1/* $OpenBSD: session.c,v 1.338 2024/05/17 00:30:24 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 <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 <ctype.h> 44#include <errno.h> 45#include <fcntl.h> 46#include <grp.h> 47#include <login_cap.h> 48#include <netdb.h> 49#include <paths.h> 50#include <pwd.h> 51#include <signal.h> 52#include <stdio.h> 53#include <stdlib.h> 54#include <string.h> 55#include <stdarg.h> 56#include <unistd.h> 57#include <limits.h> 58 59#include "xmalloc.h" 60#include "ssh.h" 61#include "ssh2.h" 62#include "sshpty.h" 63#include "packet.h" 64#include "sshbuf.h" 65#include "ssherr.h" 66#include "match.h" 67#include "uidswap.h" 68#include "channels.h" 69#include "sshkey.h" 70#include "cipher.h" 71#include "kex.h" 72#include "hostfile.h" 73#include "auth.h" 74#include "auth-options.h" 75#include "authfd.h" 76#include "pathnames.h" 77#include "log.h" 78#include "misc.h" 79#include "servconf.h" 80#include "sshlogin.h" 81#include "serverloop.h" 82#include "canohost.h" 83#include "session.h" 84#ifdef GSSAPI 85#include "ssh-gss.h" 86#endif 87#include "monitor_wrap.h" 88#include "sftp.h" 89#include "atomicio.h" 90 91#ifdef KRB5 92#include <kafs.h> 93#endif 94 95#define IS_INTERNAL_SFTP(c) \ 96 (!strncmp(c, INTERNAL_SFTP_NAME, sizeof(INTERNAL_SFTP_NAME) - 1) && \ 97 (c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\0' || \ 98 c[sizeof(INTERNAL_SFTP_NAME) - 1] == ' ' || \ 99 c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\t')) 100 101/* func */ 102 103Session *session_new(void); 104void session_set_fds(struct ssh *, Session *, int, int, int, int, int); 105void session_pty_cleanup(Session *); 106void session_proctitle(Session *); 107int session_setup_x11fwd(struct ssh *, Session *); 108int do_exec_pty(struct ssh *, Session *, const char *); 109int do_exec_no_pty(struct ssh *, Session *, const char *); 110int do_exec(struct ssh *, Session *, const char *); 111void do_login(struct ssh *, Session *, const char *); 112void do_child(struct ssh *, Session *, const char *); 113void do_motd(void); 114int check_quietlogin(Session *, const char *); 115 116static void do_authenticated2(struct ssh *, Authctxt *); 117 118static int session_pty_req(struct ssh *, Session *); 119 120/* import */ 121extern ServerOptions options; 122extern char *__progname; 123extern int debug_flag; 124extern u_int utmp_len; 125extern int startup_pipe; 126extern void destroy_sensitive_data(void); 127extern struct sshbuf *loginmsg; 128extern struct sshauthopt *auth_opts; 129extern char *tun_fwd_ifnames; /* serverloop.c */ 130 131/* original command from peer. */ 132const char *original_command = NULL; 133 134/* data */ 135static int sessions_first_unused = -1; 136static int sessions_nalloc = 0; 137static Session *sessions = NULL; 138 139#define SUBSYSTEM_NONE 0 140#define SUBSYSTEM_EXT 1 141#define SUBSYSTEM_INT_SFTP 2 142#define SUBSYSTEM_INT_SFTP_ERROR 3 143 144login_cap_t *lc; 145 146static int is_child = 0; 147static int in_chroot = 0; 148 149/* File containing userauth info, if ExposeAuthInfo set */ 150static char *auth_info_file = NULL; 151 152/* Name and directory of socket for authentication agent forwarding. */ 153static char *auth_sock_name = NULL; 154static char *auth_sock_dir = NULL; 155 156/* removes the agent forwarding socket */ 157 158static void 159auth_sock_cleanup_proc(struct passwd *pw) 160{ 161 if (auth_sock_name != NULL) { 162 temporarily_use_uid(pw); 163 unlink(auth_sock_name); 164 rmdir(auth_sock_dir); 165 auth_sock_name = NULL; 166 restore_uid(); 167 } 168} 169 170static int 171auth_input_request_forwarding(struct ssh *ssh, struct passwd * pw) 172{ 173 Channel *nc; 174 int sock = -1; 175 176 if (auth_sock_name != NULL) { 177 error("authentication forwarding requested twice."); 178 return 0; 179 } 180 181 /* Temporarily drop privileged uid for mkdir/bind. */ 182 temporarily_use_uid(pw); 183 184 /* Allocate a buffer for the socket name, and format the name. */ 185 auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX"); 186 187 /* Create private directory for socket */ 188 if (mkdtemp(auth_sock_dir) == NULL) { 189 ssh_packet_send_debug(ssh, "Agent forwarding disabled: " 190 "mkdtemp() failed: %.100s", strerror(errno)); 191 restore_uid(); 192 free(auth_sock_dir); 193 auth_sock_dir = NULL; 194 goto authsock_err; 195 } 196 197 xasprintf(&auth_sock_name, "%s/agent.%ld", 198 auth_sock_dir, (long) getpid()); 199 200 /* Start a Unix listener on auth_sock_name. */ 201 sock = unix_listener(auth_sock_name, SSH_LISTEN_BACKLOG, 0); 202 203 /* Restore the privileged uid. */ 204 restore_uid(); 205 206 /* Check for socket/bind/listen failure. */ 207 if (sock < 0) 208 goto authsock_err; 209 210 /* Allocate a channel for the authentication agent socket. */ 211 nc = channel_new(ssh, "auth-listener", 212 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1, 213 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 214 0, "auth socket", 1); 215 nc->path = xstrdup(auth_sock_name); 216 return 1; 217 218 authsock_err: 219 free(auth_sock_name); 220 if (auth_sock_dir != NULL) { 221 temporarily_use_uid(pw); 222 rmdir(auth_sock_dir); 223 restore_uid(); 224 free(auth_sock_dir); 225 } 226 if (sock != -1) 227 close(sock); 228 auth_sock_name = NULL; 229 auth_sock_dir = NULL; 230 return 0; 231} 232 233static void 234display_loginmsg(void) 235{ 236 int r; 237 238 if (sshbuf_len(loginmsg) == 0) 239 return; 240 if ((r = sshbuf_put_u8(loginmsg, 0)) != 0) 241 fatal_fr(r, "sshbuf_put_u8"); 242 printf("%s", (char *)sshbuf_ptr(loginmsg)); 243 sshbuf_reset(loginmsg); 244} 245 246static void 247prepare_auth_info_file(struct passwd *pw, struct sshbuf *info) 248{ 249 int fd = -1, success = 0; 250 251 if (!options.expose_userauth_info || info == NULL) 252 return; 253 254 temporarily_use_uid(pw); 255 auth_info_file = xstrdup("/tmp/sshauth.XXXXXXXXXXXXXXX"); 256 if ((fd = mkstemp(auth_info_file)) == -1) { 257 error_f("mkstemp: %s", strerror(errno)); 258 goto out; 259 } 260 if (atomicio(vwrite, fd, sshbuf_mutable_ptr(info), 261 sshbuf_len(info)) != sshbuf_len(info)) { 262 error_f("write: %s", strerror(errno)); 263 goto out; 264 } 265 if (close(fd) != 0) { 266 error_f("close: %s", strerror(errno)); 267 goto out; 268 } 269 success = 1; 270 out: 271 if (!success) { 272 if (fd != -1) 273 close(fd); 274 free(auth_info_file); 275 auth_info_file = NULL; 276 } 277 restore_uid(); 278} 279 280static void 281set_fwdpermit_from_authopts(struct ssh *ssh, const struct sshauthopt *opts) 282{ 283 char *tmp, *cp, *host; 284 int port; 285 size_t i; 286 287 if ((options.allow_tcp_forwarding & FORWARD_LOCAL) != 0) { 288 channel_clear_permission(ssh, FORWARD_USER, FORWARD_LOCAL); 289 for (i = 0; i < auth_opts->npermitopen; i++) { 290 tmp = cp = xstrdup(auth_opts->permitopen[i]); 291 /* This shouldn't fail as it has already been checked */ 292 if ((host = hpdelim2(&cp, NULL)) == NULL) 293 fatal_f("internal error: hpdelim"); 294 host = cleanhostname(host); 295 if (cp == NULL || (port = permitopen_port(cp)) < 0) 296 fatal_f("internal error: permitopen port"); 297 channel_add_permission(ssh, 298 FORWARD_USER, FORWARD_LOCAL, host, port); 299 free(tmp); 300 } 301 } 302 if ((options.allow_tcp_forwarding & FORWARD_REMOTE) != 0) { 303 channel_clear_permission(ssh, FORWARD_USER, FORWARD_REMOTE); 304 for (i = 0; i < auth_opts->npermitlisten; i++) { 305 tmp = cp = xstrdup(auth_opts->permitlisten[i]); 306 /* This shouldn't fail as it has already been checked */ 307 if ((host = hpdelim(&cp)) == NULL) 308 fatal_f("internal error: hpdelim"); 309 host = cleanhostname(host); 310 if (cp == NULL || (port = permitopen_port(cp)) < 0) 311 fatal_f("internal error: permitlisten port"); 312 channel_add_permission(ssh, 313 FORWARD_USER, FORWARD_REMOTE, host, port); 314 free(tmp); 315 } 316 } 317} 318 319void 320do_authenticated(struct ssh *ssh, Authctxt *authctxt) 321{ 322 setproctitle("%s", authctxt->pw->pw_name); 323 324 auth_log_authopts("active", auth_opts, 0); 325 326 /* setup the channel layer */ 327 /* XXX - streamlocal? */ 328 set_fwdpermit_from_authopts(ssh, auth_opts); 329 330 if (!auth_opts->permit_port_forwarding_flag || 331 options.disable_forwarding) { 332 channel_disable_admin(ssh, FORWARD_LOCAL); 333 channel_disable_admin(ssh, FORWARD_REMOTE); 334 } else { 335 if ((options.allow_tcp_forwarding & FORWARD_LOCAL) == 0) 336 channel_disable_admin(ssh, FORWARD_LOCAL); 337 else 338 channel_permit_all(ssh, FORWARD_LOCAL); 339 if ((options.allow_tcp_forwarding & FORWARD_REMOTE) == 0) 340 channel_disable_admin(ssh, FORWARD_REMOTE); 341 else 342 channel_permit_all(ssh, FORWARD_REMOTE); 343 } 344 auth_debug_send(ssh); 345 346 prepare_auth_info_file(authctxt->pw, authctxt->session_info); 347 348 do_authenticated2(ssh, authctxt); 349 350 do_cleanup(ssh, authctxt); 351} 352 353/* Check untrusted xauth strings for metacharacters */ 354static int 355xauth_valid_string(const char *s) 356{ 357 size_t i; 358 359 for (i = 0; s[i] != '\0'; i++) { 360 if (!isalnum((u_char)s[i]) && 361 s[i] != '.' && s[i] != ':' && s[i] != '/' && 362 s[i] != '-' && s[i] != '_') 363 return 0; 364 } 365 return 1; 366} 367 368#define USE_PIPES 1 369/* 370 * This is called to fork and execute a command when we have no tty. This 371 * will call do_child from the child, and server_loop from the parent after 372 * setting up file descriptors and such. 373 */ 374int 375do_exec_no_pty(struct ssh *ssh, Session *s, const char *command) 376{ 377 pid_t pid; 378#ifdef USE_PIPES 379 int pin[2], pout[2], perr[2]; 380 381 if (s == NULL) 382 fatal("do_exec_no_pty: no session"); 383 384 /* Allocate pipes for communicating with the program. */ 385 if (pipe(pin) == -1) { 386 error_f("pipe in: %.100s", strerror(errno)); 387 return -1; 388 } 389 if (pipe(pout) == -1) { 390 error_f("pipe out: %.100s", strerror(errno)); 391 close(pin[0]); 392 close(pin[1]); 393 return -1; 394 } 395 if (pipe(perr) == -1) { 396 error_f("pipe err: %.100s", strerror(errno)); 397 close(pin[0]); 398 close(pin[1]); 399 close(pout[0]); 400 close(pout[1]); 401 return -1; 402 } 403#else 404 int inout[2], err[2]; 405 406 if (s == NULL) 407 fatal("do_exec_no_pty: no session"); 408 409 /* Uses socket pairs to communicate with the program. */ 410 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) == -1) { 411 error_f("socketpair #1: %.100s", strerror(errno)); 412 return -1; 413 } 414 if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) == -1) { 415 error_f("socketpair #2: %.100s", strerror(errno)); 416 close(inout[0]); 417 close(inout[1]); 418 return -1; 419 } 420#endif 421 422 session_proctitle(s); 423 424 /* Fork the child. */ 425 switch ((pid = fork())) { 426 case -1: 427 error_f("fork: %.100s", strerror(errno)); 428#ifdef USE_PIPES 429 close(pin[0]); 430 close(pin[1]); 431 close(pout[0]); 432 close(pout[1]); 433 close(perr[0]); 434 close(perr[1]); 435#else 436 close(inout[0]); 437 close(inout[1]); 438 close(err[0]); 439 close(err[1]); 440#endif 441 return -1; 442 case 0: 443 is_child = 1; 444 445 /* 446 * Create a new session and process group since the 4.4BSD 447 * setlogin() affects the entire process group. 448 */ 449 if (setsid() == -1) 450 error("setsid failed: %.100s", strerror(errno)); 451 452#ifdef USE_PIPES 453 /* 454 * Redirect stdin. We close the parent side of the socket 455 * pair, and make the child side the standard input. 456 */ 457 close(pin[1]); 458 if (dup2(pin[0], 0) == -1) 459 perror("dup2 stdin"); 460 close(pin[0]); 461 462 /* Redirect stdout. */ 463 close(pout[0]); 464 if (dup2(pout[1], 1) == -1) 465 perror("dup2 stdout"); 466 close(pout[1]); 467 468 /* Redirect stderr. */ 469 close(perr[0]); 470 if (dup2(perr[1], 2) == -1) 471 perror("dup2 stderr"); 472 close(perr[1]); 473#else 474 /* 475 * Redirect stdin, stdout, and stderr. Stdin and stdout will 476 * use the same socket, as some programs (particularly rdist) 477 * seem to depend on it. 478 */ 479 close(inout[1]); 480 close(err[1]); 481 if (dup2(inout[0], 0) == -1) /* stdin */ 482 perror("dup2 stdin"); 483 if (dup2(inout[0], 1) == -1) /* stdout (same as stdin) */ 484 perror("dup2 stdout"); 485 close(inout[0]); 486 if (dup2(err[0], 2) == -1) /* stderr */ 487 perror("dup2 stderr"); 488 close(err[0]); 489#endif 490 491 /* Do processing for the child (exec command etc). */ 492 do_child(ssh, s, command); 493 /* NOTREACHED */ 494 default: 495 break; 496 } 497 498 s->pid = pid; 499 /* Set interactive/non-interactive mode. */ 500 ssh_packet_set_interactive(ssh, s->display != NULL, 501 options.ip_qos_interactive, options.ip_qos_bulk); 502 503#ifdef USE_PIPES 504 /* We are the parent. Close the child sides of the pipes. */ 505 close(pin[0]); 506 close(pout[1]); 507 close(perr[1]); 508 509 session_set_fds(ssh, s, pin[1], pout[0], perr[0], 510 s->is_subsystem, 0); 511#else 512 /* We are the parent. Close the child sides of the socket pairs. */ 513 close(inout[0]); 514 close(err[0]); 515 516 /* 517 * Enter the interactive session. Note: server_loop must be able to 518 * handle the case that fdin and fdout are the same. 519 */ 520 session_set_fds(ssh, s, inout[1], inout[1], err[1], 521 s->is_subsystem, 0); 522#endif 523 return 0; 524} 525 526/* 527 * This is called to fork and execute a command when we have a tty. This 528 * will call do_child from the child, and server_loop from the parent after 529 * setting up file descriptors, controlling tty, updating wtmp, utmp, 530 * lastlog, and other such operations. 531 */ 532int 533do_exec_pty(struct ssh *ssh, Session *s, const char *command) 534{ 535 int fdout, ptyfd, ttyfd, ptymaster; 536 pid_t pid; 537 538 if (s == NULL) 539 fatal("do_exec_pty: no session"); 540 ptyfd = s->ptyfd; 541 ttyfd = s->ttyfd; 542 543 /* 544 * Create another descriptor of the pty master side for use as the 545 * standard input. We could use the original descriptor, but this 546 * simplifies code in server_loop. The descriptor is bidirectional. 547 * Do this before forking (and cleanup in the child) so as to 548 * detect and gracefully fail out-of-fd conditions. 549 */ 550 if ((fdout = dup(ptyfd)) == -1) { 551 error_f("dup #1: %s", strerror(errno)); 552 close(ttyfd); 553 close(ptyfd); 554 return -1; 555 } 556 /* we keep a reference to the pty master */ 557 if ((ptymaster = dup(ptyfd)) == -1) { 558 error_f("dup #2: %s", strerror(errno)); 559 close(ttyfd); 560 close(ptyfd); 561 close(fdout); 562 return -1; 563 } 564 565 /* Fork the child. */ 566 switch ((pid = fork())) { 567 case -1: 568 error_f("fork: %.100s", strerror(errno)); 569 close(fdout); 570 close(ptymaster); 571 close(ttyfd); 572 close(ptyfd); 573 return -1; 574 case 0: 575 is_child = 1; 576 577 close(fdout); 578 close(ptymaster); 579 580 /* Close the master side of the pseudo tty. */ 581 close(ptyfd); 582 583 /* Make the pseudo tty our controlling tty. */ 584 pty_make_controlling_tty(&ttyfd, s->tty); 585 586 /* Redirect stdin/stdout/stderr from the pseudo tty. */ 587 if (dup2(ttyfd, 0) == -1) 588 error("dup2 stdin: %s", strerror(errno)); 589 if (dup2(ttyfd, 1) == -1) 590 error("dup2 stdout: %s", strerror(errno)); 591 if (dup2(ttyfd, 2) == -1) 592 error("dup2 stderr: %s", strerror(errno)); 593 594 /* Close the extra descriptor for the pseudo tty. */ 595 close(ttyfd); 596 597 /* record login, etc. similar to login(1) */ 598 do_login(ssh, s, command); 599 600 /* 601 * Do common processing for the child, such as execing 602 * the command. 603 */ 604 do_child(ssh, s, command); 605 /* NOTREACHED */ 606 default: 607 break; 608 } 609 s->pid = pid; 610 611 /* Parent. Close the slave side of the pseudo tty. */ 612 close(ttyfd); 613 614 /* Enter interactive session. */ 615 s->ptymaster = ptymaster; 616 ssh_packet_set_interactive(ssh, 1, 617 options.ip_qos_interactive, options.ip_qos_bulk); 618 session_set_fds(ssh, s, ptyfd, fdout, -1, 1, 1); 619 return 0; 620} 621 622/* 623 * This is called to fork and execute a command. If another command is 624 * to be forced, execute that instead. 625 */ 626int 627do_exec(struct ssh *ssh, Session *s, const char *command) 628{ 629 int ret; 630 const char *forced = NULL, *tty = NULL; 631 char session_type[1024]; 632 633 if (options.adm_forced_command) { 634 original_command = command; 635 command = options.adm_forced_command; 636 forced = "(config)"; 637 } else if (auth_opts->force_command != NULL) { 638 original_command = command; 639 command = auth_opts->force_command; 640 forced = "(key-option)"; 641 } 642 s->forced = 0; 643 if (forced != NULL) { 644 s->forced = 1; 645 if (IS_INTERNAL_SFTP(command)) { 646 s->is_subsystem = s->is_subsystem ? 647 SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR; 648 } else if (s->is_subsystem) 649 s->is_subsystem = SUBSYSTEM_EXT; 650 snprintf(session_type, sizeof(session_type), 651 "forced-command %s '%.900s'", forced, command); 652 } else if (s->is_subsystem) { 653 snprintf(session_type, sizeof(session_type), 654 "subsystem '%.900s'", s->subsys); 655 } else if (command == NULL) { 656 snprintf(session_type, sizeof(session_type), "shell"); 657 } else { 658 /* NB. we don't log unforced commands to preserve privacy */ 659 snprintf(session_type, sizeof(session_type), "command"); 660 } 661 662 if (s->ttyfd != -1) { 663 tty = s->tty; 664 if (strncmp(tty, "/dev/", 5) == 0) 665 tty += 5; 666 } 667 668 verbose("Starting session: %s%s%s for %s from %.200s port %d id %d", 669 session_type, 670 tty == NULL ? "" : " on ", 671 tty == NULL ? "" : tty, 672 s->pw->pw_name, 673 ssh_remote_ipaddr(ssh), 674 ssh_remote_port(ssh), 675 s->self); 676 677#ifdef GSSAPI 678 if (options.gss_authentication) { 679 temporarily_use_uid(s->pw); 680 ssh_gssapi_storecreds(); 681 restore_uid(); 682 } 683#endif 684 if (s->ttyfd != -1) 685 ret = do_exec_pty(ssh, s, command); 686 else 687 ret = do_exec_no_pty(ssh, s, command); 688 689 original_command = NULL; 690 691 /* 692 * Clear loginmsg: it's the child's responsibility to display 693 * it to the user, otherwise multiple sessions may accumulate 694 * multiple copies of the login messages. 695 */ 696 sshbuf_reset(loginmsg); 697 698 return ret; 699} 700 701 702/* administrative, login(1)-like work */ 703void 704do_login(struct ssh *ssh, Session *s, const char *command) 705{ 706 socklen_t fromlen; 707 struct sockaddr_storage from; 708 709 /* 710 * Get IP address of client. If the connection is not a socket, let 711 * the address be 0.0.0.0. 712 */ 713 memset(&from, 0, sizeof(from)); 714 fromlen = sizeof(from); 715 if (ssh_packet_connection_is_on_socket(ssh)) { 716 if (getpeername(ssh_packet_get_connection_in(ssh), 717 (struct sockaddr *)&from, &fromlen) == -1) { 718 debug("getpeername: %.100s", strerror(errno)); 719 cleanup_exit(255); 720 } 721 } 722 723 if (check_quietlogin(s, command)) 724 return; 725 726 display_loginmsg(); 727 728 do_motd(); 729} 730 731/* 732 * Display the message of the day. 733 */ 734void 735do_motd(void) 736{ 737 FILE *f; 738 char buf[256]; 739 740 if (options.print_motd) { 741 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd", 742 "/etc/motd"), "r"); 743 if (f) { 744 while (fgets(buf, sizeof(buf), f)) 745 fputs(buf, stdout); 746 fclose(f); 747 } 748 } 749} 750 751 752/* 753 * Check for quiet login, either .hushlogin or command given. 754 */ 755int 756check_quietlogin(Session *s, const char *command) 757{ 758 char buf[256]; 759 struct passwd *pw = s->pw; 760 struct stat st; 761 762 /* Return 1 if .hushlogin exists or a command given. */ 763 if (command != NULL) 764 return 1; 765 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir); 766 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0) 767 return 1; 768 return 0; 769} 770 771/* 772 * Reads environment variables from the given file and adds/overrides them 773 * into the environment. If the file does not exist, this does nothing. 774 * Otherwise, it must consist of empty lines, comments (line starts with '#') 775 * and assignments of the form name=value. No other forms are allowed. 776 * If allowlist is not NULL, then it is interpreted as a pattern list and 777 * only variable names that match it will be accepted. 778 */ 779static void 780read_environment_file(char ***env, u_int *envsize, 781 const char *filename, const char *allowlist) 782{ 783 FILE *f; 784 char *line = NULL, *cp, *value; 785 size_t linesize = 0; 786 u_int lineno = 0; 787 788 f = fopen(filename, "r"); 789 if (!f) 790 return; 791 792 while (getline(&line, &linesize, f) != -1) { 793 if (++lineno > 1000) 794 fatal("Too many lines in environment file %s", filename); 795 for (cp = line; *cp == ' ' || *cp == '\t'; cp++) 796 ; 797 if (!*cp || *cp == '#' || *cp == '\n') 798 continue; 799 800 cp[strcspn(cp, "\n")] = '\0'; 801 802 value = strchr(cp, '='); 803 if (value == NULL) { 804 fprintf(stderr, "Bad line %u in %.100s\n", lineno, 805 filename); 806 continue; 807 } 808 /* 809 * Replace the equals sign by nul, and advance value to 810 * the value string. 811 */ 812 *value = '\0'; 813 value++; 814 if (allowlist != NULL && 815 match_pattern_list(cp, allowlist, 0) != 1) 816 continue; 817 child_set_env(env, envsize, cp, value); 818 } 819 free(line); 820 fclose(f); 821} 822 823static char ** 824do_setup_env(struct ssh *ssh, Session *s, const char *shell) 825{ 826 char buf[256]; 827 size_t n; 828 u_int i, envsize; 829 char *ocp, *cp, *value, **env, *laddr; 830 struct passwd *pw = s->pw; 831 832 /* Initialize the environment. */ 833 envsize = 100; 834 env = xcalloc(envsize, sizeof(char *)); 835 env[0] = NULL; 836 837#ifdef GSSAPI 838 /* Allow any GSSAPI methods that we've used to alter 839 * the child's environment as they see fit 840 */ 841 ssh_gssapi_do_child(&env, &envsize); 842#endif 843 844 /* Set basic environment. */ 845 for (i = 0; i < s->num_env; i++) 846 child_set_env(&env, &envsize, s->env[i].name, s->env[i].val); 847 848 child_set_env(&env, &envsize, "USER", pw->pw_name); 849 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name); 850 child_set_env(&env, &envsize, "HOME", pw->pw_dir); 851 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0) 852 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH); 853 else 854 child_set_env(&env, &envsize, "PATH", getenv("PATH")); 855 856 snprintf(buf, sizeof buf, "%.200s/%.50s", _PATH_MAILDIR, pw->pw_name); 857 child_set_env(&env, &envsize, "MAIL", buf); 858 859 /* Normal systems set SHELL by default. */ 860 child_set_env(&env, &envsize, "SHELL", shell); 861 862 if (getenv("TZ")) 863 child_set_env(&env, &envsize, "TZ", getenv("TZ")); 864 if (s->term) 865 child_set_env(&env, &envsize, "TERM", s->term); 866 if (s->display) 867 child_set_env(&env, &envsize, "DISPLAY", s->display); 868#ifdef KRB5 869 if (s->authctxt->krb5_ticket_file) 870 child_set_env(&env, &envsize, "KRB5CCNAME", 871 s->authctxt->krb5_ticket_file); 872#endif 873 if (auth_sock_name != NULL) 874 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME, 875 auth_sock_name); 876 877 878 /* Set custom environment options from pubkey authentication. */ 879 if (options.permit_user_env) { 880 for (n = 0 ; n < auth_opts->nenv; n++) { 881 ocp = xstrdup(auth_opts->env[n]); 882 cp = strchr(ocp, '='); 883 if (cp != NULL) { 884 *cp = '\0'; 885 /* Apply PermitUserEnvironment allowlist */ 886 if (options.permit_user_env_allowlist == NULL || 887 match_pattern_list(ocp, 888 options.permit_user_env_allowlist, 0) == 1) 889 child_set_env(&env, &envsize, 890 ocp, cp + 1); 891 } 892 free(ocp); 893 } 894 } 895 896 /* read $HOME/.ssh/environment. */ 897 if (options.permit_user_env) { 898 snprintf(buf, sizeof buf, "%.200s/%s/environment", 899 pw->pw_dir, _PATH_SSH_USER_DIR); 900 read_environment_file(&env, &envsize, buf, 901 options.permit_user_env_allowlist); 902 } 903 904 /* Environment specified by admin */ 905 for (i = 0; i < options.num_setenv; i++) { 906 cp = xstrdup(options.setenv[i]); 907 if ((value = strchr(cp, '=')) == NULL) { 908 /* shouldn't happen; vars are checked in servconf.c */ 909 fatal("Invalid config SetEnv: %s", options.setenv[i]); 910 } 911 *value++ = '\0'; 912 child_set_env(&env, &envsize, cp, value); 913 free(cp); 914 } 915 916 /* SSH_CLIENT deprecated */ 917 snprintf(buf, sizeof buf, "%.50s %d %d", 918 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 919 ssh_local_port(ssh)); 920 child_set_env(&env, &envsize, "SSH_CLIENT", buf); 921 922 laddr = get_local_ipaddr(ssh_packet_get_connection_in(ssh)); 923 snprintf(buf, sizeof buf, "%.50s %d %.50s %d", 924 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 925 laddr, ssh_local_port(ssh)); 926 free(laddr); 927 child_set_env(&env, &envsize, "SSH_CONNECTION", buf); 928 929 if (tun_fwd_ifnames != NULL) 930 child_set_env(&env, &envsize, "SSH_TUNNEL", tun_fwd_ifnames); 931 if (auth_info_file != NULL) 932 child_set_env(&env, &envsize, "SSH_USER_AUTH", auth_info_file); 933 if (s->ttyfd != -1) 934 child_set_env(&env, &envsize, "SSH_TTY", s->tty); 935 if (original_command) 936 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND", 937 original_command); 938 939 if (debug_flag) { 940 /* dump the environment */ 941 fprintf(stderr, "Environment:\n"); 942 for (i = 0; env[i]; i++) 943 fprintf(stderr, " %.200s\n", env[i]); 944 } 945 return env; 946} 947 948/* 949 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found 950 * first in this order). 951 */ 952static void 953do_rc_files(struct ssh *ssh, Session *s, const char *shell) 954{ 955 FILE *f = NULL; 956 char *cmd = NULL, *user_rc = NULL; 957 int do_xauth; 958 struct stat st; 959 960 do_xauth = 961 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL; 962 xasprintf(&user_rc, "%s/%s", s->pw->pw_dir, _PATH_SSH_USER_RC); 963 964 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */ 965 if (!s->is_subsystem && options.adm_forced_command == NULL && 966 auth_opts->permit_user_rc && options.permit_user_rc && 967 stat(user_rc, &st) >= 0) { 968 if (xasprintf(&cmd, "%s -c '%s %s'", shell, _PATH_BSHELL, 969 user_rc) == -1) 970 fatal_f("xasprintf: %s", strerror(errno)); 971 if (debug_flag) 972 fprintf(stderr, "Running %s\n", cmd); 973 f = popen(cmd, "w"); 974 if (f) { 975 if (do_xauth) 976 fprintf(f, "%s %s\n", s->auth_proto, 977 s->auth_data); 978 pclose(f); 979 } else 980 fprintf(stderr, "Could not run %s\n", 981 user_rc); 982 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) { 983 if (debug_flag) 984 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL, 985 _PATH_SSH_SYSTEM_RC); 986 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w"); 987 if (f) { 988 if (do_xauth) 989 fprintf(f, "%s %s\n", s->auth_proto, 990 s->auth_data); 991 pclose(f); 992 } else 993 fprintf(stderr, "Could not run %s\n", 994 _PATH_SSH_SYSTEM_RC); 995 } else if (do_xauth && options.xauth_location != NULL) { 996 /* Add authority data to .Xauthority if appropriate. */ 997 if (debug_flag) { 998 fprintf(stderr, 999 "Running %.500s remove %.100s\n", 1000 options.xauth_location, s->auth_display); 1001 fprintf(stderr, 1002 "%.500s add %.100s %.100s %.100s\n", 1003 options.xauth_location, s->auth_display, 1004 s->auth_proto, s->auth_data); 1005 } 1006 if (xasprintf(&cmd, "%s -q -", options.xauth_location) == -1) 1007 fatal_f("xasprintf: %s", strerror(errno)); 1008 f = popen(cmd, "w"); 1009 if (f) { 1010 fprintf(f, "remove %s\n", 1011 s->auth_display); 1012 fprintf(f, "add %s %s %s\n", 1013 s->auth_display, s->auth_proto, 1014 s->auth_data); 1015 pclose(f); 1016 } else { 1017 fprintf(stderr, "Could not run %s\n", 1018 cmd); 1019 } 1020 } 1021 free(cmd); 1022 free(user_rc); 1023} 1024 1025static void 1026do_nologin(struct passwd *pw) 1027{ 1028 FILE *f = NULL; 1029 char buf[1024], *nl, *def_nl = _PATH_NOLOGIN; 1030 struct stat sb; 1031 1032 if (login_getcapbool(lc, "ignorenologin", 0) || pw->pw_uid == 0) 1033 return; 1034 nl = login_getcapstr(lc, "nologin", def_nl, def_nl); 1035 1036 if (stat(nl, &sb) == -1) { 1037 if (nl != def_nl) 1038 free(nl); 1039 return; 1040 } 1041 1042 /* /etc/nologin exists. Print its contents if we can and exit. */ 1043 logit("User %.100s not allowed because %s exists", pw->pw_name, nl); 1044 if ((f = fopen(nl, "r")) != NULL) { 1045 while (fgets(buf, sizeof(buf), f)) 1046 fputs(buf, stderr); 1047 fclose(f); 1048 } 1049 exit(254); 1050} 1051 1052/* 1053 * Chroot into a directory after checking it for safety: all path components 1054 * must be root-owned directories with strict permissions. 1055 */ 1056static void 1057safely_chroot(const char *path, uid_t uid) 1058{ 1059 const char *cp; 1060 char component[PATH_MAX]; 1061 struct stat st; 1062 1063 if (!path_absolute(path)) 1064 fatal("chroot path does not begin at root"); 1065 if (strlen(path) >= sizeof(component)) 1066 fatal("chroot path too long"); 1067 1068 /* 1069 * Descend the path, checking that each component is a 1070 * root-owned directory with strict permissions. 1071 */ 1072 for (cp = path; cp != NULL;) { 1073 if ((cp = strchr(cp, '/')) == NULL) 1074 strlcpy(component, path, sizeof(component)); 1075 else { 1076 cp++; 1077 memcpy(component, path, cp - path); 1078 component[cp - path] = '\0'; 1079 } 1080 1081 debug3_f("checking '%s'", component); 1082 1083 if (stat(component, &st) != 0) 1084 fatal_f("stat(\"%s\"): %s", 1085 component, strerror(errno)); 1086 if (st.st_uid != 0 || (st.st_mode & 022) != 0) 1087 fatal("bad ownership or modes for chroot " 1088 "directory %s\"%s\"", 1089 cp == NULL ? "" : "component ", component); 1090 if (!S_ISDIR(st.st_mode)) 1091 fatal("chroot path %s\"%s\" is not a directory", 1092 cp == NULL ? "" : "component ", component); 1093 1094 } 1095 1096 if (chdir(path) == -1) 1097 fatal("Unable to chdir to chroot path \"%s\": " 1098 "%s", path, strerror(errno)); 1099 if (chroot(path) == -1) 1100 fatal("chroot(\"%s\"): %s", path, strerror(errno)); 1101 if (chdir("/") == -1) 1102 fatal_f("chdir(/) after chroot: %s", strerror(errno)); 1103 verbose("Changed root directory to \"%s\"", path); 1104} 1105 1106/* Set login name, uid, gid, and groups. */ 1107void 1108do_setusercontext(struct passwd *pw) 1109{ 1110 char uidstr[32], *chroot_path, *tmp; 1111 1112 if (getuid() == 0 || geteuid() == 0) { 1113 /* Prepare groups */ 1114 if (setusercontext(lc, pw, pw->pw_uid, 1115 (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) { 1116 perror("unable to set user context"); 1117 exit(1); 1118 } 1119 1120 if (!in_chroot && options.chroot_directory != NULL && 1121 strcasecmp(options.chroot_directory, "none") != 0) { 1122 tmp = tilde_expand_filename(options.chroot_directory, 1123 pw->pw_uid); 1124 snprintf(uidstr, sizeof(uidstr), "%llu", 1125 (unsigned long long)pw->pw_uid); 1126 chroot_path = percent_expand(tmp, "h", pw->pw_dir, 1127 "u", pw->pw_name, "U", uidstr, (char *)NULL); 1128 safely_chroot(chroot_path, pw->pw_uid); 1129 free(tmp); 1130 free(chroot_path); 1131 /* Make sure we don't attempt to chroot again */ 1132 free(options.chroot_directory); 1133 options.chroot_directory = NULL; 1134 in_chroot = 1; 1135 } 1136 1137 /* Set UID */ 1138 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) { 1139 perror("unable to set user context (setuser)"); 1140 exit(1); 1141 } 1142 } else if (options.chroot_directory != NULL && 1143 strcasecmp(options.chroot_directory, "none") != 0) { 1144 fatal("server lacks privileges to chroot to ChrootDirectory"); 1145 } 1146 1147 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid) 1148 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid); 1149} 1150 1151static void 1152do_pwchange(Session *s) 1153{ 1154 fflush(NULL); 1155 fprintf(stderr, "WARNING: Your password has expired.\n"); 1156 if (s->ttyfd != -1) { 1157 fprintf(stderr, 1158 "You must change your password now and login again!\n"); 1159 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL); 1160 perror("passwd"); 1161 } else { 1162 fprintf(stderr, 1163 "Password change required but no TTY available.\n"); 1164 } 1165 exit(1); 1166} 1167 1168static void 1169child_close_fds(struct ssh *ssh) 1170{ 1171 extern int auth_sock; 1172 1173 if (auth_sock != -1) { 1174 close(auth_sock); 1175 auth_sock = -1; 1176 } 1177 1178 if (ssh_packet_get_connection_in(ssh) == 1179 ssh_packet_get_connection_out(ssh)) 1180 close(ssh_packet_get_connection_in(ssh)); 1181 else { 1182 close(ssh_packet_get_connection_in(ssh)); 1183 close(ssh_packet_get_connection_out(ssh)); 1184 } 1185 /* 1186 * Close all descriptors related to channels. They will still remain 1187 * open in the parent. 1188 */ 1189 /* XXX better use close-on-exec? -markus */ 1190 channel_close_all(ssh); 1191 1192 /* 1193 * Close any extra file descriptors. Note that there may still be 1194 * descriptors left by system functions. They will be closed later. 1195 */ 1196 endpwent(); 1197 1198 /* Stop directing logs to a high-numbered fd before we close it */ 1199 log_redirect_stderr_to(NULL); 1200 1201 /* 1202 * Close any extra open file descriptors so that we don't have them 1203 * hanging around in clients. Note that we want to do this after 1204 * initgroups, because at least on Solaris 2.3 it leaves file 1205 * descriptors open. 1206 */ 1207 closefrom(STDERR_FILENO + 1); 1208} 1209 1210/* 1211 * Performs common processing for the child, such as setting up the 1212 * environment, closing extra file descriptors, setting the user and group 1213 * ids, and executing the command or shell. 1214 */ 1215#define ARGV_MAX 10 1216void 1217do_child(struct ssh *ssh, Session *s, const char *command) 1218{ 1219 extern char **environ; 1220 char **env, *argv[ARGV_MAX], remote_id[512]; 1221 const char *shell, *shell0; 1222 struct passwd *pw = s->pw; 1223 int r = 0; 1224 1225 sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id)); 1226 1227 /* remove hostkey from the child's memory */ 1228 destroy_sensitive_data(); 1229 ssh_packet_clear_keys(ssh); 1230 1231 /* Force a password change */ 1232 if (s->authctxt->force_pwchange) { 1233 do_setusercontext(pw); 1234 child_close_fds(ssh); 1235 do_pwchange(s); 1236 exit(1); 1237 } 1238 1239 /* 1240 * Login(1) does this as well, and it needs uid 0 for the "-h" 1241 * switch, so we let login(1) to this for us. 1242 */ 1243 do_nologin(pw); 1244 do_setusercontext(pw); 1245 1246 /* 1247 * Get the shell from the password data. An empty shell field is 1248 * legal, and means /bin/sh. 1249 */ 1250 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell; 1251 1252 /* 1253 * Make sure $SHELL points to the shell from the password file, 1254 * even if shell is overridden from login.conf 1255 */ 1256 env = do_setup_env(ssh, s, shell); 1257 1258 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell); 1259 1260 /* 1261 * Close the connection descriptors; note that this is the child, and 1262 * the server will still have the socket open, and it is important 1263 * that we do not shutdown it. Note that the descriptors cannot be 1264 * closed before building the environment, as we call 1265 * ssh_remote_ipaddr there. 1266 */ 1267 child_close_fds(ssh); 1268 1269 /* 1270 * Must take new environment into use so that .ssh/rc, 1271 * /etc/ssh/sshrc and xauth are run in the proper environment. 1272 */ 1273 environ = env; 1274 1275#ifdef KRB5 1276 /* 1277 * At this point, we check to see if AFS is active and if we have 1278 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see 1279 * if we can (and need to) extend the ticket into an AFS token. If 1280 * we don't do this, we run into potential problems if the user's 1281 * home directory is in AFS and it's not world-readable. 1282 */ 1283 1284 if (options.kerberos_get_afs_token && k_hasafs() && 1285 (s->authctxt->krb5_ctx != NULL)) { 1286 char cell[64]; 1287 1288 debug("Getting AFS token"); 1289 1290 k_setpag(); 1291 1292 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0) 1293 krb5_afslog(s->authctxt->krb5_ctx, 1294 s->authctxt->krb5_fwd_ccache, cell, NULL); 1295 1296 krb5_afslog_home(s->authctxt->krb5_ctx, 1297 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir); 1298 } 1299#endif 1300 1301 /* Change current directory to the user's home directory. */ 1302 if (chdir(pw->pw_dir) == -1) { 1303 /* Suppress missing homedir warning for chroot case */ 1304 r = login_getcapbool(lc, "requirehome", 0); 1305 if (r || !in_chroot) { 1306 fprintf(stderr, "Could not chdir to home " 1307 "directory %s: %s\n", pw->pw_dir, 1308 strerror(errno)); 1309 } 1310 if (r) 1311 exit(1); 1312 } 1313 1314 closefrom(STDERR_FILENO + 1); 1315 1316 do_rc_files(ssh, s, shell); 1317 1318 /* restore SIGPIPE for child */ 1319 ssh_signal(SIGPIPE, SIG_DFL); 1320 1321 if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) { 1322 error("Connection from %s: refusing non-sftp session", 1323 remote_id); 1324 printf("This service allows sftp connections only.\n"); 1325 fflush(NULL); 1326 exit(1); 1327 } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) { 1328 extern int optind, optreset; 1329 int i; 1330 char *p, *args; 1331 1332 setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME); 1333 args = xstrdup(command ? command : "sftp-server"); 1334 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " "))) 1335 if (i < ARGV_MAX - 1) 1336 argv[i++] = p; 1337 argv[i] = NULL; 1338 optind = optreset = 1; 1339 __progname = argv[0]; 1340 exit(sftp_server_main(i, argv, s->pw)); 1341 } 1342 1343 fflush(NULL); 1344 1345 /* Get the last component of the shell name. */ 1346 if ((shell0 = strrchr(shell, '/')) != NULL) 1347 shell0++; 1348 else 1349 shell0 = shell; 1350 1351 /* 1352 * If we have no command, execute the shell. In this case, the shell 1353 * name to be passed in argv[0] is preceded by '-' to indicate that 1354 * this is a login shell. 1355 */ 1356 if (!command) { 1357 char argv0[256]; 1358 1359 /* Start the shell. Set initial character to '-'. */ 1360 argv0[0] = '-'; 1361 1362 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1) 1363 >= sizeof(argv0) - 1) { 1364 errno = EINVAL; 1365 perror(shell); 1366 exit(1); 1367 } 1368 1369 /* Execute the shell. */ 1370 argv[0] = argv0; 1371 argv[1] = NULL; 1372 execve(shell, argv, env); 1373 1374 /* Executing the shell failed. */ 1375 perror(shell); 1376 exit(1); 1377 } 1378 /* 1379 * Execute the command using the user's shell. This uses the -c 1380 * option to execute the command. 1381 */ 1382 argv[0] = (char *) shell0; 1383 argv[1] = "-c"; 1384 argv[2] = (char *) command; 1385 argv[3] = NULL; 1386 execve(shell, argv, env); 1387 perror(shell); 1388 exit(1); 1389} 1390 1391void 1392session_unused(int id) 1393{ 1394 debug3_f("session id %d unused", id); 1395 if (id >= options.max_sessions || 1396 id >= sessions_nalloc) { 1397 fatal_f("insane session id %d (max %d nalloc %d)", 1398 id, options.max_sessions, sessions_nalloc); 1399 } 1400 memset(&sessions[id], 0, sizeof(*sessions)); 1401 sessions[id].self = id; 1402 sessions[id].used = 0; 1403 sessions[id].chanid = -1; 1404 sessions[id].ptyfd = -1; 1405 sessions[id].ttyfd = -1; 1406 sessions[id].ptymaster = -1; 1407 sessions[id].x11_chanids = NULL; 1408 sessions[id].next_unused = sessions_first_unused; 1409 sessions_first_unused = id; 1410} 1411 1412Session * 1413session_new(void) 1414{ 1415 Session *s, *tmp; 1416 1417 if (sessions_first_unused == -1) { 1418 if (sessions_nalloc >= options.max_sessions) 1419 return NULL; 1420 debug2_f("allocate (allocated %d max %d)", 1421 sessions_nalloc, options.max_sessions); 1422 tmp = xrecallocarray(sessions, sessions_nalloc, 1423 sessions_nalloc + 1, sizeof(*sessions)); 1424 if (tmp == NULL) { 1425 error_f("cannot allocate %d sessions", 1426 sessions_nalloc + 1); 1427 return NULL; 1428 } 1429 sessions = tmp; 1430 session_unused(sessions_nalloc++); 1431 } 1432 1433 if (sessions_first_unused >= sessions_nalloc || 1434 sessions_first_unused < 0) { 1435 fatal_f("insane first_unused %d max %d nalloc %d", 1436 sessions_first_unused, options.max_sessions, 1437 sessions_nalloc); 1438 } 1439 1440 s = &sessions[sessions_first_unused]; 1441 if (s->used) 1442 fatal_f("session %d already used", sessions_first_unused); 1443 sessions_first_unused = s->next_unused; 1444 s->used = 1; 1445 s->next_unused = -1; 1446 debug("session_new: session %d", s->self); 1447 1448 return s; 1449} 1450 1451static void 1452session_dump(void) 1453{ 1454 int i; 1455 for (i = 0; i < sessions_nalloc; i++) { 1456 Session *s = &sessions[i]; 1457 1458 debug("dump: used %d next_unused %d session %d " 1459 "channel %d pid %ld", 1460 s->used, 1461 s->next_unused, 1462 s->self, 1463 s->chanid, 1464 (long)s->pid); 1465 } 1466} 1467 1468int 1469session_open(Authctxt *authctxt, int chanid) 1470{ 1471 Session *s = session_new(); 1472 debug("session_open: channel %d", chanid); 1473 if (s == NULL) { 1474 error("no more sessions"); 1475 return 0; 1476 } 1477 s->authctxt = authctxt; 1478 s->pw = authctxt->pw; 1479 if (s->pw == NULL || !authctxt->valid) 1480 fatal("no user for session %d", s->self); 1481 debug("session_open: session %d: link with channel %d", s->self, chanid); 1482 s->chanid = chanid; 1483 return 1; 1484} 1485 1486Session * 1487session_by_tty(char *tty) 1488{ 1489 int i; 1490 for (i = 0; i < sessions_nalloc; i++) { 1491 Session *s = &sessions[i]; 1492 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) { 1493 debug("session_by_tty: session %d tty %s", i, tty); 1494 return s; 1495 } 1496 } 1497 debug("session_by_tty: unknown tty %.100s", tty); 1498 session_dump(); 1499 return NULL; 1500} 1501 1502static Session * 1503session_by_channel(int id) 1504{ 1505 int i; 1506 for (i = 0; i < sessions_nalloc; i++) { 1507 Session *s = &sessions[i]; 1508 if (s->used && s->chanid == id) { 1509 debug("session_by_channel: session %d channel %d", 1510 i, id); 1511 return s; 1512 } 1513 } 1514 debug("session_by_channel: unknown channel %d", id); 1515 session_dump(); 1516 return NULL; 1517} 1518 1519static Session * 1520session_by_x11_channel(int id) 1521{ 1522 int i, j; 1523 1524 for (i = 0; i < sessions_nalloc; i++) { 1525 Session *s = &sessions[i]; 1526 1527 if (s->x11_chanids == NULL || !s->used) 1528 continue; 1529 for (j = 0; s->x11_chanids[j] != -1; j++) { 1530 if (s->x11_chanids[j] == id) { 1531 debug("session_by_x11_channel: session %d " 1532 "channel %d", s->self, id); 1533 return s; 1534 } 1535 } 1536 } 1537 debug("session_by_x11_channel: unknown channel %d", id); 1538 session_dump(); 1539 return NULL; 1540} 1541 1542static Session * 1543session_by_pid(pid_t pid) 1544{ 1545 int i; 1546 debug("session_by_pid: pid %ld", (long)pid); 1547 for (i = 0; i < sessions_nalloc; i++) { 1548 Session *s = &sessions[i]; 1549 if (s->used && s->pid == pid) 1550 return s; 1551 } 1552 error("session_by_pid: unknown pid %ld", (long)pid); 1553 session_dump(); 1554 return NULL; 1555} 1556 1557static int 1558session_window_change_req(struct ssh *ssh, Session *s) 1559{ 1560 int r; 1561 1562 if ((r = sshpkt_get_u32(ssh, &s->col)) != 0 || 1563 (r = sshpkt_get_u32(ssh, &s->row)) != 0 || 1564 (r = sshpkt_get_u32(ssh, &s->xpixel)) != 0 || 1565 (r = sshpkt_get_u32(ssh, &s->ypixel)) != 0 || 1566 (r = sshpkt_get_end(ssh)) != 0) 1567 sshpkt_fatal(ssh, r, "%s: parse packet", __func__); 1568 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel); 1569 return 1; 1570} 1571 1572static int 1573session_pty_req(struct ssh *ssh, Session *s) 1574{ 1575 int r; 1576 1577 if (!auth_opts->permit_pty_flag || !options.permit_tty) { 1578 debug("Allocating a pty not permitted for this connection."); 1579 return 0; 1580 } 1581 if (s->ttyfd != -1) { 1582 ssh_packet_disconnect(ssh, "Protocol error: you already have a pty."); 1583 return 0; 1584 } 1585 1586 if ((r = sshpkt_get_cstring(ssh, &s->term, NULL)) != 0 || 1587 (r = sshpkt_get_u32(ssh, &s->col)) != 0 || 1588 (r = sshpkt_get_u32(ssh, &s->row)) != 0 || 1589 (r = sshpkt_get_u32(ssh, &s->xpixel)) != 0 || 1590 (r = sshpkt_get_u32(ssh, &s->ypixel)) != 0) 1591 sshpkt_fatal(ssh, r, "%s: parse packet", __func__); 1592 1593 if (strcmp(s->term, "") == 0) { 1594 free(s->term); 1595 s->term = NULL; 1596 } 1597 1598 /* Allocate a pty and open it. */ 1599 debug("Allocating pty."); 1600 if (!mm_pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, sizeof(s->tty))) { 1601 free(s->term); 1602 s->term = NULL; 1603 s->ptyfd = -1; 1604 s->ttyfd = -1; 1605 error("session_pty_req: session %d alloc failed", s->self); 1606 return 0; 1607 } 1608 debug("session_pty_req: session %d alloc %s", s->self, s->tty); 1609 1610 ssh_tty_parse_modes(ssh, s->ttyfd); 1611 1612 if ((r = sshpkt_get_end(ssh)) != 0) 1613 sshpkt_fatal(ssh, r, "%s: parse packet", __func__); 1614 1615 /* Set window size from the packet. */ 1616 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel); 1617 1618 session_proctitle(s); 1619 return 1; 1620} 1621 1622static int 1623session_subsystem_req(struct ssh *ssh, Session *s) 1624{ 1625 struct stat st; 1626 int r, success = 0; 1627 char *prog, *cmd, *type; 1628 u_int i; 1629 1630 if ((r = sshpkt_get_cstring(ssh, &s->subsys, NULL)) != 0 || 1631 (r = sshpkt_get_end(ssh)) != 0) 1632 sshpkt_fatal(ssh, r, "%s: parse packet", __func__); 1633 debug2("subsystem request for %.100s by user %s", s->subsys, 1634 s->pw->pw_name); 1635 1636 for (i = 0; i < options.num_subsystems; i++) { 1637 if (strcmp(s->subsys, options.subsystem_name[i]) == 0) { 1638 prog = options.subsystem_command[i]; 1639 cmd = options.subsystem_args[i]; 1640 if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) { 1641 s->is_subsystem = SUBSYSTEM_INT_SFTP; 1642 debug("subsystem: %s", prog); 1643 } else { 1644 if (stat(prog, &st) == -1) 1645 debug("subsystem: cannot stat %s: %s", 1646 prog, strerror(errno)); 1647 s->is_subsystem = SUBSYSTEM_EXT; 1648 debug("subsystem: exec() %s", cmd); 1649 } 1650 xasprintf(&type, "session:subsystem:%s", 1651 options.subsystem_name[i]); 1652 channel_set_xtype(ssh, s->chanid, type); 1653 free(type); 1654 success = do_exec(ssh, s, cmd) == 0; 1655 break; 1656 } 1657 } 1658 1659 if (!success) 1660 logit("subsystem request for %.100s by user %s failed, " 1661 "subsystem not found", s->subsys, s->pw->pw_name); 1662 1663 return success; 1664} 1665 1666static int 1667session_x11_req(struct ssh *ssh, Session *s) 1668{ 1669 int r, success; 1670 u_char single_connection = 0; 1671 1672 if (s->auth_proto != NULL || s->auth_data != NULL) { 1673 error("session_x11_req: session %d: " 1674 "x11 forwarding already active", s->self); 1675 return 0; 1676 } 1677 if ((r = sshpkt_get_u8(ssh, &single_connection)) != 0 || 1678 (r = sshpkt_get_cstring(ssh, &s->auth_proto, NULL)) != 0 || 1679 (r = sshpkt_get_cstring(ssh, &s->auth_data, NULL)) != 0 || 1680 (r = sshpkt_get_u32(ssh, &s->screen)) != 0 || 1681 (r = sshpkt_get_end(ssh)) != 0) 1682 sshpkt_fatal(ssh, r, "%s: parse packet", __func__); 1683 1684 s->single_connection = single_connection; 1685 1686 if (xauth_valid_string(s->auth_proto) && 1687 xauth_valid_string(s->auth_data)) 1688 success = session_setup_x11fwd(ssh, s); 1689 else { 1690 success = 0; 1691 error("Invalid X11 forwarding data"); 1692 } 1693 if (!success) { 1694 free(s->auth_proto); 1695 free(s->auth_data); 1696 s->auth_proto = NULL; 1697 s->auth_data = NULL; 1698 } 1699 return success; 1700} 1701 1702static int 1703session_shell_req(struct ssh *ssh, Session *s) 1704{ 1705 int r; 1706 1707 if ((r = sshpkt_get_end(ssh)) != 0) 1708 sshpkt_fatal(ssh, r, "%s: parse packet", __func__); 1709 1710 channel_set_xtype(ssh, s->chanid, "session:shell"); 1711 1712 return do_exec(ssh, s, NULL) == 0; 1713} 1714 1715static int 1716session_exec_req(struct ssh *ssh, Session *s) 1717{ 1718 u_int success; 1719 int r; 1720 char *command = NULL; 1721 1722 if ((r = sshpkt_get_cstring(ssh, &command, NULL)) != 0 || 1723 (r = sshpkt_get_end(ssh)) != 0) 1724 sshpkt_fatal(ssh, r, "%s: parse packet", __func__); 1725 1726 channel_set_xtype(ssh, s->chanid, "session:command"); 1727 1728 success = do_exec(ssh, s, command) == 0; 1729 free(command); 1730 return success; 1731} 1732 1733static int 1734session_break_req(struct ssh *ssh, Session *s) 1735{ 1736 int r; 1737 1738 if ((r = sshpkt_get_u32(ssh, NULL)) != 0 || /* ignore */ 1739 (r = sshpkt_get_end(ssh)) != 0) 1740 sshpkt_fatal(ssh, r, "%s: parse packet", __func__); 1741 1742 if (s->ptymaster == -1 || tcsendbreak(s->ptymaster, 0) == -1) 1743 return 0; 1744 return 1; 1745} 1746 1747static int 1748session_env_req(struct ssh *ssh, Session *s) 1749{ 1750 char *name, *val; 1751 u_int i; 1752 int r; 1753 1754 if ((r = sshpkt_get_cstring(ssh, &name, NULL)) != 0 || 1755 (r = sshpkt_get_cstring(ssh, &val, NULL)) != 0 || 1756 (r = sshpkt_get_end(ssh)) != 0) 1757 sshpkt_fatal(ssh, r, "%s: parse packet", __func__); 1758 1759 /* Don't set too many environment variables */ 1760 if (s->num_env > 128) { 1761 debug2("Ignoring env request %s: too many env vars", name); 1762 goto fail; 1763 } 1764 1765 for (i = 0; i < options.num_accept_env; i++) { 1766 if (match_pattern(name, options.accept_env[i])) { 1767 debug2("Setting env %d: %s=%s", s->num_env, name, val); 1768 s->env = xrecallocarray(s->env, s->num_env, 1769 s->num_env + 1, sizeof(*s->env)); 1770 s->env[s->num_env].name = name; 1771 s->env[s->num_env].val = val; 1772 s->num_env++; 1773 return (1); 1774 } 1775 } 1776 debug2("Ignoring env request %s: disallowed name", name); 1777 1778 fail: 1779 free(name); 1780 free(val); 1781 return (0); 1782} 1783 1784/* 1785 * Conversion of signals from ssh channel request names. 1786 * Subset of signals from RFC 4254 section 6.10C, with SIGINFO as 1787 * local extension. 1788 */ 1789static int 1790name2sig(char *name) 1791{ 1792#define SSH_SIG(x) if (strcmp(name, #x) == 0) return SIG ## x 1793 SSH_SIG(HUP); 1794 SSH_SIG(INT); 1795 SSH_SIG(KILL); 1796 SSH_SIG(QUIT); 1797 SSH_SIG(TERM); 1798 SSH_SIG(USR1); 1799 SSH_SIG(USR2); 1800#undef SSH_SIG 1801 if (strcmp(name, "INFO@openssh.com") == 0) 1802 return SIGINFO; 1803 return -1; 1804} 1805 1806static int 1807session_signal_req(struct ssh *ssh, Session *s) 1808{ 1809 char *signame = NULL; 1810 int r, sig, success = 0; 1811 1812 if ((r = sshpkt_get_cstring(ssh, &signame, NULL)) != 0 || 1813 (r = sshpkt_get_end(ssh)) != 0) { 1814 error_fr(r, "parse"); 1815 goto out; 1816 } 1817 if ((sig = name2sig(signame)) == -1) { 1818 error_f("unsupported signal \"%s\"", signame); 1819 goto out; 1820 } 1821 if (s->pid <= 0) { 1822 error_f("no pid for session %d", s->self); 1823 goto out; 1824 } 1825 if (s->forced || s->is_subsystem) { 1826 error_f("refusing to send signal %s to %s session", 1827 signame, s->forced ? "forced-command" : "subsystem"); 1828 goto out; 1829 } 1830 if (mm_is_monitor()) { 1831 error_f("session signalling requires privilege separation"); 1832 goto out; 1833 } 1834 1835 debug_f("signal %s, killpg(%ld, %d)", signame, (long)s->pid, sig); 1836 temporarily_use_uid(s->pw); 1837 r = killpg(s->pid, sig); 1838 restore_uid(); 1839 if (r != 0) { 1840 error_f("killpg(%ld, %d): %s", (long)s->pid, 1841 sig, strerror(errno)); 1842 goto out; 1843 } 1844 1845 /* success */ 1846 success = 1; 1847 out: 1848 free(signame); 1849 return success; 1850} 1851 1852static int 1853session_auth_agent_req(struct ssh *ssh, Session *s) 1854{ 1855 static int called = 0; 1856 int r; 1857 1858 if ((r = sshpkt_get_end(ssh)) != 0) 1859 sshpkt_fatal(ssh, r, "%s: parse packet", __func__); 1860 if (!auth_opts->permit_agent_forwarding_flag || 1861 !options.allow_agent_forwarding) { 1862 debug_f("agent forwarding disabled"); 1863 return 0; 1864 } 1865 if (called) { 1866 return 0; 1867 } else { 1868 called = 1; 1869 return auth_input_request_forwarding(ssh, s->pw); 1870 } 1871} 1872 1873int 1874session_input_channel_req(struct ssh *ssh, Channel *c, const char *rtype) 1875{ 1876 int success = 0; 1877 Session *s; 1878 1879 if ((s = session_by_channel(c->self)) == NULL) { 1880 logit_f("no session %d req %.100s", c->self, rtype); 1881 return 0; 1882 } 1883 debug_f("session %d req %s", s->self, rtype); 1884 1885 /* 1886 * a session is in LARVAL state until a shell, a command 1887 * or a subsystem is executed 1888 */ 1889 if (c->type == SSH_CHANNEL_LARVAL) { 1890 if (strcmp(rtype, "shell") == 0) { 1891 success = session_shell_req(ssh, s); 1892 } else if (strcmp(rtype, "exec") == 0) { 1893 success = session_exec_req(ssh, s); 1894 } else if (strcmp(rtype, "pty-req") == 0) { 1895 success = session_pty_req(ssh, s); 1896 } else if (strcmp(rtype, "x11-req") == 0) { 1897 success = session_x11_req(ssh, s); 1898 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) { 1899 success = session_auth_agent_req(ssh, s); 1900 } else if (strcmp(rtype, "subsystem") == 0) { 1901 success = session_subsystem_req(ssh, s); 1902 } else if (strcmp(rtype, "env") == 0) { 1903 success = session_env_req(ssh, s); 1904 } 1905 } 1906 if (strcmp(rtype, "window-change") == 0) { 1907 success = session_window_change_req(ssh, s); 1908 } else if (strcmp(rtype, "break") == 0) { 1909 success = session_break_req(ssh, s); 1910 } else if (strcmp(rtype, "signal") == 0) { 1911 success = session_signal_req(ssh, s); 1912 } 1913 1914 return success; 1915} 1916 1917void 1918session_set_fds(struct ssh *ssh, Session *s, 1919 int fdin, int fdout, int fderr, int ignore_fderr, int is_tty) 1920{ 1921 /* 1922 * now that have a child and a pipe to the child, 1923 * we can activate our channel and register the fd's 1924 */ 1925 if (s->chanid == -1) 1926 fatal("no channel for session %d", s->self); 1927 channel_set_fds(ssh, s->chanid, 1928 fdout, fdin, fderr, 1929 ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ, 1930 1, is_tty, CHAN_SES_WINDOW_DEFAULT); 1931} 1932 1933/* 1934 * Function to perform pty cleanup. Also called if we get aborted abnormally 1935 * (e.g., due to a dropped connection). 1936 */ 1937void 1938session_pty_cleanup2(Session *s) 1939{ 1940 if (s == NULL) { 1941 error_f("no session"); 1942 return; 1943 } 1944 if (s->ttyfd == -1) 1945 return; 1946 1947 debug_f("session %d release %s", s->self, s->tty); 1948 1949 /* Record that the user has logged out. */ 1950 if (s->pid != 0) 1951 record_logout(s->pid, s->tty); 1952 1953 /* Release the pseudo-tty. */ 1954 if (getuid() == 0) 1955 pty_release(s->tty); 1956 1957 /* 1958 * Close the server side of the socket pairs. We must do this after 1959 * the pty cleanup, so that another process doesn't get this pty 1960 * while we're still cleaning up. 1961 */ 1962 if (s->ptymaster != -1 && close(s->ptymaster) == -1) 1963 error("close(s->ptymaster/%d): %s", 1964 s->ptymaster, strerror(errno)); 1965 1966 /* unlink pty from session */ 1967 s->ttyfd = -1; 1968} 1969 1970void 1971session_pty_cleanup(Session *s) 1972{ 1973 mm_session_pty_cleanup2(s); 1974} 1975 1976static char * 1977sig2name(int sig) 1978{ 1979#define SSH_SIG(x) if (sig == SIG ## x) return #x 1980 SSH_SIG(ABRT); 1981 SSH_SIG(ALRM); 1982 SSH_SIG(FPE); 1983 SSH_SIG(HUP); 1984 SSH_SIG(ILL); 1985 SSH_SIG(INT); 1986 SSH_SIG(KILL); 1987 SSH_SIG(PIPE); 1988 SSH_SIG(QUIT); 1989 SSH_SIG(SEGV); 1990 SSH_SIG(TERM); 1991 SSH_SIG(USR1); 1992 SSH_SIG(USR2); 1993#undef SSH_SIG 1994 return "SIG@openssh.com"; 1995} 1996 1997static void 1998session_close_x11(struct ssh *ssh, int id) 1999{ 2000 Channel *c; 2001 2002 if ((c = channel_by_id(ssh, id)) == NULL) { 2003 debug_f("x11 channel %d missing", id); 2004 } else { 2005 /* Detach X11 listener */ 2006 debug_f("detach x11 channel %d", id); 2007 channel_cancel_cleanup(ssh, id); 2008 if (c->ostate != CHAN_OUTPUT_CLOSED) 2009 chan_mark_dead(ssh, c); 2010 } 2011} 2012 2013static void 2014session_close_single_x11(struct ssh *ssh, int id, int force, void *arg) 2015{ 2016 Session *s; 2017 u_int i; 2018 2019 debug3_f("channel %d", id); 2020 channel_cancel_cleanup(ssh, id); 2021 if ((s = session_by_x11_channel(id)) == NULL) 2022 fatal_f("no x11 channel %d", id); 2023 for (i = 0; s->x11_chanids[i] != -1; i++) { 2024 debug_f("session %d: closing channel %d", 2025 s->self, s->x11_chanids[i]); 2026 /* 2027 * The channel "id" is already closing, but make sure we 2028 * close all of its siblings. 2029 */ 2030 if (s->x11_chanids[i] != id) 2031 session_close_x11(ssh, s->x11_chanids[i]); 2032 } 2033 free(s->x11_chanids); 2034 s->x11_chanids = NULL; 2035 free(s->display); 2036 s->display = NULL; 2037 free(s->auth_proto); 2038 s->auth_proto = NULL; 2039 free(s->auth_data); 2040 s->auth_data = NULL; 2041 free(s->auth_display); 2042 s->auth_display = NULL; 2043} 2044 2045static void 2046session_exit_message(struct ssh *ssh, Session *s, int status) 2047{ 2048 Channel *c; 2049 int r; 2050 char *note = NULL; 2051 2052 if ((c = channel_lookup(ssh, s->chanid)) == NULL) 2053 fatal_f("session %d: no channel %d", s->self, s->chanid); 2054 2055 if (WIFEXITED(status)) { 2056 channel_request_start(ssh, s->chanid, "exit-status", 0); 2057 if ((r = sshpkt_put_u32(ssh, WEXITSTATUS(status))) != 0 || 2058 (r = sshpkt_send(ssh)) != 0) 2059 sshpkt_fatal(ssh, r, "%s: exit reply", __func__); 2060 xasprintf(¬e, "exit %d", WEXITSTATUS(status)); 2061 } else if (WIFSIGNALED(status)) { 2062 channel_request_start(ssh, s->chanid, "exit-signal", 0); 2063 if ((r = sshpkt_put_cstring(ssh, sig2name(WTERMSIG(status)))) != 0 || 2064 (r = sshpkt_put_u8(ssh, WCOREDUMP(status)? 1 : 0)) != 0 || 2065 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2066 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2067 (r = sshpkt_send(ssh)) != 0) 2068 sshpkt_fatal(ssh, r, "%s: exit reply", __func__); 2069 xasprintf(¬e, "signal %d%s", WTERMSIG(status), 2070 WCOREDUMP(status) ? " core dumped" : ""); 2071 } else { 2072 /* Some weird exit cause. Just exit. */ 2073 ssh_packet_disconnect(ssh, "wait returned status %04x.", 2074 status); 2075 } 2076 2077 debug_f("session %d channel %d pid %ld %s", s->self, s->chanid, 2078 (long)s->pid, note == NULL ? "UNKNOWN" : note); 2079 free(note); 2080 2081 /* disconnect channel */ 2082 debug_f("release channel %d", s->chanid); 2083 2084 /* 2085 * Adjust cleanup callback attachment to send close messages when 2086 * the channel gets EOF. The session will be then be closed 2087 * by session_close_by_channel when the child sessions close their fds. 2088 */ 2089 channel_register_cleanup(ssh, c->self, session_close_by_channel, 1); 2090 2091 /* 2092 * emulate a write failure with 'chan_write_failed', nobody will be 2093 * interested in data we write. 2094 * Note that we must not call 'chan_read_failed', since there could 2095 * be some more data waiting in the pipe. 2096 */ 2097 if (c->ostate != CHAN_OUTPUT_CLOSED) 2098 chan_write_failed(ssh, c); 2099} 2100 2101void 2102session_close(struct ssh *ssh, Session *s) 2103{ 2104 u_int i; 2105 2106 verbose("Close session: user %s from %.200s port %d id %d", 2107 s->pw->pw_name, 2108 ssh_remote_ipaddr(ssh), 2109 ssh_remote_port(ssh), 2110 s->self); 2111 2112 if (s->ttyfd != -1) 2113 session_pty_cleanup(s); 2114 free(s->term); 2115 free(s->display); 2116 free(s->x11_chanids); 2117 free(s->auth_display); 2118 free(s->auth_data); 2119 free(s->auth_proto); 2120 free(s->subsys); 2121 if (s->env != NULL) { 2122 for (i = 0; i < s->num_env; i++) { 2123 free(s->env[i].name); 2124 free(s->env[i].val); 2125 } 2126 free(s->env); 2127 } 2128 session_proctitle(s); 2129 session_unused(s->self); 2130} 2131 2132void 2133session_close_by_pid(struct ssh *ssh, pid_t pid, int status) 2134{ 2135 Session *s = session_by_pid(pid); 2136 if (s == NULL) { 2137 debug_f("no session for pid %ld", (long)pid); 2138 return; 2139 } 2140 if (s->chanid != -1) 2141 session_exit_message(ssh, s, status); 2142 if (s->ttyfd != -1) 2143 session_pty_cleanup(s); 2144 s->pid = 0; 2145} 2146 2147/* 2148 * this is called when a channel dies before 2149 * the session 'child' itself dies 2150 */ 2151void 2152session_close_by_channel(struct ssh *ssh, int id, int force, void *arg) 2153{ 2154 Session *s = session_by_channel(id); 2155 u_int i; 2156 2157 if (s == NULL) { 2158 debug_f("no session for id %d", id); 2159 return; 2160 } 2161 debug_f("channel %d child %ld", id, (long)s->pid); 2162 if (s->pid != 0) { 2163 debug_f("channel %d: has child, ttyfd %d", id, s->ttyfd); 2164 /* 2165 * delay detach of session (unless this is a forced close), 2166 * but release pty, since the fd's to the child are already 2167 * closed 2168 */ 2169 if (s->ttyfd != -1) 2170 session_pty_cleanup(s); 2171 if (!force) 2172 return; 2173 } 2174 /* detach by removing callback */ 2175 channel_cancel_cleanup(ssh, s->chanid); 2176 2177 /* Close any X11 listeners associated with this session */ 2178 if (s->x11_chanids != NULL) { 2179 for (i = 0; s->x11_chanids[i] != -1; i++) { 2180 session_close_x11(ssh, s->x11_chanids[i]); 2181 s->x11_chanids[i] = -1; 2182 } 2183 } 2184 2185 s->chanid = -1; 2186 session_close(ssh, s); 2187} 2188 2189void 2190session_destroy_all(struct ssh *ssh, void (*closefunc)(Session *)) 2191{ 2192 int i; 2193 for (i = 0; i < sessions_nalloc; i++) { 2194 Session *s = &sessions[i]; 2195 if (s->used) { 2196 if (closefunc != NULL) 2197 closefunc(s); 2198 else 2199 session_close(ssh, s); 2200 } 2201 } 2202} 2203 2204static char * 2205session_tty_list(void) 2206{ 2207 static char buf[1024]; 2208 int i; 2209 buf[0] = '\0'; 2210 for (i = 0; i < sessions_nalloc; i++) { 2211 Session *s = &sessions[i]; 2212 if (s->used && s->ttyfd != -1) { 2213 if (buf[0] != '\0') 2214 strlcat(buf, ",", sizeof buf); 2215 strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf); 2216 } 2217 } 2218 if (buf[0] == '\0') 2219 strlcpy(buf, "notty", sizeof buf); 2220 return buf; 2221} 2222 2223void 2224session_proctitle(Session *s) 2225{ 2226 if (s->pw == NULL) 2227 error("no user for session %d", s->self); 2228 else 2229 setproctitle("%s@%s", s->pw->pw_name, session_tty_list()); 2230} 2231 2232int 2233session_setup_x11fwd(struct ssh *ssh, Session *s) 2234{ 2235 struct stat st; 2236 char display[512], auth_display[512]; 2237 char hostname[NI_MAXHOST]; 2238 u_int i; 2239 2240 if (!auth_opts->permit_x11_forwarding_flag) { 2241 ssh_packet_send_debug(ssh, "X11 forwarding disabled by key options."); 2242 return 0; 2243 } 2244 if (!options.x11_forwarding) { 2245 debug("X11 forwarding disabled in server configuration file."); 2246 return 0; 2247 } 2248 if (options.xauth_location == NULL || 2249 (stat(options.xauth_location, &st) == -1)) { 2250 ssh_packet_send_debug(ssh, "No xauth program; cannot forward X11."); 2251 return 0; 2252 } 2253 if (s->display != NULL) { 2254 debug("X11 display already set."); 2255 return 0; 2256 } 2257 if (x11_create_display_inet(ssh, options.x11_display_offset, 2258 options.x11_use_localhost, s->single_connection, 2259 &s->display_number, &s->x11_chanids) == -1) { 2260 debug("x11_create_display_inet failed."); 2261 return 0; 2262 } 2263 for (i = 0; s->x11_chanids[i] != -1; i++) { 2264 channel_register_cleanup(ssh, s->x11_chanids[i], 2265 session_close_single_x11, 0); 2266 } 2267 2268 /* Set up a suitable value for the DISPLAY variable. */ 2269 if (gethostname(hostname, sizeof(hostname)) == -1) 2270 fatal("gethostname: %.100s", strerror(errno)); 2271 /* 2272 * auth_display must be used as the displayname when the 2273 * authorization entry is added with xauth(1). This will be 2274 * different than the DISPLAY string for localhost displays. 2275 */ 2276 if (options.x11_use_localhost) { 2277 snprintf(display, sizeof display, "localhost:%u.%u", 2278 s->display_number, s->screen); 2279 snprintf(auth_display, sizeof auth_display, "unix:%u.%u", 2280 s->display_number, s->screen); 2281 s->display = xstrdup(display); 2282 s->auth_display = xstrdup(auth_display); 2283 } else { 2284 snprintf(display, sizeof display, "%.400s:%u.%u", hostname, 2285 s->display_number, s->screen); 2286 s->display = xstrdup(display); 2287 s->auth_display = xstrdup(display); 2288 } 2289 2290 return 1; 2291} 2292 2293static void 2294do_authenticated2(struct ssh *ssh, Authctxt *authctxt) 2295{ 2296 server_loop2(ssh, authctxt); 2297} 2298 2299void 2300do_cleanup(struct ssh *ssh, Authctxt *authctxt) 2301{ 2302 static int called = 0; 2303 2304 debug("do_cleanup"); 2305 2306 /* no cleanup if we're in the child for login shell */ 2307 if (is_child) 2308 return; 2309 2310 /* avoid double cleanup */ 2311 if (called) 2312 return; 2313 called = 1; 2314 2315 if (authctxt == NULL || !authctxt->authenticated) 2316 return; 2317#ifdef KRB5 2318 if (options.kerberos_ticket_cleanup && 2319 authctxt->krb5_ctx) 2320 krb5_cleanup_proc(authctxt); 2321#endif 2322 2323#ifdef GSSAPI 2324 if (options.gss_cleanup_creds) 2325 ssh_gssapi_cleanup_creds(); 2326#endif 2327 2328 /* remove agent socket */ 2329 auth_sock_cleanup_proc(authctxt->pw); 2330 2331 /* remove userauth info */ 2332 if (auth_info_file != NULL) { 2333 temporarily_use_uid(authctxt->pw); 2334 unlink(auth_info_file); 2335 restore_uid(); 2336 free(auth_info_file); 2337 auth_info_file = NULL; 2338 } 2339 2340 /* 2341 * Cleanup ptys/utmp only if privsep is disabled, 2342 * or if running in monitor. 2343 */ 2344 if (mm_is_monitor()) 2345 session_destroy_all(ssh, session_pty_cleanup2); 2346} 2347 2348/* Return a name for the remote host that fits inside utmp_size */ 2349 2350const char * 2351session_get_remote_name_or_ip(struct ssh *ssh, u_int utmp_size, int use_dns) 2352{ 2353 const char *remote = ""; 2354 2355 if (utmp_size > 0) 2356 remote = auth_get_canonical_hostname(ssh, use_dns); 2357 if (utmp_size == 0 || strlen(remote) > utmp_size) 2358 remote = ssh_remote_ipaddr(ssh); 2359 return remote; 2360} 2361 2362