1 /* $OpenBSD: clientloop.c,v 1.318 2018/09/21 12:46:22 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 "sshbuf.h" 87 #include "compat.h" 88 #include "channels.h" 89 #include "dispatch.h" 90 #include "sshkey.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 struct sshbuf *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, struct sshbuf *); 184 185 /* Restores stdin to blocking mode. */ 186 187 static void 188 leave_non_blocking(void) 189 { 190 if (in_non_blocking_mode) { 191 unset_nonblock(fileno(stdin)); 192 in_non_blocking_mode = 0; 193 } 194 } 195 196 /* 197 * Signal handler for the window change signal (SIGWINCH). This just sets a 198 * flag indicating that the window has changed. 199 */ 200 /*ARGSUSED */ 201 static void 202 window_change_handler(int sig) 203 { 204 received_window_change_signal = 1; 205 } 206 207 /* 208 * Signal handler for signals that cause the program to terminate. These 209 * signals must be trapped to restore terminal modes. 210 */ 211 /*ARGSUSED */ 212 static void 213 signal_handler(int sig) 214 { 215 received_signal = sig; 216 quit_pending = 1; 217 } 218 219 /* 220 * Sets control_persist_exit_time to the absolute time when the 221 * backgrounded control master should exit due to expiry of the 222 * ControlPersist timeout. Sets it to 0 if we are not a backgrounded 223 * control master process, or if there is no ControlPersist timeout. 224 */ 225 static void 226 set_control_persist_exit_time(struct ssh *ssh) 227 { 228 if (muxserver_sock == -1 || !options.control_persist 229 || options.control_persist_timeout == 0) { 230 /* not using a ControlPersist timeout */ 231 control_persist_exit_time = 0; 232 } else if (channel_still_open(ssh)) { 233 /* some client connections are still open */ 234 if (control_persist_exit_time > 0) 235 debug2("%s: cancel scheduled exit", __func__); 236 control_persist_exit_time = 0; 237 } else if (control_persist_exit_time <= 0) { 238 /* a client connection has recently closed */ 239 control_persist_exit_time = monotime() + 240 (time_t)options.control_persist_timeout; 241 debug2("%s: schedule exit in %d seconds", __func__, 242 options.control_persist_timeout); 243 } 244 /* else we are already counting down to the timeout */ 245 } 246 247 #define SSH_X11_VALID_DISPLAY_CHARS ":/.-_" 248 static int 249 client_x11_display_valid(const char *display) 250 { 251 size_t i, dlen; 252 253 if (display == NULL) 254 return 0; 255 256 dlen = strlen(display); 257 for (i = 0; i < dlen; i++) { 258 if (!isalnum((u_char)display[i]) && 259 strchr(SSH_X11_VALID_DISPLAY_CHARS, display[i]) == NULL) { 260 debug("Invalid character '%c' in DISPLAY", display[i]); 261 return 0; 262 } 263 } 264 return 1; 265 } 266 267 #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1" 268 #define X11_TIMEOUT_SLACK 60 269 int 270 client_x11_get_proto(struct ssh *ssh, const char *display, 271 const char *xauth_path, u_int trusted, u_int timeout, 272 char **_proto, char **_data) 273 { 274 char *cmd, line[512], xdisplay[512]; 275 char xauthfile[PATH_MAX], xauthdir[PATH_MAX]; 276 static char proto[512], data[512]; 277 FILE *f; 278 int got_data = 0, generated = 0, do_unlink = 0, r; 279 struct stat st; 280 u_int now, x11_timeout_real; 281 282 *_proto = proto; 283 *_data = data; 284 proto[0] = data[0] = xauthfile[0] = xauthdir[0] = '\0'; 285 286 if (!client_x11_display_valid(display)) { 287 if (display != NULL) 288 logit("DISPLAY \"%s\" invalid; disabling X11 forwarding", 289 display); 290 return -1; 291 } 292 if (xauth_path != NULL && stat(xauth_path, &st) == -1) { 293 debug("No xauth program."); 294 xauth_path = NULL; 295 } 296 297 if (xauth_path != NULL) { 298 /* 299 * Handle FamilyLocal case where $DISPLAY does 300 * not match an authorization entry. For this we 301 * just try "xauth list unix:displaynum.screennum". 302 * XXX: "localhost" match to determine FamilyLocal 303 * is not perfect. 304 */ 305 if (strncmp(display, "localhost:", 10) == 0) { 306 if ((r = snprintf(xdisplay, sizeof(xdisplay), "unix:%s", 307 display + 10)) < 0 || 308 (size_t)r >= sizeof(xdisplay)) { 309 error("%s: display name too long", __func__); 310 return -1; 311 } 312 display = xdisplay; 313 } 314 if (trusted == 0) { 315 /* 316 * Generate an untrusted X11 auth cookie. 317 * 318 * The authentication cookie should briefly outlive 319 * ssh's willingness to forward X11 connections to 320 * avoid nasty fail-open behaviour in the X server. 321 */ 322 mktemp_proto(xauthdir, sizeof(xauthdir)); 323 if (mkdtemp(xauthdir) == NULL) { 324 error("%s: mkdtemp: %s", 325 __func__, strerror(errno)); 326 return -1; 327 } 328 do_unlink = 1; 329 if ((r = snprintf(xauthfile, sizeof(xauthfile), 330 "%s/xauthfile", xauthdir)) < 0 || 331 (size_t)r >= sizeof(xauthfile)) { 332 error("%s: xauthfile path too long", __func__); 333 unlink(xauthfile); 334 rmdir(xauthdir); 335 return -1; 336 } 337 338 if (timeout == 0) { 339 /* auth doesn't time out */ 340 xasprintf(&cmd, "%s -f %s generate %s %s " 341 "untrusted 2>%s", 342 xauth_path, xauthfile, display, 343 SSH_X11_PROTO, _PATH_DEVNULL); 344 } else { 345 /* Add some slack to requested expiry */ 346 if (timeout < UINT_MAX - X11_TIMEOUT_SLACK) 347 x11_timeout_real = timeout + 348 X11_TIMEOUT_SLACK; 349 else { 350 /* Don't overflow on long timeouts */ 351 x11_timeout_real = UINT_MAX; 352 } 353 xasprintf(&cmd, "%s -f %s generate %s %s " 354 "untrusted timeout %u 2>%s", 355 xauth_path, xauthfile, display, 356 SSH_X11_PROTO, x11_timeout_real, 357 _PATH_DEVNULL); 358 } 359 debug2("%s: %s", __func__, cmd); 360 361 if (timeout != 0 && x11_refuse_time == 0) { 362 now = monotime() + 1; 363 if (UINT_MAX - timeout < now) 364 x11_refuse_time = UINT_MAX; 365 else 366 x11_refuse_time = now + timeout; 367 channel_set_x11_refuse_time(ssh, 368 x11_refuse_time); 369 } 370 if (system(cmd) == 0) 371 generated = 1; 372 free(cmd); 373 } 374 375 /* 376 * When in untrusted mode, we read the cookie only if it was 377 * successfully generated as an untrusted one in the step 378 * above. 379 */ 380 if (trusted || generated) { 381 xasprintf(&cmd, 382 "%s %s%s list %s 2>" _PATH_DEVNULL, 383 xauth_path, 384 generated ? "-f " : "" , 385 generated ? xauthfile : "", 386 display); 387 debug2("x11_get_proto: %s", cmd); 388 f = popen(cmd, "r"); 389 if (f && fgets(line, sizeof(line), f) && 390 sscanf(line, "%*s %511s %511s", proto, data) == 2) 391 got_data = 1; 392 if (f) 393 pclose(f); 394 free(cmd); 395 } 396 } 397 398 if (do_unlink) { 399 unlink(xauthfile); 400 rmdir(xauthdir); 401 } 402 403 /* Don't fall back to fake X11 data for untrusted forwarding */ 404 if (!trusted && !got_data) { 405 error("Warning: untrusted X11 forwarding setup failed: " 406 "xauth key data not generated"); 407 return -1; 408 } 409 410 /* 411 * If we didn't get authentication data, just make up some 412 * data. The forwarding code will check the validity of the 413 * response anyway, and substitute this data. The X11 414 * server, however, will ignore this fake data and use 415 * whatever authentication mechanisms it was using otherwise 416 * for the local connection. 417 */ 418 if (!got_data) { 419 u_int8_t rnd[16]; 420 u_int i; 421 422 logit("Warning: No xauth data; " 423 "using fake authentication data for X11 forwarding."); 424 strlcpy(proto, SSH_X11_PROTO, sizeof proto); 425 arc4random_buf(rnd, sizeof(rnd)); 426 for (i = 0; i < sizeof(rnd); i++) { 427 snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", 428 rnd[i]); 429 } 430 } 431 432 return 0; 433 } 434 435 /* 436 * Checks if the client window has changed, and sends a packet about it to 437 * the server if so. The actual change is detected elsewhere (by a software 438 * interrupt on Unix); this just checks the flag and sends a message if 439 * appropriate. 440 */ 441 442 static void 443 client_check_window_change(struct ssh *ssh) 444 { 445 if (!received_window_change_signal) 446 return; 447 /** XXX race */ 448 received_window_change_signal = 0; 449 450 debug2("%s: changed", __func__); 451 452 channel_send_window_changes(ssh); 453 } 454 455 static int 456 client_global_request_reply(int type, u_int32_t seq, struct ssh *ssh) 457 { 458 struct global_confirm *gc; 459 460 if ((gc = TAILQ_FIRST(&global_confirms)) == NULL) 461 return 0; 462 if (gc->cb != NULL) 463 gc->cb(ssh, type, seq, gc->ctx); 464 if (--gc->ref_count <= 0) { 465 TAILQ_REMOVE(&global_confirms, gc, entry); 466 explicit_bzero(gc, sizeof(*gc)); 467 free(gc); 468 } 469 470 packet_set_alive_timeouts(0); 471 return 0; 472 } 473 474 static void 475 server_alive_check(void) 476 { 477 if (packet_inc_alive_timeouts() > options.server_alive_count_max) { 478 logit("Timeout, server %s not responding.", host); 479 cleanup_exit(255); 480 } 481 packet_start(SSH2_MSG_GLOBAL_REQUEST); 482 packet_put_cstring("keepalive@openssh.com"); 483 packet_put_char(1); /* boolean: want reply */ 484 packet_send(); 485 /* Insert an empty placeholder to maintain ordering */ 486 client_register_global_confirm(NULL, NULL); 487 } 488 489 /* 490 * Waits until the client can do something (some data becomes available on 491 * one of the file descriptors). 492 */ 493 static void 494 client_wait_until_can_do_something(struct ssh *ssh, 495 fd_set **readsetp, fd_set **writesetp, 496 int *maxfdp, u_int *nallocp, int rekeying) 497 { 498 struct timeval tv, *tvp; 499 int timeout_secs; 500 time_t minwait_secs = 0, server_alive_time = 0, now = monotime(); 501 int r, ret; 502 503 /* Add any selections by the channel mechanism. */ 504 channel_prepare_select(active_state, readsetp, writesetp, maxfdp, 505 nallocp, &minwait_secs); 506 507 /* channel_prepare_select could have closed the last channel */ 508 if (session_closed && !channel_still_open(ssh) && 509 !packet_have_data_to_write()) { 510 /* clear mask since we did not call select() */ 511 memset(*readsetp, 0, *nallocp); 512 memset(*writesetp, 0, *nallocp); 513 return; 514 } 515 516 FD_SET(connection_in, *readsetp); 517 518 /* Select server connection if have data to write to the server. */ 519 if (packet_have_data_to_write()) 520 FD_SET(connection_out, *writesetp); 521 522 /* 523 * Wait for something to happen. This will suspend the process until 524 * some selected descriptor can be read, written, or has some other 525 * event pending, or a timeout expires. 526 */ 527 528 timeout_secs = INT_MAX; /* we use INT_MAX to mean no timeout */ 529 if (options.server_alive_interval > 0) { 530 timeout_secs = options.server_alive_interval; 531 server_alive_time = now + options.server_alive_interval; 532 } 533 if (options.rekey_interval > 0 && !rekeying) 534 timeout_secs = MINIMUM(timeout_secs, packet_get_rekey_timeout()); 535 set_control_persist_exit_time(ssh); 536 if (control_persist_exit_time > 0) { 537 timeout_secs = MINIMUM(timeout_secs, 538 control_persist_exit_time - now); 539 if (timeout_secs < 0) 540 timeout_secs = 0; 541 } 542 if (minwait_secs != 0) 543 timeout_secs = MINIMUM(timeout_secs, (int)minwait_secs); 544 if (timeout_secs == INT_MAX) 545 tvp = NULL; 546 else { 547 tv.tv_sec = timeout_secs; 548 tv.tv_usec = 0; 549 tvp = &tv; 550 } 551 552 ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp); 553 if (ret < 0) { 554 /* 555 * We have to clear the select masks, because we return. 556 * We have to return, because the mainloop checks for the flags 557 * set by the signal handlers. 558 */ 559 memset(*readsetp, 0, *nallocp); 560 memset(*writesetp, 0, *nallocp); 561 562 if (errno == EINTR) 563 return; 564 /* Note: we might still have data in the buffers. */ 565 if ((r = sshbuf_putf(stderr_buffer, 566 "select: %s\r\n", strerror(errno))) != 0) 567 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 568 quit_pending = 1; 569 } else if (ret == 0) { 570 /* 571 * Timeout. Could have been either keepalive or rekeying. 572 * Keepalive we check here, rekeying is checked in clientloop. 573 */ 574 if (server_alive_time != 0 && server_alive_time <= monotime()) 575 server_alive_check(); 576 } 577 578 } 579 580 static void 581 client_suspend_self(struct sshbuf *bin, struct sshbuf *bout, struct sshbuf *berr) 582 { 583 /* Flush stdout and stderr buffers. */ 584 if (sshbuf_len(bout) > 0) 585 atomicio(vwrite, fileno(stdout), sshbuf_mutable_ptr(bout), 586 sshbuf_len(bout)); 587 if (sshbuf_len(berr) > 0) 588 atomicio(vwrite, fileno(stderr), sshbuf_mutable_ptr(berr), 589 sshbuf_len(berr)); 590 591 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 592 593 sshbuf_reset(bin); 594 sshbuf_reset(bout); 595 sshbuf_reset(berr); 596 597 /* Send the suspend signal to the program itself. */ 598 kill(getpid(), SIGTSTP); 599 600 /* Reset window sizes in case they have changed */ 601 received_window_change_signal = 1; 602 603 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 604 } 605 606 static void 607 client_process_net_input(fd_set *readset) 608 { 609 char buf[8192]; 610 int r, len; 611 612 /* 613 * Read input from the server, and add any such data to the buffer of 614 * the packet subsystem. 615 */ 616 if (FD_ISSET(connection_in, readset)) { 617 /* Read as much as possible. */ 618 len = read(connection_in, buf, sizeof(buf)); 619 if (len == 0) { 620 /* 621 * Received EOF. The remote host has closed the 622 * connection. 623 */ 624 if ((r = sshbuf_putf(stderr_buffer, 625 "Connection to %.300s closed by remote host.\r\n", 626 host)) != 0) 627 fatal("%s: buffer error: %s", 628 __func__, ssh_err(r)); 629 quit_pending = 1; 630 return; 631 } 632 /* 633 * There is a kernel bug on Solaris that causes select to 634 * sometimes wake up even though there is no data available. 635 */ 636 if (len < 0 && (errno == EAGAIN || errno == EINTR)) 637 len = 0; 638 639 if (len < 0) { 640 /* 641 * An error has encountered. Perhaps there is a 642 * network problem. 643 */ 644 if ((r = sshbuf_putf(stderr_buffer, 645 "Read from remote host %.300s: %.100s\r\n", 646 host, strerror(errno))) != 0) 647 fatal("%s: buffer error: %s", 648 __func__, ssh_err(r)); 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 r, 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 suppress 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 if ((r = sshbuf_put(c->extended, errmsg, 697 strlen(errmsg))) != 0) 698 fatal("%s: buffer error %s", __func__, 699 ssh_err(r)); 700 } else 701 error("%s", errmsg); 702 if (cr->action == CONFIRM_TTY) { 703 /* 704 * If a TTY allocation error occurred, then arrange 705 * for the correct TTY to leave raw mode. 706 */ 707 if (c->self == session_ident) 708 leave_raw_mode(0); 709 else 710 mux_tty_alloc_failed(ssh, c); 711 } else if (cr->action == CONFIRM_CLOSE) { 712 chan_read_failed(ssh, c); 713 chan_write_failed(ssh, c); 714 } 715 } 716 free(cr); 717 } 718 719 static void 720 client_abandon_status_confirm(struct ssh *ssh, Channel *c, void *ctx) 721 { 722 free(ctx); 723 } 724 725 void 726 client_expect_confirm(struct ssh *ssh, int id, const char *request, 727 enum confirm_action action) 728 { 729 struct channel_reply_ctx *cr = xcalloc(1, sizeof(*cr)); 730 731 cr->request_type = request; 732 cr->action = action; 733 734 channel_register_status_confirm(ssh, id, client_status_confirm, 735 client_abandon_status_confirm, cr); 736 } 737 738 void 739 client_register_global_confirm(global_confirm_cb *cb, void *ctx) 740 { 741 struct global_confirm *gc, *last_gc; 742 743 /* Coalesce identical callbacks */ 744 last_gc = TAILQ_LAST(&global_confirms, global_confirms); 745 if (last_gc && last_gc->cb == cb && last_gc->ctx == ctx) { 746 if (++last_gc->ref_count >= INT_MAX) 747 fatal("%s: last_gc->ref_count = %d", 748 __func__, last_gc->ref_count); 749 return; 750 } 751 752 gc = xcalloc(1, sizeof(*gc)); 753 gc->cb = cb; 754 gc->ctx = ctx; 755 gc->ref_count = 1; 756 TAILQ_INSERT_TAIL(&global_confirms, gc, entry); 757 } 758 759 static void 760 process_cmdline(struct ssh *ssh) 761 { 762 void (*handler)(int); 763 char *s, *cmd; 764 int ok, delete = 0, local = 0, remote = 0, dynamic = 0; 765 struct Forward fwd; 766 767 memset(&fwd, 0, sizeof(fwd)); 768 769 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 770 handler = signal(SIGINT, SIG_IGN); 771 cmd = s = read_passphrase("\r\nssh> ", RP_ECHO); 772 if (s == NULL) 773 goto out; 774 while (isspace((u_char)*s)) 775 s++; 776 if (*s == '-') 777 s++; /* Skip cmdline '-', if any */ 778 if (*s == '\0') 779 goto out; 780 781 if (*s == 'h' || *s == 'H' || *s == '?') { 782 logit("Commands:"); 783 logit(" -L[bind_address:]port:host:hostport " 784 "Request local forward"); 785 logit(" -R[bind_address:]port:host:hostport " 786 "Request remote forward"); 787 logit(" -D[bind_address:]port " 788 "Request dynamic forward"); 789 logit(" -KL[bind_address:]port " 790 "Cancel local forward"); 791 logit(" -KR[bind_address:]port " 792 "Cancel remote forward"); 793 logit(" -KD[bind_address:]port " 794 "Cancel dynamic forward"); 795 if (!options.permit_local_command) 796 goto out; 797 logit(" !args " 798 "Execute local command"); 799 goto out; 800 } 801 802 if (*s == '!' && options.permit_local_command) { 803 s++; 804 ssh_local_cmd(s); 805 goto out; 806 } 807 808 if (*s == 'K') { 809 delete = 1; 810 s++; 811 } 812 if (*s == 'L') 813 local = 1; 814 else if (*s == 'R') 815 remote = 1; 816 else if (*s == 'D') 817 dynamic = 1; 818 else { 819 logit("Invalid command."); 820 goto out; 821 } 822 823 while (isspace((u_char)*++s)) 824 ; 825 826 /* XXX update list of forwards in options */ 827 if (delete) { 828 /* We pass 1 for dynamicfwd to restrict to 1 or 2 fields. */ 829 if (!parse_forward(&fwd, s, 1, 0)) { 830 logit("Bad forwarding close specification."); 831 goto out; 832 } 833 if (remote) 834 ok = channel_request_rforward_cancel(ssh, &fwd) == 0; 835 else if (dynamic) 836 ok = channel_cancel_lport_listener(ssh, &fwd, 837 0, &options.fwd_opts) > 0; 838 else 839 ok = channel_cancel_lport_listener(ssh, &fwd, 840 CHANNEL_CANCEL_PORT_STATIC, 841 &options.fwd_opts) > 0; 842 if (!ok) { 843 logit("Unknown port forwarding."); 844 goto out; 845 } 846 logit("Canceled forwarding."); 847 } else { 848 if (!parse_forward(&fwd, s, dynamic, remote)) { 849 logit("Bad forwarding specification."); 850 goto out; 851 } 852 if (local || dynamic) { 853 if (!channel_setup_local_fwd_listener(ssh, &fwd, 854 &options.fwd_opts)) { 855 logit("Port forwarding failed."); 856 goto out; 857 } 858 } else { 859 if (channel_request_remote_forwarding(ssh, &fwd) < 0) { 860 logit("Port forwarding failed."); 861 goto out; 862 } 863 } 864 logit("Forwarding port."); 865 } 866 867 out: 868 signal(SIGINT, handler); 869 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 870 free(cmd); 871 free(fwd.listen_host); 872 free(fwd.listen_path); 873 free(fwd.connect_host); 874 free(fwd.connect_path); 875 } 876 877 /* reasons to suppress output of an escape command in help output */ 878 #define SUPPRESS_NEVER 0 /* never suppress, always show */ 879 #define SUPPRESS_MUXCLIENT 1 /* don't show in mux client sessions */ 880 #define SUPPRESS_MUXMASTER 2 /* don't show in mux master sessions */ 881 #define SUPPRESS_SYSLOG 4 /* don't show when logging to syslog */ 882 struct escape_help_text { 883 const char *cmd; 884 const char *text; 885 unsigned int flags; 886 }; 887 static struct escape_help_text esc_txt[] = { 888 {".", "terminate session", SUPPRESS_MUXMASTER}, 889 {".", "terminate connection (and any multiplexed sessions)", 890 SUPPRESS_MUXCLIENT}, 891 {"B", "send a BREAK to the remote system", SUPPRESS_NEVER}, 892 {"C", "open a command line", SUPPRESS_MUXCLIENT}, 893 {"R", "request rekey", SUPPRESS_NEVER}, 894 {"V/v", "decrease/increase verbosity (LogLevel)", SUPPRESS_MUXCLIENT}, 895 {"^Z", "suspend ssh", SUPPRESS_MUXCLIENT}, 896 {"#", "list forwarded connections", SUPPRESS_NEVER}, 897 {"&", "background ssh (when waiting for connections to terminate)", 898 SUPPRESS_MUXCLIENT}, 899 {"?", "this message", SUPPRESS_NEVER}, 900 }; 901 902 static void 903 print_escape_help(struct sshbuf *b, int escape_char, int mux_client, 904 int using_stderr) 905 { 906 unsigned int i, suppress_flags; 907 int r; 908 909 if ((r = sshbuf_putf(b, 910 "%c?\r\nSupported escape sequences:\r\n", escape_char)) != 0) 911 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 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 if ((r = sshbuf_putf(b, " %c%-3s - %s\r\n", 922 escape_char, esc_txt[i].cmd, esc_txt[i].text)) != 0) 923 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 924 } 925 926 if ((r = sshbuf_putf(b, 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)) != 0) 930 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 931 } 932 933 /* 934 * Process the characters one by one. 935 */ 936 static int 937 process_escapes(struct ssh *ssh, Channel *c, 938 struct sshbuf *bin, struct sshbuf *bout, struct sshbuf *berr, 939 char *buf, int len) 940 { 941 pid_t pid; 942 int r, bytes = 0; 943 u_int i; 944 u_char ch; 945 char *s; 946 struct escape_filter_ctx *efc = c->filter_ctx == NULL ? 947 NULL : (struct escape_filter_ctx *)c->filter_ctx; 948 949 if (c->filter_ctx == NULL) 950 return 0; 951 952 if (len <= 0) 953 return (0); 954 955 for (i = 0; i < (u_int)len; i++) { 956 /* Get one character at a time. */ 957 ch = buf[i]; 958 959 if (efc->escape_pending) { 960 /* We have previously seen an escape character. */ 961 /* Clear the flag now. */ 962 efc->escape_pending = 0; 963 964 /* Process the escaped character. */ 965 switch (ch) { 966 case '.': 967 /* Terminate the connection. */ 968 if ((r = sshbuf_putf(berr, "%c.\r\n", 969 efc->escape_char)) != 0) 970 fatal("%s: buffer error: %s", 971 __func__, ssh_err(r)); 972 if (c && c->ctl_chan != -1) { 973 chan_read_failed(ssh, c); 974 chan_write_failed(ssh, c); 975 if (c->detach_user) { 976 c->detach_user(ssh, 977 c->self, NULL); 978 } 979 c->type = SSH_CHANNEL_ABANDONED; 980 sshbuf_reset(c->input); 981 chan_ibuf_empty(ssh, c); 982 return 0; 983 } else 984 quit_pending = 1; 985 return -1; 986 987 case 'Z' - 64: 988 /* XXX support this for mux clients */ 989 if (c && c->ctl_chan != -1) { 990 char b[16]; 991 noescape: 992 if (ch == 'Z' - 64) 993 snprintf(b, sizeof b, "^Z"); 994 else 995 snprintf(b, sizeof b, "%c", ch); 996 if ((r = sshbuf_putf(berr, 997 "%c%s escape not available to " 998 "multiplexed sessions\r\n", 999 efc->escape_char, b)) != 0) 1000 fatal("%s: buffer error: %s", 1001 __func__, ssh_err(r)); 1002 continue; 1003 } 1004 /* Suspend the program. Inform the user */ 1005 if ((r = sshbuf_putf(berr, 1006 "%c^Z [suspend ssh]\r\n", 1007 efc->escape_char)) != 0) 1008 fatal("%s: buffer error: %s", 1009 __func__, ssh_err(r)); 1010 1011 /* Restore terminal modes and suspend. */ 1012 client_suspend_self(bin, bout, berr); 1013 1014 /* We have been continued. */ 1015 continue; 1016 1017 case 'B': 1018 if ((r = sshbuf_putf(berr, 1019 "%cB\r\n", efc->escape_char)) != 0) 1020 fatal("%s: buffer error: %s", 1021 __func__, ssh_err(r)); 1022 channel_request_start(ssh, c->self, "break", 0); 1023 if ((r = sshpkt_put_u32(ssh, 1000)) != 0 || 1024 (r = sshpkt_send(ssh)) != 0) 1025 fatal("%s: %s", __func__, 1026 ssh_err(r)); 1027 continue; 1028 1029 case 'R': 1030 if (datafellows & SSH_BUG_NOREKEY) 1031 logit("Server does not " 1032 "support re-keying"); 1033 else 1034 need_rekeying = 1; 1035 continue; 1036 1037 case 'V': 1038 /* FALLTHROUGH */ 1039 case 'v': 1040 if (c && c->ctl_chan != -1) 1041 goto noescape; 1042 if (!log_is_on_stderr()) { 1043 if ((r = sshbuf_putf(berr, 1044 "%c%c [Logging to syslog]\r\n", 1045 efc->escape_char, ch)) != 0) 1046 fatal("%s: buffer error: %s", 1047 __func__, ssh_err(r)); 1048 continue; 1049 } 1050 if (ch == 'V' && options.log_level > 1051 SYSLOG_LEVEL_QUIET) 1052 log_change_level(--options.log_level); 1053 if (ch == 'v' && options.log_level < 1054 SYSLOG_LEVEL_DEBUG3) 1055 log_change_level(++options.log_level); 1056 if ((r = sshbuf_putf(berr, 1057 "%c%c [LogLevel %s]\r\n", 1058 efc->escape_char, ch, 1059 log_level_name(options.log_level))) != 0) 1060 fatal("%s: buffer error: %s", 1061 __func__, ssh_err(r)); 1062 continue; 1063 1064 case '&': 1065 if (c && c->ctl_chan != -1) 1066 goto noescape; 1067 /* 1068 * Detach the program (continue to serve 1069 * connections, but put in background and no 1070 * more new connections). 1071 */ 1072 /* Restore tty modes. */ 1073 leave_raw_mode( 1074 options.request_tty == REQUEST_TTY_FORCE); 1075 1076 /* Stop listening for new connections. */ 1077 channel_stop_listening(ssh); 1078 1079 if ((r = sshbuf_putf(berr, 1080 "%c& [backgrounded]\n", efc->escape_char)) 1081 != 0) 1082 fatal("%s: buffer error: %s", 1083 __func__, ssh_err(r)); 1084 1085 /* Fork into background. */ 1086 pid = fork(); 1087 if (pid < 0) { 1088 error("fork: %.100s", strerror(errno)); 1089 continue; 1090 } 1091 if (pid != 0) { /* This is the parent. */ 1092 /* The parent just exits. */ 1093 exit(0); 1094 } 1095 /* The child continues serving connections. */ 1096 /* fake EOF on stdin */ 1097 if ((r = sshbuf_put_u8(bin, 4)) != 0) 1098 fatal("%s: buffer error: %s", 1099 __func__, ssh_err(r)); 1100 return -1; 1101 case '?': 1102 print_escape_help(berr, efc->escape_char, 1103 (c && c->ctl_chan != -1), 1104 log_is_on_stderr()); 1105 continue; 1106 1107 case '#': 1108 if ((r = sshbuf_putf(berr, "%c#\r\n", 1109 efc->escape_char)) != 0) 1110 fatal("%s: buffer error: %s", 1111 __func__, ssh_err(r)); 1112 s = channel_open_message(ssh); 1113 if ((r = sshbuf_put(berr, s, strlen(s))) != 0) 1114 fatal("%s: buffer error: %s", 1115 __func__, ssh_err(r)); 1116 free(s); 1117 continue; 1118 1119 case 'C': 1120 if (c && c->ctl_chan != -1) 1121 goto noescape; 1122 process_cmdline(ssh); 1123 continue; 1124 1125 default: 1126 if (ch != efc->escape_char) { 1127 if ((r = sshbuf_put_u8(bin, 1128 efc->escape_char)) != 0) 1129 fatal("%s: buffer error: %s", 1130 __func__, ssh_err(r)); 1131 bytes++; 1132 } 1133 /* Escaped characters fall through here */ 1134 break; 1135 } 1136 } else { 1137 /* 1138 * The previous character was not an escape char. 1139 * Check if this is an escape. 1140 */ 1141 if (last_was_cr && ch == efc->escape_char) { 1142 /* 1143 * It is. Set the flag and continue to 1144 * next character. 1145 */ 1146 efc->escape_pending = 1; 1147 continue; 1148 } 1149 } 1150 1151 /* 1152 * Normal character. Record whether it was a newline, 1153 * and append it to the buffer. 1154 */ 1155 last_was_cr = (ch == '\r' || ch == '\n'); 1156 if ((r = sshbuf_put_u8(bin, ch)) != 0) 1157 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1158 bytes++; 1159 } 1160 return bytes; 1161 } 1162 1163 /* 1164 * Get packets from the connection input buffer, and process them as long as 1165 * there are packets available. 1166 * 1167 * Any unknown packets received during the actual 1168 * session cause the session to terminate. This is 1169 * intended to make debugging easier since no 1170 * confirmations are sent. Any compatible protocol 1171 * extensions must be negotiated during the 1172 * preparatory phase. 1173 */ 1174 1175 static void 1176 client_process_buffered_input_packets(void) 1177 { 1178 ssh_dispatch_run_fatal(active_state, DISPATCH_NONBLOCK, &quit_pending); 1179 } 1180 1181 /* scan buf[] for '~' before sending data to the peer */ 1182 1183 /* Helper: allocate a new escape_filter_ctx and fill in its escape char */ 1184 void * 1185 client_new_escape_filter_ctx(int escape_char) 1186 { 1187 struct escape_filter_ctx *ret; 1188 1189 ret = xcalloc(1, sizeof(*ret)); 1190 ret->escape_pending = 0; 1191 ret->escape_char = escape_char; 1192 return (void *)ret; 1193 } 1194 1195 /* Free the escape filter context on channel free */ 1196 void 1197 client_filter_cleanup(struct ssh *ssh, int cid, void *ctx) 1198 { 1199 free(ctx); 1200 } 1201 1202 int 1203 client_simple_escape_filter(struct ssh *ssh, Channel *c, char *buf, int len) 1204 { 1205 if (c->extended_usage != CHAN_EXTENDED_WRITE) 1206 return 0; 1207 1208 return process_escapes(ssh, c, c->input, c->output, c->extended, 1209 buf, len); 1210 } 1211 1212 static void 1213 client_channel_closed(struct ssh *ssh, int id, void *arg) 1214 { 1215 channel_cancel_cleanup(ssh, id); 1216 session_closed = 1; 1217 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1218 } 1219 1220 /* 1221 * Implements the interactive session with the server. This is called after 1222 * the user has been authenticated, and a command has been started on the 1223 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character 1224 * used as an escape character for terminating or suspending the session. 1225 */ 1226 int 1227 client_loop(struct ssh *ssh, int have_pty, int escape_char_arg, 1228 int ssh2_chan_id) 1229 { 1230 fd_set *readset = NULL, *writeset = NULL; 1231 double start_time, total_time; 1232 int r, max_fd = 0, max_fd2 = 0, len; 1233 u_int64_t ibytes, obytes; 1234 u_int nalloc = 0; 1235 char buf[100]; 1236 1237 debug("Entering interactive session."); 1238 1239 if (options.control_master && 1240 !option_clear_or_none(options.control_path)) { 1241 debug("pledge: id"); 1242 if (pledge("stdio rpath wpath cpath unix inet dns recvfd proc exec id tty", 1243 NULL) == -1) 1244 fatal("%s pledge(): %s", __func__, strerror(errno)); 1245 1246 } else if (options.forward_x11 || options.permit_local_command) { 1247 debug("pledge: exec"); 1248 if (pledge("stdio rpath wpath cpath unix inet dns proc exec tty", 1249 NULL) == -1) 1250 fatal("%s pledge(): %s", __func__, strerror(errno)); 1251 1252 } else if (options.update_hostkeys) { 1253 debug("pledge: filesystem full"); 1254 if (pledge("stdio rpath wpath cpath unix inet dns proc tty", 1255 NULL) == -1) 1256 fatal("%s pledge(): %s", __func__, strerror(errno)); 1257 1258 } else if (!option_clear_or_none(options.proxy_command) || 1259 fork_after_authentication_flag) { 1260 debug("pledge: proc"); 1261 if (pledge("stdio cpath unix inet dns proc tty", NULL) == -1) 1262 fatal("%s pledge(): %s", __func__, strerror(errno)); 1263 1264 } else { 1265 debug("pledge: network"); 1266 if (pledge("stdio unix inet dns proc tty", NULL) == -1) 1267 fatal("%s pledge(): %s", __func__, strerror(errno)); 1268 } 1269 1270 start_time = monotime_double(); 1271 1272 /* Initialize variables. */ 1273 last_was_cr = 1; 1274 exit_status = -1; 1275 connection_in = packet_get_connection_in(); 1276 connection_out = packet_get_connection_out(); 1277 max_fd = MAXIMUM(connection_in, connection_out); 1278 1279 quit_pending = 0; 1280 1281 /* Initialize buffer. */ 1282 if ((stderr_buffer = sshbuf_new()) == NULL) 1283 fatal("%s: sshbuf_new failed", __func__); 1284 1285 client_init_dispatch(); 1286 1287 /* 1288 * Set signal handlers, (e.g. to restore non-blocking mode) 1289 * but don't overwrite SIG_IGN, matches behaviour from rsh(1) 1290 */ 1291 if (signal(SIGHUP, SIG_IGN) != SIG_IGN) 1292 signal(SIGHUP, signal_handler); 1293 if (signal(SIGINT, SIG_IGN) != SIG_IGN) 1294 signal(SIGINT, signal_handler); 1295 if (signal(SIGQUIT, SIG_IGN) != SIG_IGN) 1296 signal(SIGQUIT, signal_handler); 1297 if (signal(SIGTERM, SIG_IGN) != SIG_IGN) 1298 signal(SIGTERM, signal_handler); 1299 signal(SIGWINCH, window_change_handler); 1300 1301 if (have_pty) 1302 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1303 1304 session_ident = ssh2_chan_id; 1305 if (session_ident != -1) { 1306 if (escape_char_arg != SSH_ESCAPECHAR_NONE) { 1307 channel_register_filter(ssh, session_ident, 1308 client_simple_escape_filter, NULL, 1309 client_filter_cleanup, 1310 client_new_escape_filter_ctx( 1311 escape_char_arg)); 1312 } 1313 channel_register_cleanup(ssh, session_ident, 1314 client_channel_closed, 0); 1315 } 1316 1317 /* Main loop of the client for the interactive session mode. */ 1318 while (!quit_pending) { 1319 1320 /* Process buffered packets sent by the server. */ 1321 client_process_buffered_input_packets(); 1322 1323 if (session_closed && !channel_still_open(ssh)) 1324 break; 1325 1326 if (ssh_packet_is_rekeying(ssh)) { 1327 debug("rekeying in progress"); 1328 } else if (need_rekeying) { 1329 /* manual rekey request */ 1330 debug("need rekeying"); 1331 if ((r = kex_start_rekex(ssh)) != 0) 1332 fatal("%s: kex_start_rekex: %s", __func__, 1333 ssh_err(r)); 1334 need_rekeying = 0; 1335 } else { 1336 /* 1337 * Make packets from buffered channel data, and 1338 * enqueue them for sending to the server. 1339 */ 1340 if (packet_not_very_much_data_to_write()) 1341 channel_output_poll(ssh); 1342 1343 /* 1344 * Check if the window size has changed, and buffer a 1345 * message about it to the server if so. 1346 */ 1347 client_check_window_change(ssh); 1348 1349 if (quit_pending) 1350 break; 1351 } 1352 /* 1353 * Wait until we have something to do (something becomes 1354 * available on one of the descriptors). 1355 */ 1356 max_fd2 = max_fd; 1357 client_wait_until_can_do_something(ssh, &readset, &writeset, 1358 &max_fd2, &nalloc, ssh_packet_is_rekeying(ssh)); 1359 1360 if (quit_pending) 1361 break; 1362 1363 /* Do channel operations unless rekeying in progress. */ 1364 if (!ssh_packet_is_rekeying(ssh)) 1365 channel_after_select(ssh, readset, writeset); 1366 1367 /* Buffer input from the connection. */ 1368 client_process_net_input(readset); 1369 1370 if (quit_pending) 1371 break; 1372 1373 /* 1374 * Send as much buffered packet data as possible to the 1375 * sender. 1376 */ 1377 if (FD_ISSET(connection_out, writeset)) 1378 packet_write_poll(); 1379 1380 /* 1381 * If we are a backgrounded control master, and the 1382 * timeout has expired without any active client 1383 * connections, then quit. 1384 */ 1385 if (control_persist_exit_time > 0) { 1386 if (monotime() >= control_persist_exit_time) { 1387 debug("ControlPersist timeout expired"); 1388 break; 1389 } 1390 } 1391 } 1392 free(readset); 1393 free(writeset); 1394 1395 /* Terminate the session. */ 1396 1397 /* Stop watching for window change. */ 1398 signal(SIGWINCH, SIG_DFL); 1399 1400 packet_start(SSH2_MSG_DISCONNECT); 1401 packet_put_int(SSH2_DISCONNECT_BY_APPLICATION); 1402 packet_put_cstring("disconnected by user"); 1403 packet_put_cstring(""); /* language tag */ 1404 packet_send(); 1405 packet_write_wait(); 1406 1407 channel_free_all(ssh); 1408 1409 if (have_pty) 1410 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1411 1412 /* restore blocking io */ 1413 if (!isatty(fileno(stdin))) 1414 unset_nonblock(fileno(stdin)); 1415 if (!isatty(fileno(stdout))) 1416 unset_nonblock(fileno(stdout)); 1417 if (!isatty(fileno(stderr))) 1418 unset_nonblock(fileno(stderr)); 1419 1420 /* 1421 * If there was no shell or command requested, there will be no remote 1422 * exit status to be returned. In that case, clear error code if the 1423 * connection was deliberately terminated at this end. 1424 */ 1425 if (no_shell_flag && received_signal == SIGTERM) { 1426 received_signal = 0; 1427 exit_status = 0; 1428 } 1429 1430 if (received_signal) { 1431 verbose("Killed by signal %d.", (int) received_signal); 1432 cleanup_exit(0); 1433 } 1434 1435 /* 1436 * In interactive mode (with pseudo tty) display a message indicating 1437 * that the connection has been closed. 1438 */ 1439 if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) { 1440 if ((r = sshbuf_putf(stderr_buffer, 1441 "Connection to %.64s closed.\r\n", host)) != 0) 1442 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1443 } 1444 1445 /* Output any buffered data for stderr. */ 1446 if (sshbuf_len(stderr_buffer) > 0) { 1447 len = atomicio(vwrite, fileno(stderr), 1448 (u_char *)sshbuf_ptr(stderr_buffer), 1449 sshbuf_len(stderr_buffer)); 1450 if (len < 0 || (u_int)len != sshbuf_len(stderr_buffer)) 1451 error("Write failed flushing stderr buffer."); 1452 else if ((r = sshbuf_consume(stderr_buffer, len)) != 0) 1453 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1454 } 1455 1456 /* Clear and free any buffers. */ 1457 explicit_bzero(buf, sizeof(buf)); 1458 sshbuf_free(stderr_buffer); 1459 1460 /* Report bytes transferred, and transfer rates. */ 1461 total_time = monotime_double() - start_time; 1462 packet_get_bytes(&ibytes, &obytes); 1463 verbose("Transferred: sent %llu, received %llu bytes, in %.1f seconds", 1464 (unsigned long long)obytes, (unsigned long long)ibytes, total_time); 1465 if (total_time > 0) 1466 verbose("Bytes per second: sent %.1f, received %.1f", 1467 obytes / total_time, ibytes / total_time); 1468 /* Return the exit status of the program. */ 1469 debug("Exit status %d", exit_status); 1470 return exit_status; 1471 } 1472 1473 /*********/ 1474 1475 static Channel * 1476 client_request_forwarded_tcpip(struct ssh *ssh, const char *request_type, 1477 int rchan, u_int rwindow, u_int rmaxpack) 1478 { 1479 Channel *c = NULL; 1480 struct sshbuf *b = NULL; 1481 char *listen_address, *originator_address; 1482 u_short listen_port, originator_port; 1483 int r; 1484 1485 /* Get rest of the packet */ 1486 listen_address = packet_get_string(NULL); 1487 listen_port = packet_get_int(); 1488 originator_address = packet_get_string(NULL); 1489 originator_port = packet_get_int(); 1490 packet_check_eom(); 1491 1492 debug("%s: listen %s port %d, originator %s port %d", __func__, 1493 listen_address, listen_port, originator_address, originator_port); 1494 1495 c = channel_connect_by_listen_address(ssh, listen_address, listen_port, 1496 "forwarded-tcpip", originator_address); 1497 1498 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) { 1499 if ((b = sshbuf_new()) == NULL) { 1500 error("%s: alloc reply", __func__); 1501 goto out; 1502 } 1503 /* reconstruct and send to muxclient */ 1504 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 1505 (r = sshbuf_put_u8(b, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1506 (r = sshbuf_put_cstring(b, request_type)) != 0 || 1507 (r = sshbuf_put_u32(b, rchan)) != 0 || 1508 (r = sshbuf_put_u32(b, rwindow)) != 0 || 1509 (r = sshbuf_put_u32(b, rmaxpack)) != 0 || 1510 (r = sshbuf_put_cstring(b, listen_address)) != 0 || 1511 (r = sshbuf_put_u32(b, listen_port)) != 0 || 1512 (r = sshbuf_put_cstring(b, originator_address)) != 0 || 1513 (r = sshbuf_put_u32(b, originator_port)) != 0 || 1514 (r = sshbuf_put_stringb(c->output, b)) != 0) { 1515 error("%s: compose for muxclient %s", __func__, 1516 ssh_err(r)); 1517 goto out; 1518 } 1519 } 1520 1521 out: 1522 sshbuf_free(b); 1523 free(originator_address); 1524 free(listen_address); 1525 return c; 1526 } 1527 1528 static Channel * 1529 client_request_forwarded_streamlocal(struct ssh *ssh, 1530 const char *request_type, int rchan) 1531 { 1532 Channel *c = NULL; 1533 char *listen_path; 1534 1535 /* Get the remote path. */ 1536 listen_path = packet_get_string(NULL); 1537 /* XXX: Skip reserved field for now. */ 1538 if (packet_get_string_ptr(NULL) == NULL) 1539 fatal("%s: packet_get_string_ptr failed", __func__); 1540 packet_check_eom(); 1541 1542 debug("%s: %s", __func__, listen_path); 1543 1544 c = channel_connect_by_listen_path(ssh, listen_path, 1545 "forwarded-streamlocal@openssh.com", "forwarded-streamlocal"); 1546 free(listen_path); 1547 return c; 1548 } 1549 1550 static Channel * 1551 client_request_x11(struct ssh *ssh, const char *request_type, int rchan) 1552 { 1553 Channel *c = NULL; 1554 char *originator; 1555 u_short originator_port; 1556 int sock; 1557 1558 if (!options.forward_x11) { 1559 error("Warning: ssh server tried X11 forwarding."); 1560 error("Warning: this is probably a break-in attempt by a " 1561 "malicious server."); 1562 return NULL; 1563 } 1564 if (x11_refuse_time != 0 && (u_int)monotime() >= x11_refuse_time) { 1565 verbose("Rejected X11 connection after ForwardX11Timeout " 1566 "expired"); 1567 return NULL; 1568 } 1569 originator = packet_get_string(NULL); 1570 originator_port = packet_get_int(); 1571 packet_check_eom(); 1572 /* XXX check permission */ 1573 debug("client_request_x11: request from %s %d", originator, 1574 originator_port); 1575 free(originator); 1576 sock = x11_connect_display(ssh); 1577 if (sock < 0) 1578 return NULL; 1579 c = channel_new(ssh, "x11", 1580 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1581 CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); 1582 c->force_drain = 1; 1583 return c; 1584 } 1585 1586 static Channel * 1587 client_request_agent(struct ssh *ssh, const char *request_type, int rchan) 1588 { 1589 Channel *c = NULL; 1590 int r, sock; 1591 1592 if (!options.forward_agent) { 1593 error("Warning: ssh server tried agent forwarding."); 1594 error("Warning: this is probably a break-in attempt by a " 1595 "malicious server."); 1596 return NULL; 1597 } 1598 if ((r = ssh_get_authentication_socket(&sock)) != 0) { 1599 if (r != SSH_ERR_AGENT_NOT_PRESENT) 1600 debug("%s: ssh_get_authentication_socket: %s", 1601 __func__, ssh_err(r)); 1602 return NULL; 1603 } 1604 c = channel_new(ssh, "authentication agent connection", 1605 SSH_CHANNEL_OPEN, sock, sock, -1, 1606 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, 1607 "authentication agent connection", 1); 1608 c->force_drain = 1; 1609 return c; 1610 } 1611 1612 char * 1613 client_request_tun_fwd(struct ssh *ssh, int tun_mode, 1614 int local_tun, int remote_tun) 1615 { 1616 Channel *c; 1617 int fd; 1618 char *ifname = NULL; 1619 1620 if (tun_mode == SSH_TUNMODE_NO) 1621 return 0; 1622 1623 debug("Requesting tun unit %d in mode %d", local_tun, tun_mode); 1624 1625 /* Open local tunnel device */ 1626 if ((fd = tun_open(local_tun, tun_mode, &ifname)) == -1) { 1627 error("Tunnel device open failed."); 1628 return NULL; 1629 } 1630 debug("Tunnel forwarding using interface %s", ifname); 1631 1632 c = channel_new(ssh, "tun", SSH_CHANNEL_OPENING, fd, fd, -1, 1633 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1); 1634 c->datagram = 1; 1635 1636 packet_start(SSH2_MSG_CHANNEL_OPEN); 1637 packet_put_cstring("tun@openssh.com"); 1638 packet_put_int(c->self); 1639 packet_put_int(c->local_window_max); 1640 packet_put_int(c->local_maxpacket); 1641 packet_put_int(tun_mode); 1642 packet_put_int(remote_tun); 1643 packet_send(); 1644 1645 return ifname; 1646 } 1647 1648 /* XXXX move to generic input handler */ 1649 static int 1650 client_input_channel_open(int type, u_int32_t seq, struct ssh *ssh) 1651 { 1652 Channel *c = NULL; 1653 char *ctype; 1654 int rchan; 1655 u_int rmaxpack, rwindow, len; 1656 1657 ctype = packet_get_string(&len); 1658 rchan = packet_get_int(); 1659 rwindow = packet_get_int(); 1660 rmaxpack = packet_get_int(); 1661 1662 debug("client_input_channel_open: ctype %s rchan %d win %d max %d", 1663 ctype, rchan, rwindow, rmaxpack); 1664 1665 if (strcmp(ctype, "forwarded-tcpip") == 0) { 1666 c = client_request_forwarded_tcpip(ssh, ctype, rchan, rwindow, 1667 rmaxpack); 1668 } else if (strcmp(ctype, "forwarded-streamlocal@openssh.com") == 0) { 1669 c = client_request_forwarded_streamlocal(ssh, ctype, rchan); 1670 } else if (strcmp(ctype, "x11") == 0) { 1671 c = client_request_x11(ssh, ctype, rchan); 1672 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) { 1673 c = client_request_agent(ssh, ctype, rchan); 1674 } 1675 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) { 1676 debug3("proxied to downstream: %s", ctype); 1677 } else if (c != NULL) { 1678 debug("confirm %s", ctype); 1679 c->remote_id = rchan; 1680 c->have_remote_id = 1; 1681 c->remote_window = rwindow; 1682 c->remote_maxpacket = rmaxpack; 1683 if (c->type != SSH_CHANNEL_CONNECTING) { 1684 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); 1685 packet_put_int(c->remote_id); 1686 packet_put_int(c->self); 1687 packet_put_int(c->local_window); 1688 packet_put_int(c->local_maxpacket); 1689 packet_send(); 1690 } 1691 } else { 1692 debug("failure %s", ctype); 1693 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); 1694 packet_put_int(rchan); 1695 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED); 1696 packet_put_cstring("open failed"); 1697 packet_put_cstring(""); 1698 packet_send(); 1699 } 1700 free(ctype); 1701 return 0; 1702 } 1703 1704 static int 1705 client_input_channel_req(int type, u_int32_t seq, struct ssh *ssh) 1706 { 1707 Channel *c = NULL; 1708 int exitval, id, reply, success = 0; 1709 char *rtype; 1710 1711 id = packet_get_int(); 1712 c = channel_lookup(ssh, id); 1713 if (channel_proxy_upstream(c, type, seq, ssh)) 1714 return 0; 1715 rtype = packet_get_string(NULL); 1716 reply = packet_get_char(); 1717 1718 debug("client_input_channel_req: channel %d rtype %s reply %d", 1719 id, rtype, reply); 1720 1721 if (id == -1) { 1722 error("client_input_channel_req: request for channel -1"); 1723 } else if (c == NULL) { 1724 error("client_input_channel_req: channel %d: " 1725 "unknown channel", id); 1726 } else if (strcmp(rtype, "eow@openssh.com") == 0) { 1727 packet_check_eom(); 1728 chan_rcvd_eow(ssh, c); 1729 } else if (strcmp(rtype, "exit-status") == 0) { 1730 exitval = packet_get_int(); 1731 if (c->ctl_chan != -1) { 1732 mux_exit_message(ssh, c, exitval); 1733 success = 1; 1734 } else if (id == session_ident) { 1735 /* Record exit value of local session */ 1736 success = 1; 1737 exit_status = exitval; 1738 } else { 1739 /* Probably for a mux channel that has already closed */ 1740 debug("%s: no sink for exit-status on channel %d", 1741 __func__, id); 1742 } 1743 packet_check_eom(); 1744 } 1745 if (reply && c != NULL && !(c->flags & CHAN_CLOSE_SENT)) { 1746 if (!c->have_remote_id) 1747 fatal("%s: channel %d: no remote_id", 1748 __func__, c->self); 1749 packet_start(success ? 1750 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE); 1751 packet_put_int(c->remote_id); 1752 packet_send(); 1753 } 1754 free(rtype); 1755 return 0; 1756 } 1757 1758 struct hostkeys_update_ctx { 1759 /* The hostname and (optionally) IP address string for the server */ 1760 char *host_str, *ip_str; 1761 1762 /* 1763 * Keys received from the server and a flag for each indicating 1764 * whether they already exist in known_hosts. 1765 * keys_seen is filled in by hostkeys_find() and later (for new 1766 * keys) by client_global_hostkeys_private_confirm(). 1767 */ 1768 struct sshkey **keys; 1769 int *keys_seen; 1770 size_t nkeys, nnew; 1771 1772 /* 1773 * Keys that are in known_hosts, but were not present in the update 1774 * from the server (i.e. scheduled to be deleted). 1775 * Filled in by hostkeys_find(). 1776 */ 1777 struct sshkey **old_keys; 1778 size_t nold; 1779 }; 1780 1781 static void 1782 hostkeys_update_ctx_free(struct hostkeys_update_ctx *ctx) 1783 { 1784 size_t i; 1785 1786 if (ctx == NULL) 1787 return; 1788 for (i = 0; i < ctx->nkeys; i++) 1789 sshkey_free(ctx->keys[i]); 1790 free(ctx->keys); 1791 free(ctx->keys_seen); 1792 for (i = 0; i < ctx->nold; i++) 1793 sshkey_free(ctx->old_keys[i]); 1794 free(ctx->old_keys); 1795 free(ctx->host_str); 1796 free(ctx->ip_str); 1797 free(ctx); 1798 } 1799 1800 static int 1801 hostkeys_find(struct hostkey_foreach_line *l, void *_ctx) 1802 { 1803 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 1804 size_t i; 1805 struct sshkey **tmp; 1806 1807 if (l->status != HKF_STATUS_MATCHED || l->key == NULL) 1808 return 0; 1809 1810 /* Mark off keys we've already seen for this host */ 1811 for (i = 0; i < ctx->nkeys; i++) { 1812 if (sshkey_equal(l->key, ctx->keys[i])) { 1813 debug3("%s: found %s key at %s:%ld", __func__, 1814 sshkey_ssh_name(ctx->keys[i]), l->path, l->linenum); 1815 ctx->keys_seen[i] = 1; 1816 return 0; 1817 } 1818 } 1819 /* This line contained a key that not offered by the server */ 1820 debug3("%s: deprecated %s key at %s:%ld", __func__, 1821 sshkey_ssh_name(l->key), l->path, l->linenum); 1822 if ((tmp = recallocarray(ctx->old_keys, ctx->nold, ctx->nold + 1, 1823 sizeof(*ctx->old_keys))) == NULL) 1824 fatal("%s: recallocarray failed nold = %zu", 1825 __func__, ctx->nold); 1826 ctx->old_keys = tmp; 1827 ctx->old_keys[ctx->nold++] = l->key; 1828 l->key = NULL; 1829 1830 return 0; 1831 } 1832 1833 static void 1834 update_known_hosts(struct hostkeys_update_ctx *ctx) 1835 { 1836 int r, was_raw = 0; 1837 int loglevel = options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK ? 1838 SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_VERBOSE; 1839 char *fp, *response; 1840 size_t i; 1841 1842 for (i = 0; i < ctx->nkeys; i++) { 1843 if (ctx->keys_seen[i] != 2) 1844 continue; 1845 if ((fp = sshkey_fingerprint(ctx->keys[i], 1846 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 1847 fatal("%s: sshkey_fingerprint failed", __func__); 1848 do_log2(loglevel, "Learned new hostkey: %s %s", 1849 sshkey_type(ctx->keys[i]), fp); 1850 free(fp); 1851 } 1852 for (i = 0; i < ctx->nold; i++) { 1853 if ((fp = sshkey_fingerprint(ctx->old_keys[i], 1854 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 1855 fatal("%s: sshkey_fingerprint failed", __func__); 1856 do_log2(loglevel, "Deprecating obsolete hostkey: %s %s", 1857 sshkey_type(ctx->old_keys[i]), fp); 1858 free(fp); 1859 } 1860 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) { 1861 if (get_saved_tio() != NULL) { 1862 leave_raw_mode(1); 1863 was_raw = 1; 1864 } 1865 response = NULL; 1866 for (i = 0; !quit_pending && i < 3; i++) { 1867 free(response); 1868 response = read_passphrase("Accept updated hostkeys? " 1869 "(yes/no): ", RP_ECHO); 1870 if (strcasecmp(response, "yes") == 0) 1871 break; 1872 else if (quit_pending || response == NULL || 1873 strcasecmp(response, "no") == 0) { 1874 options.update_hostkeys = 0; 1875 break; 1876 } else { 1877 do_log2(loglevel, "Please enter " 1878 "\"yes\" or \"no\""); 1879 } 1880 } 1881 if (quit_pending || i >= 3 || response == NULL) 1882 options.update_hostkeys = 0; 1883 free(response); 1884 if (was_raw) 1885 enter_raw_mode(1); 1886 } 1887 1888 /* 1889 * Now that all the keys are verified, we can go ahead and replace 1890 * them in known_hosts (assuming SSH_UPDATE_HOSTKEYS_ASK didn't 1891 * cancel the operation). 1892 */ 1893 if (options.update_hostkeys != 0 && 1894 (r = hostfile_replace_entries(options.user_hostfiles[0], 1895 ctx->host_str, ctx->ip_str, ctx->keys, ctx->nkeys, 1896 options.hash_known_hosts, 0, 1897 options.fingerprint_hash)) != 0) 1898 error("%s: hostfile_replace_entries failed: %s", 1899 __func__, ssh_err(r)); 1900 } 1901 1902 static void 1903 client_global_hostkeys_private_confirm(struct ssh *ssh, int type, 1904 u_int32_t seq, void *_ctx) 1905 { 1906 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 1907 size_t i, ndone; 1908 struct sshbuf *signdata; 1909 int r, kexsigtype, use_kexsigtype; 1910 const u_char *sig; 1911 size_t siglen; 1912 1913 if (ctx->nnew == 0) 1914 fatal("%s: ctx->nnew == 0", __func__); /* sanity */ 1915 if (type != SSH2_MSG_REQUEST_SUCCESS) { 1916 error("Server failed to confirm ownership of " 1917 "private host keys"); 1918 hostkeys_update_ctx_free(ctx); 1919 return; 1920 } 1921 kexsigtype = sshkey_type_plain( 1922 sshkey_type_from_name(ssh->kex->hostkey_alg)); 1923 1924 if ((signdata = sshbuf_new()) == NULL) 1925 fatal("%s: sshbuf_new failed", __func__); 1926 /* Don't want to accidentally accept an unbound signature */ 1927 if (ssh->kex->session_id_len == 0) 1928 fatal("%s: ssh->kex->session_id_len == 0", __func__); 1929 /* 1930 * Expect a signature for each of the ctx->nnew private keys we 1931 * haven't seen before. They will be in the same order as the 1932 * ctx->keys where the corresponding ctx->keys_seen[i] == 0. 1933 */ 1934 for (ndone = i = 0; i < ctx->nkeys; i++) { 1935 if (ctx->keys_seen[i]) 1936 continue; 1937 /* Prepare data to be signed: session ID, unique string, key */ 1938 sshbuf_reset(signdata); 1939 if ( (r = sshbuf_put_cstring(signdata, 1940 "hostkeys-prove-00@openssh.com")) != 0 || 1941 (r = sshbuf_put_string(signdata, ssh->kex->session_id, 1942 ssh->kex->session_id_len)) != 0 || 1943 (r = sshkey_puts(ctx->keys[i], signdata)) != 0) 1944 fatal("%s: failed to prepare signature: %s", 1945 __func__, ssh_err(r)); 1946 /* Extract and verify signature */ 1947 if ((r = sshpkt_get_string_direct(ssh, &sig, &siglen)) != 0) { 1948 error("%s: couldn't parse message: %s", 1949 __func__, ssh_err(r)); 1950 goto out; 1951 } 1952 /* 1953 * For RSA keys, prefer to use the signature type negotiated 1954 * during KEX to the default (SHA1). 1955 */ 1956 use_kexsigtype = kexsigtype == KEY_RSA && 1957 sshkey_type_plain(ctx->keys[i]->type) == KEY_RSA; 1958 if ((r = sshkey_verify(ctx->keys[i], sig, siglen, 1959 sshbuf_ptr(signdata), sshbuf_len(signdata), 1960 use_kexsigtype ? ssh->kex->hostkey_alg : NULL, 0)) != 0) { 1961 error("%s: server gave bad signature for %s key %zu", 1962 __func__, sshkey_type(ctx->keys[i]), i); 1963 goto out; 1964 } 1965 /* Key is good. Mark it as 'seen' */ 1966 ctx->keys_seen[i] = 2; 1967 ndone++; 1968 } 1969 if (ndone != ctx->nnew) 1970 fatal("%s: ndone != ctx->nnew (%zu / %zu)", __func__, 1971 ndone, ctx->nnew); /* Shouldn't happen */ 1972 ssh_packet_check_eom(ssh); 1973 1974 /* Make the edits to known_hosts */ 1975 update_known_hosts(ctx); 1976 out: 1977 hostkeys_update_ctx_free(ctx); 1978 } 1979 1980 /* 1981 * Returns non-zero if the key is accepted by HostkeyAlgorithms. 1982 * Made slightly less trivial by the multiple RSA signature algorithm names. 1983 */ 1984 static int 1985 key_accepted_by_hostkeyalgs(const struct sshkey *key) 1986 { 1987 const char *ktype = sshkey_ssh_name(key); 1988 const char *hostkeyalgs = options.hostkeyalgorithms != NULL ? 1989 options.hostkeyalgorithms : KEX_DEFAULT_PK_ALG; 1990 1991 if (key == NULL || key->type == KEY_UNSPEC) 1992 return 0; 1993 if (key->type == KEY_RSA && 1994 (match_pattern_list("rsa-sha2-256", hostkeyalgs, 0) == 1 || 1995 match_pattern_list("rsa-sha2-512", hostkeyalgs, 0) == 1)) 1996 return 1; 1997 return match_pattern_list(ktype, hostkeyalgs, 0) == 1; 1998 } 1999 2000 /* 2001 * Handle hostkeys-00@openssh.com global request to inform the client of all 2002 * the server's hostkeys. The keys are checked against the user's 2003 * HostkeyAlgorithms preference before they are accepted. 2004 */ 2005 static int 2006 client_input_hostkeys(void) 2007 { 2008 struct ssh *ssh = active_state; /* XXX */ 2009 const u_char *blob = NULL; 2010 size_t i, len = 0; 2011 struct sshbuf *buf = NULL; 2012 struct sshkey *key = NULL, **tmp; 2013 int r; 2014 char *fp; 2015 static int hostkeys_seen = 0; /* XXX use struct ssh */ 2016 extern struct sockaddr_storage hostaddr; /* XXX from ssh.c */ 2017 struct hostkeys_update_ctx *ctx = NULL; 2018 2019 if (hostkeys_seen) 2020 fatal("%s: server already sent hostkeys", __func__); 2021 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK && 2022 options.batch_mode) 2023 return 1; /* won't ask in batchmode, so don't even try */ 2024 if (!options.update_hostkeys || options.num_user_hostfiles <= 0) 2025 return 1; 2026 2027 ctx = xcalloc(1, sizeof(*ctx)); 2028 while (ssh_packet_remaining(ssh) > 0) { 2029 sshkey_free(key); 2030 key = NULL; 2031 if ((r = sshpkt_get_string_direct(ssh, &blob, &len)) != 0) { 2032 error("%s: couldn't parse message: %s", 2033 __func__, ssh_err(r)); 2034 goto out; 2035 } 2036 if ((r = sshkey_from_blob(blob, len, &key)) != 0) { 2037 error("%s: parse key: %s", __func__, ssh_err(r)); 2038 goto out; 2039 } 2040 fp = sshkey_fingerprint(key, options.fingerprint_hash, 2041 SSH_FP_DEFAULT); 2042 debug3("%s: received %s key %s", __func__, 2043 sshkey_type(key), fp); 2044 free(fp); 2045 2046 if (!key_accepted_by_hostkeyalgs(key)) { 2047 debug3("%s: %s key not permitted by HostkeyAlgorithms", 2048 __func__, sshkey_ssh_name(key)); 2049 continue; 2050 } 2051 /* Skip certs */ 2052 if (sshkey_is_cert(key)) { 2053 debug3("%s: %s key is a certificate; skipping", 2054 __func__, sshkey_ssh_name(key)); 2055 continue; 2056 } 2057 /* Ensure keys are unique */ 2058 for (i = 0; i < ctx->nkeys; i++) { 2059 if (sshkey_equal(key, ctx->keys[i])) { 2060 error("%s: received duplicated %s host key", 2061 __func__, sshkey_ssh_name(key)); 2062 goto out; 2063 } 2064 } 2065 /* Key is good, record it */ 2066 if ((tmp = recallocarray(ctx->keys, ctx->nkeys, ctx->nkeys + 1, 2067 sizeof(*ctx->keys))) == NULL) 2068 fatal("%s: recallocarray failed nkeys = %zu", 2069 __func__, ctx->nkeys); 2070 ctx->keys = tmp; 2071 ctx->keys[ctx->nkeys++] = key; 2072 key = NULL; 2073 } 2074 2075 if (ctx->nkeys == 0) { 2076 debug("%s: server sent no hostkeys", __func__); 2077 goto out; 2078 } 2079 2080 if ((ctx->keys_seen = calloc(ctx->nkeys, 2081 sizeof(*ctx->keys_seen))) == NULL) 2082 fatal("%s: calloc failed", __func__); 2083 2084 get_hostfile_hostname_ipaddr(host, 2085 options.check_host_ip ? (struct sockaddr *)&hostaddr : NULL, 2086 options.port, &ctx->host_str, 2087 options.check_host_ip ? &ctx->ip_str : NULL); 2088 2089 /* Find which keys we already know about. */ 2090 if ((r = hostkeys_foreach(options.user_hostfiles[0], hostkeys_find, 2091 ctx, ctx->host_str, ctx->ip_str, 2092 HKF_WANT_PARSE_KEY|HKF_WANT_MATCH)) != 0) { 2093 error("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r)); 2094 goto out; 2095 } 2096 2097 /* Figure out if we have any new keys to add */ 2098 ctx->nnew = 0; 2099 for (i = 0; i < ctx->nkeys; i++) { 2100 if (!ctx->keys_seen[i]) 2101 ctx->nnew++; 2102 } 2103 2104 debug3("%s: %zu keys from server: %zu new, %zu retained. %zu to remove", 2105 __func__, ctx->nkeys, ctx->nnew, ctx->nkeys - ctx->nnew, ctx->nold); 2106 2107 if (ctx->nnew == 0 && ctx->nold != 0) { 2108 /* We have some keys to remove. Just do it. */ 2109 update_known_hosts(ctx); 2110 } else if (ctx->nnew != 0) { 2111 /* 2112 * We have received hitherto-unseen keys from the server. 2113 * Ask the server to confirm ownership of the private halves. 2114 */ 2115 debug3("%s: asking server to prove ownership for %zu keys", 2116 __func__, ctx->nnew); 2117 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 2118 (r = sshpkt_put_cstring(ssh, 2119 "hostkeys-prove-00@openssh.com")) != 0 || 2120 (r = sshpkt_put_u8(ssh, 1)) != 0) /* bool: want reply */ 2121 fatal("%s: cannot prepare packet: %s", 2122 __func__, ssh_err(r)); 2123 if ((buf = sshbuf_new()) == NULL) 2124 fatal("%s: sshbuf_new", __func__); 2125 for (i = 0; i < ctx->nkeys; i++) { 2126 if (ctx->keys_seen[i]) 2127 continue; 2128 sshbuf_reset(buf); 2129 if ((r = sshkey_putb(ctx->keys[i], buf)) != 0) 2130 fatal("%s: sshkey_putb: %s", 2131 __func__, ssh_err(r)); 2132 if ((r = sshpkt_put_stringb(ssh, buf)) != 0) 2133 fatal("%s: sshpkt_put_string: %s", 2134 __func__, ssh_err(r)); 2135 } 2136 if ((r = sshpkt_send(ssh)) != 0) 2137 fatal("%s: sshpkt_send: %s", __func__, ssh_err(r)); 2138 client_register_global_confirm( 2139 client_global_hostkeys_private_confirm, ctx); 2140 ctx = NULL; /* will be freed in callback */ 2141 } 2142 2143 /* Success */ 2144 out: 2145 hostkeys_update_ctx_free(ctx); 2146 sshkey_free(key); 2147 sshbuf_free(buf); 2148 /* 2149 * NB. Return success for all cases. The server doesn't need to know 2150 * what the client does with its hosts file. 2151 */ 2152 return 1; 2153 } 2154 2155 static int 2156 client_input_global_request(int type, u_int32_t seq, struct ssh *ssh) 2157 { 2158 char *rtype; 2159 int want_reply; 2160 int success = 0; 2161 2162 rtype = packet_get_cstring(NULL); 2163 want_reply = packet_get_char(); 2164 debug("client_input_global_request: rtype %s want_reply %d", 2165 rtype, want_reply); 2166 if (strcmp(rtype, "hostkeys-00@openssh.com") == 0) 2167 success = client_input_hostkeys(); 2168 if (want_reply) { 2169 packet_start(success ? 2170 SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE); 2171 packet_send(); 2172 packet_write_wait(); 2173 } 2174 free(rtype); 2175 return 0; 2176 } 2177 2178 void 2179 client_session2_setup(struct ssh *ssh, int id, int want_tty, int want_subsystem, 2180 const char *term, struct termios *tiop, int in_fd, struct sshbuf *cmd, 2181 char **env) 2182 { 2183 int i, j, matched, len; 2184 char *name, *val; 2185 Channel *c = NULL; 2186 2187 debug2("%s: id %d", __func__, id); 2188 2189 if ((c = channel_lookup(ssh, id)) == NULL) 2190 fatal("%s: channel %d: unknown channel", __func__, id); 2191 2192 packet_set_interactive(want_tty, 2193 options.ip_qos_interactive, options.ip_qos_bulk); 2194 2195 if (want_tty) { 2196 struct winsize ws; 2197 2198 /* Store window size in the packet. */ 2199 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0) 2200 memset(&ws, 0, sizeof(ws)); 2201 2202 channel_request_start(ssh, id, "pty-req", 1); 2203 client_expect_confirm(ssh, id, "PTY allocation", CONFIRM_TTY); 2204 packet_put_cstring(term != NULL ? term : ""); 2205 packet_put_int((u_int)ws.ws_col); 2206 packet_put_int((u_int)ws.ws_row); 2207 packet_put_int((u_int)ws.ws_xpixel); 2208 packet_put_int((u_int)ws.ws_ypixel); 2209 if (tiop == NULL) 2210 tiop = get_saved_tio(); 2211 ssh_tty_make_modes(ssh, -1, tiop); 2212 packet_send(); 2213 /* XXX wait for reply */ 2214 c->client_tty = 1; 2215 } 2216 2217 /* Transfer any environment variables from client to server */ 2218 if (options.num_send_env != 0 && env != NULL) { 2219 debug("Sending environment."); 2220 for (i = 0; env[i] != NULL; i++) { 2221 /* Split */ 2222 name = xstrdup(env[i]); 2223 if ((val = strchr(name, '=')) == NULL) { 2224 free(name); 2225 continue; 2226 } 2227 *val++ = '\0'; 2228 2229 matched = 0; 2230 for (j = 0; j < options.num_send_env; j++) { 2231 if (match_pattern(name, options.send_env[j])) { 2232 matched = 1; 2233 break; 2234 } 2235 } 2236 if (!matched) { 2237 debug3("Ignored env %s", name); 2238 free(name); 2239 continue; 2240 } 2241 2242 debug("Sending env %s = %s", name, val); 2243 channel_request_start(ssh, id, "env", 0); 2244 packet_put_cstring(name); 2245 packet_put_cstring(val); 2246 packet_send(); 2247 free(name); 2248 } 2249 } 2250 for (i = 0; i < options.num_setenv; i++) { 2251 /* Split */ 2252 name = xstrdup(options.setenv[i]); 2253 if ((val = strchr(name, '=')) == NULL) { 2254 free(name); 2255 continue; 2256 } 2257 *val++ = '\0'; 2258 2259 debug("Setting env %s = %s", name, val); 2260 channel_request_start(ssh, id, "env", 0); 2261 packet_put_cstring(name); 2262 packet_put_cstring(val); 2263 packet_send(); 2264 free(name); 2265 } 2266 2267 len = sshbuf_len(cmd); 2268 if (len > 0) { 2269 if (len > 900) 2270 len = 900; 2271 if (want_subsystem) { 2272 debug("Sending subsystem: %.*s", 2273 len, (const u_char*)sshbuf_ptr(cmd)); 2274 channel_request_start(ssh, id, "subsystem", 1); 2275 client_expect_confirm(ssh, id, "subsystem", 2276 CONFIRM_CLOSE); 2277 } else { 2278 debug("Sending command: %.*s", 2279 len, (const u_char*)sshbuf_ptr(cmd)); 2280 channel_request_start(ssh, id, "exec", 1); 2281 client_expect_confirm(ssh, id, "exec", CONFIRM_CLOSE); 2282 } 2283 packet_put_string(sshbuf_ptr(cmd), sshbuf_len(cmd)); 2284 packet_send(); 2285 } else { 2286 channel_request_start(ssh, id, "shell", 1); 2287 client_expect_confirm(ssh, id, "shell", CONFIRM_CLOSE); 2288 packet_send(); 2289 } 2290 } 2291 2292 static void 2293 client_init_dispatch(void) 2294 { 2295 dispatch_init(&dispatch_protocol_error); 2296 2297 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); 2298 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); 2299 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); 2300 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); 2301 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open); 2302 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 2303 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 2304 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req); 2305 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); 2306 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm); 2307 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm); 2308 dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request); 2309 2310 /* rekeying */ 2311 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); 2312 2313 /* global request reply messages */ 2314 dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply); 2315 dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply); 2316 } 2317 2318 void 2319 client_stop_mux(void) 2320 { 2321 if (options.control_path != NULL && muxserver_sock != -1) 2322 unlink(options.control_path); 2323 /* 2324 * If we are in persist mode, or don't have a shell, signal that we 2325 * should close when all active channels are closed. 2326 */ 2327 if (options.control_persist || no_shell_flag) { 2328 session_closed = 1; 2329 setproctitle("[stopped mux]"); 2330 } 2331 } 2332 2333 /* client specific fatal cleanup */ 2334 void 2335 cleanup_exit(int i) 2336 { 2337 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 2338 leave_non_blocking(); 2339 if (options.control_path != NULL && muxserver_sock != -1) 2340 unlink(options.control_path); 2341 ssh_kill_proxy_command(); 2342 _exit(i); 2343 } 2344