session.c revision 296953
1/* $OpenBSD: session.c,v 1.270 2014/01/31 16:39:19 tedu Exp $ */ 2/* $FreeBSD: releng/9.3/crypto/openssh/session.c 296953 2016-03-16 22:30:03Z glebius $ */ 3/* 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * 7 * As far as I am concerned, the code I have written for this software 8 * can be used freely for any purpose. Any derived versions of this 9 * software must be clearly marked as such, and if the derived work is 10 * incompatible with the protocol description in the RFC file, it must be 11 * called by a name other than "ssh" or "Secure Shell". 12 * 13 * SSH2 support by Markus Friedl. 14 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 15 * 16 * Redistribution and use in source and binary forms, with or without 17 * modification, are permitted provided that the following conditions 18 * are met: 19 * 1. Redistributions of source code must retain the above copyright 20 * notice, this list of conditions and the following disclaimer. 21 * 2. Redistributions in binary form must reproduce the above copyright 22 * notice, this list of conditions and the following disclaimer in the 23 * documentation and/or other materials provided with the distribution. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 26 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 27 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 28 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 29 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 30 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 31 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 32 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 34 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 35 */ 36 37#include "includes.h" 38__RCSID("$FreeBSD: releng/9.3/crypto/openssh/session.c 296953 2016-03-16 22:30:03Z glebius $"); 39 40#include <sys/types.h> 41#include <sys/param.h> 42#ifdef HAVE_SYS_STAT_H 43# include <sys/stat.h> 44#endif 45#include <sys/socket.h> 46#include <sys/un.h> 47#include <sys/wait.h> 48 49#include <arpa/inet.h> 50 51#include <ctype.h> 52#include <errno.h> 53#include <fcntl.h> 54#include <grp.h> 55#ifdef HAVE_PATHS_H 56#include <paths.h> 57#endif 58#include <pwd.h> 59#include <signal.h> 60#include <stdarg.h> 61#include <stdio.h> 62#include <stdlib.h> 63#include <string.h> 64#include <unistd.h> 65 66#include "openbsd-compat/sys-queue.h" 67#include "xmalloc.h" 68#include "ssh.h" 69#include "ssh1.h" 70#include "ssh2.h" 71#include "sshpty.h" 72#include "packet.h" 73#include "buffer.h" 74#include "match.h" 75#include "uidswap.h" 76#include "compat.h" 77#include "channels.h" 78#include "key.h" 79#include "cipher.h" 80#ifdef GSSAPI 81#include "ssh-gss.h" 82#endif 83#include "hostfile.h" 84#include "auth.h" 85#include "auth-options.h" 86#include "authfd.h" 87#include "pathnames.h" 88#include "log.h" 89#include "servconf.h" 90#include "sshlogin.h" 91#include "serverloop.h" 92#include "canohost.h" 93#include "misc.h" 94#include "session.h" 95#include "kex.h" 96#include "monitor_wrap.h" 97#include "sftp.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 115Session *session_new(void); 116void session_set_fds(Session *, int, int, int, int, int); 117void session_pty_cleanup(Session *); 118void session_proctitle(Session *); 119int session_setup_x11fwd(Session *); 120int do_exec_pty(Session *, const char *); 121int do_exec_no_pty(Session *, const char *); 122int do_exec(Session *, const char *); 123void do_login(Session *, const char *); 124#ifdef LOGIN_NEEDS_UTMPX 125static void do_pre_login(Session *s); 126#endif 127void do_child(Session *, const char *); 128void do_motd(void); 129int check_quietlogin(Session *, const char *); 130 131static void do_authenticated1(Authctxt *); 132static void do_authenticated2(Authctxt *); 133 134static int session_pty_req(Session *); 135 136/* import */ 137extern ServerOptions options; 138extern char *__progname; 139extern int log_stderr; 140extern int debug_flag; 141extern u_int utmp_len; 142extern int startup_pipe; 143extern void destroy_sensitive_data(void); 144extern Buffer loginmsg; 145 146/* original command from peer. */ 147const char *original_command = NULL; 148 149/* data */ 150static int sessions_first_unused = -1; 151static int sessions_nalloc = 0; 152static Session *sessions = NULL; 153 154#define SUBSYSTEM_NONE 0 155#define SUBSYSTEM_EXT 1 156#define SUBSYSTEM_INT_SFTP 2 157#define SUBSYSTEM_INT_SFTP_ERROR 3 158 159#ifdef HAVE_LOGIN_CAP 160login_cap_t *lc; 161#endif 162 163static int is_child = 0; 164 165/* Name and directory of socket for authentication agent forwarding. */ 166static char *auth_sock_name = NULL; 167static char *auth_sock_dir = NULL; 168 169/* removes the agent forwarding socket */ 170 171static void 172auth_sock_cleanup_proc(struct passwd *pw) 173{ 174 if (auth_sock_name != NULL) { 175 temporarily_use_uid(pw); 176 unlink(auth_sock_name); 177 rmdir(auth_sock_dir); 178 auth_sock_name = NULL; 179 restore_uid(); 180 } 181} 182 183static int 184auth_input_request_forwarding(struct passwd * pw) 185{ 186 Channel *nc; 187 int sock = -1; 188 struct sockaddr_un sunaddr; 189 190 if (auth_sock_name != NULL) { 191 error("authentication forwarding requested twice."); 192 return 0; 193 } 194 195 /* Temporarily drop privileged uid for mkdir/bind. */ 196 temporarily_use_uid(pw); 197 198 /* Allocate a buffer for the socket name, and format the name. */ 199 auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX"); 200 201 /* Create private directory for socket */ 202 if (mkdtemp(auth_sock_dir) == NULL) { 203 packet_send_debug("Agent forwarding disabled: " 204 "mkdtemp() failed: %.100s", strerror(errno)); 205 restore_uid(); 206 free(auth_sock_dir); 207 auth_sock_dir = NULL; 208 goto authsock_err; 209 } 210 211 xasprintf(&auth_sock_name, "%s/agent.%ld", 212 auth_sock_dir, (long) getpid()); 213 214 /* Create the socket. */ 215 sock = socket(AF_UNIX, SOCK_STREAM, 0); 216 if (sock < 0) { 217 error("socket: %.100s", strerror(errno)); 218 restore_uid(); 219 goto authsock_err; 220 } 221 222 /* Bind it to the name. */ 223 memset(&sunaddr, 0, sizeof(sunaddr)); 224 sunaddr.sun_family = AF_UNIX; 225 strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path)); 226 227 if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) { 228 error("bind: %.100s", strerror(errno)); 229 restore_uid(); 230 goto authsock_err; 231 } 232 233 /* Restore the privileged uid. */ 234 restore_uid(); 235 236 /* Start listening on the socket. */ 237 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { 238 error("listen: %.100s", strerror(errno)); 239 goto authsock_err; 240 } 241 242 /* 243 * Allocate a channel for the authentication agent socket. 244 * Ignore HPN on that one given no improvement expected. 245 */ 246 nc = channel_new("auth socket", 247 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1, 248 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 249 0, "auth socket", 1); 250 nc->path = xstrdup(auth_sock_name); 251 return 1; 252 253 authsock_err: 254 free(auth_sock_name); 255 if (auth_sock_dir != NULL) { 256 rmdir(auth_sock_dir); 257 free(auth_sock_dir); 258 } 259 if (sock != -1) 260 close(sock); 261 auth_sock_name = NULL; 262 auth_sock_dir = NULL; 263 return 0; 264} 265 266static void 267display_loginmsg(void) 268{ 269 if (buffer_len(&loginmsg) > 0) { 270 buffer_append(&loginmsg, "\0", 1); 271 printf("%s", (char *)buffer_ptr(&loginmsg)); 272 buffer_clear(&loginmsg); 273 } 274} 275 276void 277do_authenticated(Authctxt *authctxt) 278{ 279 setproctitle("%s", authctxt->pw->pw_name); 280 281 /* setup the channel layer */ 282 if (no_port_forwarding_flag || 283 (options.allow_tcp_forwarding & FORWARD_LOCAL) == 0) 284 channel_disable_adm_local_opens(); 285 else 286 channel_permit_all_opens(); 287 288 auth_debug_send(); 289 290 if (compat20) 291 do_authenticated2(authctxt); 292 else 293 do_authenticated1(authctxt); 294 295 do_cleanup(authctxt); 296} 297 298/* Check untrusted xauth strings for metacharacters */ 299static int 300xauth_valid_string(const char *s) 301{ 302 size_t i; 303 304 for (i = 0; s[i] != '\0'; i++) { 305 if (!isalnum((u_char)s[i]) && 306 s[i] != '.' && s[i] != ':' && s[i] != '/' && 307 s[i] != '-' && s[i] != '_') 308 return 0; 309 } 310 return 1; 311} 312 313/* 314 * Prepares for an interactive session. This is called after the user has 315 * been successfully authenticated. During this message exchange, pseudo 316 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings 317 * are requested, etc. 318 */ 319static void 320do_authenticated1(Authctxt *authctxt) 321{ 322 Session *s; 323 char *command; 324 int success, type, screen_flag; 325 int enable_compression_after_reply = 0; 326 u_int proto_len, data_len, dlen, compression_level = 0; 327 328 s = session_new(); 329 if (s == NULL) { 330 error("no more sessions"); 331 return; 332 } 333 s->authctxt = authctxt; 334 s->pw = authctxt->pw; 335 336 /* 337 * We stay in this loop until the client requests to execute a shell 338 * or a command. 339 */ 340 for (;;) { 341 success = 0; 342 343 /* Get a packet from the client. */ 344 type = packet_read(); 345 346 /* Process the packet. */ 347 switch (type) { 348 case SSH_CMSG_REQUEST_COMPRESSION: 349 compression_level = packet_get_int(); 350 packet_check_eom(); 351 if (compression_level < 1 || compression_level > 9) { 352 packet_send_debug("Received invalid compression level %d.", 353 compression_level); 354 break; 355 } 356 if (options.compression == COMP_NONE) { 357 debug2("compression disabled"); 358 break; 359 } 360 /* Enable compression after we have responded with SUCCESS. */ 361 enable_compression_after_reply = 1; 362 success = 1; 363 break; 364 365 case SSH_CMSG_REQUEST_PTY: 366 success = session_pty_req(s); 367 break; 368 369 case SSH_CMSG_X11_REQUEST_FORWARDING: 370 s->auth_proto = packet_get_string(&proto_len); 371 s->auth_data = packet_get_string(&data_len); 372 373 screen_flag = packet_get_protocol_flags() & 374 SSH_PROTOFLAG_SCREEN_NUMBER; 375 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag); 376 377 if (packet_remaining() == 4) { 378 if (!screen_flag) 379 debug2("Buggy client: " 380 "X11 screen flag missing"); 381 s->screen = packet_get_int(); 382 } else { 383 s->screen = 0; 384 } 385 packet_check_eom(); 386 if (xauth_valid_string(s->auth_proto) && 387 xauth_valid_string(s->auth_data)) 388 success = session_setup_x11fwd(s); 389 else { 390 success = 0; 391 error("Invalid X11 forwarding data"); 392 } 393 if (!success) { 394 free(s->auth_proto); 395 free(s->auth_data); 396 s->auth_proto = NULL; 397 s->auth_data = NULL; 398 } 399 break; 400 401 case SSH_CMSG_AGENT_REQUEST_FORWARDING: 402 if (!options.allow_agent_forwarding || 403 no_agent_forwarding_flag || compat13) { 404 debug("Authentication agent forwarding not permitted for this authentication."); 405 break; 406 } 407 debug("Received authentication agent forwarding request."); 408 success = auth_input_request_forwarding(s->pw); 409 break; 410 411 case SSH_CMSG_PORT_FORWARD_REQUEST: 412 if (no_port_forwarding_flag) { 413 debug("Port forwarding not permitted for this authentication."); 414 break; 415 } 416 if (!(options.allow_tcp_forwarding & FORWARD_REMOTE)) { 417 debug("Port forwarding not permitted."); 418 break; 419 } 420 debug("Received TCP/IP port forwarding request."); 421 if (channel_input_port_forward_request(s->pw->pw_uid == 0, 422 options.gateway_ports) < 0) { 423 debug("Port forwarding failed."); 424 break; 425 } 426 success = 1; 427 break; 428 429 case SSH_CMSG_MAX_PACKET_SIZE: 430 if (packet_set_maxsize(packet_get_int()) > 0) 431 success = 1; 432 break; 433 434 case SSH_CMSG_EXEC_SHELL: 435 case SSH_CMSG_EXEC_CMD: 436 if (type == SSH_CMSG_EXEC_CMD) { 437 command = packet_get_string(&dlen); 438 debug("Exec command '%.500s'", command); 439 if (do_exec(s, command) != 0) 440 packet_disconnect( 441 "command execution failed"); 442 free(command); 443 } else { 444 if (do_exec(s, NULL) != 0) 445 packet_disconnect( 446 "shell execution failed"); 447 } 448 packet_check_eom(); 449 session_close(s); 450 return; 451 452 default: 453 /* 454 * Any unknown messages in this phase are ignored, 455 * and a failure message is returned. 456 */ 457 logit("Unknown packet type received after authentication: %d", type); 458 } 459 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE); 460 packet_send(); 461 packet_write_wait(); 462 463 /* Enable compression now that we have replied if appropriate. */ 464 if (enable_compression_after_reply) { 465 enable_compression_after_reply = 0; 466 packet_start_compression(compression_level); 467 } 468 } 469} 470 471#define USE_PIPES 1 472/* 473 * This is called to fork and execute a command when we have no tty. This 474 * will call do_child from the child, and server_loop from the parent after 475 * setting up file descriptors and such. 476 */ 477int 478do_exec_no_pty(Session *s, const char *command) 479{ 480 pid_t pid; 481 482#ifdef USE_PIPES 483 int pin[2], pout[2], perr[2]; 484 485 if (s == NULL) 486 fatal("do_exec_no_pty: no session"); 487 488 /* Allocate pipes for communicating with the program. */ 489 if (pipe(pin) < 0) { 490 error("%s: pipe in: %.100s", __func__, strerror(errno)); 491 return -1; 492 } 493 if (pipe(pout) < 0) { 494 error("%s: pipe out: %.100s", __func__, strerror(errno)); 495 close(pin[0]); 496 close(pin[1]); 497 return -1; 498 } 499 if (pipe(perr) < 0) { 500 error("%s: pipe err: %.100s", __func__, 501 strerror(errno)); 502 close(pin[0]); 503 close(pin[1]); 504 close(pout[0]); 505 close(pout[1]); 506 return -1; 507 } 508#else 509 int inout[2], err[2]; 510 511 if (s == NULL) 512 fatal("do_exec_no_pty: no session"); 513 514 /* Uses socket pairs to communicate with the program. */ 515 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) { 516 error("%s: socketpair #1: %.100s", __func__, strerror(errno)); 517 return -1; 518 } 519 if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) { 520 error("%s: socketpair #2: %.100s", __func__, 521 strerror(errno)); 522 close(inout[0]); 523 close(inout[1]); 524 return -1; 525 } 526#endif 527 528 session_proctitle(s); 529 530 /* Fork the child. */ 531 switch ((pid = fork())) { 532 case -1: 533 error("%s: fork: %.100s", __func__, strerror(errno)); 534#ifdef USE_PIPES 535 close(pin[0]); 536 close(pin[1]); 537 close(pout[0]); 538 close(pout[1]); 539 close(perr[0]); 540 close(perr[1]); 541#else 542 close(inout[0]); 543 close(inout[1]); 544 close(err[0]); 545 close(err[1]); 546#endif 547 return -1; 548 case 0: 549 is_child = 1; 550 551 /* Child. Reinitialize the log since the pid has changed. */ 552 log_init(__progname, options.log_level, 553 options.log_facility, log_stderr); 554 555 /* 556 * Create a new session and process group since the 4.4BSD 557 * setlogin() affects the entire process group. 558 */ 559 if (setsid() < 0) 560 error("setsid failed: %.100s", strerror(errno)); 561 562#ifdef USE_PIPES 563 /* 564 * Redirect stdin. We close the parent side of the socket 565 * pair, and make the child side the standard input. 566 */ 567 close(pin[1]); 568 if (dup2(pin[0], 0) < 0) 569 perror("dup2 stdin"); 570 close(pin[0]); 571 572 /* Redirect stdout. */ 573 close(pout[0]); 574 if (dup2(pout[1], 1) < 0) 575 perror("dup2 stdout"); 576 close(pout[1]); 577 578 /* Redirect stderr. */ 579 close(perr[0]); 580 if (dup2(perr[1], 2) < 0) 581 perror("dup2 stderr"); 582 close(perr[1]); 583#else 584 /* 585 * Redirect stdin, stdout, and stderr. Stdin and stdout will 586 * use the same socket, as some programs (particularly rdist) 587 * seem to depend on it. 588 */ 589 close(inout[1]); 590 close(err[1]); 591 if (dup2(inout[0], 0) < 0) /* stdin */ 592 perror("dup2 stdin"); 593 if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */ 594 perror("dup2 stdout"); 595 close(inout[0]); 596 if (dup2(err[0], 2) < 0) /* stderr */ 597 perror("dup2 stderr"); 598 close(err[0]); 599#endif 600 601 602#ifdef _UNICOS 603 cray_init_job(s->pw); /* set up cray jid and tmpdir */ 604#endif 605 606 /* Do processing for the child (exec command etc). */ 607 do_child(s, command); 608 /* NOTREACHED */ 609 default: 610 break; 611 } 612 613#ifdef _UNICOS 614 signal(WJSIGNAL, cray_job_termination_handler); 615#endif /* _UNICOS */ 616#ifdef HAVE_CYGWIN 617 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE); 618#endif 619 620 s->pid = pid; 621 /* Set interactive/non-interactive mode. */ 622 packet_set_interactive(s->display != NULL, 623 options.ip_qos_interactive, options.ip_qos_bulk); 624 625 /* 626 * Clear loginmsg, since it's the child's responsibility to display 627 * it to the user, otherwise multiple sessions may accumulate 628 * multiple copies of the login messages. 629 */ 630 buffer_clear(&loginmsg); 631 632#ifdef USE_PIPES 633 /* We are the parent. Close the child sides of the pipes. */ 634 close(pin[0]); 635 close(pout[1]); 636 close(perr[1]); 637 638 if (compat20) { 639 session_set_fds(s, pin[1], pout[0], perr[0], 640 s->is_subsystem, 0); 641 } else { 642 /* Enter the interactive session. */ 643 server_loop(pid, pin[1], pout[0], perr[0]); 644 /* server_loop has closed pin[1], pout[0], and perr[0]. */ 645 } 646#else 647 /* We are the parent. Close the child sides of the socket pairs. */ 648 close(inout[0]); 649 close(err[0]); 650 651 /* 652 * Enter the interactive session. Note: server_loop must be able to 653 * handle the case that fdin and fdout are the same. 654 */ 655 if (compat20) { 656 session_set_fds(s, inout[1], inout[1], err[1], 657 s->is_subsystem, 0); 658 } else { 659 server_loop(pid, inout[1], inout[1], err[1]); 660 /* server_loop has closed inout[1] and err[1]. */ 661 } 662#endif 663 return 0; 664} 665 666/* 667 * This is called to fork and execute a command when we have a tty. This 668 * will call do_child from the child, and server_loop from the parent after 669 * setting up file descriptors, controlling tty, updating wtmp, utmp, 670 * lastlog, and other such operations. 671 */ 672int 673do_exec_pty(Session *s, const char *command) 674{ 675 int fdout, ptyfd, ttyfd, ptymaster; 676 pid_t pid; 677 678 if (s == NULL) 679 fatal("do_exec_pty: no session"); 680 ptyfd = s->ptyfd; 681 ttyfd = s->ttyfd; 682 683 /* 684 * Create another descriptor of the pty master side for use as the 685 * standard input. We could use the original descriptor, but this 686 * simplifies code in server_loop. The descriptor is bidirectional. 687 * Do this before forking (and cleanup in the child) so as to 688 * detect and gracefully fail out-of-fd conditions. 689 */ 690 if ((fdout = dup(ptyfd)) < 0) { 691 error("%s: dup #1: %s", __func__, strerror(errno)); 692 close(ttyfd); 693 close(ptyfd); 694 return -1; 695 } 696 /* we keep a reference to the pty master */ 697 if ((ptymaster = dup(ptyfd)) < 0) { 698 error("%s: dup #2: %s", __func__, strerror(errno)); 699 close(ttyfd); 700 close(ptyfd); 701 close(fdout); 702 return -1; 703 } 704 705 /* Fork the child. */ 706 switch ((pid = fork())) { 707 case -1: 708 error("%s: fork: %.100s", __func__, strerror(errno)); 709 close(fdout); 710 close(ptymaster); 711 close(ttyfd); 712 close(ptyfd); 713 return -1; 714 case 0: 715 is_child = 1; 716 717 close(fdout); 718 close(ptymaster); 719 720 /* Child. Reinitialize the log because the pid has changed. */ 721 log_init(__progname, options.log_level, 722 options.log_facility, log_stderr); 723 /* Close the master side of the pseudo tty. */ 724 close(ptyfd); 725 726 /* Make the pseudo tty our controlling tty. */ 727 pty_make_controlling_tty(&ttyfd, s->tty); 728 729 /* Redirect stdin/stdout/stderr from the pseudo tty. */ 730 if (dup2(ttyfd, 0) < 0) 731 error("dup2 stdin: %s", strerror(errno)); 732 if (dup2(ttyfd, 1) < 0) 733 error("dup2 stdout: %s", strerror(errno)); 734 if (dup2(ttyfd, 2) < 0) 735 error("dup2 stderr: %s", strerror(errno)); 736 737 /* Close the extra descriptor for the pseudo tty. */ 738 close(ttyfd); 739 740 /* record login, etc. similar to login(1) */ 741#ifndef HAVE_OSF_SIA 742 if (!(options.use_login && command == NULL)) { 743#ifdef _UNICOS 744 cray_init_job(s->pw); /* set up cray jid and tmpdir */ 745#endif /* _UNICOS */ 746 do_login(s, command); 747 } 748# ifdef LOGIN_NEEDS_UTMPX 749 else 750 do_pre_login(s); 751# endif 752#endif 753 /* 754 * Do common processing for the child, such as execing 755 * the command. 756 */ 757 do_child(s, command); 758 /* NOTREACHED */ 759 default: 760 break; 761 } 762 763#ifdef _UNICOS 764 signal(WJSIGNAL, cray_job_termination_handler); 765#endif /* _UNICOS */ 766#ifdef HAVE_CYGWIN 767 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE); 768#endif 769 770 s->pid = pid; 771 772 /* Parent. Close the slave side of the pseudo tty. */ 773 close(ttyfd); 774 775 /* Enter interactive session. */ 776 s->ptymaster = ptymaster; 777 packet_set_interactive(1, 778 options.ip_qos_interactive, options.ip_qos_bulk); 779 if (compat20) { 780 session_set_fds(s, ptyfd, fdout, -1, 1, 1); 781 } else { 782 server_loop(pid, ptyfd, fdout, -1); 783 /* server_loop _has_ closed ptyfd and fdout. */ 784 } 785 return 0; 786} 787 788#ifdef LOGIN_NEEDS_UTMPX 789static void 790do_pre_login(Session *s) 791{ 792 socklen_t fromlen; 793 struct sockaddr_storage from; 794 pid_t pid = getpid(); 795 796 /* 797 * Get IP address of client. If the connection is not a socket, let 798 * the address be 0.0.0.0. 799 */ 800 memset(&from, 0, sizeof(from)); 801 fromlen = sizeof(from); 802 if (packet_connection_is_on_socket()) { 803 if (getpeername(packet_get_connection_in(), 804 (struct sockaddr *)&from, &fromlen) < 0) { 805 debug("getpeername: %.100s", strerror(errno)); 806 cleanup_exit(255); 807 } 808 } 809 810 record_utmp_only(pid, s->tty, s->pw->pw_name, 811 get_remote_name_or_ip(utmp_len, options.use_dns), 812 (struct sockaddr *)&from, fromlen); 813} 814#endif 815 816/* 817 * This is called to fork and execute a command. If another command is 818 * to be forced, execute that instead. 819 */ 820int 821do_exec(Session *s, const char *command) 822{ 823 int ret; 824 const char *forced = NULL; 825 char session_type[1024], *tty = NULL; 826 827 if (options.adm_forced_command) { 828 original_command = command; 829 command = options.adm_forced_command; 830 forced = "(config)"; 831 } else if (forced_command) { 832 original_command = command; 833 command = forced_command; 834 forced = "(key-option)"; 835 } 836 if (forced != NULL) { 837 if (IS_INTERNAL_SFTP(command)) { 838 s->is_subsystem = s->is_subsystem ? 839 SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR; 840 } else if (s->is_subsystem) 841 s->is_subsystem = SUBSYSTEM_EXT; 842 snprintf(session_type, sizeof(session_type), 843 "forced-command %s '%.900s'", forced, command); 844 } else if (s->is_subsystem) { 845 snprintf(session_type, sizeof(session_type), 846 "subsystem '%.900s'", s->subsys); 847 } else if (command == NULL) { 848 snprintf(session_type, sizeof(session_type), "shell"); 849 } else { 850 /* NB. we don't log unforced commands to preserve privacy */ 851 snprintf(session_type, sizeof(session_type), "command"); 852 } 853 854 if (s->ttyfd != -1) { 855 tty = s->tty; 856 if (strncmp(tty, "/dev/", 5) == 0) 857 tty += 5; 858 } 859 860 verbose("Starting session: %s%s%s for %s from %.200s port %d", 861 session_type, 862 tty == NULL ? "" : " on ", 863 tty == NULL ? "" : tty, 864 s->pw->pw_name, 865 get_remote_ipaddr(), 866 get_remote_port()); 867 868#ifdef SSH_AUDIT_EVENTS 869 if (command != NULL) 870 PRIVSEP(audit_run_command(command)); 871 else if (s->ttyfd == -1) { 872 char *shell = s->pw->pw_shell; 873 874 if (shell[0] == '\0') /* empty shell means /bin/sh */ 875 shell =_PATH_BSHELL; 876 PRIVSEP(audit_run_command(shell)); 877 } 878#endif 879 if (s->ttyfd != -1) 880 ret = do_exec_pty(s, command); 881 else 882 ret = do_exec_no_pty(s, command); 883 884 original_command = NULL; 885 886 /* 887 * Clear loginmsg: it's the child's responsibility to display 888 * it to the user, otherwise multiple sessions may accumulate 889 * multiple copies of the login messages. 890 */ 891 buffer_clear(&loginmsg); 892 893 return ret; 894} 895 896/* administrative, login(1)-like work */ 897void 898do_login(Session *s, const char *command) 899{ 900 socklen_t fromlen; 901 struct sockaddr_storage from; 902 struct passwd * pw = s->pw; 903 pid_t pid = getpid(); 904 905 /* 906 * Get IP address of client. If the connection is not a socket, let 907 * the address be 0.0.0.0. 908 */ 909 memset(&from, 0, sizeof(from)); 910 fromlen = sizeof(from); 911 if (packet_connection_is_on_socket()) { 912 if (getpeername(packet_get_connection_in(), 913 (struct sockaddr *)&from, &fromlen) < 0) { 914 debug("getpeername: %.100s", strerror(errno)); 915 cleanup_exit(255); 916 } 917 } 918 919 /* Record that there was a login on that tty from the remote host. */ 920 if (!use_privsep) 921 record_login(pid, s->tty, pw->pw_name, pw->pw_uid, 922 get_remote_name_or_ip(utmp_len, 923 options.use_dns), 924 (struct sockaddr *)&from, fromlen); 925 926#ifdef USE_PAM 927 /* 928 * If password change is needed, do it now. 929 * This needs to occur before the ~/.hushlogin check. 930 */ 931 if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) { 932 display_loginmsg(); 933 do_pam_chauthtok(); 934 s->authctxt->force_pwchange = 0; 935 /* XXX - signal [net] parent to enable forwardings */ 936 } 937#endif 938 939 if (check_quietlogin(s, command)) 940 return; 941 942 display_loginmsg(); 943 944 do_motd(); 945} 946 947/* 948 * Display the message of the day. 949 */ 950void 951do_motd(void) 952{ 953 FILE *f; 954 char buf[256]; 955 956 if (options.print_motd) { 957#ifdef HAVE_LOGIN_CAP 958 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd", 959 "/etc/motd"), "r"); 960#else 961 f = fopen("/etc/motd", "r"); 962#endif 963 if (f) { 964 while (fgets(buf, sizeof(buf), f)) 965 fputs(buf, stdout); 966 fclose(f); 967 } 968 } 969} 970 971 972/* 973 * Check for quiet login, either .hushlogin or command given. 974 */ 975int 976check_quietlogin(Session *s, const char *command) 977{ 978 char buf[256]; 979 struct passwd *pw = s->pw; 980 struct stat st; 981 982 /* Return 1 if .hushlogin exists or a command given. */ 983 if (command != NULL) 984 return 1; 985 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir); 986#ifdef HAVE_LOGIN_CAP 987 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0) 988 return 1; 989#else 990 if (stat(buf, &st) >= 0) 991 return 1; 992#endif 993 return 0; 994} 995 996/* 997 * Sets the value of the given variable in the environment. If the variable 998 * already exists, its value is overridden. 999 */ 1000void 1001child_set_env(char ***envp, u_int *envsizep, const char *name, 1002 const char *value) 1003{ 1004 char **env; 1005 u_int envsize; 1006 u_int i, namelen; 1007 1008 if (strchr(name, '=') != NULL) { 1009 error("Invalid environment variable \"%.100s\"", name); 1010 return; 1011 } 1012 1013 /* 1014 * If we're passed an uninitialized list, allocate a single null 1015 * entry before continuing. 1016 */ 1017 if (*envp == NULL && *envsizep == 0) { 1018 *envp = xmalloc(sizeof(char *)); 1019 *envp[0] = NULL; 1020 *envsizep = 1; 1021 } 1022 1023 /* 1024 * Find the slot where the value should be stored. If the variable 1025 * already exists, we reuse the slot; otherwise we append a new slot 1026 * at the end of the array, expanding if necessary. 1027 */ 1028 env = *envp; 1029 namelen = strlen(name); 1030 for (i = 0; env[i]; i++) 1031 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=') 1032 break; 1033 if (env[i]) { 1034 /* Reuse the slot. */ 1035 free(env[i]); 1036 } else { 1037 /* New variable. Expand if necessary. */ 1038 envsize = *envsizep; 1039 if (i >= envsize - 1) { 1040 if (envsize >= 1000) 1041 fatal("child_set_env: too many env vars"); 1042 envsize += 50; 1043 env = (*envp) = xrealloc(env, envsize, sizeof(char *)); 1044 *envsizep = envsize; 1045 } 1046 /* Need to set the NULL pointer at end of array beyond the new slot. */ 1047 env[i + 1] = NULL; 1048 } 1049 1050 /* Allocate space and format the variable in the appropriate slot. */ 1051 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1); 1052 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value); 1053} 1054 1055/* 1056 * Reads environment variables from the given file and adds/overrides them 1057 * into the environment. If the file does not exist, this does nothing. 1058 * Otherwise, it must consist of empty lines, comments (line starts with '#') 1059 * and assignments of the form name=value. No other forms are allowed. 1060 */ 1061static void 1062read_environment_file(char ***env, u_int *envsize, 1063 const char *filename) 1064{ 1065 FILE *f; 1066 char buf[4096]; 1067 char *cp, *value; 1068 u_int lineno = 0; 1069 1070 f = fopen(filename, "r"); 1071 if (!f) 1072 return; 1073 1074 while (fgets(buf, sizeof(buf), f)) { 1075 if (++lineno > 1000) 1076 fatal("Too many lines in environment file %s", filename); 1077 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++) 1078 ; 1079 if (!*cp || *cp == '#' || *cp == '\n') 1080 continue; 1081 1082 cp[strcspn(cp, "\n")] = '\0'; 1083 1084 value = strchr(cp, '='); 1085 if (value == NULL) { 1086 fprintf(stderr, "Bad line %u in %.100s\n", lineno, 1087 filename); 1088 continue; 1089 } 1090 /* 1091 * Replace the equals sign by nul, and advance value to 1092 * the value string. 1093 */ 1094 *value = '\0'; 1095 value++; 1096 child_set_env(env, envsize, cp, value); 1097 } 1098 fclose(f); 1099} 1100 1101#ifdef HAVE_ETC_DEFAULT_LOGIN 1102/* 1103 * Return named variable from specified environment, or NULL if not present. 1104 */ 1105static char * 1106child_get_env(char **env, const char *name) 1107{ 1108 int i; 1109 size_t len; 1110 1111 len = strlen(name); 1112 for (i=0; env[i] != NULL; i++) 1113 if (strncmp(name, env[i], len) == 0 && env[i][len] == '=') 1114 return(env[i] + len + 1); 1115 return NULL; 1116} 1117 1118/* 1119 * Read /etc/default/login. 1120 * We pick up the PATH (or SUPATH for root) and UMASK. 1121 */ 1122static void 1123read_etc_default_login(char ***env, u_int *envsize, uid_t uid) 1124{ 1125 char **tmpenv = NULL, *var; 1126 u_int i, tmpenvsize = 0; 1127 u_long mask; 1128 1129 /* 1130 * We don't want to copy the whole file to the child's environment, 1131 * so we use a temporary environment and copy the variables we're 1132 * interested in. 1133 */ 1134 read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login"); 1135 1136 if (tmpenv == NULL) 1137 return; 1138 1139 if (uid == 0) 1140 var = child_get_env(tmpenv, "SUPATH"); 1141 else 1142 var = child_get_env(tmpenv, "PATH"); 1143 if (var != NULL) 1144 child_set_env(env, envsize, "PATH", var); 1145 1146 if ((var = child_get_env(tmpenv, "UMASK")) != NULL) 1147 if (sscanf(var, "%5lo", &mask) == 1) 1148 umask((mode_t)mask); 1149 1150 for (i = 0; tmpenv[i] != NULL; i++) 1151 free(tmpenv[i]); 1152 free(tmpenv); 1153} 1154#endif /* HAVE_ETC_DEFAULT_LOGIN */ 1155 1156void 1157copy_environment(char **source, char ***env, u_int *envsize) 1158{ 1159 char *var_name, *var_val; 1160 int i; 1161 1162 if (source == NULL) 1163 return; 1164 1165 for(i = 0; source[i] != NULL; i++) { 1166 var_name = xstrdup(source[i]); 1167 if ((var_val = strstr(var_name, "=")) == NULL) { 1168 free(var_name); 1169 continue; 1170 } 1171 *var_val++ = '\0'; 1172 1173 debug3("Copy environment: %s=%s", var_name, var_val); 1174 child_set_env(env, envsize, var_name, var_val); 1175 1176 free(var_name); 1177 } 1178} 1179 1180static char ** 1181do_setup_env(Session *s, const char *shell) 1182{ 1183 char buf[256]; 1184 u_int i, envsize; 1185 char **env, *laddr; 1186 struct passwd *pw = s->pw; 1187#if !defined (HAVE_LOGIN_CAP) && !defined (HAVE_CYGWIN) 1188 char *path = NULL; 1189#else 1190 extern char **environ; 1191 char **senv, **var; 1192#endif 1193 1194 /* Initialize the environment. */ 1195 envsize = 100; 1196 env = xcalloc(envsize, sizeof(char *)); 1197 env[0] = NULL; 1198 1199#ifdef HAVE_CYGWIN 1200 /* 1201 * The Windows environment contains some setting which are 1202 * important for a running system. They must not be dropped. 1203 */ 1204 { 1205 char **p; 1206 1207 p = fetch_windows_environment(); 1208 copy_environment(p, &env, &envsize); 1209 free_windows_environment(p); 1210 } 1211#endif 1212 1213 if (getenv("TZ")) 1214 child_set_env(&env, &envsize, "TZ", getenv("TZ")); 1215 1216#ifdef GSSAPI 1217 /* Allow any GSSAPI methods that we've used to alter 1218 * the childs environment as they see fit 1219 */ 1220 ssh_gssapi_do_child(&env, &envsize); 1221#endif 1222 1223 if (!options.use_login) { 1224 /* Set basic environment. */ 1225 for (i = 0; i < s->num_env; i++) 1226 child_set_env(&env, &envsize, s->env[i].name, 1227 s->env[i].val); 1228 1229 child_set_env(&env, &envsize, "USER", pw->pw_name); 1230 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name); 1231#ifdef _AIX 1232 child_set_env(&env, &envsize, "LOGIN", pw->pw_name); 1233#endif 1234 child_set_env(&env, &envsize, "HOME", pw->pw_dir); 1235 snprintf(buf, sizeof buf, "%.200s/%.50s", 1236 _PATH_MAILDIR, pw->pw_name); 1237 child_set_env(&env, &envsize, "MAIL", buf); 1238#ifdef HAVE_LOGIN_CAP 1239 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH); 1240 child_set_env(&env, &envsize, "TERM", "su"); 1241 senv = environ; 1242 environ = xmalloc(sizeof(char *)); 1243 *environ = NULL; 1244 (void) setusercontext(lc, pw, pw->pw_uid, 1245 LOGIN_SETENV|LOGIN_SETPATH); 1246 copy_environment(environ, &env, &envsize); 1247 for (var = environ; *var != NULL; ++var) 1248 free(*var); 1249 free(environ); 1250 environ = senv; 1251#else /* HAVE_LOGIN_CAP */ 1252# ifndef HAVE_CYGWIN 1253 /* 1254 * There's no standard path on Windows. The path contains 1255 * important components pointing to the system directories, 1256 * needed for loading shared libraries. So the path better 1257 * remains intact here. 1258 */ 1259# ifdef HAVE_ETC_DEFAULT_LOGIN 1260 read_etc_default_login(&env, &envsize, pw->pw_uid); 1261 path = child_get_env(env, "PATH"); 1262# endif /* HAVE_ETC_DEFAULT_LOGIN */ 1263 if (path == NULL || *path == '\0') { 1264 child_set_env(&env, &envsize, "PATH", 1265 s->pw->pw_uid == 0 ? 1266 SUPERUSER_PATH : _PATH_STDPATH); 1267 } 1268# endif /* HAVE_CYGWIN */ 1269#endif /* HAVE_LOGIN_CAP */ 1270 1271 /* Normal systems set SHELL by default. */ 1272 child_set_env(&env, &envsize, "SHELL", shell); 1273 } 1274 1275 /* Set custom environment options from RSA authentication. */ 1276 if (!options.use_login) { 1277 while (custom_environment) { 1278 struct envstring *ce = custom_environment; 1279 char *str = ce->s; 1280 1281 for (i = 0; str[i] != '=' && str[i]; i++) 1282 ; 1283 if (str[i] == '=') { 1284 str[i] = 0; 1285 child_set_env(&env, &envsize, str, str + i + 1); 1286 } 1287 custom_environment = ce->next; 1288 free(ce->s); 1289 free(ce); 1290 } 1291 } 1292 1293 /* SSH_CLIENT deprecated */ 1294 snprintf(buf, sizeof buf, "%.50s %d %d", 1295 get_remote_ipaddr(), get_remote_port(), get_local_port()); 1296 child_set_env(&env, &envsize, "SSH_CLIENT", buf); 1297 1298 laddr = get_local_ipaddr(packet_get_connection_in()); 1299 snprintf(buf, sizeof buf, "%.50s %d %.50s %d", 1300 get_remote_ipaddr(), get_remote_port(), laddr, get_local_port()); 1301 free(laddr); 1302 child_set_env(&env, &envsize, "SSH_CONNECTION", buf); 1303 1304 if (s->ttyfd != -1) 1305 child_set_env(&env, &envsize, "SSH_TTY", s->tty); 1306 if (s->term) 1307 child_set_env(&env, &envsize, "TERM", s->term); 1308 if (s->display) 1309 child_set_env(&env, &envsize, "DISPLAY", s->display); 1310 if (original_command) 1311 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND", 1312 original_command); 1313 1314#ifdef _UNICOS 1315 if (cray_tmpdir[0] != '\0') 1316 child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir); 1317#endif /* _UNICOS */ 1318 1319 /* 1320 * Since we clear KRB5CCNAME at startup, if it's set now then it 1321 * must have been set by a native authentication method (eg AIX or 1322 * SIA), so copy it to the child. 1323 */ 1324 { 1325 char *cp; 1326 1327 if ((cp = getenv("KRB5CCNAME")) != NULL) 1328 child_set_env(&env, &envsize, "KRB5CCNAME", cp); 1329 } 1330 1331#ifdef _AIX 1332 { 1333 char *cp; 1334 1335 if ((cp = getenv("AUTHSTATE")) != NULL) 1336 child_set_env(&env, &envsize, "AUTHSTATE", cp); 1337 read_environment_file(&env, &envsize, "/etc/environment"); 1338 } 1339#endif 1340#ifdef KRB5 1341 if (s->authctxt->krb5_ccname) 1342 child_set_env(&env, &envsize, "KRB5CCNAME", 1343 s->authctxt->krb5_ccname); 1344#endif 1345#ifdef USE_PAM 1346 /* 1347 * Pull in any environment variables that may have 1348 * been set by PAM. 1349 */ 1350 if (options.use_pam) { 1351 char **p; 1352 1353 p = fetch_pam_child_environment(); 1354 copy_environment(p, &env, &envsize); 1355 free_pam_environment(p); 1356 1357 p = fetch_pam_environment(); 1358 copy_environment(p, &env, &envsize); 1359 free_pam_environment(p); 1360 } 1361#endif /* USE_PAM */ 1362 1363 if (auth_sock_name != NULL) 1364 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME, 1365 auth_sock_name); 1366 1367 /* read $HOME/.ssh/environment. */ 1368 if (options.permit_user_env && !options.use_login) { 1369 snprintf(buf, sizeof buf, "%.200s/.ssh/environment", 1370 strcmp(pw->pw_dir, "/") ? pw->pw_dir : ""); 1371 read_environment_file(&env, &envsize, buf); 1372 } 1373 if (debug_flag) { 1374 /* dump the environment */ 1375 fprintf(stderr, "Environment:\n"); 1376 for (i = 0; env[i]; i++) 1377 fprintf(stderr, " %.200s\n", env[i]); 1378 } 1379 return env; 1380} 1381 1382/* 1383 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found 1384 * first in this order). 1385 */ 1386static void 1387do_rc_files(Session *s, const char *shell) 1388{ 1389 FILE *f = NULL; 1390 char cmd[1024]; 1391 int do_xauth; 1392 struct stat st; 1393 1394 do_xauth = 1395 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL; 1396 1397 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */ 1398 if (!s->is_subsystem && options.adm_forced_command == NULL && 1399 !no_user_rc && stat(_PATH_SSH_USER_RC, &st) >= 0) { 1400 snprintf(cmd, sizeof cmd, "%s -c '%s %s'", 1401 shell, _PATH_BSHELL, _PATH_SSH_USER_RC); 1402 if (debug_flag) 1403 fprintf(stderr, "Running %s\n", cmd); 1404 f = popen(cmd, "w"); 1405 if (f) { 1406 if (do_xauth) 1407 fprintf(f, "%s %s\n", s->auth_proto, 1408 s->auth_data); 1409 pclose(f); 1410 } else 1411 fprintf(stderr, "Could not run %s\n", 1412 _PATH_SSH_USER_RC); 1413 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) { 1414 if (debug_flag) 1415 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL, 1416 _PATH_SSH_SYSTEM_RC); 1417 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w"); 1418 if (f) { 1419 if (do_xauth) 1420 fprintf(f, "%s %s\n", s->auth_proto, 1421 s->auth_data); 1422 pclose(f); 1423 } else 1424 fprintf(stderr, "Could not run %s\n", 1425 _PATH_SSH_SYSTEM_RC); 1426 } else if (do_xauth && options.xauth_location != NULL) { 1427 /* Add authority data to .Xauthority if appropriate. */ 1428 if (debug_flag) { 1429 fprintf(stderr, 1430 "Running %.500s remove %.100s\n", 1431 options.xauth_location, s->auth_display); 1432 fprintf(stderr, 1433 "%.500s add %.100s %.100s %.100s\n", 1434 options.xauth_location, s->auth_display, 1435 s->auth_proto, s->auth_data); 1436 } 1437 snprintf(cmd, sizeof cmd, "%s -q -", 1438 options.xauth_location); 1439 f = popen(cmd, "w"); 1440 if (f) { 1441 fprintf(f, "remove %s\n", 1442 s->auth_display); 1443 fprintf(f, "add %s %s %s\n", 1444 s->auth_display, s->auth_proto, 1445 s->auth_data); 1446 pclose(f); 1447 } else { 1448 fprintf(stderr, "Could not run %s\n", 1449 cmd); 1450 } 1451 } 1452} 1453 1454static void 1455do_nologin(struct passwd *pw) 1456{ 1457 FILE *f = NULL; 1458 char buf[1024], *nl, *def_nl = _PATH_NOLOGIN; 1459 struct stat sb; 1460 1461#ifdef HAVE_LOGIN_CAP 1462 if (login_getcapbool(lc, "ignorenologin", 0) || pw->pw_uid == 0) 1463 return; 1464 nl = login_getcapstr(lc, "nologin", def_nl, def_nl); 1465#else 1466 if (pw->pw_uid == 0) 1467 return; 1468 nl = def_nl; 1469#endif 1470 if (stat(nl, &sb) == -1) { 1471 if (nl != def_nl) 1472 free(nl); 1473 return; 1474 } 1475 1476 /* /etc/nologin exists. Print its contents if we can and exit. */ 1477 logit("User %.100s not allowed because %s exists", pw->pw_name, nl); 1478 if ((f = fopen(nl, "r")) != NULL) { 1479 while (fgets(buf, sizeof(buf), f)) 1480 fputs(buf, stderr); 1481 fclose(f); 1482 } 1483 exit(254); 1484} 1485 1486/* 1487 * Chroot into a directory after checking it for safety: all path components 1488 * must be root-owned directories with strict permissions. 1489 */ 1490static void 1491safely_chroot(const char *path, uid_t uid) 1492{ 1493 const char *cp; 1494 char component[MAXPATHLEN]; 1495 struct stat st; 1496 1497 if (*path != '/') 1498 fatal("chroot path does not begin at root"); 1499 if (strlen(path) >= sizeof(component)) 1500 fatal("chroot path too long"); 1501 1502 /* 1503 * Descend the path, checking that each component is a 1504 * root-owned directory with strict permissions. 1505 */ 1506 for (cp = path; cp != NULL;) { 1507 if ((cp = strchr(cp, '/')) == NULL) 1508 strlcpy(component, path, sizeof(component)); 1509 else { 1510 cp++; 1511 memcpy(component, path, cp - path); 1512 component[cp - path] = '\0'; 1513 } 1514 1515 debug3("%s: checking '%s'", __func__, component); 1516 1517 if (stat(component, &st) != 0) 1518 fatal("%s: stat(\"%s\"): %s", __func__, 1519 component, strerror(errno)); 1520 if (st.st_uid != 0 || (st.st_mode & 022) != 0) 1521 fatal("bad ownership or modes for chroot " 1522 "directory %s\"%s\"", 1523 cp == NULL ? "" : "component ", component); 1524 if (!S_ISDIR(st.st_mode)) 1525 fatal("chroot path %s\"%s\" is not a directory", 1526 cp == NULL ? "" : "component ", component); 1527 1528 } 1529 1530 if (chdir(path) == -1) 1531 fatal("Unable to chdir to chroot path \"%s\": " 1532 "%s", path, strerror(errno)); 1533 if (chroot(path) == -1) 1534 fatal("chroot(\"%s\"): %s", path, strerror(errno)); 1535 if (chdir("/") == -1) 1536 fatal("%s: chdir(/) after chroot: %s", 1537 __func__, strerror(errno)); 1538 verbose("Changed root directory to \"%s\"", path); 1539} 1540 1541/* Set login name, uid, gid, and groups. */ 1542void 1543do_setusercontext(struct passwd *pw) 1544{ 1545 char *chroot_path, *tmp; 1546 1547 platform_setusercontext(pw); 1548 1549 if (platform_privileged_uidswap()) { 1550#ifdef HAVE_LOGIN_CAP 1551 if (setusercontext(lc, pw, pw->pw_uid, 1552 (LOGIN_SETALL & ~(LOGIN_SETENV|LOGIN_SETPATH|LOGIN_SETUSER))) < 0) { 1553 perror("unable to set user context"); 1554 exit(1); 1555 } 1556#else 1557 if (setlogin(pw->pw_name) < 0) 1558 error("setlogin failed: %s", strerror(errno)); 1559 if (setgid(pw->pw_gid) < 0) { 1560 perror("setgid"); 1561 exit(1); 1562 } 1563 /* Initialize the group list. */ 1564 if (initgroups(pw->pw_name, pw->pw_gid) < 0) { 1565 perror("initgroups"); 1566 exit(1); 1567 } 1568 endgrent(); 1569#endif 1570 1571 platform_setusercontext_post_groups(pw); 1572 1573 if (options.chroot_directory != NULL && 1574 strcasecmp(options.chroot_directory, "none") != 0) { 1575 tmp = tilde_expand_filename(options.chroot_directory, 1576 pw->pw_uid); 1577 chroot_path = percent_expand(tmp, "h", pw->pw_dir, 1578 "u", pw->pw_name, (char *)NULL); 1579 safely_chroot(chroot_path, pw->pw_uid); 1580 free(tmp); 1581 free(chroot_path); 1582 /* Make sure we don't attempt to chroot again */ 1583 free(options.chroot_directory); 1584 options.chroot_directory = NULL; 1585 } 1586 1587#ifdef HAVE_LOGIN_CAP 1588 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) { 1589 perror("unable to set user context (setuser)"); 1590 exit(1); 1591 } 1592 /* 1593 * FreeBSD's setusercontext() will not apply the user's 1594 * own umask setting unless running with the user's UID. 1595 */ 1596 (void) setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUMASK); 1597#else 1598# ifdef USE_LIBIAF 1599 if (set_id(pw->pw_name) != 0) { 1600 fatal("set_id(%s) Failed", pw->pw_name); 1601 } 1602# endif /* USE_LIBIAF */ 1603 /* Permanently switch to the desired uid. */ 1604 permanently_set_uid(pw); 1605#endif 1606 } else if (options.chroot_directory != NULL && 1607 strcasecmp(options.chroot_directory, "none") != 0) { 1608 fatal("server lacks privileges to chroot to ChrootDirectory"); 1609 } 1610 1611 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid) 1612 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid); 1613} 1614 1615static void 1616do_pwchange(Session *s) 1617{ 1618 fflush(NULL); 1619 fprintf(stderr, "WARNING: Your password has expired.\n"); 1620 if (s->ttyfd != -1) { 1621 fprintf(stderr, 1622 "You must change your password now and login again!\n"); 1623#ifdef WITH_SELINUX 1624 setexeccon(NULL); 1625#endif 1626#ifdef PASSWD_NEEDS_USERNAME 1627 execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name, 1628 (char *)NULL); 1629#else 1630 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL); 1631#endif 1632 perror("passwd"); 1633 } else { 1634 fprintf(stderr, 1635 "Password change required but no TTY available.\n"); 1636 } 1637 exit(1); 1638} 1639 1640static void 1641launch_login(struct passwd *pw, const char *hostname) 1642{ 1643 /* Launch login(1). */ 1644 1645 execl(LOGIN_PROGRAM, "login", "-h", hostname, 1646#ifdef xxxLOGIN_NEEDS_TERM 1647 (s->term ? s->term : "unknown"), 1648#endif /* LOGIN_NEEDS_TERM */ 1649#ifdef LOGIN_NO_ENDOPT 1650 "-p", "-f", pw->pw_name, (char *)NULL); 1651#else 1652 "-p", "-f", "--", pw->pw_name, (char *)NULL); 1653#endif 1654 1655 /* Login couldn't be executed, die. */ 1656 1657 perror("login"); 1658 exit(1); 1659} 1660 1661static void 1662child_close_fds(void) 1663{ 1664 extern AuthenticationConnection *auth_conn; 1665 1666 if (auth_conn) { 1667 ssh_close_authentication_connection(auth_conn); 1668 auth_conn = NULL; 1669 } 1670 1671 if (packet_get_connection_in() == packet_get_connection_out()) 1672 close(packet_get_connection_in()); 1673 else { 1674 close(packet_get_connection_in()); 1675 close(packet_get_connection_out()); 1676 } 1677 /* 1678 * Close all descriptors related to channels. They will still remain 1679 * open in the parent. 1680 */ 1681 /* XXX better use close-on-exec? -markus */ 1682 channel_close_all(); 1683 1684 /* 1685 * Close any extra file descriptors. Note that there may still be 1686 * descriptors left by system functions. They will be closed later. 1687 */ 1688 endpwent(); 1689 1690 /* 1691 * Close any extra open file descriptors so that we don't have them 1692 * hanging around in clients. Note that we want to do this after 1693 * initgroups, because at least on Solaris 2.3 it leaves file 1694 * descriptors open. 1695 */ 1696 closefrom(STDERR_FILENO + 1); 1697} 1698 1699/* 1700 * Performs common processing for the child, such as setting up the 1701 * environment, closing extra file descriptors, setting the user and group 1702 * ids, and executing the command or shell. 1703 */ 1704#define ARGV_MAX 10 1705void 1706do_child(Session *s, const char *command) 1707{ 1708 extern char **environ; 1709 char **env; 1710 char *argv[ARGV_MAX]; 1711 const char *shell, *shell0, *hostname = NULL; 1712 struct passwd *pw = s->pw; 1713 int r = 0; 1714 1715 /* remove hostkey from the child's memory */ 1716 destroy_sensitive_data(); 1717 1718 /* Force a password change */ 1719 if (s->authctxt->force_pwchange) { 1720 do_setusercontext(pw); 1721 child_close_fds(); 1722 do_pwchange(s); 1723 exit(1); 1724 } 1725 1726 /* login(1) is only called if we execute the login shell */ 1727 if (options.use_login && command != NULL) 1728 options.use_login = 0; 1729 1730#ifdef _UNICOS 1731 cray_setup(pw->pw_uid, pw->pw_name, command); 1732#endif /* _UNICOS */ 1733 1734 /* 1735 * Login(1) does this as well, and it needs uid 0 for the "-h" 1736 * switch, so we let login(1) to this for us. 1737 */ 1738 if (!options.use_login) { 1739#ifdef HAVE_OSF_SIA 1740 session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty); 1741 if (!check_quietlogin(s, command)) 1742 do_motd(); 1743#else /* HAVE_OSF_SIA */ 1744 /* When PAM is enabled we rely on it to do the nologin check */ 1745 if (!options.use_pam) 1746 do_nologin(pw); 1747 do_setusercontext(pw); 1748 /* 1749 * PAM session modules in do_setusercontext may have 1750 * generated messages, so if this in an interactive 1751 * login then display them too. 1752 */ 1753 if (!check_quietlogin(s, command)) 1754 display_loginmsg(); 1755#endif /* HAVE_OSF_SIA */ 1756 } 1757 1758#ifdef USE_PAM 1759 if (options.use_pam && !options.use_login && !is_pam_session_open()) { 1760 debug3("PAM session not opened, exiting"); 1761 display_loginmsg(); 1762 exit(254); 1763 } 1764#endif 1765 1766 /* 1767 * Get the shell from the password data. An empty shell field is 1768 * legal, and means /bin/sh. 1769 */ 1770 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell; 1771 1772 /* 1773 * Make sure $SHELL points to the shell from the password file, 1774 * even if shell is overridden from login.conf 1775 */ 1776 env = do_setup_env(s, shell); 1777 1778#ifdef HAVE_LOGIN_CAP 1779 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell); 1780#endif 1781 1782 /* we have to stash the hostname before we close our socket. */ 1783 if (options.use_login) 1784 hostname = get_remote_name_or_ip(utmp_len, 1785 options.use_dns); 1786 /* 1787 * Close the connection descriptors; note that this is the child, and 1788 * the server will still have the socket open, and it is important 1789 * that we do not shutdown it. Note that the descriptors cannot be 1790 * closed before building the environment, as we call 1791 * get_remote_ipaddr there. 1792 */ 1793 child_close_fds(); 1794 1795 /* 1796 * Must take new environment into use so that .ssh/rc, 1797 * /etc/ssh/sshrc and xauth are run in the proper environment. 1798 */ 1799 environ = env; 1800 1801#if defined(KRB5) && defined(USE_AFS) 1802 /* 1803 * At this point, we check to see if AFS is active and if we have 1804 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see 1805 * if we can (and need to) extend the ticket into an AFS token. If 1806 * we don't do this, we run into potential problems if the user's 1807 * home directory is in AFS and it's not world-readable. 1808 */ 1809 1810 if (options.kerberos_get_afs_token && k_hasafs() && 1811 (s->authctxt->krb5_ctx != NULL)) { 1812 char cell[64]; 1813 1814 debug("Getting AFS token"); 1815 1816 k_setpag(); 1817 1818 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0) 1819 krb5_afslog(s->authctxt->krb5_ctx, 1820 s->authctxt->krb5_fwd_ccache, cell, NULL); 1821 1822 krb5_afslog_home(s->authctxt->krb5_ctx, 1823 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir); 1824 } 1825#endif 1826 1827 /* Change current directory to the user's home directory. */ 1828 if (chdir(pw->pw_dir) < 0) { 1829 /* Suppress missing homedir warning for chroot case */ 1830#ifdef HAVE_LOGIN_CAP 1831 r = login_getcapbool(lc, "requirehome", 0); 1832#endif 1833 if (r || options.chroot_directory == NULL || 1834 strcasecmp(options.chroot_directory, "none") == 0) 1835 fprintf(stderr, "Could not chdir to home " 1836 "directory %s: %s\n", pw->pw_dir, 1837 strerror(errno)); 1838 if (r) 1839 exit(1); 1840 } 1841 1842 closefrom(STDERR_FILENO + 1); 1843 1844 if (!options.use_login) 1845 do_rc_files(s, shell); 1846 1847 /* restore SIGPIPE for child */ 1848 signal(SIGPIPE, SIG_DFL); 1849 1850 if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) { 1851 printf("This service allows sftp connections only.\n"); 1852 fflush(NULL); 1853 exit(1); 1854 } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) { 1855 extern int optind, optreset; 1856 int i; 1857 char *p, *args; 1858 1859 setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME); 1860 args = xstrdup(command ? command : "sftp-server"); 1861 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " "))) 1862 if (i < ARGV_MAX - 1) 1863 argv[i++] = p; 1864 argv[i] = NULL; 1865 optind = optreset = 1; 1866 __progname = argv[0]; 1867#ifdef WITH_SELINUX 1868 ssh_selinux_change_context("sftpd_t"); 1869#endif 1870 exit(sftp_server_main(i, argv, s->pw)); 1871 } 1872 1873 fflush(NULL); 1874 1875 if (options.use_login) { 1876 launch_login(pw, hostname); 1877 /* NEVERREACHED */ 1878 } 1879 1880 /* Get the last component of the shell name. */ 1881 if ((shell0 = strrchr(shell, '/')) != NULL) 1882 shell0++; 1883 else 1884 shell0 = shell; 1885 1886 /* 1887 * If we have no command, execute the shell. In this case, the shell 1888 * name to be passed in argv[0] is preceded by '-' to indicate that 1889 * this is a login shell. 1890 */ 1891 if (!command) { 1892 char argv0[256]; 1893 1894 /* Start the shell. Set initial character to '-'. */ 1895 argv0[0] = '-'; 1896 1897 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1) 1898 >= sizeof(argv0) - 1) { 1899 errno = EINVAL; 1900 perror(shell); 1901 exit(1); 1902 } 1903 1904 /* Execute the shell. */ 1905 argv[0] = argv0; 1906 argv[1] = NULL; 1907 execve(shell, argv, env); 1908 1909 /* Executing the shell failed. */ 1910 perror(shell); 1911 exit(1); 1912 } 1913 /* 1914 * Execute the command using the user's shell. This uses the -c 1915 * option to execute the command. 1916 */ 1917 argv[0] = (char *) shell0; 1918 argv[1] = "-c"; 1919 argv[2] = (char *) command; 1920 argv[3] = NULL; 1921 execve(shell, argv, env); 1922 perror(shell); 1923 exit(1); 1924} 1925 1926void 1927session_unused(int id) 1928{ 1929 debug3("%s: session id %d unused", __func__, id); 1930 if (id >= options.max_sessions || 1931 id >= sessions_nalloc) { 1932 fatal("%s: insane session id %d (max %d nalloc %d)", 1933 __func__, id, options.max_sessions, sessions_nalloc); 1934 } 1935 memset(&sessions[id], 0, sizeof(*sessions)); 1936 sessions[id].self = id; 1937 sessions[id].used = 0; 1938 sessions[id].chanid = -1; 1939 sessions[id].ptyfd = -1; 1940 sessions[id].ttyfd = -1; 1941 sessions[id].ptymaster = -1; 1942 sessions[id].x11_chanids = NULL; 1943 sessions[id].next_unused = sessions_first_unused; 1944 sessions_first_unused = id; 1945} 1946 1947Session * 1948session_new(void) 1949{ 1950 Session *s, *tmp; 1951 1952 if (sessions_first_unused == -1) { 1953 if (sessions_nalloc >= options.max_sessions) 1954 return NULL; 1955 debug2("%s: allocate (allocated %d max %d)", 1956 __func__, sessions_nalloc, options.max_sessions); 1957 tmp = xrealloc(sessions, sessions_nalloc + 1, 1958 sizeof(*sessions)); 1959 if (tmp == NULL) { 1960 error("%s: cannot allocate %d sessions", 1961 __func__, sessions_nalloc + 1); 1962 return NULL; 1963 } 1964 sessions = tmp; 1965 session_unused(sessions_nalloc++); 1966 } 1967 1968 if (sessions_first_unused >= sessions_nalloc || 1969 sessions_first_unused < 0) { 1970 fatal("%s: insane first_unused %d max %d nalloc %d", 1971 __func__, sessions_first_unused, options.max_sessions, 1972 sessions_nalloc); 1973 } 1974 1975 s = &sessions[sessions_first_unused]; 1976 if (s->used) { 1977 fatal("%s: session %d already used", 1978 __func__, sessions_first_unused); 1979 } 1980 sessions_first_unused = s->next_unused; 1981 s->used = 1; 1982 s->next_unused = -1; 1983 debug("session_new: session %d", s->self); 1984 1985 return s; 1986} 1987 1988static void 1989session_dump(void) 1990{ 1991 int i; 1992 for (i = 0; i < sessions_nalloc; i++) { 1993 Session *s = &sessions[i]; 1994 1995 debug("dump: used %d next_unused %d session %d %p " 1996 "channel %d pid %ld", 1997 s->used, 1998 s->next_unused, 1999 s->self, 2000 s, 2001 s->chanid, 2002 (long)s->pid); 2003 } 2004} 2005 2006int 2007session_open(Authctxt *authctxt, int chanid) 2008{ 2009 Session *s = session_new(); 2010 debug("session_open: channel %d", chanid); 2011 if (s == NULL) { 2012 error("no more sessions"); 2013 return 0; 2014 } 2015 s->authctxt = authctxt; 2016 s->pw = authctxt->pw; 2017 if (s->pw == NULL || !authctxt->valid) 2018 fatal("no user for session %d", s->self); 2019 debug("session_open: session %d: link with channel %d", s->self, chanid); 2020 s->chanid = chanid; 2021 return 1; 2022} 2023 2024Session * 2025session_by_tty(char *tty) 2026{ 2027 int i; 2028 for (i = 0; i < sessions_nalloc; i++) { 2029 Session *s = &sessions[i]; 2030 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) { 2031 debug("session_by_tty: session %d tty %s", i, tty); 2032 return s; 2033 } 2034 } 2035 debug("session_by_tty: unknown tty %.100s", tty); 2036 session_dump(); 2037 return NULL; 2038} 2039 2040static Session * 2041session_by_channel(int id) 2042{ 2043 int i; 2044 for (i = 0; i < sessions_nalloc; i++) { 2045 Session *s = &sessions[i]; 2046 if (s->used && s->chanid == id) { 2047 debug("session_by_channel: session %d channel %d", 2048 i, id); 2049 return s; 2050 } 2051 } 2052 debug("session_by_channel: unknown channel %d", id); 2053 session_dump(); 2054 return NULL; 2055} 2056 2057static Session * 2058session_by_x11_channel(int id) 2059{ 2060 int i, j; 2061 2062 for (i = 0; i < sessions_nalloc; i++) { 2063 Session *s = &sessions[i]; 2064 2065 if (s->x11_chanids == NULL || !s->used) 2066 continue; 2067 for (j = 0; s->x11_chanids[j] != -1; j++) { 2068 if (s->x11_chanids[j] == id) { 2069 debug("session_by_x11_channel: session %d " 2070 "channel %d", s->self, id); 2071 return s; 2072 } 2073 } 2074 } 2075 debug("session_by_x11_channel: unknown channel %d", id); 2076 session_dump(); 2077 return NULL; 2078} 2079 2080static Session * 2081session_by_pid(pid_t pid) 2082{ 2083 int i; 2084 debug("session_by_pid: pid %ld", (long)pid); 2085 for (i = 0; i < sessions_nalloc; i++) { 2086 Session *s = &sessions[i]; 2087 if (s->used && s->pid == pid) 2088 return s; 2089 } 2090 error("session_by_pid: unknown pid %ld", (long)pid); 2091 session_dump(); 2092 return NULL; 2093} 2094 2095static int 2096session_window_change_req(Session *s) 2097{ 2098 s->col = packet_get_int(); 2099 s->row = packet_get_int(); 2100 s->xpixel = packet_get_int(); 2101 s->ypixel = packet_get_int(); 2102 packet_check_eom(); 2103 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel); 2104 return 1; 2105} 2106 2107static int 2108session_pty_req(Session *s) 2109{ 2110 u_int len; 2111 int n_bytes; 2112 2113 if (no_pty_flag || !options.permit_tty) { 2114 debug("Allocating a pty not permitted for this authentication."); 2115 return 0; 2116 } 2117 if (s->ttyfd != -1) { 2118 packet_disconnect("Protocol error: you already have a pty."); 2119 return 0; 2120 } 2121 2122 s->term = packet_get_string(&len); 2123 2124 if (compat20) { 2125 s->col = packet_get_int(); 2126 s->row = packet_get_int(); 2127 } else { 2128 s->row = packet_get_int(); 2129 s->col = packet_get_int(); 2130 } 2131 s->xpixel = packet_get_int(); 2132 s->ypixel = packet_get_int(); 2133 2134 if (strcmp(s->term, "") == 0) { 2135 free(s->term); 2136 s->term = NULL; 2137 } 2138 2139 /* Allocate a pty and open it. */ 2140 debug("Allocating pty."); 2141 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, 2142 sizeof(s->tty)))) { 2143 free(s->term); 2144 s->term = NULL; 2145 s->ptyfd = -1; 2146 s->ttyfd = -1; 2147 error("session_pty_req: session %d alloc failed", s->self); 2148 return 0; 2149 } 2150 debug("session_pty_req: session %d alloc %s", s->self, s->tty); 2151 2152 /* for SSH1 the tty modes length is not given */ 2153 if (!compat20) 2154 n_bytes = packet_remaining(); 2155 tty_parse_modes(s->ttyfd, &n_bytes); 2156 2157 if (!use_privsep) 2158 pty_setowner(s->pw, s->tty); 2159 2160 /* Set window size from the packet. */ 2161 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel); 2162 2163 packet_check_eom(); 2164 session_proctitle(s); 2165 return 1; 2166} 2167 2168static int 2169session_subsystem_req(Session *s) 2170{ 2171 struct stat st; 2172 u_int len; 2173 int success = 0; 2174 char *prog, *cmd; 2175 u_int i; 2176 2177 s->subsys = packet_get_string(&len); 2178 packet_check_eom(); 2179 debug2("subsystem request for %.100s by user %s", s->subsys, 2180 s->pw->pw_name); 2181 2182 for (i = 0; i < options.num_subsystems; i++) { 2183 if (strcmp(s->subsys, options.subsystem_name[i]) == 0) { 2184 prog = options.subsystem_command[i]; 2185 cmd = options.subsystem_args[i]; 2186 if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) { 2187 s->is_subsystem = SUBSYSTEM_INT_SFTP; 2188 debug("subsystem: %s", prog); 2189 } else { 2190 if (stat(prog, &st) < 0) 2191 debug("subsystem: cannot stat %s: %s", 2192 prog, strerror(errno)); 2193 s->is_subsystem = SUBSYSTEM_EXT; 2194 debug("subsystem: exec() %s", cmd); 2195 } 2196 success = do_exec(s, cmd) == 0; 2197 break; 2198 } 2199 } 2200 2201 if (!success) 2202 logit("subsystem request for %.100s by user %s failed, " 2203 "subsystem not found", s->subsys, s->pw->pw_name); 2204 2205 return success; 2206} 2207 2208static int 2209session_x11_req(Session *s) 2210{ 2211 int success; 2212 2213 if (s->auth_proto != NULL || s->auth_data != NULL) { 2214 error("session_x11_req: session %d: " 2215 "x11 forwarding already active", s->self); 2216 return 0; 2217 } 2218 s->single_connection = packet_get_char(); 2219 s->auth_proto = packet_get_string(NULL); 2220 s->auth_data = packet_get_string(NULL); 2221 s->screen = packet_get_int(); 2222 packet_check_eom(); 2223 2224 if (xauth_valid_string(s->auth_proto) && 2225 xauth_valid_string(s->auth_data)) 2226 success = session_setup_x11fwd(s); 2227 else { 2228 success = 0; 2229 error("Invalid X11 forwarding data"); 2230 } 2231 if (!success) { 2232 free(s->auth_proto); 2233 free(s->auth_data); 2234 s->auth_proto = NULL; 2235 s->auth_data = NULL; 2236 } 2237 return success; 2238} 2239 2240static int 2241session_shell_req(Session *s) 2242{ 2243 packet_check_eom(); 2244 return do_exec(s, NULL) == 0; 2245} 2246 2247static int 2248session_exec_req(Session *s) 2249{ 2250 u_int len, success; 2251 2252 char *command = packet_get_string(&len); 2253 packet_check_eom(); 2254 success = do_exec(s, command) == 0; 2255 free(command); 2256 return success; 2257} 2258 2259static int 2260session_break_req(Session *s) 2261{ 2262 2263 packet_get_int(); /* ignored */ 2264 packet_check_eom(); 2265 2266 if (s->ptymaster == -1 || tcsendbreak(s->ptymaster, 0) < 0) 2267 return 0; 2268 return 1; 2269} 2270 2271static int 2272session_env_req(Session *s) 2273{ 2274 char *name, *val; 2275 u_int name_len, val_len, i; 2276 2277 name = packet_get_cstring(&name_len); 2278 val = packet_get_cstring(&val_len); 2279 packet_check_eom(); 2280 2281 /* Don't set too many environment variables */ 2282 if (s->num_env > 128) { 2283 debug2("Ignoring env request %s: too many env vars", name); 2284 goto fail; 2285 } 2286 2287 for (i = 0; i < options.num_accept_env; i++) { 2288 if (match_pattern(name, options.accept_env[i])) { 2289 debug2("Setting env %d: %s=%s", s->num_env, name, val); 2290 s->env = xrealloc(s->env, s->num_env + 1, 2291 sizeof(*s->env)); 2292 s->env[s->num_env].name = name; 2293 s->env[s->num_env].val = val; 2294 s->num_env++; 2295 return (1); 2296 } 2297 } 2298 debug2("Ignoring env request %s: disallowed name", name); 2299 2300 fail: 2301 free(name); 2302 free(val); 2303 return (0); 2304} 2305 2306static int 2307session_auth_agent_req(Session *s) 2308{ 2309 static int called = 0; 2310 packet_check_eom(); 2311 if (no_agent_forwarding_flag || !options.allow_agent_forwarding) { 2312 debug("session_auth_agent_req: no_agent_forwarding_flag"); 2313 return 0; 2314 } 2315 if (called) { 2316 return 0; 2317 } else { 2318 called = 1; 2319 return auth_input_request_forwarding(s->pw); 2320 } 2321} 2322 2323int 2324session_input_channel_req(Channel *c, const char *rtype) 2325{ 2326 int success = 0; 2327 Session *s; 2328 2329 if ((s = session_by_channel(c->self)) == NULL) { 2330 logit("session_input_channel_req: no session %d req %.100s", 2331 c->self, rtype); 2332 return 0; 2333 } 2334 debug("session_input_channel_req: session %d req %s", s->self, rtype); 2335 2336 /* 2337 * a session is in LARVAL state until a shell, a command 2338 * or a subsystem is executed 2339 */ 2340 if (c->type == SSH_CHANNEL_LARVAL) { 2341 if (strcmp(rtype, "shell") == 0) { 2342 success = session_shell_req(s); 2343 } else if (strcmp(rtype, "exec") == 0) { 2344 success = session_exec_req(s); 2345 } else if (strcmp(rtype, "pty-req") == 0) { 2346 success = session_pty_req(s); 2347 } else if (strcmp(rtype, "x11-req") == 0) { 2348 success = session_x11_req(s); 2349 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) { 2350 success = session_auth_agent_req(s); 2351 } else if (strcmp(rtype, "subsystem") == 0) { 2352 success = session_subsystem_req(s); 2353 } else if (strcmp(rtype, "env") == 0) { 2354 success = session_env_req(s); 2355 } 2356 } 2357 if (strcmp(rtype, "window-change") == 0) { 2358 success = session_window_change_req(s); 2359 } else if (strcmp(rtype, "break") == 0) { 2360 success = session_break_req(s); 2361 } 2362 2363 return success; 2364} 2365 2366void 2367session_set_fds(Session *s, int fdin, int fdout, int fderr, int ignore_fderr, 2368 int is_tty) 2369{ 2370 if (!compat20) 2371 fatal("session_set_fds: called for proto != 2.0"); 2372 /* 2373 * now that have a child and a pipe to the child, 2374 * we can activate our channel and register the fd's 2375 */ 2376 if (s->chanid == -1) 2377 fatal("no channel for session %d", s->self); 2378 if (options.hpn_disabled) 2379 channel_set_fds(s->chanid, fdout, fdin, fderr, 2380 ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ, 2381 1, is_tty, CHAN_SES_WINDOW_DEFAULT); 2382 else 2383 channel_set_fds(s->chanid, fdout, fdin, fderr, 2384 ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ, 2385 1, is_tty, options.hpn_buffer_size); 2386} 2387 2388/* 2389 * Function to perform pty cleanup. Also called if we get aborted abnormally 2390 * (e.g., due to a dropped connection). 2391 */ 2392void 2393session_pty_cleanup2(Session *s) 2394{ 2395 if (s == NULL) { 2396 error("session_pty_cleanup: no session"); 2397 return; 2398 } 2399 if (s->ttyfd == -1) 2400 return; 2401 2402 debug("session_pty_cleanup: session %d release %s", s->self, s->tty); 2403 2404 /* Record that the user has logged out. */ 2405 if (s->pid != 0) 2406 record_logout(s->pid, s->tty, s->pw->pw_name); 2407 2408 /* Release the pseudo-tty. */ 2409 if (getuid() == 0) 2410 pty_release(s->tty); 2411 2412 /* 2413 * Close the server side of the socket pairs. We must do this after 2414 * the pty cleanup, so that another process doesn't get this pty 2415 * while we're still cleaning up. 2416 */ 2417 if (s->ptymaster != -1 && close(s->ptymaster) < 0) 2418 error("close(s->ptymaster/%d): %s", 2419 s->ptymaster, strerror(errno)); 2420 2421 /* unlink pty from session */ 2422 s->ttyfd = -1; 2423} 2424 2425void 2426session_pty_cleanup(Session *s) 2427{ 2428 PRIVSEP(session_pty_cleanup2(s)); 2429} 2430 2431static char * 2432sig2name(int sig) 2433{ 2434#define SSH_SIG(x) if (sig == SIG ## x) return #x 2435 SSH_SIG(ABRT); 2436 SSH_SIG(ALRM); 2437 SSH_SIG(FPE); 2438 SSH_SIG(HUP); 2439 SSH_SIG(ILL); 2440 SSH_SIG(INT); 2441 SSH_SIG(KILL); 2442 SSH_SIG(PIPE); 2443 SSH_SIG(QUIT); 2444 SSH_SIG(SEGV); 2445 SSH_SIG(TERM); 2446 SSH_SIG(USR1); 2447 SSH_SIG(USR2); 2448#undef SSH_SIG 2449 return "SIG@openssh.com"; 2450} 2451 2452static void 2453session_close_x11(int id) 2454{ 2455 Channel *c; 2456 2457 if ((c = channel_by_id(id)) == NULL) { 2458 debug("session_close_x11: x11 channel %d missing", id); 2459 } else { 2460 /* Detach X11 listener */ 2461 debug("session_close_x11: detach x11 channel %d", id); 2462 channel_cancel_cleanup(id); 2463 if (c->ostate != CHAN_OUTPUT_CLOSED) 2464 chan_mark_dead(c); 2465 } 2466} 2467 2468static void 2469session_close_single_x11(int id, void *arg) 2470{ 2471 Session *s; 2472 u_int i; 2473 2474 debug3("session_close_single_x11: channel %d", id); 2475 channel_cancel_cleanup(id); 2476 if ((s = session_by_x11_channel(id)) == NULL) 2477 fatal("session_close_single_x11: no x11 channel %d", id); 2478 for (i = 0; s->x11_chanids[i] != -1; i++) { 2479 debug("session_close_single_x11: session %d: " 2480 "closing channel %d", s->self, s->x11_chanids[i]); 2481 /* 2482 * The channel "id" is already closing, but make sure we 2483 * close all of its siblings. 2484 */ 2485 if (s->x11_chanids[i] != id) 2486 session_close_x11(s->x11_chanids[i]); 2487 } 2488 free(s->x11_chanids); 2489 s->x11_chanids = NULL; 2490 free(s->display); 2491 s->display = NULL; 2492 free(s->auth_proto); 2493 s->auth_proto = NULL; 2494 free(s->auth_data); 2495 s->auth_data = NULL; 2496 free(s->auth_display); 2497 s->auth_display = NULL; 2498} 2499 2500static void 2501session_exit_message(Session *s, int status) 2502{ 2503 Channel *c; 2504 2505 if ((c = channel_lookup(s->chanid)) == NULL) 2506 fatal("session_exit_message: session %d: no channel %d", 2507 s->self, s->chanid); 2508 debug("session_exit_message: session %d channel %d pid %ld", 2509 s->self, s->chanid, (long)s->pid); 2510 2511 if (WIFEXITED(status)) { 2512 channel_request_start(s->chanid, "exit-status", 0); 2513 packet_put_int(WEXITSTATUS(status)); 2514 packet_send(); 2515 } else if (WIFSIGNALED(status)) { 2516 channel_request_start(s->chanid, "exit-signal", 0); 2517 packet_put_cstring(sig2name(WTERMSIG(status))); 2518#ifdef WCOREDUMP 2519 packet_put_char(WCOREDUMP(status)? 1 : 0); 2520#else /* WCOREDUMP */ 2521 packet_put_char(0); 2522#endif /* WCOREDUMP */ 2523 packet_put_cstring(""); 2524 packet_put_cstring(""); 2525 packet_send(); 2526 } else { 2527 /* Some weird exit cause. Just exit. */ 2528 packet_disconnect("wait returned status %04x.", status); 2529 } 2530 2531 /* disconnect channel */ 2532 debug("session_exit_message: release channel %d", s->chanid); 2533 2534 /* 2535 * Adjust cleanup callback attachment to send close messages when 2536 * the channel gets EOF. The session will be then be closed 2537 * by session_close_by_channel when the childs close their fds. 2538 */ 2539 channel_register_cleanup(c->self, session_close_by_channel, 1); 2540 2541 /* 2542 * emulate a write failure with 'chan_write_failed', nobody will be 2543 * interested in data we write. 2544 * Note that we must not call 'chan_read_failed', since there could 2545 * be some more data waiting in the pipe. 2546 */ 2547 if (c->ostate != CHAN_OUTPUT_CLOSED) 2548 chan_write_failed(c); 2549} 2550 2551void 2552session_close(Session *s) 2553{ 2554 u_int i; 2555 2556 debug("session_close: session %d pid %ld", s->self, (long)s->pid); 2557 if (s->ttyfd != -1) 2558 session_pty_cleanup(s); 2559 free(s->term); 2560 free(s->display); 2561 free(s->x11_chanids); 2562 free(s->auth_display); 2563 free(s->auth_data); 2564 free(s->auth_proto); 2565 free(s->subsys); 2566 if (s->env != NULL) { 2567 for (i = 0; i < s->num_env; i++) { 2568 free(s->env[i].name); 2569 free(s->env[i].val); 2570 } 2571 free(s->env); 2572 } 2573 session_proctitle(s); 2574 session_unused(s->self); 2575} 2576 2577void 2578session_close_by_pid(pid_t pid, int status) 2579{ 2580 Session *s = session_by_pid(pid); 2581 if (s == NULL) { 2582 debug("session_close_by_pid: no session for pid %ld", 2583 (long)pid); 2584 return; 2585 } 2586 if (s->chanid != -1) 2587 session_exit_message(s, status); 2588 if (s->ttyfd != -1) 2589 session_pty_cleanup(s); 2590 s->pid = 0; 2591} 2592 2593/* 2594 * this is called when a channel dies before 2595 * the session 'child' itself dies 2596 */ 2597void 2598session_close_by_channel(int id, void *arg) 2599{ 2600 Session *s = session_by_channel(id); 2601 u_int i; 2602 2603 if (s == NULL) { 2604 debug("session_close_by_channel: no session for id %d", id); 2605 return; 2606 } 2607 debug("session_close_by_channel: channel %d child %ld", 2608 id, (long)s->pid); 2609 if (s->pid != 0) { 2610 debug("session_close_by_channel: channel %d: has child", id); 2611 /* 2612 * delay detach of session, but release pty, since 2613 * the fd's to the child are already closed 2614 */ 2615 if (s->ttyfd != -1) 2616 session_pty_cleanup(s); 2617 return; 2618 } 2619 /* detach by removing callback */ 2620 channel_cancel_cleanup(s->chanid); 2621 2622 /* Close any X11 listeners associated with this session */ 2623 if (s->x11_chanids != NULL) { 2624 for (i = 0; s->x11_chanids[i] != -1; i++) { 2625 session_close_x11(s->x11_chanids[i]); 2626 s->x11_chanids[i] = -1; 2627 } 2628 } 2629 2630 s->chanid = -1; 2631 session_close(s); 2632} 2633 2634void 2635session_destroy_all(void (*closefunc)(Session *)) 2636{ 2637 int i; 2638 for (i = 0; i < sessions_nalloc; i++) { 2639 Session *s = &sessions[i]; 2640 if (s->used) { 2641 if (closefunc != NULL) 2642 closefunc(s); 2643 else 2644 session_close(s); 2645 } 2646 } 2647} 2648 2649static char * 2650session_tty_list(void) 2651{ 2652 static char buf[1024]; 2653 int i; 2654 char *cp; 2655 2656 buf[0] = '\0'; 2657 for (i = 0; i < sessions_nalloc; i++) { 2658 Session *s = &sessions[i]; 2659 if (s->used && s->ttyfd != -1) { 2660 2661 if (strncmp(s->tty, "/dev/", 5) != 0) { 2662 cp = strrchr(s->tty, '/'); 2663 cp = (cp == NULL) ? s->tty : cp + 1; 2664 } else 2665 cp = s->tty + 5; 2666 2667 if (buf[0] != '\0') 2668 strlcat(buf, ",", sizeof buf); 2669 strlcat(buf, cp, sizeof buf); 2670 } 2671 } 2672 if (buf[0] == '\0') 2673 strlcpy(buf, "notty", sizeof buf); 2674 return buf; 2675} 2676 2677void 2678session_proctitle(Session *s) 2679{ 2680 if (s->pw == NULL) 2681 error("no user for session %d", s->self); 2682 else 2683 setproctitle("%s@%s", s->pw->pw_name, session_tty_list()); 2684} 2685 2686int 2687session_setup_x11fwd(Session *s) 2688{ 2689 struct stat st; 2690 char display[512], auth_display[512]; 2691 char hostname[MAXHOSTNAMELEN]; 2692 u_int i; 2693 2694 if (no_x11_forwarding_flag) { 2695 packet_send_debug("X11 forwarding disabled in user configuration file."); 2696 return 0; 2697 } 2698 if (!options.x11_forwarding) { 2699 debug("X11 forwarding disabled in server configuration file."); 2700 return 0; 2701 } 2702 if (!options.xauth_location || 2703 (stat(options.xauth_location, &st) == -1)) { 2704 packet_send_debug("No xauth program; cannot forward with spoofing."); 2705 return 0; 2706 } 2707 if (options.use_login) { 2708 packet_send_debug("X11 forwarding disabled; " 2709 "not compatible with UseLogin=yes."); 2710 return 0; 2711 } 2712 if (s->display != NULL) { 2713 debug("X11 display already set."); 2714 return 0; 2715 } 2716 if (x11_create_display_inet(options.x11_display_offset, 2717 options.x11_use_localhost, s->single_connection, 2718 &s->display_number, &s->x11_chanids) == -1) { 2719 debug("x11_create_display_inet failed."); 2720 return 0; 2721 } 2722 for (i = 0; s->x11_chanids[i] != -1; i++) { 2723 channel_register_cleanup(s->x11_chanids[i], 2724 session_close_single_x11, 0); 2725 } 2726 2727 /* Set up a suitable value for the DISPLAY variable. */ 2728 if (gethostname(hostname, sizeof(hostname)) < 0) 2729 fatal("gethostname: %.100s", strerror(errno)); 2730 /* 2731 * auth_display must be used as the displayname when the 2732 * authorization entry is added with xauth(1). This will be 2733 * different than the DISPLAY string for localhost displays. 2734 */ 2735 if (options.x11_use_localhost) { 2736 snprintf(display, sizeof display, "localhost:%u.%u", 2737 s->display_number, s->screen); 2738 snprintf(auth_display, sizeof auth_display, "unix:%u.%u", 2739 s->display_number, s->screen); 2740 s->display = xstrdup(display); 2741 s->auth_display = xstrdup(auth_display); 2742 } else { 2743#ifdef IPADDR_IN_DISPLAY 2744 struct hostent *he; 2745 struct in_addr my_addr; 2746 2747 he = gethostbyname(hostname); 2748 if (he == NULL) { 2749 error("Can't get IP address for X11 DISPLAY."); 2750 packet_send_debug("Can't get IP address for X11 DISPLAY."); 2751 return 0; 2752 } 2753 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr)); 2754 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr), 2755 s->display_number, s->screen); 2756#else 2757 snprintf(display, sizeof display, "%.400s:%u.%u", hostname, 2758 s->display_number, s->screen); 2759#endif 2760 s->display = xstrdup(display); 2761 s->auth_display = xstrdup(display); 2762 } 2763 2764 return 1; 2765} 2766 2767static void 2768do_authenticated2(Authctxt *authctxt) 2769{ 2770 server_loop2(authctxt); 2771} 2772 2773void 2774do_cleanup(Authctxt *authctxt) 2775{ 2776 static int called = 0; 2777 2778 debug("do_cleanup"); 2779 2780 /* no cleanup if we're in the child for login shell */ 2781 if (is_child) 2782 return; 2783 2784 /* avoid double cleanup */ 2785 if (called) 2786 return; 2787 called = 1; 2788 2789 if (authctxt == NULL) 2790 return; 2791 2792#ifdef USE_PAM 2793 if (options.use_pam) { 2794 sshpam_cleanup(); 2795 sshpam_thread_cleanup(); 2796 } 2797#endif 2798 2799 if (!authctxt->authenticated) 2800 return; 2801 2802#ifdef KRB5 2803 if (options.kerberos_ticket_cleanup && 2804 authctxt->krb5_ctx) 2805 krb5_cleanup_proc(authctxt); 2806#endif 2807 2808#ifdef GSSAPI 2809 if (compat20 && options.gss_cleanup_creds) 2810 ssh_gssapi_cleanup_creds(); 2811#endif 2812 2813 /* remove agent socket */ 2814 auth_sock_cleanup_proc(authctxt->pw); 2815 2816 /* 2817 * Cleanup ptys/utmp only if privsep is disabled, 2818 * or if running in monitor. 2819 */ 2820 if (!use_privsep || mm_is_monitor()) 2821 session_destroy_all(session_pty_cleanup2); 2822} 2823