1 /* $OpenBSD: clientloop.c,v 1.390 2023/03/08 04:43:12 guenther 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 #ifdef HAVE_POLL_H 80 #include <poll.h> 81 #endif 82 #include <signal.h> 83 #include <stdio.h> 84 #include <stdlib.h> 85 #include <string.h> 86 #include <stdarg.h> 87 #include <termios.h> 88 #include <pwd.h> 89 #include <unistd.h> 90 #include <limits.h> 91 92 #include "openbsd-compat/sys-queue.h" 93 #include "xmalloc.h" 94 #include "ssh.h" 95 #include "ssh2.h" 96 #include "packet.h" 97 #include "sshbuf.h" 98 #include "compat.h" 99 #include "channels.h" 100 #include "dispatch.h" 101 #include "sshkey.h" 102 #include "cipher.h" 103 #include "kex.h" 104 #include "myproposal.h" 105 #include "log.h" 106 #include "misc.h" 107 #include "readconf.h" 108 #include "clientloop.h" 109 #include "sshconnect.h" 110 #include "authfd.h" 111 #include "atomicio.h" 112 #include "sshpty.h" 113 #include "match.h" 114 #include "msg.h" 115 #include "ssherr.h" 116 #include "hostfile.h" 117 118 /* Permitted RSA signature algorithms for UpdateHostkeys proofs */ 119 #define HOSTKEY_PROOF_RSA_ALGS "rsa-sha2-512,rsa-sha2-256" 120 121 /* import options */ 122 extern Options options; 123 124 /* Control socket */ 125 extern int muxserver_sock; /* XXX use mux_client_cleanup() instead */ 126 127 /* 128 * Name of the host we are connecting to. This is the name given on the 129 * command line, or the Hostname specified for the user-supplied name in a 130 * configuration file. 131 */ 132 extern char *host; 133 134 /* 135 * If this field is not NULL, the ForwardAgent socket is this path and different 136 * instead of SSH_AUTH_SOCK. 137 */ 138 extern char *forward_agent_sock_path; 139 140 /* 141 * Flag to indicate that we have received a window change signal which has 142 * not yet been processed. This will cause a message indicating the new 143 * window size to be sent to the server a little later. This is volatile 144 * because this is updated in a signal handler. 145 */ 146 static volatile sig_atomic_t received_window_change_signal = 0; 147 static volatile sig_atomic_t received_signal = 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 time_t x11_refuse_time; /* If >0, refuse x11 opens after this time. */ 162 static time_t server_alive_time; /* Time to do server_alive_check */ 163 static int hostkeys_update_complete; 164 static int session_setup_complete; 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 static void quit_message(const char *fmt, ...) 196 __attribute__((__format__ (printf, 1, 2))); 197 198 static void 199 quit_message(const char *fmt, ...) 200 { 201 char *msg; 202 va_list args; 203 int r; 204 205 va_start(args, fmt); 206 xvasprintf(&msg, fmt, args); 207 va_end(args); 208 209 if ((r = sshbuf_putf(stderr_buffer, "%s\r\n", msg)) != 0) 210 fatal_fr(r, "sshbuf_putf"); 211 quit_pending = 1; 212 } 213 214 /* 215 * Signal handler for the window change signal (SIGWINCH). This just sets a 216 * flag indicating that the window has changed. 217 */ 218 static void 219 window_change_handler(int sig) 220 { 221 received_window_change_signal = 1; 222 } 223 224 /* 225 * Signal handler for signals that cause the program to terminate. These 226 * signals must be trapped to restore terminal modes. 227 */ 228 static void 229 signal_handler(int sig) 230 { 231 received_signal = sig; 232 quit_pending = 1; 233 } 234 235 /* 236 * Sets control_persist_exit_time to the absolute time when the 237 * backgrounded control master should exit due to expiry of the 238 * ControlPersist timeout. Sets it to 0 if we are not a backgrounded 239 * control master process, or if there is no ControlPersist timeout. 240 */ 241 static void 242 set_control_persist_exit_time(struct ssh *ssh) 243 { 244 if (muxserver_sock == -1 || !options.control_persist 245 || options.control_persist_timeout == 0) { 246 /* not using a ControlPersist timeout */ 247 control_persist_exit_time = 0; 248 } else if (channel_still_open(ssh)) { 249 /* some client connections are still open */ 250 if (control_persist_exit_time > 0) 251 debug2_f("cancel scheduled exit"); 252 control_persist_exit_time = 0; 253 } else if (control_persist_exit_time <= 0) { 254 /* a client connection has recently closed */ 255 control_persist_exit_time = monotime() + 256 (time_t)options.control_persist_timeout; 257 debug2_f("schedule exit in %d seconds", 258 options.control_persist_timeout); 259 } 260 /* else we are already counting down to the timeout */ 261 } 262 263 #define SSH_X11_VALID_DISPLAY_CHARS ":/.-_" 264 static int 265 client_x11_display_valid(const char *display) 266 { 267 size_t i, dlen; 268 269 if (display == NULL) 270 return 0; 271 272 dlen = strlen(display); 273 for (i = 0; i < dlen; i++) { 274 if (!isalnum((u_char)display[i]) && 275 strchr(SSH_X11_VALID_DISPLAY_CHARS, display[i]) == NULL) { 276 debug("Invalid character '%c' in DISPLAY", display[i]); 277 return 0; 278 } 279 } 280 return 1; 281 } 282 283 #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1" 284 #define X11_TIMEOUT_SLACK 60 285 int 286 client_x11_get_proto(struct ssh *ssh, const char *display, 287 const char *xauth_path, u_int trusted, u_int timeout, 288 char **_proto, char **_data) 289 { 290 char *cmd, line[512], xdisplay[512]; 291 char xauthfile[PATH_MAX], xauthdir[PATH_MAX]; 292 static char proto[512], data[512]; 293 FILE *f; 294 int got_data = 0, generated = 0, do_unlink = 0, r; 295 struct stat st; 296 u_int now, x11_timeout_real; 297 298 *_proto = proto; 299 *_data = data; 300 proto[0] = data[0] = xauthfile[0] = xauthdir[0] = '\0'; 301 302 if (!client_x11_display_valid(display)) { 303 if (display != NULL) 304 logit("DISPLAY \"%s\" invalid; disabling X11 forwarding", 305 display); 306 return -1; 307 } 308 if (xauth_path != NULL && stat(xauth_path, &st) == -1) { 309 debug("No xauth program."); 310 xauth_path = NULL; 311 } 312 313 if (xauth_path != NULL) { 314 /* 315 * Handle FamilyLocal case where $DISPLAY does 316 * not match an authorization entry. For this we 317 * just try "xauth list unix:displaynum.screennum". 318 * XXX: "localhost" match to determine FamilyLocal 319 * is not perfect. 320 */ 321 if (strncmp(display, "localhost:", 10) == 0) { 322 if ((r = snprintf(xdisplay, sizeof(xdisplay), "unix:%s", 323 display + 10)) < 0 || 324 (size_t)r >= sizeof(xdisplay)) { 325 error_f("display name too long"); 326 return -1; 327 } 328 display = xdisplay; 329 } 330 if (trusted == 0) { 331 /* 332 * Generate an untrusted X11 auth cookie. 333 * 334 * The authentication cookie should briefly outlive 335 * ssh's willingness to forward X11 connections to 336 * avoid nasty fail-open behaviour in the X server. 337 */ 338 mktemp_proto(xauthdir, sizeof(xauthdir)); 339 if (mkdtemp(xauthdir) == NULL) { 340 error_f("mkdtemp: %s", strerror(errno)); 341 return -1; 342 } 343 do_unlink = 1; 344 if ((r = snprintf(xauthfile, sizeof(xauthfile), 345 "%s/xauthfile", xauthdir)) < 0 || 346 (size_t)r >= sizeof(xauthfile)) { 347 error_f("xauthfile path too long"); 348 rmdir(xauthdir); 349 return -1; 350 } 351 352 if (timeout == 0) { 353 /* auth doesn't time out */ 354 xasprintf(&cmd, "%s -f %s generate %s %s " 355 "untrusted 2>%s", 356 xauth_path, xauthfile, display, 357 SSH_X11_PROTO, _PATH_DEVNULL); 358 } else { 359 /* Add some slack to requested expiry */ 360 if (timeout < UINT_MAX - X11_TIMEOUT_SLACK) 361 x11_timeout_real = timeout + 362 X11_TIMEOUT_SLACK; 363 else { 364 /* Don't overflow on long timeouts */ 365 x11_timeout_real = UINT_MAX; 366 } 367 xasprintf(&cmd, "%s -f %s generate %s %s " 368 "untrusted timeout %u 2>%s", 369 xauth_path, xauthfile, display, 370 SSH_X11_PROTO, x11_timeout_real, 371 _PATH_DEVNULL); 372 } 373 debug2_f("xauth command: %s", cmd); 374 375 if (timeout != 0 && x11_refuse_time == 0) { 376 now = monotime() + 1; 377 if (SSH_TIME_T_MAX - timeout < now) 378 x11_refuse_time = SSH_TIME_T_MAX; 379 else 380 x11_refuse_time = now + timeout; 381 channel_set_x11_refuse_time(ssh, 382 x11_refuse_time); 383 } 384 if (system(cmd) == 0) 385 generated = 1; 386 free(cmd); 387 } 388 389 /* 390 * When in untrusted mode, we read the cookie only if it was 391 * successfully generated as an untrusted one in the step 392 * above. 393 */ 394 if (trusted || generated) { 395 xasprintf(&cmd, 396 "%s %s%s list %s 2>" _PATH_DEVNULL, 397 xauth_path, 398 generated ? "-f " : "" , 399 generated ? xauthfile : "", 400 display); 401 debug2("x11_get_proto: %s", cmd); 402 f = popen(cmd, "r"); 403 if (f && fgets(line, sizeof(line), f) && 404 sscanf(line, "%*s %511s %511s", proto, data) == 2) 405 got_data = 1; 406 if (f) 407 pclose(f); 408 free(cmd); 409 } 410 } 411 412 if (do_unlink) { 413 unlink(xauthfile); 414 rmdir(xauthdir); 415 } 416 417 /* Don't fall back to fake X11 data for untrusted forwarding */ 418 if (!trusted && !got_data) { 419 error("Warning: untrusted X11 forwarding setup failed: " 420 "xauth key data not generated"); 421 return -1; 422 } 423 424 /* 425 * If we didn't get authentication data, just make up some 426 * data. The forwarding code will check the validity of the 427 * response anyway, and substitute this data. The X11 428 * server, however, will ignore this fake data and use 429 * whatever authentication mechanisms it was using otherwise 430 * for the local connection. 431 */ 432 if (!got_data) { 433 u_int8_t rnd[16]; 434 u_int i; 435 436 logit("Warning: No xauth data; " 437 "using fake authentication data for X11 forwarding."); 438 strlcpy(proto, SSH_X11_PROTO, sizeof proto); 439 arc4random_buf(rnd, sizeof(rnd)); 440 for (i = 0; i < sizeof(rnd); i++) { 441 snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", 442 rnd[i]); 443 } 444 } 445 446 return 0; 447 } 448 449 /* 450 * Checks if the client window has changed, and sends a packet about it to 451 * the server if so. The actual change is detected elsewhere (by a software 452 * interrupt on Unix); this just checks the flag and sends a message if 453 * appropriate. 454 */ 455 456 static void 457 client_check_window_change(struct ssh *ssh) 458 { 459 if (!received_window_change_signal) 460 return; 461 received_window_change_signal = 0; 462 debug2_f("changed"); 463 channel_send_window_changes(ssh); 464 } 465 466 static int 467 client_global_request_reply(int type, u_int32_t seq, struct ssh *ssh) 468 { 469 struct global_confirm *gc; 470 471 if ((gc = TAILQ_FIRST(&global_confirms)) == NULL) 472 return 0; 473 if (gc->cb != NULL) 474 gc->cb(ssh, type, seq, gc->ctx); 475 if (--gc->ref_count <= 0) { 476 TAILQ_REMOVE(&global_confirms, gc, entry); 477 freezero(gc, sizeof(*gc)); 478 } 479 480 ssh_packet_set_alive_timeouts(ssh, 0); 481 return 0; 482 } 483 484 static void 485 schedule_server_alive_check(void) 486 { 487 if (options.server_alive_interval > 0) 488 server_alive_time = monotime() + options.server_alive_interval; 489 } 490 491 static void 492 server_alive_check(struct ssh *ssh) 493 { 494 int r; 495 496 if (ssh_packet_inc_alive_timeouts(ssh) > options.server_alive_count_max) { 497 logit("Timeout, server %s not responding.", host); 498 cleanup_exit(255); 499 } 500 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 501 (r = sshpkt_put_cstring(ssh, "keepalive@openssh.com")) != 0 || 502 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* boolean: want reply */ 503 (r = sshpkt_send(ssh)) != 0) 504 fatal_fr(r, "send packet"); 505 /* Insert an empty placeholder to maintain ordering */ 506 client_register_global_confirm(NULL, NULL); 507 schedule_server_alive_check(); 508 } 509 510 /* 511 * Waits until the client can do something (some data becomes available on 512 * one of the file descriptors). 513 */ 514 static void 515 client_wait_until_can_do_something(struct ssh *ssh, struct pollfd **pfdp, 516 u_int *npfd_allocp, u_int *npfd_activep, int rekeying, 517 int *conn_in_readyp, int *conn_out_readyp) 518 { 519 struct timespec timeout; 520 int ret; 521 u_int p; 522 523 *conn_in_readyp = *conn_out_readyp = 0; 524 525 /* Prepare channel poll. First two pollfd entries are reserved */ 526 ptimeout_init(&timeout); 527 channel_prepare_poll(ssh, pfdp, npfd_allocp, npfd_activep, 2, &timeout); 528 if (*npfd_activep < 2) 529 fatal_f("bad npfd %u", *npfd_activep); /* shouldn't happen */ 530 531 /* channel_prepare_poll could have closed the last channel */ 532 if (session_closed && !channel_still_open(ssh) && 533 !ssh_packet_have_data_to_write(ssh)) { 534 /* clear events since we did not call poll() */ 535 for (p = 0; p < *npfd_activep; p++) 536 (*pfdp)[p].revents = 0; 537 return; 538 } 539 540 /* Monitor server connection on reserved pollfd entries */ 541 (*pfdp)[0].fd = connection_in; 542 (*pfdp)[0].events = POLLIN; 543 (*pfdp)[1].fd = connection_out; 544 (*pfdp)[1].events = ssh_packet_have_data_to_write(ssh) ? POLLOUT : 0; 545 546 /* 547 * Wait for something to happen. This will suspend the process until 548 * some polled descriptor can be read, written, or has some other 549 * event pending, or a timeout expires. 550 */ 551 set_control_persist_exit_time(ssh); 552 if (control_persist_exit_time > 0) 553 ptimeout_deadline_monotime(&timeout, control_persist_exit_time); 554 if (options.server_alive_interval > 0) 555 ptimeout_deadline_monotime(&timeout, server_alive_time); 556 if (options.rekey_interval > 0 && !rekeying) { 557 ptimeout_deadline_sec(&timeout, 558 ssh_packet_get_rekey_timeout(ssh)); 559 } 560 561 ret = poll(*pfdp, *npfd_activep, ptimeout_get_ms(&timeout)); 562 563 if (ret == -1) { 564 /* 565 * We have to clear the events because we return. 566 * We have to return, because the mainloop checks for the flags 567 * set by the signal handlers. 568 */ 569 for (p = 0; p < *npfd_activep; p++) 570 (*pfdp)[p].revents = 0; 571 if (errno == EINTR) 572 return; 573 /* Note: we might still have data in the buffers. */ 574 quit_message("poll: %s", strerror(errno)); 575 return; 576 } 577 578 *conn_in_readyp = (*pfdp)[0].revents != 0; 579 *conn_out_readyp = (*pfdp)[1].revents != 0; 580 581 if (options.server_alive_interval > 0 && !*conn_in_readyp && 582 monotime() >= server_alive_time) { 583 /* 584 * ServerAlive check is needed. We can't rely on the poll 585 * timing out since traffic on the client side such as port 586 * forwards can keep waking it up. 587 */ 588 server_alive_check(ssh); 589 } 590 } 591 592 static void 593 client_suspend_self(struct sshbuf *bin, struct sshbuf *bout, struct sshbuf *berr) 594 { 595 /* Flush stdout and stderr buffers. */ 596 if (sshbuf_len(bout) > 0) 597 atomicio(vwrite, fileno(stdout), sshbuf_mutable_ptr(bout), 598 sshbuf_len(bout)); 599 if (sshbuf_len(berr) > 0) 600 atomicio(vwrite, fileno(stderr), sshbuf_mutable_ptr(berr), 601 sshbuf_len(berr)); 602 603 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 604 605 sshbuf_reset(bin); 606 sshbuf_reset(bout); 607 sshbuf_reset(berr); 608 609 /* Send the suspend signal to the program itself. */ 610 kill(getpid(), SIGTSTP); 611 612 /* Reset window sizes in case they have changed */ 613 received_window_change_signal = 1; 614 615 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 616 } 617 618 static void 619 client_process_net_input(struct ssh *ssh) 620 { 621 int r; 622 623 /* 624 * Read input from the server, and add any such data to the buffer of 625 * the packet subsystem. 626 */ 627 schedule_server_alive_check(); 628 if ((r = ssh_packet_process_read(ssh, connection_in)) == 0) 629 return; /* success */ 630 if (r == SSH_ERR_SYSTEM_ERROR) { 631 if (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK) 632 return; 633 if (errno == EPIPE) { 634 quit_message("Connection to %s closed by remote host.", 635 host); 636 return; 637 } 638 } 639 quit_message("Read from remote host %s: %s", host, ssh_err(r)); 640 } 641 642 static void 643 client_status_confirm(struct ssh *ssh, int type, Channel *c, void *ctx) 644 { 645 struct channel_reply_ctx *cr = (struct channel_reply_ctx *)ctx; 646 char errmsg[256]; 647 int r, tochan; 648 649 /* 650 * If a TTY was explicitly requested, then a failure to allocate 651 * one is fatal. 652 */ 653 if (cr->action == CONFIRM_TTY && 654 (options.request_tty == REQUEST_TTY_FORCE || 655 options.request_tty == REQUEST_TTY_YES)) 656 cr->action = CONFIRM_CLOSE; 657 658 /* XXX suppress on mux _client_ quietmode */ 659 tochan = options.log_level >= SYSLOG_LEVEL_ERROR && 660 c->ctl_chan != -1 && c->extended_usage == CHAN_EXTENDED_WRITE; 661 662 if (type == SSH2_MSG_CHANNEL_SUCCESS) { 663 debug2("%s request accepted on channel %d", 664 cr->request_type, c->self); 665 } else if (type == SSH2_MSG_CHANNEL_FAILURE) { 666 if (tochan) { 667 snprintf(errmsg, sizeof(errmsg), 668 "%s request failed\r\n", cr->request_type); 669 } else { 670 snprintf(errmsg, sizeof(errmsg), 671 "%s request failed on channel %d", 672 cr->request_type, c->self); 673 } 674 /* If error occurred on primary session channel, then exit */ 675 if (cr->action == CONFIRM_CLOSE && c->self == session_ident) 676 fatal("%s", errmsg); 677 /* 678 * If error occurred on mux client, append to 679 * their stderr. 680 */ 681 if (tochan) { 682 debug3_f("channel %d: mux request: %s", c->self, 683 cr->request_type); 684 if ((r = sshbuf_put(c->extended, errmsg, 685 strlen(errmsg))) != 0) 686 fatal_fr(r, "sshbuf_put"); 687 } else 688 error("%s", errmsg); 689 if (cr->action == CONFIRM_TTY) { 690 /* 691 * If a TTY allocation error occurred, then arrange 692 * for the correct TTY to leave raw mode. 693 */ 694 if (c->self == session_ident) 695 leave_raw_mode(0); 696 else 697 mux_tty_alloc_failed(ssh, c); 698 } else if (cr->action == CONFIRM_CLOSE) { 699 chan_read_failed(ssh, c); 700 chan_write_failed(ssh, c); 701 } 702 } 703 free(cr); 704 } 705 706 static void 707 client_abandon_status_confirm(struct ssh *ssh, Channel *c, void *ctx) 708 { 709 free(ctx); 710 } 711 712 void 713 client_expect_confirm(struct ssh *ssh, int id, const char *request, 714 enum confirm_action action) 715 { 716 struct channel_reply_ctx *cr = xcalloc(1, sizeof(*cr)); 717 718 cr->request_type = request; 719 cr->action = action; 720 721 channel_register_status_confirm(ssh, id, client_status_confirm, 722 client_abandon_status_confirm, cr); 723 } 724 725 void 726 client_register_global_confirm(global_confirm_cb *cb, void *ctx) 727 { 728 struct global_confirm *gc, *last_gc; 729 730 /* Coalesce identical callbacks */ 731 last_gc = TAILQ_LAST(&global_confirms, global_confirms); 732 if (last_gc && last_gc->cb == cb && last_gc->ctx == ctx) { 733 if (++last_gc->ref_count >= INT_MAX) 734 fatal_f("last_gc->ref_count = %d", 735 last_gc->ref_count); 736 return; 737 } 738 739 gc = xcalloc(1, sizeof(*gc)); 740 gc->cb = cb; 741 gc->ctx = ctx; 742 gc->ref_count = 1; 743 TAILQ_INSERT_TAIL(&global_confirms, gc, entry); 744 } 745 746 /* 747 * Returns non-zero if the client is able to handle a hostkeys-00@openssh.com 748 * hostkey update request. 749 */ 750 static int 751 can_update_hostkeys(void) 752 { 753 if (hostkeys_update_complete) 754 return 0; 755 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK && 756 options.batch_mode) 757 return 0; /* won't ask in batchmode, so don't even try */ 758 if (!options.update_hostkeys || options.num_user_hostfiles <= 0) 759 return 0; 760 return 1; 761 } 762 763 static void 764 client_repledge(void) 765 { 766 debug3_f("enter"); 767 768 /* Might be able to tighten pledge now that session is established */ 769 if (options.control_master || options.control_path != NULL || 770 options.forward_x11 || options.fork_after_authentication || 771 can_update_hostkeys() || 772 (session_ident != -1 && !session_setup_complete)) { 773 /* Can't tighten */ 774 return; 775 } 776 /* 777 * LocalCommand and UpdateHostkeys have finished, so can get rid of 778 * filesystem. 779 * 780 * XXX protocol allows a server can to change hostkeys during the 781 * connection at rekey time that could trigger a hostkeys update 782 * but AFAIK no implementations support this. Could improve by 783 * forcing known_hosts to be read-only or via unveil(2). 784 */ 785 if (options.num_local_forwards != 0 || 786 options.num_remote_forwards != 0 || 787 options.num_permitted_remote_opens != 0 || 788 options.enable_escape_commandline != 0) { 789 /* rfwd needs inet */ 790 debug("pledge: network"); 791 if (pledge("stdio unix inet dns proc tty", NULL) == -1) 792 fatal_f("pledge(): %s", strerror(errno)); 793 } else if (options.forward_agent != 0) { 794 /* agent forwarding needs to open $SSH_AUTH_SOCK at will */ 795 debug("pledge: agent"); 796 if (pledge("stdio unix proc tty", NULL) == -1) 797 fatal_f("pledge(): %s", strerror(errno)); 798 } else { 799 debug("pledge: fork"); 800 if (pledge("stdio proc tty", NULL) == -1) 801 fatal_f("pledge(): %s", strerror(errno)); 802 } 803 /* XXX further things to do: 804 * 805 * - might be able to get rid of proc if we kill ~^Z 806 * - ssh -N (no session) 807 * - stdio forwarding 808 * - sessions without tty 809 */ 810 } 811 812 static void 813 process_cmdline(struct ssh *ssh) 814 { 815 void (*handler)(int); 816 char *s, *cmd; 817 int ok, delete = 0, local = 0, remote = 0, dynamic = 0; 818 struct Forward fwd; 819 820 memset(&fwd, 0, sizeof(fwd)); 821 822 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 823 handler = ssh_signal(SIGINT, SIG_IGN); 824 cmd = s = read_passphrase("\r\nssh> ", RP_ECHO); 825 if (s == NULL) 826 goto out; 827 while (isspace((u_char)*s)) 828 s++; 829 if (*s == '-') 830 s++; /* Skip cmdline '-', if any */ 831 if (*s == '\0') 832 goto out; 833 834 if (*s == 'h' || *s == 'H' || *s == '?') { 835 logit("Commands:"); 836 logit(" -L[bind_address:]port:host:hostport " 837 "Request local forward"); 838 logit(" -R[bind_address:]port:host:hostport " 839 "Request remote forward"); 840 logit(" -D[bind_address:]port " 841 "Request dynamic forward"); 842 logit(" -KL[bind_address:]port " 843 "Cancel local forward"); 844 logit(" -KR[bind_address:]port " 845 "Cancel remote forward"); 846 logit(" -KD[bind_address:]port " 847 "Cancel dynamic forward"); 848 if (!options.permit_local_command) 849 goto out; 850 logit(" !args " 851 "Execute local command"); 852 goto out; 853 } 854 855 if (*s == '!' && options.permit_local_command) { 856 s++; 857 ssh_local_cmd(s); 858 goto out; 859 } 860 861 if (*s == 'K') { 862 delete = 1; 863 s++; 864 } 865 if (*s == 'L') 866 local = 1; 867 else if (*s == 'R') 868 remote = 1; 869 else if (*s == 'D') 870 dynamic = 1; 871 else { 872 logit("Invalid command."); 873 goto out; 874 } 875 876 while (isspace((u_char)*++s)) 877 ; 878 879 /* XXX update list of forwards in options */ 880 if (delete) { 881 /* We pass 1 for dynamicfwd to restrict to 1 or 2 fields. */ 882 if (!parse_forward(&fwd, s, 1, 0)) { 883 logit("Bad forwarding close specification."); 884 goto out; 885 } 886 if (remote) 887 ok = channel_request_rforward_cancel(ssh, &fwd) == 0; 888 else if (dynamic) 889 ok = channel_cancel_lport_listener(ssh, &fwd, 890 0, &options.fwd_opts) > 0; 891 else 892 ok = channel_cancel_lport_listener(ssh, &fwd, 893 CHANNEL_CANCEL_PORT_STATIC, 894 &options.fwd_opts) > 0; 895 if (!ok) { 896 logit("Unknown port forwarding."); 897 goto out; 898 } 899 logit("Canceled forwarding."); 900 } else { 901 /* -R specs can be both dynamic or not, so check both. */ 902 if (remote) { 903 if (!parse_forward(&fwd, s, 0, remote) && 904 !parse_forward(&fwd, s, 1, remote)) { 905 logit("Bad remote forwarding specification."); 906 goto out; 907 } 908 } else if (!parse_forward(&fwd, s, dynamic, remote)) { 909 logit("Bad local forwarding specification."); 910 goto out; 911 } 912 if (local || dynamic) { 913 if (!channel_setup_local_fwd_listener(ssh, &fwd, 914 &options.fwd_opts)) { 915 logit("Port forwarding failed."); 916 goto out; 917 } 918 } else { 919 if (channel_request_remote_forwarding(ssh, &fwd) < 0) { 920 logit("Port forwarding failed."); 921 goto out; 922 } 923 } 924 logit("Forwarding port."); 925 } 926 927 out: 928 ssh_signal(SIGINT, handler); 929 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 930 free(cmd); 931 free(fwd.listen_host); 932 free(fwd.listen_path); 933 free(fwd.connect_host); 934 free(fwd.connect_path); 935 } 936 937 /* reasons to suppress output of an escape command in help output */ 938 #define SUPPRESS_NEVER 0 /* never suppress, always show */ 939 #define SUPPRESS_MUXCLIENT 1 /* don't show in mux client sessions */ 940 #define SUPPRESS_MUXMASTER 2 /* don't show in mux master sessions */ 941 #define SUPPRESS_SYSLOG 4 /* don't show when logging to syslog */ 942 #define SUPPRESS_NOCMDLINE 8 /* don't show when cmdline disabled*/ 943 struct escape_help_text { 944 const char *cmd; 945 const char *text; 946 unsigned int flags; 947 }; 948 static struct escape_help_text esc_txt[] = { 949 {".", "terminate session", SUPPRESS_MUXMASTER}, 950 {".", "terminate connection (and any multiplexed sessions)", 951 SUPPRESS_MUXCLIENT}, 952 {"B", "send a BREAK to the remote system", SUPPRESS_NEVER}, 953 {"C", "open a command line", SUPPRESS_MUXCLIENT|SUPPRESS_NOCMDLINE}, 954 {"R", "request rekey", SUPPRESS_NEVER}, 955 {"V/v", "decrease/increase verbosity (LogLevel)", SUPPRESS_MUXCLIENT}, 956 {"^Z", "suspend ssh", SUPPRESS_MUXCLIENT}, 957 {"#", "list forwarded connections", SUPPRESS_NEVER}, 958 {"&", "background ssh (when waiting for connections to terminate)", 959 SUPPRESS_MUXCLIENT}, 960 {"?", "this message", SUPPRESS_NEVER}, 961 }; 962 963 static void 964 print_escape_help(struct sshbuf *b, int escape_char, int mux_client, 965 int using_stderr) 966 { 967 unsigned int i, suppress_flags; 968 int r; 969 970 if ((r = sshbuf_putf(b, 971 "%c?\r\nSupported escape sequences:\r\n", escape_char)) != 0) 972 fatal_fr(r, "sshbuf_putf"); 973 974 suppress_flags = 975 (mux_client ? SUPPRESS_MUXCLIENT : 0) | 976 (mux_client ? 0 : SUPPRESS_MUXMASTER) | 977 (using_stderr ? 0 : SUPPRESS_SYSLOG) | 978 (options.enable_escape_commandline == 0 ? SUPPRESS_NOCMDLINE : 0); 979 980 for (i = 0; i < sizeof(esc_txt)/sizeof(esc_txt[0]); i++) { 981 if (esc_txt[i].flags & suppress_flags) 982 continue; 983 if ((r = sshbuf_putf(b, " %c%-3s - %s\r\n", 984 escape_char, esc_txt[i].cmd, esc_txt[i].text)) != 0) 985 fatal_fr(r, "sshbuf_putf"); 986 } 987 988 if ((r = sshbuf_putf(b, 989 " %c%c - send the escape character by typing it twice\r\n" 990 "(Note that escapes are only recognized immediately after " 991 "newline.)\r\n", escape_char, escape_char)) != 0) 992 fatal_fr(r, "sshbuf_putf"); 993 } 994 995 /* 996 * Process the characters one by one. 997 */ 998 static int 999 process_escapes(struct ssh *ssh, Channel *c, 1000 struct sshbuf *bin, struct sshbuf *bout, struct sshbuf *berr, 1001 char *buf, int len) 1002 { 1003 pid_t pid; 1004 int r, bytes = 0; 1005 u_int i; 1006 u_char ch; 1007 char *s; 1008 struct escape_filter_ctx *efc = c->filter_ctx == NULL ? 1009 NULL : (struct escape_filter_ctx *)c->filter_ctx; 1010 1011 if (c->filter_ctx == NULL) 1012 return 0; 1013 1014 if (len <= 0) 1015 return (0); 1016 1017 for (i = 0; i < (u_int)len; i++) { 1018 /* Get one character at a time. */ 1019 ch = buf[i]; 1020 1021 if (efc->escape_pending) { 1022 /* We have previously seen an escape character. */ 1023 /* Clear the flag now. */ 1024 efc->escape_pending = 0; 1025 1026 /* Process the escaped character. */ 1027 switch (ch) { 1028 case '.': 1029 /* Terminate the connection. */ 1030 if ((r = sshbuf_putf(berr, "%c.\r\n", 1031 efc->escape_char)) != 0) 1032 fatal_fr(r, "sshbuf_putf"); 1033 if (c && c->ctl_chan != -1) { 1034 channel_force_close(ssh, c, 1); 1035 return 0; 1036 } else 1037 quit_pending = 1; 1038 return -1; 1039 1040 case 'Z' - 64: 1041 /* XXX support this for mux clients */ 1042 if (c && c->ctl_chan != -1) { 1043 char b[16]; 1044 noescape: 1045 if (ch == 'Z' - 64) 1046 snprintf(b, sizeof b, "^Z"); 1047 else 1048 snprintf(b, sizeof b, "%c", ch); 1049 if ((r = sshbuf_putf(berr, 1050 "%c%s escape not available to " 1051 "multiplexed sessions\r\n", 1052 efc->escape_char, b)) != 0) 1053 fatal_fr(r, "sshbuf_putf"); 1054 continue; 1055 } 1056 /* Suspend the program. Inform the user */ 1057 if ((r = sshbuf_putf(berr, 1058 "%c^Z [suspend ssh]\r\n", 1059 efc->escape_char)) != 0) 1060 fatal_fr(r, "sshbuf_putf"); 1061 1062 /* Restore terminal modes and suspend. */ 1063 client_suspend_self(bin, bout, berr); 1064 1065 /* We have been continued. */ 1066 continue; 1067 1068 case 'B': 1069 if ((r = sshbuf_putf(berr, 1070 "%cB\r\n", efc->escape_char)) != 0) 1071 fatal_fr(r, "sshbuf_putf"); 1072 channel_request_start(ssh, c->self, "break", 0); 1073 if ((r = sshpkt_put_u32(ssh, 1000)) != 0 || 1074 (r = sshpkt_send(ssh)) != 0) 1075 fatal_fr(r, "send packet"); 1076 continue; 1077 1078 case 'R': 1079 if (ssh->compat & SSH_BUG_NOREKEY) 1080 logit("Server does not " 1081 "support re-keying"); 1082 else 1083 need_rekeying = 1; 1084 continue; 1085 1086 case 'V': 1087 /* FALLTHROUGH */ 1088 case 'v': 1089 if (c && c->ctl_chan != -1) 1090 goto noescape; 1091 if (!log_is_on_stderr()) { 1092 if ((r = sshbuf_putf(berr, 1093 "%c%c [Logging to syslog]\r\n", 1094 efc->escape_char, ch)) != 0) 1095 fatal_fr(r, "sshbuf_putf"); 1096 continue; 1097 } 1098 if (ch == 'V' && options.log_level > 1099 SYSLOG_LEVEL_QUIET) 1100 log_change_level(--options.log_level); 1101 if (ch == 'v' && options.log_level < 1102 SYSLOG_LEVEL_DEBUG3) 1103 log_change_level(++options.log_level); 1104 if ((r = sshbuf_putf(berr, 1105 "%c%c [LogLevel %s]\r\n", 1106 efc->escape_char, ch, 1107 log_level_name(options.log_level))) != 0) 1108 fatal_fr(r, "sshbuf_putf"); 1109 continue; 1110 1111 case '&': 1112 if (c && c->ctl_chan != -1) 1113 goto noescape; 1114 /* 1115 * Detach the program (continue to serve 1116 * connections, but put in background and no 1117 * more new connections). 1118 */ 1119 /* Restore tty modes. */ 1120 leave_raw_mode( 1121 options.request_tty == REQUEST_TTY_FORCE); 1122 1123 /* Stop listening for new connections. */ 1124 channel_stop_listening(ssh); 1125 1126 if ((r = sshbuf_putf(berr, "%c& " 1127 "[backgrounded]\n", efc->escape_char)) != 0) 1128 fatal_fr(r, "sshbuf_putf"); 1129 1130 /* Fork into background. */ 1131 pid = fork(); 1132 if (pid == -1) { 1133 error("fork: %.100s", strerror(errno)); 1134 continue; 1135 } 1136 if (pid != 0) { /* This is the parent. */ 1137 /* The parent just exits. */ 1138 exit(0); 1139 } 1140 /* The child continues serving connections. */ 1141 /* fake EOF on stdin */ 1142 if ((r = sshbuf_put_u8(bin, 4)) != 0) 1143 fatal_fr(r, "sshbuf_put_u8"); 1144 return -1; 1145 case '?': 1146 print_escape_help(berr, efc->escape_char, 1147 (c && c->ctl_chan != -1), 1148 log_is_on_stderr()); 1149 continue; 1150 1151 case '#': 1152 if ((r = sshbuf_putf(berr, "%c#\r\n", 1153 efc->escape_char)) != 0) 1154 fatal_fr(r, "sshbuf_putf"); 1155 s = channel_open_message(ssh); 1156 if ((r = sshbuf_put(berr, s, strlen(s))) != 0) 1157 fatal_fr(r, "sshbuf_put"); 1158 free(s); 1159 continue; 1160 1161 case 'C': 1162 if (c && c->ctl_chan != -1) 1163 goto noescape; 1164 if (options.enable_escape_commandline == 0) { 1165 if ((r = sshbuf_putf(berr, 1166 "commandline disabled\r\n")) != 0) 1167 fatal_fr(r, "sshbuf_putf"); 1168 continue; 1169 } 1170 process_cmdline(ssh); 1171 continue; 1172 1173 default: 1174 if (ch != efc->escape_char) { 1175 if ((r = sshbuf_put_u8(bin, 1176 efc->escape_char)) != 0) 1177 fatal_fr(r, "sshbuf_put_u8"); 1178 bytes++; 1179 } 1180 /* Escaped characters fall through here */ 1181 break; 1182 } 1183 } else { 1184 /* 1185 * The previous character was not an escape char. 1186 * Check if this is an escape. 1187 */ 1188 if (last_was_cr && ch == efc->escape_char) { 1189 /* 1190 * It is. Set the flag and continue to 1191 * next character. 1192 */ 1193 efc->escape_pending = 1; 1194 continue; 1195 } 1196 } 1197 1198 /* 1199 * Normal character. Record whether it was a newline, 1200 * and append it to the buffer. 1201 */ 1202 last_was_cr = (ch == '\r' || ch == '\n'); 1203 if ((r = sshbuf_put_u8(bin, ch)) != 0) 1204 fatal_fr(r, "sshbuf_put_u8"); 1205 bytes++; 1206 } 1207 return bytes; 1208 } 1209 1210 /* 1211 * Get packets from the connection input buffer, and process them as long as 1212 * there are packets available. 1213 * 1214 * Any unknown packets received during the actual 1215 * session cause the session to terminate. This is 1216 * intended to make debugging easier since no 1217 * confirmations are sent. Any compatible protocol 1218 * extensions must be negotiated during the 1219 * preparatory phase. 1220 */ 1221 1222 static void 1223 client_process_buffered_input_packets(struct ssh *ssh) 1224 { 1225 ssh_dispatch_run_fatal(ssh, DISPATCH_NONBLOCK, &quit_pending); 1226 } 1227 1228 /* scan buf[] for '~' before sending data to the peer */ 1229 1230 /* Helper: allocate a new escape_filter_ctx and fill in its escape char */ 1231 void * 1232 client_new_escape_filter_ctx(int escape_char) 1233 { 1234 struct escape_filter_ctx *ret; 1235 1236 ret = xcalloc(1, sizeof(*ret)); 1237 ret->escape_pending = 0; 1238 ret->escape_char = escape_char; 1239 return (void *)ret; 1240 } 1241 1242 /* Free the escape filter context on channel free */ 1243 void 1244 client_filter_cleanup(struct ssh *ssh, int cid, void *ctx) 1245 { 1246 free(ctx); 1247 } 1248 1249 int 1250 client_simple_escape_filter(struct ssh *ssh, Channel *c, char *buf, int len) 1251 { 1252 if (c->extended_usage != CHAN_EXTENDED_WRITE) 1253 return 0; 1254 1255 return process_escapes(ssh, c, c->input, c->output, c->extended, 1256 buf, len); 1257 } 1258 1259 static void 1260 client_channel_closed(struct ssh *ssh, int id, int force, void *arg) 1261 { 1262 channel_cancel_cleanup(ssh, id); 1263 session_closed = 1; 1264 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1265 } 1266 1267 /* 1268 * Implements the interactive session with the server. This is called after 1269 * the user has been authenticated, and a command has been started on the 1270 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character 1271 * used as an escape character for terminating or suspending the session. 1272 */ 1273 int 1274 client_loop(struct ssh *ssh, int have_pty, int escape_char_arg, 1275 int ssh2_chan_id) 1276 { 1277 struct pollfd *pfd = NULL; 1278 u_int npfd_alloc = 0, npfd_active = 0; 1279 double start_time, total_time; 1280 int r, len; 1281 u_int64_t ibytes, obytes; 1282 int conn_in_ready, conn_out_ready; 1283 1284 debug("Entering interactive session."); 1285 session_ident = ssh2_chan_id; 1286 1287 if (options.control_master && 1288 !option_clear_or_none(options.control_path)) { 1289 debug("pledge: id"); 1290 if (pledge("stdio rpath wpath cpath unix inet dns recvfd sendfd proc exec id tty", 1291 NULL) == -1) 1292 fatal_f("pledge(): %s", strerror(errno)); 1293 1294 } else if (options.forward_x11 || options.permit_local_command) { 1295 debug("pledge: exec"); 1296 if (pledge("stdio rpath wpath cpath unix inet dns proc exec tty", 1297 NULL) == -1) 1298 fatal_f("pledge(): %s", strerror(errno)); 1299 1300 } else if (options.update_hostkeys) { 1301 debug("pledge: filesystem"); 1302 if (pledge("stdio rpath wpath cpath unix inet dns proc tty", 1303 NULL) == -1) 1304 fatal_f("pledge(): %s", strerror(errno)); 1305 1306 } else if (!option_clear_or_none(options.proxy_command) || 1307 options.fork_after_authentication) { 1308 debug("pledge: proc"); 1309 if (pledge("stdio cpath unix inet dns proc tty", NULL) == -1) 1310 fatal_f("pledge(): %s", strerror(errno)); 1311 1312 } else { 1313 debug("pledge: network"); 1314 if (pledge("stdio unix inet dns proc tty", NULL) == -1) 1315 fatal_f("pledge(): %s", strerror(errno)); 1316 } 1317 1318 /* might be able to tighten now */ 1319 client_repledge(); 1320 1321 start_time = monotime_double(); 1322 1323 /* Initialize variables. */ 1324 last_was_cr = 1; 1325 exit_status = -1; 1326 connection_in = ssh_packet_get_connection_in(ssh); 1327 connection_out = ssh_packet_get_connection_out(ssh); 1328 1329 quit_pending = 0; 1330 1331 /* Initialize buffer. */ 1332 if ((stderr_buffer = sshbuf_new()) == NULL) 1333 fatal_f("sshbuf_new failed"); 1334 1335 client_init_dispatch(ssh); 1336 1337 /* 1338 * Set signal handlers, (e.g. to restore non-blocking mode) 1339 * but don't overwrite SIG_IGN, matches behaviour from rsh(1) 1340 */ 1341 if (ssh_signal(SIGHUP, SIG_IGN) != SIG_IGN) 1342 ssh_signal(SIGHUP, signal_handler); 1343 if (ssh_signal(SIGINT, SIG_IGN) != SIG_IGN) 1344 ssh_signal(SIGINT, signal_handler); 1345 if (ssh_signal(SIGQUIT, SIG_IGN) != SIG_IGN) 1346 ssh_signal(SIGQUIT, signal_handler); 1347 if (ssh_signal(SIGTERM, SIG_IGN) != SIG_IGN) 1348 ssh_signal(SIGTERM, signal_handler); 1349 ssh_signal(SIGWINCH, window_change_handler); 1350 1351 if (have_pty) 1352 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1353 1354 if (session_ident != -1) { 1355 if (escape_char_arg != SSH_ESCAPECHAR_NONE) { 1356 channel_register_filter(ssh, session_ident, 1357 client_simple_escape_filter, NULL, 1358 client_filter_cleanup, 1359 client_new_escape_filter_ctx( 1360 escape_char_arg)); 1361 } 1362 channel_register_cleanup(ssh, session_ident, 1363 client_channel_closed, 0); 1364 } 1365 1366 schedule_server_alive_check(); 1367 1368 /* Main loop of the client for the interactive session mode. */ 1369 while (!quit_pending) { 1370 1371 /* Process buffered packets sent by the server. */ 1372 client_process_buffered_input_packets(ssh); 1373 1374 if (session_closed && !channel_still_open(ssh)) 1375 break; 1376 1377 if (ssh_packet_is_rekeying(ssh)) { 1378 debug("rekeying in progress"); 1379 } else if (need_rekeying) { 1380 /* manual rekey request */ 1381 debug("need rekeying"); 1382 if ((r = kex_start_rekex(ssh)) != 0) 1383 fatal_fr(r, "kex_start_rekex"); 1384 need_rekeying = 0; 1385 } else { 1386 /* 1387 * Make packets from buffered channel data, and 1388 * enqueue them for sending to the server. 1389 */ 1390 if (ssh_packet_not_very_much_data_to_write(ssh)) 1391 channel_output_poll(ssh); 1392 1393 /* 1394 * Check if the window size has changed, and buffer a 1395 * message about it to the server if so. 1396 */ 1397 client_check_window_change(ssh); 1398 1399 if (quit_pending) 1400 break; 1401 } 1402 /* 1403 * Wait until we have something to do (something becomes 1404 * available on one of the descriptors). 1405 */ 1406 client_wait_until_can_do_something(ssh, &pfd, &npfd_alloc, 1407 &npfd_active, ssh_packet_is_rekeying(ssh), 1408 &conn_in_ready, &conn_out_ready); 1409 1410 if (quit_pending) 1411 break; 1412 1413 /* Do channel operations. */ 1414 channel_after_poll(ssh, pfd, npfd_active); 1415 1416 /* Buffer input from the connection. */ 1417 if (conn_in_ready) 1418 client_process_net_input(ssh); 1419 1420 if (quit_pending) 1421 break; 1422 1423 /* A timeout may have triggered rekeying */ 1424 if ((r = ssh_packet_check_rekey(ssh)) != 0) 1425 fatal_fr(r, "cannot start rekeying"); 1426 1427 /* 1428 * Send as much buffered packet data as possible to the 1429 * sender. 1430 */ 1431 if (conn_out_ready) { 1432 if ((r = ssh_packet_write_poll(ssh)) != 0) { 1433 sshpkt_fatal(ssh, r, 1434 "%s: ssh_packet_write_poll", __func__); 1435 } 1436 } 1437 1438 /* 1439 * If we are a backgrounded control master, and the 1440 * timeout has expired without any active client 1441 * connections, then quit. 1442 */ 1443 if (control_persist_exit_time > 0) { 1444 if (monotime() >= control_persist_exit_time) { 1445 debug("ControlPersist timeout expired"); 1446 break; 1447 } 1448 } 1449 } 1450 free(pfd); 1451 1452 /* Terminate the session. */ 1453 1454 /* Stop watching for window change. */ 1455 ssh_signal(SIGWINCH, SIG_DFL); 1456 1457 if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 || 1458 (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_BY_APPLICATION)) != 0 || 1459 (r = sshpkt_put_cstring(ssh, "disconnected by user")) != 0 || 1460 (r = sshpkt_put_cstring(ssh, "")) != 0 || /* language tag */ 1461 (r = sshpkt_send(ssh)) != 0 || 1462 (r = ssh_packet_write_wait(ssh)) != 0) 1463 fatal_fr(r, "send disconnect"); 1464 1465 channel_free_all(ssh); 1466 1467 if (have_pty) 1468 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1469 1470 /* 1471 * If there was no shell or command requested, there will be no remote 1472 * exit status to be returned. In that case, clear error code if the 1473 * connection was deliberately terminated at this end. 1474 */ 1475 if (options.session_type == SESSION_TYPE_NONE && 1476 received_signal == SIGTERM) { 1477 received_signal = 0; 1478 exit_status = 0; 1479 } 1480 1481 if (received_signal) { 1482 verbose("Killed by signal %d.", (int) received_signal); 1483 cleanup_exit(255); 1484 } 1485 1486 /* 1487 * In interactive mode (with pseudo tty) display a message indicating 1488 * that the connection has been closed. 1489 */ 1490 if (have_pty && options.log_level >= SYSLOG_LEVEL_INFO) 1491 quit_message("Connection to %s closed.", host); 1492 1493 /* Output any buffered data for stderr. */ 1494 if (sshbuf_len(stderr_buffer) > 0) { 1495 len = atomicio(vwrite, fileno(stderr), 1496 (u_char *)sshbuf_ptr(stderr_buffer), 1497 sshbuf_len(stderr_buffer)); 1498 if (len < 0 || (u_int)len != sshbuf_len(stderr_buffer)) 1499 error("Write failed flushing stderr buffer."); 1500 else if ((r = sshbuf_consume(stderr_buffer, len)) != 0) 1501 fatal_fr(r, "sshbuf_consume"); 1502 } 1503 1504 /* Clear and free any buffers. */ 1505 sshbuf_free(stderr_buffer); 1506 1507 /* Report bytes transferred, and transfer rates. */ 1508 total_time = monotime_double() - start_time; 1509 ssh_packet_get_bytes(ssh, &ibytes, &obytes); 1510 verbose("Transferred: sent %llu, received %llu bytes, in %.1f seconds", 1511 (unsigned long long)obytes, (unsigned long long)ibytes, total_time); 1512 if (total_time > 0) 1513 verbose("Bytes per second: sent %.1f, received %.1f", 1514 obytes / total_time, ibytes / total_time); 1515 /* Return the exit status of the program. */ 1516 debug("Exit status %d", exit_status); 1517 return exit_status; 1518 } 1519 1520 /*********/ 1521 1522 static Channel * 1523 client_request_forwarded_tcpip(struct ssh *ssh, const char *request_type, 1524 int rchan, u_int rwindow, u_int rmaxpack) 1525 { 1526 Channel *c = NULL; 1527 struct sshbuf *b = NULL; 1528 char *listen_address, *originator_address; 1529 u_int listen_port, originator_port; 1530 int r; 1531 1532 /* Get rest of the packet */ 1533 if ((r = sshpkt_get_cstring(ssh, &listen_address, NULL)) != 0 || 1534 (r = sshpkt_get_u32(ssh, &listen_port)) != 0 || 1535 (r = sshpkt_get_cstring(ssh, &originator_address, NULL)) != 0 || 1536 (r = sshpkt_get_u32(ssh, &originator_port)) != 0 || 1537 (r = sshpkt_get_end(ssh)) != 0) 1538 fatal_fr(r, "parse packet"); 1539 1540 debug_f("listen %s port %d, originator %s port %d", 1541 listen_address, listen_port, originator_address, originator_port); 1542 1543 if (listen_port > 0xffff) 1544 error_f("invalid listen port"); 1545 else if (originator_port > 0xffff) 1546 error_f("invalid originator port"); 1547 else { 1548 c = channel_connect_by_listen_address(ssh, 1549 listen_address, listen_port, "forwarded-tcpip", 1550 originator_address); 1551 } 1552 1553 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) { 1554 if ((b = sshbuf_new()) == NULL) { 1555 error_f("alloc reply"); 1556 goto out; 1557 } 1558 /* reconstruct and send to muxclient */ 1559 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 1560 (r = sshbuf_put_u8(b, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1561 (r = sshbuf_put_cstring(b, request_type)) != 0 || 1562 (r = sshbuf_put_u32(b, rchan)) != 0 || 1563 (r = sshbuf_put_u32(b, rwindow)) != 0 || 1564 (r = sshbuf_put_u32(b, rmaxpack)) != 0 || 1565 (r = sshbuf_put_cstring(b, listen_address)) != 0 || 1566 (r = sshbuf_put_u32(b, listen_port)) != 0 || 1567 (r = sshbuf_put_cstring(b, originator_address)) != 0 || 1568 (r = sshbuf_put_u32(b, originator_port)) != 0 || 1569 (r = sshbuf_put_stringb(c->output, b)) != 0) { 1570 error_fr(r, "compose for muxclient"); 1571 goto out; 1572 } 1573 } 1574 1575 out: 1576 sshbuf_free(b); 1577 free(originator_address); 1578 free(listen_address); 1579 return c; 1580 } 1581 1582 static Channel * 1583 client_request_forwarded_streamlocal(struct ssh *ssh, 1584 const char *request_type, int rchan) 1585 { 1586 Channel *c = NULL; 1587 char *listen_path; 1588 int r; 1589 1590 /* Get the remote path. */ 1591 if ((r = sshpkt_get_cstring(ssh, &listen_path, NULL)) != 0 || 1592 (r = sshpkt_get_string(ssh, NULL, NULL)) != 0 || /* reserved */ 1593 (r = sshpkt_get_end(ssh)) != 0) 1594 fatal_fr(r, "parse packet"); 1595 1596 debug_f("request: %s", listen_path); 1597 1598 c = channel_connect_by_listen_path(ssh, listen_path, 1599 "forwarded-streamlocal@openssh.com", "forwarded-streamlocal"); 1600 free(listen_path); 1601 return c; 1602 } 1603 1604 static Channel * 1605 client_request_x11(struct ssh *ssh, const char *request_type, int rchan) 1606 { 1607 Channel *c = NULL; 1608 char *originator; 1609 u_int originator_port; 1610 int r, sock; 1611 1612 if (!options.forward_x11) { 1613 error("Warning: ssh server tried X11 forwarding."); 1614 error("Warning: this is probably a break-in attempt by a " 1615 "malicious server."); 1616 return NULL; 1617 } 1618 if (x11_refuse_time != 0 && monotime() >= x11_refuse_time) { 1619 verbose("Rejected X11 connection after ForwardX11Timeout " 1620 "expired"); 1621 return NULL; 1622 } 1623 if ((r = sshpkt_get_cstring(ssh, &originator, NULL)) != 0 || 1624 (r = sshpkt_get_u32(ssh, &originator_port)) != 0 || 1625 (r = sshpkt_get_end(ssh)) != 0) 1626 fatal_fr(r, "parse packet"); 1627 /* XXX check permission */ 1628 /* XXX range check originator port? */ 1629 debug("client_request_x11: request from %s %u", originator, 1630 originator_port); 1631 free(originator); 1632 sock = x11_connect_display(ssh); 1633 if (sock < 0) 1634 return NULL; 1635 c = channel_new(ssh, "x11", 1636 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1637 CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); 1638 c->force_drain = 1; 1639 return c; 1640 } 1641 1642 static Channel * 1643 client_request_agent(struct ssh *ssh, const char *request_type, int rchan) 1644 { 1645 Channel *c = NULL; 1646 int r, sock; 1647 1648 if (!options.forward_agent) { 1649 error("Warning: ssh server tried agent forwarding."); 1650 error("Warning: this is probably a break-in attempt by a " 1651 "malicious server."); 1652 return NULL; 1653 } 1654 if (forward_agent_sock_path == NULL) { 1655 r = ssh_get_authentication_socket(&sock); 1656 } else { 1657 r = ssh_get_authentication_socket_path(forward_agent_sock_path, &sock); 1658 } 1659 if (r != 0) { 1660 if (r != SSH_ERR_AGENT_NOT_PRESENT) 1661 debug_fr(r, "ssh_get_authentication_socket"); 1662 return NULL; 1663 } 1664 if ((r = ssh_agent_bind_hostkey(sock, ssh->kex->initial_hostkey, 1665 ssh->kex->session_id, ssh->kex->initial_sig, 1)) == 0) 1666 debug_f("bound agent to hostkey"); 1667 else 1668 debug2_fr(r, "ssh_agent_bind_hostkey"); 1669 1670 c = channel_new(ssh, "authentication agent connection", 1671 SSH_CHANNEL_OPEN, sock, sock, -1, 1672 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, 1673 "authentication agent connection", 1); 1674 c->force_drain = 1; 1675 return c; 1676 } 1677 1678 char * 1679 client_request_tun_fwd(struct ssh *ssh, int tun_mode, 1680 int local_tun, int remote_tun, channel_open_fn *cb, void *cbctx) 1681 { 1682 Channel *c; 1683 int r, fd; 1684 char *ifname = NULL; 1685 1686 if (tun_mode == SSH_TUNMODE_NO) 1687 return 0; 1688 1689 debug("Requesting tun unit %d in mode %d", local_tun, tun_mode); 1690 1691 /* Open local tunnel device */ 1692 if ((fd = tun_open(local_tun, tun_mode, &ifname)) == -1) { 1693 error("Tunnel device open failed."); 1694 return NULL; 1695 } 1696 debug("Tunnel forwarding using interface %s", ifname); 1697 1698 c = channel_new(ssh, "tun", SSH_CHANNEL_OPENING, fd, fd, -1, 1699 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1); 1700 c->datagram = 1; 1701 1702 #if defined(SSH_TUN_FILTER) 1703 if (options.tun_open == SSH_TUNMODE_POINTOPOINT) 1704 channel_register_filter(ssh, c->self, sys_tun_infilter, 1705 sys_tun_outfilter, NULL, NULL); 1706 #endif 1707 1708 if (cb != NULL) 1709 channel_register_open_confirm(ssh, c->self, cb, cbctx); 1710 1711 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1712 (r = sshpkt_put_cstring(ssh, "tun@openssh.com")) != 0 || 1713 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1714 (r = sshpkt_put_u32(ssh, c->local_window_max)) != 0 || 1715 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 1716 (r = sshpkt_put_u32(ssh, tun_mode)) != 0 || 1717 (r = sshpkt_put_u32(ssh, remote_tun)) != 0 || 1718 (r = sshpkt_send(ssh)) != 0) 1719 sshpkt_fatal(ssh, r, "%s: send reply", __func__); 1720 1721 return ifname; 1722 } 1723 1724 /* XXXX move to generic input handler */ 1725 static int 1726 client_input_channel_open(int type, u_int32_t seq, struct ssh *ssh) 1727 { 1728 Channel *c = NULL; 1729 char *ctype = NULL; 1730 int r; 1731 u_int rchan; 1732 size_t len; 1733 u_int rmaxpack, rwindow; 1734 1735 if ((r = sshpkt_get_cstring(ssh, &ctype, &len)) != 0 || 1736 (r = sshpkt_get_u32(ssh, &rchan)) != 0 || 1737 (r = sshpkt_get_u32(ssh, &rwindow)) != 0 || 1738 (r = sshpkt_get_u32(ssh, &rmaxpack)) != 0) 1739 goto out; 1740 1741 debug("client_input_channel_open: ctype %s rchan %d win %d max %d", 1742 ctype, rchan, rwindow, rmaxpack); 1743 1744 if (strcmp(ctype, "forwarded-tcpip") == 0) { 1745 c = client_request_forwarded_tcpip(ssh, ctype, rchan, rwindow, 1746 rmaxpack); 1747 } else if (strcmp(ctype, "forwarded-streamlocal@openssh.com") == 0) { 1748 c = client_request_forwarded_streamlocal(ssh, ctype, rchan); 1749 } else if (strcmp(ctype, "x11") == 0) { 1750 c = client_request_x11(ssh, ctype, rchan); 1751 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) { 1752 c = client_request_agent(ssh, ctype, rchan); 1753 } 1754 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) { 1755 debug3("proxied to downstream: %s", ctype); 1756 } else if (c != NULL) { 1757 debug("confirm %s", ctype); 1758 c->remote_id = rchan; 1759 c->have_remote_id = 1; 1760 c->remote_window = rwindow; 1761 c->remote_maxpacket = rmaxpack; 1762 if (c->type != SSH_CHANNEL_CONNECTING) { 1763 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 1764 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1765 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1766 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1767 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 1768 (r = sshpkt_send(ssh)) != 0) 1769 sshpkt_fatal(ssh, r, "%s: send reply", __func__); 1770 } 1771 } else { 1772 debug("failure %s", ctype); 1773 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || 1774 (r = sshpkt_put_u32(ssh, rchan)) != 0 || 1775 (r = sshpkt_put_u32(ssh, SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED)) != 0 || 1776 (r = sshpkt_put_cstring(ssh, "open failed")) != 0 || 1777 (r = sshpkt_put_cstring(ssh, "")) != 0 || 1778 (r = sshpkt_send(ssh)) != 0) 1779 sshpkt_fatal(ssh, r, "%s: send failure", __func__); 1780 } 1781 r = 0; 1782 out: 1783 free(ctype); 1784 return r; 1785 } 1786 1787 static int 1788 client_input_channel_req(int type, u_int32_t seq, struct ssh *ssh) 1789 { 1790 Channel *c = NULL; 1791 char *rtype = NULL; 1792 u_char reply; 1793 u_int id, exitval; 1794 int r, success = 0; 1795 1796 if ((r = sshpkt_get_u32(ssh, &id)) != 0) 1797 return r; 1798 if (id <= INT_MAX) 1799 c = channel_lookup(ssh, id); 1800 if (channel_proxy_upstream(c, type, seq, ssh)) 1801 return 0; 1802 if ((r = sshpkt_get_cstring(ssh, &rtype, NULL)) != 0 || 1803 (r = sshpkt_get_u8(ssh, &reply)) != 0) 1804 goto out; 1805 1806 debug("client_input_channel_req: channel %u rtype %s reply %d", 1807 id, rtype, reply); 1808 1809 if (c == NULL) { 1810 error("client_input_channel_req: channel %d: " 1811 "unknown channel", id); 1812 } else if (strcmp(rtype, "eow@openssh.com") == 0) { 1813 if ((r = sshpkt_get_end(ssh)) != 0) 1814 goto out; 1815 chan_rcvd_eow(ssh, c); 1816 } else if (strcmp(rtype, "exit-status") == 0) { 1817 if ((r = sshpkt_get_u32(ssh, &exitval)) != 0) 1818 goto out; 1819 if (c->ctl_chan != -1) { 1820 mux_exit_message(ssh, c, exitval); 1821 success = 1; 1822 } else if ((int)id == session_ident) { 1823 /* Record exit value of local session */ 1824 success = 1; 1825 exit_status = exitval; 1826 } else { 1827 /* Probably for a mux channel that has already closed */ 1828 debug_f("no sink for exit-status on channel %d", 1829 id); 1830 } 1831 if ((r = sshpkt_get_end(ssh)) != 0) 1832 goto out; 1833 } 1834 if (reply && c != NULL && !(c->flags & CHAN_CLOSE_SENT)) { 1835 if (!c->have_remote_id) 1836 fatal_f("channel %d: no remote_id", c->self); 1837 if ((r = sshpkt_start(ssh, success ? 1838 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE)) != 0 || 1839 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1840 (r = sshpkt_send(ssh)) != 0) 1841 sshpkt_fatal(ssh, r, "%s: send failure", __func__); 1842 } 1843 r = 0; 1844 out: 1845 free(rtype); 1846 return r; 1847 } 1848 1849 struct hostkeys_update_ctx { 1850 /* The hostname and (optionally) IP address string for the server */ 1851 char *host_str, *ip_str; 1852 1853 /* 1854 * Keys received from the server and a flag for each indicating 1855 * whether they already exist in known_hosts. 1856 * keys_match is filled in by hostkeys_find() and later (for new 1857 * keys) by client_global_hostkeys_prove_confirm(). 1858 */ 1859 struct sshkey **keys; 1860 u_int *keys_match; /* mask of HKF_MATCH_* from hostfile.h */ 1861 int *keys_verified; /* flag for new keys verified by server */ 1862 size_t nkeys, nnew, nincomplete; /* total, new keys, incomplete match */ 1863 1864 /* 1865 * Keys that are in known_hosts, but were not present in the update 1866 * from the server (i.e. scheduled to be deleted). 1867 * Filled in by hostkeys_find(). 1868 */ 1869 struct sshkey **old_keys; 1870 size_t nold; 1871 1872 /* Various special cases. */ 1873 int complex_hostspec; /* wildcard or manual pattern-list host name */ 1874 int ca_available; /* saw CA key for this host */ 1875 int old_key_seen; /* saw old key with other name/addr */ 1876 int other_name_seen; /* saw key with other name/addr */ 1877 }; 1878 1879 static void 1880 hostkeys_update_ctx_free(struct hostkeys_update_ctx *ctx) 1881 { 1882 size_t i; 1883 1884 if (ctx == NULL) 1885 return; 1886 for (i = 0; i < ctx->nkeys; i++) 1887 sshkey_free(ctx->keys[i]); 1888 free(ctx->keys); 1889 free(ctx->keys_match); 1890 free(ctx->keys_verified); 1891 for (i = 0; i < ctx->nold; i++) 1892 sshkey_free(ctx->old_keys[i]); 1893 free(ctx->old_keys); 1894 free(ctx->host_str); 1895 free(ctx->ip_str); 1896 free(ctx); 1897 } 1898 1899 /* 1900 * Returns non-zero if a known_hosts hostname list is not of a form that 1901 * can be handled by UpdateHostkeys. These include wildcard hostnames and 1902 * hostnames lists that do not follow the form host[,ip]. 1903 */ 1904 static int 1905 hostspec_is_complex(const char *hosts) 1906 { 1907 char *cp; 1908 1909 /* wildcard */ 1910 if (strchr(hosts, '*') != NULL || strchr(hosts, '?') != NULL) 1911 return 1; 1912 /* single host/ip = ok */ 1913 if ((cp = strchr(hosts, ',')) == NULL) 1914 return 0; 1915 /* more than two entries on the line */ 1916 if (strchr(cp + 1, ',') != NULL) 1917 return 1; 1918 /* XXX maybe parse cp+1 and ensure it is an IP? */ 1919 return 0; 1920 } 1921 1922 /* callback to search for ctx->keys in known_hosts */ 1923 static int 1924 hostkeys_find(struct hostkey_foreach_line *l, void *_ctx) 1925 { 1926 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 1927 size_t i; 1928 struct sshkey **tmp; 1929 1930 if (l->key == NULL) 1931 return 0; 1932 if (l->status != HKF_STATUS_MATCHED) { 1933 /* Record if one of the keys appears on a non-matching line */ 1934 for (i = 0; i < ctx->nkeys; i++) { 1935 if (sshkey_equal(l->key, ctx->keys[i])) { 1936 ctx->other_name_seen = 1; 1937 debug3_f("found %s key under different " 1938 "name/addr at %s:%ld", 1939 sshkey_ssh_name(ctx->keys[i]), 1940 l->path, l->linenum); 1941 return 0; 1942 } 1943 } 1944 return 0; 1945 } 1946 /* Don't proceed if revocation or CA markers are present */ 1947 /* XXX relax this */ 1948 if (l->marker != MRK_NONE) { 1949 debug3_f("hostkeys file %s:%ld has CA/revocation marker", 1950 l->path, l->linenum); 1951 ctx->complex_hostspec = 1; 1952 return 0; 1953 } 1954 1955 /* If CheckHostIP is enabled, then check for mismatched hostname/addr */ 1956 if (ctx->ip_str != NULL && strchr(l->hosts, ',') != NULL) { 1957 if ((l->match & HKF_MATCH_HOST) == 0) { 1958 /* Record if address matched a different hostname. */ 1959 ctx->other_name_seen = 1; 1960 debug3_f("found address %s against different hostname " 1961 "at %s:%ld", ctx->ip_str, l->path, l->linenum); 1962 return 0; 1963 } else if ((l->match & HKF_MATCH_IP) == 0) { 1964 /* Record if hostname matched a different address. */ 1965 ctx->other_name_seen = 1; 1966 debug3_f("found hostname %s against different address " 1967 "at %s:%ld", ctx->host_str, l->path, l->linenum); 1968 } 1969 } 1970 1971 /* 1972 * UpdateHostkeys is skipped for wildcard host names and hostnames 1973 * that contain more than two entries (ssh never writes these). 1974 */ 1975 if (hostspec_is_complex(l->hosts)) { 1976 debug3_f("hostkeys file %s:%ld complex host specification", 1977 l->path, l->linenum); 1978 ctx->complex_hostspec = 1; 1979 return 0; 1980 } 1981 1982 /* Mark off keys we've already seen for this host */ 1983 for (i = 0; i < ctx->nkeys; i++) { 1984 if (!sshkey_equal(l->key, ctx->keys[i])) 1985 continue; 1986 debug3_f("found %s key at %s:%ld", 1987 sshkey_ssh_name(ctx->keys[i]), l->path, l->linenum); 1988 ctx->keys_match[i] |= l->match; 1989 return 0; 1990 } 1991 /* This line contained a key that not offered by the server */ 1992 debug3_f("deprecated %s key at %s:%ld", sshkey_ssh_name(l->key), 1993 l->path, l->linenum); 1994 if ((tmp = recallocarray(ctx->old_keys, ctx->nold, ctx->nold + 1, 1995 sizeof(*ctx->old_keys))) == NULL) 1996 fatal_f("recallocarray failed nold = %zu", ctx->nold); 1997 ctx->old_keys = tmp; 1998 ctx->old_keys[ctx->nold++] = l->key; 1999 l->key = NULL; 2000 2001 return 0; 2002 } 2003 2004 /* callback to search for ctx->old_keys in known_hosts under other names */ 2005 static int 2006 hostkeys_check_old(struct hostkey_foreach_line *l, void *_ctx) 2007 { 2008 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 2009 size_t i; 2010 int hashed; 2011 2012 /* only care about lines that *don't* match the active host spec */ 2013 if (l->status == HKF_STATUS_MATCHED || l->key == NULL) 2014 return 0; 2015 2016 hashed = l->match & (HKF_MATCH_HOST_HASHED|HKF_MATCH_IP_HASHED); 2017 for (i = 0; i < ctx->nold; i++) { 2018 if (!sshkey_equal(l->key, ctx->old_keys[i])) 2019 continue; 2020 debug3_f("found deprecated %s key at %s:%ld as %s", 2021 sshkey_ssh_name(ctx->old_keys[i]), l->path, l->linenum, 2022 hashed ? "[HASHED]" : l->hosts); 2023 ctx->old_key_seen = 1; 2024 break; 2025 } 2026 return 0; 2027 } 2028 2029 /* 2030 * Check known_hosts files for deprecated keys under other names. Returns 0 2031 * on success or -1 on failure. Updates ctx->old_key_seen if deprecated keys 2032 * exist under names other than the active hostname/IP. 2033 */ 2034 static int 2035 check_old_keys_othernames(struct hostkeys_update_ctx *ctx) 2036 { 2037 size_t i; 2038 int r; 2039 2040 debug2_f("checking for %zu deprecated keys", ctx->nold); 2041 for (i = 0; i < options.num_user_hostfiles; i++) { 2042 debug3_f("searching %s for %s / %s", 2043 options.user_hostfiles[i], ctx->host_str, 2044 ctx->ip_str ? ctx->ip_str : "(none)"); 2045 if ((r = hostkeys_foreach(options.user_hostfiles[i], 2046 hostkeys_check_old, ctx, ctx->host_str, ctx->ip_str, 2047 HKF_WANT_PARSE_KEY, 0)) != 0) { 2048 if (r == SSH_ERR_SYSTEM_ERROR && errno == ENOENT) { 2049 debug_f("hostkeys file %s does not exist", 2050 options.user_hostfiles[i]); 2051 continue; 2052 } 2053 error_fr(r, "hostkeys_foreach failed for %s", 2054 options.user_hostfiles[i]); 2055 return -1; 2056 } 2057 } 2058 return 0; 2059 } 2060 2061 static void 2062 hostkey_change_preamble(LogLevel loglevel) 2063 { 2064 do_log2(loglevel, "The server has updated its host keys."); 2065 do_log2(loglevel, "These changes were verified by the server's " 2066 "existing trusted key."); 2067 } 2068 2069 static void 2070 update_known_hosts(struct hostkeys_update_ctx *ctx) 2071 { 2072 int r, was_raw = 0, first = 1; 2073 int asking = options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK; 2074 LogLevel loglevel = asking ? SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_VERBOSE; 2075 char *fp, *response; 2076 size_t i; 2077 struct stat sb; 2078 2079 for (i = 0; i < ctx->nkeys; i++) { 2080 if (!ctx->keys_verified[i]) 2081 continue; 2082 if ((fp = sshkey_fingerprint(ctx->keys[i], 2083 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 2084 fatal_f("sshkey_fingerprint failed"); 2085 if (first && asking) 2086 hostkey_change_preamble(loglevel); 2087 do_log2(loglevel, "Learned new hostkey: %s %s", 2088 sshkey_type(ctx->keys[i]), fp); 2089 first = 0; 2090 free(fp); 2091 } 2092 for (i = 0; i < ctx->nold; i++) { 2093 if ((fp = sshkey_fingerprint(ctx->old_keys[i], 2094 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 2095 fatal_f("sshkey_fingerprint failed"); 2096 if (first && asking) 2097 hostkey_change_preamble(loglevel); 2098 do_log2(loglevel, "Deprecating obsolete hostkey: %s %s", 2099 sshkey_type(ctx->old_keys[i]), fp); 2100 first = 0; 2101 free(fp); 2102 } 2103 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) { 2104 if (get_saved_tio() != NULL) { 2105 leave_raw_mode(1); 2106 was_raw = 1; 2107 } 2108 response = NULL; 2109 for (i = 0; !quit_pending && i < 3; i++) { 2110 free(response); 2111 response = read_passphrase("Accept updated hostkeys? " 2112 "(yes/no): ", RP_ECHO); 2113 if (response != NULL && strcasecmp(response, "yes") == 0) 2114 break; 2115 else if (quit_pending || response == NULL || 2116 strcasecmp(response, "no") == 0) { 2117 options.update_hostkeys = 0; 2118 break; 2119 } else { 2120 do_log2(loglevel, "Please enter " 2121 "\"yes\" or \"no\""); 2122 } 2123 } 2124 if (quit_pending || i >= 3 || response == NULL) 2125 options.update_hostkeys = 0; 2126 free(response); 2127 if (was_raw) 2128 enter_raw_mode(1); 2129 } 2130 if (options.update_hostkeys == 0) 2131 return; 2132 /* 2133 * Now that all the keys are verified, we can go ahead and replace 2134 * them in known_hosts (assuming SSH_UPDATE_HOSTKEYS_ASK didn't 2135 * cancel the operation). 2136 */ 2137 for (i = 0; i < options.num_user_hostfiles; i++) { 2138 /* 2139 * NB. keys are only added to hostfiles[0], for the rest we 2140 * just delete the hostname entries. 2141 */ 2142 if (stat(options.user_hostfiles[i], &sb) != 0) { 2143 if (errno == ENOENT) { 2144 debug_f("known hosts file %s does not " 2145 "exist", options.user_hostfiles[i]); 2146 } else { 2147 error_f("known hosts file %s " 2148 "inaccessible: %s", 2149 options.user_hostfiles[i], strerror(errno)); 2150 } 2151 continue; 2152 } 2153 if ((r = hostfile_replace_entries(options.user_hostfiles[i], 2154 ctx->host_str, ctx->ip_str, 2155 i == 0 ? ctx->keys : NULL, i == 0 ? ctx->nkeys : 0, 2156 options.hash_known_hosts, 0, 2157 options.fingerprint_hash)) != 0) { 2158 error_fr(r, "hostfile_replace_entries failed for %s", 2159 options.user_hostfiles[i]); 2160 } 2161 } 2162 } 2163 2164 static void 2165 client_global_hostkeys_prove_confirm(struct ssh *ssh, int type, 2166 u_int32_t seq, void *_ctx) 2167 { 2168 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 2169 size_t i, ndone; 2170 struct sshbuf *signdata; 2171 int r, plaintype; 2172 const u_char *sig; 2173 const char *rsa_kexalg = NULL; 2174 char *alg = NULL; 2175 size_t siglen; 2176 2177 if (ctx->nnew == 0) 2178 fatal_f("ctx->nnew == 0"); /* sanity */ 2179 if (type != SSH2_MSG_REQUEST_SUCCESS) { 2180 error("Server failed to confirm ownership of " 2181 "private host keys"); 2182 hostkeys_update_ctx_free(ctx); 2183 return; 2184 } 2185 if (sshkey_type_plain(sshkey_type_from_name( 2186 ssh->kex->hostkey_alg)) == KEY_RSA) 2187 rsa_kexalg = ssh->kex->hostkey_alg; 2188 if ((signdata = sshbuf_new()) == NULL) 2189 fatal_f("sshbuf_new failed"); 2190 /* 2191 * Expect a signature for each of the ctx->nnew private keys we 2192 * haven't seen before. They will be in the same order as the 2193 * ctx->keys where the corresponding ctx->keys_match[i] == 0. 2194 */ 2195 for (ndone = i = 0; i < ctx->nkeys; i++) { 2196 if (ctx->keys_match[i]) 2197 continue; 2198 plaintype = sshkey_type_plain(ctx->keys[i]->type); 2199 /* Prepare data to be signed: session ID, unique string, key */ 2200 sshbuf_reset(signdata); 2201 if ( (r = sshbuf_put_cstring(signdata, 2202 "hostkeys-prove-00@openssh.com")) != 0 || 2203 (r = sshbuf_put_stringb(signdata, 2204 ssh->kex->session_id)) != 0 || 2205 (r = sshkey_puts(ctx->keys[i], signdata)) != 0) 2206 fatal_fr(r, "compose signdata"); 2207 /* Extract and verify signature */ 2208 if ((r = sshpkt_get_string_direct(ssh, &sig, &siglen)) != 0) { 2209 error_fr(r, "parse sig"); 2210 goto out; 2211 } 2212 if ((r = sshkey_get_sigtype(sig, siglen, &alg)) != 0) { 2213 error_fr(r, "server gave unintelligible signature " 2214 "for %s key %zu", sshkey_type(ctx->keys[i]), i); 2215 goto out; 2216 } 2217 /* 2218 * Special case for RSA keys: if a RSA hostkey was negotiated, 2219 * then use its signature type for verification of RSA hostkey 2220 * proofs. Otherwise, accept only RSA-SHA256/512 signatures. 2221 */ 2222 if (plaintype == KEY_RSA && rsa_kexalg == NULL && 2223 match_pattern_list(alg, HOSTKEY_PROOF_RSA_ALGS, 0) != 1) { 2224 debug_f("server used untrusted RSA signature algorithm " 2225 "%s for key %zu, disregarding", alg, i); 2226 free(alg); 2227 /* zap the key from the list */ 2228 sshkey_free(ctx->keys[i]); 2229 ctx->keys[i] = NULL; 2230 ndone++; 2231 continue; 2232 } 2233 debug3_f("verify %s key %zu using sigalg %s", 2234 sshkey_type(ctx->keys[i]), i, alg); 2235 free(alg); 2236 if ((r = sshkey_verify(ctx->keys[i], sig, siglen, 2237 sshbuf_ptr(signdata), sshbuf_len(signdata), 2238 plaintype == KEY_RSA ? rsa_kexalg : NULL, 0, NULL)) != 0) { 2239 error_fr(r, "server gave bad signature for %s key %zu", 2240 sshkey_type(ctx->keys[i]), i); 2241 goto out; 2242 } 2243 /* Key is good. Mark it as 'seen' */ 2244 ctx->keys_verified[i] = 1; 2245 ndone++; 2246 } 2247 /* Shouldn't happen */ 2248 if (ndone != ctx->nnew) 2249 fatal_f("ndone != ctx->nnew (%zu / %zu)", ndone, ctx->nnew); 2250 if ((r = sshpkt_get_end(ssh)) != 0) { 2251 error_f("protocol error"); 2252 goto out; 2253 } 2254 2255 /* Make the edits to known_hosts */ 2256 update_known_hosts(ctx); 2257 out: 2258 hostkeys_update_ctx_free(ctx); 2259 hostkeys_update_complete = 1; 2260 client_repledge(); 2261 } 2262 2263 /* 2264 * Returns non-zero if the key is accepted by HostkeyAlgorithms. 2265 * Made slightly less trivial by the multiple RSA signature algorithm names. 2266 */ 2267 static int 2268 key_accepted_by_hostkeyalgs(const struct sshkey *key) 2269 { 2270 const char *ktype = sshkey_ssh_name(key); 2271 const char *hostkeyalgs = options.hostkeyalgorithms; 2272 2273 if (key == NULL || key->type == KEY_UNSPEC) 2274 return 0; 2275 if (key->type == KEY_RSA && 2276 (match_pattern_list("rsa-sha2-256", hostkeyalgs, 0) == 1 || 2277 match_pattern_list("rsa-sha2-512", hostkeyalgs, 0) == 1)) 2278 return 1; 2279 return match_pattern_list(ktype, hostkeyalgs, 0) == 1; 2280 } 2281 2282 /* 2283 * Handle hostkeys-00@openssh.com global request to inform the client of all 2284 * the server's hostkeys. The keys are checked against the user's 2285 * HostkeyAlgorithms preference before they are accepted. 2286 */ 2287 static int 2288 client_input_hostkeys(struct ssh *ssh) 2289 { 2290 const u_char *blob = NULL; 2291 size_t i, len = 0; 2292 struct sshbuf *buf = NULL; 2293 struct sshkey *key = NULL, **tmp; 2294 int r, prove_sent = 0; 2295 char *fp; 2296 static int hostkeys_seen = 0; /* XXX use struct ssh */ 2297 extern struct sockaddr_storage hostaddr; /* XXX from ssh.c */ 2298 struct hostkeys_update_ctx *ctx = NULL; 2299 u_int want; 2300 2301 if (hostkeys_seen) 2302 fatal_f("server already sent hostkeys"); 2303 if (!can_update_hostkeys()) 2304 return 1; 2305 hostkeys_seen = 1; 2306 2307 ctx = xcalloc(1, sizeof(*ctx)); 2308 while (ssh_packet_remaining(ssh) > 0) { 2309 sshkey_free(key); 2310 key = NULL; 2311 if ((r = sshpkt_get_string_direct(ssh, &blob, &len)) != 0) { 2312 error_fr(r, "parse key"); 2313 goto out; 2314 } 2315 if ((r = sshkey_from_blob(blob, len, &key)) != 0) { 2316 do_log2_fr(r, r == SSH_ERR_KEY_TYPE_UNKNOWN ? 2317 SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_ERROR, 2318 "convert key"); 2319 continue; 2320 } 2321 fp = sshkey_fingerprint(key, options.fingerprint_hash, 2322 SSH_FP_DEFAULT); 2323 debug3_f("received %s key %s", sshkey_type(key), fp); 2324 free(fp); 2325 2326 if (!key_accepted_by_hostkeyalgs(key)) { 2327 debug3_f("%s key not permitted by " 2328 "HostkeyAlgorithms", sshkey_ssh_name(key)); 2329 continue; 2330 } 2331 /* Skip certs */ 2332 if (sshkey_is_cert(key)) { 2333 debug3_f("%s key is a certificate; skipping", 2334 sshkey_ssh_name(key)); 2335 continue; 2336 } 2337 /* Ensure keys are unique */ 2338 for (i = 0; i < ctx->nkeys; i++) { 2339 if (sshkey_equal(key, ctx->keys[i])) { 2340 error_f("received duplicated %s host key", 2341 sshkey_ssh_name(key)); 2342 goto out; 2343 } 2344 } 2345 /* Key is good, record it */ 2346 if ((tmp = recallocarray(ctx->keys, ctx->nkeys, ctx->nkeys + 1, 2347 sizeof(*ctx->keys))) == NULL) 2348 fatal_f("recallocarray failed nkeys = %zu", 2349 ctx->nkeys); 2350 ctx->keys = tmp; 2351 ctx->keys[ctx->nkeys++] = key; 2352 key = NULL; 2353 } 2354 2355 if (ctx->nkeys == 0) { 2356 debug_f("server sent no hostkeys"); 2357 goto out; 2358 } 2359 2360 if ((ctx->keys_match = calloc(ctx->nkeys, 2361 sizeof(*ctx->keys_match))) == NULL || 2362 (ctx->keys_verified = calloc(ctx->nkeys, 2363 sizeof(*ctx->keys_verified))) == NULL) 2364 fatal_f("calloc failed"); 2365 2366 get_hostfile_hostname_ipaddr(host, 2367 options.check_host_ip ? (struct sockaddr *)&hostaddr : NULL, 2368 options.port, &ctx->host_str, 2369 options.check_host_ip ? &ctx->ip_str : NULL); 2370 2371 /* Find which keys we already know about. */ 2372 for (i = 0; i < options.num_user_hostfiles; i++) { 2373 debug_f("searching %s for %s / %s", 2374 options.user_hostfiles[i], ctx->host_str, 2375 ctx->ip_str ? ctx->ip_str : "(none)"); 2376 if ((r = hostkeys_foreach(options.user_hostfiles[i], 2377 hostkeys_find, ctx, ctx->host_str, ctx->ip_str, 2378 HKF_WANT_PARSE_KEY, 0)) != 0) { 2379 if (r == SSH_ERR_SYSTEM_ERROR && errno == ENOENT) { 2380 debug_f("hostkeys file %s does not exist", 2381 options.user_hostfiles[i]); 2382 continue; 2383 } 2384 error_fr(r, "hostkeys_foreach failed for %s", 2385 options.user_hostfiles[i]); 2386 goto out; 2387 } 2388 } 2389 2390 /* Figure out if we have any new keys to add */ 2391 ctx->nnew = ctx->nincomplete = 0; 2392 want = HKF_MATCH_HOST | ( options.check_host_ip ? HKF_MATCH_IP : 0); 2393 for (i = 0; i < ctx->nkeys; i++) { 2394 if (ctx->keys_match[i] == 0) 2395 ctx->nnew++; 2396 if ((ctx->keys_match[i] & want) != want) 2397 ctx->nincomplete++; 2398 } 2399 2400 debug3_f("%zu server keys: %zu new, %zu retained, " 2401 "%zu incomplete match. %zu to remove", ctx->nkeys, ctx->nnew, 2402 ctx->nkeys - ctx->nnew - ctx->nincomplete, 2403 ctx->nincomplete, ctx->nold); 2404 2405 if (ctx->nnew == 0 && ctx->nold == 0) { 2406 debug_f("no new or deprecated keys from server"); 2407 goto out; 2408 } 2409 2410 /* Various reasons why we cannot proceed with the update */ 2411 if (ctx->complex_hostspec) { 2412 debug_f("CA/revocation marker, manual host list or wildcard " 2413 "host pattern found, skipping UserKnownHostsFile update"); 2414 goto out; 2415 } 2416 if (ctx->other_name_seen) { 2417 debug_f("host key found matching a different name/address, " 2418 "skipping UserKnownHostsFile update"); 2419 goto out; 2420 } 2421 /* 2422 * If removing keys, check whether they appear under different 2423 * names/addresses and refuse to proceed if they do. This avoids 2424 * cases such as hosts with multiple names becoming inconsistent 2425 * with regards to CheckHostIP entries. 2426 * XXX UpdateHostkeys=force to override this (and other) checks? 2427 */ 2428 if (ctx->nold != 0) { 2429 if (check_old_keys_othernames(ctx) != 0) 2430 goto out; /* error already logged */ 2431 if (ctx->old_key_seen) { 2432 debug_f("key(s) for %s%s%s exist under other names; " 2433 "skipping UserKnownHostsFile update", 2434 ctx->host_str, ctx->ip_str == NULL ? "" : ",", 2435 ctx->ip_str == NULL ? "" : ctx->ip_str); 2436 goto out; 2437 } 2438 } 2439 2440 if (ctx->nnew == 0) { 2441 /* 2442 * We have some keys to remove or fix matching for. 2443 * We can proceed to do this without requiring a fresh proof 2444 * from the server. 2445 */ 2446 update_known_hosts(ctx); 2447 goto out; 2448 } 2449 /* 2450 * We have received previously-unseen keys from the server. 2451 * Ask the server to confirm ownership of the private halves. 2452 */ 2453 debug3_f("asking server to prove ownership for %zu keys", ctx->nnew); 2454 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 2455 (r = sshpkt_put_cstring(ssh, 2456 "hostkeys-prove-00@openssh.com")) != 0 || 2457 (r = sshpkt_put_u8(ssh, 1)) != 0) /* bool: want reply */ 2458 fatal_fr(r, "prepare hostkeys-prove"); 2459 if ((buf = sshbuf_new()) == NULL) 2460 fatal_f("sshbuf_new"); 2461 for (i = 0; i < ctx->nkeys; i++) { 2462 if (ctx->keys_match[i]) 2463 continue; 2464 sshbuf_reset(buf); 2465 if ((r = sshkey_putb(ctx->keys[i], buf)) != 0 || 2466 (r = sshpkt_put_stringb(ssh, buf)) != 0) 2467 fatal_fr(r, "assemble hostkeys-prove"); 2468 } 2469 if ((r = sshpkt_send(ssh)) != 0) 2470 fatal_fr(r, "send hostkeys-prove"); 2471 client_register_global_confirm( 2472 client_global_hostkeys_prove_confirm, ctx); 2473 ctx = NULL; /* will be freed in callback */ 2474 prove_sent = 1; 2475 2476 /* Success */ 2477 out: 2478 hostkeys_update_ctx_free(ctx); 2479 sshkey_free(key); 2480 sshbuf_free(buf); 2481 if (!prove_sent) { 2482 /* UpdateHostkeys handling completed */ 2483 hostkeys_update_complete = 1; 2484 client_repledge(); 2485 } 2486 /* 2487 * NB. Return success for all cases. The server doesn't need to know 2488 * what the client does with its hosts file. 2489 */ 2490 return 1; 2491 } 2492 2493 static int 2494 client_input_global_request(int type, u_int32_t seq, struct ssh *ssh) 2495 { 2496 char *rtype; 2497 u_char want_reply; 2498 int r, success = 0; 2499 2500 if ((r = sshpkt_get_cstring(ssh, &rtype, NULL)) != 0 || 2501 (r = sshpkt_get_u8(ssh, &want_reply)) != 0) 2502 goto out; 2503 debug("client_input_global_request: rtype %s want_reply %d", 2504 rtype, want_reply); 2505 if (strcmp(rtype, "hostkeys-00@openssh.com") == 0) 2506 success = client_input_hostkeys(ssh); 2507 if (want_reply) { 2508 if ((r = sshpkt_start(ssh, success ? SSH2_MSG_REQUEST_SUCCESS : 2509 SSH2_MSG_REQUEST_FAILURE)) != 0 || 2510 (r = sshpkt_send(ssh)) != 0 || 2511 (r = ssh_packet_write_wait(ssh)) != 0) 2512 goto out; 2513 } 2514 r = 0; 2515 out: 2516 free(rtype); 2517 return r; 2518 } 2519 2520 static void 2521 client_send_env(struct ssh *ssh, int id, const char *name, const char *val) 2522 { 2523 int r; 2524 2525 debug("channel %d: setting env %s = \"%s\"", id, name, val); 2526 channel_request_start(ssh, id, "env", 0); 2527 if ((r = sshpkt_put_cstring(ssh, name)) != 0 || 2528 (r = sshpkt_put_cstring(ssh, val)) != 0 || 2529 (r = sshpkt_send(ssh)) != 0) 2530 fatal_fr(r, "send setenv"); 2531 } 2532 2533 void 2534 client_session2_setup(struct ssh *ssh, int id, int want_tty, int want_subsystem, 2535 const char *term, struct termios *tiop, int in_fd, struct sshbuf *cmd, 2536 char **env) 2537 { 2538 size_t i, j, len; 2539 int matched, r; 2540 char *name, *val; 2541 Channel *c = NULL; 2542 2543 debug2_f("id %d", id); 2544 2545 if ((c = channel_lookup(ssh, id)) == NULL) 2546 fatal_f("channel %d: unknown channel", id); 2547 2548 ssh_packet_set_interactive(ssh, want_tty, 2549 options.ip_qos_interactive, options.ip_qos_bulk); 2550 2551 if (want_tty) { 2552 struct winsize ws; 2553 2554 /* Store window size in the packet. */ 2555 if (ioctl(in_fd, TIOCGWINSZ, &ws) == -1) 2556 memset(&ws, 0, sizeof(ws)); 2557 2558 channel_request_start(ssh, id, "pty-req", 1); 2559 client_expect_confirm(ssh, id, "PTY allocation", CONFIRM_TTY); 2560 if ((r = sshpkt_put_cstring(ssh, term != NULL ? term : "")) 2561 != 0 || 2562 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || 2563 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || 2564 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || 2565 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0) 2566 fatal_fr(r, "build pty-req"); 2567 if (tiop == NULL) 2568 tiop = get_saved_tio(); 2569 ssh_tty_make_modes(ssh, -1, tiop); 2570 if ((r = sshpkt_send(ssh)) != 0) 2571 fatal_fr(r, "send pty-req"); 2572 /* XXX wait for reply */ 2573 c->client_tty = 1; 2574 } 2575 2576 /* Transfer any environment variables from client to server */ 2577 if (options.num_send_env != 0 && env != NULL) { 2578 debug("Sending environment."); 2579 for (i = 0; env[i] != NULL; i++) { 2580 /* Split */ 2581 name = xstrdup(env[i]); 2582 if ((val = strchr(name, '=')) == NULL) { 2583 free(name); 2584 continue; 2585 } 2586 *val++ = '\0'; 2587 2588 matched = 0; 2589 for (j = 0; j < options.num_send_env; j++) { 2590 if (match_pattern(name, options.send_env[j])) { 2591 matched = 1; 2592 break; 2593 } 2594 } 2595 if (!matched) { 2596 debug3("Ignored env %s", name); 2597 free(name); 2598 continue; 2599 } 2600 client_send_env(ssh, id, name, val); 2601 free(name); 2602 } 2603 } 2604 for (i = 0; i < options.num_setenv; i++) { 2605 /* Split */ 2606 name = xstrdup(options.setenv[i]); 2607 if ((val = strchr(name, '=')) == NULL) { 2608 free(name); 2609 continue; 2610 } 2611 *val++ = '\0'; 2612 client_send_env(ssh, id, name, val); 2613 free(name); 2614 } 2615 2616 len = sshbuf_len(cmd); 2617 if (len > 0) { 2618 if (len > 900) 2619 len = 900; 2620 if (want_subsystem) { 2621 debug("Sending subsystem: %.*s", 2622 (int)len, (const u_char*)sshbuf_ptr(cmd)); 2623 channel_request_start(ssh, id, "subsystem", 1); 2624 client_expect_confirm(ssh, id, "subsystem", 2625 CONFIRM_CLOSE); 2626 } else { 2627 debug("Sending command: %.*s", 2628 (int)len, (const u_char*)sshbuf_ptr(cmd)); 2629 channel_request_start(ssh, id, "exec", 1); 2630 client_expect_confirm(ssh, id, "exec", CONFIRM_CLOSE); 2631 } 2632 if ((r = sshpkt_put_stringb(ssh, cmd)) != 0 || 2633 (r = sshpkt_send(ssh)) != 0) 2634 fatal_fr(r, "send command"); 2635 } else { 2636 channel_request_start(ssh, id, "shell", 1); 2637 client_expect_confirm(ssh, id, "shell", CONFIRM_CLOSE); 2638 if ((r = sshpkt_send(ssh)) != 0) 2639 fatal_fr(r, "send shell"); 2640 } 2641 2642 session_setup_complete = 1; 2643 client_repledge(); 2644 } 2645 2646 static void 2647 client_init_dispatch(struct ssh *ssh) 2648 { 2649 ssh_dispatch_init(ssh, &dispatch_protocol_error); 2650 2651 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); 2652 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_DATA, &channel_input_data); 2653 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); 2654 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); 2655 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open); 2656 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 2657 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 2658 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req); 2659 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); 2660 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm); 2661 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm); 2662 ssh_dispatch_set(ssh, SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request); 2663 2664 /* rekeying */ 2665 ssh_dispatch_set(ssh, SSH2_MSG_KEXINIT, &kex_input_kexinit); 2666 2667 /* global request reply messages */ 2668 ssh_dispatch_set(ssh, SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply); 2669 ssh_dispatch_set(ssh, SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply); 2670 } 2671 2672 void 2673 client_stop_mux(void) 2674 { 2675 if (options.control_path != NULL && muxserver_sock != -1) 2676 unlink(options.control_path); 2677 /* 2678 * If we are in persist mode, or don't have a shell, signal that we 2679 * should close when all active channels are closed. 2680 */ 2681 if (options.control_persist || options.session_type == SESSION_TYPE_NONE) { 2682 session_closed = 1; 2683 setproctitle("[stopped mux]"); 2684 } 2685 } 2686 2687 /* client specific fatal cleanup */ 2688 void 2689 cleanup_exit(int i) 2690 { 2691 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 2692 if (options.control_path != NULL && muxserver_sock != -1) 2693 unlink(options.control_path); 2694 ssh_kill_proxy_command(); 2695 _exit(i); 2696 } 2697