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 #include "includes.h" 63 64 #include <sys/types.h> 65 #include <sys/ioctl.h> 66 #ifdef HAVE_SYS_STAT_H 67 # include <sys/stat.h> 68 #endif 69 #ifdef HAVE_SYS_TIME_H 70 # include <sys/time.h> 71 #endif 72 #include <sys/socket.h> 73 74 #include <ctype.h> 75 #include <errno.h> 76 #ifdef HAVE_PATHS_H 77 #include <paths.h> 78 #endif 79 #include <signal.h> 80 #include <stdarg.h> 81 #include <stdio.h> 82 #include <stdlib.h> 83 #include <string.h> 84 #include <termios.h> 85 #include <pwd.h> 86 #include <unistd.h> 87 #include <limits.h> 88 89 #include "openbsd-compat/sys-queue.h" 90 #include "xmalloc.h" 91 #include "ssh.h" 92 #include "ssh2.h" 93 #include "packet.h" 94 #include "sshbuf.h" 95 #include "compat.h" 96 #include "channels.h" 97 #include "dispatch.h" 98 #include "sshkey.h" 99 #include "cipher.h" 100 #include "kex.h" 101 #include "myproposal.h" 102 #include "log.h" 103 #include "misc.h" 104 #include "readconf.h" 105 #include "clientloop.h" 106 #include "sshconnect.h" 107 #include "authfd.h" 108 #include "atomicio.h" 109 #include "sshpty.h" 110 #include "match.h" 111 #include "msg.h" 112 #include "ssherr.h" 113 #include "hostfile.h" 114 115 /* import options */ 116 extern Options options; 117 118 /* Flag indicating that stdin should be redirected from /dev/null. */ 119 extern int stdin_null_flag; 120 121 /* Flag indicating that no shell has been requested */ 122 extern int no_shell_flag; 123 124 /* Flag indicating that ssh should daemonise after authentication is complete */ 125 extern int fork_after_authentication_flag; 126 127 /* Control socket */ 128 extern int muxserver_sock; /* XXX use mux_client_cleanup() instead */ 129 130 /* 131 * Name of the host we are connecting to. This is the name given on the 132 * command line, or the HostName specified for the user-supplied name in a 133 * configuration file. 134 */ 135 extern char *host; 136 137 /* 138 * Flag to indicate that we have received a window change signal which has 139 * not yet been processed. This will cause a message indicating the new 140 * window size to be sent to the server a little later. This is volatile 141 * because this is updated in a signal handler. 142 */ 143 static volatile sig_atomic_t received_window_change_signal = 0; 144 static volatile sig_atomic_t received_signal = 0; 145 146 /* Flag indicating whether the user's terminal is in non-blocking mode. */ 147 static int in_non_blocking_mode = 0; 148 149 /* Time when backgrounded control master using ControlPersist should exit */ 150 static time_t control_persist_exit_time = 0; 151 152 /* Common data for the client loop code. */ 153 volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */ 154 static int last_was_cr; /* Last character was a newline. */ 155 static int exit_status; /* Used to store the command exit status. */ 156 static struct sshbuf *stderr_buffer; /* Used for final exit message. */ 157 static int connection_in; /* Connection to server (input). */ 158 static int connection_out; /* Connection to server (output). */ 159 static int need_rekeying; /* Set to non-zero if rekeying is requested. */ 160 static int session_closed; /* In SSH2: login session closed. */ 161 static u_int x11_refuse_time; /* If >0, refuse x11 opens after this time. */ 162 163 static void client_init_dispatch(void); 164 int session_ident = -1; 165 166 /* Track escape per proto2 channel */ 167 struct escape_filter_ctx { 168 int escape_pending; 169 int escape_char; 170 }; 171 172 /* Context for channel confirmation replies */ 173 struct channel_reply_ctx { 174 const char *request_type; 175 int id; 176 enum confirm_action action; 177 }; 178 179 /* Global request success/failure callbacks */ 180 /* XXX move to struct ssh? */ 181 struct global_confirm { 182 TAILQ_ENTRY(global_confirm) entry; 183 global_confirm_cb *cb; 184 void *ctx; 185 int ref_count; 186 }; 187 TAILQ_HEAD(global_confirms, global_confirm); 188 static struct global_confirms global_confirms = 189 TAILQ_HEAD_INITIALIZER(global_confirms); 190 191 void ssh_process_session2_setup(int, int, int, struct sshbuf *); 192 193 /* Restores stdin to blocking mode. */ 194 195 static void 196 leave_non_blocking(void) 197 { 198 if (in_non_blocking_mode) { 199 unset_nonblock(fileno(stdin)); 200 in_non_blocking_mode = 0; 201 } 202 } 203 204 /* 205 * Signal handler for the window change signal (SIGWINCH). This just sets a 206 * flag indicating that the window has changed. 207 */ 208 /*ARGSUSED */ 209 static void 210 window_change_handler(int sig) 211 { 212 received_window_change_signal = 1; 213 } 214 215 /* 216 * Signal handler for signals that cause the program to terminate. These 217 * signals must be trapped to restore terminal modes. 218 */ 219 /*ARGSUSED */ 220 static void 221 signal_handler(int sig) 222 { 223 received_signal = sig; 224 quit_pending = 1; 225 } 226 227 /* 228 * Sets control_persist_exit_time to the absolute time when the 229 * backgrounded control master should exit due to expiry of the 230 * ControlPersist timeout. Sets it to 0 if we are not a backgrounded 231 * control master process, or if there is no ControlPersist timeout. 232 */ 233 static void 234 set_control_persist_exit_time(struct ssh *ssh) 235 { 236 if (muxserver_sock == -1 || !options.control_persist 237 || options.control_persist_timeout == 0) { 238 /* not using a ControlPersist timeout */ 239 control_persist_exit_time = 0; 240 } else if (channel_still_open(ssh)) { 241 /* some client connections are still open */ 242 if (control_persist_exit_time > 0) 243 debug2("%s: cancel scheduled exit", __func__); 244 control_persist_exit_time = 0; 245 } else if (control_persist_exit_time <= 0) { 246 /* a client connection has recently closed */ 247 control_persist_exit_time = monotime() + 248 (time_t)options.control_persist_timeout; 249 debug2("%s: schedule exit in %d seconds", __func__, 250 options.control_persist_timeout); 251 } 252 /* else we are already counting down to the timeout */ 253 } 254 255 #define SSH_X11_VALID_DISPLAY_CHARS ":/.-_" 256 static int 257 client_x11_display_valid(const char *display) 258 { 259 size_t i, dlen; 260 261 if (display == NULL) 262 return 0; 263 264 dlen = strlen(display); 265 for (i = 0; i < dlen; i++) { 266 if (!isalnum((u_char)display[i]) && 267 strchr(SSH_X11_VALID_DISPLAY_CHARS, display[i]) == NULL) { 268 debug("Invalid character '%c' in DISPLAY", display[i]); 269 return 0; 270 } 271 } 272 return 1; 273 } 274 275 #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1" 276 #define X11_TIMEOUT_SLACK 60 277 int 278 client_x11_get_proto(struct ssh *ssh, const char *display, 279 const char *xauth_path, u_int trusted, u_int timeout, 280 char **_proto, char **_data) 281 { 282 char *cmd, line[512], xdisplay[512]; 283 char xauthfile[PATH_MAX], xauthdir[PATH_MAX]; 284 static char proto[512], data[512]; 285 FILE *f; 286 int got_data = 0, generated = 0, do_unlink = 0, r; 287 struct stat st; 288 u_int now, x11_timeout_real; 289 290 *_proto = proto; 291 *_data = data; 292 proto[0] = data[0] = xauthfile[0] = xauthdir[0] = '\0'; 293 294 if (!client_x11_display_valid(display)) { 295 if (display != NULL) 296 logit("DISPLAY \"%s\" invalid; disabling X11 forwarding", 297 display); 298 return -1; 299 } 300 if (xauth_path != NULL && stat(xauth_path, &st) == -1) { 301 debug("No xauth program."); 302 xauth_path = NULL; 303 } 304 305 if (xauth_path != NULL) { 306 /* 307 * Handle FamilyLocal case where $DISPLAY does 308 * not match an authorization entry. For this we 309 * just try "xauth list unix:displaynum.screennum". 310 * XXX: "localhost" match to determine FamilyLocal 311 * is not perfect. 312 */ 313 if (strncmp(display, "localhost:", 10) == 0) { 314 if ((r = snprintf(xdisplay, sizeof(xdisplay), "unix:%s", 315 display + 10)) < 0 || 316 (size_t)r >= sizeof(xdisplay)) { 317 error("%s: display name too long", __func__); 318 return -1; 319 } 320 display = xdisplay; 321 } 322 if (trusted == 0) { 323 /* 324 * Generate an untrusted X11 auth cookie. 325 * 326 * The authentication cookie should briefly outlive 327 * ssh's willingness to forward X11 connections to 328 * avoid nasty fail-open behaviour in the X server. 329 */ 330 mktemp_proto(xauthdir, sizeof(xauthdir)); 331 if (mkdtemp(xauthdir) == NULL) { 332 error("%s: mkdtemp: %s", 333 __func__, strerror(errno)); 334 return -1; 335 } 336 do_unlink = 1; 337 if ((r = snprintf(xauthfile, sizeof(xauthfile), 338 "%s/xauthfile", xauthdir)) < 0 || 339 (size_t)r >= sizeof(xauthfile)) { 340 error("%s: xauthfile path too long", __func__); 341 unlink(xauthfile); 342 rmdir(xauthdir); 343 return -1; 344 } 345 346 if (timeout == 0) { 347 /* auth doesn't time out */ 348 xasprintf(&cmd, "%s -f %s generate %s %s " 349 "untrusted 2>%s", 350 xauth_path, xauthfile, display, 351 SSH_X11_PROTO, _PATH_DEVNULL); 352 } else { 353 /* Add some slack to requested expiry */ 354 if (timeout < UINT_MAX - X11_TIMEOUT_SLACK) 355 x11_timeout_real = timeout + 356 X11_TIMEOUT_SLACK; 357 else { 358 /* Don't overflow on long timeouts */ 359 x11_timeout_real = UINT_MAX; 360 } 361 xasprintf(&cmd, "%s -f %s generate %s %s " 362 "untrusted timeout %u 2>%s", 363 xauth_path, xauthfile, display, 364 SSH_X11_PROTO, x11_timeout_real, 365 _PATH_DEVNULL); 366 } 367 debug2("%s: %s", __func__, cmd); 368 369 if (timeout != 0 && x11_refuse_time == 0) { 370 now = monotime() + 1; 371 if (UINT_MAX - timeout < now) 372 x11_refuse_time = UINT_MAX; 373 else 374 x11_refuse_time = now + timeout; 375 channel_set_x11_refuse_time(ssh, 376 x11_refuse_time); 377 } 378 if (system(cmd) == 0) 379 generated = 1; 380 free(cmd); 381 } 382 383 /* 384 * When in untrusted mode, we read the cookie only if it was 385 * successfully generated as an untrusted one in the step 386 * above. 387 */ 388 if (trusted || generated) { 389 xasprintf(&cmd, 390 "%s %s%s list %s 2>" _PATH_DEVNULL, 391 xauth_path, 392 generated ? "-f " : "" , 393 generated ? xauthfile : "", 394 display); 395 debug2("x11_get_proto: %s", cmd); 396 f = popen(cmd, "r"); 397 if (f && fgets(line, sizeof(line), f) && 398 sscanf(line, "%*s %511s %511s", proto, data) == 2) 399 got_data = 1; 400 if (f) 401 pclose(f); 402 free(cmd); 403 } 404 } 405 406 if (do_unlink) { 407 unlink(xauthfile); 408 rmdir(xauthdir); 409 } 410 411 /* Don't fall back to fake X11 data for untrusted forwarding */ 412 if (!trusted && !got_data) { 413 error("Warning: untrusted X11 forwarding setup failed: " 414 "xauth key data not generated"); 415 return -1; 416 } 417 418 /* 419 * If we didn't get authentication data, just make up some 420 * data. The forwarding code will check the validity of the 421 * response anyway, and substitute this data. The X11 422 * server, however, will ignore this fake data and use 423 * whatever authentication mechanisms it was using otherwise 424 * for the local connection. 425 */ 426 if (!got_data) { 427 u_int8_t rnd[16]; 428 u_int i; 429 430 logit("Warning: No xauth data; " 431 "using fake authentication data for X11 forwarding."); 432 strlcpy(proto, SSH_X11_PROTO, sizeof proto); 433 arc4random_buf(rnd, sizeof(rnd)); 434 for (i = 0; i < sizeof(rnd); i++) { 435 snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", 436 rnd[i]); 437 } 438 } 439 440 return 0; 441 } 442 443 /* 444 * Checks if the client window has changed, and sends a packet about it to 445 * the server if so. The actual change is detected elsewhere (by a software 446 * interrupt on Unix); this just checks the flag and sends a message if 447 * appropriate. 448 */ 449 450 static void 451 client_check_window_change(struct ssh *ssh) 452 { 453 if (!received_window_change_signal) 454 return; 455 /** XXX race */ 456 received_window_change_signal = 0; 457 458 debug2("%s: changed", __func__); 459 460 channel_send_window_changes(ssh); 461 } 462 463 static int 464 client_global_request_reply(int type, u_int32_t seq, struct ssh *ssh) 465 { 466 struct global_confirm *gc; 467 468 if ((gc = TAILQ_FIRST(&global_confirms)) == NULL) 469 return 0; 470 if (gc->cb != NULL) 471 gc->cb(ssh, type, seq, gc->ctx); 472 if (--gc->ref_count <= 0) { 473 TAILQ_REMOVE(&global_confirms, gc, entry); 474 explicit_bzero(gc, sizeof(*gc)); 475 free(gc); 476 } 477 478 packet_set_alive_timeouts(0); 479 return 0; 480 } 481 482 static void 483 server_alive_check(void) 484 { 485 if (packet_inc_alive_timeouts() > options.server_alive_count_max) { 486 logit("Timeout, server %s not responding.", host); 487 cleanup_exit(255); 488 } 489 packet_start(SSH2_MSG_GLOBAL_REQUEST); 490 packet_put_cstring("keepalive@openssh.com"); 491 packet_put_char(1); /* boolean: want reply */ 492 packet_send(); 493 /* Insert an empty placeholder to maintain ordering */ 494 client_register_global_confirm(NULL, NULL); 495 } 496 497 /* 498 * Waits until the client can do something (some data becomes available on 499 * one of the file descriptors). 500 */ 501 static void 502 client_wait_until_can_do_something(struct ssh *ssh, 503 fd_set **readsetp, fd_set **writesetp, 504 int *maxfdp, u_int *nallocp, int rekeying) 505 { 506 struct timeval tv, *tvp; 507 int timeout_secs; 508 time_t minwait_secs = 0, server_alive_time = 0, now = monotime(); 509 int r, ret; 510 511 /* Add any selections by the channel mechanism. */ 512 channel_prepare_select(active_state, readsetp, writesetp, maxfdp, 513 nallocp, &minwait_secs); 514 515 /* channel_prepare_select could have closed the last channel */ 516 if (session_closed && !channel_still_open(ssh) && 517 !packet_have_data_to_write()) { 518 /* clear mask since we did not call select() */ 519 memset(*readsetp, 0, *nallocp); 520 memset(*writesetp, 0, *nallocp); 521 return; 522 } 523 524 FD_SET(connection_in, *readsetp); 525 526 /* Select server connection if have data to write to the server. */ 527 if (packet_have_data_to_write()) 528 FD_SET(connection_out, *writesetp); 529 530 /* 531 * Wait for something to happen. This will suspend the process until 532 * some selected descriptor can be read, written, or has some other 533 * event pending, or a timeout expires. 534 */ 535 536 timeout_secs = INT_MAX; /* we use INT_MAX to mean no timeout */ 537 if (options.server_alive_interval > 0) { 538 timeout_secs = options.server_alive_interval; 539 server_alive_time = now + options.server_alive_interval; 540 } 541 if (options.rekey_interval > 0 && !rekeying) 542 timeout_secs = MINIMUM(timeout_secs, packet_get_rekey_timeout()); 543 set_control_persist_exit_time(ssh); 544 if (control_persist_exit_time > 0) { 545 timeout_secs = MINIMUM(timeout_secs, 546 control_persist_exit_time - now); 547 if (timeout_secs < 0) 548 timeout_secs = 0; 549 } 550 if (minwait_secs != 0) 551 timeout_secs = MINIMUM(timeout_secs, (int)minwait_secs); 552 if (timeout_secs == INT_MAX) 553 tvp = NULL; 554 else { 555 tv.tv_sec = timeout_secs; 556 tv.tv_usec = 0; 557 tvp = &tv; 558 } 559 560 ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp); 561 if (ret < 0) { 562 /* 563 * We have to clear the select masks, because we return. 564 * We have to return, because the mainloop checks for the flags 565 * set by the signal handlers. 566 */ 567 memset(*readsetp, 0, *nallocp); 568 memset(*writesetp, 0, *nallocp); 569 570 if (errno == EINTR) 571 return; 572 /* Note: we might still have data in the buffers. */ 573 if ((r = sshbuf_putf(stderr_buffer, 574 "select: %s\r\n", strerror(errno))) != 0) 575 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 576 quit_pending = 1; 577 } else if (ret == 0) { 578 /* 579 * Timeout. Could have been either keepalive or rekeying. 580 * Keepalive we check here, rekeying is checked in clientloop. 581 */ 582 if (server_alive_time != 0 && server_alive_time <= monotime()) 583 server_alive_check(); 584 } 585 586 } 587 588 static void 589 client_suspend_self(struct sshbuf *bin, struct sshbuf *bout, struct sshbuf *berr) 590 { 591 /* Flush stdout and stderr buffers. */ 592 if (sshbuf_len(bout) > 0) 593 atomicio(vwrite, fileno(stdout), sshbuf_mutable_ptr(bout), 594 sshbuf_len(bout)); 595 if (sshbuf_len(berr) > 0) 596 atomicio(vwrite, fileno(stderr), sshbuf_mutable_ptr(berr), 597 sshbuf_len(berr)); 598 599 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 600 601 sshbuf_reset(bin); 602 sshbuf_reset(bout); 603 sshbuf_reset(berr); 604 605 /* Send the suspend signal to the program itself. */ 606 kill(getpid(), SIGTSTP); 607 608 /* Reset window sizes in case they have changed */ 609 received_window_change_signal = 1; 610 611 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 612 } 613 614 static void 615 client_process_net_input(fd_set *readset) 616 { 617 char buf[SSH_IOBUFSZ]; 618 int r, len; 619 620 /* 621 * Read input from the server, and add any such data to the buffer of 622 * the packet subsystem. 623 */ 624 if (FD_ISSET(connection_in, readset)) { 625 /* Read as much as possible. */ 626 len = read(connection_in, buf, sizeof(buf)); 627 if (len == 0) { 628 /* 629 * Received EOF. The remote host has closed the 630 * connection. 631 */ 632 if ((r = sshbuf_putf(stderr_buffer, 633 "Connection to %.300s closed by remote host.\r\n", 634 host)) != 0) 635 fatal("%s: buffer error: %s", 636 __func__, ssh_err(r)); 637 quit_pending = 1; 638 return; 639 } 640 /* 641 * There is a kernel bug on Solaris that causes select to 642 * sometimes wake up even though there is no data available. 643 */ 644 if (len < 0 && 645 (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK)) 646 len = 0; 647 648 if (len < 0) { 649 /* 650 * An error has encountered. Perhaps there is a 651 * network problem. 652 */ 653 if ((r = sshbuf_putf(stderr_buffer, 654 "Read from remote host %.300s: %.100s\r\n", 655 host, strerror(errno))) != 0) 656 fatal("%s: buffer error: %s", 657 __func__, ssh_err(r)); 658 quit_pending = 1; 659 return; 660 } 661 packet_process_incoming(buf, len); 662 } 663 } 664 665 static void 666 client_status_confirm(struct ssh *ssh, int type, Channel *c, void *ctx) 667 { 668 struct channel_reply_ctx *cr = (struct channel_reply_ctx *)ctx; 669 char errmsg[256]; 670 int r, tochan; 671 672 /* 673 * If a TTY was explicitly requested, then a failure to allocate 674 * one is fatal. 675 */ 676 if (cr->action == CONFIRM_TTY && 677 (options.request_tty == REQUEST_TTY_FORCE || 678 options.request_tty == REQUEST_TTY_YES)) 679 cr->action = CONFIRM_CLOSE; 680 681 /* XXX suppress on mux _client_ quietmode */ 682 tochan = options.log_level >= SYSLOG_LEVEL_ERROR && 683 c->ctl_chan != -1 && c->extended_usage == CHAN_EXTENDED_WRITE; 684 685 if (type == SSH2_MSG_CHANNEL_SUCCESS) { 686 debug2("%s request accepted on channel %d", 687 cr->request_type, c->self); 688 } else if (type == SSH2_MSG_CHANNEL_FAILURE) { 689 if (tochan) { 690 snprintf(errmsg, sizeof(errmsg), 691 "%s request failed\r\n", cr->request_type); 692 } else { 693 snprintf(errmsg, sizeof(errmsg), 694 "%s request failed on channel %d", 695 cr->request_type, c->self); 696 } 697 /* If error occurred on primary session channel, then exit */ 698 if (cr->action == CONFIRM_CLOSE && c->self == session_ident) 699 fatal("%s", errmsg); 700 /* 701 * If error occurred on mux client, append to 702 * their stderr. 703 */ 704 if (tochan) { 705 if ((r = sshbuf_put(c->extended, errmsg, 706 strlen(errmsg))) != 0) 707 fatal("%s: buffer error %s", __func__, 708 ssh_err(r)); 709 } else 710 error("%s", errmsg); 711 if (cr->action == CONFIRM_TTY) { 712 /* 713 * If a TTY allocation error occurred, then arrange 714 * for the correct TTY to leave raw mode. 715 */ 716 if (c->self == session_ident) 717 leave_raw_mode(0); 718 else 719 mux_tty_alloc_failed(ssh, c); 720 } else if (cr->action == CONFIRM_CLOSE) { 721 chan_read_failed(ssh, c); 722 chan_write_failed(ssh, c); 723 } 724 } 725 free(cr); 726 } 727 728 static void 729 client_abandon_status_confirm(struct ssh *ssh, Channel *c, void *ctx) 730 { 731 free(ctx); 732 } 733 734 void 735 client_expect_confirm(struct ssh *ssh, int id, const char *request, 736 enum confirm_action action) 737 { 738 struct channel_reply_ctx *cr = xcalloc(1, sizeof(*cr)); 739 740 cr->request_type = request; 741 cr->action = action; 742 743 channel_register_status_confirm(ssh, id, client_status_confirm, 744 client_abandon_status_confirm, cr); 745 } 746 747 void 748 client_register_global_confirm(global_confirm_cb *cb, void *ctx) 749 { 750 struct global_confirm *gc, *last_gc; 751 752 /* Coalesce identical callbacks */ 753 last_gc = TAILQ_LAST(&global_confirms, global_confirms); 754 if (last_gc && last_gc->cb == cb && last_gc->ctx == ctx) { 755 if (++last_gc->ref_count >= INT_MAX) 756 fatal("%s: last_gc->ref_count = %d", 757 __func__, last_gc->ref_count); 758 return; 759 } 760 761 gc = xcalloc(1, sizeof(*gc)); 762 gc->cb = cb; 763 gc->ctx = ctx; 764 gc->ref_count = 1; 765 TAILQ_INSERT_TAIL(&global_confirms, gc, entry); 766 } 767 768 static void 769 process_cmdline(struct ssh *ssh) 770 { 771 void (*handler)(int); 772 char *s, *cmd; 773 int ok, delete = 0, local = 0, remote = 0, dynamic = 0; 774 struct Forward fwd; 775 776 memset(&fwd, 0, sizeof(fwd)); 777 778 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 779 handler = signal(SIGINT, SIG_IGN); 780 cmd = s = read_passphrase("\r\nssh> ", RP_ECHO); 781 if (s == NULL) 782 goto out; 783 while (isspace((u_char)*s)) 784 s++; 785 if (*s == '-') 786 s++; /* Skip cmdline '-', if any */ 787 if (*s == '\0') 788 goto out; 789 790 if (*s == 'h' || *s == 'H' || *s == '?') { 791 logit("Commands:"); 792 logit(" -L[bind_address:]port:host:hostport " 793 "Request local forward"); 794 logit(" -R[bind_address:]port:host:hostport " 795 "Request remote forward"); 796 logit(" -D[bind_address:]port " 797 "Request dynamic forward"); 798 logit(" -KL[bind_address:]port " 799 "Cancel local forward"); 800 logit(" -KR[bind_address:]port " 801 "Cancel remote forward"); 802 logit(" -KD[bind_address:]port " 803 "Cancel dynamic forward"); 804 if (!options.permit_local_command) 805 goto out; 806 logit(" !args " 807 "Execute local command"); 808 goto out; 809 } 810 811 if (*s == '!' && options.permit_local_command) { 812 s++; 813 ssh_local_cmd(s); 814 goto out; 815 } 816 817 if (*s == 'K') { 818 delete = 1; 819 s++; 820 } 821 if (*s == 'L') 822 local = 1; 823 else if (*s == 'R') 824 remote = 1; 825 else if (*s == 'D') 826 dynamic = 1; 827 else { 828 logit("Invalid command."); 829 goto out; 830 } 831 832 while (isspace((u_char)*++s)) 833 ; 834 835 /* XXX update list of forwards in options */ 836 if (delete) { 837 /* We pass 1 for dynamicfwd to restrict to 1 or 2 fields. */ 838 if (!parse_forward(&fwd, s, 1, 0)) { 839 logit("Bad forwarding close specification."); 840 goto out; 841 } 842 if (remote) 843 ok = channel_request_rforward_cancel(ssh, &fwd) == 0; 844 else if (dynamic) 845 ok = channel_cancel_lport_listener(ssh, &fwd, 846 0, &options.fwd_opts) > 0; 847 else 848 ok = channel_cancel_lport_listener(ssh, &fwd, 849 CHANNEL_CANCEL_PORT_STATIC, 850 &options.fwd_opts) > 0; 851 if (!ok) { 852 logit("Unknown port forwarding."); 853 goto out; 854 } 855 logit("Canceled forwarding."); 856 } else { 857 if (!parse_forward(&fwd, s, dynamic, remote)) { 858 logit("Bad forwarding specification."); 859 goto out; 860 } 861 if (local || dynamic) { 862 if (!channel_setup_local_fwd_listener(ssh, &fwd, 863 &options.fwd_opts)) { 864 logit("Port forwarding failed."); 865 goto out; 866 } 867 } else { 868 if (channel_request_remote_forwarding(ssh, &fwd) < 0) { 869 logit("Port forwarding failed."); 870 goto out; 871 } 872 } 873 logit("Forwarding port."); 874 } 875 876 out: 877 signal(SIGINT, handler); 878 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 879 free(cmd); 880 free(fwd.listen_host); 881 free(fwd.listen_path); 882 free(fwd.connect_host); 883 free(fwd.connect_path); 884 } 885 886 /* reasons to suppress output of an escape command in help output */ 887 #define SUPPRESS_NEVER 0 /* never suppress, always show */ 888 #define SUPPRESS_MUXCLIENT 1 /* don't show in mux client sessions */ 889 #define SUPPRESS_MUXMASTER 2 /* don't show in mux master sessions */ 890 #define SUPPRESS_SYSLOG 4 /* don't show when logging to syslog */ 891 struct escape_help_text { 892 const char *cmd; 893 const char *text; 894 unsigned int flags; 895 }; 896 static struct escape_help_text esc_txt[] = { 897 {".", "terminate session", SUPPRESS_MUXMASTER}, 898 {".", "terminate connection (and any multiplexed sessions)", 899 SUPPRESS_MUXCLIENT}, 900 {"B", "send a BREAK to the remote system", SUPPRESS_NEVER}, 901 {"C", "open a command line", SUPPRESS_MUXCLIENT}, 902 {"R", "request rekey", SUPPRESS_NEVER}, 903 {"V/v", "decrease/increase verbosity (LogLevel)", SUPPRESS_MUXCLIENT}, 904 {"^Z", "suspend ssh", SUPPRESS_MUXCLIENT}, 905 {"#", "list forwarded connections", SUPPRESS_NEVER}, 906 {"&", "background ssh (when waiting for connections to terminate)", 907 SUPPRESS_MUXCLIENT}, 908 {"?", "this message", SUPPRESS_NEVER}, 909 }; 910 911 static void 912 print_escape_help(struct sshbuf *b, int escape_char, int mux_client, 913 int using_stderr) 914 { 915 unsigned int i, suppress_flags; 916 int r; 917 918 if ((r = sshbuf_putf(b, 919 "%c?\r\nSupported escape sequences:\r\n", escape_char)) != 0) 920 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 921 922 suppress_flags = 923 (mux_client ? SUPPRESS_MUXCLIENT : 0) | 924 (mux_client ? 0 : SUPPRESS_MUXMASTER) | 925 (using_stderr ? 0 : SUPPRESS_SYSLOG); 926 927 for (i = 0; i < sizeof(esc_txt)/sizeof(esc_txt[0]); i++) { 928 if (esc_txt[i].flags & suppress_flags) 929 continue; 930 if ((r = sshbuf_putf(b, " %c%-3s - %s\r\n", 931 escape_char, esc_txt[i].cmd, esc_txt[i].text)) != 0) 932 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 933 } 934 935 if ((r = sshbuf_putf(b, 936 " %c%c - send the escape character by typing it twice\r\n" 937 "(Note that escapes are only recognized immediately after " 938 "newline.)\r\n", escape_char, escape_char)) != 0) 939 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 940 } 941 942 /* 943 * Process the characters one by one. 944 */ 945 static int 946 process_escapes(struct ssh *ssh, Channel *c, 947 struct sshbuf *bin, struct sshbuf *bout, struct sshbuf *berr, 948 char *buf, int len) 949 { 950 pid_t pid; 951 int r, bytes = 0; 952 u_int i; 953 u_char ch; 954 char *s; 955 struct escape_filter_ctx *efc = c->filter_ctx == NULL ? 956 NULL : (struct escape_filter_ctx *)c->filter_ctx; 957 958 if (c->filter_ctx == NULL) 959 return 0; 960 961 if (len <= 0) 962 return (0); 963 964 for (i = 0; i < (u_int)len; i++) { 965 /* Get one character at a time. */ 966 ch = buf[i]; 967 968 if (efc->escape_pending) { 969 /* We have previously seen an escape character. */ 970 /* Clear the flag now. */ 971 efc->escape_pending = 0; 972 973 /* Process the escaped character. */ 974 switch (ch) { 975 case '.': 976 /* Terminate the connection. */ 977 if ((r = sshbuf_putf(berr, "%c.\r\n", 978 efc->escape_char)) != 0) 979 fatal("%s: buffer error: %s", 980 __func__, ssh_err(r)); 981 if (c && c->ctl_chan != -1) { 982 chan_read_failed(ssh, c); 983 chan_write_failed(ssh, c); 984 if (c->detach_user) { 985 c->detach_user(ssh, 986 c->self, NULL); 987 } 988 c->type = SSH_CHANNEL_ABANDONED; 989 sshbuf_reset(c->input); 990 chan_ibuf_empty(ssh, c); 991 return 0; 992 } else 993 quit_pending = 1; 994 return -1; 995 996 case 'Z' - 64: 997 /* XXX support this for mux clients */ 998 if (c && c->ctl_chan != -1) { 999 char b[16]; 1000 noescape: 1001 if (ch == 'Z' - 64) 1002 snprintf(b, sizeof b, "^Z"); 1003 else 1004 snprintf(b, sizeof b, "%c", ch); 1005 if ((r = sshbuf_putf(berr, 1006 "%c%s escape not available to " 1007 "multiplexed sessions\r\n", 1008 efc->escape_char, b)) != 0) 1009 fatal("%s: buffer error: %s", 1010 __func__, ssh_err(r)); 1011 continue; 1012 } 1013 /* Suspend the program. Inform the user */ 1014 if ((r = sshbuf_putf(berr, 1015 "%c^Z [suspend ssh]\r\n", 1016 efc->escape_char)) != 0) 1017 fatal("%s: buffer error: %s", 1018 __func__, ssh_err(r)); 1019 1020 /* Restore terminal modes and suspend. */ 1021 client_suspend_self(bin, bout, berr); 1022 1023 /* We have been continued. */ 1024 continue; 1025 1026 case 'B': 1027 if ((r = sshbuf_putf(berr, 1028 "%cB\r\n", efc->escape_char)) != 0) 1029 fatal("%s: buffer error: %s", 1030 __func__, ssh_err(r)); 1031 channel_request_start(ssh, c->self, "break", 0); 1032 if ((r = sshpkt_put_u32(ssh, 1000)) != 0 || 1033 (r = sshpkt_send(ssh)) != 0) 1034 fatal("%s: %s", __func__, 1035 ssh_err(r)); 1036 continue; 1037 1038 case 'R': 1039 if (datafellows & SSH_BUG_NOREKEY) 1040 logit("Server does not " 1041 "support re-keying"); 1042 else 1043 need_rekeying = 1; 1044 continue; 1045 1046 case 'V': 1047 /* FALLTHROUGH */ 1048 case 'v': 1049 if (c && c->ctl_chan != -1) 1050 goto noescape; 1051 if (!log_is_on_stderr()) { 1052 if ((r = sshbuf_putf(berr, 1053 "%c%c [Logging to syslog]\r\n", 1054 efc->escape_char, ch)) != 0) 1055 fatal("%s: buffer error: %s", 1056 __func__, ssh_err(r)); 1057 continue; 1058 } 1059 if (ch == 'V' && options.log_level > 1060 SYSLOG_LEVEL_QUIET) 1061 log_change_level(--options.log_level); 1062 if (ch == 'v' && options.log_level < 1063 SYSLOG_LEVEL_DEBUG3) 1064 log_change_level(++options.log_level); 1065 if ((r = sshbuf_putf(berr, 1066 "%c%c [LogLevel %s]\r\n", 1067 efc->escape_char, ch, 1068 log_level_name(options.log_level))) != 0) 1069 fatal("%s: buffer error: %s", 1070 __func__, ssh_err(r)); 1071 continue; 1072 1073 case '&': 1074 if (c && c->ctl_chan != -1) 1075 goto noescape; 1076 /* 1077 * Detach the program (continue to serve 1078 * connections, but put in background and no 1079 * more new connections). 1080 */ 1081 /* Restore tty modes. */ 1082 leave_raw_mode( 1083 options.request_tty == REQUEST_TTY_FORCE); 1084 1085 /* Stop listening for new connections. */ 1086 channel_stop_listening(ssh); 1087 1088 if ((r = sshbuf_putf(berr, 1089 "%c& [backgrounded]\n", efc->escape_char)) 1090 != 0) 1091 fatal("%s: buffer error: %s", 1092 __func__, ssh_err(r)); 1093 1094 /* Fork into background. */ 1095 pid = fork(); 1096 if (pid < 0) { 1097 error("fork: %.100s", strerror(errno)); 1098 continue; 1099 } 1100 if (pid != 0) { /* This is the parent. */ 1101 /* The parent just exits. */ 1102 exit(0); 1103 } 1104 /* The child continues serving connections. */ 1105 /* fake EOF on stdin */ 1106 if ((r = sshbuf_put_u8(bin, 4)) != 0) 1107 fatal("%s: buffer error: %s", 1108 __func__, ssh_err(r)); 1109 return -1; 1110 case '?': 1111 print_escape_help(berr, efc->escape_char, 1112 (c && c->ctl_chan != -1), 1113 log_is_on_stderr()); 1114 continue; 1115 1116 case '#': 1117 if ((r = sshbuf_putf(berr, "%c#\r\n", 1118 efc->escape_char)) != 0) 1119 fatal("%s: buffer error: %s", 1120 __func__, ssh_err(r)); 1121 s = channel_open_message(ssh); 1122 if ((r = sshbuf_put(berr, s, strlen(s))) != 0) 1123 fatal("%s: buffer error: %s", 1124 __func__, ssh_err(r)); 1125 free(s); 1126 continue; 1127 1128 case 'C': 1129 if (c && c->ctl_chan != -1) 1130 goto noescape; 1131 process_cmdline(ssh); 1132 continue; 1133 1134 default: 1135 if (ch != efc->escape_char) { 1136 if ((r = sshbuf_put_u8(bin, 1137 efc->escape_char)) != 0) 1138 fatal("%s: buffer error: %s", 1139 __func__, ssh_err(r)); 1140 bytes++; 1141 } 1142 /* Escaped characters fall through here */ 1143 break; 1144 } 1145 } else { 1146 /* 1147 * The previous character was not an escape char. 1148 * Check if this is an escape. 1149 */ 1150 if (last_was_cr && ch == efc->escape_char) { 1151 /* 1152 * It is. Set the flag and continue to 1153 * next character. 1154 */ 1155 efc->escape_pending = 1; 1156 continue; 1157 } 1158 } 1159 1160 /* 1161 * Normal character. Record whether it was a newline, 1162 * and append it to the buffer. 1163 */ 1164 last_was_cr = (ch == '\r' || ch == '\n'); 1165 if ((r = sshbuf_put_u8(bin, ch)) != 0) 1166 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1167 bytes++; 1168 } 1169 return bytes; 1170 } 1171 1172 /* 1173 * Get packets from the connection input buffer, and process them as long as 1174 * there are packets available. 1175 * 1176 * Any unknown packets received during the actual 1177 * session cause the session to terminate. This is 1178 * intended to make debugging easier since no 1179 * confirmations are sent. Any compatible protocol 1180 * extensions must be negotiated during the 1181 * preparatory phase. 1182 */ 1183 1184 static void 1185 client_process_buffered_input_packets(void) 1186 { 1187 ssh_dispatch_run_fatal(active_state, DISPATCH_NONBLOCK, &quit_pending); 1188 } 1189 1190 /* scan buf[] for '~' before sending data to the peer */ 1191 1192 /* Helper: allocate a new escape_filter_ctx and fill in its escape char */ 1193 void * 1194 client_new_escape_filter_ctx(int escape_char) 1195 { 1196 struct escape_filter_ctx *ret; 1197 1198 ret = xcalloc(1, sizeof(*ret)); 1199 ret->escape_pending = 0; 1200 ret->escape_char = escape_char; 1201 return (void *)ret; 1202 } 1203 1204 /* Free the escape filter context on channel free */ 1205 void 1206 client_filter_cleanup(struct ssh *ssh, int cid, void *ctx) 1207 { 1208 free(ctx); 1209 } 1210 1211 int 1212 client_simple_escape_filter(struct ssh *ssh, Channel *c, char *buf, int len) 1213 { 1214 if (c->extended_usage != CHAN_EXTENDED_WRITE) 1215 return 0; 1216 1217 return process_escapes(ssh, c, c->input, c->output, c->extended, 1218 buf, len); 1219 } 1220 1221 static void 1222 client_channel_closed(struct ssh *ssh, int id, void *arg) 1223 { 1224 channel_cancel_cleanup(ssh, id); 1225 session_closed = 1; 1226 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1227 } 1228 1229 /* 1230 * Implements the interactive session with the server. This is called after 1231 * the user has been authenticated, and a command has been started on the 1232 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character 1233 * used as an escape character for terminating or suspending the session. 1234 */ 1235 int 1236 client_loop(struct ssh *ssh, int have_pty, int escape_char_arg, 1237 int ssh2_chan_id) 1238 { 1239 fd_set *readset = NULL, *writeset = NULL; 1240 double start_time, total_time; 1241 int r, max_fd = 0, max_fd2 = 0, len; 1242 u_int64_t ibytes, obytes; 1243 u_int nalloc = 0; 1244 char buf[100]; 1245 1246 debug("Entering interactive session."); 1247 1248 if (options.control_master && 1249 !option_clear_or_none(options.control_path)) { 1250 debug("pledge: id"); 1251 if (pledge("stdio rpath wpath cpath unix inet dns recvfd proc exec id tty", 1252 NULL) == -1) 1253 fatal("%s pledge(): %s", __func__, strerror(errno)); 1254 1255 } else if (options.forward_x11 || options.permit_local_command) { 1256 debug("pledge: exec"); 1257 if (pledge("stdio rpath wpath cpath unix inet dns proc exec tty", 1258 NULL) == -1) 1259 fatal("%s pledge(): %s", __func__, strerror(errno)); 1260 1261 } else if (options.update_hostkeys) { 1262 debug("pledge: filesystem full"); 1263 if (pledge("stdio rpath wpath cpath unix inet dns proc tty", 1264 NULL) == -1) 1265 fatal("%s pledge(): %s", __func__, strerror(errno)); 1266 1267 } else if (!option_clear_or_none(options.proxy_command) || 1268 fork_after_authentication_flag) { 1269 debug("pledge: proc"); 1270 if (pledge("stdio cpath unix inet dns proc tty", NULL) == -1) 1271 fatal("%s pledge(): %s", __func__, strerror(errno)); 1272 1273 } else { 1274 debug("pledge: network"); 1275 if (pledge("stdio unix inet dns proc tty", NULL) == -1) 1276 fatal("%s pledge(): %s", __func__, strerror(errno)); 1277 } 1278 1279 start_time = monotime_double(); 1280 1281 /* Initialize variables. */ 1282 last_was_cr = 1; 1283 exit_status = -1; 1284 connection_in = packet_get_connection_in(); 1285 connection_out = packet_get_connection_out(); 1286 max_fd = MAXIMUM(connection_in, connection_out); 1287 1288 quit_pending = 0; 1289 1290 /* Initialize buffer. */ 1291 if ((stderr_buffer = sshbuf_new()) == NULL) 1292 fatal("%s: sshbuf_new failed", __func__); 1293 1294 client_init_dispatch(); 1295 1296 /* 1297 * Set signal handlers, (e.g. to restore non-blocking mode) 1298 * but don't overwrite SIG_IGN, matches behaviour from rsh(1) 1299 */ 1300 if (signal(SIGHUP, SIG_IGN) != SIG_IGN) 1301 signal(SIGHUP, signal_handler); 1302 if (signal(SIGINT, SIG_IGN) != SIG_IGN) 1303 signal(SIGINT, signal_handler); 1304 if (signal(SIGQUIT, SIG_IGN) != SIG_IGN) 1305 signal(SIGQUIT, signal_handler); 1306 if (signal(SIGTERM, SIG_IGN) != SIG_IGN) 1307 signal(SIGTERM, signal_handler); 1308 signal(SIGWINCH, window_change_handler); 1309 1310 if (have_pty) 1311 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1312 1313 session_ident = ssh2_chan_id; 1314 if (session_ident != -1) { 1315 if (escape_char_arg != SSH_ESCAPECHAR_NONE) { 1316 channel_register_filter(ssh, session_ident, 1317 client_simple_escape_filter, NULL, 1318 client_filter_cleanup, 1319 client_new_escape_filter_ctx( 1320 escape_char_arg)); 1321 } 1322 channel_register_cleanup(ssh, session_ident, 1323 client_channel_closed, 0); 1324 } 1325 1326 /* Main loop of the client for the interactive session mode. */ 1327 while (!quit_pending) { 1328 1329 /* Process buffered packets sent by the server. */ 1330 client_process_buffered_input_packets(); 1331 1332 if (session_closed && !channel_still_open(ssh)) 1333 break; 1334 1335 if (ssh_packet_is_rekeying(ssh)) { 1336 debug("rekeying in progress"); 1337 } else if (need_rekeying) { 1338 /* manual rekey request */ 1339 debug("need rekeying"); 1340 if ((r = kex_start_rekex(ssh)) != 0) 1341 fatal("%s: kex_start_rekex: %s", __func__, 1342 ssh_err(r)); 1343 need_rekeying = 0; 1344 } else { 1345 /* 1346 * Make packets from buffered channel data, and 1347 * enqueue them for sending to the server. 1348 */ 1349 if (packet_not_very_much_data_to_write()) 1350 channel_output_poll(ssh); 1351 1352 /* 1353 * Check if the window size has changed, and buffer a 1354 * message about it to the server if so. 1355 */ 1356 client_check_window_change(ssh); 1357 1358 if (quit_pending) 1359 break; 1360 } 1361 /* 1362 * Wait until we have something to do (something becomes 1363 * available on one of the descriptors). 1364 */ 1365 max_fd2 = max_fd; 1366 client_wait_until_can_do_something(ssh, &readset, &writeset, 1367 &max_fd2, &nalloc, ssh_packet_is_rekeying(ssh)); 1368 1369 if (quit_pending) 1370 break; 1371 1372 /* Do channel operations unless rekeying in progress. */ 1373 if (!ssh_packet_is_rekeying(ssh)) 1374 channel_after_select(ssh, readset, writeset); 1375 1376 /* Buffer input from the connection. */ 1377 client_process_net_input(readset); 1378 1379 if (quit_pending) 1380 break; 1381 1382 /* 1383 * Send as much buffered packet data as possible to the 1384 * sender. 1385 */ 1386 if (FD_ISSET(connection_out, writeset)) 1387 packet_write_poll(); 1388 1389 /* 1390 * If we are a backgrounded control master, and the 1391 * timeout has expired without any active client 1392 * connections, then quit. 1393 */ 1394 if (control_persist_exit_time > 0) { 1395 if (monotime() >= control_persist_exit_time) { 1396 debug("ControlPersist timeout expired"); 1397 break; 1398 } 1399 } 1400 } 1401 free(readset); 1402 free(writeset); 1403 1404 /* Terminate the session. */ 1405 1406 /* Stop watching for window change. */ 1407 signal(SIGWINCH, SIG_DFL); 1408 1409 packet_start(SSH2_MSG_DISCONNECT); 1410 packet_put_int(SSH2_DISCONNECT_BY_APPLICATION); 1411 packet_put_cstring("disconnected by user"); 1412 packet_put_cstring(""); /* language tag */ 1413 packet_send(); 1414 packet_write_wait(); 1415 1416 channel_free_all(ssh); 1417 1418 if (have_pty) 1419 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1420 1421 /* restore blocking io */ 1422 if (!isatty(fileno(stdin))) 1423 unset_nonblock(fileno(stdin)); 1424 if (!isatty(fileno(stdout))) 1425 unset_nonblock(fileno(stdout)); 1426 if (!isatty(fileno(stderr))) 1427 unset_nonblock(fileno(stderr)); 1428 1429 /* 1430 * If there was no shell or command requested, there will be no remote 1431 * exit status to be returned. In that case, clear error code if the 1432 * connection was deliberately terminated at this end. 1433 */ 1434 if (no_shell_flag && received_signal == SIGTERM) { 1435 received_signal = 0; 1436 exit_status = 0; 1437 } 1438 1439 if (received_signal) { 1440 verbose("Killed by signal %d.", (int) received_signal); 1441 cleanup_exit(0); 1442 } 1443 1444 /* 1445 * In interactive mode (with pseudo tty) display a message indicating 1446 * that the connection has been closed. 1447 */ 1448 if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) { 1449 if ((r = sshbuf_putf(stderr_buffer, 1450 "Connection to %.64s closed.\r\n", host)) != 0) 1451 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1452 } 1453 1454 /* Output any buffered data for stderr. */ 1455 if (sshbuf_len(stderr_buffer) > 0) { 1456 len = atomicio(vwrite, fileno(stderr), 1457 (u_char *)sshbuf_ptr(stderr_buffer), 1458 sshbuf_len(stderr_buffer)); 1459 if (len < 0 || (u_int)len != sshbuf_len(stderr_buffer)) 1460 error("Write failed flushing stderr buffer."); 1461 else if ((r = sshbuf_consume(stderr_buffer, len)) != 0) 1462 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1463 } 1464 1465 /* Clear and free any buffers. */ 1466 explicit_bzero(buf, sizeof(buf)); 1467 sshbuf_free(stderr_buffer); 1468 1469 /* Report bytes transferred, and transfer rates. */ 1470 total_time = monotime_double() - start_time; 1471 packet_get_bytes(&ibytes, &obytes); 1472 verbose("Transferred: sent %llu, received %llu bytes, in %.1f seconds", 1473 (unsigned long long)obytes, (unsigned long long)ibytes, total_time); 1474 if (total_time > 0) 1475 verbose("Bytes per second: sent %.1f, received %.1f", 1476 obytes / total_time, ibytes / total_time); 1477 /* Return the exit status of the program. */ 1478 debug("Exit status %d", exit_status); 1479 return exit_status; 1480 } 1481 1482 /*********/ 1483 1484 static Channel * 1485 client_request_forwarded_tcpip(struct ssh *ssh, const char *request_type, 1486 int rchan, u_int rwindow, u_int rmaxpack) 1487 { 1488 Channel *c = NULL; 1489 struct sshbuf *b = NULL; 1490 char *listen_address, *originator_address; 1491 u_short listen_port, originator_port; 1492 int r; 1493 1494 /* Get rest of the packet */ 1495 listen_address = packet_get_string(NULL); 1496 listen_port = packet_get_int(); 1497 originator_address = packet_get_string(NULL); 1498 originator_port = packet_get_int(); 1499 packet_check_eom(); 1500 1501 debug("%s: listen %s port %d, originator %s port %d", __func__, 1502 listen_address, listen_port, originator_address, originator_port); 1503 1504 c = channel_connect_by_listen_address(ssh, listen_address, listen_port, 1505 "forwarded-tcpip", originator_address); 1506 1507 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) { 1508 if ((b = sshbuf_new()) == NULL) { 1509 error("%s: alloc reply", __func__); 1510 goto out; 1511 } 1512 /* reconstruct and send to muxclient */ 1513 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 1514 (r = sshbuf_put_u8(b, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1515 (r = sshbuf_put_cstring(b, request_type)) != 0 || 1516 (r = sshbuf_put_u32(b, rchan)) != 0 || 1517 (r = sshbuf_put_u32(b, rwindow)) != 0 || 1518 (r = sshbuf_put_u32(b, rmaxpack)) != 0 || 1519 (r = sshbuf_put_cstring(b, listen_address)) != 0 || 1520 (r = sshbuf_put_u32(b, listen_port)) != 0 || 1521 (r = sshbuf_put_cstring(b, originator_address)) != 0 || 1522 (r = sshbuf_put_u32(b, originator_port)) != 0 || 1523 (r = sshbuf_put_stringb(c->output, b)) != 0) { 1524 error("%s: compose for muxclient %s", __func__, 1525 ssh_err(r)); 1526 goto out; 1527 } 1528 } 1529 1530 out: 1531 sshbuf_free(b); 1532 free(originator_address); 1533 free(listen_address); 1534 return c; 1535 } 1536 1537 static Channel * 1538 client_request_forwarded_streamlocal(struct ssh *ssh, 1539 const char *request_type, int rchan) 1540 { 1541 Channel *c = NULL; 1542 char *listen_path; 1543 1544 /* Get the remote path. */ 1545 listen_path = packet_get_string(NULL); 1546 /* XXX: Skip reserved field for now. */ 1547 if (packet_get_string_ptr(NULL) == NULL) 1548 fatal("%s: packet_get_string_ptr failed", __func__); 1549 packet_check_eom(); 1550 1551 debug("%s: %s", __func__, listen_path); 1552 1553 c = channel_connect_by_listen_path(ssh, listen_path, 1554 "forwarded-streamlocal@openssh.com", "forwarded-streamlocal"); 1555 free(listen_path); 1556 return c; 1557 } 1558 1559 static Channel * 1560 client_request_x11(struct ssh *ssh, const char *request_type, int rchan) 1561 { 1562 Channel *c = NULL; 1563 char *originator; 1564 u_short originator_port; 1565 int sock; 1566 1567 if (!options.forward_x11) { 1568 error("Warning: ssh server tried X11 forwarding."); 1569 error("Warning: this is probably a break-in attempt by a " 1570 "malicious server."); 1571 return NULL; 1572 } 1573 if (x11_refuse_time != 0 && (u_int)monotime() >= x11_refuse_time) { 1574 verbose("Rejected X11 connection after ForwardX11Timeout " 1575 "expired"); 1576 return NULL; 1577 } 1578 originator = packet_get_string(NULL); 1579 originator_port = packet_get_int(); 1580 packet_check_eom(); 1581 /* XXX check permission */ 1582 debug("client_request_x11: request from %s %d", originator, 1583 originator_port); 1584 free(originator); 1585 sock = x11_connect_display(ssh); 1586 if (sock < 0) 1587 return NULL; 1588 c = channel_new(ssh, "x11", 1589 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1590 CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); 1591 c->force_drain = 1; 1592 return c; 1593 } 1594 1595 static Channel * 1596 client_request_agent(struct ssh *ssh, const char *request_type, int rchan) 1597 { 1598 Channel *c = NULL; 1599 int r, sock; 1600 1601 if (!options.forward_agent) { 1602 error("Warning: ssh server tried agent forwarding."); 1603 error("Warning: this is probably a break-in attempt by a " 1604 "malicious server."); 1605 return NULL; 1606 } 1607 if ((r = ssh_get_authentication_socket(&sock)) != 0) { 1608 if (r != SSH_ERR_AGENT_NOT_PRESENT) 1609 debug("%s: ssh_get_authentication_socket: %s", 1610 __func__, ssh_err(r)); 1611 return NULL; 1612 } 1613 c = channel_new(ssh, "authentication agent connection", 1614 SSH_CHANNEL_OPEN, sock, sock, -1, 1615 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, 1616 "authentication agent connection", 1); 1617 c->force_drain = 1; 1618 return c; 1619 } 1620 1621 char * 1622 client_request_tun_fwd(struct ssh *ssh, int tun_mode, 1623 int local_tun, int remote_tun) 1624 { 1625 Channel *c; 1626 int fd; 1627 char *ifname = NULL; 1628 1629 if (tun_mode == SSH_TUNMODE_NO) 1630 return 0; 1631 1632 debug("Requesting tun unit %d in mode %d", local_tun, tun_mode); 1633 1634 /* Open local tunnel device */ 1635 if ((fd = tun_open(local_tun, tun_mode, &ifname)) == -1) { 1636 error("Tunnel device open failed."); 1637 return NULL; 1638 } 1639 debug("Tunnel forwarding using interface %s", ifname); 1640 1641 c = channel_new(ssh, "tun", SSH_CHANNEL_OPENING, fd, fd, -1, 1642 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1); 1643 c->datagram = 1; 1644 1645 #if defined(SSH_TUN_FILTER) 1646 if (options.tun_open == SSH_TUNMODE_POINTOPOINT) 1647 channel_register_filter(ssh, c->self, sys_tun_infilter, 1648 sys_tun_outfilter, NULL, NULL); 1649 #endif 1650 1651 packet_start(SSH2_MSG_CHANNEL_OPEN); 1652 packet_put_cstring("tun@openssh.com"); 1653 packet_put_int(c->self); 1654 packet_put_int(c->local_window_max); 1655 packet_put_int(c->local_maxpacket); 1656 packet_put_int(tun_mode); 1657 packet_put_int(remote_tun); 1658 packet_send(); 1659 1660 return ifname; 1661 } 1662 1663 /* XXXX move to generic input handler */ 1664 static int 1665 client_input_channel_open(int type, u_int32_t seq, struct ssh *ssh) 1666 { 1667 Channel *c = NULL; 1668 char *ctype; 1669 int rchan; 1670 u_int rmaxpack, rwindow, len; 1671 1672 ctype = packet_get_string(&len); 1673 rchan = packet_get_int(); 1674 rwindow = packet_get_int(); 1675 rmaxpack = packet_get_int(); 1676 1677 debug("client_input_channel_open: ctype %s rchan %d win %d max %d", 1678 ctype, rchan, rwindow, rmaxpack); 1679 1680 if (strcmp(ctype, "forwarded-tcpip") == 0) { 1681 c = client_request_forwarded_tcpip(ssh, ctype, rchan, rwindow, 1682 rmaxpack); 1683 } else if (strcmp(ctype, "forwarded-streamlocal@openssh.com") == 0) { 1684 c = client_request_forwarded_streamlocal(ssh, ctype, rchan); 1685 } else if (strcmp(ctype, "x11") == 0) { 1686 c = client_request_x11(ssh, ctype, rchan); 1687 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) { 1688 c = client_request_agent(ssh, ctype, rchan); 1689 } 1690 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) { 1691 debug3("proxied to downstream: %s", ctype); 1692 } else if (c != NULL) { 1693 debug("confirm %s", ctype); 1694 c->remote_id = rchan; 1695 c->have_remote_id = 1; 1696 c->remote_window = rwindow; 1697 c->remote_maxpacket = rmaxpack; 1698 if (c->type != SSH_CHANNEL_CONNECTING) { 1699 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); 1700 packet_put_int(c->remote_id); 1701 packet_put_int(c->self); 1702 packet_put_int(c->local_window); 1703 packet_put_int(c->local_maxpacket); 1704 packet_send(); 1705 } 1706 } else { 1707 debug("failure %s", ctype); 1708 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); 1709 packet_put_int(rchan); 1710 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED); 1711 packet_put_cstring("open failed"); 1712 packet_put_cstring(""); 1713 packet_send(); 1714 } 1715 free(ctype); 1716 return 0; 1717 } 1718 1719 static int 1720 client_input_channel_req(int type, u_int32_t seq, struct ssh *ssh) 1721 { 1722 Channel *c = NULL; 1723 int exitval, id, reply, success = 0; 1724 char *rtype; 1725 1726 id = packet_get_int(); 1727 c = channel_lookup(ssh, id); 1728 if (channel_proxy_upstream(c, type, seq, ssh)) 1729 return 0; 1730 rtype = packet_get_string(NULL); 1731 reply = packet_get_char(); 1732 1733 debug("client_input_channel_req: channel %d rtype %s reply %d", 1734 id, rtype, reply); 1735 1736 if (id == -1) { 1737 error("client_input_channel_req: request for channel -1"); 1738 } else if (c == NULL) { 1739 error("client_input_channel_req: channel %d: " 1740 "unknown channel", id); 1741 } else if (strcmp(rtype, "eow@openssh.com") == 0) { 1742 packet_check_eom(); 1743 chan_rcvd_eow(ssh, c); 1744 } else if (strcmp(rtype, "exit-status") == 0) { 1745 exitval = packet_get_int(); 1746 if (c->ctl_chan != -1) { 1747 mux_exit_message(ssh, c, exitval); 1748 success = 1; 1749 } else if (id == session_ident) { 1750 /* Record exit value of local session */ 1751 success = 1; 1752 exit_status = exitval; 1753 } else { 1754 /* Probably for a mux channel that has already closed */ 1755 debug("%s: no sink for exit-status on channel %d", 1756 __func__, id); 1757 } 1758 packet_check_eom(); 1759 } 1760 if (reply && c != NULL && !(c->flags & CHAN_CLOSE_SENT)) { 1761 if (!c->have_remote_id) 1762 fatal("%s: channel %d: no remote_id", 1763 __func__, c->self); 1764 packet_start(success ? 1765 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE); 1766 packet_put_int(c->remote_id); 1767 packet_send(); 1768 } 1769 free(rtype); 1770 return 0; 1771 } 1772 1773 struct hostkeys_update_ctx { 1774 /* The hostname and (optionally) IP address string for the server */ 1775 char *host_str, *ip_str; 1776 1777 /* 1778 * Keys received from the server and a flag for each indicating 1779 * whether they already exist in known_hosts. 1780 * keys_seen is filled in by hostkeys_find() and later (for new 1781 * keys) by client_global_hostkeys_private_confirm(). 1782 */ 1783 struct sshkey **keys; 1784 int *keys_seen; 1785 size_t nkeys, nnew; 1786 1787 /* 1788 * Keys that are in known_hosts, but were not present in the update 1789 * from the server (i.e. scheduled to be deleted). 1790 * Filled in by hostkeys_find(). 1791 */ 1792 struct sshkey **old_keys; 1793 size_t nold; 1794 }; 1795 1796 static void 1797 hostkeys_update_ctx_free(struct hostkeys_update_ctx *ctx) 1798 { 1799 size_t i; 1800 1801 if (ctx == NULL) 1802 return; 1803 for (i = 0; i < ctx->nkeys; i++) 1804 sshkey_free(ctx->keys[i]); 1805 free(ctx->keys); 1806 free(ctx->keys_seen); 1807 for (i = 0; i < ctx->nold; i++) 1808 sshkey_free(ctx->old_keys[i]); 1809 free(ctx->old_keys); 1810 free(ctx->host_str); 1811 free(ctx->ip_str); 1812 free(ctx); 1813 } 1814 1815 static int 1816 hostkeys_find(struct hostkey_foreach_line *l, void *_ctx) 1817 { 1818 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 1819 size_t i; 1820 struct sshkey **tmp; 1821 1822 if (l->status != HKF_STATUS_MATCHED || l->key == NULL) 1823 return 0; 1824 1825 /* Mark off keys we've already seen for this host */ 1826 for (i = 0; i < ctx->nkeys; i++) { 1827 if (sshkey_equal(l->key, ctx->keys[i])) { 1828 debug3("%s: found %s key at %s:%ld", __func__, 1829 sshkey_ssh_name(ctx->keys[i]), l->path, l->linenum); 1830 ctx->keys_seen[i] = 1; 1831 return 0; 1832 } 1833 } 1834 /* This line contained a key that not offered by the server */ 1835 debug3("%s: deprecated %s key at %s:%ld", __func__, 1836 sshkey_ssh_name(l->key), l->path, l->linenum); 1837 if ((tmp = recallocarray(ctx->old_keys, ctx->nold, ctx->nold + 1, 1838 sizeof(*ctx->old_keys))) == NULL) 1839 fatal("%s: recallocarray failed nold = %zu", 1840 __func__, ctx->nold); 1841 ctx->old_keys = tmp; 1842 ctx->old_keys[ctx->nold++] = l->key; 1843 l->key = NULL; 1844 1845 return 0; 1846 } 1847 1848 static void 1849 update_known_hosts(struct hostkeys_update_ctx *ctx) 1850 { 1851 int r, was_raw = 0; 1852 int loglevel = options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK ? 1853 SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_VERBOSE; 1854 char *fp, *response; 1855 size_t i; 1856 1857 for (i = 0; i < ctx->nkeys; i++) { 1858 if (ctx->keys_seen[i] != 2) 1859 continue; 1860 if ((fp = sshkey_fingerprint(ctx->keys[i], 1861 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 1862 fatal("%s: sshkey_fingerprint failed", __func__); 1863 do_log2(loglevel, "Learned new hostkey: %s %s", 1864 sshkey_type(ctx->keys[i]), fp); 1865 free(fp); 1866 } 1867 for (i = 0; i < ctx->nold; i++) { 1868 if ((fp = sshkey_fingerprint(ctx->old_keys[i], 1869 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 1870 fatal("%s: sshkey_fingerprint failed", __func__); 1871 do_log2(loglevel, "Deprecating obsolete hostkey: %s %s", 1872 sshkey_type(ctx->old_keys[i]), fp); 1873 free(fp); 1874 } 1875 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) { 1876 if (get_saved_tio() != NULL) { 1877 leave_raw_mode(1); 1878 was_raw = 1; 1879 } 1880 response = NULL; 1881 for (i = 0; !quit_pending && i < 3; i++) { 1882 free(response); 1883 response = read_passphrase("Accept updated hostkeys? " 1884 "(yes/no): ", RP_ECHO); 1885 if (strcasecmp(response, "yes") == 0) 1886 break; 1887 else if (quit_pending || response == NULL || 1888 strcasecmp(response, "no") == 0) { 1889 options.update_hostkeys = 0; 1890 break; 1891 } else { 1892 do_log2(loglevel, "Please enter " 1893 "\"yes\" or \"no\""); 1894 } 1895 } 1896 if (quit_pending || i >= 3 || response == NULL) 1897 options.update_hostkeys = 0; 1898 free(response); 1899 if (was_raw) 1900 enter_raw_mode(1); 1901 } 1902 1903 /* 1904 * Now that all the keys are verified, we can go ahead and replace 1905 * them in known_hosts (assuming SSH_UPDATE_HOSTKEYS_ASK didn't 1906 * cancel the operation). 1907 */ 1908 if (options.update_hostkeys != 0 && 1909 (r = hostfile_replace_entries(options.user_hostfiles[0], 1910 ctx->host_str, ctx->ip_str, ctx->keys, ctx->nkeys, 1911 options.hash_known_hosts, 0, 1912 options.fingerprint_hash)) != 0) 1913 error("%s: hostfile_replace_entries failed: %s", 1914 __func__, ssh_err(r)); 1915 } 1916 1917 static void 1918 client_global_hostkeys_private_confirm(struct ssh *ssh, int type, 1919 u_int32_t seq, void *_ctx) 1920 { 1921 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 1922 size_t i, ndone; 1923 struct sshbuf *signdata; 1924 int r, kexsigtype, use_kexsigtype; 1925 const u_char *sig; 1926 size_t siglen; 1927 1928 if (ctx->nnew == 0) 1929 fatal("%s: ctx->nnew == 0", __func__); /* sanity */ 1930 if (type != SSH2_MSG_REQUEST_SUCCESS) { 1931 error("Server failed to confirm ownership of " 1932 "private host keys"); 1933 hostkeys_update_ctx_free(ctx); 1934 return; 1935 } 1936 kexsigtype = sshkey_type_plain( 1937 sshkey_type_from_name(ssh->kex->hostkey_alg)); 1938 1939 if ((signdata = sshbuf_new()) == NULL) 1940 fatal("%s: sshbuf_new failed", __func__); 1941 /* Don't want to accidentally accept an unbound signature */ 1942 if (ssh->kex->session_id_len == 0) 1943 fatal("%s: ssh->kex->session_id_len == 0", __func__); 1944 /* 1945 * Expect a signature for each of the ctx->nnew private keys we 1946 * haven't seen before. They will be in the same order as the 1947 * ctx->keys where the corresponding ctx->keys_seen[i] == 0. 1948 */ 1949 for (ndone = i = 0; i < ctx->nkeys; i++) { 1950 if (ctx->keys_seen[i]) 1951 continue; 1952 /* Prepare data to be signed: session ID, unique string, key */ 1953 sshbuf_reset(signdata); 1954 if ( (r = sshbuf_put_cstring(signdata, 1955 "hostkeys-prove-00@openssh.com")) != 0 || 1956 (r = sshbuf_put_string(signdata, ssh->kex->session_id, 1957 ssh->kex->session_id_len)) != 0 || 1958 (r = sshkey_puts(ctx->keys[i], signdata)) != 0) 1959 fatal("%s: failed to prepare signature: %s", 1960 __func__, ssh_err(r)); 1961 /* Extract and verify signature */ 1962 if ((r = sshpkt_get_string_direct(ssh, &sig, &siglen)) != 0) { 1963 error("%s: couldn't parse message: %s", 1964 __func__, ssh_err(r)); 1965 goto out; 1966 } 1967 /* 1968 * For RSA keys, prefer to use the signature type negotiated 1969 * during KEX to the default (SHA1). 1970 */ 1971 use_kexsigtype = kexsigtype == KEY_RSA && 1972 sshkey_type_plain(ctx->keys[i]->type) == KEY_RSA; 1973 if ((r = sshkey_verify(ctx->keys[i], sig, siglen, 1974 sshbuf_ptr(signdata), sshbuf_len(signdata), 1975 use_kexsigtype ? ssh->kex->hostkey_alg : NULL, 0)) != 0) { 1976 error("%s: server gave bad signature for %s key %zu", 1977 __func__, sshkey_type(ctx->keys[i]), i); 1978 goto out; 1979 } 1980 /* Key is good. Mark it as 'seen' */ 1981 ctx->keys_seen[i] = 2; 1982 ndone++; 1983 } 1984 if (ndone != ctx->nnew) 1985 fatal("%s: ndone != ctx->nnew (%zu / %zu)", __func__, 1986 ndone, ctx->nnew); /* Shouldn't happen */ 1987 ssh_packet_check_eom(ssh); 1988 1989 /* Make the edits to known_hosts */ 1990 update_known_hosts(ctx); 1991 out: 1992 hostkeys_update_ctx_free(ctx); 1993 } 1994 1995 /* 1996 * Returns non-zero if the key is accepted by HostkeyAlgorithms. 1997 * Made slightly less trivial by the multiple RSA signature algorithm names. 1998 */ 1999 static int 2000 key_accepted_by_hostkeyalgs(const struct sshkey *key) 2001 { 2002 const char *ktype = sshkey_ssh_name(key); 2003 const char *hostkeyalgs = options.hostkeyalgorithms != NULL ? 2004 options.hostkeyalgorithms : KEX_DEFAULT_PK_ALG; 2005 2006 if (key == NULL || key->type == KEY_UNSPEC) 2007 return 0; 2008 if (key->type == KEY_RSA && 2009 (match_pattern_list("rsa-sha2-256", hostkeyalgs, 0) == 1 || 2010 match_pattern_list("rsa-sha2-512", hostkeyalgs, 0) == 1)) 2011 return 1; 2012 return match_pattern_list(ktype, hostkeyalgs, 0) == 1; 2013 } 2014 2015 /* 2016 * Handle hostkeys-00@openssh.com global request to inform the client of all 2017 * the server's hostkeys. The keys are checked against the user's 2018 * HostkeyAlgorithms preference before they are accepted. 2019 */ 2020 static int 2021 client_input_hostkeys(void) 2022 { 2023 struct ssh *ssh = active_state; /* XXX */ 2024 const u_char *blob = NULL; 2025 size_t i, len = 0; 2026 struct sshbuf *buf = NULL; 2027 struct sshkey *key = NULL, **tmp; 2028 int r; 2029 char *fp; 2030 static int hostkeys_seen = 0; /* XXX use struct ssh */ 2031 extern struct sockaddr_storage hostaddr; /* XXX from ssh.c */ 2032 struct hostkeys_update_ctx *ctx = NULL; 2033 2034 if (hostkeys_seen) 2035 fatal("%s: server already sent hostkeys", __func__); 2036 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK && 2037 options.batch_mode) 2038 return 1; /* won't ask in batchmode, so don't even try */ 2039 if (!options.update_hostkeys || options.num_user_hostfiles <= 0) 2040 return 1; 2041 2042 ctx = xcalloc(1, sizeof(*ctx)); 2043 while (ssh_packet_remaining(ssh) > 0) { 2044 sshkey_free(key); 2045 key = NULL; 2046 if ((r = sshpkt_get_string_direct(ssh, &blob, &len)) != 0) { 2047 error("%s: couldn't parse message: %s", 2048 __func__, ssh_err(r)); 2049 goto out; 2050 } 2051 if ((r = sshkey_from_blob(blob, len, &key)) != 0) { 2052 error("%s: parse key: %s", __func__, ssh_err(r)); 2053 goto out; 2054 } 2055 fp = sshkey_fingerprint(key, options.fingerprint_hash, 2056 SSH_FP_DEFAULT); 2057 debug3("%s: received %s key %s", __func__, 2058 sshkey_type(key), fp); 2059 free(fp); 2060 2061 if (!key_accepted_by_hostkeyalgs(key)) { 2062 debug3("%s: %s key not permitted by HostkeyAlgorithms", 2063 __func__, sshkey_ssh_name(key)); 2064 continue; 2065 } 2066 /* Skip certs */ 2067 if (sshkey_is_cert(key)) { 2068 debug3("%s: %s key is a certificate; skipping", 2069 __func__, sshkey_ssh_name(key)); 2070 continue; 2071 } 2072 /* Ensure keys are unique */ 2073 for (i = 0; i < ctx->nkeys; i++) { 2074 if (sshkey_equal(key, ctx->keys[i])) { 2075 error("%s: received duplicated %s host key", 2076 __func__, sshkey_ssh_name(key)); 2077 goto out; 2078 } 2079 } 2080 /* Key is good, record it */ 2081 if ((tmp = recallocarray(ctx->keys, ctx->nkeys, ctx->nkeys + 1, 2082 sizeof(*ctx->keys))) == NULL) 2083 fatal("%s: recallocarray failed nkeys = %zu", 2084 __func__, ctx->nkeys); 2085 ctx->keys = tmp; 2086 ctx->keys[ctx->nkeys++] = key; 2087 key = NULL; 2088 } 2089 2090 if (ctx->nkeys == 0) { 2091 debug("%s: server sent no hostkeys", __func__); 2092 goto out; 2093 } 2094 2095 if ((ctx->keys_seen = calloc(ctx->nkeys, 2096 sizeof(*ctx->keys_seen))) == NULL) 2097 fatal("%s: calloc failed", __func__); 2098 2099 get_hostfile_hostname_ipaddr(host, 2100 options.check_host_ip ? (struct sockaddr *)&hostaddr : NULL, 2101 options.port, &ctx->host_str, 2102 options.check_host_ip ? &ctx->ip_str : NULL); 2103 2104 /* Find which keys we already know about. */ 2105 if ((r = hostkeys_foreach(options.user_hostfiles[0], hostkeys_find, 2106 ctx, ctx->host_str, ctx->ip_str, 2107 HKF_WANT_PARSE_KEY|HKF_WANT_MATCH)) != 0) { 2108 error("%s: hostkeys_foreach failed: %s", __func__, ssh_err(r)); 2109 goto out; 2110 } 2111 2112 /* Figure out if we have any new keys to add */ 2113 ctx->nnew = 0; 2114 for (i = 0; i < ctx->nkeys; i++) { 2115 if (!ctx->keys_seen[i]) 2116 ctx->nnew++; 2117 } 2118 2119 debug3("%s: %zu keys from server: %zu new, %zu retained. %zu to remove", 2120 __func__, ctx->nkeys, ctx->nnew, ctx->nkeys - ctx->nnew, ctx->nold); 2121 2122 if (ctx->nnew == 0 && ctx->nold != 0) { 2123 /* We have some keys to remove. Just do it. */ 2124 update_known_hosts(ctx); 2125 } else if (ctx->nnew != 0) { 2126 /* 2127 * We have received hitherto-unseen keys from the server. 2128 * Ask the server to confirm ownership of the private halves. 2129 */ 2130 debug3("%s: asking server to prove ownership for %zu keys", 2131 __func__, ctx->nnew); 2132 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 2133 (r = sshpkt_put_cstring(ssh, 2134 "hostkeys-prove-00@openssh.com")) != 0 || 2135 (r = sshpkt_put_u8(ssh, 1)) != 0) /* bool: want reply */ 2136 fatal("%s: cannot prepare packet: %s", 2137 __func__, ssh_err(r)); 2138 if ((buf = sshbuf_new()) == NULL) 2139 fatal("%s: sshbuf_new", __func__); 2140 for (i = 0; i < ctx->nkeys; i++) { 2141 if (ctx->keys_seen[i]) 2142 continue; 2143 sshbuf_reset(buf); 2144 if ((r = sshkey_putb(ctx->keys[i], buf)) != 0) 2145 fatal("%s: sshkey_putb: %s", 2146 __func__, ssh_err(r)); 2147 if ((r = sshpkt_put_stringb(ssh, buf)) != 0) 2148 fatal("%s: sshpkt_put_string: %s", 2149 __func__, ssh_err(r)); 2150 } 2151 if ((r = sshpkt_send(ssh)) != 0) 2152 fatal("%s: sshpkt_send: %s", __func__, ssh_err(r)); 2153 client_register_global_confirm( 2154 client_global_hostkeys_private_confirm, ctx); 2155 ctx = NULL; /* will be freed in callback */ 2156 } 2157 2158 /* Success */ 2159 out: 2160 hostkeys_update_ctx_free(ctx); 2161 sshkey_free(key); 2162 sshbuf_free(buf); 2163 /* 2164 * NB. Return success for all cases. The server doesn't need to know 2165 * what the client does with its hosts file. 2166 */ 2167 return 1; 2168 } 2169 2170 static int 2171 client_input_global_request(int type, u_int32_t seq, struct ssh *ssh) 2172 { 2173 char *rtype; 2174 int want_reply; 2175 int success = 0; 2176 2177 rtype = packet_get_cstring(NULL); 2178 want_reply = packet_get_char(); 2179 debug("client_input_global_request: rtype %s want_reply %d", 2180 rtype, want_reply); 2181 if (strcmp(rtype, "hostkeys-00@openssh.com") == 0) 2182 success = client_input_hostkeys(); 2183 if (want_reply) { 2184 packet_start(success ? 2185 SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE); 2186 packet_send(); 2187 packet_write_wait(); 2188 } 2189 free(rtype); 2190 return 0; 2191 } 2192 2193 void 2194 client_session2_setup(struct ssh *ssh, int id, int want_tty, int want_subsystem, 2195 const char *term, struct termios *tiop, int in_fd, struct sshbuf *cmd, 2196 char **env) 2197 { 2198 int i, j, matched, len; 2199 char *name, *val; 2200 Channel *c = NULL; 2201 2202 debug2("%s: id %d", __func__, id); 2203 2204 if ((c = channel_lookup(ssh, id)) == NULL) 2205 fatal("%s: channel %d: unknown channel", __func__, id); 2206 2207 packet_set_interactive(want_tty, 2208 options.ip_qos_interactive, options.ip_qos_bulk); 2209 2210 if (want_tty) { 2211 struct winsize ws; 2212 2213 /* Store window size in the packet. */ 2214 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0) 2215 memset(&ws, 0, sizeof(ws)); 2216 2217 channel_request_start(ssh, id, "pty-req", 1); 2218 client_expect_confirm(ssh, id, "PTY allocation", CONFIRM_TTY); 2219 packet_put_cstring(term != NULL ? term : ""); 2220 packet_put_int((u_int)ws.ws_col); 2221 packet_put_int((u_int)ws.ws_row); 2222 packet_put_int((u_int)ws.ws_xpixel); 2223 packet_put_int((u_int)ws.ws_ypixel); 2224 if (tiop == NULL) 2225 tiop = get_saved_tio(); 2226 ssh_tty_make_modes(ssh, -1, tiop); 2227 packet_send(); 2228 /* XXX wait for reply */ 2229 c->client_tty = 1; 2230 } 2231 2232 /* Transfer any environment variables from client to server */ 2233 if (options.num_send_env != 0 && env != NULL) { 2234 debug("Sending environment."); 2235 for (i = 0; env[i] != NULL; i++) { 2236 /* Split */ 2237 name = xstrdup(env[i]); 2238 if ((val = strchr(name, '=')) == NULL) { 2239 free(name); 2240 continue; 2241 } 2242 *val++ = '\0'; 2243 2244 matched = 0; 2245 for (j = 0; j < options.num_send_env; j++) { 2246 if (match_pattern(name, options.send_env[j])) { 2247 matched = 1; 2248 break; 2249 } 2250 } 2251 if (!matched) { 2252 debug3("Ignored env %s", name); 2253 free(name); 2254 continue; 2255 } 2256 2257 debug("Sending env %s = %s", name, val); 2258 channel_request_start(ssh, id, "env", 0); 2259 packet_put_cstring(name); 2260 packet_put_cstring(val); 2261 packet_send(); 2262 free(name); 2263 } 2264 } 2265 for (i = 0; i < options.num_setenv; i++) { 2266 /* Split */ 2267 name = xstrdup(options.setenv[i]); 2268 if ((val = strchr(name, '=')) == NULL) { 2269 free(name); 2270 continue; 2271 } 2272 *val++ = '\0'; 2273 2274 debug("Setting env %s = %s", name, val); 2275 channel_request_start(ssh, id, "env", 0); 2276 packet_put_cstring(name); 2277 packet_put_cstring(val); 2278 packet_send(); 2279 free(name); 2280 } 2281 2282 len = sshbuf_len(cmd); 2283 if (len > 0) { 2284 if (len > 900) 2285 len = 900; 2286 if (want_subsystem) { 2287 debug("Sending subsystem: %.*s", 2288 len, (const u_char*)sshbuf_ptr(cmd)); 2289 channel_request_start(ssh, id, "subsystem", 1); 2290 client_expect_confirm(ssh, id, "subsystem", 2291 CONFIRM_CLOSE); 2292 } else { 2293 debug("Sending command: %.*s", 2294 len, (const u_char*)sshbuf_ptr(cmd)); 2295 channel_request_start(ssh, id, "exec", 1); 2296 client_expect_confirm(ssh, id, "exec", CONFIRM_CLOSE); 2297 } 2298 packet_put_string(sshbuf_ptr(cmd), sshbuf_len(cmd)); 2299 packet_send(); 2300 } else { 2301 channel_request_start(ssh, id, "shell", 1); 2302 client_expect_confirm(ssh, id, "shell", CONFIRM_CLOSE); 2303 packet_send(); 2304 } 2305 } 2306 2307 static void 2308 client_init_dispatch(void) 2309 { 2310 dispatch_init(&dispatch_protocol_error); 2311 2312 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); 2313 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); 2314 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); 2315 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); 2316 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open); 2317 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 2318 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 2319 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req); 2320 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); 2321 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm); 2322 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm); 2323 dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request); 2324 2325 /* rekeying */ 2326 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); 2327 2328 /* global request reply messages */ 2329 dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply); 2330 dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply); 2331 } 2332 2333 void 2334 client_stop_mux(void) 2335 { 2336 if (options.control_path != NULL && muxserver_sock != -1) 2337 unlink(options.control_path); 2338 /* 2339 * If we are in persist mode, or don't have a shell, signal that we 2340 * should close when all active channels are closed. 2341 */ 2342 if (options.control_persist || no_shell_flag) { 2343 session_closed = 1; 2344 setproctitle("[stopped mux]"); 2345 } 2346 } 2347 2348 /* client specific fatal cleanup */ 2349 void 2350 cleanup_exit(int i) 2351 { 2352 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 2353 leave_non_blocking(); 2354 if (options.control_path != NULL && muxserver_sock != -1) 2355 unlink(options.control_path); 2356 ssh_kill_proxy_command(); 2357 _exit(i); 2358 } 2359