1/* $OpenBSD: session.c,v 1.258 2010/11/25 04:10:09 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 <errno.h> 50#include <fcntl.h> 51#include <grp.h> 52#ifdef HAVE_PATHS_H 53#include <paths.h> 54#endif 55#include <pwd.h> 56#include <signal.h> 57#include <stdarg.h> 58#include <stdio.h> 59#include <stdlib.h> 60#include <string.h> 61#include <unistd.h> 62 63#include "openbsd-compat/sys-queue.h" 64#include "xmalloc.h" 65#include "ssh.h" 66#include "ssh1.h" 67#include "ssh2.h" 68#include "sshpty.h" 69#include "packet.h" 70#include "buffer.h" 71#include "match.h" 72#include "uidswap.h" 73#include "compat.h" 74#include "channels.h" 75#include "key.h" 76#include "cipher.h" 77#ifdef GSSAPI 78#include "ssh-gss.h" 79#endif 80#include "hostfile.h" 81#include "auth.h" 82#include "auth-options.h" 83#include "pathnames.h" 84#include "log.h" 85#include "servconf.h" 86#include "sshlogin.h" 87#include "serverloop.h" 88#include "canohost.h" 89#include "misc.h" 90#include "session.h" 91#include "kex.h" 92#include "monitor_wrap.h" 93#include "sftp.h" 94 95#if defined(KRB5) && defined(USE_AFS) 96#include <kafs.h> 97#endif 98 99#ifdef WITH_SELINUX 100#include <selinux/selinux.h> 101#endif 102 103#define IS_INTERNAL_SFTP(c) \ 104 (!strncmp(c, INTERNAL_SFTP_NAME, sizeof(INTERNAL_SFTP_NAME) - 1) && \ 105 (c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\0' || \ 106 c[sizeof(INTERNAL_SFTP_NAME) - 1] == ' ' || \ 107 c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\t')) 108 109/* func */ 110 111Session *session_new(void); 112void session_set_fds(Session *, int, int, int, int, int); 113void session_pty_cleanup(Session *); 114void session_proctitle(Session *); 115int session_setup_x11fwd(Session *); 116int do_exec_pty(Session *, const char *); 117int do_exec_no_pty(Session *, const char *); 118int do_exec(Session *, const char *); 119void do_login(Session *, const char *); 120#ifdef LOGIN_NEEDS_UTMPX 121static void do_pre_login(Session *s); 122#endif 123void do_child(Session *, const char *); 124void do_motd(void); 125int check_quietlogin(Session *, const char *); 126 127static void do_authenticated1(Authctxt *); 128static void do_authenticated2(Authctxt *); 129 130static int session_pty_req(Session *); 131 132/* import */ 133extern ServerOptions options; 134extern char *__progname; 135extern int log_stderr; 136extern int debug_flag; 137extern u_int utmp_len; 138extern int startup_pipe; 139extern void destroy_sensitive_data(void); 140extern Buffer loginmsg; 141 142/* original command from peer. */ 143const char *original_command = NULL; 144 145/* data */ 146static int sessions_first_unused = -1; 147static int sessions_nalloc = 0; 148static Session *sessions = NULL; 149 150#define SUBSYSTEM_NONE 0 151#define SUBSYSTEM_EXT 1 152#define SUBSYSTEM_INT_SFTP 2 153#define SUBSYSTEM_INT_SFTP_ERROR 3 154 155#ifdef HAVE_LOGIN_CAP 156login_cap_t *lc; 157#endif 158 159static int is_child = 0; 160 161/* Name and directory of socket for authentication agent forwarding. */ 162static char *auth_sock_name = NULL; 163static char *auth_sock_dir = NULL; 164 165/* removes the agent forwarding socket */ 166 167static void 168auth_sock_cleanup_proc(struct passwd *pw) 169{ 170 if (auth_sock_name != NULL) { 171 temporarily_use_uid(pw); 172 unlink(auth_sock_name); 173 rmdir(auth_sock_dir); 174 auth_sock_name = NULL; 175 restore_uid(); 176 } 177} 178 179static int 180auth_input_request_forwarding(struct passwd * pw) 181{ 182 Channel *nc; 183 int sock = -1; 184 struct sockaddr_un sunaddr; 185 186 if (auth_sock_name != NULL) { 187 error("authentication forwarding requested twice."); 188 return 0; 189 } 190 191 /* Temporarily drop privileged uid for mkdir/bind. */ 192 temporarily_use_uid(pw); 193 194 /* Allocate a buffer for the socket name, and format the name. */ 195 auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX"); 196 197 /* Create private directory for socket */ 198 if (mkdtemp(auth_sock_dir) == NULL) { 199 packet_send_debug("Agent forwarding disabled: " 200 "mkdtemp() failed: %.100s", strerror(errno)); 201 restore_uid(); 202 xfree(auth_sock_dir); 203 auth_sock_dir = NULL; 204 goto authsock_err; 205 } 206 207 xasprintf(&auth_sock_name, "%s/agent.%ld", 208 auth_sock_dir, (long) getpid()); 209 210 /* Create the socket. */ 211 sock = socket(AF_UNIX, SOCK_STREAM, 0); 212 if (sock < 0) { 213 error("socket: %.100s", strerror(errno)); 214 restore_uid(); 215 goto authsock_err; 216 } 217 218 /* Bind it to the name. */ 219 memset(&sunaddr, 0, sizeof(sunaddr)); 220 sunaddr.sun_family = AF_UNIX; 221 strlcpy(sunaddr.sun_path, auth_sock_name, sizeof(sunaddr.sun_path)); 222 223 if (bind(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) < 0) { 224 error("bind: %.100s", strerror(errno)); 225 restore_uid(); 226 goto authsock_err; 227 } 228 229 /* Restore the privileged uid. */ 230 restore_uid(); 231 232 /* Start listening on the socket. */ 233 if (listen(sock, SSH_LISTEN_BACKLOG) < 0) { 234 error("listen: %.100s", strerror(errno)); 235 goto authsock_err; 236 } 237 238 /* Allocate a channel for the authentication agent socket. */ 239 nc = channel_new("auth socket", 240 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1, 241 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 242 0, "auth socket", 1); 243 nc->path = xstrdup(auth_sock_name); 244 return 1; 245 246 authsock_err: 247 if (auth_sock_name != NULL) 248 xfree(auth_sock_name); 249 if (auth_sock_dir != NULL) { 250 rmdir(auth_sock_dir); 251 xfree(auth_sock_dir); 252 } 253 if (sock != -1) 254 close(sock); 255 auth_sock_name = NULL; 256 auth_sock_dir = NULL; 257 return 0; 258} 259 260static void 261display_loginmsg(void) 262{ 263 if (buffer_len(&loginmsg) > 0) { 264 buffer_append(&loginmsg, "\0", 1); 265 printf("%s", (char *)buffer_ptr(&loginmsg)); 266 buffer_clear(&loginmsg); 267 } 268} 269 270void 271do_authenticated(Authctxt *authctxt) 272{ 273 setproctitle("%s", authctxt->pw->pw_name); 274 275 /* setup the channel layer */ 276 if (!no_port_forwarding_flag && options.allow_tcp_forwarding) 277 channel_permit_all_opens(); 278 279 auth_debug_send(); 280 281 if (compat20) 282 do_authenticated2(authctxt); 283 else 284 do_authenticated1(authctxt); 285 286 do_cleanup(authctxt); 287} 288 289/* 290 * Prepares for an interactive session. This is called after the user has 291 * been successfully authenticated. During this message exchange, pseudo 292 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings 293 * are requested, etc. 294 */ 295static void 296do_authenticated1(Authctxt *authctxt) 297{ 298 Session *s; 299 char *command; 300 int success, type, screen_flag; 301 int enable_compression_after_reply = 0; 302 u_int proto_len, data_len, dlen, compression_level = 0; 303 304 s = session_new(); 305 if (s == NULL) { 306 error("no more sessions"); 307 return; 308 } 309 s->authctxt = authctxt; 310 s->pw = authctxt->pw; 311 312 /* 313 * We stay in this loop until the client requests to execute a shell 314 * or a command. 315 */ 316 for (;;) { 317 success = 0; 318 319 /* Get a packet from the client. */ 320 type = packet_read(); 321 322 /* Process the packet. */ 323 switch (type) { 324 case SSH_CMSG_REQUEST_COMPRESSION: 325 compression_level = packet_get_int(); 326 packet_check_eom(); 327 if (compression_level < 1 || compression_level > 9) { 328 packet_send_debug("Received invalid compression level %d.", 329 compression_level); 330 break; 331 } 332 if (options.compression == COMP_NONE) { 333 debug2("compression disabled"); 334 break; 335 } 336 /* Enable compression after we have responded with SUCCESS. */ 337 enable_compression_after_reply = 1; 338 success = 1; 339 break; 340 341 case SSH_CMSG_REQUEST_PTY: 342 success = session_pty_req(s); 343 break; 344 345 case SSH_CMSG_X11_REQUEST_FORWARDING: 346 s->auth_proto = packet_get_string(&proto_len); 347 s->auth_data = packet_get_string(&data_len); 348 349 screen_flag = packet_get_protocol_flags() & 350 SSH_PROTOFLAG_SCREEN_NUMBER; 351 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag); 352 353 if (packet_remaining() == 4) { 354 if (!screen_flag) 355 debug2("Buggy client: " 356 "X11 screen flag missing"); 357 s->screen = packet_get_int(); 358 } else { 359 s->screen = 0; 360 } 361 packet_check_eom(); 362 success = session_setup_x11fwd(s); 363 if (!success) { 364 xfree(s->auth_proto); 365 xfree(s->auth_data); 366 s->auth_proto = NULL; 367 s->auth_data = NULL; 368 } 369 break; 370 371 case SSH_CMSG_AGENT_REQUEST_FORWARDING: 372 if (!options.allow_agent_forwarding || 373 no_agent_forwarding_flag || compat13) { 374 debug("Authentication agent forwarding not permitted for this authentication."); 375 break; 376 } 377 debug("Received authentication agent forwarding request."); 378 success = auth_input_request_forwarding(s->pw); 379 break; 380 381 case SSH_CMSG_PORT_FORWARD_REQUEST: 382 if (no_port_forwarding_flag) { 383 debug("Port forwarding not permitted for this authentication."); 384 break; 385 } 386 if (!options.allow_tcp_forwarding) { 387 debug("Port forwarding not permitted."); 388 break; 389 } 390 debug("Received TCP/IP port forwarding request."); 391 if (channel_input_port_forward_request(s->pw->pw_uid == 0, 392 options.gateway_ports) < 0) { 393 debug("Port forwarding failed."); 394 break; 395 } 396 success = 1; 397 break; 398 399 case SSH_CMSG_MAX_PACKET_SIZE: 400 if (packet_set_maxsize(packet_get_int()) > 0) 401 success = 1; 402 break; 403 404 case SSH_CMSG_EXEC_SHELL: 405 case SSH_CMSG_EXEC_CMD: 406 if (type == SSH_CMSG_EXEC_CMD) { 407 command = packet_get_string(&dlen); 408 debug("Exec command '%.500s'", command); 409 if (do_exec(s, command) != 0) 410 packet_disconnect( 411 "command execution failed"); 412 xfree(command); 413 } else { 414 if (do_exec(s, NULL) != 0) 415 packet_disconnect( 416 "shell execution failed"); 417 } 418 packet_check_eom(); 419 session_close(s); 420 return; 421 422 default: 423 /* 424 * Any unknown messages in this phase are ignored, 425 * and a failure message is returned. 426 */ 427 logit("Unknown packet type received after authentication: %d", type); 428 } 429 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE); 430 packet_send(); 431 packet_write_wait(); 432 433 /* Enable compression now that we have replied if appropriate. */ 434 if (enable_compression_after_reply) { 435 enable_compression_after_reply = 0; 436 packet_start_compression(compression_level); 437 } 438 } 439} 440 441#define USE_PIPES 442/* 443 * This is called to fork and execute a command when we have no tty. This 444 * will call do_child from the child, and server_loop from the parent after 445 * setting up file descriptors and such. 446 */ 447int 448do_exec_no_pty(Session *s, const char *command) 449{ 450 pid_t pid; 451 452#ifdef USE_PIPES 453 int pin[2], pout[2], perr[2]; 454 455 if (s == NULL) 456 fatal("do_exec_no_pty: no session"); 457 458 /* Allocate pipes for communicating with the program. */ 459 if (pipe(pin) < 0) { 460 error("%s: pipe in: %.100s", __func__, strerror(errno)); 461 return -1; 462 } 463 if (pipe(pout) < 0) { 464 error("%s: pipe out: %.100s", __func__, strerror(errno)); 465 close(pin[0]); 466 close(pin[1]); 467 return -1; 468 } 469 if (pipe(perr) < 0) { 470 error("%s: pipe err: %.100s", __func__, 471 strerror(errno)); 472 close(pin[0]); 473 close(pin[1]); 474 close(pout[0]); 475 close(pout[1]); 476 return -1; 477 } 478#else 479 int inout[2], err[2]; 480 481 if (s == NULL) 482 fatal("do_exec_no_pty: no session"); 483 484 /* Uses socket pairs to communicate with the program. */ 485 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) { 486 error("%s: socketpair #1: %.100s", __func__, strerror(errno)); 487 return -1; 488 } 489 if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) { 490 error("%s: socketpair #2: %.100s", __func__, 491 strerror(errno)); 492 close(inout[0]); 493 close(inout[1]); 494 return -1; 495 } 496#endif 497 498 session_proctitle(s); 499 500 /* Fork the child. */ 501 switch ((pid = fork())) { 502 case -1: 503 error("%s: fork: %.100s", __func__, strerror(errno)); 504#ifdef USE_PIPES 505 close(pin[0]); 506 close(pin[1]); 507 close(pout[0]); 508 close(pout[1]); 509 close(perr[0]); 510 close(perr[1]); 511#else 512 close(inout[0]); 513 close(inout[1]); 514 close(err[0]); 515 close(err[1]); 516#endif 517 return -1; 518 case 0: 519 is_child = 1; 520 521 /* Child. Reinitialize the log since the pid has changed. */ 522 log_init(__progname, options.log_level, 523 options.log_facility, log_stderr); 524 525 /* 526 * Create a new session and process group since the 4.4BSD 527 * setlogin() affects the entire process group. 528 */ 529 if (setsid() < 0) 530 error("setsid failed: %.100s", strerror(errno)); 531 532#ifdef USE_PIPES 533 /* 534 * Redirect stdin. We close the parent side of the socket 535 * pair, and make the child side the standard input. 536 */ 537 close(pin[1]); 538 if (dup2(pin[0], 0) < 0) 539 perror("dup2 stdin"); 540 close(pin[0]); 541 542 /* Redirect stdout. */ 543 close(pout[0]); 544 if (dup2(pout[1], 1) < 0) 545 perror("dup2 stdout"); 546 close(pout[1]); 547 548 /* Redirect stderr. */ 549 close(perr[0]); 550 if (dup2(perr[1], 2) < 0) 551 perror("dup2 stderr"); 552 close(perr[1]); 553#else 554 /* 555 * Redirect stdin, stdout, and stderr. Stdin and stdout will 556 * use the same socket, as some programs (particularly rdist) 557 * seem to depend on it. 558 */ 559 close(inout[1]); 560 close(err[1]); 561 if (dup2(inout[0], 0) < 0) /* stdin */ 562 perror("dup2 stdin"); 563 if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */ 564 perror("dup2 stdout"); 565 close(inout[0]); 566 if (dup2(err[0], 2) < 0) /* stderr */ 567 perror("dup2 stderr"); 568 close(err[0]); 569#endif 570 571 572#ifdef _UNICOS 573 cray_init_job(s->pw); /* set up cray jid and tmpdir */ 574#endif 575 576 /* Do processing for the child (exec command etc). */ 577 do_child(s, command); 578 /* NOTREACHED */ 579 default: 580 break; 581 } 582 583#ifdef _UNICOS 584 signal(WJSIGNAL, cray_job_termination_handler); 585#endif /* _UNICOS */ 586#ifdef HAVE_CYGWIN 587 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE); 588#endif 589 590 s->pid = pid; 591 /* Set interactive/non-interactive mode. */ 592 packet_set_interactive(s->display != NULL, 593 options.ip_qos_interactive, options.ip_qos_bulk); 594 595 /* 596 * Clear loginmsg, since it's the child's responsibility to display 597 * it to the user, otherwise multiple sessions may accumulate 598 * multiple copies of the login messages. 599 */ 600 buffer_clear(&loginmsg); 601 602#ifdef USE_PIPES 603 /* We are the parent. Close the child sides of the pipes. */ 604 close(pin[0]); 605 close(pout[1]); 606 close(perr[1]); 607 608 if (compat20) { 609 session_set_fds(s, pin[1], pout[0], perr[0], 610 s->is_subsystem, 0); 611 } else { 612 /* Enter the interactive session. */ 613 server_loop(pid, pin[1], pout[0], perr[0]); 614 /* server_loop has closed pin[1], pout[0], and perr[0]. */ 615 } 616#else 617 /* We are the parent. Close the child sides of the socket pairs. */ 618 close(inout[0]); 619 close(err[0]); 620 621 /* 622 * Enter the interactive session. Note: server_loop must be able to 623 * handle the case that fdin and fdout are the same. 624 */ 625 if (compat20) { 626 session_set_fds(s, inout[1], inout[1], err[1], 627 s->is_subsystem, 0); 628 } else { 629 server_loop(pid, inout[1], inout[1], err[1]); 630 /* server_loop has closed inout[1] and err[1]. */ 631 } 632#endif 633 return 0; 634} 635 636/* 637 * This is called to fork and execute a command when we have a tty. This 638 * will call do_child from the child, and server_loop from the parent after 639 * setting up file descriptors, controlling tty, updating wtmp, utmp, 640 * lastlog, and other such operations. 641 */ 642int 643do_exec_pty(Session *s, const char *command) 644{ 645 int fdout, ptyfd, ttyfd, ptymaster; 646 pid_t pid; 647 648 if (s == NULL) 649 fatal("do_exec_pty: no session"); 650 ptyfd = s->ptyfd; 651 ttyfd = s->ttyfd; 652 653 /* 654 * Create another descriptor of the pty master side for use as the 655 * standard input. We could use the original descriptor, but this 656 * simplifies code in server_loop. The descriptor is bidirectional. 657 * Do this before forking (and cleanup in the child) so as to 658 * detect and gracefully fail out-of-fd conditions. 659 */ 660 if ((fdout = dup(ptyfd)) < 0) { 661 error("%s: dup #1: %s", __func__, strerror(errno)); 662 close(ttyfd); 663 close(ptyfd); 664 return -1; 665 } 666 /* we keep a reference to the pty master */ 667 if ((ptymaster = dup(ptyfd)) < 0) { 668 error("%s: dup #2: %s", __func__, strerror(errno)); 669 close(ttyfd); 670 close(ptyfd); 671 close(fdout); 672 return -1; 673 } 674 675 /* Fork the child. */ 676 switch ((pid = fork())) { 677 case -1: 678 error("%s: fork: %.100s", __func__, strerror(errno)); 679 close(fdout); 680 close(ptymaster); 681 close(ttyfd); 682 close(ptyfd); 683 return -1; 684 case 0: 685 is_child = 1; 686 687 close(fdout); 688 close(ptymaster); 689 690 /* Child. Reinitialize the log because the pid has changed. */ 691 log_init(__progname, options.log_level, 692 options.log_facility, log_stderr); 693 /* Close the master side of the pseudo tty. */ 694 close(ptyfd); 695 696 /* Make the pseudo tty our controlling tty. */ 697 pty_make_controlling_tty(&ttyfd, s->tty); 698 699 /* Redirect stdin/stdout/stderr from the pseudo tty. */ 700 if (dup2(ttyfd, 0) < 0) 701 error("dup2 stdin: %s", strerror(errno)); 702 if (dup2(ttyfd, 1) < 0) 703 error("dup2 stdout: %s", strerror(errno)); 704 if (dup2(ttyfd, 2) < 0) 705 error("dup2 stderr: %s", strerror(errno)); 706 707 /* Close the extra descriptor for the pseudo tty. */ 708 close(ttyfd); 709 710 /* record login, etc. similar to login(1) */ 711#ifndef HAVE_OSF_SIA 712 if (!(options.use_login && command == NULL)) { 713#ifdef _UNICOS 714 cray_init_job(s->pw); /* set up cray jid and tmpdir */ 715#endif /* _UNICOS */ 716 do_login(s, command); 717 } 718# ifdef LOGIN_NEEDS_UTMPX 719 else 720 do_pre_login(s); 721# endif 722#endif 723 /* 724 * Do common processing for the child, such as execing 725 * the command. 726 */ 727 do_child(s, command); 728 /* NOTREACHED */ 729 default: 730 break; 731 } 732 733#ifdef _UNICOS 734 signal(WJSIGNAL, cray_job_termination_handler); 735#endif /* _UNICOS */ 736#ifdef HAVE_CYGWIN 737 cygwin_set_impersonation_token(INVALID_HANDLE_VALUE); 738#endif 739 740 s->pid = pid; 741 742 /* Parent. Close the slave side of the pseudo tty. */ 743 close(ttyfd); 744 745 /* Enter interactive session. */ 746 s->ptymaster = ptymaster; 747 packet_set_interactive(1, 748 options.ip_qos_interactive, options.ip_qos_bulk); 749 if (compat20) { 750 session_set_fds(s, ptyfd, fdout, -1, 1, 1); 751 } else { 752 server_loop(pid, ptyfd, fdout, -1); 753 /* server_loop _has_ closed ptyfd and fdout. */ 754 } 755 return 0; 756} 757 758#ifdef LOGIN_NEEDS_UTMPX 759static void 760do_pre_login(Session *s) 761{ 762 socklen_t fromlen; 763 struct sockaddr_storage from; 764 pid_t pid = getpid(); 765 766 /* 767 * Get IP address of client. If the connection is not a socket, let 768 * the address be 0.0.0.0. 769 */ 770 memset(&from, 0, sizeof(from)); 771 fromlen = sizeof(from); 772 if (packet_connection_is_on_socket()) { 773 if (getpeername(packet_get_connection_in(), 774 (struct sockaddr *)&from, &fromlen) < 0) { 775 debug("getpeername: %.100s", strerror(errno)); 776 cleanup_exit(255); 777 } 778 } 779 780 record_utmp_only(pid, s->tty, s->pw->pw_name, 781 get_remote_name_or_ip(utmp_len, options.use_dns), 782 (struct sockaddr *)&from, fromlen); 783} 784#endif 785 786/* 787 * This is called to fork and execute a command. If another command is 788 * to be forced, execute that instead. 789 */ 790int 791do_exec(Session *s, const char *command) 792{ 793 int ret; 794 795 if (options.adm_forced_command) { 796 original_command = command; 797 command = options.adm_forced_command; 798 if (IS_INTERNAL_SFTP(command)) { 799 s->is_subsystem = s->is_subsystem ? 800 SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR; 801 } else if (s->is_subsystem) 802 s->is_subsystem = SUBSYSTEM_EXT; 803 debug("Forced command (config) '%.900s'", command); 804 } else if (forced_command) { 805 original_command = command; 806 command = forced_command; 807 if (IS_INTERNAL_SFTP(command)) { 808 s->is_subsystem = s->is_subsystem ? 809 SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR; 810 } else if (s->is_subsystem) 811 s->is_subsystem = SUBSYSTEM_EXT; 812 debug("Forced command (key option) '%.900s'", command); 813 } 814 815#ifdef SSH_AUDIT_EVENTS 816 if (command != NULL) 817 PRIVSEP(audit_run_command(command)); 818 else if (s->ttyfd == -1) { 819 char *shell = s->pw->pw_shell; 820 821 if (shell[0] == '\0') /* empty shell means /bin/sh */ 822 shell =_PATH_BSHELL; 823 PRIVSEP(audit_run_command(shell)); 824 } 825#endif 826 if (s->ttyfd != -1) 827 ret = do_exec_pty(s, command); 828 else 829 ret = do_exec_no_pty(s, command); 830 831 original_command = NULL; 832 833 /* 834 * Clear loginmsg: it's the child's responsibility to display 835 * it to the user, otherwise multiple sessions may accumulate 836 * multiple copies of the login messages. 837 */ 838 buffer_clear(&loginmsg); 839 840 return ret; 841} 842 843/* administrative, login(1)-like work */ 844void 845do_login(Session *s, const char *command) 846{ 847 socklen_t fromlen; 848 struct sockaddr_storage from; 849 struct passwd * pw = s->pw; 850 pid_t pid = getpid(); 851 852 /* 853 * Get IP address of client. If the connection is not a socket, let 854 * the address be 0.0.0.0. 855 */ 856 memset(&from, 0, sizeof(from)); 857 fromlen = sizeof(from); 858 if (packet_connection_is_on_socket()) { 859 if (getpeername(packet_get_connection_in(), 860 (struct sockaddr *)&from, &fromlen) < 0) { 861 debug("getpeername: %.100s", strerror(errno)); 862 cleanup_exit(255); 863 } 864 } 865 866 /* Record that there was a login on that tty from the remote host. */ 867 if (!use_privsep) 868 record_login(pid, s->tty, pw->pw_name, pw->pw_uid, 869 get_remote_name_or_ip(utmp_len, 870 options.use_dns), 871 (struct sockaddr *)&from, fromlen); 872 873#ifdef USE_PAM 874 /* 875 * If password change is needed, do it now. 876 * This needs to occur before the ~/.hushlogin check. 877 */ 878 if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) { 879 display_loginmsg(); 880 do_pam_chauthtok(); 881 s->authctxt->force_pwchange = 0; 882 /* XXX - signal [net] parent to enable forwardings */ 883 } 884#endif 885 886 if (check_quietlogin(s, command)) 887 return; 888 889 display_loginmsg(); 890 891 do_motd(); 892} 893 894/* 895 * Display the message of the day. 896 */ 897void 898do_motd(void) 899{ 900 FILE *f; 901 char buf[256]; 902 903 if (options.print_motd) { 904#ifdef HAVE_LOGIN_CAP 905 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd", 906 "/etc/motd"), "r"); 907#else 908 f = fopen("/etc/motd", "r"); 909#endif 910 if (f) { 911 while (fgets(buf, sizeof(buf), f)) 912 fputs(buf, stdout); 913 fclose(f); 914 } 915 } 916} 917 918 919/* 920 * Check for quiet login, either .hushlogin or command given. 921 */ 922int 923check_quietlogin(Session *s, const char *command) 924{ 925 char buf[256]; 926 struct passwd *pw = s->pw; 927 struct stat st; 928 929 /* Return 1 if .hushlogin exists or a command given. */ 930 if (command != NULL) 931 return 1; 932 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir); 933#ifdef HAVE_LOGIN_CAP 934 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0) 935 return 1; 936#else 937 if (stat(buf, &st) >= 0) 938 return 1; 939#endif 940 return 0; 941} 942 943/* 944 * Sets the value of the given variable in the environment. If the variable 945 * already exists, its value is overridden. 946 */ 947void 948child_set_env(char ***envp, u_int *envsizep, const char *name, 949 const char *value) 950{ 951 char **env; 952 u_int envsize; 953 u_int i, namelen; 954 955 /* 956 * If we're passed an uninitialized list, allocate a single null 957 * entry before continuing. 958 */ 959 if (*envp == NULL && *envsizep == 0) { 960 *envp = xmalloc(sizeof(char *)); 961 *envp[0] = NULL; 962 *envsizep = 1; 963 } 964 965 /* 966 * Find the slot where the value should be stored. If the variable 967 * already exists, we reuse the slot; otherwise we append a new slot 968 * at the end of the array, expanding if necessary. 969 */ 970 env = *envp; 971 namelen = strlen(name); 972 for (i = 0; env[i]; i++) 973 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=') 974 break; 975 if (env[i]) { 976 /* Reuse the slot. */ 977 xfree(env[i]); 978 } else { 979 /* New variable. Expand if necessary. */ 980 envsize = *envsizep; 981 if (i >= envsize - 1) { 982 if (envsize >= 1000) 983 fatal("child_set_env: too many env vars"); 984 envsize += 50; 985 env = (*envp) = xrealloc(env, envsize, sizeof(char *)); 986 *envsizep = envsize; 987 } 988 /* Need to set the NULL pointer at end of array beyond the new slot. */ 989 env[i + 1] = NULL; 990 } 991 992 /* Allocate space and format the variable in the appropriate slot. */ 993 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1); 994 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value); 995} 996 997/* 998 * Reads environment variables from the given file and adds/overrides them 999 * into the environment. If the file does not exist, this does nothing. 1000 * Otherwise, it must consist of empty lines, comments (line starts with '#') 1001 * and assignments of the form name=value. No other forms are allowed. 1002 */ 1003static void 1004read_environment_file(char ***env, u_int *envsize, 1005 const char *filename) 1006{ 1007 FILE *f; 1008 char buf[4096]; 1009 char *cp, *value; 1010 u_int lineno = 0; 1011 1012 f = fopen(filename, "r"); 1013 if (!f) 1014 return; 1015 1016 while (fgets(buf, sizeof(buf), f)) { 1017 if (++lineno > 1000) 1018 fatal("Too many lines in environment file %s", filename); 1019 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++) 1020 ; 1021 if (!*cp || *cp == '#' || *cp == '\n') 1022 continue; 1023 1024 cp[strcspn(cp, "\n")] = '\0'; 1025 1026 value = strchr(cp, '='); 1027 if (value == NULL) { 1028 fprintf(stderr, "Bad line %u in %.100s\n", lineno, 1029 filename); 1030 continue; 1031 } 1032 /* 1033 * Replace the equals sign by nul, and advance value to 1034 * the value string. 1035 */ 1036 *value = '\0'; 1037 value++; 1038 child_set_env(env, envsize, cp, value); 1039 } 1040 fclose(f); 1041} 1042 1043#ifdef HAVE_ETC_DEFAULT_LOGIN 1044/* 1045 * Return named variable from specified environment, or NULL if not present. 1046 */ 1047static char * 1048child_get_env(char **env, const char *name) 1049{ 1050 int i; 1051 size_t len; 1052 1053 len = strlen(name); 1054 for (i=0; env[i] != NULL; i++) 1055 if (strncmp(name, env[i], len) == 0 && env[i][len] == '=') 1056 return(env[i] + len + 1); 1057 return NULL; 1058} 1059 1060/* 1061 * Read /etc/default/login. 1062 * We pick up the PATH (or SUPATH for root) and UMASK. 1063 */ 1064static void 1065read_etc_default_login(char ***env, u_int *envsize, uid_t uid) 1066{ 1067 char **tmpenv = NULL, *var; 1068 u_int i, tmpenvsize = 0; 1069 u_long mask; 1070 1071 /* 1072 * We don't want to copy the whole file to the child's environment, 1073 * so we use a temporary environment and copy the variables we're 1074 * interested in. 1075 */ 1076 read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login"); 1077 1078 if (tmpenv == NULL) 1079 return; 1080 1081 if (uid == 0) 1082 var = child_get_env(tmpenv, "SUPATH"); 1083 else 1084 var = child_get_env(tmpenv, "PATH"); 1085 if (var != NULL) 1086 child_set_env(env, envsize, "PATH", var); 1087 1088 if ((var = child_get_env(tmpenv, "UMASK")) != NULL) 1089 if (sscanf(var, "%5lo", &mask) == 1) 1090 umask((mode_t)mask); 1091 1092 for (i = 0; tmpenv[i] != NULL; i++) 1093 xfree(tmpenv[i]); 1094 xfree(tmpenv); 1095} 1096#endif /* HAVE_ETC_DEFAULT_LOGIN */ 1097 1098void 1099copy_environment(char **source, char ***env, u_int *envsize) 1100{ 1101 char *var_name, *var_val; 1102 int i; 1103 1104 if (source == NULL) 1105 return; 1106 1107 for(i = 0; source[i] != NULL; i++) { 1108 var_name = xstrdup(source[i]); 1109 if ((var_val = strstr(var_name, "=")) == NULL) { 1110 xfree(var_name); 1111 continue; 1112 } 1113 *var_val++ = '\0'; 1114 1115 debug3("Copy environment: %s=%s", var_name, var_val); 1116 child_set_env(env, envsize, var_name, var_val); 1117 1118 xfree(var_name); 1119 } 1120} 1121 1122static char ** 1123do_setup_env(Session *s, const char *shell) 1124{ 1125 char buf[256]; 1126 u_int i, envsize; 1127 char **env, *laddr; 1128 struct passwd *pw = s->pw; 1129#if !defined (HAVE_LOGIN_CAP) && !defined (HAVE_CYGWIN) 1130 char *path = NULL; 1131#endif 1132 1133 /* Initialize the environment. */ 1134 envsize = 100; 1135 env = xcalloc(envsize, sizeof(char *)); 1136 env[0] = NULL; 1137 1138#ifdef HAVE_CYGWIN 1139 /* 1140 * The Windows environment contains some setting which are 1141 * important for a running system. They must not be dropped. 1142 */ 1143 { 1144 char **p; 1145 1146 p = fetch_windows_environment(); 1147 copy_environment(p, &env, &envsize); 1148 free_windows_environment(p); 1149 } 1150#endif 1151 1152#ifdef GSSAPI 1153 /* Allow any GSSAPI methods that we've used to alter 1154 * the childs environment as they see fit 1155 */ 1156 ssh_gssapi_do_child(&env, &envsize); 1157#endif 1158 1159 if (!options.use_login) { 1160 /* Set basic environment. */ 1161 for (i = 0; i < s->num_env; i++) 1162 child_set_env(&env, &envsize, s->env[i].name, 1163 s->env[i].val); 1164 1165 child_set_env(&env, &envsize, "USER", pw->pw_name); 1166 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name); 1167#ifdef _AIX 1168 child_set_env(&env, &envsize, "LOGIN", pw->pw_name); 1169#endif 1170 child_set_env(&env, &envsize, "HOME", pw->pw_dir); 1171#ifdef HAVE_LOGIN_CAP 1172 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0) 1173 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH); 1174 else 1175 child_set_env(&env, &envsize, "PATH", getenv("PATH")); 1176#else /* HAVE_LOGIN_CAP */ 1177# ifndef HAVE_CYGWIN 1178 /* 1179 * There's no standard path on Windows. The path contains 1180 * important components pointing to the system directories, 1181 * needed for loading shared libraries. So the path better 1182 * remains intact here. 1183 */ 1184# ifdef HAVE_ETC_DEFAULT_LOGIN 1185 read_etc_default_login(&env, &envsize, pw->pw_uid); 1186 path = child_get_env(env, "PATH"); 1187# endif /* HAVE_ETC_DEFAULT_LOGIN */ 1188 if (path == NULL || *path == '\0') { 1189 child_set_env(&env, &envsize, "PATH", 1190 s->pw->pw_uid == 0 ? 1191 SUPERUSER_PATH : _PATH_STDPATH); 1192 } 1193# endif /* HAVE_CYGWIN */ 1194#endif /* HAVE_LOGIN_CAP */ 1195 1196 snprintf(buf, sizeof buf, "%.200s/%.50s", 1197 _PATH_MAILDIR, pw->pw_name); 1198 child_set_env(&env, &envsize, "MAIL", buf); 1199 1200 /* Normal systems set SHELL by default. */ 1201 child_set_env(&env, &envsize, "SHELL", shell); 1202 } 1203 if (getenv("TZ")) 1204 child_set_env(&env, &envsize, "TZ", getenv("TZ")); 1205 1206 /* Set custom environment options from RSA authentication. */ 1207 if (!options.use_login) { 1208 while (custom_environment) { 1209 struct envstring *ce = custom_environment; 1210 char *str = ce->s; 1211 1212 for (i = 0; str[i] != '=' && str[i]; i++) 1213 ; 1214 if (str[i] == '=') { 1215 str[i] = 0; 1216 child_set_env(&env, &envsize, str, str + i + 1); 1217 } 1218 custom_environment = ce->next; 1219 xfree(ce->s); 1220 xfree(ce); 1221 } 1222 } 1223 1224 /* SSH_CLIENT deprecated */ 1225 snprintf(buf, sizeof buf, "%.50s %d %d", 1226 get_remote_ipaddr(), get_remote_port(), get_local_port()); 1227 child_set_env(&env, &envsize, "SSH_CLIENT", buf); 1228 1229 laddr = get_local_ipaddr(packet_get_connection_in()); 1230 snprintf(buf, sizeof buf, "%.50s %d %.50s %d", 1231 get_remote_ipaddr(), get_remote_port(), laddr, get_local_port()); 1232 xfree(laddr); 1233 child_set_env(&env, &envsize, "SSH_CONNECTION", buf); 1234 1235 if (s->ttyfd != -1) 1236 child_set_env(&env, &envsize, "SSH_TTY", s->tty); 1237 if (s->term) 1238 child_set_env(&env, &envsize, "TERM", s->term); 1239 if (s->display) 1240 child_set_env(&env, &envsize, "DISPLAY", s->display); 1241 if (original_command) 1242 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND", 1243 original_command); 1244 1245#ifdef _UNICOS 1246 if (cray_tmpdir[0] != '\0') 1247 child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir); 1248#endif /* _UNICOS */ 1249 1250 /* 1251 * Since we clear KRB5CCNAME at startup, if it's set now then it 1252 * must have been set by a native authentication method (eg AIX or 1253 * SIA), so copy it to the child. 1254 */ 1255 { 1256 char *cp; 1257 1258 if ((cp = getenv("KRB5CCNAME")) != NULL) 1259 child_set_env(&env, &envsize, "KRB5CCNAME", cp); 1260 } 1261 1262#ifdef _AIX 1263 { 1264 char *cp; 1265 1266 if ((cp = getenv("AUTHSTATE")) != NULL) 1267 child_set_env(&env, &envsize, "AUTHSTATE", cp); 1268 read_environment_file(&env, &envsize, "/etc/environment"); 1269 } 1270#endif 1271#ifdef KRB5 1272 if (s->authctxt->krb5_ccname) 1273 child_set_env(&env, &envsize, "KRB5CCNAME", 1274 s->authctxt->krb5_ccname); 1275#endif 1276#ifdef USE_PAM 1277 /* 1278 * Pull in any environment variables that may have 1279 * been set by PAM. 1280 */ 1281 if (options.use_pam) { 1282 char **p; 1283 1284 p = fetch_pam_child_environment(); 1285 copy_environment(p, &env, &envsize); 1286 free_pam_environment(p); 1287 1288 p = fetch_pam_environment(); 1289 copy_environment(p, &env, &envsize); 1290 free_pam_environment(p); 1291 } 1292#endif /* USE_PAM */ 1293 1294 if (auth_sock_name != NULL) 1295 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME, 1296 auth_sock_name); 1297 1298 /* read $HOME/.ssh/environment. */ 1299 if (options.permit_user_env && !options.use_login) { 1300 snprintf(buf, sizeof buf, "%.200s/.ssh/environment", 1301 strcmp(pw->pw_dir, "/") ? pw->pw_dir : ""); 1302 read_environment_file(&env, &envsize, buf); 1303 } 1304 if (debug_flag) { 1305 /* dump the environment */ 1306 fprintf(stderr, "Environment:\n"); 1307 for (i = 0; env[i]; i++) 1308 fprintf(stderr, " %.200s\n", env[i]); 1309 } 1310 return env; 1311} 1312 1313/* 1314 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found 1315 * first in this order). 1316 */ 1317static void 1318do_rc_files(Session *s, const char *shell) 1319{ 1320 FILE *f = NULL; 1321 char cmd[1024]; 1322 int do_xauth; 1323 struct stat st; 1324 1325 do_xauth = 1326 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL; 1327 1328 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */ 1329 if (!s->is_subsystem && options.adm_forced_command == NULL && 1330 !no_user_rc && stat(_PATH_SSH_USER_RC, &st) >= 0) { 1331 snprintf(cmd, sizeof cmd, "%s -c '%s %s'", 1332 shell, _PATH_BSHELL, _PATH_SSH_USER_RC); 1333 if (debug_flag) 1334 fprintf(stderr, "Running %s\n", cmd); 1335 f = popen(cmd, "w"); 1336 if (f) { 1337 if (do_xauth) 1338 fprintf(f, "%s %s\n", s->auth_proto, 1339 s->auth_data); 1340 pclose(f); 1341 } else 1342 fprintf(stderr, "Could not run %s\n", 1343 _PATH_SSH_USER_RC); 1344 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) { 1345 if (debug_flag) 1346 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL, 1347 _PATH_SSH_SYSTEM_RC); 1348 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w"); 1349 if (f) { 1350 if (do_xauth) 1351 fprintf(f, "%s %s\n", s->auth_proto, 1352 s->auth_data); 1353 pclose(f); 1354 } else 1355 fprintf(stderr, "Could not run %s\n", 1356 _PATH_SSH_SYSTEM_RC); 1357 } else if (do_xauth && options.xauth_location != NULL) { 1358 /* Add authority data to .Xauthority if appropriate. */ 1359 if (debug_flag) { 1360 fprintf(stderr, 1361 "Running %.500s remove %.100s\n", 1362 options.xauth_location, s->auth_display); 1363 fprintf(stderr, 1364 "%.500s add %.100s %.100s %.100s\n", 1365 options.xauth_location, s->auth_display, 1366 s->auth_proto, s->auth_data); 1367 } 1368 snprintf(cmd, sizeof cmd, "%s -q -", 1369 options.xauth_location); 1370 f = popen(cmd, "w"); 1371 if (f) { 1372 fprintf(f, "remove %s\n", 1373 s->auth_display); 1374 fprintf(f, "add %s %s %s\n", 1375 s->auth_display, s->auth_proto, 1376 s->auth_data); 1377 pclose(f); 1378 } else { 1379 fprintf(stderr, "Could not run %s\n", 1380 cmd); 1381 } 1382 } 1383} 1384 1385static void 1386do_nologin(struct passwd *pw) 1387{ 1388 FILE *f = NULL; 1389 char buf[1024], *nl, *def_nl = _PATH_NOLOGIN; 1390 struct stat sb; 1391 1392#ifdef HAVE_LOGIN_CAP 1393 if (login_getcapbool(lc, "ignorenologin", 0) && pw->pw_uid) 1394 return; 1395 nl = login_getcapstr(lc, "nologin", def_nl, def_nl); 1396#else 1397 if (pw->pw_uid == 0) 1398 return; 1399 nl = def_nl; 1400#endif 1401 if (stat(nl, &sb) == -1) { 1402 if (nl != def_nl) 1403 xfree(nl); 1404 return; 1405 } 1406 1407 /* /etc/nologin exists. Print its contents if we can and exit. */ 1408 logit("User %.100s not allowed because %s exists", pw->pw_name, nl); 1409 if ((f = fopen(nl, "r")) != NULL) { 1410 while (fgets(buf, sizeof(buf), f)) 1411 fputs(buf, stderr); 1412 fclose(f); 1413 } 1414 exit(254); 1415} 1416 1417/* 1418 * Chroot into a directory after checking it for safety: all path components 1419 * must be root-owned directories with strict permissions. 1420 */ 1421static void 1422safely_chroot(const char *path, uid_t uid) 1423{ 1424 const char *cp; 1425 char component[MAXPATHLEN]; 1426 struct stat st; 1427 1428 if (*path != '/') 1429 fatal("chroot path does not begin at root"); 1430 if (strlen(path) >= sizeof(component)) 1431 fatal("chroot path too long"); 1432 1433 /* 1434 * Descend the path, checking that each component is a 1435 * root-owned directory with strict permissions. 1436 */ 1437 for (cp = path; cp != NULL;) { 1438 if ((cp = strchr(cp, '/')) == NULL) 1439 strlcpy(component, path, sizeof(component)); 1440 else { 1441 cp++; 1442 memcpy(component, path, cp - path); 1443 component[cp - path] = '\0'; 1444 } 1445 1446 debug3("%s: checking '%s'", __func__, component); 1447 1448 if (stat(component, &st) != 0) 1449 fatal("%s: stat(\"%s\"): %s", __func__, 1450 component, strerror(errno)); 1451 if (st.st_uid != 0 || (st.st_mode & 022) != 0) 1452 fatal("bad ownership or modes for chroot " 1453 "directory %s\"%s\"", 1454 cp == NULL ? "" : "component ", component); 1455 if (!S_ISDIR(st.st_mode)) 1456 fatal("chroot path %s\"%s\" is not a directory", 1457 cp == NULL ? "" : "component ", component); 1458 1459 } 1460 1461 if (chdir(path) == -1) 1462 fatal("Unable to chdir to chroot path \"%s\": " 1463 "%s", path, strerror(errno)); 1464 if (chroot(path) == -1) 1465 fatal("chroot(\"%s\"): %s", path, strerror(errno)); 1466 if (chdir("/") == -1) 1467 fatal("%s: chdir(/) after chroot: %s", 1468 __func__, strerror(errno)); 1469 verbose("Changed root directory to \"%s\"", path); 1470} 1471 1472/* Set login name, uid, gid, and groups. */ 1473void 1474do_setusercontext(struct passwd *pw) 1475{ 1476 char *chroot_path, *tmp; 1477 1478 platform_setusercontext(pw); 1479 1480 if (platform_privileged_uidswap()) { 1481#ifdef HAVE_LOGIN_CAP 1482 if (setusercontext(lc, pw, pw->pw_uid, 1483 (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) { 1484 perror("unable to set user context"); 1485 exit(1); 1486 } 1487#else 1488 if (setlogin(pw->pw_name) < 0) 1489 error("setlogin failed: %s", strerror(errno)); 1490 if (setgid(pw->pw_gid) < 0) { 1491 perror("setgid"); 1492 exit(1); 1493 } 1494 /* Initialize the group list. */ 1495 if (initgroups(pw->pw_name, pw->pw_gid) < 0) { 1496 perror("initgroups"); 1497 exit(1); 1498 } 1499#ifndef ANDROID 1500 /* FIXME - Android doesn't have this */ 1501 endgrent(); 1502#endif 1503#endif 1504 1505 platform_setusercontext_post_groups(pw); 1506 1507 if (options.chroot_directory != NULL && 1508 strcasecmp(options.chroot_directory, "none") != 0) { 1509 tmp = tilde_expand_filename(options.chroot_directory, 1510 pw->pw_uid); 1511 chroot_path = percent_expand(tmp, "h", pw->pw_dir, 1512 "u", pw->pw_name, (char *)NULL); 1513 safely_chroot(chroot_path, pw->pw_uid); 1514 free(tmp); 1515 free(chroot_path); 1516 } 1517 1518#ifdef HAVE_LOGIN_CAP 1519 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) { 1520 perror("unable to set user context (setuser)"); 1521 exit(1); 1522 } 1523#else 1524 /* Permanently switch to the desired uid. */ 1525 permanently_set_uid(pw); 1526#endif 1527 } 1528 1529 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid) 1530 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid); 1531} 1532 1533static void 1534do_pwchange(Session *s) 1535{ 1536 fflush(NULL); 1537 fprintf(stderr, "WARNING: Your password has expired.\n"); 1538 if (s->ttyfd != -1) { 1539 fprintf(stderr, 1540 "You must change your password now and login again!\n"); 1541#ifdef WITH_SELINUX 1542 setexeccon(NULL); 1543#endif 1544#ifdef PASSWD_NEEDS_USERNAME 1545 execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name, 1546 (char *)NULL); 1547#else 1548 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL); 1549#endif 1550 perror("passwd"); 1551 } else { 1552 fprintf(stderr, 1553 "Password change required but no TTY available.\n"); 1554 } 1555 exit(1); 1556} 1557 1558static void 1559launch_login(struct passwd *pw, const char *hostname) 1560{ 1561 /* Launch login(1). */ 1562 1563 execl(LOGIN_PROGRAM, "login", "-h", hostname, 1564#ifdef xxxLOGIN_NEEDS_TERM 1565 (s->term ? s->term : "unknown"), 1566#endif /* LOGIN_NEEDS_TERM */ 1567#ifdef LOGIN_NO_ENDOPT 1568 "-p", "-f", pw->pw_name, (char *)NULL); 1569#else 1570 "-p", "-f", "--", pw->pw_name, (char *)NULL); 1571#endif 1572 1573 /* Login couldn't be executed, die. */ 1574 1575 perror("login"); 1576 exit(1); 1577} 1578 1579static void 1580child_close_fds(void) 1581{ 1582 if (packet_get_connection_in() == packet_get_connection_out()) 1583 close(packet_get_connection_in()); 1584 else { 1585 close(packet_get_connection_in()); 1586 close(packet_get_connection_out()); 1587 } 1588 /* 1589 * Close all descriptors related to channels. They will still remain 1590 * open in the parent. 1591 */ 1592 /* XXX better use close-on-exec? -markus */ 1593 channel_close_all(); 1594 1595 /* 1596 * Close any extra file descriptors. Note that there may still be 1597 * descriptors left by system functions. They will be closed later. 1598 */ 1599 endpwent(); 1600 1601 /* 1602 * Close any extra open file descriptors so that we don't have them 1603 * hanging around in clients. Note that we want to do this after 1604 * initgroups, because at least on Solaris 2.3 it leaves file 1605 * descriptors open. 1606 */ 1607 closefrom(STDERR_FILENO + 1); 1608} 1609 1610/* 1611 * Performs common processing for the child, such as setting up the 1612 * environment, closing extra file descriptors, setting the user and group 1613 * ids, and executing the command or shell. 1614 */ 1615#define ARGV_MAX 10 1616void 1617do_child(Session *s, const char *command) 1618{ 1619 extern char **environ; 1620 char **env; 1621 char *argv[ARGV_MAX]; 1622 const char *shell, *shell0, *hostname = NULL; 1623 struct passwd *pw = s->pw; 1624 int r = 0; 1625 1626 /* remove hostkey from the child's memory */ 1627 destroy_sensitive_data(); 1628 1629 /* Force a password change */ 1630 if (s->authctxt->force_pwchange) { 1631 do_setusercontext(pw); 1632 child_close_fds(); 1633 do_pwchange(s); 1634 exit(1); 1635 } 1636 1637 /* login(1) is only called if we execute the login shell */ 1638 if (options.use_login && command != NULL) 1639 options.use_login = 0; 1640 1641#ifdef _UNICOS 1642 cray_setup(pw->pw_uid, pw->pw_name, command); 1643#endif /* _UNICOS */ 1644 1645 /* 1646 * Login(1) does this as well, and it needs uid 0 for the "-h" 1647 * switch, so we let login(1) to this for us. 1648 */ 1649 if (!options.use_login) { 1650#ifdef HAVE_OSF_SIA 1651 session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty); 1652 if (!check_quietlogin(s, command)) 1653 do_motd(); 1654#else /* HAVE_OSF_SIA */ 1655 /* When PAM is enabled we rely on it to do the nologin check */ 1656 if (!options.use_pam) 1657 do_nologin(pw); 1658 do_setusercontext(pw); 1659 /* 1660 * PAM session modules in do_setusercontext may have 1661 * generated messages, so if this in an interactive 1662 * login then display them too. 1663 */ 1664 if (!check_quietlogin(s, command)) 1665 display_loginmsg(); 1666#endif /* HAVE_OSF_SIA */ 1667 } 1668 1669#ifdef USE_PAM 1670 if (options.use_pam && !options.use_login && !is_pam_session_open()) { 1671 debug3("PAM session not opened, exiting"); 1672 display_loginmsg(); 1673 exit(254); 1674 } 1675#endif 1676 1677 /* 1678 * Get the shell from the password data. An empty shell field is 1679 * legal, and means /bin/sh. 1680 */ 1681 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell; 1682 1683 /* 1684 * Make sure $SHELL points to the shell from the password file, 1685 * even if shell is overridden from login.conf 1686 */ 1687 env = do_setup_env(s, shell); 1688 1689#ifdef HAVE_LOGIN_CAP 1690 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell); 1691#endif 1692 1693 /* we have to stash the hostname before we close our socket. */ 1694 if (options.use_login) 1695 hostname = get_remote_name_or_ip(utmp_len, 1696 options.use_dns); 1697 /* 1698 * Close the connection descriptors; note that this is the child, and 1699 * the server will still have the socket open, and it is important 1700 * that we do not shutdown it. Note that the descriptors cannot be 1701 * closed before building the environment, as we call 1702 * get_remote_ipaddr there. 1703 */ 1704 child_close_fds(); 1705 1706 /* 1707 * Must take new environment into use so that .ssh/rc, 1708 * /etc/ssh/sshrc and xauth are run in the proper environment. 1709 */ 1710 environ = env; 1711 1712#if defined(KRB5) && defined(USE_AFS) 1713 /* 1714 * At this point, we check to see if AFS is active and if we have 1715 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see 1716 * if we can (and need to) extend the ticket into an AFS token. If 1717 * we don't do this, we run into potential problems if the user's 1718 * home directory is in AFS and it's not world-readable. 1719 */ 1720 1721 if (options.kerberos_get_afs_token && k_hasafs() && 1722 (s->authctxt->krb5_ctx != NULL)) { 1723 char cell[64]; 1724 1725 debug("Getting AFS token"); 1726 1727 k_setpag(); 1728 1729 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0) 1730 krb5_afslog(s->authctxt->krb5_ctx, 1731 s->authctxt->krb5_fwd_ccache, cell, NULL); 1732 1733 krb5_afslog_home(s->authctxt->krb5_ctx, 1734 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir); 1735 } 1736#endif 1737 1738 /* Change current directory to the user's home directory. */ 1739 if (chdir(pw->pw_dir) < 0) { 1740 /* Suppress missing homedir warning for chroot case */ 1741#ifdef HAVE_LOGIN_CAP 1742 r = login_getcapbool(lc, "requirehome", 0); 1743#endif 1744 if (r || options.chroot_directory == NULL || 1745 strcasecmp(options.chroot_directory, "none") == 0) 1746 fprintf(stderr, "Could not chdir to home " 1747 "directory %s: %s\n", pw->pw_dir, 1748 strerror(errno)); 1749 if (r) 1750 exit(1); 1751 } 1752 1753 closefrom(STDERR_FILENO + 1); 1754 1755 if (!options.use_login) 1756 do_rc_files(s, shell); 1757 1758 /* restore SIGPIPE for child */ 1759 signal(SIGPIPE, SIG_DFL); 1760 1761 if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) { 1762 printf("This service allows sftp connections only.\n"); 1763 fflush(NULL); 1764 exit(1); 1765 } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) { 1766 extern int optind, optreset; 1767 int i; 1768 char *p, *args; 1769 1770 setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME); 1771 args = xstrdup(command ? command : "sftp-server"); 1772 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " "))) 1773 if (i < ARGV_MAX - 1) 1774 argv[i++] = p; 1775 argv[i] = NULL; 1776 optind = optreset = 1; 1777 __progname = argv[0]; 1778#ifdef WITH_SELINUX 1779 ssh_selinux_change_context("sftpd_t"); 1780#endif 1781 exit(sftp_server_main(i, argv, s->pw)); 1782 } 1783 1784 fflush(NULL); 1785 1786 if (options.use_login) { 1787 launch_login(pw, hostname); 1788 /* NEVERREACHED */ 1789 } 1790 1791 /* Get the last component of the shell name. */ 1792 if ((shell0 = strrchr(shell, '/')) != NULL) 1793 shell0++; 1794 else 1795 shell0 = shell; 1796 1797 /* 1798 * If we have no command, execute the shell. In this case, the shell 1799 * name to be passed in argv[0] is preceded by '-' to indicate that 1800 * this is a login shell. 1801 */ 1802 if (!command) { 1803 char argv0[256]; 1804 1805 /* Start the shell. Set initial character to '-'. */ 1806 argv0[0] = '-'; 1807 1808 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1) 1809 >= sizeof(argv0) - 1) { 1810 errno = EINVAL; 1811 perror(shell); 1812 exit(1); 1813 } 1814 1815 /* Execute the shell. */ 1816 argv[0] = argv0; 1817 argv[1] = NULL; 1818 execve(shell, argv, env); 1819 1820 /* Executing the shell failed. */ 1821 perror(shell); 1822 exit(1); 1823 } 1824 /* 1825 * Execute the command using the user's shell. This uses the -c 1826 * option to execute the command. 1827 */ 1828 argv[0] = (char *) shell0; 1829 argv[1] = "-c"; 1830 argv[2] = (char *) command; 1831 argv[3] = NULL; 1832 execve(shell, argv, env); 1833 perror(shell); 1834 exit(1); 1835} 1836 1837void 1838session_unused(int id) 1839{ 1840 debug3("%s: session id %d unused", __func__, id); 1841 if (id >= options.max_sessions || 1842 id >= sessions_nalloc) { 1843 fatal("%s: insane session id %d (max %d nalloc %d)", 1844 __func__, id, options.max_sessions, sessions_nalloc); 1845 } 1846 bzero(&sessions[id], sizeof(*sessions)); 1847 sessions[id].self = id; 1848 sessions[id].used = 0; 1849 sessions[id].chanid = -1; 1850 sessions[id].ptyfd = -1; 1851 sessions[id].ttyfd = -1; 1852 sessions[id].ptymaster = -1; 1853 sessions[id].x11_chanids = NULL; 1854 sessions[id].next_unused = sessions_first_unused; 1855 sessions_first_unused = id; 1856} 1857 1858Session * 1859session_new(void) 1860{ 1861 Session *s, *tmp; 1862 1863 if (sessions_first_unused == -1) { 1864 if (sessions_nalloc >= options.max_sessions) 1865 return NULL; 1866 debug2("%s: allocate (allocated %d max %d)", 1867 __func__, sessions_nalloc, options.max_sessions); 1868 tmp = xrealloc(sessions, sessions_nalloc + 1, 1869 sizeof(*sessions)); 1870 if (tmp == NULL) { 1871 error("%s: cannot allocate %d sessions", 1872 __func__, sessions_nalloc + 1); 1873 return NULL; 1874 } 1875 sessions = tmp; 1876 session_unused(sessions_nalloc++); 1877 } 1878 1879 if (sessions_first_unused >= sessions_nalloc || 1880 sessions_first_unused < 0) { 1881 fatal("%s: insane first_unused %d max %d nalloc %d", 1882 __func__, sessions_first_unused, options.max_sessions, 1883 sessions_nalloc); 1884 } 1885 1886 s = &sessions[sessions_first_unused]; 1887 if (s->used) { 1888 fatal("%s: session %d already used", 1889 __func__, sessions_first_unused); 1890 } 1891 sessions_first_unused = s->next_unused; 1892 s->used = 1; 1893 s->next_unused = -1; 1894 debug("session_new: session %d", s->self); 1895 1896 return s; 1897} 1898 1899static void 1900session_dump(void) 1901{ 1902 int i; 1903 for (i = 0; i < sessions_nalloc; i++) { 1904 Session *s = &sessions[i]; 1905 1906 debug("dump: used %d next_unused %d session %d %p " 1907 "channel %d pid %ld", 1908 s->used, 1909 s->next_unused, 1910 s->self, 1911 s, 1912 s->chanid, 1913 (long)s->pid); 1914 } 1915} 1916 1917int 1918session_open(Authctxt *authctxt, int chanid) 1919{ 1920 Session *s = session_new(); 1921 debug("session_open: channel %d", chanid); 1922 if (s == NULL) { 1923 error("no more sessions"); 1924 return 0; 1925 } 1926 s->authctxt = authctxt; 1927 s->pw = authctxt->pw; 1928 if (s->pw == NULL || !authctxt->valid) 1929 fatal("no user for session %d", s->self); 1930 debug("session_open: session %d: link with channel %d", s->self, chanid); 1931 s->chanid = chanid; 1932 return 1; 1933} 1934 1935Session * 1936session_by_tty(char *tty) 1937{ 1938 int i; 1939 for (i = 0; i < sessions_nalloc; i++) { 1940 Session *s = &sessions[i]; 1941 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) { 1942 debug("session_by_tty: session %d tty %s", i, tty); 1943 return s; 1944 } 1945 } 1946 debug("session_by_tty: unknown tty %.100s", tty); 1947 session_dump(); 1948 return NULL; 1949} 1950 1951static Session * 1952session_by_channel(int id) 1953{ 1954 int i; 1955 for (i = 0; i < sessions_nalloc; i++) { 1956 Session *s = &sessions[i]; 1957 if (s->used && s->chanid == id) { 1958 debug("session_by_channel: session %d channel %d", 1959 i, id); 1960 return s; 1961 } 1962 } 1963 debug("session_by_channel: unknown channel %d", id); 1964 session_dump(); 1965 return NULL; 1966} 1967 1968static Session * 1969session_by_x11_channel(int id) 1970{ 1971 int i, j; 1972 1973 for (i = 0; i < sessions_nalloc; i++) { 1974 Session *s = &sessions[i]; 1975 1976 if (s->x11_chanids == NULL || !s->used) 1977 continue; 1978 for (j = 0; s->x11_chanids[j] != -1; j++) { 1979 if (s->x11_chanids[j] == id) { 1980 debug("session_by_x11_channel: session %d " 1981 "channel %d", s->self, id); 1982 return s; 1983 } 1984 } 1985 } 1986 debug("session_by_x11_channel: unknown channel %d", id); 1987 session_dump(); 1988 return NULL; 1989} 1990 1991static Session * 1992session_by_pid(pid_t pid) 1993{ 1994 int i; 1995 debug("session_by_pid: pid %ld", (long)pid); 1996 for (i = 0; i < sessions_nalloc; i++) { 1997 Session *s = &sessions[i]; 1998 if (s->used && s->pid == pid) 1999 return s; 2000 } 2001 error("session_by_pid: unknown pid %ld", (long)pid); 2002 session_dump(); 2003 return NULL; 2004} 2005 2006static int 2007session_window_change_req(Session *s) 2008{ 2009 s->col = packet_get_int(); 2010 s->row = packet_get_int(); 2011 s->xpixel = packet_get_int(); 2012 s->ypixel = packet_get_int(); 2013 packet_check_eom(); 2014 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel); 2015 return 1; 2016} 2017 2018static int 2019session_pty_req(Session *s) 2020{ 2021 u_int len; 2022 int n_bytes; 2023 2024 if (no_pty_flag) { 2025 debug("Allocating a pty not permitted for this authentication."); 2026 return 0; 2027 } 2028 if (s->ttyfd != -1) { 2029 packet_disconnect("Protocol error: you already have a pty."); 2030 return 0; 2031 } 2032 2033 s->term = packet_get_string(&len); 2034 2035 if (compat20) { 2036 s->col = packet_get_int(); 2037 s->row = packet_get_int(); 2038 } else { 2039 s->row = packet_get_int(); 2040 s->col = packet_get_int(); 2041 } 2042 s->xpixel = packet_get_int(); 2043 s->ypixel = packet_get_int(); 2044 2045 if (strcmp(s->term, "") == 0) { 2046 xfree(s->term); 2047 s->term = NULL; 2048 } 2049 2050 /* Allocate a pty and open it. */ 2051 debug("Allocating pty."); 2052 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, 2053 sizeof(s->tty)))) { 2054 if (s->term) 2055 xfree(s->term); 2056 s->term = NULL; 2057 s->ptyfd = -1; 2058 s->ttyfd = -1; 2059 error("session_pty_req: session %d alloc failed", s->self); 2060 return 0; 2061 } 2062 debug("session_pty_req: session %d alloc %s", s->self, s->tty); 2063 2064 /* for SSH1 the tty modes length is not given */ 2065 if (!compat20) 2066 n_bytes = packet_remaining(); 2067 tty_parse_modes(s->ttyfd, &n_bytes); 2068 2069 if (!use_privsep) 2070 pty_setowner(s->pw, s->tty); 2071 2072 /* Set window size from the packet. */ 2073 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel); 2074 2075 packet_check_eom(); 2076 session_proctitle(s); 2077 return 1; 2078} 2079 2080static int 2081session_subsystem_req(Session *s) 2082{ 2083 struct stat st; 2084 u_int len; 2085 int success = 0; 2086 char *prog, *cmd, *subsys = packet_get_string(&len); 2087 u_int i; 2088 2089 packet_check_eom(); 2090 logit("subsystem request for %.100s by user %s", subsys, 2091 s->pw->pw_name); 2092 2093 for (i = 0; i < options.num_subsystems; i++) { 2094 if (strcmp(subsys, options.subsystem_name[i]) == 0) { 2095 prog = options.subsystem_command[i]; 2096 cmd = options.subsystem_args[i]; 2097 if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) { 2098 s->is_subsystem = SUBSYSTEM_INT_SFTP; 2099 debug("subsystem: %s", prog); 2100 } else { 2101 if (stat(prog, &st) < 0) 2102 debug("subsystem: cannot stat %s: %s", 2103 prog, strerror(errno)); 2104 s->is_subsystem = SUBSYSTEM_EXT; 2105 debug("subsystem: exec() %s", cmd); 2106 } 2107 success = do_exec(s, cmd) == 0; 2108 break; 2109 } 2110 } 2111 2112 if (!success) 2113 logit("subsystem request for %.100s failed, subsystem not found", 2114 subsys); 2115 2116 xfree(subsys); 2117 return success; 2118} 2119 2120static int 2121session_x11_req(Session *s) 2122{ 2123 int success; 2124 2125 if (s->auth_proto != NULL || s->auth_data != NULL) { 2126 error("session_x11_req: session %d: " 2127 "x11 forwarding already active", s->self); 2128 return 0; 2129 } 2130 s->single_connection = packet_get_char(); 2131 s->auth_proto = packet_get_string(NULL); 2132 s->auth_data = packet_get_string(NULL); 2133 s->screen = packet_get_int(); 2134 packet_check_eom(); 2135 2136 success = session_setup_x11fwd(s); 2137 if (!success) { 2138 xfree(s->auth_proto); 2139 xfree(s->auth_data); 2140 s->auth_proto = NULL; 2141 s->auth_data = NULL; 2142 } 2143 return success; 2144} 2145 2146static int 2147session_shell_req(Session *s) 2148{ 2149 packet_check_eom(); 2150 return do_exec(s, NULL) == 0; 2151} 2152 2153static int 2154session_exec_req(Session *s) 2155{ 2156 u_int len, success; 2157 2158 char *command = packet_get_string(&len); 2159 packet_check_eom(); 2160 success = do_exec(s, command) == 0; 2161 xfree(command); 2162 return success; 2163} 2164 2165static int 2166session_break_req(Session *s) 2167{ 2168 2169 packet_get_int(); /* ignored */ 2170 packet_check_eom(); 2171 2172 if (s->ttyfd == -1 || tcsendbreak(s->ttyfd, 0) < 0) 2173 return 0; 2174 return 1; 2175} 2176 2177static int 2178session_env_req(Session *s) 2179{ 2180 char *name, *val; 2181 u_int name_len, val_len, i; 2182 2183 name = packet_get_string(&name_len); 2184 val = packet_get_string(&val_len); 2185 packet_check_eom(); 2186 2187 /* Don't set too many environment variables */ 2188 if (s->num_env > 128) { 2189 debug2("Ignoring env request %s: too many env vars", name); 2190 goto fail; 2191 } 2192 2193 for (i = 0; i < options.num_accept_env; i++) { 2194 if (match_pattern(name, options.accept_env[i])) { 2195 debug2("Setting env %d: %s=%s", s->num_env, name, val); 2196 s->env = xrealloc(s->env, s->num_env + 1, 2197 sizeof(*s->env)); 2198 s->env[s->num_env].name = name; 2199 s->env[s->num_env].val = val; 2200 s->num_env++; 2201 return (1); 2202 } 2203 } 2204 debug2("Ignoring env request %s: disallowed name", name); 2205 2206 fail: 2207 xfree(name); 2208 xfree(val); 2209 return (0); 2210} 2211 2212static int 2213session_auth_agent_req(Session *s) 2214{ 2215 static int called = 0; 2216 packet_check_eom(); 2217 if (no_agent_forwarding_flag || !options.allow_agent_forwarding) { 2218 debug("session_auth_agent_req: no_agent_forwarding_flag"); 2219 return 0; 2220 } 2221 if (called) { 2222 return 0; 2223 } else { 2224 called = 1; 2225 return auth_input_request_forwarding(s->pw); 2226 } 2227} 2228 2229int 2230session_input_channel_req(Channel *c, const char *rtype) 2231{ 2232 int success = 0; 2233 Session *s; 2234 2235 if ((s = session_by_channel(c->self)) == NULL) { 2236 logit("session_input_channel_req: no session %d req %.100s", 2237 c->self, rtype); 2238 return 0; 2239 } 2240 debug("session_input_channel_req: session %d req %s", s->self, rtype); 2241 2242 /* 2243 * a session is in LARVAL state until a shell, a command 2244 * or a subsystem is executed 2245 */ 2246 if (c->type == SSH_CHANNEL_LARVAL) { 2247 if (strcmp(rtype, "shell") == 0) { 2248 success = session_shell_req(s); 2249 } else if (strcmp(rtype, "exec") == 0) { 2250 success = session_exec_req(s); 2251 } else if (strcmp(rtype, "pty-req") == 0) { 2252 success = session_pty_req(s); 2253 } else if (strcmp(rtype, "x11-req") == 0) { 2254 success = session_x11_req(s); 2255 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) { 2256 success = session_auth_agent_req(s); 2257 } else if (strcmp(rtype, "subsystem") == 0) { 2258 success = session_subsystem_req(s); 2259 } else if (strcmp(rtype, "env") == 0) { 2260 success = session_env_req(s); 2261 } 2262 } 2263 if (strcmp(rtype, "window-change") == 0) { 2264 success = session_window_change_req(s); 2265 } else if (strcmp(rtype, "break") == 0) { 2266 success = session_break_req(s); 2267 } 2268 2269 return success; 2270} 2271 2272void 2273session_set_fds(Session *s, int fdin, int fdout, int fderr, int ignore_fderr, 2274 int is_tty) 2275{ 2276 if (!compat20) 2277 fatal("session_set_fds: called for proto != 2.0"); 2278 /* 2279 * now that have a child and a pipe to the child, 2280 * we can activate our channel and register the fd's 2281 */ 2282 if (s->chanid == -1) 2283 fatal("no channel for session %d", s->self); 2284 channel_set_fds(s->chanid, 2285 fdout, fdin, fderr, 2286 ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ, 2287 1, is_tty, CHAN_SES_WINDOW_DEFAULT); 2288} 2289 2290/* 2291 * Function to perform pty cleanup. Also called if we get aborted abnormally 2292 * (e.g., due to a dropped connection). 2293 */ 2294void 2295session_pty_cleanup2(Session *s) 2296{ 2297 if (s == NULL) { 2298 error("session_pty_cleanup: no session"); 2299 return; 2300 } 2301 if (s->ttyfd == -1) 2302 return; 2303 2304 debug("session_pty_cleanup: session %d release %s", s->self, s->tty); 2305 2306 /* Record that the user has logged out. */ 2307 if (s->pid != 0) 2308 record_logout(s->pid, s->tty, s->pw->pw_name); 2309 2310 /* Release the pseudo-tty. */ 2311 if (getuid() == 0) 2312 pty_release(s->tty); 2313 2314 /* 2315 * Close the server side of the socket pairs. We must do this after 2316 * the pty cleanup, so that another process doesn't get this pty 2317 * while we're still cleaning up. 2318 */ 2319 if (s->ptymaster != -1 && close(s->ptymaster) < 0) 2320 error("close(s->ptymaster/%d): %s", 2321 s->ptymaster, strerror(errno)); 2322 2323 /* unlink pty from session */ 2324 s->ttyfd = -1; 2325} 2326 2327void 2328session_pty_cleanup(Session *s) 2329{ 2330 PRIVSEP(session_pty_cleanup2(s)); 2331} 2332 2333static char * 2334sig2name(int sig) 2335{ 2336#define SSH_SIG(x) if (sig == SIG ## x) return #x 2337 SSH_SIG(ABRT); 2338 SSH_SIG(ALRM); 2339 SSH_SIG(FPE); 2340 SSH_SIG(HUP); 2341 SSH_SIG(ILL); 2342 SSH_SIG(INT); 2343 SSH_SIG(KILL); 2344 SSH_SIG(PIPE); 2345 SSH_SIG(QUIT); 2346 SSH_SIG(SEGV); 2347 SSH_SIG(TERM); 2348 SSH_SIG(USR1); 2349 SSH_SIG(USR2); 2350#undef SSH_SIG 2351 return "SIG@openssh.com"; 2352} 2353 2354static void 2355session_close_x11(int id) 2356{ 2357 Channel *c; 2358 2359 if ((c = channel_by_id(id)) == NULL) { 2360 debug("session_close_x11: x11 channel %d missing", id); 2361 } else { 2362 /* Detach X11 listener */ 2363 debug("session_close_x11: detach x11 channel %d", id); 2364 channel_cancel_cleanup(id); 2365 if (c->ostate != CHAN_OUTPUT_CLOSED) 2366 chan_mark_dead(c); 2367 } 2368} 2369 2370static void 2371session_close_single_x11(int id, void *arg) 2372{ 2373 Session *s; 2374 u_int i; 2375 2376 debug3("session_close_single_x11: channel %d", id); 2377 channel_cancel_cleanup(id); 2378 if ((s = session_by_x11_channel(id)) == NULL) 2379 fatal("session_close_single_x11: no x11 channel %d", id); 2380 for (i = 0; s->x11_chanids[i] != -1; i++) { 2381 debug("session_close_single_x11: session %d: " 2382 "closing channel %d", s->self, s->x11_chanids[i]); 2383 /* 2384 * The channel "id" is already closing, but make sure we 2385 * close all of its siblings. 2386 */ 2387 if (s->x11_chanids[i] != id) 2388 session_close_x11(s->x11_chanids[i]); 2389 } 2390 xfree(s->x11_chanids); 2391 s->x11_chanids = NULL; 2392 if (s->display) { 2393 xfree(s->display); 2394 s->display = NULL; 2395 } 2396 if (s->auth_proto) { 2397 xfree(s->auth_proto); 2398 s->auth_proto = NULL; 2399 } 2400 if (s->auth_data) { 2401 xfree(s->auth_data); 2402 s->auth_data = NULL; 2403 } 2404 if (s->auth_display) { 2405 xfree(s->auth_display); 2406 s->auth_display = NULL; 2407 } 2408} 2409 2410static void 2411session_exit_message(Session *s, int status) 2412{ 2413 Channel *c; 2414 2415 if ((c = channel_lookup(s->chanid)) == NULL) 2416 fatal("session_exit_message: session %d: no channel %d", 2417 s->self, s->chanid); 2418 debug("session_exit_message: session %d channel %d pid %ld", 2419 s->self, s->chanid, (long)s->pid); 2420 2421 if (WIFEXITED(status)) { 2422 channel_request_start(s->chanid, "exit-status", 0); 2423 packet_put_int(WEXITSTATUS(status)); 2424 packet_send(); 2425 } else if (WIFSIGNALED(status)) { 2426 channel_request_start(s->chanid, "exit-signal", 0); 2427 packet_put_cstring(sig2name(WTERMSIG(status))); 2428#ifdef WCOREDUMP 2429 packet_put_char(WCOREDUMP(status)? 1 : 0); 2430#else /* WCOREDUMP */ 2431 packet_put_char(0); 2432#endif /* WCOREDUMP */ 2433 packet_put_cstring(""); 2434 packet_put_cstring(""); 2435 packet_send(); 2436 } else { 2437 /* Some weird exit cause. Just exit. */ 2438 packet_disconnect("wait returned status %04x.", status); 2439 } 2440 2441 /* disconnect channel */ 2442 debug("session_exit_message: release channel %d", s->chanid); 2443 2444 /* 2445 * Adjust cleanup callback attachment to send close messages when 2446 * the channel gets EOF. The session will be then be closed 2447 * by session_close_by_channel when the childs close their fds. 2448 */ 2449 channel_register_cleanup(c->self, session_close_by_channel, 1); 2450 2451 /* 2452 * emulate a write failure with 'chan_write_failed', nobody will be 2453 * interested in data we write. 2454 * Note that we must not call 'chan_read_failed', since there could 2455 * be some more data waiting in the pipe. 2456 */ 2457 if (c->ostate != CHAN_OUTPUT_CLOSED) 2458 chan_write_failed(c); 2459} 2460 2461void 2462session_close(Session *s) 2463{ 2464 u_int i; 2465 2466 debug("session_close: session %d pid %ld", s->self, (long)s->pid); 2467 if (s->ttyfd != -1) 2468 session_pty_cleanup(s); 2469 if (s->term) 2470 xfree(s->term); 2471 if (s->display) 2472 xfree(s->display); 2473 if (s->x11_chanids) 2474 xfree(s->x11_chanids); 2475 if (s->auth_display) 2476 xfree(s->auth_display); 2477 if (s->auth_data) 2478 xfree(s->auth_data); 2479 if (s->auth_proto) 2480 xfree(s->auth_proto); 2481 if (s->env != NULL) { 2482 for (i = 0; i < s->num_env; i++) { 2483 xfree(s->env[i].name); 2484 xfree(s->env[i].val); 2485 } 2486 xfree(s->env); 2487 } 2488 session_proctitle(s); 2489 session_unused(s->self); 2490} 2491 2492void 2493session_close_by_pid(pid_t pid, int status) 2494{ 2495 Session *s = session_by_pid(pid); 2496 if (s == NULL) { 2497 debug("session_close_by_pid: no session for pid %ld", 2498 (long)pid); 2499 return; 2500 } 2501 if (s->chanid != -1) 2502 session_exit_message(s, status); 2503 if (s->ttyfd != -1) 2504 session_pty_cleanup(s); 2505 s->pid = 0; 2506} 2507 2508/* 2509 * this is called when a channel dies before 2510 * the session 'child' itself dies 2511 */ 2512void 2513session_close_by_channel(int id, void *arg) 2514{ 2515 Session *s = session_by_channel(id); 2516 u_int i; 2517 2518 if (s == NULL) { 2519 debug("session_close_by_channel: no session for id %d", id); 2520 return; 2521 } 2522 debug("session_close_by_channel: channel %d child %ld", 2523 id, (long)s->pid); 2524 if (s->pid != 0) { 2525 debug("session_close_by_channel: channel %d: has child", id); 2526 /* 2527 * delay detach of session, but release pty, since 2528 * the fd's to the child are already closed 2529 */ 2530 if (s->ttyfd != -1) 2531 session_pty_cleanup(s); 2532 return; 2533 } 2534 /* detach by removing callback */ 2535 channel_cancel_cleanup(s->chanid); 2536 2537 /* Close any X11 listeners associated with this session */ 2538 if (s->x11_chanids != NULL) { 2539 for (i = 0; s->x11_chanids[i] != -1; i++) { 2540 session_close_x11(s->x11_chanids[i]); 2541 s->x11_chanids[i] = -1; 2542 } 2543 } 2544 2545 s->chanid = -1; 2546 session_close(s); 2547} 2548 2549void 2550session_destroy_all(void (*closefunc)(Session *)) 2551{ 2552 int i; 2553 for (i = 0; i < sessions_nalloc; i++) { 2554 Session *s = &sessions[i]; 2555 if (s->used) { 2556 if (closefunc != NULL) 2557 closefunc(s); 2558 else 2559 session_close(s); 2560 } 2561 } 2562} 2563 2564static char * 2565session_tty_list(void) 2566{ 2567 static char buf[1024]; 2568 int i; 2569 char *cp; 2570 2571 buf[0] = '\0'; 2572 for (i = 0; i < sessions_nalloc; i++) { 2573 Session *s = &sessions[i]; 2574 if (s->used && s->ttyfd != -1) { 2575 2576 if (strncmp(s->tty, "/dev/", 5) != 0) { 2577 cp = strrchr(s->tty, '/'); 2578 cp = (cp == NULL) ? s->tty : cp + 1; 2579 } else 2580 cp = s->tty + 5; 2581 2582 if (buf[0] != '\0') 2583 strlcat(buf, ",", sizeof buf); 2584 strlcat(buf, cp, sizeof buf); 2585 } 2586 } 2587 if (buf[0] == '\0') 2588 strlcpy(buf, "notty", sizeof buf); 2589 return buf; 2590} 2591 2592void 2593session_proctitle(Session *s) 2594{ 2595 if (s->pw == NULL) 2596 error("no user for session %d", s->self); 2597 else 2598 setproctitle("%s@%s", s->pw->pw_name, session_tty_list()); 2599} 2600 2601int 2602session_setup_x11fwd(Session *s) 2603{ 2604 struct stat st; 2605 char display[512], auth_display[512]; 2606 char hostname[MAXHOSTNAMELEN]; 2607 u_int i; 2608 2609 if (no_x11_forwarding_flag) { 2610 packet_send_debug("X11 forwarding disabled in user configuration file."); 2611 return 0; 2612 } 2613 if (!options.x11_forwarding) { 2614 debug("X11 forwarding disabled in server configuration file."); 2615 return 0; 2616 } 2617 if (!options.xauth_location || 2618 (stat(options.xauth_location, &st) == -1)) { 2619 packet_send_debug("No xauth program; cannot forward with spoofing."); 2620 return 0; 2621 } 2622 if (options.use_login) { 2623 packet_send_debug("X11 forwarding disabled; " 2624 "not compatible with UseLogin=yes."); 2625 return 0; 2626 } 2627 if (s->display != NULL) { 2628 debug("X11 display already set."); 2629 return 0; 2630 } 2631 if (x11_create_display_inet(options.x11_display_offset, 2632 options.x11_use_localhost, s->single_connection, 2633 &s->display_number, &s->x11_chanids) == -1) { 2634 debug("x11_create_display_inet failed."); 2635 return 0; 2636 } 2637 for (i = 0; s->x11_chanids[i] != -1; i++) { 2638 channel_register_cleanup(s->x11_chanids[i], 2639 session_close_single_x11, 0); 2640 } 2641 2642 /* Set up a suitable value for the DISPLAY variable. */ 2643 if (gethostname(hostname, sizeof(hostname)) < 0) 2644 fatal("gethostname: %.100s", strerror(errno)); 2645 /* 2646 * auth_display must be used as the displayname when the 2647 * authorization entry is added with xauth(1). This will be 2648 * different than the DISPLAY string for localhost displays. 2649 */ 2650 if (options.x11_use_localhost) { 2651 snprintf(display, sizeof display, "localhost:%u.%u", 2652 s->display_number, s->screen); 2653 snprintf(auth_display, sizeof auth_display, "unix:%u.%u", 2654 s->display_number, s->screen); 2655 s->display = xstrdup(display); 2656 s->auth_display = xstrdup(auth_display); 2657 } else { 2658#ifdef IPADDR_IN_DISPLAY 2659 struct hostent *he; 2660 struct in_addr my_addr; 2661 2662 he = gethostbyname(hostname); 2663 if (he == NULL) { 2664 error("Can't get IP address for X11 DISPLAY."); 2665 packet_send_debug("Can't get IP address for X11 DISPLAY."); 2666 return 0; 2667 } 2668 memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr)); 2669 snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr), 2670 s->display_number, s->screen); 2671#else 2672 snprintf(display, sizeof display, "%.400s:%u.%u", hostname, 2673 s->display_number, s->screen); 2674#endif 2675 s->display = xstrdup(display); 2676 s->auth_display = xstrdup(display); 2677 } 2678 2679 return 1; 2680} 2681 2682static void 2683do_authenticated2(Authctxt *authctxt) 2684{ 2685 server_loop2(authctxt); 2686} 2687 2688void 2689do_cleanup(Authctxt *authctxt) 2690{ 2691 static int called = 0; 2692 2693 debug("do_cleanup"); 2694 2695 /* no cleanup if we're in the child for login shell */ 2696 if (is_child) 2697 return; 2698 2699 /* avoid double cleanup */ 2700 if (called) 2701 return; 2702 called = 1; 2703 2704 if (authctxt == NULL) 2705 return; 2706 2707#ifdef USE_PAM 2708 if (options.use_pam) { 2709 sshpam_cleanup(); 2710 sshpam_thread_cleanup(); 2711 } 2712#endif 2713 2714 if (!authctxt->authenticated) 2715 return; 2716 2717#ifdef KRB5 2718 if (options.kerberos_ticket_cleanup && 2719 authctxt->krb5_ctx) 2720 krb5_cleanup_proc(authctxt); 2721#endif 2722 2723#ifdef GSSAPI 2724 if (compat20 && options.gss_cleanup_creds) 2725 ssh_gssapi_cleanup_creds(); 2726#endif 2727 2728 /* remove agent socket */ 2729 auth_sock_cleanup_proc(authctxt->pw); 2730 2731 /* 2732 * Cleanup ptys/utmp only if privsep is disabled, 2733 * or if running in monitor. 2734 */ 2735 if (!use_privsep || mm_is_monitor()) 2736 session_destroy_all(session_pty_cleanup2); 2737} 2738