1 /* $NetBSD: clientloop.c,v 1.2 2009/06/07 22:38:46 christos Exp $ */ 2 /* $OpenBSD: clientloop.c,v 1.209 2009/02/12 03:00:56 djm Exp $ */ 3 /* 4 * Author: Tatu Ylonen <ylo@cs.hut.fi> 5 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 6 * All rights reserved 7 * The main loop for the interactive session (client side). 8 * 9 * As far as I am concerned, the code I have written for this software 10 * can be used freely for any purpose. Any derived versions of this 11 * software must be clearly marked as such, and if the derived work is 12 * incompatible with the protocol description in the RFC file, it must be 13 * called by a name other than "ssh" or "Secure Shell". 14 * 15 * 16 * Copyright (c) 1999 Theo de Raadt. All rights reserved. 17 * 18 * Redistribution and use in source and binary forms, with or without 19 * modification, are permitted provided that the following conditions 20 * are met: 21 * 1. Redistributions of source code must retain the above copyright 22 * notice, this list of conditions and the following disclaimer. 23 * 2. Redistributions in binary form must reproduce the above copyright 24 * notice, this list of conditions and the following disclaimer in the 25 * documentation and/or other materials provided with the distribution. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 28 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 29 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 30 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 31 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 32 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 33 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 34 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 35 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 36 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 37 * 38 * 39 * SSH2 support added by Markus Friedl. 40 * Copyright (c) 1999, 2000, 2001 Markus Friedl. All rights reserved. 41 * 42 * Redistribution and use in source and binary forms, with or without 43 * modification, are permitted provided that the following conditions 44 * are met: 45 * 1. Redistributions of source code must retain the above copyright 46 * notice, this list of conditions and the following disclaimer. 47 * 2. Redistributions in binary form must reproduce the above copyright 48 * notice, this list of conditions and the following disclaimer in the 49 * documentation and/or other materials provided with the distribution. 50 * 51 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 52 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 53 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 54 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 55 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 56 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 57 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 58 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 59 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 60 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 61 */ 62 63 #include "includes.h" 64 __RCSID("$NetBSD: clientloop.c,v 1.2 2009/06/07 22:38:46 christos Exp $"); 65 #include <sys/types.h> 66 #include <sys/ioctl.h> 67 #include <sys/stat.h> 68 #include <sys/socket.h> 69 #include <sys/time.h> 70 #include <sys/param.h> 71 #include <sys/queue.h> 72 73 #include <ctype.h> 74 #include <errno.h> 75 #include <paths.h> 76 #include <signal.h> 77 #include <stdio.h> 78 #include <stdlib.h> 79 #include <string.h> 80 #include <termios.h> 81 #include <pwd.h> 82 #include <unistd.h> 83 84 #include "xmalloc.h" 85 #include "ssh.h" 86 #include "ssh1.h" 87 #include "ssh2.h" 88 #include "packet.h" 89 #include "buffer.h" 90 #include "compat.h" 91 #include "channels.h" 92 #include "dispatch.h" 93 #include "key.h" 94 #include "cipher.h" 95 #include "kex.h" 96 #include "log.h" 97 #include "readconf.h" 98 #include "clientloop.h" 99 #include "sshconnect.h" 100 #include "authfd.h" 101 #include "atomicio.h" 102 #include "sshpty.h" 103 #include "misc.h" 104 #include "match.h" 105 #include "msg.h" 106 #include "getpeereid.h" 107 108 /* import options */ 109 extern Options options; 110 111 /* Flag indicating that stdin should be redirected from /dev/null. */ 112 extern int stdin_null_flag; 113 114 /* Flag indicating that no shell has been requested */ 115 extern int no_shell_flag; 116 117 /* Control socket */ 118 extern int muxserver_sock; 119 120 /* 121 * Name of the host we are connecting to. This is the name given on the 122 * command line, or the HostName specified for the user-supplied name in a 123 * configuration file. 124 */ 125 extern char *host; 126 127 /* 128 * Flag to indicate that we have received a window change signal which has 129 * not yet been processed. This will cause a message indicating the new 130 * window size to be sent to the server a little later. This is volatile 131 * because this is updated in a signal handler. 132 */ 133 static volatile sig_atomic_t received_window_change_signal = 0; 134 static volatile sig_atomic_t received_signal = 0; 135 136 /* Flag indicating whether the user's terminal is in non-blocking mode. */ 137 static int in_non_blocking_mode = 0; 138 139 /* Common data for the client loop code. */ 140 static volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */ 141 static int escape_char1; /* Escape character. (proto1 only) */ 142 static int escape_pending1; /* Last character was an escape (proto1 only) */ 143 static int last_was_cr; /* Last character was a newline. */ 144 static int exit_status; /* Used to store the command exit status. */ 145 static int stdin_eof; /* EOF has been encountered on stderr. */ 146 static Buffer stdin_buffer; /* Buffer for stdin data. */ 147 static Buffer stdout_buffer; /* Buffer for stdout data. */ 148 static Buffer stderr_buffer; /* Buffer for stderr data. */ 149 static u_int buffer_high;/* Soft max buffer size. */ 150 static int connection_in; /* Connection to server (input). */ 151 static int connection_out; /* Connection to server (output). */ 152 static int need_rekeying; /* Set to non-zero if rekeying is requested. */ 153 static int session_closed = 0; /* In SSH2: login session closed. */ 154 155 static void client_init_dispatch(void); 156 int session_ident = -1; 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 keep_alive_timeouts = 0; 490 } 491 492 static void 493 server_alive_check(void) 494 { 495 if (++keep_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; 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 = read(connection_in, buf, sizeof(buf)); 642 if (len == 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((unsigned char)*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 s++; 828 while (isspace((unsigned char)*s)) 829 s++; 830 831 if (delete) { 832 cancel_port = 0; 833 cancel_host = hpdelim(&s); /* may be NULL */ 834 if (s != NULL) { 835 cancel_port = a2port(s); 836 cancel_host = cleanhostname(cancel_host); 837 } else { 838 cancel_port = a2port(cancel_host); 839 cancel_host = NULL; 840 } 841 if (cancel_port <= 0) { 842 logit("Bad forwarding close port"); 843 goto out; 844 } 845 channel_request_rforward_cancel(cancel_host, cancel_port); 846 } else { 847 if (!parse_forward(&fwd, s, dynamic, remote)) { 848 logit("Bad forwarding specification."); 849 goto out; 850 } 851 if (local || dynamic) { 852 if (channel_setup_local_fwd_listener(fwd.listen_host, 853 fwd.listen_port, fwd.connect_host, 854 fwd.connect_port, options.gateway_ports) < 0) { 855 logit("Port forwarding failed."); 856 goto out; 857 } 858 } else { 859 if (channel_request_remote_forwarding(fwd.listen_host, 860 fwd.listen_port, fwd.connect_host, 861 fwd.connect_port) < 0) { 862 logit("Port forwarding failed."); 863 goto out; 864 } 865 } 866 867 logit("Forwarding port."); 868 } 869 870 out: 871 signal(SIGINT, handler); 872 enter_raw_mode(); 873 if (cmd) 874 xfree(cmd); 875 if (fwd.listen_host != NULL) 876 xfree(fwd.listen_host); 877 if (fwd.connect_host != NULL) 878 xfree(fwd.connect_host); 879 } 880 881 /* 882 * Process the characters one by one, call with c==NULL for proto1 case. 883 */ 884 static int 885 process_escapes(Channel *c, Buffer *bin, Buffer *bout, Buffer *berr, 886 char *buf, int len) 887 { 888 char string[1024]; 889 pid_t pid; 890 int bytes = 0; 891 u_int i; 892 u_char ch; 893 char *s; 894 int *escape_pendingp, escape_char; 895 struct escape_filter_ctx *efc; 896 897 if (c == NULL) { 898 escape_pendingp = &escape_pending1; 899 escape_char = escape_char1; 900 } else { 901 if (c->filter_ctx == NULL) 902 return 0; 903 efc = (struct escape_filter_ctx *)c->filter_ctx; 904 escape_pendingp = &efc->escape_pending; 905 escape_char = efc->escape_char; 906 } 907 908 if (len <= 0) 909 return (0); 910 911 for (i = 0; i < (u_int)len; i++) { 912 /* Get one character at a time. */ 913 ch = buf[i]; 914 915 if (*escape_pendingp) { 916 /* We have previously seen an escape character. */ 917 /* Clear the flag now. */ 918 *escape_pendingp = 0; 919 920 /* Process the escaped character. */ 921 switch (ch) { 922 case '.': 923 /* Terminate the connection. */ 924 snprintf(string, sizeof string, "%c.\r\n", 925 escape_char); 926 buffer_append(berr, string, strlen(string)); 927 928 if (c && c->ctl_fd != -1) { 929 chan_read_failed(c); 930 chan_write_failed(c); 931 return 0; 932 } else 933 quit_pending = 1; 934 return -1; 935 936 case 'Z' - 64: 937 /* XXX support this for mux clients */ 938 if (c && c->ctl_fd != -1) { 939 noescape: 940 snprintf(string, sizeof string, 941 "%c%c escape not available to " 942 "multiplexed sessions\r\n", 943 escape_char, ch); 944 buffer_append(berr, string, 945 strlen(string)); 946 continue; 947 } 948 /* Suspend the program. Inform the user */ 949 snprintf(string, sizeof string, 950 "%c^Z [suspend ssh]\r\n", escape_char); 951 buffer_append(berr, string, strlen(string)); 952 953 /* Restore terminal modes and suspend. */ 954 client_suspend_self(bin, bout, berr); 955 956 /* We have been continued. */ 957 continue; 958 959 case 'B': 960 if (compat20) { 961 snprintf(string, sizeof string, 962 "%cB\r\n", escape_char); 963 buffer_append(berr, string, 964 strlen(string)); 965 channel_request_start(session_ident, 966 "break", 0); 967 packet_put_int(1000); 968 packet_send(); 969 } 970 continue; 971 972 case 'R': 973 if (compat20) { 974 if (datafellows & SSH_BUG_NOREKEY) 975 logit("Server does not " 976 "support re-keying"); 977 else 978 need_rekeying = 1; 979 } 980 continue; 981 982 case '&': 983 if (c && c->ctl_fd != -1) 984 goto noescape; 985 /* 986 * Detach the program (continue to serve 987 * connections, but put in background and no 988 * more new connections). 989 */ 990 /* Restore tty modes. */ 991 leave_raw_mode(); 992 993 /* Stop listening for new connections. */ 994 channel_stop_listening(); 995 996 snprintf(string, sizeof string, 997 "%c& [backgrounded]\n", escape_char); 998 buffer_append(berr, string, strlen(string)); 999 1000 /* Fork into background. */ 1001 pid = fork(); 1002 if (pid < 0) { 1003 error("fork: %.100s", strerror(errno)); 1004 continue; 1005 } 1006 if (pid != 0) { /* This is the parent. */ 1007 /* The parent just exits. */ 1008 exit(0); 1009 } 1010 /* The child continues serving connections. */ 1011 if (compat20) { 1012 buffer_append(bin, "\004", 1); 1013 /* fake EOF on stdin */ 1014 return -1; 1015 } else if (!stdin_eof) { 1016 /* 1017 * Sending SSH_CMSG_EOF alone does not 1018 * always appear to be enough. So we 1019 * try to send an EOF character first. 1020 */ 1021 packet_start(SSH_CMSG_STDIN_DATA); 1022 packet_put_string("\004", 1); 1023 packet_send(); 1024 /* Close stdin. */ 1025 stdin_eof = 1; 1026 if (buffer_len(bin) == 0) { 1027 packet_start(SSH_CMSG_EOF); 1028 packet_send(); 1029 } 1030 } 1031 continue; 1032 1033 case '?': 1034 if (c && c->ctl_fd != -1) { 1035 snprintf(string, sizeof string, 1036 "%c?\r\n\ 1037 Supported escape sequences:\r\n\ 1038 %c. - terminate session\r\n\ 1039 %cB - send a BREAK to the remote system\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 } else { 1050 snprintf(string, sizeof string, 1051 "%c?\r\n\ 1052 Supported escape sequences:\r\n\ 1053 %c. - terminate connection (and any multiplexed sessions)\r\n\ 1054 %cB - send a BREAK to the remote system\r\n\ 1055 %cC - open a command line\r\n\ 1056 %cR - Request rekey (SSH protocol 2 only)\r\n\ 1057 %c^Z - suspend ssh\r\n\ 1058 %c# - list forwarded connections\r\n\ 1059 %c& - background ssh (when waiting for connections to terminate)\r\n\ 1060 %c? - this message\r\n\ 1061 %c%c - send the escape character by typing it twice\r\n\ 1062 (Note that escapes are only recognized immediately after newline.)\r\n", 1063 escape_char, escape_char, 1064 escape_char, escape_char, 1065 escape_char, escape_char, 1066 escape_char, escape_char, 1067 escape_char, escape_char, 1068 escape_char); 1069 } 1070 buffer_append(berr, string, strlen(string)); 1071 continue; 1072 1073 case '#': 1074 snprintf(string, sizeof string, "%c#\r\n", 1075 escape_char); 1076 buffer_append(berr, string, strlen(string)); 1077 s = channel_open_message(); 1078 buffer_append(berr, s, strlen(s)); 1079 xfree(s); 1080 continue; 1081 1082 case 'C': 1083 if (c && c->ctl_fd != -1) 1084 goto noescape; 1085 process_cmdline(); 1086 continue; 1087 1088 default: 1089 if (ch != escape_char) { 1090 buffer_put_char(bin, escape_char); 1091 bytes++; 1092 } 1093 /* Escaped characters fall through here */ 1094 break; 1095 } 1096 } else { 1097 /* 1098 * The previous character was not an escape char. 1099 * Check if this is an escape. 1100 */ 1101 if (last_was_cr && ch == escape_char) { 1102 /* 1103 * It is. Set the flag and continue to 1104 * next character. 1105 */ 1106 *escape_pendingp = 1; 1107 continue; 1108 } 1109 } 1110 1111 /* 1112 * Normal character. Record whether it was a newline, 1113 * and append it to the buffer. 1114 */ 1115 last_was_cr = (ch == '\r' || ch == '\n'); 1116 buffer_put_char(bin, ch); 1117 bytes++; 1118 } 1119 return bytes; 1120 } 1121 1122 static void 1123 client_process_input(fd_set *readset) 1124 { 1125 int len; 1126 char buf[8192]; 1127 1128 /* Read input from stdin. */ 1129 if (FD_ISSET(fileno(stdin), readset)) { 1130 /* Read as much as possible. */ 1131 len = read(fileno(stdin), buf, sizeof(buf)); 1132 if (len < 0 && (errno == EAGAIN || errno == EINTR)) 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 len = 0; 1191 else { 1192 /* 1193 * An error or EOF was encountered. Put an 1194 * error message to stderr buffer. 1195 */ 1196 snprintf(buf, sizeof buf, 1197 "write stdout: %.50s\r\n", strerror(errno)); 1198 buffer_append(&stderr_buffer, buf, strlen(buf)); 1199 quit_pending = 1; 1200 return; 1201 } 1202 } 1203 /* Consume printed data from the buffer. */ 1204 buffer_consume(&stdout_buffer, len); 1205 } 1206 /* Write buffered output to stderr. */ 1207 if (FD_ISSET(fileno(stderr), writeset)) { 1208 /* Write as much data as possible. */ 1209 len = write(fileno(stderr), buffer_ptr(&stderr_buffer), 1210 buffer_len(&stderr_buffer)); 1211 if (len <= 0) { 1212 if (errno == EINTR || errno == EAGAIN) 1213 len = 0; 1214 else { 1215 /* 1216 * EOF or error, but can't even print 1217 * error message. 1218 */ 1219 quit_pending = 1; 1220 return; 1221 } 1222 } 1223 /* Consume printed characters from the buffer. */ 1224 buffer_consume(&stderr_buffer, len); 1225 } 1226 } 1227 1228 /* 1229 * Get packets from the connection input buffer, and process them as long as 1230 * there are packets available. 1231 * 1232 * Any unknown packets received during the actual 1233 * session cause the session to terminate. This is 1234 * intended to make debugging easier since no 1235 * confirmations are sent. Any compatible protocol 1236 * extensions must be negotiated during the 1237 * preparatory phase. 1238 */ 1239 1240 static void 1241 client_process_buffered_input_packets(void) 1242 { 1243 dispatch_run(DISPATCH_NONBLOCK, &quit_pending, 1244 compat20 ? xxx_kex : NULL); 1245 } 1246 1247 /* scan buf[] for '~' before sending data to the peer */ 1248 1249 /* Helper: allocate a new escape_filter_ctx and fill in its escape char */ 1250 void * 1251 client_new_escape_filter_ctx(int escape_char) 1252 { 1253 struct escape_filter_ctx *ret; 1254 1255 ret = xmalloc(sizeof(*ret)); 1256 ret->escape_pending = 0; 1257 ret->escape_char = escape_char; 1258 return (void *)ret; 1259 } 1260 1261 /* Free the escape filter context on channel free */ 1262 void 1263 client_filter_cleanup(int cid, void *ctx) 1264 { 1265 xfree(ctx); 1266 } 1267 1268 int 1269 client_simple_escape_filter(Channel *c, char *buf, int len) 1270 { 1271 if (c->extended_usage != CHAN_EXTENDED_WRITE) 1272 return 0; 1273 1274 return process_escapes(c, &c->input, &c->output, &c->extended, 1275 buf, len); 1276 } 1277 1278 static void 1279 client_channel_closed(int id, void *arg) 1280 { 1281 channel_cancel_cleanup(id); 1282 session_closed = 1; 1283 leave_raw_mode(); 1284 } 1285 1286 /* 1287 * Implements the interactive session with the server. This is called after 1288 * the user has been authenticated, and a command has been started on the 1289 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character 1290 * used as an escape character for terminating or suspending the session. 1291 */ 1292 1293 int 1294 client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id) 1295 { 1296 fd_set *readset = NULL, *writeset = NULL; 1297 double start_time, total_time; 1298 int max_fd = 0, max_fd2 = 0, len, rekeying = 0; 1299 u_int64_t ibytes, obytes; 1300 u_int nalloc = 0; 1301 char buf[100]; 1302 1303 debug("Entering interactive session."); 1304 1305 start_time = get_current_time(); 1306 1307 /* Initialize variables. */ 1308 escape_pending1 = 0; 1309 last_was_cr = 1; 1310 exit_status = -1; 1311 stdin_eof = 0; 1312 buffer_high = 64 * 1024; 1313 connection_in = packet_get_connection_in(); 1314 connection_out = packet_get_connection_out(); 1315 max_fd = MAX(connection_in, connection_out); 1316 if (muxserver_sock != -1) 1317 max_fd = MAX(max_fd, muxserver_sock); 1318 1319 if (!compat20) { 1320 /* enable nonblocking unless tty */ 1321 if (!isatty(fileno(stdin))) 1322 set_nonblock(fileno(stdin)); 1323 if (!isatty(fileno(stdout))) 1324 set_nonblock(fileno(stdout)); 1325 if (!isatty(fileno(stderr))) 1326 set_nonblock(fileno(stderr)); 1327 max_fd = MAX(max_fd, fileno(stdin)); 1328 max_fd = MAX(max_fd, fileno(stdout)); 1329 max_fd = MAX(max_fd, fileno(stderr)); 1330 } 1331 quit_pending = 0; 1332 escape_char1 = escape_char_arg; 1333 1334 /* Initialize buffers. */ 1335 buffer_init(&stdin_buffer); 1336 buffer_init(&stdout_buffer); 1337 buffer_init(&stderr_buffer); 1338 1339 client_init_dispatch(); 1340 1341 /* 1342 * Set signal handlers, (e.g. to restore non-blocking mode) 1343 * but don't overwrite SIG_IGN, matches behaviour from rsh(1) 1344 */ 1345 if (signal(SIGHUP, SIG_IGN) != SIG_IGN) 1346 signal(SIGHUP, signal_handler); 1347 if (signal(SIGINT, SIG_IGN) != SIG_IGN) 1348 signal(SIGINT, signal_handler); 1349 if (signal(SIGQUIT, SIG_IGN) != SIG_IGN) 1350 signal(SIGQUIT, signal_handler); 1351 if (signal(SIGTERM, SIG_IGN) != SIG_IGN) 1352 signal(SIGTERM, signal_handler); 1353 signal(SIGWINCH, window_change_handler); 1354 1355 if (have_pty) 1356 enter_raw_mode(); 1357 1358 if (compat20) { 1359 session_ident = ssh2_chan_id; 1360 if (escape_char_arg != SSH_ESCAPECHAR_NONE) 1361 channel_register_filter(session_ident, 1362 client_simple_escape_filter, NULL, 1363 client_filter_cleanup, 1364 client_new_escape_filter_ctx(escape_char_arg)); 1365 if (session_ident != -1) 1366 channel_register_cleanup(session_ident, 1367 client_channel_closed, 0); 1368 } else { 1369 /* Check if we should immediately send eof on stdin. */ 1370 client_check_initial_eof_on_stdin(); 1371 } 1372 1373 /* Main loop of the client for the interactive session mode. */ 1374 while (!quit_pending) { 1375 1376 /* Process buffered packets sent by the server. */ 1377 client_process_buffered_input_packets(); 1378 1379 if (compat20 && session_closed && !channel_still_open()) 1380 break; 1381 1382 rekeying = (xxx_kex != NULL && !xxx_kex->done); 1383 1384 if (rekeying) { 1385 debug("rekeying in progress"); 1386 } else { 1387 /* 1388 * Make packets of buffered stdin data, and buffer 1389 * them for sending to the server. 1390 */ 1391 if (!compat20) 1392 client_make_packets_from_stdin_data(); 1393 1394 /* 1395 * Make packets from buffered channel data, and 1396 * enqueue them for sending to the server. 1397 */ 1398 if (packet_not_very_much_data_to_write()) 1399 channel_output_poll(); 1400 1401 /* 1402 * Check if the window size has changed, and buffer a 1403 * message about it to the server if so. 1404 */ 1405 client_check_window_change(); 1406 1407 if (quit_pending) 1408 break; 1409 } 1410 /* 1411 * Wait until we have something to do (something becomes 1412 * available on one of the descriptors). 1413 */ 1414 max_fd2 = max_fd; 1415 client_wait_until_can_do_something(&readset, &writeset, 1416 &max_fd2, &nalloc, rekeying); 1417 1418 if (quit_pending) 1419 break; 1420 1421 /* Do channel operations unless rekeying in progress. */ 1422 if (!rekeying) { 1423 channel_after_select(readset, writeset); 1424 if (need_rekeying || packet_need_rekeying()) { 1425 debug("need rekeying"); 1426 xxx_kex->done = 0; 1427 kex_send_kexinit(xxx_kex); 1428 need_rekeying = 0; 1429 } 1430 } 1431 1432 /* Buffer input from the connection. */ 1433 client_process_net_input(readset); 1434 1435 /* Accept control connections. */ 1436 if (muxserver_sock != -1 &&FD_ISSET(muxserver_sock, readset)) { 1437 if (muxserver_accept_control()) 1438 quit_pending = 1; 1439 } 1440 1441 if (quit_pending) 1442 break; 1443 1444 if (!compat20) { 1445 /* Buffer data from stdin */ 1446 client_process_input(readset); 1447 /* 1448 * Process output to stdout and stderr. Output to 1449 * the connection is processed elsewhere (above). 1450 */ 1451 client_process_output(writeset); 1452 } 1453 1454 /* 1455 * Send as much buffered packet data as possible to the 1456 * sender. 1457 */ 1458 if (FD_ISSET(connection_out, writeset)) 1459 packet_write_poll(); 1460 } 1461 if (readset) 1462 xfree(readset); 1463 if (writeset) 1464 xfree(writeset); 1465 1466 /* Terminate the session. */ 1467 1468 /* Stop watching for window change. */ 1469 signal(SIGWINCH, SIG_DFL); 1470 1471 channel_free_all(); 1472 1473 if (have_pty) 1474 leave_raw_mode(); 1475 1476 /* restore blocking io */ 1477 if (!isatty(fileno(stdin))) 1478 unset_nonblock(fileno(stdin)); 1479 if (!isatty(fileno(stdout))) 1480 unset_nonblock(fileno(stdout)); 1481 if (!isatty(fileno(stderr))) 1482 unset_nonblock(fileno(stderr)); 1483 1484 /* 1485 * If there was no shell or command requested, there will be no remote 1486 * exit status to be returned. In that case, clear error code if the 1487 * connection was deliberately terminated at this end. 1488 */ 1489 if (no_shell_flag && received_signal == SIGTERM) { 1490 received_signal = 0; 1491 exit_status = 0; 1492 } 1493 1494 if (received_signal) 1495 fatal("Killed by signal %d.", (int) received_signal); 1496 1497 /* 1498 * In interactive mode (with pseudo tty) display a message indicating 1499 * that the connection has been closed. 1500 */ 1501 if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) { 1502 snprintf(buf, sizeof buf, 1503 "Connection to %.64s closed.\r\n", host); 1504 buffer_append(&stderr_buffer, buf, strlen(buf)); 1505 } 1506 1507 /* Output any buffered data for stdout. */ 1508 while (buffer_len(&stdout_buffer) > 0) { 1509 len = write(fileno(stdout), buffer_ptr(&stdout_buffer), 1510 buffer_len(&stdout_buffer)); 1511 if (len <= 0) { 1512 error("Write failed flushing stdout buffer."); 1513 break; 1514 } 1515 buffer_consume(&stdout_buffer, len); 1516 } 1517 1518 /* Output any buffered data for stderr. */ 1519 while (buffer_len(&stderr_buffer) > 0) { 1520 len = write(fileno(stderr), buffer_ptr(&stderr_buffer), 1521 buffer_len(&stderr_buffer)); 1522 if (len <= 0) { 1523 error("Write failed flushing stderr buffer."); 1524 break; 1525 } 1526 buffer_consume(&stderr_buffer, len); 1527 } 1528 1529 /* Clear and free any buffers. */ 1530 memset(buf, 0, sizeof(buf)); 1531 buffer_free(&stdin_buffer); 1532 buffer_free(&stdout_buffer); 1533 buffer_free(&stderr_buffer); 1534 1535 /* Report bytes transferred, and transfer rates. */ 1536 total_time = get_current_time() - start_time; 1537 packet_get_state(MODE_IN, NULL, NULL, NULL, &ibytes); 1538 packet_get_state(MODE_OUT, NULL, NULL, NULL, &obytes); 1539 verbose("Transferred: sent %llu, received %llu bytes, in %.1f seconds", 1540 (unsigned long long)obytes, (unsigned long long)ibytes, total_time); 1541 if (total_time > 0) 1542 verbose("Bytes per second: sent %.1f, received %.1f", 1543 obytes / total_time, ibytes / total_time); 1544 /* Return the exit status of the program. */ 1545 debug("Exit status %d", exit_status); 1546 return exit_status; 1547 } 1548 1549 /*********/ 1550 1551 static void 1552 client_input_stdout_data(int type, u_int32_t seq, void *ctxt) 1553 { 1554 u_int data_len; 1555 char *data = packet_get_string(&data_len); 1556 packet_check_eom(); 1557 buffer_append(&stdout_buffer, data, data_len); 1558 memset(data, 0, data_len); 1559 xfree(data); 1560 } 1561 static void 1562 client_input_stderr_data(int type, u_int32_t seq, void *ctxt) 1563 { 1564 u_int data_len; 1565 char *data = packet_get_string(&data_len); 1566 packet_check_eom(); 1567 buffer_append(&stderr_buffer, data, data_len); 1568 memset(data, 0, data_len); 1569 xfree(data); 1570 } 1571 static void 1572 client_input_exit_status(int type, u_int32_t seq, void *ctxt) 1573 { 1574 exit_status = packet_get_int(); 1575 packet_check_eom(); 1576 /* Acknowledge the exit. */ 1577 packet_start(SSH_CMSG_EXIT_CONFIRMATION); 1578 packet_send(); 1579 /* 1580 * Must wait for packet to be sent since we are 1581 * exiting the loop. 1582 */ 1583 packet_write_wait(); 1584 /* Flag that we want to exit. */ 1585 quit_pending = 1; 1586 } 1587 static void 1588 client_input_agent_open(int type, u_int32_t seq, void *ctxt) 1589 { 1590 Channel *c = NULL; 1591 int remote_id, sock; 1592 1593 /* Read the remote channel number from the message. */ 1594 remote_id = packet_get_int(); 1595 packet_check_eom(); 1596 1597 /* 1598 * Get a connection to the local authentication agent (this may again 1599 * get forwarded). 1600 */ 1601 sock = ssh_get_authentication_socket(); 1602 1603 /* 1604 * If we could not connect the agent, send an error message back to 1605 * the server. This should never happen unless the agent dies, 1606 * because authentication forwarding is only enabled if we have an 1607 * agent. 1608 */ 1609 if (sock >= 0) { 1610 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock, 1611 -1, 0, 0, 0, "authentication agent connection", 1); 1612 c->remote_id = remote_id; 1613 c->force_drain = 1; 1614 } 1615 if (c == NULL) { 1616 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 1617 packet_put_int(remote_id); 1618 } else { 1619 /* Send a confirmation to the remote host. */ 1620 debug("Forwarding authentication connection."); 1621 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); 1622 packet_put_int(remote_id); 1623 packet_put_int(c->self); 1624 } 1625 packet_send(); 1626 } 1627 1628 static Channel * 1629 client_request_forwarded_tcpip(const char *request_type, int rchan) 1630 { 1631 Channel *c = NULL; 1632 char *listen_address, *originator_address; 1633 u_short listen_port, originator_port; 1634 1635 /* Get rest of the packet */ 1636 listen_address = packet_get_string(NULL); 1637 listen_port = packet_get_int(); 1638 originator_address = packet_get_string(NULL); 1639 originator_port = packet_get_int(); 1640 packet_check_eom(); 1641 1642 debug("client_request_forwarded_tcpip: listen %s port %d, " 1643 "originator %s port %d", listen_address, listen_port, 1644 originator_address, originator_port); 1645 1646 c = channel_connect_by_listen_address(listen_port, 1647 "forwarded-tcpip", originator_address); 1648 1649 xfree(originator_address); 1650 xfree(listen_address); 1651 return c; 1652 } 1653 1654 static Channel * 1655 client_request_x11(const char *request_type, int rchan) 1656 { 1657 Channel *c = NULL; 1658 char *originator; 1659 u_short originator_port; 1660 int sock; 1661 1662 if (!options.forward_x11) { 1663 error("Warning: ssh server tried X11 forwarding."); 1664 error("Warning: this is probably a break-in attempt by a " 1665 "malicious server."); 1666 return NULL; 1667 } 1668 originator = packet_get_string(NULL); 1669 if (datafellows & SSH_BUG_X11FWD) { 1670 debug2("buggy server: x11 request w/o originator_port"); 1671 originator_port = 0; 1672 } else { 1673 originator_port = packet_get_int(); 1674 } 1675 packet_check_eom(); 1676 /* XXX check permission */ 1677 debug("client_request_x11: request from %s %d", originator, 1678 originator_port); 1679 xfree(originator); 1680 sock = x11_connect_display(); 1681 if (sock < 0) 1682 return NULL; 1683 /* again is this really necessary for X11? */ 1684 if (options.hpn_disabled) 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 else 1689 c = channel_new("x11", 1690 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1691 options.hpn_buffer_size, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); 1692 c->force_drain = 1; 1693 return c; 1694 } 1695 1696 static Channel * 1697 client_request_agent(const char *request_type, int rchan) 1698 { 1699 Channel *c = NULL; 1700 int sock; 1701 1702 if (!options.forward_agent) { 1703 error("Warning: ssh server tried agent forwarding."); 1704 error("Warning: this is probably a break-in attempt by a " 1705 "malicious server."); 1706 return NULL; 1707 } 1708 sock = ssh_get_authentication_socket(); 1709 if (sock < 0) 1710 return NULL; 1711 if (options.hpn_disabled) 1712 c = channel_new("authentication agent connection", 1713 SSH_CHANNEL_OPEN, sock, sock, -1, 1714 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, 1715 "authentication agent connection", 1); 1716 else 1717 c = channel_new("authentication agent connection", 1718 SSH_CHANNEL_OPEN, sock, sock, -1, 1719 options.hpn_buffer_size, options.hpn_buffer_size, 0, 1720 "authentication agent connection", 1); 1721 c->force_drain = 1; 1722 return c; 1723 } 1724 1725 int 1726 client_request_tun_fwd(int tun_mode, int local_tun, int remote_tun) 1727 { 1728 Channel *c; 1729 int fd; 1730 1731 if (tun_mode == SSH_TUNMODE_NO) 1732 return 0; 1733 1734 if (!compat20) { 1735 error("Tunnel forwarding is not supported for protocol 1"); 1736 return -1; 1737 } 1738 1739 debug("Requesting tun unit %d in mode %d", local_tun, tun_mode); 1740 1741 /* Open local tunnel device */ 1742 if ((fd = tun_open(local_tun, tun_mode)) == -1) { 1743 error("Tunnel device open failed."); 1744 return -1; 1745 } 1746 1747 if(options.hpn_disabled) 1748 c = channel_new("tun", SSH_CHANNEL_OPENING, fd, fd, -1, 1749 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1); 1750 else 1751 c = channel_new("tun", SSH_CHANNEL_OPENING, fd, fd, -1, 1752 options.hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1); 1753 c->datagram = 1; 1754 1755 packet_start(SSH2_MSG_CHANNEL_OPEN); 1756 packet_put_cstring("tun@openssh.com"); 1757 packet_put_int(c->self); 1758 packet_put_int(c->local_window_max); 1759 packet_put_int(c->local_maxpacket); 1760 packet_put_int(tun_mode); 1761 packet_put_int(remote_tun); 1762 packet_send(); 1763 1764 return 0; 1765 } 1766 1767 /* XXXX move to generic input handler */ 1768 static void 1769 client_input_channel_open(int type, u_int32_t seq, void *ctxt) 1770 { 1771 Channel *c = NULL; 1772 char *ctype; 1773 int rchan; 1774 u_int rmaxpack, rwindow, len; 1775 1776 ctype = packet_get_string(&len); 1777 rchan = packet_get_int(); 1778 rwindow = packet_get_int(); 1779 rmaxpack = packet_get_int(); 1780 1781 debug("client_input_channel_open: ctype %s rchan %d win %d max %d", 1782 ctype, rchan, rwindow, rmaxpack); 1783 1784 if (strcmp(ctype, "forwarded-tcpip") == 0) { 1785 c = client_request_forwarded_tcpip(ctype, rchan); 1786 } else if (strcmp(ctype, "x11") == 0) { 1787 c = client_request_x11(ctype, rchan); 1788 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) { 1789 c = client_request_agent(ctype, rchan); 1790 } 1791 /* XXX duplicate : */ 1792 if (c != NULL) { 1793 debug("confirm %s", ctype); 1794 c->remote_id = rchan; 1795 c->remote_window = rwindow; 1796 c->remote_maxpacket = rmaxpack; 1797 if (c->type != SSH_CHANNEL_CONNECTING) { 1798 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); 1799 packet_put_int(c->remote_id); 1800 packet_put_int(c->self); 1801 packet_put_int(c->local_window); 1802 packet_put_int(c->local_maxpacket); 1803 packet_send(); 1804 } 1805 } else { 1806 debug("failure %s", ctype); 1807 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); 1808 packet_put_int(rchan); 1809 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED); 1810 if (!(datafellows & SSH_BUG_OPENFAILURE)) { 1811 packet_put_cstring("open failed"); 1812 packet_put_cstring(""); 1813 } 1814 packet_send(); 1815 } 1816 xfree(ctype); 1817 } 1818 static void 1819 client_input_channel_req(int type, u_int32_t seq, void *ctxt) 1820 { 1821 Channel *c = NULL; 1822 int exitval, id, reply, success = 0; 1823 char *rtype; 1824 1825 id = packet_get_int(); 1826 rtype = packet_get_string(NULL); 1827 reply = packet_get_char(); 1828 1829 debug("client_input_channel_req: channel %d rtype %s reply %d", 1830 id, rtype, reply); 1831 1832 if (id == -1) { 1833 error("client_input_channel_req: request for channel -1"); 1834 } else if ((c = channel_lookup(id)) == NULL) { 1835 error("client_input_channel_req: channel %d: " 1836 "unknown channel", id); 1837 } else if (strcmp(rtype, "eow@openssh.com") == 0) { 1838 packet_check_eom(); 1839 chan_rcvd_eow(c); 1840 } else if (strcmp(rtype, "exit-status") == 0) { 1841 exitval = packet_get_int(); 1842 if (id == session_ident) { 1843 success = 1; 1844 exit_status = exitval; 1845 } else if (c->ctl_fd == -1) { 1846 error("client_input_channel_req: unexpected channel %d", 1847 session_ident); 1848 } else { 1849 atomicio(vwrite, c->ctl_fd, &exitval, sizeof(exitval)); 1850 success = 1; 1851 } 1852 packet_check_eom(); 1853 } 1854 if (reply) { 1855 packet_start(success ? 1856 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE); 1857 packet_put_int(c->remote_id); 1858 packet_send(); 1859 } 1860 xfree(rtype); 1861 } 1862 static void 1863 client_input_global_request(int type, u_int32_t seq, void *ctxt) 1864 { 1865 char *rtype; 1866 int want_reply; 1867 int success = 0; 1868 1869 rtype = packet_get_string(NULL); 1870 want_reply = packet_get_char(); 1871 debug("client_input_global_request: rtype %s want_reply %d", 1872 rtype, want_reply); 1873 if (want_reply) { 1874 packet_start(success ? 1875 SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE); 1876 packet_send(); 1877 packet_write_wait(); 1878 } 1879 xfree(rtype); 1880 } 1881 1882 void 1883 client_session2_setup(int id, int want_tty, int want_subsystem, 1884 const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env) 1885 { 1886 int len; 1887 Channel *c = NULL; 1888 1889 debug2("%s: id %d", __func__, id); 1890 1891 if ((c = channel_lookup(id)) == NULL) 1892 fatal("client_session2_setup: channel %d: unknown channel", id); 1893 1894 if (want_tty) { 1895 struct winsize ws; 1896 1897 /* Store window size in the packet. */ 1898 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0) 1899 memset(&ws, 0, sizeof(ws)); 1900 1901 channel_request_start(id, "pty-req", 1); 1902 client_expect_confirm(id, "PTY allocation", 0); 1903 packet_put_cstring(term != NULL ? term : ""); 1904 packet_put_int((u_int)ws.ws_col); 1905 packet_put_int((u_int)ws.ws_row); 1906 packet_put_int((u_int)ws.ws_xpixel); 1907 packet_put_int((u_int)ws.ws_ypixel); 1908 if (tiop == NULL) 1909 tiop = get_saved_tio(); 1910 tty_make_modes(-1, tiop); 1911 packet_send(); 1912 /* XXX wait for reply */ 1913 c->client_tty = 1; 1914 } 1915 1916 /* Transfer any environment variables from client to server */ 1917 if (options.num_send_env != 0 && env != NULL) { 1918 int i, j, matched; 1919 char *name, *val; 1920 1921 debug("Sending environment."); 1922 for (i = 0; env[i] != NULL; i++) { 1923 /* Split */ 1924 name = xstrdup(env[i]); 1925 if ((val = strchr(name, '=')) == NULL) { 1926 xfree(name); 1927 continue; 1928 } 1929 *val++ = '\0'; 1930 1931 matched = 0; 1932 for (j = 0; j < options.num_send_env; j++) { 1933 if (match_pattern(name, options.send_env[j])) { 1934 matched = 1; 1935 break; 1936 } 1937 } 1938 if (!matched) { 1939 debug3("Ignored env %s", name); 1940 xfree(name); 1941 continue; 1942 } 1943 1944 debug("Sending env %s = %s", name, val); 1945 channel_request_start(id, "env", 0); 1946 packet_put_cstring(name); 1947 packet_put_cstring(val); 1948 packet_send(); 1949 xfree(name); 1950 } 1951 } 1952 1953 len = buffer_len(cmd); 1954 if (len > 0) { 1955 if (len > 900) 1956 len = 900; 1957 if (want_subsystem) { 1958 debug("Sending subsystem: %.*s", 1959 len, (u_char*)buffer_ptr(cmd)); 1960 channel_request_start(id, "subsystem", 1); 1961 client_expect_confirm(id, "subsystem", 1); 1962 } else { 1963 debug("Sending command: %.*s", 1964 len, (u_char*)buffer_ptr(cmd)); 1965 channel_request_start(id, "exec", 1); 1966 client_expect_confirm(id, "exec", 1); 1967 } 1968 packet_put_string(buffer_ptr(cmd), buffer_len(cmd)); 1969 packet_send(); 1970 } else { 1971 channel_request_start(id, "shell", 1); 1972 client_expect_confirm(id, "shell", 1); 1973 packet_send(); 1974 } 1975 } 1976 1977 static void 1978 client_init_dispatch_20(void) 1979 { 1980 dispatch_init(&dispatch_protocol_error); 1981 1982 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); 1983 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); 1984 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); 1985 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); 1986 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open); 1987 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 1988 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 1989 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req); 1990 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); 1991 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm); 1992 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm); 1993 dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request); 1994 1995 /* rekeying */ 1996 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); 1997 1998 /* global request reply messages */ 1999 dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply); 2000 dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply); 2001 } 2002 2003 static void 2004 client_init_dispatch_13(void) 2005 { 2006 dispatch_init(NULL); 2007 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close); 2008 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation); 2009 dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data); 2010 dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 2011 dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 2012 dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open); 2013 dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status); 2014 dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data); 2015 dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data); 2016 2017 dispatch_set(SSH_SMSG_AGENT_OPEN, options.forward_agent ? 2018 &client_input_agent_open : &deny_input_open); 2019 dispatch_set(SSH_SMSG_X11_OPEN, options.forward_x11 ? 2020 &x11_input_open : &deny_input_open); 2021 } 2022 2023 static void 2024 client_init_dispatch_15(void) 2025 { 2026 client_init_dispatch_13(); 2027 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof); 2028 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose); 2029 } 2030 2031 static void 2032 client_init_dispatch(void) 2033 { 2034 if (compat20) 2035 client_init_dispatch_20(); 2036 else if (compat13) 2037 client_init_dispatch_13(); 2038 else 2039 client_init_dispatch_15(); 2040 } 2041 2042 /* client specific fatal cleanup */ 2043 void 2044 cleanup_exit(int i) 2045 { 2046 leave_raw_mode(); 2047 leave_non_blocking(); 2048 if (options.control_path != NULL && muxserver_sock != -1) 2049 unlink(options.control_path); 2050 _exit(i); 2051 } 2052