1 /* $NetBSD: clientloop.c,v 1.22 2017/10/07 19:39:19 christos Exp $ */ 2 /* $OpenBSD: clientloop.c,v 1.305 2017/09/19 04:24:22 djm Exp $ */ 3 /* 4 * Author: Tatu Ylonen <ylo@cs.hut.fi> 5 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 6 * All rights reserved 7 * The main loop for the interactive session (client side). 8 * 9 * As far as I am concerned, the code I have written for this software 10 * can be used freely for any purpose. Any derived versions of this 11 * software must be clearly marked as such, and if the derived work is 12 * incompatible with the protocol description in the RFC file, it must be 13 * called by a name other than "ssh" or "Secure Shell". 14 * 15 * 16 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 17 * 18 * Redistribution and use in source and binary forms, with or without 19 * modification, are permitted provided that the following conditions 20 * are met: 21 * 1. Redistributions of source code must retain the above copyright 22 * notice, this list of conditions and the following disclaimer. 23 * 2. Redistributions in binary form must reproduce the above copyright 24 * notice, this list of conditions and the following disclaimer in the 25 * documentation and/or other materials provided with the distribution. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 28 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 29 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 30 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 31 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 32 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 33 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 34 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 35 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 36 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 37 * 38 * 39 * SSH2 support added by Markus Friedl. 40 * Copyright (c) 1999, 2000, 2001 Markus Friedl. All rights reserved. 41 * 42 * Redistribution and use in source and binary forms, with or without 43 * modification, are permitted provided that the following conditions 44 * are met: 45 * 1. Redistributions of source code must retain the above copyright 46 * notice, this list of conditions and the following disclaimer. 47 * 2. Redistributions in binary form must reproduce the above copyright 48 * notice, this list of conditions and the following disclaimer in the 49 * documentation and/or other materials provided with the distribution. 50 * 51 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 52 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 53 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 54 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 55 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 56 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 57 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 58 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 59 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 60 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 61 */ 62 63 #include "includes.h" 64 __RCSID("$NetBSD: clientloop.c,v 1.22 2017/10/07 19:39:19 christos Exp $"); 65 66 #include <sys/types.h> 67 #include <sys/ioctl.h> 68 #include <sys/stat.h> 69 #include <sys/socket.h> 70 #include <sys/time.h> 71 #include <sys/queue.h> 72 73 #include <ctype.h> 74 #include <errno.h> 75 #include <paths.h> 76 #include <signal.h> 77 #include <stdio.h> 78 #include <stdlib.h> 79 #include <string.h> 80 #include <termios.h> 81 #include <pwd.h> 82 #include <unistd.h> 83 #include <limits.h> 84 85 #include "xmalloc.h" 86 #include "ssh.h" 87 #include "ssh2.h" 88 #include "packet.h" 89 #include "buffer.h" 90 #include "compat.h" 91 #include "channels.h" 92 #include "dispatch.h" 93 #include "key.h" 94 #include "cipher.h" 95 #include "kex.h" 96 #include "myproposal.h" 97 #include "log.h" 98 #include "misc.h" 99 #include "readconf.h" 100 #include "clientloop.h" 101 #include "sshconnect.h" 102 #include "authfd.h" 103 #include "atomicio.h" 104 #include "sshpty.h" 105 #include "match.h" 106 #include "msg.h" 107 #include "getpeereid.h" 108 #include "ssherr.h" 109 #include "hostfile.h" 110 111 /* import options */ 112 extern Options options; 113 114 /* Flag indicating that stdin should be redirected from /dev/null. */ 115 extern int stdin_null_flag; 116 117 /* Flag indicating that no shell has been requested */ 118 extern int no_shell_flag; 119 120 /* Flag indicating that ssh should daemonise after authentication is complete */ 121 extern int fork_after_authentication_flag; 122 123 /* Control socket */ 124 extern int muxserver_sock; /* XXX use mux_client_cleanup() instead */ 125 126 /* 127 * Name of the host we are connecting to. This is the name given on the 128 * command line, or the HostName specified for the user-supplied name in a 129 * configuration file. 130 */ 131 extern char *host; 132 133 /* 134 * Flag to indicate that we have received a window change signal which has 135 * not yet been processed. This will cause a message indicating the new 136 * window size to be sent to the server a little later. This is volatile 137 * because this is updated in a signal handler. 138 */ 139 static volatile sig_atomic_t received_window_change_signal = 0; 140 static volatile sig_atomic_t received_signal = 0; 141 142 /* Flag indicating whether the user's terminal is in non-blocking mode. */ 143 static int in_non_blocking_mode = 0; 144 145 /* Time when backgrounded control master using ControlPersist should exit */ 146 static time_t control_persist_exit_time = 0; 147 148 /* Common data for the client loop code. */ 149 volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */ 150 static int last_was_cr; /* Last character was a newline. */ 151 static int exit_status; /* Used to store the command exit status. */ 152 static Buffer stderr_buffer; /* Used for final exit message. */ 153 static int connection_in; /* Connection to server (input). */ 154 static int connection_out; /* Connection to server (output). */ 155 static int need_rekeying; /* Set to non-zero if rekeying is requested. */ 156 static int session_closed; /* In SSH2: login session closed. */ 157 static u_int x11_refuse_time; /* If >0, refuse x11 opens after this time. */ 158 159 static void client_init_dispatch(void); 160 int session_ident = -1; 161 162 /* Track escape per proto2 channel */ 163 struct escape_filter_ctx { 164 int escape_pending; 165 int escape_char; 166 }; 167 168 /* Context for channel confirmation replies */ 169 struct channel_reply_ctx { 170 const char *request_type; 171 int id; 172 enum confirm_action action; 173 }; 174 175 /* Global request success/failure callbacks */ 176 /* XXX move to struct ssh? */ 177 struct global_confirm { 178 TAILQ_ENTRY(global_confirm) entry; 179 global_confirm_cb *cb; 180 void *ctx; 181 int ref_count; 182 }; 183 TAILQ_HEAD(global_confirms, global_confirm); 184 static struct global_confirms global_confirms = 185 TAILQ_HEAD_INITIALIZER(global_confirms); 186 187 void ssh_process_session2_setup(int, int, int, Buffer *); 188 189 /* Restores stdin to blocking mode. */ 190 191 static void 192 leave_non_blocking(void) 193 { 194 if (in_non_blocking_mode) { 195 unset_nonblock(fileno(stdin)); 196 in_non_blocking_mode = 0; 197 } 198 } 199 200 /* 201 * Signal handler for the window change signal (SIGWINCH). This just sets a 202 * flag indicating that the window has changed. 203 */ 204 /*ARGSUSED */ 205 static void 206 window_change_handler(int sig) 207 { 208 received_window_change_signal = 1; 209 signal(SIGWINCH, window_change_handler); 210 } 211 212 /* 213 * Signal handler for signals that cause the program to terminate. These 214 * signals must be trapped to restore terminal modes. 215 */ 216 /*ARGSUSED */ 217 static void 218 signal_handler(int sig) 219 { 220 received_signal = sig; 221 quit_pending = 1; 222 } 223 224 /* 225 * Returns current time in seconds from Jan 1, 1970 with the maximum 226 * available resolution. 227 */ 228 229 static double 230 get_current_time(void) 231 { 232 struct timeval tv; 233 gettimeofday(&tv, NULL); 234 return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0; 235 } 236 237 /* 238 * Sets control_persist_exit_time to the absolute time when the 239 * backgrounded control master should exit due to expiry of the 240 * ControlPersist timeout. Sets it to 0 if we are not a backgrounded 241 * control master process, or if there is no ControlPersist timeout. 242 */ 243 static void 244 set_control_persist_exit_time(struct ssh *ssh) 245 { 246 if (muxserver_sock == -1 || !options.control_persist 247 || options.control_persist_timeout == 0) { 248 /* not using a ControlPersist timeout */ 249 control_persist_exit_time = 0; 250 } else if (channel_still_open(ssh)) { 251 /* some client connections are still open */ 252 if (control_persist_exit_time > 0) 253 debug2("%s: cancel scheduled exit", __func__); 254 control_persist_exit_time = 0; 255 } else if (control_persist_exit_time <= 0) { 256 /* a client connection has recently closed */ 257 control_persist_exit_time = monotime() + 258 (time_t)options.control_persist_timeout; 259 debug2("%s: schedule exit in %d seconds", __func__, 260 options.control_persist_timeout); 261 } 262 /* else we are already counting down to the timeout */ 263 } 264 265 #define SSH_X11_VALID_DISPLAY_CHARS ":/.-_" 266 static int 267 client_x11_display_valid(const char *display) 268 { 269 size_t i, dlen; 270 271 if (display == NULL) 272 return 0; 273 274 dlen = strlen(display); 275 for (i = 0; i < dlen; i++) { 276 if (!isalnum((u_char)display[i]) && 277 strchr(SSH_X11_VALID_DISPLAY_CHARS, display[i]) == NULL) { 278 debug("Invalid character '%c' in DISPLAY", display[i]); 279 return 0; 280 } 281 } 282 return 1; 283 } 284 285 #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1" 286 #define X11_TIMEOUT_SLACK 60 287 int 288 client_x11_get_proto(struct ssh *ssh, const char *display, 289 const char *xauth_path, u_int trusted, u_int timeout, 290 char **_proto, char **_data) 291 { 292 char cmd[1024], line[512], xdisplay[512]; 293 char xauthfile[PATH_MAX], xauthdir[PATH_MAX]; 294 static char proto[512], data[512]; 295 FILE *f; 296 int got_data = 0, generated = 0, do_unlink = 0, r; 297 struct stat st; 298 u_int now, x11_timeout_real; 299 300 *_proto = proto; 301 *_data = data; 302 proto[0] = data[0] = xauthfile[0] = xauthdir[0] = '\0'; 303 304 if (!client_x11_display_valid(display)) { 305 if (display != NULL) 306 logit("DISPLAY \"%s\" invalid; disabling X11 forwarding", 307 display); 308 return -1; 309 } 310 if (xauth_path != NULL && stat(xauth_path, &st) == -1) { 311 debug("No xauth program."); 312 xauth_path = NULL; 313 } 314 315 if (xauth_path != NULL) { 316 /* 317 * Handle FamilyLocal case where $DISPLAY does 318 * not match an authorization entry. For this we 319 * just try "xauth list unix:displaynum.screennum". 320 * XXX: "localhost" match to determine FamilyLocal 321 * is not perfect. 322 */ 323 if (strncmp(display, "localhost:", 10) == 0) { 324 if ((r = snprintf(xdisplay, sizeof(xdisplay), "unix:%s", 325 display + 10)) < 0 || 326 (size_t)r >= sizeof(xdisplay)) { 327 error("%s: display name too long", __func__); 328 return -1; 329 } 330 display = xdisplay; 331 } 332 if (trusted == 0) { 333 /* 334 * Generate an untrusted X11 auth cookie. 335 * 336 * The authentication cookie should briefly outlive 337 * ssh's willingness to forward X11 connections to 338 * avoid nasty fail-open behaviour in the X server. 339 */ 340 mktemp_proto(xauthdir, sizeof(xauthdir)); 341 if (mkdtemp(xauthdir) == NULL) { 342 error("%s: mkdtemp: %s", 343 __func__, strerror(errno)); 344 return -1; 345 } 346 do_unlink = 1; 347 if ((r = snprintf(xauthfile, sizeof(xauthfile), 348 "%s/xauthfile", xauthdir)) < 0 || 349 (size_t)r >= sizeof(xauthfile)) { 350 error("%s: xauthfile path too long", __func__); 351 unlink(xauthfile); 352 rmdir(xauthdir); 353 return -1; 354 } 355 356 if (timeout >= UINT_MAX - X11_TIMEOUT_SLACK) 357 x11_timeout_real = UINT_MAX; 358 else 359 x11_timeout_real = timeout + X11_TIMEOUT_SLACK; 360 if ((r = snprintf(cmd, sizeof(cmd), 361 "%s -f %s generate %s " SSH_X11_PROTO 362 " untrusted timeout %u 2>" _PATH_DEVNULL, 363 xauth_path, xauthfile, display, 364 x11_timeout_real)) < 0 || 365 (size_t)r >= sizeof(cmd)) 366 fatal("%s: cmd too long", __func__); 367 debug2("%s: %s", __func__, cmd); 368 if (x11_refuse_time == 0) { 369 now = monotime() + 1; 370 if (UINT_MAX - timeout < now) 371 x11_refuse_time = UINT_MAX; 372 else 373 x11_refuse_time = now + timeout; 374 channel_set_x11_refuse_time(ssh, 375 x11_refuse_time); 376 } 377 if (system(cmd) == 0) 378 generated = 1; 379 } 380 381 /* 382 * When in untrusted mode, we read the cookie only if it was 383 * successfully generated as an untrusted one in the step 384 * above. 385 */ 386 if (trusted || generated) { 387 snprintf(cmd, sizeof(cmd), 388 "%s %s%s list %s 2>" _PATH_DEVNULL, 389 xauth_path, 390 generated ? "-f " : "" , 391 generated ? xauthfile : "", 392 display); 393 debug2("x11_get_proto: %s", cmd); 394 f = popen(cmd, "r"); 395 if (f && fgets(line, sizeof(line), f) && 396 sscanf(line, "%*s %511s %511s", proto, data) == 2) 397 got_data = 1; 398 if (f) 399 pclose(f); 400 } 401 } 402 403 if (do_unlink) { 404 unlink(xauthfile); 405 rmdir(xauthdir); 406 } 407 408 /* Don't fall back to fake X11 data for untrusted forwarding */ 409 if (!trusted && !got_data) { 410 error("Warning: untrusted X11 forwarding setup failed: " 411 "xauth key data not generated"); 412 return -1; 413 } 414 415 /* 416 * If we didn't get authentication data, just make up some 417 * data. The forwarding code will check the validity of the 418 * response anyway, and substitute this data. The X11 419 * server, however, will ignore this fake data and use 420 * whatever authentication mechanisms it was using otherwise 421 * for the local connection. 422 */ 423 if (!got_data) { 424 u_int8_t rnd[16]; 425 u_int i; 426 427 logit("Warning: No xauth data; " 428 "using fake authentication data for X11 forwarding."); 429 strlcpy(proto, SSH_X11_PROTO, sizeof proto); 430 arc4random_buf(rnd, sizeof(rnd)); 431 for (i = 0; i < sizeof(rnd); i++) { 432 snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", 433 rnd[i]); 434 } 435 } 436 437 return 0; 438 } 439 440 /* 441 * Checks if the client window has changed, and sends a packet about it to 442 * the server if so. The actual change is detected elsewhere (by a software 443 * interrupt on Unix); this just checks the flag and sends a message if 444 * appropriate. 445 */ 446 447 static void 448 client_check_window_change(struct ssh *ssh) 449 { 450 if (!received_window_change_signal) 451 return; 452 /** XXX race */ 453 received_window_change_signal = 0; 454 455 debug2("%s: changed", __func__); 456 457 channel_send_window_changes(ssh); 458 } 459 460 static int 461 client_global_request_reply(int type, u_int32_t seq, struct ssh *ssh) 462 { 463 struct global_confirm *gc; 464 465 if ((gc = TAILQ_FIRST(&global_confirms)) == NULL) 466 return 0; 467 if (gc->cb != NULL) 468 gc->cb(ssh, type, seq, gc->ctx); 469 if (--gc->ref_count <= 0) { 470 TAILQ_REMOVE(&global_confirms, gc, entry); 471 explicit_bzero(gc, sizeof(*gc)); 472 free(gc); 473 } 474 475 packet_set_alive_timeouts(0); 476 return 0; 477 } 478 479 static void 480 server_alive_check(void) 481 { 482 if (packet_inc_alive_timeouts() > options.server_alive_count_max) { 483 logit("Timeout, server %s not responding.", host); 484 cleanup_exit(255); 485 } 486 packet_start(SSH2_MSG_GLOBAL_REQUEST); 487 packet_put_cstring("keepalive@openssh.com"); 488 packet_put_char(1); /* boolean: want reply */ 489 packet_send(); 490 /* Insert an empty placeholder to maintain ordering */ 491 client_register_global_confirm(NULL, NULL); 492 } 493 494 /* 495 * Waits until the client can do something (some data becomes available on 496 * one of the file descriptors). 497 */ 498 static void 499 client_wait_until_can_do_something(struct ssh *ssh, 500 fd_set **readsetp, fd_set **writesetp, 501 int *maxfdp, u_int *nallocp, int rekeying) 502 { 503 struct timeval tv, *tvp; 504 int timeout_secs; 505 time_t minwait_secs = 0, server_alive_time = 0, now = monotime(); 506 int ret; 507 508 /* Add any selections by the channel mechanism. */ 509 channel_prepare_select(active_state, readsetp, writesetp, maxfdp, 510 nallocp, &minwait_secs); 511 512 /* channel_prepare_select could have closed the last channel */ 513 if (session_closed && !channel_still_open(ssh) && 514 !packet_have_data_to_write()) { 515 /* clear mask since we did not call select() */ 516 memset(*readsetp, 0, *nallocp); 517 memset(*writesetp, 0, *nallocp); 518 return; 519 } 520 521 FD_SET(connection_in, *readsetp); 522 523 /* Select server connection if have data to write to the server. */ 524 if (packet_have_data_to_write()) 525 FD_SET(connection_out, *writesetp); 526 527 /* 528 * Wait for something to happen. This will suspend the process until 529 * some selected descriptor can be read, written, or has some other 530 * event pending, or a timeout expires. 531 */ 532 533 timeout_secs = INT_MAX; /* we use INT_MAX to mean no timeout */ 534 if (options.server_alive_interval > 0) { 535 timeout_secs = options.server_alive_interval; 536 server_alive_time = now + options.server_alive_interval; 537 } 538 if (options.rekey_interval > 0 && !rekeying) 539 timeout_secs = MINIMUM(timeout_secs, packet_get_rekey_timeout()); 540 set_control_persist_exit_time(ssh); 541 if (control_persist_exit_time > 0) { 542 timeout_secs = MINIMUM(timeout_secs, 543 control_persist_exit_time - now); 544 if (timeout_secs < 0) 545 timeout_secs = 0; 546 } 547 if (minwait_secs != 0) 548 timeout_secs = MINIMUM(timeout_secs, (int)minwait_secs); 549 if (timeout_secs == INT_MAX) 550 tvp = NULL; 551 else { 552 tv.tv_sec = timeout_secs; 553 tv.tv_usec = 0; 554 tvp = &tv; 555 } 556 557 ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp); 558 if (ret < 0) { 559 char buf[100]; 560 561 /* 562 * We have to clear the select masks, because we return. 563 * We have to return, because the mainloop checks for the flags 564 * set by the signal handlers. 565 */ 566 memset(*readsetp, 0, *nallocp); 567 memset(*writesetp, 0, *nallocp); 568 569 if (errno == EINTR) 570 return; 571 /* Note: we might still have data in the buffers. */ 572 snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno)); 573 buffer_append(&stderr_buffer, buf, strlen(buf)); 574 quit_pending = 1; 575 } else if (ret == 0) { 576 /* 577 * Timeout. Could have been either keepalive or rekeying. 578 * Keepalive we check here, rekeying is checked in clientloop. 579 */ 580 if (server_alive_time != 0 && server_alive_time <= monotime()) 581 server_alive_check(); 582 } 583 584 } 585 586 static void 587 client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr) 588 { 589 /* Flush stdout and stderr buffers. */ 590 if (buffer_len(bout) > 0) 591 atomicio(vwrite, fileno(stdout), buffer_ptr(bout), 592 buffer_len(bout)); 593 if (buffer_len(berr) > 0) 594 atomicio(vwrite, fileno(stderr), buffer_ptr(berr), 595 buffer_len(berr)); 596 597 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 598 599 sshbuf_reset(bin); 600 sshbuf_reset(bout); 601 sshbuf_reset(berr); 602 603 /* Send the suspend signal to the program itself. */ 604 kill(getpid(), SIGTSTP); 605 606 /* Reset window sizes in case they have changed */ 607 received_window_change_signal = 1; 608 609 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 610 } 611 612 static void 613 client_process_net_input(fd_set *readset) 614 { 615 int len; 616 char buf[8192]; 617 618 /* 619 * Read input from the server, and add any such data to the buffer of 620 * the packet subsystem. 621 */ 622 if (FD_ISSET(connection_in, readset)) { 623 /* Read as much as possible. */ 624 len = read(connection_in, buf, sizeof(buf)); 625 if (len == 0) { 626 /* 627 * Received EOF. The remote host has closed the 628 * connection. 629 */ 630 snprintf(buf, sizeof buf, 631 "Connection to %.300s closed by remote host.\r\n", 632 host); 633 buffer_append(&stderr_buffer, buf, strlen(buf)); 634 quit_pending = 1; 635 return; 636 } 637 /* 638 * There is a kernel bug on Solaris that causes select to 639 * sometimes wake up even though there is no data available. 640 */ 641 if (len < 0 && (errno == EAGAIN || errno == EINTR)) 642 len = 0; 643 644 if (len < 0) { 645 /* 646 * An error has encountered. Perhaps there is a 647 * network problem. 648 */ 649 snprintf(buf, sizeof buf, 650 "Read from remote host %.300s: %.100s\r\n", 651 host, strerror(errno)); 652 buffer_append(&stderr_buffer, buf, strlen(buf)); 653 quit_pending = 1; 654 return; 655 } 656 packet_process_incoming(buf, len); 657 } 658 } 659 660 static void 661 client_status_confirm(struct ssh *ssh, int type, Channel *c, void *ctx) 662 { 663 struct channel_reply_ctx *cr = (struct channel_reply_ctx *)ctx; 664 char errmsg[256]; 665 int tochan; 666 667 /* 668 * If a TTY was explicitly requested, then a failure to allocate 669 * one is fatal. 670 */ 671 if (cr->action == CONFIRM_TTY && 672 (options.request_tty == REQUEST_TTY_FORCE || 673 options.request_tty == REQUEST_TTY_YES)) 674 cr->action = CONFIRM_CLOSE; 675 676 /* XXX supress on mux _client_ quietmode */ 677 tochan = options.log_level >= SYSLOG_LEVEL_ERROR && 678 c->ctl_chan != -1 && c->extended_usage == CHAN_EXTENDED_WRITE; 679 680 if (type == SSH2_MSG_CHANNEL_SUCCESS) { 681 debug2("%s request accepted on channel %d", 682 cr->request_type, c->self); 683 } else if (type == SSH2_MSG_CHANNEL_FAILURE) { 684 if (tochan) { 685 snprintf(errmsg, sizeof(errmsg), 686 "%s request failed\r\n", cr->request_type); 687 } else { 688 snprintf(errmsg, sizeof(errmsg), 689 "%s request failed on channel %d", 690 cr->request_type, c->self); 691 } 692 /* If error occurred on primary session channel, then exit */ 693 if (cr->action == CONFIRM_CLOSE && c->self == session_ident) 694 fatal("%s", errmsg); 695 /* 696 * If error occurred on mux client, append to 697 * their stderr. 698 */ 699 if (tochan) { 700 buffer_append(c->extended, errmsg, strlen(errmsg)); 701 } else 702 error("%s", errmsg); 703 if (cr->action == CONFIRM_TTY) { 704 /* 705 * If a TTY allocation error occurred, then arrange 706 * for the correct TTY to leave raw mode. 707 */ 708 if (c->self == session_ident) 709 leave_raw_mode(0); 710 else 711 mux_tty_alloc_failed(ssh, c); 712 } else if (cr->action == CONFIRM_CLOSE) { 713 chan_read_failed(ssh, c); 714 chan_write_failed(ssh, c); 715 } 716 } 717 free(cr); 718 } 719 720 static void 721 client_abandon_status_confirm(struct ssh *ssh, Channel *c, void *ctx) 722 { 723 free(ctx); 724 } 725 726 void 727 client_expect_confirm(struct ssh *ssh, int id, const char *request, 728 enum confirm_action action) 729 { 730 struct channel_reply_ctx *cr = xcalloc(1, sizeof(*cr)); 731 732 cr->request_type = request; 733 cr->action = action; 734 735 channel_register_status_confirm(ssh, id, client_status_confirm, 736 client_abandon_status_confirm, cr); 737 } 738 739 void 740 client_register_global_confirm(global_confirm_cb *cb, void *ctx) 741 { 742 struct global_confirm *gc, *last_gc; 743 744 /* Coalesce identical callbacks */ 745 last_gc = TAILQ_LAST(&global_confirms, global_confirms); 746 if (last_gc && last_gc->cb == cb && last_gc->ctx == ctx) { 747 if (++last_gc->ref_count >= INT_MAX) 748 fatal("%s: last_gc->ref_count = %d", 749 __func__, last_gc->ref_count); 750 return; 751 } 752 753 gc = xcalloc(1, sizeof(*gc)); 754 gc->cb = cb; 755 gc->ctx = ctx; 756 gc->ref_count = 1; 757 TAILQ_INSERT_TAIL(&global_confirms, gc, entry); 758 } 759 760 static void 761 process_cmdline(struct ssh *ssh) 762 { 763 void (*handler)(int); 764 char *s, *cmd; 765 int ok, delete = 0, local = 0, remote = 0, dynamic = 0; 766 struct Forward fwd; 767 768 memset(&fwd, 0, sizeof(fwd)); 769 770 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 771 handler = signal(SIGINT, SIG_IGN); 772 cmd = s = read_passphrase("\r\nssh> ", RP_ECHO); 773 if (s == NULL) 774 goto out; 775 while (isspace((u_char)*s)) 776 s++; 777 if (*s == '-') 778 s++; /* Skip cmdline '-', if any */ 779 if (*s == '\0') 780 goto out; 781 782 if (*s == 'h' || *s == 'H' || *s == '?') { 783 logit("Commands:"); 784 logit(" -L[bind_address:]port:host:hostport " 785 "Request local forward"); 786 logit(" -R[bind_address:]port:host:hostport " 787 "Request remote forward"); 788 logit(" -D[bind_address:]port " 789 "Request dynamic forward"); 790 logit(" -KL[bind_address:]port " 791 "Cancel local forward"); 792 logit(" -KR[bind_address:]port " 793 "Cancel remote forward"); 794 logit(" -KD[bind_address:]port " 795 "Cancel dynamic forward"); 796 if (!options.permit_local_command) 797 goto out; 798 logit(" !args " 799 "Execute local command"); 800 goto out; 801 } 802 803 if (*s == '!' && options.permit_local_command) { 804 s++; 805 ssh_local_cmd(s); 806 goto out; 807 } 808 809 if (*s == 'K') { 810 delete = 1; 811 s++; 812 } 813 if (*s == 'L') 814 local = 1; 815 else if (*s == 'R') 816 remote = 1; 817 else if (*s == 'D') 818 dynamic = 1; 819 else { 820 logit("Invalid command."); 821 goto out; 822 } 823 824 while (isspace((u_char)*++s)) 825 ; 826 827 /* XXX update list of forwards in options */ 828 if (delete) { 829 /* We pass 1 for dynamicfwd to restrict to 1 or 2 fields. */ 830 if (!parse_forward(&fwd, s, 1, 0)) { 831 logit("Bad forwarding close specification."); 832 goto out; 833 } 834 if (remote) 835 ok = channel_request_rforward_cancel(ssh, &fwd) == 0; 836 else if (dynamic) 837 ok = channel_cancel_lport_listener(ssh, &fwd, 838 0, &options.fwd_opts) > 0; 839 else 840 ok = channel_cancel_lport_listener(ssh, &fwd, 841 CHANNEL_CANCEL_PORT_STATIC, 842 &options.fwd_opts) > 0; 843 if (!ok) { 844 logit("Unknown port forwarding."); 845 goto out; 846 } 847 logit("Canceled forwarding."); 848 } else { 849 if (!parse_forward(&fwd, s, dynamic, remote)) { 850 logit("Bad forwarding specification."); 851 goto out; 852 } 853 if (local || dynamic) { 854 if (!channel_setup_local_fwd_listener(ssh, &fwd, 855 &options.fwd_opts)) { 856 logit("Port forwarding failed."); 857 goto out; 858 } 859 } else { 860 if (channel_request_remote_forwarding(ssh, &fwd) < 0) { 861 logit("Port forwarding failed."); 862 goto out; 863 } 864 } 865 logit("Forwarding port."); 866 } 867 868 out: 869 signal(SIGINT, handler); 870 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 871 free(cmd); 872 free(fwd.listen_host); 873 free(fwd.listen_path); 874 free(fwd.connect_host); 875 free(fwd.connect_path); 876 } 877 878 /* reasons to suppress output of an escape command in help output */ 879 #define SUPPRESS_NEVER 0 /* never suppress, always show */ 880 #define SUPPRESS_MUXCLIENT 1 /* don't show in mux client sessions */ 881 #define SUPPRESS_MUXMASTER 2 /* don't show in mux master sessions */ 882 #define SUPPRESS_SYSLOG 4 /* don't show when logging to syslog */ 883 struct escape_help_text { 884 const char *cmd; 885 const char *text; 886 unsigned int flags; 887 }; 888 static struct escape_help_text esc_txt[] = { 889 {".", "terminate session", SUPPRESS_MUXMASTER}, 890 {".", "terminate connection (and any multiplexed sessions)", 891 SUPPRESS_MUXCLIENT}, 892 {"B", "send a BREAK to the remote system", SUPPRESS_NEVER}, 893 {"C", "open a command line", SUPPRESS_MUXCLIENT}, 894 {"R", "request rekey", SUPPRESS_NEVER}, 895 {"V/v", "decrease/increase verbosity (LogLevel)", SUPPRESS_MUXCLIENT}, 896 {"^Z", "suspend ssh", SUPPRESS_MUXCLIENT}, 897 {"#", "list forwarded connections", SUPPRESS_NEVER}, 898 {"&", "background ssh (when waiting for connections to terminate)", 899 SUPPRESS_MUXCLIENT}, 900 {"?", "this message", SUPPRESS_NEVER}, 901 }; 902 903 static void 904 print_escape_help(Buffer *b, int escape_char, int mux_client, int using_stderr) 905 { 906 unsigned int i, suppress_flags; 907 char string[1024]; 908 909 snprintf(string, sizeof string, "%c?\r\n" 910 "Supported escape sequences:\r\n", escape_char); 911 buffer_append(b, string, strlen(string)); 912 913 suppress_flags = 914 (mux_client ? SUPPRESS_MUXCLIENT : 0) | 915 (mux_client ? 0 : SUPPRESS_MUXMASTER) | 916 (using_stderr ? 0 : SUPPRESS_SYSLOG); 917 918 for (i = 0; i < sizeof(esc_txt)/sizeof(esc_txt[0]); i++) { 919 if (esc_txt[i].flags & suppress_flags) 920 continue; 921 snprintf(string, sizeof string, " %c%-3s - %s\r\n", 922 escape_char, esc_txt[i].cmd, esc_txt[i].text); 923 buffer_append(b, string, strlen(string)); 924 } 925 926 snprintf(string, sizeof string, 927 " %c%c - send the escape character by typing it twice\r\n" 928 "(Note that escapes are only recognized immediately after " 929 "newline.)\r\n", escape_char, escape_char); 930 buffer_append(b, string, strlen(string)); 931 } 932 933 /* 934 * Process the characters one by one. 935 */ 936 static int 937 process_escapes(struct ssh *ssh, Channel *c, 938 Buffer *bin, Buffer *bout, Buffer *berr, 939 const char *buf, int len) 940 { 941 char string[1024]; 942 pid_t pid; 943 int bytes = 0; 944 u_int i; 945 u_char ch; 946 char *s; 947 struct escape_filter_ctx *efc = c->filter_ctx == NULL ? 948 NULL : (struct escape_filter_ctx *)c->filter_ctx; 949 950 if (c->filter_ctx == NULL) 951 return 0; 952 953 if (len <= 0) 954 return (0); 955 956 for (i = 0; i < (u_int)len; i++) { 957 /* Get one character at a time. */ 958 ch = buf[i]; 959 960 if (efc->escape_pending) { 961 /* We have previously seen an escape character. */ 962 /* Clear the flag now. */ 963 efc->escape_pending = 0; 964 965 /* Process the escaped character. */ 966 switch (ch) { 967 case '.': 968 /* Terminate the connection. */ 969 snprintf(string, sizeof string, "%c.\r\n", 970 efc->escape_char); 971 buffer_append(berr, string, strlen(string)); 972 973 if (c && c->ctl_chan != -1) { 974 chan_read_failed(ssh, c); 975 chan_write_failed(ssh, c); 976 if (c->detach_user) { 977 c->detach_user(ssh, 978 c->self, NULL); 979 } 980 c->type = SSH_CHANNEL_ABANDONED; 981 buffer_clear(c->input); 982 chan_ibuf_empty(ssh, c); 983 return 0; 984 } else 985 quit_pending = 1; 986 return -1; 987 988 case 'Z' - 64: 989 /* XXX support this for mux clients */ 990 if (c && c->ctl_chan != -1) { 991 char b[16]; 992 noescape: 993 if (ch == 'Z' - 64) 994 snprintf(b, sizeof b, "^Z"); 995 else 996 snprintf(b, sizeof b, "%c", ch); 997 snprintf(string, sizeof string, 998 "%c%s escape not available to " 999 "multiplexed sessions\r\n", 1000 efc->escape_char, b); 1001 buffer_append(berr, string, 1002 strlen(string)); 1003 continue; 1004 } 1005 /* Suspend the program. Inform the user */ 1006 snprintf(string, sizeof string, 1007 "%c^Z [suspend ssh]\r\n", efc->escape_char); 1008 buffer_append(berr, string, strlen(string)); 1009 1010 /* Restore terminal modes and suspend. */ 1011 client_suspend_self(bin, bout, berr); 1012 1013 /* We have been continued. */ 1014 continue; 1015 1016 case 'B': 1017 snprintf(string, sizeof string, 1018 "%cB\r\n", efc->escape_char); 1019 buffer_append(berr, string, strlen(string)); 1020 channel_request_start(ssh, c->self, "break", 0); 1021 packet_put_int(1000); 1022 packet_send(); 1023 continue; 1024 1025 case 'R': 1026 if (datafellows & SSH_BUG_NOREKEY) 1027 logit("Server does not " 1028 "support re-keying"); 1029 else 1030 need_rekeying = 1; 1031 continue; 1032 1033 case 'V': 1034 /* FALLTHROUGH */ 1035 case 'v': 1036 if (c && c->ctl_chan != -1) 1037 goto noescape; 1038 if (!log_is_on_stderr()) { 1039 snprintf(string, sizeof string, 1040 "%c%c [Logging to syslog]\r\n", 1041 efc->escape_char, ch); 1042 buffer_append(berr, string, 1043 strlen(string)); 1044 continue; 1045 } 1046 if (ch == 'V' && options.log_level > 1047 SYSLOG_LEVEL_QUIET) 1048 log_change_level(--options.log_level); 1049 if (ch == 'v' && options.log_level < 1050 SYSLOG_LEVEL_DEBUG3) 1051 log_change_level(++options.log_level); 1052 snprintf(string, sizeof string, 1053 "%c%c [LogLevel %s]\r\n", 1054 efc->escape_char, ch, 1055 log_level_name(options.log_level)); 1056 buffer_append(berr, string, strlen(string)); 1057 continue; 1058 1059 case '&': 1060 if (c && c->ctl_chan != -1) 1061 goto noescape; 1062 /* 1063 * Detach the program (continue to serve 1064 * connections, but put in background and no 1065 * more new connections). 1066 */ 1067 /* Restore tty modes. */ 1068 leave_raw_mode( 1069 options.request_tty == REQUEST_TTY_FORCE); 1070 1071 /* Stop listening for new connections. */ 1072 channel_stop_listening(ssh); 1073 1074 snprintf(string, sizeof string, 1075 "%c& [backgrounded]\n", efc->escape_char); 1076 buffer_append(berr, string, strlen(string)); 1077 1078 /* Fork into background. */ 1079 pid = fork(); 1080 if (pid < 0) { 1081 error("fork: %.100s", strerror(errno)); 1082 continue; 1083 } 1084 if (pid != 0) { /* This is the parent. */ 1085 /* The parent just exits. */ 1086 exit(0); 1087 } 1088 /* The child continues serving connections. */ 1089 buffer_append(bin, "\004", 1); 1090 /* fake EOF on stdin */ 1091 return -1; 1092 case '?': 1093 print_escape_help(berr, efc->escape_char, 1094 (c && c->ctl_chan != -1), 1095 log_is_on_stderr()); 1096 continue; 1097 1098 case '#': 1099 snprintf(string, sizeof string, "%c#\r\n", 1100 efc->escape_char); 1101 buffer_append(berr, string, strlen(string)); 1102 s = channel_open_message(ssh); 1103 buffer_append(berr, s, strlen(s)); 1104 free(s); 1105 continue; 1106 1107 case 'C': 1108 if (c && c->ctl_chan != -1) 1109 goto noescape; 1110 process_cmdline(ssh); 1111 continue; 1112 1113 default: 1114 if (ch != efc->escape_char) { 1115 buffer_put_char(bin, efc->escape_char); 1116 bytes++; 1117 } 1118 /* Escaped characters fall through here */ 1119 break; 1120 } 1121 } else { 1122 /* 1123 * The previous character was not an escape char. 1124 * Check if this is an escape. 1125 */ 1126 if (last_was_cr && ch == efc->escape_char) { 1127 /* 1128 * It is. Set the flag and continue to 1129 * next character. 1130 */ 1131 efc->escape_pending = 1; 1132 continue; 1133 } 1134 } 1135 1136 /* 1137 * Normal character. Record whether it was a newline, 1138 * and append it to the buffer. 1139 */ 1140 last_was_cr = (ch == '\r' || ch == '\n'); 1141 buffer_put_char(bin, ch); 1142 bytes++; 1143 } 1144 return bytes; 1145 } 1146 1147 /* 1148 * Get packets from the connection input buffer, and process them as long as 1149 * there are packets available. 1150 * 1151 * Any unknown packets received during the actual 1152 * session cause the session to terminate. This is 1153 * intended to make debugging easier since no 1154 * confirmations are sent. Any compatible protocol 1155 * extensions must be negotiated during the 1156 * preparatory phase. 1157 */ 1158 1159 static void 1160 client_process_buffered_input_packets(void) 1161 { 1162 ssh_dispatch_run_fatal(active_state, DISPATCH_NONBLOCK, &quit_pending); 1163 } 1164 1165 /* scan buf[] for '~' before sending data to the peer */ 1166 1167 /* Helper: allocate a new escape_filter_ctx and fill in its escape char */ 1168 void * 1169 client_new_escape_filter_ctx(int escape_char) 1170 { 1171 struct escape_filter_ctx *ret; 1172 1173 ret = xcalloc(1, sizeof(*ret)); 1174 ret->escape_pending = 0; 1175 ret->escape_char = escape_char; 1176 return (void *)ret; 1177 } 1178 1179 /* Free the escape filter context on channel free */ 1180 void 1181 client_filter_cleanup(struct ssh *ssh, int cid, void *ctx) 1182 { 1183 free(ctx); 1184 } 1185 1186 int 1187 client_simple_escape_filter(struct ssh *ssh, Channel *c, const char *buf, 1188 int len) 1189 { 1190 if (c->extended_usage != CHAN_EXTENDED_WRITE) 1191 return 0; 1192 1193 return process_escapes(ssh, c, c->input, c->output, c->extended, 1194 buf, len); 1195 } 1196 1197 static void 1198 client_channel_closed(struct ssh *ssh, int id, void *arg) 1199 { 1200 channel_cancel_cleanup(ssh, id); 1201 session_closed = 1; 1202 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1203 } 1204 1205 /* 1206 * Implements the interactive session with the server. This is called after 1207 * the user has been authenticated, and a command has been started on the 1208 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character 1209 * used as an escape character for terminating or suspending the session. 1210 */ 1211 int 1212 client_loop(struct ssh *ssh, int have_pty, int escape_char_arg, 1213 int ssh2_chan_id) 1214 { 1215 fd_set *readset = NULL, *writeset = NULL; 1216 double start_time, total_time; 1217 int r, max_fd = 0, max_fd2 = 0, len; 1218 u_int64_t ibytes, obytes; 1219 u_int nalloc = 0; 1220 char buf[100]; 1221 1222 debug("Entering interactive session."); 1223 1224 #ifdef __OpenBSD__ 1225 if (options.control_master && 1226 !option_clear_or_none(options.control_path)) { 1227 debug("pledge: id"); 1228 if (pledge("stdio rpath wpath cpath unix inet dns recvfd proc exec id tty", 1229 NULL) == -1) 1230 fatal("%s pledge(): %s", __func__, strerror(errno)); 1231 1232 } else if (options.forward_x11 || options.permit_local_command) { 1233 debug("pledge: exec"); 1234 if (pledge("stdio rpath wpath cpath unix inet dns proc exec tty", 1235 NULL) == -1) 1236 fatal("%s pledge(): %s", __func__, strerror(errno)); 1237 1238 } else if (options.update_hostkeys) { 1239 debug("pledge: filesystem full"); 1240 if (pledge("stdio rpath wpath cpath unix inet dns proc tty", 1241 NULL) == -1) 1242 fatal("%s pledge(): %s", __func__, strerror(errno)); 1243 1244 } else if (!option_clear_or_none(options.proxy_command) || 1245 fork_after_authentication_flag) { 1246 debug("pledge: proc"); 1247 if (pledge("stdio cpath unix inet dns proc tty", NULL) == -1) 1248 fatal("%s pledge(): %s", __func__, strerror(errno)); 1249 1250 } else { 1251 debug("pledge: network"); 1252 if (pledge("stdio unix inet dns proc tty", NULL) == -1) 1253 fatal("%s pledge(): %s", __func__, strerror(errno)); 1254 } 1255 #endif 1256 1257 start_time = get_current_time(); 1258 1259 /* Initialize variables. */ 1260 last_was_cr = 1; 1261 exit_status = -1; 1262 connection_in = packet_get_connection_in(); 1263 connection_out = packet_get_connection_out(); 1264 max_fd = MAXIMUM(connection_in, connection_out); 1265 1266 quit_pending = 0; 1267 1268 /* Initialize buffers. */ 1269 buffer_init(&stderr_buffer); 1270 1271 client_init_dispatch(); 1272 1273 /* 1274 * Set signal handlers, (e.g. to restore non-blocking mode) 1275 * but don't overwrite SIG_IGN, matches behaviour from rsh(1) 1276 */ 1277 if (signal(SIGHUP, SIG_IGN) != SIG_IGN) 1278 signal(SIGHUP, signal_handler); 1279 if (signal(SIGINT, SIG_IGN) != SIG_IGN) 1280 signal(SIGINT, signal_handler); 1281 if (signal(SIGQUIT, SIG_IGN) != SIG_IGN) 1282 signal(SIGQUIT, signal_handler); 1283 if (signal(SIGTERM, SIG_IGN) != SIG_IGN) 1284 signal(SIGTERM, signal_handler); 1285 signal(SIGWINCH, window_change_handler); 1286 1287 if (have_pty) 1288 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1289 1290 session_ident = ssh2_chan_id; 1291 if (session_ident != -1) { 1292 if (escape_char_arg != SSH_ESCAPECHAR_NONE) { 1293 channel_register_filter(ssh, session_ident, 1294 client_simple_escape_filter, NULL, 1295 client_filter_cleanup, 1296 client_new_escape_filter_ctx( 1297 escape_char_arg)); 1298 } 1299 channel_register_cleanup(ssh, session_ident, 1300 client_channel_closed, 0); 1301 } 1302 1303 /* Main loop of the client for the interactive session mode. */ 1304 while (!quit_pending) { 1305 1306 /* Process buffered packets sent by the server. */ 1307 client_process_buffered_input_packets(); 1308 1309 if (session_closed && !channel_still_open(ssh)) 1310 break; 1311 1312 if (ssh_packet_is_rekeying(ssh)) { 1313 debug("rekeying in progress"); 1314 } else if (need_rekeying) { 1315 /* manual rekey request */ 1316 debug("need rekeying"); 1317 if ((r = kex_start_rekex(ssh)) != 0) 1318 fatal("%s: kex_start_rekex: %s", __func__, 1319 ssh_err(r)); 1320 need_rekeying = 0; 1321 } else { 1322 /* 1323 * Make packets from buffered channel data, and 1324 * enqueue them for sending to the server. 1325 */ 1326 if (packet_not_very_much_data_to_write()) 1327 channel_output_poll(ssh); 1328 1329 /* 1330 * Check if the window size has changed, and buffer a 1331 * message about it to the server if so. 1332 */ 1333 client_check_window_change(ssh); 1334 1335 if (quit_pending) 1336 break; 1337 } 1338 /* 1339 * Wait until we have something to do (something becomes 1340 * available on one of the descriptors). 1341 */ 1342 max_fd2 = max_fd; 1343 client_wait_until_can_do_something(ssh, &readset, &writeset, 1344 &max_fd2, &nalloc, ssh_packet_is_rekeying(ssh)); 1345 1346 if (quit_pending) 1347 break; 1348 1349 /* Do channel operations unless rekeying in progress. */ 1350 if (!ssh_packet_is_rekeying(ssh)) 1351 channel_after_select(ssh, readset, writeset); 1352 1353 /* Buffer input from the connection. */ 1354 client_process_net_input(readset); 1355 1356 if (quit_pending) 1357 break; 1358 1359 /* 1360 * Send as much buffered packet data as possible to the 1361 * sender. 1362 */ 1363 if (FD_ISSET(connection_out, writeset)) 1364 packet_write_poll(); 1365 1366 /* 1367 * If we are a backgrounded control master, and the 1368 * timeout has expired without any active client 1369 * connections, then quit. 1370 */ 1371 if (control_persist_exit_time > 0) { 1372 if (monotime() >= control_persist_exit_time) { 1373 debug("ControlPersist timeout expired"); 1374 break; 1375 } 1376 } 1377 } 1378 free(readset); 1379 free(writeset); 1380 1381 /* Terminate the session. */ 1382 1383 /* Stop watching for window change. */ 1384 signal(SIGWINCH, SIG_DFL); 1385 1386 packet_start(SSH2_MSG_DISCONNECT); 1387 packet_put_int(SSH2_DISCONNECT_BY_APPLICATION); 1388 packet_put_cstring("disconnected by user"); 1389 packet_put_cstring(""); /* language tag */ 1390 packet_send(); 1391 packet_write_wait(); 1392 1393 channel_free_all(ssh); 1394 1395 if (have_pty) 1396 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1397 1398 /* restore blocking io */ 1399 if (!isatty(fileno(stdin))) 1400 unset_nonblock(fileno(stdin)); 1401 if (!isatty(fileno(stdout))) 1402 unset_nonblock(fileno(stdout)); 1403 if (!isatty(fileno(stderr))) 1404 unset_nonblock(fileno(stderr)); 1405 1406 /* 1407 * If there was no shell or command requested, there will be no remote 1408 * exit status to be returned. In that case, clear error code if the 1409 * connection was deliberately terminated at this end. 1410 */ 1411 if (no_shell_flag && received_signal == SIGTERM) { 1412 received_signal = 0; 1413 exit_status = 0; 1414 } 1415 1416 if (received_signal) { 1417 verbose("Killed by signal %d.", (int) received_signal); 1418 cleanup_exit(0); 1419 } 1420 1421 /* 1422 * In interactive mode (with pseudo tty) display a message indicating 1423 * that the connection has been closed. 1424 */ 1425 if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) { 1426 snprintf(buf, sizeof buf, 1427 "Connection to %.64s closed.\r\n", host); 1428 buffer_append(&stderr_buffer, buf, strlen(buf)); 1429 } 1430 1431 /* Output any buffered data for stderr. */ 1432 if (buffer_len(&stderr_buffer) > 0) { 1433 len = atomicio(vwrite, fileno(stderr), 1434 buffer_ptr(&stderr_buffer), buffer_len(&stderr_buffer)); 1435 if (len < 0 || (u_int)len != buffer_len(&stderr_buffer)) 1436 error("Write failed flushing stderr buffer."); 1437 else 1438 buffer_consume(&stderr_buffer, len); 1439 } 1440 1441 /* Clear and free any buffers. */ 1442 explicit_bzero(buf, sizeof(buf)); 1443 buffer_free(&stderr_buffer); 1444 1445 /* Report bytes transferred, and transfer rates. */ 1446 total_time = get_current_time() - start_time; 1447 packet_get_bytes(&ibytes, &obytes); 1448 verbose("Transferred: sent %llu, received %llu bytes, in %.1f seconds", 1449 (unsigned long long)obytes, (unsigned long long)ibytes, total_time); 1450 if (total_time > 0) 1451 verbose("Bytes per second: sent %.1f, received %.1f", 1452 obytes / total_time, ibytes / total_time); 1453 /* Return the exit status of the program. */ 1454 debug("Exit status %d", exit_status); 1455 return exit_status; 1456 } 1457 1458 /*********/ 1459 1460 static Channel * 1461 client_request_forwarded_tcpip(struct ssh *ssh, const char *request_type, 1462 int rchan, u_int rwindow, u_int rmaxpack) 1463 { 1464 Channel *c = NULL; 1465 struct sshbuf *b = NULL; 1466 char *listen_address, *originator_address; 1467 u_short listen_port, originator_port; 1468 int r; 1469 1470 /* Get rest of the packet */ 1471 listen_address = packet_get_string(NULL); 1472 listen_port = packet_get_int(); 1473 originator_address = packet_get_string(NULL); 1474 originator_port = packet_get_int(); 1475 packet_check_eom(); 1476 1477 debug("%s: listen %s port %d, originator %s port %d", __func__, 1478 listen_address, listen_port, originator_address, originator_port); 1479 1480 c = channel_connect_by_listen_address(ssh, listen_address, listen_port, 1481 "forwarded-tcpip", originator_address); 1482 1483 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) { 1484 if ((b = sshbuf_new()) == NULL) { 1485 error("%s: alloc reply", __func__); 1486 goto out; 1487 } 1488 /* reconstruct and send to muxclient */ 1489 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 1490 (r = sshbuf_put_u8(b, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1491 (r = sshbuf_put_cstring(b, request_type)) != 0 || 1492 (r = sshbuf_put_u32(b, rchan)) != 0 || 1493 (r = sshbuf_put_u32(b, rwindow)) != 0 || 1494 (r = sshbuf_put_u32(b, rmaxpack)) != 0 || 1495 (r = sshbuf_put_cstring(b, listen_address)) != 0 || 1496 (r = sshbuf_put_u32(b, listen_port)) != 0 || 1497 (r = sshbuf_put_cstring(b, originator_address)) != 0 || 1498 (r = sshbuf_put_u32(b, originator_port)) != 0 || 1499 (r = sshbuf_put_stringb(c->output, b)) != 0) { 1500 error("%s: compose for muxclient %s", __func__, 1501 ssh_err(r)); 1502 goto out; 1503 } 1504 } 1505 1506 out: 1507 sshbuf_free(b); 1508 free(originator_address); 1509 free(listen_address); 1510 return c; 1511 } 1512 1513 static Channel * 1514 client_request_forwarded_streamlocal(struct ssh *ssh, 1515 const char *request_type, int rchan) 1516 { 1517 Channel *c = NULL; 1518 char *listen_path; 1519 1520 /* Get the remote path. */ 1521 listen_path = packet_get_string(NULL); 1522 /* XXX: Skip reserved field for now. */ 1523 if (packet_get_string_ptr(NULL) == NULL) 1524 fatal("%s: packet_get_string_ptr failed", __func__); 1525 packet_check_eom(); 1526 1527 debug("%s: %s", __func__, listen_path); 1528 1529 c = channel_connect_by_listen_path(ssh, listen_path, 1530 "forwarded-streamlocal@openssh.com", "forwarded-streamlocal"); 1531 free(listen_path); 1532 return c; 1533 } 1534 1535 static Channel * 1536 client_request_x11(struct ssh *ssh, const char *request_type, int rchan) 1537 { 1538 Channel *c = NULL; 1539 char *originator; 1540 u_short originator_port; 1541 int sock; 1542 1543 if (!options.forward_x11) { 1544 error("Warning: ssh server tried X11 forwarding."); 1545 error("Warning: this is probably a break-in attempt by a " 1546 "malicious server."); 1547 return NULL; 1548 } 1549 if (x11_refuse_time != 0 && (u_int)monotime() >= x11_refuse_time) { 1550 verbose("Rejected X11 connection after ForwardX11Timeout " 1551 "expired"); 1552 return NULL; 1553 } 1554 originator = packet_get_string(NULL); 1555 if (datafellows & SSH_BUG_X11FWD) { 1556 debug2("buggy server: x11 request w/o originator_port"); 1557 originator_port = 0; 1558 } else { 1559 originator_port = packet_get_int(); 1560 } 1561 packet_check_eom(); 1562 /* XXX check permission */ 1563 debug("client_request_x11: request from %s %d", originator, 1564 originator_port); 1565 free(originator); 1566 sock = x11_connect_display(ssh); 1567 if (sock < 0) 1568 return NULL; 1569 /* again is this really necessary for X11? */ 1570 if (options.hpn_disabled) 1571 c = channel_new(ssh, "x11", 1572 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1573 CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); 1574 else 1575 c = channel_new(ssh, "x11", 1576 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1577 options.hpn_buffer_size, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); 1578 c->force_drain = 1; 1579 return c; 1580 } 1581 1582 static Channel * 1583 client_request_agent(struct ssh *ssh, const char *request_type, int rchan) 1584 { 1585 Channel *c = NULL; 1586 int r, sock; 1587 1588 if (!options.forward_agent) { 1589 error("Warning: ssh server tried agent forwarding."); 1590 error("Warning: this is probably a break-in attempt by a " 1591 "malicious server."); 1592 return NULL; 1593 } 1594 if ((r = ssh_get_authentication_socket(&sock)) != 0) { 1595 if (r != SSH_ERR_AGENT_NOT_PRESENT) 1596 debug("%s: ssh_get_authentication_socket: %s", 1597 __func__, ssh_err(r)); 1598 return NULL; 1599 } 1600 if (options.hpn_disabled) 1601 c = channel_new(ssh, "authentication agent connection", 1602 SSH_CHANNEL_OPEN, sock, sock, -1, 1603 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, 1604 "authentication agent connection", 1); 1605 else 1606 c = channel_new(ssh, "authentication agent connection", 1607 SSH_CHANNEL_OPEN, sock, sock, -1, 1608 options.hpn_buffer_size, options.hpn_buffer_size, 0, 1609 "authentication agent connection", 1); 1610 c->force_drain = 1; 1611 return c; 1612 } 1613 1614 int 1615 client_request_tun_fwd(struct ssh *ssh, int tun_mode, 1616 int local_tun, int remote_tun) 1617 { 1618 Channel *c; 1619 int fd; 1620 1621 if (tun_mode == SSH_TUNMODE_NO) 1622 return 0; 1623 1624 debug("Requesting tun unit %d in mode %d", local_tun, tun_mode); 1625 1626 /* Open local tunnel device */ 1627 if ((fd = tun_open(local_tun, tun_mode)) == -1) { 1628 error("Tunnel device open failed."); 1629 return -1; 1630 } 1631 1632 if(options.hpn_disabled) 1633 c = channel_new(ssh, "tun", SSH_CHANNEL_OPENING, fd, fd, -1, 1634 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1); 1635 else 1636 c = channel_new(ssh, "tun", SSH_CHANNEL_OPENING, fd, fd, -1, 1637 options.hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1); 1638 c->datagram = 1; 1639 1640 packet_start(SSH2_MSG_CHANNEL_OPEN); 1641 packet_put_cstring("tun@openssh.com"); 1642 packet_put_int(c->self); 1643 packet_put_int(c->local_window_max); 1644 packet_put_int(c->local_maxpacket); 1645 packet_put_int(tun_mode); 1646 packet_put_int(remote_tun); 1647 packet_send(); 1648 1649 return 0; 1650 } 1651 1652 /* XXXX move to generic input handler */ 1653 static int 1654 client_input_channel_open(int type, u_int32_t seq, struct ssh *ssh) 1655 { 1656 Channel *c = NULL; 1657 char *ctype; 1658 int rchan; 1659 u_int rmaxpack, rwindow, len; 1660 1661 ctype = packet_get_string(&len); 1662 rchan = packet_get_int(); 1663 rwindow = packet_get_int(); 1664 rmaxpack = packet_get_int(); 1665 1666 debug("client_input_channel_open: ctype %s rchan %d win %d max %d", 1667 ctype, rchan, rwindow, rmaxpack); 1668 1669 if (strcmp(ctype, "forwarded-tcpip") == 0) { 1670 c = client_request_forwarded_tcpip(ssh, ctype, rchan, rwindow, 1671 rmaxpack); 1672 } else if (strcmp(ctype, "forwarded-streamlocal@openssh.com") == 0) { 1673 c = client_request_forwarded_streamlocal(ssh, ctype, rchan); 1674 } else if (strcmp(ctype, "x11") == 0) { 1675 c = client_request_x11(ssh, ctype, rchan); 1676 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) { 1677 c = client_request_agent(ssh, ctype, rchan); 1678 } 1679 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) { 1680 debug3("proxied to downstream: %s", ctype); 1681 } else if (c != NULL) { 1682 debug("confirm %s", ctype); 1683 c->remote_id = rchan; 1684 c->have_remote_id = 1; 1685 c->remote_window = rwindow; 1686 c->remote_maxpacket = rmaxpack; 1687 if (c->type != SSH_CHANNEL_CONNECTING) { 1688 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); 1689 packet_put_int(c->remote_id); 1690 packet_put_int(c->self); 1691 packet_put_int(c->local_window); 1692 packet_put_int(c->local_maxpacket); 1693 packet_send(); 1694 } 1695 } else { 1696 debug("failure %s", ctype); 1697 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); 1698 packet_put_int(rchan); 1699 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED); 1700 if (!(datafellows & SSH_BUG_OPENFAILURE)) { 1701 packet_put_cstring("open failed"); 1702 packet_put_cstring(""); 1703 } 1704 packet_send(); 1705 } 1706 free(ctype); 1707 return 0; 1708 } 1709 1710 static int 1711 client_input_channel_req(int type, u_int32_t seq, struct ssh *ssh) 1712 { 1713 Channel *c = NULL; 1714 int exitval, id, reply, success = 0; 1715 char *rtype; 1716 1717 id = packet_get_int(); 1718 c = channel_lookup(ssh, id); 1719 if (channel_proxy_upstream(c, type, seq, ssh)) 1720 return 0; 1721 rtype = packet_get_string(NULL); 1722 reply = packet_get_char(); 1723 1724 debug("client_input_channel_req: channel %d rtype %s reply %d", 1725 id, rtype, reply); 1726 1727 if (id == -1) { 1728 error("client_input_channel_req: request for channel -1"); 1729 } else if (c == NULL) { 1730 error("client_input_channel_req: channel %d: " 1731 "unknown channel", id); 1732 } else if (strcmp(rtype, "eow@openssh.com") == 0) { 1733 packet_check_eom(); 1734 chan_rcvd_eow(ssh, c); 1735 } else if (strcmp(rtype, "exit-status") == 0) { 1736 exitval = packet_get_int(); 1737 if (c->ctl_chan != -1) { 1738 mux_exit_message(ssh, c, exitval); 1739 success = 1; 1740 } else if (id == session_ident) { 1741 /* Record exit value of local session */ 1742 success = 1; 1743 exit_status = exitval; 1744 } else { 1745 /* Probably for a mux channel that has already closed */ 1746 debug("%s: no sink for exit-status on channel %d", 1747 __func__, id); 1748 } 1749 packet_check_eom(); 1750 } 1751 if (reply && c != NULL && !(c->flags & CHAN_CLOSE_SENT)) { 1752 if (!c->have_remote_id) 1753 fatal("%s: channel %d: no remote_id", 1754 __func__, c->self); 1755 packet_start(success ? 1756 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE); 1757 packet_put_int(c->remote_id); 1758 packet_send(); 1759 } 1760 free(rtype); 1761 return 0; 1762 } 1763 1764 struct hostkeys_update_ctx { 1765 /* The hostname and (optionally) IP address string for the server */ 1766 char *host_str, *ip_str; 1767 1768 /* 1769 * Keys received from the server and a flag for each indicating 1770 * whether they already exist in known_hosts. 1771 * keys_seen is filled in by hostkeys_find() and later (for new 1772 * keys) by client_global_hostkeys_private_confirm(). 1773 */ 1774 struct sshkey **keys; 1775 int *keys_seen; 1776 size_t nkeys, nnew; 1777 1778 /* 1779 * Keys that are in known_hosts, but were not present in the update 1780 * from the server (i.e. scheduled to be deleted). 1781 * Filled in by hostkeys_find(). 1782 */ 1783 struct sshkey **old_keys; 1784 size_t nold; 1785 }; 1786 1787 static void 1788 hostkeys_update_ctx_free(struct hostkeys_update_ctx *ctx) 1789 { 1790 size_t i; 1791 1792 if (ctx == NULL) 1793 return; 1794 for (i = 0; i < ctx->nkeys; i++) 1795 sshkey_free(ctx->keys[i]); 1796 free(ctx->keys); 1797 free(ctx->keys_seen); 1798 for (i = 0; i < ctx->nold; i++) 1799 sshkey_free(ctx->old_keys[i]); 1800 free(ctx->old_keys); 1801 free(ctx->host_str); 1802 free(ctx->ip_str); 1803 free(ctx); 1804 } 1805 1806 static int 1807 hostkeys_find(struct hostkey_foreach_line *l, void *_ctx) 1808 { 1809 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 1810 size_t i; 1811 struct sshkey **tmp; 1812 1813 if (l->status != HKF_STATUS_MATCHED || l->key == NULL) 1814 return 0; 1815 1816 /* Mark off keys we've already seen for this host */ 1817 for (i = 0; i < ctx->nkeys; i++) { 1818 if (sshkey_equal(l->key, ctx->keys[i])) { 1819 debug3("%s: found %s key at %s:%ld", __func__, 1820 sshkey_ssh_name(ctx->keys[i]), l->path, l->linenum); 1821 ctx->keys_seen[i] = 1; 1822 return 0; 1823 } 1824 } 1825 /* This line contained a key that not offered by the server */ 1826 debug3("%s: deprecated %s key at %s:%ld", __func__, 1827 sshkey_ssh_name(l->key), l->path, l->linenum); 1828 if ((tmp = recallocarray(ctx->old_keys, ctx->nold, ctx->nold + 1, 1829 sizeof(*ctx->old_keys))) == NULL) 1830 fatal("%s: recallocarray failed nold = %zu", 1831 __func__, ctx->nold); 1832 ctx->old_keys = tmp; 1833 ctx->old_keys[ctx->nold++] = l->key; 1834 l->key = NULL; 1835 1836 return 0; 1837 } 1838 1839 static void 1840 update_known_hosts(struct hostkeys_update_ctx *ctx) 1841 { 1842 int r, was_raw = 0; 1843 int loglevel = options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK ? 1844 SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_VERBOSE; 1845 char *fp, *response; 1846 size_t i; 1847 1848 for (i = 0; i < ctx->nkeys; i++) { 1849 if (ctx->keys_seen[i] != 2) 1850 continue; 1851 if ((fp = sshkey_fingerprint(ctx->keys[i], 1852 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 1853 fatal("%s: sshkey_fingerprint failed", __func__); 1854 do_log2(loglevel, "Learned new hostkey: %s %s", 1855 sshkey_type(ctx->keys[i]), fp); 1856 free(fp); 1857 } 1858 for (i = 0; i < ctx->nold; i++) { 1859 if ((fp = sshkey_fingerprint(ctx->old_keys[i], 1860 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 1861 fatal("%s: sshkey_fingerprint failed", __func__); 1862 do_log2(loglevel, "Deprecating obsolete hostkey: %s %s", 1863 sshkey_type(ctx->old_keys[i]), fp); 1864 free(fp); 1865 } 1866 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) { 1867 if (get_saved_tio() != NULL) { 1868 leave_raw_mode(1); 1869 was_raw = 1; 1870 } 1871 response = NULL; 1872 for (i = 0; !quit_pending && i < 3; i++) { 1873 free(response); 1874 response = read_passphrase("Accept updated hostkeys? " 1875 "(yes/no): ", RP_ECHO); 1876 if (strcasecmp(response, "yes") == 0) 1877 break; 1878 else if (quit_pending || response == NULL || 1879 strcasecmp(response, "no") == 0) { 1880 options.update_hostkeys = 0; 1881 break; 1882 } else { 1883 do_log2(loglevel, "Please enter " 1884 "\"yes\" or \"no\""); 1885 } 1886 } 1887 if (quit_pending || i >= 3 || response == NULL) 1888 options.update_hostkeys = 0; 1889 free(response); 1890 if (was_raw) 1891 enter_raw_mode(1); 1892 } 1893 1894 /* 1895 * Now that all the keys are verified, we can go ahead and replace 1896 * them in known_hosts (assuming SSH_UPDATE_HOSTKEYS_ASK didn't 1897 * cancel the operation). 1898 */ 1899 if (options.update_hostkeys != 0 && 1900 (r = hostfile_replace_entries(options.user_hostfiles[0], 1901 ctx->host_str, ctx->ip_str, ctx->keys, ctx->nkeys, 1902 options.hash_known_hosts, 0, 1903 options.fingerprint_hash)) != 0) 1904 error("%s: hostfile_replace_entries failed: %s", 1905 __func__, ssh_err(r)); 1906 } 1907 1908 static void 1909 client_global_hostkeys_private_confirm(struct ssh *ssh, int type, 1910 u_int32_t seq, void *_ctx) 1911 { 1912 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 1913 size_t i, ndone; 1914 struct sshbuf *signdata; 1915 int r; 1916 const u_char *sig; 1917 size_t siglen; 1918 1919 if (ctx->nnew == 0) 1920 fatal("%s: ctx->nnew == 0", __func__); /* sanity */ 1921 if (type != SSH2_MSG_REQUEST_SUCCESS) { 1922 error("Server failed to confirm ownership of " 1923 "private host keys"); 1924 hostkeys_update_ctx_free(ctx); 1925 return; 1926 } 1927 if ((signdata = sshbuf_new()) == NULL) 1928 fatal("%s: sshbuf_new failed", __func__); 1929 /* Don't want to accidentally accept an unbound signature */ 1930 if (ssh->kex->session_id_len == 0) 1931 fatal("%s: ssh->kex->session_id_len == 0", __func__); 1932 /* 1933 * Expect a signature for each of the ctx->nnew private keys we 1934 * haven't seen before. They will be in the same order as the 1935 * ctx->keys where the corresponding ctx->keys_seen[i] == 0. 1936 */ 1937 for (ndone = i = 0; i < ctx->nkeys; i++) { 1938 if (ctx->keys_seen[i]) 1939 continue; 1940 /* Prepare data to be signed: session ID, unique string, key */ 1941 sshbuf_reset(signdata); 1942 if ( (r = sshbuf_put_cstring(signdata, 1943 "hostkeys-prove-00@openssh.com")) != 0 || 1944 (r = sshbuf_put_string(signdata, ssh->kex->session_id, 1945 ssh->kex->session_id_len)) != 0 || 1946 (r = sshkey_puts(ctx->keys[i], signdata)) != 0) 1947 fatal("%s: failed to prepare signature: %s", 1948 __func__, ssh_err(r)); 1949 /* Extract and verify signature */ 1950 if ((r = sshpkt_get_string_direct(ssh, &sig, &siglen)) != 0) { 1951 error("%s: couldn't parse message: %s", 1952 __func__, ssh_err(r)); 1953 goto out; 1954 } 1955 if ((r = sshkey_verify(ctx->keys[i], sig, siglen, 1956 sshbuf_ptr(signdata), sshbuf_len(signdata), 0)) != 0) { 1957 error("%s: server gave bad signature for %s key %zu", 1958 __func__, sshkey_type(ctx->keys[i]), i); 1959 goto out; 1960 } 1961 /* Key is good. Mark it as 'seen' */ 1962 ctx->keys_seen[i] = 2; 1963 ndone++; 1964 } 1965 if (ndone != ctx->nnew) 1966 fatal("%s: ndone != ctx->nnew (%zu / %zu)", __func__, 1967 ndone, ctx->nnew); /* Shouldn't happen */ 1968 ssh_packet_check_eom(ssh); 1969 1970 /* Make the edits to known_hosts */ 1971 update_known_hosts(ctx); 1972 out: 1973 hostkeys_update_ctx_free(ctx); 1974 } 1975 1976 /* 1977 * Returns non-zero if the key is accepted by HostkeyAlgorithms. 1978 * Made slightly less trivial by the multiple RSA signature algorithm names. 1979 */ 1980 static int 1981 key_accepted_by_hostkeyalgs(const struct sshkey *key) 1982 { 1983 const char *ktype = sshkey_ssh_name(key); 1984 const char *hostkeyalgs = options.hostkeyalgorithms != NULL ? 1985 options.hostkeyalgorithms : KEX_DEFAULT_PK_ALG; 1986 1987 if (key == NULL || key->type == KEY_UNSPEC) 1988 return 0; 1989 if (key->type == KEY_RSA && 1990 (match_pattern_list("rsa-sha2-256", hostkeyalgs, 0) == 1 || 1991 match_pattern_list("rsa-sha2-512", hostkeyalgs, 0) == 1)) 1992 return 1; 1993 return match_pattern_list(ktype, hostkeyalgs, 0) == 1; 1994 } 1995 1996 /* 1997 * Handle hostkeys-00@openssh.com global request to inform the client of all 1998 * the server's hostkeys. The keys are checked against the user's 1999 * HostkeyAlgorithms preference before they are accepted. 2000 */ 2001 static int 2002 client_input_hostkeys(void) 2003 { 2004 struct ssh *ssh = active_state; /* XXX */ 2005 const u_char *blob = NULL; 2006 size_t i, len = 0; 2007 struct sshbuf *buf = NULL; 2008 struct sshkey *key = NULL, **tmp; 2009 int r; 2010 char *fp; 2011 static int hostkeys_seen = 0; /* XXX use struct ssh */ 2012 extern struct sockaddr_storage hostaddr; /* XXX from ssh.c */ 2013 struct hostkeys_update_ctx *ctx = NULL; 2014 2015 if (hostkeys_seen) 2016 fatal("%s: server already sent hostkeys", __func__); 2017 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK && 2018 options.batch_mode) 2019 return 1; /* won't ask in batchmode, so don't even try */ 2020 if (!options.update_hostkeys || options.num_user_hostfiles <= 0) 2021 return 1; 2022 2023 ctx = xcalloc(1, sizeof(*ctx)); 2024 while (ssh_packet_remaining(ssh) > 0) { 2025 sshkey_free(key); 2026 key = NULL; 2027 if ((r = sshpkt_get_string_direct(ssh, &blob, &len)) != 0) { 2028 error("%s: couldn't parse message: %s", 2029 __func__, ssh_err(r)); 2030 goto out; 2031 } 2032 if ((r = sshkey_from_blob(blob, len, &key)) != 0) { 2033 error("%s: parse key: %s", __func__, ssh_err(r)); 2034 goto out; 2035 } 2036 fp = sshkey_fingerprint(key, options.fingerprint_hash, 2037 SSH_FP_DEFAULT); 2038 debug3("%s: received %s key %s", __func__, 2039 sshkey_type(key), fp); 2040 free(fp); 2041 2042 if (!key_accepted_by_hostkeyalgs(key)) { 2043 debug3("%s: %s key not permitted by HostkeyAlgorithms", 2044 __func__, sshkey_ssh_name(key)); 2045 continue; 2046 } 2047 /* Skip certs */ 2048 if (sshkey_is_cert(key)) { 2049 debug3("%s: %s key is a certificate; skipping", 2050 __func__, sshkey_ssh_name(key)); 2051 continue; 2052 } 2053 /* Ensure keys are unique */ 2054 for (i = 0; i < ctx->nkeys; i++) { 2055 if (sshkey_equal(key, ctx->keys[i])) { 2056 error("%s: received duplicated %s host key", 2057 __func__, sshkey_ssh_name(key)); 2058 goto out; 2059 } 2060 } 2061 /* Key is good, record it */ 2062 if ((tmp = recallocarray(ctx->keys, ctx->nkeys, ctx->nkeys + 1, 2063 sizeof(*ctx->keys))) == NULL) 2064 fatal("%s: recallocarray failed nkeys = %zu", 2065 __func__, ctx->nkeys); 2066 ctx->keys = tmp; 2067 ctx->keys[ctx->nkeys++] = key; 2068 key = NULL; 2069 } 2070 2071 if (ctx->nkeys == 0) { 2072 debug("%s: server sent no hostkeys", __func__); 2073 goto out; 2074 } 2075 2076 if ((ctx->keys_seen = calloc(ctx->nkeys, 2077 sizeof(*ctx->keys_seen))) == NULL) 2078 fatal("%s: calloc failed", __func__); 2079 2080 get_hostfile_hostname_ipaddr(host, 2081 options.check_host_ip ? (struct sockaddr *)&hostaddr : NULL, 2082 options.port, &ctx->host_str, 2083 options.check_host_ip ? &ctx->ip_str : NULL); 2084 2085 /* Find which keys we already know about. */ 2086 if ((r = hostkeys_foreach(options.user_hostfiles[0], hostkeys_find, 2087 ctx, ctx->host_str, ctx->ip_str, 2088 HKF_WANT_PARSE_KEY|HKF_WANT_MATCH)) != 0) { 2089 error("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r)); 2090 goto out; 2091 } 2092 2093 /* Figure out if we have any new keys to add */ 2094 ctx->nnew = 0; 2095 for (i = 0; i < ctx->nkeys; i++) { 2096 if (!ctx->keys_seen[i]) 2097 ctx->nnew++; 2098 } 2099 2100 debug3("%s: %zu keys from server: %zu new, %zu retained. %zu to remove", 2101 __func__, ctx->nkeys, ctx->nnew, ctx->nkeys - ctx->nnew, ctx->nold); 2102 2103 if (ctx->nnew == 0 && ctx->nold != 0) { 2104 /* We have some keys to remove. Just do it. */ 2105 update_known_hosts(ctx); 2106 } else if (ctx->nnew != 0) { 2107 /* 2108 * We have received hitherto-unseen keys from the server. 2109 * Ask the server to confirm ownership of the private halves. 2110 */ 2111 debug3("%s: asking server to prove ownership for %zu keys", 2112 __func__, ctx->nnew); 2113 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 2114 (r = sshpkt_put_cstring(ssh, 2115 "hostkeys-prove-00@openssh.com")) != 0 || 2116 (r = sshpkt_put_u8(ssh, 1)) != 0) /* bool: want reply */ 2117 fatal("%s: cannot prepare packet: %s", 2118 __func__, ssh_err(r)); 2119 if ((buf = sshbuf_new()) == NULL) 2120 fatal("%s: sshbuf_new", __func__); 2121 for (i = 0; i < ctx->nkeys; i++) { 2122 if (ctx->keys_seen[i]) 2123 continue; 2124 sshbuf_reset(buf); 2125 if ((r = sshkey_putb(ctx->keys[i], buf)) != 0) 2126 fatal("%s: sshkey_putb: %s", 2127 __func__, ssh_err(r)); 2128 if ((r = sshpkt_put_stringb(ssh, buf)) != 0) 2129 fatal("%s: sshpkt_put_string: %s", 2130 __func__, ssh_err(r)); 2131 } 2132 if ((r = sshpkt_send(ssh)) != 0) 2133 fatal("%s: sshpkt_send: %s", __func__, ssh_err(r)); 2134 client_register_global_confirm( 2135 client_global_hostkeys_private_confirm, ctx); 2136 ctx = NULL; /* will be freed in callback */ 2137 } 2138 2139 /* Success */ 2140 out: 2141 hostkeys_update_ctx_free(ctx); 2142 sshkey_free(key); 2143 sshbuf_free(buf); 2144 /* 2145 * NB. Return success for all cases. The server doesn't need to know 2146 * what the client does with its hosts file. 2147 */ 2148 return 1; 2149 } 2150 2151 static int 2152 client_input_global_request(int type, u_int32_t seq, struct ssh *ssh) 2153 { 2154 char *rtype; 2155 int want_reply; 2156 int success = 0; 2157 2158 rtype = packet_get_cstring(NULL); 2159 want_reply = packet_get_char(); 2160 debug("client_input_global_request: rtype %s want_reply %d", 2161 rtype, want_reply); 2162 if (strcmp(rtype, "hostkeys-00@openssh.com") == 0) 2163 success = client_input_hostkeys(); 2164 if (want_reply) { 2165 packet_start(success ? 2166 SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE); 2167 packet_send(); 2168 packet_write_wait(); 2169 } 2170 free(rtype); 2171 return 0; 2172 } 2173 2174 void 2175 client_session2_setup(struct ssh *ssh, int id, int want_tty, int want_subsystem, 2176 const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env) 2177 { 2178 int len; 2179 Channel *c = NULL; 2180 2181 debug2("%s: id %d", __func__, id); 2182 2183 if ((c = channel_lookup(ssh, id)) == NULL) 2184 fatal("%s: channel %d: unknown channel", __func__, id); 2185 2186 packet_set_interactive(want_tty, 2187 options.ip_qos_interactive, options.ip_qos_bulk); 2188 2189 if (want_tty) { 2190 struct winsize ws; 2191 2192 /* Store window size in the packet. */ 2193 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0) 2194 memset(&ws, 0, sizeof(ws)); 2195 2196 channel_request_start(ssh, id, "pty-req", 1); 2197 client_expect_confirm(ssh, id, "PTY allocation", CONFIRM_TTY); 2198 packet_put_cstring(term != NULL ? term : ""); 2199 packet_put_int((u_int)ws.ws_col); 2200 packet_put_int((u_int)ws.ws_row); 2201 packet_put_int((u_int)ws.ws_xpixel); 2202 packet_put_int((u_int)ws.ws_ypixel); 2203 if (tiop == NULL) 2204 tiop = get_saved_tio(); 2205 tty_make_modes(-1, tiop); 2206 packet_send(); 2207 /* XXX wait for reply */ 2208 c->client_tty = 1; 2209 } 2210 2211 /* Transfer any environment variables from client to server */ 2212 if (options.num_send_env != 0 && env != NULL) { 2213 int i, j, matched; 2214 char *name, *val; 2215 2216 debug("Sending environment."); 2217 for (i = 0; env[i] != NULL; i++) { 2218 /* Split */ 2219 name = xstrdup(env[i]); 2220 if ((val = strchr(name, '=')) == NULL) { 2221 free(name); 2222 continue; 2223 } 2224 *val++ = '\0'; 2225 2226 matched = 0; 2227 for (j = 0; j < options.num_send_env; j++) { 2228 if (match_pattern(name, options.send_env[j])) { 2229 matched = 1; 2230 break; 2231 } 2232 } 2233 if (!matched) { 2234 debug3("Ignored env %s", name); 2235 free(name); 2236 continue; 2237 } 2238 2239 debug("Sending env %s = %s", name, val); 2240 channel_request_start(ssh, id, "env", 0); 2241 packet_put_cstring(name); 2242 packet_put_cstring(val); 2243 packet_send(); 2244 free(name); 2245 } 2246 } 2247 2248 len = buffer_len(cmd); 2249 if (len > 0) { 2250 if (len > 900) 2251 len = 900; 2252 if (want_subsystem) { 2253 debug("Sending subsystem: %.*s", 2254 len, (u_char*)buffer_ptr(cmd)); 2255 channel_request_start(ssh, id, "subsystem", 1); 2256 client_expect_confirm(ssh, id, "subsystem", 2257 CONFIRM_CLOSE); 2258 } else { 2259 debug("Sending command: %.*s", 2260 len, (u_char*)buffer_ptr(cmd)); 2261 channel_request_start(ssh, id, "exec", 1); 2262 client_expect_confirm(ssh, id, "exec", CONFIRM_CLOSE); 2263 } 2264 packet_put_string(buffer_ptr(cmd), buffer_len(cmd)); 2265 packet_send(); 2266 } else { 2267 channel_request_start(ssh, id, "shell", 1); 2268 client_expect_confirm(ssh, id, "shell", CONFIRM_CLOSE); 2269 packet_send(); 2270 } 2271 } 2272 2273 static void 2274 client_init_dispatch(void) 2275 { 2276 dispatch_init(&dispatch_protocol_error); 2277 2278 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); 2279 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); 2280 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); 2281 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); 2282 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open); 2283 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 2284 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 2285 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req); 2286 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); 2287 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm); 2288 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm); 2289 dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request); 2290 2291 /* rekeying */ 2292 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); 2293 2294 /* global request reply messages */ 2295 dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply); 2296 dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply); 2297 } 2298 2299 void 2300 client_stop_mux(void) 2301 { 2302 if (options.control_path != NULL && muxserver_sock != -1) 2303 unlink(options.control_path); 2304 /* 2305 * If we are in persist mode, or don't have a shell, signal that we 2306 * should close when all active channels are closed. 2307 */ 2308 if (options.control_persist || no_shell_flag) { 2309 session_closed = 1; 2310 setproctitle("[stopped mux]"); 2311 } 2312 } 2313 2314 /* client specific fatal cleanup */ 2315 void 2316 cleanup_exit(int i) 2317 { 2318 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 2319 leave_non_blocking(); 2320 if (options.control_path != NULL && muxserver_sock != -1) 2321 unlink(options.control_path); 2322 ssh_kill_proxy_command(); 2323 _exit(i); 2324 } 2325