1 /* $OpenBSD: clientloop.c,v 1.387 2023/01/06 02:39:59 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 #include "includes.h" 63 64 #include <sys/types.h> 65 #include <sys/ioctl.h> 66 #ifdef HAVE_SYS_STAT_H 67 # include <sys/stat.h> 68 #endif 69 #ifdef HAVE_SYS_TIME_H 70 # include <sys/time.h> 71 #endif 72 #include <sys/socket.h> 73 74 #include <ctype.h> 75 #include <errno.h> 76 #ifdef HAVE_PATHS_H 77 #include <paths.h> 78 #endif 79 #ifdef HAVE_POLL_H 80 #include <poll.h> 81 #endif 82 #include <signal.h> 83 #include <stdio.h> 84 #include <stdlib.h> 85 #include <string.h> 86 #include <stdarg.h> 87 #include <termios.h> 88 #include <pwd.h> 89 #include <unistd.h> 90 #include <limits.h> 91 92 #include "openbsd-compat/sys-queue.h" 93 #include "xmalloc.h" 94 #include "ssh.h" 95 #include "ssh2.h" 96 #include "packet.h" 97 #include "sshbuf.h" 98 #include "compat.h" 99 #include "channels.h" 100 #include "dispatch.h" 101 #include "sshkey.h" 102 #include "cipher.h" 103 #include "kex.h" 104 #include "myproposal.h" 105 #include "log.h" 106 #include "misc.h" 107 #include "readconf.h" 108 #include "clientloop.h" 109 #include "sshconnect.h" 110 #include "authfd.h" 111 #include "atomicio.h" 112 #include "sshpty.h" 113 #include "match.h" 114 #include "msg.h" 115 #include "ssherr.h" 116 #include "hostfile.h" 117 118 /* Permitted RSA signature algorithms for UpdateHostkeys proofs */ 119 #define HOSTKEY_PROOF_RSA_ALGS "rsa-sha2-512,rsa-sha2-256" 120 121 /* import options */ 122 extern Options options; 123 124 /* Control socket */ 125 extern int muxserver_sock; /* XXX use mux_client_cleanup() instead */ 126 127 /* 128 * Name of the host we are connecting to. This is the name given on the 129 * command line, or the Hostname specified for the user-supplied name in a 130 * configuration file. 131 */ 132 extern char *host; 133 134 /* 135 * If this field is not NULL, the ForwardAgent socket is this path and different 136 * instead of SSH_AUTH_SOCK. 137 */ 138 extern char *forward_agent_sock_path; 139 140 /* 141 * Flag to indicate that we have received a window change signal which has 142 * not yet been processed. This will cause a message indicating the new 143 * window size to be sent to the server a little later. This is volatile 144 * because this is updated in a signal handler. 145 */ 146 static volatile sig_atomic_t received_window_change_signal = 0; 147 static volatile sig_atomic_t received_signal = 0; 148 149 /* Time when backgrounded control master using ControlPersist should exit */ 150 static time_t control_persist_exit_time = 0; 151 152 /* Common data for the client loop code. */ 153 volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */ 154 static int last_was_cr; /* Last character was a newline. */ 155 static int exit_status; /* Used to store the command exit status. */ 156 static struct sshbuf *stderr_buffer; /* Used for final exit message. */ 157 static int connection_in; /* Connection to server (input). */ 158 static int connection_out; /* Connection to server (output). */ 159 static int need_rekeying; /* Set to non-zero if rekeying is requested. */ 160 static int session_closed; /* In SSH2: login session closed. */ 161 static u_int x11_refuse_time; /* If >0, refuse x11 opens after this time. */ 162 static time_t server_alive_time; /* Time to do server_alive_check */ 163 static int hostkeys_update_complete; 164 static int session_setup_complete; 165 166 static void client_init_dispatch(struct ssh *ssh); 167 int session_ident = -1; 168 169 /* Track escape per proto2 channel */ 170 struct escape_filter_ctx { 171 int escape_pending; 172 int escape_char; 173 }; 174 175 /* Context for channel confirmation replies */ 176 struct channel_reply_ctx { 177 const char *request_type; 178 int id; 179 enum confirm_action action; 180 }; 181 182 /* Global request success/failure callbacks */ 183 /* XXX move to struct ssh? */ 184 struct global_confirm { 185 TAILQ_ENTRY(global_confirm) entry; 186 global_confirm_cb *cb; 187 void *ctx; 188 int ref_count; 189 }; 190 TAILQ_HEAD(global_confirms, global_confirm); 191 static struct global_confirms global_confirms = 192 TAILQ_HEAD_INITIALIZER(global_confirms); 193 194 void ssh_process_session2_setup(int, int, int, struct sshbuf *); 195 static void quit_message(const char *fmt, ...) 196 __attribute__((__format__ (printf, 1, 2))); 197 198 static void 199 quit_message(const char *fmt, ...) 200 { 201 char *msg; 202 va_list args; 203 int r; 204 205 va_start(args, fmt); 206 xvasprintf(&msg, fmt, args); 207 va_end(args); 208 209 if ((r = sshbuf_putf(stderr_buffer, "%s\r\n", msg)) != 0) 210 fatal_fr(r, "sshbuf_putf"); 211 quit_pending = 1; 212 } 213 214 /* 215 * Signal handler for the window change signal (SIGWINCH). This just sets a 216 * flag indicating that the window has changed. 217 */ 218 /*ARGSUSED */ 219 static void 220 window_change_handler(int sig) 221 { 222 received_window_change_signal = 1; 223 } 224 225 /* 226 * Signal handler for signals that cause the program to terminate. These 227 * signals must be trapped to restore terminal modes. 228 */ 229 /*ARGSUSED */ 230 static void 231 signal_handler(int sig) 232 { 233 received_signal = sig; 234 quit_pending = 1; 235 } 236 237 /* 238 * Sets control_persist_exit_time to the absolute time when the 239 * backgrounded control master should exit due to expiry of the 240 * ControlPersist timeout. Sets it to 0 if we are not a backgrounded 241 * control master process, or if there is no ControlPersist timeout. 242 */ 243 static void 244 set_control_persist_exit_time(struct ssh *ssh) 245 { 246 if (muxserver_sock == -1 || !options.control_persist 247 || options.control_persist_timeout == 0) { 248 /* not using a ControlPersist timeout */ 249 control_persist_exit_time = 0; 250 } else if (channel_still_open(ssh)) { 251 /* some client connections are still open */ 252 if (control_persist_exit_time > 0) 253 debug2_f("cancel scheduled exit"); 254 control_persist_exit_time = 0; 255 } else if (control_persist_exit_time <= 0) { 256 /* a client connection has recently closed */ 257 control_persist_exit_time = monotime() + 258 (time_t)options.control_persist_timeout; 259 debug2_f("schedule exit in %d seconds", 260 options.control_persist_timeout); 261 } 262 /* else we are already counting down to the timeout */ 263 } 264 265 #define SSH_X11_VALID_DISPLAY_CHARS ":/.-_" 266 static int 267 client_x11_display_valid(const char *display) 268 { 269 size_t i, dlen; 270 271 if (display == NULL) 272 return 0; 273 274 dlen = strlen(display); 275 for (i = 0; i < dlen; i++) { 276 if (!isalnum((u_char)display[i]) && 277 strchr(SSH_X11_VALID_DISPLAY_CHARS, display[i]) == NULL) { 278 debug("Invalid character '%c' in DISPLAY", display[i]); 279 return 0; 280 } 281 } 282 return 1; 283 } 284 285 #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1" 286 #define X11_TIMEOUT_SLACK 60 287 int 288 client_x11_get_proto(struct ssh *ssh, const char *display, 289 const char *xauth_path, u_int trusted, u_int timeout, 290 char **_proto, char **_data) 291 { 292 char *cmd, line[512], xdisplay[512]; 293 char xauthfile[PATH_MAX], xauthdir[PATH_MAX]; 294 static char proto[512], data[512]; 295 FILE *f; 296 int got_data = 0, generated = 0, do_unlink = 0, r; 297 struct stat st; 298 u_int now, x11_timeout_real; 299 300 *_proto = proto; 301 *_data = data; 302 proto[0] = data[0] = xauthfile[0] = xauthdir[0] = '\0'; 303 304 if (!client_x11_display_valid(display)) { 305 if (display != NULL) 306 logit("DISPLAY \"%s\" invalid; disabling X11 forwarding", 307 display); 308 return -1; 309 } 310 if (xauth_path != NULL && stat(xauth_path, &st) == -1) { 311 debug("No xauth program."); 312 xauth_path = NULL; 313 } 314 315 if (xauth_path != NULL) { 316 /* 317 * Handle FamilyLocal case where $DISPLAY does 318 * not match an authorization entry. For this we 319 * just try "xauth list unix:displaynum.screennum". 320 * XXX: "localhost" match to determine FamilyLocal 321 * is not perfect. 322 */ 323 if (strncmp(display, "localhost:", 10) == 0) { 324 if ((r = snprintf(xdisplay, sizeof(xdisplay), "unix:%s", 325 display + 10)) < 0 || 326 (size_t)r >= sizeof(xdisplay)) { 327 error_f("display name too long"); 328 return -1; 329 } 330 display = xdisplay; 331 } 332 if (trusted == 0) { 333 /* 334 * Generate an untrusted X11 auth cookie. 335 * 336 * The authentication cookie should briefly outlive 337 * ssh's willingness to forward X11 connections to 338 * avoid nasty fail-open behaviour in the X server. 339 */ 340 mktemp_proto(xauthdir, sizeof(xauthdir)); 341 if (mkdtemp(xauthdir) == NULL) { 342 error_f("mkdtemp: %s", strerror(errno)); 343 return -1; 344 } 345 do_unlink = 1; 346 if ((r = snprintf(xauthfile, sizeof(xauthfile), 347 "%s/xauthfile", xauthdir)) < 0 || 348 (size_t)r >= sizeof(xauthfile)) { 349 error_f("xauthfile path too long"); 350 rmdir(xauthdir); 351 return -1; 352 } 353 354 if (timeout == 0) { 355 /* auth doesn't time out */ 356 xasprintf(&cmd, "%s -f %s generate %s %s " 357 "untrusted 2>%s", 358 xauth_path, xauthfile, display, 359 SSH_X11_PROTO, _PATH_DEVNULL); 360 } else { 361 /* Add some slack to requested expiry */ 362 if (timeout < UINT_MAX - X11_TIMEOUT_SLACK) 363 x11_timeout_real = timeout + 364 X11_TIMEOUT_SLACK; 365 else { 366 /* Don't overflow on long timeouts */ 367 x11_timeout_real = UINT_MAX; 368 } 369 xasprintf(&cmd, "%s -f %s generate %s %s " 370 "untrusted timeout %u 2>%s", 371 xauth_path, xauthfile, display, 372 SSH_X11_PROTO, x11_timeout_real, 373 _PATH_DEVNULL); 374 } 375 debug2_f("xauth command: %s", cmd); 376 377 if (timeout != 0 && x11_refuse_time == 0) { 378 now = monotime() + 1; 379 if (UINT_MAX - timeout < now) 380 x11_refuse_time = UINT_MAX; 381 else 382 x11_refuse_time = now + timeout; 383 channel_set_x11_refuse_time(ssh, 384 x11_refuse_time); 385 } 386 if (system(cmd) == 0) 387 generated = 1; 388 free(cmd); 389 } 390 391 /* 392 * When in untrusted mode, we read the cookie only if it was 393 * successfully generated as an untrusted one in the step 394 * above. 395 */ 396 if (trusted || generated) { 397 xasprintf(&cmd, 398 "%s %s%s list %s 2>" _PATH_DEVNULL, 399 xauth_path, 400 generated ? "-f " : "" , 401 generated ? xauthfile : "", 402 display); 403 debug2("x11_get_proto: %s", cmd); 404 f = popen(cmd, "r"); 405 if (f && fgets(line, sizeof(line), f) && 406 sscanf(line, "%*s %511s %511s", proto, data) == 2) 407 got_data = 1; 408 if (f) 409 pclose(f); 410 free(cmd); 411 } 412 } 413 414 if (do_unlink) { 415 unlink(xauthfile); 416 rmdir(xauthdir); 417 } 418 419 /* Don't fall back to fake X11 data for untrusted forwarding */ 420 if (!trusted && !got_data) { 421 error("Warning: untrusted X11 forwarding setup failed: " 422 "xauth key data not generated"); 423 return -1; 424 } 425 426 /* 427 * If we didn't get authentication data, just make up some 428 * data. The forwarding code will check the validity of the 429 * response anyway, and substitute this data. The X11 430 * server, however, will ignore this fake data and use 431 * whatever authentication mechanisms it was using otherwise 432 * for the local connection. 433 */ 434 if (!got_data) { 435 u_int8_t rnd[16]; 436 u_int i; 437 438 logit("Warning: No xauth data; " 439 "using fake authentication data for X11 forwarding."); 440 strlcpy(proto, SSH_X11_PROTO, sizeof proto); 441 arc4random_buf(rnd, sizeof(rnd)); 442 for (i = 0; i < sizeof(rnd); i++) { 443 snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", 444 rnd[i]); 445 } 446 } 447 448 return 0; 449 } 450 451 /* 452 * Checks if the client window has changed, and sends a packet about it to 453 * the server if so. The actual change is detected elsewhere (by a software 454 * interrupt on Unix); this just checks the flag and sends a message if 455 * appropriate. 456 */ 457 458 static void 459 client_check_window_change(struct ssh *ssh) 460 { 461 if (!received_window_change_signal) 462 return; 463 received_window_change_signal = 0; 464 debug2_f("changed"); 465 channel_send_window_changes(ssh); 466 } 467 468 static int 469 client_global_request_reply(int type, u_int32_t seq, struct ssh *ssh) 470 { 471 struct global_confirm *gc; 472 473 if ((gc = TAILQ_FIRST(&global_confirms)) == NULL) 474 return 0; 475 if (gc->cb != NULL) 476 gc->cb(ssh, type, seq, gc->ctx); 477 if (--gc->ref_count <= 0) { 478 TAILQ_REMOVE(&global_confirms, gc, entry); 479 freezero(gc, sizeof(*gc)); 480 } 481 482 ssh_packet_set_alive_timeouts(ssh, 0); 483 return 0; 484 } 485 486 static void 487 schedule_server_alive_check(void) 488 { 489 if (options.server_alive_interval > 0) 490 server_alive_time = monotime() + options.server_alive_interval; 491 } 492 493 static void 494 server_alive_check(struct ssh *ssh) 495 { 496 int r; 497 498 if (ssh_packet_inc_alive_timeouts(ssh) > options.server_alive_count_max) { 499 logit("Timeout, server %s not responding.", host); 500 cleanup_exit(255); 501 } 502 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 503 (r = sshpkt_put_cstring(ssh, "keepalive@openssh.com")) != 0 || 504 (r = sshpkt_put_u8(ssh, 1)) != 0 || /* boolean: want reply */ 505 (r = sshpkt_send(ssh)) != 0) 506 fatal_fr(r, "send packet"); 507 /* Insert an empty placeholder to maintain ordering */ 508 client_register_global_confirm(NULL, NULL); 509 schedule_server_alive_check(); 510 } 511 512 /* 513 * Waits until the client can do something (some data becomes available on 514 * one of the file descriptors). 515 */ 516 static void 517 client_wait_until_can_do_something(struct ssh *ssh, struct pollfd **pfdp, 518 u_int *npfd_allocp, u_int *npfd_activep, int rekeying, 519 int *conn_in_readyp, int *conn_out_readyp) 520 { 521 struct timespec timeout; 522 int ret; 523 u_int p; 524 525 *conn_in_readyp = *conn_out_readyp = 0; 526 527 /* Prepare channel poll. First two pollfd entries are reserved */ 528 ptimeout_init(&timeout); 529 channel_prepare_poll(ssh, pfdp, npfd_allocp, npfd_activep, 2, &timeout); 530 if (*npfd_activep < 2) 531 fatal_f("bad npfd %u", *npfd_activep); /* shouldn't happen */ 532 533 /* channel_prepare_poll could have closed the last channel */ 534 if (session_closed && !channel_still_open(ssh) && 535 !ssh_packet_have_data_to_write(ssh)) { 536 /* clear events since we did not call poll() */ 537 for (p = 0; p < *npfd_activep; p++) 538 (*pfdp)[p].revents = 0; 539 return; 540 } 541 542 /* Monitor server connection on reserved pollfd entries */ 543 (*pfdp)[0].fd = connection_in; 544 (*pfdp)[0].events = POLLIN; 545 (*pfdp)[1].fd = connection_out; 546 (*pfdp)[1].events = ssh_packet_have_data_to_write(ssh) ? POLLOUT : 0; 547 548 /* 549 * Wait for something to happen. This will suspend the process until 550 * some polled descriptor can be read, written, or has some other 551 * event pending, or a timeout expires. 552 */ 553 set_control_persist_exit_time(ssh); 554 if (control_persist_exit_time > 0) 555 ptimeout_deadline_monotime(&timeout, control_persist_exit_time); 556 if (options.server_alive_interval > 0) 557 ptimeout_deadline_monotime(&timeout, server_alive_time); 558 if (options.rekey_interval > 0 && !rekeying) { 559 ptimeout_deadline_sec(&timeout, 560 ssh_packet_get_rekey_timeout(ssh)); 561 } 562 563 ret = poll(*pfdp, *npfd_activep, ptimeout_get_ms(&timeout)); 564 565 if (ret == -1) { 566 /* 567 * We have to clear the events because we return. 568 * We have to return, because the mainloop checks for the flags 569 * set by the signal handlers. 570 */ 571 for (p = 0; p < *npfd_activep; p++) 572 (*pfdp)[p].revents = 0; 573 if (errno == EINTR) 574 return; 575 /* Note: we might still have data in the buffers. */ 576 quit_message("poll: %s", strerror(errno)); 577 return; 578 } 579 580 *conn_in_readyp = (*pfdp)[0].revents != 0; 581 *conn_out_readyp = (*pfdp)[1].revents != 0; 582 583 if (options.server_alive_interval > 0 && !*conn_in_readyp && 584 monotime() >= server_alive_time) { 585 /* 586 * ServerAlive check is needed. We can't rely on the poll 587 * timing out since traffic on the client side such as port 588 * forwards can keep waking it up. 589 */ 590 server_alive_check(ssh); 591 } 592 } 593 594 static void 595 client_suspend_self(struct sshbuf *bin, struct sshbuf *bout, struct sshbuf *berr) 596 { 597 /* Flush stdout and stderr buffers. */ 598 if (sshbuf_len(bout) > 0) 599 atomicio(vwrite, fileno(stdout), sshbuf_mutable_ptr(bout), 600 sshbuf_len(bout)); 601 if (sshbuf_len(berr) > 0) 602 atomicio(vwrite, fileno(stderr), sshbuf_mutable_ptr(berr), 603 sshbuf_len(berr)); 604 605 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 606 607 sshbuf_reset(bin); 608 sshbuf_reset(bout); 609 sshbuf_reset(berr); 610 611 /* Send the suspend signal to the program itself. */ 612 kill(getpid(), SIGTSTP); 613 614 /* Reset window sizes in case they have changed */ 615 received_window_change_signal = 1; 616 617 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 618 } 619 620 static void 621 client_process_net_input(struct ssh *ssh) 622 { 623 int r; 624 625 /* 626 * Read input from the server, and add any such data to the buffer of 627 * the packet subsystem. 628 */ 629 schedule_server_alive_check(); 630 if ((r = ssh_packet_process_read(ssh, connection_in)) == 0) 631 return; /* success */ 632 if (r == SSH_ERR_SYSTEM_ERROR) { 633 if (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK) 634 return; 635 if (errno == EPIPE) { 636 quit_message("Connection to %s closed by remote host.", 637 host); 638 return; 639 } 640 } 641 quit_message("Read from remote host %s: %s", host, ssh_err(r)); 642 } 643 644 static void 645 client_status_confirm(struct ssh *ssh, int type, Channel *c, void *ctx) 646 { 647 struct channel_reply_ctx *cr = (struct channel_reply_ctx *)ctx; 648 char errmsg[256]; 649 int r, tochan; 650 651 /* 652 * If a TTY was explicitly requested, then a failure to allocate 653 * one is fatal. 654 */ 655 if (cr->action == CONFIRM_TTY && 656 (options.request_tty == REQUEST_TTY_FORCE || 657 options.request_tty == REQUEST_TTY_YES)) 658 cr->action = CONFIRM_CLOSE; 659 660 /* XXX suppress on mux _client_ quietmode */ 661 tochan = options.log_level >= SYSLOG_LEVEL_ERROR && 662 c->ctl_chan != -1 && c->extended_usage == CHAN_EXTENDED_WRITE; 663 664 if (type == SSH2_MSG_CHANNEL_SUCCESS) { 665 debug2("%s request accepted on channel %d", 666 cr->request_type, c->self); 667 } else if (type == SSH2_MSG_CHANNEL_FAILURE) { 668 if (tochan) { 669 snprintf(errmsg, sizeof(errmsg), 670 "%s request failed\r\n", cr->request_type); 671 } else { 672 snprintf(errmsg, sizeof(errmsg), 673 "%s request failed on channel %d", 674 cr->request_type, c->self); 675 } 676 /* If error occurred on primary session channel, then exit */ 677 if (cr->action == CONFIRM_CLOSE && c->self == session_ident) 678 fatal("%s", errmsg); 679 /* 680 * If error occurred on mux client, append to 681 * their stderr. 682 */ 683 if (tochan) { 684 debug3_f("channel %d: mux request: %s", c->self, 685 cr->request_type); 686 if ((r = sshbuf_put(c->extended, errmsg, 687 strlen(errmsg))) != 0) 688 fatal_fr(r, "sshbuf_put"); 689 } else 690 error("%s", errmsg); 691 if (cr->action == CONFIRM_TTY) { 692 /* 693 * If a TTY allocation error occurred, then arrange 694 * for the correct TTY to leave raw mode. 695 */ 696 if (c->self == session_ident) 697 leave_raw_mode(0); 698 else 699 mux_tty_alloc_failed(ssh, c); 700 } else if (cr->action == CONFIRM_CLOSE) { 701 chan_read_failed(ssh, c); 702 chan_write_failed(ssh, c); 703 } 704 } 705 free(cr); 706 } 707 708 static void 709 client_abandon_status_confirm(struct ssh *ssh, Channel *c, void *ctx) 710 { 711 free(ctx); 712 } 713 714 void 715 client_expect_confirm(struct ssh *ssh, int id, const char *request, 716 enum confirm_action action) 717 { 718 struct channel_reply_ctx *cr = xcalloc(1, sizeof(*cr)); 719 720 cr->request_type = request; 721 cr->action = action; 722 723 channel_register_status_confirm(ssh, id, client_status_confirm, 724 client_abandon_status_confirm, cr); 725 } 726 727 void 728 client_register_global_confirm(global_confirm_cb *cb, void *ctx) 729 { 730 struct global_confirm *gc, *last_gc; 731 732 /* Coalesce identical callbacks */ 733 last_gc = TAILQ_LAST(&global_confirms, global_confirms); 734 if (last_gc && last_gc->cb == cb && last_gc->ctx == ctx) { 735 if (++last_gc->ref_count >= INT_MAX) 736 fatal_f("last_gc->ref_count = %d", 737 last_gc->ref_count); 738 return; 739 } 740 741 gc = xcalloc(1, sizeof(*gc)); 742 gc->cb = cb; 743 gc->ctx = ctx; 744 gc->ref_count = 1; 745 TAILQ_INSERT_TAIL(&global_confirms, gc, entry); 746 } 747 748 /* 749 * Returns non-zero if the client is able to handle a hostkeys-00@openssh.com 750 * hostkey update request. 751 */ 752 static int 753 can_update_hostkeys(void) 754 { 755 if (hostkeys_update_complete) 756 return 0; 757 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK && 758 options.batch_mode) 759 return 0; /* won't ask in batchmode, so don't even try */ 760 if (!options.update_hostkeys || options.num_user_hostfiles <= 0) 761 return 0; 762 return 1; 763 } 764 765 static void 766 client_repledge(void) 767 { 768 debug3_f("enter"); 769 770 /* Might be able to tighten pledge now that session is established */ 771 if (options.control_master || options.control_path != NULL || 772 options.forward_x11 || options.fork_after_authentication || 773 can_update_hostkeys() || 774 (session_ident != -1 && !session_setup_complete)) { 775 /* Can't tighten */ 776 return; 777 } 778 /* 779 * LocalCommand and UpdateHostkeys have finished, so can get rid of 780 * filesystem. 781 * 782 * XXX protocol allows a server can to change hostkeys during the 783 * connection at rekey time that could trigger a hostkeys update 784 * but AFAIK no implementations support this. Could improve by 785 * forcing known_hosts to be read-only or via unveil(2). 786 */ 787 if (options.num_local_forwards != 0 || 788 options.num_remote_forwards != 0 || 789 options.num_permitted_remote_opens != 0 || 790 options.enable_escape_commandline != 0) { 791 /* rfwd needs inet */ 792 debug("pledge: network"); 793 if (pledge("stdio unix inet dns proc tty", NULL) == -1) 794 fatal_f("pledge(): %s", strerror(errno)); 795 } else if (options.forward_agent != 0) { 796 /* agent forwarding needs to open $SSH_AUTH_SOCK at will */ 797 debug("pledge: agent"); 798 if (pledge("stdio unix proc tty", NULL) == -1) 799 fatal_f("pledge(): %s", strerror(errno)); 800 } else { 801 debug("pledge: fork"); 802 if (pledge("stdio proc tty", NULL) == -1) 803 fatal_f("pledge(): %s", strerror(errno)); 804 } 805 /* XXX further things to do: 806 * 807 * - might be able to get rid of proc if we kill ~^Z 808 * - ssh -N (no session) 809 * - stdio forwarding 810 * - sessions without tty 811 */ 812 } 813 814 static void 815 process_cmdline(struct ssh *ssh) 816 { 817 void (*handler)(int); 818 char *s, *cmd; 819 int ok, delete = 0, local = 0, remote = 0, dynamic = 0; 820 struct Forward fwd; 821 822 memset(&fwd, 0, sizeof(fwd)); 823 824 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 825 handler = ssh_signal(SIGINT, SIG_IGN); 826 cmd = s = read_passphrase("\r\nssh> ", RP_ECHO); 827 if (s == NULL) 828 goto out; 829 while (isspace((u_char)*s)) 830 s++; 831 if (*s == '-') 832 s++; /* Skip cmdline '-', if any */ 833 if (*s == '\0') 834 goto out; 835 836 if (*s == 'h' || *s == 'H' || *s == '?') { 837 logit("Commands:"); 838 logit(" -L[bind_address:]port:host:hostport " 839 "Request local forward"); 840 logit(" -R[bind_address:]port:host:hostport " 841 "Request remote forward"); 842 logit(" -D[bind_address:]port " 843 "Request dynamic forward"); 844 logit(" -KL[bind_address:]port " 845 "Cancel local forward"); 846 logit(" -KR[bind_address:]port " 847 "Cancel remote forward"); 848 logit(" -KD[bind_address:]port " 849 "Cancel dynamic forward"); 850 if (!options.permit_local_command) 851 goto out; 852 logit(" !args " 853 "Execute local command"); 854 goto out; 855 } 856 857 if (*s == '!' && options.permit_local_command) { 858 s++; 859 ssh_local_cmd(s); 860 goto out; 861 } 862 863 if (*s == 'K') { 864 delete = 1; 865 s++; 866 } 867 if (*s == 'L') 868 local = 1; 869 else if (*s == 'R') 870 remote = 1; 871 else if (*s == 'D') 872 dynamic = 1; 873 else { 874 logit("Invalid command."); 875 goto out; 876 } 877 878 while (isspace((u_char)*++s)) 879 ; 880 881 /* XXX update list of forwards in options */ 882 if (delete) { 883 /* We pass 1 for dynamicfwd to restrict to 1 or 2 fields. */ 884 if (!parse_forward(&fwd, s, 1, 0)) { 885 logit("Bad forwarding close specification."); 886 goto out; 887 } 888 if (remote) 889 ok = channel_request_rforward_cancel(ssh, &fwd) == 0; 890 else if (dynamic) 891 ok = channel_cancel_lport_listener(ssh, &fwd, 892 0, &options.fwd_opts) > 0; 893 else 894 ok = channel_cancel_lport_listener(ssh, &fwd, 895 CHANNEL_CANCEL_PORT_STATIC, 896 &options.fwd_opts) > 0; 897 if (!ok) { 898 logit("Unknown port forwarding."); 899 goto out; 900 } 901 logit("Canceled forwarding."); 902 } else { 903 /* -R specs can be both dynamic or not, so check both. */ 904 if (remote) { 905 if (!parse_forward(&fwd, s, 0, remote) && 906 !parse_forward(&fwd, s, 1, remote)) { 907 logit("Bad remote forwarding specification."); 908 goto out; 909 } 910 } else if (!parse_forward(&fwd, s, dynamic, remote)) { 911 logit("Bad local forwarding specification."); 912 goto out; 913 } 914 if (local || dynamic) { 915 if (!channel_setup_local_fwd_listener(ssh, &fwd, 916 &options.fwd_opts)) { 917 logit("Port forwarding failed."); 918 goto out; 919 } 920 } else { 921 if (channel_request_remote_forwarding(ssh, &fwd) < 0) { 922 logit("Port forwarding failed."); 923 goto out; 924 } 925 } 926 logit("Forwarding port."); 927 } 928 929 out: 930 ssh_signal(SIGINT, handler); 931 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 932 free(cmd); 933 free(fwd.listen_host); 934 free(fwd.listen_path); 935 free(fwd.connect_host); 936 free(fwd.connect_path); 937 } 938 939 /* reasons to suppress output of an escape command in help output */ 940 #define SUPPRESS_NEVER 0 /* never suppress, always show */ 941 #define SUPPRESS_MUXCLIENT 1 /* don't show in mux client sessions */ 942 #define SUPPRESS_MUXMASTER 2 /* don't show in mux master sessions */ 943 #define SUPPRESS_SYSLOG 4 /* don't show when logging to syslog */ 944 #define SUPPRESS_NOCMDLINE 8 /* don't show when cmdline disabled*/ 945 struct escape_help_text { 946 const char *cmd; 947 const char *text; 948 unsigned int flags; 949 }; 950 static struct escape_help_text esc_txt[] = { 951 {".", "terminate session", SUPPRESS_MUXMASTER}, 952 {".", "terminate connection (and any multiplexed sessions)", 953 SUPPRESS_MUXCLIENT}, 954 {"B", "send a BREAK to the remote system", SUPPRESS_NEVER}, 955 {"C", "open a command line", SUPPRESS_MUXCLIENT|SUPPRESS_NOCMDLINE}, 956 {"R", "request rekey", SUPPRESS_NEVER}, 957 {"V/v", "decrease/increase verbosity (LogLevel)", SUPPRESS_MUXCLIENT}, 958 {"^Z", "suspend ssh", SUPPRESS_MUXCLIENT}, 959 {"#", "list forwarded connections", SUPPRESS_NEVER}, 960 {"&", "background ssh (when waiting for connections to terminate)", 961 SUPPRESS_MUXCLIENT}, 962 {"?", "this message", SUPPRESS_NEVER}, 963 }; 964 965 static void 966 print_escape_help(struct sshbuf *b, int escape_char, int mux_client, 967 int using_stderr) 968 { 969 unsigned int i, suppress_flags; 970 int r; 971 972 if ((r = sshbuf_putf(b, 973 "%c?\r\nSupported escape sequences:\r\n", escape_char)) != 0) 974 fatal_fr(r, "sshbuf_putf"); 975 976 suppress_flags = 977 (mux_client ? SUPPRESS_MUXCLIENT : 0) | 978 (mux_client ? 0 : SUPPRESS_MUXMASTER) | 979 (using_stderr ? 0 : SUPPRESS_SYSLOG) | 980 (options.enable_escape_commandline == 0 ? SUPPRESS_NOCMDLINE : 0); 981 982 for (i = 0; i < sizeof(esc_txt)/sizeof(esc_txt[0]); i++) { 983 if (esc_txt[i].flags & suppress_flags) 984 continue; 985 if ((r = sshbuf_putf(b, " %c%-3s - %s\r\n", 986 escape_char, esc_txt[i].cmd, esc_txt[i].text)) != 0) 987 fatal_fr(r, "sshbuf_putf"); 988 } 989 990 if ((r = sshbuf_putf(b, 991 " %c%c - send the escape character by typing it twice\r\n" 992 "(Note that escapes are only recognized immediately after " 993 "newline.)\r\n", escape_char, escape_char)) != 0) 994 fatal_fr(r, "sshbuf_putf"); 995 } 996 997 /* 998 * Process the characters one by one. 999 */ 1000 static int 1001 process_escapes(struct ssh *ssh, Channel *c, 1002 struct sshbuf *bin, struct sshbuf *bout, struct sshbuf *berr, 1003 char *buf, int len) 1004 { 1005 pid_t pid; 1006 int r, bytes = 0; 1007 u_int i; 1008 u_char ch; 1009 char *s; 1010 struct escape_filter_ctx *efc = c->filter_ctx == NULL ? 1011 NULL : (struct escape_filter_ctx *)c->filter_ctx; 1012 1013 if (c->filter_ctx == NULL) 1014 return 0; 1015 1016 if (len <= 0) 1017 return (0); 1018 1019 for (i = 0; i < (u_int)len; i++) { 1020 /* Get one character at a time. */ 1021 ch = buf[i]; 1022 1023 if (efc->escape_pending) { 1024 /* We have previously seen an escape character. */ 1025 /* Clear the flag now. */ 1026 efc->escape_pending = 0; 1027 1028 /* Process the escaped character. */ 1029 switch (ch) { 1030 case '.': 1031 /* Terminate the connection. */ 1032 if ((r = sshbuf_putf(berr, "%c.\r\n", 1033 efc->escape_char)) != 0) 1034 fatal_fr(r, "sshbuf_putf"); 1035 if (c && c->ctl_chan != -1) { 1036 channel_force_close(ssh, c, 1); 1037 return 0; 1038 } else 1039 quit_pending = 1; 1040 return -1; 1041 1042 case 'Z' - 64: 1043 /* XXX support this for mux clients */ 1044 if (c && c->ctl_chan != -1) { 1045 char b[16]; 1046 noescape: 1047 if (ch == 'Z' - 64) 1048 snprintf(b, sizeof b, "^Z"); 1049 else 1050 snprintf(b, sizeof b, "%c", ch); 1051 if ((r = sshbuf_putf(berr, 1052 "%c%s escape not available to " 1053 "multiplexed sessions\r\n", 1054 efc->escape_char, b)) != 0) 1055 fatal_fr(r, "sshbuf_putf"); 1056 continue; 1057 } 1058 /* Suspend the program. Inform the user */ 1059 if ((r = sshbuf_putf(berr, 1060 "%c^Z [suspend ssh]\r\n", 1061 efc->escape_char)) != 0) 1062 fatal_fr(r, "sshbuf_putf"); 1063 1064 /* Restore terminal modes and suspend. */ 1065 client_suspend_self(bin, bout, berr); 1066 1067 /* We have been continued. */ 1068 continue; 1069 1070 case 'B': 1071 if ((r = sshbuf_putf(berr, 1072 "%cB\r\n", efc->escape_char)) != 0) 1073 fatal_fr(r, "sshbuf_putf"); 1074 channel_request_start(ssh, c->self, "break", 0); 1075 if ((r = sshpkt_put_u32(ssh, 1000)) != 0 || 1076 (r = sshpkt_send(ssh)) != 0) 1077 fatal_fr(r, "send packet"); 1078 continue; 1079 1080 case 'R': 1081 if (ssh->compat & SSH_BUG_NOREKEY) 1082 logit("Server does not " 1083 "support re-keying"); 1084 else 1085 need_rekeying = 1; 1086 continue; 1087 1088 case 'V': 1089 /* FALLTHROUGH */ 1090 case 'v': 1091 if (c && c->ctl_chan != -1) 1092 goto noescape; 1093 if (!log_is_on_stderr()) { 1094 if ((r = sshbuf_putf(berr, 1095 "%c%c [Logging to syslog]\r\n", 1096 efc->escape_char, ch)) != 0) 1097 fatal_fr(r, "sshbuf_putf"); 1098 continue; 1099 } 1100 if (ch == 'V' && options.log_level > 1101 SYSLOG_LEVEL_QUIET) 1102 log_change_level(--options.log_level); 1103 if (ch == 'v' && options.log_level < 1104 SYSLOG_LEVEL_DEBUG3) 1105 log_change_level(++options.log_level); 1106 if ((r = sshbuf_putf(berr, 1107 "%c%c [LogLevel %s]\r\n", 1108 efc->escape_char, ch, 1109 log_level_name(options.log_level))) != 0) 1110 fatal_fr(r, "sshbuf_putf"); 1111 continue; 1112 1113 case '&': 1114 if (c && c->ctl_chan != -1) 1115 goto noescape; 1116 /* 1117 * Detach the program (continue to serve 1118 * connections, but put in background and no 1119 * more new connections). 1120 */ 1121 /* Restore tty modes. */ 1122 leave_raw_mode( 1123 options.request_tty == REQUEST_TTY_FORCE); 1124 1125 /* Stop listening for new connections. */ 1126 channel_stop_listening(ssh); 1127 1128 if ((r = sshbuf_putf(berr, "%c& " 1129 "[backgrounded]\n", efc->escape_char)) != 0) 1130 fatal_fr(r, "sshbuf_putf"); 1131 1132 /* Fork into background. */ 1133 pid = fork(); 1134 if (pid == -1) { 1135 error("fork: %.100s", strerror(errno)); 1136 continue; 1137 } 1138 if (pid != 0) { /* This is the parent. */ 1139 /* The parent just exits. */ 1140 exit(0); 1141 } 1142 /* The child continues serving connections. */ 1143 /* fake EOF on stdin */ 1144 if ((r = sshbuf_put_u8(bin, 4)) != 0) 1145 fatal_fr(r, "sshbuf_put_u8"); 1146 return -1; 1147 case '?': 1148 print_escape_help(berr, efc->escape_char, 1149 (c && c->ctl_chan != -1), 1150 log_is_on_stderr()); 1151 continue; 1152 1153 case '#': 1154 if ((r = sshbuf_putf(berr, "%c#\r\n", 1155 efc->escape_char)) != 0) 1156 fatal_fr(r, "sshbuf_putf"); 1157 s = channel_open_message(ssh); 1158 if ((r = sshbuf_put(berr, s, strlen(s))) != 0) 1159 fatal_fr(r, "sshbuf_put"); 1160 free(s); 1161 continue; 1162 1163 case 'C': 1164 if (c && c->ctl_chan != -1) 1165 goto noescape; 1166 if (options.enable_escape_commandline == 0) { 1167 if ((r = sshbuf_putf(berr, 1168 "commandline disabled\r\n")) != 0) 1169 fatal_fr(r, "sshbuf_putf"); 1170 continue; 1171 } 1172 process_cmdline(ssh); 1173 continue; 1174 1175 default: 1176 if (ch != efc->escape_char) { 1177 if ((r = sshbuf_put_u8(bin, 1178 efc->escape_char)) != 0) 1179 fatal_fr(r, "sshbuf_put_u8"); 1180 bytes++; 1181 } 1182 /* Escaped characters fall through here */ 1183 break; 1184 } 1185 } else { 1186 /* 1187 * The previous character was not an escape char. 1188 * Check if this is an escape. 1189 */ 1190 if (last_was_cr && ch == efc->escape_char) { 1191 /* 1192 * It is. Set the flag and continue to 1193 * next character. 1194 */ 1195 efc->escape_pending = 1; 1196 continue; 1197 } 1198 } 1199 1200 /* 1201 * Normal character. Record whether it was a newline, 1202 * and append it to the buffer. 1203 */ 1204 last_was_cr = (ch == '\r' || ch == '\n'); 1205 if ((r = sshbuf_put_u8(bin, ch)) != 0) 1206 fatal_fr(r, "sshbuf_put_u8"); 1207 bytes++; 1208 } 1209 return bytes; 1210 } 1211 1212 /* 1213 * Get packets from the connection input buffer, and process them as long as 1214 * there are packets available. 1215 * 1216 * Any unknown packets received during the actual 1217 * session cause the session to terminate. This is 1218 * intended to make debugging easier since no 1219 * confirmations are sent. Any compatible protocol 1220 * extensions must be negotiated during the 1221 * preparatory phase. 1222 */ 1223 1224 static void 1225 client_process_buffered_input_packets(struct ssh *ssh) 1226 { 1227 ssh_dispatch_run_fatal(ssh, DISPATCH_NONBLOCK, &quit_pending); 1228 } 1229 1230 /* scan buf[] for '~' before sending data to the peer */ 1231 1232 /* Helper: allocate a new escape_filter_ctx and fill in its escape char */ 1233 void * 1234 client_new_escape_filter_ctx(int escape_char) 1235 { 1236 struct escape_filter_ctx *ret; 1237 1238 ret = xcalloc(1, sizeof(*ret)); 1239 ret->escape_pending = 0; 1240 ret->escape_char = escape_char; 1241 return (void *)ret; 1242 } 1243 1244 /* Free the escape filter context on channel free */ 1245 void 1246 client_filter_cleanup(struct ssh *ssh, int cid, void *ctx) 1247 { 1248 free(ctx); 1249 } 1250 1251 int 1252 client_simple_escape_filter(struct ssh *ssh, Channel *c, char *buf, int len) 1253 { 1254 if (c->extended_usage != CHAN_EXTENDED_WRITE) 1255 return 0; 1256 1257 return process_escapes(ssh, c, c->input, c->output, c->extended, 1258 buf, len); 1259 } 1260 1261 static void 1262 client_channel_closed(struct ssh *ssh, int id, int force, void *arg) 1263 { 1264 channel_cancel_cleanup(ssh, id); 1265 session_closed = 1; 1266 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1267 } 1268 1269 /* 1270 * Implements the interactive session with the server. This is called after 1271 * the user has been authenticated, and a command has been started on the 1272 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character 1273 * used as an escape character for terminating or suspending the session. 1274 */ 1275 int 1276 client_loop(struct ssh *ssh, int have_pty, int escape_char_arg, 1277 int ssh2_chan_id) 1278 { 1279 struct pollfd *pfd = NULL; 1280 u_int npfd_alloc = 0, npfd_active = 0; 1281 double start_time, total_time; 1282 int r, len; 1283 u_int64_t ibytes, obytes; 1284 int conn_in_ready, conn_out_ready; 1285 1286 debug("Entering interactive session."); 1287 session_ident = ssh2_chan_id; 1288 1289 if (options.control_master && 1290 !option_clear_or_none(options.control_path)) { 1291 debug("pledge: id"); 1292 if (pledge("stdio rpath wpath cpath unix inet dns recvfd sendfd proc exec id tty", 1293 NULL) == -1) 1294 fatal_f("pledge(): %s", strerror(errno)); 1295 1296 } else if (options.forward_x11 || options.permit_local_command) { 1297 debug("pledge: exec"); 1298 if (pledge("stdio rpath wpath cpath unix inet dns proc exec tty", 1299 NULL) == -1) 1300 fatal_f("pledge(): %s", strerror(errno)); 1301 1302 } else if (options.update_hostkeys) { 1303 debug("pledge: filesystem"); 1304 if (pledge("stdio rpath wpath cpath unix inet dns proc tty", 1305 NULL) == -1) 1306 fatal_f("pledge(): %s", strerror(errno)); 1307 1308 } else if (!option_clear_or_none(options.proxy_command) || 1309 options.fork_after_authentication) { 1310 debug("pledge: proc"); 1311 if (pledge("stdio cpath unix inet dns proc tty", NULL) == -1) 1312 fatal_f("pledge(): %s", strerror(errno)); 1313 1314 } else { 1315 debug("pledge: network"); 1316 if (pledge("stdio unix inet dns proc tty", NULL) == -1) 1317 fatal_f("pledge(): %s", strerror(errno)); 1318 } 1319 1320 /* might be able to tighten now */ 1321 client_repledge(); 1322 1323 start_time = monotime_double(); 1324 1325 /* Initialize variables. */ 1326 last_was_cr = 1; 1327 exit_status = -1; 1328 connection_in = ssh_packet_get_connection_in(ssh); 1329 connection_out = ssh_packet_get_connection_out(ssh); 1330 1331 quit_pending = 0; 1332 1333 /* Initialize buffer. */ 1334 if ((stderr_buffer = sshbuf_new()) == NULL) 1335 fatal_f("sshbuf_new failed"); 1336 1337 client_init_dispatch(ssh); 1338 1339 /* 1340 * Set signal handlers, (e.g. to restore non-blocking mode) 1341 * but don't overwrite SIG_IGN, matches behaviour from rsh(1) 1342 */ 1343 if (ssh_signal(SIGHUP, SIG_IGN) != SIG_IGN) 1344 ssh_signal(SIGHUP, signal_handler); 1345 if (ssh_signal(SIGINT, SIG_IGN) != SIG_IGN) 1346 ssh_signal(SIGINT, signal_handler); 1347 if (ssh_signal(SIGQUIT, SIG_IGN) != SIG_IGN) 1348 ssh_signal(SIGQUIT, signal_handler); 1349 if (ssh_signal(SIGTERM, SIG_IGN) != SIG_IGN) 1350 ssh_signal(SIGTERM, signal_handler); 1351 ssh_signal(SIGWINCH, window_change_handler); 1352 1353 if (have_pty) 1354 enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1355 1356 if (session_ident != -1) { 1357 if (escape_char_arg != SSH_ESCAPECHAR_NONE) { 1358 channel_register_filter(ssh, session_ident, 1359 client_simple_escape_filter, NULL, 1360 client_filter_cleanup, 1361 client_new_escape_filter_ctx( 1362 escape_char_arg)); 1363 } 1364 channel_register_cleanup(ssh, session_ident, 1365 client_channel_closed, 0); 1366 } 1367 1368 schedule_server_alive_check(); 1369 1370 /* Main loop of the client for the interactive session mode. */ 1371 while (!quit_pending) { 1372 1373 /* Process buffered packets sent by the server. */ 1374 client_process_buffered_input_packets(ssh); 1375 1376 if (session_closed && !channel_still_open(ssh)) 1377 break; 1378 1379 if (ssh_packet_is_rekeying(ssh)) { 1380 debug("rekeying in progress"); 1381 } else if (need_rekeying) { 1382 /* manual rekey request */ 1383 debug("need rekeying"); 1384 if ((r = kex_start_rekex(ssh)) != 0) 1385 fatal_fr(r, "kex_start_rekex"); 1386 need_rekeying = 0; 1387 } else { 1388 /* 1389 * Make packets from buffered channel data, and 1390 * enqueue them for sending to the server. 1391 */ 1392 if (ssh_packet_not_very_much_data_to_write(ssh)) 1393 channel_output_poll(ssh); 1394 1395 /* 1396 * Check if the window size has changed, and buffer a 1397 * message about it to the server if so. 1398 */ 1399 client_check_window_change(ssh); 1400 1401 if (quit_pending) 1402 break; 1403 } 1404 /* 1405 * Wait until we have something to do (something becomes 1406 * available on one of the descriptors). 1407 */ 1408 client_wait_until_can_do_something(ssh, &pfd, &npfd_alloc, 1409 &npfd_active, ssh_packet_is_rekeying(ssh), 1410 &conn_in_ready, &conn_out_ready); 1411 1412 if (quit_pending) 1413 break; 1414 1415 /* Do channel operations. */ 1416 channel_after_poll(ssh, pfd, npfd_active); 1417 1418 /* Buffer input from the connection. */ 1419 if (conn_in_ready) 1420 client_process_net_input(ssh); 1421 1422 if (quit_pending) 1423 break; 1424 1425 /* A timeout may have triggered rekeying */ 1426 if ((r = ssh_packet_check_rekey(ssh)) != 0) 1427 fatal_fr(r, "cannot start rekeying"); 1428 1429 /* 1430 * Send as much buffered packet data as possible to the 1431 * sender. 1432 */ 1433 if (conn_out_ready) { 1434 if ((r = ssh_packet_write_poll(ssh)) != 0) { 1435 sshpkt_fatal(ssh, r, 1436 "%s: ssh_packet_write_poll", __func__); 1437 } 1438 } 1439 1440 /* 1441 * If we are a backgrounded control master, and the 1442 * timeout has expired without any active client 1443 * connections, then quit. 1444 */ 1445 if (control_persist_exit_time > 0) { 1446 if (monotime() >= control_persist_exit_time) { 1447 debug("ControlPersist timeout expired"); 1448 break; 1449 } 1450 } 1451 } 1452 free(pfd); 1453 1454 /* Terminate the session. */ 1455 1456 /* Stop watching for window change. */ 1457 ssh_signal(SIGWINCH, SIG_DFL); 1458 1459 if ((r = sshpkt_start(ssh, SSH2_MSG_DISCONNECT)) != 0 || 1460 (r = sshpkt_put_u32(ssh, SSH2_DISCONNECT_BY_APPLICATION)) != 0 || 1461 (r = sshpkt_put_cstring(ssh, "disconnected by user")) != 0 || 1462 (r = sshpkt_put_cstring(ssh, "")) != 0 || /* language tag */ 1463 (r = sshpkt_send(ssh)) != 0 || 1464 (r = ssh_packet_write_wait(ssh)) != 0) 1465 fatal_fr(r, "send disconnect"); 1466 1467 channel_free_all(ssh); 1468 1469 if (have_pty) 1470 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 1471 1472 /* 1473 * If there was no shell or command requested, there will be no remote 1474 * exit status to be returned. In that case, clear error code if the 1475 * connection was deliberately terminated at this end. 1476 */ 1477 if (options.session_type == SESSION_TYPE_NONE && 1478 received_signal == SIGTERM) { 1479 received_signal = 0; 1480 exit_status = 0; 1481 } 1482 1483 if (received_signal) { 1484 verbose("Killed by signal %d.", (int) received_signal); 1485 cleanup_exit(255); 1486 } 1487 1488 /* 1489 * In interactive mode (with pseudo tty) display a message indicating 1490 * that the connection has been closed. 1491 */ 1492 if (have_pty && options.log_level >= SYSLOG_LEVEL_INFO) 1493 quit_message("Connection to %s closed.", host); 1494 1495 /* Output any buffered data for stderr. */ 1496 if (sshbuf_len(stderr_buffer) > 0) { 1497 len = atomicio(vwrite, fileno(stderr), 1498 (u_char *)sshbuf_ptr(stderr_buffer), 1499 sshbuf_len(stderr_buffer)); 1500 if (len < 0 || (u_int)len != sshbuf_len(stderr_buffer)) 1501 error("Write failed flushing stderr buffer."); 1502 else if ((r = sshbuf_consume(stderr_buffer, len)) != 0) 1503 fatal_fr(r, "sshbuf_consume"); 1504 } 1505 1506 /* Clear and free any buffers. */ 1507 sshbuf_free(stderr_buffer); 1508 1509 /* Report bytes transferred, and transfer rates. */ 1510 total_time = monotime_double() - start_time; 1511 ssh_packet_get_bytes(ssh, &ibytes, &obytes); 1512 verbose("Transferred: sent %llu, received %llu bytes, in %.1f seconds", 1513 (unsigned long long)obytes, (unsigned long long)ibytes, total_time); 1514 if (total_time > 0) 1515 verbose("Bytes per second: sent %.1f, received %.1f", 1516 obytes / total_time, ibytes / total_time); 1517 /* Return the exit status of the program. */ 1518 debug("Exit status %d", exit_status); 1519 return exit_status; 1520 } 1521 1522 /*********/ 1523 1524 static Channel * 1525 client_request_forwarded_tcpip(struct ssh *ssh, const char *request_type, 1526 int rchan, u_int rwindow, u_int rmaxpack) 1527 { 1528 Channel *c = NULL; 1529 struct sshbuf *b = NULL; 1530 char *listen_address, *originator_address; 1531 u_int listen_port, originator_port; 1532 int r; 1533 1534 /* Get rest of the packet */ 1535 if ((r = sshpkt_get_cstring(ssh, &listen_address, NULL)) != 0 || 1536 (r = sshpkt_get_u32(ssh, &listen_port)) != 0 || 1537 (r = sshpkt_get_cstring(ssh, &originator_address, NULL)) != 0 || 1538 (r = sshpkt_get_u32(ssh, &originator_port)) != 0 || 1539 (r = sshpkt_get_end(ssh)) != 0) 1540 fatal_fr(r, "parse packet"); 1541 1542 debug_f("listen %s port %d, originator %s port %d", 1543 listen_address, listen_port, originator_address, originator_port); 1544 1545 if (listen_port > 0xffff) 1546 error_f("invalid listen port"); 1547 else if (originator_port > 0xffff) 1548 error_f("invalid originator port"); 1549 else { 1550 c = channel_connect_by_listen_address(ssh, 1551 listen_address, listen_port, "forwarded-tcpip", 1552 originator_address); 1553 } 1554 1555 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) { 1556 if ((b = sshbuf_new()) == NULL) { 1557 error_f("alloc reply"); 1558 goto out; 1559 } 1560 /* reconstruct and send to muxclient */ 1561 if ((r = sshbuf_put_u8(b, 0)) != 0 || /* padlen */ 1562 (r = sshbuf_put_u8(b, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1563 (r = sshbuf_put_cstring(b, request_type)) != 0 || 1564 (r = sshbuf_put_u32(b, rchan)) != 0 || 1565 (r = sshbuf_put_u32(b, rwindow)) != 0 || 1566 (r = sshbuf_put_u32(b, rmaxpack)) != 0 || 1567 (r = sshbuf_put_cstring(b, listen_address)) != 0 || 1568 (r = sshbuf_put_u32(b, listen_port)) != 0 || 1569 (r = sshbuf_put_cstring(b, originator_address)) != 0 || 1570 (r = sshbuf_put_u32(b, originator_port)) != 0 || 1571 (r = sshbuf_put_stringb(c->output, b)) != 0) { 1572 error_fr(r, "compose for muxclient"); 1573 goto out; 1574 } 1575 } 1576 1577 out: 1578 sshbuf_free(b); 1579 free(originator_address); 1580 free(listen_address); 1581 return c; 1582 } 1583 1584 static Channel * 1585 client_request_forwarded_streamlocal(struct ssh *ssh, 1586 const char *request_type, int rchan) 1587 { 1588 Channel *c = NULL; 1589 char *listen_path; 1590 int r; 1591 1592 /* Get the remote path. */ 1593 if ((r = sshpkt_get_cstring(ssh, &listen_path, NULL)) != 0 || 1594 (r = sshpkt_get_string(ssh, NULL, NULL)) != 0 || /* reserved */ 1595 (r = sshpkt_get_end(ssh)) != 0) 1596 fatal_fr(r, "parse packet"); 1597 1598 debug_f("request: %s", listen_path); 1599 1600 c = channel_connect_by_listen_path(ssh, listen_path, 1601 "forwarded-streamlocal@openssh.com", "forwarded-streamlocal"); 1602 free(listen_path); 1603 return c; 1604 } 1605 1606 static Channel * 1607 client_request_x11(struct ssh *ssh, const char *request_type, int rchan) 1608 { 1609 Channel *c = NULL; 1610 char *originator; 1611 u_int originator_port; 1612 int r, sock; 1613 1614 if (!options.forward_x11) { 1615 error("Warning: ssh server tried X11 forwarding."); 1616 error("Warning: this is probably a break-in attempt by a " 1617 "malicious server."); 1618 return NULL; 1619 } 1620 if (x11_refuse_time != 0 && (u_int)monotime() >= x11_refuse_time) { 1621 verbose("Rejected X11 connection after ForwardX11Timeout " 1622 "expired"); 1623 return NULL; 1624 } 1625 if ((r = sshpkt_get_cstring(ssh, &originator, NULL)) != 0 || 1626 (r = sshpkt_get_u32(ssh, &originator_port)) != 0 || 1627 (r = sshpkt_get_end(ssh)) != 0) 1628 fatal_fr(r, "parse packet"); 1629 /* XXX check permission */ 1630 /* XXX range check originator port? */ 1631 debug("client_request_x11: request from %s %u", originator, 1632 originator_port); 1633 free(originator); 1634 sock = x11_connect_display(ssh); 1635 if (sock < 0) 1636 return NULL; 1637 c = channel_new(ssh, "x11", 1638 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1639 CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); 1640 c->force_drain = 1; 1641 return c; 1642 } 1643 1644 static Channel * 1645 client_request_agent(struct ssh *ssh, const char *request_type, int rchan) 1646 { 1647 Channel *c = NULL; 1648 int r, sock; 1649 1650 if (!options.forward_agent) { 1651 error("Warning: ssh server tried agent forwarding."); 1652 error("Warning: this is probably a break-in attempt by a " 1653 "malicious server."); 1654 return NULL; 1655 } 1656 if (forward_agent_sock_path == NULL) { 1657 r = ssh_get_authentication_socket(&sock); 1658 } else { 1659 r = ssh_get_authentication_socket_path(forward_agent_sock_path, &sock); 1660 } 1661 if (r != 0) { 1662 if (r != SSH_ERR_AGENT_NOT_PRESENT) 1663 debug_fr(r, "ssh_get_authentication_socket"); 1664 return NULL; 1665 } 1666 if ((r = ssh_agent_bind_hostkey(sock, ssh->kex->initial_hostkey, 1667 ssh->kex->session_id, ssh->kex->initial_sig, 1)) == 0) 1668 debug_f("bound agent to hostkey"); 1669 else 1670 debug2_fr(r, "ssh_agent_bind_hostkey"); 1671 1672 c = channel_new(ssh, "authentication agent connection", 1673 SSH_CHANNEL_OPEN, sock, sock, -1, 1674 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, 1675 "authentication agent connection", 1); 1676 c->force_drain = 1; 1677 return c; 1678 } 1679 1680 char * 1681 client_request_tun_fwd(struct ssh *ssh, int tun_mode, 1682 int local_tun, int remote_tun, channel_open_fn *cb, void *cbctx) 1683 { 1684 Channel *c; 1685 int r, fd; 1686 char *ifname = NULL; 1687 1688 if (tun_mode == SSH_TUNMODE_NO) 1689 return 0; 1690 1691 debug("Requesting tun unit %d in mode %d", local_tun, tun_mode); 1692 1693 /* Open local tunnel device */ 1694 if ((fd = tun_open(local_tun, tun_mode, &ifname)) == -1) { 1695 error("Tunnel device open failed."); 1696 return NULL; 1697 } 1698 debug("Tunnel forwarding using interface %s", ifname); 1699 1700 c = channel_new(ssh, "tun", SSH_CHANNEL_OPENING, fd, fd, -1, 1701 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1); 1702 c->datagram = 1; 1703 1704 #if defined(SSH_TUN_FILTER) 1705 if (options.tun_open == SSH_TUNMODE_POINTOPOINT) 1706 channel_register_filter(ssh, c->self, sys_tun_infilter, 1707 sys_tun_outfilter, NULL, NULL); 1708 #endif 1709 1710 if (cb != NULL) 1711 channel_register_open_confirm(ssh, c->self, cb, cbctx); 1712 1713 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN)) != 0 || 1714 (r = sshpkt_put_cstring(ssh, "tun@openssh.com")) != 0 || 1715 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1716 (r = sshpkt_put_u32(ssh, c->local_window_max)) != 0 || 1717 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 1718 (r = sshpkt_put_u32(ssh, tun_mode)) != 0 || 1719 (r = sshpkt_put_u32(ssh, remote_tun)) != 0 || 1720 (r = sshpkt_send(ssh)) != 0) 1721 sshpkt_fatal(ssh, r, "%s: send reply", __func__); 1722 1723 return ifname; 1724 } 1725 1726 /* XXXX move to generic input handler */ 1727 static int 1728 client_input_channel_open(int type, u_int32_t seq, struct ssh *ssh) 1729 { 1730 Channel *c = NULL; 1731 char *ctype = NULL; 1732 int r; 1733 u_int rchan; 1734 size_t len; 1735 u_int rmaxpack, rwindow; 1736 1737 if ((r = sshpkt_get_cstring(ssh, &ctype, &len)) != 0 || 1738 (r = sshpkt_get_u32(ssh, &rchan)) != 0 || 1739 (r = sshpkt_get_u32(ssh, &rwindow)) != 0 || 1740 (r = sshpkt_get_u32(ssh, &rmaxpack)) != 0) 1741 goto out; 1742 1743 debug("client_input_channel_open: ctype %s rchan %d win %d max %d", 1744 ctype, rchan, rwindow, rmaxpack); 1745 1746 if (strcmp(ctype, "forwarded-tcpip") == 0) { 1747 c = client_request_forwarded_tcpip(ssh, ctype, rchan, rwindow, 1748 rmaxpack); 1749 } else if (strcmp(ctype, "forwarded-streamlocal@openssh.com") == 0) { 1750 c = client_request_forwarded_streamlocal(ssh, ctype, rchan); 1751 } else if (strcmp(ctype, "x11") == 0) { 1752 c = client_request_x11(ssh, ctype, rchan); 1753 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) { 1754 c = client_request_agent(ssh, ctype, rchan); 1755 } 1756 if (c != NULL && c->type == SSH_CHANNEL_MUX_CLIENT) { 1757 debug3("proxied to downstream: %s", ctype); 1758 } else if (c != NULL) { 1759 debug("confirm %s", ctype); 1760 c->remote_id = rchan; 1761 c->have_remote_id = 1; 1762 c->remote_window = rwindow; 1763 c->remote_maxpacket = rmaxpack; 1764 if (c->type != SSH_CHANNEL_CONNECTING) { 1765 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION)) != 0 || 1766 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1767 (r = sshpkt_put_u32(ssh, c->self)) != 0 || 1768 (r = sshpkt_put_u32(ssh, c->local_window)) != 0 || 1769 (r = sshpkt_put_u32(ssh, c->local_maxpacket)) != 0 || 1770 (r = sshpkt_send(ssh)) != 0) 1771 sshpkt_fatal(ssh, r, "%s: send reply", __func__); 1772 } 1773 } else { 1774 debug("failure %s", ctype); 1775 if ((r = sshpkt_start(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE)) != 0 || 1776 (r = sshpkt_put_u32(ssh, rchan)) != 0 || 1777 (r = sshpkt_put_u32(ssh, SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED)) != 0 || 1778 (r = sshpkt_put_cstring(ssh, "open failed")) != 0 || 1779 (r = sshpkt_put_cstring(ssh, "")) != 0 || 1780 (r = sshpkt_send(ssh)) != 0) 1781 sshpkt_fatal(ssh, r, "%s: send failure", __func__); 1782 } 1783 r = 0; 1784 out: 1785 free(ctype); 1786 return r; 1787 } 1788 1789 static int 1790 client_input_channel_req(int type, u_int32_t seq, struct ssh *ssh) 1791 { 1792 Channel *c = NULL; 1793 char *rtype = NULL; 1794 u_char reply; 1795 u_int id, exitval; 1796 int r, success = 0; 1797 1798 if ((r = sshpkt_get_u32(ssh, &id)) != 0) 1799 return r; 1800 if (id <= INT_MAX) 1801 c = channel_lookup(ssh, id); 1802 if (channel_proxy_upstream(c, type, seq, ssh)) 1803 return 0; 1804 if ((r = sshpkt_get_cstring(ssh, &rtype, NULL)) != 0 || 1805 (r = sshpkt_get_u8(ssh, &reply)) != 0) 1806 goto out; 1807 1808 debug("client_input_channel_req: channel %u rtype %s reply %d", 1809 id, rtype, reply); 1810 1811 if (c == NULL) { 1812 error("client_input_channel_req: channel %d: " 1813 "unknown channel", id); 1814 } else if (strcmp(rtype, "eow@openssh.com") == 0) { 1815 if ((r = sshpkt_get_end(ssh)) != 0) 1816 goto out; 1817 chan_rcvd_eow(ssh, c); 1818 } else if (strcmp(rtype, "exit-status") == 0) { 1819 if ((r = sshpkt_get_u32(ssh, &exitval)) != 0) 1820 goto out; 1821 if (c->ctl_chan != -1) { 1822 mux_exit_message(ssh, c, exitval); 1823 success = 1; 1824 } else if ((int)id == session_ident) { 1825 /* Record exit value of local session */ 1826 success = 1; 1827 exit_status = exitval; 1828 } else { 1829 /* Probably for a mux channel that has already closed */ 1830 debug_f("no sink for exit-status on channel %d", 1831 id); 1832 } 1833 if ((r = sshpkt_get_end(ssh)) != 0) 1834 goto out; 1835 } 1836 if (reply && c != NULL && !(c->flags & CHAN_CLOSE_SENT)) { 1837 if (!c->have_remote_id) 1838 fatal_f("channel %d: no remote_id", c->self); 1839 if ((r = sshpkt_start(ssh, success ? 1840 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE)) != 0 || 1841 (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 || 1842 (r = sshpkt_send(ssh)) != 0) 1843 sshpkt_fatal(ssh, r, "%s: send failure", __func__); 1844 } 1845 r = 0; 1846 out: 1847 free(rtype); 1848 return r; 1849 } 1850 1851 struct hostkeys_update_ctx { 1852 /* The hostname and (optionally) IP address string for the server */ 1853 char *host_str, *ip_str; 1854 1855 /* 1856 * Keys received from the server and a flag for each indicating 1857 * whether they already exist in known_hosts. 1858 * keys_match is filled in by hostkeys_find() and later (for new 1859 * keys) by client_global_hostkeys_prove_confirm(). 1860 */ 1861 struct sshkey **keys; 1862 u_int *keys_match; /* mask of HKF_MATCH_* from hostfile.h */ 1863 int *keys_verified; /* flag for new keys verified by server */ 1864 size_t nkeys, nnew, nincomplete; /* total, new keys, incomplete match */ 1865 1866 /* 1867 * Keys that are in known_hosts, but were not present in the update 1868 * from the server (i.e. scheduled to be deleted). 1869 * Filled in by hostkeys_find(). 1870 */ 1871 struct sshkey **old_keys; 1872 size_t nold; 1873 1874 /* Various special cases. */ 1875 int complex_hostspec; /* wildcard or manual pattern-list host name */ 1876 int ca_available; /* saw CA key for this host */ 1877 int old_key_seen; /* saw old key with other name/addr */ 1878 int other_name_seen; /* saw key with other name/addr */ 1879 }; 1880 1881 static void 1882 hostkeys_update_ctx_free(struct hostkeys_update_ctx *ctx) 1883 { 1884 size_t i; 1885 1886 if (ctx == NULL) 1887 return; 1888 for (i = 0; i < ctx->nkeys; i++) 1889 sshkey_free(ctx->keys[i]); 1890 free(ctx->keys); 1891 free(ctx->keys_match); 1892 free(ctx->keys_verified); 1893 for (i = 0; i < ctx->nold; i++) 1894 sshkey_free(ctx->old_keys[i]); 1895 free(ctx->old_keys); 1896 free(ctx->host_str); 1897 free(ctx->ip_str); 1898 free(ctx); 1899 } 1900 1901 /* 1902 * Returns non-zero if a known_hosts hostname list is not of a form that 1903 * can be handled by UpdateHostkeys. These include wildcard hostnames and 1904 * hostnames lists that do not follow the form host[,ip]. 1905 */ 1906 static int 1907 hostspec_is_complex(const char *hosts) 1908 { 1909 char *cp; 1910 1911 /* wildcard */ 1912 if (strchr(hosts, '*') != NULL || strchr(hosts, '?') != NULL) 1913 return 1; 1914 /* single host/ip = ok */ 1915 if ((cp = strchr(hosts, ',')) == NULL) 1916 return 0; 1917 /* more than two entries on the line */ 1918 if (strchr(cp + 1, ',') != NULL) 1919 return 1; 1920 /* XXX maybe parse cp+1 and ensure it is an IP? */ 1921 return 0; 1922 } 1923 1924 /* callback to search for ctx->keys in known_hosts */ 1925 static int 1926 hostkeys_find(struct hostkey_foreach_line *l, void *_ctx) 1927 { 1928 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 1929 size_t i; 1930 struct sshkey **tmp; 1931 1932 if (l->key == NULL) 1933 return 0; 1934 if (l->status != HKF_STATUS_MATCHED) { 1935 /* Record if one of the keys appears on a non-matching line */ 1936 for (i = 0; i < ctx->nkeys; i++) { 1937 if (sshkey_equal(l->key, ctx->keys[i])) { 1938 ctx->other_name_seen = 1; 1939 debug3_f("found %s key under different " 1940 "name/addr at %s:%ld", 1941 sshkey_ssh_name(ctx->keys[i]), 1942 l->path, l->linenum); 1943 return 0; 1944 } 1945 } 1946 return 0; 1947 } 1948 /* Don't proceed if revocation or CA markers are present */ 1949 /* XXX relax this */ 1950 if (l->marker != MRK_NONE) { 1951 debug3_f("hostkeys file %s:%ld has CA/revocation marker", 1952 l->path, l->linenum); 1953 ctx->complex_hostspec = 1; 1954 return 0; 1955 } 1956 1957 /* If CheckHostIP is enabled, then check for mismatched hostname/addr */ 1958 if (ctx->ip_str != NULL && strchr(l->hosts, ',') != NULL) { 1959 if ((l->match & HKF_MATCH_HOST) == 0) { 1960 /* Record if address matched a different hostname. */ 1961 ctx->other_name_seen = 1; 1962 debug3_f("found address %s against different hostname " 1963 "at %s:%ld", ctx->ip_str, l->path, l->linenum); 1964 return 0; 1965 } else if ((l->match & HKF_MATCH_IP) == 0) { 1966 /* Record if hostname matched a different address. */ 1967 ctx->other_name_seen = 1; 1968 debug3_f("found hostname %s against different address " 1969 "at %s:%ld", ctx->host_str, l->path, l->linenum); 1970 } 1971 } 1972 1973 /* 1974 * UpdateHostkeys is skipped for wildcard host names and hostnames 1975 * that contain more than two entries (ssh never writes these). 1976 */ 1977 if (hostspec_is_complex(l->hosts)) { 1978 debug3_f("hostkeys file %s:%ld complex host specification", 1979 l->path, l->linenum); 1980 ctx->complex_hostspec = 1; 1981 return 0; 1982 } 1983 1984 /* Mark off keys we've already seen for this host */ 1985 for (i = 0; i < ctx->nkeys; i++) { 1986 if (!sshkey_equal(l->key, ctx->keys[i])) 1987 continue; 1988 debug3_f("found %s key at %s:%ld", 1989 sshkey_ssh_name(ctx->keys[i]), l->path, l->linenum); 1990 ctx->keys_match[i] |= l->match; 1991 return 0; 1992 } 1993 /* This line contained a key that not offered by the server */ 1994 debug3_f("deprecated %s key at %s:%ld", sshkey_ssh_name(l->key), 1995 l->path, l->linenum); 1996 if ((tmp = recallocarray(ctx->old_keys, ctx->nold, ctx->nold + 1, 1997 sizeof(*ctx->old_keys))) == NULL) 1998 fatal_f("recallocarray failed nold = %zu", ctx->nold); 1999 ctx->old_keys = tmp; 2000 ctx->old_keys[ctx->nold++] = l->key; 2001 l->key = NULL; 2002 2003 return 0; 2004 } 2005 2006 /* callback to search for ctx->old_keys in known_hosts under other names */ 2007 static int 2008 hostkeys_check_old(struct hostkey_foreach_line *l, void *_ctx) 2009 { 2010 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 2011 size_t i; 2012 int hashed; 2013 2014 /* only care about lines that *don't* match the active host spec */ 2015 if (l->status == HKF_STATUS_MATCHED || l->key == NULL) 2016 return 0; 2017 2018 hashed = l->match & (HKF_MATCH_HOST_HASHED|HKF_MATCH_IP_HASHED); 2019 for (i = 0; i < ctx->nold; i++) { 2020 if (!sshkey_equal(l->key, ctx->old_keys[i])) 2021 continue; 2022 debug3_f("found deprecated %s key at %s:%ld as %s", 2023 sshkey_ssh_name(ctx->old_keys[i]), l->path, l->linenum, 2024 hashed ? "[HASHED]" : l->hosts); 2025 ctx->old_key_seen = 1; 2026 break; 2027 } 2028 return 0; 2029 } 2030 2031 /* 2032 * Check known_hosts files for deprecated keys under other names. Returns 0 2033 * on success or -1 on failure. Updates ctx->old_key_seen if deprecated keys 2034 * exist under names other than the active hostname/IP. 2035 */ 2036 static int 2037 check_old_keys_othernames(struct hostkeys_update_ctx *ctx) 2038 { 2039 size_t i; 2040 int r; 2041 2042 debug2_f("checking for %zu deprecated keys", ctx->nold); 2043 for (i = 0; i < options.num_user_hostfiles; i++) { 2044 debug3_f("searching %s for %s / %s", 2045 options.user_hostfiles[i], ctx->host_str, 2046 ctx->ip_str ? ctx->ip_str : "(none)"); 2047 if ((r = hostkeys_foreach(options.user_hostfiles[i], 2048 hostkeys_check_old, ctx, ctx->host_str, ctx->ip_str, 2049 HKF_WANT_PARSE_KEY, 0)) != 0) { 2050 if (r == SSH_ERR_SYSTEM_ERROR && errno == ENOENT) { 2051 debug_f("hostkeys file %s does not exist", 2052 options.user_hostfiles[i]); 2053 continue; 2054 } 2055 error_fr(r, "hostkeys_foreach failed for %s", 2056 options.user_hostfiles[i]); 2057 return -1; 2058 } 2059 } 2060 return 0; 2061 } 2062 2063 static void 2064 hostkey_change_preamble(LogLevel loglevel) 2065 { 2066 do_log2(loglevel, "The server has updated its host keys."); 2067 do_log2(loglevel, "These changes were verified by the server's " 2068 "existing trusted key."); 2069 } 2070 2071 static void 2072 update_known_hosts(struct hostkeys_update_ctx *ctx) 2073 { 2074 int r, was_raw = 0, first = 1; 2075 int asking = options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK; 2076 LogLevel loglevel = asking ? SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_VERBOSE; 2077 char *fp, *response; 2078 size_t i; 2079 struct stat sb; 2080 2081 for (i = 0; i < ctx->nkeys; i++) { 2082 if (!ctx->keys_verified[i]) 2083 continue; 2084 if ((fp = sshkey_fingerprint(ctx->keys[i], 2085 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 2086 fatal_f("sshkey_fingerprint failed"); 2087 if (first && asking) 2088 hostkey_change_preamble(loglevel); 2089 do_log2(loglevel, "Learned new hostkey: %s %s", 2090 sshkey_type(ctx->keys[i]), fp); 2091 first = 0; 2092 free(fp); 2093 } 2094 for (i = 0; i < ctx->nold; i++) { 2095 if ((fp = sshkey_fingerprint(ctx->old_keys[i], 2096 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 2097 fatal_f("sshkey_fingerprint failed"); 2098 if (first && asking) 2099 hostkey_change_preamble(loglevel); 2100 do_log2(loglevel, "Deprecating obsolete hostkey: %s %s", 2101 sshkey_type(ctx->old_keys[i]), fp); 2102 first = 0; 2103 free(fp); 2104 } 2105 if (options.update_hostkeys == SSH_UPDATE_HOSTKEYS_ASK) { 2106 if (get_saved_tio() != NULL) { 2107 leave_raw_mode(1); 2108 was_raw = 1; 2109 } 2110 response = NULL; 2111 for (i = 0; !quit_pending && i < 3; i++) { 2112 free(response); 2113 response = read_passphrase("Accept updated hostkeys? " 2114 "(yes/no): ", RP_ECHO); 2115 if (strcasecmp(response, "yes") == 0) 2116 break; 2117 else if (quit_pending || response == NULL || 2118 strcasecmp(response, "no") == 0) { 2119 options.update_hostkeys = 0; 2120 break; 2121 } else { 2122 do_log2(loglevel, "Please enter " 2123 "\"yes\" or \"no\""); 2124 } 2125 } 2126 if (quit_pending || i >= 3 || response == NULL) 2127 options.update_hostkeys = 0; 2128 free(response); 2129 if (was_raw) 2130 enter_raw_mode(1); 2131 } 2132 if (options.update_hostkeys == 0) 2133 return; 2134 /* 2135 * Now that all the keys are verified, we can go ahead and replace 2136 * them in known_hosts (assuming SSH_UPDATE_HOSTKEYS_ASK didn't 2137 * cancel the operation). 2138 */ 2139 for (i = 0; i < options.num_user_hostfiles; i++) { 2140 /* 2141 * NB. keys are only added to hostfiles[0], for the rest we 2142 * just delete the hostname entries. 2143 */ 2144 if (stat(options.user_hostfiles[i], &sb) != 0) { 2145 if (errno == ENOENT) { 2146 debug_f("known hosts file %s does not " 2147 "exist", options.user_hostfiles[i]); 2148 } else { 2149 error_f("known hosts file %s " 2150 "inaccessible: %s", 2151 options.user_hostfiles[i], strerror(errno)); 2152 } 2153 continue; 2154 } 2155 if ((r = hostfile_replace_entries(options.user_hostfiles[i], 2156 ctx->host_str, ctx->ip_str, 2157 i == 0 ? ctx->keys : NULL, i == 0 ? ctx->nkeys : 0, 2158 options.hash_known_hosts, 0, 2159 options.fingerprint_hash)) != 0) { 2160 error_fr(r, "hostfile_replace_entries failed for %s", 2161 options.user_hostfiles[i]); 2162 } 2163 } 2164 } 2165 2166 static void 2167 client_global_hostkeys_prove_confirm(struct ssh *ssh, int type, 2168 u_int32_t seq, void *_ctx) 2169 { 2170 struct hostkeys_update_ctx *ctx = (struct hostkeys_update_ctx *)_ctx; 2171 size_t i, ndone; 2172 struct sshbuf *signdata; 2173 int r, plaintype; 2174 const u_char *sig; 2175 const char *rsa_kexalg = NULL; 2176 char *alg = NULL; 2177 size_t siglen; 2178 2179 if (ctx->nnew == 0) 2180 fatal_f("ctx->nnew == 0"); /* sanity */ 2181 if (type != SSH2_MSG_REQUEST_SUCCESS) { 2182 error("Server failed to confirm ownership of " 2183 "private host keys"); 2184 hostkeys_update_ctx_free(ctx); 2185 return; 2186 } 2187 if (sshkey_type_plain(sshkey_type_from_name( 2188 ssh->kex->hostkey_alg)) == KEY_RSA) 2189 rsa_kexalg = ssh->kex->hostkey_alg; 2190 if ((signdata = sshbuf_new()) == NULL) 2191 fatal_f("sshbuf_new failed"); 2192 /* 2193 * Expect a signature for each of the ctx->nnew private keys we 2194 * haven't seen before. They will be in the same order as the 2195 * ctx->keys where the corresponding ctx->keys_match[i] == 0. 2196 */ 2197 for (ndone = i = 0; i < ctx->nkeys; i++) { 2198 if (ctx->keys_match[i]) 2199 continue; 2200 plaintype = sshkey_type_plain(ctx->keys[i]->type); 2201 /* Prepare data to be signed: session ID, unique string, key */ 2202 sshbuf_reset(signdata); 2203 if ( (r = sshbuf_put_cstring(signdata, 2204 "hostkeys-prove-00@openssh.com")) != 0 || 2205 (r = sshbuf_put_stringb(signdata, 2206 ssh->kex->session_id)) != 0 || 2207 (r = sshkey_puts(ctx->keys[i], signdata)) != 0) 2208 fatal_fr(r, "compose signdata"); 2209 /* Extract and verify signature */ 2210 if ((r = sshpkt_get_string_direct(ssh, &sig, &siglen)) != 0) { 2211 error_fr(r, "parse sig"); 2212 goto out; 2213 } 2214 if ((r = sshkey_get_sigtype(sig, siglen, &alg)) != 0) { 2215 error_fr(r, "server gave unintelligible signature " 2216 "for %s key %zu", sshkey_type(ctx->keys[i]), i); 2217 goto out; 2218 } 2219 /* 2220 * Special case for RSA keys: if a RSA hostkey was negotiated, 2221 * then use its signature type for verification of RSA hostkey 2222 * proofs. Otherwise, accept only RSA-SHA256/512 signatures. 2223 */ 2224 if (plaintype == KEY_RSA && rsa_kexalg == NULL && 2225 match_pattern_list(alg, HOSTKEY_PROOF_RSA_ALGS, 0) != 1) { 2226 debug_f("server used untrusted RSA signature algorithm " 2227 "%s for key %zu, disregarding", alg, i); 2228 free(alg); 2229 /* zap the key from the list */ 2230 sshkey_free(ctx->keys[i]); 2231 ctx->keys[i] = NULL; 2232 ndone++; 2233 continue; 2234 } 2235 debug3_f("verify %s key %zu using sigalg %s", 2236 sshkey_type(ctx->keys[i]), i, alg); 2237 free(alg); 2238 if ((r = sshkey_verify(ctx->keys[i], sig, siglen, 2239 sshbuf_ptr(signdata), sshbuf_len(signdata), 2240 plaintype == KEY_RSA ? rsa_kexalg : NULL, 0, NULL)) != 0) { 2241 error_fr(r, "server gave bad signature for %s key %zu", 2242 sshkey_type(ctx->keys[i]), i); 2243 goto out; 2244 } 2245 /* Key is good. Mark it as 'seen' */ 2246 ctx->keys_verified[i] = 1; 2247 ndone++; 2248 } 2249 /* Shouldn't happen */ 2250 if (ndone != ctx->nnew) 2251 fatal_f("ndone != ctx->nnew (%zu / %zu)", ndone, ctx->nnew); 2252 if ((r = sshpkt_get_end(ssh)) != 0) { 2253 error_f("protocol error"); 2254 goto out; 2255 } 2256 2257 /* Make the edits to known_hosts */ 2258 update_known_hosts(ctx); 2259 out: 2260 hostkeys_update_ctx_free(ctx); 2261 hostkeys_update_complete = 1; 2262 client_repledge(); 2263 } 2264 2265 /* 2266 * Returns non-zero if the key is accepted by HostkeyAlgorithms. 2267 * Made slightly less trivial by the multiple RSA signature algorithm names. 2268 */ 2269 static int 2270 key_accepted_by_hostkeyalgs(const struct sshkey *key) 2271 { 2272 const char *ktype = sshkey_ssh_name(key); 2273 const char *hostkeyalgs = options.hostkeyalgorithms; 2274 2275 if (key == NULL || key->type == KEY_UNSPEC) 2276 return 0; 2277 if (key->type == KEY_RSA && 2278 (match_pattern_list("rsa-sha2-256", hostkeyalgs, 0) == 1 || 2279 match_pattern_list("rsa-sha2-512", hostkeyalgs, 0) == 1)) 2280 return 1; 2281 return match_pattern_list(ktype, hostkeyalgs, 0) == 1; 2282 } 2283 2284 /* 2285 * Handle hostkeys-00@openssh.com global request to inform the client of all 2286 * the server's hostkeys. The keys are checked against the user's 2287 * HostkeyAlgorithms preference before they are accepted. 2288 */ 2289 static int 2290 client_input_hostkeys(struct ssh *ssh) 2291 { 2292 const u_char *blob = NULL; 2293 size_t i, len = 0; 2294 struct sshbuf *buf = NULL; 2295 struct sshkey *key = NULL, **tmp; 2296 int r, prove_sent = 0; 2297 char *fp; 2298 static int hostkeys_seen = 0; /* XXX use struct ssh */ 2299 extern struct sockaddr_storage hostaddr; /* XXX from ssh.c */ 2300 struct hostkeys_update_ctx *ctx = NULL; 2301 u_int want; 2302 2303 if (hostkeys_seen) 2304 fatal_f("server already sent hostkeys"); 2305 if (!can_update_hostkeys()) 2306 return 1; 2307 hostkeys_seen = 1; 2308 2309 ctx = xcalloc(1, sizeof(*ctx)); 2310 while (ssh_packet_remaining(ssh) > 0) { 2311 sshkey_free(key); 2312 key = NULL; 2313 if ((r = sshpkt_get_string_direct(ssh, &blob, &len)) != 0) { 2314 error_fr(r, "parse key"); 2315 goto out; 2316 } 2317 if ((r = sshkey_from_blob(blob, len, &key)) != 0) { 2318 do_log2_fr(r, r == SSH_ERR_KEY_TYPE_UNKNOWN ? 2319 SYSLOG_LEVEL_DEBUG1 : SYSLOG_LEVEL_ERROR, 2320 "convert key"); 2321 continue; 2322 } 2323 fp = sshkey_fingerprint(key, options.fingerprint_hash, 2324 SSH_FP_DEFAULT); 2325 debug3_f("received %s key %s", sshkey_type(key), fp); 2326 free(fp); 2327 2328 if (!key_accepted_by_hostkeyalgs(key)) { 2329 debug3_f("%s key not permitted by " 2330 "HostkeyAlgorithms", sshkey_ssh_name(key)); 2331 continue; 2332 } 2333 /* Skip certs */ 2334 if (sshkey_is_cert(key)) { 2335 debug3_f("%s key is a certificate; skipping", 2336 sshkey_ssh_name(key)); 2337 continue; 2338 } 2339 /* Ensure keys are unique */ 2340 for (i = 0; i < ctx->nkeys; i++) { 2341 if (sshkey_equal(key, ctx->keys[i])) { 2342 error_f("received duplicated %s host key", 2343 sshkey_ssh_name(key)); 2344 goto out; 2345 } 2346 } 2347 /* Key is good, record it */ 2348 if ((tmp = recallocarray(ctx->keys, ctx->nkeys, ctx->nkeys + 1, 2349 sizeof(*ctx->keys))) == NULL) 2350 fatal_f("recallocarray failed nkeys = %zu", 2351 ctx->nkeys); 2352 ctx->keys = tmp; 2353 ctx->keys[ctx->nkeys++] = key; 2354 key = NULL; 2355 } 2356 2357 if (ctx->nkeys == 0) { 2358 debug_f("server sent no hostkeys"); 2359 goto out; 2360 } 2361 2362 if ((ctx->keys_match = calloc(ctx->nkeys, 2363 sizeof(*ctx->keys_match))) == NULL || 2364 (ctx->keys_verified = calloc(ctx->nkeys, 2365 sizeof(*ctx->keys_verified))) == NULL) 2366 fatal_f("calloc failed"); 2367 2368 get_hostfile_hostname_ipaddr(host, 2369 options.check_host_ip ? (struct sockaddr *)&hostaddr : NULL, 2370 options.port, &ctx->host_str, 2371 options.check_host_ip ? &ctx->ip_str : NULL); 2372 2373 /* Find which keys we already know about. */ 2374 for (i = 0; i < options.num_user_hostfiles; i++) { 2375 debug_f("searching %s for %s / %s", 2376 options.user_hostfiles[i], ctx->host_str, 2377 ctx->ip_str ? ctx->ip_str : "(none)"); 2378 if ((r = hostkeys_foreach(options.user_hostfiles[i], 2379 hostkeys_find, ctx, ctx->host_str, ctx->ip_str, 2380 HKF_WANT_PARSE_KEY, 0)) != 0) { 2381 if (r == SSH_ERR_SYSTEM_ERROR && errno == ENOENT) { 2382 debug_f("hostkeys file %s does not exist", 2383 options.user_hostfiles[i]); 2384 continue; 2385 } 2386 error_fr(r, "hostkeys_foreach failed for %s", 2387 options.user_hostfiles[i]); 2388 goto out; 2389 } 2390 } 2391 2392 /* Figure out if we have any new keys to add */ 2393 ctx->nnew = ctx->nincomplete = 0; 2394 want = HKF_MATCH_HOST | ( options.check_host_ip ? HKF_MATCH_IP : 0); 2395 for (i = 0; i < ctx->nkeys; i++) { 2396 if (ctx->keys_match[i] == 0) 2397 ctx->nnew++; 2398 if ((ctx->keys_match[i] & want) != want) 2399 ctx->nincomplete++; 2400 } 2401 2402 debug3_f("%zu server keys: %zu new, %zu retained, " 2403 "%zu incomplete match. %zu to remove", ctx->nkeys, ctx->nnew, 2404 ctx->nkeys - ctx->nnew - ctx->nincomplete, 2405 ctx->nincomplete, ctx->nold); 2406 2407 if (ctx->nnew == 0 && ctx->nold == 0) { 2408 debug_f("no new or deprecated keys from server"); 2409 goto out; 2410 } 2411 2412 /* Various reasons why we cannot proceed with the update */ 2413 if (ctx->complex_hostspec) { 2414 debug_f("CA/revocation marker, manual host list or wildcard " 2415 "host pattern found, skipping UserKnownHostsFile update"); 2416 goto out; 2417 } 2418 if (ctx->other_name_seen) { 2419 debug_f("host key found matching a different name/address, " 2420 "skipping UserKnownHostsFile update"); 2421 goto out; 2422 } 2423 /* 2424 * If removing keys, check whether they appear under different 2425 * names/addresses and refuse to proceed if they do. This avoids 2426 * cases such as hosts with multiple names becoming inconsistent 2427 * with regards to CheckHostIP entries. 2428 * XXX UpdateHostkeys=force to override this (and other) checks? 2429 */ 2430 if (ctx->nold != 0) { 2431 if (check_old_keys_othernames(ctx) != 0) 2432 goto out; /* error already logged */ 2433 if (ctx->old_key_seen) { 2434 debug_f("key(s) for %s%s%s exist under other names; " 2435 "skipping UserKnownHostsFile update", 2436 ctx->host_str, ctx->ip_str == NULL ? "" : ",", 2437 ctx->ip_str == NULL ? "" : ctx->ip_str); 2438 goto out; 2439 } 2440 } 2441 2442 if (ctx->nnew == 0) { 2443 /* 2444 * We have some keys to remove or fix matching for. 2445 * We can proceed to do this without requiring a fresh proof 2446 * from the server. 2447 */ 2448 update_known_hosts(ctx); 2449 goto out; 2450 } 2451 /* 2452 * We have received previously-unseen keys from the server. 2453 * Ask the server to confirm ownership of the private halves. 2454 */ 2455 debug3_f("asking server to prove ownership for %zu keys", ctx->nnew); 2456 if ((r = sshpkt_start(ssh, SSH2_MSG_GLOBAL_REQUEST)) != 0 || 2457 (r = sshpkt_put_cstring(ssh, 2458 "hostkeys-prove-00@openssh.com")) != 0 || 2459 (r = sshpkt_put_u8(ssh, 1)) != 0) /* bool: want reply */ 2460 fatal_fr(r, "prepare hostkeys-prove"); 2461 if ((buf = sshbuf_new()) == NULL) 2462 fatal_f("sshbuf_new"); 2463 for (i = 0; i < ctx->nkeys; i++) { 2464 if (ctx->keys_match[i]) 2465 continue; 2466 sshbuf_reset(buf); 2467 if ((r = sshkey_putb(ctx->keys[i], buf)) != 0 || 2468 (r = sshpkt_put_stringb(ssh, buf)) != 0) 2469 fatal_fr(r, "assemble hostkeys-prove"); 2470 } 2471 if ((r = sshpkt_send(ssh)) != 0) 2472 fatal_fr(r, "send hostkeys-prove"); 2473 client_register_global_confirm( 2474 client_global_hostkeys_prove_confirm, ctx); 2475 ctx = NULL; /* will be freed in callback */ 2476 prove_sent = 1; 2477 2478 /* Success */ 2479 out: 2480 hostkeys_update_ctx_free(ctx); 2481 sshkey_free(key); 2482 sshbuf_free(buf); 2483 if (!prove_sent) { 2484 /* UpdateHostkeys handling completed */ 2485 hostkeys_update_complete = 1; 2486 client_repledge(); 2487 } 2488 /* 2489 * NB. Return success for all cases. The server doesn't need to know 2490 * what the client does with its hosts file. 2491 */ 2492 return 1; 2493 } 2494 2495 static int 2496 client_input_global_request(int type, u_int32_t seq, struct ssh *ssh) 2497 { 2498 char *rtype; 2499 u_char want_reply; 2500 int r, success = 0; 2501 2502 if ((r = sshpkt_get_cstring(ssh, &rtype, NULL)) != 0 || 2503 (r = sshpkt_get_u8(ssh, &want_reply)) != 0) 2504 goto out; 2505 debug("client_input_global_request: rtype %s want_reply %d", 2506 rtype, want_reply); 2507 if (strcmp(rtype, "hostkeys-00@openssh.com") == 0) 2508 success = client_input_hostkeys(ssh); 2509 if (want_reply) { 2510 if ((r = sshpkt_start(ssh, success ? SSH2_MSG_REQUEST_SUCCESS : 2511 SSH2_MSG_REQUEST_FAILURE)) != 0 || 2512 (r = sshpkt_send(ssh)) != 0 || 2513 (r = ssh_packet_write_wait(ssh)) != 0) 2514 goto out; 2515 } 2516 r = 0; 2517 out: 2518 free(rtype); 2519 return r; 2520 } 2521 2522 static void 2523 client_send_env(struct ssh *ssh, int id, const char *name, const char *val) 2524 { 2525 int r; 2526 2527 debug("channel %d: setting env %s = \"%s\"", id, name, val); 2528 channel_request_start(ssh, id, "env", 0); 2529 if ((r = sshpkt_put_cstring(ssh, name)) != 0 || 2530 (r = sshpkt_put_cstring(ssh, val)) != 0 || 2531 (r = sshpkt_send(ssh)) != 0) 2532 fatal_fr(r, "send setenv"); 2533 } 2534 2535 void 2536 client_session2_setup(struct ssh *ssh, int id, int want_tty, int want_subsystem, 2537 const char *term, struct termios *tiop, int in_fd, struct sshbuf *cmd, 2538 char **env) 2539 { 2540 size_t i, j, len; 2541 int matched, r; 2542 char *name, *val; 2543 Channel *c = NULL; 2544 2545 debug2_f("id %d", id); 2546 2547 if ((c = channel_lookup(ssh, id)) == NULL) 2548 fatal_f("channel %d: unknown channel", id); 2549 2550 ssh_packet_set_interactive(ssh, want_tty, 2551 options.ip_qos_interactive, options.ip_qos_bulk); 2552 2553 if (want_tty) { 2554 struct winsize ws; 2555 2556 /* Store window size in the packet. */ 2557 if (ioctl(in_fd, TIOCGWINSZ, &ws) == -1) 2558 memset(&ws, 0, sizeof(ws)); 2559 2560 channel_request_start(ssh, id, "pty-req", 1); 2561 client_expect_confirm(ssh, id, "PTY allocation", CONFIRM_TTY); 2562 if ((r = sshpkt_put_cstring(ssh, term != NULL ? term : "")) 2563 != 0 || 2564 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_col)) != 0 || 2565 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_row)) != 0 || 2566 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_xpixel)) != 0 || 2567 (r = sshpkt_put_u32(ssh, (u_int)ws.ws_ypixel)) != 0) 2568 fatal_fr(r, "build pty-req"); 2569 if (tiop == NULL) 2570 tiop = get_saved_tio(); 2571 ssh_tty_make_modes(ssh, -1, tiop); 2572 if ((r = sshpkt_send(ssh)) != 0) 2573 fatal_fr(r, "send pty-req"); 2574 /* XXX wait for reply */ 2575 c->client_tty = 1; 2576 } 2577 2578 /* Transfer any environment variables from client to server */ 2579 if (options.num_send_env != 0 && env != NULL) { 2580 debug("Sending environment."); 2581 for (i = 0; env[i] != NULL; i++) { 2582 /* Split */ 2583 name = xstrdup(env[i]); 2584 if ((val = strchr(name, '=')) == NULL) { 2585 free(name); 2586 continue; 2587 } 2588 *val++ = '\0'; 2589 2590 matched = 0; 2591 for (j = 0; j < options.num_send_env; j++) { 2592 if (match_pattern(name, options.send_env[j])) { 2593 matched = 1; 2594 break; 2595 } 2596 } 2597 if (!matched) { 2598 debug3("Ignored env %s", name); 2599 free(name); 2600 continue; 2601 } 2602 client_send_env(ssh, id, name, val); 2603 free(name); 2604 } 2605 } 2606 for (i = 0; i < options.num_setenv; i++) { 2607 /* Split */ 2608 name = xstrdup(options.setenv[i]); 2609 if ((val = strchr(name, '=')) == NULL) { 2610 free(name); 2611 continue; 2612 } 2613 *val++ = '\0'; 2614 client_send_env(ssh, id, name, val); 2615 free(name); 2616 } 2617 2618 len = sshbuf_len(cmd); 2619 if (len > 0) { 2620 if (len > 900) 2621 len = 900; 2622 if (want_subsystem) { 2623 debug("Sending subsystem: %.*s", 2624 (int)len, (const u_char*)sshbuf_ptr(cmd)); 2625 channel_request_start(ssh, id, "subsystem", 1); 2626 client_expect_confirm(ssh, id, "subsystem", 2627 CONFIRM_CLOSE); 2628 } else { 2629 debug("Sending command: %.*s", 2630 (int)len, (const u_char*)sshbuf_ptr(cmd)); 2631 channel_request_start(ssh, id, "exec", 1); 2632 client_expect_confirm(ssh, id, "exec", CONFIRM_CLOSE); 2633 } 2634 if ((r = sshpkt_put_stringb(ssh, cmd)) != 0 || 2635 (r = sshpkt_send(ssh)) != 0) 2636 fatal_fr(r, "send command"); 2637 } else { 2638 channel_request_start(ssh, id, "shell", 1); 2639 client_expect_confirm(ssh, id, "shell", CONFIRM_CLOSE); 2640 if ((r = sshpkt_send(ssh)) != 0) 2641 fatal_fr(r, "send shell"); 2642 } 2643 2644 session_setup_complete = 1; 2645 client_repledge(); 2646 } 2647 2648 static void 2649 client_init_dispatch(struct ssh *ssh) 2650 { 2651 ssh_dispatch_init(ssh, &dispatch_protocol_error); 2652 2653 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); 2654 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_DATA, &channel_input_data); 2655 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); 2656 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); 2657 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open); 2658 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 2659 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 2660 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req); 2661 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); 2662 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm); 2663 ssh_dispatch_set(ssh, SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm); 2664 ssh_dispatch_set(ssh, SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request); 2665 2666 /* rekeying */ 2667 ssh_dispatch_set(ssh, SSH2_MSG_KEXINIT, &kex_input_kexinit); 2668 2669 /* global request reply messages */ 2670 ssh_dispatch_set(ssh, SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply); 2671 ssh_dispatch_set(ssh, SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply); 2672 } 2673 2674 void 2675 client_stop_mux(void) 2676 { 2677 if (options.control_path != NULL && muxserver_sock != -1) 2678 unlink(options.control_path); 2679 /* 2680 * If we are in persist mode, or don't have a shell, signal that we 2681 * should close when all active channels are closed. 2682 */ 2683 if (options.control_persist || options.session_type == SESSION_TYPE_NONE) { 2684 session_closed = 1; 2685 setproctitle("[stopped mux]"); 2686 } 2687 } 2688 2689 /* client specific fatal cleanup */ 2690 void 2691 cleanup_exit(int i) 2692 { 2693 leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE); 2694 if (options.control_path != NULL && muxserver_sock != -1) 2695 unlink(options.control_path); 2696 ssh_kill_proxy_command(); 2697 _exit(i); 2698 } 2699