1 /* $NetBSD: clientloop.c,v 1.37 2023/07/26 17:58:15 christos Exp $ */ 2 /* $OpenBSD: clientloop.c,v 1.390 2023/03/08 04:43:12 guenther Exp $ */ 3 /* 4 * Author: Tatu Ylonen <ylo@cs.hut.fi> 5 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 6 * All rights reserved 7 * The main loop for the interactive session (client side). 8 * 9 * As far as I am concerned, the code I have written for this software 10 * can be used freely for any purpose. Any derived versions of this 11 * software must be clearly marked as such, and if the derived work is 12 * incompatible with the protocol description in the RFC file, it must be 13 * called by a name other than "ssh" or "Secure Shell". 14 * 15 * 16 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 17 * 18 * Redistribution and use in source and binary forms, with or without 19 * modification, are permitted provided that the following conditions 20 * are met: 21 * 1. Redistributions of source code must retain the above copyright 22 * notice, this list of conditions and the following disclaimer. 23 * 2. Redistributions in binary form must reproduce the above copyright 24 * notice, this list of conditions and the following disclaimer in the 25 * documentation and/or other materials provided with the distribution. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 28 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 29 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 30 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 31 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 32 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 33 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 34 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 35 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 36 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 37 * 38 * 39 * SSH2 support added by Markus Friedl. 40 * Copyright (c) 1999, 2000, 2001 Markus Friedl. All rights reserved. 41 * 42 * Redistribution and use in source and binary forms, with or without 43 * modification, are permitted provided that the following conditions 44 * are met: 45 * 1. Redistributions of source code must retain the above copyright 46 * notice, this list of conditions and the following disclaimer. 47 * 2. Redistributions in binary form must reproduce the above copyright 48 * notice, this list of conditions and the following disclaimer in the 49 * documentation and/or other materials provided with the distribution. 50 * 51 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 52 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 53 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 54 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 55 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 56 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 57 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 58 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 59 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 60 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 61 */ 62 63 #include "includes.h" 64 __RCSID("$NetBSD: clientloop.c,v 1.37 2023/07/26 17:58:15 christos Exp $"); 65 66 #include <sys/types.h> 67 #include <sys/ioctl.h> 68 #include <sys/stat.h> 69 #include <sys/socket.h> 70 #include <sys/time.h> 71 #include <sys/queue.h> 72 73 #include <ctype.h> 74 #include <errno.h> 75 #include <paths.h> 76 #include <poll.h> 77 #include <signal.h> 78 #include <stdio.h> 79 #include <stdlib.h> 80 #include <string.h> 81 #include <stdarg.h> 82 #include <termios.h> 83 #include <pwd.h> 84 #include <unistd.h> 85 #include <limits.h> 86 87 #include "xmalloc.h" 88 #include "ssh.h" 89 #include "ssh2.h" 90 #include "packet.h" 91 #include "sshbuf.h" 92 #include "compat.h" 93 #include "channels.h" 94 #include "dispatch.h" 95 #include "sshkey.h" 96 #include "cipher.h" 97 #include "kex.h" 98 #include "myproposal.h" 99 #include "log.h" 100 #include "misc.h" 101 #include "readconf.h" 102 #include "clientloop.h" 103 #include "sshconnect.h" 104 #include "authfd.h" 105 #include "atomicio.h" 106 #include "sshpty.h" 107 #include "match.h" 108 #include "msg.h" 109 #include "getpeereid.h" 110 #include "ssherr.h" 111 #include "hostfile.h" 112 113 /* Permitted RSA signature algorithms for UpdateHostkeys proofs */ 114 #define HOSTKEY_PROOF_RSA_ALGS "rsa-sha2-512,rsa-sha2-256" 115 116 /* import options */ 117 extern Options options; 118 119 /* Control socket */ 120 extern int muxserver_sock; /* XXX use mux_client_cleanup() instead */ 121 122 /* 123 * Name of the host we are connecting to. This is the name given on the 124 * command line, or the Hostname specified for the user-supplied name in a 125 * configuration file. 126 */ 127 extern char *host; 128 129 /* 130 * If this field is not NULL, the ForwardAgent socket is this path and different 131 * instead of SSH_AUTH_SOCK. 132 */ 133 extern char *forward_agent_sock_path; 134 135 /* 136 * Flag to indicate that we have received a window change signal which has 137 * not yet been processed. This will cause a message indicating the new 138 * window size to be sent to the server a little later. This is volatile 139 * because this is updated in a signal handler. 140 */ 141 static volatile sig_atomic_t received_window_change_signal = 0; 142 static volatile sig_atomic_t received_signal = 0; 143 144 /* Time when backgrounded control master using ControlPersist should exit */ 145 static time_t control_persist_exit_time = 0; 146 147 /* Common data for the client loop code. */ 148 volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */ 149 static int last_was_cr; /* Last character was a newline. */ 150 static int exit_status; /* Used to store the command exit status. */ 151 static struct sshbuf *stderr_buffer; /* Used for final exit message. */ 152 static int connection_in; /* Connection to server (input). */ 153 static int connection_out; /* Connection to server (output). */ 154 static int need_rekeying; /* Set to non-zero if rekeying is requested. */ 155 static int session_closed; /* In SSH2: login session closed. */ 156 static time_t x11_refuse_time; /* If >0, refuse x11 opens after this time. */ 157 static time_t server_alive_time; /* Time to do server_alive_check */ 158 static int hostkeys_update_complete; 159 static int session_setup_complete; 160 161 static void client_init_dispatch(struct ssh *ssh); 162 int session_ident = -1; 163 164 /* Track escape per proto2 channel */ 165 struct escape_filter_ctx { 166 int escape_pending; 167 int escape_char; 168 }; 169 170 /* Context for channel confirmation replies */ 171 struct channel_reply_ctx { 172 const char *request_type; 173 int id; 174 enum confirm_action action; 175 }; 176 177 /* Global request success/failure callbacks */ 178 /* XXX move to struct ssh? */ 179 struct global_confirm { 180 TAILQ_ENTRY(global_confirm) entry; 181 global_confirm_cb *cb; 182 void *ctx; 183 int ref_count; 184 }; 185 TAILQ_HEAD(global_confirms, global_confirm); 186 static struct global_confirms global_confirms = 187 TAILQ_HEAD_INITIALIZER(global_confirms); 188 189 void ssh_process_session2_setup(int, int, int, struct sshbuf *); 190 static void quit_message(const char *fmt, ...) 191 __attribute__((__format__ (printf, 1, 2))); 192 193 static void 194 quit_message(const char *fmt, ...) 195 { 196 char *msg; 197 va_list args; 198 int r; 199 200 va_start(args, fmt); 201 xvasprintf(&msg, fmt, args); 202 va_end(args); 203 204 if ((r = sshbuf_putf(stderr_buffer, "%s\r\n", msg)) != 0) 205 fatal_fr(r, "sshbuf_putf"); 206 quit_pending = 1; 207 } 208 209 /* 210 * Signal handler for the window change signal (SIGWINCH). This just sets a 211 * flag indicating that the window has changed. 212 */ 213 static void 214 window_change_handler(int sig) 215 { 216 received_window_change_signal = 1; 217 } 218 219 /* 220 * Signal handler for signals that cause the program to terminate. These 221 * signals must be trapped to restore terminal modes. 222 */ 223 static void 224 signal_handler(int sig) 225 { 226 received_signal = sig; 227 quit_pending = 1; 228 } 229 230 /* 231 * Sets control_persist_exit_time to the absolute time when the 232 * backgrounded control master should exit due to expiry of the 233 * ControlPersist timeout. Sets it to 0 if we are not a backgrounded 234 * control master process, or if there is no ControlPersist timeout. 235 */ 236 static void 237 set_control_persist_exit_time(struct ssh *ssh) 238 { 239 if (muxserver_sock == -1 || !options.control_persist 240 || options.control_persist_timeout == 0) { 241 /* not using a ControlPersist timeout */ 242 control_persist_exit_time = 0; 243 } else if (channel_still_open(ssh)) { 244 /* some client connections are still open */ 245 if (control_persist_exit_time > 0) 246 debug2_f("cancel scheduled exit"); 247 control_persist_exit_time = 0; 248 } else if (control_persist_exit_time <= 0) { 249 /* a client connection has recently closed */ 250 control_persist_exit_time = monotime() + 251 (time_t)options.control_persist_timeout; 252 debug2_f("schedule exit in %d seconds", 253 options.control_persist_timeout); 254 } 255 /* else we are already counting down to the timeout */ 256 } 257 258 #define SSH_X11_VALID_DISPLAY_CHARS ":/.-_" 259 static int 260 client_x11_display_valid(const char *display) 261 { 262 size_t i, dlen; 263 264 if (display == NULL) 265 return 0; 266 267 dlen = strlen(display); 268 for (i = 0; i < dlen; i++) { 269 if (!isalnum((u_char)display[i]) && 270 strchr(SSH_X11_VALID_DISPLAY_CHARS, display[i]) == NULL) { 271 debug("Invalid character '%c' in DISPLAY", display[i]); 272 return 0; 273 } 274 } 275 return 1; 276 } 277 278 #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1" 279 #define X11_TIMEOUT_SLACK 60 280 int 281 client_x11_get_proto(struct ssh *ssh, const char *display, 282 const char *xauth_path, u_int trusted, u_int timeout, 283 char **_proto, char **_data) 284 { 285 char *cmd, line[512], xdisplay[512]; 286 char xauthfile[PATH_MAX], xauthdir[PATH_MAX]; 287 static char proto[512], data[512]; 288 FILE *f; 289 int got_data = 0, generated = 0, do_unlink = 0, r; 290 struct stat st; 291 u_int now, x11_timeout_real; 292 293 *_proto = proto; 294 *_data = data; 295 proto[0] = data[0] = xauthfile[0] = xauthdir[0] = '\0'; 296 297 if (!client_x11_display_valid(display)) { 298 if (display != NULL) 299 logit("DISPLAY \"%s\" invalid; disabling X11 forwarding", 300 display); 301 return -1; 302 } 303 if (xauth_path != NULL && stat(xauth_path, &st) == -1) { 304 debug("No xauth program."); 305 xauth_path = NULL; 306 } 307 308 if (xauth_path != NULL) { 309 /* 310 * Handle FamilyLocal case where $DISPLAY does 311 * not match an authorization entry. For this we 312 * just try "xauth list unix:displaynum.screennum". 313 * XXX: "localhost" match to determine FamilyLocal 314 * is not perfect. 315 */ 316 if (strncmp(display, "localhost:", 10) == 0) { 317 if ((r = snprintf(xdisplay, sizeof(xdisplay), "unix:%s", 318 display + 10)) < 0 || 319 (size_t)r >= sizeof(xdisplay)) { 320 error_f("display name too long"); 321 return -1; 322 } 323 display = xdisplay; 324 } 325 if (trusted == 0) { 326 /* 327 * Generate an untrusted X11 auth cookie. 328 * 329 * The authentication cookie should briefly outlive 330 * ssh's willingness to forward X11 connections to 331 * avoid nasty fail-open behaviour in the X server. 332 */ 333 mktemp_proto(xauthdir, sizeof(xauthdir)); 334 if (mkdtemp(xauthdir) == NULL) { 335 error_f("mkdtemp: %s", strerror(errno)); 336 return -1; 337 } 338 do_unlink = 1; 339 if ((r = snprintf(xauthfile, sizeof(xauthfile), 340 "%s/xauthfile", xauthdir)) < 0 || 341 (size_t)r >= sizeof(xauthfile)) { 342 error_f("xauthfile path too long"); 343 rmdir(xauthdir); 344 return -1; 345 } 346 347 if (timeout == 0) { 348 /* auth doesn't time out */ 349 xasprintf(&cmd, "%s -f %s generate %s %s " 350 "untrusted 2>%s", 351 xauth_path, xauthfile, display, 352 SSH_X11_PROTO, _PATH_DEVNULL); 353 } else { 354 /* Add some slack to requested expiry */ 355 if (timeout < UINT_MAX - X11_TIMEOUT_SLACK) 356 x11_timeout_real = timeout + 357 X11_TIMEOUT_SLACK; 358 else { 359 /* Don't overflow on long timeouts */ 360 x11_timeout_real = UINT_MAX; 361 } 362 xasprintf(&cmd, "%s -f %s generate %s %s " 363 "untrusted timeout %u 2>%s", 364 xauth_path, xauthfile, display, 365 SSH_X11_PROTO, x11_timeout_real, 366 _PATH_DEVNULL); 367 } 368 debug2_f("xauth command: %s", cmd); 369 370 if (timeout != 0 && x11_refuse_time == 0) { 371 now = monotime() + 1; 372 if (SSH_TIME_T_MAX - timeout < now) 373 x11_refuse_time = SSH_TIME_T_MAX; 374 else 375 x11_refuse_time = now + timeout; 376 channel_set_x11_refuse_time(ssh, 377 x11_refuse_time); 378 } 379 if (system(cmd) == 0) 380 generated = 1; 381 free(cmd); 382 } 383 384 /* 385 * When in untrusted mode, we read the cookie only if it was 386 * successfully generated as an untrusted one in the step 387 * above. 388 */ 389 if (trusted || generated) { 390 xasprintf(&cmd, 391 "%s %s%s list %s 2>" _PATH_DEVNULL, 392 xauth_path, 393 generated ? "-f " : "" , 394 generated ? xauthfile : "", 395 display); 396 debug2("x11_get_proto: %s", cmd); 397 f = popen(cmd, "r"); 398 if (f && fgets(line, sizeof(line), f) && 399 sscanf(line, "%*s %511s %511s", proto, data) == 2) 400 got_data = 1; 401 if (f) 402 pclose(f); 403 free(cmd); 404 } 405 } 406 407 if (do_unlink) { 408 unlink(xauthfile); 409 rmdir(xauthdir); 410 } 411 412 /* Don't fall back to fake X11 data for untrusted forwarding */ 413 if (!trusted && !got_data) { 414 error("Warning: untrusted X11 forwarding setup failed: " 415 "xauth key data not generated"); 416 return -1; 417 } 418 419 /* 420 * If we didn't get authentication data, just make up some 421 * data. The forwarding code will check the validity of the 422 * response anyway, and substitute this data. The X11 423 * server, however, will ignore this fake data and use 424 * whatever authentication mechanisms it was using otherwise 425 * for the local connection. 426 */ 427 if (!got_data) { 428 u_int8_t rnd[16]; 429 u_int i; 430 431 logit("Warning: No xauth data; " 432 "using fake authentication data for X11 forwarding."); 433 strlcpy(proto, SSH_X11_PROTO, sizeof proto); 434 arc4random_buf(rnd, sizeof(rnd)); 435 for (i = 0; i < sizeof(rnd); i++) { 436 snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", 437 rnd[i]); 438 } 439 } 440 441 return 0; 442 } 443 444 /* 445 * Checks if the client window has changed, and sends a packet about it to 446 * the server if so. The actual change is detected elsewhere (by a software 447 * interrupt on Unix); this just checks the flag and sends a message if 448 * appropriate. 449 */ 450 451 static void 452 client_check_window_change(struct ssh *ssh) 453 { 454 if (!received_window_change_signal) 455 return; 456 received_window_change_signal = 0; 457 debug2_f("changed"); 458 channel_send_window_changes(ssh); 459 } 460 461 static int 462 client_global_request_reply(int type, u_int32_t seq, struct ssh *ssh) 463 { 464 struct global_confirm *gc; 465 466 if ((gc = TAILQ_FIRST(&global_confirms)) == NULL) 467 return 0; 468 if (gc->cb != NULL) 469 gc->cb(ssh, type, seq, gc->ctx); 470 if (--gc->ref_count <= 0) { 471 TAILQ_REMOVE(&global_confirms, gc, entry); 472 freezero(gc, sizeof(*gc)); 473 } 474 475 ssh_packet_set_alive_timeouts(ssh, 0); 476 return 0; 477 } 478 479 static void 480 schedule_server_alive_check(void) 481 { 482 if (options.server_alive_interval > 0) 483 server_alive_time = monotime() + options.server_alive_interval; 484 } 485 486 static void 487 server_alive_check(struct ssh *ssh) 488 { 489 int r; 490 491 if (ssh_packet_inc_alive_timeouts(ssh) > options.server_alive_count_max) { 492 logit("Timeout, server %s not responding.", host); 493 cleanup_exit(255); 494 } 495 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 496 (r = sshpkt_put_cstring(ssh, "keepalive@openssh.com")) != 0 || 497 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* boolean: want reply */ 498 (r = sshpkt_send(ssh)) != 0) 499 fatal_fr(r, "send packet"); 500 /* Insert an empty placeholder to maintain ordering */ 501 client_register_global_confirm(NULL, NULL); 502 schedule_server_alive_check(); 503 } 504 505 /* 506 * Waits until the client can do something (some data becomes available on 507 * one of the file descriptors). 508 */ 509 static void 510 client_wait_until_can_do_something(struct ssh *ssh, struct pollfd **pfdp, 511 u_int *npfd_allocp, u_int *npfd_activep, int rekeying, 512 int *conn_in_readyp, int *conn_out_readyp) 513 { 514 struct timespec timeout; 515 int ret; 516 u_int p; 517 518 *conn_in_readyp = *conn_out_readyp = 0; 519 520 /* Prepare channel poll. First two pollfd entries are reserved */ 521 ptimeout_init(&timeout); 522 channel_prepare_poll(ssh, pfdp, npfd_allocp, npfd_activep, 2, &timeout); 523 if (*npfd_activep < 2) 524 fatal_f("bad npfd %u", *npfd_activep); /* shouldn't happen */ 525 526 /* channel_prepare_poll could have closed the last channel */ 527 if (session_closed && !channel_still_open(ssh) && 528 !ssh_packet_have_data_to_write(ssh)) { 529 /* clear events since we did not call poll() */ 530 for (p = 0; p < *npfd_activep; p++) 531 (*pfdp)[p].revents = 0; 532 return; 533 } 534 535 /* Monitor server connection on reserved pollfd entries */ 536 (*pfdp)[0].fd = connection_in; 537 (*pfdp)[0].events = POLLIN; 538 (*pfdp)[1].fd = connection_out; 539 (*pfdp)[1].events = ssh_packet_have_data_to_write(ssh) ? POLLOUT : 0; 540 541 /* 542 * Wait for something to happen. This will suspend the process until 543 * some polled descriptor can be read, written, or has some other 544 * event pending, or a timeout expires. 545 */ 546 set_control_persist_exit_time(ssh); 547 if (control_persist_exit_time > 0) 548 ptimeout_deadline_monotime(&timeout, control_persist_exit_time); 549 if (options.server_alive_interval > 0) 550 ptimeout_deadline_monotime(&timeout, server_alive_time); 551 if (options.rekey_interval > 0 && !rekeying) { 552 ptimeout_deadline_sec(&timeout, 553 ssh_packet_get_rekey_timeout(ssh)); 554 } 555 556 ret = poll(*pfdp, *npfd_activep, ptimeout_get_ms(&timeout)); 557 558 if (ret == -1) { 559 /* 560 * We have to clear the events because we return. 561 * We have to return, because the mainloop checks for the flags 562 * set by the signal handlers. 563 */ 564 for (p = 0; p < *npfd_activep; p++) 565 (*pfdp)[p].revents = 0; 566 if (errno == EINTR) 567 return; 568 /* Note: we might still have data in the buffers. */ 569 quit_message("poll: %s", strerror(errno)); 570 return; 571 } 572 573 *conn_in_readyp = (*pfdp)[0].revents != 0; 574 *conn_out_readyp = (*pfdp)[1].revents != 0; 575 576 if (options.server_alive_interval > 0 && !*conn_in_readyp && 577 monotime() >= server_alive_time) { 578 /* 579 * ServerAlive check is needed. We can't rely on the poll 580 * timing out since traffic on the client side such as port 581 * forwards can keep waking it up. 582 */ 583 server_alive_check(ssh); 584 } 585 } 586 587 static void 588 client_suspend_self(struct sshbuf *bin, struct sshbuf *bout, struct sshbuf *berr) 589 { 590 /* Flush stdout and stderr buffers. */ 591 if (sshbuf_len(bout) > 0) 592 atomicio(vwrite, fileno(stdout), sshbuf_mutable_ptr(bout), 593 sshbuf_len(bout)); 594 if (sshbuf_len(berr) > 0) 595 atomicio(vwrite, fileno(stderr), sshbuf_mutable_ptr(berr), 596 sshbuf_len(berr)); 597 598 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 599 600 sshbuf_reset(bin); 601 sshbuf_reset(bout); 602 sshbuf_reset(berr); 603 604 /* Send the suspend signal to the program itself. */ 605 kill(getpid(), SIGTSTP); 606 607 /* Reset window sizes in case they have changed */ 608 received_window_change_signal = 1; 609 610 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 611 } 612 613 static void 614 client_process_net_input(struct ssh *ssh) 615 { 616 int r; 617 618 /* 619 * Read input from the server, and add any such data to the buffer of 620 * the packet subsystem. 621 */ 622 schedule_server_alive_check(); 623 if ((r = ssh_packet_process_read(ssh, connection_in)) == 0) 624 return; /* success */ 625 if (r == SSH_ERR_SYSTEM_ERROR) { 626 if (errno == EAGAIN || errno == EINTR) 627 return; 628 if (errno == EPIPE) { 629 quit_message("Connection to %s closed by remote host.", 630 host); 631 return; 632 } 633 } 634 quit_message("Read from remote host %s: %s", host, ssh_err(r)); 635 } 636 637 static void 638 client_status_confirm(struct ssh *ssh, int type, Channel *c, void *ctx) 639 { 640 struct channel_reply_ctx *cr = (struct channel_reply_ctx *)ctx; 641 char errmsg[256]; 642 int r, tochan; 643 644 /* 645 * If a TTY was explicitly requested, then a failure to allocate 646 * one is fatal. 647 */ 648 if (cr->action == CONFIRM_TTY && 649 (options.request_tty == REQUEST_TTY_FORCE || 650 options.request_tty == REQUEST_TTY_YES)) 651 cr->action = CONFIRM_CLOSE; 652 653 /* XXX suppress on mux _client_ quietmode */ 654 tochan = options.log_level >= SYSLOG_LEVEL_ERROR && 655 c->ctl_chan != -1 && c->extended_usage == CHAN_EXTENDED_WRITE; 656 657 if (type == SSH2_MSG_CHANNEL_SUCCESS) { 658 debug2("%s request accepted on channel %d", 659 cr->request_type, c->self); 660 } else if (type == SSH2_MSG_CHANNEL_FAILURE) { 661 if (tochan) { 662 snprintf(errmsg, sizeof(errmsg), 663 "%s request failed\r\n", cr->request_type); 664 } else { 665 snprintf(errmsg, sizeof(errmsg), 666 "%s request failed on channel %d", 667 cr->request_type, c->self); 668 } 669 /* If error occurred on primary session channel, then exit */ 670 if (cr->action == CONFIRM_CLOSE && c->self == session_ident) 671 fatal("%s", errmsg); 672 /* 673 * If error occurred on mux client, append to 674 * their stderr. 675 */ 676 if (tochan) { 677 debug3_f("channel %d: mux request: %s", c->self, 678 cr->request_type); 679 if ((r = sshbuf_put(c->extended, errmsg, 680 strlen(errmsg))) != 0) 681 fatal_fr(r, "sshbuf_put"); 682 } else 683 error("%s", errmsg); 684 if (cr->action == CONFIRM_TTY) { 685 /* 686 * If a TTY allocation error occurred, then arrange 687 * for the correct TTY to leave raw mode. 688 */ 689 if (c->self == session_ident) 690 leave_raw_mode(0); 691 else 692 mux_tty_alloc_failed(ssh, c); 693 } else if (cr->action == CONFIRM_CLOSE) { 694 chan_read_failed(ssh, c); 695 chan_write_failed(ssh, c); 696 } 697 } 698 free(cr); 699 } 700 701 static void 702 client_abandon_status_confirm(struct ssh *ssh, Channel *c, void *ctx) 703 { 704 free(ctx); 705 } 706 707 void 708 client_expect_confirm(struct ssh *ssh, int id, const char *request, 709 enum confirm_action action) 710 { 711 struct channel_reply_ctx *cr = xcalloc(1, sizeof(*cr)); 712 713 cr->request_type = request; 714 cr->action = action; 715 716 channel_register_status_confirm(ssh, id, client_status_confirm, 717 client_abandon_status_confirm, cr); 718 } 719 720 void 721 client_register_global_confirm(global_confirm_cb *cb, void *ctx) 722 { 723 struct global_confirm *gc, *last_gc; 724 725 /* Coalesce identical callbacks */ 726 last_gc = TAILQ_LAST(&global_confirms, global_confirms); 727 if (last_gc && last_gc->cb == cb && last_gc->ctx == ctx) { 728 if (++last_gc->ref_count >= INT_MAX) 729 fatal_f("last_gc->ref_count = %d", 730 last_gc->ref_count); 731 return; 732 } 733 734 gc = xcalloc(1, sizeof(*gc)); 735 gc->cb = cb; 736 gc->ctx = ctx; 737 gc->ref_count = 1; 738 TAILQ_INSERT_TAIL(&global_confirms, gc, entry); 739 } 740 741 /* 742 * Returns non-zero if the client is able to handle a hostkeys-00@openssh.com 743 * hostkey update request. 744 */ 745 static int 746 can_update_hostkeys(void) 747 { 748 if (hostkeys_update_complete) 749 return 0; 750 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK && 751 options.batch_mode) 752 return 0; /* won't ask in batchmode, so don't even try */ 753 if (!options.update_hostkeys || options.num_user_hostfiles <= 0) 754 return 0; 755 return 1; 756 } 757 758 static void 759 client_repledge(void) 760 { 761 debug3_f("enter"); 762 763 /* Might be able to tighten pledge now that session is established */ 764 if (options.control_master || options.control_path != NULL || 765 options.forward_x11 || options.fork_after_authentication || 766 can_update_hostkeys() || 767 (session_ident != -1 && !session_setup_complete)) { 768 /* Can't tighten */ 769 return; 770 } 771 #ifdef __OpenBSD__ 772 /* 773 * LocalCommand and UpdateHostkeys have finished, so can get rid of 774 * filesystem. 775 * 776 * XXX protocol allows a server can to change hostkeys during the 777 * connection at rekey time that could trigger a hostkeys update 778 * but AFAIK no implementations support this. Could improve by 779 * forcing known_hosts to be read-only or via unveil(2). 780 */ 781 if (options.num_local_forwards != 0 || 782 options.num_remote_forwards != 0 || 783 options.num_permitted_remote_opens != 0 || 784 options.enable_escape_commandline != 0) { 785 /* rfwd needs inet */ 786 debug("pledge: network"); 787 if (pledge("stdio unix inet dns proc tty", NULL) == -1) 788 fatal_f("pledge(): %s", strerror(errno)); 789 } else if (options.forward_agent != 0) { 790 /* agent forwarding needs to open $SSH_AUTH_SOCK at will */ 791 debug("pledge: agent"); 792 if (pledge("stdio unix proc tty", NULL) == -1) 793 fatal_f("pledge(): %s", strerror(errno)); 794 } else { 795 debug("pledge: fork"); 796 if (pledge("stdio proc tty", NULL) == -1) 797 fatal_f("pledge(): %s", strerror(errno)); 798 } 799 #endif 800 /* XXX further things to do: 801 * 802 * - might be able to get rid of proc if we kill ~^Z 803 * - ssh -N (no session) 804 * - stdio forwarding 805 * - sessions without tty 806 */ 807 } 808 809 static void 810 process_cmdline(struct ssh *ssh) 811 { 812 void (*handler)(int); 813 char *s, *cmd; 814 int ok, delete = 0, local = 0, remote = 0, dynamic = 0; 815 struct Forward fwd; 816 817 memset(&fwd, 0, sizeof(fwd)); 818 819 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 820 handler = ssh_signal(SIGINT, SIG_IGN); 821 cmd = s = read_passphrase("\r\nssh> ", RP_ECHO); 822 if (s == NULL) 823 goto out; 824 while (isspace((u_char)*s)) 825 s++; 826 if (*s == '-') 827 s++; /* Skip cmdline '-', if any */ 828 if (*s == '\0') 829 goto out; 830 831 if (*s == 'h' || *s == 'H' || *s == '?') { 832 logit("Commands:"); 833 logit(" -L[bind_address:]port:host:hostport " 834 "Request local forward"); 835 logit(" -R[bind_address:]port:host:hostport " 836 "Request remote forward"); 837 logit(" -D[bind_address:]port " 838 "Request dynamic forward"); 839 logit(" -KL[bind_address:]port " 840 "Cancel local forward"); 841 logit(" -KR[bind_address:]port " 842 "Cancel remote forward"); 843 logit(" -KD[bind_address:]port " 844 "Cancel dynamic forward"); 845 if (!options.permit_local_command) 846 goto out; 847 logit(" !args " 848 "Execute local command"); 849 goto out; 850 } 851 852 if (*s == '!' && options.permit_local_command) { 853 s++; 854 ssh_local_cmd(s); 855 goto out; 856 } 857 858 if (*s == 'K') { 859 delete = 1; 860 s++; 861 } 862 if (*s == 'L') 863 local = 1; 864 else if (*s == 'R') 865 remote = 1; 866 else if (*s == 'D') 867 dynamic = 1; 868 else { 869 logit("Invalid command."); 870 goto out; 871 } 872 873 while (isspace((u_char)*++s)) 874 ; 875 876 /* XXX update list of forwards in options */ 877 if (delete) { 878 /* We pass 1 for dynamicfwd to restrict to 1 or 2 fields. */ 879 if (!parse_forward(&fwd, s, 1, 0)) { 880 logit("Bad forwarding close specification."); 881 goto out; 882 } 883 if (remote) 884 ok = channel_request_rforward_cancel(ssh, &fwd) == 0; 885 else if (dynamic) 886 ok = channel_cancel_lport_listener(ssh, &fwd, 887 0, &options.fwd_opts) > 0; 888 else 889 ok = channel_cancel_lport_listener(ssh, &fwd, 890 CHANNEL_CANCEL_PORT_STATIC, 891 &options.fwd_opts) > 0; 892 if (!ok) { 893 logit("Unknown port forwarding."); 894 goto out; 895 } 896 logit("Canceled forwarding."); 897 } else { 898 /* -R specs can be both dynamic or not, so check both. */ 899 if (remote) { 900 if (!parse_forward(&fwd, s, 0, remote) && 901 !parse_forward(&fwd, s, 1, remote)) { 902 logit("Bad remote forwarding specification."); 903 goto out; 904 } 905 } else if (!parse_forward(&fwd, s, dynamic, remote)) { 906 logit("Bad local forwarding specification."); 907 goto out; 908 } 909 if (local || dynamic) { 910 if (!channel_setup_local_fwd_listener(ssh, &fwd, 911 &options.fwd_opts)) { 912 logit("Port forwarding failed."); 913 goto out; 914 } 915 } else { 916 if (channel_request_remote_forwarding(ssh, &fwd) < 0) { 917 logit("Port forwarding failed."); 918 goto out; 919 } 920 } 921 logit("Forwarding port."); 922 } 923 924 out: 925 ssh_signal(SIGINT, handler); 926 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 927 free(cmd); 928 free(fwd.listen_host); 929 free(fwd.listen_path); 930 free(fwd.connect_host); 931 free(fwd.connect_path); 932 } 933 934 /* reasons to suppress output of an escape command in help output */ 935 #define SUPPRESS_NEVER 0 /* never suppress, always show */ 936 #define SUPPRESS_MUXCLIENT 1 /* don't show in mux client sessions */ 937 #define SUPPRESS_MUXMASTER 2 /* don't show in mux master sessions */ 938 #define SUPPRESS_SYSLOG 4 /* don't show when logging to syslog */ 939 #define SUPPRESS_NOCMDLINE 8 /* don't show when cmdline disabled*/ 940 struct escape_help_text { 941 const char *cmd; 942 const char *text; 943 unsigned int flags; 944 }; 945 static struct escape_help_text esc_txt[] = { 946 {".", "terminate session", SUPPRESS_MUXMASTER}, 947 {".", "terminate connection (and any multiplexed sessions)", 948 SUPPRESS_MUXCLIENT}, 949 {"B", "send a BREAK to the remote system", SUPPRESS_NEVER}, 950 {"C", "open a command line", SUPPRESS_MUXCLIENT|SUPPRESS_NOCMDLINE}, 951 {"R", "request rekey", SUPPRESS_NEVER}, 952 {"V/v", "decrease/increase verbosity (LogLevel)", SUPPRESS_MUXCLIENT}, 953 {"^Z", "suspend ssh", SUPPRESS_MUXCLIENT}, 954 {"#", "list forwarded connections", SUPPRESS_NEVER}, 955 {"&", "background ssh (when waiting for connections to terminate)", 956 SUPPRESS_MUXCLIENT}, 957 {"?", "this message", SUPPRESS_NEVER}, 958 }; 959 960 static void 961 print_escape_help(struct sshbuf *b, int escape_char, int mux_client, 962 int using_stderr) 963 { 964 unsigned int i, suppress_flags; 965 int r; 966 967 if ((r = sshbuf_putf(b, 968 "%c?\r\nSupported escape sequences:\r\n", escape_char)) != 0) 969 fatal_fr(r, "sshbuf_putf"); 970 971 suppress_flags = 972 (mux_client ? SUPPRESS_MUXCLIENT : 0) | 973 (mux_client ? 0 : SUPPRESS_MUXMASTER) | 974 (using_stderr ? 0 : SUPPRESS_SYSLOG) | 975 (options.enable_escape_commandline == 0 ? SUPPRESS_NOCMDLINE : 0); 976 977 for (i = 0; i < sizeof(esc_txt)/sizeof(esc_txt[0]); i++) { 978 if (esc_txt[i].flags & suppress_flags) 979 continue; 980 if ((r = sshbuf_putf(b, " %c%-3s - %s\r\n", 981 escape_char, esc_txt[i].cmd, esc_txt[i].text)) != 0) 982 fatal_fr(r, "sshbuf_putf"); 983 } 984 985 if ((r = sshbuf_putf(b, 986 " %c%c - send the escape character by typing it twice\r\n" 987 "(Note that escapes are only recognized immediately after " 988 "newline.)\r\n", escape_char, escape_char)) != 0) 989 fatal_fr(r, "sshbuf_putf"); 990 } 991 992 /* 993 * Process the characters one by one. 994 */ 995 static int 996 process_escapes(struct ssh *ssh, Channel *c, 997 struct sshbuf *bin, struct sshbuf *bout, struct sshbuf *berr, 998 const char *buf, int len) 999 { 1000 pid_t pid; 1001 int r, bytes = 0; 1002 u_int i; 1003 u_char ch; 1004 char *s; 1005 struct escape_filter_ctx *efc = c->filter_ctx == NULL ? 1006 NULL : (struct escape_filter_ctx *)c->filter_ctx; 1007 1008 if (c->filter_ctx == NULL) 1009 return 0; 1010 1011 if (len <= 0) 1012 return (0); 1013 1014 for (i = 0; i < (u_int)len; i++) { 1015 /* Get one character at a time. */ 1016 ch = buf[i]; 1017 1018 if (efc->escape_pending) { 1019 /* We have previously seen an escape character. */ 1020 /* Clear the flag now. */ 1021 efc->escape_pending = 0; 1022 1023 /* Process the escaped character. */ 1024 switch (ch) { 1025 case '.': 1026 /* Terminate the connection. */ 1027 if ((r = sshbuf_putf(berr, "%c.\r\n", 1028 efc->escape_char)) != 0) 1029 fatal_fr(r, "sshbuf_putf"); 1030 if (c && c->ctl_chan != -1) { 1031 channel_force_close(ssh, c, 1); 1032 return 0; 1033 } else 1034 quit_pending = 1; 1035 return -1; 1036 1037 case 'Z' - 64: 1038 /* XXX support this for mux clients */ 1039 if (c && c->ctl_chan != -1) { 1040 char b[16]; 1041 noescape: 1042 if (ch == 'Z' - 64) 1043 snprintf(b, sizeof b, "^Z"); 1044 else 1045 snprintf(b, sizeof b, "%c", ch); 1046 if ((r = sshbuf_putf(berr, 1047 "%c%s escape not available to " 1048 "multiplexed sessions\r\n", 1049 efc->escape_char, b)) != 0) 1050 fatal_fr(r, "sshbuf_putf"); 1051 continue; 1052 } 1053 /* Suspend the program. Inform the user */ 1054 if ((r = sshbuf_putf(berr, 1055 "%c^Z [suspend ssh]\r\n", 1056 efc->escape_char)) != 0) 1057 fatal_fr(r, "sshbuf_putf"); 1058 1059 /* Restore terminal modes and suspend. */ 1060 client_suspend_self(bin, bout, berr); 1061 1062 /* We have been continued. */ 1063 continue; 1064 1065 case 'B': 1066 if ((r = sshbuf_putf(berr, 1067 "%cB\r\n", efc->escape_char)) != 0) 1068 fatal_fr(r, "sshbuf_putf"); 1069 channel_request_start(ssh, c->self, "break", 0); 1070 if ((r = sshpkt_put_u32(ssh, 1000)) != 0 || 1071 (r = sshpkt_send(ssh)) != 0) 1072 fatal_fr(r, "send packet"); 1073 continue; 1074 1075 case 'R': 1076 if (ssh->compat & SSH_BUG_NOREKEY) 1077 logit("Server does not " 1078 "support re-keying"); 1079 else 1080 need_rekeying = 1; 1081 continue; 1082 1083 case 'V': 1084 /* FALLTHROUGH */ 1085 case 'v': 1086 if (c && c->ctl_chan != -1) 1087 goto noescape; 1088 if (!log_is_on_stderr()) { 1089 if ((r = sshbuf_putf(berr, 1090 "%c%c [Logging to syslog]\r\n", 1091 efc->escape_char, ch)) != 0) 1092 fatal_fr(r, "sshbuf_putf"); 1093 continue; 1094 } 1095 if (ch == 'V' && options.log_level > 1096 SYSLOG_LEVEL_QUIET) 1097 log_change_level(--options.log_level); 1098 if (ch == 'v' && options.log_level < 1099 SYSLOG_LEVEL_DEBUG3) 1100 log_change_level(++options.log_level); 1101 if ((r = sshbuf_putf(berr, 1102 "%c%c [LogLevel %s]\r\n", 1103 efc->escape_char, ch, 1104 log_level_name(options.log_level))) != 0) 1105 fatal_fr(r, "sshbuf_putf"); 1106 continue; 1107 1108 case '&': 1109 if (c && c->ctl_chan != -1) 1110 goto noescape; 1111 /* 1112 * Detach the program (continue to serve 1113 * connections, but put in background and no 1114 * more new connections). 1115 */ 1116 /* Restore tty modes. */ 1117 leave_raw_mode( 1118 options.request_tty == REQUEST_TTY_FORCE); 1119 1120 /* Stop listening for new connections. */ 1121 channel_stop_listening(ssh); 1122 1123 if ((r = sshbuf_putf(berr, "%c& " 1124 "[backgrounded]\n", efc->escape_char)) != 0) 1125 fatal_fr(r, "sshbuf_putf"); 1126 1127 /* Fork into background. */ 1128 pid = fork(); 1129 if (pid == -1) { 1130 error("fork: %.100s", strerror(errno)); 1131 continue; 1132 } 1133 if (pid != 0) { /* This is the parent. */ 1134 /* The parent just exits. */ 1135 exit(0); 1136 } 1137 /* The child continues serving connections. */ 1138 /* fake EOF on stdin */ 1139 if ((r = sshbuf_put_u8(bin, 4)) != 0) 1140 fatal_fr(r, "sshbuf_put_u8"); 1141 return -1; 1142 case '?': 1143 print_escape_help(berr, efc->escape_char, 1144 (c && c->ctl_chan != -1), 1145 log_is_on_stderr()); 1146 continue; 1147 1148 case '#': 1149 if ((r = sshbuf_putf(berr, "%c#\r\n", 1150 efc->escape_char)) != 0) 1151 fatal_fr(r, "sshbuf_putf"); 1152 s = channel_open_message(ssh); 1153 if ((r = sshbuf_put(berr, s, strlen(s))) != 0) 1154 fatal_fr(r, "sshbuf_put"); 1155 free(s); 1156 continue; 1157 1158 case 'C': 1159 if (c && c->ctl_chan != -1) 1160 goto noescape; 1161 if (options.enable_escape_commandline == 0) { 1162 if ((r = sshbuf_putf(berr, 1163 "commandline disabled\r\n")) != 0) 1164 fatal_fr(r, "sshbuf_putf"); 1165 continue; 1166 } 1167 process_cmdline(ssh); 1168 continue; 1169 1170 default: 1171 if (ch != efc->escape_char) { 1172 if ((r = sshbuf_put_u8(bin, 1173 efc->escape_char)) != 0) 1174 fatal_fr(r, "sshbuf_put_u8"); 1175 bytes++; 1176 } 1177 /* Escaped characters fall through here */ 1178 break; 1179 } 1180 } else { 1181 /* 1182 * The previous character was not an escape char. 1183 * Check if this is an escape. 1184 */ 1185 if (last_was_cr && ch == efc->escape_char) { 1186 /* 1187 * It is. Set the flag and continue to 1188 * next character. 1189 */ 1190 efc->escape_pending = 1; 1191 continue; 1192 } 1193 } 1194 1195 /* 1196 * Normal character. Record whether it was a newline, 1197 * and append it to the buffer. 1198 */ 1199 last_was_cr = (ch == '\r' || ch == '\n'); 1200 if ((r = sshbuf_put_u8(bin, ch)) != 0) 1201 fatal_fr(r, "sshbuf_put_u8"); 1202 bytes++; 1203 } 1204 return bytes; 1205 } 1206 1207 /* 1208 * Get packets from the connection input buffer, and process them as long as 1209 * there are packets available. 1210 * 1211 * Any unknown packets received during the actual 1212 * session cause the session to terminate. This is 1213 * intended to make debugging easier since no 1214 * confirmations are sent. Any compatible protocol 1215 * extensions must be negotiated during the 1216 * preparatory phase. 1217 */ 1218 1219 static void 1220 client_process_buffered_input_packets(struct ssh *ssh) 1221 { 1222 ssh_dispatch_run_fatal(ssh, DISPATCH_NONBLOCK, &quit_pending); 1223 } 1224 1225 /* scan buf[] for '~' before sending data to the peer */ 1226 1227 /* Helper: allocate a new escape_filter_ctx and fill in its escape char */ 1228 void * 1229 client_new_escape_filter_ctx(int escape_char) 1230 { 1231 struct escape_filter_ctx *ret; 1232 1233 ret = xcalloc(1, sizeof(*ret)); 1234 ret->escape_pending = 0; 1235 ret->escape_char = escape_char; 1236 return (void *)ret; 1237 } 1238 1239 /* Free the escape filter context on channel free */ 1240 void 1241 client_filter_cleanup(struct ssh *ssh, int cid, void *ctx) 1242 { 1243 free(ctx); 1244 } 1245 1246 int 1247 client_simple_escape_filter(struct ssh *ssh, Channel *c, const char *buf, 1248 int len) 1249 { 1250 if (c->extended_usage != CHAN_EXTENDED_WRITE) 1251 return 0; 1252 1253 return process_escapes(ssh, c, c->input, c->output, c->extended, 1254 buf, len); 1255 } 1256 1257 static void 1258 client_channel_closed(struct ssh *ssh, int id, int force, void *arg) 1259 { 1260 channel_cancel_cleanup(ssh, id); 1261 session_closed = 1; 1262 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1263 } 1264 1265 /* 1266 * Implements the interactive session with the server. This is called after 1267 * the user has been authenticated, and a command has been started on the 1268 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character 1269 * used as an escape character for terminating or suspending the session. 1270 */ 1271 int 1272 client_loop(struct ssh *ssh, int have_pty, int escape_char_arg, 1273 int ssh2_chan_id) 1274 { 1275 struct pollfd *pfd = NULL; 1276 u_int npfd_alloc = 0, npfd_active = 0; 1277 double start_time, total_time; 1278 int r, len; 1279 u_int64_t ibytes, obytes; 1280 int conn_in_ready, conn_out_ready; 1281 1282 debug("Entering interactive session."); 1283 session_ident = ssh2_chan_id; 1284 1285 #ifdef __OpenBSD__ 1286 if (options.control_master && 1287 !option_clear_or_none(options.control_path)) { 1288 debug("pledge: id"); 1289 if (pledge("stdio rpath wpath cpath unix inet dns recvfd sendfd proc exec id tty", 1290 NULL) == -1) 1291 fatal_f("pledge(): %s", strerror(errno)); 1292 1293 } else if (options.forward_x11 || options.permit_local_command) { 1294 debug("pledge: exec"); 1295 if (pledge("stdio rpath wpath cpath unix inet dns proc exec tty", 1296 NULL) == -1) 1297 fatal_f("pledge(): %s", strerror(errno)); 1298 1299 } else if (options.update_hostkeys) { 1300 debug("pledge: filesystem"); 1301 if (pledge("stdio rpath wpath cpath unix inet dns proc tty", 1302 NULL) == -1) 1303 fatal_f("pledge(): %s", strerror(errno)); 1304 1305 } else if (!option_clear_or_none(options.proxy_command) || 1306 options.fork_after_authentication) { 1307 debug("pledge: proc"); 1308 if (pledge("stdio cpath unix inet dns proc tty", NULL) == -1) 1309 fatal_f("pledge(): %s", strerror(errno)); 1310 1311 } else { 1312 debug("pledge: network"); 1313 if (pledge("stdio unix inet dns proc tty", NULL) == -1) 1314 fatal_f("pledge(): %s", strerror(errno)); 1315 } 1316 #endif 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 sshbuf_mutable_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 /* again is this really necessary for X11? */ 1636 if (options.hpn_disabled) 1637 c = channel_new(ssh, "x11", 1638 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1639 CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); 1640 else 1641 c = channel_new(ssh, "x11", 1642 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1643 options.hpn_buffer_size, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); 1644 c->force_drain = 1; 1645 return c; 1646 } 1647 1648 static Channel * 1649 client_request_agent(struct ssh *ssh, const char *request_type, int rchan) 1650 { 1651 Channel *c = NULL; 1652 int r, sock; 1653 1654 if (!options.forward_agent) { 1655 error("Warning: ssh server tried agent forwarding."); 1656 error("Warning: this is probably a break-in attempt by a " 1657 "malicious server."); 1658 return NULL; 1659 } 1660 if (forward_agent_sock_path == NULL) { 1661 r = ssh_get_authentication_socket(&sock); 1662 } else { 1663 r = ssh_get_authentication_socket_path(forward_agent_sock_path, &sock); 1664 } 1665 if (r != 0) { 1666 if (r != SSH_ERR_AGENT_NOT_PRESENT) 1667 debug_fr(r, "ssh_get_authentication_socket"); 1668 return NULL; 1669 } 1670 if ((r = ssh_agent_bind_hostkey(sock, ssh->kex->initial_hostkey, 1671 ssh->kex->session_id, ssh->kex->initial_sig, 1)) == 0) 1672 debug_f("bound agent to hostkey"); 1673 else 1674 debug2_fr(r, "ssh_agent_bind_hostkey"); 1675 1676 if (options.hpn_disabled) 1677 c = channel_new(ssh, "authentication agent connection", 1678 SSH_CHANNEL_OPEN, sock, sock, -1, 1679 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, 1680 "authentication agent connection", 1); 1681 else 1682 c = channel_new(ssh, "authentication agent connection", 1683 SSH_CHANNEL_OPEN, sock, sock, -1, 1684 options.hpn_buffer_size, options.hpn_buffer_size, 0, 1685 "authentication agent connection", 1); 1686 c->force_drain = 1; 1687 return c; 1688 } 1689 1690 char * 1691 client_request_tun_fwd(struct ssh *ssh, int tun_mode, 1692 int local_tun, int remote_tun, channel_open_fn *cb, void *cbctx) 1693 { 1694 Channel *c; 1695 int r, fd; 1696 char *ifname = NULL; 1697 1698 if (tun_mode == SSH_TUNMODE_NO) 1699 return 0; 1700 1701 debug("Requesting tun unit %d in mode %d", local_tun, tun_mode); 1702 1703 /* Open local tunnel device */ 1704 if ((fd = tun_open(local_tun, tun_mode, &ifname)) == -1) { 1705 error("Tunnel device open failed."); 1706 return NULL; 1707 } 1708 debug("Tunnel forwarding using interface %s", ifname); 1709 1710 if(options.hpn_disabled) 1711 c = channel_new(ssh, "tun", SSH_CHANNEL_OPENING, fd, fd, -1, 1712 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1); 1713 else 1714 c = channel_new(ssh, "tun", SSH_CHANNEL_OPENING, fd, fd, -1, 1715 options.hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1); 1716 c->datagram = 1; 1717 1718 if (cb != NULL) 1719 channel_register_open_confirm(ssh, c->self, cb, cbctx); 1720 1721 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1722 (r = sshpkt_put_cstring(ssh, "tun@openssh.com")) != 0 || 1723 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1724 (r = sshpkt_put_u32(ssh, c->local_window_max)) != 0 || 1725 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 1726 (r = sshpkt_put_u32(ssh, tun_mode)) != 0 || 1727 (r = sshpkt_put_u32(ssh, remote_tun)) != 0 || 1728 (r = sshpkt_send(ssh)) != 0) 1729 sshpkt_fatal(ssh, r, "%s: send reply", __func__); 1730 1731 return ifname; 1732 } 1733 1734 /* XXXX move to generic input handler */ 1735 static int 1736 client_input_channel_open(int type, u_int32_t seq, struct ssh *ssh) 1737 { 1738 Channel *c = NULL; 1739 char *ctype = NULL; 1740 int r; 1741 u_int rchan; 1742 size_t len; 1743 u_int rmaxpack, rwindow; 1744 1745 if ((r = sshpkt_get_cstring(ssh, &ctype, &len)) != 0 || 1746 (r = sshpkt_get_u32(ssh, &rchan)) != 0 || 1747 (r = sshpkt_get_u32(ssh, &rwindow)) != 0 || 1748 (r = sshpkt_get_u32(ssh, &rmaxpack)) != 0) 1749 goto out; 1750 1751 debug("client_input_channel_open: ctype %s rchan %d win %d max %d", 1752 ctype, rchan, rwindow, rmaxpack); 1753 1754 if (strcmp(ctype, "forwarded-tcpip") == 0) { 1755 c = client_request_forwarded_tcpip(ssh, ctype, rchan, rwindow, 1756 rmaxpack); 1757 } else if (strcmp(ctype, "forwarded-streamlocal@openssh.com") == 0) { 1758 c = client_request_forwarded_streamlocal(ssh, ctype, rchan); 1759 } else if (strcmp(ctype, "x11") == 0) { 1760 c = client_request_x11(ssh, ctype, rchan); 1761 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) { 1762 c = client_request_agent(ssh, ctype, rchan); 1763 } 1764 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) { 1765 debug3("proxied to downstream: %s", ctype); 1766 } else if (c != NULL) { 1767 debug("confirm %s", ctype); 1768 c->remote_id = rchan; 1769 c->have_remote_id = 1; 1770 c->remote_window = rwindow; 1771 c->remote_maxpacket = rmaxpack; 1772 if (c->type != SSH_CHANNEL_CONNECTING) { 1773 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 1774 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1775 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1776 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1777 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 1778 (r = sshpkt_send(ssh)) != 0) 1779 sshpkt_fatal(ssh, r, "%s: send reply", __func__); 1780 } 1781 } else { 1782 debug("failure %s", ctype); 1783 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || 1784 (r = sshpkt_put_u32(ssh, rchan)) != 0 || 1785 (r = sshpkt_put_u32(ssh, SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED)) != 0 || 1786 (r = sshpkt_put_cstring(ssh, "open failed")) != 0 || 1787 (r = sshpkt_put_cstring(ssh, "")) != 0 || 1788 (r = sshpkt_send(ssh)) != 0) 1789 sshpkt_fatal(ssh, r, "%s: send failure", __func__); 1790 } 1791 r = 0; 1792 out: 1793 free(ctype); 1794 return r; 1795 } 1796 1797 static int 1798 client_input_channel_req(int type, u_int32_t seq, struct ssh *ssh) 1799 { 1800 Channel *c = NULL; 1801 char *rtype = NULL; 1802 u_char reply; 1803 u_int id, exitval; 1804 int r, success = 0; 1805 1806 if ((r = sshpkt_get_u32(ssh, &id)) != 0) 1807 return r; 1808 if (id <= INT_MAX) 1809 c = channel_lookup(ssh, id); 1810 if (channel_proxy_upstream(c, type, seq, ssh)) 1811 return 0; 1812 if ((r = sshpkt_get_cstring(ssh, &rtype, NULL)) != 0 || 1813 (r = sshpkt_get_u8(ssh, &reply)) != 0) 1814 goto out; 1815 1816 debug("client_input_channel_req: channel %u rtype %s reply %d", 1817 id, rtype, reply); 1818 1819 if (c == NULL) { 1820 error("client_input_channel_req: channel %d: " 1821 "unknown channel", id); 1822 } else if (strcmp(rtype, "eow@openssh.com") == 0) { 1823 if ((r = sshpkt_get_end(ssh)) != 0) 1824 goto out; 1825 chan_rcvd_eow(ssh, c); 1826 } else if (strcmp(rtype, "exit-status") == 0) { 1827 if ((r = sshpkt_get_u32(ssh, &exitval)) != 0) 1828 goto out; 1829 if (c->ctl_chan != -1) { 1830 mux_exit_message(ssh, c, exitval); 1831 success = 1; 1832 } else if ((int)id == session_ident) { 1833 /* Record exit value of local session */ 1834 success = 1; 1835 exit_status = exitval; 1836 } else { 1837 /* Probably for a mux channel that has already closed */ 1838 debug_f("no sink for exit-status on channel %d", 1839 id); 1840 } 1841 if ((r = sshpkt_get_end(ssh)) != 0) 1842 goto out; 1843 } 1844 if (reply && c != NULL && !(c->flags & CHAN_CLOSE_SENT)) { 1845 if (!c->have_remote_id) 1846 fatal_f("channel %d: no remote_id", c->self); 1847 if ((r = sshpkt_start(ssh, success ? 1848 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE)) != 0 || 1849 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1850 (r = sshpkt_send(ssh)) != 0) 1851 sshpkt_fatal(ssh, r, "%s: send failure", __func__); 1852 } 1853 r = 0; 1854 out: 1855 free(rtype); 1856 return r; 1857 } 1858 1859 struct hostkeys_update_ctx { 1860 /* The hostname and (optionally) IP address string for the server */ 1861 char *host_str, *ip_str; 1862 1863 /* 1864 * Keys received from the server and a flag for each indicating 1865 * whether they already exist in known_hosts. 1866 * keys_match is filled in by hostkeys_find() and later (for new 1867 * keys) by client_global_hostkeys_prove_confirm(). 1868 */ 1869 struct sshkey **keys; 1870 u_int *keys_match; /* mask of HKF_MATCH_* from hostfile.h */ 1871 int *keys_verified; /* flag for new keys verified by server */ 1872 size_t nkeys, nnew, nincomplete; /* total, new keys, incomplete match */ 1873 1874 /* 1875 * Keys that are in known_hosts, but were not present in the update 1876 * from the server (i.e. scheduled to be deleted). 1877 * Filled in by hostkeys_find(). 1878 */ 1879 struct sshkey **old_keys; 1880 size_t nold; 1881 1882 /* Various special cases. */ 1883 int complex_hostspec; /* wildcard or manual pattern-list host name */ 1884 int ca_available; /* saw CA key for this host */ 1885 int old_key_seen; /* saw old key with other name/addr */ 1886 int other_name_seen; /* saw key with other name/addr */ 1887 }; 1888 1889 static void 1890 hostkeys_update_ctx_free(struct hostkeys_update_ctx *ctx) 1891 { 1892 size_t i; 1893 1894 if (ctx == NULL) 1895 return; 1896 for (i = 0; i < ctx->nkeys; i++) 1897 sshkey_free(ctx->keys[i]); 1898 free(ctx->keys); 1899 free(ctx->keys_match); 1900 free(ctx->keys_verified); 1901 for (i = 0; i < ctx->nold; i++) 1902 sshkey_free(ctx->old_keys[i]); 1903 free(ctx->old_keys); 1904 free(ctx->host_str); 1905 free(ctx->ip_str); 1906 free(ctx); 1907 } 1908 1909 /* 1910 * Returns non-zero if a known_hosts hostname list is not of a form that 1911 * can be handled by UpdateHostkeys. These include wildcard hostnames and 1912 * hostnames lists that do not follow the form host[,ip]. 1913 */ 1914 static int 1915 hostspec_is_complex(const char *hosts) 1916 { 1917 char *cp; 1918 1919 /* wildcard */ 1920 if (strchr(hosts, '*') != NULL || strchr(hosts, '?') != NULL) 1921 return 1; 1922 /* single host/ip = ok */ 1923 if ((cp = strchr(hosts, ',')) == NULL) 1924 return 0; 1925 /* more than two entries on the line */ 1926 if (strchr(cp + 1, ',') != NULL) 1927 return 1; 1928 /* XXX maybe parse cp+1 and ensure it is an IP? */ 1929 return 0; 1930 } 1931 1932 /* callback to search for ctx->keys in known_hosts */ 1933 static int 1934 hostkeys_find(struct hostkey_foreach_line *l, void *_ctx) 1935 { 1936 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 1937 size_t i; 1938 struct sshkey **tmp; 1939 1940 if (l->key == NULL) 1941 return 0; 1942 if (l->status != HKF_STATUS_MATCHED) { 1943 /* Record if one of the keys appears on a non-matching line */ 1944 for (i = 0; i < ctx->nkeys; i++) { 1945 if (sshkey_equal(l->key, ctx->keys[i])) { 1946 ctx->other_name_seen = 1; 1947 debug3_f("found %s key under different " 1948 "name/addr at %s:%ld", 1949 sshkey_ssh_name(ctx->keys[i]), 1950 l->path, l->linenum); 1951 return 0; 1952 } 1953 } 1954 return 0; 1955 } 1956 /* Don't proceed if revocation or CA markers are present */ 1957 /* XXX relax this */ 1958 if (l->marker != MRK_NONE) { 1959 debug3_f("hostkeys file %s:%ld has CA/revocation marker", 1960 l->path, l->linenum); 1961 ctx->complex_hostspec = 1; 1962 return 0; 1963 } 1964 1965 /* If CheckHostIP is enabled, then check for mismatched hostname/addr */ 1966 if (ctx->ip_str != NULL && strchr(l->hosts, ',') != NULL) { 1967 if ((l->match & HKF_MATCH_HOST) == 0) { 1968 /* Record if address matched a different hostname. */ 1969 ctx->other_name_seen = 1; 1970 debug3_f("found address %s against different hostname " 1971 "at %s:%ld", ctx->ip_str, l->path, l->linenum); 1972 return 0; 1973 } else if ((l->match & HKF_MATCH_IP) == 0) { 1974 /* Record if hostname matched a different address. */ 1975 ctx->other_name_seen = 1; 1976 debug3_f("found hostname %s against different address " 1977 "at %s:%ld", ctx->host_str, l->path, l->linenum); 1978 } 1979 } 1980 1981 /* 1982 * UpdateHostkeys is skipped for wildcard host names and hostnames 1983 * that contain more than two entries (ssh never writes these). 1984 */ 1985 if (hostspec_is_complex(l->hosts)) { 1986 debug3_f("hostkeys file %s:%ld complex host specification", 1987 l->path, l->linenum); 1988 ctx->complex_hostspec = 1; 1989 return 0; 1990 } 1991 1992 /* Mark off keys we've already seen for this host */ 1993 for (i = 0; i < ctx->nkeys; i++) { 1994 if (!sshkey_equal(l->key, ctx->keys[i])) 1995 continue; 1996 debug3_f("found %s key at %s:%ld", 1997 sshkey_ssh_name(ctx->keys[i]), l->path, l->linenum); 1998 ctx->keys_match[i] |= l->match; 1999 return 0; 2000 } 2001 /* This line contained a key that not offered by the server */ 2002 debug3_f("deprecated %s key at %s:%ld", sshkey_ssh_name(l->key), 2003 l->path, l->linenum); 2004 if ((tmp = recallocarray(ctx->old_keys, ctx->nold, ctx->nold + 1, 2005 sizeof(*ctx->old_keys))) == NULL) 2006 fatal_f("recallocarray failed nold = %zu", ctx->nold); 2007 ctx->old_keys = tmp; 2008 ctx->old_keys[ctx->nold++] = l->key; 2009 l->key = NULL; 2010 2011 return 0; 2012 } 2013 2014 /* callback to search for ctx->old_keys in known_hosts under other names */ 2015 static int 2016 hostkeys_check_old(struct hostkey_foreach_line *l, void *_ctx) 2017 { 2018 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 2019 size_t i; 2020 int hashed; 2021 2022 /* only care about lines that *don't* match the active host spec */ 2023 if (l->status == HKF_STATUS_MATCHED || l->key == NULL) 2024 return 0; 2025 2026 hashed = l->match & (HKF_MATCH_HOST_HASHED|HKF_MATCH_IP_HASHED); 2027 for (i = 0; i < ctx->nold; i++) { 2028 if (!sshkey_equal(l->key, ctx->old_keys[i])) 2029 continue; 2030 debug3_f("found deprecated %s key at %s:%ld as %s", 2031 sshkey_ssh_name(ctx->old_keys[i]), l->path, l->linenum, 2032 hashed ? "[HASHED]" : l->hosts); 2033 ctx->old_key_seen = 1; 2034 break; 2035 } 2036 return 0; 2037 } 2038 2039 /* 2040 * Check known_hosts files for deprecated keys under other names. Returns 0 2041 * on success or -1 on failure. Updates ctx->old_key_seen if deprecated keys 2042 * exist under names other than the active hostname/IP. 2043 */ 2044 static int 2045 check_old_keys_othernames(struct hostkeys_update_ctx *ctx) 2046 { 2047 size_t i; 2048 int r; 2049 2050 debug2_f("checking for %zu deprecated keys", ctx->nold); 2051 for (i = 0; i < options.num_user_hostfiles; i++) { 2052 debug3_f("searching %s for %s / %s", 2053 options.user_hostfiles[i], ctx->host_str, 2054 ctx->ip_str ? ctx->ip_str : "(none)"); 2055 if ((r = hostkeys_foreach(options.user_hostfiles[i], 2056 hostkeys_check_old, ctx, ctx->host_str, ctx->ip_str, 2057 HKF_WANT_PARSE_KEY, 0)) != 0) { 2058 if (r == SSH_ERR_SYSTEM_ERROR && errno == ENOENT) { 2059 debug_f("hostkeys file %s does not exist", 2060 options.user_hostfiles[i]); 2061 continue; 2062 } 2063 error_fr(r, "hostkeys_foreach failed for %s", 2064 options.user_hostfiles[i]); 2065 return -1; 2066 } 2067 } 2068 return 0; 2069 } 2070 2071 static void 2072 hostkey_change_preamble(LogLevel loglevel) 2073 { 2074 do_log2(loglevel, "The server has updated its host keys."); 2075 do_log2(loglevel, "These changes were verified by the server's " 2076 "existing trusted key."); 2077 } 2078 2079 static void 2080 update_known_hosts(struct hostkeys_update_ctx *ctx) 2081 { 2082 int r, was_raw = 0, first = 1; 2083 int asking = options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK; 2084 LogLevel loglevel = asking ? SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_VERBOSE; 2085 char *fp, *response; 2086 size_t i; 2087 struct stat sb; 2088 2089 for (i = 0; i < ctx->nkeys; i++) { 2090 if (!ctx->keys_verified[i]) 2091 continue; 2092 if ((fp = sshkey_fingerprint(ctx->keys[i], 2093 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 2094 fatal_f("sshkey_fingerprint failed"); 2095 if (first && asking) 2096 hostkey_change_preamble(loglevel); 2097 do_log2(loglevel, "Learned new hostkey: %s %s", 2098 sshkey_type(ctx->keys[i]), fp); 2099 first = 0; 2100 free(fp); 2101 } 2102 for (i = 0; i < ctx->nold; i++) { 2103 if ((fp = sshkey_fingerprint(ctx->old_keys[i], 2104 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 2105 fatal_f("sshkey_fingerprint failed"); 2106 if (first && asking) 2107 hostkey_change_preamble(loglevel); 2108 do_log2(loglevel, "Deprecating obsolete hostkey: %s %s", 2109 sshkey_type(ctx->old_keys[i]), fp); 2110 first = 0; 2111 free(fp); 2112 } 2113 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) { 2114 if (get_saved_tio() != NULL) { 2115 leave_raw_mode(1); 2116 was_raw = 1; 2117 } 2118 response = NULL; 2119 for (i = 0; !quit_pending && i < 3; i++) { 2120 free(response); 2121 response = read_passphrase("Accept updated hostkeys? " 2122 "(yes/no): ", RP_ECHO); 2123 if (response != NULL && strcasecmp(response, "yes") == 0) 2124 break; 2125 else if (quit_pending || response == NULL || 2126 strcasecmp(response, "no") == 0) { 2127 options.update_hostkeys = 0; 2128 break; 2129 } else { 2130 do_log2(loglevel, "Please enter " 2131 "\"yes\" or \"no\""); 2132 } 2133 } 2134 if (quit_pending || i >= 3 || response == NULL) 2135 options.update_hostkeys = 0; 2136 free(response); 2137 if (was_raw) 2138 enter_raw_mode(1); 2139 } 2140 if (options.update_hostkeys == 0) 2141 return; 2142 /* 2143 * Now that all the keys are verified, we can go ahead and replace 2144 * them in known_hosts (assuming SSH_UPDATE_HOSTKEYS_ASK didn't 2145 * cancel the operation). 2146 */ 2147 for (i = 0; i < options.num_user_hostfiles; i++) { 2148 /* 2149 * NB. keys are only added to hostfiles[0], for the rest we 2150 * just delete the hostname entries. 2151 */ 2152 if (stat(options.user_hostfiles[i], &sb) != 0) { 2153 if (errno == ENOENT) { 2154 debug_f("known hosts file %s does not " 2155 "exist", options.user_hostfiles[i]); 2156 } else { 2157 error_f("known hosts file %s " 2158 "inaccessible: %s", 2159 options.user_hostfiles[i], strerror(errno)); 2160 } 2161 continue; 2162 } 2163 if ((r = hostfile_replace_entries(options.user_hostfiles[i], 2164 ctx->host_str, ctx->ip_str, 2165 i == 0 ? ctx->keys : NULL, i == 0 ? ctx->nkeys : 0, 2166 options.hash_known_hosts, 0, 2167 options.fingerprint_hash)) != 0) { 2168 error_fr(r, "hostfile_replace_entries failed for %s", 2169 options.user_hostfiles[i]); 2170 } 2171 } 2172 } 2173 2174 static void 2175 client_global_hostkeys_prove_confirm(struct ssh *ssh, int type, 2176 u_int32_t seq, void *_ctx) 2177 { 2178 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 2179 size_t i, ndone; 2180 struct sshbuf *signdata; 2181 int r, plaintype; 2182 const u_char *sig; 2183 const char *rsa_kexalg = NULL; 2184 char *alg = NULL; 2185 size_t siglen; 2186 2187 if (ctx->nnew == 0) 2188 fatal_f("ctx->nnew == 0"); /* sanity */ 2189 if (type != SSH2_MSG_REQUEST_SUCCESS) { 2190 error("Server failed to confirm ownership of " 2191 "private host keys"); 2192 hostkeys_update_ctx_free(ctx); 2193 return; 2194 } 2195 if (sshkey_type_plain(sshkey_type_from_name( 2196 ssh->kex->hostkey_alg)) == KEY_RSA) 2197 rsa_kexalg = ssh->kex->hostkey_alg; 2198 if ((signdata = sshbuf_new()) == NULL) 2199 fatal_f("sshbuf_new failed"); 2200 /* 2201 * Expect a signature for each of the ctx->nnew private keys we 2202 * haven't seen before. They will be in the same order as the 2203 * ctx->keys where the corresponding ctx->keys_match[i] == 0. 2204 */ 2205 for (ndone = i = 0; i < ctx->nkeys; i++) { 2206 if (ctx->keys_match[i]) 2207 continue; 2208 plaintype = sshkey_type_plain(ctx->keys[i]->type); 2209 /* Prepare data to be signed: session ID, unique string, key */ 2210 sshbuf_reset(signdata); 2211 if ( (r = sshbuf_put_cstring(signdata, 2212 "hostkeys-prove-00@openssh.com")) != 0 || 2213 (r = sshbuf_put_stringb(signdata, 2214 ssh->kex->session_id)) != 0 || 2215 (r = sshkey_puts(ctx->keys[i], signdata)) != 0) 2216 fatal_fr(r, "compose signdata"); 2217 /* Extract and verify signature */ 2218 if ((r = sshpkt_get_string_direct(ssh, &sig, &siglen)) != 0) { 2219 error_fr(r, "parse sig"); 2220 goto out; 2221 } 2222 if ((r = sshkey_get_sigtype(sig, siglen, &alg)) != 0) { 2223 error_fr(r, "server gave unintelligible signature " 2224 "for %s key %zu", sshkey_type(ctx->keys[i]), i); 2225 goto out; 2226 } 2227 /* 2228 * Special case for RSA keys: if a RSA hostkey was negotiated, 2229 * then use its signature type for verification of RSA hostkey 2230 * proofs. Otherwise, accept only RSA-SHA256/512 signatures. 2231 */ 2232 if (plaintype == KEY_RSA && rsa_kexalg == NULL && 2233 match_pattern_list(alg, HOSTKEY_PROOF_RSA_ALGS, 0) != 1) { 2234 debug_f("server used untrusted RSA signature algorithm " 2235 "%s for key %zu, disregarding", alg, i); 2236 free(alg); 2237 /* zap the key from the list */ 2238 sshkey_free(ctx->keys[i]); 2239 ctx->keys[i] = NULL; 2240 ndone++; 2241 continue; 2242 } 2243 debug3_f("verify %s key %zu using sigalg %s", 2244 sshkey_type(ctx->keys[i]), i, alg); 2245 free(alg); 2246 if ((r = sshkey_verify(ctx->keys[i], sig, siglen, 2247 sshbuf_ptr(signdata), sshbuf_len(signdata), 2248 plaintype == KEY_RSA ? rsa_kexalg : NULL, 0, NULL)) != 0) { 2249 error_fr(r, "server gave bad signature for %s key %zu", 2250 sshkey_type(ctx->keys[i]), i); 2251 goto out; 2252 } 2253 /* Key is good. Mark it as 'seen' */ 2254 ctx->keys_verified[i] = 1; 2255 ndone++; 2256 } 2257 /* Shouldn't happen */ 2258 if (ndone != ctx->nnew) 2259 fatal_f("ndone != ctx->nnew (%zu / %zu)", ndone, ctx->nnew); 2260 if ((r = sshpkt_get_end(ssh)) != 0) { 2261 error_f("protocol error"); 2262 goto out; 2263 } 2264 2265 /* Make the edits to known_hosts */ 2266 update_known_hosts(ctx); 2267 out: 2268 hostkeys_update_ctx_free(ctx); 2269 hostkeys_update_complete = 1; 2270 client_repledge(); 2271 } 2272 2273 /* 2274 * Returns non-zero if the key is accepted by HostkeyAlgorithms. 2275 * Made slightly less trivial by the multiple RSA signature algorithm names. 2276 */ 2277 static int 2278 key_accepted_by_hostkeyalgs(const struct sshkey *key) 2279 { 2280 const char *ktype = sshkey_ssh_name(key); 2281 const char *hostkeyalgs = options.hostkeyalgorithms; 2282 2283 if (key == NULL || key->type == KEY_UNSPEC) 2284 return 0; 2285 if (key->type == KEY_RSA && 2286 (match_pattern_list("rsa-sha2-256", hostkeyalgs, 0) == 1 || 2287 match_pattern_list("rsa-sha2-512", hostkeyalgs, 0) == 1)) 2288 return 1; 2289 return match_pattern_list(ktype, hostkeyalgs, 0) == 1; 2290 } 2291 2292 /* 2293 * Handle hostkeys-00@openssh.com global request to inform the client of all 2294 * the server's hostkeys. The keys are checked against the user's 2295 * HostkeyAlgorithms preference before they are accepted. 2296 */ 2297 static int 2298 client_input_hostkeys(struct ssh *ssh) 2299 { 2300 const u_char *blob = NULL; 2301 size_t i, len = 0; 2302 struct sshbuf *buf = NULL; 2303 struct sshkey *key = NULL, **tmp; 2304 int r, prove_sent = 0; 2305 char *fp; 2306 static int hostkeys_seen = 0; /* XXX use struct ssh */ 2307 extern struct sockaddr_storage hostaddr; /* XXX from ssh.c */ 2308 struct hostkeys_update_ctx *ctx = NULL; 2309 u_int want; 2310 2311 if (hostkeys_seen) 2312 fatal_f("server already sent hostkeys"); 2313 if (!can_update_hostkeys()) 2314 return 1; 2315 hostkeys_seen = 1; 2316 2317 ctx = xcalloc(1, sizeof(*ctx)); 2318 while (ssh_packet_remaining(ssh) > 0) { 2319 sshkey_free(key); 2320 key = NULL; 2321 if ((r = sshpkt_get_string_direct(ssh, &blob, &len)) != 0) { 2322 error_fr(r, "parse key"); 2323 goto out; 2324 } 2325 if ((r = sshkey_from_blob(blob, len, &key)) != 0) { 2326 do_log2_fr(r, r == SSH_ERR_KEY_TYPE_UNKNOWN ? 2327 SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_ERROR, 2328 "convert key"); 2329 continue; 2330 } 2331 fp = sshkey_fingerprint(key, options.fingerprint_hash, 2332 SSH_FP_DEFAULT); 2333 debug3_f("received %s key %s", sshkey_type(key), fp); 2334 free(fp); 2335 2336 if (!key_accepted_by_hostkeyalgs(key)) { 2337 debug3_f("%s key not permitted by " 2338 "HostkeyAlgorithms", sshkey_ssh_name(key)); 2339 continue; 2340 } 2341 /* Skip certs */ 2342 if (sshkey_is_cert(key)) { 2343 debug3_f("%s key is a certificate; skipping", 2344 sshkey_ssh_name(key)); 2345 continue; 2346 } 2347 /* Ensure keys are unique */ 2348 for (i = 0; i < ctx->nkeys; i++) { 2349 if (sshkey_equal(key, ctx->keys[i])) { 2350 error_f("received duplicated %s host key", 2351 sshkey_ssh_name(key)); 2352 goto out; 2353 } 2354 } 2355 /* Key is good, record it */ 2356 if ((tmp = recallocarray(ctx->keys, ctx->nkeys, ctx->nkeys + 1, 2357 sizeof(*ctx->keys))) == NULL) 2358 fatal_f("recallocarray failed nkeys = %zu", 2359 ctx->nkeys); 2360 ctx->keys = tmp; 2361 ctx->keys[ctx->nkeys++] = key; 2362 key = NULL; 2363 } 2364 2365 if (ctx->nkeys == 0) { 2366 debug_f("server sent no hostkeys"); 2367 goto out; 2368 } 2369 2370 if ((ctx->keys_match = calloc(ctx->nkeys, 2371 sizeof(*ctx->keys_match))) == NULL || 2372 (ctx->keys_verified = calloc(ctx->nkeys, 2373 sizeof(*ctx->keys_verified))) == NULL) 2374 fatal_f("calloc failed"); 2375 2376 get_hostfile_hostname_ipaddr(host, 2377 options.check_host_ip ? (struct sockaddr *)&hostaddr : NULL, 2378 options.port, &ctx->host_str, 2379 options.check_host_ip ? &ctx->ip_str : NULL); 2380 2381 /* Find which keys we already know about. */ 2382 for (i = 0; i < options.num_user_hostfiles; i++) { 2383 debug_f("searching %s for %s / %s", 2384 options.user_hostfiles[i], ctx->host_str, 2385 ctx->ip_str ? ctx->ip_str : "(none)"); 2386 if ((r = hostkeys_foreach(options.user_hostfiles[i], 2387 hostkeys_find, ctx, ctx->host_str, ctx->ip_str, 2388 HKF_WANT_PARSE_KEY, 0)) != 0) { 2389 if (r == SSH_ERR_SYSTEM_ERROR && errno == ENOENT) { 2390 debug_f("hostkeys file %s does not exist", 2391 options.user_hostfiles[i]); 2392 continue; 2393 } 2394 error_fr(r, "hostkeys_foreach failed for %s", 2395 options.user_hostfiles[i]); 2396 goto out; 2397 } 2398 } 2399 2400 /* Figure out if we have any new keys to add */ 2401 ctx->nnew = ctx->nincomplete = 0; 2402 want = HKF_MATCH_HOST | ( options.check_host_ip ? HKF_MATCH_IP : 0); 2403 for (i = 0; i < ctx->nkeys; i++) { 2404 if (ctx->keys_match[i] == 0) 2405 ctx->nnew++; 2406 if ((ctx->keys_match[i] & want) != want) 2407 ctx->nincomplete++; 2408 } 2409 2410 debug3_f("%zu server keys: %zu new, %zu retained, " 2411 "%zu incomplete match. %zu to remove", ctx->nkeys, ctx->nnew, 2412 ctx->nkeys - ctx->nnew - ctx->nincomplete, 2413 ctx->nincomplete, ctx->nold); 2414 2415 if (ctx->nnew == 0 && ctx->nold == 0) { 2416 debug_f("no new or deprecated keys from server"); 2417 goto out; 2418 } 2419 2420 /* Various reasons why we cannot proceed with the update */ 2421 if (ctx->complex_hostspec) { 2422 debug_f("CA/revocation marker, manual host list or wildcard " 2423 "host pattern found, skipping UserKnownHostsFile update"); 2424 goto out; 2425 } 2426 if (ctx->other_name_seen) { 2427 debug_f("host key found matching a different name/address, " 2428 "skipping UserKnownHostsFile update"); 2429 goto out; 2430 } 2431 /* 2432 * If removing keys, check whether they appear under different 2433 * names/addresses and refuse to proceed if they do. This avoids 2434 * cases such as hosts with multiple names becoming inconsistent 2435 * with regards to CheckHostIP entries. 2436 * XXX UpdateHostkeys=force to override this (and other) checks? 2437 */ 2438 if (ctx->nold != 0) { 2439 if (check_old_keys_othernames(ctx) != 0) 2440 goto out; /* error already logged */ 2441 if (ctx->old_key_seen) { 2442 debug_f("key(s) for %s%s%s exist under other names; " 2443 "skipping UserKnownHostsFile update", 2444 ctx->host_str, ctx->ip_str == NULL ? "" : ",", 2445 ctx->ip_str == NULL ? "" : ctx->ip_str); 2446 goto out; 2447 } 2448 } 2449 2450 if (ctx->nnew == 0) { 2451 /* 2452 * We have some keys to remove or fix matching for. 2453 * We can proceed to do this without requiring a fresh proof 2454 * from the server. 2455 */ 2456 update_known_hosts(ctx); 2457 goto out; 2458 } 2459 /* 2460 * We have received previously-unseen keys from the server. 2461 * Ask the server to confirm ownership of the private halves. 2462 */ 2463 debug3_f("asking server to prove ownership for %zu keys", ctx->nnew); 2464 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 2465 (r = sshpkt_put_cstring(ssh, 2466 "hostkeys-prove-00@openssh.com")) != 0 || 2467 (r = sshpkt_put_u8(ssh, 1)) != 0) /* bool: want reply */ 2468 fatal_fr(r, "prepare hostkeys-prove"); 2469 if ((buf = sshbuf_new()) == NULL) 2470 fatal_f("sshbuf_new"); 2471 for (i = 0; i < ctx->nkeys; i++) { 2472 if (ctx->keys_match[i]) 2473 continue; 2474 sshbuf_reset(buf); 2475 if ((r = sshkey_putb(ctx->keys[i], buf)) != 0 || 2476 (r = sshpkt_put_stringb(ssh, buf)) != 0) 2477 fatal_fr(r, "assemble hostkeys-prove"); 2478 } 2479 if ((r = sshpkt_send(ssh)) != 0) 2480 fatal_fr(r, "send hostkeys-prove"); 2481 client_register_global_confirm( 2482 client_global_hostkeys_prove_confirm, ctx); 2483 ctx = NULL; /* will be freed in callback */ 2484 prove_sent = 1; 2485 2486 /* Success */ 2487 out: 2488 hostkeys_update_ctx_free(ctx); 2489 sshkey_free(key); 2490 sshbuf_free(buf); 2491 if (!prove_sent) { 2492 /* UpdateHostkeys handling completed */ 2493 hostkeys_update_complete = 1; 2494 client_repledge(); 2495 } 2496 /* 2497 * NB. Return success for all cases. The server doesn't need to know 2498 * what the client does with its hosts file. 2499 */ 2500 return 1; 2501 } 2502 2503 static int 2504 client_input_global_request(int type, u_int32_t seq, struct ssh *ssh) 2505 { 2506 char *rtype; 2507 u_char want_reply; 2508 int r, success = 0; 2509 2510 if ((r = sshpkt_get_cstring(ssh, &rtype, NULL)) != 0 || 2511 (r = sshpkt_get_u8(ssh, &want_reply)) != 0) 2512 goto out; 2513 debug("client_input_global_request: rtype %s want_reply %d", 2514 rtype, want_reply); 2515 if (strcmp(rtype, "hostkeys-00@openssh.com") == 0) 2516 success = client_input_hostkeys(ssh); 2517 if (want_reply) { 2518 if ((r = sshpkt_start(ssh, success ? SSH2_MSG_REQUEST_SUCCESS : 2519 SSH2_MSG_REQUEST_FAILURE)) != 0 || 2520 (r = sshpkt_send(ssh)) != 0 || 2521 (r = ssh_packet_write_wait(ssh)) != 0) 2522 goto out; 2523 } 2524 r = 0; 2525 out: 2526 free(rtype); 2527 return r; 2528 } 2529 2530 static void 2531 client_send_env(struct ssh *ssh, int id, const char *name, const char *val) 2532 { 2533 int r; 2534 2535 debug("channel %d: setting env %s = \"%s\"", id, name, val); 2536 channel_request_start(ssh, id, "env", 0); 2537 if ((r = sshpkt_put_cstring(ssh, name)) != 0 || 2538 (r = sshpkt_put_cstring(ssh, val)) != 0 || 2539 (r = sshpkt_send(ssh)) != 0) 2540 fatal_fr(r, "send setenv"); 2541 } 2542 2543 void 2544 client_session2_setup(struct ssh *ssh, int id, int want_tty, int want_subsystem, 2545 const char *term, struct termios *tiop, int in_fd, struct sshbuf *cmd, 2546 char **env) 2547 { 2548 size_t i, j, len; 2549 int matched, r; 2550 char *name, *val; 2551 Channel *c = NULL; 2552 2553 debug2_f("id %d", id); 2554 2555 if ((c = channel_lookup(ssh, id)) == NULL) 2556 fatal_f("channel %d: unknown channel", id); 2557 2558 ssh_packet_set_interactive(ssh, want_tty, 2559 options.ip_qos_interactive, options.ip_qos_bulk); 2560 2561 if (want_tty) { 2562 struct winsize ws; 2563 2564 /* Store window size in the packet. */ 2565 if (ioctl(in_fd, TIOCGWINSZ, &ws) == -1) 2566 memset(&ws, 0, sizeof(ws)); 2567 2568 channel_request_start(ssh, id, "pty-req", 1); 2569 client_expect_confirm(ssh, id, "PTY allocation", CONFIRM_TTY); 2570 if ((r = sshpkt_put_cstring(ssh, term != NULL ? term : "")) 2571 != 0 || 2572 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || 2573 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || 2574 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || 2575 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0) 2576 fatal_fr(r, "build pty-req"); 2577 if (tiop == NULL) 2578 tiop = get_saved_tio(); 2579 ssh_tty_make_modes(ssh, -1, tiop); 2580 if ((r = sshpkt_send(ssh)) != 0) 2581 fatal_fr(r, "send pty-req"); 2582 /* XXX wait for reply */ 2583 c->client_tty = 1; 2584 } 2585 2586 /* Transfer any environment variables from client to server */ 2587 if (options.num_send_env != 0 && env != NULL) { 2588 debug("Sending environment."); 2589 for (i = 0; env[i] != NULL; i++) { 2590 /* Split */ 2591 name = xstrdup(env[i]); 2592 if ((val = strchr(name, '=')) == NULL) { 2593 free(name); 2594 continue; 2595 } 2596 *val++ = '\0'; 2597 2598 matched = 0; 2599 for (j = 0; j < options.num_send_env; j++) { 2600 if (match_pattern(name, options.send_env[j])) { 2601 matched = 1; 2602 break; 2603 } 2604 } 2605 if (!matched) { 2606 debug3("Ignored env %s", name); 2607 free(name); 2608 continue; 2609 } 2610 client_send_env(ssh, id, name, val); 2611 free(name); 2612 } 2613 } 2614 for (i = 0; i < options.num_setenv; i++) { 2615 /* Split */ 2616 name = xstrdup(options.setenv[i]); 2617 if ((val = strchr(name, '=')) == NULL) { 2618 free(name); 2619 continue; 2620 } 2621 *val++ = '\0'; 2622 client_send_env(ssh, id, name, val); 2623 free(name); 2624 } 2625 2626 len = sshbuf_len(cmd); 2627 if (len > 0) { 2628 if (len > 900) 2629 len = 900; 2630 if (want_subsystem) { 2631 debug("Sending subsystem: %.*s", 2632 (int)len, (const u_char*)sshbuf_ptr(cmd)); 2633 channel_request_start(ssh, id, "subsystem", 1); 2634 client_expect_confirm(ssh, id, "subsystem", 2635 CONFIRM_CLOSE); 2636 } else { 2637 debug("Sending command: %.*s", 2638 (int)len, (const u_char*)sshbuf_ptr(cmd)); 2639 channel_request_start(ssh, id, "exec", 1); 2640 client_expect_confirm(ssh, id, "exec", CONFIRM_CLOSE); 2641 } 2642 if ((r = sshpkt_put_stringb(ssh, cmd)) != 0 || 2643 (r = sshpkt_send(ssh)) != 0) 2644 fatal_fr(r, "send command"); 2645 } else { 2646 channel_request_start(ssh, id, "shell", 1); 2647 client_expect_confirm(ssh, id, "shell", CONFIRM_CLOSE); 2648 if ((r = sshpkt_send(ssh)) != 0) 2649 fatal_fr(r, "send shell"); 2650 } 2651 2652 session_setup_complete = 1; 2653 client_repledge(); 2654 } 2655 2656 static void 2657 client_init_dispatch(struct ssh *ssh) 2658 { 2659 ssh_dispatch_init(ssh, &dispatch_protocol_error); 2660 2661 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); 2662 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_DATA, &channel_input_data); 2663 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); 2664 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); 2665 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open); 2666 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 2667 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 2668 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req); 2669 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); 2670 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm); 2671 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm); 2672 ssh_dispatch_set(ssh, SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request); 2673 2674 /* rekeying */ 2675 ssh_dispatch_set(ssh, SSH2_MSG_KEXINIT, &kex_input_kexinit); 2676 2677 /* global request reply messages */ 2678 ssh_dispatch_set(ssh, SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply); 2679 ssh_dispatch_set(ssh, SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply); 2680 } 2681 2682 void 2683 client_stop_mux(void) 2684 { 2685 if (options.control_path != NULL && muxserver_sock != -1) 2686 unlink(options.control_path); 2687 /* 2688 * If we are in persist mode, or don't have a shell, signal that we 2689 * should close when all active channels are closed. 2690 */ 2691 if (options.control_persist || options.session_type == SESSION_TYPE_NONE) { 2692 session_closed = 1; 2693 setproctitle("[stopped mux]"); 2694 } 2695 } 2696 2697 /* client specific fatal cleanup */ 2698 void 2699 cleanup_exit(int i) 2700 { 2701 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 2702 if (options.control_path != NULL && muxserver_sock != -1) 2703 unlink(options.control_path); 2704 ssh_kill_proxy_command(); 2705 _exit(i); 2706 } 2707