1 /* $OpenBSD: clientloop.c,v 1.344 2020/04/24 02:19:40 dtucker 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 <stdio.h> 81 #include <stdlib.h> 82 #include <string.h> 83 #include <stdarg.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 * If this field is not NULL, the ForwardAgent socket is this path and different 139 * instead of SSH_AUTH_SOCK. 140 */ 141 extern char *forward_agent_sock_path; 142 143 /* 144 * Flag to indicate that we have received a window change signal which has 145 * not yet been processed. This will cause a message indicating the new 146 * window size to be sent to the server a little later. This is volatile 147 * because this is updated in a signal handler. 148 */ 149 static volatile sig_atomic_t received_window_change_signal = 0; 150 static volatile sig_atomic_t received_signal = 0; 151 152 /* Time when backgrounded control master using ControlPersist should exit */ 153 static time_t control_persist_exit_time = 0; 154 155 /* Common data for the client loop code. */ 156 volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */ 157 static int last_was_cr; /* Last character was a newline. */ 158 static int exit_status; /* Used to store the command exit status. */ 159 static struct sshbuf *stderr_buffer; /* Used for final exit message. */ 160 static int connection_in; /* Connection to server (input). */ 161 static int connection_out; /* Connection to server (output). */ 162 static int need_rekeying; /* Set to non-zero if rekeying is requested. */ 163 static int session_closed; /* In SSH2: login session closed. */ 164 static u_int x11_refuse_time; /* If >0, refuse x11 opens after this time. */ 165 166 static void client_init_dispatch(struct ssh *ssh); 167 int session_ident = -1; 168 169 /* Track escape per proto2 channel */ 170 struct escape_filter_ctx { 171 int escape_pending; 172 int escape_char; 173 }; 174 175 /* Context for channel confirmation replies */ 176 struct channel_reply_ctx { 177 const char *request_type; 178 int id; 179 enum confirm_action action; 180 }; 181 182 /* Global request success/failure callbacks */ 183 /* XXX move to struct ssh? */ 184 struct global_confirm { 185 TAILQ_ENTRY(global_confirm) entry; 186 global_confirm_cb *cb; 187 void *ctx; 188 int ref_count; 189 }; 190 TAILQ_HEAD(global_confirms, global_confirm); 191 static struct global_confirms global_confirms = 192 TAILQ_HEAD_INITIALIZER(global_confirms); 193 194 void ssh_process_session2_setup(int, int, int, struct sshbuf *); 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 rmdir(xauthdir); 334 return -1; 335 } 336 337 if (timeout == 0) { 338 /* auth doesn't time out */ 339 xasprintf(&cmd, "%s -f %s generate %s %s " 340 "untrusted 2>%s", 341 xauth_path, xauthfile, display, 342 SSH_X11_PROTO, _PATH_DEVNULL); 343 } else { 344 /* Add some slack to requested expiry */ 345 if (timeout < UINT_MAX - X11_TIMEOUT_SLACK) 346 x11_timeout_real = timeout + 347 X11_TIMEOUT_SLACK; 348 else { 349 /* Don't overflow on long timeouts */ 350 x11_timeout_real = UINT_MAX; 351 } 352 xasprintf(&cmd, "%s -f %s generate %s %s " 353 "untrusted timeout %u 2>%s", 354 xauth_path, xauthfile, display, 355 SSH_X11_PROTO, x11_timeout_real, 356 _PATH_DEVNULL); 357 } 358 debug2("%s: xauth command: %s", __func__, cmd); 359 360 if (timeout != 0 && x11_refuse_time == 0) { 361 now = monotime() + 1; 362 if (UINT_MAX - timeout < now) 363 x11_refuse_time = UINT_MAX; 364 else 365 x11_refuse_time = now + timeout; 366 channel_set_x11_refuse_time(ssh, 367 x11_refuse_time); 368 } 369 if (system(cmd) == 0) 370 generated = 1; 371 free(cmd); 372 } 373 374 /* 375 * When in untrusted mode, we read the cookie only if it was 376 * successfully generated as an untrusted one in the step 377 * above. 378 */ 379 if (trusted || generated) { 380 xasprintf(&cmd, 381 "%s %s%s list %s 2>" _PATH_DEVNULL, 382 xauth_path, 383 generated ? "-f " : "" , 384 generated ? xauthfile : "", 385 display); 386 debug2("x11_get_proto: %s", cmd); 387 f = popen(cmd, "r"); 388 if (f && fgets(line, sizeof(line), f) && 389 sscanf(line, "%*s %511s %511s", proto, data) == 2) 390 got_data = 1; 391 if (f) 392 pclose(f); 393 free(cmd); 394 } 395 } 396 397 if (do_unlink) { 398 unlink(xauthfile); 399 rmdir(xauthdir); 400 } 401 402 /* Don't fall back to fake X11 data for untrusted forwarding */ 403 if (!trusted && !got_data) { 404 error("Warning: untrusted X11 forwarding setup failed: " 405 "xauth key data not generated"); 406 return -1; 407 } 408 409 /* 410 * If we didn't get authentication data, just make up some 411 * data. The forwarding code will check the validity of the 412 * response anyway, and substitute this data. The X11 413 * server, however, will ignore this fake data and use 414 * whatever authentication mechanisms it was using otherwise 415 * for the local connection. 416 */ 417 if (!got_data) { 418 u_int8_t rnd[16]; 419 u_int i; 420 421 logit("Warning: No xauth data; " 422 "using fake authentication data for X11 forwarding."); 423 strlcpy(proto, SSH_X11_PROTO, sizeof proto); 424 arc4random_buf(rnd, sizeof(rnd)); 425 for (i = 0; i < sizeof(rnd); i++) { 426 snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", 427 rnd[i]); 428 } 429 } 430 431 return 0; 432 } 433 434 /* 435 * Checks if the client window has changed, and sends a packet about it to 436 * the server if so. The actual change is detected elsewhere (by a software 437 * interrupt on Unix); this just checks the flag and sends a message if 438 * appropriate. 439 */ 440 441 static void 442 client_check_window_change(struct ssh *ssh) 443 { 444 if (!received_window_change_signal) 445 return; 446 received_window_change_signal = 0; 447 debug2("%s: changed", __func__); 448 channel_send_window_changes(ssh); 449 } 450 451 static int 452 client_global_request_reply(int type, u_int32_t seq, struct ssh *ssh) 453 { 454 struct global_confirm *gc; 455 456 if ((gc = TAILQ_FIRST(&global_confirms)) == NULL) 457 return 0; 458 if (gc->cb != NULL) 459 gc->cb(ssh, type, seq, gc->ctx); 460 if (--gc->ref_count <= 0) { 461 TAILQ_REMOVE(&global_confirms, gc, entry); 462 freezero(gc, sizeof(*gc)); 463 } 464 465 ssh_packet_set_alive_timeouts(ssh, 0); 466 return 0; 467 } 468 469 static void 470 server_alive_check(struct ssh *ssh) 471 { 472 int r; 473 474 if (ssh_packet_inc_alive_timeouts(ssh) > options.server_alive_count_max) { 475 logit("Timeout, server %s not responding.", host); 476 cleanup_exit(255); 477 } 478 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 479 (r = sshpkt_put_cstring(ssh, "keepalive@openssh.com")) != 0 || 480 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* boolean: want reply */ 481 (r = sshpkt_send(ssh)) != 0) 482 fatal("%s: send packet: %s", __func__, ssh_err(r)); 483 /* Insert an empty placeholder to maintain ordering */ 484 client_register_global_confirm(NULL, NULL); 485 } 486 487 /* 488 * Waits until the client can do something (some data becomes available on 489 * one of the file descriptors). 490 */ 491 static void 492 client_wait_until_can_do_something(struct ssh *ssh, 493 fd_set **readsetp, fd_set **writesetp, 494 int *maxfdp, u_int *nallocp, int rekeying) 495 { 496 struct timeval tv, *tvp; 497 int timeout_secs; 498 time_t minwait_secs = 0, server_alive_time = 0, now = monotime(); 499 int r, ret; 500 501 /* Add any selections by the channel mechanism. */ 502 channel_prepare_select(ssh, readsetp, writesetp, maxfdp, 503 nallocp, &minwait_secs); 504 505 /* channel_prepare_select could have closed the last channel */ 506 if (session_closed && !channel_still_open(ssh) && 507 !ssh_packet_have_data_to_write(ssh)) { 508 /* clear mask since we did not call select() */ 509 memset(*readsetp, 0, *nallocp); 510 memset(*writesetp, 0, *nallocp); 511 return; 512 } 513 514 FD_SET(connection_in, *readsetp); 515 516 /* Select server connection if have data to write to the server. */ 517 if (ssh_packet_have_data_to_write(ssh)) 518 FD_SET(connection_out, *writesetp); 519 520 /* 521 * Wait for something to happen. This will suspend the process until 522 * some selected descriptor can be read, written, or has some other 523 * event pending, or a timeout expires. 524 */ 525 526 timeout_secs = INT_MAX; /* we use INT_MAX to mean no timeout */ 527 if (options.server_alive_interval > 0) { 528 timeout_secs = options.server_alive_interval; 529 server_alive_time = now + options.server_alive_interval; 530 } 531 if (options.rekey_interval > 0 && !rekeying) 532 timeout_secs = MINIMUM(timeout_secs, 533 ssh_packet_get_rekey_timeout(ssh)); 534 set_control_persist_exit_time(ssh); 535 if (control_persist_exit_time > 0) { 536 timeout_secs = MINIMUM(timeout_secs, 537 control_persist_exit_time - now); 538 if (timeout_secs < 0) 539 timeout_secs = 0; 540 } 541 if (minwait_secs != 0) 542 timeout_secs = MINIMUM(timeout_secs, (int)minwait_secs); 543 if (timeout_secs == INT_MAX) 544 tvp = NULL; 545 else { 546 tv.tv_sec = timeout_secs; 547 tv.tv_usec = 0; 548 tvp = &tv; 549 } 550 551 ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp); 552 if (ret == -1) { 553 /* 554 * We have to clear the select masks, because we return. 555 * We have to return, because the mainloop checks for the flags 556 * set by the signal handlers. 557 */ 558 memset(*readsetp, 0, *nallocp); 559 memset(*writesetp, 0, *nallocp); 560 561 if (errno == EINTR) 562 return; 563 /* Note: we might still have data in the buffers. */ 564 if ((r = sshbuf_putf(stderr_buffer, 565 "select: %s\r\n", strerror(errno))) != 0) 566 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 567 quit_pending = 1; 568 } else if (ret == 0) { 569 /* 570 * Timeout. Could have been either keepalive or rekeying. 571 * Keepalive we check here, rekeying is checked in clientloop. 572 */ 573 if (server_alive_time != 0 && server_alive_time <= monotime()) 574 server_alive_check(ssh); 575 } 576 577 } 578 579 static void 580 client_suspend_self(struct sshbuf *bin, struct sshbuf *bout, struct sshbuf *berr) 581 { 582 /* Flush stdout and stderr buffers. */ 583 if (sshbuf_len(bout) > 0) 584 atomicio(vwrite, fileno(stdout), sshbuf_mutable_ptr(bout), 585 sshbuf_len(bout)); 586 if (sshbuf_len(berr) > 0) 587 atomicio(vwrite, fileno(stderr), sshbuf_mutable_ptr(berr), 588 sshbuf_len(berr)); 589 590 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 591 592 sshbuf_reset(bin); 593 sshbuf_reset(bout); 594 sshbuf_reset(berr); 595 596 /* Send the suspend signal to the program itself. */ 597 kill(getpid(), SIGTSTP); 598 599 /* Reset window sizes in case they have changed */ 600 received_window_change_signal = 1; 601 602 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 603 } 604 605 static void 606 client_process_net_input(struct ssh *ssh, fd_set *readset) 607 { 608 char buf[SSH_IOBUFSZ]; 609 int r, len; 610 611 /* 612 * Read input from the server, and add any such data to the buffer of 613 * the packet subsystem. 614 */ 615 if (FD_ISSET(connection_in, readset)) { 616 /* Read as much as possible. */ 617 len = read(connection_in, buf, sizeof(buf)); 618 if (len == 0) { 619 /* 620 * Received EOF. The remote host has closed the 621 * connection. 622 */ 623 if ((r = sshbuf_putf(stderr_buffer, 624 "Connection to %.300s closed by remote host.\r\n", 625 host)) != 0) 626 fatal("%s: buffer error: %s", 627 __func__, ssh_err(r)); 628 quit_pending = 1; 629 return; 630 } 631 /* 632 * There is a kernel bug on Solaris that causes select to 633 * sometimes wake up even though there is no data available. 634 */ 635 if (len == -1 && 636 (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK)) 637 len = 0; 638 639 if (len == -1) { 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 ssh_packet_process_incoming(ssh, 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 = ssh_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 ssh_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: send packet: %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 == -1) { 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(struct ssh *ssh) 1177 { 1178 ssh_dispatch_run_fatal(ssh, 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 sendfd 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 = ssh_packet_get_connection_in(ssh); 1276 connection_out = ssh_packet_get_connection_out(ssh); 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(ssh); 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 (ssh_signal(SIGHUP, SIG_IGN) != SIG_IGN) 1292 ssh_signal(SIGHUP, signal_handler); 1293 if (ssh_signal(SIGINT, SIG_IGN) != SIG_IGN) 1294 ssh_signal(SIGINT, signal_handler); 1295 if (ssh_signal(SIGQUIT, SIG_IGN) != SIG_IGN) 1296 ssh_signal(SIGQUIT, signal_handler); 1297 if (ssh_signal(SIGTERM, SIG_IGN) != SIG_IGN) 1298 ssh_signal(SIGTERM, signal_handler); 1299 ssh_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(ssh); 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 (ssh_packet_not_very_much_data_to_write(ssh)) 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(ssh, 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 if ((r = ssh_packet_write_poll(ssh)) != 0) { 1379 sshpkt_fatal(ssh, r, 1380 "%s: ssh_packet_write_poll", __func__); 1381 } 1382 } 1383 1384 /* 1385 * If we are a backgrounded control master, and the 1386 * timeout has expired without any active client 1387 * connections, then quit. 1388 */ 1389 if (control_persist_exit_time > 0) { 1390 if (monotime() >= control_persist_exit_time) { 1391 debug("ControlPersist timeout expired"); 1392 break; 1393 } 1394 } 1395 } 1396 free(readset); 1397 free(writeset); 1398 1399 /* Terminate the session. */ 1400 1401 /* Stop watching for window change. */ 1402 ssh_signal(SIGWINCH, SIG_DFL); 1403 1404 if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 || 1405 (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_BY_APPLICATION)) != 0 || 1406 (r = sshpkt_put_cstring(ssh, "disconnected by user")) != 0 || 1407 (r = sshpkt_put_cstring(ssh, "")) != 0 || /* language tag */ 1408 (r = sshpkt_send(ssh)) != 0 || 1409 (r = ssh_packet_write_wait(ssh)) != 0) 1410 fatal("%s: send disconnect: %s", __func__, ssh_err(r)); 1411 1412 channel_free_all(ssh); 1413 1414 if (have_pty) 1415 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1416 1417 /* restore blocking io */ 1418 if (!isatty(fileno(stdin))) 1419 unset_nonblock(fileno(stdin)); 1420 if (!isatty(fileno(stdout))) 1421 unset_nonblock(fileno(stdout)); 1422 if (!isatty(fileno(stderr))) 1423 unset_nonblock(fileno(stderr)); 1424 1425 /* 1426 * If there was no shell or command requested, there will be no remote 1427 * exit status to be returned. In that case, clear error code if the 1428 * connection was deliberately terminated at this end. 1429 */ 1430 if (no_shell_flag && received_signal == SIGTERM) { 1431 received_signal = 0; 1432 exit_status = 0; 1433 } 1434 1435 if (received_signal) { 1436 verbose("Killed by signal %d.", (int) received_signal); 1437 cleanup_exit(0); 1438 } 1439 1440 /* 1441 * In interactive mode (with pseudo tty) display a message indicating 1442 * that the connection has been closed. 1443 */ 1444 if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) { 1445 if ((r = sshbuf_putf(stderr_buffer, 1446 "Connection to %.64s closed.\r\n", host)) != 0) 1447 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1448 } 1449 1450 /* Output any buffered data for stderr. */ 1451 if (sshbuf_len(stderr_buffer) > 0) { 1452 len = atomicio(vwrite, fileno(stderr), 1453 (u_char *)sshbuf_ptr(stderr_buffer), 1454 sshbuf_len(stderr_buffer)); 1455 if (len < 0 || (u_int)len != sshbuf_len(stderr_buffer)) 1456 error("Write failed flushing stderr buffer."); 1457 else if ((r = sshbuf_consume(stderr_buffer, len)) != 0) 1458 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1459 } 1460 1461 /* Clear and free any buffers. */ 1462 explicit_bzero(buf, sizeof(buf)); 1463 sshbuf_free(stderr_buffer); 1464 1465 /* Report bytes transferred, and transfer rates. */ 1466 total_time = monotime_double() - start_time; 1467 ssh_packet_get_bytes(ssh, &ibytes, &obytes); 1468 verbose("Transferred: sent %llu, received %llu bytes, in %.1f seconds", 1469 (unsigned long long)obytes, (unsigned long long)ibytes, total_time); 1470 if (total_time > 0) 1471 verbose("Bytes per second: sent %.1f, received %.1f", 1472 obytes / total_time, ibytes / total_time); 1473 /* Return the exit status of the program. */ 1474 debug("Exit status %d", exit_status); 1475 return exit_status; 1476 } 1477 1478 /*********/ 1479 1480 static Channel * 1481 client_request_forwarded_tcpip(struct ssh *ssh, const char *request_type, 1482 int rchan, u_int rwindow, u_int rmaxpack) 1483 { 1484 Channel *c = NULL; 1485 struct sshbuf *b = NULL; 1486 char *listen_address, *originator_address; 1487 u_int listen_port, originator_port; 1488 int r; 1489 1490 /* Get rest of the packet */ 1491 if ((r = sshpkt_get_cstring(ssh, &listen_address, NULL)) != 0 || 1492 (r = sshpkt_get_u32(ssh, &listen_port)) != 0 || 1493 (r = sshpkt_get_cstring(ssh, &originator_address, NULL)) != 0 || 1494 (r = sshpkt_get_u32(ssh, &originator_port)) != 0 || 1495 (r = sshpkt_get_end(ssh)) != 0) 1496 fatal("%s: parse packet: %s", __func__, ssh_err(r)); 1497 1498 debug("%s: listen %s port %d, originator %s port %d", __func__, 1499 listen_address, listen_port, originator_address, originator_port); 1500 1501 if (listen_port > 0xffff) 1502 error("%s: invalid listen port", __func__); 1503 else if (originator_port > 0xffff) 1504 error("%s: invalid originator port", __func__); 1505 else { 1506 c = channel_connect_by_listen_address(ssh, 1507 listen_address, listen_port, "forwarded-tcpip", 1508 originator_address); 1509 } 1510 1511 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) { 1512 if ((b = sshbuf_new()) == NULL) { 1513 error("%s: alloc reply", __func__); 1514 goto out; 1515 } 1516 /* reconstruct and send to muxclient */ 1517 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 1518 (r = sshbuf_put_u8(b, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1519 (r = sshbuf_put_cstring(b, request_type)) != 0 || 1520 (r = sshbuf_put_u32(b, rchan)) != 0 || 1521 (r = sshbuf_put_u32(b, rwindow)) != 0 || 1522 (r = sshbuf_put_u32(b, rmaxpack)) != 0 || 1523 (r = sshbuf_put_cstring(b, listen_address)) != 0 || 1524 (r = sshbuf_put_u32(b, listen_port)) != 0 || 1525 (r = sshbuf_put_cstring(b, originator_address)) != 0 || 1526 (r = sshbuf_put_u32(b, originator_port)) != 0 || 1527 (r = sshbuf_put_stringb(c->output, b)) != 0) { 1528 error("%s: compose for muxclient %s", __func__, 1529 ssh_err(r)); 1530 goto out; 1531 } 1532 } 1533 1534 out: 1535 sshbuf_free(b); 1536 free(originator_address); 1537 free(listen_address); 1538 return c; 1539 } 1540 1541 static Channel * 1542 client_request_forwarded_streamlocal(struct ssh *ssh, 1543 const char *request_type, int rchan) 1544 { 1545 Channel *c = NULL; 1546 char *listen_path; 1547 int r; 1548 1549 /* Get the remote path. */ 1550 if ((r = sshpkt_get_cstring(ssh, &listen_path, NULL)) != 0 || 1551 (r = sshpkt_get_string(ssh, NULL, NULL)) != 0 || /* reserved */ 1552 (r = sshpkt_get_end(ssh)) != 0) 1553 fatal("%s: parse packet: %s", __func__, ssh_err(r)); 1554 1555 debug("%s: request: %s", __func__, listen_path); 1556 1557 c = channel_connect_by_listen_path(ssh, listen_path, 1558 "forwarded-streamlocal@openssh.com", "forwarded-streamlocal"); 1559 free(listen_path); 1560 return c; 1561 } 1562 1563 static Channel * 1564 client_request_x11(struct ssh *ssh, const char *request_type, int rchan) 1565 { 1566 Channel *c = NULL; 1567 char *originator; 1568 u_int originator_port; 1569 int r, sock; 1570 1571 if (!options.forward_x11) { 1572 error("Warning: ssh server tried X11 forwarding."); 1573 error("Warning: this is probably a break-in attempt by a " 1574 "malicious server."); 1575 return NULL; 1576 } 1577 if (x11_refuse_time != 0 && (u_int)monotime() >= x11_refuse_time) { 1578 verbose("Rejected X11 connection after ForwardX11Timeout " 1579 "expired"); 1580 return NULL; 1581 } 1582 if ((r = sshpkt_get_cstring(ssh, &originator, NULL)) != 0 || 1583 (r = sshpkt_get_u32(ssh, &originator_port)) != 0 || 1584 (r = sshpkt_get_end(ssh)) != 0) 1585 fatal("%s: parse packet: %s", __func__, ssh_err(r)); 1586 /* XXX check permission */ 1587 /* XXX range check originator port? */ 1588 debug("client_request_x11: request from %s %u", originator, 1589 originator_port); 1590 free(originator); 1591 sock = x11_connect_display(ssh); 1592 if (sock < 0) 1593 return NULL; 1594 c = channel_new(ssh, "x11", 1595 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1596 CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); 1597 c->force_drain = 1; 1598 return c; 1599 } 1600 1601 static Channel * 1602 client_request_agent(struct ssh *ssh, const char *request_type, int rchan) 1603 { 1604 Channel *c = NULL; 1605 int r, sock; 1606 1607 if (!options.forward_agent) { 1608 error("Warning: ssh server tried agent forwarding."); 1609 error("Warning: this is probably a break-in attempt by a " 1610 "malicious server."); 1611 return NULL; 1612 } 1613 if (forward_agent_sock_path == NULL) { 1614 r = ssh_get_authentication_socket(&sock); 1615 } else { 1616 r = ssh_get_authentication_socket_path(forward_agent_sock_path, &sock); 1617 } 1618 if (r != 0) { 1619 if (r != SSH_ERR_AGENT_NOT_PRESENT) 1620 debug("%s: ssh_get_authentication_socket: %s", 1621 __func__, ssh_err(r)); 1622 return NULL; 1623 } 1624 c = channel_new(ssh, "authentication agent connection", 1625 SSH_CHANNEL_OPEN, sock, sock, -1, 1626 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, 1627 "authentication agent connection", 1); 1628 c->force_drain = 1; 1629 return c; 1630 } 1631 1632 char * 1633 client_request_tun_fwd(struct ssh *ssh, int tun_mode, 1634 int local_tun, int remote_tun, channel_open_fn *cb, void *cbctx) 1635 { 1636 Channel *c; 1637 int r, fd; 1638 char *ifname = NULL; 1639 1640 if (tun_mode == SSH_TUNMODE_NO) 1641 return 0; 1642 1643 debug("Requesting tun unit %d in mode %d", local_tun, tun_mode); 1644 1645 /* Open local tunnel device */ 1646 if ((fd = tun_open(local_tun, tun_mode, &ifname)) == -1) { 1647 error("Tunnel device open failed."); 1648 return NULL; 1649 } 1650 debug("Tunnel forwarding using interface %s", ifname); 1651 1652 c = channel_new(ssh, "tun", SSH_CHANNEL_OPENING, fd, fd, -1, 1653 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1); 1654 c->datagram = 1; 1655 1656 #if defined(SSH_TUN_FILTER) 1657 if (options.tun_open == SSH_TUNMODE_POINTOPOINT) 1658 channel_register_filter(ssh, c->self, sys_tun_infilter, 1659 sys_tun_outfilter, NULL, NULL); 1660 #endif 1661 1662 if (cb != NULL) 1663 channel_register_open_confirm(ssh, c->self, cb, cbctx); 1664 1665 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1666 (r = sshpkt_put_cstring(ssh, "tun@openssh.com")) != 0 || 1667 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1668 (r = sshpkt_put_u32(ssh, c->local_window_max)) != 0 || 1669 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 1670 (r = sshpkt_put_u32(ssh, tun_mode)) != 0 || 1671 (r = sshpkt_put_u32(ssh, remote_tun)) != 0 || 1672 (r = sshpkt_send(ssh)) != 0) 1673 sshpkt_fatal(ssh, r, "%s: send reply", __func__); 1674 1675 return ifname; 1676 } 1677 1678 /* XXXX move to generic input handler */ 1679 static int 1680 client_input_channel_open(int type, u_int32_t seq, struct ssh *ssh) 1681 { 1682 Channel *c = NULL; 1683 char *ctype = NULL; 1684 int r; 1685 u_int rchan; 1686 size_t len; 1687 u_int rmaxpack, rwindow; 1688 1689 if ((r = sshpkt_get_cstring(ssh, &ctype, &len)) != 0 || 1690 (r = sshpkt_get_u32(ssh, &rchan)) != 0 || 1691 (r = sshpkt_get_u32(ssh, &rwindow)) != 0 || 1692 (r = sshpkt_get_u32(ssh, &rmaxpack)) != 0) 1693 goto out; 1694 1695 debug("client_input_channel_open: ctype %s rchan %d win %d max %d", 1696 ctype, rchan, rwindow, rmaxpack); 1697 1698 if (strcmp(ctype, "forwarded-tcpip") == 0) { 1699 c = client_request_forwarded_tcpip(ssh, ctype, rchan, rwindow, 1700 rmaxpack); 1701 } else if (strcmp(ctype, "forwarded-streamlocal@openssh.com") == 0) { 1702 c = client_request_forwarded_streamlocal(ssh, ctype, rchan); 1703 } else if (strcmp(ctype, "x11") == 0) { 1704 c = client_request_x11(ssh, ctype, rchan); 1705 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) { 1706 c = client_request_agent(ssh, ctype, rchan); 1707 } 1708 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) { 1709 debug3("proxied to downstream: %s", ctype); 1710 } else if (c != NULL) { 1711 debug("confirm %s", ctype); 1712 c->remote_id = rchan; 1713 c->have_remote_id = 1; 1714 c->remote_window = rwindow; 1715 c->remote_maxpacket = rmaxpack; 1716 if (c->type != SSH_CHANNEL_CONNECTING) { 1717 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 1718 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1719 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1720 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1721 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 1722 (r = sshpkt_send(ssh)) != 0) 1723 sshpkt_fatal(ssh, r, "%s: send reply", __func__); 1724 } 1725 } else { 1726 debug("failure %s", ctype); 1727 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || 1728 (r = sshpkt_put_u32(ssh, rchan)) != 0 || 1729 (r = sshpkt_put_u32(ssh, SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED)) != 0 || 1730 (r = sshpkt_put_cstring(ssh, "open failed")) != 0 || 1731 (r = sshpkt_put_cstring(ssh, "")) != 0 || 1732 (r = sshpkt_send(ssh)) != 0) 1733 sshpkt_fatal(ssh, r, "%s: send failure", __func__); 1734 } 1735 r = 0; 1736 out: 1737 free(ctype); 1738 return r; 1739 } 1740 1741 static int 1742 client_input_channel_req(int type, u_int32_t seq, struct ssh *ssh) 1743 { 1744 Channel *c = NULL; 1745 char *rtype = NULL; 1746 u_char reply; 1747 u_int id, exitval; 1748 int r, success = 0; 1749 1750 if ((r = sshpkt_get_u32(ssh, &id)) != 0) 1751 return r; 1752 if (id <= INT_MAX) 1753 c = channel_lookup(ssh, id); 1754 if (channel_proxy_upstream(c, type, seq, ssh)) 1755 return 0; 1756 if ((r = sshpkt_get_cstring(ssh, &rtype, NULL)) != 0 || 1757 (r = sshpkt_get_u8(ssh, &reply)) != 0) 1758 goto out; 1759 1760 debug("client_input_channel_req: channel %u rtype %s reply %d", 1761 id, rtype, reply); 1762 1763 if (c == NULL) { 1764 error("client_input_channel_req: channel %d: " 1765 "unknown channel", id); 1766 } else if (strcmp(rtype, "eow@openssh.com") == 0) { 1767 if ((r = sshpkt_get_end(ssh)) != 0) 1768 goto out; 1769 chan_rcvd_eow(ssh, c); 1770 } else if (strcmp(rtype, "exit-status") == 0) { 1771 if ((r = sshpkt_get_u32(ssh, &exitval)) != 0) 1772 goto out; 1773 if (c->ctl_chan != -1) { 1774 mux_exit_message(ssh, c, exitval); 1775 success = 1; 1776 } else if ((int)id == session_ident) { 1777 /* Record exit value of local session */ 1778 success = 1; 1779 exit_status = exitval; 1780 } else { 1781 /* Probably for a mux channel that has already closed */ 1782 debug("%s: no sink for exit-status on channel %d", 1783 __func__, id); 1784 } 1785 if ((r = sshpkt_get_end(ssh)) != 0) 1786 goto out; 1787 } 1788 if (reply && c != NULL && !(c->flags & CHAN_CLOSE_SENT)) { 1789 if (!c->have_remote_id) 1790 fatal("%s: channel %d: no remote_id", 1791 __func__, c->self); 1792 if ((r = sshpkt_start(ssh, success ? 1793 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE)) != 0 || 1794 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1795 (r = sshpkt_send(ssh)) != 0) 1796 sshpkt_fatal(ssh, r, "%s: send failure", __func__); 1797 } 1798 r = 0; 1799 out: 1800 free(rtype); 1801 return r; 1802 } 1803 1804 struct hostkeys_update_ctx { 1805 /* The hostname and (optionally) IP address string for the server */ 1806 char *host_str, *ip_str; 1807 1808 /* 1809 * Keys received from the server and a flag for each indicating 1810 * whether they already exist in known_hosts. 1811 * keys_seen is filled in by hostkeys_find() and later (for new 1812 * keys) by client_global_hostkeys_private_confirm(). 1813 */ 1814 struct sshkey **keys; 1815 int *keys_seen; 1816 size_t nkeys, nnew; 1817 1818 /* 1819 * Keys that are in known_hosts, but were not present in the update 1820 * from the server (i.e. scheduled to be deleted). 1821 * Filled in by hostkeys_find(). 1822 */ 1823 struct sshkey **old_keys; 1824 size_t nold; 1825 }; 1826 1827 static void 1828 hostkeys_update_ctx_free(struct hostkeys_update_ctx *ctx) 1829 { 1830 size_t i; 1831 1832 if (ctx == NULL) 1833 return; 1834 for (i = 0; i < ctx->nkeys; i++) 1835 sshkey_free(ctx->keys[i]); 1836 free(ctx->keys); 1837 free(ctx->keys_seen); 1838 for (i = 0; i < ctx->nold; i++) 1839 sshkey_free(ctx->old_keys[i]); 1840 free(ctx->old_keys); 1841 free(ctx->host_str); 1842 free(ctx->ip_str); 1843 free(ctx); 1844 } 1845 1846 static int 1847 hostkeys_find(struct hostkey_foreach_line *l, void *_ctx) 1848 { 1849 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 1850 size_t i; 1851 struct sshkey **tmp; 1852 1853 if (l->status != HKF_STATUS_MATCHED || l->key == NULL) 1854 return 0; 1855 1856 /* Mark off keys we've already seen for this host */ 1857 for (i = 0; i < ctx->nkeys; i++) { 1858 if (sshkey_equal(l->key, ctx->keys[i])) { 1859 debug3("%s: found %s key at %s:%ld", __func__, 1860 sshkey_ssh_name(ctx->keys[i]), l->path, l->linenum); 1861 ctx->keys_seen[i] = 1; 1862 return 0; 1863 } 1864 } 1865 /* This line contained a key that not offered by the server */ 1866 debug3("%s: deprecated %s key at %s:%ld", __func__, 1867 sshkey_ssh_name(l->key), l->path, l->linenum); 1868 if ((tmp = recallocarray(ctx->old_keys, ctx->nold, ctx->nold + 1, 1869 sizeof(*ctx->old_keys))) == NULL) 1870 fatal("%s: recallocarray failed nold = %zu", 1871 __func__, ctx->nold); 1872 ctx->old_keys = tmp; 1873 ctx->old_keys[ctx->nold++] = l->key; 1874 l->key = NULL; 1875 1876 return 0; 1877 } 1878 1879 static void 1880 hostkey_change_preamble(LogLevel loglevel) 1881 { 1882 do_log2(loglevel, "The server has updated its host keys."); 1883 do_log2(loglevel, "These changes were verified by the server's " 1884 "existing trusted key."); 1885 } 1886 1887 static void 1888 update_known_hosts(struct hostkeys_update_ctx *ctx) 1889 { 1890 int r, was_raw = 0, first = 1; 1891 int asking = options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK; 1892 LogLevel loglevel = asking ? SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_VERBOSE; 1893 char *fp, *response; 1894 size_t i; 1895 struct stat sb; 1896 1897 for (i = 0; i < ctx->nkeys; i++) { 1898 if (ctx->keys_seen[i] != 2) 1899 continue; 1900 if ((fp = sshkey_fingerprint(ctx->keys[i], 1901 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 1902 fatal("%s: sshkey_fingerprint failed", __func__); 1903 if (first && asking) 1904 hostkey_change_preamble(loglevel); 1905 do_log2(loglevel, "Learned new hostkey: %s %s", 1906 sshkey_type(ctx->keys[i]), fp); 1907 first = 0; 1908 free(fp); 1909 } 1910 for (i = 0; i < ctx->nold; i++) { 1911 if ((fp = sshkey_fingerprint(ctx->old_keys[i], 1912 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 1913 fatal("%s: sshkey_fingerprint failed", __func__); 1914 if (first && asking) 1915 hostkey_change_preamble(loglevel); 1916 do_log2(loglevel, "Deprecating obsolete hostkey: %s %s", 1917 sshkey_type(ctx->old_keys[i]), fp); 1918 first = 0; 1919 free(fp); 1920 } 1921 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) { 1922 if (get_saved_tio() != NULL) { 1923 leave_raw_mode(1); 1924 was_raw = 1; 1925 } 1926 response = NULL; 1927 for (i = 0; !quit_pending && i < 3; i++) { 1928 free(response); 1929 response = read_passphrase("Accept updated hostkeys? " 1930 "(yes/no): ", RP_ECHO); 1931 if (strcasecmp(response, "yes") == 0) 1932 break; 1933 else if (quit_pending || response == NULL || 1934 strcasecmp(response, "no") == 0) { 1935 options.update_hostkeys = 0; 1936 break; 1937 } else { 1938 do_log2(loglevel, "Please enter " 1939 "\"yes\" or \"no\""); 1940 } 1941 } 1942 if (quit_pending || i >= 3 || response == NULL) 1943 options.update_hostkeys = 0; 1944 free(response); 1945 if (was_raw) 1946 enter_raw_mode(1); 1947 } 1948 if (options.update_hostkeys == 0) 1949 return; 1950 /* 1951 * Now that all the keys are verified, we can go ahead and replace 1952 * them in known_hosts (assuming SSH_UPDATE_HOSTKEYS_ASK didn't 1953 * cancel the operation). 1954 */ 1955 for (i = 0; i < options.num_user_hostfiles; i++) { 1956 /* 1957 * NB. keys are only added to hostfiles[0], for the rest we 1958 * just delete the hostname entries. 1959 */ 1960 if (stat(options.user_hostfiles[i], &sb) != 0) { 1961 if (errno == ENOENT) { 1962 debug("%s: known hosts file %s does not exist", 1963 __func__, strerror(errno)); 1964 } else { 1965 error("%s: known hosts file %s inaccessible", 1966 __func__, strerror(errno)); 1967 } 1968 continue; 1969 } 1970 if ((r = hostfile_replace_entries(options.user_hostfiles[i], 1971 ctx->host_str, ctx->ip_str, 1972 i == 0 ? ctx->keys : NULL, i == 0 ? ctx->nkeys : 0, 1973 options.hash_known_hosts, 0, 1974 options.fingerprint_hash)) != 0) { 1975 error("%s: hostfile_replace_entries failed for %s: %s", 1976 __func__, options.user_hostfiles[i], ssh_err(r)); 1977 } 1978 } 1979 } 1980 1981 static void 1982 client_global_hostkeys_private_confirm(struct ssh *ssh, int type, 1983 u_int32_t seq, void *_ctx) 1984 { 1985 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 1986 size_t i, ndone; 1987 struct sshbuf *signdata; 1988 int r, kexsigtype, use_kexsigtype; 1989 const u_char *sig; 1990 size_t siglen; 1991 1992 if (ctx->nnew == 0) 1993 fatal("%s: ctx->nnew == 0", __func__); /* sanity */ 1994 if (type != SSH2_MSG_REQUEST_SUCCESS) { 1995 error("Server failed to confirm ownership of " 1996 "private host keys"); 1997 hostkeys_update_ctx_free(ctx); 1998 return; 1999 } 2000 kexsigtype = sshkey_type_plain( 2001 sshkey_type_from_name(ssh->kex->hostkey_alg)); 2002 2003 if ((signdata = sshbuf_new()) == NULL) 2004 fatal("%s: sshbuf_new failed", __func__); 2005 /* Don't want to accidentally accept an unbound signature */ 2006 if (ssh->kex->session_id_len == 0) 2007 fatal("%s: ssh->kex->session_id_len == 0", __func__); 2008 /* 2009 * Expect a signature for each of the ctx->nnew private keys we 2010 * haven't seen before. They will be in the same order as the 2011 * ctx->keys where the corresponding ctx->keys_seen[i] == 0. 2012 */ 2013 for (ndone = i = 0; i < ctx->nkeys; i++) { 2014 if (ctx->keys_seen[i]) 2015 continue; 2016 /* Prepare data to be signed: session ID, unique string, key */ 2017 sshbuf_reset(signdata); 2018 if ( (r = sshbuf_put_cstring(signdata, 2019 "hostkeys-prove-00@openssh.com")) != 0 || 2020 (r = sshbuf_put_string(signdata, ssh->kex->session_id, 2021 ssh->kex->session_id_len)) != 0 || 2022 (r = sshkey_puts(ctx->keys[i], signdata)) != 0) 2023 fatal("%s: failed to prepare signature: %s", 2024 __func__, ssh_err(r)); 2025 /* Extract and verify signature */ 2026 if ((r = sshpkt_get_string_direct(ssh, &sig, &siglen)) != 0) { 2027 error("%s: couldn't parse message: %s", 2028 __func__, ssh_err(r)); 2029 goto out; 2030 } 2031 /* 2032 * For RSA keys, prefer to use the signature type negotiated 2033 * during KEX to the default (SHA1). 2034 */ 2035 use_kexsigtype = kexsigtype == KEY_RSA && 2036 sshkey_type_plain(ctx->keys[i]->type) == KEY_RSA; 2037 if ((r = sshkey_verify(ctx->keys[i], sig, siglen, 2038 sshbuf_ptr(signdata), sshbuf_len(signdata), 2039 use_kexsigtype ? ssh->kex->hostkey_alg : NULL, 0, 2040 NULL)) != 0) { 2041 error("%s: server gave bad signature for %s key %zu", 2042 __func__, sshkey_type(ctx->keys[i]), i); 2043 goto out; 2044 } 2045 /* Key is good. Mark it as 'seen' */ 2046 ctx->keys_seen[i] = 2; 2047 ndone++; 2048 } 2049 if (ndone != ctx->nnew) 2050 fatal("%s: ndone != ctx->nnew (%zu / %zu)", __func__, 2051 ndone, ctx->nnew); /* Shouldn't happen */ 2052 if ((r = sshpkt_get_end(ssh)) != 0) { 2053 error("%s: protocol error", __func__); 2054 goto out; 2055 } 2056 2057 /* Make the edits to known_hosts */ 2058 update_known_hosts(ctx); 2059 out: 2060 hostkeys_update_ctx_free(ctx); 2061 } 2062 2063 /* 2064 * Returns non-zero if the key is accepted by HostkeyAlgorithms. 2065 * Made slightly less trivial by the multiple RSA signature algorithm names. 2066 */ 2067 static int 2068 key_accepted_by_hostkeyalgs(const struct sshkey *key) 2069 { 2070 const char *ktype = sshkey_ssh_name(key); 2071 const char *hostkeyalgs = options.hostkeyalgorithms; 2072 2073 if (key == NULL || key->type == KEY_UNSPEC) 2074 return 0; 2075 if (key->type == KEY_RSA && 2076 (match_pattern_list("rsa-sha2-256", hostkeyalgs, 0) == 1 || 2077 match_pattern_list("rsa-sha2-512", hostkeyalgs, 0) == 1)) 2078 return 1; 2079 return match_pattern_list(ktype, hostkeyalgs, 0) == 1; 2080 } 2081 2082 /* 2083 * Handle hostkeys-00@openssh.com global request to inform the client of all 2084 * the server's hostkeys. The keys are checked against the user's 2085 * HostkeyAlgorithms preference before they are accepted. 2086 */ 2087 static int 2088 client_input_hostkeys(struct ssh *ssh) 2089 { 2090 const u_char *blob = NULL; 2091 size_t i, len = 0; 2092 struct sshbuf *buf = NULL; 2093 struct sshkey *key = NULL, **tmp; 2094 int r; 2095 char *fp; 2096 static int hostkeys_seen = 0; /* XXX use struct ssh */ 2097 extern struct sockaddr_storage hostaddr; /* XXX from ssh.c */ 2098 struct hostkeys_update_ctx *ctx = NULL; 2099 2100 if (hostkeys_seen) 2101 fatal("%s: server already sent hostkeys", __func__); 2102 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK && 2103 options.batch_mode) 2104 return 1; /* won't ask in batchmode, so don't even try */ 2105 if (!options.update_hostkeys || options.num_user_hostfiles <= 0) 2106 return 1; 2107 2108 ctx = xcalloc(1, sizeof(*ctx)); 2109 while (ssh_packet_remaining(ssh) > 0) { 2110 sshkey_free(key); 2111 key = NULL; 2112 if ((r = sshpkt_get_string_direct(ssh, &blob, &len)) != 0) { 2113 error("%s: couldn't parse message: %s", 2114 __func__, ssh_err(r)); 2115 goto out; 2116 } 2117 if ((r = sshkey_from_blob(blob, len, &key)) != 0) { 2118 do_log2(r == SSH_ERR_KEY_TYPE_UNKNOWN ? 2119 SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_ERROR, 2120 "%s: parse key: %s", __func__, ssh_err(r)); 2121 continue; 2122 } 2123 fp = sshkey_fingerprint(key, options.fingerprint_hash, 2124 SSH_FP_DEFAULT); 2125 debug3("%s: received %s key %s", __func__, 2126 sshkey_type(key), fp); 2127 free(fp); 2128 2129 if (!key_accepted_by_hostkeyalgs(key)) { 2130 debug3("%s: %s key not permitted by HostkeyAlgorithms", 2131 __func__, sshkey_ssh_name(key)); 2132 continue; 2133 } 2134 /* Skip certs */ 2135 if (sshkey_is_cert(key)) { 2136 debug3("%s: %s key is a certificate; skipping", 2137 __func__, sshkey_ssh_name(key)); 2138 continue; 2139 } 2140 /* Ensure keys are unique */ 2141 for (i = 0; i < ctx->nkeys; i++) { 2142 if (sshkey_equal(key, ctx->keys[i])) { 2143 error("%s: received duplicated %s host key", 2144 __func__, sshkey_ssh_name(key)); 2145 goto out; 2146 } 2147 } 2148 /* Key is good, record it */ 2149 if ((tmp = recallocarray(ctx->keys, ctx->nkeys, ctx->nkeys + 1, 2150 sizeof(*ctx->keys))) == NULL) 2151 fatal("%s: recallocarray failed nkeys = %zu", 2152 __func__, ctx->nkeys); 2153 ctx->keys = tmp; 2154 ctx->keys[ctx->nkeys++] = key; 2155 key = NULL; 2156 } 2157 2158 if (ctx->nkeys == 0) { 2159 debug("%s: server sent no hostkeys", __func__); 2160 goto out; 2161 } 2162 2163 if ((ctx->keys_seen = calloc(ctx->nkeys, 2164 sizeof(*ctx->keys_seen))) == NULL) 2165 fatal("%s: calloc failed", __func__); 2166 2167 get_hostfile_hostname_ipaddr(host, 2168 options.check_host_ip ? (struct sockaddr *)&hostaddr : NULL, 2169 options.port, &ctx->host_str, 2170 options.check_host_ip ? &ctx->ip_str : NULL); 2171 2172 /* Find which keys we already know about. */ 2173 for (i = 0; i < options.num_user_hostfiles; i++) { 2174 debug("%s: searching %s for %s / %s", __func__, 2175 options.user_hostfiles[i], ctx->host_str, 2176 ctx->ip_str ? ctx->ip_str : "(none)"); 2177 if ((r = hostkeys_foreach(options.user_hostfiles[i], 2178 hostkeys_find, ctx, ctx->host_str, ctx->ip_str, 2179 HKF_WANT_PARSE_KEY|HKF_WANT_MATCH)) != 0) { 2180 if (r == SSH_ERR_SYSTEM_ERROR && errno == ENOENT) { 2181 debug("%s: hostkeys file %s does not exist", 2182 __func__, options.user_hostfiles[i]); 2183 continue; 2184 } 2185 error("%s: hostkeys_foreach failed for %s: %s", 2186 __func__, options.user_hostfiles[i], ssh_err(r)); 2187 goto out; 2188 } 2189 } 2190 2191 /* Figure out if we have any new keys to add */ 2192 ctx->nnew = 0; 2193 for (i = 0; i < ctx->nkeys; i++) { 2194 if (!ctx->keys_seen[i]) 2195 ctx->nnew++; 2196 } 2197 2198 debug3("%s: %zu keys from server: %zu new, %zu retained. %zu to remove", 2199 __func__, ctx->nkeys, ctx->nnew, ctx->nkeys - ctx->nnew, ctx->nold); 2200 2201 if (ctx->nnew == 0 && ctx->nold != 0) { 2202 /* We have some keys to remove. Just do it. */ 2203 update_known_hosts(ctx); 2204 } else if (ctx->nnew != 0) { 2205 /* 2206 * We have received hitherto-unseen keys from the server. 2207 * Ask the server to confirm ownership of the private halves. 2208 */ 2209 debug3("%s: asking server to prove ownership for %zu keys", 2210 __func__, ctx->nnew); 2211 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 2212 (r = sshpkt_put_cstring(ssh, 2213 "hostkeys-prove-00@openssh.com")) != 0 || 2214 (r = sshpkt_put_u8(ssh, 1)) != 0) /* bool: want reply */ 2215 fatal("%s: cannot prepare packet: %s", 2216 __func__, ssh_err(r)); 2217 if ((buf = sshbuf_new()) == NULL) 2218 fatal("%s: sshbuf_new", __func__); 2219 for (i = 0; i < ctx->nkeys; i++) { 2220 if (ctx->keys_seen[i]) 2221 continue; 2222 sshbuf_reset(buf); 2223 if ((r = sshkey_putb(ctx->keys[i], buf)) != 0) 2224 fatal("%s: sshkey_putb: %s", 2225 __func__, ssh_err(r)); 2226 if ((r = sshpkt_put_stringb(ssh, buf)) != 0) 2227 fatal("%s: sshpkt_put_string: %s", 2228 __func__, ssh_err(r)); 2229 } 2230 if ((r = sshpkt_send(ssh)) != 0) 2231 fatal("%s: sshpkt_send: %s", __func__, ssh_err(r)); 2232 client_register_global_confirm( 2233 client_global_hostkeys_private_confirm, ctx); 2234 ctx = NULL; /* will be freed in callback */ 2235 } 2236 2237 /* Success */ 2238 out: 2239 hostkeys_update_ctx_free(ctx); 2240 sshkey_free(key); 2241 sshbuf_free(buf); 2242 /* 2243 * NB. Return success for all cases. The server doesn't need to know 2244 * what the client does with its hosts file. 2245 */ 2246 return 1; 2247 } 2248 2249 static int 2250 client_input_global_request(int type, u_int32_t seq, struct ssh *ssh) 2251 { 2252 char *rtype; 2253 u_char want_reply; 2254 int r, success = 0; 2255 2256 if ((r = sshpkt_get_cstring(ssh, &rtype, NULL)) != 0 || 2257 (r = sshpkt_get_u8(ssh, &want_reply)) != 0) 2258 goto out; 2259 debug("client_input_global_request: rtype %s want_reply %d", 2260 rtype, want_reply); 2261 if (strcmp(rtype, "hostkeys-00@openssh.com") == 0) 2262 success = client_input_hostkeys(ssh); 2263 if (want_reply) { 2264 if ((r = sshpkt_start(ssh, success ? SSH2_MSG_REQUEST_SUCCESS : 2265 SSH2_MSG_REQUEST_FAILURE)) != 0 || 2266 (r = sshpkt_send(ssh)) != 0 || 2267 (r = ssh_packet_write_wait(ssh)) != 0) 2268 goto out; 2269 } 2270 r = 0; 2271 out: 2272 free(rtype); 2273 return r; 2274 } 2275 2276 void 2277 client_session2_setup(struct ssh *ssh, int id, int want_tty, int want_subsystem, 2278 const char *term, struct termios *tiop, int in_fd, struct sshbuf *cmd, 2279 char **env) 2280 { 2281 int i, j, matched, len, r; 2282 char *name, *val; 2283 Channel *c = NULL; 2284 2285 debug2("%s: id %d", __func__, id); 2286 2287 if ((c = channel_lookup(ssh, id)) == NULL) 2288 fatal("%s: channel %d: unknown channel", __func__, id); 2289 2290 ssh_packet_set_interactive(ssh, want_tty, 2291 options.ip_qos_interactive, options.ip_qos_bulk); 2292 2293 if (want_tty) { 2294 struct winsize ws; 2295 2296 /* Store window size in the packet. */ 2297 if (ioctl(in_fd, TIOCGWINSZ, &ws) == -1) 2298 memset(&ws, 0, sizeof(ws)); 2299 2300 channel_request_start(ssh, id, "pty-req", 1); 2301 client_expect_confirm(ssh, id, "PTY allocation", CONFIRM_TTY); 2302 if ((r = sshpkt_put_cstring(ssh, term != NULL ? term : "")) 2303 != 0 || 2304 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || 2305 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || 2306 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || 2307 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0) 2308 fatal("%s: build packet: %s", __func__, ssh_err(r)); 2309 if (tiop == NULL) 2310 tiop = get_saved_tio(); 2311 ssh_tty_make_modes(ssh, -1, tiop); 2312 if ((r = sshpkt_send(ssh)) != 0) 2313 fatal("%s: send packet: %s", __func__, ssh_err(r)); 2314 /* XXX wait for reply */ 2315 c->client_tty = 1; 2316 } 2317 2318 /* Transfer any environment variables from client to server */ 2319 if (options.num_send_env != 0 && env != NULL) { 2320 debug("Sending environment."); 2321 for (i = 0; env[i] != NULL; i++) { 2322 /* Split */ 2323 name = xstrdup(env[i]); 2324 if ((val = strchr(name, '=')) == NULL) { 2325 free(name); 2326 continue; 2327 } 2328 *val++ = '\0'; 2329 2330 matched = 0; 2331 for (j = 0; j < options.num_send_env; j++) { 2332 if (match_pattern(name, options.send_env[j])) { 2333 matched = 1; 2334 break; 2335 } 2336 } 2337 if (!matched) { 2338 debug3("Ignored env %s", name); 2339 free(name); 2340 continue; 2341 } 2342 2343 debug("Sending env %s = %s", name, val); 2344 channel_request_start(ssh, id, "env", 0); 2345 if ((r = sshpkt_put_cstring(ssh, name)) != 0 || 2346 (r = sshpkt_put_cstring(ssh, val)) != 0 || 2347 (r = sshpkt_send(ssh)) != 0) { 2348 fatal("%s: send packet: %s", 2349 __func__, ssh_err(r)); 2350 } 2351 free(name); 2352 } 2353 } 2354 for (i = 0; i < options.num_setenv; i++) { 2355 /* Split */ 2356 name = xstrdup(options.setenv[i]); 2357 if ((val = strchr(name, '=')) == NULL) { 2358 free(name); 2359 continue; 2360 } 2361 *val++ = '\0'; 2362 2363 debug("Setting env %s = %s", name, val); 2364 channel_request_start(ssh, id, "env", 0); 2365 if ((r = sshpkt_put_cstring(ssh, name)) != 0 || 2366 (r = sshpkt_put_cstring(ssh, val)) != 0 || 2367 (r = sshpkt_send(ssh)) != 0) 2368 fatal("%s: send packet: %s", __func__, ssh_err(r)); 2369 free(name); 2370 } 2371 2372 len = sshbuf_len(cmd); 2373 if (len > 0) { 2374 if (len > 900) 2375 len = 900; 2376 if (want_subsystem) { 2377 debug("Sending subsystem: %.*s", 2378 len, (const u_char*)sshbuf_ptr(cmd)); 2379 channel_request_start(ssh, id, "subsystem", 1); 2380 client_expect_confirm(ssh, id, "subsystem", 2381 CONFIRM_CLOSE); 2382 } else { 2383 debug("Sending command: %.*s", 2384 len, (const u_char*)sshbuf_ptr(cmd)); 2385 channel_request_start(ssh, id, "exec", 1); 2386 client_expect_confirm(ssh, id, "exec", CONFIRM_CLOSE); 2387 } 2388 if ((r = sshpkt_put_stringb(ssh, cmd)) != 0 || 2389 (r = sshpkt_send(ssh)) != 0) 2390 fatal("%s: send command: %s", __func__, ssh_err(r)); 2391 } else { 2392 channel_request_start(ssh, id, "shell", 1); 2393 client_expect_confirm(ssh, id, "shell", CONFIRM_CLOSE); 2394 if ((r = sshpkt_send(ssh)) != 0) { 2395 fatal("%s: send shell request: %s", 2396 __func__, ssh_err(r)); 2397 } 2398 } 2399 } 2400 2401 static void 2402 client_init_dispatch(struct ssh *ssh) 2403 { 2404 ssh_dispatch_init(ssh, &dispatch_protocol_error); 2405 2406 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); 2407 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_DATA, &channel_input_data); 2408 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); 2409 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); 2410 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open); 2411 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 2412 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 2413 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req); 2414 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); 2415 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm); 2416 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm); 2417 ssh_dispatch_set(ssh, SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request); 2418 2419 /* rekeying */ 2420 ssh_dispatch_set(ssh, SSH2_MSG_KEXINIT, &kex_input_kexinit); 2421 2422 /* global request reply messages */ 2423 ssh_dispatch_set(ssh, SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply); 2424 ssh_dispatch_set(ssh, SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply); 2425 } 2426 2427 void 2428 client_stop_mux(void) 2429 { 2430 if (options.control_path != NULL && muxserver_sock != -1) 2431 unlink(options.control_path); 2432 /* 2433 * If we are in persist mode, or don't have a shell, signal that we 2434 * should close when all active channels are closed. 2435 */ 2436 if (options.control_persist || no_shell_flag) { 2437 session_closed = 1; 2438 setproctitle("[stopped mux]"); 2439 } 2440 } 2441 2442 /* client specific fatal cleanup */ 2443 void 2444 cleanup_exit(int i) 2445 { 2446 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 2447 if (options.control_path != NULL && muxserver_sock != -1) 2448 unlink(options.control_path); 2449 ssh_kill_proxy_command(); 2450 _exit(i); 2451 } 2452