1 /* $OpenBSD: clientloop.c,v 1.215 2009/11/17 05:31:44 djm Exp $ */ 2 /* 3 * Author: Tatu Ylonen <ylo@cs.hut.fi> 4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 5 * All rights reserved 6 * The main loop for the interactive session (client side). 7 * 8 * As far as I am concerned, the code I have written for this software 9 * can be used freely for any purpose. Any derived versions of this 10 * software must be clearly marked as such, and if the derived work is 11 * incompatible with the protocol description in the RFC file, it must be 12 * called by a name other than "ssh" or "Secure Shell". 13 * 14 * 15 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 16 * 17 * Redistribution and use in source and binary forms, with or without 18 * modification, are permitted provided that the following conditions 19 * are met: 20 * 1. Redistributions of source code must retain the above copyright 21 * notice, this list of conditions and the following disclaimer. 22 * 2. Redistributions in binary form must reproduce the above copyright 23 * notice, this list of conditions and the following disclaimer in the 24 * documentation and/or other materials provided with the distribution. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 27 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 28 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 29 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 30 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 31 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 35 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 36 * 37 * 38 * SSH2 support added by Markus Friedl. 39 * Copyright (c) 1999, 2000, 2001 Markus Friedl. All rights reserved. 40 * 41 * Redistribution and use in source and binary forms, with or without 42 * modification, are permitted provided that the following conditions 43 * are met: 44 * 1. Redistributions of source code must retain the above copyright 45 * notice, this list of conditions and the following disclaimer. 46 * 2. Redistributions in binary form must reproduce the above copyright 47 * notice, this list of conditions and the following disclaimer in the 48 * documentation and/or other materials provided with the distribution. 49 * 50 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 51 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 52 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 53 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 54 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 55 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 56 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 57 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 58 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 59 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 60 */ 61 62 63 #include <sys/types.h> 64 #include <sys/ioctl.h> 65 #include <sys/stat.h> 66 #include <sys/socket.h> 67 #include <sys/time.h> 68 #include <sys/param.h> 69 #include <sys/queue.h> 70 71 #include <ctype.h> 72 #include <errno.h> 73 #include <paths.h> 74 #include <signal.h> 75 #include <stdio.h> 76 #include <stdlib.h> 77 #include <string.h> 78 #include <termios.h> 79 #include <pwd.h> 80 #include <unistd.h> 81 82 #include "xmalloc.h" 83 #include "ssh.h" 84 #include "ssh1.h" 85 #include "ssh2.h" 86 #include "packet.h" 87 #include "buffer.h" 88 #include "compat.h" 89 #include "channels.h" 90 #include "dispatch.h" 91 #include "key.h" 92 #include "cipher.h" 93 #include "kex.h" 94 #include "log.h" 95 #include "readconf.h" 96 #include "clientloop.h" 97 #include "sshconnect.h" 98 #include "authfd.h" 99 #include "atomicio.h" 100 #include "sshpty.h" 101 #include "misc.h" 102 #include "match.h" 103 #include "msg.h" 104 #include "roaming.h" 105 106 /* import options */ 107 extern Options options; 108 109 /* Flag indicating that stdin should be redirected from /dev/null. */ 110 extern int stdin_null_flag; 111 112 /* Flag indicating that no shell has been requested */ 113 extern int no_shell_flag; 114 115 /* Control socket */ 116 extern int muxserver_sock; 117 118 /* 119 * Name of the host we are connecting to. This is the name given on the 120 * command line, or the HostName specified for the user-supplied name in a 121 * configuration file. 122 */ 123 extern char *host; 124 125 /* 126 * Flag to indicate that we have received a window change signal which has 127 * not yet been processed. This will cause a message indicating the new 128 * window size to be sent to the server a little later. This is volatile 129 * because this is updated in a signal handler. 130 */ 131 static volatile sig_atomic_t received_window_change_signal = 0; 132 static volatile sig_atomic_t received_signal = 0; 133 134 /* Flag indicating whether the user's terminal is in non-blocking mode. */ 135 static int in_non_blocking_mode = 0; 136 137 /* Common data for the client loop code. */ 138 static volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */ 139 static int escape_char1; /* Escape character. (proto1 only) */ 140 static int escape_pending1; /* Last character was an escape (proto1 only) */ 141 static int last_was_cr; /* Last character was a newline. */ 142 static int exit_status; /* Used to store the command exit status. */ 143 static int stdin_eof; /* EOF has been encountered on stderr. */ 144 static Buffer stdin_buffer; /* Buffer for stdin data. */ 145 static Buffer stdout_buffer; /* Buffer for stdout data. */ 146 static Buffer stderr_buffer; /* Buffer for stderr data. */ 147 static u_int buffer_high;/* Soft max buffer size. */ 148 static int connection_in; /* Connection to server (input). */ 149 static int connection_out; /* Connection to server (output). */ 150 static int need_rekeying; /* Set to non-zero if rekeying is requested. */ 151 static int session_closed = 0; /* In SSH2: login session closed. */ 152 153 static void client_init_dispatch(void); 154 int session_ident = -1; 155 156 int session_resumed = 0; 157 158 /* Track escape per proto2 channel */ 159 struct escape_filter_ctx { 160 int escape_pending; 161 int escape_char; 162 }; 163 164 /* Context for channel confirmation replies */ 165 struct channel_reply_ctx { 166 const char *request_type; 167 int id, do_close; 168 }; 169 170 /* Global request success/failure callbacks */ 171 struct global_confirm { 172 TAILQ_ENTRY(global_confirm) entry; 173 global_confirm_cb *cb; 174 void *ctx; 175 int ref_count; 176 }; 177 TAILQ_HEAD(global_confirms, global_confirm); 178 static struct global_confirms global_confirms = 179 TAILQ_HEAD_INITIALIZER(global_confirms); 180 181 /*XXX*/ 182 extern Kex *xxx_kex; 183 184 void ssh_process_session2_setup(int, int, int, Buffer *); 185 186 /* Restores stdin to blocking mode. */ 187 188 static void 189 leave_non_blocking(void) 190 { 191 if (in_non_blocking_mode) { 192 unset_nonblock(fileno(stdin)); 193 in_non_blocking_mode = 0; 194 } 195 } 196 197 /* Puts stdin terminal in non-blocking mode. */ 198 199 static void 200 enter_non_blocking(void) 201 { 202 in_non_blocking_mode = 1; 203 set_nonblock(fileno(stdin)); 204 } 205 206 /* 207 * Signal handler for the window change signal (SIGWINCH). This just sets a 208 * flag indicating that the window has changed. 209 */ 210 /*ARGSUSED */ 211 static void 212 window_change_handler(int sig) 213 { 214 received_window_change_signal = 1; 215 signal(SIGWINCH, window_change_handler); 216 } 217 218 /* 219 * Signal handler for signals that cause the program to terminate. These 220 * signals must be trapped to restore terminal modes. 221 */ 222 /*ARGSUSED */ 223 static void 224 signal_handler(int sig) 225 { 226 received_signal = sig; 227 quit_pending = 1; 228 } 229 230 /* 231 * Returns current time in seconds from Jan 1, 1970 with the maximum 232 * available resolution. 233 */ 234 235 static double 236 get_current_time(void) 237 { 238 struct timeval tv; 239 gettimeofday(&tv, NULL); 240 return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0; 241 } 242 243 #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1" 244 void 245 client_x11_get_proto(const char *display, const char *xauth_path, 246 u_int trusted, char **_proto, char **_data) 247 { 248 char cmd[1024]; 249 char line[512]; 250 char xdisplay[512]; 251 static char proto[512], data[512]; 252 FILE *f; 253 int got_data = 0, generated = 0, do_unlink = 0, i; 254 char *xauthdir, *xauthfile; 255 struct stat st; 256 257 xauthdir = xauthfile = NULL; 258 *_proto = proto; 259 *_data = data; 260 proto[0] = data[0] = '\0'; 261 262 if (xauth_path == NULL ||(stat(xauth_path, &st) == -1)) { 263 debug("No xauth program."); 264 } else { 265 if (display == NULL) { 266 debug("x11_get_proto: DISPLAY not set"); 267 return; 268 } 269 /* 270 * Handle FamilyLocal case where $DISPLAY does 271 * not match an authorization entry. For this we 272 * just try "xauth list unix:displaynum.screennum". 273 * XXX: "localhost" match to determine FamilyLocal 274 * is not perfect. 275 */ 276 if (strncmp(display, "localhost:", 10) == 0) { 277 snprintf(xdisplay, sizeof(xdisplay), "unix:%s", 278 display + 10); 279 display = xdisplay; 280 } 281 if (trusted == 0) { 282 xauthdir = xmalloc(MAXPATHLEN); 283 xauthfile = xmalloc(MAXPATHLEN); 284 strlcpy(xauthdir, "/tmp/ssh-XXXXXXXXXX", MAXPATHLEN); 285 if (mkdtemp(xauthdir) != NULL) { 286 do_unlink = 1; 287 snprintf(xauthfile, MAXPATHLEN, "%s/xauthfile", 288 xauthdir); 289 snprintf(cmd, sizeof(cmd), 290 "%s -f %s generate %s " SSH_X11_PROTO 291 " untrusted timeout 1200 2>" _PATH_DEVNULL, 292 xauth_path, xauthfile, display); 293 debug2("x11_get_proto: %s", cmd); 294 if (system(cmd) == 0) 295 generated = 1; 296 } 297 } 298 299 /* 300 * When in untrusted mode, we read the cookie only if it was 301 * successfully generated as an untrusted one in the step 302 * above. 303 */ 304 if (trusted || generated) { 305 snprintf(cmd, sizeof(cmd), 306 "%s %s%s list %s 2>" _PATH_DEVNULL, 307 xauth_path, 308 generated ? "-f " : "" , 309 generated ? xauthfile : "", 310 display); 311 debug2("x11_get_proto: %s", cmd); 312 f = popen(cmd, "r"); 313 if (f && fgets(line, sizeof(line), f) && 314 sscanf(line, "%*s %511s %511s", proto, data) == 2) 315 got_data = 1; 316 if (f) 317 pclose(f); 318 } else 319 error("Warning: untrusted X11 forwarding setup failed: " 320 "xauth key data not generated"); 321 } 322 323 if (do_unlink) { 324 unlink(xauthfile); 325 rmdir(xauthdir); 326 } 327 if (xauthdir) 328 xfree(xauthdir); 329 if (xauthfile) 330 xfree(xauthfile); 331 332 /* 333 * If we didn't get authentication data, just make up some 334 * data. The forwarding code will check the validity of the 335 * response anyway, and substitute this data. The X11 336 * server, however, will ignore this fake data and use 337 * whatever authentication mechanisms it was using otherwise 338 * for the local connection. 339 */ 340 if (!got_data) { 341 u_int32_t rnd = 0; 342 343 logit("Warning: No xauth data; " 344 "using fake authentication data for X11 forwarding."); 345 strlcpy(proto, SSH_X11_PROTO, sizeof proto); 346 for (i = 0; i < 16; i++) { 347 if (i % 4 == 0) 348 rnd = arc4random(); 349 snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", 350 rnd & 0xff); 351 rnd >>= 8; 352 } 353 } 354 } 355 356 /* 357 * This is called when the interactive is entered. This checks if there is 358 * an EOF coming on stdin. We must check this explicitly, as select() does 359 * not appear to wake up when redirecting from /dev/null. 360 */ 361 362 static void 363 client_check_initial_eof_on_stdin(void) 364 { 365 int len; 366 char buf[1]; 367 368 /* 369 * If standard input is to be "redirected from /dev/null", we simply 370 * mark that we have seen an EOF and send an EOF message to the 371 * server. Otherwise, we try to read a single character; it appears 372 * that for some files, such /dev/null, select() never wakes up for 373 * read for this descriptor, which means that we never get EOF. This 374 * way we will get the EOF if stdin comes from /dev/null or similar. 375 */ 376 if (stdin_null_flag) { 377 /* Fake EOF on stdin. */ 378 debug("Sending eof."); 379 stdin_eof = 1; 380 packet_start(SSH_CMSG_EOF); 381 packet_send(); 382 } else { 383 enter_non_blocking(); 384 385 /* Check for immediate EOF on stdin. */ 386 len = read(fileno(stdin), buf, 1); 387 if (len == 0) { 388 /* 389 * EOF. Record that we have seen it and send 390 * EOF to server. 391 */ 392 debug("Sending eof."); 393 stdin_eof = 1; 394 packet_start(SSH_CMSG_EOF); 395 packet_send(); 396 } else if (len > 0) { 397 /* 398 * Got data. We must store the data in the buffer, 399 * and also process it as an escape character if 400 * appropriate. 401 */ 402 if ((u_char) buf[0] == escape_char1) 403 escape_pending1 = 1; 404 else 405 buffer_append(&stdin_buffer, buf, 1); 406 } 407 leave_non_blocking(); 408 } 409 } 410 411 412 /* 413 * Make packets from buffered stdin data, and buffer them for sending to the 414 * connection. 415 */ 416 417 static void 418 client_make_packets_from_stdin_data(void) 419 { 420 u_int len; 421 422 /* Send buffered stdin data to the server. */ 423 while (buffer_len(&stdin_buffer) > 0 && 424 packet_not_very_much_data_to_write()) { 425 len = buffer_len(&stdin_buffer); 426 /* Keep the packets at reasonable size. */ 427 if (len > packet_get_maxsize()) 428 len = packet_get_maxsize(); 429 packet_start(SSH_CMSG_STDIN_DATA); 430 packet_put_string(buffer_ptr(&stdin_buffer), len); 431 packet_send(); 432 buffer_consume(&stdin_buffer, len); 433 /* If we have a pending EOF, send it now. */ 434 if (stdin_eof && buffer_len(&stdin_buffer) == 0) { 435 packet_start(SSH_CMSG_EOF); 436 packet_send(); 437 } 438 } 439 } 440 441 /* 442 * Checks if the client window has changed, and sends a packet about it to 443 * the server if so. The actual change is detected elsewhere (by a software 444 * interrupt on Unix); this just checks the flag and sends a message if 445 * appropriate. 446 */ 447 448 static void 449 client_check_window_change(void) 450 { 451 struct winsize ws; 452 453 if (! received_window_change_signal) 454 return; 455 /** XXX race */ 456 received_window_change_signal = 0; 457 458 debug2("client_check_window_change: changed"); 459 460 if (compat20) { 461 channel_send_window_changes(); 462 } else { 463 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) 464 return; 465 packet_start(SSH_CMSG_WINDOW_SIZE); 466 packet_put_int((u_int)ws.ws_row); 467 packet_put_int((u_int)ws.ws_col); 468 packet_put_int((u_int)ws.ws_xpixel); 469 packet_put_int((u_int)ws.ws_ypixel); 470 packet_send(); 471 } 472 } 473 474 static void 475 client_global_request_reply(int type, u_int32_t seq, void *ctxt) 476 { 477 struct global_confirm *gc; 478 479 if ((gc = TAILQ_FIRST(&global_confirms)) == NULL) 480 return; 481 if (gc->cb != NULL) 482 gc->cb(type, seq, gc->ctx); 483 if (--gc->ref_count <= 0) { 484 TAILQ_REMOVE(&global_confirms, gc, entry); 485 bzero(gc, sizeof(*gc)); 486 xfree(gc); 487 } 488 489 packet_set_alive_timeouts(0); 490 } 491 492 static void 493 server_alive_check(void) 494 { 495 if (packet_inc_alive_timeouts() > options.server_alive_count_max) { 496 logit("Timeout, server not responding."); 497 cleanup_exit(255); 498 } 499 packet_start(SSH2_MSG_GLOBAL_REQUEST); 500 packet_put_cstring("keepalive@openssh.com"); 501 packet_put_char(1); /* boolean: want reply */ 502 packet_send(); 503 /* Insert an empty placeholder to maintain ordering */ 504 client_register_global_confirm(NULL, NULL); 505 } 506 507 /* 508 * Waits until the client can do something (some data becomes available on 509 * one of the file descriptors). 510 */ 511 static void 512 client_wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, 513 int *maxfdp, u_int *nallocp, int rekeying) 514 { 515 struct timeval tv, *tvp; 516 int ret; 517 518 /* Add any selections by the channel mechanism. */ 519 channel_prepare_select(readsetp, writesetp, maxfdp, nallocp, rekeying); 520 521 if (!compat20) { 522 /* Read from the connection, unless our buffers are full. */ 523 if (buffer_len(&stdout_buffer) < buffer_high && 524 buffer_len(&stderr_buffer) < buffer_high && 525 channel_not_very_much_buffered_data()) 526 FD_SET(connection_in, *readsetp); 527 /* 528 * Read from stdin, unless we have seen EOF or have very much 529 * buffered data to send to the server. 530 */ 531 if (!stdin_eof && packet_not_very_much_data_to_write()) 532 FD_SET(fileno(stdin), *readsetp); 533 534 /* Select stdout/stderr if have data in buffer. */ 535 if (buffer_len(&stdout_buffer) > 0) 536 FD_SET(fileno(stdout), *writesetp); 537 if (buffer_len(&stderr_buffer) > 0) 538 FD_SET(fileno(stderr), *writesetp); 539 } else { 540 /* channel_prepare_select could have closed the last channel */ 541 if (session_closed && !channel_still_open() && 542 !packet_have_data_to_write()) { 543 /* clear mask since we did not call select() */ 544 memset(*readsetp, 0, *nallocp); 545 memset(*writesetp, 0, *nallocp); 546 return; 547 } else { 548 FD_SET(connection_in, *readsetp); 549 } 550 } 551 552 /* Select server connection if have data to write to the server. */ 553 if (packet_have_data_to_write()) 554 FD_SET(connection_out, *writesetp); 555 556 if (muxserver_sock != -1) 557 FD_SET(muxserver_sock, *readsetp); 558 559 /* 560 * Wait for something to happen. This will suspend the process until 561 * some selected descriptor can be read, written, or has some other 562 * event pending. 563 */ 564 565 if (options.server_alive_interval == 0 || !compat20) 566 tvp = NULL; 567 else { 568 tv.tv_sec = options.server_alive_interval; 569 tv.tv_usec = 0; 570 tvp = &tv; 571 } 572 ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp); 573 if (ret < 0) { 574 char buf[100]; 575 576 /* 577 * We have to clear the select masks, because we return. 578 * We have to return, because the mainloop checks for the flags 579 * set by the signal handlers. 580 */ 581 memset(*readsetp, 0, *nallocp); 582 memset(*writesetp, 0, *nallocp); 583 584 if (errno == EINTR) 585 return; 586 /* Note: we might still have data in the buffers. */ 587 snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno)); 588 buffer_append(&stderr_buffer, buf, strlen(buf)); 589 quit_pending = 1; 590 } else if (ret == 0) 591 server_alive_check(); 592 } 593 594 static void 595 client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr) 596 { 597 /* Flush stdout and stderr buffers. */ 598 if (buffer_len(bout) > 0) 599 atomicio(vwrite, fileno(stdout), buffer_ptr(bout), 600 buffer_len(bout)); 601 if (buffer_len(berr) > 0) 602 atomicio(vwrite, fileno(stderr), buffer_ptr(berr), 603 buffer_len(berr)); 604 605 leave_raw_mode(); 606 607 /* 608 * Free (and clear) the buffer to reduce the amount of data that gets 609 * written to swap. 610 */ 611 buffer_free(bin); 612 buffer_free(bout); 613 buffer_free(berr); 614 615 /* Send the suspend signal to the program itself. */ 616 kill(getpid(), SIGTSTP); 617 618 /* Reset window sizes in case they have changed */ 619 received_window_change_signal = 1; 620 621 /* OK, we have been continued by the user. Reinitialize buffers. */ 622 buffer_init(bin); 623 buffer_init(bout); 624 buffer_init(berr); 625 626 enter_raw_mode(); 627 } 628 629 static void 630 client_process_net_input(fd_set *readset) 631 { 632 int len, cont = 0; 633 char buf[8192]; 634 635 /* 636 * Read input from the server, and add any such data to the buffer of 637 * the packet subsystem. 638 */ 639 if (FD_ISSET(connection_in, readset)) { 640 /* Read as much as possible. */ 641 len = roaming_read(connection_in, buf, sizeof(buf), &cont); 642 if (len == 0 && cont == 0) { 643 /* 644 * Received EOF. The remote host has closed the 645 * connection. 646 */ 647 snprintf(buf, sizeof buf, 648 "Connection to %.300s closed by remote host.\r\n", 649 host); 650 buffer_append(&stderr_buffer, buf, strlen(buf)); 651 quit_pending = 1; 652 return; 653 } 654 /* 655 * There is a kernel bug on Solaris that causes select to 656 * sometimes wake up even though there is no data available. 657 */ 658 if (len < 0 && (errno == EAGAIN || errno == EINTR)) 659 len = 0; 660 661 if (len < 0) { 662 /* 663 * An error has encountered. Perhaps there is a 664 * network problem. 665 */ 666 snprintf(buf, sizeof buf, 667 "Read from remote host %.300s: %.100s\r\n", 668 host, strerror(errno)); 669 buffer_append(&stderr_buffer, buf, strlen(buf)); 670 quit_pending = 1; 671 return; 672 } 673 packet_process_incoming(buf, len); 674 } 675 } 676 677 static void 678 client_status_confirm(int type, Channel *c, void *ctx) 679 { 680 struct channel_reply_ctx *cr = (struct channel_reply_ctx *)ctx; 681 char errmsg[256]; 682 int tochan; 683 684 /* XXX supress on mux _client_ quietmode */ 685 tochan = options.log_level >= SYSLOG_LEVEL_ERROR && 686 c->ctl_fd != -1 && c->extended_usage == CHAN_EXTENDED_WRITE; 687 688 if (type == SSH2_MSG_CHANNEL_SUCCESS) { 689 debug2("%s request accepted on channel %d", 690 cr->request_type, c->self); 691 } else if (type == SSH2_MSG_CHANNEL_FAILURE) { 692 if (tochan) { 693 snprintf(errmsg, sizeof(errmsg), 694 "%s request failed\r\n", cr->request_type); 695 } else { 696 snprintf(errmsg, sizeof(errmsg), 697 "%s request failed on channel %d", 698 cr->request_type, c->self); 699 } 700 /* If error occurred on primary session channel, then exit */ 701 if (cr->do_close && c->self == session_ident) 702 fatal("%s", errmsg); 703 /* If error occurred on mux client, append to their stderr */ 704 if (tochan) 705 buffer_append(&c->extended, errmsg, strlen(errmsg)); 706 else 707 error("%s", errmsg); 708 if (cr->do_close) { 709 chan_read_failed(c); 710 chan_write_failed(c); 711 } 712 } 713 xfree(cr); 714 } 715 716 static void 717 client_abandon_status_confirm(Channel *c, void *ctx) 718 { 719 xfree(ctx); 720 } 721 722 static void 723 client_expect_confirm(int id, const char *request, int do_close) 724 { 725 struct channel_reply_ctx *cr = xmalloc(sizeof(*cr)); 726 727 cr->request_type = request; 728 cr->do_close = do_close; 729 730 channel_register_status_confirm(id, client_status_confirm, 731 client_abandon_status_confirm, cr); 732 } 733 734 void 735 client_register_global_confirm(global_confirm_cb *cb, void *ctx) 736 { 737 struct global_confirm *gc, *last_gc; 738 739 /* Coalesce identical callbacks */ 740 last_gc = TAILQ_LAST(&global_confirms, global_confirms); 741 if (last_gc && last_gc->cb == cb && last_gc->ctx == ctx) { 742 if (++last_gc->ref_count >= INT_MAX) 743 fatal("%s: last_gc->ref_count = %d", 744 __func__, last_gc->ref_count); 745 return; 746 } 747 748 gc = xmalloc(sizeof(*gc)); 749 gc->cb = cb; 750 gc->ctx = ctx; 751 gc->ref_count = 1; 752 TAILQ_INSERT_TAIL(&global_confirms, gc, entry); 753 } 754 755 static void 756 process_cmdline(void) 757 { 758 void (*handler)(int); 759 char *s, *cmd, *cancel_host; 760 int delete = 0; 761 int local = 0, remote = 0, dynamic = 0; 762 int cancel_port; 763 Forward fwd; 764 765 bzero(&fwd, sizeof(fwd)); 766 fwd.listen_host = fwd.connect_host = NULL; 767 768 leave_raw_mode(); 769 handler = signal(SIGINT, SIG_IGN); 770 cmd = s = read_passphrase("\r\nssh> ", RP_ECHO); 771 if (s == NULL) 772 goto out; 773 while (isspace(*s)) 774 s++; 775 if (*s == '-') 776 s++; /* Skip cmdline '-', if any */ 777 if (*s == '\0') 778 goto out; 779 780 if (*s == 'h' || *s == 'H' || *s == '?') { 781 logit("Commands:"); 782 logit(" -L[bind_address:]port:host:hostport " 783 "Request local forward"); 784 logit(" -R[bind_address:]port:host:hostport " 785 "Request remote forward"); 786 logit(" -D[bind_address:]port " 787 "Request dynamic forward"); 788 logit(" -KR[bind_address:]port " 789 "Cancel remote forward"); 790 if (!options.permit_local_command) 791 goto out; 792 logit(" !args " 793 "Execute local command"); 794 goto out; 795 } 796 797 if (*s == '!' && options.permit_local_command) { 798 s++; 799 ssh_local_cmd(s); 800 goto out; 801 } 802 803 if (*s == 'K') { 804 delete = 1; 805 s++; 806 } 807 if (*s == 'L') 808 local = 1; 809 else if (*s == 'R') 810 remote = 1; 811 else if (*s == 'D') 812 dynamic = 1; 813 else { 814 logit("Invalid command."); 815 goto out; 816 } 817 818 if ((local || dynamic) && delete) { 819 logit("Not supported."); 820 goto out; 821 } 822 if (remote && 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, dynamic, remote)) { 847 logit("Bad forwarding specification."); 848 goto out; 849 } 850 if (local || dynamic) { 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 %cR - Request rekey (SSH protocol 2 only)\r\n\ 1040 %c# - list forwarded connections\r\n\ 1041 %c? - this message\r\n\ 1042 %c%c - send the escape character by typing it twice\r\n\ 1043 (Note that escapes are only recognized immediately after newline.)\r\n", 1044 escape_char, escape_char, 1045 escape_char, escape_char, 1046 escape_char, escape_char, 1047 escape_char, escape_char); 1048 } else { 1049 snprintf(string, sizeof string, 1050 "%c?\r\n\ 1051 Supported escape sequences:\r\n\ 1052 %c. - terminate connection (and any multiplexed sessions)\r\n\ 1053 %cB - send a BREAK to the remote system\r\n\ 1054 %cC - open a command line\r\n\ 1055 %cR - Request rekey (SSH protocol 2 only)\r\n\ 1056 %c^Z - suspend ssh\r\n\ 1057 %c# - list forwarded connections\r\n\ 1058 %c& - background ssh (when waiting for connections to terminate)\r\n\ 1059 %c? - this message\r\n\ 1060 %c%c - send the escape character by typing it twice\r\n\ 1061 (Note that escapes are only recognized immediately after newline.)\r\n", 1062 escape_char, escape_char, 1063 escape_char, escape_char, 1064 escape_char, escape_char, 1065 escape_char, escape_char, 1066 escape_char, escape_char, 1067 escape_char); 1068 } 1069 buffer_append(berr, string, strlen(string)); 1070 continue; 1071 1072 case '#': 1073 snprintf(string, sizeof string, "%c#\r\n", 1074 escape_char); 1075 buffer_append(berr, string, strlen(string)); 1076 s = channel_open_message(); 1077 buffer_append(berr, s, strlen(s)); 1078 xfree(s); 1079 continue; 1080 1081 case 'C': 1082 if (c && c->ctl_fd != -1) 1083 goto noescape; 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 && (errno == EAGAIN || errno == EINTR)) 1132 return; /* we'll try again later */ 1133 if (len <= 0) { 1134 /* 1135 * Received EOF or error. They are treated 1136 * similarly, except that an error message is printed 1137 * if it was an error condition. 1138 */ 1139 if (len < 0) { 1140 snprintf(buf, sizeof buf, "read: %.100s\r\n", 1141 strerror(errno)); 1142 buffer_append(&stderr_buffer, buf, strlen(buf)); 1143 } 1144 /* Mark that we have seen EOF. */ 1145 stdin_eof = 1; 1146 /* 1147 * Send an EOF message to the server unless there is 1148 * data in the buffer. If there is data in the 1149 * buffer, no message will be sent now. Code 1150 * elsewhere will send the EOF when the buffer 1151 * becomes empty if stdin_eof is set. 1152 */ 1153 if (buffer_len(&stdin_buffer) == 0) { 1154 packet_start(SSH_CMSG_EOF); 1155 packet_send(); 1156 } 1157 } else if (escape_char1 == SSH_ESCAPECHAR_NONE) { 1158 /* 1159 * Normal successful read, and no escape character. 1160 * Just append the data to buffer. 1161 */ 1162 buffer_append(&stdin_buffer, buf, len); 1163 } else { 1164 /* 1165 * Normal, successful read. But we have an escape 1166 * character and have to process the characters one 1167 * by one. 1168 */ 1169 if (process_escapes(NULL, &stdin_buffer, 1170 &stdout_buffer, &stderr_buffer, buf, len) == -1) 1171 return; 1172 } 1173 } 1174 } 1175 1176 static void 1177 client_process_output(fd_set *writeset) 1178 { 1179 int len; 1180 char buf[100]; 1181 1182 /* Write buffered output to stdout. */ 1183 if (FD_ISSET(fileno(stdout), writeset)) { 1184 /* Write as much data as possible. */ 1185 len = write(fileno(stdout), buffer_ptr(&stdout_buffer), 1186 buffer_len(&stdout_buffer)); 1187 if (len <= 0) { 1188 if (errno == EINTR || errno == EAGAIN) 1189 len = 0; 1190 else { 1191 /* 1192 * An error or EOF was encountered. Put an 1193 * error message to stderr buffer. 1194 */ 1195 snprintf(buf, sizeof buf, 1196 "write stdout: %.50s\r\n", strerror(errno)); 1197 buffer_append(&stderr_buffer, buf, strlen(buf)); 1198 quit_pending = 1; 1199 return; 1200 } 1201 } 1202 /* Consume printed data from the buffer. */ 1203 buffer_consume(&stdout_buffer, len); 1204 } 1205 /* Write buffered output to stderr. */ 1206 if (FD_ISSET(fileno(stderr), writeset)) { 1207 /* Write as much data as possible. */ 1208 len = write(fileno(stderr), buffer_ptr(&stderr_buffer), 1209 buffer_len(&stderr_buffer)); 1210 if (len <= 0) { 1211 if (errno == EINTR || errno == EAGAIN) 1212 len = 0; 1213 else { 1214 /* 1215 * EOF or error, but can't even print 1216 * error message. 1217 */ 1218 quit_pending = 1; 1219 return; 1220 } 1221 } 1222 /* Consume printed characters from the buffer. */ 1223 buffer_consume(&stderr_buffer, len); 1224 } 1225 } 1226 1227 /* 1228 * Get packets from the connection input buffer, and process them as long as 1229 * there are packets available. 1230 * 1231 * Any unknown packets received during the actual 1232 * session cause the session to terminate. This is 1233 * intended to make debugging easier since no 1234 * confirmations are sent. Any compatible protocol 1235 * extensions must be negotiated during the 1236 * preparatory phase. 1237 */ 1238 1239 static void 1240 client_process_buffered_input_packets(void) 1241 { 1242 dispatch_run(DISPATCH_NONBLOCK, &quit_pending, 1243 compat20 ? xxx_kex : NULL); 1244 } 1245 1246 /* scan buf[] for '~' before sending data to the peer */ 1247 1248 /* Helper: allocate a new escape_filter_ctx and fill in its escape char */ 1249 void * 1250 client_new_escape_filter_ctx(int escape_char) 1251 { 1252 struct escape_filter_ctx *ret; 1253 1254 ret = xmalloc(sizeof(*ret)); 1255 ret->escape_pending = 0; 1256 ret->escape_char = escape_char; 1257 return (void *)ret; 1258 } 1259 1260 /* Free the escape filter context on channel free */ 1261 void 1262 client_filter_cleanup(int cid, void *ctx) 1263 { 1264 xfree(ctx); 1265 } 1266 1267 int 1268 client_simple_escape_filter(Channel *c, char *buf, int len) 1269 { 1270 if (c->extended_usage != CHAN_EXTENDED_WRITE) 1271 return 0; 1272 1273 return process_escapes(c, &c->input, &c->output, &c->extended, 1274 buf, len); 1275 } 1276 1277 static void 1278 client_channel_closed(int id, void *arg) 1279 { 1280 channel_cancel_cleanup(id); 1281 session_closed = 1; 1282 leave_raw_mode(); 1283 } 1284 1285 /* 1286 * Implements the interactive session with the server. This is called after 1287 * the user has been authenticated, and a command has been started on the 1288 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character 1289 * used as an escape character for terminating or suspending the session. 1290 */ 1291 1292 int 1293 client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id) 1294 { 1295 fd_set *readset = NULL, *writeset = NULL; 1296 double start_time, total_time; 1297 int max_fd = 0, max_fd2 = 0, len, rekeying = 0; 1298 u_int64_t ibytes, obytes; 1299 u_int nalloc = 0; 1300 char buf[100]; 1301 1302 debug("Entering interactive session."); 1303 1304 start_time = get_current_time(); 1305 1306 /* Initialize variables. */ 1307 escape_pending1 = 0; 1308 last_was_cr = 1; 1309 exit_status = -1; 1310 stdin_eof = 0; 1311 buffer_high = 64 * 1024; 1312 connection_in = packet_get_connection_in(); 1313 connection_out = packet_get_connection_out(); 1314 max_fd = MAX(connection_in, connection_out); 1315 if (muxserver_sock != -1) 1316 max_fd = MAX(max_fd, muxserver_sock); 1317 1318 if (!compat20) { 1319 /* enable nonblocking unless tty */ 1320 if (!isatty(fileno(stdin))) 1321 set_nonblock(fileno(stdin)); 1322 if (!isatty(fileno(stdout))) 1323 set_nonblock(fileno(stdout)); 1324 if (!isatty(fileno(stderr))) 1325 set_nonblock(fileno(stderr)); 1326 max_fd = MAX(max_fd, fileno(stdin)); 1327 max_fd = MAX(max_fd, fileno(stdout)); 1328 max_fd = MAX(max_fd, fileno(stderr)); 1329 } 1330 quit_pending = 0; 1331 escape_char1 = escape_char_arg; 1332 1333 /* Initialize buffers. */ 1334 buffer_init(&stdin_buffer); 1335 buffer_init(&stdout_buffer); 1336 buffer_init(&stderr_buffer); 1337 1338 client_init_dispatch(); 1339 1340 /* 1341 * Set signal handlers, (e.g. to restore non-blocking mode) 1342 * but don't overwrite SIG_IGN, matches behaviour from rsh(1) 1343 */ 1344 if (signal(SIGHUP, SIG_IGN) != SIG_IGN) 1345 signal(SIGHUP, signal_handler); 1346 if (signal(SIGINT, SIG_IGN) != SIG_IGN) 1347 signal(SIGINT, signal_handler); 1348 if (signal(SIGQUIT, SIG_IGN) != SIG_IGN) 1349 signal(SIGQUIT, signal_handler); 1350 if (signal(SIGTERM, SIG_IGN) != SIG_IGN) 1351 signal(SIGTERM, signal_handler); 1352 signal(SIGWINCH, window_change_handler); 1353 1354 if (have_pty) 1355 enter_raw_mode(); 1356 1357 if (compat20) { 1358 session_ident = ssh2_chan_id; 1359 if (escape_char_arg != SSH_ESCAPECHAR_NONE) 1360 channel_register_filter(session_ident, 1361 client_simple_escape_filter, NULL, 1362 client_filter_cleanup, 1363 client_new_escape_filter_ctx(escape_char_arg)); 1364 if (session_ident != -1) 1365 channel_register_cleanup(session_ident, 1366 client_channel_closed, 0); 1367 } else { 1368 /* Check if we should immediately send eof on stdin. */ 1369 client_check_initial_eof_on_stdin(); 1370 } 1371 1372 /* Main loop of the client for the interactive session mode. */ 1373 while (!quit_pending) { 1374 1375 /* Process buffered packets sent by the server. */ 1376 client_process_buffered_input_packets(); 1377 1378 if (compat20 && session_closed && !channel_still_open()) 1379 break; 1380 1381 rekeying = (xxx_kex != NULL && !xxx_kex->done); 1382 1383 if (rekeying) { 1384 debug("rekeying in progress"); 1385 } else { 1386 /* 1387 * Make packets of buffered stdin data, and buffer 1388 * them for sending to the server. 1389 */ 1390 if (!compat20) 1391 client_make_packets_from_stdin_data(); 1392 1393 /* 1394 * Make packets from buffered channel data, and 1395 * enqueue them for sending to the server. 1396 */ 1397 if (packet_not_very_much_data_to_write()) 1398 channel_output_poll(); 1399 1400 /* 1401 * Check if the window size has changed, and buffer a 1402 * message about it to the server if so. 1403 */ 1404 client_check_window_change(); 1405 1406 if (quit_pending) 1407 break; 1408 } 1409 /* 1410 * Wait until we have something to do (something becomes 1411 * available on one of the descriptors). 1412 */ 1413 max_fd2 = max_fd; 1414 client_wait_until_can_do_something(&readset, &writeset, 1415 &max_fd2, &nalloc, rekeying); 1416 1417 if (quit_pending) 1418 break; 1419 1420 /* Do channel operations unless rekeying in progress. */ 1421 if (!rekeying) { 1422 channel_after_select(readset, writeset); 1423 if (need_rekeying || packet_need_rekeying()) { 1424 debug("need rekeying"); 1425 xxx_kex->done = 0; 1426 kex_send_kexinit(xxx_kex); 1427 need_rekeying = 0; 1428 } 1429 } 1430 1431 /* Buffer input from the connection. */ 1432 client_process_net_input(readset); 1433 1434 /* Accept control connections. */ 1435 if (muxserver_sock != -1 &&FD_ISSET(muxserver_sock, readset)) { 1436 if (muxserver_accept_control()) 1437 quit_pending = 1; 1438 } 1439 1440 if (quit_pending) 1441 break; 1442 1443 if (!compat20) { 1444 /* Buffer data from stdin */ 1445 client_process_input(readset); 1446 /* 1447 * Process output to stdout and stderr. Output to 1448 * the connection is processed elsewhere (above). 1449 */ 1450 client_process_output(writeset); 1451 } 1452 1453 if (session_resumed) { 1454 connection_in = packet_get_connection_in(); 1455 connection_out = packet_get_connection_out(); 1456 max_fd = MAX(max_fd, connection_out); 1457 max_fd = MAX(max_fd, connection_in); 1458 session_resumed = 0; 1459 } 1460 1461 /* 1462 * Send as much buffered packet data as possible to the 1463 * sender. 1464 */ 1465 if (FD_ISSET(connection_out, writeset)) 1466 packet_write_poll(); 1467 } 1468 if (readset) 1469 xfree(readset); 1470 if (writeset) 1471 xfree(writeset); 1472 1473 /* Terminate the session. */ 1474 1475 /* Stop watching for window change. */ 1476 signal(SIGWINCH, SIG_DFL); 1477 1478 if (compat20) { 1479 packet_start(SSH2_MSG_DISCONNECT); 1480 packet_put_int(SSH2_DISCONNECT_BY_APPLICATION); 1481 packet_put_cstring("disconnected by user"); 1482 packet_send(); 1483 packet_write_wait(); 1484 } 1485 1486 channel_free_all(); 1487 1488 if (have_pty) 1489 leave_raw_mode(); 1490 1491 /* restore blocking io */ 1492 if (!isatty(fileno(stdin))) 1493 unset_nonblock(fileno(stdin)); 1494 if (!isatty(fileno(stdout))) 1495 unset_nonblock(fileno(stdout)); 1496 if (!isatty(fileno(stderr))) 1497 unset_nonblock(fileno(stderr)); 1498 1499 /* 1500 * If there was no shell or command requested, there will be no remote 1501 * exit status to be returned. In that case, clear error code if the 1502 * connection was deliberately terminated at this end. 1503 */ 1504 if (no_shell_flag && received_signal == SIGTERM) { 1505 received_signal = 0; 1506 exit_status = 0; 1507 } 1508 1509 if (received_signal) 1510 fatal("Killed by signal %d.", (int) received_signal); 1511 1512 /* 1513 * In interactive mode (with pseudo tty) display a message indicating 1514 * that the connection has been closed. 1515 */ 1516 if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) { 1517 snprintf(buf, sizeof buf, 1518 "Connection to %.64s closed.\r\n", host); 1519 buffer_append(&stderr_buffer, buf, strlen(buf)); 1520 } 1521 1522 /* Output any buffered data for stdout. */ 1523 while (buffer_len(&stdout_buffer) > 0) { 1524 len = write(fileno(stdout), buffer_ptr(&stdout_buffer), 1525 buffer_len(&stdout_buffer)); 1526 if (len <= 0) { 1527 error("Write failed flushing stdout buffer."); 1528 break; 1529 } 1530 buffer_consume(&stdout_buffer, len); 1531 } 1532 1533 /* Output any buffered data for stderr. */ 1534 while (buffer_len(&stderr_buffer) > 0) { 1535 len = write(fileno(stderr), buffer_ptr(&stderr_buffer), 1536 buffer_len(&stderr_buffer)); 1537 if (len <= 0) { 1538 error("Write failed flushing stderr buffer."); 1539 break; 1540 } 1541 buffer_consume(&stderr_buffer, len); 1542 } 1543 1544 /* Clear and free any buffers. */ 1545 memset(buf, 0, sizeof(buf)); 1546 buffer_free(&stdin_buffer); 1547 buffer_free(&stdout_buffer); 1548 buffer_free(&stderr_buffer); 1549 1550 /* Report bytes transferred, and transfer rates. */ 1551 total_time = get_current_time() - start_time; 1552 packet_get_state(MODE_IN, NULL, NULL, NULL, &ibytes); 1553 packet_get_state(MODE_OUT, NULL, NULL, NULL, &obytes); 1554 verbose("Transferred: sent %llu, received %llu bytes, in %.1f seconds", 1555 obytes, ibytes, total_time); 1556 if (total_time > 0) 1557 verbose("Bytes per second: sent %.1f, received %.1f", 1558 obytes / total_time, ibytes / total_time); 1559 /* Return the exit status of the program. */ 1560 debug("Exit status %d", exit_status); 1561 return exit_status; 1562 } 1563 1564 /*********/ 1565 1566 static void 1567 client_input_stdout_data(int type, u_int32_t seq, void *ctxt) 1568 { 1569 u_int data_len; 1570 char *data = packet_get_string(&data_len); 1571 packet_check_eom(); 1572 buffer_append(&stdout_buffer, data, data_len); 1573 memset(data, 0, data_len); 1574 xfree(data); 1575 } 1576 static void 1577 client_input_stderr_data(int type, u_int32_t seq, void *ctxt) 1578 { 1579 u_int data_len; 1580 char *data = packet_get_string(&data_len); 1581 packet_check_eom(); 1582 buffer_append(&stderr_buffer, data, data_len); 1583 memset(data, 0, data_len); 1584 xfree(data); 1585 } 1586 static void 1587 client_input_exit_status(int type, u_int32_t seq, void *ctxt) 1588 { 1589 exit_status = packet_get_int(); 1590 packet_check_eom(); 1591 /* Acknowledge the exit. */ 1592 packet_start(SSH_CMSG_EXIT_CONFIRMATION); 1593 packet_send(); 1594 /* 1595 * Must wait for packet to be sent since we are 1596 * exiting the loop. 1597 */ 1598 packet_write_wait(); 1599 /* Flag that we want to exit. */ 1600 quit_pending = 1; 1601 } 1602 static void 1603 client_input_agent_open(int type, u_int32_t seq, void *ctxt) 1604 { 1605 Channel *c = NULL; 1606 int remote_id, sock; 1607 1608 /* Read the remote channel number from the message. */ 1609 remote_id = packet_get_int(); 1610 packet_check_eom(); 1611 1612 /* 1613 * Get a connection to the local authentication agent (this may again 1614 * get forwarded). 1615 */ 1616 sock = ssh_get_authentication_socket(); 1617 1618 /* 1619 * If we could not connect the agent, send an error message back to 1620 * the server. This should never happen unless the agent dies, 1621 * because authentication forwarding is only enabled if we have an 1622 * agent. 1623 */ 1624 if (sock >= 0) { 1625 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock, 1626 -1, 0, 0, 0, "authentication agent connection", 1); 1627 c->remote_id = remote_id; 1628 c->force_drain = 1; 1629 } 1630 if (c == NULL) { 1631 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 1632 packet_put_int(remote_id); 1633 } else { 1634 /* Send a confirmation to the remote host. */ 1635 debug("Forwarding authentication connection."); 1636 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); 1637 packet_put_int(remote_id); 1638 packet_put_int(c->self); 1639 } 1640 packet_send(); 1641 } 1642 1643 static Channel * 1644 client_request_forwarded_tcpip(const char *request_type, int rchan) 1645 { 1646 Channel *c = NULL; 1647 char *listen_address, *originator_address; 1648 u_short listen_port, originator_port; 1649 1650 /* Get rest of the packet */ 1651 listen_address = packet_get_string(NULL); 1652 listen_port = packet_get_int(); 1653 originator_address = packet_get_string(NULL); 1654 originator_port = packet_get_int(); 1655 packet_check_eom(); 1656 1657 debug("client_request_forwarded_tcpip: listen %s port %d, " 1658 "originator %s port %d", listen_address, listen_port, 1659 originator_address, originator_port); 1660 1661 c = channel_connect_by_listen_address(listen_port, 1662 "forwarded-tcpip", originator_address); 1663 1664 xfree(originator_address); 1665 xfree(listen_address); 1666 return c; 1667 } 1668 1669 static Channel * 1670 client_request_x11(const char *request_type, int rchan) 1671 { 1672 Channel *c = NULL; 1673 char *originator; 1674 u_short originator_port; 1675 int sock; 1676 1677 if (!options.forward_x11) { 1678 error("Warning: ssh server tried X11 forwarding."); 1679 error("Warning: this is probably a break-in attempt by a " 1680 "malicious server."); 1681 return NULL; 1682 } 1683 originator = packet_get_string(NULL); 1684 if (datafellows & SSH_BUG_X11FWD) { 1685 debug2("buggy server: x11 request w/o originator_port"); 1686 originator_port = 0; 1687 } else { 1688 originator_port = packet_get_int(); 1689 } 1690 packet_check_eom(); 1691 /* XXX check permission */ 1692 debug("client_request_x11: request from %s %d", originator, 1693 originator_port); 1694 xfree(originator); 1695 sock = x11_connect_display(); 1696 if (sock < 0) 1697 return NULL; 1698 c = channel_new("x11", 1699 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1700 CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); 1701 c->force_drain = 1; 1702 return c; 1703 } 1704 1705 static Channel * 1706 client_request_agent(const char *request_type, int rchan) 1707 { 1708 Channel *c = NULL; 1709 int sock; 1710 1711 if (!options.forward_agent) { 1712 error("Warning: ssh server tried agent forwarding."); 1713 error("Warning: this is probably a break-in attempt by a " 1714 "malicious server."); 1715 return NULL; 1716 } 1717 sock = ssh_get_authentication_socket(); 1718 if (sock < 0) 1719 return NULL; 1720 c = channel_new("authentication agent connection", 1721 SSH_CHANNEL_OPEN, sock, sock, -1, 1722 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, 1723 "authentication agent connection", 1); 1724 c->force_drain = 1; 1725 return c; 1726 } 1727 1728 int 1729 client_request_tun_fwd(int tun_mode, int local_tun, int remote_tun) 1730 { 1731 Channel *c; 1732 int fd; 1733 1734 if (tun_mode == SSH_TUNMODE_NO) 1735 return 0; 1736 1737 if (!compat20) { 1738 error("Tunnel forwarding is not supported for protocol 1"); 1739 return -1; 1740 } 1741 1742 debug("Requesting tun unit %d in mode %d", local_tun, tun_mode); 1743 1744 /* Open local tunnel device */ 1745 if ((fd = tun_open(local_tun, tun_mode)) == -1) { 1746 error("Tunnel device open failed."); 1747 return -1; 1748 } 1749 1750 c = channel_new("tun", SSH_CHANNEL_OPENING, fd, fd, -1, 1751 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1); 1752 c->datagram = 1; 1753 1754 packet_start(SSH2_MSG_CHANNEL_OPEN); 1755 packet_put_cstring("tun@openssh.com"); 1756 packet_put_int(c->self); 1757 packet_put_int(c->local_window_max); 1758 packet_put_int(c->local_maxpacket); 1759 packet_put_int(tun_mode); 1760 packet_put_int(remote_tun); 1761 packet_send(); 1762 1763 return 0; 1764 } 1765 1766 /* XXXX move to generic input handler */ 1767 static void 1768 client_input_channel_open(int type, u_int32_t seq, void *ctxt) 1769 { 1770 Channel *c = NULL; 1771 char *ctype; 1772 int rchan; 1773 u_int rmaxpack, rwindow, len; 1774 1775 ctype = packet_get_string(&len); 1776 rchan = packet_get_int(); 1777 rwindow = packet_get_int(); 1778 rmaxpack = packet_get_int(); 1779 1780 debug("client_input_channel_open: ctype %s rchan %d win %d max %d", 1781 ctype, rchan, rwindow, rmaxpack); 1782 1783 if (strcmp(ctype, "forwarded-tcpip") == 0) { 1784 c = client_request_forwarded_tcpip(ctype, rchan); 1785 } else if (strcmp(ctype, "x11") == 0) { 1786 c = client_request_x11(ctype, rchan); 1787 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) { 1788 c = client_request_agent(ctype, rchan); 1789 } 1790 /* XXX duplicate : */ 1791 if (c != NULL) { 1792 debug("confirm %s", ctype); 1793 c->remote_id = rchan; 1794 c->remote_window = rwindow; 1795 c->remote_maxpacket = rmaxpack; 1796 if (c->type != SSH_CHANNEL_CONNECTING) { 1797 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); 1798 packet_put_int(c->remote_id); 1799 packet_put_int(c->self); 1800 packet_put_int(c->local_window); 1801 packet_put_int(c->local_maxpacket); 1802 packet_send(); 1803 } 1804 } else { 1805 debug("failure %s", ctype); 1806 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); 1807 packet_put_int(rchan); 1808 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED); 1809 if (!(datafellows & SSH_BUG_OPENFAILURE)) { 1810 packet_put_cstring("open failed"); 1811 packet_put_cstring(""); 1812 } 1813 packet_send(); 1814 } 1815 xfree(ctype); 1816 } 1817 static void 1818 client_input_channel_req(int type, u_int32_t seq, void *ctxt) 1819 { 1820 Channel *c = NULL; 1821 int exitval, id, reply, success = 0; 1822 char *rtype; 1823 1824 id = packet_get_int(); 1825 rtype = packet_get_string(NULL); 1826 reply = packet_get_char(); 1827 1828 debug("client_input_channel_req: channel %d rtype %s reply %d", 1829 id, rtype, reply); 1830 1831 if (id == -1) { 1832 error("client_input_channel_req: request for channel -1"); 1833 } else if ((c = channel_lookup(id)) == NULL) { 1834 error("client_input_channel_req: channel %d: " 1835 "unknown channel", id); 1836 } else if (strcmp(rtype, "eow@openssh.com") == 0) { 1837 packet_check_eom(); 1838 chan_rcvd_eow(c); 1839 } else if (strcmp(rtype, "exit-status") == 0) { 1840 exitval = packet_get_int(); 1841 if (c->ctl_fd != -1) { 1842 /* Dispatch to mux client */ 1843 atomicio(vwrite, c->ctl_fd, &exitval, sizeof(exitval)); 1844 success = 1; 1845 } else if (id == session_ident) { 1846 /* Record exit value of local session */ 1847 success = 1; 1848 exit_status = exitval; 1849 } else { 1850 error("client_input_channel_req: unexpected channel %d", 1851 session_ident); 1852 } 1853 packet_check_eom(); 1854 } 1855 if (reply) { 1856 packet_start(success ? 1857 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE); 1858 packet_put_int(c->remote_id); 1859 packet_send(); 1860 } 1861 xfree(rtype); 1862 } 1863 static void 1864 client_input_global_request(int type, u_int32_t seq, void *ctxt) 1865 { 1866 char *rtype; 1867 int want_reply; 1868 int success = 0; 1869 1870 rtype = packet_get_string(NULL); 1871 want_reply = packet_get_char(); 1872 debug("client_input_global_request: rtype %s want_reply %d", 1873 rtype, want_reply); 1874 if (want_reply) { 1875 packet_start(success ? 1876 SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE); 1877 packet_send(); 1878 packet_write_wait(); 1879 } 1880 xfree(rtype); 1881 } 1882 1883 void 1884 client_session2_setup(int id, int want_tty, int want_subsystem, 1885 const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env) 1886 { 1887 int len; 1888 Channel *c = NULL; 1889 1890 debug2("%s: id %d", __func__, id); 1891 1892 if ((c = channel_lookup(id)) == NULL) 1893 fatal("client_session2_setup: channel %d: unknown channel", id); 1894 1895 if (want_tty) { 1896 struct winsize ws; 1897 1898 /* Store window size in the packet. */ 1899 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0) 1900 memset(&ws, 0, sizeof(ws)); 1901 1902 channel_request_start(id, "pty-req", 1); 1903 client_expect_confirm(id, "PTY allocation", 0); 1904 packet_put_cstring(term != NULL ? term : ""); 1905 packet_put_int((u_int)ws.ws_col); 1906 packet_put_int((u_int)ws.ws_row); 1907 packet_put_int((u_int)ws.ws_xpixel); 1908 packet_put_int((u_int)ws.ws_ypixel); 1909 if (tiop == NULL) 1910 tiop = get_saved_tio(); 1911 tty_make_modes(-1, tiop); 1912 packet_send(); 1913 /* XXX wait for reply */ 1914 c->client_tty = 1; 1915 } 1916 1917 /* Transfer any environment variables from client to server */ 1918 if (options.num_send_env != 0 && env != NULL) { 1919 int i, j, matched; 1920 char *name, *val; 1921 1922 debug("Sending environment."); 1923 for (i = 0; env[i] != NULL; i++) { 1924 /* Split */ 1925 name = xstrdup(env[i]); 1926 if ((val = strchr(name, '=')) == NULL) { 1927 xfree(name); 1928 continue; 1929 } 1930 *val++ = '\0'; 1931 1932 matched = 0; 1933 for (j = 0; j < options.num_send_env; j++) { 1934 if (match_pattern(name, options.send_env[j])) { 1935 matched = 1; 1936 break; 1937 } 1938 } 1939 if (!matched) { 1940 debug3("Ignored env %s", name); 1941 xfree(name); 1942 continue; 1943 } 1944 1945 debug("Sending env %s = %s", name, val); 1946 channel_request_start(id, "env", 0); 1947 packet_put_cstring(name); 1948 packet_put_cstring(val); 1949 packet_send(); 1950 xfree(name); 1951 } 1952 } 1953 1954 len = buffer_len(cmd); 1955 if (len > 0) { 1956 if (len > 900) 1957 len = 900; 1958 if (want_subsystem) { 1959 debug("Sending subsystem: %.*s", 1960 len, (u_char*)buffer_ptr(cmd)); 1961 channel_request_start(id, "subsystem", 1); 1962 client_expect_confirm(id, "subsystem", 1); 1963 } else { 1964 debug("Sending command: %.*s", 1965 len, (u_char*)buffer_ptr(cmd)); 1966 channel_request_start(id, "exec", 1); 1967 client_expect_confirm(id, "exec", 1); 1968 } 1969 packet_put_string(buffer_ptr(cmd), buffer_len(cmd)); 1970 packet_send(); 1971 } else { 1972 channel_request_start(id, "shell", 1); 1973 client_expect_confirm(id, "shell", 1); 1974 packet_send(); 1975 } 1976 } 1977 1978 static void 1979 client_init_dispatch_20(void) 1980 { 1981 dispatch_init(&dispatch_protocol_error); 1982 1983 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); 1984 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); 1985 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); 1986 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); 1987 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open); 1988 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 1989 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 1990 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req); 1991 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); 1992 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm); 1993 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm); 1994 dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request); 1995 1996 /* rekeying */ 1997 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); 1998 1999 /* global request reply messages */ 2000 dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply); 2001 dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply); 2002 } 2003 2004 static void 2005 client_init_dispatch_13(void) 2006 { 2007 dispatch_init(NULL); 2008 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close); 2009 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation); 2010 dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data); 2011 dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 2012 dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 2013 dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open); 2014 dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status); 2015 dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data); 2016 dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data); 2017 2018 dispatch_set(SSH_SMSG_AGENT_OPEN, options.forward_agent ? 2019 &client_input_agent_open : &deny_input_open); 2020 dispatch_set(SSH_SMSG_X11_OPEN, options.forward_x11 ? 2021 &x11_input_open : &deny_input_open); 2022 } 2023 2024 static void 2025 client_init_dispatch_15(void) 2026 { 2027 client_init_dispatch_13(); 2028 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof); 2029 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose); 2030 } 2031 2032 static void 2033 client_init_dispatch(void) 2034 { 2035 if (compat20) 2036 client_init_dispatch_20(); 2037 else if (compat13) 2038 client_init_dispatch_13(); 2039 else 2040 client_init_dispatch_15(); 2041 } 2042 2043 /* client specific fatal cleanup */ 2044 void 2045 cleanup_exit(int i) 2046 { 2047 leave_raw_mode(); 2048 leave_non_blocking(); 2049 if (options.control_path != NULL && muxserver_sock != -1) 2050 unlink(options.control_path); 2051 _exit(i); 2052 } 2053