 if (pipe(pv) < 0) 558 rshd_errx(1, "Can't make pipe. (%s)", strerror(errno)); 559 pid = fork(); 560 if (pid == -1) 561 rshd_errx(1, "Can't fork. (%s)", strerror(errno)); 562 if (pid) { 563 { 564 (void) close(0); 565 (void) close(1); 566 } 567 (void) close(2); 568 (void) close(pv[1]); 569 570 set[0].fd = s; 571 set[0].events = POLLIN; 572 set[1].fd = pv[0]; 573 set[1].events = POLLIN; 574 ioctl(pv[0], FIONBIO, (char *)&one); 575 576 /* should set s nbio! */ 577 do { 578 if (poll(set, 2, INFTIM) < 0) 579 break; 580 if (set[0].revents & POLLIN) { 581 int ret; 582 583 ret = read(s, &sig, 1); 584 if (ret <= 0) 585 set[0].events = 0; 586 else 587 killpg(pid, sig); 588 } 589 if (set[1].revents & POLLIN) { 590 errno = 0; 591 cc = read(pv[0], buf, sizeof(buf)); 592 if (cc <= 0) { 593 shutdown(s, SHUT_RDWR); 594 set[1].events = 0; 595 } else { 596 (void) write(s, buf, cc); 597 } 598 } 599 600 } while ((set[0].revents | set[1].revents) & POLLIN); 601 PAM_END; 602 exit(0); 603 } 604 (void) close(s); 605 (void) close(pv[0]); 606 dup2(pv[1], 2); 607 close(pv[1]); 608 } 609 #ifdef USE_PAM 610 else { 611 pid = fork(); 612 if (pid == -1) 613 rshd_errx(1, "Can't fork. (%s)", strerror(errno)); 614 if (pid) { 615 pid_t xpid; 616 int status; 617 if ((xpid = waitpid(pid, &status, 0)) != pid) { 618 pam_err = pam_close_session(pamh, 0); 619 if (pam_err != PAM_SUCCESS) { 620 syslog(LOG_ERR, 621 "pam_close_session: %s", 622 pam_strerror(pamh, pam_err)); 623 } 624 PAM_END; 625 if (xpid != -1) 626 syslog(LOG_WARNING, 627 "wrong PID: %d != %d", pid, xpid); 628 else 629 syslog(LOG_WARNING, 630 "wait pid=%d failed %m", pid); 631 exit(1); 632 } 633 } 634 } 635 #endif 636 637 #ifdef F_CLOSEM 638 (void)fcntl(3, F_CLOSEM, 0); 639 #else 640 for (fd = getdtablesize(); fd > 2; fd--) 641 (void)close(fd); 642 #endif 643 if (setsid() == -1) 644 syslog(LOG_ERR, "setsid() failed: %m"); 645 #ifdef USE_PAM 646 if (setlogin(pwd->pw_name) < 0) 647 syslog(LOG_ERR, "setlogin() failed: %m"); 648 649 if (*pwd->pw_shell == '\0') 650 pwd->pw_shell = _PATH_BSHELL; 651 652 (void)pam_setenv(pamh, "HOME", pwd->pw_dir, 1); 653 (void)pam_setenv(pamh, "SHELL", pwd->pw_shell, 1); 654 (void)pam_setenv(pamh, "USER", pwd->pw_name, 1); 655 (void)pam_setenv(pamh, "PATH", _PATH_DEFPATH, 1); 656 environ = pam_getenvlist(pamh); 657 (void)pam_end(pamh, pam_err); 658 #else 659 #ifdef LOGIN_CAP 660 { 661 char *sh; 662 if ((sh = login_getcapstr(lc, "shell", NULL, NULL))) { 663 if(!(sh = strdup(sh))) { 664 syslog(LOG_ERR, "Cannot alloc mem"); 665 exit(1); 666 } 667 pwd->pw_shell = sh; 668 } 669 } 670 #endif 671 environ = envinit; 672 strlcat(homedir, pwd->pw_dir, sizeof(homedir)); 673 strlcat(path, _PATH_DEFPATH, sizeof(path)); 674 strlcat(shell, pwd->pw_shell, sizeof(shell)); 675 strlcat(username, pwd->pw_name, sizeof(username)); 676 #endif 677 678 cp = strrchr(pwd->pw_shell, '/'); 679 if (cp) 680 cp++; 681 else 682 cp = pwd->pw_shell; 683 684 #ifdef LOGIN_CAP 685 if (setusercontext(lc, pwd, pwd->pw_uid, 686 LOGIN_SETALL & ~LOGIN_SETGROUP) < 0) { 687 syslog(LOG_ERR, "setusercontext(): %m"); 688 exit(1); 689 } 690 login_close(lc); 691 #else 692 (void)setgid((gid_t)pwd->pw_gid); 693 (void)setuid((uid_t)pwd->pw_uid); 694 #endif 695 endpwent(); 696 if (log_success || pwd->pw_uid == 0) { 697 syslog(LOG_INFO|LOG_AUTH, "%s@%s as %s: cmd='%.80s'", 698 remuser, hostname, locuser, cmdbuf); 699 } 700 execl(pwd->pw_shell, cp, "-c", cmdbuf, NULL); 701 rshd_errx(1, "%s: %s", pwd->pw_shell, strerror(errno)); 702 badlogin: 703 syslog(LOG_INFO|LOG_AUTH, 704 "%s@%s as %s: permission denied (%s). cmd='%.80s'", 705 remuser, hostname, locuser, errormsg, cmdbuf); 706 rshd_errx(1, errorstr, errorhost); 707 } 708 709 /* 710 * Report error to client. Note: can't be used until second socket has 711 * connected to client, or older clients will hang waiting for that 712 * connection first. 713 */ 714 715 #include <stdarg.h> 716 717 void 718 rshd_errx(int error, const char *fmt, ...) 719 { 720 va_list ap; 721 int len, rv; 722 char *bp, buf[BUFSIZ]; 723 va_start(ap, fmt); 724 bp = buf; 725 if (sent_null == 0) { 726 *bp++ = 1; 727 len = 1; 728 } else 729 len = 0; 730 rv = vsnprintf(bp, sizeof(buf) - 2, fmt, ap); 731 bp[rv++] = '\n'; 732 (void)write(STDERR_FILENO, buf, len + rv); 733 va_end(ap); 734 exit(error); 735 } 736 737 void 738 getstr(char *buf, int cnt, char *err) 739 { 740 char c; 741 742 do { 743 if (read(STDIN_FILENO, &c, 1) != 1) 744 exit(1); 745 *buf++ = c; 746 if (--cnt == 0) 747 rshd_errx(1, "%s too long", err); 748 } while (c != 0); 749 } 750 751 /* 752 * Check whether host h is in our local domain, 753 * defined as sharing the last two components of the domain part, 754 * or the entire domain part if the local domain has only one component. 755 * If either name is unqualified (contains no '.'), 756 * assume that the host is local, as it will be 757 * interpreted as such. 758 */ 759 int 760 local_domain(char *h) 761 { 762 char localhost[MAXHOSTNAMELEN + 1]; 763 char *p1, *p2; 764 765 localhost[0] = 0; 766 (void)gethostname(localhost, sizeof(localhost)); 767 localhost[sizeof(localhost) - 1] = '\0'; 768 p1 = topdomain(localhost); 769 p2 = topdomain(h); 770 if (p1 == NULL || p2 == NULL || !strcasecmp(p1, p2)) 771 return (1); 772 return (0); 773 } 774 775 char * 776 topdomain(char *h) 777 { 778 char *p, *maybe = NULL; 779 int dots = 0; 780 781 for (p = h + strlen(h); p >= h; p--) { 782 if (*p == '.') { 783 if (++dots == 2) 784 return (p); 785 maybe = p; 786 } 787 } 788 return (maybe); 789 } 790 791 void 792 usage(void) 793 { 794 795 syslog(LOG_ERR, "usage: rshd [-%s]", OPTIONS); 796 exit(2); 797 } 798
Indexes created Sat Sep 27 22:09:54 GMT 2025