session.c revision 1.1.1.10
1/* $OpenBSD: session.c,v 1.277 2015/01/16 06:40:12 deraadt 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 <sys/types.h> 37#include <sys/wait.h> 38#include <sys/un.h> 39#include <sys/stat.h> 40#include <sys/socket.h> 41#include <sys/queue.h> 42 43#include <errno.h> 44#include <fcntl.h> 45#include <grp.h> 46#include <login_cap.h> 47#include <netdb.h> 48#include <paths.h> 49#include <pwd.h> 50#include <signal.h> 51#include <stdio.h> 52#include <stdlib.h> 53#include <string.h> 54#include <unistd.h> 55#include <limits.h> 56 57#include "xmalloc.h" 58#include "ssh.h" 59#include "ssh1.h" 60#include "ssh2.h" 61#include "sshpty.h" 62#include "packet.h" 63#include "buffer.h" 64#include "match.h" 65#include "uidswap.h" 66#include "compat.h" 67#include "channels.h" 68#include "key.h" 69#include "cipher.h" 70#include "kex.h" 71#include "hostfile.h" 72#include "auth.h" 73#include "auth-options.h" 74#include "authfd.h" 75#include "pathnames.h" 76#include "log.h" 77#include "misc.h" 78#include "servconf.h" 79#include "sshlogin.h" 80#include "serverloop.h" 81#include "canohost.h" 82#include "session.h" 83#ifdef GSSAPI 84#include "ssh-gss.h" 85#endif 86#include "monitor_wrap.h" 87#include "sftp.h" 88 89#ifdef KRB5 90#include <kafs.h> 91#endif 92 93#define IS_INTERNAL_SFTP(c) \ 94 (!strncmp(c, INTERNAL_SFTP_NAME, sizeof(INTERNAL_SFTP_NAME) - 1) && \ 95 (c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\0' || \ 96 c[sizeof(INTERNAL_SFTP_NAME) - 1] == ' ' || \ 97 c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\t')) 98 99/* func */ 100 101Session *session_new(void); 102void session_set_fds(Session *, int, int, int, int, int); 103void session_pty_cleanup(Session *); 104void session_proctitle(Session *); 105int session_setup_x11fwd(Session *); 106int do_exec_pty(Session *, const char *); 107int do_exec_no_pty(Session *, const char *); 108int do_exec(Session *, const char *); 109void do_login(Session *, const char *); 110void do_child(Session *, const char *); 111void do_motd(void); 112int check_quietlogin(Session *, const char *); 113 114static void do_authenticated1(Authctxt *); 115static void do_authenticated2(Authctxt *); 116 117static int session_pty_req(Session *); 118 119/* import */ 120extern ServerOptions options; 121extern char *__progname; 122extern int log_stderr; 123extern int debug_flag; 124extern u_int utmp_len; 125extern int startup_pipe; 126extern void destroy_sensitive_data(void); 127extern Buffer loginmsg; 128 129/* original command from peer. */ 130const char *original_command = NULL; 131 132/* data */ 133static int sessions_first_unused = -1; 134static int sessions_nalloc = 0; 135static Session *sessions = NULL; 136 137#define SUBSYSTEM_NONE 0 138#define SUBSYSTEM_EXT 1 139#define SUBSYSTEM_INT_SFTP 2 140#define SUBSYSTEM_INT_SFTP_ERROR 3 141 142login_cap_t *lc; 143 144static int is_child = 0; 145 146/* Name and directory of socket for authentication agent forwarding. */ 147static char *auth_sock_name = NULL; 148static char *auth_sock_dir = NULL; 149 150/* removes the agent forwarding socket */ 151 152static void 153auth_sock_cleanup_proc(struct passwd *pw) 154{ 155 if (auth_sock_name != NULL) { 156 temporarily_use_uid(pw); 157 unlink(auth_sock_name); 158 rmdir(auth_sock_dir); 159 auth_sock_name = NULL; 160 restore_uid(); 161 } 162} 163 164static int 165auth_input_request_forwarding(struct passwd * pw) 166{ 167 Channel *nc; 168 int sock = -1; 169 170 if (auth_sock_name != NULL) { 171 error("authentication forwarding requested twice."); 172 return 0; 173 } 174 175 /* Temporarily drop privileged uid for mkdir/bind. */ 176 temporarily_use_uid(pw); 177 178 /* Allocate a buffer for the socket name, and format the name. */ 179 auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX"); 180 181 /* Create private directory for socket */ 182 if (mkdtemp(auth_sock_dir) == NULL) { 183 packet_send_debug("Agent forwarding disabled: " 184 "mkdtemp() failed: %.100s", strerror(errno)); 185 restore_uid(); 186 free(auth_sock_dir); 187 auth_sock_dir = NULL; 188 goto authsock_err; 189 } 190 191 xasprintf(&auth_sock_name, "%s/agent.%ld", 192 auth_sock_dir, (long) getpid()); 193 194 /* Start a Unix listener on auth_sock_name. */ 195 sock = unix_listener(auth_sock_name, SSH_LISTEN_BACKLOG, 0); 196 197 /* Restore the privileged uid. */ 198 restore_uid(); 199 200 /* Check for socket/bind/listen failure. */ 201 if (sock < 0) 202 goto authsock_err; 203 204 /* Allocate a channel for the authentication agent socket. */ 205 nc = channel_new("auth socket", 206 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1, 207 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 208 0, "auth socket", 1); 209 nc->path = xstrdup(auth_sock_name); 210 return 1; 211 212 authsock_err: 213 free(auth_sock_name); 214 if (auth_sock_dir != NULL) { 215 rmdir(auth_sock_dir); 216 free(auth_sock_dir); 217 } 218 if (sock != -1) 219 close(sock); 220 auth_sock_name = NULL; 221 auth_sock_dir = NULL; 222 return 0; 223} 224 225static void 226display_loginmsg(void) 227{ 228 if (buffer_len(&loginmsg) > 0) { 229 buffer_append(&loginmsg, "\0", 1); 230 printf("%s", (char *)buffer_ptr(&loginmsg)); 231 buffer_clear(&loginmsg); 232 } 233} 234 235void 236do_authenticated(Authctxt *authctxt) 237{ 238 setproctitle("%s", authctxt->pw->pw_name); 239 240 /* setup the channel layer */ 241 /* XXX - streamlocal? */ 242 if (no_port_forwarding_flag || 243 (options.allow_tcp_forwarding & FORWARD_LOCAL) == 0) 244 channel_disable_adm_local_opens(); 245 else 246 channel_permit_all_opens(); 247 248 auth_debug_send(); 249 250 if (compat20) 251 do_authenticated2(authctxt); 252 else 253 do_authenticated1(authctxt); 254 255 do_cleanup(authctxt); 256} 257 258/* 259 * Prepares for an interactive session. This is called after the user has 260 * been successfully authenticated. During this message exchange, pseudo 261 * terminals are allocated, X11, TCP/IP, and authentication agent forwardings 262 * are requested, etc. 263 */ 264static void 265do_authenticated1(Authctxt *authctxt) 266{ 267 Session *s; 268 char *command; 269 int success, type, screen_flag; 270 int enable_compression_after_reply = 0; 271 u_int proto_len, data_len, dlen, compression_level = 0; 272 273 s = session_new(); 274 if (s == NULL) { 275 error("no more sessions"); 276 return; 277 } 278 s->authctxt = authctxt; 279 s->pw = authctxt->pw; 280 281 /* 282 * We stay in this loop until the client requests to execute a shell 283 * or a command. 284 */ 285 for (;;) { 286 success = 0; 287 288 /* Get a packet from the client. */ 289 type = packet_read(); 290 291 /* Process the packet. */ 292 switch (type) { 293 case SSH_CMSG_REQUEST_COMPRESSION: 294 compression_level = packet_get_int(); 295 packet_check_eom(); 296 if (compression_level < 1 || compression_level > 9) { 297 packet_send_debug("Received invalid compression level %d.", 298 compression_level); 299 break; 300 } 301 if (options.compression == COMP_NONE) { 302 debug2("compression disabled"); 303 break; 304 } 305 /* Enable compression after we have responded with SUCCESS. */ 306 enable_compression_after_reply = 1; 307 success = 1; 308 break; 309 310 case SSH_CMSG_REQUEST_PTY: 311 success = session_pty_req(s); 312 break; 313 314 case SSH_CMSG_X11_REQUEST_FORWARDING: 315 s->auth_proto = packet_get_string(&proto_len); 316 s->auth_data = packet_get_string(&data_len); 317 318 screen_flag = packet_get_protocol_flags() & 319 SSH_PROTOFLAG_SCREEN_NUMBER; 320 debug2("SSH_PROTOFLAG_SCREEN_NUMBER: %d", screen_flag); 321 322 if (packet_remaining() == 4) { 323 if (!screen_flag) 324 debug2("Buggy client: " 325 "X11 screen flag missing"); 326 s->screen = packet_get_int(); 327 } else { 328 s->screen = 0; 329 } 330 packet_check_eom(); 331 success = session_setup_x11fwd(s); 332 if (!success) { 333 free(s->auth_proto); 334 free(s->auth_data); 335 s->auth_proto = NULL; 336 s->auth_data = NULL; 337 } 338 break; 339 340 case SSH_CMSG_AGENT_REQUEST_FORWARDING: 341 if (!options.allow_agent_forwarding || 342 no_agent_forwarding_flag || compat13) { 343 debug("Authentication agent forwarding not permitted for this authentication."); 344 break; 345 } 346 debug("Received authentication agent forwarding request."); 347 success = auth_input_request_forwarding(s->pw); 348 break; 349 350 case SSH_CMSG_PORT_FORWARD_REQUEST: 351 if (no_port_forwarding_flag) { 352 debug("Port forwarding not permitted for this authentication."); 353 break; 354 } 355 if (!(options.allow_tcp_forwarding & FORWARD_REMOTE)) { 356 debug("Port forwarding not permitted."); 357 break; 358 } 359 debug("Received TCP/IP port forwarding request."); 360 if (channel_input_port_forward_request(s->pw->pw_uid == 0, 361 &options.fwd_opts) < 0) { 362 debug("Port forwarding failed."); 363 break; 364 } 365 success = 1; 366 break; 367 368 case SSH_CMSG_MAX_PACKET_SIZE: 369 if (packet_set_maxsize(packet_get_int()) > 0) 370 success = 1; 371 break; 372 373 case SSH_CMSG_EXEC_SHELL: 374 case SSH_CMSG_EXEC_CMD: 375 if (type == SSH_CMSG_EXEC_CMD) { 376 command = packet_get_string(&dlen); 377 debug("Exec command '%.500s'", command); 378 if (do_exec(s, command) != 0) 379 packet_disconnect( 380 "command execution failed"); 381 free(command); 382 } else { 383 if (do_exec(s, NULL) != 0) 384 packet_disconnect( 385 "shell execution failed"); 386 } 387 packet_check_eom(); 388 session_close(s); 389 return; 390 391 default: 392 /* 393 * Any unknown messages in this phase are ignored, 394 * and a failure message is returned. 395 */ 396 logit("Unknown packet type received after authentication: %d", type); 397 } 398 packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE); 399 packet_send(); 400 packet_write_wait(); 401 402 /* Enable compression now that we have replied if appropriate. */ 403 if (enable_compression_after_reply) { 404 enable_compression_after_reply = 0; 405 packet_start_compression(compression_level); 406 } 407 } 408} 409 410#define USE_PIPES 1 411/* 412 * This is called to fork and execute a command when we have no tty. This 413 * will call do_child from the child, and server_loop from the parent after 414 * setting up file descriptors and such. 415 */ 416int 417do_exec_no_pty(Session *s, const char *command) 418{ 419 pid_t pid; 420#ifdef USE_PIPES 421 int pin[2], pout[2], perr[2]; 422 423 if (s == NULL) 424 fatal("do_exec_no_pty: no session"); 425 426 /* Allocate pipes for communicating with the program. */ 427 if (pipe(pin) < 0) { 428 error("%s: pipe in: %.100s", __func__, strerror(errno)); 429 return -1; 430 } 431 if (pipe(pout) < 0) { 432 error("%s: pipe out: %.100s", __func__, strerror(errno)); 433 close(pin[0]); 434 close(pin[1]); 435 return -1; 436 } 437 if (pipe(perr) < 0) { 438 error("%s: pipe err: %.100s", __func__, 439 strerror(errno)); 440 close(pin[0]); 441 close(pin[1]); 442 close(pout[0]); 443 close(pout[1]); 444 return -1; 445 } 446#else 447 int inout[2], err[2]; 448 449 if (s == NULL) 450 fatal("do_exec_no_pty: no session"); 451 452 /* Uses socket pairs to communicate with the program. */ 453 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) { 454 error("%s: socketpair #1: %.100s", __func__, strerror(errno)); 455 return -1; 456 } 457 if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) { 458 error("%s: socketpair #2: %.100s", __func__, 459 strerror(errno)); 460 close(inout[0]); 461 close(inout[1]); 462 return -1; 463 } 464#endif 465 466 session_proctitle(s); 467 468 /* Fork the child. */ 469 switch ((pid = fork())) { 470 case -1: 471 error("%s: fork: %.100s", __func__, strerror(errno)); 472#ifdef USE_PIPES 473 close(pin[0]); 474 close(pin[1]); 475 close(pout[0]); 476 close(pout[1]); 477 close(perr[0]); 478 close(perr[1]); 479#else 480 close(inout[0]); 481 close(inout[1]); 482 close(err[0]); 483 close(err[1]); 484#endif 485 return -1; 486 case 0: 487 is_child = 1; 488 489 /* Child. Reinitialize the log since the pid has changed. */ 490 log_init(__progname, options.log_level, 491 options.log_facility, log_stderr); 492 493 /* 494 * Create a new session and process group since the 4.4BSD 495 * setlogin() affects the entire process group. 496 */ 497 if (setsid() < 0) 498 error("setsid failed: %.100s", strerror(errno)); 499 500#ifdef USE_PIPES 501 /* 502 * Redirect stdin. We close the parent side of the socket 503 * pair, and make the child side the standard input. 504 */ 505 close(pin[1]); 506 if (dup2(pin[0], 0) < 0) 507 perror("dup2 stdin"); 508 close(pin[0]); 509 510 /* Redirect stdout. */ 511 close(pout[0]); 512 if (dup2(pout[1], 1) < 0) 513 perror("dup2 stdout"); 514 close(pout[1]); 515 516 /* Redirect stderr. */ 517 close(perr[0]); 518 if (dup2(perr[1], 2) < 0) 519 perror("dup2 stderr"); 520 close(perr[1]); 521#else 522 /* 523 * Redirect stdin, stdout, and stderr. Stdin and stdout will 524 * use the same socket, as some programs (particularly rdist) 525 * seem to depend on it. 526 */ 527 close(inout[1]); 528 close(err[1]); 529 if (dup2(inout[0], 0) < 0) /* stdin */ 530 perror("dup2 stdin"); 531 if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */ 532 perror("dup2 stdout"); 533 close(inout[0]); 534 if (dup2(err[0], 2) < 0) /* stderr */ 535 perror("dup2 stderr"); 536 close(err[0]); 537#endif 538 539 /* Do processing for the child (exec command etc). */ 540 do_child(s, command); 541 /* NOTREACHED */ 542 default: 543 break; 544 } 545 546 s->pid = pid; 547 /* Set interactive/non-interactive mode. */ 548 packet_set_interactive(s->display != NULL, 549 options.ip_qos_interactive, options.ip_qos_bulk); 550 551#ifdef USE_PIPES 552 /* We are the parent. Close the child sides of the pipes. */ 553 close(pin[0]); 554 close(pout[1]); 555 close(perr[1]); 556 557 if (compat20) { 558 session_set_fds(s, pin[1], pout[0], perr[0], 559 s->is_subsystem, 0); 560 } else { 561 /* Enter the interactive session. */ 562 server_loop(pid, pin[1], pout[0], perr[0]); 563 /* server_loop has closed pin[1], pout[0], and perr[0]. */ 564 } 565#else 566 /* We are the parent. Close the child sides of the socket pairs. */ 567 close(inout[0]); 568 close(err[0]); 569 570 /* 571 * Enter the interactive session. Note: server_loop must be able to 572 * handle the case that fdin and fdout are the same. 573 */ 574 if (compat20) { 575 session_set_fds(s, inout[1], inout[1], err[1], 576 s->is_subsystem, 0); 577 } else { 578 server_loop(pid, inout[1], inout[1], err[1]); 579 /* server_loop has closed inout[1] and err[1]. */ 580 } 581#endif 582 return 0; 583} 584 585/* 586 * This is called to fork and execute a command when we have a tty. This 587 * will call do_child from the child, and server_loop from the parent after 588 * setting up file descriptors, controlling tty, updating wtmp, utmp, 589 * lastlog, and other such operations. 590 */ 591int 592do_exec_pty(Session *s, const char *command) 593{ 594 int fdout, ptyfd, ttyfd, ptymaster; 595 pid_t pid; 596 597 if (s == NULL) 598 fatal("do_exec_pty: no session"); 599 ptyfd = s->ptyfd; 600 ttyfd = s->ttyfd; 601 602 /* 603 * Create another descriptor of the pty master side for use as the 604 * standard input. We could use the original descriptor, but this 605 * simplifies code in server_loop. The descriptor is bidirectional. 606 * Do this before forking (and cleanup in the child) so as to 607 * detect and gracefully fail out-of-fd conditions. 608 */ 609 if ((fdout = dup(ptyfd)) < 0) { 610 error("%s: dup #1: %s", __func__, strerror(errno)); 611 close(ttyfd); 612 close(ptyfd); 613 return -1; 614 } 615 /* we keep a reference to the pty master */ 616 if ((ptymaster = dup(ptyfd)) < 0) { 617 error("%s: dup #2: %s", __func__, strerror(errno)); 618 close(ttyfd); 619 close(ptyfd); 620 close(fdout); 621 return -1; 622 } 623 624 /* Fork the child. */ 625 switch ((pid = fork())) { 626 case -1: 627 error("%s: fork: %.100s", __func__, strerror(errno)); 628 close(fdout); 629 close(ptymaster); 630 close(ttyfd); 631 close(ptyfd); 632 return -1; 633 case 0: 634 is_child = 1; 635 636 close(fdout); 637 close(ptymaster); 638 639 /* Child. Reinitialize the log because the pid has changed. */ 640 log_init(__progname, options.log_level, 641 options.log_facility, log_stderr); 642 /* Close the master side of the pseudo tty. */ 643 close(ptyfd); 644 645 /* Make the pseudo tty our controlling tty. */ 646 pty_make_controlling_tty(&ttyfd, s->tty); 647 648 /* Redirect stdin/stdout/stderr from the pseudo tty. */ 649 if (dup2(ttyfd, 0) < 0) 650 error("dup2 stdin: %s", strerror(errno)); 651 if (dup2(ttyfd, 1) < 0) 652 error("dup2 stdout: %s", strerror(errno)); 653 if (dup2(ttyfd, 2) < 0) 654 error("dup2 stderr: %s", strerror(errno)); 655 656 /* Close the extra descriptor for the pseudo tty. */ 657 close(ttyfd); 658 659 /* record login, etc. similar to login(1) */ 660 if (!(options.use_login && command == NULL)) 661 do_login(s, command); 662 663 /* 664 * Do common processing for the child, such as execing 665 * the command. 666 */ 667 do_child(s, command); 668 /* NOTREACHED */ 669 default: 670 break; 671 } 672 s->pid = pid; 673 674 /* Parent. Close the slave side of the pseudo tty. */ 675 close(ttyfd); 676 677 /* Enter interactive session. */ 678 s->ptymaster = ptymaster; 679 packet_set_interactive(1, 680 options.ip_qos_interactive, options.ip_qos_bulk); 681 if (compat20) { 682 session_set_fds(s, ptyfd, fdout, -1, 1, 1); 683 } else { 684 server_loop(pid, ptyfd, fdout, -1); 685 /* server_loop _has_ closed ptyfd and fdout. */ 686 } 687 return 0; 688} 689 690/* 691 * This is called to fork and execute a command. If another command is 692 * to be forced, execute that instead. 693 */ 694int 695do_exec(Session *s, const char *command) 696{ 697 int ret; 698 const char *forced = NULL; 699 char session_type[1024], *tty = NULL; 700 701 if (options.adm_forced_command) { 702 original_command = command; 703 command = options.adm_forced_command; 704 forced = "(config)"; 705 } else if (forced_command) { 706 original_command = command; 707 command = forced_command; 708 forced = "(key-option)"; 709 } 710 if (forced != NULL) { 711 if (IS_INTERNAL_SFTP(command)) { 712 s->is_subsystem = s->is_subsystem ? 713 SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR; 714 } else if (s->is_subsystem) 715 s->is_subsystem = SUBSYSTEM_EXT; 716 snprintf(session_type, sizeof(session_type), 717 "forced-command %s '%.900s'", forced, command); 718 } else if (s->is_subsystem) { 719 snprintf(session_type, sizeof(session_type), 720 "subsystem '%.900s'", s->subsys); 721 } else if (command == NULL) { 722 snprintf(session_type, sizeof(session_type), "shell"); 723 } else { 724 /* NB. we don't log unforced commands to preserve privacy */ 725 snprintf(session_type, sizeof(session_type), "command"); 726 } 727 728 if (s->ttyfd != -1) { 729 tty = s->tty; 730 if (strncmp(tty, "/dev/", 5) == 0) 731 tty += 5; 732 } 733 734 verbose("Starting session: %s%s%s for %s from %.200s port %d", 735 session_type, 736 tty == NULL ? "" : " on ", 737 tty == NULL ? "" : tty, 738 s->pw->pw_name, 739 get_remote_ipaddr(), 740 get_remote_port()); 741 742#ifdef GSSAPI 743 if (options.gss_authentication) { 744 temporarily_use_uid(s->pw); 745 ssh_gssapi_storecreds(); 746 restore_uid(); 747 } 748#endif 749 if (s->ttyfd != -1) 750 ret = do_exec_pty(s, command); 751 else 752 ret = do_exec_no_pty(s, command); 753 754 original_command = NULL; 755 756 /* 757 * Clear loginmsg: it's the child's responsibility to display 758 * it to the user, otherwise multiple sessions may accumulate 759 * multiple copies of the login messages. 760 */ 761 buffer_clear(&loginmsg); 762 763 return ret; 764} 765 766 767/* administrative, login(1)-like work */ 768void 769do_login(Session *s, const char *command) 770{ 771 socklen_t fromlen; 772 struct sockaddr_storage from; 773 struct passwd * pw = s->pw; 774 pid_t pid = getpid(); 775 776 /* 777 * Get IP address of client. If the connection is not a socket, let 778 * the address be 0.0.0.0. 779 */ 780 memset(&from, 0, sizeof(from)); 781 fromlen = sizeof(from); 782 if (packet_connection_is_on_socket()) { 783 if (getpeername(packet_get_connection_in(), 784 (struct sockaddr *)&from, &fromlen) < 0) { 785 debug("getpeername: %.100s", strerror(errno)); 786 cleanup_exit(255); 787 } 788 } 789 790 /* Record that there was a login on that tty from the remote host. */ 791 if (!use_privsep) 792 record_login(pid, s->tty, pw->pw_name, pw->pw_uid, 793 get_remote_name_or_ip(utmp_len, 794 options.use_dns), 795 (struct sockaddr *)&from, fromlen); 796 797 if (check_quietlogin(s, command)) 798 return; 799 800 display_loginmsg(); 801 802 do_motd(); 803} 804 805/* 806 * Display the message of the day. 807 */ 808void 809do_motd(void) 810{ 811 FILE *f; 812 char buf[256]; 813 814 if (options.print_motd) { 815 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd", 816 "/etc/motd"), "r"); 817 if (f) { 818 while (fgets(buf, sizeof(buf), f)) 819 fputs(buf, stdout); 820 fclose(f); 821 } 822 } 823} 824 825 826/* 827 * Check for quiet login, either .hushlogin or command given. 828 */ 829int 830check_quietlogin(Session *s, const char *command) 831{ 832 char buf[256]; 833 struct passwd *pw = s->pw; 834 struct stat st; 835 836 /* Return 1 if .hushlogin exists or a command given. */ 837 if (command != NULL) 838 return 1; 839 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir); 840 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0) 841 return 1; 842 return 0; 843} 844 845/* 846 * Sets the value of the given variable in the environment. If the variable 847 * already exists, its value is overridden. 848 */ 849void 850child_set_env(char ***envp, u_int *envsizep, const char *name, 851 const char *value) 852{ 853 char **env; 854 u_int envsize; 855 u_int i, namelen; 856 857 if (strchr(name, '=') != NULL) { 858 error("Invalid environment variable \"%.100s\"", name); 859 return; 860 } 861 862 /* 863 * Find the slot where the value should be stored. If the variable 864 * already exists, we reuse the slot; otherwise we append a new slot 865 * at the end of the array, expanding if necessary. 866 */ 867 env = *envp; 868 namelen = strlen(name); 869 for (i = 0; env[i]; i++) 870 if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=') 871 break; 872 if (env[i]) { 873 /* Reuse the slot. */ 874 free(env[i]); 875 } else { 876 /* New variable. Expand if necessary. */ 877 envsize = *envsizep; 878 if (i >= envsize - 1) { 879 if (envsize >= 1000) 880 fatal("child_set_env: too many env vars"); 881 envsize += 50; 882 env = (*envp) = xrealloc(env, envsize, sizeof(char *)); 883 *envsizep = envsize; 884 } 885 /* Need to set the NULL pointer at end of array beyond the new slot. */ 886 env[i + 1] = NULL; 887 } 888 889 /* Allocate space and format the variable in the appropriate slot. */ 890 env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1); 891 snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value); 892} 893 894/* 895 * Reads environment variables from the given file and adds/overrides them 896 * into the environment. If the file does not exist, this does nothing. 897 * Otherwise, it must consist of empty lines, comments (line starts with '#') 898 * and assignments of the form name=value. No other forms are allowed. 899 */ 900static void 901read_environment_file(char ***env, u_int *envsize, 902 const char *filename) 903{ 904 FILE *f; 905 char buf[4096]; 906 char *cp, *value; 907 u_int lineno = 0; 908 909 f = fopen(filename, "r"); 910 if (!f) 911 return; 912 913 while (fgets(buf, sizeof(buf), f)) { 914 if (++lineno > 1000) 915 fatal("Too many lines in environment file %s", filename); 916 for (cp = buf; *cp == ' ' || *cp == '\t'; cp++) 917 ; 918 if (!*cp || *cp == '#' || *cp == '\n') 919 continue; 920 921 cp[strcspn(cp, "\n")] = '\0'; 922 923 value = strchr(cp, '='); 924 if (value == NULL) { 925 fprintf(stderr, "Bad line %u in %.100s\n", lineno, 926 filename); 927 continue; 928 } 929 /* 930 * Replace the equals sign by nul, and advance value to 931 * the value string. 932 */ 933 *value = '\0'; 934 value++; 935 child_set_env(env, envsize, cp, value); 936 } 937 fclose(f); 938} 939 940static char ** 941do_setup_env(Session *s, const char *shell) 942{ 943 char buf[256]; 944 u_int i, envsize; 945 char **env, *laddr; 946 struct passwd *pw = s->pw; 947 948 /* Initialize the environment. */ 949 envsize = 100; 950 env = xcalloc(envsize, sizeof(char *)); 951 env[0] = NULL; 952 953#ifdef GSSAPI 954 /* Allow any GSSAPI methods that we've used to alter 955 * the childs environment as they see fit 956 */ 957 ssh_gssapi_do_child(&env, &envsize); 958#endif 959 960 if (!options.use_login) { 961 /* Set basic environment. */ 962 for (i = 0; i < s->num_env; i++) 963 child_set_env(&env, &envsize, s->env[i].name, 964 s->env[i].val); 965 966 child_set_env(&env, &envsize, "USER", pw->pw_name); 967 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name); 968 child_set_env(&env, &envsize, "HOME", pw->pw_dir); 969 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0) 970 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH); 971 else 972 child_set_env(&env, &envsize, "PATH", getenv("PATH")); 973 974 snprintf(buf, sizeof buf, "%.200s/%.50s", 975 _PATH_MAILDIR, pw->pw_name); 976 child_set_env(&env, &envsize, "MAIL", buf); 977 978 /* Normal systems set SHELL by default. */ 979 child_set_env(&env, &envsize, "SHELL", shell); 980 } 981 if (getenv("TZ")) 982 child_set_env(&env, &envsize, "TZ", getenv("TZ")); 983 984 /* Set custom environment options from RSA authentication. */ 985 if (!options.use_login) { 986 while (custom_environment) { 987 struct envstring *ce = custom_environment; 988 char *str = ce->s; 989 990 for (i = 0; str[i] != '=' && str[i]; i++) 991 ; 992 if (str[i] == '=') { 993 str[i] = 0; 994 child_set_env(&env, &envsize, str, str + i + 1); 995 } 996 custom_environment = ce->next; 997 free(ce->s); 998 free(ce); 999 } 1000 } 1001 1002 /* SSH_CLIENT deprecated */ 1003 snprintf(buf, sizeof buf, "%.50s %d %d", 1004 get_remote_ipaddr(), get_remote_port(), get_local_port()); 1005 child_set_env(&env, &envsize, "SSH_CLIENT", buf); 1006 1007 laddr = get_local_ipaddr(packet_get_connection_in()); 1008 snprintf(buf, sizeof buf, "%.50s %d %.50s %d", 1009 get_remote_ipaddr(), get_remote_port(), laddr, get_local_port()); 1010 free(laddr); 1011 child_set_env(&env, &envsize, "SSH_CONNECTION", buf); 1012 1013 if (s->ttyfd != -1) 1014 child_set_env(&env, &envsize, "SSH_TTY", s->tty); 1015 if (s->term) 1016 child_set_env(&env, &envsize, "TERM", s->term); 1017 if (s->display) 1018 child_set_env(&env, &envsize, "DISPLAY", s->display); 1019 if (original_command) 1020 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND", 1021 original_command); 1022#ifdef KRB5 1023 if (s->authctxt->krb5_ticket_file) 1024 child_set_env(&env, &envsize, "KRB5CCNAME", 1025 s->authctxt->krb5_ticket_file); 1026#endif 1027 if (auth_sock_name != NULL) 1028 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME, 1029 auth_sock_name); 1030 1031 /* read $HOME/.ssh/environment. */ 1032 if (options.permit_user_env && !options.use_login) { 1033 snprintf(buf, sizeof buf, "%.200s/.ssh/environment", 1034 pw->pw_dir); 1035 read_environment_file(&env, &envsize, buf); 1036 } 1037 if (debug_flag) { 1038 /* dump the environment */ 1039 fprintf(stderr, "Environment:\n"); 1040 for (i = 0; env[i]; i++) 1041 fprintf(stderr, " %.200s\n", env[i]); 1042 } 1043 return env; 1044} 1045 1046/* 1047 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found 1048 * first in this order). 1049 */ 1050static void 1051do_rc_files(Session *s, const char *shell) 1052{ 1053 FILE *f = NULL; 1054 char cmd[1024]; 1055 int do_xauth; 1056 struct stat st; 1057 1058 do_xauth = 1059 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL; 1060 1061 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */ 1062 if (!s->is_subsystem && options.adm_forced_command == NULL && 1063 !no_user_rc && options.permit_user_rc && 1064 stat(_PATH_SSH_USER_RC, &st) >= 0) { 1065 snprintf(cmd, sizeof cmd, "%s -c '%s %s'", 1066 shell, _PATH_BSHELL, _PATH_SSH_USER_RC); 1067 if (debug_flag) 1068 fprintf(stderr, "Running %s\n", cmd); 1069 f = popen(cmd, "w"); 1070 if (f) { 1071 if (do_xauth) 1072 fprintf(f, "%s %s\n", s->auth_proto, 1073 s->auth_data); 1074 pclose(f); 1075 } else 1076 fprintf(stderr, "Could not run %s\n", 1077 _PATH_SSH_USER_RC); 1078 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) { 1079 if (debug_flag) 1080 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL, 1081 _PATH_SSH_SYSTEM_RC); 1082 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w"); 1083 if (f) { 1084 if (do_xauth) 1085 fprintf(f, "%s %s\n", s->auth_proto, 1086 s->auth_data); 1087 pclose(f); 1088 } else 1089 fprintf(stderr, "Could not run %s\n", 1090 _PATH_SSH_SYSTEM_RC); 1091 } else if (do_xauth && options.xauth_location != NULL) { 1092 /* Add authority data to .Xauthority if appropriate. */ 1093 if (debug_flag) { 1094 fprintf(stderr, 1095 "Running %.500s remove %.100s\n", 1096 options.xauth_location, s->auth_display); 1097 fprintf(stderr, 1098 "%.500s add %.100s %.100s %.100s\n", 1099 options.xauth_location, s->auth_display, 1100 s->auth_proto, s->auth_data); 1101 } 1102 snprintf(cmd, sizeof cmd, "%s -q -", 1103 options.xauth_location); 1104 f = popen(cmd, "w"); 1105 if (f) { 1106 fprintf(f, "remove %s\n", 1107 s->auth_display); 1108 fprintf(f, "add %s %s %s\n", 1109 s->auth_display, s->auth_proto, 1110 s->auth_data); 1111 pclose(f); 1112 } else { 1113 fprintf(stderr, "Could not run %s\n", 1114 cmd); 1115 } 1116 } 1117} 1118 1119static void 1120do_nologin(struct passwd *pw) 1121{ 1122 FILE *f = NULL; 1123 char buf[1024], *nl, *def_nl = _PATH_NOLOGIN; 1124 struct stat sb; 1125 1126 if (login_getcapbool(lc, "ignorenologin", 0) || pw->pw_uid == 0) 1127 return; 1128 nl = login_getcapstr(lc, "nologin", def_nl, def_nl); 1129 1130 if (stat(nl, &sb) == -1) { 1131 if (nl != def_nl) 1132 free(nl); 1133 return; 1134 } 1135 1136 /* /etc/nologin exists. Print its contents if we can and exit. */ 1137 logit("User %.100s not allowed because %s exists", pw->pw_name, nl); 1138 if ((f = fopen(nl, "r")) != NULL) { 1139 while (fgets(buf, sizeof(buf), f)) 1140 fputs(buf, stderr); 1141 fclose(f); 1142 } 1143 exit(254); 1144} 1145 1146/* 1147 * Chroot into a directory after checking it for safety: all path components 1148 * must be root-owned directories with strict permissions. 1149 */ 1150static void 1151safely_chroot(const char *path, uid_t uid) 1152{ 1153 const char *cp; 1154 char component[PATH_MAX]; 1155 struct stat st; 1156 1157 if (*path != '/') 1158 fatal("chroot path does not begin at root"); 1159 if (strlen(path) >= sizeof(component)) 1160 fatal("chroot path too long"); 1161 1162 /* 1163 * Descend the path, checking that each component is a 1164 * root-owned directory with strict permissions. 1165 */ 1166 for (cp = path; cp != NULL;) { 1167 if ((cp = strchr(cp, '/')) == NULL) 1168 strlcpy(component, path, sizeof(component)); 1169 else { 1170 cp++; 1171 memcpy(component, path, cp - path); 1172 component[cp - path] = '\0'; 1173 } 1174 1175 debug3("%s: checking '%s'", __func__, component); 1176 1177 if (stat(component, &st) != 0) 1178 fatal("%s: stat(\"%s\"): %s", __func__, 1179 component, strerror(errno)); 1180 if (st.st_uid != 0 || (st.st_mode & 022) != 0) 1181 fatal("bad ownership or modes for chroot " 1182 "directory %s\"%s\"", 1183 cp == NULL ? "" : "component ", component); 1184 if (!S_ISDIR(st.st_mode)) 1185 fatal("chroot path %s\"%s\" is not a directory", 1186 cp == NULL ? "" : "component ", component); 1187 1188 } 1189 1190 if (chdir(path) == -1) 1191 fatal("Unable to chdir to chroot path \"%s\": " 1192 "%s", path, strerror(errno)); 1193 if (chroot(path) == -1) 1194 fatal("chroot(\"%s\"): %s", path, strerror(errno)); 1195 if (chdir("/") == -1) 1196 fatal("%s: chdir(/) after chroot: %s", 1197 __func__, strerror(errno)); 1198 verbose("Changed root directory to \"%s\"", path); 1199} 1200 1201/* Set login name, uid, gid, and groups. */ 1202void 1203do_setusercontext(struct passwd *pw) 1204{ 1205 char *chroot_path, *tmp; 1206 1207 if (getuid() == 0 || geteuid() == 0) { 1208 /* Prepare groups */ 1209 if (setusercontext(lc, pw, pw->pw_uid, 1210 (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) { 1211 perror("unable to set user context"); 1212 exit(1); 1213 } 1214 1215 if (options.chroot_directory != NULL && 1216 strcasecmp(options.chroot_directory, "none") != 0) { 1217 tmp = tilde_expand_filename(options.chroot_directory, 1218 pw->pw_uid); 1219 chroot_path = percent_expand(tmp, "h", pw->pw_dir, 1220 "u", pw->pw_name, (char *)NULL); 1221 safely_chroot(chroot_path, pw->pw_uid); 1222 free(tmp); 1223 free(chroot_path); 1224 /* Make sure we don't attempt to chroot again */ 1225 free(options.chroot_directory); 1226 options.chroot_directory = NULL; 1227 } 1228 1229 /* Set UID */ 1230 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) { 1231 perror("unable to set user context (setuser)"); 1232 exit(1); 1233 } 1234 } else if (options.chroot_directory != NULL && 1235 strcasecmp(options.chroot_directory, "none") != 0) { 1236 fatal("server lacks privileges to chroot to ChrootDirectory"); 1237 } 1238 1239 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid) 1240 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid); 1241} 1242 1243static void 1244do_pwchange(Session *s) 1245{ 1246 fflush(NULL); 1247 fprintf(stderr, "WARNING: Your password has expired.\n"); 1248 if (s->ttyfd != -1) { 1249 fprintf(stderr, 1250 "You must change your password now and login again!\n"); 1251 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL); 1252 perror("passwd"); 1253 } else { 1254 fprintf(stderr, 1255 "Password change required but no TTY available.\n"); 1256 } 1257 exit(1); 1258} 1259 1260static void 1261launch_login(struct passwd *pw, const char *hostname) 1262{ 1263 /* Launch login(1). */ 1264 1265 execl("/usr/bin/login", "login", "-h", hostname, 1266 "-p", "-f", "--", pw->pw_name, (char *)NULL); 1267 1268 /* Login couldn't be executed, die. */ 1269 1270 perror("login"); 1271 exit(1); 1272} 1273 1274static void 1275child_close_fds(void) 1276{ 1277 extern int auth_sock; 1278 1279 if (auth_sock != -1) { 1280 close(auth_sock); 1281 auth_sock = -1; 1282 } 1283 1284 if (packet_get_connection_in() == packet_get_connection_out()) 1285 close(packet_get_connection_in()); 1286 else { 1287 close(packet_get_connection_in()); 1288 close(packet_get_connection_out()); 1289 } 1290 /* 1291 * Close all descriptors related to channels. They will still remain 1292 * open in the parent. 1293 */ 1294 /* XXX better use close-on-exec? -markus */ 1295 channel_close_all(); 1296 1297 /* 1298 * Close any extra file descriptors. Note that there may still be 1299 * descriptors left by system functions. They will be closed later. 1300 */ 1301 endpwent(); 1302 1303 /* 1304 * Close any extra open file descriptors so that we don't have them 1305 * hanging around in clients. Note that we want to do this after 1306 * initgroups, because at least on Solaris 2.3 it leaves file 1307 * descriptors open. 1308 */ 1309 closefrom(STDERR_FILENO + 1); 1310} 1311 1312/* 1313 * Performs common processing for the child, such as setting up the 1314 * environment, closing extra file descriptors, setting the user and group 1315 * ids, and executing the command or shell. 1316 */ 1317#define ARGV_MAX 10 1318void 1319do_child(Session *s, const char *command) 1320{ 1321 extern char **environ; 1322 char **env; 1323 char *argv[ARGV_MAX]; 1324 const char *shell, *shell0, *hostname = NULL; 1325 struct passwd *pw = s->pw; 1326 int r = 0; 1327 1328 /* remove hostkey from the child's memory */ 1329 destroy_sensitive_data(); 1330 1331 /* Force a password change */ 1332 if (s->authctxt->force_pwchange) { 1333 do_setusercontext(pw); 1334 child_close_fds(); 1335 do_pwchange(s); 1336 exit(1); 1337 } 1338 1339 /* login(1) is only called if we execute the login shell */ 1340 if (options.use_login && command != NULL) 1341 options.use_login = 0; 1342 1343 /* 1344 * Login(1) does this as well, and it needs uid 0 for the "-h" 1345 * switch, so we let login(1) to this for us. 1346 */ 1347 if (!options.use_login) { 1348 do_nologin(pw); 1349 do_setusercontext(pw); 1350 } 1351 1352 /* 1353 * Get the shell from the password data. An empty shell field is 1354 * legal, and means /bin/sh. 1355 */ 1356 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell; 1357 1358 /* 1359 * Make sure $SHELL points to the shell from the password file, 1360 * even if shell is overridden from login.conf 1361 */ 1362 env = do_setup_env(s, shell); 1363 1364 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell); 1365 1366 /* we have to stash the hostname before we close our socket. */ 1367 if (options.use_login) 1368 hostname = get_remote_name_or_ip(utmp_len, 1369 options.use_dns); 1370 /* 1371 * Close the connection descriptors; note that this is the child, and 1372 * the server will still have the socket open, and it is important 1373 * that we do not shutdown it. Note that the descriptors cannot be 1374 * closed before building the environment, as we call 1375 * get_remote_ipaddr there. 1376 */ 1377 child_close_fds(); 1378 1379 /* 1380 * Must take new environment into use so that .ssh/rc, 1381 * /etc/ssh/sshrc and xauth are run in the proper environment. 1382 */ 1383 environ = env; 1384 1385#ifdef KRB5 1386 /* 1387 * At this point, we check to see if AFS is active and if we have 1388 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see 1389 * if we can (and need to) extend the ticket into an AFS token. If 1390 * we don't do this, we run into potential problems if the user's 1391 * home directory is in AFS and it's not world-readable. 1392 */ 1393 1394 if (options.kerberos_get_afs_token && k_hasafs() && 1395 (s->authctxt->krb5_ctx != NULL)) { 1396 char cell[64]; 1397 1398 debug("Getting AFS token"); 1399 1400 k_setpag(); 1401 1402 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0) 1403 krb5_afslog(s->authctxt->krb5_ctx, 1404 s->authctxt->krb5_fwd_ccache, cell, NULL); 1405 1406 krb5_afslog_home(s->authctxt->krb5_ctx, 1407 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir); 1408 } 1409#endif 1410 1411 /* Change current directory to the user's home directory. */ 1412 if (chdir(pw->pw_dir) < 0) { 1413 /* Suppress missing homedir warning for chroot case */ 1414 r = login_getcapbool(lc, "requirehome", 0); 1415 if (r || options.chroot_directory == NULL || 1416 strcasecmp(options.chroot_directory, "none") == 0) 1417 fprintf(stderr, "Could not chdir to home " 1418 "directory %s: %s\n", pw->pw_dir, 1419 strerror(errno)); 1420 if (r) 1421 exit(1); 1422 } 1423 1424 closefrom(STDERR_FILENO + 1); 1425 1426 if (!options.use_login) 1427 do_rc_files(s, shell); 1428 1429 /* restore SIGPIPE for child */ 1430 signal(SIGPIPE, SIG_DFL); 1431 1432 if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) { 1433 printf("This service allows sftp connections only.\n"); 1434 fflush(NULL); 1435 exit(1); 1436 } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) { 1437 extern int optind, optreset; 1438 int i; 1439 char *p, *args; 1440 1441 setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME); 1442 args = xstrdup(command ? command : "sftp-server"); 1443 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " "))) 1444 if (i < ARGV_MAX - 1) 1445 argv[i++] = p; 1446 argv[i] = NULL; 1447 optind = optreset = 1; 1448 __progname = argv[0]; 1449 exit(sftp_server_main(i, argv, s->pw)); 1450 } 1451 1452 fflush(NULL); 1453 1454 if (options.use_login) { 1455 launch_login(pw, hostname); 1456 /* NEVERREACHED */ 1457 } 1458 1459 /* Get the last component of the shell name. */ 1460 if ((shell0 = strrchr(shell, '/')) != NULL) 1461 shell0++; 1462 else 1463 shell0 = shell; 1464 1465 /* 1466 * If we have no command, execute the shell. In this case, the shell 1467 * name to be passed in argv[0] is preceded by '-' to indicate that 1468 * this is a login shell. 1469 */ 1470 if (!command) { 1471 char argv0[256]; 1472 1473 /* Start the shell. Set initial character to '-'. */ 1474 argv0[0] = '-'; 1475 1476 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1) 1477 >= sizeof(argv0) - 1) { 1478 errno = EINVAL; 1479 perror(shell); 1480 exit(1); 1481 } 1482 1483 /* Execute the shell. */ 1484 argv[0] = argv0; 1485 argv[1] = NULL; 1486 execve(shell, argv, env); 1487 1488 /* Executing the shell failed. */ 1489 perror(shell); 1490 exit(1); 1491 } 1492 /* 1493 * Execute the command using the user's shell. This uses the -c 1494 * option to execute the command. 1495 */ 1496 argv[0] = (char *) shell0; 1497 argv[1] = "-c"; 1498 argv[2] = (char *) command; 1499 argv[3] = NULL; 1500 execve(shell, argv, env); 1501 perror(shell); 1502 exit(1); 1503} 1504 1505void 1506session_unused(int id) 1507{ 1508 debug3("%s: session id %d unused", __func__, id); 1509 if (id >= options.max_sessions || 1510 id >= sessions_nalloc) { 1511 fatal("%s: insane session id %d (max %d nalloc %d)", 1512 __func__, id, options.max_sessions, sessions_nalloc); 1513 } 1514 memset(&sessions[id], 0, sizeof(*sessions)); 1515 sessions[id].self = id; 1516 sessions[id].used = 0; 1517 sessions[id].chanid = -1; 1518 sessions[id].ptyfd = -1; 1519 sessions[id].ttyfd = -1; 1520 sessions[id].ptymaster = -1; 1521 sessions[id].x11_chanids = NULL; 1522 sessions[id].next_unused = sessions_first_unused; 1523 sessions_first_unused = id; 1524} 1525 1526Session * 1527session_new(void) 1528{ 1529 Session *s, *tmp; 1530 1531 if (sessions_first_unused == -1) { 1532 if (sessions_nalloc >= options.max_sessions) 1533 return NULL; 1534 debug2("%s: allocate (allocated %d max %d)", 1535 __func__, sessions_nalloc, options.max_sessions); 1536 tmp = xrealloc(sessions, sessions_nalloc + 1, 1537 sizeof(*sessions)); 1538 if (tmp == NULL) { 1539 error("%s: cannot allocate %d sessions", 1540 __func__, sessions_nalloc + 1); 1541 return NULL; 1542 } 1543 sessions = tmp; 1544 session_unused(sessions_nalloc++); 1545 } 1546 1547 if (sessions_first_unused >= sessions_nalloc || 1548 sessions_first_unused < 0) { 1549 fatal("%s: insane first_unused %d max %d nalloc %d", 1550 __func__, sessions_first_unused, options.max_sessions, 1551 sessions_nalloc); 1552 } 1553 1554 s = &sessions[sessions_first_unused]; 1555 if (s->used) { 1556 fatal("%s: session %d already used", 1557 __func__, sessions_first_unused); 1558 } 1559 sessions_first_unused = s->next_unused; 1560 s->used = 1; 1561 s->next_unused = -1; 1562 debug("session_new: session %d", s->self); 1563 1564 return s; 1565} 1566 1567static void 1568session_dump(void) 1569{ 1570 int i; 1571 for (i = 0; i < sessions_nalloc; i++) { 1572 Session *s = &sessions[i]; 1573 1574 debug("dump: used %d next_unused %d session %d %p " 1575 "channel %d pid %ld", 1576 s->used, 1577 s->next_unused, 1578 s->self, 1579 s, 1580 s->chanid, 1581 (long)s->pid); 1582 } 1583} 1584 1585int 1586session_open(Authctxt *authctxt, int chanid) 1587{ 1588 Session *s = session_new(); 1589 debug("session_open: channel %d", chanid); 1590 if (s == NULL) { 1591 error("no more sessions"); 1592 return 0; 1593 } 1594 s->authctxt = authctxt; 1595 s->pw = authctxt->pw; 1596 if (s->pw == NULL || !authctxt->valid) 1597 fatal("no user for session %d", s->self); 1598 debug("session_open: session %d: link with channel %d", s->self, chanid); 1599 s->chanid = chanid; 1600 return 1; 1601} 1602 1603Session * 1604session_by_tty(char *tty) 1605{ 1606 int i; 1607 for (i = 0; i < sessions_nalloc; i++) { 1608 Session *s = &sessions[i]; 1609 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) { 1610 debug("session_by_tty: session %d tty %s", i, tty); 1611 return s; 1612 } 1613 } 1614 debug("session_by_tty: unknown tty %.100s", tty); 1615 session_dump(); 1616 return NULL; 1617} 1618 1619static Session * 1620session_by_channel(int id) 1621{ 1622 int i; 1623 for (i = 0; i < sessions_nalloc; i++) { 1624 Session *s = &sessions[i]; 1625 if (s->used && s->chanid == id) { 1626 debug("session_by_channel: session %d channel %d", 1627 i, id); 1628 return s; 1629 } 1630 } 1631 debug("session_by_channel: unknown channel %d", id); 1632 session_dump(); 1633 return NULL; 1634} 1635 1636static Session * 1637session_by_x11_channel(int id) 1638{ 1639 int i, j; 1640 1641 for (i = 0; i < sessions_nalloc; i++) { 1642 Session *s = &sessions[i]; 1643 1644 if (s->x11_chanids == NULL || !s->used) 1645 continue; 1646 for (j = 0; s->x11_chanids[j] != -1; j++) { 1647 if (s->x11_chanids[j] == id) { 1648 debug("session_by_x11_channel: session %d " 1649 "channel %d", s->self, id); 1650 return s; 1651 } 1652 } 1653 } 1654 debug("session_by_x11_channel: unknown channel %d", id); 1655 session_dump(); 1656 return NULL; 1657} 1658 1659static Session * 1660session_by_pid(pid_t pid) 1661{ 1662 int i; 1663 debug("session_by_pid: pid %ld", (long)pid); 1664 for (i = 0; i < sessions_nalloc; i++) { 1665 Session *s = &sessions[i]; 1666 if (s->used && s->pid == pid) 1667 return s; 1668 } 1669 error("session_by_pid: unknown pid %ld", (long)pid); 1670 session_dump(); 1671 return NULL; 1672} 1673 1674static int 1675session_window_change_req(Session *s) 1676{ 1677 s->col = packet_get_int(); 1678 s->row = packet_get_int(); 1679 s->xpixel = packet_get_int(); 1680 s->ypixel = packet_get_int(); 1681 packet_check_eom(); 1682 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel); 1683 return 1; 1684} 1685 1686static int 1687session_pty_req(Session *s) 1688{ 1689 u_int len; 1690 int n_bytes; 1691 1692 if (no_pty_flag || !options.permit_tty) { 1693 debug("Allocating a pty not permitted for this authentication."); 1694 return 0; 1695 } 1696 if (s->ttyfd != -1) { 1697 packet_disconnect("Protocol error: you already have a pty."); 1698 return 0; 1699 } 1700 1701 s->term = packet_get_string(&len); 1702 1703 if (compat20) { 1704 s->col = packet_get_int(); 1705 s->row = packet_get_int(); 1706 } else { 1707 s->row = packet_get_int(); 1708 s->col = packet_get_int(); 1709 } 1710 s->xpixel = packet_get_int(); 1711 s->ypixel = packet_get_int(); 1712 1713 if (strcmp(s->term, "") == 0) { 1714 free(s->term); 1715 s->term = NULL; 1716 } 1717 1718 /* Allocate a pty and open it. */ 1719 debug("Allocating pty."); 1720 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, 1721 sizeof(s->tty)))) { 1722 free(s->term); 1723 s->term = NULL; 1724 s->ptyfd = -1; 1725 s->ttyfd = -1; 1726 error("session_pty_req: session %d alloc failed", s->self); 1727 return 0; 1728 } 1729 debug("session_pty_req: session %d alloc %s", s->self, s->tty); 1730 1731 /* for SSH1 the tty modes length is not given */ 1732 if (!compat20) 1733 n_bytes = packet_remaining(); 1734 tty_parse_modes(s->ttyfd, &n_bytes); 1735 1736 if (!use_privsep) 1737 pty_setowner(s->pw, s->tty); 1738 1739 /* Set window size from the packet. */ 1740 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel); 1741 1742 packet_check_eom(); 1743 session_proctitle(s); 1744 return 1; 1745} 1746 1747static int 1748session_subsystem_req(Session *s) 1749{ 1750 struct stat st; 1751 u_int len; 1752 int success = 0; 1753 char *prog, *cmd; 1754 u_int i; 1755 1756 s->subsys = packet_get_string(&len); 1757 packet_check_eom(); 1758 debug2("subsystem request for %.100s by user %s", s->subsys, 1759 s->pw->pw_name); 1760 1761 for (i = 0; i < options.num_subsystems; i++) { 1762 if (strcmp(s->subsys, options.subsystem_name[i]) == 0) { 1763 prog = options.subsystem_command[i]; 1764 cmd = options.subsystem_args[i]; 1765 if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) { 1766 s->is_subsystem = SUBSYSTEM_INT_SFTP; 1767 debug("subsystem: %s", prog); 1768 } else { 1769 if (stat(prog, &st) < 0) 1770 debug("subsystem: cannot stat %s: %s", 1771 prog, strerror(errno)); 1772 s->is_subsystem = SUBSYSTEM_EXT; 1773 debug("subsystem: exec() %s", cmd); 1774 } 1775 success = do_exec(s, cmd) == 0; 1776 break; 1777 } 1778 } 1779 1780 if (!success) 1781 logit("subsystem request for %.100s by user %s failed, " 1782 "subsystem not found", s->subsys, s->pw->pw_name); 1783 1784 return success; 1785} 1786 1787static int 1788session_x11_req(Session *s) 1789{ 1790 int success; 1791 1792 if (s->auth_proto != NULL || s->auth_data != NULL) { 1793 error("session_x11_req: session %d: " 1794 "x11 forwarding already active", s->self); 1795 return 0; 1796 } 1797 s->single_connection = packet_get_char(); 1798 s->auth_proto = packet_get_string(NULL); 1799 s->auth_data = packet_get_string(NULL); 1800 s->screen = packet_get_int(); 1801 packet_check_eom(); 1802 1803 success = session_setup_x11fwd(s); 1804 if (!success) { 1805 free(s->auth_proto); 1806 free(s->auth_data); 1807 s->auth_proto = NULL; 1808 s->auth_data = NULL; 1809 } 1810 return success; 1811} 1812 1813static int 1814session_shell_req(Session *s) 1815{ 1816 packet_check_eom(); 1817 return do_exec(s, NULL) == 0; 1818} 1819 1820static int 1821session_exec_req(Session *s) 1822{ 1823 u_int len, success; 1824 1825 char *command = packet_get_string(&len); 1826 packet_check_eom(); 1827 success = do_exec(s, command) == 0; 1828 free(command); 1829 return success; 1830} 1831 1832static int 1833session_break_req(Session *s) 1834{ 1835 1836 packet_get_int(); /* ignored */ 1837 packet_check_eom(); 1838 1839 if (s->ptymaster == -1 || tcsendbreak(s->ptymaster, 0) < 0) 1840 return 0; 1841 return 1; 1842} 1843 1844static int 1845session_env_req(Session *s) 1846{ 1847 char *name, *val; 1848 u_int name_len, val_len, i; 1849 1850 name = packet_get_cstring(&name_len); 1851 val = packet_get_cstring(&val_len); 1852 packet_check_eom(); 1853 1854 /* Don't set too many environment variables */ 1855 if (s->num_env > 128) { 1856 debug2("Ignoring env request %s: too many env vars", name); 1857 goto fail; 1858 } 1859 1860 for (i = 0; i < options.num_accept_env; i++) { 1861 if (match_pattern(name, options.accept_env[i])) { 1862 debug2("Setting env %d: %s=%s", s->num_env, name, val); 1863 s->env = xrealloc(s->env, s->num_env + 1, 1864 sizeof(*s->env)); 1865 s->env[s->num_env].name = name; 1866 s->env[s->num_env].val = val; 1867 s->num_env++; 1868 return (1); 1869 } 1870 } 1871 debug2("Ignoring env request %s: disallowed name", name); 1872 1873 fail: 1874 free(name); 1875 free(val); 1876 return (0); 1877} 1878 1879static int 1880session_auth_agent_req(Session *s) 1881{ 1882 static int called = 0; 1883 packet_check_eom(); 1884 if (no_agent_forwarding_flag || !options.allow_agent_forwarding) { 1885 debug("session_auth_agent_req: no_agent_forwarding_flag"); 1886 return 0; 1887 } 1888 if (called) { 1889 return 0; 1890 } else { 1891 called = 1; 1892 return auth_input_request_forwarding(s->pw); 1893 } 1894} 1895 1896int 1897session_input_channel_req(Channel *c, const char *rtype) 1898{ 1899 int success = 0; 1900 Session *s; 1901 1902 if ((s = session_by_channel(c->self)) == NULL) { 1903 logit("session_input_channel_req: no session %d req %.100s", 1904 c->self, rtype); 1905 return 0; 1906 } 1907 debug("session_input_channel_req: session %d req %s", s->self, rtype); 1908 1909 /* 1910 * a session is in LARVAL state until a shell, a command 1911 * or a subsystem is executed 1912 */ 1913 if (c->type == SSH_CHANNEL_LARVAL) { 1914 if (strcmp(rtype, "shell") == 0) { 1915 success = session_shell_req(s); 1916 } else if (strcmp(rtype, "exec") == 0) { 1917 success = session_exec_req(s); 1918 } else if (strcmp(rtype, "pty-req") == 0) { 1919 success = session_pty_req(s); 1920 } else if (strcmp(rtype, "x11-req") == 0) { 1921 success = session_x11_req(s); 1922 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) { 1923 success = session_auth_agent_req(s); 1924 } else if (strcmp(rtype, "subsystem") == 0) { 1925 success = session_subsystem_req(s); 1926 } else if (strcmp(rtype, "env") == 0) { 1927 success = session_env_req(s); 1928 } 1929 } 1930 if (strcmp(rtype, "window-change") == 0) { 1931 success = session_window_change_req(s); 1932 } else if (strcmp(rtype, "break") == 0) { 1933 success = session_break_req(s); 1934 } 1935 1936 return success; 1937} 1938 1939void 1940session_set_fds(Session *s, int fdin, int fdout, int fderr, int ignore_fderr, 1941 int is_tty) 1942{ 1943 if (!compat20) 1944 fatal("session_set_fds: called for proto != 2.0"); 1945 /* 1946 * now that have a child and a pipe to the child, 1947 * we can activate our channel and register the fd's 1948 */ 1949 if (s->chanid == -1) 1950 fatal("no channel for session %d", s->self); 1951 channel_set_fds(s->chanid, 1952 fdout, fdin, fderr, 1953 ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ, 1954 1, is_tty, CHAN_SES_WINDOW_DEFAULT); 1955} 1956 1957/* 1958 * Function to perform pty cleanup. Also called if we get aborted abnormally 1959 * (e.g., due to a dropped connection). 1960 */ 1961void 1962session_pty_cleanup2(Session *s) 1963{ 1964 if (s == NULL) { 1965 error("session_pty_cleanup: no session"); 1966 return; 1967 } 1968 if (s->ttyfd == -1) 1969 return; 1970 1971 debug("session_pty_cleanup: session %d release %s", s->self, s->tty); 1972 1973 /* Record that the user has logged out. */ 1974 if (s->pid != 0) 1975 record_logout(s->pid, s->tty); 1976 1977 /* Release the pseudo-tty. */ 1978 if (getuid() == 0) 1979 pty_release(s->tty); 1980 1981 /* 1982 * Close the server side of the socket pairs. We must do this after 1983 * the pty cleanup, so that another process doesn't get this pty 1984 * while we're still cleaning up. 1985 */ 1986 if (s->ptymaster != -1 && close(s->ptymaster) < 0) 1987 error("close(s->ptymaster/%d): %s", 1988 s->ptymaster, strerror(errno)); 1989 1990 /* unlink pty from session */ 1991 s->ttyfd = -1; 1992} 1993 1994void 1995session_pty_cleanup(Session *s) 1996{ 1997 PRIVSEP(session_pty_cleanup2(s)); 1998} 1999 2000static char * 2001sig2name(int sig) 2002{ 2003#define SSH_SIG(x) if (sig == SIG ## x) return #x 2004 SSH_SIG(ABRT); 2005 SSH_SIG(ALRM); 2006 SSH_SIG(FPE); 2007 SSH_SIG(HUP); 2008 SSH_SIG(ILL); 2009 SSH_SIG(INT); 2010 SSH_SIG(KILL); 2011 SSH_SIG(PIPE); 2012 SSH_SIG(QUIT); 2013 SSH_SIG(SEGV); 2014 SSH_SIG(TERM); 2015 SSH_SIG(USR1); 2016 SSH_SIG(USR2); 2017#undef SSH_SIG 2018 return "SIG@openssh.com"; 2019} 2020 2021static void 2022session_close_x11(int id) 2023{ 2024 Channel *c; 2025 2026 if ((c = channel_by_id(id)) == NULL) { 2027 debug("session_close_x11: x11 channel %d missing", id); 2028 } else { 2029 /* Detach X11 listener */ 2030 debug("session_close_x11: detach x11 channel %d", id); 2031 channel_cancel_cleanup(id); 2032 if (c->ostate != CHAN_OUTPUT_CLOSED) 2033 chan_mark_dead(c); 2034 } 2035} 2036 2037static void 2038session_close_single_x11(int id, void *arg) 2039{ 2040 Session *s; 2041 u_int i; 2042 2043 debug3("session_close_single_x11: channel %d", id); 2044 channel_cancel_cleanup(id); 2045 if ((s = session_by_x11_channel(id)) == NULL) 2046 fatal("session_close_single_x11: no x11 channel %d", id); 2047 for (i = 0; s->x11_chanids[i] != -1; i++) { 2048 debug("session_close_single_x11: session %d: " 2049 "closing channel %d", s->self, s->x11_chanids[i]); 2050 /* 2051 * The channel "id" is already closing, but make sure we 2052 * close all of its siblings. 2053 */ 2054 if (s->x11_chanids[i] != id) 2055 session_close_x11(s->x11_chanids[i]); 2056 } 2057 free(s->x11_chanids); 2058 s->x11_chanids = NULL; 2059 free(s->display); 2060 s->display = NULL; 2061 free(s->auth_proto); 2062 s->auth_proto = NULL; 2063 free(s->auth_data); 2064 s->auth_data = NULL; 2065 free(s->auth_display); 2066 s->auth_display = NULL; 2067} 2068 2069static void 2070session_exit_message(Session *s, int status) 2071{ 2072 Channel *c; 2073 2074 if ((c = channel_lookup(s->chanid)) == NULL) 2075 fatal("session_exit_message: session %d: no channel %d", 2076 s->self, s->chanid); 2077 debug("session_exit_message: session %d channel %d pid %ld", 2078 s->self, s->chanid, (long)s->pid); 2079 2080 if (WIFEXITED(status)) { 2081 channel_request_start(s->chanid, "exit-status", 0); 2082 packet_put_int(WEXITSTATUS(status)); 2083 packet_send(); 2084 } else if (WIFSIGNALED(status)) { 2085 channel_request_start(s->chanid, "exit-signal", 0); 2086 packet_put_cstring(sig2name(WTERMSIG(status))); 2087 packet_put_char(WCOREDUMP(status)? 1 : 0); 2088 packet_put_cstring(""); 2089 packet_put_cstring(""); 2090 packet_send(); 2091 } else { 2092 /* Some weird exit cause. Just exit. */ 2093 packet_disconnect("wait returned status %04x.", status); 2094 } 2095 2096 /* disconnect channel */ 2097 debug("session_exit_message: release channel %d", s->chanid); 2098 2099 /* 2100 * Adjust cleanup callback attachment to send close messages when 2101 * the channel gets EOF. The session will be then be closed 2102 * by session_close_by_channel when the childs close their fds. 2103 */ 2104 channel_register_cleanup(c->self, session_close_by_channel, 1); 2105 2106 /* 2107 * emulate a write failure with 'chan_write_failed', nobody will be 2108 * interested in data we write. 2109 * Note that we must not call 'chan_read_failed', since there could 2110 * be some more data waiting in the pipe. 2111 */ 2112 if (c->ostate != CHAN_OUTPUT_CLOSED) 2113 chan_write_failed(c); 2114} 2115 2116void 2117session_close(Session *s) 2118{ 2119 u_int i; 2120 2121 debug("session_close: session %d pid %ld", s->self, (long)s->pid); 2122 if (s->ttyfd != -1) 2123 session_pty_cleanup(s); 2124 free(s->term); 2125 free(s->display); 2126 free(s->x11_chanids); 2127 free(s->auth_display); 2128 free(s->auth_data); 2129 free(s->auth_proto); 2130 free(s->subsys); 2131 if (s->env != NULL) { 2132 for (i = 0; i < s->num_env; i++) { 2133 free(s->env[i].name); 2134 free(s->env[i].val); 2135 } 2136 free(s->env); 2137 } 2138 session_proctitle(s); 2139 session_unused(s->self); 2140} 2141 2142void 2143session_close_by_pid(pid_t pid, int status) 2144{ 2145 Session *s = session_by_pid(pid); 2146 if (s == NULL) { 2147 debug("session_close_by_pid: no session for pid %ld", 2148 (long)pid); 2149 return; 2150 } 2151 if (s->chanid != -1) 2152 session_exit_message(s, status); 2153 if (s->ttyfd != -1) 2154 session_pty_cleanup(s); 2155 s->pid = 0; 2156} 2157 2158/* 2159 * this is called when a channel dies before 2160 * the session 'child' itself dies 2161 */ 2162void 2163session_close_by_channel(int id, void *arg) 2164{ 2165 Session *s = session_by_channel(id); 2166 u_int i; 2167 2168 if (s == NULL) { 2169 debug("session_close_by_channel: no session for id %d", id); 2170 return; 2171 } 2172 debug("session_close_by_channel: channel %d child %ld", 2173 id, (long)s->pid); 2174 if (s->pid != 0) { 2175 debug("session_close_by_channel: channel %d: has child", id); 2176 /* 2177 * delay detach of session, but release pty, since 2178 * the fd's to the child are already closed 2179 */ 2180 if (s->ttyfd != -1) 2181 session_pty_cleanup(s); 2182 return; 2183 } 2184 /* detach by removing callback */ 2185 channel_cancel_cleanup(s->chanid); 2186 2187 /* Close any X11 listeners associated with this session */ 2188 if (s->x11_chanids != NULL) { 2189 for (i = 0; s->x11_chanids[i] != -1; i++) { 2190 session_close_x11(s->x11_chanids[i]); 2191 s->x11_chanids[i] = -1; 2192 } 2193 } 2194 2195 s->chanid = -1; 2196 session_close(s); 2197} 2198 2199void 2200session_destroy_all(void (*closefunc)(Session *)) 2201{ 2202 int i; 2203 for (i = 0; i < sessions_nalloc; i++) { 2204 Session *s = &sessions[i]; 2205 if (s->used) { 2206 if (closefunc != NULL) 2207 closefunc(s); 2208 else 2209 session_close(s); 2210 } 2211 } 2212} 2213 2214static char * 2215session_tty_list(void) 2216{ 2217 static char buf[1024]; 2218 int i; 2219 buf[0] = '\0'; 2220 for (i = 0; i < sessions_nalloc; i++) { 2221 Session *s = &sessions[i]; 2222 if (s->used && s->ttyfd != -1) { 2223 if (buf[0] != '\0') 2224 strlcat(buf, ",", sizeof buf); 2225 strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf); 2226 } 2227 } 2228 if (buf[0] == '\0') 2229 strlcpy(buf, "notty", sizeof buf); 2230 return buf; 2231} 2232 2233void 2234session_proctitle(Session *s) 2235{ 2236 if (s->pw == NULL) 2237 error("no user for session %d", s->self); 2238 else 2239 setproctitle("%s@%s", s->pw->pw_name, session_tty_list()); 2240} 2241 2242int 2243session_setup_x11fwd(Session *s) 2244{ 2245 struct stat st; 2246 char display[512], auth_display[512]; 2247 char hostname[NI_MAXHOST]; 2248 u_int i; 2249 2250 if (no_x11_forwarding_flag) { 2251 packet_send_debug("X11 forwarding disabled in user configuration file."); 2252 return 0; 2253 } 2254 if (!options.x11_forwarding) { 2255 debug("X11 forwarding disabled in server configuration file."); 2256 return 0; 2257 } 2258 if (options.xauth_location == NULL || 2259 (stat(options.xauth_location, &st) == -1)) { 2260 packet_send_debug("No xauth program; cannot forward with spoofing."); 2261 return 0; 2262 } 2263 if (options.use_login) { 2264 packet_send_debug("X11 forwarding disabled; " 2265 "not compatible with UseLogin=yes."); 2266 return 0; 2267 } 2268 if (s->display != NULL) { 2269 debug("X11 display already set."); 2270 return 0; 2271 } 2272 if (x11_create_display_inet(options.x11_display_offset, 2273 options.x11_use_localhost, s->single_connection, 2274 &s->display_number, &s->x11_chanids) == -1) { 2275 debug("x11_create_display_inet failed."); 2276 return 0; 2277 } 2278 for (i = 0; s->x11_chanids[i] != -1; i++) { 2279 channel_register_cleanup(s->x11_chanids[i], 2280 session_close_single_x11, 0); 2281 } 2282 2283 /* Set up a suitable value for the DISPLAY variable. */ 2284 if (gethostname(hostname, sizeof(hostname)) < 0) 2285 fatal("gethostname: %.100s", strerror(errno)); 2286 /* 2287 * auth_display must be used as the displayname when the 2288 * authorization entry is added with xauth(1). This will be 2289 * different than the DISPLAY string for localhost displays. 2290 */ 2291 if (options.x11_use_localhost) { 2292 snprintf(display, sizeof display, "localhost:%u.%u", 2293 s->display_number, s->screen); 2294 snprintf(auth_display, sizeof auth_display, "unix:%u.%u", 2295 s->display_number, s->screen); 2296 s->display = xstrdup(display); 2297 s->auth_display = xstrdup(auth_display); 2298 } else { 2299 snprintf(display, sizeof display, "%.400s:%u.%u", hostname, 2300 s->display_number, s->screen); 2301 s->display = xstrdup(display); 2302 s->auth_display = xstrdup(display); 2303 } 2304 2305 return 1; 2306} 2307 2308static void 2309do_authenticated2(Authctxt *authctxt) 2310{ 2311 server_loop2(authctxt); 2312} 2313 2314void 2315do_cleanup(Authctxt *authctxt) 2316{ 2317 static int called = 0; 2318 2319 debug("do_cleanup"); 2320 2321 /* no cleanup if we're in the child for login shell */ 2322 if (is_child) 2323 return; 2324 2325 /* avoid double cleanup */ 2326 if (called) 2327 return; 2328 called = 1; 2329 2330 if (authctxt == NULL || !authctxt->authenticated) 2331 return; 2332#ifdef KRB5 2333 if (options.kerberos_ticket_cleanup && 2334 authctxt->krb5_ctx) 2335 krb5_cleanup_proc(authctxt); 2336#endif 2337 2338#ifdef GSSAPI 2339 if (compat20 && options.gss_cleanup_creds) 2340 ssh_gssapi_cleanup_creds(); 2341#endif 2342 2343 /* remove agent socket */ 2344 auth_sock_cleanup_proc(authctxt->pw); 2345 2346 /* 2347 * Cleanup ptys/utmp only if privsep is disabled, 2348 * or if running in monitor. 2349 */ 2350 if (!use_privsep || mm_is_monitor()) 2351 session_destroy_all(session_pty_cleanup2); 2352} 2353