1 /* $OpenBSD: session.c,v 1.292 2017/09/12 06:32:07 djm Exp $ */ 2 /* 3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 4 * All rights reserved 5 * 6 * As far as I am concerned, the code I have written for this software 7 * can be used freely for any purpose. Any derived versions of this 8 * software must be clearly marked as such, and if the derived work is 9 * incompatible with the protocol description in the RFC file, it must be 10 * called by a name other than "ssh" or "Secure Shell". 11 * 12 * SSH2 support by Markus Friedl. 13 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 14 * 15 * Redistribution and use in source and binary forms, with or without 16 * modification, are permitted provided that the following conditions 17 * are met: 18 * 1. Redistributions of source code must retain the above copyright 19 * notice, this list of conditions and the following disclaimer. 20 * 2. Redistributions in binary form must reproduce the above copyright 21 * notice, this list of conditions and the following disclaimer in the 22 * documentation and/or other materials provided with the distribution. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 27 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 28 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 29 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 30 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 33 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 34 */ 35 36 #include "includes.h" 37 38 #include <sys/types.h> 39 #include <sys/param.h> 40 #ifdef HAVE_SYS_STAT_H 41 # include <sys/stat.h> 42 #endif 43 #include <sys/socket.h> 44 #include <sys/un.h> 45 #include <sys/wait.h> 46 47 #include <arpa/inet.h> 48 49 #include <ctype.h> 50 #include <errno.h> 51 #include <fcntl.h> 52 #include <grp.h> 53 #include <netdb.h> 54 #ifdef HAVE_PATHS_H 55 #include <paths.h> 56 #endif 57 #include <pwd.h> 58 #include <signal.h> 59 #include <stdarg.h> 60 #include <stdio.h> 61 #include <stdlib.h> 62 #include <string.h> 63 #include <unistd.h> 64 #include <limits.h> 65 66 #include "openbsd-compat/sys-queue.h" 67 #include "xmalloc.h" 68 #include "ssh.h" 69 #include "ssh2.h" 70 #include "sshpty.h" 71 #include "packet.h" 72 #include "buffer.h" 73 #include "match.h" 74 #include "uidswap.h" 75 #include "compat.h" 76 #include "channels.h" 77 #include "key.h" 78 #include "cipher.h" 79 #ifdef GSSAPI 80 #include "ssh-gss.h" 81 #endif 82 #include "hostfile.h" 83 #include "auth.h" 84 #include "auth-options.h" 85 #include "authfd.h" 86 #include "pathnames.h" 87 #include "log.h" 88 #include "misc.h" 89 #include "servconf.h" 90 #include "sshlogin.h" 91 #include "serverloop.h" 92 #include "canohost.h" 93 #include "session.h" 94 #include "kex.h" 95 #include "monitor_wrap.h" 96 #include "sftp.h" 97 #include "atomicio.h" 98 99 #if defined(KRB5) && defined(USE_AFS) 100 #include <kafs.h> 101 #endif 102 103 #ifdef WITH_SELINUX 104 #include <selinux/selinux.h> 105 #endif 106 107 #define IS_INTERNAL_SFTP(c) \ 108 (!strncmp(c, INTERNAL_SFTP_NAME, sizeof(INTERNAL_SFTP_NAME) - 1) && \ 109 (c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\0' || \ 110 c[sizeof(INTERNAL_SFTP_NAME) - 1] == ' ' || \ 111 c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\t')) 112 113 /* func */ 114 115 Session *session_new(void); 116 void session_set_fds(struct ssh *, Session *, int, int, int, int, int); 117 void session_pty_cleanup(Session *); 118 void session_proctitle(Session *); 119 int session_setup_x11fwd(struct ssh *, Session *); 120 int do_exec_pty(struct ssh *, Session *, const char *); 121 int do_exec_no_pty(struct ssh *, Session *, const char *); 122 int do_exec(struct ssh *, Session *, const char *); 123 void do_login(struct ssh *, Session *, const char *); 124 void do_child(struct ssh *, Session *, const char *); 125 #ifdef LOGIN_NEEDS_UTMPX 126 static void do_pre_login(Session *s); 127 #endif 128 void do_motd(void); 129 int check_quietlogin(Session *, const char *); 130 131 static void do_authenticated2(struct ssh *, Authctxt *); 132 133 static int session_pty_req(struct ssh *, Session *); 134 135 /* import */ 136 extern ServerOptions options; 137 extern char *__progname; 138 extern int debug_flag; 139 extern u_int utmp_len; 140 extern int startup_pipe; 141 extern void destroy_sensitive_data(void); 142 extern Buffer loginmsg; 143 144 /* original command from peer. */ 145 const char *original_command = NULL; 146 147 /* data */ 148 static int sessions_first_unused = -1; 149 static int sessions_nalloc = 0; 150 static Session *sessions = NULL; 151 152 #define SUBSYSTEM_NONE 0 153 #define SUBSYSTEM_EXT 1 154 #define SUBSYSTEM_INT_SFTP 2 155 #define SUBSYSTEM_INT_SFTP_ERROR 3 156 157 #ifdef HAVE_LOGIN_CAP 158 login_cap_t *lc; 159 #endif 160 161 static int is_child = 0; 162 static int in_chroot = 0; 163 164 /* File containing userauth info, if ExposeAuthInfo set */ 165 static char *auth_info_file = NULL; 166 167 /* Name and directory of socket for authentication agent forwarding. */ 168 static char *auth_sock_name = NULL; 169 static char *auth_sock_dir = NULL; 170 171 /* removes the agent forwarding socket */ 172 173 static void 174 auth_sock_cleanup_proc(struct passwd *pw) 175 { 176 if (auth_sock_name != NULL) { 177 temporarily_use_uid(pw); 178 unlink(auth_sock_name); 179 rmdir(auth_sock_dir); 180 auth_sock_name = NULL; 181 restore_uid(); 182 } 183 } 184 185 static int 186 auth_input_request_forwarding(struct ssh *ssh, struct passwd * pw) 187 { 188 Channel *nc; 189 int sock = -1; 190 191 if (auth_sock_name != NULL) { 192 error("authentication forwarding requested twice."); 193 return 0; 194 } 195 196 /* Temporarily drop privileged uid for mkdir/bind. */ 197 temporarily_use_uid(pw); 198 199 /* Allocate a buffer for the socket name, and format the name. */ 200 auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX"); 201 202 /* Create private directory for socket */ 203 if (mkdtemp(auth_sock_dir) == NULL) { 204 packet_send_debug("Agent forwarding disabled: " 205 "mkdtemp() failed: %.100s", strerror(errno)); 206 restore_uid(); 207 free(auth_sock_dir); 208 auth_sock_dir = NULL; 209 goto authsock_err; 210 } 211 212 xasprintf(&auth_sock_name, "%s/agent.%ld", 213 auth_sock_dir, (long) getpid()); 214 215 /* Start a Unix listener on auth_sock_name. */ 216 sock = unix_listener(auth_sock_name, SSH_LISTEN_BACKLOG, 0); 217 218 /* Restore the privileged uid. */ 219 restore_uid(); 220 221 /* Check for socket/bind/listen failure. */ 222 if (sock < 0) 223 goto authsock_err; 224 225 /* Allocate a channel for the authentication agent socket. */ 226 nc = channel_new(ssh, "auth socket", 227 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1, 228 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 229 0, "auth socket", 1); 230 nc->path = xstrdup(auth_sock_name); 231 return 1; 232 233 authsock_err: 234 free(auth_sock_name); 235 if (auth_sock_dir != NULL) { 236 rmdir(auth_sock_dir); 237 free(auth_sock_dir); 238 } 239 if (sock != -1) 240 close(sock); 241 auth_sock_name = NULL; 242 auth_sock_dir = NULL; 243 return 0; 244 } 245 246 static void 247 display_loginmsg(void) 248 { 249 if (buffer_len(&loginmsg) > 0) { 250 buffer_append(&loginmsg, "\0", 1); 251 printf("%s", (char *)buffer_ptr(&loginmsg)); 252 buffer_clear(&loginmsg); 253 } 254 } 255 256 static void 257 prepare_auth_info_file(struct passwd *pw, struct sshbuf *info) 258 { 259 int fd = -1, success = 0; 260 261 if (!options.expose_userauth_info || info == NULL) 262 return; 263 264 temporarily_use_uid(pw); 265 auth_info_file = xstrdup("/tmp/sshauth.XXXXXXXXXXXXXXX"); 266 if ((fd = mkstemp(auth_info_file)) == -1) { 267 error("%s: mkstemp: %s", __func__, strerror(errno)); 268 goto out; 269 } 270 if (atomicio(vwrite, fd, sshbuf_mutable_ptr(info), 271 sshbuf_len(info)) != sshbuf_len(info)) { 272 error("%s: write: %s", __func__, strerror(errno)); 273 goto out; 274 } 275 if (close(fd) != 0) { 276 error("%s: close: %s", __func__, strerror(errno)); 277 goto out; 278 } 279 success = 1; 280 out: 281 if (!success) { 282 if (fd != -1) 283 close(fd); 284 free(auth_info_file); 285 auth_info_file = NULL; 286 } 287 restore_uid(); 288 } 289 290 void 291 do_authenticated(struct ssh *ssh, Authctxt *authctxt) 292 { 293 setproctitle("%s", authctxt->pw->pw_name); 294 295 /* setup the channel layer */ 296 /* XXX - streamlocal? */ 297 if (no_port_forwarding_flag || options.disable_forwarding || 298 (options.allow_tcp_forwarding & FORWARD_LOCAL) == 0) 299 channel_disable_adm_local_opens(ssh); 300 else 301 channel_permit_all_opens(ssh); 302 303 auth_debug_send(); 304 305 prepare_auth_info_file(authctxt->pw, authctxt->session_info); 306 307 do_authenticated2(ssh, authctxt); 308 309 do_cleanup(ssh, authctxt); 310 } 311 312 /* Check untrusted xauth strings for metacharacters */ 313 static int 314 xauth_valid_string(const char *s) 315 { 316 size_t i; 317 318 for (i = 0; s[i] != '\0'; i++) { 319 if (!isalnum((u_char)s[i]) && 320 s[i] != '.' && s[i] != ':' && s[i] != '/' && 321 s[i] != '-' && s[i] != '_') 322 return 0; 323 } 324 return 1; 325 } 326 327 #define USE_PIPES 1 328 /* 329 * This is called to fork and execute a command when we have no tty. This 330 * will call do_child from the child, and server_loop from the parent after 331 * setting up file descriptors and such. 332 */ 333 int 334 do_exec_no_pty(struct ssh *ssh, Session *s, const char *command) 335 { 336 pid_t pid; 337 338 #ifdef USE_PIPES 339 int pin[2], pout[2], perr[2]; 340 341 if (s == NULL) 342 fatal("do_exec_no_pty: no session"); 343 344 /* Allocate pipes for communicating with the program. */ 345 if (pipe(pin) < 0) { 346 error("%s: pipe in: %.100s", __func__, strerror(errno)); 347 return -1; 348 } 349 if (pipe(pout) < 0) { 350 error("%s: pipe out: %.100s", __func__, strerror(errno)); 351 close(pin[0]); 352 close(pin[1]); 353 return -1; 354 } 355 if (pipe(perr) < 0) { 356 error("%s: pipe err: %.100s", __func__, 357 strerror(errno)); 358 close(pin[0]); 359 close(pin[1]); 360 close(pout[0]); 361 close(pout[1]); 362 return -1; 363 } 364 #else 365 int inout[2], err[2]; 366 367 if (s == NULL) 368 fatal("do_exec_no_pty: no session"); 369 370 /* Uses socket pairs to communicate with the program. */ 371 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) { 372 error("%s: socketpair #1: %.100s", __func__, strerror(errno)); 373 return -1; 374 } 375 if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) { 376 error("%s: socketpair #2: %.100s", __func__, 377 strerror(errno)); 378 close(inout[0]); 379 close(inout[1]); 380 return -1; 381 } 382 #endif 383 384 session_proctitle(s); 385 386 /* Fork the child. */ 387 switch ((pid = fork())) { 388 case -1: 389 error("%s: fork: %.100s", __func__, strerror(errno)); 390 #ifdef USE_PIPES 391 close(pin[0]); 392 close(pin[1]); 393 close(pout[0]); 394 close(pout[1]); 395 close(perr[0]); 396 close(perr[1]); 397 #else 398 close(inout[0]); 399 close(inout[1]); 400 close(err[0]); 401 close(err[1]); 402 #endif 403 return -1; 404 case 0: 405 is_child = 1; 406 407 /* 408 * Create a new session and process group since the 4.4BSD 409 * setlogin() affects the entire process group. 410 */ 411 if (setsid() < 0) 412 error("setsid failed: %.100s", strerror(errno)); 413 414 #ifdef USE_PIPES 415 /* 416 * Redirect stdin. We close the parent side of the socket 417 * pair, and make the child side the standard input. 418 */ 419 close(pin[1]); 420 if (dup2(pin[0], 0) < 0) 421 perror("dup2 stdin"); 422 close(pin[0]); 423 424 /* Redirect stdout. */ 425 close(pout[0]); 426 if (dup2(pout[1], 1) < 0) 427 perror("dup2 stdout"); 428 close(pout[1]); 429 430 /* Redirect stderr. */ 431 close(perr[0]); 432 if (dup2(perr[1], 2) < 0) 433 perror("dup2 stderr"); 434 close(perr[1]); 435 #else 436 /* 437 * Redirect stdin, stdout, and stderr. Stdin and stdout will 438 * use the same socket, as some programs (particularly rdist) 439 * seem to depend on it. 440 */ 441 close(inout[1]); 442 close(err[1]); 443 if (dup2(inout[0], 0) < 0) /* stdin */ 444 perror("dup2 stdin"); 445 if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */ 446 perror("dup2 stdout"); 447 close(inout[0]); 448 if (dup2(err[0], 2) < 0) /* stderr */ 449 perror("dup2 stderr"); 450 close(err[0]); 451 #endif 452 453 454 #ifdef _UNICOS 455 cray_init_job(s->pw); /* set up cray jid and tmpdir */ 456 #endif 457 458 /* Do processing for the child (exec command etc). */ 459 do_child(ssh, s, command); 460 /* NOTREACHED */ 461 default: 462 break; 463 } 464 465 #ifdef _UNICOS 466 signal(WJSIGNAL, cray_job_termination_handler); 467 #endif /* _UNICOS */ 468 #ifdef HAVE_CYGWIN 469 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE); 470 #endif 471 472 s->pid = pid; 473 /* Set interactive/non-interactive mode. */ 474 packet_set_interactive(s->display != NULL, 475 options.ip_qos_interactive, options.ip_qos_bulk); 476 477 /* 478 * Clear loginmsg, since it's the child's responsibility to display 479 * it to the user, otherwise multiple sessions may accumulate 480 * multiple copies of the login messages. 481 */ 482 buffer_clear(&loginmsg); 483 484 #ifdef USE_PIPES 485 /* We are the parent. Close the child sides of the pipes. */ 486 close(pin[0]); 487 close(pout[1]); 488 close(perr[1]); 489 490 session_set_fds(ssh, s, pin[1], pout[0], perr[0], 491 s->is_subsystem, 0); 492 #else 493 /* We are the parent. Close the child sides of the socket pairs. */ 494 close(inout[0]); 495 close(err[0]); 496 497 /* 498 * Enter the interactive session. Note: server_loop must be able to 499 * handle the case that fdin and fdout are the same. 500 */ 501 session_set_fds(s, inout[1], inout[1], err[1], 502 s->is_subsystem, 0); 503 #endif 504 return 0; 505 } 506 507 /* 508 * This is called to fork and execute a command when we have a tty. This 509 * will call do_child from the child, and server_loop from the parent after 510 * setting up file descriptors, controlling tty, updating wtmp, utmp, 511 * lastlog, and other such operations. 512 */ 513 int 514 do_exec_pty(struct ssh *ssh, Session *s, const char *command) 515 { 516 int fdout, ptyfd, ttyfd, ptymaster; 517 pid_t pid; 518 519 if (s == NULL) 520 fatal("do_exec_pty: no session"); 521 ptyfd = s->ptyfd; 522 ttyfd = s->ttyfd; 523 524 /* 525 * Create another descriptor of the pty master side for use as the 526 * standard input. We could use the original descriptor, but this 527 * simplifies code in server_loop. The descriptor is bidirectional. 528 * Do this before forking (and cleanup in the child) so as to 529 * detect and gracefully fail out-of-fd conditions. 530 */ 531 if ((fdout = dup(ptyfd)) < 0) { 532 error("%s: dup #1: %s", __func__, strerror(errno)); 533 close(ttyfd); 534 close(ptyfd); 535 return -1; 536 } 537 /* we keep a reference to the pty master */ 538 if ((ptymaster = dup(ptyfd)) < 0) { 539 error("%s: dup #2: %s", __func__, strerror(errno)); 540 close(ttyfd); 541 close(ptyfd); 542 close(fdout); 543 return -1; 544 } 545 546 /* Fork the child. */ 547 switch ((pid = fork())) { 548 case -1: 549 error("%s: fork: %.100s", __func__, strerror(errno)); 550 close(fdout); 551 close(ptymaster); 552 close(ttyfd); 553 close(ptyfd); 554 return -1; 555 case 0: 556 is_child = 1; 557 558 close(fdout); 559 close(ptymaster); 560 561 /* Close the master side of the pseudo tty. */ 562 close(ptyfd); 563 564 /* Make the pseudo tty our controlling tty. */ 565 pty_make_controlling_tty(&ttyfd, s->tty); 566 567 /* Redirect stdin/stdout/stderr from the pseudo tty. */ 568 if (dup2(ttyfd, 0) < 0) 569 error("dup2 stdin: %s", strerror(errno)); 570 if (dup2(ttyfd, 1) < 0) 571 error("dup2 stdout: %s", strerror(errno)); 572 if (dup2(ttyfd, 2) < 0) 573 error("dup2 stderr: %s", strerror(errno)); 574 575 /* Close the extra descriptor for the pseudo tty. */ 576 close(ttyfd); 577 578 /* record login, etc. similar to login(1) */ 579 #ifdef _UNICOS 580 cray_init_job(s->pw); /* set up cray jid and tmpdir */ 581 #endif /* _UNICOS */ 582 #ifndef HAVE_OSF_SIA 583 do_login(ssh, s, command); 584 #endif 585 /* 586 * Do common processing for the child, such as execing 587 * the command. 588 */ 589 do_child(ssh, s, command); 590 /* NOTREACHED */ 591 default: 592 break; 593 } 594 595 #ifdef _UNICOS 596 signal(WJSIGNAL, cray_job_termination_handler); 597 #endif /* _UNICOS */ 598 #ifdef HAVE_CYGWIN 599 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE); 600 #endif 601 602 s->pid = pid; 603 604 /* Parent. Close the slave side of the pseudo tty. */ 605 close(ttyfd); 606 607 /* Enter interactive session. */ 608 s->ptymaster = ptymaster; 609 packet_set_interactive(1, 610 options.ip_qos_interactive, options.ip_qos_bulk); 611 session_set_fds(ssh, s, ptyfd, fdout, -1, 1, 1); 612 return 0; 613 } 614 615 #ifdef LOGIN_NEEDS_UTMPX 616 static void 617 do_pre_login(Session *s) 618 { 619 struct ssh *ssh = active_state; /* XXX */ 620 socklen_t fromlen; 621 struct sockaddr_storage from; 622 pid_t pid = getpid(); 623 624 /* 625 * Get IP address of client. If the connection is not a socket, let 626 * the address be 0.0.0.0. 627 */ 628 memset(&from, 0, sizeof(from)); 629 fromlen = sizeof(from); 630 if (packet_connection_is_on_socket()) { 631 if (getpeername(packet_get_connection_in(), 632 (struct sockaddr *)&from, &fromlen) < 0) { 633 debug("getpeername: %.100s", strerror(errno)); 634 cleanup_exit(255); 635 } 636 } 637 638 record_utmp_only(pid, s->tty, s->pw->pw_name, 639 session_get_remote_name_or_ip(ssh, utmp_len, options.use_dns), 640 (struct sockaddr *)&from, fromlen); 641 } 642 #endif 643 644 /* 645 * This is called to fork and execute a command. If another command is 646 * to be forced, execute that instead. 647 */ 648 int 649 do_exec(struct ssh *ssh, Session *s, const char *command) 650 { 651 int ret; 652 const char *forced = NULL, *tty = NULL; 653 char session_type[1024]; 654 655 if (options.adm_forced_command) { 656 original_command = command; 657 command = options.adm_forced_command; 658 forced = "(config)"; 659 } else if (forced_command) { 660 original_command = command; 661 command = forced_command; 662 forced = "(key-option)"; 663 } 664 if (forced != NULL) { 665 if (IS_INTERNAL_SFTP(command)) { 666 s->is_subsystem = s->is_subsystem ? 667 SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR; 668 } else if (s->is_subsystem) 669 s->is_subsystem = SUBSYSTEM_EXT; 670 snprintf(session_type, sizeof(session_type), 671 "forced-command %s '%.900s'", forced, command); 672 } else if (s->is_subsystem) { 673 snprintf(session_type, sizeof(session_type), 674 "subsystem '%.900s'", s->subsys); 675 } else if (command == NULL) { 676 snprintf(session_type, sizeof(session_type), "shell"); 677 } else { 678 /* NB. we don't log unforced commands to preserve privacy */ 679 snprintf(session_type, sizeof(session_type), "command"); 680 } 681 682 if (s->ttyfd != -1) { 683 tty = s->tty; 684 if (strncmp(tty, "/dev/", 5) == 0) 685 tty += 5; 686 } 687 688 verbose("Starting session: %s%s%s for %s from %.200s port %d id %d", 689 session_type, 690 tty == NULL ? "" : " on ", 691 tty == NULL ? "" : tty, 692 s->pw->pw_name, 693 ssh_remote_ipaddr(ssh), 694 ssh_remote_port(ssh), 695 s->self); 696 697 #ifdef SSH_AUDIT_EVENTS 698 if (command != NULL) 699 PRIVSEP(audit_run_command(command)); 700 else if (s->ttyfd == -1) { 701 char *shell = s->pw->pw_shell; 702 703 if (shell[0] == '\0') /* empty shell means /bin/sh */ 704 shell =_PATH_BSHELL; 705 PRIVSEP(audit_run_command(shell)); 706 } 707 #endif 708 if (s->ttyfd != -1) 709 ret = do_exec_pty(ssh, s, command); 710 else 711 ret = do_exec_no_pty(ssh, s, command); 712 713 original_command = NULL; 714 715 /* 716 * Clear loginmsg: it's the child's responsibility to display 717 * it to the user, otherwise multiple sessions may accumulate 718 * multiple copies of the login messages. 719 */ 720 buffer_clear(&loginmsg); 721 722 return ret; 723 } 724 725 /* administrative, login(1)-like work */ 726 void 727 do_login(struct ssh *ssh, Session *s, const char *command) 728 { 729 socklen_t fromlen; 730 struct sockaddr_storage from; 731 struct passwd * pw = s->pw; 732 pid_t pid = getpid(); 733 734 /* 735 * Get IP address of client. If the connection is not a socket, let 736 * the address be 0.0.0.0. 737 */ 738 memset(&from, 0, sizeof(from)); 739 fromlen = sizeof(from); 740 if (packet_connection_is_on_socket()) { 741 if (getpeername(packet_get_connection_in(), 742 (struct sockaddr *)&from, &fromlen) < 0) { 743 debug("getpeername: %.100s", strerror(errno)); 744 cleanup_exit(255); 745 } 746 } 747 748 /* Record that there was a login on that tty from the remote host. */ 749 if (!use_privsep) 750 record_login(pid, s->tty, pw->pw_name, pw->pw_uid, 751 session_get_remote_name_or_ip(ssh, utmp_len, 752 options.use_dns), 753 (struct sockaddr *)&from, fromlen); 754 755 #ifdef USE_PAM 756 /* 757 * If password change is needed, do it now. 758 * This needs to occur before the ~/.hushlogin check. 759 */ 760 if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) { 761 display_loginmsg(); 762 do_pam_chauthtok(); 763 s->authctxt->force_pwchange = 0; 764 /* XXX - signal [net] parent to enable forwardings */ 765 } 766 #endif 767 768 if (check_quietlogin(s, command)) 769 return; 770 771 display_loginmsg(); 772 773 do_motd(); 774 } 775 776 /* 777 * Display the message of the day. 778 */ 779 void 780 do_motd(void) 781 { 782 FILE *f; 783 char buf[256]; 784 785 if (options.print_motd) { 786 #ifdef HAVE_LOGIN_CAP 787 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd", 788 "/etc/motd"), "r"); 789 #else 790 f = fopen("/etc/motd", "r"); 791 #endif 792 if (f) { 793 while (fgets(buf, sizeof(buf), f)) 794 fputs(buf, stdout); 795 fclose(f); 796 } 797 } 798 } 799 800 801 /* 802 * Check for quiet login, either .hushlogin or command given. 803 */ 804 int 805 check_quietlogin(Session *s, const char *command) 806 { 807 char buf[256]; 808 struct passwd *pw = s->pw; 809 struct stat st; 810 811 /* Return 1 if .hushlogin exists or a command given. */ 812 if (command != NULL) 813 return 1; 814 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir); 815 #ifdef HAVE_LOGIN_CAP 816 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0) 817 return 1; 818 #else 819 if (stat(buf, &st) >= 0) 820 return 1; 821 #endif 822 return 0; 823 } 824 825 /* 826 * Reads environment variables from the given file and adds/overrides them 827 * into the environment. If the file does not exist, this does nothing. 828 * Otherwise, it must consist of empty lines, comments (line starts with '#') 829 * and assignments of the form name=value. No other forms are allowed. 830 */ 831 static void 832 read_environment_file(char ***env, u_int *envsize, 833 const char *filename) 834 { 835 FILE *f; 836 char buf[4096]; 837 char *cp, *value; 838 u_int lineno = 0; 839 840 f = fopen(filename, "r"); 841 if (!f) 842 return; 843 844 while (fgets(buf, sizeof(buf), f)) { 845 if (++lineno > 1000) 846 fatal("Too many lines in environment file %s", filename); 847 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++) 848 ; 849 if (!*cp || *cp == '#' || *cp == '\n') 850 continue; 851 852 cp[strcspn(cp, "\n")] = '\0'; 853 854 value = strchr(cp, '='); 855 if (value == NULL) { 856 fprintf(stderr, "Bad line %u in %.100s\n", lineno, 857 filename); 858 continue; 859 } 860 /* 861 * Replace the equals sign by nul, and advance value to 862 * the value string. 863 */ 864 *value = '\0'; 865 value++; 866 child_set_env(env, envsize, cp, value); 867 } 868 fclose(f); 869 } 870 871 #ifdef HAVE_ETC_DEFAULT_LOGIN 872 /* 873 * Return named variable from specified environment, or NULL if not present. 874 */ 875 static char * 876 child_get_env(char **env, const char *name) 877 { 878 int i; 879 size_t len; 880 881 len = strlen(name); 882 for (i=0; env[i] != NULL; i++) 883 if (strncmp(name, env[i], len) == 0 && env[i][len] == '=') 884 return(env[i] + len + 1); 885 return NULL; 886 } 887 888 /* 889 * Read /etc/default/login. 890 * We pick up the PATH (or SUPATH for root) and UMASK. 891 */ 892 static void 893 read_etc_default_login(char ***env, u_int *envsize, uid_t uid) 894 { 895 char **tmpenv = NULL, *var; 896 u_int i, tmpenvsize = 0; 897 u_long mask; 898 899 /* 900 * We don't want to copy the whole file to the child's environment, 901 * so we use a temporary environment and copy the variables we're 902 * interested in. 903 */ 904 read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login"); 905 906 if (tmpenv == NULL) 907 return; 908 909 if (uid == 0) 910 var = child_get_env(tmpenv, "SUPATH"); 911 else 912 var = child_get_env(tmpenv, "PATH"); 913 if (var != NULL) 914 child_set_env(env, envsize, "PATH", var); 915 916 if ((var = child_get_env(tmpenv, "UMASK")) != NULL) 917 if (sscanf(var, "%5lo", &mask) == 1) 918 umask((mode_t)mask); 919 920 for (i = 0; tmpenv[i] != NULL; i++) 921 free(tmpenv[i]); 922 free(tmpenv); 923 } 924 #endif /* HAVE_ETC_DEFAULT_LOGIN */ 925 926 static void 927 copy_environment_blacklist(char **source, char ***env, u_int *envsize, 928 const char *blacklist) 929 { 930 char *var_name, *var_val; 931 int i; 932 933 if (source == NULL) 934 return; 935 936 for(i = 0; source[i] != NULL; i++) { 937 var_name = xstrdup(source[i]); 938 if ((var_val = strstr(var_name, "=")) == NULL) { 939 free(var_name); 940 continue; 941 } 942 *var_val++ = '\0'; 943 944 if (blacklist == NULL || 945 match_pattern_list(var_name, blacklist, 0) != 1) { 946 debug3("Copy environment: %s=%s", var_name, var_val); 947 child_set_env(env, envsize, var_name, var_val); 948 } 949 950 free(var_name); 951 } 952 } 953 954 void 955 copy_environment(char **source, char ***env, u_int *envsize) 956 { 957 copy_environment_blacklist(source, env, envsize, NULL); 958 } 959 960 static char ** 961 do_setup_env(struct ssh *ssh, Session *s, const char *shell) 962 { 963 char buf[256]; 964 u_int i, envsize; 965 char **env, *laddr; 966 struct passwd *pw = s->pw; 967 #if !defined (HAVE_LOGIN_CAP) && !defined (HAVE_CYGWIN) 968 char *path = NULL; 969 #endif 970 971 /* Initialize the environment. */ 972 envsize = 100; 973 env = xcalloc(envsize, sizeof(char *)); 974 env[0] = NULL; 975 976 #ifdef HAVE_CYGWIN 977 /* 978 * The Windows environment contains some setting which are 979 * important for a running system. They must not be dropped. 980 */ 981 { 982 char **p; 983 984 p = fetch_windows_environment(); 985 copy_environment(p, &env, &envsize); 986 free_windows_environment(p); 987 } 988 #endif 989 990 #ifdef GSSAPI 991 /* Allow any GSSAPI methods that we've used to alter 992 * the childs environment as they see fit 993 */ 994 ssh_gssapi_do_child(&env, &envsize); 995 #endif 996 997 /* Set basic environment. */ 998 for (i = 0; i < s->num_env; i++) 999 child_set_env(&env, &envsize, s->env[i].name, s->env[i].val); 1000 1001 child_set_env(&env, &envsize, "USER", pw->pw_name); 1002 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name); 1003 #ifdef _AIX 1004 child_set_env(&env, &envsize, "LOGIN", pw->pw_name); 1005 #endif 1006 child_set_env(&env, &envsize, "HOME", pw->pw_dir); 1007 #ifdef HAVE_LOGIN_CAP 1008 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0) 1009 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH); 1010 else 1011 child_set_env(&env, &envsize, "PATH", getenv("PATH")); 1012 #else /* HAVE_LOGIN_CAP */ 1013 # ifndef HAVE_CYGWIN 1014 /* 1015 * There's no standard path on Windows. The path contains 1016 * important components pointing to the system directories, 1017 * needed for loading shared libraries. So the path better 1018 * remains intact here. 1019 */ 1020 # ifdef HAVE_ETC_DEFAULT_LOGIN 1021 read_etc_default_login(&env, &envsize, pw->pw_uid); 1022 path = child_get_env(env, "PATH"); 1023 # endif /* HAVE_ETC_DEFAULT_LOGIN */ 1024 if (path == NULL || *path == '\0') { 1025 child_set_env(&env, &envsize, "PATH", 1026 s->pw->pw_uid == 0 ? SUPERUSER_PATH : _PATH_STDPATH); 1027 } 1028 # endif /* HAVE_CYGWIN */ 1029 #endif /* HAVE_LOGIN_CAP */ 1030 1031 snprintf(buf, sizeof buf, "%.200s/%.50s", _PATH_MAILDIR, pw->pw_name); 1032 child_set_env(&env, &envsize, "MAIL", buf); 1033 1034 /* Normal systems set SHELL by default. */ 1035 child_set_env(&env, &envsize, "SHELL", shell); 1036 1037 if (getenv("TZ")) 1038 child_set_env(&env, &envsize, "TZ", getenv("TZ")); 1039 1040 /* Set custom environment options from RSA authentication. */ 1041 while (custom_environment) { 1042 struct envstring *ce = custom_environment; 1043 char *str = ce->s; 1044 1045 for (i = 0; str[i] != '=' && str[i]; i++) 1046 ; 1047 if (str[i] == '=') { 1048 str[i] = 0; 1049 child_set_env(&env, &envsize, str, str + i + 1); 1050 } 1051 custom_environment = ce->next; 1052 free(ce->s); 1053 free(ce); 1054 } 1055 1056 /* SSH_CLIENT deprecated */ 1057 snprintf(buf, sizeof buf, "%.50s %d %d", 1058 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 1059 ssh_local_port(ssh)); 1060 child_set_env(&env, &envsize, "SSH_CLIENT", buf); 1061 1062 laddr = get_local_ipaddr(packet_get_connection_in()); 1063 snprintf(buf, sizeof buf, "%.50s %d %.50s %d", 1064 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 1065 laddr, ssh_local_port(ssh)); 1066 free(laddr); 1067 child_set_env(&env, &envsize, "SSH_CONNECTION", buf); 1068 1069 if (auth_info_file != NULL) 1070 child_set_env(&env, &envsize, "SSH_USER_AUTH", auth_info_file); 1071 if (s->ttyfd != -1) 1072 child_set_env(&env, &envsize, "SSH_TTY", s->tty); 1073 if (s->term) 1074 child_set_env(&env, &envsize, "TERM", s->term); 1075 if (s->display) 1076 child_set_env(&env, &envsize, "DISPLAY", s->display); 1077 if (original_command) 1078 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND", 1079 original_command); 1080 1081 #ifdef _UNICOS 1082 if (cray_tmpdir[0] != '\0') 1083 child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir); 1084 #endif /* _UNICOS */ 1085 1086 /* 1087 * Since we clear KRB5CCNAME at startup, if it's set now then it 1088 * must have been set by a native authentication method (eg AIX or 1089 * SIA), so copy it to the child. 1090 */ 1091 { 1092 char *cp; 1093 1094 if ((cp = getenv("KRB5CCNAME")) != NULL) 1095 child_set_env(&env, &envsize, "KRB5CCNAME", cp); 1096 } 1097 1098 #ifdef _AIX 1099 { 1100 char *cp; 1101 1102 if ((cp = getenv("AUTHSTATE")) != NULL) 1103 child_set_env(&env, &envsize, "AUTHSTATE", cp); 1104 read_environment_file(&env, &envsize, "/etc/environment"); 1105 } 1106 #endif 1107 #ifdef KRB5 1108 if (s->authctxt->krb5_ccname) 1109 child_set_env(&env, &envsize, "KRB5CCNAME", 1110 s->authctxt->krb5_ccname); 1111 #endif 1112 #ifdef USE_PAM 1113 /* 1114 * Pull in any environment variables that may have 1115 * been set by PAM. 1116 */ 1117 if (options.use_pam) { 1118 char **p; 1119 1120 /* 1121 * Don't allow SSH_AUTH_INFO variables posted to PAM to leak 1122 * back into the environment. 1123 */ 1124 p = fetch_pam_child_environment(); 1125 copy_environment_blacklist(p, &env, &envsize, "SSH_AUTH_INFO*"); 1126 free_pam_environment(p); 1127 1128 p = fetch_pam_environment(); 1129 copy_environment_blacklist(p, &env, &envsize, "SSH_AUTH_INFO*"); 1130 free_pam_environment(p); 1131 } 1132 #endif /* USE_PAM */ 1133 1134 if (auth_sock_name != NULL) 1135 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME, 1136 auth_sock_name); 1137 1138 /* read $HOME/.ssh/environment. */ 1139 if (options.permit_user_env) { 1140 snprintf(buf, sizeof buf, "%.200s/.ssh/environment", 1141 strcmp(pw->pw_dir, "/") ? pw->pw_dir : ""); 1142 read_environment_file(&env, &envsize, buf); 1143 } 1144 if (debug_flag) { 1145 /* dump the environment */ 1146 fprintf(stderr, "Environment:\n"); 1147 for (i = 0; env[i]; i++) 1148 fprintf(stderr, " %.200s\n", env[i]); 1149 } 1150 return env; 1151 } 1152 1153 /* 1154 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found 1155 * first in this order). 1156 */ 1157 static void 1158 do_rc_files(Session *s, const char *shell) 1159 { 1160 FILE *f = NULL; 1161 char cmd[1024]; 1162 int do_xauth; 1163 struct stat st; 1164 1165 do_xauth = 1166 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL; 1167 1168 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */ 1169 if (!s->is_subsystem && options.adm_forced_command == NULL && 1170 !no_user_rc && options.permit_user_rc && 1171 stat(_PATH_SSH_USER_RC, &st) >= 0) { 1172 snprintf(cmd, sizeof cmd, "%s -c '%s %s'", 1173 shell, _PATH_BSHELL, _PATH_SSH_USER_RC); 1174 if (debug_flag) 1175 fprintf(stderr, "Running %s\n", cmd); 1176 f = popen(cmd, "w"); 1177 if (f) { 1178 if (do_xauth) 1179 fprintf(f, "%s %s\n", s->auth_proto, 1180 s->auth_data); 1181 pclose(f); 1182 } else 1183 fprintf(stderr, "Could not run %s\n", 1184 _PATH_SSH_USER_RC); 1185 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) { 1186 if (debug_flag) 1187 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL, 1188 _PATH_SSH_SYSTEM_RC); 1189 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w"); 1190 if (f) { 1191 if (do_xauth) 1192 fprintf(f, "%s %s\n", s->auth_proto, 1193 s->auth_data); 1194 pclose(f); 1195 } else 1196 fprintf(stderr, "Could not run %s\n", 1197 _PATH_SSH_SYSTEM_RC); 1198 } else if (do_xauth && options.xauth_location != NULL) { 1199 /* Add authority data to .Xauthority if appropriate. */ 1200 if (debug_flag) { 1201 fprintf(stderr, 1202 "Running %.500s remove %.100s\n", 1203 options.xauth_location, s->auth_display); 1204 fprintf(stderr, 1205 "%.500s add %.100s %.100s %.100s\n", 1206 options.xauth_location, s->auth_display, 1207 s->auth_proto, s->auth_data); 1208 } 1209 snprintf(cmd, sizeof cmd, "%s -q -", 1210 options.xauth_location); 1211 f = popen(cmd, "w"); 1212 if (f) { 1213 fprintf(f, "remove %s\n", 1214 s->auth_display); 1215 fprintf(f, "add %s %s %s\n", 1216 s->auth_display, s->auth_proto, 1217 s->auth_data); 1218 pclose(f); 1219 } else { 1220 fprintf(stderr, "Could not run %s\n", 1221 cmd); 1222 } 1223 } 1224 } 1225 1226 static void 1227 do_nologin(struct passwd *pw) 1228 { 1229 FILE *f = NULL; 1230 char buf[1024], *nl, *def_nl = _PATH_NOLOGIN; 1231 struct stat sb; 1232 1233 #ifdef HAVE_LOGIN_CAP 1234 if (login_getcapbool(lc, "ignorenologin", 0) || pw->pw_uid == 0) 1235 return; 1236 nl = login_getcapstr(lc, "nologin", def_nl, def_nl); 1237 #else 1238 if (pw->pw_uid == 0) 1239 return; 1240 nl = def_nl; 1241 #endif 1242 if (stat(nl, &sb) == -1) { 1243 if (nl != def_nl) 1244 free(nl); 1245 return; 1246 } 1247 1248 /* /etc/nologin exists. Print its contents if we can and exit. */ 1249 logit("User %.100s not allowed because %s exists", pw->pw_name, nl); 1250 if ((f = fopen(nl, "r")) != NULL) { 1251 while (fgets(buf, sizeof(buf), f)) 1252 fputs(buf, stderr); 1253 fclose(f); 1254 } 1255 exit(254); 1256 } 1257 1258 /* 1259 * Chroot into a directory after checking it for safety: all path components 1260 * must be root-owned directories with strict permissions. 1261 */ 1262 static void 1263 safely_chroot(const char *path, uid_t uid) 1264 { 1265 const char *cp; 1266 char component[PATH_MAX]; 1267 struct stat st; 1268 1269 if (*path != '/') 1270 fatal("chroot path does not begin at root"); 1271 if (strlen(path) >= sizeof(component)) 1272 fatal("chroot path too long"); 1273 1274 /* 1275 * Descend the path, checking that each component is a 1276 * root-owned directory with strict permissions. 1277 */ 1278 for (cp = path; cp != NULL;) { 1279 if ((cp = strchr(cp, '/')) == NULL) 1280 strlcpy(component, path, sizeof(component)); 1281 else { 1282 cp++; 1283 memcpy(component, path, cp - path); 1284 component[cp - path] = '\0'; 1285 } 1286 1287 debug3("%s: checking '%s'", __func__, component); 1288 1289 if (stat(component, &st) != 0) 1290 fatal("%s: stat(\"%s\"): %s", __func__, 1291 component, strerror(errno)); 1292 if (st.st_uid != 0 || (st.st_mode & 022) != 0) 1293 fatal("bad ownership or modes for chroot " 1294 "directory %s\"%s\"", 1295 cp == NULL ? "" : "component ", component); 1296 if (!S_ISDIR(st.st_mode)) 1297 fatal("chroot path %s\"%s\" is not a directory", 1298 cp == NULL ? "" : "component ", component); 1299 1300 } 1301 1302 if (chdir(path) == -1) 1303 fatal("Unable to chdir to chroot path \"%s\": " 1304 "%s", path, strerror(errno)); 1305 if (chroot(path) == -1) 1306 fatal("chroot(\"%s\"): %s", path, strerror(errno)); 1307 if (chdir("/") == -1) 1308 fatal("%s: chdir(/) after chroot: %s", 1309 __func__, strerror(errno)); 1310 verbose("Changed root directory to \"%s\"", path); 1311 } 1312 1313 /* Set login name, uid, gid, and groups. */ 1314 void 1315 do_setusercontext(struct passwd *pw) 1316 { 1317 char *chroot_path, *tmp; 1318 1319 platform_setusercontext(pw); 1320 1321 if (platform_privileged_uidswap()) { 1322 #ifdef HAVE_LOGIN_CAP 1323 if (setusercontext(lc, pw, pw->pw_uid, 1324 (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) { 1325 perror("unable to set user context"); 1326 exit(1); 1327 } 1328 #else 1329 if (setlogin(pw->pw_name) < 0) 1330 error("setlogin failed: %s", strerror(errno)); 1331 if (setgid(pw->pw_gid) < 0) { 1332 perror("setgid"); 1333 exit(1); 1334 } 1335 /* Initialize the group list. */ 1336 if (initgroups(pw->pw_name, pw->pw_gid) < 0) { 1337 perror("initgroups"); 1338 exit(1); 1339 } 1340 endgrent(); 1341 #endif 1342 1343 platform_setusercontext_post_groups(pw); 1344 1345 if (!in_chroot && options.chroot_directory != NULL && 1346 strcasecmp(options.chroot_directory, "none") != 0) { 1347 tmp = tilde_expand_filename(options.chroot_directory, 1348 pw->pw_uid); 1349 chroot_path = percent_expand(tmp, "h", pw->pw_dir, 1350 "u", pw->pw_name, (char *)NULL); 1351 safely_chroot(chroot_path, pw->pw_uid); 1352 free(tmp); 1353 free(chroot_path); 1354 /* Make sure we don't attempt to chroot again */ 1355 free(options.chroot_directory); 1356 options.chroot_directory = NULL; 1357 in_chroot = 1; 1358 } 1359 1360 #ifdef HAVE_LOGIN_CAP 1361 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) { 1362 perror("unable to set user context (setuser)"); 1363 exit(1); 1364 } 1365 /* 1366 * FreeBSD's setusercontext() will not apply the user's 1367 * own umask setting unless running with the user's UID. 1368 */ 1369 (void) setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUMASK); 1370 #else 1371 # ifdef USE_LIBIAF 1372 /* 1373 * In a chroot environment, the set_id() will always fail; 1374 * typically because of the lack of necessary authentication 1375 * services and runtime such as ./usr/lib/libiaf.so, 1376 * ./usr/lib/libpam.so.1, and ./etc/passwd We skip it in the 1377 * internal sftp chroot case. We'll lose auditing and ACLs but 1378 * permanently_set_uid will take care of the rest. 1379 */ 1380 if (!in_chroot && set_id(pw->pw_name) != 0) 1381 fatal("set_id(%s) Failed", pw->pw_name); 1382 # endif /* USE_LIBIAF */ 1383 /* Permanently switch to the desired uid. */ 1384 permanently_set_uid(pw); 1385 #endif 1386 } else if (options.chroot_directory != NULL && 1387 strcasecmp(options.chroot_directory, "none") != 0) { 1388 fatal("server lacks privileges to chroot to ChrootDirectory"); 1389 } 1390 1391 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid) 1392 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid); 1393 } 1394 1395 static void 1396 do_pwchange(Session *s) 1397 { 1398 fflush(NULL); 1399 fprintf(stderr, "WARNING: Your password has expired.\n"); 1400 if (s->ttyfd != -1) { 1401 fprintf(stderr, 1402 "You must change your password now and login again!\n"); 1403 #ifdef WITH_SELINUX 1404 setexeccon(NULL); 1405 #endif 1406 #ifdef PASSWD_NEEDS_USERNAME 1407 execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name, 1408 (char *)NULL); 1409 #else 1410 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL); 1411 #endif 1412 perror("passwd"); 1413 } else { 1414 fprintf(stderr, 1415 "Password change required but no TTY available.\n"); 1416 } 1417 exit(1); 1418 } 1419 1420 static void 1421 child_close_fds(struct ssh *ssh) 1422 { 1423 extern int auth_sock; 1424 1425 if (auth_sock != -1) { 1426 close(auth_sock); 1427 auth_sock = -1; 1428 } 1429 1430 if (packet_get_connection_in() == packet_get_connection_out()) 1431 close(packet_get_connection_in()); 1432 else { 1433 close(packet_get_connection_in()); 1434 close(packet_get_connection_out()); 1435 } 1436 /* 1437 * Close all descriptors related to channels. They will still remain 1438 * open in the parent. 1439 */ 1440 /* XXX better use close-on-exec? -markus */ 1441 channel_close_all(ssh); 1442 1443 /* 1444 * Close any extra file descriptors. Note that there may still be 1445 * descriptors left by system functions. They will be closed later. 1446 */ 1447 endpwent(); 1448 1449 /* 1450 * Close any extra open file descriptors so that we don't have them 1451 * hanging around in clients. Note that we want to do this after 1452 * initgroups, because at least on Solaris 2.3 it leaves file 1453 * descriptors open. 1454 */ 1455 closefrom(STDERR_FILENO + 1); 1456 } 1457 1458 /* 1459 * Performs common processing for the child, such as setting up the 1460 * environment, closing extra file descriptors, setting the user and group 1461 * ids, and executing the command or shell. 1462 */ 1463 #define ARGV_MAX 10 1464 void 1465 do_child(struct ssh *ssh, Session *s, const char *command) 1466 { 1467 extern char **environ; 1468 char **env; 1469 char *argv[ARGV_MAX]; 1470 const char *shell, *shell0; 1471 struct passwd *pw = s->pw; 1472 int r = 0; 1473 1474 /* remove hostkey from the child's memory */ 1475 destroy_sensitive_data(); 1476 packet_clear_keys(); 1477 1478 /* Force a password change */ 1479 if (s->authctxt->force_pwchange) { 1480 do_setusercontext(pw); 1481 child_close_fds(ssh); 1482 do_pwchange(s); 1483 exit(1); 1484 } 1485 1486 #ifdef _UNICOS 1487 cray_setup(pw->pw_uid, pw->pw_name, command); 1488 #endif /* _UNICOS */ 1489 1490 /* 1491 * Login(1) does this as well, and it needs uid 0 for the "-h" 1492 * switch, so we let login(1) to this for us. 1493 */ 1494 #ifdef HAVE_OSF_SIA 1495 session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty); 1496 if (!check_quietlogin(s, command)) 1497 do_motd(); 1498 #else /* HAVE_OSF_SIA */ 1499 /* When PAM is enabled we rely on it to do the nologin check */ 1500 if (!options.use_pam) 1501 do_nologin(pw); 1502 do_setusercontext(pw); 1503 /* 1504 * PAM session modules in do_setusercontext may have 1505 * generated messages, so if this in an interactive 1506 * login then display them too. 1507 */ 1508 if (!check_quietlogin(s, command)) 1509 display_loginmsg(); 1510 #endif /* HAVE_OSF_SIA */ 1511 1512 #ifdef USE_PAM 1513 if (options.use_pam && !is_pam_session_open()) { 1514 debug3("PAM session not opened, exiting"); 1515 display_loginmsg(); 1516 exit(254); 1517 } 1518 #endif 1519 1520 /* 1521 * Get the shell from the password data. An empty shell field is 1522 * legal, and means /bin/sh. 1523 */ 1524 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell; 1525 1526 /* 1527 * Make sure $SHELL points to the shell from the password file, 1528 * even if shell is overridden from login.conf 1529 */ 1530 env = do_setup_env(ssh, s, shell); 1531 1532 #ifdef HAVE_LOGIN_CAP 1533 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell); 1534 #endif 1535 1536 /* 1537 * Close the connection descriptors; note that this is the child, and 1538 * the server will still have the socket open, and it is important 1539 * that we do not shutdown it. Note that the descriptors cannot be 1540 * closed before building the environment, as we call 1541 * ssh_remote_ipaddr there. 1542 */ 1543 child_close_fds(ssh); 1544 1545 /* 1546 * Must take new environment into use so that .ssh/rc, 1547 * /etc/ssh/sshrc and xauth are run in the proper environment. 1548 */ 1549 environ = env; 1550 1551 #if defined(KRB5) && defined(USE_AFS) 1552 /* 1553 * At this point, we check to see if AFS is active and if we have 1554 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see 1555 * if we can (and need to) extend the ticket into an AFS token. If 1556 * we don't do this, we run into potential problems if the user's 1557 * home directory is in AFS and it's not world-readable. 1558 */ 1559 1560 if (options.kerberos_get_afs_token && k_hasafs() && 1561 (s->authctxt->krb5_ctx != NULL)) { 1562 char cell[64]; 1563 1564 debug("Getting AFS token"); 1565 1566 k_setpag(); 1567 1568 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0) 1569 krb5_afslog(s->authctxt->krb5_ctx, 1570 s->authctxt->krb5_fwd_ccache, cell, NULL); 1571 1572 krb5_afslog_home(s->authctxt->krb5_ctx, 1573 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir); 1574 } 1575 #endif 1576 1577 /* Change current directory to the user's home directory. */ 1578 if (chdir(pw->pw_dir) < 0) { 1579 /* Suppress missing homedir warning for chroot case */ 1580 #ifdef HAVE_LOGIN_CAP 1581 r = login_getcapbool(lc, "requirehome", 0); 1582 #endif 1583 if (r || !in_chroot) { 1584 fprintf(stderr, "Could not chdir to home " 1585 "directory %s: %s\n", pw->pw_dir, 1586 strerror(errno)); 1587 } 1588 if (r) 1589 exit(1); 1590 } 1591 1592 closefrom(STDERR_FILENO + 1); 1593 1594 do_rc_files(s, shell); 1595 1596 /* restore SIGPIPE for child */ 1597 signal(SIGPIPE, SIG_DFL); 1598 1599 if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) { 1600 printf("This service allows sftp connections only.\n"); 1601 fflush(NULL); 1602 exit(1); 1603 } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) { 1604 extern int optind, optreset; 1605 int i; 1606 char *p, *args; 1607 1608 setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME); 1609 args = xstrdup(command ? command : "sftp-server"); 1610 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " "))) 1611 if (i < ARGV_MAX - 1) 1612 argv[i++] = p; 1613 argv[i] = NULL; 1614 optind = optreset = 1; 1615 __progname = argv[0]; 1616 #ifdef WITH_SELINUX 1617 ssh_selinux_change_context("sftpd_t"); 1618 #endif 1619 exit(sftp_server_main(i, argv, s->pw)); 1620 } 1621 1622 fflush(NULL); 1623 1624 /* Get the last component of the shell name. */ 1625 if ((shell0 = strrchr(shell, '/')) != NULL) 1626 shell0++; 1627 else 1628 shell0 = shell; 1629 1630 /* 1631 * If we have no command, execute the shell. In this case, the shell 1632 * name to be passed in argv[0] is preceded by '-' to indicate that 1633 * this is a login shell. 1634 */ 1635 if (!command) { 1636 char argv0[256]; 1637 1638 /* Start the shell. Set initial character to '-'. */ 1639 argv0[0] = '-'; 1640 1641 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1) 1642 >= sizeof(argv0) - 1) { 1643 errno = EINVAL; 1644 perror(shell); 1645 exit(1); 1646 } 1647 1648 /* Execute the shell. */ 1649 argv[0] = argv0; 1650 argv[1] = NULL; 1651 execve(shell, argv, env); 1652 1653 /* Executing the shell failed. */ 1654 perror(shell); 1655 exit(1); 1656 } 1657 /* 1658 * Execute the command using the user's shell. This uses the -c 1659 * option to execute the command. 1660 */ 1661 argv[0] = (char *) shell0; 1662 argv[1] = "-c"; 1663 argv[2] = (char *) command; 1664 argv[3] = NULL; 1665 execve(shell, argv, env); 1666 perror(shell); 1667 exit(1); 1668 } 1669 1670 void 1671 session_unused(int id) 1672 { 1673 debug3("%s: session id %d unused", __func__, id); 1674 if (id >= options.max_sessions || 1675 id >= sessions_nalloc) { 1676 fatal("%s: insane session id %d (max %d nalloc %d)", 1677 __func__, id, options.max_sessions, sessions_nalloc); 1678 } 1679 memset(&sessions[id], 0, sizeof(*sessions)); 1680 sessions[id].self = id; 1681 sessions[id].used = 0; 1682 sessions[id].chanid = -1; 1683 sessions[id].ptyfd = -1; 1684 sessions[id].ttyfd = -1; 1685 sessions[id].ptymaster = -1; 1686 sessions[id].x11_chanids = NULL; 1687 sessions[id].next_unused = sessions_first_unused; 1688 sessions_first_unused = id; 1689 } 1690 1691 Session * 1692 session_new(void) 1693 { 1694 Session *s, *tmp; 1695 1696 if (sessions_first_unused == -1) { 1697 if (sessions_nalloc >= options.max_sessions) 1698 return NULL; 1699 debug2("%s: allocate (allocated %d max %d)", 1700 __func__, sessions_nalloc, options.max_sessions); 1701 tmp = xrecallocarray(sessions, sessions_nalloc, 1702 sessions_nalloc + 1, sizeof(*sessions)); 1703 if (tmp == NULL) { 1704 error("%s: cannot allocate %d sessions", 1705 __func__, sessions_nalloc + 1); 1706 return NULL; 1707 } 1708 sessions = tmp; 1709 session_unused(sessions_nalloc++); 1710 } 1711 1712 if (sessions_first_unused >= sessions_nalloc || 1713 sessions_first_unused < 0) { 1714 fatal("%s: insane first_unused %d max %d nalloc %d", 1715 __func__, sessions_first_unused, options.max_sessions, 1716 sessions_nalloc); 1717 } 1718 1719 s = &sessions[sessions_first_unused]; 1720 if (s->used) { 1721 fatal("%s: session %d already used", 1722 __func__, sessions_first_unused); 1723 } 1724 sessions_first_unused = s->next_unused; 1725 s->used = 1; 1726 s->next_unused = -1; 1727 debug("session_new: session %d", s->self); 1728 1729 return s; 1730 } 1731 1732 static void 1733 session_dump(void) 1734 { 1735 int i; 1736 for (i = 0; i < sessions_nalloc; i++) { 1737 Session *s = &sessions[i]; 1738 1739 debug("dump: used %d next_unused %d session %d %p " 1740 "channel %d pid %ld", 1741 s->used, 1742 s->next_unused, 1743 s->self, 1744 s, 1745 s->chanid, 1746 (long)s->pid); 1747 } 1748 } 1749 1750 int 1751 session_open(Authctxt *authctxt, int chanid) 1752 { 1753 Session *s = session_new(); 1754 debug("session_open: channel %d", chanid); 1755 if (s == NULL) { 1756 error("no more sessions"); 1757 return 0; 1758 } 1759 s->authctxt = authctxt; 1760 s->pw = authctxt->pw; 1761 if (s->pw == NULL || !authctxt->valid) 1762 fatal("no user for session %d", s->self); 1763 debug("session_open: session %d: link with channel %d", s->self, chanid); 1764 s->chanid = chanid; 1765 return 1; 1766 } 1767 1768 Session * 1769 session_by_tty(char *tty) 1770 { 1771 int i; 1772 for (i = 0; i < sessions_nalloc; i++) { 1773 Session *s = &sessions[i]; 1774 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) { 1775 debug("session_by_tty: session %d tty %s", i, tty); 1776 return s; 1777 } 1778 } 1779 debug("session_by_tty: unknown tty %.100s", tty); 1780 session_dump(); 1781 return NULL; 1782 } 1783 1784 static Session * 1785 session_by_channel(int id) 1786 { 1787 int i; 1788 for (i = 0; i < sessions_nalloc; i++) { 1789 Session *s = &sessions[i]; 1790 if (s->used && s->chanid == id) { 1791 debug("session_by_channel: session %d channel %d", 1792 i, id); 1793 return s; 1794 } 1795 } 1796 debug("session_by_channel: unknown channel %d", id); 1797 session_dump(); 1798 return NULL; 1799 } 1800 1801 static Session * 1802 session_by_x11_channel(int id) 1803 { 1804 int i, j; 1805 1806 for (i = 0; i < sessions_nalloc; i++) { 1807 Session *s = &sessions[i]; 1808 1809 if (s->x11_chanids == NULL || !s->used) 1810 continue; 1811 for (j = 0; s->x11_chanids[j] != -1; j++) { 1812 if (s->x11_chanids[j] == id) { 1813 debug("session_by_x11_channel: session %d " 1814 "channel %d", s->self, id); 1815 return s; 1816 } 1817 } 1818 } 1819 debug("session_by_x11_channel: unknown channel %d", id); 1820 session_dump(); 1821 return NULL; 1822 } 1823 1824 static Session * 1825 session_by_pid(pid_t pid) 1826 { 1827 int i; 1828 debug("session_by_pid: pid %ld", (long)pid); 1829 for (i = 0; i < sessions_nalloc; i++) { 1830 Session *s = &sessions[i]; 1831 if (s->used && s->pid == pid) 1832 return s; 1833 } 1834 error("session_by_pid: unknown pid %ld", (long)pid); 1835 session_dump(); 1836 return NULL; 1837 } 1838 1839 static int 1840 session_window_change_req(struct ssh *ssh, Session *s) 1841 { 1842 s->col = packet_get_int(); 1843 s->row = packet_get_int(); 1844 s->xpixel = packet_get_int(); 1845 s->ypixel = packet_get_int(); 1846 packet_check_eom(); 1847 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel); 1848 return 1; 1849 } 1850 1851 static int 1852 session_pty_req(struct ssh *ssh, Session *s) 1853 { 1854 u_int len; 1855 int n_bytes; 1856 1857 if (no_pty_flag || !options.permit_tty) { 1858 debug("Allocating a pty not permitted for this authentication."); 1859 return 0; 1860 } 1861 if (s->ttyfd != -1) { 1862 packet_disconnect("Protocol error: you already have a pty."); 1863 return 0; 1864 } 1865 1866 s->term = packet_get_string(&len); 1867 s->col = packet_get_int(); 1868 s->row = packet_get_int(); 1869 s->xpixel = packet_get_int(); 1870 s->ypixel = packet_get_int(); 1871 1872 if (strcmp(s->term, "") == 0) { 1873 free(s->term); 1874 s->term = NULL; 1875 } 1876 1877 /* Allocate a pty and open it. */ 1878 debug("Allocating pty."); 1879 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, 1880 sizeof(s->tty)))) { 1881 free(s->term); 1882 s->term = NULL; 1883 s->ptyfd = -1; 1884 s->ttyfd = -1; 1885 error("session_pty_req: session %d alloc failed", s->self); 1886 return 0; 1887 } 1888 debug("session_pty_req: session %d alloc %s", s->self, s->tty); 1889 1890 n_bytes = packet_remaining(); 1891 tty_parse_modes(s->ttyfd, &n_bytes); 1892 1893 if (!use_privsep) 1894 pty_setowner(s->pw, s->tty); 1895 1896 /* Set window size from the packet. */ 1897 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel); 1898 1899 packet_check_eom(); 1900 session_proctitle(s); 1901 return 1; 1902 } 1903 1904 static int 1905 session_subsystem_req(struct ssh *ssh, Session *s) 1906 { 1907 struct stat st; 1908 u_int len; 1909 int success = 0; 1910 char *prog, *cmd; 1911 u_int i; 1912 1913 s->subsys = packet_get_string(&len); 1914 packet_check_eom(); 1915 debug2("subsystem request for %.100s by user %s", s->subsys, 1916 s->pw->pw_name); 1917 1918 for (i = 0; i < options.num_subsystems; i++) { 1919 if (strcmp(s->subsys, options.subsystem_name[i]) == 0) { 1920 prog = options.subsystem_command[i]; 1921 cmd = options.subsystem_args[i]; 1922 if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) { 1923 s->is_subsystem = SUBSYSTEM_INT_SFTP; 1924 debug("subsystem: %s", prog); 1925 } else { 1926 if (stat(prog, &st) < 0) 1927 debug("subsystem: cannot stat %s: %s", 1928 prog, strerror(errno)); 1929 s->is_subsystem = SUBSYSTEM_EXT; 1930 debug("subsystem: exec() %s", cmd); 1931 } 1932 success = do_exec(ssh, s, cmd) == 0; 1933 break; 1934 } 1935 } 1936 1937 if (!success) 1938 logit("subsystem request for %.100s by user %s failed, " 1939 "subsystem not found", s->subsys, s->pw->pw_name); 1940 1941 return success; 1942 } 1943 1944 static int 1945 session_x11_req(struct ssh *ssh, Session *s) 1946 { 1947 int success; 1948 1949 if (s->auth_proto != NULL || s->auth_data != NULL) { 1950 error("session_x11_req: session %d: " 1951 "x11 forwarding already active", s->self); 1952 return 0; 1953 } 1954 s->single_connection = packet_get_char(); 1955 s->auth_proto = packet_get_string(NULL); 1956 s->auth_data = packet_get_string(NULL); 1957 s->screen = packet_get_int(); 1958 packet_check_eom(); 1959 1960 if (xauth_valid_string(s->auth_proto) && 1961 xauth_valid_string(s->auth_data)) 1962 success = session_setup_x11fwd(ssh, s); 1963 else { 1964 success = 0; 1965 error("Invalid X11 forwarding data"); 1966 } 1967 if (!success) { 1968 free(s->auth_proto); 1969 free(s->auth_data); 1970 s->auth_proto = NULL; 1971 s->auth_data = NULL; 1972 } 1973 return success; 1974 } 1975 1976 static int 1977 session_shell_req(struct ssh *ssh, Session *s) 1978 { 1979 packet_check_eom(); 1980 return do_exec(ssh, s, NULL) == 0; 1981 } 1982 1983 static int 1984 session_exec_req(struct ssh *ssh, Session *s) 1985 { 1986 u_int len, success; 1987 1988 char *command = packet_get_string(&len); 1989 packet_check_eom(); 1990 success = do_exec(ssh, s, command) == 0; 1991 free(command); 1992 return success; 1993 } 1994 1995 static int 1996 session_break_req(struct ssh *ssh, Session *s) 1997 { 1998 1999 packet_get_int(); /* ignored */ 2000 packet_check_eom(); 2001 2002 if (s->ptymaster == -1 || tcsendbreak(s->ptymaster, 0) < 0) 2003 return 0; 2004 return 1; 2005 } 2006 2007 static int 2008 session_env_req(struct ssh *ssh, Session *s) 2009 { 2010 char *name, *val; 2011 u_int name_len, val_len, i; 2012 2013 name = packet_get_cstring(&name_len); 2014 val = packet_get_cstring(&val_len); 2015 packet_check_eom(); 2016 2017 /* Don't set too many environment variables */ 2018 if (s->num_env > 128) { 2019 debug2("Ignoring env request %s: too many env vars", name); 2020 goto fail; 2021 } 2022 2023 for (i = 0; i < options.num_accept_env; i++) { 2024 if (match_pattern(name, options.accept_env[i])) { 2025 debug2("Setting env %d: %s=%s", s->num_env, name, val); 2026 s->env = xrecallocarray(s->env, s->num_env, 2027 s->num_env + 1, sizeof(*s->env)); 2028 s->env[s->num_env].name = name; 2029 s->env[s->num_env].val = val; 2030 s->num_env++; 2031 return (1); 2032 } 2033 } 2034 debug2("Ignoring env request %s: disallowed name", name); 2035 2036 fail: 2037 free(name); 2038 free(val); 2039 return (0); 2040 } 2041 2042 static int 2043 session_auth_agent_req(struct ssh *ssh, Session *s) 2044 { 2045 static int called = 0; 2046 packet_check_eom(); 2047 if (no_agent_forwarding_flag || !options.allow_agent_forwarding) { 2048 debug("session_auth_agent_req: no_agent_forwarding_flag"); 2049 return 0; 2050 } 2051 if (called) { 2052 return 0; 2053 } else { 2054 called = 1; 2055 return auth_input_request_forwarding(ssh, s->pw); 2056 } 2057 } 2058 2059 int 2060 session_input_channel_req(struct ssh *ssh, Channel *c, const char *rtype) 2061 { 2062 int success = 0; 2063 Session *s; 2064 2065 if ((s = session_by_channel(c->self)) == NULL) { 2066 logit("%s: no session %d req %.100s", __func__, c->self, rtype); 2067 return 0; 2068 } 2069 debug("%s: session %d req %s", __func__, s->self, rtype); 2070 2071 /* 2072 * a session is in LARVAL state until a shell, a command 2073 * or a subsystem is executed 2074 */ 2075 if (c->type == SSH_CHANNEL_LARVAL) { 2076 if (strcmp(rtype, "shell") == 0) { 2077 success = session_shell_req(ssh, s); 2078 } else if (strcmp(rtype, "exec") == 0) { 2079 success = session_exec_req(ssh, s); 2080 } else if (strcmp(rtype, "pty-req") == 0) { 2081 success = session_pty_req(ssh, s); 2082 } else if (strcmp(rtype, "x11-req") == 0) { 2083 success = session_x11_req(ssh, s); 2084 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) { 2085 success = session_auth_agent_req(ssh, s); 2086 } else if (strcmp(rtype, "subsystem") == 0) { 2087 success = session_subsystem_req(ssh, s); 2088 } else if (strcmp(rtype, "env") == 0) { 2089 success = session_env_req(ssh, s); 2090 } 2091 } 2092 if (strcmp(rtype, "window-change") == 0) { 2093 success = session_window_change_req(ssh, s); 2094 } else if (strcmp(rtype, "break") == 0) { 2095 success = session_break_req(ssh, s); 2096 } 2097 2098 return success; 2099 } 2100 2101 void 2102 session_set_fds(struct ssh *ssh, Session *s, 2103 int fdin, int fdout, int fderr, int ignore_fderr, int is_tty) 2104 { 2105 /* 2106 * now that have a child and a pipe to the child, 2107 * we can activate our channel and register the fd's 2108 */ 2109 if (s->chanid == -1) 2110 fatal("no channel for session %d", s->self); 2111 channel_set_fds(ssh, s->chanid, 2112 fdout, fdin, fderr, 2113 ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ, 2114 1, is_tty, CHAN_SES_WINDOW_DEFAULT); 2115 } 2116 2117 /* 2118 * Function to perform pty cleanup. Also called if we get aborted abnormally 2119 * (e.g., due to a dropped connection). 2120 */ 2121 void 2122 session_pty_cleanup2(Session *s) 2123 { 2124 if (s == NULL) { 2125 error("session_pty_cleanup: no session"); 2126 return; 2127 } 2128 if (s->ttyfd == -1) 2129 return; 2130 2131 debug("session_pty_cleanup: session %d release %s", s->self, s->tty); 2132 2133 /* Record that the user has logged out. */ 2134 if (s->pid != 0) 2135 record_logout(s->pid, s->tty, s->pw->pw_name); 2136 2137 /* Release the pseudo-tty. */ 2138 if (getuid() == 0) 2139 pty_release(s->tty); 2140 2141 /* 2142 * Close the server side of the socket pairs. We must do this after 2143 * the pty cleanup, so that another process doesn't get this pty 2144 * while we're still cleaning up. 2145 */ 2146 if (s->ptymaster != -1 && close(s->ptymaster) < 0) 2147 error("close(s->ptymaster/%d): %s", 2148 s->ptymaster, strerror(errno)); 2149 2150 /* unlink pty from session */ 2151 s->ttyfd = -1; 2152 } 2153 2154 void 2155 session_pty_cleanup(Session *s) 2156 { 2157 PRIVSEP(session_pty_cleanup2(s)); 2158 } 2159 2160 static char * 2161 sig2name(int sig) 2162 { 2163 #define SSH_SIG(x) if (sig == SIG ## x) return #x 2164 SSH_SIG(ABRT); 2165 SSH_SIG(ALRM); 2166 SSH_SIG(FPE); 2167 SSH_SIG(HUP); 2168 SSH_SIG(ILL); 2169 SSH_SIG(INT); 2170 SSH_SIG(KILL); 2171 SSH_SIG(PIPE); 2172 SSH_SIG(QUIT); 2173 SSH_SIG(SEGV); 2174 SSH_SIG(TERM); 2175 SSH_SIG(USR1); 2176 SSH_SIG(USR2); 2177 #undef SSH_SIG 2178 return "SIG@openssh.com"; 2179 } 2180 2181 static void 2182 session_close_x11(struct ssh *ssh, int id) 2183 { 2184 Channel *c; 2185 2186 if ((c = channel_by_id(ssh, id)) == NULL) { 2187 debug("%s: x11 channel %d missing", __func__, id); 2188 } else { 2189 /* Detach X11 listener */ 2190 debug("%s: detach x11 channel %d", __func__, id); 2191 channel_cancel_cleanup(ssh, id); 2192 if (c->ostate != CHAN_OUTPUT_CLOSED) 2193 chan_mark_dead(ssh, c); 2194 } 2195 } 2196 2197 static void 2198 session_close_single_x11(struct ssh *ssh, int id, void *arg) 2199 { 2200 Session *s; 2201 u_int i; 2202 2203 debug3("%s: channel %d", __func__, id); 2204 channel_cancel_cleanup(ssh, id); 2205 if ((s = session_by_x11_channel(id)) == NULL) 2206 fatal("%s: no x11 channel %d", __func__, id); 2207 for (i = 0; s->x11_chanids[i] != -1; i++) { 2208 debug("%s: session %d: closing channel %d", 2209 __func__, s->self, s->x11_chanids[i]); 2210 /* 2211 * The channel "id" is already closing, but make sure we 2212 * close all of its siblings. 2213 */ 2214 if (s->x11_chanids[i] != id) 2215 session_close_x11(ssh, s->x11_chanids[i]); 2216 } 2217 free(s->x11_chanids); 2218 s->x11_chanids = NULL; 2219 free(s->display); 2220 s->display = NULL; 2221 free(s->auth_proto); 2222 s->auth_proto = NULL; 2223 free(s->auth_data); 2224 s->auth_data = NULL; 2225 free(s->auth_display); 2226 s->auth_display = NULL; 2227 } 2228 2229 static void 2230 session_exit_message(struct ssh *ssh, Session *s, int status) 2231 { 2232 Channel *c; 2233 2234 if ((c = channel_lookup(ssh, s->chanid)) == NULL) 2235 fatal("%s: session %d: no channel %d", 2236 __func__, s->self, s->chanid); 2237 debug("%s: session %d channel %d pid %ld", 2238 __func__, s->self, s->chanid, (long)s->pid); 2239 2240 if (WIFEXITED(status)) { 2241 channel_request_start(ssh, s->chanid, "exit-status", 0); 2242 packet_put_int(WEXITSTATUS(status)); 2243 packet_send(); 2244 } else if (WIFSIGNALED(status)) { 2245 channel_request_start(ssh, s->chanid, "exit-signal", 0); 2246 packet_put_cstring(sig2name(WTERMSIG(status))); 2247 #ifdef WCOREDUMP 2248 packet_put_char(WCOREDUMP(status)? 1 : 0); 2249 #else /* WCOREDUMP */ 2250 packet_put_char(0); 2251 #endif /* WCOREDUMP */ 2252 packet_put_cstring(""); 2253 packet_put_cstring(""); 2254 packet_send(); 2255 } else { 2256 /* Some weird exit cause. Just exit. */ 2257 packet_disconnect("wait returned status %04x.", status); 2258 } 2259 2260 /* disconnect channel */ 2261 debug("%s: release channel %d", __func__, s->chanid); 2262 2263 /* 2264 * Adjust cleanup callback attachment to send close messages when 2265 * the channel gets EOF. The session will be then be closed 2266 * by session_close_by_channel when the childs close their fds. 2267 */ 2268 channel_register_cleanup(ssh, c->self, session_close_by_channel, 1); 2269 2270 /* 2271 * emulate a write failure with 'chan_write_failed', nobody will be 2272 * interested in data we write. 2273 * Note that we must not call 'chan_read_failed', since there could 2274 * be some more data waiting in the pipe. 2275 */ 2276 if (c->ostate != CHAN_OUTPUT_CLOSED) 2277 chan_write_failed(ssh, c); 2278 } 2279 2280 void 2281 session_close(struct ssh *ssh, Session *s) 2282 { 2283 u_int i; 2284 2285 verbose("Close session: user %s from %.200s port %d id %d", 2286 s->pw->pw_name, 2287 ssh_remote_ipaddr(ssh), 2288 ssh_remote_port(ssh), 2289 s->self); 2290 2291 if (s->ttyfd != -1) 2292 session_pty_cleanup(s); 2293 free(s->term); 2294 free(s->display); 2295 free(s->x11_chanids); 2296 free(s->auth_display); 2297 free(s->auth_data); 2298 free(s->auth_proto); 2299 free(s->subsys); 2300 if (s->env != NULL) { 2301 for (i = 0; i < s->num_env; i++) { 2302 free(s->env[i].name); 2303 free(s->env[i].val); 2304 } 2305 free(s->env); 2306 } 2307 session_proctitle(s); 2308 session_unused(s->self); 2309 } 2310 2311 void 2312 session_close_by_pid(struct ssh *ssh, pid_t pid, int status) 2313 { 2314 Session *s = session_by_pid(pid); 2315 if (s == NULL) { 2316 debug("%s: no session for pid %ld", __func__, (long)pid); 2317 return; 2318 } 2319 if (s->chanid != -1) 2320 session_exit_message(ssh, s, status); 2321 if (s->ttyfd != -1) 2322 session_pty_cleanup(s); 2323 s->pid = 0; 2324 } 2325 2326 /* 2327 * this is called when a channel dies before 2328 * the session 'child' itself dies 2329 */ 2330 void 2331 session_close_by_channel(struct ssh *ssh, int id, void *arg) 2332 { 2333 Session *s = session_by_channel(id); 2334 u_int i; 2335 2336 if (s == NULL) { 2337 debug("%s: no session for id %d", __func__, id); 2338 return; 2339 } 2340 debug("%s: channel %d child %ld", __func__, id, (long)s->pid); 2341 if (s->pid != 0) { 2342 debug("%s: channel %d: has child", __func__, id); 2343 /* 2344 * delay detach of session, but release pty, since 2345 * the fd's to the child are already closed 2346 */ 2347 if (s->ttyfd != -1) 2348 session_pty_cleanup(s); 2349 return; 2350 } 2351 /* detach by removing callback */ 2352 channel_cancel_cleanup(ssh, s->chanid); 2353 2354 /* Close any X11 listeners associated with this session */ 2355 if (s->x11_chanids != NULL) { 2356 for (i = 0; s->x11_chanids[i] != -1; i++) { 2357 session_close_x11(ssh, s->x11_chanids[i]); 2358 s->x11_chanids[i] = -1; 2359 } 2360 } 2361 2362 s->chanid = -1; 2363 session_close(ssh, s); 2364 } 2365 2366 void 2367 session_destroy_all(struct ssh *ssh, void (*closefunc)(Session *)) 2368 { 2369 int i; 2370 for (i = 0; i < sessions_nalloc; i++) { 2371 Session *s = &sessions[i]; 2372 if (s->used) { 2373 if (closefunc != NULL) 2374 closefunc(s); 2375 else 2376 session_close(ssh, s); 2377 } 2378 } 2379 } 2380 2381 static char * 2382 session_tty_list(void) 2383 { 2384 static char buf[1024]; 2385 int i; 2386 char *cp; 2387 2388 buf[0] = '\0'; 2389 for (i = 0; i < sessions_nalloc; i++) { 2390 Session *s = &sessions[i]; 2391 if (s->used && s->ttyfd != -1) { 2392 2393 if (strncmp(s->tty, "/dev/", 5) != 0) { 2394 cp = strrchr(s->tty, '/'); 2395 cp = (cp == NULL) ? s->tty : cp + 1; 2396 } else 2397 cp = s->tty + 5; 2398 2399 if (buf[0] != '\0') 2400 strlcat(buf, ",", sizeof buf); 2401 strlcat(buf, cp, sizeof buf); 2402 } 2403 } 2404 if (buf[0] == '\0') 2405 strlcpy(buf, "notty", sizeof buf); 2406 return buf; 2407 } 2408 2409 void 2410 session_proctitle(Session *s) 2411 { 2412 if (s->pw == NULL) 2413 error("no user for session %d", s->self); 2414 else 2415 setproctitle("%s@%s", s->pw->pw_name, session_tty_list()); 2416 } 2417 2418 int 2419 session_setup_x11fwd(struct ssh *ssh, Session *s) 2420 { 2421 struct stat st; 2422 char display[512], auth_display[512]; 2423 char hostname[NI_MAXHOST]; 2424 u_int i; 2425 2426 if (no_x11_forwarding_flag) { 2427 packet_send_debug("X11 forwarding disabled in user configuration file."); 2428 return 0; 2429 } 2430 if (!options.x11_forwarding) { 2431 debug("X11 forwarding disabled in server configuration file."); 2432 return 0; 2433 } 2434 if (options.xauth_location == NULL || 2435 (stat(options.xauth_location, &st) == -1)) { 2436 packet_send_debug("No xauth program; cannot forward with spoofing."); 2437 return 0; 2438 } 2439 if (s->display != NULL) { 2440 debug("X11 display already set."); 2441 return 0; 2442 } 2443 if (x11_create_display_inet(ssh, options.x11_display_offset, 2444 options.x11_use_localhost, s->single_connection, 2445 &s->display_number, &s->x11_chanids) == -1) { 2446 debug("x11_create_display_inet failed."); 2447 return 0; 2448 } 2449 for (i = 0; s->x11_chanids[i] != -1; i++) { 2450 channel_register_cleanup(ssh, s->x11_chanids[i], 2451 session_close_single_x11, 0); 2452 } 2453 2454 /* Set up a suitable value for the DISPLAY variable. */ 2455 if (gethostname(hostname, sizeof(hostname)) < 0) 2456 fatal("gethostname: %.100s", strerror(errno)); 2457 /* 2458 * auth_display must be used as the displayname when the 2459 * authorization entry is added with xauth(1). This will be 2460 * different than the DISPLAY string for localhost displays. 2461 */ 2462 if (options.x11_use_localhost) { 2463 snprintf(display, sizeof display, "localhost:%u.%u", 2464 s->display_number, s->screen); 2465 snprintf(auth_display, sizeof auth_display, "unix:%u.%u", 2466 s->display_number, s->screen); 2467 s->display = xstrdup(display); 2468 s->auth_display = xstrdup(auth_display); 2469 } else { 2470 #ifdef IPADDR_IN_DISPLAY 2471 struct hostent *he; 2472 struct in_addr my_addr; 2473 2474 he = gethostbyname(hostname); 2475 if (he == NULL) { 2476 error("Can't get IP address for X11 DISPLAY."); 2477 packet_send_debug("Can't get IP address for X11 DISPLAY."); 2478 return 0; 2479 } 2480 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr)); 2481 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr), 2482 s->display_number, s->screen); 2483 #else 2484 snprintf(display, sizeof display, "%.400s:%u.%u", hostname, 2485 s->display_number, s->screen); 2486 #endif 2487 s->display = xstrdup(display); 2488 s->auth_display = xstrdup(display); 2489 } 2490 2491 return 1; 2492 } 2493 2494 static void 2495 do_authenticated2(struct ssh *ssh, Authctxt *authctxt) 2496 { 2497 server_loop2(ssh, authctxt); 2498 } 2499 2500 void 2501 do_cleanup(struct ssh *ssh, Authctxt *authctxt) 2502 { 2503 static int called = 0; 2504 2505 debug("do_cleanup"); 2506 2507 /* no cleanup if we're in the child for login shell */ 2508 if (is_child) 2509 return; 2510 2511 /* avoid double cleanup */ 2512 if (called) 2513 return; 2514 called = 1; 2515 2516 if (authctxt == NULL) 2517 return; 2518 2519 #ifdef USE_PAM 2520 if (options.use_pam) { 2521 sshpam_cleanup(); 2522 sshpam_thread_cleanup(); 2523 } 2524 #endif 2525 2526 if (!authctxt->authenticated) 2527 return; 2528 2529 #ifdef KRB5 2530 if (options.kerberos_ticket_cleanup && 2531 authctxt->krb5_ctx) 2532 krb5_cleanup_proc(authctxt); 2533 #endif 2534 2535 #ifdef GSSAPI 2536 if (options.gss_cleanup_creds) 2537 ssh_gssapi_cleanup_creds(); 2538 #endif 2539 2540 /* remove agent socket */ 2541 auth_sock_cleanup_proc(authctxt->pw); 2542 2543 /* remove userauth info */ 2544 if (auth_info_file != NULL) { 2545 temporarily_use_uid(authctxt->pw); 2546 unlink(auth_info_file); 2547 restore_uid(); 2548 free(auth_info_file); 2549 auth_info_file = NULL; 2550 } 2551 2552 /* 2553 * Cleanup ptys/utmp only if privsep is disabled, 2554 * or if running in monitor. 2555 */ 2556 if (!use_privsep || mm_is_monitor()) 2557 session_destroy_all(ssh, session_pty_cleanup2); 2558 } 2559 2560 /* Return a name for the remote host that fits inside utmp_size */ 2561 2562 const char * 2563 session_get_remote_name_or_ip(struct ssh *ssh, u_int utmp_size, int use_dns) 2564 { 2565 const char *remote = ""; 2566 2567 if (utmp_size > 0) 2568 remote = auth_get_canonical_hostname(ssh, use_dns); 2569 if (utmp_size == 0 || strlen(remote) > utmp_size) 2570 remote = ssh_remote_ipaddr(ssh); 2571 return remote; 2572 } 2573 2574