1 /* $OpenBSD: clientloop.c,v 1.305 2017/09/19 04:24:22 djm Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * The main loop for the interactive session (client side). 7 * 8 * As far as I am concerned, the code I have written for this software 9 * can be used freely for any purpose. Any derived versions of this 10 * software must be clearly marked as such, and if the derived work is 11 * incompatible with the protocol description in the RFC file, it must be 12 * called by a name other than "ssh" or "Secure Shell". 13 * 14 * 15 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 16 * 17 * Redistribution and use in source and binary forms, with or without 18 * modification, are permitted provided that the following conditions 19 * are met: 20 * 1. Redistributions of source code must retain the above copyright 21 * notice, this list of conditions and the following disclaimer. 22 * 2. Redistributions in binary form must reproduce the above copyright 23 * notice, this list of conditions and the following disclaimer in the 24 * documentation and/or other materials provided with the distribution. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 27 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 28 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 29 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 30 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 31 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 35 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 36 * 37 * 38 * SSH2 support added by Markus Friedl. 39 * Copyright (c) 1999, 2000, 2001 Markus Friedl. All rights reserved. 40 * 41 * Redistribution and use in source and binary forms, with or without 42 * modification, are permitted provided that the following conditions 43 * are met: 44 * 1. Redistributions of source code must retain the above copyright 45 * notice, this list of conditions and the following disclaimer. 46 * 2. Redistributions in binary form must reproduce the above copyright 47 * notice, this list of conditions and the following disclaimer in the 48 * documentation and/or other materials provided with the distribution. 49 * 50 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 51 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 52 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 53 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 54 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 55 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 56 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 57 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 58 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 59 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 60 */ 61 62 #include "includes.h" 63 64 #include <sys/types.h> 65 #include <sys/ioctl.h> 66 #ifdef HAVE_SYS_STAT_H 67 # include <sys/stat.h> 68 #endif 69 #ifdef HAVE_SYS_TIME_H 70 # include <sys/time.h> 71 #endif 72 #include <sys/socket.h> 73 74 #include <ctype.h> 75 #include <errno.h> 76 #ifdef HAVE_PATHS_H 77 #include <paths.h> 78 #endif 79 #include <signal.h> 80 #include <stdarg.h> 81 #include <stdio.h> 82 #include <stdlib.h> 83 #include <string.h> 84 #include <termios.h> 85 #include <pwd.h> 86 #include <unistd.h> 87 #include <limits.h> 88 89 #include "openbsd-compat/sys-queue.h" 90 #include "xmalloc.h" 91 #include "ssh.h" 92 #include "ssh2.h" 93 #include "packet.h" 94 #include "buffer.h" 95 #include "compat.h" 96 #include "channels.h" 97 #include "dispatch.h" 98 #include "key.h" 99 #include "cipher.h" 100 #include "kex.h" 101 #include "myproposal.h" 102 #include "log.h" 103 #include "misc.h" 104 #include "readconf.h" 105 #include "clientloop.h" 106 #include "sshconnect.h" 107 #include "authfd.h" 108 #include "atomicio.h" 109 #include "sshpty.h" 110 #include "match.h" 111 #include "msg.h" 112 #include "ssherr.h" 113 #include "hostfile.h" 114 115 /* import options */ 116 extern Options options; 117 118 /* Flag indicating that stdin should be redirected from /dev/null. */ 119 extern int stdin_null_flag; 120 121 /* Flag indicating that no shell has been requested */ 122 extern int no_shell_flag; 123 124 /* Flag indicating that ssh should daemonise after authentication is complete */ 125 extern int fork_after_authentication_flag; 126 127 /* Control socket */ 128 extern int muxserver_sock; /* XXX use mux_client_cleanup() instead */ 129 130 /* 131 * Name of the host we are connecting to. This is the name given on the 132 * command line, or the HostName specified for the user-supplied name in a 133 * configuration file. 134 */ 135 extern char *host; 136 137 /* 138 * Flag to indicate that we have received a window change signal which has 139 * not yet been processed. This will cause a message indicating the new 140 * window size to be sent to the server a little later. This is volatile 141 * because this is updated in a signal handler. 142 */ 143 static volatile sig_atomic_t received_window_change_signal = 0; 144 static volatile sig_atomic_t received_signal = 0; 145 146 /* Flag indicating whether the user's terminal is in non-blocking mode. */ 147 static int in_non_blocking_mode = 0; 148 149 /* Time when backgrounded control master using ControlPersist should exit */ 150 static time_t control_persist_exit_time = 0; 151 152 /* Common data for the client loop code. */ 153 volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */ 154 static int last_was_cr; /* Last character was a newline. */ 155 static int exit_status; /* Used to store the command exit status. */ 156 static Buffer stderr_buffer; /* Used for final exit message. */ 157 static int connection_in; /* Connection to server (input). */ 158 static int connection_out; /* Connection to server (output). */ 159 static int need_rekeying; /* Set to non-zero if rekeying is requested. */ 160 static int session_closed; /* In SSH2: login session closed. */ 161 static u_int x11_refuse_time; /* If >0, refuse x11 opens after this time. */ 162 163 static void client_init_dispatch(void); 164 int session_ident = -1; 165 166 /* Track escape per proto2 channel */ 167 struct escape_filter_ctx { 168 int escape_pending; 169 int escape_char; 170 }; 171 172 /* Context for channel confirmation replies */ 173 struct channel_reply_ctx { 174 const char *request_type; 175 int id; 176 enum confirm_action action; 177 }; 178 179 /* Global request success/failure callbacks */ 180 /* XXX move to struct ssh? */ 181 struct global_confirm { 182 TAILQ_ENTRY(global_confirm) entry; 183 global_confirm_cb *cb; 184 void *ctx; 185 int ref_count; 186 }; 187 TAILQ_HEAD(global_confirms, global_confirm); 188 static struct global_confirms global_confirms = 189 TAILQ_HEAD_INITIALIZER(global_confirms); 190 191 void ssh_process_session2_setup(int, int, int, Buffer *); 192 193 /* Restores stdin to blocking mode. */ 194 195 static void 196 leave_non_blocking(void) 197 { 198 if (in_non_blocking_mode) { 199 unset_nonblock(fileno(stdin)); 200 in_non_blocking_mode = 0; 201 } 202 } 203 204 /* 205 * Signal handler for the window change signal (SIGWINCH). This just sets a 206 * flag indicating that the window has changed. 207 */ 208 /*ARGSUSED */ 209 static void 210 window_change_handler(int sig) 211 { 212 received_window_change_signal = 1; 213 signal(SIGWINCH, window_change_handler); 214 } 215 216 /* 217 * Signal handler for signals that cause the program to terminate. These 218 * signals must be trapped to restore terminal modes. 219 */ 220 /*ARGSUSED */ 221 static void 222 signal_handler(int sig) 223 { 224 received_signal = sig; 225 quit_pending = 1; 226 } 227 228 /* 229 * Returns current time in seconds from Jan 1, 1970 with the maximum 230 * available resolution. 231 */ 232 233 static double 234 get_current_time(void) 235 { 236 struct timeval tv; 237 gettimeofday(&tv, NULL); 238 return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0; 239 } 240 241 /* 242 * Sets control_persist_exit_time to the absolute time when the 243 * backgrounded control master should exit due to expiry of the 244 * ControlPersist timeout. Sets it to 0 if we are not a backgrounded 245 * control master process, or if there is no ControlPersist timeout. 246 */ 247 static void 248 set_control_persist_exit_time(struct ssh *ssh) 249 { 250 if (muxserver_sock == -1 || !options.control_persist 251 || options.control_persist_timeout == 0) { 252 /* not using a ControlPersist timeout */ 253 control_persist_exit_time = 0; 254 } else if (channel_still_open(ssh)) { 255 /* some client connections are still open */ 256 if (control_persist_exit_time > 0) 257 debug2("%s: cancel scheduled exit", __func__); 258 control_persist_exit_time = 0; 259 } else if (control_persist_exit_time <= 0) { 260 /* a client connection has recently closed */ 261 control_persist_exit_time = monotime() + 262 (time_t)options.control_persist_timeout; 263 debug2("%s: schedule exit in %d seconds", __func__, 264 options.control_persist_timeout); 265 } 266 /* else we are already counting down to the timeout */ 267 } 268 269 #define SSH_X11_VALID_DISPLAY_CHARS ":/.-_" 270 static int 271 client_x11_display_valid(const char *display) 272 { 273 size_t i, dlen; 274 275 if (display == NULL) 276 return 0; 277 278 dlen = strlen(display); 279 for (i = 0; i < dlen; i++) { 280 if (!isalnum((u_char)display[i]) && 281 strchr(SSH_X11_VALID_DISPLAY_CHARS, display[i]) == NULL) { 282 debug("Invalid character '%c' in DISPLAY", display[i]); 283 return 0; 284 } 285 } 286 return 1; 287 } 288 289 #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1" 290 #define X11_TIMEOUT_SLACK 60 291 int 292 client_x11_get_proto(struct ssh *ssh, const char *display, 293 const char *xauth_path, u_int trusted, u_int timeout, 294 char **_proto, char **_data) 295 { 296 char cmd[1024], line[512], xdisplay[512]; 297 char xauthfile[PATH_MAX], xauthdir[PATH_MAX]; 298 static char proto[512], data[512]; 299 FILE *f; 300 int got_data = 0, generated = 0, do_unlink = 0, r; 301 struct stat st; 302 u_int now, x11_timeout_real; 303 304 *_proto = proto; 305 *_data = data; 306 proto[0] = data[0] = xauthfile[0] = xauthdir[0] = '\0'; 307 308 if (!client_x11_display_valid(display)) { 309 if (display != NULL) 310 logit("DISPLAY \"%s\" invalid; disabling X11 forwarding", 311 display); 312 return -1; 313 } 314 if (xauth_path != NULL && stat(xauth_path, &st) == -1) { 315 debug("No xauth program."); 316 xauth_path = NULL; 317 } 318 319 if (xauth_path != NULL) { 320 /* 321 * Handle FamilyLocal case where $DISPLAY does 322 * not match an authorization entry. For this we 323 * just try "xauth list unix:displaynum.screennum". 324 * XXX: "localhost" match to determine FamilyLocal 325 * is not perfect. 326 */ 327 if (strncmp(display, "localhost:", 10) == 0) { 328 if ((r = snprintf(xdisplay, sizeof(xdisplay), "unix:%s", 329 display + 10)) < 0 || 330 (size_t)r >= sizeof(xdisplay)) { 331 error("%s: display name too long", __func__); 332 return -1; 333 } 334 display = xdisplay; 335 } 336 if (trusted == 0) { 337 /* 338 * Generate an untrusted X11 auth cookie. 339 * 340 * The authentication cookie should briefly outlive 341 * ssh's willingness to forward X11 connections to 342 * avoid nasty fail-open behaviour in the X server. 343 */ 344 mktemp_proto(xauthdir, sizeof(xauthdir)); 345 if (mkdtemp(xauthdir) == NULL) { 346 error("%s: mkdtemp: %s", 347 __func__, strerror(errno)); 348 return -1; 349 } 350 do_unlink = 1; 351 if ((r = snprintf(xauthfile, sizeof(xauthfile), 352 "%s/xauthfile", xauthdir)) < 0 || 353 (size_t)r >= sizeof(xauthfile)) { 354 error("%s: xauthfile path too long", __func__); 355 unlink(xauthfile); 356 rmdir(xauthdir); 357 return -1; 358 } 359 360 if (timeout >= UINT_MAX - X11_TIMEOUT_SLACK) 361 x11_timeout_real = UINT_MAX; 362 else 363 x11_timeout_real = timeout + X11_TIMEOUT_SLACK; 364 if ((r = snprintf(cmd, sizeof(cmd), 365 "%s -f %s generate %s " SSH_X11_PROTO 366 " untrusted timeout %u 2>" _PATH_DEVNULL, 367 xauth_path, xauthfile, display, 368 x11_timeout_real)) < 0 || 369 (size_t)r >= sizeof(cmd)) 370 fatal("%s: cmd too long", __func__); 371 debug2("%s: %s", __func__, cmd); 372 if (x11_refuse_time == 0) { 373 now = monotime() + 1; 374 if (UINT_MAX - timeout < now) 375 x11_refuse_time = UINT_MAX; 376 else 377 x11_refuse_time = now + timeout; 378 channel_set_x11_refuse_time(ssh, 379 x11_refuse_time); 380 } 381 if (system(cmd) == 0) 382 generated = 1; 383 } 384 385 /* 386 * When in untrusted mode, we read the cookie only if it was 387 * successfully generated as an untrusted one in the step 388 * above. 389 */ 390 if (trusted || generated) { 391 snprintf(cmd, sizeof(cmd), 392 "%s %s%s list %s 2>" _PATH_DEVNULL, 393 xauth_path, 394 generated ? "-f " : "" , 395 generated ? xauthfile : "", 396 display); 397 debug2("x11_get_proto: %s", cmd); 398 f = popen(cmd, "r"); 399 if (f && fgets(line, sizeof(line), f) && 400 sscanf(line, "%*s %511s %511s", proto, data) == 2) 401 got_data = 1; 402 if (f) 403 pclose(f); 404 } 405 } 406 407 if (do_unlink) { 408 unlink(xauthfile); 409 rmdir(xauthdir); 410 } 411 412 /* Don't fall back to fake X11 data for untrusted forwarding */ 413 if (!trusted && !got_data) { 414 error("Warning: untrusted X11 forwarding setup failed: " 415 "xauth key data not generated"); 416 return -1; 417 } 418 419 /* 420 * If we didn't get authentication data, just make up some 421 * data. The forwarding code will check the validity of the 422 * response anyway, and substitute this data. The X11 423 * server, however, will ignore this fake data and use 424 * whatever authentication mechanisms it was using otherwise 425 * for the local connection. 426 */ 427 if (!got_data) { 428 u_int8_t rnd[16]; 429 u_int i; 430 431 logit("Warning: No xauth data; " 432 "using fake authentication data for X11 forwarding."); 433 strlcpy(proto, SSH_X11_PROTO, sizeof proto); 434 arc4random_buf(rnd, sizeof(rnd)); 435 for (i = 0; i < sizeof(rnd); i++) { 436 snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", 437 rnd[i]); 438 } 439 } 440 441 return 0; 442 } 443 444 /* 445 * Checks if the client window has changed, and sends a packet about it to 446 * the server if so. The actual change is detected elsewhere (by a software 447 * interrupt on Unix); this just checks the flag and sends a message if 448 * appropriate. 449 */ 450 451 static void 452 client_check_window_change(struct ssh *ssh) 453 { 454 if (!received_window_change_signal) 455 return; 456 /** XXX race */ 457 received_window_change_signal = 0; 458 459 debug2("%s: changed", __func__); 460 461 channel_send_window_changes(ssh); 462 } 463 464 static int 465 client_global_request_reply(int type, u_int32_t seq, struct ssh *ssh) 466 { 467 struct global_confirm *gc; 468 469 if ((gc = TAILQ_FIRST(&global_confirms)) == NULL) 470 return 0; 471 if (gc->cb != NULL) 472 gc->cb(ssh, type, seq, gc->ctx); 473 if (--gc->ref_count <= 0) { 474 TAILQ_REMOVE(&global_confirms, gc, entry); 475 explicit_bzero(gc, sizeof(*gc)); 476 free(gc); 477 } 478 479 packet_set_alive_timeouts(0); 480 return 0; 481 } 482 483 static void 484 server_alive_check(void) 485 { 486 if (packet_inc_alive_timeouts() > options.server_alive_count_max) { 487 logit("Timeout, server %s not responding.", host); 488 cleanup_exit(255); 489 } 490 packet_start(SSH2_MSG_GLOBAL_REQUEST); 491 packet_put_cstring("keepalive@openssh.com"); 492 packet_put_char(1); /* boolean: want reply */ 493 packet_send(); 494 /* Insert an empty placeholder to maintain ordering */ 495 client_register_global_confirm(NULL, NULL); 496 } 497 498 /* 499 * Waits until the client can do something (some data becomes available on 500 * one of the file descriptors). 501 */ 502 static void 503 client_wait_until_can_do_something(struct ssh *ssh, 504 fd_set **readsetp, fd_set **writesetp, 505 int *maxfdp, u_int *nallocp, int rekeying) 506 { 507 struct timeval tv, *tvp; 508 int timeout_secs; 509 time_t minwait_secs = 0, server_alive_time = 0, now = monotime(); 510 int ret; 511 512 /* Add any selections by the channel mechanism. */ 513 channel_prepare_select(active_state, readsetp, writesetp, maxfdp, 514 nallocp, &minwait_secs); 515 516 /* channel_prepare_select could have closed the last channel */ 517 if (session_closed && !channel_still_open(ssh) && 518 !packet_have_data_to_write()) { 519 /* clear mask since we did not call select() */ 520 memset(*readsetp, 0, *nallocp); 521 memset(*writesetp, 0, *nallocp); 522 return; 523 } 524 525 FD_SET(connection_in, *readsetp); 526 527 /* Select server connection if have data to write to the server. */ 528 if (packet_have_data_to_write()) 529 FD_SET(connection_out, *writesetp); 530 531 /* 532 * Wait for something to happen. This will suspend the process until 533 * some selected descriptor can be read, written, or has some other 534 * event pending, or a timeout expires. 535 */ 536 537 timeout_secs = INT_MAX; /* we use INT_MAX to mean no timeout */ 538 if (options.server_alive_interval > 0) { 539 timeout_secs = options.server_alive_interval; 540 server_alive_time = now + options.server_alive_interval; 541 } 542 if (options.rekey_interval > 0 && !rekeying) 543 timeout_secs = MINIMUM(timeout_secs, packet_get_rekey_timeout()); 544 set_control_persist_exit_time(ssh); 545 if (control_persist_exit_time > 0) { 546 timeout_secs = MINIMUM(timeout_secs, 547 control_persist_exit_time - now); 548 if (timeout_secs < 0) 549 timeout_secs = 0; 550 } 551 if (minwait_secs != 0) 552 timeout_secs = MINIMUM(timeout_secs, (int)minwait_secs); 553 if (timeout_secs == INT_MAX) 554 tvp = NULL; 555 else { 556 tv.tv_sec = timeout_secs; 557 tv.tv_usec = 0; 558 tvp = &tv; 559 } 560 561 ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp); 562 if (ret < 0) { 563 char buf[100]; 564 565 /* 566 * We have to clear the select masks, because we return. 567 * We have to return, because the mainloop checks for the flags 568 * set by the signal handlers. 569 */ 570 memset(*readsetp, 0, *nallocp); 571 memset(*writesetp, 0, *nallocp); 572 573 if (errno == EINTR) 574 return; 575 /* Note: we might still have data in the buffers. */ 576 snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno)); 577 buffer_append(&stderr_buffer, buf, strlen(buf)); 578 quit_pending = 1; 579 } else if (ret == 0) { 580 /* 581 * Timeout. Could have been either keepalive or rekeying. 582 * Keepalive we check here, rekeying is checked in clientloop. 583 */ 584 if (server_alive_time != 0 && server_alive_time <= monotime()) 585 server_alive_check(); 586 } 587 588 } 589 590 static void 591 client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr) 592 { 593 /* Flush stdout and stderr buffers. */ 594 if (buffer_len(bout) > 0) 595 atomicio(vwrite, fileno(stdout), buffer_ptr(bout), 596 buffer_len(bout)); 597 if (buffer_len(berr) > 0) 598 atomicio(vwrite, fileno(stderr), buffer_ptr(berr), 599 buffer_len(berr)); 600 601 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 602 603 sshbuf_reset(bin); 604 sshbuf_reset(bout); 605 sshbuf_reset(berr); 606 607 /* Send the suspend signal to the program itself. */ 608 kill(getpid(), SIGTSTP); 609 610 /* Reset window sizes in case they have changed */ 611 received_window_change_signal = 1; 612 613 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 614 } 615 616 static void 617 client_process_net_input(fd_set *readset) 618 { 619 int len; 620 char buf[SSH_IOBUFSZ]; 621 622 /* 623 * Read input from the server, and add any such data to the buffer of 624 * the packet subsystem. 625 */ 626 if (FD_ISSET(connection_in, readset)) { 627 /* Read as much as possible. */ 628 len = read(connection_in, buf, sizeof(buf)); 629 if (len == 0) { 630 /* 631 * Received EOF. The remote host has closed the 632 * connection. 633 */ 634 snprintf(buf, sizeof buf, 635 "Connection to %.300s closed by remote host.\r\n", 636 host); 637 buffer_append(&stderr_buffer, buf, strlen(buf)); 638 quit_pending = 1; 639 return; 640 } 641 /* 642 * There is a kernel bug on Solaris that causes select to 643 * sometimes wake up even though there is no data available. 644 */ 645 if (len < 0 && 646 (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK)) 647 len = 0; 648 649 if (len < 0) { 650 /* 651 * An error has encountered. Perhaps there is a 652 * network problem. 653 */ 654 snprintf(buf, sizeof buf, 655 "Read from remote host %.300s: %.100s\r\n", 656 host, strerror(errno)); 657 buffer_append(&stderr_buffer, buf, strlen(buf)); 658 quit_pending = 1; 659 return; 660 } 661 packet_process_incoming(buf, len); 662 } 663 } 664 665 static void 666 client_status_confirm(struct ssh *ssh, int type, Channel *c, void *ctx) 667 { 668 struct channel_reply_ctx *cr = (struct channel_reply_ctx *)ctx; 669 char errmsg[256]; 670 int tochan; 671 672 /* 673 * If a TTY was explicitly requested, then a failure to allocate 674 * one is fatal. 675 */ 676 if (cr->action == CONFIRM_TTY && 677 (options.request_tty == REQUEST_TTY_FORCE || 678 options.request_tty == REQUEST_TTY_YES)) 679 cr->action = CONFIRM_CLOSE; 680 681 /* XXX supress on mux _client_ quietmode */ 682 tochan = options.log_level >= SYSLOG_LEVEL_ERROR && 683 c->ctl_chan != -1 && c->extended_usage == CHAN_EXTENDED_WRITE; 684 685 if (type == SSH2_MSG_CHANNEL_SUCCESS) { 686 debug2("%s request accepted on channel %d", 687 cr->request_type, c->self); 688 } else if (type == SSH2_MSG_CHANNEL_FAILURE) { 689 if (tochan) { 690 snprintf(errmsg, sizeof(errmsg), 691 "%s request failed\r\n", cr->request_type); 692 } else { 693 snprintf(errmsg, sizeof(errmsg), 694 "%s request failed on channel %d", 695 cr->request_type, c->self); 696 } 697 /* If error occurred on primary session channel, then exit */ 698 if (cr->action == CONFIRM_CLOSE && c->self == session_ident) 699 fatal("%s", errmsg); 700 /* 701 * If error occurred on mux client, append to 702 * their stderr. 703 */ 704 if (tochan) { 705 buffer_append(c->extended, errmsg, strlen(errmsg)); 706 } else 707 error("%s", errmsg); 708 if (cr->action == CONFIRM_TTY) { 709 /* 710 * If a TTY allocation error occurred, then arrange 711 * for the correct TTY to leave raw mode. 712 */ 713 if (c->self == session_ident) 714 leave_raw_mode(0); 715 else 716 mux_tty_alloc_failed(ssh, c); 717 } else if (cr->action == CONFIRM_CLOSE) { 718 chan_read_failed(ssh, c); 719 chan_write_failed(ssh, c); 720 } 721 } 722 free(cr); 723 } 724 725 static void 726 client_abandon_status_confirm(struct ssh *ssh, Channel *c, void *ctx) 727 { 728 free(ctx); 729 } 730 731 void 732 client_expect_confirm(struct ssh *ssh, int id, const char *request, 733 enum confirm_action action) 734 { 735 struct channel_reply_ctx *cr = xcalloc(1, sizeof(*cr)); 736 737 cr->request_type = request; 738 cr->action = action; 739 740 channel_register_status_confirm(ssh, id, client_status_confirm, 741 client_abandon_status_confirm, cr); 742 } 743 744 void 745 client_register_global_confirm(global_confirm_cb *cb, void *ctx) 746 { 747 struct global_confirm *gc, *last_gc; 748 749 /* Coalesce identical callbacks */ 750 last_gc = TAILQ_LAST(&global_confirms, global_confirms); 751 if (last_gc && last_gc->cb == cb && last_gc->ctx == ctx) { 752 if (++last_gc->ref_count >= INT_MAX) 753 fatal("%s: last_gc->ref_count = %d", 754 __func__, last_gc->ref_count); 755 return; 756 } 757 758 gc = xcalloc(1, sizeof(*gc)); 759 gc->cb = cb; 760 gc->ctx = ctx; 761 gc->ref_count = 1; 762 TAILQ_INSERT_TAIL(&global_confirms, gc, entry); 763 } 764 765 static void 766 process_cmdline(struct ssh *ssh) 767 { 768 void (*handler)(int); 769 char *s, *cmd; 770 int ok, delete = 0, local = 0, remote = 0, dynamic = 0; 771 struct Forward fwd; 772 773 memset(&fwd, 0, sizeof(fwd)); 774 775 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 776 handler = signal(SIGINT, SIG_IGN); 777 cmd = s = read_passphrase("\r\nssh> ", RP_ECHO); 778 if (s == NULL) 779 goto out; 780 while (isspace((u_char)*s)) 781 s++; 782 if (*s == '-') 783 s++; /* Skip cmdline '-', if any */ 784 if (*s == '\0') 785 goto out; 786 787 if (*s == 'h' || *s == 'H' || *s == '?') { 788 logit("Commands:"); 789 logit(" -L[bind_address:]port:host:hostport " 790 "Request local forward"); 791 logit(" -R[bind_address:]port:host:hostport " 792 "Request remote forward"); 793 logit(" -D[bind_address:]port " 794 "Request dynamic forward"); 795 logit(" -KL[bind_address:]port " 796 "Cancel local forward"); 797 logit(" -KR[bind_address:]port " 798 "Cancel remote forward"); 799 logit(" -KD[bind_address:]port " 800 "Cancel dynamic forward"); 801 if (!options.permit_local_command) 802 goto out; 803 logit(" !args " 804 "Execute local command"); 805 goto out; 806 } 807 808 if (*s == '!' && options.permit_local_command) { 809 s++; 810 ssh_local_cmd(s); 811 goto out; 812 } 813 814 if (*s == 'K') { 815 delete = 1; 816 s++; 817 } 818 if (*s == 'L') 819 local = 1; 820 else if (*s == 'R') 821 remote = 1; 822 else if (*s == 'D') 823 dynamic = 1; 824 else { 825 logit("Invalid command."); 826 goto out; 827 } 828 829 while (isspace((u_char)*++s)) 830 ; 831 832 /* XXX update list of forwards in options */ 833 if (delete) { 834 /* We pass 1 for dynamicfwd to restrict to 1 or 2 fields. */ 835 if (!parse_forward(&fwd, s, 1, 0)) { 836 logit("Bad forwarding close specification."); 837 goto out; 838 } 839 if (remote) 840 ok = channel_request_rforward_cancel(ssh, &fwd) == 0; 841 else if (dynamic) 842 ok = channel_cancel_lport_listener(ssh, &fwd, 843 0, &options.fwd_opts) > 0; 844 else 845 ok = channel_cancel_lport_listener(ssh, &fwd, 846 CHANNEL_CANCEL_PORT_STATIC, 847 &options.fwd_opts) > 0; 848 if (!ok) { 849 logit("Unknown port forwarding."); 850 goto out; 851 } 852 logit("Canceled forwarding."); 853 } else { 854 if (!parse_forward(&fwd, s, dynamic, remote)) { 855 logit("Bad forwarding specification."); 856 goto out; 857 } 858 if (local || dynamic) { 859 if (!channel_setup_local_fwd_listener(ssh, &fwd, 860 &options.fwd_opts)) { 861 logit("Port forwarding failed."); 862 goto out; 863 } 864 } else { 865 if (channel_request_remote_forwarding(ssh, &fwd) < 0) { 866 logit("Port forwarding failed."); 867 goto out; 868 } 869 } 870 logit("Forwarding port."); 871 } 872 873 out: 874 signal(SIGINT, handler); 875 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 876 free(cmd); 877 free(fwd.listen_host); 878 free(fwd.listen_path); 879 free(fwd.connect_host); 880 free(fwd.connect_path); 881 } 882 883 /* reasons to suppress output of an escape command in help output */ 884 #define SUPPRESS_NEVER 0 /* never suppress, always show */ 885 #define SUPPRESS_MUXCLIENT 1 /* don't show in mux client sessions */ 886 #define SUPPRESS_MUXMASTER 2 /* don't show in mux master sessions */ 887 #define SUPPRESS_SYSLOG 4 /* don't show when logging to syslog */ 888 struct escape_help_text { 889 const char *cmd; 890 const char *text; 891 unsigned int flags; 892 }; 893 static struct escape_help_text esc_txt[] = { 894 {".", "terminate session", SUPPRESS_MUXMASTER}, 895 {".", "terminate connection (and any multiplexed sessions)", 896 SUPPRESS_MUXCLIENT}, 897 {"B", "send a BREAK to the remote system", SUPPRESS_NEVER}, 898 {"C", "open a command line", SUPPRESS_MUXCLIENT}, 899 {"R", "request rekey", SUPPRESS_NEVER}, 900 {"V/v", "decrease/increase verbosity (LogLevel)", SUPPRESS_MUXCLIENT}, 901 {"^Z", "suspend ssh", SUPPRESS_MUXCLIENT}, 902 {"#", "list forwarded connections", SUPPRESS_NEVER}, 903 {"&", "background ssh (when waiting for connections to terminate)", 904 SUPPRESS_MUXCLIENT}, 905 {"?", "this message", SUPPRESS_NEVER}, 906 }; 907 908 static void 909 print_escape_help(Buffer *b, int escape_char, int mux_client, int using_stderr) 910 { 911 unsigned int i, suppress_flags; 912 char string[1024]; 913 914 snprintf(string, sizeof string, "%c?\r\n" 915 "Supported escape sequences:\r\n", escape_char); 916 buffer_append(b, string, strlen(string)); 917 918 suppress_flags = 919 (mux_client ? SUPPRESS_MUXCLIENT : 0) | 920 (mux_client ? 0 : SUPPRESS_MUXMASTER) | 921 (using_stderr ? 0 : SUPPRESS_SYSLOG); 922 923 for (i = 0; i < sizeof(esc_txt)/sizeof(esc_txt[0]); i++) { 924 if (esc_txt[i].flags & suppress_flags) 925 continue; 926 snprintf(string, sizeof string, " %c%-3s - %s\r\n", 927 escape_char, esc_txt[i].cmd, esc_txt[i].text); 928 buffer_append(b, string, strlen(string)); 929 } 930 931 snprintf(string, sizeof string, 932 " %c%c - send the escape character by typing it twice\r\n" 933 "(Note that escapes are only recognized immediately after " 934 "newline.)\r\n", escape_char, escape_char); 935 buffer_append(b, string, strlen(string)); 936 } 937 938 /* 939 * Process the characters one by one. 940 */ 941 static int 942 process_escapes(struct ssh *ssh, Channel *c, 943 Buffer *bin, Buffer *bout, Buffer *berr, 944 char *buf, int len) 945 { 946 char string[1024]; 947 pid_t pid; 948 int bytes = 0; 949 u_int i; 950 u_char ch; 951 char *s; 952 struct escape_filter_ctx *efc = c->filter_ctx == NULL ? 953 NULL : (struct escape_filter_ctx *)c->filter_ctx; 954 955 if (c->filter_ctx == NULL) 956 return 0; 957 958 if (len <= 0) 959 return (0); 960 961 for (i = 0; i < (u_int)len; i++) { 962 /* Get one character at a time. */ 963 ch = buf[i]; 964 965 if (efc->escape_pending) { 966 /* We have previously seen an escape character. */ 967 /* Clear the flag now. */ 968 efc->escape_pending = 0; 969 970 /* Process the escaped character. */ 971 switch (ch) { 972 case '.': 973 /* Terminate the connection. */ 974 snprintf(string, sizeof string, "%c.\r\n", 975 efc->escape_char); 976 buffer_append(berr, string, strlen(string)); 977 978 if (c && c->ctl_chan != -1) { 979 chan_read_failed(ssh, c); 980 chan_write_failed(ssh, c); 981 if (c->detach_user) { 982 c->detach_user(ssh, 983 c->self, NULL); 984 } 985 c->type = SSH_CHANNEL_ABANDONED; 986 buffer_clear(c->input); 987 chan_ibuf_empty(ssh, c); 988 return 0; 989 } else 990 quit_pending = 1; 991 return -1; 992 993 case 'Z' - 64: 994 /* XXX support this for mux clients */ 995 if (c && c->ctl_chan != -1) { 996 char b[16]; 997 noescape: 998 if (ch == 'Z' - 64) 999 snprintf(b, sizeof b, "^Z"); 1000 else 1001 snprintf(b, sizeof b, "%c", ch); 1002 snprintf(string, sizeof string, 1003 "%c%s escape not available to " 1004 "multiplexed sessions\r\n", 1005 efc->escape_char, b); 1006 buffer_append(berr, string, 1007 strlen(string)); 1008 continue; 1009 } 1010 /* Suspend the program. Inform the user */ 1011 snprintf(string, sizeof string, 1012 "%c^Z [suspend ssh]\r\n", efc->escape_char); 1013 buffer_append(berr, string, strlen(string)); 1014 1015 /* Restore terminal modes and suspend. */ 1016 client_suspend_self(bin, bout, berr); 1017 1018 /* We have been continued. */ 1019 continue; 1020 1021 case 'B': 1022 snprintf(string, sizeof string, 1023 "%cB\r\n", efc->escape_char); 1024 buffer_append(berr, string, strlen(string)); 1025 channel_request_start(ssh, c->self, "break", 0); 1026 packet_put_int(1000); 1027 packet_send(); 1028 continue; 1029 1030 case 'R': 1031 if (datafellows & SSH_BUG_NOREKEY) 1032 logit("Server does not " 1033 "support re-keying"); 1034 else 1035 need_rekeying = 1; 1036 continue; 1037 1038 case 'V': 1039 /* FALLTHROUGH */ 1040 case 'v': 1041 if (c && c->ctl_chan != -1) 1042 goto noescape; 1043 if (!log_is_on_stderr()) { 1044 snprintf(string, sizeof string, 1045 "%c%c [Logging to syslog]\r\n", 1046 efc->escape_char, ch); 1047 buffer_append(berr, string, 1048 strlen(string)); 1049 continue; 1050 } 1051 if (ch == 'V' && options.log_level > 1052 SYSLOG_LEVEL_QUIET) 1053 log_change_level(--options.log_level); 1054 if (ch == 'v' && options.log_level < 1055 SYSLOG_LEVEL_DEBUG3) 1056 log_change_level(++options.log_level); 1057 snprintf(string, sizeof string, 1058 "%c%c [LogLevel %s]\r\n", 1059 efc->escape_char, ch, 1060 log_level_name(options.log_level)); 1061 buffer_append(berr, string, strlen(string)); 1062 continue; 1063 1064 case '&': 1065 if (c && c->ctl_chan != -1) 1066 goto noescape; 1067 /* 1068 * Detach the program (continue to serve 1069 * connections, but put in background and no 1070 * more new connections). 1071 */ 1072 /* Restore tty modes. */ 1073 leave_raw_mode( 1074 options.request_tty == REQUEST_TTY_FORCE); 1075 1076 /* Stop listening for new connections. */ 1077 channel_stop_listening(ssh); 1078 1079 snprintf(string, sizeof string, 1080 "%c& [backgrounded]\n", efc->escape_char); 1081 buffer_append(berr, string, strlen(string)); 1082 1083 /* Fork into background. */ 1084 pid = fork(); 1085 if (pid < 0) { 1086 error("fork: %.100s", strerror(errno)); 1087 continue; 1088 } 1089 if (pid != 0) { /* This is the parent. */ 1090 /* The parent just exits. */ 1091 exit(0); 1092 } 1093 /* The child continues serving connections. */ 1094 buffer_append(bin, "\004", 1); 1095 /* fake EOF on stdin */ 1096 return -1; 1097 case '?': 1098 print_escape_help(berr, efc->escape_char, 1099 (c && c->ctl_chan != -1), 1100 log_is_on_stderr()); 1101 continue; 1102 1103 case '#': 1104 snprintf(string, sizeof string, "%c#\r\n", 1105 efc->escape_char); 1106 buffer_append(berr, string, strlen(string)); 1107 s = channel_open_message(ssh); 1108 buffer_append(berr, s, strlen(s)); 1109 free(s); 1110 continue; 1111 1112 case 'C': 1113 if (c && c->ctl_chan != -1) 1114 goto noescape; 1115 process_cmdline(ssh); 1116 continue; 1117 1118 default: 1119 if (ch != efc->escape_char) { 1120 buffer_put_char(bin, efc->escape_char); 1121 bytes++; 1122 } 1123 /* Escaped characters fall through here */ 1124 break; 1125 } 1126 } else { 1127 /* 1128 * The previous character was not an escape char. 1129 * Check if this is an escape. 1130 */ 1131 if (last_was_cr && ch == efc->escape_char) { 1132 /* 1133 * It is. Set the flag and continue to 1134 * next character. 1135 */ 1136 efc->escape_pending = 1; 1137 continue; 1138 } 1139 } 1140 1141 /* 1142 * Normal character. Record whether it was a newline, 1143 * and append it to the buffer. 1144 */ 1145 last_was_cr = (ch == '\r' || ch == '\n'); 1146 buffer_put_char(bin, ch); 1147 bytes++; 1148 } 1149 return bytes; 1150 } 1151 1152 /* 1153 * Get packets from the connection input buffer, and process them as long as 1154 * there are packets available. 1155 * 1156 * Any unknown packets received during the actual 1157 * session cause the session to terminate. This is 1158 * intended to make debugging easier since no 1159 * confirmations are sent. Any compatible protocol 1160 * extensions must be negotiated during the 1161 * preparatory phase. 1162 */ 1163 1164 static void 1165 client_process_buffered_input_packets(void) 1166 { 1167 ssh_dispatch_run_fatal(active_state, DISPATCH_NONBLOCK, &quit_pending); 1168 } 1169 1170 /* scan buf[] for '~' before sending data to the peer */ 1171 1172 /* Helper: allocate a new escape_filter_ctx and fill in its escape char */ 1173 void * 1174 client_new_escape_filter_ctx(int escape_char) 1175 { 1176 struct escape_filter_ctx *ret; 1177 1178 ret = xcalloc(1, sizeof(*ret)); 1179 ret->escape_pending = 0; 1180 ret->escape_char = escape_char; 1181 return (void *)ret; 1182 } 1183 1184 /* Free the escape filter context on channel free */ 1185 void 1186 client_filter_cleanup(struct ssh *ssh, int cid, void *ctx) 1187 { 1188 free(ctx); 1189 } 1190 1191 int 1192 client_simple_escape_filter(struct ssh *ssh, Channel *c, char *buf, int len) 1193 { 1194 if (c->extended_usage != CHAN_EXTENDED_WRITE) 1195 return 0; 1196 1197 return process_escapes(ssh, c, c->input, c->output, c->extended, 1198 buf, len); 1199 } 1200 1201 static void 1202 client_channel_closed(struct ssh *ssh, int id, void *arg) 1203 { 1204 channel_cancel_cleanup(ssh, id); 1205 session_closed = 1; 1206 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1207 } 1208 1209 /* 1210 * Implements the interactive session with the server. This is called after 1211 * the user has been authenticated, and a command has been started on the 1212 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character 1213 * used as an escape character for terminating or suspending the session. 1214 */ 1215 int 1216 client_loop(struct ssh *ssh, int have_pty, int escape_char_arg, 1217 int ssh2_chan_id) 1218 { 1219 fd_set *readset = NULL, *writeset = NULL; 1220 double start_time, total_time; 1221 int r, max_fd = 0, max_fd2 = 0, len; 1222 u_int64_t ibytes, obytes; 1223 u_int nalloc = 0; 1224 char buf[100]; 1225 1226 debug("Entering interactive session."); 1227 1228 if (options.control_master && 1229 !option_clear_or_none(options.control_path)) { 1230 debug("pledge: id"); 1231 if (pledge("stdio rpath wpath cpath unix inet dns recvfd proc exec id tty", 1232 NULL) == -1) 1233 fatal("%s pledge(): %s", __func__, strerror(errno)); 1234 1235 } else if (options.forward_x11 || options.permit_local_command) { 1236 debug("pledge: exec"); 1237 if (pledge("stdio rpath wpath cpath unix inet dns proc exec tty", 1238 NULL) == -1) 1239 fatal("%s pledge(): %s", __func__, strerror(errno)); 1240 1241 } else if (options.update_hostkeys) { 1242 debug("pledge: filesystem full"); 1243 if (pledge("stdio rpath wpath cpath unix inet dns proc tty", 1244 NULL) == -1) 1245 fatal("%s pledge(): %s", __func__, strerror(errno)); 1246 1247 } else if (!option_clear_or_none(options.proxy_command) || 1248 fork_after_authentication_flag) { 1249 debug("pledge: proc"); 1250 if (pledge("stdio cpath unix inet dns proc tty", NULL) == -1) 1251 fatal("%s pledge(): %s", __func__, strerror(errno)); 1252 1253 } else { 1254 debug("pledge: network"); 1255 if (pledge("stdio unix inet dns proc tty", NULL) == -1) 1256 fatal("%s pledge(): %s", __func__, strerror(errno)); 1257 } 1258 1259 start_time = get_current_time(); 1260 1261 /* Initialize variables. */ 1262 last_was_cr = 1; 1263 exit_status = -1; 1264 connection_in = packet_get_connection_in(); 1265 connection_out = packet_get_connection_out(); 1266 max_fd = MAXIMUM(connection_in, connection_out); 1267 1268 quit_pending = 0; 1269 1270 /* Initialize buffers. */ 1271 buffer_init(&stderr_buffer); 1272 1273 client_init_dispatch(); 1274 1275 /* 1276 * Set signal handlers, (e.g. to restore non-blocking mode) 1277 * but don't overwrite SIG_IGN, matches behaviour from rsh(1) 1278 */ 1279 if (signal(SIGHUP, SIG_IGN) != SIG_IGN) 1280 signal(SIGHUP, signal_handler); 1281 if (signal(SIGINT, SIG_IGN) != SIG_IGN) 1282 signal(SIGINT, signal_handler); 1283 if (signal(SIGQUIT, SIG_IGN) != SIG_IGN) 1284 signal(SIGQUIT, signal_handler); 1285 if (signal(SIGTERM, SIG_IGN) != SIG_IGN) 1286 signal(SIGTERM, signal_handler); 1287 signal(SIGWINCH, window_change_handler); 1288 1289 if (have_pty) 1290 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1291 1292 session_ident = ssh2_chan_id; 1293 if (session_ident != -1) { 1294 if (escape_char_arg != SSH_ESCAPECHAR_NONE) { 1295 channel_register_filter(ssh, session_ident, 1296 client_simple_escape_filter, NULL, 1297 client_filter_cleanup, 1298 client_new_escape_filter_ctx( 1299 escape_char_arg)); 1300 } 1301 channel_register_cleanup(ssh, session_ident, 1302 client_channel_closed, 0); 1303 } 1304 1305 /* Main loop of the client for the interactive session mode. */ 1306 while (!quit_pending) { 1307 1308 /* Process buffered packets sent by the server. */ 1309 client_process_buffered_input_packets(); 1310 1311 if (session_closed && !channel_still_open(ssh)) 1312 break; 1313 1314 if (ssh_packet_is_rekeying(ssh)) { 1315 debug("rekeying in progress"); 1316 } else if (need_rekeying) { 1317 /* manual rekey request */ 1318 debug("need rekeying"); 1319 if ((r = kex_start_rekex(ssh)) != 0) 1320 fatal("%s: kex_start_rekex: %s", __func__, 1321 ssh_err(r)); 1322 need_rekeying = 0; 1323 } else { 1324 /* 1325 * Make packets from buffered channel data, and 1326 * enqueue them for sending to the server. 1327 */ 1328 if (packet_not_very_much_data_to_write()) 1329 channel_output_poll(ssh); 1330 1331 /* 1332 * Check if the window size has changed, and buffer a 1333 * message about it to the server if so. 1334 */ 1335 client_check_window_change(ssh); 1336 1337 if (quit_pending) 1338 break; 1339 } 1340 /* 1341 * Wait until we have something to do (something becomes 1342 * available on one of the descriptors). 1343 */ 1344 max_fd2 = max_fd; 1345 client_wait_until_can_do_something(ssh, &readset, &writeset, 1346 &max_fd2, &nalloc, ssh_packet_is_rekeying(ssh)); 1347 1348 if (quit_pending) 1349 break; 1350 1351 /* Do channel operations unless rekeying in progress. */ 1352 if (!ssh_packet_is_rekeying(ssh)) 1353 channel_after_select(ssh, readset, writeset); 1354 1355 /* Buffer input from the connection. */ 1356 client_process_net_input(readset); 1357 1358 if (quit_pending) 1359 break; 1360 1361 /* 1362 * Send as much buffered packet data as possible to the 1363 * sender. 1364 */ 1365 if (FD_ISSET(connection_out, writeset)) 1366 packet_write_poll(); 1367 1368 /* 1369 * If we are a backgrounded control master, and the 1370 * timeout has expired without any active client 1371 * connections, then quit. 1372 */ 1373 if (control_persist_exit_time > 0) { 1374 if (monotime() >= control_persist_exit_time) { 1375 debug("ControlPersist timeout expired"); 1376 break; 1377 } 1378 } 1379 } 1380 free(readset); 1381 free(writeset); 1382 1383 /* Terminate the session. */ 1384 1385 /* Stop watching for window change. */ 1386 signal(SIGWINCH, SIG_DFL); 1387 1388 packet_start(SSH2_MSG_DISCONNECT); 1389 packet_put_int(SSH2_DISCONNECT_BY_APPLICATION); 1390 packet_put_cstring("disconnected by user"); 1391 packet_put_cstring(""); /* language tag */ 1392 packet_send(); 1393 packet_write_wait(); 1394 1395 channel_free_all(ssh); 1396 1397 if (have_pty) 1398 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1399 1400 /* restore blocking io */ 1401 if (!isatty(fileno(stdin))) 1402 unset_nonblock(fileno(stdin)); 1403 if (!isatty(fileno(stdout))) 1404 unset_nonblock(fileno(stdout)); 1405 if (!isatty(fileno(stderr))) 1406 unset_nonblock(fileno(stderr)); 1407 1408 /* 1409 * If there was no shell or command requested, there will be no remote 1410 * exit status to be returned. In that case, clear error code if the 1411 * connection was deliberately terminated at this end. 1412 */ 1413 if (no_shell_flag && received_signal == SIGTERM) { 1414 received_signal = 0; 1415 exit_status = 0; 1416 } 1417 1418 if (received_signal) { 1419 verbose("Killed by signal %d.", (int) received_signal); 1420 cleanup_exit(0); 1421 } 1422 1423 /* 1424 * In interactive mode (with pseudo tty) display a message indicating 1425 * that the connection has been closed. 1426 */ 1427 if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) { 1428 snprintf(buf, sizeof buf, 1429 "Connection to %.64s closed.\r\n", host); 1430 buffer_append(&stderr_buffer, buf, strlen(buf)); 1431 } 1432 1433 /* Output any buffered data for stderr. */ 1434 if (buffer_len(&stderr_buffer) > 0) { 1435 len = atomicio(vwrite, fileno(stderr), 1436 buffer_ptr(&stderr_buffer), buffer_len(&stderr_buffer)); 1437 if (len < 0 || (u_int)len != buffer_len(&stderr_buffer)) 1438 error("Write failed flushing stderr buffer."); 1439 else 1440 buffer_consume(&stderr_buffer, len); 1441 } 1442 1443 /* Clear and free any buffers. */ 1444 explicit_bzero(buf, sizeof(buf)); 1445 buffer_free(&stderr_buffer); 1446 1447 /* Report bytes transferred, and transfer rates. */ 1448 total_time = get_current_time() - start_time; 1449 packet_get_bytes(&ibytes, &obytes); 1450 verbose("Transferred: sent %llu, received %llu bytes, in %.1f seconds", 1451 (unsigned long long)obytes, (unsigned long long)ibytes, total_time); 1452 if (total_time > 0) 1453 verbose("Bytes per second: sent %.1f, received %.1f", 1454 obytes / total_time, ibytes / total_time); 1455 /* Return the exit status of the program. */ 1456 debug("Exit status %d", exit_status); 1457 return exit_status; 1458 } 1459 1460 /*********/ 1461 1462 static Channel * 1463 client_request_forwarded_tcpip(struct ssh *ssh, const char *request_type, 1464 int rchan, u_int rwindow, u_int rmaxpack) 1465 { 1466 Channel *c = NULL; 1467 struct sshbuf *b = NULL; 1468 char *listen_address, *originator_address; 1469 u_short listen_port, originator_port; 1470 int r; 1471 1472 /* Get rest of the packet */ 1473 listen_address = packet_get_string(NULL); 1474 listen_port = packet_get_int(); 1475 originator_address = packet_get_string(NULL); 1476 originator_port = packet_get_int(); 1477 packet_check_eom(); 1478 1479 debug("%s: listen %s port %d, originator %s port %d", __func__, 1480 listen_address, listen_port, originator_address, originator_port); 1481 1482 c = channel_connect_by_listen_address(ssh, listen_address, listen_port, 1483 "forwarded-tcpip", originator_address); 1484 1485 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) { 1486 if ((b = sshbuf_new()) == NULL) { 1487 error("%s: alloc reply", __func__); 1488 goto out; 1489 } 1490 /* reconstruct and send to muxclient */ 1491 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 1492 (r = sshbuf_put_u8(b, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1493 (r = sshbuf_put_cstring(b, request_type)) != 0 || 1494 (r = sshbuf_put_u32(b, rchan)) != 0 || 1495 (r = sshbuf_put_u32(b, rwindow)) != 0 || 1496 (r = sshbuf_put_u32(b, rmaxpack)) != 0 || 1497 (r = sshbuf_put_cstring(b, listen_address)) != 0 || 1498 (r = sshbuf_put_u32(b, listen_port)) != 0 || 1499 (r = sshbuf_put_cstring(b, originator_address)) != 0 || 1500 (r = sshbuf_put_u32(b, originator_port)) != 0 || 1501 (r = sshbuf_put_stringb(c->output, b)) != 0) { 1502 error("%s: compose for muxclient %s", __func__, 1503 ssh_err(r)); 1504 goto out; 1505 } 1506 } 1507 1508 out: 1509 sshbuf_free(b); 1510 free(originator_address); 1511 free(listen_address); 1512 return c; 1513 } 1514 1515 static Channel * 1516 client_request_forwarded_streamlocal(struct ssh *ssh, 1517 const char *request_type, int rchan) 1518 { 1519 Channel *c = NULL; 1520 char *listen_path; 1521 1522 /* Get the remote path. */ 1523 listen_path = packet_get_string(NULL); 1524 /* XXX: Skip reserved field for now. */ 1525 if (packet_get_string_ptr(NULL) == NULL) 1526 fatal("%s: packet_get_string_ptr failed", __func__); 1527 packet_check_eom(); 1528 1529 debug("%s: %s", __func__, listen_path); 1530 1531 c = channel_connect_by_listen_path(ssh, listen_path, 1532 "forwarded-streamlocal@openssh.com", "forwarded-streamlocal"); 1533 free(listen_path); 1534 return c; 1535 } 1536 1537 static Channel * 1538 client_request_x11(struct ssh *ssh, const char *request_type, int rchan) 1539 { 1540 Channel *c = NULL; 1541 char *originator; 1542 u_short originator_port; 1543 int sock; 1544 1545 if (!options.forward_x11) { 1546 error("Warning: ssh server tried X11 forwarding."); 1547 error("Warning: this is probably a break-in attempt by a " 1548 "malicious server."); 1549 return NULL; 1550 } 1551 if (x11_refuse_time != 0 && (u_int)monotime() >= x11_refuse_time) { 1552 verbose("Rejected X11 connection after ForwardX11Timeout " 1553 "expired"); 1554 return NULL; 1555 } 1556 originator = packet_get_string(NULL); 1557 if (datafellows & SSH_BUG_X11FWD) { 1558 debug2("buggy server: x11 request w/o originator_port"); 1559 originator_port = 0; 1560 } else { 1561 originator_port = packet_get_int(); 1562 } 1563 packet_check_eom(); 1564 /* XXX check permission */ 1565 debug("client_request_x11: request from %s %d", originator, 1566 originator_port); 1567 free(originator); 1568 sock = x11_connect_display(ssh); 1569 if (sock < 0) 1570 return NULL; 1571 c = channel_new(ssh, "x11", 1572 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1573 CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); 1574 c->force_drain = 1; 1575 return c; 1576 } 1577 1578 static Channel * 1579 client_request_agent(struct ssh *ssh, const char *request_type, int rchan) 1580 { 1581 Channel *c = NULL; 1582 int r, sock; 1583 1584 if (!options.forward_agent) { 1585 error("Warning: ssh server tried agent forwarding."); 1586 error("Warning: this is probably a break-in attempt by a " 1587 "malicious server."); 1588 return NULL; 1589 } 1590 if ((r = ssh_get_authentication_socket(&sock)) != 0) { 1591 if (r != SSH_ERR_AGENT_NOT_PRESENT) 1592 debug("%s: ssh_get_authentication_socket: %s", 1593 __func__, ssh_err(r)); 1594 return NULL; 1595 } 1596 c = channel_new(ssh, "authentication agent connection", 1597 SSH_CHANNEL_OPEN, sock, sock, -1, 1598 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, 1599 "authentication agent connection", 1); 1600 c->force_drain = 1; 1601 return c; 1602 } 1603 1604 int 1605 client_request_tun_fwd(struct ssh *ssh, int tun_mode, 1606 int local_tun, int remote_tun) 1607 { 1608 Channel *c; 1609 int fd; 1610 1611 if (tun_mode == SSH_TUNMODE_NO) 1612 return 0; 1613 1614 debug("Requesting tun unit %d in mode %d", local_tun, tun_mode); 1615 1616 /* Open local tunnel device */ 1617 if ((fd = tun_open(local_tun, tun_mode)) == -1) { 1618 error("Tunnel device open failed."); 1619 return -1; 1620 } 1621 1622 c = channel_new(ssh, "tun", SSH_CHANNEL_OPENING, fd, fd, -1, 1623 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1); 1624 c->datagram = 1; 1625 1626 #if defined(SSH_TUN_FILTER) 1627 if (options.tun_open == SSH_TUNMODE_POINTOPOINT) 1628 channel_register_filter(ssh, c->self, sys_tun_infilter, 1629 sys_tun_outfilter, NULL, NULL); 1630 #endif 1631 1632 packet_start(SSH2_MSG_CHANNEL_OPEN); 1633 packet_put_cstring("tun@openssh.com"); 1634 packet_put_int(c->self); 1635 packet_put_int(c->local_window_max); 1636 packet_put_int(c->local_maxpacket); 1637 packet_put_int(tun_mode); 1638 packet_put_int(remote_tun); 1639 packet_send(); 1640 1641 return 0; 1642 } 1643 1644 /* XXXX move to generic input handler */ 1645 static int 1646 client_input_channel_open(int type, u_int32_t seq, struct ssh *ssh) 1647 { 1648 Channel *c = NULL; 1649 char *ctype; 1650 int rchan; 1651 u_int rmaxpack, rwindow, len; 1652 1653 ctype = packet_get_string(&len); 1654 rchan = packet_get_int(); 1655 rwindow = packet_get_int(); 1656 rmaxpack = packet_get_int(); 1657 1658 debug("client_input_channel_open: ctype %s rchan %d win %d max %d", 1659 ctype, rchan, rwindow, rmaxpack); 1660 1661 if (strcmp(ctype, "forwarded-tcpip") == 0) { 1662 c = client_request_forwarded_tcpip(ssh, ctype, rchan, rwindow, 1663 rmaxpack); 1664 } else if (strcmp(ctype, "forwarded-streamlocal@openssh.com") == 0) { 1665 c = client_request_forwarded_streamlocal(ssh, ctype, rchan); 1666 } else if (strcmp(ctype, "x11") == 0) { 1667 c = client_request_x11(ssh, ctype, rchan); 1668 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) { 1669 c = client_request_agent(ssh, ctype, rchan); 1670 } 1671 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) { 1672 debug3("proxied to downstream: %s", ctype); 1673 } else if (c != NULL) { 1674 debug("confirm %s", ctype); 1675 c->remote_id = rchan; 1676 c->have_remote_id = 1; 1677 c->remote_window = rwindow; 1678 c->remote_maxpacket = rmaxpack; 1679 if (c->type != SSH_CHANNEL_CONNECTING) { 1680 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); 1681 packet_put_int(c->remote_id); 1682 packet_put_int(c->self); 1683 packet_put_int(c->local_window); 1684 packet_put_int(c->local_maxpacket); 1685 packet_send(); 1686 } 1687 } else { 1688 debug("failure %s", ctype); 1689 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); 1690 packet_put_int(rchan); 1691 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED); 1692 if (!(datafellows & SSH_BUG_OPENFAILURE)) { 1693 packet_put_cstring("open failed"); 1694 packet_put_cstring(""); 1695 } 1696 packet_send(); 1697 } 1698 free(ctype); 1699 return 0; 1700 } 1701 1702 static int 1703 client_input_channel_req(int type, u_int32_t seq, struct ssh *ssh) 1704 { 1705 Channel *c = NULL; 1706 int exitval, id, reply, success = 0; 1707 char *rtype; 1708 1709 id = packet_get_int(); 1710 c = channel_lookup(ssh, id); 1711 if (channel_proxy_upstream(c, type, seq, ssh)) 1712 return 0; 1713 rtype = packet_get_string(NULL); 1714 reply = packet_get_char(); 1715 1716 debug("client_input_channel_req: channel %d rtype %s reply %d", 1717 id, rtype, reply); 1718 1719 if (id == -1) { 1720 error("client_input_channel_req: request for channel -1"); 1721 } else if (c == NULL) { 1722 error("client_input_channel_req: channel %d: " 1723 "unknown channel", id); 1724 } else if (strcmp(rtype, "eow@openssh.com") == 0) { 1725 packet_check_eom(); 1726 chan_rcvd_eow(ssh, c); 1727 } else if (strcmp(rtype, "exit-status") == 0) { 1728 exitval = packet_get_int(); 1729 if (c->ctl_chan != -1) { 1730 mux_exit_message(ssh, c, exitval); 1731 success = 1; 1732 } else if (id == session_ident) { 1733 /* Record exit value of local session */ 1734 success = 1; 1735 exit_status = exitval; 1736 } else { 1737 /* Probably for a mux channel that has already closed */ 1738 debug("%s: no sink for exit-status on channel %d", 1739 __func__, id); 1740 } 1741 packet_check_eom(); 1742 } 1743 if (reply && c != NULL && !(c->flags & CHAN_CLOSE_SENT)) { 1744 if (!c->have_remote_id) 1745 fatal("%s: channel %d: no remote_id", 1746 __func__, c->self); 1747 packet_start(success ? 1748 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE); 1749 packet_put_int(c->remote_id); 1750 packet_send(); 1751 } 1752 free(rtype); 1753 return 0; 1754 } 1755 1756 struct hostkeys_update_ctx { 1757 /* The hostname and (optionally) IP address string for the server */ 1758 char *host_str, *ip_str; 1759 1760 /* 1761 * Keys received from the server and a flag for each indicating 1762 * whether they already exist in known_hosts. 1763 * keys_seen is filled in by hostkeys_find() and later (for new 1764 * keys) by client_global_hostkeys_private_confirm(). 1765 */ 1766 struct sshkey **keys; 1767 int *keys_seen; 1768 size_t nkeys, nnew; 1769 1770 /* 1771 * Keys that are in known_hosts, but were not present in the update 1772 * from the server (i.e. scheduled to be deleted). 1773 * Filled in by hostkeys_find(). 1774 */ 1775 struct sshkey **old_keys; 1776 size_t nold; 1777 }; 1778 1779 static void 1780 hostkeys_update_ctx_free(struct hostkeys_update_ctx *ctx) 1781 { 1782 size_t i; 1783 1784 if (ctx == NULL) 1785 return; 1786 for (i = 0; i < ctx->nkeys; i++) 1787 sshkey_free(ctx->keys[i]); 1788 free(ctx->keys); 1789 free(ctx->keys_seen); 1790 for (i = 0; i < ctx->nold; i++) 1791 sshkey_free(ctx->old_keys[i]); 1792 free(ctx->old_keys); 1793 free(ctx->host_str); 1794 free(ctx->ip_str); 1795 free(ctx); 1796 } 1797 1798 static int 1799 hostkeys_find(struct hostkey_foreach_line *l, void *_ctx) 1800 { 1801 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 1802 size_t i; 1803 struct sshkey **tmp; 1804 1805 if (l->status != HKF_STATUS_MATCHED || l->key == NULL) 1806 return 0; 1807 1808 /* Mark off keys we've already seen for this host */ 1809 for (i = 0; i < ctx->nkeys; i++) { 1810 if (sshkey_equal(l->key, ctx->keys[i])) { 1811 debug3("%s: found %s key at %s:%ld", __func__, 1812 sshkey_ssh_name(ctx->keys[i]), l->path, l->linenum); 1813 ctx->keys_seen[i] = 1; 1814 return 0; 1815 } 1816 } 1817 /* This line contained a key that not offered by the server */ 1818 debug3("%s: deprecated %s key at %s:%ld", __func__, 1819 sshkey_ssh_name(l->key), l->path, l->linenum); 1820 if ((tmp = recallocarray(ctx->old_keys, ctx->nold, ctx->nold + 1, 1821 sizeof(*ctx->old_keys))) == NULL) 1822 fatal("%s: recallocarray failed nold = %zu", 1823 __func__, ctx->nold); 1824 ctx->old_keys = tmp; 1825 ctx->old_keys[ctx->nold++] = l->key; 1826 l->key = NULL; 1827 1828 return 0; 1829 } 1830 1831 static void 1832 update_known_hosts(struct hostkeys_update_ctx *ctx) 1833 { 1834 int r, was_raw = 0; 1835 int loglevel = options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK ? 1836 SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_VERBOSE; 1837 char *fp, *response; 1838 size_t i; 1839 1840 for (i = 0; i < ctx->nkeys; i++) { 1841 if (ctx->keys_seen[i] != 2) 1842 continue; 1843 if ((fp = sshkey_fingerprint(ctx->keys[i], 1844 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 1845 fatal("%s: sshkey_fingerprint failed", __func__); 1846 do_log2(loglevel, "Learned new hostkey: %s %s", 1847 sshkey_type(ctx->keys[i]), fp); 1848 free(fp); 1849 } 1850 for (i = 0; i < ctx->nold; i++) { 1851 if ((fp = sshkey_fingerprint(ctx->old_keys[i], 1852 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 1853 fatal("%s: sshkey_fingerprint failed", __func__); 1854 do_log2(loglevel, "Deprecating obsolete hostkey: %s %s", 1855 sshkey_type(ctx->old_keys[i]), fp); 1856 free(fp); 1857 } 1858 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) { 1859 if (get_saved_tio() != NULL) { 1860 leave_raw_mode(1); 1861 was_raw = 1; 1862 } 1863 response = NULL; 1864 for (i = 0; !quit_pending && i < 3; i++) { 1865 free(response); 1866 response = read_passphrase("Accept updated hostkeys? " 1867 "(yes/no): ", RP_ECHO); 1868 if (strcasecmp(response, "yes") == 0) 1869 break; 1870 else if (quit_pending || response == NULL || 1871 strcasecmp(response, "no") == 0) { 1872 options.update_hostkeys = 0; 1873 break; 1874 } else { 1875 do_log2(loglevel, "Please enter " 1876 "\"yes\" or \"no\""); 1877 } 1878 } 1879 if (quit_pending || i >= 3 || response == NULL) 1880 options.update_hostkeys = 0; 1881 free(response); 1882 if (was_raw) 1883 enter_raw_mode(1); 1884 } 1885 1886 /* 1887 * Now that all the keys are verified, we can go ahead and replace 1888 * them in known_hosts (assuming SSH_UPDATE_HOSTKEYS_ASK didn't 1889 * cancel the operation). 1890 */ 1891 if (options.update_hostkeys != 0 && 1892 (r = hostfile_replace_entries(options.user_hostfiles[0], 1893 ctx->host_str, ctx->ip_str, ctx->keys, ctx->nkeys, 1894 options.hash_known_hosts, 0, 1895 options.fingerprint_hash)) != 0) 1896 error("%s: hostfile_replace_entries failed: %s", 1897 __func__, ssh_err(r)); 1898 } 1899 1900 static void 1901 client_global_hostkeys_private_confirm(struct ssh *ssh, int type, 1902 u_int32_t seq, void *_ctx) 1903 { 1904 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 1905 size_t i, ndone; 1906 struct sshbuf *signdata; 1907 int r; 1908 const u_char *sig; 1909 size_t siglen; 1910 1911 if (ctx->nnew == 0) 1912 fatal("%s: ctx->nnew == 0", __func__); /* sanity */ 1913 if (type != SSH2_MSG_REQUEST_SUCCESS) { 1914 error("Server failed to confirm ownership of " 1915 "private host keys"); 1916 hostkeys_update_ctx_free(ctx); 1917 return; 1918 } 1919 if ((signdata = sshbuf_new()) == NULL) 1920 fatal("%s: sshbuf_new failed", __func__); 1921 /* Don't want to accidentally accept an unbound signature */ 1922 if (ssh->kex->session_id_len == 0) 1923 fatal("%s: ssh->kex->session_id_len == 0", __func__); 1924 /* 1925 * Expect a signature for each of the ctx->nnew private keys we 1926 * haven't seen before. They will be in the same order as the 1927 * ctx->keys where the corresponding ctx->keys_seen[i] == 0. 1928 */ 1929 for (ndone = i = 0; i < ctx->nkeys; i++) { 1930 if (ctx->keys_seen[i]) 1931 continue; 1932 /* Prepare data to be signed: session ID, unique string, key */ 1933 sshbuf_reset(signdata); 1934 if ( (r = sshbuf_put_cstring(signdata, 1935 "hostkeys-prove-00@openssh.com")) != 0 || 1936 (r = sshbuf_put_string(signdata, ssh->kex->session_id, 1937 ssh->kex->session_id_len)) != 0 || 1938 (r = sshkey_puts(ctx->keys[i], signdata)) != 0) 1939 fatal("%s: failed to prepare signature: %s", 1940 __func__, ssh_err(r)); 1941 /* Extract and verify signature */ 1942 if ((r = sshpkt_get_string_direct(ssh, &sig, &siglen)) != 0) { 1943 error("%s: couldn't parse message: %s", 1944 __func__, ssh_err(r)); 1945 goto out; 1946 } 1947 if ((r = sshkey_verify(ctx->keys[i], sig, siglen, 1948 sshbuf_ptr(signdata), sshbuf_len(signdata), 0)) != 0) { 1949 error("%s: server gave bad signature for %s key %zu", 1950 __func__, sshkey_type(ctx->keys[i]), i); 1951 goto out; 1952 } 1953 /* Key is good. Mark it as 'seen' */ 1954 ctx->keys_seen[i] = 2; 1955 ndone++; 1956 } 1957 if (ndone != ctx->nnew) 1958 fatal("%s: ndone != ctx->nnew (%zu / %zu)", __func__, 1959 ndone, ctx->nnew); /* Shouldn't happen */ 1960 ssh_packet_check_eom(ssh); 1961 1962 /* Make the edits to known_hosts */ 1963 update_known_hosts(ctx); 1964 out: 1965 hostkeys_update_ctx_free(ctx); 1966 } 1967 1968 /* 1969 * Returns non-zero if the key is accepted by HostkeyAlgorithms. 1970 * Made slightly less trivial by the multiple RSA signature algorithm names. 1971 */ 1972 static int 1973 key_accepted_by_hostkeyalgs(const struct sshkey *key) 1974 { 1975 const char *ktype = sshkey_ssh_name(key); 1976 const char *hostkeyalgs = options.hostkeyalgorithms != NULL ? 1977 options.hostkeyalgorithms : KEX_DEFAULT_PK_ALG; 1978 1979 if (key == NULL || key->type == KEY_UNSPEC) 1980 return 0; 1981 if (key->type == KEY_RSA && 1982 (match_pattern_list("rsa-sha2-256", hostkeyalgs, 0) == 1 || 1983 match_pattern_list("rsa-sha2-512", hostkeyalgs, 0) == 1)) 1984 return 1; 1985 return match_pattern_list(ktype, hostkeyalgs, 0) == 1; 1986 } 1987 1988 /* 1989 * Handle hostkeys-00@openssh.com global request to inform the client of all 1990 * the server's hostkeys. The keys are checked against the user's 1991 * HostkeyAlgorithms preference before they are accepted. 1992 */ 1993 static int 1994 client_input_hostkeys(void) 1995 { 1996 struct ssh *ssh = active_state; /* XXX */ 1997 const u_char *blob = NULL; 1998 size_t i, len = 0; 1999 struct sshbuf *buf = NULL; 2000 struct sshkey *key = NULL, **tmp; 2001 int r; 2002 char *fp; 2003 static int hostkeys_seen = 0; /* XXX use struct ssh */ 2004 extern struct sockaddr_storage hostaddr; /* XXX from ssh.c */ 2005 struct hostkeys_update_ctx *ctx = NULL; 2006 2007 if (hostkeys_seen) 2008 fatal("%s: server already sent hostkeys", __func__); 2009 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK && 2010 options.batch_mode) 2011 return 1; /* won't ask in batchmode, so don't even try */ 2012 if (!options.update_hostkeys || options.num_user_hostfiles <= 0) 2013 return 1; 2014 2015 ctx = xcalloc(1, sizeof(*ctx)); 2016 while (ssh_packet_remaining(ssh) > 0) { 2017 sshkey_free(key); 2018 key = NULL; 2019 if ((r = sshpkt_get_string_direct(ssh, &blob, &len)) != 0) { 2020 error("%s: couldn't parse message: %s", 2021 __func__, ssh_err(r)); 2022 goto out; 2023 } 2024 if ((r = sshkey_from_blob(blob, len, &key)) != 0) { 2025 error("%s: parse key: %s", __func__, ssh_err(r)); 2026 goto out; 2027 } 2028 fp = sshkey_fingerprint(key, options.fingerprint_hash, 2029 SSH_FP_DEFAULT); 2030 debug3("%s: received %s key %s", __func__, 2031 sshkey_type(key), fp); 2032 free(fp); 2033 2034 if (!key_accepted_by_hostkeyalgs(key)) { 2035 debug3("%s: %s key not permitted by HostkeyAlgorithms", 2036 __func__, sshkey_ssh_name(key)); 2037 continue; 2038 } 2039 /* Skip certs */ 2040 if (sshkey_is_cert(key)) { 2041 debug3("%s: %s key is a certificate; skipping", 2042 __func__, sshkey_ssh_name(key)); 2043 continue; 2044 } 2045 /* Ensure keys are unique */ 2046 for (i = 0; i < ctx->nkeys; i++) { 2047 if (sshkey_equal(key, ctx->keys[i])) { 2048 error("%s: received duplicated %s host key", 2049 __func__, sshkey_ssh_name(key)); 2050 goto out; 2051 } 2052 } 2053 /* Key is good, record it */ 2054 if ((tmp = recallocarray(ctx->keys, ctx->nkeys, ctx->nkeys + 1, 2055 sizeof(*ctx->keys))) == NULL) 2056 fatal("%s: recallocarray failed nkeys = %zu", 2057 __func__, ctx->nkeys); 2058 ctx->keys = tmp; 2059 ctx->keys[ctx->nkeys++] = key; 2060 key = NULL; 2061 } 2062 2063 if (ctx->nkeys == 0) { 2064 debug("%s: server sent no hostkeys", __func__); 2065 goto out; 2066 } 2067 2068 if ((ctx->keys_seen = calloc(ctx->nkeys, 2069 sizeof(*ctx->keys_seen))) == NULL) 2070 fatal("%s: calloc failed", __func__); 2071 2072 get_hostfile_hostname_ipaddr(host, 2073 options.check_host_ip ? (struct sockaddr *)&hostaddr : NULL, 2074 options.port, &ctx->host_str, 2075 options.check_host_ip ? &ctx->ip_str : NULL); 2076 2077 /* Find which keys we already know about. */ 2078 if ((r = hostkeys_foreach(options.user_hostfiles[0], hostkeys_find, 2079 ctx, ctx->host_str, ctx->ip_str, 2080 HKF_WANT_PARSE_KEY|HKF_WANT_MATCH)) != 0) { 2081 error("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r)); 2082 goto out; 2083 } 2084 2085 /* Figure out if we have any new keys to add */ 2086 ctx->nnew = 0; 2087 for (i = 0; i < ctx->nkeys; i++) { 2088 if (!ctx->keys_seen[i]) 2089 ctx->nnew++; 2090 } 2091 2092 debug3("%s: %zu keys from server: %zu new, %zu retained. %zu to remove", 2093 __func__, ctx->nkeys, ctx->nnew, ctx->nkeys - ctx->nnew, ctx->nold); 2094 2095 if (ctx->nnew == 0 && ctx->nold != 0) { 2096 /* We have some keys to remove. Just do it. */ 2097 update_known_hosts(ctx); 2098 } else if (ctx->nnew != 0) { 2099 /* 2100 * We have received hitherto-unseen keys from the server. 2101 * Ask the server to confirm ownership of the private halves. 2102 */ 2103 debug3("%s: asking server to prove ownership for %zu keys", 2104 __func__, ctx->nnew); 2105 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 2106 (r = sshpkt_put_cstring(ssh, 2107 "hostkeys-prove-00@openssh.com")) != 0 || 2108 (r = sshpkt_put_u8(ssh, 1)) != 0) /* bool: want reply */ 2109 fatal("%s: cannot prepare packet: %s", 2110 __func__, ssh_err(r)); 2111 if ((buf = sshbuf_new()) == NULL) 2112 fatal("%s: sshbuf_new", __func__); 2113 for (i = 0; i < ctx->nkeys; i++) { 2114 if (ctx->keys_seen[i]) 2115 continue; 2116 sshbuf_reset(buf); 2117 if ((r = sshkey_putb(ctx->keys[i], buf)) != 0) 2118 fatal("%s: sshkey_putb: %s", 2119 __func__, ssh_err(r)); 2120 if ((r = sshpkt_put_stringb(ssh, buf)) != 0) 2121 fatal("%s: sshpkt_put_string: %s", 2122 __func__, ssh_err(r)); 2123 } 2124 if ((r = sshpkt_send(ssh)) != 0) 2125 fatal("%s: sshpkt_send: %s", __func__, ssh_err(r)); 2126 client_register_global_confirm( 2127 client_global_hostkeys_private_confirm, ctx); 2128 ctx = NULL; /* will be freed in callback */ 2129 } 2130 2131 /* Success */ 2132 out: 2133 hostkeys_update_ctx_free(ctx); 2134 sshkey_free(key); 2135 sshbuf_free(buf); 2136 /* 2137 * NB. Return success for all cases. The server doesn't need to know 2138 * what the client does with its hosts file. 2139 */ 2140 return 1; 2141 } 2142 2143 static int 2144 client_input_global_request(int type, u_int32_t seq, struct ssh *ssh) 2145 { 2146 char *rtype; 2147 int want_reply; 2148 int success = 0; 2149 2150 rtype = packet_get_cstring(NULL); 2151 want_reply = packet_get_char(); 2152 debug("client_input_global_request: rtype %s want_reply %d", 2153 rtype, want_reply); 2154 if (strcmp(rtype, "hostkeys-00@openssh.com") == 0) 2155 success = client_input_hostkeys(); 2156 if (want_reply) { 2157 packet_start(success ? 2158 SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE); 2159 packet_send(); 2160 packet_write_wait(); 2161 } 2162 free(rtype); 2163 return 0; 2164 } 2165 2166 void 2167 client_session2_setup(struct ssh *ssh, int id, int want_tty, int want_subsystem, 2168 const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env) 2169 { 2170 int len; 2171 Channel *c = NULL; 2172 2173 debug2("%s: id %d", __func__, id); 2174 2175 if ((c = channel_lookup(ssh, id)) == NULL) 2176 fatal("%s: channel %d: unknown channel", __func__, id); 2177 2178 packet_set_interactive(want_tty, 2179 options.ip_qos_interactive, options.ip_qos_bulk); 2180 2181 if (want_tty) { 2182 struct winsize ws; 2183 2184 /* Store window size in the packet. */ 2185 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0) 2186 memset(&ws, 0, sizeof(ws)); 2187 2188 channel_request_start(ssh, id, "pty-req", 1); 2189 client_expect_confirm(ssh, id, "PTY allocation", CONFIRM_TTY); 2190 packet_put_cstring(term != NULL ? term : ""); 2191 packet_put_int((u_int)ws.ws_col); 2192 packet_put_int((u_int)ws.ws_row); 2193 packet_put_int((u_int)ws.ws_xpixel); 2194 packet_put_int((u_int)ws.ws_ypixel); 2195 if (tiop == NULL) 2196 tiop = get_saved_tio(); 2197 tty_make_modes(-1, tiop); 2198 packet_send(); 2199 /* XXX wait for reply */ 2200 c->client_tty = 1; 2201 } 2202 2203 /* Transfer any environment variables from client to server */ 2204 if (options.num_send_env != 0 && env != NULL) { 2205 int i, j, matched; 2206 char *name, *val; 2207 2208 debug("Sending environment."); 2209 for (i = 0; env[i] != NULL; i++) { 2210 /* Split */ 2211 name = xstrdup(env[i]); 2212 if ((val = strchr(name, '=')) == NULL) { 2213 free(name); 2214 continue; 2215 } 2216 *val++ = '\0'; 2217 2218 matched = 0; 2219 for (j = 0; j < options.num_send_env; j++) { 2220 if (match_pattern(name, options.send_env[j])) { 2221 matched = 1; 2222 break; 2223 } 2224 } 2225 if (!matched) { 2226 debug3("Ignored env %s", name); 2227 free(name); 2228 continue; 2229 } 2230 2231 debug("Sending env %s = %s", name, val); 2232 channel_request_start(ssh, id, "env", 0); 2233 packet_put_cstring(name); 2234 packet_put_cstring(val); 2235 packet_send(); 2236 free(name); 2237 } 2238 } 2239 2240 len = buffer_len(cmd); 2241 if (len > 0) { 2242 if (len > 900) 2243 len = 900; 2244 if (want_subsystem) { 2245 debug("Sending subsystem: %.*s", 2246 len, (u_char*)buffer_ptr(cmd)); 2247 channel_request_start(ssh, id, "subsystem", 1); 2248 client_expect_confirm(ssh, id, "subsystem", 2249 CONFIRM_CLOSE); 2250 } else { 2251 debug("Sending command: %.*s", 2252 len, (u_char*)buffer_ptr(cmd)); 2253 channel_request_start(ssh, id, "exec", 1); 2254 client_expect_confirm(ssh, id, "exec", CONFIRM_CLOSE); 2255 } 2256 packet_put_string(buffer_ptr(cmd), buffer_len(cmd)); 2257 packet_send(); 2258 } else { 2259 channel_request_start(ssh, id, "shell", 1); 2260 client_expect_confirm(ssh, id, "shell", CONFIRM_CLOSE); 2261 packet_send(); 2262 } 2263 } 2264 2265 static void 2266 client_init_dispatch(void) 2267 { 2268 dispatch_init(&dispatch_protocol_error); 2269 2270 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); 2271 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); 2272 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); 2273 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); 2274 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open); 2275 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 2276 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 2277 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req); 2278 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); 2279 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm); 2280 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm); 2281 dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request); 2282 2283 /* rekeying */ 2284 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); 2285 2286 /* global request reply messages */ 2287 dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply); 2288 dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply); 2289 } 2290 2291 void 2292 client_stop_mux(void) 2293 { 2294 if (options.control_path != NULL && muxserver_sock != -1) 2295 unlink(options.control_path); 2296 /* 2297 * If we are in persist mode, or don't have a shell, signal that we 2298 * should close when all active channels are closed. 2299 */ 2300 if (options.control_persist || no_shell_flag) { 2301 session_closed = 1; 2302 setproctitle("[stopped mux]"); 2303 } 2304 } 2305 2306 /* client specific fatal cleanup */ 2307 void 2308 cleanup_exit(int i) 2309 { 2310 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 2311 leave_non_blocking(); 2312 if (options.control_path != NULL && muxserver_sock != -1) 2313 unlink(options.control_path); 2314 ssh_kill_proxy_command(); 2315 _exit(i); 2316 } 2317