1 /* $NetBSD: rshd.c,v 1.51 2017/10/07 19:23:02 ryo 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 1.51 2017/10/07 19:23:02 ryo 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 static int keepalive = 1; 136 static int check_all; 137 static int log_success; /* If TRUE, log all successful accesses */ 138 static int sent_null; 139 140 __dead static void doit(struct sockaddr *, struct sockaddr *); 141 __dead static void rshd_errx(int, const char *, ...) __printflike(2, 3); 142 static void getstr(char *, int, const char *); 143 static int local_domain(char *); 144 static char *topdomain(char *); 145 __dead static void usage(void); 146 147 #define OPTIONS "aLln" 148 extern int __check_rhosts_file; 149 extern char *__rcmd_errstr; /* syslog hook from libc/net/rcmd.c. */ 150 #ifdef USE_PAM 151 static const char incorrect[] = "Login incorrect."; 152 #endif 153 154 int 155 main(int argc, char *argv[]) 156 { 157 struct linger linger; 158 int ch, on = 1; 159 socklen_t fromlen; 160 socklen_t locallen; 161 struct sockaddr_storage from; 162 struct sockaddr_storage local; 163 struct protoent *proto; 164 165 openlog("rshd", LOG_PID, LOG_DAEMON); 166 167 opterr = 0; 168 while ((ch = getopt(argc, argv, OPTIONS)) != -1) 169 switch (ch) { 170 case 'a': 171 check_all = 1; 172 break; 173 case 'l': 174 __check_rhosts_file = 0; 175 break; 176 case 'n': 177 keepalive = 0; 178 break; 179 case 'L': 180 log_success = 1; 181 break; 182 case '?': 183 default: 184 usage(); 185 break; 186 } 187 188 argc -= optind; 189 argv += optind; 190 191 fromlen = sizeof(from); /* xxx */ 192 locallen = sizeof(local); /* xxx */ 193 if (getpeername(STDIN_FILENO, (struct sockaddr *)&from, &fromlen) < 0) { 194 syslog(LOG_ERR, "getpeername: %m"); 195 return EXIT_FAILURE; 196 } 197 if (getsockname(STDIN_FILENO, (struct sockaddr *)&local, 198 &locallen) < 0) { 199 syslog(LOG_ERR, "getsockname: %m"); 200 return EXIT_FAILURE; 201 } 202 #if 0 203 if (((struct sockaddr *)&from)->sa_family == AF_INET6 && 204 IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&from)->sin6_addr) && 205 sizeof(struct sockaddr_in) <= sizeof(from)) { 206 struct sockaddr_in sin; 207 struct sockaddr_in6 *sin6; 208 const int off = sizeof(struct sockaddr_in6) - 209 sizeof(struct sockaddr_in); 210 211 sin6 = (struct sockaddr_in6 *)&from; 212 (void)memset(&sin, 0, sizeof(sin)); 213 sin.sin_family = AF_INET; 214 sin.sin_len = sizeof(struct sockaddr_in); 215 (void)memcpy(&sin.sin_addr, &sin6->sin6_addr.s6_addr[off], 216 sizeof(sin.sin_addr)); 217 (void)memcpy(&from, &sin, sizeof(sin)); 218 fromlen = sin.sin_len; 219 } 220 #else 221 if (((struct sockaddr *)&from)->sa_family == AF_INET6 && 222 IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&from)->sin6_addr)) { 223 char hbuf[NI_MAXHOST]; 224 if (getnameinfo((struct sockaddr *)&from, fromlen, hbuf, 225 sizeof(hbuf), NULL, 0, NI_NUMERICHOST) != 0) { 226 strlcpy(hbuf, "invalid", sizeof(hbuf)); 227 } 228 syslog(LOG_ERR, "malformed \"from\" address (v4 mapped, %s)", 229 hbuf); 230 return EXIT_FAILURE; 231 } 232 #endif 233 if (keepalive && 234 setsockopt(STDIN_FILENO, SOL_SOCKET, SO_KEEPALIVE, (char *)&on, 235 sizeof(on)) < 0) 236 syslog(LOG_WARNING, "setsockopt (SO_KEEPALIVE): %m"); 237 linger.l_onoff = 1; 238 linger.l_linger = 60; /* XXX */ 239 if (setsockopt(STDIN_FILENO, SOL_SOCKET, SO_LINGER, (char *)&linger, 240 sizeof (linger)) < 0) 241 syslog(LOG_WARNING, "setsockopt (SO_LINGER): %m"); 242 proto = getprotobyname("tcp"); 243 (void)setsockopt(STDIN_FILENO, proto->p_proto, TCP_NODELAY, &on, 244 sizeof(on)); 245 doit((struct sockaddr *)&from, (struct sockaddr *)&local); 246 } 247 248 extern char **environ; 249 250 static void 251 doit(struct sockaddr *fromp, struct sockaddr *localp) 252 { 253 struct passwd *pwd, pwres; 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 char pwbuf[1024]; 278 279 (void)signal(SIGINT, SIG_DFL); 280 (void)signal(SIGQUIT, SIG_DFL); 281 (void)signal(SIGTERM, SIG_DFL); 282 #ifdef DEBUG 283 { 284 int t = open(_PATH_TTY, O_RDWR); 285 if (t >= 0) { 286 ioctl(t, TIOCNOTTY, NULL); 287 (void)close(t); 288 } 289 } 290 #endif 291 switch (af) { 292 case AF_INET: 293 portp = &((struct sockaddr_in *)fromp)->sin_port; 294 break; 295 #ifdef INET6 296 case AF_INET6: 297 portp = &((struct sockaddr_in6 *)fromp)->sin6_port; 298 break; 299 #endif 300 default: 301 syslog(LOG_ERR, "malformed \"from\" address (af %d)", af); 302 exit(EXIT_FAILURE); 303 } 304 if (getnameinfo(fromp, fromp->sa_len, naddr, sizeof(naddr), 305 pbuf, sizeof(pbuf), niflags) != 0) { 306 syslog(LOG_ERR, "malformed \"from\" address (af %d)", af); 307 exit(EXIT_FAILURE); 308 } 309 #ifdef IP_OPTIONS 310 if (af == AF_INET) { 311 312 u_char optbuf[BUFSIZ/3]; 313 socklen_t optsize = sizeof(optbuf); 314 int ipproto; 315 unsigned int i; 316 struct protoent *ip; 317 318 if ((ip = getprotobyname("ip")) != NULL) 319 ipproto = ip->p_proto; 320 else 321 ipproto = IPPROTO_IP; 322 if (!getsockopt(0, ipproto, IP_OPTIONS, (char *)optbuf, &optsize) && 323 optsize != 0) { 324 for (i = 0; i < optsize;) { 325 u_char c = optbuf[i]; 326 if (c == IPOPT_LSRR || c == IPOPT_SSRR) { 327 syslog(LOG_NOTICE, 328 "Connection refused from %s " 329 "with IP option %s", 330 inet_ntoa(( 331 (struct sockaddr_in *)fromp)->sin_addr), 332 c == IPOPT_LSRR ? "LSRR" : "SSRR"); 333 exit(EXIT_FAILURE); 334 } 335 if (c == IPOPT_EOL) 336 break; 337 i += (c == IPOPT_NOP) ? 1 : optbuf[i + 1]; 338 } 339 } 340 } 341 #endif 342 if (ntohs(*portp) >= IPPORT_RESERVED 343 || ntohs(*portp) < IPPORT_RESERVED / 2) { 344 syslog(LOG_NOTICE|LOG_AUTH, 345 "Connection from %s on illegal port %u", 346 naddr, ntohs(*portp)); 347 exit(EXIT_FAILURE); 348 } 349 350 (void) alarm(60); 351 port = 0; 352 for (;;) { 353 char c; 354 355 if ((cc = read(STDIN_FILENO, &c, 1)) != 1) { 356 if (cc < 0) 357 syslog(LOG_ERR, "read: %m"); 358 (void)shutdown(0, SHUT_RDWR); 359 exit(EXIT_FAILURE); 360 } 361 if (c == 0) 362 break; 363 port = port * 10 + c - '0'; 364 } 365 366 (void) alarm(0); 367 if (port != 0) { 368 int lport = IPPORT_RESERVED - 1; 369 s = rresvport_af_addr(&lport, af, localp); 370 if (s < 0) { 371 syslog(LOG_ERR, "can't get stderr port: %m"); 372 exit(EXIT_FAILURE); 373 } 374 if (port >= IPPORT_RESERVED) { 375 syslog(LOG_ERR, "2nd port not reserved"); 376 exit(EXIT_FAILURE); 377 } 378 *portp = htons(port); 379 if (connect(s, fromp, fromp->sa_len) < 0) { 380 syslog(LOG_ERR, "connect second port %d: %m", port); 381 exit(EXIT_FAILURE); 382 } 383 } 384 385 386 #ifdef notdef 387 /* from inetd, socket is already on 0, 1, 2 */ 388 (void)dup2(f, STDIN_FILENO); 389 (void)dup2(f, STDOUT_FILENO); 390 (void)dup2(f, STDERR_FILENO); 391 #endif 392 if (getnameinfo(fromp, fromp->sa_len, saddr, sizeof(saddr), 393 NULL, 0, NI_NAMEREQD) == 0) { 394 /* 395 * If name returned by getnameinfo is in our domain, 396 * attempt to verify that we haven't been fooled by someone 397 * in a remote net; look up the name and check that this 398 * address corresponds to the name. 399 */ 400 hostname = saddr; 401 res0 = NULL; 402 if (check_all || local_domain(saddr)) { 403 (void)strlcpy(remotehost, saddr, sizeof(remotehost)); 404 errorhost = remotehost; 405 (void)memset(&hints, 0, sizeof(hints)); 406 hints.ai_family = fromp->sa_family; 407 hints.ai_socktype = SOCK_STREAM; 408 hints.ai_flags = AI_CANONNAME; 409 gaierror = getaddrinfo(remotehost, pbuf, &hints, &res0); 410 if (gaierror) { 411 syslog(LOG_NOTICE, 412 "Couldn't look up address for %s: %s", 413 remotehost, gai_strerror(gaierror)); 414 errorstr = 415 "Couldn't look up address for your host (%s)\n"; 416 hostname = naddr; 417 } else { 418 for (res = res0; res; res = res->ai_next) { 419 if (res->ai_family != fromp->sa_family) 420 continue; 421 if (res->ai_addrlen != fromp->sa_len) 422 continue; 423 if (getnameinfo(res->ai_addr, 424 res->ai_addrlen, 425 raddr, sizeof(raddr), NULL, 0, 426 niflags) == 0 427 && strcmp(naddr, raddr) == 0) { 428 hostname = res->ai_canonname 429 ? res->ai_canonname 430 : saddr; 431 break; 432 } 433 } 434 if (res == NULL) { 435 syslog(LOG_NOTICE, 436 "Host addr %s not listed for host %s", 437 naddr, res0->ai_canonname 438 ? res0->ai_canonname 439 : saddr); 440 errorstr = 441 "Host address mismatch for %s\n"; 442 hostname = naddr; 443 } 444 } 445 } 446 (void)strlcpy(hostnamebuf, hostname, sizeof(hostnamebuf)); 447 hostname = hostnamebuf; 448 if (res0) 449 freeaddrinfo(res0); 450 } else { 451 (void)strlcpy(hostnamebuf, naddr, sizeof(hostnamebuf)); 452 errorhost = hostname = hostnamebuf; 453 } 454 455 (void)alarm(60); 456 getstr(remuser, sizeof(remuser), "remuser"); 457 getstr(locuser, sizeof(locuser), "locuser"); 458 getstr(cmdbuf, sizeof(cmdbuf), "command"); 459 (void)alarm(0); 460 461 #ifdef USE_PAM 462 pam_err = pam_start("rsh", locuser, &pamc, &pamh); 463 if (pam_err != PAM_SUCCESS) { 464 syslog(LOG_ERR|LOG_AUTH, "pam_start(): %s", 465 pam_strerror(pamh, pam_err)); 466 rshd_errx(EXIT_FAILURE, incorrect); 467 } 468 469 if ((pam_err = pam_set_item(pamh, PAM_RUSER, remuser)) != PAM_SUCCESS || 470 (pam_err = pam_set_item(pamh, PAM_RHOST, hostname)) != PAM_SUCCESS){ 471 syslog(LOG_ERR|LOG_AUTH, "pam_set_item(): %s", 472 pam_strerror(pamh, pam_err)); 473 rshd_errx(EXIT_FAILURE, incorrect); 474 } 475 476 pam_err = pam_authenticate(pamh, 0); 477 if (pam_err == PAM_SUCCESS) { 478 if ((pam_err = pam_get_user(pamh, &cp, NULL)) == PAM_SUCCESS) { 479 (void)strlcpy(locuser, cp, sizeof(locuser)); 480 /* XXX truncation! */ 481 } 482 pam_err = pam_acct_mgmt(pamh, 0); 483 } 484 if (pam_err != PAM_SUCCESS) { 485 errorstr = incorrect; 486 errormsg = pam_strerror(pamh, pam_err); 487 goto badlogin; 488 } 489 #endif /* USE_PAM */ 490 setpwent(); 491 if (getpwnam_r(locuser, &pwres, pwbuf, sizeof(pwbuf), &pwd) != 0 || 492 pwd == NULL) { 493 syslog(LOG_INFO|LOG_AUTH, 494 "%s@%s as %s: unknown login. cmd='%.80s'", 495 remuser, hostname, locuser, cmdbuf); 496 if (errorstr == NULL) 497 errorstr = "Permission denied."; 498 rshd_errx(EXIT_FAILURE, errorstr, errorhost); 499 } 500 #ifdef LOGIN_CAP 501 lc = login_getclass(pwd ? pwd->pw_class : NULL); 502 #endif 503 504 if (chdir(pwd->pw_dir) < 0) { 505 if (chdir("/") < 0 506 #ifdef LOGIN_CAP 507 || login_getcapbool(lc, "requirehome", pwd->pw_uid ? 1 : 0) 508 #endif 509 ) { 510 syslog(LOG_INFO|LOG_AUTH, 511 "%s@%s as %s: no home directory. cmd='%.80s'", 512 remuser, hostname, locuser, cmdbuf); 513 rshd_errx(EXIT_SUCCESS, "No remote home directory."); 514 } 515 } 516 517 #ifndef USE_PAM 518 if (errorstr || 519 (pwd->pw_passwd != 0 && *pwd->pw_passwd != '\0' && 520 iruserok_sa(fromp, fromp->sa_len, pwd->pw_uid == 0, remuser, 521 locuser) < 0)) { 522 errormsg = __rcmd_errstr ? __rcmd_errstr : "unknown error"; 523 if (errorstr == NULL) 524 errorstr = "Permission denied."; 525 goto badlogin; 526 } 527 528 if (pwd->pw_uid && !access(_PATH_NOLOGIN, F_OK)) 529 rshd_errx(EXIT_FAILURE, "Logins currently disabled."); 530 #endif 531 532 #ifdef LOGIN_CAP 533 /* 534 * PAM modules might add supplementary groups in 535 * pam_setcred(), so initialize them first. 536 * But we need to open the session as root. 537 */ 538 if (setusercontext(lc, pwd, pwd->pw_uid, LOGIN_SETGROUP) != 0) { 539 syslog(LOG_ERR, "setusercontext: %m"); 540 exit(EXIT_FAILURE); 541 } 542 #else 543 initgroups(pwd->pw_name, pwd->pw_gid); 544 #endif 545 546 #ifdef USE_PAM 547 if ((pam_err = pam_open_session(pamh, 0)) != PAM_SUCCESS) { 548 syslog(LOG_ERR, "pam_open_session: %s", 549 pam_strerror(pamh, pam_err)); 550 } else if ((pam_err = pam_setcred(pamh, PAM_ESTABLISH_CRED)) 551 != PAM_SUCCESS) { 552 syslog(LOG_ERR, "pam_setcred: %s", pam_strerror(pamh, pam_err)); 553 } 554 #endif 555 556 (void)write(STDERR_FILENO, "\0", 1); 557 sent_null = 1; 558 559 if (port) { 560 if (pipe(pv) < 0) 561 rshd_errx(EXIT_FAILURE, "Can't make pipe. (%s)", 562 strerror(errno)); 563 pid = fork(); 564 if (pid == -1) 565 rshd_errx(EXIT_FAILURE, "Can't fork. (%s)", 566 strerror(errno)); 567 if (pid) { 568 (void)close(STDIN_FILENO); 569 (void)close(STDOUT_FILENO); 570 (void)close(STDERR_FILENO); 571 (void)close(pv[1]); 572 573 set[0].fd = s; 574 set[0].events = POLLIN; 575 set[1].fd = pv[0]; 576 set[1].events = POLLIN; 577 ioctl(pv[0], FIONBIO, (char *)&one); 578 579 /* should set s nbio! */ 580 do { 581 if (poll(set, 2, INFTIM) < 0) 582 break; 583 if (set[0].revents & POLLIN) { 584 int ret; 585 586 ret = read(s, &sig, 1); 587 if (ret <= 0) 588 set[0].events = 0; 589 else 590 killpg(pid, sig); 591 } 592 if (set[1].revents & POLLIN) { 593 errno = 0; 594 cc = read(pv[0], buf, sizeof(buf)); 595 if (cc <= 0) { 596 shutdown(s, SHUT_RDWR); 597 set[1].events = 0; 598 } else { 599 (void)write(s, buf, cc); 600 } 601 } 602 603 } while ((set[0].revents | set[1].revents) & POLLIN); 604 PAM_END; 605 exit(EXIT_SUCCESS); 606 } 607 (void)close(s); 608 (void)close(pv[0]); 609 (void)dup2(pv[1], STDERR_FILENO); 610 close(pv[1]); 611 } 612 #ifdef USE_PAM 613 else { 614 pid = fork(); 615 if (pid == -1) 616 rshd_errx(EXIT_FAILURE, "Can't fork. (%s)", 617 strerror(errno)); 618 if (pid) { 619 pid_t xpid; 620 int status; 621 if ((xpid = waitpid(pid, &status, 0)) != pid) { 622 pam_err = pam_close_session(pamh, 0); 623 if (pam_err != PAM_SUCCESS) { 624 syslog(LOG_ERR, 625 "pam_close_session: %s", 626 pam_strerror(pamh, pam_err)); 627 } 628 PAM_END; 629 if (xpid != -1) 630 syslog(LOG_WARNING, 631 "wrong PID: %d != %d", pid, xpid); 632 else 633 syslog(LOG_WARNING, 634 "wait pid=%d failed %m", pid); 635 exit(EXIT_FAILURE); 636 } 637 exit(EXIT_SUCCESS); 638 } 639 } 640 #endif 641 642 #ifdef F_CLOSEM 643 (void)fcntl(STDERR_FILENO + 1, F_CLOSEM, 0); 644 #else 645 for (fd = getdtablesize(); fd > STDERR_FILENO; fd--) 646 (void)close(fd); 647 #endif 648 if (setsid() == -1) 649 syslog(LOG_ERR, "setsid() failed: %m"); 650 #ifdef USE_PAM 651 if (setlogin(pwd->pw_name) < 0) 652 syslog(LOG_ERR, "setlogin() failed: %m"); 653 654 if (*pwd->pw_shell == '\0') 655 pwd->pw_shell = __UNCONST(_PATH_BSHELL); 656 657 (void)pam_setenv(pamh, "HOME", pwd->pw_dir, 1); 658 (void)pam_setenv(pamh, "SHELL", pwd->pw_shell, 1); 659 (void)pam_setenv(pamh, "USER", pwd->pw_name, 1); 660 (void)pam_setenv(pamh, "PATH", _PATH_DEFPATH, 1); 661 environ = pam_getenvlist(pamh); 662 (void)pam_end(pamh, pam_err); 663 #else 664 #ifdef LOGIN_CAP 665 { 666 char *sh; 667 if ((sh = login_getcapstr(lc, "shell", NULL, NULL))) { 668 if(!(sh = strdup(sh))) { 669 syslog(LOG_ERR, "Cannot alloc mem"); 670 exit(EXIT_FAILURE); 671 } 672 pwd->pw_shell = sh; 673 } 674 } 675 #endif 676 { 677 static char *envinit[] = { NULL }; 678 environ = envinit; 679 } 680 setenv("PATH", _PATH_DEFPATH, 1); 681 setenv("HOME", pwd->pw_dir, 1); 682 setenv("SHELL", pwd->pw_shell, 1); 683 setenv("USER", pwd->pw_name, 1); 684 #endif 685 686 cp = strrchr(pwd->pw_shell, '/'); 687 if (cp) 688 cp++; 689 else 690 cp = pwd->pw_shell; 691 692 #ifdef LOGIN_CAP 693 if (setusercontext(lc, pwd, pwd->pw_uid, 694 LOGIN_SETALL & ~LOGIN_SETGROUP) < 0) { 695 syslog(LOG_ERR, "setusercontext(): %m"); 696 exit(EXIT_FAILURE); 697 } 698 login_close(lc); 699 #else 700 (void)setgid((gid_t)pwd->pw_gid); 701 (void)setuid((uid_t)pwd->pw_uid); 702 #endif 703 endpwent(); 704 if (log_success || pwd->pw_uid == 0) { 705 syslog(LOG_INFO|LOG_AUTH, "%s@%s as %s: cmd='%.80s'", 706 remuser, hostname, locuser, cmdbuf); 707 } 708 (void)execl(pwd->pw_shell, cp, "-c", cmdbuf, NULL); 709 rshd_errx(EXIT_FAILURE, "%s: %s", pwd->pw_shell, strerror(errno)); 710 badlogin: 711 syslog(LOG_INFO|LOG_AUTH, 712 "%s@%s as %s: permission denied (%s). cmd='%.80s'", 713 remuser, hostname, locuser, errormsg, cmdbuf); 714 rshd_errx(EXIT_FAILURE, errorstr, errorhost); 715 } 716 717 /* 718 * Report error to client. Note: can't be used until second socket has 719 * connected to client, or older clients will hang waiting for that 720 * connection first. 721 */ 722 723 #include <stdarg.h> 724 725 static void 726 rshd_errx(int error, const char *fmt, ...) 727 { 728 va_list ap; 729 int len, rv; 730 char *bp, buf[BUFSIZ]; 731 va_start(ap, fmt); 732 bp = buf; 733 if (sent_null == 0) { 734 *bp++ = 1; 735 len = 1; 736 } else 737 len = 0; 738 rv = vsnprintf(bp, sizeof(buf) - 2, fmt, ap); 739 bp[rv++] = '\n'; 740 (void)write(STDERR_FILENO, buf, len + rv); 741 va_end(ap); 742 exit(error); 743 } 744 745 static void 746 getstr(char *buf, int cnt, const char *err) 747 { 748 char c; 749 750 do { 751 if (read(STDIN_FILENO, &c, 1) != 1) 752 exit(EXIT_FAILURE); 753 *buf++ = c; 754 if (--cnt == 0) 755 rshd_errx(EXIT_FAILURE, "%s too long", err); 756 } while (c != 0); 757 } 758 759 /* 760 * Check whether host h is in our local domain, 761 * defined as sharing the last two components of the domain part, 762 * or the entire domain part if the local domain has only one component. 763 * If either name is unqualified (contains no '.'), 764 * assume that the host is local, as it will be 765 * interpreted as such. 766 */ 767 static int 768 local_domain(char *h) 769 { 770 char localhost[MAXHOSTNAMELEN + 1]; 771 char *p1, *p2; 772 773 localhost[0] = 0; 774 (void)gethostname(localhost, sizeof(localhost)); 775 localhost[sizeof(localhost) - 1] = '\0'; 776 p1 = topdomain(localhost); 777 p2 = topdomain(h); 778 if (p1 == NULL || p2 == NULL || !strcasecmp(p1, p2)) 779 return (1); 780 return (0); 781 } 782 783 static char * 784 topdomain(char *h) 785 { 786 char *p, *maybe = NULL; 787 int dots = 0; 788 789 for (p = h + strlen(h); p >= h; p--) { 790 if (*p == '.') { 791 if (++dots == 2) 792 return (p); 793 maybe = p; 794 } 795 } 796 return (maybe); 797 } 798 799 static void 800 usage(void) 801 { 802 803 syslog(LOG_ERR, "Usage: %s [-%s]", getprogname(), OPTIONS); 804 exit(EXIT_FAILURE); 805 } 806
Indexes created Sat Sep 20 22:09:52 GMT 2025