| 1 | /* $OpenBSD: session.c,v 1.292 2017/09/12 06:32:07 djm Exp $ */ |
| 2 | /* |
| 3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
| 4 | * All rights reserved |
| 5 | * |
| 6 | * As far as I am concerned, the code I have written for this software |
| 7 | * can be used freely for any purpose. Any derived versions of this |
| 8 | * software must be clearly marked as such, and if the derived work is |
| 9 | * incompatible with the protocol description in the RFC file, it must be |
| 10 | * called by a name other than "ssh" or "Secure Shell". |
| 11 | * |
| 12 | * SSH2 support by Markus Friedl. |
| 13 | * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. |
| 14 | * |
| 15 | * Redistribution and use in source and binary forms, with or without |
| 16 | * modification, are permitted provided that the following conditions |
| 17 | * are met: |
| 18 | * 1. Redistributions of source code must retain the above copyright |
| 19 | * notice, this list of conditions and the following disclaimer. |
| 20 | * 2. Redistributions in binary form must reproduce the above copyright |
| 21 | * notice, this list of conditions and the following disclaimer in the |
| 22 | * documentation and/or other materials provided with the distribution. |
| 23 | * |
| 24 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 25 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 26 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 27 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 28 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 29 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 30 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 31 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 32 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 33 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 34 | */ |
| 35 | |
| 36 | #include "includes.h" |
| 37 | |
| 38 | #include <sys/types.h> |
| 39 | #include <sys/param.h> |
| 40 | #ifdef HAVE_SYS_STAT_H |
| 41 | # include <sys/stat.h> |
| 42 | #endif |
| 43 | #include <sys/socket.h> |
| 44 | #include <sys/un.h> |
| 45 | #include <sys/wait.h> |
| 46 | |
| 47 | #include <arpa/inet.h> |
| 48 | |
| 49 | #include <ctype.h> |
| 50 | #include <errno.h> |
| 51 | #include <fcntl.h> |
| 52 | #include <grp.h> |
| 53 | #include <netdb.h> |
| 54 | #ifdef HAVE_PATHS_H |
| 55 | #include <paths.h> |
| 56 | #endif |
| 57 | #include <pwd.h> |
| 58 | #include <signal.h> |
| 59 | #include <stdarg.h> |
| 60 | #include <stdio.h> |
| 61 | #include <stdlib.h> |
| 62 | #include <string.h> |
| 63 | #include <unistd.h> |
| 64 | #include <limits.h> |
| 65 | |
| 66 | #include "openbsd-compat/sys-queue.h" |
| 67 | #include "xmalloc.h" |
| 68 | #include "ssh.h" |
| 69 | #include "ssh2.h" |
| 70 | #include "sshpty.h" |
| 71 | #include "packet.h" |
| 72 | #include "buffer.h" |
| 73 | #include "match.h" |
| 74 | #include "uidswap.h" |
| 75 | #include "compat.h" |
| 76 | #include "channels.h" |
| 77 | #include "key.h" |
| 78 | #include "cipher.h" |
| 79 | #ifdef GSSAPI |
| 80 | #include "ssh-gss.h" |
| 81 | #endif |
| 82 | #include "hostfile.h" |
| 83 | #include "auth.h" |
| 84 | #include "auth-options.h" |
| 85 | #include "authfd.h" |
| 86 | #include "pathnames.h" |
| 87 | #include "log.h" |
| 88 | #include "misc.h" |
| 89 | #include "servconf.h" |
| 90 | #include "sshlogin.h" |
| 91 | #include "serverloop.h" |
| 92 | #include "canohost.h" |
| 93 | #include "session.h" |
| 94 | #include "kex.h" |
| 95 | #include "monitor_wrap.h" |
| 96 | #include "sftp.h" |
| 97 | #include "atomicio.h" |
| 98 | |
| 99 | #if defined(KRB5) && defined(USE_AFS) |
| 100 | #include <kafs.h> |
| 101 | #endif |
| 102 | |
| 103 | #ifdef WITH_SELINUX |
| 104 | #include <selinux/selinux.h> |
| 105 | #endif |
| 106 | |
| 107 | #define IS_INTERNAL_SFTP(c) \ |
| 108 | (!strncmp(c, INTERNAL_SFTP_NAME, sizeof(INTERNAL_SFTP_NAME) - 1) && \ |
| 109 | (c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\0' || \ |
| 110 | c[sizeof(INTERNAL_SFTP_NAME) - 1] == ' ' || \ |
| 111 | c[sizeof(INTERNAL_SFTP_NAME) - 1] == '\t')) |
| 112 | |
| 113 | /* func */ |
| 114 | |
| 115 | Session *session_new(void); |
| 116 | void session_set_fds(struct ssh *, Session *, int, int, int, int, int); |
| 117 | void session_pty_cleanup(Session *); |
| 118 | void session_proctitle(Session *); |
| 119 | int session_setup_x11fwd(struct ssh *, Session *); |
| 120 | int do_exec_pty(struct ssh *, Session *, const char *); |
| 121 | int do_exec_no_pty(struct ssh *, Session *, const char *); |
| 122 | int do_exec(struct ssh *, Session *, const char *); |
| 123 | void do_login(struct ssh *, Session *, const char *); |
| 124 | void do_child(struct ssh *, Session *, const char *); |
| 125 | #ifdef LOGIN_NEEDS_UTMPX |
| 126 | static void do_pre_login(Session *s); |
| 127 | #endif |
| 128 | void do_motd(void); |
| 129 | int check_quietlogin(Session *, const char *); |
| 130 | |
| 131 | static void do_authenticated2(struct ssh *, Authctxt *); |
| 132 | |
| 133 | static int session_pty_req(struct ssh *, Session *); |
| 134 | |
| 135 | /* import */ |
| 136 | extern ServerOptions options; |
| 137 | extern char *__progname; |
| 138 | extern int debug_flag; |
| 139 | extern u_int utmp_len; |
| 140 | extern int startup_pipe; |
| 141 | extern void destroy_sensitive_data(void); |
| 142 | extern Buffer loginmsg; |
| 143 | |
| 144 | /* original command from peer. */ |
| 145 | const char *original_command = NULL; |
| 146 | |
| 147 | /* data */ |
| 148 | static int sessions_first_unused = -1; |
| 149 | static int sessions_nalloc = 0; |
| 150 | static Session *sessions = NULL; |
| 151 | |
| 152 | #define SUBSYSTEM_NONE 0 |
| 153 | #define SUBSYSTEM_EXT 1 |
| 154 | #define SUBSYSTEM_INT_SFTP 2 |
| 155 | #define SUBSYSTEM_INT_SFTP_ERROR 3 |
| 156 | |
| 157 | #ifdef HAVE_LOGIN_CAP |
| 158 | login_cap_t *lc; |
| 159 | #endif |
| 160 | |
| 161 | static int is_child = 0; |
| 162 | static int in_chroot = 0; |
| 163 | |
| 164 | /* File containing userauth info, if ExposeAuthInfo set */ |
| 165 | static char *auth_info_file = NULL; |
| 166 | |
| 167 | /* Name and directory of socket for authentication agent forwarding. */ |
| 168 | static char *auth_sock_name = NULL; |
| 169 | static char *auth_sock_dir = NULL; |
| 170 | |
| 171 | /* removes the agent forwarding socket */ |
| 172 | |
| 173 | static void |
| 174 | auth_sock_cleanup_proc(struct passwd *pw) |
| 175 | { |
| 176 | if (auth_sock_name != NULL) { |
| 177 | temporarily_use_uid(pw); |
| 178 | unlink(auth_sock_name); |
| 179 | rmdir(auth_sock_dir); |
| 180 | auth_sock_name = NULL; |
| 181 | restore_uid(); |
| 182 | } |
| 183 | } |
| 184 | |
| 185 | static int |
| 186 | auth_input_request_forwarding(struct ssh *ssh, struct passwd * pw) |
| 187 | { |
| 188 | Channel *nc; |
| 189 | int sock = -1; |
| 190 | |
| 191 | if (auth_sock_name != NULL) { |
| 192 | error("authentication forwarding requested twice."); |
| 193 | return 0; |
| 194 | } |
| 195 | |
| 196 | /* Temporarily drop privileged uid for mkdir/bind. */ |
| 197 | temporarily_use_uid(pw); |
| 198 | |
| 199 | /* Allocate a buffer for the socket name, and format the name. */ |
| 200 | auth_sock_dir = xstrdup("/tmp/ssh-XXXXXXXXXX"); |
| 201 | |
| 202 | /* Create private directory for socket */ |
| 203 | if (mkdtemp(auth_sock_dir) == NULL) { |
| 204 | packet_send_debug("Agent forwarding disabled: " |
| 205 | "mkdtemp() failed: %.100s", strerror(errno)); |
| 206 | restore_uid(); |
| 207 | free(auth_sock_dir); |
| 208 | auth_sock_dir = NULL; |
| 209 | goto authsock_err; |
| 210 | } |
| 211 | |
| 212 | xasprintf(&auth_sock_name, "%s/agent.%ld", |
| 213 | auth_sock_dir, (long) getpid()); |
| 214 | |
| 215 | /* Start a Unix listener on auth_sock_name. */ |
| 216 | sock = unix_listener(auth_sock_name, SSH_LISTEN_BACKLOG, 0); |
| 217 | |
| 218 | /* Restore the privileged uid. */ |
| 219 | restore_uid(); |
| 220 | |
| 221 | /* Check for socket/bind/listen failure. */ |
| 222 | if (sock < 0) |
| 223 | goto authsock_err; |
| 224 | |
| 225 | /* Allocate a channel for the authentication agent socket. */ |
| 226 | nc = channel_new(ssh, "auth socket", |
| 227 | SSH_CHANNEL_AUTH_SOCKET, sock, sock, -1, |
| 228 | CHAN_X11_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, |
| 229 | 0, "auth socket", 1); |
| 230 | nc->path = xstrdup(auth_sock_name); |
| 231 | return 1; |
| 232 | |
| 233 | authsock_err: |
| 234 | free(auth_sock_name); |
| 235 | if (auth_sock_dir != NULL) { |
| 236 | rmdir(auth_sock_dir); |
| 237 | free(auth_sock_dir); |
| 238 | } |
| 239 | if (sock != -1) |
| 240 | close(sock); |
| 241 | auth_sock_name = NULL; |
| 242 | auth_sock_dir = NULL; |
| 243 | return 0; |
| 244 | } |
| 245 | |
| 246 | static void |
| 247 | display_loginmsg(void) |
| 248 | { |
| 249 | if (buffer_len(&loginmsg) > 0) { |
| 250 | buffer_append(&loginmsg, "\0", 1); |
| 251 | printf("%s", (char *)buffer_ptr(&loginmsg)); |
| 252 | buffer_clear(&loginmsg); |
| 253 | } |
| 254 | } |
| 255 | |
| 256 | static void |
| 257 | prepare_auth_info_file(struct passwd *pw, struct sshbuf *info) |
| 258 | { |
| 259 | int fd = -1, success = 0; |
| 260 | |
| 261 | if (!options.expose_userauth_info || info == NULL) |
| 262 | return; |
| 263 | |
| 264 | temporarily_use_uid(pw); |
| 265 | auth_info_file = xstrdup("/tmp/sshauth.XXXXXXXXXXXXXXX"); |
| 266 | if ((fd = mkstemp(auth_info_file)) == -1) { |
| 267 | error("%s: mkstemp: %s", __func__, strerror(errno)); |
| 268 | goto out; |
| 269 | } |
| 270 | if (atomicio(vwrite, fd, sshbuf_mutable_ptr(info), |
| 271 | sshbuf_len(info)) != sshbuf_len(info)) { |
| 272 | error("%s: write: %s", __func__, strerror(errno)); |
| 273 | goto out; |
| 274 | } |
| 275 | if (close(fd) != 0) { |
| 276 | error("%s: close: %s", __func__, strerror(errno)); |
| 277 | goto out; |
| 278 | } |
| 279 | success = 1; |
| 280 | out: |
| 281 | if (!success) { |
| 282 | if (fd != -1) |
| 283 | close(fd); |
| 284 | free(auth_info_file); |
| 285 | auth_info_file = NULL; |
| 286 | } |
| 287 | restore_uid(); |
| 288 | } |
| 289 | |
| 290 | void |
| 291 | do_authenticated(struct ssh *ssh, Authctxt *authctxt) |
| 292 | { |
| 293 | setproctitle("%s", authctxt->pw->pw_name); |
| 294 | |
| 295 | /* setup the channel layer */ |
| 296 | /* XXX - streamlocal? */ |
| 297 | if (no_port_forwarding_flag || options.disable_forwarding || |
| 298 | (options.allow_tcp_forwarding & FORWARD_LOCAL) == 0) |
| 299 | channel_disable_adm_local_opens(ssh); |
| 300 | else |
| 301 | channel_permit_all_opens(ssh); |
| 302 | |
| 303 | auth_debug_send(); |
| 304 | |
| 305 | prepare_auth_info_file(authctxt->pw, authctxt->session_info); |
| 306 | |
| 307 | do_authenticated2(ssh, authctxt); |
| 308 | |
| 309 | do_cleanup(ssh, authctxt); |
| 310 | } |
| 311 | |
| 312 | /* Check untrusted xauth strings for metacharacters */ |
| 313 | static int |
| 314 | xauth_valid_string(const char *s) |
| 315 | { |
| 316 | size_t i; |
| 317 | |
| 318 | for (i = 0; s[i] != '\0'; i++) { |
| 319 | if (!isalnum((u_char)s[i]) && |
| 320 | s[i] != '.' && s[i] != ':' && s[i] != '/' && |
| 321 | s[i] != '-' && s[i] != '_') |
| 322 | return 0; |
| 323 | } |
| 324 | return 1; |
| 325 | } |
| 326 | |
| 327 | #define USE_PIPES 1 |
| 328 | /* |
| 329 | * This is called to fork and execute a command when we have no tty. This |
| 330 | * will call do_child from the child, and server_loop from the parent after |
| 331 | * setting up file descriptors and such. |
| 332 | */ |
| 333 | int |
| 334 | do_exec_no_pty(struct ssh *ssh, Session *s, const char *command) |
| 335 | { |
| 336 | pid_t pid; |
| 337 | |
| 338 | #ifdef USE_PIPES |
| 339 | int pin[2], pout[2], perr[2]; |
| 340 | |
| 341 | if (s == NULL) |
| 342 | fatal("do_exec_no_pty: no session"); |
| 343 | |
| 344 | /* Allocate pipes for communicating with the program. */ |
| 345 | if (pipe(pin) < 0) { |
| 346 | error("%s: pipe in: %.100s", __func__, strerror(errno)); |
| 347 | return -1; |
| 348 | } |
| 349 | if (pipe(pout) < 0) { |
| 350 | error("%s: pipe out: %.100s", __func__, strerror(errno)); |
| 351 | close(pin[0]); |
| 352 | close(pin[1]); |
| 353 | return -1; |
| 354 | } |
| 355 | if (pipe(perr) < 0) { |
| 356 | error("%s: pipe err: %.100s", __func__, |
| 357 | strerror(errno)); |
| 358 | close(pin[0]); |
| 359 | close(pin[1]); |
| 360 | close(pout[0]); |
| 361 | close(pout[1]); |
| 362 | return -1; |
| 363 | } |
| 364 | #else |
| 365 | int inout[2], err[2]; |
| 366 | |
| 367 | if (s == NULL) |
| 368 | fatal("do_exec_no_pty: no session"); |
| 369 | |
| 370 | /* Uses socket pairs to communicate with the program. */ |
| 371 | if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0) { |
| 372 | error("%s: socketpair #1: %.100s", __func__, strerror(errno)); |
| 373 | return -1; |
| 374 | } |
| 375 | if (socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) { |
| 376 | error("%s: socketpair #2: %.100s", __func__, |
| 377 | strerror(errno)); |
| 378 | close(inout[0]); |
| 379 | close(inout[1]); |
| 380 | return -1; |
| 381 | } |
| 382 | #endif |
| 383 | |
| 384 | session_proctitle(s); |
| 385 | |
| 386 | /* Fork the child. */ |
| 387 | switch ((pid = fork())) { |
| 388 | case -1: |
| 389 | error("%s: fork: %.100s", __func__, strerror(errno)); |
| 390 | #ifdef USE_PIPES |
| 391 | close(pin[0]); |
| 392 | close(pin[1]); |
| 393 | close(pout[0]); |
| 394 | close(pout[1]); |
| 395 | close(perr[0]); |
| 396 | close(perr[1]); |
| 397 | #else |
| 398 | close(inout[0]); |
| 399 | close(inout[1]); |
| 400 | close(err[0]); |
| 401 | close(err[1]); |
| 402 | #endif |
| 403 | return -1; |
| 404 | case 0: |
| 405 | is_child = 1; |
| 406 | |
| 407 | /* |
| 408 | * Create a new session and process group since the 4.4BSD |
| 409 | * setlogin() affects the entire process group. |
| 410 | */ |
| 411 | if (setsid() < 0) |
| 412 | error("setsid failed: %.100s", strerror(errno)); |
| 413 | |
| 414 | #ifdef USE_PIPES |
| 415 | /* |
| 416 | * Redirect stdin. We close the parent side of the socket |
| 417 | * pair, and make the child side the standard input. |
| 418 | */ |
| 419 | close(pin[1]); |
| 420 | if (dup2(pin[0], 0) < 0) |
| 421 | perror("dup2 stdin"); |
| 422 | close(pin[0]); |
| 423 | |
| 424 | /* Redirect stdout. */ |
| 425 | close(pout[0]); |
| 426 | if (dup2(pout[1], 1) < 0) |
| 427 | perror("dup2 stdout"); |
| 428 | close(pout[1]); |
| 429 | |
| 430 | /* Redirect stderr. */ |
| 431 | close(perr[0]); |
| 432 | if (dup2(perr[1], 2) < 0) |
| 433 | perror("dup2 stderr"); |
| 434 | close(perr[1]); |
| 435 | #else |
| 436 | /* |
| 437 | * Redirect stdin, stdout, and stderr. Stdin and stdout will |
| 438 | * use the same socket, as some programs (particularly rdist) |
| 439 | * seem to depend on it. |
| 440 | */ |
| 441 | close(inout[1]); |
| 442 | close(err[1]); |
| 443 | if (dup2(inout[0], 0) < 0) /* stdin */ |
| 444 | perror("dup2 stdin"); |
| 445 | if (dup2(inout[0], 1) < 0) /* stdout (same as stdin) */ |
| 446 | perror("dup2 stdout"); |
| 447 | close(inout[0]); |
| 448 | if (dup2(err[0], 2) < 0) /* stderr */ |
| 449 | perror("dup2 stderr"); |
| 450 | close(err[0]); |
| 451 | #endif |
| 452 | |
| 453 | |
| 454 | #ifdef _UNICOS |
| 455 | cray_init_job(s->pw); /* set up cray jid and tmpdir */ |
| 456 | #endif |
| 457 | |
| 458 | /* Do processing for the child (exec command etc). */ |
| 459 | do_child(ssh, s, command); |
| 460 | /* NOTREACHED */ |
| 461 | default: |
| 462 | break; |
| 463 | } |
| 464 | |
| 465 | #ifdef _UNICOS |
| 466 | signal(WJSIGNAL, cray_job_termination_handler); |
| 467 | #endif /* _UNICOS */ |
| 468 | #ifdef HAVE_CYGWIN |
| 469 | cygwin_set_impersonation_token(INVALID_HANDLE_VALUE); |
| 470 | #endif |
| 471 | |
| 472 | s->pid = pid; |
| 473 | /* Set interactive/non-interactive mode. */ |
| 474 | packet_set_interactive(s->display != NULL, |
| 475 | options.ip_qos_interactive, options.ip_qos_bulk); |
| 476 | |
| 477 | /* |
| 478 | * Clear loginmsg, since it's the child's responsibility to display |
| 479 | * it to the user, otherwise multiple sessions may accumulate |
| 480 | * multiple copies of the login messages. |
| 481 | */ |
| 482 | buffer_clear(&loginmsg); |
| 483 | |
| 484 | #ifdef USE_PIPES |
| 485 | /* We are the parent. Close the child sides of the pipes. */ |
| 486 | close(pin[0]); |
| 487 | close(pout[1]); |
| 488 | close(perr[1]); |
| 489 | |
| 490 | session_set_fds(ssh, s, pin[1], pout[0], perr[0], |
| 491 | s->is_subsystem, 0); |
| 492 | #else |
| 493 | /* We are the parent. Close the child sides of the socket pairs. */ |
| 494 | close(inout[0]); |
| 495 | close(err[0]); |
| 496 | |
| 497 | /* |
| 498 | * Enter the interactive session. Note: server_loop must be able to |
| 499 | * handle the case that fdin and fdout are the same. |
| 500 | */ |
| 501 | session_set_fds(s, inout[1], inout[1], err[1], |
| 502 | s->is_subsystem, 0); |
| 503 | #endif |
| 504 | return 0; |
| 505 | } |
| 506 | |
| 507 | /* |
| 508 | * This is called to fork and execute a command when we have a tty. This |
| 509 | * will call do_child from the child, and server_loop from the parent after |
| 510 | * setting up file descriptors, controlling tty, updating wtmp, utmp, |
| 511 | * lastlog, and other such operations. |
| 512 | */ |
| 513 | int |
| 514 | do_exec_pty(struct ssh *ssh, Session *s, const char *command) |
| 515 | { |
| 516 | int fdout, ptyfd, ttyfd, ptymaster; |
| 517 | pid_t pid; |
| 518 | |
| 519 | if (s == NULL) |
| 520 | fatal("do_exec_pty: no session"); |
| 521 | ptyfd = s->ptyfd; |
| 522 | ttyfd = s->ttyfd; |
| 523 | |
| 524 | /* |
| 525 | * Create another descriptor of the pty master side for use as the |
| 526 | * standard input. We could use the original descriptor, but this |
| 527 | * simplifies code in server_loop. The descriptor is bidirectional. |
| 528 | * Do this before forking (and cleanup in the child) so as to |
| 529 | * detect and gracefully fail out-of-fd conditions. |
| 530 | */ |
| 531 | if ((fdout = dup(ptyfd)) < 0) { |
| 532 | error("%s: dup #1: %s", __func__, strerror(errno)); |
| 533 | close(ttyfd); |
| 534 | close(ptyfd); |
| 535 | return -1; |
| 536 | } |
| 537 | /* we keep a reference to the pty master */ |
| 538 | if ((ptymaster = dup(ptyfd)) < 0) { |
| 539 | error("%s: dup #2: %s", __func__, strerror(errno)); |
| 540 | close(ttyfd); |
| 541 | close(ptyfd); |
| 542 | close(fdout); |
| 543 | return -1; |
| 544 | } |
| 545 | |
| 546 | /* Fork the child. */ |
| 547 | switch ((pid = fork())) { |
| 548 | case -1: |
| 549 | error("%s: fork: %.100s", __func__, strerror(errno)); |
| 550 | close(fdout); |
| 551 | close(ptymaster); |
| 552 | close(ttyfd); |
| 553 | close(ptyfd); |
| 554 | return -1; |
| 555 | case 0: |
| 556 | is_child = 1; |
| 557 | |
| 558 | close(fdout); |
| 559 | close(ptymaster); |
| 560 | |
| 561 | /* Close the master side of the pseudo tty. */ |
| 562 | close(ptyfd); |
| 563 | |
| 564 | /* Make the pseudo tty our controlling tty. */ |
| 565 | pty_make_controlling_tty(&ttyfd, s->tty); |
| 566 | |
| 567 | /* Redirect stdin/stdout/stderr from the pseudo tty. */ |
| 568 | if (dup2(ttyfd, 0) < 0) |
| 569 | error("dup2 stdin: %s", strerror(errno)); |
| 570 | if (dup2(ttyfd, 1) < 0) |
| 571 | error("dup2 stdout: %s", strerror(errno)); |
| 572 | if (dup2(ttyfd, 2) < 0) |
| 573 | error("dup2 stderr: %s", strerror(errno)); |
| 574 | |
| 575 | /* Close the extra descriptor for the pseudo tty. */ |
| 576 | close(ttyfd); |
| 577 | |
| 578 | /* record login, etc. similar to login(1) */ |
| 579 | #ifdef _UNICOS |
| 580 | cray_init_job(s->pw); /* set up cray jid and tmpdir */ |
| 581 | #endif /* _UNICOS */ |
| 582 | #ifndef HAVE_OSF_SIA |
| 583 | do_login(ssh, s, command); |
| 584 | #endif |
| 585 | /* |
| 586 | * Do common processing for the child, such as execing |
| 587 | * the command. |
| 588 | */ |
| 589 | do_child(ssh, s, command); |
| 590 | /* NOTREACHED */ |
| 591 | default: |
| 592 | break; |
| 593 | } |
| 594 | |
| 595 | #ifdef _UNICOS |
| 596 | signal(WJSIGNAL, cray_job_termination_handler); |
| 597 | #endif /* _UNICOS */ |
| 598 | #ifdef HAVE_CYGWIN |
| 599 | cygwin_set_impersonation_token(INVALID_HANDLE_VALUE); |
| 600 | #endif |
| 601 | |
| 602 | s->pid = pid; |
| 603 | |
| 604 | /* Parent. Close the slave side of the pseudo tty. */ |
| 605 | close(ttyfd); |
| 606 | |
| 607 | /* Enter interactive session. */ |
| 608 | s->ptymaster = ptymaster; |
| 609 | packet_set_interactive(1, |
| 610 | options.ip_qos_interactive, options.ip_qos_bulk); |
| 611 | session_set_fds(ssh, s, ptyfd, fdout, -1, 1, 1); |
| 612 | return 0; |
| 613 | } |
| 614 | |
| 615 | #ifdef LOGIN_NEEDS_UTMPX |
| 616 | static void |
| 617 | do_pre_login(Session *s) |
| 618 | { |
| 619 | struct ssh *ssh = active_state; /* XXX */ |
| 620 | socklen_t fromlen; |
| 621 | struct sockaddr_storage from; |
| 622 | pid_t pid = getpid(); |
| 623 | |
| 624 | /* |
| 625 | * Get IP address of client. If the connection is not a socket, let |
| 626 | * the address be 0.0.0.0. |
| 627 | */ |
| 628 | memset(&from, 0, sizeof(from)); |
| 629 | fromlen = sizeof(from); |
| 630 | if (packet_connection_is_on_socket()) { |
| 631 | if (getpeername(packet_get_connection_in(), |
| 632 | (struct sockaddr *)&from, &fromlen) < 0) { |
| 633 | debug("getpeername: %.100s", strerror(errno)); |
| 634 | cleanup_exit(255); |
| 635 | } |
| 636 | } |
| 637 | |
| 638 | record_utmp_only(pid, s->tty, s->pw->pw_name, |
| 639 | session_get_remote_name_or_ip(ssh, utmp_len, options.use_dns), |
| 640 | (struct sockaddr *)&from, fromlen); |
| 641 | } |
| 642 | #endif |
| 643 | |
| 644 | /* |
| 645 | * This is called to fork and execute a command. If another command is |
| 646 | * to be forced, execute that instead. |
| 647 | */ |
| 648 | int |
| 649 | do_exec(struct ssh *ssh, Session *s, const char *command) |
| 650 | { |
| 651 | int ret; |
| 652 | const char *forced = NULL, *tty = NULL; |
| 653 | char session_type[1024]; |
| 654 | |
| 655 | if (options.adm_forced_command) { |
| 656 | original_command = command; |
| 657 | command = options.adm_forced_command; |
| 658 | forced = "(config)"; |
| 659 | } else if (forced_command) { |
| 660 | original_command = command; |
| 661 | command = forced_command; |
| 662 | forced = "(key-option)"; |
| 663 | } |
| 664 | if (forced != NULL) { |
| 665 | if (IS_INTERNAL_SFTP(command)) { |
| 666 | s->is_subsystem = s->is_subsystem ? |
| 667 | SUBSYSTEM_INT_SFTP : SUBSYSTEM_INT_SFTP_ERROR; |
| 668 | } else if (s->is_subsystem) |
| 669 | s->is_subsystem = SUBSYSTEM_EXT; |
| 670 | snprintf(session_type, sizeof(session_type), |
| 671 | "forced-command %s '%.900s'", forced, command); |
| 672 | } else if (s->is_subsystem) { |
| 673 | snprintf(session_type, sizeof(session_type), |
| 674 | "subsystem '%.900s'", s->subsys); |
| 675 | } else if (command == NULL) { |
| 676 | snprintf(session_type, sizeof(session_type), "shell"); |
| 677 | } else { |
| 678 | /* NB. we don't log unforced commands to preserve privacy */ |
| 679 | snprintf(session_type, sizeof(session_type), "command"); |
| 680 | } |
| 681 | |
| 682 | if (s->ttyfd != -1) { |
| 683 | tty = s->tty; |
| 684 | if (strncmp(tty, "/dev/", 5) == 0) |
| 685 | tty += 5; |
| 686 | } |
| 687 | |
| 688 | verbose("Starting session: %s%s%s for %s from %.200s port %d id %d", |
| 689 | session_type, |
| 690 | tty == NULL ? "" : " on ", |
| 691 | tty == NULL ? "" : tty, |
| 692 | s->pw->pw_name, |
| 693 | ssh_remote_ipaddr(ssh), |
| 694 | ssh_remote_port(ssh), |
| 695 | s->self); |
| 696 | |
| 697 | #ifdef SSH_AUDIT_EVENTS |
| 698 | if (command != NULL) |
| 699 | PRIVSEP(audit_run_command(command)); |
| 700 | else if (s->ttyfd == -1) { |
| 701 | char *shell = s->pw->pw_shell; |
| 702 | |
| 703 | if (shell[0] == '\0') /* empty shell means /bin/sh */ |
| 704 | shell =_PATH_BSHELL; |
| 705 | PRIVSEP(audit_run_command(shell)); |
| 706 | } |
| 707 | #endif |
| 708 | if (s->ttyfd != -1) |
| 709 | ret = do_exec_pty(ssh, s, command); |
| 710 | else |
| 711 | ret = do_exec_no_pty(ssh, s, command); |
| 712 | |
| 713 | original_command = NULL; |
| 714 | |
| 715 | /* |
| 716 | * Clear loginmsg: it's the child's responsibility to display |
| 717 | * it to the user, otherwise multiple sessions may accumulate |
| 718 | * multiple copies of the login messages. |
| 719 | */ |
| 720 | buffer_clear(&loginmsg); |
| 721 | |
| 722 | return ret; |
| 723 | } |
| 724 | |
| 725 | /* administrative, login(1)-like work */ |
| 726 | void |
| 727 | do_login(struct ssh *ssh, Session *s, const char *command) |
| 728 | { |
| 729 | socklen_t fromlen; |
| 730 | struct sockaddr_storage from; |
| 731 | struct passwd * pw = s->pw; |
| 732 | pid_t pid = getpid(); |
| 733 | |
| 734 | /* |
| 735 | * Get IP address of client. If the connection is not a socket, let |
| 736 | * the address be 0.0.0.0. |
| 737 | */ |
| 738 | memset(&from, 0, sizeof(from)); |
| 739 | fromlen = sizeof(from); |
| 740 | if (packet_connection_is_on_socket()) { |
| 741 | if (getpeername(packet_get_connection_in(), |
| 742 | (struct sockaddr *)&from, &fromlen) < 0) { |
| 743 | debug("getpeername: %.100s", strerror(errno)); |
| 744 | cleanup_exit(255); |
| 745 | } |
| 746 | } |
| 747 | |
| 748 | /* Record that there was a login on that tty from the remote host. */ |
| 749 | if (!use_privsep) |
| 750 | record_login(pid, s->tty, pw->pw_name, pw->pw_uid, |
| 751 | session_get_remote_name_or_ip(ssh, utmp_len, |
| 752 | options.use_dns), |
| 753 | (struct sockaddr *)&from, fromlen); |
| 754 | |
| 755 | #ifdef USE_PAM |
| 756 | /* |
| 757 | * If password change is needed, do it now. |
| 758 | * This needs to occur before the ~/.hushlogin check. |
| 759 | */ |
| 760 | if (options.use_pam && !use_privsep && s->authctxt->force_pwchange) { |
| 761 | display_loginmsg(); |
| 762 | do_pam_chauthtok(); |
| 763 | s->authctxt->force_pwchange = 0; |
| 764 | /* XXX - signal [net] parent to enable forwardings */ |
| 765 | } |
| 766 | #endif |
| 767 | |
| 768 | if (check_quietlogin(s, command)) |
| 769 | return; |
| 770 | |
| 771 | display_loginmsg(); |
| 772 | |
| 773 | do_motd(); |
| 774 | } |
| 775 | |
| 776 | /* |
| 777 | * Display the message of the day. |
| 778 | */ |
| 779 | void |
| 780 | do_motd(void) |
| 781 | { |
| 782 | FILE *f; |
| 783 | char buf[256]; |
| 784 | |
| 785 | if (options.print_motd) { |
| 786 | #ifdef HAVE_LOGIN_CAP |
| 787 | f = fopen(login_getcapstr(lc, "welcome", "/etc/motd", |
| 788 | "/etc/motd"), "r"); |
| 789 | #else |
| 790 | f = fopen("/etc/motd", "r"); |
| 791 | #endif |
| 792 | if (f) { |
| 793 | while (fgets(buf, sizeof(buf), f)) |
| 794 | fputs(buf, stdout); |
| 795 | fclose(f); |
| 796 | } |
| 797 | } |
| 798 | } |
| 799 | |
| 800 | |
| 801 | /* |
| 802 | * Check for quiet login, either .hushlogin or command given. |
| 803 | */ |
| 804 | int |
| 805 | check_quietlogin(Session *s, const char *command) |
| 806 | { |
| 807 | char buf[256]; |
| 808 | struct passwd *pw = s->pw; |
| 809 | struct stat st; |
| 810 | |
| 811 | /* Return 1 if .hushlogin exists or a command given. */ |
| 812 | if (command != NULL) |
| 813 | return 1; |
| 814 | snprintf(buf, sizeof(buf), "%.200s/.hushlogin", pw->pw_dir); |
| 815 | #ifdef HAVE_LOGIN_CAP |
| 816 | if (login_getcapbool(lc, "hushlogin", 0) || stat(buf, &st) >= 0) |
| 817 | return 1; |
| 818 | #else |
| 819 | if (stat(buf, &st) >= 0) |
| 820 | return 1; |
| 821 | #endif |
| 822 | return 0; |
| 823 | } |
| 824 | |
| 825 | /* |
| 826 | * Reads environment variables from the given file and adds/overrides them |
| 827 | * into the environment. If the file does not exist, this does nothing. |
| 828 | * Otherwise, it must consist of empty lines, comments (line starts with '#') |
| 829 | * and assignments of the form name=value. No other forms are allowed. |
| 830 | */ |
| 831 | static void |
| 832 | read_environment_file(char ***env, u_int *envsize, |
| 833 | const char *filename) |
| 834 | { |
| 835 | FILE *f; |
| 836 | char buf[4096]; |
| 837 | char *cp, *value; |
| 838 | u_int lineno = 0; |
| 839 | |
| 840 | f = fopen(filename, "r"); |
| 841 | if (!f) |
| 842 | return; |
| 843 | |
| 844 | while (fgets(buf, sizeof(buf), f)) { |
| 845 | if (++lineno > 1000) |
| 846 | fatal("Too many lines in environment file %s", filename); |
| 847 | for (cp = buf; *cp == ' ' || *cp == '\t'; cp++) |
| 848 | ; |
| 849 | if (!*cp || *cp == '#' || *cp == '\n') |
| 850 | continue; |
| 851 | |
| 852 | cp[strcspn(cp, "\n")] = '\0'; |
| 853 | |
| 854 | value = strchr(cp, '='); |
| 855 | if (value == NULL) { |
| 856 | fprintf(stderr, "Bad line %u in %.100s\n", lineno, |
| 857 | filename); |
| 858 | continue; |
| 859 | } |
| 860 | /* |
| 861 | * Replace the equals sign by nul, and advance value to |
| 862 | * the value string. |
| 863 | */ |
| 864 | *value = '\0'; |
| 865 | value++; |
| 866 | child_set_env(env, envsize, cp, value); |
| 867 | } |
| 868 | fclose(f); |
| 869 | } |
| 870 | |
| 871 | #ifdef HAVE_ETC_DEFAULT_LOGIN |
| 872 | /* |
| 873 | * Return named variable from specified environment, or NULL if not present. |
| 874 | */ |
| 875 | static char * |
| 876 | child_get_env(char **env, const char *name) |
| 877 | { |
| 878 | int i; |
| 879 | size_t len; |
| 880 | |
| 881 | len = strlen(name); |
| 882 | for (i=0; env[i] != NULL; i++) |
| 883 | if (strncmp(name, env[i], len) == 0 && env[i][len] == '=') |
| 884 | return(env[i] + len + 1); |
| 885 | return NULL; |
| 886 | } |
| 887 | |
| 888 | /* |
| 889 | * Read /etc/default/login. |
| 890 | * We pick up the PATH (or SUPATH for root) and UMASK. |
| 891 | */ |
| 892 | static void |
| 893 | read_etc_default_login(char ***env, u_int *envsize, uid_t uid) |
| 894 | { |
| 895 | char **tmpenv = NULL, *var; |
| 896 | u_int i, tmpenvsize = 0; |
| 897 | u_long mask; |
| 898 | |
| 899 | /* |
| 900 | * We don't want to copy the whole file to the child's environment, |
| 901 | * so we use a temporary environment and copy the variables we're |
| 902 | * interested in. |
| 903 | */ |
| 904 | read_environment_file(&tmpenv, &tmpenvsize, "/etc/default/login"); |
| 905 | |
| 906 | if (tmpenv == NULL) |
| 907 | return; |
| 908 | |
| 909 | if (uid == 0) |
| 910 | var = child_get_env(tmpenv, "SUPATH"); |
| 911 | else |
| 912 | var = child_get_env(tmpenv, "PATH"); |
| 913 | if (var != NULL) |
| 914 | child_set_env(env, envsize, "PATH", var); |
| 915 | |
| 916 | if ((var = child_get_env(tmpenv, "UMASK")) != NULL) |
| 917 | if (sscanf(var, "%5lo", &mask) == 1) |
| 918 | umask((mode_t)mask); |
| 919 | |
| 920 | for (i = 0; tmpenv[i] != NULL; i++) |
| 921 | free(tmpenv[i]); |
| 922 | free(tmpenv); |
| 923 | } |
| 924 | #endif /* HAVE_ETC_DEFAULT_LOGIN */ |
| 925 | |
| 926 | static void |
| 927 | copy_environment_blacklist(char **source, char ***env, u_int *envsize, |
| 928 | const char *blacklist) |
| 929 | { |
| 930 | char *var_name, *var_val; |
| 931 | int i; |
| 932 | |
| 933 | if (source == NULL) |
| 934 | return; |
| 935 | |
| 936 | for(i = 0; source[i] != NULL; i++) { |
| 937 | var_name = xstrdup(source[i]); |
| 938 | if ((var_val = strstr(var_name, "=")) == NULL) { |
| 939 | free(var_name); |
| 940 | continue; |
| 941 | } |
| 942 | *var_val++ = '\0'; |
| 943 | |
| 944 | if (blacklist == NULL || |
| 945 | match_pattern_list(var_name, blacklist, 0) != 1) { |
| 946 | debug3("Copy environment: %s=%s", var_name, var_val); |
| 947 | child_set_env(env, envsize, var_name, var_val); |
| 948 | } |
| 949 | |
| 950 | free(var_name); |
| 951 | } |
| 952 | } |
| 953 | |
| 954 | #ifdef HAVE_CYGWIN |
| 955 | |
| 956 | static void |
| 957 | copy_environment(char **source, char ***env, u_int *envsize) |
| 958 | { |
| 959 | copy_environment_blacklist(source, env, envsize, NULL); |
| 960 | } |
| 961 | |
| 962 | #endif |
| 963 | |
| 964 | static char ** |
| 965 | do_setup_env(struct ssh *ssh, Session *s, const char *shell) |
| 966 | { |
| 967 | char buf[256]; |
| 968 | u_int i, envsize; |
| 969 | char **env, *laddr; |
| 970 | struct passwd *pw = s->pw; |
| 971 | #if !defined (HAVE_LOGIN_CAP) && !defined (HAVE_CYGWIN) |
| 972 | char *path = NULL; |
| 973 | #endif |
| 974 | |
| 975 | /* Initialize the environment. */ |
| 976 | envsize = 100; |
| 977 | env = xcalloc(envsize, sizeof(char *)); |
| 978 | env[0] = NULL; |
| 979 | |
| 980 | #ifdef HAVE_CYGWIN |
| 981 | /* |
| 982 | * The Windows environment contains some setting which are |
| 983 | * important for a running system. They must not be dropped. |
| 984 | */ |
| 985 | { |
| 986 | char **p; |
| 987 | |
| 988 | p = fetch_windows_environment(); |
| 989 | copy_environment(p, &env, &envsize); |
| 990 | free_windows_environment(p); |
| 991 | } |
| 992 | #endif |
| 993 | |
| 994 | #ifdef GSSAPI |
| 995 | /* Allow any GSSAPI methods that we've used to alter |
| 996 | * the childs environment as they see fit |
| 997 | */ |
| 998 | ssh_gssapi_do_child(&env, &envsize); |
| 999 | #endif |
| 1000 | |
| 1001 | /* Set basic environment. */ |
| 1002 | for (i = 0; i < s->num_env; i++) |
| 1003 | child_set_env(&env, &envsize, s->env[i].name, s->env[i].val); |
| 1004 | |
| 1005 | child_set_env(&env, &envsize, "USER", pw->pw_name); |
| 1006 | child_set_env(&env, &envsize, "LOGNAME", pw->pw_name); |
| 1007 | #ifdef _AIX |
| 1008 | child_set_env(&env, &envsize, "LOGIN", pw->pw_name); |
| 1009 | #endif |
| 1010 | child_set_env(&env, &envsize, "HOME", pw->pw_dir); |
| 1011 | #ifdef HAVE_LOGIN_CAP |
| 1012 | if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETPATH) < 0) |
| 1013 | child_set_env(&env, &envsize, "PATH", _PATH_STDPATH); |
| 1014 | else |
| 1015 | child_set_env(&env, &envsize, "PATH", getenv("PATH")); |
| 1016 | #else /* HAVE_LOGIN_CAP */ |
| 1017 | # ifndef HAVE_CYGWIN |
| 1018 | /* |
| 1019 | * There's no standard path on Windows. The path contains |
| 1020 | * important components pointing to the system directories, |
| 1021 | * needed for loading shared libraries. So the path better |
| 1022 | * remains intact here. |
| 1023 | */ |
| 1024 | # ifdef HAVE_ETC_DEFAULT_LOGIN |
| 1025 | read_etc_default_login(&env, &envsize, pw->pw_uid); |
| 1026 | path = child_get_env(env, "PATH"); |
| 1027 | # endif /* HAVE_ETC_DEFAULT_LOGIN */ |
| 1028 | if (path == NULL || *path == '\0') { |
| 1029 | child_set_env(&env, &envsize, "PATH", |
| 1030 | s->pw->pw_uid == 0 ? SUPERUSER_PATH : _PATH_STDPATH); |
| 1031 | } |
| 1032 | # endif /* HAVE_CYGWIN */ |
| 1033 | #endif /* HAVE_LOGIN_CAP */ |
| 1034 | |
| 1035 | snprintf(buf, sizeof buf, "%.200s/%.50s", _PATH_MAILDIR, pw->pw_name); |
| 1036 | child_set_env(&env, &envsize, "MAIL", buf); |
| 1037 | |
| 1038 | /* Normal systems set SHELL by default. */ |
| 1039 | child_set_env(&env, &envsize, "SHELL", shell); |
| 1040 | |
| 1041 | if (getenv("TZ")) |
| 1042 | child_set_env(&env, &envsize, "TZ", getenv("TZ")); |
| 1043 | |
| 1044 | /* Set custom environment options from RSA authentication. */ |
| 1045 | while (custom_environment) { |
| 1046 | struct envstring *ce = custom_environment; |
| 1047 | char *str = ce->s; |
| 1048 | |
| 1049 | for (i = 0; str[i] != '=' && str[i]; i++) |
| 1050 | ; |
| 1051 | if (str[i] == '=') { |
| 1052 | str[i] = 0; |
| 1053 | child_set_env(&env, &envsize, str, str + i + 1); |
| 1054 | } |
| 1055 | custom_environment = ce->next; |
| 1056 | free(ce->s); |
| 1057 | free(ce); |
| 1058 | } |
| 1059 | |
| 1060 | /* SSH_CLIENT deprecated */ |
| 1061 | snprintf(buf, sizeof buf, "%.50s %d %d", |
| 1062 | ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), |
| 1063 | ssh_local_port(ssh)); |
| 1064 | child_set_env(&env, &envsize, "SSH_CLIENT", buf); |
| 1065 | |
| 1066 | laddr = get_local_ipaddr(packet_get_connection_in()); |
| 1067 | snprintf(buf, sizeof buf, "%.50s %d %.50s %d", |
| 1068 | ssh_remote_ipaddr(ssh), ssh_remote_port(ssh), |
| 1069 | laddr, ssh_local_port(ssh)); |
| 1070 | free(laddr); |
| 1071 | child_set_env(&env, &envsize, "SSH_CONNECTION", buf); |
| 1072 | |
| 1073 | if (auth_info_file != NULL) |
| 1074 | child_set_env(&env, &envsize, "SSH_USER_AUTH", auth_info_file); |
| 1075 | if (s->ttyfd != -1) |
| 1076 | child_set_env(&env, &envsize, "SSH_TTY", s->tty); |
| 1077 | if (s->term) |
| 1078 | child_set_env(&env, &envsize, "TERM", s->term); |
| 1079 | if (s->display) |
| 1080 | child_set_env(&env, &envsize, "DISPLAY", s->display); |
| 1081 | if (original_command) |
| 1082 | child_set_env(&env, &envsize, "SSH_ORIGINAL_COMMAND", |
| 1083 | original_command); |
| 1084 | |
| 1085 | #ifdef _UNICOS |
| 1086 | if (cray_tmpdir[0] != '\0') |
| 1087 | child_set_env(&env, &envsize, "TMPDIR", cray_tmpdir); |
| 1088 | #endif /* _UNICOS */ |
| 1089 | |
| 1090 | /* |
| 1091 | * Since we clear KRB5CCNAME at startup, if it's set now then it |
| 1092 | * must have been set by a native authentication method (eg AIX or |
| 1093 | * SIA), so copy it to the child. |
| 1094 | */ |
| 1095 | { |
| 1096 | char *cp; |
| 1097 | |
| 1098 | if ((cp = getenv("KRB5CCNAME")) != NULL) |
| 1099 | child_set_env(&env, &envsize, "KRB5CCNAME", cp); |
| 1100 | } |
| 1101 | |
| 1102 | #ifdef _AIX |
| 1103 | { |
| 1104 | char *cp; |
| 1105 | |
| 1106 | if ((cp = getenv("AUTHSTATE")) != NULL) |
| 1107 | child_set_env(&env, &envsize, "AUTHSTATE", cp); |
| 1108 | read_environment_file(&env, &envsize, "/etc/environment"); |
| 1109 | } |
| 1110 | #endif |
| 1111 | #ifdef KRB5 |
| 1112 | if (s->authctxt->krb5_ccname) |
| 1113 | child_set_env(&env, &envsize, "KRB5CCNAME", |
| 1114 | s->authctxt->krb5_ccname); |
| 1115 | #endif |
| 1116 | #ifdef USE_PAM |
| 1117 | /* |
| 1118 | * Pull in any environment variables that may have |
| 1119 | * been set by PAM. |
| 1120 | */ |
| 1121 | if (options.use_pam) { |
| 1122 | char **p; |
| 1123 | |
| 1124 | /* |
| 1125 | * Don't allow SSH_AUTH_INFO variables posted to PAM to leak |
| 1126 | * back into the environment. |
| 1127 | */ |
| 1128 | p = fetch_pam_child_environment(); |
| 1129 | copy_environment_blacklist(p, &env, &envsize, "SSH_AUTH_INFO*"); |
| 1130 | free_pam_environment(p); |
| 1131 | |
| 1132 | p = fetch_pam_environment(); |
| 1133 | copy_environment_blacklist(p, &env, &envsize, "SSH_AUTH_INFO*"); |
| 1134 | free_pam_environment(p); |
| 1135 | } |
| 1136 | #endif /* USE_PAM */ |
| 1137 | |
| 1138 | if (auth_sock_name != NULL) |
| 1139 | child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME, |
| 1140 | auth_sock_name); |
| 1141 | |
| 1142 | /* read $HOME/.ssh/environment. */ |
| 1143 | if (options.permit_user_env) { |
| 1144 | snprintf(buf, sizeof buf, "%.200s/.ssh/environment", |
| 1145 | strcmp(pw->pw_dir, "/") ? pw->pw_dir : ""); |
| 1146 | read_environment_file(&env, &envsize, buf); |
| 1147 | } |
| 1148 | if (debug_flag) { |
| 1149 | /* dump the environment */ |
| 1150 | fprintf(stderr, "Environment:\n"); |
| 1151 | for (i = 0; env[i]; i++) |
| 1152 | fprintf(stderr, " %.200s\n", env[i]); |
| 1153 | } |
| 1154 | return env; |
| 1155 | } |
| 1156 | |
| 1157 | /* |
| 1158 | * Run $HOME/.ssh/rc, /etc/ssh/sshrc, or xauth (whichever is found |
| 1159 | * first in this order). |
| 1160 | */ |
| 1161 | static void |
| 1162 | do_rc_files(Session *s, const char *shell) |
| 1163 | { |
| 1164 | FILE *f = NULL; |
| 1165 | char cmd[1024]; |
| 1166 | int do_xauth; |
| 1167 | struct stat st; |
| 1168 | |
| 1169 | do_xauth = |
| 1170 | s->display != NULL && s->auth_proto != NULL && s->auth_data != NULL; |
| 1171 | |
| 1172 | /* ignore _PATH_SSH_USER_RC for subsystems and admin forced commands */ |
| 1173 | if (!s->is_subsystem && options.adm_forced_command == NULL && |
| 1174 | !no_user_rc && options.permit_user_rc && |
| 1175 | stat(_PATH_SSH_USER_RC, &st) >= 0) { |
| 1176 | snprintf(cmd, sizeof cmd, "%s -c '%s %s'", |
| 1177 | shell, _PATH_BSHELL, _PATH_SSH_USER_RC); |
| 1178 | if (debug_flag) |
| 1179 | fprintf(stderr, "Running %s\n", cmd); |
| 1180 | f = popen(cmd, "w"); |
| 1181 | if (f) { |
| 1182 | if (do_xauth) |
| 1183 | fprintf(f, "%s %s\n", s->auth_proto, |
| 1184 | s->auth_data); |
| 1185 | pclose(f); |
| 1186 | } else |
| 1187 | fprintf(stderr, "Could not run %s\n", |
| 1188 | _PATH_SSH_USER_RC); |
| 1189 | } else if (stat(_PATH_SSH_SYSTEM_RC, &st) >= 0) { |
| 1190 | if (debug_flag) |
| 1191 | fprintf(stderr, "Running %s %s\n", _PATH_BSHELL, |
| 1192 | _PATH_SSH_SYSTEM_RC); |
| 1193 | f = popen(_PATH_BSHELL " " _PATH_SSH_SYSTEM_RC, "w"); |
| 1194 | if (f) { |
| 1195 | if (do_xauth) |
| 1196 | fprintf(f, "%s %s\n", s->auth_proto, |
| 1197 | s->auth_data); |
| 1198 | pclose(f); |
| 1199 | } else |
| 1200 | fprintf(stderr, "Could not run %s\n", |
| 1201 | _PATH_SSH_SYSTEM_RC); |
| 1202 | } else if (do_xauth && options.xauth_location != NULL) { |
| 1203 | /* Add authority data to .Xauthority if appropriate. */ |
| 1204 | if (debug_flag) { |
| 1205 | fprintf(stderr, |
| 1206 | "Running %.500s remove %.100s\n", |
| 1207 | options.xauth_location, s->auth_display); |
| 1208 | fprintf(stderr, |
| 1209 | "%.500s add %.100s %.100s %.100s\n", |
| 1210 | options.xauth_location, s->auth_display, |
| 1211 | s->auth_proto, s->auth_data); |
| 1212 | } |
| 1213 | snprintf(cmd, sizeof cmd, "%s -q -", |
| 1214 | options.xauth_location); |
| 1215 | f = popen(cmd, "w"); |
| 1216 | if (f) { |
| 1217 | fprintf(f, "remove %s\n", |
| 1218 | s->auth_display); |
| 1219 | fprintf(f, "add %s %s %s\n", |
| 1220 | s->auth_display, s->auth_proto, |
| 1221 | s->auth_data); |
| 1222 | pclose(f); |
| 1223 | } else { |
| 1224 | fprintf(stderr, "Could not run %s\n", |
| 1225 | cmd); |
| 1226 | } |
| 1227 | } |
| 1228 | } |
| 1229 | |
| 1230 | static void |
| 1231 | do_nologin(struct passwd *pw) |
| 1232 | { |
| 1233 | FILE *f = NULL; |
| 1234 | char buf[1024], *nl, *def_nl = _PATH_NOLOGIN; |
| 1235 | struct stat sb; |
| 1236 | |
| 1237 | #ifdef HAVE_LOGIN_CAP |
| 1238 | if (login_getcapbool(lc, "ignorenologin", 0) || pw->pw_uid == 0) |
| 1239 | return; |
| 1240 | nl = login_getcapstr(lc, "nologin", def_nl, def_nl); |
| 1241 | #else |
| 1242 | if (pw->pw_uid == 0) |
| 1243 | return; |
| 1244 | nl = def_nl; |
| 1245 | #endif |
| 1246 | if (stat(nl, &sb) == -1) { |
| 1247 | if (nl != def_nl) |
| 1248 | free(nl); |
| 1249 | return; |
| 1250 | } |
| 1251 | |
| 1252 | /* /etc/nologin exists. Print its contents if we can and exit. */ |
| 1253 | logit("User %.100s not allowed because %s exists", pw->pw_name, nl); |
| 1254 | if ((f = fopen(nl, "r")) != NULL) { |
| 1255 | while (fgets(buf, sizeof(buf), f)) |
| 1256 | fputs(buf, stderr); |
| 1257 | fclose(f); |
| 1258 | } |
| 1259 | exit(254); |
| 1260 | } |
| 1261 | |
| 1262 | /* |
| 1263 | * Chroot into a directory after checking it for safety: all path components |
| 1264 | * must be root-owned directories with strict permissions. |
| 1265 | */ |
| 1266 | static void |
| 1267 | safely_chroot(const char *path, uid_t uid) |
| 1268 | { |
| 1269 | const char *cp; |
| 1270 | char component[PATH_MAX]; |
| 1271 | struct stat st; |
| 1272 | |
| 1273 | if (*path != '/') |
| 1274 | fatal("chroot path does not begin at root"); |
| 1275 | if (strlen(path) >= sizeof(component)) |
| 1276 | fatal("chroot path too long"); |
| 1277 | |
| 1278 | /* |
| 1279 | * Descend the path, checking that each component is a |
| 1280 | * root-owned directory with strict permissions. |
| 1281 | */ |
| 1282 | for (cp = path; cp != NULL;) { |
| 1283 | if ((cp = strchr(cp, '/')) == NULL) |
| 1284 | strlcpy(component, path, sizeof(component)); |
| 1285 | else { |
| 1286 | cp++; |
| 1287 | memcpy(component, path, cp - path); |
| 1288 | component[cp - path] = '\0'; |
| 1289 | } |
| 1290 | |
| 1291 | debug3("%s: checking '%s'", __func__, component); |
| 1292 | |
| 1293 | if (stat(component, &st) != 0) |
| 1294 | fatal("%s: stat(\"%s\"): %s", __func__, |
| 1295 | component, strerror(errno)); |
| 1296 | if (st.st_uid != 0 || (st.st_mode & 022) != 0) |
| 1297 | fatal("bad ownership or modes for chroot " |
| 1298 | "directory %s\"%s\"", |
| 1299 | cp == NULL ? "" : "component ", component); |
| 1300 | if (!S_ISDIR(st.st_mode)) |
| 1301 | fatal("chroot path %s\"%s\" is not a directory", |
| 1302 | cp == NULL ? "" : "component ", component); |
| 1303 | |
| 1304 | } |
| 1305 | |
| 1306 | if (chdir(path) == -1) |
| 1307 | fatal("Unable to chdir to chroot path \"%s\": " |
| 1308 | "%s", path, strerror(errno)); |
| 1309 | if (chroot(path) == -1) |
| 1310 | fatal("chroot(\"%s\"): %s", path, strerror(errno)); |
| 1311 | if (chdir("/") == -1) |
| 1312 | fatal("%s: chdir(/) after chroot: %s", |
| 1313 | __func__, strerror(errno)); |
| 1314 | verbose("Changed root directory to \"%s\"", path); |
| 1315 | } |
| 1316 | |
| 1317 | /* Set login name, uid, gid, and groups. */ |
| 1318 | void |
| 1319 | do_setusercontext(struct passwd *pw) |
| 1320 | { |
| 1321 | char *chroot_path, *tmp; |
| 1322 | |
| 1323 | platform_setusercontext(pw); |
| 1324 | |
| 1325 | if (platform_privileged_uidswap()) { |
| 1326 | #ifdef HAVE_LOGIN_CAP |
| 1327 | if (setusercontext(lc, pw, pw->pw_uid, |
| 1328 | (LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETUSER))) < 0) { |
| 1329 | perror("unable to set user context"); |
| 1330 | exit(1); |
| 1331 | } |
| 1332 | #else |
| 1333 | if (setlogin(pw->pw_name) < 0) |
| 1334 | error("setlogin failed: %s", strerror(errno)); |
| 1335 | if (setgid(pw->pw_gid) < 0) { |
| 1336 | perror("setgid"); |
| 1337 | exit(1); |
| 1338 | } |
| 1339 | /* Initialize the group list. */ |
| 1340 | if (initgroups(pw->pw_name, pw->pw_gid) < 0) { |
| 1341 | perror("initgroups"); |
| 1342 | exit(1); |
| 1343 | } |
| 1344 | endgrent(); |
| 1345 | #endif |
| 1346 | |
| 1347 | platform_setusercontext_post_groups(pw); |
| 1348 | |
| 1349 | if (!in_chroot && options.chroot_directory != NULL && |
| 1350 | strcasecmp(options.chroot_directory, "none") != 0) { |
| 1351 | tmp = tilde_expand_filename(options.chroot_directory, |
| 1352 | pw->pw_uid); |
| 1353 | chroot_path = percent_expand(tmp, "h", pw->pw_dir, |
| 1354 | "u", pw->pw_name, (char *)NULL); |
| 1355 | safely_chroot(chroot_path, pw->pw_uid); |
| 1356 | free(tmp); |
| 1357 | free(chroot_path); |
| 1358 | /* Make sure we don't attempt to chroot again */ |
| 1359 | free(options.chroot_directory); |
| 1360 | options.chroot_directory = NULL; |
| 1361 | in_chroot = 1; |
| 1362 | } |
| 1363 | |
| 1364 | #ifdef HAVE_LOGIN_CAP |
| 1365 | if (setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUSER) < 0) { |
| 1366 | perror("unable to set user context (setuser)"); |
| 1367 | exit(1); |
| 1368 | } |
| 1369 | /* |
| 1370 | * FreeBSD's setusercontext() will not apply the user's |
| 1371 | * own umask setting unless running with the user's UID. |
| 1372 | */ |
| 1373 | (void) setusercontext(lc, pw, pw->pw_uid, LOGIN_SETUMASK); |
| 1374 | #else |
| 1375 | # ifdef USE_LIBIAF |
| 1376 | /* |
| 1377 | * In a chroot environment, the set_id() will always fail; |
| 1378 | * typically because of the lack of necessary authentication |
| 1379 | * services and runtime such as ./usr/lib/libiaf.so, |
| 1380 | * ./usr/lib/libpam.so.1, and ./etc/passwd We skip it in the |
| 1381 | * internal sftp chroot case. We'll lose auditing and ACLs but |
| 1382 | * permanently_set_uid will take care of the rest. |
| 1383 | */ |
| 1384 | if (!in_chroot && set_id(pw->pw_name) != 0) |
| 1385 | fatal("set_id(%s) Failed", pw->pw_name); |
| 1386 | # endif /* USE_LIBIAF */ |
| 1387 | /* Permanently switch to the desired uid. */ |
| 1388 | permanently_set_uid(pw); |
| 1389 | #endif |
| 1390 | } else if (options.chroot_directory != NULL && |
| 1391 | strcasecmp(options.chroot_directory, "none") != 0) { |
| 1392 | fatal("server lacks privileges to chroot to ChrootDirectory"); |
| 1393 | } |
| 1394 | |
| 1395 | if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid) |
| 1396 | fatal("Failed to set uids to %u.", (u_int) pw->pw_uid); |
| 1397 | } |
| 1398 | |
| 1399 | static void |
| 1400 | do_pwchange(Session *s) |
| 1401 | { |
| 1402 | fflush(NULL); |
| 1403 | fprintf(stderr, "WARNING: Your password has expired.\n"); |
| 1404 | if (s->ttyfd != -1) { |
| 1405 | fprintf(stderr, |
| 1406 | "You must change your password now and login again!\n"); |
| 1407 | #ifdef WITH_SELINUX |
| 1408 | setexeccon(NULL); |
| 1409 | #endif |
| 1410 | #ifdef PASSWD_NEEDS_USERNAME |
| 1411 | execl(_PATH_PASSWD_PROG, "passwd", s->pw->pw_name, |
| 1412 | (char *)NULL); |
| 1413 | #else |
| 1414 | execl(_PATH_PASSWD_PROG, "passwd", (char *)NULL); |
| 1415 | #endif |
| 1416 | perror("passwd"); |
| 1417 | } else { |
| 1418 | fprintf(stderr, |
| 1419 | "Password change required but no TTY available.\n"); |
| 1420 | } |
| 1421 | exit(1); |
| 1422 | } |
| 1423 | |
| 1424 | static void |
| 1425 | child_close_fds(struct ssh *ssh) |
| 1426 | { |
| 1427 | extern int auth_sock; |
| 1428 | |
| 1429 | if (auth_sock != -1) { |
| 1430 | close(auth_sock); |
| 1431 | auth_sock = -1; |
| 1432 | } |
| 1433 | |
| 1434 | if (packet_get_connection_in() == packet_get_connection_out()) |
| 1435 | close(packet_get_connection_in()); |
| 1436 | else { |
| 1437 | close(packet_get_connection_in()); |
| 1438 | close(packet_get_connection_out()); |
| 1439 | } |
| 1440 | /* |
| 1441 | * Close all descriptors related to channels. They will still remain |
| 1442 | * open in the parent. |
| 1443 | */ |
| 1444 | /* XXX better use close-on-exec? -markus */ |
| 1445 | channel_close_all(ssh); |
| 1446 | |
| 1447 | /* |
| 1448 | * Close any extra file descriptors. Note that there may still be |
| 1449 | * descriptors left by system functions. They will be closed later. |
| 1450 | */ |
| 1451 | endpwent(); |
| 1452 | |
| 1453 | /* |
| 1454 | * Close any extra open file descriptors so that we don't have them |
| 1455 | * hanging around in clients. Note that we want to do this after |
| 1456 | * initgroups, because at least on Solaris 2.3 it leaves file |
| 1457 | * descriptors open. |
| 1458 | */ |
| 1459 | closefrom(STDERR_FILENO + 1); |
| 1460 | } |
| 1461 | |
| 1462 | /* |
| 1463 | * Performs common processing for the child, such as setting up the |
| 1464 | * environment, closing extra file descriptors, setting the user and group |
| 1465 | * ids, and executing the command or shell. |
| 1466 | */ |
| 1467 | #define ARGV_MAX 10 |
| 1468 | void |
| 1469 | do_child(struct ssh *ssh, Session *s, const char *command) |
| 1470 | { |
| 1471 | extern char **environ; |
| 1472 | char **env; |
| 1473 | char *argv[ARGV_MAX]; |
| 1474 | const char *shell, *shell0; |
| 1475 | struct passwd *pw = s->pw; |
| 1476 | int r = 0; |
| 1477 | |
| 1478 | /* remove hostkey from the child's memory */ |
| 1479 | destroy_sensitive_data(); |
| 1480 | packet_clear_keys(); |
| 1481 | |
| 1482 | /* Force a password change */ |
| 1483 | if (s->authctxt->force_pwchange) { |
| 1484 | do_setusercontext(pw); |
| 1485 | child_close_fds(ssh); |
| 1486 | do_pwchange(s); |
| 1487 | exit(1); |
| 1488 | } |
| 1489 | |
| 1490 | #ifdef _UNICOS |
| 1491 | cray_setup(pw->pw_uid, pw->pw_name, command); |
| 1492 | #endif /* _UNICOS */ |
| 1493 | |
| 1494 | /* |
| 1495 | * Login(1) does this as well, and it needs uid 0 for the "-h" |
| 1496 | * switch, so we let login(1) to this for us. |
| 1497 | */ |
| 1498 | #ifdef HAVE_OSF_SIA |
| 1499 | session_setup_sia(pw, s->ttyfd == -1 ? NULL : s->tty); |
| 1500 | if (!check_quietlogin(s, command)) |
| 1501 | do_motd(); |
| 1502 | #else /* HAVE_OSF_SIA */ |
| 1503 | /* When PAM is enabled we rely on it to do the nologin check */ |
| 1504 | if (!options.use_pam) |
| 1505 | do_nologin(pw); |
| 1506 | do_setusercontext(pw); |
| 1507 | /* |
| 1508 | * PAM session modules in do_setusercontext may have |
| 1509 | * generated messages, so if this in an interactive |
| 1510 | * login then display them too. |
| 1511 | */ |
| 1512 | if (!check_quietlogin(s, command)) |
| 1513 | display_loginmsg(); |
| 1514 | #endif /* HAVE_OSF_SIA */ |
| 1515 | |
| 1516 | #ifdef USE_PAM |
| 1517 | if (options.use_pam && !is_pam_session_open()) { |
| 1518 | debug3("PAM session not opened, exiting"); |
| 1519 | display_loginmsg(); |
| 1520 | exit(254); |
| 1521 | } |
| 1522 | #endif |
| 1523 | |
| 1524 | /* |
| 1525 | * Get the shell from the password data. An empty shell field is |
| 1526 | * legal, and means /bin/sh. |
| 1527 | */ |
| 1528 | shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell; |
| 1529 | |
| 1530 | /* |
| 1531 | * Make sure $SHELL points to the shell from the password file, |
| 1532 | * even if shell is overridden from login.conf |
| 1533 | */ |
| 1534 | env = do_setup_env(ssh, s, shell); |
| 1535 | |
| 1536 | #ifdef HAVE_LOGIN_CAP |
| 1537 | shell = login_getcapstr(lc, "shell", (char *)shell, (char *)shell); |
| 1538 | #endif |
| 1539 | |
| 1540 | /* |
| 1541 | * Close the connection descriptors; note that this is the child, and |
| 1542 | * the server will still have the socket open, and it is important |
| 1543 | * that we do not shutdown it. Note that the descriptors cannot be |
| 1544 | * closed before building the environment, as we call |
| 1545 | * ssh_remote_ipaddr there. |
| 1546 | */ |
| 1547 | child_close_fds(ssh); |
| 1548 | |
| 1549 | /* |
| 1550 | * Must take new environment into use so that .ssh/rc, |
| 1551 | * /etc/ssh/sshrc and xauth are run in the proper environment. |
| 1552 | */ |
| 1553 | environ = env; |
| 1554 | |
| 1555 | #if defined(KRB5) && defined(USE_AFS) |
| 1556 | /* |
| 1557 | * At this point, we check to see if AFS is active and if we have |
| 1558 | * a valid Kerberos 5 TGT. If so, it seems like a good idea to see |
| 1559 | * if we can (and need to) extend the ticket into an AFS token. If |
| 1560 | * we don't do this, we run into potential problems if the user's |
| 1561 | * home directory is in AFS and it's not world-readable. |
| 1562 | */ |
| 1563 | |
| 1564 | if (options.kerberos_get_afs_token && k_hasafs() && |
| 1565 | (s->authctxt->krb5_ctx != NULL)) { |
| 1566 | char cell[64]; |
| 1567 | |
| 1568 | debug("Getting AFS token"); |
| 1569 | |
| 1570 | k_setpag(); |
| 1571 | |
| 1572 | if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0) |
| 1573 | krb5_afslog(s->authctxt->krb5_ctx, |
| 1574 | s->authctxt->krb5_fwd_ccache, cell, NULL); |
| 1575 | |
| 1576 | krb5_afslog_home(s->authctxt->krb5_ctx, |
| 1577 | s->authctxt->krb5_fwd_ccache, NULL, NULL, pw->pw_dir); |
| 1578 | } |
| 1579 | #endif |
| 1580 | |
| 1581 | /* Change current directory to the user's home directory. */ |
| 1582 | if (chdir(pw->pw_dir) < 0) { |
| 1583 | /* Suppress missing homedir warning for chroot case */ |
| 1584 | #ifdef HAVE_LOGIN_CAP |
| 1585 | r = login_getcapbool(lc, "requirehome", 0); |
| 1586 | #endif |
| 1587 | if (r || !in_chroot) { |
| 1588 | fprintf(stderr, "Could not chdir to home " |
| 1589 | "directory %s: %s\n", pw->pw_dir, |
| 1590 | strerror(errno)); |
| 1591 | } |
| 1592 | if (r) |
| 1593 | exit(1); |
| 1594 | } |
| 1595 | |
| 1596 | closefrom(STDERR_FILENO + 1); |
| 1597 | |
| 1598 | do_rc_files(s, shell); |
| 1599 | |
| 1600 | /* restore SIGPIPE for child */ |
| 1601 | signal(SIGPIPE, SIG_DFL); |
| 1602 | |
| 1603 | if (s->is_subsystem == SUBSYSTEM_INT_SFTP_ERROR) { |
| 1604 | printf("This service allows sftp connections only.\n"); |
| 1605 | fflush(NULL); |
| 1606 | exit(1); |
| 1607 | } else if (s->is_subsystem == SUBSYSTEM_INT_SFTP) { |
| 1608 | extern int optind, optreset; |
| 1609 | int i; |
| 1610 | char *p, *args; |
| 1611 | |
| 1612 | setproctitle("%s@%s", s->pw->pw_name, INTERNAL_SFTP_NAME); |
| 1613 | args = xstrdup(command ? command : "sftp-server"); |
| 1614 | for (i = 0, (p = strtok(args, " ")); p; (p = strtok(NULL, " "))) |
| 1615 | if (i < ARGV_MAX - 1) |
| 1616 | argv[i++] = p; |
| 1617 | argv[i] = NULL; |
| 1618 | optind = optreset = 1; |
| 1619 | __progname = argv[0]; |
| 1620 | #ifdef WITH_SELINUX |
| 1621 | ssh_selinux_change_context("sftpd_t"); |
| 1622 | #endif |
| 1623 | exit(sftp_server_main(i, argv, s->pw)); |
| 1624 | } |
| 1625 | |
| 1626 | fflush(NULL); |
| 1627 | |
| 1628 | /* Get the last component of the shell name. */ |
| 1629 | if ((shell0 = strrchr(shell, '/')) != NULL) |
| 1630 | shell0++; |
| 1631 | else |
| 1632 | shell0 = shell; |
| 1633 | |
| 1634 | /* |
| 1635 | * If we have no command, execute the shell. In this case, the shell |
| 1636 | * name to be passed in argv[0] is preceded by '-' to indicate that |
| 1637 | * this is a login shell. |
| 1638 | */ |
| 1639 | if (!command) { |
| 1640 | char argv0[256]; |
| 1641 | |
| 1642 | /* Start the shell. Set initial character to '-'. */ |
| 1643 | argv0[0] = '-'; |
| 1644 | |
| 1645 | if (strlcpy(argv0 + 1, shell0, sizeof(argv0) - 1) |
| 1646 | >= sizeof(argv0) - 1) { |
| 1647 | errno = EINVAL; |
| 1648 | perror(shell); |
| 1649 | exit(1); |
| 1650 | } |
| 1651 | |
| 1652 | /* Execute the shell. */ |
| 1653 | argv[0] = argv0; |
| 1654 | argv[1] = NULL; |
| 1655 | execve(shell, argv, env); |
| 1656 | |
| 1657 | /* Executing the shell failed. */ |
| 1658 | perror(shell); |
| 1659 | exit(1); |
| 1660 | } |
| 1661 | /* |
| 1662 | * Execute the command using the user's shell. This uses the -c |
| 1663 | * option to execute the command. |
| 1664 | */ |
| 1665 | argv[0] = (char *) shell0; |
| 1666 | argv[1] = "-c"; |
| 1667 | argv[2] = (char *) command; |
| 1668 | argv[3] = NULL; |
| 1669 | execve(shell, argv, env); |
| 1670 | perror(shell); |
| 1671 | exit(1); |
| 1672 | } |
| 1673 | |
| 1674 | void |
| 1675 | session_unused(int id) |
| 1676 | { |
| 1677 | debug3("%s: session id %d unused", __func__, id); |
| 1678 | if (id >= options.max_sessions || |
| 1679 | id >= sessions_nalloc) { |
| 1680 | fatal("%s: insane session id %d (max %d nalloc %d)", |
| 1681 | __func__, id, options.max_sessions, sessions_nalloc); |
| 1682 | } |
| 1683 | memset(&sessions[id], 0, sizeof(*sessions)); |
| 1684 | sessions[id].self = id; |
| 1685 | sessions[id].used = 0; |
| 1686 | sessions[id].chanid = -1; |
| 1687 | sessions[id].ptyfd = -1; |
| 1688 | sessions[id].ttyfd = -1; |
| 1689 | sessions[id].ptymaster = -1; |
| 1690 | sessions[id].x11_chanids = NULL; |
| 1691 | sessions[id].next_unused = sessions_first_unused; |
| 1692 | sessions_first_unused = id; |
| 1693 | } |
| 1694 | |
| 1695 | Session * |
| 1696 | session_new(void) |
| 1697 | { |
| 1698 | Session *s, *tmp; |
| 1699 | |
| 1700 | if (sessions_first_unused == -1) { |
| 1701 | if (sessions_nalloc >= options.max_sessions) |
| 1702 | return NULL; |
| 1703 | debug2("%s: allocate (allocated %d max %d)", |
| 1704 | __func__, sessions_nalloc, options.max_sessions); |
| 1705 | tmp = xrecallocarray(sessions, sessions_nalloc, |
| 1706 | sessions_nalloc + 1, sizeof(*sessions)); |
| 1707 | if (tmp == NULL) { |
| 1708 | error("%s: cannot allocate %d sessions", |
| 1709 | __func__, sessions_nalloc + 1); |
| 1710 | return NULL; |
| 1711 | } |
| 1712 | sessions = tmp; |
| 1713 | session_unused(sessions_nalloc++); |
| 1714 | } |
| 1715 | |
| 1716 | if (sessions_first_unused >= sessions_nalloc || |
| 1717 | sessions_first_unused < 0) { |
| 1718 | fatal("%s: insane first_unused %d max %d nalloc %d", |
| 1719 | __func__, sessions_first_unused, options.max_sessions, |
| 1720 | sessions_nalloc); |
| 1721 | } |
| 1722 | |
| 1723 | s = &sessions[sessions_first_unused]; |
| 1724 | if (s->used) { |
| 1725 | fatal("%s: session %d already used", |
| 1726 | __func__, sessions_first_unused); |
| 1727 | } |
| 1728 | sessions_first_unused = s->next_unused; |
| 1729 | s->used = 1; |
| 1730 | s->next_unused = -1; |
| 1731 | debug("session_new: session %d", s->self); |
| 1732 | |
| 1733 | return s; |
| 1734 | } |
| 1735 | |
| 1736 | static void |
| 1737 | session_dump(void) |
| 1738 | { |
| 1739 | int i; |
| 1740 | for (i = 0; i < sessions_nalloc; i++) { |
| 1741 | Session *s = &sessions[i]; |
| 1742 | |
| 1743 | debug("dump: used %d next_unused %d session %d %p " |
| 1744 | "channel %d pid %ld", |
| 1745 | s->used, |
| 1746 | s->next_unused, |
| 1747 | s->self, |
| 1748 | s, |
| 1749 | s->chanid, |
| 1750 | (long)s->pid); |
| 1751 | } |
| 1752 | } |
| 1753 | |
| 1754 | int |
| 1755 | session_open(Authctxt *authctxt, int chanid) |
| 1756 | { |
| 1757 | Session *s = session_new(); |
| 1758 | debug("session_open: channel %d", chanid); |
| 1759 | if (s == NULL) { |
| 1760 | error("no more sessions"); |
| 1761 | return 0; |
| 1762 | } |
| 1763 | s->authctxt = authctxt; |
| 1764 | s->pw = authctxt->pw; |
| 1765 | if (s->pw == NULL || !authctxt->valid) |
| 1766 | fatal("no user for session %d", s->self); |
| 1767 | debug("session_open: session %d: link with channel %d", s->self, chanid); |
| 1768 | s->chanid = chanid; |
| 1769 | return 1; |
| 1770 | } |
| 1771 | |
| 1772 | Session * |
| 1773 | session_by_tty(char *tty) |
| 1774 | { |
| 1775 | int i; |
| 1776 | for (i = 0; i < sessions_nalloc; i++) { |
| 1777 | Session *s = &sessions[i]; |
| 1778 | if (s->used && s->ttyfd != -1 && strcmp(s->tty, tty) == 0) { |
| 1779 | debug("session_by_tty: session %d tty %s", i, tty); |
| 1780 | return s; |
| 1781 | } |
| 1782 | } |
| 1783 | debug("session_by_tty: unknown tty %.100s", tty); |
| 1784 | session_dump(); |
| 1785 | return NULL; |
| 1786 | } |
| 1787 | |
| 1788 | static Session * |
| 1789 | session_by_channel(int id) |
| 1790 | { |
| 1791 | int i; |
| 1792 | for (i = 0; i < sessions_nalloc; i++) { |
| 1793 | Session *s = &sessions[i]; |
| 1794 | if (s->used && s->chanid == id) { |
| 1795 | debug("session_by_channel: session %d channel %d", |
| 1796 | i, id); |
| 1797 | return s; |
| 1798 | } |
| 1799 | } |
| 1800 | debug("session_by_channel: unknown channel %d", id); |
| 1801 | session_dump(); |
| 1802 | return NULL; |
| 1803 | } |
| 1804 | |
| 1805 | static Session * |
| 1806 | session_by_x11_channel(int id) |
| 1807 | { |
| 1808 | int i, j; |
| 1809 | |
| 1810 | for (i = 0; i < sessions_nalloc; i++) { |
| 1811 | Session *s = &sessions[i]; |
| 1812 | |
| 1813 | if (s->x11_chanids == NULL || !s->used) |
| 1814 | continue; |
| 1815 | for (j = 0; s->x11_chanids[j] != -1; j++) { |
| 1816 | if (s->x11_chanids[j] == id) { |
| 1817 | debug("session_by_x11_channel: session %d " |
| 1818 | "channel %d", s->self, id); |
| 1819 | return s; |
| 1820 | } |
| 1821 | } |
| 1822 | } |
| 1823 | debug("session_by_x11_channel: unknown channel %d", id); |
| 1824 | session_dump(); |
| 1825 | return NULL; |
| 1826 | } |
| 1827 | |
| 1828 | static Session * |
| 1829 | session_by_pid(pid_t pid) |
| 1830 | { |
| 1831 | int i; |
| 1832 | debug("session_by_pid: pid %ld", (long)pid); |
| 1833 | for (i = 0; i < sessions_nalloc; i++) { |
| 1834 | Session *s = &sessions[i]; |
| 1835 | if (s->used && s->pid == pid) |
| 1836 | return s; |
| 1837 | } |
| 1838 | error("session_by_pid: unknown pid %ld", (long)pid); |
| 1839 | session_dump(); |
| 1840 | return NULL; |
| 1841 | } |
| 1842 | |
| 1843 | static int |
| 1844 | session_window_change_req(struct ssh *ssh, Session *s) |
| 1845 | { |
| 1846 | s->col = packet_get_int(); |
| 1847 | s->row = packet_get_int(); |
| 1848 | s->xpixel = packet_get_int(); |
| 1849 | s->ypixel = packet_get_int(); |
| 1850 | packet_check_eom(); |
| 1851 | pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel); |
| 1852 | return 1; |
| 1853 | } |
| 1854 | |
| 1855 | static int |
| 1856 | session_pty_req(struct ssh *ssh, Session *s) |
| 1857 | { |
| 1858 | u_int len; |
| 1859 | int n_bytes; |
| 1860 | |
| 1861 | if (no_pty_flag || !options.permit_tty) { |
| 1862 | debug("Allocating a pty not permitted for this authentication."); |
| 1863 | return 0; |
| 1864 | } |
| 1865 | if (s->ttyfd != -1) { |
| 1866 | packet_disconnect("Protocol error: you already have a pty."); |
| 1867 | return 0; |
| 1868 | } |
| 1869 | |
| 1870 | s->term = packet_get_string(&len); |
| 1871 | s->col = packet_get_int(); |
| 1872 | s->row = packet_get_int(); |
| 1873 | s->xpixel = packet_get_int(); |
| 1874 | s->ypixel = packet_get_int(); |
| 1875 | |
| 1876 | if (strcmp(s->term, "") == 0) { |
| 1877 | free(s->term); |
| 1878 | s->term = NULL; |
| 1879 | } |
| 1880 | |
| 1881 | /* Allocate a pty and open it. */ |
| 1882 | debug("Allocating pty."); |
| 1883 | if (!PRIVSEP(pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, |
| 1884 | sizeof(s->tty)))) { |
| 1885 | free(s->term); |
| 1886 | s->term = NULL; |
| 1887 | s->ptyfd = -1; |
| 1888 | s->ttyfd = -1; |
| 1889 | error("session_pty_req: session %d alloc failed", s->self); |
| 1890 | return 0; |
| 1891 | } |
| 1892 | debug("session_pty_req: session %d alloc %s", s->self, s->tty); |
| 1893 | |
| 1894 | n_bytes = packet_remaining(); |
| 1895 | tty_parse_modes(s->ttyfd, &n_bytes); |
| 1896 | |
| 1897 | if (!use_privsep) |
| 1898 | pty_setowner(s->pw, s->tty); |
| 1899 | |
| 1900 | /* Set window size from the packet. */ |
| 1901 | pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel); |
| 1902 | |
| 1903 | packet_check_eom(); |
| 1904 | session_proctitle(s); |
| 1905 | return 1; |
| 1906 | } |
| 1907 | |
| 1908 | static int |
| 1909 | session_subsystem_req(struct ssh *ssh, Session *s) |
| 1910 | { |
| 1911 | struct stat st; |
| 1912 | u_int len; |
| 1913 | int success = 0; |
| 1914 | char *prog, *cmd; |
| 1915 | u_int i; |
| 1916 | |
| 1917 | s->subsys = packet_get_string(&len); |
| 1918 | packet_check_eom(); |
| 1919 | debug2("subsystem request for %.100s by user %s", s->subsys, |
| 1920 | s->pw->pw_name); |
| 1921 | |
| 1922 | for (i = 0; i < options.num_subsystems; i++) { |
| 1923 | if (strcmp(s->subsys, options.subsystem_name[i]) == 0) { |
| 1924 | prog = options.subsystem_command[i]; |
| 1925 | cmd = options.subsystem_args[i]; |
| 1926 | if (strcmp(INTERNAL_SFTP_NAME, prog) == 0) { |
| 1927 | s->is_subsystem = SUBSYSTEM_INT_SFTP; |
| 1928 | debug("subsystem: %s", prog); |
| 1929 | } else { |
| 1930 | if (stat(prog, &st) < 0) |
| 1931 | debug("subsystem: cannot stat %s: %s", |
| 1932 | prog, strerror(errno)); |
| 1933 | s->is_subsystem = SUBSYSTEM_EXT; |
| 1934 | debug("subsystem: exec() %s", cmd); |
| 1935 | } |
| 1936 | success = do_exec(ssh, s, cmd) == 0; |
| 1937 | break; |
| 1938 | } |
| 1939 | } |
| 1940 | |
| 1941 | if (!success) |
| 1942 | logit("subsystem request for %.100s by user %s failed, " |
| 1943 | "subsystem not found", s->subsys, s->pw->pw_name); |
| 1944 | |
| 1945 | return success; |
| 1946 | } |
| 1947 | |
| 1948 | static int |
| 1949 | session_x11_req(struct ssh *ssh, Session *s) |
| 1950 | { |
| 1951 | int success; |
| 1952 | |
| 1953 | if (s->auth_proto != NULL || s->auth_data != NULL) { |
| 1954 | error("session_x11_req: session %d: " |
| 1955 | "x11 forwarding already active", s->self); |
| 1956 | return 0; |
| 1957 | } |
| 1958 | s->single_connection = packet_get_char(); |
| 1959 | s->auth_proto = packet_get_string(NULL); |
| 1960 | s->auth_data = packet_get_string(NULL); |
| 1961 | s->screen = packet_get_int(); |
| 1962 | packet_check_eom(); |
| 1963 | |
| 1964 | if (xauth_valid_string(s->auth_proto) && |
| 1965 | xauth_valid_string(s->auth_data)) |
| 1966 | success = session_setup_x11fwd(ssh, s); |
| 1967 | else { |
| 1968 | success = 0; |
| 1969 | error("Invalid X11 forwarding data"); |
| 1970 | } |
| 1971 | if (!success) { |
| 1972 | free(s->auth_proto); |
| 1973 | free(s->auth_data); |
| 1974 | s->auth_proto = NULL; |
| 1975 | s->auth_data = NULL; |
| 1976 | } |
| 1977 | return success; |
| 1978 | } |
| 1979 | |
| 1980 | static int |
| 1981 | session_shell_req(struct ssh *ssh, Session *s) |
| 1982 | { |
| 1983 | packet_check_eom(); |
| 1984 | return do_exec(ssh, s, NULL) == 0; |
| 1985 | } |
| 1986 | |
| 1987 | static int |
| 1988 | session_exec_req(struct ssh *ssh, Session *s) |
| 1989 | { |
| 1990 | u_int len, success; |
| 1991 | |
| 1992 | char *command = packet_get_string(&len); |
| 1993 | packet_check_eom(); |
| 1994 | success = do_exec(ssh, s, command) == 0; |
| 1995 | free(command); |
| 1996 | return success; |
| 1997 | } |
| 1998 | |
| 1999 | static int |
| 2000 | session_break_req(struct ssh *ssh, Session *s) |
| 2001 | { |
| 2002 | |
| 2003 | packet_get_int(); /* ignored */ |
| 2004 | packet_check_eom(); |
| 2005 | |
| 2006 | if (s->ptymaster == -1 || tcsendbreak(s->ptymaster, 0) < 0) |
| 2007 | return 0; |
| 2008 | return 1; |
| 2009 | } |
| 2010 | |
| 2011 | static int |
| 2012 | session_env_req(struct ssh *ssh, Session *s) |
| 2013 | { |
| 2014 | char *name, *val; |
| 2015 | u_int name_len, val_len, i; |
| 2016 | |
| 2017 | name = packet_get_cstring(&name_len); |
| 2018 | val = packet_get_cstring(&val_len); |
| 2019 | packet_check_eom(); |
| 2020 | |
| 2021 | /* Don't set too many environment variables */ |
| 2022 | if (s->num_env > 128) { |
| 2023 | debug2("Ignoring env request %s: too many env vars", name); |
| 2024 | goto fail; |
| 2025 | } |
| 2026 | |
| 2027 | for (i = 0; i < options.num_accept_env; i++) { |
| 2028 | if (match_pattern(name, options.accept_env[i])) { |
| 2029 | debug2("Setting env %d: %s=%s", s->num_env, name, val); |
| 2030 | s->env = xrecallocarray(s->env, s->num_env, |
| 2031 | s->num_env + 1, sizeof(*s->env)); |
| 2032 | s->env[s->num_env].name = name; |
| 2033 | s->env[s->num_env].val = val; |
| 2034 | s->num_env++; |
| 2035 | return (1); |
| 2036 | } |
| 2037 | } |
| 2038 | debug2("Ignoring env request %s: disallowed name", name); |
| 2039 | |
| 2040 | fail: |
| 2041 | free(name); |
| 2042 | free(val); |
| 2043 | return (0); |
| 2044 | } |
| 2045 | |
| 2046 | static int |
| 2047 | session_auth_agent_req(struct ssh *ssh, Session *s) |
| 2048 | { |
| 2049 | static int called = 0; |
| 2050 | packet_check_eom(); |
| 2051 | if (no_agent_forwarding_flag || !options.allow_agent_forwarding) { |
| 2052 | debug("session_auth_agent_req: no_agent_forwarding_flag"); |
| 2053 | return 0; |
| 2054 | } |
| 2055 | if (called) { |
| 2056 | return 0; |
| 2057 | } else { |
| 2058 | called = 1; |
| 2059 | return auth_input_request_forwarding(ssh, s->pw); |
| 2060 | } |
| 2061 | } |
| 2062 | |
| 2063 | int |
| 2064 | session_input_channel_req(struct ssh *ssh, Channel *c, const char *rtype) |
| 2065 | { |
| 2066 | int success = 0; |
| 2067 | Session *s; |
| 2068 | |
| 2069 | if ((s = session_by_channel(c->self)) == NULL) { |
| 2070 | logit("%s: no session %d req %.100s", __func__, c->self, rtype); |
| 2071 | return 0; |
| 2072 | } |
| 2073 | debug("%s: session %d req %s", __func__, s->self, rtype); |
| 2074 | |
| 2075 | /* |
| 2076 | * a session is in LARVAL state until a shell, a command |
| 2077 | * or a subsystem is executed |
| 2078 | */ |
| 2079 | if (c->type == SSH_CHANNEL_LARVAL) { |
| 2080 | if (strcmp(rtype, "shell") == 0) { |
| 2081 | success = session_shell_req(ssh, s); |
| 2082 | } else if (strcmp(rtype, "exec") == 0) { |
| 2083 | success = session_exec_req(ssh, s); |
| 2084 | } else if (strcmp(rtype, "pty-req") == 0) { |
| 2085 | success = session_pty_req(ssh, s); |
| 2086 | } else if (strcmp(rtype, "x11-req") == 0) { |
| 2087 | success = session_x11_req(ssh, s); |
| 2088 | } else if (strcmp(rtype, "auth-agent-req@openssh.com") == 0) { |
| 2089 | success = session_auth_agent_req(ssh, s); |
| 2090 | } else if (strcmp(rtype, "subsystem") == 0) { |
| 2091 | success = session_subsystem_req(ssh, s); |
| 2092 | } else if (strcmp(rtype, "env") == 0) { |
| 2093 | success = session_env_req(ssh, s); |
| 2094 | } |
| 2095 | } |
| 2096 | if (strcmp(rtype, "window-change") == 0) { |
| 2097 | success = session_window_change_req(ssh, s); |
| 2098 | } else if (strcmp(rtype, "break") == 0) { |
| 2099 | success = session_break_req(ssh, s); |
| 2100 | } |
| 2101 | |
| 2102 | return success; |
| 2103 | } |
| 2104 | |
| 2105 | void |
| 2106 | session_set_fds(struct ssh *ssh, Session *s, |
| 2107 | int fdin, int fdout, int fderr, int ignore_fderr, int is_tty) |
| 2108 | { |
| 2109 | /* |
| 2110 | * now that have a child and a pipe to the child, |
| 2111 | * we can activate our channel and register the fd's |
| 2112 | */ |
| 2113 | if (s->chanid == -1) |
| 2114 | fatal("no channel for session %d", s->self); |
| 2115 | channel_set_fds(ssh, s->chanid, |
| 2116 | fdout, fdin, fderr, |
| 2117 | ignore_fderr ? CHAN_EXTENDED_IGNORE : CHAN_EXTENDED_READ, |
| 2118 | 1, is_tty, CHAN_SES_WINDOW_DEFAULT); |
| 2119 | } |
| 2120 | |
| 2121 | /* |
| 2122 | * Function to perform pty cleanup. Also called if we get aborted abnormally |
| 2123 | * (e.g., due to a dropped connection). |
| 2124 | */ |
| 2125 | void |
| 2126 | session_pty_cleanup2(Session *s) |
| 2127 | { |
| 2128 | if (s == NULL) { |
| 2129 | error("session_pty_cleanup: no session"); |
| 2130 | return; |
| 2131 | } |
| 2132 | if (s->ttyfd == -1) |
| 2133 | return; |
| 2134 | |
| 2135 | debug("session_pty_cleanup: session %d release %s", s->self, s->tty); |
| 2136 | |
| 2137 | /* Record that the user has logged out. */ |
| 2138 | if (s->pid != 0) |
| 2139 | record_logout(s->pid, s->tty, s->pw->pw_name); |
| 2140 | |
| 2141 | /* Release the pseudo-tty. */ |
| 2142 | if (getuid() == 0) |
| 2143 | pty_release(s->tty); |
| 2144 | |
| 2145 | /* |
| 2146 | * Close the server side of the socket pairs. We must do this after |
| 2147 | * the pty cleanup, so that another process doesn't get this pty |
| 2148 | * while we're still cleaning up. |
| 2149 | */ |
| 2150 | if (s->ptymaster != -1 && close(s->ptymaster) < 0) |
| 2151 | error("close(s->ptymaster/%d): %s", |
| 2152 | s->ptymaster, strerror(errno)); |
| 2153 | |
| 2154 | /* unlink pty from session */ |
| 2155 | s->ttyfd = -1; |
| 2156 | } |
| 2157 | |
| 2158 | void |
| 2159 | session_pty_cleanup(Session *s) |
| 2160 | { |
| 2161 | PRIVSEP(session_pty_cleanup2(s)); |
| 2162 | } |
| 2163 | |
| 2164 | static char * |
| 2165 | sig2name(int sig) |
| 2166 | { |
| 2167 | #define SSH_SIG(x) if (sig == SIG ## x) return #x |
| 2168 | SSH_SIG(ABRT); |
| 2169 | SSH_SIG(ALRM); |
| 2170 | SSH_SIG(FPE); |
| 2171 | SSH_SIG(HUP); |
| 2172 | SSH_SIG(ILL); |
| 2173 | SSH_SIG(INT); |
| 2174 | SSH_SIG(KILL); |
| 2175 | SSH_SIG(PIPE); |
| 2176 | SSH_SIG(QUIT); |
| 2177 | SSH_SIG(SEGV); |
| 2178 | SSH_SIG(TERM); |
| 2179 | SSH_SIG(USR1); |
| 2180 | SSH_SIG(USR2); |
| 2181 | #undef SSH_SIG |
| 2182 | return "SIG@openssh.com"; |
| 2183 | } |
| 2184 | |
| 2185 | static void |
| 2186 | session_close_x11(struct ssh *ssh, int id) |
| 2187 | { |
| 2188 | Channel *c; |
| 2189 | |
| 2190 | if ((c = channel_by_id(ssh, id)) == NULL) { |
| 2191 | debug("%s: x11 channel %d missing", __func__, id); |
| 2192 | } else { |
| 2193 | /* Detach X11 listener */ |
| 2194 | debug("%s: detach x11 channel %d", __func__, id); |
| 2195 | channel_cancel_cleanup(ssh, id); |
| 2196 | if (c->ostate != CHAN_OUTPUT_CLOSED) |
| 2197 | chan_mark_dead(ssh, c); |
| 2198 | } |
| 2199 | } |
| 2200 | |
| 2201 | static void |
| 2202 | session_close_single_x11(struct ssh *ssh, int id, void *arg) |
| 2203 | { |
| 2204 | Session *s; |
| 2205 | u_int i; |
| 2206 | |
| 2207 | debug3("%s: channel %d", __func__, id); |
| 2208 | channel_cancel_cleanup(ssh, id); |
| 2209 | if ((s = session_by_x11_channel(id)) == NULL) |
| 2210 | fatal("%s: no x11 channel %d", __func__, id); |
| 2211 | for (i = 0; s->x11_chanids[i] != -1; i++) { |
| 2212 | debug("%s: session %d: closing channel %d", |
| 2213 | __func__, s->self, s->x11_chanids[i]); |
| 2214 | /* |
| 2215 | * The channel "id" is already closing, but make sure we |
| 2216 | * close all of its siblings. |
| 2217 | */ |
| 2218 | if (s->x11_chanids[i] != id) |
| 2219 | session_close_x11(ssh, s->x11_chanids[i]); |
| 2220 | } |
| 2221 | free(s->x11_chanids); |
| 2222 | s->x11_chanids = NULL; |
| 2223 | free(s->display); |
| 2224 | s->display = NULL; |
| 2225 | free(s->auth_proto); |
| 2226 | s->auth_proto = NULL; |
| 2227 | free(s->auth_data); |
| 2228 | s->auth_data = NULL; |
| 2229 | free(s->auth_display); |
| 2230 | s->auth_display = NULL; |
| 2231 | } |
| 2232 | |
| 2233 | static void |
| 2234 | session_exit_message(struct ssh *ssh, Session *s, int status) |
| 2235 | { |
| 2236 | Channel *c; |
| 2237 | |
| 2238 | if ((c = channel_lookup(ssh, s->chanid)) == NULL) |
| 2239 | fatal("%s: session %d: no channel %d", |
| 2240 | __func__, s->self, s->chanid); |
| 2241 | debug("%s: session %d channel %d pid %ld", |
| 2242 | __func__, s->self, s->chanid, (long)s->pid); |
| 2243 | |
| 2244 | if (WIFEXITED(status)) { |
| 2245 | channel_request_start(ssh, s->chanid, "exit-status", 0); |
| 2246 | packet_put_int(WEXITSTATUS(status)); |
| 2247 | packet_send(); |
| 2248 | } else if (WIFSIGNALED(status)) { |
| 2249 | channel_request_start(ssh, s->chanid, "exit-signal", 0); |
| 2250 | packet_put_cstring(sig2name(WTERMSIG(status))); |
| 2251 | #ifdef WCOREDUMP |
| 2252 | packet_put_char(WCOREDUMP(status)? 1 : 0); |
| 2253 | #else /* WCOREDUMP */ |
| 2254 | packet_put_char(0); |
| 2255 | #endif /* WCOREDUMP */ |
| 2256 | packet_put_cstring(""); |
| 2257 | packet_put_cstring(""); |
| 2258 | packet_send(); |
| 2259 | } else { |
| 2260 | /* Some weird exit cause. Just exit. */ |
| 2261 | packet_disconnect("wait returned status %04x.", status); |
| 2262 | } |
| 2263 | |
| 2264 | /* disconnect channel */ |
| 2265 | debug("%s: release channel %d", __func__, s->chanid); |
| 2266 | |
| 2267 | /* |
| 2268 | * Adjust cleanup callback attachment to send close messages when |
| 2269 | * the channel gets EOF. The session will be then be closed |
| 2270 | * by session_close_by_channel when the childs close their fds. |
| 2271 | */ |
| 2272 | channel_register_cleanup(ssh, c->self, session_close_by_channel, 1); |
| 2273 | |
| 2274 | /* |
| 2275 | * emulate a write failure with 'chan_write_failed', nobody will be |
| 2276 | * interested in data we write. |
| 2277 | * Note that we must not call 'chan_read_failed', since there could |
| 2278 | * be some more data waiting in the pipe. |
| 2279 | */ |
| 2280 | if (c->ostate != CHAN_OUTPUT_CLOSED) |
| 2281 | chan_write_failed(ssh, c); |
| 2282 | } |
| 2283 | |
| 2284 | void |
| 2285 | session_close(struct ssh *ssh, Session *s) |
| 2286 | { |
| 2287 | u_int i; |
| 2288 | |
| 2289 | verbose("Close session: user %s from %.200s port %d id %d", |
| 2290 | s->pw->pw_name, |
| 2291 | ssh_remote_ipaddr(ssh), |
| 2292 | ssh_remote_port(ssh), |
| 2293 | s->self); |
| 2294 | |
| 2295 | if (s->ttyfd != -1) |
| 2296 | session_pty_cleanup(s); |
| 2297 | free(s->term); |
| 2298 | free(s->display); |
| 2299 | free(s->x11_chanids); |
| 2300 | free(s->auth_display); |
| 2301 | free(s->auth_data); |
| 2302 | free(s->auth_proto); |
| 2303 | free(s->subsys); |
| 2304 | if (s->env != NULL) { |
| 2305 | for (i = 0; i < s->num_env; i++) { |
| 2306 | free(s->env[i].name); |
| 2307 | free(s->env[i].val); |
| 2308 | } |
| 2309 | free(s->env); |
| 2310 | } |
| 2311 | session_proctitle(s); |
| 2312 | session_unused(s->self); |
| 2313 | } |
| 2314 | |
| 2315 | void |
| 2316 | session_close_by_pid(struct ssh *ssh, pid_t pid, int status) |
| 2317 | { |
| 2318 | Session *s = session_by_pid(pid); |
| 2319 | if (s == NULL) { |
| 2320 | debug("%s: no session for pid %ld", __func__, (long)pid); |
| 2321 | return; |
| 2322 | } |
| 2323 | if (s->chanid != -1) |
| 2324 | session_exit_message(ssh, s, status); |
| 2325 | if (s->ttyfd != -1) |
| 2326 | session_pty_cleanup(s); |
| 2327 | s->pid = 0; |
| 2328 | } |
| 2329 | |
| 2330 | /* |
| 2331 | * this is called when a channel dies before |
| 2332 | * the session 'child' itself dies |
| 2333 | */ |
| 2334 | void |
| 2335 | session_close_by_channel(struct ssh *ssh, int id, void *arg) |
| 2336 | { |
| 2337 | Session *s = session_by_channel(id); |
| 2338 | u_int i; |
| 2339 | |
| 2340 | if (s == NULL) { |
| 2341 | debug("%s: no session for id %d", __func__, id); |
| 2342 | return; |
| 2343 | } |
| 2344 | debug("%s: channel %d child %ld", __func__, id, (long)s->pid); |
| 2345 | if (s->pid != 0) { |
| 2346 | debug("%s: channel %d: has child", __func__, id); |
| 2347 | /* |
| 2348 | * delay detach of session, but release pty, since |
| 2349 | * the fd's to the child are already closed |
| 2350 | */ |
| 2351 | if (s->ttyfd != -1) |
| 2352 | session_pty_cleanup(s); |
| 2353 | return; |
| 2354 | } |
| 2355 | /* detach by removing callback */ |
| 2356 | channel_cancel_cleanup(ssh, s->chanid); |
| 2357 | |
| 2358 | /* Close any X11 listeners associated with this session */ |
| 2359 | if (s->x11_chanids != NULL) { |
| 2360 | for (i = 0; s->x11_chanids[i] != -1; i++) { |
| 2361 | session_close_x11(ssh, s->x11_chanids[i]); |
| 2362 | s->x11_chanids[i] = -1; |
| 2363 | } |
| 2364 | } |
| 2365 | |
| 2366 | s->chanid = -1; |
| 2367 | session_close(ssh, s); |
| 2368 | } |
| 2369 | |
| 2370 | void |
| 2371 | session_destroy_all(struct ssh *ssh, void (*closefunc)(Session *)) |
| 2372 | { |
| 2373 | int i; |
| 2374 | for (i = 0; i < sessions_nalloc; i++) { |
| 2375 | Session *s = &sessions[i]; |
| 2376 | if (s->used) { |
| 2377 | if (closefunc != NULL) |
| 2378 | closefunc(s); |
| 2379 | else |
| 2380 | session_close(ssh, s); |
| 2381 | } |
| 2382 | } |
| 2383 | } |
| 2384 | |
| 2385 | static char * |
| 2386 | session_tty_list(void) |
| 2387 | { |
| 2388 | static char buf[1024]; |
| 2389 | int i; |
| 2390 | char *cp; |
| 2391 | |
| 2392 | buf[0] = '\0'; |
| 2393 | for (i = 0; i < sessions_nalloc; i++) { |
| 2394 | Session *s = &sessions[i]; |
| 2395 | if (s->used && s->ttyfd != -1) { |
| 2396 | |
| 2397 | if (strncmp(s->tty, "/dev/", 5) != 0) { |
| 2398 | cp = strrchr(s->tty, '/'); |
| 2399 | cp = (cp == NULL) ? s->tty : cp + 1; |
| 2400 | } else |
| 2401 | cp = s->tty + 5; |
| 2402 | |
| 2403 | if (buf[0] != '\0') |
| 2404 | strlcat(buf, ",", sizeof buf); |
| 2405 | strlcat(buf, cp, sizeof buf); |
| 2406 | } |
| 2407 | } |
| 2408 | if (buf[0] == '\0') |
| 2409 | strlcpy(buf, "notty", sizeof buf); |
| 2410 | return buf; |
| 2411 | } |
| 2412 | |
| 2413 | void |
| 2414 | session_proctitle(Session *s) |
| 2415 | { |
| 2416 | if (s->pw == NULL) |
| 2417 | error("no user for session %d", s->self); |
| 2418 | else |
| 2419 | setproctitle("%s@%s", s->pw->pw_name, session_tty_list()); |
| 2420 | } |
| 2421 | |
| 2422 | int |
| 2423 | session_setup_x11fwd(struct ssh *ssh, Session *s) |
| 2424 | { |
| 2425 | struct stat st; |
| 2426 | char display[512], auth_display[512]; |
| 2427 | char hostname[NI_MAXHOST]; |
| 2428 | u_int i; |
| 2429 | |
| 2430 | if (no_x11_forwarding_flag) { |
| 2431 | packet_send_debug("X11 forwarding disabled in user configuration file."); |
| 2432 | return 0; |
| 2433 | } |
| 2434 | if (!options.x11_forwarding) { |
| 2435 | debug("X11 forwarding disabled in server configuration file."); |
| 2436 | return 0; |
| 2437 | } |
| 2438 | if (options.xauth_location == NULL || |
| 2439 | (stat(options.xauth_location, &st) == -1)) { |
| 2440 | packet_send_debug("No xauth program; cannot forward with spoofing."); |
| 2441 | return 0; |
| 2442 | } |
| 2443 | if (s->display != NULL) { |
| 2444 | debug("X11 display already set."); |
| 2445 | return 0; |
| 2446 | } |
| 2447 | if (x11_create_display_inet(ssh, options.x11_display_offset, |
| 2448 | options.x11_use_localhost, s->single_connection, |
| 2449 | &s->display_number, &s->x11_chanids) == -1) { |
| 2450 | debug("x11_create_display_inet failed."); |
| 2451 | return 0; |
| 2452 | } |
| 2453 | for (i = 0; s->x11_chanids[i] != -1; i++) { |
| 2454 | channel_register_cleanup(ssh, s->x11_chanids[i], |
| 2455 | session_close_single_x11, 0); |
| 2456 | } |
| 2457 | |
| 2458 | /* Set up a suitable value for the DISPLAY variable. */ |
| 2459 | if (gethostname(hostname, sizeof(hostname)) < 0) |
| 2460 | fatal("gethostname: %.100s", strerror(errno)); |
| 2461 | /* |
| 2462 | * auth_display must be used as the displayname when the |
| 2463 | * authorization entry is added with xauth(1). This will be |
| 2464 | * different than the DISPLAY string for localhost displays. |
| 2465 | */ |
| 2466 | if (options.x11_use_localhost) { |
| 2467 | snprintf(display, sizeof display, "localhost:%u.%u", |
| 2468 | s->display_number, s->screen); |
| 2469 | snprintf(auth_display, sizeof auth_display, "unix:%u.%u", |
| 2470 | s->display_number, s->screen); |
| 2471 | s->display = xstrdup(display); |
| 2472 | s->auth_display = xstrdup(auth_display); |
| 2473 | } else { |
| 2474 | #ifdef IPADDR_IN_DISPLAY |
| 2475 | struct hostent *he; |
| 2476 | struct in_addr my_addr; |
| 2477 | |
| 2478 | he = gethostbyname(hostname); |
| 2479 | if (he == NULL) { |
| 2480 | error("Can't get IP address for X11 DISPLAY."); |
| 2481 | packet_send_debug("Can't get IP address for X11 DISPLAY."); |
| 2482 | return 0; |
| 2483 | } |
| 2484 | memcpy(&my_addr, he->h_addr_list[0], sizeof(struct in_addr)); |
| 2485 | snprintf(display, sizeof display, "%.50s:%u.%u", inet_ntoa(my_addr), |
| 2486 | s->display_number, s->screen); |
| 2487 | #else |
| 2488 | snprintf(display, sizeof display, "%.400s:%u.%u", hostname, |
| 2489 | s->display_number, s->screen); |
| 2490 | #endif |
| 2491 | s->display = xstrdup(display); |
| 2492 | s->auth_display = xstrdup(display); |
| 2493 | } |
| 2494 | |
| 2495 | return 1; |
| 2496 | } |
| 2497 | |
| 2498 | static void |
| 2499 | do_authenticated2(struct ssh *ssh, Authctxt *authctxt) |
| 2500 | { |
| 2501 | server_loop2(ssh, authctxt); |
| 2502 | } |
| 2503 | |
| 2504 | void |
| 2505 | do_cleanup(struct ssh *ssh, Authctxt *authctxt) |
| 2506 | { |
| 2507 | static int called = 0; |
| 2508 | |
| 2509 | debug("do_cleanup"); |
| 2510 | |
| 2511 | /* no cleanup if we're in the child for login shell */ |
| 2512 | if (is_child) |
| 2513 | return; |
| 2514 | |
| 2515 | /* avoid double cleanup */ |
| 2516 | if (called) |
| 2517 | return; |
| 2518 | called = 1; |
| 2519 | |
| 2520 | if (authctxt == NULL) |
| 2521 | return; |
| 2522 | |
| 2523 | #ifdef USE_PAM |
| 2524 | if (options.use_pam) { |
| 2525 | sshpam_cleanup(); |
| 2526 | sshpam_thread_cleanup(); |
| 2527 | } |
| 2528 | #endif |
| 2529 | |
| 2530 | if (!authctxt->authenticated) |
| 2531 | return; |
| 2532 | |
| 2533 | #ifdef KRB5 |
| 2534 | if (options.kerberos_ticket_cleanup && |
| 2535 | authctxt->krb5_ctx) |
| 2536 | krb5_cleanup_proc(authctxt); |
| 2537 | #endif |
| 2538 | |
| 2539 | #ifdef GSSAPI |
| 2540 | if (options.gss_cleanup_creds) |
| 2541 | ssh_gssapi_cleanup_creds(); |
| 2542 | #endif |
| 2543 | |
| 2544 | /* remove agent socket */ |
| 2545 | auth_sock_cleanup_proc(authctxt->pw); |
| 2546 | |
| 2547 | /* remove userauth info */ |
| 2548 | if (auth_info_file != NULL) { |
| 2549 | temporarily_use_uid(authctxt->pw); |
| 2550 | unlink(auth_info_file); |
| 2551 | restore_uid(); |
| 2552 | free(auth_info_file); |
| 2553 | auth_info_file = NULL; |
| 2554 | } |
| 2555 | |
| 2556 | /* |
| 2557 | * Cleanup ptys/utmp only if privsep is disabled, |
| 2558 | * or if running in monitor. |
| 2559 | */ |
| 2560 | if (!use_privsep || mm_is_monitor()) |
| 2561 | session_destroy_all(ssh, session_pty_cleanup2); |
| 2562 | } |
| 2563 | |
| 2564 | /* Return a name for the remote host that fits inside utmp_size */ |
| 2565 | |
| 2566 | const char * |
| 2567 | session_get_remote_name_or_ip(struct ssh *ssh, u_int utmp_size, int use_dns) |
| 2568 | { |
| 2569 | const char *remote = ""; |
| 2570 | |
| 2571 | if (utmp_size > 0) |
| 2572 | remote = auth_get_canonical_hostname(ssh, use_dns); |
| 2573 | if (utmp_size == 0 || strlen(remote) > utmp_size) |
| 2574 | remote = ssh_remote_ipaddr(ssh); |
| 2575 | return remote; |
| 2576 | } |
| 2577 | |