1 /* $OpenBSD: clientloop.c,v 1.301 2017/07/14 03:18:21 dtucker 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 63 #include <sys/types.h> 64 #include <sys/ioctl.h> 65 #include <sys/stat.h> 66 #include <sys/socket.h> 67 #include <sys/time.h> 68 #include <sys/queue.h> 69 70 #include <ctype.h> 71 #include <errno.h> 72 #include <paths.h> 73 #include <signal.h> 74 #include <stdio.h> 75 #include <stdlib.h> 76 #include <string.h> 77 #include <termios.h> 78 #include <pwd.h> 79 #include <unistd.h> 80 #include <limits.h> 81 82 #include "xmalloc.h" 83 #include "ssh.h" 84 #include "ssh2.h" 85 #include "packet.h" 86 #include "buffer.h" 87 #include "compat.h" 88 #include "channels.h" 89 #include "dispatch.h" 90 #include "key.h" 91 #include "cipher.h" 92 #include "kex.h" 93 #include "myproposal.h" 94 #include "log.h" 95 #include "misc.h" 96 #include "readconf.h" 97 #include "clientloop.h" 98 #include "sshconnect.h" 99 #include "authfd.h" 100 #include "atomicio.h" 101 #include "sshpty.h" 102 #include "match.h" 103 #include "msg.h" 104 #include "ssherr.h" 105 #include "hostfile.h" 106 107 /* import options */ 108 extern Options options; 109 110 /* Flag indicating that stdin should be redirected from /dev/null. */ 111 extern int stdin_null_flag; 112 113 /* Flag indicating that no shell has been requested */ 114 extern int no_shell_flag; 115 116 /* Flag indicating that ssh should daemonise after authentication is complete */ 117 extern int fork_after_authentication_flag; 118 119 /* Control socket */ 120 extern int muxserver_sock; /* XXX use mux_client_cleanup() instead */ 121 122 /* 123 * Name of the host we are connecting to. This is the name given on the 124 * command line, or the HostName specified for the user-supplied name in a 125 * configuration file. 126 */ 127 extern char *host; 128 129 /* 130 * Flag to indicate that we have received a window change signal which has 131 * not yet been processed. This will cause a message indicating the new 132 * window size to be sent to the server a little later. This is volatile 133 * because this is updated in a signal handler. 134 */ 135 static volatile sig_atomic_t received_window_change_signal = 0; 136 static volatile sig_atomic_t received_signal = 0; 137 138 /* Flag indicating whether the user's terminal is in non-blocking mode. */ 139 static int in_non_blocking_mode = 0; 140 141 /* Time when backgrounded control master using ControlPersist should exit */ 142 static time_t control_persist_exit_time = 0; 143 144 /* Common data for the client loop code. */ 145 volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */ 146 static int last_was_cr; /* Last character was a newline. */ 147 static int exit_status; /* Used to store the command exit status. */ 148 static Buffer stderr_buffer; /* Used for final exit message. */ 149 static int connection_in; /* Connection to server (input). */ 150 static int connection_out; /* Connection to server (output). */ 151 static int need_rekeying; /* Set to non-zero if rekeying is requested. */ 152 static int session_closed; /* In SSH2: login session closed. */ 153 static u_int x11_refuse_time; /* If >0, refuse x11 opens after this time. */ 154 155 static void client_init_dispatch(void); 156 int session_ident = -1; 157 158 /* Track escape per proto2 channel */ 159 struct escape_filter_ctx { 160 int escape_pending; 161 int escape_char; 162 }; 163 164 /* Context for channel confirmation replies */ 165 struct channel_reply_ctx { 166 const char *request_type; 167 int id; 168 enum confirm_action action; 169 }; 170 171 /* Global request success/failure callbacks */ 172 struct global_confirm { 173 TAILQ_ENTRY(global_confirm) entry; 174 global_confirm_cb *cb; 175 void *ctx; 176 int ref_count; 177 }; 178 TAILQ_HEAD(global_confirms, global_confirm); 179 static struct global_confirms global_confirms = 180 TAILQ_HEAD_INITIALIZER(global_confirms); 181 182 void ssh_process_session2_setup(int, int, int, Buffer *); 183 184 /* Restores stdin to blocking mode. */ 185 186 static void 187 leave_non_blocking(void) 188 { 189 if (in_non_blocking_mode) { 190 unset_nonblock(fileno(stdin)); 191 in_non_blocking_mode = 0; 192 } 193 } 194 195 /* 196 * Signal handler for the window change signal (SIGWINCH). This just sets a 197 * flag indicating that the window has changed. 198 */ 199 /*ARGSUSED */ 200 static void 201 window_change_handler(int sig) 202 { 203 received_window_change_signal = 1; 204 signal(SIGWINCH, window_change_handler); 205 } 206 207 /* 208 * Signal handler for signals that cause the program to terminate. These 209 * signals must be trapped to restore terminal modes. 210 */ 211 /*ARGSUSED */ 212 static void 213 signal_handler(int sig) 214 { 215 received_signal = sig; 216 quit_pending = 1; 217 } 218 219 /* 220 * Returns current time in seconds from Jan 1, 1970 with the maximum 221 * available resolution. 222 */ 223 224 static double 225 get_current_time(void) 226 { 227 struct timeval tv; 228 gettimeofday(&tv, NULL); 229 return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0; 230 } 231 232 /* 233 * Sets control_persist_exit_time to the absolute time when the 234 * backgrounded control master should exit due to expiry of the 235 * ControlPersist timeout. Sets it to 0 if we are not a backgrounded 236 * control master process, or if there is no ControlPersist timeout. 237 */ 238 static void 239 set_control_persist_exit_time(void) 240 { 241 if (muxserver_sock == -1 || !options.control_persist 242 || options.control_persist_timeout == 0) { 243 /* not using a ControlPersist timeout */ 244 control_persist_exit_time = 0; 245 } else if (channel_still_open()) { 246 /* some client connections are still open */ 247 if (control_persist_exit_time > 0) 248 debug2("%s: cancel scheduled exit", __func__); 249 control_persist_exit_time = 0; 250 } else if (control_persist_exit_time <= 0) { 251 /* a client connection has recently closed */ 252 control_persist_exit_time = monotime() + 253 (time_t)options.control_persist_timeout; 254 debug2("%s: schedule exit in %d seconds", __func__, 255 options.control_persist_timeout); 256 } 257 /* else we are already counting down to the timeout */ 258 } 259 260 #define SSH_X11_VALID_DISPLAY_CHARS ":/.-_" 261 static int 262 client_x11_display_valid(const char *display) 263 { 264 size_t i, dlen; 265 266 if (display == NULL) 267 return 0; 268 269 dlen = strlen(display); 270 for (i = 0; i < dlen; i++) { 271 if (!isalnum((u_char)display[i]) && 272 strchr(SSH_X11_VALID_DISPLAY_CHARS, display[i]) == NULL) { 273 debug("Invalid character '%c' in DISPLAY", display[i]); 274 return 0; 275 } 276 } 277 return 1; 278 } 279 280 #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1" 281 #define X11_TIMEOUT_SLACK 60 282 int 283 client_x11_get_proto(const char *display, const char *xauth_path, 284 u_int trusted, u_int timeout, char **_proto, char **_data) 285 { 286 char cmd[1024], line[512], xdisplay[512]; 287 char xauthfile[PATH_MAX], xauthdir[PATH_MAX]; 288 static char proto[512], data[512]; 289 FILE *f; 290 int got_data = 0, generated = 0, do_unlink = 0, r; 291 struct stat st; 292 u_int now, x11_timeout_real; 293 294 *_proto = proto; 295 *_data = data; 296 proto[0] = data[0] = xauthfile[0] = xauthdir[0] = '\0'; 297 298 if (!client_x11_display_valid(display)) { 299 if (display != NULL) 300 logit("DISPLAY \"%s\" invalid; disabling X11 forwarding", 301 display); 302 return -1; 303 } 304 if (xauth_path != NULL && stat(xauth_path, &st) == -1) { 305 debug("No xauth program."); 306 xauth_path = NULL; 307 } 308 309 if (xauth_path != NULL) { 310 /* 311 * Handle FamilyLocal case where $DISPLAY does 312 * not match an authorization entry. For this we 313 * just try "xauth list unix:displaynum.screennum". 314 * XXX: "localhost" match to determine FamilyLocal 315 * is not perfect. 316 */ 317 if (strncmp(display, "localhost:", 10) == 0) { 318 if ((r = snprintf(xdisplay, sizeof(xdisplay), "unix:%s", 319 display + 10)) < 0 || 320 (size_t)r >= sizeof(xdisplay)) { 321 error("%s: display name too long", __func__); 322 return -1; 323 } 324 display = xdisplay; 325 } 326 if (trusted == 0) { 327 /* 328 * Generate an untrusted X11 auth cookie. 329 * 330 * The authentication cookie should briefly outlive 331 * ssh's willingness to forward X11 connections to 332 * avoid nasty fail-open behaviour in the X server. 333 */ 334 mktemp_proto(xauthdir, sizeof(xauthdir)); 335 if (mkdtemp(xauthdir) == NULL) { 336 error("%s: mkdtemp: %s", 337 __func__, strerror(errno)); 338 return -1; 339 } 340 do_unlink = 1; 341 if ((r = snprintf(xauthfile, sizeof(xauthfile), 342 "%s/xauthfile", xauthdir)) < 0 || 343 (size_t)r >= sizeof(xauthfile)) { 344 error("%s: xauthfile path too long", __func__); 345 unlink(xauthfile); 346 rmdir(xauthdir); 347 return -1; 348 } 349 350 if (timeout >= UINT_MAX - X11_TIMEOUT_SLACK) 351 x11_timeout_real = UINT_MAX; 352 else 353 x11_timeout_real = timeout + X11_TIMEOUT_SLACK; 354 if ((r = snprintf(cmd, sizeof(cmd), 355 "%s -f %s generate %s " SSH_X11_PROTO 356 " untrusted timeout %u 2>" _PATH_DEVNULL, 357 xauth_path, xauthfile, display, 358 x11_timeout_real)) < 0 || 359 (size_t)r >= sizeof(cmd)) 360 fatal("%s: cmd too long", __func__); 361 debug2("%s: %s", __func__, cmd); 362 if (x11_refuse_time == 0) { 363 now = monotime() + 1; 364 if (UINT_MAX - timeout < now) 365 x11_refuse_time = UINT_MAX; 366 else 367 x11_refuse_time = now + timeout; 368 channel_set_x11_refuse_time(x11_refuse_time); 369 } 370 if (system(cmd) == 0) 371 generated = 1; 372 } 373 374 /* 375 * When in untrusted mode, we read the cookie only if it was 376 * successfully generated as an untrusted one in the step 377 * above. 378 */ 379 if (trusted || generated) { 380 snprintf(cmd, sizeof(cmd), 381 "%s %s%s list %s 2>" _PATH_DEVNULL, 382 xauth_path, 383 generated ? "-f " : "" , 384 generated ? xauthfile : "", 385 display); 386 debug2("x11_get_proto: %s", cmd); 387 f = popen(cmd, "r"); 388 if (f && fgets(line, sizeof(line), f) && 389 sscanf(line, "%*s %511s %511s", proto, data) == 2) 390 got_data = 1; 391 if (f) 392 pclose(f); 393 } 394 } 395 396 if (do_unlink) { 397 unlink(xauthfile); 398 rmdir(xauthdir); 399 } 400 401 /* Don't fall back to fake X11 data for untrusted forwarding */ 402 if (!trusted && !got_data) { 403 error("Warning: untrusted X11 forwarding setup failed: " 404 "xauth key data not generated"); 405 return -1; 406 } 407 408 /* 409 * If we didn't get authentication data, just make up some 410 * data. The forwarding code will check the validity of the 411 * response anyway, and substitute this data. The X11 412 * server, however, will ignore this fake data and use 413 * whatever authentication mechanisms it was using otherwise 414 * for the local connection. 415 */ 416 if (!got_data) { 417 u_int8_t rnd[16]; 418 u_int i; 419 420 logit("Warning: No xauth data; " 421 "using fake authentication data for X11 forwarding."); 422 strlcpy(proto, SSH_X11_PROTO, sizeof proto); 423 arc4random_buf(rnd, sizeof(rnd)); 424 for (i = 0; i < sizeof(rnd); i++) { 425 snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", 426 rnd[i]); 427 } 428 } 429 430 return 0; 431 } 432 433 /* 434 * Checks if the client window has changed, and sends a packet about it to 435 * the server if so. The actual change is detected elsewhere (by a software 436 * interrupt on Unix); this just checks the flag and sends a message if 437 * appropriate. 438 */ 439 440 static void 441 client_check_window_change(void) 442 { 443 if (!received_window_change_signal) 444 return; 445 /** XXX race */ 446 received_window_change_signal = 0; 447 448 debug2("%s: changed", __func__); 449 450 channel_send_window_changes(); 451 } 452 453 static int 454 client_global_request_reply(int type, u_int32_t seq, struct ssh *ssh) 455 { 456 struct global_confirm *gc; 457 458 if ((gc = TAILQ_FIRST(&global_confirms)) == NULL) 459 return 0; 460 if (gc->cb != NULL) 461 gc->cb(type, seq, gc->ctx); 462 if (--gc->ref_count <= 0) { 463 TAILQ_REMOVE(&global_confirms, gc, entry); 464 explicit_bzero(gc, sizeof(*gc)); 465 free(gc); 466 } 467 468 packet_set_alive_timeouts(0); 469 return 0; 470 } 471 472 static void 473 server_alive_check(void) 474 { 475 if (packet_inc_alive_timeouts() > options.server_alive_count_max) { 476 logit("Timeout, server %s not responding.", host); 477 cleanup_exit(255); 478 } 479 packet_start(SSH2_MSG_GLOBAL_REQUEST); 480 packet_put_cstring("keepalive@openssh.com"); 481 packet_put_char(1); /* boolean: want reply */ 482 packet_send(); 483 /* Insert an empty placeholder to maintain ordering */ 484 client_register_global_confirm(NULL, NULL); 485 } 486 487 /* 488 * Waits until the client can do something (some data becomes available on 489 * one of the file descriptors). 490 */ 491 static void 492 client_wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, 493 int *maxfdp, u_int *nallocp, int rekeying) 494 { 495 struct timeval tv, *tvp; 496 int timeout_secs; 497 time_t minwait_secs = 0, server_alive_time = 0, now = monotime(); 498 int ret; 499 500 /* Add any selections by the channel mechanism. */ 501 channel_prepare_select(readsetp, writesetp, maxfdp, nallocp, 502 &minwait_secs, rekeying); 503 504 /* channel_prepare_select could have closed the last channel */ 505 if (session_closed && !channel_still_open() && 506 !packet_have_data_to_write()) { 507 /* clear mask since we did not call select() */ 508 memset(*readsetp, 0, *nallocp); 509 memset(*writesetp, 0, *nallocp); 510 return; 511 } 512 513 FD_SET(connection_in, *readsetp); 514 515 /* Select server connection if have data to write to the server. */ 516 if (packet_have_data_to_write()) 517 FD_SET(connection_out, *writesetp); 518 519 /* 520 * Wait for something to happen. This will suspend the process until 521 * some selected descriptor can be read, written, or has some other 522 * event pending, or a timeout expires. 523 */ 524 525 timeout_secs = INT_MAX; /* we use INT_MAX to mean no timeout */ 526 if (options.server_alive_interval > 0) { 527 timeout_secs = options.server_alive_interval; 528 server_alive_time = now + options.server_alive_interval; 529 } 530 if (options.rekey_interval > 0 && !rekeying) 531 timeout_secs = MINIMUM(timeout_secs, packet_get_rekey_timeout()); 532 set_control_persist_exit_time(); 533 if (control_persist_exit_time > 0) { 534 timeout_secs = MINIMUM(timeout_secs, 535 control_persist_exit_time - now); 536 if (timeout_secs < 0) 537 timeout_secs = 0; 538 } 539 if (minwait_secs != 0) 540 timeout_secs = MINIMUM(timeout_secs, (int)minwait_secs); 541 if (timeout_secs == INT_MAX) 542 tvp = NULL; 543 else { 544 tv.tv_sec = timeout_secs; 545 tv.tv_usec = 0; 546 tvp = &tv; 547 } 548 549 ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp); 550 if (ret < 0) { 551 char buf[100]; 552 553 /* 554 * We have to clear the select masks, because we return. 555 * We have to return, because the mainloop checks for the flags 556 * set by the signal handlers. 557 */ 558 memset(*readsetp, 0, *nallocp); 559 memset(*writesetp, 0, *nallocp); 560 561 if (errno == EINTR) 562 return; 563 /* Note: we might still have data in the buffers. */ 564 snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno)); 565 buffer_append(&stderr_buffer, buf, strlen(buf)); 566 quit_pending = 1; 567 } else if (ret == 0) { 568 /* 569 * Timeout. Could have been either keepalive or rekeying. 570 * Keepalive we check here, rekeying is checked in clientloop. 571 */ 572 if (server_alive_time != 0 && server_alive_time <= monotime()) 573 server_alive_check(); 574 } 575 576 } 577 578 static void 579 client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr) 580 { 581 /* Flush stdout and stderr buffers. */ 582 if (buffer_len(bout) > 0) 583 atomicio(vwrite, fileno(stdout), buffer_ptr(bout), 584 buffer_len(bout)); 585 if (buffer_len(berr) > 0) 586 atomicio(vwrite, fileno(stderr), buffer_ptr(berr), 587 buffer_len(berr)); 588 589 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 590 591 /* 592 * Free (and clear) the buffer to reduce the amount of data that gets 593 * written to swap. 594 */ 595 buffer_free(bin); 596 buffer_free(bout); 597 buffer_free(berr); 598 599 /* Send the suspend signal to the program itself. */ 600 kill(getpid(), SIGTSTP); 601 602 /* Reset window sizes in case they have changed */ 603 received_window_change_signal = 1; 604 605 /* OK, we have been continued by the user. Reinitialize buffers. */ 606 buffer_init(bin); 607 buffer_init(bout); 608 buffer_init(berr); 609 610 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 611 } 612 613 static void 614 client_process_net_input(fd_set *readset) 615 { 616 int len; 617 char buf[8192]; 618 619 /* 620 * Read input from the server, and add any such data to the buffer of 621 * the packet subsystem. 622 */ 623 if (FD_ISSET(connection_in, readset)) { 624 /* Read as much as possible. */ 625 len = read(connection_in, buf, sizeof(buf)); 626 if (len == 0) { 627 /* 628 * Received EOF. The remote host has closed the 629 * connection. 630 */ 631 snprintf(buf, sizeof buf, 632 "Connection to %.300s closed by remote host.\r\n", 633 host); 634 buffer_append(&stderr_buffer, buf, strlen(buf)); 635 quit_pending = 1; 636 return; 637 } 638 /* 639 * There is a kernel bug on Solaris that causes select to 640 * sometimes wake up even though there is no data available. 641 */ 642 if (len < 0 && (errno == EAGAIN || errno == EINTR)) 643 len = 0; 644 645 if (len < 0) { 646 /* 647 * An error has encountered. Perhaps there is a 648 * network problem. 649 */ 650 snprintf(buf, sizeof buf, 651 "Read from remote host %.300s: %.100s\r\n", 652 host, strerror(errno)); 653 buffer_append(&stderr_buffer, buf, strlen(buf)); 654 quit_pending = 1; 655 return; 656 } 657 packet_process_incoming(buf, len); 658 } 659 } 660 661 static void 662 client_status_confirm(int type, Channel *c, void *ctx) 663 { 664 struct channel_reply_ctx *cr = (struct channel_reply_ctx *)ctx; 665 char errmsg[256]; 666 int tochan; 667 668 /* 669 * If a TTY was explicitly requested, then a failure to allocate 670 * one is fatal. 671 */ 672 if (cr->action == CONFIRM_TTY && 673 (options.request_tty == REQUEST_TTY_FORCE || 674 options.request_tty == REQUEST_TTY_YES)) 675 cr->action = CONFIRM_CLOSE; 676 677 /* XXX supress on mux _client_ quietmode */ 678 tochan = options.log_level >= SYSLOG_LEVEL_ERROR && 679 c->ctl_chan != -1 && c->extended_usage == CHAN_EXTENDED_WRITE; 680 681 if (type == SSH2_MSG_CHANNEL_SUCCESS) { 682 debug2("%s request accepted on channel %d", 683 cr->request_type, c->self); 684 } else if (type == SSH2_MSG_CHANNEL_FAILURE) { 685 if (tochan) { 686 snprintf(errmsg, sizeof(errmsg), 687 "%s request failed\r\n", cr->request_type); 688 } else { 689 snprintf(errmsg, sizeof(errmsg), 690 "%s request failed on channel %d", 691 cr->request_type, c->self); 692 } 693 /* If error occurred on primary session channel, then exit */ 694 if (cr->action == CONFIRM_CLOSE && c->self == session_ident) 695 fatal("%s", errmsg); 696 /* 697 * If error occurred on mux client, append to 698 * their stderr. 699 */ 700 if (tochan) { 701 buffer_append(&c->extended, errmsg, 702 strlen(errmsg)); 703 } else 704 error("%s", errmsg); 705 if (cr->action == CONFIRM_TTY) { 706 /* 707 * If a TTY allocation error occurred, then arrange 708 * for the correct TTY to leave raw mode. 709 */ 710 if (c->self == session_ident) 711 leave_raw_mode(0); 712 else 713 mux_tty_alloc_failed(c); 714 } else if (cr->action == CONFIRM_CLOSE) { 715 chan_read_failed(c); 716 chan_write_failed(c); 717 } 718 } 719 free(cr); 720 } 721 722 static void 723 client_abandon_status_confirm(Channel *c, void *ctx) 724 { 725 free(ctx); 726 } 727 728 void 729 client_expect_confirm(int id, const char *request, 730 enum confirm_action action) 731 { 732 struct channel_reply_ctx *cr = xcalloc(1, sizeof(*cr)); 733 734 cr->request_type = request; 735 cr->action = action; 736 737 channel_register_status_confirm(id, client_status_confirm, 738 client_abandon_status_confirm, cr); 739 } 740 741 void 742 client_register_global_confirm(global_confirm_cb *cb, void *ctx) 743 { 744 struct global_confirm *gc, *last_gc; 745 746 /* Coalesce identical callbacks */ 747 last_gc = TAILQ_LAST(&global_confirms, global_confirms); 748 if (last_gc && last_gc->cb == cb && last_gc->ctx == ctx) { 749 if (++last_gc->ref_count >= INT_MAX) 750 fatal("%s: last_gc->ref_count = %d", 751 __func__, last_gc->ref_count); 752 return; 753 } 754 755 gc = xcalloc(1, sizeof(*gc)); 756 gc->cb = cb; 757 gc->ctx = ctx; 758 gc->ref_count = 1; 759 TAILQ_INSERT_TAIL(&global_confirms, gc, entry); 760 } 761 762 static void 763 process_cmdline(void) 764 { 765 void (*handler)(int); 766 char *s, *cmd; 767 int ok, delete = 0, local = 0, remote = 0, dynamic = 0; 768 struct Forward fwd; 769 770 memset(&fwd, 0, sizeof(fwd)); 771 772 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 773 handler = signal(SIGINT, SIG_IGN); 774 cmd = s = read_passphrase("\r\nssh> ", RP_ECHO); 775 if (s == NULL) 776 goto out; 777 while (isspace((u_char)*s)) 778 s++; 779 if (*s == '-') 780 s++; /* Skip cmdline '-', if any */ 781 if (*s == '\0') 782 goto out; 783 784 if (*s == 'h' || *s == 'H' || *s == '?') { 785 logit("Commands:"); 786 logit(" -L[bind_address:]port:host:hostport " 787 "Request local forward"); 788 logit(" -R[bind_address:]port:host:hostport " 789 "Request remote forward"); 790 logit(" -D[bind_address:]port " 791 "Request dynamic forward"); 792 logit(" -KL[bind_address:]port " 793 "Cancel local forward"); 794 logit(" -KR[bind_address:]port " 795 "Cancel remote forward"); 796 logit(" -KD[bind_address:]port " 797 "Cancel dynamic forward"); 798 if (!options.permit_local_command) 799 goto out; 800 logit(" !args " 801 "Execute local command"); 802 goto out; 803 } 804 805 if (*s == '!' && options.permit_local_command) { 806 s++; 807 ssh_local_cmd(s); 808 goto out; 809 } 810 811 if (*s == 'K') { 812 delete = 1; 813 s++; 814 } 815 if (*s == 'L') 816 local = 1; 817 else if (*s == 'R') 818 remote = 1; 819 else if (*s == 'D') 820 dynamic = 1; 821 else { 822 logit("Invalid command."); 823 goto out; 824 } 825 826 while (isspace((u_char)*++s)) 827 ; 828 829 /* XXX update list of forwards in options */ 830 if (delete) { 831 /* We pass 1 for dynamicfwd to restrict to 1 or 2 fields. */ 832 if (!parse_forward(&fwd, s, 1, 0)) { 833 logit("Bad forwarding close specification."); 834 goto out; 835 } 836 if (remote) 837 ok = channel_request_rforward_cancel(&fwd) == 0; 838 else if (dynamic) 839 ok = channel_cancel_lport_listener(&fwd, 840 0, &options.fwd_opts) > 0; 841 else 842 ok = channel_cancel_lport_listener(&fwd, 843 CHANNEL_CANCEL_PORT_STATIC, 844 &options.fwd_opts) > 0; 845 if (!ok) { 846 logit("Unknown port forwarding."); 847 goto out; 848 } 849 logit("Canceled forwarding."); 850 } else { 851 if (!parse_forward(&fwd, s, dynamic, remote)) { 852 logit("Bad forwarding specification."); 853 goto out; 854 } 855 if (local || dynamic) { 856 if (!channel_setup_local_fwd_listener(&fwd, 857 &options.fwd_opts)) { 858 logit("Port forwarding failed."); 859 goto out; 860 } 861 } else { 862 if (channel_request_remote_forwarding(&fwd) < 0) { 863 logit("Port forwarding failed."); 864 goto out; 865 } 866 } 867 logit("Forwarding port."); 868 } 869 870 out: 871 signal(SIGINT, handler); 872 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 873 free(cmd); 874 free(fwd.listen_host); 875 free(fwd.listen_path); 876 free(fwd.connect_host); 877 free(fwd.connect_path); 878 } 879 880 /* reasons to suppress output of an escape command in help output */ 881 #define SUPPRESS_NEVER 0 /* never suppress, always show */ 882 #define SUPPRESS_MUXCLIENT 1 /* don't show in mux client sessions */ 883 #define SUPPRESS_MUXMASTER 2 /* don't show in mux master sessions */ 884 #define SUPPRESS_SYSLOG 4 /* don't show when logging to syslog */ 885 struct escape_help_text { 886 const char *cmd; 887 const char *text; 888 unsigned int flags; 889 }; 890 static struct escape_help_text esc_txt[] = { 891 {".", "terminate session", SUPPRESS_MUXMASTER}, 892 {".", "terminate connection (and any multiplexed sessions)", 893 SUPPRESS_MUXCLIENT}, 894 {"B", "send a BREAK to the remote system", SUPPRESS_NEVER}, 895 {"C", "open a command line", SUPPRESS_MUXCLIENT}, 896 {"R", "request rekey", SUPPRESS_NEVER}, 897 {"V/v", "decrease/increase verbosity (LogLevel)", SUPPRESS_MUXCLIENT}, 898 {"^Z", "suspend ssh", SUPPRESS_MUXCLIENT}, 899 {"#", "list forwarded connections", SUPPRESS_NEVER}, 900 {"&", "background ssh (when waiting for connections to terminate)", 901 SUPPRESS_MUXCLIENT}, 902 {"?", "this message", SUPPRESS_NEVER}, 903 }; 904 905 static void 906 print_escape_help(Buffer *b, int escape_char, int mux_client, int using_stderr) 907 { 908 unsigned int i, suppress_flags; 909 char string[1024]; 910 911 snprintf(string, sizeof string, "%c?\r\n" 912 "Supported escape sequences:\r\n", escape_char); 913 buffer_append(b, string, strlen(string)); 914 915 suppress_flags = 916 (mux_client ? SUPPRESS_MUXCLIENT : 0) | 917 (mux_client ? 0 : SUPPRESS_MUXMASTER) | 918 (using_stderr ? 0 : SUPPRESS_SYSLOG); 919 920 for (i = 0; i < sizeof(esc_txt)/sizeof(esc_txt[0]); i++) { 921 if (esc_txt[i].flags & suppress_flags) 922 continue; 923 snprintf(string, sizeof string, " %c%-3s - %s\r\n", 924 escape_char, esc_txt[i].cmd, esc_txt[i].text); 925 buffer_append(b, string, strlen(string)); 926 } 927 928 snprintf(string, sizeof string, 929 " %c%c - send the escape character by typing it twice\r\n" 930 "(Note that escapes are only recognized immediately after " 931 "newline.)\r\n", escape_char, escape_char); 932 buffer_append(b, string, strlen(string)); 933 } 934 935 /* 936 * Process the characters one by one. 937 */ 938 static int 939 process_escapes(Channel *c, Buffer *bin, Buffer *bout, Buffer *berr, 940 char *buf, int len) 941 { 942 char string[1024]; 943 pid_t pid; 944 int bytes = 0; 945 u_int i; 946 u_char ch; 947 char *s; 948 struct escape_filter_ctx *efc = c->filter_ctx == NULL ? 949 NULL : (struct escape_filter_ctx *)c->filter_ctx; 950 951 if (c->filter_ctx == NULL) 952 return 0; 953 954 if (len <= 0) 955 return (0); 956 957 for (i = 0; i < (u_int)len; i++) { 958 /* Get one character at a time. */ 959 ch = buf[i]; 960 961 if (efc->escape_pending) { 962 /* We have previously seen an escape character. */ 963 /* Clear the flag now. */ 964 efc->escape_pending = 0; 965 966 /* Process the escaped character. */ 967 switch (ch) { 968 case '.': 969 /* Terminate the connection. */ 970 snprintf(string, sizeof string, "%c.\r\n", 971 efc->escape_char); 972 buffer_append(berr, string, strlen(string)); 973 974 if (c && c->ctl_chan != -1) { 975 chan_read_failed(c); 976 chan_write_failed(c); 977 if (c->detach_user) 978 c->detach_user(c->self, NULL); 979 c->type = SSH_CHANNEL_ABANDONED; 980 buffer_clear(&c->input); 981 chan_ibuf_empty(c); 982 return 0; 983 } else 984 quit_pending = 1; 985 return -1; 986 987 case 'Z' - 64: 988 /* XXX support this for mux clients */ 989 if (c && c->ctl_chan != -1) { 990 char b[16]; 991 noescape: 992 if (ch == 'Z' - 64) 993 snprintf(b, sizeof b, "^Z"); 994 else 995 snprintf(b, sizeof b, "%c", ch); 996 snprintf(string, sizeof string, 997 "%c%s escape not available to " 998 "multiplexed sessions\r\n", 999 efc->escape_char, b); 1000 buffer_append(berr, string, 1001 strlen(string)); 1002 continue; 1003 } 1004 /* Suspend the program. Inform the user */ 1005 snprintf(string, sizeof string, 1006 "%c^Z [suspend ssh]\r\n", efc->escape_char); 1007 buffer_append(berr, string, strlen(string)); 1008 1009 /* Restore terminal modes and suspend. */ 1010 client_suspend_self(bin, bout, berr); 1011 1012 /* We have been continued. */ 1013 continue; 1014 1015 case 'B': 1016 snprintf(string, sizeof string, 1017 "%cB\r\n", efc->escape_char); 1018 buffer_append(berr, string, strlen(string)); 1019 channel_request_start(c->self, "break", 0); 1020 packet_put_int(1000); 1021 packet_send(); 1022 continue; 1023 1024 case 'R': 1025 if (datafellows & SSH_BUG_NOREKEY) 1026 logit("Server does not " 1027 "support re-keying"); 1028 else 1029 need_rekeying = 1; 1030 continue; 1031 1032 case 'V': 1033 /* FALLTHROUGH */ 1034 case 'v': 1035 if (c && c->ctl_chan != -1) 1036 goto noescape; 1037 if (!log_is_on_stderr()) { 1038 snprintf(string, sizeof string, 1039 "%c%c [Logging to syslog]\r\n", 1040 efc->escape_char, ch); 1041 buffer_append(berr, string, 1042 strlen(string)); 1043 continue; 1044 } 1045 if (ch == 'V' && options.log_level > 1046 SYSLOG_LEVEL_QUIET) 1047 log_change_level(--options.log_level); 1048 if (ch == 'v' && options.log_level < 1049 SYSLOG_LEVEL_DEBUG3) 1050 log_change_level(++options.log_level); 1051 snprintf(string, sizeof string, 1052 "%c%c [LogLevel %s]\r\n", 1053 efc->escape_char, ch, 1054 log_level_name(options.log_level)); 1055 buffer_append(berr, string, strlen(string)); 1056 continue; 1057 1058 case '&': 1059 if (c && c->ctl_chan != -1) 1060 goto noescape; 1061 /* 1062 * Detach the program (continue to serve 1063 * connections, but put in background and no 1064 * more new connections). 1065 */ 1066 /* Restore tty modes. */ 1067 leave_raw_mode( 1068 options.request_tty == REQUEST_TTY_FORCE); 1069 1070 /* Stop listening for new connections. */ 1071 channel_stop_listening(); 1072 1073 snprintf(string, sizeof string, 1074 "%c& [backgrounded]\n", efc->escape_char); 1075 buffer_append(berr, string, strlen(string)); 1076 1077 /* Fork into background. */ 1078 pid = fork(); 1079 if (pid < 0) { 1080 error("fork: %.100s", strerror(errno)); 1081 continue; 1082 } 1083 if (pid != 0) { /* This is the parent. */ 1084 /* The parent just exits. */ 1085 exit(0); 1086 } 1087 /* The child continues serving connections. */ 1088 buffer_append(bin, "\004", 1); 1089 /* fake EOF on stdin */ 1090 return -1; 1091 case '?': 1092 print_escape_help(berr, efc->escape_char, 1093 (c && c->ctl_chan != -1), 1094 log_is_on_stderr()); 1095 continue; 1096 1097 case '#': 1098 snprintf(string, sizeof string, "%c#\r\n", 1099 efc->escape_char); 1100 buffer_append(berr, string, strlen(string)); 1101 s = channel_open_message(); 1102 buffer_append(berr, s, strlen(s)); 1103 free(s); 1104 continue; 1105 1106 case 'C': 1107 if (c && c->ctl_chan != -1) 1108 goto noescape; 1109 process_cmdline(); 1110 continue; 1111 1112 default: 1113 if (ch != efc->escape_char) { 1114 buffer_put_char(bin, efc->escape_char); 1115 bytes++; 1116 } 1117 /* Escaped characters fall through here */ 1118 break; 1119 } 1120 } else { 1121 /* 1122 * The previous character was not an escape char. 1123 * Check if this is an escape. 1124 */ 1125 if (last_was_cr && ch == efc->escape_char) { 1126 /* 1127 * It is. Set the flag and continue to 1128 * next character. 1129 */ 1130 efc->escape_pending = 1; 1131 continue; 1132 } 1133 } 1134 1135 /* 1136 * Normal character. Record whether it was a newline, 1137 * and append it to the buffer. 1138 */ 1139 last_was_cr = (ch == '\r' || ch == '\n'); 1140 buffer_put_char(bin, ch); 1141 bytes++; 1142 } 1143 return bytes; 1144 } 1145 1146 /* 1147 * Get packets from the connection input buffer, and process them as long as 1148 * there are packets available. 1149 * 1150 * Any unknown packets received during the actual 1151 * session cause the session to terminate. This is 1152 * intended to make debugging easier since no 1153 * confirmations are sent. Any compatible protocol 1154 * extensions must be negotiated during the 1155 * preparatory phase. 1156 */ 1157 1158 static void 1159 client_process_buffered_input_packets(void) 1160 { 1161 ssh_dispatch_run_fatal(active_state, DISPATCH_NONBLOCK, &quit_pending); 1162 } 1163 1164 /* scan buf[] for '~' before sending data to the peer */ 1165 1166 /* Helper: allocate a new escape_filter_ctx and fill in its escape char */ 1167 void * 1168 client_new_escape_filter_ctx(int escape_char) 1169 { 1170 struct escape_filter_ctx *ret; 1171 1172 ret = xcalloc(1, sizeof(*ret)); 1173 ret->escape_pending = 0; 1174 ret->escape_char = escape_char; 1175 return (void *)ret; 1176 } 1177 1178 /* Free the escape filter context on channel free */ 1179 void 1180 client_filter_cleanup(int cid, void *ctx) 1181 { 1182 free(ctx); 1183 } 1184 1185 int 1186 client_simple_escape_filter(Channel *c, char *buf, int len) 1187 { 1188 if (c->extended_usage != CHAN_EXTENDED_WRITE) 1189 return 0; 1190 1191 return process_escapes(c, &c->input, &c->output, &c->extended, 1192 buf, len); 1193 } 1194 1195 static void 1196 client_channel_closed(int id, void *arg) 1197 { 1198 channel_cancel_cleanup(id); 1199 session_closed = 1; 1200 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1201 } 1202 1203 /* 1204 * Implements the interactive session with the server. This is called after 1205 * the user has been authenticated, and a command has been started on the 1206 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character 1207 * used as an escape character for terminating or suspending the session. 1208 */ 1209 1210 int 1211 client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id) 1212 { 1213 fd_set *readset = NULL, *writeset = NULL; 1214 double start_time, total_time; 1215 int r, max_fd = 0, max_fd2 = 0, len; 1216 u_int64_t ibytes, obytes; 1217 u_int nalloc = 0; 1218 char buf[100]; 1219 1220 debug("Entering interactive session."); 1221 1222 if (options.control_master && 1223 !option_clear_or_none(options.control_path)) { 1224 debug("pledge: id"); 1225 if (pledge("stdio rpath wpath cpath unix inet dns recvfd proc exec id tty", 1226 NULL) == -1) 1227 fatal("%s pledge(): %s", __func__, strerror(errno)); 1228 1229 } else if (options.forward_x11 || options.permit_local_command) { 1230 debug("pledge: exec"); 1231 if (pledge("stdio rpath wpath cpath unix inet dns proc exec tty", 1232 NULL) == -1) 1233 fatal("%s pledge(): %s", __func__, strerror(errno)); 1234 1235 } else if (options.update_hostkeys) { 1236 debug("pledge: filesystem full"); 1237 if (pledge("stdio rpath wpath cpath unix inet dns proc tty", 1238 NULL) == -1) 1239 fatal("%s pledge(): %s", __func__, strerror(errno)); 1240 1241 } else if (!option_clear_or_none(options.proxy_command) || 1242 fork_after_authentication_flag) { 1243 debug("pledge: proc"); 1244 if (pledge("stdio cpath unix inet dns proc tty", NULL) == -1) 1245 fatal("%s pledge(): %s", __func__, strerror(errno)); 1246 1247 } else { 1248 debug("pledge: network"); 1249 if (pledge("stdio unix inet dns proc tty", NULL) == -1) 1250 fatal("%s pledge(): %s", __func__, strerror(errno)); 1251 } 1252 1253 start_time = get_current_time(); 1254 1255 /* Initialize variables. */ 1256 last_was_cr = 1; 1257 exit_status = -1; 1258 connection_in = packet_get_connection_in(); 1259 connection_out = packet_get_connection_out(); 1260 max_fd = MAXIMUM(connection_in, connection_out); 1261 1262 quit_pending = 0; 1263 1264 /* Initialize buffers. */ 1265 buffer_init(&stderr_buffer); 1266 1267 client_init_dispatch(); 1268 1269 /* 1270 * Set signal handlers, (e.g. to restore non-blocking mode) 1271 * but don't overwrite SIG_IGN, matches behaviour from rsh(1) 1272 */ 1273 if (signal(SIGHUP, SIG_IGN) != SIG_IGN) 1274 signal(SIGHUP, signal_handler); 1275 if (signal(SIGINT, SIG_IGN) != SIG_IGN) 1276 signal(SIGINT, signal_handler); 1277 if (signal(SIGQUIT, SIG_IGN) != SIG_IGN) 1278 signal(SIGQUIT, signal_handler); 1279 if (signal(SIGTERM, SIG_IGN) != SIG_IGN) 1280 signal(SIGTERM, signal_handler); 1281 signal(SIGWINCH, window_change_handler); 1282 1283 if (have_pty) 1284 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1285 1286 session_ident = ssh2_chan_id; 1287 if (session_ident != -1) { 1288 if (escape_char_arg != SSH_ESCAPECHAR_NONE) { 1289 channel_register_filter(session_ident, 1290 client_simple_escape_filter, NULL, 1291 client_filter_cleanup, 1292 client_new_escape_filter_ctx( 1293 escape_char_arg)); 1294 } 1295 channel_register_cleanup(session_ident, 1296 client_channel_closed, 0); 1297 } 1298 1299 /* Main loop of the client for the interactive session mode. */ 1300 while (!quit_pending) { 1301 1302 /* Process buffered packets sent by the server. */ 1303 client_process_buffered_input_packets(); 1304 1305 if (session_closed && !channel_still_open()) 1306 break; 1307 1308 if (ssh_packet_is_rekeying(active_state)) { 1309 debug("rekeying in progress"); 1310 } else if (need_rekeying) { 1311 /* manual rekey request */ 1312 debug("need rekeying"); 1313 if ((r = kex_start_rekex(active_state)) != 0) 1314 fatal("%s: kex_start_rekex: %s", __func__, 1315 ssh_err(r)); 1316 need_rekeying = 0; 1317 } else { 1318 /* 1319 * Make packets from buffered channel data, and 1320 * enqueue them for sending to the server. 1321 */ 1322 if (packet_not_very_much_data_to_write()) 1323 channel_output_poll(); 1324 1325 /* 1326 * Check if the window size has changed, and buffer a 1327 * message about it to the server if so. 1328 */ 1329 client_check_window_change(); 1330 1331 if (quit_pending) 1332 break; 1333 } 1334 /* 1335 * Wait until we have something to do (something becomes 1336 * available on one of the descriptors). 1337 */ 1338 max_fd2 = max_fd; 1339 client_wait_until_can_do_something(&readset, &writeset, 1340 &max_fd2, &nalloc, ssh_packet_is_rekeying(active_state)); 1341 1342 if (quit_pending) 1343 break; 1344 1345 /* Do channel operations unless rekeying in progress. */ 1346 if (!ssh_packet_is_rekeying(active_state)) 1347 channel_after_select(readset, writeset); 1348 1349 /* Buffer input from the connection. */ 1350 client_process_net_input(readset); 1351 1352 if (quit_pending) 1353 break; 1354 1355 /* 1356 * Send as much buffered packet data as possible to the 1357 * sender. 1358 */ 1359 if (FD_ISSET(connection_out, writeset)) 1360 packet_write_poll(); 1361 1362 /* 1363 * If we are a backgrounded control master, and the 1364 * timeout has expired without any active client 1365 * connections, then quit. 1366 */ 1367 if (control_persist_exit_time > 0) { 1368 if (monotime() >= control_persist_exit_time) { 1369 debug("ControlPersist timeout expired"); 1370 break; 1371 } 1372 } 1373 } 1374 free(readset); 1375 free(writeset); 1376 1377 /* Terminate the session. */ 1378 1379 /* Stop watching for window change. */ 1380 signal(SIGWINCH, SIG_DFL); 1381 1382 packet_start(SSH2_MSG_DISCONNECT); 1383 packet_put_int(SSH2_DISCONNECT_BY_APPLICATION); 1384 packet_put_cstring("disconnected by user"); 1385 packet_put_cstring(""); /* language tag */ 1386 packet_send(); 1387 packet_write_wait(); 1388 1389 channel_free_all(); 1390 1391 if (have_pty) 1392 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1393 1394 /* restore blocking io */ 1395 if (!isatty(fileno(stdin))) 1396 unset_nonblock(fileno(stdin)); 1397 if (!isatty(fileno(stdout))) 1398 unset_nonblock(fileno(stdout)); 1399 if (!isatty(fileno(stderr))) 1400 unset_nonblock(fileno(stderr)); 1401 1402 /* 1403 * If there was no shell or command requested, there will be no remote 1404 * exit status to be returned. In that case, clear error code if the 1405 * connection was deliberately terminated at this end. 1406 */ 1407 if (no_shell_flag && received_signal == SIGTERM) { 1408 received_signal = 0; 1409 exit_status = 0; 1410 } 1411 1412 if (received_signal) { 1413 verbose("Killed by signal %d.", (int) received_signal); 1414 cleanup_exit(0); 1415 } 1416 1417 /* 1418 * In interactive mode (with pseudo tty) display a message indicating 1419 * that the connection has been closed. 1420 */ 1421 if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) { 1422 snprintf(buf, sizeof buf, 1423 "Connection to %.64s closed.\r\n", host); 1424 buffer_append(&stderr_buffer, buf, strlen(buf)); 1425 } 1426 1427 /* Output any buffered data for stderr. */ 1428 if (buffer_len(&stderr_buffer) > 0) { 1429 len = atomicio(vwrite, fileno(stderr), 1430 buffer_ptr(&stderr_buffer), buffer_len(&stderr_buffer)); 1431 if (len < 0 || (u_int)len != buffer_len(&stderr_buffer)) 1432 error("Write failed flushing stderr buffer."); 1433 else 1434 buffer_consume(&stderr_buffer, len); 1435 } 1436 1437 /* Clear and free any buffers. */ 1438 explicit_bzero(buf, sizeof(buf)); 1439 buffer_free(&stderr_buffer); 1440 1441 /* Report bytes transferred, and transfer rates. */ 1442 total_time = get_current_time() - start_time; 1443 packet_get_bytes(&ibytes, &obytes); 1444 verbose("Transferred: sent %llu, received %llu bytes, in %.1f seconds", 1445 (unsigned long long)obytes, (unsigned long long)ibytes, total_time); 1446 if (total_time > 0) 1447 verbose("Bytes per second: sent %.1f, received %.1f", 1448 obytes / total_time, ibytes / total_time); 1449 /* Return the exit status of the program. */ 1450 debug("Exit status %d", exit_status); 1451 return exit_status; 1452 } 1453 1454 /*********/ 1455 1456 static Channel * 1457 client_request_forwarded_tcpip(const char *request_type, int rchan, 1458 u_int rwindow, u_int rmaxpack) 1459 { 1460 Channel *c = NULL; 1461 struct sshbuf *b = NULL; 1462 char *listen_address, *originator_address; 1463 u_short listen_port, originator_port; 1464 int r; 1465 1466 /* Get rest of the packet */ 1467 listen_address = packet_get_string(NULL); 1468 listen_port = packet_get_int(); 1469 originator_address = packet_get_string(NULL); 1470 originator_port = packet_get_int(); 1471 packet_check_eom(); 1472 1473 debug("%s: listen %s port %d, originator %s port %d", __func__, 1474 listen_address, listen_port, originator_address, originator_port); 1475 1476 c = channel_connect_by_listen_address(listen_address, listen_port, 1477 "forwarded-tcpip", originator_address); 1478 1479 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) { 1480 if ((b = sshbuf_new()) == NULL) { 1481 error("%s: alloc reply", __func__); 1482 goto out; 1483 } 1484 /* reconstruct and send to muxclient */ 1485 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 1486 (r = sshbuf_put_u8(b, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1487 (r = sshbuf_put_cstring(b, request_type)) != 0 || 1488 (r = sshbuf_put_u32(b, rchan)) != 0 || 1489 (r = sshbuf_put_u32(b, rwindow)) != 0 || 1490 (r = sshbuf_put_u32(b, rmaxpack)) != 0 || 1491 (r = sshbuf_put_cstring(b, listen_address)) != 0 || 1492 (r = sshbuf_put_u32(b, listen_port)) != 0 || 1493 (r = sshbuf_put_cstring(b, originator_address)) != 0 || 1494 (r = sshbuf_put_u32(b, originator_port)) != 0 || 1495 (r = sshbuf_put_stringb(&c->output, b)) != 0) { 1496 error("%s: compose for muxclient %s", __func__, 1497 ssh_err(r)); 1498 goto out; 1499 } 1500 } 1501 1502 out: 1503 sshbuf_free(b); 1504 free(originator_address); 1505 free(listen_address); 1506 return c; 1507 } 1508 1509 static Channel * 1510 client_request_forwarded_streamlocal(const char *request_type, int rchan) 1511 { 1512 Channel *c = NULL; 1513 char *listen_path; 1514 1515 /* Get the remote path. */ 1516 listen_path = packet_get_string(NULL); 1517 /* XXX: Skip reserved field for now. */ 1518 if (packet_get_string_ptr(NULL) == NULL) 1519 fatal("%s: packet_get_string_ptr failed", __func__); 1520 packet_check_eom(); 1521 1522 debug("%s: %s", __func__, listen_path); 1523 1524 c = channel_connect_by_listen_path(listen_path, 1525 "forwarded-streamlocal@openssh.com", "forwarded-streamlocal"); 1526 free(listen_path); 1527 return c; 1528 } 1529 1530 static Channel * 1531 client_request_x11(const char *request_type, int rchan) 1532 { 1533 Channel *c = NULL; 1534 char *originator; 1535 u_short originator_port; 1536 int sock; 1537 1538 if (!options.forward_x11) { 1539 error("Warning: ssh server tried X11 forwarding."); 1540 error("Warning: this is probably a break-in attempt by a " 1541 "malicious server."); 1542 return NULL; 1543 } 1544 if (x11_refuse_time != 0 && (u_int)monotime() >= x11_refuse_time) { 1545 verbose("Rejected X11 connection after ForwardX11Timeout " 1546 "expired"); 1547 return NULL; 1548 } 1549 originator = packet_get_string(NULL); 1550 if (datafellows & SSH_BUG_X11FWD) { 1551 debug2("buggy server: x11 request w/o originator_port"); 1552 originator_port = 0; 1553 } else { 1554 originator_port = packet_get_int(); 1555 } 1556 packet_check_eom(); 1557 /* XXX check permission */ 1558 debug("client_request_x11: request from %s %d", originator, 1559 originator_port); 1560 free(originator); 1561 sock = x11_connect_display(); 1562 if (sock < 0) 1563 return NULL; 1564 c = channel_new("x11", 1565 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1566 CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); 1567 c->force_drain = 1; 1568 return c; 1569 } 1570 1571 static Channel * 1572 client_request_agent(const char *request_type, int rchan) 1573 { 1574 Channel *c = NULL; 1575 int r, sock; 1576 1577 if (!options.forward_agent) { 1578 error("Warning: ssh server tried agent forwarding."); 1579 error("Warning: this is probably a break-in attempt by a " 1580 "malicious server."); 1581 return NULL; 1582 } 1583 if ((r = ssh_get_authentication_socket(&sock)) != 0) { 1584 if (r != SSH_ERR_AGENT_NOT_PRESENT) 1585 debug("%s: ssh_get_authentication_socket: %s", 1586 __func__, ssh_err(r)); 1587 return NULL; 1588 } 1589 c = channel_new("authentication agent connection", 1590 SSH_CHANNEL_OPEN, sock, sock, -1, 1591 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, 1592 "authentication agent connection", 1); 1593 c->force_drain = 1; 1594 return c; 1595 } 1596 1597 int 1598 client_request_tun_fwd(int tun_mode, int local_tun, int remote_tun) 1599 { 1600 Channel *c; 1601 int fd; 1602 1603 if (tun_mode == SSH_TUNMODE_NO) 1604 return 0; 1605 1606 debug("Requesting tun unit %d in mode %d", local_tun, tun_mode); 1607 1608 /* Open local tunnel device */ 1609 if ((fd = tun_open(local_tun, tun_mode)) == -1) { 1610 error("Tunnel device open failed."); 1611 return -1; 1612 } 1613 1614 c = channel_new("tun", SSH_CHANNEL_OPENING, fd, fd, -1, 1615 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1); 1616 c->datagram = 1; 1617 1618 packet_start(SSH2_MSG_CHANNEL_OPEN); 1619 packet_put_cstring("tun@openssh.com"); 1620 packet_put_int(c->self); 1621 packet_put_int(c->local_window_max); 1622 packet_put_int(c->local_maxpacket); 1623 packet_put_int(tun_mode); 1624 packet_put_int(remote_tun); 1625 packet_send(); 1626 1627 return 0; 1628 } 1629 1630 /* XXXX move to generic input handler */ 1631 static int 1632 client_input_channel_open(int type, u_int32_t seq, struct ssh *ssh) 1633 { 1634 Channel *c = NULL; 1635 char *ctype; 1636 int rchan; 1637 u_int rmaxpack, rwindow, len; 1638 1639 ctype = packet_get_string(&len); 1640 rchan = packet_get_int(); 1641 rwindow = packet_get_int(); 1642 rmaxpack = packet_get_int(); 1643 1644 debug("client_input_channel_open: ctype %s rchan %d win %d max %d", 1645 ctype, rchan, rwindow, rmaxpack); 1646 1647 if (strcmp(ctype, "forwarded-tcpip") == 0) { 1648 c = client_request_forwarded_tcpip(ctype, rchan, rwindow, 1649 rmaxpack); 1650 } else if (strcmp(ctype, "forwarded-streamlocal@openssh.com") == 0) { 1651 c = client_request_forwarded_streamlocal(ctype, rchan); 1652 } else if (strcmp(ctype, "x11") == 0) { 1653 c = client_request_x11(ctype, rchan); 1654 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) { 1655 c = client_request_agent(ctype, rchan); 1656 } 1657 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) { 1658 debug3("proxied to downstream: %s", ctype); 1659 } else if (c != NULL) { 1660 debug("confirm %s", ctype); 1661 c->remote_id = rchan; 1662 c->remote_window = rwindow; 1663 c->remote_maxpacket = rmaxpack; 1664 if (c->type != SSH_CHANNEL_CONNECTING) { 1665 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); 1666 packet_put_int(c->remote_id); 1667 packet_put_int(c->self); 1668 packet_put_int(c->local_window); 1669 packet_put_int(c->local_maxpacket); 1670 packet_send(); 1671 } 1672 } else { 1673 debug("failure %s", ctype); 1674 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); 1675 packet_put_int(rchan); 1676 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED); 1677 if (!(datafellows & SSH_BUG_OPENFAILURE)) { 1678 packet_put_cstring("open failed"); 1679 packet_put_cstring(""); 1680 } 1681 packet_send(); 1682 } 1683 free(ctype); 1684 return 0; 1685 } 1686 1687 static int 1688 client_input_channel_req(int type, u_int32_t seq, struct ssh *ssh) 1689 { 1690 Channel *c = NULL; 1691 int exitval, id, reply, success = 0; 1692 char *rtype; 1693 1694 id = packet_get_int(); 1695 c = channel_lookup(id); 1696 if (channel_proxy_upstream(c, type, seq, ssh)) 1697 return 0; 1698 rtype = packet_get_string(NULL); 1699 reply = packet_get_char(); 1700 1701 debug("client_input_channel_req: channel %d rtype %s reply %d", 1702 id, rtype, reply); 1703 1704 if (id == -1) { 1705 error("client_input_channel_req: request for channel -1"); 1706 } else if (c == NULL) { 1707 error("client_input_channel_req: channel %d: " 1708 "unknown channel", id); 1709 } else if (strcmp(rtype, "eow@openssh.com") == 0) { 1710 packet_check_eom(); 1711 chan_rcvd_eow(c); 1712 } else if (strcmp(rtype, "exit-status") == 0) { 1713 exitval = packet_get_int(); 1714 if (c->ctl_chan != -1) { 1715 mux_exit_message(c, exitval); 1716 success = 1; 1717 } else if (id == session_ident) { 1718 /* Record exit value of local session */ 1719 success = 1; 1720 exit_status = exitval; 1721 } else { 1722 /* Probably for a mux channel that has already closed */ 1723 debug("%s: no sink for exit-status on channel %d", 1724 __func__, id); 1725 } 1726 packet_check_eom(); 1727 } 1728 if (reply && c != NULL && !(c->flags & CHAN_CLOSE_SENT)) { 1729 packet_start(success ? 1730 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE); 1731 packet_put_int(c->remote_id); 1732 packet_send(); 1733 } 1734 free(rtype); 1735 return 0; 1736 } 1737 1738 struct hostkeys_update_ctx { 1739 /* The hostname and (optionally) IP address string for the server */ 1740 char *host_str, *ip_str; 1741 1742 /* 1743 * Keys received from the server and a flag for each indicating 1744 * whether they already exist in known_hosts. 1745 * keys_seen is filled in by hostkeys_find() and later (for new 1746 * keys) by client_global_hostkeys_private_confirm(). 1747 */ 1748 struct sshkey **keys; 1749 int *keys_seen; 1750 size_t nkeys, nnew; 1751 1752 /* 1753 * Keys that are in known_hosts, but were not present in the update 1754 * from the server (i.e. scheduled to be deleted). 1755 * Filled in by hostkeys_find(). 1756 */ 1757 struct sshkey **old_keys; 1758 size_t nold; 1759 }; 1760 1761 static void 1762 hostkeys_update_ctx_free(struct hostkeys_update_ctx *ctx) 1763 { 1764 size_t i; 1765 1766 if (ctx == NULL) 1767 return; 1768 for (i = 0; i < ctx->nkeys; i++) 1769 sshkey_free(ctx->keys[i]); 1770 free(ctx->keys); 1771 free(ctx->keys_seen); 1772 for (i = 0; i < ctx->nold; i++) 1773 sshkey_free(ctx->old_keys[i]); 1774 free(ctx->old_keys); 1775 free(ctx->host_str); 1776 free(ctx->ip_str); 1777 free(ctx); 1778 } 1779 1780 static int 1781 hostkeys_find(struct hostkey_foreach_line *l, void *_ctx) 1782 { 1783 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 1784 size_t i; 1785 struct sshkey **tmp; 1786 1787 if (l->status != HKF_STATUS_MATCHED || l->key == NULL) 1788 return 0; 1789 1790 /* Mark off keys we've already seen for this host */ 1791 for (i = 0; i < ctx->nkeys; i++) { 1792 if (sshkey_equal(l->key, ctx->keys[i])) { 1793 debug3("%s: found %s key at %s:%ld", __func__, 1794 sshkey_ssh_name(ctx->keys[i]), l->path, l->linenum); 1795 ctx->keys_seen[i] = 1; 1796 return 0; 1797 } 1798 } 1799 /* This line contained a key that not offered by the server */ 1800 debug3("%s: deprecated %s key at %s:%ld", __func__, 1801 sshkey_ssh_name(l->key), l->path, l->linenum); 1802 if ((tmp = recallocarray(ctx->old_keys, ctx->nold, ctx->nold + 1, 1803 sizeof(*ctx->old_keys))) == NULL) 1804 fatal("%s: recallocarray failed nold = %zu", 1805 __func__, ctx->nold); 1806 ctx->old_keys = tmp; 1807 ctx->old_keys[ctx->nold++] = l->key; 1808 l->key = NULL; 1809 1810 return 0; 1811 } 1812 1813 static void 1814 update_known_hosts(struct hostkeys_update_ctx *ctx) 1815 { 1816 int r, was_raw = 0; 1817 int loglevel = options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK ? 1818 SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_VERBOSE; 1819 char *fp, *response; 1820 size_t i; 1821 1822 for (i = 0; i < ctx->nkeys; i++) { 1823 if (ctx->keys_seen[i] != 2) 1824 continue; 1825 if ((fp = sshkey_fingerprint(ctx->keys[i], 1826 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 1827 fatal("%s: sshkey_fingerprint failed", __func__); 1828 do_log2(loglevel, "Learned new hostkey: %s %s", 1829 sshkey_type(ctx->keys[i]), fp); 1830 free(fp); 1831 } 1832 for (i = 0; i < ctx->nold; i++) { 1833 if ((fp = sshkey_fingerprint(ctx->old_keys[i], 1834 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 1835 fatal("%s: sshkey_fingerprint failed", __func__); 1836 do_log2(loglevel, "Deprecating obsolete hostkey: %s %s", 1837 sshkey_type(ctx->old_keys[i]), fp); 1838 free(fp); 1839 } 1840 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) { 1841 if (get_saved_tio() != NULL) { 1842 leave_raw_mode(1); 1843 was_raw = 1; 1844 } 1845 response = NULL; 1846 for (i = 0; !quit_pending && i < 3; i++) { 1847 free(response); 1848 response = read_passphrase("Accept updated hostkeys? " 1849 "(yes/no): ", RP_ECHO); 1850 if (strcasecmp(response, "yes") == 0) 1851 break; 1852 else if (quit_pending || response == NULL || 1853 strcasecmp(response, "no") == 0) { 1854 options.update_hostkeys = 0; 1855 break; 1856 } else { 1857 do_log2(loglevel, "Please enter " 1858 "\"yes\" or \"no\""); 1859 } 1860 } 1861 if (quit_pending || i >= 3 || response == NULL) 1862 options.update_hostkeys = 0; 1863 free(response); 1864 if (was_raw) 1865 enter_raw_mode(1); 1866 } 1867 1868 /* 1869 * Now that all the keys are verified, we can go ahead and replace 1870 * them in known_hosts (assuming SSH_UPDATE_HOSTKEYS_ASK didn't 1871 * cancel the operation). 1872 */ 1873 if (options.update_hostkeys != 0 && 1874 (r = hostfile_replace_entries(options.user_hostfiles[0], 1875 ctx->host_str, ctx->ip_str, ctx->keys, ctx->nkeys, 1876 options.hash_known_hosts, 0, 1877 options.fingerprint_hash)) != 0) 1878 error("%s: hostfile_replace_entries failed: %s", 1879 __func__, ssh_err(r)); 1880 } 1881 1882 static void 1883 client_global_hostkeys_private_confirm(int type, u_int32_t seq, void *_ctx) 1884 { 1885 struct ssh *ssh = active_state; /* XXX */ 1886 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 1887 size_t i, ndone; 1888 struct sshbuf *signdata; 1889 int r; 1890 const u_char *sig; 1891 size_t siglen; 1892 1893 if (ctx->nnew == 0) 1894 fatal("%s: ctx->nnew == 0", __func__); /* sanity */ 1895 if (type != SSH2_MSG_REQUEST_SUCCESS) { 1896 error("Server failed to confirm ownership of " 1897 "private host keys"); 1898 hostkeys_update_ctx_free(ctx); 1899 return; 1900 } 1901 if ((signdata = sshbuf_new()) == NULL) 1902 fatal("%s: sshbuf_new failed", __func__); 1903 /* Don't want to accidentally accept an unbound signature */ 1904 if (ssh->kex->session_id_len == 0) 1905 fatal("%s: ssh->kex->session_id_len == 0", __func__); 1906 /* 1907 * Expect a signature for each of the ctx->nnew private keys we 1908 * haven't seen before. They will be in the same order as the 1909 * ctx->keys where the corresponding ctx->keys_seen[i] == 0. 1910 */ 1911 for (ndone = i = 0; i < ctx->nkeys; i++) { 1912 if (ctx->keys_seen[i]) 1913 continue; 1914 /* Prepare data to be signed: session ID, unique string, key */ 1915 sshbuf_reset(signdata); 1916 if ( (r = sshbuf_put_cstring(signdata, 1917 "hostkeys-prove-00@openssh.com")) != 0 || 1918 (r = sshbuf_put_string(signdata, ssh->kex->session_id, 1919 ssh->kex->session_id_len)) != 0 || 1920 (r = sshkey_puts(ctx->keys[i], signdata)) != 0) 1921 fatal("%s: failed to prepare signature: %s", 1922 __func__, ssh_err(r)); 1923 /* Extract and verify signature */ 1924 if ((r = sshpkt_get_string_direct(ssh, &sig, &siglen)) != 0) { 1925 error("%s: couldn't parse message: %s", 1926 __func__, ssh_err(r)); 1927 goto out; 1928 } 1929 if ((r = sshkey_verify(ctx->keys[i], sig, siglen, 1930 sshbuf_ptr(signdata), sshbuf_len(signdata), 0)) != 0) { 1931 error("%s: server gave bad signature for %s key %zu", 1932 __func__, sshkey_type(ctx->keys[i]), i); 1933 goto out; 1934 } 1935 /* Key is good. Mark it as 'seen' */ 1936 ctx->keys_seen[i] = 2; 1937 ndone++; 1938 } 1939 if (ndone != ctx->nnew) 1940 fatal("%s: ndone != ctx->nnew (%zu / %zu)", __func__, 1941 ndone, ctx->nnew); /* Shouldn't happen */ 1942 ssh_packet_check_eom(ssh); 1943 1944 /* Make the edits to known_hosts */ 1945 update_known_hosts(ctx); 1946 out: 1947 hostkeys_update_ctx_free(ctx); 1948 } 1949 1950 /* 1951 * Returns non-zero if the key is accepted by HostkeyAlgorithms. 1952 * Made slightly less trivial by the multiple RSA signature algorithm names. 1953 */ 1954 static int 1955 key_accepted_by_hostkeyalgs(const struct sshkey *key) 1956 { 1957 const char *ktype = sshkey_ssh_name(key); 1958 const char *hostkeyalgs = options.hostkeyalgorithms != NULL ? 1959 options.hostkeyalgorithms : KEX_DEFAULT_PK_ALG; 1960 1961 if (key == NULL || key->type == KEY_UNSPEC) 1962 return 0; 1963 if (key->type == KEY_RSA && 1964 (match_pattern_list("rsa-sha2-256", hostkeyalgs, 0) == 1 || 1965 match_pattern_list("rsa-sha2-512", hostkeyalgs, 0) == 1)) 1966 return 1; 1967 return match_pattern_list(ktype, hostkeyalgs, 0) == 1; 1968 } 1969 1970 /* 1971 * Handle hostkeys-00@openssh.com global request to inform the client of all 1972 * the server's hostkeys. The keys are checked against the user's 1973 * HostkeyAlgorithms preference before they are accepted. 1974 */ 1975 static int 1976 client_input_hostkeys(void) 1977 { 1978 struct ssh *ssh = active_state; /* XXX */ 1979 const u_char *blob = NULL; 1980 size_t i, len = 0; 1981 struct sshbuf *buf = NULL; 1982 struct sshkey *key = NULL, **tmp; 1983 int r; 1984 char *fp; 1985 static int hostkeys_seen = 0; /* XXX use struct ssh */ 1986 extern struct sockaddr_storage hostaddr; /* XXX from ssh.c */ 1987 struct hostkeys_update_ctx *ctx = NULL; 1988 1989 if (hostkeys_seen) 1990 fatal("%s: server already sent hostkeys", __func__); 1991 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK && 1992 options.batch_mode) 1993 return 1; /* won't ask in batchmode, so don't even try */ 1994 if (!options.update_hostkeys || options.num_user_hostfiles <= 0) 1995 return 1; 1996 1997 ctx = xcalloc(1, sizeof(*ctx)); 1998 while (ssh_packet_remaining(ssh) > 0) { 1999 sshkey_free(key); 2000 key = NULL; 2001 if ((r = sshpkt_get_string_direct(ssh, &blob, &len)) != 0) { 2002 error("%s: couldn't parse message: %s", 2003 __func__, ssh_err(r)); 2004 goto out; 2005 } 2006 if ((r = sshkey_from_blob(blob, len, &key)) != 0) { 2007 error("%s: parse key: %s", __func__, ssh_err(r)); 2008 goto out; 2009 } 2010 fp = sshkey_fingerprint(key, options.fingerprint_hash, 2011 SSH_FP_DEFAULT); 2012 debug3("%s: received %s key %s", __func__, 2013 sshkey_type(key), fp); 2014 free(fp); 2015 2016 if (!key_accepted_by_hostkeyalgs(key)) { 2017 debug3("%s: %s key not permitted by HostkeyAlgorithms", 2018 __func__, sshkey_ssh_name(key)); 2019 continue; 2020 } 2021 /* Skip certs */ 2022 if (sshkey_is_cert(key)) { 2023 debug3("%s: %s key is a certificate; skipping", 2024 __func__, sshkey_ssh_name(key)); 2025 continue; 2026 } 2027 /* Ensure keys are unique */ 2028 for (i = 0; i < ctx->nkeys; i++) { 2029 if (sshkey_equal(key, ctx->keys[i])) { 2030 error("%s: received duplicated %s host key", 2031 __func__, sshkey_ssh_name(key)); 2032 goto out; 2033 } 2034 } 2035 /* Key is good, record it */ 2036 if ((tmp = recallocarray(ctx->keys, ctx->nkeys, ctx->nkeys + 1, 2037 sizeof(*ctx->keys))) == NULL) 2038 fatal("%s: recallocarray failed nkeys = %zu", 2039 __func__, ctx->nkeys); 2040 ctx->keys = tmp; 2041 ctx->keys[ctx->nkeys++] = key; 2042 key = NULL; 2043 } 2044 2045 if (ctx->nkeys == 0) { 2046 debug("%s: server sent no hostkeys", __func__); 2047 goto out; 2048 } 2049 2050 if ((ctx->keys_seen = calloc(ctx->nkeys, 2051 sizeof(*ctx->keys_seen))) == NULL) 2052 fatal("%s: calloc failed", __func__); 2053 2054 get_hostfile_hostname_ipaddr(host, 2055 options.check_host_ip ? (struct sockaddr *)&hostaddr : NULL, 2056 options.port, &ctx->host_str, 2057 options.check_host_ip ? &ctx->ip_str : NULL); 2058 2059 /* Find which keys we already know about. */ 2060 if ((r = hostkeys_foreach(options.user_hostfiles[0], hostkeys_find, 2061 ctx, ctx->host_str, ctx->ip_str, 2062 HKF_WANT_PARSE_KEY|HKF_WANT_MATCH)) != 0) { 2063 error("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r)); 2064 goto out; 2065 } 2066 2067 /* Figure out if we have any new keys to add */ 2068 ctx->nnew = 0; 2069 for (i = 0; i < ctx->nkeys; i++) { 2070 if (!ctx->keys_seen[i]) 2071 ctx->nnew++; 2072 } 2073 2074 debug3("%s: %zu keys from server: %zu new, %zu retained. %zu to remove", 2075 __func__, ctx->nkeys, ctx->nnew, ctx->nkeys - ctx->nnew, ctx->nold); 2076 2077 if (ctx->nnew == 0 && ctx->nold != 0) { 2078 /* We have some keys to remove. Just do it. */ 2079 update_known_hosts(ctx); 2080 } else if (ctx->nnew != 0) { 2081 /* 2082 * We have received hitherto-unseen keys from the server. 2083 * Ask the server to confirm ownership of the private halves. 2084 */ 2085 debug3("%s: asking server to prove ownership for %zu keys", 2086 __func__, ctx->nnew); 2087 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 2088 (r = sshpkt_put_cstring(ssh, 2089 "hostkeys-prove-00@openssh.com")) != 0 || 2090 (r = sshpkt_put_u8(ssh, 1)) != 0) /* bool: want reply */ 2091 fatal("%s: cannot prepare packet: %s", 2092 __func__, ssh_err(r)); 2093 if ((buf = sshbuf_new()) == NULL) 2094 fatal("%s: sshbuf_new", __func__); 2095 for (i = 0; i < ctx->nkeys; i++) { 2096 if (ctx->keys_seen[i]) 2097 continue; 2098 sshbuf_reset(buf); 2099 if ((r = sshkey_putb(ctx->keys[i], buf)) != 0) 2100 fatal("%s: sshkey_putb: %s", 2101 __func__, ssh_err(r)); 2102 if ((r = sshpkt_put_stringb(ssh, buf)) != 0) 2103 fatal("%s: sshpkt_put_string: %s", 2104 __func__, ssh_err(r)); 2105 } 2106 if ((r = sshpkt_send(ssh)) != 0) 2107 fatal("%s: sshpkt_send: %s", __func__, ssh_err(r)); 2108 client_register_global_confirm( 2109 client_global_hostkeys_private_confirm, ctx); 2110 ctx = NULL; /* will be freed in callback */ 2111 } 2112 2113 /* Success */ 2114 out: 2115 hostkeys_update_ctx_free(ctx); 2116 sshkey_free(key); 2117 sshbuf_free(buf); 2118 /* 2119 * NB. Return success for all cases. The server doesn't need to know 2120 * what the client does with its hosts file. 2121 */ 2122 return 1; 2123 } 2124 2125 static int 2126 client_input_global_request(int type, u_int32_t seq, struct ssh *ssh) 2127 { 2128 char *rtype; 2129 int want_reply; 2130 int success = 0; 2131 2132 rtype = packet_get_cstring(NULL); 2133 want_reply = packet_get_char(); 2134 debug("client_input_global_request: rtype %s want_reply %d", 2135 rtype, want_reply); 2136 if (strcmp(rtype, "hostkeys-00@openssh.com") == 0) 2137 success = client_input_hostkeys(); 2138 if (want_reply) { 2139 packet_start(success ? 2140 SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE); 2141 packet_send(); 2142 packet_write_wait(); 2143 } 2144 free(rtype); 2145 return 0; 2146 } 2147 2148 void 2149 client_session2_setup(int id, int want_tty, int want_subsystem, 2150 const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env) 2151 { 2152 int len; 2153 Channel *c = NULL; 2154 2155 debug2("%s: id %d", __func__, id); 2156 2157 if ((c = channel_lookup(id)) == NULL) 2158 fatal("client_session2_setup: channel %d: unknown channel", id); 2159 2160 packet_set_interactive(want_tty, 2161 options.ip_qos_interactive, options.ip_qos_bulk); 2162 2163 if (want_tty) { 2164 struct winsize ws; 2165 2166 /* Store window size in the packet. */ 2167 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0) 2168 memset(&ws, 0, sizeof(ws)); 2169 2170 channel_request_start(id, "pty-req", 1); 2171 client_expect_confirm(id, "PTY allocation", CONFIRM_TTY); 2172 packet_put_cstring(term != NULL ? term : ""); 2173 packet_put_int((u_int)ws.ws_col); 2174 packet_put_int((u_int)ws.ws_row); 2175 packet_put_int((u_int)ws.ws_xpixel); 2176 packet_put_int((u_int)ws.ws_ypixel); 2177 if (tiop == NULL) 2178 tiop = get_saved_tio(); 2179 tty_make_modes(-1, tiop); 2180 packet_send(); 2181 /* XXX wait for reply */ 2182 c->client_tty = 1; 2183 } 2184 2185 /* Transfer any environment variables from client to server */ 2186 if (options.num_send_env != 0 && env != NULL) { 2187 int i, j, matched; 2188 char *name, *val; 2189 2190 debug("Sending environment."); 2191 for (i = 0; env[i] != NULL; i++) { 2192 /* Split */ 2193 name = xstrdup(env[i]); 2194 if ((val = strchr(name, '=')) == NULL) { 2195 free(name); 2196 continue; 2197 } 2198 *val++ = '\0'; 2199 2200 matched = 0; 2201 for (j = 0; j < options.num_send_env; j++) { 2202 if (match_pattern(name, options.send_env[j])) { 2203 matched = 1; 2204 break; 2205 } 2206 } 2207 if (!matched) { 2208 debug3("Ignored env %s", name); 2209 free(name); 2210 continue; 2211 } 2212 2213 debug("Sending env %s = %s", name, val); 2214 channel_request_start(id, "env", 0); 2215 packet_put_cstring(name); 2216 packet_put_cstring(val); 2217 packet_send(); 2218 free(name); 2219 } 2220 } 2221 2222 len = buffer_len(cmd); 2223 if (len > 0) { 2224 if (len > 900) 2225 len = 900; 2226 if (want_subsystem) { 2227 debug("Sending subsystem: %.*s", 2228 len, (u_char*)buffer_ptr(cmd)); 2229 channel_request_start(id, "subsystem", 1); 2230 client_expect_confirm(id, "subsystem", CONFIRM_CLOSE); 2231 } else { 2232 debug("Sending command: %.*s", 2233 len, (u_char*)buffer_ptr(cmd)); 2234 channel_request_start(id, "exec", 1); 2235 client_expect_confirm(id, "exec", CONFIRM_CLOSE); 2236 } 2237 packet_put_string(buffer_ptr(cmd), buffer_len(cmd)); 2238 packet_send(); 2239 } else { 2240 channel_request_start(id, "shell", 1); 2241 client_expect_confirm(id, "shell", CONFIRM_CLOSE); 2242 packet_send(); 2243 } 2244 } 2245 2246 static void 2247 client_init_dispatch(void) 2248 { 2249 dispatch_init(&dispatch_protocol_error); 2250 2251 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); 2252 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); 2253 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); 2254 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); 2255 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open); 2256 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 2257 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 2258 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req); 2259 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); 2260 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm); 2261 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm); 2262 dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request); 2263 2264 /* rekeying */ 2265 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); 2266 2267 /* global request reply messages */ 2268 dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply); 2269 dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply); 2270 } 2271 2272 void 2273 client_stop_mux(void) 2274 { 2275 if (options.control_path != NULL && muxserver_sock != -1) 2276 unlink(options.control_path); 2277 /* 2278 * If we are in persist mode, or don't have a shell, signal that we 2279 * should close when all active channels are closed. 2280 */ 2281 if (options.control_persist || no_shell_flag) { 2282 session_closed = 1; 2283 setproctitle("[stopped mux]"); 2284 } 2285 } 2286 2287 /* client specific fatal cleanup */ 2288 void 2289 cleanup_exit(int i) 2290 { 2291 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 2292 leave_non_blocking(); 2293 if (options.control_path != NULL && muxserver_sock != -1) 2294 unlink(options.control_path); 2295 ssh_kill_proxy_command(); 2296 _exit(i); 2297 } 2298