1 /* $OpenBSD: clientloop.c,v 1.407 2024/05/17 06:42:04 jsg Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * The main loop for the interactive session (client side). 7 * 8 * As far as I am concerned, the code I have written for this software 9 * can be used freely for any purpose. Any derived versions of this 10 * software must be clearly marked as such, and if the derived work is 11 * incompatible with the protocol description in the RFC file, it must be 12 * called by a name other than "ssh" or "Secure Shell". 13 * 14 * 15 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 16 * 17 * Redistribution and use in source and binary forms, with or without 18 * modification, are permitted provided that the following conditions 19 * are met: 20 * 1. Redistributions of source code must retain the above copyright 21 * notice, this list of conditions and the following disclaimer. 22 * 2. Redistributions in binary form must reproduce the above copyright 23 * notice, this list of conditions and the following disclaimer in the 24 * documentation and/or other materials provided with the distribution. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 27 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 28 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 29 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 30 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 31 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 35 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 36 * 37 * 38 * SSH2 support added by Markus Friedl. 39 * Copyright (c) 1999, 2000, 2001 Markus Friedl. All rights reserved. 40 * 41 * Redistribution and use in source and binary forms, with or without 42 * modification, are permitted provided that the following conditions 43 * are met: 44 * 1. Redistributions of source code must retain the above copyright 45 * notice, this list of conditions and the following disclaimer. 46 * 2. Redistributions in binary form must reproduce the above copyright 47 * notice, this list of conditions and the following disclaimer in the 48 * documentation and/or other materials provided with the distribution. 49 * 50 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 51 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 52 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 53 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 54 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 55 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 56 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 57 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 58 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 59 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 60 */ 61 62 63 #include <sys/types.h> 64 #include <sys/ioctl.h> 65 #include <sys/stat.h> 66 #include <sys/socket.h> 67 #include <sys/time.h> 68 #include <sys/queue.h> 69 70 #include <ctype.h> 71 #include <errno.h> 72 #include <paths.h> 73 #include <poll.h> 74 #include <signal.h> 75 #include <stdio.h> 76 #include <stdlib.h> 77 #include <string.h> 78 #include <stdarg.h> 79 #include <termios.h> 80 #include <pwd.h> 81 #include <unistd.h> 82 #include <limits.h> 83 84 #include "xmalloc.h" 85 #include "ssh.h" 86 #include "ssh2.h" 87 #include "packet.h" 88 #include "sshbuf.h" 89 #include "compat.h" 90 #include "channels.h" 91 #include "dispatch.h" 92 #include "sshkey.h" 93 #include "cipher.h" 94 #include "kex.h" 95 #include "myproposal.h" 96 #include "log.h" 97 #include "misc.h" 98 #include "readconf.h" 99 #include "clientloop.h" 100 #include "sshconnect.h" 101 #include "authfd.h" 102 #include "atomicio.h" 103 #include "sshpty.h" 104 #include "match.h" 105 #include "msg.h" 106 #include "ssherr.h" 107 #include "hostfile.h" 108 109 /* Permitted RSA signature algorithms for UpdateHostkeys proofs */ 110 #define HOSTKEY_PROOF_RSA_ALGS "rsa-sha2-512,rsa-sha2-256" 111 112 /* Uncertainty (in percent) of keystroke timing intervals */ 113 #define SSH_KEYSTROKE_TIMING_FUZZ 10 114 115 /* import options */ 116 extern Options options; 117 118 /* Control socket */ 119 extern int muxserver_sock; /* XXX use mux_client_cleanup() instead */ 120 121 /* 122 * Name of the host we are connecting to. This is the name given on the 123 * command line, or the Hostname specified for the user-supplied name in a 124 * configuration file. 125 */ 126 extern char *host; 127 128 /* 129 * If this field is not NULL, the ForwardAgent socket is this path and different 130 * instead of SSH_AUTH_SOCK. 131 */ 132 extern char *forward_agent_sock_path; 133 134 /* 135 * Flag to indicate that we have received a window change signal which has 136 * not yet been processed. This will cause a message indicating the new 137 * window size to be sent to the server a little later. This is volatile 138 * because this is updated in a signal handler. 139 */ 140 static volatile sig_atomic_t received_window_change_signal = 0; 141 static volatile sig_atomic_t received_signal = 0; 142 143 /* Time when backgrounded control master using ControlPersist should exit */ 144 static time_t control_persist_exit_time = 0; 145 146 /* Common data for the client loop code. */ 147 volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */ 148 static int last_was_cr; /* Last character was a newline. */ 149 static int exit_status; /* Used to store the command exit status. */ 150 static int connection_in; /* Connection to server (input). */ 151 static int connection_out; /* Connection to server (output). */ 152 static int need_rekeying; /* Set to non-zero if rekeying is requested. */ 153 static int session_closed; /* In SSH2: login session closed. */ 154 static time_t x11_refuse_time; /* If >0, refuse x11 opens after this time. */ 155 static time_t server_alive_time; /* Time to do server_alive_check */ 156 static int hostkeys_update_complete; 157 static int session_setup_complete; 158 159 static void client_init_dispatch(struct ssh *ssh); 160 int session_ident = -1; 161 162 /* Track escape per proto2 channel */ 163 struct escape_filter_ctx { 164 int escape_pending; 165 int escape_char; 166 }; 167 168 /* Context for channel confirmation replies */ 169 struct channel_reply_ctx { 170 const char *request_type; 171 int id; 172 enum confirm_action action; 173 }; 174 175 /* Global request success/failure callbacks */ 176 /* XXX move to struct ssh? */ 177 struct global_confirm { 178 TAILQ_ENTRY(global_confirm) entry; 179 global_confirm_cb *cb; 180 void *ctx; 181 int ref_count; 182 }; 183 TAILQ_HEAD(global_confirms, global_confirm); 184 static struct global_confirms global_confirms = 185 TAILQ_HEAD_INITIALIZER(global_confirms); 186 187 static void quit_message(const char *fmt, ...) 188 __attribute__((__format__ (printf, 1, 2))); 189 190 static void 191 quit_message(const char *fmt, ...) 192 { 193 char *msg, *fmt2; 194 va_list args; 195 xasprintf(&fmt2, "%s\r\n", fmt); 196 197 va_start(args, fmt); 198 xvasprintf(&msg, fmt2, args); 199 va_end(args); 200 201 (void)atomicio(vwrite, STDERR_FILENO, msg, strlen(msg)); 202 free(msg); 203 free(fmt2); 204 205 quit_pending = 1; 206 } 207 208 /* 209 * Signal handler for the window change signal (SIGWINCH). This just sets a 210 * flag indicating that the window has changed. 211 */ 212 static void 213 window_change_handler(int sig) 214 { 215 received_window_change_signal = 1; 216 } 217 218 /* 219 * Signal handler for signals that cause the program to terminate. These 220 * signals must be trapped to restore terminal modes. 221 */ 222 static void 223 signal_handler(int sig) 224 { 225 received_signal = sig; 226 quit_pending = 1; 227 } 228 229 /* 230 * Sets control_persist_exit_time to the absolute time when the 231 * backgrounded control master should exit due to expiry of the 232 * ControlPersist timeout. Sets it to 0 if we are not a backgrounded 233 * control master process, or if there is no ControlPersist timeout. 234 */ 235 static void 236 set_control_persist_exit_time(struct ssh *ssh) 237 { 238 if (muxserver_sock == -1 || !options.control_persist 239 || options.control_persist_timeout == 0) { 240 /* not using a ControlPersist timeout */ 241 control_persist_exit_time = 0; 242 } else if (channel_still_open(ssh)) { 243 /* some client connections are still open */ 244 if (control_persist_exit_time > 0) 245 debug2_f("cancel scheduled exit"); 246 control_persist_exit_time = 0; 247 } else if (control_persist_exit_time <= 0) { 248 /* a client connection has recently closed */ 249 control_persist_exit_time = monotime() + 250 (time_t)options.control_persist_timeout; 251 debug2_f("schedule exit in %d seconds", 252 options.control_persist_timeout); 253 } 254 /* else we are already counting down to the timeout */ 255 } 256 257 #define SSH_X11_VALID_DISPLAY_CHARS ":/.-_" 258 static int 259 client_x11_display_valid(const char *display) 260 { 261 size_t i, dlen; 262 263 if (display == NULL) 264 return 0; 265 266 dlen = strlen(display); 267 for (i = 0; i < dlen; i++) { 268 if (!isalnum((u_char)display[i]) && 269 strchr(SSH_X11_VALID_DISPLAY_CHARS, display[i]) == NULL) { 270 debug("Invalid character '%c' in DISPLAY", display[i]); 271 return 0; 272 } 273 } 274 return 1; 275 } 276 277 #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1" 278 #define X11_TIMEOUT_SLACK 60 279 int 280 client_x11_get_proto(struct ssh *ssh, const char *display, 281 const char *xauth_path, u_int trusted, u_int timeout, 282 char **_proto, char **_data) 283 { 284 char *cmd, line[512], xdisplay[512]; 285 char xauthfile[PATH_MAX], xauthdir[PATH_MAX]; 286 static char proto[512], data[512]; 287 FILE *f; 288 int got_data = 0, generated = 0, do_unlink = 0, r; 289 struct stat st; 290 u_int now, x11_timeout_real; 291 292 *_proto = proto; 293 *_data = data; 294 proto[0] = data[0] = xauthfile[0] = xauthdir[0] = '\0'; 295 296 if (!client_x11_display_valid(display)) { 297 if (display != NULL) 298 logit("DISPLAY \"%s\" invalid; disabling X11 forwarding", 299 display); 300 return -1; 301 } 302 if (xauth_path != NULL && stat(xauth_path, &st) == -1) { 303 debug("No xauth program."); 304 xauth_path = NULL; 305 } 306 307 if (xauth_path != NULL) { 308 /* 309 * Handle FamilyLocal case where $DISPLAY does 310 * not match an authorization entry. For this we 311 * just try "xauth list unix:displaynum.screennum". 312 * XXX: "localhost" match to determine FamilyLocal 313 * is not perfect. 314 */ 315 if (strncmp(display, "localhost:", 10) == 0) { 316 if ((r = snprintf(xdisplay, sizeof(xdisplay), "unix:%s", 317 display + 10)) < 0 || 318 (size_t)r >= sizeof(xdisplay)) { 319 error_f("display name too long"); 320 return -1; 321 } 322 display = xdisplay; 323 } 324 if (trusted == 0) { 325 /* 326 * Generate an untrusted X11 auth cookie. 327 * 328 * The authentication cookie should briefly outlive 329 * ssh's willingness to forward X11 connections to 330 * avoid nasty fail-open behaviour in the X server. 331 */ 332 mktemp_proto(xauthdir, sizeof(xauthdir)); 333 if (mkdtemp(xauthdir) == NULL) { 334 error_f("mkdtemp: %s", strerror(errno)); 335 return -1; 336 } 337 do_unlink = 1; 338 if ((r = snprintf(xauthfile, sizeof(xauthfile), 339 "%s/xauthfile", xauthdir)) < 0 || 340 (size_t)r >= sizeof(xauthfile)) { 341 error_f("xauthfile path too long"); 342 rmdir(xauthdir); 343 return -1; 344 } 345 346 if (timeout == 0) { 347 /* auth doesn't time out */ 348 xasprintf(&cmd, "%s -f %s generate %s %s " 349 "untrusted 2>%s", 350 xauth_path, xauthfile, display, 351 SSH_X11_PROTO, _PATH_DEVNULL); 352 } else { 353 /* Add some slack to requested expiry */ 354 if (timeout < UINT_MAX - X11_TIMEOUT_SLACK) 355 x11_timeout_real = timeout + 356 X11_TIMEOUT_SLACK; 357 else { 358 /* Don't overflow on long timeouts */ 359 x11_timeout_real = UINT_MAX; 360 } 361 xasprintf(&cmd, "%s -f %s generate %s %s " 362 "untrusted timeout %u 2>%s", 363 xauth_path, xauthfile, display, 364 SSH_X11_PROTO, x11_timeout_real, 365 _PATH_DEVNULL); 366 } 367 debug2_f("xauth command: %s", cmd); 368 369 if (timeout != 0 && x11_refuse_time == 0) { 370 now = monotime() + 1; 371 if (SSH_TIME_T_MAX - timeout < now) 372 x11_refuse_time = SSH_TIME_T_MAX; 373 else 374 x11_refuse_time = now + timeout; 375 channel_set_x11_refuse_time(ssh, 376 x11_refuse_time); 377 } 378 if (system(cmd) == 0) 379 generated = 1; 380 free(cmd); 381 } 382 383 /* 384 * When in untrusted mode, we read the cookie only if it was 385 * successfully generated as an untrusted one in the step 386 * above. 387 */ 388 if (trusted || generated) { 389 xasprintf(&cmd, 390 "%s %s%s list %s 2>" _PATH_DEVNULL, 391 xauth_path, 392 generated ? "-f " : "" , 393 generated ? xauthfile : "", 394 display); 395 debug2("x11_get_proto: %s", cmd); 396 f = popen(cmd, "r"); 397 if (f && fgets(line, sizeof(line), f) && 398 sscanf(line, "%*s %511s %511s", proto, data) == 2) 399 got_data = 1; 400 if (f) 401 pclose(f); 402 free(cmd); 403 } 404 } 405 406 if (do_unlink) { 407 unlink(xauthfile); 408 rmdir(xauthdir); 409 } 410 411 /* Don't fall back to fake X11 data for untrusted forwarding */ 412 if (!trusted && !got_data) { 413 error("Warning: untrusted X11 forwarding setup failed: " 414 "xauth key data not generated"); 415 return -1; 416 } 417 418 /* 419 * If we didn't get authentication data, just make up some 420 * data. The forwarding code will check the validity of the 421 * response anyway, and substitute this data. The X11 422 * server, however, will ignore this fake data and use 423 * whatever authentication mechanisms it was using otherwise 424 * for the local connection. 425 */ 426 if (!got_data) { 427 u_int8_t rnd[16]; 428 u_int i; 429 430 logit("Warning: No xauth data; " 431 "using fake authentication data for X11 forwarding."); 432 strlcpy(proto, SSH_X11_PROTO, sizeof proto); 433 arc4random_buf(rnd, sizeof(rnd)); 434 for (i = 0; i < sizeof(rnd); i++) { 435 snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", 436 rnd[i]); 437 } 438 } 439 440 return 0; 441 } 442 443 /* 444 * Checks if the client window has changed, and sends a packet about it to 445 * the server if so. The actual change is detected elsewhere (by a software 446 * interrupt on Unix); this just checks the flag and sends a message if 447 * appropriate. 448 */ 449 450 static void 451 client_check_window_change(struct ssh *ssh) 452 { 453 if (!received_window_change_signal) 454 return; 455 received_window_change_signal = 0; 456 debug2_f("changed"); 457 channel_send_window_changes(ssh); 458 } 459 460 static int 461 client_global_request_reply(int type, u_int32_t seq, struct ssh *ssh) 462 { 463 struct global_confirm *gc; 464 465 if ((gc = TAILQ_FIRST(&global_confirms)) == NULL) 466 return 0; 467 if (gc->cb != NULL) 468 gc->cb(ssh, type, seq, gc->ctx); 469 if (--gc->ref_count <= 0) { 470 TAILQ_REMOVE(&global_confirms, gc, entry); 471 freezero(gc, sizeof(*gc)); 472 } 473 474 ssh_packet_set_alive_timeouts(ssh, 0); 475 return 0; 476 } 477 478 static void 479 schedule_server_alive_check(void) 480 { 481 if (options.server_alive_interval > 0) 482 server_alive_time = monotime() + options.server_alive_interval; 483 } 484 485 static void 486 server_alive_check(struct ssh *ssh) 487 { 488 int r; 489 490 if (ssh_packet_inc_alive_timeouts(ssh) > options.server_alive_count_max) { 491 logit("Timeout, server %s not responding.", host); 492 cleanup_exit(255); 493 } 494 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 495 (r = sshpkt_put_cstring(ssh, "keepalive@openssh.com")) != 0 || 496 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* boolean: want reply */ 497 (r = sshpkt_send(ssh)) != 0) 498 fatal_fr(r, "send packet"); 499 /* Insert an empty placeholder to maintain ordering */ 500 client_register_global_confirm(NULL, NULL); 501 schedule_server_alive_check(); 502 } 503 504 /* Try to send a dummy keystroke */ 505 static int 506 send_chaff(struct ssh *ssh) 507 { 508 int r; 509 510 if (ssh->kex == NULL || (ssh->kex->flags & KEX_HAS_PING) == 0) 511 return 0; 512 /* XXX probabilistically send chaff? */ 513 /* 514 * a SSH2_MSG_CHANNEL_DATA payload is 9 bytes: 515 * 4 bytes channel ID + 4 bytes string length + 1 byte string data 516 * simulate that here. 517 */ 518 if ((r = sshpkt_start(ssh, SSH2_MSG_PING)) != 0 || 519 (r = sshpkt_put_cstring(ssh, "PING!")) != 0 || 520 (r = sshpkt_send(ssh)) != 0) 521 fatal_fr(r, "send packet"); 522 return 1; 523 } 524 525 /* Sets the next interval to send a keystroke or chaff packet */ 526 static void 527 set_next_interval(const struct timespec *now, struct timespec *next_interval, 528 u_int interval_ms, int starting) 529 { 530 struct timespec tmp; 531 long long interval_ns, fuzz_ns; 532 static long long rate_fuzz; 533 534 interval_ns = interval_ms * (1000LL * 1000); 535 fuzz_ns = (interval_ns * SSH_KEYSTROKE_TIMING_FUZZ) / 100; 536 /* Center fuzz around requested interval */ 537 if (fuzz_ns > INT_MAX) 538 fuzz_ns = INT_MAX; 539 if (fuzz_ns > interval_ns) { 540 /* Shouldn't happen */ 541 fatal_f("internal error: fuzz %u%% %lldns > interval %lldns", 542 SSH_KEYSTROKE_TIMING_FUZZ, fuzz_ns, interval_ns); 543 } 544 /* 545 * Randomise the keystroke/chaff intervals in two ways: 546 * 1. Each interval has some random jitter applied to make the 547 * interval-to-interval time unpredictable. 548 * 2. The overall interval rate is also randomly perturbed for each 549 * chaffing session to make the average rate unpredictable. 550 */ 551 if (starting) 552 rate_fuzz = arc4random_uniform(fuzz_ns); 553 interval_ns -= fuzz_ns; 554 interval_ns += arc4random_uniform(fuzz_ns) + rate_fuzz; 555 556 tmp.tv_sec = interval_ns / (1000 * 1000 * 1000); 557 tmp.tv_nsec = interval_ns % (1000 * 1000 * 1000); 558 559 timespecadd(now, &tmp, next_interval); 560 } 561 562 /* 563 * Performs keystroke timing obfuscation. Returns non-zero if the 564 * output fd should be polled. 565 */ 566 static int 567 obfuscate_keystroke_timing(struct ssh *ssh, struct timespec *timeout, 568 int channel_did_enqueue) 569 { 570 static int active; 571 static struct timespec next_interval, chaff_until; 572 struct timespec now, tmp; 573 int just_started = 0, had_keystroke = 0; 574 static unsigned long long nchaff; 575 char *stop_reason = NULL; 576 long long n; 577 578 monotime_ts(&now); 579 580 if (options.obscure_keystroke_timing_interval <= 0) 581 return 1; /* disabled in config */ 582 583 if (!channel_tty_open(ssh) || quit_pending) { 584 /* Stop if no channels left of we're waiting for one to close */ 585 stop_reason = "no active channels"; 586 } else if (ssh_packet_is_rekeying(ssh)) { 587 /* Stop if we're rekeying */ 588 stop_reason = "rekeying started"; 589 } else if (!ssh_packet_interactive_data_to_write(ssh) && 590 ssh_packet_have_data_to_write(ssh)) { 591 /* Stop if the output buffer has more than a few keystrokes */ 592 stop_reason = "output buffer filling"; 593 } else if (active && channel_did_enqueue && 594 ssh_packet_have_data_to_write(ssh)) { 595 /* Still in active mode and have a keystroke queued. */ 596 had_keystroke = 1; 597 } else if (active) { 598 if (timespeccmp(&now, &chaff_until, >=)) { 599 /* Stop if there have been no keystrokes for a while */ 600 stop_reason = "chaff time expired"; 601 } else if (timespeccmp(&now, &next_interval, >=)) { 602 /* Otherwise if we were due to send, then send chaff */ 603 if (send_chaff(ssh)) 604 nchaff++; 605 } 606 } 607 608 if (stop_reason != NULL) { 609 if (active) { 610 debug3_f("stopping: %s (%llu chaff packets sent)", 611 stop_reason, nchaff); 612 active = 0; 613 } 614 return 1; 615 } 616 617 /* 618 * If we're in interactive mode, and only have a small amount 619 * of outbound data, then we assume that the user is typing 620 * interactively. In this case, start quantising outbound packets to 621 * fixed time intervals to hide inter-keystroke timing. 622 */ 623 if (!active && ssh_packet_interactive_data_to_write(ssh) && 624 channel_did_enqueue && ssh_packet_have_data_to_write(ssh)) { 625 debug3_f("starting: interval ~%dms", 626 options.obscure_keystroke_timing_interval); 627 just_started = had_keystroke = active = 1; 628 nchaff = 0; 629 set_next_interval(&now, &next_interval, 630 options.obscure_keystroke_timing_interval, 1); 631 } 632 633 /* Don't hold off if obfuscation inactive */ 634 if (!active) 635 return 1; 636 637 if (had_keystroke) { 638 /* 639 * Arrange to send chaff packets for a random interval after 640 * the last keystroke was sent. 641 */ 642 ms_to_timespec(&tmp, SSH_KEYSTROKE_CHAFF_MIN_MS + 643 arc4random_uniform(SSH_KEYSTROKE_CHAFF_RNG_MS)); 644 timespecadd(&now, &tmp, &chaff_until); 645 } 646 647 ptimeout_deadline_monotime_tsp(timeout, &next_interval); 648 649 if (just_started) 650 return 1; 651 652 /* Don't arm output fd for poll until the timing interval has elapsed */ 653 if (timespeccmp(&now, &next_interval, <)) 654 return 0; 655 656 /* Calculate number of intervals missed since the last check */ 657 n = (now.tv_sec - next_interval.tv_sec) * 1000LL * 1000 * 1000; 658 n += now.tv_nsec - next_interval.tv_nsec; 659 n /= options.obscure_keystroke_timing_interval * 1000LL * 1000; 660 n = (n < 0) ? 1 : n + 1; 661 662 /* Advance to the next interval */ 663 set_next_interval(&now, &next_interval, 664 options.obscure_keystroke_timing_interval * n, 0); 665 return 1; 666 } 667 668 /* 669 * Waits until the client can do something (some data becomes available on 670 * one of the file descriptors). 671 */ 672 static void 673 client_wait_until_can_do_something(struct ssh *ssh, struct pollfd **pfdp, 674 u_int *npfd_allocp, u_int *npfd_activep, int channel_did_enqueue, 675 sigset_t *sigsetp, int *conn_in_readyp, int *conn_out_readyp) 676 { 677 struct timespec timeout; 678 int ret, oready; 679 u_int p; 680 681 *conn_in_readyp = *conn_out_readyp = 0; 682 683 /* Prepare channel poll. First two pollfd entries are reserved */ 684 ptimeout_init(&timeout); 685 channel_prepare_poll(ssh, pfdp, npfd_allocp, npfd_activep, 2, &timeout); 686 if (*npfd_activep < 2) 687 fatal_f("bad npfd %u", *npfd_activep); /* shouldn't happen */ 688 689 /* channel_prepare_poll could have closed the last channel */ 690 if (session_closed && !channel_still_open(ssh) && 691 !ssh_packet_have_data_to_write(ssh)) { 692 /* clear events since we did not call poll() */ 693 for (p = 0; p < *npfd_activep; p++) 694 (*pfdp)[p].revents = 0; 695 return; 696 } 697 698 oready = obfuscate_keystroke_timing(ssh, &timeout, channel_did_enqueue); 699 700 /* Monitor server connection on reserved pollfd entries */ 701 (*pfdp)[0].fd = connection_in; 702 (*pfdp)[0].events = POLLIN; 703 (*pfdp)[1].fd = connection_out; 704 (*pfdp)[1].events = (oready && ssh_packet_have_data_to_write(ssh)) ? 705 POLLOUT : 0; 706 707 /* 708 * Wait for something to happen. This will suspend the process until 709 * some polled descriptor can be read, written, or has some other 710 * event pending, or a timeout expires. 711 */ 712 set_control_persist_exit_time(ssh); 713 if (control_persist_exit_time > 0) 714 ptimeout_deadline_monotime(&timeout, control_persist_exit_time); 715 if (options.server_alive_interval > 0) 716 ptimeout_deadline_monotime(&timeout, server_alive_time); 717 if (options.rekey_interval > 0 && !ssh_packet_is_rekeying(ssh)) { 718 ptimeout_deadline_sec(&timeout, 719 ssh_packet_get_rekey_timeout(ssh)); 720 } 721 722 ret = ppoll(*pfdp, *npfd_activep, ptimeout_get_tsp(&timeout), sigsetp); 723 724 if (ret == -1) { 725 /* 726 * We have to clear the events because we return. 727 * We have to return, because the mainloop checks for the flags 728 * set by the signal handlers. 729 */ 730 for (p = 0; p < *npfd_activep; p++) 731 (*pfdp)[p].revents = 0; 732 if (errno == EINTR) 733 return; 734 /* Note: we might still have data in the buffers. */ 735 quit_message("poll: %s", strerror(errno)); 736 return; 737 } 738 739 *conn_in_readyp = (*pfdp)[0].revents != 0; 740 *conn_out_readyp = (*pfdp)[1].revents != 0; 741 742 if (options.server_alive_interval > 0 && !*conn_in_readyp && 743 monotime() >= server_alive_time) { 744 /* 745 * ServerAlive check is needed. We can't rely on the poll 746 * timing out since traffic on the client side such as port 747 * forwards can keep waking it up. 748 */ 749 server_alive_check(ssh); 750 } 751 } 752 753 static void 754 client_suspend_self(struct sshbuf *bin, struct sshbuf *bout, struct sshbuf *berr) 755 { 756 /* Flush stdout and stderr buffers. */ 757 if (sshbuf_len(bout) > 0) 758 atomicio(vwrite, fileno(stdout), sshbuf_mutable_ptr(bout), 759 sshbuf_len(bout)); 760 if (sshbuf_len(berr) > 0) 761 atomicio(vwrite, fileno(stderr), sshbuf_mutable_ptr(berr), 762 sshbuf_len(berr)); 763 764 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 765 766 sshbuf_reset(bin); 767 sshbuf_reset(bout); 768 sshbuf_reset(berr); 769 770 /* Send the suspend signal to the program itself. */ 771 kill(getpid(), SIGTSTP); 772 773 /* Reset window sizes in case they have changed */ 774 received_window_change_signal = 1; 775 776 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 777 } 778 779 static void 780 client_process_net_input(struct ssh *ssh) 781 { 782 int r; 783 784 /* 785 * Read input from the server, and add any such data to the buffer of 786 * the packet subsystem. 787 */ 788 schedule_server_alive_check(); 789 if ((r = ssh_packet_process_read(ssh, connection_in)) == 0) 790 return; /* success */ 791 if (r == SSH_ERR_SYSTEM_ERROR) { 792 if (errno == EAGAIN || errno == EINTR) 793 return; 794 if (errno == EPIPE) { 795 quit_message("Connection to %s closed by remote host.", 796 host); 797 return; 798 } 799 } 800 quit_message("Read from remote host %s: %s", host, ssh_err(r)); 801 } 802 803 static void 804 client_status_confirm(struct ssh *ssh, int type, Channel *c, void *ctx) 805 { 806 struct channel_reply_ctx *cr = (struct channel_reply_ctx *)ctx; 807 char errmsg[256]; 808 int r, tochan; 809 810 /* 811 * If a TTY was explicitly requested, then a failure to allocate 812 * one is fatal. 813 */ 814 if (cr->action == CONFIRM_TTY && 815 (options.request_tty == REQUEST_TTY_FORCE || 816 options.request_tty == REQUEST_TTY_YES)) 817 cr->action = CONFIRM_CLOSE; 818 819 /* XXX suppress on mux _client_ quietmode */ 820 tochan = options.log_level >= SYSLOG_LEVEL_ERROR && 821 c->ctl_chan != -1 && c->extended_usage == CHAN_EXTENDED_WRITE; 822 823 if (type == SSH2_MSG_CHANNEL_SUCCESS) { 824 debug2("%s request accepted on channel %d", 825 cr->request_type, c->self); 826 } else if (type == SSH2_MSG_CHANNEL_FAILURE) { 827 if (tochan) { 828 snprintf(errmsg, sizeof(errmsg), 829 "%s request failed\r\n", cr->request_type); 830 } else { 831 snprintf(errmsg, sizeof(errmsg), 832 "%s request failed on channel %d", 833 cr->request_type, c->self); 834 } 835 /* If error occurred on primary session channel, then exit */ 836 if (cr->action == CONFIRM_CLOSE && c->self == session_ident) 837 fatal("%s", errmsg); 838 /* 839 * If error occurred on mux client, append to 840 * their stderr. 841 */ 842 if (tochan) { 843 debug3_f("channel %d: mux request: %s", c->self, 844 cr->request_type); 845 if ((r = sshbuf_put(c->extended, errmsg, 846 strlen(errmsg))) != 0) 847 fatal_fr(r, "sshbuf_put"); 848 } else 849 error("%s", errmsg); 850 if (cr->action == CONFIRM_TTY) { 851 /* 852 * If a TTY allocation error occurred, then arrange 853 * for the correct TTY to leave raw mode. 854 */ 855 if (c->self == session_ident) 856 leave_raw_mode(0); 857 else 858 mux_tty_alloc_failed(ssh, c); 859 } else if (cr->action == CONFIRM_CLOSE) { 860 chan_read_failed(ssh, c); 861 chan_write_failed(ssh, c); 862 } 863 } 864 free(cr); 865 } 866 867 static void 868 client_abandon_status_confirm(struct ssh *ssh, Channel *c, void *ctx) 869 { 870 free(ctx); 871 } 872 873 void 874 client_expect_confirm(struct ssh *ssh, int id, const char *request, 875 enum confirm_action action) 876 { 877 struct channel_reply_ctx *cr = xcalloc(1, sizeof(*cr)); 878 879 cr->request_type = request; 880 cr->action = action; 881 882 channel_register_status_confirm(ssh, id, client_status_confirm, 883 client_abandon_status_confirm, cr); 884 } 885 886 void 887 client_register_global_confirm(global_confirm_cb *cb, void *ctx) 888 { 889 struct global_confirm *gc, *last_gc; 890 891 /* Coalesce identical callbacks */ 892 last_gc = TAILQ_LAST(&global_confirms, global_confirms); 893 if (last_gc && last_gc->cb == cb && last_gc->ctx == ctx) { 894 if (++last_gc->ref_count >= INT_MAX) 895 fatal_f("last_gc->ref_count = %d", 896 last_gc->ref_count); 897 return; 898 } 899 900 gc = xcalloc(1, sizeof(*gc)); 901 gc->cb = cb; 902 gc->ctx = ctx; 903 gc->ref_count = 1; 904 TAILQ_INSERT_TAIL(&global_confirms, gc, entry); 905 } 906 907 /* 908 * Returns non-zero if the client is able to handle a hostkeys-00@openssh.com 909 * hostkey update request. 910 */ 911 static int 912 can_update_hostkeys(void) 913 { 914 if (hostkeys_update_complete) 915 return 0; 916 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK && 917 options.batch_mode) 918 return 0; /* won't ask in batchmode, so don't even try */ 919 if (!options.update_hostkeys || options.num_user_hostfiles <= 0) 920 return 0; 921 return 1; 922 } 923 924 static void 925 client_repledge(void) 926 { 927 debug3_f("enter"); 928 929 /* Might be able to tighten pledge now that session is established */ 930 if (options.control_master || options.control_path != NULL || 931 options.forward_x11 || options.fork_after_authentication || 932 can_update_hostkeys() || 933 (session_ident != -1 && !session_setup_complete)) { 934 /* Can't tighten */ 935 return; 936 } 937 /* 938 * LocalCommand and UpdateHostkeys have finished, so can get rid of 939 * filesystem. 940 * 941 * XXX protocol allows a server can to change hostkeys during the 942 * connection at rekey time that could trigger a hostkeys update 943 * but AFAIK no implementations support this. Could improve by 944 * forcing known_hosts to be read-only or via unveil(2). 945 */ 946 if (options.num_local_forwards != 0 || 947 options.num_remote_forwards != 0 || 948 options.num_permitted_remote_opens != 0 || 949 options.enable_escape_commandline != 0) { 950 /* rfwd needs inet */ 951 debug("pledge: network"); 952 if (pledge("stdio unix inet dns proc tty", NULL) == -1) 953 fatal_f("pledge(): %s", strerror(errno)); 954 } else if (options.forward_agent != 0) { 955 /* agent forwarding needs to open $SSH_AUTH_SOCK at will */ 956 debug("pledge: agent"); 957 if (pledge("stdio unix proc tty", NULL) == -1) 958 fatal_f("pledge(): %s", strerror(errno)); 959 } else { 960 debug("pledge: fork"); 961 if (pledge("stdio proc tty", NULL) == -1) 962 fatal_f("pledge(): %s", strerror(errno)); 963 } 964 /* XXX further things to do: 965 * 966 * - might be able to get rid of proc if we kill ~^Z 967 * - ssh -N (no session) 968 * - stdio forwarding 969 * - sessions without tty 970 */ 971 } 972 973 static void 974 process_cmdline(struct ssh *ssh) 975 { 976 void (*handler)(int); 977 char *s, *cmd; 978 int ok, delete = 0, local = 0, remote = 0, dynamic = 0; 979 struct Forward fwd; 980 981 memset(&fwd, 0, sizeof(fwd)); 982 983 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 984 handler = ssh_signal(SIGINT, SIG_IGN); 985 cmd = s = read_passphrase("\r\nssh> ", RP_ECHO); 986 if (s == NULL) 987 goto out; 988 while (isspace((u_char)*s)) 989 s++; 990 if (*s == '-') 991 s++; /* Skip cmdline '-', if any */ 992 if (*s == '\0') 993 goto out; 994 995 if (*s == 'h' || *s == 'H' || *s == '?') { 996 logit("Commands:"); 997 logit(" -L[bind_address:]port:host:hostport " 998 "Request local forward"); 999 logit(" -R[bind_address:]port:host:hostport " 1000 "Request remote forward"); 1001 logit(" -D[bind_address:]port " 1002 "Request dynamic forward"); 1003 logit(" -KL[bind_address:]port " 1004 "Cancel local forward"); 1005 logit(" -KR[bind_address:]port " 1006 "Cancel remote forward"); 1007 logit(" -KD[bind_address:]port " 1008 "Cancel dynamic forward"); 1009 if (!options.permit_local_command) 1010 goto out; 1011 logit(" !args " 1012 "Execute local command"); 1013 goto out; 1014 } 1015 1016 if (*s == '!' && options.permit_local_command) { 1017 s++; 1018 ssh_local_cmd(s); 1019 goto out; 1020 } 1021 1022 if (*s == 'K') { 1023 delete = 1; 1024 s++; 1025 } 1026 if (*s == 'L') 1027 local = 1; 1028 else if (*s == 'R') 1029 remote = 1; 1030 else if (*s == 'D') 1031 dynamic = 1; 1032 else { 1033 logit("Invalid command."); 1034 goto out; 1035 } 1036 1037 while (isspace((u_char)*++s)) 1038 ; 1039 1040 /* XXX update list of forwards in options */ 1041 if (delete) { 1042 /* We pass 1 for dynamicfwd to restrict to 1 or 2 fields. */ 1043 if (!parse_forward(&fwd, s, 1, 0)) { 1044 logit("Bad forwarding close specification."); 1045 goto out; 1046 } 1047 if (remote) 1048 ok = channel_request_rforward_cancel(ssh, &fwd) == 0; 1049 else if (dynamic) 1050 ok = channel_cancel_lport_listener(ssh, &fwd, 1051 0, &options.fwd_opts) > 0; 1052 else 1053 ok = channel_cancel_lport_listener(ssh, &fwd, 1054 CHANNEL_CANCEL_PORT_STATIC, 1055 &options.fwd_opts) > 0; 1056 if (!ok) { 1057 logit("Unknown port forwarding."); 1058 goto out; 1059 } 1060 logit("Canceled forwarding."); 1061 } else { 1062 /* -R specs can be both dynamic or not, so check both. */ 1063 if (remote) { 1064 if (!parse_forward(&fwd, s, 0, remote) && 1065 !parse_forward(&fwd, s, 1, remote)) { 1066 logit("Bad remote forwarding specification."); 1067 goto out; 1068 } 1069 } else if (!parse_forward(&fwd, s, dynamic, remote)) { 1070 logit("Bad local forwarding specification."); 1071 goto out; 1072 } 1073 if (local || dynamic) { 1074 if (!channel_setup_local_fwd_listener(ssh, &fwd, 1075 &options.fwd_opts)) { 1076 logit("Port forwarding failed."); 1077 goto out; 1078 } 1079 } else { 1080 if (channel_request_remote_forwarding(ssh, &fwd) < 0) { 1081 logit("Port forwarding failed."); 1082 goto out; 1083 } 1084 } 1085 logit("Forwarding port."); 1086 } 1087 1088 out: 1089 ssh_signal(SIGINT, handler); 1090 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1091 free(cmd); 1092 free(fwd.listen_host); 1093 free(fwd.listen_path); 1094 free(fwd.connect_host); 1095 free(fwd.connect_path); 1096 } 1097 1098 /* reasons to suppress output of an escape command in help output */ 1099 #define SUPPRESS_NEVER 0 /* never suppress, always show */ 1100 #define SUPPRESS_MUXCLIENT 1 /* don't show in mux client sessions */ 1101 #define SUPPRESS_MUXMASTER 2 /* don't show in mux master sessions */ 1102 #define SUPPRESS_SYSLOG 4 /* don't show when logging to syslog */ 1103 #define SUPPRESS_NOCMDLINE 8 /* don't show when cmdline disabled*/ 1104 struct escape_help_text { 1105 const char *cmd; 1106 const char *text; 1107 unsigned int flags; 1108 }; 1109 static struct escape_help_text esc_txt[] = { 1110 {".", "terminate session", SUPPRESS_MUXMASTER}, 1111 {".", "terminate connection (and any multiplexed sessions)", 1112 SUPPRESS_MUXCLIENT}, 1113 {"B", "send a BREAK to the remote system", SUPPRESS_NEVER}, 1114 {"C", "open a command line", SUPPRESS_MUXCLIENT|SUPPRESS_NOCMDLINE}, 1115 {"R", "request rekey", SUPPRESS_NEVER}, 1116 {"V/v", "decrease/increase verbosity (LogLevel)", SUPPRESS_MUXCLIENT}, 1117 {"^Z", "suspend ssh", SUPPRESS_MUXCLIENT}, 1118 {"#", "list forwarded connections", SUPPRESS_NEVER}, 1119 {"&", "background ssh (when waiting for connections to terminate)", 1120 SUPPRESS_MUXCLIENT}, 1121 {"?", "this message", SUPPRESS_NEVER}, 1122 }; 1123 1124 static void 1125 print_escape_help(struct sshbuf *b, int escape_char, int mux_client, 1126 int using_stderr) 1127 { 1128 unsigned int i, suppress_flags; 1129 int r; 1130 1131 if ((r = sshbuf_putf(b, 1132 "%c?\r\nSupported escape sequences:\r\n", escape_char)) != 0) 1133 fatal_fr(r, "sshbuf_putf"); 1134 1135 suppress_flags = 1136 (mux_client ? SUPPRESS_MUXCLIENT : 0) | 1137 (mux_client ? 0 : SUPPRESS_MUXMASTER) | 1138 (using_stderr ? 0 : SUPPRESS_SYSLOG) | 1139 (options.enable_escape_commandline == 0 ? SUPPRESS_NOCMDLINE : 0); 1140 1141 for (i = 0; i < sizeof(esc_txt)/sizeof(esc_txt[0]); i++) { 1142 if (esc_txt[i].flags & suppress_flags) 1143 continue; 1144 if ((r = sshbuf_putf(b, " %c%-3s - %s\r\n", 1145 escape_char, esc_txt[i].cmd, esc_txt[i].text)) != 0) 1146 fatal_fr(r, "sshbuf_putf"); 1147 } 1148 1149 if ((r = sshbuf_putf(b, 1150 " %c%c - send the escape character by typing it twice\r\n" 1151 "(Note that escapes are only recognized immediately after " 1152 "newline.)\r\n", escape_char, escape_char)) != 0) 1153 fatal_fr(r, "sshbuf_putf"); 1154 } 1155 1156 /* 1157 * Process the characters one by one. 1158 */ 1159 static int 1160 process_escapes(struct ssh *ssh, Channel *c, 1161 struct sshbuf *bin, struct sshbuf *bout, struct sshbuf *berr, 1162 char *buf, int len) 1163 { 1164 pid_t pid; 1165 int r, bytes = 0; 1166 u_int i; 1167 u_char ch; 1168 char *s; 1169 struct escape_filter_ctx *efc; 1170 1171 if (c == NULL || c->filter_ctx == NULL || len <= 0) 1172 return 0; 1173 1174 efc = (struct escape_filter_ctx *)c->filter_ctx; 1175 1176 for (i = 0; i < (u_int)len; i++) { 1177 /* Get one character at a time. */ 1178 ch = buf[i]; 1179 1180 if (efc->escape_pending) { 1181 /* We have previously seen an escape character. */ 1182 /* Clear the flag now. */ 1183 efc->escape_pending = 0; 1184 1185 /* Process the escaped character. */ 1186 switch (ch) { 1187 case '.': 1188 /* Terminate the connection. */ 1189 if ((r = sshbuf_putf(berr, "%c.\r\n", 1190 efc->escape_char)) != 0) 1191 fatal_fr(r, "sshbuf_putf"); 1192 if (c && c->ctl_chan != -1) { 1193 channel_force_close(ssh, c, 1); 1194 return 0; 1195 } else 1196 quit_pending = 1; 1197 return -1; 1198 1199 case 'Z' - 64: 1200 /* XXX support this for mux clients */ 1201 if (c && c->ctl_chan != -1) { 1202 char b[16]; 1203 noescape: 1204 if (ch == 'Z' - 64) 1205 snprintf(b, sizeof b, "^Z"); 1206 else 1207 snprintf(b, sizeof b, "%c", ch); 1208 if ((r = sshbuf_putf(berr, 1209 "%c%s escape not available to " 1210 "multiplexed sessions\r\n", 1211 efc->escape_char, b)) != 0) 1212 fatal_fr(r, "sshbuf_putf"); 1213 continue; 1214 } 1215 /* Suspend the program. Inform the user */ 1216 if ((r = sshbuf_putf(berr, 1217 "%c^Z [suspend ssh]\r\n", 1218 efc->escape_char)) != 0) 1219 fatal_fr(r, "sshbuf_putf"); 1220 1221 /* Restore terminal modes and suspend. */ 1222 client_suspend_self(bin, bout, berr); 1223 1224 /* We have been continued. */ 1225 continue; 1226 1227 case 'B': 1228 if ((r = sshbuf_putf(berr, 1229 "%cB\r\n", efc->escape_char)) != 0) 1230 fatal_fr(r, "sshbuf_putf"); 1231 channel_request_start(ssh, c->self, "break", 0); 1232 if ((r = sshpkt_put_u32(ssh, 1000)) != 0 || 1233 (r = sshpkt_send(ssh)) != 0) 1234 fatal_fr(r, "send packet"); 1235 continue; 1236 1237 case 'R': 1238 if (ssh->compat & SSH_BUG_NOREKEY) 1239 logit("Server does not " 1240 "support re-keying"); 1241 else 1242 need_rekeying = 1; 1243 continue; 1244 1245 case 'V': 1246 /* FALLTHROUGH */ 1247 case 'v': 1248 if (c && c->ctl_chan != -1) 1249 goto noescape; 1250 if (!log_is_on_stderr()) { 1251 if ((r = sshbuf_putf(berr, 1252 "%c%c [Logging to syslog]\r\n", 1253 efc->escape_char, ch)) != 0) 1254 fatal_fr(r, "sshbuf_putf"); 1255 continue; 1256 } 1257 if (ch == 'V' && options.log_level > 1258 SYSLOG_LEVEL_QUIET) 1259 log_change_level(--options.log_level); 1260 if (ch == 'v' && options.log_level < 1261 SYSLOG_LEVEL_DEBUG3) 1262 log_change_level(++options.log_level); 1263 if ((r = sshbuf_putf(berr, 1264 "%c%c [LogLevel %s]\r\n", 1265 efc->escape_char, ch, 1266 log_level_name(options.log_level))) != 0) 1267 fatal_fr(r, "sshbuf_putf"); 1268 continue; 1269 1270 case '&': 1271 if (c->ctl_chan != -1) 1272 goto noescape; 1273 /* 1274 * Detach the program (continue to serve 1275 * connections, but put in background and no 1276 * more new connections). 1277 */ 1278 /* Restore tty modes. */ 1279 leave_raw_mode( 1280 options.request_tty == REQUEST_TTY_FORCE); 1281 1282 /* Stop listening for new connections. */ 1283 channel_stop_listening(ssh); 1284 1285 if ((r = sshbuf_putf(berr, "%c& " 1286 "[backgrounded]\n", efc->escape_char)) != 0) 1287 fatal_fr(r, "sshbuf_putf"); 1288 1289 /* Fork into background. */ 1290 pid = fork(); 1291 if (pid == -1) { 1292 error("fork: %.100s", strerror(errno)); 1293 continue; 1294 } 1295 if (pid != 0) { /* This is the parent. */ 1296 /* The parent just exits. */ 1297 exit(0); 1298 } 1299 /* The child continues serving connections. */ 1300 /* fake EOF on stdin */ 1301 if ((r = sshbuf_put_u8(bin, 4)) != 0) 1302 fatal_fr(r, "sshbuf_put_u8"); 1303 return -1; 1304 case '?': 1305 print_escape_help(berr, efc->escape_char, 1306 (c && c->ctl_chan != -1), 1307 log_is_on_stderr()); 1308 continue; 1309 1310 case '#': 1311 if ((r = sshbuf_putf(berr, "%c#\r\n", 1312 efc->escape_char)) != 0) 1313 fatal_fr(r, "sshbuf_putf"); 1314 s = channel_open_message(ssh); 1315 if ((r = sshbuf_put(berr, s, strlen(s))) != 0) 1316 fatal_fr(r, "sshbuf_put"); 1317 free(s); 1318 continue; 1319 1320 case 'C': 1321 if (c && c->ctl_chan != -1) 1322 goto noescape; 1323 if (options.enable_escape_commandline == 0) { 1324 if ((r = sshbuf_putf(berr, 1325 "commandline disabled\r\n")) != 0) 1326 fatal_fr(r, "sshbuf_putf"); 1327 continue; 1328 } 1329 process_cmdline(ssh); 1330 continue; 1331 1332 default: 1333 if (ch != efc->escape_char) { 1334 if ((r = sshbuf_put_u8(bin, 1335 efc->escape_char)) != 0) 1336 fatal_fr(r, "sshbuf_put_u8"); 1337 bytes++; 1338 } 1339 /* Escaped characters fall through here */ 1340 break; 1341 } 1342 } else { 1343 /* 1344 * The previous character was not an escape char. 1345 * Check if this is an escape. 1346 */ 1347 if (last_was_cr && ch == efc->escape_char) { 1348 /* 1349 * It is. Set the flag and continue to 1350 * next character. 1351 */ 1352 efc->escape_pending = 1; 1353 continue; 1354 } 1355 } 1356 1357 /* 1358 * Normal character. Record whether it was a newline, 1359 * and append it to the buffer. 1360 */ 1361 last_was_cr = (ch == '\r' || ch == '\n'); 1362 if ((r = sshbuf_put_u8(bin, ch)) != 0) 1363 fatal_fr(r, "sshbuf_put_u8"); 1364 bytes++; 1365 } 1366 return bytes; 1367 } 1368 1369 /* 1370 * Get packets from the connection input buffer, and process them as long as 1371 * there are packets available. 1372 * 1373 * Any unknown packets received during the actual 1374 * session cause the session to terminate. This is 1375 * intended to make debugging easier since no 1376 * confirmations are sent. Any compatible protocol 1377 * extensions must be negotiated during the 1378 * preparatory phase. 1379 */ 1380 1381 static void 1382 client_process_buffered_input_packets(struct ssh *ssh) 1383 { 1384 ssh_dispatch_run_fatal(ssh, DISPATCH_NONBLOCK, &quit_pending); 1385 } 1386 1387 /* scan buf[] for '~' before sending data to the peer */ 1388 1389 /* Helper: allocate a new escape_filter_ctx and fill in its escape char */ 1390 void * 1391 client_new_escape_filter_ctx(int escape_char) 1392 { 1393 struct escape_filter_ctx *ret; 1394 1395 ret = xcalloc(1, sizeof(*ret)); 1396 ret->escape_pending = 0; 1397 ret->escape_char = escape_char; 1398 return (void *)ret; 1399 } 1400 1401 /* Free the escape filter context on channel free */ 1402 void 1403 client_filter_cleanup(struct ssh *ssh, int cid, void *ctx) 1404 { 1405 free(ctx); 1406 } 1407 1408 int 1409 client_simple_escape_filter(struct ssh *ssh, Channel *c, char *buf, int len) 1410 { 1411 if (c->extended_usage != CHAN_EXTENDED_WRITE) 1412 return 0; 1413 1414 return process_escapes(ssh, c, c->input, c->output, c->extended, 1415 buf, len); 1416 } 1417 1418 static void 1419 client_channel_closed(struct ssh *ssh, int id, int force, void *arg) 1420 { 1421 channel_cancel_cleanup(ssh, id); 1422 session_closed = 1; 1423 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1424 } 1425 1426 /* 1427 * Implements the interactive session with the server. This is called after 1428 * the user has been authenticated, and a command has been started on the 1429 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character 1430 * used as an escape character for terminating or suspending the session. 1431 */ 1432 int 1433 client_loop(struct ssh *ssh, int have_pty, int escape_char_arg, 1434 int ssh2_chan_id) 1435 { 1436 struct pollfd *pfd = NULL; 1437 u_int npfd_alloc = 0, npfd_active = 0; 1438 double start_time, total_time; 1439 int channel_did_enqueue = 0, r; 1440 u_int64_t ibytes, obytes; 1441 int conn_in_ready, conn_out_ready; 1442 sigset_t bsigset, osigset; 1443 1444 debug("Entering interactive session."); 1445 session_ident = ssh2_chan_id; 1446 1447 if (options.control_master && 1448 !option_clear_or_none(options.control_path)) { 1449 debug("pledge: id"); 1450 if (pledge("stdio rpath wpath cpath unix inet dns recvfd sendfd proc exec id tty", 1451 NULL) == -1) 1452 fatal_f("pledge(): %s", strerror(errno)); 1453 1454 } else if (options.forward_x11 || options.permit_local_command) { 1455 debug("pledge: exec"); 1456 if (pledge("stdio rpath wpath cpath unix inet dns proc exec tty", 1457 NULL) == -1) 1458 fatal_f("pledge(): %s", strerror(errno)); 1459 1460 } else if (options.update_hostkeys) { 1461 debug("pledge: filesystem"); 1462 if (pledge("stdio rpath wpath cpath unix inet dns proc tty", 1463 NULL) == -1) 1464 fatal_f("pledge(): %s", strerror(errno)); 1465 1466 } else if (!option_clear_or_none(options.proxy_command) || 1467 options.fork_after_authentication) { 1468 debug("pledge: proc"); 1469 if (pledge("stdio cpath unix inet dns proc tty", NULL) == -1) 1470 fatal_f("pledge(): %s", strerror(errno)); 1471 1472 } else { 1473 debug("pledge: network"); 1474 if (pledge("stdio unix inet dns proc tty", NULL) == -1) 1475 fatal_f("pledge(): %s", strerror(errno)); 1476 } 1477 1478 /* might be able to tighten now */ 1479 client_repledge(); 1480 1481 start_time = monotime_double(); 1482 1483 /* Initialize variables. */ 1484 last_was_cr = 1; 1485 exit_status = -1; 1486 connection_in = ssh_packet_get_connection_in(ssh); 1487 connection_out = ssh_packet_get_connection_out(ssh); 1488 1489 quit_pending = 0; 1490 1491 client_init_dispatch(ssh); 1492 1493 /* 1494 * Set signal handlers, (e.g. to restore non-blocking mode) 1495 * but don't overwrite SIG_IGN, matches behaviour from rsh(1) 1496 */ 1497 if (ssh_signal(SIGHUP, SIG_IGN) != SIG_IGN) 1498 ssh_signal(SIGHUP, signal_handler); 1499 if (ssh_signal(SIGINT, SIG_IGN) != SIG_IGN) 1500 ssh_signal(SIGINT, signal_handler); 1501 if (ssh_signal(SIGQUIT, SIG_IGN) != SIG_IGN) 1502 ssh_signal(SIGQUIT, signal_handler); 1503 if (ssh_signal(SIGTERM, SIG_IGN) != SIG_IGN) 1504 ssh_signal(SIGTERM, signal_handler); 1505 ssh_signal(SIGWINCH, window_change_handler); 1506 1507 if (have_pty) 1508 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1509 1510 if (session_ident != -1) { 1511 if (escape_char_arg != SSH_ESCAPECHAR_NONE) { 1512 channel_register_filter(ssh, session_ident, 1513 client_simple_escape_filter, NULL, 1514 client_filter_cleanup, 1515 client_new_escape_filter_ctx( 1516 escape_char_arg)); 1517 } 1518 channel_register_cleanup(ssh, session_ident, 1519 client_channel_closed, 0); 1520 } 1521 1522 schedule_server_alive_check(); 1523 1524 if (sigemptyset(&bsigset) == -1 || 1525 sigaddset(&bsigset, SIGHUP) == -1 || 1526 sigaddset(&bsigset, SIGINT) == -1 || 1527 sigaddset(&bsigset, SIGQUIT) == -1 || 1528 sigaddset(&bsigset, SIGTERM) == -1) 1529 error_f("bsigset setup: %s", strerror(errno)); 1530 1531 /* Main loop of the client for the interactive session mode. */ 1532 while (!quit_pending) { 1533 channel_did_enqueue = 0; 1534 1535 /* Process buffered packets sent by the server. */ 1536 client_process_buffered_input_packets(ssh); 1537 1538 if (session_closed && !channel_still_open(ssh)) 1539 break; 1540 1541 if (ssh_packet_is_rekeying(ssh)) { 1542 debug("rekeying in progress"); 1543 } else if (need_rekeying) { 1544 /* manual rekey request */ 1545 debug("need rekeying"); 1546 if ((r = kex_start_rekex(ssh)) != 0) 1547 fatal_fr(r, "kex_start_rekex"); 1548 need_rekeying = 0; 1549 } else { 1550 /* 1551 * Make packets from buffered channel data, and 1552 * enqueue them for sending to the server. 1553 */ 1554 if (ssh_packet_not_very_much_data_to_write(ssh)) 1555 channel_did_enqueue = channel_output_poll(ssh); 1556 1557 /* 1558 * Check if the window size has changed, and buffer a 1559 * message about it to the server if so. 1560 */ 1561 client_check_window_change(ssh); 1562 } 1563 /* 1564 * Wait until we have something to do (something becomes 1565 * available on one of the descriptors). 1566 */ 1567 if (sigprocmask(SIG_BLOCK, &bsigset, &osigset) == -1) 1568 error_f("bsigset sigprocmask: %s", strerror(errno)); 1569 if (quit_pending) 1570 break; 1571 client_wait_until_can_do_something(ssh, &pfd, &npfd_alloc, 1572 &npfd_active, channel_did_enqueue, &osigset, 1573 &conn_in_ready, &conn_out_ready); 1574 if (sigprocmask(SIG_SETMASK, &osigset, NULL) == -1) 1575 error_f("osigset sigprocmask: %s", strerror(errno)); 1576 1577 if (quit_pending) 1578 break; 1579 1580 /* Do channel operations. */ 1581 channel_after_poll(ssh, pfd, npfd_active); 1582 1583 /* Buffer input from the connection. */ 1584 if (conn_in_ready) 1585 client_process_net_input(ssh); 1586 1587 if (quit_pending) 1588 break; 1589 1590 /* A timeout may have triggered rekeying */ 1591 if ((r = ssh_packet_check_rekey(ssh)) != 0) 1592 fatal_fr(r, "cannot start rekeying"); 1593 1594 /* 1595 * Send as much buffered packet data as possible to the 1596 * sender. 1597 */ 1598 if (conn_out_ready) { 1599 if ((r = ssh_packet_write_poll(ssh)) != 0) { 1600 sshpkt_fatal(ssh, r, 1601 "%s: ssh_packet_write_poll", __func__); 1602 } 1603 } 1604 1605 /* 1606 * If we are a backgrounded control master, and the 1607 * timeout has expired without any active client 1608 * connections, then quit. 1609 */ 1610 if (control_persist_exit_time > 0) { 1611 if (monotime() >= control_persist_exit_time) { 1612 debug("ControlPersist timeout expired"); 1613 break; 1614 } 1615 } 1616 } 1617 free(pfd); 1618 1619 /* Terminate the session. */ 1620 1621 /* 1622 * In interactive mode (with pseudo tty) display a message indicating 1623 * that the connection has been closed. 1624 */ 1625 if (have_pty && options.log_level >= SYSLOG_LEVEL_INFO) 1626 quit_message("Connection to %s closed.", host); 1627 1628 1629 /* Stop watching for window change. */ 1630 ssh_signal(SIGWINCH, SIG_DFL); 1631 1632 if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 || 1633 (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_BY_APPLICATION)) != 0 || 1634 (r = sshpkt_put_cstring(ssh, "disconnected by user")) != 0 || 1635 (r = sshpkt_put_cstring(ssh, "")) != 0 || /* language tag */ 1636 (r = sshpkt_send(ssh)) != 0 || 1637 (r = ssh_packet_write_wait(ssh)) != 0) 1638 fatal_fr(r, "send disconnect"); 1639 1640 channel_free_all(ssh); 1641 1642 if (have_pty) 1643 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1644 1645 /* 1646 * If there was no shell or command requested, there will be no remote 1647 * exit status to be returned. In that case, clear error code if the 1648 * connection was deliberately terminated at this end. 1649 */ 1650 if (options.session_type == SESSION_TYPE_NONE && 1651 received_signal == SIGTERM) { 1652 received_signal = 0; 1653 exit_status = 0; 1654 } 1655 1656 if (received_signal) { 1657 verbose("Killed by signal %d.", (int) received_signal); 1658 cleanup_exit(255); 1659 } 1660 1661 /* Report bytes transferred, and transfer rates. */ 1662 total_time = monotime_double() - start_time; 1663 ssh_packet_get_bytes(ssh, &ibytes, &obytes); 1664 verbose("Transferred: sent %llu, received %llu bytes, in %.1f seconds", 1665 (unsigned long long)obytes, (unsigned long long)ibytes, total_time); 1666 if (total_time > 0) 1667 verbose("Bytes per second: sent %.1f, received %.1f", 1668 obytes / total_time, ibytes / total_time); 1669 /* Return the exit status of the program. */ 1670 debug("Exit status %d", exit_status); 1671 return exit_status; 1672 } 1673 1674 /*********/ 1675 1676 static Channel * 1677 client_request_forwarded_tcpip(struct ssh *ssh, const char *request_type, 1678 int rchan, u_int rwindow, u_int rmaxpack) 1679 { 1680 Channel *c = NULL; 1681 struct sshbuf *b = NULL; 1682 char *listen_address, *originator_address; 1683 u_int listen_port, originator_port; 1684 int r; 1685 1686 /* Get rest of the packet */ 1687 if ((r = sshpkt_get_cstring(ssh, &listen_address, NULL)) != 0 || 1688 (r = sshpkt_get_u32(ssh, &listen_port)) != 0 || 1689 (r = sshpkt_get_cstring(ssh, &originator_address, NULL)) != 0 || 1690 (r = sshpkt_get_u32(ssh, &originator_port)) != 0 || 1691 (r = sshpkt_get_end(ssh)) != 0) 1692 fatal_fr(r, "parse packet"); 1693 1694 debug_f("listen %s port %d, originator %s port %d", 1695 listen_address, listen_port, originator_address, originator_port); 1696 1697 if (listen_port > 0xffff) 1698 error_f("invalid listen port"); 1699 else if (originator_port > 0xffff) 1700 error_f("invalid originator port"); 1701 else { 1702 c = channel_connect_by_listen_address(ssh, 1703 listen_address, listen_port, "forwarded-tcpip", 1704 originator_address); 1705 } 1706 1707 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) { 1708 if ((b = sshbuf_new()) == NULL) { 1709 error_f("alloc reply"); 1710 goto out; 1711 } 1712 /* reconstruct and send to muxclient */ 1713 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 1714 (r = sshbuf_put_u8(b, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1715 (r = sshbuf_put_cstring(b, request_type)) != 0 || 1716 (r = sshbuf_put_u32(b, rchan)) != 0 || 1717 (r = sshbuf_put_u32(b, rwindow)) != 0 || 1718 (r = sshbuf_put_u32(b, rmaxpack)) != 0 || 1719 (r = sshbuf_put_cstring(b, listen_address)) != 0 || 1720 (r = sshbuf_put_u32(b, listen_port)) != 0 || 1721 (r = sshbuf_put_cstring(b, originator_address)) != 0 || 1722 (r = sshbuf_put_u32(b, originator_port)) != 0 || 1723 (r = sshbuf_put_stringb(c->output, b)) != 0) { 1724 error_fr(r, "compose for muxclient"); 1725 goto out; 1726 } 1727 } 1728 1729 out: 1730 sshbuf_free(b); 1731 free(originator_address); 1732 free(listen_address); 1733 return c; 1734 } 1735 1736 static Channel * 1737 client_request_forwarded_streamlocal(struct ssh *ssh, 1738 const char *request_type, int rchan) 1739 { 1740 Channel *c = NULL; 1741 char *listen_path; 1742 int r; 1743 1744 /* Get the remote path. */ 1745 if ((r = sshpkt_get_cstring(ssh, &listen_path, NULL)) != 0 || 1746 (r = sshpkt_get_string(ssh, NULL, NULL)) != 0 || /* reserved */ 1747 (r = sshpkt_get_end(ssh)) != 0) 1748 fatal_fr(r, "parse packet"); 1749 1750 debug_f("request: %s", listen_path); 1751 1752 c = channel_connect_by_listen_path(ssh, listen_path, 1753 "forwarded-streamlocal@openssh.com", "forwarded-streamlocal"); 1754 free(listen_path); 1755 return c; 1756 } 1757 1758 static Channel * 1759 client_request_x11(struct ssh *ssh, const char *request_type, int rchan) 1760 { 1761 Channel *c = NULL; 1762 char *originator; 1763 u_int originator_port; 1764 int r, sock; 1765 1766 if (!options.forward_x11) { 1767 error("Warning: ssh server tried X11 forwarding."); 1768 error("Warning: this is probably a break-in attempt by a " 1769 "malicious server."); 1770 return NULL; 1771 } 1772 if (x11_refuse_time != 0 && monotime() >= x11_refuse_time) { 1773 verbose("Rejected X11 connection after ForwardX11Timeout " 1774 "expired"); 1775 return NULL; 1776 } 1777 if ((r = sshpkt_get_cstring(ssh, &originator, NULL)) != 0 || 1778 (r = sshpkt_get_u32(ssh, &originator_port)) != 0 || 1779 (r = sshpkt_get_end(ssh)) != 0) 1780 fatal_fr(r, "parse packet"); 1781 /* XXX check permission */ 1782 /* XXX range check originator port? */ 1783 debug("client_request_x11: request from %s %u", originator, 1784 originator_port); 1785 free(originator); 1786 sock = x11_connect_display(ssh); 1787 if (sock < 0) 1788 return NULL; 1789 c = channel_new(ssh, "x11-connection", 1790 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1791 CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); 1792 c->force_drain = 1; 1793 return c; 1794 } 1795 1796 static Channel * 1797 client_request_agent(struct ssh *ssh, const char *request_type, int rchan) 1798 { 1799 Channel *c = NULL; 1800 int r, sock; 1801 1802 if (!options.forward_agent) { 1803 error("Warning: ssh server tried agent forwarding."); 1804 error("Warning: this is probably a break-in attempt by a " 1805 "malicious server."); 1806 return NULL; 1807 } 1808 if (forward_agent_sock_path == NULL) { 1809 r = ssh_get_authentication_socket(&sock); 1810 } else { 1811 r = ssh_get_authentication_socket_path(forward_agent_sock_path, &sock); 1812 } 1813 if (r != 0) { 1814 if (r != SSH_ERR_AGENT_NOT_PRESENT) 1815 debug_fr(r, "ssh_get_authentication_socket"); 1816 return NULL; 1817 } 1818 if ((r = ssh_agent_bind_hostkey(sock, ssh->kex->initial_hostkey, 1819 ssh->kex->session_id, ssh->kex->initial_sig, 1)) == 0) 1820 debug_f("bound agent to hostkey"); 1821 else 1822 debug2_fr(r, "ssh_agent_bind_hostkey"); 1823 1824 c = channel_new(ssh, "agent-connection", 1825 SSH_CHANNEL_OPEN, sock, sock, -1, 1826 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, 1827 "authentication agent connection", 1); 1828 c->force_drain = 1; 1829 return c; 1830 } 1831 1832 char * 1833 client_request_tun_fwd(struct ssh *ssh, int tun_mode, 1834 int local_tun, int remote_tun, channel_open_fn *cb, void *cbctx) 1835 { 1836 Channel *c; 1837 int r, fd; 1838 char *ifname = NULL; 1839 1840 if (tun_mode == SSH_TUNMODE_NO) 1841 return 0; 1842 1843 debug("Requesting tun unit %d in mode %d", local_tun, tun_mode); 1844 1845 /* Open local tunnel device */ 1846 if ((fd = tun_open(local_tun, tun_mode, &ifname)) == -1) { 1847 error("Tunnel device open failed."); 1848 return NULL; 1849 } 1850 debug("Tunnel forwarding using interface %s", ifname); 1851 1852 c = channel_new(ssh, "tun-connection", SSH_CHANNEL_OPENING, fd, fd, -1, 1853 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1); 1854 c->datagram = 1; 1855 1856 if (cb != NULL) 1857 channel_register_open_confirm(ssh, c->self, cb, cbctx); 1858 1859 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1860 (r = sshpkt_put_cstring(ssh, "tun@openssh.com")) != 0 || 1861 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1862 (r = sshpkt_put_u32(ssh, c->local_window_max)) != 0 || 1863 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 1864 (r = sshpkt_put_u32(ssh, tun_mode)) != 0 || 1865 (r = sshpkt_put_u32(ssh, remote_tun)) != 0 || 1866 (r = sshpkt_send(ssh)) != 0) 1867 sshpkt_fatal(ssh, r, "%s: send reply", __func__); 1868 1869 return ifname; 1870 } 1871 1872 /* XXXX move to generic input handler */ 1873 static int 1874 client_input_channel_open(int type, u_int32_t seq, struct ssh *ssh) 1875 { 1876 Channel *c = NULL; 1877 char *ctype = NULL; 1878 int r; 1879 u_int rchan; 1880 size_t len; 1881 u_int rmaxpack, rwindow; 1882 1883 if ((r = sshpkt_get_cstring(ssh, &ctype, &len)) != 0 || 1884 (r = sshpkt_get_u32(ssh, &rchan)) != 0 || 1885 (r = sshpkt_get_u32(ssh, &rwindow)) != 0 || 1886 (r = sshpkt_get_u32(ssh, &rmaxpack)) != 0) 1887 goto out; 1888 1889 debug("client_input_channel_open: ctype %s rchan %d win %d max %d", 1890 ctype, rchan, rwindow, rmaxpack); 1891 1892 if (strcmp(ctype, "forwarded-tcpip") == 0) { 1893 c = client_request_forwarded_tcpip(ssh, ctype, rchan, rwindow, 1894 rmaxpack); 1895 } else if (strcmp(ctype, "forwarded-streamlocal@openssh.com") == 0) { 1896 c = client_request_forwarded_streamlocal(ssh, ctype, rchan); 1897 } else if (strcmp(ctype, "x11") == 0) { 1898 c = client_request_x11(ssh, ctype, rchan); 1899 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) { 1900 c = client_request_agent(ssh, ctype, rchan); 1901 } 1902 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) { 1903 debug3("proxied to downstream: %s", ctype); 1904 } else if (c != NULL) { 1905 debug("confirm %s", ctype); 1906 c->remote_id = rchan; 1907 c->have_remote_id = 1; 1908 c->remote_window = rwindow; 1909 c->remote_maxpacket = rmaxpack; 1910 if (c->type != SSH_CHANNEL_CONNECTING) { 1911 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 1912 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1913 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1914 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1915 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 1916 (r = sshpkt_send(ssh)) != 0) 1917 sshpkt_fatal(ssh, r, "%s: send reply", __func__); 1918 } 1919 } else { 1920 debug("failure %s", ctype); 1921 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || 1922 (r = sshpkt_put_u32(ssh, rchan)) != 0 || 1923 (r = sshpkt_put_u32(ssh, SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED)) != 0 || 1924 (r = sshpkt_put_cstring(ssh, "open failed")) != 0 || 1925 (r = sshpkt_put_cstring(ssh, "")) != 0 || 1926 (r = sshpkt_send(ssh)) != 0) 1927 sshpkt_fatal(ssh, r, "%s: send failure", __func__); 1928 } 1929 r = 0; 1930 out: 1931 free(ctype); 1932 return r; 1933 } 1934 1935 static int 1936 client_input_channel_req(int type, u_int32_t seq, struct ssh *ssh) 1937 { 1938 Channel *c = NULL; 1939 char *rtype = NULL; 1940 u_char reply; 1941 u_int id, exitval; 1942 int r, success = 0; 1943 1944 if ((r = sshpkt_get_u32(ssh, &id)) != 0) 1945 return r; 1946 if (id <= INT_MAX) 1947 c = channel_lookup(ssh, id); 1948 if (channel_proxy_upstream(c, type, seq, ssh)) 1949 return 0; 1950 if ((r = sshpkt_get_cstring(ssh, &rtype, NULL)) != 0 || 1951 (r = sshpkt_get_u8(ssh, &reply)) != 0) 1952 goto out; 1953 1954 debug("client_input_channel_req: channel %u rtype %s reply %d", 1955 id, rtype, reply); 1956 1957 if (c == NULL) { 1958 error("client_input_channel_req: channel %d: " 1959 "unknown channel", id); 1960 } else if (strcmp(rtype, "eow@openssh.com") == 0) { 1961 if ((r = sshpkt_get_end(ssh)) != 0) 1962 goto out; 1963 chan_rcvd_eow(ssh, c); 1964 } else if (strcmp(rtype, "exit-status") == 0) { 1965 if ((r = sshpkt_get_u32(ssh, &exitval)) != 0) 1966 goto out; 1967 if (c->ctl_chan != -1) { 1968 mux_exit_message(ssh, c, exitval); 1969 success = 1; 1970 } else if ((int)id == session_ident) { 1971 /* Record exit value of local session */ 1972 success = 1; 1973 exit_status = exitval; 1974 } else { 1975 /* Probably for a mux channel that has already closed */ 1976 debug_f("no sink for exit-status on channel %d", 1977 id); 1978 } 1979 if ((r = sshpkt_get_end(ssh)) != 0) 1980 goto out; 1981 } 1982 if (reply && c != NULL && !(c->flags & CHAN_CLOSE_SENT)) { 1983 if (!c->have_remote_id) 1984 fatal_f("channel %d: no remote_id", c->self); 1985 if ((r = sshpkt_start(ssh, success ? 1986 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE)) != 0 || 1987 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1988 (r = sshpkt_send(ssh)) != 0) 1989 sshpkt_fatal(ssh, r, "%s: send failure", __func__); 1990 } 1991 r = 0; 1992 out: 1993 free(rtype); 1994 return r; 1995 } 1996 1997 struct hostkeys_update_ctx { 1998 /* The hostname and (optionally) IP address string for the server */ 1999 char *host_str, *ip_str; 2000 2001 /* 2002 * Keys received from the server and a flag for each indicating 2003 * whether they already exist in known_hosts. 2004 * keys_match is filled in by hostkeys_find() and later (for new 2005 * keys) by client_global_hostkeys_prove_confirm(). 2006 */ 2007 struct sshkey **keys; 2008 u_int *keys_match; /* mask of HKF_MATCH_* from hostfile.h */ 2009 int *keys_verified; /* flag for new keys verified by server */ 2010 size_t nkeys, nnew, nincomplete; /* total, new keys, incomplete match */ 2011 2012 /* 2013 * Keys that are in known_hosts, but were not present in the update 2014 * from the server (i.e. scheduled to be deleted). 2015 * Filled in by hostkeys_find(). 2016 */ 2017 struct sshkey **old_keys; 2018 size_t nold; 2019 2020 /* Various special cases. */ 2021 int complex_hostspec; /* wildcard or manual pattern-list host name */ 2022 int ca_available; /* saw CA key for this host */ 2023 int old_key_seen; /* saw old key with other name/addr */ 2024 int other_name_seen; /* saw key with other name/addr */ 2025 }; 2026 2027 static void 2028 hostkeys_update_ctx_free(struct hostkeys_update_ctx *ctx) 2029 { 2030 size_t i; 2031 2032 if (ctx == NULL) 2033 return; 2034 for (i = 0; i < ctx->nkeys; i++) 2035 sshkey_free(ctx->keys[i]); 2036 free(ctx->keys); 2037 free(ctx->keys_match); 2038 free(ctx->keys_verified); 2039 for (i = 0; i < ctx->nold; i++) 2040 sshkey_free(ctx->old_keys[i]); 2041 free(ctx->old_keys); 2042 free(ctx->host_str); 2043 free(ctx->ip_str); 2044 free(ctx); 2045 } 2046 2047 /* 2048 * Returns non-zero if a known_hosts hostname list is not of a form that 2049 * can be handled by UpdateHostkeys. These include wildcard hostnames and 2050 * hostnames lists that do not follow the form host[,ip]. 2051 */ 2052 static int 2053 hostspec_is_complex(const char *hosts) 2054 { 2055 char *cp; 2056 2057 /* wildcard */ 2058 if (strchr(hosts, '*') != NULL || strchr(hosts, '?') != NULL) 2059 return 1; 2060 /* single host/ip = ok */ 2061 if ((cp = strchr(hosts, ',')) == NULL) 2062 return 0; 2063 /* more than two entries on the line */ 2064 if (strchr(cp + 1, ',') != NULL) 2065 return 1; 2066 /* XXX maybe parse cp+1 and ensure it is an IP? */ 2067 return 0; 2068 } 2069 2070 /* callback to search for ctx->keys in known_hosts */ 2071 static int 2072 hostkeys_find(struct hostkey_foreach_line *l, void *_ctx) 2073 { 2074 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 2075 size_t i; 2076 struct sshkey **tmp; 2077 2078 if (l->key == NULL) 2079 return 0; 2080 if (l->status != HKF_STATUS_MATCHED) { 2081 /* Record if one of the keys appears on a non-matching line */ 2082 for (i = 0; i < ctx->nkeys; i++) { 2083 if (sshkey_equal(l->key, ctx->keys[i])) { 2084 ctx->other_name_seen = 1; 2085 debug3_f("found %s key under different " 2086 "name/addr at %s:%ld", 2087 sshkey_ssh_name(ctx->keys[i]), 2088 l->path, l->linenum); 2089 return 0; 2090 } 2091 } 2092 return 0; 2093 } 2094 /* Don't proceed if revocation or CA markers are present */ 2095 /* XXX relax this */ 2096 if (l->marker != MRK_NONE) { 2097 debug3_f("hostkeys file %s:%ld has CA/revocation marker", 2098 l->path, l->linenum); 2099 ctx->complex_hostspec = 1; 2100 return 0; 2101 } 2102 2103 /* If CheckHostIP is enabled, then check for mismatched hostname/addr */ 2104 if (ctx->ip_str != NULL && strchr(l->hosts, ',') != NULL) { 2105 if ((l->match & HKF_MATCH_HOST) == 0) { 2106 /* Record if address matched a different hostname. */ 2107 ctx->other_name_seen = 1; 2108 debug3_f("found address %s against different hostname " 2109 "at %s:%ld", ctx->ip_str, l->path, l->linenum); 2110 return 0; 2111 } else if ((l->match & HKF_MATCH_IP) == 0) { 2112 /* Record if hostname matched a different address. */ 2113 ctx->other_name_seen = 1; 2114 debug3_f("found hostname %s against different address " 2115 "at %s:%ld", ctx->host_str, l->path, l->linenum); 2116 } 2117 } 2118 2119 /* 2120 * UpdateHostkeys is skipped for wildcard host names and hostnames 2121 * that contain more than two entries (ssh never writes these). 2122 */ 2123 if (hostspec_is_complex(l->hosts)) { 2124 debug3_f("hostkeys file %s:%ld complex host specification", 2125 l->path, l->linenum); 2126 ctx->complex_hostspec = 1; 2127 return 0; 2128 } 2129 2130 /* Mark off keys we've already seen for this host */ 2131 for (i = 0; i < ctx->nkeys; i++) { 2132 if (!sshkey_equal(l->key, ctx->keys[i])) 2133 continue; 2134 debug3_f("found %s key at %s:%ld", 2135 sshkey_ssh_name(ctx->keys[i]), l->path, l->linenum); 2136 ctx->keys_match[i] |= l->match; 2137 return 0; 2138 } 2139 /* This line contained a key that not offered by the server */ 2140 debug3_f("deprecated %s key at %s:%ld", sshkey_ssh_name(l->key), 2141 l->path, l->linenum); 2142 if ((tmp = recallocarray(ctx->old_keys, ctx->nold, ctx->nold + 1, 2143 sizeof(*ctx->old_keys))) == NULL) 2144 fatal_f("recallocarray failed nold = %zu", ctx->nold); 2145 ctx->old_keys = tmp; 2146 ctx->old_keys[ctx->nold++] = l->key; 2147 l->key = NULL; 2148 2149 return 0; 2150 } 2151 2152 /* callback to search for ctx->old_keys in known_hosts under other names */ 2153 static int 2154 hostkeys_check_old(struct hostkey_foreach_line *l, void *_ctx) 2155 { 2156 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 2157 size_t i; 2158 int hashed; 2159 2160 /* only care about lines that *don't* match the active host spec */ 2161 if (l->status == HKF_STATUS_MATCHED || l->key == NULL) 2162 return 0; 2163 2164 hashed = l->match & (HKF_MATCH_HOST_HASHED|HKF_MATCH_IP_HASHED); 2165 for (i = 0; i < ctx->nold; i++) { 2166 if (!sshkey_equal(l->key, ctx->old_keys[i])) 2167 continue; 2168 debug3_f("found deprecated %s key at %s:%ld as %s", 2169 sshkey_ssh_name(ctx->old_keys[i]), l->path, l->linenum, 2170 hashed ? "[HASHED]" : l->hosts); 2171 ctx->old_key_seen = 1; 2172 break; 2173 } 2174 return 0; 2175 } 2176 2177 /* 2178 * Check known_hosts files for deprecated keys under other names. Returns 0 2179 * on success or -1 on failure. Updates ctx->old_key_seen if deprecated keys 2180 * exist under names other than the active hostname/IP. 2181 */ 2182 static int 2183 check_old_keys_othernames(struct hostkeys_update_ctx *ctx) 2184 { 2185 size_t i; 2186 int r; 2187 2188 debug2_f("checking for %zu deprecated keys", ctx->nold); 2189 for (i = 0; i < options.num_user_hostfiles; i++) { 2190 debug3_f("searching %s for %s / %s", 2191 options.user_hostfiles[i], ctx->host_str, 2192 ctx->ip_str ? ctx->ip_str : "(none)"); 2193 if ((r = hostkeys_foreach(options.user_hostfiles[i], 2194 hostkeys_check_old, ctx, ctx->host_str, ctx->ip_str, 2195 HKF_WANT_PARSE_KEY, 0)) != 0) { 2196 if (r == SSH_ERR_SYSTEM_ERROR && errno == ENOENT) { 2197 debug_f("hostkeys file %s does not exist", 2198 options.user_hostfiles[i]); 2199 continue; 2200 } 2201 error_fr(r, "hostkeys_foreach failed for %s", 2202 options.user_hostfiles[i]); 2203 return -1; 2204 } 2205 } 2206 return 0; 2207 } 2208 2209 static void 2210 hostkey_change_preamble(LogLevel loglevel) 2211 { 2212 do_log2(loglevel, "The server has updated its host keys."); 2213 do_log2(loglevel, "These changes were verified by the server's " 2214 "existing trusted key."); 2215 } 2216 2217 static void 2218 update_known_hosts(struct hostkeys_update_ctx *ctx) 2219 { 2220 int r, was_raw = 0, first = 1; 2221 int asking = options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK; 2222 LogLevel loglevel = asking ? SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_VERBOSE; 2223 char *fp, *response; 2224 size_t i; 2225 struct stat sb; 2226 2227 for (i = 0; i < ctx->nkeys; i++) { 2228 if (!ctx->keys_verified[i]) 2229 continue; 2230 if ((fp = sshkey_fingerprint(ctx->keys[i], 2231 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 2232 fatal_f("sshkey_fingerprint failed"); 2233 if (first && asking) 2234 hostkey_change_preamble(loglevel); 2235 do_log2(loglevel, "Learned new hostkey: %s %s", 2236 sshkey_type(ctx->keys[i]), fp); 2237 first = 0; 2238 free(fp); 2239 } 2240 for (i = 0; i < ctx->nold; i++) { 2241 if ((fp = sshkey_fingerprint(ctx->old_keys[i], 2242 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 2243 fatal_f("sshkey_fingerprint failed"); 2244 if (first && asking) 2245 hostkey_change_preamble(loglevel); 2246 do_log2(loglevel, "Deprecating obsolete hostkey: %s %s", 2247 sshkey_type(ctx->old_keys[i]), fp); 2248 first = 0; 2249 free(fp); 2250 } 2251 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) { 2252 if (get_saved_tio() != NULL) { 2253 leave_raw_mode(1); 2254 was_raw = 1; 2255 } 2256 response = NULL; 2257 for (i = 0; !quit_pending && i < 3; i++) { 2258 free(response); 2259 response = read_passphrase("Accept updated hostkeys? " 2260 "(yes/no): ", RP_ECHO); 2261 if (response != NULL && strcasecmp(response, "yes") == 0) 2262 break; 2263 else if (quit_pending || response == NULL || 2264 strcasecmp(response, "no") == 0) { 2265 options.update_hostkeys = 0; 2266 break; 2267 } else { 2268 do_log2(loglevel, "Please enter " 2269 "\"yes\" or \"no\""); 2270 } 2271 } 2272 if (quit_pending || i >= 3 || response == NULL) 2273 options.update_hostkeys = 0; 2274 free(response); 2275 if (was_raw) 2276 enter_raw_mode(1); 2277 } 2278 if (options.update_hostkeys == 0) 2279 return; 2280 /* 2281 * Now that all the keys are verified, we can go ahead and replace 2282 * them in known_hosts (assuming SSH_UPDATE_HOSTKEYS_ASK didn't 2283 * cancel the operation). 2284 */ 2285 for (i = 0; i < options.num_user_hostfiles; i++) { 2286 /* 2287 * NB. keys are only added to hostfiles[0], for the rest we 2288 * just delete the hostname entries. 2289 */ 2290 if (stat(options.user_hostfiles[i], &sb) != 0) { 2291 if (errno == ENOENT) { 2292 debug_f("known hosts file %s does not " 2293 "exist", options.user_hostfiles[i]); 2294 } else { 2295 error_f("known hosts file %s " 2296 "inaccessible: %s", 2297 options.user_hostfiles[i], strerror(errno)); 2298 } 2299 continue; 2300 } 2301 if ((r = hostfile_replace_entries(options.user_hostfiles[i], 2302 ctx->host_str, ctx->ip_str, 2303 i == 0 ? ctx->keys : NULL, i == 0 ? ctx->nkeys : 0, 2304 options.hash_known_hosts, 0, 2305 options.fingerprint_hash)) != 0) { 2306 error_fr(r, "hostfile_replace_entries failed for %s", 2307 options.user_hostfiles[i]); 2308 } 2309 } 2310 } 2311 2312 static void 2313 client_global_hostkeys_prove_confirm(struct ssh *ssh, int type, 2314 u_int32_t seq, void *_ctx) 2315 { 2316 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 2317 size_t i, ndone; 2318 struct sshbuf *signdata; 2319 int r, plaintype; 2320 const u_char *sig; 2321 const char *rsa_kexalg = NULL; 2322 char *alg = NULL; 2323 size_t siglen; 2324 2325 if (ctx->nnew == 0) 2326 fatal_f("ctx->nnew == 0"); /* sanity */ 2327 if (type != SSH2_MSG_REQUEST_SUCCESS) { 2328 error("Server failed to confirm ownership of " 2329 "private host keys"); 2330 hostkeys_update_ctx_free(ctx); 2331 return; 2332 } 2333 if (sshkey_type_plain(sshkey_type_from_name( 2334 ssh->kex->hostkey_alg)) == KEY_RSA) 2335 rsa_kexalg = ssh->kex->hostkey_alg; 2336 if ((signdata = sshbuf_new()) == NULL) 2337 fatal_f("sshbuf_new failed"); 2338 /* 2339 * Expect a signature for each of the ctx->nnew private keys we 2340 * haven't seen before. They will be in the same order as the 2341 * ctx->keys where the corresponding ctx->keys_match[i] == 0. 2342 */ 2343 for (ndone = i = 0; i < ctx->nkeys; i++) { 2344 if (ctx->keys_match[i]) 2345 continue; 2346 plaintype = sshkey_type_plain(ctx->keys[i]->type); 2347 /* Prepare data to be signed: session ID, unique string, key */ 2348 sshbuf_reset(signdata); 2349 if ( (r = sshbuf_put_cstring(signdata, 2350 "hostkeys-prove-00@openssh.com")) != 0 || 2351 (r = sshbuf_put_stringb(signdata, 2352 ssh->kex->session_id)) != 0 || 2353 (r = sshkey_puts(ctx->keys[i], signdata)) != 0) 2354 fatal_fr(r, "compose signdata"); 2355 /* Extract and verify signature */ 2356 if ((r = sshpkt_get_string_direct(ssh, &sig, &siglen)) != 0) { 2357 error_fr(r, "parse sig"); 2358 goto out; 2359 } 2360 if ((r = sshkey_get_sigtype(sig, siglen, &alg)) != 0) { 2361 error_fr(r, "server gave unintelligible signature " 2362 "for %s key %zu", sshkey_type(ctx->keys[i]), i); 2363 goto out; 2364 } 2365 /* 2366 * Special case for RSA keys: if a RSA hostkey was negotiated, 2367 * then use its signature type for verification of RSA hostkey 2368 * proofs. Otherwise, accept only RSA-SHA256/512 signatures. 2369 */ 2370 if (plaintype == KEY_RSA && rsa_kexalg == NULL && 2371 match_pattern_list(alg, HOSTKEY_PROOF_RSA_ALGS, 0) != 1) { 2372 debug_f("server used untrusted RSA signature algorithm " 2373 "%s for key %zu, disregarding", alg, i); 2374 free(alg); 2375 /* zap the key from the list */ 2376 sshkey_free(ctx->keys[i]); 2377 ctx->keys[i] = NULL; 2378 ndone++; 2379 continue; 2380 } 2381 debug3_f("verify %s key %zu using sigalg %s", 2382 sshkey_type(ctx->keys[i]), i, alg); 2383 free(alg); 2384 if ((r = sshkey_verify(ctx->keys[i], sig, siglen, 2385 sshbuf_ptr(signdata), sshbuf_len(signdata), 2386 plaintype == KEY_RSA ? rsa_kexalg : NULL, 0, NULL)) != 0) { 2387 error_fr(r, "server gave bad signature for %s key %zu", 2388 sshkey_type(ctx->keys[i]), i); 2389 goto out; 2390 } 2391 /* Key is good. Mark it as 'seen' */ 2392 ctx->keys_verified[i] = 1; 2393 ndone++; 2394 } 2395 /* Shouldn't happen */ 2396 if (ndone != ctx->nnew) 2397 fatal_f("ndone != ctx->nnew (%zu / %zu)", ndone, ctx->nnew); 2398 if ((r = sshpkt_get_end(ssh)) != 0) { 2399 error_f("protocol error"); 2400 goto out; 2401 } 2402 2403 /* Make the edits to known_hosts */ 2404 update_known_hosts(ctx); 2405 out: 2406 hostkeys_update_ctx_free(ctx); 2407 hostkeys_update_complete = 1; 2408 client_repledge(); 2409 } 2410 2411 /* 2412 * Handle hostkeys-00@openssh.com global request to inform the client of all 2413 * the server's hostkeys. The keys are checked against the user's 2414 * HostkeyAlgorithms preference before they are accepted. 2415 */ 2416 static int 2417 client_input_hostkeys(struct ssh *ssh) 2418 { 2419 const u_char *blob = NULL; 2420 size_t i, len = 0; 2421 struct sshbuf *buf = NULL; 2422 struct sshkey *key = NULL, **tmp; 2423 int r, prove_sent = 0; 2424 char *fp; 2425 static int hostkeys_seen = 0; /* XXX use struct ssh */ 2426 extern struct sockaddr_storage hostaddr; /* XXX from ssh.c */ 2427 struct hostkeys_update_ctx *ctx = NULL; 2428 u_int want; 2429 2430 if (hostkeys_seen) 2431 fatal_f("server already sent hostkeys"); 2432 if (!can_update_hostkeys()) 2433 return 1; 2434 hostkeys_seen = 1; 2435 2436 ctx = xcalloc(1, sizeof(*ctx)); 2437 while (ssh_packet_remaining(ssh) > 0) { 2438 sshkey_free(key); 2439 key = NULL; 2440 if ((r = sshpkt_get_string_direct(ssh, &blob, &len)) != 0) { 2441 error_fr(r, "parse key"); 2442 goto out; 2443 } 2444 if ((r = sshkey_from_blob(blob, len, &key)) != 0) { 2445 do_log2_fr(r, r == SSH_ERR_KEY_TYPE_UNKNOWN ? 2446 SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_ERROR, 2447 "convert key"); 2448 continue; 2449 } 2450 fp = sshkey_fingerprint(key, options.fingerprint_hash, 2451 SSH_FP_DEFAULT); 2452 debug3_f("received %s key %s", sshkey_type(key), fp); 2453 free(fp); 2454 2455 if (!hostkey_accepted_by_hostkeyalgs(key)) { 2456 debug3_f("%s key not permitted by " 2457 "HostkeyAlgorithms", sshkey_ssh_name(key)); 2458 continue; 2459 } 2460 /* Skip certs */ 2461 if (sshkey_is_cert(key)) { 2462 debug3_f("%s key is a certificate; skipping", 2463 sshkey_ssh_name(key)); 2464 continue; 2465 } 2466 /* Ensure keys are unique */ 2467 for (i = 0; i < ctx->nkeys; i++) { 2468 if (sshkey_equal(key, ctx->keys[i])) { 2469 error_f("received duplicated %s host key", 2470 sshkey_ssh_name(key)); 2471 goto out; 2472 } 2473 } 2474 /* Key is good, record it */ 2475 if ((tmp = recallocarray(ctx->keys, ctx->nkeys, ctx->nkeys + 1, 2476 sizeof(*ctx->keys))) == NULL) 2477 fatal_f("recallocarray failed nkeys = %zu", 2478 ctx->nkeys); 2479 ctx->keys = tmp; 2480 ctx->keys[ctx->nkeys++] = key; 2481 key = NULL; 2482 } 2483 2484 if (ctx->nkeys == 0) { 2485 debug_f("server sent no hostkeys"); 2486 goto out; 2487 } 2488 2489 if ((ctx->keys_match = calloc(ctx->nkeys, 2490 sizeof(*ctx->keys_match))) == NULL || 2491 (ctx->keys_verified = calloc(ctx->nkeys, 2492 sizeof(*ctx->keys_verified))) == NULL) 2493 fatal_f("calloc failed"); 2494 2495 get_hostfile_hostname_ipaddr(host, 2496 options.check_host_ip ? (struct sockaddr *)&hostaddr : NULL, 2497 options.port, &ctx->host_str, 2498 options.check_host_ip ? &ctx->ip_str : NULL); 2499 2500 /* Find which keys we already know about. */ 2501 for (i = 0; i < options.num_user_hostfiles; i++) { 2502 debug_f("searching %s for %s / %s", 2503 options.user_hostfiles[i], ctx->host_str, 2504 ctx->ip_str ? ctx->ip_str : "(none)"); 2505 if ((r = hostkeys_foreach(options.user_hostfiles[i], 2506 hostkeys_find, ctx, ctx->host_str, ctx->ip_str, 2507 HKF_WANT_PARSE_KEY, 0)) != 0) { 2508 if (r == SSH_ERR_SYSTEM_ERROR && errno == ENOENT) { 2509 debug_f("hostkeys file %s does not exist", 2510 options.user_hostfiles[i]); 2511 continue; 2512 } 2513 error_fr(r, "hostkeys_foreach failed for %s", 2514 options.user_hostfiles[i]); 2515 goto out; 2516 } 2517 } 2518 2519 /* Figure out if we have any new keys to add */ 2520 ctx->nnew = ctx->nincomplete = 0; 2521 want = HKF_MATCH_HOST | ( options.check_host_ip ? HKF_MATCH_IP : 0); 2522 for (i = 0; i < ctx->nkeys; i++) { 2523 if (ctx->keys_match[i] == 0) 2524 ctx->nnew++; 2525 if ((ctx->keys_match[i] & want) != want) 2526 ctx->nincomplete++; 2527 } 2528 2529 debug3_f("%zu server keys: %zu new, %zu retained, " 2530 "%zu incomplete match. %zu to remove", ctx->nkeys, ctx->nnew, 2531 ctx->nkeys - ctx->nnew - ctx->nincomplete, 2532 ctx->nincomplete, ctx->nold); 2533 2534 if (ctx->nnew == 0 && ctx->nold == 0) { 2535 debug_f("no new or deprecated keys from server"); 2536 goto out; 2537 } 2538 2539 /* Various reasons why we cannot proceed with the update */ 2540 if (ctx->complex_hostspec) { 2541 debug_f("CA/revocation marker, manual host list or wildcard " 2542 "host pattern found, skipping UserKnownHostsFile update"); 2543 goto out; 2544 } 2545 if (ctx->other_name_seen) { 2546 debug_f("host key found matching a different name/address, " 2547 "skipping UserKnownHostsFile update"); 2548 goto out; 2549 } 2550 /* 2551 * If removing keys, check whether they appear under different 2552 * names/addresses and refuse to proceed if they do. This avoids 2553 * cases such as hosts with multiple names becoming inconsistent 2554 * with regards to CheckHostIP entries. 2555 * XXX UpdateHostkeys=force to override this (and other) checks? 2556 */ 2557 if (ctx->nold != 0) { 2558 if (check_old_keys_othernames(ctx) != 0) 2559 goto out; /* error already logged */ 2560 if (ctx->old_key_seen) { 2561 debug_f("key(s) for %s%s%s exist under other names; " 2562 "skipping UserKnownHostsFile update", 2563 ctx->host_str, ctx->ip_str == NULL ? "" : ",", 2564 ctx->ip_str == NULL ? "" : ctx->ip_str); 2565 goto out; 2566 } 2567 } 2568 2569 if (ctx->nnew == 0) { 2570 /* 2571 * We have some keys to remove or fix matching for. 2572 * We can proceed to do this without requiring a fresh proof 2573 * from the server. 2574 */ 2575 update_known_hosts(ctx); 2576 goto out; 2577 } 2578 /* 2579 * We have received previously-unseen keys from the server. 2580 * Ask the server to confirm ownership of the private halves. 2581 */ 2582 debug3_f("asking server to prove ownership for %zu keys", ctx->nnew); 2583 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 2584 (r = sshpkt_put_cstring(ssh, 2585 "hostkeys-prove-00@openssh.com")) != 0 || 2586 (r = sshpkt_put_u8(ssh, 1)) != 0) /* bool: want reply */ 2587 fatal_fr(r, "prepare hostkeys-prove"); 2588 if ((buf = sshbuf_new()) == NULL) 2589 fatal_f("sshbuf_new"); 2590 for (i = 0; i < ctx->nkeys; i++) { 2591 if (ctx->keys_match[i]) 2592 continue; 2593 sshbuf_reset(buf); 2594 if ((r = sshkey_putb(ctx->keys[i], buf)) != 0 || 2595 (r = sshpkt_put_stringb(ssh, buf)) != 0) 2596 fatal_fr(r, "assemble hostkeys-prove"); 2597 } 2598 if ((r = sshpkt_send(ssh)) != 0) 2599 fatal_fr(r, "send hostkeys-prove"); 2600 client_register_global_confirm( 2601 client_global_hostkeys_prove_confirm, ctx); 2602 ctx = NULL; /* will be freed in callback */ 2603 prove_sent = 1; 2604 2605 /* Success */ 2606 out: 2607 hostkeys_update_ctx_free(ctx); 2608 sshkey_free(key); 2609 sshbuf_free(buf); 2610 if (!prove_sent) { 2611 /* UpdateHostkeys handling completed */ 2612 hostkeys_update_complete = 1; 2613 client_repledge(); 2614 } 2615 /* 2616 * NB. Return success for all cases. The server doesn't need to know 2617 * what the client does with its hosts file. 2618 */ 2619 return 1; 2620 } 2621 2622 static int 2623 client_input_global_request(int type, u_int32_t seq, struct ssh *ssh) 2624 { 2625 char *rtype; 2626 u_char want_reply; 2627 int r, success = 0; 2628 2629 if ((r = sshpkt_get_cstring(ssh, &rtype, NULL)) != 0 || 2630 (r = sshpkt_get_u8(ssh, &want_reply)) != 0) 2631 goto out; 2632 debug("client_input_global_request: rtype %s want_reply %d", 2633 rtype, want_reply); 2634 if (strcmp(rtype, "hostkeys-00@openssh.com") == 0) 2635 success = client_input_hostkeys(ssh); 2636 if (want_reply) { 2637 if ((r = sshpkt_start(ssh, success ? SSH2_MSG_REQUEST_SUCCESS : 2638 SSH2_MSG_REQUEST_FAILURE)) != 0 || 2639 (r = sshpkt_send(ssh)) != 0 || 2640 (r = ssh_packet_write_wait(ssh)) != 0) 2641 goto out; 2642 } 2643 r = 0; 2644 out: 2645 free(rtype); 2646 return r; 2647 } 2648 2649 static void 2650 client_send_env(struct ssh *ssh, int id, const char *name, const char *val) 2651 { 2652 int r; 2653 2654 debug("channel %d: setting env %s = \"%s\"", id, name, val); 2655 channel_request_start(ssh, id, "env", 0); 2656 if ((r = sshpkt_put_cstring(ssh, name)) != 0 || 2657 (r = sshpkt_put_cstring(ssh, val)) != 0 || 2658 (r = sshpkt_send(ssh)) != 0) 2659 fatal_fr(r, "send setenv"); 2660 } 2661 2662 void 2663 client_session2_setup(struct ssh *ssh, int id, int want_tty, int want_subsystem, 2664 const char *term, struct termios *tiop, int in_fd, struct sshbuf *cmd, 2665 char **env) 2666 { 2667 size_t i, j, len; 2668 int matched, r; 2669 char *name, *val; 2670 Channel *c = NULL; 2671 2672 debug2_f("id %d", id); 2673 2674 if ((c = channel_lookup(ssh, id)) == NULL) 2675 fatal_f("channel %d: unknown channel", id); 2676 2677 ssh_packet_set_interactive(ssh, want_tty, 2678 options.ip_qos_interactive, options.ip_qos_bulk); 2679 2680 if (want_tty) { 2681 struct winsize ws; 2682 2683 /* Store window size in the packet. */ 2684 if (ioctl(in_fd, TIOCGWINSZ, &ws) == -1) 2685 memset(&ws, 0, sizeof(ws)); 2686 2687 channel_request_start(ssh, id, "pty-req", 1); 2688 client_expect_confirm(ssh, id, "PTY allocation", CONFIRM_TTY); 2689 if ((r = sshpkt_put_cstring(ssh, term != NULL ? term : "")) 2690 != 0 || 2691 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || 2692 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || 2693 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || 2694 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0) 2695 fatal_fr(r, "build pty-req"); 2696 if (tiop == NULL) 2697 tiop = get_saved_tio(); 2698 ssh_tty_make_modes(ssh, -1, tiop); 2699 if ((r = sshpkt_send(ssh)) != 0) 2700 fatal_fr(r, "send pty-req"); 2701 /* XXX wait for reply */ 2702 c->client_tty = 1; 2703 } 2704 2705 /* Transfer any environment variables from client to server */ 2706 if (options.num_send_env != 0 && env != NULL) { 2707 debug("Sending environment."); 2708 for (i = 0; env[i] != NULL; i++) { 2709 /* Split */ 2710 name = xstrdup(env[i]); 2711 if ((val = strchr(name, '=')) == NULL) { 2712 free(name); 2713 continue; 2714 } 2715 *val++ = '\0'; 2716 2717 matched = 0; 2718 for (j = 0; j < options.num_send_env; j++) { 2719 if (match_pattern(name, options.send_env[j])) { 2720 matched = 1; 2721 break; 2722 } 2723 } 2724 if (!matched) { 2725 debug3("Ignored env %s", name); 2726 free(name); 2727 continue; 2728 } 2729 client_send_env(ssh, id, name, val); 2730 free(name); 2731 } 2732 } 2733 for (i = 0; i < options.num_setenv; i++) { 2734 /* Split */ 2735 name = xstrdup(options.setenv[i]); 2736 if ((val = strchr(name, '=')) == NULL) { 2737 free(name); 2738 continue; 2739 } 2740 *val++ = '\0'; 2741 client_send_env(ssh, id, name, val); 2742 free(name); 2743 } 2744 2745 len = sshbuf_len(cmd); 2746 if (len > 0) { 2747 if (len > 900) 2748 len = 900; 2749 if (want_subsystem) { 2750 debug("Sending subsystem: %.*s", 2751 (int)len, (const u_char*)sshbuf_ptr(cmd)); 2752 channel_request_start(ssh, id, "subsystem", 1); 2753 client_expect_confirm(ssh, id, "subsystem", 2754 CONFIRM_CLOSE); 2755 } else { 2756 debug("Sending command: %.*s", 2757 (int)len, (const u_char*)sshbuf_ptr(cmd)); 2758 channel_request_start(ssh, id, "exec", 1); 2759 client_expect_confirm(ssh, id, "exec", CONFIRM_CLOSE); 2760 } 2761 if ((r = sshpkt_put_stringb(ssh, cmd)) != 0 || 2762 (r = sshpkt_send(ssh)) != 0) 2763 fatal_fr(r, "send command"); 2764 } else { 2765 channel_request_start(ssh, id, "shell", 1); 2766 client_expect_confirm(ssh, id, "shell", CONFIRM_CLOSE); 2767 if ((r = sshpkt_send(ssh)) != 0) 2768 fatal_fr(r, "send shell"); 2769 } 2770 2771 session_setup_complete = 1; 2772 client_repledge(); 2773 } 2774 2775 static void 2776 client_init_dispatch(struct ssh *ssh) 2777 { 2778 ssh_dispatch_init(ssh, &dispatch_protocol_error); 2779 2780 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); 2781 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_DATA, &channel_input_data); 2782 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); 2783 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); 2784 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open); 2785 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 2786 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 2787 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req); 2788 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); 2789 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm); 2790 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm); 2791 ssh_dispatch_set(ssh, SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request); 2792 2793 /* rekeying */ 2794 ssh_dispatch_set(ssh, SSH2_MSG_KEXINIT, &kex_input_kexinit); 2795 2796 /* global request reply messages */ 2797 ssh_dispatch_set(ssh, SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply); 2798 ssh_dispatch_set(ssh, SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply); 2799 } 2800 2801 void 2802 client_stop_mux(void) 2803 { 2804 if (options.control_path != NULL && muxserver_sock != -1) 2805 unlink(options.control_path); 2806 /* 2807 * If we are in persist mode, or don't have a shell, signal that we 2808 * should close when all active channels are closed. 2809 */ 2810 if (options.control_persist || options.session_type == SESSION_TYPE_NONE) { 2811 session_closed = 1; 2812 setproctitle("[stopped mux]"); 2813 } 2814 } 2815 2816 /* client specific fatal cleanup */ 2817 void 2818 cleanup_exit(int i) 2819 { 2820 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 2821 if (options.control_path != NULL && muxserver_sock != -1) 2822 unlink(options.control_path); 2823 ssh_kill_proxy_command(); 2824 _exit(i); 2825 } 2826