1 /* $OpenBSD: session.c,v 1.327 2020/12/14 03:13:12 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 "compat.h" 69 #include "channels.h" 70 #include "sshkey.h" 71 #include "cipher.h" 72 #include "kex.h" 73 #include "hostfile.h" 74 #include "auth.h" 75 #include "auth-options.h" 76 #include "authfd.h" 77 #include "pathnames.h" 78 #include "log.h" 79 #include "misc.h" 80 #include "servconf.h" 81 #include "sshlogin.h" 82 #include "serverloop.h" 83 #include "canohost.h" 84 #include "session.h" 85 #ifdef GSSAPI 86 #include "ssh-gss.h" 87 #endif 88 #include "monitor_wrap.h" 89 #include "sftp.h" 90 #include "atomicio.h" 91 92 #ifdef KRB5 93 #include <kafs.h> 94 #endif 95 96 #define IS_INTERNAL_SFTP(c) \ 97 (!strncmp(c, INTERNAL_SFTP_NAME, sizeof(INTERNAL_SFTP_NAME) - 1) && \ 98 (c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\0' || \ 99 c[sizeof(INTERNAL_SFTP_NAME) - 1] == ' ' || \ 100 c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\t')) 101 102 /* func */ 103 104 Session *session_new(void); 105 void session_set_fds(struct ssh *, Session *, int, int, int, int, int); 106 void session_pty_cleanup(Session *); 107 void session_proctitle(Session *); 108 int session_setup_x11fwd(struct ssh *, Session *); 109 int do_exec_pty(struct ssh *, Session *, const char *); 110 int do_exec_no_pty(struct ssh *, Session *, const char *); 111 int do_exec(struct ssh *, Session *, const char *); 112 void do_login(struct ssh *, Session *, const char *); 113 void do_child(struct ssh *, Session *, const char *); 114 void do_motd(void); 115 int check_quietlogin(Session *, const char *); 116 117 static void do_authenticated2(struct ssh *, Authctxt *); 118 119 static int session_pty_req(struct ssh *, Session *); 120 121 /* import */ 122 extern ServerOptions options; 123 extern char *__progname; 124 extern int debug_flag; 125 extern u_int utmp_len; 126 extern int startup_pipe; 127 extern void destroy_sensitive_data(void); 128 extern struct sshbuf *loginmsg; 129 extern struct sshauthopt *auth_opts; 130 extern char *tun_fwd_ifnames; /* serverloop.c */ 131 132 /* original command from peer. */ 133 const char *original_command = NULL; 134 135 /* data */ 136 static int sessions_first_unused = -1; 137 static int sessions_nalloc = 0; 138 static Session *sessions = NULL; 139 140 #define SUBSYSTEM_NONE 0 141 #define SUBSYSTEM_EXT 1 142 #define SUBSYSTEM_INT_SFTP 2 143 #define SUBSYSTEM_INT_SFTP_ERROR 3 144 145 login_cap_t *lc; 146 147 static int is_child = 0; 148 static int in_chroot = 0; 149 150 /* File containing userauth info, if ExposeAuthInfo set */ 151 static char *auth_info_file = NULL; 152 153 /* Name and directory of socket for authentication agent forwarding. */ 154 static char *auth_sock_name = NULL; 155 static char *auth_sock_dir = NULL; 156 157 /* removes the agent forwarding socket */ 158 159 static void 160 auth_sock_cleanup_proc(struct passwd *pw) 161 { 162 if (auth_sock_name != NULL) { 163 temporarily_use_uid(pw); 164 unlink(auth_sock_name); 165 rmdir(auth_sock_dir); 166 auth_sock_name = NULL; 167 restore_uid(); 168 } 169 } 170 171 static int 172 auth_input_request_forwarding(struct ssh *ssh, struct passwd * pw) 173 { 174 Channel *nc; 175 int sock = -1; 176 177 if (auth_sock_name != NULL) { 178 error("authentication forwarding requested twice."); 179 return 0; 180 } 181 182 /* Temporarily drop privileged uid for mkdir/bind. */ 183 temporarily_use_uid(pw); 184 185 /* Allocate a buffer for the socket name, and format the name. */ 186 auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX"); 187 188 /* Create private directory for socket */ 189 if (mkdtemp(auth_sock_dir) == NULL) { 190 ssh_packet_send_debug(ssh, "Agent forwarding disabled: " 191 "mkdtemp() failed: %.100s", strerror(errno)); 192 restore_uid(); 193 free(auth_sock_dir); 194 auth_sock_dir = NULL; 195 goto authsock_err; 196 } 197 198 xasprintf(&auth_sock_name, "%s/agent.%ld", 199 auth_sock_dir, (long) getpid()); 200 201 /* Start a Unix listener on auth_sock_name. */ 202 sock = unix_listener(auth_sock_name, SSH_LISTEN_BACKLOG, 0); 203 204 /* Restore the privileged uid. */ 205 restore_uid(); 206 207 /* Check for socket/bind/listen failure. */ 208 if (sock < 0) 209 goto authsock_err; 210 211 /* Allocate a channel for the authentication agent socket. */ 212 nc = channel_new(ssh, "auth socket", 213 SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1, 214 CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 215 0, "auth socket", 1); 216 nc->path = xstrdup(auth_sock_name); 217 return 1; 218 219 authsock_err: 220 free(auth_sock_name); 221 if (auth_sock_dir != NULL) { 222 temporarily_use_uid(pw); 223 rmdir(auth_sock_dir); 224 restore_uid(); 225 free(auth_sock_dir); 226 } 227 if (sock != -1) 228 close(sock); 229 auth_sock_name = NULL; 230 auth_sock_dir = NULL; 231 return 0; 232 } 233 234 static void 235 display_loginmsg(void) 236 { 237 int r; 238 239 if (sshbuf_len(loginmsg) == 0) 240 return; 241 if ((r = sshbuf_put_u8(loginmsg, 0)) != 0) 242 fatal_fr(r, "sshbuf_put_u8"); 243 printf("%s", (char *)sshbuf_ptr(loginmsg)); 244 sshbuf_reset(loginmsg); 245 } 246 247 static void 248 prepare_auth_info_file(struct passwd *pw, struct sshbuf *info) 249 { 250 int fd = -1, success = 0; 251 252 if (!options.expose_userauth_info || info == NULL) 253 return; 254 255 temporarily_use_uid(pw); 256 auth_info_file = xstrdup("/tmp/sshauth.XXXXXXXXXXXXXXX"); 257 if ((fd = mkstemp(auth_info_file)) == -1) { 258 error_f("mkstemp: %s", strerror(errno)); 259 goto out; 260 } 261 if (atomicio(vwrite, fd, sshbuf_mutable_ptr(info), 262 sshbuf_len(info)) != sshbuf_len(info)) { 263 error_f("write: %s", strerror(errno)); 264 goto out; 265 } 266 if (close(fd) != 0) { 267 error_f("close: %s", strerror(errno)); 268 goto out; 269 } 270 success = 1; 271 out: 272 if (!success) { 273 if (fd != -1) 274 close(fd); 275 free(auth_info_file); 276 auth_info_file = NULL; 277 } 278 restore_uid(); 279 } 280 281 static void 282 set_fwdpermit_from_authopts(struct ssh *ssh, const struct sshauthopt *opts) 283 { 284 char *tmp, *cp, *host; 285 int port; 286 size_t i; 287 288 if ((options.allow_tcp_forwarding & FORWARD_LOCAL) != 0) { 289 channel_clear_permission(ssh, FORWARD_USER, FORWARD_LOCAL); 290 for (i = 0; i < auth_opts->npermitopen; i++) { 291 tmp = cp = xstrdup(auth_opts->permitopen[i]); 292 /* This shouldn't fail as it has already been checked */ 293 if ((host = hpdelim(&cp)) == NULL) 294 fatal_f("internal error: hpdelim"); 295 host = cleanhostname(host); 296 if (cp == NULL || (port = permitopen_port(cp)) < 0) 297 fatal_f("internal error: permitopen port"); 298 channel_add_permission(ssh, 299 FORWARD_USER, FORWARD_LOCAL, host, port); 300 free(tmp); 301 } 302 } 303 if ((options.allow_tcp_forwarding & FORWARD_REMOTE) != 0) { 304 channel_clear_permission(ssh, FORWARD_USER, FORWARD_REMOTE); 305 for (i = 0; i < auth_opts->npermitlisten; i++) { 306 tmp = cp = xstrdup(auth_opts->permitlisten[i]); 307 /* This shouldn't fail as it has already been checked */ 308 if ((host = hpdelim(&cp)) == NULL) 309 fatal_f("internal error: hpdelim"); 310 host = cleanhostname(host); 311 if (cp == NULL || (port = permitopen_port(cp)) < 0) 312 fatal_f("internal error: permitlisten port"); 313 channel_add_permission(ssh, 314 FORWARD_USER, FORWARD_REMOTE, host, port); 315 free(tmp); 316 } 317 } 318 } 319 320 void 321 do_authenticated(struct ssh *ssh, Authctxt *authctxt) 322 { 323 setproctitle("%s", authctxt->pw->pw_name); 324 325 auth_log_authopts("active", auth_opts, 0); 326 327 /* setup the channel layer */ 328 /* XXX - streamlocal? */ 329 set_fwdpermit_from_authopts(ssh, auth_opts); 330 331 if (!auth_opts->permit_port_forwarding_flag || 332 options.disable_forwarding) { 333 channel_disable_admin(ssh, FORWARD_LOCAL); 334 channel_disable_admin(ssh, FORWARD_REMOTE); 335 } else { 336 if ((options.allow_tcp_forwarding & FORWARD_LOCAL) == 0) 337 channel_disable_admin(ssh, FORWARD_LOCAL); 338 else 339 channel_permit_all(ssh, FORWARD_LOCAL); 340 if ((options.allow_tcp_forwarding & FORWARD_REMOTE) == 0) 341 channel_disable_admin(ssh, FORWARD_REMOTE); 342 else 343 channel_permit_all(ssh, FORWARD_REMOTE); 344 } 345 auth_debug_send(ssh); 346 347 prepare_auth_info_file(authctxt->pw, authctxt->session_info); 348 349 do_authenticated2(ssh, authctxt); 350 351 do_cleanup(ssh, authctxt); 352 } 353 354 /* Check untrusted xauth strings for metacharacters */ 355 static int 356 xauth_valid_string(const char *s) 357 { 358 size_t i; 359 360 for (i = 0; s[i] != '\0'; i++) { 361 if (!isalnum((u_char)s[i]) && 362 s[i] != '.' && s[i] != ':' && s[i] != '/' && 363 s[i] != '-' && s[i] != '_') 364 return 0; 365 } 366 return 1; 367 } 368 369 #define USE_PIPES 1 370 /* 371 * This is called to fork and execute a command when we have no tty. This 372 * will call do_child from the child, and server_loop from the parent after 373 * setting up file descriptors and such. 374 */ 375 int 376 do_exec_no_pty(struct ssh *ssh, Session *s, const char *command) 377 { 378 pid_t pid; 379 #ifdef USE_PIPES 380 int pin[2], pout[2], perr[2]; 381 382 if (s == NULL) 383 fatal("do_exec_no_pty: no session"); 384 385 /* Allocate pipes for communicating with the program. */ 386 if (pipe(pin) == -1) { 387 error_f("pipe in: %.100s", strerror(errno)); 388 return -1; 389 } 390 if (pipe(pout) == -1) { 391 error_f("pipe out: %.100s", strerror(errno)); 392 close(pin[0]); 393 close(pin[1]); 394 return -1; 395 } 396 if (pipe(perr) == -1) { 397 error_f("pipe err: %.100s", strerror(errno)); 398 close(pin[0]); 399 close(pin[1]); 400 close(pout[0]); 401 close(pout[1]); 402 return -1; 403 } 404 #else 405 int inout[2], err[2]; 406 407 if (s == NULL) 408 fatal("do_exec_no_pty: no session"); 409 410 /* Uses socket pairs to communicate with the program. */ 411 if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) == -1) { 412 error_f("socketpair #1: %.100s", strerror(errno)); 413 return -1; 414 } 415 if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) == -1) { 416 error_f("socketpair #2: %.100s", strerror(errno)); 417 close(inout[0]); 418 close(inout[1]); 419 return -1; 420 } 421 #endif 422 423 session_proctitle(s); 424 425 /* Fork the child. */ 426 switch ((pid = fork())) { 427 case -1: 428 error_f("fork: %.100s", strerror(errno)); 429 #ifdef USE_PIPES 430 close(pin[0]); 431 close(pin[1]); 432 close(pout[0]); 433 close(pout[1]); 434 close(perr[0]); 435 close(perr[1]); 436 #else 437 close(inout[0]); 438 close(inout[1]); 439 close(err[0]); 440 close(err[1]); 441 #endif 442 return -1; 443 case 0: 444 is_child = 1; 445 446 /* 447 * Create a new session and process group since the 4.4BSD 448 * setlogin() affects the entire process group. 449 */ 450 if (setsid() == -1) 451 error("setsid failed: %.100s", strerror(errno)); 452 453 #ifdef USE_PIPES 454 /* 455 * Redirect stdin. We close the parent side of the socket 456 * pair, and make the child side the standard input. 457 */ 458 close(pin[1]); 459 if (dup2(pin[0], 0) == -1) 460 perror("dup2 stdin"); 461 close(pin[0]); 462 463 /* Redirect stdout. */ 464 close(pout[0]); 465 if (dup2(pout[1], 1) == -1) 466 perror("dup2 stdout"); 467 close(pout[1]); 468 469 /* Redirect stderr. */ 470 close(perr[0]); 471 if (dup2(perr[1], 2) == -1) 472 perror("dup2 stderr"); 473 close(perr[1]); 474 #else 475 /* 476 * Redirect stdin, stdout, and stderr. Stdin and stdout will 477 * use the same socket, as some programs (particularly rdist) 478 * seem to depend on it. 479 */ 480 close(inout[1]); 481 close(err[1]); 482 if (dup2(inout[0], 0) == -1) /* stdin */ 483 perror("dup2 stdin"); 484 if (dup2(inout[0], 1) == -1) /* stdout (same as stdin) */ 485 perror("dup2 stdout"); 486 close(inout[0]); 487 if (dup2(err[0], 2) == -1) /* stderr */ 488 perror("dup2 stderr"); 489 close(err[0]); 490 #endif 491 492 /* Do processing for the child (exec command etc). */ 493 do_child(ssh, s, command); 494 /* NOTREACHED */ 495 default: 496 break; 497 } 498 499 s->pid = pid; 500 /* Set interactive/non-interactive mode. */ 501 ssh_packet_set_interactive(ssh, s->display != NULL, 502 options.ip_qos_interactive, options.ip_qos_bulk); 503 504 #ifdef USE_PIPES 505 /* We are the parent. Close the child sides of the pipes. */ 506 close(pin[0]); 507 close(pout[1]); 508 close(perr[1]); 509 510 session_set_fds(ssh, s, pin[1], pout[0], perr[0], 511 s->is_subsystem, 0); 512 #else 513 /* We are the parent. Close the child sides of the socket pairs. */ 514 close(inout[0]); 515 close(err[0]); 516 517 /* 518 * Enter the interactive session. Note: server_loop must be able to 519 * handle the case that fdin and fdout are the same. 520 */ 521 session_set_fds(ssh, s, inout[1], inout[1], err[1], 522 s->is_subsystem, 0); 523 #endif 524 return 0; 525 } 526 527 /* 528 * This is called to fork and execute a command when we have a tty. This 529 * will call do_child from the child, and server_loop from the parent after 530 * setting up file descriptors, controlling tty, updating wtmp, utmp, 531 * lastlog, and other such operations. 532 */ 533 int 534 do_exec_pty(struct ssh *ssh, Session *s, const char *command) 535 { 536 int fdout, ptyfd, ttyfd, ptymaster; 537 pid_t pid; 538 539 if (s == NULL) 540 fatal("do_exec_pty: no session"); 541 ptyfd = s->ptyfd; 542 ttyfd = s->ttyfd; 543 544 /* 545 * Create another descriptor of the pty master side for use as the 546 * standard input. We could use the original descriptor, but this 547 * simplifies code in server_loop. The descriptor is bidirectional. 548 * Do this before forking (and cleanup in the child) so as to 549 * detect and gracefully fail out-of-fd conditions. 550 */ 551 if ((fdout = dup(ptyfd)) == -1) { 552 error_f("dup #1: %s", strerror(errno)); 553 close(ttyfd); 554 close(ptyfd); 555 return -1; 556 } 557 /* we keep a reference to the pty master */ 558 if ((ptymaster = dup(ptyfd)) == -1) { 559 error_f("dup #2: %s", strerror(errno)); 560 close(ttyfd); 561 close(ptyfd); 562 close(fdout); 563 return -1; 564 } 565 566 /* Fork the child. */ 567 switch ((pid = fork())) { 568 case -1: 569 error_f("fork: %.100s", strerror(errno)); 570 close(fdout); 571 close(ptymaster); 572 close(ttyfd); 573 close(ptyfd); 574 return -1; 575 case 0: 576 is_child = 1; 577 578 close(fdout); 579 close(ptymaster); 580 581 /* Close the master side of the pseudo tty. */ 582 close(ptyfd); 583 584 /* Make the pseudo tty our controlling tty. */ 585 pty_make_controlling_tty(&ttyfd, s->tty); 586 587 /* Redirect stdin/stdout/stderr from the pseudo tty. */ 588 if (dup2(ttyfd, 0) == -1) 589 error("dup2 stdin: %s", strerror(errno)); 590 if (dup2(ttyfd, 1) == -1) 591 error("dup2 stdout: %s", strerror(errno)); 592 if (dup2(ttyfd, 2) == -1) 593 error("dup2 stderr: %s", strerror(errno)); 594 595 /* Close the extra descriptor for the pseudo tty. */ 596 close(ttyfd); 597 598 /* record login, etc. similar to login(1) */ 599 do_login(ssh, s, command); 600 601 /* 602 * Do common processing for the child, such as execing 603 * the command. 604 */ 605 do_child(ssh, s, command); 606 /* NOTREACHED */ 607 default: 608 break; 609 } 610 s->pid = pid; 611 612 /* Parent. Close the slave side of the pseudo tty. */ 613 close(ttyfd); 614 615 /* Enter interactive session. */ 616 s->ptymaster = ptymaster; 617 ssh_packet_set_interactive(ssh, 1, 618 options.ip_qos_interactive, options.ip_qos_bulk); 619 session_set_fds(ssh, s, ptyfd, fdout, -1, 1, 1); 620 return 0; 621 } 622 623 /* 624 * This is called to fork and execute a command. If another command is 625 * to be forced, execute that instead. 626 */ 627 int 628 do_exec(struct ssh *ssh, Session *s, const char *command) 629 { 630 int ret; 631 const char *forced = NULL, *tty = NULL; 632 char session_type[1024]; 633 634 if (options.adm_forced_command) { 635 original_command = command; 636 command = options.adm_forced_command; 637 forced = "(config)"; 638 } else if (auth_opts->force_command != NULL) { 639 original_command = command; 640 command = auth_opts->force_command; 641 forced = "(key-option)"; 642 } 643 s->forced = 0; 644 if (forced != NULL) { 645 s->forced = 1; 646 if (IS_INTERNAL_SFTP(command)) { 647 s->is_subsystem = s->is_subsystem ? 648 SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR; 649 } else if (s->is_subsystem) 650 s->is_subsystem = SUBSYSTEM_EXT; 651 snprintf(session_type, sizeof(session_type), 652 "forced-command %s '%.900s'", forced, command); 653 } else if (s->is_subsystem) { 654 snprintf(session_type, sizeof(session_type), 655 "subsystem '%.900s'", s->subsys); 656 } else if (command == NULL) { 657 snprintf(session_type, sizeof(session_type), "shell"); 658 } else { 659 /* NB. we don't log unforced commands to preserve privacy */ 660 snprintf(session_type, sizeof(session_type), "command"); 661 } 662 663 if (s->ttyfd != -1) { 664 tty = s->tty; 665 if (strncmp(tty, "/dev/", 5) == 0) 666 tty += 5; 667 } 668 669 verbose("Starting session: %s%s%s for %s from %.200s port %d id %d", 670 session_type, 671 tty == NULL ? "" : " on ", 672 tty == NULL ? "" : tty, 673 s->pw->pw_name, 674 ssh_remote_ipaddr(ssh), 675 ssh_remote_port(ssh), 676 s->self); 677 678 #ifdef GSSAPI 679 if (options.gss_authentication) { 680 temporarily_use_uid(s->pw); 681 ssh_gssapi_storecreds(); 682 restore_uid(); 683 } 684 #endif 685 if (s->ttyfd != -1) 686 ret = do_exec_pty(ssh, s, command); 687 else 688 ret = do_exec_no_pty(ssh, s, command); 689 690 original_command = NULL; 691 692 /* 693 * Clear loginmsg: it's the child's responsibility to display 694 * it to the user, otherwise multiple sessions may accumulate 695 * multiple copies of the login messages. 696 */ 697 sshbuf_reset(loginmsg); 698 699 return ret; 700 } 701 702 703 /* administrative, login(1)-like work */ 704 void 705 do_login(struct ssh *ssh, Session *s, const char *command) 706 { 707 socklen_t fromlen; 708 struct sockaddr_storage from; 709 struct passwd * pw = s->pw; 710 pid_t pid = getpid(); 711 712 /* 713 * Get IP address of client. If the connection is not a socket, let 714 * the address be 0.0.0.0. 715 */ 716 memset(&from, 0, sizeof(from)); 717 fromlen = sizeof(from); 718 if (ssh_packet_connection_is_on_socket(ssh)) { 719 if (getpeername(ssh_packet_get_connection_in(ssh), 720 (struct sockaddr *)&from, &fromlen) == -1) { 721 debug("getpeername: %.100s", strerror(errno)); 722 cleanup_exit(255); 723 } 724 } 725 726 /* Record that there was a login on that tty from the remote host. */ 727 if (!use_privsep) 728 record_login(pid, s->tty, pw->pw_name, pw->pw_uid, 729 session_get_remote_name_or_ip(ssh, utmp_len, 730 options.use_dns), 731 (struct sockaddr *)&from, fromlen); 732 733 if (check_quietlogin(s, command)) 734 return; 735 736 display_loginmsg(); 737 738 do_motd(); 739 } 740 741 /* 742 * Display the message of the day. 743 */ 744 void 745 do_motd(void) 746 { 747 FILE *f; 748 char buf[256]; 749 750 if (options.print_motd) { 751 f = fopen(login_getcapstr(lc, "welcome", "/etc/motd", 752 "/etc/motd"), "r"); 753 if (f) { 754 while (fgets(buf, sizeof(buf), f)) 755 fputs(buf, stdout); 756 fclose(f); 757 } 758 } 759 } 760 761 762 /* 763 * Check for quiet login, either .hushlogin or command given. 764 */ 765 int 766 check_quietlogin(Session *s, const char *command) 767 { 768 char buf[256]; 769 struct passwd *pw = s->pw; 770 struct stat st; 771 772 /* Return 1 if .hushlogin exists or a command given. */ 773 if (command != NULL) 774 return 1; 775 snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir); 776 if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0) 777 return 1; 778 return 0; 779 } 780 781 /* 782 * Reads environment variables from the given file and adds/overrides them 783 * into the environment. If the file does not exist, this does nothing. 784 * Otherwise, it must consist of empty lines, comments (line starts with '#') 785 * and assignments of the form name=value. No other forms are allowed. 786 * If allowlist is not NULL, then it is interpreted as a pattern list and 787 * only variable names that match it will be accepted. 788 */ 789 static void 790 read_environment_file(char ***env, u_int *envsize, 791 const char *filename, const char *allowlist) 792 { 793 FILE *f; 794 char *line = NULL, *cp, *value; 795 size_t linesize = 0; 796 u_int lineno = 0; 797 798 f = fopen(filename, "r"); 799 if (!f) 800 return; 801 802 while (getline(&line, &linesize, f) != -1) { 803 if (++lineno > 1000) 804 fatal("Too many lines in environment file %s", filename); 805 for (cp = line; *cp == ' ' || *cp == '\t'; cp++) 806 ; 807 if (!*cp || *cp == '#' || *cp == '\n') 808 continue; 809 810 cp[strcspn(cp, "\n")] = '\0'; 811 812 value = strchr(cp, '='); 813 if (value == NULL) { 814 fprintf(stderr, "Bad line %u in %.100s\n", lineno, 815 filename); 816 continue; 817 } 818 /* 819 * Replace the equals sign by nul, and advance value to 820 * the value string. 821 */ 822 *value = '\0'; 823 value++; 824 if (allowlist != NULL && 825 match_pattern_list(cp, allowlist, 0) != 1) 826 continue; 827 child_set_env(env, envsize, cp, value); 828 } 829 free(line); 830 fclose(f); 831 } 832 833 static char ** 834 do_setup_env(struct ssh *ssh, Session *s, const char *shell) 835 { 836 char buf[256]; 837 size_t n; 838 u_int i, envsize; 839 char *ocp, *cp, *value, **env, *laddr; 840 struct passwd *pw = s->pw; 841 842 /* Initialize the environment. */ 843 envsize = 100; 844 env = xcalloc(envsize, sizeof(char *)); 845 env[0] = NULL; 846 847 #ifdef GSSAPI 848 /* Allow any GSSAPI methods that we've used to alter 849 * the child's environment as they see fit 850 */ 851 ssh_gssapi_do_child(&env, &envsize); 852 #endif 853 854 /* Set basic environment. */ 855 for (i = 0; i < s->num_env; i++) 856 child_set_env(&env, &envsize, s->env[i].name, s->env[i].val); 857 858 child_set_env(&env, &envsize, "USER", pw->pw_name); 859 child_set_env(&env, &envsize, "LOGNAME", pw->pw_name); 860 child_set_env(&env, &envsize, "HOME", pw->pw_dir); 861 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0) 862 child_set_env(&env, &envsize, "PATH", _PATH_STDPATH); 863 else 864 child_set_env(&env, &envsize, "PATH", getenv("PATH")); 865 866 snprintf(buf, sizeof buf, "%.200s/%.50s", _PATH_MAILDIR, pw->pw_name); 867 child_set_env(&env, &envsize, "MAIL", buf); 868 869 /* Normal systems set SHELL by default. */ 870 child_set_env(&env, &envsize, "SHELL", shell); 871 872 if (getenv("TZ")) 873 child_set_env(&env, &envsize, "TZ", getenv("TZ")); 874 if (s->term) 875 child_set_env(&env, &envsize, "TERM", s->term); 876 if (s->display) 877 child_set_env(&env, &envsize, "DISPLAY", s->display); 878 #ifdef KRB5 879 if (s->authctxt->krb5_ticket_file) 880 child_set_env(&env, &envsize, "KRB5CCNAME", 881 s->authctxt->krb5_ticket_file); 882 #endif 883 if (auth_sock_name != NULL) 884 child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME, 885 auth_sock_name); 886 887 888 /* Set custom environment options from pubkey authentication. */ 889 if (options.permit_user_env) { 890 for (n = 0 ; n < auth_opts->nenv; n++) { 891 ocp = xstrdup(auth_opts->env[n]); 892 cp = strchr(ocp, '='); 893 if (cp != NULL) { 894 *cp = '\0'; 895 /* Apply PermitUserEnvironment allowlist */ 896 if (options.permit_user_env_allowlist == NULL || 897 match_pattern_list(ocp, 898 options.permit_user_env_allowlist, 0) == 1) 899 child_set_env(&env, &envsize, 900 ocp, cp + 1); 901 } 902 free(ocp); 903 } 904 } 905 906 /* read $HOME/.ssh/environment. */ 907 if (options.permit_user_env) { 908 snprintf(buf, sizeof buf, "%.200s/%s/environment", 909 pw->pw_dir, _PATH_SSH_USER_DIR); 910 read_environment_file(&env, &envsize, buf, 911 options.permit_user_env_allowlist); 912 } 913 914 /* Environment specified by admin */ 915 for (i = 0; i < options.num_setenv; i++) { 916 cp = xstrdup(options.setenv[i]); 917 if ((value = strchr(cp, '=')) == NULL) { 918 /* shouldn't happen; vars are checked in servconf.c */ 919 fatal("Invalid config SetEnv: %s", options.setenv[i]); 920 } 921 *value++ = '\0'; 922 child_set_env(&env, &envsize, cp, value); 923 } 924 925 /* SSH_CLIENT deprecated */ 926 snprintf(buf, sizeof buf, "%.50s %d %d", 927 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 928 ssh_local_port(ssh)); 929 child_set_env(&env, &envsize, "SSH_CLIENT", buf); 930 931 laddr = get_local_ipaddr(ssh_packet_get_connection_in(ssh)); 932 snprintf(buf, sizeof buf, "%.50s %d %.50s %d", 933 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), 934 laddr, ssh_local_port(ssh)); 935 free(laddr); 936 child_set_env(&env, &envsize, "SSH_CONNECTION", buf); 937 938 if (tun_fwd_ifnames != NULL) 939 child_set_env(&env, &envsize, "SSH_TUNNEL", tun_fwd_ifnames); 940 if (auth_info_file != NULL) 941 child_set_env(&env, &envsize, "SSH_USER_AUTH", auth_info_file); 942 if (s->ttyfd != -1) 943 child_set_env(&env, &envsize, "SSH_TTY", s->tty); 944 if (original_command) 945 child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND", 946 original_command); 947 948 if (debug_flag) { 949 /* dump the environment */ 950 fprintf(stderr, "Environment:\n"); 951 for (i = 0; env[i]; i++) 952 fprintf(stderr, " %.200s\n", env[i]); 953 } 954 return env; 955 } 956 957 /* 958 * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found 959 * first in this order). 960 */ 961 static void 962 do_rc_files(struct ssh *ssh, Session *s, const char *shell) 963 { 964 FILE *f = NULL; 965 char *cmd = NULL, *user_rc = NULL; 966 int do_xauth; 967 struct stat st; 968 969 do_xauth = 970 s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL; 971 xasprintf(&user_rc, "%s/%s", s->pw->pw_dir, _PATH_SSH_USER_RC); 972 973 /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */ 974 if (!s->is_subsystem && options.adm_forced_command == NULL && 975 auth_opts->permit_user_rc && options.permit_user_rc && 976 stat(user_rc, &st) >= 0) { 977 if (xasprintf(&cmd, "%s -c '%s %s'", shell, _PATH_BSHELL, 978 user_rc) == -1) 979 fatal_f("xasprintf: %s", strerror(errno)); 980 if (debug_flag) 981 fprintf(stderr, "Running %s\n", cmd); 982 f = popen(cmd, "w"); 983 if (f) { 984 if (do_xauth) 985 fprintf(f, "%s %s\n", s->auth_proto, 986 s->auth_data); 987 pclose(f); 988 } else 989 fprintf(stderr, "Could not run %s\n", 990 user_rc); 991 } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) { 992 if (debug_flag) 993 fprintf(stderr, "Running %s %s\n", _PATH_BSHELL, 994 _PATH_SSH_SYSTEM_RC); 995 f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w"); 996 if (f) { 997 if (do_xauth) 998 fprintf(f, "%s %s\n", s->auth_proto, 999 s->auth_data); 1000 pclose(f); 1001 } else 1002 fprintf(stderr, "Could not run %s\n", 1003 _PATH_SSH_SYSTEM_RC); 1004 } else if (do_xauth && options.xauth_location != NULL) { 1005 /* Add authority data to .Xauthority if appropriate. */ 1006 if (debug_flag) { 1007 fprintf(stderr, 1008 "Running %.500s remove %.100s\n", 1009 options.xauth_location, s->auth_display); 1010 fprintf(stderr, 1011 "%.500s add %.100s %.100s %.100s\n", 1012 options.xauth_location, s->auth_display, 1013 s->auth_proto, s->auth_data); 1014 } 1015 if (xasprintf(&cmd, "%s -q -", options.xauth_location) == -1) 1016 fatal_f("xasprintf: %s", strerror(errno)); 1017 f = popen(cmd, "w"); 1018 if (f) { 1019 fprintf(f, "remove %s\n", 1020 s->auth_display); 1021 fprintf(f, "add %s %s %s\n", 1022 s->auth_display, s->auth_proto, 1023 s->auth_data); 1024 pclose(f); 1025 } else { 1026 fprintf(stderr, "Could not run %s\n", 1027 cmd); 1028 } 1029 } 1030 free(cmd); 1031 free(user_rc); 1032 } 1033 1034 static void 1035 do_nologin(struct passwd *pw) 1036 { 1037 FILE *f = NULL; 1038 char buf[1024], *nl, *def_nl = _PATH_NOLOGIN; 1039 struct stat sb; 1040 1041 if (login_getcapbool(lc, "ignorenologin", 0) || pw->pw_uid == 0) 1042 return; 1043 nl = login_getcapstr(lc, "nologin", def_nl, def_nl); 1044 1045 if (stat(nl, &sb) == -1) { 1046 if (nl != def_nl) 1047 free(nl); 1048 return; 1049 } 1050 1051 /* /etc/nologin exists. Print its contents if we can and exit. */ 1052 logit("User %.100s not allowed because %s exists", pw->pw_name, nl); 1053 if ((f = fopen(nl, "r")) != NULL) { 1054 while (fgets(buf, sizeof(buf), f)) 1055 fputs(buf, stderr); 1056 fclose(f); 1057 } 1058 exit(254); 1059 } 1060 1061 /* 1062 * Chroot into a directory after checking it for safety: all path components 1063 * must be root-owned directories with strict permissions. 1064 */ 1065 static void 1066 safely_chroot(const char *path, uid_t uid) 1067 { 1068 const char *cp; 1069 char component[PATH_MAX]; 1070 struct stat st; 1071 1072 if (!path_absolute(path)) 1073 fatal("chroot path does not begin at root"); 1074 if (strlen(path) >= sizeof(component)) 1075 fatal("chroot path too long"); 1076 1077 /* 1078 * Descend the path, checking that each component is a 1079 * root-owned directory with strict permissions. 1080 */ 1081 for (cp = path; cp != NULL;) { 1082 if ((cp = strchr(cp, '/')) == NULL) 1083 strlcpy(component, path, sizeof(component)); 1084 else { 1085 cp++; 1086 memcpy(component, path, cp - path); 1087 component[cp - path] = '\0'; 1088 } 1089 1090 debug3_f("checking '%s'", component); 1091 1092 if (stat(component, &st) != 0) 1093 fatal_f("stat(\"%s\"): %s", 1094 component, strerror(errno)); 1095 if (st.st_uid != 0 || (st.st_mode & 022) != 0) 1096 fatal("bad ownership or modes for chroot " 1097 "directory %s\"%s\"", 1098 cp == NULL ? "" : "component ", component); 1099 if (!S_ISDIR(st.st_mode)) 1100 fatal("chroot path %s\"%s\" is not a directory", 1101 cp == NULL ? "" : "component ", component); 1102 1103 } 1104 1105 if (chdir(path) == -1) 1106 fatal("Unable to chdir to chroot path \"%s\": " 1107 "%s", path, strerror(errno)); 1108 if (chroot(path) == -1) 1109 fatal("chroot(\"%s\"): %s", path, strerror(errno)); 1110 if (chdir("/") == -1) 1111 fatal_f("chdir(/) after chroot: %s", strerror(errno)); 1112 verbose("Changed root directory to \"%s\"", path); 1113 } 1114 1115 /* Set login name, uid, gid, and groups. */ 1116 void 1117 do_setusercontext(struct passwd *pw) 1118 { 1119 char uidstr[32], *chroot_path, *tmp; 1120 1121 if (getuid() == 0 || geteuid() == 0) { 1122 /* Prepare groups */ 1123 if (setusercontext(lc, pw, pw->pw_uid, 1124 (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) { 1125 perror("unable to set user context"); 1126 exit(1); 1127 } 1128 1129 if (!in_chroot && options.chroot_directory != NULL && 1130 strcasecmp(options.chroot_directory, "none") != 0) { 1131 tmp = tilde_expand_filename(options.chroot_directory, 1132 pw->pw_uid); 1133 snprintf(uidstr, sizeof(uidstr), "%llu", 1134 (unsigned long long)pw->pw_uid); 1135 chroot_path = percent_expand(tmp, "h", pw->pw_dir, 1136 "u", pw->pw_name, "U", uidstr, (char *)NULL); 1137 safely_chroot(chroot_path, pw->pw_uid); 1138 free(tmp); 1139 free(chroot_path); 1140 /* Make sure we don't attempt to chroot again */ 1141 free(options.chroot_directory); 1142 options.chroot_directory = NULL; 1143 in_chroot = 1; 1144 } 1145 1146 /* Set UID */ 1147 if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) { 1148 perror("unable to set user context (setuser)"); 1149 exit(1); 1150 } 1151 } else if (options.chroot_directory != NULL && 1152 strcasecmp(options.chroot_directory, "none") != 0) { 1153 fatal("server lacks privileges to chroot to ChrootDirectory"); 1154 } 1155 1156 if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid) 1157 fatal("Failed to set uids to %u.", (u_int) pw->pw_uid); 1158 } 1159 1160 static void 1161 do_pwchange(Session *s) 1162 { 1163 fflush(NULL); 1164 fprintf(stderr, "WARNING: Your password has expired.\n"); 1165 if (s->ttyfd != -1) { 1166 fprintf(stderr, 1167 "You must change your password now and login again!\n"); 1168 execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL); 1169 perror("passwd"); 1170 } else { 1171 fprintf(stderr, 1172 "Password change required but no TTY available.\n"); 1173 } 1174 exit(1); 1175 } 1176 1177 static void 1178 child_close_fds(struct ssh *ssh) 1179 { 1180 extern int auth_sock; 1181 1182 if (auth_sock != -1) { 1183 close(auth_sock); 1184 auth_sock = -1; 1185 } 1186 1187 if (ssh_packet_get_connection_in(ssh) == 1188 ssh_packet_get_connection_out(ssh)) 1189 close(ssh_packet_get_connection_in(ssh)); 1190 else { 1191 close(ssh_packet_get_connection_in(ssh)); 1192 close(ssh_packet_get_connection_out(ssh)); 1193 } 1194 /* 1195 * Close all descriptors related to channels. They will still remain 1196 * open in the parent. 1197 */ 1198 /* XXX better use close-on-exec? -markus */ 1199 channel_close_all(ssh); 1200 1201 /* 1202 * Close any extra file descriptors. Note that there may still be 1203 * descriptors left by system functions. They will be closed later. 1204 */ 1205 endpwent(); 1206 1207 /* Stop directing logs to a high-numbered fd before we close it */ 1208 log_redirect_stderr_to(NULL); 1209 1210 /* 1211 * Close any extra open file descriptors so that we don't have them 1212 * hanging around in clients. Note that we want to do this after 1213 * initgroups, because at least on Solaris 2.3 it leaves file 1214 * descriptors open. 1215 */ 1216 closefrom(STDERR_FILENO + 1); 1217 } 1218 1219 /* 1220 * Performs common processing for the child, such as setting up the 1221 * environment, closing extra file descriptors, setting the user and group 1222 * ids, and executing the command or shell. 1223 */ 1224 #define ARGV_MAX 10 1225 void 1226 do_child(struct ssh *ssh, Session *s, const char *command) 1227 { 1228 extern char **environ; 1229 char **env, *argv[ARGV_MAX], remote_id[512]; 1230 const char *shell, *shell0; 1231 struct passwd *pw = s->pw; 1232 int r = 0; 1233 1234 sshpkt_fmt_connection_id(ssh, remote_id, sizeof(remote_id)); 1235 1236 /* remove hostkey from the child's memory */ 1237 destroy_sensitive_data(); 1238 ssh_packet_clear_keys(ssh); 1239 1240 /* Force a password change */ 1241 if (s->authctxt->force_pwchange) { 1242 do_setusercontext(pw); 1243 child_close_fds(ssh); 1244 do_pwchange(s); 1245 exit(1); 1246 } 1247 1248 /* 1249 * Login(1) does this as well, and it needs uid 0 for the "-h" 1250 * switch, so we let login(1) to this for us. 1251 */ 1252 do_nologin(pw); 1253 do_setusercontext(pw); 1254 1255 /* 1256 * Get the shell from the password data. An empty shell field is 1257 * legal, and means /bin/sh. 1258 */ 1259 shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell; 1260 1261 /* 1262 * Make sure $SHELL points to the shell from the password file, 1263 * even if shell is overridden from login.conf 1264 */ 1265 env = do_setup_env(ssh, s, shell); 1266 1267 shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell); 1268 1269 /* 1270 * Close the connection descriptors; note that this is the child, and 1271 * the server will still have the socket open, and it is important 1272 * that we do not shutdown it. Note that the descriptors cannot be 1273 * closed before building the environment, as we call 1274 * ssh_remote_ipaddr there. 1275 */ 1276 child_close_fds(ssh); 1277 1278 /* 1279 * Must take new environment into use so that .ssh/rc, 1280 * /etc/ssh/sshrc and xauth are run in the proper environment. 1281 */ 1282 environ = env; 1283 1284 #ifdef KRB5 1285 /* 1286 * At this point, we check to see if AFS is active and if we have 1287 * a valid Kerberos 5 TGT. If so, it seems like a good idea to see 1288 * if we can (and need to) extend the ticket into an AFS token. If 1289 * we don't do this, we run into potential problems if the user's 1290 * home directory is in AFS and it's not world-readable. 1291 */ 1292 1293 if (options.kerberos_get_afs_token && k_hasafs() && 1294 (s->authctxt->krb5_ctx != NULL)) { 1295 char cell[64]; 1296 1297 debug("Getting AFS token"); 1298 1299 k_setpag(); 1300 1301 if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0) 1302 krb5_afslog(s->authctxt->krb5_ctx, 1303 s->authctxt->krb5_fwd_ccache, cell, NULL); 1304 1305 krb5_afslog_home(s->authctxt->krb5_ctx, 1306 s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir); 1307 } 1308 #endif 1309 1310 /* Change current directory to the user's home directory. */ 1311 if (chdir(pw->pw_dir) == -1) { 1312 /* Suppress missing homedir warning for chroot case */ 1313 r = login_getcapbool(lc, "requirehome", 0); 1314 if (r || !in_chroot) { 1315 fprintf(stderr, "Could not chdir to home " 1316 "directory %s: %s\n", pw->pw_dir, 1317 strerror(errno)); 1318 } 1319 if (r) 1320 exit(1); 1321 } 1322 1323 closefrom(STDERR_FILENO + 1); 1324 1325 do_rc_files(ssh, s, shell); 1326 1327 /* restore SIGPIPE for child */ 1328 ssh_signal(SIGPIPE, SIG_DFL); 1329 1330 if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) { 1331 error("Connection from %s: refusing non-sftp session", 1332 remote_id); 1333 printf("This service allows sftp connections only.\n"); 1334 fflush(NULL); 1335 exit(1); 1336 } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) { 1337 extern int optind, optreset; 1338 int i; 1339 char *p, *args; 1340 1341 setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME); 1342 args = xstrdup(command ? command : "sftp-server"); 1343 for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " "))) 1344 if (i < ARGV_MAX - 1) 1345 argv[i++] = p; 1346 argv[i] = NULL; 1347 optind = optreset = 1; 1348 __progname = argv[0]; 1349 exit(sftp_server_main(i, argv, s->pw)); 1350 } 1351 1352 fflush(NULL); 1353 1354 /* Get the last component of the shell name. */ 1355 if ((shell0 = strrchr(shell, '/')) != NULL) 1356 shell0++; 1357 else 1358 shell0 = shell; 1359 1360 /* 1361 * If we have no command, execute the shell. In this case, the shell 1362 * name to be passed in argv[0] is preceded by '-' to indicate that 1363 * this is a login shell. 1364 */ 1365 if (!command) { 1366 char argv0[256]; 1367 1368 /* Start the shell. Set initial character to '-'. */ 1369 argv0[0] = '-'; 1370 1371 if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1) 1372 >= sizeof(argv0) - 1) { 1373 errno = EINVAL; 1374 perror(shell); 1375 exit(1); 1376 } 1377 1378 /* Execute the shell. */ 1379 argv[0] = argv0; 1380 argv[1] = NULL; 1381 execve(shell, argv, env); 1382 1383 /* Executing the shell failed. */ 1384 perror(shell); 1385 exit(1); 1386 } 1387 /* 1388 * Execute the command using the user's shell. This uses the -c 1389 * option to execute the command. 1390 */ 1391 argv[0] = (char *) shell0; 1392 argv[1] = "-c"; 1393 argv[2] = (char *) command; 1394 argv[3] = NULL; 1395 execve(shell, argv, env); 1396 perror(shell); 1397 exit(1); 1398 } 1399 1400 void 1401 session_unused(int id) 1402 { 1403 debug3_f("session id %d unused", id); 1404 if (id >= options.max_sessions || 1405 id >= sessions_nalloc) { 1406 fatal_f("insane session id %d (max %d nalloc %d)", 1407 id, options.max_sessions, sessions_nalloc); 1408 } 1409 memset(&sessions[id], 0, sizeof(*sessions)); 1410 sessions[id].self = id; 1411 sessions[id].used = 0; 1412 sessions[id].chanid = -1; 1413 sessions[id].ptyfd = -1; 1414 sessions[id].ttyfd = -1; 1415 sessions[id].ptymaster = -1; 1416 sessions[id].x11_chanids = NULL; 1417 sessions[id].next_unused = sessions_first_unused; 1418 sessions_first_unused = id; 1419 } 1420 1421 Session * 1422 session_new(void) 1423 { 1424 Session *s, *tmp; 1425 1426 if (sessions_first_unused == -1) { 1427 if (sessions_nalloc >= options.max_sessions) 1428 return NULL; 1429 debug2_f("allocate (allocated %d max %d)", 1430 sessions_nalloc, options.max_sessions); 1431 tmp = xrecallocarray(sessions, sessions_nalloc, 1432 sessions_nalloc + 1, sizeof(*sessions)); 1433 if (tmp == NULL) { 1434 error_f("cannot allocate %d sessions", 1435 sessions_nalloc + 1); 1436 return NULL; 1437 } 1438 sessions = tmp; 1439 session_unused(sessions_nalloc++); 1440 } 1441 1442 if (sessions_first_unused >= sessions_nalloc || 1443 sessions_first_unused < 0) { 1444 fatal_f("insane first_unused %d max %d nalloc %d", 1445 sessions_first_unused, options.max_sessions, 1446 sessions_nalloc); 1447 } 1448 1449 s = &sessions[sessions_first_unused]; 1450 if (s->used) 1451 fatal_f("session %d already used", sessions_first_unused); 1452 sessions_first_unused = s->next_unused; 1453 s->used = 1; 1454 s->next_unused = -1; 1455 debug("session_new: session %d", s->self); 1456 1457 return s; 1458 } 1459 1460 static void 1461 session_dump(void) 1462 { 1463 int i; 1464 for (i = 0; i < sessions_nalloc; i++) { 1465 Session *s = &sessions[i]; 1466 1467 debug("dump: used %d next_unused %d session %d %p " 1468 "channel %d pid %ld", 1469 s->used, 1470 s->next_unused, 1471 s->self, 1472 s, 1473 s->chanid, 1474 (long)s->pid); 1475 } 1476 } 1477 1478 int 1479 session_open(Authctxt *authctxt, int chanid) 1480 { 1481 Session *s = session_new(); 1482 debug("session_open: channel %d", chanid); 1483 if (s == NULL) { 1484 error("no more sessions"); 1485 return 0; 1486 } 1487 s->authctxt = authctxt; 1488 s->pw = authctxt->pw; 1489 if (s->pw == NULL || !authctxt->valid) 1490 fatal("no user for session %d", s->self); 1491 debug("session_open: session %d: link with channel %d", s->self, chanid); 1492 s->chanid = chanid; 1493 return 1; 1494 } 1495 1496 Session * 1497 session_by_tty(char *tty) 1498 { 1499 int i; 1500 for (i = 0; i < sessions_nalloc; i++) { 1501 Session *s = &sessions[i]; 1502 if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) { 1503 debug("session_by_tty: session %d tty %s", i, tty); 1504 return s; 1505 } 1506 } 1507 debug("session_by_tty: unknown tty %.100s", tty); 1508 session_dump(); 1509 return NULL; 1510 } 1511 1512 static Session * 1513 session_by_channel(int id) 1514 { 1515 int i; 1516 for (i = 0; i < sessions_nalloc; i++) { 1517 Session *s = &sessions[i]; 1518 if (s->used && s->chanid == id) { 1519 debug("session_by_channel: session %d channel %d", 1520 i, id); 1521 return s; 1522 } 1523 } 1524 debug("session_by_channel: unknown channel %d", id); 1525 session_dump(); 1526 return NULL; 1527 } 1528 1529 static Session * 1530 session_by_x11_channel(int id) 1531 { 1532 int i, j; 1533 1534 for (i = 0; i < sessions_nalloc; i++) { 1535 Session *s = &sessions[i]; 1536 1537 if (s->x11_chanids == NULL || !s->used) 1538 continue; 1539 for (j = 0; s->x11_chanids[j] != -1; j++) { 1540 if (s->x11_chanids[j] == id) { 1541 debug("session_by_x11_channel: session %d " 1542 "channel %d", s->self, id); 1543 return s; 1544 } 1545 } 1546 } 1547 debug("session_by_x11_channel: unknown channel %d", id); 1548 session_dump(); 1549 return NULL; 1550 } 1551 1552 static Session * 1553 session_by_pid(pid_t pid) 1554 { 1555 int i; 1556 debug("session_by_pid: pid %ld", (long)pid); 1557 for (i = 0; i < sessions_nalloc; i++) { 1558 Session *s = &sessions[i]; 1559 if (s->used && s->pid == pid) 1560 return s; 1561 } 1562 error("session_by_pid: unknown pid %ld", (long)pid); 1563 session_dump(); 1564 return NULL; 1565 } 1566 1567 static int 1568 session_window_change_req(struct ssh *ssh, Session *s) 1569 { 1570 int r; 1571 1572 if ((r = sshpkt_get_u32(ssh, &s->col)) != 0 || 1573 (r = sshpkt_get_u32(ssh, &s->row)) != 0 || 1574 (r = sshpkt_get_u32(ssh, &s->xpixel)) != 0 || 1575 (r = sshpkt_get_u32(ssh, &s->ypixel)) != 0 || 1576 (r = sshpkt_get_end(ssh)) != 0) 1577 sshpkt_fatal(ssh, r, "%s: parse packet", __func__); 1578 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel); 1579 return 1; 1580 } 1581 1582 static int 1583 session_pty_req(struct ssh *ssh, Session *s) 1584 { 1585 int r; 1586 1587 if (!auth_opts->permit_pty_flag || !options.permit_tty) { 1588 debug("Allocating a pty not permitted for this connection."); 1589 return 0; 1590 } 1591 if (s->ttyfd != -1) { 1592 ssh_packet_disconnect(ssh, "Protocol error: you already have a pty."); 1593 return 0; 1594 } 1595 1596 if ((r = sshpkt_get_cstring(ssh, &s->term, NULL)) != 0 || 1597 (r = sshpkt_get_u32(ssh, &s->col)) != 0 || 1598 (r = sshpkt_get_u32(ssh, &s->row)) != 0 || 1599 (r = sshpkt_get_u32(ssh, &s->xpixel)) != 0 || 1600 (r = sshpkt_get_u32(ssh, &s->ypixel)) != 0) 1601 sshpkt_fatal(ssh, r, "%s: parse packet", __func__); 1602 1603 if (strcmp(s->term, "") == 0) { 1604 free(s->term); 1605 s->term = NULL; 1606 } 1607 1608 /* Allocate a pty and open it. */ 1609 debug("Allocating pty."); 1610 if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, 1611 sizeof(s->tty)))) { 1612 free(s->term); 1613 s->term = NULL; 1614 s->ptyfd = -1; 1615 s->ttyfd = -1; 1616 error("session_pty_req: session %d alloc failed", s->self); 1617 return 0; 1618 } 1619 debug("session_pty_req: session %d alloc %s", s->self, s->tty); 1620 1621 ssh_tty_parse_modes(ssh, s->ttyfd); 1622 1623 if ((r = sshpkt_get_end(ssh)) != 0) 1624 sshpkt_fatal(ssh, r, "%s: parse packet", __func__); 1625 1626 if (!use_privsep) 1627 pty_setowner(s->pw, s->tty); 1628 1629 /* Set window size from the packet. */ 1630 pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel); 1631 1632 session_proctitle(s); 1633 return 1; 1634 } 1635 1636 static int 1637 session_subsystem_req(struct ssh *ssh, Session *s) 1638 { 1639 struct stat st; 1640 int r, success = 0; 1641 char *prog, *cmd; 1642 u_int i; 1643 1644 if ((r = sshpkt_get_cstring(ssh, &s->subsys, NULL)) != 0 || 1645 (r = sshpkt_get_end(ssh)) != 0) 1646 sshpkt_fatal(ssh, r, "%s: parse packet", __func__); 1647 debug2("subsystem request for %.100s by user %s", s->subsys, 1648 s->pw->pw_name); 1649 1650 for (i = 0; i < options.num_subsystems; i++) { 1651 if (strcmp(s->subsys, options.subsystem_name[i]) == 0) { 1652 prog = options.subsystem_command[i]; 1653 cmd = options.subsystem_args[i]; 1654 if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) { 1655 s->is_subsystem = SUBSYSTEM_INT_SFTP; 1656 debug("subsystem: %s", prog); 1657 } else { 1658 if (stat(prog, &st) == -1) 1659 debug("subsystem: cannot stat %s: %s", 1660 prog, strerror(errno)); 1661 s->is_subsystem = SUBSYSTEM_EXT; 1662 debug("subsystem: exec() %s", cmd); 1663 } 1664 success = do_exec(ssh, s, cmd) == 0; 1665 break; 1666 } 1667 } 1668 1669 if (!success) 1670 logit("subsystem request for %.100s by user %s failed, " 1671 "subsystem not found", s->subsys, s->pw->pw_name); 1672 1673 return success; 1674 } 1675 1676 static int 1677 session_x11_req(struct ssh *ssh, Session *s) 1678 { 1679 int r, success; 1680 u_char single_connection = 0; 1681 1682 if (s->auth_proto != NULL || s->auth_data != NULL) { 1683 error("session_x11_req: session %d: " 1684 "x11 forwarding already active", s->self); 1685 return 0; 1686 } 1687 if ((r = sshpkt_get_u8(ssh, &single_connection)) != 0 || 1688 (r = sshpkt_get_cstring(ssh, &s->auth_proto, NULL)) != 0 || 1689 (r = sshpkt_get_cstring(ssh, &s->auth_data, NULL)) != 0 || 1690 (r = sshpkt_get_u32(ssh, &s->screen)) != 0 || 1691 (r = sshpkt_get_end(ssh)) != 0) 1692 sshpkt_fatal(ssh, r, "%s: parse packet", __func__); 1693 1694 s->single_connection = single_connection; 1695 1696 if (xauth_valid_string(s->auth_proto) && 1697 xauth_valid_string(s->auth_data)) 1698 success = session_setup_x11fwd(ssh, s); 1699 else { 1700 success = 0; 1701 error("Invalid X11 forwarding data"); 1702 } 1703 if (!success) { 1704 free(s->auth_proto); 1705 free(s->auth_data); 1706 s->auth_proto = NULL; 1707 s->auth_data = NULL; 1708 } 1709 return success; 1710 } 1711 1712 static int 1713 session_shell_req(struct ssh *ssh, Session *s) 1714 { 1715 int r; 1716 1717 if ((r = sshpkt_get_end(ssh)) != 0) 1718 sshpkt_fatal(ssh, r, "%s: parse packet", __func__); 1719 return do_exec(ssh, s, NULL) == 0; 1720 } 1721 1722 static int 1723 session_exec_req(struct ssh *ssh, Session *s) 1724 { 1725 u_int success; 1726 int r; 1727 char *command = NULL; 1728 1729 if ((r = sshpkt_get_cstring(ssh, &command, NULL)) != 0 || 1730 (r = sshpkt_get_end(ssh)) != 0) 1731 sshpkt_fatal(ssh, r, "%s: parse packet", __func__); 1732 1733 success = do_exec(ssh, s, command) == 0; 1734 free(command); 1735 return success; 1736 } 1737 1738 static int 1739 session_break_req(struct ssh *ssh, Session *s) 1740 { 1741 int r; 1742 1743 if ((r = sshpkt_get_u32(ssh, NULL)) != 0 || /* ignore */ 1744 (r = sshpkt_get_end(ssh)) != 0) 1745 sshpkt_fatal(ssh, r, "%s: parse packet", __func__); 1746 1747 if (s->ptymaster == -1 || tcsendbreak(s->ptymaster, 0) == -1) 1748 return 0; 1749 return 1; 1750 } 1751 1752 static int 1753 session_env_req(struct ssh *ssh, Session *s) 1754 { 1755 char *name, *val; 1756 u_int i; 1757 int r; 1758 1759 if ((r = sshpkt_get_cstring(ssh, &name, NULL)) != 0 || 1760 (r = sshpkt_get_cstring(ssh, &val, NULL)) != 0 || 1761 (r = sshpkt_get_end(ssh)) != 0) 1762 sshpkt_fatal(ssh, r, "%s: parse packet", __func__); 1763 1764 /* Don't set too many environment variables */ 1765 if (s->num_env > 128) { 1766 debug2("Ignoring env request %s: too many env vars", name); 1767 goto fail; 1768 } 1769 1770 for (i = 0; i < options.num_accept_env; i++) { 1771 if (match_pattern(name, options.accept_env[i])) { 1772 debug2("Setting env %d: %s=%s", s->num_env, name, val); 1773 s->env = xrecallocarray(s->env, s->num_env, 1774 s->num_env + 1, sizeof(*s->env)); 1775 s->env[s->num_env].name = name; 1776 s->env[s->num_env].val = val; 1777 s->num_env++; 1778 return (1); 1779 } 1780 } 1781 debug2("Ignoring env request %s: disallowed name", name); 1782 1783 fail: 1784 free(name); 1785 free(val); 1786 return (0); 1787 } 1788 1789 /* 1790 * Conversion of signals from ssh channel request names. 1791 * Subset of signals from RFC 4254 section 6.10C, with SIGINFO as 1792 * local extension. 1793 */ 1794 static int 1795 name2sig(char *name) 1796 { 1797 #define SSH_SIG(x) if (strcmp(name, #x) == 0) return SIG ## x 1798 SSH_SIG(HUP); 1799 SSH_SIG(INT); 1800 SSH_SIG(KILL); 1801 SSH_SIG(QUIT); 1802 SSH_SIG(TERM); 1803 SSH_SIG(USR1); 1804 SSH_SIG(USR2); 1805 #undef SSH_SIG 1806 if (strcmp(name, "INFO@openssh.com") == 0) 1807 return SIGINFO; 1808 return -1; 1809 } 1810 1811 static int 1812 session_signal_req(struct ssh *ssh, Session *s) 1813 { 1814 char *signame = NULL; 1815 int r, sig, success = 0; 1816 1817 if ((r = sshpkt_get_cstring(ssh, &signame, NULL)) != 0 || 1818 (r = sshpkt_get_end(ssh)) != 0) { 1819 error_fr(r, "parse"); 1820 goto out; 1821 } 1822 if ((sig = name2sig(signame)) == -1) { 1823 error_f("unsupported signal \"%s\"", signame); 1824 goto out; 1825 } 1826 if (s->pid <= 0) { 1827 error_f("no pid for session %d", s->self); 1828 goto out; 1829 } 1830 if (s->forced || s->is_subsystem) { 1831 error_f("refusing to send signal %s to %s session", 1832 signame, s->forced ? "forced-command" : "subsystem"); 1833 goto out; 1834 } 1835 if (!use_privsep || mm_is_monitor()) { 1836 error_f("session signalling requires privilege separation"); 1837 goto out; 1838 } 1839 1840 debug_f("signal %s, killpg(%ld, %d)", signame, (long)s->pid, sig); 1841 temporarily_use_uid(s->pw); 1842 r = killpg(s->pid, sig); 1843 restore_uid(); 1844 if (r != 0) { 1845 error_f("killpg(%ld, %d): %s", (long)s->pid, 1846 sig, strerror(errno)); 1847 goto out; 1848 } 1849 1850 /* success */ 1851 success = 1; 1852 out: 1853 free(signame); 1854 return success; 1855 } 1856 1857 static int 1858 session_auth_agent_req(struct ssh *ssh, Session *s) 1859 { 1860 static int called = 0; 1861 int r; 1862 1863 if ((r = sshpkt_get_end(ssh)) != 0) 1864 sshpkt_fatal(ssh, r, "%s: parse packet", __func__); 1865 if (!auth_opts->permit_agent_forwarding_flag || 1866 !options.allow_agent_forwarding) { 1867 debug_f("agent forwarding disabled"); 1868 return 0; 1869 } 1870 if (called) { 1871 return 0; 1872 } else { 1873 called = 1; 1874 return auth_input_request_forwarding(ssh, s->pw); 1875 } 1876 } 1877 1878 int 1879 session_input_channel_req(struct ssh *ssh, Channel *c, const char *rtype) 1880 { 1881 int success = 0; 1882 Session *s; 1883 1884 if ((s = session_by_channel(c->self)) == NULL) { 1885 logit_f("no session %d req %.100s", c->self, rtype); 1886 return 0; 1887 } 1888 debug_f("session %d req %s", s->self, rtype); 1889 1890 /* 1891 * a session is in LARVAL state until a shell, a command 1892 * or a subsystem is executed 1893 */ 1894 if (c->type == SSH_CHANNEL_LARVAL) { 1895 if (strcmp(rtype, "shell") == 0) { 1896 success = session_shell_req(ssh, s); 1897 } else if (strcmp(rtype, "exec") == 0) { 1898 success = session_exec_req(ssh, s); 1899 } else if (strcmp(rtype, "pty-req") == 0) { 1900 success = session_pty_req(ssh, s); 1901 } else if (strcmp(rtype, "x11-req") == 0) { 1902 success = session_x11_req(ssh, s); 1903 } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) { 1904 success = session_auth_agent_req(ssh, s); 1905 } else if (strcmp(rtype, "subsystem") == 0) { 1906 success = session_subsystem_req(ssh, s); 1907 } else if (strcmp(rtype, "env") == 0) { 1908 success = session_env_req(ssh, s); 1909 } 1910 } 1911 if (strcmp(rtype, "window-change") == 0) { 1912 success = session_window_change_req(ssh, s); 1913 } else if (strcmp(rtype, "break") == 0) { 1914 success = session_break_req(ssh, s); 1915 } else if (strcmp(rtype, "signal") == 0) { 1916 success = session_signal_req(ssh, s); 1917 } 1918 1919 return success; 1920 } 1921 1922 void 1923 session_set_fds(struct ssh *ssh, Session *s, 1924 int fdin, int fdout, int fderr, int ignore_fderr, int is_tty) 1925 { 1926 /* 1927 * now that have a child and a pipe to the child, 1928 * we can activate our channel and register the fd's 1929 */ 1930 if (s->chanid == -1) 1931 fatal("no channel for session %d", s->self); 1932 channel_set_fds(ssh, s->chanid, 1933 fdout, fdin, fderr, 1934 ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ, 1935 1, is_tty, CHAN_SES_WINDOW_DEFAULT); 1936 } 1937 1938 /* 1939 * Function to perform pty cleanup. Also called if we get aborted abnormally 1940 * (e.g., due to a dropped connection). 1941 */ 1942 void 1943 session_pty_cleanup2(Session *s) 1944 { 1945 if (s == NULL) { 1946 error_f("no session"); 1947 return; 1948 } 1949 if (s->ttyfd == -1) 1950 return; 1951 1952 debug_f("session %d release %s", s->self, s->tty); 1953 1954 /* Record that the user has logged out. */ 1955 if (s->pid != 0) 1956 record_logout(s->pid, s->tty); 1957 1958 /* Release the pseudo-tty. */ 1959 if (getuid() == 0) 1960 pty_release(s->tty); 1961 1962 /* 1963 * Close the server side of the socket pairs. We must do this after 1964 * the pty cleanup, so that another process doesn't get this pty 1965 * while we're still cleaning up. 1966 */ 1967 if (s->ptymaster != -1 && close(s->ptymaster) == -1) 1968 error("close(s->ptymaster/%d): %s", 1969 s->ptymaster, strerror(errno)); 1970 1971 /* unlink pty from session */ 1972 s->ttyfd = -1; 1973 } 1974 1975 void 1976 session_pty_cleanup(Session *s) 1977 { 1978 PRIVSEP(session_pty_cleanup2(s)); 1979 } 1980 1981 static char * 1982 sig2name(int sig) 1983 { 1984 #define SSH_SIG(x) if (sig == SIG ## x) return #x 1985 SSH_SIG(ABRT); 1986 SSH_SIG(ALRM); 1987 SSH_SIG(FPE); 1988 SSH_SIG(HUP); 1989 SSH_SIG(ILL); 1990 SSH_SIG(INT); 1991 SSH_SIG(KILL); 1992 SSH_SIG(PIPE); 1993 SSH_SIG(QUIT); 1994 SSH_SIG(SEGV); 1995 SSH_SIG(TERM); 1996 SSH_SIG(USR1); 1997 SSH_SIG(USR2); 1998 #undef SSH_SIG 1999 return "SIG@openssh.com"; 2000 } 2001 2002 static void 2003 session_close_x11(struct ssh *ssh, int id) 2004 { 2005 Channel *c; 2006 2007 if ((c = channel_by_id(ssh, id)) == NULL) { 2008 debug_f("x11 channel %d missing", id); 2009 } else { 2010 /* Detach X11 listener */ 2011 debug_f("detach x11 channel %d", id); 2012 channel_cancel_cleanup(ssh, id); 2013 if (c->ostate != CHAN_OUTPUT_CLOSED) 2014 chan_mark_dead(ssh, c); 2015 } 2016 } 2017 2018 static void 2019 session_close_single_x11(struct ssh *ssh, int id, void *arg) 2020 { 2021 Session *s; 2022 u_int i; 2023 2024 debug3_f("channel %d", id); 2025 channel_cancel_cleanup(ssh, id); 2026 if ((s = session_by_x11_channel(id)) == NULL) 2027 fatal_f("no x11 channel %d", id); 2028 for (i = 0; s->x11_chanids[i] != -1; i++) { 2029 debug_f("session %d: closing channel %d", 2030 s->self, s->x11_chanids[i]); 2031 /* 2032 * The channel "id" is already closing, but make sure we 2033 * close all of its siblings. 2034 */ 2035 if (s->x11_chanids[i] != id) 2036 session_close_x11(ssh, s->x11_chanids[i]); 2037 } 2038 free(s->x11_chanids); 2039 s->x11_chanids = NULL; 2040 free(s->display); 2041 s->display = NULL; 2042 free(s->auth_proto); 2043 s->auth_proto = NULL; 2044 free(s->auth_data); 2045 s->auth_data = NULL; 2046 free(s->auth_display); 2047 s->auth_display = NULL; 2048 } 2049 2050 static void 2051 session_exit_message(struct ssh *ssh, Session *s, int status) 2052 { 2053 Channel *c; 2054 int r; 2055 2056 if ((c = channel_lookup(ssh, s->chanid)) == NULL) 2057 fatal_f("session %d: no channel %d", s->self, s->chanid); 2058 debug_f("session %d channel %d pid %ld", 2059 s->self, s->chanid, (long)s->pid); 2060 2061 if (WIFEXITED(status)) { 2062 channel_request_start(ssh, s->chanid, "exit-status", 0); 2063 if ((r = sshpkt_put_u32(ssh, WEXITSTATUS(status))) != 0 || 2064 (r = sshpkt_send(ssh)) != 0) 2065 sshpkt_fatal(ssh, r, "%s: exit reply", __func__); 2066 } else if (WIFSIGNALED(status)) { 2067 channel_request_start(ssh, s->chanid, "exit-signal", 0); 2068 if ((r = sshpkt_put_cstring(ssh, sig2name(WTERMSIG(status)))) != 0 || 2069 (r = sshpkt_put_u8(ssh, WCOREDUMP(status)? 1 : 0)) != 0 || 2070 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2071 (r = sshpkt_put_cstring(ssh, "")) != 0 || 2072 (r = sshpkt_send(ssh)) != 0) 2073 sshpkt_fatal(ssh, r, "%s: exit reply", __func__); 2074 } else { 2075 /* Some weird exit cause. Just exit. */ 2076 ssh_packet_disconnect(ssh, "wait returned status %04x.", status); 2077 } 2078 2079 /* disconnect channel */ 2080 debug_f("release channel %d", s->chanid); 2081 2082 /* 2083 * Adjust cleanup callback attachment to send close messages when 2084 * the channel gets EOF. The session will be then be closed 2085 * by session_close_by_channel when the child sessions close their fds. 2086 */ 2087 channel_register_cleanup(ssh, c->self, session_close_by_channel, 1); 2088 2089 /* 2090 * emulate a write failure with 'chan_write_failed', nobody will be 2091 * interested in data we write. 2092 * Note that we must not call 'chan_read_failed', since there could 2093 * be some more data waiting in the pipe. 2094 */ 2095 if (c->ostate != CHAN_OUTPUT_CLOSED) 2096 chan_write_failed(ssh, c); 2097 } 2098 2099 void 2100 session_close(struct ssh *ssh, Session *s) 2101 { 2102 u_int i; 2103 2104 verbose("Close session: user %s from %.200s port %d id %d", 2105 s->pw->pw_name, 2106 ssh_remote_ipaddr(ssh), 2107 ssh_remote_port(ssh), 2108 s->self); 2109 2110 if (s->ttyfd != -1) 2111 session_pty_cleanup(s); 2112 free(s->term); 2113 free(s->display); 2114 free(s->x11_chanids); 2115 free(s->auth_display); 2116 free(s->auth_data); 2117 free(s->auth_proto); 2118 free(s->subsys); 2119 if (s->env != NULL) { 2120 for (i = 0; i < s->num_env; i++) { 2121 free(s->env[i].name); 2122 free(s->env[i].val); 2123 } 2124 free(s->env); 2125 } 2126 session_proctitle(s); 2127 session_unused(s->self); 2128 } 2129 2130 void 2131 session_close_by_pid(struct ssh *ssh, pid_t pid, int status) 2132 { 2133 Session *s = session_by_pid(pid); 2134 if (s == NULL) { 2135 debug_f("no session for pid %ld", (long)pid); 2136 return; 2137 } 2138 if (s->chanid != -1) 2139 session_exit_message(ssh, s, status); 2140 if (s->ttyfd != -1) 2141 session_pty_cleanup(s); 2142 s->pid = 0; 2143 } 2144 2145 /* 2146 * this is called when a channel dies before 2147 * the session 'child' itself dies 2148 */ 2149 void 2150 session_close_by_channel(struct ssh *ssh, int id, void *arg) 2151 { 2152 Session *s = session_by_channel(id); 2153 u_int i; 2154 2155 if (s == NULL) { 2156 debug_f("no session for id %d", id); 2157 return; 2158 } 2159 debug_f("channel %d child %ld", id, (long)s->pid); 2160 if (s->pid != 0) { 2161 debug_f("channel %d: has child, ttyfd %d", id, s->ttyfd); 2162 /* 2163 * delay detach of session, but release pty, since 2164 * the fd's to the child are already closed 2165 */ 2166 if (s->ttyfd != -1) 2167 session_pty_cleanup(s); 2168 return; 2169 } 2170 /* detach by removing callback */ 2171 channel_cancel_cleanup(ssh, s->chanid); 2172 2173 /* Close any X11 listeners associated with this session */ 2174 if (s->x11_chanids != NULL) { 2175 for (i = 0; s->x11_chanids[i] != -1; i++) { 2176 session_close_x11(ssh, s->x11_chanids[i]); 2177 s->x11_chanids[i] = -1; 2178 } 2179 } 2180 2181 s->chanid = -1; 2182 session_close(ssh, s); 2183 } 2184 2185 void 2186 session_destroy_all(struct ssh *ssh, void (*closefunc)(Session *)) 2187 { 2188 int i; 2189 for (i = 0; i < sessions_nalloc; i++) { 2190 Session *s = &sessions[i]; 2191 if (s->used) { 2192 if (closefunc != NULL) 2193 closefunc(s); 2194 else 2195 session_close(ssh, s); 2196 } 2197 } 2198 } 2199 2200 static char * 2201 session_tty_list(void) 2202 { 2203 static char buf[1024]; 2204 int i; 2205 buf[0] = '\0'; 2206 for (i = 0; i < sessions_nalloc; i++) { 2207 Session *s = &sessions[i]; 2208 if (s->used && s->ttyfd != -1) { 2209 if (buf[0] != '\0') 2210 strlcat(buf, ",", sizeof buf); 2211 strlcat(buf, strrchr(s->tty, '/') + 1, sizeof buf); 2212 } 2213 } 2214 if (buf[0] == '\0') 2215 strlcpy(buf, "notty", sizeof buf); 2216 return buf; 2217 } 2218 2219 void 2220 session_proctitle(Session *s) 2221 { 2222 if (s->pw == NULL) 2223 error("no user for session %d", s->self); 2224 else 2225 setproctitle("%s@%s", s->pw->pw_name, session_tty_list()); 2226 } 2227 2228 int 2229 session_setup_x11fwd(struct ssh *ssh, Session *s) 2230 { 2231 struct stat st; 2232 char display[512], auth_display[512]; 2233 char hostname[NI_MAXHOST]; 2234 u_int i; 2235 2236 if (!auth_opts->permit_x11_forwarding_flag) { 2237 ssh_packet_send_debug(ssh, "X11 forwarding disabled by key options."); 2238 return 0; 2239 } 2240 if (!options.x11_forwarding) { 2241 debug("X11 forwarding disabled in server configuration file."); 2242 return 0; 2243 } 2244 if (options.xauth_location == NULL || 2245 (stat(options.xauth_location, &st) == -1)) { 2246 ssh_packet_send_debug(ssh, "No xauth program; cannot forward X11."); 2247 return 0; 2248 } 2249 if (s->display != NULL) { 2250 debug("X11 display already set."); 2251 return 0; 2252 } 2253 if (x11_create_display_inet(ssh, options.x11_display_offset, 2254 options.x11_use_localhost, s->single_connection, 2255 &s->display_number, &s->x11_chanids) == -1) { 2256 debug("x11_create_display_inet failed."); 2257 return 0; 2258 } 2259 for (i = 0; s->x11_chanids[i] != -1; i++) { 2260 channel_register_cleanup(ssh, s->x11_chanids[i], 2261 session_close_single_x11, 0); 2262 } 2263 2264 /* Set up a suitable value for the DISPLAY variable. */ 2265 if (gethostname(hostname, sizeof(hostname)) == -1) 2266 fatal("gethostname: %.100s", strerror(errno)); 2267 /* 2268 * auth_display must be used as the displayname when the 2269 * authorization entry is added with xauth(1). This will be 2270 * different than the DISPLAY string for localhost displays. 2271 */ 2272 if (options.x11_use_localhost) { 2273 snprintf(display, sizeof display, "localhost:%u.%u", 2274 s->display_number, s->screen); 2275 snprintf(auth_display, sizeof auth_display, "unix:%u.%u", 2276 s->display_number, s->screen); 2277 s->display = xstrdup(display); 2278 s->auth_display = xstrdup(auth_display); 2279 } else { 2280 snprintf(display, sizeof display, "%.400s:%u.%u", hostname, 2281 s->display_number, s->screen); 2282 s->display = xstrdup(display); 2283 s->auth_display = xstrdup(display); 2284 } 2285 2286 return 1; 2287 } 2288 2289 static void 2290 do_authenticated2(struct ssh *ssh, Authctxt *authctxt) 2291 { 2292 server_loop2(ssh, authctxt); 2293 } 2294 2295 void 2296 do_cleanup(struct ssh *ssh, Authctxt *authctxt) 2297 { 2298 static int called = 0; 2299 2300 debug("do_cleanup"); 2301 2302 /* no cleanup if we're in the child for login shell */ 2303 if (is_child) 2304 return; 2305 2306 /* avoid double cleanup */ 2307 if (called) 2308 return; 2309 called = 1; 2310 2311 if (authctxt == NULL || !authctxt->authenticated) 2312 return; 2313 #ifdef KRB5 2314 if (options.kerberos_ticket_cleanup && 2315 authctxt->krb5_ctx) 2316 krb5_cleanup_proc(authctxt); 2317 #endif 2318 2319 #ifdef GSSAPI 2320 if (options.gss_cleanup_creds) 2321 ssh_gssapi_cleanup_creds(); 2322 #endif 2323 2324 /* remove agent socket */ 2325 auth_sock_cleanup_proc(authctxt->pw); 2326 2327 /* remove userauth info */ 2328 if (auth_info_file != NULL) { 2329 temporarily_use_uid(authctxt->pw); 2330 unlink(auth_info_file); 2331 restore_uid(); 2332 free(auth_info_file); 2333 auth_info_file = NULL; 2334 } 2335 2336 /* 2337 * Cleanup ptys/utmp only if privsep is disabled, 2338 * or if running in monitor. 2339 */ 2340 if (!use_privsep || mm_is_monitor()) 2341 session_destroy_all(ssh, session_pty_cleanup2); 2342 } 2343 2344 /* Return a name for the remote host that fits inside utmp_size */ 2345 2346 const char * 2347 session_get_remote_name_or_ip(struct ssh *ssh, u_int utmp_size, int use_dns) 2348 { 2349 const char *remote = ""; 2350 2351 if (utmp_size > 0) 2352 remote = auth_get_canonical_hostname(ssh, use_dns); 2353 if (utmp_size == 0 || strlen(remote) > utmp_size) 2354 remote = ssh_remote_ipaddr(ssh); 2355 return remote; 2356 } 2357 2358