1 /* $OpenBSD: clientloop.c,v 1.305 2017/09/19 04:24:22 djm Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * The main loop for the interactive session (client side). 7 * 8 * As far as I am concerned, the code I have written for this software 9 * can be used freely for any purpose. Any derived versions of this 10 * software must be clearly marked as such, and if the derived work is 11 * incompatible with the protocol description in the RFC file, it must be 12 * called by a name other than "ssh" or "Secure Shell". 13 * 14 * 15 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 16 * 17 * Redistribution and use in source and binary forms, with or without 18 * modification, are permitted provided that the following conditions 19 * are met: 20 * 1. Redistributions of source code must retain the above copyright 21 * notice, this list of conditions and the following disclaimer. 22 * 2. Redistributions in binary form must reproduce the above copyright 23 * notice, this list of conditions and the following disclaimer in the 24 * documentation and/or other materials provided with the distribution. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 27 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 28 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 29 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 30 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 31 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 35 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 36 * 37 * 38 * SSH2 support added by Markus Friedl. 39 * Copyright (c) 1999, 2000, 2001 Markus Friedl. All rights reserved. 40 * 41 * Redistribution and use in source and binary forms, with or without 42 * modification, are permitted provided that the following conditions 43 * are met: 44 * 1. Redistributions of source code must retain the above copyright 45 * notice, this list of conditions and the following disclaimer. 46 * 2. Redistributions in binary form must reproduce the above copyright 47 * notice, this list of conditions and the following disclaimer in the 48 * documentation and/or other materials provided with the distribution. 49 * 50 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 51 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 52 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 53 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 54 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 55 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 56 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 57 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 58 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 59 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 60 */ 61 62 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 signal(SIGWINCH, window_change_handler); 206 } 207 208 /* 209 * Signal handler for signals that cause the program to terminate. These 210 * signals must be trapped to restore terminal modes. 211 */ 212 /*ARGSUSED */ 213 static void 214 signal_handler(int sig) 215 { 216 received_signal = sig; 217 quit_pending = 1; 218 } 219 220 /* 221 * Returns current time in seconds from Jan 1, 1970 with the maximum 222 * available resolution. 223 */ 224 225 static double 226 get_current_time(void) 227 { 228 struct timeval tv; 229 gettimeofday(&tv, NULL); 230 return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0; 231 } 232 233 /* 234 * Sets control_persist_exit_time to the absolute time when the 235 * backgrounded control master should exit due to expiry of the 236 * ControlPersist timeout. Sets it to 0 if we are not a backgrounded 237 * control master process, or if there is no ControlPersist timeout. 238 */ 239 static void 240 set_control_persist_exit_time(struct ssh *ssh) 241 { 242 if (muxserver_sock == -1 || !options.control_persist 243 || options.control_persist_timeout == 0) { 244 /* not using a ControlPersist timeout */ 245 control_persist_exit_time = 0; 246 } else if (channel_still_open(ssh)) { 247 /* some client connections are still open */ 248 if (control_persist_exit_time > 0) 249 debug2("%s: cancel scheduled exit", __func__); 250 control_persist_exit_time = 0; 251 } else if (control_persist_exit_time <= 0) { 252 /* a client connection has recently closed */ 253 control_persist_exit_time = monotime() + 254 (time_t)options.control_persist_timeout; 255 debug2("%s: schedule exit in %d seconds", __func__, 256 options.control_persist_timeout); 257 } 258 /* else we are already counting down to the timeout */ 259 } 260 261 #define SSH_X11_VALID_DISPLAY_CHARS ":/.-_" 262 static int 263 client_x11_display_valid(const char *display) 264 { 265 size_t i, dlen; 266 267 if (display == NULL) 268 return 0; 269 270 dlen = strlen(display); 271 for (i = 0; i < dlen; i++) { 272 if (!isalnum((u_char)display[i]) && 273 strchr(SSH_X11_VALID_DISPLAY_CHARS, display[i]) == NULL) { 274 debug("Invalid character '%c' in DISPLAY", display[i]); 275 return 0; 276 } 277 } 278 return 1; 279 } 280 281 #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1" 282 #define X11_TIMEOUT_SLACK 60 283 int 284 client_x11_get_proto(struct ssh *ssh, const char *display, 285 const char *xauth_path, u_int trusted, u_int timeout, 286 char **_proto, char **_data) 287 { 288 char cmd[1024], line[512], xdisplay[512]; 289 char xauthfile[PATH_MAX], xauthdir[PATH_MAX]; 290 static char proto[512], data[512]; 291 FILE *f; 292 int got_data = 0, generated = 0, do_unlink = 0, r; 293 struct stat st; 294 u_int now, x11_timeout_real; 295 296 *_proto = proto; 297 *_data = data; 298 proto[0] = data[0] = xauthfile[0] = xauthdir[0] = '\0'; 299 300 if (!client_x11_display_valid(display)) { 301 if (display != NULL) 302 logit("DISPLAY \"%s\" invalid; disabling X11 forwarding", 303 display); 304 return -1; 305 } 306 if (xauth_path != NULL && stat(xauth_path, &st) == -1) { 307 debug("No xauth program."); 308 xauth_path = NULL; 309 } 310 311 if (xauth_path != NULL) { 312 /* 313 * Handle FamilyLocal case where $DISPLAY does 314 * not match an authorization entry. For this we 315 * just try "xauth list unix:displaynum.screennum". 316 * XXX: "localhost" match to determine FamilyLocal 317 * is not perfect. 318 */ 319 if (strncmp(display, "localhost:", 10) == 0) { 320 if ((r = snprintf(xdisplay, sizeof(xdisplay), "unix:%s", 321 display + 10)) < 0 || 322 (size_t)r >= sizeof(xdisplay)) { 323 error("%s: display name too long", __func__); 324 return -1; 325 } 326 display = xdisplay; 327 } 328 if (trusted == 0) { 329 /* 330 * Generate an untrusted X11 auth cookie. 331 * 332 * The authentication cookie should briefly outlive 333 * ssh's willingness to forward X11 connections to 334 * avoid nasty fail-open behaviour in the X server. 335 */ 336 mktemp_proto(xauthdir, sizeof(xauthdir)); 337 if (mkdtemp(xauthdir) == NULL) { 338 error("%s: mkdtemp: %s", 339 __func__, strerror(errno)); 340 return -1; 341 } 342 do_unlink = 1; 343 if ((r = snprintf(xauthfile, sizeof(xauthfile), 344 "%s/xauthfile", xauthdir)) < 0 || 345 (size_t)r >= sizeof(xauthfile)) { 346 error("%s: xauthfile path too long", __func__); 347 unlink(xauthfile); 348 rmdir(xauthdir); 349 return -1; 350 } 351 352 if (timeout >= UINT_MAX - X11_TIMEOUT_SLACK) 353 x11_timeout_real = UINT_MAX; 354 else 355 x11_timeout_real = timeout + X11_TIMEOUT_SLACK; 356 if ((r = snprintf(cmd, sizeof(cmd), 357 "%s -f %s generate %s " SSH_X11_PROTO 358 " untrusted timeout %u 2>" _PATH_DEVNULL, 359 xauth_path, xauthfile, display, 360 x11_timeout_real)) < 0 || 361 (size_t)r >= sizeof(cmd)) 362 fatal("%s: cmd too long", __func__); 363 debug2("%s: %s", __func__, cmd); 364 if (x11_refuse_time == 0) { 365 now = monotime() + 1; 366 if (UINT_MAX - timeout < now) 367 x11_refuse_time = UINT_MAX; 368 else 369 x11_refuse_time = now + timeout; 370 channel_set_x11_refuse_time(ssh, 371 x11_refuse_time); 372 } 373 if (system(cmd) == 0) 374 generated = 1; 375 } 376 377 /* 378 * When in untrusted mode, we read the cookie only if it was 379 * successfully generated as an untrusted one in the step 380 * above. 381 */ 382 if (trusted || generated) { 383 snprintf(cmd, sizeof(cmd), 384 "%s %s%s list %s 2>" _PATH_DEVNULL, 385 xauth_path, 386 generated ? "-f " : "" , 387 generated ? xauthfile : "", 388 display); 389 debug2("x11_get_proto: %s", cmd); 390 f = popen(cmd, "r"); 391 if (f && fgets(line, sizeof(line), f) && 392 sscanf(line, "%*s %511s %511s", proto, data) == 2) 393 got_data = 1; 394 if (f) 395 pclose(f); 396 } 397 } 398 399 if (do_unlink) { 400 unlink(xauthfile); 401 rmdir(xauthdir); 402 } 403 404 /* Don't fall back to fake X11 data for untrusted forwarding */ 405 if (!trusted && !got_data) { 406 error("Warning: untrusted X11 forwarding setup failed: " 407 "xauth key data not generated"); 408 return -1; 409 } 410 411 /* 412 * If we didn't get authentication data, just make up some 413 * data. The forwarding code will check the validity of the 414 * response anyway, and substitute this data. The X11 415 * server, however, will ignore this fake data and use 416 * whatever authentication mechanisms it was using otherwise 417 * for the local connection. 418 */ 419 if (!got_data) { 420 u_int8_t rnd[16]; 421 u_int i; 422 423 logit("Warning: No xauth data; " 424 "using fake authentication data for X11 forwarding."); 425 strlcpy(proto, SSH_X11_PROTO, sizeof proto); 426 arc4random_buf(rnd, sizeof(rnd)); 427 for (i = 0; i < sizeof(rnd); i++) { 428 snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", 429 rnd[i]); 430 } 431 } 432 433 return 0; 434 } 435 436 /* 437 * Checks if the client window has changed, and sends a packet about it to 438 * the server if so. The actual change is detected elsewhere (by a software 439 * interrupt on Unix); this just checks the flag and sends a message if 440 * appropriate. 441 */ 442 443 static void 444 client_check_window_change(struct ssh *ssh) 445 { 446 if (!received_window_change_signal) 447 return; 448 /** XXX race */ 449 received_window_change_signal = 0; 450 451 debug2("%s: changed", __func__); 452 453 channel_send_window_changes(ssh); 454 } 455 456 static int 457 client_global_request_reply(int type, u_int32_t seq, struct ssh *ssh) 458 { 459 struct global_confirm *gc; 460 461 if ((gc = TAILQ_FIRST(&global_confirms)) == NULL) 462 return 0; 463 if (gc->cb != NULL) 464 gc->cb(ssh, type, seq, gc->ctx); 465 if (--gc->ref_count <= 0) { 466 TAILQ_REMOVE(&global_confirms, gc, entry); 467 explicit_bzero(gc, sizeof(*gc)); 468 free(gc); 469 } 470 471 packet_set_alive_timeouts(0); 472 return 0; 473 } 474 475 static void 476 server_alive_check(void) 477 { 478 if (packet_inc_alive_timeouts() > options.server_alive_count_max) { 479 logit("Timeout, server %s not responding.", host); 480 cleanup_exit(255); 481 } 482 packet_start(SSH2_MSG_GLOBAL_REQUEST); 483 packet_put_cstring("keepalive@openssh.com"); 484 packet_put_char(1); /* boolean: want reply */ 485 packet_send(); 486 /* Insert an empty placeholder to maintain ordering */ 487 client_register_global_confirm(NULL, NULL); 488 } 489 490 /* 491 * Waits until the client can do something (some data becomes available on 492 * one of the file descriptors). 493 */ 494 static void 495 client_wait_until_can_do_something(struct ssh *ssh, 496 fd_set **readsetp, fd_set **writesetp, 497 int *maxfdp, u_int *nallocp, int rekeying) 498 { 499 struct timeval tv, *tvp; 500 int timeout_secs; 501 time_t minwait_secs = 0, server_alive_time = 0, now = monotime(); 502 int ret; 503 504 /* Add any selections by the channel mechanism. */ 505 channel_prepare_select(active_state, readsetp, writesetp, maxfdp, 506 nallocp, &minwait_secs); 507 508 /* channel_prepare_select could have closed the last channel */ 509 if (session_closed && !channel_still_open(ssh) && 510 !packet_have_data_to_write()) { 511 /* clear mask since we did not call select() */ 512 memset(*readsetp, 0, *nallocp); 513 memset(*writesetp, 0, *nallocp); 514 return; 515 } 516 517 FD_SET(connection_in, *readsetp); 518 519 /* Select server connection if have data to write to the server. */ 520 if (packet_have_data_to_write()) 521 FD_SET(connection_out, *writesetp); 522 523 /* 524 * Wait for something to happen. This will suspend the process until 525 * some selected descriptor can be read, written, or has some other 526 * event pending, or a timeout expires. 527 */ 528 529 timeout_secs = INT_MAX; /* we use INT_MAX to mean no timeout */ 530 if (options.server_alive_interval > 0) { 531 timeout_secs = options.server_alive_interval; 532 server_alive_time = now + options.server_alive_interval; 533 } 534 if (options.rekey_interval > 0 && !rekeying) 535 timeout_secs = MINIMUM(timeout_secs, packet_get_rekey_timeout()); 536 set_control_persist_exit_time(ssh); 537 if (control_persist_exit_time > 0) { 538 timeout_secs = MINIMUM(timeout_secs, 539 control_persist_exit_time - now); 540 if (timeout_secs < 0) 541 timeout_secs = 0; 542 } 543 if (minwait_secs != 0) 544 timeout_secs = MINIMUM(timeout_secs, (int)minwait_secs); 545 if (timeout_secs == INT_MAX) 546 tvp = NULL; 547 else { 548 tv.tv_sec = timeout_secs; 549 tv.tv_usec = 0; 550 tvp = &tv; 551 } 552 553 ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp); 554 if (ret < 0) { 555 char buf[100]; 556 557 /* 558 * We have to clear the select masks, because we return. 559 * We have to return, because the mainloop checks for the flags 560 * set by the signal handlers. 561 */ 562 memset(*readsetp, 0, *nallocp); 563 memset(*writesetp, 0, *nallocp); 564 565 if (errno == EINTR) 566 return; 567 /* Note: we might still have data in the buffers. */ 568 snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno)); 569 buffer_append(&stderr_buffer, buf, strlen(buf)); 570 quit_pending = 1; 571 } else if (ret == 0) { 572 /* 573 * Timeout. Could have been either keepalive or rekeying. 574 * Keepalive we check here, rekeying is checked in clientloop. 575 */ 576 if (server_alive_time != 0 && server_alive_time <= monotime()) 577 server_alive_check(); 578 } 579 580 } 581 582 static void 583 client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr) 584 { 585 /* Flush stdout and stderr buffers. */ 586 if (buffer_len(bout) > 0) 587 atomicio(vwrite, fileno(stdout), buffer_ptr(bout), 588 buffer_len(bout)); 589 if (buffer_len(berr) > 0) 590 atomicio(vwrite, fileno(stderr), buffer_ptr(berr), 591 buffer_len(berr)); 592 593 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 594 595 sshbuf_reset(bin); 596 sshbuf_reset(bout); 597 sshbuf_reset(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 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 606 } 607 608 static void 609 client_process_net_input(fd_set *readset) 610 { 611 int len; 612 char buf[8192]; 613 614 /* 615 * Read input from the server, and add any such data to the buffer of 616 * the packet subsystem. 617 */ 618 if (FD_ISSET(connection_in, readset)) { 619 /* Read as much as possible. */ 620 len = read(connection_in, buf, sizeof(buf)); 621 if (len == 0) { 622 /* 623 * Received EOF. The remote host has closed the 624 * connection. 625 */ 626 snprintf(buf, sizeof buf, 627 "Connection to %.300s closed by remote host.\r\n", 628 host); 629 buffer_append(&stderr_buffer, buf, strlen(buf)); 630 quit_pending = 1; 631 return; 632 } 633 /* 634 * There is a kernel bug on Solaris that causes select to 635 * sometimes wake up even though there is no data available. 636 */ 637 if (len < 0 && (errno == EAGAIN || errno == EINTR)) 638 len = 0; 639 640 if (len < 0) { 641 /* 642 * An error has encountered. Perhaps there is a 643 * network problem. 644 */ 645 snprintf(buf, sizeof buf, 646 "Read from remote host %.300s: %.100s\r\n", 647 host, strerror(errno)); 648 buffer_append(&stderr_buffer, buf, strlen(buf)); 649 quit_pending = 1; 650 return; 651 } 652 packet_process_incoming(buf, len); 653 } 654 } 655 656 static void 657 client_status_confirm(struct ssh *ssh, int type, Channel *c, void *ctx) 658 { 659 struct channel_reply_ctx *cr = (struct channel_reply_ctx *)ctx; 660 char errmsg[256]; 661 int tochan; 662 663 /* 664 * If a TTY was explicitly requested, then a failure to allocate 665 * one is fatal. 666 */ 667 if (cr->action == CONFIRM_TTY && 668 (options.request_tty == REQUEST_TTY_FORCE || 669 options.request_tty == REQUEST_TTY_YES)) 670 cr->action = CONFIRM_CLOSE; 671 672 /* XXX supress on mux _client_ quietmode */ 673 tochan = options.log_level >= SYSLOG_LEVEL_ERROR && 674 c->ctl_chan != -1 && c->extended_usage == CHAN_EXTENDED_WRITE; 675 676 if (type == SSH2_MSG_CHANNEL_SUCCESS) { 677 debug2("%s request accepted on channel %d", 678 cr->request_type, c->self); 679 } else if (type == SSH2_MSG_CHANNEL_FAILURE) { 680 if (tochan) { 681 snprintf(errmsg, sizeof(errmsg), 682 "%s request failed\r\n", cr->request_type); 683 } else { 684 snprintf(errmsg, sizeof(errmsg), 685 "%s request failed on channel %d", 686 cr->request_type, c->self); 687 } 688 /* If error occurred on primary session channel, then exit */ 689 if (cr->action == CONFIRM_CLOSE && c->self == session_ident) 690 fatal("%s", errmsg); 691 /* 692 * If error occurred on mux client, append to 693 * their stderr. 694 */ 695 if (tochan) { 696 buffer_append(c->extended, errmsg, strlen(errmsg)); 697 } else 698 error("%s", errmsg); 699 if (cr->action == CONFIRM_TTY) { 700 /* 701 * If a TTY allocation error occurred, then arrange 702 * for the correct TTY to leave raw mode. 703 */ 704 if (c->self == session_ident) 705 leave_raw_mode(0); 706 else 707 mux_tty_alloc_failed(ssh, c); 708 } else if (cr->action == CONFIRM_CLOSE) { 709 chan_read_failed(ssh, c); 710 chan_write_failed(ssh, c); 711 } 712 } 713 free(cr); 714 } 715 716 static void 717 client_abandon_status_confirm(struct ssh *ssh, Channel *c, void *ctx) 718 { 719 free(ctx); 720 } 721 722 void 723 client_expect_confirm(struct ssh *ssh, int id, const char *request, 724 enum confirm_action action) 725 { 726 struct channel_reply_ctx *cr = xcalloc(1, sizeof(*cr)); 727 728 cr->request_type = request; 729 cr->action = action; 730 731 channel_register_status_confirm(ssh, id, client_status_confirm, 732 client_abandon_status_confirm, cr); 733 } 734 735 void 736 client_register_global_confirm(global_confirm_cb *cb, void *ctx) 737 { 738 struct global_confirm *gc, *last_gc; 739 740 /* Coalesce identical callbacks */ 741 last_gc = TAILQ_LAST(&global_confirms, global_confirms); 742 if (last_gc && last_gc->cb == cb && last_gc->ctx == ctx) { 743 if (++last_gc->ref_count >= INT_MAX) 744 fatal("%s: last_gc->ref_count = %d", 745 __func__, last_gc->ref_count); 746 return; 747 } 748 749 gc = xcalloc(1, sizeof(*gc)); 750 gc->cb = cb; 751 gc->ctx = ctx; 752 gc->ref_count = 1; 753 TAILQ_INSERT_TAIL(&global_confirms, gc, entry); 754 } 755 756 static void 757 process_cmdline(struct ssh *ssh) 758 { 759 void (*handler)(int); 760 char *s, *cmd; 761 int ok, delete = 0, local = 0, remote = 0, dynamic = 0; 762 struct Forward fwd; 763 764 memset(&fwd, 0, sizeof(fwd)); 765 766 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 767 handler = signal(SIGINT, SIG_IGN); 768 cmd = s = read_passphrase("\r\nssh> ", RP_ECHO); 769 if (s == NULL) 770 goto out; 771 while (isspace((u_char)*s)) 772 s++; 773 if (*s == '-') 774 s++; /* Skip cmdline '-', if any */ 775 if (*s == '\0') 776 goto out; 777 778 if (*s == 'h' || *s == 'H' || *s == '?') { 779 logit("Commands:"); 780 logit(" -L[bind_address:]port:host:hostport " 781 "Request local forward"); 782 logit(" -R[bind_address:]port:host:hostport " 783 "Request remote forward"); 784 logit(" -D[bind_address:]port " 785 "Request dynamic forward"); 786 logit(" -KL[bind_address:]port " 787 "Cancel local forward"); 788 logit(" -KR[bind_address:]port " 789 "Cancel remote forward"); 790 logit(" -KD[bind_address:]port " 791 "Cancel dynamic forward"); 792 if (!options.permit_local_command) 793 goto out; 794 logit(" !args " 795 "Execute local command"); 796 goto out; 797 } 798 799 if (*s == '!' && options.permit_local_command) { 800 s++; 801 ssh_local_cmd(s); 802 goto out; 803 } 804 805 if (*s == 'K') { 806 delete = 1; 807 s++; 808 } 809 if (*s == 'L') 810 local = 1; 811 else if (*s == 'R') 812 remote = 1; 813 else if (*s == 'D') 814 dynamic = 1; 815 else { 816 logit("Invalid command."); 817 goto out; 818 } 819 820 while (isspace((u_char)*++s)) 821 ; 822 823 /* XXX update list of forwards in options */ 824 if (delete) { 825 /* We pass 1 for dynamicfwd to restrict to 1 or 2 fields. */ 826 if (!parse_forward(&fwd, s, 1, 0)) { 827 logit("Bad forwarding close specification."); 828 goto out; 829 } 830 if (remote) 831 ok = channel_request_rforward_cancel(ssh, &fwd) == 0; 832 else if (dynamic) 833 ok = channel_cancel_lport_listener(ssh, &fwd, 834 0, &options.fwd_opts) > 0; 835 else 836 ok = channel_cancel_lport_listener(ssh, &fwd, 837 CHANNEL_CANCEL_PORT_STATIC, 838 &options.fwd_opts) > 0; 839 if (!ok) { 840 logit("Unknown port forwarding."); 841 goto out; 842 } 843 logit("Canceled forwarding."); 844 } else { 845 if (!parse_forward(&fwd, s, dynamic, remote)) { 846 logit("Bad forwarding specification."); 847 goto out; 848 } 849 if (local || dynamic) { 850 if (!channel_setup_local_fwd_listener(ssh, &fwd, 851 &options.fwd_opts)) { 852 logit("Port forwarding failed."); 853 goto out; 854 } 855 } else { 856 if (channel_request_remote_forwarding(ssh, &fwd) < 0) { 857 logit("Port forwarding failed."); 858 goto out; 859 } 860 } 861 logit("Forwarding port."); 862 } 863 864 out: 865 signal(SIGINT, handler); 866 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 867 free(cmd); 868 free(fwd.listen_host); 869 free(fwd.listen_path); 870 free(fwd.connect_host); 871 free(fwd.connect_path); 872 } 873 874 /* reasons to suppress output of an escape command in help output */ 875 #define SUPPRESS_NEVER 0 /* never suppress, always show */ 876 #define SUPPRESS_MUXCLIENT 1 /* don't show in mux client sessions */ 877 #define SUPPRESS_MUXMASTER 2 /* don't show in mux master sessions */ 878 #define SUPPRESS_SYSLOG 4 /* don't show when logging to syslog */ 879 struct escape_help_text { 880 const char *cmd; 881 const char *text; 882 unsigned int flags; 883 }; 884 static struct escape_help_text esc_txt[] = { 885 {".", "terminate session", SUPPRESS_MUXMASTER}, 886 {".", "terminate connection (and any multiplexed sessions)", 887 SUPPRESS_MUXCLIENT}, 888 {"B", "send a BREAK to the remote system", SUPPRESS_NEVER}, 889 {"C", "open a command line", SUPPRESS_MUXCLIENT}, 890 {"R", "request rekey", SUPPRESS_NEVER}, 891 {"V/v", "decrease/increase verbosity (LogLevel)", SUPPRESS_MUXCLIENT}, 892 {"^Z", "suspend ssh", SUPPRESS_MUXCLIENT}, 893 {"#", "list forwarded connections", SUPPRESS_NEVER}, 894 {"&", "background ssh (when waiting for connections to terminate)", 895 SUPPRESS_MUXCLIENT}, 896 {"?", "this message", SUPPRESS_NEVER}, 897 }; 898 899 static void 900 print_escape_help(Buffer *b, int escape_char, int mux_client, int using_stderr) 901 { 902 unsigned int i, suppress_flags; 903 char string[1024]; 904 905 snprintf(string, sizeof string, "%c?\r\n" 906 "Supported escape sequences:\r\n", escape_char); 907 buffer_append(b, string, strlen(string)); 908 909 suppress_flags = 910 (mux_client ? SUPPRESS_MUXCLIENT : 0) | 911 (mux_client ? 0 : SUPPRESS_MUXMASTER) | 912 (using_stderr ? 0 : SUPPRESS_SYSLOG); 913 914 for (i = 0; i < sizeof(esc_txt)/sizeof(esc_txt[0]); i++) { 915 if (esc_txt[i].flags & suppress_flags) 916 continue; 917 snprintf(string, sizeof string, " %c%-3s - %s\r\n", 918 escape_char, esc_txt[i].cmd, esc_txt[i].text); 919 buffer_append(b, string, strlen(string)); 920 } 921 922 snprintf(string, sizeof string, 923 " %c%c - send the escape character by typing it twice\r\n" 924 "(Note that escapes are only recognized immediately after " 925 "newline.)\r\n", escape_char, escape_char); 926 buffer_append(b, string, strlen(string)); 927 } 928 929 /* 930 * Process the characters one by one. 931 */ 932 static int 933 process_escapes(struct ssh *ssh, Channel *c, 934 Buffer *bin, Buffer *bout, Buffer *berr, 935 char *buf, int len) 936 { 937 char string[1024]; 938 pid_t pid; 939 int bytes = 0; 940 u_int i; 941 u_char ch; 942 char *s; 943 struct escape_filter_ctx *efc = c->filter_ctx == NULL ? 944 NULL : (struct escape_filter_ctx *)c->filter_ctx; 945 946 if (c->filter_ctx == NULL) 947 return 0; 948 949 if (len <= 0) 950 return (0); 951 952 for (i = 0; i < (u_int)len; i++) { 953 /* Get one character at a time. */ 954 ch = buf[i]; 955 956 if (efc->escape_pending) { 957 /* We have previously seen an escape character. */ 958 /* Clear the flag now. */ 959 efc->escape_pending = 0; 960 961 /* Process the escaped character. */ 962 switch (ch) { 963 case '.': 964 /* Terminate the connection. */ 965 snprintf(string, sizeof string, "%c.\r\n", 966 efc->escape_char); 967 buffer_append(berr, string, strlen(string)); 968 969 if (c && c->ctl_chan != -1) { 970 chan_read_failed(ssh, c); 971 chan_write_failed(ssh, c); 972 if (c->detach_user) { 973 c->detach_user(ssh, 974 c->self, NULL); 975 } 976 c->type = SSH_CHANNEL_ABANDONED; 977 buffer_clear(c->input); 978 chan_ibuf_empty(ssh, c); 979 return 0; 980 } else 981 quit_pending = 1; 982 return -1; 983 984 case 'Z' - 64: 985 /* XXX support this for mux clients */ 986 if (c && c->ctl_chan != -1) { 987 char b[16]; 988 noescape: 989 if (ch == 'Z' - 64) 990 snprintf(b, sizeof b, "^Z"); 991 else 992 snprintf(b, sizeof b, "%c", ch); 993 snprintf(string, sizeof string, 994 "%c%s escape not available to " 995 "multiplexed sessions\r\n", 996 efc->escape_char, b); 997 buffer_append(berr, string, 998 strlen(string)); 999 continue; 1000 } 1001 /* Suspend the program. Inform the user */ 1002 snprintf(string, sizeof string, 1003 "%c^Z [suspend ssh]\r\n", efc->escape_char); 1004 buffer_append(berr, string, strlen(string)); 1005 1006 /* Restore terminal modes and suspend. */ 1007 client_suspend_self(bin, bout, berr); 1008 1009 /* We have been continued. */ 1010 continue; 1011 1012 case 'B': 1013 snprintf(string, sizeof string, 1014 "%cB\r\n", efc->escape_char); 1015 buffer_append(berr, string, strlen(string)); 1016 channel_request_start(ssh, c->self, "break", 0); 1017 packet_put_int(1000); 1018 packet_send(); 1019 continue; 1020 1021 case 'R': 1022 if (datafellows & SSH_BUG_NOREKEY) 1023 logit("Server does not " 1024 "support re-keying"); 1025 else 1026 need_rekeying = 1; 1027 continue; 1028 1029 case 'V': 1030 /* FALLTHROUGH */ 1031 case 'v': 1032 if (c && c->ctl_chan != -1) 1033 goto noescape; 1034 if (!log_is_on_stderr()) { 1035 snprintf(string, sizeof string, 1036 "%c%c [Logging to syslog]\r\n", 1037 efc->escape_char, ch); 1038 buffer_append(berr, string, 1039 strlen(string)); 1040 continue; 1041 } 1042 if (ch == 'V' && options.log_level > 1043 SYSLOG_LEVEL_QUIET) 1044 log_change_level(--options.log_level); 1045 if (ch == 'v' && options.log_level < 1046 SYSLOG_LEVEL_DEBUG3) 1047 log_change_level(++options.log_level); 1048 snprintf(string, sizeof string, 1049 "%c%c [LogLevel %s]\r\n", 1050 efc->escape_char, ch, 1051 log_level_name(options.log_level)); 1052 buffer_append(berr, string, strlen(string)); 1053 continue; 1054 1055 case '&': 1056 if (c && c->ctl_chan != -1) 1057 goto noescape; 1058 /* 1059 * Detach the program (continue to serve 1060 * connections, but put in background and no 1061 * more new connections). 1062 */ 1063 /* Restore tty modes. */ 1064 leave_raw_mode( 1065 options.request_tty == REQUEST_TTY_FORCE); 1066 1067 /* Stop listening for new connections. */ 1068 channel_stop_listening(ssh); 1069 1070 snprintf(string, sizeof string, 1071 "%c& [backgrounded]\n", efc->escape_char); 1072 buffer_append(berr, string, strlen(string)); 1073 1074 /* Fork into background. */ 1075 pid = fork(); 1076 if (pid < 0) { 1077 error("fork: %.100s", strerror(errno)); 1078 continue; 1079 } 1080 if (pid != 0) { /* This is the parent. */ 1081 /* The parent just exits. */ 1082 exit(0); 1083 } 1084 /* The child continues serving connections. */ 1085 buffer_append(bin, "\004", 1); 1086 /* fake EOF on stdin */ 1087 return -1; 1088 case '?': 1089 print_escape_help(berr, efc->escape_char, 1090 (c && c->ctl_chan != -1), 1091 log_is_on_stderr()); 1092 continue; 1093 1094 case '#': 1095 snprintf(string, sizeof string, "%c#\r\n", 1096 efc->escape_char); 1097 buffer_append(berr, string, strlen(string)); 1098 s = channel_open_message(ssh); 1099 buffer_append(berr, s, strlen(s)); 1100 free(s); 1101 continue; 1102 1103 case 'C': 1104 if (c && c->ctl_chan != -1) 1105 goto noescape; 1106 process_cmdline(ssh); 1107 continue; 1108 1109 default: 1110 if (ch != efc->escape_char) { 1111 buffer_put_char(bin, efc->escape_char); 1112 bytes++; 1113 } 1114 /* Escaped characters fall through here */ 1115 break; 1116 } 1117 } else { 1118 /* 1119 * The previous character was not an escape char. 1120 * Check if this is an escape. 1121 */ 1122 if (last_was_cr && ch == efc->escape_char) { 1123 /* 1124 * It is. Set the flag and continue to 1125 * next character. 1126 */ 1127 efc->escape_pending = 1; 1128 continue; 1129 } 1130 } 1131 1132 /* 1133 * Normal character. Record whether it was a newline, 1134 * and append it to the buffer. 1135 */ 1136 last_was_cr = (ch == '\r' || ch == '\n'); 1137 buffer_put_char(bin, ch); 1138 bytes++; 1139 } 1140 return bytes; 1141 } 1142 1143 /* 1144 * Get packets from the connection input buffer, and process them as long as 1145 * there are packets available. 1146 * 1147 * Any unknown packets received during the actual 1148 * session cause the session to terminate. This is 1149 * intended to make debugging easier since no 1150 * confirmations are sent. Any compatible protocol 1151 * extensions must be negotiated during the 1152 * preparatory phase. 1153 */ 1154 1155 static void 1156 client_process_buffered_input_packets(void) 1157 { 1158 ssh_dispatch_run_fatal(active_state, DISPATCH_NONBLOCK, &quit_pending); 1159 } 1160 1161 /* scan buf[] for '~' before sending data to the peer */ 1162 1163 /* Helper: allocate a new escape_filter_ctx and fill in its escape char */ 1164 void * 1165 client_new_escape_filter_ctx(int escape_char) 1166 { 1167 struct escape_filter_ctx *ret; 1168 1169 ret = xcalloc(1, sizeof(*ret)); 1170 ret->escape_pending = 0; 1171 ret->escape_char = escape_char; 1172 return (void *)ret; 1173 } 1174 1175 /* Free the escape filter context on channel free */ 1176 void 1177 client_filter_cleanup(struct ssh *ssh, int cid, void *ctx) 1178 { 1179 free(ctx); 1180 } 1181 1182 int 1183 client_simple_escape_filter(struct ssh *ssh, Channel *c, char *buf, int len) 1184 { 1185 if (c->extended_usage != CHAN_EXTENDED_WRITE) 1186 return 0; 1187 1188 return process_escapes(ssh, c, c->input, c->output, c->extended, 1189 buf, len); 1190 } 1191 1192 static void 1193 client_channel_closed(struct ssh *ssh, int id, void *arg) 1194 { 1195 channel_cancel_cleanup(ssh, id); 1196 session_closed = 1; 1197 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1198 } 1199 1200 /* 1201 * Implements the interactive session with the server. This is called after 1202 * the user has been authenticated, and a command has been started on the 1203 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character 1204 * used as an escape character for terminating or suspending the session. 1205 */ 1206 int 1207 client_loop(struct ssh *ssh, int have_pty, int escape_char_arg, 1208 int ssh2_chan_id) 1209 { 1210 fd_set *readset = NULL, *writeset = NULL; 1211 double start_time, total_time; 1212 int r, max_fd = 0, max_fd2 = 0, len; 1213 u_int64_t ibytes, obytes; 1214 u_int nalloc = 0; 1215 char buf[100]; 1216 1217 debug("Entering interactive session."); 1218 1219 if (options.control_master && 1220 !option_clear_or_none(options.control_path)) { 1221 debug("pledge: id"); 1222 if (pledge("stdio rpath wpath cpath unix inet dns recvfd proc exec id tty", 1223 NULL) == -1) 1224 fatal("%s pledge(): %s", __func__, strerror(errno)); 1225 1226 } else if (options.forward_x11 || options.permit_local_command) { 1227 debug("pledge: exec"); 1228 if (pledge("stdio rpath wpath cpath unix inet dns proc exec tty", 1229 NULL) == -1) 1230 fatal("%s pledge(): %s", __func__, strerror(errno)); 1231 1232 } else if (options.update_hostkeys) { 1233 debug("pledge: filesystem full"); 1234 if (pledge("stdio rpath wpath cpath unix inet dns proc tty", 1235 NULL) == -1) 1236 fatal("%s pledge(): %s", __func__, strerror(errno)); 1237 1238 } else if (!option_clear_or_none(options.proxy_command) || 1239 fork_after_authentication_flag) { 1240 debug("pledge: proc"); 1241 if (pledge("stdio cpath unix inet dns proc tty", NULL) == -1) 1242 fatal("%s pledge(): %s", __func__, strerror(errno)); 1243 1244 } else { 1245 debug("pledge: network"); 1246 if (pledge("stdio unix inet dns proc tty", NULL) == -1) 1247 fatal("%s pledge(): %s", __func__, strerror(errno)); 1248 } 1249 1250 start_time = get_current_time(); 1251 1252 /* Initialize variables. */ 1253 last_was_cr = 1; 1254 exit_status = -1; 1255 connection_in = packet_get_connection_in(); 1256 connection_out = packet_get_connection_out(); 1257 max_fd = MAXIMUM(connection_in, connection_out); 1258 1259 quit_pending = 0; 1260 1261 /* Initialize buffers. */ 1262 buffer_init(&stderr_buffer); 1263 1264 client_init_dispatch(); 1265 1266 /* 1267 * Set signal handlers, (e.g. to restore non-blocking mode) 1268 * but don't overwrite SIG_IGN, matches behaviour from rsh(1) 1269 */ 1270 if (signal(SIGHUP, SIG_IGN) != SIG_IGN) 1271 signal(SIGHUP, signal_handler); 1272 if (signal(SIGINT, SIG_IGN) != SIG_IGN) 1273 signal(SIGINT, signal_handler); 1274 if (signal(SIGQUIT, SIG_IGN) != SIG_IGN) 1275 signal(SIGQUIT, signal_handler); 1276 if (signal(SIGTERM, SIG_IGN) != SIG_IGN) 1277 signal(SIGTERM, signal_handler); 1278 signal(SIGWINCH, window_change_handler); 1279 1280 if (have_pty) 1281 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1282 1283 session_ident = ssh2_chan_id; 1284 if (session_ident != -1) { 1285 if (escape_char_arg != SSH_ESCAPECHAR_NONE) { 1286 channel_register_filter(ssh, session_ident, 1287 client_simple_escape_filter, NULL, 1288 client_filter_cleanup, 1289 client_new_escape_filter_ctx( 1290 escape_char_arg)); 1291 } 1292 channel_register_cleanup(ssh, session_ident, 1293 client_channel_closed, 0); 1294 } 1295 1296 /* Main loop of the client for the interactive session mode. */ 1297 while (!quit_pending) { 1298 1299 /* Process buffered packets sent by the server. */ 1300 client_process_buffered_input_packets(); 1301 1302 if (session_closed && !channel_still_open(ssh)) 1303 break; 1304 1305 if (ssh_packet_is_rekeying(ssh)) { 1306 debug("rekeying in progress"); 1307 } else if (need_rekeying) { 1308 /* manual rekey request */ 1309 debug("need rekeying"); 1310 if ((r = kex_start_rekex(ssh)) != 0) 1311 fatal("%s: kex_start_rekex: %s", __func__, 1312 ssh_err(r)); 1313 need_rekeying = 0; 1314 } else { 1315 /* 1316 * Make packets from buffered channel data, and 1317 * enqueue them for sending to the server. 1318 */ 1319 if (packet_not_very_much_data_to_write()) 1320 channel_output_poll(ssh); 1321 1322 /* 1323 * Check if the window size has changed, and buffer a 1324 * message about it to the server if so. 1325 */ 1326 client_check_window_change(ssh); 1327 1328 if (quit_pending) 1329 break; 1330 } 1331 /* 1332 * Wait until we have something to do (something becomes 1333 * available on one of the descriptors). 1334 */ 1335 max_fd2 = max_fd; 1336 client_wait_until_can_do_something(ssh, &readset, &writeset, 1337 &max_fd2, &nalloc, ssh_packet_is_rekeying(ssh)); 1338 1339 if (quit_pending) 1340 break; 1341 1342 /* Do channel operations unless rekeying in progress. */ 1343 if (!ssh_packet_is_rekeying(ssh)) 1344 channel_after_select(ssh, readset, writeset); 1345 1346 /* Buffer input from the connection. */ 1347 client_process_net_input(readset); 1348 1349 if (quit_pending) 1350 break; 1351 1352 /* 1353 * Send as much buffered packet data as possible to the 1354 * sender. 1355 */ 1356 if (FD_ISSET(connection_out, writeset)) 1357 packet_write_poll(); 1358 1359 /* 1360 * If we are a backgrounded control master, and the 1361 * timeout has expired without any active client 1362 * connections, then quit. 1363 */ 1364 if (control_persist_exit_time > 0) { 1365 if (monotime() >= control_persist_exit_time) { 1366 debug("ControlPersist timeout expired"); 1367 break; 1368 } 1369 } 1370 } 1371 free(readset); 1372 free(writeset); 1373 1374 /* Terminate the session. */ 1375 1376 /* Stop watching for window change. */ 1377 signal(SIGWINCH, SIG_DFL); 1378 1379 packet_start(SSH2_MSG_DISCONNECT); 1380 packet_put_int(SSH2_DISCONNECT_BY_APPLICATION); 1381 packet_put_cstring("disconnected by user"); 1382 packet_put_cstring(""); /* language tag */ 1383 packet_send(); 1384 packet_write_wait(); 1385 1386 channel_free_all(ssh); 1387 1388 if (have_pty) 1389 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1390 1391 /* restore blocking io */ 1392 if (!isatty(fileno(stdin))) 1393 unset_nonblock(fileno(stdin)); 1394 if (!isatty(fileno(stdout))) 1395 unset_nonblock(fileno(stdout)); 1396 if (!isatty(fileno(stderr))) 1397 unset_nonblock(fileno(stderr)); 1398 1399 /* 1400 * If there was no shell or command requested, there will be no remote 1401 * exit status to be returned. In that case, clear error code if the 1402 * connection was deliberately terminated at this end. 1403 */ 1404 if (no_shell_flag && received_signal == SIGTERM) { 1405 received_signal = 0; 1406 exit_status = 0; 1407 } 1408 1409 if (received_signal) { 1410 verbose("Killed by signal %d.", (int) received_signal); 1411 cleanup_exit(0); 1412 } 1413 1414 /* 1415 * In interactive mode (with pseudo tty) display a message indicating 1416 * that the connection has been closed. 1417 */ 1418 if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) { 1419 snprintf(buf, sizeof buf, 1420 "Connection to %.64s closed.\r\n", host); 1421 buffer_append(&stderr_buffer, buf, strlen(buf)); 1422 } 1423 1424 /* Output any buffered data for stderr. */ 1425 if (buffer_len(&stderr_buffer) > 0) { 1426 len = atomicio(vwrite, fileno(stderr), 1427 buffer_ptr(&stderr_buffer), buffer_len(&stderr_buffer)); 1428 if (len < 0 || (u_int)len != buffer_len(&stderr_buffer)) 1429 error("Write failed flushing stderr buffer."); 1430 else 1431 buffer_consume(&stderr_buffer, len); 1432 } 1433 1434 /* Clear and free any buffers. */ 1435 explicit_bzero(buf, sizeof(buf)); 1436 buffer_free(&stderr_buffer); 1437 1438 /* Report bytes transferred, and transfer rates. */ 1439 total_time = get_current_time() - start_time; 1440 packet_get_bytes(&ibytes, &obytes); 1441 verbose("Transferred: sent %llu, received %llu bytes, in %.1f seconds", 1442 (unsigned long long)obytes, (unsigned long long)ibytes, total_time); 1443 if (total_time > 0) 1444 verbose("Bytes per second: sent %.1f, received %.1f", 1445 obytes / total_time, ibytes / total_time); 1446 /* Return the exit status of the program. */ 1447 debug("Exit status %d", exit_status); 1448 return exit_status; 1449 } 1450 1451 /*********/ 1452 1453 static Channel * 1454 client_request_forwarded_tcpip(struct ssh *ssh, const char *request_type, 1455 int rchan, u_int rwindow, u_int rmaxpack) 1456 { 1457 Channel *c = NULL; 1458 struct sshbuf *b = NULL; 1459 char *listen_address, *originator_address; 1460 u_short listen_port, originator_port; 1461 int r; 1462 1463 /* Get rest of the packet */ 1464 listen_address = packet_get_string(NULL); 1465 listen_port = packet_get_int(); 1466 originator_address = packet_get_string(NULL); 1467 originator_port = packet_get_int(); 1468 packet_check_eom(); 1469 1470 debug("%s: listen %s port %d, originator %s port %d", __func__, 1471 listen_address, listen_port, originator_address, originator_port); 1472 1473 c = channel_connect_by_listen_address(ssh, listen_address, listen_port, 1474 "forwarded-tcpip", originator_address); 1475 1476 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) { 1477 if ((b = sshbuf_new()) == NULL) { 1478 error("%s: alloc reply", __func__); 1479 goto out; 1480 } 1481 /* reconstruct and send to muxclient */ 1482 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 1483 (r = sshbuf_put_u8(b, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1484 (r = sshbuf_put_cstring(b, request_type)) != 0 || 1485 (r = sshbuf_put_u32(b, rchan)) != 0 || 1486 (r = sshbuf_put_u32(b, rwindow)) != 0 || 1487 (r = sshbuf_put_u32(b, rmaxpack)) != 0 || 1488 (r = sshbuf_put_cstring(b, listen_address)) != 0 || 1489 (r = sshbuf_put_u32(b, listen_port)) != 0 || 1490 (r = sshbuf_put_cstring(b, originator_address)) != 0 || 1491 (r = sshbuf_put_u32(b, originator_port)) != 0 || 1492 (r = sshbuf_put_stringb(c->output, b)) != 0) { 1493 error("%s: compose for muxclient %s", __func__, 1494 ssh_err(r)); 1495 goto out; 1496 } 1497 } 1498 1499 out: 1500 sshbuf_free(b); 1501 free(originator_address); 1502 free(listen_address); 1503 return c; 1504 } 1505 1506 static Channel * 1507 client_request_forwarded_streamlocal(struct ssh *ssh, 1508 const char *request_type, int rchan) 1509 { 1510 Channel *c = NULL; 1511 char *listen_path; 1512 1513 /* Get the remote path. */ 1514 listen_path = packet_get_string(NULL); 1515 /* XXX: Skip reserved field for now. */ 1516 if (packet_get_string_ptr(NULL) == NULL) 1517 fatal("%s: packet_get_string_ptr failed", __func__); 1518 packet_check_eom(); 1519 1520 debug("%s: %s", __func__, listen_path); 1521 1522 c = channel_connect_by_listen_path(ssh, listen_path, 1523 "forwarded-streamlocal@openssh.com", "forwarded-streamlocal"); 1524 free(listen_path); 1525 return c; 1526 } 1527 1528 static Channel * 1529 client_request_x11(struct ssh *ssh, const char *request_type, int rchan) 1530 { 1531 Channel *c = NULL; 1532 char *originator; 1533 u_short originator_port; 1534 int sock; 1535 1536 if (!options.forward_x11) { 1537 error("Warning: ssh server tried X11 forwarding."); 1538 error("Warning: this is probably a break-in attempt by a " 1539 "malicious server."); 1540 return NULL; 1541 } 1542 if (x11_refuse_time != 0 && (u_int)monotime() >= x11_refuse_time) { 1543 verbose("Rejected X11 connection after ForwardX11Timeout " 1544 "expired"); 1545 return NULL; 1546 } 1547 originator = packet_get_string(NULL); 1548 if (datafellows & SSH_BUG_X11FWD) { 1549 debug2("buggy server: x11 request w/o originator_port"); 1550 originator_port = 0; 1551 } else { 1552 originator_port = packet_get_int(); 1553 } 1554 packet_check_eom(); 1555 /* XXX check permission */ 1556 debug("client_request_x11: request from %s %d", originator, 1557 originator_port); 1558 free(originator); 1559 sock = x11_connect_display(ssh); 1560 if (sock < 0) 1561 return NULL; 1562 c = channel_new(ssh, "x11", 1563 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1564 CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); 1565 c->force_drain = 1; 1566 return c; 1567 } 1568 1569 static Channel * 1570 client_request_agent(struct ssh *ssh, const char *request_type, int rchan) 1571 { 1572 Channel *c = NULL; 1573 int r, sock; 1574 1575 if (!options.forward_agent) { 1576 error("Warning: ssh server tried agent forwarding."); 1577 error("Warning: this is probably a break-in attempt by a " 1578 "malicious server."); 1579 return NULL; 1580 } 1581 if ((r = ssh_get_authentication_socket(&sock)) != 0) { 1582 if (r != SSH_ERR_AGENT_NOT_PRESENT) 1583 debug("%s: ssh_get_authentication_socket: %s", 1584 __func__, ssh_err(r)); 1585 return NULL; 1586 } 1587 c = channel_new(ssh, "authentication agent connection", 1588 SSH_CHANNEL_OPEN, sock, sock, -1, 1589 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, 1590 "authentication agent connection", 1); 1591 c->force_drain = 1; 1592 return c; 1593 } 1594 1595 int 1596 client_request_tun_fwd(struct ssh *ssh, int tun_mode, 1597 int local_tun, int remote_tun) 1598 { 1599 Channel *c; 1600 int fd; 1601 1602 if (tun_mode == SSH_TUNMODE_NO) 1603 return 0; 1604 1605 debug("Requesting tun unit %d in mode %d", local_tun, tun_mode); 1606 1607 /* Open local tunnel device */ 1608 if ((fd = tun_open(local_tun, tun_mode)) == -1) { 1609 error("Tunnel device open failed."); 1610 return -1; 1611 } 1612 1613 c = channel_new(ssh, "tun", SSH_CHANNEL_OPENING, fd, fd, -1, 1614 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1); 1615 c->datagram = 1; 1616 1617 packet_start(SSH2_MSG_CHANNEL_OPEN); 1618 packet_put_cstring("tun@openssh.com"); 1619 packet_put_int(c->self); 1620 packet_put_int(c->local_window_max); 1621 packet_put_int(c->local_maxpacket); 1622 packet_put_int(tun_mode); 1623 packet_put_int(remote_tun); 1624 packet_send(); 1625 1626 return 0; 1627 } 1628 1629 /* XXXX move to generic input handler */ 1630 static int 1631 client_input_channel_open(int type, u_int32_t seq, struct ssh *ssh) 1632 { 1633 Channel *c = NULL; 1634 char *ctype; 1635 int rchan; 1636 u_int rmaxpack, rwindow, len; 1637 1638 ctype = packet_get_string(&len); 1639 rchan = packet_get_int(); 1640 rwindow = packet_get_int(); 1641 rmaxpack = packet_get_int(); 1642 1643 debug("client_input_channel_open: ctype %s rchan %d win %d max %d", 1644 ctype, rchan, rwindow, rmaxpack); 1645 1646 if (strcmp(ctype, "forwarded-tcpip") == 0) { 1647 c = client_request_forwarded_tcpip(ssh, ctype, rchan, rwindow, 1648 rmaxpack); 1649 } else if (strcmp(ctype, "forwarded-streamlocal@openssh.com") == 0) { 1650 c = client_request_forwarded_streamlocal(ssh, ctype, rchan); 1651 } else if (strcmp(ctype, "x11") == 0) { 1652 c = client_request_x11(ssh, ctype, rchan); 1653 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) { 1654 c = client_request_agent(ssh, ctype, rchan); 1655 } 1656 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) { 1657 debug3("proxied to downstream: %s", ctype); 1658 } else if (c != NULL) { 1659 debug("confirm %s", ctype); 1660 c->remote_id = rchan; 1661 c->have_remote_id = 1; 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(ssh, 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(ssh, c); 1712 } else if (strcmp(rtype, "exit-status") == 0) { 1713 exitval = packet_get_int(); 1714 if (c->ctl_chan != -1) { 1715 mux_exit_message(ssh, 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 if (!c->have_remote_id) 1730 fatal("%s: channel %d: no remote_id", 1731 __func__, c->self); 1732 packet_start(success ? 1733 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE); 1734 packet_put_int(c->remote_id); 1735 packet_send(); 1736 } 1737 free(rtype); 1738 return 0; 1739 } 1740 1741 struct hostkeys_update_ctx { 1742 /* The hostname and (optionally) IP address string for the server */ 1743 char *host_str, *ip_str; 1744 1745 /* 1746 * Keys received from the server and a flag for each indicating 1747 * whether they already exist in known_hosts. 1748 * keys_seen is filled in by hostkeys_find() and later (for new 1749 * keys) by client_global_hostkeys_private_confirm(). 1750 */ 1751 struct sshkey **keys; 1752 int *keys_seen; 1753 size_t nkeys, nnew; 1754 1755 /* 1756 * Keys that are in known_hosts, but were not present in the update 1757 * from the server (i.e. scheduled to be deleted). 1758 * Filled in by hostkeys_find(). 1759 */ 1760 struct sshkey **old_keys; 1761 size_t nold; 1762 }; 1763 1764 static void 1765 hostkeys_update_ctx_free(struct hostkeys_update_ctx *ctx) 1766 { 1767 size_t i; 1768 1769 if (ctx == NULL) 1770 return; 1771 for (i = 0; i < ctx->nkeys; i++) 1772 sshkey_free(ctx->keys[i]); 1773 free(ctx->keys); 1774 free(ctx->keys_seen); 1775 for (i = 0; i < ctx->nold; i++) 1776 sshkey_free(ctx->old_keys[i]); 1777 free(ctx->old_keys); 1778 free(ctx->host_str); 1779 free(ctx->ip_str); 1780 free(ctx); 1781 } 1782 1783 static int 1784 hostkeys_find(struct hostkey_foreach_line *l, void *_ctx) 1785 { 1786 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 1787 size_t i; 1788 struct sshkey **tmp; 1789 1790 if (l->status != HKF_STATUS_MATCHED || l->key == NULL) 1791 return 0; 1792 1793 /* Mark off keys we've already seen for this host */ 1794 for (i = 0; i < ctx->nkeys; i++) { 1795 if (sshkey_equal(l->key, ctx->keys[i])) { 1796 debug3("%s: found %s key at %s:%ld", __func__, 1797 sshkey_ssh_name(ctx->keys[i]), l->path, l->linenum); 1798 ctx->keys_seen[i] = 1; 1799 return 0; 1800 } 1801 } 1802 /* This line contained a key that not offered by the server */ 1803 debug3("%s: deprecated %s key at %s:%ld", __func__, 1804 sshkey_ssh_name(l->key), l->path, l->linenum); 1805 if ((tmp = recallocarray(ctx->old_keys, ctx->nold, ctx->nold + 1, 1806 sizeof(*ctx->old_keys))) == NULL) 1807 fatal("%s: recallocarray failed nold = %zu", 1808 __func__, ctx->nold); 1809 ctx->old_keys = tmp; 1810 ctx->old_keys[ctx->nold++] = l->key; 1811 l->key = NULL; 1812 1813 return 0; 1814 } 1815 1816 static void 1817 update_known_hosts(struct hostkeys_update_ctx *ctx) 1818 { 1819 int r, was_raw = 0; 1820 int loglevel = options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK ? 1821 SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_VERBOSE; 1822 char *fp, *response; 1823 size_t i; 1824 1825 for (i = 0; i < ctx->nkeys; i++) { 1826 if (ctx->keys_seen[i] != 2) 1827 continue; 1828 if ((fp = sshkey_fingerprint(ctx->keys[i], 1829 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 1830 fatal("%s: sshkey_fingerprint failed", __func__); 1831 do_log2(loglevel, "Learned new hostkey: %s %s", 1832 sshkey_type(ctx->keys[i]), fp); 1833 free(fp); 1834 } 1835 for (i = 0; i < ctx->nold; i++) { 1836 if ((fp = sshkey_fingerprint(ctx->old_keys[i], 1837 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 1838 fatal("%s: sshkey_fingerprint failed", __func__); 1839 do_log2(loglevel, "Deprecating obsolete hostkey: %s %s", 1840 sshkey_type(ctx->old_keys[i]), fp); 1841 free(fp); 1842 } 1843 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) { 1844 if (get_saved_tio() != NULL) { 1845 leave_raw_mode(1); 1846 was_raw = 1; 1847 } 1848 response = NULL; 1849 for (i = 0; !quit_pending && i < 3; i++) { 1850 free(response); 1851 response = read_passphrase("Accept updated hostkeys? " 1852 "(yes/no): ", RP_ECHO); 1853 if (strcasecmp(response, "yes") == 0) 1854 break; 1855 else if (quit_pending || response == NULL || 1856 strcasecmp(response, "no") == 0) { 1857 options.update_hostkeys = 0; 1858 break; 1859 } else { 1860 do_log2(loglevel, "Please enter " 1861 "\"yes\" or \"no\""); 1862 } 1863 } 1864 if (quit_pending || i >= 3 || response == NULL) 1865 options.update_hostkeys = 0; 1866 free(response); 1867 if (was_raw) 1868 enter_raw_mode(1); 1869 } 1870 1871 /* 1872 * Now that all the keys are verified, we can go ahead and replace 1873 * them in known_hosts (assuming SSH_UPDATE_HOSTKEYS_ASK didn't 1874 * cancel the operation). 1875 */ 1876 if (options.update_hostkeys != 0 && 1877 (r = hostfile_replace_entries(options.user_hostfiles[0], 1878 ctx->host_str, ctx->ip_str, ctx->keys, ctx->nkeys, 1879 options.hash_known_hosts, 0, 1880 options.fingerprint_hash)) != 0) 1881 error("%s: hostfile_replace_entries failed: %s", 1882 __func__, ssh_err(r)); 1883 } 1884 1885 static void 1886 client_global_hostkeys_private_confirm(struct ssh *ssh, int type, 1887 u_int32_t seq, void *_ctx) 1888 { 1889 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 1890 size_t i, ndone; 1891 struct sshbuf *signdata; 1892 int r; 1893 const u_char *sig; 1894 size_t siglen; 1895 1896 if (ctx->nnew == 0) 1897 fatal("%s: ctx->nnew == 0", __func__); /* sanity */ 1898 if (type != SSH2_MSG_REQUEST_SUCCESS) { 1899 error("Server failed to confirm ownership of " 1900 "private host keys"); 1901 hostkeys_update_ctx_free(ctx); 1902 return; 1903 } 1904 if ((signdata = sshbuf_new()) == NULL) 1905 fatal("%s: sshbuf_new failed", __func__); 1906 /* Don't want to accidentally accept an unbound signature */ 1907 if (ssh->kex->session_id_len == 0) 1908 fatal("%s: ssh->kex->session_id_len == 0", __func__); 1909 /* 1910 * Expect a signature for each of the ctx->nnew private keys we 1911 * haven't seen before. They will be in the same order as the 1912 * ctx->keys where the corresponding ctx->keys_seen[i] == 0. 1913 */ 1914 for (ndone = i = 0; i < ctx->nkeys; i++) { 1915 if (ctx->keys_seen[i]) 1916 continue; 1917 /* Prepare data to be signed: session ID, unique string, key */ 1918 sshbuf_reset(signdata); 1919 if ( (r = sshbuf_put_cstring(signdata, 1920 "hostkeys-prove-00@openssh.com")) != 0 || 1921 (r = sshbuf_put_string(signdata, ssh->kex->session_id, 1922 ssh->kex->session_id_len)) != 0 || 1923 (r = sshkey_puts(ctx->keys[i], signdata)) != 0) 1924 fatal("%s: failed to prepare signature: %s", 1925 __func__, ssh_err(r)); 1926 /* Extract and verify signature */ 1927 if ((r = sshpkt_get_string_direct(ssh, &sig, &siglen)) != 0) { 1928 error("%s: couldn't parse message: %s", 1929 __func__, ssh_err(r)); 1930 goto out; 1931 } 1932 if ((r = sshkey_verify(ctx->keys[i], sig, siglen, 1933 sshbuf_ptr(signdata), sshbuf_len(signdata), 0)) != 0) { 1934 error("%s: server gave bad signature for %s key %zu", 1935 __func__, sshkey_type(ctx->keys[i]), i); 1936 goto out; 1937 } 1938 /* Key is good. Mark it as 'seen' */ 1939 ctx->keys_seen[i] = 2; 1940 ndone++; 1941 } 1942 if (ndone != ctx->nnew) 1943 fatal("%s: ndone != ctx->nnew (%zu / %zu)", __func__, 1944 ndone, ctx->nnew); /* Shouldn't happen */ 1945 ssh_packet_check_eom(ssh); 1946 1947 /* Make the edits to known_hosts */ 1948 update_known_hosts(ctx); 1949 out: 1950 hostkeys_update_ctx_free(ctx); 1951 } 1952 1953 /* 1954 * Returns non-zero if the key is accepted by HostkeyAlgorithms. 1955 * Made slightly less trivial by the multiple RSA signature algorithm names. 1956 */ 1957 static int 1958 key_accepted_by_hostkeyalgs(const struct sshkey *key) 1959 { 1960 const char *ktype = sshkey_ssh_name(key); 1961 const char *hostkeyalgs = options.hostkeyalgorithms != NULL ? 1962 options.hostkeyalgorithms : KEX_DEFAULT_PK_ALG; 1963 1964 if (key == NULL || key->type == KEY_UNSPEC) 1965 return 0; 1966 if (key->type == KEY_RSA && 1967 (match_pattern_list("rsa-sha2-256", hostkeyalgs, 0) == 1 || 1968 match_pattern_list("rsa-sha2-512", hostkeyalgs, 0) == 1)) 1969 return 1; 1970 return match_pattern_list(ktype, hostkeyalgs, 0) == 1; 1971 } 1972 1973 /* 1974 * Handle hostkeys-00@openssh.com global request to inform the client of all 1975 * the server's hostkeys. The keys are checked against the user's 1976 * HostkeyAlgorithms preference before they are accepted. 1977 */ 1978 static int 1979 client_input_hostkeys(void) 1980 { 1981 struct ssh *ssh = active_state; /* XXX */ 1982 const u_char *blob = NULL; 1983 size_t i, len = 0; 1984 struct sshbuf *buf = NULL; 1985 struct sshkey *key = NULL, **tmp; 1986 int r; 1987 char *fp; 1988 static int hostkeys_seen = 0; /* XXX use struct ssh */ 1989 extern struct sockaddr_storage hostaddr; /* XXX from ssh.c */ 1990 struct hostkeys_update_ctx *ctx = NULL; 1991 1992 if (hostkeys_seen) 1993 fatal("%s: server already sent hostkeys", __func__); 1994 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK && 1995 options.batch_mode) 1996 return 1; /* won't ask in batchmode, so don't even try */ 1997 if (!options.update_hostkeys || options.num_user_hostfiles <= 0) 1998 return 1; 1999 2000 ctx = xcalloc(1, sizeof(*ctx)); 2001 while (ssh_packet_remaining(ssh) > 0) { 2002 sshkey_free(key); 2003 key = NULL; 2004 if ((r = sshpkt_get_string_direct(ssh, &blob, &len)) != 0) { 2005 error("%s: couldn't parse message: %s", 2006 __func__, ssh_err(r)); 2007 goto out; 2008 } 2009 if ((r = sshkey_from_blob(blob, len, &key)) != 0) { 2010 error("%s: parse key: %s", __func__, ssh_err(r)); 2011 goto out; 2012 } 2013 fp = sshkey_fingerprint(key, options.fingerprint_hash, 2014 SSH_FP_DEFAULT); 2015 debug3("%s: received %s key %s", __func__, 2016 sshkey_type(key), fp); 2017 free(fp); 2018 2019 if (!key_accepted_by_hostkeyalgs(key)) { 2020 debug3("%s: %s key not permitted by HostkeyAlgorithms", 2021 __func__, sshkey_ssh_name(key)); 2022 continue; 2023 } 2024 /* Skip certs */ 2025 if (sshkey_is_cert(key)) { 2026 debug3("%s: %s key is a certificate; skipping", 2027 __func__, sshkey_ssh_name(key)); 2028 continue; 2029 } 2030 /* Ensure keys are unique */ 2031 for (i = 0; i < ctx->nkeys; i++) { 2032 if (sshkey_equal(key, ctx->keys[i])) { 2033 error("%s: received duplicated %s host key", 2034 __func__, sshkey_ssh_name(key)); 2035 goto out; 2036 } 2037 } 2038 /* Key is good, record it */ 2039 if ((tmp = recallocarray(ctx->keys, ctx->nkeys, ctx->nkeys + 1, 2040 sizeof(*ctx->keys))) == NULL) 2041 fatal("%s: recallocarray failed nkeys = %zu", 2042 __func__, ctx->nkeys); 2043 ctx->keys = tmp; 2044 ctx->keys[ctx->nkeys++] = key; 2045 key = NULL; 2046 } 2047 2048 if (ctx->nkeys == 0) { 2049 debug("%s: server sent no hostkeys", __func__); 2050 goto out; 2051 } 2052 2053 if ((ctx->keys_seen = calloc(ctx->nkeys, 2054 sizeof(*ctx->keys_seen))) == NULL) 2055 fatal("%s: calloc failed", __func__); 2056 2057 get_hostfile_hostname_ipaddr(host, 2058 options.check_host_ip ? (struct sockaddr *)&hostaddr : NULL, 2059 options.port, &ctx->host_str, 2060 options.check_host_ip ? &ctx->ip_str : NULL); 2061 2062 /* Find which keys we already know about. */ 2063 if ((r = hostkeys_foreach(options.user_hostfiles[0], hostkeys_find, 2064 ctx, ctx->host_str, ctx->ip_str, 2065 HKF_WANT_PARSE_KEY|HKF_WANT_MATCH)) != 0) { 2066 error("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r)); 2067 goto out; 2068 } 2069 2070 /* Figure out if we have any new keys to add */ 2071 ctx->nnew = 0; 2072 for (i = 0; i < ctx->nkeys; i++) { 2073 if (!ctx->keys_seen[i]) 2074 ctx->nnew++; 2075 } 2076 2077 debug3("%s: %zu keys from server: %zu new, %zu retained. %zu to remove", 2078 __func__, ctx->nkeys, ctx->nnew, ctx->nkeys - ctx->nnew, ctx->nold); 2079 2080 if (ctx->nnew == 0 && ctx->nold != 0) { 2081 /* We have some keys to remove. Just do it. */ 2082 update_known_hosts(ctx); 2083 } else if (ctx->nnew != 0) { 2084 /* 2085 * We have received hitherto-unseen keys from the server. 2086 * Ask the server to confirm ownership of the private halves. 2087 */ 2088 debug3("%s: asking server to prove ownership for %zu keys", 2089 __func__, ctx->nnew); 2090 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 2091 (r = sshpkt_put_cstring(ssh, 2092 "hostkeys-prove-00@openssh.com")) != 0 || 2093 (r = sshpkt_put_u8(ssh, 1)) != 0) /* bool: want reply */ 2094 fatal("%s: cannot prepare packet: %s", 2095 __func__, ssh_err(r)); 2096 if ((buf = sshbuf_new()) == NULL) 2097 fatal("%s: sshbuf_new", __func__); 2098 for (i = 0; i < ctx->nkeys; i++) { 2099 if (ctx->keys_seen[i]) 2100 continue; 2101 sshbuf_reset(buf); 2102 if ((r = sshkey_putb(ctx->keys[i], buf)) != 0) 2103 fatal("%s: sshkey_putb: %s", 2104 __func__, ssh_err(r)); 2105 if ((r = sshpkt_put_stringb(ssh, buf)) != 0) 2106 fatal("%s: sshpkt_put_string: %s", 2107 __func__, ssh_err(r)); 2108 } 2109 if ((r = sshpkt_send(ssh)) != 0) 2110 fatal("%s: sshpkt_send: %s", __func__, ssh_err(r)); 2111 client_register_global_confirm( 2112 client_global_hostkeys_private_confirm, ctx); 2113 ctx = NULL; /* will be freed in callback */ 2114 } 2115 2116 /* Success */ 2117 out: 2118 hostkeys_update_ctx_free(ctx); 2119 sshkey_free(key); 2120 sshbuf_free(buf); 2121 /* 2122 * NB. Return success for all cases. The server doesn't need to know 2123 * what the client does with its hosts file. 2124 */ 2125 return 1; 2126 } 2127 2128 static int 2129 client_input_global_request(int type, u_int32_t seq, struct ssh *ssh) 2130 { 2131 char *rtype; 2132 int want_reply; 2133 int success = 0; 2134 2135 rtype = packet_get_cstring(NULL); 2136 want_reply = packet_get_char(); 2137 debug("client_input_global_request: rtype %s want_reply %d", 2138 rtype, want_reply); 2139 if (strcmp(rtype, "hostkeys-00@openssh.com") == 0) 2140 success = client_input_hostkeys(); 2141 if (want_reply) { 2142 packet_start(success ? 2143 SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE); 2144 packet_send(); 2145 packet_write_wait(); 2146 } 2147 free(rtype); 2148 return 0; 2149 } 2150 2151 void 2152 client_session2_setup(struct ssh *ssh, int id, int want_tty, int want_subsystem, 2153 const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env) 2154 { 2155 int len; 2156 Channel *c = NULL; 2157 2158 debug2("%s: id %d", __func__, id); 2159 2160 if ((c = channel_lookup(ssh, id)) == NULL) 2161 fatal("%s: channel %d: unknown channel", __func__, id); 2162 2163 packet_set_interactive(want_tty, 2164 options.ip_qos_interactive, options.ip_qos_bulk); 2165 2166 if (want_tty) { 2167 struct winsize ws; 2168 2169 /* Store window size in the packet. */ 2170 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0) 2171 memset(&ws, 0, sizeof(ws)); 2172 2173 channel_request_start(ssh, id, "pty-req", 1); 2174 client_expect_confirm(ssh, id, "PTY allocation", CONFIRM_TTY); 2175 packet_put_cstring(term != NULL ? term : ""); 2176 packet_put_int((u_int)ws.ws_col); 2177 packet_put_int((u_int)ws.ws_row); 2178 packet_put_int((u_int)ws.ws_xpixel); 2179 packet_put_int((u_int)ws.ws_ypixel); 2180 if (tiop == NULL) 2181 tiop = get_saved_tio(); 2182 tty_make_modes(-1, tiop); 2183 packet_send(); 2184 /* XXX wait for reply */ 2185 c->client_tty = 1; 2186 } 2187 2188 /* Transfer any environment variables from client to server */ 2189 if (options.num_send_env != 0 && env != NULL) { 2190 int i, j, matched; 2191 char *name, *val; 2192 2193 debug("Sending environment."); 2194 for (i = 0; env[i] != NULL; i++) { 2195 /* Split */ 2196 name = xstrdup(env[i]); 2197 if ((val = strchr(name, '=')) == NULL) { 2198 free(name); 2199 continue; 2200 } 2201 *val++ = '\0'; 2202 2203 matched = 0; 2204 for (j = 0; j < options.num_send_env; j++) { 2205 if (match_pattern(name, options.send_env[j])) { 2206 matched = 1; 2207 break; 2208 } 2209 } 2210 if (!matched) { 2211 debug3("Ignored env %s", name); 2212 free(name); 2213 continue; 2214 } 2215 2216 debug("Sending env %s = %s", name, val); 2217 channel_request_start(ssh, id, "env", 0); 2218 packet_put_cstring(name); 2219 packet_put_cstring(val); 2220 packet_send(); 2221 free(name); 2222 } 2223 } 2224 2225 len = buffer_len(cmd); 2226 if (len > 0) { 2227 if (len > 900) 2228 len = 900; 2229 if (want_subsystem) { 2230 debug("Sending subsystem: %.*s", 2231 len, (u_char*)buffer_ptr(cmd)); 2232 channel_request_start(ssh, id, "subsystem", 1); 2233 client_expect_confirm(ssh, id, "subsystem", 2234 CONFIRM_CLOSE); 2235 } else { 2236 debug("Sending command: %.*s", 2237 len, (u_char*)buffer_ptr(cmd)); 2238 channel_request_start(ssh, id, "exec", 1); 2239 client_expect_confirm(ssh, id, "exec", CONFIRM_CLOSE); 2240 } 2241 packet_put_string(buffer_ptr(cmd), buffer_len(cmd)); 2242 packet_send(); 2243 } else { 2244 channel_request_start(ssh, id, "shell", 1); 2245 client_expect_confirm(ssh, id, "shell", CONFIRM_CLOSE); 2246 packet_send(); 2247 } 2248 } 2249 2250 static void 2251 client_init_dispatch(void) 2252 { 2253 dispatch_init(&dispatch_protocol_error); 2254 2255 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); 2256 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); 2257 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); 2258 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); 2259 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open); 2260 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 2261 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 2262 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req); 2263 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); 2264 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm); 2265 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm); 2266 dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request); 2267 2268 /* rekeying */ 2269 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); 2270 2271 /* global request reply messages */ 2272 dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply); 2273 dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply); 2274 } 2275 2276 void 2277 client_stop_mux(void) 2278 { 2279 if (options.control_path != NULL && muxserver_sock != -1) 2280 unlink(options.control_path); 2281 /* 2282 * If we are in persist mode, or don't have a shell, signal that we 2283 * should close when all active channels are closed. 2284 */ 2285 if (options.control_persist || no_shell_flag) { 2286 session_closed = 1; 2287 setproctitle("[stopped mux]"); 2288 } 2289 } 2290 2291 /* client specific fatal cleanup */ 2292 void 2293 cleanup_exit(int i) 2294 { 2295 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 2296 leave_non_blocking(); 2297 if (options.control_path != NULL && muxserver_sock != -1) 2298 unlink(options.control_path); 2299 ssh_kill_proxy_command(); 2300 _exit(i); 2301 } 2302