1 /* $OpenBSD: clientloop.c,v 1.201 2008/07/16 11:51:14 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 #include <sys/param.h> 67 #ifdef HAVE_SYS_STAT_H 68 # include <sys/stat.h> 69 #endif 70 #ifdef HAVE_SYS_TIME_H 71 # include <sys/time.h> 72 #endif 73 #include <sys/socket.h> 74 75 #include <ctype.h> 76 #include <errno.h> 77 #ifdef HAVE_PATHS_H 78 #include <paths.h> 79 #endif 80 #include <signal.h> 81 #include <stdarg.h> 82 #include <stdio.h> 83 #include <stdlib.h> 84 #include <string.h> 85 #include <termios.h> 86 #include <pwd.h> 87 #include <unistd.h> 88 89 #include "openbsd-compat/sys-queue.h" 90 #include "xmalloc.h" 91 #include "ssh.h" 92 #include "ssh1.h" 93 #include "ssh2.h" 94 #include "packet.h" 95 #include "buffer.h" 96 #include "compat.h" 97 #include "channels.h" 98 #include "dispatch.h" 99 #include "key.h" 100 #include "cipher.h" 101 #include "kex.h" 102 #include "log.h" 103 #include "readconf.h" 104 #include "clientloop.h" 105 #include "sshconnect.h" 106 #include "authfd.h" 107 #include "atomicio.h" 108 #include "sshpty.h" 109 #include "misc.h" 110 #include "monitor_fdpass.h" 111 #include "match.h" 112 #include "msg.h" 113 114 /* import options */ 115 extern Options options; 116 117 /* Flag indicating that stdin should be redirected from /dev/null. */ 118 extern int stdin_null_flag; 119 120 /* Flag indicating that no shell has been requested */ 121 extern int no_shell_flag; 122 123 /* Control socket */ 124 extern int muxserver_sock; 125 126 /* 127 * Name of the host we are connecting to. This is the name given on the 128 * command line, or the HostName specified for the user-supplied name in a 129 * configuration file. 130 */ 131 extern char *host; 132 133 /* 134 * Flag to indicate that we have received a window change signal which has 135 * not yet been processed. This will cause a message indicating the new 136 * window size to be sent to the server a little later. This is volatile 137 * because this is updated in a signal handler. 138 */ 139 static volatile sig_atomic_t received_window_change_signal = 0; 140 static volatile sig_atomic_t received_signal = 0; 141 142 /* Flag indicating whether the user's terminal is in non-blocking mode. */ 143 static int in_non_blocking_mode = 0; 144 145 /* Common data for the client loop code. */ 146 static volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */ 147 static int escape_char1; /* Escape character. (proto1 only) */ 148 static int escape_pending1; /* Last character was an escape (proto1 only) */ 149 static int last_was_cr; /* Last character was a newline. */ 150 static int exit_status; /* Used to store the command exit status. */ 151 static int stdin_eof; /* EOF has been encountered on stderr. */ 152 static Buffer stdin_buffer; /* Buffer for stdin data. */ 153 static Buffer stdout_buffer; /* Buffer for stdout data. */ 154 static Buffer stderr_buffer; /* Buffer for stderr data. */ 155 static u_int buffer_high;/* Soft max buffer size. */ 156 static int connection_in; /* Connection to server (input). */ 157 static int connection_out; /* Connection to server (output). */ 158 static int need_rekeying; /* Set to non-zero if rekeying is requested. */ 159 static int session_closed = 0; /* In SSH2: login session closed. */ 160 161 static void client_init_dispatch(void); 162 int session_ident = -1; 163 164 /* Track escape per proto2 channel */ 165 struct escape_filter_ctx { 166 int escape_pending; 167 int escape_char; 168 }; 169 170 /* Context for channel confirmation replies */ 171 struct channel_reply_ctx { 172 const char *request_type; 173 int id, do_close; 174 }; 175 176 /* Global request success/failure callbacks */ 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 /*XXX*/ 188 extern Kex *xxx_kex; 189 190 void ssh_process_session2_setup(int, int, int, Buffer *); 191 192 /* Restores stdin to blocking mode. */ 193 194 static void 195 leave_non_blocking(void) 196 { 197 if (in_non_blocking_mode) { 198 unset_nonblock(fileno(stdin)); 199 in_non_blocking_mode = 0; 200 } 201 } 202 203 /* Puts stdin terminal in non-blocking mode. */ 204 205 static void 206 enter_non_blocking(void) 207 { 208 in_non_blocking_mode = 1; 209 set_nonblock(fileno(stdin)); 210 } 211 212 /* 213 * Signal handler for the window change signal (SIGWINCH). This just sets a 214 * flag indicating that the window has changed. 215 */ 216 /*ARGSUSED */ 217 static void 218 window_change_handler(int sig) 219 { 220 received_window_change_signal = 1; 221 signal(SIGWINCH, window_change_handler); 222 } 223 224 /* 225 * Signal handler for signals that cause the program to terminate. These 226 * signals must be trapped to restore terminal modes. 227 */ 228 /*ARGSUSED */ 229 static void 230 signal_handler(int sig) 231 { 232 received_signal = sig; 233 quit_pending = 1; 234 } 235 236 /* 237 * Returns current time in seconds from Jan 1, 1970 with the maximum 238 * available resolution. 239 */ 240 241 static double 242 get_current_time(void) 243 { 244 struct timeval tv; 245 gettimeofday(&tv, NULL); 246 return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0; 247 } 248 249 #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1" 250 void 251 client_x11_get_proto(const char *display, const char *xauth_path, 252 u_int trusted, char **_proto, char **_data) 253 { 254 char cmd[1024]; 255 char line[512]; 256 char xdisplay[512]; 257 static char proto[512], data[512]; 258 FILE *f; 259 int got_data = 0, generated = 0, do_unlink = 0, i; 260 char *xauthdir, *xauthfile; 261 struct stat st; 262 263 xauthdir = xauthfile = NULL; 264 *_proto = proto; 265 *_data = data; 266 proto[0] = data[0] = '\0'; 267 268 if (xauth_path == NULL ||(stat(xauth_path, &st) == -1)) { 269 debug("No xauth program."); 270 } else { 271 if (display == NULL) { 272 debug("x11_get_proto: DISPLAY not set"); 273 return; 274 } 275 /* 276 * Handle FamilyLocal case where $DISPLAY does 277 * not match an authorization entry. For this we 278 * just try "xauth list unix:displaynum.screennum". 279 * XXX: "localhost" match to determine FamilyLocal 280 * is not perfect. 281 */ 282 if (strncmp(display, "localhost:", 10) == 0) { 283 snprintf(xdisplay, sizeof(xdisplay), "unix:%s", 284 display + 10); 285 display = xdisplay; 286 } 287 if (trusted == 0) { 288 xauthdir = xmalloc(MAXPATHLEN); 289 xauthfile = xmalloc(MAXPATHLEN); 290 strlcpy(xauthdir, "/tmp/ssh-XXXXXXXXXX", MAXPATHLEN); 291 if (mkdtemp(xauthdir) != NULL) { 292 do_unlink = 1; 293 snprintf(xauthfile, MAXPATHLEN, "%s/xauthfile", 294 xauthdir); 295 snprintf(cmd, sizeof(cmd), 296 "%s -f %s generate %s " SSH_X11_PROTO 297 " untrusted timeout 1200 2>" _PATH_DEVNULL, 298 xauth_path, xauthfile, display); 299 debug2("x11_get_proto: %s", cmd); 300 if (system(cmd) == 0) 301 generated = 1; 302 } 303 } 304 305 /* 306 * When in untrusted mode, we read the cookie only if it was 307 * successfully generated as an untrusted one in the step 308 * above. 309 */ 310 if (trusted || generated) { 311 snprintf(cmd, sizeof(cmd), 312 "%s %s%s list %s 2>" _PATH_DEVNULL, 313 xauth_path, 314 generated ? "-f " : "" , 315 generated ? xauthfile : "", 316 display); 317 debug2("x11_get_proto: %s", cmd); 318 f = popen(cmd, "r"); 319 if (f && fgets(line, sizeof(line), f) && 320 sscanf(line, "%*s %511s %511s", proto, data) == 2) 321 got_data = 1; 322 if (f) 323 pclose(f); 324 } else 325 error("Warning: untrusted X11 forwarding setup failed: " 326 "xauth key data not generated"); 327 } 328 329 if (do_unlink) { 330 unlink(xauthfile); 331 rmdir(xauthdir); 332 } 333 if (xauthdir) 334 xfree(xauthdir); 335 if (xauthfile) 336 xfree(xauthfile); 337 338 /* 339 * If we didn't get authentication data, just make up some 340 * data. The forwarding code will check the validity of the 341 * response anyway, and substitute this data. The X11 342 * server, however, will ignore this fake data and use 343 * whatever authentication mechanisms it was using otherwise 344 * for the local connection. 345 */ 346 if (!got_data) { 347 u_int32_t rnd = 0; 348 349 logit("Warning: No xauth data; " 350 "using fake authentication data for X11 forwarding."); 351 strlcpy(proto, SSH_X11_PROTO, sizeof proto); 352 for (i = 0; i < 16; i++) { 353 if (i % 4 == 0) 354 rnd = arc4random(); 355 snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", 356 rnd & 0xff); 357 rnd >>= 8; 358 } 359 } 360 } 361 362 /* 363 * This is called when the interactive is entered. This checks if there is 364 * an EOF coming on stdin. We must check this explicitly, as select() does 365 * not appear to wake up when redirecting from /dev/null. 366 */ 367 368 static void 369 client_check_initial_eof_on_stdin(void) 370 { 371 int len; 372 char buf[1]; 373 374 /* 375 * If standard input is to be "redirected from /dev/null", we simply 376 * mark that we have seen an EOF and send an EOF message to the 377 * server. Otherwise, we try to read a single character; it appears 378 * that for some files, such /dev/null, select() never wakes up for 379 * read for this descriptor, which means that we never get EOF. This 380 * way we will get the EOF if stdin comes from /dev/null or similar. 381 */ 382 if (stdin_null_flag) { 383 /* Fake EOF on stdin. */ 384 debug("Sending eof."); 385 stdin_eof = 1; 386 packet_start(SSH_CMSG_EOF); 387 packet_send(); 388 } else { 389 enter_non_blocking(); 390 391 /* Check for immediate EOF on stdin. */ 392 len = read(fileno(stdin), buf, 1); 393 if (len == 0) { 394 /* 395 * EOF. Record that we have seen it and send 396 * EOF to server. 397 */ 398 debug("Sending eof."); 399 stdin_eof = 1; 400 packet_start(SSH_CMSG_EOF); 401 packet_send(); 402 } else if (len > 0) { 403 /* 404 * Got data. We must store the data in the buffer, 405 * and also process it as an escape character if 406 * appropriate. 407 */ 408 if ((u_char) buf[0] == escape_char1) 409 escape_pending1 = 1; 410 else 411 buffer_append(&stdin_buffer, buf, 1); 412 } 413 leave_non_blocking(); 414 } 415 } 416 417 418 /* 419 * Make packets from buffered stdin data, and buffer them for sending to the 420 * connection. 421 */ 422 423 static void 424 client_make_packets_from_stdin_data(void) 425 { 426 u_int len; 427 428 /* Send buffered stdin data to the server. */ 429 while (buffer_len(&stdin_buffer) > 0 && 430 packet_not_very_much_data_to_write()) { 431 len = buffer_len(&stdin_buffer); 432 /* Keep the packets at reasonable size. */ 433 if (len > packet_get_maxsize()) 434 len = packet_get_maxsize(); 435 packet_start(SSH_CMSG_STDIN_DATA); 436 packet_put_string(buffer_ptr(&stdin_buffer), len); 437 packet_send(); 438 buffer_consume(&stdin_buffer, len); 439 /* If we have a pending EOF, send it now. */ 440 if (stdin_eof && buffer_len(&stdin_buffer) == 0) { 441 packet_start(SSH_CMSG_EOF); 442 packet_send(); 443 } 444 } 445 } 446 447 /* 448 * Checks if the client window has changed, and sends a packet about it to 449 * the server if so. The actual change is detected elsewhere (by a software 450 * interrupt on Unix); this just checks the flag and sends a message if 451 * appropriate. 452 */ 453 454 static void 455 client_check_window_change(void) 456 { 457 struct winsize ws; 458 459 if (! received_window_change_signal) 460 return; 461 /** XXX race */ 462 received_window_change_signal = 0; 463 464 debug2("client_check_window_change: changed"); 465 466 if (compat20) { 467 channel_send_window_changes(); 468 } else { 469 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) 470 return; 471 packet_start(SSH_CMSG_WINDOW_SIZE); 472 packet_put_int((u_int)ws.ws_row); 473 packet_put_int((u_int)ws.ws_col); 474 packet_put_int((u_int)ws.ws_xpixel); 475 packet_put_int((u_int)ws.ws_ypixel); 476 packet_send(); 477 } 478 } 479 480 static void 481 client_global_request_reply(int type, u_int32_t seq, void *ctxt) 482 { 483 struct global_confirm *gc; 484 485 if ((gc = TAILQ_FIRST(&global_confirms)) == NULL) 486 return; 487 if (gc->cb != NULL) 488 gc->cb(type, seq, gc->ctx); 489 if (--gc->ref_count <= 0) { 490 TAILQ_REMOVE(&global_confirms, gc, entry); 491 bzero(gc, sizeof(*gc)); 492 xfree(gc); 493 } 494 495 keep_alive_timeouts = 0; 496 } 497 498 static void 499 server_alive_check(void) 500 { 501 if (++keep_alive_timeouts > options.server_alive_count_max) { 502 logit("Timeout, server not responding."); 503 cleanup_exit(255); 504 } 505 packet_start(SSH2_MSG_GLOBAL_REQUEST); 506 packet_put_cstring("keepalive@openssh.com"); 507 packet_put_char(1); /* boolean: want reply */ 508 packet_send(); 509 /* Insert an empty placeholder to maintain ordering */ 510 client_register_global_confirm(NULL, NULL); 511 } 512 513 /* 514 * Waits until the client can do something (some data becomes available on 515 * one of the file descriptors). 516 */ 517 static void 518 client_wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, 519 int *maxfdp, u_int *nallocp, int rekeying) 520 { 521 struct timeval tv, *tvp; 522 int ret; 523 524 /* Add any selections by the channel mechanism. */ 525 channel_prepare_select(readsetp, writesetp, maxfdp, nallocp, rekeying); 526 527 if (!compat20) { 528 /* Read from the connection, unless our buffers are full. */ 529 if (buffer_len(&stdout_buffer) < buffer_high && 530 buffer_len(&stderr_buffer) < buffer_high && 531 channel_not_very_much_buffered_data()) 532 FD_SET(connection_in, *readsetp); 533 /* 534 * Read from stdin, unless we have seen EOF or have very much 535 * buffered data to send to the server. 536 */ 537 if (!stdin_eof && packet_not_very_much_data_to_write()) 538 FD_SET(fileno(stdin), *readsetp); 539 540 /* Select stdout/stderr if have data in buffer. */ 541 if (buffer_len(&stdout_buffer) > 0) 542 FD_SET(fileno(stdout), *writesetp); 543 if (buffer_len(&stderr_buffer) > 0) 544 FD_SET(fileno(stderr), *writesetp); 545 } else { 546 /* channel_prepare_select could have closed the last channel */ 547 if (session_closed && !channel_still_open() && 548 !packet_have_data_to_write()) { 549 /* clear mask since we did not call select() */ 550 memset(*readsetp, 0, *nallocp); 551 memset(*writesetp, 0, *nallocp); 552 return; 553 } else { 554 FD_SET(connection_in, *readsetp); 555 } 556 } 557 558 /* Select server connection if have data to write to the server. */ 559 if (packet_have_data_to_write()) 560 FD_SET(connection_out, *writesetp); 561 562 if (muxserver_sock != -1) 563 FD_SET(muxserver_sock, *readsetp); 564 565 /* 566 * Wait for something to happen. This will suspend the process until 567 * some selected descriptor can be read, written, or has some other 568 * event pending. 569 */ 570 571 if (options.server_alive_interval == 0 || !compat20) 572 tvp = NULL; 573 else { 574 tv.tv_sec = options.server_alive_interval; 575 tv.tv_usec = 0; 576 tvp = &tv; 577 } 578 ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp); 579 if (ret < 0) { 580 char buf[100]; 581 582 /* 583 * We have to clear the select masks, because we return. 584 * We have to return, because the mainloop checks for the flags 585 * set by the signal handlers. 586 */ 587 memset(*readsetp, 0, *nallocp); 588 memset(*writesetp, 0, *nallocp); 589 590 if (errno == EINTR) 591 return; 592 /* Note: we might still have data in the buffers. */ 593 snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno)); 594 buffer_append(&stderr_buffer, buf, strlen(buf)); 595 quit_pending = 1; 596 } else if (ret == 0) 597 server_alive_check(); 598 } 599 600 static void 601 client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr) 602 { 603 /* Flush stdout and stderr buffers. */ 604 if (buffer_len(bout) > 0) 605 atomicio(vwrite, fileno(stdout), buffer_ptr(bout), 606 buffer_len(bout)); 607 if (buffer_len(berr) > 0) 608 atomicio(vwrite, fileno(stderr), buffer_ptr(berr), 609 buffer_len(berr)); 610 611 leave_raw_mode(); 612 613 /* 614 * Free (and clear) the buffer to reduce the amount of data that gets 615 * written to swap. 616 */ 617 buffer_free(bin); 618 buffer_free(bout); 619 buffer_free(berr); 620 621 /* Send the suspend signal to the program itself. */ 622 kill(getpid(), SIGTSTP); 623 624 /* Reset window sizes in case they have changed */ 625 received_window_change_signal = 1; 626 627 /* OK, we have been continued by the user. Reinitialize buffers. */ 628 buffer_init(bin); 629 buffer_init(bout); 630 buffer_init(berr); 631 632 enter_raw_mode(); 633 } 634 635 static void 636 client_process_net_input(fd_set *readset) 637 { 638 int len; 639 char buf[8192]; 640 641 /* 642 * Read input from the server, and add any such data to the buffer of 643 * the packet subsystem. 644 */ 645 if (FD_ISSET(connection_in, readset)) { 646 /* Read as much as possible. */ 647 len = read(connection_in, buf, sizeof(buf)); 648 if (len == 0) { 649 /* 650 * Received EOF. The remote host has closed the 651 * connection. 652 */ 653 snprintf(buf, sizeof buf, 654 "Connection to %.300s closed by remote host.\r\n", 655 host); 656 buffer_append(&stderr_buffer, buf, strlen(buf)); 657 quit_pending = 1; 658 return; 659 } 660 /* 661 * There is a kernel bug on Solaris that causes select to 662 * sometimes wake up even though there is no data available. 663 */ 664 if (len < 0 && 665 (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK)) 666 len = 0; 667 668 if (len < 0) { 669 /* 670 * An error has encountered. Perhaps there is a 671 * network problem. 672 */ 673 snprintf(buf, sizeof buf, 674 "Read from remote host %.300s: %.100s\r\n", 675 host, strerror(errno)); 676 buffer_append(&stderr_buffer, buf, strlen(buf)); 677 quit_pending = 1; 678 return; 679 } 680 packet_process_incoming(buf, len); 681 } 682 } 683 684 static void 685 client_status_confirm(int type, Channel *c, void *ctx) 686 { 687 struct channel_reply_ctx *cr = (struct channel_reply_ctx *)ctx; 688 char errmsg[256]; 689 int tochan; 690 691 /* XXX supress on mux _client_ quietmode */ 692 tochan = options.log_level >= SYSLOG_LEVEL_ERROR && 693 c->ctl_fd != -1 && c->extended_usage == CHAN_EXTENDED_WRITE; 694 695 if (type == SSH2_MSG_CHANNEL_SUCCESS) { 696 debug2("%s request accepted on channel %d", 697 cr->request_type, c->self); 698 } else if (type == SSH2_MSG_CHANNEL_FAILURE) { 699 if (tochan) { 700 snprintf(errmsg, sizeof(errmsg), 701 "%s request failed\r\n", cr->request_type); 702 } else { 703 snprintf(errmsg, sizeof(errmsg), 704 "%s request failed on channel %d", 705 cr->request_type, c->self); 706 } 707 /* If error occurred on primary session channel, then exit */ 708 if (cr->do_close && c->self == session_ident) 709 fatal("%s", errmsg); 710 /* If error occurred on mux client, append to their stderr */ 711 if (tochan) 712 buffer_append(&c->extended, errmsg, strlen(errmsg)); 713 else 714 error("%s", errmsg); 715 if (cr->do_close) { 716 chan_read_failed(c); 717 chan_write_failed(c); 718 } 719 } 720 xfree(cr); 721 } 722 723 static void 724 client_abandon_status_confirm(Channel *c, void *ctx) 725 { 726 xfree(ctx); 727 } 728 729 static void 730 client_expect_confirm(int id, const char *request, int do_close) 731 { 732 struct channel_reply_ctx *cr = xmalloc(sizeof(*cr)); 733 734 cr->request_type = request; 735 cr->do_close = do_close; 736 737 channel_register_status_confirm(id, client_status_confirm, 738 client_abandon_status_confirm, cr); 739 } 740 741 void 742 client_register_global_confirm(global_confirm_cb *cb, void *ctx) 743 { 744 struct global_confirm *gc, *last_gc; 745 746 /* Coalesce identical callbacks */ 747 last_gc = TAILQ_LAST(&global_confirms, global_confirms); 748 if (last_gc && last_gc->cb == cb && last_gc->ctx == ctx) { 749 if (++last_gc->ref_count >= INT_MAX) 750 fatal("%s: last_gc->ref_count = %d", 751 __func__, last_gc->ref_count); 752 return; 753 } 754 755 gc = xmalloc(sizeof(*gc)); 756 gc->cb = cb; 757 gc->ctx = ctx; 758 gc->ref_count = 1; 759 TAILQ_INSERT_TAIL(&global_confirms, gc, entry); 760 } 761 762 static void 763 process_cmdline(void) 764 { 765 void (*handler)(int); 766 char *s, *cmd, *cancel_host; 767 int delete = 0; 768 int local = 0; 769 u_short cancel_port; 770 Forward fwd; 771 772 bzero(&fwd, sizeof(fwd)); 773 fwd.listen_host = fwd.connect_host = NULL; 774 775 leave_raw_mode(); 776 handler = signal(SIGINT, SIG_IGN); 777 cmd = s = read_passphrase("\r\nssh> ", RP_ECHO); 778 if (s == NULL) 779 goto out; 780 while (isspace(*s)) 781 s++; 782 if (*s == '-') 783 s++; /* Skip cmdline '-', if any */ 784 if (*s == '\0') 785 goto out; 786 787 if (*s == 'h' || *s == 'H' || *s == '?') { 788 logit("Commands:"); 789 logit(" -L[bind_address:]port:host:hostport " 790 "Request local forward"); 791 logit(" -R[bind_address:]port:host:hostport " 792 "Request remote forward"); 793 logit(" -KR[bind_address:]port " 794 "Cancel remote forward"); 795 if (!options.permit_local_command) 796 goto out; 797 logit(" !args " 798 "Execute local command"); 799 goto out; 800 } 801 802 if (*s == '!' && options.permit_local_command) { 803 s++; 804 ssh_local_cmd(s); 805 goto out; 806 } 807 808 if (*s == 'K') { 809 delete = 1; 810 s++; 811 } 812 if (*s != 'L' && *s != 'R') { 813 logit("Invalid command."); 814 goto out; 815 } 816 if (*s == 'L') 817 local = 1; 818 if (local && delete) { 819 logit("Not supported."); 820 goto out; 821 } 822 if ((!local || delete) && !compat20) { 823 logit("Not supported for SSH protocol version 1."); 824 goto out; 825 } 826 827 while (isspace(*++s)) 828 ; 829 830 if (delete) { 831 cancel_port = 0; 832 cancel_host = hpdelim(&s); /* may be NULL */ 833 if (s != NULL) { 834 cancel_port = a2port(s); 835 cancel_host = cleanhostname(cancel_host); 836 } else { 837 cancel_port = a2port(cancel_host); 838 cancel_host = NULL; 839 } 840 if (cancel_port == 0) { 841 logit("Bad forwarding close port"); 842 goto out; 843 } 844 channel_request_rforward_cancel(cancel_host, cancel_port); 845 } else { 846 if (!parse_forward(&fwd, s)) { 847 logit("Bad forwarding specification."); 848 goto out; 849 } 850 if (local) { 851 if (channel_setup_local_fwd_listener(fwd.listen_host, 852 fwd.listen_port, fwd.connect_host, 853 fwd.connect_port, options.gateway_ports) < 0) { 854 logit("Port forwarding failed."); 855 goto out; 856 } 857 } else { 858 if (channel_request_remote_forwarding(fwd.listen_host, 859 fwd.listen_port, fwd.connect_host, 860 fwd.connect_port) < 0) { 861 logit("Port forwarding failed."); 862 goto out; 863 } 864 } 865 866 logit("Forwarding port."); 867 } 868 869 out: 870 signal(SIGINT, handler); 871 enter_raw_mode(); 872 if (cmd) 873 xfree(cmd); 874 if (fwd.listen_host != NULL) 875 xfree(fwd.listen_host); 876 if (fwd.connect_host != NULL) 877 xfree(fwd.connect_host); 878 } 879 880 /* 881 * Process the characters one by one, call with c==NULL for proto1 case. 882 */ 883 static int 884 process_escapes(Channel *c, Buffer *bin, Buffer *bout, Buffer *berr, 885 char *buf, int len) 886 { 887 char string[1024]; 888 pid_t pid; 889 int bytes = 0; 890 u_int i; 891 u_char ch; 892 char *s; 893 int *escape_pendingp, escape_char; 894 struct escape_filter_ctx *efc; 895 896 if (c == NULL) { 897 escape_pendingp = &escape_pending1; 898 escape_char = escape_char1; 899 } else { 900 if (c->filter_ctx == NULL) 901 return 0; 902 efc = (struct escape_filter_ctx *)c->filter_ctx; 903 escape_pendingp = &efc->escape_pending; 904 escape_char = efc->escape_char; 905 } 906 907 if (len <= 0) 908 return (0); 909 910 for (i = 0; i < (u_int)len; i++) { 911 /* Get one character at a time. */ 912 ch = buf[i]; 913 914 if (*escape_pendingp) { 915 /* We have previously seen an escape character. */ 916 /* Clear the flag now. */ 917 *escape_pendingp = 0; 918 919 /* Process the escaped character. */ 920 switch (ch) { 921 case '.': 922 /* Terminate the connection. */ 923 snprintf(string, sizeof string, "%c.\r\n", 924 escape_char); 925 buffer_append(berr, string, strlen(string)); 926 927 if (c && c->ctl_fd != -1) { 928 chan_read_failed(c); 929 chan_write_failed(c); 930 return 0; 931 } else 932 quit_pending = 1; 933 return -1; 934 935 case 'Z' - 64: 936 /* XXX support this for mux clients */ 937 if (c && c->ctl_fd != -1) { 938 noescape: 939 snprintf(string, sizeof string, 940 "%c%c escape not available to " 941 "multiplexed sessions\r\n", 942 escape_char, ch); 943 buffer_append(berr, string, 944 strlen(string)); 945 continue; 946 } 947 /* Suspend the program. Inform the user */ 948 snprintf(string, sizeof string, 949 "%c^Z [suspend ssh]\r\n", escape_char); 950 buffer_append(berr, string, strlen(string)); 951 952 /* Restore terminal modes and suspend. */ 953 client_suspend_self(bin, bout, berr); 954 955 /* We have been continued. */ 956 continue; 957 958 case 'B': 959 if (compat20) { 960 snprintf(string, sizeof string, 961 "%cB\r\n", escape_char); 962 buffer_append(berr, string, 963 strlen(string)); 964 channel_request_start(session_ident, 965 "break", 0); 966 packet_put_int(1000); 967 packet_send(); 968 } 969 continue; 970 971 case 'R': 972 if (compat20) { 973 if (datafellows & SSH_BUG_NOREKEY) 974 logit("Server does not " 975 "support re-keying"); 976 else 977 need_rekeying = 1; 978 } 979 continue; 980 981 case '&': 982 if (c && c->ctl_fd != -1) 983 goto noescape; 984 /* 985 * Detach the program (continue to serve 986 * connections, but put in background and no 987 * more new connections). 988 */ 989 /* Restore tty modes. */ 990 leave_raw_mode(); 991 992 /* Stop listening for new connections. */ 993 channel_stop_listening(); 994 995 snprintf(string, sizeof string, 996 "%c& [backgrounded]\n", escape_char); 997 buffer_append(berr, string, strlen(string)); 998 999 /* Fork into background. */ 1000 pid = fork(); 1001 if (pid < 0) { 1002 error("fork: %.100s", strerror(errno)); 1003 continue; 1004 } 1005 if (pid != 0) { /* This is the parent. */ 1006 /* The parent just exits. */ 1007 exit(0); 1008 } 1009 /* The child continues serving connections. */ 1010 if (compat20) { 1011 buffer_append(bin, "\004", 1); 1012 /* fake EOF on stdin */ 1013 return -1; 1014 } else if (!stdin_eof) { 1015 /* 1016 * Sending SSH_CMSG_EOF alone does not 1017 * always appear to be enough. So we 1018 * try to send an EOF character first. 1019 */ 1020 packet_start(SSH_CMSG_STDIN_DATA); 1021 packet_put_string("\004", 1); 1022 packet_send(); 1023 /* Close stdin. */ 1024 stdin_eof = 1; 1025 if (buffer_len(bin) == 0) { 1026 packet_start(SSH_CMSG_EOF); 1027 packet_send(); 1028 } 1029 } 1030 continue; 1031 1032 case '?': 1033 if (c && c->ctl_fd != -1) { 1034 snprintf(string, sizeof string, 1035 "%c?\r\n\ 1036 Supported escape sequences:\r\n\ 1037 %c. - terminate session\r\n\ 1038 %cB - send a BREAK to the remote system\r\n\ 1039 %cC - open a command line\r\n\ 1040 %cR - Request rekey (SSH protocol 2 only)\r\n\ 1041 %c# - list forwarded connections\r\n\ 1042 %c? - this message\r\n\ 1043 %c%c - send the escape character by typing it twice\r\n\ 1044 (Note that escapes are only recognized immediately after newline.)\r\n", 1045 escape_char, escape_char, 1046 escape_char, escape_char, 1047 escape_char, escape_char, 1048 escape_char, escape_char, 1049 escape_char); 1050 } else { 1051 snprintf(string, sizeof string, 1052 "%c?\r\n\ 1053 Supported escape sequences:\r\n\ 1054 %c. - terminate connection (and any multiplexed sessions)\r\n\ 1055 %cB - send a BREAK to the remote system\r\n\ 1056 %cC - open a command line\r\n\ 1057 %cR - Request rekey (SSH protocol 2 only)\r\n\ 1058 %c^Z - suspend ssh\r\n\ 1059 %c# - list forwarded connections\r\n\ 1060 %c& - background ssh (when waiting for connections to terminate)\r\n\ 1061 %c? - this message\r\n\ 1062 %c%c - send the escape character by typing it twice\r\n\ 1063 (Note that escapes are only recognized immediately after newline.)\r\n", 1064 escape_char, escape_char, 1065 escape_char, escape_char, 1066 escape_char, escape_char, 1067 escape_char, escape_char, 1068 escape_char, escape_char, 1069 escape_char); 1070 } 1071 buffer_append(berr, string, strlen(string)); 1072 continue; 1073 1074 case '#': 1075 snprintf(string, sizeof string, "%c#\r\n", 1076 escape_char); 1077 buffer_append(berr, string, strlen(string)); 1078 s = channel_open_message(); 1079 buffer_append(berr, s, strlen(s)); 1080 xfree(s); 1081 continue; 1082 1083 case 'C': 1084 process_cmdline(); 1085 continue; 1086 1087 default: 1088 if (ch != escape_char) { 1089 buffer_put_char(bin, escape_char); 1090 bytes++; 1091 } 1092 /* Escaped characters fall through here */ 1093 break; 1094 } 1095 } else { 1096 /* 1097 * The previous character was not an escape char. 1098 * Check if this is an escape. 1099 */ 1100 if (last_was_cr && ch == escape_char) { 1101 /* 1102 * It is. Set the flag and continue to 1103 * next character. 1104 */ 1105 *escape_pendingp = 1; 1106 continue; 1107 } 1108 } 1109 1110 /* 1111 * Normal character. Record whether it was a newline, 1112 * and append it to the buffer. 1113 */ 1114 last_was_cr = (ch == '\r' || ch == '\n'); 1115 buffer_put_char(bin, ch); 1116 bytes++; 1117 } 1118 return bytes; 1119 } 1120 1121 static void 1122 client_process_input(fd_set *readset) 1123 { 1124 int len; 1125 char buf[8192]; 1126 1127 /* Read input from stdin. */ 1128 if (FD_ISSET(fileno(stdin), readset)) { 1129 /* Read as much as possible. */ 1130 len = read(fileno(stdin), buf, sizeof(buf)); 1131 if (len < 0 && 1132 (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK)) 1133 return; /* we'll try again later */ 1134 if (len <= 0) { 1135 /* 1136 * Received EOF or error. They are treated 1137 * similarly, except that an error message is printed 1138 * if it was an error condition. 1139 */ 1140 if (len < 0) { 1141 snprintf(buf, sizeof buf, "read: %.100s\r\n", 1142 strerror(errno)); 1143 buffer_append(&stderr_buffer, buf, strlen(buf)); 1144 } 1145 /* Mark that we have seen EOF. */ 1146 stdin_eof = 1; 1147 /* 1148 * Send an EOF message to the server unless there is 1149 * data in the buffer. If there is data in the 1150 * buffer, no message will be sent now. Code 1151 * elsewhere will send the EOF when the buffer 1152 * becomes empty if stdin_eof is set. 1153 */ 1154 if (buffer_len(&stdin_buffer) == 0) { 1155 packet_start(SSH_CMSG_EOF); 1156 packet_send(); 1157 } 1158 } else if (escape_char1 == SSH_ESCAPECHAR_NONE) { 1159 /* 1160 * Normal successful read, and no escape character. 1161 * Just append the data to buffer. 1162 */ 1163 buffer_append(&stdin_buffer, buf, len); 1164 } else { 1165 /* 1166 * Normal, successful read. But we have an escape 1167 * character and have to process the characters one 1168 * by one. 1169 */ 1170 if (process_escapes(NULL, &stdin_buffer, 1171 &stdout_buffer, &stderr_buffer, buf, len) == -1) 1172 return; 1173 } 1174 } 1175 } 1176 1177 static void 1178 client_process_output(fd_set *writeset) 1179 { 1180 int len; 1181 char buf[100]; 1182 1183 /* Write buffered output to stdout. */ 1184 if (FD_ISSET(fileno(stdout), writeset)) { 1185 /* Write as much data as possible. */ 1186 len = write(fileno(stdout), buffer_ptr(&stdout_buffer), 1187 buffer_len(&stdout_buffer)); 1188 if (len <= 0) { 1189 if (errno == EINTR || errno == EAGAIN || 1190 errno == EWOULDBLOCK) 1191 len = 0; 1192 else { 1193 /* 1194 * An error or EOF was encountered. Put an 1195 * error message to stderr buffer. 1196 */ 1197 snprintf(buf, sizeof buf, 1198 "write stdout: %.50s\r\n", strerror(errno)); 1199 buffer_append(&stderr_buffer, buf, strlen(buf)); 1200 quit_pending = 1; 1201 return; 1202 } 1203 } 1204 /* Consume printed data from the buffer. */ 1205 buffer_consume(&stdout_buffer, len); 1206 } 1207 /* Write buffered output to stderr. */ 1208 if (FD_ISSET(fileno(stderr), writeset)) { 1209 /* Write as much data as possible. */ 1210 len = write(fileno(stderr), buffer_ptr(&stderr_buffer), 1211 buffer_len(&stderr_buffer)); 1212 if (len <= 0) { 1213 if (errno == EINTR || errno == EAGAIN || 1214 errno == EWOULDBLOCK) 1215 len = 0; 1216 else { 1217 /* 1218 * EOF or error, but can't even print 1219 * error message. 1220 */ 1221 quit_pending = 1; 1222 return; 1223 } 1224 } 1225 /* Consume printed characters from the buffer. */ 1226 buffer_consume(&stderr_buffer, len); 1227 } 1228 } 1229 1230 /* 1231 * Get packets from the connection input buffer, and process them as long as 1232 * there are packets available. 1233 * 1234 * Any unknown packets received during the actual 1235 * session cause the session to terminate. This is 1236 * intended to make debugging easier since no 1237 * confirmations are sent. Any compatible protocol 1238 * extensions must be negotiated during the 1239 * preparatory phase. 1240 */ 1241 1242 static void 1243 client_process_buffered_input_packets(void) 1244 { 1245 dispatch_run(DISPATCH_NONBLOCK, &quit_pending, 1246 compat20 ? xxx_kex : NULL); 1247 } 1248 1249 /* scan buf[] for '~' before sending data to the peer */ 1250 1251 /* Helper: allocate a new escape_filter_ctx and fill in its escape char */ 1252 void * 1253 client_new_escape_filter_ctx(int escape_char) 1254 { 1255 struct escape_filter_ctx *ret; 1256 1257 ret = xmalloc(sizeof(*ret)); 1258 ret->escape_pending = 0; 1259 ret->escape_char = escape_char; 1260 return (void *)ret; 1261 } 1262 1263 /* Free the escape filter context on channel free */ 1264 void 1265 client_filter_cleanup(int cid, void *ctx) 1266 { 1267 xfree(ctx); 1268 } 1269 1270 int 1271 client_simple_escape_filter(Channel *c, char *buf, int len) 1272 { 1273 if (c->extended_usage != CHAN_EXTENDED_WRITE) 1274 return 0; 1275 1276 return process_escapes(c, &c->input, &c->output, &c->extended, 1277 buf, len); 1278 } 1279 1280 static void 1281 client_channel_closed(int id, void *arg) 1282 { 1283 channel_cancel_cleanup(id); 1284 session_closed = 1; 1285 leave_raw_mode(); 1286 } 1287 1288 /* 1289 * Implements the interactive session with the server. This is called after 1290 * the user has been authenticated, and a command has been started on the 1291 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character 1292 * used as an escape character for terminating or suspending the session. 1293 */ 1294 1295 int 1296 client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id) 1297 { 1298 fd_set *readset = NULL, *writeset = NULL; 1299 double start_time, total_time; 1300 int max_fd = 0, max_fd2 = 0, len, rekeying = 0; 1301 u_int64_t ibytes, obytes; 1302 u_int nalloc = 0; 1303 char buf[100]; 1304 1305 debug("Entering interactive session."); 1306 1307 start_time = get_current_time(); 1308 1309 /* Initialize variables. */ 1310 escape_pending1 = 0; 1311 last_was_cr = 1; 1312 exit_status = -1; 1313 stdin_eof = 0; 1314 buffer_high = 64 * 1024; 1315 connection_in = packet_get_connection_in(); 1316 connection_out = packet_get_connection_out(); 1317 max_fd = MAX(connection_in, connection_out); 1318 if (muxserver_sock != -1) 1319 max_fd = MAX(max_fd, muxserver_sock); 1320 1321 if (!compat20) { 1322 /* enable nonblocking unless tty */ 1323 if (!isatty(fileno(stdin))) 1324 set_nonblock(fileno(stdin)); 1325 if (!isatty(fileno(stdout))) 1326 set_nonblock(fileno(stdout)); 1327 if (!isatty(fileno(stderr))) 1328 set_nonblock(fileno(stderr)); 1329 max_fd = MAX(max_fd, fileno(stdin)); 1330 max_fd = MAX(max_fd, fileno(stdout)); 1331 max_fd = MAX(max_fd, fileno(stderr)); 1332 } 1333 quit_pending = 0; 1334 escape_char1 = escape_char_arg; 1335 1336 /* Initialize buffers. */ 1337 buffer_init(&stdin_buffer); 1338 buffer_init(&stdout_buffer); 1339 buffer_init(&stderr_buffer); 1340 1341 client_init_dispatch(); 1342 1343 /* 1344 * Set signal handlers, (e.g. to restore non-blocking mode) 1345 * but don't overwrite SIG_IGN, matches behaviour from rsh(1) 1346 */ 1347 if (signal(SIGHUP, SIG_IGN) != SIG_IGN) 1348 signal(SIGHUP, signal_handler); 1349 if (signal(SIGINT, SIG_IGN) != SIG_IGN) 1350 signal(SIGINT, signal_handler); 1351 if (signal(SIGQUIT, SIG_IGN) != SIG_IGN) 1352 signal(SIGQUIT, signal_handler); 1353 if (signal(SIGTERM, SIG_IGN) != SIG_IGN) 1354 signal(SIGTERM, signal_handler); 1355 signal(SIGWINCH, window_change_handler); 1356 1357 if (have_pty) 1358 enter_raw_mode(); 1359 1360 if (compat20) { 1361 session_ident = ssh2_chan_id; 1362 if (escape_char_arg != SSH_ESCAPECHAR_NONE) 1363 channel_register_filter(session_ident, 1364 client_simple_escape_filter, NULL, 1365 client_filter_cleanup, 1366 client_new_escape_filter_ctx(escape_char_arg)); 1367 if (session_ident != -1) 1368 channel_register_cleanup(session_ident, 1369 client_channel_closed, 0); 1370 } else { 1371 /* Check if we should immediately send eof on stdin. */ 1372 client_check_initial_eof_on_stdin(); 1373 } 1374 1375 /* Main loop of the client for the interactive session mode. */ 1376 while (!quit_pending) { 1377 1378 /* Process buffered packets sent by the server. */ 1379 client_process_buffered_input_packets(); 1380 1381 if (compat20 && session_closed && !channel_still_open()) 1382 break; 1383 1384 rekeying = (xxx_kex != NULL && !xxx_kex->done); 1385 1386 if (rekeying) { 1387 debug("rekeying in progress"); 1388 } else { 1389 /* 1390 * Make packets of buffered stdin data, and buffer 1391 * them for sending to the server. 1392 */ 1393 if (!compat20) 1394 client_make_packets_from_stdin_data(); 1395 1396 /* 1397 * Make packets from buffered channel data, and 1398 * enqueue them for sending to the server. 1399 */ 1400 if (packet_not_very_much_data_to_write()) 1401 channel_output_poll(); 1402 1403 /* 1404 * Check if the window size has changed, and buffer a 1405 * message about it to the server if so. 1406 */ 1407 client_check_window_change(); 1408 1409 if (quit_pending) 1410 break; 1411 } 1412 /* 1413 * Wait until we have something to do (something becomes 1414 * available on one of the descriptors). 1415 */ 1416 max_fd2 = max_fd; 1417 client_wait_until_can_do_something(&readset, &writeset, 1418 &max_fd2, &nalloc, rekeying); 1419 1420 if (quit_pending) 1421 break; 1422 1423 /* Do channel operations unless rekeying in progress. */ 1424 if (!rekeying) { 1425 channel_after_select(readset, writeset); 1426 if (need_rekeying || packet_need_rekeying()) { 1427 debug("need rekeying"); 1428 xxx_kex->done = 0; 1429 kex_send_kexinit(xxx_kex); 1430 need_rekeying = 0; 1431 } 1432 } 1433 1434 /* Buffer input from the connection. */ 1435 client_process_net_input(readset); 1436 1437 /* Accept control connections. */ 1438 if (muxserver_sock != -1 &&FD_ISSET(muxserver_sock, readset)) { 1439 if (muxserver_accept_control()) 1440 quit_pending = 1; 1441 } 1442 1443 if (quit_pending) 1444 break; 1445 1446 if (!compat20) { 1447 /* Buffer data from stdin */ 1448 client_process_input(readset); 1449 /* 1450 * Process output to stdout and stderr. Output to 1451 * the connection is processed elsewhere (above). 1452 */ 1453 client_process_output(writeset); 1454 } 1455 1456 /* 1457 * Send as much buffered packet data as possible to the 1458 * sender. 1459 */ 1460 if (FD_ISSET(connection_out, writeset)) 1461 packet_write_poll(); 1462 } 1463 if (readset) 1464 xfree(readset); 1465 if (writeset) 1466 xfree(writeset); 1467 1468 /* Terminate the session. */ 1469 1470 /* Stop watching for window change. */ 1471 signal(SIGWINCH, SIG_DFL); 1472 1473 channel_free_all(); 1474 1475 if (have_pty) 1476 leave_raw_mode(); 1477 1478 /* restore blocking io */ 1479 if (!isatty(fileno(stdin))) 1480 unset_nonblock(fileno(stdin)); 1481 if (!isatty(fileno(stdout))) 1482 unset_nonblock(fileno(stdout)); 1483 if (!isatty(fileno(stderr))) 1484 unset_nonblock(fileno(stderr)); 1485 1486 /* 1487 * If there was no shell or command requested, there will be no remote 1488 * exit status to be returned. In that case, clear error code if the 1489 * connection was deliberately terminated at this end. 1490 */ 1491 if (no_shell_flag && received_signal == SIGTERM) { 1492 received_signal = 0; 1493 exit_status = 0; 1494 } 1495 1496 if (received_signal) 1497 fatal("Killed by signal %d.", (int) received_signal); 1498 1499 /* 1500 * In interactive mode (with pseudo tty) display a message indicating 1501 * that the connection has been closed. 1502 */ 1503 if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) { 1504 snprintf(buf, sizeof buf, 1505 "Connection to %.64s closed.\r\n", host); 1506 buffer_append(&stderr_buffer, buf, strlen(buf)); 1507 } 1508 1509 /* Output any buffered data for stdout. */ 1510 while (buffer_len(&stdout_buffer) > 0) { 1511 len = write(fileno(stdout), buffer_ptr(&stdout_buffer), 1512 buffer_len(&stdout_buffer)); 1513 if (len <= 0) { 1514 error("Write failed flushing stdout buffer."); 1515 break; 1516 } 1517 buffer_consume(&stdout_buffer, len); 1518 } 1519 1520 /* Output any buffered data for stderr. */ 1521 while (buffer_len(&stderr_buffer) > 0) { 1522 len = write(fileno(stderr), buffer_ptr(&stderr_buffer), 1523 buffer_len(&stderr_buffer)); 1524 if (len <= 0) { 1525 error("Write failed flushing stderr buffer."); 1526 break; 1527 } 1528 buffer_consume(&stderr_buffer, len); 1529 } 1530 1531 /* Clear and free any buffers. */ 1532 memset(buf, 0, sizeof(buf)); 1533 buffer_free(&stdin_buffer); 1534 buffer_free(&stdout_buffer); 1535 buffer_free(&stderr_buffer); 1536 1537 /* Report bytes transferred, and transfer rates. */ 1538 total_time = get_current_time() - start_time; 1539 packet_get_state(MODE_IN, NULL, NULL, NULL, &ibytes); 1540 packet_get_state(MODE_OUT, NULL, NULL, NULL, &obytes); 1541 verbose("Transferred: sent %llu, received %llu bytes, in %.1f seconds", 1542 obytes, ibytes, total_time); 1543 if (total_time > 0) 1544 verbose("Bytes per second: sent %.1f, received %.1f", 1545 obytes / total_time, ibytes / total_time); 1546 /* Return the exit status of the program. */ 1547 debug("Exit status %d", exit_status); 1548 return exit_status; 1549 } 1550 1551 /*********/ 1552 1553 static void 1554 client_input_stdout_data(int type, u_int32_t seq, void *ctxt) 1555 { 1556 u_int data_len; 1557 char *data = packet_get_string(&data_len); 1558 packet_check_eom(); 1559 buffer_append(&stdout_buffer, data, data_len); 1560 memset(data, 0, data_len); 1561 xfree(data); 1562 } 1563 static void 1564 client_input_stderr_data(int type, u_int32_t seq, void *ctxt) 1565 { 1566 u_int data_len; 1567 char *data = packet_get_string(&data_len); 1568 packet_check_eom(); 1569 buffer_append(&stderr_buffer, data, data_len); 1570 memset(data, 0, data_len); 1571 xfree(data); 1572 } 1573 static void 1574 client_input_exit_status(int type, u_int32_t seq, void *ctxt) 1575 { 1576 exit_status = packet_get_int(); 1577 packet_check_eom(); 1578 /* Acknowledge the exit. */ 1579 packet_start(SSH_CMSG_EXIT_CONFIRMATION); 1580 packet_send(); 1581 /* 1582 * Must wait for packet to be sent since we are 1583 * exiting the loop. 1584 */ 1585 packet_write_wait(); 1586 /* Flag that we want to exit. */ 1587 quit_pending = 1; 1588 } 1589 static void 1590 client_input_agent_open(int type, u_int32_t seq, void *ctxt) 1591 { 1592 Channel *c = NULL; 1593 int remote_id, sock; 1594 1595 /* Read the remote channel number from the message. */ 1596 remote_id = packet_get_int(); 1597 packet_check_eom(); 1598 1599 /* 1600 * Get a connection to the local authentication agent (this may again 1601 * get forwarded). 1602 */ 1603 sock = ssh_get_authentication_socket(); 1604 1605 /* 1606 * If we could not connect the agent, send an error message back to 1607 * the server. This should never happen unless the agent dies, 1608 * because authentication forwarding is only enabled if we have an 1609 * agent. 1610 */ 1611 if (sock >= 0) { 1612 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock, 1613 -1, 0, 0, 0, "authentication agent connection", 1); 1614 c->remote_id = remote_id; 1615 c->force_drain = 1; 1616 } 1617 if (c == NULL) { 1618 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 1619 packet_put_int(remote_id); 1620 } else { 1621 /* Send a confirmation to the remote host. */ 1622 debug("Forwarding authentication connection."); 1623 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); 1624 packet_put_int(remote_id); 1625 packet_put_int(c->self); 1626 } 1627 packet_send(); 1628 } 1629 1630 static Channel * 1631 client_request_forwarded_tcpip(const char *request_type, int rchan) 1632 { 1633 Channel *c = NULL; 1634 char *listen_address, *originator_address; 1635 int listen_port, originator_port; 1636 1637 /* Get rest of the packet */ 1638 listen_address = packet_get_string(NULL); 1639 listen_port = packet_get_int(); 1640 originator_address = packet_get_string(NULL); 1641 originator_port = packet_get_int(); 1642 packet_check_eom(); 1643 1644 debug("client_request_forwarded_tcpip: listen %s port %d, " 1645 "originator %s port %d", listen_address, listen_port, 1646 originator_address, originator_port); 1647 1648 c = channel_connect_by_listen_address(listen_port, 1649 "forwarded-tcpip", originator_address); 1650 1651 xfree(originator_address); 1652 xfree(listen_address); 1653 return c; 1654 } 1655 1656 static Channel * 1657 client_request_x11(const char *request_type, int rchan) 1658 { 1659 Channel *c = NULL; 1660 char *originator; 1661 int originator_port; 1662 int sock; 1663 1664 if (!options.forward_x11) { 1665 error("Warning: ssh server tried X11 forwarding."); 1666 error("Warning: this is probably a break-in attempt by a " 1667 "malicious server."); 1668 return NULL; 1669 } 1670 originator = packet_get_string(NULL); 1671 if (datafellows & SSH_BUG_X11FWD) { 1672 debug2("buggy server: x11 request w/o originator_port"); 1673 originator_port = 0; 1674 } else { 1675 originator_port = packet_get_int(); 1676 } 1677 packet_check_eom(); 1678 /* XXX check permission */ 1679 debug("client_request_x11: request from %s %d", originator, 1680 originator_port); 1681 xfree(originator); 1682 sock = x11_connect_display(); 1683 if (sock < 0) 1684 return NULL; 1685 c = channel_new("x11", 1686 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1687 CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); 1688 c->force_drain = 1; 1689 return c; 1690 } 1691 1692 static Channel * 1693 client_request_agent(const char *request_type, int rchan) 1694 { 1695 Channel *c = NULL; 1696 int sock; 1697 1698 if (!options.forward_agent) { 1699 error("Warning: ssh server tried agent forwarding."); 1700 error("Warning: this is probably a break-in attempt by a " 1701 "malicious server."); 1702 return NULL; 1703 } 1704 sock = ssh_get_authentication_socket(); 1705 if (sock < 0) 1706 return NULL; 1707 c = channel_new("authentication agent connection", 1708 SSH_CHANNEL_OPEN, sock, sock, -1, 1709 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, 1710 "authentication agent connection", 1); 1711 c->force_drain = 1; 1712 return c; 1713 } 1714 1715 int 1716 client_request_tun_fwd(int tun_mode, int local_tun, int remote_tun) 1717 { 1718 Channel *c; 1719 int fd; 1720 1721 if (tun_mode == SSH_TUNMODE_NO) 1722 return 0; 1723 1724 if (!compat20) { 1725 error("Tunnel forwarding is not support for protocol 1"); 1726 return -1; 1727 } 1728 1729 debug("Requesting tun unit %d in mode %d", local_tun, tun_mode); 1730 1731 /* Open local tunnel device */ 1732 if ((fd = tun_open(local_tun, tun_mode)) == -1) { 1733 error("Tunnel device open failed."); 1734 return -1; 1735 } 1736 1737 c = channel_new("tun", SSH_CHANNEL_OPENING, fd, fd, -1, 1738 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1); 1739 c->datagram = 1; 1740 1741 #if defined(SSH_TUN_FILTER) 1742 if (options.tun_open == SSH_TUNMODE_POINTOPOINT) 1743 channel_register_filter(c->self, sys_tun_infilter, 1744 sys_tun_outfilter, NULL, NULL); 1745 #endif 1746 1747 packet_start(SSH2_MSG_CHANNEL_OPEN); 1748 packet_put_cstring("tun@openssh.com"); 1749 packet_put_int(c->self); 1750 packet_put_int(c->local_window_max); 1751 packet_put_int(c->local_maxpacket); 1752 packet_put_int(tun_mode); 1753 packet_put_int(remote_tun); 1754 packet_send(); 1755 1756 return 0; 1757 } 1758 1759 /* XXXX move to generic input handler */ 1760 static void 1761 client_input_channel_open(int type, u_int32_t seq, void *ctxt) 1762 { 1763 Channel *c = NULL; 1764 char *ctype; 1765 int rchan; 1766 u_int rmaxpack, rwindow, len; 1767 1768 ctype = packet_get_string(&len); 1769 rchan = packet_get_int(); 1770 rwindow = packet_get_int(); 1771 rmaxpack = packet_get_int(); 1772 1773 debug("client_input_channel_open: ctype %s rchan %d win %d max %d", 1774 ctype, rchan, rwindow, rmaxpack); 1775 1776 if (strcmp(ctype, "forwarded-tcpip") == 0) { 1777 c = client_request_forwarded_tcpip(ctype, rchan); 1778 } else if (strcmp(ctype, "x11") == 0) { 1779 c = client_request_x11(ctype, rchan); 1780 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) { 1781 c = client_request_agent(ctype, rchan); 1782 } 1783 /* XXX duplicate : */ 1784 if (c != NULL) { 1785 debug("confirm %s", ctype); 1786 c->remote_id = rchan; 1787 c->remote_window = rwindow; 1788 c->remote_maxpacket = rmaxpack; 1789 if (c->type != SSH_CHANNEL_CONNECTING) { 1790 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); 1791 packet_put_int(c->remote_id); 1792 packet_put_int(c->self); 1793 packet_put_int(c->local_window); 1794 packet_put_int(c->local_maxpacket); 1795 packet_send(); 1796 } 1797 } else { 1798 debug("failure %s", ctype); 1799 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); 1800 packet_put_int(rchan); 1801 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED); 1802 if (!(datafellows & SSH_BUG_OPENFAILURE)) { 1803 packet_put_cstring("open failed"); 1804 packet_put_cstring(""); 1805 } 1806 packet_send(); 1807 } 1808 xfree(ctype); 1809 } 1810 static void 1811 client_input_channel_req(int type, u_int32_t seq, void *ctxt) 1812 { 1813 Channel *c = NULL; 1814 int exitval, id, reply, success = 0; 1815 char *rtype; 1816 1817 id = packet_get_int(); 1818 rtype = packet_get_string(NULL); 1819 reply = packet_get_char(); 1820 1821 debug("client_input_channel_req: channel %d rtype %s reply %d", 1822 id, rtype, reply); 1823 1824 if (id == -1) { 1825 error("client_input_channel_req: request for channel -1"); 1826 } else if ((c = channel_lookup(id)) == NULL) { 1827 error("client_input_channel_req: channel %d: " 1828 "unknown channel", id); 1829 } else if (strcmp(rtype, "eow@openssh.com") == 0) { 1830 packet_check_eom(); 1831 chan_rcvd_eow(c); 1832 } else if (strcmp(rtype, "exit-status") == 0) { 1833 exitval = packet_get_int(); 1834 if (id == session_ident) { 1835 success = 1; 1836 exit_status = exitval; 1837 } else if (c->ctl_fd == -1) { 1838 error("client_input_channel_req: unexpected channel %d", 1839 session_ident); 1840 } else { 1841 atomicio(vwrite, c->ctl_fd, &exitval, sizeof(exitval)); 1842 success = 1; 1843 } 1844 packet_check_eom(); 1845 } 1846 if (reply) { 1847 packet_start(success ? 1848 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE); 1849 packet_put_int(id); 1850 packet_send(); 1851 } 1852 xfree(rtype); 1853 } 1854 static void 1855 client_input_global_request(int type, u_int32_t seq, void *ctxt) 1856 { 1857 char *rtype; 1858 int want_reply; 1859 int success = 0; 1860 1861 rtype = packet_get_string(NULL); 1862 want_reply = packet_get_char(); 1863 debug("client_input_global_request: rtype %s want_reply %d", 1864 rtype, want_reply); 1865 if (want_reply) { 1866 packet_start(success ? 1867 SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE); 1868 packet_send(); 1869 packet_write_wait(); 1870 } 1871 xfree(rtype); 1872 } 1873 1874 void 1875 client_session2_setup(int id, int want_tty, int want_subsystem, 1876 const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env) 1877 { 1878 int len; 1879 Channel *c = NULL; 1880 1881 debug2("%s: id %d", __func__, id); 1882 1883 if ((c = channel_lookup(id)) == NULL) 1884 fatal("client_session2_setup: channel %d: unknown channel", id); 1885 1886 if (want_tty) { 1887 struct winsize ws; 1888 1889 /* Store window size in the packet. */ 1890 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0) 1891 memset(&ws, 0, sizeof(ws)); 1892 1893 channel_request_start(id, "pty-req", 1); 1894 client_expect_confirm(id, "PTY allocation", 0); 1895 packet_put_cstring(term != NULL ? term : ""); 1896 packet_put_int((u_int)ws.ws_col); 1897 packet_put_int((u_int)ws.ws_row); 1898 packet_put_int((u_int)ws.ws_xpixel); 1899 packet_put_int((u_int)ws.ws_ypixel); 1900 if (tiop == NULL) 1901 tiop = get_saved_tio(); 1902 tty_make_modes(-1, tiop); 1903 packet_send(); 1904 /* XXX wait for reply */ 1905 c->client_tty = 1; 1906 } 1907 1908 /* Transfer any environment variables from client to server */ 1909 if (options.num_send_env != 0 && env != NULL) { 1910 int i, j, matched; 1911 char *name, *val; 1912 1913 debug("Sending environment."); 1914 for (i = 0; env[i] != NULL; i++) { 1915 /* Split */ 1916 name = xstrdup(env[i]); 1917 if ((val = strchr(name, '=')) == NULL) { 1918 xfree(name); 1919 continue; 1920 } 1921 *val++ = '\0'; 1922 1923 matched = 0; 1924 for (j = 0; j < options.num_send_env; j++) { 1925 if (match_pattern(name, options.send_env[j])) { 1926 matched = 1; 1927 break; 1928 } 1929 } 1930 if (!matched) { 1931 debug3("Ignored env %s", name); 1932 xfree(name); 1933 continue; 1934 } 1935 1936 debug("Sending env %s = %s", name, val); 1937 channel_request_start(id, "env", 0); 1938 packet_put_cstring(name); 1939 packet_put_cstring(val); 1940 packet_send(); 1941 xfree(name); 1942 } 1943 } 1944 1945 len = buffer_len(cmd); 1946 if (len > 0) { 1947 if (len > 900) 1948 len = 900; 1949 if (want_subsystem) { 1950 debug("Sending subsystem: %.*s", 1951 len, (u_char*)buffer_ptr(cmd)); 1952 channel_request_start(id, "subsystem", 1); 1953 client_expect_confirm(id, "subsystem", 1); 1954 } else { 1955 debug("Sending command: %.*s", 1956 len, (u_char*)buffer_ptr(cmd)); 1957 channel_request_start(id, "exec", 1); 1958 client_expect_confirm(id, "exec", 1); 1959 } 1960 packet_put_string(buffer_ptr(cmd), buffer_len(cmd)); 1961 packet_send(); 1962 } else { 1963 channel_request_start(id, "shell", 1); 1964 client_expect_confirm(id, "shell", 1); 1965 packet_send(); 1966 } 1967 } 1968 1969 static void 1970 client_init_dispatch_20(void) 1971 { 1972 dispatch_init(&dispatch_protocol_error); 1973 1974 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); 1975 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); 1976 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); 1977 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); 1978 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open); 1979 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 1980 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 1981 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req); 1982 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); 1983 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm); 1984 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm); 1985 dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request); 1986 1987 /* rekeying */ 1988 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); 1989 1990 /* global request reply messages */ 1991 dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply); 1992 dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply); 1993 } 1994 1995 static void 1996 client_init_dispatch_13(void) 1997 { 1998 dispatch_init(NULL); 1999 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close); 2000 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation); 2001 dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data); 2002 dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 2003 dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 2004 dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open); 2005 dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status); 2006 dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data); 2007 dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data); 2008 2009 dispatch_set(SSH_SMSG_AGENT_OPEN, options.forward_agent ? 2010 &client_input_agent_open : &deny_input_open); 2011 dispatch_set(SSH_SMSG_X11_OPEN, options.forward_x11 ? 2012 &x11_input_open : &deny_input_open); 2013 } 2014 2015 static void 2016 client_init_dispatch_15(void) 2017 { 2018 client_init_dispatch_13(); 2019 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof); 2020 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose); 2021 } 2022 2023 static void 2024 client_init_dispatch(void) 2025 { 2026 if (compat20) 2027 client_init_dispatch_20(); 2028 else if (compat13) 2029 client_init_dispatch_13(); 2030 else 2031 client_init_dispatch_15(); 2032 } 2033 2034 /* client specific fatal cleanup */ 2035 void 2036 cleanup_exit(int i) 2037 { 2038 leave_raw_mode(); 2039 leave_non_blocking(); 2040 if (options.control_path != NULL && muxserver_sock != -1) 2041 unlink(options.control_path); 2042 _exit(i); 2043 } 2044