1 /* $OpenBSD: clientloop.c,v 1.312 2018/04/10 00:10:49 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 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 /* XXX move to struct ssh? */ 173 struct global_confirm { 174 TAILQ_ENTRY(global_confirm) entry; 175 global_confirm_cb *cb; 176 void *ctx; 177 int ref_count; 178 }; 179 TAILQ_HEAD(global_confirms, global_confirm); 180 static struct global_confirms global_confirms = 181 TAILQ_HEAD_INITIALIZER(global_confirms); 182 183 void ssh_process_session2_setup(int, int, int, Buffer *); 184 185 /* Restores stdin to blocking mode. */ 186 187 static void 188 leave_non_blocking(void) 189 { 190 if (in_non_blocking_mode) { 191 unset_nonblock(fileno(stdin)); 192 in_non_blocking_mode = 0; 193 } 194 } 195 196 /* 197 * Signal handler for the window change signal (SIGWINCH). This just sets a 198 * flag indicating that the window has changed. 199 */ 200 /*ARGSUSED */ 201 static void 202 window_change_handler(int sig) 203 { 204 received_window_change_signal = 1; 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 * Sets control_persist_exit_time to the absolute time when the 221 * backgrounded control master should exit due to expiry of the 222 * ControlPersist timeout. Sets it to 0 if we are not a backgrounded 223 * control master process, or if there is no ControlPersist timeout. 224 */ 225 static void 226 set_control_persist_exit_time(struct ssh *ssh) 227 { 228 if (muxserver_sock == -1 || !options.control_persist 229 || options.control_persist_timeout == 0) { 230 /* not using a ControlPersist timeout */ 231 control_persist_exit_time = 0; 232 } else if (channel_still_open(ssh)) { 233 /* some client connections are still open */ 234 if (control_persist_exit_time > 0) 235 debug2("%s: cancel scheduled exit", __func__); 236 control_persist_exit_time = 0; 237 } else if (control_persist_exit_time <= 0) { 238 /* a client connection has recently closed */ 239 control_persist_exit_time = monotime() + 240 (time_t)options.control_persist_timeout; 241 debug2("%s: schedule exit in %d seconds", __func__, 242 options.control_persist_timeout); 243 } 244 /* else we are already counting down to the timeout */ 245 } 246 247 #define SSH_X11_VALID_DISPLAY_CHARS ":/.-_" 248 static int 249 client_x11_display_valid(const char *display) 250 { 251 size_t i, dlen; 252 253 if (display == NULL) 254 return 0; 255 256 dlen = strlen(display); 257 for (i = 0; i < dlen; i++) { 258 if (!isalnum((u_char)display[i]) && 259 strchr(SSH_X11_VALID_DISPLAY_CHARS, display[i]) == NULL) { 260 debug("Invalid character '%c' in DISPLAY", display[i]); 261 return 0; 262 } 263 } 264 return 1; 265 } 266 267 #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1" 268 #define X11_TIMEOUT_SLACK 60 269 int 270 client_x11_get_proto(struct ssh *ssh, const char *display, 271 const char *xauth_path, u_int trusted, u_int timeout, 272 char **_proto, char **_data) 273 { 274 char cmd[1024], line[512], xdisplay[512]; 275 char xauthfile[PATH_MAX], xauthdir[PATH_MAX]; 276 static char proto[512], data[512]; 277 FILE *f; 278 int got_data = 0, generated = 0, do_unlink = 0, r; 279 struct stat st; 280 u_int now, x11_timeout_real; 281 282 *_proto = proto; 283 *_data = data; 284 proto[0] = data[0] = xauthfile[0] = xauthdir[0] = '\0'; 285 286 if (!client_x11_display_valid(display)) { 287 if (display != NULL) 288 logit("DISPLAY \"%s\" invalid; disabling X11 forwarding", 289 display); 290 return -1; 291 } 292 if (xauth_path != NULL && stat(xauth_path, &st) == -1) { 293 debug("No xauth program."); 294 xauth_path = NULL; 295 } 296 297 if (xauth_path != NULL) { 298 /* 299 * Handle FamilyLocal case where $DISPLAY does 300 * not match an authorization entry. For this we 301 * just try "xauth list unix:displaynum.screennum". 302 * XXX: "localhost" match to determine FamilyLocal 303 * is not perfect. 304 */ 305 if (strncmp(display, "localhost:", 10) == 0) { 306 if ((r = snprintf(xdisplay, sizeof(xdisplay), "unix:%s", 307 display + 10)) < 0 || 308 (size_t)r >= sizeof(xdisplay)) { 309 error("%s: display name too long", __func__); 310 return -1; 311 } 312 display = xdisplay; 313 } 314 if (trusted == 0) { 315 /* 316 * Generate an untrusted X11 auth cookie. 317 * 318 * The authentication cookie should briefly outlive 319 * ssh's willingness to forward X11 connections to 320 * avoid nasty fail-open behaviour in the X server. 321 */ 322 mktemp_proto(xauthdir, sizeof(xauthdir)); 323 if (mkdtemp(xauthdir) == NULL) { 324 error("%s: mkdtemp: %s", 325 __func__, strerror(errno)); 326 return -1; 327 } 328 do_unlink = 1; 329 if ((r = snprintf(xauthfile, sizeof(xauthfile), 330 "%s/xauthfile", xauthdir)) < 0 || 331 (size_t)r >= sizeof(xauthfile)) { 332 error("%s: xauthfile path too long", __func__); 333 unlink(xauthfile); 334 rmdir(xauthdir); 335 return -1; 336 } 337 338 if (timeout >= UINT_MAX - X11_TIMEOUT_SLACK) 339 x11_timeout_real = UINT_MAX; 340 else 341 x11_timeout_real = timeout + X11_TIMEOUT_SLACK; 342 if ((r = snprintf(cmd, sizeof(cmd), 343 "%s -f %s generate %s " SSH_X11_PROTO 344 " untrusted timeout %u 2>" _PATH_DEVNULL, 345 xauth_path, xauthfile, display, 346 x11_timeout_real)) < 0 || 347 (size_t)r >= sizeof(cmd)) 348 fatal("%s: cmd too long", __func__); 349 debug2("%s: %s", __func__, cmd); 350 if (x11_refuse_time == 0) { 351 now = monotime() + 1; 352 if (UINT_MAX - timeout < now) 353 x11_refuse_time = UINT_MAX; 354 else 355 x11_refuse_time = now + timeout; 356 channel_set_x11_refuse_time(ssh, 357 x11_refuse_time); 358 } 359 if (system(cmd) == 0) 360 generated = 1; 361 } 362 363 /* 364 * When in untrusted mode, we read the cookie only if it was 365 * successfully generated as an untrusted one in the step 366 * above. 367 */ 368 if (trusted || generated) { 369 snprintf(cmd, sizeof(cmd), 370 "%s %s%s list %s 2>" _PATH_DEVNULL, 371 xauth_path, 372 generated ? "-f " : "" , 373 generated ? xauthfile : "", 374 display); 375 debug2("x11_get_proto: %s", cmd); 376 f = popen(cmd, "r"); 377 if (f && fgets(line, sizeof(line), f) && 378 sscanf(line, "%*s %511s %511s", proto, data) == 2) 379 got_data = 1; 380 if (f) 381 pclose(f); 382 } 383 } 384 385 if (do_unlink) { 386 unlink(xauthfile); 387 rmdir(xauthdir); 388 } 389 390 /* Don't fall back to fake X11 data for untrusted forwarding */ 391 if (!trusted && !got_data) { 392 error("Warning: untrusted X11 forwarding setup failed: " 393 "xauth key data not generated"); 394 return -1; 395 } 396 397 /* 398 * If we didn't get authentication data, just make up some 399 * data. The forwarding code will check the validity of the 400 * response anyway, and substitute this data. The X11 401 * server, however, will ignore this fake data and use 402 * whatever authentication mechanisms it was using otherwise 403 * for the local connection. 404 */ 405 if (!got_data) { 406 u_int8_t rnd[16]; 407 u_int i; 408 409 logit("Warning: No xauth data; " 410 "using fake authentication data for X11 forwarding."); 411 strlcpy(proto, SSH_X11_PROTO, sizeof proto); 412 arc4random_buf(rnd, sizeof(rnd)); 413 for (i = 0; i < sizeof(rnd); i++) { 414 snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", 415 rnd[i]); 416 } 417 } 418 419 return 0; 420 } 421 422 /* 423 * Checks if the client window has changed, and sends a packet about it to 424 * the server if so. The actual change is detected elsewhere (by a software 425 * interrupt on Unix); this just checks the flag and sends a message if 426 * appropriate. 427 */ 428 429 static void 430 client_check_window_change(struct ssh *ssh) 431 { 432 if (!received_window_change_signal) 433 return; 434 /** XXX race */ 435 received_window_change_signal = 0; 436 437 debug2("%s: changed", __func__); 438 439 channel_send_window_changes(ssh); 440 } 441 442 static int 443 client_global_request_reply(int type, u_int32_t seq, struct ssh *ssh) 444 { 445 struct global_confirm *gc; 446 447 if ((gc = TAILQ_FIRST(&global_confirms)) == NULL) 448 return 0; 449 if (gc->cb != NULL) 450 gc->cb(ssh, type, seq, gc->ctx); 451 if (--gc->ref_count <= 0) { 452 TAILQ_REMOVE(&global_confirms, gc, entry); 453 explicit_bzero(gc, sizeof(*gc)); 454 free(gc); 455 } 456 457 packet_set_alive_timeouts(0); 458 return 0; 459 } 460 461 static void 462 server_alive_check(void) 463 { 464 if (packet_inc_alive_timeouts() > options.server_alive_count_max) { 465 logit("Timeout, server %s not responding.", host); 466 cleanup_exit(255); 467 } 468 packet_start(SSH2_MSG_GLOBAL_REQUEST); 469 packet_put_cstring("keepalive@openssh.com"); 470 packet_put_char(1); /* boolean: want reply */ 471 packet_send(); 472 /* Insert an empty placeholder to maintain ordering */ 473 client_register_global_confirm(NULL, NULL); 474 } 475 476 /* 477 * Waits until the client can do something (some data becomes available on 478 * one of the file descriptors). 479 */ 480 static void 481 client_wait_until_can_do_something(struct ssh *ssh, 482 fd_set **readsetp, fd_set **writesetp, 483 int *maxfdp, u_int *nallocp, int rekeying) 484 { 485 struct timeval tv, *tvp; 486 int timeout_secs; 487 time_t minwait_secs = 0, server_alive_time = 0, now = monotime(); 488 int ret; 489 490 /* Add any selections by the channel mechanism. */ 491 channel_prepare_select(active_state, readsetp, writesetp, maxfdp, 492 nallocp, &minwait_secs); 493 494 /* channel_prepare_select could have closed the last channel */ 495 if (session_closed && !channel_still_open(ssh) && 496 !packet_have_data_to_write()) { 497 /* clear mask since we did not call select() */ 498 memset(*readsetp, 0, *nallocp); 499 memset(*writesetp, 0, *nallocp); 500 return; 501 } 502 503 FD_SET(connection_in, *readsetp); 504 505 /* Select server connection if have data to write to the server. */ 506 if (packet_have_data_to_write()) 507 FD_SET(connection_out, *writesetp); 508 509 /* 510 * Wait for something to happen. This will suspend the process until 511 * some selected descriptor can be read, written, or has some other 512 * event pending, or a timeout expires. 513 */ 514 515 timeout_secs = INT_MAX; /* we use INT_MAX to mean no timeout */ 516 if (options.server_alive_interval > 0) { 517 timeout_secs = options.server_alive_interval; 518 server_alive_time = now + options.server_alive_interval; 519 } 520 if (options.rekey_interval > 0 && !rekeying) 521 timeout_secs = MINIMUM(timeout_secs, packet_get_rekey_timeout()); 522 set_control_persist_exit_time(ssh); 523 if (control_persist_exit_time > 0) { 524 timeout_secs = MINIMUM(timeout_secs, 525 control_persist_exit_time - now); 526 if (timeout_secs < 0) 527 timeout_secs = 0; 528 } 529 if (minwait_secs != 0) 530 timeout_secs = MINIMUM(timeout_secs, (int)minwait_secs); 531 if (timeout_secs == INT_MAX) 532 tvp = NULL; 533 else { 534 tv.tv_sec = timeout_secs; 535 tv.tv_usec = 0; 536 tvp = &tv; 537 } 538 539 ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp); 540 if (ret < 0) { 541 char buf[100]; 542 543 /* 544 * We have to clear the select masks, because we return. 545 * We have to return, because the mainloop checks for the flags 546 * set by the signal handlers. 547 */ 548 memset(*readsetp, 0, *nallocp); 549 memset(*writesetp, 0, *nallocp); 550 551 if (errno == EINTR) 552 return; 553 /* Note: we might still have data in the buffers. */ 554 snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno)); 555 buffer_append(&stderr_buffer, buf, strlen(buf)); 556 quit_pending = 1; 557 } else if (ret == 0) { 558 /* 559 * Timeout. Could have been either keepalive or rekeying. 560 * Keepalive we check here, rekeying is checked in clientloop. 561 */ 562 if (server_alive_time != 0 && server_alive_time <= monotime()) 563 server_alive_check(); 564 } 565 566 } 567 568 static void 569 client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr) 570 { 571 /* Flush stdout and stderr buffers. */ 572 if (buffer_len(bout) > 0) 573 atomicio(vwrite, fileno(stdout), buffer_ptr(bout), 574 buffer_len(bout)); 575 if (buffer_len(berr) > 0) 576 atomicio(vwrite, fileno(stderr), buffer_ptr(berr), 577 buffer_len(berr)); 578 579 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 580 581 sshbuf_reset(bin); 582 sshbuf_reset(bout); 583 sshbuf_reset(berr); 584 585 /* Send the suspend signal to the program itself. */ 586 kill(getpid(), SIGTSTP); 587 588 /* Reset window sizes in case they have changed */ 589 received_window_change_signal = 1; 590 591 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 592 } 593 594 static void 595 client_process_net_input(fd_set *readset) 596 { 597 int len; 598 char buf[8192]; 599 600 /* 601 * Read input from the server, and add any such data to the buffer of 602 * the packet subsystem. 603 */ 604 if (FD_ISSET(connection_in, readset)) { 605 /* Read as much as possible. */ 606 len = read(connection_in, buf, sizeof(buf)); 607 if (len == 0) { 608 /* 609 * Received EOF. The remote host has closed the 610 * connection. 611 */ 612 snprintf(buf, sizeof buf, 613 "Connection to %.300s closed by remote host.\r\n", 614 host); 615 buffer_append(&stderr_buffer, buf, strlen(buf)); 616 quit_pending = 1; 617 return; 618 } 619 /* 620 * There is a kernel bug on Solaris that causes select to 621 * sometimes wake up even though there is no data available. 622 */ 623 if (len < 0 && (errno == EAGAIN || errno == EINTR)) 624 len = 0; 625 626 if (len < 0) { 627 /* 628 * An error has encountered. Perhaps there is a 629 * network problem. 630 */ 631 snprintf(buf, sizeof buf, 632 "Read from remote host %.300s: %.100s\r\n", 633 host, strerror(errno)); 634 buffer_append(&stderr_buffer, buf, strlen(buf)); 635 quit_pending = 1; 636 return; 637 } 638 packet_process_incoming(buf, len); 639 } 640 } 641 642 static void 643 client_status_confirm(struct ssh *ssh, int type, Channel *c, void *ctx) 644 { 645 struct channel_reply_ctx *cr = (struct channel_reply_ctx *)ctx; 646 char errmsg[256]; 647 int tochan; 648 649 /* 650 * If a TTY was explicitly requested, then a failure to allocate 651 * one is fatal. 652 */ 653 if (cr->action == CONFIRM_TTY && 654 (options.request_tty == REQUEST_TTY_FORCE || 655 options.request_tty == REQUEST_TTY_YES)) 656 cr->action = CONFIRM_CLOSE; 657 658 /* XXX suppress on mux _client_ quietmode */ 659 tochan = options.log_level >= SYSLOG_LEVEL_ERROR && 660 c->ctl_chan != -1 && c->extended_usage == CHAN_EXTENDED_WRITE; 661 662 if (type == SSH2_MSG_CHANNEL_SUCCESS) { 663 debug2("%s request accepted on channel %d", 664 cr->request_type, c->self); 665 } else if (type == SSH2_MSG_CHANNEL_FAILURE) { 666 if (tochan) { 667 snprintf(errmsg, sizeof(errmsg), 668 "%s request failed\r\n", cr->request_type); 669 } else { 670 snprintf(errmsg, sizeof(errmsg), 671 "%s request failed on channel %d", 672 cr->request_type, c->self); 673 } 674 /* If error occurred on primary session channel, then exit */ 675 if (cr->action == CONFIRM_CLOSE && c->self == session_ident) 676 fatal("%s", errmsg); 677 /* 678 * If error occurred on mux client, append to 679 * their stderr. 680 */ 681 if (tochan) { 682 buffer_append(c->extended, errmsg, strlen(errmsg)); 683 } else 684 error("%s", errmsg); 685 if (cr->action == CONFIRM_TTY) { 686 /* 687 * If a TTY allocation error occurred, then arrange 688 * for the correct TTY to leave raw mode. 689 */ 690 if (c->self == session_ident) 691 leave_raw_mode(0); 692 else 693 mux_tty_alloc_failed(ssh, c); 694 } else if (cr->action == CONFIRM_CLOSE) { 695 chan_read_failed(ssh, c); 696 chan_write_failed(ssh, c); 697 } 698 } 699 free(cr); 700 } 701 702 static void 703 client_abandon_status_confirm(struct ssh *ssh, Channel *c, void *ctx) 704 { 705 free(ctx); 706 } 707 708 void 709 client_expect_confirm(struct ssh *ssh, int id, const char *request, 710 enum confirm_action action) 711 { 712 struct channel_reply_ctx *cr = xcalloc(1, sizeof(*cr)); 713 714 cr->request_type = request; 715 cr->action = action; 716 717 channel_register_status_confirm(ssh, id, client_status_confirm, 718 client_abandon_status_confirm, cr); 719 } 720 721 void 722 client_register_global_confirm(global_confirm_cb *cb, void *ctx) 723 { 724 struct global_confirm *gc, *last_gc; 725 726 /* Coalesce identical callbacks */ 727 last_gc = TAILQ_LAST(&global_confirms, global_confirms); 728 if (last_gc && last_gc->cb == cb && last_gc->ctx == ctx) { 729 if (++last_gc->ref_count >= INT_MAX) 730 fatal("%s: last_gc->ref_count = %d", 731 __func__, last_gc->ref_count); 732 return; 733 } 734 735 gc = xcalloc(1, sizeof(*gc)); 736 gc->cb = cb; 737 gc->ctx = ctx; 738 gc->ref_count = 1; 739 TAILQ_INSERT_TAIL(&global_confirms, gc, entry); 740 } 741 742 static void 743 process_cmdline(struct ssh *ssh) 744 { 745 void (*handler)(int); 746 char *s, *cmd; 747 int ok, delete = 0, local = 0, remote = 0, dynamic = 0; 748 struct Forward fwd; 749 750 memset(&fwd, 0, sizeof(fwd)); 751 752 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 753 handler = signal(SIGINT, SIG_IGN); 754 cmd = s = read_passphrase("\r\nssh> ", RP_ECHO); 755 if (s == NULL) 756 goto out; 757 while (isspace((u_char)*s)) 758 s++; 759 if (*s == '-') 760 s++; /* Skip cmdline '-', if any */ 761 if (*s == '\0') 762 goto out; 763 764 if (*s == 'h' || *s == 'H' || *s == '?') { 765 logit("Commands:"); 766 logit(" -L[bind_address:]port:host:hostport " 767 "Request local forward"); 768 logit(" -R[bind_address:]port:host:hostport " 769 "Request remote forward"); 770 logit(" -D[bind_address:]port " 771 "Request dynamic forward"); 772 logit(" -KL[bind_address:]port " 773 "Cancel local forward"); 774 logit(" -KR[bind_address:]port " 775 "Cancel remote forward"); 776 logit(" -KD[bind_address:]port " 777 "Cancel dynamic forward"); 778 if (!options.permit_local_command) 779 goto out; 780 logit(" !args " 781 "Execute local command"); 782 goto out; 783 } 784 785 if (*s == '!' && options.permit_local_command) { 786 s++; 787 ssh_local_cmd(s); 788 goto out; 789 } 790 791 if (*s == 'K') { 792 delete = 1; 793 s++; 794 } 795 if (*s == 'L') 796 local = 1; 797 else if (*s == 'R') 798 remote = 1; 799 else if (*s == 'D') 800 dynamic = 1; 801 else { 802 logit("Invalid command."); 803 goto out; 804 } 805 806 while (isspace((u_char)*++s)) 807 ; 808 809 /* XXX update list of forwards in options */ 810 if (delete) { 811 /* We pass 1 for dynamicfwd to restrict to 1 or 2 fields. */ 812 if (!parse_forward(&fwd, s, 1, 0)) { 813 logit("Bad forwarding close specification."); 814 goto out; 815 } 816 if (remote) 817 ok = channel_request_rforward_cancel(ssh, &fwd) == 0; 818 else if (dynamic) 819 ok = channel_cancel_lport_listener(ssh, &fwd, 820 0, &options.fwd_opts) > 0; 821 else 822 ok = channel_cancel_lport_listener(ssh, &fwd, 823 CHANNEL_CANCEL_PORT_STATIC, 824 &options.fwd_opts) > 0; 825 if (!ok) { 826 logit("Unknown port forwarding."); 827 goto out; 828 } 829 logit("Canceled forwarding."); 830 } else { 831 if (!parse_forward(&fwd, s, dynamic, remote)) { 832 logit("Bad forwarding specification."); 833 goto out; 834 } 835 if (local || dynamic) { 836 if (!channel_setup_local_fwd_listener(ssh, &fwd, 837 &options.fwd_opts)) { 838 logit("Port forwarding failed."); 839 goto out; 840 } 841 } else { 842 if (channel_request_remote_forwarding(ssh, &fwd) < 0) { 843 logit("Port forwarding failed."); 844 goto out; 845 } 846 } 847 logit("Forwarding port."); 848 } 849 850 out: 851 signal(SIGINT, handler); 852 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 853 free(cmd); 854 free(fwd.listen_host); 855 free(fwd.listen_path); 856 free(fwd.connect_host); 857 free(fwd.connect_path); 858 } 859 860 /* reasons to suppress output of an escape command in help output */ 861 #define SUPPRESS_NEVER 0 /* never suppress, always show */ 862 #define SUPPRESS_MUXCLIENT 1 /* don't show in mux client sessions */ 863 #define SUPPRESS_MUXMASTER 2 /* don't show in mux master sessions */ 864 #define SUPPRESS_SYSLOG 4 /* don't show when logging to syslog */ 865 struct escape_help_text { 866 const char *cmd; 867 const char *text; 868 unsigned int flags; 869 }; 870 static struct escape_help_text esc_txt[] = { 871 {".", "terminate session", SUPPRESS_MUXMASTER}, 872 {".", "terminate connection (and any multiplexed sessions)", 873 SUPPRESS_MUXCLIENT}, 874 {"B", "send a BREAK to the remote system", SUPPRESS_NEVER}, 875 {"C", "open a command line", SUPPRESS_MUXCLIENT}, 876 {"R", "request rekey", SUPPRESS_NEVER}, 877 {"V/v", "decrease/increase verbosity (LogLevel)", SUPPRESS_MUXCLIENT}, 878 {"^Z", "suspend ssh", SUPPRESS_MUXCLIENT}, 879 {"#", "list forwarded connections", SUPPRESS_NEVER}, 880 {"&", "background ssh (when waiting for connections to terminate)", 881 SUPPRESS_MUXCLIENT}, 882 {"?", "this message", SUPPRESS_NEVER}, 883 }; 884 885 static void 886 print_escape_help(Buffer *b, int escape_char, int mux_client, int using_stderr) 887 { 888 unsigned int i, suppress_flags; 889 char string[1024]; 890 891 snprintf(string, sizeof string, "%c?\r\n" 892 "Supported escape sequences:\r\n", escape_char); 893 buffer_append(b, string, strlen(string)); 894 895 suppress_flags = 896 (mux_client ? SUPPRESS_MUXCLIENT : 0) | 897 (mux_client ? 0 : SUPPRESS_MUXMASTER) | 898 (using_stderr ? 0 : SUPPRESS_SYSLOG); 899 900 for (i = 0; i < sizeof(esc_txt)/sizeof(esc_txt[0]); i++) { 901 if (esc_txt[i].flags & suppress_flags) 902 continue; 903 snprintf(string, sizeof string, " %c%-3s - %s\r\n", 904 escape_char, esc_txt[i].cmd, esc_txt[i].text); 905 buffer_append(b, string, strlen(string)); 906 } 907 908 snprintf(string, sizeof string, 909 " %c%c - send the escape character by typing it twice\r\n" 910 "(Note that escapes are only recognized immediately after " 911 "newline.)\r\n", escape_char, escape_char); 912 buffer_append(b, string, strlen(string)); 913 } 914 915 /* 916 * Process the characters one by one. 917 */ 918 static int 919 process_escapes(struct ssh *ssh, Channel *c, 920 Buffer *bin, Buffer *bout, Buffer *berr, 921 char *buf, int len) 922 { 923 char string[1024]; 924 pid_t pid; 925 int bytes = 0; 926 u_int i; 927 u_char ch; 928 char *s; 929 struct escape_filter_ctx *efc = c->filter_ctx == NULL ? 930 NULL : (struct escape_filter_ctx *)c->filter_ctx; 931 932 if (c->filter_ctx == NULL) 933 return 0; 934 935 if (len <= 0) 936 return (0); 937 938 for (i = 0; i < (u_int)len; i++) { 939 /* Get one character at a time. */ 940 ch = buf[i]; 941 942 if (efc->escape_pending) { 943 /* We have previously seen an escape character. */ 944 /* Clear the flag now. */ 945 efc->escape_pending = 0; 946 947 /* Process the escaped character. */ 948 switch (ch) { 949 case '.': 950 /* Terminate the connection. */ 951 snprintf(string, sizeof string, "%c.\r\n", 952 efc->escape_char); 953 buffer_append(berr, string, strlen(string)); 954 955 if (c && c->ctl_chan != -1) { 956 chan_read_failed(ssh, c); 957 chan_write_failed(ssh, c); 958 if (c->detach_user) { 959 c->detach_user(ssh, 960 c->self, NULL); 961 } 962 c->type = SSH_CHANNEL_ABANDONED; 963 buffer_clear(c->input); 964 chan_ibuf_empty(ssh, c); 965 return 0; 966 } else 967 quit_pending = 1; 968 return -1; 969 970 case 'Z' - 64: 971 /* XXX support this for mux clients */ 972 if (c && c->ctl_chan != -1) { 973 char b[16]; 974 noescape: 975 if (ch == 'Z' - 64) 976 snprintf(b, sizeof b, "^Z"); 977 else 978 snprintf(b, sizeof b, "%c", ch); 979 snprintf(string, sizeof string, 980 "%c%s escape not available to " 981 "multiplexed sessions\r\n", 982 efc->escape_char, b); 983 buffer_append(berr, string, 984 strlen(string)); 985 continue; 986 } 987 /* Suspend the program. Inform the user */ 988 snprintf(string, sizeof string, 989 "%c^Z [suspend ssh]\r\n", efc->escape_char); 990 buffer_append(berr, string, strlen(string)); 991 992 /* Restore terminal modes and suspend. */ 993 client_suspend_self(bin, bout, berr); 994 995 /* We have been continued. */ 996 continue; 997 998 case 'B': 999 snprintf(string, sizeof string, 1000 "%cB\r\n", efc->escape_char); 1001 buffer_append(berr, string, strlen(string)); 1002 channel_request_start(ssh, c->self, "break", 0); 1003 packet_put_int(1000); 1004 packet_send(); 1005 continue; 1006 1007 case 'R': 1008 if (datafellows & SSH_BUG_NOREKEY) 1009 logit("Server does not " 1010 "support re-keying"); 1011 else 1012 need_rekeying = 1; 1013 continue; 1014 1015 case 'V': 1016 /* FALLTHROUGH */ 1017 case 'v': 1018 if (c && c->ctl_chan != -1) 1019 goto noescape; 1020 if (!log_is_on_stderr()) { 1021 snprintf(string, sizeof string, 1022 "%c%c [Logging to syslog]\r\n", 1023 efc->escape_char, ch); 1024 buffer_append(berr, string, 1025 strlen(string)); 1026 continue; 1027 } 1028 if (ch == 'V' && options.log_level > 1029 SYSLOG_LEVEL_QUIET) 1030 log_change_level(--options.log_level); 1031 if (ch == 'v' && options.log_level < 1032 SYSLOG_LEVEL_DEBUG3) 1033 log_change_level(++options.log_level); 1034 snprintf(string, sizeof string, 1035 "%c%c [LogLevel %s]\r\n", 1036 efc->escape_char, ch, 1037 log_level_name(options.log_level)); 1038 buffer_append(berr, string, strlen(string)); 1039 continue; 1040 1041 case '&': 1042 if (c && c->ctl_chan != -1) 1043 goto noescape; 1044 /* 1045 * Detach the program (continue to serve 1046 * connections, but put in background and no 1047 * more new connections). 1048 */ 1049 /* Restore tty modes. */ 1050 leave_raw_mode( 1051 options.request_tty == REQUEST_TTY_FORCE); 1052 1053 /* Stop listening for new connections. */ 1054 channel_stop_listening(ssh); 1055 1056 snprintf(string, sizeof string, 1057 "%c& [backgrounded]\n", efc->escape_char); 1058 buffer_append(berr, string, strlen(string)); 1059 1060 /* Fork into background. */ 1061 pid = fork(); 1062 if (pid < 0) { 1063 error("fork: %.100s", strerror(errno)); 1064 continue; 1065 } 1066 if (pid != 0) { /* This is the parent. */ 1067 /* The parent just exits. */ 1068 exit(0); 1069 } 1070 /* The child continues serving connections. */ 1071 buffer_append(bin, "\004", 1); 1072 /* fake EOF on stdin */ 1073 return -1; 1074 case '?': 1075 print_escape_help(berr, efc->escape_char, 1076 (c && c->ctl_chan != -1), 1077 log_is_on_stderr()); 1078 continue; 1079 1080 case '#': 1081 snprintf(string, sizeof string, "%c#\r\n", 1082 efc->escape_char); 1083 buffer_append(berr, string, strlen(string)); 1084 s = channel_open_message(ssh); 1085 buffer_append(berr, s, strlen(s)); 1086 free(s); 1087 continue; 1088 1089 case 'C': 1090 if (c && c->ctl_chan != -1) 1091 goto noescape; 1092 process_cmdline(ssh); 1093 continue; 1094 1095 default: 1096 if (ch != efc->escape_char) { 1097 buffer_put_char(bin, efc->escape_char); 1098 bytes++; 1099 } 1100 /* Escaped characters fall through here */ 1101 break; 1102 } 1103 } else { 1104 /* 1105 * The previous character was not an escape char. 1106 * Check if this is an escape. 1107 */ 1108 if (last_was_cr && ch == efc->escape_char) { 1109 /* 1110 * It is. Set the flag and continue to 1111 * next character. 1112 */ 1113 efc->escape_pending = 1; 1114 continue; 1115 } 1116 } 1117 1118 /* 1119 * Normal character. Record whether it was a newline, 1120 * and append it to the buffer. 1121 */ 1122 last_was_cr = (ch == '\r' || ch == '\n'); 1123 buffer_put_char(bin, ch); 1124 bytes++; 1125 } 1126 return bytes; 1127 } 1128 1129 /* 1130 * Get packets from the connection input buffer, and process them as long as 1131 * there are packets available. 1132 * 1133 * Any unknown packets received during the actual 1134 * session cause the session to terminate. This is 1135 * intended to make debugging easier since no 1136 * confirmations are sent. Any compatible protocol 1137 * extensions must be negotiated during the 1138 * preparatory phase. 1139 */ 1140 1141 static void 1142 client_process_buffered_input_packets(void) 1143 { 1144 ssh_dispatch_run_fatal(active_state, DISPATCH_NONBLOCK, &quit_pending); 1145 } 1146 1147 /* scan buf[] for '~' before sending data to the peer */ 1148 1149 /* Helper: allocate a new escape_filter_ctx and fill in its escape char */ 1150 void * 1151 client_new_escape_filter_ctx(int escape_char) 1152 { 1153 struct escape_filter_ctx *ret; 1154 1155 ret = xcalloc(1, sizeof(*ret)); 1156 ret->escape_pending = 0; 1157 ret->escape_char = escape_char; 1158 return (void *)ret; 1159 } 1160 1161 /* Free the escape filter context on channel free */ 1162 void 1163 client_filter_cleanup(struct ssh *ssh, int cid, void *ctx) 1164 { 1165 free(ctx); 1166 } 1167 1168 int 1169 client_simple_escape_filter(struct ssh *ssh, Channel *c, char *buf, int len) 1170 { 1171 if (c->extended_usage != CHAN_EXTENDED_WRITE) 1172 return 0; 1173 1174 return process_escapes(ssh, c, c->input, c->output, c->extended, 1175 buf, len); 1176 } 1177 1178 static void 1179 client_channel_closed(struct ssh *ssh, int id, void *arg) 1180 { 1181 channel_cancel_cleanup(ssh, id); 1182 session_closed = 1; 1183 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1184 } 1185 1186 /* 1187 * Implements the interactive session with the server. This is called after 1188 * the user has been authenticated, and a command has been started on the 1189 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character 1190 * used as an escape character for terminating or suspending the session. 1191 */ 1192 int 1193 client_loop(struct ssh *ssh, int have_pty, int escape_char_arg, 1194 int ssh2_chan_id) 1195 { 1196 fd_set *readset = NULL, *writeset = NULL; 1197 double start_time, total_time; 1198 int r, max_fd = 0, max_fd2 = 0, len; 1199 u_int64_t ibytes, obytes; 1200 u_int nalloc = 0; 1201 char buf[100]; 1202 1203 debug("Entering interactive session."); 1204 1205 if (options.control_master && 1206 !option_clear_or_none(options.control_path)) { 1207 debug("pledge: id"); 1208 if (pledge("stdio rpath wpath cpath unix inet dns recvfd proc exec id tty", 1209 NULL) == -1) 1210 fatal("%s pledge(): %s", __func__, strerror(errno)); 1211 1212 } else if (options.forward_x11 || options.permit_local_command) { 1213 debug("pledge: exec"); 1214 if (pledge("stdio rpath wpath cpath unix inet dns proc exec tty", 1215 NULL) == -1) 1216 fatal("%s pledge(): %s", __func__, strerror(errno)); 1217 1218 } else if (options.update_hostkeys) { 1219 debug("pledge: filesystem full"); 1220 if (pledge("stdio rpath wpath cpath unix inet dns proc tty", 1221 NULL) == -1) 1222 fatal("%s pledge(): %s", __func__, strerror(errno)); 1223 1224 } else if (!option_clear_or_none(options.proxy_command) || 1225 fork_after_authentication_flag) { 1226 debug("pledge: proc"); 1227 if (pledge("stdio cpath unix inet dns proc tty", NULL) == -1) 1228 fatal("%s pledge(): %s", __func__, strerror(errno)); 1229 1230 } else { 1231 debug("pledge: network"); 1232 if (pledge("stdio unix inet dns proc tty", NULL) == -1) 1233 fatal("%s pledge(): %s", __func__, strerror(errno)); 1234 } 1235 1236 start_time = monotime_double(); 1237 1238 /* Initialize variables. */ 1239 last_was_cr = 1; 1240 exit_status = -1; 1241 connection_in = packet_get_connection_in(); 1242 connection_out = packet_get_connection_out(); 1243 max_fd = MAXIMUM(connection_in, connection_out); 1244 1245 quit_pending = 0; 1246 1247 /* Initialize buffers. */ 1248 buffer_init(&stderr_buffer); 1249 1250 client_init_dispatch(); 1251 1252 /* 1253 * Set signal handlers, (e.g. to restore non-blocking mode) 1254 * but don't overwrite SIG_IGN, matches behaviour from rsh(1) 1255 */ 1256 if (signal(SIGHUP, SIG_IGN) != SIG_IGN) 1257 signal(SIGHUP, signal_handler); 1258 if (signal(SIGINT, SIG_IGN) != SIG_IGN) 1259 signal(SIGINT, signal_handler); 1260 if (signal(SIGQUIT, SIG_IGN) != SIG_IGN) 1261 signal(SIGQUIT, signal_handler); 1262 if (signal(SIGTERM, SIG_IGN) != SIG_IGN) 1263 signal(SIGTERM, signal_handler); 1264 signal(SIGWINCH, window_change_handler); 1265 1266 if (have_pty) 1267 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1268 1269 session_ident = ssh2_chan_id; 1270 if (session_ident != -1) { 1271 if (escape_char_arg != SSH_ESCAPECHAR_NONE) { 1272 channel_register_filter(ssh, session_ident, 1273 client_simple_escape_filter, NULL, 1274 client_filter_cleanup, 1275 client_new_escape_filter_ctx( 1276 escape_char_arg)); 1277 } 1278 channel_register_cleanup(ssh, session_ident, 1279 client_channel_closed, 0); 1280 } 1281 1282 /* Main loop of the client for the interactive session mode. */ 1283 while (!quit_pending) { 1284 1285 /* Process buffered packets sent by the server. */ 1286 client_process_buffered_input_packets(); 1287 1288 if (session_closed && !channel_still_open(ssh)) 1289 break; 1290 1291 if (ssh_packet_is_rekeying(ssh)) { 1292 debug("rekeying in progress"); 1293 } else if (need_rekeying) { 1294 /* manual rekey request */ 1295 debug("need rekeying"); 1296 if ((r = kex_start_rekex(ssh)) != 0) 1297 fatal("%s: kex_start_rekex: %s", __func__, 1298 ssh_err(r)); 1299 need_rekeying = 0; 1300 } else { 1301 /* 1302 * Make packets from buffered channel data, and 1303 * enqueue them for sending to the server. 1304 */ 1305 if (packet_not_very_much_data_to_write()) 1306 channel_output_poll(ssh); 1307 1308 /* 1309 * Check if the window size has changed, and buffer a 1310 * message about it to the server if so. 1311 */ 1312 client_check_window_change(ssh); 1313 1314 if (quit_pending) 1315 break; 1316 } 1317 /* 1318 * Wait until we have something to do (something becomes 1319 * available on one of the descriptors). 1320 */ 1321 max_fd2 = max_fd; 1322 client_wait_until_can_do_something(ssh, &readset, &writeset, 1323 &max_fd2, &nalloc, ssh_packet_is_rekeying(ssh)); 1324 1325 if (quit_pending) 1326 break; 1327 1328 /* Do channel operations unless rekeying in progress. */ 1329 if (!ssh_packet_is_rekeying(ssh)) 1330 channel_after_select(ssh, readset, writeset); 1331 1332 /* Buffer input from the connection. */ 1333 client_process_net_input(readset); 1334 1335 if (quit_pending) 1336 break; 1337 1338 /* 1339 * Send as much buffered packet data as possible to the 1340 * sender. 1341 */ 1342 if (FD_ISSET(connection_out, writeset)) 1343 packet_write_poll(); 1344 1345 /* 1346 * If we are a backgrounded control master, and the 1347 * timeout has expired without any active client 1348 * connections, then quit. 1349 */ 1350 if (control_persist_exit_time > 0) { 1351 if (monotime() >= control_persist_exit_time) { 1352 debug("ControlPersist timeout expired"); 1353 break; 1354 } 1355 } 1356 } 1357 free(readset); 1358 free(writeset); 1359 1360 /* Terminate the session. */ 1361 1362 /* Stop watching for window change. */ 1363 signal(SIGWINCH, SIG_DFL); 1364 1365 packet_start(SSH2_MSG_DISCONNECT); 1366 packet_put_int(SSH2_DISCONNECT_BY_APPLICATION); 1367 packet_put_cstring("disconnected by user"); 1368 packet_put_cstring(""); /* language tag */ 1369 packet_send(); 1370 packet_write_wait(); 1371 1372 channel_free_all(ssh); 1373 1374 if (have_pty) 1375 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1376 1377 /* restore blocking io */ 1378 if (!isatty(fileno(stdin))) 1379 unset_nonblock(fileno(stdin)); 1380 if (!isatty(fileno(stdout))) 1381 unset_nonblock(fileno(stdout)); 1382 if (!isatty(fileno(stderr))) 1383 unset_nonblock(fileno(stderr)); 1384 1385 /* 1386 * If there was no shell or command requested, there will be no remote 1387 * exit status to be returned. In that case, clear error code if the 1388 * connection was deliberately terminated at this end. 1389 */ 1390 if (no_shell_flag && received_signal == SIGTERM) { 1391 received_signal = 0; 1392 exit_status = 0; 1393 } 1394 1395 if (received_signal) { 1396 verbose("Killed by signal %d.", (int) received_signal); 1397 cleanup_exit(0); 1398 } 1399 1400 /* 1401 * In interactive mode (with pseudo tty) display a message indicating 1402 * that the connection has been closed. 1403 */ 1404 if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) { 1405 snprintf(buf, sizeof buf, 1406 "Connection to %.64s closed.\r\n", host); 1407 buffer_append(&stderr_buffer, buf, strlen(buf)); 1408 } 1409 1410 /* Output any buffered data for stderr. */ 1411 if (buffer_len(&stderr_buffer) > 0) { 1412 len = atomicio(vwrite, fileno(stderr), 1413 buffer_ptr(&stderr_buffer), buffer_len(&stderr_buffer)); 1414 if (len < 0 || (u_int)len != buffer_len(&stderr_buffer)) 1415 error("Write failed flushing stderr buffer."); 1416 else 1417 buffer_consume(&stderr_buffer, len); 1418 } 1419 1420 /* Clear and free any buffers. */ 1421 explicit_bzero(buf, sizeof(buf)); 1422 buffer_free(&stderr_buffer); 1423 1424 /* Report bytes transferred, and transfer rates. */ 1425 total_time = monotime_double() - start_time; 1426 packet_get_bytes(&ibytes, &obytes); 1427 verbose("Transferred: sent %llu, received %llu bytes, in %.1f seconds", 1428 (unsigned long long)obytes, (unsigned long long)ibytes, total_time); 1429 if (total_time > 0) 1430 verbose("Bytes per second: sent %.1f, received %.1f", 1431 obytes / total_time, ibytes / total_time); 1432 /* Return the exit status of the program. */ 1433 debug("Exit status %d", exit_status); 1434 return exit_status; 1435 } 1436 1437 /*********/ 1438 1439 static Channel * 1440 client_request_forwarded_tcpip(struct ssh *ssh, const char *request_type, 1441 int rchan, u_int rwindow, u_int rmaxpack) 1442 { 1443 Channel *c = NULL; 1444 struct sshbuf *b = NULL; 1445 char *listen_address, *originator_address; 1446 u_short listen_port, originator_port; 1447 int r; 1448 1449 /* Get rest of the packet */ 1450 listen_address = packet_get_string(NULL); 1451 listen_port = packet_get_int(); 1452 originator_address = packet_get_string(NULL); 1453 originator_port = packet_get_int(); 1454 packet_check_eom(); 1455 1456 debug("%s: listen %s port %d, originator %s port %d", __func__, 1457 listen_address, listen_port, originator_address, originator_port); 1458 1459 c = channel_connect_by_listen_address(ssh, listen_address, listen_port, 1460 "forwarded-tcpip", originator_address); 1461 1462 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) { 1463 if ((b = sshbuf_new()) == NULL) { 1464 error("%s: alloc reply", __func__); 1465 goto out; 1466 } 1467 /* reconstruct and send to muxclient */ 1468 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 1469 (r = sshbuf_put_u8(b, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1470 (r = sshbuf_put_cstring(b, request_type)) != 0 || 1471 (r = sshbuf_put_u32(b, rchan)) != 0 || 1472 (r = sshbuf_put_u32(b, rwindow)) != 0 || 1473 (r = sshbuf_put_u32(b, rmaxpack)) != 0 || 1474 (r = sshbuf_put_cstring(b, listen_address)) != 0 || 1475 (r = sshbuf_put_u32(b, listen_port)) != 0 || 1476 (r = sshbuf_put_cstring(b, originator_address)) != 0 || 1477 (r = sshbuf_put_u32(b, originator_port)) != 0 || 1478 (r = sshbuf_put_stringb(c->output, b)) != 0) { 1479 error("%s: compose for muxclient %s", __func__, 1480 ssh_err(r)); 1481 goto out; 1482 } 1483 } 1484 1485 out: 1486 sshbuf_free(b); 1487 free(originator_address); 1488 free(listen_address); 1489 return c; 1490 } 1491 1492 static Channel * 1493 client_request_forwarded_streamlocal(struct ssh *ssh, 1494 const char *request_type, int rchan) 1495 { 1496 Channel *c = NULL; 1497 char *listen_path; 1498 1499 /* Get the remote path. */ 1500 listen_path = packet_get_string(NULL); 1501 /* XXX: Skip reserved field for now. */ 1502 if (packet_get_string_ptr(NULL) == NULL) 1503 fatal("%s: packet_get_string_ptr failed", __func__); 1504 packet_check_eom(); 1505 1506 debug("%s: %s", __func__, listen_path); 1507 1508 c = channel_connect_by_listen_path(ssh, listen_path, 1509 "forwarded-streamlocal@openssh.com", "forwarded-streamlocal"); 1510 free(listen_path); 1511 return c; 1512 } 1513 1514 static Channel * 1515 client_request_x11(struct ssh *ssh, const char *request_type, int rchan) 1516 { 1517 Channel *c = NULL; 1518 char *originator; 1519 u_short originator_port; 1520 int sock; 1521 1522 if (!options.forward_x11) { 1523 error("Warning: ssh server tried X11 forwarding."); 1524 error("Warning: this is probably a break-in attempt by a " 1525 "malicious server."); 1526 return NULL; 1527 } 1528 if (x11_refuse_time != 0 && (u_int)monotime() >= x11_refuse_time) { 1529 verbose("Rejected X11 connection after ForwardX11Timeout " 1530 "expired"); 1531 return NULL; 1532 } 1533 originator = packet_get_string(NULL); 1534 originator_port = packet_get_int(); 1535 packet_check_eom(); 1536 /* XXX check permission */ 1537 debug("client_request_x11: request from %s %d", originator, 1538 originator_port); 1539 free(originator); 1540 sock = x11_connect_display(ssh); 1541 if (sock < 0) 1542 return NULL; 1543 c = channel_new(ssh, "x11", 1544 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1545 CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); 1546 c->force_drain = 1; 1547 return c; 1548 } 1549 1550 static Channel * 1551 client_request_agent(struct ssh *ssh, const char *request_type, int rchan) 1552 { 1553 Channel *c = NULL; 1554 int r, sock; 1555 1556 if (!options.forward_agent) { 1557 error("Warning: ssh server tried agent forwarding."); 1558 error("Warning: this is probably a break-in attempt by a " 1559 "malicious server."); 1560 return NULL; 1561 } 1562 if ((r = ssh_get_authentication_socket(&sock)) != 0) { 1563 if (r != SSH_ERR_AGENT_NOT_PRESENT) 1564 debug("%s: ssh_get_authentication_socket: %s", 1565 __func__, ssh_err(r)); 1566 return NULL; 1567 } 1568 c = channel_new(ssh, "authentication agent connection", 1569 SSH_CHANNEL_OPEN, sock, sock, -1, 1570 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, 1571 "authentication agent connection", 1); 1572 c->force_drain = 1; 1573 return c; 1574 } 1575 1576 char * 1577 client_request_tun_fwd(struct ssh *ssh, int tun_mode, 1578 int local_tun, int remote_tun) 1579 { 1580 Channel *c; 1581 int fd; 1582 char *ifname = NULL; 1583 1584 if (tun_mode == SSH_TUNMODE_NO) 1585 return 0; 1586 1587 debug("Requesting tun unit %d in mode %d", local_tun, tun_mode); 1588 1589 /* Open local tunnel device */ 1590 if ((fd = tun_open(local_tun, tun_mode, &ifname)) == -1) { 1591 error("Tunnel device open failed."); 1592 return NULL; 1593 } 1594 debug("Tunnel forwarding using interface %s", ifname); 1595 1596 c = channel_new(ssh, "tun", SSH_CHANNEL_OPENING, fd, fd, -1, 1597 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1); 1598 c->datagram = 1; 1599 1600 packet_start(SSH2_MSG_CHANNEL_OPEN); 1601 packet_put_cstring("tun@openssh.com"); 1602 packet_put_int(c->self); 1603 packet_put_int(c->local_window_max); 1604 packet_put_int(c->local_maxpacket); 1605 packet_put_int(tun_mode); 1606 packet_put_int(remote_tun); 1607 packet_send(); 1608 1609 return ifname; 1610 } 1611 1612 /* XXXX move to generic input handler */ 1613 static int 1614 client_input_channel_open(int type, u_int32_t seq, struct ssh *ssh) 1615 { 1616 Channel *c = NULL; 1617 char *ctype; 1618 int rchan; 1619 u_int rmaxpack, rwindow, len; 1620 1621 ctype = packet_get_string(&len); 1622 rchan = packet_get_int(); 1623 rwindow = packet_get_int(); 1624 rmaxpack = packet_get_int(); 1625 1626 debug("client_input_channel_open: ctype %s rchan %d win %d max %d", 1627 ctype, rchan, rwindow, rmaxpack); 1628 1629 if (strcmp(ctype, "forwarded-tcpip") == 0) { 1630 c = client_request_forwarded_tcpip(ssh, ctype, rchan, rwindow, 1631 rmaxpack); 1632 } else if (strcmp(ctype, "forwarded-streamlocal@openssh.com") == 0) { 1633 c = client_request_forwarded_streamlocal(ssh, ctype, rchan); 1634 } else if (strcmp(ctype, "x11") == 0) { 1635 c = client_request_x11(ssh, ctype, rchan); 1636 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) { 1637 c = client_request_agent(ssh, ctype, rchan); 1638 } 1639 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) { 1640 debug3("proxied to downstream: %s", ctype); 1641 } else if (c != NULL) { 1642 debug("confirm %s", ctype); 1643 c->remote_id = rchan; 1644 c->have_remote_id = 1; 1645 c->remote_window = rwindow; 1646 c->remote_maxpacket = rmaxpack; 1647 if (c->type != SSH_CHANNEL_CONNECTING) { 1648 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); 1649 packet_put_int(c->remote_id); 1650 packet_put_int(c->self); 1651 packet_put_int(c->local_window); 1652 packet_put_int(c->local_maxpacket); 1653 packet_send(); 1654 } 1655 } else { 1656 debug("failure %s", ctype); 1657 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); 1658 packet_put_int(rchan); 1659 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED); 1660 packet_put_cstring("open failed"); 1661 packet_put_cstring(""); 1662 packet_send(); 1663 } 1664 free(ctype); 1665 return 0; 1666 } 1667 1668 static int 1669 client_input_channel_req(int type, u_int32_t seq, struct ssh *ssh) 1670 { 1671 Channel *c = NULL; 1672 int exitval, id, reply, success = 0; 1673 char *rtype; 1674 1675 id = packet_get_int(); 1676 c = channel_lookup(ssh, id); 1677 if (channel_proxy_upstream(c, type, seq, ssh)) 1678 return 0; 1679 rtype = packet_get_string(NULL); 1680 reply = packet_get_char(); 1681 1682 debug("client_input_channel_req: channel %d rtype %s reply %d", 1683 id, rtype, reply); 1684 1685 if (id == -1) { 1686 error("client_input_channel_req: request for channel -1"); 1687 } else if (c == NULL) { 1688 error("client_input_channel_req: channel %d: " 1689 "unknown channel", id); 1690 } else if (strcmp(rtype, "eow@openssh.com") == 0) { 1691 packet_check_eom(); 1692 chan_rcvd_eow(ssh, c); 1693 } else if (strcmp(rtype, "exit-status") == 0) { 1694 exitval = packet_get_int(); 1695 if (c->ctl_chan != -1) { 1696 mux_exit_message(ssh, c, exitval); 1697 success = 1; 1698 } else if (id == session_ident) { 1699 /* Record exit value of local session */ 1700 success = 1; 1701 exit_status = exitval; 1702 } else { 1703 /* Probably for a mux channel that has already closed */ 1704 debug("%s: no sink for exit-status on channel %d", 1705 __func__, id); 1706 } 1707 packet_check_eom(); 1708 } 1709 if (reply && c != NULL && !(c->flags & CHAN_CLOSE_SENT)) { 1710 if (!c->have_remote_id) 1711 fatal("%s: channel %d: no remote_id", 1712 __func__, c->self); 1713 packet_start(success ? 1714 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE); 1715 packet_put_int(c->remote_id); 1716 packet_send(); 1717 } 1718 free(rtype); 1719 return 0; 1720 } 1721 1722 struct hostkeys_update_ctx { 1723 /* The hostname and (optionally) IP address string for the server */ 1724 char *host_str, *ip_str; 1725 1726 /* 1727 * Keys received from the server and a flag for each indicating 1728 * whether they already exist in known_hosts. 1729 * keys_seen is filled in by hostkeys_find() and later (for new 1730 * keys) by client_global_hostkeys_private_confirm(). 1731 */ 1732 struct sshkey **keys; 1733 int *keys_seen; 1734 size_t nkeys, nnew; 1735 1736 /* 1737 * Keys that are in known_hosts, but were not present in the update 1738 * from the server (i.e. scheduled to be deleted). 1739 * Filled in by hostkeys_find(). 1740 */ 1741 struct sshkey **old_keys; 1742 size_t nold; 1743 }; 1744 1745 static void 1746 hostkeys_update_ctx_free(struct hostkeys_update_ctx *ctx) 1747 { 1748 size_t i; 1749 1750 if (ctx == NULL) 1751 return; 1752 for (i = 0; i < ctx->nkeys; i++) 1753 sshkey_free(ctx->keys[i]); 1754 free(ctx->keys); 1755 free(ctx->keys_seen); 1756 for (i = 0; i < ctx->nold; i++) 1757 sshkey_free(ctx->old_keys[i]); 1758 free(ctx->old_keys); 1759 free(ctx->host_str); 1760 free(ctx->ip_str); 1761 free(ctx); 1762 } 1763 1764 static int 1765 hostkeys_find(struct hostkey_foreach_line *l, void *_ctx) 1766 { 1767 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 1768 size_t i; 1769 struct sshkey **tmp; 1770 1771 if (l->status != HKF_STATUS_MATCHED || l->key == NULL) 1772 return 0; 1773 1774 /* Mark off keys we've already seen for this host */ 1775 for (i = 0; i < ctx->nkeys; i++) { 1776 if (sshkey_equal(l->key, ctx->keys[i])) { 1777 debug3("%s: found %s key at %s:%ld", __func__, 1778 sshkey_ssh_name(ctx->keys[i]), l->path, l->linenum); 1779 ctx->keys_seen[i] = 1; 1780 return 0; 1781 } 1782 } 1783 /* This line contained a key that not offered by the server */ 1784 debug3("%s: deprecated %s key at %s:%ld", __func__, 1785 sshkey_ssh_name(l->key), l->path, l->linenum); 1786 if ((tmp = recallocarray(ctx->old_keys, ctx->nold, ctx->nold + 1, 1787 sizeof(*ctx->old_keys))) == NULL) 1788 fatal("%s: recallocarray failed nold = %zu", 1789 __func__, ctx->nold); 1790 ctx->old_keys = tmp; 1791 ctx->old_keys[ctx->nold++] = l->key; 1792 l->key = NULL; 1793 1794 return 0; 1795 } 1796 1797 static void 1798 update_known_hosts(struct hostkeys_update_ctx *ctx) 1799 { 1800 int r, was_raw = 0; 1801 int loglevel = options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK ? 1802 SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_VERBOSE; 1803 char *fp, *response; 1804 size_t i; 1805 1806 for (i = 0; i < ctx->nkeys; i++) { 1807 if (ctx->keys_seen[i] != 2) 1808 continue; 1809 if ((fp = sshkey_fingerprint(ctx->keys[i], 1810 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 1811 fatal("%s: sshkey_fingerprint failed", __func__); 1812 do_log2(loglevel, "Learned new hostkey: %s %s", 1813 sshkey_type(ctx->keys[i]), fp); 1814 free(fp); 1815 } 1816 for (i = 0; i < ctx->nold; i++) { 1817 if ((fp = sshkey_fingerprint(ctx->old_keys[i], 1818 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 1819 fatal("%s: sshkey_fingerprint failed", __func__); 1820 do_log2(loglevel, "Deprecating obsolete hostkey: %s %s", 1821 sshkey_type(ctx->old_keys[i]), fp); 1822 free(fp); 1823 } 1824 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) { 1825 if (get_saved_tio() != NULL) { 1826 leave_raw_mode(1); 1827 was_raw = 1; 1828 } 1829 response = NULL; 1830 for (i = 0; !quit_pending && i < 3; i++) { 1831 free(response); 1832 response = read_passphrase("Accept updated hostkeys? " 1833 "(yes/no): ", RP_ECHO); 1834 if (strcasecmp(response, "yes") == 0) 1835 break; 1836 else if (quit_pending || response == NULL || 1837 strcasecmp(response, "no") == 0) { 1838 options.update_hostkeys = 0; 1839 break; 1840 } else { 1841 do_log2(loglevel, "Please enter " 1842 "\"yes\" or \"no\""); 1843 } 1844 } 1845 if (quit_pending || i >= 3 || response == NULL) 1846 options.update_hostkeys = 0; 1847 free(response); 1848 if (was_raw) 1849 enter_raw_mode(1); 1850 } 1851 1852 /* 1853 * Now that all the keys are verified, we can go ahead and replace 1854 * them in known_hosts (assuming SSH_UPDATE_HOSTKEYS_ASK didn't 1855 * cancel the operation). 1856 */ 1857 if (options.update_hostkeys != 0 && 1858 (r = hostfile_replace_entries(options.user_hostfiles[0], 1859 ctx->host_str, ctx->ip_str, ctx->keys, ctx->nkeys, 1860 options.hash_known_hosts, 0, 1861 options.fingerprint_hash)) != 0) 1862 error("%s: hostfile_replace_entries failed: %s", 1863 __func__, ssh_err(r)); 1864 } 1865 1866 static void 1867 client_global_hostkeys_private_confirm(struct ssh *ssh, int type, 1868 u_int32_t seq, void *_ctx) 1869 { 1870 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 1871 size_t i, ndone; 1872 struct sshbuf *signdata; 1873 int r, kexsigtype, use_kexsigtype; 1874 const u_char *sig; 1875 size_t siglen; 1876 1877 if (ctx->nnew == 0) 1878 fatal("%s: ctx->nnew == 0", __func__); /* sanity */ 1879 if (type != SSH2_MSG_REQUEST_SUCCESS) { 1880 error("Server failed to confirm ownership of " 1881 "private host keys"); 1882 hostkeys_update_ctx_free(ctx); 1883 return; 1884 } 1885 kexsigtype = sshkey_type_plain( 1886 sshkey_type_from_name(ssh->kex->hostkey_alg)); 1887 1888 if ((signdata = sshbuf_new()) == NULL) 1889 fatal("%s: sshbuf_new failed", __func__); 1890 /* Don't want to accidentally accept an unbound signature */ 1891 if (ssh->kex->session_id_len == 0) 1892 fatal("%s: ssh->kex->session_id_len == 0", __func__); 1893 /* 1894 * Expect a signature for each of the ctx->nnew private keys we 1895 * haven't seen before. They will be in the same order as the 1896 * ctx->keys where the corresponding ctx->keys_seen[i] == 0. 1897 */ 1898 for (ndone = i = 0; i < ctx->nkeys; i++) { 1899 if (ctx->keys_seen[i]) 1900 continue; 1901 /* Prepare data to be signed: session ID, unique string, key */ 1902 sshbuf_reset(signdata); 1903 if ( (r = sshbuf_put_cstring(signdata, 1904 "hostkeys-prove-00@openssh.com")) != 0 || 1905 (r = sshbuf_put_string(signdata, ssh->kex->session_id, 1906 ssh->kex->session_id_len)) != 0 || 1907 (r = sshkey_puts(ctx->keys[i], signdata)) != 0) 1908 fatal("%s: failed to prepare signature: %s", 1909 __func__, ssh_err(r)); 1910 /* Extract and verify signature */ 1911 if ((r = sshpkt_get_string_direct(ssh, &sig, &siglen)) != 0) { 1912 error("%s: couldn't parse message: %s", 1913 __func__, ssh_err(r)); 1914 goto out; 1915 } 1916 /* 1917 * For RSA keys, prefer to use the signature type negotiated 1918 * during KEX to the default (SHA1). 1919 */ 1920 use_kexsigtype = kexsigtype == KEY_RSA && 1921 sshkey_type_plain(ctx->keys[i]->type) == KEY_RSA; 1922 if ((r = sshkey_verify(ctx->keys[i], sig, siglen, 1923 sshbuf_ptr(signdata), sshbuf_len(signdata), 1924 use_kexsigtype ? ssh->kex->hostkey_alg : NULL, 0)) != 0) { 1925 error("%s: server gave bad signature for %s key %zu", 1926 __func__, sshkey_type(ctx->keys[i]), i); 1927 goto out; 1928 } 1929 /* Key is good. Mark it as 'seen' */ 1930 ctx->keys_seen[i] = 2; 1931 ndone++; 1932 } 1933 if (ndone != ctx->nnew) 1934 fatal("%s: ndone != ctx->nnew (%zu / %zu)", __func__, 1935 ndone, ctx->nnew); /* Shouldn't happen */ 1936 ssh_packet_check_eom(ssh); 1937 1938 /* Make the edits to known_hosts */ 1939 update_known_hosts(ctx); 1940 out: 1941 hostkeys_update_ctx_free(ctx); 1942 } 1943 1944 /* 1945 * Returns non-zero if the key is accepted by HostkeyAlgorithms. 1946 * Made slightly less trivial by the multiple RSA signature algorithm names. 1947 */ 1948 static int 1949 key_accepted_by_hostkeyalgs(const struct sshkey *key) 1950 { 1951 const char *ktype = sshkey_ssh_name(key); 1952 const char *hostkeyalgs = options.hostkeyalgorithms != NULL ? 1953 options.hostkeyalgorithms : KEX_DEFAULT_PK_ALG; 1954 1955 if (key == NULL || key->type == KEY_UNSPEC) 1956 return 0; 1957 if (key->type == KEY_RSA && 1958 (match_pattern_list("rsa-sha2-256", hostkeyalgs, 0) == 1 || 1959 match_pattern_list("rsa-sha2-512", hostkeyalgs, 0) == 1)) 1960 return 1; 1961 return match_pattern_list(ktype, hostkeyalgs, 0) == 1; 1962 } 1963 1964 /* 1965 * Handle hostkeys-00@openssh.com global request to inform the client of all 1966 * the server's hostkeys. The keys are checked against the user's 1967 * HostkeyAlgorithms preference before they are accepted. 1968 */ 1969 static int 1970 client_input_hostkeys(void) 1971 { 1972 struct ssh *ssh = active_state; /* XXX */ 1973 const u_char *blob = NULL; 1974 size_t i, len = 0; 1975 struct sshbuf *buf = NULL; 1976 struct sshkey *key = NULL, **tmp; 1977 int r; 1978 char *fp; 1979 static int hostkeys_seen = 0; /* XXX use struct ssh */ 1980 extern struct sockaddr_storage hostaddr; /* XXX from ssh.c */ 1981 struct hostkeys_update_ctx *ctx = NULL; 1982 1983 if (hostkeys_seen) 1984 fatal("%s: server already sent hostkeys", __func__); 1985 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK && 1986 options.batch_mode) 1987 return 1; /* won't ask in batchmode, so don't even try */ 1988 if (!options.update_hostkeys || options.num_user_hostfiles <= 0) 1989 return 1; 1990 1991 ctx = xcalloc(1, sizeof(*ctx)); 1992 while (ssh_packet_remaining(ssh) > 0) { 1993 sshkey_free(key); 1994 key = NULL; 1995 if ((r = sshpkt_get_string_direct(ssh, &blob, &len)) != 0) { 1996 error("%s: couldn't parse message: %s", 1997 __func__, ssh_err(r)); 1998 goto out; 1999 } 2000 if ((r = sshkey_from_blob(blob, len, &key)) != 0) { 2001 error("%s: parse key: %s", __func__, ssh_err(r)); 2002 goto out; 2003 } 2004 fp = sshkey_fingerprint(key, options.fingerprint_hash, 2005 SSH_FP_DEFAULT); 2006 debug3("%s: received %s key %s", __func__, 2007 sshkey_type(key), fp); 2008 free(fp); 2009 2010 if (!key_accepted_by_hostkeyalgs(key)) { 2011 debug3("%s: %s key not permitted by HostkeyAlgorithms", 2012 __func__, sshkey_ssh_name(key)); 2013 continue; 2014 } 2015 /* Skip certs */ 2016 if (sshkey_is_cert(key)) { 2017 debug3("%s: %s key is a certificate; skipping", 2018 __func__, sshkey_ssh_name(key)); 2019 continue; 2020 } 2021 /* Ensure keys are unique */ 2022 for (i = 0; i < ctx->nkeys; i++) { 2023 if (sshkey_equal(key, ctx->keys[i])) { 2024 error("%s: received duplicated %s host key", 2025 __func__, sshkey_ssh_name(key)); 2026 goto out; 2027 } 2028 } 2029 /* Key is good, record it */ 2030 if ((tmp = recallocarray(ctx->keys, ctx->nkeys, ctx->nkeys + 1, 2031 sizeof(*ctx->keys))) == NULL) 2032 fatal("%s: recallocarray failed nkeys = %zu", 2033 __func__, ctx->nkeys); 2034 ctx->keys = tmp; 2035 ctx->keys[ctx->nkeys++] = key; 2036 key = NULL; 2037 } 2038 2039 if (ctx->nkeys == 0) { 2040 debug("%s: server sent no hostkeys", __func__); 2041 goto out; 2042 } 2043 2044 if ((ctx->keys_seen = calloc(ctx->nkeys, 2045 sizeof(*ctx->keys_seen))) == NULL) 2046 fatal("%s: calloc failed", __func__); 2047 2048 get_hostfile_hostname_ipaddr(host, 2049 options.check_host_ip ? (struct sockaddr *)&hostaddr : NULL, 2050 options.port, &ctx->host_str, 2051 options.check_host_ip ? &ctx->ip_str : NULL); 2052 2053 /* Find which keys we already know about. */ 2054 if ((r = hostkeys_foreach(options.user_hostfiles[0], hostkeys_find, 2055 ctx, ctx->host_str, ctx->ip_str, 2056 HKF_WANT_PARSE_KEY|HKF_WANT_MATCH)) != 0) { 2057 error("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r)); 2058 goto out; 2059 } 2060 2061 /* Figure out if we have any new keys to add */ 2062 ctx->nnew = 0; 2063 for (i = 0; i < ctx->nkeys; i++) { 2064 if (!ctx->keys_seen[i]) 2065 ctx->nnew++; 2066 } 2067 2068 debug3("%s: %zu keys from server: %zu new, %zu retained. %zu to remove", 2069 __func__, ctx->nkeys, ctx->nnew, ctx->nkeys - ctx->nnew, ctx->nold); 2070 2071 if (ctx->nnew == 0 && ctx->nold != 0) { 2072 /* We have some keys to remove. Just do it. */ 2073 update_known_hosts(ctx); 2074 } else if (ctx->nnew != 0) { 2075 /* 2076 * We have received hitherto-unseen keys from the server. 2077 * Ask the server to confirm ownership of the private halves. 2078 */ 2079 debug3("%s: asking server to prove ownership for %zu keys", 2080 __func__, ctx->nnew); 2081 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 2082 (r = sshpkt_put_cstring(ssh, 2083 "hostkeys-prove-00@openssh.com")) != 0 || 2084 (r = sshpkt_put_u8(ssh, 1)) != 0) /* bool: want reply */ 2085 fatal("%s: cannot prepare packet: %s", 2086 __func__, ssh_err(r)); 2087 if ((buf = sshbuf_new()) == NULL) 2088 fatal("%s: sshbuf_new", __func__); 2089 for (i = 0; i < ctx->nkeys; i++) { 2090 if (ctx->keys_seen[i]) 2091 continue; 2092 sshbuf_reset(buf); 2093 if ((r = sshkey_putb(ctx->keys[i], buf)) != 0) 2094 fatal("%s: sshkey_putb: %s", 2095 __func__, ssh_err(r)); 2096 if ((r = sshpkt_put_stringb(ssh, buf)) != 0) 2097 fatal("%s: sshpkt_put_string: %s", 2098 __func__, ssh_err(r)); 2099 } 2100 if ((r = sshpkt_send(ssh)) != 0) 2101 fatal("%s: sshpkt_send: %s", __func__, ssh_err(r)); 2102 client_register_global_confirm( 2103 client_global_hostkeys_private_confirm, ctx); 2104 ctx = NULL; /* will be freed in callback */ 2105 } 2106 2107 /* Success */ 2108 out: 2109 hostkeys_update_ctx_free(ctx); 2110 sshkey_free(key); 2111 sshbuf_free(buf); 2112 /* 2113 * NB. Return success for all cases. The server doesn't need to know 2114 * what the client does with its hosts file. 2115 */ 2116 return 1; 2117 } 2118 2119 static int 2120 client_input_global_request(int type, u_int32_t seq, struct ssh *ssh) 2121 { 2122 char *rtype; 2123 int want_reply; 2124 int success = 0; 2125 2126 rtype = packet_get_cstring(NULL); 2127 want_reply = packet_get_char(); 2128 debug("client_input_global_request: rtype %s want_reply %d", 2129 rtype, want_reply); 2130 if (strcmp(rtype, "hostkeys-00@openssh.com") == 0) 2131 success = client_input_hostkeys(); 2132 if (want_reply) { 2133 packet_start(success ? 2134 SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE); 2135 packet_send(); 2136 packet_write_wait(); 2137 } 2138 free(rtype); 2139 return 0; 2140 } 2141 2142 void 2143 client_session2_setup(struct ssh *ssh, int id, int want_tty, int want_subsystem, 2144 const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env) 2145 { 2146 int len; 2147 Channel *c = NULL; 2148 2149 debug2("%s: id %d", __func__, id); 2150 2151 if ((c = channel_lookup(ssh, id)) == NULL) 2152 fatal("%s: channel %d: unknown channel", __func__, id); 2153 2154 packet_set_interactive(want_tty, 2155 options.ip_qos_interactive, options.ip_qos_bulk); 2156 2157 if (want_tty) { 2158 struct winsize ws; 2159 2160 /* Store window size in the packet. */ 2161 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0) 2162 memset(&ws, 0, sizeof(ws)); 2163 2164 channel_request_start(ssh, id, "pty-req", 1); 2165 client_expect_confirm(ssh, id, "PTY allocation", CONFIRM_TTY); 2166 packet_put_cstring(term != NULL ? term : ""); 2167 packet_put_int((u_int)ws.ws_col); 2168 packet_put_int((u_int)ws.ws_row); 2169 packet_put_int((u_int)ws.ws_xpixel); 2170 packet_put_int((u_int)ws.ws_ypixel); 2171 if (tiop == NULL) 2172 tiop = get_saved_tio(); 2173 tty_make_modes(-1, tiop); 2174 packet_send(); 2175 /* XXX wait for reply */ 2176 c->client_tty = 1; 2177 } 2178 2179 /* Transfer any environment variables from client to server */ 2180 if (options.num_send_env != 0 && env != NULL) { 2181 int i, j, matched; 2182 char *name, *val; 2183 2184 debug("Sending environment."); 2185 for (i = 0; env[i] != NULL; i++) { 2186 /* Split */ 2187 name = xstrdup(env[i]); 2188 if ((val = strchr(name, '=')) == NULL) { 2189 free(name); 2190 continue; 2191 } 2192 *val++ = '\0'; 2193 2194 matched = 0; 2195 for (j = 0; j < options.num_send_env; j++) { 2196 if (match_pattern(name, options.send_env[j])) { 2197 matched = 1; 2198 break; 2199 } 2200 } 2201 if (!matched) { 2202 debug3("Ignored env %s", name); 2203 free(name); 2204 continue; 2205 } 2206 2207 debug("Sending env %s = %s", name, val); 2208 channel_request_start(ssh, id, "env", 0); 2209 packet_put_cstring(name); 2210 packet_put_cstring(val); 2211 packet_send(); 2212 free(name); 2213 } 2214 } 2215 2216 len = buffer_len(cmd); 2217 if (len > 0) { 2218 if (len > 900) 2219 len = 900; 2220 if (want_subsystem) { 2221 debug("Sending subsystem: %.*s", 2222 len, (u_char*)buffer_ptr(cmd)); 2223 channel_request_start(ssh, id, "subsystem", 1); 2224 client_expect_confirm(ssh, id, "subsystem", 2225 CONFIRM_CLOSE); 2226 } else { 2227 debug("Sending command: %.*s", 2228 len, (u_char*)buffer_ptr(cmd)); 2229 channel_request_start(ssh, id, "exec", 1); 2230 client_expect_confirm(ssh, id, "exec", CONFIRM_CLOSE); 2231 } 2232 packet_put_string(buffer_ptr(cmd), buffer_len(cmd)); 2233 packet_send(); 2234 } else { 2235 channel_request_start(ssh, id, "shell", 1); 2236 client_expect_confirm(ssh, id, "shell", CONFIRM_CLOSE); 2237 packet_send(); 2238 } 2239 } 2240 2241 static void 2242 client_init_dispatch(void) 2243 { 2244 dispatch_init(&dispatch_protocol_error); 2245 2246 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); 2247 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); 2248 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); 2249 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); 2250 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open); 2251 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 2252 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 2253 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req); 2254 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); 2255 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm); 2256 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm); 2257 dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request); 2258 2259 /* rekeying */ 2260 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); 2261 2262 /* global request reply messages */ 2263 dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply); 2264 dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply); 2265 } 2266 2267 void 2268 client_stop_mux(void) 2269 { 2270 if (options.control_path != NULL && muxserver_sock != -1) 2271 unlink(options.control_path); 2272 /* 2273 * If we are in persist mode, or don't have a shell, signal that we 2274 * should close when all active channels are closed. 2275 */ 2276 if (options.control_persist || no_shell_flag) { 2277 session_closed = 1; 2278 setproctitle("[stopped mux]"); 2279 } 2280 } 2281 2282 /* client specific fatal cleanup */ 2283 void 2284 cleanup_exit(int i) 2285 { 2286 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 2287 leave_non_blocking(); 2288 if (options.control_path != NULL && muxserver_sock != -1) 2289 unlink(options.control_path); 2290 ssh_kill_proxy_command(); 2291 _exit(i); 2292 } 2293