1 /* $NetBSD: clientloop.c,v 1.3 2009/12/27 01:40:47 christos Exp $ */ 2 /* $OpenBSD: clientloop.c,v 1.213 2009/07/05 19:28:33 stevesk 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 1.3 2009/12/27 01:40:47 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 "roaming.h" 107 #include "getpeereid.h" 108 109 /* import options */ 110 extern Options options; 111 112 /* Flag indicating that stdin should be redirected from /dev/null. */ 113 extern int stdin_null_flag; 114 115 /* Flag indicating that no shell has been requested */ 116 extern int no_shell_flag; 117 118 /* Control socket */ 119 extern int muxserver_sock; 120 121 /* 122 * Name of the host we are connecting to. This is the name given on the 123 * command line, or the HostName specified for the user-supplied name in a 124 * configuration file. 125 */ 126 extern char *host; 127 128 /* 129 * Flag to indicate that we have received a window change signal which has 130 * not yet been processed. This will cause a message indicating the new 131 * window size to be sent to the server a little later. This is volatile 132 * because this is updated in a signal handler. 133 */ 134 static volatile sig_atomic_t received_window_change_signal = 0; 135 static volatile sig_atomic_t received_signal = 0; 136 137 /* Flag indicating whether the user's terminal is in non-blocking mode. */ 138 static int in_non_blocking_mode = 0; 139 140 /* Common data for the client loop code. */ 141 static volatile sig_atomic_t quit_pending; /* Set non-zero to quit the loop. */ 142 static int escape_char1; /* Escape character. (proto1 only) */ 143 static int escape_pending1; /* Last character was an escape (proto1 only) */ 144 static int last_was_cr; /* Last character was a newline. */ 145 static int exit_status; /* Used to store the command exit status. */ 146 static int stdin_eof; /* EOF has been encountered on stderr. */ 147 static Buffer stdin_buffer; /* Buffer for stdin data. */ 148 static Buffer stdout_buffer; /* Buffer for stdout data. */ 149 static Buffer stderr_buffer; /* Buffer for stderr data. */ 150 static u_int buffer_high;/* Soft max buffer size. */ 151 static int connection_in; /* Connection to server (input). */ 152 static int connection_out; /* Connection to server (output). */ 153 static int need_rekeying; /* Set to non-zero if rekeying is requested. */ 154 static int session_closed = 0; /* In SSH2: login session closed. */ 155 156 static void client_init_dispatch(void); 157 int session_ident = -1; 158 159 /* Track escape per proto2 channel */ 160 struct escape_filter_ctx { 161 int escape_pending; 162 int escape_char; 163 }; 164 165 /* Context for channel confirmation replies */ 166 struct channel_reply_ctx { 167 const char *request_type; 168 int id, do_close; 169 }; 170 171 /* Global request success/failure callbacks */ 172 struct global_confirm { 173 TAILQ_ENTRY(global_confirm) entry; 174 global_confirm_cb *cb; 175 void *ctx; 176 int ref_count; 177 }; 178 TAILQ_HEAD(global_confirms, global_confirm); 179 static struct global_confirms global_confirms = 180 TAILQ_HEAD_INITIALIZER(global_confirms); 181 182 /*XXX*/ 183 extern Kex *xxx_kex; 184 185 void ssh_process_session2_setup(int, int, int, Buffer *); 186 187 /* Restores stdin to blocking mode. */ 188 189 static void 190 leave_non_blocking(void) 191 { 192 if (in_non_blocking_mode) { 193 unset_nonblock(fileno(stdin)); 194 in_non_blocking_mode = 0; 195 } 196 } 197 198 /* Puts stdin terminal in non-blocking mode. */ 199 200 static void 201 enter_non_blocking(void) 202 { 203 in_non_blocking_mode = 1; 204 set_nonblock(fileno(stdin)); 205 } 206 207 /* 208 * Signal handler for the window change signal (SIGWINCH). This just sets a 209 * flag indicating that the window has changed. 210 */ 211 /*ARGSUSED */ 212 static void 213 window_change_handler(int sig) 214 { 215 received_window_change_signal = 1; 216 signal(SIGWINCH, window_change_handler); 217 } 218 219 /* 220 * Signal handler for signals that cause the program to terminate. These 221 * signals must be trapped to restore terminal modes. 222 */ 223 /*ARGSUSED */ 224 static void 225 signal_handler(int sig) 226 { 227 received_signal = sig; 228 quit_pending = 1; 229 } 230 231 /* 232 * Returns current time in seconds from Jan 1, 1970 with the maximum 233 * available resolution. 234 */ 235 236 static double 237 get_current_time(void) 238 { 239 struct timeval tv; 240 gettimeofday(&tv, NULL); 241 return (double) tv.tv_sec + (double) tv.tv_usec / 1000000.0; 242 } 243 244 #define SSH_X11_PROTO "MIT-MAGIC-COOKIE-1" 245 void 246 client_x11_get_proto(const char *display, const char *xauth_path, 247 u_int trusted, char **_proto, char **_data) 248 { 249 char cmd[1024]; 250 char line[512]; 251 char xdisplay[512]; 252 static char proto[512], data[512]; 253 FILE *f; 254 int got_data = 0, generated = 0, do_unlink = 0, i; 255 char *xauthdir, *xauthfile; 256 struct stat st; 257 258 xauthdir = xauthfile = NULL; 259 *_proto = proto; 260 *_data = data; 261 proto[0] = data[0] = '\0'; 262 263 if (xauth_path == NULL ||(stat(xauth_path, &st) == -1)) { 264 debug("No xauth program."); 265 } else { 266 if (display == NULL) { 267 debug("x11_get_proto: DISPLAY not set"); 268 return; 269 } 270 /* 271 * Handle FamilyLocal case where $DISPLAY does 272 * not match an authorization entry. For this we 273 * just try "xauth list unix:displaynum.screennum". 274 * XXX: "localhost" match to determine FamilyLocal 275 * is not perfect. 276 */ 277 if (strncmp(display, "localhost:", 10) == 0) { 278 snprintf(xdisplay, sizeof(xdisplay), "unix:%s", 279 display + 10); 280 display = xdisplay; 281 } 282 if (trusted == 0) { 283 xauthdir = xmalloc(MAXPATHLEN); 284 xauthfile = xmalloc(MAXPATHLEN); 285 strlcpy(xauthdir, "/tmp/ssh-XXXXXXXXXX", MAXPATHLEN); 286 if (mkdtemp(xauthdir) != NULL) { 287 do_unlink = 1; 288 snprintf(xauthfile, MAXPATHLEN, "%s/xauthfile", 289 xauthdir); 290 snprintf(cmd, sizeof(cmd), 291 "%s -f %s generate %s " SSH_X11_PROTO 292 " untrusted timeout 1200 2>" _PATH_DEVNULL, 293 xauth_path, xauthfile, display); 294 debug2("x11_get_proto: %s", cmd); 295 if (system(cmd) == 0) 296 generated = 1; 297 } 298 } 299 300 /* 301 * When in untrusted mode, we read the cookie only if it was 302 * successfully generated as an untrusted one in the step 303 * above. 304 */ 305 if (trusted || generated) { 306 snprintf(cmd, sizeof(cmd), 307 "%s %s%s list %s 2>" _PATH_DEVNULL, 308 xauth_path, 309 generated ? "-f " : "" , 310 generated ? xauthfile : "", 311 display); 312 debug2("x11_get_proto: %s", cmd); 313 f = popen(cmd, "r"); 314 if (f && fgets(line, sizeof(line), f) && 315 sscanf(line, "%*s %511s %511s", proto, data) == 2) 316 got_data = 1; 317 if (f) 318 pclose(f); 319 } else 320 error("Warning: untrusted X11 forwarding setup failed: " 321 "xauth key data not generated"); 322 } 323 324 if (do_unlink) { 325 unlink(xauthfile); 326 rmdir(xauthdir); 327 } 328 if (xauthdir) 329 xfree(xauthdir); 330 if (xauthfile) 331 xfree(xauthfile); 332 333 /* 334 * If we didn't get authentication data, just make up some 335 * data. The forwarding code will check the validity of the 336 * response anyway, and substitute this data. The X11 337 * server, however, will ignore this fake data and use 338 * whatever authentication mechanisms it was using otherwise 339 * for the local connection. 340 */ 341 if (!got_data) { 342 u_int32_t rnd = 0; 343 344 logit("Warning: No xauth data; " 345 "using fake authentication data for X11 forwarding."); 346 strlcpy(proto, SSH_X11_PROTO, sizeof proto); 347 for (i = 0; i < 16; i++) { 348 if (i % 4 == 0) 349 rnd = arc4random(); 350 snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", 351 rnd & 0xff); 352 rnd >>= 8; 353 } 354 } 355 } 356 357 /* 358 * This is called when the interactive is entered. This checks if there is 359 * an EOF coming on stdin. We must check this explicitly, as select() does 360 * not appear to wake up when redirecting from /dev/null. 361 */ 362 363 static void 364 client_check_initial_eof_on_stdin(void) 365 { 366 int len; 367 char buf[1]; 368 369 /* 370 * If standard input is to be "redirected from /dev/null", we simply 371 * mark that we have seen an EOF and send an EOF message to the 372 * server. Otherwise, we try to read a single character; it appears 373 * that for some files, such /dev/null, select() never wakes up for 374 * read for this descriptor, which means that we never get EOF. This 375 * way we will get the EOF if stdin comes from /dev/null or similar. 376 */ 377 if (stdin_null_flag) { 378 /* Fake EOF on stdin. */ 379 debug("Sending eof."); 380 stdin_eof = 1; 381 packet_start(SSH_CMSG_EOF); 382 packet_send(); 383 } else { 384 enter_non_blocking(); 385 386 /* Check for immediate EOF on stdin. */ 387 len = read(fileno(stdin), buf, 1); 388 if (len == 0) { 389 /* 390 * EOF. Record that we have seen it and send 391 * EOF to server. 392 */ 393 debug("Sending eof."); 394 stdin_eof = 1; 395 packet_start(SSH_CMSG_EOF); 396 packet_send(); 397 } else if (len > 0) { 398 /* 399 * Got data. We must store the data in the buffer, 400 * and also process it as an escape character if 401 * appropriate. 402 */ 403 if ((u_char) buf[0] == escape_char1) 404 escape_pending1 = 1; 405 else 406 buffer_append(&stdin_buffer, buf, 1); 407 } 408 leave_non_blocking(); 409 } 410 } 411 412 413 /* 414 * Make packets from buffered stdin data, and buffer them for sending to the 415 * connection. 416 */ 417 418 static void 419 client_make_packets_from_stdin_data(void) 420 { 421 u_int len; 422 423 /* Send buffered stdin data to the server. */ 424 while (buffer_len(&stdin_buffer) > 0 && 425 packet_not_very_much_data_to_write()) { 426 len = buffer_len(&stdin_buffer); 427 /* Keep the packets at reasonable size. */ 428 if (len > packet_get_maxsize()) 429 len = packet_get_maxsize(); 430 packet_start(SSH_CMSG_STDIN_DATA); 431 packet_put_string(buffer_ptr(&stdin_buffer), len); 432 packet_send(); 433 buffer_consume(&stdin_buffer, len); 434 /* If we have a pending EOF, send it now. */ 435 if (stdin_eof && buffer_len(&stdin_buffer) == 0) { 436 packet_start(SSH_CMSG_EOF); 437 packet_send(); 438 } 439 } 440 } 441 442 /* 443 * Checks if the client window has changed, and sends a packet about it to 444 * the server if so. The actual change is detected elsewhere (by a software 445 * interrupt on Unix); this just checks the flag and sends a message if 446 * appropriate. 447 */ 448 449 static void 450 client_check_window_change(void) 451 { 452 struct winsize ws; 453 454 if (! received_window_change_signal) 455 return; 456 /** XXX race */ 457 received_window_change_signal = 0; 458 459 debug2("client_check_window_change: changed"); 460 461 if (compat20) { 462 channel_send_window_changes(); 463 } else { 464 if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) 465 return; 466 packet_start(SSH_CMSG_WINDOW_SIZE); 467 packet_put_int((u_int)ws.ws_row); 468 packet_put_int((u_int)ws.ws_col); 469 packet_put_int((u_int)ws.ws_xpixel); 470 packet_put_int((u_int)ws.ws_ypixel); 471 packet_send(); 472 } 473 } 474 475 static void 476 client_global_request_reply(int type, u_int32_t seq, void *ctxt) 477 { 478 struct global_confirm *gc; 479 480 if ((gc = TAILQ_FIRST(&global_confirms)) == NULL) 481 return; 482 if (gc->cb != NULL) 483 gc->cb(type, seq, gc->ctx); 484 if (--gc->ref_count <= 0) { 485 TAILQ_REMOVE(&global_confirms, gc, entry); 486 bzero(gc, sizeof(*gc)); 487 xfree(gc); 488 } 489 490 packet_set_alive_timeouts(0); 491 } 492 493 static void 494 server_alive_check(void) 495 { 496 if (packet_inc_alive_timeouts() > options.server_alive_count_max) { 497 logit("Timeout, server not responding."); 498 cleanup_exit(255); 499 } 500 packet_start(SSH2_MSG_GLOBAL_REQUEST); 501 packet_put_cstring("keepalive@openssh.com"); 502 packet_put_char(1); /* boolean: want reply */ 503 packet_send(); 504 /* Insert an empty placeholder to maintain ordering */ 505 client_register_global_confirm(NULL, NULL); 506 } 507 508 /* 509 * Waits until the client can do something (some data becomes available on 510 * one of the file descriptors). 511 */ 512 static void 513 client_wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, 514 int *maxfdp, u_int *nallocp, int rekeying) 515 { 516 struct timeval tv, *tvp; 517 int ret; 518 519 /* Add any selections by the channel mechanism. */ 520 channel_prepare_select(readsetp, writesetp, maxfdp, nallocp, rekeying); 521 522 if (!compat20) { 523 /* Read from the connection, unless our buffers are full. */ 524 if (buffer_len(&stdout_buffer) < buffer_high && 525 buffer_len(&stderr_buffer) < buffer_high && 526 channel_not_very_much_buffered_data()) 527 FD_SET(connection_in, *readsetp); 528 /* 529 * Read from stdin, unless we have seen EOF or have very much 530 * buffered data to send to the server. 531 */ 532 if (!stdin_eof && packet_not_very_much_data_to_write()) 533 FD_SET(fileno(stdin), *readsetp); 534 535 /* Select stdout/stderr if have data in buffer. */ 536 if (buffer_len(&stdout_buffer) > 0) 537 FD_SET(fileno(stdout), *writesetp); 538 if (buffer_len(&stderr_buffer) > 0) 539 FD_SET(fileno(stderr), *writesetp); 540 } else { 541 /* channel_prepare_select could have closed the last channel */ 542 if (session_closed && !channel_still_open() && 543 !packet_have_data_to_write()) { 544 /* clear mask since we did not call select() */ 545 memset(*readsetp, 0, *nallocp); 546 memset(*writesetp, 0, *nallocp); 547 return; 548 } else { 549 FD_SET(connection_in, *readsetp); 550 } 551 } 552 553 /* Select server connection if have data to write to the server. */ 554 if (packet_have_data_to_write()) 555 FD_SET(connection_out, *writesetp); 556 557 if (muxserver_sock != -1) 558 FD_SET(muxserver_sock, *readsetp); 559 560 /* 561 * Wait for something to happen. This will suspend the process until 562 * some selected descriptor can be read, written, or has some other 563 * event pending. 564 */ 565 566 if (options.server_alive_interval == 0 || !compat20) 567 tvp = NULL; 568 else { 569 tv.tv_sec = options.server_alive_interval; 570 tv.tv_usec = 0; 571 tvp = &tv; 572 } 573 ret = select((*maxfdp)+1, *readsetp, *writesetp, NULL, tvp); 574 if (ret < 0) { 575 char buf[100]; 576 577 /* 578 * We have to clear the select masks, because we return. 579 * We have to return, because the mainloop checks for the flags 580 * set by the signal handlers. 581 */ 582 memset(*readsetp, 0, *nallocp); 583 memset(*writesetp, 0, *nallocp); 584 585 if (errno == EINTR) 586 return; 587 /* Note: we might still have data in the buffers. */ 588 snprintf(buf, sizeof buf, "select: %s\r\n", strerror(errno)); 589 buffer_append(&stderr_buffer, buf, strlen(buf)); 590 quit_pending = 1; 591 } else if (ret == 0) 592 server_alive_check(); 593 } 594 595 static void 596 client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr) 597 { 598 /* Flush stdout and stderr buffers. */ 599 if (buffer_len(bout) > 0) 600 atomicio(vwrite, fileno(stdout), buffer_ptr(bout), 601 buffer_len(bout)); 602 if (buffer_len(berr) > 0) 603 atomicio(vwrite, fileno(stderr), buffer_ptr(berr), 604 buffer_len(berr)); 605 606 leave_raw_mode(); 607 608 /* 609 * Free (and clear) the buffer to reduce the amount of data that gets 610 * written to swap. 611 */ 612 buffer_free(bin); 613 buffer_free(bout); 614 buffer_free(berr); 615 616 /* Send the suspend signal to the program itself. */ 617 kill(getpid(), SIGTSTP); 618 619 /* Reset window sizes in case they have changed */ 620 received_window_change_signal = 1; 621 622 /* OK, we have been continued by the user. Reinitialize buffers. */ 623 buffer_init(bin); 624 buffer_init(bout); 625 buffer_init(berr); 626 627 enter_raw_mode(); 628 } 629 630 static void 631 client_process_net_input(fd_set *readset) 632 { 633 int len, cont = 0; 634 char buf[8192]; 635 636 /* 637 * Read input from the server, and add any such data to the buffer of 638 * the packet subsystem. 639 */ 640 if (FD_ISSET(connection_in, readset)) { 641 /* Read as much as possible. */ 642 len = roaming_read(connection_in, buf, sizeof(buf), &cont); 643 if (len == 0 && cont == 0) { 644 /* 645 * Received EOF. The remote host has closed the 646 * connection. 647 */ 648 snprintf(buf, sizeof buf, 649 "Connection to %.300s closed by remote host.\r\n", 650 host); 651 buffer_append(&stderr_buffer, buf, strlen(buf)); 652 quit_pending = 1; 653 return; 654 } 655 /* 656 * There is a kernel bug on Solaris that causes select to 657 * sometimes wake up even though there is no data available. 658 */ 659 if (len < 0 && (errno == EAGAIN || errno == EINTR)) 660 len = 0; 661 662 if (len < 0) { 663 /* 664 * An error has encountered. Perhaps there is a 665 * network problem. 666 */ 667 snprintf(buf, sizeof buf, 668 "Read from remote host %.300s: %.100s\r\n", 669 host, strerror(errno)); 670 buffer_append(&stderr_buffer, buf, strlen(buf)); 671 quit_pending = 1; 672 return; 673 } 674 packet_process_incoming(buf, len); 675 } 676 } 677 678 static void 679 client_status_confirm(int type, Channel *c, void *ctx) 680 { 681 struct channel_reply_ctx *cr = (struct channel_reply_ctx *)ctx; 682 char errmsg[256]; 683 int tochan; 684 685 /* XXX supress on mux _client_ quietmode */ 686 tochan = options.log_level >= SYSLOG_LEVEL_ERROR && 687 c->ctl_fd != -1 && c->extended_usage == CHAN_EXTENDED_WRITE; 688 689 if (type == SSH2_MSG_CHANNEL_SUCCESS) { 690 debug2("%s request accepted on channel %d", 691 cr->request_type, c->self); 692 } else if (type == SSH2_MSG_CHANNEL_FAILURE) { 693 if (tochan) { 694 snprintf(errmsg, sizeof(errmsg), 695 "%s request failed\r\n", cr->request_type); 696 } else { 697 snprintf(errmsg, sizeof(errmsg), 698 "%s request failed on channel %d", 699 cr->request_type, c->self); 700 } 701 /* If error occurred on primary session channel, then exit */ 702 if (cr->do_close && c->self == session_ident) 703 fatal("%s", errmsg); 704 /* If error occurred on mux client, append to their stderr */ 705 if (tochan) 706 buffer_append(&c->extended, errmsg, strlen(errmsg)); 707 else 708 error("%s", errmsg); 709 if (cr->do_close) { 710 chan_read_failed(c); 711 chan_write_failed(c); 712 } 713 } 714 xfree(cr); 715 } 716 717 static void 718 client_abandon_status_confirm(Channel *c, void *ctx) 719 { 720 xfree(ctx); 721 } 722 723 static void 724 client_expect_confirm(int id, const char *request, int do_close) 725 { 726 struct channel_reply_ctx *cr = xmalloc(sizeof(*cr)); 727 728 cr->request_type = request; 729 cr->do_close = do_close; 730 731 channel_register_status_confirm(id, client_status_confirm, 732 client_abandon_status_confirm, cr); 733 } 734 735 void 736 client_register_global_confirm(global_confirm_cb *cb, void *ctx) 737 { 738 struct global_confirm *gc, *last_gc; 739 740 /* Coalesce identical callbacks */ 741 last_gc = TAILQ_LAST(&global_confirms, global_confirms); 742 if (last_gc && last_gc->cb == cb && last_gc->ctx == ctx) { 743 if (++last_gc->ref_count >= INT_MAX) 744 fatal("%s: last_gc->ref_count = %d", 745 __func__, last_gc->ref_count); 746 return; 747 } 748 749 gc = xmalloc(sizeof(*gc)); 750 gc->cb = cb; 751 gc->ctx = ctx; 752 gc->ref_count = 1; 753 TAILQ_INSERT_TAIL(&global_confirms, gc, entry); 754 } 755 756 static void 757 process_cmdline(void) 758 { 759 void (*handler)(int); 760 char *s, *cmd, *cancel_host; 761 int delete = 0; 762 int local = 0, remote = 0, dynamic = 0; 763 int cancel_port; 764 Forward fwd; 765 766 bzero(&fwd, sizeof(fwd)); 767 fwd.listen_host = fwd.connect_host = NULL; 768 769 leave_raw_mode(); 770 handler = signal(SIGINT, SIG_IGN); 771 cmd = s = read_passphrase("\r\nssh> ", RP_ECHO); 772 if (s == NULL) 773 goto out; 774 while (isspace((unsigned char)*s)) 775 s++; 776 if (*s == '-') 777 s++; /* Skip cmdline '-', if any */ 778 if (*s == '\0') 779 goto out; 780 781 if (*s == 'h' || *s == 'H' || *s == '?') { 782 logit("Commands:"); 783 logit(" -L[bind_address:]port:host:hostport " 784 "Request local forward"); 785 logit(" -R[bind_address:]port:host:hostport " 786 "Request remote forward"); 787 logit(" -D[bind_address:]port " 788 "Request dynamic forward"); 789 logit(" -KR[bind_address:]port " 790 "Cancel remote forward"); 791 if (!options.permit_local_command) 792 goto out; 793 logit(" !args " 794 "Execute local command"); 795 goto out; 796 } 797 798 if (*s == '!' && options.permit_local_command) { 799 s++; 800 ssh_local_cmd(s); 801 goto out; 802 } 803 804 if (*s == 'K') { 805 delete = 1; 806 s++; 807 } 808 if (*s == 'L') 809 local = 1; 810 else if (*s == 'R') 811 remote = 1; 812 else if (*s == 'D') 813 dynamic = 1; 814 else { 815 logit("Invalid command."); 816 goto out; 817 } 818 819 if ((local || dynamic) && delete) { 820 logit("Not supported."); 821 goto out; 822 } 823 if (remote && delete && !compat20) { 824 logit("Not supported for SSH protocol version 1."); 825 goto out; 826 } 827 828 s++; 829 while (isspace((unsigned char)*s)) 830 s++; 831 832 if (delete) { 833 cancel_port = 0; 834 cancel_host = hpdelim(&s); /* may be NULL */ 835 if (s != NULL) { 836 cancel_port = a2port(s); 837 cancel_host = cleanhostname(cancel_host); 838 } else { 839 cancel_port = a2port(cancel_host); 840 cancel_host = NULL; 841 } 842 if (cancel_port <= 0) { 843 logit("Bad forwarding close port"); 844 goto out; 845 } 846 channel_request_rforward_cancel(cancel_host, cancel_port); 847 } else { 848 if (!parse_forward(&fwd, s, dynamic, remote)) { 849 logit("Bad forwarding specification."); 850 goto out; 851 } 852 if (local || dynamic) { 853 if (channel_setup_local_fwd_listener(fwd.listen_host, 854 fwd.listen_port, fwd.connect_host, 855 fwd.connect_port, options.gateway_ports) < 0) { 856 logit("Port forwarding failed."); 857 goto out; 858 } 859 } else { 860 if (channel_request_remote_forwarding(fwd.listen_host, 861 fwd.listen_port, fwd.connect_host, 862 fwd.connect_port) < 0) { 863 logit("Port forwarding failed."); 864 goto out; 865 } 866 } 867 868 logit("Forwarding port."); 869 } 870 871 out: 872 signal(SIGINT, handler); 873 enter_raw_mode(); 874 if (cmd) 875 xfree(cmd); 876 if (fwd.listen_host != NULL) 877 xfree(fwd.listen_host); 878 if (fwd.connect_host != NULL) 879 xfree(fwd.connect_host); 880 } 881 882 /* 883 * Process the characters one by one, call with c==NULL for proto1 case. 884 */ 885 static int 886 process_escapes(Channel *c, Buffer *bin, Buffer *bout, Buffer *berr, 887 char *buf, int len) 888 { 889 char string[1024]; 890 pid_t pid; 891 int bytes = 0; 892 u_int i; 893 u_char ch; 894 char *s; 895 int *escape_pendingp, escape_char; 896 struct escape_filter_ctx *efc; 897 898 if (c == NULL) { 899 escape_pendingp = &escape_pending1; 900 escape_char = escape_char1; 901 } else { 902 if (c->filter_ctx == NULL) 903 return 0; 904 efc = (struct escape_filter_ctx *)c->filter_ctx; 905 escape_pendingp = &efc->escape_pending; 906 escape_char = efc->escape_char; 907 } 908 909 if (len <= 0) 910 return (0); 911 912 for (i = 0; i < (u_int)len; i++) { 913 /* Get one character at a time. */ 914 ch = buf[i]; 915 916 if (*escape_pendingp) { 917 /* We have previously seen an escape character. */ 918 /* Clear the flag now. */ 919 *escape_pendingp = 0; 920 921 /* Process the escaped character. */ 922 switch (ch) { 923 case '.': 924 /* Terminate the connection. */ 925 snprintf(string, sizeof string, "%c.\r\n", 926 escape_char); 927 buffer_append(berr, string, strlen(string)); 928 929 if (c && c->ctl_fd != -1) { 930 chan_read_failed(c); 931 chan_write_failed(c); 932 return 0; 933 } else 934 quit_pending = 1; 935 return -1; 936 937 case 'Z' - 64: 938 /* XXX support this for mux clients */ 939 if (c && c->ctl_fd != -1) { 940 noescape: 941 snprintf(string, sizeof string, 942 "%c%c escape not available to " 943 "multiplexed sessions\r\n", 944 escape_char, ch); 945 buffer_append(berr, string, 946 strlen(string)); 947 continue; 948 } 949 /* Suspend the program. Inform the user */ 950 snprintf(string, sizeof string, 951 "%c^Z [suspend ssh]\r\n", escape_char); 952 buffer_append(berr, string, strlen(string)); 953 954 /* Restore terminal modes and suspend. */ 955 client_suspend_self(bin, bout, berr); 956 957 /* We have been continued. */ 958 continue; 959 960 case 'B': 961 if (compat20) { 962 snprintf(string, sizeof string, 963 "%cB\r\n", escape_char); 964 buffer_append(berr, string, 965 strlen(string)); 966 channel_request_start(session_ident, 967 "break", 0); 968 packet_put_int(1000); 969 packet_send(); 970 } 971 continue; 972 973 case 'R': 974 if (compat20) { 975 if (datafellows & SSH_BUG_NOREKEY) 976 logit("Server does not " 977 "support re-keying"); 978 else 979 need_rekeying = 1; 980 } 981 continue; 982 983 case '&': 984 if (c && c->ctl_fd != -1) 985 goto noescape; 986 /* 987 * Detach the program (continue to serve 988 * connections, but put in background and no 989 * more new connections). 990 */ 991 /* Restore tty modes. */ 992 leave_raw_mode(); 993 994 /* Stop listening for new connections. */ 995 channel_stop_listening(); 996 997 snprintf(string, sizeof string, 998 "%c& [backgrounded]\n", escape_char); 999 buffer_append(berr, string, strlen(string)); 1000 1001 /* Fork into background. */ 1002 pid = fork(); 1003 if (pid < 0) { 1004 error("fork: %.100s", strerror(errno)); 1005 continue; 1006 } 1007 if (pid != 0) { /* This is the parent. */ 1008 /* The parent just exits. */ 1009 exit(0); 1010 } 1011 /* The child continues serving connections. */ 1012 if (compat20) { 1013 buffer_append(bin, "\004", 1); 1014 /* fake EOF on stdin */ 1015 return -1; 1016 } else if (!stdin_eof) { 1017 /* 1018 * Sending SSH_CMSG_EOF alone does not 1019 * always appear to be enough. So we 1020 * try to send an EOF character first. 1021 */ 1022 packet_start(SSH_CMSG_STDIN_DATA); 1023 packet_put_string("\004", 1); 1024 packet_send(); 1025 /* Close stdin. */ 1026 stdin_eof = 1; 1027 if (buffer_len(bin) == 0) { 1028 packet_start(SSH_CMSG_EOF); 1029 packet_send(); 1030 } 1031 } 1032 continue; 1033 1034 case '?': 1035 if (c && c->ctl_fd != -1) { 1036 snprintf(string, sizeof string, 1037 "%c?\r\n\ 1038 Supported escape sequences:\r\n\ 1039 %c. - terminate session\r\n\ 1040 %cB - send a BREAK to the remote system\r\n\ 1041 %cR - Request rekey (SSH protocol 2 only)\r\n\ 1042 %c# - list forwarded connections\r\n\ 1043 %c? - this message\r\n\ 1044 %c%c - send the escape character by typing it twice\r\n\ 1045 (Note that escapes are only recognized immediately after newline.)\r\n", 1046 escape_char, escape_char, 1047 escape_char, escape_char, 1048 escape_char, escape_char, 1049 escape_char, escape_char); 1050 } else { 1051 snprintf(string, sizeof string, 1052 "%c?\r\n\ 1053 Supported escape sequences:\r\n\ 1054 %c. - terminate connection (and any multiplexed sessions)\r\n\ 1055 %cB - send a BREAK to the remote system\r\n\ 1056 %cC - open a command line\r\n\ 1057 %cR - Request rekey (SSH protocol 2 only)\r\n\ 1058 %c^Z - suspend ssh\r\n\ 1059 %c# - list forwarded connections\r\n\ 1060 %c& - background ssh (when waiting for connections to terminate)\r\n\ 1061 %c? - this message\r\n\ 1062 %c%c - send the escape character by typing it twice\r\n\ 1063 (Note that escapes are only recognized immediately after newline.)\r\n", 1064 escape_char, escape_char, 1065 escape_char, escape_char, 1066 escape_char, escape_char, 1067 escape_char, escape_char, 1068 escape_char, escape_char, 1069 escape_char); 1070 } 1071 buffer_append(berr, string, strlen(string)); 1072 continue; 1073 1074 case '#': 1075 snprintf(string, sizeof string, "%c#\r\n", 1076 escape_char); 1077 buffer_append(berr, string, strlen(string)); 1078 s = channel_open_message(); 1079 buffer_append(berr, s, strlen(s)); 1080 xfree(s); 1081 continue; 1082 1083 case 'C': 1084 if (c && c->ctl_fd != -1) 1085 goto noescape; 1086 process_cmdline(); 1087 continue; 1088 1089 default: 1090 if (ch != escape_char) { 1091 buffer_put_char(bin, escape_char); 1092 bytes++; 1093 } 1094 /* Escaped characters fall through here */ 1095 break; 1096 } 1097 } else { 1098 /* 1099 * The previous character was not an escape char. 1100 * Check if this is an escape. 1101 */ 1102 if (last_was_cr && ch == escape_char) { 1103 /* 1104 * It is. Set the flag and continue to 1105 * next character. 1106 */ 1107 *escape_pendingp = 1; 1108 continue; 1109 } 1110 } 1111 1112 /* 1113 * Normal character. Record whether it was a newline, 1114 * and append it to the buffer. 1115 */ 1116 last_was_cr = (ch == '\r' || ch == '\n'); 1117 buffer_put_char(bin, ch); 1118 bytes++; 1119 } 1120 return bytes; 1121 } 1122 1123 static void 1124 client_process_input(fd_set *readset) 1125 { 1126 int len; 1127 char buf[8192]; 1128 1129 /* Read input from stdin. */ 1130 if (FD_ISSET(fileno(stdin), readset)) { 1131 /* Read as much as possible. */ 1132 len = read(fileno(stdin), buf, sizeof(buf)); 1133 if (len < 0 && (errno == EAGAIN || errno == EINTR)) 1134 return; /* we'll try again later */ 1135 if (len <= 0) { 1136 /* 1137 * Received EOF or error. They are treated 1138 * similarly, except that an error message is printed 1139 * if it was an error condition. 1140 */ 1141 if (len < 0) { 1142 snprintf(buf, sizeof buf, "read: %.100s\r\n", 1143 strerror(errno)); 1144 buffer_append(&stderr_buffer, buf, strlen(buf)); 1145 } 1146 /* Mark that we have seen EOF. */ 1147 stdin_eof = 1; 1148 /* 1149 * Send an EOF message to the server unless there is 1150 * data in the buffer. If there is data in the 1151 * buffer, no message will be sent now. Code 1152 * elsewhere will send the EOF when the buffer 1153 * becomes empty if stdin_eof is set. 1154 */ 1155 if (buffer_len(&stdin_buffer) == 0) { 1156 packet_start(SSH_CMSG_EOF); 1157 packet_send(); 1158 } 1159 } else if (escape_char1 == SSH_ESCAPECHAR_NONE) { 1160 /* 1161 * Normal successful read, and no escape character. 1162 * Just append the data to buffer. 1163 */ 1164 buffer_append(&stdin_buffer, buf, len); 1165 } else { 1166 /* 1167 * Normal, successful read. But we have an escape 1168 * character and have to process the characters one 1169 * by one. 1170 */ 1171 if (process_escapes(NULL, &stdin_buffer, 1172 &stdout_buffer, &stderr_buffer, buf, len) == -1) 1173 return; 1174 } 1175 } 1176 } 1177 1178 static void 1179 client_process_output(fd_set *writeset) 1180 { 1181 int len; 1182 char buf[100]; 1183 1184 /* Write buffered output to stdout. */ 1185 if (FD_ISSET(fileno(stdout), writeset)) { 1186 /* Write as much data as possible. */ 1187 len = write(fileno(stdout), buffer_ptr(&stdout_buffer), 1188 buffer_len(&stdout_buffer)); 1189 if (len <= 0) { 1190 if (errno == EINTR || errno == EAGAIN) 1191 len = 0; 1192 else { 1193 /* 1194 * An error or EOF was encountered. Put an 1195 * error message to stderr buffer. 1196 */ 1197 snprintf(buf, sizeof buf, 1198 "write stdout: %.50s\r\n", strerror(errno)); 1199 buffer_append(&stderr_buffer, buf, strlen(buf)); 1200 quit_pending = 1; 1201 return; 1202 } 1203 } 1204 /* Consume printed data from the buffer. */ 1205 buffer_consume(&stdout_buffer, len); 1206 } 1207 /* Write buffered output to stderr. */ 1208 if (FD_ISSET(fileno(stderr), writeset)) { 1209 /* Write as much data as possible. */ 1210 len = write(fileno(stderr), buffer_ptr(&stderr_buffer), 1211 buffer_len(&stderr_buffer)); 1212 if (len <= 0) { 1213 if (errno == EINTR || errno == EAGAIN) 1214 len = 0; 1215 else { 1216 /* 1217 * EOF or error, but can't even print 1218 * error message. 1219 */ 1220 quit_pending = 1; 1221 return; 1222 } 1223 } 1224 /* Consume printed characters from the buffer. */ 1225 buffer_consume(&stderr_buffer, len); 1226 } 1227 } 1228 1229 /* 1230 * Get packets from the connection input buffer, and process them as long as 1231 * there are packets available. 1232 * 1233 * Any unknown packets received during the actual 1234 * session cause the session to terminate. This is 1235 * intended to make debugging easier since no 1236 * confirmations are sent. Any compatible protocol 1237 * extensions must be negotiated during the 1238 * preparatory phase. 1239 */ 1240 1241 static void 1242 client_process_buffered_input_packets(void) 1243 { 1244 dispatch_run(DISPATCH_NONBLOCK, &quit_pending, 1245 compat20 ? xxx_kex : NULL); 1246 } 1247 1248 /* scan buf[] for '~' before sending data to the peer */ 1249 1250 /* Helper: allocate a new escape_filter_ctx and fill in its escape char */ 1251 void * 1252 client_new_escape_filter_ctx(int escape_char) 1253 { 1254 struct escape_filter_ctx *ret; 1255 1256 ret = xmalloc(sizeof(*ret)); 1257 ret->escape_pending = 0; 1258 ret->escape_char = escape_char; 1259 return (void *)ret; 1260 } 1261 1262 /* Free the escape filter context on channel free */ 1263 void 1264 client_filter_cleanup(int cid, void *ctx) 1265 { 1266 xfree(ctx); 1267 } 1268 1269 int 1270 client_simple_escape_filter(Channel *c, char *buf, int len) 1271 { 1272 if (c->extended_usage != CHAN_EXTENDED_WRITE) 1273 return 0; 1274 1275 return process_escapes(c, &c->input, &c->output, &c->extended, 1276 buf, len); 1277 } 1278 1279 static void 1280 client_channel_closed(int id, void *arg) 1281 { 1282 channel_cancel_cleanup(id); 1283 session_closed = 1; 1284 leave_raw_mode(); 1285 } 1286 1287 /* 1288 * Implements the interactive session with the server. This is called after 1289 * the user has been authenticated, and a command has been started on the 1290 * remote host. If escape_char != SSH_ESCAPECHAR_NONE, it is the character 1291 * used as an escape character for terminating or suspending the session. 1292 */ 1293 1294 int 1295 client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id) 1296 { 1297 fd_set *readset = NULL, *writeset = NULL; 1298 double start_time, total_time; 1299 int max_fd = 0, max_fd2 = 0, len, rekeying = 0; 1300 u_int64_t ibytes, obytes; 1301 u_int nalloc = 0; 1302 char buf[100]; 1303 1304 debug("Entering interactive session."); 1305 1306 start_time = get_current_time(); 1307 1308 /* Initialize variables. */ 1309 escape_pending1 = 0; 1310 last_was_cr = 1; 1311 exit_status = -1; 1312 stdin_eof = 0; 1313 buffer_high = 64 * 1024; 1314 connection_in = packet_get_connection_in(); 1315 connection_out = packet_get_connection_out(); 1316 max_fd = MAX(connection_in, connection_out); 1317 if (muxserver_sock != -1) 1318 max_fd = MAX(max_fd, muxserver_sock); 1319 1320 if (!compat20) { 1321 /* enable nonblocking unless tty */ 1322 if (!isatty(fileno(stdin))) 1323 set_nonblock(fileno(stdin)); 1324 if (!isatty(fileno(stdout))) 1325 set_nonblock(fileno(stdout)); 1326 if (!isatty(fileno(stderr))) 1327 set_nonblock(fileno(stderr)); 1328 max_fd = MAX(max_fd, fileno(stdin)); 1329 max_fd = MAX(max_fd, fileno(stdout)); 1330 max_fd = MAX(max_fd, fileno(stderr)); 1331 } 1332 quit_pending = 0; 1333 escape_char1 = escape_char_arg; 1334 1335 /* Initialize buffers. */ 1336 buffer_init(&stdin_buffer); 1337 buffer_init(&stdout_buffer); 1338 buffer_init(&stderr_buffer); 1339 1340 client_init_dispatch(); 1341 1342 /* 1343 * Set signal handlers, (e.g. to restore non-blocking mode) 1344 * but don't overwrite SIG_IGN, matches behaviour from rsh(1) 1345 */ 1346 if (signal(SIGHUP, SIG_IGN) != SIG_IGN) 1347 signal(SIGHUP, signal_handler); 1348 if (signal(SIGINT, SIG_IGN) != SIG_IGN) 1349 signal(SIGINT, signal_handler); 1350 if (signal(SIGQUIT, SIG_IGN) != SIG_IGN) 1351 signal(SIGQUIT, signal_handler); 1352 if (signal(SIGTERM, SIG_IGN) != SIG_IGN) 1353 signal(SIGTERM, signal_handler); 1354 signal(SIGWINCH, window_change_handler); 1355 1356 if (have_pty) 1357 enter_raw_mode(); 1358 1359 if (compat20) { 1360 session_ident = ssh2_chan_id; 1361 if (escape_char_arg != SSH_ESCAPECHAR_NONE) 1362 channel_register_filter(session_ident, 1363 client_simple_escape_filter, NULL, 1364 client_filter_cleanup, 1365 client_new_escape_filter_ctx(escape_char_arg)); 1366 if (session_ident != -1) 1367 channel_register_cleanup(session_ident, 1368 client_channel_closed, 0); 1369 } else { 1370 /* Check if we should immediately send eof on stdin. */ 1371 client_check_initial_eof_on_stdin(); 1372 } 1373 1374 /* Main loop of the client for the interactive session mode. */ 1375 while (!quit_pending) { 1376 1377 /* Process buffered packets sent by the server. */ 1378 client_process_buffered_input_packets(); 1379 1380 if (compat20 && session_closed && !channel_still_open()) 1381 break; 1382 1383 rekeying = (xxx_kex != NULL && !xxx_kex->done); 1384 1385 if (rekeying) { 1386 debug("rekeying in progress"); 1387 } else { 1388 /* 1389 * Make packets of buffered stdin data, and buffer 1390 * them for sending to the server. 1391 */ 1392 if (!compat20) 1393 client_make_packets_from_stdin_data(); 1394 1395 /* 1396 * Make packets from buffered channel data, and 1397 * enqueue them for sending to the server. 1398 */ 1399 if (packet_not_very_much_data_to_write()) 1400 channel_output_poll(); 1401 1402 /* 1403 * Check if the window size has changed, and buffer a 1404 * message about it to the server if so. 1405 */ 1406 client_check_window_change(); 1407 1408 if (quit_pending) 1409 break; 1410 } 1411 /* 1412 * Wait until we have something to do (something becomes 1413 * available on one of the descriptors). 1414 */ 1415 max_fd2 = max_fd; 1416 client_wait_until_can_do_something(&readset, &writeset, 1417 &max_fd2, &nalloc, rekeying); 1418 1419 if (quit_pending) 1420 break; 1421 1422 /* Do channel operations unless rekeying in progress. */ 1423 if (!rekeying) { 1424 channel_after_select(readset, writeset); 1425 if (need_rekeying || packet_need_rekeying()) { 1426 debug("need rekeying"); 1427 xxx_kex->done = 0; 1428 kex_send_kexinit(xxx_kex); 1429 need_rekeying = 0; 1430 } 1431 } 1432 1433 /* Buffer input from the connection. */ 1434 client_process_net_input(readset); 1435 1436 /* Accept control connections. */ 1437 if (muxserver_sock != -1 &&FD_ISSET(muxserver_sock, readset)) { 1438 if (muxserver_accept_control()) 1439 quit_pending = 1; 1440 } 1441 1442 if (quit_pending) 1443 break; 1444 1445 if (!compat20) { 1446 /* Buffer data from stdin */ 1447 client_process_input(readset); 1448 /* 1449 * Process output to stdout and stderr. Output to 1450 * the connection is processed elsewhere (above). 1451 */ 1452 client_process_output(writeset); 1453 } 1454 1455 /* 1456 * Send as much buffered packet data as possible to the 1457 * sender. 1458 */ 1459 if (FD_ISSET(connection_out, writeset)) 1460 packet_write_poll(); 1461 } 1462 if (readset) 1463 xfree(readset); 1464 if (writeset) 1465 xfree(writeset); 1466 1467 /* Terminate the session. */ 1468 1469 /* Stop watching for window change. */ 1470 signal(SIGWINCH, SIG_DFL); 1471 1472 if (compat20) { 1473 packet_start(SSH2_MSG_DISCONNECT); 1474 packet_put_int(SSH2_DISCONNECT_BY_APPLICATION); 1475 packet_put_cstring("disconnected by user"); 1476 packet_send(); 1477 packet_write_wait(); 1478 } 1479 1480 channel_free_all(); 1481 1482 if (have_pty) 1483 leave_raw_mode(); 1484 1485 /* restore blocking io */ 1486 if (!isatty(fileno(stdin))) 1487 unset_nonblock(fileno(stdin)); 1488 if (!isatty(fileno(stdout))) 1489 unset_nonblock(fileno(stdout)); 1490 if (!isatty(fileno(stderr))) 1491 unset_nonblock(fileno(stderr)); 1492 1493 /* 1494 * If there was no shell or command requested, there will be no remote 1495 * exit status to be returned. In that case, clear error code if the 1496 * connection was deliberately terminated at this end. 1497 */ 1498 if (no_shell_flag && received_signal == SIGTERM) { 1499 received_signal = 0; 1500 exit_status = 0; 1501 } 1502 1503 if (received_signal) 1504 fatal("Killed by signal %d.", (int) received_signal); 1505 1506 /* 1507 * In interactive mode (with pseudo tty) display a message indicating 1508 * that the connection has been closed. 1509 */ 1510 if (have_pty && options.log_level != SYSLOG_LEVEL_QUIET) { 1511 snprintf(buf, sizeof buf, 1512 "Connection to %.64s closed.\r\n", host); 1513 buffer_append(&stderr_buffer, buf, strlen(buf)); 1514 } 1515 1516 /* Output any buffered data for stdout. */ 1517 while (buffer_len(&stdout_buffer) > 0) { 1518 len = write(fileno(stdout), buffer_ptr(&stdout_buffer), 1519 buffer_len(&stdout_buffer)); 1520 if (len <= 0) { 1521 error("Write failed flushing stdout buffer."); 1522 break; 1523 } 1524 buffer_consume(&stdout_buffer, len); 1525 } 1526 1527 /* Output any buffered data for stderr. */ 1528 while (buffer_len(&stderr_buffer) > 0) { 1529 len = write(fileno(stderr), buffer_ptr(&stderr_buffer), 1530 buffer_len(&stderr_buffer)); 1531 if (len <= 0) { 1532 error("Write failed flushing stderr buffer."); 1533 break; 1534 } 1535 buffer_consume(&stderr_buffer, len); 1536 } 1537 1538 /* Clear and free any buffers. */ 1539 memset(buf, 0, sizeof(buf)); 1540 buffer_free(&stdin_buffer); 1541 buffer_free(&stdout_buffer); 1542 buffer_free(&stderr_buffer); 1543 1544 /* Report bytes transferred, and transfer rates. */ 1545 total_time = get_current_time() - start_time; 1546 packet_get_state(MODE_IN, NULL, NULL, NULL, &ibytes); 1547 packet_get_state(MODE_OUT, NULL, NULL, NULL, &obytes); 1548 verbose("Transferred: sent %llu, received %llu bytes, in %.1f seconds", 1549 (unsigned long long)obytes, (unsigned long long)ibytes, total_time); 1550 if (total_time > 0) 1551 verbose("Bytes per second: sent %.1f, received %.1f", 1552 obytes / total_time, ibytes / total_time); 1553 /* Return the exit status of the program. */ 1554 debug("Exit status %d", exit_status); 1555 return exit_status; 1556 } 1557 1558 /*********/ 1559 1560 static void 1561 client_input_stdout_data(int type, u_int32_t seq, void *ctxt) 1562 { 1563 u_int data_len; 1564 char *data = packet_get_string(&data_len); 1565 packet_check_eom(); 1566 buffer_append(&stdout_buffer, data, data_len); 1567 memset(data, 0, data_len); 1568 xfree(data); 1569 } 1570 static void 1571 client_input_stderr_data(int type, u_int32_t seq, void *ctxt) 1572 { 1573 u_int data_len; 1574 char *data = packet_get_string(&data_len); 1575 packet_check_eom(); 1576 buffer_append(&stderr_buffer, data, data_len); 1577 memset(data, 0, data_len); 1578 xfree(data); 1579 } 1580 static void 1581 client_input_exit_status(int type, u_int32_t seq, void *ctxt) 1582 { 1583 exit_status = packet_get_int(); 1584 packet_check_eom(); 1585 /* Acknowledge the exit. */ 1586 packet_start(SSH_CMSG_EXIT_CONFIRMATION); 1587 packet_send(); 1588 /* 1589 * Must wait for packet to be sent since we are 1590 * exiting the loop. 1591 */ 1592 packet_write_wait(); 1593 /* Flag that we want to exit. */ 1594 quit_pending = 1; 1595 } 1596 static void 1597 client_input_agent_open(int type, u_int32_t seq, void *ctxt) 1598 { 1599 Channel *c = NULL; 1600 int remote_id, sock; 1601 1602 /* Read the remote channel number from the message. */ 1603 remote_id = packet_get_int(); 1604 packet_check_eom(); 1605 1606 /* 1607 * Get a connection to the local authentication agent (this may again 1608 * get forwarded). 1609 */ 1610 sock = ssh_get_authentication_socket(); 1611 1612 /* 1613 * If we could not connect the agent, send an error message back to 1614 * the server. This should never happen unless the agent dies, 1615 * because authentication forwarding is only enabled if we have an 1616 * agent. 1617 */ 1618 if (sock >= 0) { 1619 c = channel_new("", SSH_CHANNEL_OPEN, sock, sock, 1620 -1, 0, 0, 0, "authentication agent connection", 1); 1621 c->remote_id = remote_id; 1622 c->force_drain = 1; 1623 } 1624 if (c == NULL) { 1625 packet_start(SSH_MSG_CHANNEL_OPEN_FAILURE); 1626 packet_put_int(remote_id); 1627 } else { 1628 /* Send a confirmation to the remote host. */ 1629 debug("Forwarding authentication connection."); 1630 packet_start(SSH_MSG_CHANNEL_OPEN_CONFIRMATION); 1631 packet_put_int(remote_id); 1632 packet_put_int(c->self); 1633 } 1634 packet_send(); 1635 } 1636 1637 static Channel * 1638 client_request_forwarded_tcpip(const char *request_type, int rchan) 1639 { 1640 Channel *c = NULL; 1641 char *listen_address, *originator_address; 1642 u_short listen_port, originator_port; 1643 1644 /* Get rest of the packet */ 1645 listen_address = packet_get_string(NULL); 1646 listen_port = packet_get_int(); 1647 originator_address = packet_get_string(NULL); 1648 originator_port = packet_get_int(); 1649 packet_check_eom(); 1650 1651 debug("client_request_forwarded_tcpip: listen %s port %d, " 1652 "originator %s port %d", listen_address, listen_port, 1653 originator_address, originator_port); 1654 1655 c = channel_connect_by_listen_address(listen_port, 1656 "forwarded-tcpip", originator_address); 1657 1658 xfree(originator_address); 1659 xfree(listen_address); 1660 return c; 1661 } 1662 1663 static Channel * 1664 client_request_x11(const char *request_type, int rchan) 1665 { 1666 Channel *c = NULL; 1667 char *originator; 1668 u_short originator_port; 1669 int sock; 1670 1671 if (!options.forward_x11) { 1672 error("Warning: ssh server tried X11 forwarding."); 1673 error("Warning: this is probably a break-in attempt by a " 1674 "malicious server."); 1675 return NULL; 1676 } 1677 originator = packet_get_string(NULL); 1678 if (datafellows & SSH_BUG_X11FWD) { 1679 debug2("buggy server: x11 request w/o originator_port"); 1680 originator_port = 0; 1681 } else { 1682 originator_port = packet_get_int(); 1683 } 1684 packet_check_eom(); 1685 /* XXX check permission */ 1686 debug("client_request_x11: request from %s %d", originator, 1687 originator_port); 1688 xfree(originator); 1689 sock = x11_connect_display(); 1690 if (sock < 0) 1691 return NULL; 1692 /* again is this really necessary for X11? */ 1693 if (options.hpn_disabled) 1694 c = channel_new("x11", 1695 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1696 CHAN_TCP_WINDOW_DEFAULT, CHAN_X11_PACKET_DEFAULT, 0, "x11", 1); 1697 else 1698 c = channel_new("x11", 1699 SSH_CHANNEL_X11_OPEN, sock, sock, -1, 1700 options.hpn_buffer_size, 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 if (options.hpn_disabled) 1721 c = channel_new("authentication agent connection", 1722 SSH_CHANNEL_OPEN, sock, sock, -1, 1723 CHAN_X11_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, 1724 "authentication agent connection", 1); 1725 else 1726 c = channel_new("authentication agent connection", 1727 SSH_CHANNEL_OPEN, sock, sock, -1, 1728 options.hpn_buffer_size, options.hpn_buffer_size, 0, 1729 "authentication agent connection", 1); 1730 c->force_drain = 1; 1731 return c; 1732 } 1733 1734 int 1735 client_request_tun_fwd(int tun_mode, int local_tun, int remote_tun) 1736 { 1737 Channel *c; 1738 int fd; 1739 1740 if (tun_mode == SSH_TUNMODE_NO) 1741 return 0; 1742 1743 if (!compat20) { 1744 error("Tunnel forwarding is not supported for protocol 1"); 1745 return -1; 1746 } 1747 1748 debug("Requesting tun unit %d in mode %d", local_tun, tun_mode); 1749 1750 /* Open local tunnel device */ 1751 if ((fd = tun_open(local_tun, tun_mode)) == -1) { 1752 error("Tunnel device open failed."); 1753 return -1; 1754 } 1755 1756 if(options.hpn_disabled) 1757 c = channel_new("tun", SSH_CHANNEL_OPENING, fd, fd, -1, 1758 CHAN_TCP_WINDOW_DEFAULT, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1); 1759 else 1760 c = channel_new("tun", SSH_CHANNEL_OPENING, fd, fd, -1, 1761 options.hpn_buffer_size, CHAN_TCP_PACKET_DEFAULT, 0, "tun", 1); 1762 c->datagram = 1; 1763 1764 packet_start(SSH2_MSG_CHANNEL_OPEN); 1765 packet_put_cstring("tun@openssh.com"); 1766 packet_put_int(c->self); 1767 packet_put_int(c->local_window_max); 1768 packet_put_int(c->local_maxpacket); 1769 packet_put_int(tun_mode); 1770 packet_put_int(remote_tun); 1771 packet_send(); 1772 1773 return 0; 1774 } 1775 1776 /* XXXX move to generic input handler */ 1777 static void 1778 client_input_channel_open(int type, u_int32_t seq, void *ctxt) 1779 { 1780 Channel *c = NULL; 1781 char *ctype; 1782 int rchan; 1783 u_int rmaxpack, rwindow, len; 1784 1785 ctype = packet_get_string(&len); 1786 rchan = packet_get_int(); 1787 rwindow = packet_get_int(); 1788 rmaxpack = packet_get_int(); 1789 1790 debug("client_input_channel_open: ctype %s rchan %d win %d max %d", 1791 ctype, rchan, rwindow, rmaxpack); 1792 1793 if (strcmp(ctype, "forwarded-tcpip") == 0) { 1794 c = client_request_forwarded_tcpip(ctype, rchan); 1795 } else if (strcmp(ctype, "x11") == 0) { 1796 c = client_request_x11(ctype, rchan); 1797 } else if (strcmp(ctype, "auth-agent@openssh.com") == 0) { 1798 c = client_request_agent(ctype, rchan); 1799 } 1800 /* XXX duplicate : */ 1801 if (c != NULL) { 1802 debug("confirm %s", ctype); 1803 c->remote_id = rchan; 1804 c->remote_window = rwindow; 1805 c->remote_maxpacket = rmaxpack; 1806 if (c->type != SSH_CHANNEL_CONNECTING) { 1807 packet_start(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION); 1808 packet_put_int(c->remote_id); 1809 packet_put_int(c->self); 1810 packet_put_int(c->local_window); 1811 packet_put_int(c->local_maxpacket); 1812 packet_send(); 1813 } 1814 } else { 1815 debug("failure %s", ctype); 1816 packet_start(SSH2_MSG_CHANNEL_OPEN_FAILURE); 1817 packet_put_int(rchan); 1818 packet_put_int(SSH2_OPEN_ADMINISTRATIVELY_PROHIBITED); 1819 if (!(datafellows & SSH_BUG_OPENFAILURE)) { 1820 packet_put_cstring("open failed"); 1821 packet_put_cstring(""); 1822 } 1823 packet_send(); 1824 } 1825 xfree(ctype); 1826 } 1827 static void 1828 client_input_channel_req(int type, u_int32_t seq, void *ctxt) 1829 { 1830 Channel *c = NULL; 1831 int exitval, id, reply, success = 0; 1832 char *rtype; 1833 1834 id = packet_get_int(); 1835 rtype = packet_get_string(NULL); 1836 reply = packet_get_char(); 1837 1838 debug("client_input_channel_req: channel %d rtype %s reply %d", 1839 id, rtype, reply); 1840 1841 if (id == -1) { 1842 error("client_input_channel_req: request for channel -1"); 1843 } else if ((c = channel_lookup(id)) == NULL) { 1844 error("client_input_channel_req: channel %d: " 1845 "unknown channel", id); 1846 } else if (strcmp(rtype, "eow@openssh.com") == 0) { 1847 packet_check_eom(); 1848 chan_rcvd_eow(c); 1849 } else if (strcmp(rtype, "exit-status") == 0) { 1850 exitval = packet_get_int(); 1851 if (id == session_ident) { 1852 success = 1; 1853 exit_status = exitval; 1854 } else if (c->ctl_fd == -1) { 1855 error("client_input_channel_req: unexpected channel %d", 1856 session_ident); 1857 } else { 1858 atomicio(vwrite, c->ctl_fd, &exitval, sizeof(exitval)); 1859 success = 1; 1860 } 1861 packet_check_eom(); 1862 } 1863 if (reply) { 1864 packet_start(success ? 1865 SSH2_MSG_CHANNEL_SUCCESS : SSH2_MSG_CHANNEL_FAILURE); 1866 packet_put_int(c->remote_id); 1867 packet_send(); 1868 } 1869 xfree(rtype); 1870 } 1871 static void 1872 client_input_global_request(int type, u_int32_t seq, void *ctxt) 1873 { 1874 char *rtype; 1875 int want_reply; 1876 int success = 0; 1877 1878 rtype = packet_get_string(NULL); 1879 want_reply = packet_get_char(); 1880 debug("client_input_global_request: rtype %s want_reply %d", 1881 rtype, want_reply); 1882 if (want_reply) { 1883 packet_start(success ? 1884 SSH2_MSG_REQUEST_SUCCESS : SSH2_MSG_REQUEST_FAILURE); 1885 packet_send(); 1886 packet_write_wait(); 1887 } 1888 xfree(rtype); 1889 } 1890 1891 void 1892 client_session2_setup(int id, int want_tty, int want_subsystem, 1893 const char *term, struct termios *tiop, int in_fd, Buffer *cmd, char **env) 1894 { 1895 int len; 1896 Channel *c = NULL; 1897 1898 debug2("%s: id %d", __func__, id); 1899 1900 if ((c = channel_lookup(id)) == NULL) 1901 fatal("client_session2_setup: channel %d: unknown channel", id); 1902 1903 if (want_tty) { 1904 struct winsize ws; 1905 1906 /* Store window size in the packet. */ 1907 if (ioctl(in_fd, TIOCGWINSZ, &ws) < 0) 1908 memset(&ws, 0, sizeof(ws)); 1909 1910 channel_request_start(id, "pty-req", 1); 1911 client_expect_confirm(id, "PTY allocation", 0); 1912 packet_put_cstring(term != NULL ? term : ""); 1913 packet_put_int((u_int)ws.ws_col); 1914 packet_put_int((u_int)ws.ws_row); 1915 packet_put_int((u_int)ws.ws_xpixel); 1916 packet_put_int((u_int)ws.ws_ypixel); 1917 if (tiop == NULL) 1918 tiop = get_saved_tio(); 1919 tty_make_modes(-1, tiop); 1920 packet_send(); 1921 /* XXX wait for reply */ 1922 c->client_tty = 1; 1923 } 1924 1925 /* Transfer any environment variables from client to server */ 1926 if (options.num_send_env != 0 && env != NULL) { 1927 int i, j, matched; 1928 char *name, *val; 1929 1930 debug("Sending environment."); 1931 for (i = 0; env[i] != NULL; i++) { 1932 /* Split */ 1933 name = xstrdup(env[i]); 1934 if ((val = strchr(name, '=')) == NULL) { 1935 xfree(name); 1936 continue; 1937 } 1938 *val++ = '\0'; 1939 1940 matched = 0; 1941 for (j = 0; j < options.num_send_env; j++) { 1942 if (match_pattern(name, options.send_env[j])) { 1943 matched = 1; 1944 break; 1945 } 1946 } 1947 if (!matched) { 1948 debug3("Ignored env %s", name); 1949 xfree(name); 1950 continue; 1951 } 1952 1953 debug("Sending env %s = %s", name, val); 1954 channel_request_start(id, "env", 0); 1955 packet_put_cstring(name); 1956 packet_put_cstring(val); 1957 packet_send(); 1958 xfree(name); 1959 } 1960 } 1961 1962 len = buffer_len(cmd); 1963 if (len > 0) { 1964 if (len > 900) 1965 len = 900; 1966 if (want_subsystem) { 1967 debug("Sending subsystem: %.*s", 1968 len, (u_char*)buffer_ptr(cmd)); 1969 channel_request_start(id, "subsystem", 1); 1970 client_expect_confirm(id, "subsystem", 1); 1971 } else { 1972 debug("Sending command: %.*s", 1973 len, (u_char*)buffer_ptr(cmd)); 1974 channel_request_start(id, "exec", 1); 1975 client_expect_confirm(id, "exec", 1); 1976 } 1977 packet_put_string(buffer_ptr(cmd), buffer_len(cmd)); 1978 packet_send(); 1979 } else { 1980 channel_request_start(id, "shell", 1); 1981 client_expect_confirm(id, "shell", 1); 1982 packet_send(); 1983 } 1984 } 1985 1986 static void 1987 client_init_dispatch_20(void) 1988 { 1989 dispatch_init(&dispatch_protocol_error); 1990 1991 dispatch_set(SSH2_MSG_CHANNEL_CLOSE, &channel_input_oclose); 1992 dispatch_set(SSH2_MSG_CHANNEL_DATA, &channel_input_data); 1993 dispatch_set(SSH2_MSG_CHANNEL_EOF, &channel_input_ieof); 1994 dispatch_set(SSH2_MSG_CHANNEL_EXTENDED_DATA, &channel_input_extended_data); 1995 dispatch_set(SSH2_MSG_CHANNEL_OPEN, &client_input_channel_open); 1996 dispatch_set(SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 1997 dispatch_set(SSH2_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 1998 dispatch_set(SSH2_MSG_CHANNEL_REQUEST, &client_input_channel_req); 1999 dispatch_set(SSH2_MSG_CHANNEL_WINDOW_ADJUST, &channel_input_window_adjust); 2000 dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &channel_input_status_confirm); 2001 dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &channel_input_status_confirm); 2002 dispatch_set(SSH2_MSG_GLOBAL_REQUEST, &client_input_global_request); 2003 2004 /* rekeying */ 2005 dispatch_set(SSH2_MSG_KEXINIT, &kex_input_kexinit); 2006 2007 /* global request reply messages */ 2008 dispatch_set(SSH2_MSG_REQUEST_FAILURE, &client_global_request_reply); 2009 dispatch_set(SSH2_MSG_REQUEST_SUCCESS, &client_global_request_reply); 2010 } 2011 2012 static void 2013 client_init_dispatch_13(void) 2014 { 2015 dispatch_init(NULL); 2016 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_close); 2017 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, &channel_input_close_confirmation); 2018 dispatch_set(SSH_MSG_CHANNEL_DATA, &channel_input_data); 2019 dispatch_set(SSH_MSG_CHANNEL_OPEN_CONFIRMATION, &channel_input_open_confirmation); 2020 dispatch_set(SSH_MSG_CHANNEL_OPEN_FAILURE, &channel_input_open_failure); 2021 dispatch_set(SSH_MSG_PORT_OPEN, &channel_input_port_open); 2022 dispatch_set(SSH_SMSG_EXITSTATUS, &client_input_exit_status); 2023 dispatch_set(SSH_SMSG_STDERR_DATA, &client_input_stderr_data); 2024 dispatch_set(SSH_SMSG_STDOUT_DATA, &client_input_stdout_data); 2025 2026 dispatch_set(SSH_SMSG_AGENT_OPEN, options.forward_agent ? 2027 &client_input_agent_open : &deny_input_open); 2028 dispatch_set(SSH_SMSG_X11_OPEN, options.forward_x11 ? 2029 &x11_input_open : &deny_input_open); 2030 } 2031 2032 static void 2033 client_init_dispatch_15(void) 2034 { 2035 client_init_dispatch_13(); 2036 dispatch_set(SSH_MSG_CHANNEL_CLOSE, &channel_input_ieof); 2037 dispatch_set(SSH_MSG_CHANNEL_CLOSE_CONFIRMATION, & channel_input_oclose); 2038 } 2039 2040 static void 2041 client_init_dispatch(void) 2042 { 2043 if (compat20) 2044 client_init_dispatch_20(); 2045 else if (compat13) 2046 client_init_dispatch_13(); 2047 else 2048 client_init_dispatch_15(); 2049 } 2050 2051 /* client specific fatal cleanup */ 2052 void 2053 cleanup_exit(int i) 2054 { 2055 leave_raw_mode(); 2056 leave_non_blocking(); 2057 if (options.control_path != NULL && muxserver_sock != -1) 2058 unlink(options.control_path); 2059 _exit(i); 2060 } 2061