1 /* $OpenBSD: clientloop.c,v 1.408 2024/07/01 04:31:17 djm Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * The main loop for the interactive session (client side). 7 * 8 * As far as I am concerned, the code I have written for this software 9 * can be used freely for any purpose. Any derived versions of this 10 * software must be clearly marked as such, and if the derived work is 11 * incompatible with the protocol description in the RFC file, it must be 12 * called by a name other than "ssh" or "Secure Shell". 13 * 14 * 15 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 16 * 17 * Redistribution and use in source and binary forms, with or without 18 * modification, are permitted provided that the following conditions 19 * are met: 20 * 1. Redistributions of source code must retain the above copyright 21 * notice, this list of conditions and the following disclaimer. 22 * 2. Redistributions in binary form must reproduce the above copyright 23 * notice, this list of conditions and the following disclaimer in the 24 * documentation and/or other materials provided with the distribution. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 27 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 28 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 29 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 30 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 31 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 35 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 36 * 37 * 38 * SSH2 support added by Markus Friedl. 39 * Copyright (c) 1999, 2000, 2001 Markus Friedl. All rights reserved. 40 * 41 * Redistribution and use in source and binary forms, with or without 42 * modification, are permitted provided that the following conditions 43 * are met: 44 * 1. Redistributions of source code must retain the above copyright 45 * notice, this list of conditions and the following disclaimer. 46 * 2. Redistributions in binary form must reproduce the above copyright 47 * notice, this list of conditions and the following disclaimer in the 48 * documentation and/or other materials provided with the distribution. 49 * 50 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 51 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 52 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 53 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 54 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 55 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 56 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 57 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 58 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 59 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 60 */ 61 62 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 !ssh_packet_have_data_to_write(ssh)) { 603 /* If due to send but have no data, then send chaff */ 604 if (send_chaff(ssh)) 605 nchaff++; 606 } 607 } 608 609 if (stop_reason != NULL) { 610 if (active) { 611 debug3_f("stopping: %s (%llu chaff packets sent)", 612 stop_reason, nchaff); 613 active = 0; 614 } 615 return 1; 616 } 617 618 /* 619 * If we're in interactive mode, and only have a small amount 620 * of outbound data, then we assume that the user is typing 621 * interactively. In this case, start quantising outbound packets to 622 * fixed time intervals to hide inter-keystroke timing. 623 */ 624 if (!active && ssh_packet_interactive_data_to_write(ssh) && 625 channel_did_enqueue && ssh_packet_have_data_to_write(ssh)) { 626 debug3_f("starting: interval ~%dms", 627 options.obscure_keystroke_timing_interval); 628 just_started = had_keystroke = active = 1; 629 nchaff = 0; 630 set_next_interval(&now, &next_interval, 631 options.obscure_keystroke_timing_interval, 1); 632 } 633 634 /* Don't hold off if obfuscation inactive */ 635 if (!active) 636 return 1; 637 638 if (had_keystroke) { 639 /* 640 * Arrange to send chaff packets for a random interval after 641 * the last keystroke was sent. 642 */ 643 ms_to_timespec(&tmp, SSH_KEYSTROKE_CHAFF_MIN_MS + 644 arc4random_uniform(SSH_KEYSTROKE_CHAFF_RNG_MS)); 645 timespecadd(&now, &tmp, &chaff_until); 646 } 647 648 ptimeout_deadline_monotime_tsp(timeout, &next_interval); 649 650 if (just_started) 651 return 1; 652 653 /* Don't arm output fd for poll until the timing interval has elapsed */ 654 if (timespeccmp(&now, &next_interval, <)) 655 return 0; 656 657 /* Calculate number of intervals missed since the last check */ 658 n = (now.tv_sec - next_interval.tv_sec) * 1000LL * 1000 * 1000; 659 n += now.tv_nsec - next_interval.tv_nsec; 660 n /= options.obscure_keystroke_timing_interval * 1000LL * 1000; 661 n = (n < 0) ? 1 : n + 1; 662 663 /* Advance to the next interval */ 664 set_next_interval(&now, &next_interval, 665 options.obscure_keystroke_timing_interval * n, 0); 666 return 1; 667 } 668 669 /* 670 * Waits until the client can do something (some data becomes available on 671 * one of the file descriptors). 672 */ 673 static void 674 client_wait_until_can_do_something(struct ssh *ssh, struct pollfd **pfdp, 675 u_int *npfd_allocp, u_int *npfd_activep, int channel_did_enqueue, 676 sigset_t *sigsetp, int *conn_in_readyp, int *conn_out_readyp) 677 { 678 struct timespec timeout; 679 int ret, oready; 680 u_int p; 681 682 *conn_in_readyp = *conn_out_readyp = 0; 683 684 /* Prepare channel poll. First two pollfd entries are reserved */ 685 ptimeout_init(&timeout); 686 channel_prepare_poll(ssh, pfdp, npfd_allocp, npfd_activep, 2, &timeout); 687 if (*npfd_activep < 2) 688 fatal_f("bad npfd %u", *npfd_activep); /* shouldn't happen */ 689 690 /* channel_prepare_poll could have closed the last channel */ 691 if (session_closed && !channel_still_open(ssh) && 692 !ssh_packet_have_data_to_write(ssh)) { 693 /* clear events since we did not call poll() */ 694 for (p = 0; p < *npfd_activep; p++) 695 (*pfdp)[p].revents = 0; 696 return; 697 } 698 699 oready = obfuscate_keystroke_timing(ssh, &timeout, channel_did_enqueue); 700 701 /* Monitor server connection on reserved pollfd entries */ 702 (*pfdp)[0].fd = connection_in; 703 (*pfdp)[0].events = POLLIN; 704 (*pfdp)[1].fd = connection_out; 705 (*pfdp)[1].events = (oready && ssh_packet_have_data_to_write(ssh)) ? 706 POLLOUT : 0; 707 708 /* 709 * Wait for something to happen. This will suspend the process until 710 * some polled descriptor can be read, written, or has some other 711 * event pending, or a timeout expires. 712 */ 713 set_control_persist_exit_time(ssh); 714 if (control_persist_exit_time > 0) 715 ptimeout_deadline_monotime(&timeout, control_persist_exit_time); 716 if (options.server_alive_interval > 0) 717 ptimeout_deadline_monotime(&timeout, server_alive_time); 718 if (options.rekey_interval > 0 && !ssh_packet_is_rekeying(ssh)) { 719 ptimeout_deadline_sec(&timeout, 720 ssh_packet_get_rekey_timeout(ssh)); 721 } 722 723 ret = ppoll(*pfdp, *npfd_activep, ptimeout_get_tsp(&timeout), sigsetp); 724 725 if (ret == -1) { 726 /* 727 * We have to clear the events because we return. 728 * We have to return, because the mainloop checks for the flags 729 * set by the signal handlers. 730 */ 731 for (p = 0; p < *npfd_activep; p++) 732 (*pfdp)[p].revents = 0; 733 if (errno == EINTR) 734 return; 735 /* Note: we might still have data in the buffers. */ 736 quit_message("poll: %s", strerror(errno)); 737 return; 738 } 739 740 *conn_in_readyp = (*pfdp)[0].revents != 0; 741 *conn_out_readyp = (*pfdp)[1].revents != 0; 742 743 if (options.server_alive_interval > 0 && !*conn_in_readyp && 744 monotime() >= server_alive_time) { 745 /* 746 * ServerAlive check is needed. We can't rely on the poll 747 * timing out since traffic on the client side such as port 748 * forwards can keep waking it up. 749 */ 750 server_alive_check(ssh); 751 } 752 } 753 754 static void 755 client_suspend_self(struct sshbuf *bin, struct sshbuf *bout, struct sshbuf *berr) 756 { 757 /* Flush stdout and stderr buffers. */ 758 if (sshbuf_len(bout) > 0) 759 atomicio(vwrite, fileno(stdout), sshbuf_mutable_ptr(bout), 760 sshbuf_len(bout)); 761 if (sshbuf_len(berr) > 0) 762 atomicio(vwrite, fileno(stderr), sshbuf_mutable_ptr(berr), 763 sshbuf_len(berr)); 764 765 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 766 767 sshbuf_reset(bin); 768 sshbuf_reset(bout); 769 sshbuf_reset(berr); 770 771 /* Send the suspend signal to the program itself. */ 772 kill(getpid(), SIGTSTP); 773 774 /* Reset window sizes in case they have changed */ 775 received_window_change_signal = 1; 776 777 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 778 } 779 780 static void 781 client_process_net_input(struct ssh *ssh) 782 { 783 int r; 784 785 /* 786 * Read input from the server, and add any such data to the buffer of 787 * the packet subsystem. 788 */ 789 schedule_server_alive_check(); 790 if ((r = ssh_packet_process_read(ssh, connection_in)) == 0) 791 return; /* success */ 792 if (r == SSH_ERR_SYSTEM_ERROR) { 793 if (errno == EAGAIN || errno == EINTR) 794 return; 795 if (errno == EPIPE) { 796 quit_message("Connection to %s closed by remote host.", 797 host); 798 return; 799 } 800 } 801 quit_message("Read from remote host %s: %s", host, ssh_err(r)); 802 } 803 804 static void 805 client_status_confirm(struct ssh *ssh, int type, Channel *c, void *ctx) 806 { 807 struct channel_reply_ctx *cr = (struct channel_reply_ctx *)ctx; 808 char errmsg[256]; 809 int r, tochan; 810 811 /* 812 * If a TTY was explicitly requested, then a failure to allocate 813 * one is fatal. 814 */ 815 if (cr->action == CONFIRM_TTY && 816 (options.request_tty == REQUEST_TTY_FORCE || 817 options.request_tty == REQUEST_TTY_YES)) 818 cr->action = CONFIRM_CLOSE; 819 820 /* XXX suppress on mux _client_ quietmode */ 821 tochan = options.log_level >= SYSLOG_LEVEL_ERROR && 822 c->ctl_chan != -1 && c->extended_usage == CHAN_EXTENDED_WRITE; 823 824 if (type == SSH2_MSG_CHANNEL_SUCCESS) { 825 debug2("%s request accepted on channel %d", 826 cr->request_type, c->self); 827 } else if (type == SSH2_MSG_CHANNEL_FAILURE) { 828 if (tochan) { 829 snprintf(errmsg, sizeof(errmsg), 830 "%s request failed\r\n", cr->request_type); 831 } else { 832 snprintf(errmsg, sizeof(errmsg), 833 "%s request failed on channel %d", 834 cr->request_type, c->self); 835 } 836 /* If error occurred on primary session channel, then exit */ 837 if (cr->action == CONFIRM_CLOSE && c->self == session_ident) 838 fatal("%s", errmsg); 839 /* 840 * If error occurred on mux client, append to 841 * their stderr. 842 */ 843 if (tochan) { 844 debug3_f("channel %d: mux request: %s", c->self, 845 cr->request_type); 846 if ((r = sshbuf_put(c->extended, errmsg, 847 strlen(errmsg))) != 0) 848 fatal_fr(r, "sshbuf_put"); 849 } else 850 error("%s", errmsg); 851 if (cr->action == CONFIRM_TTY) { 852 /* 853 * If a TTY allocation error occurred, then arrange 854 * for the correct TTY to leave raw mode. 855 */ 856 if (c->self == session_ident) 857 leave_raw_mode(0); 858 else 859 mux_tty_alloc_failed(ssh, c); 860 } else if (cr->action == CONFIRM_CLOSE) { 861 chan_read_failed(ssh, c); 862 chan_write_failed(ssh, c); 863 } 864 } 865 free(cr); 866 } 867 868 static void 869 client_abandon_status_confirm(struct ssh *ssh, Channel *c, void *ctx) 870 { 871 free(ctx); 872 } 873 874 void 875 client_expect_confirm(struct ssh *ssh, int id, const char *request, 876 enum confirm_action action) 877 { 878 struct channel_reply_ctx *cr = xcalloc(1, sizeof(*cr)); 879 880 cr->request_type = request; 881 cr->action = action; 882 883 channel_register_status_confirm(ssh, id, client_status_confirm, 884 client_abandon_status_confirm, cr); 885 } 886 887 void 888 client_register_global_confirm(global_confirm_cb *cb, void *ctx) 889 { 890 struct global_confirm *gc, *last_gc; 891 892 /* Coalesce identical callbacks */ 893 last_gc = TAILQ_LAST(&global_confirms, global_confirms); 894 if (last_gc && last_gc->cb == cb && last_gc->ctx == ctx) { 895 if (++last_gc->ref_count >= INT_MAX) 896 fatal_f("last_gc->ref_count = %d", 897 last_gc->ref_count); 898 return; 899 } 900 901 gc = xcalloc(1, sizeof(*gc)); 902 gc->cb = cb; 903 gc->ctx = ctx; 904 gc->ref_count = 1; 905 TAILQ_INSERT_TAIL(&global_confirms, gc, entry); 906 } 907 908 /* 909 * Returns non-zero if the client is able to handle a hostkeys-00@openssh.com 910 * hostkey update request. 911 */ 912 static int 913 can_update_hostkeys(void) 914 { 915 if (hostkeys_update_complete) 916 return 0; 917 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK && 918 options.batch_mode) 919 return 0; /* won't ask in batchmode, so don't even try */ 920 if (!options.update_hostkeys || options.num_user_hostfiles <= 0) 921 return 0; 922 return 1; 923 } 924 925 static void 926 client_repledge(void) 927 { 928 debug3_f("enter"); 929 930 /* Might be able to tighten pledge now that session is established */ 931 if (options.control_master || options.control_path != NULL || 932 options.forward_x11 || options.fork_after_authentication || 933 can_update_hostkeys() || 934 (session_ident != -1 && !session_setup_complete)) { 935 /* Can't tighten */ 936 return; 937 } 938 /* 939 * LocalCommand and UpdateHostkeys have finished, so can get rid of 940 * filesystem. 941 * 942 * XXX protocol allows a server can to change hostkeys during the 943 * connection at rekey time that could trigger a hostkeys update 944 * but AFAIK no implementations support this. Could improve by 945 * forcing known_hosts to be read-only or via unveil(2). 946 */ 947 if (options.num_local_forwards != 0 || 948 options.num_remote_forwards != 0 || 949 options.num_permitted_remote_opens != 0 || 950 options.enable_escape_commandline != 0) { 951 /* rfwd needs inet */ 952 debug("pledge: network"); 953 if (pledge("stdio unix inet dns proc tty", NULL) == -1) 954 fatal_f("pledge(): %s", strerror(errno)); 955 } else if (options.forward_agent != 0) { 956 /* agent forwarding needs to open $SSH_AUTH_SOCK at will */ 957 debug("pledge: agent"); 958 if (pledge("stdio unix proc tty", NULL) == -1) 959 fatal_f("pledge(): %s", strerror(errno)); 960 } else { 961 debug("pledge: fork"); 962 if (pledge("stdio proc tty", NULL) == -1) 963 fatal_f("pledge(): %s", strerror(errno)); 964 } 965 /* XXX further things to do: 966 * 967 * - might be able to get rid of proc if we kill ~^Z 968 * - ssh -N (no session) 969 * - stdio forwarding 970 * - sessions without tty 971 */ 972 } 973 974 static void 975 process_cmdline(struct ssh *ssh) 976 { 977 void (*handler)(int); 978 char *s, *cmd; 979 int ok, delete = 0, local = 0, remote = 0, dynamic = 0; 980 struct Forward fwd; 981 982 memset(&fwd, 0, sizeof(fwd)); 983 984 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 985 handler = ssh_signal(SIGINT, SIG_IGN); 986 cmd = s = read_passphrase("\r\nssh> ", RP_ECHO); 987 if (s == NULL) 988 goto out; 989 while (isspace((u_char)*s)) 990 s++; 991 if (*s == '-') 992 s++; /* Skip cmdline '-', if any */ 993 if (*s == '\0') 994 goto out; 995 996 if (*s == 'h' || *s == 'H' || *s == '?') { 997 logit("Commands:"); 998 logit(" -L[bind_address:]port:host:hostport " 999 "Request local forward"); 1000 logit(" -R[bind_address:]port:host:hostport " 1001 "Request remote forward"); 1002 logit(" -D[bind_address:]port " 1003 "Request dynamic forward"); 1004 logit(" -KL[bind_address:]port " 1005 "Cancel local forward"); 1006 logit(" -KR[bind_address:]port " 1007 "Cancel remote forward"); 1008 logit(" -KD[bind_address:]port " 1009 "Cancel dynamic forward"); 1010 if (!options.permit_local_command) 1011 goto out; 1012 logit(" !args " 1013 "Execute local command"); 1014 goto out; 1015 } 1016 1017 if (*s == '!' && options.permit_local_command) { 1018 s++; 1019 ssh_local_cmd(s); 1020 goto out; 1021 } 1022 1023 if (*s == 'K') { 1024 delete = 1; 1025 s++; 1026 } 1027 if (*s == 'L') 1028 local = 1; 1029 else if (*s == 'R') 1030 remote = 1; 1031 else if (*s == 'D') 1032 dynamic = 1; 1033 else { 1034 logit("Invalid command."); 1035 goto out; 1036 } 1037 1038 while (isspace((u_char)*++s)) 1039 ; 1040 1041 /* XXX update list of forwards in options */ 1042 if (delete) { 1043 /* We pass 1 for dynamicfwd to restrict to 1 or 2 fields. */ 1044 if (!parse_forward(&fwd, s, 1, 0)) { 1045 logit("Bad forwarding close specification."); 1046 goto out; 1047 } 1048 if (remote) 1049 ok = channel_request_rforward_cancel(ssh, &fwd) == 0; 1050 else if (dynamic) 1051 ok = channel_cancel_lport_listener(ssh, &fwd, 1052 0, &options.fwd_opts) > 0; 1053 else 1054 ok = channel_cancel_lport_listener(ssh, &fwd, 1055 CHANNEL_CANCEL_PORT_STATIC, 1056 &options.fwd_opts) > 0; 1057 if (!ok) { 1058 logit("Unknown port forwarding."); 1059 goto out; 1060 } 1061 logit("Canceled forwarding."); 1062 } else { 1063 /* -R specs can be both dynamic or not, so check both. */ 1064 if (remote) { 1065 if (!parse_forward(&fwd, s, 0, remote) && 1066 !parse_forward(&fwd, s, 1, remote)) { 1067 logit("Bad remote forwarding specification."); 1068 goto out; 1069 } 1070 } else if (!parse_forward(&fwd, s, dynamic, remote)) { 1071 logit("Bad local forwarding specification."); 1072 goto out; 1073 } 1074 if (local || dynamic) { 1075 if (!channel_setup_local_fwd_listener(ssh, &fwd, 1076 &options.fwd_opts)) { 1077 logit("Port forwarding failed."); 1078 goto out; 1079 } 1080 } else { 1081 if (channel_request_remote_forwarding(ssh, &fwd) < 0) { 1082 logit("Port forwarding failed."); 1083 goto out; 1084 } 1085 } 1086 logit("Forwarding port."); 1087 } 1088 1089 out: 1090 ssh_signal(SIGINT, handler); 1091 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1092 free(cmd); 1093 free(fwd.listen_host); 1094 free(fwd.listen_path); 1095 free(fwd.connect_host); 1096 free(fwd.connect_path); 1097 } 1098 1099 /* reasons to suppress output of an escape command in help output */ 1100 #define SUPPRESS_NEVER 0 /* never suppress, always show */ 1101 #define SUPPRESS_MUXCLIENT 1 /* don't show in mux client sessions */ 1102 #define SUPPRESS_MUXMASTER 2 /* don't show in mux master sessions */ 1103 #define SUPPRESS_SYSLOG 4 /* don't show when logging to syslog */ 1104 #define SUPPRESS_NOCMDLINE 8 /* don't show when cmdline disabled*/ 1105 struct escape_help_text { 1106 const char *cmd; 1107 const char *text; 1108 unsigned int flags; 1109 }; 1110 static struct escape_help_text esc_txt[] = { 1111 {".", "terminate session", SUPPRESS_MUXMASTER}, 1112 {".", "terminate connection (and any multiplexed sessions)", 1113 SUPPRESS_MUXCLIENT}, 1114 {"B", "send a BREAK to the remote system", SUPPRESS_NEVER}, 1115 {"C", "open a command line", SUPPRESS_MUXCLIENT|SUPPRESS_NOCMDLINE}, 1116 {"R", "request rekey", SUPPRESS_NEVER}, 1117 {"V/v", "decrease/increase verbosity (LogLevel)", SUPPRESS_MUXCLIENT}, 1118 {"^Z", "suspend ssh", SUPPRESS_MUXCLIENT}, 1119 {"#", "list forwarded connections", SUPPRESS_NEVER}, 1120 {"&", "background ssh (when waiting for connections to terminate)", 1121 SUPPRESS_MUXCLIENT}, 1122 {"?", "this message", SUPPRESS_NEVER}, 1123 }; 1124 1125 static void 1126 print_escape_help(struct sshbuf *b, int escape_char, int mux_client, 1127 int using_stderr) 1128 { 1129 unsigned int i, suppress_flags; 1130 int r; 1131 1132 if ((r = sshbuf_putf(b, 1133 "%c?\r\nSupported escape sequences:\r\n", escape_char)) != 0) 1134 fatal_fr(r, "sshbuf_putf"); 1135 1136 suppress_flags = 1137 (mux_client ? SUPPRESS_MUXCLIENT : 0) | 1138 (mux_client ? 0 : SUPPRESS_MUXMASTER) | 1139 (using_stderr ? 0 : SUPPRESS_SYSLOG) | 1140 (options.enable_escape_commandline == 0 ? SUPPRESS_NOCMDLINE : 0); 1141 1142 for (i = 0; i < sizeof(esc_txt)/sizeof(esc_txt[0]); i++) { 1143 if (esc_txt[i].flags & suppress_flags) 1144 continue; 1145 if ((r = sshbuf_putf(b, " %c%-3s - %s\r\n", 1146 escape_char, esc_txt[i].cmd, esc_txt[i].text)) != 0) 1147 fatal_fr(r, "sshbuf_putf"); 1148 } 1149 1150 if ((r = sshbuf_putf(b, 1151 " %c%c - send the escape character by typing it twice\r\n" 1152 "(Note that escapes are only recognized immediately after " 1153 "newline.)\r\n", escape_char, escape_char)) != 0) 1154 fatal_fr(r, "sshbuf_putf"); 1155 } 1156 1157 /* 1158 * Process the characters one by one. 1159 */ 1160 static int 1161 process_escapes(struct ssh *ssh, Channel *c, 1162 struct sshbuf *bin, struct sshbuf *bout, struct sshbuf *berr, 1163 char *buf, int len) 1164 { 1165 pid_t pid; 1166 int r, bytes = 0; 1167 u_int i; 1168 u_char ch; 1169 char *s; 1170 struct escape_filter_ctx *efc; 1171 1172 if (c == NULL || c->filter_ctx == NULL || len <= 0) 1173 return 0; 1174 1175 efc = (struct escape_filter_ctx *)c->filter_ctx; 1176 1177 for (i = 0; i < (u_int)len; i++) { 1178 /* Get one character at a time. */ 1179 ch = buf[i]; 1180 1181 if (efc->escape_pending) { 1182 /* We have previously seen an escape character. */ 1183 /* Clear the flag now. */ 1184 efc->escape_pending = 0; 1185 1186 /* Process the escaped character. */ 1187 switch (ch) { 1188 case '.': 1189 /* Terminate the connection. */ 1190 if ((r = sshbuf_putf(berr, "%c.\r\n", 1191 efc->escape_char)) != 0) 1192 fatal_fr(r, "sshbuf_putf"); 1193 if (c && c->ctl_chan != -1) { 1194 channel_force_close(ssh, c, 1); 1195 return 0; 1196 } else 1197 quit_pending = 1; 1198 return -1; 1199 1200 case 'Z' - 64: 1201 /* XXX support this for mux clients */ 1202 if (c && c->ctl_chan != -1) { 1203 char b[16]; 1204 noescape: 1205 if (ch == 'Z' - 64) 1206 snprintf(b, sizeof b, "^Z"); 1207 else 1208 snprintf(b, sizeof b, "%c", ch); 1209 if ((r = sshbuf_putf(berr, 1210 "%c%s escape not available to " 1211 "multiplexed sessions\r\n", 1212 efc->escape_char, b)) != 0) 1213 fatal_fr(r, "sshbuf_putf"); 1214 continue; 1215 } 1216 /* Suspend the program. Inform the user */ 1217 if ((r = sshbuf_putf(berr, 1218 "%c^Z [suspend ssh]\r\n", 1219 efc->escape_char)) != 0) 1220 fatal_fr(r, "sshbuf_putf"); 1221 1222 /* Restore terminal modes and suspend. */ 1223 client_suspend_self(bin, bout, berr); 1224 1225 /* We have been continued. */ 1226 continue; 1227 1228 case 'B': 1229 if ((r = sshbuf_putf(berr, 1230 "%cB\r\n", efc->escape_char)) != 0) 1231 fatal_fr(r, "sshbuf_putf"); 1232 channel_request_start(ssh, c->self, "break", 0); 1233 if ((r = sshpkt_put_u32(ssh, 1000)) != 0 || 1234 (r = sshpkt_send(ssh)) != 0) 1235 fatal_fr(r, "send packet"); 1236 continue; 1237 1238 case 'R': 1239 if (ssh->compat & SSH_BUG_NOREKEY) 1240 logit("Server does not " 1241 "support re-keying"); 1242 else 1243 need_rekeying = 1; 1244 continue; 1245 1246 case 'V': 1247 /* FALLTHROUGH */ 1248 case 'v': 1249 if (c && c->ctl_chan != -1) 1250 goto noescape; 1251 if (!log_is_on_stderr()) { 1252 if ((r = sshbuf_putf(berr, 1253 "%c%c [Logging to syslog]\r\n", 1254 efc->escape_char, ch)) != 0) 1255 fatal_fr(r, "sshbuf_putf"); 1256 continue; 1257 } 1258 if (ch == 'V' && options.log_level > 1259 SYSLOG_LEVEL_QUIET) 1260 log_change_level(--options.log_level); 1261 if (ch == 'v' && options.log_level < 1262 SYSLOG_LEVEL_DEBUG3) 1263 log_change_level(++options.log_level); 1264 if ((r = sshbuf_putf(berr, 1265 "%c%c [LogLevel %s]\r\n", 1266 efc->escape_char, ch, 1267 log_level_name(options.log_level))) != 0) 1268 fatal_fr(r, "sshbuf_putf"); 1269 continue; 1270 1271 case '&': 1272 if (c->ctl_chan != -1) 1273 goto noescape; 1274 /* 1275 * Detach the program (continue to serve 1276 * connections, but put in background and no 1277 * more new connections). 1278 */ 1279 /* Restore tty modes. */ 1280 leave_raw_mode( 1281 options.request_tty == REQUEST_TTY_FORCE); 1282 1283 /* Stop listening for new connections. */ 1284 channel_stop_listening(ssh); 1285 1286 if ((r = sshbuf_putf(berr, "%c& " 1287 "[backgrounded]\n", efc->escape_char)) != 0) 1288 fatal_fr(r, "sshbuf_putf"); 1289 1290 /* Fork into background. */ 1291 pid = fork(); 1292 if (pid == -1) { 1293 error("fork: %.100s", strerror(errno)); 1294 continue; 1295 } 1296 if (pid != 0) { /* This is the parent. */ 1297 /* The parent just exits. */ 1298 exit(0); 1299 } 1300 /* The child continues serving connections. */ 1301 /* fake EOF on stdin */ 1302 if ((r = sshbuf_put_u8(bin, 4)) != 0) 1303 fatal_fr(r, "sshbuf_put_u8"); 1304 return -1; 1305 case '?': 1306 print_escape_help(berr, efc->escape_char, 1307 (c && c->ctl_chan != -1), 1308 log_is_on_stderr()); 1309 continue; 1310 1311 case '#': 1312 if ((r = sshbuf_putf(berr, "%c#\r\n", 1313 efc->escape_char)) != 0) 1314 fatal_fr(r, "sshbuf_putf"); 1315 s = channel_open_message(ssh); 1316 if ((r = sshbuf_put(berr, s, strlen(s))) != 0) 1317 fatal_fr(r, "sshbuf_put"); 1318 free(s); 1319 continue; 1320 1321 case 'C': 1322 if (c && c->ctl_chan != -1) 1323 goto noescape; 1324 if (options.enable_escape_commandline == 0) { 1325 if ((r = sshbuf_putf(berr, 1326 "commandline disabled\r\n")) != 0) 1327 fatal_fr(r, "sshbuf_putf"); 1328 continue; 1329 } 1330 process_cmdline(ssh); 1331 continue; 1332 1333 default: 1334 if (ch != efc->escape_char) { 1335 if ((r = sshbuf_put_u8(bin, 1336 efc->escape_char)) != 0) 1337 fatal_fr(r, "sshbuf_put_u8"); 1338 bytes++; 1339 } 1340 /* Escaped characters fall through here */ 1341 break; 1342 } 1343 } else { 1344 /* 1345 * The previous character was not an escape char. 1346 * Check if this is an escape. 1347 */ 1348 if (last_was_cr && ch == efc->escape_char) { 1349 /* 1350 * It is. Set the flag and continue to 1351 * next character. 1352 */ 1353 efc->escape_pending = 1; 1354 continue; 1355 } 1356 } 1357 1358 /* 1359 * Normal character. Record whether it was a newline, 1360 * and append it to the buffer. 1361 */ 1362 last_was_cr = (ch == '\r' || ch == '\n'); 1363 if ((r = sshbuf_put_u8(bin, ch)) != 0) 1364 fatal_fr(r, "sshbuf_put_u8"); 1365 bytes++; 1366 } 1367 return bytes; 1368 } 1369 1370 /* 1371 * Get packets from the connection input buffer, and process them as long as 1372 * there are packets available. 1373 * 1374 * Any unknown packets received during the actual 1375 * session cause the session to terminate. This is 1376 * intended to make debugging easier since no 1377 * confirmations are sent. Any compatible protocol 1378 * extensions must be negotiated during the 1379 * preparatory phase. 1380 */ 1381 1382 static void 1383 client_process_buffered_input_packets(struct ssh *ssh) 1384 { 1385 ssh_dispatch_run_fatal(ssh, DISPATCH_NONBLOCK, &quit_pending); 1386 } 1387 1388 /* scan buf[] for '~' before sending data to the peer */ 1389 1390 /* Helper: allocate a new escape_filter_ctx and fill in its escape char */ 1391 void * 1392 client_new_escape_filter_ctx(int escape_char) 1393 { 1394 struct escape_filter_ctx *ret; 1395 1396 ret = xcalloc(1, sizeof(*ret)); 1397 ret->escape_pending = 0; 1398 ret->escape_char = escape_char; 1399 return (void *)ret; 1400 } 1401 1402 /* Free the escape filter context on channel free */ 1403 void 1404 client_filter_cleanup(struct ssh *ssh, int cid, void *ctx) 1405 { 1406 free(ctx); 1407 } 1408 1409 int 1410 client_simple_escape_filter(struct ssh *ssh, Channel *c, char *buf, int len) 1411 { 1412 if (c->extended_usage != CHAN_EXTENDED_WRITE) 1413 return 0; 1414 1415 return process_escapes(ssh, c, c->input, c->output, c->extended, 1416 buf, len); 1417 } 1418 1419 static void 1420 client_channel_closed(struct ssh *ssh, int id, int force, void *arg) 1421 { 1422 channel_cancel_cleanup(ssh, id); 1423 session_closed = 1; 1424 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1425 } 1426 1427 /* 1428 * Implements the interactive session with the server. This is called after 1429 * the user has been authenticated, and a command has been started on the 1430 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character 1431 * used as an escape character for terminating or suspending the session. 1432 */ 1433 int 1434 client_loop(struct ssh *ssh, int have_pty, int escape_char_arg, 1435 int ssh2_chan_id) 1436 { 1437 struct pollfd *pfd = NULL; 1438 u_int npfd_alloc = 0, npfd_active = 0; 1439 double start_time, total_time; 1440 int channel_did_enqueue = 0, r; 1441 u_int64_t ibytes, obytes; 1442 int conn_in_ready, conn_out_ready; 1443 sigset_t bsigset, osigset; 1444 1445 debug("Entering interactive session."); 1446 session_ident = ssh2_chan_id; 1447 1448 if (options.control_master && 1449 !option_clear_or_none(options.control_path)) { 1450 debug("pledge: id"); 1451 if (pledge("stdio rpath wpath cpath unix inet dns recvfd sendfd proc exec id tty", 1452 NULL) == -1) 1453 fatal_f("pledge(): %s", strerror(errno)); 1454 1455 } else if (options.forward_x11 || options.permit_local_command) { 1456 debug("pledge: exec"); 1457 if (pledge("stdio rpath wpath cpath unix inet dns proc exec tty", 1458 NULL) == -1) 1459 fatal_f("pledge(): %s", strerror(errno)); 1460 1461 } else if (options.update_hostkeys) { 1462 debug("pledge: filesystem"); 1463 if (pledge("stdio rpath wpath cpath unix inet dns proc tty", 1464 NULL) == -1) 1465 fatal_f("pledge(): %s", strerror(errno)); 1466 1467 } else if (!option_clear_or_none(options.proxy_command) || 1468 options.fork_after_authentication) { 1469 debug("pledge: proc"); 1470 if (pledge("stdio cpath unix inet dns proc tty", NULL) == -1) 1471 fatal_f("pledge(): %s", strerror(errno)); 1472 1473 } else { 1474 debug("pledge: network"); 1475 if (pledge("stdio unix inet dns proc tty", NULL) == -1) 1476 fatal_f("pledge(): %s", strerror(errno)); 1477 } 1478 1479 /* might be able to tighten now */ 1480 client_repledge(); 1481 1482 start_time = monotime_double(); 1483 1484 /* Initialize variables. */ 1485 last_was_cr = 1; 1486 exit_status = -1; 1487 connection_in = ssh_packet_get_connection_in(ssh); 1488 connection_out = ssh_packet_get_connection_out(ssh); 1489 1490 quit_pending = 0; 1491 1492 client_init_dispatch(ssh); 1493 1494 /* 1495 * Set signal handlers, (e.g. to restore non-blocking mode) 1496 * but don't overwrite SIG_IGN, matches behaviour from rsh(1) 1497 */ 1498 if (ssh_signal(SIGHUP, SIG_IGN) != SIG_IGN) 1499 ssh_signal(SIGHUP, signal_handler); 1500 if (ssh_signal(SIGINT, SIG_IGN) != SIG_IGN) 1501 ssh_signal(SIGINT, signal_handler); 1502 if (ssh_signal(SIGQUIT, SIG_IGN) != SIG_IGN) 1503 ssh_signal(SIGQUIT, signal_handler); 1504 if (ssh_signal(SIGTERM, SIG_IGN) != SIG_IGN) 1505 ssh_signal(SIGTERM, signal_handler); 1506 ssh_signal(SIGWINCH, window_change_handler); 1507 1508 if (have_pty) 1509 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1510 1511 if (session_ident != -1) { 1512 if (escape_char_arg != SSH_ESCAPECHAR_NONE) { 1513 channel_register_filter(ssh, session_ident, 1514 client_simple_escape_filter, NULL, 1515 client_filter_cleanup, 1516 client_new_escape_filter_ctx( 1517 escape_char_arg)); 1518 } 1519 channel_register_cleanup(ssh, session_ident, 1520 client_channel_closed, 0); 1521 } 1522 1523 schedule_server_alive_check(); 1524 1525 if (sigemptyset(&bsigset) == -1 || 1526 sigaddset(&bsigset, SIGHUP) == -1 || 1527 sigaddset(&bsigset, SIGINT) == -1 || 1528 sigaddset(&bsigset, SIGQUIT) == -1 || 1529 sigaddset(&bsigset, SIGTERM) == -1) 1530 error_f("bsigset setup: %s", strerror(errno)); 1531 1532 /* Main loop of the client for the interactive session mode. */ 1533 while (!quit_pending) { 1534 channel_did_enqueue = 0; 1535 1536 /* Process buffered packets sent by the server. */ 1537 client_process_buffered_input_packets(ssh); 1538 1539 if (session_closed && !channel_still_open(ssh)) 1540 break; 1541 1542 if (ssh_packet_is_rekeying(ssh)) { 1543 debug("rekeying in progress"); 1544 } else if (need_rekeying) { 1545 /* manual rekey request */ 1546 debug("need rekeying"); 1547 if ((r = kex_start_rekex(ssh)) != 0) 1548 fatal_fr(r, "kex_start_rekex"); 1549 need_rekeying = 0; 1550 } else { 1551 /* 1552 * Make packets from buffered channel data, and 1553 * enqueue them for sending to the server. 1554 */ 1555 if (ssh_packet_not_very_much_data_to_write(ssh)) 1556 channel_did_enqueue = channel_output_poll(ssh); 1557 1558 /* 1559 * Check if the window size has changed, and buffer a 1560 * message about it to the server if so. 1561 */ 1562 client_check_window_change(ssh); 1563 } 1564 /* 1565 * Wait until we have something to do (something becomes 1566 * available on one of the descriptors). 1567 */ 1568 if (sigprocmask(SIG_BLOCK, &bsigset, &osigset) == -1) 1569 error_f("bsigset sigprocmask: %s", strerror(errno)); 1570 if (quit_pending) 1571 break; 1572 client_wait_until_can_do_something(ssh, &pfd, &npfd_alloc, 1573 &npfd_active, channel_did_enqueue, &osigset, 1574 &conn_in_ready, &conn_out_ready); 1575 if (sigprocmask(SIG_SETMASK, &osigset, NULL) == -1) 1576 error_f("osigset sigprocmask: %s", strerror(errno)); 1577 1578 if (quit_pending) 1579 break; 1580 1581 /* Do channel operations. */ 1582 channel_after_poll(ssh, pfd, npfd_active); 1583 1584 /* Buffer input from the connection. */ 1585 if (conn_in_ready) 1586 client_process_net_input(ssh); 1587 1588 if (quit_pending) 1589 break; 1590 1591 /* A timeout may have triggered rekeying */ 1592 if ((r = ssh_packet_check_rekey(ssh)) != 0) 1593 fatal_fr(r, "cannot start rekeying"); 1594 1595 /* 1596 * Send as much buffered packet data as possible to the 1597 * sender. 1598 */ 1599 if (conn_out_ready) { 1600 if ((r = ssh_packet_write_poll(ssh)) != 0) { 1601 sshpkt_fatal(ssh, r, 1602 "%s: ssh_packet_write_poll", __func__); 1603 } 1604 } 1605 1606 /* 1607 * If we are a backgrounded control master, and the 1608 * timeout has expired without any active client 1609 * connections, then quit. 1610 */ 1611 if (control_persist_exit_time > 0) { 1612 if (monotime() >= control_persist_exit_time) { 1613 debug("ControlPersist timeout expired"); 1614 break; 1615 } 1616 } 1617 } 1618 free(pfd); 1619 1620 /* Terminate the session. */ 1621 1622 /* 1623 * In interactive mode (with pseudo tty) display a message indicating 1624 * that the connection has been closed. 1625 */ 1626 if (have_pty && options.log_level >= SYSLOG_LEVEL_INFO) 1627 quit_message("Connection to %s closed.", host); 1628 1629 1630 /* Stop watching for window change. */ 1631 ssh_signal(SIGWINCH, SIG_DFL); 1632 1633 if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 || 1634 (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_BY_APPLICATION)) != 0 || 1635 (r = sshpkt_put_cstring(ssh, "disconnected by user")) != 0 || 1636 (r = sshpkt_put_cstring(ssh, "")) != 0 || /* language tag */ 1637 (r = sshpkt_send(ssh)) != 0 || 1638 (r = ssh_packet_write_wait(ssh)) != 0) 1639 fatal_fr(r, "send disconnect"); 1640 1641 channel_free_all(ssh); 1642 1643 if (have_pty) 1644 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1645 1646 /* 1647 * If there was no shell or command requested, there will be no remote 1648 * exit status to be returned. In that case, clear error code if the 1649 * connection was deliberately terminated at this end. 1650 */ 1651 if (options.session_type == SESSION_TYPE_NONE && 1652 received_signal == SIGTERM) { 1653 received_signal = 0; 1654 exit_status = 0; 1655 } 1656 1657 if (received_signal) { 1658 verbose("Killed by signal %d.", (int) received_signal); 1659 cleanup_exit(255); 1660 } 1661 1662 /* Report bytes transferred, and transfer rates. */ 1663 total_time = monotime_double() - start_time; 1664 ssh_packet_get_bytes(ssh, &ibytes, &obytes); 1665 verbose("Transferred: sent %llu, received %llu bytes, in %.1f seconds", 1666 (unsigned long long)obytes, (unsigned long long)ibytes, total_time); 1667 if (total_time > 0) 1668 verbose("Bytes per second: sent %.1f, received %.1f", 1669 obytes / total_time, ibytes / total_time); 1670 /* Return the exit status of the program. */ 1671 debug("Exit status %d", exit_status); 1672 return exit_status; 1673 } 1674 1675 /*********/ 1676 1677 static Channel * 1678 client_request_forwarded_tcpip(struct ssh *ssh, const char *request_type, 1679 int rchan, u_int rwindow, u_int rmaxpack) 1680 { 1681 Channel *c = NULL; 1682 struct sshbuf *b = NULL; 1683 char *listen_address, *originator_address; 1684 u_int listen_port, originator_port; 1685 int r; 1686 1687 /* Get rest of the packet */ 1688 if ((r = sshpkt_get_cstring(ssh, &listen_address, NULL)) != 0 || 1689 (r = sshpkt_get_u32(ssh, &listen_port)) != 0 || 1690 (r = sshpkt_get_cstring(ssh, &originator_address, NULL)) != 0 || 1691 (r = sshpkt_get_u32(ssh, &originator_port)) != 0 || 1692 (r = sshpkt_get_end(ssh)) != 0) 1693 fatal_fr(r, "parse packet"); 1694 1695 debug_f("listen %s port %d, originator %s port %d", 1696 listen_address, listen_port, originator_address, originator_port); 1697 1698 if (listen_port > 0xffff) 1699 error_f("invalid listen port"); 1700 else if (originator_port > 0xffff) 1701 error_f("invalid originator port"); 1702 else { 1703 c = channel_connect_by_listen_address(ssh, 1704 listen_address, listen_port, "forwarded-tcpip", 1705 originator_address); 1706 } 1707 1708 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) { 1709 if ((b = sshbuf_new()) == NULL) { 1710 error_f("alloc reply"); 1711 goto out; 1712 } 1713 /* reconstruct and send to muxclient */ 1714 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 1715 (r = sshbuf_put_u8(b, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1716 (r = sshbuf_put_cstring(b, request_type)) != 0 || 1717 (r = sshbuf_put_u32(b, rchan)) != 0 || 1718 (r = sshbuf_put_u32(b, rwindow)) != 0 || 1719 (r = sshbuf_put_u32(b, rmaxpack)) != 0 || 1720 (r = sshbuf_put_cstring(b, listen_address)) != 0 || 1721 (r = sshbuf_put_u32(b, listen_port)) != 0 || 1722 (r = sshbuf_put_cstring(b, originator_address)) != 0 || 1723 (r = sshbuf_put_u32(b, originator_port)) != 0 || 1724 (r = sshbuf_put_stringb(c->output, b)) != 0) { 1725 error_fr(r, "compose for muxclient"); 1726 goto out; 1727 } 1728 } 1729 1730 out: 1731 sshbuf_free(b); 1732 free(originator_address); 1733 free(listen_address); 1734 return c; 1735 } 1736 1737 static Channel * 1738 client_request_forwarded_streamlocal(struct ssh *ssh, 1739 const char *request_type, int rchan) 1740 { 1741 Channel *c = NULL; 1742 char *listen_path; 1743 int r; 1744 1745 /* Get the remote path. */ 1746 if ((r = sshpkt_get_cstring(ssh, &listen_path, NULL)) != 0 || 1747 (r = sshpkt_get_string(ssh, NULL, NULL)) != 0 || /* reserved */ 1748 (r = sshpkt_get_end(ssh)) != 0) 1749 fatal_fr(r, "parse packet"); 1750 1751 debug_f("request: %s", listen_path); 1752 1753 c = channel_connect_by_listen_path(ssh, listen_path, 1754 "forwarded-streamlocal@openssh.com", "forwarded-streamlocal"); 1755 free(listen_path); 1756 return c; 1757 } 1758 1759 static Channel * 1760 client_request_x11(struct ssh *ssh, const char *request_type, int rchan) 1761 { 1762 Channel *c = NULL; 1763 char *originator; 1764 u_int originator_port; 1765 int r, sock; 1766 1767 if (!options.forward_x11) { 1768 error("Warning: ssh server tried X11 forwarding."); 1769 error("Warning: this is probably a break-in attempt by a " 1770 "malicious server."); 1771 return NULL; 1772 } 1773 if (x11_refuse_time != 0 && monotime() >= x11_refuse_time) { 1774 verbose("Rejected X11 connection after ForwardX11Timeout " 1775 "expired"); 1776 return NULL; 1777 } 1778 if ((r = sshpkt_get_cstring(ssh, &originator, NULL)) != 0 || 1779 (r = sshpkt_get_u32(ssh, &originator_port)) != 0 || 1780 (r = sshpkt_get_end(ssh)) != 0) 1781 fatal_fr(r, "parse packet"); 1782 /* XXX check permission */ 1783 /* XXX range check originator port? */ 1784 debug("client_request_x11: request from %s %u", originator, 1785 originator_port); 1786 free(originator); 1787 sock = x11_connect_display(ssh); 1788 if (sock < 0) 1789 return NULL; 1790 c = channel_new(ssh, "x11-connection", 1791 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1792 CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); 1793 c->force_drain = 1; 1794 return c; 1795 } 1796 1797 static Channel * 1798 client_request_agent(struct ssh *ssh, const char *request_type, int rchan) 1799 { 1800 Channel *c = NULL; 1801 int r, sock; 1802 1803 if (!options.forward_agent) { 1804 error("Warning: ssh server tried agent forwarding."); 1805 error("Warning: this is probably a break-in attempt by a " 1806 "malicious server."); 1807 return NULL; 1808 } 1809 if (forward_agent_sock_path == NULL) { 1810 r = ssh_get_authentication_socket(&sock); 1811 } else { 1812 r = ssh_get_authentication_socket_path(forward_agent_sock_path, &sock); 1813 } 1814 if (r != 0) { 1815 if (r != SSH_ERR_AGENT_NOT_PRESENT) 1816 debug_fr(r, "ssh_get_authentication_socket"); 1817 return NULL; 1818 } 1819 if ((r = ssh_agent_bind_hostkey(sock, ssh->kex->initial_hostkey, 1820 ssh->kex->session_id, ssh->kex->initial_sig, 1)) == 0) 1821 debug_f("bound agent to hostkey"); 1822 else 1823 debug2_fr(r, "ssh_agent_bind_hostkey"); 1824 1825 c = channel_new(ssh, "agent-connection", 1826 SSH_CHANNEL_OPEN, sock, sock, -1, 1827 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, 1828 "authentication agent connection", 1); 1829 c->force_drain = 1; 1830 return c; 1831 } 1832 1833 char * 1834 client_request_tun_fwd(struct ssh *ssh, int tun_mode, 1835 int local_tun, int remote_tun, channel_open_fn *cb, void *cbctx) 1836 { 1837 Channel *c; 1838 int r, fd; 1839 char *ifname = NULL; 1840 1841 if (tun_mode == SSH_TUNMODE_NO) 1842 return 0; 1843 1844 debug("Requesting tun unit %d in mode %d", local_tun, tun_mode); 1845 1846 /* Open local tunnel device */ 1847 if ((fd = tun_open(local_tun, tun_mode, &ifname)) == -1) { 1848 error("Tunnel device open failed."); 1849 return NULL; 1850 } 1851 debug("Tunnel forwarding using interface %s", ifname); 1852 1853 c = channel_new(ssh, "tun-connection", SSH_CHANNEL_OPENING, fd, fd, -1, 1854 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1); 1855 c->datagram = 1; 1856 1857 if (cb != NULL) 1858 channel_register_open_confirm(ssh, c->self, cb, cbctx); 1859 1860 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1861 (r = sshpkt_put_cstring(ssh, "tun@openssh.com")) != 0 || 1862 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1863 (r = sshpkt_put_u32(ssh, c->local_window_max)) != 0 || 1864 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 1865 (r = sshpkt_put_u32(ssh, tun_mode)) != 0 || 1866 (r = sshpkt_put_u32(ssh, remote_tun)) != 0 || 1867 (r = sshpkt_send(ssh)) != 0) 1868 sshpkt_fatal(ssh, r, "%s: send reply", __func__); 1869 1870 return ifname; 1871 } 1872 1873 /* XXXX move to generic input handler */ 1874 static int 1875 client_input_channel_open(int type, u_int32_t seq, struct ssh *ssh) 1876 { 1877 Channel *c = NULL; 1878 char *ctype = NULL; 1879 int r; 1880 u_int rchan; 1881 size_t len; 1882 u_int rmaxpack, rwindow; 1883 1884 if ((r = sshpkt_get_cstring(ssh, &ctype, &len)) != 0 || 1885 (r = sshpkt_get_u32(ssh, &rchan)) != 0 || 1886 (r = sshpkt_get_u32(ssh, &rwindow)) != 0 || 1887 (r = sshpkt_get_u32(ssh, &rmaxpack)) != 0) 1888 goto out; 1889 1890 debug("client_input_channel_open: ctype %s rchan %d win %d max %d", 1891 ctype, rchan, rwindow, rmaxpack); 1892 1893 if (strcmp(ctype, "forwarded-tcpip") == 0) { 1894 c = client_request_forwarded_tcpip(ssh, ctype, rchan, rwindow, 1895 rmaxpack); 1896 } else if (strcmp(ctype, "forwarded-streamlocal@openssh.com") == 0) { 1897 c = client_request_forwarded_streamlocal(ssh, ctype, rchan); 1898 } else if (strcmp(ctype, "x11") == 0) { 1899 c = client_request_x11(ssh, ctype, rchan); 1900 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) { 1901 c = client_request_agent(ssh, ctype, rchan); 1902 } 1903 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) { 1904 debug3("proxied to downstream: %s", ctype); 1905 } else if (c != NULL) { 1906 debug("confirm %s", ctype); 1907 c->remote_id = rchan; 1908 c->have_remote_id = 1; 1909 c->remote_window = rwindow; 1910 c->remote_maxpacket = rmaxpack; 1911 if (c->type != SSH_CHANNEL_CONNECTING) { 1912 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 1913 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1914 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1915 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1916 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 1917 (r = sshpkt_send(ssh)) != 0) 1918 sshpkt_fatal(ssh, r, "%s: send reply", __func__); 1919 } 1920 } else { 1921 debug("failure %s", ctype); 1922 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || 1923 (r = sshpkt_put_u32(ssh, rchan)) != 0 || 1924 (r = sshpkt_put_u32(ssh, SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED)) != 0 || 1925 (r = sshpkt_put_cstring(ssh, "open failed")) != 0 || 1926 (r = sshpkt_put_cstring(ssh, "")) != 0 || 1927 (r = sshpkt_send(ssh)) != 0) 1928 sshpkt_fatal(ssh, r, "%s: send failure", __func__); 1929 } 1930 r = 0; 1931 out: 1932 free(ctype); 1933 return r; 1934 } 1935 1936 static int 1937 client_input_channel_req(int type, u_int32_t seq, struct ssh *ssh) 1938 { 1939 Channel *c = NULL; 1940 char *rtype = NULL; 1941 u_char reply; 1942 u_int id, exitval; 1943 int r, success = 0; 1944 1945 if ((r = sshpkt_get_u32(ssh, &id)) != 0) 1946 return r; 1947 if (id <= INT_MAX) 1948 c = channel_lookup(ssh, id); 1949 if (channel_proxy_upstream(c, type, seq, ssh)) 1950 return 0; 1951 if ((r = sshpkt_get_cstring(ssh, &rtype, NULL)) != 0 || 1952 (r = sshpkt_get_u8(ssh, &reply)) != 0) 1953 goto out; 1954 1955 debug("client_input_channel_req: channel %u rtype %s reply %d", 1956 id, rtype, reply); 1957 1958 if (c == NULL) { 1959 error("client_input_channel_req: channel %d: " 1960 "unknown channel", id); 1961 } else if (strcmp(rtype, "eow@openssh.com") == 0) { 1962 if ((r = sshpkt_get_end(ssh)) != 0) 1963 goto out; 1964 chan_rcvd_eow(ssh, c); 1965 } else if (strcmp(rtype, "exit-status") == 0) { 1966 if ((r = sshpkt_get_u32(ssh, &exitval)) != 0) 1967 goto out; 1968 if (c->ctl_chan != -1) { 1969 mux_exit_message(ssh, c, exitval); 1970 success = 1; 1971 } else if ((int)id == session_ident) { 1972 /* Record exit value of local session */ 1973 success = 1; 1974 exit_status = exitval; 1975 } else { 1976 /* Probably for a mux channel that has already closed */ 1977 debug_f("no sink for exit-status on channel %d", 1978 id); 1979 } 1980 if ((r = sshpkt_get_end(ssh)) != 0) 1981 goto out; 1982 } 1983 if (reply && c != NULL && !(c->flags & CHAN_CLOSE_SENT)) { 1984 if (!c->have_remote_id) 1985 fatal_f("channel %d: no remote_id", c->self); 1986 if ((r = sshpkt_start(ssh, success ? 1987 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE)) != 0 || 1988 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1989 (r = sshpkt_send(ssh)) != 0) 1990 sshpkt_fatal(ssh, r, "%s: send failure", __func__); 1991 } 1992 r = 0; 1993 out: 1994 free(rtype); 1995 return r; 1996 } 1997 1998 struct hostkeys_update_ctx { 1999 /* The hostname and (optionally) IP address string for the server */ 2000 char *host_str, *ip_str; 2001 2002 /* 2003 * Keys received from the server and a flag for each indicating 2004 * whether they already exist in known_hosts. 2005 * keys_match is filled in by hostkeys_find() and later (for new 2006 * keys) by client_global_hostkeys_prove_confirm(). 2007 */ 2008 struct sshkey **keys; 2009 u_int *keys_match; /* mask of HKF_MATCH_* from hostfile.h */ 2010 int *keys_verified; /* flag for new keys verified by server */ 2011 size_t nkeys, nnew, nincomplete; /* total, new keys, incomplete match */ 2012 2013 /* 2014 * Keys that are in known_hosts, but were not present in the update 2015 * from the server (i.e. scheduled to be deleted). 2016 * Filled in by hostkeys_find(). 2017 */ 2018 struct sshkey **old_keys; 2019 size_t nold; 2020 2021 /* Various special cases. */ 2022 int complex_hostspec; /* wildcard or manual pattern-list host name */ 2023 int ca_available; /* saw CA key for this host */ 2024 int old_key_seen; /* saw old key with other name/addr */ 2025 int other_name_seen; /* saw key with other name/addr */ 2026 }; 2027 2028 static void 2029 hostkeys_update_ctx_free(struct hostkeys_update_ctx *ctx) 2030 { 2031 size_t i; 2032 2033 if (ctx == NULL) 2034 return; 2035 for (i = 0; i < ctx->nkeys; i++) 2036 sshkey_free(ctx->keys[i]); 2037 free(ctx->keys); 2038 free(ctx->keys_match); 2039 free(ctx->keys_verified); 2040 for (i = 0; i < ctx->nold; i++) 2041 sshkey_free(ctx->old_keys[i]); 2042 free(ctx->old_keys); 2043 free(ctx->host_str); 2044 free(ctx->ip_str); 2045 free(ctx); 2046 } 2047 2048 /* 2049 * Returns non-zero if a known_hosts hostname list is not of a form that 2050 * can be handled by UpdateHostkeys. These include wildcard hostnames and 2051 * hostnames lists that do not follow the form host[,ip]. 2052 */ 2053 static int 2054 hostspec_is_complex(const char *hosts) 2055 { 2056 char *cp; 2057 2058 /* wildcard */ 2059 if (strchr(hosts, '*') != NULL || strchr(hosts, '?') != NULL) 2060 return 1; 2061 /* single host/ip = ok */ 2062 if ((cp = strchr(hosts, ',')) == NULL) 2063 return 0; 2064 /* more than two entries on the line */ 2065 if (strchr(cp + 1, ',') != NULL) 2066 return 1; 2067 /* XXX maybe parse cp+1 and ensure it is an IP? */ 2068 return 0; 2069 } 2070 2071 /* callback to search for ctx->keys in known_hosts */ 2072 static int 2073 hostkeys_find(struct hostkey_foreach_line *l, void *_ctx) 2074 { 2075 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 2076 size_t i; 2077 struct sshkey **tmp; 2078 2079 if (l->key == NULL) 2080 return 0; 2081 if (l->status != HKF_STATUS_MATCHED) { 2082 /* Record if one of the keys appears on a non-matching line */ 2083 for (i = 0; i < ctx->nkeys; i++) { 2084 if (sshkey_equal(l->key, ctx->keys[i])) { 2085 ctx->other_name_seen = 1; 2086 debug3_f("found %s key under different " 2087 "name/addr at %s:%ld", 2088 sshkey_ssh_name(ctx->keys[i]), 2089 l->path, l->linenum); 2090 return 0; 2091 } 2092 } 2093 return 0; 2094 } 2095 /* Don't proceed if revocation or CA markers are present */ 2096 /* XXX relax this */ 2097 if (l->marker != MRK_NONE) { 2098 debug3_f("hostkeys file %s:%ld has CA/revocation marker", 2099 l->path, l->linenum); 2100 ctx->complex_hostspec = 1; 2101 return 0; 2102 } 2103 2104 /* If CheckHostIP is enabled, then check for mismatched hostname/addr */ 2105 if (ctx->ip_str != NULL && strchr(l->hosts, ',') != NULL) { 2106 if ((l->match & HKF_MATCH_HOST) == 0) { 2107 /* Record if address matched a different hostname. */ 2108 ctx->other_name_seen = 1; 2109 debug3_f("found address %s against different hostname " 2110 "at %s:%ld", ctx->ip_str, l->path, l->linenum); 2111 return 0; 2112 } else if ((l->match & HKF_MATCH_IP) == 0) { 2113 /* Record if hostname matched a different address. */ 2114 ctx->other_name_seen = 1; 2115 debug3_f("found hostname %s against different address " 2116 "at %s:%ld", ctx->host_str, l->path, l->linenum); 2117 } 2118 } 2119 2120 /* 2121 * UpdateHostkeys is skipped for wildcard host names and hostnames 2122 * that contain more than two entries (ssh never writes these). 2123 */ 2124 if (hostspec_is_complex(l->hosts)) { 2125 debug3_f("hostkeys file %s:%ld complex host specification", 2126 l->path, l->linenum); 2127 ctx->complex_hostspec = 1; 2128 return 0; 2129 } 2130 2131 /* Mark off keys we've already seen for this host */ 2132 for (i = 0; i < ctx->nkeys; i++) { 2133 if (!sshkey_equal(l->key, ctx->keys[i])) 2134 continue; 2135 debug3_f("found %s key at %s:%ld", 2136 sshkey_ssh_name(ctx->keys[i]), l->path, l->linenum); 2137 ctx->keys_match[i] |= l->match; 2138 return 0; 2139 } 2140 /* This line contained a key that not offered by the server */ 2141 debug3_f("deprecated %s key at %s:%ld", sshkey_ssh_name(l->key), 2142 l->path, l->linenum); 2143 if ((tmp = recallocarray(ctx->old_keys, ctx->nold, ctx->nold + 1, 2144 sizeof(*ctx->old_keys))) == NULL) 2145 fatal_f("recallocarray failed nold = %zu", ctx->nold); 2146 ctx->old_keys = tmp; 2147 ctx->old_keys[ctx->nold++] = l->key; 2148 l->key = NULL; 2149 2150 return 0; 2151 } 2152 2153 /* callback to search for ctx->old_keys in known_hosts under other names */ 2154 static int 2155 hostkeys_check_old(struct hostkey_foreach_line *l, void *_ctx) 2156 { 2157 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 2158 size_t i; 2159 int hashed; 2160 2161 /* only care about lines that *don't* match the active host spec */ 2162 if (l->status == HKF_STATUS_MATCHED || l->key == NULL) 2163 return 0; 2164 2165 hashed = l->match & (HKF_MATCH_HOST_HASHED|HKF_MATCH_IP_HASHED); 2166 for (i = 0; i < ctx->nold; i++) { 2167 if (!sshkey_equal(l->key, ctx->old_keys[i])) 2168 continue; 2169 debug3_f("found deprecated %s key at %s:%ld as %s", 2170 sshkey_ssh_name(ctx->old_keys[i]), l->path, l->linenum, 2171 hashed ? "[HASHED]" : l->hosts); 2172 ctx->old_key_seen = 1; 2173 break; 2174 } 2175 return 0; 2176 } 2177 2178 /* 2179 * Check known_hosts files for deprecated keys under other names. Returns 0 2180 * on success or -1 on failure. Updates ctx->old_key_seen if deprecated keys 2181 * exist under names other than the active hostname/IP. 2182 */ 2183 static int 2184 check_old_keys_othernames(struct hostkeys_update_ctx *ctx) 2185 { 2186 size_t i; 2187 int r; 2188 2189 debug2_f("checking for %zu deprecated keys", ctx->nold); 2190 for (i = 0; i < options.num_user_hostfiles; i++) { 2191 debug3_f("searching %s for %s / %s", 2192 options.user_hostfiles[i], ctx->host_str, 2193 ctx->ip_str ? ctx->ip_str : "(none)"); 2194 if ((r = hostkeys_foreach(options.user_hostfiles[i], 2195 hostkeys_check_old, ctx, ctx->host_str, ctx->ip_str, 2196 HKF_WANT_PARSE_KEY, 0)) != 0) { 2197 if (r == SSH_ERR_SYSTEM_ERROR && errno == ENOENT) { 2198 debug_f("hostkeys file %s does not exist", 2199 options.user_hostfiles[i]); 2200 continue; 2201 } 2202 error_fr(r, "hostkeys_foreach failed for %s", 2203 options.user_hostfiles[i]); 2204 return -1; 2205 } 2206 } 2207 return 0; 2208 } 2209 2210 static void 2211 hostkey_change_preamble(LogLevel loglevel) 2212 { 2213 do_log2(loglevel, "The server has updated its host keys."); 2214 do_log2(loglevel, "These changes were verified by the server's " 2215 "existing trusted key."); 2216 } 2217 2218 static void 2219 update_known_hosts(struct hostkeys_update_ctx *ctx) 2220 { 2221 int r, was_raw = 0, first = 1; 2222 int asking = options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK; 2223 LogLevel loglevel = asking ? SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_VERBOSE; 2224 char *fp, *response; 2225 size_t i; 2226 struct stat sb; 2227 2228 for (i = 0; i < ctx->nkeys; i++) { 2229 if (!ctx->keys_verified[i]) 2230 continue; 2231 if ((fp = sshkey_fingerprint(ctx->keys[i], 2232 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 2233 fatal_f("sshkey_fingerprint failed"); 2234 if (first && asking) 2235 hostkey_change_preamble(loglevel); 2236 do_log2(loglevel, "Learned new hostkey: %s %s", 2237 sshkey_type(ctx->keys[i]), fp); 2238 first = 0; 2239 free(fp); 2240 } 2241 for (i = 0; i < ctx->nold; i++) { 2242 if ((fp = sshkey_fingerprint(ctx->old_keys[i], 2243 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 2244 fatal_f("sshkey_fingerprint failed"); 2245 if (first && asking) 2246 hostkey_change_preamble(loglevel); 2247 do_log2(loglevel, "Deprecating obsolete hostkey: %s %s", 2248 sshkey_type(ctx->old_keys[i]), fp); 2249 first = 0; 2250 free(fp); 2251 } 2252 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) { 2253 if (get_saved_tio() != NULL) { 2254 leave_raw_mode(1); 2255 was_raw = 1; 2256 } 2257 response = NULL; 2258 for (i = 0; !quit_pending && i < 3; i++) { 2259 free(response); 2260 response = read_passphrase("Accept updated hostkeys? " 2261 "(yes/no): ", RP_ECHO); 2262 if (response != NULL && strcasecmp(response, "yes") == 0) 2263 break; 2264 else if (quit_pending || response == NULL || 2265 strcasecmp(response, "no") == 0) { 2266 options.update_hostkeys = 0; 2267 break; 2268 } else { 2269 do_log2(loglevel, "Please enter " 2270 "\"yes\" or \"no\""); 2271 } 2272 } 2273 if (quit_pending || i >= 3 || response == NULL) 2274 options.update_hostkeys = 0; 2275 free(response); 2276 if (was_raw) 2277 enter_raw_mode(1); 2278 } 2279 if (options.update_hostkeys == 0) 2280 return; 2281 /* 2282 * Now that all the keys are verified, we can go ahead and replace 2283 * them in known_hosts (assuming SSH_UPDATE_HOSTKEYS_ASK didn't 2284 * cancel the operation). 2285 */ 2286 for (i = 0; i < options.num_user_hostfiles; i++) { 2287 /* 2288 * NB. keys are only added to hostfiles[0], for the rest we 2289 * just delete the hostname entries. 2290 */ 2291 if (stat(options.user_hostfiles[i], &sb) != 0) { 2292 if (errno == ENOENT) { 2293 debug_f("known hosts file %s does not " 2294 "exist", options.user_hostfiles[i]); 2295 } else { 2296 error_f("known hosts file %s " 2297 "inaccessible: %s", 2298 options.user_hostfiles[i], strerror(errno)); 2299 } 2300 continue; 2301 } 2302 if ((r = hostfile_replace_entries(options.user_hostfiles[i], 2303 ctx->host_str, ctx->ip_str, 2304 i == 0 ? ctx->keys : NULL, i == 0 ? ctx->nkeys : 0, 2305 options.hash_known_hosts, 0, 2306 options.fingerprint_hash)) != 0) { 2307 error_fr(r, "hostfile_replace_entries failed for %s", 2308 options.user_hostfiles[i]); 2309 } 2310 } 2311 } 2312 2313 static void 2314 client_global_hostkeys_prove_confirm(struct ssh *ssh, int type, 2315 u_int32_t seq, void *_ctx) 2316 { 2317 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 2318 size_t i, ndone; 2319 struct sshbuf *signdata; 2320 int r, plaintype; 2321 const u_char *sig; 2322 const char *rsa_kexalg = NULL; 2323 char *alg = NULL; 2324 size_t siglen; 2325 2326 if (ctx->nnew == 0) 2327 fatal_f("ctx->nnew == 0"); /* sanity */ 2328 if (type != SSH2_MSG_REQUEST_SUCCESS) { 2329 error("Server failed to confirm ownership of " 2330 "private host keys"); 2331 hostkeys_update_ctx_free(ctx); 2332 return; 2333 } 2334 if (sshkey_type_plain(sshkey_type_from_name( 2335 ssh->kex->hostkey_alg)) == KEY_RSA) 2336 rsa_kexalg = ssh->kex->hostkey_alg; 2337 if ((signdata = sshbuf_new()) == NULL) 2338 fatal_f("sshbuf_new failed"); 2339 /* 2340 * Expect a signature for each of the ctx->nnew private keys we 2341 * haven't seen before. They will be in the same order as the 2342 * ctx->keys where the corresponding ctx->keys_match[i] == 0. 2343 */ 2344 for (ndone = i = 0; i < ctx->nkeys; i++) { 2345 if (ctx->keys_match[i]) 2346 continue; 2347 plaintype = sshkey_type_plain(ctx->keys[i]->type); 2348 /* Prepare data to be signed: session ID, unique string, key */ 2349 sshbuf_reset(signdata); 2350 if ( (r = sshbuf_put_cstring(signdata, 2351 "hostkeys-prove-00@openssh.com")) != 0 || 2352 (r = sshbuf_put_stringb(signdata, 2353 ssh->kex->session_id)) != 0 || 2354 (r = sshkey_puts(ctx->keys[i], signdata)) != 0) 2355 fatal_fr(r, "compose signdata"); 2356 /* Extract and verify signature */ 2357 if ((r = sshpkt_get_string_direct(ssh, &sig, &siglen)) != 0) { 2358 error_fr(r, "parse sig"); 2359 goto out; 2360 } 2361 if ((r = sshkey_get_sigtype(sig, siglen, &alg)) != 0) { 2362 error_fr(r, "server gave unintelligible signature " 2363 "for %s key %zu", sshkey_type(ctx->keys[i]), i); 2364 goto out; 2365 } 2366 /* 2367 * Special case for RSA keys: if a RSA hostkey was negotiated, 2368 * then use its signature type for verification of RSA hostkey 2369 * proofs. Otherwise, accept only RSA-SHA256/512 signatures. 2370 */ 2371 if (plaintype == KEY_RSA && rsa_kexalg == NULL && 2372 match_pattern_list(alg, HOSTKEY_PROOF_RSA_ALGS, 0) != 1) { 2373 debug_f("server used untrusted RSA signature algorithm " 2374 "%s for key %zu, disregarding", alg, i); 2375 free(alg); 2376 /* zap the key from the list */ 2377 sshkey_free(ctx->keys[i]); 2378 ctx->keys[i] = NULL; 2379 ndone++; 2380 continue; 2381 } 2382 debug3_f("verify %s key %zu using sigalg %s", 2383 sshkey_type(ctx->keys[i]), i, alg); 2384 free(alg); 2385 if ((r = sshkey_verify(ctx->keys[i], sig, siglen, 2386 sshbuf_ptr(signdata), sshbuf_len(signdata), 2387 plaintype == KEY_RSA ? rsa_kexalg : NULL, 0, NULL)) != 0) { 2388 error_fr(r, "server gave bad signature for %s key %zu", 2389 sshkey_type(ctx->keys[i]), i); 2390 goto out; 2391 } 2392 /* Key is good. Mark it as 'seen' */ 2393 ctx->keys_verified[i] = 1; 2394 ndone++; 2395 } 2396 /* Shouldn't happen */ 2397 if (ndone != ctx->nnew) 2398 fatal_f("ndone != ctx->nnew (%zu / %zu)", ndone, ctx->nnew); 2399 if ((r = sshpkt_get_end(ssh)) != 0) { 2400 error_f("protocol error"); 2401 goto out; 2402 } 2403 2404 /* Make the edits to known_hosts */ 2405 update_known_hosts(ctx); 2406 out: 2407 hostkeys_update_ctx_free(ctx); 2408 hostkeys_update_complete = 1; 2409 client_repledge(); 2410 } 2411 2412 /* 2413 * Handle hostkeys-00@openssh.com global request to inform the client of all 2414 * the server's hostkeys. The keys are checked against the user's 2415 * HostkeyAlgorithms preference before they are accepted. 2416 */ 2417 static int 2418 client_input_hostkeys(struct ssh *ssh) 2419 { 2420 const u_char *blob = NULL; 2421 size_t i, len = 0; 2422 struct sshbuf *buf = NULL; 2423 struct sshkey *key = NULL, **tmp; 2424 int r, prove_sent = 0; 2425 char *fp; 2426 static int hostkeys_seen = 0; /* XXX use struct ssh */ 2427 extern struct sockaddr_storage hostaddr; /* XXX from ssh.c */ 2428 struct hostkeys_update_ctx *ctx = NULL; 2429 u_int want; 2430 2431 if (hostkeys_seen) 2432 fatal_f("server already sent hostkeys"); 2433 if (!can_update_hostkeys()) 2434 return 1; 2435 hostkeys_seen = 1; 2436 2437 ctx = xcalloc(1, sizeof(*ctx)); 2438 while (ssh_packet_remaining(ssh) > 0) { 2439 sshkey_free(key); 2440 key = NULL; 2441 if ((r = sshpkt_get_string_direct(ssh, &blob, &len)) != 0) { 2442 error_fr(r, "parse key"); 2443 goto out; 2444 } 2445 if ((r = sshkey_from_blob(blob, len, &key)) != 0) { 2446 do_log2_fr(r, r == SSH_ERR_KEY_TYPE_UNKNOWN ? 2447 SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_ERROR, 2448 "convert key"); 2449 continue; 2450 } 2451 fp = sshkey_fingerprint(key, options.fingerprint_hash, 2452 SSH_FP_DEFAULT); 2453 debug3_f("received %s key %s", sshkey_type(key), fp); 2454 free(fp); 2455 2456 if (!hostkey_accepted_by_hostkeyalgs(key)) { 2457 debug3_f("%s key not permitted by " 2458 "HostkeyAlgorithms", sshkey_ssh_name(key)); 2459 continue; 2460 } 2461 /* Skip certs */ 2462 if (sshkey_is_cert(key)) { 2463 debug3_f("%s key is a certificate; skipping", 2464 sshkey_ssh_name(key)); 2465 continue; 2466 } 2467 /* Ensure keys are unique */ 2468 for (i = 0; i < ctx->nkeys; i++) { 2469 if (sshkey_equal(key, ctx->keys[i])) { 2470 error_f("received duplicated %s host key", 2471 sshkey_ssh_name(key)); 2472 goto out; 2473 } 2474 } 2475 /* Key is good, record it */ 2476 if ((tmp = recallocarray(ctx->keys, ctx->nkeys, ctx->nkeys + 1, 2477 sizeof(*ctx->keys))) == NULL) 2478 fatal_f("recallocarray failed nkeys = %zu", 2479 ctx->nkeys); 2480 ctx->keys = tmp; 2481 ctx->keys[ctx->nkeys++] = key; 2482 key = NULL; 2483 } 2484 2485 if (ctx->nkeys == 0) { 2486 debug_f("server sent no hostkeys"); 2487 goto out; 2488 } 2489 2490 if ((ctx->keys_match = calloc(ctx->nkeys, 2491 sizeof(*ctx->keys_match))) == NULL || 2492 (ctx->keys_verified = calloc(ctx->nkeys, 2493 sizeof(*ctx->keys_verified))) == NULL) 2494 fatal_f("calloc failed"); 2495 2496 get_hostfile_hostname_ipaddr(host, 2497 options.check_host_ip ? (struct sockaddr *)&hostaddr : NULL, 2498 options.port, &ctx->host_str, 2499 options.check_host_ip ? &ctx->ip_str : NULL); 2500 2501 /* Find which keys we already know about. */ 2502 for (i = 0; i < options.num_user_hostfiles; i++) { 2503 debug_f("searching %s for %s / %s", 2504 options.user_hostfiles[i], ctx->host_str, 2505 ctx->ip_str ? ctx->ip_str : "(none)"); 2506 if ((r = hostkeys_foreach(options.user_hostfiles[i], 2507 hostkeys_find, ctx, ctx->host_str, ctx->ip_str, 2508 HKF_WANT_PARSE_KEY, 0)) != 0) { 2509 if (r == SSH_ERR_SYSTEM_ERROR && errno == ENOENT) { 2510 debug_f("hostkeys file %s does not exist", 2511 options.user_hostfiles[i]); 2512 continue; 2513 } 2514 error_fr(r, "hostkeys_foreach failed for %s", 2515 options.user_hostfiles[i]); 2516 goto out; 2517 } 2518 } 2519 2520 /* Figure out if we have any new keys to add */ 2521 ctx->nnew = ctx->nincomplete = 0; 2522 want = HKF_MATCH_HOST | ( options.check_host_ip ? HKF_MATCH_IP : 0); 2523 for (i = 0; i < ctx->nkeys; i++) { 2524 if (ctx->keys_match[i] == 0) 2525 ctx->nnew++; 2526 if ((ctx->keys_match[i] & want) != want) 2527 ctx->nincomplete++; 2528 } 2529 2530 debug3_f("%zu server keys: %zu new, %zu retained, " 2531 "%zu incomplete match. %zu to remove", ctx->nkeys, ctx->nnew, 2532 ctx->nkeys - ctx->nnew - ctx->nincomplete, 2533 ctx->nincomplete, ctx->nold); 2534 2535 if (ctx->nnew == 0 && ctx->nold == 0) { 2536 debug_f("no new or deprecated keys from server"); 2537 goto out; 2538 } 2539 2540 /* Various reasons why we cannot proceed with the update */ 2541 if (ctx->complex_hostspec) { 2542 debug_f("CA/revocation marker, manual host list or wildcard " 2543 "host pattern found, skipping UserKnownHostsFile update"); 2544 goto out; 2545 } 2546 if (ctx->other_name_seen) { 2547 debug_f("host key found matching a different name/address, " 2548 "skipping UserKnownHostsFile update"); 2549 goto out; 2550 } 2551 /* 2552 * If removing keys, check whether they appear under different 2553 * names/addresses and refuse to proceed if they do. This avoids 2554 * cases such as hosts with multiple names becoming inconsistent 2555 * with regards to CheckHostIP entries. 2556 * XXX UpdateHostkeys=force to override this (and other) checks? 2557 */ 2558 if (ctx->nold != 0) { 2559 if (check_old_keys_othernames(ctx) != 0) 2560 goto out; /* error already logged */ 2561 if (ctx->old_key_seen) { 2562 debug_f("key(s) for %s%s%s exist under other names; " 2563 "skipping UserKnownHostsFile update", 2564 ctx->host_str, ctx->ip_str == NULL ? "" : ",", 2565 ctx->ip_str == NULL ? "" : ctx->ip_str); 2566 goto out; 2567 } 2568 } 2569 2570 if (ctx->nnew == 0) { 2571 /* 2572 * We have some keys to remove or fix matching for. 2573 * We can proceed to do this without requiring a fresh proof 2574 * from the server. 2575 */ 2576 update_known_hosts(ctx); 2577 goto out; 2578 } 2579 /* 2580 * We have received previously-unseen keys from the server. 2581 * Ask the server to confirm ownership of the private halves. 2582 */ 2583 debug3_f("asking server to prove ownership for %zu keys", ctx->nnew); 2584 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 2585 (r = sshpkt_put_cstring(ssh, 2586 "hostkeys-prove-00@openssh.com")) != 0 || 2587 (r = sshpkt_put_u8(ssh, 1)) != 0) /* bool: want reply */ 2588 fatal_fr(r, "prepare hostkeys-prove"); 2589 if ((buf = sshbuf_new()) == NULL) 2590 fatal_f("sshbuf_new"); 2591 for (i = 0; i < ctx->nkeys; i++) { 2592 if (ctx->keys_match[i]) 2593 continue; 2594 sshbuf_reset(buf); 2595 if ((r = sshkey_putb(ctx->keys[i], buf)) != 0 || 2596 (r = sshpkt_put_stringb(ssh, buf)) != 0) 2597 fatal_fr(r, "assemble hostkeys-prove"); 2598 } 2599 if ((r = sshpkt_send(ssh)) != 0) 2600 fatal_fr(r, "send hostkeys-prove"); 2601 client_register_global_confirm( 2602 client_global_hostkeys_prove_confirm, ctx); 2603 ctx = NULL; /* will be freed in callback */ 2604 prove_sent = 1; 2605 2606 /* Success */ 2607 out: 2608 hostkeys_update_ctx_free(ctx); 2609 sshkey_free(key); 2610 sshbuf_free(buf); 2611 if (!prove_sent) { 2612 /* UpdateHostkeys handling completed */ 2613 hostkeys_update_complete = 1; 2614 client_repledge(); 2615 } 2616 /* 2617 * NB. Return success for all cases. The server doesn't need to know 2618 * what the client does with its hosts file. 2619 */ 2620 return 1; 2621 } 2622 2623 static int 2624 client_input_global_request(int type, u_int32_t seq, struct ssh *ssh) 2625 { 2626 char *rtype; 2627 u_char want_reply; 2628 int r, success = 0; 2629 2630 if ((r = sshpkt_get_cstring(ssh, &rtype, NULL)) != 0 || 2631 (r = sshpkt_get_u8(ssh, &want_reply)) != 0) 2632 goto out; 2633 debug("client_input_global_request: rtype %s want_reply %d", 2634 rtype, want_reply); 2635 if (strcmp(rtype, "hostkeys-00@openssh.com") == 0) 2636 success = client_input_hostkeys(ssh); 2637 if (want_reply) { 2638 if ((r = sshpkt_start(ssh, success ? SSH2_MSG_REQUEST_SUCCESS : 2639 SSH2_MSG_REQUEST_FAILURE)) != 0 || 2640 (r = sshpkt_send(ssh)) != 0 || 2641 (r = ssh_packet_write_wait(ssh)) != 0) 2642 goto out; 2643 } 2644 r = 0; 2645 out: 2646 free(rtype); 2647 return r; 2648 } 2649 2650 static void 2651 client_send_env(struct ssh *ssh, int id, const char *name, const char *val) 2652 { 2653 int r; 2654 2655 debug("channel %d: setting env %s = \"%s\"", id, name, val); 2656 channel_request_start(ssh, id, "env", 0); 2657 if ((r = sshpkt_put_cstring(ssh, name)) != 0 || 2658 (r = sshpkt_put_cstring(ssh, val)) != 0 || 2659 (r = sshpkt_send(ssh)) != 0) 2660 fatal_fr(r, "send setenv"); 2661 } 2662 2663 void 2664 client_session2_setup(struct ssh *ssh, int id, int want_tty, int want_subsystem, 2665 const char *term, struct termios *tiop, int in_fd, struct sshbuf *cmd, 2666 char **env) 2667 { 2668 size_t i, j, len; 2669 int matched, r; 2670 char *name, *val; 2671 Channel *c = NULL; 2672 2673 debug2_f("id %d", id); 2674 2675 if ((c = channel_lookup(ssh, id)) == NULL) 2676 fatal_f("channel %d: unknown channel", id); 2677 2678 ssh_packet_set_interactive(ssh, want_tty, 2679 options.ip_qos_interactive, options.ip_qos_bulk); 2680 2681 if (want_tty) { 2682 struct winsize ws; 2683 2684 /* Store window size in the packet. */ 2685 if (ioctl(in_fd, TIOCGWINSZ, &ws) == -1) 2686 memset(&ws, 0, sizeof(ws)); 2687 2688 channel_request_start(ssh, id, "pty-req", 1); 2689 client_expect_confirm(ssh, id, "PTY allocation", CONFIRM_TTY); 2690 if ((r = sshpkt_put_cstring(ssh, term != NULL ? term : "")) 2691 != 0 || 2692 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || 2693 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || 2694 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || 2695 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0) 2696 fatal_fr(r, "build pty-req"); 2697 if (tiop == NULL) 2698 tiop = get_saved_tio(); 2699 ssh_tty_make_modes(ssh, -1, tiop); 2700 if ((r = sshpkt_send(ssh)) != 0) 2701 fatal_fr(r, "send pty-req"); 2702 /* XXX wait for reply */ 2703 c->client_tty = 1; 2704 } 2705 2706 /* Transfer any environment variables from client to server */ 2707 if (options.num_send_env != 0 && env != NULL) { 2708 debug("Sending environment."); 2709 for (i = 0; env[i] != NULL; i++) { 2710 /* Split */ 2711 name = xstrdup(env[i]); 2712 if ((val = strchr(name, '=')) == NULL) { 2713 free(name); 2714 continue; 2715 } 2716 *val++ = '\0'; 2717 2718 matched = 0; 2719 for (j = 0; j < options.num_send_env; j++) { 2720 if (match_pattern(name, options.send_env[j])) { 2721 matched = 1; 2722 break; 2723 } 2724 } 2725 if (!matched) { 2726 debug3("Ignored env %s", name); 2727 free(name); 2728 continue; 2729 } 2730 client_send_env(ssh, id, name, val); 2731 free(name); 2732 } 2733 } 2734 for (i = 0; i < options.num_setenv; i++) { 2735 /* Split */ 2736 name = xstrdup(options.setenv[i]); 2737 if ((val = strchr(name, '=')) == NULL) { 2738 free(name); 2739 continue; 2740 } 2741 *val++ = '\0'; 2742 client_send_env(ssh, id, name, val); 2743 free(name); 2744 } 2745 2746 len = sshbuf_len(cmd); 2747 if (len > 0) { 2748 if (len > 900) 2749 len = 900; 2750 if (want_subsystem) { 2751 debug("Sending subsystem: %.*s", 2752 (int)len, (const u_char*)sshbuf_ptr(cmd)); 2753 channel_request_start(ssh, id, "subsystem", 1); 2754 client_expect_confirm(ssh, id, "subsystem", 2755 CONFIRM_CLOSE); 2756 } else { 2757 debug("Sending command: %.*s", 2758 (int)len, (const u_char*)sshbuf_ptr(cmd)); 2759 channel_request_start(ssh, id, "exec", 1); 2760 client_expect_confirm(ssh, id, "exec", CONFIRM_CLOSE); 2761 } 2762 if ((r = sshpkt_put_stringb(ssh, cmd)) != 0 || 2763 (r = sshpkt_send(ssh)) != 0) 2764 fatal_fr(r, "send command"); 2765 } else { 2766 channel_request_start(ssh, id, "shell", 1); 2767 client_expect_confirm(ssh, id, "shell", CONFIRM_CLOSE); 2768 if ((r = sshpkt_send(ssh)) != 0) 2769 fatal_fr(r, "send shell"); 2770 } 2771 2772 session_setup_complete = 1; 2773 client_repledge(); 2774 } 2775 2776 static void 2777 client_init_dispatch(struct ssh *ssh) 2778 { 2779 ssh_dispatch_init(ssh, &dispatch_protocol_error); 2780 2781 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); 2782 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_DATA, &channel_input_data); 2783 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); 2784 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); 2785 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open); 2786 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 2787 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 2788 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req); 2789 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); 2790 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm); 2791 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm); 2792 ssh_dispatch_set(ssh, SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request); 2793 2794 /* rekeying */ 2795 ssh_dispatch_set(ssh, SSH2_MSG_KEXINIT, &kex_input_kexinit); 2796 2797 /* global request reply messages */ 2798 ssh_dispatch_set(ssh, SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply); 2799 ssh_dispatch_set(ssh, SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply); 2800 } 2801 2802 void 2803 client_stop_mux(void) 2804 { 2805 if (options.control_path != NULL && muxserver_sock != -1) 2806 unlink(options.control_path); 2807 /* 2808 * If we are in persist mode, or don't have a shell, signal that we 2809 * should close when all active channels are closed. 2810 */ 2811 if (options.control_persist || options.session_type == SESSION_TYPE_NONE) { 2812 session_closed = 1; 2813 setproctitle("[stopped mux]"); 2814 } 2815 } 2816 2817 /* client specific fatal cleanup */ 2818 void 2819 cleanup_exit(int i) 2820 { 2821 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 2822 if (options.control_path != NULL && muxserver_sock != -1) 2823 unlink(options.control_path); 2824 ssh_kill_proxy_command(); 2825 _exit(i); 2826 } 2827