rshd.c revision 1.41
1 /* $NetBSD: rshd.c,v 1.41 2005/03/27 21:00:58 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 1.41 2005/03/27 21:00:58 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 *) __attribute__((__noreturn__)); 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, 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(STDIN_FILENO, (struct sockaddr *)&from, &fromlen) < 0) { 190 syslog(LOG_ERR, "getpeername: %m"); 191 return EXIT_FAILURE; 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 (void)memset(&sin, 0, sizeof(sin)); 204 sin.sin_family = AF_INET; 205 sin.sin_len = sizeof(struct sockaddr_in); 206 (void)memcpy(&sin.sin_addr, &sin6->sin6_addr.s6_addr[off], 207 sizeof(sin.sin_addr)); 208 (void)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 return EXIT_FAILURE; 222 } 223 #endif 224 if (keepalive && 225 setsockopt(STDIN_FILENO, 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(STDIN_FILENO, SOL_SOCKET, SO_LINGER, (char *)&linger, 231 sizeof (linger)) < 0) 232 syslog(LOG_WARNING, "setsockopt (SO_LINGER): %m"); 233 proto = getprotobyname("tcp"); 234 (void)setsockopt(STDIN_FILENO, proto->p_proto, TCP_NODELAY, &on, 235 sizeof(on)); 236 doit((struct sockaddr *)&from); 237 } 238 239 char username[20] = "USER="; 240 char homedir[64] = "HOME="; 241 char shell[64] = "SHELL="; 242 char path[100] = "PATH="; 243 char *envinit[] = 244 {homedir, shell, path, username, 0}; 245 char **environ; 246 247 void 248 doit(struct sockaddr *fromp) 249 { 250 struct passwd *pwd; 251 in_port_t port; 252 struct pollfd set[2]; 253 int cc, pv[2], pid, s = -1; /* XXX gcc */ 254 int one = 1; 255 char *hostname, *errorhost = NULL; /* XXX gcc */ 256 const char *cp; 257 char sig, buf[BUFSIZ]; 258 char cmdbuf[NCARGS+1], locuser[16], remuser[16]; 259 char remotehost[2 * MAXHOSTNAMELEN + 1]; 260 char hostnamebuf[2 * MAXHOSTNAMELEN + 1]; 261 #ifdef LOGIN_CAP 262 login_cap_t *lc; 263 #endif 264 char naddr[NI_MAXHOST]; 265 char saddr[NI_MAXHOST]; 266 char raddr[NI_MAXHOST]; 267 char pbuf[NI_MAXSERV]; 268 int af = fromp->sa_family; 269 u_int16_t *portp; 270 struct addrinfo hints, *res, *res0; 271 int gaierror; 272 const int niflags = NI_NUMERICHOST | NI_NUMERICSERV; 273 const char *errormsg = NULL, *errorstr = NULL; 274 275 (void)signal(SIGINT, SIG_DFL); 276 (void)signal(SIGQUIT, SIG_DFL); 277 (void)signal(SIGTERM, SIG_DFL); 278 #ifdef DEBUG 279 { 280 int t = open(_PATH_TTY, O_RDWR); 281 if (t >= 0) { 282 ioctl(t, TIOCNOTTY, NULL); 283 (void)close(t); 284 } 285 } 286 #endif 287 switch (af) { 288 case AF_INET: 289 portp = &((struct sockaddr_in *)fromp)->sin_port; 290 break; 291 #ifdef INET6 292 case AF_INET6: 293 portp = &((struct sockaddr_in6 *)fromp)->sin6_port; 294 break; 295 #endif 296 default: 297 syslog(LOG_ERR, "malformed \"from\" address (af %d)", af); 298 exit(EXIT_FAILURE); 299 } 300 if (getnameinfo(fromp, fromp->sa_len, naddr, sizeof(naddr), 301 pbuf, sizeof(pbuf), niflags) != 0) { 302 syslog(LOG_ERR, "malformed \"from\" address (af %d)", af); 303 exit(EXIT_FAILURE); 304 } 305 #ifdef IP_OPTIONS 306 if (af == AF_INET) { 307 308 u_char optbuf[BUFSIZ/3]; 309 int optsize = sizeof(optbuf), ipproto, i; 310 struct protoent *ip; 311 312 if ((ip = getprotobyname("ip")) != NULL) 313 ipproto = ip->p_proto; 314 else 315 ipproto = IPPROTO_IP; 316 if (!getsockopt(0, ipproto, IP_OPTIONS, (char *)optbuf, &optsize) && 317 optsize != 0) { 318 for (i = 0; i < optsize;) { 319 u_char c = optbuf[i]; 320 if (c == IPOPT_LSRR || c == IPOPT_SSRR) { 321 syslog(LOG_NOTICE, 322 "Connection refused from %s " 323 "with IP option %s", 324 inet_ntoa(( 325 (struct sockaddr_in *)fromp)->sin_addr), 326 c == IPOPT_LSRR ? "LSRR" : "SSRR"); 327 exit(EXIT_FAILURE); 328 } 329 if (c == IPOPT_EOL) 330 break; 331 i += (c == IPOPT_NOP) ? 1 : optbuf[i + 1]; 332 } 333 } 334 } 335 #endif 336 if (ntohs(*portp) >= IPPORT_RESERVED 337 || ntohs(*portp) < IPPORT_RESERVED / 2) { 338 syslog(LOG_NOTICE|LOG_AUTH, 339 "Connection from %s on illegal port %u", 340 naddr, ntohs(*portp)); 341 exit(EXIT_FAILURE); 342 } 343 344 (void) alarm(60); 345 port = 0; 346 for (;;) { 347 char c; 348 349 if ((cc = read(STDIN_FILENO, &c, 1)) != 1) { 350 if (cc < 0) 351 syslog(LOG_ERR, "read: %m"); 352 (void)shutdown(0, SHUT_RDWR); 353 exit(EXIT_FAILURE); 354 } 355 if (c == 0) 356 break; 357 port = port * 10 + c - '0'; 358 } 359 360 (void) alarm(0); 361 if (port != 0) { 362 int lport = IPPORT_RESERVED - 1; 363 s = rresvport_af(&lport, af); 364 if (s < 0) { 365 syslog(LOG_ERR, "can't get stderr port: %m"); 366 exit(EXIT_FAILURE); 367 } 368 if (port >= IPPORT_RESERVED) { 369 syslog(LOG_ERR, "2nd port not reserved"); 370 exit(EXIT_FAILURE); 371 } 372 *portp = htons(port); 373 if (connect(s, fromp, fromp->sa_len) < 0) { 374 syslog(LOG_ERR, "connect second port %d: %m", port); 375 exit(EXIT_FAILURE); 376 } 377 } 378 379 380 #ifdef notdef 381 /* from inetd, socket is already on 0, 1, 2 */ 382 (void)dup2(f, STDIN_FILENO); 383 (void)dup2(f, STDOUT_FILENO); 384 (void)dup2(f, STDERR_FILENO); 385 #endif 386 if (getnameinfo(fromp, fromp->sa_len, saddr, sizeof(saddr), 387 NULL, 0, NI_NAMEREQD) == 0) { 388 /* 389 * If name returned by getnameinfo is in our domain, 390 * attempt to verify that we haven't been fooled by someone 391 * in a remote net; look up the name and check that this 392 * address corresponds to the name. 393 */ 394 hostname = saddr; 395 res0 = NULL; 396 if (check_all || local_domain(saddr)) { 397 (void)strlcpy(remotehost, saddr, sizeof(remotehost)); 398 errorhost = remotehost; 399 (void)memset(&hints, 0, sizeof(hints)); 400 hints.ai_family = fromp->sa_family; 401 hints.ai_socktype = SOCK_STREAM; 402 hints.ai_flags = AI_CANONNAME; 403 gaierror = getaddrinfo(remotehost, pbuf, &hints, &res0); 404 if (gaierror) { 405 syslog(LOG_NOTICE, 406 "Couldn't look up address for %s: %s", 407 remotehost, gai_strerror(gaierror)); 408 errorstr = 409 "Couldn't look up address for your host (%s)\n"; 410 hostname = naddr; 411 } else { 412 for (res = res0; res; res = res->ai_next) { 413 if (res->ai_family != fromp->sa_family) 414 continue; 415 if (res->ai_addrlen != fromp->sa_len) 416 continue; 417 if (getnameinfo(res->ai_addr, 418 res->ai_addrlen, 419 raddr, sizeof(raddr), NULL, 0, 420 niflags) == 0 421 && strcmp(naddr, raddr) == 0) { 422 hostname = res->ai_canonname 423 ? res->ai_canonname 424 : saddr; 425 break; 426 } 427 } 428 if (res == NULL) { 429 syslog(LOG_NOTICE, 430 "Host addr %s not listed for host %s", 431 naddr, res0->ai_canonname 432 ? res0->ai_canonname 433 : saddr); 434 errorstr = 435 "Host address mismatch for %s\n"; 436 hostname = naddr; 437 } 438 } 439 } 440 (void)strlcpy(hostnamebuf, hostname, sizeof(hostnamebuf)); 441 hostname = hostnamebuf; 442 if (res0) 443 freeaddrinfo(res0); 444 } else { 445 (void)strlcpy(hostnamebuf, naddr, sizeof(hostnamebuf)); 446 errorhost = hostname = hostnamebuf; 447 } 448 449 (void)alarm(60); 450 getstr(remuser, sizeof(remuser), "remuser"); 451 getstr(locuser, sizeof(locuser), "locuser"); 452 getstr(cmdbuf, sizeof(cmdbuf), "command"); 453 (void)alarm(0); 454 455 #ifdef USE_PAM 456 pam_err = pam_start("rsh", locuser, &pamc, &pamh); 457 if (pam_err != PAM_SUCCESS) { 458 syslog(LOG_ERR|LOG_AUTH, "pam_start(): %s", 459 pam_strerror(pamh, pam_err)); 460 rshd_errx(EXIT_FAILURE, incorrect); 461 } 462 463 if ((pam_err = pam_set_item(pamh, PAM_RUSER, remuser)) != PAM_SUCCESS || 464 (pam_err = pam_set_item(pamh, PAM_RHOST, hostname) != PAM_SUCCESS)){ 465 syslog(LOG_ERR|LOG_AUTH, "pam_set_item(): %s", 466 pam_strerror(pamh, pam_err)); 467 rshd_errx(EXIT_FAILURE, incorrect); 468 } 469 470 pam_err = pam_authenticate(pamh, 0); 471 if (pam_err == PAM_SUCCESS) { 472 if ((pam_err = pam_get_user(pamh, &cp, NULL)) == PAM_SUCCESS) { 473 (void)strlcpy(locuser, cp, sizeof(locuser)); 474 /* XXX truncation! */ 475 } 476 pam_err = pam_acct_mgmt(pamh, 0); 477 } 478 if (pam_err != PAM_SUCCESS) { 479 errorstr = incorrect; 480 errormsg = pam_strerror(pamh, pam_err); 481 goto badlogin; 482 } 483 #endif /* USE_PAM */ 484 setpwent(); 485 pwd = getpwnam(locuser); 486 if (pwd == NULL) { 487 syslog(LOG_INFO|LOG_AUTH, 488 "%s@%s as %s: unknown login. cmd='%.80s'", 489 remuser, hostname, locuser, cmdbuf); 490 if (errorstr == NULL) 491 errorstr = "Permission denied."; 492 rshd_errx(EXIT_FAILURE, errorstr, errorhost); 493 } 494 #ifdef LOGIN_CAP 495 lc = login_getclass(pwd ? pwd->pw_class : NULL); 496 #endif 497 498 if (chdir(pwd->pw_dir) < 0) { 499 if (chdir("/") < 0 500 #ifdef LOGIN_CAP 501 || login_getcapbool(lc, "requirehome", pwd->pw_uid ? 1 : 0) 502 #endif 503 ) { 504 syslog(LOG_INFO|LOG_AUTH, 505 "%s@%s as %s: no home directory. cmd='%.80s'", 506 remuser, hostname, locuser, cmdbuf); 507 rshd_errx(EXIT_SUCCESS, "No remote home directory."); 508 } 509 } 510 511 #ifndef USE_PAM 512 if (errorstr || 513 (pwd->pw_passwd != 0 && *pwd->pw_passwd != '\0' && 514 iruserok_sa(fromp, fromp->sa_len, pwd->pw_uid == 0, remuser, 515 locuser) < 0)) { 516 errormsg = __rcmd_errstr ? __rcmd_errstr : "unknown error"; 517 if (errorstr == NULL) 518 errorstr = "Permission denied."; 519 goto badlogin; 520 } 521 522 if (pwd->pw_uid && !access(_PATH_NOLOGIN, F_OK)) 523 rshd_errx(EXIT_FAILURE, "Logins currently disabled."); 524 #endif 525 526 #ifdef LOGIN_CAP 527 /* 528 * PAM modules might add supplementary groups in 529 * pam_setcred(), so initialize them first. 530 * But we need to open the session as root. 531 */ 532 if (setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETGROUP) != 0) { 533 syslog(LOG_ERR, "setusercontext: %m"); 534 exit(EXIT_FAILURE); 535 } 536 #else 537 initgroups(pwd->pw_name, pwd->pw_gid); 538 #endif 539 540 #ifdef USE_PAM 541 if ((pam_err = pam_open_session(pamh, 0)) != PAM_SUCCESS) { 542 syslog(LOG_ERR, "pam_open_session: %s", 543 pam_strerror(pamh, pam_err)); 544 } else if ((pam_err = pam_setcred(pamh, PAM_ESTABLISH_CRED)) 545 != PAM_SUCCESS) { 546 syslog(LOG_ERR, "pam_setcred: %s", pam_strerror(pamh, pam_err)); 547 } 548 #endif 549 550 (void)write(STDERR_FILENO, "\0", 1); 551 sent_null = 1; 552 553 if (port) { 554 if (pipe(pv) < 0) 555 rshd_errx(EXIT_FAILURE, "Can't make pipe. (%s)", 556 strerror(errno)); 557 pid = fork(); 558 if (pid == -1) 559 rshd_errx(EXIT_FAILURE, "Can't fork. (%s)", 560 strerror(errno)); 561 if (pid) { 562 (void)close(STDIN_FILENO); 563 (void)close(STDOUT_FILENO); 564 (void)close(STDERR_FILENO); 565 (void)close(pv[1]); 566 567 set[0].fd = s; 568 set[0].events = POLLIN; 569 set[1].fd = pv[0]; 570 set[1].events = POLLIN; 571 ioctl(pv[0], FIONBIO, (char *)&one); 572 573 /* should set s nbio! */ 574 do { 575 if (poll(set, 2, INFTIM) < 0) 576 break; 577 if (set[0].revents & POLLIN) { 578 int ret; 579 580 ret = read(s, &sig, 1); 581 if (ret <= 0) 582 set[0].events = 0; 583 else 584 killpg(pid, sig); 585 } 586 if (set[1].revents & POLLIN) { 587 errno = 0; 588 cc = read(pv[0], buf, sizeof(buf)); 589 if (cc <= 0) { 590 shutdown(s, SHUT_RDWR); 591 set[1].events = 0; 592 } else { 593 (void)write(s, buf, cc); 594 } 595 } 596 597 } while ((set[0].revents | set[1].revents) & POLLIN); 598 PAM_END; 599 exit(EXIT_SUCCESS); 600 } 601 (void)close(s); 602 (void)close(pv[0]); 603 (void)dup2(pv[1], STDERR_FILENO); 604 close(pv[1]); 605 } 606 #ifdef USE_PAM 607 else { 608 pid = fork(); 609 if (pid == -1) 610 rshd_errx(EXIT_FAILURE, "Can't fork. (%s)", 611 strerror(errno)); 612 if (pid) { 613 pid_t xpid; 614 int status; 615 if ((xpid = waitpid(pid, &status, 0)) != pid) { 616 pam_err = pam_close_session(pamh, 0); 617 if (pam_err != PAM_SUCCESS) { 618 syslog(LOG_ERR, 619 "pam_close_session: %s", 620 pam_strerror(pamh, pam_err)); 621 } 622 PAM_END; 623 if (xpid != -1) 624 syslog(LOG_WARNING, 625 "wrong PID: %d != %d", pid, xpid); 626 else 627 syslog(LOG_WARNING, 628 "wait pid=%d failed %m", pid); 629 exit(EXIT_FAILURE); 630 } 631 exit(EXIT_SUCCESS); 632 } 633 } 634 #endif 635 636 #ifdef F_CLOSEM 637 (void)fcntl(STDERR_FILENO + 1, F_CLOSEM, 0); 638 #else 639 for (fd = getdtablesize(); fd > STDERR_FILENO; fd--) 640 (void)close(fd); 641 #endif 642 if (setsid() == -1) 643 syslog(LOG_ERR, "setsid() failed: %m"); 644 #ifdef USE_PAM 645 if (setlogin(pwd->pw_name) < 0) 646 syslog(LOG_ERR, "setlogin() failed: %m"); 647 648 if (*pwd->pw_shell == '\0') 649 pwd->pw_shell = __UNCONST(_PATH_BSHELL); 650 651 (void)pam_setenv(pamh, "HOME", pwd->pw_dir, 1); 652 (void)pam_setenv(pamh, "SHELL", pwd->pw_shell, 1); 653 (void)pam_setenv(pamh, "USER", pwd->pw_name, 1); 654 (void)pam_setenv(pamh, "PATH", _PATH_DEFPATH, 1); 655 environ = pam_getenvlist(pamh); 656 (void)pam_end(pamh, pam_err); 657 #else 658 #ifdef LOGIN_CAP 659 { 660 char *sh; 661 if ((sh = login_getcapstr(lc, "shell", NULL, NULL))) { 662 if(!(sh = strdup(sh))) { 663 syslog(LOG_ERR, "Cannot alloc mem"); 664 exit(EXIT_FAILURE); 665 } 666 pwd->pw_shell = sh; 667 } 668 } 669 #endif 670 environ = envinit; 671 (void)strlcat(homedir, pwd->pw_dir, sizeof(homedir)); 672 (void)strlcat(path, _PATH_DEFPATH, sizeof(path)); 673 (void)strlcat(shell, pwd->pw_shell, sizeof(shell)); 674 (void)strlcat(username, pwd->pw_name, sizeof(username)); 675 #endif 676 677 cp = strrchr(pwd->pw_shell, '/'); 678 if (cp) 679 cp++; 680 else 681 cp = pwd->pw_shell; 682 683 #ifdef LOGIN_CAP 684 if (setusercontext(lc, pwd, pwd->pw_uid, 685 LOGIN_SETALL & ~LOGIN_SETGROUP) < 0) { 686 syslog(LOG_ERR, "setusercontext(): %m"); 687 exit(EXIT_FAILURE); 688 } 689 login_close(lc); 690 #else 691 (void)setgid((gid_t)pwd->pw_gid); 692 (void)setuid((uid_t)pwd->pw_uid); 693 #endif 694 endpwent(); 695 if (log_success || pwd->pw_uid == 0) { 696 syslog(LOG_INFO|LOG_AUTH, "%s@%s as %s: cmd='%.80s'", 697 remuser, hostname, locuser, cmdbuf); 698 } 699 (void)execl(pwd->pw_shell, cp, "-c", cmdbuf, NULL); 700 rshd_errx(EXIT_FAILURE, "%s: %s", pwd->pw_shell, strerror(errno)); 701 badlogin: 702 syslog(LOG_INFO|LOG_AUTH, 703 "%s@%s as %s: permission denied (%s). cmd='%.80s'", 704 remuser, hostname, locuser, errormsg, cmdbuf); 705 rshd_errx(EXIT_FAILURE, errorstr, errorhost); 706 } 707 708 /* 709 * Report error to client. Note: can't be used until second socket has 710 * connected to client, or older clients will hang waiting for that 711 * connection first. 712 */ 713 714 #include <stdarg.h> 715 716 void 717 rshd_errx(int error, const char *fmt, ...) 718 { 719 va_list ap; 720 int len, rv; 721 char *bp, buf[BUFSIZ]; 722 va_start(ap, fmt); 723 bp = buf; 724 if (sent_null == 0) { 725 *bp++ = 1; 726 len = 1; 727 } else 728 len = 0; 729 rv = vsnprintf(bp, sizeof(buf) - 2, fmt, ap); 730 bp[rv++] = '\n'; 731 (void)write(STDERR_FILENO, buf, len + rv); 732 va_end(ap); 733 exit(error); 734 } 735 736 void 737 getstr(char *buf, int cnt, const char *err) 738 { 739 char c; 740 741 do { 742 if (read(STDIN_FILENO, &c, 1) != 1) 743 exit(EXIT_FAILURE); 744 *buf++ = c; 745 if (--cnt == 0) 746 rshd_errx(EXIT_FAILURE, "%s too long", err); 747 } while (c != 0); 748 } 749 750 /* 751 * Check whether host h is in our local domain, 752 * defined as sharing the last two components of the domain part, 753 * or the entire domain part if the local domain has only one component. 754 * If either name is unqualified (contains no '.'), 755 * assume that the host is local, as it will be 756 * interpreted as such. 757 */ 758 int 759 local_domain(char *h) 760 { 761 char localhost[MAXHOSTNAMELEN + 1]; 762 char *p1, *p2; 763 764 localhost[0] = 0; 765 (void)gethostname(localhost, sizeof(localhost)); 766 localhost[sizeof(localhost) - 1] = '\0'; 767 p1 = topdomain(localhost); 768 p2 = topdomain(h); 769 if (p1 == NULL || p2 == NULL || !strcasecmp(p1, p2)) 770 return (1); 771 return (0); 772 } 773 774 char * 775 topdomain(char *h) 776 { 777 char *p, *maybe = NULL; 778 int dots = 0; 779 780 for (p = h + strlen(h); p >= h; p--) { 781 if (*p == '.') { 782 if (++dots == 2) 783 return (p); 784 maybe = p; 785 } 786 } 787 return (maybe); 788 } 789 790 void 791 usage(void) 792 { 793 794 syslog(LOG_ERR, "Usage: %s [-%s]", getprogname(), OPTIONS); 795 exit(EXIT_FAILURE); 796 } 797
Indexes created Tue Sep 23 14:10:03 GMT 2025